Fire-fighting aerogel fire extinguishing agent, fire extinguishing device and release method

Abstract

The invention discloses an aerogel fire extinguishing agent for fire fighting, a fire extinguishing device and a releasing method.The aerogel fire extinguishing agent for fire fighting is prepared from, by mass, 8-12 parts of silicon dioxide aerogel powder, 40-45 parts of perfluorohexanone, 1.5-2 parts of zinc molybdate, 0.8-1.2 parts of nano cerium oxide, 2-3 parts of hyperbranched polysiloxane and 0.2-0.3 part of 18-crown-6 ether. Solid-phase silicon dioxide aerogel powder is matched with liquid-phase perfluorohexanone, zinc molybdate, nano cerium oxide, hyperbranched polysiloxane, 18-crown-6 ether and the like are compounded to serve as auxiliaries, efficient fire extinguishing can be conducted on precise electrical elements, residues are few, loss of instruments and equipment is small, and the fire extinguishing agent is suitable for being applied to the electrical field.

Description

Technical Field

[0001] This application relates to fire fighting, and more particularly to an aerogel fire extinguishing agent, fire extinguishing device, and release method for fire fighting. Background Technology

[0002] In the field of fire protection, efficient and equipment-friendly fire extinguishing technologies have always been a focus of research and development. With the widespread use of modern electronic equipment and electrical systems, the risk of electrical fires is increasing. These fires are typically accompanied by high temperatures, the generation of highly toxic gases, and potential secondary circuit breaks and reignition problems. Traditional fire extinguishing technologies are no longer sufficient to meet the demands for efficient extinguishing of precision electrical components, minimizing residue, and reducing damage to instruments and equipment. Developing high-performance fire extinguishing agents and devices suitable for the electrical field is of great significance for ensuring personnel safety and reducing property damage.

[0003] Currently, common methods for extinguishing electrical fires include using pure water and commercially available dry powder extinguishing agents. Pure water extinguishing primarily works by cooling the burning material, but for electrical fires, water may cause secondary disasters such as short circuits, and its ability to suppress high temperatures and handle highly toxic gases is limited. Commercially available dry powder extinguishing agents work by covering the surface of the burning material with dry powder, isolating it from oxygen. However, dry powder can cause significant residue and damage to precision electrical components and may not be effective in suppressing highly toxic substances produced during combustion or preventing reignition.

[0004] However, existing fire extinguishing technologies have significant shortcomings. For example, in dealing with electrical fires, traditional extinguishing agents cannot effectively address the secondary circuit breakage and reignition problems caused by "free ions migrating under an electric field, forming micro-current pathways that lead to a sharp drop in volume resistivity." Furthermore, they lack the capacity to handle highly toxic substances such as dioxin precursors from the combustion of chlorinated plastics and HF produced by the thermal decomposition of lithium salts, making it difficult to meet the requirements of efficient fire extinguishing of precision electrical components with minimal residue and damage to equipment. Summary of the Invention

[0005] To address lithium battery combustion, an aerogel fire extinguishing agent, fire extinguishing device, and method for firefighting are provided.

[0006] The first inventive objective of this invention is achieved through the following technical solution: A fire extinguishing aerogel comprising the following raw materials in parts by weight: 8-12 parts of silica aerogel powder 40-45 parts of perfluorohexanone 2-3 parts of hyperbranched polysiloxane 0.2 to 0.3 parts of 18-crown-6 ether.

[0007] By adopting the above technical solution, this application uses solid-phase silica aerogel powder combined with liquid-phase perfluorohexanone, and compounded with hyperbranched polysiloxane and 18-crown-6 ether as additives. Perfluorohexanone, as a gas-phase fire extinguishing agent, effectively extinguishes open flames by chemically interrupting the free radical chain reaction (generating free radicals such as CF3) and rapidly absorbing the heat of electrolyte decomposition. When silica aerogel powder is used as a solid fire extinguishing agent and covered on the surface of a thermal runaway battery, its nanoporous structure can block heat conduction between battery modules, inhibit heat spread, and adsorb highly toxic gases such as HF and POF3. In addition, the nano-sized porous carriers on the silica aerogel powder adsorb perfluorohexanone and delay its volatilization, forming a "solid-gas" synergistic fire extinguishing system with perfluorohexanone, combining physical coverage and chemical inhibition. Hyperbranched polysiloxane, as a thickener, prevents solid-phase sedimentation and ensures that the extinguishing agent evenly covers the battery gaps during high-pressure injection. This is the key to the normal injection and stable storage of the compound perfluorohexanone and silica aerogel powder in this application. During the preparation of silica aerogel powder, impurities and equipment contact may leave residual metal ions, which will also dissolve ions (Ni²⁺ / Co³⁺) during battery thermal runaway. There is a problem that "free ions migrate under the electric field, forming micro-current pathways that cause a sharp drop in volume resistivity, which can lead to secondary circuit breakage and reignition." 18-crown-6 ether chelates metal dissolved ions (Ni²⁺ / Co³⁺) in the battery. The chelate size cannot pass through the aerogel pores, thus blocking the ion migration path. Furthermore, the chelate bond energy remains stable under ultra-high pressure, which increases the volume resistivity of the fire extinguishing agent covering and prevents secondary short circuits. In summary, the fire extinguishing aerogel agent of this application can effectively extinguish fires on precision electrical components, leaving little residue and causing minimal damage to instruments and equipment, making it suitable for application in the electrical field.

