Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
OXIDATION AND SUBLIMATION PREVENTION FOR THERMOELECTRIC DEVICES
Document Type and Number:
WIPO Patent Application WO/2017/066261
Kind Code:
A2
Abstract:
Thermoelectric systems comprising oxidation and/or sublimation resistant coatings, and methods for making the thermoelectric systems, are disclosed.

Inventors:
ARORA HITESH (US)
CRANE DOUGLAS T (US)
AGUIRRE MARIO (US)
REIFENBERG JOHN (US)
Application Number:
PCT/US2016/056558
Publication Date:
April 20, 2017
Filing Date:
October 12, 2016
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ALPHABET ENERGY INC (US)
International Classes:
H05B3/14; C08K3/10
Attorney, Agent or Firm:
GEISLER, Brian, T. et al. (US)
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1 . A thermoelectric device, comprising:

a hot-side substrate comprising a dielectric material and an electrical circuit; a plurality of thermoelectric elements, wherein each thermoelectric element is bonded to the hot-side substrate and electrically coupled to the electrical circuit, and wherein each thermoelectric element comprises:

a thermoelectric material; and

a coating applied to the thermoelectric material before the thermoelectric element is bonded to the hot-side substrate.

2. The thermoelectric device of Claim 1 , wherein the coating comprises a transition metal oxide.

3. The thermoelectric device of Claim 2, wherein the transition metal oxide comprises one or more of alumina, silica, titania, and zirconia.

4. The thermoelectric device of any of Claims 1 -3, wherein the coating comprises antimony oxide.

5. The thermoelectric device of Claim 4, wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony hexitatridecoxide, and stibiconite.

6. The thermoelectric device of any of Claims 1 -5, wherein the coating comprises a solvent-based silicone resin.

7. The thermoelectric device of any of Claims 1 -6, wherein the coating comprises a high-temperature stable organic polymer.

8. The thermoelectric device of any of Claims 1 -7, wherein the coating comprises an epoxy polymer.

9. The thermoelectric device of any of Claims 1 -8, wherein the dielectric material comprises a ceramic material.

10. The thermoelectric device of any of Claims 1 -9, wherein the dielectric material comprises a dielectric coating on a metal surface.

1 1 . The thermoelectric device of Claim 10, wherein the dielectric coating comprises one or more of alumina, zirconia, zirconia toughened alumina, silicon nitride, silicon carbide, and aluminum nitride.

12. The thermoelectric device of any of Claims 1 -1 1 , wherein the dielectric material comprises one or more of alumina, zirconia, zirconia toughened alumina, silicon nitride, silicon carbide, and aluminum nitride.

13. The thermoelectric device of any of Claims 1 -12, wherein the thermoelectric material comprises a semiconductor material.

14. The thermoelectric device of Claim 13, wherein the semiconductor material comprises tetrahedrite.

15. The thermoelectric device of Claim 13, wherein the semiconductor material comprises one or more of tetrahedrite, a silicide, a skutterudite material, a half- Heusler alloy, lead telluride, silicon-germanium, a zinc antimonide, a magnesium silicide stannide system solid solution, a magnesium silicide, a manganese silicide, and a bismuth chalcogenide material.

16. The thermoelectric device of any of Claims 1 -15, wherein the thermoelectric elements comprise pairs of thermoelectric legs consisting of an n-type

semiconductor leg and a p-type semiconductor leg that are arranged in a serial connection with each other through the electrical circuit and arranged in a parallel thermal connection between the hot-side substrate and a cold-side substrate.

17. The thermoelectric device of any of Claims 1 -16, wherein the electrical circuit comprises a plurality of metal pads, wherein the thermoelectric elements are bonded to the metal pads by an electrically-conductive bonding material, and wherein the electrically-conductive bonding material comprises one or more of an electrically- conductive adhesive, a silver sinter, a metal solder, a lead-free solder, and a lead- containing solder, and a metal-metal bonding material.

18. The thermoelectric device of any of Claims 1 -17, wherein the coating suppresses oxidation.

19. The thermoelectric device of any of Claims 1 -18, wherein the coating suppresses sublimation.

20. The thermoelectric device of any of Claims 1 -19, wherein the coating suppresses sublimation from antimony.

21 . The thermoelectric device of any of Claims 1 -20, wherein the coefficient of thermal expansion of the coating is similar to the coefficient of thermal expansion of the thermoelectric material.

22. The thermoelectric device of any of Claims 1 -21 , wherein the coefficient of thermal expansion of the coating is similar to the coefficient of thermal expansion of the dielectric material of the hot-side substrate.

23. The thermoelectric device of any of Claims 1 -22, further comprising a cold- side substrate, wherein the thermoelectric elements are bonded to the cold-side substrate, and wherein the coefficient of thermal expansion of the coating is similar to the coefficient of thermal expansion of the material of the cold-side substrate.

24. The thermoelectric device of Claim 23, wherein the cold-side substrate is comprised of a dielectric material which is different than the dielectric material of the hot-side substrate.

25. The thermoelectric device of Claim 23, wherein the cold-side substrate is comprised of a dielectric material which is the same as the dielectric material of the hot-side substrate.

26. The thermoelectric device of any of Claims 1 -25, wherein the coefficient of thermal expansion of the electrically-conductive bonding material is similar to the coefficient of thermal expansion of the thermoelectric material comprising the thermoelectric elements.

27. The thermoelectric device of any of Claims 1 -26, further comprising a heat exchanger in thermal communication with the hot-side substrate.

28. The thermoelectric device of any of Claims 1 -27, wherein the electrical circuit comprises discrete bonding zones on the hot-side substrate.

29. The thermoelectric device of Claim 28, wherein the discrete bonding zones on the hot-side substrate are not electrically connected on the hot-side substrate.

30. The thermoelectric device of Claim 29, further comprising a cold-side substrate, wherein the thermoelectric elements are bonded to the cold-side substrate, and wherein the discrete bonding zones on the hot-side substrate are electrically connected to one another by discrete bonding zones on the cold-side substrate.

31 . The thermoelectric device of Claim 30, wherein the electrical circuit comprises discrete bonding zones on the cold-side substrate.

32. The thermoelectric device of Claim 31 , wherein the discrete bonding zones on the cold-side substrate are not electrically connected on the cold-side substrate.

33. The thermoelectric device of Claim 32, wherein the discrete bonding zones on the cold-side substrate are electrically connected to one another by discrete bonding zones on the hot-side substrate.

34. The thermoelectric device of any of Claims 28-33, wherein the discrete bonding zones are electrically connected by at least one shunt.

35. The thermoelectric device of any of Claims 1 -34, wherein the electrical circuit is applied to the hot-side substrate using a stencil printing process.

36. The thermoelectric device of any of Claims 1 -35, wherein the electrical circuit comprises a flux.

37. The thermoelectric device of Claim 36, wherein the flux comprises a rosin flux.

38. The thermoelectric device of any of Claims 1 -37, wherein the thermoelectric elements are bonded to the electrical circuit using silver.

39. The thermoelectric device of any of Claims 1 -38, wherein the thermoelectric elements are attached to the electrical circuit by a reflow soldering process.

40. The thermoelectric device of any of Claims 1 -39, wherein the electrical circuit is formed from a powdered metal.

41 . The thermoelectric device of any of Claims 1 -40, wherein the electrical circuit is formed from a glass frit.

42. The thermoelectric device of any of Claims 1 -41 , wherein the hot-side substrate is part of a heat exchanger.

43. The thermoelectric device of any of Claims 1 -42, wherein the hot-side substrate is directly integrated into a heat exchanger.

44. A thermoelectric device, comprising:

a hot-side substrate comprising a dielectric material and an electrical circuit; a plurality of thermoelectric elements, wherein each thermoelectric element is bonded to the hot-side substrate and is electrically coupled to the electrical circuit; and

a poured coating applied to the hot-side substrate and the thermoelectric elements.

45. The thermoelectric device of Claim 44, wherein the poured coating comprises a transition metal oxide.

46. The thermoelectric device of Claim 45, wherein the transition metal oxide comprises one or more of alumina, silica, titania, and zirconia.

47. The thermoelectric device of any of Claims 44-46, wherein the poured coating comprises antimony oxide.

48. The thermoelectric device of Claim 47, wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony hexitatridecoxide, and stibiconite.

49. The thermoelectric device of any of Claims 44-48, wherein the poured coating comprises a solvent-based silicone resin.

50. The thermoelectric device of any of Claims 44-49, wherein the poured coating comprises a high-temperature stable organic polymer.

51 . The thermoelectric device of any of Claims 44-50, wherein the poured coating comprises an epoxy polymer.

52. The thermoelectric device of any of Claims 44-51 , wherein the electrical circuit comprises metal pads, wherein the thermoelectric elements are bonded to the metal pads, and wherein the poured coating is also applied to the metal pads.

53. The thermoelectric device of Claim 52, wherein the poured coating is applied to the metal pads after the thermoelectric elements are bonded to the metal pads.

54. The thermoelectric device of any of Claims 44-53, wherein a second coating is applied to the thermoelectric elements before the thermoelectric elements are bonded to the hot-side substrate.

55. The thermoelectric device of Claim 54, wherein the second coating is comprised of a different material than the poured coating.

56. The thermoelectric device of any of Claims 44-55, further comprising a cold- side substrate, wherein each thermoelectric element is bonded to the cold-side substrate and is electrically coupled to the electrical circuit, and wherein the poured coating is poured between the hot-side substrate and the cold-side substrate.

57. The thermoelectric device of Claim 56, wherein the poured coating is poured between the hot-side substrate and the cold-side substrate while the hot-side substrate and the cold-side substrate are bonded to the thermoelectric elements.

58. The thermoelectric device of any of Claims 54-57, wherein each

thermoelectric element comprises an outer surface, and wherein the second coating is applied to less than the entirety of the outer surface.

59. The thermoelectric device of Claim 58, wherein the outer surface of each thermoelectric element comprises a bonding portion which is bonded to the hot-side substrate, and wherein the second coating is not on the bonding portion.

60. The thermoelectric device of Claim 59, further comprising a cold-side substrate, wherein each thermoelectric element comprises a second bonding portion which is bonded to the cold-side substrate, and wherein the second coating is not on the second bonding portion.

61 . The thermoelectric device of any of Claims 54-57, wherein each

thermoelectric element comprises an outer surface, and wherein the second coating is applied to the entirety of the outer surface.

62. A thermoelectric device, comprising:

a hot-side substrate comprising a dielectric material;

a cold-side substrate comprising a dielectric material;

an electrical circuit; a plurality of thermoelectric elements, wherein each thermoelectric element is bonded to the hot-side substrate and the cold-side substrate and is electrically coupled to the electrical circuit; and

a poured coating which is poured between the hot-side substrate and the cold-side substrate after the hot-side substrate and the cold-side substrate have been bonded to the thermoelectric elements.

63. The thermoelectric device of Claim 62, wherein the poured coating comprises a transition metal oxide.

64. The thermoelectric device of Claim 63, wherein the transition metal oxide comprises one or more of alumina, silica, titania, and zirconia.

65. The thermoelectric device of any of Claims 62-64, wherein the poured coating comprises antimony oxide.

66. The thermoelectric device of Claim 65, wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony hexitatridecoxide, and stibiconite.

67. The thermoelectric device of any of Claims 62-66, wherein the poured coating comprises a solvent-based silicone resin.

68. The thermoelectric device of any of Claims 62-67, wherein the poured coating comprises a high-temperature stable organic polymer.

69. The thermoelectric device of any of Claims 62-68, wherein the poured coating material comprises an epoxy polymer.

70. The thermoelectric device of any of Claims 62-69, wherein the electrical circuit comprises metal pads, wherein the thermoelectric elements are bonded to the metal pads, and wherein the poured coating is also applied to the metal pads.

