Buffer sheet

Abstract

To provide a buffer sheet capable of generating reaction force stably.SOLUTION: A buffer sheet 100 made of an elastic body, comprises a flat plate part 110, and a plurality of protrusion parts 120 that protrude from the flat plate part 110 and the inside of which is a cavity that opens to the opposite side of a protrusion direction. At least one of an inner surface and an outer surface of the protrusion part 120 is provided with a groove that serves as a deformation starting point when the protrusion part 120 is compressed and deformed.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, a buffer sheet is known that is arranged between a base and a load to suppress the transmission of vibration to the load placed on the base. This buffer sheet is made of an elastic material, and generates an elastic reaction force against the load applied from the load. Taking advantage of such properties, buffer sheets have been used in recent years to suppress the deterioration of cells such as lithium-ion batteries. For example, lithium-ion batteries have a problem with the generation of needle-like crystals (dendrites) of lithium metal that occur when the batteries are repeatedly charged and discharged. If these crystals continue to grow, they will 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 causes variation in performance and also 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-mentioned crystals in lithium-ion batteries.

[0003] In order to generate a desired reaction force, the buffer sheet needs to be compressed so that the amount of compression of the buffer sheet falls within a predetermined range. In the case of a flat buffer sheet, the reaction force increases rapidly as the amount of compression increases. Therefore, a technique of providing multiple protrusions is known, but even in this case, there is a limit to suppressing the rapid increase in reaction force that occurs with an increase in the amount of compression, so a technique of making the inside of the protrusions hollow is also known. However, in such a technique, the protrusions may not maintain the desired posture when compressed, and there is a risk that the desired reaction force will not be generated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7165760 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a buffer sheet capable of generating a stable reaction force. [Means for solving the problem]

[0006] The present invention employs the following means to solve the above problems.

[0007] That is, the buffer sheet of the present invention is A flat plate portion; A plurality of protruding portions protruding from the flat plate portion, the interior of each of which is a cavity that opens to a side opposite to a protruding direction; A cushioning sheet made of an elastic body comprising: At least one of the inner surface and the outer surface of the protrusion is provided with a groove that serves as a deformation starting point when the protrusion is compressed and deformed.

[0008] According to the present invention, when the protrusion is compressed and deformed, the deformation starts from the groove, so that it is possible to stabilize the posture when the protrusion is compressed and deformed.

[0009] The protrusion is A pair of flat plate-like portions, the distance between opposing surfaces of which decreases toward the tip in the protruding direction; A curved plate-like portion connecting the tips of the pair of flat plate-like portions; Equipped with The groove may be provided in the flat portion.

[0010] By adopting such a configuration, it is possible to more reliably stabilize the posture of the protruding portion when it is deformed by compression.

[0011] The protruding portion includes a side portion formed of two pairs of flat plate-like portions in which the distance between opposing surfaces decreases toward the tip in the protruding direction, and a curved plate-like portion connecting all of the tips of the two pairs of flat plate-like portions, It is also preferable that the groove is provided around the entire periphery of the side surface portion.

[0012] By adopting such a configuration, it is possible to more reliably stabilize the posture of the protruding portion when it is deformed by compression.

[0013] The groove may be provided so as to extend parallel to the flat plate portion.

[0014] This makes it possible to prevent the protruding portion from tilting relative to the flat plate portion when the protruding portion is compressed.

[0015] The groove may be provided on the inner surface within a range extending from a center position of the length of the flat portion in the protruding direction to the flat portion.

[0016] The groove may be provided on the outer surface within a range toward the flat portion relative to a center position of the length of the flat portion in the protruding direction.

