Buffer material for battery, and battery

Abstract

A battery buffer material (1) includes a composite body (2) of a base material (2a) formed from a fiber material and a rubber (2b) impregnated into the base material (2a), and pores (3) are present in the composite body (2). This buffer material (1) for batteries can stably function as a buffer material and as a storage battery.

Description

Technical Field

[0001] The present invention relates to a buffer material for a battery and a battery. Background Art

[0002] In automobiles, motorcycles, ships, household fuel cells, etc., battery packs (battery modules) formed by stacking single cells (battery units) are effectively utilized. As rechargeable secondary batteries, in addition to lithium-ion batteries that have been widely sold, there are also all-solid-state batteries that do not use an electrolyte and thus do not have a liquid junction between battery units, bipolar nickel-metal hydride batteries that have a lower risk of abnormal power generation compared to lithium-ion batteries, lead-acid batteries, and the like.

[0003] These secondary batteries repeatedly expand / contract during charge and discharge. Due to recent increases in the charge amount and lifespan, the degree of expansion / contraction during charge and discharge has become larger, and the number of repetitions of expansion / contraction has also increased. In order to achieve stable battery performance and long lifespan, it is necessary to appropriately maintain the pushing pressure between the stacked single cells (the pressure caused by the expansion of each single cell and the pushing caused by the reaction force from other single cells, hereinafter also simply referred to as "pressure"). For example, it is required that during expansion, excessive pressure is not applied to each single cell, and during contraction, pressure is applied to the extent that each single cell is appropriately fixed / held.

[0004] For example, Patent Document 1 proposes a fireproof sheet having a pair of fireproof materials and an elastic member disposed therebetween. The cushioning property of this disaster prevention sheet is obtained by an elastic member composed of a rubber sheet or the like. However, the cushioning property of a flat rubber sheet is insufficient. This is because it cannot follow the deformation caused by the expansion / contraction of the battery. Thus, in Patent Document 2, as a buffer material for applying appropriate pressure between single cells, a rubber sheet having a concavo-convex shape is proposed. Figure 16 is a perspective view showing a conventional buffer material for a battery module. As Figure 16 shown, the buffer material 200 for a battery module in Patent Document 1 is a sheet obtained by forming a rubber into a concavo-convex shape 202 with a relatively thick rim 201 at the outer periphery of the sheet.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-117936

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2022-119556 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In the case of the rubber sheet disclosed in Patent Document 2, the uneven portions of the rubber sheet are repeatedly deformed due to expansion / contraction caused by charge / discharge. The uneven portions of the rubber sheet are deteriorated due to repeated deformation and heat generation of the battery. In particular, stress is concentrated on the corner portion where the convex portion protrudes from the base portion, and cracks are likely to occur. If cracks occur, the cushioning property deteriorates, and sufficient pressure cannot be applied for fixing / holding each single cell during contraction. This problem is particularly significant when the number of repeated expansions / contractions increases with the long life of the battery. In addition, the deteriorated cushioning material cannot exhibit its original function, and stable holding of each single cell cannot be achieved during contraction.

[0011] Therefore, one object of the present invention is to provide a cushioning material for a battery that can stably exhibit its function as a cushioning material and a battery using the same.

[0012] Means for Solving the Problems

[0013] The present inventors conducted intensive studies to achieve the above object, and as a result, obtained the following insights.

[0014] For the cushioning material, it is required to be sufficiently compressed during expansion of the single cell and sufficiently restored during contraction of the single cell. Thus, during expansion and contraction of the single cell, an appropriate pressure can be continuously applied to the single cell.

[0015] Here, in the case of a cushioning material that requires a large force for compression during expansion of the single cell, the expansion of each single cell is hindered, and the battery performance deteriorates. Therefore, for the cushioning material, it is required to sufficiently contract even with a small pressure. In this regard, if a relatively soft rubber (for example, a rubber containing a large number of pores) is used or a cushioning material provided with unevenness is used, it is easy to satisfy this requirement. However, the cushioning material obtained using a rubber sheet is likely to be deformed in a direction perpendicular to the compression direction ( Figure 14 the left-right direction) ( Figure 14 the up-down direction) during expansion of the single cell, and thus, it is difficult to apply an appropriate pressure to the single cell. In addition, the cushioning material of the soft rubber sheet is likely to be deteriorated, and the restoration during contraction of the single cell becomes insufficient due to repeated use. That is, it is difficult for such a cushioning material to stably exhibit its function as a cushioning material.

[0016] Therefore, the present inventors studied a cushioning material in which rubber is impregnated in a fiber material. That is, the fiber material contains a large number of pores and originally has a certain degree of cushioning property. And the composite in which rubber is impregnated in the fiber material has an appropriate number of pores, and is more likely to contract under a small pressure (that is, has excellent cushioning property) compared with the cushioning material obtained using a rubber sheet. And since such a cushioning material has a fiber material, it is possible to suppress the cushioning material from deforming in a direction perpendicular to the compression direction ( Figure 14 the left-right direction) ( Figure 14The deformation occurring in the vertical direction). Therefore, an appropriate pressure can be applied to the single cell. In addition, the rubber infiltrated into the fiber material can suppress breakage, and as a result, the durability is excellent compared to a buffer material made of rubber alone. That is, such a buffer material can stably exhibit its function as a buffer material.