71 . The thermoelectric device of Claim 70, wherein the poured coating covers the perimeter of each metal pad.

72. The thermoelectric device of any of Claims 62-71 , wherein a second coating is applied to the thermoelectric elements before the thermoelectric elements are bonded to the hot-side substrate and the cold-side substrate.

73. The thermoelectric device of Claim 72, wherein the second coating is different than the poured coating.

74. The thermoelectric device of Claim 72, wherein the second coating is the same as the poured coating.

75. A thermoelectric device, comprising:

a substrate comprising a dielectric material and an electrical circuit;

a plurality of thermoelectric elements, wherein each thermoelectric element is bonded to the substrate and is electrically coupled to the electrical circuit, and wherein each thermoelectric elements is comprised of a thermoelectric material having crevices therein; and

a dispensed coating which has penetrated the crevices of the thermoelectric elements via capillary action after the thermoelectric elements have been bonded to the substrate.

76. The thermoelectric device of Claim 75, wherein the dispensed coating comprises a transition metal oxide.

77. The thermoelectric device of Claim 76, wherein the transition metal oxide comprises one or more of alumina, silica, titania, and zirconia.

78. The thermoelectric device of any of Claims 75-77, wherein the dispensed coating comprises antimony oxide.

79. The thermoelectric device of Claim 75, wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony hexitatridecoxide, and stibiconite.

80. The thermoelectric device of any of Claims 75-79, wherein the dispensed coating comprises a solvent-based silicone resin.

81 . The thermoelectric device of any of Claims 75-80, wherein the dispensed coating comprises a high-temperature stable organic polymer.

82. The thermoelectric device of any of Claims 75-81 , wherein the dispensed coating material comprises an epoxy polymer.

83. The thermoelectric device of any of Claims 75-82, wherein the electrical circuit comprises metal pads, wherein the thermoelectric elements are bonded to the metal pads, and wherein the dispensed coating is also applied to the metal pads.

84. The thermoelectric device of Claim 83, wherein the dispensed coating covers the perimeter of each metal pad.

85. The thermoelectric device of any of Claims 75-84, wherein a second coating is applied to the thermoelectric elements before the thermoelectric elements are bonded to the substrate.

86. The thermoelectric device of Claim 85, wherein the second coating is comprised of a different material than the dispensed coating.

87. The thermoelectric device of Claim 85, wherein the second coating is comprised of the same material as the dispensed coating.

88. A thermoelectric device, comprising:

a substrate comprising an electrical circuit; a plurality of thermoelectric elements, wherein each thermoelectric element is bonded to the substrate and electrically coupled to the electrical circuit, and wherein each thermoelectric element comprises:

a thermoelectric material; and

a coating applied to the thermoelectric material before the thermoelectric element is bonded to the substrate.

89. The thermoelectric device of Claim 88, wherein the coating comprises a transition metal oxide.

90. The thermoelectric device of Claim 89, wherein the transition metal oxide comprises one or more of alumina, silica, titania, and zirconia.

91 . The thermoelectric device of any of Claims 88-90, wherein the coating comprises antimony oxide.

92. The thermoelectric device of Claim 91 , wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony hexitatridecoxide, and stibiconite.

93. The thermoelectric device of any of Claims 88-92, wherein the coating comprises a solvent-based silicone resin.

94. The thermoelectric device of any of Claims 88-93, wherein the coating comprises a high-temperature stable organic polymer.

95. The thermoelectric device of any of Claims 88-94, wherein the coating comprises an epoxy polymer.

96. The thermoelectric device of any of Claims 88-95, further comprising a poured coating poured onto the thermoelectric elements after the thermoelectric elements have been bonded to the substrate.

97. The thermoelectric device of Claim 96, wherein the poured coating is comprised of a different material than the coating.

98. The thermoelectric device of Claim 96, wherein the poured coating is comprised of the same material as the coating.

99. The thermoelectric device of any of Claims 88-98, wherein each

thermoelectric element comprises an outer surface, and wherein the coating is applied to less than the entirety of the outer surface.

100. The thermoelectric device of Claim 99, wherein the outer surface of each thermoelectric element comprises a bonding portion which is bonded to the substrate, and wherein the coating is not on the bonding portion.

101 . The thermoelectric device of Claim 100, further comprising a second substrate, wherein each thermoelectric element comprises a second bonding portion which is bonded to the second substrate, and wherein the coating is not on the second bonding portion.

102. The thermoelectric device of any of Claims 88-95, wherein each

thermoelectric element comprises an outer surface, and wherein the coating is applied to the entirety of the outer surface.

103. The thermoelectric device of any of Claims 88-102, wherein the thermoelectric elements comprise n-type semiconductor legs and p-type semiconductor legs, wherein the n-type semiconductor legs are at least partially coated by the coating, and wherein the p-type semiconductor legs are not coated by the coating.

104. The thermoelectric device of any of Claims 88-102, wherein the thermoelectric elements comprise n-type semiconductor legs and p-type semiconductor legs, wherein the p-type semiconductor legs are at least partially coated by the coating, and wherein the n-type semiconductor legs are not coated by the coating.

105. The thermoelectric device of any of Claims 88-102, wherein the thermoelectric elements comprise n-type semiconductor legs and p-type semiconductor legs, wherein the n-type semiconductor legs are at least partially coated by the coating, and wherein the p-type semiconductor legs are coated by a second coating.

106. A thermoelectric device, comprising:

a hot-side substrate comprising a dielectric material;

a cold-side substrate comprising a dielectric material;

an electrical circuit;

a plurality of thermoelectric elements, wherein each thermoelectric element is bonded to the hot-side substrate and the cold-side substrate and is electrically coupled to the electrical circuit, and wherein the thermoelectric elements are arranged in an array comprising an outer perimeter; and

a coating seal extending around the outer perimeter of the thermoelectric element array.

107. The thermoelectric device of Claim 106, wherein the coating seal comprises a transition metal oxide.

108. The thermoelectric device of Claim 107, wherein the transition metal oxide comprises one or more of alumina, silica, titania, and zirconia.

109. The thermoelectric device of any of Claims 106-108, wherein the coating seal comprises enamel.

1 10. The thermoelectric device of any of Claims 106-109, wherein the coating seal comprises antimony oxide.

1 1 1 . The thermoelectric device of Claim 1 10, wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony hexitatridecoxide, and stibiconite.

1 12. The thermoelectric device of any of Claims 106-1 1 1 , wherein the coating seal comprises a solvent-based silicone resin.

1 13. The thermoelectric device of any of Claims 106-1 12, wherein the coating seal comprises a high-temperature stable organic polymer.

1 14. The thermoelectric device of any of Claims 106-1 13, wherein the coating seal comprises an epoxy polymer.

1 15. The thermoelectric device of any of Claims 106-1 14, further comprising a poured coating poured onto the thermoelectric elements after the thermoelectric elements have been bonded to the hot-side substrate and the cold-side substrate.

1 16. The thermoelectric device of Claim 1 15, wherein the poured coating is comprised of a different material than the coating seal.

1 17. The thermoelectric device of Claim 1 15, wherein the poured coating is comprised of the same material as the coating seal.

1 18. A method of forming a thermoelectric system for prevention of oxidation and sublimation of a thermoelectric element material during high temperature use in a thermoelectric system, comprising the steps of:

providing a plurality of thermoelectric elements comprising a thermoelectric material;

coating a portion of each of the plurality of thermoelectric elements that will be exposed to air during operation in a thermoelectric system with a coating material that prevents oxidation and sublimation of the thermoelectric material at a

thermoelectric system operating temperature;

assembling the plurality of coated thermoelectric elements into a plurality of electrical connectors comprising a bonding material on a substrate such that an uncoated portion of each thermoelectric element makes an electrical connection with the bonding material of the plurality of electrical connectors; and

assembling a second substrate to the plurality of thermoelectric elements to form a thermoelectric system.

1 19. The method of Claim 1 18, wherein the coating material comprises a transition metal oxide, wherein the transition metal oxide electrically and thermally insulates the thermoelectric material of the thermoelectric element.

120. The method of Claim 1 18 or 1 19, wherein the coating material comprises one or more of alumina, silica, titania, and zirconia.

121 . The method of any of Claims 1 18-120, wherein the coating material comprises an additive to reduce sublimation of the thermoelectric material at the thermoelectric system operating temperature.

122. The method of Claim 121 , wherein the additive comprises an antimony oxide.

123. The method of Claim 122, wherein the antimony oxide comprises one or more of diantimony tetroxide, antimony trioxide, antimony pentoxide, antimony

hexitatridecoxide, and stibiconite.

124. The method of any of Claims 1 18-123, wherein the coating comprises enamel.

125. The method of any of Claims 1 18-124, wherein the thickness of the coating is in a range of 25-100 micrometers.

126. The method of any of Claims 1 18-125, wherein the thickness of the coating is in a range of 0.1 -1 .0 microns.

127. The method of any of Claims 1 18-125, wherein the thickness of the coating is at least 0.1 microns.

128. The method of any of Claims 1 18-126, wherein the coating step comprises at least one of spray coating, dip coating, atomic layer deposition coating, and capillary flow coating.

129. The method of Claim 128, further comprising a step of curing the coating in a temperature range of 90°-230°C.

130. A method for preventing oxidation and sublimation of component materials of a thermoelectric system, comprising the steps of:

bonding a plurality of thermoelectric elements comprising a thermoelectric material to a dielectric substrate, wherein the thermoelectric material comprises crevices defined therein;

coating at least a portion of the thermoelectric elements with a coating material, wherein the coating material is sufficiently viscous to enter into the crevices of the thermoelectric material by capillary action; and

assembling a second dielectric substrate to the thermoelectric elements to form a thermoelectric system after the coating step.

131 . The method of Claim 130, further comprising the step of heating the coating material prior to the coating step.

132. The method of Claim 130 or 131 , wherein the coating step comprises dispensing the coating material onto the thermoelectric elements and orienting the dielectric substrate such that the coating material flows over the thermoelectric elements.

133. The method of any of Claims 130-132, wherein the coating step comprises dispensing enough coating material onto the thermoelectric elements such that the coating material pools on the dielectric substrate.

134. The method of any of Claims 130-133, further comprising the step of curing the coating material after the coating step.

135. The method of any of Claims 130-134, wherein the coating material is thickest adjacent the dielectric substrate and thinnest adjacent the second dielectric substrate.

136. The method of any of Claims 130-134, wherein the coating material is thickest adjacent the dielectric substrate and absent from the thermoelectric elements adjacent the second dielectric substrate.

137. The method of any of Claims 130-134, further comprising the step of applying a coating material to the thermoelectric elements prior to the bonding step.

138. The method of any of Claims 130-137, wherein the dielectric substrate comprises a hot-side substrate and the second dielectric substrate comprises a cold- side substrate.

139. The method of any of Claims 130-138, wherein the coating material comprises a high-temperature stable organic polymer.

140. The method of Claim 139, wherein the high-temperature stable organic polymer comprises an epoxy polymer.

141 . The method of any of Claims 130-140, wherein the coating material comprises a high-temperature stable silicone resin.

142. The method of any of Claims 130-141 , wherein the coating material further comprises inorganic fillers.

143. The method of Claim 142, wherein the inorganic fillers comprise a transition metal oxide.

144. The method of Claim 143, wherein the transition metal oxide comprise one or more of alumina, silica, titania, and zirconia.

145. The method of any of Claims 130-144, wherein a thickness of the coating material is in a range of 25-100 micrometers.

146. The method of any of Claims 130-145, wherein the capillary flow coating step is performed in a temperature range of 90°-1 10°C.

