Batteries and cushioning sheets

Abstract

The battery comprises a plurality of cells, a plurality of buffer sheets 100 each arranged between adjacent cells, and a refrigerant passage for allowing the refrigerant to flow through the area between adjacent cells where the buffer sheets 100 are arranged, wherein the buffer sheet 100 comprises a flat plate portion 110, a plurality of protrusions 120 protruding from both sides of the flat plate portion 110, and a plurality of through holes 130 provided so as to penetrate both sides of the flat plate portion 110.

Description

[Technical field]

[0001] The present invention relates to a battery and a cushioning sheet. [Background technology]

[0002] In batteries such as lithium-ion batteries and all-solid-state batteries, a cell stack is generally formed by stacking multiple cells to obtain the required battery capacity and voltage. In these batteries, cells may expand or contract during charging and discharging, which can lead to a deterioration in quality. For example, lithium-ion batteries have an issue with the generation of needle-shaped crystals (dendrites) of lithium metal that occur when the batteries are repeatedly charged and discharged. If these crystals continue to grow, they can cause a short circuit between the positive and negative electrodes. In addition, in the case of all-solid-state batteries, it is known that the variation in surface pressure caused by expansion and contraction leads to variation in performance and affects the lifespan. Therefore, measures have been taken to suppress the expansion of cells by pressing the cells with an appropriate force, and to mechanically suppress the growth of the above crystals in lithium-ion batteries. For example, a technology is known in which a buffer sheet is placed between adjacent cells.

[0003] In addition, in the case of the above-mentioned batteries, the size and power output are increasing, and in order to suppress the deterioration of the cells, it is becoming increasingly necessary to suppress the high temperature caused by the increase in the amount of heat generated. Therefore, the technology of providing a structure for flowing a coolant between adjacent cells is being studied. However, if a general buffer sheet is used and a structure is provided in which the coolant flows in the area where the buffer sheet is arranged, it is considered that a stable cooling effect cannot be obtained. This point will be explained with reference to Figs. 5 and 6.

[0004] Fig. 5 is a plan view of a buffer sheet according to the conventional technology. Fig. 6 is a schematic cross-sectional view of a buffer sheet according to the conventional technology. Fig. 6(a) is a cross-sectional view taken along line BB in Fig. 5, and Fig. 6(b) is an enlarged view of the area surrounded by Y in Fig. 6(a) when a refrigerant is allowed to flow through the area where the buffer sheet according to the conventional technology is provided.

[0005] The buffer sheet 500 according to the conventional technology includes a flat plate portion 510 and a plurality of protruding portions 520 protruding from both sides of the flat plate portion 510. When the buffer sheet 500 is disposed between adjacent cells and a refrigerant flows between the cells, the refrigerant flows in a space formed in an area where the protruding portions 520 are not provided. However, depending on the usage environment, the flat plate portion 510 may bend. This causes a difference in the area of ​​the flow path formed on one side of the flat plate portion 510 and the area of ​​the flow path formed on the other side, resulting in a difference in cooling performance on both sides. In particular, when a plurality of cells are stacked vertically, the flat plate portion 510 is greatly bent.

[0006] 6(b) shows the state of the buffer sheet 500 when a refrigerant flows between the cells in a state where a plurality of cells are stacked vertically. In this figure, the positions of the surfaces of the cells are indicated by dotted lines 11. As shown in this figure, as the flat plate portion 510 bends downward, the flow path area of ​​the flow path R1 formed on the upper surface side of the flat plate portion 510 becomes wider, whereas the flow path area of ​​the flow path R2 formed on the lower surface side becomes narrower. Therefore, a difference occurs in the cooling performance on both sides of the flat plate portion 510. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2020 / 004039 [Patent Document 2] International Publication No. 2020 / 166357 [Patent Document 3] International Publication No. 2022 / 004076 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a battery and a buffer sheet capable of suppressing cell deterioration. [Means for solving the problem]

[0009] The present invention employs the following means to solve the above problems.

[0010] That is, the battery of the present invention is A plurality of cells; A plurality of buffer sheets each disposed between adjacent cells; a refrigerant passage for allowing a refrigerant to flow through a region between adjacent cells in which the buffer sheet is disposed; A battery comprising: The buffer sheet is A flat plate portion; A plurality of protruding portions protruding from both sides of the flat plate portion; A plurality of through holes provided to penetrate both surfaces of the flat plate portion; The present invention is characterized by comprising:

[0011] The buffer sheet of the present invention is A buffer sheet disposed between adjacent cells in a battery configured to allow a coolant to flow between the adjacent cells, comprising: A flat plate portion; A plurality of protruding portions protruding from both sides of the flat plate portion; A plurality of through holes provided to penetrate both surfaces of the flat plate portion; The present invention is characterized by comprising:

[0012] According to the present invention, since the buffer sheet is provided with a plurality of through holes, the coolant can move between the flow path formed on one side of the flat plate portion and the flow path formed on the other side of the flat plate portion. Also, the amount of deflection of the flat plate portion can be suppressed by the amount of the through holes.

