Fire-prevention member, manufacturing method for the same, and battery

Abstract

To provide a fire-prevention member that combines high thermal insulation performance, excellent flexibility, and high strength, and a battery including the same.SOLUTION: A rubber-like fire-prevention member 10 that is arranged between a plurality of battery cells 20 inside a battery 30 and is capable of preventing fire from spreading by suppressing heat transfer to the other battery cells 20 when the battery cells 20 are in a state of overheating, includes an end part member 11 located at both ends of the fire-prevention member 10 in the length direction and an inner member 12 located in an inner region sandwiched by both ends and having a lower hardness than the end part member 11. The battery 30 includes the rubber-like fire-prevention member 10.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a fire spread prevention member, a manufacturing method thereof, and a battery equipped with a fire spread prevention member. [Background technology]

[0002] Automobiles have changed from the era when engines were the only power source to hybrid cars equipped with both engines and batteries, and further to electric cars equipped with only batteries. There are many types of batteries for automobiles, among which lithium-ion batteries are widely used. Lithium-ion batteries generally have multiple cells. Each cell has a form in which electrodes are provided in a container containing a solution. When charging and discharging the battery, the cell itself may overheat. In addition, since the battery is mounted in a place such as an automobile that is subject to vibration and sudden acceleration, it is necessary to prevent damage and misalignment of the cells. In response to such a demand, the inventor of the present application developed a fire prevention member made mainly of foamed silicone rubber between cells prior to the present invention (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-156468 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above fire prevention members are required to have the following functions. The first is that they have high insulation or flame retardancy. This performance is required because it is necessary to prevent fire from spreading between cells. The second is that they have excellent flexibility. This performance is required because it is necessary to prevent damage to the cells by deforming in accordance with the expansion of the overheated cells. The third is that they have high strength as a structural member. This performance is required because it is necessary to prevent damage to the cells or displacement caused by vibration or sudden acceleration.

[0005] High thermal insulation or high flame retardancy can be easily achieved by using ceramics such as alumina. However, ceramics have the drawback of lacking flexibility. For this reason, heat-resistant rubber, which has high thermal insulation or flame retardancy as well as excellent flexibility, is a promising candidate. However, flexibility and high strength are in a trade-off relationship, and it is difficult to achieve both flexibility and high strength at the same time, so there is a strong demand for a fire spread prevention member made of heat-resistant rubber that has both flexibility and high strength. The present inventor investigated which parts of an overheated cell are prone to expansion, and proceeded with the development of a fire spread prevention member made of fire-resistant rubber that has both flexibility and high strength, which led to the completion of the present invention.

[0006] The present invention has been made to solve the above problems, and has an object to provide a fire spread prevention member that combines high thermal insulation performance, excellent flexibility and high strength, and a battery equipped with the same. [Means for solving the problem]

