Isolation sheet, battery pack, power supply device and mobile body

Abstract

To improve a battery temperature management function.SOLUTION: An isolation sheet 20 has a first surface 20a and a second surface 20b opposite to the first surface 20a. The isolation sheet 20 includes a surface layer 30 forming at least one of the first surface 20a and the second surface 20b, and a heat-resistant layer 40 and a foam layer 50 superimposed on the surface layer 30. The heat-resistant layer 40 has heat resistance. The foam layer 50 includes a porous portion 50p having a porous structure PS in the isolation sheet 20 in an overheated state. The surface layer 30 has a thermal conductivity of 0.50 W / (m.K) or more in a thickness direction DD of the isolation sheet 20.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an isolation sheet, a battery pack, a power supply device, and a mobile object. [Background technology]

[0002] As described in Patent Document 1, a power supply device that supplies electric power is known. The power supply device includes a plurality of batteries arranged in an arrangement direction and an isolation sheet disposed between two adjacent batteries in the arrangement direction. The batteries function as chargeable and dischargeable secondary batteries. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 131837 Summary of the Invention [Problem to be solved by the invention]

[0004] Batteries generate heat during charging and discharging. In order to suppress the temperature rise of the battery, it is necessary to release heat from the generating battery. In contrast, in a battery that has abnormally generated heat due to a short circuit, it is necessary to suppress the transfer of heat in order to suppress the temperature rise of other adjacent batteries. It is not easy to adjust the heat flow according to the battery state and manage the battery temperature. The present disclosure aims to improve the temperature management function of the battery. [Means for solving the problem]

[0005] The separator sheet according to one embodiment of the present disclosure comprises: a separator sheet having a first side and a second side opposite the first side, a surface layer forming at least one of the first surface and the second surface; A heat-resistant layer and a foam layer are laminated on the surface layer, The heat-resistant layer has heat resistance, The foam layer includes a porous portion having a porous structure in the heat shield sheet in an overheated state, The surface layer has a thermal conductivity of 0.50 W / (m·K) or more in the thickness direction of the isolation sheet. Effect of the Invention

[0006] According to the present disclosure, the temperature management function of a battery can be improved. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram for explaining one embodiment, and is an exploded perspective view of a power supply device. [Diagram 2] FIG. 2 is a cross-sectional view showing the first battery, the second battery, and the separator sheet included in the power supply device of FIG. [Diagram 3] FIG. 3 is a plan view of a foam layer included in the isolation sheet of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing the porous structure of the foam layer. [Diagram 5] FIG. 5 is a cross-sectional view showing a modified example of the isolation sheet. [Figure 6] FIG. 6 is a plan view showing a modified example of the foam layer. [Figure 7] FIG. 7 is a top view showing a modified example of the battery pack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] One embodiment of the present disclosure relates to the following [1] to

[17] .

[0009] [1] A separator sheet having a first surface and a second surface opposite the first surface, a surface layer forming at least one of the first surface and the second surface; A heat-resistant layer and a foam layer are laminated on the surface layer, The heat-resistant layer has heat resistance, the foam layer includes a porous forming portion having a porous structure in the isolation sheet in an overheated state, The surface layer has a thermal conductivity of 0.50 W / (m·K) or more in a thickness direction of the isolation sheet.

[0010] [2] The isolation sheet according to [1], wherein the thermal conductivity of the heat-resistant layer is lower than the thermal conductivity of the surface layer.

[0011] [3] The foam layer includes a first foam layer and a second foam layer, The isolation sheet of [1] or [2], wherein the first foam layer, the heat-resistant layer, and the second foam layer are located in this order from the first surface to the second surface.

[0012] [4] The heat-resistant layer includes a first heat-resistant layer and a second heat-resistant layer, The isolation sheet according to any one of [1] to [3], wherein the first heat-resistant layer, the foam layer, and the second heat-resistant layer are located in this order from the first surface to the second surface.

[0013] [5] The isolation sheet according to any one of [1] to [4], wherein the surface layer includes a first surface layer forming the first surface and a second surface layer forming the second surface.

[0014] [6] The isolation sheet according to any one of [1] to [5], wherein the layer constituting the first surface and the layer constituting the second surface have insulating properties.

[0015] [7] The isolation sheet according to any one of [1] to [6], wherein the surface layer contains at least one of an inorganic oxide and an inorganic nitride.

[0016] [8] The isolation sheet according to any one of [1] to [7], wherein the heat-resistant layer has flexibility.

[0017] [9] The isolation sheet according to any one of [1] to [8], wherein the foam layer is in a sheet form when the porous forming portion does not have the porous structure.

[0018]

[10] The foam layer has the porous portion and a support portion adjacent to the porous portion and supporting the porous portion, The isolation sheet according to any one of [1] to [9], wherein the Shore A hardness of the supporting portion is greater than the Shore A hardness of the porous portion.

[0019]

[11] The porous forming portion includes a base layer and a bonding layer overlaid on the base layer, The isolation sheet according to any one of [1] to

[10] , wherein at least one of the base layer and the bonding layer has the porous structure in the overheated state.

[0020]

[12] The isolation sheet of

[11] , wherein the bonding layers are laminated on both sides of the base layer.

[0021]

[13] The isolating sheet of any of [1] to

[12] , wherein the thickness of the foam layer in the isolating sheet in the overheated state is at least twice the thickness of the foam layer in the isolating sheet that is not yet overheated.

[0022]

[14] A battery or batteries; and an isolation sheet according to any one of [1] to

[13] disposed between the batteries.