147. A method for generating an electrical current, comprising the step of integrating the thermoelectric device of any of Claims 1 -146 to a heat source.

148. A method for generating a temperature differential, comprising the step of applying a voltage to the thermoelectric device of any of Claims 1 -146.

149. A thermoelectric device of any of Claims 1 -146, wherein the thermoelectric device is used as a Peltier device.

150. A thermoelectric device of any of Claims 1 -146, wherein the thermoelectric device is used as a Seebeck device.

Description:
TITLE

OXIDATION AND SUBLIMATION PREVENTION FOR THERMOELECTRIC

DEVICES

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit under 35 U.S.C. §1 19(e) of the earlier filing date of United States Provisional Patent Application No. 62/240,533, filed on October 13, 2015, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND

[0002] Thermoelectric devices can convert heat energy into electrical energy. A thermoelectric device can comprise a hot junction, or hot side, a cold junction, or cold side, and one or more thermoelectric elements positioned between the hot junction and the cold junction. Oftentimes, the hot junction and the cold junction each comprise a plate, for example, positioned against and/or bonded to the opposite sides of the thermoelectric elements. The thermoelectric elements are comprised of thermoelectric materials, such as semiconductors, for example. When such thermoelectric devices are subjected to a temperature differential between their hot junction and cold junction, they can generate a voltage potential which is utilizable for any suitable purpose. Such thermoelectric devices are often referred to as Seebeck devices. Some thermoelectric devices can convert electrical energy to heat energy. When such thermoelectric devices are subjected to a voltage potential, they can generate a temperature differential between a first junction and a second junction. Such thermoelectric devices are often referred to as Peltier devices. In either event, the energy conversion efficiency of a thermoelectric device can be measured by its thermal power density, also known as its "thermoelectric figure of merit" ΖΓ, where ZT is equal to TS 2 O/K and where 7 " is the temperature, S the Seebeck coefficient, a the electrical conductivity, and ( the thermal conductivity of the thermoelectric material utilized by the thermoelectric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Various features of the embodiments described herein, together with advantages thereof, may be understood in accordance with the following description taken in conjunction with the accompanying drawings:

[0004] FIG. 1 is an exploded view of a thermoelectric device in accordance with at least one embodiment;

[0005] FIG. 2 is a plan view of a thermoelectric sub-assembly of the thermoelectric device of FIG. 1 illustrated with some components removed for the purpose of illustration;

[0006] FIG. 3 is a cross-sectional view of a portion of the thermoelectric subassembly of FIG. 2;

[0007] FIG. 4 is a cross-sectional view of a portion of a thermoelectric subassembly comprising bonded thermoelectric elements that are coated with an oxidation and/or sublimation resistant coating in accordance with at least one embodiment;

[0008] FIG. 4A illustrates a method for coating thermoelectric elements before assembling them to a substrate of a thermoelectric sub-assembly in accordance with at least one embodiment;

[0009] FIG. 5A is a cross-sectional view of a portion of a thermoelectric subassembly comprising bonded thermoelectric elements in accordance with at least one embodiment;

[0010] FIG. 5B is a cross-sectional view of the thermoelectric sub-assembly of FIG. 5A coated with an oxidation and/or sublimation resistant coating in accordance with at least one embodiment;

[0011] FIG. 5C illustrates a method for coating thermoelectric elements after assembling them to a substrate of a thermoelectric sub-assembly in accordance with at least one embodiment;

[0012] FIG. 6A is a cross-sectional view of a portion of a thermoelectric subassembly comprising thermoelectric elements in accordance with at least one embodiment;

[0013] FIG. 6B is a cross-sectional view of the thermoelectric sub-assembly of FIG. 6A illustrating an oxidation and/or sublimation resistant coating between the thermoelectric elements and extending around the outer perimeter of the

thermoelectric elements; [0014] FIG. 6C illustrates a method for coating a thermoelectric sub-assembly comprising thermoelectric elements in accordance with at least one embodiment;

[0015] FIG. 7A is a cross-sectional view of a portion of a thermoelectric subassembly comprising thermoelectric elements in accordance with at least one embodiment;

[0016] FIG. 7B is a cross-sectional view of the thermoelectric sub-assembly of FIG. 7A illustrating an oxidation and/or sublimation resistant coating extending around the outer perimeter of the thermoelectric elements;

[0017] FIG. 8A is a cross-section of a thermoelectric element comprising a spray coating after being exposed to a temperature of 400°C for 99 hours;

[0018] FIG. 8B is a cross-section of the thermoelectric element of FIG. 8A after being exposed to a temperature of 400°C for an additional 50 hours;

[0019] FIG. 9A is a cross-section of a thermoelectric element comprising a spray coating after being exposed to a temperature of 400°C for 123 hours; and

[0020] FIG. 9B is a cross-section of the thermoelectric element of FIG. 9A after being exposed to a temperature of 400°C for an additional 50 hours.

[0021] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate various embodiments of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION

[0022] Thermoelectric systems generally comprise a hot side, a cold side, and a thermoelectric assembly positioned therebetween. The hot side of the

thermoelectric system often comprises a plate facing a heat source, i.e., a hot-side plate, and, similarly, the cold side often comprises a plate facing a heat sink, i.e., a cold-side plate. In use, heat flows through the thermoelectric assembly from the hot- side plate toward the cold-side plate which, in turn, generates electrical power within the thermoelectric assembly. In various instances, a thermoelectric system can be configured to harvest thermal energy from more than one heat source and/or discharge thermal energy to more than one heat sink. Moreover, a thermoelectric system can comprise more than one thermoelectric assembly configured to convert thermal energy to electrical energy. [0023] A thermoelectric system, or thermoelectric generating unit (TGU), 100 is illustrated in FIG. 1 . The TGU 100 comprises a first cold-side plate 1 10, a hot-side heat exchanger 120, and a second cold-side plate 130. The TGU 100 further comprises a first thermoelectric assembly 160 and a second thermoelectric assembly 170. The first thermoelectric assembly 160 is positioned intermediate the first cold-side plate 1 10 and a first side 126 of the hot-side heat exchanger 120. The second thermoelectric assembly 170 is positioned intermediate the second cold-side plate 130 and a second side 127 of the hot-side heat exchanger 120. The TGU 100 also comprises lateral sides 125 positioned intermediate the first cold-side plate 1 10 and the second cold-side plate 130. The entire disclosure of International

Publication Number WO 2016/054333, entitled THERMOELECTRIC GENERATING UNIT AND METHODS OF MAKING AND USING SAME, which published on April 7, 2016, is incorporated by reference herein.

[0024] The TGU 100 further comprises a first insulation layer 150, a second insulation layer 180, and a plurality of fasteners 1 15. The first insulation layer 150 is positioned intermediate the first thermoelectric assembly 160 and the first cold-side plate 1 10. The second insulation layer 180 is positioned intermediate the second thermoelectric assembly 170 and the second cold-side plate 130. Fasteners 1 15 are positioned within apertures which extend through the first cold-side plate 1 10, the first insulation layer 150, the first thermoelectric assembly 160, the hot-side heat exchanger 120, the second thermoelectric assembly 170, the second insulation layer 180, and the second cold-side plate 130 and can clamp these components together such that satisfactory thermal contact between these components is maintained under a variety of operating conditions.

[0025] The hot-side heat exchanger 120 comprises a plurality of discrete channels 121 . Each channel 121 is configured to receive a fluid carrying waste heat such as, for example, exhaust from an engine. Each channel 121 comprises a fluidic inlet, a fluidic outlet 128, and a lumen that fluidically couples the fluidic inlet and the fluidic outlet 128. Each channel 121 is sealed from the other channels 121 and, concurrently, sealed from the other internal portions of the TGU 100. The lumen is configured to efficiently extract heat from a fluid passing there through in the direction indicated by arrow 1 12, for example. In at least one instance, the channels 121 comprise fins disposed within and extending into the lumens defined therein. The fins can be arranged in a fin pack in the lumen and can comprise any suitable configuration, as described below.

[0026] Further to the above, any suitable arrangement, number, and density of fins within the channels 121 can be used. For instance, the density of the fins within the channels 121 can be at least 12 fins per inch, for example. In various instances, the channels 121 and/or the fins disposed therein are comprised of stainless steel, nickel plated copper, and/or stainless steel clad copper, for example. Such designs are configured to increase the contact area between the hot fluid and the sidewalls of the channels 121 which, as a result, increases the heat transfer between the hot fluid and the hot-side heat exchanger 120. Moreover, such designs are configured to disrupt the boundary layer of the fluid flowing through the channels 121 which also increases the heat transfer between the hot fluid and the hot-side heat exchanger 120.

[0027] In at least one instance, the hot-side heat exchanger 120 comprises a high efficiency hot-side heat exchanger. As used herein, a high efficiency hot-side heat exchanger is intended to mean a hot-side heat exchanger characterized by a thermal resistance of less than about 0.0015m 2 K/W, for example. In at least one such instance, the thermal resistance of a hot-side heat exchanger is 0.00025 m 2 K/W, for example. In various instances, the cold-side plates 1 10 and 130 comprise high efficiency cold-side heat exchangers. As used herein, a high efficiency cold-side heat exchanger is intended to mean a cold-side heat exchanger characterized by a thermal resistance of less than about 0.0001 m 2 K/W, for example.

[0028] The first cold-side plate 1 10 and the second cold-side plate 130 are flat, or at least substantially flat. As used herein, a substantially flat plate is intended to mean that the first and second major surfaces are substantially planar and parallel to one another. In at least one instance, a substantially flat plate is characterized by a flatness and planarity specification of about 0.010" or less across the major surfaces, for example. The cold-side plates 1 10 and 130 comprise a substantially flat slab of a thermally conductive material, such as a metal and/or a ceramic, for example.

Metals that are suitable for use in the first cold-side plate 1 10 and/or the second cold-side plate 130 can be selected from the group consisting of aluminum, copper, molybdenum, tungsten, copper-molybdenum alloy, stainless steel, nickel, and/or alloys of one or more of these materials, for example. Ceramics that are suitable for use in the first cold-side plate 1 10 and/or the second cold-side plate 130 can be selected from the group consisting of silicon carbide, aluminum nitride, alumina, silicon nitride and/or combinations thereof, for example. In at least one embodiment, one of the cold-side plates 1 10 and 130 is comprised of a metal and the other of the cold-side plates 1 10 and 130 is comprised of a ceramic, for example.

[0029] In various instances, further to the above, the first thermoelectric assembly 160 and the second thermoelectric assembly 170 are part of an electrical circuit of the TGU 100. The thermoelectric assemblies 160 and 170 are electrically connected in series with one another. Alternatively, the thermoelectric assemblies 160 and 170 are electrically connected in parallel with one another. In either event, the electrical circuit of the TGU 100 further comprises an electrical connector comprising at least a first electrical terminal and a second electrical terminal. In use, the thermoelectric assemblies 160 and 170 create a voltage differential between the first electrical terminal and the second electrical terminal.

[0030] The thermoelectric assembly 160, further to the above, is comprised of a plurality of sub-assemblies, or cards, wherein each sub-assembly comprises a plurality of thermoelectric elements 190 mounted thereto. Similarly, referring to FIG. 2, the thermoelectric assembly 170 is comprised of a plurality of sub-assemblies, or cards, 170' wherein each sub-assembly 170' also comprises a plurality of

thermoelectric elements 190 mounted thereto. The sub-assemblies 170' are mounted to and supported by a printed circuit board (PCB) of the thermoelectric assembly 170. The thermoelectric assembly 170 comprises 80 sub-assemblies 170', for example; however, a thermoelectric assembly can comprise any suitable number of sub-assemblies 170'. The sub-assemblies 170' of the thermoelectric assembly 170 are electrically connected in series as part of an electrical circuit extending through the thermoelectric assembly 170. That said, the sub-assemblies 170' can be electrically connected in parallel and/or in series with one other in any suitable arrangement. It should also be appreciated that a sub-assembly 170' can be used by itself, i.e., without other sub-assemblies 170'.

