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Title:
PARALLEL BATTERY STRINGS FOR ELECTRIC VEHICLES
Document Type and Number:
WIPO Patent Application WO/2006/079202
Kind Code:
A1
Abstract:
An electric vehicle power supply having first and second battery cell groups (24, 26) electrically connected in parallel with one another. Each battery cell group contains a plurality of electrically series-connected battery cell sub-groups (24: 30, 32, 34, 36; 26: 40, 42, 44, 46). Each battery cell sub-group contains a plurality of electrically parallel- connected battery cells (30: 30A, 30B; 32: 32A, 32B; 34: 34A, 34B; 36: 36A, 36B; 40: 40A, 40B; 42: 42A, 42B; 44: 44A, 44B; 46: 46A, 46B). Each battery cell group operates independently of the others, facilitating continued vehicle operation notwithstanding a failure of one or more of the other battery cell groups.

Inventors:
SIMMONDS STEWART NEIL (CA)
Application Number:
PCT/CA2006/000094
Publication Date:
August 03, 2006
Filing Date:
January 25, 2006
Export Citation:
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Assignee:
MOUNTAIN POWER INC (CA)
SIMMONDS STEWART NEIL (CA)
International Classes:
H02J7/00; H01M2/10
Foreign References:
US6121752A2000-09-19
US5675234A1997-10-07
US6828757B22004-12-07
Attorney, Agent or Firm:
Wiggs, Blake R. (Suite 480 - The Station 601 West Cordova Stree, Vancouver British Columbia V6B 1G1, CA)
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Claims:
WHAT IS CLAIMED IS:
1. A power supply characterized by at least a first battery cell group (24) and a second battery cell group (26), the first battery cell group (24) electrically connected in parallel with the second battery cell group (26), each battery cell group (24, 26) having a plurality of electrically seriesconnected battery cell subgroups (24: 30, 32, 34, 36; 26: 40, 42, 44, 46), each battery cell subgroup having a plurality of electrically parallelconnected battery cells (30: 3OA, 3OB; 32: 32A, 32B; 34: 34A, 34B; 36: 36A, 36B; 40: 4OA, 4OB; 42: 42A, 42B; 44: 44A, 44B; 46: 46A, 46B).
2. A power supply having a plurality of electrically parallelconnected battery cell groups (24, 26), characterized by each battery cell group (24, 26) having a plurality of electrically seriesconnected battery cell subgroups (24: 30, 32, 34, 36; 26: 40, 42, 44, 46), each battery cell subgroup having a plurality of electrically parallelconnected battery cells (30: 30A, 3OB; 32: 32A, 32B; 34: 34A, 34B; 36: 36A, 36B; 40: 4OA, 4OB; 42: 42A, 42B; 44: 44A, 44B; 46: 46A, 46B).
3. A power supply as defined in claim 2, further characterized by a detector (92, 94, 94, 98, 100, 102, 104, 106) corresponding to each one of the battery cell subgroups (30, 32, 34, 36, 40, 42, 44, 46), each detector electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the voltage output by each battery cell within the battery cell subgroup corresponding to the detector.
4. A power supply as defined in claim 2, further characterized by a detector (92, 94, 94, 98, 100, 102, 104, 106) corresponding to each one of the battery cell subgroups (30, 32, 34, 36, 40, 42, 44, 46), each detector electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the current output by each battery cell within the battery cell subgroup corresponding to the detector.
5. A power supply as defined in claim 2, further characterized by a detector (92, 94, 94, 98, 100, 102, 104, 106) corresponding to each one of the battery cell subgroups (30, 32, 34, 36, 40, 42, 44, 46), each detector connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the temperature of each battery cell within the battery cell subgroup corresponding to the detector.
6. A power supply as defined in claim 2, further characterized by a detector (92, 94, 94, 98, 100, 102, 104, 106) corresponding to each one of the battery cell subgroups (30, 32, 34, 36, 40, 42, 44, 46), each detector electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the capacity of each battery cell within the battery cell subgroup corresponding to the detector.
7. A power supply as defined in claim 3, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the current output by each battery cell within the battery cell subgroup corresponding to the detector.
8. A power supply as defined in claim 7, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the temperature of each battery cell within the battery cell subgroup corresponding to the detector.
9. A power supply as defined in claim 8, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the capacity of each battery cell within the battery cell subgroup corresponding to the detector.
