Battery buffer structure

Abstract

Provided is a battery cushioning structure that can improve cushioning function. A battery cushioning structure 100 that comprises a cushioning sheet 100 and interposing members 210, 220 that are to be arranged between the cushioning sheet 100 and battery-forming members is characterized in that the cushioning sheet 100 comprises protrusions 120a, 120b that protrude toward the interposing members 210, 220.

Description

Technical Field

[0001] The present invention relates to a buffer structure for a battery.

Background Art

[0002] In a battery configured as a cell stack in which a plurality of cells are stacked, the quality may deteriorate due to the expansion and contraction of the cells. For example, in the case of a lithium-ion battery, when the cell expands and contracts during charging and discharging, if no countermeasures are taken, the electrode particles will be loaded and crushed, shortening the battery life. In addition, in the case of a all-solid-state battery, it is known that variations in surface pressure accompanying expansion and contraction result in variations in performance and also affect the life. Therefore, a technique of providing a buffer member for reducing the stress on the cell between adjacent cells or between the cell and the housing or support member is known.

[0003] When the buffer member is a flat member, when the buffer member is compressed, the reaction force rapidly increases even at a low compression rate, and a sufficient buffer effect cannot be obtained. Further, in the case of a buffer member in which a plurality of protrusions are provided on a flat member, stress concentrates on the portion where the protrusions contact, and there is concern about a decrease in battery performance. Thus, there is still room for improvement.

[0004] For example, in the case of a lithium-ion battery, if a specific cell generates a high amount of heat for some reason, there is concern that the increase in the amount of heat generated by other cells will also be caused, resulting in thermal runaway. Therefore, a technique of providing a heat insulation function to the buffer member is also known.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] This invention provides a battery buffer structure that can improve the buffering function. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following means.

[0008] In other words, the battery buffer structure of the present invention is Cushioning sheet and A heat insulating member is placed between the cushioning sheet and the battery component, A battery buffer structure comprising, The cushioning sheet is characterized by having a protruding portion that extends toward the heat insulating member.

[0009] According to the present invention, since an insulating material is provided between the cushioning sheet and the battery components (cells, housing, support members, etc.), the stress caused by the protrusions on the cushioning sheet is distributed by the insulating material. This suppresses stress concentration on the battery components caused by the protrusions. Furthermore, in the present invention, since an insulating material is provided between the cushioning sheet and the battery components, heat propagation can be suppressed.

[0010] Furthermore, other battery buffer structures of inventions are, Cushioning sheet and Intermediate member and A battery buffer structure comprising, The cushioning sheet has a protruding portion that extends toward the interposing member, The intervening member is characterized by having a stress-distributing function that distributes the stress caused by the protruding portion.

[0011] According to the present invention, stress concentration on the battery components due to protrusions can be suppressed by an intervening member having a stress-distributing function that distributes the stress caused by the protrusions.

[0012] Furthermore, the battery buffer structure of other inventions is, Cushioning sheet and Intermediate member and A buffer structure for a battery, comprising: The buffer sheet includes a protruding portion that protrudes toward the side opposite to the mounting member, and when the battery buffer structure is compressed until the maximum thickness of the buffer sheet in the protruding direction of the protruding portion in a state where no external force is acting on the battery buffer structure is halved, a space is maintained between the tip end portion of the protruding portion and the mounting member without the back side of the tip end portion of the protruding portion contacting the mounting member.

[0013] According to the present invention, even when the battery buffer structure is compressed until the maximum thickness of the buffer sheet in the protruding direction of the protruding portion is halved, a space is maintained between the protruding portion and the mounting member, so that it is possible to suppress a sharp increase in the repulsive force caused by the battery buffer structure. Further, there is also an effect that the heat insulation function is maintained by the air in the space.

[0014] A plurality of the protruding portions may be provided on each of both surfaces of the buffer sheet.

[0015] The protruding portions provided on one surface of the buffer sheet and the protruding portions provided on the other surface of the buffer sheet may be alternately arranged vertically and horizontally.

