WO2018160829A1

WO2018160829A1 - Vehicle battery pack including structural features for reducing size and improving ease of assembly

Info

Publication number: WO2018160829A1
Application number: PCT/US2018/020442
Authority: WO
Inventors: Tyler David COLLINS; Timothy Hughes
Original assignee: Gentherm Inc.
Priority date: 2017-03-03
Filing date: 2018-03-01
Publication date: 2018-09-07

Abstract

A battery pack includes an outer housing, a cell stack, and an insulator. The outer housing includes a bottom wall and a first sidewall. The first sidewall has a lower end and an upper end that is oriented at one of an inward angle and an outward angle relative to the lower end. The cell stack includes a plurality of battery cells. The insulator is configured to fit around and electrically insulate an outer side surface of the cell stack. An inner surface of the insulator is configured to face the outer side surface of the cell stack. An outer surface of the insulator is configured to face an inner surface of the first sidewall of the outer housing. At least a portion of the outer surface of the insulator is tapered to match the one of the inward angle and the outward angle of the first sidewall.

Description

VEHICLE BATTERY PACK INCLUDING STRUCTURAL FEATURES FOR REDUCING SIZE AND IMPROVING EASE OF ASSEMBLY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 62/466,936, filed on March 3, 2017. The entire disclosure of the above applications is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to vehicle battery packs including structural features for reducing size, improving ease of assembly, and relaxing dimension tolerances.

BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] Referring now to FIGS. 1 -4, a battery pack 10 according to the prior art is configured to produce 48 volts (V), or a voltage within a predetermined range of 48 V, and is configured to be installed in a vehicle. The battery pack 10 includes a battery cell subassembly 12, a cooling subassembly 14, an outer housing 16, a top cover 18, a vent tube 19 extending through the cover 18, main terminals or connectors 20, a communication connector 22, a first circuit 24, and a second circuit 26. As best shown in FIG. 4, the battery cell subassembly 12 includes a first cell stack 28, a second cell stack 30, first insulators 32, second insulators 34, and a sub frame 36. Each of the first and second cell stacks 28 and 30 includes a plurality of battery cells 38 and sheet insulators 40 separating the battery cells 38 and electrically insulating the battery cells 38 from one another. Each of the battery cells 38 is a lithium ion prismatic battery cell. Each of the sheet insulators 40 fits over three sides of one of the battery cells 38. In addition, each of the sheet insulators 40 are coated with adhesive so that the sheet insulators 40 can be used to permanently join the battery cells 38 to one another while the battery cell subassembly 12 is assembled.

[0005] Each of the first insulators 32 cooperate with a corresponding one of the second insulators 34 to electrically insulate the outer side surfaces of the corresponding one of the first and second cell stacks 28 and 30. In this regard, the first and second insulators 32 and 34 are formed from an electrically insulating material such as plastic. Each of the first insulators 32 fits over one end of one of the first and second cell stacks 28 and 30, and each of the second insulators 34 fits over the opposite end of one of the first and second cell stacks 28 and 30. The first and second insulators 32 and 34 are joined to the outer side surfaces of the first and second cell stacks 28 and 30 using adhesive. Each of the first and second insulators 32 and 34 includes three sidewalls with an outer surface 42 and an inner surface 44 that are parallel to one another and are flat.

[0006] Each of the first insulators 32 is configured to overlap a corresponding one of the second insulators 34 when the first and second insulators 32 and 34 are assembled together around a corresponding one of the first and second cell stacks 28 and 30. In this regard, each of the second insulators 34 has an indentation or groove 46 in the outer surface thereof, and each of the first insulators 32 has an indentation or groove 48 in an inner surface thereof. The grooves 46, 48 have a complementary shape so that the outer surfaces of the first and second insulators 32 and 34 are flush with one another and the inner surfaces of the insulators 32, 34 are flush with one another. Each of the first and second insulators 32 and 34 further includes a bottom ledge 50 configured to support a corresponding one of the first and second cell stacks 28 and 30.

[0007] The sub frame 36 fits over the first and second cell stacks 28 and 30 and the first and second insulators 32 and 34 holds the cell stacks 28, 30 and the insulators 32, 34 together. The sub frame 36 includes a pair of side plate assemblies 52, a pair of end plates 54, and a divider plate 56. Each of the side plate assemblies 52 includes a pair of plates 58 that are integrally formed with one another as a single component. The side plate assemblies 52, the end plates 54, and the divider plate 56 are formed separately and then joined together. Each of the side plate assemblies 52, the end plates 54, and the divider plate 56 is fabricated (e.g., extruded, stamped, machined) from metal (e.g., aluminum, steel). [0008] Before joining the side plate assemblies 52, the end plates 54, and the divider plate 56 together, these components are placed around the first and second cell stacks 28 and 30 and the first and second insulators 32 and 34. A fixture is then used to position these components relative to one another and to apply a compressive force on the outer surfaces of the side plate assemblies 52 and the end plates 54 to clamp the first and second cell stacks 28 and 30. The side plate assemblies 52, the end plates 54, and the divider plate 56 are then welded to one another to form welded lap joints 60. Alternatively, the side plate assemblies 52, the end plates 54, and the divider plate 56 may be spot welded to one another or bonded to one another using adhesive. In addition, the sub frame 36 includes hollow bosses 61 at the four outer corners thereof for receiving fasteners 62 that fasten the sub frame 36 to the outer housing 16.

[0009] As best shown in FIGS. 1 and 2, the cooling subassembly 14 includes an inlet port 63, an outlet port 64, and a liquid flow path 66 that is disposed below the battery cell subassembly 12. Liquid flowing through the cooling subassembly 14 absorbs heat from the battery cell subassembly 12. In this regard, the cooling subassembly 14 acts as a heat exchanger.

[0010] The outer housing 16 includes four sidewalls 68, a bottom floor 70, and mounting brackets 71 that are integrally formed as a single component. The outer housing 16 and the cover 18 cooperate with one another to enclose and protect the battery cell subassembly 12 and the cooling subassembly 14. The cover 18 is joined to the outer housing 16 using fasteners 72, and a gasket 74 (FIG. 3) is disposed between the cover 18 and the outer housing 16 to provide a seal therebetween. Thus, the interior space defined by the outer housing 16 and the cover 18 is completely sealed except for the vent tube 19. However, the vent tube 19 may be sealed using a rupture or burst disc to completely seal the interior space defined by the outer housing 16 and the cover 18. The sub frame 36 is joined to the outer housing 16 using the fasteners 62, which extend through the hollow bosses 61 in the sub frame 36 and into the bottom floor 70 of the outer housing 16. The mounting brackets 71 are for mounting the battery pack 10 in a vehicle. [0011] Each of the outer housing 16 and the cover 18 is casted from metal. Due to a draft angle required to withdraw the outer housing 16 from a casting die, upper ends 68a of the sidewalls 68 of the outer housing 16 are angled outward (i.e., in a direction away from the interior of the outer housina 16). In other words, the upper ends 68a of the sidewalls 68 are dispose further outward than lower ends 68b of the sidewalls 68. Thus, the sidewalls 68 of the outer housing 16 are angled with respect to the side plate assemblies 52 and the end plates 54 of the sub frame 36. Therefore, as best shown in FIG. 3, there is a gap 76 between the outer surface of the battery cell subassembly 12 and the inner surface of the outer housing 16 to accommodate the draft angle of the outer housing 16. In addition, the gap 76 accommodates the welded lap joints 60 and the hollow bosses 61 on the sub frame 36.

