Cushion member, method for manufacturing same, and battery

Abstract

[Problem] To provide a cushion member with heat-insulating properties and cushioning properties having moderate resistance to external forces, as well as a battery provided with the same.　[Solution] The present invention relates to: a cushion member 1 disposed at least between a plurality of heat sources and capable of relieving the pressure that occurs when the heat sources expand, said cushion member comprising one or multiple first sheet pieces 10 of porous resin or rubber and one or multiple second sheet pieces 20 of resin or rubber, wherein the second sheet pieces 20 are of higher hardness than the first sheet pieces 10 and contain a fibrous filler 25; a method for manufacturing the same; and a battery.

Description

Cushion member, manufacturing method thereof, and battery Cross Reference

[0001] This application claims priority under the Paris Convention based on Japanese Patent Application No. 2024-043269 filed in Japan on March 19, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a cushion member, a method for manufacturing the same, and a battery.

[0003] Currently, there is a growing movement around the world to gradually replace conventional gasoline or diesel vehicles with electric vehicles in order to reduce the burden on the global environment. Electric vehicles are becoming increasingly popular, particularly in European countries such as France, the Netherlands, and Germany, as well as in China. The widespread use of electric vehicles requires high-performance batteries.

[0004] Conventionally, automotive batteries have been known in which multiple battery cells (also simply referred to as "cells") are arranged in a housing. The battery cell container expands when overheated during discharge and / or charging. When the battery cells expand, they come into contact with each other, which can lead to a chain reaction of heat transfer, resulting in abnormal overheating and even fire. To address this issue, a method is known in which cushioning members are provided between multiple battery cells (see Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2018-206604

[0006] Prior to the present invention, the inventor developed a porous resin or rubber sheet as a cushioning member. However, there is still room for improvement in this cushioning member. That is, the sheet itself needs to reduce its thickness so that, even when compressed in the thickness direction, the repulsive force from the sheet to the battery cell does not increase suddenly. To achieve this, the cushioning member needs to have thermal insulation properties and cushioning properties that prevent excessive compression due to external forces. Furthermore, developing a cushioning member that meets these requirements will also contribute to the achievement of the applicant's sustainable development goal of "ensuring access to affordable, reliable, sustainable, and modern energy for all."

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a cushion member that has heat insulating properties and cushioning properties that prevent excessive compression due to external forces, and a battery that includes the cushion member.

[0008] (1) To achieve the above object, one embodiment of a cushion member is disposed at least between a plurality of heat sources and is capable of relieving pressure when the heat sources expand, the cushion member comprising: one or more first sheet pieces of porous resin or rubber; and one or more second sheet pieces of resin or rubber, the second sheet pieces having a higher hardness than the first sheet pieces and containing a fibrous filler. (2) In another embodiment of a cushion member, preferably, the fibrous filler may primarily include fillers that are inclined with respect to the thickness direction of the cushion member. (3) In another embodiment of a cushion member, preferably, the fibrous filler may be resin fibers. (4) In another embodiment of a cushion member, preferably, the resin fibers may be polyphenylene sulfide fibers. (5) In another embodiment of a cushion member, preferably, the second sheet piece may be a porous resin or rubber sheet. (6) In another embodiment of a cushion member, preferably, the first sheet piece and / or the second sheet piece may be foamed silicone rubber sheet pieces. (7) In another embodiment of the cushion member, the first sheet pieces and the second sheet pieces may be alternately stacked. (8) In another embodiment of the cushion member, an insulating sheet may be further stacked in the thickness direction of the laminate of the first sheet pieces and the second sheet pieces. (9) To achieve the above object, a method for manufacturing a cushion member according to one embodiment of the present invention is any of the methods for manufacturing a cushion member described above, including: an extrusion step of extruding a sheet precursor containing a plurality of fibrous fillers and an uncured resin or rubber composition; a pre-cure cutting step of cutting the sheet precursor obliquely with respect to the extrusion direction in the extrusion step to produce uncured second sheet piece precursors of the second sheet pieces; a pre-cure fixing step of fixing the uncured first sheet piece precursors of the first sheet piece and the second sheet piece precursor after the pre-cure cutting step; and a post-fixing curing step of curing the fixed body after the pre-cure fixing step.(10) In another embodiment of the method for manufacturing a cushion member, preferably, the sheet precursor may contain a foaming agent in advance. (11) In one embodiment for achieving the above-mentioned object, a method for manufacturing a cushion member is any of the methods for manufacturing a cushion member described above, including: an extrusion step of extruding a sheet precursor containing a plurality of fibrous fillers and an uncured resin or rubber composition; a curing step of curing the sheet precursor; a cutting step of cutting the sheet after the curing step obliquely with respect to the extrusion direction in the extrusion step to produce the second sheet piece; and a fixing step of fixing the first sheet piece and the second sheet piece. (12) In another embodiment of the method for manufacturing a cushion member, preferably, the sheet precursor may contain a foaming agent in advance. (13) In one embodiment for achieving the above-mentioned object, a battery includes a plurality of battery cells in a housing, and includes any of the cushion members described above between the battery cells and between the battery cells and the housing, at least between the battery cells.