[0016] The height of the protruding portions provided on one surface of the buffer sheet and the height of the protruding portions provided on the other surface of the buffer sheet may be the same.

[0017] Thereby, since the functions on both sides in the battery buffer structure become equivalent, there is no need to check the front and back during the attachment work of the battery buffer structure. [[ID=二十六]]

[0018] The maximum thickness of the buffer sheet in the protruding direction of the protruding portion is preferably greater than three times the thickness of the buffer sheet.

[0019] The protruding portion preferably has an area surrounded by the outer shape of a cross section perpendicular to its protruding direction that gradually narrows toward the tip in the protruding direction.

[0020] This allows for a large volume within the hollow portion to suppress a sharp increase in the elastic repulsive force, and while making it easy to maintain a space even when the buffer sheet is compressed, the area of the tip of the protruding portion can be made small. Therefore, the contact area between the protruding portion and the member with which the protruding portion comes into contact becomes small, and heat transfer can be suppressed.

[0021] It is also preferable that the buffer sheet and the heat insulating member (interposed member) are integrated.

[0022] Note that the above-described configurations can be adopted in combination as much as possible.

Advantages of the Invention

[0023] As described above, according to the present invention, the buffer function is improved.

Brief Description of the Drawings

[0024] [Figure 1] FIG. 1 is a schematic configuration diagram of a battery using a buffer structure for a battery according to Embodiment 1 of the present invention. [Figure 2] FIG. 2 is an external view of a buffer structure for a battery according to Embodiment 1 of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view of a buffer structure for a battery according to Embodiment 1 of the present invention. [Figure 4] FIG. 4 is an operation explanatory diagram of a buffer structure for a battery according to Embodiment 1 of the present invention. [Figure 5] FIG. 5 is an explanatory diagram of a buffer structure for a battery according to Embodiment 2 of the present invention. [Figure 6] FIG. 6 is a diagram showing various examples of the protruding portion according to the present invention.

Modes for Carrying Out the Invention

[0025] 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.

[0026] (Example 1) The battery buffer structure according to Embodiment 1 of the present invention will be described with reference to Figures 1 to 4. Figure 1 is a schematic diagram of a battery using the battery buffer structure according to Embodiment 1 of the present invention. Figure 2 is an external view of the battery buffer structure according to Embodiment 1 of the present invention, where (a) is a plan view of the battery buffer structure and (b) is a side view of the battery buffer structure. Figure 3 is a schematic cross-sectional view of the battery buffer structure according to Embodiment 1 of the present invention, where Figure 3(a) is the AA cross-sectional view in Figure 2(a) and Figure 3(b) is a schematic cross-sectional view of the buffer sheet alone. Figure 4 is an explanatory diagram of the operation of the battery buffer structure according to Embodiment 1 of the present invention, where (a) is a schematic cross-sectional view showing the state in which a compressive force is acting on the battery buffer structure and (b) is a graph showing the relationship between the compressibility and surface pressure.

[0027] <Battery> Referring particularly to Figure 1, an example of a battery to which the battery buffer structure according to this embodiment can be applied will be described. Here, a lithium-ion battery will be used as an example. Battery 1 is composed of a cell stack in which a plurality of cells 20 are stacked, and the cell stack is supported by a housing (case wall) that houses the cell stack and support members for supporting the cell stack. Figure 1(a) shows a part of the housing (or support member) 30.

[0028] In battery 1, a battery buffer structure 10 is provided between adjacent cells 20 and between the cells 20 and the housing (or support member) 30 in order to suppress the stress acting on the cells 20 due to the expansion and contraction of the cells 20 during charging and discharging. A battery buffer structure 10 may be provided for each individual cell 20, or a battery buffer structure 10 may be provided for each of multiple cells 20. Furthermore, multiple battery buffer structures 10 can be stacked and used between adjacent cells 20 and between the cells 20 and the housing (or support member) 30.