[0012] The first circuit 24 electrically connects the battery cells 38 to one another in series. The first circuit 24 includes a plurality of busbars 78 and a fuse circuit protector 80. The busbars 78 are laser welded to terminals of the battery cells 38. Each of the busbars 78 electrically connects a positive terminal of one of the battery cells 38 to a negative terminal of an adjacent one of the battery cells 38 to electrically connect the battery cells 38 in series or in a combination of series and parallel. The first circuit 24 also includes a power management module 82 and a thermal management module 84. The power management module 82 controls the amount of power flowing to and from the battery cells 38. The thermal management module 84 controls the temperature of the battery cells 38 by controlling the amount of power supplied to thermoelectric devices (TEDs) in the cooling subassembly 14.

[0013] The second circuit 26 electrically connects the first circuit 24 to the main terminals 20 of the battery pack 10. The second circuit 26 includes a pair of wires 86, a pyroswitch 48 V circuit protector 88, a contactor or relay 90, and a current sensing precision resistor or shunt 92. The circuit protector 88, the relay 90, and the current sensing precision resistor 92 are disposed at one end of the battery pack 10. The power management module 82 controls the relay 90 to allow or prevent current flow to the main terminals 20.

SUMMARY

[0014] A battery pack according to the present disclosure includes an outer housing, a battery cell subassembly, and a cover. The outer housing includes a bottom wall and a first sidewalk The first sidewall has a lower end and an upper end that is oriented at one of an inward angle and an outward angle relative to the lower end. The battery cell subassembly includes at least one cell stack and at least one insulator. The at least one cell stack has an outer side surface and includes a plurality of battery cells. The at least one insulator is configured to fit around the outer side surface of the at least one cell stack to electrically insulate the outer side surface. The at least one insulator has an inner surface and an outer surface. The inner surface of the at least one insulator is configured to face the outer side surface of the at least one cell stack. The outer surface of the at least one insulator is configured to face an inner surface of the first sidewall of the outer housing. At least a portion of the outer surface of the at least one insulator is tapered to match the one of the inward angle and the outward angle of the first sidewall of the outer housing. The cover is configured to fit over the outer housing. The outer housing and the cover cooperate with one another to enclose the battery cell subassembly.

[0015] In one example, the outer housing includes a center housing and a base, the center housing includes the first sidewall, the base includes the bottom wall and a second sidewall extending from the bottom wall and configured to be joined to the lower end of the first sidewall. Also, in this example, the outer surface of at least one insulator includes a first portion and a second portion, the first portion of the outer surface is configured to face the inner surface of the first sidewall and is tapered to match the one of the inward angle and the outward angle of the first sidewall, and the second portion of the outer surface is configured to face an inner surface of the second sidewall. [0016] In one example, the upper end of the first sidewall of the center housing is oriented at the inward angle relative to the lower end of the first sidewall, and the first portion of the outer surface of the at least one insulator is tapered to match the inward angle of the first sidewall.

[0017] In one example, the second sidewall has a lower end and an upper end that is oriented at the outward angle relative to the lower end of the second sidewall, and the second portion of the outer surface of the at least one insulator is tapered to match the outward angle of the second sidewall.

[0018] In one example, the at least one insulator includes a one-piece insulator, and the first and second portions of the outer surface of the at least one insulator are both disposed on the one-piece insulator.

[0019] In one example, the at least one insulator includes an upper insulator and a lower insulator, the first portion of the outer surface of the at least one insulator is disposed on the upper insulator, and the second portion of the outer surface of the at least one insulator is disposed on the lower insulator.

[0020] In one example, the lower insulator includes a bottom ledge projecting from the inner surface thereof, the bottom ledge is configured to support the at least one cell stack, the upper insulator includes a top ledge projecting from the inner surface thereof, and the top ledge is configured to cooperate with the bottom ledge to capture the at least one cell stack.

[0021] In one example, the battery pack further includes a cooling subassembly that includes an inlet port, an outlet port, the base, a liquid flow path, and a cover. The liquid flow path is configured to allow liquid to absorb heat from the battery cell subassembly as the liquid flows through the liquid flow path from the inlet port to the outlet port. A bottom surface of the base seals a top of the liquid flow path. A top surface of the cover seals a bottom of the liquid flow path.

[0022] In one example, when the battery cell subassembly is disposed within the outer housing, the outer surface of the at least one insulator and the inner surface of the outer housing are separated by a uniform gap.

[0023] In one example, the at least one insulator includes a plurality of ribs disposed on the outer surface thereof, and the plurality of ribs are configured to contact the inner surface the outer housing to secure the at least one insulator and the at least one cell stack within the outer housing.

[0024] In one example, the at least one insulator includes a bottom ledge and a top ledge projecting from the inner surface of the at least one insulator. The bottom ledge is configured to support the at least one cell stack. The top ledge is configured to cooperate with the bottom ledge to capture the at least one cell stack. [0025] In one example, the at least one cell stack includes a first cell stack and a second cell stack, and the at least one insulator includes first, second, and third insulators. The first insulator is configured to fit around the outer side surface of the first cell stack. The second insulator is configured to fit around the outer side surface of the second cell stack. The third insulator is configured to fit between the first and second cell stacks. [0026] In one example, the battery pack further includes a first circuit, a second circuit, and a main terminal. The first circuit is configured to electrically connect the plurality of battery cells to one another. The second circuit is configured to electrically connect the first circuit to the main terminal. The second circuit is disposed within the cover. [0027] A second battery pack according to the present disclosure includes an outer housing, a battery cell subassembly, and a cover. The outer housing includes a bottom wall and a first sidewall. The first sidewall has a lower end and an upper end. The battery cell subassembly includes at least one cell stack and at least one insulator. The at least one cell stack has an outer side surface and includes a plurality of battery cells. The at least one insulator is configured to fit around the outer side surface of the at least one cell stack to electrically insulate the outer side surface. The at least one insulator has an inner surface and an outer surface. The inner surface of the at least one insulator is configured to face the outer side surface of the at least one cell stack. The outer surface of the at least one insulator is configured to face an inner surface of the first sidewall of the outer housing. The at least one insulator includes a first plurality of ribs disposed on the outer surface thereof. The first plurality of ribs are configured to contact the inner surface of the first sidewall of the outer housing to secure the at least one insulator and the at least one cell stack within the outer housing. The cover is configured to fit over the outer housing. The outer housing and the cover cooperate with one another to enclose the battery cell subassembly.

[0028] In one example, the at least one insulator and the at least one cell stack are secured within the outer housing solely by the contact between the first plurality of ribs and the inner surface of the first sidewall of the outer housing.

