Fire spread preventing sheet and battery including the same

Abstract

To provide a fire spread preventing sheet having high heat insulation property and high cushioning property, and a battery including the same.SOLUTION: There are provided a fire spread preventing sheet 1a, which is arranged at least between a plurality of heat sources, suppresses heat transfer to other heat source when the heat sources are overheated and can prevent fire spread, has one or more storage parts 4 storing air, and a flow channel 5 passing air toward the end of a rubber or resin sheet body 3 from the storage parts 4 provided on the sheet body 3, wherein the storage part 4 is a through hole penetrating in a thickness direction of the sheet body 3 or a recess recessed in the thickness direction; and a battery including the same.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fire prevention sheet and a battery equipped with 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 expand when overheated during discharge and / or charging. For this reason, ceramic sheets with high hardness, even if they have excellent fire resistance, are not suitable for preventing fire spread between cells. Generally, when a resin cushion is compressed, the compressive stress depends on the hardness of the cushion. The conventionally known fire spread prevention member disclosed in Patent Document 1 is a single-layer fire-resistant material formed from a urethane resin composition. A simple resin sheet lacks heat insulation properties.

[0006] Prior to the present invention, the inventors manufactured resin or rubber sheets with multiple through-holes penetrating the sheet thickness direction and evaluated their thermal insulation and cushioning properties. When the sheet is sandwiched between cells, the air in the through-holes provides high thermal insulation, resulting in higher thermal insulation than a simple resin or rubber sheet. However, when pressure is applied from the cells on both sides of the sheet, the walls of the through-holes deform, reducing the volume of the through-holes themselves. As a result, the air in the through-holes is compressed and its volume is reduced. This results in a decrease in the thermal insulation properties of the sheet. In addition, it has been found that if the air pressure in the through-holes becomes too high, the cushioning properties of the sheet are also reduced. There is a market demand for fire-retardant sheets with high thermal insulation and cushioning properties. Meeting this demand will also contribute to the applicant's sustainable development goal of "ensuring access to affordable, reliable, sustainable, and modern energy for all."

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a fire spread prevention sheet having high heat insulation and high cushioning properties, and a battery equipped with the same. [Means for solving the problem]

[0008] (1) In order to achieve the above object, one embodiment of a fire spread prevention sheet is a fire spread 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 rubber or resin sheet body is one or more reservoirs for storing air; a flow path for passing air from the storage portion toward an end portion of the seat body; Equipped with The storage portion is a through-hole that penetrates the sheet body in the thickness direction or a recess that is recessed in the thickness direction. (2) In another embodiment, the fire spread prevention sheet preferably includes a plurality of the storage sections, and the flow path may be formed by connecting the plurality of storage sections and extending to the end of the sheet body. (3) In the fire spread prevention sheet according to another embodiment, the flow path may preferably be a groove formed on at least one surface of the sheet body in the thickness direction. (4) In another embodiment of the fire spread prevention sheet, preferably, the shape of the widest surface of the sheet body is rectangular, and multiple grooves may be formed intersecting each other on the widest surface. (5) In another embodiment of the fire spread prevention sheet, preferably, a piece having a thickness smaller than that of the sheet body is provided on at least one end side of the sheet body, The piece portion has a step with respect to the widest surface of the seat body, The groove may be open to a surface of the step in the thickness direction. (6) In another embodiment of the fire spread prevention sheet, preferably, The grooves are formed on both surfaces of the sheet body in the thickness direction, The plurality of grooves formed on both surfaces may be formed so that their inner bottom surfaces are offset from one another on a straight line in the thickness direction of the sheet main body. (7) In the fire spread prevention sheet according to another embodiment, the sheet body may preferably be a silicone rubber sheet. (8) To achieve the above object, a battery according to one embodiment includes a plurality of battery cells in a housing, Any 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]

