Fire spread prevention sheet, method for manufacturing same, and battery provided with same

Abstract

To provide a fire spread preventing sheet capable of being flexibly and elastically deformed corresponding to the fluctuations of pressure applied in the thickness direction of the sheet and excellent in heat insulating properties.SOLUTION: The present invention relates to a fire spread prevention sheet 1 that is disposed at least between a plurality of heat sources and is capable of preventing fire spread by suppressing heat transfer to other heat sources when a heat source is in an overheated state, the fire spread prevention sheet 1 being formed by alternately laminating a long first rubber member 10 and a long second rubber member 20 having a lower rubber hardness than the first rubber member in a width direction of each other in one direction in a plane of the sheet, the second rubber member 20 is constituted so that the thickness of a part or the whole of it is smaller than the thickness of the first rubber member 10, and the second rubber member 20 has a groove 21 extending along the longitudinal direction at an arbitrary position in the width direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fire prevention sheet, a method for manufacturing the same, and a battery including the same. [Background technology]

[0002] 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.

[0003] Some batteries may experience thermal runaway during discharge or charging, resulting in fire, smoke, or other problems. Recently, automotive batteries with multiple battery cells arranged in a housing have become known. In such a battery with multiple battery cells arranged in a row, if one battery cell were to catch fire or emit smoke, the heat could be transferred to the surrounding battery cells, potentially causing further fires, smoke, explosions, or other problems. To minimize damage caused by such problems, methods have been developed to prevent the transfer of heat from abnormally hot battery cells to the surrounding battery cells. For example, a known method involves providing a fire-prevention sheet, such as a fire-resistant material or a heat-insulating layer, between multiple battery cells (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-206604 Summary of the Invention [Problem to be solved by the invention]

[0005] The containers of the battery cells (also simply referred to as "cells") that make up a battery may expand due to increased internal pressure during discharge and / or charge. This fire-prevention sheet is required to be able to flexibly change its thickness in accordance with the expansion and subsequent contraction of the battery cells, and to have the ability to inhibit heat transfer between the battery cells (thermal insulation performance). However, conventionally known fire-prevention sheets are insufficient in terms of flexible elastic deformation and thermal insulation, and there is a demand in the market for a fire-prevention sheet that exhibits such performance. Meeting this demand 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."

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a fire prevention sheet that can flexibly and elastically deform in response to fluctuations in pressure applied in the thickness direction of the sheet and has excellent insulating properties, and a battery equipped with the same. [Means for solving the problem]

