A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, its preparation method and application

Abstract

The present invention relates to the technical field of fire extinguishing agents for lithium-ion batteries, and particularly to a non-ionic fine water mist heat runaway suppression fire extinguishing agent and its preparation method and application. The non-ionic fine water mist fire extinguishing agent comprises the following components in mass percentages: 5.0-15% of non-ionic surfactant, 0.3-0.5% of modified nanoparticles, 2.5-4.0% of bio-based thickener, 0.5-1.5% of flavonoid compounds, 15%-20% of organic solvent, and the balance being deionized water. The fine water mist fire extinguishing agent provided by the present invention uses a non-ionic surfactant, which can significantly reduce the surface tension of water, enabling the fine water mist to better wet the surface of the combustible, and adding modified nanoparticles, flavonoid compounds and bio-based thickener therein, achieving excellent flame retardancy and wettability, improving the overall performance of the fine water mist fire extinguishing agent, and the fire extinguishing agent composition contains neither inorganic salts nor fluorine, being green and environmentally friendly with high fire extinguishing efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium - ion battery fire extinguishing agents, and specifically relates to a non - ionic fine water mist heat - runaway suppressing fire extinguishing agent, its preparation method and application. Background Technique

[0002] Lithium - ion batteries have many advantages such as being green and environmentally friendly, having a high energy density, a low self - discharge rate, and being convenient to carry, and are widely used in fields such as electronic devices, electric vehicles, and energy storage systems, playing an important role in future scientific and technological innovation and industrial transformation. However, safety hazards cannot be ignored. Lithium - ion batteries are prone to thermal runaway after improper use, overcharging, short - circuiting, or being squeezed, punctured, or overheated, which can cause fires or even explosions, resulting in incalculable losses.

[0003] Fire - fighting measures, as the last line of defense for safety assurance, play a crucial role. Lithium - battery fires have become the focus of public attention due to their rapid occurrence and spread, continuous high temperature, and easy reignition. Therefore, the selected fire - extinguishing agent must have excellent cooling performance to effectively address these challenges. The fine water mist fire - extinguishing agent technology is a high - tech and environmentally friendly technology. By means of high pressure or special nozzles, water is atomized into fine water droplets with a diameter of no more than 400 μm. The tiny diameter causes the surface area of the fine water mist to increase sharply compared with the same volume of water, greatly improving the heat - exchange efficiency and achieving a good cooling effect. While absorbing heat, the fine water mist is rapidly vaporized, causing the volume to expand sharply, thereby reducing the oxygen concentration in the air and inhibiting the speed of the oxidation reaction during combustion, playing a suffocating role. However, when dealing with large - scale lithium - battery fires or other types of fires, a single fine water mist takes a long time to completely extinguish the flame. The small particle size of the fine water mist makes it difficult to penetrate the smoke and directly contact the battery with low efficiency, and a large amount of water is consumed during use. Its cooling and fire - extinguishing effect still needs to be improved.

[0004] In recent years, multiple research institutions at home and abroad have been committed to expanding the application scope of the water mist fire extinguishing technology and enhancing its effect. One of the technologies that has received much attention is adding additives to water mist to improve the fire extinguishing effect. The current additives can be mainly divided into two types, including inorganic salts and surfactants. However, the addition of inorganic salts will ionize in water, generating a large number of metal ions, which are likely to damage storage devices and lithium-ion batteries. Among the surfactants, fluorine-containing surfactants have good effects, but such substances have problems such as difficult degradation and potential harm to the environment. The existing patented technologies containing additives still have problems such as easy pollution and easy corrosion. For example, the Chinese patent with the publication number CN 104888397A records a water mist additive, its preparation method and application, in which alkaline earth metal salts, alkali metal salts and surfactants are used in the additive; the Chinese patent with the publication number CN 102657924A discloses that the formula of the additive contained in the water mist fire extinguishing agent is mainly fluorocarbon surfactants, alkali metal salts and heat-sensitive substances. An ideal water mist fire extinguishing agent should have a fast fire extinguishing speed and high fire extinguishing efficiency when suppressing the thermal runaway of lithium batteries, and at the same time should have characteristics such as being green and environmentally friendly and having little corrosion. However, the currently disclosed formula technologies cannot fully meet the above requirements well. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a green and environmentally friendly non-ionic water mist thermal runaway suppression fire extinguishing agent, its preparation method and application in view of the deficiencies existing in the prior art in the background art. Through testing, it can effectively suppress the thermal runaway of lithium batteries.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A non-ionic water mist thermal runaway suppression fire extinguishing agent comprises the following components by mass percentage: non-ionic surfactant 5.0 - 15%, modified nanoparticles 0.3 - 0.5%, bio-based thickener 2.5 - 4.0%, flavonoid compound 0.5 - 1.5%, organic solvent 15% - 20%, and the balance is deionized water. Current research shows that when a non-ionic surfactant is used as an additive to water mist, it can significantly reduce the surface tension of water, enabling the water mist to better wet the surface of the combustible, absorb heat faster and cool the combustion area. The low surface tension allows water droplets to be more evenly distributed and cover a larger area, and improves the wetting ability of water on the surface of lithium batteries, thereby helping the water mist to penetrate deeper into the interior of the combustible and improving the fire extinguishing effect.