10. A power supply as defined in claim 4, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further connected to the bat tery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the temperature of each battery cell within the battery cell subgroup corresponding to the detector.
11. A power supply as defined in claim 10, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the capacity of each battery cell within the battery cell sub group corresponding to the detector.
12. A power supply as defined in claim 5, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the voltage of each battery cell within the battery cell subgroup corresponding to the detector.
13. A power supply as defined in claim 12, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically con nected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the capacity of each battery cell within the battery cell subgroup corresponding to the detector.
14. A power supply as defined in claim 6, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the voltage of each battery cell within the battery cell subgroup corresponding to the detector.
15. A power supply as defined in claim 14, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corre sponding to the detector to produce output signals representative of the current output by each battery cell within the battery cell subgroup corresponding to the detector.
16. A power supply as defined in claim 4, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup correspond ing to the detector to produce output signals representative of the capacity of each battery cell within the battery cell subgroup corresponding to the detector.
17. A power supply as defined in claim 5, wherein each detector (92, 94, 94, 98, 100, 102, 104, 106) is further electrically connected to the battery cells within the battery cell subgroup corresponding to the detector to produce output signals representative of the capacity of each battery cell within the battery cell subgroup corresponding to the detector.
18. A power supply method characterized by: (a) dividing a plurality of battery cells (3OA, 3OB; 32A, 32B; 34A, 34B; 36A, 36B; 4OA, 4OB; 42A, 42B; 44A, 44B; 46A, 46B) into subgroups (30, 32, 34, 36, 40, 42, 44, 46); (b) dividing the subgroups into a plurality of groups (24, 26); (c) electrically connecting the battery cells within each subgroup in parallel; and (d) electrically connecting the subgroups within each group in series.
19. A power supply method as defined in claim 18, further characterized by: (a) monitoring each one of the subgroups to detect a predefined characteristic of each one of the subgroups; (b) comparing the detected characteristic of each one of the subgroups with a predefined threshold value; and (c) if the detected characteristic of any one of the subgroups does not exceed the predefined threshold value, electrically isolating the group containing that one of the subgroups.
20. A power supply method as defined in claim 18, further characterized by: (a) monitoring each one of the battery cells to detect a predefined characteristic of each one of the battery cells; (b) comparing the detected characteristic of each one of the battery cells with a predefined threshold value; and (c) if the detected characteristic of any one of the battery cells does not exceed the predefined threshold value, electrically isolating the group containing that one of the battery cells.
21. A power supply method as defined in claim 19, wherein the characteristic is the voltage output by the subgroup.
22. A power supply method as defined in claim 20, wherein the characteristic is the voltage output by the battery cell.
23. A power supply method as defined in claim 19, wherein, the characteristic is the current output by the subgroup.
24. A power supply method as defined in claim 20, wherein the characteristic is the current output by the battery cell.
25. A power supply method as defined in claim 19, wherein the characteristic is the temperature of the subgroup.
26. A power supply method as defined in claim 20, wherein the characteristic is the temperature of the battery cell.
27. A power supply method as defined in claim 19, wherein the characteristic is the capacity of the subgroup.
28. A power supply method as defined in claim 20, wherein the characteristic is the capacity of the battery cell.
Description:
PARALLEL BATTERY STRINGS FOR ELECTRIC VEHICLES

Reference to Related Application

[0001] This application claims the benefit of United States provi- sional patent application serial no. 60/647,422 filed 28 January 2005.

