Battery module

Abstract

To suppress influences, caused by heat of an adjacent battery cell, upon the other battery cell while preventing the battery cell and a restraining member from being electrically short-circuited.SOLUTION: Disclosed is a battery module comprising a laminate, which is configured by laminating a plurality of battery cells, and a restraining member for restraining the laminate. The battery module comprises an insulative heat conduction material which is interposed between side faces of the battery cells and the restraining member. The restraining member includes a first restraining part in contact with the heat conduction material in contact with a first battery cell and a second restraining part arranged in parallel with the first restraining part and in contact with the heat conduction material in contact with a second battery cell. The first restraining part and the second restraining part are in contact with the heat conduction material while skipping at least one battery cell in such a manner that heat of one of adjacent battery cells is not conducted to the other via the restraining member. A clearance enough for preventing the battery cell from being in contact with the restraining member or an insulation material having a heat insulation property is provided between the first battery cell and the second restraining part and between the second battery cell and the first restraining part.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent Document 1 discloses that in a battery module in which multiple battery cells are stacked, when one of the battery cells abnormally heats up, the thermal resistance between adjacent battery cells is increased to prevent heat transfer from the abnormally heated battery cell to the adjacent battery cell. In the configuration described in Patent Document 1, heat transfer between the battery cells is controlled by a band member that connects a pair of end plates and holds the battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 025567 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the configuration described in Patent Document 1 has a structure in which the metal restraining member comes into direct contact with the cell case of the battery cell, which may cause a short circuit between the cell case of the battery cell and the restraining member, resulting in heat generation due to this short circuit.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a battery module that can prevent electrical short-circuiting between battery cells and restraining members while suppressing the influence of heat from adjacent battery cells on other battery cells. [Means for solving the problem]

[0006] The present invention relates to a battery module comprising a stack in which a plurality of battery cells and a plurality of heat insulating materials are alternately arranged and stacked, and a restraining member that restrains the stack, the restraining member being disposed opposite a side surface of the stack and extending along the stacking direction of the stack, the restraining member being disposed opposite a side surface of the stack, and comprising an insulating thermally conductive material interposed between the side surface of the battery cell and the restraining member, the plurality of battery cells including adjacent first and second battery cells, the restraining member being disposed parallel to the first restraining portion and in contact with the thermally conductive material that contacts the first battery cell, and a second restraint portion in contact with the thermally conductive material that contacts the first battery cell and the second battery cell, and the first restraint portion and the second restraint portion each contact the thermally conductive material for at least every other battery cell so that heat from one of the adjacent first and second battery cells is not transferred to the other battery cell via the restraint member, and between the side surface of the first battery cell and the second restraint portion, there is provided a gap that prevents the side surface of the battery cell from contacting the restraint member, or an insulating material with thermal insulation properties. [Effects of the Invention]

[0007] In the present invention, it is possible to prevent an electrical short circuit between the battery cell and the restraining member, while suppressing the influence of heat from one adjacent battery cell on the other battery cell. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams illustrating a battery module according to an embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating a battery module. [Figure 3] FIG. 2 is a diagram illustrating a thermally conductive material and an insulating material. [Figure 4] 10A and 10B are diagrams illustrating a structure in which a restraining member and a thermally conductive material come into contact with each other. [Figure 5] FIG. 10 is a diagram for explaining a case where heat is transferred from a heated battery cell. [Figure 6]10A and 10B are diagrams illustrating a structure in which a slit is provided in a restraining member. [Figure 7] 10A and 10B are diagrams illustrating a structure in which a cross member provided on a lower case of the battery pack comes into contact with a thermally conductive material. [Figure 8] FIG. 10 is a diagram illustrating a structure in which three restraining members are arranged on one side of a battery cell. [Figure 9] FIG. 10 is a diagram illustrating a structure in which three restraining members are arranged on one side surface. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a battery module according to an embodiment of the present invention will be specifically described, although the present invention is not limited to the embodiment described below.

