Aerogel heat insulation sheet loaded with thermal response fire extinguishing agent microcapsules as well as preparation method and application of aerogel heat insulation sheet

Abstract

The invention relates to an aerogel heat insulation sheet loaded with a thermal response fire extinguishing agent microcapsule as well as a preparation method and application of the aerogel heat insulation sheet, and belongs to the fields of new materials and the like, and the aerogel heat insulation sheet comprises the fire extinguishing agent microcapsule, a silicon dioxide-based aerogel fiber felt and an inorganic binder. Aiming at the problem of single function of an aerogel lithium ion battery heat insulation sheet, early fire extinguishing inhibition of lithium ion battery thermal runaway is realized through heat absorption gasification and fire extinguishing of a fire extinguishing agent in a fire extinguishing agent microcapsule; in addition, the high-temperature-resistant aerogel fiber material is used for inhibiting the propagation of a large amount of heat generated by the thermal runaway of the battery, and the propagation of the thermal runaway between the battery modules is slowed down. The battery heat insulation sheet prepared by the method can provide battery thermal safety for a longer period, and is beneficial to application. And the fire extinguishing agent microcapsule loaded on the heat insulation sheet can release the fire extinguishing agent at an adjustable temperature, and the silicon dioxide-based aerogel fiber felt not only has good elasticity, but also is wide and adjustable in thickness, low in manufacturing cost and good in temperature resistance.

Description

Technical Field

[0001] The invention belongs to the field of preparation of new materials, and particularly relates to an aerogel heat-insulating sheet loaded with heat-responsive fire-extinguishing agent microcapsules, and a preparation method and application thereof. Background Art

[0002] A car requires a lot of power to drive. In order to ensure normal driving, new energy vehicles powered by electricity need the battery compartment to provide a large current for a long time to ensure the supply of power. Since the battery energy storage part and the energy conversion part of the battery pack exist in the same space, it is easy to cause a chain reaction of exothermic reactions in the case of overcharging, puncture, collision, etc., causing thermal runaway accidents such as smoke, fire and even explosion. Thermal runaway is the most serious safety accident of power batteries and directly threatens the life safety of users. The problem of thermal runaway propagation of battery packs is mainly solved through thermal protection technology.

[0003] In addition to improving the safety performance of internal battery materials, the safety research of external components is also an important part of battery thermal protection technology. Aerogel materials, as the world's lowest density solid material, have extremely high porosity and extremely low thermal conductivity, and have been widely used in aerospace, aviation, automobiles, new energy and clothing. Aerogel is a nanoporous material formed by the mutual accumulation of colloidal particles. Placing aerogel felt as an insulating material between battery cells can achieve good insulation and light weight. In addition, some fire extinguishing agents are used in battery boxes. Halon liquid fire extinguishing agent has the advantages of high fire extinguishing efficiency, non-conductivity, stable chemical properties and no pollution to damaged / victims. It is a widely used fire extinguishing agent. At present, halon liquid fire extinguishing agent mainly exists in liquid state and is stored in pressure container bottles when used, but the injection requires higher pressure and many accessories. Therefore, some studies have applied microencapsulation of liquid fire extinguishing agents to some fire extinguishing fields.

[0004] Halon liquid fire extinguishing agents also have the characteristics of low boiling point and high volatility. For this reason, a highly durable shell with low permeability can be used. The shell can extend the long-term stability of the microcapsule, allowing the halogenated liquid fire extinguishing agent encapsulated inside the shell to maintain its properties during storage and use. For example, a Chinese patent document with publication number CN 116870415 A discloses a fire extinguishing microcapsule, which includes a core and a shell layer covering the core, the composition of the core includes a perfluorinated fire extinguishing agent, and the composition of the shell layer is at least one polymer material selected from polystyrene, polycaprolactone, etc. In this patent document, the core material of the fire extinguishing microcapsule is a perfluorinated fire extinguishing agent, and the wall material includes polymer materials such as polystyrene, which are used in thermally conductive potting glue. The microcapsule is heated and ruptured in the early stage of the battery pack runaway, releasing a perfluorinated fire extinguishing agent, which can meet the fire prevention and extinguishing needs of the battery in the early stage of thermal runaway, but its continuous suppression of thermal runaway cells still needs to be further improved. Summary of the invention

[0005] Based on the above background, the purpose of the present invention is to provide an aerogel insulation sheet loaded with thermally responsive fire extinguishing agent microcapsules and its preparation method and application. The aerogel insulation sheet of the present invention has good fire prevention and extinguishing performance, and is applied to lithium-ion batteries, etc., and can provide battery thermal safety for a longer period of time.

[0006] The present invention provides an aerogel heat-insulating sheet loaded with heat-responsive fire-extinguishing agent microcapsules, comprising a silica-based aerogel fiber felt carrier, and fire-extinguishing agent microcapsules loaded on the carrier via an inorganic binder;

[0007] The core material of the fire extinguishing agent microcapsule comprises a halogenated alkane fire extinguishing agent, and the wall material comprises polyurea.

[0008] As a preferred embodiment of the present invention, the silica-based aerogel fiber felt carrier comprises a fiber felt and a silica-based aerogel skeleton distributed inside the fiber felt.

[0009] As a preferred embodiment of the present invention, in the silica-based aerogel fiber felt carrier, the fiber felt is one or more of aluminum silicate fiber felt, mullite fiber felt, silicon carbide fiber felt and zirconium oxide fiber felt.

[0010] As a preferred embodiment of the present invention, in the fire extinguishing agent microcapsules, the halogenated alkane fire extinguishing agent is one or more of perfluorohexanone, dibromomethane, 2-bromo-3,3,3-trifluoropropylene, tetrafluorodibromoethane and 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, preferably perfluorohexanone.

[0011] As a preferred embodiment of the present invention, the diameter of the fire extinguishing agent microcapsules is between 10 and 120 μm, preferably between 20 and 100 μm.

[0012] The present invention provides a method for preparing an aerogel thermal insulation sheet loaded with thermal responsive fire extinguishing agent microcapsules as described above, comprising the following steps:

[0013] Providing silica-based aerogel fiber felt;

[0014] Providing fire extinguishing agent microcapsules, wherein the core material comprises a halocarbon fire extinguishing agent and the wall material comprises polyurea;

[0015] The fire extinguishing agent microcapsules are dispersed in an inorganic binder, and then coated on the surface of the silica-based aerogel fiber felt, and then dried to obtain the aerogel thermal insulation sheet.

[0016] As a preferred embodiment of the present invention, the silica-based aerogel fiber felt is obtained according to the following steps:

[0017] The aluminum source, the silicon source and water are mixed and then hydrolyzed to obtain a hydrolyzate;

[0018] The fiber felt is immersed in the hydrolyzed solution to form a wet gel in the fiber felt, and after aging and drying, a silica-based aerogel fiber felt is obtained.

