Cushioning sheet, battery, and base

Abstract

To provide a cushioning sheet that can suppress the occurrence of buckling in the protruding portion. [Solution] The invention is characterized by comprising a flat plate portion 110, a plurality of first protrusions 121 that protrude from the flat plate portion 110 and extend linearly in a first direction when viewed perpendicular to the plane of the flat plate portion 110, and a plurality of second protrusions 122 that protrude from the flat plate portion 110 and extend linearly in a second direction different from the first direction when viewed perpendicular to the plane of the flat plate portion 110.

Description

Technical Field

[0001] The present invention relates to a buffer sheet, a battery, and a pedestal.

Background Art

[0002] Conventionally, in order to suppress vibration transmission to a load placed on a pedestal, a buffer sheet disposed between the pedestal and the load is known. This buffer sheet is composed of an elastic body, and an elastic repulsive force is generated against the load acting from the load. Utilizing such properties, in recent years, a buffer sheet has been used to suppress deterioration of cells such as lithium-ion batteries. For example, in a lithium-ion battery, the generation of needle-like crystals (dendrites) of lithium metal that occur when charging and discharging are repeated has been a problem. If this crystal continues to grow, it will cause a short circuit between the positive electrode and the negative electrode. In the case of all-solid-state batteries, it is known that variations in surface pressure due to expansion and contraction result in variations in performance and also affect the lifespan. Therefore, measures have been taken to suppress the expansion of the cell by pressing the cell with an appropriate force or to mechanically suppress the growth of the above-mentioned crystals in a lithium-ion battery.

[0003] In the buffer sheet, in order to generate a desired reaction force, it is necessary to compress the buffer sheet so that the compression amount of the buffer sheet falls within a predetermined range. In the case of a flat buffer sheet, as the compression amount increases, the reaction force rapidly increases. Therefore, a technique of providing a plurality of protrusions is known, but even in this case, there is a limit to suppressing the rapid increase in the reaction force accompanying the increase in the compression amount, so a technique of making the inside of the protrusion hollow is also known. Referring to FIGS. 7 and 8, a buffer sheet according to the prior art will be described. FIG. 7 is a schematic view of a buffer sheet according to the prior art, (a) is a plan view of the buffer sheet, and (b) is a cross-sectional view taken along line BB in (a). FIG. 8 is a graph showing the relationship between the compression amount and the reaction force in the buffer sheet.

[0004] The conventional cushioning sheet 500 has a flat plate portion 510 and a plurality of protruding portions 520 that extend in a straight line from the flat plate portion 510, when viewed perpendicular to the plane of the flat plate portion 510, arranged in parallel. These protruding portions 520 are provided with a cavity portion 520X that opens on the opposite side from the direction of protrusion.

[0005] In Figure 8, graph L1 shows the case where there is no cavity in the protrusion, and graph L2 shows the case where a cavity 520X is provided in the protrusion 520. As shown in the figure, in order to obtain the desired reaction force range F, the amount of compression when there is no cavity in the protrusion must satisfy range W1, and the amount of compression when a cavity 520X is provided in the protrusion 520 must satisfy range W2. As can be seen from Figure 8, W2 > W1, and the latter has a wider range of operating conditions.

[0006] However, when the cushioning sheet 500 is compressed, depending on the direction of the load acting on the cushioning sheet 500, the protrusions 520 may collapse and buckle. That is, as shown in Figure 7, if the direction P of the load acting on the cushioning sheet 500 is oblique to the surface of the cushioning sheet 500 and perpendicular to the direction in which the protrusions 520 extend, multiple protrusions 520 become uniformly prone to collapsing. In Figure 8, graph L3 shows the case where buckling occurs in the protrusions 520. In this case, although the desired reaction force is obtained in the compression range W3, the desired reaction force is not obtained in the compression range W20 among the assumed usage conditions.

[0007] Furthermore, problems such as the protruding portion collapsing and buckling can also occur in cushioning sheets that have protruding portions without a hollow space. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2020 / 166357 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention provides a cushioning sheet, a battery, and a base capable of suppressing buckling of protruding parts. [Means for solving the problem]

[0010] To solve the above problems, the present invention employs the following means.

