Batteries and battery packs

Abstract

Provided is a battery assembly and a battery pack that enable accurate positioning of a bus bar module while maintaining the installation space for battery cells. The battery pack includes a stack including a plurality of battery cells arranged in a first direction, a busbar module provided on the stack, and a fitting member that fits onto an end of a housing of at least one of the plurality of battery cells in a second direction perpendicular to the first direction. The fitting member has an engaging portion that engages with the busbar module to position the busbar module relative to the stack in at least the first direction.

Description

[Technical Field]

[0001] The present technology relates to a battery assembly and a battery pack. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2019-220437 (Patent Document 1) discloses a structure in which a bus bar plate (24) is provided on a stack (2) of multiple battery cells (21) and insulating plates (22), and the protruding portion (221) of the insulating plate (22) is used as a fixing device for the bus bar plate (24). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-220437 Summary of the Invention [Problem to be solved by the invention]

[0004] It is necessary to accurately position the busbar module relative to the stack of battery cells. Depending on the configuration of the battery pack, it may be difficult to install a positioning mechanism. From the perspective of improving energy density, it is necessary to install a positioning mechanism without compromising the installation space for the battery cells. From these perspectives, there is still room for improvement in conventional battery packs.

[0005] An object of the present technology is to provide a battery assembly and a battery pack that can accurately position a bus bar module while maintaining the installation space for battery cells. [Means for solving the problem]

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

[0007] [1] A battery pack comprising: a stack including a plurality of battery cells arranged in a first direction, each having a housing for housing an electrode body; a bus bar module provided on the stack; and a fitting member that fits into an end of the housing of at least one of the plurality of battery cells in a second direction perpendicular to the first direction, the fitting member having an engaging portion that engages with the bus bar module to position the bus bar module relative to the stack in at least the first direction.

[0008] [2] The battery pack described in [1], wherein the busbar module includes a plate member having a side portion and a protrusion protruding from the side portion of the plate member in a third direction perpendicular to the first direction and the second direction, and the protrusion engages with the engaging portion of the fitting member.

[0009] [3] The battery pack according to [1] or [2], wherein the fitting member is made of a sheet member having a thickness of 0.5 mm or less.

[0010] [4] The battery pack according to any one of [1] to [3], further comprising separators arranged between the plurality of battery cells, and the fitting members are arranged spaced apart from the separators in the second direction.

[0011] [5] A battery pack comprising: the battery pack according to any one of [1] to [4]; and a case having a side wall defining an internal space and accommodating the battery pack in the internal space, wherein the side wall directly supports the stack in the battery pack from the first direction. [Effects of the Invention]

[0012] According to the present technology, it is possible to provide a battery assembly and a battery pack that can accurately position the bus bar module while maintaining the installation space for the battery cells. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 2 is an exploded perspective view of the battery pack according to the embodiment. [Figure 2] FIG. 2 is a perspective view of a battery cell according to an embodiment. [Figure 3] FIG. 2 is a top view of a plate member of the bus bar module according to the embodiment. [Figure 4] FIG. 10 is a perspective view showing the state before fitting members are attached to the battery cell. [Figure 5] FIG. 10 is a perspective view showing the state after fitting members have been attached to the battery cells. [Figure 6] FIG. [Figure 7] FIG. 2 is a cross-sectional view of a battery cell in a battery pack to which a fitting member is attached. [Figure 8] 10 is an enlarged view of a portion where an engaging portion of a fitting member engages with a protruding portion of a bus bar module. FIG. [Figure 9] FIG. 10 is a diagram (part 1) showing an example of the arrangement of protrusions in a busbar module. [Figure 10] FIG. 10 is a diagram (part 2) showing an example of the arrangement of protrusions in the busbar module. [Figure 11] FIG. 10 is a diagram (part 3) showing an example of the arrangement of protrusions in the busbar module. DETAILED DESCRIPTION OF THE INVENTION

[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 may not be repeated.

