Laminate film, battery cell, and battery module

Abstract

To provide a laminate film, a battery cell, and a battery module that ensures loading performance while suppressing thermal expansion in a laminate film that houses an electrode body.SOLUTION: A laminate film 20 is a laminate film 22 that has an accommodation portion 32 that accommodates an electrode body 30 and seals the electrode body 30 in an accommodated state, and an uneven portion is formed on at least a part of the side wall portion 32B that faces the peripheral end surface of the electrode body 30 in the accommodation portion 32.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a laminate film, a battery cell, and a battery module. [Background technology]

[0002] Patent Document 1 discloses a sheet material type battery (battery cell) constructed by wrapping an electrode body in a sheet material (laminate film). In the sheet material type battery described in Patent Document 1, the electrode body is sandwiched between uneven plate materials, and the uneven plate materials are covered with a sheet material. This makes the surface of the sheet material type battery uneven, ensuring heat dissipation characteristics. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-49054 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the sheet-type battery described in Patent Document 1, both sides are formed with projections and recesses, so there is room for improvement in terms of improving the loading capacity when multiple batteries are housed in a case to form a module.

[0005] In consideration of the above, an object of the present invention is to provide a laminate film, a battery cell, and a battery module that ensures stackability while suppressing thermal expansion in a laminate film that houses an electrode assembly. [Means for solving the problem]

[0006] The laminate film of claim 1 is a laminate film that has an accommodation section that accommodates an electrode body and seals the electrode body in a accommodated state, and an uneven portion is formed on at least a part of the side wall portion that faces the peripheral end face of the electrode body in the accommodation section.

[0007] The laminate film according to claim 1 includes a housing portion for housing the electrode body, and the housing portion includes a side wall portion facing the peripheral end face of the electrode body. Since an uneven portion is formed on at least a part of the side wall portion, even if gas is generated due to repeated charging and discharging, the uneven portion expands and contracts to suppress thermal expansion.

[0008] Furthermore, by forming the portion of the housing portion that faces the main surface of the electrode body in a shape that does not interfere with the other, adjacent laminate films can be brought into surface contact when modularized, ensuring stackability.

[0009] A laminate film according to a second aspect of the present invention is the laminate film according to the first aspect, wherein a bottom wall portion of the housing portion that faces a main surface of the electrode body is formed in a flat shape without irregularities.

[0010] In the laminate film according to claim 2, the bottom wall portion that faces the main surface of the electrode body is formed in a flat shape, so that if the battery cells are arranged so that their main surfaces overlap, stacking properties can be improved.

[0011] A battery cell according to claim 3 has an electrode assembly formed by laminating a positive electrode, a negative electrode, and a separator, and the laminate film according to claim 2 that houses the electrode assembly.

[0012] The battery cell according to claim 3 has the same effect as that of claim 2.

[0013] The battery module of claim 4 includes a case in which a plurality of battery cells as described in claim 3 are housed in an array, and the plurality of battery cells are arranged such that adjacent battery cells face each other with their bottom wall portions facing each other.

[0014] In the battery module according to claim 4, the multiple battery cells housed in the case are arranged with their bottom wall portions facing each other, so that there is no interference from uneven portions. Effect of the Invention

[0015] As described above, the laminate film, battery cell, and battery module according to the present invention ensure loading performance while suppressing thermal expansion in the laminate film that houses the electrode assembly. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic plan view showing a main part of a vehicle to which a battery pack according to an 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] 1 is a schematic cross-sectional view of a battery cell according to an embodiment. [Figure 6] FIG. 2 is a schematic cross-sectional view of a laminate film before sealing in an embodiment. [Figure 7] FIG. 11 is a schematic cross-sectional view of a battery cell according to a modified example. [Figure 8] FIG. 11 is a schematic cross-sectional view of a laminate film before sealing in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A battery module 11 to which a laminate film 22 according to an embodiment is applied will be described with reference to the drawings.

[0018] (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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] One or more cushioning materials (not shown) are housed inside the battery module 11. For example, the cushioning materials are elastically deformable thin plate-like members, and are arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 being the thickness direction. As an example in this embodiment, cushioning materials are arranged at both ends of the battery module 11 in the longitudinal direction and in the central portion in the longitudinal direction.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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 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. 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.

[0035] Fig. 5 is a schematic cross-sectional view of a battery cell 20 in an embodiment. As shown in Fig. 5, the battery cell 20 in this embodiment includes an electrode body 30 formed by laminating a positive electrode, a negative electrode, and a separator, and a laminate film 22 that houses the electrode body 30. The electrode body 30 constitutes, for example, a lithium ion battery, and lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, etc. are used as the active material of the positive electrode. Graphite, lithium titanate, etc. are used as the active material of the negative electrode. Furthermore, the inside of the battery cell 20 is filled with an electrolyte.

[0036] The laminate film 22 has a housing portion 32 for housing the electrode body 30, and is sealed with the electrode body 30 housed in the housing portion 32.

[0037] Fig. 6 is a schematic cross-sectional view of a laminate film 22 before sealing in an embodiment. As shown in Fig. 6, the laminate film 22 before sealing has a recess formed by embossing or the like, and this recess constitutes a storage section 32. The periphery of the recess (storage section 32) is a seal section 22A formed in a sheet shape, and the overlapped laminate films 22 are welded together at this seal section 22A.

[0038] Here, the storage section 32 is configured to include a bottom wall section 32A and a side wall section 32B. The bottom wall section 32A is a section that faces the main surface of the electrode body 30, and when constructing the battery module 11, adjacent battery cells are disposed so that their bottom walls 32A face each other.