[0029] In one example, when the battery cell subassembly is disposed within the outer housing, the outer surface of the at least one insulator and the inner surface of the outer housing are separated by a gap other than at locations where the first plurality of ribs contact the inner surface of the first sidewall of the outer housing. Also, in this example, when the first plurality of ribs are in an uncompressed state, the first plurality of ribs project from the outer surface of the at least one insulator by an amount that is greater than a size of the gap between the outer surface of the at least one insulator and the inner surface of the outer housing. [0030] In one example, the upper end of the first sidewall of the outer housing is angled inward relative to the lower end of the first sidewall, and at least a portion of the outer surface of the at least one insulator is tapered to match the inward angle of the first sidewall. [0031] In one example, the outer housing includes a center housing and a base, the center housing includes the first sidewall, the base includes the bottom wall and a second sidewall extending from the bottom wall and configured to be joined to the lower end of the first sidewall. Also, in this example, the outer surface of at least one insulator includes a first portion and a second portion, the first portion of the outer surface is configured to face the inner surface of the first sidewall and is tapered to match the inward angle of the first sidewall, the second portion of the outer surface is configured to face the inner surface of the second sidewall, and the first plurality of ribs are disposed on the first portion of the outer surface.

[0032] In one example, the second sidewall has a lower end and an upper end that is angled outward relative to the lower end of the second sidewall, and the second portion of the outer surface of the at least one insulator is tapered to match the outward angle of the second sidewall.

[0033] In one example, the at least one insulator includes a second plurality of ribs disposed on the inner surface of the at least one insulator and configured to contact the outer side surface of the at least one cell stack to secure the at least one cell stack within the at least one insulator.

[0034] A third battery pack according to the present disclosure includes an outer housing, a battery cell subassembly, and a cover. The outer housing includes a center housing and a base. The center housing includes a first plurality of sidewalls having a lower end and an upper end that is angled inward relative to the lower end thereof. The base including a bottom wall and a second plurality of sidewalls having a lower end and an upper end that is angled outward relative to the lower end thereof. The second plurality of sidewalls extend from the bottom wall and are configured to be joined a lower end of the center housing. The battery cell subassembly includes a first cell stack including a first plurality of battery cells, a second cell stack including a second plurality of battery cells, a first insulator configured to fit around the first cell stack, and a second insulator configured to fit around the second cell stack. Each of the first and second insulators have an outer surface with a first portion that is tapered to match the inward angle of the first plurality of sidewalls of the center housing and a second portion that is tapered to match the outward angle of the second plurality of sidewalls of the base. Each of the first and second insulators including a first plurality of ribs disposed on the first portion of the outer surface thereof. The first plurality of ribs on the first and second insulators are configured to contact an inner surface of the center housing to secure the first and second insulators and the first and second cell stacks within the outer housing. The cover is configured to fit over the outer housing. The outer housing and the cover cooperate with one another to enclose the battery cell subassembly. [0035] In one example, when the battery cell subassembly is disposed within the outer housing, the outer surface of each of the first and second insulators and the inner surface of the outer housing are separated by a uniform gap other than at locations where the first plurality of ribs contact the inner surface of the outer housing.

[0036] In one example, each of the first and second insulators includes a second plurality of ribs disposed on an inner surface thereof. The second plurality of ribs on the inner surface of the first insulator is configured to contact an outer side surface of the first cell stack to secure the first cell stack within the first insulator. The second plurality of ribs on the inner surface of the second insulator is configured to contact an outer side surface of the second cell stack to secure the second cell stack within the second insulator.

[0037] In one example, each of the first and second insulators has an inner surface with a first portion that is tapered to match the taper of the first portion of the outer surface thereof and a second portion that is tapered to match the taper of the second portion of the outer surface thereof. [0038] In one example, each of the first and second insulators includes an upper insulator piece and a lower insulator piece that is separate from the upper insulator piece, the upper insulator pieces have outer surfaces that forms the first portions of the outer surfaces of the first and second insulators, the lower insulator pieces have outer surfaces that forms the second portions of the outer surfaces of the first and second insulators, the first plurality of ribs extend vertically on the outer surfaces of the upper and lower insulator pieces, and the second plurality of ribs extend vertically on inner surfaces of the upper and lower insulator pieces. [0039] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0041] FIGS. 1 and 2 are perspective views of the battery pack according to the prior art with a portion of a housing of the battery pack removed; [0042] FIG. 3 is a top view of the battery pack of FIGS. 1 and 2 with a cover of the battery pack removed;

[0043] FIG. 4 is an exploded perspective view of a battery cell subassembly within the battery pack of FIGS. 1 and 2;

[0044] FIG. 5 is a perspective view of a battery pack according to the present disclosure;

[0045] FIG. 6 is a perspective view of the battery pack of FIG. 5 with a cover of the battery pack exploded from the remainder of the battery pack;

[0046] FIG. 7 is a bottom perspective view of the cover of the battery pack of FIG. 5;

[0047] FIG. 8 is a top view of the battery pack of FIG. 5 with the cover removed; [0048] FIG. 9 is a section view of the battery pack of FIG. 5 taken along a line 9 - 9 shown in FIG. 5;

[0049] FIG. 10 is an exploded perspective view of a battery cell subassembly and a center housing of the battery pack of FIG. 5;

[0050] FIG. 1 1 is a perspective view of a portion of the battery pack of FIG. 5 illustrating a rib on an outer surface of the battery cell subassembly;

[0051] FIG. 12 is an exploded top perspective view of a cooling subassembly of the battery pack of FIG. 5;

[0052] FIG. 13 is an exploded bottom perspective view of the cooling assembly of the battery pack of FIG. 5; [0053] FIG. 14 is an perspective view of another battery pack according to the present disclosure;

[0054] FIG. 15 is an exploded perspective view of the battery pack of FIG. 14;

[0055] FIG. 16 is a perspective view of the battery pack of FIG. 14 with a cover of the battery pack removed and a cooling assembly of the battery pack removed;

[0056] FIG. 17 is a section view of the portion of the battery pack shown in FIG. 16 taken along a line 17 - 17 shown in FIG. 16;

[0057] FIG. 18 is a section view of the portion of the battery pack shown in FIG. 16 taken along a line 18 - 18 shown in FIG. 16; [0058] FIG. 19 is an exploded perspective view of a portion of the battery pack of FIG. 14 including a battery cell subassembly and a center housing;

[0059] FIG. 20 is a top view of the battery cell subassembly and the center housing shown in FIG. 19 assembled together;

[0060] FIG. 21 is an enlarged portion of FIG. 20 within a circle 21 illustrating a compressed rib on an outer surface of the battery cell subassembly; and

[0061] FIGS. 22-27 are perspective and end views of an insulator assembly that may be incorporated in the battery pack of FIGS. 1 and 2 or the battery pack of FIG. 14.

