Buffer sheet and method for manufacturing the same

Abstract

The buffer sheet (30) has a plurality of main support portions (31) extending in a predetermined reference direction (Y) and arranged in contact with the first member (A) at least in part of a wide surface (31a) and in contact with the second member (B) at least in part of a narrow surface (31b) opposite the wide surface (31a), and a band-shaped linking portion (32) linking adjacent main support portions (31) and arranged in contact with the first member (A) and in a state of having a distance from the second member (B). A main recess portion (31c) extending in the reference direction (Y) and opened on the first member (A) side is formed in a central portion in a width direction of the wide surface (31a) of the main support portion (31). A sub recess portion (33, 34) extending in the reference direction (Y), opened on at least one side of the first member (A) and the second member (B), and having a smaller opening width than the main recess portion (31c) is formed in a boundary portion of the main support portion (31) and the linking portion (32).

Description

TECHNICAL FIELD

[0001] The present application relates to a cushion sheet and a manufacturing method thereof. BACKGROUND

[0002] For example, in Patent Literatures 1 to 3, a cushion sheet that absorbs deformation of a battery cell is disposed between battery cells in a battery module in which a plurality of battery cells are stacked. The cushion sheet (referred to as a spacer) described in Patent Literature 3 is provided with a convex portion that contacts the battery cell, and a recessed portion (referred to as a spacing portion, a space portion) is formed on the back surface side of the convex portion. By providing the recessed portion on the back surface side of the convex portion, the convex portion is able to elastically deform in the thickness direction in the case where the battery cell has undergone swelling deformation.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURES

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2012-59380

[0006] Patent Literature 2: Japanese Patent Application Publication No. 2018-81790

[0007] Patent Literature 3: Japanese Patent Application Publication No. 2019-128991 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In the case where the interval distance between the two battery cells sandwiching the cushion sheet becomes short as the battery cell swells and deforms, the amount of compression deformation of the convex portion of the cushion sheet becomes large. With the compression deformation of the convex portion, the volume of the recessed portion on the back surface side of the convex portion becomes small. In this way, elastic deformation of the volume amount of the recessed portion can be absorbed. However, if the recessed portion becomes filled, the supporting force of the convex portion becomes large abruptly.

[0010] Therefore, in order to further increase the amount of deformation in the thickness direction of the cushion sheet, it is possible to achieve by increasing the recessed portion on the back surface side of the convex portion. However, in order to secure the rigidity of the convex portion (the supporting force of the convex portion), it is not easy to increase the recessed portion.

[0011] The present application was achieved in view of the above-described background, and an object thereof is to provide a cushion sheet and a manufacturing method thereof, which can sufficiently have a supporting force of the cushion sheet and can increase the amount of deformation in the thickness direction of the cushion sheet.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] One embodiment of the present application relates to a cushion sheet that is formed of an elastic material and is sandwiched between a first member and a second member that face each other, the cushion sheet including:

[0014] a plurality of main support portions extending in a predetermined reference direction in a face direction of the cushion sheet, formed in a narrow head shape having a wide face and a narrow face facing away in a cross section orthogonal to the reference direction, and arranged in a state in which at least a part of the wide face is in contact with the first member and in a state in which the narrow face is in contact with the second member; and

[0015] a band-shaped linking portion linking the wide face side of the inclined side of the narrow head shape to each other in adjacent main support portions, arranged in a state in contact with the first member and in a state having a distance from the second member,

[0016] a main recess portion extending in the reference direction and opened on the first member side is formed in a central portion in a width direction of the narrow head shape in the wide face of the main support portion,

[0017] a sub recess portion extending in the reference direction and opened on at least one side of the first member and the second member and having a smaller opening width than the main recess portion is formed in a boundary portion of the main support portion and the linking portion.

[0018] Another aspect of the present application relates to a manufacturing method of the above-described cushion sheet, in the manufacturing method,

[0019] an elastic material using a resin or an elastomer as a main material is extruded in a state in which an extrusion direction coincides with the reference direction, and a cross-sectional shape orthogonal to the extrusion direction is extrusion-molded in a C-letter shape or a U-letter shape,

[0020] a slit of the C-letter shape or the U-letter shape extrusion-molded in a manner in which both ends are spread from the main recess portion and the sub recess portion.

[0021] Effects of the Invention

[0022] According to the above-described cushion sheet, the main recess portion is formed on the wide face side of the main support portion. Therefore, in a case in which the interval distance between the first member and the second member is shortened, the main support portion is deformed in the height direction in a manner in which the volume of the main recess portion is reduced. In this way, the main recess portion functions as a region that absorbs the deformation of the main support portion.

[0023] In addition, the sub recess portion is formed in the boundary portion of the main support portion and the linking portion. Therefore, in a case in which the interval distance between the first member and the second member is shortened, the sub recess portion functions as a region that absorbs the deformation of the main support portion in addition to the main recess portion.

[0024] Furthermore, by forming a main recess on the wide side of the main support portion, the main support portion is designed to deform by increasing the width of its wide surface when the distance between the first and second members decreases. As a result, the connecting portion bears a compressive load from the adjacent main support portion in the bandwidth direction of the connecting portion. At this time, the connecting portion is prone to buckling in the bandwidth direction starting from the secondary recess. That is, the connecting portion becomes convex, bending from the secondary recess towards the second member side as the width of the main support portion increases. Through the bending deformation of the connecting portion, the main support portion can be further deformed in the planar direction, increasing the amount of deformation in the height direction of the main support portion.

[0025] In this way, by forming a main recess and a secondary recess, the adjacent spaces of the main recess, the secondary recess, and the inclined sides of the main support function as areas that absorb deformation of the main support. As a result, the amount of deformation in the height direction of the main support can be increased. In addition, since the structure is not limited to the main recess as an area that absorbs deformation of the main support, the rigidity of the inclined waists on both sides of the main support in the width direction can be ensured, thereby sufficiently ensuring the supporting force of the main support.

[0026] Assuming that a flat buffer sheet is extruded using an extruder, the maximum width of the extruder die needs to be greater than the width of the buffer sheet. Therefore, if the width of the buffer sheet increases, the extruder die needs to be larger. However, as described above, according to the buffer sheet manufacturing method, a cross-sectional shape orthogonal to the extrusion direction is extruded into a C-shape or U-shape using an extruder, and then unfolded with C-shaped or U-shaped slits at both ends, thereby manufacturing the buffer sheet. Therefore, the extruder die can be smaller than the width of the buffer sheet.

