Battery module and battery pack

Abstract

To obtain a battery module and a battery pack capable of absorbing the thermal expansion of a battery cell.SOLUTION: A battery module 11 includes a plurality of battery cells 20 arranged inside a housing, and buffer members 32, 34 arranged between adjacent battery cells 20 and at least one of the battery cells 20, with the arrangement direction of the battery cells 20 as the thickness direction, and are formed such that the reaction force acting on the battery cells 20 is smaller at the centers 32A, 34A than the peripheral ends 32B, 34B.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] Patent Document 1 discloses a battery pack in which a heat insulating cushioning material is arranged between each stacked battery cell. In the battery pack described in Patent Document 1, by arranging the heat insulating cushioning material between the battery cells, it is possible to prevent the battery cells from directly rubbing against each other during transportation of the product, and also to provide thermal insulation between the battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-163932 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in order to improve the amount of stored electricity per unit area of ​​a battery module, it is necessary to arrange the battery cells without any gaps, but the battery pack described in the above Patent Document 1 cannot absorb the thermal expansion of the battery cells. In particular, the central portion of a battery cell swells in the thickness direction when it thermally expands, but the battery pack described in the above Patent Document 1 does not take such thermal expansion of the battery cells into consideration, leaving room for improvement.

[0005] In consideration of the above, an object of the present invention is to provide a battery module and a battery pack capable of absorbing the thermal expansion of battery cells. [Means for solving the problem]

[0006] The battery module of claim 1 comprises a plurality of battery cells housed in an arranged state inside a housing, and a cushioning member arranged at least either between adjacent battery cells or between the battery cells and an inner wall of the housing, with the arrangement direction of the battery cells being the thickness direction, and formed so that the reaction force acting on the battery cells is smaller at the center than at the peripheral ends.

[0007] In the battery module according to claim 1, a plurality of battery cells are housed in an array inside a housing. A cushioning member is disposed at least either between adjacent battery cells or between the battery cells and the inner wall of the housing. Here, the cushioning member has a thickness direction that is the same as the array direction of the battery cells, and is formed so that the reaction force acting on the battery cells is smaller at the center of the cushioning member than at the peripheral ends. As a result, when the battery cells thermally expand and the central portions of the battery cells swell, the reaction force acting from the cushioning member on the battery cells can be made approximately uniform between the center and the peripheral ends, and the thermal expansion of the battery cells can be absorbed by the cushioning member.

[0008] A battery module according to a second aspect of the present invention is the battery module according to the first aspect, wherein the cushioning member is disposed at least in a central portion of the casing in a direction in which the battery cells are arranged.

[0009] In the battery module according to claim 2, by arranging the buffer member in the center of the arrangement direction of the battery cells, where the greatest stress is exerted due to the thermal expansion of the battery cells, the thermal expansion of the battery module as a whole can be effectively absorbed.

[0010] A battery module according to a third aspect of the present invention is the battery module according to the first aspect, wherein the cushioning member is formed so that the thickness of the central portion is thinner than that of the peripheral end portions.

[0011] In the battery module of claim 3, by making the thickness of the central part of the cushioning member thinner than the peripheral ends, the reaction force acting from the central part of the cushioning member to the battery cell can be made smaller than the reaction force acting from the peripheral ends of the cushioning member to the battery cell.

[0012] A battery module according to a fourth aspect of the present invention is the battery module according to the first aspect, wherein the cushioning member is formed so that the density of the central portion is lower than that of the peripheral end portions.

[0013] In the battery module of claim 4, by making the density of the central part of the cushioning member lower than that of the peripheral ends, the reaction force acting from the central part of the cushioning member to the battery cell can be made smaller than the reaction force acting from the peripheral ends of the cushioning member to the battery cell.

[0014] A battery module according to a fifth aspect of the present invention is the battery module according to the first aspect, wherein the buffer members are disposed at least between the battery cells and inner walls on both sides of the housing.