[0007] (1) A fire spread prevention sheet according to one embodiment for achieving the above object comprises: A fire prevention sheet that is disposed at least between a plurality of heat sources and that can prevent the spread of fire by suppressing heat transfer to other heat sources when the heat sources are in an overheated state, The sheet is formed by laminating elongated first rubber members and elongated second rubber members having a rubber hardness lower than that of the first rubber members alternately in the width direction in one direction within the plane of the sheet, The second rubber member is configured so that a part or all of its thickness is smaller than a thickness of the first rubber member, The second rubber member has a groove extending along the longitudinal direction at an arbitrary position in the width direction thereof. (2) In another embodiment of the fire spread prevention sheet, the first rubber member may preferably have a thickness at any position in its width direction that is greater than the thickness of any part of the second rubber member. (3) In another embodiment of the fire spread prevention sheet, the first rubber member and the second rubber member may be laminated together with their inclined surfaces inclined with respect to the thickness direction of the fire spread prevention sheet. (4) In another embodiment of the fire spread prevention sheet, the fire spread prevention sheet may preferably have a piece portion with a thickness smaller than the thickness of the fire spread prevention sheet on two opposing sheet end surfaces. (5) In the fire spread prevention sheet according to another embodiment, the two opposing sheet end faces may preferably be end faces on both ends of the groove. (6) A method for manufacturing a fire spread prevention sheet according to one embodiment for achieving the above object includes: A method for producing any one of the fire spread prevention sheets described above, The method includes a first lamination step of alternately laminating a first rubber that is the base of the first rubber member and a second rubber that is the base of the second rubber member. (7) A method for manufacturing a fire spread prevention sheet according to one embodiment for achieving the above object includes: A method for producing any one of the fire spread prevention sheets described above, a second lamination step of alternately laminating a first uncured rubber, which is the first rubber that is the base of the first rubber member and an uncured second uncured rubber, which is the base of the second rubber member; and a curing step of curing the uncured laminated body after the second lamination step. (8) In another embodiment of the method for manufacturing a fire spread prevention sheet, it is preferable that the method further includes a slicing step of slicing the laminate obtained by the first lamination step to a predetermined width in the lamination direction or at an acute angle to the lamination direction. (9) In another embodiment of the method for manufacturing a fire spread prevention sheet, it is preferable that the method further includes a slicing step of slicing the laminate obtained by the curing step to a predetermined width in the stacking direction or at an acute angle to the stacking direction. (10) In order to achieve the above object, a battery according to one embodiment is a battery including a plurality of battery cells in a housing, Any one of the fire spread prevention sheets described above is provided at least between the battery cells, among between the battery cells and between the battery cells and the housing. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a fire spread prevention sheet that can flexibly and elastically deform in response to fluctuations in pressure applied in the thickness direction of the sheet and has excellent heat insulating properties, and a battery equipped with the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows a perspective view of a fire spread prevention sheet according to a first embodiment and an enlarged view of a part A of a side surface thereof. [Figure 2] FIG. 2 shows a perspective view of a fire spread prevention sheet according to a second embodiment and an enlarged view of a part A of a side surface thereof. [Figure 3] FIG. 3 shows a perspective view of a fire spread prevention sheet according to a third embodiment and an enlarged view of a part A of the side surface thereof. [Figure 4] FIG. 4 shows a perspective view of a fire spread prevention sheet according to a fourth embodiment. [Figure 5] FIG. 5 shows a perspective view of a fire spread prevention sheet according to a fifth embodiment. [Figure 6] FIG. 6 shows the results of stress simulations for the first embodiment (6A) and an example of the second embodiment (6B). [Figure 7] FIG. 7 shows the results of stress simulations for an example of the second embodiment (7A) and a third embodiment (7B). [Figure 8] FIG. 8 shows the results of a stress simulation according to the conventional example. [Figure 9] FIG. 9 is a schematic diagram showing an example of a method for producing a fire spread prevention sheet. [Figure 10] FIG. 10 shows a vertical cross-sectional view (10A) of the battery according to the first embodiment and a schematic plan view (10B) of the fire spread prevention sheets sandwiched between the battery cells and between the battery cells and the housing. [Figure 11] FIG. 11 shows a vertical cross-sectional view of the battery according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, various embodiments of the present invention will be described with reference to the drawings. Note that the various embodiments described below do not limit the scope of the invention as claimed, and not all of the elements and combinations thereof described in the various embodiments are necessarily essential to the solution of the present invention.

[0011] 1. Fire prevention sheet First Embodiment FIG. 1 shows a perspective view of a fire spread prevention sheet according to a first embodiment and an enlarged view of a portion A of its side surface. The fire spread prevention sheet 1 according to this embodiment is a sheet that is placed at least between multiple heat sources and can prevent the spread of fire by suppressing heat transfer to other heat sources when a heat source is overheated. Here, examples of "heat sources" include battery cells placed inside an automobile battery, batteries used in devices other than automobiles, or battery cells placed inside such batteries. However, "heat sources" also include, in addition to batteries or battery cells, for example, heaters or their components, and components in electrical or electronic devices (circuit boards, circuit components, etc.).

[0012] The fire spread prevention sheet 1 is formed by alternately laminating long first rubber members 10 and long second rubber members 20, each having a lower rubber hardness than the first rubber members 10, in one direction within the plane of the sheet. In this embodiment, the interface 30 between the first and second rubber members 10, 20 is perpendicular to the width direction of the sheet. In other words, the interface 30 is not inclined. The second rubber member 20 is configured so that a portion or all of its thickness is smaller than the thickness of the first rubber member 10. Furthermore, the second rubber member 20 has a groove 21 extending along the longitudinal direction at any position in the width direction. In this application, the thickness of the fire spread prevention sheet in each embodiment is determined based on the thickness T2 of the end face of the first rubber member 10 in the width direction.

