CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to United States Provisional Patent Application, Serial No. 62/667,686, filed May 7, 2018, entitled HOLD-DOWN ASSEMBLY AND DEVICE FOR A BATTERY, and to United States Provisional Patent Application, Serial No. 62/599,418, filed December 15, 2017, entitled HOLD-DOWN ASSEMBLY AND DEVICE FOR A BATTERY, each of which is hereby incorporated by reference herein in its entirety.

FIELD

[0001] This disclosure relates to a hold-down device and assembly for securing one or more battery cells within a battery cell housing and, in particular, to a hold-down assembly that secures and stabilizes one or more battery cells within a battery cell housing while reducing gaps between the walls of the battery cell housing and the battery cells within.

BACKGROUND

[0002] When charging a rechargeable battery cell, the chemical reactions within the battery cell may cause an increase in temperature and swelling of the battery cell. For example, charge/discharge cycles may cause the side walls of a prismatic battery cell to bow or expand, which can reduce battery life.

[0003] Some currently known battery modules include a housing containing a plurality of prismatic battery cells therein. During assembly of the battery module, the prismatic battery cells are arranged within the housing such that the broad side walls of adjacent battery cells are next to each other. This may be referred to as a battery cell stack. A currently known battery cell stack 10 including a plurality of battery cells 12 within a battery cell housing 14 is shown in FIG. 1 (these collectively may be referred to as a battery module). The battery cell housing 14 must be designed (that is, sized and configured) to include a gap 16 between the battery cell stack 10 and at least one of the internal walls of the battery cell housing 14 for assembly. The size of the gap(s) 16 depends on such factors as the thickness of the individual battery cells 12 and/or of the stack 10 as a whole (which may depend, at least in part, on the temperature, aging, and/or shelf life of the battery cells 12, and may fluctuate over time with use), the internal dimensions of the battery cell housing 14 as molded, or the like.

[0004] To transfer heat produced by the battery cells 12 during operation and/or to reduce the gap(s) 16 between the battery cell stack 10 and the battery cell housing 14 and/or between adjacent battery cells 12, one or more thermal pads 18 may be used within the battery cell housing 14. However, when the gap(s) 16 are large, the thermal pad(s) 18 must be thicker, which can increase manufacturing cost and reduce thermal conductivity. Additionally, due to materials variation and battery cell height control issues, battery cells 12 often have non-uniform contact with the bottom of the inside of the battery cell housing 14, further reducing thermal exchange between the battery cells 12 and the thermal pad(s) 18.

[0005] Further, the battery cells 12 must be secured and stabilized within the battery cell housing 14 to prevent damage to the battery cells 12 by vibration, shock, and/or abrasion and to maintain contact between the battery cells 12 and the thermal pad(s) 18.

Additionally, providing compression against the battery cell stack 10, at least to the broad side walls, may reduce battery cell swelling and prolong battery cell life. In some currently known battery cell housings 14, devices such as foam and/or springs (not shown) are used to keep the battery cells 12 in place. However, these devices lose their effectiveness over time and cannot provide uniform compression of the battery cell stack 10 and/or individual battery cells 12 due to gap variation. Other currently known battery cell housings 14 include devices such as smooth sided wedges (not shown) between the battery cell stack 10 and one or more interior walls of the battery cell housing 14.

However, these devices frequently slide out of place, thereby reducing the amount of compression against the battery cell stack 10 and/or ability to stabilize the battery cell stack 10 within the battery cell housing.

SUMMARY

[0006] Some embodiments advantageously provide a hold-down device or a hold-down assembly that secures and stabilizes one or more battery cells within a battery cell housing. In one embodiment, a hold-down device for use in a battery cell housing includes a wedge-shaped body including a first end and a second end opposite the first end, a planar surface between the first end and the second end, and a toothed surface between the first end and the second end and opposite the planar surface, the toothed surface having a plurality of teeth. [0007] In one aspect of the embodiment, the wedge-shaped body is tapered from the first end to the second end. In one aspect of the embodiment, the first end is oriented at a right angle to the planar surface.

[0008] In one aspect of the embodiment, the battery cell housing includes a toothed surface having a plurality of teeth, the plurality of teeth of the toothed surface of the wedge-shaped body being lockingly engageable with the plurality of teeth of the toothed surface of the battery cell housing to prevent movement of the hold-down device. In one aspect of the embodiment, the hold-down device is insertable into a gap between the battery cell housing and a battery cell stack within the battery cell housing.