[0031] Further to the above, each thermoelectric sub-assembly 170' comprises a substrate and a plurality of thermoelectric elements 190 mounted to the substrate. The substrate of each sub-assembly 170' can comprise a PCB and/or any suitable dielectric material. As described in greater detail below, the substrate comprises a trace circuit and the thermoelectric elements 190 are bonded to the trace circuit. Each sub-assembly 170' comprises 48 thermoelectric elements 190 mounted thereto; however, a thermoelectric sub-assembly can comprise any suitable number of thermoelectric elements 190. The thermoelectric elements 190 mounted to a subassembly 170' are electrically connected to each other in series. That said, the thermoelectric elements 190 mounted to a thermoelectric sub-assembly can be electrically connected in parallel and/or in series with one other in any suitable arrangement.

[0032] Further to the above, the thermoelectric elements 190 of each

thermoelectric sub-assembly 170' are arranged in a rectangular array of columns and rows between the second cold-side plate 130 and the second side 127 of the hot-side heat exchanger 120. That said, any suitable arrangement can be used.

[0033] Thermoelectric elements can comprise any suitable configuration. Each thermoelectric element 190 comprises two thermoelectric legs; however, a thermoelectric element can comprise one or more thermoelectric legs. Each thermoelectric leg comprises a thermoelectric material disposed between first and second conductive materials. A thermoelectric material can be selected from the group consisting of tetrahedrite, magnesium silicide (Mg 2 Si), magnesium silicide stannide (Mg 2 (SiSn)), silicon, silicon nanowire, bismuth telluride (Bi 2 Te 3 ), a skutterudite material, lead telluride (PbTe), TAGS (tellurium-antimony-germanium- silver alloys), a zinc antimonide, silicon-germanium (SiGe), a half-Heusler alloy, and combinations thereof, for example.

[0034] A thermoelectric leg can comprise a p-type thermoelectric material or a n- type thermoelectric material. A p-type thermoelectric material is comprised of at least one p-doped semiconductor material, for example. A n-type thermoelectric material is comprised of at least one n-doped semiconductor material, for example. Turning now to FIG. 2, each thermoelectric element 190 of the thermoelectric assemblies 160 and 170 comprises a n-type thermoelectric leg 194 and a p-type thermoelectric leg 196. In at least one such embodiment, the p-type thermoelectric legs 196 are larger than the n-type thermoelectric legs 194. In alternative

embodiments, the legs 196 are n-type thermoelectric legs and the legs 194 are p- type thermoelectric legs. In certain embodiments, the n-type legs and the p-type legs are the same size. In at least one instance, one or more of the n-type thermoelectric legs 194 are connected electrically in series and thermally in parallel with one or more of the p-type thermoelectric legs 196 so as to generate an electrical current responsive to a temperature differential across the thermoelectric assemblies 160 and 170.

[0035] Further to the above, the quantity of thermoelectric elements 190 in the first thermoelectric assembly 160 and the quantity of thermoelectric elements 190 in the second thermoelectric assembly 170 are the same. In at least one such instance, the first thermoelectric assembly 160 and the second thermoelectric assembly 170 have the same number of sub-assemblies, or cards (such as sub-assemblies 170'), wherein the sub-assemblies each have the same number of thermoelectric elements 190 mounted thereto. Moreover, the thermoelectric assemblies 160 and 170 each have an equal number of n-type legs 194 and p-type legs 196; however, other embodiments are envisioned in which the quantities of n-type legs 194 and p-type legs 196 in a thermoelectric assembly are different. The above being said, embodiments are envisioned in which the quantity of thermoelectric elements 190 in the first thermoelectric assembly 160 and the quantity of thermoelectric elements 190 in the second thermoelectric assembly 170 are different.

[0036] Further to the above, the fasteners 1 15 can extend through gaps defined between the thermoelectric elements 190 and/or gaps defined between the subassemblies, or cards, of the thermoelectric assemblies 160 and 170, for example. Also, further to the above, the fasteners 1 15 can be tightened to clamp the first cold- side plate 1 10, the first insulation layer 150, the first thermoelectric assembly 160, the hot-side heat exchanger 120, the second thermoelectric assembly 170, the second insulation layer 180, and the second cold-side plate 130 together such that the thermoelectric elements 190 are compressed against the hot-side heat exchanger 120 without interrupting the electrical connection between the

thermoelectric elements 190 and/or between the sub-assemblies, or cards, of the thermoelectric assemblies 160 and 170.

[0037] A thermoelectric sub-assembly 170' of the thermoelectric assembly 170 is illustrated in FIG. 2. The thermoelectric sub-assembly 170' comprises a substrate 172 and a plurality of metal pads 192 mounted to the substrate 172. The metal pads 192 comprise direct bond copper (DBC) pads, for example, which are part of the electrical circuit of the thermoelectric sub-assembly 170'. In addition to or in lieu of the DBC pads, the metal pads 192 can comprise active metal brazing (AMB) pads, for example. The substrate 172 is comprised of a dielectric material and does not conduct current between the thermoelectric elements 190 and the metal pads 192. The thermoelectric legs 194 and 196 of the thermoelectric elements 190 are electrically and mechanically connected to the metal pads 192 through a bonding material.

[0038] In at least one instance, further to the above, the substrate 172 is comprised of alumina and the thermoelectric legs 194 and 196 are comprised of bismuth telluride (Bi 2 Te 3 ) blocks which are soldered to the metal pads 192, for example. In at least one instance, the substrate 172 is comprised of alumina and the thermoelectric legs 194 and 196 are comprised of tetrahedrite blocks which are soldered to the metal pads 192, for example. In either event, the solder may be any suitable solder, such as lead/tin eutectic solder, lead-free solders, and/or silver solders, for example. A reflow soldering process, for example, is utilized to bond the thermoelectric legs 194 and 196 to the metal pads 192. In at least one such instance, the thermoelectric sub-assembly 170' is positioned in a reflow oven which exposes the thermoelectric sub-assembly 170' to a temperature equal to or in excess of the reflow temperature of the solder. In addition to or in lieu of a reflow oven, an infrared lamp could be used, for example. In any event, the thermoelectric sub-assembly 170' is permitted to cool and/or is actively cooled after it has been removed from the reflow oven.

[0039] Referring now to FIG. 4, a thermoelectric sub-assembly 270' comprises a hot-side substrate 172, a cold-side substrate, and thermoelectric elements 190 positioned intermediate the hot-side substrate 172 and the cold-side substrate. Each thermoelectric element 190 comprises a n-type thermoelectric leg 194 and a p-type thermoelectric leg 196. Each leg 194 and 196 comprises a bottom side 193 mounted to a metal pad 192 on the hot-side substrate 172. Each leg 194 and 196 further comprises lateral sides 195 and a top side 197. Each leg 194 and 196 is comprised of a thermoelectric material such as one or more of tetrahedrite, a skutterudite material, a half-Heusler alloy, lead telluride (PbTe), silicon-germanium (SiGe), a zinc antimonide, magnesium silicide stannide (Mg 2 (SiSn)), a magnesium silicide (Mg 2 Si), a HMS (higher manganese silicide) (MnSi), TAGS (tellurium- antimony-germanium-silver alloys), bismuth telluride (Bi 2 Te 3 ), zintl, and lanthanum telluride, for example.

[0040] In use, the thermoelectric materials of a thermoelectric system can oxidize and/or sublimate which can reduce the performance or efficiency of the

thermoelectric system. Such oxidation and/or sublimation is exacerbated when the thermoelectric materials are exposed to air and/or elevated temperatures. In various instances, the thermoelectric materials may be operated at a temperature of approximately 300 °C and/or in excess of 300 °C, for example. Moreover, the oxidation and/or sublimation of the thermoelectric material is a function of the exposed surface area of the thermoelectric material. More specifically, the oxidation and/or sublimation of the thermoelectric material is directly proportional to the surface area of the thermoelectric material that is exposed to the environment, or air, surrounding the thermoelectric material.

[0041] The legs 194 and 196 of the thermoelectric sub-assembly 270' are coated with coating 240 before the legs 194 and 196 are assembled to the hot-side substrate 172 and/or the cold-side substrate. The coating 240 reduces, if not eliminates, the exposed surface of the thermoelectric material which, in turn, reduces, if not eliminates, the oxidation and/or sublimation of the thermoelectric material. The coating 240 can also reduce, or eliminate, other forms of

environmental degradation. The legs 194 and 196 are entirely coated with the coating 240. In at least one such instance, the bottom side 193, the lateral sides 195 and the top side 197 of each leg 194 and 196 are entirely coated with the coating 240. Moreover, the edges defined between the bottom side 193, the lateral sides 195 and the top side 197 are coated with the coating 240. The coating 240 on the bottom surface 193 and/or the top surface 197 can prevent, or at least inhibit, the bonding material which bonds the legs 194 and 196 to the metal pads 192, for example, from migrating into the thermoelectric materials of the legs 194 and 196. In at least one such instance, the thermoelectric material does not directly contact the bonding material.

[0042] Each thermoelectric leg 194 and 196 has a substantially cubic shape, such as a rectangular cuboid shape, for example, comprising six sides and substantially right angles defined therebetween; however, the legs 194 and 196 can comprise any suitable configuration. The lateral sides 195 comprise four of the six sides and are each coated by the coating 240. Coating the lateral sides 195 with the coating 240, without more, reduces the exposed surface area of the thermoelectric material by about two-thirds. The bottom sides 193 of the legs 194 and 196 are bonded to the metal pads 192 and, as a result, the exposure of the bottom sides 193 to the surrounding environment is reduced or eliminated by the bonding material which couples the legs 194 and 196 to the metal pads 192. As such, the bottom sides 193 may or may not be coated by the coating 240. Similarly, the top sides 197 of the legs 194 and 196 are bonded to a cold-side substrate and may or may not be coated with the coating 240.

[0043] The coating 240 can be applied to the thermoelectric legs 194 and 196 in any suitable manner prior to mounting the legs 194 and 196 to a substrate. The coating 240 can be applied using a spray coating process, a dip coating process, an atomic layer deposition coating process, and/or a capillary flow coating process, for example. In at least one instance, the coating 240 is applied using a spray gun. Depending on the coating that is used, the coating 240 may need to be cured. In at least one instance, the coating 240 is dried and/or cured in a temperature range of approximately 90°-230°C for at least an hour, for example. That said, any suitable temperatures and times can be used to dry and/or cure the coating. Depending on the process that is used to apply the coating 240, all or less than all of the sides 193, 195, and 197 may be coated. To the extent that it is not desired for one or more of the sides 193, 195, and 197 to be coated, the sides can be masked during the coating process, for example. In at least one instance, the bottom side 193 and the top side 197 are uncoated. In various instances, the coating can be removed from one or more of the sides before and/or after the curing process. In at least one such instance, a grinding process can be used.

[0044] Further to the above, the thickness of the coating 240 can also affect the rate in which the thermoelectric materials oxidize and/or sublimate. In general, a thicker coating 240 reduces the rate in which the thermoelectric material oxidizes and/or sublimates as compared to a thinner coating. The coating 240 comprises a thickness in the range of approximately 25-50 μιη, for example; however, any suitable thickness can be used. For instance, the thickness of the coating 240 can be as low as 1 micron, for example. In other instances, the thickness of the coating 240 can be as low as 0.1 micron, for example. In at least one instance, the coating 240 comprises a thickness in the range of approximately 25-100 μιη, for example. In various instances, more than one layer of the coating 240 can be applied. In certain instances, more than one type of coating can be applied. For instance, the coating 240 can comprise an initial coating on the legs 194 and 196 and a different coating can then be applied on top of the coating 240, for example.