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

[0018] As described above, according to the present invention, a reaction force can be generated stably. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing an application example of the buffer sheet according to the first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the buffer sheet according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a side view of the buffer sheet according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view of the buffer sheet according to the first embodiment of the present invention. [Diagram 5] FIG. 5 is an explanatory diagram of a protrusion according to the first embodiment of the present invention. [Figure 6] FIG. 6 is an explanatory diagram of a protrusion according to the first embodiment of the present invention. [Figure 7] FIG. 7 is an explanatory diagram of a protrusion according to the first embodiment of the present invention. [Figure 8] FIG. 8 is an explanatory diagram of a protrusion according to the first embodiment of the present invention. [Figure 9] FIG. 9 is an explanatory diagram of a protrusion according to the second embodiment of the present invention. [Figure 10] FIG. 10 is an explanatory diagram of a protrusion according to the second embodiment of the present invention. [Figure 11] FIG. 11 is an explanatory diagram of a protrusion according to the second embodiment of the present invention. [Figure 12] FIG. 12 is an external view of a buffer sheet according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following describes in detail the embodiments and examples of the present invention with reference to the drawings. However, the dimensions, materials, shapes, relative positions, and the like of the components described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

[0021] (Embodiment 1) The buffer sheet according to the first embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig. 1 is a schematic diagram showing an application example of the buffer sheet according to the first embodiment of the present invention. Fig. 2 is a plan view of the buffer sheet according to the first embodiment of the present invention. Fig. 3 is a side view of the buffer sheet according to the first embodiment of the present invention, where (a) is a view seen in the V1 direction in Fig. 2 and (b) is a view seen in the V2 direction in Fig. 2. Fig. 4 is a schematic cross-sectional view of the buffer sheet according to the first embodiment of the present invention, where (a) is a cross-sectional view taken along the line A1-A1 in Fig. 2 and (b) is a cross-sectional view taken along the line A2-A2 in Fig. 2. Fig. 5 is an explanatory view of a protrusion according to the first embodiment of the present invention.

[0022] <Examples of cushioning sheet applications> An application example of the buffer sheet 100 will be described with reference to FIG. 1. FIG. 1(a) shows a case where the buffer sheet 100 is applied to a battery 10. The battery 10 is composed of a cell stack in which a plurality of unit cells 210 are stacked. The cell stack is compressed by a pair of clamping plates 221 and 222. The pair of clamping plates 221 and 222 are fastened by a bolt 231 and a nut 232, so that a predetermined compressive force acts on the cell stack. In the battery 10 according to this embodiment, the buffer sheet 100 is provided between the clamping plate 221 and the cell stack, between adjacent unit cells 210, and between the cell stack and the clamping plate 222. As a result, even if the unit cells 210 expand and contract due to charging and discharging, an appropriate pressing force can be applied to each unit cell 210. This can suppress deterioration of the battery 10 and extend the life of the battery 10.

[0023] 1(b) shows a configuration in which a buffer sheet 100 is provided between the base 310 and the load 320. As a result, even if the base 310 vibrates, the transmission of the vibration to the load 320 is suppressed, and even if the base 310 receives an impact, the impact is absorbed by the buffer sheet 100, thereby suppressing the impact on the load 320.

[0024] <Cushioning sheet> The buffer sheet 100 according to this embodiment will be described with reference to Figs. 2 to 5. The buffer sheet 100 is made of an elastic body, and is made of an elastomer material (e.g., rubber). The buffer sheet 100 includes a flat plate portion 110 and a plurality of protruding portions 120 protruding from the flat plate portion 110. In the example shown in Fig. 2, the plurality of protruding portions 120 are provided in six locations so as to be aligned in a row at equal intervals, but the arrangement and number of the protruding portions 120 are not particularly limited and may be set according to the overall dimensions and shape of the buffer sheet 100 and the environment in which it is used. The protruding portions 120 are configured so that their interiors are hollow and open to the opposite side to the protruding direction (see hollow portion 120X in Fig. 4).

