Battery pack

Abstract

To provide a battery pack that prevents incorrect assembly of a bus bar module even in a cell-to-pack structure.SOLUTION: At least one of the first bus bar module and the second bus bar module protrudes toward the other of the first bus bar module and the second bus bar module. Incorrect assembly of the first bus bar module or the second bus bar module are prohibited by interference. The battery pack has a protrusion part that does not cause interference when the first bus bar module and the second bus bar module are correctly assembled.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present technology relates to battery packs. [Background technology]

[0002] China Utility Model No. 217468616 (Patent Document 1) discloses a cell-to-pack structure in which a stack containing multiple battery cells is stored directly in a case, without using end plates and bind bars (module structure) to restrain multiple battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] China Utility Model No. 217468616 Summary of the Invention [Problem to be solved by the invention]

[0004] In a cell-to-pack structure, when a busbar module, in which multiple busbars are modularized by housing them in a plate member, is mounted on top of a stack of multiple battery cells, the busbar module is installed after the stack of battery cells is housed in a case, which can lead to incorrect assembly in terms of the type or installation direction of the busbar module.

[0005] The objective of this technology is to provide a battery pack that can prevent incorrect assembly of a bus bar module even in a cell-to-pack structure. [Means for solving the problem]

[0006] The present technology provides the following battery pack.

[0007] [1] A method for manufacturing an electric vehicle comprising: a first stack including a plurality of first battery cells arranged in a first direction; a second stack including a plurality of second battery cells arranged in the first direction and adjacent to the first stack in a second direction perpendicular to the first direction; a case having side walls supporting the first stack and the second stack from the first direction and housing the first stack and including a first bus bar module arranged on the first stack and a first plate member housing the first bus bar; and a first bus bar module electrically connecting the plurality of first battery cells to each other and a first plate member housing the first bus bar. and a second busbar module including a second busbar disposed on the second laminate, the second busbar module including a second plate member that houses the second busbar, wherein at least one of the first busbar module and the second busbar module has a protrusion that protrudes toward the other of the first busbar module and the second busbar module and interferes with and prevents incorrect assembly of the first busbar module or the second busbar module but does not cause interference when the first busbar module and the second busbar module are correctly assembled.

[0008] [2] The battery pack described in [1], wherein the protrusion includes a positioning mechanism that is inserted between the first stack and the second stack and positions the first busbar module or the second busbar module in the second direction.

[0009] [3] The battery pack described in [2], wherein the positioning mechanism is press-fitted between the first stack and the second stack.

[0010] [4] The battery pack described in [2] or [3], wherein the protrusion includes a first protrusion that constitutes the positioning mechanism and a second protrusion that is formed separately from the first protrusion.

[0011] [5] The battery pack described in any one of [1] to [4], wherein the case has a side wall supporting the first laminate and the second laminate from the first direction, and the first plate member and the second plate member each have a second positioning mechanism that positions the first busbar module and the second busbar module, respectively, in the first direction by biasing the side wall of the case. Effect of the Invention

[0012] According to this technology, a protrusion is provided on the busbar module that interferes with incorrect assembly and does not cause interference when assembled correctly, thereby making it possible to prevent incorrect assembly of the busbar module even in battery packs with a cell-to-pack structure. [Brief description of the drawings]

[0013] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a top view of a plate member in the bus bar module. [Figure 4] FIG. 2 is a perspective view showing a structure around a bus bar. [Diagram 5] 13A and 13B are diagrams illustrating a positioning mechanism for the bus bar module in the Y-axis direction. [Figure 6] FIG. 2 is a perspective view showing the structure between the bus bar module and the upper surface of the battery cell. [Figure 7] FIG. 4 is a perspective view showing a rear surface of a plate member in the bus bar module. [Figure 8] 13A and 13B are diagrams illustrating a positioning mechanism for the bus bar module in the X-axis direction. [Figure 9] 11A and 11B are diagrams for explaining a mechanism for preventing erroneous assembly of the bus bar module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof will not be repeated.