[0017] The present inventors obtained such an insight and completed the present invention.

[0018] A buffer material for a battery according to one aspect of the present invention is characterized in that it comprises a composite of a base material and rubber, the base material is formed of a fiber material, the rubber is infiltrated into the base material, and pores exist inside the composite.

[0019] A buffer material for a battery according to one aspect of the present invention is characterized in that the base material is paper, a woven fabric or a non-woven fabric, and the fiber material comprises one or more materials selected from glass, rock wool, carbon, ceramics, metal, polybenzoxazole, polyester, polyamide. In the case of using a woven fabric, the constituent yarns may include single yarns, ply yarns, bulked yarns, etc.

[0020] A buffer material for a battery according to one aspect of the present invention is characterized in that it comprises discrete pores dispersed in the composite.

[0021] A buffer material for a battery according to one aspect of the present invention is characterized in that the rubber comprises one or more materials selected from fluororubber, EPM (ethylene propylene copolymer), EPDM (ethylene propylene diene copolymer), hydrogenated nitrile rubber, silicone rubber, acrylate rubber, ethylene acrylate rubber and butyl rubber.

[0022] A battery according to one aspect of the present invention is characterized in that it is assembled with a buffer material for a battery formed by combining the above various features.

[0023] Effects of the Invention

[0024] According to the present invention, a buffer material for a battery that can stably exhibit its function as a buffer material and a battery obtained by using the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a cross-sectional view of the buffer material for a battery according to the present embodiment.

[0026] Figure 2 is a perspective view showing an example of a woven fabric having a three-dimensional continuous hollow structure.

[0027] Figure 3 is a diagram showing the concept of a woven fabric having a three-dimensional continuous hollow structure.

[0028] Figure 4 It is a cross-sectional view of the buffer material for a battery described in Application Example 1.

[0029] Figure 5 It is a cross-sectional view of the buffer material for a battery described in Application Example 2.

[0030] Figure 6 It is a cross-sectional view of the buffer material for a battery described in Application Example 3.

[0031] Figure 7 It is a cross-sectional view of the buffer material for a battery described in Application Example 4.

[0032] Figure 8 It is a cross-sectional view of the buffer material for a battery described in Application Example 5.

[0033] Figure 9 It is a perspective view of the buffer material for a battery described in Application Example 6.

[0034] Figure 10 It is a perspective view of the buffer material for a battery described in Application Example 7.

[0035] Figure 11 It is a perspective view of the buffer material for a battery described in Application Example 8.

[0036] Figure 12 It is a perspective view of the buffer material for a battery described in Application Example 9.

[0037] Figure 13 It is a perspective view of the buffer material for a battery described in Application Example 10.

[0038] Figure 14 It is a view schematically showing the side of a battery pack assembled with the buffer material for a battery according to the present embodiment during discharge or stabilization.

[0039] Figure 15 It is a view schematically showing the side of a battery pack assembled with the buffer material for a battery according to the present embodiment when each single cell expands during charging.

[0040] Figure 16 It is a perspective view showing a conventional buffer material for a battery module. Detailed Description of the Invention

[0041] Hereinafter, the buffer material for a battery and the battery according to the present embodiment will be described in detail. The buffer material for a battery according to the present embodiment is used as a buffer material surrounding a single cell, or is assembled between single cells of a battery pack (battery module) formed by stacking single cells (battery units), or between a case and a single cell.

[0042] (Buffer material for battery)

[0043] Figure 1 is a cross-sectional view of the buffer material for battery according to this embodiment. As Figure 1 shown, the buffer material 1 for battery according to this embodiment includes a composite body 2 of a base material 2a and a rubber 2b. The base material 2a is formed of a fibrous material, and the rubber 2b is infiltrated into the base material 2a. In addition, pores 3 exist inside the composite body 2. Therefore, compared with a buffer material made of rubber alone, the buffer material 1 for battery according to this embodiment has excellent cushioning properties and excellent durability.

[0044] As long as the base material 2a is formed of a fibrous material, its form is not limited. For example, as the form of the base material 2a, paper, woven fabric, or non-woven fabric can be cited. The form of the base material 2a can be variously selected according to the required specifications and is not limited. For example, from the viewpoint of being able to be obtained inexpensively, paper is excellent, but in order to obtain high cushioning properties, multiple sheets need to be laminated. Among them, different papers can be used in each layer to endow different properties to each layer. On the other hand, woven fabrics and non-woven fabrics as the base material are easily infiltrated with the rubber 2b, easily retain pores and air bubbles, and ensure a certain thickness, so there is an advantage that the cushioning properties are easily adjusted. In addition, in the case of woven fabrics and non-woven fabrics, there is also an advantage that it is easy to infiltrate the rubber containing a foaming agent.

[0045] In particular, woven fabrics have the advantages that their form is not easily destroyed and it is easy to form pores. The warp and weft of the woven fabric use twisted yarns obtained by twisting single fibers. In the case of a woven fabric with bulked yarns as the twisted yarns, there are the following advantages: it is easy to ensure pores when infiltrated with rubber, and it is easy to obtain higher cushioning properties.

