JP2023152549A - Buffer material for battery - Google Patents

Abstract

To realize a buffer material for a battery, which is adopted to sufficiently absorb a displacement amount while maintaining a sufficient reaction force.SOLUTION: A buffer material 1 for a battery comprises: a plurality of contact parts 2 each of which has an opposite surface 2a facing a rigid body, has a U-shape concave in a state of a pre-compression, and contacts a rigid body along a surface of the rigid body when compressed; and a plurality of column parts 3 that connects a contact part 2 contacted to one rigid body and a contact part 2 contacted to the other rigid body, and is deformed in an S-curved shape when compressed. The buffer material 1 for the battery has a continuous M-shaped construction formed by alternately continuing the plurality of contact parts 2 and the plurality of column parts 3. Two adjacent column parts 3 form a hollow space S between the two column parts 3 in a state of a pre-compression. Deformation of each column part 3 in an aspect where a part compressed and curved in an S-shape is housed in the space S reduces the hollow space S and the buffer material 1 for the battery is reduced in a thickness direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to a cushioning material for batteries. More specifically, the present invention relates to a battery cushioning material used in batteries such as secondary batteries used in electric vehicles and the like.

BACKGROUND ART In batteries, a battery cushioning material that is interposed between two plate-like rigid bodies facing each other and elastically relieves the compressive force between the two rigid bodies has been known. For example, in batteries (secondary batteries) used in electric vehicles, etc., there is a case between multiple battery cells that make up the battery, or between a stack of multiple battery cells and a casing (restricted) that holds it in a sandwiched manner. A typical example is a battery cushioning material disposed between the battery and the battery (for example, see Patent Document 1). By interposing such a battery cushioning material between the rigid bodies, it is possible to secure the compressive force necessary to maintain the integrity of the entire structure including these rigid bodies while alleviating excessive compressive force.

Japanese Patent Application Publication No. 2020-4556

In general, a battery cushioning material can absorb a sufficient amount of displacement while maintaining a high reaction force (surface pressure) against the compressive force between the rigid bodies that is initially applied after being placed between the rigid bodies. However, once the compressive force load is released, it becomes difficult to exert sufficient reaction force due to so-called hysteresis loss. It may be possible to make the battery cushioning material dense in advance so that sufficient reaction force can be exerted after the load is released, but in this case, the amount of displacement that can be absorbed becomes small. Therefore, further efforts are required to sufficiently absorb the amount of displacement while maintaining sufficient reaction force.

In view of the above circumstances, the present invention aims to realize a battery cushioning material suitable for sufficiently absorbing displacement while maintaining sufficient reaction force.

In order to solve the above problems, the present invention provides the following battery cushioning material.

[1] In a battery cushioning material that is interposed between two plate-like rigid bodies facing each other and elastically relieves the compressive force between the two rigid bodies, one of the two rigid bodies is The opposing surface facing the rigid body has a U-shaped concave shape in a cross section along the thickness direction of the battery cushioning material before receiving the compressive force, and has a U-shaped concave shape in a cross section along the thickness direction of the battery cushioning material. a plurality of contact parts each having an opposing surface that contacts one of the rigid bodies along the surface of one of the rigid bodies; and one of the two rigid bodies among the plurality of contact parts. A contact portion that contacts a rigid body and a contact portion that contacts the other of the two rigid bodies among the plurality of contact portions are connected, and S is formed in the cross section by receiving the compressive force. It is equipped with a plurality of pillar parts that are deformed into a shape curved in a character shape,
The battery cushioning material has an M-shaped continuous structure in which the plurality of contact parts and the plurality of pillar parts are alternately connected in the cross section, and among the plurality of pillar parts, The two mutually adjacent struts form a hollow space between the two struts before receiving the compressive force, and are curved in an S-shape by receiving the compressive force. The two pillars are deformed in such a manner that the bent portions of the two pillars are accommodated in the hollow space, thereby collapsing the hollow space and reducing the thickness of the battery cushioning material. Cushioning material for batteries.