[0007] (1) In order to achieve the above object, one embodiment of a fire spread prevention member is a rubber-like fire spread prevention member that is disposed between a plurality of battery cells inside a battery and is capable of preventing the spread of fire by suppressing heat transfer to the other battery cells when the battery cell is in an overheated state, end members located at both ends in the longitudinal direction of the fire spread prevention member; an inner member located in an inner region between the both ends and having a lower hardness than the end members; Equipped with. (2) In the fire spread prevention member according to another embodiment, preferably, The fire spread prevention member has a rectangular parallelepiped shape, The fire spread prevention member is a member arranged such that the longest side of the rectangular parallelepiped corresponds to a height or width of the battery cell, end members located at both ends in the longitudinal direction of the rectangular parallelepiped; an inner member located in an inner region between the both ends and having a lower hardness than the end members; It may also be provided with: (3) In another embodiment of a fire spread prevention member, the end members preferably extend on both sides of the fire spread prevention member in the width direction, which is the next longest after the length direction, and are formed on the inner and outer peripheral parts of the surface of the fire spread prevention member, and the inner member may be formed on the inside of the inner and outer peripheral parts of the surface. (4) In the fire spread prevention member according to another embodiment, preferably, of the end member and the inner member, at least the inner member may be a porous body. (5) In the fire spread prevention member according to another embodiment, the end member may be a first silicone rubber, and the inner member may be a second silicone rubber having a lower hardness than the first silicone rubber. (6) In the fire spread prevention member according to another embodiment, of the first silicone rubber and the second silicone rubber, at least the second silicone rubber may preferably be a porous sponge-like silicone rubber. (7) A method for producing a fire spread prevention member according to one embodiment for achieving the above object is a method for producing any one of the above fire spread prevention members, comprising the steps of: A first blending step of blending raw materials for end members located at both ends in the longitudinal direction of the fire spread prevention member; A first sheeting step of forming the mixture into a sheet after the first blending step; a second blending step of blending raw materials for an inner member located in an inner region between the both ends and having a lower hardness than the end members; A second sheeting step of forming the mixture into a sheet after the second blending step; a joining step of joining the sheet after the first sheeting step and the sheet after the second sheeting step; a vulcanization step of vulcanizing and hardening the sheet after the joining step; Includes. (8) In order to achieve the above-mentioned object, one embodiment of a battery is a battery equipped with any of the fire spread prevention members described above, and has a structure in which the fire spread prevention member is sandwiched between at least a plurality of battery cells within the battery. Effect of the Invention

[0008] According to the present invention, it is possible to obtain a fire spread prevention member that combines high heat insulating performance, excellent flexibility and high strength, and a battery including the same. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 shows a perspective view of a situation in which a fire prevention member according to one embodiment is disposed between battery cells. [Diagram 2] FIG. 2 is a partially see-through perspective view showing a state in which a plurality of battery cells are set in a battery casing with the fire spread prevention member of FIG. 1 sandwiched between the battery cells. [Diagram 3] FIG. 3 is a vertical cross-sectional view showing a state in which a plurality of battery cells are set in a battery housing. [Figure 4] FIG. 4 is a schematic diagram showing an enlarged cross-sectional view of a state in which a battery cell in the battery of FIG. 2 overheats and expands. [Diagram 5] FIG. 5 shows a perspective view (5A) of a first modified example in which the fire spread prevention member and battery cell orientation are different from those in FIG. 1, and a perspective view (5B) of a fire spread prevention member according to a second modified example having a different configuration from that of the fire spread prevention member in FIG. [Figure 6] FIG. 6 shows a flow of main manufacturing steps of a manufacturing method for a fire spread prevention member according to one embodiment. [Figure 7] FIG. 7 shows the morphology and evaluation results of each sample of the examples and comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below does not limit the invention according to the claims, and all of the elements and combinations thereof described in the embodiment are not necessarily essential to the solution of the present invention.

[0011] 1. Fire prevention materials and batteries

[0012] FIG. 1 shows a perspective view of a situation in which a fire prevention member according to one embodiment is disposed between battery cells.

[0013] The fire spread prevention member 10 according to one embodiment is a rubber-like fire spread prevention member that is disposed between a plurality of battery cells 20 inside a battery and that can prevent the spread of fire by suppressing heat transfer to other battery cells 20 when a battery cell 20 is in an overheated state. The fire spread prevention member 10 includes end members 11 located at both ends in the length direction of the fire spread prevention member 10, and an inner member 12 that is located in an inner region sandwiched between the both ends and has a lower hardness than the end members 11.

[0014] In this embodiment, the fire spread prevention member 10 has a rectangular parallelepiped shape and is disposed so that the longest side of the rectangular parallelepiped corresponds to the height of the battery cell 20. The fire spread prevention member 10 includes end members 11 located at both ends in the longitudinal direction of the rectangular parallelepiped, and an inner member 12 located in an inner region between the both ends and having a lower hardness than the end members 11.

[0015] In this application, the "length direction" means the direction of the longest side of the rectangular parallelepiped when the shape of the target member is a rectangular parallelepiped, and means the direction of any one of the three sides that constitute the cube when the shape of the target member is a cube. Also, the "length direction" means the long axis direction of the widest surface of the elliptical plate when the shape of the target member is a thin elliptical plate, and means any diameter direction of the widest surface of the circular plate when the shape of the target member is a thin circular plate.

