Battery pack

Abstract

The invention relates to a battery pack. A battery pack (1) is provided with: a laminated body (10) including a plurality of battery cells (100) arranged in a first direction; a case (20) that has a side wall (21) facing the laminated body (10) from the first direction, and that houses the laminated body (10); and a bus bar module (30) that is disposed on the laminated body (10) and that includes a bus bar (320) that electrically connects the plurality of battery cells (100) and a plate member (310) that houses the bus bar (320), the plate member (310) having a first positioning mechanism (317) that positions the bus bar module (30) in the first direction by urging a side wall (21) of the case (20).

Description

Technical Field

[0001] The invention relates to a battery pack. Background Art

[0002] Japanese Patent Application Laid-Open No. 2013-191422 discloses that a bus bar module formed by accommodating a plurality of bus bars in a plate member is mounted on a stack of a plurality of battery cells. Summary of the invention

[0003] In battery packs, a Cell-to-Pack structure is beginning to be adopted, in which a stack of multiple battery cells is directly housed in a housing without using end plates and restraint bars (module structure) for restraining multiple battery cells. When positioning a busbar module relative to a stack of multiple battery cells, restraint bars, for example, can be used as a fixing portion for positioning in a module structure, but in a Cell-to-Pack structure, since there are no restraint bars, a mechanism different from that of a module structured battery pack is required.

[0004] An object of the present invention is to provide a battery pack capable of positioning a bus bar module with high accuracy even in a Cell-to-Pack structure.

[0005] The present invention provides the following battery pack.

[0006] [1] A battery pack, wherein the battery pack comprises: a stack including a plurality of battery cells arranged in a first direction; a housing having a side wall facing the stack from the first direction and accommodating the stack; and a busbar module arranged on the stack, including a busbar electrically connecting the plurality of battery cells and a plate member accommodating the busbar, the plate member having a first positioning mechanism for positioning the busbar module in the first direction by applying force to the side wall of the housing.

[0007] [2] In the battery pack described in [1], the plurality of battery cells respectively have an upper surface facing the plate member, the plate member has a bottom surface facing the upper surfaces of the plurality of battery cells, and a protruding rib protruding from the bottom surface of the plate member toward the upper surfaces of the plurality of battery cells is provided on a portion of the bottom surface of the plate member, and the protruding rib abuts against the upper surfaces of the plurality of battery cells.

[0008] [3] In the battery pack described in [2], each of the plurality of battery cells includes a frame including an upper surface and a discharge valve disposed on the upper surface and opening when the internal pressure of the frame rises, and the first positioning mechanism is located at a position that does not interfere with the discharge valve when the side wall of the shell is pressed.

[0009] [4] In the battery pack described in any one of [1] to [3], the stack includes a spacer disposed between the plurality of battery cells, the spacer having a protrusion protruding toward the plate member from the plurality of battery cells, and the plate member having a recess avoiding the protrusion of the spacer.

[0010] [5] In the battery pack described in any one of [1] to [4], the stack includes a first stack and a second stack adjacent to the first stack in a second direction orthogonal to the first direction, the first stack and the second stack respectively include a plurality of battery cells and are respectively facing the side wall from the first direction, the busbar module includes a first busbar module and a second busbar module respectively arranged on the first stack and the second stack, the first busbar module and the second busbar module respectively include a busbar and a plate member, and at least one of the first busbar module and the second busbar module has a second positioning mechanism inserted between the first stack and the second stack and positioning the first busbar module or the second busbar module in the second direction.

[0011] The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is an exploded perspective view of the battery pack.

[0013] Figure 2 It is a three-dimensional diagram of a battery cell.

[0014] Figure 3 It is a top view of the plate component in the busbar module.

[0015] Figure 4 It is a perspective view showing the structure around the busbar.

[0016] Figure 5 It is a diagram showing a positioning mechanism of the busbar module in the Y-axis direction.

[0017] Figure 6 It is a perspective view showing the structure between the bus bar module and the upper surface of the battery cell.

[0018] Figure 7 It is a perspective view showing the back side of a plate member in a busbar module.

[0019] Figure 8 It is a diagram showing a positioning mechanism of the busbar module in the X-axis direction.

[0020] Fig. 9 Yes means Figure 5 FIG. 1 is a diagram showing a modified example of the positioning mechanism shown.