[0009] According to the present invention, it is possible to provide a fire spread prevention sheet having high heat insulation properties and high cushioning properties, and a battery including the same. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows a perspective view of a fire spread prevention sheet according to the first embodiment. [Figure 2] FIG. 2 shows a perspective view of a fire spread prevention sheet according to the second embodiment. [Figure 3] FIG. 3 shows a perspective view of a fire spread prevention sheet according to a third embodiment. [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 a perspective view of a fire spread prevention sheet according to a sixth embodiment. [Figure 7] Figure 7 shows a perspective view of a fire spread prevention sheet according to the first embodiment and the results of a simulation of the same sheet (7A), and a perspective view of a fire spread prevention sheet according to the second embodiment and the results of a simulation of the same sheet (7B). [Figure 8] Figure 8 shows an oblique view of a fire spread prevention sheet according to the third embodiment and the results of a simulation of the same sheet (8A), and an oblique view of a fire spread prevention sheet according to the fourth embodiment and the results of a simulation of the same sheet (8B). [Figure 9] FIG. 9 shows a perspective view of a first comparative sheet not according to the present invention and the results of a simulation of the same sheet (9A), and a perspective view of a second comparative sheet not according to the present invention and the results of a simulation of the same sheet (9B). [Figure 10] FIG. 10 shows a longitudinal cross-sectional view of a battery according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] 1. Fire prevention sheet First Embodiment FIG. 1 shows a perspective view of a fire spread prevention sheet according to the first embodiment.

[0013] The fire spread prevention sheet 1a 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, heaters or their components, and components in electrical or electronic devices (circuit boards, circuit components, etc.).

[0014] The fire spread prevention sheet 1a is provided with a rubber or resin sheet main body 3, which includes one or more storage sections 4 for storing air, and flow paths 5 for passing air from the storage sections 4 toward the ends of the sheet main body 3 (i.e., the ends of the fire spread prevention sheet 1a). The flow paths 5 connect the storage sections 4 to the ends of the sheet main body 3. The storage sections 4 are through-holes that penetrate the sheet main body in the thickness direction or recesses that are recessed in the thickness direction. In this embodiment, the storage sections 4 are through-holes that penetrate the sheet main body 3 in the thickness direction, and multiple storage sections 4 are provided in the sheet main body 3. More specifically, a total of 60 through-holes are formed in the fire spread prevention sheet 1a. However, the number of through-holes is not limited to 60, and may be 1, 2 to 59, or 61 or more. In addition, recesses may be provided as the storage sections 4 instead of through-holes.

[0015] In this embodiment, the flow paths 5 connect multiple storage sections 4 and extend to the ends of the sheet body 3. The fire spread prevention sheet 1a is preferably a sheet in which the widest surface of the sheet body 3 is rectangular. More specifically, the widest surface of the fire spread prevention sheet 1a is rectangular. Eight flow paths 5 are formed parallel to the long sides of the rectangle in the thickness direction on both sides of the rectangle. However, the number of flow paths 5 is not limited to eight, and may be one, two to seven, or nine or more. In this embodiment, the flow paths 5 are grooves formed on both sides of the sheet body 3 in the thickness direction. However, the flow paths 4 are not necessarily limited to the shape of a groove, and may be in the form of a tunnel passing through the inside of the sheet body 3. The flow paths 4 may be formed on only one side of the sheet body 3 in the thickness direction. The multiple grooves formed on both sides of the sheet body 3 in the thickness direction are formed so that the inner bottom surfaces of the grooves are aligned in a straight line in the thickness direction of the sheet body 3. The width of the groove is preferably smaller than one side when the opening surface of the storage section 4 is rectangular, and smaller than the diameter when the opening surface is circular. The depth of the groove is preferably less than half the thickness of the sheet body 3 .

[0016] The main sheet body 3 is a resin or rubber sheet, and is preferably made of 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 is more preferably used because of its relatively high heat resistance.

[0017] The thickness of the fire spread prevention sheet 1a is not particularly limited, but is preferably 1 to 40 mm, more preferably 2 to 15 mm. The width of the fire spread prevention sheet 1a is also not particularly limited, but is preferably 50 to 300 mm, more preferably 80 to 150 mm. The length of the fire spread prevention sheet 1a is also not particularly limited, but is longer than the width and is preferably 200 to 700 mm, more preferably 300 to 600 mm.

[0018] The storage section 4 is a region for storing air when the fire spread prevention sheet 1a is sandwiched between multiple heat sources from both sides in the thickness direction, or when the fire spread prevention sheet 1a is sandwiched between a heat source and a member other than the heat source (for example, a battery housing). By storing air with low thermal conductivity, i.e., high thermal insulation, in the storage section 4, the thermal insulation of the fire spread prevention sheet 1a can be further improved.