[0009] According to the present invention, it is possible to provide a cushion member that has heat insulating properties and cushioning properties that prevent excessive compression due to external forces, and a battery that includes the cushion member.

[0010] FIG. 1 shows a perspective view of a cushion member according to one embodiment. FIG. 2 shows a perspective view of the second sheet piece of the cushion member of FIG. 1 , and a schematic enlarged view of a portion A of the adhesive surface of the second sheet piece with the first sheet piece. FIG. 3 shows two exemplary manufacturing method flows (3A, 3B) for a cushion member according to one embodiment. FIG. 4 shows a schematic view of a portion of the manufacturing process in each flow shown in FIG. 3. FIG. 5 shows a perspective view of a first modified example of the second sheet piece of FIG. 2 , and a schematic enlarged view of a portion B of the smallest end surface of the second sheet piece according to the first modified example. FIG. 6 shows side views (6A, 6B, 6C) of three types of cushion members according to a second modified example. FIG. 7 shows a longitudinal cross-sectional view of a battery according to one embodiment, and an enlarged view of one cushion member sandwiched between battery cells in the longitudinal cross-sectional view.

[0011] 1, 1a... cushion member, 1b... heat insulating sheet, 10... first sheet piece, 20... second sheet piece, 20a... second sheet precursor, 25... fibrous filler, 30... sheet, 30a... sheet precursor, 50... battery, 51... housing, 60... battery cell (an example of a heat source).

[0012] Next, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below do not limit the invention according to the claims, and not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the present invention.

[0013] 1. Cushion member Fig. 1 shows a perspective view of a cushion member according to one embodiment. Fig. 2 shows a perspective view of a second sheet piece extracted from the cushion member of Fig. 1 and a schematic enlarged view of a portion A of the adhesive surface of the second sheet piece with the first sheet piece.

[0014] The cushion member 1 according to this embodiment is a member that is disposed at least between a plurality of heat sources and can relieve the pressure of the heat sources when they expand. Here, examples of the "heat source" include a battery cell disposed inside an automobile battery, a battery used for a device other than an automobile, or a battery cell disposed inside the battery. However, the "heat source" also includes, in addition to a battery or battery cell, a heater or a component thereof, and a component (such as a circuit board or a component on a circuit) in an electrical or electronic device.

[0015] The cushion member 1 is not particularly limited in its shape or size. The cushion member 1 may be in any shape, such as a rectangular parallelepiped, a circular cylinder, or an elliptical cylinder. A preferred shape for the cushion member 1 is a rectangular parallelepiped, particularly a sheet-like rectangular parallelepiped with one of its three sides being very small. In this case, the long side (the longest side) is preferably 100 mm or more and 800 mm or less, more preferably 200 mm or more and 500 mm or less. The short side (the second longest side), provided that it is shorter than the long side, is preferably 50 mm or more and 300 mm or less, more preferably 100 mm or more and 250 mm or less. The thickness (shortest side) is not particularly limited, but is preferably 1 mm or more and 40 mm or less, more preferably 2 mm or more and 20 mm or less.

[0016] The cushion member 1 includes one or more first sheet pieces 10 made of porous resin or rubber and one or more second sheet pieces 20 made of resin or rubber. The cushion member 1 according to this embodiment preferably has a configuration in which the first sheet pieces 10 and the second sheet pieces 20 are stacked in the width direction of the cushion member 1 (the direction of the second-longest side of the rectangular parallelepiped). However, a cushion member according to another embodiment may have a configuration in which the first sheet pieces 10 and the second sheet pieces 20 are stacked in the length direction of the cushion member 1 (the direction of the longest side of the rectangular parallelepiped). The first sheet piece 10 contains a plurality of air bubbles inside the resin or rubber, and is preferably a molded body of foamed resin or foamed rubber. Such a foam may also be referred to as a sponge body or sponge piece.

