Laminate and energy storage device

Abstract

The present invention provides a laminate with excellent heat insulation and cushioning properties, and an energy storage device equipped with the laminate. [Solution] The laminate of the present disclosure comprises a silicone foam layer and a thermal insulation layer laminated on the silicone foam layer, wherein the thermal insulation layer is an inorganic porous material.

Description

Technical Field

[0001] The present invention relates to a laminate and a power storage device.

Background Art

[0002] For batteries used in electric vehicles (EVs), a heat insulating material is used between cells to prevent the transfer of heat generated from cells during charging and discharging or during abnormal conditions such as thermal runaway. In addition to heat insulation, the heat insulating material requires cushioning properties that can withstand vibrations and impacts associated with shaking during vehicle travel.

[0003] Conventionally, an insulator (heat insulating material) between battery cells using an aerogel with excellent heat insulation has been disclosed (for example, Patent Document 1). In addition, a heat insulating material using a resin foam with excellent cushioning properties has been proposed (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the technology of Patent Document 1 has the problems that the aerogel is fragile, easily deteriorates due to external stresses such as thermal expansion of cells, and has poor cushioning properties. In addition, the technology of Patent Document 2 has the problem that the resin foam cannot withstand high temperatures (700 to 800°C) when the cell undergoes thermal runaway, catches fire or decomposes, and cannot maintain heat insulation properties.

[0006] The problem to be solved by the invention is to provide a laminate excellent in heat insulation and cushioning properties, and a power storage device including the laminate.

Means for Solving the Problems

[0007] One aspect of the present invention is a laminate. The laminate includes a silicone foam layer and a heat insulation layer laminated on the silicone foam layer, and the heat insulation layer is an inorganic porous body.

[0008] In the laminate of the above aspect, it is preferable that the heat insulation layer contains a geopolymer cured body.

[0009] In the laminate of the above aspect, it is preferable that the 5% compression strength is 0.15 MPa or more.

[0010] Another aspect of the present invention is a power storage device. The power storage device includes the laminate of the above aspect.

Advantages of the Invention

[0011] According to the present invention, it is possible to provide a laminate excellent in heat insulation and cushioning properties, and a power storage device including the laminate.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view schematically showing the laminate of the present embodiment.

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the disclosed technology will be described in detail. In this specification, the notation "a~b" in the description of a numerical range represents a to b unless otherwise specified.

[0014] In this specification, when a plurality of upper limit values and a plurality of lower limit values are separately described, all numerical ranges that can be freely combined and set by these upper limit values and lower limit values are described in this specification.

[0015] In this specification, density (apparent density) is the apparent density measured in accordance with JIS K7222:2005 "Foamed plastics and rubber - Method for determining apparent density".

[0016] In this specification, the average particle size is the value of the 50th percentile diameter (median particle size D50) of the volume-based integrated fraction in the particle size distribution measured by a laser diffraction particle size distribution analyzer.

[0017] In this specification, the weight-average molecular weight (number-average molecular weight) can be measured using known measurement methods, such as the polystyrene-based molecular weight, by gel permeation chromatography (GPC).

[0018] 1. Laminate 1-1.Shape The shape of the laminate in this embodiment is not particularly limited and can be any shape appropriate for the application. For example, the laminate can be in the shape of a sheet. By being in the shape of a sheet, the laminate can be suitably used as an insulating material between cells in an energy storage device described later.

[0019] 1-2. Thickness The thickness of the laminate in this embodiment is not particularly limited, but is preferably 1.0 mm or more, 2.0 mm or more, 3.0 mm or more, 4.0 mm or more, and also preferably 40.0 mm or less, 30.0 mm or less, 20.0 mm or less, 10.0 mm or less. By setting the thickness of the laminate within the above range, it can be suitably used as an insulating material between cells in the energy storage device described later.

[0020] 1-3. Structure Figure 1 is a schematic cross-sectional view illustrating the laminate 10 of this embodiment. As shown in Figure 1, the laminate 10 comprises a silicone foam layer 11 and a heat insulating layer 12. The heat insulating layer 12 is laminated on the silicone foam layer 11.

[0021] The thermal insulation layer 12 is preferably laminated directly onto the silicone foam layer 11. Furthermore, the laminate 10 of this embodiment may have any other layers as long as it includes the silicone foam layer 11 and the thermal insulation layer 12. For example, another layer may be interposed between the silicone foam layer 11 and the thermal insulation layer 12. The other layer is not particularly limited and could be, for example, an adhesive layer that joins the silicone foam layer 11 and the thermal insulation layer 12.

[0022] Figure 1 shows an example where the laminate 10 has a two-layer structure of silicone foam layer 11 / insulation layer 12, with one silicone foam layer 11 and one insulation layer 12 laminated together. However, this embodiment is not limited to this. In other words, in this embodiment, the laminate 10 may have two or more layers of either the silicone foam layer 11 or the insulation layer 12, or both.

[0023] For example, the laminate 10 can have a three-layer structure such as silicone foam layer 11 / insulation layer 12 / silicone foam layer 11, insulation layer 12 / silicone foam layer 11 / insulation layer 12, or a four-layer structure such as silicone foam layer 11 / insulation layer 12 / silicone foam layer 11 / insulation layer 12.

[0024] Among the above, the three-layer structure of silicone foam layer 11 / insulation layer 12 / silicone foam layer 11 provides superior cushioning of the laminate 10 compared to the two-layer structure, making it suitable for use as insulation between cells in energy storage devices.

[0025] The silicone foam layer 11 and the heat insulating layer 12 that constitute the laminate 10 will be described in detail below.