[0019] As a preferred embodiment of the present invention, in the process of obtaining the silica-based aerogel fiber felt, the silicon source is one or more of tetraethyl orthosilicate, tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane and sodium silicate, preferably tetraethyl orthosilicate; the aluminum source is one or more of aluminum chloride, aluminum nitrate, aluminum oxide and aluminum phosphide, preferably aluminum chloride.

[0020] As a preferred embodiment of the present invention, during the process of obtaining the silica-based aerogel fiber felt, the hydrolyzate also includes a catalyst and / or a coagulant; the coagulant is one or more of propylene oxide and ammonia water; the catalyst is one or more of hydrochloric acid and sulfuric acid.

[0021] As a preferred embodiment of the present invention, the fire extinguishing agent microcapsules are obtained according to the following steps:

[0022] Providing an aqueous emulsion containing a surfactant; providing an oil phase solution containing a haloalkane fire extinguishing agent and an isocyanate; adding the oil phase solution to the aqueous emulsion to form an oil-in-water emulsion;

[0023] The amino compound is added to the oil-in-water emulsion, stirred to react, and the fire extinguishing agent microcapsules are obtained through separation.

[0024] As a preferred embodiment of the present invention, in the process of obtaining the fire extinguishing agent microcapsules, the surfactant is one or more of dodecyl sulfate, dodecylbenzene sulfonate, sorbitan oleate, polysorbate-20, polysorbate-60 and dodecylphenol polyoxyethylene ether;

[0025] The isocyanate is isophorone diisocyanate; and the amino compound is diethylenetriamine.

[0026] As a preferred embodiment of the present invention, the oil-in-water emulsion further includes an initiator; the initiator is one or more of dibutyltin dilaurate, dibutyltin diacetate, stannous isooctanoate, zinc isooctanoate and bismuth isooctanoate.

[0027] As a preferred embodiment of the present invention, the mass ratio of the fire extinguishing agent microcapsules to the inorganic binder is 1:4-8, preferably 1:5; and the drying temperature of the aerogel thermal insulation sheet is 20-150°C.

[0028] As a preferred embodiment of the present invention, the aerogel insulation sheet obtained by drying comprises: naturally drying the coated material at room temperature for 24 hours, raising the temperature to 80-90°C and drying for 0.5-1 hour, then raising the temperature to 130-150°C and drying for 1 hour, and finally naturally cooling to obtain the aerogel insulation sheet.

[0029] Furthermore, the present invention provides the use of the aerogel thermal insulation sheet as described above or the aerogel thermal insulation sheet obtained by the preparation method in thermal runaway protection of batteries.

[0030] The aerogel insulation sheet of the present invention includes fire extinguishing agent microcapsules, silica-based aerogel fiber felt, and inorganic binder. The inorganic binder is mainly used to combine the high-temperature resistant aerogel insulation material and the microencapsulated halogenated extinguishing agent to form an aerogel insulation sheet loaded with heat-responsive fire extinguishing agent microcapsules. Some traditional battery insulation materials can only achieve the effect of suppressing the spread of thermal runaway after thermal runaway occurs, while the present application can achieve early suppression or delay of thermal runaway of single cells after loading fire extinguishing agent microcapsules (especially microcapsules with the most suitable response temperature); if thermal runaway is still triggered, the high-temperature resistant aerogel insulation sheet can be used to prevent the spread of thermal runaway in the battery module. Compared with traditional battery insulation materials, the present invention uses silica-based aerogel fiber felt insulation materials, which can play a role in blocking the spread of thermal runaway at a thinner thickness, which is conducive to expanding the safety cycle of the battery, so that the battery can be effectively protected from fire and fire in the early and late stages of thermal runaway. It can be seen that the innovation of this application is mainly reflected in the coordinated improvement of thermal protection of battery insulation materials, integrating "active + passive" fire protection functions, which is conducive to its application in battery thermal runaway protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a scanning electron microscope image of the fire extinguishing agent microcapsule prepared in Example 1;

[0032] Figure 2 This is the infrared spectrum of the fire extinguishing agent microcapsules prepared in Example 1;

[0033] Figure 3 The infrared spectra of the fire extinguishing agent microcapsules prepared with different monomer ratios of the wall material in Example 1, 0.22, 0.32, 0.42, 0.64, 0.68 represent different amounts of isophorone diisocyanate in grams;

[0034] Figure 4 The thermogravimetric diagram of the fire extinguishing agent microcapsules prepared with different monomer ratio wall materials in Example 1, 0.22, 0.32, 0.42, 0.64, 0.68 represent different amounts of isophorone diisocyanate in grams;

[0035] Figure 5This is a particle size diagram of the fire extinguishing agent microcapsules prepared in Example 1;

[0036] Figure 6 This is a compression cycle diagram for preparing high temperature resistant aerogel fiber felt in Example 1;

[0037] Figure 7 This is a test diagram of the thermal insulation performance of the high temperature section of the high temperature resistant aerogel fiber felt prepared in Example 1 (thickness 10 mm);

[0038] Figure 8 It is a structural schematic diagram of the high temperature section thermal insulation performance test device;

[0039] Fig. 9 This is a test diagram of the thermal insulation performance of the high temperature section of the high temperature resistant aerogel fiber felt prepared in Example 1 (thickness 10 mm);

[0040] Fig.10 The test results of the aerogel insulation sheet prepared in Example 1 for battery thermal runaway protection. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The present invention provides an aerogel heat-insulating sheet loaded with heat-responsive fire-extinguishing agent microcapsules, comprising a silica-based aerogel fiber felt carrier, and fire-extinguishing agent microcapsules loaded on the carrier via an inorganic binder;

[0043] The core material of the fire extinguishing agent microcapsule comprises a halogenated alkane fire extinguishing agent, and the wall material comprises polyurea.

[0044] The aerogel thermal insulation sheet provided by the present invention has good fire prevention and fire extinguishing performance, and is applied to lithium ion batteries and the like, and can provide battery thermal safety for a longer period.

[0045] The aerogel heat insulation sheet provided in the embodiment of the present invention uses high temperature resistant silica-based aerogel fiber felt as a carrier, and is combined with a high temperature resistant inorganic binder to load fire extinguishing agent microcapsules.

[0046] In an embodiment of the present invention, the silica-based aerogel fiber felt carrier includes a fiber felt, and a silica-based aerogel skeleton is distributed inside the fiber felt; this high-temperature resistant aerogel fiber composite material can inhibit the propagation of a large amount of heat generated by thermal runaway of the battery, thereby slowing down the propagation of thermal runaway between battery modules. In the silica-based aerogel fiber felt carrier, the fiber felt may be one or more of aluminum silicate fiber felt, mullite fiber felt, silicon carbide fiber felt and zirconium oxide fiber felt, preferably aluminum silicate fiber felt. The silica-based aerogel skeleton described in the embodiment of the present invention is preferably composed of nano-spherical aerogel secondary particles, and it is further preferred that Si-O-Al bonds exist, and its high temperature resistance is better.