[0023]

[15] A plurality of batteries arranged in an array direction; [5] an isolation sheet disposed between the plurality of batteries; The separator sheet contacts a battery located on a first side in the arrangement direction relative to the separator sheet through the first surface layer, and contacts a battery located on a second side opposite the first side in the arrangement direction relative to the separator sheet through the second surface layer.

[0024]

[16] A power supply comprising a battery pack as described in

[14] or

[15] .

[0025]

[17]

[16] A mobile object equipped with a power supply unit.

[0026] Hereinafter, an embodiment will be described with reference to the drawings. In the drawings, the scale and dimensional ratios are appropriately exaggerated from those of the actual objects for the convenience of illustration and ease of understanding.

[0027] Terms such as "orthogonal" and "identical" for specifying shapes, geometric conditions, and the degree thereof are not limited to the strict meanings. These terms are to be interpreted to include the range of the degree to which similar functions can be expected.

[0028] Directions common to the drawings are indicated by arrows with the same reference numerals in each drawing. In each direction, the tip of the arrow is the first side. In each direction, the side opposite to the first side, i.e., the base of the arrow, is the second side. An arrow pointing from the front to the back of the paper in a direction perpendicular to the paper surface is indicated by a symbol with an X in a circle, as shown in FIG. 2, for example. An arrow pointing from the back to the front of the paper in a direction perpendicular to the paper surface is indicated by a symbol with a dot in a circle, as shown in FIG. 7, for example.

[0029] 1 to 4 are diagrams illustrating one embodiment. Fig. 1 is an exploded perspective view of a power supply device 10. The power supply device 10 includes a housing 11 and a battery pack 16 housed in the housing 11. The battery pack 16 includes a plurality of batteries 15 arranged in an arrangement direction DA, and an isolation sheet 20 disposed between adjacent batteries 15. In the illustrated example, the batteries 15 are chargeable and dischargeable secondary batteries.

[0030] The power supply device 10 supplies electric power. The power supply device 10 may be applied to a mobile body that requires electric power. The mobile body is a movable device or equipment. The mobile body may be an automobile such as a passenger car, a bus, a truck, or a fire engine. The automobile may include a drive device such as an electric motor as a power source. The power supply device 10 may be attached to the automobile. In the automobile, the power supply device 10 supplies electric power for driving the drive device. The power supply device 10 supplies electric power by discharging a battery 15. The power supply device 10 may be supplied with electric power from an external source. The battery 15 may be charged by the electric power supplied from an external source.

[0031] In the example shown in FIG. 1, the housing 11 includes a bottom 12 and a plurality of side portions 13 extending from the bottom 12. The bottom 12 and the side portions 13 form a storage space for the battery pack 16. In the illustrated example, the bottom 12 has a longitudinal direction in a first direction D1 parallel to the arrangement direction DA of the batteries 15. The bottom 12 has a width direction in a second direction D2 perpendicular to the first direction D1. The side portions 13 extend from the bottom 12 in a direction non-parallel to the arrangement direction DA of the batteries 15. The side portions 13 extend in a third direction D3 perpendicular to both the first direction D1 and the second direction D2. The illustrated housing 11 is open in the third direction D3. The battery pack 16 may be housed in the housing 11 from the open portion of the housing 11. The battery pack 16 housed in the housing 11 may contact the side portions 13 of the housing 11 from the batteries 15 in the arrangement direction DA. The battery pack 16 housed in the housing 11 may come into contact with the side portion 13 of the housing 11 from the isolation sheet 20 in the arrangement direction DA.

[0032] The first direction D1, the second direction D2, and the third direction D3 are also used below to explain the battery pack 16 housed in the housing 11, and the batteries 15 and the isolation sheet 20 included in the battery pack 16.

[0033] In the battery pack 16 shown in FIG. 1, the batteries 15 and the isolating sheets 20 are alternately arranged in the arrangement direction DA. In the illustrated example, the arrangement direction DA is parallel to the first direction D1. The isolating sheet 20 faces the batteries 15 on at least one of the first surface 20a and the second surface 20b that face each other in the arrangement direction DA. The batteries 15 include facing portions 15s that face the first surface 20a or the second surface 20b of the isolating sheet 20. In the illustrated example, the first surface 20a and the second surface 20b face the arrangement direction DA. The facing portions 15s of the batteries 15 extend in a plane perpendicular to the arrangement direction DA.

[0034] 1, each battery 15 includes a pair of protruding electrode members 17. One electrode member 17 serves as the anode of each battery 15. The other electrode member 17 serves as the cathode of each battery 15. A battery 15 may be electrically connected to other batteries 15 at the electrode members 17. Batteries 15 adjacent to each other in the arrangement direction DA may be electrically connected to each other at the electrode members 17 by connecting means such as a conductor wire.

[0035] However, a battery has an optimum temperature range for stable charging and discharging. The battery generates heat when it is charged and discharged. If the battery is charged and discharged at a temperature higher than the optimum temperature range due to the heat generated, the battery may deteriorate rapidly. In order to suppress the rapid deterioration of the battery, it is preferable to release heat from the heated battery and suppress the temperature rise of the battery. In the illustrated battery pack 16, the release of heat from the battery 15 is promoted by the isolation sheet 20, as described later. The upper limit of the optimum temperature range of the illustrated battery 15 may be 35°C or 30°C on the surface of the battery 15.