[2] The battery cushioning material according to [1], wherein the two support columns form a substantially V-shaped hollow space in the cross section as the hollow space.

[3] The plurality of support columns have a flat surface represented by a straight line in the cross section before receiving the compressive force from the two rigid bodies [1] or [2] ] Battery cushioning material described in .

[4] The plurality of support columns have a non-flat surface represented by repeated unevenness in the cross section before receiving the compressive force from the two rigid bodies [1] or The battery cushioning material according to [2].

In the present invention, the support column bends in an S-shape in response to compressive force from two rigid bodies, and the bent portion is accommodated in the hollow space between the two adjacent support columns, resulting in a displacement amount. can be absorbed sufficiently. Moreover, even after the load of the compressive force is released, the compressive stress tends to remain in the bent portion, and a sufficient reaction force can be maintained. As a result, the present invention provides a battery cushioning material suitable for sufficiently absorbing displacement while maintaining sufficient reaction force.

FIG. 1 is a cross-sectional view schematically showing how a battery cushioning material according to an embodiment of the present invention is used. FIG. 2 is a cross-sectional view schematically showing another usage state of the battery cushioning material of FIG. 1; FIG. 3 is a perspective view of the battery cushioning material of FIGS. 1 and 2. FIG. FIG. 4 is a sectional view of the battery cushioning material of FIG. 3 in a state before receiving compressive force from two rigid bodies. FIG. 5 is a cross-sectional view when the battery cushioning material of FIG. 4 receives compressive force from two rigid bodies. FIG. 6 is a cross-sectional view of the battery cushioning material of FIG. 4 when it receives a compressive force larger than that of FIG. 5 from two rigid bodies. FIG. 7 is a diagram showing the distribution of compressive stress remaining after the compressive force load is released in the battery cushioning materials of FIGS. 3 to 6. FIG. FIG. 7 is a graph showing a change in reaction force with respect to the amount of compression for one specific example of the battery cushioning material shown in FIGS. 3 to 6. FIG. FIG. 7 is a cross-sectional view along the thickness direction of a part of a battery cushioning material according to another embodiment of the present invention, in which a plurality of support portions have non-flat surfaces.

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and it is understood that changes and improvements in the design may be made as appropriate based on the common knowledge of those skilled in the art without departing from the spirit of the present invention. It should be.

The battery cushioning material of this embodiment is a battery cushioning material that is interposed between two plate-shaped rigid bodies facing each other and elastically relieves the compressive force between the rigid bodies, and is made of an elastic material (typical are made of rubber or elastomer).

FIG. 1 is a sectional view schematically showing a usage state of the battery cushioning material 1 according to an embodiment of the present invention, and FIG. 2 is a sectional view schematically showing another usage state of the battery cushioning material 1 of FIG. 1. It is a diagram.

The battery cushioning material 1 of this embodiment can be arranged between adjacent battery cells 210 like the battery 200 shown in FIG. It can be placed between the body 220 and the restraint part 230. Note that the number of battery cushioning materials 1 is not limited to one, and a plurality of them can also be used. In this case, a plurality of battery cushioning materials 1 may be stacked and used, a plurality of them may be arranged on a plane, or a combination of these may be used. The battery is not limited to an all-solid-state battery, but may also be a liquid electrolyte battery.

3 is a perspective view of the battery cushioning material 1 of FIGS. 1 and 2, and FIG. 4 is a cross-sectional view of the battery cushioning material 1 of FIG. 3 in a state before receiving compressive force from two rigid bodies. 5 is a sectional view when the battery cushioning material 1 of FIG. 4 receives compressive force from the two rigid bodies 10 and 20, and FIG. FIG. 6 is a cross-sectional view when a compressive force larger than that in the state shown in FIG. 5 is applied from the state shown in FIG.