[0026] 1-3-1. Silicone foam layer 11 (Material / Type) The silicone resin forming the silicone foam layer 11 is a resin having organopolysiloxane as its main chain, and is not particularly limited.

[0027] The type of the silicone foam layer 11 is not particularly limited. For example, it may be a silicone foam of a solid raw material type (such as a millable silicone foam) or a silicone foam of a liquid raw material type (such as a two-component silicone foam).

[0028] The millable silicone foam is a silicone foam obtained by kneading organopolysiloxane as a main raw material and blending various additives (filler, dispersant, vulcanizing agent, etc.) and then thermally curing it. By using a foaming agent (chemical foaming agent) as an additive, a foamed silicone resin can be obtained.

[0029] The two-component silicone foam is a foam in which gas (hydrogen) generated during curing causes foaming by mixing and stirring two liquid silicone materials, and cells are formed.

[0030] The silicone foam layer 11 is preferably a two-component silicone foam.

[0031] (Thickness) The thickness of the silicone foam layer 11 is not particularly limited. For example, 0.5 mm or more, 1.0 mm or more, 1.5 mm or more, 2.0 mm or more, etc. are preferable, and 20.0 mm or less, 15.0 mm or less, 10.0 mm or less, 5.0 mm or less, etc. are also preferable. By setting the thickness of the silicone foam layer 11 within the above range, the cushioning property of the laminate 10 can be further improved.

[0032] (Density) The density of the silicone foam layer 11 is not particularly limited. For example, 100 kg / m 3 or more, 125 kg / m 3 or more, 150 kg / m 3 or more, 175 kg / m 3 or more, 200 kg / m 3 or more, etc. are preferable, and 900 kg / m 3 or less, 800 kg / m 3 or less, 700 kg / m 3 or less, 600 kg / m 3 or less, 500 kg / m3 Below 400kg / m 3 Below 300kg / m 3 The following are preferred.

[0033] (Hardness) The hardness {25%CLD(kPa)} of the silicone foam layer 11 is preferably, for example, 1,000kPa or less, 500kPa or less, 300kPa or less, 250kPa or less, 200kPa or less, 150kPa or less, 100kPa or less, etc.

[0034] The hardness {25%CLD(kPa)} of the silicone foam layer 11 can be adjusted by changing the material of the silicone foam, the cell diameter and density of the silicone foam, etc.

[0035] 1-3-2. Insulation layer 12 (Structure / Material) The thermal insulation layer 12 in this embodiment is an inorganic porous material. By making the thermal insulation layer 12 an inorganic porous material, the thermal insulation performance can be further improved. The size of the pores in the inorganic porous material is not particularly limited and may be, for example, microporous, mesoporous, macroporous, etc.

[0036] The pores of the inorganic porous material may be either closed cells or interconnected pores, but closed cells are preferable. By making the pores of the inorganic porous material closed cells, the permeability is reduced compared to having interconnected pores, which tends to result in superior thermal insulation of the insulation layer 12.

[0037] The inorganic porous material is not particularly limited and includes, for example, inorganic fibrous substrates formed by fibers (e.g., woven fabrics and nonwoven fabrics), and inorganic substrates in which pores have been formed.

[0038] The inorganic fiber base material may be either a woven fabric or a nonwoven fabric. As the fibers constituting the inorganic fiber base material, for example, metal fibers composed of metals such as stainless steel, aluminum, and copper, or inorganic fibers composed of inorganic materials such as glass, carbon, silica, rock wool, zirconia, and alumina can be used. Among the above, the inorganic fiber base material is preferably a nonwoven fabric composed of glass fibers.

[0039] As the inorganic substrate, a porous substrate mainly composed of inorganic materials such as silica, alumina, ceramics, and geopolymers can be used. In particular, from the viewpoint of balancing the thermal insulation properties, processability, and ease of manufacture of the thermal insulation layer 12, it is preferable to include silica and geopolymer. Furthermore, from the viewpoint of further enhancing the thermal insulation properties of the thermal insulation layer 12, it is even more preferable to include a geopolymer cured body formed from the geopolymer.

[0040] The geopolymers that form the geopolymer cured bodies are amorphous polymers made primarily from materials such as aluminum and silicon, and are obtained by the reaction of aluminosilicates and activators, as described later.

[0041] The inorganic porous material described above preferably contains an aerogel and an infrared-absorbing filler, as needed. It may also contain a filler. Including an aerogel and an infrared-absorbing filler in the inorganic porous material can further improve the thermal insulation properties of the thermal insulation layer 12. Furthermore, including a filler in the inorganic porous material can further improve the strength of the thermal insulation layer 12.

[0042] (thickness) The thickness of the thermal insulation layer 12 can be appropriately changed depending on the application and is not particularly limited. For example, 0.5 mm or more, 1.0 mm or more, 1.5 mm or more, 2.0 mm or more are preferred, and 20.0 mm or less, 15.0 mm or less, 10.0 mm or less, 5.0 mm or less are also preferred. By setting the thickness of the thermal insulation layer 12 within the above range, the thermal insulation performance, processability, ease of manufacture, etc. of the thermal insulation layer 12 can be improved in a well-balanced manner. Furthermore, it can be suitably used as thermal insulation material between cells in energy storage devices, as described later.

[0043] (Apparent density) The density of the thermal insulation layer 12 in this embodiment is 100 kg / m³. 3 More than 200kg / m 3 More than 300kg / m 3 Preferably, the above, and 1,060 kg / m³. 3 Below 800kg / m 3 Below 600kg / m 3 Below 500kg / m 3 The following are preferable. If the apparent density is within the above range, the laminate 10 can be made lighter. In addition, it becomes easier to incorporate air into the interior of the insulation layer 12, so the insulation performance can be further improved.