[0009] In one embodiment, a battery module includes a battery cell housing including a plurality of interior surfaces that define an interior chamber, at least one of the interior surfaces being a toothed surface that includes a plurality of teeth, and a battery cell stack within the interior chamber. In this embodiment, the battery cell stack includes a plurality of battery cells and is located a distance from the toothed surface of the battery cell housing. In this embodiment, the battery module also includes a hold-down device located between the toothed surface of the battery cell housing and the battery cell stack, the hold-down device including a wedge-shaped body. In this embodiment, the wedge- shaped body has a first end and a second end opposite the first end, the wedge-shaped body being tapered from the first end to the second end, a planar surface between the first end and the second end, the planar surface being in contact with at least a portion of the battery cell stack, and a toothed surface between the first end and the second end and opposite the planar surface, the toothed surface being in contact with the toothed surface of the battery cell housing and having a plurality of teeth that are lockingly engageable with the plurality of teeth on the toothed surface of the battery cell housing.

[0010] In one aspect of the embodiment, the first end is oriented at a right angle to the planar surface and the toothed surface of the wedge-shaped body is oriented at an acute angle to the first end. In one aspect of the embodiment, the toothed surface of the battery cell housing is oriented at the same acute angle to the first end of the wedge-shaped body as the toothed surface of the wedge-shaped body.

[0011] In one embodiment, a hold-down assembly for use with a battery cell includes a stabilization plate including a planar central portion having a first edge and a second edge opposite the first edge, the planar central portion positionable across all of the plurality of battery cells, a first toothed element at the first edge, and a second toothed element at the second edge. [0012] In one aspect of the embodiment, the hold-down assembly further includes a first adjustable toothed element and a second adjustable toothed element. In one aspect of the embodiment, the first toothed element includes a first plurality of teeth, the second toothed element includes a second plurality of teeth, the first adjustable toothed element includes a third plurality of teeth, and the second adjustable toothed elements includes a fourth plurality of teeth, the first plurality of teeth being lockingly engageable with the third plurality of teeth and the second plurality of teeth being lockingly engageable with the fourth plurality of teeth. In one aspect of the embodiment, the planar central portion lies in a plane, at least a portion of each of the first and second toothed elements extending from the planar central portion in a direction that is orthogonal to the plane in which the planar central portion lies.

[0013] In one aspect of the embodiment, each of the first and second adjustable toothed elements is movingly couplable to the battery cell housing such that each of the first and second adjustable toothed elements is linearly movable in a direction that is orthogonal to the plane in which the planar central portion lies.

[0014] In one aspect of the embodiment, each of the first and second adjustable toothed elements is linearly movable in a direction that is parallel to the plane in which the planar central portion lies.

[0015] In one embodiment, a battery module includes a battery cell housing including a plurality of interior walls that define an interior chamber, the plurality of interior walls including a first interior wall and a second interior wall opposite the first interior wall and a battery cell stack within the interior chamber, the battery cell stack including a plurality of battery cells. In this embodiment, the battery module also includes: a hold-down assembly including a stabilization plate having a planar central portion, a first edge, and a second edge opposite the first edge, the planar central portion of the stabilization plate being positionable within the battery cell housing across each of the plurality of battery cells and lying in a plane; a first plurality of toothed elements, each of the first plurality of toothed elements being at the first edge of the stabilization plate and including a first plurality of teeth; a second plurality of toothed elements, each of the second plurality of toothed elements being at the second edge of the stabilization plate and including a second plurality of teeth; a first plurality of adjustable toothed elements, each of the first plurality of adjustable toothed elements being movable within the battery cell housing and including a third plurality of teeth, the third plurality of teeth being lockingly engageable with the first plurality of teeth; and a second plurality of adjustable toothed elements, each of the second plurality of adjustable toothed elements being movable within the battery cell housing and including a fourth plurality of teeth, the fourth plurality of teeth being lockingly engageable with the second plurality of teeth.

[0016] In one aspect of the embodiment, each of the first and second pluralities of adjustable toothed elements is movingly couplable to the battery cell housing.

[0017] In one aspect of the embodiment, the stabilization plate further has a first end and a second end opposite the first end, each of the first edge and the second edge being between the first end and the second end, each of the first end and the second end being couplable to the battery cell housing.

[0018] In one aspect of the embodiment, each of the first and second pluralities of adjustable toothed elements is linearly movable in a direction that is orthogonal to the plane in which a corresponding planar central portion lies.

[0019] In one aspect of the embodiment, each of the first and second pluralities of adjustable toothed elements is linearly movable in a direction that is parallel to the plane in which a corresponding planar central portion lies, each of the first and second pluralities of adjustable toothed elements being insertable between the stabilization plate and at least one of the plurality of battery cells.

[0020] In one aspect of the embodiment, each of the first and second pluralities of adjustable toothed elements includes a stop element that limits movement of each of the first and second pluralities of adjustable toothed elements toward a corresponding one of the plurality of battery cells.