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

[0016] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0017] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," 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 a single state, and the relative positional relationships can be reversed 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 "electrode" may collectively refer to positive and negative electrodes. Furthermore, the term "electrode plate" may collectively refer to positive and negative plates.

[0019] In this specification, a "battery cell" can be installed in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of a "battery cell" is not limited to in-vehicle use.

[0020] In this embodiment, the Y-axis direction is referred to as the “first direction,” the Z-axis direction is referred to as the “second direction,” and the X-axis direction is referred to as the “third direction.” The Y-axis, Z-axis, and X-axis are perpendicular to each other.

[0021] 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 the Y-axis direction, a case 20 that houses the stack 10, and a bus bar module 30 arranged on the stack 10.

[0022] The laminate 10 includes a laminate 10A (first laminate), a laminate 10B (second laminate), and a laminate 10C (third laminate). The laminate 10A and the laminate 10B are adjacent to each other in the X-axis direction. The laminate 10B and the laminate 10C are adjacent to each other in the X-axis direction. The number of laminates 10 can be changed as appropriate.

[0023] The case 20 has side walls 21 that face the stack 10A, the stack 10B, and the stack 10C in the Y-axis direction. The side walls 21 define the internal space of the case 20 that houses the stack 10. The side walls 21 directly support the stack 10A, the stack 10B, and the stack 10C from both sides in the Y-axis direction. In this way, the battery pack 1 according to this embodiment employs a cell-to-pack structure in which the stack 10, which includes a plurality of battery cells 100, is housed directly in the case.

[0024] 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. In this embodiment, the busbar module 30A, the busbar module 30B, and the busbar module 30C have the same shape, but may have different shapes.

[0025] 2 is a perspective view showing the configuration of the battery cells 100 that make up the laminate 10A, laminate 10B, and laminate 10C. As shown in FIG. 2, the battery cells 100 have a rectangular shape. The battery cells 100 have electrode terminals 110, a housing 120, and a gas release valve 130.

[0026] The electrode terminals 110 are formed on the housing 120. The electrode terminals 110 include a positive terminal 111 and a negative terminal 112, which are arranged along the X-axis direction perpendicular to the Y-axis direction. The positive terminal 111 and the negative terminal 112 are spaced apart from each other in the X-axis direction.

[0027] The housing 120 has a substantially rectangular parallelepiped shape. An electrode assembly and an electrolyte (not shown) are housed 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 pair of third side surfaces 125.

[0028] The upper surface 121 is a flat surface 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, which is perpendicular to the Y-axis direction and the X-axis direction.

[0029] Each of the first side surface 123 and the second side surface 124 is made 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 when viewed in the Y-axis direction, with the X-axis direction being the longitudinal direction and the Z-axis direction being the lateral direction.

[0030] 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.

[0031] Gas exhaust valve 130 is provided on top surface 121. When the internal pressure of housing 120 rises 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.

[0032] 3 is a top view of a plate member 300 included in the bus bar module 30. The bus bar module 30A, the bus bar module 30B, and the bus bar module 30C each include the plate member 300 shown in FIG.

[0033] As shown in FIG. 3, the plate member 300 includes an end face 310 located at the end in the Y-axis direction, an end face 320 located at the end in the X-axis direction, a through hole 330, and a wall portion 340 that divides the space on the plate member 300 into multiple sections.

[0034] The through holes 330 are formed at positions corresponding to the gas release valves 130 of the battery cells 100. Bus bars (not shown) are housed in each space separated by the wall portions 340. The bus bars electrically connect the electrode terminals 110 of the multiple battery cells 100 to one another.

[0035] Plate member 300 is preferably made of a resin material such as polypropylene (PP) or polybutylene terephthalate (PBT). The thickness of plate member 300 is preferably about 0.5 mm to 1.0 mm. However, the material and thickness of plate member 300 are not limited to the above ranges.

[0036] In the battery pack 1 according to the present embodiment, a fitting member 40 shown in Figures 4 to 6 is used as a positioning mechanism for positioning the bus bar modules 30A, 30B, and 30C relative to the laminates 10A, 10B, and 10C, respectively.