[0027] Furthermore, when unfolding a preform with a C-shaped or U-shaped cross-section that has been extruded, the main recess and the secondary recess are used as starting points. Therefore, even after unfolding a preform extruded into a C-shaped or U-shaped form using an extruder, the buffer sheet can be made into the desired shape. Attached Figure Description

[0028] Figure 1 This diagram shows a battery module with a buffer pad applied, indicating the state where the battery cells have not expanded.

[0029] Figure 2 Indicates in Figure 1 The battery cells in the battery module shown are in their maximum expansion state when fully charged.

[0030] Figure 3 This is a 3D view of the first example of a buffer sheet.

[0031] Figure 4is an enlarged front view of the cushion sheet of the first example, showing a reference state (state at the time of non-deformation).

[0032] Figure 5 is an enlarged front view of the cushion sheet of the first example, showing a state at the time of deformation.

[0033] Figure 6 is an enlarged front view of the cushion sheet of the second example, showing a reference state (state at the time of non-deformation).

[0034] Figure 7 is an enlarged front view of the cushion sheet of the second example, showing a state at the time of deformation.

[0035] Figure 8 is an enlarged front view of the cushion sheet of the third example, showing a reference state (state at the time of non-deformation).

[0036] Figure 9 is an enlarged front view of the cushion sheet of the fourth example, showing a reference state (state at the time of non-deformation).

[0037] Figure 10 is an enlarged front view of the cushion sheet of the fifth example, showing a reference state (state at the time of non-deformation).

[0038] Figure 11 is a perspective view of the cushion sheet of the sixth example.

[0039] Figure 12 is a perspective view of the cushion sheet of the seventh example.

[0040] Figure 13 is a flowchart showing a manufacturing method of the cushion sheet.

[0041] Figure 14 is a perspective view of the cushion sheet after extrusion molding.

[0042] Figure 15 is an enlarged front view of the cushion sheet after extrusion molding. DETAILED DESCRIPTION

[0043] (1. Applicable object of the cushion sheet)

[0044] The cushion sheet is interposed between a first member and a second member that face each other, and has a function of mitigating a load applied to the first member and the second member in a case where the first member and the second member approach each other. In particular, the cushion sheet takes a state in which the first member and the second member are in contact as a reference state, and exerts a cushioning function in a case where the first member and the second member approach from the reference state. The first member and the second member are only required to be objects that mitigate a load received, and can be arbitrary members. For example, the first member and the second member can be a housing formed of metal, resin, or the like.

[0045] (2. Examples of suitable applications for buffer sheets)

[0046] Battery module 1 is listed as an example of a suitable application for a buffer. (See reference...) Figure 1 as well as Figure 2 Battery module 1 will be described below. Battery module 1 can be used as an example to illustrate battery stacks in automotive and household lithium-ion rechargeable batteries and fuel cell systems.

[0047] The battery module 1 includes a stacked body 12 formed by stacking multiple battery cells 11, a binding member 13, a first buffer sheet 14, and a second buffer sheet 15. However, the battery module 1 is exemplified by having both the first buffer sheet 14 and the second buffer sheet 15, but it may also have a structure that only has either the first buffer sheet 14 or the second buffer sheet 15.

[0048] Each battery cell 11 constituting the stacked body 12 is, for example, formed into a flat cuboid shape. The stacked body 12 has the flat battery cells 11 stacked in a direction orthogonal to the direction of the flat surface (a direction normal to the flat surface).

[0049] The battery cell 11 includes a flat, rectangular box-shaped housing 11a and an electrode body 11b wound inside the housing 11a. The housing 11a is formed, for example, from a metal such as aluminum or a hard resin. Hereinafter, in the housing 11a, the surface orthogonal to the direction of the flat surface will be referred to as the object surface 11a1. The electrode body 11b includes a positive electrode, a negative electrode, and a separator sandwiched between the positive and negative electrodes, and is wound into a flat shape.

[0050] like Figure 2 As shown, the electrode body 11b heats up during charging, thus expanding primarily in the direction normal to the flat surface. The amount of expansion of the electrode body 11b decreases during discharging. Therefore, the casing 11a of the battery cell 11 housing the electrode body 11b expands in the direction normal to the flat surface during charging. In particular, since the casing 11a is formed into a flat box shape of a cuboid, the facing surface 11a1 is prone to expand and deform into a curved convex shape. The expansion of the facing surface 11a1 of the casing 11a is greatest when the battery cell 11 is fully charged. During discharging of the battery cell 11, as the expansion of the electrode body 11b decreases, the facing surface 11a1 of the casing 11a ideally returns to a flat shape. However, due to the deterioration of the electrode body 11b, it gradually becomes unable to return to its original shape, and the battery performance deteriorates.

[0051] The binding member 13 binds the laminate 12 from both ends in the lamination direction. That is, the binding member 13 acts by applying a reaction force to each battery cell 11 when each battery cell 11 expands due to charging, thereby causing the battery cell 11 to return to the reference state (unexpanded state).

[0052] The restraint member 13 includes, for example, a first restraint member 13a, a second restraint member 13b, and a connecting member 13c. The first restraint member 13a is L-shaped and is disposed on the pedestal portion of the laminate 12 and at the first end of the laminate 12 in the lamination direction supporting the laminate 12. Figure 1 The right side of the first binding member 13a (end binding portion). Specifically, the end binding portion of the first binding member 13a is arranged to face the object surface 11a1 of the battery cell 11 located at the first end of the stacking direction of the laminate 12. Further, in the end binding portion of the first binding member 13a, the surface facing the battery cell 11 is formed as a plane.

[0053] The second binding member 13b is formed in the shape of a flat plate and is disposed on the second end side opposite to the first end in the stacking direction of the laminate 12. Figure 1 (Left side). Specifically, the second binding member 13b is configured to face the object surface 11a1 of the battery cell 11 located at the second end of the stacking direction of the laminate 12. Further, in the second binding member 13b, the surface facing the battery cell 11 is formed as a plane.

[0054] Therefore, the laminate 12 is held in the lamination direction by the end binding portion of the first binding member 13a and the second binding member 13b. The connecting member 13c connects the end binding portion of the first binding member 13a to the second binding member 13b. To achieve sufficient binding force, the components 13a, 13b, and 13c constituting the binding member 13 are preferably made of metal, but rigid resin may also be used.

[0055] The first buffer sheet 14 is sandwiched between the object surface 11a1 of the battery cell 11 located at the second end of the stacking direction of the laminate 12 and the second binding member 13b. That is, the first buffer sheet 14 is sandwiched between the battery cell 11, which is one of the first member and the second member, and the second binding member 13b, which is the other of the first member and the second member.