[0015] In the battery module according to claim 5, by disposing buffer members between the battery cells and the inner walls on both sides of the housing, it is possible to reduce the reaction force acting from the inner walls of the housing to the battery cells.

[0016] The battery module according to claim 6 is based on claim 5, and further includes a central thick cushioning member disposed in a central portion of the casing in the arrangement direction of the battery cells, the central portion being thicker than the peripheral ends.

[0017] In the battery module according to claim 6, thermal expansion is absorbed by the cushioning members disposed between the battery cells and the inner walls on both sides of the housing, while the central thick cushioning member disposed in the central portion in the arrangement direction of the battery cells curves the central portion of the battery cells. This makes it possible to bend the terminals extending from the ends of the battery cells toward the center in the arrangement direction of the battery cells, thereby suppressing stress concentration on the terminals.

[0018] A battery pack according to a seventh aspect of the present invention includes a plurality of battery modules according to any one of the first to sixth aspects of the present invention.

[0019] In the battery pack according to claim 7, the thermal expansion of the battery cells is absorbed in the plurality of battery modules, thereby improving the reliability of the battery pack as a whole. Effect of the Invention

[0020] As described above, the battery module and battery pack according to the present invention can absorb the thermal expansion of the battery cells. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic plan view showing a main part of a vehicle to which a battery pack according to a first embodiment is applied. [Diagram 2] FIG. 2 is a schematic perspective view of a battery module. [Diagram 3] FIG. 2 is a plan view of the battery module with the top cover removed. [Figure 4] 3 is a schematic diagram of a battery cell accommodated in a battery module as viewed from the thickness direction. FIG. [Diagram 5] FIG. 2 is a schematic perspective view showing a main part of a battery module according to the first embodiment. [Figure 6] 3 is a schematic view of the cushioning member according to the first embodiment as viewed from the thickness direction. FIG. [Figure 7] 2 is a schematic plan view of a battery cell and a cushioning member in the first embodiment. FIG. [Figure 8] 8 is a diagram showing a schematic diagram of a state in which the battery cell has thermally expanded from the state shown in FIG. 7. FIG. [Figure 9] 13 is a schematic plan view of a battery cell and a cushioning member according to a second embodiment. FIG. [Figure 10] 10 is a diagram showing a schematic diagram of a state in which the battery cell has thermally expanded from the state shown in FIG. 9. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] First Embodiment A battery pack 10 and a battery module 11 according to a first embodiment will be described with reference to the drawings.

[0023] (Overall configuration of vehicle 100) Fig. 1 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. As shown in Fig. 1, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) in which the battery pack 10 is mounted under the floor. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle vertical direction, the front side in the vehicle longitudinal direction, and the left side in the vehicle width direction, respectively. When describing using the front-rear, left-right, up-down directions, they refer to the front-rear in the vehicle longitudinal direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0024] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are disposed on the vehicle front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are disposed on the vehicle rear side of the battery pack 10.

[0025] The direct current output from the battery pack 10 has its voltage adjusted by a DC / DC converter 102, and is then supplied to an electric compressor 104, a PTC heater 106, an inverter 112, etc. In addition, power is supplied to a motor 108 via the inverter 112, causing the rear wheels to rotate and causing the vehicle 100 to run.

[0026] A charging port 116 is provided on the right side at the rear of the vehicle 100, and by connecting a charging plug of an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the on-board charger 114.

[0027] The arrangement and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle in which the motor 108 is mounted at the rear of the vehicle, but the present invention is not limited to this. The vehicle may be a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, the vehicle may be equipped with an in-wheel motor on each wheel.

[0028] Here, the battery pack 10 is configured to include a plurality of battery modules 11. As an example in this embodiment, ten battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle front-rear direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle front-rear direction. In addition, each battery module 11 is electrically connected.

[0029] Fig. 2 is a schematic perspective view of the battery module 11. As shown in Fig. 2, the battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is formed of an aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die castings to both ends of an aluminum alloy extrusion material by laser welding or the like.