[0017] The second sheet piece 20 has a higher hardness than the first sheet piece 10 and contains a fibrous filler 25. The second sheet piece 20 does not necessarily have to be porous, but may be a porous resin or rubber sheet like the first sheet piece 10. The most significant difference between the second sheet piece 20 and the first sheet piece 10 is that the second sheet piece 20 contains a fibrous filler 25. The "hardness" refers to a hardness measured using, for example, an Asker Type A durometer conforming to JIS K 6253. Furthermore, if both the first sheet piece 10 and the second sheet piece 20 are sponge bodies, a hardness measured using an Asker Type C, Type E, or Type F durometer may also be used. If the hardness of the first sheet piece 10 and the second sheet piece 20 cannot be measured using exactly the same measurement method, for example, if it is necessary to measure the first sheet piece 10 with an Asker Type F and the second sheet piece 20 with an Asker Type C, the Type F durometer can be determined to have a lower hardness. The method for measuring hardness does not have to be limited to the method conforming to the JIS.

[0018] The matrix material (also referred to as the base material) of the first sheet piece 10 and the second sheet piece 20 is resin or rubber. There are no particular restrictions on the matrix material, but it is preferably a material with high heat resistance. When resin is used as the matrix material, suitable resins include polypropylene, polyvinylidene fluoride, polyamide, polycarbonate, polyphenylene sulfide, polyimide, polyetherimide, polytetrafluoroethylene, polyamideimide, phenolic resin, allyl resin, epoxy resin, furan resin, and silicone resin. When rubber is used as the matrix material, suitable rubbers include silicone rubber, acrylic rubber, styrene rubber, butyl rubber, ethylene propylene rubber, and fluororubber.

[0019] The matrix material of the first sheet piece 10 is a porous body having a plurality of air bubbles. The air within the air bubbles contributes to improving the thermal insulation performance of the cushion member 1. The matrix material is preferably foamed silicone rubber (also called silicone sponge). Foamed silicone rubber is a particularly preferred material because it combines the thermal insulation properties of the air within the air bubbles with the thermal insulation properties and elastic deformability of silicone rubber. The ratio of the volume of the air bubbles to the volume of the matrix material (including the air bubbles) is preferably 30 / 100 to 97 / 100, more preferably 40 / 100 to 90 / 100. The matrix material of the first sheet piece 10 does not necessarily have to be porous, but is preferably porous, and more preferably foamed silicone rubber.

[0020] The length of the fibrous filler 25 contained in the second sheet piece 20 is not limited as long as the aspect ratio (major axis / minor axis) exceeds 1. Needle-shaped fillers known as whiskers are also included in the fibrous filler 25. The fibrous filler 25 may alternatively be referred to as anisotropic filler. The length of the fibrous filler 25 is equal to or less than the thickness of the cushion member 1, preferably 10 μm to 1000 μm, more preferably 30 μm to 500 μm. The material of the fibrous filler 25 is not particularly limited, but it is preferably a material different from the matrix material constituting the second sheet piece 20, and is preferably a material with better heat resistance and / or higher hardness than the matrix material. Examples of materials for the fibrous filler 25 include ceramics, carbon materials (however, materials with high electrical insulation are preferred), and / or resins. Examples of ceramics include alumina, silicon carbide, and silicon nitride. Examples of carbon materials include natural or artificial diamond. Examples of the resin include polyphenylene sulfide and polyether ether ketone. The fibrous filler 25 is a material different from the matrix material, and is preferably a resin fiber, more preferably a polyphenylene sulfide fiber.

[0021] As shown in FIG. 2 , the fibrous filler 25 is preferably inclined with respect to the thickness direction (direction of arrow T) of the cushion member 1. The inclination angle (θ) is any acute angle, preferably 20 degrees or more and 70 degrees or less, more preferably 30 degrees or more and 60 degrees or less, and even more preferably 35 degrees or more and 50 degrees or less. Even when the inclination angle (θ) of the fibrous filler 25 is an obtuse angle, it is interpreted as being inclined at an acute angle with respect to the thickness direction of the cushion member 1. This interpretation applies hereinafter throughout this specification. It is not necessary for all of the fibrous filler 25 to be inclined at the same angle. Furthermore, some of the fibrous filler 25 may be oriented in the same direction as the thickness direction (direction of arrow T) or at 90 degrees relative to the thickness direction. The fibrous filler 25 preferably mainly includes fillers inclined with respect to the thickness direction (direction of arrow T) of the cushion member 1. Here, "mainly" means that more than 50% of the number of fibrous fillers 25. The percentage of the number of fillers in the fibrous filler 25 that are inclined with respect to the thickness direction (direction of arrow T) of the cushion member 1 is preferably 51% or more, more preferably 70% or more, and even more preferably 90% or more. Instead of "mainly", it is also possible to say that the percentage of the number is 51% or more, 70% or more, or 90% or more.