[0029] Furthermore, in the battery 1X shown in Figure 1(b), the cell stack 20X is housed inside the housing 30X. The housing 30X is supported by a pair of support members 30Y. In this illustrated example, a battery buffer structure 10 is provided between the housing 30X and the support members 30Y. Although not specifically shown, a battery buffer structure can also be provided between adjacent cells in the cell stack 20X.

[0030] With the battery 1 configured as described above, even if a compressive force acts on the cell 20 when it expands, the battery buffer structure 10 can suppress the stress on the cell 20. In addition, in the case of lithium-ion batteries, countermeasures against thermal runaway are necessary, so the battery buffer structure 10 is configured to have a heat insulating function.

[0031] <Battery buffer structure> The battery buffer structure 10 will now be described in detail. The battery buffer structure 10 comprises a buffer sheet 100 and interposing members 210 and 220 that are placed between the buffer sheet 100 and the battery components (such as the cell 20 and the housing (or support member) 30). As shown in the example in Figure 1(b) above, the interposing members 210 and 220 are not limited to being in direct contact with the battery components, as long as they are provided between the buffer sheet 100 and the battery components.

[0032] The cushioning sheet 100 is made of an elastic material. Preferably, this elastic material is made of a material with a hardness of 50 to 90 degrees (more preferably 60 to 80 degrees) as measured by a JIS K 6253 durometer type E. This allows the cushioning function to be effectively performed. More specifically, EPDM or silicone rubber can be used.

[0033] If the cushioning sheet 100 and the interposing members 210,220 can be positioned by incorporating them into the housing (or support member) 30, then a structure for fixing the cushioning sheet 100 and the interposing members 210,220 is unnecessary. However, if positioning is not possible, a structure for fixing the cushioning sheet 100 and the interposing members 210,220 must be provided. For example, a structure in which the cushioning sheet 100 and the interposing members 210,220 are bonded together with double-sided tape can be used, or the cushioning sheet 100 and the interposing members 210,220 can be positioned by housing them in a bag-shaped film, or any other known technology can be adopted as appropriate. Alternatively, a structure in which the cushioning sheet 100 and the battery components are bonded together with double-sided tape can be used to position them. Of course, a structure for positioning the cushioning sheet 100 and the interposing members 210,220 can also be provided on the battery components.

[0034] To provide the battery buffer structure 10 with thermal insulation, it is desirable that both the buffer sheet 100 and the intervening members 210 and 220 be made of materials with thermal insulation properties. However, depending on the usage conditions, if the necessary thermal insulation effect can be obtained by providing thermal insulation to either the buffer sheet 100 or the intervening members 210 and 220, the other member may be made of a material without thermal insulation properties. When the buffer sheet 100 is to have thermal insulation properties, a highly thermally insulating elastic material such as flame-retardant rubber or flame-retardant elastomer can be suitably applied as the material for the buffer sheet 100. When the intervening members 210 and 220 are to have thermal insulation properties, they can be made of a thin, non-combustible board mainly composed of non-asbestos natural mineral magnesium silicate. When the intervening members 210 and 220 are to have thermal insulation properties, they can be called thermal insulation members. Furthermore, it is desirable that the intervening members 210 and 220 be made of sheet-like (thin plate-like) material so as not to make the overall thickness of the battery buffer structure 10 too thick. In this embodiment, the intervening members 210 and 220 are made of sheet-like material as shown in the figure.

[0035] The cushioning sheet 100 has multiple protrusions 120a and 120b. These protrusions 120a and 120b are configured to be hollow inside, and the space within the hollow is configured to be open on the side opposite to the direction of protrusion. In other words, the cushioning sheet 100 can also be described as having multiple hollow protrusions 120a and 120b that are open on the side opposite to the direction of protrusion.