[0056] The first buffer sheet 14 is formed of an elastic material, thereby absorbing deformation that occurs as the amount of expansion of the battery cell 11 increases or decreases. Furthermore, as... Figure 1 As shown, in the baseline state where the battery cell 11 is not expanded, the first buffer sheet 14 elastically supports the battery cell 11 by contacting the object surface 11a1 of the battery cell 11 and the second restraining member 13b. Further, as... Figure 2 As shown, the first buffer sheet 14 elastically supports the battery cell 11 when it expands during charging, and applies pressure to the battery cell 11 when the amount of expansion decreases during discharging.

[0057] The second buffer sheet 15 is sandwiched between the object faces 11al, 11al of the battery cells 11, 11 adjacent in the stacking direction. That is, the second buffer sheet 15 is sandwiched between the battery cell 11 of the adjacent one side as the first member and the battery cell 11 of the adjacent other side as the second member.

[0058] The second buffer sheet 15 is formed of an elastic material like the first buffer sheet 14, and absorbs deformation occurring in association with an increase and decrease in the expansion amount of the battery cell 11. Also, as shown in Figure 1 the reference state in which the battery cell 11 is not expanded, the second buffer sheet 15 elastically supports the battery cell 11 by contacting the object faces 11al, 11al of the opposing battery cells 11, 11. Further, as shown in Figure 2 the reference state in which the battery cell 11 is not expanded, the second buffer sheet 15 elastically supports the battery cell 11 by contacting the object faces 11al, 11al of the opposing battery cells 11, 11. Further, as shown in

[0059] Also, the more the number of the battery cells 11 constituting the stack 12, the greater the change in the overall length of the stack 12 occurring in association with an increase and decrease in the expansion amount of the battery cell 11. Therefore, in order to reliably absorb the change in the overall length of the stack 12, the first buffer sheet 14 and the second buffer sheet 15 appropriately function as described above.

[0060] In the present example, the first buffer sheet 14 and the second buffer sheet 15 have the same structure. However, the first buffer sheet 14 and the second buffer sheet 15 can have different structures.

[0061] The first buffer sheet 14 and the second buffer sheet 15 have a plurality of main support portions 21 that always contact the opposing first member and the second member to elastically support, and a linking portion 22 that links adjacent main support portions. As shown in Figure 1 and Figure 2 With expansion of the battery cell 11, the main support portion 21 mainly undergoes compression deformation. Also, the linking portion 22 is bent and deformed with compression deformation of the main support portion 21.

[0062] (3. Example of buffer sheet)

[0063] A specific example of the buffer sheet 14, the buffer sheet 15 will be described. Hereinafter, a first example to a seventh example of the buffer sheet 30, 40, 50, 60, 70, 80, 90 will be described.

[0064] (3-1. First example of buffer sheet 30)

[0065] (3-1-1. Structure of buffer sheet 30)

[0066] The structure of the first example of the buffer sheet 30 is described with reference toFigure 3 and Figure 4 The explanation will be made. As shown in Figure 3 , the cushion sheet 30 is formed in a shape (planar shape) extending in a planar direction parallel to the X-Y plane. The cushion sheet 30 is formed of an elastic material. For example, the cushion sheet 30 is formed of an elastic material in which resin or elastomer is a main material. The cushion sheet 30 preferably uses an elastomer excellent in elasticity in a low-temperature environment, such as EPDM.

[0067] The cushion sheet 30 can be formed of the same kind of elastic material throughout, or can be formed of a plurality of kinds of elastic materials. In the latter case, for example, in a thickness direction (Z direction) of the planar shape of the cushion sheet 30, different elastic materials can be applied to the front surface layer, the back surface layer, and the intermediate layer, respectively, or the same kind of material can be applied to the front surface layer and the back surface layer, and a different material can be applied to the intermediate layer.

[0068] The cushion sheet 30 has a plurality of main support portions 31 (corresponding to the main support portions 21 of Figure 1 and Figure 2 , and a plurality of link portions 32 (corresponding to the link portions 22 of Figure 1 and Figure 2 .

[0069] The main support portion 31 extends in a predetermined reference direction (Y direction) in the planar direction of the X-Y plane of the cushion sheet 30. That is, each main support portion 31 is formed of an elongated body extending in the Y direction. In particular, in the present example, as shown in Figure 3 , each main support portion 31 is formed of one elongated body extending over the entire length of the reference direction (Y direction) of the cushion sheet 30. Further, the plurality of main support portions 31 are arranged in parallel at equal intervals in the X direction.

[0070] As shown in Figure 4 , the main support portion 31 is formed in a narrow-head shape in a cross section orthogonal to the reference direction (Y direction) (a cross section parallel to the X-Z plane). The narrow-head shape includes a trapezoidal shape, a mountain shape in which the top end is curved convex, and the like. In the present example, the main support portion 31 is formed in an isosceles trapezoidal shape, but can be a non-isosceles trapezoidal shape.

[0071] The main support portion 31 is formed in a narrow-head shape having a wide surface 31a and a narrow surface 31b facing away from each other. The base end surface of the narrow-head shape becomes the wide surface 31a, and the top end surface becomes the narrow surface 31b. In the present example, the wide surface 31a and the narrow surface 31b are surfaces parallel to the X-Y plane. That is, the wide surface 31a and the narrow surface 31b are surfaces parallel to the planar direction of the cushion sheet 30.

[0072] Alternatively, it could be a curved surface protruding in the Z direction from a section orthogonal to the reference direction (Y direction) of the narrow surface 31b (a section parallel to the XZ plane). This structure is also included in structures where the wide surface 31a and the narrow surface 31b are surfaces parallel to the surface direction of the buffer sheet 30.

[0073] Furthermore, a main recess 31c extending in the reference direction (Y direction) is formed at the center of the width direction (X direction) of the wide surface 31a of the main support portion 31. The main recess 31c is formed throughout the entire length of the main support portion 31. The width of the main recess 31c is greatest at the opening and decreases towards the bottom. That is, the width of the main recess 31c gradually narrows in the depth direction.

[0074] like Figure 4 As shown, at least a portion of the wide surface 31a of the main support portion 31 is connected to the first member A (in Figure 1 The battery cell 11 or the second restraining member 13b) is in contact. In this example, a main recess 31c is formed in the wide surface 31a. Moreover, the main recess 31c opens on the side of the first member A. Therefore, the portion of the wide surface 31a of the main support portion 31, excluding the portion with the opening of the main recess 31c, is in contact with the first member A.

