Battery module

Abstract

To provide a battery module which can maintain an excellent performance of a battery in a structure using a long battery cell.SOLUTION: The battery module includes: a battery cell 20 formed by sealing a long electrode body with a laminate film; and a case for storing the arrangement of battery cells 20. Battery cells 20 adjacent to each other are attached together by an adhesive 50 and there is a difference in the amount of the adhesive 50 between the center part and the edge part in the longer direction of the battery cell 20.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a battery module.

Background Art

[0002] Patent Document 1 discloses a battery module in which an electrode assembly is housed in a case. Further, by surrounding the outside of the electrode assembly with a heat-shrinkable protective layer, a structure is provided that suppresses thermal expansion of the electrode assembly.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to improve the volume efficiency of the battery, it has been considered to use a longer battery cell. However, a long battery cell is more likely to warp due to charge and discharge. For this reason, even in a structure surrounded by a heat-shrinkable protective layer like the battery module described in Patent Document 1 above, when the battery cell warps, the surface pressure cannot be maintained constant, and the performance of the battery may not be maintained well.

[0005] In consideration of the above facts, an object of the present invention is to obtain a battery module capable of maintaining good battery performance in a structure using a long battery cell.

Means for Solving the Problems

[0006] The battery module according to claim 1 has a battery cell formed by sealing a long electrode body with a laminate film, and a case capable of accommodating a plurality of the battery cells arranged in a state, and adjacent battery cells are adhered by an adhesive, and the amount of the adhesive is different between the central portion and the end portion in the longitudinal direction of the battery cell.

[0007] In the battery module according to claim 1, the battery cell is formed by sealing a long electrode body with a laminate film, and is accommodated in a case in a state where a plurality of battery cells are arranged. Here, since the battery cells are adhered by an adhesive, it is possible to suppress the occurrence of a gap between adjacent battery cells due to warping of the battery cell.

[0008] Further, the amount of the adhesive is different between the central portion and the end portion in the longitudinal direction of the battery cell. Thereby, even when the battery cell is warped, it is possible to suppress variations in surface pressure between the central portion and the end portion of the battery cell. Here, the "central portion" refers to a predetermined range including the center in the longitudinal direction of the battery cell, for example, the central region when the battery cell is trisected in the longitudinal direction. Also, the "end portion" widely includes the region excluding the central portion, for example, the region excluding the central region when the battery cell is trisected in the longitudinal direction.

[0009] The battery module according to claim 2 is, in claim 1, the amount of the adhesive is larger in the end portion than in the central portion.

[0010] In the battery module according to claim 2, even when the end portions of adjacent battery cells are warped in a direction of separation, by increasing the amount of the adhesive in the end portion, it is possible to suppress variations in surface pressure between the central portion and the end portion of the battery cell.

[0011] The battery module according to claim 3 is, in claim 2, the thickness of the adhesive is thicker in the end portion than in the central portion.

[0012] In the battery module according to claim 3, it is possible to suppress variations in the surface pressure of the battery cells by simply changing the thickness of the adhesive material.

[0013] The battery module according to claim 4 is, in claim 1, characterized in that the amount of the adhesive material is larger in the central portion than in the end portion.

[0014] In the battery module according to claim 4, even when the central portions of adjacent battery cells are warped in a direction away from each other, by increasing the amount of the adhesive material in the central portion, it is possible to suppress variations in the surface pressure between the central portion and the end portion of the battery cells.

[0015] The battery module according to claim 5 is, in claim 4, characterized in that the thickness of the adhesive material is larger in the central portion than in the end portion.

[0016] In the battery module according to claim 5, it is possible to suppress variations in the surface pressure of the battery cells by simply changing the thickness of the adhesive material.

[0017] The battery module according to claim 6 is, in any one of claims 1 to 5, characterized in that the battery cell and the case are adhered to each other via an adhesive material.

[0018] In the battery module according to claim 6, by adhering the battery cell and the case with the adhesive material, it is possible to suppress, with a simple structure, variations in the restraining force acting from the case to the battery cell.

