Fire prevention sheet for use between battery cells and method for manufacturing the fire prevention sheet

Abstract

The present invention provides a fire-spread prevention sheet and a method for manufacturing the same, which are thin with a total thickness of 10 mm or less and equipped with an elastic sheet, and which can be fitted with a heat-seal line on the side of the fire-spread prevention sheet near the center of its thickness, thereby providing good workability when inserted between battery cells. [Solution] A fire spread prevention sheet comprises a heat-insulating elastic sheet, heat-resistant sheets provided on both main surfaces of the heat-insulating elastic sheet, and a heat-shrinkable film having perforations that tightly packages the heat-insulating elastic sheet and the heat-resistant sheet, wherein the thickness of the heat-insulating elastic sheet is 7 mm or less, the total thickness of the heat-insulating elastic sheet is 3 mm or more and 10 mm or less, and the heat seal lines formed on the heat-shrinkable film are located within a range of ±2 mm from the center in the thickness direction of the fire spread prevention sheet.

Description

Technical Field

[0001] The present invention relates to a fire spread prevention sheet and a method for manufacturing the same.

Background Art

[0002] In recent years, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell electric vehicles (FCEVs), and electric vehicles (EVs) have been rapidly penetrating the market. In vehicles adopting these electrification technologies, batteries such as lithium-ion secondary batteries having a large capacity and a high energy density play an important role. Such batteries may experience a temperature rise under conditions such as external impact or internal short circuit, and if temperature management is not appropriately performed, it may affect safety due to heat conduction to adjacent battery cells. Therefore, development of a technical method for arranging a member for controlling heat diffusion between each battery cell and effectively managing heat propagation has been underway.

[0003] For example, Patent Document 1 discloses a fire spread prevention sheet that can be interposed between heat sources such as battery cells to prevent fire spread between the heat sources. This fire spread prevention sheet has a laminate structure in which a metal film is sandwiched between a first rubber sheet and a second rubber sheet, and this metal film is a film in a state where metal particles are deposited. The fire spread prevention sheet disclosed in Patent Document 1 can suppress heat from propagating to adjacent heat sources by maintaining the flexibility of the entire sheet due to the elasticity of the rubber sheet, exerting a heat insulation effect by the metal film, and efficiently absorbing deformation due to thermal expansion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The fire-spread prevention sheet disclosed in Patent Document 1 is a type of heat-insulating elastic sheet, but in recent years, various other types of fire-spread prevention sheets have been developed. Generally, the properties required for fire-spread prevention sheets include heat insulation, elasticity which affects workability and deformation followability, as well as heat resistance and flame retardancy. Therefore, by using a fire-spread prevention sheet that combines the fire-spread prevention properties of a heat-insulating elastic sheet with another type of sheet that has different fire-spread prevention properties from the heat-insulating elastic sheet, it is possible to improve fire-spread prevention performance.

[0006] For example, combining a heat-resistant sheet with a heat-insulating elastic sheet can improve the heat resistance of the heat-insulating elastic sheet. Among these, the use of powder-supported heat-resistant sheets, which have an adhesive powder supported on their surface, is promising as a heat-resistant sheet with excellent heat resistance. However, if a powder-supported heat-resistant sheet and a heat-insulating elastic sheet are simply laminated together, the adhesive powder easily falls off the powder-supported heat-resistant sheet during transportation, construction, etc., resulting in poor workability and making it unsuitable for practical use.

[0007] The inventors first identified a problem in providing a fire-spread prevention sheet comprising a heat-insulating elastic sheet and a heat-resistant sheet with an adhesive powder supported on its surface, which can prevent the adhesive powder from falling off during transport and other operations, thereby providing good workability, as well as a method for manufacturing the same.

[0008] To solve this problem, if a powder-supported heat-resistant sheet is tightly packaged using a heat-shrinkable film that has perforations that allow for degassing for adhesion but prevent the detachment of adhesive powder, the detachment of adhesive powder can be prevented, and good workability can be obtained. Therefore, the inventors attempted to tightly package a laminate of a heat-insulating elastic sheet and a powder-supported heat-resistant sheet using a heat-shrinkable film. However, the total thickness of the entire fire-prevention sheet is a thin sheet in the order of a few millimeters, at most 10 mm, and since the central member is an elastic body, deformation during the formation of the heat seal line must also be considered. Therefore, it was technically difficult to provide the heat seal line, which is formed by heat-shrinking the heat-shrinkable film, only on the side surface of the fire-prevention sheet, let alone to adjust the position of the heat seal line to target the center of the thickness on the side surface. In fact, when the inventors diligently tried to control the position of the heat seal line, in some cases the heat seal line was shifted and provided on the main surface of the fire-prevention sheet.

[0009] The fire-resistant sheet is intended to be inserted between battery cells. Considering the ease of installation when inserting the fire-resistant sheet between battery cells, and the clearance between the battery cells and the fire-resistant sheet, the heat seal lines should be provided on the sides of the fire-resistant sheet. Furthermore, since it is necessary to consider the possibility of warping of the fire-resistant sheet due to thermal expansion, it is desirable to form the heat seal lines as close to the center of the sheet's thickness as possible. Therefore, there is a need to establish a technology for fire-resistant sheets that allows for the provision of heat seal lines at the center of the thickness on the sides of thin laminated sheets. This technology can also be applied to fire-resistant sheets using materials other than powder-supported heat-resistant sheets. [Means for solving the problem]

[0010] To solve the above problems, the inventors have conducted diligent research and have found that by introducing stages to the shrinkage of the heat-shrinkable film, it is possible to reliably provide a heat-seal line near the center of the thickness on the side surface of a fire-spread prevention sheet, even if the fire-spread prevention sheet is thin with a total thickness of 10 mm or less and has an elastic sheet. Based on the above findings, the gist of the invention disclosed herein is as follows.

[0011] (1) A heat-insulating elastic sheet and A heat-resistant sheet is provided on each of the main surfaces of the aforementioned heat-insulating elastic sheet, The aforementioned heat-insulating elastic sheet and the aforementioned heat-resistant sheet are tightly packaged with a heat-shrinkable film having perforations, A fire-spread prevention sheet equipped with, The thickness of the aforementioned heat-insulating elastic sheet is 7.0 mm or less, and the total thickness of the aforementioned heat-insulating elastic sheet is 3.0 mm or more and 10.0 mm or less. A fire-spread prevention sheet, wherein the heat-seal lines formed on the heat-shrinkable film are located within a range of ±2.0 mm from the center in the thickness direction of the fire-spread prevention sheet.

[0012] (2) The fire-spread prevention sheet according to (1) above, wherein the heat-sealing wires are provided only on three sides of the heat-insulating elastic sheet.

[0013] (3) The fire-resistant sheet is the fire-resistant sheet described in (1) or (2) above, wherein the heat-resistant sheet has an adhesive powder supported on at least its surface.

[0014] (4) The fire-spread prevention sheet according to (3) above, wherein the heat-shrinkable film has perforations with a diameter smaller than the diameter of the adhesive powder.