[0008] Nanoparticles have a very high specific surface area and can rapidly absorb heat. When in contact with a flame, they can quickly absorb heat and disperse it, rapidly reducing the temperature in the combustion area; the high specific surface area can also accelerate the evaporation process of water droplets, forming more vapor layers, which helps to isolate oxygen and inhibit the combustion reaction; nanoparticles can also form a dense protective film on the surface of lithium batteries, blocking heat transfer and oxygen supply, forming a good physical barrier. However, nanoparticles tend to agglomerate, making it impossible for them to be evenly dispersed in the fine water mist system, thus affecting the fire extinguishing effect. Therefore, in the present invention, through modification, the nanoparticles have better hydrophilicity and dispersibility, enabling the water mist to be more evenly distributed on the combustible material, enhancing the wetting effect. The presence of non-ionic surfactants and organic solvents can form micelles around the modified nanoparticles, effectively preventing direct contact between the nanoparticles and reducing the agglomeration phenomenon caused by van der Waals forces and electrostatic forces, which enables the modified nanoparticles to maintain a uniformly distributed state in the fine water mist for a long time.

[0009] The bio-based thickeners used in the present invention belong to natural polysaccharides, and they can significantly improve the viscosity of the solution, reduce the water evaporation rate, and form a more stable and long-lasting water mist.

[0010] Although flavonoids are mostly used in the field of medical health, due to their unique chemical properties, they can be used as a type of natural flame retardant applicable to fine water mist fire extinguishing agents. Flavonoids have strong antioxidant properties and can scavenge free radicals generated during the combustion process, thereby interrupting the chain reaction and reducing the spread of the flame. By inhibiting free radicals, flavonoids can help reduce the secondary oxidation of materials after combustion and lower the possibility of re-ignition. However, flavonoids have a certain degree of hydrophobicity and are not easily directly soluble in water. Therefore, in the present invention, organic solvents are used to dissolve flavonoids, and the presence of the hydrophilic and hydrophobic ends of non-ionic surfactants enables flavonoids to be better dispersed in water.

[0011] Preferably, the nonionic surfactant is selected from any one of polycarbon alkyl glycoside 0810 (APG0810), polyoxyethylene sorbitan monooleate (Tween80), and polyoxyethylene sorbitan monolaurate (Tween20). As a nonionic surfactant, alkyl glycoside, in addition to having the common characteristics of nonionic surfactants, also has good compatibility, good foaming and good biodegradability. It can form a stable foam layer in lithium electronic battery fires, isolate oxygen, and help extinguish the flame. It is green and environmentally friendly, reducing the pollution of the fine water mist system to the environment. Tween80 and Tween20 both belong to polyoxyethylene sorbitan fatty acid esters, have good emulsification, solubilization, wetting and dispersing properties, and will produce brittle foam during use, which can also take away part of the heat and accelerate cooling. And it has good biodegradability and has little burden on the environment.

[0012] Preferably, the modified nanoparticles are modified nanosilicon dioxide; and the bio-based thickener is carrageenan or gum arabic. The surface-modified nanosilicon dioxide has better hydrophilicity and dispersibility, and can make the water mist more evenly distributed on the burning material, thereby enhancing the wetting effect. The presence of nanoparticles can increase the contact area between the water mist and the burning material, and help the water penetrate into the material through capillary action, thereby achieving a better fire extinguishing effect.