[0075] Furthermore, the narrow surface 31b of the main support portion 31 contacts the second member B. Here, no recess is formed in the narrow surface 31b. Therefore, the entire width of the narrow surface 31b contacts the second member B.

[0076] Thus, with the first component A and the second component B as the reference state (the furthest state), the main support portion 31 is configured to contact the first component A with its wide surface 31a and the second component B with its narrow surface 31b. For example... Figure 1 As shown, when the buffer sheet 30 is applied to the battery module 1, in the reference state where the battery cell 11 is not expanded, the wide surface 31a contacts one of the components of the battery cell 11 and the second restraining member 13b, and the narrow surface 31b contacts the other component of the battery cell 11 and the second restraining member 13b.

[0077] The connecting portion 32 is formed in a strip shape, connecting adjacent main support portions 31, 31. Both ends of the connecting portion 32 in the bandwidth direction are connected to the adjacent main support portions 31, 31. The connecting portion 32 is formed in a flat shape parallel to the XY plane. That is, in its non-deformed state, both flat surfaces of the connecting portion 32 are formed as planar. The bandwidth of the connecting portion 32 is, for example, formed to be the same as the width of the wide surface 31a of the main support portion 31.

[0078] The thickness (Z-direction thickness) of the linking portion 32 is sufficiently small compared with the height (Z-direction height) of the main support portion 31. Also, the linking portion 32 links the wide surface 31a side of the inclined side surface (e.g., trapezoidal waist surface) of the narrow head shape in the adjacent main support portions 31, 31. More specifically, one surface (first member A side surface) of the linking portion 32 is on the same plane as the wide surface 31a of the main support portion 31. On the other hand, the other surface (second member B side surface) of the linking portion 32 is on a position closer to the first member A side than the narrow surface 31b of the main support portion 31. That is, the main support portion 31 and the linking portion 32 are in a positional relationship in which the main support portion 31 protrudes toward the second member B side from the linking portion 32.

[0079] That is, in a case where the first member A and the second member B are in a reference state (most distant state), the linking portion 32 is arranged in a state in which one surface is in contact with the first member A and the other surface has a distance from the second member B.

[0080] Here, the linking portion 32 is formed in a shape that allows deformation. The linking portion 32 can be deformed in a manner in which the distance between both ends in the tape width direction becomes shorter. For example, the linking portion 32 is bent and deformed by being pressed in the tape width direction.

[0081] The sub recesses 33, 34 are formed at the boundary portion of the main support portion 31 and the linking portion 32. In the present example, the sub recesses 33, 34 are formed at the boundary portion of the second member B side surface of the linking portion 32 and the inclined side surface of the main support portion 31. That is, the sub recesses 33, 34 open on the second member B side. The sub recesses 33, 34 extend in the reference direction (Y-direction). In the present example, the sub recesses 33, 34 are formed over the entire length of the main support portion 31. In addition, the opening width of the sub recesses 33, 34 is smaller than the opening width of the main recess 31c. Further, the depth from the opening of the sub recesses 33, 34 is shallower than the depth from the opening of the main recess 31c.

[0082] (3-1-2. Action of the cushion sheet 30)

[0083] Next, the action of the cushion sheet 30 of the first example will be described with reference to Figure 4 and Figure 5 In a case where the interval distance between the first member A and the second member B becomes shorter, the cushion sheet 30 is deformed as shown in Figure 5 Here, in Figure 5 , a case is illustrated in which the first member A and the second member B are in a state in which the interval distance is made shorter while being kept parallel. However, the interval distance between the first member A and the second member B is not limited to this case.

[0084] In a case where the interval distance between the first member A and the second member B becomes shorter, the main support portion 31 is compressed and deformed. In particular, since the main support portion 31 has the main recessed portion 31c which is open toward the first member A side, the inclined waist portions on both sides in the width direction of the main support portion 31 are compressed and deformed. That is, the main support portion 31 is deformed in the height direction (Z direction) in such a manner that the volume of the main recessed portion 31c is reduced. In this way, the main recessed portion 31c functions as a region which absorbs the deformation of the main support portion 31.

[0085] Further, the sub recessed portions 33, 34 are formed at the boundary portions of the main support portion 31 and the linking portion 32. Therefore, in a case where the interval distance between the first member A and the second member B becomes shorter, the sub recessed portions 33, 34, in addition to the main recessed portion 31c, function as regions which absorb the deformation of the main support portion 31.

[0086] Further, the cross section of the main support portion 31 is a narrow head shape (for example, a trapezoidal shape), and the main recessed portion 31c is formed at the wide face 31a side. Further, the linking portion 32 is allowed to be compressed in the width direction. Therefore, in a case where the interval distance between the first member A and the second member B becomes shorter, the main support portion 31 is deformed in such a manner that the width (X direction width) of the wide face 31a is enlarged in the width direction. That is, the main support portion 31 is deformed in such a manner that the height is lowered in the cross section parallel to the X-Z plane, and the width of the wide face 31a is enlarged. Therefore, the adjacent spaces of the inclined side faces (for example, trapezoidal waist faces) of the main support portion 31 function as regions which absorb the deformation of the main support portion 31.

[0087] As described above, the main recessed portion 31c, the sub recessed portions 33, 34, and the adjacent spaces of the inclined side faces (for example, trapezoidal waist faces) of the main support portion 31 function as regions which absorb the deformation of the main support portion 31. As a result, it is possible to increase the amount of deformation in the height direction of the main support portion 31. That is, it is possible to shorten the interval distance between the first member A and the second member B. Here, compared to a case where only the main recessed portion 31c functions as a region which absorbs the deformation of the main support portion 31, it is not possible to become a state where the main recessed portion 31c is excessively large. That is, it is not a configuration where only the main recessed portion 31c functions as a region which absorbs the deformation of the main support portion 31, and therefore it is possible to secure the rigidity of the inclined waist portions on both sides in the width direction of the main support portion 31, and as a result it is possible to sufficiently secure the support force of the main support portion 31.

[0088] As described above, by forming the main recessed portion 31c at the wide face 31a side of the main support portion 31, in a case where the interval distance between the first member A and the second member B becomes shorter, the main support portion 31 is deformed in such a manner that the width of the wide face 31a is enlarged. As a result, the linking portion 32 receives a compressive load in the width direction (X direction) of the linking portion 32 from the adjacent main support portion 31.

[0089] At this time, the linking portion 32 is easily bent in the width direction with the sub recessed portions 33, 34 as a starting point. That is, as shown in Figure 5 the linking portion 32 is bent and deformed to a convex shape with the sub recessed portions 33, 34 as a starting point to the second member B side as the width surface 31a of the main support portion 31 expands. More specifically, the linking portion 32 is bent and deformed to a convex shape to the second member B side with the deformation of the opening width of the sub recessed portions 33, 34 as a starting point.