[0044] (Thermal conductivity) The thermal conductivity in the thickness direction of the insulating layer 12 in this embodiment is preferably 50 mW / m·K or less, 45 mW / m·K or less, 40 mW / m·K, 35 mW / m·K, etc. as an upper limit. The lower limit is not particularly limited, but is preferably 5 mW / m·K or more. Here, the thermal conductivity was measured using a thermal conductivity measuring device (HC-72, manufactured by Eiko Seiki Co., Ltd.) in accordance with JIS A1412-2:1999 "Method for measuring thermal resistance and thermal conductivity of thermal insulating materials - Part 2: Heat flow meter method (HFM method)". If the thermal conductivity of the insulating layer 12 is within the above range, sufficient thermal insulation can be achieved even if the laminate 10 is formed in a sheet shape.

[0045] (Compressive strength) In this embodiment, the heat insulating layer 12 preferably has a 5% compressive strength of 0.1 MPa or higher, 0.15 MPa or higher, 0.3 MPa or higher, 0.35 MPa or higher, etc., as measured in a compression test (see the examples described later for details). If the compressive strength is within the above range, sufficient strength can be obtained even if the laminate 10 is formed in a sheet shape.

[0046] (Thermal insulation) In this embodiment, the surface temperature of the insulating layer 12 measured in an insulating test (see the examples described later for details) is preferably 310°C or lower, 300°C or lower, 290°C or lower, 280°C or lower, 270°C or lower, 260°C or lower, 250°C or lower, 230°C or lower, etc. The insulating properties of the insulating layer 12 in this embodiment can be evaluated by the insulating test.

[0047] 2. Method for manufacturing laminates The manufacturing method for the laminate 10 of this embodiment includes a silicone foam layer formation step, a heat insulating layer formation step, and a lamination step of laminating the silicone foam layer and the heat insulating layer. The order in which the silicone foam layer formation step and the heat insulating layer formation step are performed is not particularly limited, and either step may be performed first.

[0048] 2-1. Silicone foam layer formation process In this embodiment, commercially available silicone foam may be used as the silicone foam layer 11. Therefore, the silicone foam layer formation step is not necessarily required and may be omitted when using commercially available silicone foam.

[0049] In this embodiment, the silicone foam layer 11 is described as an example in which the two-component silicone foam described above is used. However, this embodiment is not limited to this.

[0050] If the silicone foam layer 11 is a two-component silicone foam, the two-component liquid silicone is mixed and stirred to carry out the foaming and curing reaction. Specifically, a self-foaming silicone foam can be obtained by foaming (due to the generated hydrogen gas) and curing through the following reaction carried out in the presence of a catalyst such as a platinum catalyst.

[0051] Reaction 1: Reaction of a silanol group-containing organopolysiloxane or hydroxyl group-containing compound (foaming agent), such as hydroxyl-terminated polydimethylsiloxane, with an organohydrogenpolysiloxane, such as methylhydrogenpolysiloxane, which has SiH groups at both ends and in the side chain. Reaction 2: Reaction of a vinyl group-containing organopolysiloxane, such as dimethylpolysiloxane, which has both ends sealed with dimethylvinylsiloxy groups, with an organohydrogenpolysiloxane, such as methylhydrogenpolysiloxane, which has SiH groups at both ends and in the side chains.

[0052] Furthermore, when mixing and stirring the two-part liquid silicone raw materials, an inert gas such as air or nitrogen may be added. This allows for the formation of more uniform cells, as the inert gas acts as a foaming nucleus.

[0053] Specific examples of platinum catalysts include chloroplatinic acid, elemental platinum, chloroplatinic acid hexahydrate, chloroplatinic acid complexes with sym-divinyltetramethyldisiloxane, dichloro-bis(triphenylphosphine)platinum(II), cis-dichlorobis(acetonitrile)platinum(II), dicarbonyldichloroplatinum(II), platinum chloride, platinum oxide, zero-valent platinum metal complexes, e.g., Karstedt catalyst, [Cp*Ru(MeCN)3]PF6, [PtCl2(cyclooctadiene)], solid platinum supported on a carrier (e.g., alumina, silica, or carbon black), platinum-vinylsiloxane complexes {e.g., Ptn(ViMe2SiOSiMe2Vi)c and Pt[(MeViSiO)4]}. dExamples include platinum-phosphine complexes {e.g., Pt(PPh3)4 and Pt(PBU3)4} and platinum-phosphite complexes {e.g., Pt[P(Oph)3]4 and Pt[P(Obu)3]4}. Here, in the above formulas, "Me" represents methyl, "Bu" represents butyl, "Vi" represents vinyl, and "Ph" represents phenyl, and c and d represent integers.

[0054] As the hydroxyl group-containing compound (foaming aid), alcohols such as benzyl alcohol and ethanol, and water can be used. In this case, a stock solution containing vinyl group-containing organopolysiloxane (main polymer), hydroxyl group-containing compound (foaming aid), and catalyst may be prepared as solution A, and a stock solution containing vinyl group-containing organopolysiloxane (main polymer) and organohydrogenpolysiloxane (crosslinking agent) may be prepared as solution B. The foaming reaction and curing reaction may be carried out by mixing and stirring solutions A and B. The number average molecular weight of the main polymer is preferably 500 to 100,000, more preferably 1,000 to 70,000, and even more preferably 1,500 to 50,000. When using two solutions consisting of solution A and solution B as described above, the mixing ratio (mass ratio) of solution A and solution B depends on the density and cell morphology of the silicone foam layer 11 to be obtained, but is typically 100:1 to 100:50. Furthermore, the above-mentioned filler is preferably added to solution A.