[0013] Preferably, the natural thickener is a flavonoid compound, specifically quercetin or apigenin; the organic solvent is any one of methanol, ethanol, ethyl acetate, and glacial acetic acid. Flavonoid compounds can decompose and form a stable carbon layer at high temperatures. This carbon layer can act as a physical barrier to prevent heat transfer and oxygen from entering the combustion area, thereby slowing down the combustion process. Quercetin and apigenin contain multiple phenolic hydroxyl groups, which can effectively remove active free radicals and reduce the combustion rate. At high temperatures, flavonoid compounds can also release some non-combustible gases, such as carbon dioxide, which dilute the concentration of combustible gases and further inhibit the spread of flames. Quercetin and apigenin are derived from natural plant extracts and have good biodegradability. The addition of organic solvents is used to dissolve hydrophobic flavonoid compounds so that they can be better dispersed in the fine water mist system.

[0014] As a general technical concept, Figure 1 As shown, the present invention also provides a method for preparing a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway, comprising the following steps:

[0015] Putting flavonoid compound powder into a reactor, adding an organic solvent and stirring for 20 to 40 minutes to dissolve the flavonoid compound; adjusting the pH value to 7.0 to 7.5 with an alkaline solution, and filtering to obtain a solution A;

[0016] Dissolve the non-ionic surfactant in a reactor containing deionized water; subsequently add the modified nanoparticles, and transfer the reactor to an ultrasonic processor for ultrasonic treatment; add the bio-based thickener premixed with cold water to the reactor, and stir to obtain Solution B;

[0017] Add the prepared Solution A to the obtained Solution B, and stir for 25 - 55 min simultaneously to make Solution A and Solution B fully mixed and uniform, obtaining an aqueous solution, which is the non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0018] Preferably, filter with a microporous filter membrane, and the pore size of the microporous filter membrane is 0.1 μm, 0.22 μm or 0.45 μm; the alkali solution is 0.1 M NaOH.

[0019] Preferably, the ultrasonic treatment time is 15 - 30 min.

[0020] Preferably, the preparation method of the modified nanoparticles comprises the following steps:

[0021] Disperse the nano-silica powder in absolute ethanol, add an acid to adjust the pH to 3.0 - 4.0, perform ultrasonic treatment for 10 - 30 min, continue to add a silane coupling agent, and stir for 2 - 4 hours to make the silane coupling agent react fully with the nano-silica; after the reaction is completed, filter, wash, and dry to obtain the modified nanoparticles.

[0022] Preferably, the acid is 0.1 M dilute hydrochloric acid, and the silane coupling agent is γ-aminopropyltriethoxysilane; the mass ratio of the nanoparticles to the silane coupling agent is 1:0.05 - 0.4; the drying temperature is 60 - 80 °C, and the drying time is 4 - 12 hours; the particle size of the modified nano-silica is 25 - 75 nm.

[0023] As a general technical concept, the present invention also provides the application of the non-ionic fine water mist fire extinguishing agent for suppressing the thermal runaway of lithium-ion batteries.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The non-ionic surfactant significantly reduces the surface tension of water, enabling the fine water mist to better moisten the surface of the combustible, and helping to form finer and more uniform water droplets; the modified nanoparticles have good dispersibility, and after being mixed with the non-ionic surfactant, the non-ionic surfactant can form micelles around the modified nanoparticles, effectively preventing direct contact between the nanoparticles, reducing the agglomeration phenomenon caused by van der Waals forces and electrostatic forces, making the nanoparticles more uniformly wrapped in each water droplet of the fine water mist, and making the fine water mist uniformly wrapped with modified nanoparticles not easily vaporized and more likely to pass through the flame to reach the combustion center. The addition of the bio-based thickener increases the viscosity of the fine water mist system, making the water droplets of the fine water mist wrapped with nanoparticles more viscous, thereby prolonging the residence time on the surface of the lithium battery and enabling the fine water mist to absorb heat more effectively. The flavonoid compound, as a natural flame retardant, forms a carbon layer outside the small water droplets wrapped with nanoparticles, serving as a physical barrier to prevent heat transfer and oxygen from entering the combustion area, thereby slowing down the combustion process. The fine water mist fire extinguishing agent provided by the present invention can extinguish fires efficiently and at high speed. In addition, the fine water mist fire extinguishing agent does not contain inorganic salts or fluorine, is stable, uniform, green and environmentally friendly, which is beneficial to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a preparation flow chart of the non-ionic fine water mist fire extinguishing agent. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the technical solutions in the embodiments of the present invention or the prior art will be described in detail below. The described embodiments are only partial embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention. The present invention will be further described below with specific embodiments.

[0027] In the present invention, the non-ionic surfactant, nanoparticles, flavonoid compound, organic solvent and bio-based thickener are all existing products.

[0028] The non-ionic surfactant is purchased from Nagase Co., Ltd.