[0013] As shown in Fig. 1, at least the second rubber member 20 has at least one groove 21 that is recessed more than other portions of the member 20. The groove 21 may be formed by gradually reducing the thickness of the second rubber member 20 from the interface 30 toward the center in the width direction as shown in Fig. 1 etc., or the thickness of the entire second rubber member 20 may be smaller than the end faces in the width direction of the first rubber member 10. In this embodiment, the fire spread prevention sheet 1 has the groove 21 in the long side direction of the sheet 1.

[0014] The thickness of the second rubber member 20 is based on the thickness T1 of the smallest point (for example, the straight line connecting the most recessed points in the member 20). When thickness T1 is smaller than thickness T2, the second rubber member 20 can have at least a portion of its thickness smaller than the thickness of the first rubber member 10. By configuring the second rubber member 20 in this way, when the fire spread prevention sheet 1 is sandwiched between battery cells 200, as will be described later, the grooves 21 can form gaps 150. The gaps 150 form an air layer between the battery cells 200 and the fire spread prevention sheet 1, thereby further improving thermal insulation.

[0015] The first rubber member 10 preferably has a thickness at any position in its width direction that is greater than the thickness of any part of the second rubber member 20. That is, as shown in FIG. 1, the first rubber member 10 preferably has at least one protruding portion 11 that protrudes more than other parts of the member 10. The thickness of the first rubber member 10 is measured based on the thickness T3 of the largest part (for example, a straight line connecting the most protruding parts of the member 20). Thickness T3 is greater than thickness T1 and equal to or greater than thickness T2, and is preferably greater than thickness T2.

[0016] The thickness T2 is not particularly limited, but is preferably 1 to 20 mm, and more preferably 2 to 8 mm. The thicknesses T3 and T1 can be set within the following ranges, for example: The thickness T3 can be set within the range of 1 to 20 mm, and the thickness T1 can be set within the range of 0.5 to 15 mm. Alternatively, the thickness T3 can be set within the range of 1 to 6 mm, and the thickness T1 can be set within the range of 0.5 to 5 mm.

[0017] When the value of thickness T2 is taken as 100%, the values ​​of thickness T3 and thickness T1 preferably vary within a range of ±1 to 5% of the value of thickness T2, more preferably within a range of ±1.5 to 4%, and even more preferably within a range of ±2 to 3%. That is, the value of thickness T1 is preferably 95 to 99%, more preferably 96 to 98.5%, and even more preferably 97 to 98% of the value of thickness T2. Furthermore, the value of thickness T3 is preferably 101 to 105%, more preferably 101.5 to 104%, and even more preferably 102 to 103% of the value of thickness T2.

[0018] The rubber constituting the first rubber member 10 and the second rubber member 20 preferably includes a thermosetting elastomer such as silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, nitrile rubber (NBR), or styrene butadiene rubber (SBR); a thermoplastic elastomer such as a urethane-based, ester-based, styrene-based, olefin-based, butadiene-based, or fluorine-based elastomer, or a composite thereof. Among rubbers, silicone rubber, which has relatively high heat resistance, is more preferably used. Therefore, the first rubber member 10 and the second rubber member 20 are preferably both silicone rubber sheets.

[0019] The first rubber member 10 and the second rubber member 20 also differ in hardness. The hardness of the first rubber member 10 is higher than that of the second rubber member 20. The hardness of the first rubber member 10 and the second rubber member 20 refers to the hardness based on JIS K 6253 and JIS K 7312. The width of the first rubber member 10 and the second rubber member 20 is not particularly limited, but is preferably 2 to 50 mm, more preferably 5 to 20 mm. The length of the first rubber member 10 and the second rubber member 20 is also not particularly limited, but is longer than the width, preferably 200 to 700 mm, more preferably 300 to 600 mm. The sizes of the first rubber member 10 and the second rubber member 20 in a plan view may be the same or different. The first rubber member 10 and the second rubber member 20 may be foamed sheets or non-foamed sheets.

[0020] Second Embodiment FIG. 2 shows a perspective view of a fire spread prevention sheet according to a second embodiment and an enlarged view of a part A of its side surface. In the fire spread prevention sheet 1a according to this embodiment, the interface 30 between the first rubber member 10 and the second rubber member 20 is inclined. In other words, the fire spread prevention sheet 1a is laminated with inclined surfaces that are inclined in the thickness direction of the sheet. Other structures and materials of the fire spread prevention sheet 1a are the same as those of the fire spread prevention sheet 1. Below, the differences between the fire spread prevention sheet 1a and the fire spread prevention sheet 1 will be further explained.