[0021] These and other features and advantages of devices, systems, and methods according to this invention are described in, or are apparent from, the following detailed descriptions of various examples of embodiments.

BRIEF DESCRIPTION OF DRAWINGS

[0022] Various examples of embodiments of the systems, devices, and methods according to this invention will be described in detail, with reference to the following figures, wherein:

[0023] FIG. 1 shows a cross-sectional view of a currently known battery cell stack within a battery cell housing, with a gap between the battery cell stack and the battery cell housing;

[0024] FIG. 2 shows a cross-sectional view of a hold-down device positioned between a portion of a battery cell housing and a battery cell stack; [0025] FIG. 3 shows a perspective view of a hold-down device;

[0026] FIG. 4 shows a cross-sectional view of a battery cell stack within a battery cell housing and the hold-down device;

[0027] FIG. 5 shows a cross-sectional view of a battery cell stack within a battery cell housing and a plurality of hold-down devices;

[0028] FIG. 6 shows a schematic view of a plurality of hold down assemblies and a first embodiment of a stabilization plate within a battery cell housing and used with a plurality of battery cells;

[0029] FIG. 7 shows a top view of the plurality of hold down assemblies and a second embodiment of a stabilization plate within a battery cell housing and used with a plurality of battery cells;

[0030] FIG. 8 shows a cross-sectional view of a battery cell with a first embodiment of a hold-down assembly, the hold-down assembly being disengaged with a stabilization plate;

[0031] FIG. 9 shows a cross-sectional view of the battery cell with the first embodiment of a hold-down assembly of FIG. 8, the hold-down assembly being engaged with the stabilization plate;

[0032] FIG. 10 shows a cross-sectional view of a battery cell with a second embodiment of a hold-down assembly, the hold-down assembly being disengaged with a stabilization plate; and

[0033] FIG. 11 shows a cross-sectional view of the battery cell and the second embodiment of a hold-down assembly of FIG. 10, the hold-down assembly being engaged with the stabilization plate.

[0034] It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary to the understanding of the invention or render other details difficult to perceive may have been omitted. For ease of understanding and simplicity, common numbering of elements within the numerous illustrations is utilized when the element is the same in different Figures. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION

[0035] The system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0036] Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to lock-down assemblies to stabilize battery cells within a battery cell housing. Accordingly, the system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0037] As used herein, relational terms, such as“first” and“second,”“top” and“bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms“comprises,”“comprising,” “includes” and/or“including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0038] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0039] Referring now to the drawing figures in which like reference designations refer to like elements, a cross-sectional view of a hold-down device 20 positioned between a portion of a battery cell housing 22 and a battery cell stack 24 is shown in FIG. 2. The hold-down device 20 is configured for use in a battery cell housing 22 (only a portion of the housing 22 is shown in FIG. 2), such as to secure and stabilize a battery cell stack 24 (for example, a battery cell stack 24 as shown in FIGS. 4 and 5) within an interior chamber 25 of the battery cell housing 22 and to reduce or eliminate gap(s) 26 between the battery cell stack 24 and one or more interior walls of the battery cell housing 22. As used herein, the term“walls” includes side walls, the floor (or bottom wall), and the cover (or top wall opposite the bottom wall) of the battery cell housing 22. In one embodiment, the hold-down device 20 includes a wedge-shaped body 27, configured to be inserted into the battery cell housing 22 to a distance sufficient to secure and stabilize the battery cell stack 24, as discussed in greater detail below.

[0040] The wedge-shaped body 27 of the hold-down device 20 is shown in greater detail in FIG. 3. The wedge-shaped body 27 includes a first end 28 and a second end 30 opposite the first end, with the wedge-shaped body 27 tapering from the first end 28 to the second end 30. As shown in FIG. 2, the wedge-shaped body 27 includes a planar surface 32 extending between the first end 28 and the second end 30, the planar surface 32 being configured to be in contact with and parallel to, or at least substantially parallel to, a side surface 34 of an adjacent battery cell 36 of the battery cell stack 24 when the hold-down device 20 is inserted into the battery cell housing 22. In one embodiment, the first end 28 is oriented at a right angle, or approximately a right angle (90°) to the planar surface 32. The wedge-shaped body 27 further includes a toothed surface 38 having a plurality of teeth 40 that is located opposite the planar surface 32. In one embodiment, each of the plurality of teeth 40 is an elongate ridge that extends from one side of the wedge-shaped body 27 to the other (for example, as shown in FIG. 3). In one embodiment, the wedge-shaped body 27 is shaped like a right triangle, with the toothed surface 38 being the hypotenuse of the triangle and oriented at an acute angle to the first end 28. Further, the size and dimensions of the wedge-shaped body 27 are determined at least in part by the dimensions of the battery cell housing 22 and the battery cells 36 and/or battery cell stack 24. While specific examples are provided, one of skill in the art will appreciate that variations thereon may be acceptable for the purposes provided. For example, alternative geometric configurations accomplishing the same purposes are contemplated. In other examples, it is contemplated that surface roughness may be used in place of the toothed surface(s) described herein.