Technical Field

[0002] An electric vehicle power supply containing at least two battery cell groups electrically connected in parallel with one another. Each group contains a plurality of battery cell sub-groups electrically connected in series with one another. Each sub-group contains a plurality of battery cells electrically connected in parallel with one another. Each battery cell group operates independently of the others, facilitating continued vehicle operation notwithstanding a failure of one or more of the other battery cell groups.

Background

[0003] Electric vehicles (i.e. electric cars, hybrid electric cars, underwater vehicles, electric aircraft, etc.) have battery type power supplies. Since the output voltage and power capacity capabilities of a single battery cell are inadequate to satisfy the output voltage and power capacity requirements of a typical electric vehicle, a plurality of cells are normally provided in an electric vehicle power supply. The cells are electrically connected to one another in series or in parallel in order to satisfy the output voltage and power capacity requirements of a particular electric vehicle.

[0004] For example, Figure 1 schematically depicts four groups 10, 12, 14, 16 of battery cells which have been predetermined to be capable of being configured to meet the output voltage and power capacity requirements of a particular electric vehicle. Group 10 consists of a first group of four cells 1OA, 1OB, 1OC, 1OD which are electrically connected in parallel with one another. Group 12 consists of a second group of four cells 12A, 12B, 12C, 12D which are electrically con-

nected in parallel with one another. Group 14 consists of a third group of four cells 14A, 14B, 14C, 14D which are electrically connected in parallel with one another. Group 16 consists of a fourth group of four cells 16A, 16B, 16C, 16D which are electrically connected in parallel with one another. The four groups 10, 12, 14, 16 are configured to form a power supply by electrically connecting them in series with one another as shown in Figure 2. More particularly, connector 18 electrically connects first and second groups 10, 12 in series with one another; connector 20 electrically connects second and third groups 12, 14 in series with one another; and connector 22 electrically connects third and fourth groups 14, 16 in series with one another. [0005] A disadvantage of the Figure 2 configuration is that if an electrical fault causes an open circuit condition in any one of groups 10, 12, 14 or 16 (as is schematically illustrated in Figure 3 by severing group 12's series connection to groups 10, 14) then the entire power supply consisting of groups 10, 12, 14 and 16 is rendered inoperative by the lack of electrical continuity through groups 10, 12, 14 and 16.

Brief Description of Drawings [0006] Figure 1 schematically depicts four groups of prior art battery cells, with the cells in each group being electrically connected in parallel with one another.

[0007] Figure 2 shows the Figure 1 groups electrically connected in series with one another to form a prior art power supply. [0008] Figure 3 schematically depicts an open circuit fault in the

Figure 2 prior art power supply.

[0009] Figure 4 schematically depicts two battery cell groups electrically connected in parallel with one another to form a power supply. Each group has four battery cell sub-groups electrically con- nected in series with one another. Each sub-group has two battery cells electrically connected in parallel with one another.

[0010] Figure 5 schematically depicts an open circuit fault in the Figure 4 power supply.

Description [0011] Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense. [0012] Figure 4 schematically depicts two groups 24, 26 of battery cells which have been predetermined to be capable of being configured to meet the output voltage and power capacity requirements of a partic- ular electric vehicle. Groups 24, 26 are electrically connected in parallel with one another by connectors 28, 29. Group 24 consists of four battery cell sub-groups 30, 32, 34, 36 which are electrically connected in series with one another. More particularly, connector 48 electrically connects sub-groups 30, 32 in series with one another; connector 50 electrically connects sub-groups 32, 34 in series with one another; and connector 52 electrically connects sub-groups 34, 36 in series with one another. Group 26 consists of another four battery cell sub-groups 40, 42, 44, 46 which are electrically connected in series with one another. More particularly, connector 54 electrically connects sub-groups 40, 42 in series with one another; connector 56 electrically connects sub-groups 42, 44 in series with one another; and connector 58 electrically connects sub-groups 44, 46 in series with one another. [0013] Sub-group 30 consists of two cells 3OA, 30B which are electrically connected in parallel with one another by connectors 60, 62. Sub-group 32 consists of two cells 32 A, 32B which are electrically connected in parallel with one another by connectors 64, 66. Sub-group

