Rapid preparation method for composite thermal-runaway prevention material

Abstract

Disclosed in the present invention is a rapid preparation method for a composite thermal-runaway prevention material. The composite thermal-runaway prevention material comprises the following components, in percentages by mass: 71-95% of an inorganic heat-absorbing material, 0-5% of an inorganic light-guiding material, 0-12% of polyvinyl alcohol, 0-1% of a long-chain alkyl diacid and 5-16% of a UV-curable packaging resin. The preparation method therefor comprises: obtaining a fluffy mixture by using a mixing process, homogenizing same via a secondary homogenization device by means of a homogenizing process, the temperature of the mixture during the homogenization process being 0-80°C, and subjecting the uniform mixture to a forming process and a curing process, so as to obtain a composite thermal-runaway prevention material. A homogenizing process is added in the present invention, thereby improving the uniformity of powder spreading during the process of preparing a large-area and large-size composite thermal-runaway prevention material, and improving the strength of the composite thermal-runaway prevention material. The heat-absorption enthalpy value of the composite thermal-runaway prevention material is high, thereby preventing adjacent batteries from being continuously heated and avoiding fires and explosion; and the surface of the material is coated with a UV-curable packaging resin, thereby achieving stable packaging of the inorganic heat-absorbing material.

Description

A rapid preparation method for composite thermal runaway protection material Technical Field

[0001] The present invention belongs to the technical field of thermal runaway protection materials, and in particular relates to a method for rapidly preparing a composite thermal runaway protection material. Background Art

[0002] High-energy-density batteries, particularly lithium-ion batteries, have found widespread application in electric vehicles, portable electronic devices, and energy storage systems. However, as battery capacity and energy density increase, safety concerns are becoming increasingly prominent, particularly thermal runaway. Thermal runaway occurs when, under certain conditions, a battery's internal chemical reactions run wild, leading to a rapid temperature rise, potentially causing safety hazards such as fire or explosion. The main triggers are: internal short circuits: Internal short circuits due to mechanical or electrical abuse are common triggers of thermal runaway. Overcharging: Overcharging increases internal pressure in the battery, causing electrolyte decomposition and generating significant heat. High-temperature environments: Batteries exposed to high temperatures for extended periods are more susceptible to thermal runaway. Due to the rising cost of raw materials for lithium-ion batteries, sodium-ion batteries, as a new generation of power batteries with lower theoretical costs, have become a research hotspot. However, sodium-ion batteries also suffer from thermal runaway. This makes improving the safety of lithium / sodium batteries a key topic in battery research.

[0003] Existing thermal management solutions mainly use aerogel or insulation panels to separate each battery pack component. After a single battery pack experiences thermal runaway, the heat can be isolated within a limited range under non-serious conditions. However, aerogel cannot slow the progression of thermal runaway. Once thermal runaway occurs, there is still a possibility of spillover to adjacent battery packs, causing continued thermal runaway and resulting in fire or explosion.

[0004] Chinese patent CN202310479415.0 records a fast-absorbing thermal runaway protection material and its preparation method, which successfully applies chemical inorganic heat-absorbing materials to the thermal runaway diffusion of batteries. The preparation and molding process in the patent is room temperature curing for 24 hours, which has certain bottlenecks for the mass production of thermal runaway protection materials with rapid development needs. It is mainly manifested in low production efficiency and low packaging efficiency. During the production process, the thermal runaway protection material is filled into the shell, and it is difficult to ensure the density. In addition, the filling efficiency is extremely low, which is not suitable for large-scale production on the production line. How to effectively realize the rapid prototyping of thermal runaway protection materials and reduce manufacturing costs has become an urgent problem to be solved in the industrialization of thermal runaway protection materials.

[0005] Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a rapid preparation method of a composite thermal runaway protection material. In the preparation process, a secondary homogenization process is added to the primary mixing process to achieve rapid prototyping of the composite thermal runaway protection material. The composite thermal runaway protection material can be used in lithium-ion batteries and sodium-ion batteries. It can be designed according to different battery structures, conveniently placed between battery packs, or placed between a certain number of battery packs. The composite thermal runaway protection material of the present invention has a high endothermic enthalpy (the endothermic enthalpy of inorganic endothermic materials is greater than 1300 J / g). It will undergo a chemical reaction and actively absorb heat between 90 and 400°C. Usually, after thermal runaway, the battery pack will heat up rapidly, causing the composite thermal runaway protection material to reach above 90°C. At this time, the material will spontaneously endothermically decompose. Due to the high enthalpy of the material, a continuous endothermic effect is formed, which drives the temperature of the runaway battery pack to drop. Even after the material decomposes, the protection material will form a porous structure, becoming an excellent thermal insulation material, preventing heat from being transferred to adjacent batteries, preventing the adjacent batteries from continuing to heat up, and avoiding fire and explosion.

[0007] To achieve the above-mentioned object, the present invention adopts the following technical scheme: a method for rapidly preparing a composite thermal runaway protection material, the composite thermal runaway protection material comprising the following components by mass percentage: 71-95% inorganic heat-absorbing material, 0-5% inorganic light-guiding material, 0-12% polyvinyl alcohol, 0-1% long-chain alkyl diacid, and 5-16% UV-curable encapsulation resin;

[0008] The rapid preparation method of the composite thermal runaway protection material is as follows:

[0009] S1. obtaining a fluffy mixture by a mixing process;

[0010] S2. Through a homogenization process, the fluffy mixture is homogenized by a secondary homogenization device, the temperature of the mixture during the homogenization process is 0 to 80° C., and a uniform mixture is obtained;

[0011] S3. Performing a molding process and a curing process on the uniform mixture to obtain a composite thermal runaway protection material.

[0012] In the above technical solution, in step S1, the inorganic heat-absorbing material, the inorganic light-guiding material, the polyvinyl alcohol, the long-chain alkyl diacid and the UV-curing encapsulating resin are added to a mixing device and stirred while adding. The temperature of the mixture during the mixing process ranges from 0 to 80° C. The mixing time is greater than 10 minutes, and the mixture is vacuumed to remove bubbles to obtain a fluffy mixture.

[0013] The fluffy mixture has a specific gravity of less than 1 g / cm 3 ;

[0014] In step S3, the molding process is to add the uniform mixture into a mold and use a press to press to obtain a molding material, the molding temperature is 0 to 80° C., and the molding pressure is greater than 3 MPa;

[0015] In step S3, the curing process takes out the molding material and uses a UV lamp to cure it on one side or both sides. The curing starting material temperature is 0-60°C, and the maximum temperature of the material after curing does not exceed 80°C.

[0016] In the above technical solution, the method also includes a polishing process. In order to facilitate installation, the material after the curing process in step S3 is polished by a CNC machine tool to obtain a composite thermal runaway protection material with a smooth surface. The material temperature does not exceed 80°C during the polishing process.

[0017] In the above technical solution, in step S2, the secondary homogenization equipment includes any one of a three-roll mill, a calender, a sand mill, a roller press or a colloid mill.

[0018] Preferably, the primary mixing equipment includes any one of a reaction kettle, a dispersion kettle, a mixing kettle, a kneader, a planetary mixer or a gear pump with a buffer tank.

[0019] Preferably, the press comprises a four-column hydraulic press, a frame hydraulic press, an electric screw press or a precision servo press, preferably a press whose hydraulic speed and pressure lifting speed can be controlled by a computer.

[0020] Preferably, the mold is made of metal and is coated with Teflon on the surface, or an isolation film is placed on the upper and lower surfaces of the mold. Preferably, the isolation film includes PET release film, PP film, PTFE film, PE film, ETFE film or release paper. The mold is designed according to the model required by the customer to achieve high density and rapid shaping.

[0021] Preferably, the UV lamp is a high-pressure mercury lamp or a metal halide lamp, and preferably the UV lamp is a composite UV lamp composed of one or more UV LED lamps in the 365nm band, the 385nm band, the 395nm band, and the 405nm band. The installation form of the UV lamp includes single-sided installation, top and bottom aligned installation, or top and bottom staggered installation. The irradiation power received by the material surface is greater than 30mW / cm 2 , irradiation dose greater than 1J / cm 2 ; In the curing process, the curing depth can reach 40mm for double curing of the surface and bottom layers.