[0062] In the drawings, reference numbers may be reused to identify similar and/or identical elements. DETAILED DESCRIPTION

[0063] Referring now to FIGS. 5-13, a battery pack 100 according to the present disclosure is configured to produce a voltage such as 48 volts (V), or a voltage within a predetermined range of 48 V, and is configured to be installed in a vehicle. The battery pack 100 includes a battery cell subassembly 102, a cooling subassembly 104, an outer housing 106, a top cover 108, a vent tube 109 extending through the cover 108, main connectors or terminals 120, a communication connector 122, a first circuit 124, and a second circuit 126 (FIG. 7). As best shown in FIG. 10, the battery cell subassembly 102 includes a first cell stack 128, a second cell stack 130, a first insulator 132, and a second insulator 134, and a third insulator 136. Each of the first and second cell stacks 128 and 130 includes a plurality of battery cells 138 and sheet insulators 140 separating the battery cells 138 and electrically insulating the battery cells 138 from one another. Each of the battery cells 138 is a lithium ion prismatic battery cell that produces 2.4 V. Each of the sheet insulators 140 fits over three sides of one of the battery cells 138. In addition, each of the sheet insulators 140 are coated with adhesive so that the sheet insulators 140 can be used to permanently join the battery cells 138 to one another while the battery cell subassembly 102 is assembled.

[0064] The first, second, and third insulators 132, 134, and 136 cooperate with one another to electrically insulate the outer side surfaces of the first and second cell stacks 128 and 130. In this regard, the first, second, and third insulator 132, 134, and 136 are formed from an electrically insulating material such as plastic. The first insulator 132 fits over three sides of one of the first and second cell stacks 128 and 130, the second insulator 134 fits over three sides of the other one of the cell stacks 128, 130, and the third insulator 136 is dispose between the cell stacks 128, 130. The first, second, and third insulators 132, 134, and 136 are joined to the outer side surfaces of the first and second cell stacks 128 and 130 using adhesive. Each of the first and second insulators 132 and 134 includes three sidewalls with an outer surface 142 and an inner surface 144. The third insulator 136 may be a thin sheet of plastic covered by adhesive.

[0065] The first insulator 132 is configured to overlap the second insulator 134 when the first and second insulators 132 and 134 are assembled together around the first and second cell stacks 128 and 130. In this regard, the overlapping ends of the first and second insulators 132 and 134 may include complementary indentations or grooves similar to the grooves 46, 48 so that the outer surfaces of the insulators 132, 134 are flush with one another and the inner surfaces of the insulators 132, 134 are flush with one another. Each of the first and second insulators 132 and 134 includes a plurality of ribs 146 on the outer surface 142 thereof, a bottom ledge 150 configured to support a corresponding one of the first and second cell stacks 128 and 130, and a top ledge 152 configured to cooperate with the bottom ledge 150 to capture the cell stacks 128, 130.

[0066] As best shown in FIGS. 6, 9, 12 and 13, the cooling subassembly 104 includes an inlet port 163, an outlet port 164, a cold plate base 166, TEDs 168, a heat distribution plate 170, fasteners 171 , a liquid flow path 172, and a cold plate cover 174. The cold plate base 166, the TEDs 168, the heat distribution plate 170, and the liquid flow path 172 are disposed below the battery cell subassembly 102. Liquid flowing through the cooling subassembly 104 absorbs heat from the battery cell subassembly 102. In this regard, the cooling subassembly 104 acts as a heat exchanger. In addition, when voltage is applied to the TEDs 168, the TEDs 168 generate a temperature difference between the side of the TEDs 168 facing the battery cell subassembly 102 and the opposite side of the TEDs 168. Thus, the TEDs can also be used to absorb heat from the battery cell subassembly 102.

[0067] The heat distribution plate 170 is disposed between the TEDs 168 and the battery subassembly 102. The heat distribution plate 170 can be formed (e.g., stamped, cased, extruded) from metal (e.g., aluminum, steel). The fasteners 171 secure the heat distribution plate 170 and the TEDs 168 to the cold plate base 166. [0068] The liquid flow path 172 is formed by a bottom surface 176 of the cold plate base 166, a perimeter wall 178, a divider wall 180, a plurality of fins 182, and a top surface 184 of the cold plate cover 174. In other words, the bottom surface 176 of the cold plate base 166 seals the top of the liquid flow path 172, and the top surface 184 of the cold plate cover 174 seals the bottom of the liquid flow path 172. As liquid flows through liquid flow path 172 from the inlet port 163 to the outlet port 164, the liquid is guided past the fins 182 and is directed to flow in a path corresponding to the entire bottom surface of the battery cell subassembly 102.

[0069] As best shown in FIGS. 5, 6, and 9, the cold plate base 166 forms the bottom wall of the outer housing 106. In addition to the cold plate base 166, the outer housing 106 includes a center housing 186. The center housing 186 includes four sidewalls 188 that are integrally formed as a single component. The center housing 186 is joined to the cold plate base 166 using fasteners 190, and a gasket or sealant 192 (FIG. 12) is disposed between the center housing 186 and the cold plate base 166 to provide a seal therebetween. [0070] The outer housing 106 and the cover 108 cooperate with one another to enclose and protect the battery cell subassembly 102 and the cooling subassembly 104. The cover 108 is joined to the center housing 186 of the outer housing 106 using fasteners 194, and a gasket or sealant 196 (FIG. 8) is disposed between the cover 108 and the center housing 186 to provide a seal therebetween. Thus, the interior space defined by the outer housing 106 and the cover 108 is completely sealed except for the vent tube 109. However, the vent tube 109 may be sealed using a rupture or burst disc to completely seal the interior space defined by the outer housing 106 and the cover 108.

[0071] Each of the cold plate base 166, the center housing 186, and the cover 108 is casted from a metal such as aluminum. In addition, each of these components is casted as a monolithic piece. Due to a draft angle required to withdraw the cold plate base 166 from a casting die, an upper end 166a of the cold plate base 166 is angled outward (i.e., in a direction away from the interior of the cold plate base 166) relative to a lower end 166b of the cold plate base 166. Conversely, due to a draft angle required to withdraw the center housing 186 from a casting die, an upper end 186a of the center housing 186 is angled inward relative to a lower end 186b of the center housing 186.

[0072] In contrast to the outer and inner surfaces 42, and 44 of the first and second insulators 32 and 34, the outer and inner surfaces 142 and 144 of the first and second insulators 132 and 134 are not parallel to each other. Rather, as best shown in FIG. 9, the inner surface 144 is vertical and flat so that the insulators 132, 134 sit flush against the outer surfaces of the battery cells 138, and the outer surface 142 is oriented at multiple angles with respect to the inner surface 144. A first portion 142a of the outer surface 142 is tapered or oriented at an angle that matches or complements the draft angle of the center housing 186, and a second portion 142b of the outer surface 142 is oriented at an angle that matches or complements the draft angle of the cold plate base 166. Thus, the outer surface portion 142a of the insulators 132, 134 sits flush against an inner surface 200 of the center housing 186, and the outer surface portion 142b of the insulators 132, 134 sits flush against an inner surface 198 of the cold plate base 166.