[0090] More specifically, with the deformation of the main support portion 31, the cross section of the linking portion 32 in the width direction (X direction) is bent and deformed to a convex shape with the sub recessed portions 33, 34 as a starting point to the second member B side. That is, the sub recessed portions 33, 34 are formed on the side where the linking portion 32 is bent, and thus the sub recessed portions 33, 34 effectively function as a starting point of the deformation of the linking portion 32. Furthermore, with the bending deformation of the linking portion 32, the main support portion 31 can be further deformed in the surface direction (X direction), and the amount of deformation in the height direction of the main support portion 31 can be increased.

[0091] The surface of the linking portion 32 on the first member A side is deformed to a curved concave shape to form a space with the first member A. On the other hand, the surface of the linking portion 32 on the second member B side is deformed to a curved convex shape to approach the second member B. In the state where the linking portion 32 is bent and deformed to a convex shape, the surface of the linking portion 32 on the second member B side can be in contact with the second member B, or can not be in contact with the second member B. In the case where the linking portion 32 is in contact with the second member B, the linking portion 32 presses the second member B. That is, the linking portion 32 functions as a support force. In this way, by utilizing the support force of the linking portion 32, the support force characteristics of the cushion sheet 30 can be freely designed.

[0092] Here, for example, in the battery module 1 shown in Figure 1 the cushion sheet 30 can be designed based on the maximum amount of expansion at the time of full charge of the battery cell 11. At the time of full charge of the battery cell 11, the surface of the linking portion 32 on the second member B side can be in contact with the second member B, or can not be in contact with the second member B. In addition, at the time of full charge of the battery cell 11, in the cross section parallel to the X-Z direction, the space area formed by the linking portion 32 after the bending deformation and the first member A can be designed to be larger than the area of the main recessed portion 31c.

[0093] (3-2. Second Example of Cushion Sheet 40)

[0094] Reference will be made to Figure 6 and Figure 7 the second example of the cushion sheet 40 will be described. In the second example of the cushion sheet 40, the same reference numerals are attached to the same structures as those of the first example of the cushion sheet 30, and the description thereof will be omitted.

[0095] As shown in Figure 6As shown, the buffer sheet 40 includes multiple main support portions 31 and multiple connecting portions 42. The main support portions 31 have the same structure as the main support portion 31 in the first example. The connecting portion 42 includes a connecting portion body 42a and a small protrusion 42b. The connecting portion body 42a has the same structure as the connecting portion 32 in the first example. The small protrusion 42b is formed on the surface of the connecting portion body 42a on the side of the second member B, and has a protrusion height smaller than the protrusion height of the main support portions 31. The small protrusion 42b is formed at the center of the connecting portion body 42a in the bandwidth direction.

[0096] When the distance between the first component A and the second component B becomes shorter, such as Figure 7 As shown, the main support portion 31 deforms. As the main support portion 31 deforms, the connecting portion body 42a undergoes bending deformation. At this time, the surface of the connecting portion body 42a on the second member B side bends and deforms in a convex manner. If the deformation of the connecting portion body 42a increases, the small protrusion 42b contacts the second member B and undergoes compressive deformation. That is, by performing compressive deformation through the small protrusion 42b, the support force characteristics of the buffer sheet 40 can be freely designed.

[0097] (3-3. Buffer sheet 50 in the third example)

[0098] Reference Figure 8 The third example of the buffer sheet 50 will be described. In the third example of the buffer sheet 50, the same reference numerals are used for structures identical to those in the first example of the buffer sheet 30, and descriptions are omitted. Figure 8 As shown, the buffer sheet 50 has multiple main support portions 31 and multiple connecting portions 32. The main support portions 31 and connecting portions 32 have the same structure as the main support portions 31 and connecting portions 32 in the first example.

[0099] In the buffer sheet 50, secondary recesses 53 and 54 are formed at the boundary between the main support portion 31 and the connecting portion 32. In this example, the secondary recesses 53 and 54 are formed at the boundary between the surface of the connecting portion 32 on the first member A side and the wide surface 31a of the main support portion 31. That is, the secondary recesses 53 and 54 are open on the first member A side. The secondary recesses 53 and 54 extend in the reference direction (Y direction). In this example, the secondary recesses 53 and 54 are formed along the entire length of the main support portion 31. In addition, the opening width of the secondary recesses 53 and 54 is smaller than the opening width of the main recess 31c. Furthermore, the depth of the secondary recesses 53 and 54 from the opening is shallower than the depth of the main recess 31c from the opening.

[0100] When the distance between the first member A and the second member B decreases, the main support portion 31 deforms in such a way that the width of the wide surface 31a increases. As a result, the connecting portion 32 bears a compressive load from the adjacent main support portion 31 in the bandwidth direction (X direction) of the connecting portion 32.

[0101] At this time, the linking portion 32 is easily bent in the width direction from the sub recessed portions 53, 54 as a starting point. That is, as shown in FIG. 6, the linking portion 32 is bent and deformed to be convex toward the second member B side from the sub recessed portions 53, 54 as a starting point with the expansion of the wide face 31a of the main support portion 31. More specifically, the linking portion 32 is bent and deformed to be convex toward the second member B side from the deformation of the opening width of the sub recessed portions 53, 54 as a starting point. Figure 8

[0102] (3-4. Fourth Example of the Buffer Sheet 60)

[0103] Referring to Figure 9 The fourth example of the buffer sheet 60 will be described. In the fourth example of the buffer sheet 60, the same reference numerals are attached to the same structures as those of the first example of the buffer sheet 30, and the description thereof will be omitted. As shown in FIG. 7, the buffer sheet 60 is provided with a plurality of main support portions 31, a plurality of linking portions 32, and a pair of outer support portions 65, 65. The main support portions 31 and the linking portions 32 have the same structures as those of the first example of the main support portion 31 and the linking portion 32. Figure 9

[0104] The pair of outer support portions 65, 65 is located on both outer sides in the direction in which the plurality of main support portions 31 are arranged in parallel. The outer support portion 65 is linked with the main support portions 31 at both ends via the linking portion 32. Further, the outer support portion 65 extends in the reference direction (Y direction). That is, the outer support portion 65 extends in a direction parallel to the main support portion 31. The outer support portions 65, 65 are each formed of one long strip extending over the entire length of the buffer sheet 60 in the reference direction (Y direction), like the main support portion 31.