[0037] Fig. 4 shows the state before the fitting member 40 is attached to the battery cell 100, and Fig. 5 shows the state after the fitting member 40 has been attached to the battery cell 100. Fig. 6 is a perspective view showing the fitting member 40 removed from the battery cell 100.

[0038] 4 and 5, the fitting member 40 fits into the upper end of the casing 120 of the battery cell 100 from the Z-axis direction (the end on the electrode terminal 110 side in the Z-axis direction). The fitting member 40 has an engagement portion 41 (receptacle portion) for positioning and an opening 42. The casing 120 of the battery cell 100 fits into the inner periphery of the opening 42.

[0039] In the examples of FIGS. 4 to 6, the engaging portion 41 is provided on only one side in the X-axis direction, but the engaging portion 41 may be provided on both sides in the X-axis direction.

[0040] The fitting member 40 can be attached to any one of the battery cells 100 that make up each of the stacks 10A, 10B, and 10C.

[0041] The fitting member 40 is preferably made of an insulating sheet member that is thinner than the plate member 300. The engaging portion 41 of the fitting member 40 is preferably formed by compression molding or vacuum molding.

[0042] The fitting member 40 is preferably made of a flame-retardant material. Examples of flame-retardant materials include polyvinyl chloride (PVC), polypropylene (PP), and polycarbonate (PC). The sheet material constituting the fitting member 40 preferably has a thickness of approximately 0.5 mm or less. However, the material and thickness of the fitting member 40 are not limited to the above ranges.

[0043] Fig. 7 is a cross-sectional view of a battery cell 100 to which a fitting member 40 is attached. As shown in Fig. 7, in a stack 10 in which multiple battery cells 100 are arranged in the Y-axis direction, separators 200 are provided on both sides of the battery cells 100 (between adjacent battery cells 100). In the example of Fig. 7, the separators 200 are provided in the range in the Z-axis direction where the electrode body 140 of the battery cell 100 abuts against the inner surface of the casing 120. However, the separators 200 may be formed longer or shorter in the Z-axis direction than in the state shown in Fig. 7.

[0044] The upper end of the separator 200 is arranged to terminate at a position below the upper surface 121 of the battery cell 100. Therefore, at the end of the battery cell 100 on the upper surface 121 side, a gap is formed that is the thickness of the separator 200, in which the fitting member 40 is to be installed.

[0045] 7, the fitting member 40 includes a fitting portion 43 that fits into the housing 120 of the battery cell 100, and a folded portion 44 that is folded over the top surface 121 of the battery cell 100. By providing the folded portion 44 on the top surface 121 of the battery cell 100, the fitting member 40 can be stably fixed to the battery cell 100. However, the folded portion 44 is not necessarily provided.

[0046] 7, the lower end of the fitting portion 43 is provided so as not to interfere with the separator 200. In other words, the fitting member 40 is provided spaced apart from the separator 200 in the Z-axis direction.

[0047] 8 is an enlarged perspective view showing the periphery of the engaging portion 41 of the fitting member 40. As shown in Fig. 8, the plate member 300 has a protruding portion 360 that protrudes in the X-axis direction from the end face 320 (side portion). The protruding portion 360 engages with the engaging portion 41 of the fitting member 40, thereby positioning the busbar module 30 relative to the laminate 10.

[0048] The housing 120 of the battery cell 100 may be covered with an insulating film 50. The fitting member 40 and the film 50 may be provided so as to protrude further toward the plate member 300 than the upper surface 121 of the battery cell 100 in the Z-axis direction. The plate member 300 arranged on the upper surface 121 of the battery cell 100 may have a recess 350 that allows the fitting member 40 and the film 50 to pass through, as shown in FIG.

[0049] In the battery pack 1 according to this embodiment, the stack 10 is directly supported by the side wall 21 of the case 20, and therefore no end plates or restraining members are provided. Furthermore, if an intermediate plate were provided midway in the Y-axis direction of the stack 10, the storage space for the battery cells 100 would be occupied by the intermediate plate, and the energy density of the battery pack 1 would decrease.