[0016] In the present application, the hardness (or hardness) of the rubber-like fire spread prevention member 10 refers to the Asker C hardness based on JIS K 7312. However, the hardness (or hardness) of the rubber-like fire spread prevention member 10 may be measured by another measurement method, for example, a rubber hardness test based on JIS K 6253, as long as the measurement method at each location of the fire spread prevention member 10 is standardized.

[0017] The hardness of each of the end member 11 and the inner member 12 is not particularly limited, so long as the hardness of the inner member 12 is lower than the hardness of the end member 11. As an example of a preferred hardness range, the hardness of the end member 11 is 45 to 60 on the Asker C scale, and the hardness of the inner member 12 is 20 to 40 on the Asker C scale.

[0018] Examples of rubber that mainly constitutes the fire spread prevention member 10 include thermosetting elastomers such as silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, nitrile rubber (NBR), and styrene butadiene rubber (SBR); thermoplastic elastomers such as urethane-based, ester-based, styrene-based, olefin-based, butadiene-based, and fluorine-based elastomers, and composites thereof. Among these rubbers, silicone rubber, which has relatively high heat resistance, can be used more preferably.

[0019] It is preferable that the fire spread prevention member 10 contains a flame retardant material to further improve the fire spread prevention performance. The flame retardant material is preferably one or more inorganic compounds such as carbon (including amorphous carbon and graphite), ceramics (mica, alumina, etc.), halides, phosphorus compounds, platinum, platinum complexes, magnesium hydroxide, and aluminum hydroxide. The content of the flame retardant material is preferably 0.5 to 20 mass %, more preferably 1 to 20 mass %, based on the total mass of the fire spread prevention member 10.

[0020] Of the end member 11 and the inner member 12, at least the inner member 12 may be a porous body. In this embodiment, both the end member 11 and the inner member 12 are porous bodies. Preferably, the end member 11 is made of silicone rubber (referred to as a first silicone rubber), and the inner member 12 is made of a silicone rubber (referred to as a second silicone rubber) having a lower hardness than the first silicone rubber. Preferably, of the first and second silicone rubbers, at least the second silicone rubber is a porous sponge-like silicone rubber. In this embodiment, both the end member 11 and the inner member 12 are sponge-like silicone rubber. Air bubbles in the rubber contribute to improving heat insulation. The end member 11 may be made non-porous, and the inner member 12 may be made porous. The volume of holes per unit volume of the end member 11 (porosity) may be smaller than the porosity of the inner member 12, so that the hardness of the end member 11 is greater than that of the inner member 12. The porosity of each of the end member 11 and the inner member 12 is preferably 40 to 95% by volume, and more preferably 60 to 90% by volume.

[0021] The size of the fire spread prevention member 10 can be changed in various ways depending on the size of the battery cell 20. Examples of the size of the fire spread prevention member 10 include a length of 200 mm or more and 300 mm or less, a width of 100 mm or more and 150 mm or less, and a thickness of 1 mm or more and 8 mm or less.

[0022] The length of the end member 11 in one direction is preferably 5% to 25% and more preferably 10% to 20% of the distance (=length) in the longitudinal direction of the fire spread prevention member 10. Therefore, the length of the inner member 12 is preferably 50% to 90% and more preferably 60% to 80% of the length of the fire spread prevention member 10 in the longitudinal direction.

[0023] Fig. 2 is a partially transparent perspective view showing a state in which a plurality of battery cells are set in a battery housing with the fire spread prevention member of Fig. 1 sandwiched between the battery cells. Fig. 3 is a vertical cross-sectional view showing a state in which a plurality of battery cells are set in the battery housing.