[0036] As shown in Figure 2, multiple protrusions 120a and 120b are provided on both sides of the cushioning sheet 100. In Figure 2(a), the outlines of the protrusions 120a and 120b are shown as dotted lines in a transparent view to make their arrangement easier to understand. As shown in the figure, the protrusions 120a provided on one side of the cushioning sheet 100 and the protrusions 120b provided on the other side of the cushioning sheet 100 are arranged alternately vertically and horizontally. The heights of the protrusions 120a and 120b are configured to be the same. This ensures that both sides of the battery cushioning structure 10 have the same function, eliminating the need to check the front and back when installing the battery cushioning structure 10. It should be noted that the plan view shown in Figure 2(a) is merely one example of the arrangement of the protrusions 120a and 120b, and the number and arrangement of the protrusions 120a and 120b can be appropriately set according to the dimensions of the cushioning sheet 100, etc. Furthermore, in the illustrated example, the protrusions 120a and 120b are arranged alternately parallel or perpendicular to the four sides of the cushioning sheet 100, but the protrusions 120a and 120b may also be configured to be arranged alternately diagonally to the four sides.

[0037] Here, the protrusion 120a can be described as a hollow protrusion that protrudes toward the interfacing member 210 and is open on the side opposite to the direction of protrusion. Alternatively, this protrusion 120a can also be described as a hollow protrusion that protrudes toward the side opposite to the interfacing member 220 and is open on the side facing the interfacing member 220.

[0038] On the other hand, the protruding portion 120b can be described as a hollow internal protruding portion that protrudes toward the interfacing member 220 and is open on the side opposite to the direction of protrusion. Alternatively, this protruding portion 120b can also be described as a hollow internal protruding portion that protrudes toward the side opposite to the interfacing member 210 and is open on the side facing the interfacing member 210.

[0039] Referring to Figure 3, the dimensional relationships of each part of the battery buffer structure 10 will be explained. In Figure 3(a), H1 is the maximum thickness of the buffer sheet 100 in the direction of protrusion of the protruding part when no external force is acting on the battery buffer structure 10. In Figure 3(b), the dimensions of each part of the buffer sheet 100 when no external force is acting on it are shown. H is the maximum thickness of the buffer sheet 100 in the direction of protrusion of the protruding part, T1 is the thickness of the flat plate portion of the buffer sheet 100, T2 is the thickness of the body portion of the protruding parts 120a and 120b, T3 is the thickness of the leading edge portion of the protruding parts 120a and 120b, L is the distance between the leading edge portions of adjacent protruding parts 120a and 120b, and d is the inclination angle of the body portion of the protruding parts 120a and 120b with respect to the flat plate portion. These dimensions can be adjusted as appropriate depending on the usage environment, etc. T1, T2, and T3 can all be the same, or they can be set to be different.

[0040] For example, T1 can be set to approximately 0.1 mm to 10 mm. Furthermore, to ensure sufficient cushioning function, it is preferable that H > 3 × T(T1, T2, T3) is satisfied. The length and width dimensions of the cushioning sheet 100 (as viewed in a plan view) should be equal to or slightly smaller than the length and width dimensions of the cell 20. Also, T2 can be set to approximately 0.1 mm to 10 mm. The density of the protrusions 120a and 120b should be 1 to 6 pieces / cm². 2 It can be reduced to that extent.

[0041] In this embodiment, when the battery buffer structure 10 is compressed until the maximum thickness H1 of the buffer sheet 100 in the direction of the protrusion of the protruding portion is halved, when no external force is acting on the battery buffer structure 10, the back side of the leading edge of the protrusion 120a does not come into contact with the intervening member 220, and a space is maintained between the protrusion 120a and the intervening member 220. That is, as shown in Figure 4(a), even when the battery buffer structure 10 is compressed by applying an external force in the direction of arrow P so that the compression ratio of the protrusion 120a becomes 50% (H2 = 0.5 × H1), the back side of the leading edge of the protrusion 120a does not come into contact with the intervening member 220. As a result, a space (for example, the area shown as A1 in the figure) is maintained between the protrusion 120a and the intervening member 220. The relationship between the protrusion 120b and the intervening member 210 is similar; even when the compression ratio of the protrusion 120b is 50%, a space (for example, the region shown as A2 in the figure) is maintained between the protrusion 120b and the intervening member 210.