[0008] Optionally, it may also include 1.5 to 2 parts of zinc molybdate and 0.8 to 1.2 parts of nano-cerium oxide.

[0009] By adopting the above technical solution, zinc molybdate and nano-cerium oxide are combined to form a catalytic system that catalytically decomposes dioxin precursors produced by the combustion of chlorine-containing plastics, adsorbs and catalytically degrades hydrogen chloride, and also specifically decomposes HF produced by the thermal decomposition of lithium salt (LiPF6), reducing the generation of highly toxic substances.

[0010] Optionally, the silica aerogel is modified with tetraethoxyfluorosilane to achieve fluorine-doped silica aerogel.

[0011] By adopting the above technical solutions, fluorine doping enhances the Si-O bond energy, improves the temperature resistance of silica aerogel powder, and resists the high temperature of battery thermal runaway; it also reduces the surface energy of silica aerogel powder and improves the electrolyte wetting barrier properties. Furthermore, it enhances the siloxane bonding strength of hyperbranched polysiloxanes and reduces surface energy, thereby improving the anti-settling properties of silica aerogel powder in perfluorohexane, making spraying and storage more stable.

[0012] Optionally, it may also include 1.2 to 1.5 parts of fluorinated alumina nanosheets.

[0013] By adopting the above technical solution, fluorinated alumina nanosheets form a thermally conductive barrier on the battery surface, blocking heat conduction; in addition, they work synergistically with perfluorohexanone to enhance the thermal decomposition efficiency of perfluorohexanone and shorten the fire extinguishing time.

[0014] Optionally, the silica aerogel powder is hydrophobically modified with hexamethyldisilazane.

[0015] By adopting the above technical solution, the surface silanol hydroxyl group Si-OH is replaced by Si-O-Si(CH3)3, which eliminates the formation of a conductive water film by the adsorption of environmental moisture, increases the contact angle of silica aerogel powder, adapts to the thermal runaway vapor environment of the battery, and can block external liquid from penetrating into the micropores of the circuit board after the silica aerogel powder is covered, thus avoiding the risk of micro short circuit.

[0016] Optionally, 2 to 3 parts of perfluoropolyether oil may also be included.

[0017] By adopting the above technical solution, perfluoropolyether oil can rapidly spread and form a self-healing insulating film on the surface of battery electrodes, blocking plasma channels and preventing the chain reaction of insulation failure caused by "high-temperature arc-induced dielectric carbonization of conductive paths → secondary combustion and explosion," thus enhancing fire extinguishing and protective effects. It also delays oxygen release from the positive electrode material, inhibiting the reignition chain reaction. Furthermore, when used in conjunction with silica aerogel powder, it can delay the high-temperature decomposition of perfluoropolyether oil, providing long-lasting protection.

[0018] Optionally, it may also include 6-8 parts of core-shell SiO2@ammonium polyphosphate.

[0019] By adopting the above technical solution The core-shell type SiO2@ammonium polyphosphate expands and spreads upon exposure to fire, isolating oxygen and adsorbing liquid electrolyte; the SiO2 shell reacts with HF to generate SiF4, reducing the release of corrosive gases; when used with perfluoropolyether oil, the expanded carbon layer is wetted by the perfluoropolyether oil, further improving the oxygen isolation efficiency.

[0020] The second objective of this invention is achieved through the following technical solution: A fire extinguishing device for fire fighting, characterized in that it includes a container, a release mechanism and a nozzle, wherein the release mechanism includes a compressed nitrogen storage tank with an on / off valve, the on / off valve is connected to the container, the nozzle is connected to the container, and the container contains the aforementioned fire-fighting aerogel extinguishing agent.

[0021] By adopting the above technical solution, it is possible to extinguish fires on precision electrical components efficiently, with minimal residue and minimal damage to instruments and equipment, making it suitable for application in the electrical field.

[0022] The third inventive objective of this invention is achieved through the following technical solution: A method for releasing extinguishing agent, using the above-mentioned fire extinguishing device, directing the nozzle toward the fire source and opening the valve.

[0023] By adopting the above technical solution, it is possible to extinguish fires on precision electrical components efficiently, with minimal residue and minimal damage to instruments and equipment, making it suitable for application in the electrical field.

[0024] In summary, this application has at least the following beneficial effects: This application uses solid-phase silica aerogel powder combined with liquid-phase perfluorohexanone, and is further formulated with zinc molybdate, nano-cerium oxide, hyperbranched polysiloxane and 18-crown-6 ether as additives. It can effectively extinguish fires on precision electrical components with little residue and minimal damage to instruments and equipment, making it suitable for application in the electrical field. Detailed Implementation

[0025] Ethyl orthosilicate is an Evonik industrial product with a purity of 99.7 wt%.

[0026] Tetraethoxyfluorosilane is a product of Gelest Inc., electronic grade, with a purity ≥99.9 wt%.

[0027] Perfluorooctyltriethoxysilane is a product of Shin-Etsu Chemical, with a purity of 98.4 wt%.

[0028] Hyperbranched polysiloxanes are Wacker Chemie products with a molecular weight range of 12,000 to 20,000.

[0029] Hexamethyldisilazane is a product of Zhejiang Xin'an Chemical Co., Ltd., and conforms to electronic-grade MOS standards.

[0030] Aluminum isopropoxide is Arafaeza, with a purity of 99.5%.