[0019] When the fire spread prevention sheet 1a is sandwiched between heat sources or between components other than heat sources, it is compressed in the thickness direction as the heat sources expand. The air in the storage section 4 is compressed and pressurized. At this time, the pressurized air in the storage section 4 flows to the outside through the flow paths 5 (see arrow A in Figure 1). Note that in Figure 1, arrows A are not drawn on all flow paths 5. The same applies to Figure 2 and subsequent figures. In this way, because the storage section 4 is connected to the outside of the fire spread prevention sheet 1a, the pressure in the storage section 4 does not become excessively high. This allows the fire spread prevention sheet 1a to maintain high cushioning properties. Furthermore, because the fire spread prevention sheet 1a can retain air in the storage section 4 and flow paths 5 even when compressed, it can maintain high thermal insulation properties. Note that when the fire spread prevention sheet 1a returns to its original thickness from the compressed state, air enters the storage section 4 from the outside through the flow paths 5.

[0020] Next, an example of a method for manufacturing the fire spread prevention sheet 1a will be described. In this manufacturing method, a curable composition, preferably a curable rubber composition, more preferably a curable silicone rubber composition, is placed in a mold and molded into a sheet shape while forming through-holes as the storage portions 4 and grooves as the flow paths 5. During molding, the curable composition is also heated to a degree that allows it to harden. Another manufacturing method is a method in which a sheet is molded into a sheet shape while forming grooves as the flow paths 5, and then through-holes are formed as the storage portions 4. The above manufacturing method is also applicable to the case in which recesses are formed as the storage portions 4. Furthermore, when the flow paths 5 pass through the inside of the sheet main body 3, grooves may be formed in the same positions in two sheets and the sheets are then bonded together to achieve groove integration.

[0021] In the above exemplary manufacturing method, a thermosetting composition is used as the curable composition, but a thermoplastic material or a photocurable material may also be used as the curable composition. In this case, a method of cooling the thermoplastic material in the mold or a method of irradiating the photocurable material in the mold with light can be used.

[0022] Second Embodiment FIG. 2 shows a perspective view of a fire spread prevention sheet according to the second embodiment.

[0023] In the fire spread prevention sheet 1b according to this embodiment, the grooves serving as flow paths 5 formed on both sides of the sheet in the thickness direction are formed at positions different from those of the first embodiment. Other structures, materials, manufacturing methods, etc. of the fire spread prevention sheet 1b are the same as those of the fire spread prevention sheet 1a. Below, the differences between the fire spread prevention sheet 1b and the fire spread prevention sheet 1a will be described.

[0024] In the fire spread prevention sheet 1b, grooves are formed on both sides in the thickness direction of the sheet body 3. The multiple grooves formed on both sides are formed so that their inner bottom surfaces are offset from one another from a straight line in the thickness direction of the sheet body 3. This makes it possible to design the depth of the grooves to exceed 50% of the thickness of the sheet body 3.

[0025] <Third embodiment> FIG. 3 shows a perspective view of a fire spread prevention sheet according to a third embodiment.

[0026] In the fire spread prevention sheet 1c according to this embodiment, the direction of the grooves serving as the flow paths 5 is different from that of the first embodiment. Other structures, materials, manufacturing methods, etc. of the fire spread prevention sheet 1c are the same as those of the fire spread prevention sheet 1a. Below, we will explain the differences between the fire spread prevention sheet 1c and the fire spread prevention sheet 1a.

[0027] In the fire spread prevention sheet 1c, the grooves are formed so that the widest surface is parallel to the short side of the rectangular sheet body 3. Therefore, when the fire spread prevention sheet 1c is compressed in the thickness direction, the air in the storage section 4 escapes to the outside from the long side of the sheet body 3 (see arrow A in Figure 3).

[0028] <Fourth embodiment> FIG. 4 shows a perspective view of a fire spread prevention sheet according to a fourth embodiment.

[0029] In the fire spread prevention sheet 1d according to this embodiment, the direction of the grooves serving as the flow paths 5 is different from that of the first embodiment. Other structures, materials, manufacturing methods, etc. of the fire spread prevention sheet 1d are the same as those of the fire spread prevention sheet 1a. Below, the differences between the fire spread prevention sheet 1d and the fire spread prevention sheet 1a will be described.

[0030] In the fire spread prevention sheet 1d, the grooves are arranged so that the widest surface is parallel to the short sides of the rectangular sheet body 3 and also parallel to the long sides of the sheet body 3. That is, in the fire spread prevention sheet 1d, the shape of the widest surface of the sheet body 3 is rectangular (preferably rectangular), and multiple grooves are formed to intersect on that widest surface. The formation of such grooves is a combination of the formation of grooves in the first and third embodiments. Therefore, when the fire spread prevention sheet 1d is compressed in its thickness direction, the air in the storage section 4 escapes to the outside from both the long and short sides of the sheet body 3 (see arrow A in FIG. 4).