[0022] Preferably, the pressure applied by the press to the material is greater than 3 MPa, and the molding temperature is 0-80° C., preferably the mold is heated or the pressure plate of the press is heated.

[0023] In the above technical solution, the inorganic heat absorbing material includes sodium acetate trihydrate, ammonium ferric oxalate trihydrate, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, sodium carbonate decahydrate, calcium chloride hexahydrate, magnesium chloride hexahydrate, aluminum nitrate nonahydrate, ammonium pentaborate octahydrate, ammonium ferric sulfate dodecahydrate, ferrous chloride tetrahydrate, ammonium oxalate monohydrate, sodium tetraborate decahydrate, sodium tetraborate pentahydrate, aluminum sulfate 18hydrate, ammonium pentaborate, ammonium hydrogen borate tetrahydrate, boric acid, barium hydroxide octahydrate, sodium silicate pentahydrate, hydrated sodium aluminosilicate, silicic acid, and sodium hydroxide. , hydrated silicic acid, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate, copper sulfate heptahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, calcium sulfate dihydrate, etc., a mixture in any proportion; preferably, the inorganic endothermic material includes a mixture in any proportion of one or more of ammonium oxalate monohydrate, sodium acetate trihydrate, boric acid, ammonium pentaborate octahydrate, barium hydroxide octahydrate, sodium tetraborate decahydrate, potassium aluminum sulfate dodecahydrate, sodium sulfate decahydrate or calcium sulfate dihydrate, preferably with a mesh size of 80 to 300 meshes.

[0024] In the above technical solution, the inorganic light-guiding material is a material with transmittance to ultraviolet light, including a mixture of any one or more of spherical silicon powder, granular silicon powder, glass powder, quartz chopped fiber or glass chopped fiber in any proportion; preferably, the fiber diameter is 3 to 300 μm, the length is 0.5 to 5 mm, and the average particle size of the powder is preferably 80 to 300 mesh; the inorganic light-guiding material can enhance the overall strength of the thermal protection material, improve the high temperature resistance, and can also transmit the ultraviolet light on the surface to the deep layer, realizing dual curing of the surface and deep layer.

[0025] In the above technical solution, the long-chain alkyl diacid includes a mixture of any one or more of dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid or eicosanedioic acid in any proportion;

[0026] The polyvinyl alcohol is a powder, preferably with a mesh size of 80 to 300 meshes. The polyvinyl alcohol structure contains a large number of hydroxyl groups and has good water absorption. A small amount of water will be adsorbed on the powder surface. This water can undergo a hydrolysis reaction with the siloxane structure in the UV encapsulation resin to form a silanol structure, which then undergoes a condensation reaction with the hydroxyl group or crystal water on the surface of the inorganic heat-absorbing material, thereby enhancing the interfacial bonding strength between the encapsulation resin and the inorganic heat-absorbing material.

[0027] In the above technical solution, the composite thermal runaway protection material is cut into appropriate dimensions based on the battery pack's structure and encapsulated in a sealed, pressure-resistant casing. Depending on the application scenario of the energy storage battery, the thermal runaway protection material can be used as a standalone package or laminated with a thermal insulation buffer material to increase the thermal protection material's compression ratio and mitigate battery expansion and compression.

[0028] In the above technical solution, the composite thermal runaway protection material is used alone as a thermal runaway protection material, or is used in conjunction with a thermal insulation material or a physical insulation structure to form a thermal protection system. The composite thermal runaway protection material serves as a heat-absorbing material in the thermal protection system.

[0029] In the above technical solution, the UV curable encapsulation resin comprises, by mass percentage, 25-70% of silicone-epoxy resin composite modified polyurethane acrylate, 10-30% of silicone-polyurethane composite modified epoxy acrylate, 0-5% of epoxy resin, 5-40% of epoxy acrylate, 0-1% of acrylic acid, 5-30% of active monomer, 0-20% of silane modified resin, 0.1-3% of water scavenger, 0.1-3% of photoinitiator and 0.01-0.3% of polymerization inhibitor;

[0030] The preparation method of UV-curable encapsulation resin is as follows: add the silicone-epoxy resin composite modified polyurethane acrylate, silicone-polyurethane composite modified epoxy acrylate, epoxy resin, epoxy acrylate, acrylic acid, active monomer, silane-modified resin, photoinitiator and polymerization inhibitor in the above components into a reactor according to a proportion, maintain stirring at 50-60° C. for 2-3 hours, add a desiccant, and stir for 10-30 minutes to obtain UV-curable encapsulation resin.

[0031] In the above technical solution, the epoxy resin refers to a substance containing an epoxy bond in its molecular structure, including a mixture of any one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E epoxy resin, bisphenol S epoxy resin, epoxy soybean oil, cardanol-modified epoxy resin, trimethylolpropane triglycidyl ether, hexanediol diglycidyl ether or phenyl glycidyl ether in any proportion;

[0032] The epoxy acrylate is a product obtained by mixing acrylic acid and carboxyethyl acrylate in any proportion and ring-opening the mixture with the above-mentioned epoxy resin, including CN104NS or CN120NS of Sartomer;

[0033] The reactive monomer is an acrylate monomer with 1-6 functional groups and does not contain a hydroxyl structure, including a mixture of any one or more of isobornyl acrylate, 2-cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, isobornyl methacrylate, or tetrahydrofurfuryl methacrylate in any proportion;

[0034] The silane-modified resin is a resin terminated with an alkoxysilyl group, including a mixture of any one or more of a silane-modified polyether resin, a silane-modified polyacrylate resin, a silane-modified polyurethane resin, a silane-modified polyester resin or an alkoxy silicone resin in any proportion; preferably, the alkoxysilane group includes trimethoxysilane, triethoxysilane, methyldimethoxysilane or methyldiethoxysilane;

[0035] The dehydrating agent is p-toluenesulfonyl isocyanate, which can effectively remove residual moisture in the system, prevent the hydrolysis of siloxane on the siloxane-epoxy resin composite modified polyurethane acrylate structure, and improve the storage stability of the UV curing encapsulation resin;

[0036] The photoinitiator is a substance that can decompose or abstract hydrogen to generate free radicals under ultraviolet light irradiation, including a mixture of any one or more of 4-benzoyl-4'-methyl-diphenyl sulfide (BMS), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphosphonic acid ethyl ester (TPO-L), bis(2,4,6-trimethylbenzyl)phenylphosphine oxide (819), benzoin dimethyl ether (651), 2-methyl-1-(4-methylmercaptophenyl)-2-morpholine-1-propanone (907), 1-hydroxycyclohexyl benzophenone (184), 4-acryloyloxybenzophenone or methyl o-benzoylbenzoate (OMBB) in any proportion. Under ultraviolet light irradiation, the surface of the material will quickly solidify and form a material with a certain strength, which is conducive to subsequent transportation.

[0037] In the above technical solution, the preparation method of the silicone-epoxy resin composite modified polyurethane acrylate is as follows:

[0038] A1. Add diisocyanate and hydroxy acrylate in a molar ratio of 1:1 to reactor A, add 0.01-0.2% of the total mass of the diisocyanate and hydroxy acrylate as a catalyst dibutyltin dilaurate, and 0.01-0.2% of the total mass of the diisocyanate and hydroxy acrylate as a polymerization inhibitor p-hydroxyanisole, raise the temperature to 40-60° C. and react for 1-3 hours to obtain a semi-adduct of diisocyanate and hydroxyethyl acrylate, and calculate the theoretical NCO equivalent;

[0039] A2. Add epoxy resin and mercaptosilane coupling agent to reactor B in a molar ratio of epoxy bond to mercapto group of 1:1, add 0.01-0.2% of the total mass of triethylamine as a catalyst, raise the temperature to 70-90° C., react for 1-3 hours to obtain siloxane-modified epoxy resin, and calculate the theoretical hydroxyl equivalent;

[0040] A3. According to the calculation method of NCO equivalent: hydroxyl equivalent = mass of semi-adduct: mass of siloxane-modified epoxy resin, a set amount of siloxane-modified epoxy resin was added to reactor A. 0.01-0.2% of the total mass of the siloxane-modified epoxy resin was added as a catalyst, dibutyltin dilaurate, and 0.01-0.2% of the total mass of the siloxane-modified epoxy resin was added as a polymerization inhibitor, p-hydroxyanisole. The reaction was stirred at 60-80°C for 2-8 hours. The infrared spectrometer was used to detect the wavelength at 2260 cm -1 After the isocyanate absorption peak disappears, the silicone-epoxy resin composite modified polyurethane acrylate is obtained.

