Battery module

Abstract

To provide a battery module which can suppress increase of manufacturing steps and cost and can suppress thermal expansions.SOLUTION: A battery module 11 includes: a long battery cell 20 formed by sealing an electrode body with a laminate film; and a case 13 for storing a battery cell group in which a plurality of battery cells 20 are arranged. The case 13 includes: a pair of shorter-side wall parts 13A extending along the direction of lamination of the battery cells 20; and a pair of longer-side wall parts 13B connecting the shorter-side wall parts 13A to each other. The longer-side wall parts 13B are formed not to be easily deformed in the thickness direction with respect to the shorter-side wall parts 13A.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Patent Document 1 discloses a battery module in which an electrode assembly is housed in a case. The outside of the electrode assembly is surrounded by a heat-shrinkable protective layer, thereby suppressing thermal expansion of the electrode assembly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2018 / 287184 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since a heat-shrinkable protective layer is formed, the number of manufacturing steps and costs increase compared to a structure in which a heat-shrinkable protective layer is not formed.

[0005] In consideration of the above, an object of the present invention is to provide a battery module capable of suppressing thermal expansion while suppressing increases in manufacturing steps and costs. [Means for solving the problem]

[0006] The battery module of claim 1 comprises an elongated battery cell formed by sealing an electrode body with a laminate film, and a case capable of accommodating a battery cell group in which a plurality of the battery cells are arranged, the case including a pair of short side wall portions extending along the stacking direction of the battery cells, and a pair of long side wall portions connecting the short side wall portions, the long side wall portions being formed in a shape that makes them less susceptible to deformation in the thickness direction relative to the short side wall portions.

[0007] In the battery module according to claim 1, the battery cells are formed by sealing the electrode body with a laminate film, and are long in shape. The case is capable of housing a battery cell group in which a plurality of battery cells are arranged. Here, the case is configured to include a pair of short side wall portions extending along the stacking direction of the battery cells, and a pair of long side wall portions connecting the short side wall portions, and the long side wall portions are formed in a shape that is difficult to deform in the plate thickness direction relative to the short side wall portions. As a result, when the battery cells thermally expand, a reaction force is applied from the long side wall portions of the case to the battery cells, thereby suppressing the thermal expansion of the battery cells. Also, since the long side wall portions of the case are shaped to be difficult to deform in the plate thickness direction to suppress the thermal expansion of the battery cells, a dedicated member such as a heat-shrinkable protective layer is not required.

[0008] A battery module according to a second aspect of the present invention is the battery module according to the first aspect, wherein the short side wall portions are formed in a straight line, and the long side wall portions are formed in a shape in which a central portion in a longitudinal direction is convex inward.

[0009] In the battery module according to claim 2, the longitudinal center portion of the long-side sidewall portion is convex inward. Since the longitudinal center portion of the battery cell is likely to expand during thermal expansion, by bringing the longitudinal center portion of the long-side sidewall portion into contact with the battery cell group, the thermal expansion of the battery cells can be effectively suppressed.

[0010] The battery module according to claim 3 is based on claim 2, and the longitudinal center portion of the long side wall portion is in contact with the battery cell group in an unloaded state.

[0011] In the battery module according to claim 3, since the long side wall portions are in contact with the battery cell group in an unloaded state, it is possible for the long side wall portions to apply a binding pressure to the battery cell group.

[0012] A battery module according to a fourth aspect of the present invention is the battery module according to the first aspect, wherein the long-side side wall portion is formed so that a central portion in a longitudinal direction is thicker than other portions.

[0013] In the battery module according to claim 4, the central portion in the longitudinal direction of the long side wall is thickened, and therefore has greater strength than other portions. This allows the battery module to effectively withstand the force from the battery cells when they thermally expand, while also reducing its weight compared to when the entire long side wall is made thick.

[0014] A battery module according to claim 5 is based on claim 1, wherein the connection portions of the long side wall portions and the short side wall portions are formed to be thicker than other portions.

[0015] In the battery module of claim 5, even if a load is input from the battery cell to the long side wall portion during thermal expansion and the load is concentrated at the connection portion between the long side wall portion and the short side wall portion, deformation can be suppressed because the connection portion between the long side wall portion and the short side wall portion is thicker than other portions. Effect of the Invention

[0016] As described above, the battery module according to the present invention can suppress thermal expansion while suppressing increases in manufacturing steps and costs. [Brief description of the drawings]

[0017] [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. 1 is a schematic perspective view of a battery module according to a first embodiment. [Diagram 3] 2 is a schematic diagram of a battery cell accommodated in the battery module according to the first embodiment, viewed from the thickness direction. FIG. [Figure 4] FIG. 2 is a plan view of the battery module according to the first embodiment with the top cover removed. [Diagram 5] FIG. 11 is a plan view of a battery module according to a second embodiment with a top cover removed. [Figure 6] FIG. 11 is a plan view of a battery module according to a third embodiment with its top cover removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] First Embodiment A battery module 11 according to a first embodiment will be described with reference to the drawings.