[0030] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, which will be described later, is connected to the connector 14. In addition, bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0031] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle up-down direction is, for example, 80 mm to 110 mm.

[0032] Fig. 3 is a plan view of the battery module 11 with the top cover removed. As shown in Fig. 3, a plurality of battery cells 20 are housed in an arranged state inside the battery module 11. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to one another.

[0033] A flexible printed circuit (FPC) 21 is disposed on the battery cells 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and a thermistor 23 is provided on each of both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cells 20, and is configured to be pressed towards the battery cells 20 by the upper lid of the battery module 11.

[0034] Fig. 4 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 4, the battery cell 20 is formed in a substantially rectangular plate shape, and houses an electrode body (not shown) inside. The electrode body is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22.

[0035] In this embodiment, as an example, the housing portion for the electrode body is formed by folding and pasting an embossed sheet-like laminate film 22. Note that, although both a single cup embossed structure in which embossing is performed at one place and a double cup embossed structure in which embossing is performed at two places can be adopted, the present embodiment adopts a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0036] The upper ends of the battery cells 20 at both ends in the longitudinal direction are bent to form corners. The upper end of the battery cells 20 is also bent, and a fixing tape 24 is wound around the upper end of the battery cells 20 along the longitudinal direction.

[0037] Here, terminals (tabs) 26 are provided at both longitudinal ends of the battery cell 20. In this embodiment, as an example, the terminals 26 are provided at positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to a bus bar (not shown) by laser welding or the like.

[0038] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, the length CW2 of the region in which the electrode body is housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm, 110 mm to 140 mm. The thickness of the battery cell 20 is 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, 9.0 mm to 11.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm, 50 mm to 60 mm, 60 mm to 70 mm.

[0039] (Cushioning members 32, 34) Fig. 5 is a schematic perspective view showing a main part of a battery module 11 in an embodiment. As shown in Fig. 5, 24 battery cells 20 are housed without gaps in a state aligned in the front-rear direction of the vehicle in a module case 30 serving as a housing constituting the battery module 11.

[0040] Furthermore, one or more cushioning materials are housed inside the module case 30. In the present embodiment, as an example, a total of three cushioning materials, that is, one cushioning member 32 and two cushioning members 34, are housed inside the module case 30.

[0041] The cushioning member 32 is disposed between adjacent battery cells 20 with the arrangement direction of the battery cells 20 (vehicle front-rear direction) as the thickness direction, and is formed from an elastically deformable thin plate-like member. In particular, the cushioning member 32 is disposed in the center portion of the module case 30 in the vehicle front-rear direction. In this embodiment, as an example, twelve battery cells 20 are disposed on the vehicle front side of the cushioning member 32, and twelve battery cells 20 are disposed on the vehicle rear side of the cushioning member 32. For this reason, the cushioning member 32 is disposed at a position that equally divides the arranged battery cells 20.

[0042] Fig. 6 is a schematic diagram of the cushioning member 32 in the embodiment as viewed from the thickness direction. Fig. 7 is a schematic plan view of the battery cell 20 and the cushioning members 32, 34 in the embodiment. As shown in Figs. 6 and 7, the cushioning member 32 in the embodiment is formed so that the thickness of the central portion 32A is thinner than that of the peripheral end portion 32B. In other words, the cushioning member 32 is formed so that the reaction force acting on the battery cell 20 is smaller at the central portion 32A than at the peripheral end portion 32B. Note that, for ease of explanation, Fig. 7 illustrates the longitudinal lengths of the battery cell 20, the cushioning member 32, and the cushioning member 34 as being shorter, which differs from the actual relationship between thickness and length. The same applies to Figs. 8 to 10 described below.

[0043] In the present embodiment, the buffer member 32 is formed, as an example, in such a shape that the region of the central portion 32A is formed in a substantially elliptical shape when viewed from the thickness direction, and the thickness gradually decreases toward the center. However, the present invention is not limited to this, and the region of the central portion 32A may be substantially rectangular or substantially elliptical when viewed from the thickness direction. In addition, the buffer member 32 is formed in such a shape that the outer shape is substantially rectangular when viewed from the thickness direction, but the present invention is not limited to this, and the buffer member 32 may be formed in a substantially elliptical shape with rounded corners.