[0022] Because the cushion member 1 includes the first sheet piece 10 and the second sheet piece 20, when pressure is applied from the thickness direction of the cushion member 1, the cushion member 1 does not collapse too much and the thickness can be reduced without excessively increasing the internal pressure, compared to when the cushion member 1 is configured with the same structure as the first sheet piece 10. As described above, if the fibrous filler 25 is primarily at an inclination angle (θ) with respect to the thickness direction of the cushion member 1, when the cushion member 1 is compressed from the thickness direction, the fibrous filler 25 slightly collapses in the direction of compression or in a direction perpendicular to the compression direction. The resistance at this time is smaller than the resistance when the fibrous filler 25 is oriented along the thickness direction, but larger than the resistance when the fibrous filler 25 is oriented perpendicular to the thickness direction. As a result, it is easier to construct a cushion member 1 with appropriate resistance in the thickness direction.

[0023] 2. Method for Manufacturing Cushion Member Next, various embodiments of the method for manufacturing the cushion member will be described.

[0024] Fig. 3 shows two exemplary manufacturing method flows (3A, 3B) for a cushion member according to one embodiment. (3A) shows a manufacturing method according to a first embodiment. (3B) shows a manufacturing method according to a second embodiment. Fig. 4 schematically shows a part of the manufacturing status in each flow shown in Fig. 3. The manufacturing methods according to each embodiment will be described below with reference to Figs. 3 and 4.

[0025] (1) First Embodiment A method for manufacturing a cushion member according to this embodiment includes an extrusion step (S110), a pre-cure cutting step (S120), a pre-cure fixing step (S130), and a curing step (S140).

[0026] The extrusion process is a process of extruding a sheet precursor 30a containing a plurality of fibrous fillers 25 and an uncured resin or rubber composition. The sheet precursor 30a may contain a foaming agent in advance. Examples of extrusion methods include, but are not limited to, discharging from the outlet (opening) of a mixer or feeding through a plurality of rolls. This process involves feeding a relatively fluid composition in a completely uncured state (referred to as "uncured") in a predetermined direction (the direction of arrow F in FIG. 4 ), as long as it is possible to orient the fibrous fillers 25 in the composition in the predetermined direction. Known foaming agents can be used. Examples of foaming agents include azobisisobutyronitrile (AIBN) and azodicarbonamide (ADCA). Examples of foaming agents other than the organic foaming agents include thermally expandable resin beads.

[0027] The pre-cure cutting step is a step of cutting the sheet precursor 30a obliquely relative to the extrusion direction in the extrusion step (see dotted lines L in FIG. 4 ) to produce uncured second sheet piece precursors 20a of the second sheet pieces 20. In this step, multiple cuts are made at a fixed width, and multiple second sheet piece precursors 20a can be produced. In addition to the cuts along dotted lines L, it is preferable to make cuts along dotted lines M to produce rectangular parallelepiped second sheet piece precursors 20a.

[0028] The pre-cure fixing step is a step of fixing a first sheet piece precursor (an uncured molded body of the first sheet piece 10) prepared separately from the second sheet piece 20 to the second sheet piece precursor 20a after the pre-cure cutting step. In this embodiment, the pre-cure fixing step is a step of alternately stacking the first sheet piece precursor and the second sheet piece precursor 20a. Note that an adhesive may or may not be used for fixing.

[0029] The post-fixing curing process is a process of curing the fixed body after the pre-cure fixing process. The post-fixing curing process may be performed in one step, or in two or more steps. Foaming preferably occurs before or during complete curing. The post-fixing curing process may be divided into a primary curing process and a subsequent secondary curing process. For example, the primary curing process may be performed at a temperature of 170°C to 190°C, and the secondary curing process may be performed at a temperature of 200°C to 230°C. The primary curing process preferably mainly causes foaming and limits curing to incomplete curing. The subsequent secondary curing process preferably mainly causes complete curing of the laminate. This process completes the cushion member 1. Note that after the curing process, a post-cure cutting process may be further performed to complete the cushion member 1.