[0045] The above being said, the coating 240 can create a thermal short which reduces the efficiency of the thermoelectric sub-assembly 270'. That point notwithstanding, the coating 240 prevents high thermal resistances or thermal opens from developing within the thermoelectric materials over the life of the thermoelectric sub-assembly 270'. As the reader should appreciate, such high thermal resistances or opens can substantially reduce the efficiency of the thermoelectric sub-assembly 270' and/or render it inoperable.

[0046] All of the thermoelectric legs 194 and 196 of the thermoelectric subassembly 270' are coated, or at least partially coated, with the coating 240 and/or any suitable coating. In various alternative embodiments, only some of the thermoelectric legs 194 and 196 of the sub-assembly 270' are coated. In at least one such embodiment, the legs 194 and 196 of the thermoelectric elements 190 positioned around the outer perimeter of the thermoelectric sub-assembly 270' are at least partially coated with the coating 240 while the legs 194 and 196 of the inner thermoelectric elements 190, i.e., those positioned within the outer perimeter of thermoelectric elements 190, are not coated. The thermoelectric elements 190 positioned around the outer perimeter of the thermoelectric sub-assembly 270' may be more exposed to air than the inner elements 190. In another embodiment, the legs 194 and 196 of the thermoelectric elements 190 positioned around the outer perimeter of the thermoelectric sub-assembly 270' have a thicker coating than the legs 194 and 196 of the inner thermoelectric elements 190.

[0047] In certain embodiments, the thermoelectric elements 190 that are exposed to higher temperatures may be at least partially coated with the coating 240 while the elements 190 that are exposed to lower temperatures may not be coated. In at least one embodiment, the thermoelectric elements 190 that are exposed to higher temperatures may have a thicker coating than the elements 190 that are exposed to lower temperatures. In various instances, the elements 190 in the middle of a thermoelectric element array may be hotter than the elements 190 around the outer perimeter of the array.

[0048] In various embodiments, the n-type legs 194 are coated while the p-type legs 196 are not coated. In alternative embodiments, the p-type legs 196 are coated while the n-type legs 194 are not coated. In certain embodiments, the n-type legs 194 are coated with a first coating and the p-type legs 196 are coated with a second, or different, coating.

[0049] Further to the above, the coating material 240 can comprise an additive configured to reduce the oxidation and/or sublimation of the thermoelectric material. In various instances, the additive comprises at least one transition metal oxide, for example. In at least one instance, the additive comprises an antimony oxide (Sb x O y ) such as one or more of diantimony tetroxide (Sb 2 0 4 ), antimony trioxide (Sb 2 0 3 ), antimony pentoxide (Sb 2 0 5 ), antimony hexitatridecoxide (Sb 6 0i 3 ), and stibiconite (Sb 3 )06(OH), for example. In various instances, the coating 240 can have an ultrahigh loading of inorganic additives, such as silica and titania, for example. In at least one instance, the loading is between about 20%-90% by weight, for example. In certain instances, the loading is at least 15% by weight, for example. In at least one instance, the loading is up to 95% by weight, for example. Other additives can be used which can prevent any form of unwanted environmental degradation.

[0050] A method for manufacturing a thermoelectric assembly is depicted in the flowchart of FIG. 4A. The method comprises the step 201 of obtaining a plurality of thermoelectric elements, such as elements 190, for example, comprising a thermoelectric material and then at least partially coating the thermoelectric elements 190 with a coating 240, for example, as represented by step 202. The method of FIG. 4A further comprises the step 203 of then assembling the coated thermoelectric elements 190 onto a substrate, such as the hot-side substrate 172, for example. In at least one instance, the coated elements 190 are mounted to electrical connectors, such as metal pads 192, for example, on the substrate 172 using a bonding material, such as solder, for example. The method of FIG. 4A further comprises the step 204 of assembling a cold-side substrate to the thermoelectric elements 190.

[0051] FIG. 8A depicts a cross-section of a thermoelectric leg 196 having a coating 240 applied thereto in a manner described herein. The leg 196 was baked for about 99 hours at about 400 °C before it was cross-sectioned. As can be seen in FIG. 8A, the coating 240 has penetrated the thermoelectric material of the leg 196 to form an interfacial layer 240'. The interfacial layer 240' provides a self-limiting layer between the thermoelectric material and the coating 240. FIG. 8B depicts the thermoelectric leg 196 after it has been subjected to another 50 hours at about 400 °C. As the reader can see, the interfacial layer 240' is still present.

[0052] FIG. 9A depicts a cross-section of a thermoelectric leg 196 having a coating 240 applied thereto in a manner described herein. The leg 196 was baked for about 123 hours at about 400 °C before it was cross-sectioned. As can be seen in FIG. 9A, the coating 240 has penetrated the thermoelectric material of the leg 196 to form an interfacial layer 240'. The interfacial layer 240' provides a self-limiting layer between the thermoelectric material and the coating 240. FIG. 9B depicts the thermoelectric leg 196 after it has been subjected to another 50 hours at about 400 °C. As the reader can see, the interfacial layer 240' is still present.

[0053] Turning now to FIGS. 5A and 5B, a thermoelectric sub-assembly 370' comprises a hot-side substrate 172, a cold-side substrate, and thermoelectric elements 190 positioned intermediate the hot-side substrate 172 and the cold-side substrate. Each thermoelectric element 190 comprises a n-type thermoelectric leg 194 and a p-type thermoelectric leg 196. Each leg 194 and 196 comprises a bottom side 193 mounted to a metal pad 192 on the hot-side substrate 172. Each leg 194 and 196 further comprises lateral sides 195 and a top side 197. The thermoelectric elements 190 and the hot-side substrate 172 comprise a sub-assembly that is at least partially coated with a coating 340, for example, after the elements 190 have been bonded to the hot-side substrate 172, as illustrated in FIG. 5B.

[0054] In various instances, the coating 340 is dispensed onto the sub-assembly of FIG. 5A and is then permitted to flow downwardly over the legs 194 and 196 toward the substrate 172 to form sub-assembly 370'. In various instances, the coating 340 is dispensed onto the top sides 197 of the legs 194 and 196 and can flow

downwardly along the lateral sides 195 of the legs 194 and 196. In certain instances, the coating 340 can be dispensed along a path which includes the perimeter of the top sides 197 such that the coating 340 immediately flows down the lateral sides 195. In certain instances, the coating 340 is dispensed directly onto the hot-side substrate 172 and then at least partially wicks, via capillary action, up the sides of the metal pads 192, the legs 194 and 196, and/or the bonding material which bonds the legs 194 and 196 to the metal pads 192.

[0055] Further to the above, the coating 340 can flow onto the hot-side substrate 172. Moreover, the coating 340 can flow onto the metal pads 192 and/or the bonding material which bonds the legs 194 and 196 to the metal pads 192, for example. As the reader should appreciate, only a portion of the metal pads 192 and/or the bonding material may be exposed owing to the legs 194 and 196 being bonded thereto. As such, the edges, or perimeter, of the metal pads 192 and/or the edges, or perimeter, of the bonding material may be coated by the coating 340.

[0056] The coating 340 comprises a high-temperature stable organic polymer. A high-temperature stable organic polymer may comprise an epoxy polymer, for example. In various instances, the coating 340 may comprise a silicone material, such as, for example, Aremco's Corr-Paint™ CP40xx-S1 series solvent-based silicone resin, available from Aremco Products, Inc., Valley Cottage, New York, USA. A silicone resin may be characterized by branched, cage-like oligosiloxanes, and when dried and cured can form crosslinked and insoluble polysiloxanes. These materials have a sufficient viscosity to flow over the thermoelectric legs 194 and 196 at room, or ambient, temperature and/or at an elevated temperature and,

concurrently, sufficiently adhere to the legs 194 and 196 to form a coating thereon. In any event, the coating 340 is configured to reduce, or eliminate, the oxidation and/or sublimation of the thermoelectric materials comprising the thermoelectric legs 194 and 196. The coating 340 can also reduce, or eliminate, other forms of environmental degradation.

[0057] The coating 340 is applied to the thermoelectric legs 194 and 196 utilizing a capillary flow coating process; however, any suitable process can be used. During the capillary flow coating process, the coating 340 is heated to a temperature of approximately 90°-1 10°C and then dispensed over the legs 194 and 196 as discussed above. Dispensing the coating material 340 in this temperature range can be referred to as hot dispensing. A hot dispense method in a capillary flow process can provide a uniform coating on the thermoelectric legs 194 and 196 and provide sufficient wetting of the coating to the legs 194 and 196, for example. That said, the coating 340 can be dispensed at any suitable temperature, such as room or ambient temperature, for example.

[0058] Further to the above, thermoelectric materials often comprise crevices defined therein. Such crevices can increase the surface area of the thermoelectric legs that is exposed to the environment. The coating 340 enters the crevices during the capillary flow coating process. More specifically, the coating 340 flows into and is retained within the crevices via capillary action as the coating material is flowing over the thermoelectric legs 194 and 196. The capillary flow coating process can be performed at atmospheric pressure. In various other instances, the capillary coating process can be performed at a pressure above atmospheric pressure to increase the penetration of the coating into the thermoelectric material.

[0059] Further to the above, the thickness of the coating 340 can affect the rate in which the thermoelectric materials oxidize and/or sublimate. In general, the rate in which the thermoelectric material oxidizes and/or sublimates is slower for thicker coatings as compared to thinner coatings. The coating 340 comprises a thickness in the range of approximately 25-100 μιη, for example; however, any suitable thickness can be used. In various instances, more than one layer of the coating 340 can be applied. In certain instances, more than one type of coating can be applied. For instance, the coating 340 can comprise an initial coating on the legs 194 and 196 and a different coating can then be applied on top of the coating 340.

[0060] A capillary flow process can utilize gravity to pull the coating 340 down over the sides 195 of the thermoelectric legs 194 and 196 and onto the hot-side substrate 172. Certain processes can cause the coating 340 to flow from the hot-side substrate 172 onto the legs 194 and 196. In either event, the coating 340 can be thinner near the top side 197 of the legs 194 and 196 as compared to the bottom side 193. In such instances, the coating 340 will be thicker near the hot-side substrate 172, where the temperature is hotter, than the cold-side substrate, where the temperature is cooler. As a result, the thicker portion of the coating 340 is aligned with the regions of the thermoelectric material that are most likely to oxidize and/or sublimate and, as such, the rate in which the thermoelectric material oxidizes and/or sublimates can be reduced.

[0061] In at least one embodiment, further to the above, the coating 340 may not be present on the top sides 197 of the legs 194 and 196 and/or on the portions of the sides 195 adjacent the top sides 197. Advantageously, in such instances, the coating 340 may not act as a thermal short to the thermoelectric material of the legs 194 and 196 between the hot side and the cold side of the thermoelectric subassembly 370'.

[0062] All of the thermoelectric legs 194 and 196 of the thermoelectric subassembly 370' are coated, or at least partially coated, with the coating 340 and/or any suitable coating. In various alternative embodiments, only some of the thermoelectric legs 194 and 196 are coated. In at least one such embodiment, referring to FIG. 2, the legs 194 and 196 of the thermoelectric elements 190 positioned around the outer perimeter of the thermoelectric sub-assembly 370' are at least partially coated with the coating 340 while the legs 194 and 196 of the inner thermoelectric elements 190, i.e., those positioned within the outer perimeter of elements 190, are not coated, for example. The thermoelectric elements 190 positioned around the outer perimeter of the thermoelectric sub-assembly 370' may be more exposed to air than the inner elements 190 and, thus, more subject to oxidation, for instance. In another embodiment, the legs 194 and 196 of the thermoelectric elements 190 positioned around the outer perimeter of the thermoelectric sub-assembly 370' have a thicker coating than the coating on the legs 194 and 196 of the inner thermoelectric elements 190.