[0041] Furthermore, in step A1, 0 to 30% by weight of a 1-6-functional acrylate monomer without a hydroxyl structure is added to the total weight of the diisocyanate and the hydroxy acrylate; in step A2, 0 to 30% by weight of a 1-6-functional acrylate monomer without a hydroxyl structure is added to the total weight of the epoxy resin and the mercaptosilane coupling agent;

[0042] Alternatively, in step A1, 0-30% by weight of the total mass of the diisocyanate and the hydroxy acrylate in an amount of a 1-6-functional acrylate monomer that does not contain a hydroxyl structure is added; in step A3, 0-30% by weight of the total mass of the siloxane-modified epoxy resin in an amount of a 1-6-functional acrylate monomer that does not contain a hydroxyl structure is added;

[0043] Alternatively, in step A2, 0-30% of the total mass of the epoxy resin and the mercaptosilane coupling agent is added to a 1-6-functional acrylate monomer that does not contain a hydroxyl structure; in step A3, 0-30% of the total mass of the siloxane-modified epoxy resin is added to a 1-6-functional acrylate monomer that does not contain a hydroxyl structure;

[0044] Alternatively, in step A1, 0-30% by weight of a 1-6-functional acrylate monomer without a hydroxyl structure is added to the total weight of the diisocyanate and the hydroxy acrylate; in step A2, 0-30% by weight of a 1-6-functional acrylate monomer without a hydroxyl structure is added to the total weight of the epoxy resin and the mercaptosilane coupling agent; and in step A3, 0-30% by weight of a 1-6-functional acrylate monomer without a hydroxyl structure is added to the total weight of the siloxane-modified epoxy resin.

[0045] Furthermore, in step A1, 0 to 30% by weight of the total weight of the diisocyanate and the hydroxy acrylate and a 1-6 functional acrylate monomer that does not contain a hydroxyl structure is added;

[0046] Or in step A2, 0 to 30% of the total mass of the epoxy resin and the mercaptosilane coupling agent is added to a 1-6 functional acrylate monomer that does not contain a hydroxyl structure;

[0047] Alternatively, in step A3, 0 to 30% of the total mass of the silicone-modified epoxy resin is added with a 1-6 functional acrylate monomer that does not contain a hydroxyl structure.

[0048] Specifically, the acrylate monomer includes a mixture of any one or more of isobornyl acrylate, 2-cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, isobornyl methacrylate or tetrahydrofurfuryl methacrylate in any proportion.

[0049] Specifically, in step A1, the diisocyanate includes any one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (including T100 / T80 / T65), xylylene diisocyanate (XDI), trimethylol hexamethylene diisocyanate (TMDI), 1,5-naphthalene diisocyanate (NDI) or diphenylmethane diisocyanate (MDI-100 / MDI-50) in any proportion;

[0050] In step A1, the hydroxy acrylate includes a mixture of any one or more of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxybutyl acrylate or 4-hydroxybutyl acrylate in any proportion;

[0051] In step A2, the epoxy resin refers to a substance containing an epoxy bond in its molecular structure, including a mixture of any one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E epoxy resin, bisphenol S epoxy resin, epoxidized soybean oil, cardanol-modified epoxy resin, trimethylolpropane triglycidyl ether, hexanediol diglycidyl ether, or phenyl glycidyl ether in any proportion;

[0052] In step A2, the mercaptosilane coupling agent includes a mixture of any one or more of mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptopropylmethyldimethoxysilane or mercaptopropylmethyldiethoxysilane in any proportion.

[0053] In the above technical solution, the preparation method of the silicone-polyurethane composite modified epoxy acrylate is as follows:

[0054] B1. Add diisocyanate and mercaptosilane coupling agent in a molar ratio of 1:1 into reactor C, add 0.01-0.2% of the total mass of diisocyanate and mercaptosilane coupling agent as a catalyst dibutyltin dilaurate, raise the temperature to 70-100° C. and react for 4-8 hours to obtain a semi-adduct of diisocyanate and mercaptosilane coupling agent;

[0055] B2. Add diisocyanate and epoxy acrylate in a molar ratio of 1:1 to 1:0.5, add a set mass of epoxy acrylate to reactor C, add 0.01 to 0.2% of the total mass of epoxy acrylate as a catalyst dibutyltin dilaurate, maintain the temperature at 70 to 90° C. and react for 1 to 3 hours to obtain siloxane-polyurethane composite modified epoxy acrylate.

[0056] Furthermore, in step B1, 0 to 30% of the total mass of diisocyanate and mercaptosilane coupling agent is added to a 1-6 functional acrylate monomer that does not contain a hydroxyl structure; in step B2, 0 to 30% of the total mass of epoxy acrylate is added to a 1-6 functional acrylate monomer that does not contain a hydroxyl structure.

[0057] Furthermore, in step B1, 0 to 30% of the total mass of the diisocyanate and the mercaptosilane coupling agent is added to a 1-6 functional acrylate monomer that does not contain a hydroxyl structure;

[0058] Alternatively, in step B2, 0 to 30% by weight of the total epoxy acrylate weight is added to a 1-6 functional acrylate monomer that does not contain a hydroxyl structure.

[0059] Specifically, the acrylate monomer includes a mixture of any one or more of isobornyl acrylate, 2-cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, isobornyl methacrylate or tetrahydrofurfuryl methacrylate in any proportion.

[0060] Specifically, in step B1 or B2, the diisocyanate includes any one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (including T100 / T80 / T65), xylylene diisocyanate (XDI), trimethylol hexylene diisocyanate (TMDI), 1,5-naphthalene diisocyanate (NDI) or diphenylmethane diisocyanate (MDI-100 / MDI-50) in any proportion;

[0061] In step B1, the mercaptosilane coupling agent includes a mixture of any one or more of mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptopropylmethyldimethoxysilane or mercaptopropylmethyldiethoxysilane in any proportion.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. The composite thermal runaway protection material molding process described in the present invention adds a secondary homogenization process on the basis of a primary mixing process, thereby improving the uniformity of the encapsulation resin and the powder, improving the uniformity of the powder spreading during the preparation of large-area and large-size composite thermal runaway protection materials, and improving the strength of the composite thermal runaway protection materials.

[0064] 2. The composite thermal runaway protection material described in the present invention is an organic-inorganic composite material. A UV-curing encapsulation resin is coated on the surface of the inorganic heat-absorbing material, thereby achieving stable encapsulation of the inorganic heat-absorbing material. Moreover, after being irradiated with ultraviolet light, the inorganic light-guiding material can guide the ultraviolet light into the deep layer, thereby achieving dual curing of the surface and deep layer, thereby meeting the one-time curing and molding requirements for a 40mm thick composite thermal runaway protection material.

[0065] 3. The composite thermal runaway protection material of the present invention has a high endothermic enthalpy value, and after the inorganic endothermic material is decomposed, the protection material will form a porous structure, becoming an excellent thermal insulation material, preventing heat from being transferred to adjacent batteries, preventing adjacent batteries from continuing to heat up, and avoiding fire and explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The present invention will be further described below with reference to the accompanying drawings and examples:

[0067] FIG1 is a schematic diagram of a rapid preparation process of a composite thermal runaway protection material according to the present invention;

[0068] FIG2 is a schematic diagram of the curing process of the composite thermal runaway protection material of the present invention;

[0069] In the figure: inorganic heat absorbing material 1; inorganic light guiding material 2; polyvinyl alcohol 3; inorganic light guiding material light transmission 4; UV curing encapsulant (before curing) 5; UV curing encapsulant (after curing) 6;

[0070] FIG3 is a schematic diagram of the endothermic decomposition process of the composite thermal runaway protection material of the present invention;

[0071] In the figure: inorganic heat-absorbing material 1; inorganic heat-absorbing material decomposition residue 2; polyvinyl alcohol 3; UV curing encapsulant (after curing) 4; inorganic light-guiding material 5; pores formed after decomposition of the inorganic heat-absorbing material 6;

[0072] FIG4 is a schematic diagram of the test device of the present invention. DETAILED DESCRIPTION

[0073] In order to better understand the present invention, the present invention is further described below through specific embodiments, but it is not intended to limit the present invention.