[0055] The reaction time during hydrogen generation is appropriately adjusted depending on the density and cell morphology of the silicone foam layer 11 to be obtained. It is typically 1 to 10 minutes, preferably 2 to 6 minutes. The mixing temperature is appropriately adjusted depending on the density and cell morphology of the silicone foam layer 11 to be obtained. It is typically room temperature.

[0056] Furthermore, the density of the silicone foam layer 11 can be adjusted by optimizing the temperature during curing and foaming (molding), the amount of foaming aid, and the ratio of liquid A to liquid B (amount of Si-H added).

[0057] 2-2. Insulation layer formation process In this embodiment, commercially available inorganic porous materials (inorganic fiber substrates, inorganic substrates, etc.) may be used for the thermal insulation layer 12. Therefore, the thermal insulation layer formation step is not necessarily required, and may be omitted if commercially available inorganic porous materials are used for the thermal insulation layer 12.

[0058] In this embodiment, the process of forming the heat insulating layer will be described using the case in which the heat insulating layer 12, among the inorganic porous materials described above, includes a geopolymer cured material as an example. However, this embodiment is not limited to this.

[0059] A geopolymer cured body can be obtained by curing a geopolymer manufacturing composition.

[0060] The thermal insulation layer formation process includes a preparation step for preparing the geopolymer manufacturing composition and a curing step for curing the geopolymer manufacturing composition. Each step will be described below.

[0061] 2-2-1. Adjustment Steps In the preparation step, the geopolymer manufacturing composition is prepared. The geopolymer manufacturing composition comprises an aluminosilicate, an aerogel, an acidic activator, and water. Preferably, the geopolymer manufacturing composition further contains fillers other than the aerogel.

[0062] In this embodiment, an example is shown in which an acidic activator is used as an activator for the geopolymer manufacturing composition. However, a geopolymer cured product, as described later, can also be obtained by using an alkaline activator. By using an acidic activator, a geopolymer cured product with superior mechanical properties and heat resistance can be obtained.

[0063] The following details each component that makes up the geopolymer manufacturing composition.

[0064] (Aluminosilicate) The aluminosilicate of this embodiment (xM2O·yAl2O3·zSiO2·nH2O, where M is an alkali metal) is a compound having a structure in which some of the silicon atoms in the silicate are replaced with aluminum atoms.

[0065] Examples of aluminosilicates used in this embodiment include one or more selected from natural aluminosilicate minerals such as illite, stilbite, kaolinite, pyrophyllite, andalusite, bentonite, kyanite, miranite, globenite, amesite, cordierite, feldspar, and allophane; calcined natural aluminosilicate minerals such as imogolite and metakaolin; fly ash obtained from the combustion of coal; and blast furnace slag obtained when iron ore is converted into cast iron in a blast furnace. Among these, calcined natural aluminosilicate minerals are preferred, and metakaolin is particularly preferred.

[0066] These substances can be commercially available, and one or more of them can be used in combination. Furthermore, aluminosilicates are used in powder or granular form, and can be adjusted to the desired particle size by grinding and classifying them as appropriate and using specific fractions.

[0067] A particularly preferred aluminosilicate in this embodiment is the compound represented by the chemical formula Al2O3·2SiO2. The content of metakaolin relative to the total mass of the aluminosilicate is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. When the content of metakaolin relative to the total mass of the aluminosilicate is within the above range, a geopolymer cured body with excellent strength can be stably obtained.

[0068] The aluminosilicate powder preferably has an average particle size of 0.1 to 50 μm, more preferably 0.3 to 30 μm, and even more preferably 0.5 to 10 μm or less. When the average particle size of the powder is within this range, the thermal insulation properties of the manufactured geopolymer cured body can be further improved.

[0069] The aluminosilicate content is preferably 1% by mass or more, 5% by mass or more, or 7% by mass or more, relative to the total mass of the geopolymer manufacturing composition, and preferably 60% by mass or less, 55% by mass or less, or 50% by mass or less, relative to the total mass of the geopolymer manufacturing composition. By setting the aluminosilicate content within the above range, it is easier to increase the strength of the cured geopolymer.

[0070] (Aerogel) Aerogels are not particularly limited and include, for example, low-density dry gels. Specific examples include aerogels obtained using supercritical fluid drying, xerogels obtained through conventional drying processes, and cryogels obtained through freeze-drying.

[0071] Any suitable aerogel component can be used as the aerogel. For example, inorganic aerogels such as silica aerogel and alumina aerogel, organic aerogels such as resorcinol-formaldehyde aerogel (RF aerogel) and cellulose nanofiber aerogel (CNF aerogel), carbon aerogel, and mixtures thereof can be selected. Among these, silica aerogel containing silica (SiO2) is preferred.

[0072] The average particle size of the aerogel is preferably 0.01 mm or larger, 0.02 mm or larger, 0.05 mm or larger, 0.08 mm or larger, and preferably 5.0 mm or smaller, 3.0 mm or smaller, 2.0 mm or smaller, 1.5 mm or smaller. By setting the average particle size of the aerogel within the above range, a geopolymer cured body with superior heat insulation properties can be obtained.