[0105] In a cross section orthogonal to the reference direction (Y direction) (a cross section parallel to the X-Z plane), the outer support portion 65 is formed in a narrow head shape (for example, a trapezoidal shape) similar to the main support portion 31. In the present example, the outer support portion 65 is formed in an isosceles trapezoidal shape, but can be a non-isosceles trapezoidal shape.

[0106] More specifically, the outer support portion 65 is formed in a narrow head shape having a wide face 65a and a narrow face 65b facing away from each other. A part of the wide face 65a is in contact with the first member A, and the narrow face 65b is in contact with the second member B. The height of the outer support portion 65, that is, the distance between the wide face 65a and the narrow face 65b, is formed to be higher than the height of the main support portion 31. That is, the outer support portion 65 is higher in protrusion height than the main support portion 31.

[0107] Further, the outer support portion 65 has a recessed portion 65c, like the main support portion 31. The recessed portion 65c of the outer support portion 65 can be provided in the same shape as the main recessed portion 31c of the main support portion 31, or in a different shape from the main recessed portion 31c. ​​

[0108] For example, when set as the application object of buffer 60 Figure 1 as well as Figure 2 In the case of the battery module 1 shown, considering the expansion and deformation shape of the battery module 1, the central portion of the buffer sheet 60 in the sheet width direction ( Figure 9 The deformation in the thickness direction is increased at the central part in the left and right directions, and the deformation at both ends in the width direction of the buffer sheet 60 is increased. Figure 9 The deformation in the thickness direction can be reduced by decreasing the deformation at both ends in the left and right directions.

[0109] Therefore, the outer support portion 65 is located at both ends where the expansion deformation is small, and the main support portion 31 is located at the center where the expansion deformation is large. Thus, the buffer sheet 60 can exert appropriate supporting force according to the expansion deformation of the battery module 1.

[0110] (3-5. Buffer sheet 70 in the fifth example)

[0111] Reference Figure 10 The fifth example of the buffer sheet 70 will be described. In the fifth example of the buffer sheet 70, the same reference numerals are used for structures identical to those in the first example of the buffer sheet 30, and descriptions are omitted. Figure 10 As shown, the buffer sheet 70 includes multiple main support portions 31, multiple connecting portions 32, and one pair of outer support portions 75, 75. The main support portions 31 and connecting portions 32 have the same structure as the main support portions 31 and connecting portions 32 in the first example.

[0112] One set of outer support portions 75, 75 is located on both outer sides of the plurality of main support portions 31 in a parallel direction. The outer support portion 75 is connected to the main support portions 31 at both ends via a connecting portion 32. Furthermore, the outer support portion 75 extends in a reference direction (Y direction). That is, the outer support portion 75 extends in a direction parallel to the main support portions 31. The outer support portions 75, 75 are each formed, like the main support portions 31, as a long strip extending along the entire length of the buffer sheet 70 in the reference direction (Y direction).

[0113] The outer support portion 75 is formed in a cross section orthogonal to the reference direction (Y direction) (a cross section parallel to the XZ plane) with the same narrow-head shape as the main support portion 31 (e.g., trapezoidal). In this example, the outer support portion 75 is formed as an isosceles trapezoid, but it could also be an isosceles trapezoid.

[0114] In detail, the outer support portion 75 is formed into a narrow-head shape having a wide surface 75a and a narrow surface 75b facing each other. However, the outer support portion 75 does not have recesses at either the wide surface 75a or the narrow surface 75b. Moreover, the entire surface of the wide surface 75a contacts the first member A, and the entire surface of the narrow surface 75b contacts the second member B. The height of the outer support portion 75, i.e., the distance between the wide surface 75a and the narrow surface 75b, is the same as the height of the main support portion 31.

[0115] For example, in the case of the battery module 1 shown in FIG. 1, the sheet width direction central portion (the left-right direction central portion of the sheet 70) of the buffer sheet 70 is increased in thickness direction deformation amount, and the sheet width direction both end portions (the left-right direction both end portions of the sheet 70) are decreased in thickness direction deformation amount. Figure 1 Figure 2 Figure 10 Figure 10

[0116] Therefore, the outer support portion 75 is located at both ends where the expansion deformation amount is small, and the main support portion 31 is located at the central portion where the expansion deformation amount is large. The outer support portion 75 is allowed to have a smaller deformation amount than the main support portion 31 by a corresponding amount that the main recess portion 31c does not have. Therefore, the buffer sheet 70 can exert an appropriate support force in accordance with the expansion deformation amount of the battery module 1.

[0117] (3-6. Buffer sheet 80 of the sixth example)

[0118] Referring to Figure 11 The buffer sheet 80 of the sixth example will be described. In the buffer sheet 80 of the sixth example, the same reference numerals are attached to the same structures as those of the buffer sheet 30 of the first example, and the description thereof will be omitted. As shown in FIG. 8, the buffer sheet 80 is provided with a plurality of main support portions 81 and a plurality of link portions 32. Figure 11

[0119] In the buffer sheet 30 of the first example, each main support portion 31 is formed of one long strip extending over the entire length of the buffer sheet 30 in the reference direction (Y direction). On the other hand, in the buffer sheet 80 of the sixth example, each main support portion 81 is formed of a plurality of long strips 81a, 81b, 81c at predetermined intervals in the reference direction (Y direction).

[0120] The main support portion 81 is formed in the same narrow head shape (for example, a trapezoidal shape) as the main support portion 31 of the first example in a cross section orthogonal to the reference direction (Y direction) (a cross section parallel to the X-Z plane). That is, the main support portion 81 has a wide face 31a and a narrow face 31b, and is formed with a main recess portion 31c.

[0121] In addition, the main recess portion 31c and the sub recess portions 33, 34 are formed over the entire length of the buffer sheet 80. That is, the main recess portion 31c and the sub recess portions 33, 34 are also formed at positions where the long strips constituting the main support portion 81 are not present. However, the main recess portion 31c and the sub recess portions 33, 34 can be formed only at positions where the long strips constituting the main support portion 81 are present.

[0122] (3-7. Buffer sheet 90 of the seventh example)

[0123] Referring to​​​​​Figure 12 The seventh example, buffer sheet 90, will be described. In the seventh example, buffer sheet 90 uses the same reference numerals as the buffer sheet 30 in the first example, and descriptions are omitted. For example... Figure 12 As shown, the buffer sheet 90 includes multiple main support portions 31, multiple connecting portions 32, and an outer frame portion 95. The main support portions 31 and connecting portions 32 have the same structure as the main support portions 31 and connecting portions 32 in the first example.