[0024] The battery 30 according to this embodiment is, for example, a battery for an electric vehicle, and includes a plurality of battery cells 20 arranged in a row. The number of battery cells 20 is 12 in this embodiment, but may be 2 to 11 or 13 or more. The battery 30 is a storage battery, and is preferably a lithium-ion battery. The battery 30 includes a bottomed housing 31 that is open on one side. The battery cells 20 are disposed inside 34 of the housing 31. The plurality of battery cells 20 are preferably in close contact with each other within the housing 31 by applying a compressive force from both sides of the housing 31 using a screw or the like (not shown).

[0025] The bottom 32 of the housing 31 is provided with one or more water-cooling pipes 33 for flowing cooling water, which is an example of a coolant 35. The coolant 35 may be called a cooling medium or a coolant. The battery cells 20 are arranged in the housing 31 with the fire spread prevention member 10 sandwiched between adjacent battery cells 20. The fire spread prevention member 10 and the battery cells 20 are loaded toward the inside 34 of the housing 31, as shown by the black arrow in FIG. 2. The fire spread prevention member 10 is not limited to being arranged between the battery cells 20, and may be arranged between the wall of the housing 31 and the battery cells 20.

[0026] Thus, the battery 30 according to one embodiment is a battery equipped with the above-mentioned fire spread prevention member 10, and has a structure in which the fire spread prevention member 10 is sandwiched between at least a plurality of battery cells 20 inside the battery 30.

[0027] FIG. 4 is a schematic diagram showing an enlarged cross-sectional view of a state in which a battery cell in the battery of FIG. 2 overheats and expands.

[0028] 4, the battery cell 20 tends to expand by curving so that the middle part of the long side of the widest surface, i.e., the long side of the widest surface, protrudes outward. In this case, the inner member 12 of the fire-spreading expansion member 10 is easily deformed so as to be recessed inward from the end member 11 because the inner member 12 has a lower hardness than the end member 11. The fire-spreading prevention member 10 can achieve both high strength due to the higher hardness of the end member 11 and high flexibility due to the lower hardness of the inner member 12.

[0029] FIG. 5 shows a perspective view (5A) of a first modified example in which the fire spread prevention member and battery cell orientation are different from those in FIG. 1, and a perspective view (5B) of a fire spread prevention member according to a second modified example having a different configuration from that of the fire spread prevention member in FIG.

[0030] (Variation 1) The battery cell 20 is not limited to being long in the height direction of the battery 30, and may be long in any direction, front-rear or left-right, of the battery 23. In this case, the fire spread prevention member 10 can also be formed to be long in the length direction of the battery cell 20. In the example shown in FIG. 5 (5A), the battery cell 20 is long in the front-rear direction of the battery 30. Here, the fire spread prevention member 10 is a member that is arranged so that the longest side of the rectangular parallelepiped corresponds to the width of the battery cell 20. For this reason, the fire spread prevention member 10 is long in the length direction (front-rear direction) of the battery cell 20, and is provided with end members 11 at both ends in the length direction, and is provided with an inner member 12 in the area sandwiched between the end members 11.

[0031] (Variation 2) The fire spread prevention member 10 may have a configuration other than the configuration in which the end member 11, the inner member 12, and the end member 11 are arranged in a straight line as shown in Fig. 1. That is, as in the fire spread prevention member 10 shown in Fig. 5 (5B), the end member 11 may extend to both sides in the width direction, which is the second longest direction after the length direction of the fire spread prevention member 10, and be formed on the inner and outer periphery of the surface of the fire spread prevention member 10, and the inner member 12 may be formed inside the inner and outer periphery of the surface.

[0032] 2. Manufacturing method of fire prevention components

[0033] FIG. 6 shows a flow of main manufacturing steps of a manufacturing method for a fire spread prevention member according to one embodiment.

[0034] A method for manufacturing a fire spread prevention member according to one embodiment is a method for manufacturing any of the fire spread prevention members 10 described above, and includes a first blending step (S100) of blending raw materials for end members 11 located at both ends in the length direction of the fire spread prevention member 10, a first sheeting step (S150) of forming the end members into a sheet after the first blending step, a second blending step (S200) of blending raw materials for an inner member 12 located in an inner region sandwiched between the both ends and having a lower hardness than the end members 11, a second sheeting step (S250) of forming the end members into a sheet after the second blending step, a joining step (S300) of joining the sheet after the first sheeting step and the sheet after the second sheeting step, and a vulcanization step (S400, S500) of vulcanizing and hardening the sheet after the joining step. Each step will be described in more detail below, taking the fire spread prevention member 10 made of sponge-like silicone rubber as an example.