[0073] The pore size of the aerogel is preferably 30 nm or less, more preferably 25 nm or less, and even more preferably 20 nm or less. Here, "pore size" is the value measured using a pore distribution analyzer (e.g., BELSORP MINI manufactured by Microtrac-Bel) in accordance with JIS Z8831-2 "Pore size distribution and pore characteristics of powders (solids) - Part 2: Measurement method for mesopores and macropores by gas adsorption". When the pore size is within this range, a geopolymer cured body with superior thermal insulation properties can be obtained.

[0074] The porosity of the aerogel is preferably over 90%, 95% or more, or 96% or more. The upper limit is not particularly limited, but for example, 99% or less, 98% or less, or 97% or less are preferred. By setting the porosity of the aerogel within the above range, a geopolymer cured body with superior heat insulation properties can be obtained.

[0075] The density of aerogel is 50 kg / m³. 3 More than 60kg / m 3 More than 70kg / m 3 More than 80kg / m 3 More than 90kg / m 3 More than 100kg / m 3 More than 110kg / m 3 The above are preferable, and also 275 kg / m 3 Below 250kg / m 3 Below 240kg / m 3 Below 230kg / m 3 Below 220kg / m 3 Below 210kg / m 3 Below 200kg / m 3 The following are preferred.

[0076] The bulk density of aerogel is 1 kg / m³. 3 More than 10kg / m 3 More than 20kg / m 3 More than 30kg / m 3 More than 40kg / m 3 More than 50kg / m 3 More than 60kg / m 3 The above are preferable, and also 175 kg / m 3Below 150kg / m 3 Below 140kg / m 3 Below 130kg / m 3 Below 120kg / m 3 Below 110kg / m 3 Below 100kg / m 3 The following are preferred.

[0077] Bulk density can be measured by the tapping method (ISO 787-11). Specifically, the bulk density is calculated from the volume obtained after placing the object in a 250 mL graduated cylinder and tapping it 1250 times.

[0078] The aerogel content is preferably more than 0% by mass, 3% or more by mass, 5% or more by mass, or 7% or more by mass, relative to the total mass of the geopolymer manufacturing composition, and preferably 30% or less by mass, 20% or less by mass, or 15% or less by mass, relative to the total mass of the geopolymer manufacturing composition. By setting the aerogel content within the above range, the thermal insulation properties of the cured geopolymer can be further improved.

[0079] (Infrared filler) The infrared absorbing filler is a component other than the aluminosilicate and aerogel mentioned above, and is a filler that has infrared absorbing properties. Preferably, the infrared absorbing filler is one or more selected from carbon-containing inorganic fillers, metal oxides, and metal inorganic salts. Including an infrared absorbing filler can further improve the thermal insulation properties of the geopolymer cured body described later.

[0080] Carbon-containing inorganic fillers are not particularly limited as long as they are carbon-derived fillers, and examples include carbon black, silicon carbide, boron carbide, carbon short fibers, graphene, graphene oxide, fullerene, carbon nanotubes, graphite, graphite oxide, and diamond.

[0081] The metal oxide is not particularly limited as long as it is a known metal oxide, and examples include titanium oxide, zinc oxide, iron oxide, magnesium oxide, aluminum oxide, spinel, zirconium oxide, cerium oxide, antimony oxide, tin oxide, lead oxide, chromium oxide, cobalt oxide, niobium oxide, nickel oxide, molybdenum oxide, tungsten oxide, palladium oxide, copper oxide, and the like.

[0082] Examples of inorganic metal salts include lithium carbonate, sodium carbonate, calcium carbonate, potassium carbonate, nickel carbonate, magnesium carbonate, lithium chloride, sodium chloride, potassium chloride, aluminum sulfate, calcium sulfate, aluminum chloride, aluminum nitrate, lithium nitrate, sodium nitrate, and potassium nitrate.

[0083] Among the infrared absorbing fillers mentioned above, it is particularly preferable that the infrared absorbing filler contains one or more selected from carbon black, silicon carbide, and titanium dioxide, and more preferably silicon carbide. Among the infrared absorbing fillers mentioned above, silicon carbide absorbs or reflects infrared rays and suppresses infrared transmission, thereby further improving the thermal insulation properties of the geopolymer cured body.

[0084] The shape of the infrared-absorbing filler is not particularly limited and may be spherical, amorphous, or flaky, with a spherical shape being preferred. By making the infrared-absorbing filler spherical, the fluidity of the geopolymer manufacturing composition after compounding can be increased. The structure of the infrared-absorbing filler is not particularly limited and may be solid or hollow. Hollow refers to a structure having a cavity inside surrounded by an outer shell. The internal cavity may be sealed, or a part of it may be in communication with the outside.

[0085] The average particle size of the infrared-absorbing filler is particularly preferably in the ranges of 0.05 to 50.0 μm, 0.05 to 25.0 μm, 0.05 to 10.0 μm, 0.05 to 5.0 μm, 0.10 to 5.0 μm, or 0.15 to 3.0 μm. By setting the average particle size of the infrared-absorbing filler within these ranges, the infrared-absorbing filler will have wavelengths in the high-temperature range of 500°C or higher. Therefore, wavelengths in the infrared region between 500°C and 1,500°C can be efficiently reflected by Mie scattering, thereby further improving the thermal insulation properties of the geopolymer cured body.

[0086] The bulk density of the infrared-absorbing filler is 0.001 to 1.000 g / cm³. 3 A range of 0.010 to 0.500 g / cm³ is preferred. 3 A range of 0.050 to 0.200 g / cm³ is more preferable. 3 A range of this magnitude is even more preferable. The method for measuring bulk density is the same as described above.