[0029] The nanoparticle powder is purchased from Shandong Delan Chemical Co., Ltd.

[0030] The flavonoid compound is purchased from Gansu Yishengxiang Biotechnology Co., Ltd.

[0031] The organic solvent is purchased from Sinopharm Group.

[0032] The bio-based thickener is purchased from Shanghai Macklin Biochemical Co., Ltd.

[0033] Example 1

[0034] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising components in the following mass percentages: 10% of non-ionic surfactant APG0810, 0.5% of modified nano-silica, 0.5% of apigenin, 15% of ethanol, 2.5% of arabic gum, and the balance being deionized water.

[0035] The specific preparation steps are as follows:

[0036] (1) Add ethanol and apigenin to a reactor, stir with a magnetic stirrer for 20 min to fully dissolve the apigenin; add 0.1 M NaOH to adjust the pH value to 7.0, and then filter through a 0.22 μm microporous membrane to obtain an apigenin aqueous solution;

[0037] (2) Disperse nano-silica powder with a particle size of 45 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.0, perform ultrasonic treatment for 15 min, continue to add 0.1% (by mass) of silane coupling agent γ-aminopropyltriethoxysilane, and stir for 4 hours to fully react γ-aminopropyltriethoxysilane with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 75 °C for 8 h to obtain modified nano-silica powder;

[0038] (3) Dissolve non-ionic surfactant APG0810 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 20 min; add arabic gum pre-mixed with cold water to the reactor and stir for 45 min;

[0039] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir simultaneously for 50 min to make the solution evenly mixed, and the obtained aqueous solution is the non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0040] Example 2

[0041] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising components in the following mass percentages: 15% of non-ionic surfactant APG0810, 0.4% of modified nano-silica, 1.0% of apigenin, 18% of ethyl acetate, 3.5% of carrageenan, and the balance being deionized water.

[0042] The specific preparation steps are as follows:

[0043] (1) Add ethyl acetate and apigenin to a reactor, stir with a magnetic stirrer for 25 min to fully dissolve the apigenin; add 0.1 M NaOH to adjust the pH value to 7.5, and then filter through a 0.1 μm microporous membrane to obtain an apigenin aqueous solution;

[0044] (2) Disperse the nano-silica powder with a particle size of 50 nm in anhydrous ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 4.0, perform ultrasonic treatment for 20 min, then continue to add the silane coupling agent γ-aminopropyltriethoxysilane with a mass ratio of 0.16%, and stir for 3.5 hours to fully react γ-aminopropyltriethoxysilane with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 60 °C for 6 h to obtain the modified nano-silica powder;

[0045] (3) Dissolve the non-ionic surfactant APG0810 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 30 min; add the carrageenan pre-mixed with cold water to the reactor and stir for 25 min;

[0046] (4) Add the prepared aqueous apigenin solution to the solution mixed in step (3), and stir for 55 min at the same time to make the solution mix evenly, and the obtained aqueous solution is the non-ionic fine water mist heat runaway extinguishing agent.

[0047] Example 3

[0048] A non-ionic fine water mist heat runaway extinguishing agent, comprising the following components in mass percentages: 5% of non-ionic surfactant APG0810, 0.3% of modified nano-silica, 1.5% of quercetin, 20% of methanol, 4% of arabic gum, and the balance is deionized water.

[0049] The specific preparation steps are as follows:

[0050] (1) Add methanol and quercetin to the reactor, and stir with a magnetic stirrer for 30 min to fully dissolve quercetin; add 0.1 M NaOH to adjust the pH value to 7.3, and then filter with a 0.45 μm microporous filter membrane to obtain an aqueous quercetin solution;

[0051] (2) Disperse the nano-silica powder with a particle size of 25 nm in anhydrous ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.5, perform ultrasonic treatment for 30 min, then continue to add the silane coupling agent γ-aminopropyltriethoxysilane with a mass ratio of 0.015%, and stir for 2 hours to fully react γ-aminopropyltriethoxysilane with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 80 °C for 5 h to obtain the modified nano-silica powder;

[0052] (3) Dissolve the nonionic surfactant APG0810 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 30 min; add the gum arabic premixed with cold water to the reactor and stir for 30 min;

[0053] (4) Add the prepared quercetin aqueous solution to the well-mixed solution in step (3), and stir for 25 min simultaneously to make the solution evenly mixed. The obtained aqueous solution is the nonionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0054] Example 4

[0055] A nonionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising the following components by mass percentage: 8% of nonionic surfactant APG0810, 0.35% of modified nano-silica, 0.8% of quercetin, 16% of glacial acetic acid, 2.7% of carrageenan, and the balance being deionized water.