[0046] Woven fabrics include not only plain woven fabrics such as plain weave, twill weave, and leno weave, but also woven fabrics with a three-dimensional continuous hollow structure.

[0047] Figure 2 is a perspective view showing an example of a woven fabric with a three-dimensional continuous hollow structure, Figure 3 is a diagram showing the concept of a woven fabric with a three-dimensional continuous hollow structure. As Figure 2 shown, the woven fabric 500 with a three-dimensional continuous hollow structure is a woven fabric having a hollow portion 540 formed by vertical yarns (yarns in the thickness direction) 530 between an upper woven fabric 510 and a lower woven fabric 520.

[0048] More specifically, as Figure 3As shown, the upper woven fabric 510 is formed by weaving upper warp yarns 511 and upper weft yarns 512 and 513, and the lower woven fabric 520 is formed by weaving lower warp yarns 521 and lower weft yarns 522 and 523. Further, the hollow portion 540 is a continuous cavity formed by weaving vertical yarns 530, upper warp yarns 511, and lower warp yarns 521. The woven fabric 500 with a three-dimensional continuous hollow structure can change the thickness (distance in the up-and-down direction in the drawing) and width (distance in the left-and-right direction in the drawing) of the hollow portion 540 by changing the weaving method of the vertical yarns 530, upper warp yarns 511, and lower warp yarns 521. As the woven fabric 500 with a three-dimensional continuous hollow structure, PARABEAM 3D manufactured by PARABEAM Co., Ltd. (PARABEAM is a registered trademark) can be exemplified.

[0049] As the non-woven fabric, for example, a needle-punched non-woven fabric can be exemplified. The needle-punched non-woven fabric has an advantage in that it is easy to obtain cushioning properties in the thickness direction because the fibers are mainly oriented in the thickness direction.

[0050] As the fiber material, various selections can be made according to the required specifications without limitation. As the fiber material, for example, natural fibers such as plant fibers and animal fibers; chemical fibers such as regenerated fibers, synthetic fibers, and inorganic fibers can be used. More specifically, for example, glass, rock wool, carbon, ceramics, metals, polybenzoxazole, polyester, and polyamide can be cited. As the base material 2a, one or more selected from them can be included. In particular, when glass fibers form a composite with rubber, it also has the effect of being a fiberglass reinforced rubber (FRR), and it is easy to obtain a cushioning material with more excellent heat resistance and durability.

[0051] The material of the rubber 2b can be variously selected according to the specifications (such as cushioning properties, resilience, heat resistance, and durability) required as a cushioning material without limitation. As the material of the rubber 2b, for example, fluororubber, EPM, EPDM, hydrogenated nitrile rubber, silicone rubber, acrylate rubber, ethylene acrylate rubber, and butyl rubber can be cited. As the rubber 2b, one or more selected from them can be included.

[0052] The pores 3 exist inside the composite 2. For example, there are cases where the pores 3 exist in the gaps between the fibers of the base material 2a, around the fibers, etc., in parts where the rubber 2b is not impregnated; and cases where they exist inside the rubber 2b. The pores 3 can be uniformly dispersed.

[0053] It should be noted that if vulcanization occurs after the base material 2a is impregnated with unvulcanized rubber, pores 3 are usually formed in the part not impregnated with rubber 2b. In addition, the pores 3 can be formed by using, for example, unvulcanized rubber in which a foaming agent such as thermally expandable microcapsules is dispersively kneaded. In this case, the pores 3 can be more uniformly dispersed. In particular, by kneading the foaming agent well into the unvulcanized rubber and uniformly mixing it, it is easy to apply an appropriate pressure between single cells.

[0054] (Application Example 1)

[0055] Figure 4 It is a cross-sectional view of the battery buffer material described in Application Example 1. The battery buffer material 10 described in Application Example 1 includes composites 11a, 11b, 11c, 11d, 11e, 11f of a base material and rubber. The base material is formed of paper sheets, and the rubber is impregnated into the base material. It should be noted that in the figure, although the base material and the rubber are not clearly shown, most of the parts representing the composites 11a, 11b, 11c, 11d, 11e, 11f are composed of the base material, and the rubber is impregnated in the gaps between the fibers in the base material. Specifically, the battery buffer material 10 described in Application Example 1 has a structure in which the composites 11a, 11b, 11c, 11d, 11e, 11f are laminated. Pores 12 are provided inside the composites 11a, 11b, 11c, 11d, 11e, 11f.

[0056] The fibers of the paper sheets are mainly oriented in the plane direction, and the thickness of each sheet can be reduced. Therefore, the requirements of a battery that demands space saving can be met. In addition, the pores formed by impregnating the paper sheets with rubber play a buffering role. Therefore, a battery buffer material with high buffering performance can be provided. The rubber impregnated into the fiber material can prevent the breakage of the fiber material, and the resilience of the pores is exerted by means of the rubber elasticity. Since the fibers are mainly oriented in the plane direction, uniform pressure and buffering performance can be applied in the plane. It should be noted that most of the pores are formed in the gaps between the fibers and around the fibers. The pore volume relative to the total volume of the composite is calculated as the porosity.