The battery cushioning material 1 extends continuously in the horizontal direction (horizontal direction) in each of FIGS. 3 to 6, and only a portion thereof is shown in FIGS. 3 to 6. Here, in the present application, "the state before receiving compressive force from the two rigid bodies" means that the battery cushioning material 1 has never been interposed between the two rigid bodies 10 and 20 and is in the state of being a single body at the time of manufacture. This refers to a state where the shape of the battery cushioning material 1 is maintained as it is, that is, a state before being used as a battery cushioning material. In addition, the rigid bodies 10 and 20 may be, for example, battery cells that constitute a battery (secondary batteries) used in electric vehicles or the like, or housings that sandwich and hold a stack of such battery cells. To be precise, the wall of the housing) can be mentioned. In this case, the battery cushioning material 1 functions as a battery cushioning material disposed between the battery cells or between the battery cell stack and the casing.

As shown in FIG. 4, the battery cushioning material 1 includes a plurality of contact portions 2 and a plurality of support portions 3 as its constituent parts.

Each of the plurality of contact portions 2 has an opposing surface 2a that faces the upper rigid body 10 in FIG. 4 or the lower rigid body 20 in FIG. As shown in FIG. 4, the opposing surface 2a has a U-shaped concave shape in a cross section along the thickness direction of the battery cushioning material 1 before receiving compressive force from the rigid bodies 10 and 20. There is. Because of the U-shaped concave shape, when receiving compressive force from the rigid bodies 10 and 20, the opposing surface 2a moves along the surfaces of the rigid bodies 10 and 20, as shown in FIGS. 5 and 6. , 20 and come into contact with each other. As a result, the compressed state of the battery cushioning material 1 is stabilized.

As shown in FIG. 4, the plurality of support columns 3 are portions that connect the contact portion 2 that contacts the upper rigid body 10 in FIG. 4 and the contact portion 2 that contacts the lower rigid body 20 in FIG. be. As shown in FIGS. 5 and 6, the plurality of support columns 3 are deformed into an S-shaped curved shape upon receiving the compressive force from the rigid bodies 10 and 20. Here, the degree of curvature depends on the compression force from the rigid bodies 10 and 20, and the greater the compression force, the greater the degree of curvature. For example, in FIG. 5, the degree of S-shaped curvature is slight, but in FIG. 6, the degree of S-shaped curvature is extremely large.

As shown in FIG. 4, the plurality of contact portions 2 and the plurality of support portions 3 are arranged alternately in the left-right direction of FIG. 4, so that the battery cushioning material 1 has a continuous M-shaped structure. It will be held.

Here, in the state before receiving the compressive force from the rigid bodies 10 and 20, two of the plurality of support pillars 3 that are adjacent to each other are between the two support pillars 3 as shown in FIG. A hollow space S is formed in the space. As shown in FIGS. 5 and 6 (particularly FIG. 6), the bent portions 3a of the two S-shaped support columns 3 are bent into the hollow space S by receiving the compressive force from the rigid bodies 10 and 20. The two support columns 3 are deformed in the manner in which they are accommodated. This deformation collapses the hollow space S and reduces the thickness of the battery cushioning material 1.

In the battery cushioning material 1, the support pillars 3 are bent into an S-shape by receiving the compressive force from the two rigid bodies 10 and 20, and the bent portion is a hollow space between two adjacent support pillars 3. By being accommodated in S, the amount of displacement can be sufficiently absorbed. Moreover, even after the load of the compressive force is released, the compressive stress tends to remain in the bent portion, and a sufficient reaction force can be maintained. As a result, the battery cushioning material 1 is a battery cushioning material suitable for sufficiently absorbing displacement while maintaining sufficient reaction force.

FIG. 7 is a diagram showing the distribution of compressive stress remaining after the compressive force load is released in the battery cushioning material 1 of FIGS. 3 to 6.

As shown in FIG. 7, the compressive stress tends to remain in the S-shaped bent portion of the support portion 3, particularly in the vicinity of the bent inner surface 3b. Since the battery cushioning material 1 of FIG. 4 has a shape that realizes such an inner surface 3b, a sufficient reaction force can be maintained even after the compressive force load is released.