[0031] Ammonium polyphosphate is a product of Klein Chemicals (Switzerland) with a degree of polymerization of 1200.

[0032] Zinc molybdate is a commercially available product with a purity of 99.9 wt% and a particle size of 2 μm.

[0033] The nano-cerium oxide is a commercially available product with a purity of 99.9 wt% and a particle size of 20 nm.

[0034] Perfluorohexanone is a product of 3M.

[0035] The perfluoropolyether oil is a Solvay product of high-temperature lubrication grade PFPE.

[0036] The 18-crown-6 ether is from TCI Chemicals and has a purity of 99.5 wt%.

[0037] Oxalic acid solution, hydrofluoric acid, hydrochloric acid, and ammonia are all commercially available industrial-grade raw materials. Their concentrations are indicated in the usage section below.

[0038] Anhydrous ethanol and liquid CO2 are both commercially available industrial-grade raw materials.

[0039] Preparation Example 1 A silica aerogel powder, which is neither hydrophobically modified nor fluorine-doped. The specific preparation process is as follows: Mix 1 mol tetraethyl orthosilicate, 4 mol anhydrous ethanol, and 4 mol deionized water, and add 0.1 mol / L hydrochloric acid to adjust the pH to 3.5. Stir and hydrolyze at 40°C for 2 hours to form a homogeneous sol. Add 28wt% ammonia to adjust the pH to 6.0, and let it stand for 50 minutes at 25℃ and 50% relative humidity to gel. The wet gel was transferred to 10 times its volume of anhydrous ethanol and aged for 72 hours, with fresh anhydrous ethanol replaced every 12 hours during the aging process. The gel block was obtained by filtration and then subjected to atmospheric pressure step drying at 80℃ for 4 h, 100℃ for 4 h, and 120℃ for 4 h respectively. The dried block was gently ground and sieved to obtain powder with a particle size distribution of 23~33μm and D50=28μm.

[0040] The results of the powder physical property parameter testing are shown in Table 1.

[0041] Preparation Example 2 A silica aerogel powder, which is hydrophobically modified and fluorine-free. The specific preparation process is as follows: Mix 1 mol tetraethyl orthosilicate, 4 mol anhydrous ethanol, and 4 mol deionized water, and add 0.1 mol / L hydrochloric acid to adjust the pH to 3.5. Stir and hydrolyze at 40°C for 2 hours to form a homogeneous sol. Hexamethyldisilazane was added to the sol in an amount that was 6% of the molar amount of tetraethyl orthosilicate, i.e., 0.06 mol. The mixture was stirred at 25°C for 3 hours. During the reaction, the byproduct ammonia was removed under vacuum at a pressure of 0.095 MPa. Add 28wt% ammonia to adjust the pH to 6.0, and let it stand for 50 minutes at 25℃ and 50% relative humidity to gel. The wet gel was transferred to 10 times its volume of anhydrous ethanol and aged for 72 hours, with fresh ethanol replaced every 12 hours during the process. The solid obtained by filtration was subjected to atmospheric pressure step drying at 80℃ for 4 hours, 100℃ for 4 hours, and 120℃ for 4 hours in sequence. The dried block was gently ground and sieved to obtain powder with a particle size distribution of 23~33μm and D50=28μm.

[0042] The results of the powder physical property parameter testing are shown in Table 1.

[0043] Preparation Example 3 A silica aerogel powder, which is fluorine-doped and unmodified by hydrophobicity. The specific preparation process is as follows: Mix 0.9 mol of tetraethyl orthosilicate with 0.1 mol of tetraethoxyfluorosilane, preheat at 40°C for 5 min to obtain silicon source solution; 1 mol of anhydrous ethanol was premixed with 3 mol of deionized water, and the pH was adjusted to 4.5 by adding 0.05 mol / L oxalic acid solution to obtain a mixed solution. The mixture was added dropwise to the silicon source solution at a rate of 2 mL / min, and stirred at 60 °C and 400 rpm for 4 h to obtain a sol. Add 28wt% ammonia water dropwise to the sol to adjust the pH to 5.5, and let it stand for 100 minutes at 25℃ and 50% relative humidity until the gel forms. The wet gel was immersed in 10 times its volume of anhydrous ethanol for 72 hours, and the ethanol was replaced every 12 hours to obtain the aged gel. The aged gel was placed in an autoclave, and the residual solvent was replaced with liquid CO2 at a pressure of 8 MPa for 2 hours. After replacement, the temperature was increased to 50°C and the pressure was increased to 12 MPa, and the pressure was maintained for 4 hours. Finally, the pressure was reduced at a rate of 0.5 MPa / min to obtain a dried block. The dried block was gently ground and sieved to obtain powder with a particle size distribution of 23~33μm and D50=28μm.

[0044] The results of the powder physical property parameter testing are shown in Table 1.