[0044] Here, the central portion 32A of the buffer member 32 is the region between the imaginary lines L1 and L2 in Fig. 7. In the battery cell 20, the region between the imaginary lines L1 and L2 corresponds to an active material application region where an electrode active material is applied.

[0045] 5, the two cushioning members 34 are arranged between the battery cells 20 and the inner walls of the front and rear side walls 30A of the module case 30, with the arrangement direction of the battery cells 20 (the vehicle front-rear direction) as the thickness direction. For this reason, the battery cells 20 are in close contact with one surface of the cushioning member 34, and the side wall 30A is in close contact with the other surface of the cushioning member 34.

[0046] The cushioning member 34 has approximately the same outer shape as the cushioning member 32. That is, the cushioning member 34 of this embodiment is formed in an approximately rectangular shape when viewed in the thickness direction. Also, as shown in Fig. 7, the cushioning member 34 is formed so that the thickness of the central portion 34A is thinner than that of the peripheral end portion 34B. In other words, the cushioning member 34 is formed so that the reaction force acting on the battery cell 20 is smaller at the central portion 34A than at the peripheral end portion 34B.

[0047] The cushioning member 34 located at the front of the vehicle is formed so that a central portion 34A of the surface on the vehicle rear side, i.e., the surface adjacent to the battery cell 20, is recessed toward the front of the vehicle and gradually becomes thinner toward the center. In addition, the surface of the cushioning member 34 on the vehicle front side is formed in a substantially flat shape along the inner wall (not shown) of the module case 30.

[0048] On the other hand, the cushioning member 34 located at the rear of the vehicle has a shape that is symmetrical in the front-rear direction with respect to the cushioning member 34 located at the front of the vehicle. That is, the cushioning member 34 located at the rear of the vehicle has a central portion 34A of the surface on the front side of the vehicle, i.e., the surface adjacent to the battery cell 20, recessed toward the rear side of the vehicle, and is formed in a shape that gradually becomes thinner toward the center. In addition, the surface on the front side of the vehicle of the cushioning member 34 is formed in a substantially flat shape along the inner wall (not shown) of the module case 30. Note that in FIG. 7, for convenience of explanation, the difference in thickness between the central portion 32A and the peripheral end portion 32B of the cushioning member 32 and the difference in thickness between the central portion 34A and the peripheral end portion 34B of the cushioning member 34 are exaggerated. In reality, there is no gap, or there is almost no gap, between the central portion 32A of the cushioning member 32 and the battery cell 20. Similarly, in reality, there is no gap, or there is almost no gap, between the central portion 34A of the cushioning member 34 and the battery cell 20.

[0049] Fig. 8 is a schematic diagram showing a state in which the battery cell 20, the buffer member 32, and the buffer member 34 are housed in the module case 30 and the battery cell 20 has thermally expanded. As shown in Fig. 8, the battery cell 20 thermally expands due to repeated charging and discharging, etc. In particular, the active material application region of the battery cell 20 thermally expands, and the center of the battery cell 20 bulges outward.

[0050] Here, in this embodiment, because the thickness of the central portion 32A of the cushioning member 32 is thin, the central portion of the battery cell 20 fits into this thinner portion, making it possible for the reaction force acting from the cushioning member 32 to be approximately the same at the central portion and the peripheral edge portions. Similarly, because the thickness of the central portion 34A of the cushioning member 34 is thin, the central portion of the battery cell 20 fits into this thinner portion, making it possible for the reaction force acting from the cushioning member 34 to be approximately the same at the central portion and the peripheral edge portions.

[0051] (action) Next, the operation of the battery module 11 and the battery pack 10 according to this embodiment will be described.

[0052] In the battery module 11 according to this embodiment, a plurality of battery cells 20 are housed in an arranged state inside a module case 30. In addition, a buffer member 32 is disposed between adjacent battery cells 20, and a buffer member 34 is disposed between the battery cells 20 and the inner wall of the module case 30.

