Battery Module

Abstract

To provide a battery module capable of absorbing large swelling force while stably ensuring electrical insulation properties between adjacent battery cells.SOLUTION: A battery module includes a plurality of battery cells arranged along a first direction, and separator members each provided between the battery cells. The separator members each include a first portion and a second portion abutting against the battery cells from the first direction, the second portion being easier to deform than the first portion and having insulating properties. The first portion is formed on both sides of at least the second portion in a plane direction perpendicular to the first direction. The separator members each have a structure where the second portion is located on both sides of the first portion in the first direction, or a structure where the second portion includes an opening penetrating through an overall thickness of the separator member in the first direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present technology relates to a battery module. [Background technology]

[0002] Battery modules in which multiple battery cells are stacked are known. Separator members provided between the multiple battery cells are required to ensure electrical insulation between adjacent battery cells and to absorb expansion of the battery cells when the battery cells expand. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-207553 A [Patent Document 2] JP 2015-225700 A [Patent Document 3] JP 2016-091871 A [Patent Document 4] JP 2014-072055 A [Patent Document 5] International Publication No. 2019 / 155713 [Patent Document 6] China Utility Model Publication No. 206059484 [Patent Document 7] JP 2014-010983 A [Patent Document 8] International Publication No. 2018 / 155506 [Patent Document 9] International Publication No. 2018 / 207608 [Patent Document 10] Japanese Patent Application Publication No. 07-122252 Summary of the Invention [Problem to be solved by the invention]

[0004] In high-output battery cells, the swelling force tends to be large, and conventional separator members still do not have a sufficient structure from the viewpoint of absorbing the large swelling force while stably ensuring electrical insulation between adjacent battery cells.

[0005] An object of the present technology is to provide a battery module that is capable of absorbing a large swelling force while stably ensuring electrical insulation between adjacent battery cells. [Means for solving the problem]

[0006] A battery module according to the present technology includes a plurality of battery cells arranged along a first direction, and a separator member provided between the plurality of battery cells. The separator member includes a first portion and a second portion that contacts the plurality of battery cells from the first direction, is more deformable than the first portion, and has insulating properties. The first portion is formed on at least both sides of the second portion in a planar direction perpendicular to the first direction. The separator member has a structure in which the second portions are located on both sides of the first portion in the first direction, or a structure in which the second portions include an opening that penetrates the entire thickness of the separator member in the first direction. Effect of the Invention

[0007] According to the present technology, the second part, which is more easily deformed than the first part, absorbs the expansion force of the battery cell along the first direction, and the first part, which is formed on at least both sides of the second part in a planar direction perpendicular to the first direction, can stably ensure electrical insulation between adjacent battery cells.

[0008] In a structure in which the second portions are located on both sides of the first portion in the first direction, electrical insulation can be stably ensured by the first portion located between the second portions.

[0009] In a structure in which the second portion includes an opening penetrating the entire thickness of the separator member in the first direction, the swelling force of the battery cell can be efficiently absorbed by the second portion. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view of a battery module. [Diagram 2] FIG. 2 is an exploded perspective view of the battery module according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view of the separator member shown in FIG. 2. [Figure 4] FIG. 3 is an exploded perspective view of the separator member shown in FIG. 2. [Diagram 5] 4 is a cross-sectional view of FIG. 3 . [Figure 6] FIG. 11 is an exploded perspective view of a battery module according to a second embodiment. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 1 is a diagram showing an example of a honeycomb structure. [Figure 9] 9 is a diagram showing a state in which the honeycomb structure shown in FIG. 8 is deformed by the expansion force of a battery cell. [Figure 10] FIG. 11 is a diagram showing another example of a honeycomb structure. [Figure 11] FIG. 11 is a diagram showing yet another example of a honeycomb structure. [Figure 12] FIG. 11 is a diagram showing yet another example of a honeycomb structure. [Figure 13] FIG. 11 is a diagram showing yet another example of a honeycomb structure. [Figure 14] 11A and 11B are diagrams showing modified examples of the cross section of the wall of the honeycomb structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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).

[0015] In this specification, the term "battery" is not limited to lithium ion batteries, but may include other batteries such as nickel-metal hydride batteries.

[0016] Fig. 1 is a perspective view of a battery module according to embodiments 1 and 2 described below. As shown in Fig. 1, the battery module 1 includes battery cells 100 and separator members 200. The battery cells 100 and the separator members 200 are arranged alternately along the Y-axis direction (first direction).