[0030] (2) Second Embodiment A method for manufacturing a cushion member according to this embodiment includes an extruding step (S210), a curing step (S220), a cutting step (S230), and a fixing step (S240).

[0031] The extrusion process is a process of extruding a sheet precursor 30a containing a plurality of fibrous fillers 25 and an uncured resin or rubber composition. The sheet precursor 30a may contain a foaming agent in advance. This process is common to the first embodiment, so a duplicated description will be omitted.

[0032] The curing step is a step of curing the sheet precursor 30a. The curing step may be performed in one step, or in two or more steps. When the sheet precursor 30a contains a foaming agent, foaming preferably occurs before or during complete curing. The curing step may be divided into a primary curing step and a subsequent secondary curing step. For example, the primary curing step may be performed at a temperature of 170°C or higher and 190°C or lower, and the secondary curing step may be performed at a temperature of 200°C or higher and 230°C or lower. In the primary curing step, foaming is preferably mainly generated, resulting in incomplete curing. In the subsequent secondary curing step, complete curing is preferably achieved.

[0033] The cutting step is a step in which the sheet 30 after the curing step is cut obliquely relative to the extrusion direction in the extrusion step (see dotted lines L in FIG. 4 ) to produce second sheet pieces 20. In this step, multiple cuts are made at a fixed width, so that multiple second sheet pieces 20 can be produced. It is preferable to make cuts along dotted lines M in addition to the cuts along dotted lines L to produce rectangular second sheet pieces 20.

[0034] The fixing process is a process of fixing the first sheet piece 10, which is prepared separately from the second sheet piece 20, to the second sheet piece 20 after the cutting process. In this embodiment, the fixing process is a process of alternately stacking the first sheet piece precursor and the second sheet piece precursor 20a. An adhesive can preferably be used for fixing. With this process, the cushion member 1 is completed. Note that after the fixing process, a cutting process may be further performed to complete the cushion member 1.

[0035] 5 shows a perspective view of a first modified example of the second sheet piece of FIG. 2 and a schematic enlarged view of a portion B of the smallest end face of the second sheet piece of the first modified example.

[0036] In the second sheet piece 20 constituting the cushion member 1 according to the first modification, the fibrous filler 25 at its smallest end surface is inclined with respect to the thickness direction (direction of arrow T) of the cushion member 1. The inclination angle (θ) is any acute angle, preferably 20 degrees or more and 70 degrees or less, more preferably 30 degrees or more and 60 degrees or less, and even more preferably 35 degrees or more and 50 degrees or less. It is not necessary for all of the fibrous filler 25 to be inclined at the same angle. Furthermore, some of the fibrous filler 25 may be oriented in the same direction as the thickness direction (direction of arrow T) or at a 90-degree angle relative to the thickness direction. However, the fibrous filler 25 preferably mainly includes fillers inclined with respect to the thickness direction (direction of arrow T) of the cushion member 1. The term "mainly" overlaps with the description given with reference to FIG. 2 and is therefore omitted here.

[0037] The fibrous filler 25 may be inclined on either the widest surface or the smallest end surface of the second sheet piece 20, but is usually inclined on both surfaces (including the cross section).

[0038] 4. Second Modification of Cushion Member and Manufacturing Method Thereof Figure 6 shows side views (6A, 6B, 6C) of three types of cushion members according to the second modification.

[0039] The cushion member 1a includes the cushion member 1 described above and a heat insulating sheet 1b different from the cushion member 1. The heat insulating sheet 1b is preferably a sheet having excellent heat insulating properties. The heat insulating sheet 1b is preferably also excellent in flame retardancy. The heat insulating sheet 1b is more preferably a sheet having higher heat insulating properties than the first sheet piece 10, the second sheet piece 20, or their laminate. The cushion member 1a preferably includes a heat insulating sheet 1b further laminated in the thickness direction of the laminate of the first sheet piece 10 and the second sheet piece 20 (the cushion member 1 in this embodiment).

[0040] As shown in Figure 6, exemplary forms of the cushion member 1a include a form in which one cushion member 1 and one heat insulating sheet 1b are attached (6A), a form in which one heat insulating sheet 1b is sandwiched between two cushion members 1 (6B), or a form in which one heat insulating sheet 1b is sandwiched between two cushion members 1 and the ends of the two cushion members 1 are attached to form a bag (6C).