[0041] As shown in FIG. 2, the battery cell housing 22 includes a plurality of interior surfaces, at least one of which being a toothed surface 42 that includes a plurality of teeth 44. The size, tooth pitch, and configuration of teeth 44 on the toothed surface 42 of the battery cell housing 22 correspond to the size, tooth pitch, and configuration of teeth 40 on the toothed surface 38 of the wedge-shaped body 27. Further, the toothed surface 42 within the battery cell housing 22 is slanted relative to the side surface 34 of the battery cell stack 24 at the same, or approximately the same, angle that the toothed surface 38 is slanted relative to the planar surface 32 of the wedge-shaped body 27 is. Put another way, the toothed surface 42 of the battery cell housing 22 is oriented at the same, or approximately the same, acute angle relative to the first end 28 of the wedge-shaped body 27 as the toothed surface 38 of the wedge-shaped body 27. Thus, the teeth 40, 44 of the toothed surfaces 38, 42 are configured to be lockingly engaged with each other when the hold-down device 20 is inserted between the battery cell stack 24 and the toothed surface 42 of the battery cell housing 22. Although not shown, the hold-down device 20 may further include one or more handles or projections coupled to the wedge-shaped body 27 for removing and/or repositioning the hold-down device 20.

[0042] During assembly, the battery cells 36 are placed within the battery cell housing 22 to form the battery cell stack 24, such that the gap 26 is located between the battery cell stack 24 and the toothed surface 42. The hold-down device 20 is then inserted into the gap 26, toward the floor 46 of the inside of the battery cell housing 22. The distance the hold-down device 20 is inserted into the battery cell housing 22 depends at least in part on the size of the gap 26 between battery cell stack 24 and the toothed surface 42 of the battery cell housing 22. In one embodiment, the hold-down device 20 includes a wedge- shaped body 27, and the hold-down device 20 is inserted into the battery cell housing 22 with the second end 30 of the wedge-shaped body 27 leading. Due to the shape of the wedge-shaped body 27, the hold-down device 20 may be used to eliminate or reduce a gap 26 of any size. For example, the larger the gap 26, the longer the distance by which the hold-down device 20 is inserted into the battery cell housing 22. The size, number, and configuration of the teeth 40, 44 on the toothed surfaces 38, 42 may be chosen such that the hold-down device 20 will remain in place, even in the occurrence of a higher load due to cell expansion forces within the battery cell 36 (and battery cell swelling, as a result), inertia acting upon the battery cell stack 24 during shock or vibration, and/or other factors. Use of the hold-down device 20 may also allow for the use of thinner thermal pads between the battery cell stack 24 and/or battery cells 36 and the battery cell housing 22, which reduces cost and increases thermal conductivity of the thermal pads.

Moreover, the use of the hold-down device 20 herein may also allow for manufacturing variation and tolerances in the construction of the battery cell and/or hold-down device.

[0043] Depending on the size and/or amount of gaps 26 between the battery cell stack 24 and the battery cell housing 22, one or more hold-down devices 20 may be used. The battery cell stack 24, battery cell housing, and hold-down device(s) 20 are collectively referred to as a battery module 48. In one embodiment, the battery cell housing 22 includes one toothed surface 42 and one hold-down device 20 is used (for example, as shown in FIG. 4). In another embodiment, the battery cell housing 22 includes two toothed surfaces 42, such as at opposite ends of the battery cell housing 22, and two hold down devices 20 are used (for example, as shown in FIG. 5). However, it will be understood that the battery cell housing 22 may include any number of toothed surfaces 42, and more than one hold-down device 20 may be used to engage with each toothed surface 42. It will further be understood that fewer hold-down devices 20 than toothed surfaces 42 may be used. Additionally, because the hold-down device 20 is configured to reduce or eliminate gap(s) 26 between the battery cell stack 24 and one or more interior walls (including, for example, the floor 46 and/or the cover) of the battery cell housing 22, it will be understood that one or more hold-down devices 20 may be inserted into the battery cell housing 22 at locations other than those shown. For example, one or more hold-down devices 20 may be inserted between the battery cell stack 24 and the cover and/or the floor 46 of the battery cell housing 22. Likewise, in one or more examples of embodiments, one or more gaps may be desirable for, among other things, permitting air circulation and cooling of the battery cell stack. For instance, the hold-down device may have one or more channels or a pattern of channels for air flow. Alternatively, a heat sink may be wedged within the gap along with the hold-down device(s) or in some examples the hold-down device may be formed of a material having heat-sink qualities, such as aluminum.