[0019] The battery module according to claim 7 is, in claim 6, characterized in that in the case, recesses are formed in the inner wall that is adhered to the battery cell via the adhesive material.

[0020] In the battery module according to claim 7, when inserting the battery cell into the case, by allowing the adhesive material between the battery cell and the case to enter the recesses, it is possible to suppress the accumulation of the adhesive material at the corners of the case.

[0021] The battery module according to claim 8, in any one of claims 1 to 5, the case is provided with a pressing member capable of pressing the battery cells in the array direction.

[0022] In the battery module according to claim 8, by pressing the battery cells in the array direction by the pressing member, it is possible to suppress, with a simple structure, a change in the restraining force acting from the case to the battery cells.

[0023] The battery module according to claim 9, in claim 8, the pressing member includes a leaf spring attached to the inner wall of the case and capable of applying a biasing force to the battery cells.

[0024] In the battery module according to claim 9, by simply changing the spring constant of the leaf spring, the restraining force acting from the case to the battery cells can be changed.

[0025] The battery module according to claim 10, in claim 8, the pressing member includes a screw that can be screwed into a screw hole penetrating the wall surface of the case.

[0026] In the battery module according to claim 10, the restraining force of the battery cells can be changed by the tightening degree of the screw screwed into the screw hole.

Advantages of the Invention

[0027] As described above, according to the battery module of the present invention, in a structure using long battery cells, the performance of the battery can be maintained well.

Brief Description of the Drawings

[0028]

Figure 1

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Figure 11

Best Mode for Carrying Out the Invention

[0029] <First Embodiment> The battery module 11 according to the first embodiment will be described with reference to the drawings.

[0030] (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 the present embodiment is applied. As shown in FIG. 1, the vehicle 100 is a battery electric vehicle (BEV) with the battery pack 10 mounted under the floor. In addition, the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle up-down direction, the front side in the vehicle front-rear direction, and the left side in the vehicle width direction, respectively. When explaining using the front-rear, left-right, and up-down directions of the vehicle, unless otherwise specified, the front and rear in the vehicle front-rear direction, the left and right in the vehicle width direction, and the up and down in the vehicle up-down direction are shown.

[0031] 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 arranged on the front side of the vehicle with respect to the battery pack 10. Also, on the rear side of the vehicle with respect to the battery pack 10, a motor 108, a gearbox 110, an inverter 112, and a charger 114 are arranged.

[0032] The direct current output from the battery pack 10 is supplied to the electric compressor 104, the PTC heater 106, the inverter 112, etc. after the voltage is adjusted by the DC / DC converter 102. Also, by supplying power to the motor 108 via the inverter 112, the rear wheels rotate to make the vehicle 100 run.

[0033] A charging port 116 is provided on the right side at the rear of the vehicle 100. By connecting a charging plug of an external charging facility (not shown) from the charging port 116, power can be stored in the battery pack 10 via the in-vehicle charger 114.

[0034] Note that the arrangement and structure of each component constituting the vehicle 100 are not limited to the above-described configuration. For example, it may be applied to a hybrid vehicle (HV) equipped with an engine or a plug-in hybrid electric vehicle (PHEV). Also, in this embodiment, the vehicle is a rear-wheel drive vehicle with the motor 108 mounted at the rear of the vehicle, but it is not limited to this. It may be a front-wheel drive vehicle with the motor 108 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, a vehicle equipped with in-wheel motors on each wheel may also be used.

[0035] Here, the battery pack 10 is configured to include a plurality of battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the vehicle front-rear direction on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the vehicle front-rear direction on the left side of the vehicle 100. Also, each of the battery modules 11 is electrically connected.

[0036] 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. Also, the case 13 of the battery module 11 is formed of an aluminum alloy. For example, the case 13 of the battery module 11 is formed by joining aluminum die casts to both ends of an extruded material of an aluminum alloy by laser welding or the like.

[0037] At both ends in the vehicle width direction of the battery module 11, a pair of voltage terminals 12 and a connector 14 are provided respectively. A flexible printed circuit board 21 described later is connected to the connector 14. Also, bus bars (not shown) are welded to both ends in the vehicle width direction of the battery module 11.