[0047] In addition, the aerogel thermal insulation sheet described in the embodiment of the present invention includes fire extinguishing agent microcapsules and inorganic binders. The core material of the fire extinguishing agent microcapsules includes a halocarbon fire extinguishing agent, and the wall material includes polyurea. The halocarbon fire extinguishing agent in the fire extinguishing agent microcapsules absorbs heat and gasifies, extinguishes the fire, and can achieve early fire extinguishing and suppression of thermal runaway of lithium-ion batteries.

[0048] In an embodiment of the present invention, the fire extinguishing agent microcapsules are made of haloalkane fire extinguishing agent as the core material; the haloalkane fire extinguishing agent is preferably one or more of perfluorohexanone, dibromomethane, 2-bromo-3,3,3-trifluoropropylene and tetrafluorodibromoethane, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, more preferably perfluorohexanone. The wall material of the fire extinguishing agent microcapsules includes polyurea, which is usually an elastomeric substance generated by the reaction of isocyanate and amino compounds. The fire extinguishing agent microcapsules loaded by the embodiment of the present invention are thermally responsive, and the temperature at which the haloalkane fire extinguishing agent is released is adjustable. Preferably, the diameter of the fire extinguishing agent microcapsules is between 10 and 120 μm, further between 20 and 100 μm, and more preferably between 40 and 80 μm.

[0049] In addition, the inorganic binder described in the preferred embodiment of the present invention is an inorganic polymer adhesive formed by high temperature and high pressure polymerization of inorganic raw materials such as aluminum phosphate, magnesium silicate, sodium silicate, fire retardant, inorganic polymer polymerizer, etc. Its heat-resistant bonding temperature can reach 1300°C, and it has the characteristics of non-combustion, good solvent resistance, and high bonding strength.

[0050] In some embodiments, the thickness of the aerogel insulation sheet loaded with heat-responsive fire extinguishing agent microcapsules may be 3-4 mm, wherein the thickness of the aerogel insulation sheet is generally 2-3 mm. After loading the fire extinguishing agent microcapsules, the thickness of the loaded aerogel insulation sheet increases due to the particle size of the fire extinguishing agent microcapsules themselves. The insulation sheet is used in the battery module, so it cannot be too thick, otherwise it will significantly reduce the energy density of the battery module. The density of the aerogel insulation sheet without loaded fire extinguishing capsules is generally 0.18 g / cm3 After the fire extinguishing agent microcapsules are coated on the surface, the density of the loaded aerogel insulation sheet will increase to 0.3-0.4 g / cm 3 .

[0051] For a 10mm load insulation sheet, at a deformation of 40%, the stress is about 8MPa. It can withstand a deformation of 10%~50% and rebound to the initial height (Note: The reason for using a 10mm thick sample for the elastic test of the load insulation sheet is that under different strains, the actual deformation has an obvious span. For example, for a 10mm sample, a 10% deformation is 1mm, and a 40% deformation is 4mm. If for very thin samples such as 2~4mm, the actual deformation under different strains is not much different, and the relative error of the test is relatively large).

[0052] Accordingly, the embodiment of the present invention provides a method for preparing an aerogel thermal insulation sheet loaded with thermally responsive fire extinguishing agent microcapsules as described above, comprising the following steps:

[0053] Providing silica-based aerogel fiber felt;

[0054] Providing fire extinguishing agent microcapsules, wherein the core material comprises a halocarbon fire extinguishing agent and the wall material comprises polyurea;

[0055] The fire extinguishing agent microcapsules are dispersed in an inorganic binder, and then coated on the surface of the silica-based aerogel fiber felt, and then dried to obtain the aerogel thermal insulation sheet.

[0056] The embodiment of the present invention prepares a high temperature resistant silica-based aerogel fiber felt, and the specific steps are as follows:

[0057] S1, prepare the raw materials of high temperature resistant aerogel fiber felt:

[0058] The raw materials of the high temperature resistant aerogel fiber felt preferably include the following components: anhydrous ethanol, water (deionized water is generally used in the laboratory, the same below), a silicon source, an aluminum source, a coagulant, a fiber felt and other components, wherein the other components include a catalyst.

[0059] And it is prepared according to the following volume ratio: the ratio of anhydrous ethanol, water, silicon source, coagulant, and catalyst is 60: (4-6): (22-25): (55-60): (3-5), and the preferred volume ratio is 60: (4-6): 23: 58: 4; the molar ratio of the silicon source to the aluminum source is preferably 1: 2-5, and more preferably 1: 3.

[0060] Specifically, the silicon source may be one or more of tetraethyl orthosilicate, tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane and sodium silicate, preferably tetraethyl orthosilicate; the aluminum source may be one or more of aluminum chloride, aluminum nitrate, aluminum oxide and aluminum phosphide, preferably aluminum chloride. The coagulant is preferably one or more of propylene oxide and ammonia water; the catalyst is preferably one or more of hydrochloric acid and sulfuric acid.

[0061] The fiber felt is preferably one or more of aluminum silicate fiber felt, mullite fiber felt, silicon carbide fiber felt and zirconium oxide fiber felt, and is further aluminum silicate fiber felt. According to scanning electron microscopy images, the diameter of the aluminum silicate fibers in the fiber felt of some embodiments of the present invention is distributed in the range of 4 to 10 μm, and the density of the fiber felt is 0.15 g / cm 3 The thermal conductivity at room temperature is 0.04 W / (mK). The temperature resistance of aluminum silicate felt reaches 1000°C, and the maximum operating temperature can even reach 1300°C. It can maintain good elasticity and stability at high temperatures and is not prone to thermal decomposition and oxidation reactions.

[0062] S2, prepare high temperature resistant aerogel hydrolyzate:

[0063] The raw materials of step S1 are mixed evenly and fully hydrolyzed according to the aluminum source and the silicon source, and then mixed for 8 to 10 hours to complete the preparation of the high temperature resistant aerogel hydrolyzate A1. The mixing is carried out at a room temperature of 20 to 30°C, and the specific mixing process is as follows:

[0064] Anhydrous ethanol, water, a silicon source and a catalyst may be mixed in proportion to obtain a silicon hydrolyzate; anhydrous ethanol, water and an aluminum source may be mixed in proportion to obtain an aluminum hydrolyzate.