[0087] The content of the infrared absorbing filler is not particularly limited, but is preferably more than 0% by mass, 0.1% or more by mass, 0.2% or more by mass, 0.3% or more by mass, 0.5% or more by mass, 1% or more by mass, 3% or more by mass, 5% or more by mass, etc., relative to the total mass of the geopolymer manufacturing composition, and preferably 10% or less by mass, 9% or less by mass, 8% or less by mass, 7% or less by mass, 6% or less by mass, etc. By setting the content of the infrared absorbing filler within the above range, the thermal insulation properties of the cured geopolymer can be further improved.

[0088] (Acid activator) The acidic activator acts as a crosslinking agent when curing the geopolymer manufacturing composition. The acidic activator is not particularly limited, and known ones can be used. Examples include phosphate-based activators, nitrate-based activators, and sulfuric acid-based activators. In this embodiment, among these acidic activators, phosphate-based activators are preferred. In this embodiment, when a phosphate-based activator is used as the acidic activator, the geopolymer cured product described later will contain a structure derived from phosphate in the geopolymer skeleton. Below, an example of an acidic activator using a phosphate-based activator will be described.

[0089] Furthermore, even when using acidic activators other than phosphate-based activators, the content (amount added) and concentration of these activators can be appropriately adjusted by referring to the case where phosphate-based activators are used, so as to ensure that crosslinking by the activator proceeds sufficiently. For example, the content of the acidic activator relative to the total mass of the geopolymer manufacturing composition is preferably 1% by mass or more, 5% by mass or more, 8% by mass or more, and preferably 60% by mass or less, 55% by mass or less, 50% by mass or less.

[0090] The phosphate-based activator used as an acidic activator is not particularly limited. Examples of phosphate-based activators include mixtures such as aqueous solutions containing phosphoric acid (H3PO4), and phosphate ions (PO4 3- Examples include salts (phosphates) formed from ). Phosphates react with water to form phosphate ions (PO4 3- Any salt that releases ammonium dihydrogen phosphate (NH4H2PO4), sodium dihydrogen phosphate (NaH2PO4), potassium dihydrogen phosphate (KH2PO4), ammonium hydrogen phosphate ((NH4)2HPO4), sodium hydrogen phosphate (Na2HPO4), etc. are acceptable.

[0091] A suitable example of a phosphate-based activator is a high-concentration aqueous phosphoric acid solution. The phosphoric acid concentration of the high-concentration aqueous phosphoric acid solution is preferably 45% by mass or more, 50% by mass or more, 55% by mass or more, and preferably 95% by mass or less, 90% by mass or less, 85% by mass or less. By using a high-concentration aqueous phosphoric acid solution with the above phosphoric acid concentrations, crosslinking and kneading can be performed efficiently.

[0092] When preparing a geopolymer manufacturing composition, the ratio of the amount of high-concentration phosphoric acid aqueous solution added to the total mass of the geopolymer manufacturing composition is preferably 1% by mass or more, 3% by mass or more, 5% by mass or more, and preferably 30% by mass or less, 25% by mass or less, 20% by mass or less.

[0093] The phosphoric acid concentration relative to the total mass of the geopolymer manufacturing composition is preferably, for example, 0.4 to 29.0% by mass, more preferably 1.0 to 15.0% by mass, and even more preferably 3.0 to 10.0% by mass.

[0094] As long as the phosphoric acid concentration relative to the total mass of the geopolymer manufacturing composition is within the range described above, a high-concentration aqueous phosphoric acid solution or a phosphate salt may be used as the phosphoric acid activator. Furthermore, there are no particular restrictions on the order in which the components are mixed when preparing the geopolymer manufacturing composition.

[0095] Specifically, when using a high-concentration aqueous phosphoric acid solution as a phosphoric acid-based activator, the geopolymer manufacturing composition may be prepared by adding a mixture of the solid component and the water described later to the high-concentration aqueous phosphoric acid solution while stirring. Alternatively, when using a phosphate as an acidic activator, the geopolymer manufacturing composition may be prepared by adding water described later to a mixture of the phosphate and the solid component.

[0096] (water) The water may be deionized water, distilled water, or water containing up to 0.1% by mass of impurities, such as ordinary tap water.

[0097] The water content is not particularly limited, as long as the phosphoric acid concentration relative to the total mass of the geopolymer manufacturing composition is within the range described above, but it is preferably in the range of 5 to 50% by mass relative to the total mass of the geopolymer manufacturing composition.

[0098] (Filler) The filler is a component other than the aluminosilicate, aerogel, infrared-absorbing filler, acid activator, and water mentioned above, and preferably includes inorganic particles (inorganic filler). By using inorganic particles as the filler, the geopolymer cured body described later can be made less prone to combustion even in high-temperature environments.

[0099] Examples of inorganic particles include oxides such as silicon dioxide (silica), thorium silicate, boron silicate, and aluminosilicate; hydroxides such as sodium hydroxide, calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; and nitrides such as silicon nitride and boron nitride. One or more inorganic particles selected from the above-mentioned list may be used.

[0100] The filler preferably contains silicon dioxide (silica) among the inorganic particles mentioned above, and it is preferable that the silicon dioxide (silica) content is 90% by mass or more of the total mass of the filler. Silica is broadly divided into wet silica, which is mainly synthesized in a liquid, and dry silica, which is synthesized by hydrolysis at high temperatures. In this embodiment, either wet silica or dry silica may be used as the filler. By including silica as a filler, the strength of the geopolymer cured body can be further improved.