[0021] Fig.10 Yes means Figure 5 FIG. 2 is a diagram showing a modified example of the positioning mechanism shown. DETAILED DESCRIPTION

[0022] Hereinafter, an embodiment of the present invention will be described. In addition, the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

[0023] In addition, in the embodiments described below, when the number, quantity, etc. are mentioned, except for the cases specifically described, the scope of the present invention is not necessarily limited to the number, quantity, etc. In addition, in the following embodiments, each component is not necessarily essential to the present invention except for the cases specifically described. In addition, the present invention is not necessarily limited to achieving all the effects mentioned in the present embodiments.

[0024] In addition, in this specification, the descriptions of “comprise”, “include”, and “have” are open-ended. That is, when a certain structure is included, other structures other than the structure may be included or other structures other than the structure may not be included.

[0025] In addition, in this specification, when geometric terms and terms indicating position and direction relationships, such as "parallel", "orthogonal", "oblique 45°", "coaxial", "along", etc., are used, these terms allow for manufacturing errors or slight changes. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used to indicate relative positional relationships in one state, and the relative positional relationship can be flipped or rotated to any angle by the setting direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0026] In this specification, "battery" is not limited to lithium-ion batteries, and can include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "battery pack" can be installed in hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV) and electric vehicles (BEV). However, the use of "battery cells" is not limited to vehicle use.

[0027] Figure 1 1 is an exploded perspective view of the battery pack 1. Figure 1 As shown, the battery pack 1 includes: a plurality of battery cells 100 (see Figure 2) of a stacked body 10; a housing 20 for housing the stacked body 10; and a busbar module 30 disposed on the stacked body 10.

[0028] The stack 10 includes a stack 10A (first stack), a stack 10B (second stack), and a stack 10C (third stack). The stacks 10A and 10B are adjacent to each other in the X-axis direction (second direction). The stacks 10B and 10C are adjacent to each other in the X-axis direction.

[0029] The housing 20 has side walls 21 facing the stacked bodies 10A, 10B, and 10C in the Y-axis direction. The side walls 21 directly support the stacked bodies 10A, 10B, and 10C from both sides in the Y-axis direction. In this way, the battery pack 1 of this embodiment is a battery pack adopting a Cell-to-Pack structure in which the stacked body 10 including a plurality of battery cells 100 is directly accommodated in the housing.

[0030] The busbar module 30 includes a busbar module 30A (first busbar module) disposed on the stack 10A, a busbar module 30B (second busbar module) disposed on the stack 10B, and a busbar module 30C (third busbar module) disposed on the stack 10C.

[0031] Figure 2 1 is a perspective view showing the structure of a battery cell 100 constituting the stacked bodies 10A, 10B, and 10C. Figure 2 As shown, the battery cell 100 has a square shape and includes an electrode terminal 110 , a frame 120 , and a gas exhaust valve 130 .

[0032] The electrode terminal 110 is formed on the frame 120. The electrode terminal 110 includes a positive terminal 111 and a negative terminal 112 as two electrode terminals 110 arranged along the X-axis direction (second direction) orthogonal to the Y-axis direction (first direction). The positive terminal 111 and the negative terminal 112 are provided to be separated from each other in the X-axis direction.

[0033] The frame 120 has a substantially rectangular parallelepiped shape. An electrode assembly and an electrolyte solution (not shown) are accommodated in the frame 120. The frame 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.

[0034] The upper surface 121 is a plane perpendicular to the Z-axis direction. The electrode terminal 110 is arranged 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).

[0035] Each of the first side surface 123 and the second side surface 124 is formed of a plane orthogonal 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 frame body 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 in which the X-axis direction is the long side direction and the Z-axis direction is the short side direction when viewed in the Y-axis direction.

[0036] The plurality of battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 face each other between the battery cells 100 and 100 adjacent to each other in the Y-axis direction. Thus, the positive terminals 111 and the negative terminals 112 are alternately arranged in the Y-axis direction.

[0037] The gas discharge valve 130 is provided on the upper surface 121 . When the internal pressure of the housing 120 increases to a predetermined value or more due to the gas generated inside the housing 120 , the gas discharge valve 130 opens and discharges the gas to the outside of the housing 120 .