[0013] The plurality of protrusions may be aligned in a direction in which the refrigerant flows and may be arranged in a plurality of rows.

[0014] This makes it difficult for the flow of the refrigerant to be hindered by the protruding portion.

[0015] The through holes may be arranged in a plurality of rows so as to extend in a direction in which the coolant flows.

[0016] This makes it possible to more reliably suppress the amount of bending of the flat plate portion, thereby suppressing the difference in flow path area on both sides of the flat plate portion caused by the bending of the flat plate portion.

[0017] The above configurations may be combined as much as possible. Effect of the Invention

[0018] As described above, according to the present invention, deterioration of cells can be suppressed. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram of a battery according to this embodiment. [Diagram 2] FIG. 2 is a plan view of a buffer sheet according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a buffer sheet according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing examples of various shapes of the protrusion. [Diagram 5] FIG. 5 is a plan view of a buffer sheet according to the prior art. [Figure 6] FIG. 6 is a schematic cross-sectional view of a buffer sheet according to the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions, and the like of the components described in the embodiment are not intended to limit the scope of the present invention unless otherwise specified.

[0021] (Example) A battery and a buffer sheet according to an embodiment of the present invention will be described with reference to Figs. 1 to 3. Fig. 1 is a schematic diagram of a battery according to this embodiment, and shows a schematic view of a part of the battery. Fig. 2 is a plan view of a buffer sheet according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view of a buffer sheet according to an embodiment of the present invention. Fig. 3(a) is a cross-sectional view taken along line AA in Fig. 2, and Fig. 3(b) is an enlarged view of the part surrounded by X in Fig. 3(a) when a refrigerant is caused to flow in the region where the buffer sheet according to this embodiment is provided.

[0022] <Battery> With reference to FIG. 1, a battery 1 according to an embodiment of the present invention will be described. The battery 1 is composed of a cell stack in which a plurality of cells (single cells) 10 are stacked. Specific examples of the battery 1 according to this embodiment include secondary batteries such as lithium ion batteries and all-solid-state batteries. The cell stack in such a battery is generally in a compressed state by a pair of clamping plates or the like. This allows a predetermined compressive force to act on the cell stack. In the battery 1 according to this embodiment, a buffer sheet 100 is disposed between each of the adjacent cells 10. In this way, the cell stack according to this embodiment includes a plurality of cells 10 and a plurality of buffer sheets 100 disposed between the adjacent cells 10. In this way, by providing the buffer sheet 100, even if the cells 10 expand and contract due to charging and discharging, an appropriate pressing force can be applied to each of the cells 10. Therefore, deterioration of the battery 1 can be suppressed, and the life of the battery 1 can be extended. The buffer sheet 100 is an elastic body made of an elastomer material such as rubber.

[0023] In the battery 1 according to this embodiment, a refrigerant passage is provided to allow the refrigerant to flow through the region between adjacent cells 10 where the buffer sheet 100 is arranged. This refrigerant passage is provided on both sides in the width direction of the cell stack. For convenience, in FIG. 1, the refrigerant passage on the left side is referred to as the first passage 21, and the refrigerant passage on the right side is referred to as the second passage 22. In FIG. 1, cross sections of the walls forming the first passage 21 and the second passage 22 are indicated by thick lines.

[0024] In this embodiment, the cells 10 are used in a state of being stacked in the vertical direction. The refrigerant flows vertically from the bottom to the top in the first passages 21. The refrigerant flowing in the first passages 21 flows upward, and part of the refrigerant passes between adjacent cells 10 and flows into the second passages 22. The refrigerant that has flowed into the second passages 22 flows vertically from the bottom to the top in the second passages 22.

[0025] As the refrigerant, a cooling liquid such as cooling oil can be suitably applied. A drive source (such as a pump) for flowing the refrigerant, a valve for flowing the refrigerant in a desired direction, and a sealing structure and a sealing device for preventing leakage of the refrigerant can be appropriately adopted from known technologies, and therefore a description thereof will be omitted. In short, it is sufficient to configure the refrigerant to flow in the region where the buffer sheet 100 is arranged between the adjacent cells 10.

[0026] <Cushioning sheet> In particular, the buffer sheet 100 according to this embodiment will be described with reference to Figures 2 and 3. The buffer sheet 100 according to this embodiment is used in such a way that the refrigerant flows in the vertical direction (from top to bottom or from bottom to top) in Figure 2 when incorporated in the battery 1. This buffer sheet 100 includes a flat plate portion 110, a plurality of protruding portions 120 protruding from both sides of the flat plate portion 110, and a plurality of through holes 130 provided so as to penetrate both sides of the flat plate portion 110.