[0074] Figure 1 is a flow chart of the rapid preparation process for a composite thermal runaway protection material according to the present invention. Inorganic heat-absorbing material, inorganic light-guiding material, polyvinyl alcohol, long-chain alkyl diacid, and UV-curable encapsulating resin are mixed, homogenized, molded, cured, and polished to produce the composite thermal runaway protection material. The homogenization process is added to the mixing process during the preparation process to achieve rapid prototyping of the composite thermal runaway protection material.

[0075] Figure 2 shows the curing process of the composite thermal runaway protection material of the present invention. The surface of the composite thermal runaway protection material is coated with UV curing encapsulation resin. After irradiation with ultraviolet light, the inorganic light-guiding material inside the adhesive resin guides the ultraviolet light into the deep layer, realizing one-time curing and molding.

[0076] Figure 3 is an endothermic decomposition diagram of the composite thermal runaway protection material of the present invention. The endothermic enthalpy of the composite thermal runaway protection material is high (the endothermic enthalpy of inorganic endothermic materials is >1200 J / g). After the thermal runaway of the battery pack, the temperature rises rapidly, so that the composite thermal runaway protection material reaches above 90°C. At this time, the material will spontaneously endothermically decompose, forming a continuous endothermic effect, driving the temperature of the runaway battery pack to drop. After the decomposition of the protective material is completed, a porous structure will be formed on the surface of the material, becoming an excellent thermal insulation material to prevent heat transfer and avoid fire and explosion of the battery pack.

[0077] Some of the special raw materials used in the following examples are shown in Table 1.

[0078] Table 1

[0079] The silicone-epoxy resin composite modified polyurethane acrylate and silicone-polyurethane composite modified epoxy acrylate used in the present invention are specifically prepared as follows:

[0080] 1. Preparation of siloxane-epoxy resin composite modified polyurethane acrylate:

[0081] A1: 444.58 g (2 mol) of isophorone diisocyanate, 236.98 g (2 mol, 98% purity) of 2-hydroxyethyl acrylate, 0.4 g of a catalyst (dibutyltin dilaurate), and 0.5 g of a polymerization inhibitor (p-hydroxyanisole) were added to reactor A, and the temperature was raised to 40-45° C. for reaction for 3 hours to obtain a semi-adduct of diisocyanate and hydroxyethyl acrylate, with a calculated theoretical NCO equivalent weight of 341.23 g / mol.

[0082] A2: Add 510 g (1.5 mol of epoxy resin, 3 mol of epoxy bonds) of bisphenol F epoxy resin, 841.11 g (3 mol) of mercaptopropyltriethoxysilane, and 1.35 g of catalyst (triethylamine) to another reactor B. Heat to 85° C. and react for 2.5 hours to obtain a siloxane-modified epoxy resin, which is set aside. The calculated theoretical hydroxyl equivalent weight is 450.82 g / mol.

[0083] A3: According to the calculation method of NCO equivalent: hydroxyl equivalent = mass of semi-adduct: mass of siloxane-modified epoxy resin, there are 682.46g of semi-adduct in reactor A. Add 901.64g of siloxane-modified epoxy resin to reactor A, add 180g of 1,6-hexanediol diacrylate, 0.7g of catalyst (dibutyltin dilaurate) and 0.9g of inhibitor (p-hydroxyanisole), maintain stirring at 70-75℃ for 4 hours, and use infrared spectrometer to detect the color at 2260cm -1 After the isocyanate absorption peaks around 50°C disappear, the siloxane-epoxy resin composite modified polyurethane acrylate Si / EP-PUA1 is obtained.

[0084] 2. Preparation of Siloxane-Polyurethane Composite Modified Epoxy Acrylate:

[0085] B1: 222.29 g (1 mol) of isophorone diisocyanate, 280.37 g (1 mol) of mercaptopropyltriethoxysilane, and 0.4 g of catalyst (dibutyltin dilaurate) were added to reactor C, and the temperature was raised to 70-80° C. for reaction for 5-6 hours to obtain a semi-adduct of diisocyanate and mercaptosilane coupling agent;

[0086] B2: Add 350 g of epoxy acrylate (CN104NS) and 0.3 g of catalyst (dibutyltin dilaurate) in a molar ratio of diisocyanate to epoxy acrylate of 1:0.7 to reactor C, maintain the temperature at 80-90°C for 2-2.5 hours to obtain the silicone-polyurethane composite modified epoxy acrylate Si / PUA-EP1.

[0087] Example 1:

[0088] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 40% hydrated silicic acid, 45% magnesium chloride hexahydrate, 5% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 9.7% UV-curable encapsulating resin UV-3. The preparation method is as follows:

[0089] S1 mixing process: 400g of hydrated silicic acid, 450g of magnesium chloride hexahydrate, 50g of polyvinyl alcohol, 3g of hexadecanedioic acid, and 97g of UV curing encapsulation resin UV-3 are added to a primary mixing kettle while stirring. The temperature of the mixture during the mixing process is in the range of 20-30°C and the mixing time is 15 minutes. Vacuum the mixture to remove bubbles and obtain a fluffy mixture;

[0090] S2 homogenization process: The mixture obtained by the primary mixing equipment is homogenized by a three-roller mill. The temperature of the mixture during the homogenization process ranges from 20 to 30°C to obtain a uniform mixture.

[0091] S3 molding process: The uniform mixture was added to a 227mm×160mm×2mm mold with a polytetrafluoroethylene coating on the surface. The mold was pressed into shape under a hydraulic press. The feed weight was 116.3g, the molding temperature was 35±5℃, and the molding pressure was 8.7MPa.

[0092] S3 curing process: Take out the pressed material and place it under 100mW / cm 2 Irradiation under a metal halide lamp for 40 seconds, the irradiation dose is 4J / cm 2 The starting temperature of the curing material is 30-35°C, and the maximum temperature after curing is 60°C.

[0093] S3 polishing process: To facilitate installation, the cured material can be polished by CNC (numerical control machine) to obtain a composite thermal runaway protection material R-2 with a smooth surface. The maximum temperature of the material during the polishing process is 45°C.

[0094] The UV curing encapsulation resin UV-3 comprises the following components by mass percentage: 144.4% of silicone-epoxy resin composite modified polyurethane acrylate Si / EP-PUA, 125% of silicone-polyurethane composite modified epoxy acrylate Si / PUA-EP, 1% of bisphenol A epoxy resin, 15% of epoxy acrylate, 1% of acrylic acid, 10% of active monomer (dipropylene glycol diacrylate), 0.5% of p-toluenesulfonyl isocyanate, 1% of photoinitiator (184), 1% of 4-acryloyloxybenzophenone, 1% of photoinitiator (TPO), and 0.1% of polymerization inhibitor (p-hydroxyanisole);

[0095] The preparation method is as follows: 444g of silicone-epoxy resin composite modified polyurethane acrylate Si / EP-PUA1, 250g of silicone-polyurethane composite modified epoxy acrylate Si / PUA-EP1, 10g of bisphenol A epoxy resin, 150g of epoxy acrylate (CN120NS), 10g of acrylic acid, 100g of active monomer (dipropylene glycol diacrylate), 10g of photoinitiator (184), 10g of 4-acryloyloxybenzophenone, 10g of photoinitiator (TPO), and 1g of inhibitor (p-hydroxyanisole) are added into a reactor, the mixture is stirred at 55°C for 2.5 hours, 5g of p-toluenesulfonyl isocyanate is added, and the mixture is stirred for 20 minutes to obtain a UV-curable encapsulation resin UV-3.