[0044] Referring now to FIGS. 6 and 7, schematic views of a hold-down assembly 50 used within a battery cell housing 52 are shown. The hold-down assembly 50 is configured for use in a battery cell housing 52, such as to secure and stabilize a battery cell 54 therein and to reduce or eliminate gap(s) (not shown in FIG. 6) between the battery cell 54 and one or more interior walls of the battery cell housing 52. In one embodiment, a battery module 56 includes a hold-down assembly 50 having a stabilization plate 60 and a plurality of hold-down units 61 for each battery cell 54 in a battery cell stack 58. A first embodiment of a stabilization plate 60 is shown in FIG. 6 and a second embodiment of a stabilization plate is shown in FIG. 7.

[0045] Each hold-down unit 61 is configured to lockingly engage with the stabilization plate 60. The stabilization plate 60 is coupled to at least one inner wall of the battery cell housing 52 and, in one embodiment, is movingly coupled to the battery cell housing 52 such that the stabilization plate is vertically movable relative to the battery cell stack 58 over a limited, pre-determined distance. In another embodiment, the stabilization plate 60 is unattached from the battery cell housing 52, and instead is positioned on top of the battery cell stack 58. In the first embodiment shown in FIG. 6, the stabilization plate 60 includes a planar central portion 66 that extends over each of the battery cells 54 in the battery cell stack 58, between the terminals 64 of each battery cell 54. In the second embodiment shown in FIG. 7, the stabilization plate 60 also includes a plurality of lateral planar portions 67 that each extend perpendicularly from the planar central portion 66. In either embodiment, the stabilization plate 60 further includes a first toothed element 68A at a first edge of the planar central portion 66, and a second toothed element 68B at a second edge of the planar central portion 66 opposite the first toothed element 68A.

[0046] Each hold-down unit 61 includes a first adjustable toothed element 70 A and a second adjustable toothed element 70B. In one embodiment, each adjustable toothed element 70A, 70B is movably coupled to an inner surface of the battery cell housing 52. For example, in one embodiment, the battery cell housing 14 includes a plurality of interior walls, including a floor, a cover, and at least four interior walls 72 defining an interior chamber 74 of the battery cell housing 52, the interior walls including a first interior wall 72A and a second interior wall 72B opposite the first interior wall 72A, with the first adjustable toothed element 70 A being movably coupled to the first interior wall 72A and extending into the interior chamber 74 and the second adjustable toothed element 70B being movably coupled to the second interior wall 72B and extending into the interior chamber 74. In one embodiment, each adjustable toothed element 70A, 70B is spring-mounted to the battery cell housing 52, such that the adjustable toothed element 70A, 70B may be moved linearly with respect to the battery cell 54. In the first embodiment shown in FIGS. 8 and 9, the adjustable toothed elements 70 A, 70B are linearly movable in a vertical direction along a distance that is orthogonal to, or at least substantially orthogonal to, the plane in which the planar central portion 66 of the stabilization plate 60 lies. Further, the toothed elements 68A, 68B and the adjustable toothed elements 70 A, 70B include a complementary number, size, and configuration of teeth 76A, 76B, 78A, 78B, respectively, such that the teeth 78A of the first adjustable toothed element 70A are configured to be lockingly engaged with the teeth 76 A of the first toothed element 68A of the stabilization plate 60 and the teeth 78B of the second adjustable toothed element 70B are configured to be lockingly engaged with the teeth 76B of the second toothed element 68B of the stabilization plate 60. [0047] The toothed elements 68 A, 68B of the stabilization plate 60 and the adjustable toothed elements 70 A, 70B may have any suitable size, shape, or configuration, as long as they are configured to be lockingly engaged with each other. Further, each adjustable toothed element 70A, 70B includes an arm 80 that extends from the inner surface of the battery cell housing 52 toward the corresponding toothed element 68A, 68B of the stabilization plate 60, thereby positioning the teeth 76 of the toothed elements 68 A, 68B and the teeth 78 of the adjustable toothed elements 70 A, 70B such that they may be engaged with each other. In the first embodiment shown in FIGS. 8 and 9, the toothed elements 68A, 68B extend from the planar central portion 66 in a direction that is orthogonal to, or at least substantially orthogonal to, the plane in which the planar central portion 66 lies. Further, the teeth 76 are located on the outer surfaces of the toothed elements 68A, 68B (that is, the surfaces facing in opposite directions from each other). Likewise, in the first embodiment, the adjustable toothed elements 70A, 70B include an inner surface on which the teeth 78 are located, which inner surface extends in a direction that is orthogonal to, or at least substantially orthogonal to, the plane in which the planar central portion 66 lies, such that the teeth 76, 78 may be engaged with each other. When the teeth 76, 78 are properly lockingly engaged, the pressure of the stabilization plate 60 on each battery cell 54 stabilizes and provides a pre-loading compression force on the battery cell stack 58, which in some examples may provide for approximately uniform compression. Additionally, the stabilization plate 60 helps transfer the hold down force to the battery cell housing 52.