[0042] This section describes a specific example of how a space is maintained on the back side of a protruding part even when the compression ratio of the protruding part is 50%. EPDM with a hardness of DuroA75, elongation of 250%, and tensile strength of 6.8 MPa was used as the material for the cushioning sheet 100. The hardness material properties were measured based on JIS standard JIS K6253, using a durometer type A. The elongation and tensile strength material properties were measured based on JIS standard JIS K6251, using an elongation speed of 500 mm / min. The dimensions of each part were set to H=3.3 mm, T1=0.8 mm, T2=0.6 mm, T3=1 mm, L=3.5 mm, and d=40°. The intervening member 210 was a thin, non-combustible board with a thickness of 1.2 mm and a thermal conductivity of 0.2 W / mK, primarily composed of natural mineral magnesium silicate. Figure 4(b) is a graph showing the relationship between the compressibility of the protrusions 120a and 120b and the surface pressure between the protrusions 120a and 120b and the interfacing members 210 and 220 in this specific example. The measurement conditions for this graph were a temperature of 25°C and a compression rate of 0.1 mm / min. As can be seen from this graph, it can be seen that even when the compressibility exceeds 50%, a rapid increase in surface pressure does not occur. Furthermore, when the surface pressure increases rapidly, it can be considered that the back side of the leading edge of the protrusion is in contact with the interfacing member, and the space has disappeared (or is almost completely disappeared). From this, it can be seen that if a flat plate-shaped material is used as the cushioning sheet, the surface pressure will increase rapidly even at a low compressibility. In addition, in a configuration in which multiple protrusions without hollow sections are provided on a flat plate-shaped cushioning sheet, the surface pressure does not increase in the parts without protrusions, thus suppressing the increase in the reaction force of the entire cushioning sheet, but it can also be seen that the surface pressure increases rapidly in the parts where the protrusions make contact.

[0043] <Advantages of the battery buffer structure according to this embodiment> In the battery buffer structure 10 according to this embodiment, intervening members 210 and 220 are provided between the buffer sheet 100 and the battery components (cells 20, housing 30, etc.). Therefore, the stress caused by the protrusions 120a and 120b on the buffer sheet 100 is distributed by the intervening members 210 and 220. Thus, the intervening members 210 and 220 according to this embodiment have a stress distribution function that distributes the stress caused by the protrusions 120a and 120b. Note that the intervening members 210 and 220 have a stress distribution function as long as they have a certain degree of rigidity. This makes it possible to suppress stress concentration on the battery components due to the protrusions 120a and 120b. In addition, since the protrusions 120a and 120b are hollow inside and open on the opposite side from the protrusion direction, it is possible to suppress a sudden increase in reaction force even when compressed. This makes it possible to enhance the buffer function. Therefore, the stress load on the cell 20 and other components due to the expansion and contraction of the cell 20 can be suppressed, and vibrations transmitted to the battery 1 can be absorbed. As a result, the quality of the cell 20 can be stably maintained, and the lifespan of the battery 1 can be extended.

[0044] Furthermore, if the intervening members 210 and 220 are provided with thermal insulation properties, heat propagation can be suppressed even if the temperature of any of the cells 20 rises sharply for any reason.

[0045] Furthermore, in this embodiment, even when the battery cushioning structure 10 is compressed until the maximum thickness of the cushioning sheet 100 in the direction of protrusion is halved, a space is maintained between the protrusion and the intervening member. Therefore, it is possible to suppress a sudden increase in the repulsive force of the battery cushioning structure 10. In addition, the air in the space helps maintain the heat insulation function.

[0046] Furthermore, the projections 120a and 120b in this embodiment are configured such that the area surrounded by the cross-sectional shape perpendicular to the projection direction gradually narrows towards the tip in the projection direction. That is, the outer shape of the projections 120a and 120b in this embodiment is a substantially frustoconical shape with the tip of the cone being a curved surface. Therefore, when the projections 120a and 120b are cut by a plane perpendicular to the projection direction, the outer shape is circular, and the area of ​​the circle is configured to gradually narrow towards the tip in the projection direction.