[0056] The specific preparation steps are as follows:

[0057] (1) Add glacial acetic acid and quercetin to a reactor, stir with a magnetic stirrer for 24 min to fully dissolve quercetin; add 0.1 M NaOH to adjust the pH value to 7.1, and then filter with a 0.22 μm microporous filter membrane to obtain a quercetin aqueous solution;

[0058] (2) Disperse the nano-silica powder with a particle size of 75 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.2, perform ultrasonic treatment for 26 min, continue to add 0.028% of the silane coupling agent γ-aminopropyltriethoxysilane by mass, and stir for 2 hours to make γ-aminopropyltriethoxysilane fully react with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 72 °C for 12 h to obtain the modified nano-silica powder;

[0059] (3) Dissolve the nonionic surfactant APG0810 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 30 min; add the carrageenan premixed with cold water to the reactor and stir for 50 min;

[0060] (4) Add the prepared quercetin aqueous solution to the well-mixed solution in step (3), and stir for 25 min simultaneously to make the solution evenly mixed. The obtained aqueous solution is the nonionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0061] Example 5

[0062] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising components in the following mass percentages: 6% of non-ionic surfactant Tween80, 0.45% of modified nano-silica, 0.6% of apigenin, 16% of ethanol, 2.8% of arabic gum, and the balance being deionized water.

[0063] The specific preparation steps are as follows:

[0064] (1) Add ethanol and apigenin to a reactor, stir with a magnetic stirrer for 29 min to fully dissolve the apigenin; add 0.1 M NaOH to adjust the pH value to 7.0, and then filter through a 0.22 μm microporous membrane to obtain an apigenin aqueous solution;

[0065] (2) Disperse nano-silica powder with a particle size of 50 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.5, perform ultrasonic treatment for 25 min, continue to add 0.09% by mass of silane coupling agent γ-aminopropyltriethoxysilane, and stir for 3 hours to fully react γ-aminopropyltriethoxysilane with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 60 °C for 10 h to obtain modified nano-silica powder;

[0066] (3) Dissolve non-ionic surfactant Tween80 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 20 min; add arabic gum premixed with cold water to the reactor and stir for 35 min;

[0067] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir for 40 min at the same time to make the solution evenly mixed, and the obtained aqueous solution is the non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0068] Example 6

[0069] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising components in the following mass percentages: 13% of non-ionic surfactant Tween80, 0.48% of modified nano-silica, 1.2% of apigenin, 17% of ethyl acetate, 4% of carrageenan, and the balance being deionized water.

[0070] The specific preparation steps are as follows:

[0071] (1) Add ethyl acetate and apigenin to a reactor, stir with a magnetic stirrer for 40 min to fully dissolve the apigenin; add 0.1 M NaOH to adjust the pH value to 7.2, and then filter through a 0.45 μm microporous membrane to obtain an apigenin aqueous solution;

[0072] (2) Disperse nano-silica powder with a particle size of 65 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.0, perform ultrasonic treatment for 16 min, then continue to add silane coupling agent γ-aminopropyltriethoxysilane with a mass ratio of 0.048%, and stir for 2.5 hours to make γ-aminopropyltriethoxysilane react fully with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 68 °C for 9 h to obtain modified nano-silica powder;

[0073] (3) Dissolve non-ionic surfactant Tween80 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 28 min; add carrageenan pre-mixed with cold water to the reactor and stir for 32 min;

[0074] (4) Add the prepared aqueous apigenin solution to the solution mixed in step (3), and stir simultaneously for 46 min to make the solution mix evenly, and the obtained aqueous solution is a non-ionic fine water mist heat runaway extinguishing agent.

[0075] Example 7

[0076] A non-ionic fine water mist heat runaway extinguishing agent, comprising the following components by mass percentage: 7% of non-ionic surfactant Tween80, 0.34% of modified nano-silica, 1.3% of quercetin, 13% of methanol, 3.6% of arabic gum, and the balance is deionized water.