[0035] (1) First blending process (S100) This step is a step of blending the raw materials of the end member 11. For example, when the end member 11 is a first silicone rubber, this step is a step of preparing a curable silicone rubber composition that is the raw material of the first silicone rubber. This step is preferably a step of mixing and kneading various materials. The curable silicone rubber composition contains known raw materials such as a silicone rubber base agent, typified by organopolysiloxane, a crosslinking agent (also called a vulcanizing agent), a catalyst, and a filler. When the end member 11 is a sponge-like silicone rubber, preferably, a foaming agent is contained in the curable silicone rubber composition. Examples of the foaming agent include organic foaming agents, typified by azobisisobutyronitrile (AIBN) or azodicarbonamide (ADCA). As an example of a method that does not contain an organic foaming agent, a method of preparing a curable silicone rubber composition to which thermally expandable resin beads are added can be mentioned. In this case, the resin beads become balloon-like during curing, and a sponge-like cured body can be obtained. As another example of a method that does not contain an organic foaming agent, a method of mixing air under high pressure into a non-foaming liquid silicone rubber composition can be mentioned. In this case, a sponge-like cured product can be obtained by curing the curable silicone rubber composition under normal pressure.

[0036] (2) First sheeting process (S150) This step is a step of forming a sheet using the raw material after the first blending step. The method of forming the sheet in this step is not particularly limited. For example, the mixed contents are placed in a mold and pressurized to form the sheet.

[0037] (3) Second blending process (S200) This step is a step of blending the raw materials of the inner member 12. For example, when the inner member 12 is a second silicone rubber, this step is a step of preparing a curable silicone rubber composition that is a raw material of the second silicone rubber. This step is preferably a step of mixing and kneading various materials. The curable silicone rubber composition contains known raw materials such as a silicone rubber base agent represented by organopolysiloxane, a crosslinking agent (also called a vulcanizing agent), a catalyst, and a filler. When the inner member 12 is a sponge-like silicone rubber, it is preferable to include a foaming agent similar to that in the first blending step. The inner member 12 has a lower rubber hardness than the end member 11. For this reason, it is preferable to change the curable silicone rubber composition for the inner member 12 from the curable silicone rubber composition for the end member 11. For example, a method can be exemplified in which the content of inorganic filler in the curable silicone rubber composition for the inner member 12 is made lower than the content of inorganic filler in the curable silicone rubber composition for the end member 11. As another example, the foaming agent content in the curable silicone rubber composition for the inner member 12 can be made higher than the foaming agent content in the curable silicone rubber composition for the end member 11.

[0038] (4) Second sheeting process (S250) This step is a step of forming a sheet using the raw material after the second blending step. The method of forming the sheet in this step is not particularly limited. For example, the mixed contents are placed in a mold and pressurized to form the sheet.

[0039] (5)Joining process (S300) This step is a step of bonding a sheet molded product that has been through the first sheeting step and a sheet molded product that has been through the second sheeting step to obtain one sheet molded product. Specifically, a method of placing a sheet molded product that has been through the second sheeting step inside a sheet molded product that has been through the first sheeting step, applying a load in the thickness direction of the sheet, and molding in a mold can be mentioned.

[0040] (6) Primary vulcanization process (S400) This step is a part of the vulcanization step, and is a step of heating and curing the bonded sheets. In this step, foaming occurs in the bonded sheets. The preferred temperature is 170 to 200°C.