[0057] The battery buffer material can be adjusted / selected according to the required buffering performance, the distance between single cells, the thermal conductivity, etc., in terms of the number of paper sheets, the porosity, and the fiber material. The porosity can be adjusted according to the basis weight of the paper before impregnation, the amount, viscosity, and impregnation time of the rubber to be impregnated. In the battery buffer material 10 of the present embodiment, six substances obtained by impregnating paper sheets formed of polyamide with an unvulcanized rubber solution are overlapped and integrated by pressure vulcanization. The fiber materials of the respective paper sheets can be different materials.

[0058] The above shows an example of a multi-layer composite, which can be a single layer. The number of layers can be variously selected according to the required specifications and is not limited. In addition, paper sheets not impregnated with rubber and composites impregnated with rubber can be alternately laminated. Regarding the composition of the substrate, rubber, and pores, it is the same as the above example.

[0059] (Application Example 2)

[0060] Figure 5 It is a cross-sectional view of the battery buffer material described in Application Example 2. The battery buffer material 20 described in Application Example 2, like the battery buffer material described in Application Example 1, has composites 21a, 21b, 21c, 21d, 21e, 21f of a substrate and rubber, the substrate is formed of paper sheets, and the rubber is impregnated into the substrate. It should be noted that in the figure, although the substrate and rubber are not clearly shown, most of the parts representing the composites 21a, 21b, 21c, 21d, 21e, 21f are composed of the substrate, and the rubber is impregnated in the gaps between the fibers in the substrate. Discrete cells 22 are dispersed inside the composites 21a, 21b, 21c, 21d, 21e, 21f.

[0061] The discrete cells 22 are closed, roughly spherical pores (closed pores). The discrete cells 22 are obtained, for example, by impregnating an unvulcanized rubber in which thermally expandable microcapsules are dispersed and kneaded into the substrate and vulcanizing it. That is, when the rubber is vulcanized, the capsules expand, and thereafter, discrete cells that exist independently are formed. The discrete cells 22 become cells that are completely enclosed on the periphery and function as buffers when the composites are compressed. The porosity can be adjusted according to the amount of thermally expandable microcapsules kneaded into the rubber. Six paper sheets and five rubber sheets kneaded with thermally expandable microcapsules are alternately overlapped, and laminated and pressed at a low temperature to produce paper sheets impregnated with unvulcanized rubber. Thereafter, the entire paper sheets impregnated with unvulcanized rubber are thermally expanded and vulcanized with a heating furnace to be integrated, whereby it can be manufactured.

[0062] Different from the pores of the battery buffer material described in Application Example 1, since thermally expandable microcapsules are dispersed and kneaded into the rubber before vulcanization, pores can be more uniformly dispersed and produced. Therefore, the battery buffer material described in Application Example 2 can apply a uniform pressure to the single cell. It should be noted that in Application Example 1 and Application Example 2, polyamide is used as the fiber constituting the paper sheets, but it can contain one or more materials selected from glass, rock wool, carbon, ceramics, metal, polybenzoxazole, polyester, and polyamide.

[0063] The above shows an example of alternately laminating paper sheets and composites, but it can also be a single layer. The number of layers can be variously selected according to the required specifications and is not limited. In addition, regarding the composition of the substrate, rubber, and pores, it is the same as the above example.

[0064] (Application Example 3)

[0065] Figure 6 It is a cross-sectional view of the cushioning material for a battery described in Application Example 3. The cushioning material 30 for a battery described in Application Example 3 includes a composite of a base material and rubber. The base material is formed of a nonwoven fabric, and the rubber is impregnated into the base material. It should be noted that in the figure, although the base material and the rubber are not clearly shown, most of the part representing the composite is composed of the base material, and the rubber is impregnated in the gaps between the fibers in the base material. The interior of the composite has pores 32. The pores 32 are formed in the gaps between the fibers of the nonwoven fabric and around the fibers of the nonwoven fabric.

[0066] The fibers of the nonwoven fabric are oriented not only in the in-plane direction but also in the thickness direction, and thus have the following characteristics: they have higher cushioning properties and resilience compared to paper sheets in which the fibers are mainly oriented in the in-plane direction.

[0067] As the nonwoven fabric, needled nonwoven fabric can be used in particular. Since the fiber orientation of the needled nonwoven fabric is mainly in the thickness direction, the cushioning properties and resilience are higher. In addition, regarding the constitution of the base material, rubber, and pores, it is the same as in the above example.

[0068] (Application Example 4)

[0069] Figure 7 It is a cross-sectional view of the cushioning material for a battery described in Application Example 4. The cushioning material 40 for a battery described in Application Example 4 includes a composite of a base material and rubber. The base material is formed of a woven fabric obtained from an expanded yarn 41 using glass fibers, and the rubber is impregnated into the base material. It should be noted that in the figure, although the base material and the rubber are not clearly shown, most of the part representing the composite is composed of the base material, and the rubber is impregnated in the gaps between the fibers in the base material. In addition, the interior of the composite has pores 42. The pores 42 are formed in the gaps between the expanded yarns and around the expanded yarns.