[0015] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0016] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0017] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0018] In this specification, the term "battery" is not limited to lithium ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium ion batteries. In this specification, the term "battery pack" can be mounted in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and the like. However, the use of the "battery cell" is not limited to in-vehicle use.

[0019] Fig. 1 is an exploded perspective view of a battery pack 1. As shown in Fig. 1, the battery pack 1 includes a stack 10 including a plurality of battery cells 100 (see Fig. 2) arranged in a Y-axis direction (first direction), a case 20 that houses the stack 10, and a bus bar module 30 arranged on the stack 10.

[0020] The laminate 10 includes a laminate 10A (first laminate), a laminate 10B (second laminate), and a laminate 10C (third laminate). The laminates 10A and 10B are adjacent to each other in the X-axis direction (second direction). The laminates 10B and 10C are adjacent to each other in the X-axis direction.

[0021] The case 20 has a side wall 21 that faces the stacks 10A, 10B, 10C in the Y-axis direction. The side wall 21 directly supports the stacks 10A, 10B, 10C from both sides in the Y-axis direction. In this manner, the battery pack 1 according to this embodiment employs a cell-to-pack structure in which the stack 10 including the multiple battery cells 100 is stored directly in the case.

[0022] The busbar module 30 includes a busbar module 30A (first busbar module) arranged on the laminate 10A, a busbar module 30B (second busbar module) arranged on the laminate 10B, and a busbar module 30C (third busbar module) arranged on the laminate 10C.

[0023] Fig. 2 is a perspective view showing the configuration of the battery cell 100 constituting the laminates 10A, 10B, and 10C. As shown in Fig. 2, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110, a housing 120, and a gas release valve 130.

[0024] The electrode terminals 110 are formed on the housing 120. The electrode terminals 110 include a positive terminal 111 and a negative terminal 112 as two electrode terminals 110 arranged along an X-axis direction (second direction) perpendicular to a Y-axis direction (first direction). The positive terminal 111 and the negative terminal 112 are provided apart from each other in the X-axis direction.

[0025] The housing 120 has a substantially rectangular parallelepiped shape. An electrode body and an electrolyte (not shown) are accommodated in the housing 120. The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and a third side surface 125.

[0026] The upper surface 121 is a plane perpendicular to the Z-axis direction. The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction (third direction) perpendicular to the Y-axis direction (first direction) and the X-axis direction (second direction).

[0027] Each of the first side surface 123 and the second side surface 124 is formed of a plane perpendicular to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape with the X-axis direction being the long side direction and the Z-axis direction being the short side direction when viewed in the Y-axis direction.

[0028] The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the battery cells 100 adjacent to each other in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

[0029] Gas exhaust valve 130 is provided on upper surface 121. When the internal pressure of housing 120 increases to a predetermined value or higher due to gas generated inside housing 120, gas exhaust valve 130 opens and exhausts the gas to the outside of housing 120.

[0030] Next, the basic configuration of the busbar module 30 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a top view of a plate member 310 included in the busbar module 30. Fig. 4 is a perspective view showing the structure around a busbar 320 in the busbar module 30.

[0031] Each of the busbar modules 30A, 30B, and 30C includes a plate member 310 shown in Fig. 3. As shown in Fig. 3, the plate member 310 includes an end face 311 located at the end in the Y-axis direction, an end face 312 located at the end in the X-axis direction, a through-hole 313 formed in a position corresponding to the gas release valve 130 of the battery cell 100, and a wall portion 314 that divides the space on the plate member 310 into multiple sections.