[0041] (7) Secondary vulcanization process (S500) This step is a part of the vulcanization step, and is a step in which the sheet is further heated after the primary vulcanization to complete curing. In this step, the final thickness of the sheet is determined. The preferred temperature is 190 to 210°C. The vulcanization step may be a one-step step or a three or more-step step instead of the two-step step described above. EXAMPLES

[0042] Next, examples of the present invention will be described. Note that the present invention is not limited to the following examples.

[0043] 1. Manufacturing conditions Example 1 A mixture for sheet molding was prepared by mixing and kneading 100 parts by mass of silicone compound (product number: KE-561-U) manufactured by Shin-Etsu Chemical Co., Ltd., 0.3 parts by mass of vulcanizing agent (product number: C-1A) manufactured by Shin-Etsu Chemical Co., Ltd., 2.3 parts by mass of vulcanizing agent (product number: C-3) manufactured by Shin-Etsu Chemical Co., Ltd., 1.0 parts by mass of organic foaming agent "azobis-isobutyronitrile", and 1.0 parts by mass of black pigment (product number: KE-COLOR-CB) manufactured by Shin-Etsu Chemical Co., Ltd. The black pigment was added to make the end member black so that it would be easy to distinguish it from the inner member when photographing the fire spread prevention member. Next, the mixture after kneading was passed through two rolls with a gap adjusted to 1.5 mm after kneading and rolled into a sheet. This molding was performed twice to prepare two sheets for the end member. These are called "sheets for end members". Here, 1 part by mass is 10 g, and the same applies to Comparative Examples 1 and 2 described below.

[0044] Next, 100 parts by mass of silicone compound (product number: KE-541-U) manufactured by Shin-Etsu Chemical Co., Ltd., 0.3 parts by mass of vulcanizing agent (product number: C-1A) manufactured by Shin-Etsu Chemical Co., Ltd., 2.3 parts by mass of vulcanizing agent (product number: C-3) manufactured by Shin-Etsu Chemical Co., Ltd., and 1.0 part by mass of organic foaming agent "azobis-isobutyronitrile" were mixed and kneaded to prepare a compound for sheet molding. Next, the compound after kneading was passed through two rolls adjusted to a gap of 1.5 mm and rolled into a sheet. Such molding was performed once to prepare one sheet for the inner member. This is referred to as "sheet for inner member".

[0045] Next, the end member sheet was placed between two rolls with a gap adjusted to 1.5 mm so that it was sandwiched from both sides of the inner member sheet, and rolled (in practice, the sheets were rolled with the boundaries between them overlapping by about 1 mm), thereby joining the inner member sheet and the end member sheet.

[0046] Next, the bonded sheets were hung in a room at 190°C for 5 minutes to perform primary vulcanization. During this vulcanization, the bonded sheets were foamed and became thicker than before vulcanization. Next, the sheets after primary vulcanization were left to stand in a room at 200°C for 4 hours to perform secondary vulcanization.

[0047] Comparative Example 1 100 parts by mass of silicone compound (product number: KE-541-U) manufactured by Shin-Etsu Chemical Co., Ltd., 0.3 parts by mass of vulcanizing agent (product number: C-1A) manufactured by Shin-Etsu Chemical Co., Ltd., 2.3 parts by mass of vulcanizing agent (product number: C-3) manufactured by Shin-Etsu Chemical Co., Ltd., and 1.0 part by mass of organic foaming agent "azobis-isobutyronitrile" were mixed and kneaded to prepare a compound for sheet molding. Next, the compound after kneading was passed through two rolls adjusted to a gap of 1.5 mm and rolled to form a sheet. As a result, a sheet of the same size as the sheet after bonding in Example 1 was obtained. The conditions of the primary vulcanization and secondary vulcanization performed thereafter were the same as those in Example 1.

[0048] Comparative Example 2 A fire spread prevention member was produced under the same conditions as in Comparative Example 1, except that the silicone compound (product number: KE-541-U) was changed to a silicone compound (product number: KE-561-U).

[0049] 2. Evaluation method Each sample of the examples and comparative examples was subjected to evaluation of the compression load at which the thickness was reduced to 50% and the Asker C hardness, in addition to observing the appearance. The evaluation of the compression load was performed using an AG-20kN manufactured by Shimadzu Corporation. The compression load was the load when a sample piece of φ30 mm was extracted and compressed at a speed of 10 mm / min.