[0047] This configuration allows for a larger volume within the hollow portion of the protrusions 120a and 120b, suppressing a rapid increase in elastic rebound force and making it easier to maintain space even when the cushioning sheet 100 is compressed, while also reducing the surface area of ​​the tips of the protrusions 120a and 120b. Consequently, the contact area between the protrusions 120a and 120b and the cell 20, housing 30, etc., is reduced, thereby suppressing heat transfer.

[0048] Here, the external shape of the protruding portion is not limited to the approximately frustoconical shape described in Example 1, but can be any shape. Example 2 describes the case where the external shape of the protruding portion is hemispherical.

[0049] (Example 2) Figure 5 shows Embodiment 2 of the present invention. In this embodiment, the configuration when the outer shape of the protruding part is hemispherical will be described. The other configurations and operations are the same as in Embodiment 1, so the same reference numerals are used for the same components, and their descriptions are omitted as appropriate.

[0050] Figure 5 is an explanatory diagram of a battery buffer structure according to Embodiment 2 of the present invention, where (a) is a plan view of the battery buffer structure, (b) is a side view of the buffer sheet, and (c) is a graph showing the relationship between compressibility and surface pressure.

[0051] The batteries to which the battery buffer structure 10X according to this embodiment can be applied are the same as in Embodiment 1, so their description will be omitted. The battery buffer structure 10X is composed of a buffer sheet 100X and interposing members 210 and 220, similar to Embodiment 1. The interposing members 210 and 220 are as described in Embodiment 1. Note that in Figure 5, only the interposing member 210 is shown in (a). The necessity of a structure for fixing the buffer sheet 100X and the interposing members 210 and 220, and the structure when fixing them, are also as described in Embodiment 1. The configuration when the battery buffer structure 10X has a heat insulating function is also as described in Embodiment 1.

[0052] The cushioning sheet 100X according to this embodiment has a plurality of protrusions 121a, 121b. These protrusions 121a, 121b are also configured to be hollow inside, similar to Embodiment 1, and the space within the hollow is configured to be open on the side opposite to the direction of protrusion of the protrusion. In other words, the cushioning sheet 100 XIt can also be said that it has multiple hollow protrusions 121a, 121b, with the opposite side of the protrusion direction open. In this embodiment, the only difference from Embodiment 1 is that the outer shape of the protrusions 121a, 121b is hemispherical. In Figure 5(b), the outlines of the hollow parts of the leftmost protrusion 121a and the second protrusion 121b from the left are shown by dotted lines. As shown in Figure 5(b), multiple protrusions 121a, 121b are provided on both sides of the cushioning sheet 100X. In Figure 5(a), the outlines of the protrusions 121a, 121b are shown as dotted lines in a transparent view to make the arrangement of the protrusions 121a, 121b easier to understand. As shown in the figure, the protrusions 121a provided on one side of the cushioning sheet 100X and the protrusions 121b provided on the other side of the cushioning sheet 100X are arranged alternately vertically and horizontally. The height of the protrusion 121a and the height of the protrusion 121b are configured to be the same, as in Example 1. Note that the plan view shown in Figure 5(a) is merely an example of the arrangement of the protrusions 121a and 121b, and it goes without saying that the number and arrangement of the protrusions 121a and 121b can be appropriately set according to the dimensions of the cushioning sheet 100X. Also, in the illustrated example, the cushioning sheet 100 X The protrusions 121a and 121b are arranged alternately parallel or perpendicular to the four sides of the surface, but the protrusions 121a and 121b may also be configured to be arranged alternately diagonally to the four sides.

[0053] Here, the protrusion 121a can be described as a hollow protrusion that projects toward the interfacing member 210 and is open on the side opposite to the direction of projection. Alternatively, this protrusion 121a can also be described as a hollow protrusion that projects toward the side opposite to the interfacing member 220 and is open on the side facing the interfacing member 220.