[0038] The length MW in the vehicle width direction of the battery module 11 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 vertical direction is, for example, 80 mm to 110 mm.

[0039] FIG. 3 is a plan view of the battery module 11 with the upper lid removed. As shown in FIG. 3, inside the battery module 11, a plurality of battery cells 20 are accommodated in an arranged state. In this embodiment, as an example, 24 battery cells 20 are arranged in the vehicle front-rear direction and adhered to each other.

[0040] On top of the battery cell 20, a flexible printed circuit (FPC) 21 is disposed. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit 21, respectively. The thermistor 23 is not adhered to the battery cell 20 and is configured to be pressed toward the battery cell 20 side by the upper lid of the battery module 11.

[0041] Also, inside the battery module 11, one or more cushioning materials (not shown) are accommodated. For example, the cushioning material is a thin plate-like member that can be elastically deformed and is disposed between adjacent battery cells 20 with the arrangement direction of the battery cells 20 as the thickness direction. In this embodiment, as an example, cushioning materials are disposed at both longitudinal ends and the central portion in the longitudinal direction of the battery module 11, respectively.

[0042] FIG. 4 is a schematic view of the battery cell 20 accommodated in the battery module 11 as viewed from the thickness direction. As shown in FIG. 4, the battery cell 20 is formed in a substantially rectangular plate shape, and a long electrode body 19 is accommodated therein. The electrode body 19 is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed by a laminate film 22.

[0043] In this embodiment, as an example, the accommodating portion of the electrode body 19 is formed by folding and bonding an embossed sheet-like laminate film 22. Note that both a single cup embossing structure with one embossing and a double cup embossing structure with two embossings can be adopted, but in this embodiment, a single cup embossing structure with a drawing depth of about 8 mm to 10 mm is used.

[0044] The upper ends at both longitudinal ends of the battery cell 20 are bent, and the corners form the outer shape. Also, the upper end portion of the battery cell 20 is bent, and a fixing tape 24 is wound along the longitudinal direction on the upper end portion of the battery cell 20.

[0045] Here, terminals (tabs) 26 are provided at both longitudinal ends of the battery cell 20. In this embodiment, as an example, the terminal 26 is provided at a position offset downward from the center in the vertical direction of the battery cell 20. The terminal 26 is joined to a bus bar (not shown) by laser welding or the like.

[0046] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, the length CW2 of the region in which the electrode body 19 is accommodated is, for example, 500 mm to 520 mm, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm. Therefore, the battery cell 20 is formed in a long shape, and the directions of the lengths CW1 and CW2 are the longitudinal directions.

[0047] Also, the thickness of the battery cell 20 is 7.0 mm to 9.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm. In the following description, the central region when the battery cell 20 is trisected in the longitudinal direction is defined as the central portion 20A, and the regions on both sides with respect to the central portion 20A are defined as the end portions 20B.

[0048] FIG. 5 is an enlarged plan view of the main part showing an enlarged view of the central portion 20A of the battery cell 20 constituting the battery module 11 in this embodiment. As shown in FIG. 5, an adhesive 50 is provided between adjacent battery cells 20, and the adjacent battery cells 20 are adhered to each other by this adhesive 50. The type of the adhesive 50 is not particularly limited, and for example, an acrylic resin adhesive, a urethane resin adhesive, an epoxy resin adhesive, a silicone resin adhesive, or the like may be used.

[0049] On the one hand, FIG. 6 is an enlarged plan view of a main part showing an end portion 20B of the battery cell 20 in the present embodiment. As shown in FIG. 6, also in the end portion 20B, an adhesive 50 is provided between adjacent battery cells 20, and the adjacent battery cells 20 are adhered to each other by this adhesive 50. Here, in the present embodiment, the amount of the adhesive 50 is different between the central portion 20A and the end portion 20B in the longitudinal direction of the battery cell 20. Specifically, in the present embodiment, the thickness of the adhesive 50 is formed thicker in the end portion 20B than in the central portion 20A of the battery cell 20. In other words, the amount of the adhesive 50 is larger in the end portion 20B than in the central portion 20A of the battery cell 20.