[0015] (5) The fire-spread prevention sheet according to (3) or (4) above, wherein the heat-resistant sheet is a porous sheet containing the adhesive powder.

[0016] (6) The fire-spread prevention sheet according to (5) above, wherein the heat-resistant sheet is an aerogel containing the adhesive powder.

[0017] (7) The heat-resistant sheet is a paper containing the adherent powder, and is the flame spread prevention sheet according to (5) above.

[0018] (8) The adherent powder is a flame retardant, and is the flame spread prevention sheet according to any one of (3) to (7) above.

[0019] (9) The heat-insulating elastic sheet contains silicone rubber, and is the flame spread prevention sheet according to any one of (1) to (8) above.

[0020] (10) An adhesive layer is provided on the main surface of the heat-insulating elastic sheet, and the heat-resistant sheet is adhered to the adhesive layer, and is the flame spread prevention sheet according to any one of (1) to (9) above.

[0021] (11) A method for manufacturing the flame spread prevention sheet according to any one of (1) to (9) above, A step of stretching a heat-insulating elastic roll sheet by a roller and pressing the stretched sheet to obtain the heat-insulating elastic sheet; A step of disposing the heat-resistant sheet on the main surface of the heat-insulating elastic sheet to obtain a laminated sheet; Folding a heat-shrinkable film before shrinkage having a perforated portion to stitch one side of the side surface of the laminated sheet, leaving an opening on the other side surface to accommodate the laminated sheet, and between an upper conveying belt and a lower conveying belt provided with a hot air generator on a side portion along the conveying direction, conveying the laminated sheet, and heat-shrinking the heat-shrinkable film located on the side surface along the conveying direction during conveying with the hot air generator; A step of finally tightly packaging the laminated sheet with the heat-shrinkable film by heat-shrinking the heat-shrinkable film located on the side surface orthogonal to the conveying direction of the laminated sheet discharged from the upper conveying belt and the lower conveying belt following the conveying; A method for manufacturing a flame spread prevention sheet including the above steps.

[0022] (12) A method for manufacturing the flame spread prevention sheet according to (10) above, The heat-insulating elastic roll sheet is stretched by a roller, an adhesive sheet is pressed against the stretched sheet and then cut, and then a heat-resistant sheet material is attached to the adhesive sheet and then pressed, thereby obtaining a laminated sheet in which the heat-insulating elastic sheet, the adhesive layer, and the heat-resistant sheet are laminated. A heat-shrinkable film before shrinkage having a perforated portion is bent to stitch one side of the side surface of the laminated sheet, and the laminated sheet is accommodated while leaving an opening on the other side surface, and the laminated sheet is conveyed between an upper conveying belt and a lower conveying belt provided with a hot air generator on a side portion along the conveying direction, and the heat-shrinkable film located on the side surface along the conveying direction during conveyance is heat-shrunk by the hot air generator. The heat-shrinkable film located on the side surface orthogonal to the conveying direction of the laminated sheet discharged from the upper conveying belt and the lower conveying belt is heat-shrunk following the conveyance, thereby finally closely packaging the laminated sheet with the heat-shrinkable film. A method for manufacturing a fire spread prevention sheet, including the above steps.

[0023] Furthermore, the present disclosure is also applicable to the inventions according to the following (13) to (24). (13) A heat-insulating elastic sheet, A heat-resistant sheet provided on at least one main surface of the heat-insulating elastic sheet and carrying an adhesive powder on at least the surface, A heat-shrinkable film for closely packaging the heat-insulating elastic sheet and the heat-resistant sheet, Comprising, The heat-shrinkable film has a perforated portion with a diameter smaller than the diameter of the adhesive powder, a fire spread prevention sheet.

[0024] (14) The fire spread prevention sheet according to (13) above, wherein the heat-resistant sheet is provided on both main surfaces of the heat-insulating elastic sheet.

[0025] (15) The fire spread prevention sheet according to (13) or (14) above, wherein a heat seal line formed on the heat-shrinkable film is provided on the side surface of the fire spread prevention sheet.

[0026] (16) The fire-spread prevention sheet according to (15), wherein the heat-sealing wire is provided on the side surface of the heat-insulating elastic sheet.

[0027] (17) The fire-spread prevention sheet according to any one of (13) to (16) above, wherein the heat-resistant sheet is a porous sheet containing the adhesive powder.

[0028] (18) The fire-spread prevention sheet according to (17) above, wherein the heat-resistant sheet is an aerogel containing the adhesive powder.

[0029] (19) The fire-spread prevention sheet according to (17) above, wherein the heat-resistant sheet is a powder-mixed paper containing the adhesive powder.

[0030] (20) The fire-spread prevention sheet according to any of (13) to (19) above, wherein the adhesive powder is a flame retardant.

[0031] (21) The fire-spread prevention sheet according to any one of (13) to (20) above, wherein the heat-insulating elastic sheet contains silicone rubber.

[0032] (22) A fire-spread prevention sheet according to any one of (13) to (21) above, wherein an adhesive layer is provided on the main surface of the heat-insulating elastic sheet, and the heat-resistant sheet is adhered to the adhesive layer.

[0033] (23) A method for manufacturing a fire-spread prevention sheet as described in any of (13) to (21) above, A process of stretching a heat-insulating elastic roll sheet with a roller, and pressing the stretched sheet to obtain the heat-insulating elastic sheet, A step of obtaining a laminated sheet by arranging the heat-resistant sheet on the main surface of the heat-insulating elastic sheet, A step of wrapping the laminated sheet with a heat-shrinkable film having perforations before shrinkage, and then tightly wrapping the laminated sheet with the heat-shrinkable film while shrinking the perforations by heat shrinkage, A method for manufacturing a fire-spread prevention sheet, including [the specified component].

[0034] (24) A method for manufacturing a fire-spread prevention sheet as described in (22) above, A process to obtain a laminated sheet in which the heat-insulating elastic roll sheet, the adhesive layer, and the heat-resistant sheet are laminated together, by stretching a heat-insulating elastic roll sheet with a roller, pressing an adhesive sheet onto the stretched sheet and then cutting it, and then attaching a heat-resistant sheet material to the adhesive sheet and then pressing it, The process involves wrapping the laminated sheet with a heat-shrinkable film having perforations before shrinkage, and then tightly wrapping the laminated sheet with the heat-shrinkable film while shrinking the perforations by heat shrinkage, A method for manufacturing a fire-spread prevention sheet, including [the specified component]. [Effects of the Invention]

[0035] According to the present invention, even a fire-spread prevention sheet that is thin with a total thickness of 10 mm or less and comprises an elastic sheet can be provided, and a method for manufacturing the same can be provided, which allows for good workability when inserting the fire-spread prevention sheet between battery cells by providing a heat-seal line near the center of the thickness on the side surface of the fire-spread prevention sheet. [Brief explanation of the drawing]