[0017] The battery cells 100 are rectangular battery cells, and a plurality of battery cells 100 are provided along the Y-axis direction. The plurality of battery cells 100 are electrically connected to each other via bus bars (not shown).

[0018] The separator member 200 is provided between multiple battery cells 100. The separator member 200 prevents unintended electrical conduction between adjacent battery cells 100. The separator member 200 ensures electrical insulation between adjacent battery cells 100.

[0019] (Embodiment 1) 2 is an exploded perspective view of the battery module 1 according to Embodiment 1. As shown in FIG.

[0020] The first portion 210 has a higher rigidity than the second portion 220. The first portion 210 may constitute a frame portion of the separator member 200. The first portion 210 may be made of, for example, a hard resin, a metal, or the like.

[0021] The first portion 210 according to this embodiment is formed so as to surround the entire circumference of the second portion 220 in a plane (XZ plane) perpendicular to the Y axis direction. The first portion 210 only needs to be formed so as to be located on both sides of the second portion 220 in the XZ plane direction, and does not necessarily have to be formed so as to surround the entire circumference of the second portion 220.

[0022] The battery cell 100 includes a case body 110 that houses the electrode assembly, and a sealing plate 120 that is welded to the case body 110 so as to seal an opening of the case body 110. In the example of Fig. 2, a first portion 210 of the separator member 200 abuts against the case body 110 at a position corresponding to the welded portion with the sealing plate 120.

[0023] The second portion 220 has a lower rigidity than the first portion 210, and is more easily deformed than the first portion 210. The second portion 220 may constitute a deformation absorbing portion of the separator member 200 (a portion that absorbs the expansion force of the battery cell 100). The second portion 220 may be made of an insulating material such as soft resin, rubber, urethane, or silicon. The second portion 220 may include a space. The second portion 220 according to this embodiment may be made of a honeycomb structure, which will be described later in the second embodiment.

[0024] The second portion 220 can absorb the expansion of the battery cell 100 by elastic deformation. The second portion 220 can be made of a superelastic body. The second portion 220 can be used with a compression ratio in the range of about 0.5 to 1.0. Even if the second portion 220 is compressed to about half its thickness (height in the Y-axis direction), it can instantly return to its original thickness when the compression load is released.

[0025] Fig. 3 is a perspective view of the separator member 200 shown in Fig. 2. Fig. 4 is an exploded perspective view of the separator member. Fig. 5 is a cross-sectional view taken along line VV in Fig. 3.

[0026] As shown in Figs. 3 to 5, the separator member 200 has a structure in which the second portions 220 are located on both sides of the first portion 210 in the Y-axis direction. In the structure shown in Figs. 3 to 5, the swelling force of the battery cells 100 is absorbed by the second portions 220 that abut against the battery cells 100 at the center in the X-axis direction (second direction) and the Z-axis direction (third direction), while the distance between the battery cells 100 is ensured by the first portions 210 that abut against the battery cells 100 at the outer periphery in the X-axis direction (second direction) and the Z-axis direction (third direction), thereby ensuring electrical insulation. Furthermore, even if the swelling force of the battery cells 100 increases, the first portions 210 that are located between the second portions 220 in the Y-axis direction (first direction) ensure electrical insulation between the battery cells 100.

[0027] (Embodiment 2) Fig. 6 is an exploded perspective view of a battery module according to embodiment 2. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. As shown in Figs. 6 and 7, in the present embodiment as well, a separator member 200 includes a first portion 210 and a second portion 220.

[0028] The following describes characteristic features of the separator member 200 according to the present embodiment. Detailed description of the same parts as those in the first embodiment will not be repeated.

[0029] The separator member 200 according to the present embodiment has a structure in which the second portion 220 includes an opening 220A that penetrates the entire thickness of the separator member 200 in the Y-axis direction (first direction). More specifically, the separator member 200 includes a honeycomb structure.

[0030] Fig. 8 is a diagram showing an example of a honeycomb structure, and Fig. 9 is a diagram showing a state in which the honeycomb structure shown in Fig. 8 has been deformed by the expansion force of the battery cell 100.

[0031] The honeycomb structure of the second portion 220 shown in Fig. 8 has a structure in which regular hexagons of uniform size are arranged. The honeycomb structure is configured to be able to absorb the expansion of the battery cell 100. If the expansion of the battery cell 100 is relatively small, the second portion 220 can also be made of resin. If the expansion of the battery cell 100 is relatively large, it is preferable to configure the second portion 220 from a superelastic body.