[0063] In certain embodiments, the thermoelectric elements 190 that are exposed to higher temperatures, and thus more subject to sublimation, may be at least partially coated while the elements 190 that are exposed to lower temperatures may not be coated. In at least one embodiment, the thermoelectric elements 190 that are exposed to higher temperatures may have a thicker coating than the coating of the elements 190 that are exposed to lower temperatures. In various instances, the elements 190 in the middle of a thermoelectric element array may be hotter than the elements 190 around the outer perimeter of the array.

[0064] Further to the above, the coating 340 may comprise one or more additives. In at least one instance, the coating 340 further comprises inorganic additives, for example. The inorganic additives may comprise a transition metal oxide, for example, and the transition metal oxide may comprise one or more of alumina, silica, titania, and zirconia, for example. An example of a coating 340 having an inorganic additive is Aremco's Corr-Paint™ CP40xx-S1 series solvent-based silicone resin discussed above, for example. In at least one instance, the additive comprises an antimony oxide (Sb x O y ) such as one or more of diantimony tetroxide (Sb 2 0 4 ), antimony trioxide (Sb 2 03), antimony pentoxide (Sb 2 05), antimony hexitatridecoxide (Sb 6 0i 3 ), and stibiconite (Sb 3 )0 6 (OH), for example. In various instances, the coating 440 can have an ultra-high loading of inorganic additives, such as silica and titania, for example. In at least one instance, the loading is between about 20%-90% by weight, for example. In certain instances, the loading is at least 15% by weight, for example. In at least one instance, the loading is up to 95% by weight, for example.

[0065] A method for manufacturing a thermoelectric assembly is depicted in the flowchart of FIG. 5C. The method comprises the step of obtaining a plurality of thermoelectric elements comprising a thermoelectric material, such as elements 190, for example, and assembling the thermoelectric elements 190 onto a substrate, such as the hot-side substrate 172, for example, as represented by step 301 . In at least one instance, the coated elements 190 are mounted to electrical connectors, such as metal pads 192, for example, on the substrate 172 using a bonding material, such as solder, for example. The method of FIG. 5C further comprises the step 302 of then at least partially coating the thermoelectric elements 190 with a coating 340, for example. The method of FIG. 5C further comprises the step 303 of assembling a cold-side substrate to the thermoelectric elements 190.

[0066] In various alternative embodiments, the thermoelectric legs 194 and 196 are bonded to a cold-side substrate to form a sub-assembly which is then coated. In such embodiments, the hot-side substrate can be bonded to the thermoelectric elements after the sub-assembly has been coated.

[0067] In various embodiments, further to the above, the thermoelectric legs of a sub-assembly can be at least partially coated with a first coating before they are assembled to a substrate. The sub-assembly can then be coated with a second coating. In various embodiments, the first coating is comprised of the same material as the second coating. In other embodiments, the first coating and the second coating are comprised of different materials. In certain embodiments, more than two coatings can be used. One or more coatings can be applied to the thermoelectric legs before they are bonded to a substrate and/or one or more coatings can be applied to the thermoelectric legs after they have been bonded to a substrate.

[0068] Turning now to FIGS. 6A and 6B, a thermoelectric sub-assembly 470' comprises a hot-side substrate 172, a cold-side substrate 179, and thermoelectric elements 190 positioned intermediate the hot-side substrate 172 and the cold-side substrate 179. Each thermoelectric element 190 comprises a n-type thermoelectric leg 194 and a p-type thermoelectric leg 196. Each leg 194 and 196 comprises a bottom side 193 bonded to a metal pad 192 on the hot-side substrate 172 and a top side 197 bonded to an electrical connector 199 defined on the cold-side substrate 173. Each leg 194 and 196 further comprises lateral sides 195 defined between the bottom side 193 and the top side 197 thereof.

[0069] The thermoelectric elements 190, the hot-side substrate 172, and the cold- side substrate 179 comprise a sub-assembly that is at least partially coated or filled with a coating 440, for example, as illustrated in FIG. 6B. The coating 440 is dispensed into the subassembly of FIG. 6A and is permitted to flow in-between and around the thermoelectric legs 194 and 196. More specifically, the coating 440 is dispensed into the voids 198 defined between the hot-side substrate 172, the cold- side substrate 179, and the thermoelectric legs 194 and 196 in order to at least partially coat the legs 194 and 196. The coating 440 also at least partially coats the hot-side substrate 172, the cold-side substrate 179, and the electrical

interconnections between the thermoelectric legs 194 and 196 and an electrical circuit defined on the substrates 172 and 179. The coating 440 completely fills the voids 198; however, the reader should understand that some of the voids 198 may not be filled or completely filled.

[0070] Similar to the above, the coating 440 can flow onto the metal pads 192 and/or the bonding material which bonds the legs 194 and 196 to the metal pads 192, for example. As the reader should appreciate, only a portion of the metal pads 192 and/or the bonding material may be exposed owing to the legs 194 and 196 being bonded thereto. As such, the edges, or perimeter, of the metal pads 192 and/or the edges, or perimeter, of the bonding material may be coated by the coating 440.

[0071] The coating 440 comprises a high-temperature stable organic polymer. A high-temperature stable organic polymer may comprise an epoxy polymer, for example. In various instances, the coating 440 may comprise a silicone material, such as, for example, Aremco's Corr-Paint™ CP40xx-S1 series solvent-based silicone resin, available from Aremco Products, Inc., Valley Cottage, New York, USA. A silicone resin may be characterized by branched, cage-like oligosiloxanes, and when dried and cured can form crosslinked and insoluble polysiloxanes. These materials have a sufficient viscosity to flow over the thermoelectric legs 194 and 196 at room, or ambient, temperature and/or at an elevated temperature and,

concurrently, sufficiently adhere to the legs 194 and 196 to form a coating thereon. The coating 440 increases the diffusion path of oxygen from the ambient

environment to the thermoelectric legs 194 and 196 and, as a result, reduces, or eliminates, the oxidation and/or sublimation of the thermoelectric materials comprising the thermoelectric legs 194 and 196. The coating 440 can also reduce, or eliminate, other forms of environmental degradation. In various instances, the coating 440 seals, or at least substantially seals, the thermoelectric material from the ambient environment.

[0072] The coefficient of thermal expansion (CTE) of the material selected for the coating 440 can be selected so as to not induce unnecessary and/or unacceptable stresses within the thermoelectric legs 194 and 196, the substrates 172 and 179, and/or the interconnections between the legs 194 and 196 and the substrates 172 and 179. In various instances, the coating material is selected such that the CTE of the coating material is within the range of coefficients of thermal expansion of the other materials comprising the thermoelectric sub-assembly 470'. In certain instances, the coating material is selected such that the CTE of the coating material is lower than the coefficients of thermal expansion of the other materials comprising the thermoelectric sub-assembly 470'. In at least one instance, the CTE of the coating 440 is within a range between about 10% larger than and about 10% smaller than the CTE of the thermoelectric material of the legs 194 and 196, for example.

[0073] The coating 440 is inserted into the thermoelectric sub-assembly 470' utilizing a capillary flow process; however, any suitable process can be used. During the capillary flow coating process, the coating 440 is heated to a temperature of approximately 90°-1 10°C and then dispensed into the thermoelectric sub-assembly 470' as discussed above. That said, the coating 440 can be dispensed at any suitable temperature, such as room or ambient temperature, for example.

Thereafter, the thermoelectric sub-assembly 470' can be actively cooled and/or allowed to cool. In at least one instance, the coating 440 can be dispensed into the thermoelectric sub-assembly 470' and then heated within the thermoelectric subassembly 470' to temporarily decrease the viscosity of the coating 440. In such instances, the heated coating 440 can readily flow around the legs 194 and 196 and fill the voids therebetween. Such an approach can reduce the possibility of air pockets being trapped within the coating 440. In various instances, the coating 440 can be inserted into the thermoelectric sub-assembly 470' utilizing a potting process where the coating 440 is poured into the thermoelectric sub-assembly 470' and then cured.

[0074] Further to the above, the density of the coating 440 can affect the rate in which the thermoelectric materials oxidize and/or sublimate. In general, the rate in which the thermoelectric material oxidizes and/or sublimates is slower for denser coatings as compared to less dense coatings. Correspondingly, the rate in which the thermoelectric material oxidizes and/or sublimates is faster for less dense coatings as compared to denser coatings.

[0075] Further to the above, the thermoelectric sub-assembly 470' is entirely filled with the coating 440. In such instances, all of the thermoelectric legs 194 and 196 of the thermoelectric sub-assembly 470' are coated with the coating 440 and/or any suitable coating. In various alternative embodiments, only some of the

thermoelectric legs 194 and 196 are coated. In at least one such embodiment, referring to FIGS. 7A and 7B, the legs 194 and 196 of the thermoelectric elements 190 positioned around the outer perimeter of a thermoelectric sub-assembly 570' are at least partially coated with the coating 440 while the legs 194 and 196 of the inner thermoelectric elements 190, i.e., those positioned within the outer perimeter of elements 190, are not coated, for example. In such instances, the coating 440 surrounding the outer perimeter of the thermoelectric elements 190 can form a seal which reduces, or eliminates, the oxidation and/or sublimation of, at least, the inner thermoelectric elements 190. Such an arrangement can reduce or stop the permeation of oxygen into the thermoelectric sub-assembly 570' without substantially affecting the performance of the thermoelectric sub-assembly 570'. In at least one embodiment, the coating 440 is comprised of enamel, for example.

[0076] Further to the above, referring again to FIG. 7B, the coating 440 can create a sealed environment within the thermoelectric sub-assembly 570'. The sealed environment can include the voids 198 between the thermoelectric legs 194 and 196. The sealed environment is filled with an inert gas, such as nitrogen, argon, and/or helium, for example. In various instances, the sealed environment is filled with a suitable gas other than oxygen. In certain instances, the sealed environment has a pressure which is lower than atmospheric pressure. In at least one such instance, the sealed environment comprises a vacuum.

[0077] The coating 440 may comprise one or more additives. In at least one instance, the coating 440 further comprises inorganic additives, for example. The inorganic additives may comprise a transition metal oxide, for example, and the transition metal oxide may comprise one or more of alumina, silica, titania, and zirconia, for example. An example of a coating 440 having an inorganic additive is Aremco's Corr-Paint™ CP40xx-S1 series solvent-based silicone resin discussed above, for example. In at least one instance, the additive comprises an antimony oxide (Sb x Oy) such as one or more of diantimony tetroxide (Sb 2 0 4 ), antimony thoxide (Sb 2 03), antimony pentoxide (Sb 2 05), antimony hexitatridecoxide (Sb 6 0i 3), and stibiconite (Sb 3 )0 6 (OH), for example. In various instances, the coating 440 can have an ultra-high loading of inorganic additives, such as silica and titania, for example. In at least one instance, the loading is between about 20%-90% by weight, for example. In certain instances, the loading is at least 15% by weight, for example. In at least one instance, the loading is up to 95% by weight, for example.