[0036] [Figure 1] This is a schematic cross-sectional view of a fire-spread prevention sheet according to one embodiment of the present invention. [Figure 2] This is a schematic perspective view of a fire-spread prevention sheet according to one embodiment of the present invention. [Figure 3] This is a schematic perspective view of a fire-prevention sheet according to one embodiment of the present invention applied to a battery cell. [Figure 4] This is a schematic cross-sectional view of a fire-spread prevention sheet according to another embodiment of the present invention. [Figure 5] This is a schematic diagram illustrating a method for manufacturing a fire-spread prevention sheet according to one embodiment of the present invention. [Figure 6] This is a schematic diagram illustrating the heat-shrinkable film before heat shrinkage used in the method for manufacturing a fire-spread prevention sheet according to the above embodiment. [Figure 7]This is a schematic diagram illustrating in detail step 4A in the method for manufacturing a fire-spread prevention sheet according to the above embodiment. [Figure 8] This is a schematic diagram illustrating in detail step 5A in the method for manufacturing a fire-spread prevention sheet according to the above embodiment. [Figure 9] This figure illustrates the position for measuring the thickness of a fire-spread prevention sheet obtained by the method for manufacturing a fire-spread prevention sheet according to the above embodiment. [Figure 10] This is a schematic diagram illustrating a method for manufacturing a fire-spread prevention sheet according to another embodiment of the present invention. [Figure 11] This is a perspective photograph of a fire-spread prevention sheet manufactured according to the above-described alternative manufacturing embodiment. [Figure 12] This is a cross-sectional photograph of a fire-spread prevention sheet manufactured according to the above-described alternative manufacturing embodiment. [Modes for carrying out the invention]

[0037] Embodiments of the present invention will be described in detail below with reference to the drawings. In principle, identical components will be given the same reference numeral, and redundant explanations will be omitted. Also, the drawings are schematic for the sake of explanation and do not accurately reflect the actual dimensions and proportions. Furthermore, in this specification, numerical ranges may be expressed by "X~Y" instead of "greater than or equal to" and "less than or equal to," in which case the numerical values ​​X and Y are included as the lower and upper limits, respectively. Moreover, in this specification, "main surface" in any sheet body configuration refers to the planar surface having the largest area of ​​the sheet body, and "side surface" refers to a surface extending in a direction perpendicular to the main surface, or a surface extending in a direction substantially perpendicular to the main surface to the extent that it can be practically considered perpendicular.

[0038] (Fire prevention sheet) One embodiment of the fire-spread prevention sheet according to this disclosure comprises a heat-insulating elastic sheet, heat-resistant sheets provided on both main surfaces of the heat-insulating elastic sheet, and a heat-shrinkable film having perforations that tightly packages the heat-insulating elastic sheet and the heat-resistant sheet, wherein the thickness of the heat-insulating elastic sheet is 7.0 mm or less, and the total thickness of the heat-insulating elastic sheet is 3.0 mm or more and 10.0 mm or less, and the heat-seal lines formed on the heat-shrinkable film are provided within a range of ±2.0 mm from the center in the thickness direction of the fire-spread prevention sheet. Another embodiment of the fire-spread prevention sheet according to this disclosure comprises at least a heat-insulating elastic sheet, a heat-resistant sheet provided on at least one main surface of the heat-insulating elastic sheet and carrying an adhesive powder on at least its surface, and a heat-shrinkable film that tightly packages the heat-insulating elastic sheet and the heat-resistant sheet, wherein the heat-shrinkable film has perforations with a diameter smaller than the diameter of the adhesive powder. A more specific description will be given with reference to the fire-spread prevention sheet 100 according to one embodiment of the present invention shown in Figure 1. A fire-spread prevention sheet 100 according to one embodiment comprises at least a heat-insulating elastic sheet 10, heat-resistant sheets 30 (31, 32) provided on both main surfaces of the heat-insulating elastic sheet, and a heat-shrinkable film 50 having perforations that tightly wraps the heat-insulating elastic sheet 10 and the heat-resistant sheets 30. In the example in Figure 1, the heat-resistant sheets 30 (31, 32) are provided on both main surfaces (both sides) of the heat-insulating elastic sheet 10. The heat-shrinkable film 50 tightly wraps the heat-insulating elastic sheet 10 and the heat-resistant sheets 30 (31, 32). Here, the thickness 10T of the heat-insulating elastic sheet 10 is 7.0 mm or less, and the total thickness 100T of the heat-insulating elastic sheet is 3.0 mm or more and 10.0 mm or less. As shown in the schematic diagrams of Figures 1 and 2, the heat-seal lines 50L formed on the heat-shrinkable film 50 are located within a range of ±2.0 mm from the center in the thickness direction of the fire-spread prevention sheet 100. In this example, the heat-shrinkable film 50 has multiple perforations 51 with a diameter smaller than the diameter of the adhesive powder supported on the heat-resistant sheet 30. In the schematic cross-sectional view of Figure 1, two perforations 51 are provided on each of the upper and lower main surfaces, but as shown in the schematic perspective view of Figure 2, a large number of perforations 51 may be provided on the main surface of the fire-prevention sheet 100 at predetermined intervals.The details of each component of the fire-spread prevention sheet, including preferred embodiments, will be described sequentially below.

[0039] <Insulating elastic sheet> The heat-insulating elastic sheet 10 is the main layer of the fire-prevention sheet 100, and by using it, the fire-prevention sheet 100 can have excellent heat insulation properties. Furthermore, when the fire-prevention sheet 100 is inserted between battery cells, the fire-prevention sheet 100 can also have shape deformation-following properties. Such a heat-insulating elastic sheet 10 can be a known sheet disclosed in, for example, Patent Document 1, or a general heat-insulating elastic sheet that can be inserted between battery cells can be used. To illustrate an example of a heat-insulating elastic sheet applicable to this embodiment, the heat-insulating elastic sheet 10 is preferably a sponge-like sheet body of a porous material, as the void portion has heat insulation properties and is elastically deformable, so it can deform to follow the thermal expansion of the battery cells.

[0040] These porous, sponge-like sheets can utilize a variety of polymer materials as elastomers, including silicone rubber primarily composed of dimethylpolysiloxane; polyurethane-based rubber materials; polyisoprene-based rubber materials; copolymers of ethylene and propylene such as EPDM; natural rubber materials; rubber composed of acrylonitrile and butadiene; and polymers of styrene and butadiene. Furthermore, polymer materials such as polyurethane derivatives, polyester polymers, polystyrene-based composites, polyolefin derivatives, and polybutadiene-based materials can also be used as thermoplastic elastomers. These materials can be used individually or combined to form composite materials.

[0041] The heat-insulating elastic sheet 10 may contain additives such as flame retardants, heat-resistant enhancers, and heat-insulating enhancers as needed. To improve heat insulation and heat resistance, the heat-insulating elastic sheet 10 may contain inorganic fillers such as silica, aluminum oxide, and magnesium hydroxide.