[0036] The surface temperature of the battery 15 that has generated heat due to charging and discharging may be 40° C. or higher, or 50° C. or higher. The surface temperature of the battery 15 that has generated heat due to charging and discharging may be less than 70° C. or less than 60° C. The heated battery 15 may be cooled to the above-mentioned optimum temperature range by promoting heat release.

[0037] Batteries may expand due to repeated charging and discharging. In the illustrated power supply device 10, the batteries 15 may expand in the arrangement direction DA. In the illustrated power supply device 10, the expansion of the batteries 15 in the arrangement direction DA may cause the isolation sheet 20 to be compressed in the thickness direction DD of the isolation sheet 20.

[0038] Furthermore, a battery may short-circuit and generate abnormal heat due to various factors such as an external impact, a foreign object in the battery, or metal crystal growth in the battery. A battery that generates abnormal heat cannot function as a secondary battery. In other words, a battery that generates abnormal heat cannot be charged or discharged. In a battery pack, the heat from a battery that generates abnormal heat may be transmitted to other batteries adjacent to the battery that generates abnormal heat in a chain reaction. If multiple batteries generate abnormal heat in a chain reaction, the entire battery pack may generate abnormal heat. If the abnormal heat generation in the battery progresses further, the battery and the battery pack may ignite.

[0039] In the power supply device 10 and battery pack 16 shown in Fig. 1, abnormal heat generation in a certain battery 15 can cause the isolating sheet 20 in contact with that battery 15 to become overheated. The heat from the abnormally heated battery 15 can be transferred through the isolating sheet 20 to other batteries 15 adjacent to that battery 15 in the arrangement direction DA. This can lead to a chain reaction of the other batteries 15 also abnormally heating up. Repeated heat transfer to adjacent batteries 15 in the arrangement direction DA can cause the entire battery pack 16 to abnormally heat up.

[0040] The "overheated state" of the isolating sheet 20 means a state in which the surface temperature of at least one of the first surface 20a and the second surface 20b of the isolating sheet 20 is 100° C. or higher. The "unheated state" of the isolating sheet 20 means a state in which the surface temperature of the isolating sheet 20 on the first surface 20a and the surface temperature of the isolating sheet 20 on the second surface 20b are both less than 100° C.

[0041] 2 shows a first battery 15A and a second battery 15B included in a battery pack 16, and an isolating sheet 20 arranged between these batteries 15. The first battery 15A is located on a first side in the arrangement direction DA from the isolating sheet 20. The second battery 15B is located on a second side in the arrangement direction DA from the isolating sheet 20. The isolating sheet 20 is in contact with the first battery 15A from a first surface 20a. The isolating sheet 20 is in contact with the second battery 15B from a second surface 20b.

[0042] In the example shown in Fig. 2, the isolation sheet 20 is a sheet having a certain thickness. The illustrated isolation sheet 20 is flat. The isolation sheet 20 has a thickness direction DD parallel to the arrangement direction DA of the batteries 15. The isolation sheet 20 may have a thickness of 0.50 mm or more. The isolation sheet 20 may have a thickness of 3.0 mm or less.

[0043] In the example shown in FIG. 2, the isolating sheet 20 includes a surface layer 30, and a heat-resistant layer 40 and a foam layer 50 that are superposed on the surface layer 30 in the thickness direction DD. That is, the thickness direction DD is the lamination direction of the isolating sheet 20. The surface layer 30 may include a first surface layer 31 and a second surface layer 32 that are spaced apart from each other in the thickness direction DD. The heat-resistant layer 40 may include a first heat-resistant layer 41 and a second heat-resistant layer 42 that are spaced apart from each other in the thickness direction DD. The foam layer 50 may include a first foam layer 51 and a second foam layer 52 that are spaced apart from each other in the thickness direction DD. In the illustrated isolating sheet 20, the first surface layer 31, the first heat-resistant layer 41, the foam layer 50, the second heat-resistant layer 42, and the second surface layer 32 are located in this order from the first surface 20a to the second surface 20b.

[0044] 2, the isolation sheet 20 contacts the first battery 15A from the first surface layer 31. The isolation sheet 20 contacts the second battery 15B from the second surface layer 32.

[0045] The layer constituting the first surface 20a and the layer constituting the second surface 20b of the isolating sheet 20 may each have insulating properties. In the illustrated example, the first surface layer 31 and the second surface layer 32 each have insulating properties. The first surface layer 31 and the second surface layer 32 may have insulating properties, thereby insulating the battery 15 and the isolating sheet 20. This can suppress unintended short circuits in the battery 15.

[0046] The component of the isolation sheet 20 has insulating properties when the component is 7This means that the component has a sheet resistance of ohms / square or more. A resistivity meter (Hiresta-UX MCP-HT800) capable of measuring in accordance with JIS K 6911:1995 is used to measure the sheet resistance. When measuring the sheet resistance, a probe electrically connected to the resistivity meter is pressed against the component.

[0047] The surface layer 30 forms either the first surface 20a or the second surface 20b of the isolation sheet 20. At least one of the first surface 20a or the first surface 20a of the isolation sheet 20 contacts the battery 15 from the surface layer 30. In the illustrated example, the first surface layer 31 forms the first surface 20a of the isolation sheet 20. The second surface layer 32 forms the second surface 20b of the isolation sheet 20. The isolation sheet 20 contacts the first battery 15A from the first surface layer 31. The isolation sheet 20 contacts the second battery 15B from the second surface layer 32. The first surface layer 31 and the second surface layer 32 may have the same configuration as each other. The first surface layer 31 and the second surface layer 32 may have different configurations from each other.