[0096] The thermal conductivity, enthalpy, density, average thickness and compressive strength of the composite thermal runaway protection material R-2 prepared in this embodiment are shown in Table 2.

[0097] Example 2:

[0098] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 88% potassium aluminum sulfate dodecahydrate, 2% quartz chopped fiber, 2% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 7.7% UV-curable encapsulating resin UV-4. The preparation method is as follows:

[0099] S1 mixing process: 880g of potassium aluminum sulfate dodecahydrate, 20g of quartz chopped fiber, 20g of polyvinyl alcohol, 3g of hexadecanedioic acid, and 77g of UV-curable encapsulation resin UV-4 are added to a primary mixing kettle while stirring. The temperature of the mixture during the mixing process is in the range of 30-35°C and the mixing time is 25 minutes. Vacuum is applied to remove bubbles to obtain a fluffy mixture;

[0100] S2 homogenization process: The mixture obtained by the primary mixing equipment is homogenized by a calender. The temperature of the mixture during the homogenization process is in the range of 40-45°C to obtain a uniform mixture.

[0101] S3 molding process: The uniform mixture was added to a 227mm×160mm×10mm mold with a polytetrafluoroethylene coating on the surface, and the mold was pressed under a hydraulic press. The feed weight was 581.5g, the molding temperature was 40±5℃, and the molding pressure was 10MPa.

[0102] S3 curing process: Take out the pressed material and place it under 100mW / cm 2 Irradiation under a metal halide lamp for 60 seconds, the irradiation dose is 6J / cm 2 The starting temperature of the curing material is 30-35°C, and the maximum temperature after curing is 68°C.

[0103] S3 polishing process: To facilitate installation, the cured material can be polished by CNC (numerical control) machine to obtain a composite thermal runaway protection material R-10 with a smooth surface. The maximum temperature of the material during the polishing process is 40°C.

[0104] The UV curing encapsulation resin UV-4 comprises the following components by mass percentage: 141.6% of silicone-epoxy resin composite modified polyurethane acrylate Si / EP-PUA, 15% of silicone-polyurethane composite modified epoxy acrylate Si / PUA-EP, 18.3% of epoxy acrylate, 9% of active monomer (trimethylolpropane triacrylate), 12% of active monomer (tripropylene glycol diacrylate), 1% of p-toluenesulfonyl isocyanate, 0.5% of photoinitiator (184), 1% of 4-acryloyloxybenzophenone, 1.5% of photoinitiator (TPO), and 0.1% of polymerization inhibitor (p-hydroxyanisole); and its preparation method is the same as that of the UV curing encapsulation resin UV-3 in Example 1.

[0105] The thermal conductivity, enthalpy, density, average thickness and compressive strength of the composite thermal runaway protection material R-10 prepared in this example are shown in Table 2.

[0106] Example 3:

[0107] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 40% potassium aluminum sulfate dodecahydrate, 46.4% magnesium chloride hexahydrate, 1% quartz chopped fiber, 1% silica powder, 1% polyvinyl alcohol, 0.6% eicosanedioic acid, and 10% UV-curable encapsulating resin UV-4. The preparation method is as follows:

[0108] S1 mixing process: 800g of potassium aluminum sulfate dodecahydrate, 928g of magnesium chloride hexahydrate, 20g of quartz chopped fiber, 20g of silica powder, 20g of polyvinyl alcohol, 12g of eicosanedioic acid, and 200g of UV-curable encapsulation resin UV-4 are added to a primary mixing kettle while stirring. The temperature of the mixture during the mixing process is in the range of 30-35°C, and the mixing time is 25 minutes. Vacuum is then applied to remove bubbles to obtain a fluffy mixture.

[0109] S2 homogenization process: The mixture obtained by the primary mixing equipment is homogenized by a colloid mill. The temperature of the mixture during the homogenization process is in the range of 40-45°C to obtain a uniform mixture.

[0110] S3 molding process: The uniform mixture was added to a 227mm×160mm×30mm mold with a polytetrafluoroethylene coating on the surface. The mold was pressed into shape using a hydraulic press. The feed weight was 1741.4g, the molding temperature was 45±5℃, and the molding pressure was 9.5MPa.

[0111] S3 curing process: Take out the pressed material and place it under 100mW / cm 2 The front and back surfaces were irradiated for 80 seconds under a metal halide lamp, and the irradiation dose for each surface was 8J / cm 2 The starting temperature of the curing material is 30-35°C, and the maximum temperature after curing is 71°C.

[0112] S3 polishing process: To facilitate installation, the cured material can be polished by CNC (numerical control) machine to obtain a composite thermal runaway protection material R-30 with a smooth surface. The maximum temperature of the material during the polishing process is 46°C.

[0113] The UV curing encapsulation resin UV-4 and its preparation method are the same as those in Example 2.

[0114] The thermal conductivity, enthalpy, density, average thickness and compressive strength of the composite thermal runaway protection material R-30 prepared in this embodiment are shown in Table 2.

[0115] Example 4:

[0116] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 87% magnesium chloride hexahydrate, 5% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 7.7% UV-curable encapsulating resin UV-3. The preparation method is as follows:

[0117] S1 mixing process: 870g of magnesium chloride hexahydrate, 50g of polyvinyl alcohol, 3g of hexadecanedioic acid, and 77g of UV curing encapsulation resin UV-3 are added to a primary mixing kettle while stirring. The temperature of the mixture during the mixing process is in the range of 20-30°C and the mixing time is 15 minutes. Vacuum the mixture to remove bubbles and obtain a fluffy mixture;

[0118] S2 homogenization process: The mixture obtained by the primary mixing equipment is homogenized by a three-roller mill. The temperature of the mixture during the homogenization process ranges from 20 to 30°C to obtain a uniform mixture.

[0119] S3 molding process: The uniform mixture was added to a 227mm×160mm×2mm mold with a polytetrafluoroethylene coating on the surface, and the mold was pressed under a hydraulic press. The feed weight was 117.1g, the molding temperature was 35±5℃, and the molding pressure was 10.5MPa;

[0120] S3 curing process: Take out the pressed material and place it under 100mW / cm 2 Irradiation under a metal halide lamp for 40 seconds, the irradiation dose is 4J / cm 2 The starting temperature of the curing material is 30-35°C, and the maximum temperature after curing is 62°C.

[0121] S3 polishing process: To facilitate installation, the cured material can be polished by CNC (numerical control) machine to obtain a composite thermal runaway protection material S-2 with a smooth surface. The maximum temperature of the material during the polishing process is 48°C.

[0122] The UV curing encapsulation resin UV-3 and its preparation method are the same as those in Example 1.

[0123] Example 4 is based on Example 1, and some components and their mass percentages are changed. The thermal conductivity, enthalpy value, density, average thickness and compressive strength of the composite thermal runaway protection material S-2 prepared in this example are measured and shown in Table 2.

[0124] Example 5:

[0125] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 85% potassium aluminum sulfate dodecahydrate, 2% spherical silicon powder, 3% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 9.7% UV-curable encapsulating resin UV-4. The preparation method is as follows:

[0126] S1 mixing process: 850g of potassium aluminum sulfate dodecahydrate, 20g of spherical silica powder, 30g of polyvinyl alcohol, 3g of hexadecanedioic acid, and 97g of UV-curable encapsulation resin UV-4 are added to a primary mixing kettle while stirring. The temperature of the mixture during the mixing process is in the range of 30-35°C and the mixing time is 25 minutes. Vacuum the mixture to remove bubbles and obtain a fluffy mixture;

[0127] S2 homogenization process: The mixture obtained by the primary mixing equipment is homogenized by a calender. The temperature of the mixture during the homogenization process is in the range of 40-45°C to obtain a uniform mixture.

[0128] S3 molding process: The uniform mixture was added to a 227mm×160mm×10mm mold with a polytetrafluoroethylene coating on the surface, and the mold was pressed under a hydraulic press. The feed weight was 585.4g, the molding temperature was 40±5℃, and the molding pressure was 9.5MPa;

[0129] S3 curing process: Take out the pressed material and place it under 100mW / cm 2 Irradiation under a metal halide lamp for 60 seconds, the irradiation dose is 6J / cm 2 The starting temperature of the curing material is 30-35°C, and the maximum temperature after curing is 70°C.