[0021] The angle θ between the surface of the first rubber member 10 or the second rubber member 20 on the side located in the width direction of the sheet 1a and the interface 30 is not particularly limited, but is preferably greater than 0 degrees and less than 90 degrees, more preferably 30 to 75 degrees, and even more preferably 45 to 60 degrees.

[0022] Third Embodiment 3 shows a perspective view of a fire spread prevention sheet according to a third embodiment. In this embodiment, the fire spread prevention sheet 1b has the grooves in the direction of the short side of the sheet 1b. The other structures and materials of the fire spread prevention sheet 1b are the same as those of the fire spread prevention sheet 1.

[0023] <Fourth embodiment> FIG. 4 shows a perspective view of a fire spread prevention sheet according to a fourth embodiment. The fire spread prevention sheet 1c according to this embodiment has strips 40 with a thickness T0, which is smaller than the thickness T2, on two opposing sheet end surfaces. The two opposing sheet end surfaces are preferably the end surfaces on both ends of the groove. By providing the strips 40, air can easily pass from the air layer formed by the grooves 21 of the second rubber member 20 into the gap between the strips 40 and the battery cell 200, thereby further improving the heat insulating performance. The other structure and materials of the fire spread prevention sheet 1c are the same as those of the fire spread prevention sheet 1. Below, we will further explain the differences between the fire spread prevention sheet 1c and the fire spread prevention sheet 1.

[0024] The material of the piece 40 is not particularly limited as long as it has excellent heat resistance, and may be the same as the first rubber member 10 or the second rubber member 20, or may be different from either the first rubber member 10 or the second rubber member 20.

[0025] The value of thickness T0 is not particularly limited as long as it is smaller than the value of thickness T2, but when the value of T2 is taken as 100%, it is preferably 35 to 65%, more preferably 40 to 60%, and even more preferably 45 to 55%.

[0026] Fifth Embodiment FIG. 5 shows a perspective view of a fire spread prevention sheet according to a fifth embodiment. A fire spread prevention sheet 1d according to this embodiment has strip portions 40 with a thickness T0, which is smaller than the thickness T2, on two opposing end surfaces of the sheet. The two opposing end surfaces of the sheet are preferably the end surfaces on both ends of the groove. In the fire spread prevention sheet 1d, the strip portions 40 are the same as in the fire spread prevention sheet 1b, and the other structure and materials are the same as in the fire spread prevention sheet 1b.

[0027] (Stress simulation of fire prevention sheet) A stress simulation of the fire spread prevention sheet shown in Figs. 6 to 8 was carried out under the following conditions. (1) Software Marc nonlinear finite element analysis software (manufactured by MSC Software Co., Ltd.) (2) Sample Fire prevention sheet according to the first embodiment (hereinafter referred to as sheet 1). Fire prevention sheet according to the second embodiment (θ=45 degrees) (hereinafter referred to as Sheet 2) Fire prevention sheet according to the second embodiment (θ=60 degrees) (hereinafter referred to as Sheet 3) Fire prevention sheet according to the third embodiment (hereinafter referred to as sheet 4) A rubber sheet consisting of only the first rubber member and having the same thickness as each of the above fire prevention sheets (hereinafter referred to as the conventional example). (3) Rubber First rubber: Type A silicone rubber with a durometer hardness of 70 Second rubber: Type A silicone rubber with a durometer hardness of 30 (4) Sheet size 100mm x 200mm x 4mm (each rubber part is 10mm wide)

[0028] Figure 6 shows the results of a stress simulation for Sheet 1 (6A) and Sheet 2 (6B). Figure 7 shows the results of a stress simulation for Sheet 3 (7A) and Sheet 4 (7B). Figure 8 shows the results of a stress simulation for a conventional example. The stress is displayed in 11 stages using a bar on the left side of each sheet. The bars are set so that stress increases from bottom to top. Specifically, the stress ranges are in 11 stages: 0 to less than 30, 30 to less than 60, 60 to less than 90, 90 to less than 120, 120 to less than 150, 150 to less than 180, 180 to less than 210, 210 to less than 240, 240 to less than 270, 270 to less than 300, and 300 or more (hereinafter and in Figures 6 to 8, these are also referred to as a to k, from bottom to top). The unit of stress is MPa. Hereinafter, units will be omitted.