[0011] The cushioning sheet of the present invention is A cushioning sheet made of an elastic material, Flat section and A plurality of first protrusions extend linearly in a first direction when viewed in a direction perpendicular to the plane of the flat plate, A plurality of second protrusions extend linearly from the flat plate portion and, when viewed perpendicular to the plane of the flat plate portion, in a second direction different from the first direction, It is characterized by having the following features.

[0012] According to the present invention, even if the direction of the load acting on the cushioning sheet is oblique to the surface of the cushioning sheet and perpendicular to the direction in which the first protrusion extends, the second protrusion will not tip over, thereby preventing the first protrusion from tipping over.

[0013] The first and second protrusions may be provided with cavities that open on the opposite side of the protrusion direction.

[0014] The first and second directions should be orthogonal.

[0015] The battery of the present invention A cell stack in which multiple single cells are stacked, A pair of clamping plates for compressing the cell stack, A battery equipped with, The cushioning sheet is provided between at least one of the pair of clamping plates and the cell stack.

[0016] Further, the battery of the present invention includes a cell stack in which a plurality of single cells are stacked, and a pair of clamping plates for compressing the cell stack, and is a battery characterized in that the above buffer sheet is provided between adjacent single cells.

[0017] The pedestal of the present invention includes a pedestal body, and the above buffer sheet provided at a position on the pedestal body where a loaded object is loaded, and is characterized by comprising the same.

[0018] In addition, the above configurations can be adopted in combination as much as possible.

Advantages of the Invention

[0019] As described above, according to the present invention, the occurrence of buckling of the protrusion can be suppressed.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a schematic view showing an application example of a buffer sheet according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partial plan view of a buffer sheet according to an embodiment of the present invention. [Figure 3] FIG. 3 is a partial side view of a buffer sheet according to an embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view of a buffer sheet according to an embodiment of the present invention. [Figure 5] FIG. 5 is a plan view showing an arrangement example of protrusions in a buffer sheet according to an embodiment of the present invention. [Figure 6] FIG. 6 is a schematic view showing a modified example of a buffer sheet. [Figure 7] FIG. 7 is a schematic view of a buffer sheet according to the prior art. [Figure 8] FIG. 8 is a graph showing the relationship between the compression amount and the reaction force in a buffer sheet. [Modes for carrying out the invention]

[0021] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, unless otherwise specifically stated, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments are not intended to limit the scope of this invention to those components alone.

[0022] (Examples) Referring to Figures 1 to 5, the cushioning sheet, battery, and base according to embodiments of the present invention will be described. Figure 1 is a schematic diagram showing an application example of the cushioning sheet according to embodiments of the present invention. Figure 2 is a part of the plan view of the cushioning sheet according to embodiments of the present invention. Figure 3 is a part of the side view of the cushioning sheet according to embodiments of the present invention. Figure 4 is a schematic cross-sectional view of the cushioning sheet according to embodiments of the present invention, which is the AA cross-sectional view in Figure 2. Figure 5 is a plan view showing an example of the arrangement of protrusions in the cushioning sheet according to embodiments of the present invention.

[0023] <Examples of cushioning sheet applications> Referring to Figure 1, an example of the application of the cushioning sheet 100 will be described. Figure 1(a) shows the case when the cushioning sheet 100 is applied to a battery 10. The battery 10 is composed of a cell stack in which a plurality of single cells 210 are stacked. The cell stack is compressed by a pair of clamping plates 221 and 222. A predetermined compressive force is applied to the cell stack by fastening the pair of clamping plates 221 and 222 with bolts 231 and nuts 232. In the battery 10 according to this embodiment, the cushioning sheet 100 is provided between the clamping plate 221 and the cell stack. As a result, even if the single cells 210 expand and contract due to charging and discharging, an appropriate compressive force can be applied to each single cell 210. Therefore, deterioration of the battery 10 can be suppressed and the life of the battery 10 can be extended. The cushioning sheet 100 may be provided between the clamping plate 222 and the cell stack, or it may be provided both between the clamping plate 221 and the cell stack, and between the clamping plate 222 and the cell stack. Furthermore, as shown in the circled area in Figure 1(a), a configuration in which a buffer sheet 100 is provided between adjacent single cells 210 can also be adopted. The buffer sheet 100 may be provided not only between adjacent single cells 210, but also between the clamping plate and the cell stack as described above, or it may be provided only between adjacent single cells 210. When providing a buffer sheet 100 between adjacent single cells 210, it may be provided between all adjacent single cells 210, or it may be provided at one or several locations between specific adjacent single cells 210.