[0077] The specific preparation steps are as follows:

[0078] (1) Add methanol and quercetin to a reactor, stir with a magnetic stirrer for 36 min to fully dissolve quercetin; add 0.1 M NaOH to adjust the pH value to 7.4, and then filter with a 0.1 μm microporous membrane to obtain an aqueous quercetin solution;

[0079] (2) Disperse nano-silica powder with a particle size of 54 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.3, perform ultrasonic treatment for 18 min, then continue to add silane coupling agent γ-aminopropyltriethoxysilane with a mass ratio of 0.017%, and stir for 2.6 hours to make γ-aminopropyltriethoxysilane react fully with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 71 °C for 4 h to obtain modified nano-silica powder;

[0080] (3) Dissolve the non-ionic surfactant Tween 80 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 22 min; add the gum arabic premixed with cold water to the reactor and stir for 28 min;

[0081] (4) Add the prepared aqueous quercetin solution to the solution mixed in step (3), and stir for 46 min simultaneously to make the solution evenly mixed. The obtained aqueous solution is the non-ionic fine water mist heat runaway inhibitor extinguishing agent.

[0082] Example 8

[0083] A non-ionic fine water mist heat runaway inhibitor extinguishing agent, comprising the following components in mass percentage: 9% of non-ionic surfactant Tween 80, 0.42% of modified nano-silica, 0.7% of quercetin, 14% of glacial acetic acid, 3.2% of carrageenan, and the balance is deionized water.

[0084] The specific preparation steps are as follows:

[0085] (1) Add glacial acetic acid and quercetin to a reactor, stir with a magnetic stirrer for 36 min to fully dissolve quercetin; add 0.1 M NaOH to adjust the pH value to 7.2, and then filter with a 0.45 μm microporous membrane to obtain an aqueous quercetin solution;

[0086] (2) Disperse the nano-silica powder with a particle size of 32 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.8, perform ultrasonic treatment for 18 min, continue to add 0.126% by mass of the silane coupling agent γ-aminopropyltriethoxysilane, and stir for 2.8 hours to make γ-aminopropyltriethoxysilane fully react with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 67 °C for 7 h to obtain the modified nano-silica powder;

[0087] (3) Dissolve the non-ionic surfactant Tween 80 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 19 min; add the carrageenan premixed with cold water to the reactor and stir for 42 min;

[0088] (4) Add the prepared aqueous quercetin solution to the solution mixed in step (3), and stir for 48 min simultaneously to make the solution evenly mixed. The obtained aqueous solution is the non-ionic fine water mist heat runaway inhibitor extinguishing agent.

[0089] Example 9

[0090] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising components in the following mass percentages: 11% of non-ionic surfactant Tween20, 0.5% of modified nano-silica, 0.9% of apigenin, 18% of ethanol, 2.9% of arabic gum, and the balance being deionized water.

[0091] The specific preparation steps are as follows:

[0092] (1) Add ethanol and apigenin to a reactor, stir with a magnetic stirrer for 34 min to fully dissolve the apigenin; add 0.1 M NaOH to adjust the pH value to 7.4, and then filter with a 0.45 μm microporous membrane to obtain an apigenin aqueous solution;

[0093] (2) Disperse nano-silica powder with a particle size of 40 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.8, perform ultrasonic treatment for 17 min, continue to add 0.1% (by mass) of silane coupling agent γ-aminopropyltriethoxysilane, and stir for 3.5 hours to fully react γ-aminopropyltriethoxysilane with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 67 °C for 11 h to obtain the modified nano-silica powder;

[0094] (3) Dissolve non-ionic surfactant Tween20 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 24 min; add arabic gum pre-mixed with cold water to the reactor and stir for 47 min;

[0095] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir simultaneously for 54 min to make the solution evenly mixed, and the obtained aqueous solution is the non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0096] Example 10

[0097] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising components in the following mass percentages: 14% of non-ionic surfactant Tween20, 0.48% of modified nano-silica, 1.1% of apigenin, 17% of ethyl acetate, 3.4% of carrageenan, and the balance being deionized water.

[0098] The specific preparation steps are as follows:

[0099] (1) Add ethyl acetate and apigenin to a reactor, stir with a magnetic stirrer for 26 min to fully dissolve the apigenin; add 0.1 M NaOH to adjust the pH value to 7.1, and then filter with a 0.22 μm microporous membrane to obtain an apigenin aqueous solution;

[0100] (2) Disperse the nano-silica powder with a particle size of 38 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.2, perform ultrasonic treatment for 21 min, then continue to add the silane coupling agent γ-aminopropyltriethoxysilane with a mass ratio of 0.096%, and stir for 2.4 hours to make γ-aminopropyltriethoxysilane react fully with the nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 78 °C for 5 h to obtain the modified nano-silica powder;

[0101] (3) Dissolve the non-ionic surfactant Tween20 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 16 min; add the carrageenan premixed with cold water to the reactor and stir for 37 min;

[0102] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir simultaneously for 43 min to make the solution mix evenly, and the obtained aqueous solution is the non-ionic fine water mist heat runaway extinguishing agent.