[0073] Since the outer surface 142 of each of the first and second insulators 132 and 134 is tapered to complement or match the draft angle of the center housing 186, the gap between the outer surface 142 of the battery cell subassembly 102 and the inner surface 200 of the center housing 186 may be substantially reduced or eliminated. The gap may be uniform across the entire interface between the outer surface 142 of the battery cell subassembly 102 and the inner surface 200 of the center housing 186, and may be sized to accommodate adhesive. In one example, the gap between the outer surface 142 of the battery cell subassembly 102 and the inner surface 200 of the center housing 186 is within a range from 0.001 inches (in.) to 0.010 in. [0074] As indicated above, adhesive may be applied to the outer surface 142 of the battery cell subassembly 102 and/or the inner surface 200 of the center housing 186 to strengthen the joint between the battery cell subassembly 102 and the center housing 186. If adhesive was applied to this interface without tapering the outer surface 142 of the battery cell subassembly 102, the adhesive would be squeezed out of this interface as the center housing 186 is inserted over the battery cell subassembly 102. In contrast, since the outer surface 142 of the battery cell subassembly 102 is tapered, there is initially a wide gap between these two components as the center housing 186 is inserted over the battery cell subassembly 102. While this gap gradually decreases as the center housing 186 is inserted further over the battery cell subassembly 102, this gap does not fall below a minimum value even when these two components are fully assembled due to the presence of the ribs 146. This ensures that adhesive is not squeezed out of the interface between these two components during assembly.

[0075] In addition, since the outer surface 142 of each of the first and second insulators 132 and 134 is angled to complement the draft angle of the center housing 186, the center housing 186 is joined to the battery cell subassembly 102 via a tapered fit. Further, the ribs 146 on the outer surfaces 142 of the first and second insulators 132 and 134 are compressed by the center housing 186 as the center housing 186 is inserted over the battery cell subassembly 102. Thus, there is no gap between the outer surface 142 of the battery cell subassembly 102 and the inner surface 200 of the center housing 186 where the ribs 146 contact the inner surface 200 of the center housing 186, which strengthens the tapered fit. Moreover, the amount by which the ribs 146 project from the outer surfaces 142 of the first and second insulators 132 and 134 is greater than the size of the gap between the outer surface 142 of the battery cell subassembly 102 and the inner surface 200 of the center housing 186. Thus, the contact between the ribs 146 on the first and second insulators 132 and 134 and the inner surface 200 of the center housing 186 yields an interference fit between the center housing 186 and the battery cell subassembly 102. The ribs 146 also ensure that the gap between the battery cell subassembly 102 and the center housing 186 is uniform across the entire interface between these two components by absorbing the manufacturing tolerances of these two components, which further ensures that adhesive is not squeezed out of this interface during assembly. In various implementations, adhesive may not be applied to the outer surface 142 of the battery cell subassembly 102 or the inner surface 200 of the center housing 186. In these implementations, the battery cell sub assembly 102 may be secured within the outer housing 106 solely by the interference fit between the center housing 186 and the battery cell subassembly 102 provided by the ribs 146. [0076] Due to the tapered and interference fit, the center housing 186 holds the battery cell subassembly 102 together and holds the battery cell subassembly 102 tightly within the outer housing 106 when the center housing 186 is place around the battery cell subassembly 102. As a result, there is no need for a sub frame, such as the sub frame 36, to hold the battery cell subassembly 102 together. Eliminating the sub frame improves the ease of assembling the battery pack 100 since there is no need to locate the components of the sub frame around the battery cell subassembly 102 and to weld the components together. Instead, the center housing 186 is simply inserted over one end of the battery pack 100. In addition, since the welding operation is eliminated, the tolerance stack up associated with the welding operation may be avoided, which enables the gap between the center housing 186 and the battery cell subassembly 102 to be further reduced. Further, eliminating the sub frame enables the size of the battery pack 100 to be reduced by the amount of space that would otherwise be required to accommodate the sub frame.

[0077] Moreover, since the center housing 186 holds the battery cell subassembly 102 tightly within the outer housing 106, there is no need for fasteners that attach the battery cell subassembly 102 to the outer housing 106. Thus, the fasteners (e.g., the fasteners 62) and the hollow bosses that receive the fasteners (e.g., the hollow bosses 61 ) may also be eliminated. This enables the size of the gap between the outer surface 142 of the battery cell subassembly 102 and the inner surface 200 of the center housing 186 to be substantially reduced or eliminated.

[0078] As best shown in FIGS. 6, 7, and 9, the first circuit 124 electrically connects the battery cells 138 to one another in series. The first circuit 124 includes a plurality of busbars 204 and a pair of contacts 206 in the form of rectangular conductive plates. The busbars 204 are laser welded to terminals of the battery cells 138. Each of the busbars 204 electrically connects a positive terminal of one of the battery cells 138 to a negative terminal of an adjacent one of the battery cells 138 to electrically connect the battery cells 138 in series. The first circuit 124 also includes a power management module 208 and a thermal management module 210. The power management module 208 controls the amount of power flowing to and from the battery cells 138. The thermal management module 210 controls the temperature of the battery cells 138 by controlling the amount of power supplied to the TEDs 168 in the cooling subassembly 104. [0079] The second circuit 126 electrically connects the first circuit 124 to the main terminals 120 of the battery pack 100. The second circuit 126 includes a pair of spring- loaded connectors 212, a fuse circuit protector 214, a contactor or relay 216, a pyroswitch circuit protector 218, and a current sensing precision resistor 220. The power management module 208 controls the relay 216 to adjust the amount of power flowing to and from the battery cells 138. The spring-loaded connectors 212, the fuse circuit protector 214, the relay 216, the pyroswitch circuit protector 218, and the current sensing precision resistor 220 are disposed within the cover 108 rather than at one end of the battery pack 10. Thus, a length L of the battery pack 100 may be reduced relative to the battery pack 10. [0080] As the cover 108 is placed onto the center housing 186, the spring-loaded connectors 212 of the second circuit 126 fit over the contacts 206 of the first circuit 124 as shown in FIG. 10 to electrically connect the first and second circuits 124 and 126 to one another. Thus, there is no need for wires, such as the wires 86, to electrically connect the first and second circuits 124 and 126 to one another. This further improves the ease of assembling by eliminating a wire connection step that would otherwise be required. In addition, the size of the battery pack 100 may be further reduced by the amount of space that would otherwise be required to accommodate the wires.

[0081] Referring now to FIGS. 14 through 21 , another battery pack 250 according the present disclosure is shown which is configured to produce a voltage such as 48 V, or a voltage within a predetermined range of 48 V, and is configured to be installed in a vehicle. The battery pack 250 is substantially similar to the battery pack 100, and therefore the focus of the following discussion will be on the differences between the battery packs 100, 250. In addition, FIGS. 14 through 21 illustrate some features of the battery pack 250 in more detail relative to the level of detail that FIGS. 5 through 13 illustrate similar features on the battery pack 100, and therefore those features will be discussed as well. The battery pack 250 includes a battery cell subassembly 252, a cooling subassembly 254, an outer housing 256, a top cover 258, the vent tube 109, the main terminals 120, the communication connector 122, the first circuit 124, and the second circuit 126. Like the outer housing 106 of the battery pack 100, the outer housing 256 includes a center housing 260 and a cold plate base 262.