[0045] Preparation Example 4 A silica aerogel powder, which is fluorine-doped and hydrophobically modified. The specific preparation process is as follows: Mix 0.9 mol of tetraethyl orthosilicate with 0.1 mol of tetraethoxyfluorosilane, preheat at 40°C for 5 min to obtain silicon source solution; 1 mol of anhydrous ethanol was premixed with 3 mol of deionized water, and the pH was adjusted to 4.5 by adding 0.05 mol / L oxalic acid solution to obtain a mixed solution. The mixture was added dropwise to the silicon source solution at a rate of 2 mL / min, and stirred at 60 °C and 400 rpm for 4 h to obtain a sol. Hexamethyldisilazane was added to the sol at a rate of 6% of the total silicon source molar, which is 0.06 mol in this case. The reaction was carried out at 40 °C and 350 rpm for 2 h with stirring. During the reaction, the byproduct ammonia was removed under vacuum at a pressure of 0.095 MPa. Add 28wt% ammonia to adjust the pH to 6.0, and let it stand for 100 minutes at 25℃ and 50% relative humidity to gel. The wet gel was transferred to 10 times its volume of anhydrous ethanol and aged for 72 hours, with fresh ethanol replaced every 12 hours during the process. The aged gel was placed in an autoclave, and the residual solvent was replaced with liquid CO2 at a pressure of 8 MPa for 2 hours. After replacement, the temperature was increased to 50°C and the pressure was increased to 12 MPa, and the pressure was maintained for 4 hours. Finally, the pressure was reduced at a rate of 0.5 MPa / min to obtain a dried block. The dried block was gently ground and sieved to obtain powder with a particle size distribution of 23~33μm and D50=28μm.

[0046] The results of the powder physical property parameter testing are shown in Table 1.

[0047] Table 1. Physical properties of silica aerogel powders obtained in Preparation Examples 1 to 4

[0048] Preparation Example 5 The preparation process of fluorinated alumina nanosheets is as follows: 50 kg of aluminum isopropoxide and 5000 L of deionized water were added to a reaction vessel and stirred at 200 rpm for 2 h at 80 °C to generate a milky white pseudoboehmite suspension. Add 18 L of 40% hydrofluoric acid dropwise to the suspension to adjust the pH to 4.0, heat to 90℃ and reflux for 6 h to obtain a transparent sol; Add 80L of 28wt% ammonia solution to the sol, adjust the pH to 9.5, and age at 60℃ for 12h to generate γ-AlOOH precipitate; The γ-AlOOH precipitate was transferred to a 6000L Hastelloy autoclave and crystallized at 180℃ and 1.2MPa for 48h. After cooling, it was filtered to obtain flake-like γ-AlOOH with a flake diameter of 200±50nm and a thickness of 20±5nm. Flake-shaped γ-AlOOH (50 kg dry weight) was loaded into a quartz fluidized bed, and anhydrous HF gas (flow rate 50 L / min) was passed through it. The reaction was carried out at 400℃ for 2 h to obtain fluorinated powder with the composition Al2O3·AlF3. Fluorinated powder was immersed in a modification solution and ultrasonically treated at 60℃ and 40kHz for 30 minutes. The modification solution was obtained by mixing 5 kg of perfluorooctyltriethoxysilane and 500 L of anhydrous ethanol. The ultrasonically treated material was centrifuged at 3000 rpm for 10 min, and the solid was dried at 120℃ under vacuum for 4 h until the moisture content was <0.1 wt%, thus obtaining the dried material. The dried material was pulverized by air jet milling to control the particle size D50=150nm, and then vibrated and sieved to obtain fluorinated alumina nanosheets with a particle size of 150nm.

[0049] The fluorine content in the fluorinated alumina nanosheets was found to be 22.5 wt%, and the water contact angle was 110°.

[0050] Preparation Example 6 The preparation method of core-shell SiO2@ammonium polyphosphate is as follows: 1 kg of ammonium polyphosphate was added to 40 L of deionized water, heated to 70 °C, stirred at 300 rpm for 2 h, filtered, and dried under vacuum at 60 °C until the moisture content was ≤0.5 wt% to obtain pretreated ammonium polyphosphate. 10L of anhydrous ethanol and 1L of deionized water were mixed as a mixed solvent, and the pretreated ammonium polyphosphate was dispersed in the mixed solvent to obtain ammonium polyphosphate slurry. Adjust the pH of 1.5L of deionized water to 4.0 with 1mol / L hydrochloric acid to obtain a dilute acid solution; 0.3 kg of tetraethyl orthosilicate and 3 L of ethanol were stirred at 200 rpm for 10 min, then dilute acid solution was added and stirring was continued for 1 h to obtain a pre-hydrolyzed tetraethyl orthosilicate solution. The temperature of the ammonium polyphosphate slurry was stabilized at 60°C, the stirring speed was adjusted to 400 pm, and the pre-hydrolyzed tetraethyl orthosilicate solution was uniformly added dropwise to the ammonium polyphosphate slurry over 1 hour. After the tetraethyl orthosilicate was added, 28 wt% ammonia was added to adjust the pH to 10. Then, the pH of the liquid phase was stabilized to 10 by adding ammonia dropwise, and the reaction was continued for 7 hours. The material was cooled to 25°C. The solid obtained from solid-liquid separation was washed alternately with ethanol and deionized water until the washing liquid was neutral and no chloride ions were detected by AgNO3. The solid was dried at 80°C and 0.08MPa vacuum for 10 hours. The dried material was then crushed and screened to obtain core-shell SiO2@ammonium polyphosphate with a particle size of 25μm.

[0051] Example 1 A fire extinguishing aerogel, the raw materials of which are silica aerogel powder, perfluorohexanone, zinc molybdate, nano-cerium oxide, hyperbranched polysiloxane, 18-crown-6 ether, fluorinated alumina nanosheets, perfluoropolyether oil and core-shell SiO2@ammonium polyphosphate.