[0025] In the case of the buffer sheet 100 configured as above, depending on the usage environment, the opening in the cavity 120X may be blocked by a member arranged on the opposite side to the protruding direction of the protruding portion 120, and the cavity 120X may become a sealed space. In this case, when the protruding portion 120 is compressed, the air in the cavity cannot escape to the outside, and the reaction force becomes higher than expected. Therefore, depending on the usage environment, it is preferable to provide a communication groove 124 for connecting the space of the cavity 120X to the outside space on the bottom surface of the flat plate portion 110. This can prevent the cavity 120X from becoming a sealed space. However, if a passage for releasing the air in the cavity is formed on the member arranged on the opposite side to the protruding direction of the protruding portion 120, it is not necessary to provide the above-mentioned communication groove 124. Also, even if there is no problem even if the cavity 120X becomes a sealed space, it is not necessary to provide the communication groove 124.

[0026] The protruding portion 120 according to the present embodiment has a side portion made up of two pairs of flat plate-like portions in which the distance between the opposing surfaces becomes shorter toward the tip in the protruding direction, and the tips of the two pairs of flat plate-like portions are completely connected to each other. The side surface portion is composed of a pair of flat plate portions 121a, 121b extending in the longitudinal direction, and a pair of flat plate portions 122a, 122b extending in the lateral direction.

[0027] In the buffer sheet 100 according to this embodiment, at least one of the inner surface and the outer surface of the protruding portion 120 is provided with a groove that becomes a deformation starting point when the protruding portion 120 is compressed and deformed. This groove is preferably provided around the entire circumference of the side surface of the protruding portion 120. That is, it is preferable that the groove is provided in the pair of flat plate portions 121a, 121b and the pair of flat plate portions 122a, 122b. This point will be described in more detail with reference to FIG. 5. Note that the above-mentioned grooves are omitted in FIGS. 2 to 4.

[0028] 5(a) and (b) show cross-sectional views of the case where grooves 125 are provided on the inner surface of protruding portion 120. FIG. 5(a) corresponds to a cross-sectional view of protruding portion 120 in FIG. 4(a) in an enlarged scale, and FIG. 5(b) corresponds to a view of grooves 125 in FIG. 4(b). As shown in these figures, grooves 125 are provided around the entire inner surface of the side surface of protruding portion 120. That is, grooves 125 are provided so as to be continuously connected to the inner surfaces of flat plate-like portions 121a, 121b, 122a, and 122b. Grooves 125 are provided so as to extend parallel to flat plate portion 110.

[0029] 5(c) and (d) show side views in the case where grooves 126 are provided on the outer surface of protrusion 120. FIG. 5(c) corresponds to a side view in which the protrusion 120 in FIG. 3(a) is enlarged, and FIG. 5(d) corresponds to a view in which grooves 126 are clearly shown in FIG. 3(b). As shown in these figures, grooves 126 are provided around the entire outer surface of the side surface of protrusion 120. That is, grooves 126 are provided so as to be continuously connected to the outer surfaces of flat portions 121a, 121b, 122a, and 122b. Grooves 126 are provided so as to extend parallel to flat portion 110.

[0030] <Advantages of the cushioning sheet according to this embodiment> According to the buffer sheet 100 of this embodiment, when the protrusion 120 is compressed and deformed, the deformation starts from the grooves 125 and 126. Therefore, it is possible to stabilize the posture of the protrusion 120 when it is deformed by compression. That is, in the case of a protrusion without a groove, the strength of each part of the protrusion is almost equal, so the part where the deformation starts may differ depending on the dimensional tolerance of the protrusion and the state when the protrusion is compressed, and the posture when it is compressed may become unstable. In contrast, if the grooves 125 and 126 are provided as in this embodiment, the strength of the part where the grooves 125 and 126 are provided is lower than the other parts, so when the protrusion 120 is compressed, the deformation starts from the grooves 125 and 126. Therefore, it is possible to stabilize the posture of the protrusion 120 when it is deformed by compression.

[0031] In this embodiment, the grooves 125 and 126 are provided in the flat plate portions 121a, 121b, 122a, and 122b, rather than in the curved plate portion 123. This makes it possible to more reliably stabilize the posture of the protruding portion 120 when it is deformed by compression. The reason for this will be explained in the following examples.