[0048] In the second embodiment shown in FIGS. 10 and 11, the stabilization plate 60 is coupled to at least one interior wall 72 of the battery cell housing 52 and the adjustable toothed elements 70 A, 70B are unattached from, or not coupled to, the battery cell housing 52 and are linearly movable in a horizontal direction along a distance that is parallel to, or at least substantially parallel to, the plane in which the planar central portion 66 of the stabilization plate 60 lies. The adjustable toothed elements 70A, 70B are inserted between the stabilization plate 60 and the battery cell stack 58 (for example, between the stabilization plate 60 and each of the battery cells 54) to reduce or eliminate gap(s) between the battery cell stack 58 and the stabilization plate 60 and/or the interior walls 72 of the battery cell housing 52.

[0049] As in the first embodiment shown in FIGS. 8 and 9, the stabilization plate 60 of the second embodiment shown in FIGS. 10 and 11 includes a plurality of toothed elements 68. Toothed elements being on opposite edges of the stabilization plate from each other are referred to in the figures as toothed element 68A and 68B. Each toothed element 68A, 68B includes a first portion 82 that extends in a direction that is orthogonal to, or at least substantially orthogonal to, the plane in which the planar central portion 66 lies, and a second portion 84 that extends from the first portion 82 in a direction that is parallel to, or at least substantially parallel to, the plane in which the planar central portion 66 lies. The second portion includes a slanted lower surface (that is, the surface that is closer to the battery cell 54) on which the teeth 76 are located. Likewise, in the second embodiment, each adjustable toothed element 70A, 70B includes a slanted upper surface (that is, the surface that is farther from the battery cell 54) on which the teeth 78 are located. The slanted surfaces of the toothed elements 60 A, 60B and the slanted surfaces of the adjustable toothed elements 70A, 70B are configured such that the teeth 76, 78 are in positioned to engage each other when the battery cell stack 58 is secured and stabilized within the battery cell housing 52. The adjustable toothed elements 70A, 70B will move linearly (horizontally) along the directions shown in FIG. 10 and 11 to secure and stabilize the battery cell 54. Thus, the adjustable toothed elements 70A, 70B shown in FIGS. 10 and 11 function similar to the wedge-shaped body 27 shown and described in FIGS. 1-5 to reduce or eliminate gap(s) between the battery cell stack 58 and the stabilization plate 60 and/or the battery cell housing 52. When the adjustable toothed elements 70 A, 70B are lockingly engaged with the toothed elements 60A, 60B of the stabilization plate 60, the insertion of the adjustable toothed elements 70A, 70B between the battery cell stack 58 and the stabilization plate 60 provides a pre-loading compression force on the battery cell stack 58. Additionally, the stabilization plate 60 helps transfer the hold down force to the battery cell housing 52.

[0050] While specific examples are provided, one of skill in the art will appreciate that variations thereon may be acceptable for the purposes provided.

[0051] In one embodiment, during assembly of the battery module 56, the battery cells 54 are assembled into a battery cell stack 58 and secured and stabilized within the battery cell housing 52 using a hold-down unit 61 for each battery cell 54. Once the battery cell stack 58 is within the battery cell housing 52 with a stabilization plate 60 coupled to at least one interior wall 72 of the battery cell housing 52 and/or positioned on top of the battery cell stack 58. The adjustable toothed elements 70A, 70B may be coupled to the battery cell housing 52 (as shown in FIGS. 8 and 9) or not coupled to the battery cell housing 52 (as shown in FIGS. 10 and 11). Once the battery cell stack 58 and stabilization plate 60 are in place, the adjustable toothed elements 70 A, 70B are moved from an assembly position to an engagement position (in which the teeth 78A, 78B are engageable with the teeth 76A, 76B of the stabilization plate 60). In one non-limiting example, the adjustable toothed elements 70A, 70B may be located between the terminals 64 of adjacent battery cells 54 so that engagement between the adjustable toothed elements 70A, 70B and the toothed elements 68A, 68B of the stabilization plate 60 does not interfere with, or is not blocked by, the terminals 64. In one embodiment, each adjustable toothed element 70A, 70B includes a stop element 86 that limits linear movement of the adjustable toothed element 70A, 70B toward the battery cell 54. Each adjustable toothed element 70A, 70B is linearly moved toward a corresponding battery cell 54 (either horizontally or vertically), such that the teeth 76, 78 engage with each other, until the stop element 86 of each adjustable toothed element 70 A, 70B comes into contact with the corresponding battery cell 54 and prevents further movement of the adjustable toothed element 70A, 70B. When the stop element 86 is in contact with the corresponding battery cell 54, the length of the stop element 86 causes a gap to be maintained between the stabilization plate 60 (for example, the central portion 66 of the stabilization plate 60) and the upper surface of the battery cell stack 58, as shown in FIGS. 9 and 11. The configuration of the teeth 76 of the toothed elements 68 A, 68B and the teeth 78 of the adjustable toothed elements 70 A, 70B prevents linear movement of the adjustable toothed elements 70A, 70B away from the battery cell 54 once the stop element 86 comes into contact with the corresponding battery cell 54. Thus, the hold down assembly 50 allows each battery cell 54 to be individually secured and stabilized within the battery cell housing 52, even if all of the battery cells 54 within the battery cell stack 58 are not aligned with each other.