[0042] -Shape and size- The thickness 10T of the heat-insulating elastic sheet 10 is 7.0 mm or less. Although not intended as a limitation, for example, if the purpose is to insert a fire-preventing sheet 100 between battery cells, the heat-insulating elastic sheet 10 may be a rectangle with sides of 5 cm to 30 cm, and the thickness 10T can be 2.0 mm or more. The thickness 10T may also be 3.0 mm or more and 6.0 mm or less. The shape of the heat-insulating elastic sheet 10 is not limited to a rectangle; it may be a square, a rounded square, a circle, an ellipse, a polygon, an irregular shape, or even a composite shape combining multiple shapes. However, a rectangle is preferable from an industrial standpoint as it is easier to manufacture.

[0043] <Heat-resistant sheet> The heat-resistant sheet 30 is provided on both main surfaces of the heat-insulating elastic sheet 10. Because the fire-spread prevention sheet 100 includes the heat-resistant sheet 30, it is advantageous in that even if at least one of the heat insulation and elasticity is reduced compared to when the heat-insulating elastic sheet alone constitutes the fire-spread prevention sheet, it can still possess heat resistance and fire resistance that cannot be obtained with the heat-insulating elastic sheet 10 alone.

[0044] In Figure 1, heat-resistant sheets 30 (31, 32) are provided on both main surfaces of the heat-insulating elastic sheet 10. Providing heat-resistant sheets 30 (31, 32) on both sides of the heat-insulating elastic sheet 10 is preferable because it can suppress warping of the entire fire-spread prevention sheet 100. In this case, it is preferable that the heat-resistant sheets 31 and 32 are made of the same material and have the same shape, but they may be made of different materials and have different shapes. Furthermore, from the viewpoint of obtaining the effect of improving heat resistance by the heat-resistant sheets 30, the heat-resistant sheets 30 may be provided on only one main surface of the heat-insulating elastic sheet 10.

[0045] Preferably, the heat-resistant sheet 30 has an adhesive powder supported on at least its surface. In this case, the heat-resistant sheet 30 may contain the adhesive powder in its surface layer or interior. The base material of the heat-resistant sheet 30 may be a known porous material such as aerogel, mixed paper, or porous ceramic, or a layered material or layered-like material such as mica. It is not particularly limited as long as the desired properties are obtained, and if the base material of the heat-resistant sheet 30 is a porous material, for example, it may be a porous material on the nano-order or a porous material on the micrometer order.

[0046] <<Adhesive powder>> The adhesive powder is preferably a flame retardant that contributes to fire spread prevention. The adhesive powder may have the same fire spread prevention properties as either or both of the base material and the heat-insulating elastic sheet. On the other hand, the adhesive powder may have different fire spread prevention properties than either or both of the base material and the heat-insulating elastic sheet. For example, flame-retardant fillers and heat-insulating fillers can be used as the adhesive powder.

[0047] Examples of porous sheets, which are a type of heat-resistant sheet, include powder-supported aerogel and powder-mixed paper. Powder-supported aerogel mainly consists of silica, carbon, metal oxides, etc., with the aforementioned powder supported on at least its surface. Powder-mixed paper is made by papermaking using pulp fibers, inorganic fibers such as ceramic fibers, glass fibers, alumina fibers, and other arbitrary fibers, with the aforementioned powder supported on at least its surface.

[0048] -Shape and size- The shape and size of the heat-resistant sheet 30 are not intended to be limited, but it is preferable that they match those of the main layer, the heat-insulating elastic sheet 10. The heat-resistant sheets 30 (31, 32) can each be, for example, rectangles with sides of 5 cm to 30 cm, and their thickness should be 0.5 mm to 4.0 mm (1.0 mm to 8.0 mm for the combined thickness of two heat-resistant sheets). The thickness of the heat-resistant sheet 30 should be selected within a range that ensures the total thickness 100T of the fire-spread prevention sheet 100 is 10 mm or less. However, there is no intention to eliminate manufacturing tolerances that are normally acceptable.

[0049] <Heat shrinkable film> The heat-shrinkable film 50 tightly packages the heat-insulating elastic sheet 10 and the heat-resistant sheet 30. The fire-spread prevention sheet 100 is equipped with the heat-shrinkable film 50. Preferably, the heat-shrinkable film 50 has perforations 51 with a diameter smaller than the diameter of the adhesive powder, in which case the powder can be prevented from falling off the heat-resistant sheet 30. The diameter of the perforations 51 mentioned above is the diameter of the fire-spread prevention sheet 100 after the heat-shrinkable film 50 has been heat-shrinked, and if there are multiple perforations, the arithmetic mean is used. The arithmetic mean is also used for the diameter of the adhesive powder. If a heat-resistant sheet 30 carrying the adhesive powder is used, the diameter of the perforations 51 may be larger than the diameter of the adhesive powder before heat shrinkage, or the diameter of the perforations 51 may be smaller than the diameter of the adhesive powder even before heat shrinkage. As long as degassing is achieved with tight packaging, the relative size of the diameters before heat shrinkage does not matter. If the heat-resistant sheet 30 does not carry adhesive powder, then it is sufficient to achieve degassing associated with tight packaging. The "diameter" referred to here is the diameter of the smallest circle that encompasses each shape if one or both of the adhesive powder and / or perforations are not circular. The diameter of the perforations 51 is, for example, about 10 μm to 300 μm, and it is preferable that multiple perforations can be received by the heat-shrinkable film 50, and that they be arranged at a pitch of about 2 to 5 times the diameter of the perforations 50 (i.e., the distance between the centers of the nearest adjacent perforations 50). In order to maintain the strength of the heat-shrinkable film 50, it is also preferable to provide a row of perforations at the ends of the upper and lower main surfaces of the fire-preventing sheet 100. In this case, they should be provided at a position of 5 mm to 50 mm from the ends of the upper and lower main surfaces of the fire-preventing sheet 100.

[0050] Furthermore, in this specification, "tightly packaging the packaged object" means that, after heat shrinkage, the heat-shrinkable film 50 packaging material substantially conforms to the shape of the outermost surface of the packaged object and is in contact with it, allowing for unavoidable gaps that may exist between the surface of the packaged object and the packaging material. Additionally, when the heat-shrinkable film 50 packaging material is heat-treated to package the object, a heat seal line, which is a linear heat shrinkage distortion, is formed on the heat-shrinkable film 50, and gaps in this area are also permitted. Moreover, even if the heat-shrinkable film 50 packaging material is further deformed by external factors such as heat and pressure after packaging, it will be treated as "tightly packaging" unless a significant lifting or gap is visible to the naked eye.

[0051] Examples of polymer materials applicable to the heat-shrinkable film 50 include polyester-based materials such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyolefin-based materials such as biaxially oriented polypropylene and biaxially oriented polyethylene; styrene-based materials such as polystyrene; vinyl-based materials such as polyvinylidene chloride, polyvinyl alcohol, and ethylene-vinyl acetate copolymer; and polyamide-based materials such as biaxially oriented polyamide. These may be used individually or in combination, and various additives may be added as needed.

[0052] The thickness of the heat-shrinkable film 50 in its finished state, after heat shrinkage, from one side (i.e., the side exposed to air) to the heat-resistant sheet closest to it, is preferably 12 μm to 20 μm. The thickness of the heat-sealed wire 50L alone is preferably 200 μm or less. To minimize the reduction in the overall heat insulation performance of the fire-preventing sheet 100, the thinner the heat-shrinkable film 50, the better.