[0101] The shape of the filler (inorganic particles) is not particularly limited and may be spherical, amorphous, or flaky, with spherical being preferred. Making the inorganic particles spherical can improve the fluidity of the geopolymer manufacturing composition after compounding. The structure of the inorganic particles is not particularly limited and may be solid or hollow. Hollow refers to a structure having a cavity inside surrounded by an outer shell. The internal cavity may be sealed, or a part of it may be in communication with the outside.

[0102] The average particle size of the filler (inorganic particles) is preferably in the range of 0.1 to 100 μm, more preferably in the range of 1 to 50 μm, and even more preferably in the range of 5 to 15 μm.

[0103] The bulk density of fillers (inorganic particles) is 0.001 to 1.000 g / cm³. 3 A range of 0.010 to 0.500 g / cm³ is preferred. 3 A range of 0.050 to 0.200 g / cm³ is more preferable. 3 A range of this magnitude is even more preferable. The method for measuring bulk density is the same as described above.

[0104] The content of fillers (inorganic particles) is not particularly limited, but is preferably 5% or more by mass, 10% or more by mass, 20% or more by mass, 25% or more by mass, 30% or more by mass, etc., relative to the total mass of the geopolymer manufacturing composition, and preferably 60% or less by mass, 55% or less by mass, 50% or less by mass, etc. Keeping the inorganic particle content within the above range can further improve the thermal insulation properties of the cured geopolymer.

[0105] (Other ingredients) The geopolymer manufacturing composition may contain other components as long as they do not impair the effects of the present invention. Examples of other components include pH adjusters, fluidizers, shrinkage reducers, rust inhibitors, waterproofing agents, setting retarders, defoamers, dust reducers, and pigments. It may also contain glass fibers or the like as a reinforcing material.

[0106] The content of other components is not particularly limited, but is preferably in the range of 1 to 10% by mass relative to the total mass of the geopolymer manufacturing composition.

[0107] 2-2-2. Curing Step The curing step involves mixing (kneading) each component of the geopolymer manufacturing composition described above, drying and curing it to obtain a geopolymer cured body, i.e., a thermal insulation layer 12. In other words, the geopolymer cured body, which is the thermal insulation layer 12, can be formed by removing water from the geopolymer manufacturing composition.

[0108] The mixing conditions for each component of the geopolymer manufacturing composition are not particularly limited as long as a cured geopolymer can be obtained. The mixing method may involve kneading using a mortar mixer or a concrete mixer. After kneading, curing is preferably carried out at room temperature or while heating. The curing time varies with temperature, with lower temperatures requiring longer curing times. For example, the curing time is generally preferably 7 days or more at room temperature and 3 to 4 days at 60°C.

[0109] 2-2-2-1. Content of each component In the curing step, the content of each component, based on the total mass of the geopolymer cured product, when the geopolymer cured product is manufactured using the geopolymer manufacturing composition described above, will be explained.

[0110] (Aluminosilicate) The aluminosilicate content is preferably 1% by mass or more, 5% by mass or more, 10% by mass or more, and preferably 30% by mass or less, 50% by mass or less, 70% by mass or less, based on the total mass of the geopolymer cured product.

[0111] (Aerogel) The aerogel content is preferably more than 0% by mass, 5% or more by mass, 10% or more by mass, etc., relative to the total mass of the geopolymer cured product, and preferably 50% or less by mass, 40% or less by mass, 30% or less by mass, etc.

[0112] (Infrared absorbing filler) The amount of infrared absorbing filler is preferably more than 0% by mass, 1% or more by mass, 2% or more by mass, etc., relative to the total mass of the geopolymer cured body, and preferably 30% or less by mass, 20% or less by mass, 15% or less by mass, etc.

[0113] (Filler) The filler content is preferably more than 10% by mass, 20% or more by mass, or 30% or more by mass, relative to the total mass of the geopolymer cured product, and preferably 70% or less by mass, 60% or less by mass, or 50% or less by mass.

[0114] In this embodiment, an example is shown in which the geopolymer cured body is produced using the geopolymer production composition described above, but the embodiment is not limited to this. That is, the geopolymer cured body of this embodiment may contain a geopolymer and be porous.

[0115] 2-3.Lamination process The lamination process involves laminating the silicone foam layer 11 and the heat insulating layer 12 as described above. The lamination method is not particularly limited and includes methods using double-sided tape or adhesive, and methods using pouches. From the viewpoint of reducing the effects of distortion on the laminate 10, the method of lamination using pouches is more preferable. More specifically, after laminating the silicone foam layer 11 and the heat insulating layer 12, the laminate is pouched using PET film, PE film, etc. The pouching method is not particularly limited and includes methods such as skin packing and deep-draw vacuum packaging.

[0116] 3. Applications of laminates The laminate 10 of this embodiment has excellent heat insulation and cushioning properties, making it suitable for use as a heat insulating material for energy storage devices such as lithium-ion batteries and lead-acid batteries used in various applications including housing, vehicles, and industrial use. In particular, it can be suitably used as an inter-cell heat insulating material for batteries used in electric vehicles.

[0117] The energy storage device of this embodiment includes the laminated body described above. Therefore, it is possible to provide an energy storage device with excellent heat insulation properties. [Examples]

[0118] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the embodiments described below.

[0119] <Silicone foam layer> • Silicone foam: NanNex TL7404, manufactured by Inoac Corporation.