[0010] As shown in FIG. 1, a battery module 1 includes a stack 4 in which multiple battery cells 2 and multiple heat insulating materials 3 are alternately arranged and stacked, a pair of end plates 5 that sandwich the stack 4 from both sides in the stacking direction, a thermally conductive material 6 with insulating properties, and an insulating material 7 with thermal insulating properties. As shown in FIG. 2, the battery module 1 includes a restraint band 8 that restrains the stack 4. In the battery module 1, the battery cells 2 are cooled from the lower surface 2a of the battery cells 2 by a cooler 21. The cooler 21 cools the lower surface 2a of the battery cells 2 via a thermally conductive material 22. The thermally conductive material 22 is interposed between the lower surface 2a of the battery cells 2 and the cooler 21. The battery module 1 is housed inside a lower case 9. The battery module 1 is housed in a battery pack case (pack case). The pack case includes a lower case 9 that houses the battery module 1.

[0011] As shown in Figure 1, in a stack 4, adjacent battery cells 2 are insulated by heat insulating material 3. A pair of end plates 5 are arranged on both ends of the stack 4 in the stacking direction. Heat insulating material is provided between the end plates 5 and the battery cells 2. As shown in Figure 2, the stack 4 is constrained by restraint bands 8 in a state where it is compressed in the stacking direction by a compressive load applied from the pair of end plates 5. The restraint bands 8 are restraint members whose both ends in the stacking direction are fixed to the pair of end plates 5. The end plates 5 and restraint bands 8 are integrated by bolting.

[0012] As shown in Figures 2 to 4, the restraint bands 8 are positioned opposite the side surfaces of the stack 4 and are side bands that extend in the stacking direction of the stack 4. In the battery module 1, the restraint bands 8 are provided in positions opposite both side surfaces of the stack 4. The restraint bands 8 face the side surfaces 2b of the battery cells 2. On the side surfaces 2b of the battery cells 2, thermally conductive materials 6 and insulating materials 7 are provided in two layers, one above the other. The thermally conductive materials 6 and insulating materials 7 are interposed between the side surfaces 2b of the battery cells 2 and the restraint bands 8. The restraint bands 8 form a heat dissipation path that dissipates heat from the battery cells 2.

[0013] The thermally conductive material 6 is a flat plate-shaped member provided on the side surface 2b of the battery cell 2, and forms a thermal path that transfers heat from the battery cell 2 to the restraint band 8. The thermally conductive material 6 is interposed between the side surface 2b of the battery cell 2 and the restraint band 8. As shown in FIG. 4, the thermally conductive material 6 is in surface contact with the side surface 2b of the battery cell 2 and also with the restraint band 8. The thermally conductive material 6 has sufficient thermal conductivity to draw away heat when the battery cell 2 generates abnormal heat. The thermally conductive material 6 has, for example, a thermal conductivity of 1 W / mk or more and an electrical resistance of 10 MΩ or more.

[0014] The insulating material 7 is a flat plate-shaped member provided on the side surface 2b of the battery cell 2, and provides thermal insulation between the battery cell 2 and the restraint band 8. The insulating material 7 is interposed between the side surface 2b of the battery cell 2 and the restraint band 8. The insulating material 7 is made of a material with high thermal resistance, such as mica.

[0015] In the battery module 1 configured in this manner, when one of the battery cells 2 emits smoke, in order to prevent the adjacent battery cells 2 from emitting smoke, the battery module 1 has a heat dissipation path that transfers heat from the smoking battery cell 2 to other battery cells 2 without inducing another heat generation mode. The battery module 1 has a structure in which at least every other battery cell 2 and the restraint bands 8 are in contact with the thermally conductive material 6 so that the heat from the adjacent battery cells 2 does not leak through the restraint bands 8.