[0032] Moreover, in this embodiment, the grooves 125, 126 are provided so as to extend parallel to the flat plate portion 110. This makes it possible to prevent the protruding portion 120 from tilting relative to the flat plate portion 110 when the protruding portion 120 is compressed. That is, in the case of the application example of the buffer sheet 100 described with reference to FIG. 1, it is desirable that the protruding portion 120 is compressed perpendicular to the flat plate portion 110. Therefore, as described above, by providing the grooves 125, 126 so as to extend parallel to the flat plate portion 110, it is possible to prevent the protruding portion 120 from tilting relative to the flat plate portion 110 when the protruding portion 120 is compressed. Note that, depending on the application example of the buffer sheet 100, However, if it is desired that the protrusion 120 be compressed so as to be inclined relative to the flat plate portion 110, a configuration in which the groove is inclined relative to the flat plate portion 110 can also be adopted.

[0033] Here, the following two points are particularly required as functions of the protruding portion 120.

[0034] The first point is that, as described above, the posture of the protruding portion 120 when compressed is stable. When a compressive force acts on the protruding portion 120 in an ideal direction (in the above example, a direction perpendicular to the flat plate portion 110), the posture of the protruding portion 120 can be stabilized. However, depending on the usage environment, the compressive force acting on the protruding portion 120 may deviate from the ideal direction. Therefore, even in such cases, it is desirable to make it possible to stabilize the posture of the protruding portion 120 in the compressed state.

[0035] In addition, the compressive force acting on the protrusion 120 varies depending on the usage environment. In an environment where the change in the amount of compression is large, if the reaction force when the protrusion 120 is compressed changes significantly, the function of the buffer sheet 100 may not be fully exerted. Therefore, the second point is that it is desirable that the change in the reaction force of the protrusion 120 is small in response to the change in the amount of compression of the protrusion 120. If this change is small, the buffer sheet 100 can be applied in different usage environments, and versatility is also increased.

[0036] The above two points depend on various parameters. However, the inventors of the present application have found that the above two points are highly dependent on the arrangement positions of the grooves 125 and 126. Therefore, verification results obtained when the arrangement positions of the grooves 125 and 126 are different will be described with reference to the following Examples 1 and 2. Example 1 shows a configuration in which the groove 125 is provided on the inner surface of the protruding portion 120, and Example 2 shows a configuration in which the groove 126 is provided on the outer surface of the protruding portion 120.

[0037] <Example 1> The configuration of the protrusion according to the first embodiment of the present invention will be described with reference to Fig. 6 to Fig. 8. Fig. 6 to Fig. 8 are explanatory diagrams of the protrusion according to the first embodiment of the present invention. Fig. 6 is a schematic cross-sectional view showing the state of the protrusion when no compressive force is applied. Fig. 7 is a schematic cross-sectional view showing the state of the protrusion when a compressive force is applied obliquely. Fig. 8 is a graph showing the relationship between the compression amount of the protrusion and the reaction force.

[0038] 6(a) and (b) show a configuration in which a groove is provided on the inner surface of the curved plate-like portion 123 in the protruding portion 120 described in the above embodiment. Hereinafter, these are referred to as Example 1 and Example 2, respectively. In Example 1, a linear groove 125a is provided at the very tip (upper end in the figure) of the inner surface of the curved plate-like portion 123 so as to run along the pair of flat plate-like portions 121a and 121b. In Example 2, an annular groove 125b is provided near the base (lower end in the figure) of the inner surface of the curved plate-like portion 123 so as to run along the pair of flat plate-like portions 121a and 121b and the pair of flat plate-like portions 122a and 122b.