[0130] S3 polishing process: To facilitate installation, the cured material can be polished by CNC (numerical control) machine to obtain a composite thermal runaway protection material S-10 with a smooth surface. The maximum temperature of the material during the polishing process is 45°C.

[0131] The UV curing encapsulation resin UV-4 and its preparation method are the same as those in Example 2.

[0132] Example 5 is based on Example 2, and some components and their mass percentages are changed. The thermal conductivity, enthalpy value, density, average thickness and compressive strength of the composite thermal runaway protection material S-10 prepared in this example are measured and shown in Table 2.

[0133] Example 6:

[0134] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 26.4% potassium aluminum sulfate dodecahydrate, 60% magnesium chloride hexahydrate, 1% quartz chopped fiber, 1% silica powder, 1% polyvinyl alcohol, 0.6% eicosanedioic acid, and 10% UV-curable encapsulating resin UV-4. The preparation method is as follows:

[0135] S1 mixing process: 528g of potassium aluminum sulfate dodecahydrate, 1200g of magnesium chloride hexahydrate, 20g of quartz chopped fiber, 20g of silica powder, 20g of polyvinyl alcohol, 12g of eicosanedioic acid, and 200g of UV-curable encapsulation resin UV-4 are added to a primary mixing kettle while stirring. The temperature of the mixture during the mixing process is in the range of 30-35°C, and the mixing time is 25 minutes. Vacuum is then applied to remove bubbles to obtain a fluffy mixture.

[0136] S2 homogenization process: The mixture obtained by the primary mixing equipment is homogenized by a colloid mill. The temperature of the mixture during the homogenization process is in the range of 40-45°C to obtain a uniform mixture.

[0137] S3 molding process: The uniform mixture was added to a 227mm×160mm×30mm mold with a polytetrafluoroethylene coating on the surface, and the mold was pressed into shape using a hydraulic press. The feed weight was 1762.2g, the molding temperature was 45±5℃, and the molding pressure was 10.2MPa.

[0138] S3 curing process: Take out the pressed material and place it under 100mW / cm 2 The front and back surfaces were irradiated for 80 seconds under a metal halide lamp, and the irradiation dose for each surface was 8J / cm 2 The starting temperature of the curing material is 30-35°C, and the maximum temperature after curing is 70°C.

[0139] S3 polishing process: To facilitate installation, the cured material can be polished by CNC (numerical control) machine to obtain a composite thermal runaway protection material S-30 with a smooth surface. The maximum temperature of the material during the polishing process is 48°C.

[0140] The UV curing encapsulation resin UV-4 and its preparation method are the same as those in Example 2.

[0141] Example 6 is based on Example 3, and some components and their mass percentages are changed. The thermal conductivity, enthalpy value, density, average thickness and compressive strength of the composite thermal runaway protection material S-30 prepared in this example are measured and shown in Table 2.

[0142] Comparative Example 1:

[0143] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 40% hydrated silicic acid, 34.7% magnesium chloride hexahydrate, 5% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 20% UV-3 curing encapsulating resin. The preparation method, feed weight and pressure, and radiation dose are the same as those in Example 1.

[0144] The UV curing encapsulation resin UV-3 and its preparation method are the same as those in Example 1.

[0145] Comparative Example 1 is based on Example 1, and the mass percentages of some components are changed, wherein the content of UV-curable encapsulation resin UV-3 exceeds the protection scope of the present invention. The thermal conductivity, enthalpy value, density, average thickness and compressive strength of the composite thermal runaway protection material D-A2 prepared in this comparative example are shown in Table 2.

[0146] Comparative Example 2:

[0147] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 48% hydrated silicic acid, 45% magnesium chloride hexahydrate, 5% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 1.7% UV-curable encapsulating resin UV-3. The preparation method, feed weight and pressure, and radiation dose are the same as those in Example 1.

[0148] The UV curing encapsulation resin UV-3 and its preparation method are the same as those in Example 1.

[0149] Comparative Example 2 is based on Example 1, but the mass percentages of some components are changed. In Comparative Example 2, the UV-3 content of the UV-curing encapsulation resin is too low, and it was found during implementation that molding could not be performed.

[0150] Comparative Example 3:

[0151] A method for rapidly preparing a composite thermal runaway protection material. The composite thermal runaway protection material comprises, by mass percentage, 40% hydrated silicic acid, 45% magnesium chloride hexahydrate, 5% polyvinyl alcohol, 0.3% hexadecanedioic acid, and 9.7% UV-curable encapsulating resin UV-5. The preparation method, feed weight and pressure, and radiation dose are the same as those in Example 1.

[0152] The UV-curable encapsulation resin UV-5 comprises the following components by mass percentage: 9.4% of polyurethane acrylate Changxing 6148-J756, 1% of bisphenol A epoxy resin, 15% of epoxy acrylate, 1% of acrylic acid, 10% of active monomer (dipropylene glycol diacrylate), 0.5% of p-toluenesulfonyl isocyanate, 1% of photoinitiator (184), 1% of 4-acryloyloxybenzophenone, 1% of photoinitiator (TPO), and 0.1% of polymerization inhibitor (p-hydroxyanisole); and its preparation method is the same as that of the UV-curable encapsulation resin UV-3 in Example 1.

[0153] Comparative Example 3 is based on Example 1, except that the UV-curable encapsulation resin UV-3 is replaced by the UV-curable encapsulation resin UV-5, and the silicone-epoxy resin composite modified polyurethane acrylate Si / EP-PUA1 and silicone-polyurethane composite modified epoxy acrylate Si / PUA-EP1 in this example are not used. The thermal conductivity, enthalpy value, density, average thickness and compressive strength of the composite thermal runaway protection material D-C2 prepared in this comparative example are shown in Table 2.

[0154] Performance tests were conducted on Examples 1 to 6 and Comparative Examples 1 to 3, and the results are shown in Table 2.

[0155] Table 2 Performance test of the embodiment Note: ① Thermal conductivity refers to ISO22007-2 test;

[0156] ② Differential scanning calorimetry test;

[0157] ③ Density = weight / volume;

[0158] ④Compression strength refers to GB / T1041-2008 test.

[0159] The enthalpy values ​​prepared in Comparative Example 1 were all lower than those in Examples 1-6, failing to meet the rapid heat absorption requirements during battery thermal runaway. The UV-curable encapsulation resin content in Comparative Example 2 was too low, making the prepared thermal protection material impossible to form. The UV-curable encapsulation resin in Comparative Example 3, which did not utilize silicone-epoxy composite-modified polyurethane acrylate and silicone-polyurethane composite-modified epoxy acrylate, exhibited poor adhesion to the heat-absorbing material, resulting in low compressive strength for the prepared material.

[0160] Test example:

[0161] In order to test the thermal runaway effect of the composite thermal runaway protective material of the present invention, a test platform was built. Two soft-pack lithium iron phosphate batteries with an outer dimension of 227x160x7.25mm, a standard voltage of 3.3V, and a fully charged capacity of 20AH are numbered 1 and 2 respectively. The composite thermal runaway protective material prepared in the embodiment and the comparative example is sandwiched between battery No. 1 and battery No. 2. A heating plate with a power of 500W is attached to the right side of battery No. 1 and fixed with two upper and lower fixing fixtures. The two batteries are connected to a signal acquisition device to collect the voltage of the two batteries and the temperature of the bonding surface of the two batteries and the composite thermal runaway protective material. A blank sample without the composite thermal runaway protective material and a sample of 2mm glass fiber aerogel are also made. Its structure is shown in Figure 4.

[0162] The test steps are as follows: Place the heating plate and battery pack in an oven at 50±2°C for 12 hours. Power the heating plate and set the heating plate power to 100% while collecting battery voltage and temperature. When the voltage of battery No. 1 reaches 0V, stop heating and continue collecting battery temperature until the temperatures of both batteries drop below 50°C. Data collection stops at this point. The results are shown in Table 3.