[0120] <Insulation layer> [Example 1: Geopolymer cured body] (Preparation of compositions for geopolymer production) The components of the geopolymer manufacturing composition were prepared as follows. • Aluminosilicate metakaolin {Meta-kaolin: Manufactured by Takehara Chemical Industry Co., Ltd., produced by heating NN kaolin clay at 800°C for 10 hours to make it amorphous.} • Aerogel {Silica aerogel: Manufactured by Cabot Corporation, P200} • Infrared absorbing filler {Silicon carbide: Manufactured by Shin-Etsu Electric Smelting Co., Ltd.} • Acidic surfactants Concentrated phosphoric acid solution (85%) - manufactured by Kanto Chemical Co., Ltd. • Distilled water · Filler {Wet silica: Manufactured by Evonik Japan Co., Ltd., ULTRSIL VN3} ·Reinforcement material {Glass fiber: manufactured by Nitto Boseki Co., Ltd., chopped strand CS6J-888}

[0121] The solid components described above were mixed in the proportions shown in Table 1 below. The resulting mixture was added to a concentrated phosphoric acid aqueous solution while being stirred under the following stirring conditions to prepare a composition for geopolymer production. (stirring conditions) Mixer: Manufactured by Shinto Kagaku Co., Ltd., Three-One Motor BL600 Rotation speed: 790 rpm Stirring time: 20 minutes

[0122] (hardening process) The obtained geopolymer manufacturing composition was cured under the following conditions. Specifically, the geopolymer manufacturing composition was poured into a silicone mold, and heated while being pressed with a 100 mm x 100 mm spacer to form pieces with thicknesses of 4 mm and 3 mm. After demolding, the pieces were cured in a constant temperature and humidity chamber to produce cured geopolymer bodies. (Heating conditions) Temperature: 115℃ Duration: 20 minutes (Curing conditions) Temperature: 23℃ Relative humidity: 55% Time: 24 hours

[0123] [Table 1]

[0124] [Example 2: Inorganic fiber substrate] • Aerogel blanket {Manufactured by Guangdong Alison Technology Co., Ltd., DYT0803}

[0125] [Example 3: Inorganic Substrate] • Silica-based porous sheet {Siltherm Japan Co., Ltd., Siltherm Silcin}

[0126] For each example, the geopolymer cured body, inorganic fiber substrate, and inorganic substrate were subjected to apparent density measurement, thermal conductivity testing, compression testing, and thermal insulation testing using the methods described below. The evaluation results are shown in Table 2 below.

[0127] (Apparent density) The apparent density was measured using a method compliant with JIS K7222:2005 "Foamed plastics and rubber - Method for determining apparent density".

[0128] (Thermal conductivity) The thermal conductivity was measured using a thermal conductivity measuring device (HC-074 F200, manufactured by Eiko Seiki Co., Ltd.). More specifically, the test sample for each example (3 mm thick, 100 mm square) was placed in the center, and the remaining space was filled with insulating material (4 mm thick) (32 mW / m·K) (FOLEC, manufactured by Inoac Corporation) for measurement.

[0129] (Compression test) For each example, a test sample (3 mm thick, 10 mm in diameter) was compressed across its entire surface at a compression speed of 1 mm / min using an Autograph (AG-X 10kN, manufactured by Shimadzu Corporation), and the compressive strength at 5% compression (5% compressive strength) was measured.

[0130] (Thermal insulation test) Test samples (3 mm thick, 100 mm square) of the geopolymer cured body, inorganic fiber substrate, and inorganic substrate from each example were heated for 5 minutes on a 500°C hot plate (C-MAG HP4, IKA Corporation). Then, the surface temperature of the center of each test sample was measured from a height of 200 mm using a thermal imaging radiation thermometer (FLIR TG167, FLIR Corporation).

[0131] (Evaluation criteria for thermal insulation performance) A: Surface temperature below 230°C B: Surface temperature exceeds 230°C

[0132] [Table 2]

[0133] <Laminate> The silicone foam layer and the heat insulating layer manufactured by the method described above were stacked and laminated to obtain the laminates of each example.

[0134] Durability tests were conducted on test samples of the laminated bodies for each example (50 mm x 50 mm, silicone foam layer thickness: 3 mm, insulation layer thickness: 4 mm) using the method described below. The total thickness of each test sample, the thickness of the insulation layer, and the thickness of the silicone foam layer were measured before and after the test, and the thickness change rate was calculated using the formula below. The evaluation results are shown in Table 3 below. Rate of change (%) = {(thickness before test) - (thickness after test)} / (thickness before test) × 100

[0135] (Durability test) INOAC method Test environment: 25℃ × 55%Rh (1) Compressed to 3.0kN at 500N / min (2) Released up to 1.5kN at 500N / min (3) Repeat (1) → (2) 30 times. (4) Released at 1 mm / min up to 0.1 kN and held for 60 seconds. (5) Compressed to 9.5kN at 100N / min and held for 60 seconds.

[0136] [Table 3]

[0137] In each of the embodiments, the overall thickness change rate was 15% or less, indicating excellent durability. [Industrial applicability]

[0138] The laminate of the present invention has excellent heat insulation and cushioning properties, and is therefore suitable for use as a heat insulating material for energy storage devices such as lithium-ion batteries and lead-acid batteries used in various applications including housing, vehicles, and industrial use. In particular, it is suitable for use as an inter-cell heat insulating material for batteries used in electric vehicles. [Explanation of Symbols]

[0139] 10 Laminate 11 Silicone foam layer 12. Insulation layer

Claims

1. It comprises a silicone foam layer and a thermal insulation layer laminated on the silicone foam layer, A laminate in which the aforementioned insulating layer is an inorganic porous material.

2. The laminate according to claim 1, wherein the thermal insulation layer includes a geopolymer cured body.

3. The laminate according to claim 1, wherein the 5% compressive strength is 0.15 MPa or more.

4. A power storage device comprising a laminate according to any one of claims 1 to 3.

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