[0024] Figure 1(b) shows a configuration in which a cushioning sheet 100 is provided between the base 310 and the load 320. This suppresses the transmission of vibrations to the load 320 even if the base 310 vibrates, and also absorbs the impact of an impact on the base 310. This can suppress impacts on the load 320. Furthermore, the base can also be configured with a cushioning sheet 100 on the surface of the base body.

[0025] <Cushioning sheet> The cushioning sheet 100 according to this embodiment will be described with reference to Figures 2 to 5. The cushioning sheet 100 is made of an elastic material, specifically an elastomer material such as rubber. The cushioning sheet 100 comprises a flat plate portion 110 and a plurality of first protrusions 121 and second protrusions 122 that protrude from the flat plate portion 110. The plurality of first protrusions 121 are configured to extend linearly in a first direction when viewed in a direction perpendicular to the plane of the flat plate portion 110. The plurality of second protrusions are configured to extend linearly in a second direction different from the first direction when viewed in a direction perpendicular to the plane of the flat plate portion 110. In the example shown in Figures 2 and 3, the first and second directions are configured to be orthogonal.

[0026] Furthermore, the first protrusion 121 and the second protrusion 122 in this embodiment are provided with cavities 121X and 122X that open on the opposite side from the protrusion direction.

[0027] Figure 5 shows an example of the arrangement of multiple first protrusions 121 and second protrusions 122. Figures 5(a) and 5(b) show examples of the arrangement of multiple first protrusions 121 and second protrusions 122 in a configuration where the first direction and the second direction are orthogonal, respectively. In this invention, the first direction and the second direction do not necessarily have to be orthogonal. In other words, it is sufficient that the first protrusions 121 and the second protrusions are not parallel to each other.

[0028] In the example shown in Figure 5(c), the first direction in which the first projection 121a extends linearly and the second direction in which the second projection 122a extends linearly are configured to differ by 60°. Also in Figure 5(c), an example is shown in which there are multiple projections 123 that protrude from the flat plate portion 110 and extend linearly in directions different from the first and second directions when viewed perpendicular to the plane of the flat plate portion 110. Thus, the present invention also includes configurations in which projections different from the first projection 121 and the second projection 122 are provided.

[0029] <Advantages of the cushioning sheet according to this embodiment> The cushioning sheet 100 according to this embodiment includes a plurality of first protrusions 121 extending linearly in a first direction and a plurality of second protrusions 122 extending linearly in a second direction different from the first direction.

[0030] As a result, even if the direction of the load acting on the cushioning sheet 100 is oblique to the surface of the cushioning sheet 100 and perpendicular to the direction in which the first protrusion 121 extends (first direction), the second protrusion 122 will not tilt, thereby suppressing the tilting of the first protrusion 121. In other words, the second protrusion 122 is less likely to tilt under load in such a direction, and the frictional force between the member in contact with the first protrusion 121 and the second protrusion 122 and the contact surface of the cushioning sheet 100 is increased by the second protrusion 122. As a result, the force that would cause multiple first protrusions 121 to tilt uniformly is mitigated, and the tilting and buckling of the first protrusions 121 is suppressed. It goes without saying that even if the direction of the load acting on the cushioning sheet 100 is oblique to the surface of the cushioning sheet 100 and perpendicular to the direction in which the second protrusion 122 extends (second direction), the tilting and buckling of the second protrusion 122 is similarly suppressed. Therefore, it is possible to suppress problems such as the inability to obtain the desired reaction force due to buckling of the protrusion. In addition, since both the first protrusion 121 and the second protrusion 122 are configured to extend in a straight line and are provided independently of each other, it is possible to suppress an increase in the rebound force when compressed.