[0032] As shown in Fig. 4, a bus bar 320 is stored in each space partitioned by the wall portion 314. The bus bar 320 is made of a conductor (typically, a metal member). The bus bar 320 electrically connects the electrode terminals 110 of the multiple battery cells 100 to each other. The bus bar 320 includes a root portion 321 extending in the Y-axis direction, and a connection portion 322 (first connection portion) and a connection portion 323 (second connection portion) protruding from the root portion 321 in the X-axis direction. The connection portions 322 and 323 are each connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0033] The wall portion 314 of the plate member 310 includes a first portion 314A, a second portion 314B, and a third portion 314C. The first portion 314A and the second portion 314B are formed to extend in the X-axis direction. The first portion 314A and the second portion 314B are spaced apart from each other in the Y-axis direction. The third portion 314C connects the first portion 314A and the second portion 314B.

[0034] Ribs 315 and locks 316 are formed on wall portion 314. Ribs 315 protrude on both sides in the Y-axis direction from positions adjacent to third portion 314C of wall portion 314. Ribs 315 position adjacent bus bars 320 in the Y-axis direction. Locks 316 lock bus bars 320 in the Z-axis direction. The shapes and arrangements of ribs 315 and locks 316 are not limited to those shown in FIG. 4 and can be changed as appropriate.

[0035] Bus bar 320 is connected to wiring 410. Wiring 410 is fixed to bus bar 320 by screws 420. The form of wiring 410 and screws 420 is not limited to that shown in Fig. 4, and the wiring may be formed by, for example, a flexible wiring board.

[0036] The electrode terminals 110 and the busbars 320 of the battery cells 100 are welded together after being positioned relative to each other in the X-axis and Y-axis directions. By performing this positioning accurately, the welding process between the electrode terminals 110 and the busbars 320 can be performed with high efficiency and quality. When the busbars 320 are stored in the space partitioned by the wall portions 314, they are accurately positioned relative to the plate member 310 in the X-axis and Y-axis directions. Therefore, it is necessary to accurately position the plate member 310 and the stack 10.

[0037] A positioning mechanism for the bus bar module 30 (plate member 310) in this embodiment will be described with reference to FIGS.

[0038] Fig. 5 is a diagram showing a positioning mechanism for the busbar module 30 in the Y-axis direction. As shown in Fig. 5, the plate member 310 of the busbar module 30 has a positioning mechanism 317 that biases the side wall 21 of the case 20 to position the busbar module 30 in the Y-axis direction.

[0039] 5 is configured with a snap-fit-shaped protrusion formed on end surface 311 of plate member 310. The protrusion configuring positioning mechanism 317 protrudes from end surface 311 of plate member 310 toward side wall 21. When plate member 310 is installed in case 20, positioning mechanism 317 presses side wall 21 of case 20, urging plate member 310 toward a predetermined position. As a result, busbar module 30 is positioned in the Y-axis direction.

[0040] The positioning mechanisms 317 may be provided on end faces 311 of the plate member 310 on both sides in the Y-axis direction, or on only one side in the Y-axis direction of the plate member 310. When the positioning mechanisms 317 are provided on both sides in the Y-axis direction, the plate member 310 is urged toward the center of the case 20 in the Y-axis direction, and is positioned at a position where the urging forces by the positioning mechanisms 317 on both sides are balanced. When the positioning mechanism 317 is provided on one side in the Y-axis direction, the plate member 310 is urged toward the side wall 21 opposite to the side on which the positioning mechanism 317 is provided, and is positioned using the side wall 21 as a reference plane.

[0041] The protrusions constituting the positioning mechanism 317 deform toward the center of the stack 10 as a reaction to the pressure applied to the side wall 21 of the case 20. At this time, it is preferable that the positioning mechanism 317 is located in a position that does not interfere with the gas release valve 130 when viewed from the Z axis direction. In this way, the busbar module 30 can be positioned in the Y axis direction without affecting the release of gas from the gas release valve 130 of the battery cell 100 located at the end in the Y axis direction.

[0042] FIG. 6 is a perspective view showing the structure between the bus bar module 30 and the upper surface 121 of the battery cell 100.