[0053] Here, the cushioning members 32 and 34 have their thickness direction aligned with the arrangement direction of the battery cells, and are formed so that the reaction force acting on the battery cell 20 is smaller at the central portions 32A, 34A than at the peripheral ends 32B, 34B of each of the cushioning members 32, 34. As a result, when the battery cell 20 thermally expands and the central portion of the battery cell 20 bulges, the reaction force acting on the battery cell 20 from the cushioning members 32, 34 can be made approximately uniform between the central portion and the peripheral ends, and the thermal expansion of the battery cell 20 can be absorbed by the cushioning members 32, 34.

[0054] In addition, because thermal expansion of the battery cells 20 places the greatest stress on the central portion of the battery module 11 in the front-to-rear direction, by locating the buffer member 32 in this central portion of the battery module 11, the thermal expansion of the battery cells 20 can be effectively absorbed by the entire battery module 11.

[0055] Furthermore, in this embodiment, by making the thickness of the central portions 32A, 34A of the cushioning members 32, 34 thinner than the peripheral ends 32B, 34B, the reaction force acting from the peripheral ends 32B, 34B of the cushioning members 32, 34 to the battery cell 20 can be made smaller than the reaction force acting from the peripheral ends 32B, 34B of the cushioning members 32, 34 to the battery cell 20.

[0056] Furthermore, in this embodiment, by arranging buffer members 34 between the inner walls of both side walls 30A of the module case 30 and the battery cells 20, the reaction force acting from the inner walls of the module case 30 to the battery cells 20 can be reduced.

[0057] <Second embodiment> Next, a battery module 50 according to a second embodiment will be described with reference to the drawings. Note that the same components as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0058] Fig. 9 is a schematic plan view of the battery cells and cushioning members in the second embodiment. As shown in Fig. 9, the battery module 50 of the present embodiment has the same structure as the first embodiment, except for the central thick cushioning member 52.

[0059] The central thick cushioning member 52 is disposed in the center of the battery module 50 in the arrangement direction of the battery cells 20, with the arrangement direction of the battery cells 20 being the thickness direction. The central thick cushioning member 52 is formed to have a substantially rectangular outer shape when viewed in the thickness direction.

[0060] Here, in the present embodiment, the central thick cushioning member 52 is formed so that the central portion 52A is thicker than the peripheral end portions 52B.

[0061] (action) Next, the operation of the battery module 50 according to this embodiment will be described.

[0062] Fig. 10 is a diagram that shows a state in which the battery cells 20 have thermally expanded from the state shown in Fig. 9. As shown in Fig. 10, in this embodiment, the thermal expansion of the battery cells 20 is absorbed by the cushioning members 34 that are arranged on both the front and rear sides of the battery module 50.

[0063] In addition, the central thick cushioning member 52 arranged in the central portion in the vehicle front-rear direction curves the central portion of the battery cell 20. This allows the terminals 26 extending from the ends of the battery cells 20 to be bent toward the center in the arrangement direction of the battery cells 20, thereby preventing stress from concentrating on the terminals 26.

[0064] That is, if only the terminals 26 were bent, stress would be concentrated at the base portions of the terminals 26, which could damage the terminals 26, but by curving the battery cells 20 themselves as in this embodiment, it is possible to prevent stress from being concentrated at the base portions of the terminals 26. Other functions are the same as in the first embodiment.

[0065] Although the battery pack 10 and the battery module 11 according to the present embodiment have been described above, the present invention is not limited thereto, and may be embodied in various forms without departing from the gist of the present invention. For example, in the first embodiment, as shown in Fig. 7, the cushioning members 32, 34 are gradually thinner from the peripheral ends 32B, 34B to the central parts 32A, 34A, but the present invention is not limited thereto. For example, the cushioning members 32, 34 may be shaped to have a stepped shape with a stepped thickness.