[0124] The outer frame portion 95 is formed around the entire outer periphery of the buffer sheet 90 and is filled with an elastic material. The cross-sectional shape of the outer frame portion 95, which is orthogonal to the extending direction, can be any shape, such as a rectangle, trapezoid, or mountain shape. The outer frame portion 95 performs the same function as the outer support portion 75 in the buffer sheet 70 of the fifth example.

[0125] (4. Manufacturing method of buffer sheet)

[0126] (4-1. Examples of methods for manufacturing buffer sheets)

[0127] Reference Figures 13-15 An example of a method for manufacturing a buffer sheet will be described. The manufacturing method described below can be applied to buffer sheets 30, 40, 50, 60, and 70 of the first to fifth examples described above. Hereinafter, buffer sheet 30 of the first example will be used as an example.

[0128] First, an elastic material, primarily composed of resin or elastomer, is formed using an extruder (not shown). Figure 14 as well as Figure 15 The preform 100 shown Figure 13 Step S1: Extrusion molding process). The preform 100 is aligned with the reference direction (Y direction) by extrusion direction, and the cross-sectional shape orthogonal to the extrusion direction is formed into a C-shape or U-shape. Figure 14 as well as Figure 15 This refers to the case where the cross-sectional shape is C-shaped. That is, the preform 100 has a C-shaped or U-shaped break along its entire length, i.e., a slit 101.

[0129] Here, in this example, as Figure 14 as well as Figure 15 As shown, the preform 100 is extruded into a C-shape or U-shape with the main recess 31c located radially outward. That is, the protruding direction of the main support portion 31 faces radially inward. In this case, in the buffer sheets 30, 40, 60, and 70 of the first, second, fourth, and fifth examples, the preform 100 is extruded into a C-shape or U-shape with the secondary recesses 33 and 34 located radially inward. In addition, in the buffer sheet 50 of the third example, the preform 100 is extruded into a C-shape or U-shape with the secondary recesses 53 and 54 located radially outward.

[0130] In addition to the above, the preform 100 can be extrusion-molded in a C shape or a U shape with the main recessed portion 31c positioned on the radially inner side. That is, the protruding direction of the main support portion 31 is toward the radially outer side. In this case, in the cushioning sheet 30, 40, 60, 70 of the first example, the second example, the fourth example, and the fifth example, the preform 100 is extrusion-molded in a C shape or a U shape with the sub recessed portions 33, 34 positioned on the radially outer side. In addition, in the cushioning sheet 50 of the third example, the preform 100 is extrusion-molded in a C shape or a U shape with the sub recessed portions 53, 54 positioned on the radially inner side.

[0131] Next, the preform 100 after extrusion molding is expanded in a C shape or a U shape with the slit becoming both ends (step S2: expansion process). At this time, the preform 100 is expanded from the main recessed portion 31c and the sub recessed portions 33, 34, 53, 54. Therefore, expansion can be easily performed. Next, the preform 100 in the expanded state is vulcanized by a vulcanization device, thereby manufacturing the cushioning sheet 30, 40, 50, 60, 70 (step S3: vulcanization process). Figure 13 Figure 13

[0132] Suppose that, in a case where a flat plate-shaped cushioning sheet 30 or the like is extrusion-molded by an extruder, the maximum width of the die of the extruder needs to be equal to or greater than the width of the cushioning sheet 30 or the like. Therefore, if the width of the cushioning sheet 30 or the like becomes large, the die of the extruder becomes large. However, in the manufacturing method described above, the cross-sectional shape orthogonal to the extrusion direction is extrusion-molded in a C shape or a U shape, and then expanded in a C shape or a U shape with the slit becoming both ends, thereby manufacturing the cushioning sheet 30 or the like. Therefore, the die of the extruder can be smaller than the width of the cushioning sheet 30 or the like.

[0133] In addition, when the preform 100 having the extrusion-molded C shape or U shape cross-sectional shape is expanded, the main recessed portion 31c and the sub recessed portions 33, 34, 53, 54 are the starting points. Therefore, even if expanded after extrusion-molded in a C shape or a U shape by the extruder, the cushioning sheet 30 or the like can be made into a desired shape.

[0134] Here, in a case where the protruding direction of the main support portion 31 is set to the radially inner side in the preform 100, the protruding portion of the main support portion 31 can be accommodated in the area surrounded by the connecting portion 32 and the portion of the main support portion 31 on the wide surface 31a side. Therefore, the width of the preform 100 can be further reduced.

[0135] ​​Further, in the cushioning sheet 30, 40, 60, 70, the preform 100 is expanded and deformed by the main recessed portion 31c and the sub recessed portion 33, 34. That is, the main recessed portion 31c and the sub recessed portion 33, 34 easily function as a starting point of the expansion and deformation. As a result, the preform 100 can be easily unfolded from the C shape or the U shape.

[0136] Further, in the cushioning sheet 50, the main recessed portion 31c and the sub recessed portion 53, 54 of the preform 100 can be opened to the radial inner side. In this case, the preform 100 is unfolded by the main recessed portion 31c and the sub recessed portion 53, 54 being expanded and deformed. That is, the main recessed portion 31c and the sub recessed portion 53, 54 easily function as a starting point of the expansion and deformation. As a result, the preform 100 can be easily unfolded from the C shape or the U shape.

[0137] (4-2. Other manufacturing method)

[0138] The cushioning sheets 80, 90 of the sixth and seventh examples are not the same in the cross section orthogonal to the reference direction (the cross section parallel to the X-Z plane) over the entire length in the reference direction (Y direction), and thus it is not easy to apply extrusion molding to shape. Therefore, the cushioning sheets 80, 90 can be manufactured by injection molding. Furthermore, the other cushioning sheets 30-70 can also be manufactured by injection molding.

Claims

1. A buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90), formed of an elastic material, and sandwiched between opposing first members (A) and second members (B), wherein, The buffer sheets (14, 15, 30, 40, 50, 60, 70, 80, 90) have the following features: Multiple main support portions (21, 31, 81) extend in a predetermined reference direction in the surface direction of the buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90), and are formed into a narrow-head shape having a wide facet (31a) and a narrow facet (31b) facing each other in a cross section orthogonal to the reference direction, and are arranged in a state where at least a portion of the wide facet (31a) is in contact with the first member (A) and the narrow facet (31b) is in contact with the second member (B); as well as The strip-shaped connecting portions (22, 32, 42) connect the wide surface (31a) side of the narrow-headed inclined side to each other in adjacent main support portions (21, 31, 81), and are arranged in a state of contact with the first member (A) and a state of distance from the second member (B). In the central portion of the narrow-head shape in the wide surface (31a) of the main support portion (21, 31, 81), a main recess (31c) extending in the reference direction and opening on the side of the first member (A) is formed. At the boundary between the main support portion (21, 31, 81) and the connecting portion (22, 32, 42), a secondary recess (33, 34, 53, 54) is formed, extending in the reference direction and opening on at least one side of the first member (A) and the second member (B), with an opening width smaller than that of the main recess (31c).