[0016] The plurality of battery cells 2 includes a first battery cell 2A and a second battery cell 2B adjacent to the first battery cell 2A. The plurality of battery cells 2 includes adjacent first battery cell 2A and second battery cell 2B. The thermally conductive material 6 includes a first thermally conductive material 6A in contact with the first battery cell 2A and a second thermally conductive material 6B in contact with the second battery cell 2B. The insulating material 7 includes a first insulating material 7A in contact with the first battery cell 2A and a second insulating material 7B in contact with the second battery cell 2B. The restraint bands 8 include a first restraint band 8A and a second restraint band 8B.

[0017] A first thermally conductive material 6A and a first insulating material 7A are provided in two upper and lower layers on the side surface 2b of the first battery cell 2A. A second thermally conductive material 6B and a second insulating material 7B are provided in two upper and lower layers on the side surface 2b of the second battery cell 2B. A first restraint band 8A contacts the first thermally conductive material 6A and the second insulating material 7B. The first restraint band 8A alternately contacts the first thermally conductive material 6A and the second insulating material 7B in the stacking direction. The second restraint band 8B is arranged parallel to the first restraint band 8A and contacts the second thermally conductive material 6B and the first insulating material 7A. The second restraint band 8B alternately contacts the second thermally conductive material 6B and the first insulating material 7A in the stacking direction. In the restraint band 8, the first restraint band 8A is the first restraining portion, and the second restraint band 8B is the second restraint portion. When there is no particular distinction between the first and second, the symbols A and B are omitted.

[0018] The first restraint bands 8A form a heat dissipation path that dissipates heat from the first battery cell 2A to a location other than the adjacent cell. As shown in Fig. 5, the first restraint bands 8A form a heat dissipation path that prevents heat from the first battery cell 2A, which is input from the first thermally conductive material 6A, from entering the adjacent second battery cell 2B. The second restraint bands 8B form a heat dissipation path that dissipates heat from the second battery cell 2B to a location other than the adjacent cell. The second restraint bands 8B form a heat dissipation path that prevents heat from the second battery cell 2B, which is input from the second thermally conductive material 6B, from entering the adjacent first battery cell 2A.

[0019] The first restraint band 8A and the second restraint band 8B each contact the thermally conductive material 6 for at least every other battery cell 2 between the first battery cell 2A and the second battery cell 2B adjacent to each other, so that heat from one battery cell 2 is not transferred to the other battery cell 2 via the restraint band 8. As shown in FIG. 5 , an insulating material 7 is provided in areas that should not be used as a thermal path from the battery cell 2 to the restraint band 8. A portion where the thermally conductive material 6 is not provided is provided between the first restraint band 8A and the second battery cell 2B. A portion where the thermally conductive material 6 is not provided is provided between the second restraint band 8B and the first battery cell 2A. An insulating material 7 is provided in this portion where the thermally conductive material 6 is not provided. As a result, if one of the battery cells 2 emits smoke, the heat from that smoking battery cell 2 will not be transferred to the adjacent cells.

[0020] In the battery module 1, when one side of the laminate 4 has the structure shown in FIG. 5, the other side of the laminate 4 has a structure that is upside down from the structure shown in FIG. 5. Taking the first battery cell 2A as an example, on one side 2b of the first battery cell 2A, as shown in FIG. 4, the first thermally conductive material 6A is arranged in the upper tier and the first insulating material 7A is arranged in the lower tier. In this case, on the other side 2b of the first battery cell 2A, the first insulating material 7A is arranged in the upper tier and the first thermally conductive material 6A is arranged in the lower tier. This arrangement can also be applied to the second battery cell 2B.

[0021] As described above, according to the embodiment, when any battery cell 2 in the battery module 1 generates abnormal heat, it is possible to prevent heat from being transferred from that battery cell 2 to an adjacent battery cell 2, and to prevent a short circuit between the battery cell 2 and the restraint band 8. This makes it possible to prevent a thermal chain reaction caused by multiple battery cells 2.