[0082] The battery cell subassembly 252 is substantially similar to the battery cell subassembly 102 except that the battery cell subassembly 252 includes a battery cell 264 in addition to the battery cells 138 (i.e., the battery cell subassembly 252 includes one more battery cell than the battery cell subassembly 102). Thus, a length L of the cold plate base 262, the center housing 260, and the cover 258 is increased relative to the length L of the cold plate base 166, the center housing 186, and the cover 108, respectively, to accommodate the battery cell 264. In addition, the battery cell subassembly 252 includes a second insulator 266 that has a modified shape relative to the second insulator 134 to accommodate the battery cell 264. To this end, as best shown in FIG. 20, the second insulator 266 includes a rectangular step-out portion 268 in which the battery cell 264 is disposed.

[0083] Like the battery cell subassembly 102 of the battery pack 100, the ribs 146 are disposed on the outer surface 142 of the battery cell subassembly 252. Notably, FIG. 21 shows one of the ribs 146 on the outer surface 142 of the battery cell subassembly 252 in a compressed state. In addition, a dashed line represents the shape of the ribs 146 in an uncompressed state. Thus, FIG. 21 clearly illustrates the interference fit between the outer surface 142 of the battery cell subassembly 252 and the inner surface 200 of the center housing 260. In addition, the gap between the outer surface 142 of the battery cell subassembly 252 and the inner surface 200 of the center housing 260 is labelled 270 in FIG. 21 . As discussed above, the gap 270 may be sized to accommodate adhesive, and may be within a range from 0.001 in. to 0.010 in. In addition, there is no gap between the outer surface 142 of the battery cell subassembly 252 and the inner surface 200 of the center housing 260 where the ribs 146 on the outer surface 142 of the battery cell subassembly 252 contact the inner surface 200 of the center housing 260.

[0084] Once the battery cell subassembly 252 is fully assembled, the center housing 260 is inserted over the battery cell assembly 252 in a direction 272 (FIG. 19) until a ledge 274 on the center housing 260 contacts the ledges 152 on the first and second insulators 132 and 266 as shown in FIGS. 17 and 18. In this regard, the ledges 152, 274 serve as abutments or stops which locate the center housing 260, the first and second insulators 132 and 266, the first and second cell stacks 128 and 130, and the battery cell 264 relative to each other. Thus, the ledges 152, 274 provide aid in assembling the battery pack 250 and control the dimensions of the battery pack 250.

[0085] Referring now to FIGS. 22-27, an insulator assembly 276 may be used in place of each of the first and second insulators 132 and 134 of the battery pack 102 shown in FIGS. 5-13 and in place of the first insulator 132 of the battery pack 250 shown in FIGS. 14-21 . The insulator assembly 276 may also be used in place of the second insulator 266 of the battery pack 250 provided that the shape of insulator assembly 276 is modified to accommodate the additional battery cell 264 (FIG. 20) included in the battery pack 250. For example, to accommodate the battery cell 264, the insulator assembly 276 may be modified to include a rectangular step-out portion similar to the rectangular step-out portion 268 (FIG. 20) of the second insulator 266.

[0086] The insulator assembly 276 includes an upper insulator 278 and a lower insulator 280. The upper insulator 278 includes three sidewalls with an inner surface 282 and an outer surface 284, a plurality of ribs 286 disposed on the inner surface 282, a plurality of ribs 288 disposed on the outer surface 284, and a top ledge 290 projecting from the inner surface 282. The ribs 286 on the inner surface 282 and the ribs 288 on the outer surface 284 extend vertically from a lower end 292 of the upper insulator 278 to an upper end 294 of the upper insulator 278.

[0087] The lower insulator 280 includes three sidewalls with an inner surface 296 and an outer surface 298, a plurality of ribs 300 disposed on the inner surface 296, a plurality of ribs 302 disposed on the outer surface 298, and a bottom ledge 304 projecting from the inner surface 296. The ribs 300 on the inner surface 296 and the ribs 300 on the outer surface 298 extend vertically from a lower end 306 of the lower insulator 280 to an upper end 308 of the lower insulator 280. [0088] The bottom ledge 304 of the lower insulator 280 is configured to support one of the first and second cell stacks 128 and 130 (FIG. 10). The top ledge 290 is configured to cooperate with the bottom ledge 150 to capture the cell stacks 128, 130. Since the upper and lower insulators 278 and 280 are separate pieces, the upper and lower insulators 278 and 280 can move relative to one another - within the confines of the outer housing 106 (FIG. 9) - and thereby absorb the tolerance stack up (e.g., dimensional variations) of the cell stacks 128, 130. In addition, as best shown in FIG. 25, the top ledge 290 has a top surface 310, a bottom surface 312, a rib 314 projecting from the top surface 310, and a notch 316 extending into the bottom surface 312. Due to the presence of the notch 316, the portion of the top ledge 290 disposed above the notch 316 acts as a living hinge, which allows the top ledge 290 to move vertically and improves the ability of the insulator assembly 276 to absorb the tolerance stack up of the cell stacks 128, 130. The rib 314 on the top surface 310 of the top ledge 290 limits the upward movement of the top ledge 290.

[0089] As best shown in FIG. 26, the outer surface 284 of the upper insulator 278 is tapered or oriented at an inward angle 318 with respect to a vertical plane 320 to match or complement the draft angle of the center housing 186 (FIG. 9). The outer surface 284 of the upper insulator 278 is angled inward in the direction from the lower end 292 of the upper insulator 278 to the upper end 294 of the upper insulator 278. Conversely, as best shown in FIG. 27, the outer surface 298 of the lower insulator 280 is oriented at an outward angle 322 with respect to the vertical plane 320 to match or complement the draft angle of the cold plate base 166 (FIG. 9). The outer surface 298 of the lower insulator 280 is angled outward in the direction from the lower end 306 of the lower insulator 280 to the upper end 308 of the lower insulator 280. In this regard, the outer surfaces 284, 298 of the upper and lower insulators 278 and 280 are oriented at the same or similar angles as the first and second portions 142a and 142b of the outer surface 142 of each of the first and second insulators 142 and 144. Therefore, like the first and second insulators 142 and 144, the insulator assembly 276 may cause the center housing 186 and the cold plate base 166 to be joined to the battery cell subassembly 102 via a tapered fit.

[0090] Like the ribs 146 on first and second insulators 132 and 134, the ribs 286 on the outer surface 284 of the upper insulator 278 are compressed by the center housing 186 as the center housing 186 is inserted over the battery cell subassembly 102. Thus, there is no gap between the outer surface 284 of the upper insulator 278 and the inner surface 200 (FIG. 9) of the center housing 186 where the ribs 286 contact the inner surface 200, which strengthens the tapered fit. Moreover, the amount by which the ribs 286 project from the outer surface 284 of the upper insulator 278 is greater than the size of the gap between the outer surface 284 of the upper insulator 278 and the inner surface 200 of the center housing 186. Thus, the contact between the ribs 286 on the upper insulator 278 and the inner surface 200 of the center housing 186 yields an interference fit between the center housing 186 and the battery cell subassembly 102. [0091] Similarly, the ribs 302 on the outer surface 298 of the lower insulator 280 are compressed by the cold plate base 166 as the cold plate base 166 is inserted over the battery cell subassembly 102. Thus, there is no gap between the outer surface 298 of the lower insulator 280 and the inner surface 198 (FIG. 9) of the cold plate base 166 where the ribs 302 contact the inner surface 198, which strengthens the tapered fit. Moreover, the amount by which the ribs 302 project from the outer surface 298 of the lower insulator 280 is greater than the size of the gap between the outer surface 298 of the lower insulator 280 and the inner surface 198 of the cold plate base 166. Thus, the contact between the ribs 302 on the lower insulator 280 and the inner surface 198 of the cold plate base 166 yields an interference fit between the cold plate base 166 and the battery cell subassembly 102.