[0065] Specifically, the volume ratio of anhydrous ethanol: water: silicon source: catalyst is 30:2:12:2, and the hydrolysis is carried out at room temperature for 2 to 4 hours. The volume ratio of anhydrous ethanol to water is preferably 12:5, and then an aluminum precursor (mostly aluminum chloride hexahydrate) is added, and heated and stirred in a water bath at 50°C. The molar ratio of the aluminum-silicon precursor is maintained in the range of (3 to 5): 1, and the aluminum hydrolyzate and the silicon hydrolyzate are mixed and stirred for 8 to 10 hours. Among them, different silicon-aluminum ratios mainly affect the high temperature resistance of the thermal insulation sheet;

[0066] S3, Dip and Gel:

[0067] The coagulant is added into the hydrolyzate A1, and then the high temperature resistant fiber felt is immersed in the hydrolyzate A1 to form a wet gel inside the fiber felt, thereby preparing a wet gel product B1 of the high temperature resistant aerogel fiber felt.

[0068] In some embodiments, after adding the coagulant at room temperature, the hydrolyzate A1 will gel within 40 to 60 minutes.

[0069] S4, aging and drying:

[0070] The wet gel product B1 was first aged naturally in the air for 4 to 8 hours, then immersed in anhydrous ethanol for aging, and aged at 40°C for 18 to 24 hours. The aged wet gel product B1 was dried to remove the organic solvent, and a silica-based aerogel fiber felt was obtained, which was recorded as product C1.

[0071] The drying process is to place the wet gel / fiber composite in a sealed chamber and program the temperature of the chamber, which includes: heating from 30°C to 260~280°C at a rate of 1~3°C / min, keeping warm for 30~60 minutes, and then cooling naturally to complete the drying of the wet gel.

[0072] The density of the obtained silica-based aerogel fiber felt can be 0.18 g / cm 3 The thickness is preferably 3~4 mm; elasticity, for example: the stress is 7.8 MPa at 40% strain.

[0073] As a preferred embodiment of the present invention, the fire extinguishing agent microcapsules are prepared in the embodiment of the present invention, and the specific steps are as follows:

[0074] S5, prepare the raw materials of fire extinguishing agent microcapsules:

[0075] The raw materials of the fire extinguishing agent microcapsules preferably include the following components: halogenated alkane fire extinguishing agent, isophorone diisocyanate, methyl nonafluorobutyl ether, water, diethylenetriamine and other components, wherein the other components include a surfactant and an initiator.

[0076] The haloalkane fire extinguishing agent is one or more of perfluorohexanone, dibromomethane, 2-bromo-3,3,3-trifluoropropylene, tetrafluorodibromoethane and 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, preferably perfluorohexanone. The isocyanate is isophorone diisocyanate (IPDI for short); and the amino compound is diethylenetriamine (DETA).

[0077] The surfactant is preferably one or more of dodecyl sulfate, dodecylbenzene sulfonate, sorbitan oleate, polysorbate-20, polysorbate-60 and dodecylphenol polyoxyethylene ether, and more preferably dodecyl sulfate such as sodium dodecyl sulfate. The initiator is preferably one or more of dibutyltin dilaurate, dibutyltin diacetate, stannous isooctanoate, zinc isooctanoate and bismuth isooctanoate, and more preferably dibutyltin dilaurate.

[0078] S6, preparation of microcapsule wall material solution:

[0079] Prepare according to the following ratio: 4mL of halogenated alkane fire extinguishing agent, 0.42~0.64g of isophorone diisocyanate and 5g of methyl nonafluorobutyl ether, evenly mix to form oil phase wall material solution A2; under the condition of constant DETA dosage, the dosage of isophorone diisocyanate mainly affects the heat resistance temperature of microcapsules (reflected by TG). Methyl nonafluorobutyl ether is mainly a solvent, which can increase the solubility of perfluorohexanone in isophorone diisocyanate.

[0080] S7, preparation of emulsion:

[0081] Prepare according to the following ratio: 30 mL of water and 0.32 g of surfactant are uniformly mixed and stirred at a rate of 1500-2000 rpm for 1-10 min to form an aqueous emulsion B2. The oil phase wall material solution A2 can be slowly added dropwise to the aqueous emulsion B2 under high-speed stirring to form an oil-in-water emulsion C2. Then, 10 mL of water, 0.1 g of surfactant, and 0.5 g of initiator are stirred and mixed, and the oil-in-water emulsion C2 is added thereto to obtain emulsion D2.

[0082] S8, preparation of fire extinguishing agent microcapsules:

[0083] Preferably, 1.71 g of diethylenetriamine is added dropwise to the emulsion D2, stirred for reaction, and then the temperature of the reaction system is lowered to below 10°C. After reacting for 0.5 to 1 hour, the temperature of the reaction system is raised to 40 to 50°C. After the reaction is kept warm for 1.5 to 2.5 hours, the reaction solution is filtered to obtain granular fire extinguishing agent microcapsules (diethylenetriamine and isophorone diisocyanate are combined to form a polymer shell, and the haloalkane fire extinguishing agent is used as a core material and is coated with the polymer shell). The particles can be washed with deionized water and dried.

[0084] Specifically, the diameter of the fire extinguishing agent microcapsule may be between 10 and 120 μm, further between 20 and 100 μm, and more preferably between 40 and 80 μm.

[0085] The order of preparing the silica-based aerogel fiber felt and the fire extinguishing agent microcapsules in the embodiment of the present invention is not limited, and they are listed as steps S1 to S4 and steps S5 to S8 only for the sake of clear operation.

[0086] As a preferred solution of the present invention, there is also a painting process after step S8, namely:

[0087] S9, application of fire extinguishing agent microcapsules:

[0088] The fire extinguishing agent microcapsules obtained in step S8 can be dispersed in a high temperature resistant inorganic binder, and then uniformly coated on the surface of the high temperature resistant aerogel fiber felt. The inorganic bonding is as described above; the mass ratio of the fire extinguishing agent microcapsule solid to the high temperature resistant inorganic binder can be 1:4~8, and the preferred mass ratio is 1:5. Afterwards, the coated material is preferably dried naturally at room temperature for 24 hours, the temperature is increased to 80~100℃ and dried for 0.5~1h, and then the temperature is increased to 130~150℃ and dried for 1h, and naturally cooled to complete the drying of the inorganic binder to form the aerogel insulation sheet loaded with thermally responsive fire extinguishing agent microcapsules.

[0089] Furthermore, the present invention provides the use of the aerogel thermal insulation sheet as described above or the aerogel thermal insulation sheet obtained by the preparation method described above in battery thermal runaway protection. The battery thermal insulation sheet prepared by the method of the present invention can provide battery thermal safety for a longer period of time, which is convenient for application. Furthermore, the temperature at which the fire extinguishing agent microcapsules loaded with the aerogel thermal insulation sheet release the fire extinguishing agent is adjustable, and the silica-based aerogel fiber felt not only has good elasticity, but also has a wide range of adjustable thickness, low production cost, and good temperature resistance.