[0041] The heat insulating sheet 1b is preferably a sheet containing talc as its main component, but is not limited thereto. It is sufficient if it is made of a material that has at least higher heat insulating properties and higher flame retardancy than the cushion member 1. Examples of such materials include silica, aerogel (particularly preferably silica aerogel), mullite, cordierite, steatite, forsterite, titania, and zirconia. The heat insulating sheet 1b may or may not have excellent electrical conductivity. However, it is preferable that the heat insulating sheet 1b exhibit high insulating properties. The heat insulating sheet 1b is preferably a sheet with excellent flexibility (or flexibility). There are no restrictions on its thickness, but a thickness of 0.02 to 3 mm is preferred, and 0.1 to 0.5 mm is more preferred. The thickness of the heat insulating sheet 1b is preferably smaller than that of the cushion member 1. However, the thickness of the heat insulating sheet 1b is preferably determined by comprehensively considering strength, flexibility, and heat insulating properties.

[0042] Here, "as the main component" or "main material" means a proportion of more than 50% by mass of the total mass. The talc used as the main component of the heat insulating sheet 1b is generally a ceramic whose main component is hydrated magnesium silicate, and contains small amounts of impurities such as iron oxide. The type and amount of impurities vary depending on the source of the talc ore, but the talc contained in the heat insulating sheet 1b is not particularly limited in these respects.

[0043] The average particle size of the main material (which may also be referred to as an inorganic material, ceramic, or metal oxide) of the heat insulating sheet 1b, such as talc, silica, aerogel (particularly preferably silica aerogel), mullite, cordierite, steatite, forsterite, titania, or zirconia, as measured by laser diffraction is preferably 0.1 μm to 50 μm, more preferably 1 μm to 30 μm. Furthermore, talc may be surface-treated with a known surface treatment agent, such as an organosilane compound, an organoborane compound, an epoxy compound, an organotitanate compound, or an isocyanate compound. The heat insulating sheet 1b may contain only one of the above-mentioned main materials, or may contain two or more types with different average particle sizes, types, surface treatment agents, etc.

[0044] In the manufacturing process of the cushion member 1a, after the cushion member 1 is completed, an integration step is carried out in which the cushion member 1 and the heat insulating sheet 1b are attached to each other or the heat insulating sheet 1b is sandwiched between two cushion members 1. When joining the cushion member 1 and the heat insulating sheet 1b in the integration step, an adhesive may be used.

[0045] 5. Battery Figure 7 shows a longitudinal cross-sectional view of a battery according to one embodiment and an enlarged view of one cushion member sandwiched between battery cells in the longitudinal cross-sectional view.

[0046] The battery 50 according to this embodiment is, for example, a battery for an electric vehicle, and includes a plurality of battery cells (also simply referred to as "cells") 60 arranged side by side. In this embodiment, the number of battery cells 60 is eight, but may be two to seven, or nine or more. The battery 50 is a storage battery, preferably a lithium-ion battery. The battery 50 includes a housing 51 with a bottom that is open on one side. The battery cells 60 are disposed inside an interior 52 of the housing 51. The plurality of battery cells 60 are preferably pressed against each other by applying compressive force from both sides of the housing 51 using screws or the like (not shown). The bottom of the housing 51 is provided with a through-hole 53 for flowing cooling water, which is an example of a coolant. The coolant may also be referred to as a cooling medium or a coolant. The battery cells 60 are disposed inside the housing 51 with cushion members 1 sandwiched between adjacent battery cells 60.

[0047] As described above, the battery 50 according to this embodiment includes a plurality of battery cells 60 in the housing 51, and includes cushion members 1 at least between the battery cells 60, either between the battery cells 60 or between the battery cells 60 and the housing 51. The cushion members 1 do not have to be disposed between the battery cells 60 and the housing 51.