[0070] (Application Example 5)

[0071] Figure 8 It is a cross-sectional view of the cushioning material for a battery described in Application Example 5. The cushioning material 50 for a battery described in Application Example 5 includes a composite of a base material and rubber in the same manner as the cushioning material for a battery described in Application Example 4. The base material is formed of a woven fabric obtained from an expanded yarn 51 using glass fibers, and the rubber is impregnated into the base material. It should be noted that in the figure, although the base material and the rubber are not clearly shown, most of the part representing the composite 50 is composed of the base material, and the rubber is impregnated in the gaps between the fibers in the base material. Discrete pores 52 are dispersed in the interior of the composite.

[0072] Since it is a woven fabric of the bulked yarn 51 based on glass fiber, it has heat resistance. Due to its large volume, it also has high cushioning properties. Since it is impregnated with rubber, its durability is excellent. Furthermore, since discrete pores 52 are dispersed, the cushioning properties are even higher. In the battery cushioning material 50, based on the cushioning properties and heat resistance of the bulked yarn 51 formed of glass fiber, the cushioning properties are increased by the size, number of the discrete pores 52, in other words, the ratio of the volume of the discrete pores 52 to the volume of the entire composite, and the porosity based on the pores of the discrete pores 52. The porosity can be adjusted according to the introduction amount of the thermally expandable microcapsules kneaded into the rubber. In addition, in order to apply appropriate pressure between single cells, it is preferable to uniformly mix thermally expandable microcapsules, and therefore, it is necessary to sufficiently knead the rubber.

[0073] In Application Examples 1 to 5, when heat insulation is required between single cells of a battery pack, between a battery and a housing, etc., it is preferable to use fibers with high heat resistance and rubbers with high heat insulation properties. For example, glass fibers with high heat resistance and fluororubbers or silicone rubbers with low thermal conductivity can be used. In this case, heat conduction to adjacent batteries can be suppressed, and thermal runaway of the battery can be suppressed.

[0074] (Application Example 6)

[0075] Figure 9 It is a perspective view of the battery cushioning material described in Application Example 6. The battery cushioning material 60 described in Application Example 6 includes a composite body 600 of a base material and rubber. The base material is formed of a woven fabric having a three-dimensional continuous hollow structure, and the rubber is impregnated into the base material. The composite body 600 includes an upper woven fabric 610 impregnated with rubber, a lower woven fabric 620 impregnated with rubber, and a vertical yarn 630 impregnated with rubber, and also includes a hollow portion 640. It should be noted that in the figure, although the base material and the rubber are not clearly shown, in the composite body 600, the rubber is impregnated in the gaps between the fibers of the upper woven fabric 610, the lower woven fabric 620, and the vertical yarn 630. In the battery cushioning material 60 described in Application Example 6, the hollow portion 640 functions as a pore.

[0076] The buffer material 60 for a battery described in Application Example 6 has a hollow portion 640, and thus has the following advantages: compared with a buffer material obtained from a plain weave fabric commonly used, it can obtain high cushioning performance despite being lightweight. In particular, it is useful in applications that particularly require lightweight, such as drones and unmanned aircraft. In addition, since the hollow portion 640 is a continuous cavity, it is easy for fluids such as air to flow through, and thus it also has the advantage of high heat dissipation. The buffer material 60 for a battery described in Application Example 6 can adjust cushioning performance, heat dissipation performance, etc. by adjusting the thicknesses of the upper woven fabric 610 and the lower woven fabric 620, the length of the vertical yarn 630, the impregnation amount of rubber, etc. As the fiber materials for the upper woven fabric, the lower woven fabric, and the vertical yarn, glass, rock wool, carbon, ceramics, metal, polybenzoxazole, polyester, and polyamide can be used.

[0077] (Application Examples 7 to 10)

[0078] Figure 10 It is a perspective view of the buffer material for a battery described in Application Example 7. The buffer material 61 for a battery described in Application Example 7 includes two-layer composites 600A and 600B having the same configuration as that in Application Example 6. The two-layer composites 600A and 600B are joined by an adhesive or the like. The buffer material 61 for a battery described in Application Example 7 has advantages such as being easier to obtain higher cushioning performance compared with the single-layer composite 600, and thus can be adopted according to the use of the buffer material.

[0079] It should be noted that the cushioning performance of a buffer material with a woven fabric having a three-dimensional continuous hollow structure as a base material is mainly achieved through the buckling of the vertical yarn impregnated with rubber, and the bending in the opposite directions at the joint between the vertical yarn and the upper woven fabric and at the joint between the vertical yarn impregnated with rubber and the lower woven fabric (for example, when pressure is applied to the upper and lower surfaces, the upper woven fabric moves in an arbitrary direction (for example, Figure 9 the right direction), and the lower woven fabric moves in the direction opposite to that of the upper woven fabric (for example, Figure 9 the left direction)). Therefore, when pressure is applied to the upper and lower surfaces, misalignment occurs between the upper surface and the lower surface. Therefore, when pressure is applied to the upper and lower surfaces, the two-layer composites 600A and 600B can be joined in such a way that the moving direction of the lower woven fabric of the first-layer composite 600A is the same as the moving direction of the upper woven fabric of the second-layer composite 600B.