[0038] Next, use Figure 3 and Figure 4 , the basic structure of the busbar module 30 is described. Figure 3 3 is a top view of the plate member 310 included in the busbar module 30 . Figure 4 It is a perspective view showing the structure around the bus bar 320 in the bus bar module 30 .

[0039] The busbar modules 30A, 30B, and 30C respectively include Figure 3 The plate member 310 is shown. Figure 3 As shown, 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 at a position corresponding to the gas exhaust valve 130 of the battery cell 100; and a wall portion 314 that divides the space on the plate member 310 into multiple parts.

[0040] like Figure 4 As shown, busbars 320 are housed in each space separated by the wall portion 314. The busbar 320 is composed of a conductor (typically a metal member). The busbar 320 electrically connects the electrode terminals 110 of multiple battery cells 100 to each other. The busbar 320 includes a root portion 321 extending in the Y-axis direction and a connecting portion 322 (first connecting portion) and a connecting portion 323 (second connecting portion) protruding from the root portion 321 in the X-axis direction. The connecting portions 322 and 323 are respectively connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0041] 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 located at mutually separated positions in the Y-axis direction. The third portion 314C connects the first portion 314A and the second portion 314B.

[0042] The wall portion 314 is formed with a rib 315 and a locking portion 316. The rib 315 protrudes from a position adjacent to the third portion 314C of the wall portion 314 to both sides in the Y-axis direction. The rib 315 positions the adjacent plurality of busbars 320 in the Y-axis direction. The locking portion 316 locks the busbar 320 in the Z-axis direction. The shape or arrangement of the rib 315 and the locking portion 316 is not limited to Figure 4 The structure shown can be modified appropriately.

[0043] The busbar 320 is connected to the wiring 410. The wiring 410 is fixed to the busbar 320 by screws 420. The wiring 410 and the screws 420 are not limited to Figure 4 In the structure shown, for example, wiring can be formed by a flexible wiring substrate.

[0044] The electrode terminal 110 and the bus bar 320 of the battery cell 100 are positioned relative to each other in the X-axis direction and the Y-axis direction and then welded together. By accurately performing this positioning, the welding process of the electrode terminal 110 and the bus bar 320 can be carried out efficiently and with high quality. When the bus bar 320 is accommodated in the space separated by the wall portion 314, it is accurately positioned relative to the plate member 310 in the X-axis direction and the Y-axis direction. Therefore, it is required to position the plate member 310 and the stacked body 10 with high precision.

[0045] use Figures 5 to 8 , a positioning mechanism of the bus bar module 30 (plate member 310) in this embodiment will be described.

[0046] Figure 5 2 is a diagram showing the positioning mechanism of the busbar module 30 in the Y-axis direction. Figure 5 As shown, the plate member 310 of the bus bar module 30 has a positioning mechanism 317 for positioning the bus bar module 30 in the Y-axis direction by applying force to the side wall 21 of the housing 20 .

[0047] Figure 5The positioning mechanism 317 shown is composed of a snap-fit ​​shaped protrusion formed on the end surface 311 of the plate member 310. The protrusion constituting the positioning mechanism 317 protrudes from the end surface 311 of the plate member 310 toward the side wall 21. When the plate member 310 is set in the housing 20, the positioning mechanism 317 presses the side wall 21 of the housing 20 to force the plate member 310 toward a predetermined position. As a result, the busbar module 30 is positioned in the Y-axis direction.

[0048] The positioning mechanism 317 may be provided on the end faces 311 on both sides of the plate member 310 in the Y-axis direction, or may be provided only on the end face 311 on one side of the plate member 310 in the Y-axis direction. In the case where the positioning mechanism 317 is provided on both sides in the Y-axis direction, the plate member 310 is forced toward the center of the housing 20 in the Y-axis direction, and is positioned at a position where the forces applied by the positioning mechanisms 317 on both sides are balanced. In the case where the positioning mechanism 317 is provided on one side in the Y-axis direction, the plate member 310 is forced toward the side wall 21 on the opposite side of the side where the positioning mechanism 317 is provided, and is positioned with the side wall 21 as a reference surface.

[0049] As a reaction to the side wall 21 of the pressing case 20, the protrusion constituting the positioning mechanism 317 is deformed toward the center side of the stacked body 10. At this time, the positioning mechanism 317 is preferably located at a position that does not interfere with the gas discharge valve 130 when viewed from the Z-axis direction. By setting it in this way, the busbar module 30 can be positioned in the Y-axis direction without affecting the gas discharge from the gas discharge valve 130 of the battery cell 100 located at the end in the Y-axis direction.