[0050] In the battery pack 1 according to this embodiment, as described above, the busbar module 30 can be accurately positioned relative to the stack 10 by engaging the fitting members 40 attached directly to the battery cells 100 with the busbar modules 30. Furthermore, the fitting members 40 are arranged so as not to interfere with the separators 200 and to fit within the thickness of the separators 200 in the Y-axis direction, so providing the fitting members 40 does not reduce the installation space for the battery cells 100. This makes it possible to accurately position the busbar modules 30 while maintaining the installation space for the battery cells 100.

[0051] The scope of this technology is not necessarily limited to a cell-to-pack structure, but may also be applied to a cell-to-body structure or a cell-to-chassis structure. Furthermore, this technology may also be applied to a cell-module-pack structure.

[0052] Next, examples of the arrangement of the protrusions 360 on the plate member 300 of the bus bar module 30 will be described with reference to FIGS.

[0053] As shown in Fig. 9, only one protrusion 360 may be provided on one plate member 300, as shown in Fig. 10, two protrusions 360 may be provided on one plate member 300, or three protrusions 360 may be provided on one plate member 300 as shown in Fig. 11. Four or more protrusions 360 may be provided on one plate member 300. In either case, the busbar module 30 is positioned relative to the laminate 10 at least in the Y-axis direction.

[0054] 10 and 11, by providing protrusions 360 on both sides in the X-axis direction, it is possible to position the plate member 300 in the Y-axis direction and also to suppress rotation (around the Z-axis) of the plate member 300. When providing protrusions 360 on both sides in the X-axis direction, the positions in the Y-axis direction may be aligned as shown in Fig. 10, or the positions in the Y-axis direction may be different as shown in Fig. 11.

[0055] In the present embodiment, the gas release valve 130 and the electrode terminal 110 are arranged on the same surface of the housing 120, but the scope of the present technology is not limited thereto, and the gas release valve 130 and the electrode terminal 110 may be arranged on different surfaces of the housing 120. Furthermore, the electrode terminal 110 may be arranged on a surface other than the upper surface 121 (for example, the lower surface 122 or the third side surface 125), and the positive electrode terminal 111 and the negative electrode terminal 112 may be arranged on different surfaces of the housing 120 (for example, each of the pair of third side surfaces 125).

[0056] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be 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 meaning and scope of the claims. [Explanation of symbols]

[0057] 1 battery pack, 10, 10A, 10B, 10C laminate, 20 case, 21 side wall, 30, 30A, 30B, 30C bus bar module, 40 fitting member, 41 engagement portion, 42 opening, 43 fitting portion, 44 folded portion, 50 film, 100 battery cell, 110 electrode terminal, 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 release valve, 140 electrode body, 200 separator, 300 plate member, 310, 320 end surface, 330 through hole, 340 wall portion, 350 recess, 360 protrusion.

Claims

1. a stack including a plurality of battery cells arranged in a first direction, each of the battery cells having a housing for housing an electrode assembly; a bus bar module provided on the laminate; a fitting member that fits into an end of the housing of at least one of the plurality of battery cells in a second direction that is perpendicular to the first direction; The fitting member has an engaging portion that engages with the bus bar module to position the bus bar module relative to the stack in at least the first direction.

2. the bus bar module includes a plate member having a side portion and a protrusion protruding from the side portion of the plate member in a third direction perpendicular to the first direction and the second direction; The battery pack according to claim 1 , wherein the protrusion engages with the engaging portion of the fitting member.

3. 3. The battery pack according to claim 1, wherein the fitting member is made of a sheet member having a thickness of 0.5 mm or less.

4. The battery pack further includes separators disposed between the plurality of battery cells.

3. The battery pack according to claim 1, wherein the fitting members are spaced apart from the separators in the second direction.

5. A battery pack, The battery pack according to claim 1 or 2; a case having a sidewall defining an internal space and accommodating the battery pack in the internal space; The side wall directly supports the stack of the battery pack from the first direction.

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