[0052] As each adjustable toothed element 70A, 70B is independently movable, each battery cell 54 may be secured and stabilized, even if the battery cells 54 are positioned unevenly within the battery cell stack 58. Thus, each battery cell 54, and the battery cell stack 58 as a whole, is secured and stabilized within the battery cell housing 52, even in the occurrence of a higher load due to cell expansion forces within the battery cell 54, inertia acting upon the battery cell stack 58 during shock or vibration, and/or other factors. Use of the hold-down assembly 50 also allows for the use of thinner thermal pads between the battery cell stack 58 and/or battery cells 54 and the battery cell housing 52, which reduces cost and increases thermal conductivity of the thermal pads.

[0053] Of note, in some embodiments, the teeth on the adjustable toothed elements 70 and the toothed elements 68, and those on the hold down device 20 and the battery housing 22, are arranged to allow sliding engagement in one direction, e.g., the direction of insertion, but not to allow release. The operation is similar to the operation of a plastic cable tie.

[0054] In one embodiment, a hold-down device 20 for use in a battery cell housing 22 includes a wedge-shaped body 27 including a first end 28 and a second end 30 opposite the first end 28, a planar surface 32 between the first end 28 and the second end 30, and a toothed surface 38 between the first end 28 and the second end 30 and opposite the planar surface 32, the toothed surface 38 having a plurality of teeth 40.

[0055] In one aspect of the embodiment, the wedge-shaped body 27 is tapered from the first end 28 to the second end 30. In one aspect of the embodiment, the first end 28 is oriented at a right angle to the planar surface 32.

[0056] In one aspect of the embodiment, the battery cell housing 22 includes a toothed surface 42 having a plurality of teeth 44, the plurality of teeth 40 of the toothed surface 38 of the wedge-shaped body 27 being lockingly engageable with the plurality of teeth 44 of the toothed surface 42 of the battery cell housing 22 to prevent movement of the hold down device 20. In one aspect of the embodiment, the hold-down device 20 is sized and insertable into a gap 26 between the battery cell housing 22 and a battery cell stack 24 within the battery cell housing 22.

[0057] In one embodiment, a battery module 48 includes a battery cell housing 22 including a plurality of interior surfaces that define an interior chamber 25, at least one of the interior surfaces being a toothed surface 42 that includes a plurality of teeth 44, and a battery cell stack 24 within the interior chamber 25. In this embodiment, the battery cell stack 24 includes a plurality of battery cells 36 and is located a distance from the toothed surface 42 of the battery cell housing 22. In this embodiment, the battery module 48 also includes a hold-down device 20 located between the toothed surface 42 of the battery cell housing 22 and the battery cell stack 24, the hold-down device 20 including a wedge- shaped body 27. In this embodiment, the wedge-shaped body 27 has a first end 28 and a second end 30 opposite the first end 28, the wedge-shaped body 27 being tapered from the first end 28 to the second end 30, a planar surface 32 between the first end 28 and the second end 30, the planar surface 32 being in contact with at least a portion of the battery cell stack 24, and a toothed surface 38 between the first end 28 and the second end 30 and opposite the planar surface 32, the toothed surface 38 being in contact with the toothed surface 42 of the battery cell housing 22 and having a plurality of teeth 40 that are lockingly engageable with the plurality of teeth 44 on the toothed surface 42 of the battery cell housing 22.

[0058] In one aspect of the embodiment, the first end 28 is oriented at a right angle to the planar surface 32 and the toothed surface 38 of the wedge-shaped body 27 is oriented at an acute angle to the first end 28. In one aspect of the embodiment, the toothed surface 42 of the battery cell housing 22 is oriented at the same acute angle to the first end 28 of the wedge-shaped body 27 as the toothed surface 38 of the wedge-shaped body 27.