[0050] Note that "the end portion 20B of the battery cell 20 has a thicker adhesive 50 than the central portion 20A" means, for example, that the average thickness of the adhesive 50 in the end portion 20B of the battery cell 20 is thicker than the average thickness of the adhesive 50 in the central portion 20A. Also, even if the thicknesses of the central portion 20A and the end portion 20B are substantially the same, when the amount of the adhesive 50 provided in the entire end portion 20B is larger than the amount of the adhesive 50 provided in the entire central portion 20A, it is said that "the amount of the adhesive 50 is larger in the end portion 20B than in the central portion 20A of the battery cell 20".

[0051] FIG. 7 is an enlarged plan view of a main part showing an enlarged view of a portion between the case 13 and the battery cell 20 in the battery module 11 in the present embodiment. As shown in this FIG. 7, an adhesive 50 is provided between the battery cell 20 disposed at the outermost end portion and the case 13, and the battery cell 20 and the case 13 are adhered via the adhesive 50. In the present embodiment, the adhesive 50 for adhering the battery cell 20 and the case 13 and the adhesive 50 for adhering the battery cells 20 to each other are the same adhesive, but the present invention is not limited to this, and different adhesives may be used. Note that in FIG. 7, for convenience of explanation, the thickness of the adhesive 50 is exaggeratedly drawn and is different from the actual thickness.

[0052] FIG. 8 is a schematic cross-sectional plan view showing a state in the middle of inserting the battery cell 20 into the case 13 of the battery module 11 in the present embodiment. Note that, in FIG. 8, it is illustrated in a state where the ceiling portion of the case 13 is removed, but actually the case 13 is formed in a cylindrical shape including the ceiling portion. Further, in FIGS. 8, 9, and 10, for convenience of explanation, a plurality of battery cells 20 in which 24 battery cells 20 are arranged in the vehicle front-rear direction and adhered to each other are depicted as one battery cell group 25.

[0053] As shown in FIG. 8, a recess 13A is formed in the inner wall of the case 13. The inner wall in which the recess 13A is formed is the inner wall to which the battery cell 20 and the case 13 are adhered via the adhesive 50.

[0054] Here, at the time of manufacturing the battery module 11, the battery cell group 25 is inserted into the case 13 in a state where the adhesive 50 is applied to at least one of the battery cell group 25 and the inner wall of the case 13. At this time, a part of the adhesive 50 between the battery cell group 25 and the case 13 adheres to the end portion of the battery cell group 25.

[0055] As shown in FIG. 9, in a state where the insertion of the battery cell group 25 into the case 13 is completed, an excess adhesive 50 enters the recess 13A, so that the amount of the adhesive 50 between the case 13 and the battery cell group 25 becomes substantially uniform.

[0056] (Operation) Next, the operation of the battery module 11 according to the present embodiment will be described.

[0057] In the battery module 11 according to the present embodiment, the battery cell 20 is formed by sealing a long electrode body 19 with a laminate film 22, and is accommodated in the case 13 in a state where a plurality of battery cells 20 are arranged. Here, as shown in FIGS. 5 and 6, since the battery cells 20 are adhered to each other by the adhesive 50, it is possible to suppress the occurrence of a gap between adjacent battery cells 20 due to warping or the like of the battery cells 20.

[0058] Further, the amount of the adhesive 50 is different between the central portion 20A and the end portion 20B in the longitudinal direction of the battery cell 20. Thereby, even when the battery cell 20 is warped, it is possible to suppress variations in the surface pressure between the central portion 20A and the end portion 20B of the battery cell 20. As a result, in the structure using the long battery cell 20, the performance of the battery can be maintained well.

[0059] In particular, in the present embodiment, the amount of the adhesive 50 is larger and the thickness is thicker in the end portion 20B than in the central portion 20A of the battery cell 20. Thereby, even when the end portions of the adjacent battery cells 20 are warped in the direction of separation, by increasing the amount of the adhesive 50 in the end portion 20B, it is possible to suppress variations in the surface pressure between the central portion 20A and the end portion 20B of the battery cell 20.