[0054] On the other hand, the protruding portion 121b can be described as a hollow internal protruding portion that protrudes toward the interfacing member 220 and is open on the side opposite to the direction of protrusion. Alternatively, this protruding portion 121b can also be described as a hollow internal protruding portion that protrudes toward the side opposite to the interfacing member 210 and is open on the side facing the interfacing member 210.

[0055] Referring to Figure 5, the dimensional relationships of each part of the battery buffer structure 10 will be explained. In Figure 5(b), the dimensions of each part of the buffer sheet 100X are shown when no external force is acting on it. H is the maximum thickness of the buffer sheet 100X in the direction of the protrusion, T1 is the thickness of the flat portion of the buffer sheet 100X, and L is the distance between the leading edges of adjacent protrusions 121a and 121b. These dimensions can be adjusted as appropriate depending on the operating environment. For example, T1 can be set to approximately 0.1 mm to 10 mm. Furthermore, in order to fully perform the buffering function, it is preferable that H > 3 × T1 be satisfied. The length and width dimensions of the buffer sheet 100X (length and width when viewed in a plan view) should be the same as or slightly smaller than the length and width dimensions of the cell 20. The density of protrusions 121a and 121b should be 1 to 6 pieces / cm 2 It can be reduced to that extent.

[0056] In this embodiment as well, when the battery buffer structure 10X is compressed until the maximum thickness of the buffer sheet 100X in the direction of the protrusion is halved, while no external force is acting on the battery buffer structure 10X, the back side of the leading edge of the protrusion 121a does not come into contact with the intervening member 220, and a space is maintained between the protrusion 121a and the intervening member 220.

[0057] This section describes a specific example of how a space is maintained on the back side of a protrusion even when the compression ratio of the protrusion is 50%. EPDM with a hardness of DuroA75, elongation of 250%, and tensile strength of 6.8 MPa was used as the material for the cushioning sheet 100X. The measurement conditions for each material property were the same as in Example 1. The dimensions of each part were set to H=3.5mm, T1=0.5mm, and L=3.5mm. The interposing member 210 was a thin, non-combustible board mainly composed of magnesium silicate, a non-asbestos natural mineral, with a thickness of 1.2mm and a thermal conductivity of 0.2 W / mK. Figure 5(c) is a graph showing the relationship between the compression ratio of the protrusions 121a and 121b and the surface pressure between the protrusions 121a and 121b and the interposing members 210 and 220 in this specific example. This graph was obtained by 3D nonlinear structural analysis. The analysis conditions were set as follows: the analysis element was a hexahedral first-order element, the temperature was room temperature, the material of the cushioning sheet was EPDM, and the material of the insulation member was non-combustible board. As can be seen from this graph, similar to Example 1, a rapid increase in surface pressure does not occur even when the compression ratio exceeds 50%.

[0058] The battery buffer structure 10X according to this embodiment, configured as described above, can also obtain the same effects as in the above embodiment 1.

[0059] (others) Regarding the external shape of the protrusion, configurations other than the approximately frustoconical shape described in Example 1 and the hemispherical shape described in Example 2 can be adopted. That is, the protrusion only needs to be configured such that the area surrounded by the external cross-section perpendicular to its protrusion direction gradually narrows towards the tip in the protrusion direction. For example, as shown in Figures 6(a) and (b), a protrusion 122 in which the tip of a square pyramid is composed of a curved surface can be adopted. Figure 6(a) is a plan view of the protrusion 122, and Figure 6(b) is a side view. Of course, not only square pyramids but also shapes with curved surfaces at the tips of polygonal pyramids such as triangular pyramids and pentagonal pyramids can be adopted. Furthermore, as shown in Figures 6(c), (d), and (e), a protrusion 123 in the shape of a cylinder cut in half can also be adopted. Figure 6(c) is a plan view of the protrusion 123, Figure 6(d) is a view of the protrusion 123 in the direction of P1 in Figure 6(c), and Figure 6(e) is a view of the protrusion 123 in the direction of P2. It goes without saying that the inside of the protrusions 122 and 123 is hollow.