[0053] <<Heat-sealed wire>> Refer to Figure 2 in addition to Figure 1. The thickness 10T of the heat-insulating elastic sheet 10 is 7 mm or less, and the total thickness 100T of the heat-insulating elastic sheet 100 is 3 mm or more and 10 mm or less. In this embodiment, the heat seal lines 50L formed on the heat-shrinkable film 50 are provided on the side surface of the fire-prevention sheet 100, particularly on the side surface of the heat-insulating elastic sheet. Furthermore, the heat seal lines 50L formed on the heat-shrinkable film 50 are provided at a position within ±2.0 mm from the center in the thickness direction of the fire-prevention sheet 100. That is, even though the fire-prevention sheet 100 is a thin sheet, the heat seal lines 50L are provided within a range near the center position in the thickness direction of the fire-prevention sheet 100. From this viewpoint, it is preferable that the heat seal lines 50L be provided at a position within ±1.5 mm from the center in the thickness direction of the fire-prevention sheet 100, and it is particularly preferable that they be provided at a position within ±1.0 mm. Furthermore, it is preferable that the heat-seal wire 50L is formed such that the difference between the maximum and minimum values ​​of its formation position in the thickness direction of the fire-preventing sheet 100 is within 2.0 mm, and more preferably within 1.7 mm.

[0054] Furthermore, if the shape of the fire-preventing sheet 100 is rectangular or substantially rectangular, it is more preferable that the heat-sealing wires 50L are provided on three sides of the fire-preventing sheet 100, in particular on three sides of the heat-insulating elastic sheet 10, and that the heat-sealing wires 50L are provided so as not to protrude onto the side positions of the heat-resistant sheet 30 (31, 32). If the heat-sealing wires 50L are formed in this manner, when the fire-preventing sheet 100 is inserted between battery cells, interference between the battery cells and the heat-sealing wires 50L formed on the heat-shrinkable film 50 can be prevented, and the cells and the fire-preventing sheet 100 can be made more tightly fitted. In other words, if the heat-sealing wires 50L are formed in this manner, the formation of gaps between the cells and the fire-preventing sheet 100 due to the heat-sealing wires can be prevented. Furthermore, even if the fire-preventing sheet warps due to thermal expansion, the heat-sealing lines can be positioned relatively symmetrically to the heat-resistant sheet 30 (31, 32), thus providing a tear-preventing effect for the heat-shrinkable film 50.

[0055] As described above, since the surface of the heat-resistant sheet 30 (31, 32) of the fire-spread prevention sheet 100 is tightly packaged with a heat-shrinkable film 50, the shedding of adhesive powder from the heat-resistant sheet 30 can also be prevented. Therefore, even when using a powder-supported heat-resistant sheet 30, a fire-spread prevention sheet with excellent workability can be realized. As illustrated in Figure 3, the fire-spread prevention sheet 100 can be used by inserting it between battery cells, and the fire-spread prevention sheet 100 is useful because it combines heat insulation, heat resistance, and elasticity while also providing good workability.

[0056] <Adhesive layer> In the fire-spread prevention sheet 200 according to another embodiment shown in Figure 4, an adhesive layer 20 (21, 22) is provided on the main surface of the heat-insulating elastic sheet 10, and the heat-resistant sheets 30 (31, 32) are bonded to the adhesive layer 20 (21, 22), respectively. A double-sided tape type with adhesive applied to both sides of the base material can be used as the adhesive layer 20, or adhesive may be applied directly to both sides of the heat-insulating elastic sheet 10 to serve as the adhesive layer 20. Depending on the combination of the sheet materials of the heat-insulating elastic sheet 10 and the heat-resistant sheet 30, there may be reasons such as the sheets being prone to misalignment when tightly packaging the heat-insulating elastic sheet 10 and the heat-resistant sheet 30 with the heat-shrinkable film 50. In such cases, it is preferable to use the adhesive layer 20. However, if rigidity can be ensured between the heat-insulating elastic sheet 10 and the heat-resistant sheet 30, it is not necessarily required to provide the adhesive layer 20.

[0057] Examples of substrates usable for the adhesive layer 20 include synthetic resin films such as polyethylene terephthalate, polypropylene, and polyethylene. These can be used in single-layer or laminated structures, and nonwoven fabrics may also be used. Examples of adhesives usable for the adhesive layer 20 include acrylic adhesives, rubber adhesives, and silicone adhesives. The thickness of the adhesive layer 20 is not intended to be limited, but can be, for example, 50 μm to 200 μm.

[0058] The fire-spread prevention sheets 100 and 200 described above may include other sheets that contribute to the fire-spread prevention function. From the viewpoint of obtaining the effects of the present invention, it is preferable, but not limited to, that the inner outermost surface of the heat-shrinkable film 50 of the fire-spread prevention sheets 100 and 200 is a heat-resistant sheet with at least an adhesive powder supported on its surface.

[0059] Next, an embodiment of the manufacturing method for the fire-spread prevention sheet described above will be explained. Note that explanations of components that overlap with those of the fire-spread prevention sheet described above will be omitted.

[0060] (Method for manufacturing a fire-spread prevention sheet; First embodiment) First, an overall description of one embodiment of a method for manufacturing a fire-preventing sheet 100 without using the adhesive layer 20 shown in Figure 1 will be given with reference to Figure 5. The method for manufacturing the fire-preventing sheet 100 includes at least the steps of: stretching a heat-insulating elastic roll sheet 10R with rollers 1A and 1B and pressing the stretched sheet to obtain a heat-insulating elastic sheet 10 (step 1A); arranging a heat-resistant sheet 30 on the main surface of the heat-insulating elastic sheet 10 to obtain a laminated sheet (step 3A); and wrapping the laminated sheet with a heat-shrinkable film having perforations before shrinkage (step 4A), and tightly wrapping the laminated sheet with the heat-shrinkable film while shrinking the perforations by heat shrinkage (step 5A). The packaging and tight-fitting process (steps 4A and 5A) specifically includes the steps of: obtaining a laminated sheet by arranging heat-resistant sheets on both sides of the main surface of the heat-insulating elastic sheet; accommodating the laminated sheet by aligning one longitudinal side of the laminated sheet with a pre-perforated, half-folded heat-shrinkable film; applying heat to the opening side of the heat-shrinkable film to melt and cut it; then applying heat to the short side of the laminated sheet to melt and cut it to obtain a three-sided sealed body with heat-seal lines on three sides of the laminated sheet; transporting the three-sided sealed body between an upper and lower conveyor belt, with the longitudinal direction as the transport direction and a hot air generator provided on the side along the longitudinal direction, and heat-shrinking the longitudinal heat-shrinkable film with the hot air generator during transport; and finally tight-fitting the laminated sheet with the heat-shrinkable film by heat-shrinking the short-side heat-shrinkable film of the three-sided sealed body discharged from the upper and lower conveyor belts in accordance with the transport. For example, if the heat-resistant sheet 30 is made of aerogel or the like, the rigidity with respect to the heat-insulating elastic sheet 10 can be ensured, making this embodiment preferable. The following describes each step sequentially, including optional steps.