[0048] In the example shown in FIG. 2, the surface layer 30 has thermal conductivity. The constituent elements of the isolation sheet 20 "have thermal conductivity" means that the thermal conductivity of the constituent elements in the thickness direction DD is 0.50 W / (m·K) or more. The surface layer 30 may have a thermal conductivity of 1.0 W / (m·K) or more. The thermal conductivity of the constituent elements of the isolation sheet 20 is calculated by multiplying the thermal diffusivity measured by the laser flash method using a thermal property measuring device (LFA-502 manufactured by Kyoto Electronics Manufacturing Co., Ltd.) conforming to JIS R 1611:1997 and JIS H 7801:2005, by the density and specific heat of the constituent elements. The specific heat is measured by laser flash differential calorimetry using the above-mentioned thermal property measuring device (LFA-502 manufactured by Kyoto Electronics Manufacturing Co., Ltd.). The density is measured using a measuring device (Ultrapyc 5000 manufactured by Anton Paar) capable of performing measurements using the gas displacement method specified in JIS Z 8807:2012. The thermal conductivity of the components of the isolation sheet 20 is calculated using the average values ​​of five values ​​measured by the above-mentioned method for five different samples for the thermal diffusivity, specific heat, and density. The thermal diffusivity is measured using a sample having a size of 10 mm square.

[0049] The surface layer 30 promotes heat transfer in the battery 15. The surface layer 30 may promote heat transfer in a direction non-parallel to the arrangement direction DA of the battery 15. In the example shown in FIG. 2, heat HT of a certain portion of the first battery 15A is diffused in the third direction D3 through the first surface layer 31. The heat HT of a certain portion of the first battery 15A may be diffused in the second direction D2 through the first surface layer 31. In FIG. 2, the diffusing heat is indicated by an arrow HF. The certain portion of the first battery 15A may be cooled by the heat moving through the first surface layer 31.

[0050] The surface layer 30 may include an inorganic oxide such as zirconia, silica, aluminum oxide (alumina), zinc oxide, magnesium oxide (magnesia), beryllium oxide (beryllia), etc. The surface layer 30 may include an inorganic nitride such as silicon nitride, boron nitride, aluminum nitride, etc. The surface layer 30 may include one or more of an inorganic oxide and an inorganic nitride.

[0051] 2, the heat-resistant layer 40 includes a first heat-resistant layer 41 and a second heat-resistant layer 42 spaced apart from each other in the thickness direction DD. The first heat-resistant layer 41 and the second heat-resistant layer 42 may have the same configuration as each other.

[0052] The heat-resistant layer 40 has heat resistance. The presence or absence of heat resistance is determined by placing the isolating sheet 20 including the heat-resistant layer 40 in a 300° C. oven and heating it for 5 minutes. The heat-resistant layer 40 "has heat resistance" means that the average thickness of the heat-resistant layer 40 in the cross section of the isolating sheet 20 after heating is 95% or more and less than 105% of the average thickness of the heat-resistant layer 40 in the cross section of the isolating sheet 20 before heating. The average thickness of the heat-resistant layer 40 in the isolating sheet 20 is the average value of five measured values ​​of the thickness of the heat-resistant layer 40 obtained by measuring five different cross sections of the isolating sheet 20. The thickness of the heat-resistant layer 40 is determined by a laser microscope (LEXT (registered trademark) OLS5100 manufactured by Olympus Corporation). The heat-resistant layer 40 can suppress deformation and melting of the isolating sheet 20 in an overheated state.

[0053] The heat-resistant layer 40 may include inorganic fibers such as glass fibers and carbon fibers. The heat-resistant layer 40 may include organic fibers such as aramid fibers. The heat-resistant layer 40 may include a filler such as talc, sepiolite, mica, etc. In the heat-resistant layer 40, the filler may be filled into the inorganic fibers or organic fibers.

[0054] The heat-resistant layer 40 may be flexible. The heat-resistant layer 40 being "flexible" means that the heat-resistant layer 40 does not crack or break when the heat-resistant layer 40 is wound around a roll having a diameter of 50 mm.

[0055] As shown in FIG. 2, the isolation sheet 20 may include an auxiliary bonding layer 60 that bonds the surface layer 30 and the heat-resistant layer 40. In the illustrated example, the auxiliary bonding layer 60 includes a first auxiliary bonding layer 61 located between the first surface layer 31 and the first heat-resistant layer 41, and a second auxiliary bonding layer 62 located between the second surface layer 32 and the second heat-resistant layer 42. The auxiliary bonding layer 60 may include an adhesive or a pressure-sensitive adhesive. The adhesive included in the auxiliary bonding layer 60 may include one or more of an acrylic adhesive, a rubber adhesive, a urethane adhesive, and a silicone adhesive. The pressure-sensitive adhesive included in the auxiliary bonding layer 60 may include one or more of an acrylic adhesive, a rubber adhesive, a urethane adhesive, and a silicone adhesive.

[0056] The foam layer 50 includes a porous formation portion 50p having a porous structure PS in the isolating sheet 20 in an overheated state. The porous formation portion 50p "has a porous structure PS in the isolating sheet 20 in an overheated state" means that the porous formation portion 50p can have the porous structure PS in the isolating sheet 20 maintained in an overheated state for 5 minutes. However, if the temperature of the foam layer 50 in the isolating sheet 20 in an overheated state is too high, the foam layer 50 may burn, and the porous structure PS formed in the porous formation portion 50p may not remain. The porous formation portion 50p has the porous structure PS in the isolating sheet 20 in an overheated state in which the surface temperature of at least one of the first surface 20a and the second surface 20b is maintained in the range of 100°C to 300°C for 5 minutes.