[0050] Figure 6 It is a perspective view showing the structure between the bus bar module 30 and the upper surface 121 of the battery cell 100 .

[0051] like Figure 6 As shown, the stack 10 includes a spacer 11 disposed between a plurality of battery cells 100. The spacer 11 may be a film or a tape covering the first side 123, the second side 124, and the third side 125 of the battery cell 100. The spacer 11 may also be a film covering the frame 120. The spacer 11 may also be a plate-like member (plate) sandwiched between adjacent battery cells 100. The spacer 11 may also be formed by combining the above-mentioned film or tape with a plate-like member. The spacer 11 has a protrusion 11A protruding toward the plate member 310 side than the plurality of battery cells 100. The plate member 310 has a recess 318 avoiding the protrusion 11A of the spacer 11.

[0052] Figure 7 3 is a perspective view showing the back side of the plate member 310. Figure 7As shown, 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 protruding from the bottom surface 319A of the plate member 310 toward the upper surface 121 of the battery cell 100 is provided on a portion 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. Figure 7 In the example of FIG. 3 , the protruding ribs 319 are intermittently formed on both sides of the through hole 313 so as to extend in the Y-axis direction.

[0053] Figure 8 2 is a diagram showing the positioning mechanism of the busbar module 30 in the X-axis direction. Figure 8 As shown, the busbar module 30 has two adjacent stacked bodies (in Figure 8 In the example of FIG. 1 , the positioning mechanism 330 is provided between the stacked bodies 10A and 10B and performs positioning of the busbar module 30 in the X-axis direction. Figure 8 In the example, the busbar module 30A has a positioning mechanism 330A, and the busbar module 30B has a positioning mechanism 330B, but the scope of the present invention is not limited to all busbar modules 30 having a positioning mechanism 330, and only a part of the multiple busbar modules 30 may have a positioning mechanism 330.

[0054] The positioning mechanism 330A has an insertion portion 331A that is pressed between the stacked bodies 10A and 10B. When the insertion portion 331A is pressed between the stacked bodies 10A and 10B, the busbar module 30A is forced in a direction away from the stacked body 10B. At this time, the insertion portion 331A abuts against the side surface of the stacked body 10A, thereby positioning the busbar module 30A in the X-axis direction.

[0055] The positioning mechanism 330B has an insertion portion 331B that is pressed between the stacked bodies 10A and 10B. When the insertion portion 331B is pressed between the stacked bodies 10A and 10B, the busbar module 30B is forced in a direction away from the stacked body 10A. At this time, the insertion portion 331B abuts against the side surface of the stacked body 10B, thereby positioning the busbar module 30B in the X-axis direction.

[0056] Fig. 9 , Fig.10 It is a diagram showing a modification of the positioning mechanism of the bus bar module 30 in the Y-axis direction.

[0057] Fig. 9 The illustrated positioning mechanism 317A includes an adjuster 317A1 that is inserted into a hole provided in the end surface 311 of the plate member 310 and protrudes from the end surface 311 toward the side wall 21 of the housing 20 . Fig.10The illustrated positioning mechanism 317B includes an elastically deformable expansion and contraction portion 317B1 that projects from the end surface 311 of the plate member 310 toward the side wall 21 of the housing 20 . Fig. 9 , Fig.10 The positioning mechanisms 317A and 317B shown can generate a reaction force to press the side wall 21 of the housing 20 when the plate member 310 approaches the side wall 21 of the housing 20, thereby urging the plate member 310 toward a predetermined position. As a result, the busbar module 30 is positioned in the Y-axis direction.

[0058] As described above, the battery pack 1 of this embodiment adopts a cell-to-pack structure in which the stack 10 including the plurality of battery cells 100 is directly housed in the case 20 . Therefore, members such as restraint bars in the module structure cannot be used as members for positioning the busbar module 30 .

[0059] In the battery pack 1 of this embodiment, the busbar module 30 can be positioned in the Y-axis direction by applying force to the side wall 21 of the shell 20 through the positioning mechanism 317 provided on the plate member 310. Therefore, in the battery pack 1 with a Cell-to-Pack structure, the busbar module 30 can be positioned with high precision without providing a complex mechanism.

