Battery Module

Abstract

To achieve high heat-exchange efficiency between a cell laminate and a case through a heat-conducting adhesive agent while reducing temperature variation in cells.SOLUTION: A battery module comprises a cell laminate formed by staking a plurality of cells, a case for storing the cell laminate, a heat-conducting adhesive agent, and a heat dissipation layer. The heat-conducting adhesive agent is disposed between the cell laminate and the case so as to come into contact with undersides of the plurality of cells and a bottom face of the case. The heat dissipation layer is provided so as to fill each gap between adjacent cells of the plurality of cells. The heat dissipation layer includes a first heat dissipation layer arranged on at least a lower end of one of side faces facing each other of each pair of adjacent cells of the plurality of cells.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a battery module that includes a thermally conductive adhesive provided in the space between the lower end of a cell stack and the bottom surface of a module housing, and a heat dissipation foam that is mixed with the thermally conductive adhesive in the space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-522096 Summary of the Invention [Problem to be solved by the invention]

[0004] Gaps exist between adjacent cells in the cell stack, and if the thermally conductive adhesive seeps into these gaps, the presence of the thermally conductive adhesive will cause temperature variations in the cells.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a battery module that suppresses temperature variation among cells while enabling good heat exchange between the cell stack and the case via a thermally conductive adhesive. [Means for solving the problem]

[0006] The battery module according to the present disclosure includes a cell stack formed by stacking a plurality of cells, a case for housing the cell stack, a thermally conductive adhesive, and a heat dissipation layer. The thermally conductive adhesive is disposed between the cell stack and the case so as to contact the lower surfaces of the plurality of cells and the bottom surface of the case. The heat dissipation layer is provided so as to close gaps between adjacent cells included in the plurality of cells. The heat dissipation layer includes a first heat dissipation layer disposed at a lower end of at least one of the opposing side surfaces of the adjacent cells.

[0007] The heat dissipation layer may further include a second heat dissipation layer disposed above the first heat dissipation layer on at least one of the opposing side surfaces of adjacent cells.

[0008] The first heat dissipation layer may be disposed so as to extend along the bottom side of the cell in which the first heat dissipation layer is disposed.

[0009] The heat dissipation layer may be coated onto the cell in which it is disposed. Effect of the Invention

[0010] According to the present disclosure, it is possible to suppress temperature variations in the cells while ensuring good heat transfer between the cell stack and the case via the thermally conductive adhesive. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view illustrating a schematic configuration of a battery module according to an embodiment. [Diagram 2] 2 is a view of the cell shown in FIG. 1 as viewed from stacking direction D1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, elements common to the various drawings will be denoted by the same reference numerals, and duplicated descriptions will be omitted or simplified.

[0013] 1. Battery module configuration Fig. 1 is a cross-sectional view that shows a schematic configuration of a battery module 1 according to an embodiment. More specifically, Fig. 1 shows a cross-section of the battery module 1 taken along line AA in Fig. 2. Fig. 2 shows a cell 14 shown in Fig. 1 as viewed from stacking direction D1. The battery module 1 is mounted on, for example, a vehicle, and supplies power to an electric motor that drives the vehicle.

[0014] The battery module 1 includes a cell stack 10 and a case 12. The cell stack 10 is formed by stacking a plurality of cells 14. The case 12 houses the cell stack 10.

[0015] More specifically, in the example shown in FIG. 1, three cells 14 are stacked. As shown in FIG. 2, a pair of electrode terminals, i.e., a positive terminal 16 and a negative terminal 18, are provided on the upper surface 14a of each cell 14. The case of each cell 14 is formed using, for example, aluminum or stainless steel (SUS). In addition, the case of each cell 14 may have a film such as a PET (polyethylene terephthalate resin) film as an exterior material. Each cell 14 is, for example, a prismatic battery having a substantially rectangular parallelepiped shape. The cell stack 10 and the case 12 also have a substantially rectangular parallelepiped shape.

[0016] The battery module 1 includes a thermally conductive adhesive 20. The thermally conductive adhesive 20 is disposed between the cell stack 10 and the case 12. The lower surface 14b of each cell 14 and the bottom surface 12a of the case 12 are in contact with each other via the thermally conductive adhesive 20. The thermally conductive adhesive 20 is an adhesive made of a material having high thermal conductivity, such as a thermally conductive silicone adhesive or a thermally conductive epoxy adhesive. More specifically, as shown in FIG. 1, the thermally conductive adhesive 20 is filled so as to cover the entire bottom surface 12a of the case 12, for example.

[0017] The battery module 1 further includes a heat dissipation layer 30 as shown in Fig. 1. In the example shown in Fig. 1, the heat dissipation layer 30 includes a first heat dissipation layer 32 and a second heat dissipation layer 34. The first heat dissipation layer 32 and the second heat dissipation layer 34 are each provided so as to close the gaps G1 between adjacent cells 14. More specifically, the first heat dissipation layer 32 and the second heat dissipation layer 34 are each provided in the gaps G1 between all adjacent cells 14 included in the plurality of cells 14 constituting the cell stack 10.