[0092] In contrast to the inner surface 144 of the each of the first and second insulators 142 and 144, the inner surfaces 282 and 296 of the upper and lower insulators 278 and 280 are also oriented at an angle with respect to the vertical plane 320. Like the outer surface 284 of the upper insulator 278, the inner surface 282 of the upper insulator 278 is tapered or oriented at the inward angle 318 with respect to the vertical plane 320. Similarly, like the outer surface 298 of the lower insulator 280, the inner surface 296 of the lower insulator 280 is tapered or oriented at the outward angle 322 with respect to the vertical plane 320. Thus, the inner and outer surfaces 282 and 284 of the upper insulator 278 are parallel to one another, and the inner and outer surfaces 296 and 298 of the lower insulator 280 are parallel to one another. In various implementations, the inner and outer surfaces 282 and 284 of the upper insulator 278 may be tapered inward at different angles, and the inner and outer surfaces 296 and 298 of the lower insulator 280 may be tapered outward at different angles. [0093] Also, in contrast to the first and second insulators 142 and 144, the upper and lower insulators 278 and 280 include the ribs 286, 300 projecting from the inner surfaces 282 and 296 thereof. The amount by which the ribs 286 project from the inner surface 282 of the upper insulator 278 is greater than the size of the gap between the inner surface 282 of the upper insulator 278 and the outer side surfaces of the first and second cell stacks 128 and 130 (FIG. 10). Similarly, the amount by which the ribs 300 project from the inner surface 296 of the lower insulator 280 is greater than the size of the gap between the inner surface 296 of the lower insulator 280 and the outer side surfaces of the first and second cell stacks 128 and 130. Thus, the ribs 286, 300 on the upper and lower insulators 278 and 280 are compressed by the outer side surfaces of the first and second cell stacks 128 and 130 as the first and second cell stacks 128 and 130 are placed within the upper and lower insulators 278 and 280. The compression of the ribs 286, 300 yields an interference fit between the upper and lower insulators 278 and 280 and each of the first and second cell stacks 128 and 130, which holds the first and second cell stacks 128 and 130 within the upper and lower insulators 278 and 280.

[0094] If the upper and lower insulators 278 and 280 were formed as a single piece, the upper and lower insulators 278 and 280 would not be able to move relative to one another to absorb the tolerance stack up of the cell stacks 128, 130. Therefore, other design features may be necessary to absorb the tolerance stack up of the cell stacks 128, 130. In addition, if the upper and lower insulators 278 and 280 were formed as a single piece, the ribs 286, 300 on the inner surfaces 282, 296 may need to be oriented horizontally, rather than vertically as shown, to enable injection molding of the upper and lower insulators 278 and 280. To this end, if the upper and lower insulators 278 and 280 were formed as a single piece, the direction of a die draw used to form the upper and lower insulators 278 and 280 may be set by the orientation of the top and bottom ledges 290 and 304. Thus, since the top and bottom ledges 290 and 304 are oriented horizontally, it may be necessary to orient the ribs 286, 300 on the inner surfaces 282, 296 horizontally to be parallel to the direction of the die draw used to form the upper and lower insulators 278 and 280 as a single piece.

[0095] Since the upper and lower insulators 278 and 280 are separate pieces, the ribs 286, 300 on the inner surfaces 282, 296 may be oriented vertically as shown. In addition, the ribs 286, 300 on the inner surfaces 282, 296 may be spaced apart so that at least one of the ribs 286 and at least one of the ribs 300 is aligned with one of the battery cells 138 (FIG. 10). This ensures that each of the battery cells 138 is held firmly within the upper and lower insulators 278 and 280.

[0096] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0097] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." Unless explicitly described as being "direct," when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean "at least one of A, at least one of B, and at least one of C." [0098] In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.

[0099] In this application, including the definitions below, the term "module" or the term "controller" may be replaced with the term "circuit." The term "module" may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip. [0100] The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.

[0101] The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.

[0102] The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

[0103] The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer. [0104] The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0105] The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.

[0106] None of the elements recited in the claims are intended to be a means-plus- function element within the meaning of 35 U.S.C. §1 12(f) unless an element is expressly recited using the phrase "means for," or in the case of a method claim using the phrases "operation for" or "step for."

Claims

WHAT IS CLAIMED IS

1 . A battery pack comprising:

an outer housing including a bottom wall and a first sidewall, the first sidewall having a lower end and an upper end that is oriented at one of an inward angle and an outward angle relative to the lower end;

a battery cell subassembly including at least one cell stack and at least one insulator, the at least one cell stack having an outer side surface and including a plurality of battery cells, the at least one insulator being configured to fit around the outer side surface of the at least one cell stack to electrically insulate the outer side surface, the at least one insulator having an inner surface and an outer surface, the inner surface of the at least one insulator being configured to face the outer side surface of the at least one cell stack, the outer surface of the at least one insulator being configured to face an inner surface of the first sidewall of the outer housing, at least a portion of the outer surface of the at least one insulator being tapered to match the one of the inward angle and the outward angle of the first sidewall of the outer housing; and

a cover configured to fit over the outer housing, the outer housing and the cover cooperating with one another to enclose the battery cell subassembly.

2. The battery pack of claim 1 wherein:

the outer housing includes a center housing and a base, the center housing including the first sidewall, the base including the bottom wall and a second sidewall extending from the bottom wall and configured to be joined to the lower end of the first sidewall; and

the outer surface of at least one insulator includes a first portion and a second portion, the first portion of the outer surface being configured to face the inner surface of the first sidewall and being tapered to match the one of the inward angle and the outward angle of the first sidewall, the second portion of the outer surface being configured to face an inner surface of the second sidewall.

3. The battery pack of claim 2 wherein:

the upper end of the first sidewall of the center housing is oriented at the inward angle relative to the lower end of the first sidewall; and

the first portion of the outer surface of the at least one insulator is tapered to match the inward angle of the first sidewall.

4. The battery pack of claim 3 wherein:

the second sidewall has a lower end and an upper end that is oriented at the outward angle relative to the lower end of the second sidewall; and

the second portion of the outer surface of the at least one insulator is tapered to match the outward angle of the second sidewall.

5. The battery pack of claim 4 wherein:

the at least one insulator includes a one-piece insulator; and

the first and second portions of the outer surface of the at least one insulator are both disposed on the one-piece insulator.

6. The battery pack of claim 4 wherein:

the at least one insulator includes an upper insulator and a lower insulator;

the first portion of the outer surface of the at least one insulator is disposed on the upper insulator; and

the second portion of the outer surface of the at least one insulator is disposed on the lower insulator.