[0066] In addition, the cushioning members 32, 34 are formed so that the central portions 32A, 34A are thinner than the peripheral portions 32B, 34B, but the present invention is not limited to this. As another embodiment, a cushioning member formed so that the density of the central portion is lower than that of the peripheral portions may be used. For example, when the cushioning member is formed of a foamed resin, the amount of foaming may be controlled to form a cushioning member having a lower density at the central portion than that of the peripheral portions. By making the density of the central portion of the cushioning member lower than that of the peripheral portions, the reaction force acting from the central portion of the cushioning member to the battery cell can be made smaller than the reaction force acting from the peripheral portions of the cushioning member to the battery cell. As a result, as in the above embodiment, the reaction force acting from the cushioning member to the battery cell 20 during thermal expansion of the battery cell 20 can be made approximately uniform between the central portion and the peripheral portions, and the effect of absorbing the thermal expansion of the battery cell 20 by the cushioning member can be obtained.

[0067] Furthermore, materials having different elastic moduli may be used for the center and the peripheral edges of the cushioning member. Specifically, by using a material having a lower elastic modulus for the center of the cushioning member than for the peripheral edges, the reaction force acting from the center of the cushioning member to the battery cell can be made smaller than the reaction force acting from the peripheral edges of the cushioning member to the battery cell, as in the above embodiment.

[0068] Regarding the above embodiment, the following notes are disclosed.

[0069] (Appendix 1) A plurality of battery cells housed in an array inside a housing; a buffer member disposed at least one of between adjacent battery cells and between the battery cells and an inner wall of the housing, with the arrangement direction of the battery cells being the thickness direction, and formed so that a reaction force acting on the battery cells is smaller at a central portion than at a peripheral end portion; A battery module having (Appendix 2) 2. The battery module according to claim 1, wherein the buffer member is disposed at least in a central portion of the casing in a direction in which the battery cells are arranged. (Appendix 3) The battery module according to claim 1 or 2, wherein the cushioning member is formed so that a central portion is thinner than a peripheral portion. (Appendix 4) The battery module according to any one of claims 1 to 3, wherein the cushioning member is formed so that the density of the central portion is lower than that of the peripheral portion. (Appendix 5) The battery module according to any one of claims 1 to 4, wherein the buffer members are disposed at least between the battery cells and inner walls on both sides of the housing. (Appendix 6) The battery module described in Appendix 5, wherein a central thick cushioning member having a thickness greater at the center than at the peripheral ends is disposed in the central portion of the housing in the arrangement direction of the battery cells. (Appendix 7) A battery pack comprising a plurality of battery modules according to any one of claims 1 to 6. [Explanation of symbols]

[0070] 10 Battery pack 11,50 Battery module 20 Battery Cells 30 Module case (housing) 32,34 Cushioning material 32A,34A central part 32B,34B peripheral edge 52 Central thick cushioning member 52A Central part 52B Peripheral end

Claims

1. A plurality of battery cells housed in an array inside a housing; a buffer member disposed at least one of between adjacent battery cells and between the battery cells and an inner wall of the housing, with the arrangement direction of the battery cells being the thickness direction, and formed so that a reaction force acting on the battery cells is smaller at a central portion than at a peripheral end portion; A battery module having

2. The battery module according to claim 1 , wherein the buffer member is disposed at least in a central portion of the housing in a direction in which the battery cells are arranged.

3. The battery module according to claim 1 , wherein the cushioning member is formed so that a central portion is thinner than a peripheral portion.

4. The battery module according to claim 1 , wherein the cushioning member is formed so that the density of a central portion is lower than that of a peripheral portion.

5. The battery module according to claim 1 , wherein the buffer members are disposed at least between the battery cells and inner walls on both sides of the housing.

6. The battery module according to claim 5 , wherein a central thick cushioning member having a thickness greater at a central portion than at peripheral ends is disposed in a central portion of the casing in a direction in which the battery cells are arranged.

7. A battery pack comprising a plurality of battery modules according to any one of claims 1 to 6.

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