[0078] A method for manufacturing a thermoelectric assembly is depicted in the flowchart of FIG. 6C. The method comprises the step of obtaining a plurality of thermoelectric elements comprising a thermoelectric material, such as elements 190, for example, and assembling the coated thermoelectric elements 190 onto a substrate, such as hot-side substrate 172, for example, as represented by step 401 . In at least one instance, the coated elements 190 are mounted to electrical connectors on the substrate 172 using a bonding material, such as solder, for example. The method of FIG. 6C further comprises the step of assembling a cold- side substrate to the thermoelectric elements 190. The method of FIG. 6C further comprises the step 402 of then at least partially filling the thermoelectric assembly with a coating 440, for example.

[0079] Various embodiments disclosed herein comprise mounting, or bonding, the thermoelectric legs of a plurality of thermoelectric elements to a hot-side substrate and then mounting, or bonding, a cold-side substrate to the thermoelectric elements. Such embodiments could also be implemented by mounting, or bonding, the thermoelectric elements to the cold-side substrate and then mounting, or bonding, the hot-side substrate to the thermoelectric elements.

[0080] In various embodiments, further to the above, the thermoelectric legs of a sub-assembly can be at least partially coated with a first coating before they are assembled to a first substrate. A second substrate can then be assembled to the thermoelectric legs. The sub-assembly can then be coated or filled with a second coating. In various embodiments, the first coating is comprised of the same material as the second coating. In other embodiments, the first coating and the second coating are comprised of different materials.

[0081] In various embodiments, further to the above, the thermoelectric legs of a sub-assembly can be coated using a first coating process and then coated using a second, or different, coating process. In at least one instance, a first coating is applied to the thermoelectric legs using a spray coating process and then a second coating is applied to the legs using a capillary coating process, for example.

[0082] The metal pads 192, the electrical interconnections between the

thermoelectric legs and the electrical circuits defined on the hot-side substrate and cold-side substrate, and/or the bonding materials used to create the electrical interconnections can be comprised of any suitable material, such as copper, silver, molybdenum, and/or copper-molybdenum alloys, for example.

[0083] The thermoelectric systems disclosed herein can be adapted for use with automotive systems. Certain automotive systems comprise a propulsion system including an internal combustion engine which generates exhaust heat. One or more of the thermoelectric systems disclosed herein can be adapted to reclaim that exhaust heat. In at least one instance, a thermoelectric system is mounted to and/or downstream of a catalytic converter which treats the exhaust stream from the internal combustion engine. The thermoelectric system can be mounted within the catalytic converter and/or to an exterior housing of the catalytic converter, for example. In certain instances, the thermoelectric system can be embedded within the exterior housing of the catalytic converter. In various instances, a voltage potential generated by a catalytic converter thermoelectric system can be used to power one or more sensor systems configured to evaluate the exhaust passing through the catalytic converter, for example.

[0084] Further to the above, heat generated by an internal combustion engine is often discharged to the surrounding environment through an air-cooled heat exchanger via a fluidic thermodynamic circuit. One or more of the thermoelectric systems disclosed herein can be adapted to reclaim that discharged heat. In at least one instance, a thermoelectric system is mounted to a heat exchanger, or radiator, of the fluidic thermodynamic circuit which cools the fluid flowing through the circuit. In various instances, a voltage potential generated by a radiator thermoelectric system can be used to power one or more sensor systems configured to evaluate the fluid passing through the radiator, for example. In various instances, a thermoelectric system can be mounted to any suitable portion of the fluidic thermodynamic circuit and/or mounted directly to the block of the internal combustion engine, for example. In at least one instance, further to the above, a thermoelectric system can be mounted to an exhaust manifold which connects the exhaust system to the engine block, for example.

[0085] The entire disclosures of the following patents are incorporated by reference herein:

- U.S. Patent No. 8,603,940, entitled AUTOMOBILE EXHAUST GAS CATALYTIC CONVERTER, which issued on December 10, 2013;

- U.S. Patent No. 8,650,864, entitled COMBINATION LIQUID-COOLED EXHAUST MANIFOLD ASSEMBLY AND CATALYTIC CONVERTER ASSEMBLY FOR A MARINE ENGINE, which issued on February 18, 2014;

- U.S. Patent No. 8,544,257, entitled ELECTRICALLY STIMULATED CATALYTIC CONVERTER APPARATUS, AND METHOD OF USING SAME, which issued on October 1 , 2013; - U.S. Patent No. 7,858,052, entitled CATALYTIC CONVERTER OPTIMIZATION, which issued on December 28, 2010;

- U.S. Patent No. 7,767,622, entitled CATALYTIC CONVERTER WITH IMPROVED START-UP BEHAVIOR, which issued on August 3, 2010;

- U.S. Patent No. 7,051 ,522, entitled THERMOELECTRIC CATALYTIC

CONVERTER TEMPERATURE CONTROL, which issued on May 30, 2006;

- U.S. Patent No. 9,276, 188, entitled THERMOELECTRIC-BASED POWER

GENERATION SYSTEMS AND METHODS, which issued on March 1 , 2016;

- U.S. Patent No. 9,006,556, entitled THERMOELECTRIC POWER GENERATOR FOR VARIABLE THERMAL POWER SOURCE, which issued on April 14, 2015;

- U.S. Patent No. 8,646,261 , entitled THERMOELECTRIC GENERATORS

INCORPORATING PHASE-CHANGE MATERIALS FOR WASTE HEAT

RECOVERY FROM ENGINE EXHAUST, which issued on February 1 1 , 2014;

- U.S. Patent No. 6,986,247, entitled THERMOELECTRIC CATALYTIC POWER GENERATOR WITH PREHEAT, which issued on January 17, 2006; and

- U.S. Patent No. 4,029,472, entitled THERMOELECTRIC EXHAUST GAS

SENSOR, which issued on June 14, 1977.

[0086] Certain automotive systems, further to the above, comprise a propulsion system including an electric motor powered by one or more batteries. In use, the batteries can generate a significant amount of thermal energy owing to high power demands from the electric motor. Similarly, the electric motor can generate a significant amount of thermal energy during use. Such thermal energy can be harvested and reclaimed by one or more of the thermoelectric systems disclosed herein. In various instances, a battery comprises one or more battery cells positioned within an outer housing. The battery cells comprise lithium-ion battery cells, for example. In use, the heat generated by the battery cells radiates through the outer housing of the battery. In certain instances, the thermoelectric elements of a thermoelectric system are mounted to the outer housing of the battery. In various instances, the thermoelectric elements of a thermoelectric system are positioned intermediate two battery cells.

[0087] In addition to or in lieu of the above, a thermoelectric system disclosed herein can be used to cool a battery, for example. In such instances, the

thermoelectric system is operated as a Peltier device. In at least one such instance, the thermoelectric elements of the thermoelectric system are positioned on, at, and/or near the hottest portions of the battery, for example, to prevent, or at least reduce the possibility of the battery entering into a thermal runaway condition.

[0088] The entire disclosures of the following patents are incorporated by reference herein:

- U.S. Patent No. 7,781 ,097, entitled CELL THERMAL RUNAWAY PROPAGATION RESISTANCE USING AN INTERNAL LAYER OF INTUMESCENT MATERIAL, which issued on August 24, 2010;

- U.S. Patent No. 7,763,381 , entitled CELL THERMAL RUNAWAY PROPAGATION RESISTANCE USING DUAL INTUMESCENT MATERIAL LAYERS, which issued on July 27, 2010;

- U.S. Patent No. 7,736,799, entitled METHOD AND APPARATUS FOR

MAINTAINING CELL WALL INTEGRITY DURING THERMAL RUNAWAY USING AN OUTER LAYER OF INTUMESCENT MATERIAL, which issued on June 15, 2010;

- U.S. Patent No. 8, 168,315, entitled METHOD FOR DETECTING BATTERY THERMAL EVENTS VIA BATTERY PACK ISOLATION MONITORING, which issued on May 1 , 2012;

- U.S. Patent No. 8, 154,256, entitled BATTERY THERMAL EVENT DETECTION SYSTEM USING AN ELECTRICAL CONDUCTOR WITH A THERMALLY INTERRUPTIBLE INSULATOR, which issued on April 10, 2012;

- U.S. Patent No. 8, 153,290, entitled HEAT DISSIPATION FOR LARGE BATTERY PACKS, which issued on April 10, 2012;

- U.S. Patent No. 8, 1 17,857, entitled INTELLIGENT TEMPERATURE CONTROL SYSTEM FOR EXTENDING BATTERY PACK LIFE, which issued on February 21 , 2012;

- U.S. Patent No. 8,082,743 , entitled BATTERY PACK TEMPERATURE

OPTIMIZATION CONTROL SYSTEM, which issued on December 27, 201 1 ;

- U.S. Patent No. 8,092,081 , entitled BATTERY THERMAL EVENT DETECTION SYSTEM USING AN OPTICAL FIBER, which issued on January 10, 2012;

- U.S. Patent No. 8,059,007, entitled BATTERY THERMAL EVENT DETECTION SYSTEM USING A THERMALLY INTERRUPTIBLE ELECTRICAL CONDUCTOR, which issued on November 15, 201 1 ; - U.S. Patent No. 7,940,028, entitled THERMAL ENERGY TRANSFER SYSTEM FOR A POWER SOURCE UTILIZING BOTH METAL-AIR AND NON-METAL-AIR BATTERY PACKS, which issued on May 10, 201 1 ;

- U.S. Patent No. 7,939, 192, entitled EARLY DETECTION OF BATTERY CELL THERMAL EVENT, which issued on May 10, 201 1 ;

- U.S. Patent No. 7,820,319, entitled CELL THERMAL RUNAWAY PROPAGATION RESISTANT BATTERY PACK, which issued on October 26, 2010;

- U.S. Patent No. 7,789, 176, entitled ELECTRIC VEHICLE THERMAL

MANAGEMENT SYSTEM, which issued on September 7, 2010;

- U.S. Patent No. 8, 178,227, entitled METHOD FOR DETECTING BATTERY THERMAL EVENTS VIA BATTERY PACK ISOLATION RESISTANCE MONITORI NG, which issued on May 15, 2012;

- U.S. Patent No. 8, 168,315, entitled METHOD FOR DETECTING BATTERY THERMAL EVENTS VIA BATTERY PACK ISOLATION MONITORING, which issued on May 1 , 2012;

- U.S. Patent No. 7,890,218, entitled CENTRALIZED MULTI-ZONE COOLING FOR INCREASED BATTERY EFFICIENCY, which issued on February 15, 201 1 ;

- U.S. Patent No. 8,481 , 191 , entitled RIGID CELL SEPARATOR FOR MINIMIZING THERMAL RUNAWAY PROPAGATION WITHI N A BATTERY PACK, which issued on July 9, 2013;

- U.S. Patent No. 8,402,776, entitled THERMAL MANAGEMENT SYSTEM WITH DUAL MODE COOLANT LOOPS, which issued on March 26, 2013;

- U.S. Patent No. 8,367,233, entitled BATTERY PACK ENCLOSURE WITH

CONTROLLED THERMAL RUNAWAY RELEASE SYSTEM, which issued on February 5, 2013;

- U.S. Patent No. 8,313,850, entitled METHOD FOR DETECTING BATTERY THERMAL EVENTS VIA BATTERY PACK PRESSURE MONITORING, which issued on November 20, 2012;

- U.S. Patent No. 8,263,250, entitled LIQUID COOLING MANIFOLD WITH MULTIFUNCTION THERMAL INTERFACE, which issued on September 1 1 , 2012;

- U.S. Patent No. 8,541 , 127, entitled OVERMOLDED THERMAL INTERFACE FOR USE WITH A BATTERY COOLING SYSTEM, which issued on September 24, 2013;

- U.S. Patent No. 8,968,949, entitled METHOD OF WITHDRAWING HEAT FROM A BATTERY PACK, which issued on March 3, 2015; - U.S. Patent No. 8,907,594, entitled COOLING SYSTEMS AND METHODS, which issued on December 9, 2014;

- U.S. Patent No. 8,906,541 , entitled BATTERY MODULE WITH INTEGRATED THERMAL MANAGEMENT SYSTEM, which issued on December 9, 2014;

- U.S. Patent No. 8,899,492, entitled METHOD OF CONTROLLING SYSTEM TEMPERATURE TO EXTEND BATTERY PACK LIFE, which issued on December 2, 2014;

- U.S. Patent No. 8,875,828, entitled VEHICLE BATTERY PACK THERMAL

BARRIER, which issued on November 4, 2014;

- U.S. Patent No. 8,758,924, entitled EXTRUDED AND RIBBED THERMAL

INTERFACE FOR USE WITH A BATTERY COOLI NG SYSTEM, which issued on June 24, 2014;

- U.S. Patent No. 9,093,726, entitled ACTIVE THERMAL RUNAWAY MITIGATION SYSTEM FOR USE WITHIN A BATTERY PACK, which issued on July 28, 2015; and

- U.S. Patent No. 9,030,063, entitled THERMAL MANAGEMENT SYSTEM FOR USE WITH AN INTEGRATED MOTOR ASSEMBLY, which issued on May 12, 2015.