[0043] As shown in FIG. 6, the laminate 10 includes a separator 11 provided between the multiple battery cells 100. The separator 11 may be a film or tape that covers the first side surface 123, the second side surface 124, and the third side surface 125 of the battery cell 100. The separator 11 may be a film that wraps around the housing 120. The separator 11 may be a plate-like member (plate) that is sandwiched between the adjacent battery cells 100. The separator 11 may also be formed by combining the above film or tape with a plate-like member. The separator 11 has a protruding portion 11A that protrudes toward the plate member 310 side beyond the multiple battery cells 100. The plate member 310 has a recessed portion 318 that avoids the protruding portion 11A of the separator 11.

[0044] Fig. 7 is a perspective view showing the back surface of the plate member 310. As shown in Fig. 7, the plate member 310 has a bottom surface 319A. The bottom surface 319A faces the upper surface of the battery cell 100. A protruding rib 319 that protrudes from the bottom surface 319A of the plate member 310 toward the upper surface 121 of the battery cell 100 is provided on a part of the bottom surface 319A of the plate member 310. The protruding rib 319 abuts against the upper surface 121 of the battery cell 100. In the example of Fig. 7, the protruding rib 319 is formed discontinuously on both sides of the through hole 313 so as to extend in the Y-axis direction.

[0045] Fig. 8 is a diagram showing a positioning mechanism for the busbar module 30 in the X-axis direction. As shown in Fig. 8, the busbar module 30 has a positioning mechanism 330 that is inserted between two adjacent laminates (laminates 10A and 10B in the example of Fig. 8) and positions the busbar module 30 in the X-axis direction. In the example of Fig. 8, the laminate 10A has the positioning mechanism 330A, and the laminate 10B has the positioning mechanism 330B, but the scope of the present technology is not limited to a case where all laminates 10 have the positioning mechanism 330, and only a part of the multiple laminates 10 may have the positioning mechanism 330.

[0046] The positioning mechanism 330A has an insertion portion 331A that is press-fitted between the laminates 10A and 10B. When the insertion portion 331A is press-fitted between the laminates 10A and 10B, the busbar module 30A is biased in a direction away from the laminate 10B. At this time, the insertion portion 331A comes into contact with a side surface of the laminate 10A, thereby positioning the busbar module 30A in the X-axis direction.

[0047] The positioning mechanism 330B has an insertion portion 331B that is press-fitted between the laminates 10A, 10B. When the insertion portion 331B is press-fitted between the laminates 10A, 10B, the busbar module 30B is biased in a direction away from the laminate 10A. At this time, the insertion portion 331B comes into contact with a side surface of the laminate 10B, thereby positioning the busbar module 30B in the X-axis direction.

[0048] The battery pack 1 according to the present embodiment employs a cell-to-pack structure in which a laminate 10 including a plurality of battery cells 100 is housed directly in a case 20, and therefore differs from a modular structure in that the bus bar module 30 is installed after the laminate 10 is housed in the case 20. For this reason, a mechanism for preventing erroneous assembly of the bus bar module 30 that differs from that of a modular battery pack is required.

[0049] Fig. 9 is a diagram for explaining an erroneous assembly prevention mechanism of the busbar module 30. In the example shown in Fig. 9, positioning mechanisms 330A, 330B, 330C and protruding portions 340A, 340B, 340C are formed in the plate members 310A, 310B, 310C of the busbar modules 30A, 30B, 30C, respectively. The positioning mechanisms 330A, 330B, 330C (first protruding portions) and the protruding portions 340A, 340B, 340C (second protruding portions) are provided integrally with the plate members 310A, 310B, 310C, and are formed to protrude from an end surface 312 of each plate member 310 in the X-axis direction.