[0048] The cushion member 1 is sandwiched and compressed between the battery cells 60 when the battery cells 60 are set in the housing 51, and even if the situation of subsequent release of compression is repeated many times, the cushion member 1 elastically deforms in its thickness direction and easily recovers to its original thickness. Furthermore, the cushion member 1 is compressed in its thickness direction when it is stored in the housing 51 in a compressed state between the battery cells 60, and is further compressed when the battery cells 60 heat and expand during charging and / or discharging of the battery 50. The cushion member 1 can reduce the risk of excessive collapse of air bubbles even when compressed by the battery cells 60. As a result, the insulating properties of the cushion member 1 can be maintained at a high level. Additionally, the cushion member 1 has the function of reducing heat transfer from an overheated battery cell 60 to an adjacent battery cell 60 when the battery cell 60 overheats. Note that a cushion member 1a may be used instead of the cushion member 1.

[0049] 6. Other Embodiments Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be practiced in various modified forms.

[0050] The cushion member 1 described above has a configuration in which first sheet pieces 10 and second sheet pieces 20 are alternately stacked, but is not limited to such a configuration in which long members are stacked in one direction. For example, the first sheet pieces 10 and second sheet pieces 20 may both be formed into a rod shape to produce a sheet in which the cushion member 1 is arranged in a grid pattern in a plan view. Alternatively, the first sheet pieces 10 and second sheet pieces 20 may be formed into an L-shaped block shape in a plan view, and the pieces 10, 20 may be alternately arranged in order inside the L shape, and finally a rectangular parallelepiped first sheet piece 10 (or second sheet piece 20) may be arranged to complete the sheet-shaped cushion member 1.

[0051] The fibrous filler 25 does not necessarily have to include filler that is inclined with respect to the thickness direction of the cushion member 1, 1 a. As long as the second sheet piece 20 has a higher hardness than the first sheet piece 10 and contains the fibrous filler 25, the dispersion state of the fibrous filler 25 is not important.

[0052] The features of the claims may be combined in any combination except where they are incombinable with one another.

[0053] The present invention can be used as a sheet that can be compressed and deformed in response to the expansion of a heat source.

Claims

1. A cushion member that is placed at least between multiple heat sources and can relieve pressure when the heat sources expand, comprising one or more first sheet pieces of porous resin or rubber, and one or more second sheet pieces of resin or rubber, wherein the second sheet pieces have a higher hardness than the first sheet pieces and contain a fibrous filler.

2. The cushion member according to claim 1, wherein the fibrous filler mainly includes fillers that are inclined with respect to the thickness direction of the cushion member.

3. The cushion member according to claim 1 or 2, wherein the fibrous filler is a resin fiber.

4. The cushion member according to claim 3, wherein the resin fibers are polyphenylene sulfide fibers.

5. A cushion member according to any one of claims 1 to 4, wherein the second sheet piece is a porous resin or rubber sheet.

6. A cushion member according to any one of claims 1 to 5, wherein the first sheet piece and / or the second sheet piece is a sheet piece of foamed silicone rubber.

7. A cushion member according to any one of claims 1 to 6, characterized in that the first sheet pieces and the second sheet pieces are alternately stacked.

8. A cushion member described in any one of claims 1 to 7, characterized in that an insulating sheet having higher insulating properties than the first sheet piece and the second sheet piece is further laminated in the thickness direction of the laminate of the first sheet piece and the second sheet piece.

9. A method for manufacturing a cushion member according to any one of claims 1 to 8, comprising: an extrusion process for extruding a sheet precursor containing a plurality of fibrous fillers and an uncured resin or rubber composition; a pre-cure cutting process for cutting the sheet precursor obliquely relative to the extrusion direction in the extrusion process to produce an uncured second sheet piece precursor of the second sheet piece; a pre-cure fixing process for fixing the uncured first sheet piece precursor of the first sheet piece and the second sheet piece precursor after the pre-cure cutting process; and a post-fixing curing process for curing the fixed body after the pre-cure fixing process.

10. The method for manufacturing a cushion member according to claim 9, wherein the sheet precursor already contains a foaming agent.

11. A method for manufacturing a cushion member according to any one of claims 1 to 8, comprising: an extrusion step of extruding a sheet precursor containing a plurality of fibrous fillers and an uncured resin or rubber composition; a curing step of curing the sheet precursor; a cutting step of cutting the sheet after the curing step obliquely with respect to the extrusion direction in the extrusion step to produce the second sheet piece; and a fixing step of fixing the first sheet piece and the second sheet piece together.

12. The method for manufacturing a cushion member according to claim 11, wherein the sheet precursor already contains a foaming agent.

13. A battery having a plurality of battery cells in a housing, characterized in that the cushion member according to any one of claims 1 to 8 is provided at least between the battery cells, either between the battery cells or between the battery cells and the housing.

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