[0029] The indentation depth of each sheet in the simulation was as follows: Sheet 1: 0.60mm Sheet 2: 0.53mm Sheet 3: 0.50mm Sheet 4: 0.52mm Conventional example: 0.45 mm

[0030] The conventional example had a high proportion of k, i.e., the highest stress points, suggesting that high stress was applied overall.

[0031] On the other hand, as shown in Figures 6 and 7, the fire spread prevention sheets according to the embodiments have a wider region below k than the conventional example, suggesting that the stress is lower than that of the conventional example. This suggests that the fire spread prevention sheets according to the present application are capable of more flexible elastic deformation in response to fluctuations in pressure applied in the thickness direction.

[0032] 2. Manufacturing method of fire prevention sheet First Embodiment FIG. 9 is a schematic diagram showing an example of a method for manufacturing a fire spread prevention sheet. The method for manufacturing a fire spread prevention sheet according to this embodiment includes at least a first lamination step in which a first rubber and a second rubber having a lower rubber hardness than the first rubber are alternately laminated to obtain a laminate. The method may also include a slicing step and / or a groove forming step, which will be described later. FIG. 9 schematically shows the steps for manufacturing a fire spread prevention sheet 1 by performing a slicing step after the first lamination step. Each step will be described in detail below.

[0033] (1) First lamination process The first lamination step is a step of alternately laminating the first rubber 15, which is the base material for the first rubber member 10, and the second rubber 25, which is the base material for the second rubber member 20, to obtain a laminate 50. In this embodiment, the first rubber 15 and the second rubber 25 are already cured. The shapes of the first rubber 15 and the second rubber 25 are not particularly limited, and they may be, for example, sheet-like or block-shaped, such as a rod or columnar shape, but sheet-like is preferred. When both the first rubber and the second rubber are silicone rubber in sheet form, a step of kneading the silicone rubber and a crosslinking agent using a kneader such as a mixing roll, dispensing the resulting sheet, and curing the sheet-shaped product by heat treatment to produce a rubber sheet may be performed in advance. Furthermore, the method for fixing the first rubber 15 and the second rubber 25 during lamination is not particularly limited, and they may be appropriately bonded using a known adhesive or the like. Examples of adhesives that can be used include epoxy-based adhesives, urethane-based adhesives, acrylic-based adhesives, melamine-based adhesives, polyester-based adhesives, and silicone-based adhesives. Among these, it is preferable to use a silicone adhesive, which has excellent heat resistance and rubber elasticity.

[0034] (2) Slicing process The slicing process is a process of slicing the laminate 50 obtained in the first lamination process to a predetermined width in the lamination direction or at an acute angle to the lamination direction. This process completes a fire spread prevention sheet 1 of a predetermined width. This process forms grooves (not shown) on the side of the low-hardness second rubber 25 located at the sliced ​​surface. These grooves can be used as grooves 21 to be provided in the second rubber member 20 on the fire spread prevention sheet 1. This process is optional and may not be performed if adjustment to a predetermined width is not required, for example, when block-shaped first and second rubbers are laminated that have been pre-formed and cut to the same size as the width of the fire spread prevention sheet. The method of slicing the laminate 50 is not particularly limited as long as it can be cut to a predetermined thickness using, for example, a known cutter or slicer. However, slicing using a band machine slicer (a device that rotates a band-shaped blade called a band knife at high speed) or a rotary blade is preferred.

[0035] (3) Groove formation process The groove forming step is a step of forming grooves extending along the longitudinal direction on any end surface of the second rubber. The method of forming the grooves is not particularly limited, and examples include a method of scraping the end surface of the second rubber using a known cutter or the like. This step is optional, but may be performed if the slicing step described above was not performed or if the groove formation was insufficient even after the slicing step. If this step is performed after the first lamination step or the slicing step, a groove is formed on any end surface of the second rubber located on the lamination surface. This step may also be performed in advance on the second rubber before the first lamination step.