[0018] The first heat dissipation layer 32 is provided at the lower end of the adjacent cells 14 (more specifically, at the lower end in the up-down direction D2 of the cell stack 10). The first heat dissipation layer 32 is, for example, coated on the cell 14 in which the first heat dissipation layer 32 is arranged. Specifically, in the example shown in FIG. 1, a coating layer 36 is provided at the lower end of both of the side surfaces (opposing surfaces) 14c facing each other of the adjacent cells 14. The tips of these coating layers 36 are in contact with each other. That is, in the example shown in FIG. 1, such a pair of coating layers 36 corresponds to the first heat dissipation layer 32. In addition, the opposing surfaces 14c are side surfaces of the cells 14 that are perpendicular to the stacking direction D1.

[0019] 2, the first heat dissipation layer 32, i.e., each of the pair of coating layers 36, is disposed so as to extend along the bottom side B of the cell 14 in which the first heat dissipation layer 32 is disposed. More specifically, the first heat dissipation layer 32 is formed so as to extend from one end to the other end of the opposing surface 14c in a direction D3 parallel to the bottom side B.

[0020] Furthermore, the height of the coating layer 36 (more specifically, the width of the coating layer 36 in the vertical direction D2) may be, for example, 1 / 10 (in mm) or more of the height of the cells 14 (more specifically, the width of the cells 14 in the vertical direction D2). This allows for good "heat transfer" and "adjustment of variation in the gap G1" to be described later.

[0021] The coating layer 36 is configured to include a material with high heat dissipation properties. Specifically, the coating layer 36 is configured, for example, by combining the following resin-based material and carbon-based material. The resin-based material is, for example, polyolefin resin, polyester resin, or styrene-butadiene rubber. It is desirable that the resin-based material is soluble or dispersible in a solvent with a boiling point of 100°C or less. In this way, the coating layer 36 can be formed by applying the resin-based material combined with the carbon-based material to the opposing surface 14c of each cell 14. Then, the coating layer 36 can be dried in an environment of 40°C or less.

[0022] The carbon-based material is, for example, a graphite material (natural graphite or artificial graphite). The particle size of the graphite material may be, for example, 100 μm or less. The carbon-based material may also be one in which, for example, 10 wt % or less of fibrous carbon or carbon nanotubes is contained in the graphite material. By adding fibrous carbon or carbon nanotubes to the graphite material in this way, the resin component ratio in the coating layer 36 may be reduced to improve heat dissipation.

[0023] On the other hand, as shown in FIG. 1, the second heat dissipation layer 34 is provided on the adjacent cell 14 at a position above the first heat dissipation layer 32. The "upper position" here corresponds to, for example, a position near the upper surface 14a of the cell 14, that is, a position near the upper end. Like the first heat dissipation layer 32, the second heat dissipation layer 34 is, for example, coated on the cell 14 in which the second heat dissipation layer 34 is disposed. Specifically, in the example shown in FIG. 1, coating layers 38 are provided at "upper positions" on both of the mutually opposing side surfaces (opposing surfaces) 14c of the adjacent cells 14. The tips of these coating layers 38 are in contact with each other. That is, in the example shown in FIG. 1, such a pair of coating layers 38 corresponds to the second heat dissipation layer 34.

[0024] 2, the second heat dissipation layer 34, i.e., each of the pair of coating layers 38, is formed so as to extend from one end to the other end of the opposing surface 14c in the direction D3. The height of the coating layer 38 is set to be the same as the height of the above-mentioned coating layer 36. The material of the coating layer 38 is the same as the material of the above-mentioned coating layer 36.

[0025] 2.Effects In a battery module such as the battery module 1 in which a plurality of cells are housed in a case, it is possible to use thermal conduction between the cell and the case by contacting the case with the cell in order to cool and heat each cell. However, when the cell is directly contacted with the case, a gap is generated between the cell and the case. Therefore, a thermally conductive adhesive such as the thermally conductive adhesive 20 is used as a thermally conductive member between the cell and the case. One of the problems in the configuration of such a battery module is unevenness in the adhesive area of ​​the thermally conductive adhesive to the cell. Specifically, since there is a gap between adjacent cells, the thermally conductive adhesive provided between the lower surface of each cell and the bottom surface of the case gets into the gap. Since the thermal conduction between the cell and the case is performed via the thermally conductive adhesive, unevenness in the adhesive area causes temperature variation in the cell. More specifically, temperature variation occurs between the parts of the side surfaces of adjacent cells that are in contact with the thermally conductive adhesive and the parts that are not in contact with the thermally conductive adhesive.