[0050] FIG. 7 shows the morphology and evaluation results of each sample of the examples and comparative examples.

[0051] The final thickness of each sample of Example 1 and Comparative Examples 1 and 2 was 3.9 mm±0.2. A load was applied in the thickness direction (Z direction) and the load at which the thickness was reduced to 50% was measured, with the results shown in FIG. 7 being obtained. That is, in the sample of Example 1, the load was 0.26 N / mm in the central low hardness region. 2 The load was 0.44N / mm in the high hardness area on the left side. 2 The load is 0.42N / mm in the high hardness region on the right side. 2 On the other hand, in the sample of Comparative Example 1, the load was 0.25 N / mm in all low hardness regions at the center, left end, and right end. 2 In the sample of Comparative Example 2, the load was 0.59 N / mm 2 The load is 0.56N / mm in the high hardness region on the left side. 2 The load is 0.55N / mm in the high hardness region on the right side. 2 In the sample of Comparative Example 2, although some load variations were observed, the load was 0.55 to 0.59 N / mm in the center, left end, and right end regions. 2 In this way, it was experimentally confirmed that in a structure in which a low hardness sheet is sandwiched between high hardness sheets, such as the sample of Example 1, the load at the center is low and the load at both the left and right ends is high. [Industrial Applicability]

[0052] The present invention can be used in batteries, for example automobile batteries. [Explanation of symbols]

[0053] 10...Fire prevention member, 11...end member, 12...inner member, 20...battery cell, 30...battery.

Claims

1. A rubber-like fire prevention member that is disposed between a plurality of battery cells inside a battery and that is capable of preventing the spread of fire by suppressing heat transfer to other battery cells when the battery cell is in an overheated state, end members located at both ends in the longitudinal direction of the fire spread prevention member; an inner member located in an inner region between the both ends and having a lower hardness than the end members; A fire spread prevention member comprising:

2. The fire spread prevention member has a rectangular parallelepiped shape, The fire spread prevention member is a member arranged such that the longest side of the rectangular parallelepiped corresponds to a height or width of the battery cell, end members located at both ends in the longitudinal direction of the rectangular parallelepiped; an inner member located in an inner region between the both ends and having a lower hardness than the end members; The fire spread prevention member according to claim 1 .

3. The end members extend to both sides in the width direction, which is the second longest after the length direction of the fire spread prevention member, and are formed on the inner and outer periphery parts of the surface of the fire spread prevention member, The fire spread prevention member according to claim 1 , wherein the inner member is formed on the inside of the inner and outer periphery of the surface.

4. 2. The fire spread prevention member according to claim 1, wherein at least the inner member out of the end members and the inner member is a porous body.

5. the end member is a first silicone rubber, 2. The fire spread prevention member according to claim 1, wherein the inner member is made of a second silicone rubber having a lower hardness than the first silicone rubber.

6. 6. The fire spread prevention member according to claim 5, wherein of the first silicone rubber and the second silicone rubber, at least the second silicone rubber is a porous sponge-like silicone rubber.

7. A method for producing the fire spread prevention member according to any one of claims 1 to 6, comprising the steps of: A first blending step of blending raw materials for end members located at both ends in the longitudinal direction of the fire spread prevention member; a first sheeting step of forming the mixture into a sheet after the first blending step; a second blending step of blending raw materials for an inner member located in an inner region between the both ends and having a lower hardness than the end members; A second sheeting step of forming the mixture into a sheet after the second blending step; a joining step of joining the sheet after the first sheeting step and the sheet after the second sheeting step; a vulcanization step of vulcanizing and hardening the sheet after the joining step; A method for producing a fire spread prevention member, comprising:

8. A battery comprising the fire spread prevention member according to any one of claims 1 to 6, A battery having a structure in which the fire spread prevention member is sandwiched between at least a plurality of battery cells within the battery.

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