[0090] In order to better illustrate the present invention, the following examples are further illustrated. Unless otherwise specified, the various reagents and raw materials used in the present invention are all commercially available products or products that can be made by recognized methods. Unless otherwise specified, the proportions involved are all mass proportions. Among them, the diameter of the aluminum silicate fiber of the fiber mat is distributed in 4~10 μm, and the density of the fiber mat is 0.15 g / cm 3 The thermal conductivity at room temperature is 0.04 W / (mK). Inorganic binder is an inorganic polymer adhesive formed by high temperature and high pressure polymerization of inorganic raw materials such as aluminum phosphate, magnesium silicate, sodium silicate, fire retardant, inorganic polymer polymerizer, etc.; its heat-resistant bonding temperature reaches 1300℃.

[0091] Example 1

[0092] 1) Preparation:

[0093] Prepare silicon hydrolysis solution according to the following volume parts: anhydrous ethanol, deionized water, silicon source ethyl orthosilicate, and catalyst in a ratio of 60:4:23:4; prepare aluminum hydrolysis solution according to the following volume parts: anhydrous ethanol, deionized water, and coagulant in a ratio of 60:25:58. When the volume of anhydrous ethanol in the aluminum hydrolysis solution is 60 mL and the hydrolysis solution is 1 part, the mass of aluminum source aluminum chloride is 24.14 g. Among them, the molar ratio of silicon source to aluminum source is 1:3.

[0094] 2) Prepare high temperature resistant aerogel hydrolyzate:

[0095] The raw materials of step 1 are mixed evenly according to the aluminum source and the silicon source, fully hydrolyzed, and then mixed for 8 hours to complete the preparation of the high temperature resistant aerogel hydrolyzate A1.

[0096] 3) Dipping and gelling:

[0097] The coagulant is added into the hydrolyzate A1, and then the aluminum silicate fiber felt is immersed in the hydrolyzate A1 to prepare a wet gel product B1 of high temperature resistant aerogel fiber felt.

[0098] Sol-gel method: The volume ratio of anhydrous ethanol: water: silicon source: catalyst is 30:2:12:2, and hydrolysis is carried out at room temperature for 2 hours. The volume ratio of anhydrous ethanol: water is 12:5, and then an aluminum precursor (aluminum chloride hexahydrate) is added, and heated and stirred in a water bath at 50 ℃. The molar ratio of aluminum silicon precursor is kept in the range of (3~5):1, and the aluminum hydrolyzate and silicon hydrolyzate are mixed and stirred for 8 hours. After propylene oxide (coagulant) is added to the mixed hydrolyzate at room temperature and a speed of about 200rpm, the hydrolyzate containing propylene oxide is poured into a container containing fiber felt in advance, so that the sol just submerges the fiber felt [this step is impregnation, the impregnation temperature is 25℃], and it is naturally gelled at room temperature (time is about 40min).

[0099] 4) Aging and drying:

[0100] The wet gel product B1 was first aged naturally in air for 8 hours, then immersed in anhydrous ethanol for aging, and aged for 18 hours at 40° C. The aged wet gel product B1 was dried to remove the organic solvent, thereby obtaining product C1.

[0101] After aging, the wet gel / fiber composite is placed in a sealed chamber and the temperature of the chamber is program-controlled. The program includes: heating from 30°C to 260°C at a rate of 1-3°C / min, keeping warm for 60 minutes, and then cooling naturally to complete the drying of the wet gel / fiber composite and obtain an aerogel insulation sheet.

[0102] 5) Prepare the raw materials of fire extinguishing agent microcapsules:

[0103] The raw materials of the fire extinguishing agent microcapsules include the following components: haloalkane fire extinguishing agent perfluorohexanone (the same in the following embodiments), isophorone diisocyanate, methyl nonafluorobutyl ether, deionized water, diethylenetriamine and other components. Other components include surfactants and initiators. The surfactant is selected as sodium dodecyl sulfate and the initiator is selected as dibutyltin dilaurate.

[0104] 6) Preparation of microcapsule wall material solution:

[0105] Prepare according to the following ratio: 4 mL of halogenated alkane fire extinguishing agent, 0.42 g of isophorone diisocyanate, and 5 g of methyl nonafluorobutyl ether are uniformly mixed to form an oil phase wall material solution A2;

[0106] 7) Preparation of emulsion:

[0107] Prepare according to the following ratio: 30 mL of deionized water and 0.32 g of surfactant are uniformly mixed and stirred at a rate of 2000 rpm for 10 min to form an aqueous phase emulsion B2. The oil phase wall material solution A2 is slowly added dropwise to the aqueous phase emulsion B2 under high-speed stirring to form an oil-in-water emulsion C2. Then 10 mL of deionized water, 0.1 g of sodium dodecyl sulfate, and 0.5 g of dibutyltin dilaurate are stirred and mixed, and then the oil-in-water emulsion C2 is added to obtain emulsion D2.

[0108] 8) Preparation of fire extinguishing agent microcapsules:

[0109] 1.71 g of diethylenetriamine was added dropwise to emulsion D2, and the mixture was stirred for reaction at a speed of 400 rpm. The temperature of the reaction system was then lowered to below 10°C. After the reaction for 1 hour, the temperature of the reaction system was raised to 45°C. After the reaction was kept warm for 2 hours, the reaction solution was filtered to obtain the fire extinguishing agent microcapsule particles. The particles were washed 4 times with deionized water and then dried.

[0110] 9) Application of fire extinguishing agent microcapsules:

[0111] The fire extinguishing agent microcapsules obtained in the above steps are dispersed in a high temperature resistant inorganic binder, and then evenly coated on the surface of the high temperature resistant aerogel fiber felt. The mass ratio of the fire extinguishing agent microcapsule solid to the high temperature resistant inorganic binder is 1:5. The coated material is then naturally dried at room temperature for 24 hours, the temperature is raised to 90°C for drying for 1 hour, and then the temperature is raised to 150°C for drying for 1 hour, and then naturally cooled to complete the drying of the inorganic binder to obtain an aerogel insulation sheet loaded with heat responsive fire extinguishing agent microcapsules.

[0112] In addition, in Example 1, fire extinguishing agent microcapsules were prepared using other polymer monomer ratios, specifically: the core material ratio ranged from 66.82% to 85.07% (the core material ratio obtained based on thermogravimetric results).