FIG. 8 is a diagram showing a graph of the change in reaction force with respect to the amount of compression for one specific example of the battery cushioning material 1 shown in FIGS. 3 to 6. For reference, FIG. 8 also shows a graph of the change in reaction force with respect to the amount of compression for a conventional battery cushioning material made of a flat foam.

FIG. 8 shows a graph A1 of the change in reaction force with respect to the amount of compression when a compressive force load is applied for the first time for a specific example of the battery cushioning material 1, and a graph A1 showing the change in reaction force with respect to the amount of compression when a compressive force load is applied for the first time, and a graph A1 showing a change in reaction force against the amount of compression when a compressive force load is applied for the first time, and a graph A1 for a specific example of the battery cushioning material 1. Graph A2 shows a change in reaction force with respect to the amount of compression when a load of compressive force is applied. In addition, for conventional battery cushioning materials, graph B1 shows the change in reaction force against the amount of compression when a compressive force is applied for the first time, and the second compressive force after the load is released. A graph B2 of the change in reaction force with respect to the amount of compression when applied is also shown.

With conventional battery cushioning materials, when compressive force is applied for the first time, as shown in graph B1 in Figure 8, a sufficient amount of compression (displacement) is achieved while maintaining a somewhat high reaction force (surface pressure). can be absorbed. However, in response to the second compression force load after the compression force load is released, as shown in graph B2 of Figure 8, it becomes difficult to exert sufficient reaction force unless the compression force is considerably compressed. (so-called hysteresis loss).

On the other hand, in one specific example of the battery cushioning material 1, when compressive force is applied for the first time, as shown in graph A1 of FIG. ) can absorb a sufficient amount of compression (displacement). In addition, when the compressive force is applied for the second time after the compressive force is released, as shown in graph A2 in Figure 8, the compression is not as great as compared to conventional battery cushioning materials. It is designed to be able to exert sufficient reaction force.

As described above, this specific example of the battery cushioning material 1 is more suitable for sufficiently absorbing displacement while maintaining sufficient reaction force than conventional battery cushioning materials made of flat foam. It is used as a cushioning material for batteries.

Here, in the graph A2 of FIG. 8, there is a plateau region P in which the reaction force remains approximately constant even if the amount of compression increases. As shown in FIG. 6, this corresponds to a state in which the bent portions 3a of the two S-shaped support columns 3 are about to occupy the hollow space S, and in this state, the amount of compression increases. Even if the hollow space S completely disappears, the reaction force remains high and does not change much. The existence of such a plateau region P prevents a sudden increase in reaction force against volume compression (thickness reduction) of the battery cushioning material 1. Here, the reaction force in the plateau region P adjusts the thickness and shape of the battery cushioning material 1 in the initial state before compression (for example, the angle formed between the support portion 3 and the contact portion 2), the Young's modulus of the material, etc. This allows adjustment to the desired size.

The explanation will be continued by returning to FIGS. 3 to 6.

In the present invention, as shown in FIG. 4, it is preferable that the two support columns 3 form a substantially V-shaped hollow space S. Here, the term "substantially V-shaped" refers to a shape close to a V-shape, and in addition to the V-shape itself, it also has a shape with a rounded bottom that approaches a U-shape, and the width increases as it approaches the bottom. means a shape that becomes narrower.

Since the two support columns 3 form the substantially V-shaped hollow space S in this way, the bent portions 3a of the two support columns 3 curved in an S-shape can be easily accommodated in the hollow space S. , it is possible to avoid a sudden change in the reaction force with respect to a change in the amount of compression.

Further, in the present invention, as shown in FIG. 4, before the battery cushioning material 1 receives compressive force from the two rigid bodies 10 and 20, the plurality of support columns 3 are straight in this cross-sectional view. A configuration with a flat surface as depicted is preferred.

According to such a form, since the shapes of the plurality of support columns 3 are simple, it is easy to manufacture the battery cushioning material 1.