[0061] <Step 1A> First, the heat-insulating elastic roll sheet 10R, which is the pre-cut material for the heat-insulating elastic sheet 10, is stretched by rollers 1A and 1B. The stretched sheet is then pressed using a die 2 to obtain the heat-insulating elastic sheet 10. This process can be carried out using a known roll feeder and press device.

[0062] <Step 2A> A heat-resistant sheet 30 for placement on the main surface of the heat-insulating elastic sheet 10 is prepared as needed. For example, the heat-resistant base paper 30S, which is the heat-resistant sheet 30 before cutting, can be pressed using a die 2 to obtain the heat-resistant sheet 30. Alternatively, the heat-resistant sheet 30 may be obtained by pressing from a roll of paper. A known press device can be used for this step as well.

[0063] <Step 3A> Next, using a sheet lamination device or the like, the heat-resistant sheet 30 is placed on the main surface of the heat-insulating elastic sheet 10, particularly on both main surfaces, to obtain a laminated sheet.

[0064] <Steps 4A, 5A> Next, the laminated sheet obtained in the previous step is wrapped using the unshrunk heat-shrinkable film 50A having perforations 51A, and the laminated sheet is tightly wrapped with the heat-shrinkable film 50 by heat shrinking the heat-shrinkable film 50A. As this heat shrinkage occurs, the perforations 51A shrink to become perforations 51. For example, a fire-spread prevention sheet 100 can be obtained by three-sided packaging of the laminated sheet. For example, a fire-spread prevention sheet 100 can be obtained by transporting the laminated sheet created in the previous step, pulling out a roll of heat-shrinkable film 50A, folding it in half to wrap it, sealing three sides, and cutting off the excess. In this case, it is preferable to appropriately adjust the alignment so that the heat seal line 50L appears on the side of the fire-spread prevention sheet 100. Note that, as shown in Figure 6, the heat-shrinkable film 50A may have perforations 51A provided in advance. In Figure 6, perforations 51A are provided at a predetermined pitch on both ends of the heat-shrinkable film 50A. The diameter of the perforations 51A before heat shrinkage is not particularly limited as long as it satisfies the aforementioned conditions after shrinkage, and can be appropriately determined according to the shrinkage characteristics of the heat shrinkable film, for example, it can be set to about 0.5 mm to 1.5 mm. Similarly, the pitch size of the perforations 51A before heat shrinkage is not particularly limited as long as it maintains strength and can be degassed after packaging, but for example, it can be set to about 0.1 mm to 1.5 mm.

[0065] Here, with reference to Figures 7 and 8, we will further explain in detail the technical methods for positioning the heat-seal lines 50L formed on the heat-shrinkable film within a range of ±2 mm from the center in the thickness direction of the fire-spread prevention sheet 100, and for positioning the heat-seal lines 50L near the center of the thickness despite the thinness of the elastic sheet.

[0066] <<Step 4A>> Refer to Figure 7. First, a perforated portion 51A is provided, and the laminated sheet is placed in a heat-shrinkable film 50 that has been folded in half, with one longitudinal side of the laminated sheet aligned with the film, and the bag is formed. Next, heat is applied to the opening side of the heat-shrinkable film (the side opposite to the half-folded side) to melt and cut it. After that, heat is applied to the short side of the laminated sheet to melt and cut it, and the remaining side in the short direction is also melted and cut. In this way, a three-sided sealed body is obtained in which heat seal lines are provided on three sides of the laminated sheet.

[0067] <<Step 5A>> Refer to Figure 8. Next, the three-sided sealed body obtained as described above is passed through a shrink tunnel with the longitudinal direction of the laminated sheet as the conveying direction. Hot air generators 211 and 212 are provided on the sides of the lower conveying belt 201 and upper conveying belt 202 in the shrink tunnel, respectively, along the conveying direction. In Figure 8, the three-sided sealed body (laminated sheet wrapped in heat-shrinkable film) is conveyed between the lower conveying belt 201 and the upper conveying belt 202 (so-called sandwich conveying), and the heat-shrinkable film 50A located on the sides along the longitudinal direction is first heat-shrinked by the hot air generators 211 and 212 during conveying. Known hot air generators such as hair dryers can be used, and the hot air temperature can be adjusted appropriately according to the material of the heat-shrinkable film.

[0068] Then, when the three-sided sealed body (laminated sheet) is discharged from the lower conveyor belt 201 and the upper conveyor belt 202, the heat-shrinkable film 50A in the short direction of the three-sided sealed body is heat-shrinked in accordance with the conveyance. In other words, the lower hot air generator 221 and the upper hot air generator 222, which are located at the end of the conveyor belts, heat-shrink the film in stages. Through this staged heat shrinkage, the laminated sheet can be finally tightly packaged with the heat-shrinkable film 50A. Furthermore, this staged heat shrinkage of the heat-shrinkable film is necessary to position the heat seal line 50L near the center position in the thickness direction of the thin elastic sheet. Note that in Figure 8, the hot air generator 211 on the lower conveyor belt 201 is located on the front side of the page, and the hot air generator 212 on the upper conveyor belt 202 is located on the back side of the page, and they are located in point-symmetrical positions. Although point symmetry is not strictly necessary, installing the hot air generators 211 and 212 in point-symmetric positions as shown in Figure 7 is preferable in terms of controlling the formation position of the heat seal wire.

[0069] A fire-preventing sheet 100, as shown in the schematic diagram of Figure 1 above, was prepared according to the above embodiment of the manufacturing method for gradually shrinking a heat-shrinkable film. A silicone sponge manufactured by Shin-Etsu Polymer Co., Ltd. (length: 8 cm, width: 21 cm, thickness: 3.1 mm) was used as the heat-insulating elastic sheet 10. Both main surfaces of the heat-insulating elastic sheet 10 were sandwiched between heat-resistant sheets 31 and 32. Aerogel (length: 8 cm, width: 21 cm, thickness: 3.1 mm) was used as the heat-resistant sheet 30. Polyethylene manufactured by Okura Industries Co., Ltd. (model number: Wrapper V303, average thickness excluding the heat-seal line portion: 0.015 mm, average thickness of the heat-seal line portion: 0.02 mm) was used for the shrink film. Before heat shrinking, perforations 51A with a diameter of 0.7 mm were formed by making holes with insect pins in the same arrangement as shown in Figure 6, with a pitch interval of 20 mm. Heat-seal lines were provided on three sides of the heat-insulating elastic sheet 10. Furthermore, the diameter of the perforated portion 51 after heat shrinkage was visible to the naked eye, and when the diameter was measured by randomly selecting portions, it was found to be approximately 0.1 mm to 0.2 mm.