[0113] Example 2

[0114] 1) Preparation:

[0115] The silicon hydrolysate was prepared according to the following volume parts: the ratio of anhydrous ethanol, deionized water, silicon source, and catalyst was 60:4:23:4; the aluminum hydrolysate was prepared according to the following volume parts: the ratio of anhydrous ethanol, deionized water, and coagulant was 60:25:58. When the volume of anhydrous ethanol in the aluminum hydrolysate was 60 mL and the hydrolysate was 1 part, the mass of aluminum chloride was 24.14 g. Among them, the molar ratio of silicon source to aluminum source was 1:5.

[0116] 2) Prepare high temperature resistant aerogel hydrolyzate:

[0117] The raw materials of step 1 are mixed evenly according to the aluminum source and the silicon source, fully hydrolyzed, and then mixed for 8 hours to complete the preparation of the high temperature resistant aerogel hydrolyzate A1.

[0118] 3) Dipping and gelling:

[0119] The coagulant is added into the hydrolyzate A1, and then the aluminum silicate fiber felt is immersed in the hydrolyzate A1 to prepare a wet gel product B1 of high temperature resistant aerogel fiber felt.

[0120] 4) Aging and drying:

[0121] The wet gel product B1 was first aged naturally in air for 8 hours, then immersed in anhydrous ethanol for aging, and aged for 18 hours at 40° C. The aged wet gel product B1 was dried to remove the organic solvent, thereby obtaining product C1.

[0122] 5) Prepare the raw materials of fire extinguishing agent microcapsules:

[0123] The raw materials of the fire extinguishing agent microcapsules include the following components: halogenated alkane fire extinguishing agent, isophorone diisocyanate, methyl nonafluorobutyl ether, deionized water, diethylenetriamine and other components. Other components include surfactants and initiators. The surfactant is selected as sodium dodecyl sulfate and the initiator is selected as dibutyltin dilaurate.

[0124] 6) Preparation of microcapsule wall material solution:

[0125] Prepare according to the following ratio: 4 mL of liquid fire extinguishing agent, 0.64 g of isophorone diisocyanate, and 5 g of methyl nonafluorobutyl ether are uniformly mixed to form an oil phase wall material solution A2;

[0126] 7) Preparation of emulsion:

[0127] Prepare according to the following ratio: 30 mL of deionized water and 0.32 g of surfactant are uniformly mixed and stirred at a rate of 2000 rpm for 10 min to form an aqueous phase emulsion B2. The oil phase wall material solution A2 is slowly added dropwise to the aqueous phase emulsion B2 under high-speed stirring to form an oil-in-water emulsion C2. Then 10 mL of deionized water, 0.1 g of sodium dodecyl sulfate, and 0.5 g of dibutyltin dilaurate are stirred and mixed, and then the oil-in-water emulsion C2 is added to obtain emulsion D2.

[0128] 8) Preparation of microcapsules:

[0129] 1.71 g of diethylenetriamine was added dropwise to emulsion D2, and the mixture was stirred for reaction at a speed of 400 rpm. The temperature of the reaction system was then lowered to below 10°C. After the reaction for 1 hour, the temperature of the reaction system was raised to 45°C. After the reaction was kept warm for 2 hours, the reaction solution was filtered to obtain the fire extinguishing agent microcapsule particles. The particles were washed 4 times with deionized water and then dried.

[0130] 9) Application of fire extinguishing agent microcapsules:

[0131] The fire extinguishing agent microcapsules obtained in the above steps are dispersed in a high temperature resistant inorganic binder, and then evenly coated on the surface of the high temperature resistant aerogel fiber felt. The mass ratio of the fire extinguishing agent microcapsule solid to the high temperature resistant inorganic binder is 1:5. The coated material is then naturally dried at room temperature for 24 hours, the temperature is raised to 90°C for drying for 1 hour, and then the temperature is raised to 150°C for drying for 1 hour, and then naturally cooled to complete the drying of the inorganic binder to obtain an aerogel insulation sheet loaded with heat responsive fire extinguishing agent microcapsules.

[0132] Example 3

[0133] 1) Preparation:

[0134] The silicon hydrolysate was prepared according to the following volume parts: the ratio of anhydrous ethanol, deionized water, silicon source, and catalyst was 60:4:23:4; the aluminum hydrolysate was prepared according to the following volume parts: the ratio of anhydrous ethanol, deionized water, and coagulant was 60:25:58. When the volume of anhydrous ethanol in the aluminum hydrolysate was 60 mL and the hydrolysate was 1 part, the mass of aluminum chloride was 24.14 g. Among them, the molar ratio of silicon source to aluminum source was 1:3.

[0135] 2) Prepare high temperature resistant aerogel hydrolyzate:

[0136] The raw materials of step 1 are mixed evenly according to the aluminum source and the silicon source, fully hydrolyzed, and then mixed for 8 hours to complete the preparation of the high temperature resistant aerogel hydrolyzate A1.

[0137] 3) Dipping and gelling:

[0138] The coagulant is added into the hydrolyzate A1, and then the aluminum silicate fiber felt is immersed in the hydrolyzate A1 to prepare a wet gel product B1 of high temperature resistant aerogel fiber felt.

[0139] 4) Aging and drying:

[0140] The wet gel product B1 was first aged naturally in air for 8 hours, then immersed in anhydrous ethanol for aging, and aged for 18 hours at 40° C. The aged wet gel product B1 was dried to remove the organic solvent, thereby obtaining product C1.

[0141] 5) Prepare the raw materials of fire extinguishing agent microcapsules:

[0142] The raw materials of the fire extinguishing agent microcapsules include the following components: halogenated alkane fire extinguishing agent, isophorone diisocyanate, methyl nonafluorobutyl ether, deionized water, diethylenetriamine and other components. Other components include surfactants and initiators. The surfactant is selected as sodium dodecyl sulfate and the initiator is selected as dibutyltin dilaurate.

[0143] 6) Preparation of microcapsule wall material solution:

[0144] Prepare according to the following ratio: 4 mL of liquid fire extinguishing agent, 0.42 g of isophorone diisocyanate, and 10 g of methyl nonafluorobutyl ether are uniformly mixed to form an oil phase wall material solution A2;

[0145] 7) Preparation of emulsion:

[0146] Prepare according to the following ratio: 30mL of deionized water and 0.32g of surfactant are evenly mixed and stirred at a rate of 1500rpm for 1min to form an aqueous emulsion B2. The oil phase wall material solution A2 is slowly added dropwise to the aqueous emulsion B2 under high-speed stirring to form an oil-in-water emulsion C2. After 10mL of deionized water, 0.1g of sodium dodecyl sulfate and 0.5g of dibutyltin dilaurate are stirred and mixed, the oil-in-water emulsion C2 is added to obtain emulsion D2. The difference in this embodiment mainly lies in the rotation speed and the time of high-speed stirring; the particle size and distribution depend on the formation of the initial droplets, so the emulsification speed has a great influence on the particle size of the microcapsules. The greater the emulsification speed, the smaller the droplets formed and the less likely they are to aggregate, and the smaller and more uniform the particle size of the microcapsules formed. A more suitable rotation speed is 2000rpm. When it is lower than this value, the particle size distribution of the microcapsules is wider.