[0050] The protrusion 340A formed on the plate member 310A includes a protrusion 340A1 that protrudes toward the plate member 310B side and a protrusion 340A2 that protrudes on the opposite side to the plate member 310B. The protrusion 340B formed on the plate member 310B includes a protrusion 340B1 that protrudes toward the plate member 310C side and a protrusion 340B2 that protrudes toward the plate member 310A side. The protrusion 340C formed on the plate member 310C protrudes toward the plate member 310B side.

[0051] 9, when the busbar modules 30A, 30B, and 30C are correctly assembled, the positioning mechanisms 330A, 330B, and 330C and the protrusions 340A, 340B, and 340C do not interfere with each other. On the other hand, when an attempt is made to erroneously assemble the busbar modules 30A, 30B, and 30C, the positioning mechanisms 330A, 330B, and 330C and the protrusions 340A, 340B, and 340C interfere with each other. This makes it possible to prevent erroneous assembly of the busbar module 30.

[0052] Specifically, the busbar module 30C is provided with a general terminal portion 350, and the busbar module 30C can only be assembled in the correct position and direction. In addition, the general terminal portion 350 and its mounting portion serve as markers, preventing the wrong types of busbar modules, such as the busbar modules 30A and 30B, from being assembled in a location where the busbar module 30C is to be installed.

[0053] After busbar module 30C is correctly assembled, if one attempts to install busbar module 30B by assembling plate member 310B in the incorrect installation direction (in a direction rotated 180 degrees), protrusion 340B2 of plate member 310B will interfere with protrusion 340C of plate member 310C.

[0054] Furthermore, when attempting to assemble bus bar module 30A to a location where bus bar module 30B is to be installed, protrusion 340A1 of plate member 310A interferes with protrusion 340C of plate member 310C. Furthermore, positioning mechanism 330A provided on plate member 310A interferes with positioning mechanism 330C provided on plate member 310C.

[0055] After correctly assembling busbar modules 30C and 30B, if one attempts to install busbar module 30A with the plate member 310A installed in the wrong direction (associating it with a direction rotated 180 degrees), protrusion 340B2 of plate member 310B will interfere with protrusion 340A2 of plate member 310A.

[0056] Furthermore, when attempting to assemble bus bar module 30B at the location where bus bar module 30A is to be installed, protrusions 340B2 of plate member 310B interfere with each other. Furthermore, positioning mechanisms 330B provided on plate member 310B also interfere with each other.

[0057] In this way, the busbar module 30 according to this embodiment is provided with a mechanism that prevents incorrect assembly by causing interference and prevents interference when assembled correctly, thereby making it possible to prevent incorrect assembly of the busbar module 30 even in a battery pack 1 having a cell-to-pack structure. In the busbar module 30 according to this embodiment, when multiple types of busbar modules with different shapes are arranged in one battery pack, there is only one assembly method that prevents the busbar modules of different shapes from interfering with each other.

[0058] However, the arrangement of the positioning mechanisms 330A, 330B, and 330C and the protrusions 340A, 340B, and 340C shown in FIG. 9 is merely an example, and the scope of the present technology is not limited thereto.

[0059] Furthermore, since the battery pack 1 employs a cell-to-pack structure, members such as bind bars in the module structure cannot be used as members for positioning the bus bar module 30.

[0060] In the battery pack 1 of this embodiment, the positioning mechanism 317 provided on the plate member 310 biases the side wall 21 of the case 20, thereby positioning the busbar module 30 in the Y-axis direction. Therefore, in the battery pack 1 having a cell-to-pack structure, the busbar module 30 can be positioned with high accuracy without providing a complex mechanism.

[0061] In the battery pack 1, a protruding rib 319 that protrudes from a bottom surface 319A of the plate member 310 toward the battery cell 100 abuts against an upper surface 121 of the battery cell 100. By abutting the protruding rib 319 against the battery cell 100 in this way, the contact area between the plate member 310 and the upper surface 121 of the battery cell 100 is reduced, and frictional resistance when the plate member 310 moves relative to the battery cell 100 is reduced, allowing the plate member 310 to be positioned smoothly and accurately.