[0039] 6(c), (d), (e), (f), and (g) show a configuration in which the grooves 125 are provided so as to be continuously connected to the inner surfaces of the flat-plate portions 121a, 121b, 122a, and 122b in the protruding portion 120 described in the above embodiment. Hereinafter, these are referred to as Example 3, Example 4, Example 5, Example 6, and Example 7, respectively. In Example 3, a groove 125c is provided on the inner surface of the flat-plate portion near the tip (upper end in the figure) in the protruding direction of the flat-plate portion. In Example 4, a groove 125d is provided on the inner surface of the flat-plate portion at a position between the center position of the length of the flat-plate portion in the protruding direction and the tip in the protruding direction. In Example 5, a groove 125e is provided on the inner surface of the flat-plate portion at the center position of the length of the flat-plate portion in the protruding direction. In Example 6, a groove 125c is provided on the inner surface of the flat-plate portion near the center position of the length of the flat-plate portion in the protruding direction and the tip in the protruding direction of the flat-plate portion. A groove 125f is provided at a position between the boundary with the flat plate portion 110. In Example 7, a groove 125g is provided on the inner surface of the flat plate portion near the boundary with the flat plate portion 110.

[0040] FIG. 7 shows the state of the protrusion 120 when a compressive force acts obliquely on the protrusion 120. FIG. 7(a) shows the state of the protrusion 120 when the groove 125 is not provided as a reference example. FIG. 7(b) shows the case of Example 2, FIG. 7(c) shows the case of Example 3, FIG. 7(d) shows the case of Example 4, FIG. 7(e) shows the case of Example 5, and FIG. 7(f) shows the case of Example 7. From these figures, when the groove 125 is not provided and when the groove 125 is provided on the inner surface of the curved plate-like portion 123, when a compressive force acts obliquely, the protrusion 120 is greatly deformed and its posture becomes unstable. In addition, in the case of Example 2, it is understood that the protrusion 120 is in a state of being slightly buckled. In the other examples, it is understood that even if a compressive force acts obliquely, the protrusion 120 can be prevented from being greatly deformed and the posture of the protrusion 120 can be stabilized. Although the case of Example 1 is not particularly illustrated, it goes without saying that the same behavior as in FIG. 7(a)(b) is exhibited. Also, although not specifically shown in the figure, Example 6 is in a state intermediate between the state in Figure 7(e) and the state in Figure 7(f). From the above, it can be seen that, of the two desired functions of the protruding portion 120 described above, the first of these can be met by providing groove 125 in the flat portion, but it is better to avoid a position near the tip of the flat portion in the protruding direction.

[0041] FIG. 8 is a graph showing the relationship between the compression amount of the protrusion and the reaction force. Graphs L5a, L5b, L5c, L5d, L5e, L5f, and L5g in the figure are graphs for Examples 1, 2, 3, 4, 5, 6, and 7, respectively. Graph L5h is a graph of a configuration (reference example) in which the groove 125 is not provided in the protrusion 120. From these graphs, it can be seen that the same relationship is shown in Examples 1 and 2. It was also confirmed that the reference example in which no groove is provided also shows a similar relationship to Examples 1 and 2. It can also be seen that the range of the compression amount in which the reaction force does not change much can be widened, particularly in Examples 5, 6, and 7. From the above, it can be seen that, regarding the second of the two points desired as the functions of the protrusion 120 described above, the groove 125 may be provided within a range from the center position of the length in the protruding direction of the flat plate-shaped portion to the flat plate portion 110.

[0042] <Example 2> The configuration of the protrusion according to the second embodiment of the present invention will be described with reference to Figs. 9 to 11. Figs. 9 to 11 are explanatory diagrams of the protrusion according to the second embodiment of the present invention. Fig. 9 is a schematic cross-sectional view showing the state of the protrusion when no compressive force is applied. Fig. 10 is a schematic cross-sectional view showing the state of the protrusion when a compressive force is applied obliquely. Fig. 11 is a graph showing the relationship between the compression amount of the protrusion and the reaction force.

[0043] 9(a) and (b) show the configuration of the protruding portion 120 described in the above embodiment in which a groove is provided on the outer surface of the curved plate-like portion 123. Hereinafter, these are referred to as Example 1 and Example 2, respectively. In Example 1, a linear groove 126a is provided at the very tip (upper end in the figure) of the outer surface of the curved plate-like portion 123 so as to run along the pair of flat plate-like portions 121a and 121b. In Example 2, an annular groove 126b is provided near the base (lower end in the figure) of the outer surface of the curved plate-like portion 123 so as to run along the pair of flat plate-like portions 121a and 121b and the pair of flat plate-like portions 122a and 122b.