[0052] The specific preparation method is as follows: 10 kg of silica aerogel powder from Preparation Example 4 and 42.5 kg of perfluorohexanone were added to a pre-cooled reactor at 4°C and stirred at 200 rpm for 30 min to allow the aerogel nanopores to fully adsorb the perfluorohexanone. Heat the reactor to 15°C, add 1.75 kg zinc molybdate, 1.0 kg nano cerium oxide, and 2.5 kg hyperbranched polysiloxane, and stir at 500 rpm and 15°C for 45 min. 1.35 kg of the fluorinated alumina nanosheets prepared in Preparation Example 5 were premixed with 2.5 kg of perfluorinated polyether oil to obtain a premix. The premix and 0.25 kg of 18-crown-6 ether were added to a reaction vessel and stirred at 400 rpm and 15 °C for 30 min. The core-shell type SiO2@ammonium polyphosphate prepared in Preparation Example 6 was added while stirring at 300 rpm. The amount added was 7 kg, and the addition rate was controlled at 1 kg / min. After the addition was completed, stirring was continued for 10 min to obtain a mixture. The mixture was subjected to high-pressure homogenization. The first-stage homogenization pressure was 50 MPa, and the first-stage homogenization cycle was repeated 3 times. The second-stage homogenization pressure was 10 MPa, and the second-stage homogenization cycle was repeated once to obtain a homogenized material. The homogeneous material was stored in an insulated storage tank and aged at 10°C for 6 hours. During the aging process, the stirring was started every 2 hours and stirred at 20 rpm for 1 minute to prevent sedimentation, thus obtaining a canned fire extinguishing agent.

[0053] The extinguishing agent can be dispensed into the container using a diaphragm pump, with nitrogen replacing oxygen before dispensing.

[0054] Comparative Example 1 A fire extinguishing aerogel, which differs from Example 1 in that it replaces the hyperbranched polysiloxane with an additional amount of perfluorohexanone by mass.

[0055] Comparative Example 1 A fire extinguishing aerogel, differing from Example 1 in that it replaces 18-crown-6 ether with an additional amount of perfluorohexanone by mass.

[0056] Example 2 A fire extinguishing aerogel agent for fire fighting, which differs from Example 1 in that the silica aerogel powder used is prepared in Example 1.

[0057] Example 3 A fire extinguishing aerogel agent for fire fighting, which differs from Example 1 in that the silica aerogel powder used is prepared in Example 2.

[0058] Example 4 A fire extinguishing aerogel agent for fire fighting, which differs from Example 1 in that the silica aerogel powder used is prepared in Example 3.

[0059] Example 5 A fire extinguishing aerogel agent for fire fighting differs from Example 1 in that it does not contain fluorinated alumina nanosheets in the raw materials, i.e., the amount of fluorinated alumina nanosheets used is 0.

[0060] Example 6 A fire extinguishing aerogel agent for firefighting differs from Example 1 in that perfluorohexanone is used instead of perfluoropolyether oil in the raw materials.

[0061] Example 7 A fire extinguishing aerogel agent for fire fighting, which differs from Example 1 in that core-shell SiO2@ammonium polyphosphate is not added to the raw materials, that is, the amount of core-shell SiO2@ammonium polyphosphate is 0.

[0062] Example 9 A fire extinguishing aerogel, which differs from Example 1 in the amount of raw materials used, is as follows: 8 kg silica aerogel powder, 40 kg perfluorohexanone, 1.5 kg zinc molybdate, 0.8 kg nano-cerium oxide, 2 kg hyperbranched polysiloxane, 1.2 kg fluorinated alumina nanosheets, 2 kg perfluoropolyether oil, 0.2 kg 18-crown-6 ether, and 6 kg core-shell SiO2@ammonium polyphosphate.

[0063] Example 10 A fire extinguishing aerogel agent for fire fighting differs from Example 1 in the amount of raw materials used, specifically as follows: 12 kg silica aerogel powder, 45 kg perfluorohexanone, 2 kg zinc molybdate, 1.2 kg nano-cerium oxide, 3 kg hyperbranched polysiloxane, 1.2 kg fluorinated alumina nanosheets, 3 kg perfluoropolyether oil, 0.3 kg 18-crown-6 ether, and 8 kg core-shell SiO2@ammonium polyphosphate.

[0064] Fire extinguishing performance test at an ambient relative humidity of 30% The same batch of lithium batteries were purchased. The lithium batteries were brand new NMC square ternary lithium batteries, 3.7V, 50Ah, 100% SOC, with dimensions of 110mm×65mm×10mm. Four batteries were placed together along the thickness (10mm) direction, and all positive terminals and all negative terminals were connected with connectors. The batteries were then bound and fixed on the sides with fiberglass tape to form a battery pack, which was used as the test object.

[0065] A thermocouple temperature sensor was attached to the surface of the battery pack to monitor the surface temperature of the battery pack. The initial ambient temperature was 25°C and the relative humidity was 30%.

[0066] The lithium-ion battery is heated to 250°C by heating elements. When the battery begins to thermally run away, the fire extinguishing agent is released. The time it takes for the open flame to be extinguished, whether the open flame reignites within 3 hours after it is extinguished, the battery surface temperature at the start of the fire extinguishing, and the battery surface temperature after the fire is extinguished are recorded.

[0067] Pure water and commercially available dry powder fire extinguishing agents were used as control groups.