[0027] As shown in the figure, the multiple protrusions 120 are aligned in a plurality of rows along the direction in which the refrigerant flows. In the example shown, the protrusions 120 are aligned in groups of four along the direction in which the refrigerant flows, and are arranged in eleven rows. The through holes 130 extend along the direction in which the refrigerant flows, and are arranged in a plurality of rows. In the example shown, the through holes 130 are arranged in ten rows.

[0028] <Advantages of the battery and the cushioning sheet according to the present embodiment> According to this embodiment, since a plurality of through holes 130 are provided in the buffer sheet 100, the refrigerant can travel between a flow path formed on one surface side of the flat plate portion 110 and a flow path formed on the other surface side. In addition, the amount of bending of the flat plate portion 110 can be suppressed by the amount of the plurality of through holes 130 provided.

[0029] In this embodiment, the protrusions 120 are arranged in a row along the direction in which the refrigerant flows. This makes it difficult for the protrusions 120 to impede the flow of the refrigerant.

[0030] The through holes 130 are arranged in a plurality of rows so as to extend in the direction in which the refrigerant flows. This makes it possible to suppress the difference in flow path area on both sides of the flat plate portion 110 caused by the bending of the flat plate portion 110. This point will be described with particular reference to FIG. 3(b). This figure shows the state of the buffer sheet 100 when a plurality of cells 10 are stacked vertically and a refrigerant flows between the cells 10. In this figure, the positions of the surfaces of the cells are indicated by dotted lines 11.

[0031] In this embodiment, by arranging the protruding parts 120 and the through holes 130 as described above, the flat plate part 110 is composed of an outer frame part along the four sides and a part connecting the protruding parts 120 arranged along the direction in which the refrigerant flows, as shown in Fig. 2. Therefore, since both sides of the part of the flat plate part 110 connecting the protruding parts 120 are made empty by the through holes 130, even if the part is deflected, the amount of deflection is small (see Fig. 3(b)). As a result, the difference in flow path area between both sides of the flat plate part 110 can be suppressed.

[0032] As described above, the difference in flow path area between both sides of the flat plate portion 110 can be suppressed, and coupled with the through holes 130 allowing the refrigerant to freely move between both sides of the flat plate portion 110, the occurrence of a temperature difference in the refrigerant flowing through both sides of the flat plate portion 110 can also be suppressed. This allows the cooling performance to be equalized on both sides of the flat plate portion 110, and a stable cooling effect can be obtained. Therefore, the combination of the application of an appropriate pressing force to the cells 10 by the buffer sheet 100 and the stable cooling effect can effectively suppress deterioration of the cells 10.

[0033] (others) In the above embodiment, the protrusion 120 is cylindrical, but the shape of the protrusion in the present invention is not particularly limited. An example of the shape of the protrusion will be described with reference to FIG. 4. In FIG. 4, a part near the protrusion is shown in a plan view. For example, as shown in FIG. 4(a), a triangular prism-shaped protrusion 120a can be adopted. The directions of the triangles may all face the same direction as shown on the left side of the figure, or may be arranged so that the directions are different as shown on the right side. In addition, as shown in FIG. 4(b), a protrusion 120b having an oval planar shape can be adopted. Furthermore, as shown in FIG. 4(c), a quadrangular prism-shaped protrusion 120c can be adopted. In this way, various shapes can be adopted for the protrusion. [Explanation of symbols]

[0034] 1:Battery 10: Cell 21:1st aisle 22:Second aisle 100: Cushioning sheet 110: Flat plate part 120,120a,120b,120c:Protrusion 130:Through hole

Claims

1. A plurality of cells; A plurality of buffer sheets each disposed between adjacent cells; a refrigerant passage for allowing a refrigerant to flow through a region between adjacent cells in which the buffer sheet is disposed; A battery comprising: The buffer sheet is A flat plate portion; A plurality of protruding portions protruding from both sides of the flat plate portion; A plurality of through holes provided to penetrate both surfaces of the flat plate portion; A battery comprising:

2. The battery according to claim 1 , wherein the plurality of protrusions are aligned in a direction in which the coolant flows and are arranged in a plurality of rows.

3. 3. The battery according to claim 1, wherein the through holes are arranged in a plurality of rows so as to extend in a direction in which the coolant flows.

4. A buffer sheet disposed between adjacent cells in a battery configured to allow a coolant to flow between the adjacent cells, comprising: A flat plate portion; A plurality of protruding portions protruding from both sides of the flat plate portion; A plurality of through holes provided to penetrate both surfaces of the flat plate portion; A cushioning sheet comprising:

5. The buffer sheet according to claim 4 , wherein the plurality of protrusions are aligned in a direction in which the refrigerant flows and are arranged in a plurality of rows.

6. 6. The buffer sheet according to claim 4, wherein the through holes are arranged in a plurality of rows so as to extend in the direction in which the refrigerant flows.

Images