[0070] (Examples) To evaluate the formation position of the heat seal lines in detail, 20 fire-resistant sheets were manufactured under the following conditions. A silicone sponge manufactured by Shin-Etsu Polymer Co., Ltd. (length: 8 cm, width: 21 cm, thickness: 3.1 mm) was used as the heat-insulating elastic sheet 10. Both main surfaces of the heat-insulating elastic sheet 10 were sandwiched between heat-resistant sheets 31 and 32. Aerogel (length: 8 cm, width: 21 cm, thickness: 1.2 mm) was used as the heat-resistant sheets 31 and 32, and the target value of the total thickness was set to within the range of 5.6 to 5.8 mm, taking into account variations. Other conditions were the same as above. Refer to Figure 9. For convenience, below, the position 10% from the edge on the belt direction of travel will be referred to as the "upper part" (abbreviated as "top" in the table), the position 50% from the edge will be referred to as the "middle part" (abbreviated as "middle" in the table), and the position 90% from the edge will be referred to as the "lower part" (abbreviated as "bottom" in the table). For each of the obtained fire-resistant sheets, the total thickness of the fire-resistant sheet and the position of the heat seal lines were measured at the top, middle, and bottom positions using a shape measuring instrument (QUICK VISION Apex; QV-X40P1C-E, manufactured by Mitutoyo Corporation). The measurement results and evaluation results of the heat seal line positions are shown in Tables 1 and 2 below.

[0071] [Table 1]

[0072] [Table 2]

[0073] As shown in Tables 1 and 2, according to the embodiment of the above manufacturing method for gradually shrinking the heat-shrinkable film, it is possible to position the heat-seal lines formed on the heat-shrinkable film within a range of ±2 mm from the center in the thickness direction of the fire-prevention sheet, and furthermore, it is possible to position them within a range of ±1.0 mm.

[0074] (Comparative example) In the embodiment, hot air was irradiated along the conveying direction of the fire prevention sheet installed on the conveyor belt to gradually shrink the heat-shrinkable film. However, in the comparative example, unlike the embodiment, the heat-shrinkable film was shrunk without irradiating it with hot air along the conveying direction of the fire prevention sheet installed on the conveyor belt. As a result, the heat seal lines could not be properly pressed and fixed to the side surface of the fire prevention sheet, and a phenomenon was observed where the heat seal lines formed in a way that they floated up on the upper side surface of the fire prevention sheet after heat shrinkage, which clearly did not satisfy the conditions of the present invention. In the comparative example, it was difficult to accurately position the heat seal lines in the center of the thickness direction of the heat-insulating elastic sheet, which may cause problems such as poor appearance and poor adhesion of the product, and furthermore, it is feared that it may adversely affect the workability when inserting it between battery cells. Therefore, it was confirmed that the introduction of hot air irradiation along the conveying direction of the fire prevention sheet installed on the conveyor belt, as disclosed in this disclosure, is essential to achieve stable positioning of the heat seal lines near the center in the thickness direction.

[0075] (Manufacturing method; second embodiment) An embodiment of a method for manufacturing a fire-preventing sheet 200 using the adhesive layer 20 shown in Figure 4 will be described with reference to Figure 10. Details that overlap with the first embodiment of the manufacturing method described above will be omitted. The method for manufacturing a fire-preventing sheet 200 includes at least the steps of: stretching a heat-insulating elastic roll sheet 10R with rollers 4A and 4B, pressing adhesive sheets 21R and 22R onto the stretched sheet and then cutting it (step 1B); then attaching a heat-resistant sheet material to the adhesive sheet and then pressing it to obtain a laminated sheet in which the heat-insulating elastic sheet 10, adhesive layers 20 (21 and 22), and heat-resistant sheets 30 (31 and 32) are laminated (steps 2B and 3B); and wrapping the laminated sheet with a heat-shrinkable film 50A having perforations before shrinkage (step 4B); and tightly wrapping the laminated sheet with the heat-shrinkable film while shrinking the perforations by heat shrinkage (step 5B). Similar to the first embodiment of the manufacturing method, the steps of packaging and tightly sealing (steps 4B and 5B) specifically include: a step of obtaining a laminated sheet by arranging heat-resistant sheets on both sides of the main surface of the heat-insulating elastic sheet; a step of accommodating the laminated sheet by aligning one longitudinal side of the laminated sheet with a pre-perforated, half-folded heat-shrinkable film, then applying heat to the opening side of the heat-shrinkable film to melt and cut it, and then applying heat in the short direction of the laminated sheet to melt and cut it to obtain a three-sided sealed body with heat-seal lines on three sides of the laminated sheet; a step of conveying the three-sided sealed body between an upper conveyor belt and a lower conveyor belt, with the longitudinal direction as the conveying direction and a hot air generator provided on the side along the longitudinal direction, and heat-shrinking the longitudinal heat-shrinkable film with the hot air generator during conveying; and a step of finally tightly sealing the laminated sheet with the heat-shrinkable film by heat-shrinking the short direction heat-shrinkable film of the three-sided sealed body discharged from the upper and lower conveyor belts in accordance with the conveying. For example, if the heat-resistant sheet 30 is made of powder-mixed paper, it is difficult to ensure rigidity with respect to the heat-insulating elastic sheet 10, so this embodiment is preferable.

[0076] First, the heat-insulating elastic roll sheet 10R is stretched using rollers 4A, 4B, 5A, and 5B. The double-sided adhesive sheets 21R and 22R, connected to rollers 4A and 5B, are also stretched and adhered to the stretched heat-insulating elastic roll sheet 10R. The stretched sheet is then pressed using a die 6. Next, the heat-resistant sheets 30 (31 and 32) are attached to the adhesive sheets using rollers 7A and 7B, and then pressed using a die 8 to obtain a laminated sheet. Afterward, the laminated sheet is tightly packaged by heat-shrinking a heat-shrinkable film 50A, similar to the previous embodiment.

[0077] According to the embodiment of the manufacturing method described above, the fire-spread prevention sheet 200 shown in the schematic diagram of Figure 4 was prepared. A silicone sponge manufactured by Shin-Etsu Polymer Co., Ltd. (length: 10 cm, width: 17 cm, thickness: 4 mm) was used as the heat-insulating elastic sheet 10. Both main surfaces of the heat-insulating elastic sheet 10 were sandwiched between heat-resistant sheets 31 and 32. Aerogel (length: 10 cm, width: 17 cm, thickness: 1.2 mm) was used as the heat-resistant sheet 30. Polyethylene manufactured by Okura Industries Co., Ltd. (model number: Rappler V303, average thickness excluding the heat-seal line portion: 0.015 mm, average thickness of the heat-seal line portion: 0.02 mm) was used for the shrink film. Before heat shrinkage, perforations 51A with a diameter of 0.7 mm were formed by making holes with insect pins in the same arrangement as shown in Figure 6, with a pitch interval of 20 mm. Heat-seal lines were provided on three sides of the heat-insulating elastic sheet 10. Furthermore, the diameter of the perforated portion 51 after heat shrinkage was visible to the naked eye, and when the diameter was measured by randomly selecting portions, it was found to be approximately 0.1 mm to 0.2 mm. Photographs of the actual manufactured product are shown in Figures 11 and 12. As can be seen from Figure 11, the heat-seal lines are formed only on three sides of the heat-insulating elastic sheet 10.