[0068] Fire extinguishing performance test at an ambient relative humidity of 80% The method for testing fire extinguishing performance is the same as that for an environment with a relative humidity of 30%, but the difference is that the relative humidity of the test environment is 80%, and the test is conducted to check whether the open flame reignites within 3 hours after it is extinguished.

[0069] Fire extinguishing performance test at 100% relative humidity Refer to the fire extinguishing performance test method when the relative humidity of the environment is 30%, the difference is that the relative humidity of the test environment is 100%, and the test is conducted to see if the open flame reignites within 3 hours after it is extinguished.

[0070] Condensate wetting and reignition test Based on the fire extinguishing performance test at an ambient relative humidity of 100%, water mist was sprayed vertically downwards above the battery pack after the fire was extinguished. Tap water was used as the water source to replace the contaminated condensate dripping from the surface of the simulated combustion environment. The water mist spray rate was 40 ml / (h·m). 2 ), to check whether the battery pack reignites within 3 hours after the fire is extinguished.

[0071] Stability test The extinguishing agent was left to stand in a 10℃ constant temperature chamber for 24 hours to eliminate the effects of transportation disturbance. The sample was redispersed using a magnetic stirrer (200 rpm, 10 min) to ensure uniform suspension of the solid phase; Take 10ml of extinguishing agent and measure its solid content, record it as the initial fixed content; Select a settling tube made of transparent quartz glass, with an inner diameter of 25mm, a height of 300mm, and a 0.1mm graduation scale, and inject 50mL of extinguishing agent; The settling pipe filled with extinguishing agent was vertically fixed in a constant temperature chamber (10℃±0.5℃) to avoid vibration, and the initial liquid level was recorded by photograph. Ho ), After 30 days of storage, the height of the solid settlement layer was measured. Hs Extract the top 10 mL of liquid, measure the solid content, and record it as the solid content after standing.

[0072] calculate: Settlement height ratio (%) = H s ÷H o ×100%; Top solids retention rate = solids content after standing ÷ initial solids content × 100%.

[0073] Table 2. Fire extinguishing performance test results at 30% relative humidity

[0074] Table 3. Fire Extinguishing Performance Test Results at 80% Relative Humidity

[0075] Table 4. Fire Extinguishing Performance Test Results at 100% Relative Humidity

[0076] Table 5. Results of the test for the re-ignition property of condensate water wetting

[0077] Table 6. Stability test results of Examples 1-10 and Comparative Examples 1-2

[0078] As shown in Tables 2-6, pure water in the control group could not effectively extinguish lithium battery fires; commercially available dry powder fire extinguishers could extinguish open flames from lithium battery fires, but lithium batteries had a high risk of reignition in relatively humid environments.

[0079] Furthermore, since the fire source is a lithium battery, an increase in relative humidity in the environment cannot suppress its combustion. The test results show that the extinguishing time of the open flame is not fixed as the relative humidity of the environment increases.

[0080] Comparing Example 1 and Comparative Examples 1-2, it can be seen that Comparative Example 1 did not contain hyperbranched polysiloxane compared to Example 1, and Comparative Example 2 did not contain 18-crown-6 ether compared to Example 1.

[0081] In the fire extinguishing performance test, the flame extinguishing time of Comparative Example 1 was longer than that of Example 1, and the surface temperature of the lithium battery after extinguishing was higher than that of Example 1. Therefore, the fire extinguishing performance of Example 1 was better than that of Comparative Example 1. In the stability test, the settling height ratio of Comparative Example 1 was significantly greater than that of Example 1, and the top solid phase retention rate of Comparative Example 1 was significantly lower than that of Example 1. Therefore, the stability of the fire extinguishing agent of Example 1 was significantly better than that of Comparative Example 1.

[0082] The reason is that hyperbranched polysiloxane, as a thickener, is the key to the normal spraying and stable storage of the compounded perfluorohexanone and silica aerogel powder in this application. It can effectively prevent solid phase sedimentation, ensure that the extinguishing agent evenly covers the battery gaps during high-pressure spraying, quickly extinguish open flames, completely block heat conduction between battery modules, and reduce secondary ignition caused by battery modules.

[0083] In the fire extinguishing performance test, the flame extinguishing time of Example 1 was significantly shorter than that of Comparative Example 2. The surface temperature of the lithium battery after extinguishing the fire in Example 1 was significantly lower than that in Comparative Example 2. Furthermore, Example 1 did not reignite within 3 hours when tested with an ambient relative humidity of 80% and 100% and when wetted with condensate. Therefore, the fire extinguishing performance of Example 1 was significantly better than that of Comparative Example 2.

[0084] The reason is that during the preparation of silica aerogel powder, impurities and equipment contact may leave residual metal ions, which will also dissolve ions (Ni²⁺ / Co³⁺) during battery thermal runaway. There is a problem that "free ions migrate under the electric field, forming a micro-current path that causes a sharp drop in volume resistivity," leading to a secondary circuit break and causing reignition. The 18-crown-6 ether added in Example 1 of this application, compared to Comparative Example 1, can chelate the dissolved metal ions (Ni²⁺ / Co³⁺) from the battery. The chelate size cannot pass through the aerogel channels, thus blocking the ion migration path. Moreover, the chelate bond energy is high and remains stable under ultra-high pressure, which increases the volume resistivity of the fire extinguishing agent covering and prevents secondary combustion caused by short circuit. Therefore, it significantly improves the fire extinguishing performance of the fire extinguishing agent of this application.