2. The buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90) according to claim 1, wherein, The depth of the secondary recesses (33, 34, 53, 54) from the opening is shallower than the depth of the main recess (31c) from the opening.

3. The buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90) according to claim 1 or 2, wherein, When the distance between the first component (A) and the second component (B) becomes shorter, the main support portion (21, 31, 81) undergoes compression deformation and deforms in such a way that the width of the wide surface (31a) expands in the width direction. As the main support portion (21, 31, 81) deforms, starting from the secondary recess (33, 34, 53, 54), the cross section of the connecting portion (22, 32, 42) in the bandwidth direction bends and deforms into a convex shape towards the second component (B).

4. The buffer sheet (50) according to claim 3, wherein, The secondary recesses (53, 54) open on the side of the first member (A). The connecting portion (32) is bent and deformed into the convex shape, starting from the deformation caused by the change in the opening width of the secondary recess (53, 54).

5. The buffer sheet (30, 40, 60, 70) according to claim 3, wherein, The secondary recesses (33, 34) open on the side of the second member (B). The connecting portion (32, 42) bends and deforms into the convex shape, starting from the deformation caused by the change in the opening width of the secondary recess (33, 34).

6. The buffer sheet (30, 40, 50, 60, 70) according to claim 3, wherein, When bent and deformed into the convex shape, the connecting parts (22, 32, 42) press against the second member (B).

7. The buffer sheet (40) according to claim 6, wherein, The connecting portion (42) has a small protrusion (42b) on the side of the second member (B) that is smaller in height than the main support portion (31). With the connecting part (42) bent and deformed into the convex shape, the small protrusion (42b) presses against the second member (B).

8. The buffer sheet (30, 50, 60, 70) according to claim 6, wherein, The surface of the second member (B) side of the connecting part (32) is planar in the non-deformable state. When the bending deformation is in the convex state, the surface of the connecting part (32) on the second member (B) side presses against the second member (B).

9. The buffer sheet (60) according to claim 1 or 2, wherein, The buffer sheet (60) also includes an outer support portion (65) located on both sides of the plurality of main supports (31) and connected to the main supports (31) at both ends via the connecting portion (32). The outer support portion (65) extends in the reference direction and is formed into a narrow head shape having a wide facet (65a) and a narrow facet (65b) facing each other in a cross section orthogonal to the reference direction. The outer support portion (65) is configured such that at least a portion of the wide facet (65a) is in contact with the first member (A) and the narrow facet (65b) is in contact with the second member (B). The protrusion height of the outer support portion (65) is greater than the protrusion height of the main supports (31).

10. The buffer sheet (70) according to claim 1 or 2, wherein, The buffer sheet (70) also includes an outer support portion (75), which is located on both sides of the plurality of main support portions (31) and is connected to the main support portions (31) at both ends via the connecting portion (32). The outer support portion (75) extends in the reference direction and is formed into a narrow head shape having a wide face (75a) and a narrow face (75b) facing each other in a cross section orthogonal to the reference direction. The outer support portion (75) is configured such that the entire surface of the wide face (75a) is in contact with the first member (A) and the entire surface of the narrow face (75b) is in contact with the second member (B).

11. The buffer sheet (30, 40, 50, 60, 70, 90) according to claim 1 or 2, wherein, Each of the main support portions (31) is formed by an elongated body extending in the reference direction.

12. The buffer sheet (80) according to claim 1 or 2, wherein, Each of the main support portions (81) is formed by multiple elongated bodies (81a, 81b, 81c) spaced apart at predetermined intervals in the reference direction.

13. The buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90) according to claim 1 or 2, wherein, The buffer sheets (14, 15, 30, 40, 50, 60, 70, 80, 90) are applied to the battery module (1), which has a stack (12) of multiple battery cells (11) and binding members (13a, 13b) binding the stack (12) from both ends of the stack (12) in the stacking direction. The first component (A) and the second component (B) are opposite battery cells (11) and restraint components (13a, 13b), or two opposite battery cells (11).

14. The buffer sheet (30, 40, 50, 60, 70) according to claim 3, wherein, The buffer sheets (30, 40, 50, 60, 70) are applied to the battery module (1), which has a stack (12) of multiple battery cells (11) and binding members (13a, 13b) that bind the stack (12) from both ends of the stack (12) in the stacking direction. The first component (A) and the second component (B) are opposite battery cells (11) and restraint components (13a, 13b), or two opposite battery cells (11). When the plurality of battery cells (11) are fully charged, in a cross section orthogonal to the reference direction, the area of ​​the space formed by the bent and deformed connecting portions (32, 42) and the first member (A) is larger than the area of ​​the main recess (31c).

15. A method for manufacturing a buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90), which is the method for manufacturing the buffer sheet (14, 15, 30, 40, 50, 60, 70, 80, 90) according to any one of claims 1 to 14, wherein, In the manufacturing method, Using an elastic material primarily composed of resin or elastomer, an extruder is used to align the extrusion direction with the reference direction, extruding a cross-sectional shape orthogonal to the extrusion direction into a C-shape or U-shape. Starting from the main recess (31c) and the secondary recesses (33, 34, 53, 54), the extrusion is carried out with the C-shaped or U-shaped slits obtained by extrusion forming as the two ends.

16. The method for manufacturing the buffer sheets (30, 40, 60, 70, 80, 90) according to claim 15, wherein, The main recess (31c) is extruded into the C-shape or the U-shape with the main recess (31c) located on the radially outer side.

17. The method for manufacturing the buffer sheets (30, 40, 60, 70, 80, 90) according to claim 16, wherein, The secondary recesses (33, 34) open on the side of the second member (B). The main recess (31c) is located radially outward and the secondary recesses (33, 34) are located radially inward, so that they are extruded into the C-shape or the U-shape.

18. The method for manufacturing the buffer sheet (50) according to claim 15, wherein, The secondary recesses (53, 54) open on the side of the first member (A). The main recess (31c) is located radially inward and the secondary recesses (53, 54) are located radially inward, and the C-shape or U-shape is formed by extrusion.

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