[0060] In the battery pack 1, the protruding rib 319 protruding from the bottom surface 319A of the plate member 310 toward the battery cell 100 abuts against the upper surface 121 of the battery cell 100. In this way, by making the protruding rib 319 abut against the battery cell 100, the contact area between the plate member 310 and the upper surface 121 of the battery cell 100 can be reduced, and the friction resistance when the plate member 310 moves relative to the battery cell 100 can be reduced, so that the plate member 310 can be positioned smoothly and accurately.

[0061] In addition, the shape and arrangement of the protruding rib 319 are not limited to Figure 7 In addition,

[0062] In the present invention, the protruding rib 319 is not necessarily an essential structure.

[0063] In the battery pack 1, the plate member 310 has the recessed portion 318 avoiding the protruding portion 11A of the spacer 11. Therefore, when the plate member 310 is positioned in the Y-axis direction by the positioning mechanism 317, the movement of the plate member 310 in the Y-axis direction is not hindered by the protruding portion 11A of the spacer 11. Therefore, the plate member 310 can be positioned smoothly and accurately.

[0064] However, in the present invention, the protrusion 11A of the spacer 11 and the recess 318 of the plate member 310 are not necessarily essential structures.

[0065] The battery pack 1 is provided with a positioning mechanism 330 inserted between the stacked bodies 10A and 10B to position the bus bar modules 30A and 30B in the X-axis direction. Therefore, the plate member 310 can be positioned in the X-axis direction in addition to the Y-axis direction.

[0066] However, in the present invention, the X-axis direction positioning mechanism 330 is not necessarily a necessary structure. In addition, all of the plurality of busbar modules 30A, 30B, 30C may be equipped with the positioning mechanism 330, or a part of the plurality of busbar modules 30A, 30B, 30C may be equipped with the positioning mechanism 330.

[0067] According to the present invention, since a first positioning mechanism is provided for positioning the busbar module in the stacking direction (first direction) of the battery cells by pressing the side wall of the shell, the busbar module can be positioned with high precision even in a battery pack of a Cell-to-Pack structure in which a stack including a plurality of battery cells is directly accommodated in a shell.

[0068] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery pack, wherein: The battery pack has: a stack including a plurality of battery cells arranged in a first direction; a housing having a side wall facing the stacked body from the first direction and accommodating the stacked body; as well as a busbar module disposed on the stacked body, comprising a busbar for electrically connecting the plurality of battery cells and a plate member for accommodating the busbar; The plate member includes a first positioning mechanism for positioning the bus bar module in the first direction by applying force to the side wall of the housing.

2. The battery pack according to claim 1, wherein: The plurality of battery cells each have an upper surface facing the plate member, The plate member has a bottom surface facing the upper surfaces of the plurality of battery cells. A protruding rib protruding from the bottom surface of the plate member toward the upper surfaces of the plurality of battery cells is provided on a portion of the bottom surface of the plate member, and the protruding rib abuts against the upper surfaces of the plurality of battery cells.

3. The battery pack according to claim 2, wherein: Each of the plurality of battery cells includes a frame including the upper surface and a discharge valve provided on the upper surface and opened when the internal pressure of the frame increases. The first positioning mechanism is located at a position that does not interfere with the discharge valve in a state of pressing the side wall of the housing.

4. The battery pack according to claim 1 or 2, wherein: The stacked body includes a spacer disposed between the plurality of battery cells, The spacer has a protrusion that protrudes toward the plate member side from the plurality of battery cells. The plate member has a recessed portion avoiding the protruding portion of the spacer.

5. The battery pack according to claim 1 or 2, wherein: The stacked body includes a first stacked body and a second stacked body adjacent to the first stacked body in a second direction orthogonal to the first direction, The first stack and the second stack respectively include the plurality of battery cells and are respectively facing the side wall from the first direction. The busbar module includes a first busbar module and a second busbar module respectively arranged on the first stack and the second stack. The first busbar module and the second busbar module respectively include the busbar and the plate member, At least one of the first bus bar module and the second bus bar module includes a second positioning mechanism that is inserted between the first stacked body and the second stacked body and positions the first bus bar module or the second bus bar module in the second direction.

Images