[0089] The entire disclosures of the following patents are incorporated by reference herein:

- U.S. Patent No. 9,306, 143, entitled HIGH EFFICIENCY THERMOELECTRIC GENERATION, which issued on April 5, 2016;

- U.S. Patent No. 9,293,680, entitled CARTRIDGE-BASED THERMOELECTRIC SYSTEMS, which issued on March 22, 2016; and

- U.S. Patent No. 9,276, 188, entitled THERMOELECTRIC-BASED POWER

GENERATION SYSTEMS AND METHODS, which issued on March 1 , 2016.

[0090] The entire disclosures of the following patent applications are incorporated by reference herein:

- U.S. Patent Application Publication No. 2014/0190185, entitled SYSTEM AND METHOD FOR PREVENTING OVERHEATING OR EXCESSIVE BACKPRESSURE IN THERMOELECTRIC SYSTEMS, which published on July 10, 2014;

- U.S. Patent Application Publication No. 2013/0276849, entitled TEG-POWERED COOLING CIRCUIT FOR THERMOELECTRIC GENERATOR, which published on October 24, 2013; and - U.S. Patent Application Publication No. 2013/0255739, entitled PASSIVELY COOLED THERMOELECTRIC GENERATOR CARTRIDGE, which published on October 3, 2013.

[0091] The Applicant of the present application also owns the patents and patent applications identified below, the entire disclosures of which are incorporated by reference herein:

- U.S. Patent Application Serial No.1 1/645,236, entitled METHODS OF

FABRICATING NANOSTRUCTURES AND NANOWIRES AND DEVICES FABRICATED THEREFROM, now U.S. Patent No. 7,834,264;

- U.S. Patent Application Serial No. 12/487,893, entitled IMPROVED MECHANICAL STRENGTH & THERMOELECTRIC PERFORMANCE IN METAL CHALCOGENIDE MQ (M=GE,SN,PB AND Q=S, SE, TE) BASED COMPOSITIONS, now U.S. Patent No. 8,277,677;

- U.S. Patent Application Serial No. 12/882,580, entitled THERMOELECTRICS COMPOSITIONS COMPRISING NANOSCALE INCLUSIONS IN A CHALCOGENIDE MATRIX, now U.S. Patent No. 8,778,214;

- U.S. Patent Application Serial No. 12/943, 134, entitled UNI WAFER

THERMOELECTRIC MODULES, now U.S. Patent Application Publication No.

201 1 /01 14146;

- U.S. Patent Application Serial No. 13/299, 179, entitled ARRAYS OF LONG NANOSTRUCTURES IN SEMICONDUCTOR MATERIALS AND METHODS THEREOF, now U.S. Patent No. 9,240,328;

- U.S. Patent Application Serial No. 13/308,945, entitled LOW THERMAL

CONDUCTIVITY MATRICES WITH EMBEDDED NANOSTRUCTURES AND METHODS THEREOF, now U.S. Patent No. 8,736,01 1 ;

- U.S. Patent Application Serial No. 13/331 ,768, entitled ARRAYS OF FILLED NANOSTRUCTURES WITH PROTRUDING SEGMENTS AND METHODS THEREOF, now U.S. Patent Application Publication No. 2012/0152295;

- U.S. Patent Application Serial No. 13/364, 176, entitled ELECTRODE

STRUCTURES FOR ARRAYS OF NANOSTRUCTURES AND METHODS THEREOF, now U.S. Patent Application Publication No. 2012/0247527;

- U.S. Patent Application Serial No. 13/749,470, entitled MODULAR

THERMOELECTRIC UNITS FOR HEAT RECOVERY SYSTEMS AND METHODS THEREOF, now U.S. Patent No. 9,318,682; - U.S. Patent Application Serial No. 13/760,977, entitled BULK NANOHOLE

STRUCTURES FOR THERMOELECTRIC DEVICES AND METHODS FOR MAKING THE SAME, now U.S. Patent Application Publication No. 2013/0175654;

- U.S. Patent Application Serial No. 13/786,090, entitled BULK NANO-RIBBON AND/OR NANO-POROUS STRUCTURES FOR THERMOELECTRIC DEVICES AND METHODS FOR MAKING THE SAME, now U.S. Patent No. 9,051 , 175;

- U.S. Patent Application Serial No. 13/947,400, entitled METHOD AND

STRUCTURE FOR THERMOELECTRIC UNICOUPLE ASSEMBLY, now U.S.

Patent No. 9,257,627;

- U.S. Patent Application Serial No. 14/053,452, entitled STRUCTURES AND METHODS FOR MULTI-LEG PACKAGE THERMOELECTRIC DEVICES, now U.S. Patent Application Publication No. 2014/0182644;

- U.S. Patent Application Serial No. 14/059,362, entitled NANOSTRUCTURED THERMOELECTRIC ELEMENTS AND METHODS OF MAKING THE SAME, now U.S. Patent No. 9,082,930;

- U.S. Patent Application Serial No. 14/062,803, entitled BULK-SIZE

NANOSTRUCTURED MATERIALS AND METHODS FOR MAKING THE SAME BY SINTERING NANOWIRES, now U.S. Patent Application Publication No.

2014/01 16491 ;

- U.S. Patent Application Serial No. 14/297,444, entitled SILICON-BASED

THERMOELECTRIC MATERIALS INCLUDING ISOELECTRONIC IMPURITIES, THERMOELECTRIC DEVICES BASED ON SUCH MATERIALS, AND METHODS OF MAKING AND USING SAME, now U.S. Patent Application Publication No.

2014/0360546;

- U.S. Patent Application Serial No. 14/469,404, entitled THERMOELECTRIC DEVICES HAVING REDUCED THERMAL STRESS AND CONTACT RESISTANCE, AND METHODS OF FORMING AND USING THE SAME, now U.S. Patent No.

9,065,017;

- U.S. Patent Application Serial No. 14/679,837, entitled FLEXIBLE LEAD FRAME FOR MULTI-LEG PACKAGE ASSEMBLY, now U.S. Patent Application Publication No. 2015/0287901 ;

- U.S. Patent Application Serial No. 14/682,471 , entitled ULTRA-LONG SILICON NANOSTRUCTURES, AND METHODS OF FORMING AND TRANSFERRING THE SAME, now U.S. Patent Application Publication No. 2016/0035829; - U.S. Patent Application Serial No. 14/686,641 , entitled MODULAR THERMOELECTRIC UNITS FOR HEAT RECOVERY SYSTEMS AND METHODS THEREOF, now U.S. Patent Application Publication No. 2015/0287902;

- U.S. Patent Application Serial No. 14/823,738, entitled TIN SELENIDE SI NGLE CRYSTALS FOR THERMOELECTRIC APPLICATIONS, now U.S. Patent

Application Publication No. 2016/0049568;

- U.S. Patent Application Serial No. 14/872,681 , entitled THERMOELECTRIC GENERATING UNIT AND METHODS OF MAKING AND USING SAME;

- U.S. Patent Application Serial No. 14/872,898, entitled THERMOELECTRIC GENERATORS FOR RECOVERING WASTE HEAT FROM ENGI NE EXHAUST, AND METHODS OF MAKING AND USING SAME, now U.S. Patent Application Publication No. 2016/0099398;

- U.S. Patent Application Serial No. 14/971 ,337, entitled ELECTRICAL AND THERMAL CONTACTS FOR BULK TETRAHEDRITE MATERIAL, AND METHODS OF MAKING THE SAME, now U.S. Patent Application Publication No.

2016/0190420;

- International Application Patent No. PCT/US2015/053434, entitled

THERMOELECTRIC GENERATING UNIT AND METHODS OF MAKING AND USING SAME, now WO Publication No. 2016/054333; and

- International Application Patent No. PCT/US2016/054791 , entitled MECHANICAL ADVANTAGE IN LOW TEMPERATURE BOND TO A SUBSTRATE IN A THERMOELECTRIC PACKAGE.

[0092] Although various devices have been described herein in connection with certain embodiments, modifications and variations to those embodiments may be implemented. Also, where materials are disclosed for certain components, other materials may be used. Furthermore, according to various embodiments, a single component may be replaced by multiple components, and multiple components may be replaced by a single component, to perform a given function or functions. The foregoing description and following claims are intended to cover all such

modifications and variations.

[0093] Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. Well- known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. The reader will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and illustrative. Variations and changes thereto may be made without departing from the scope of the claims.

[0094] The terms "comprise" (and any form of comprise, such as "comprises" and "comprising"), "have" (and any form of have, such as "has" and "having"), "include" (and any form of include, such as "includes" and "including") and "contain" (and any form of contain, such as "contains" and "containing") are open-ended linking verbs. As a result, a thermoelectric system, device, or apparatus that "comprises," "has," "includes" or "contains" one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements.

Likewise, an element of a system, device, or apparatus that "comprises," "has," "includes" or "contains" one or more features possesses those one or more features, but is not limited to possessing only those one or more features.

[0095] It is to be understood that certain descriptions of the embodiments described herein have been simplified to illustrate only those elements, features, and aspects that are relevant to a clear understanding of the disclosed embodiments, while eliminating, for purposes of clarity, other elements, features, and aspects. Persons having ordinary skill in the art, upon considering the present description of the disclosed embodiments, will recognize that other elements and/or features may be desirable in a particular implementation or application of the disclosed

embodiments. However, because such other elements and/or features may be readily ascertained and implemented by persons having ordinary skill in the art upon considering the present description of the disclosed embodiments, and are therefore not necessary for a complete understanding of the disclosed embodiments, a description of such elements and/or features is not provided herein. As such, it is to be understood that the description set forth herein is merely exemplary and illustrative of the disclosed embodiments and is not intended to limit the scope of the claims.

[0096] Also, any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Any maximum numerical limitation recited herein is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited herein is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicants reserve the right to amend the present disclosure, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited herein.

[0097] The grammatical articles "one", "a", "an", and "the", as used herein, are intended to include "at least one" or "one or more", unless otherwise indicated. Thus, the articles are used herein to refer to one or more than one (i.e., to at least one) of the grammatical objects of the article. By way of example, "a component" means one or more components, and thus, possibly, more than one component is contemplated and may be employed or used in an implementation of the described embodiments.

[0098] Any patent, publication, or other disclosure material that is said to be incorporated, in whole or in part, by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein is only incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0099] The present disclosure includes descriptions of various embodiments. It is to be understood that all embodiments described herein are exemplary, illustrative, and non-limiting.