7. The battery pack of claim 6 wherein:

the lower insulator includes a bottom ledge projecting from the inner surface thereof, the bottom ledge being configured to support the at least one cell stack; and the upper insulator includes a top ledge projecting from the inner surface thereof, the top ledge being configured to cooperate with the bottom ledge to capture the at least one cell stack.

8. The battery pack of claim 2 further comprising a cooling subassembly that includes an inlet port, an outlet port, the base, a liquid flow path, and a cover, the liquid flow path configured to allow liquid to absorb heat from the battery cell subassembly as the liquid flows through the liquid flow path from the inlet port to the outlet port, a bottom surface of the base sealing a top of the liquid flow path, a top surface of the cover sealing a bottom of the liquid flow path.

9. The battery pack of claim 1 wherein, when the battery cell subassembly is disposed within the outer housing, the outer surface of the at least one insulator and the inner surface of the outer housing are separated by a uniform gap.

10. The battery pack of claim 1 wherein:

the at least one insulator includes a plurality of ribs disposed on the outer surface thereof; and

the plurality of ribs are configured to contact the inner surface the outer housing to secure the at least one insulator and the at least one cell stack within the outer housing.

1 1 . The battery pack of claim 1 wherein the at least one insulator includes a bottom ledge and a top ledge projecting from the inner surface of the at least one insulator, the bottom ledge being configured to support the at least one cell stack, the top ledge being configured to cooperate with the bottom ledge to capture the at least one cell stack.

12. The battery pack of claim 1 wherein:

the at least one cell stack includes a first cell stack and a second cell stack; and the at least one insulator includes first, second, and third insulators, the first insulator being configured to fit around the outer side surface of the first cell stack, the second insulator being configured to fit around the outer side surface of the second cell stack, the third insulator being configured to fit between the first and second cell stacks.

13. The battery pack of claim 1 further comprising a first circuit, a second circuit, and a main terminal, the first circuit being configured to electrically connect the plurality of battery cells to one another, the second circuit being configured to electrically connect the first circuit to the main terminal, the second circuit being disposed within the cover.

14. A battery pack comprising:

an outer housing including a bottom wall and a first sidewall, the first sidewall having a lower end and an upper end;

a battery cell subassembly including at least one cell stack and at least one insulator, the at least one cell stack having an outer side surface and including a plurality of battery cells, the at least one insulator being configured to fit around the outer side surface of the at least one cell stack to electrically insulate the outer side surface, the at least one insulator having an inner surface and an outer surface, the inner surface of the at least one insulator being configured to face the outer side surface of the at least one cell stack, the outer surface of the at least one insulator being configured to face an inner surface of the first sidewall of the outer housing, the at least one insulator including a first plurality of ribs disposed on the outer surface thereof, the first plurality of ribs being configured to contact the inner surface of the first sidewall of the outer housing to secure the at least one insulator and the at least one cell stack within the outer housing; and

15. The battery pack of claim 14 wherein the at least one insulator and the at least one cell stack are secured within the outer housing solely by the contact between the first plurality of ribs and the inner surface of the first sidewall of the outer housing.

16. The battery pack of claim 14 wherein:

when the battery cell subassembly is disposed within the outer housing, the outer surface of the at least one insulator and the inner surface of the outer housing are separated by a gap other than at locations where the first plurality of ribs contact the inner surface of the first sidewall of the outer housing; and

when the first plurality of ribs are in an uncompressed state, the first plurality of ribs project from the outer surface of the at least one insulator by an amount that is greater than a size of the gap between the outer surface of the at least one insulator and the inner surface of the outer housing.

17. The battery pack of claim 14 wherein:

the upper end of the first sidewall of the outer housing is angled inward relative to the lower end of the first sidewall; and

at least a portion of the outer surface of the at least one insulator is tapered to match the inward angle of the first sidewall.

18. The battery pack of claim 17 wherein:

the outer surface of at least one insulator includes a first portion and a second portion, the first portion of the outer surface being configured to face the inner surface of the first sidewall and being tapered to match the inward angle of the first sidewall, the second portion of the outer surface being configured to face the inner surface of the second sidewall, the first plurality of ribs being disposed on the first portion of the outer surface.

19. The battery pack of claim 18 wherein:

the second sidewall has a lower end and an upper end that is angled outward relative to the lower end of the second sidewall; and

20. The battery pack of claim 14 wherein the at least one insulator includes a second plurality of ribs disposed on the inner surface of the at least one insulator and configured to contact the outer side surface of the at least one cell stack to secure the at least one cell stack within the at least one insulator.

21 . A battery pack comprising:

an outer housing including a center housing and a base, the center housing including a first plurality of sidewalls having a lower end and an upper end that is angled inward relative to the lower end thereof, the base including a bottom wall and a second plurality of sidewalls having a lower end and an upper end that is angled outward relative to the lower end thereof, the second plurality of sidewalls extending from the bottom wall and being configured to be joined a lower end of the center housing;

a battery cell subassembly including a first cell stack including a first plurality of battery cells, a second cell stack including a second plurality of battery cells, a first insulator configured to fit around the first cell stack, and a second insulator configured to fit around the second cell stack, each of the first and second insulators having an outer surface with a first portion that is tapered to match the inward angle of the first plurality of sidewalls of the center housing and a second portion that is tapered to match the outward angle of the second plurality of sidewalls of the base, each of the first and second insulators including a first plurality of ribs disposed on the first portion of the outer surface thereof, the first plurality of ribs on the first and second insulators being configured to contact an inner surface of the center housing to secure the first and second insulators and the first and second cell stacks within the outer housing; and a cover configured to fit over the outer housing, the outer housing and the cover cooperating with one another to enclose the battery cell subassembly.

22. The battery pack of claim 21 wherein, when the battery cell subassembly is disposed within the outer housing, the outer surface of each of the first and second insulators and the inner surface of the outer housing are separated by a uniform gap other than at locations where the first plurality of ribs contact the inner surface of the outer housing.

23. The battery pack of claim 21 wherein each of the first and second insulators includes a second plurality of ribs disposed on an inner surface thereof, the second plurality of ribs on the inner surface of the first insulator being configured to contact an outer side surface of the first cell stack to secure the first cell stack within the first insulator, the second plurality of ribs on the inner surface of the second insulator being configured to contact an outer side surface of the second cell stack to secure the second cell stack within the second insulator.

24. The battery pack of claim 23 wherein each of the first and second insulators has an inner surface with a first portion that is tapered to match the taper of the first portion of the outer surface thereof and a second portion that is tapered to match the taper of the second portion of the outer surface thereof.

25. The battery pack of claim 23 wherein:

each of the first and second insulators includes an upper insulator piece and a lower insulator piece that is separate from the upper insulator piece;

the upper insulator pieces have outer surfaces that forms the first portions of the outer surfaces of the first and second insulators;

the lower insulator pieces have outer surfaces that forms the second portions of the outer surfaces of the first and second insulators;

the first plurality of ribs extend vertically on the outer surfaces of the upper and lower insulator pieces; and

the second plurality of ribs extend vertically on inner surfaces of the upper and lower insulator pieces.