[0022] The insulating material 7 does not necessarily have to be provided. For example, in the areas where the thermally conductive material 6 is not provided, a gap may be provided that prevents contact between the side surface 2b of the battery cell 2 and the restraint band 8. In the areas where the thermally conductive material 6 is not provided, it is sufficient that either a gap that prevents contact between the battery cell 2 and the restraint band 8 or the insulating material 7 is provided.

[0023] Furthermore, the restraint band 8 is not limited to a structure consisting of two members, including the first restraint band 8A and the second restraint band 8B. The restraint band 8 may be composed of a single member, as shown in FIG. 6. The restraint band 8 shown in FIG. 6 includes a first restraint portion 81, a second restraint portion 82, and a slit 83. The first restraint portion 81, like the first restraint band 8A, forms a heat dissipation path for dissipating heat from the first battery cell 2A. The second restraint portion 82, like the second restraint band 8B, forms a heat dissipation path for dissipating heat from the second battery cell 2B. The first restraint portion 81 and the second restraint portion 82 are positioned opposite the side surfaces of the stack 4 and extend in the stacking direction across all of the battery cells 2 in the stack 4. On one side surface of the stack 4, the first restraint portion 81 is positioned on the upper side of the stack 4, and the second restraint portion 82 is positioned on the lower side of the stack 4. The slit 83 extends along the stacking direction in the center of the height direction so that the first restraint portion 81 and the second restraint portion 82 are separated into two upper and lower stages. The slit 83 extends across the entire side surface of the stack 4. The slit 83 can prevent heat conduction from the first restraint portion 81 to the second restraint portion 82, and from the second restraint portion 82 to the first restraint portion 81. The restraint band 8 may be divided, or may have a structure with the slit 83 open. In other words, it is sufficient that the thermal mass can be divided.

[0024] Furthermore, in the battery module 1, the restraining members that restrain the stack 4 are not limited to the restraining bands 8. The restraining members may be cross members 10 of the lower case 9. The lower case 9 is provided with cross members 10 that divide the storage chambers of the battery module 1. The cross members 10 are integrated with the lower case 9. As shown in FIG. 7 , the cross members 10 are disposed in positions that face the side surfaces 2b of the battery cells 2. In a modified battery module 1, the cross members 10 of the pack case form heat dissipation paths instead of the restraining bands 8. The restraining members that come into contact with the thermally conductive material 6 are not limited to the restraining bands 8. The heat dissipation path that dissipates the heat of the battery cells 2 that is input from the thermally conductive material 6 may be members other than the restraining bands 8. The cross members 10 function as restraining members that restrain the stack 4.

[0025] The cross member 10 is positioned opposite the side of the stack 4 and extends in the stacking direction to cross all of the battery cells 2 in the stack 4. The cross member 10 includes a first cross portion 11 and a second cross portion 12. A slit is provided between the first cross portion 11 and the second cross portion 12 in the height direction. On one side of the stack 4, the first cross portion 11 is positioned on the upper side of the stack 4, and the second cross portion 12 is positioned on the lower side of the stack 4. The slit extends along the stacking direction in the center of the height direction so that the first cross portion 11 and the second cross portion 12 are separated into two upper and lower sections. The slit extends across the entire side of the stack 4. The slit prevents heat conduction from the first cross portion 11 to the second cross portion 12 and from the second cross portion 12 to the first cross portion 11. In the cross member 10, the first cross portion 11 is a first restraining portion, and the second cross portion 12 is a second restraining portion.

[0026] Furthermore, the arrangement pattern of the thermally conductive material 6 is not particularly limited as long as the structure does not allow adjacent battery cells 2 to come into contact with the same restraint band 8 at the same time. As shown in Fig. 4, the thermally conductive material 6 may be arranged in different patterns on both side surfaces 2b of the battery cell 2. As shown in Fig. 8, the restraint band 8 may be divided into three.