[0062] The shape or arrangement of the protruding ribs 319 is not limited to that shown in Fig. 7. Furthermore, the protruding ribs 319 are not necessarily an essential component in the present technology.

[0063] In the battery pack 1, the plate member 310 has the recess 318 that avoids the protrusion 11A of the separator 11, so that when the positioning mechanism 317 positions the plate member 310 in the Y-axis direction, the movement of the plate member 310 in the Y-axis direction is not hindered by the protrusion 11A of the separator 11. Therefore, the positioning of the plate member 310 can be performed smoothly and accurately.

[0064] However, in the present technology, the protruding portion 11A of the separator 11 and the recessed portion 318 of the plate member 310 are not necessarily essential components.

[0065] The battery pack 1 is provided with a positioning mechanism 330 that is inserted between the laminates 10A and 10B and positions the busbar modules 30A and 30B in the X-axis direction. This allows the plate member 310 to be positioned in the X-axis direction as well as in the Y-axis direction.

[0066] However, in the present technology, the positioning mechanism 330 in the X-axis direction is not necessarily a required configuration. In addition, all of the multiple stacks 10A, 10B, and 10C may be provided with the positioning mechanism 330, or only some of the multiple stacks 10A, 10B, and 10C may be provided with the positioning mechanism 330.

[0067] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0068] 1 battery pack, 10, 10A, 10B, 10C laminate, 11 separator, 11A protrusion, 20 case, 21 side wall, 30, 30A, 30B, 30C busbar module, 100 battery cell, 110 electrode terminal, 110A protrusion, 111 positive electrode terminal, 112 negative electrode terminal, 120 housing, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 130 gas exhaust valve, 310 plate member, 311, 312 end surface, 313 through hole, 314 wall portion, 314A first portion, 314B second portion, 314C third portion, 315 rib, 316 lock, 317 positioning mechanism, 318 recess, 319 Protruding rib, 319A bottom surface, 320 bus bar, 321 root portion, 322, 323 connection portion, 330, 330A, 330B, 330C positioning mechanism, 331A, 331B insertion portion, 340A, 340A1, 340A2, 340B, 340B1, 340B2, 340C protruding portion, 350 total terminal portion, 410 wiring, 420 screw.

Claims

1. A first stack including a plurality of first battery cells aligned in a first direction; a second stack adjacent to the first stack in a second direction perpendicular to the first direction and including a plurality of second battery cells aligned in the first direction; a case having a side wall supporting the first stack and the second stack from the first direction and configured to house the first stack and the second stack; a first bus bar module disposed on the first stack, the first bus bar module including a first bus bar electrically connecting the first plurality of battery cells and a first plate member housing the first bus bar; a second bus bar module disposed on the second stack, the second bus bar module including a second bus bar electrically connecting the plurality of second battery cells and a second plate member housing the second bus bar; a battery pack, wherein at least one of the first busbar module and the second busbar module has a protrusion that protrudes toward the other of the first busbar module and the second busbar module, interferes with and prevents incorrect assembly of the first busbar module or the second busbar module, and does not cause interference when the first busbar module and the second busbar module are correctly assembled.

2. 2. The battery pack of claim 1, wherein the protrusion includes a positioning mechanism that is inserted between the first stack and the second stack and positions the first bus bar module or the second bus bar module in the second direction.

3. The battery pack according to claim 2 , wherein the positioning mechanism is press-fit between the first stack and the second stack.

4. 4. The battery pack according to claim 2, wherein the protrusion includes a first protrusion constituting the positioning mechanism, and a second protrusion formed separately from the first protrusion.

5. the case has a side wall supporting the first stack and the second stack from the first direction, 3. The battery pack of claim 1, wherein the first plate member and the second plate member each have a second positioning mechanism that positions the first bus bar module and the second bus bar module in the first direction by biasing the side wall of the case.

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