[0044] 9(c), (d), (e), (f), and (g) show a configuration in which grooves 126 are provided so as to be continuously connected on the outer surfaces of flat portions 121a, 121b, 122a, and 122b in the protruding portion 120 described in the above embodiment. Hereinafter, these are referred to as Example 3, Example 4, Example 5, Example 6, and Example 7, respectively. In Example 3, groove 126c is provided on the outer surface of the flat portion near the tip (upper end in the figure) of the flat portion in the protruding direction. In Example 4, groove 126c is provided on the outer surface of the flat portion between the center position of the length of the flat portion in the protruding direction and the tip in the protruding direction. In Example 5, groove 126e is provided at the center of the length of the flat plate portion in the protruding direction on the outer surface of the flat plate portion. In Example 6, groove 126f is provided at a position between the center of the length of the flat plate portion in the protruding direction on the outer surface of the flat plate portion and the boundary with flat plate portion 110. In Example 7, groove 126g is provided at the outer surface of the flat plate portion near the boundary with flat plate portion 110.

[0045] FIG. 10 shows the state of the protrusion 120 when a compressive force acts obliquely on the protrusion 120. FIG. 10(a) shows the state of the protrusion 120 when the groove 126 is not provided as a reference example. FIG. 10(b) shows the case of Example 2, FIG. 10(c) shows the case of Example 3, FIG. 10(d) shows the case of Example 4, FIG. 10(e) shows the case of Example 5, FIG. 10(f) shows the case of Example 6, and FIG. 10(g) shows the case of Example 7. From these figures, when the groove 126 is not provided and when the groove 126 is provided on the inner surface of the curved plate-like portion 123, when a compressive force acts obliquely, the protrusion 120 is greatly deformed and the posture becomes unstable. In addition, in the case of Example 5, it is seen that a state in which slight buckling occurs occurs. In the other examples, it is seen that even if a compressive force acts obliquely, the protrusion 120 can be prevented from being greatly deformed and the posture of the protrusion 120 can be stabilized. 10(a)(b)。As described above, it is understood that, of the two desired functions of the protrusion 120 described above, the first function can be satisfied by providing the groove 126 in the flat portion, but it is better to avoid the center position of the length of the protrusion direction of the flat portion.

[0046] FIG. 11 is a graph showing the relationship between the compression amount of the protrusion and the reaction force. Graphs L6a, L6b, L6c, L6d, L6e, L6f, and L6g in the figure are graphs for Examples 1, 2, 3, 4, 5, 6, and 7, respectively. Graph L6h is a graph of a configuration (reference example) in which the groove 126 is not provided in the protrusion 120. From these graphs, it can be seen that the same relationship is shown in Examples 1 and 2. It was also confirmed that the reference example in which no groove is provided also shows a similar relationship to Examples 1 and 2. It can also be seen that the range of the compression amount in which the reaction force hardly changes can be widened, particularly in Examples 6 and 7. From the above, it can be seen that, regarding the second of the two points desired as the functions of the protrusion 120 described above, the groove 126 may be provided within a range on the flat plate portion 110 side from the center position of the length in the protruding direction of the flat plate portion.

[0047] (Embodiment 2) The buffer sheet according to the first embodiment of the present invention will be described with reference to Fig. 12. Fig. 12 is an external view of the buffer sheet according to the second embodiment of the present invention, where (a) is a plan view and (b) is a side view (view seen in the V3 direction in (a)).

[0048] The buffer sheet 100A according to this embodiment can also be applied to the battery 10 or placed between the base 310 and the load 320, as described with reference to FIG.