[0057] The porous portion 50p "has a porous structure PS" means that, when a cross section of the porous portion 50p is observed, 10 or more bubbles having a maximum length of 50 μm or more are observed in a 1.0 mm square area. The number of bubbles observed is calculated as the average of five counts obtained by observing five different fields of view.

[0058] The porous formation portion 50p may have the porous structure PS not only in an overheated isolation sheet 20 but also in an isolation sheet 20 that is not yet overheated. The porous formation portion 50p may have the porous structure PS during the manufacturing stage of the isolation sheet 20.

[0059] In the porous portion 50p, the porous structure PS formed in the isolation sheet 20 in an overheated state may be maintained even in the isolation sheet 20 whose temperature has been reduced, for example, in the isolation sheet 20 that has returned to a non-overheated state.

[0060] In the example shown in Fig. 2 and Fig. 3, the foam layer 50 is in a sheet shape when it does not have a porous structure PS. In producing the isolation sheet 20, the sheet-shaped foam layer 50 may be attached to the surface layer 30 or the heat-resistant layer 40. The foam layer 50 has a thickness direction parallel to the thickness direction DD of the isolation sheet 20. The foam layer 50 may have a thickness of 300 µm or more when it does not have a porous structure PS. The foam layer 50 may have a thickness of 1 mm or less when it does not have a porous structure PS.

[0061] The porous portion 50p "does not have a porous structure PS" means that, when observing a cross section of the porous portion 50p, less than 10 bubbles having a maximum length of 50 μm or more are observed in an area of ​​1.0 mm square. The number of bubbles observed is calculated as the average of five counts obtained by observing five different fields of view.

[0062] 2 and 3, the foam layer 50 includes a porous portion 50p and a support portion 50s adjacent to the porous portion 50p. In FIG. 3, four porous portions 50p spaced apart from each other in a direction non-parallel to the thickness direction of the foam layer 50 are surrounded by the support portion 50s.

[0063] 2, the porous forming portion 50p includes a base layer 56 and a bonding layer 57 laminated on the base layer 56. In the illustrated example, the porous forming portion 50p includes a pair of bonding layers 57 laminated on both sides of the base layer 56.

[0064] The base layer 56 maintains the shape of the foam layer 50 in the porous forming portion 50p. The base layer 56 supports the bonding layer 57. The base layer 56 may be in a sheet shape. The base layer 56 may include a thermoplastic resin. The thermoplastic resin included in the base layer 56 may include one or more of PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PEI (polyetherimide), PVAL (polyvinyl alcohol), PVCD (polyvinylidene chloride), nylon 6, and nylon 66. The base layer 56 may include a resin that crosslinks by electron beam irradiation. The base layer 56 may include polypropylene that crosslinks by electron beam irradiation. The base layer 56 may include polyethylene that crosslinks by electron beam irradiation. The base layer 56 may include rubber.

[0065] When the base layer 56 includes a foaming agent PA, described below, the above-mentioned materials of the base layer 56 may function as a binder BD.

[0066] The bonding layer 57 improves the adhesion between the foam layer 50 and the layers of the isolation sheet 20 other than the foam layer 50. The bonding layer 57 may include an adhesive or a pressure-sensitive adhesive. The adhesive contained in the bonding layer 57 may include one or more of an acrylic adhesive, a rubber adhesive, a urethane adhesive, and a silicone adhesive. The adhesive contained in the bonding layer 57 may include one or more of an acrylic adhesive, a rubber adhesive, a urethane adhesive, and a silicone adhesive. When the bonding layer 57 includes a foaming agent PA described below, the above-mentioned material of the bonding layer 57 may function as a binder BD.

[0067] In the example shown in FIG. 2, the porous forming portion 50p contains a foaming agent PA. The foaming agent PA foams when heated. The foaming agent PA may form bubbles in the isolation sheet 20 in an overheated state. The porous forming portion 50p contains the foaming agent PA to form a porous structure PS in the isolation sheet 20 in an overheated state. In the porous forming portion 50p, the base layer 56 may contain the foaming agent PA. In the illustrated porous forming portion 50p, the bonding layer 57 may contain the foaming agent PA. In the porous forming portion 50p, both the base layer 56 and the bonding layer 57 may contain the foaming agent PA. In the illustrated porous forming portion 50p, the base layer 56 has the foaming agent PA.

[0068] The foaming agent PA may be a physical foaming agent that vaporizes when heated to form bubbles. The heated physical foaming agent may vaporize in the isolation sheet 20 that is not yet in an overheated state. The heated physical foaming agent may vaporize in the isolation sheet 20 that is in an overheated state. The boiling point of the physical foaming agent under atmospheric pressure may be 80°C or higher, 100°C or higher, 130°C or higher, or 150°C or higher. The physical foaming agent may be a hydrocarbon such as cyclohexane or n-heptane. The physical foaming agent may be a halogenated hydrocarbon such as dichloroethane. The physical foaming agent may be a fluorocarbon such as a hydrofluorocarbon (HFC).

