Battery pack

Abstract

To provide a battery pack in which a bus bar module can be precisely positioned also in a Cell-to-Pack structure.SOLUTION: A battery pack includes: a stack including a plurality of battery cells arranged side by side in a first direction; a case that has a side wall facing the stack in the first direction and that accommodates the stack; and a bus bar module disposed on the stack, the bus bar module including a bus bar that electrically connects the plurality of battery cells and a plate member that accommodates the bus bar. Therein the plate member has a first positioning mechanism that positions the bus bar module in the first direction by biasing the side wall of the case.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Japanese Patent Laying-Open No. 2013-191422 (Patent Document 1) discloses that 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-191422 A Summary of the Invention [Problem to be solved by the invention]

[0004] Battery packs are beginning to adopt a cell-to-pack structure in which a stack including multiple battery cells is directly housed in a case without using end plates and bind bars (module structure) that restrain the multiple battery cells. In the modular structure, for example, a bind bar can be used as a fixing part for positioning when positioning a bus bar module relative to the stack of multiple battery cells, but in the cell-to-pack structure, since there is no bind bar, a mechanism different from that of a modular battery pack is required.

[0005] The objective of this technology is to provide a battery pack that enables accurate positioning of the 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 battery pack comprising: a stack including a plurality of battery cells arranged in a first direction; a case having a sidewall facing the stack from the first direction and housing the stack; and a busbar module arranged on the stack and including a busbar electrically connecting the plurality of battery cells and a plate member housing the busbar, the plate member having a first positioning mechanism that positions the busbar module in the first direction by biasing the sidewall of the case.

[0008] [2] A battery pack as described in [1], wherein the multiple battery cells each have an upper surface that faces the plate member, the plate member has a bottom surface that faces the top surfaces of the multiple battery cells, and a protruding rib that protrudes from the bottom surface of the plate member toward the top surfaces of the multiple battery cells is provided on a part of the bottom surface of the plate member, and the protruding rib abuts the top surfaces of the multiple battery cells.

[0009] [3] A battery pack as described in [2], wherein the plurality of battery cells each have a housing including a top surface and a discharge valve provided on the top surface that opens when the internal pressure of the housing rises, and the first positioning mechanism is positioned so as not to interfere with the discharge valve when the first positioning mechanism is pressed against the side wall of the case.

[0010] [4] A battery pack according to any one of [1] to [3], wherein the laminate includes a separator disposed between a plurality of battery cells, the separator having a protruding portion that protrudes toward the plate member side beyond the plurality of battery cells, and the plate member has a recessed portion that avoids the protruding portion of the separator.

[0011] [5] The battery pack of any one of [1] to [4], wherein the stack includes a first stack and a second stack adjacent to the first stack in a second direction perpendicular to the first direction, the first stack and the second stack each including a plurality of battery cells and each facing the side wall from the first direction, the busbar module includes a first busbar module and a second busbar module arranged on the first stack and the second stack, respectively, the first busbar module and the second busbar module each including a busbar and a plate member, at least one of the first busbar module and the second busbar module is inserted between the first stack and the second stack, and has a second positioning mechanism that positions the first busbar module or the second busbar module in the second direction. Effect of the Invention

[0012] According to the present technology, a first positioning mechanism is provided that positions the busbar module in the stacking direction (first direction) of the battery cells by pressing the side wall of the case, so that the busbar module can be positioned with high accuracy even in a battery pack with a cell-to-pack structure in which a stack including multiple battery cells is directly housed in a case. [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] 6 is a diagram (part 1) showing a modified example of the positioning mechanism shown in FIG. 5. [Figure 10] 6 is a diagram (part 2) showing a modified example of the positioning mechanism shown in FIG. 5. FIG. 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] 9 and 10 are diagrams illustrating modified examples of the positioning mechanism for the bus bar module 30 in the Y-axis direction.

[0049] The positioning mechanism 317A shown in FIG. 9 includes an adjuster 317A1 that is inserted into a hole provided in an end surface 311 of the plate member 310 and protrudes from the end surface 311 toward the side wall 21 of the case 20. The positioning mechanism 317B shown in FIG. 10 includes an elastically deformable expandable part 317B1 that protrudes from the end surface 311 of the plate member 310 toward the side wall 21 of the case 20. When the plate member 310 approaches the side wall 21 of the case 20, both of the positioning mechanisms 317A and 317B shown in FIG. 9 and FIG. 10 generate a repulsive force that presses the side wall 21 of the case 20, and can urge the plate member 310 toward a predetermined position. As a result, the busbar module 30 is positioned in the Y-axis direction.

[0050] As described above, the battery pack 1 according to this embodiment employs a cell-to-pack structure in which the laminate 10 including multiple battery cells 100 is stored directly in the case 20, and therefore components such as the bind bar in the module structure cannot be used as components for positioning the bus bar module 30.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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]

[0059] 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, 124 second side, 125 third side, 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, 317A, 317B positioning mechanism, 317A1 Adjuster, 317B1 telescopic portion, 318 recess, 319 protruding rib, 319A bottom surface, 320 bus bar, 321 root portion, 322, 323 connection portion, 330, 330A, 330B positioning mechanism, 331A, 331B insertion portion, 410 wiring, 420 screw.

Claims

1. A stack including a plurality of battery cells aligned in a first direction; a case having a side wall facing the stack from the first direction and configured to house the stack; a bus bar module that is disposed on the stack and that electrically connects the plurality of battery cells, and that includes a bus bar module that includes a plate member that houses the bus bar; The plate member has a first positioning mechanism that positions the bus bar module in the first direction by biasing the side wall of the case.

2. Each of the plurality of battery cells has an upper surface facing the plate member, the plate member has a bottom surface that faces the top surfaces of the plurality of battery cells; 2. The battery pack according to claim 1, wherein a protruding rib is provided on a portion of the bottom surface of the plate member, protruding from the bottom surface of the plate member toward the top surfaces of the plurality of battery cells, the protruding rib abutting the top surfaces of the plurality of battery cells.

3. each of the plurality of battery cells has a housing including the upper surface and a discharge valve provided on the upper surface and configured to open when an internal pressure of the housing increases; The battery pack according to claim 2 , wherein the first positioning mechanism is located at a position not interfering with the exhaust valve when the first positioning mechanism presses against the side wall of the case.

4. the stack includes a separator provided between the plurality of battery cells; the separator has a protruding portion that protrudes toward the plate member side beyond the plurality of battery cells, The battery pack according to claim 1 or 2, wherein the plate member has a recess that avoids the protrusion of the separator.

5. the stack includes a first stack and a second stack adjacent to the first stack in a second direction perpendicular to the first direction, the first stack and the second stack each include the plurality of battery cells and each face the side wall from the first direction; the bus bar module includes a first bus bar module and a second bus bar module disposed on the first stack and the second stack, respectively; the first bus bar module and the second bus bar module each include the bus bar and the plate member; 3. The battery pack according to claim 1, wherein at least one of the first busbar module and the second busbar module has a second positioning mechanism that is inserted between the first stack and the second stack and that positions the first busbar module or the second busbar module in the second direction.

Images