[0059] In one embodiment, a hold-down assembly 50 for use with a battery cell 54 includes a stabilization plate 60 including a planar central portion 66 having a first edge and a second edge opposite the first edge, the planar central portion positionable across all of the plurality of battery cells, a first toothed element 68 A at the first edge, and a second toothed element 68B at the second edge.

[0060] In one aspect of the embodiment, the hold-down assembly 50 further includes a first adjustable toothed element 70A and a second adjustable toothed element 70B. In one aspect of the embodiment, the first 68A toothed element has includes a first plurality of teeth 76A, the second 68B toothed element includes a second plurality of teeth 76B, the first adjustable toothed element 70A includes a third plurality of teeth 78 A, and the second 70B adjustable toothed element includes a fourth plurality of teeth 78B, the first plurality of teeth 76A being lockingly engageable with the third plurality of teeth 78 A, and the second plurality of teeth 76B being lockingly engageable with the fourth plurality of teeth 78B. In one aspect of the embodiment, the planar central portion 66 lies in a plane, at least a portion of each of the first 68A and second 68B toothed elements extending from the planar central portion 66 in a direction that is orthogonal to the plane in which the planar central portion 66 lies.

[0061] In one aspect of the embodiment, each of the first 70A and second 70B adjustable toothed elements is movingly couplable to the battery cell housing 52 such that each of the first 70A and second 70B adjustable toothed elements is linearly movable in a direction that is orthogonal to the plane in which the planar central portion 66 lies.

[0062] In one aspect of the embodiment, each of the first 70 A and second 70B adjustable toothed elements is linearly movable in a direction that is parallel to the plane in which the planar central portion 66 lies.

[0063] In one embodiment, a battery module 56 includes a battery cell housing 52 including a plurality of interior walls 72 that define an interior chamber 74, the plurality of interior walls 72 including a first interior wall 72A and a second interior wall 72B opposite the first interior wall 72A and a battery cell stack 58 within the interior chamber 74, the battery cell stack 58 including a plurality of battery cells 54. In this embodiment, the battery module 56 also includes: a hold-down assembly 50 including a stabilization plate 60 having a planar central portion 66, a first edge, and a second edge opposite the first edge, the planar central portion 66 of the stabilization plate being positionable within the battery cell housing 52 across each of the plurality of battery cells 54 and lying in a plane; a first plurality of toothed elements 68A, each of the first plurality of toothed elements 68A being at the first edge of the stabilization plate 60 and including a first plurality of teeth 76A; a second plurality of toothed elements 68B, each of the second plurality of toothed elements 68B being at the second edge of the stabilization plate 60 and including a second plurality of teeth 76B; a first plurality of adjustable toothed elements 70A, each of the first plurality of adjustable toothed elements 70A being movable within the battery cell housing 52 and including a third plurality of teeth 78A, the third plurality of teeth 78A being lockingly engageable with the first plurality of teeth 76A; and a second plurality of adjustable toothed elements 70B, each of the second plurality of adjustable toothed elements 70B being movable within the battery cell housing 52 and including a fourth plurality of teeth 78B, the fourth plurality of teeth 78B being locking engageable with the second plurality of teeth 76B.

[0064] In one aspect of the embodiment, each of the first 70A and second 70B pluralities of adjustable toothed elements is movingly couplable to the battery cell housing 52.

[0065] In one aspect of the embodiment, the stabilization plate 60 further has a first end and a second end opposite the first end, each of the first edge and the second edge being between the first end and the second end, each of the first end and the second end being couplable to the battery cell housing 52.

[0066] In one aspect of the embodiment, each of the first 70A and second 70B pluralities of adjustable toothed elements is linearly movable in a directly that is orthogonal to the plane in which a corresponding planar central portion 66 lies.

[0067] In one aspect of the embodiment, each of the first 70A and second 70B pluralities of adjustable toothed elements is linearly movable in a directly that is parallel to the plane in which a corresponding planar central portion 66 lies, each of the first 70A and second 70B pluralities of adjustable toothed elements being insertable between the stabilization plate 60 and at least one of the plurality of battery cells 54.

[0068] In one aspect of the embodiment, each of the first 70 A and second 70B pluralities of adjustable toothed elements includes a stop element 86 that limits movement of each of the first 70 A and second 70B pluralities of adjustable toothed elements toward a corresponding one of the plurality of battery cells 54.

[0069] It will be appreciated by persons skilled in the art that the present embodiments are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.

[0070] The technical effects and technical problems in the specification are exemplary and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.