[0036] Second Embodiment The manufacturing method of the fire spread prevention sheet according to this embodiment includes a second lamination step of alternately laminating a first uncured rubber, which is the uncured first rubber that will become the first rubber member, and a second uncured rubber, which is the uncured second rubber that will become the second rubber member, and a curing step of curing the uncured laminate after the second lamination step. The difference from the first embodiment is that uncured rubber is used as the material that will become the first rubber member and the second rubber member at the time of lamination.

[0037] (1)Second lamination process The second lamination step is a step of alternately laminating a first uncured rubber, which is the uncured first rubber that will become the first rubber member, and a second uncured rubber, which is the uncured second rubber that will become the second rubber member, to obtain an uncured laminate. The uncured rubber is preferably a solid uncured rubber molded into a specific shape, such as a sheet or a rod, so that it can be subjected to the second lamination step. When the first uncured rubber and the second uncured rubber are silicone rubbers, examples of molding methods include a molding method using a mixing roll, a calendar molding method, and a press molding method.

[0038] (2) Curing process The curing step is a step of curing the uncured laminate obtained in the second lamination step. This step results in a cured laminate in which the first rubber and the second rubber are bonded at their interfaces. When the first rubber and the second rubber are silicone rubbers, the curing method may be addition curing, peroxide curing, or condensation curing, but addition curing, which is cured by heating, is preferred.

[0039] (3) Slicing process The slicing step is the same as that in the first embodiment, except that it is performed on the laminate obtained by the curing step.

[0040] (4) Groove formation process The groove forming step is the same as that of the first embodiment described above, except that it is performed on the laminate obtained by the curing step.

[0041] 3. Battery First Embodiment FIG. 10 shows a longitudinal cross-sectional view (10A) of a battery according to the first embodiment and a schematic plan view (10B) of a fire prevention sheet sandwiched between battery cells and between the battery cells and the housing. The battery 100 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") 200 arranged side by side. The number of battery cells 200 is eight in this embodiment, but may be two to seven, or nine or more. The battery 100 is a storage battery, preferably a lithium-ion battery. The battery 100 includes a housing 110 with a bottom that is open on one side. The battery cells 200 are disposed inside 120 of the housing 110. The plurality of battery cells 200 are preferably held in close contact with each other within the housing 110 by compressive force applied from both sides using screws or the like (not shown). The bottom of the housing 110 is provided with a through-hole 130 for flowing cooling water, an example of a coolant. The coolant may be referred to as a cooling medium or a coolant. The battery cells 200 are arranged in the housing 11 with the fire spread prevention sheets 1, 1a, 1b, 1c, and 1d sandwiched between adjacent battery cells 200. Note that FIG. 10 does not show the openings of the flow paths exposed at the end surfaces of the fire spread prevention sheets 1, 1a, 1b, 1c, and 1d. Hereinafter, in this embodiment, the fire spread prevention sheets 1, 1a, 1b, 1c, and 1d will be collectively referred to as the "fire spread prevention sheet 1."

[0042] As described above, the battery 100 according to the first embodiment includes a plurality of battery cells 200 in the housing 110, and includes the fire spread prevention sheet 1 at least between the battery cells 200, between the battery cells 200 and between the battery cells 200 and the housing 110. The fire spread prevention sheet 1 is disposed with its thickness direction sandwiched between the battery cells 200 and between the battery cells 200 and the housing 110. The fire spread prevention sheet 1 is disposed so that its length direction is the length direction of the battery cells 200 (the vertical direction in the drawing) or is disposed so that it is the width direction of the battery cells 200 (the front-to-back direction in the drawing). The fire spread prevention sheet 1 does not have to be disposed between the battery cells 200 and the housing 110.

[0043] The fire spread prevention sheet 1 disposed between the battery cells 200 is a sheet having a configuration in which first rubber members 10 and second rubber members 20 are alternately laminated in the width direction. The fire spread prevention sheet 1 is sandwiched and compressed between the battery cells 200 when the battery cells 200 are set in the housing 110, and even if the situation of subsequently releasing the compression is repeated many times, the fire spread prevention sheet 1 elastically deforms in its thickness direction and easily recovers to its original thickness. Furthermore, the fire spread prevention sheet 1 is compressed in its thickness direction when it is stored in the housing 110 in a compressed state between the battery cells 200, and is further compressed when the battery cells 200 heat up and expand during subsequent charging and / or discharging of the battery 100. The second rubber member 20 is configured so that the thickness of part or all of it is smaller than the thickness of the first rubber member 10, and has grooves extending in the longitudinal direction at any position in the width direction thereof, so that when it is sandwiched between the battery cells 200 and compressed, it is possible to form a gap 150 (shown by hatching in FIG. 10B ) between the second rubber member 20 and the battery cells 200. As a result, when some of the battery cells 200 overheat, the fire spread prevention sheet 1 has the function of more efficiently reducing heat transfer from the overheated battery cells 200 to adjacent battery cells 200 by the air layer in the gap 150, thereby preventing the spread of fire.