[0147] 8) Preparation of microcapsules:

[0148] 1.71 g of diethylenetriamine was added dropwise to emulsion D2, and the mixture was stirred for reaction at a speed of 400 rpm. The temperature of the reaction system was then lowered to below 10°C. After the reaction for 1 hour, the temperature of the reaction system was raised to 45°C. After the reaction was kept warm for 2 hours, the reaction solution was filtered to obtain the fire extinguishing agent microcapsule particles. The particles were washed 4 times with deionized water and then dried.

[0149] 9) Application of fire extinguishing agent microcapsules:

[0150] The fire extinguishing agent microcapsules obtained in the above steps are dispersed in a high temperature resistant inorganic binder, and then evenly coated on the surface of the high temperature resistant aerogel fiber felt. The mass ratio of the fire extinguishing agent microcapsule solid to the high temperature resistant inorganic binder is 1:5. The coated material is then naturally dried at room temperature for 24 hours, the temperature is raised to 90°C for drying for 1 hour, and then the temperature is raised to 150°C for drying for 1 hour, and then naturally cooled to complete the drying of the inorganic binder to obtain an aerogel insulation sheet loaded with heat responsive fire extinguishing agent microcapsules.

[0151] Figure 1 This is a scanning electron microscope image of the fire extinguishing agent microcapsules prepared in Example 1. This figure is a scanning electron microscope image (SEM) of the fire extinguishing agent microcapsules, which contains 0.42 g of isophorone diisocyanate; it can be seen that the fire extinguishing agent microcapsules prepared in Example 1 are spherical, with a diameter of about 40 μm.

[0152] Figure 2 This is the infrared spectrum of the fire extinguishing agent microcapsule prepared in Example 1 (the FTIR was measured using the KBr tablet method, where 0.42 represents the amount of isophorone diisocyanate in grams). It can be seen that at 1708 cm -1 The C=O bond at the bottom of the polymer shell indicates that perfluorohexanone is successfully encapsulated into the polymer shell. In addition, the CN bond comes from the polymer shell.

[0153] According to the preparation method of A2 / D2 in Example 1, other experimental groups prepared fire extinguishing agent microcapsules using various polymer monomer ratios, and the comparison results are as follows.

[0154] Figure 3 FTIR graph of fire extinguishing agent microcapsules prepared from different polymer monomers, where the intensity of the peak represents the proportion of the polymer shell in the fire extinguishing agent microcapsules; 0.22, 0.32, 0.42, 0.64, and 0.68 represent different amounts of isophorone diisocyanate in grams. Figure 3 It mainly explains the differences in the infrared spectra of microcapsules at different dosages of isophorone diisocyanate (IPDI). The specific differences are reflected in the relative prominence of each functional group (peak). Figure 3 The infrared spectra of microcapsule wall materials DETA and IPDI are also specially drawn to show their characteristic peaks.

[0155] Figure 4 This is the thermogravimetric diagram of the fire extinguishing agent microcapsule prepared in Example 1. The TG test conditions are: air atmosphere, starting from room temperature or 30°C, and heating to 800°C at a rate of 10°C / min. The thermogravimetric curve of the microcapsule shows that the temperature starting from 5% weight loss of the microcapsule is the heat resistance temperature. The use of microcapsule technology can increase the thermal stability of perfluorohexanone from the boiling point of 49.2°C to 180°C and above. The different proportions of monomers in the polymer shell will affect the heat resistance temperature of the fire extinguishing agent microcapsule, so there will be a series of curves.

[0156] Figure 5 This is a particle size diagram of the fire extinguishing agent microcapsules prepared in Example 1, wherein 0.42 g of isophorone diisocyanate is contained; the results illustrate the particle size distribution of the fire extinguishing agent microcapsules prepared in Example 1, and it can be seen that the diameters of most of the fire extinguishing agent microcapsules are between 10-120 μm.

[0157] Figure 6 This is a compression cycle diagram of the high temperature resistant aerogel fiber felt prepared in Example 1. This figure is a characterization of the mechanical properties of the high temperature resistant aerogel insulation sheet, in which 0.42g of isophorone diisocyanate is contained. Cyclic compression test conditions: The pressure sensor of the universal testing machine vertically compresses the sample at a speed of 60mm / min, and after reaching the set displacement (i.e. deformation), it leaves the sample at a speed of 60mm / min; the range of the pressure sensor is 5000N.

[0158] The results show that under different compression deformations (18~62%), the compression process curves can overlap, and can rebound to the initial height after a large deformation of 60%, proving that it has good elasticity.

[0159] Comparative Example 1

[0160] 1) Prepare aerogel hydrolysate:

[0161] The silicon hydrolyzate was prepared according to the following volume ratios: anhydrous ethanol, deionized water, silicon source, and catalyst were 60:4:23:4. The hydrolysis was carried out in a 30°C water bath for 2 h to complete the preparation of aerogel hydrolyzate A1.

[0162] 2) Dipping and gelling:

[0163] The coagulant is added into the hydrolyzate A1, and then the aluminum silicate fiber felt is immersed in the hydrolyzate A1 to prepare a wet gel product B1 of the aerogel fiber felt.

[0164] 3) Aging and drying:

[0165] The wet gel product B1 was first aged naturally in air for 8 hours, then immersed in anhydrous ethanol for aging, and aged for 18 hours at 40°C. The aged wet gel product B1 was dried to remove the organic solvent, and a comparative example 1 (i.e., a heat-insulating sheet without a fire-extinguishing capsule) was obtained.

[0166] The examples and comparative examples were subjected to thermal insulation tests, and the specific test methods are as follows:

[0167] Thermal insulation performance test method: The model of the infrared imager is FLIR A655SC.

[0168] M1, medium and high temperature insulation performance test method:

[0169] 1) Select a heating stage and infrared imager and calibrate them. The standard temperature measurement range of the infrared imager is -40~150℃;

[0170] 2) Set the temperature of the heating platform to 300°C and place the sample on the heating platform. Aim the infrared imager at the thickness direction of the sample and measure the temperature changes over time at three measuring points in the thickness direction.

[0171] according to Figure 7 It can be seen that the temperature of the cold surface remains basically unchanged after rising from room temperature to about 70°C. The temperature of the measuring point at the middle thickness position does not rise sharply, proving that the thermal insulation performance of the high temperature resistant aerogel fiber felt (Example 1: 0.42g of isophorone diisocyanate) is very stable in the medium and high temperature range.