[0060] In the above embodiment, a configuration in which protrusions are provided on both sides of the cushioning sheet was shown. However, the present invention also includes a configuration in which protrusions are provided on only one side. In this case, a configuration in which the intervening member is placed only on the side on which the protrusions are provided can be adopted. As a result, the intervening member exhibits a stress distribution function that distributes the stress caused by the protrusions. Furthermore, a configuration in which the intervening member is placed only on the side opposite to the side on which the protrusions are provided can also be adopted. As a result, the escape of air from within the hollow portion can be suppressed, and even when the compressibility of the protrusions is 50%, it is easier to maintain space on the back side of the protrusions. Of course, as in each embodiment, it is desirable to provide intervening members on both sides.

[0061] Furthermore, the above embodiment shows a configuration in which protrusions of the same dimensions and shape are provided on both sides of the cushioning sheet. However, when protrusions are provided on both sides of the cushioning sheet, it is not always necessary for the protrusions on both sides to have the same dimensions and shape. In other words, it is possible to provide protrusions of the same shape on both sides, and for the height of the protrusions on one side to be different from the height of the protrusions on the other side. Also, for example, the protrusions shown in Embodiment 1 can be used on one side, and the protrusions shown in Embodiment 2 can be used on the other side, in which case the heights of the protrusions may be the same or different.

[0062] Furthermore, although the above embodiment shows a case where the cushioning sheet and the intervening member (insulating member) are made of separate members, it is also possible to construct a battery cushioning structure using a member that has the portion corresponding to the cushioning sheet and the portion corresponding to the intervening member as a single unit. In other words, it is also possible to configure the cushioning sheet and the intervening member (insulating member) to be integrated. [Explanation of symbols]

[0063] 1:Battery 10,10X:Battery buffer structure 20: Cell 30: Housing (support member) 100,100X: Cushioning sheet 120a, 120b, 121a, 121b, 122, 123: Protrusion 210,220: Intermediate components

Claims

1. Cushioning sheet and A heat insulating member is placed between the cushioning sheet and the battery component, A battery buffer structure comprising, The cushioning sheet has a protrusion that extends toward the heat insulating member, A battery buffer structure characterized in that the buffer sheet and the heat insulating member are integrated into one unit.

2. A flat cushioning sheet, Intermediate member and A battery buffer structure comprising, The cushioning sheet has a projection on one surface of the flat plate that protrudes toward the opposite side from the interposing member, with the opposite side of the projection being open, and a projection on the other surface of the flat plate that protrudes toward the interposing member, with the opposite side of the projection being open, A battery cushioning structure characterized in that, when the battery cushioning structure is compressed until the maximum thickness of the cushioning sheet in the direction of protrusion of the protruding portion is halved while no external force is acting on the battery cushioning structure, the back side of the leading edge of the protruding portion on one surface does not come into contact with the intervening member, and a space is maintained between the protruding portion on one surface and the intervening member.

3. The battery cushioning structure according to claim 1, characterized in that a plurality of the protrusions are provided on both sides of the cushioning sheet.

4. The battery buffer structure according to claim 2 or 3, characterized in that the protrusions provided on one side of the buffer sheet and the protrusions provided on the other side of the buffer sheet are arranged alternately in a vertical and horizontal direction.

5. The battery cushioning structure according to claim 2 or 3, characterized in that the height of the protrusion provided on one side of the cushioning sheet is the same as the height of the protrusion provided on the other side of the cushioning sheet.

6. The maximum thickness of the cushioning sheet in the direction of the protrusion of the protruding portion is the thickness of the cushioning sheet. The battery buffer structure according to claim 2 or 3, characterized in that it is more than three times thicker.

7. The battery buffer structure according to claim 1, 2, or 3, characterized in that the area surrounded by the outer shape of the cross-section perpendicular to the direction of protrusion gradually narrows towards the tip in the direction of protrusion.

8. The battery cushioning structure according to claim 2, characterized in that the cushioning sheet and the intervening member are integrated.

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