[0069] The foaming agent PA may be a chemical foaming agent that forms bubbles by thermal decomposition or reaction when heated. In the isolation sheet 20 that is not yet in an overheated state, the heated chemical foaming agent may start to thermally decompose or react. In the isolation sheet 20 that is in an overheated state, the heated chemical foaming agent may start to thermally decompose or react. The temperature at which the chemical foaming agent starts to thermally decompose or react may be 80°C or higher, 100°C or higher, 130°C or higher, or 150°C or higher. The chemical foaming agent may generate gases such as nitrogen gas, carbon dioxide gas, oxygen gas, ammonia gas, hydrogen gas, carbon monoxide, and water vapor by decomposition or reaction. These gases may form bubbles. The chemical foaming agent may be an organic foaming agent such as dinitrosopentamethylenetetramine (DPT), azodicarbonamide (ADCA), 4,4'-oxybisbenzenesulfonylhydrazide, an isocyanate compound, or the like. The chemical foaming agent may be an inorganic foaming agent such as baking soda.

[0070] Due to the foaming of the foaming agent PA, the porous forming portion 50p has a porous structure PS in the isolation sheet 20 in an overheated state, as shown in FIG. 4. The illustrated porous structure PS includes a plurality of air bubbles BB. The plurality of air bubbles BB are dispersed in the binder BD. The plurality of air bubbles BB dispersed in the binder BD may be located apart from each other as shown in FIG. 4. In the porous structure PS, the plurality of air bubbles BB may be connected to each other.

[0071] The thickness of the porous forming portion 50p in the isolation sheet 20 in the overheated state may increase due to foaming of the foaming agent PA. The thickness of the porous forming portion 50p in the isolation sheet 20 in the overheated state may be more than twice as thick as the porous forming portion 50p in the isolation sheet 20 that is not yet overheated. When comparing the thicknesses of the porous forming portion 50p, these thicknesses are measured in a state where the foam layer 50 is not superimposed on other layers of the isolation sheet 20.

[0072] In the example shown in Fig. 2 and Fig. 3, the support portion 50s surrounds the porous portion 50p. The support portion 50s supports the porous portion 50p. The support portion 50s may support the porous portion 50p in the isolation sheet 20 that is not yet in an overheated state. The support portion 50s may be referred to as a support portion. By supporting the porous portion 50p, compression of the porous portion 50p due to expansion of the battery 15 may be suppressed.

[0073] 3, the thickness of the support portion 50s is greater than the thickness of the porous portion 50p when the foam layer 50 is not superimposed on another layer of the isolation sheet 20. The support portion 50s may be compressed when the foam layer 50 is superimposed on another layer of the isolation sheet 20.

[0074] The support portion 50s may include rubber such as urethane rubber, silicone rubber, etc. The support portion 50s may include foaming resin such as urethane foam.

[0075] The Shore A hardness of the support portion 50s may be greater than the Shore A hardness of the porous portion 50p. The Shore A hardness of the porous portion 50p and the support portion 50s is determined as follows using a type A durometer conforming to JIS K 6253-3:2023. The pressure plate of the type A durometer is brought into contact with the porous portion 50p or the support portion 50s, and the value after 15 seconds is obtained as the measured value. The Shore A hardness of the porous portion 50p and the support portion 50s is measured in accordance with JIS K 6253-3:2023 under conditions other than those mentioned above. The Shore A hardness of the porous portion 50p is determined as the average value of the measured values ​​obtained at five different points on the porous portion 50p. Similarly, the Shore A hardness of the support portion 50s is determined as the average value of the measured values ​​obtained at five different points on the support portion 50s.

[0076] The operation of the illustrated power supply device 10 will now be described.

[0077] When the power supply device 10 supplies power, the battery 15 included in the battery pack 16 discharges. When the power supply device 10 receives power, the battery 15 included in the battery pack 16 charges. The battery 15 generates heat during charging and discharging. Meanwhile, the isolation sheet 20 adjacent to the battery 15 in the arrangement direction DA includes a surface layer 30. According to this specific example, the heat of the battery 15 is released in a direction non-parallel to the arrangement direction DA by the surface layer 30, as already described with reference to FIG. 2. This makes it possible to suppress the temperature rise of the battery 15 due to charging and discharging in the illustrated power supply device 10. The power supply device 10 can charge and discharge the battery 15 within an appropriate temperature range. Therefore, rapid deterioration of the battery 15 is suppressed, and the power supply device 10 can stably supply power.

[0078] However, as described above, batteries may abnormally heat up due to various factors. In a battery pack including at least one abnormally heated battery, other batteries adjacent to the battery may abnormally heat up in a chain reaction, causing the entire battery pack to abnormally heat up. As the abnormal heat progresses, the battery pack may catch fire. It is necessary to secure time for people to move away from a power supply device including the ignited battery pack and a mobile object including such a power supply device. In the illustrated battery pack 16, when a certain battery 15 abnormally heats up, it is necessary to delay the temperature rise of other batteries 15 adjacent to the battery 15 in the arrangement direction DA.

[0079] In contrast, the illustrated isolating sheet 20 includes a foam layer 50. The foam layer 50 includes a porous forming portion 50p having a porous structure PS in the isolating sheet 20 in an overheated state as a porous forming portion 50p. The porous forming portion 50p forms the porous structure PS by foaming in the isolating sheet 20 in an overheated state. When the porous forming portion 50p includes a physical foaming agent, bubbles are generated by vaporizing the physical foaming agent in the isolating sheet 20 in an overheated state. When the porous forming portion 50p includes a chemical foaming agent, bubbles are generated by pyrolyzing the chemical foaming agent in the isolating sheet 20 in an overheated state or by reacting with the chemical foaming agent. The thermal conductivity of the foam layer 50 is significantly reduced in the porous forming portion 50p due to the bubbles contained in the porous structure PS. As a result, the illustrated isolating sheet 20 can suppress heat transfer between adjacent batteries 15 in the arrangement direction DA in an overheated state.