[0163] Table 3 Application test of Examples 1 to 3 and Comparative Examples 1 to 3

[0164] The test showed that the blank sample, which did not use the composite thermal runaway protection material, went into complete thermal runaway when heated on a heating plate. The maximum temperature of the battery reached 385°C, and the adjacent battery No. 2 also experienced thermal runaway. Due to the thermal insulation effect of the aerogel, the internal temperature of battery No. 1 in the sample using aerogel increased faster, leading to complete thermal runaway of the 196S battery, which reached a maximum temperature of 475°C, 90°C higher than the blank sample. The adjacent battery No. 2 also experienced thermal runaway.

[0165] In the test using the 2mm composite thermal runaway protection material R-2 of the present invention, the adjacent battery No. 2 did not experience thermal runaway, and the time for the voltage of battery No. 1 to drop to 0 was nearly twice as long as the heating time of the blank sample. The maximum temperature of the battery during the entire test process was 272°C, which was more than 100°C lower than the temperature of the blank sample. The thermal conductivity of the composite thermal runaway protection material after the test was 0.072W / (mK), which has a good heat insulation effect. The maximum temperature of the adjacent battery No. 2 was 119°C. This is lower than the thermal runaway temperature of lithium iron phosphate batteries reported in the literature of 150°C (Mei Wenxin, et al. Simulation study on high-temperature thermal runaway of large lithium iron phosphate batteries [J]. Energy Storage Science and Technology, 2021, 10(1): 202-209).

[0166] In the test using the 10mm composite thermal runaway protection material R-10 of the present invention, the adjacent battery No. 2 did not experience thermal runaway, and the time for the voltage of battery No. 1 to drop to 0 was nearly twice as long as the heating time of the blank sample. The maximum temperature of the battery during the entire test process was 257°C, which was more than 120°C lower than the temperature of the blank sample. The thermal conductivity of the composite thermal runaway protection material after the test was 0.218W / (mK), indicating that the material had a surplus and had not yet been completely decomposed. The maximum temperature of the adjacent battery No. 2 was 96°C. This is lower than the thermal runaway temperature of lithium iron phosphate batteries reported in the literature of 150°C (Mei Wenxin, et al. Simulation study on high-temperature thermal runaway of large lithium iron phosphate batteries [J]. Energy Storage Science and Technology, 2021, 10(1): 202-209).

[0167] In the test using the 30mm composite thermal runaway protection material R-30 of the present invention, the adjacent battery No. 2 did not experience thermal runaway, and the time for the voltage of battery No. 1 to drop to 0 was nearly 1.5 times longer than that of the blank sample. The maximum temperature of the battery during the entire test process was 232°C, which was more than 120°C lower than the temperature of the blank sample. The thermal conductivity of the composite thermal runaway protection material after the test was 0.502W / (mK), indicating that the material had a surplus and had not yet been completely decomposed. The maximum temperature of the adjacent battery No. 2 was 74°C. This is lower than the thermal runaway temperature of lithium iron phosphate batteries reported in the literature of 150°C (Mei Wenxin, et al. Simulation study on high-temperature thermal runaway of large lithium iron phosphate batteries [J]. Energy Storage Science and Technology, 2021, 10(1): 202-209).

[0168] The 2mm composite thermal runaway protection materials of Comparative Examples 1 to 3 were used for testing. No material extrusion occurred in Comparative Example 1. However, due to the low thermal enthalpy of the material, the heat of Battery No. 1 could not be quickly absorbed, and the ratio was not optimized. The thermal conductivity of the material after decomposition reached 0.158W / (mK), and the thermal insulation effect was also poor, causing the adjacent Battery No. 2 to eventually thermally runaway. The thermal runaway protection material of Comparative Example 2 was not tested because it could not be formed. The thermal runaway protection material of Comparative Example 3 had a low compression strength, and during the test, the material was squeezed and cracked, and then squeezed out, resulting in incomplete bonding between the material and the battery and a decrease in the amount of material. Although the time for the voltage of Battery No. 1 to drop to 0 was eventually extended, Battery No. 2 still experienced thermal runaway.

[0169] The above experiments fully demonstrate that the composite thermal runaway protection material prepared using the rapid prototyping process of the present invention has a significant effect in preventing the spread of battery thermal runaway by first absorbing heat to quickly reduce the battery temperature and then insulating to prevent heat from being transferred to adjacent batteries.

[0170] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection claimed by the present invention.

Claims

1. A rapid preparation method of a composite thermal runaway protection material, characterized in that: The composite thermal runaway protection material comprises the following components by mass percentage: 71-95% of inorganic heat-absorbing material, 0-5% of inorganic light-guiding material, 0-12% of polyvinyl alcohol, 0-1% of long-chain alkyl diacid, and 5-16% of UV-curable encapsulation resin; The rapid preparation method of the composite thermal runaway protection material is as follows: S1. Obtain a fluffy mixture by a mixing process; S2. Through a homogenization process, subject the fluffy mixture to secondary homogenization by a secondary homogenization device, with the temperature of the mixture during the homogenization process being 0-80°C, to obtain a uniform mixture; S3. Perform a shaping process and a curing process on the uniform mixture to obtain the composite thermal runaway protection material.

2. The rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: In the step S1, in the mixing process, the inorganic heat-absorbing material, inorganic light-guiding material, polyvinyl alcohol, long-chain alkyl diacid, and UV-curable encapsulation resin are added to a primary mixing device, while stirring, with the temperature range of the mixture during the mixing process being 0-80°C, the mixing time being greater than 10 minutes, and vacuum degassing to remove bubbles to obtain a fluffy mixture; The specific gravity of the fluffy mixture is less than 1 g / cm 3 ; In the step S3, in the shaping process, the uniform mixture is added to a mold and pressed by a press to obtain a shaped material, with the shaping temperature being 0-80°C and the shaping pressure being greater than 3 MPa; In the step S3, in the curing process, the shaped material is taken out and cured on one or both sides using an ultraviolet lamp, with the starting material temperature for curing being 0-60°C and the maximum temperature of the material after curing not exceeding 80°C.

3. The rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The method further includes a grinding process, in which the material after the curing process in step S3 is ground to obtain a composite thermal runaway protection material with a smooth and flat surface, and the temperature of the material during the grinding process does not exceed 80°C.

4. A rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: In the step S2, the secondary homogenization device includes any one of a three-roll mill, a calender, a sand mill, a roll press, or a colloid mill.

5. A rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The inorganic heat-absorbing material includes any one or a mixture of any proportions of sodium acetate trihydrate, ammonium iron(III) oxalate trihydrate, magnesium sulfate heptahydrate, zinc sulfate heptahydrate, sodium carbonate decahydrate, calcium chloride hexahydrate, magnesium chloride hexahydrate, aluminum nitrate nonahydrate, ammonium pentaborate octahydrate, ammonium iron(III) sulfate dodecahydrate, iron(II) chloride tetrahydrate, ammonium oxalate monohydrate, sodium tetraborate decahydrate, sodium tetraborate pentahydrate, aluminum sulfate octadecahydrate, ammonium pentaborate, ammonium tetraborate hydrogenate tetrahydrate, boric acid, barium hydroxide octahydrate, sodium metasilicate pentahydrate, hydrated aluminum silicate, silicic acid, hydrated silicic acid, potassium alum, sodium sulfate decahydrate, copper sulfate pentahydrate, ferrous sulfate heptahydrate, cobalt chloride hexahydrate, or calcium sulfate dihydrate.

6. The rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The inorganic light-guiding material is a material with transmittance to ultraviolet light, and includes any one or a mixture of any proportions of spherical silica powder, particulate silica powder, glass powder, quartz chopped fiber, or glass chopped fiber.

7. A rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The long-chain alkyl diacid includes any one or a mixture of any proportions of dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, or eicosanedioic acid; The polyvinyl alcohol is in powder form.

8. The rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The composite thermal runaway protection material is cut into a suitable size according to the structure of the battery pack and encapsulated using a sealed and pressure-resistant housing.

9. The rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The composite thermal runaway protection material is used alone as a thermal runaway protection material, or is combined with a heat-insulating material or a physical heat-insulating structure to form a thermal protection system.