However, in the present invention, in a state before the battery cushioning material is subjected to compressive force, a configuration may be adopted in which the plurality of support portions have non-flat surfaces represented by repeated unevenness in the cross-sectional view. . Hereinafter, an embodiment different from the battery cushioning material 1 shown in FIGS. 3 to 6, which has such a configuration, will be described.

FIG. 9 is a sectional view along the thickness direction of a part of a battery cushioning material 1' according to another embodiment of the present invention, in which a plurality of support portions 3' have non-flat surfaces.

In FIG. 9, the same components as those of the battery cushioning material 1 of FIGS. 3 to 6 are denoted by the same reference numerals, and redundant explanation thereof will be omitted. Unlike the battery cushioning material 1 of FIGS. 3 to 6, the battery cushioning material 1' in FIG. It includes a plurality of support columns 3' having non-flat surfaces, and is the same as the battery cushioning material 1 shown in FIGS. 3 to 6 except for this point.

Compared to the battery cushioning material 1 shown in FIGS. 3 to 6, such a battery cushioning material 1' has a complicated shape of the plurality of support columns 3, so that it is difficult to manufacture the battery cushioning material 1. That's a disadvantage. However, compared to the struts 3 of the battery cushioning material 1 shown in FIGS. 3 to 6, the struts 3' of the battery cushioning material 1' are more likely to bend and deform, causing internal strain in the battery cushioning material 1'. Hard to occur. Therefore, it is advantageous in terms of preventing internal strain.

The above is the description of the embodiment of the present invention.

In the above explanation, one sheet of battery cushioning material interposed between two rigid bodies has been described, but the present invention provides a structure in which a plurality of sets of two rigid bodies and one battery cushioning material are stacked one on top of the other. It may be applied to a laminate.

INDUSTRIAL APPLICABILITY The present invention is useful for realizing a battery cushioning material suitable for sufficiently absorbing displacement while maintaining sufficient reaction force.

1,1': Battery cushioning material,
2: Contact part,
2a: Opposing surface,
3, 3': Support part,
3a: bent part,
3b: inner surface,
10, 20: rigid body,
200, 201: battery,
210: battery cell,
220: laminate,
230: Restraint part,
A1, A2, B1, B2: graph,
P: plateau region,
S: Hollow space.

Claims (4)

A battery cushioning material that is interposed between two plate-shaped rigid bodies facing each other and elastically relieves the compressive force between the two rigid bodies,
an opposing surface facing one of the two rigid bodies, which is recessed in a U-shape in a cross section along the thickness direction of the battery cushioning material in a state before receiving the compressive force; a plurality of abutting portions each having an opposing surface that receives the compressive force and abuts the one of the rigid bodies along the surface of the one of the rigid bodies;
A contact portion that contacts one of the two rigid bodies among the plurality of contact portions, and a contact portion that contacts the other of the two rigid bodies among the plurality of contact portions. a plurality of support portions connected to the abutment portions that are in contact with each other and deformed into an S-shaped curved shape in the cross section in response to the compressive force;
The battery cushioning material has a configuration in which the plurality of abutting portions and the plurality of support portions are alternately connected in the cross section to form a continuous M-shape;
Two of the plurality of support pillars that are adjacent to each other form a hollow space between the two support pillars before receiving the compressive force, and By deforming the two pillars in such a manner that the bent portions of the two pillars curved in an S-shape are accommodated in the hollow space, the hollow space is collapsed and the thickness of the battery cushioning material is reduced. Cushioning material for batteries that shrinks in size. The battery cushioning material according to claim 1, wherein the two support columns form a hollow space having a substantially V-shape in the cross section as the hollow space. The battery according to claim 1 or 2, wherein the plurality of support portions have a flat surface represented by a straight line in the cross section before receiving the compressive force from the two rigid bodies. Cushioning material. 3. The plurality of support columns have a non-flat surface represented by repeated unevenness in the cross section before receiving the compressive force from the two rigid bodies. Cushioning material for batteries.

Images