[0080] The illustrated isolating sheet 20 also includes a heat-resistant layer 40 having heat resistance. The heat-resistant layer 40 can suppress deformation and melting of the isolating sheet 20 in an overheated state. In the battery pack 16 including such an isolating sheet 20, it is possible to suppress the occurrence of a portion where the isolating sheet 20 is not disposed between adjacent batteries 15 in the arrangement direction DA, which would be caused by deformation or melting of the isolating sheet 20 in an overheated state. In other words, the isolating sheet 20 can more reliably dispose the foam layer 50 described above between adjacent batteries 15 in the arrangement direction DA even in an overheated state.

[0081] Therefore, in the illustrated assembled battery 16, the isolating sheet 20 including the heat-resistant layer 40 and the foam layer 50 is disposed between the multiple batteries 15, thereby preventing the heat from an abnormally heated battery 15 from transferring to other batteries 15 adjacent thereto in the arrangement direction DA. As a result, in a power supply device 10 including the assembled battery 16 and a mobile body including the power supply device 10, even if at least one battery 15 abnormally heats up, time can be secured for a person to move away from the power supply device 10 or the mobile body.

[0082] From the viewpoint of more effectively suppressing heat transfer in the arrangement direction DA in the battery pack 16, the heat-resistant layer 40 in the isolation sheet 20 may have a lower thermal conductivity than the surface layer 30. The thermal conductivity of the heat-resistant layer 40 may be 1.0 W / (m·K) or less, or may be 0.10 W / (m·K) or less.

[0083] In the illustrated isolating sheet 20, the surface layer 30 includes a first surface layer 31 forming the first surface 20a and a second surface layer 32 forming the second surface 20b. According to this specific example, the first surface layer 31 can suppress a temperature rise in the first battery 15A. Moreover, the second surface layer 32 can suppress a temperature rise in the second battery 15B. Therefore, a single isolating sheet 20 can efficiently suppress a temperature rise in two batteries 15 adjacent to each other in the arrangement direction DA.

[0084] In the illustrated isolating sheet 20, the layer constituting the first surface 20a and the layer constituting the second surface 20b are each insulating. In the illustrated example, the first surface layer 31 and the second surface layer 32 are insulating. According to this specific example, the battery 15 and the isolating sheet 20 are electrically insulated. This makes it possible to suppress the generation of unintended current in the area where the battery 15 and the isolating sheet 20 contact each other.

[0085] In the illustrated isolating sheet 20, the foam layer 50 is in a sheet-like form when the porous forming portion 50p does not have the porous structure PS. According to this specific example, the isolating sheet 20 can be easily produced by overlapping the sheet-like foam layer 50 on other layers of the isolating sheet 20.

[0086] In the illustrated isolation sheet 20, the foam layer 50 includes a porous portion 50p and a support portion 50s adjacent to the porous portion 50p. The porous portion 50p has a porous structure PS in an overheated state. The support portion 50s supports the porous portion 50p. The Shore A hardness of the support portion 50s is greater than the Shore A hardness of the porous portion 50p. According to this specific example, when the porous portion 50p and the support portion 50s are compressed with the same compressive force, the compression amount of the support portion 50s is smaller than the compression amount of the porous portion 50p. This allows the support portion 50s to suppress compression of the porous portion 50p caused by expansion of the battery 15 due to repeated charging and discharging. The thickness of the porous portion 50p can be ensured even in the isolation sheet 20 in an overheated state. Therefore, the porous portion 50p can stably suppress heat transfer in the arrangement direction DA in the isolation sheet 20 in an overheated state.

[0087] In the embodiment described above, the isolating sheet 20 has a first surface 20a and a second surface 20b opposite to the first surface 20a. The isolating sheet 20 includes a surface layer 30 forming at least one of the first surface 20a and the second surface 20b, and a heat-resistant layer 40 and a foam layer 50 superimposed on the surface layer 30. The heat-resistant layer 40 has heat resistance. The foam layer 50 includes a porous portion having a porous structure PS in the isolating sheet 20 in an overheated state. The surface layer 30 has a thermal conductivity of 1.0 W / (m·K) or more in the thickness direction DD of the isolating sheet 20.

[0088] According to this embodiment, heat from the battery 15 during charging and discharging is released from the battery 15 by the surface layer 30 of the isolating sheet 20. By suppressing the temperature rise of the battery 15, the assembled battery 16 and the power supply device 10 can stably supply power. On the other hand, when the battery 15 generates abnormal heat, the heat-resistant layer 40 and the foam layer 50 of the isolating sheet 20 can suppress the transfer of heat to other adjacent batteries 15 in the arrangement direction DA. Therefore, in the assembled battery 16 or the power supply device 10 including such an isolating sheet 20, the temperature management function of the battery 15 can be improved.

[0089] Although one embodiment has been described with reference to a specific example, the above-mentioned specific example does not limit the embodiment. The above-mentioned embodiment can be embodied in various other specific examples, and various omissions, substitutions, changes, additions, etc. can be made without departing from the spirit of the embodiment.