- A -

34 consists of two cells 34 A, 34B which are electrically connected in parallel with one another by connectors 68, 70. Sub-group 36 consists of two cells 36A, 36B which are electrically connected in parallel with one another by connectors 72, 74. [0014] Sub-group 40 consists of two cells 4OA, 4OB which are electrically connected in parallel with one another by connectors 76, 78. Sub-group 42 consists of two cells 42 A, 42B which are electrically connected in parallel with one another by connectors 80, 82. Sub-group 44 consists of two cells 44A, 44B which are electrically connected in parallel with one another by connectors 84, 86. Sub-group 46 consists of two cells 46A, 46B which are electrically connected in parallel with one another by connectors 88, 90.

[0015] If an electrical fault causes an open circuit condition in any one of sub-groups 30, 32, 34, 36, 40, 42, 44 or 46 (as is schematically illustrated in Figure 5 by severing group 32 's series connection to groups 30, 34) then the group containing the faulty sub-group (i.e. group 24 in the Figure 5 example) is rendered inoperative by the lack of electrical continuity through that group. However, the other group(s) (i.e. group 26 in the Figure 5 example) remain operative as long as electrical continuity is maintained through each of the other group(s). Consequently, the power supply as a whole is not rendered inoperative. Only the battery cell group containing the faulty cell(s) is rendered inoperative; battery cell groups containing no faulty cell(s) remain operative. [0016] Each battery cell sub-group can be monitored by connecting a suitable detector thereto. For example, Figure 4 shows detectors 92, 94, 96, 98, 100, 102, 104, 106 connected to battery cell sub-groups 30, 32, 34, 36, 40, 42, 44, 46 respectively. Each detector produces an output signal representative of a selected operating parameter. For example, some or all of the detectors may be voltage detectors, each of which produces an output signal representative of the voltage output by

each battery cell within the battery cell sub-group to which the voltage detector is connected.

[0017] Alternatively, some or all of the detectors may be current detectors. Each such detector may be electrically connected to the battery cells within a particular battery cell sub-group to produce an output signal representative of the current output by each battery cell within the battery cell sub-group to which the current detector is connected. [0018] As yet another alternative, some or all of the detectors may be temperature detectors. Each such detector may be connected to the battery cells within a particular battery cell sub-group to produce an output signal representative of the temperature of each battery cell within the battery cell sub-group to which the temperature detector is connected. [0019] As a still further alternative, some or all of the detectors may be power capacity detectors. Each such detector may be electrically connected to the battery cells within a particular battery cell subgroup to produce an output signal representative of the power capacity of each battery cell within the battery cell sub-group to which the power capacity detector is connected.

[0020] The output signals produced by the respective detectors can be transmitted to a suitable controller (not shown) which monitors the signals and compares them with predefined threshold signals. If a fault condition (e.g. an open circuit condition, an excess temperature condi- tion, or a cumulative power capacity value which does not exceed a predefined minimum power capacity threshold) is detected within either one of groups 24, 26 then that group can be electrically isolated from the other group— which remains operative to provide power to the vehicle. [0021] As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possi-

ble in the practice of this invention without departing from the scope thereof. For example, Figure 4 shows two battery cell groups 24, 26 but the power supply may contain more than two battery cell groups electrically connected in parallel with one another. As another exam- pie, Figure 4 shows four series-connected battery cell sub-groups 30, 32, 34, 36 and 40, 42, 44, 46 in each of battery cell groups 24, 26 respectively; but each battery cell group may contain either more or less than four series-connected battery cell sub-groups. As yet another example, Figure 4 shows two parallel-connected battery cells in each battery cell sub-group, but each battery cell sub-group may contain more than two parallel-connected battery cells.