[0049] The buffer sheet 100A according to this embodiment is also made of an elastic body, and is made of an elastomer material (e.g., rubber). This buffer sheet 100A includes a flat plate portion 110A and a plurality of protruding portions 120A protruding from the flat plate portion 110A. In the illustrated example, the plurality of protruding portions 120A are provided in six places so as to be aligned in a row at equal intervals, but the arrangement and number of the protruding portions 120A are not particularly limited and may be set according to the overall dimensions and shape of the buffer sheet 100A and the usage environment. These protruding portions 120A are configured so that their interiors are cavities that open to the opposite side to the protruding direction and to the side. In the case of the buffer sheet 100A according to this embodiment, the internal cavities of the protruding portions 120A are also open to the side, so that the cavities do not become sealed spaces in the above-mentioned application examples.

[0050] The protrusion 120A according to this embodiment is composed of a pair of flat plate portions 121Aa, 121Ab whose opposing surfaces have a distance between them that decreases toward the tip in the protruding direction, and a curved plate portion 123A connecting the tips of the pair of flat plate portions 121Aa, 121Ab.

[0051] In the buffer sheet 100A configured as described above, as in the first embodiment, at least one of the inner surface and the outer surface of the protruding portion 120A may be provided with a groove that serves as a deformation starting point when the protruding portion 120A is compressed and deformed. In the case of this embodiment, at least one of the inner surface and the outer surface of the pair of flat plate-like portions 121Aa, 121Ab may be provided with a linear groove. The configuration and arrangement of the groove are as described in the first and second embodiments, and therefore will not be described here.

[0052] By adopting the above-mentioned configuration, the same effects as those of the first embodiment and the first and second examples can be obtained.

[0053] (others) In the above embodiments, the grooves that become the deformation starting points when the protrusion is compressed and deformed are provided only on the inner surface or the outer surface of the protrusion, but a configuration in which grooves are provided on both the inner surface and the outer surface can be adopted. Also, in the above embodiments, the case where one groove is provided on the inner surface and the case where one groove is provided on the outer surface are shown, but two or more grooves may be provided on the inner surface or two or more grooves may be provided on the outer surface. [Explanation of symbols]

[0054] 10:Battery 100, 100A: Buffer sheet 110,110A: Flat plate part 120,120A: Protrusion 120X: Cavity 121a, 121b, 122a, 122b, 121Aa, 121Ab: Flat part 123, 123A: Curved plate-shaped part 124:Communication groove 125,125a,125b,125c,125d,125e,125f,125g,126,126a,126b,126c,126d,126e,126f,126g:Groove 210: Single cell 221,222: Holding plate 231: Bolt 232: Nut 310: Pedestal 320: Cargo

Claims

1. A flat plate portion; A plurality of protruding portions protruding from the flat plate portion, the interior of each of which is a cavity that opens to a side opposite to a protruding direction; A cushioning sheet made of an elastic body comprising: A cushioning sheet, characterized in that at least one of the inner and outer surfaces of the protrusion is provided with a groove that serves as a deformation starting point when the protrusion is compressed and deformed.

2. The protrusion is A pair of flat plate-like portions, the distance between opposing surfaces of which decreases toward the tip in the protruding direction; A curved plate-like portion connecting the tips of the pair of flat plate-like portions; Equipped with 2. The cushioning sheet according to claim 1, wherein the groove is provided in the flat portion.

3. The protruding portion includes a side portion formed of two pairs of flat plate-like portions in which the distance between opposing surfaces decreases toward the tip in the protruding direction, and a curved plate-like portion connecting all of the tips of the two pairs of flat plate-like portions, 2. The cushioning sheet according to claim 1, wherein the groove is provided around the entire periphery of the side surface.

4. 4. The buffer sheet according to claim 2, wherein the groove is provided so as to extend parallel to the flat plate portion.

5. 5. The buffer sheet according to claim 4, wherein the groove is provided on the inner surface within a range extending from a center position of the length of the flat portion in the protruding direction to the flat portion.

6. The buffer sheet according to claim 4, wherein the groove is provided on the outer surface within a range toward the flat portion from a center position of the length of the flat portion in the protruding direction.

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