[0103] Example 11

[0104] A non-ionic fine water mist heat runaway extinguishing agent, comprising the following components in mass percentage: 6% of non-ionic surfactant Tween20, 0.33% of modified nano-silica, 1.4% of quercetin, 16% of methanol, 3.4% of arabic gum, and the balance is deionized water.

[0105] The specific preparation steps are as follows:

[0106] (1) Add methanol and quercetin to the reactor, and stir with a magnetic stirrer for 36 min to fully dissolve quercetin; add 0.1 M NaOH to adjust the pH value to 7.3, and then filter with a 0.45 μm microporous filter membrane to obtain the quercetin aqueous solution;

[0107] (2) Disperse the nano-silica powder with a particle size of 27 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.6, perform ultrasonic treatment for 21 min, then continue to add the silane coupling agent γ-aminopropyltriethoxysilane with a mass ratio of 0.033%, and stir for 3.9 hours to make γ-aminopropyltriethoxysilane react fully with the nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 74 °C for 6.5 h to obtain the modified nano-silica powder;

[0108] (3) Dissolve the non-ionic surfactant Tween 20 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 17 min; add the gum arabic premixed with cold water to the reactor and stir for 34 min;

[0109] (4) Add the prepared aqueous quercetin solution to the solution mixed in step (3), and stir for 49 min simultaneously to make the solution uniformly mixed. The obtained aqueous solution is the non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0110] Example 12

[0111] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, comprising the following components by mass percentage: 12% of non-ionic surfactant Tween 20, 0.35% of modified nano-silica, 0.9% of quercetin, 18% of glacial acetic acid, 3.1% of carrageenan, and the balance is deionized water.

[0112] The specific preparation steps are as follows:

[0113] (1) Add glacial acetic acid and quercetin to a reactor, stir with a magnetic stirrer for 36 min to fully dissolve quercetin; add 0.1 M NaOH to adjust the pH value to 7.5, and then filter with a 0.1 μm microporous filter membrane to obtain an aqueous quercetin solution;

[0114] (2) Disperse the nano-silica powder with a particle size of 46 nm in absolute ethanol, add 0.1 M dilute hydrochloric acid to adjust the pH to 3.7, perform ultrasonic treatment for 26 min, continue to add 0.028% by mass of the silane coupling agent γ-aminopropyltriethoxysilane, and stir for 3.5 h to make γ-aminopropyltriethoxysilane fully react with nano-silica; after the reaction is completed, filter, wash, and dry in an oven at 64 °C for 8.5 h to obtain the modified nano-silica powder;

[0115] (3) Dissolve the non-ionic surfactant Tween 20 in a reactor containing deionized water, add the modified nano-silica powder, and transfer the reactor to an ultrasonic processor for ultrasonic treatment for 24 min; add the carrageenan premixed with cold water to the reactor and stir for 54 min;

[0116] (4) Add the prepared aqueous quercetin solution to the solution mixed in step (3), and stir for 40 min simultaneously to make the solution uniformly mixed. The obtained aqueous solution is the non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

[0117] Comparative Example 1

[0118] A fine water mist heat runaway extinguishing agent, except that it does not contain the component non-ionic surfactant, the remaining steps are the same as those in Example 1.

[0119] Comparative Example 2

[0120] A non-ionic fine water mist heat runaway extinguishing agent, except that it does not contain modified nanoparticles, the remaining steps are the same as those in Example 1.

[0121] Comparative Example 3

[0122] A non-ionic fine water mist heat runaway extinguishing agent, except that it does not contain flavonoids, the remaining steps are the same as those in Example 1.

[0123] Comparative Example 4

[0124] A non-ionic fine water mist heat runaway extinguishing agent, except that it does not contain bio-based thickener, the remaining steps are the same as those in Example 1.

[0125] Comparative Example 5

[0126] A pure fine water mist heat runaway extinguishing agent.

[0127] Comparative Example 6

[0128] Blank experiment, without using any extinguishing agent.

[0129] Select the non-ionic fine water mist heat runaway extinguishing agents prepared in Examples 1-12 and the heat runaway extinguishing agents prepared in Comparative Examples 1-6 for testing.