[0039] The side wall 32B is a portion of the housing 32 that faces the peripheral end surface of the electrode body 30, and is formed in an uneven shape. For example, after the housing 32 is formed by embossing, only the side wall 32B is formed in an uneven shape by pressing. Therefore, the bottom wall 32A is formed in a flat shape without any unevenness.

[0040] (action) Next, the function of the laminate film 22 according to this embodiment will be described.

[0041] The laminate film 22 according to this embodiment includes a housing section 32 that houses the electrode body 30, and the housing section 32 is configured to include a side wall section 32B that faces the peripheral end face of the electrode body 30. Since an uneven portion is formed on at least a part of the side wall section 32B, even if gas is generated due to repeated charging and discharging, the uneven portion expands and contracts, thereby suppressing thermal expansion of the battery cell 20.

[0042] Furthermore, by making the bottom wall portion 32A in the storage section 32 opposite the main surface of the electrode body 30 flat, the flat surfaces of adjacent laminate films 22 come into contact with each other when modularized, and the uneven portions do not interfere with each other, ensuring stackability.

[0043] In particular, the battery cells 20 of this embodiment are arranged in the battery module 11 such that the bottom wall portions 32A face each other, so that there is no interference between the uneven portions.

[0044] In the above embodiment, a single cup embossed structure is used in which one recess is embossed in the laminate film 22, but this is not limited to this, and a double cup embossed structure as shown in Figures 7 and 8 may also be adopted.

[0045] (Modification) Fig. 7 is a schematic cross-sectional view of a battery cell 50 in a modified example, and Fig. 8 is a schematic cross-sectional view of a laminate film 52 in the modified example before sealing. As shown in Fig. 7, the battery cell 50 in this modified example is configured to include an electrode body 30 and a laminate film 52 that houses the electrode body 30.

[0046] The laminate film 52 has a housing portion 54 for housing the electrode body 30, and is sealed with the electrode body 30 housed in this housing portion 54.

[0047] 8, the laminate film 52 before sealing has two recesses formed by embossing or the like, and these recesses are overlapped to form the storage section 54. Moreover, the periphery of each recess (storage section 54) is a seal section 52A formed in a sheet shape, and the overlapped laminate films 52 are welded to each other at the seal section 52A.

[0048] Here, the recesses constituting the accommodation section 54 each include a bottom wall section 54A and a side wall section 54B. The bottom wall section 54A is a section that faces the main surface of the electrode body 30, and when constructing a battery module, adjacent battery cells are disposed with their bottom walls 54A facing each other.

[0049] The side wall 54B is a portion of the housing 54 that faces the peripheral end surface of the electrode body 30, and is formed in an uneven shape. For example, after the housing 54 is formed by embossing, only the side wall 54B is formed in an uneven shape by pressing. Therefore, the bottom wall 54A is formed in a flat shape without any unevenness.

[0050] According to this modification, by adopting a double cup embossed structure, even if the electrode body 30 is thick, it can be accommodated.

[0051] The laminate film 22, the battery cell 20, and the battery module 11 according to the present embodiment have been described above, but the present invention is not limited to this and can be embodied in various forms without departing from the spirit of the present invention. For example, in the above embodiment, the four side walls 32B constituting the storage section 32 are all formed unevenly, but the present invention is not limited to this and only some of the side walls 32B may be formed unevenly.

[0052] In the above embodiment, the bottom wall portion 32A is formed in a flat shape, but this is not limited thereto. For example, the bottom wall portion 32A may be formed with a plurality of recesses. In this case, it is possible to suppress thermal expansion without interfering with adjacent battery cells.

[0053] Furthermore, in the above embodiment, the side wall portion 32B is formed with a generally wavy uneven portion when viewed from the side, but this is not limited thereto. For example, the side wall portion 32B may be formed with a generally wavy uneven portion when viewed from the bottom wall portion 32A. In other words, the shape of the uneven portion is not limited.

[0054] Regarding the above embodiment, the following notes are disclosed.

[0055] (Appendix 1) A laminate film that includes an accommodation portion for accommodating an electrode body and seals the electrode body in a accommodated state, A laminate film having an uneven portion formed on at least a part of a side wall portion that faces the peripheral end surface of the electrode body in the housing portion. (Appendix 2) 2. The laminate film according to claim 1, wherein the bottom wall portion of the storage section that faces the main surface of the electrode body is formed in a flat shape without any irregularities. (Appendix 3) an electrode assembly formed by laminating a positive electrode, a negative electrode, and a separator; The laminate film according to claim 1 or 2, which houses the electrode body; A battery cell having (Appendix 4) A case in which a plurality of battery cells according to appendix 3 are housed in an array, The plurality of battery cells are arranged as a battery module in which adjacent battery cells are arranged with the bottom wall portions facing each other. [Explanation of symbols]

[0056] 11 Battery module 20 Battery Cells 22 Laminating film 30 Electrode body 32, 54 Storage section 32A, 54A bottom wall 32B, 54B side wall part

Claims

1. A laminate film that includes an accommodation portion for accommodating an electrode body and seals the electrode body in a accommodated state, A laminate film having an uneven portion formed on at least a part of a side wall portion that faces the peripheral end surface of the electrode body in the housing portion.

2. The laminate film according to claim 1 , wherein a bottom wall portion of the housing portion facing the main surface of the electrode body is formed in a flat shape without irregularities.

3. an electrode assembly formed by laminating a positive electrode, a negative electrode, and a separator; The laminate film according to claim 2 which houses the electrode body; A battery cell having

4. A case in which a plurality of battery cells according to claim 3 are housed in an array, The plurality of battery cells are arranged as a battery module in which adjacent battery cells are arranged with the bottom wall portions facing each other.

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