[0031] In this embodiment, the first direction and the second direction are configured to be orthogonal. When only protruding parts of a type are provided, the tilting of the first protruding part 121 and the second protruding part 122 can be effectively suppressed by configuring them so that the first direction and the second direction are perpendicular to each other.

[0032] Furthermore, in this embodiment, the first protrusion 121 and the second protrusion 122 are provided with cavities 121X and 122X that open on the opposite side from the protrusion direction. This allows for a wider range of compression amounts of the protrusions required to obtain a desired range of reaction force. Consequently, the range of operating conditions can be broadened. For example, in the example of the battery 10 shown in Figure 1(a), the allowable range of expansion and contraction amounts of the entire cell stack can be widened. Also, in the example shown in Figure 1(b), the range of applicable weights of the load 320 and vibration conditions in the operating environment can be broadened.

[0033] (others) In the case of the cushioning sheet 100 configured as described above, depending on the usage environment, the openings in the cavities 121X and 122X may be blocked by a member positioned on the opposite side of the protruding direction of the protruding part, causing the cavities 121X and 122X to become sealed spaces. In this case, when the protruding part is compressed, the air inside the cavity cannot escape, and the rebound force becomes higher than expected. Therefore, depending on the usage environment, for example, as shown in Figure 6(a) of the cushioning sheet 100A, a groove 111 is provided on the bottom surface of the flat plate portion 110A to connect the spaces of the cavities 121X and 122X with the external space. This prevents the cavities 121X and 122X from becoming sealed spaces.

[0034] Furthermore, the above embodiment shows a configuration in which a cavity is provided in the protruding portion. However, a configuration in which no cavity is provided in the protruding portion can also be adopted. That is, as shown in Figure 6(b) of the cushioning sheet 100B, by providing a plurality of first protruding portions 121B extending linearly in a first direction and a plurality of second protruding portions 122B extending linearly in a second direction different from the first direction, the collapse of these protruding portions can be suppressed. Figure 6(b) is a schematic cross-sectional view of a modified cushioning sheet. Except for the fact that no cavity is provided in the protruding portion, the configuration is the same as the above embodiment, and as with the above embodiment, various arrangements can be adopted for the arrangement of the first protruding portions 121B and the second protruding portions 122B, such as the arrangement example shown in Figure 5. In the cushioning sheet 100B configured in this way, the collapse and buckling of the first protruding portions 121B and the second protruding portions 122B is suppressed. [Explanation of Symbols]

[0035] 10:Battery 100, 100A, 100B: Cushioning sheet 110,110A: Flat plate part 111: Groove 121,121a,121B: 1st protrusion 121X: Cavity 122, 122a, 122B: 2nd protrusion 122X: Cavity 123:Protrusion 210: Single cell 221,222: Holding plate 231: Bolt 232: Nut 310: Pedestal 320: Cargo

Claims

1. A cushioning sheet made of an elastic material, Flat section and A plurality of first protrusions extend linearly in a first direction when viewed in a direction perpendicular to the plane of the flat plate, A plurality of second protrusions extend linearly in a second direction different from the first direction when viewed perpendicular to the plane of the flat plate, A cushioning sheet characterized by having the following features.

2. The cushioning sheet according to claim 1, characterized in that the first and second protrusions are provided with cavities that open on the opposite side from the direction of protrusion.

3. The cushioning sheet according to claim 1 or 2, characterized in that the first direction and the second direction are orthogonal.

4. A cell stack in which multiple single cells are stacked, A pair of clamping plates for compressing the cell stack, A battery equipped with, A battery characterized in that a buffer sheet according to claim 1 or 2 is provided between at least one of the pair of clamping plates and the cell stack.

5. A cell stack in which multiple single cells are stacked, A pair of clamping plates for compressing the cell stack, A battery equipped with, A battery characterized in that a buffer sheet according to claim 1 or 2 is provided between adjacent single cells.

6. The base body and A cushioning sheet according to claim 1 or 2, provided at the position on the base body where the load is placed, A base characterized by having the following features.

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