[0031] Fifth Embodiment FIG. 5 shows a perspective view of a fire spread prevention sheet according to a fifth embodiment.

[0032] The fire spread prevention sheet 1e according to this embodiment differs from the first embodiment in the shape of both short sides of the fire spread prevention sheet 1e and the number of storage sections 4. Other structures, materials, manufacturing methods, etc. of the fire spread prevention sheet 1e are the same as those of the fire spread prevention sheet 1a. Below, we will explain the differences between the fire spread prevention sheet 1e and the fire spread prevention sheet 1a.

[0033] The fire spread prevention sheet 1e has a piece 6 on at least one end of the sheet body 3 that is thinner than the sheet body 3. More specifically, the fire spread prevention sheet 1e has a piece 6 on both short sides of the sheet body 3 (both short sides of the fire spread prevention sheet 1e) that form the storage sections 4, and the piece 6 is thinner than the sheet body 3. The piece 6 has a step 7 on the widest surface of the sheet body 3. The grooves serving as the flow paths 5 open on the surface facing the step 7 in the thickness direction. The step 7 is preferably formed on both sides of the sheet body 3 in the thickness direction. However, if the grooves are formed on only one surface of the sheet body 3 in the thickness direction, the step 7 may be formed on only that surface. In the fire spread prevention sheet 1e, the area of ​​the sheet body 3 is smaller than in the first embodiment due to the presence of the piece 6. As a result, the number of storage sections 4 is reduced from 60 in the first embodiment to 52.

[0034] By providing the above-mentioned piece 6, even if the short side of the fire spread prevention sheet 1e abuts against another member, when the fire spread prevention sheet 1e is compressed in the thickness direction or released from compression, air can easily flow from the storage section 4 to the outside through the groove, or in the opposite direction. The length of the piece 6 is preferably 5% to 25% of the longitudinal distance (=length) of the fire spread prevention sheet 1e, and more preferably 10% to 20%.

[0035] Sixth Embodiment FIG. 6 shows a perspective view of a fire spread prevention sheet according to a sixth embodiment.

[0036] The fire spread prevention sheet 1f according to this embodiment differs from the first embodiment in the shape of both long sides of the fire spread prevention sheet 1f and the number of storage sections 4. Other structures, materials, manufacturing methods, etc. of the fire spread prevention sheet 1f are the same as those of the fire spread prevention sheet 1a. Below, we will explain the differences between the fire spread prevention sheet 1f and the fire spread prevention sheet 1a.

[0037] The fire spread prevention sheet 1f has a piece 6 on at least one end of the sheet body 3 that is thinner than the sheet body 3. More specifically, the fire spread prevention sheet 1f has piece 6 on both long sides of the sheet body 3 (both long sides of the fire spread prevention sheet 1f) that form the storage sections 4, and the piece 6 is thinner than the sheet body 3. The piece 6 has a step 7 on the widest surface of the sheet body 3. The grooves serving as the flow paths 5 open on the surface facing the step 7 in the thickness direction. The step 7 is preferably formed on both sides of the sheet body 3 in the thickness direction. However, if the grooves are formed on only one surface of the sheet body 3 in the thickness direction, the step 7 may be formed on only that surface. In the fire spread prevention sheet 1f, the area of ​​the sheet body 3 is smaller than in the first embodiment due to the presence of the piece 6. As a result, the number of storage sections 4 is reduced from 60 in the first embodiment to 45.

[0038] By providing the above-mentioned piece 6, even if the long side of the fire spread prevention sheet 1f abuts against another member, when the fire spread prevention sheet 1f is compressed in the thickness direction or released from compression, air can easily flow from the storage section 4 to the outside through the groove, or in the opposite direction. The length of the piece 6 is preferably 3% to 25% of the width of the fire spread prevention sheet 1f, and more preferably 5% to 20%.

[0039] Next, the results of stress simulations of the fire spread prevention sheets 1a, 1b, 1c, and 1d according to the first to fourth embodiments will be explained using sheets 100a and 100b outside the present invention for comparison.