[0080] Figure 11It is a perspective view of the buffer material for a battery described in Application Example 8. The buffer material 62 for a battery described in Application Example 8 has two-layer composites 600A and 600C in the same manner as in Application Example 7, but it is a buffer material in which the width of the hollow part of the composite layer 600C is different from the width of the hollow part of the composite 600A. The buffer material 62 for a battery described in Application Example 8 has the following advantages: compared with the buffer material 61 for a battery described in Application Example 7 using a two-layer composite of the same structure, it can change the buffering properties of the front and back. In addition, by forming two or more layers, as the buffer material for the battery as a whole, a holding force flexible with respect to the pressure caused by battery expansion can be applied. In other words, in the initial stage of expansion, it can contract with respect to a small pressure and can be held at a specified pressure until a certain specified degree of expansion. Therefore, it can be adopted according to the use of the buffer material.

[0081] Figure 12 It is a perspective view of the buffer material for a battery described in Application Example 9. The buffer material 63 for a battery described in Application Example 9 has two-layer composites 600A and 600D in the same manner as in Application Example 7, but it is a buffer material in which the thickness of the hollow part (length of the vertical yarn) of the composite layer 600D is different from the thickness of the hollow part of the composite 600A. The buffer material 63 for a battery described in Application Example 9 has the following advantages: compared with the buffer material 61 for a battery described in Application Example 7 using a two-layer composite of the same structure, it can change the buffering properties of the front and back. In addition, by forming two or more layers with different thicknesses of the hollow part (length of the vertical yarn), as the buffer material for the battery as a whole, a holding force flexible with respect to the pressure caused by battery expansion can be applied. In other words, in the initial stage of expansion, it can contract with respect to a small pressure and can be held at a specified pressure until a certain specified degree of expansion. For example, it can be configured as follows: the surface in contact with the battery is formed into a layer with high buffering properties, that is, a layer with a thick hollow part, and the layer not in contact with the battery is formed into a layer with low buffering properties, that is, a layer with a thinner hollow part than the layer on the surface in contact with the battery. In addition, it can also be the opposite. Therefore, it can be adopted according to the use of the buffer material.

[0082] Figure 13 It is a perspective view of the buffer material for a battery described in Application Example 10. The buffer material 64 for a battery described in Application Example 10 has two-layer composites 600A and 600E in the same manner as in Application Example 7, but it is a buffer material in which the orientation of the hollow part of the composite layer 600C is different from the orientation of the hollow part of the composite 600A. Compared with the buffer material 61 for a battery described in Application Example 7 using a two-layer composite of the same structure, the buffer material 64 for a battery described in Application Example 10 can change the moving direction of the upper and lower surfaces of each layer when pressure is applied to the upper and lower surfaces. Therefore, it can be adopted according to the use of the buffer material.

[0083] (Other application examples)

[0084] As a buffer material for a battery, for example, in the battery buffer material 60 described in Application Example 6, a buffer material obtained by changing a part of the composite body 600 to other composites 600C, 600D, 600E can be used. For example, it can be a buffer material obtained by cutting out a part of the composite body 600 and embedding the composites 600C, 600D, 600E into this part. In addition, a buffer material obtained by changing a part of the composite body 600 to other composites 600C, 600D, 600E can be used for a part of the multi-layer composite body. For example, in the battery buffer material 61 described in Application Example 7, it is a buffer material obtained by cutting out a part of the composite body 600B of the second layer and embedding the composites 600C, 600D, 600E into this part. Such a buffer material is useful when partial properties (such as buffering property, heat release property, etc.) are desired to be changed.

[0085] (Battery)

[0086] Figure 14 is a diagram schematically showing the side view of the battery pack assembled with the battery buffer material described in this embodiment during discharge or stabilization. Figure 15 is a diagram schematically showing the side view when each single battery expands during charging of the battery pack assembled with the battery buffer material described in this embodiment.

[0087] The battery pack 100 described in this embodiment is configured by laminating a plurality of single batteries 101a, 101b, 101c, 101d and battery buffer materials 102a, 102b, 102c, 102d, 102e in the housing. As the buffer material assembled between the batteries, the buffer materials of Application Examples 1 to 5 and forms arbitrarily combined within the scope not exceeding the gist of the present invention can be adopted.

[0088] The battery pack 100 combined with the buffer materials 102a, 102b, 102c, 102d, 102e repeatedly expands / contracts during each charge / discharge. Here, as in the prior art, the buffer material obtained using a rubber or sponge rubber sheet is likely to deform in a direction perpendicular to the compression direction ( Figure 14 the left-right direction) ( Figure 14 the up-down direction) when the single battery expands. Therefore, it is difficult to apply an appropriate pressure to the single battery. On the other hand, since the buffer material used in the battery pack 100 described in this embodiment has a base material, it is possible to suppress the composite material from deforming in a direction perpendicular to the compression direction ( Figure 14 the left-right direction) ( Figure 14 the up-down direction). Therefore, an appropriate pressure can be applied to the single battery.

[0089] In addition, the battery pack according to the present embodiment includes a cushioning material that exhibits cushioning properties such that when contracted, appropriate reaction forces are applied throughout the entire side surface of the battery to hold each single cell, and thus, the battery characteristics are excellent. It should be noted that, in the above description, the battery pack assembled with the battery cushioning material according to the present embodiment has been mainly described as an example, but the battery cushioning material according to the present embodiment can be used, for example, as a housing of a single cell or a cushioning material between a single cell and a housing.