[0060] Also, in the present embodiment, as shown in FIG. 7, by adhering the battery cell 20 and the case 13 with the adhesive 50, it is possible to suppress, with a simple structure, a change in the restraining force acting from the case 13 on the battery cell 20.

[0061] Furthermore, in the present embodiment, as shown in FIGS. 8 and 9, when the battery cell group 25 is inserted into the case 13, the adhesive 50 between the battery cell group 25 and the case 13 enters the recess 13A formed in the case 13, thereby suppressing the accumulation of the adhesive 50 at the corners of the case 13. Thereby, it is possible to effectively suppress the insertion of the battery cell group 25 from being inhibited by the adhesive 50.

[0062] <Second Embodiment> Next, the battery module 60 according to the second embodiment will be described with reference to FIG. 10. Note that the same reference numerals are given to the components having the same configuration as those in the first embodiment, and the description will be omitted as appropriate.

[0063] FIG. 10 is a schematic cross-sectional plan view showing a case 62 of the battery module 60 in the second embodiment. As shown in FIG. 10, the case 62 according to the present embodiment is different in that the recess 13A is not formed as compared with the first embodiment. Further, the case 62 has substantially the same size as the case 13 of the first embodiment.

[0064] Here, in the present embodiment, the case 62 is provided with a leaf spring 64 as a pressing member capable of pressing the battery cell group in the arrangement direction. The leaf spring 64 is attached to the inner wall of the case 62 and is configured to be able to apply a biasing force to the battery cell group.

[0065] Specifically, the leaf spring 64 is attached to the opposing wall surfaces in the case 62 and bulges in the opposing directions. For this reason, in a state where the battery cell group is inserted into the case 62, the battery cell group is pressed by the leaf spring 64 from both sides.

[0066] (Operation) Next, the operation of the battery module 60 according to the present embodiment will be described.

[0067] In the present embodiment, by pressing the battery cell group with the leaf spring 64, it is possible to suppress, with a simple structure, a change in the restraining force acting on the battery cells from the case 62. In particular, by simply changing the spring constant of the leaf spring 64, the restraining force acting on the battery cells from the case 62 can be changed.

[0068] Further, in the present embodiment, it is possible to suppress the movement of the battery cell group within the case 62 without interposing an adhesive between the case 62 and the battery cell group. Other operations are the same as those in the first embodiment.

[0069] <Third Embodiment> Next, the battery module 70 according to the third embodiment will be described with reference to FIG. 11. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0070] FIG. 11 is a schematic cross-sectional plan view showing the case 72 of the battery module 70 in the third embodiment. As shown in FIG. 11, the case 72 according to the present embodiment is different from the case 13 of the first embodiment in that the recess 13A is not formed. Further, the case 72 has substantially the same size as the case 13 of the first embodiment.

[0071] Here, in the present embodiment, a plurality of screw holes 72A are formed in one side wall of the case 72. As an example in the present embodiment, three screw holes 72A are formed. For example, the three screw holes 72A are formed at equal intervals.

[0072] Each screw hole 72A is formed so as to penetrate the side wall of the case 72. Further, a screw 74 as a pressing member is screwed into each screw hole 72A. The screw 74 is a so-called thumb screw without a head, and is configured to be able to press the battery cell group 25 inside the case 72 toward the wall surface side facing it by screwing it into the screw hole 72A.

[0073] (Operation) Next, the operation of the battery module 60 according to the present embodiment will be described.

[0074] In the present embodiment, the restraining force of the battery cell 20 can be changed by the tightening degree of the screw 74 screwed into the screw hole 72A. Other operations are the same as those in the first embodiment.

[0075] Although the battery modules 11, 60, and 70 according to the embodiments have been described above, the present invention is not limited thereto, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention. For example, in the first embodiment, as shown in FIGS. 5 and 6, the thickness of the adhesive 50 is formed thicker at the end portion 20B than at the central portion 20A of the battery cell 20. However, the present invention is not limited thereto, and the thickness of the adhesive 50 may be formed thicker at the central portion 20A than at the end portion 20B. In this case, even when the central portions 20A of adjacent battery cells 20 are warped in a direction away from each other, by increasing the amount of the adhesive at the central portion 20A, it is possible to suppress variations in surface pressure between the central portion 20A and the end portion 20B of the battery cell 20.