[0026] In view of the above-mentioned problems, in the battery module 1 according to the present embodiment, a heat dissipation layer 30 is provided so as to close the gap G1 between the adjacent cells 14. The heat dissipation layer 30 includes a first heat dissipation layer 32 (coating layer 36) disposed at the lower ends of both of the opposing side surfaces (opposing surfaces) 14c of the adjacent cells 14. This makes it possible to prevent the thermally conductive adhesive 20 from entering the gap G1 during the manufacture of the battery module 1 by utilizing the first heat dissipation layer 32. Then, during the use of the battery module 1, the temperature variation of the cells 14 can be reduced by utilizing the transfer of heat between the first heat dissipation layer 32, which has high heat dissipation properties, and the adjacent cells 14 and the thermally conductive adhesive 20.

[0027] As described above, the battery module 1 of this embodiment makes it possible to effectively transfer heat between the cell stack 10 (multiple cells 14) and the case 12 via the thermally conductive adhesive 20 while suppressing temperature variation among the cells 14.

[0028] The first heat dissipation layer 32 also contributes to appropriately adjusting the gap G1 between the adjacent cells 14. The heat dissipation layer 30 according to this embodiment includes not only the first heat dissipation layer 32 but also the second heat dissipation layer 34 (coating layer 38). The second heat dissipation layer 34 is disposed above the first heat dissipation layer 32 on both of the opposing side surfaces (opposing surfaces) 14c of the adjacent cells 14. This configuration makes it possible to reduce temperature variations in the cells 14 while more effectively adjusting the gap G1 compared to a configuration including only the first heat dissipation layer 32. More specifically, it is possible to reduce temperature variations in the cells 14 while making it possible to adjust the variations in the gap G1 above and below in the vertical direction D2 (see FIG. 1).

[0029] Moreover, the first heat dissipation layer 32 according to this embodiment is disposed so as to extend along the bottom side B of the cell 14 in which the first heat dissipation layer 32 is disposed. More specifically, the first heat dissipation layer 32 is formed so as to extend from one end to the other end of the opposing surface 14c in the direction D3 parallel to the bottom side B. This makes it possible to more reliably prevent the thermally conductive adhesive 20 from entering the gap G1 during the manufacture of the battery module 1.

[0030] 1, each of the three cells 14 constituting the cell stack 10 has coating layers 36 and 38 on all of the side surfaces (including the opposing surface 14c) perpendicular to the stacking direction D1. Therefore, as shown in FIG. 1, the gap G2 between the cells 14 located at each end of the stacking direction D1 and the side surface 12b of the case 12 is also filled by the coating layers 36 and 38. This makes it possible to promote the transfer of heat between the cells 14 located at each end of the stacking direction D1 and the case 12 via the coating layers 36 and 38.

[0031] In the above-described embodiment, the battery module 1 includes both the first heat dissipation layer 32 and the second heat dissipation layer 34 as the heat dissipation layer 30. However, instead of this example, the "battery module" according to the present disclosure may include the first heat dissipation layer without including the second heat dissipation layer.

[0032] In the above-described embodiment, the coating layer 36 provided on both opposing surfaces 14c of the adjacent cells 14 is used to form the first heat dissipation layer 32. Alternatively, the coating layer 36 may be formed on only one of the opposing side surfaces (opposing surfaces) of the adjacent cells. The same applies to the coating layer 38 constituting the second heat dissipation layer 34. [Explanation of symbols]

[0033] 1 battery module, 10 cell stack, 12 case, 12a bottom surface of case, 14 cell, 14b bottom surface of cell, 14c opposing surface of cell, 16 positive electrode terminal, 18 negative electrode terminal, 20 thermally conductive adhesive, 30 heat dissipation layer, 32 first heat dissipation layer, 34 second heat dissipation layer, 36, 38 coating layer

Claims

1. A cell stack in which a plurality of cells are stacked; A case that houses the cell stack; a thermally conductive adhesive disposed between the cell stack and the case so as to contact lower surfaces of the plurality of cells and a bottom surface of the case; a heat dissipation layer provided to fill gaps between adjacent cells included in the plurality of cells; Equipped with The heat dissipation layer is coated on a cell in which the heat dissipation layer is disposed, The heat dissipation layer is a first heat dissipation layer disposed on at least one lower end of first side surfaces of the adjacent cells facing each other; a second heat dissipation layer disposed above the first heat dissipation layer and spaced apart from the first heat dissipation layer in the vertical direction of the cell stack, on at least one of the first side surfaces of the adjacent cells facing each other; Including, The first and second heat dissipation layers are also disposed on the second side surfaces of the cells located at the respective ends in the stacking direction of the cells, the second side surfaces being opposed to the case, so as to close gaps between the second side surfaces of the cells and the case. A battery module comprising:

2. The first heat dissipation layer is disposed so as to extend along the bottom side of the cell in which the first heat dissipation layer is disposed. The battery module according to claim 1 .

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