[0032] The second portion 220 is provided in a range that does not exceed the width of the case body 110 of the battery cell 100 in the X-axis and Z-axis directions. The honeycomb structure of the second portion 220 is formed in a shape that is linearly symmetric with respect to the X-axis and Z-axis directions. That is, the width of the second portion 220 in the X-axis direction is set to be an integer multiple of the radius of the circumscribing circle of the regular hexagon that constitutes the honeycomb structure, and the width of the second portion 220 in the Z-axis direction is set to be √3 × an integer multiple of the radius of the circumscribing circle of the regular hexagon that constitutes the honeycomb structure.

[0033] 9, when the honeycomb structure of the second portion 220 is deformed by the expansion force of the battery cells 100, the central portion 222 deforms more than the peripheral portion 221. This is because the expansion of the battery cells 100 is greater in the central portion 222 than in the peripheral portion 221.

[0034] Next, modified examples of the honeycomb structure will be described with reference to Fig. 10 to Fig. 14. The honeycomb structure according to the modified example shown in Fig. 10 and Fig. 11 has a structure in which honeycombs are densely formed in outer peripheral portions 221 located at both ends in the Z-axis direction, and honeycombs are sparsely formed in a central portion 222 sandwiched between the outer peripheral portions 221. This makes it easier to deform the honeycomb structure in the central portion 222 where the deformation of the battery cell 100 is large.

[0035] The outer circumferential portion 221 may be provided so as to surround the entire periphery of the central portion 222. The outer circumferential portion 221 may be provided only on both ends in the X-axis direction of the second portion 220. The outer circumferential portion 221 may be provided discontinuously.

[0036] As in the examples of Figures 10 and 11, when the honeycomb of the peripheral portion 221 is densely configured, the rigidity of the peripheral portion 221 is higher than that of the central portion 222, so that it is not necessarily necessary to separately provide the first portion 210 having higher rigidity, and the peripheral portion 221 can substitute for the first portion 210.

[0037] In the honeycomb structure according to the modification shown in Figures 12 and 13, the orientation of the regular hexagons constituting the honeycomb is different from that of the examples shown in Figures 8 and 9. The shape and orientation of the regular polygons constituting the honeycomb can be changed as appropriate.

[0038] Fig. 14 is a diagram showing a modified example of the cross section of a honeycomb structure. As shown in Fig. 14, the wall thickness of the honeycomb constituting the second portion 220 may be changed along the Y-axis direction. In the example of Fig. 14, the wall thickness of the honeycomb changes in a tapered shape from one end (thickness T1) to the other end (thickness T2) along the Y-axis direction. For example, when the wall thickness of the honeycomb is constant along the Y-axis direction, T1 is about 0.6T or more and 1.0T or less, and T2 is about 1.0T or more and 1.4T or less, where T is the thickness.

[0039] 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]

[0040] 1 battery module, 100 battery cell, 110 case body, 120 sealing plate, 200 separator member, 210 first portion, 220 second portion, 220A opening, 221 outer peripheral portion, 222 central portion.

Claims

1. A plurality of battery cells arranged along a first direction; a separator member provided between the plurality of battery cells; The separator member is A first portion; and a second portion that contacts the plurality of battery cells from the first direction, that is more deformable than the first portion, and that has insulating properties; The first portion is formed on at least both sides of the second portion in a planar direction perpendicular to the first direction, the separator member has a structure in which the second portion is located on both sides of the first portion in the first direction, or a structure in which the second portion includes an opening penetrating an entire thickness of the separator member in the first direction, each of the plurality of battery cells includes a case body that houses an electrode assembly and a sealing plate that is welded to the case body so as to seal an opening of the case body; the first portion abuts against the case body from the first direction at a position corresponding to a welded portion with the sealing plate.

2. the separator member includes a honeycomb structure; The battery module according to claim 1 , wherein the honeycomb structure includes a central portion where the honeycomb is sparsely formed and an outer peripheral portion where the honeycomb is densely formed.

3. The battery module according to claim 1 , wherein the second portion absorbs expansion of the plurality of battery cells by elastic deformation.

4. The battery module according to claim 1 , wherein the plurality of battery cells are rectangular battery cells.

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