[0027] As shown in FIGS. 8 and 9, the battery module 1 of the modified example has a structure in which restraint bands 8 are arranged in three vertical tiers. The restraint bands 8 include a first restraint band 8A, a second restraint band 8B, and a third restraint band 8C. One thermally conductive material 6 and two insulating materials 7 are arranged in three vertical tiers on one side surface 2b of each battery cell 2. The multiple battery cells 2 include a third battery cell 2C. In this case, the first battery cell 2A is adjacent to both the second battery cell 2B and the third battery cell 2C. The second battery cell 2B is adjacent to both the first battery cell 2A and the third battery cell 2C. The third battery cell 2C is adjacent to both the second battery cell 2B and the first battery cell 2A. The third restraint band 8C forms a heat dissipation path for dissipating heat from the third battery cell 2C. A third thermally conductive material 6C and a third insulating material 7C are provided on the side surface 2b of the third battery cell 2C. A third thermally conductive material 6C and a third insulating material 7C are interposed between the side surface 2b of the third battery cell 2C and the third restraint band 8C. The third restraint band 8C is a third restraint portion.

[0028] Furthermore, a cooler 21 or a thermal mass having the same effect as the cooler 21 may be provided on the underside of the laminate 4. The cooler 21 or the thermal mass may be disposed inside the lower case 9 or below the lower case 9. [Explanation of symbols]

[0029] 1 Battery Module 2 battery cells 2b side 2A 1st battery cell 2B Second battery cell 3. Insulation 4 Laminate 5 End Plate 6. Thermal Conductive Materials 6A First thermal conductive material 6B Second thermal conductive material 7. Insulation 7A First Insulator 7B Second insulating material 8 Restraint band (restraint member) 8A First restraint band (first restraint part) 8B Second restraint band (second restraint part) 9 Lower case 10 Cross member (restraint member)

Claims

1. a stack in which a plurality of battery cells and a plurality of heat insulating materials are alternately arranged and stacked; a restraining member that restrains the stack; Equipped with the restraining member is a battery module that is disposed opposite a side surface of the stack and extends along a stacking direction of the stack, a thermally conductive material having insulating properties that is interposed between a side surface of the battery cell and the restraining member; the plurality of battery cells include a first battery cell and a second battery cell adjacent to each other; The restraining member is a first restraint portion in contact with the thermally conductive material in contact with the first battery cell; a second constraint portion disposed parallel to the first constraint portion and in contact with the thermally conductive material in contact with the second battery cell; the first restraining portion and the second restraining portion each contact the thermally conductive material with at least every other battery cell so that heat from one of the adjacent first and second battery cells is not transferred to the other battery cell via the restraining member; Between the side surface of the first battery cell and the second restraining portion, and between the side surface of the second battery cell and the first restraining portion, there is provided a gap large enough to prevent contact between the side surface of the battery cell and the restraining member, or an insulating material having thermal insulation properties is provided. A battery module characterized by:

2. the insulating material is provided between a side surface of the first battery cell and the second constraining portion, and between a side surface of the second battery cell and the first constraining portion; the insulating material is interposed between the side surface of the battery cell and the restraining member; the first restraint portion alternately contacts the thermally conductive material in contact with the first battery cell and the thermal insulating material in contact with the second battery cell in the stacking direction; The second restraint portion alternately contacts the thermally conductive material in contact with the second battery cell and the thermal insulating material in contact with the first battery cell in the stacking direction. The battery module according to claim 1 .

3. The thermally conductive material has a thermal conductivity of 1 W / mk or more and an electrical resistance of 10 MΩ or more. The battery module according to claim 2 .

4. a pair of end plates disposed on both ends of the stacked body in the stacking direction and sandwiching the stacked body from both sides in the stacking direction; The restraining member is a band member whose both ends in the stacking direction are fixed to the pair of end plates. The battery module according to claim 3 .

5. the laminate is housed in a lower case of a battery pack, The restraining member is a cross member integrated with the lower case. The battery module according to claim 3 .

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