[0085] Comparing Examples 1 to 4, it can be seen that the silica aerogel powder used in Examples 1 to 4 is different.

[0086] The silica aerogel powder used in Example 1 was fluorinated by tetraethoxyfluorosilane and hydrophobically modified with hexamethyldisilazane. The silica aerogel powder used in Example 2 was free of fluorine doping and hydrophobic modification; The silica aerogel powder used in Example 3 was hydrophobically modified with hexamethyldisilazane, but without fluorine doping; The silica aerogel powder used in Example 3 was not hydrophobically modified but was doped with fluorine.

[0087] Furthermore, as can be seen from Table 1, the silica aerogel powder used in Examples 1 and 3 underwent hydrophobic modification, and its water contact angle was selected to be greater than that of the silica aerogel powder used in Example 2. The fluorine doping of the silica aerogel powder used in Examples 1 and 4 was determined to be effective doping.

[0088] In the fire extinguishing performance test results, the flame extinguishing time of Example 3 was shorter than that of Example 2. In the reignition test, Example 3 did not reignite in ambient humidity of 80% and 100%, while Example 2 reignited at 100% ambient humidity. Therefore, the fire extinguishing performance of Example 3 is better than that of Example 2, especially in terms of reignition prevention. Therefore, in this application, the surface of silica aerogel powder is modified to be hydrophobic, which replaces the surface silanol groups Si-OH with Si-O-Si(CH3)3, thereby avoiding the adsorption of ambient moisture to form a conductive water film, increasing the contact angle of silica aerogel powder, adapting to the battery thermal runaway vapor environment, and after the silica aerogel powder is covered, it can block the penetration of external liquid into the micropores of the circuit board, avoid the risk of micro-short circuit, and suppress the risk of reignition.

[0089] In the fire extinguishing performance test, the flame extinguishing time of Example 4 was significantly shorter than that of Example 2, and the surface temperature of the fire extinguishing battery was significantly lower than that of Example 2. Therefore, the fire extinguishing performance of Example 4 was significantly better than that of Example 2. In the stability test, the settling height ratio of Example 4 was significantly lower than that of Example 2, and the top solid phase retention rate of Example 4 was significantly higher than that of Example 2. Therefore, the stability of Example 4 was significantly better than that of Example 2.

[0090] The reason is that the silica aerogel powder described in Example 2 is doped with fluorine, which enhances the Si-O bond energy, improves the temperature resistance of the silica aerogel powder, and resists the high temperature of battery thermal runaway. In addition, it also reduces the surface energy of the silica aerogel powder and improves the electrolyte wetting barrier. As a result, the high temperature stability, heat insulation and barrier properties are improved, the fire extinguishing time is shortened and the battery temperature is reduced after the fire is extinguished, which can reduce the impact on other surrounding equipment and batteries.

[0091] Furthermore, the fluorine-doped silica aerogel powder exhibits enhanced siloxane bonding strength with hyperbranched polysiloxanes. Combined with the reduction in surface energy, this improves the anti-settling properties of silica aerogel powder in perfluorohexane, making spraying and storage more stable.

[0092] Based on the test results of Example 1, it can be seen that fluorine doping and hydrophobic modification of silica aerogel powder can be carried out simultaneously without conflict, and can even have a synergistic effect, further enhancing the fire extinguishing performance and stability of the fire extinguishing agent.

[0093] Comparing Example 1 and Example 5, it can be seen that Example 1, compared with Example 5, additionally added the fluorinated alumina nanosheets prepared in this application.

[0094] In the fire extinguishing performance test, Example 1 not only had a shorter flame extinguishing time than Example 5, but the temperature after extinguishing the fire in Example 1 was also lower than that in Example 5. Therefore, the fire extinguishing performance of Example 1 is better than that of Example 5. In the stability test, the settling height ratio and the top solid phase retention rate of Example 1 and Example 5 are similar.

[0095] Therefore, it can be seen that the addition of fluorinated alumina nanosheets to the fire extinguishing agent of this application will not damage the stability of the fire extinguishing agent, and at the same time improve its fire extinguishing performance. Fluorinated alumina nanosheets can form a thermally conductive barrier on the battery surface to block heat conduction, but the barrier performance is not significantly superior to that of silica aerogel. The reason for the improved fire extinguishing performance of the fire extinguishing agent is that the fluorinated alumina nanosheets also synergize with perfluorohexanone, enhancing the thermal decomposition efficiency of perfluorohexanone, thereby shortening the fire extinguishing time and reducing the battery temperature after fire extinguishing.

[0096] Furthermore, the applicant conducted a trial run of unfluorinated alumina nanosheets during its research and development. The unfluorinated alumina nanosheets agglomerated in perfluorohexane and also agglomerated with silica aerogel, causing severe solid-liquid dissociation of the fire extinguishing agent and rendering it unusable.

[0097] The fire extinguishing agent in this application also includes two additives: perfluoropolyether oil and core-shell SiO2@ammonium polyphosphate. The perfluoropolyether oil can inhibit reignition, while the core-shell SiO2@ammonium polyphosphate acts as a flame retardant enhancer. When used together, the two have a synergistic effect.

[0098] Based on this, it can be seen from Embodiments 1 and 6-8 of this application that: The extinguishing agent of Example 6 contained neither perfluoropolyether oil nor core-shell SiO2@ammonium polyphosphate; the extinguishing agent of Example 7 contained core-shell SiO2@ammonium polyphosphate but no perfluoropolyether oil; the extinguishing agent of Example 8 contained perfluoropolyether oil but no core-shell SiO2@ammonium polyphosphate.