10. The rapid preparation method of a composite thermal runaway protection material according to claim 1, characterized in that: The UV-curable encapsulation resin described above comprises, by mass percentage: 25-70% of silicone-epoxy resin composite modified polyurethane acrylate, 10-30% of silicone-polyurethane composite modified epoxy acrylate, 0-5% of epoxy resin, 5-40% of epoxy acrylate, 0-1% of acrylic acid, 5-30% of reactive monomer, 0-20% of silane modified resin, 0.1-3% of water scavenger, 0.1-3% of photoinitiator, and 0.01-0.3% of inhibitor; The preparation method of the UV-curable encapsulation resin is as follows: Add the silicone-epoxy resin composite modified polyurethane acrylate, silicone-polyurethane composite modified epoxy acrylate, epoxy resin, epoxy acrylate, acrylic acid, reactive monomer, silane modified resin, photoinitiator, and inhibitor in the above components into a reactor according to the ratio, maintain stirring at 50-60 °C for 2-3 hours, add the water scavenger, and after stirring for 10-30 minutes, obtain the UV-curable encapsulation resin.

11. A rapid preparation method of a composite thermal runaway protection material according to claim 10, characterized in that: The epoxy resin includes any one or a mixture of any proportions of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E epoxy resin, bisphenol S epoxy resin, epoxy soybean oil, cashew phenol modified epoxy resin, trimethylolpropane triglycidyl ether, hexanediol diglycidyl ether, or phenyl glycidyl ether; The epoxy acrylate includes CN104 NS or CN120 NS of Sartomer Company; The reactive monomer includes any one or a mixture of any proportions of isobornyl acrylate, cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, isobornyl methacrylate, or tetrahydrofurfuryl methacrylate; The silane modified resin is any one or a mixture of any proportions of silane modified polyether resin, silane modified polyacrylate resin, silane modified polyurethane resin, silane modified polyester resin, or alkoxy organosilicon resin; The water scavenger is p-toluenesulfonyl isocyanate; The photoinitiator includes any one or a mixture of any proportions of 4-benzoyl-4'-methyl-diphenyl sulfide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphinate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, benzoin dimethyl ether, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone, 1-hydroxycyclohexyl phenyl ketone, 4-acryloyloxybenzophenone, or methyl o-benzoylbenzoate; 12. A rapid preparation method of a composite thermal runaway protection material according to claim 10, characterized in that: The preparation method of the silicone-epoxy resin composite modified polyurethane acrylate is as follows: A1. Add diisocyanate and hydroxy acrylate into reactor A in a molar ratio of 1:1, add dibutyltin dilaurate as a catalyst at 0.01 - 0.2% of the total mass of diisocyanate and hydroxy acrylate, and p - methoxyphenol as an inhibitor at 0.01 - 0.2% of the total mass of diisocyanate and hydroxy acrylate. Heat up to 40 - 60 °C and react for 1 - 3 hours to obtain a semi - adduct of diisocyanate and hydroxyethyl acrylate, and calculate the theoretical NCO equivalent; A2. Add epoxy resin and mercapto - silane coupling agent into reactor B in a molar ratio of epoxy group to mercapto group of 1:1, add triethylamine as a catalyst at 0.01 - 0.2% of the total mass of epoxy resin and mercapto - silane coupling agent. Heat up to 70 - 90 °C and react for 1 - 3 hours to obtain silicone - modified epoxy resin, and calculate the theoretical hydroxyl equivalent; A3. According to the calculation method of NCO equivalent:hydroxyl equivalent = semi - adduct mass:silicone - modified epoxy resin mass, add a set amount of silicone - modified epoxy resin into reactor A, add dibutyltin dilaurate as a catalyst at 0.01 - 0.2% of the total mass of silicone - modified epoxy resin, and p - methoxyphenol as an inhibitor at 0.01 - 0.2% of the total mass of silicone - modified epoxy resin. Maintain the temperature at 60 - 80 °C and stir - react for 2 - 8 hours until the isocyanate absorption peak disappears to obtain the silicone - epoxy resin composite - modified polyurethane acrylate.

13. A rapid preparation method of a composite thermal runaway protection material according to claim 12, characterized in that: In step A1, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of diisocyanate and hydroxy acrylate; in step A2, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of epoxy resin and mercapto - silane coupling agent; or In step A1, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of diisocyanate and hydroxy acrylate; in step A3, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of silicone - modified epoxy resin; or In step A2, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of epoxy resin and mercapto - silane coupling agent; in step A3, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of silicone - modified epoxy resin; or In step A1, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of diisocyanate and hydroxy acrylate; in step A2, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of epoxy resin and mercapto - silane coupling agent; in step A3, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of silicone - modified epoxy resin.

14. A rapid preparation method of a composite thermal runaway protection material according to claim 12, characterized in that: In step A1, add acrylate monomers with 1 - 6 functional groups and no hydroxyl structure at 0 - 30% of the total mass of diisocyanate and hydroxy acrylate; or In step A2, acrylate monomers with 1-6 functional groups and without hydroxyl structure are added, accounting for 0-30% of the total mass of epoxy resin and mercapto silane coupling agent; Or In step A3, acrylate monomers with 1-6 functional groups and without hydroxyl structure are added, accounting for 0-30% of the total mass of the silicone-modified epoxy resin.

15. A rapid preparation method of a composite thermal runaway protection material according to claim 12, characterized in that: The hydroxy acrylate includes any one or a mixture in any proportion of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxybutyl acrylate or 4-hydroxybutyl acrylate; The epoxy resin includes any one or a mixture in any proportion of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E epoxy resin, bisphenol S epoxy resin, epoxy soybean oil, cashew phenol-modified epoxy resin, trimethylolpropane triglycidyl ether, hexanediol diglycidyl ether or phenyl glycidyl ether.

16. A rapid preparation method of a composite thermal runaway protection material according to claim 10, characterized in that: The preparation method of the silicone-polyurethane composite modified epoxy acrylate is as follows: B1. Add diisocyanate and mercapto silane coupling agent into reactor C in a molar ratio of 1:1, add 0.01-0.2% of the catalyst dibutyltin dilaurate based on the total mass of diisocyanate and mercapto silane coupling agent, heat up to 70-100 °C and react for 4-8 hours to obtain a semi-addition product of diisocyanate and mercapto silane coupling agent; B2. Add diisocyanate and epoxy acrylate into reactor C in a molar ratio of 1:1-1:0.5, add 0.01-0.2% of the catalyst dibutyltin dilaurate based on the total mass of epoxy acrylate, maintain the temperature at 70-90 °C and react for 1-3 hours to obtain the silicone-polyurethane composite modified epoxy acrylate.

17. A rapid preparation method of a composite thermal runaway protection material according to claim 16, characterized in that: In step B1, acrylate monomers with 1-6 functional groups and without hydroxyl structure are added, accounting for 0-30% of the total mass of diisocyanate and mercapto silane coupling agent; in step B2, acrylate monomers with 1-6 functional groups and without hydroxyl structure are added, accounting for 0-30% of the total mass of epoxy acrylate.

18. A rapid preparation method of a composite thermal runaway protection material according to claim 16, characterized in that: In step B1, acrylate monomers with 1-6 functional groups and without hydroxyl structure are added, accounting for 0-30% of the total mass of diisocyanate and mercapto silane coupling agent; Or in step B2, acrylate monomers with 1-6 functional groups and without hydroxyl structure are added, accounting for 0-30% of the total mass of epoxy acrylate.

19. In the rapid preparation method of a composite thermal runaway protection material according to any one of claims 12 to 18, it is characterized in that: The diisocyanate includes any one or a mixture in any proportion of hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, xylylene diisocyanate, trimethylhexane diisocyanate, 1,5-naphthalene diisocyanate or diphenylmethane diisocyanate; The mercapto silane coupling agent includes any one or a mixture in any proportion of mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptopropylmethyldimethoxysilane or mercaptopropylmethyldiethoxysilane.

20. In the rapid preparation method of a composite thermal runaway protection material according to any one of claims 13, 14, 17 or 18, it is characterized in that: The acrylate monomer includes any one or more of isobornyl acrylate, cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, isobornyl methacrylate, or tetrahydrofurfuryl methacrylate, or a mixture thereof in any proportion.

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