[0078] (modified version) The above-described embodiment of the manufacturing method is merely an example, and it is possible to produce fire-spread prevention sheets 100 and 200 using known methods.

[0079] While embodiments based on this disclosure have been described above, the compounds or compositions exemplified herein are merely examples and do not limit the technical scope of the present invention to them. Other compounds or components that produce equivalent effects can be arbitrarily combined by those skilled in the art, including the modifications described herein or known technologies, and such changes or modifications are within the technical scope of the present invention. Furthermore, the present invention can be used in combination with existing known technologies, and such forms are also within the scope of the present invention. [Industrial applicability]

[0080] According to the present invention, a fire-spread prevention sheet comprising a heat-insulating elastic sheet and a heat-resistant sheet with an adhesive powder supported on its surface can be provided, which prevents the adhesive powder from falling off during transport and other operations, resulting in good workability, and is useful. [Explanation of Symbols]

[0081] 10. Thermally insulating elastic sheet 20 Adhesive layer 30 Heat-resistant sheets 50 Heat-Shrinkable Film 50L Heat-Seal Wire 100 Fire-resistant sheets

Claims

1. A heat-insulating elastic sheet, A heat-resistant sheet is provided on each of the main surfaces of the aforementioned heat-insulating elastic sheet, The aforementioned heat-insulating elastic sheet and the aforementioned heat-resistant sheet are tightly packaged with a heat-shrinkable film having perforations, A fire-spread prevention sheet equipped with, The thickness of the heat-insulating elastic sheet is 7 mm or less, and the total thickness of the fire-spread prevention sheet is 3 mm or more and 10 mm or less. The heat-seal lines formed on the heat-shrinkable film are provided within a range of ±1.0 mm from the center in the thickness direction of the fire-spread prevention sheet. The heat-resistant sheet is a fire-spread prevention sheet for use between battery cells, wherein an adhesive powder is supported on at least the surface of the heat-resistant sheet.

2. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein the heat-sealing wires are provided only on three sides of the heat-insulating elastic sheet.

3. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein the heat-shrinkable film has perforations with a diameter smaller than the diameter of the adhesive powder.

4. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein the heat-resistant sheet is a porous sheet containing the adhesive powder.

5. The fire-spread prevention sheet for use between battery cells according to claim 4, wherein the heat-resistant sheet is an aerogel containing the adhesive powder.

6. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein the heat-resistant sheet is a powder-mixed paper containing the adhesive powder.

7. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein the adhesive powder is a flame retardant.

8. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein the heat-insulating elastic sheet contains silicone rubber.

9. The fire-spread prevention sheet for use between battery cells according to claim 1, wherein an adhesive layer is provided on the main surface of the heat-insulating elastic sheet, and the heat-resistant sheet is bonded to the adhesive layer.

10. A heat-insulating elastic sheet, A heat-resistant sheet is provided on each of the main surfaces of the aforementioned heat-insulating elastic sheet, A fire-spread prevention sheet comprising a heat-shrinkable film having perforations, which tightly packages the aforementioned heat-insulating elastic sheet and the aforementioned heat-resistant sheet, The thickness of the heat-insulating elastic sheet is 7 mm or less, and the total thickness of the fire-spread prevention sheet is 3 mm or more and 10 mm or less. A method for manufacturing a fire-spread prevention sheet, wherein the heat-seal lines formed on the heat-shrinkable film are located within a range of ±1.0 mm from the center in the thickness direction of the fire-spread prevention sheet, A process of stretching a heat-insulating elastic roll sheet with a roller, and pressing the stretched sheet to obtain the heat-insulating elastic sheet, A step of obtaining a laminated sheet by arranging the heat-resistant sheet on both sides of the main surface of the heat-insulating elastic sheet, A process to obtain a three-sided seal body having heat-seal lines provided on three sides of the laminated sheet, by placing the laminated sheet along one longitudinal side of the laminated sheet in a heat-shrinkable film that has been pre-perforated and folded in half, then applying heat to the opening side of the heat-shrinkable film to melt and cut it, and then applying heat in the short direction of the laminated sheet to melt and cut it, The three-way sealing body is transported between an upper and lower conveyor belt, with the longitudinal direction as the transport direction and a hot air generator provided on the side along the longitudinal direction, and the heat-shrinkable film in the longitudinal direction is heat-shrinked by the hot air generator during transport. The process of finally tightly packaging the laminated sheet with the heat-shrinkable film by sequentially and gradually heat-shrinking the heat-shrinkable film in the short direction of the three-sided seal body discharged from the upper and lower conveyor belts in accordance with the conveyance using a lower hot air generator and an upper hot air generator provided at the end of the conveyor belt, A method for manufacturing a fire-spread prevention sheet, including

11. A heat-insulating elastic sheet, A heat-resistant sheet is provided on each of the main surfaces of the aforementioned heat-insulating elastic sheet, A fire-spread prevention sheet comprising a heat-shrinkable film having perforations, which tightly packages the aforementioned heat-insulating elastic sheet and the aforementioned heat-resistant sheet, The thickness of the heat-insulating elastic sheet is 7 mm or less, and the total thickness of the fire-spread prevention sheet is 3 mm or more and 10 mm or less. A method for manufacturing a fire-preventing sheet, wherein a heat-seal line formed on the heat-shrinkable film is provided within a range of ±1.0 mm from the center in the thickness direction of the fire-preventing sheet, an adhesive layer is provided on the main surface of the heat-insulating elastic sheet, and the heat-resistant sheet is bonded to the adhesive layer, A process to obtain a laminated sheet in which the heat-insulating elastic roll sheet, the adhesive layer, and the heat-resistant sheet are laminated together, by stretching a heat-insulating elastic roll sheet with a roller, pressing an adhesive sheet onto the stretched sheet and then cutting it, and then attaching a heat-resistant sheet material to the adhesive sheet and then pressing it, A process to obtain a three-sided seal body having heat-seal lines provided on three sides of the laminated sheet, by placing the laminated sheet along one longitudinal side of the laminated sheet in a heat-shrinkable film that has been pre-perforated and folded in half, then applying heat to the opening side of the heat-shrinkable film to melt and cut it, and then applying heat in the short direction of the laminated sheet to melt and cut it, The three-way sealing body is transported between an upper and lower conveyor belt, with the longitudinal direction as the transport direction and a hot air generator provided on the side along the longitudinal direction, and the heat-shrinkable film in the longitudinal direction is heat-shrinked by the hot air generator during transport. The process of finally tightly packaging the laminated sheet with the heat-shrinkable film by sequentially and gradually heat-shrinking the heat-shrinkable film in the short direction of the three-sided seal body discharged from the upper and lower conveyor belts in accordance with the conveyance using a lower hot air generator and an upper hot air generator provided at the end of the conveyor belt, A method for manufacturing a fire-spread prevention sheet, including

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