[0090] Part or all of the above-described embodiments can be expressed by the following supplementary notes, but are not limited thereto.

[0091] (Supplementary Note 1) A battery cushioning material comprising a composite of a base material and rubber, wherein the base material is formed of a fibrous material, the rubber is impregnated into the base material, and pores exist inside the composite.

[0092] (Supplementary Note 2) The battery cushioning material according to Supplementary Note 1, wherein the base material is paper, woven fabric, or non-woven fabric.

[0093] The fibrous material includes one or more materials selected from glass, rock wool, carbon, ceramics, metal, polybenzoxazole, polyester, and polyamide.

[0094] (Supplementary Note 3) The battery cushioning material according to Supplementary Note 1 or 2, wherein the pores include discrete cells dispersed in the composite.

[0095] (Supplementary Note 4) The battery cushioning material according to any one of Supplementary Notes 1 to 3, wherein the rubber includes one or more materials selected from fluororubber, EPM, EPDM, hydrogenated nitrile rubber, silicone rubber, acrylate rubber, ethylene acrylate rubber, and butyl rubber.

[0096] (Supplementary Note 5) A battery using the battery cushioning material according to any one of Supplementary Notes 1 to 4.

[0097] (Supplementary Note 6) A method for manufacturing the battery cushioning material according to any one of Supplementary Notes 1 to 4, wherein after impregnating the base material with unvulcanized rubber,

[0098] the base material impregnated with the unvulcanized rubber is pressurized and heated to cause vulcanization.

[0099] (Supplementary Note 7) The method for manufacturing the battery cushioning material according to Supplementary Note 6, wherein the unvulcanized rubber includes thermally expandable microcapsules.

[0100] (Supplementary Note 8) The method for manufacturing the battery cushioning material according to Supplementary Note 6 or 7, wherein in a state where the base materials impregnated with the unvulcanized rubber are laminated, pressurization and heating are performed to cause vulcanization.

[0101] (Supplementary Note 9) A buffer material for a battery, which comprises a composite of a base material and rubber, the base material is formed of paper, the rubber is infiltrated into the aforementioned base material, and pores exist inside the aforementioned composite.

[0102] (Supplementary Note 10) The buffer material for a battery according to Supplementary Note 9, in which a plurality of the aforementioned composites are laminated.

[0103] (Supplementary Note 11) The buffer material for a battery according to Supplementary Note 10, in which the aforementioned composite and paper are alternately laminated.

[0104] (Supplementary Note 12) A battery, which uses the buffer material for a battery according to any one of Supplementary Notes 9 to 11.

[0105] (Supplementary Note 13) A method for manufacturing the buffer material for a battery according to any one of Supplementary Notes 9 to 12, in which, after infiltrating the uncured rubber into the aforementioned base material,

[0106] The base material infiltrated with the aforementioned uncured rubber is pressurized and heated to cause vulcanization.

[0107] (Supplementary Note 14) The method for manufacturing the buffer material for a battery according to Supplementary Note 13, in which the aforementioned uncured rubber contains thermally expandable microcapsules.

[0108] (Supplementary Note 15) The method for manufacturing the buffer material for a battery according to Supplementary Note 13 or 14, in which, in a state where the base material infiltrated with the aforementioned uncured rubber is laminated, it is pressurized and heated to cause vulcanization.

[0109] (Supplementary Note 16) A buffer material for a battery, which comprises a composite of a base material and rubber, the base material is formed of a woven fabric, the rubber is infiltrated into the aforementioned base material, and pores exist inside the aforementioned composite.

[0110] (Supplementary Note 17) The buffer material for a battery according to Supplementary Note 16, in which the woven fabric is a woven fabric obtained by using an expanded yarn of glass fiber.

[0111] (Supplementary Note 18) A battery, which uses the buffer material for a battery according to any one of Supplementary Notes 16 to 17.

[0112] (Supplementary Note 19) A method for manufacturing the buffer material for a battery according to any one of Supplementary Notes 16 to 17, in which, after infiltrating the uncured rubber into the aforementioned base material,

[0113] The base material infiltrated with the aforementioned uncured rubber is pressurized and heated to cause vulcanization.

[0114] (Supplementary Note 20) The method for manufacturing the buffer material for a battery according to Supplementary Note 19, in which the aforementioned uncured rubber contains thermally expandable microcapsules.

[0115] (Supplementary Note 21) The manufacturing method of the buffer material for a battery according to Supplementary Note 19 or 20, wherein, in a state where the base materials impregnated with the aforementioned unvulcanized rubber are laminated, pressurization and heating are performed to cause vulcanization.

[0116] (Supplementary Note 22) A buffer material for a battery, which includes a composite of a base material and rubber, the base material is formed of a nonwoven fabric, the rubber is impregnated into the aforementioned base material, and pores exist inside the aforementioned composite.

[0117] (Supplementary Note 23) The buffer material for a battery according to Supplementary Note 22, wherein the nonwoven fabric is a needle-punched nonwoven fabric.