[0040] Fig. 7 shows a perspective view of a fire spread prevention sheet according to the first embodiment and the results of a simulation of the same sheet (7A), and a perspective view of a fire spread prevention sheet according to the second embodiment and the results of a simulation of the same sheet (7B). Fig. 8 shows a perspective view of a fire spread prevention sheet according to the third embodiment and the results of a simulation of the same sheet (8A), and a perspective view of a fire spread prevention sheet according to the fourth embodiment and the results of a simulation of the same sheet (8B). Fig. 9 shows a perspective view of a first comparative sheet not according to the present invention and the results of a simulation of the same sheet (9A), and a perspective view of a second comparative sheet not according to the present invention and the results of a simulation of the same sheet (9B).

[0041] The stress simulations shown in Figures 7 to 9 were performed using Marc nonlinear finite element analysis software manufactured by MSC Software Corporation. The fire spread prevention sheets 1a, 1b, 1c, and 1d, the first comparative sheet 100a, and the second comparative sheet 100b were all sheets of the same shape, dimensions, and material. Specifically, the dimensions of each sheet were 100 mm wide, 200 mm long, and 4 mm thick. Each sheet was made of silicone rubber (hardness: Shore A hardness 50° according to JIS K 6253). The first comparative material 100a was a simple plate-like sheet without a reservoir 4 or flow path 5. The second comparative material 100b was a sheet with through holes as reservoirs 4 but without flow paths 5. The stress simulations were performed at four indentation distances: 0.45 mm, 0.63 mm, 0.67 mm, and 0.90 mm. The results of the stress simulation shown in Figures 7 to 9 are shown as stress distributions in plan view (=field of view viewing the widest surface) of fire spread prevention sheets 1a, 1b, 1c, 1d, first comparative sheet 100a, and second comparative sheet 100b.

[0042] (7A) shows the stress simulation result 8a of the fire spread prevention sheet 1a. (7B) shows the stress simulation result 8b of the fire spread prevention sheet 1b. (8A) shows the stress simulation result 8c of the fire spread prevention sheet 1c. (8B) shows the stress simulation results 8d1 and 8d2 of the fire spread prevention sheet 1d. (9A) shows the stress simulation result 108a of the first comparative sheet 100a. (9B) shows the stress simulation result 108b of the second comparative sheet 100b.

[0043] Stress is displayed in stages (12 stages) using a bar on the left side of each sheet. The bar is set so that stress increases from bottom to top. Specifically, the stress ranges are in 12 stages: 0 or more but less than 30, 30 or more but less than 60, 60 or more but less than 90, 90 or more but less than 120, 120 or more but less than 150, 150 or more but less than 180, 180 or more but less than 210, 210 or more but less than 240, 240 or more but less than 270, 270 or more but less than 300, and 300 or more. The unit of stress is MPa. From here on, units will be omitted.

[0044] When fire spread prevention sheets 1a, 1b, 1c, and 1d were compressed in the thickness direction to a compression length of 0.67 mm, the stress on the sheet surface was maintained at a low level. Furthermore, in fire spread prevention sheets 1a, 1b, and 1c, the storage section 4 showed higher stress than the sheet surface, but did not exceed 300. Furthermore, the grooves serving as flow paths 5 showed lower stress than the sheet surface. It is believed that the air in the storage section 4 is compressed and flows to the outside through the grooves, maintaining an air layer in the grooves. When fire spread prevention sheet 1d was compressed in the thickness direction to a compression length of 0.90 mm, the storage section 4 and its vicinity showed higher stress than the sheet surface, but the stress did not exceed 300.

[0045] On the other hand, when the first comparative sheet 100a was compressed in the thickness direction to a pressing length of 0.45 mm, almost the entire sheet surface exhibited a stress value exceeding 300. When the second comparative sheet 100b was compressed in the thickness direction to a pressing length of 0.63 mm, the sheet surface other than the storage section 4 exhibited a low stress value, but the storage section 4 and its vicinity exhibited a stress value exceeding 300.

[0046] From the above results, it is believed that the flow paths 5 formed in the fire spread prevention sheets 1a, 1b, 1c, and 1d have the function of dispersing the stress acting on each sheet and the function of retaining air within the flow paths 5.

[0047] 2. Battery FIG. 10 shows a longitudinal cross-sectional view of a battery according to one embodiment.

[0048] The battery 10 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") 20 arranged side by side. In this embodiment, the number of battery cells 20 is eight, but may be two to seven, or nine or more. The battery 10 is a storage battery, preferably a lithium-ion battery. The battery 10 includes a housing 11 with a bottom that is open on one side. The battery cells 20 are disposed inside 12 of the housing 11. The plurality of battery cells 20 are preferably pressed against each other by applying compressive force from both sides of the housing 11 using screws or the like (not shown). The bottom of the housing 11 is provided with a through-hole 13 for flowing cooling water, which is an example of a coolant. The coolant may also be referred to as a cooling medium or a coolant. The battery cells 20 are disposed inside the housing 11 with a fire-prevention sheet 1a sandwiched between adjacent battery cells 20.