[0019] (Overall configuration of vehicle 100) Fig. 1 is a schematic plan view showing a main part of a vehicle 100 to which a battery module 11 according to this embodiment is applied. As shown in Fig. 1, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) with a battery pack 10 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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 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 castings to both ends of an extruded aluminum alloy material by laser welding or the like.

[0026] 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.

[0027] 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.

[0028] Fig. 3 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 3, the battery cell 20 is formed in a substantially rectangular plate shape, and houses a long electrode body 19 therein. The electrode body 19 is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22.

[0029] In this embodiment, as an example, an embossed sheet-like laminate film 22 is folded and bonded to form a housing portion for the electrode body 19. Although both a single cup embossed structure in which one portion is embossed and a double cup embossed structure in which two portions are embossed can be used, the present embodiment employs a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0030] 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.

[0031] 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.

[0032] 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 area in which the electrode body 19 is housed 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. For this reason, the battery cell 20 is formed in an elongated shape, and the direction of the lengths CW1 and CW2 is the longitudinal direction.

[0033] 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.

[0034] Fig. 4 is a plan view of the battery module 11 according to the first embodiment with the top cover removed. As shown in Fig. 4, a battery cell group in which a plurality of battery cells 20 are arranged is housed 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.

[0035] 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.

[0036] Furthermore, one or more buffer plates (not shown) are housed inside the battery module 11. For example, the buffer plate is an elastically deformable thin plate member, and is disposed between adjacent battery cells 20 with the arrangement direction of the battery cells 20 being the thickness direction. In this embodiment, as an example, buffer materials are disposed at both ends in the longitudinal direction of the battery module 11 and at the longitudinal center portion, but the buffer materials do not necessarily have to be disposed.

[0037] Here, the case 13 is configured to include a pair of short side wall portions 13A extending along the stacking direction of the battery cells 20, and a pair of long side wall portions 13B connecting the short side wall portions 13A, and the long side wall portions 13B are formed in a shape that makes them less susceptible to deformation in the thickness direction relative to the short side wall portions 13A.

[0038] Specifically, the pair of short side wall portions 13A constituting the case 13 are each formed in a substantially linear shape in a plan view. On the other hand, the pair of long side wall portions 13B are each formed in a shape in which the longitudinal center portion is convex inward. In other words, the pair of long side wall portions 13B are each recessed in the opposing direction.

[0039] Furthermore, in this embodiment, the longitudinal center portion of the long side wall portion 13B is in contact with the battery cell 20 (battery cell group) in an unloaded state, and the battery cell group is restrained from both sides by the long side wall portion 13B.

[0040] (action) Next, the operation of the battery module 11 according to this embodiment will be described.

[0041] In the battery module 11 according to the present embodiment, the battery cells 20 are formed by sealing the electrode body 19 with a laminate film 22, and are long in shape. The case 13 is capable of housing a battery cell group in which a plurality of battery cells 20 are arranged. Here, the long side wall portion 13B of the case 13 is formed in a shape that is difficult to deform in the plate thickness direction relative to the short side wall portion 13A. As a result, when the battery cell 20 thermally expands, a reaction force is applied from the long side wall portion 13B of the case 13 to the battery cell 20, thereby suppressing the thermal expansion of the battery cell 20. In addition, since the long side wall portion 13B of the case 13 is shaped to be difficult to deform in the plate thickness direction to suppress the thermal expansion of the battery cell 20, a dedicated member such as a heat-shrinkable protective layer is not required. That is, according to the battery module 11 of the present embodiment, it is possible to suppress the thermal expansion while suppressing an increase in the manufacturing man-hours and costs.

[0042] In this embodiment, the longitudinal center portion of the long-side sidewall portion 13B is convex inward. Here, since the longitudinal center portion of the battery cell 20 is likely to expand during thermal expansion, by bringing the longitudinal center portion of the long-side sidewall portion 13B into contact with the battery cell group, the thermal expansion of the battery cell 20 can be effectively suppressed.

[0043] In particular, in this embodiment, since the long side wall portions 13B are in contact with the battery cells 20 (battery cell group) in the no-load state, the long side wall portions 13B can apply a restraining pressure to the battery cell group.

[0044] <Second embodiment> Next, a battery module 50 according to a second embodiment will be described with reference to Fig. 5. 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.

[0045] Fig. 5 is a plan view of the battery module 50 of this embodiment with the top cover removed. As shown in Fig. 5, in this embodiment, the long-side side wall portion 13B is formed so that the central portion in the longitudinal direction is thicker than other portions.

[0046] Specifically, the case 13 of the battery module 50 of this embodiment is configured to include a pair of short side wall portions 13A formed in a substantially straight line when viewed in a plane, and a pair of long side wall portions 13B formed in a substantially straight line when viewed in a plane.

[0047] Here, each long side wall portion 13B has a thick portion 52 formed in the longitudinal center portion. The thick portion 52 is formed to be thicker than other portions. Therefore, the long side wall portion 13B is formed so that the longitudinal center portion is shaped to be convex inward. Furthermore, the thick portion 52 is in contact with the battery cell 20 in an unloaded state.