[0090] In one specific example of the isolating sheet 20 described above, the isolating sheet 20 included, as the surface layer 30, a first surface layer 31 and a second surface layer 32 spaced apart from each other in the thickness direction DD. The isolating sheet 20 included, as the heat-resistant layer 40, a first heat-resistant layer 41 and a second heat-resistant layer 42 spaced apart from each other in the thickness direction DD. The isolating sheet 20 included one foamed layer 50. The layer configuration of the isolating sheet 20 is not limited thereto, and may include, from the first surface 20a to the second surface 20b, the first surface layer 31, the first foamed layer 51, the heat-resistant layer 40, the second foamed layer 52, and the second surface layer 32 in this order, as shown in FIG. 5 .

[0091] In the example shown in Fig. 3, the foam layer 50 includes four porous forming parts 50p arranged in a direction non-parallel to the arrangement direction DA, and a support part 50s surrounding the porous forming parts 50p. The arrangement of the porous forming parts 50p and the support part 50s is not limited thereto, and for example, as shown in Fig. 6, the foam layer 50 may include one porous forming part 50p and a support part 50s surrounding the outer periphery of the porous forming part 50p.

[0092] In the battery pack 16 described above, the isolating sheet 20 is flat. The isolating sheet 20 may be arranged between the batteries 15 in a bent state, as shown in FIG. 7. The isolating sheet 20 may be bent according to the shape of the batteries 15. The isolating sheet 20 may be bent about a plurality of axes parallel to each other, as shown in FIG. 7. The isolating sheet 20 may be arranged between the batteries 15 in a serpentine state.

[0093] In the battery pack 16 described above, the isolating sheet 20 is disposed between two batteries 15 arranged in the arrangement direction DA. In the battery pack 16, the isolating sheet 20 does not have to be disposed between two batteries 15 adjacent to each other in the arrangement direction DA, as shown in FIG. 7. In the illustrated battery pack 16, the isolating sheet 20 is disposed between the first battery row 18A and the second battery row 18B. In each battery row 18A, 18B, a plurality of batteries 15 are arranged in the arrangement direction DA. Each battery 15 has a cylindrical shape. In the isolating sheet 20 thus disposed about an axis extending in the third direction D3, the surface layer 30 may promote heat transfer of the batteries 15. The surface layer 30 may promote heat transfer of the batteries 15 in the arrangement direction DA, not limited to a direction non-parallel to the arrangement direction DA. [Explanation of symbols]

[0094] 10: power supply device, 15: battery, 16: battery pack, 20: isolation sheet, 20a: first surface, 20b: second surface, 30: surface layer, 31: first surface layer, 32: second surface layer, 40: heat-resistant layer, 41: first heat-resistant layer, 42: second heat-resistant layer, 50: foam layer, 50p: porous portion, 50s: support portion, 51: first foam layer, 52: second foam layer, 56: base layer, 57: bonding layer, DA: arrangement direction, PS: porous structure

Claims

1. an isolation sheet having a first side and a second side opposite the first side, a surface layer forming at least one of the first surface and the second surface; A heat-resistant layer and a foam layer are laminated on the surface layer, The heat-resistant layer has heat resistance, the foam layer includes a porous forming portion having a porous structure in the isolation sheet in an overheated state, The surface layer has a thermal conductivity of 0.50 W / (m·K) or more in a thickness direction of the isolation sheet.

2. The isolation sheet of claim 1 , wherein the heat-resistant layer has a thermal conductivity lower than that of the surface layer.

3. The foam layer includes a first foam layer and a second foam layer, The isolation sheet according to claim 1 , wherein the first foam layer, the heat-resistant layer, and the second foam layer are positioned in this order from the first surface to the second surface.

4. the heat-resistant layer includes a first heat-resistant layer and a second heat-resistant layer, The isolation sheet according to claim 1 , wherein the first heat-resistant layer, the foam layer, and the second heat-resistant layer are located in this order from the first surface to the second surface.

5. The isolation sheet of claim 1 , wherein the surface layer includes a first surface layer forming the first side and a second surface layer forming the second side.

6. The isolation sheet according to claim 1 , wherein the layer constituting the first surface and the layer constituting the second surface are insulating.

7. The isolation sheet of claim 1 , wherein the surface layer comprises one or more of an inorganic oxide and an inorganic nitride.

8. The isolation sheet of claim 1 , wherein the heat-resistant layer is flexible.

9. The isolation sheet according to claim 1 , wherein the foam layer is in a sheet form when the porous forming portion does not have the porous structure.

10. The foam layer has the porous portion and a support portion adjacent to the porous portion and supporting the porous portion, The isolation sheet of claim 1 , wherein the Shore A hardness of the support portion is greater than the Shore A hardness of the porous forming portion.

11. The porous forming portion includes a base layer and a bonding layer overlaid on the base layer, The isolation sheet of claim 1 , wherein at least one of the base layer and the bonding layer has the porous structure in the overheated state.

12. The separator sheet of claim 11 , wherein the adhesive layer is overlaid on both sides of the base layer.

13. 2. The isolation sheet of claim 1, wherein the thickness of the foam layer in the overheated isolation sheet is at least twice as thick as the thickness of the foam layer in the isolation sheet that is not yet overheated.

14. A number of batteries; and the separator sheet according to any one of claims 1 to 13, disposed between the plurality of batteries.

15. A plurality of batteries arranged in an array direction; and the separator sheet of claim 5 disposed between the plurality of batteries. The isolation sheet contacts a battery located on a first side in the arrangement direction relative to the isolation sheet from the first surface layer, and contacts a battery located on a second side opposite the first side in the arrangement direction relative to the isolation sheet from the second surface layer.

16. A power supply device comprising the battery pack according to claim 14.

17. A mobile object comprising the power supply device according to claim 16.

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