[0118] (Supplementary Note 24) A battery that uses the buffer material for a battery according to any one of Supplementary Note 22 or 23.

[0119] (Supplementary Note 25) The manufacturing method of the buffer material for a battery according to any one of Supplementary Note 22 or 23, wherein, after impregnating the unvulcanized rubber into the aforementioned base material,

[0120] The base material impregnated with the aforementioned unvulcanized rubber is pressurized and heated to cause vulcanization.

[0121] (Supplementary Note 26) The manufacturing method of the buffer material for a battery according to Supplementary Note 25, wherein the aforementioned unvulcanized rubber contains thermally expandable microcapsules.

[0122] (Supplementary Note 27) The manufacturing method of the buffer material for a battery according to Supplementary Note 25 or 26, wherein, in a state where the base materials impregnated with the aforementioned unvulcanized rubber are laminated, pressurization and heating are performed to cause vulcanization.

[0123] (Supplementary Note 28) A buffer material for a battery, which includes a composite of a base material and rubber, the base material is formed of a woven fabric having a three-dimensional continuous hollow structure including an upper woven fabric, a lower woven fabric, and a hollow portion formed by vertical yarns (yarns in the thickness direction) between the aforementioned upper woven fabric and the aforementioned lower woven fabric, and the rubber is impregnated into the aforementioned base material.

[0124] (Supplementary Note 29) The buffer material for a battery according to Supplementary Note 28, wherein the aforementioned hollow portion is a continuous pore.

[0125] (Supplementary Note 30) A battery that uses the buffer material for a battery according to any one of Supplementary Note 28 or 29.

[0126] (Supplementary Note 31) The manufacturing method of the buffer material for a battery according to any one of Supplementary Note 28 or 29, wherein, after impregnating the unvulcanized rubber into the aforementioned base material,

[0127] The base material impregnated with the aforementioned unvulcanized rubber is pressurized and heated to cause vulcanization.

[0128] Industrial Applicability

[0129] The buffer material for a battery and the battery of the present invention can be effectively used in secondary batteries that are being promoted to have a larger capacity and a longer lifespan. The uses of secondary batteries include, for example, electrical / information / communication uses (such as mobile phones, smartphones, laptop computers, digital cameras, activity trackers, ARM computers, electronic paper, card-type electronic money, smart watches, etc.), home / small industrial uses (such as power tools, golf carts, home / care / industrial robots, etc.), large industrial uses (such as forklifts, elevators, gantry cranes, etc.), transportation system uses (such as hybrid vehicles, electric vehicles, buses, trams, ships, electric bicycles, electric motorcycles, drones, etc.), power system uses (such as various power generations, load limiters, smart grids, general household installation-type energy storage systems, etc.), medical uses (hearing aids, etc.), pharmaceutical uses (medication management systems, etc.), IoT uses, aviation / deep sea uses (such as space probes, submersible survey ships, etc.), etc.

[0130] Explanation of Reference Numerals

[0131] 1, 10, 20, 30, 40, 50 Buffer material for battery

[0132] 2 Composite body

[0133] 2a Substrate

[0134] 2b Rubber

[0135] 11a, 11b, 11c, 11d, 11e, 11f Composite body

[0136] 12, 42 Pores

[0137] 22, 32, 52 Discrete cells

[0138] 100 Battery pack (battery)

[0139] 101a, 101b, 101c, 101d Single cell

[0140] 102a, 102b, 102c, 102d, 102e Buffer material for battery

[0141] 200 Buffer material for battery module

[0142] 201 Rim

[0143] 202 Concave-convex shape

[0144] 500 Woven fabric with a three-dimensional continuous hollow structure

[0145] 510 Upper woven fabric

[0146] 520 Lower woven fabric

[0147] 530 Vertical yarn

[0148] 540 Hollow part

[0149] 511 Upper warp yarn

[0150] 512, 513 Upper weft yarns

[0151] 521 Lower warp yarn

[0152] 522, 523 Lower weft yarns

[0153] 60, 61, 62, 63, 64 Buffer materials for batteries

[0154] 600, 600A, 600B, 600C, 600D, 600E Composites

[0155] 610 Upper woven fabric impregnated with rubber

[0156] 620 Lower woven fabric impregnated with rubber

[0157] 630 Vertical yarn impregnated with rubber

[0158] 640 Hollow part

Claims

1. A buffer material for a battery, which comprises a composite of a base material and rubber, the base material is formed of a fiber material, and the rubber is infiltrated into the base material. Pores exist inside the composite.

2. The buffer material for a battery according to claim 1, wherein The base material is paper, woven fabric or non-woven fabric, The fiber material includes one or more materials selected from glass, rock wool, carbon, ceramics, metal, polybenzoxazole, polyester, polyamide.

3. The buffer material for a battery according to claim 1, wherein The pores include discrete pores dispersed in the composite.

4. The buffer material for a battery according to claim 1, wherein The rubber includes one or more materials selected from fluororubber, EPM, EPDM, hydrogenated nitrile rubber, silicone rubber, acrylate rubber, ethylene acrylate rubber and butyl rubber.

5. A battery, which uses the buffer material for a battery according to any one of claims 1 to 4.

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