[0048] (action) Next, the operation of the battery module 50 according to this embodiment will be described.

[0049] In this embodiment, the thick-walled portion 52 in the longitudinal center of the long-side sidewall portion 13B is thick, and therefore has greater strength than other portions. This allows the weight to be reduced compared to when the entire long-side sidewall portion 13B is made thick, while still adequately receiving the force from the battery cells 20 when the battery cells 20 thermally expand. Other functions are the same as in the first embodiment.

[0050] <Third embodiment> Next, a battery module 60 according to a third embodiment will be described with reference to Fig. 6. Note that the same components as those in the first embodiment are given the same reference numerals and the description thereof will be omitted as appropriate.

[0051] Fig. 6 is a plan view of the battery module 60 in this embodiment with the top cover removed. As shown in Fig. 6, in this embodiment, the connection portion of the long side wall portion 13B with the short side wall portion 13A is formed thicker than other portions.

[0052] Specifically, the case 13 of the battery module 60 of this embodiment is configured to include a pair of short side wall portions 13A formed in an approximately straight line when viewed in a plane, and a pair of long side wall portions 13B connecting the short side wall portions 13A.

[0053] Here, the outer surface of the long side wall portion 13B is recessed in the stacking direction of the battery cells 20. The inner surface of the long side wall portion 13B is approximately parallel to the battery cells 20. For this reason, the long side wall portion 13B is formed in a shape that increases in thickness from the longitudinal center toward the ends, and the connection portion of the long side wall portion 13B with the short side side wall portion 13A is formed to be the thickest.

[0054] (action) Next, the operation of the battery module 60 according to this embodiment will be described.

[0055] In this embodiment, even if a load is input from the battery cell 20 to the long side wall 13B during thermal expansion of the battery cell 20 and the load is concentrated at the connection portion between the long side wall 13B and the short side wall 13A, the connection portion between the long side wall 13B and the short side wall 13A is thicker than other portions, so deformation can be suppressed. Other functions are the same as in the first embodiment.

[0056] Although the battery modules 11, 50, and 60 according to the embodiments have been described above, the present invention is not limited thereto and may be embodied in various forms without departing from the spirit and scope of the present invention. For example, in the above embodiment, the longitudinal center portion of the long-side side wall portion 13B contacts the battery cell 20 in an unloaded state, but the present invention is not limited thereto and may be configured such that the long-side side wall portion does not contact the battery cell.

[0057] In the first embodiment, the longitudinal center of the long-side side wall 13B is formed in a shape that is convex inward, but this is not limited thereto, and other shapes may be used. For example, the portion of the long-side side wall offset toward the end from the longitudinal center may be formed in a shape that is convex inward.

[0058] Regarding the above embodiment, the following notes are disclosed.

[0059] (Appendix 1) a long battery cell formed by sealing the electrode body with a laminate film; a case capable of accommodating a battery cell group in which a plurality of the battery cells are arranged; having the case is configured to include a pair of short side wall portions extending along a stacking direction of the battery cells and a pair of long side wall portions connecting the short side wall portions, The long side wall portion is formed in a shape that is less likely to deform in a plate thickness direction relative to the short side wall portion. Battery module. (Appendix 2) The short side wall portion is formed in a straight line, The battery module according to claim 1, wherein the long-side side wall portion is formed so that a longitudinal central portion thereof is convex inwardly. (Appendix 3) 3. The battery module according to claim 1, wherein a longitudinal center portion of the long-side side wall portion is in contact with the battery cell group in an unloaded state. (Appendix 4) 4. The battery module according to claim 1, wherein the long-side side wall portion has a central portion in a longitudinal direction formed to be thicker than other portions. (Appendix 5) The battery module according to claim 1, wherein a connection portion of the long side wall portion to the short side wall portion is formed to be thicker than other portions. [Explanation of symbols]

[0060] 11 Battery module 13 cases 13A Short side wall 13B Long side wall 19 Electrode body 20 Battery Cells 22 Laminating film 50 Battery Module 60 Battery Module

Claims

1. a long battery cell formed by sealing the electrode body with a laminate film; a case capable of accommodating a battery cell group in which a plurality of the battery cells are arranged; having the case is configured to include a pair of short side wall portions extending along a stacking direction of the battery cells and a pair of long side wall portions connecting the short side wall portions, The long side wall portion is formed in a shape that is less likely to deform in a plate thickness direction relative to the short side wall portion. Battery module.

2. The short side wall portion is formed in a straight line, The battery module according to claim 1 , wherein the long-side sidewall portion has a longitudinal center portion formed into an inwardly convex shape.

3. The battery module according to claim 2 , wherein a longitudinal center portion of each of the long side walls is in contact with the battery cell group in an unloaded state.

4. The battery module according to claim 1 , wherein a longitudinal center portion of the long side wall portion is formed to be thicker than other portions.

5. The battery module according to claim 1 , wherein a connection portion of said long side wall portion and said short side wall portion is formed to be thicker than other portions.

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