[0076] Further, the adhesive 50 may not be provided over the entire area of the battery cell 20. That is, there may be an area where the adhesive 50 is not provided.

[0077] Furthermore, in the first embodiment, the adhesive 50 is provided between the case 72 and the battery cell group 25. However, the present invention is not limited thereto, and the adhesive 50 may not be provided. For example, when there is no gap between the case 72 and the battery cell group 25, variations in surface pressure can be suppressed without bonding with the adhesive 50.

[0078] Regarding the above embodiments, the following supplementary notes are disclosed.

[0079] (Supplementary Note 1) A battery cell formed by sealing a long electrode body with a laminate film, A case capable of accommodating a plurality of the battery cells arranged in a state, having Adjacent battery cells are adhered to each other by an adhesive, The amount of the adhesive is different between the central portion and the end portion in the longitudinal direction of the battery cell, A battery module. (Supplementary Note 2) The battery module according to Supplementary Note 1, wherein the amount of the adhesive is larger at the end portion than at the central portion. (Supplementary Note 3) The battery module according to Supplementary Note 1 or 2, wherein the thickness of the adhesive is greater at the end portion than at the central portion. (Supplementary Note 4) The battery module according to Supplementary Note 1, wherein the amount of the adhesive is greater at the central portion than at the end portion. (Supplementary Note 5) The battery module according to Supplementary Note 1 or 4, wherein the thickness of the adhesive is greater at the central portion than at the end portion. (Supplementary Note 6) The battery module according to any one of Supplementary Notes 1 to 5, wherein the battery cell and the case are adhered via an adhesive. (Supplementary Note 7) The battery module according to Supplementary Note 6, wherein in the case, recesses are formed on the inner wall that is adhered to the battery cell via the adhesive. (Supplementary Note 8) The battery module according to any one of Supplementary Notes 1 to 5, wherein the case is provided with a pressing member capable of pressing the battery cells in the arrangement direction. (Supplementary Note 9) The battery module according to Supplementary Note 8, wherein the pressing member includes a leaf spring attached to the inner wall of the case and capable of applying a biasing force to the battery cells. (Supplementary Note 10) The battery module according to Supplementary Note 8, wherein the pressing member includes a screw that can be screwed into a screw hole penetrating the wall surface of the case.

Explanation of Reference Numerals

[0080] 11 Battery module 13 Case 13A Recess 19 Electrode body 20 Battery cell 20A Central portion 20B End portion 22 Laminate film 50 Adhesive 60 Battery module 62 Case 64 Leaf spring (pressing member) 70 Battery module 72 Case 72A Screw hole 74 Screw

Claims

1. a battery cell formed by sealing a long electrode body with a laminate film; a case capable of housing a plurality of the battery cells in an arranged state; having Adjacent battery cells are bonded to each other with an adhesive, The amount of the adhesive is different between a central portion and an end portion in the longitudinal direction of the battery cell. Battery module.

2. The battery module according to claim 1 , wherein the amount of the adhesive is greater at the end portions than at the central portion.

3. The battery module according to claim 2 , wherein the adhesive is thicker at the end portions than at the central portion.

4. The battery module according to claim 1 , wherein the amount of the adhesive is greater in the central portion than in the end portions.

5. The battery module according to claim 4 , wherein the adhesive is thicker in the central portion than in the end portions.

6. The battery module according to claim 1 , wherein the battery cells and the case are bonded together via an adhesive.

7. The battery module according to claim 6 , wherein a recess is formed in an inner wall of the case that is bonded to the battery cell via the adhesive.

8. 6. The battery module according to claim 1, wherein the case is provided with a pressing member capable of pressing the battery cells in an arrangement direction.

9. 9. The battery module according to claim 8, wherein the pressing member includes a leaf spring attached to an inner wall of the case and capable of applying a biasing force to the battery cells.

10. The battery module according to claim 8 , wherein the pressing member includes a screw that can be screwed into a screw hole that penetrates a wall surface of the case.

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