[0044] Second Embodiment FIG. 11 shows a longitudinal cross-sectional view of a battery according to the second embodiment. In the battery 100a according to this embodiment, the fire spread prevention sheets 1 provided between the battery cells 200 and between the battery cells 200 and the housing 110, at least between the battery cells 200, are replaced with the above-described fire spread prevention sheets 1c. This creates gaps between the battery cells 200 and the fire spread prevention sheets 1c due to the pieces 40, ensuring airflow and achieving better heat insulation performance. The other structure and materials of the battery 100a are the same as those of the battery 100.

[0045] 3. 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.

[0046] The features of the claims may be combined in any combination except where they are incombinable with one another. [Industrial Applicability]

[0047] The present invention can be used in the field of preventing the spread of fire caused by an overheated state of a heat source. [Explanation of symbols]

[0048] 1,1a,1b,1c,1d···Fire prevention sheet, 10···First rubber member, 15···First rubber, 20···Second rubber member, 21···Groove, 25···Second rubber, 30···Interface, 40···Single portion, 50···Laminated body, 100,100a···Battery, 110···Housing, 200···Battery cell.

Claims

1. A fire prevention sheet that is disposed at least between a plurality of heat sources and that can prevent the spread of fire by suppressing heat transfer to other heat sources when the heat sources are in an overheated state, a sheet having a first rubber member and a second rubber member having a rubber hardness lower than that of the first rubber member, stacked alternately in a width direction of the sheet in one direction within the plane of the sheet; The second rubber member is configured so that a part or all of its thickness is smaller than a thickness of the first rubber member, A fire spread prevention sheet characterized in that the second rubber member has a groove extending along the longitudinal direction at any position in the width direction thereof.

2. 2. The fire spread prevention sheet according to claim 1, wherein the first rubber member has a thickness at any position in the width direction thereof that is greater than the thickness of any part of the second rubber member.

3. The fire spread prevention sheet according to claim 1, wherein the first rubber member and the second rubber member are laminated together with their inclined surfaces inclined with respect to the thickness direction of the fire spread prevention sheet.

4. The fire spread prevention sheet according to claim 1, characterized in that the fire spread prevention sheet has, on two opposing end surfaces of the sheet, pieces having a thickness smaller than that of the fire spread prevention sheet.

5. 5. The fire spread prevention sheet according to claim 4, wherein the two opposing sheet end faces are end faces on both ends of the groove.

6. A method for producing the fire spread prevention sheet according to any one of claims 1 to 5, A method for manufacturing a fire spread prevention sheet, comprising a first lamination step of alternately laminating a first rubber that is the basis for the first rubber member and a second rubber that is the basis for the second rubber member.

7. A method for producing the fire spread prevention sheet according to any one of claims 1 to 5, a second lamination step of alternately laminating a first uncured rubber, which is the first rubber that is the base of the first rubber member and is in an uncured state, and a second uncured rubber, which is the second rubber that is the base of the second rubber member and is in an uncured state; a curing step of curing the uncured laminate after the second lamination step.

8. The method for manufacturing a fire spread prevention sheet according to claim 6, further comprising a slicing step of slicing the laminate obtained by the first lamination step to a predetermined width in the lamination direction or at an acute angle to the lamination direction.

9. The method for manufacturing a fire spread prevention sheet according to claim 7, further comprising a slicing step of slicing the laminate obtained by the curing step to a predetermined width in the lamination direction or at an acute angle to the lamination direction.

10. A battery having a plurality of battery cells in a housing, A battery comprising the fire spread prevention sheet according to any one of claims 1 to 5, at least between the battery cells, among between the battery cells and between the battery cells and the housing.

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