[0049] As described above, the battery 10 includes a plurality of battery cells 20 in the housing 11, and includes the fire prevention sheet 1a between the battery cells 20 and between the battery cells 20 and the housing 11, at least between the battery cells 20. The fire prevention sheet 1a does not have to be disposed between the battery cells 20 and the housing 11.

[0050] The fire spread prevention sheet 1a disposed between the battery cells 20 is sandwiched and compressed between the battery cells 20 when the battery cells 20 are set in the housing 11, and even if the situation of subsequent release of compression is repeated many times, the fire spread prevention sheet 1a elastically deforms in its thickness direction and recovers to its original thickness. Furthermore, the fire spread prevention sheet 1a is compressed in its thickness direction when it is stored in the housing 11 in a compressed state between the battery cells 20, and is further compressed when the battery cells 20 heat and expand during subsequent charging and / or discharging of the battery 10. In addition to having the function of preventing fire spread by reducing heat transfer from an overheated battery cell 20 to an adjacent battery cell 20 when some battery cells 20 overheat, the fire spread prevention sheet 1a can deform without excessive resistance to multiple stages of compression within the battery 10, and maintains high thermal insulation by dispersing air in the flow paths.

[0051] Instead of fire spread prevention sheet 1a, any of fire spread prevention sheets 1b, 1c, 1d, 1e, and 1f may be provided inside battery 10. Also, two or more of fire spread prevention sheets 1a, 1b, 1c, 1d, 1e, and 1f may be combined and provided inside battery 10.

[0052] 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.

[0053] For example, the flow paths 5 are not limited to grooves, and may be tunnel-shaped flow paths that run from the storage section 4 through the inside of the sheet main body 3 to the end. The flow paths 5 may be formed to extend in either the length direction or width direction of the fire spread prevention sheets 1a, 1b, 1c, 1d, 1e, and 1f. The flow paths 5 do not necessarily have to be in the same direction or in the same number on both sides, and may be formed in different directions or in different numbers. In addition, the shape of the flow paths 5 is not limited to a linear shape, and may be any shape, such as a bent shape or a curved shape. In addition, the side portions 6 may be formed around the outer periphery of the sheet main body 3.

[0054] The features of the claims may be combined in any combination except where they are incombinable with one another. [Industrial Applicability]

[0055] 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]

[0056] 1a, 1b, 1c, 1d, 1e, 1f... Fire prevention sheet, 3... Sheet body, 4... Storage section (one example is a through hole), 5... Flow path (one example is a groove), 6... Side portion, 7... Step, 10... Battery, 11... Housing, 20... Battery cell (one example of a heat source).

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, The rubber or resin sheet body is one or more reservoirs for storing air; a flow path for passing air from the storage portion toward an end portion of the seat body; Equipped with A fire spread prevention sheet characterized in that the storage portion is a through hole that penetrates the thickness direction of the sheet body or a recess that is recessed in the thickness direction.

2. A plurality of the storage sections are provided, The fire spread prevention sheet according to claim 1, wherein the flow path is formed by connecting a plurality of the storage sections and extending to an end of the sheet body.

3. 2. The fire spread prevention sheet according to claim 1, wherein the flow path is a groove formed on at least one surface of the sheet body in the thickness direction.

4. The shape of the widest surface of the sheet body is rectangular, 4. The fire spread prevention sheet according to claim 3, wherein a plurality of the grooves are formed so as to intersect on the widest surface.

5. a piece having a thickness smaller than that of the sheet body on at least one end side of the sheet body; The piece portion has a step with respect to the widest surface of the seat body, The fire spread prevention sheet according to claim 3, wherein the grooves are open to a surface of the step in the thickness direction.

6. The grooves are formed on both surfaces of the sheet body in the thickness direction, The fire spread prevention sheet described in claim 3, characterized in that the multiple grooves formed on both sides are formed so that their inner bottom surfaces are positioned offset from each other in a straight line in the thickness direction of the sheet body.

7. 2. The fire prevention sheet according to claim 1, wherein the sheet body is a silicone rubber sheet.

8. 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 7, at least between the battery cells, among between the battery cells and between the battery cells and the housing.

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