[0099] In the fire extinguishing performance test results: The flame extinguishing time of Example 7 is shorter than that of Example 6, and the battery temperature after extinguishing the fire in Example 7 is lower than that in Example 6. The flame extinguishing time of Example 8 is shorter than that of Example 6, and Example 8 does not reignite in the condensate water wetting reignition test, while Examples 6 and 7 reignite in the condensate water wetting reignition test. The flame extinguishing time of Example 1 is shorter than that of Example 8, the battery temperature after extinguishing the fire in Example 1 is lower than that in Example 8, and Example 1 does not reignite in the condensate water wetting reignition test.

[0100] The reason is that in this application, the core-shell type SiO2@ammonium polyphosphate expands and unfolds to cover the surface when exposed to fire, isolating oxygen and adsorbing liquid electrolyte; the SiO2 shell reacts with HF to generate SiF4, reducing the release of corrosive gases; Perfluoropolyether oil can quickly spread on the surface of battery electrodes to form a self-healing insulating film, blocking plasma channels and preventing the chain reaction of insulation failure caused by "high temperature of electric arc leading to carbonization of the conductive path of the dielectric → secondary combustion and explosion". This enhances the fire extinguishing and protective effects. It also delays the release of oxygen from the positive electrode material and inhibits the chain reaction of reignition. The use of perfluoropolyether and silica aerogel powder together can delay the high-temperature decomposition of perfluoropolyether oil and provide long-lasting protection.

[0101] Furthermore, when both are used together, the expanded carbon layer is wetted by the perfluoropolyether oil, which further improves the oxygen isolation efficiency and fire extinguishing performance.

[0102] Other component ratios are also available for the extinguishing agent of this application, such as those in Examples 9 and 10. In the fire extinguishing performance test results of Examples 9 and 10, the flame extinguishing time is significantly shorter than that of Comparative Examples 1 and 2, and it has excellent anti-reignition performance. In the stability test results, its settling height ratio is small and the top solid phase retention rate is large.

[0103] Therefore, the mass fraction of the raw materials used in this application for the fire extinguishing agent is controlled as follows: 8-12 parts silica aerogel powder, 40-45 parts perfluorohexanone, 2-3 parts hyperbranched polysiloxane, 0.2-0.3 parts 18-crown-6 ether, 1.2-1.5 parts fluorinated alumina nanosheets, 2-3 parts perfluoropolyether oil, and 6-8 parts core-shell SiO2@ammonium polyphosphate. The resulting fire extinguishing agent can effectively extinguish fires on precision electrical components, leaves little residue, prevents reignition, and causes minimal damage to instruments and equipment, making it suitable for application in the electrical field.

[0104] Example 11 A fire extinguishing device includes a container and a release mechanism for releasing an extinguishing agent. The container contains an extinguishing agent, one of the extinguishing agents described in Examples 1-10. The release mechanism includes a nozzle, a spray pipe, a compressed nitrogen storage tank, and a connecting pipe. The compressed nitrogen storage tank has an on / off valve, the spray pipe connects the nozzle to the container, and the connecting pipe connects the container to the on / off valve.

[0105] When in use, open the on / off valve, compress nitrogen as propellant, and squeeze the extinguishing agent out of the nozzle.

[0106] The valve can be opened and closed manually, or it can be controlled to open by detecting sound waves above 120dB (such as electric arc explosions) using a sound wave sensor.

[0107] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of protection claimed by the present invention, they are protected by patent law.

Claims

1. An aerogel fire extinguishing agent for firefighting, characterized in that, The raw materials include the following parts by weight: 8-12 parts of silica aerogel powder 40-45 parts of perfluorohexanone 2-3 parts of hyperbranched polysiloxane 0.2-0.3 parts of 18-crown-6 ether 1.5 to 2 parts zinc molybdate, 0.8 to 1.2 parts nano cerium oxide.

2. The fire extinguishing agent for fire protection according to claim 1, characterized in that, Silica aerogels are fluorine-doped silica aerogels modified with tetraethoxyfluorosilane.

3. The fire extinguishing agent for fire protection according to claim 1, characterized in that, It also includes 1.2 to 1.5 parts of fluorinated alumina nanosheets.

4. The fire extinguishing agent for fire protection according to claim 1, characterized in that, The silica aerogel powder is hydrophobically modified with hexamethyldisilazane.

5. The fire extinguishing agent for fire protection according to claim 1, characterized in that, It also includes 2-3 parts of perfluoropolyether oil.

6. The fire extinguishing agent for fire protection according to claim 1, characterized in that, It also includes 6-8 parts of core-shell type SiO2@ammonium polyphosphate.

7. A fire extinguishing device, characterized in that, The device includes a container, a release mechanism, and a nozzle. The release mechanism includes a compressed nitrogen storage tank with an on / off valve connected to the container, and the nozzle is connected to the container. The container contains the fire-fighting aerogel extinguishing agent as described in any one of claims 1 to 6.

8. A method for releasing a fire extinguishing agent, characterized in that, Using the fire extinguishing device of claim 7, aim the nozzle at the fire source and open the opening and closing valve; the opening and closing valve can be opened manually or by detecting sound waves of 120dB or higher by a sound wave sensor to control the opening and closing valve to open.

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