[0172] The specific components of the test device are: heating table (temperature range: 25~400℃, temperature control accuracy 0.1℃), infrared imager. The infrared imager takes pictures of the temperature distribution of the sample thickness surface on the heating table from the front. The sample thickness is 10 mm, and the positions of the three measuring points are in the thickness direction, and the three points are taken at a consistent interval.

[0173] M2, high temperature section thermal insulation performance test method:

[0174] 1) If Figure 8 As shown, a butane spray gun with a flame temperature of 1200°C is used, the distance between the spray gun port and the high temperature resistant aerogel fiber felt is no more than 2 cm, and the standard temperature measurement range of the infrared imager is selected as the 150~650°C temperature measurement section.

[0175] 2) Aim the infrared imager at the cold surface of the sample and measure how the sample surface temperature changes over time.

[0176] Figure 8 is a schematic diagram of the characterization method. A butane flame spray gun is used to heat one side of the thermal insulation sheet, and an infrared imager is used to monitor the surface temperature of the other side. Three measuring points (middle, upper left, and lower right) are selected on the back. The measured temperatures are shown in Figure 2. Fig. 9 As shown (Example 1: 0.42 g of isophorone diisocyanate), after 5 minutes, the temperature at the center point of the back side fluctuates around 150°C, and the temperature of the surrounding area (upper left and lower right) of the flame is 120°C or below, proving that a 10 mm thick aerogel insulation material can withstand a temperature gradient of about 1000°C.

[0177] The aerogel insulation sheet loaded with fire extinguishing agent microcapsules prepared in Example 1 (containing 0.42 g of isophorone diisocyanate) and the aerogel insulation sheet prepared in the comparative example were used as insulation materials in a battery module consisting of four 58Ah square lithium-ion batteries and compared with a blank control group without any insulation measures. Fig.10 It can be found that the use of aerogel insulation sheets alone can increase the thermal runaway propagation time to 1951s, while after using aerogel insulation sheets loaded with fire extinguishing agent microcapsules, the thermal runaway propagation time between the entire battery module is 2907s.

[0178] It can be seen from the above embodiments that the aerogel insulation sheet provided by the embodiments of the present invention includes fire extinguishing agent microcapsules, silica-based aerogel fiber felt, and inorganic binders. The inorganic binder is mainly used to combine the high-temperature resistant aerogel insulation material and the microencapsulated halogenated hydrocarbon fire extinguishing agent to form an aerogel insulation sheet loaded with heat-responsive fire extinguishing agent microcapsules. After the present application is loaded with fire extinguishing agent microcapsules (especially microcapsules with the most suitable response temperature), early suppression or delay of thermal runaway of single cells can be achieved; if thermal runaway is still triggered, the use of a high-temperature resistant aerogel insulation sheet can prevent the propagation of thermal runaway in the battery module. Compared with traditional battery insulation materials, the present invention uses silica-based aerogel fiber felt insulation materials, which can play a role in blocking the propagation of thermal runaway at a thinner thickness, which is beneficial to extending the safety cycle of the battery, so that the battery can be effectively protected from fire and fire extinguishing in the early and late stages of thermal runaway.

[0179] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An aerogel insulation sheet loaded with heat-responsive fire extinguishing agent microcapsules, characterized in that: It includes a silica-based aerogel fiber felt carrier, and a fire extinguishing agent microcapsule loaded on the carrier through an inorganic binder; The core material of the fire extinguishing agent microcapsule comprises a halogenated alkane fire extinguishing agent, and the wall material comprises polyurea.

2. The aerogel thermal insulation sheet according to claim 1, characterized in that: The silica-based aerogel fiber felt carrier comprises a fiber felt and a silica-based aerogel skeleton distributed inside the fiber felt.

3. The aerogel thermal insulation sheet according to claim 2, characterized in that: In the silica-based aerogel fiber felt carrier, the fiber felt is one or more of aluminum silicate fiber felt, mullite fiber felt, silicon carbide fiber felt and zirconium oxide fiber felt.

4. The aerogel thermal insulation sheet according to any one of claims 1 to 3, characterized in that: The diameter of the fire extinguishing agent microcapsule is between 10 and 120 μm; the halogenated alkane fire extinguishing agent is one or more of perfluorohexanone, dibromomethane, 2-bromo-3,3,3-trifluoropropylene, tetrafluorodibromoethane and 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane.

5. The method for preparing the aerogel thermal insulation sheet loaded with heat-responsive fire extinguishing agent microcapsules according to any one of claims 1 to 4, characterized in that: The following steps are involved: Providing silica-based aerogel fiber felt; Providing fire extinguishing agent microcapsules, wherein the core material comprises a halocarbon fire extinguishing agent and the wall material comprises polyurea; The fire extinguishing agent microcapsules are dispersed in an inorganic binder, and then coated on the surface of the silica-based aerogel fiber felt, and then dried to obtain the aerogel thermal insulation sheet.

6. The preparation method according to claim 5, characterized in that: The silica-based aerogel fiber felt is obtained according to the following steps: The aluminum source, the silicon source and water are mixed and then hydrolyzed to obtain a hydrolyzate; The fiber felt is immersed in the hydrolyzed solution to form a wet gel in the fiber felt, and after aging and drying, a silica-based aerogel fiber felt is obtained.

7. The preparation method according to claim 6, characterized in that: The fire extinguishing agent microcapsules are obtained according to the following steps: Providing an aqueous emulsion containing a surfactant; providing an oil phase solution containing a haloalkane fire extinguishing agent and an isocyanate; adding the oil phase solution to the aqueous emulsion to form an oil-in-water emulsion; The amino compound is added to the oil-in-water emulsion, stirred to react, and the fire extinguishing agent microcapsules are obtained through separation.

8. The preparation method according to claim 7, characterized in that: In the process of obtaining the silica-based aerogel fiber felt, the silicon source is one or more of ethyl orthosilicate, tetramethoxysilane, methyltrimethoxysilane, methyltriethoxysilane and sodium silicate; the aluminum source is one or more of aluminum chloride, aluminum nitrate, aluminum oxide and aluminum phosphide; In the process of obtaining the fire extinguishing agent microcapsules, the surfactant is one or more of dodecyl sulfate, dodecylbenzene sulfonate, sorbitan oleate, polysorbate-20, polysorbate-60 and dodecylphenol polyoxyethylene ether; the isocyanate is isophorone diisocyanate; and the amino compound is diethylenetriamine.

9. The preparation method according to claim 8, characterized in that: The mass ratio of the fire extinguishing agent microcapsules to the inorganic binder is 1:4-8; and the drying temperature of the aerogel thermal insulation sheet is 20-150°C.

10. Use of the aerogel thermal insulation sheet according to any one of claims 1 to 4 or the aerogel thermal insulation sheet obtained by the preparation method according to any one of claims 5 to 9 in battery thermal runaway protection.

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