[0130] In the implementation process of the present invention, at room temperature, the lithium battery is closely attached to a heating rod of the same size without gaps to ensure that the battery can be heated evenly. The 18650-type ternary lithium-ion battery INR18650-26E is selected, with a nominal capacity of 2.6 Ah and a nominal voltage of 3.65 V. In order to compare the suppression effects of fine water mist on lithium battery fires in different modes, each group of battery samples is charged at a constant current of 1 A until the battery reaches the maximum dangerous state of thermal runaway. The power of the heating rod is selected according to GB / T 36276-2023, and a heating power of 120 W is selected to induce heating of the lithium battery. Once thermal runaway starts, the heating mode is immediately turned off. The fine water mist nozzle is set 20 cm directly above the lithium battery, and the pressure of the nozzle spray is set to 1.5 MPa, and the spray angle is 90°.

[0131] The non-ionic fine water mist heat runaway suppressants prepared in Examples 1-12 and the heat runaway suppressants prepared in Comparative Examples 1-6 were loaded into the fine water mist system. A 120-W heating rod was used to slowly heat the lithium-ion battery. When the lithium battery experienced thermal runaway and produced a jet flame, the fine water mist system was turned on and spraying continued until the temperature of the lithium battery dropped below 50°C. The experimental data recorded are shown in Table 1.

[0132] Table 1 Performance test results of the fine water mist fire suppressants prepared in Examples 1-12 and Comparative Examples 1-5

[0133]

[0134] The initial temperature of thermal runaway reflects the temperature threshold at which the fine water mist fire suppressant begins to function in a fire environment, reflecting the sensitivity of the fine water mist fire suppressant. The determination of the highest temperature characterizes the most severe degree reached by the thermal runaway of the lithium-ion battery. The lower the highest temperature, the stronger the ability of the fine water mist fire suppressant to suppress heat during the fire extinguishing process. The maximum cooling rate is a key indicator for measuring the cooling effect of the fine water mist fire suppressant. A higher cooling rate means that the fine water mist can quickly absorb heat, rapidly lower the temperature in the fire area, and thus effectively suppress the spread of the fire. Generally, it is considered that when the temperature of the lithium battery drops below 50°C, the thermal runaway behavior can be effectively controlled. Therefore, in the present invention, the time required to drop to 50°C is used as a standard for measuring the performance of the fire suppressant. The shorter the time required to drop to 50°C, the faster the fire extinguishing speed of the fire suppressant.

[0135] As shown in Table 1, compared with Comparative Example 6 where no fire extinguishing operation was carried out, the initial temperature of thermal runaway in Examples 1-12 could be controlled below 190°C, indicating that the non-ionic fine water mist heat runaway suppressant provided by the present invention can effectively prevent thermal runaway; the highest temperatures in Examples 1-12 were all below 630°C, lower than 773.8°C in Comparative Example 6. Among them, Example 1 could lower the highest temperature to 325.8°C, and the highest temperature was significantly reduced, indicating that it can effectively control the development of the fire; the maximum cooling rates in Examples 1-12 could reach up to 15.6°C / s at most and 2.45°C / s at least, all higher than those in each comparative example; the time required for Examples 1-12 to drop to 50°C was at most 405 s and at least 136 s, significantly faster than those in each comparative example.

[0136] All indicators of Example 1 were better than those of Comparative Example 1 without a non-ionic surfactant because the non-ionic surfactant has a good wetting effect, can significantly reduce the surface tension of water, make the fine water mist easier to disperse into smaller droplets, can better wet the surface of the combustible, absorb heat faster and cool the combustion area.

[0137] In Example 1, all indicators are superior to Comparative Example 2 without modified nanoparticles because the modified nano-silica has better dispersibility, enabling it to be evenly dispersed in the fine water mist droplets, making the fine water mist uniformly coated with modified nanoparticles not easily vaporized and more likely to pass through the flame to reach the combustion center.

[0138] In Example 1, all indicators are superior to Comparative Example 3 without flavonoid compounds. Since flavonoid compounds, as a natural flame retardant, have strong antioxidant properties and can scavenge free radicals generated during combustion, thereby interrupting the chain reaction and reducing the spread of the flame. By inhibiting free radicals, flavonoid compounds can help reduce the secondary oxidation of materials after combustion and lower the possibility of re-ignition.

[0139] In Example 1, all indicators are superior to Comparative Example 4 without bio-based thickeners because bio-based thickeners belong to natural polysaccharides, which can significantly improve the viscosity of the solution, reduce the water evaporation rate, and form a more stable and lasting water mist.

[0140] In summary, the non-ionic thermal runaway inhibitor fire extinguishing agent provided by the present invention in Examples 1 to 12 has a short fire extinguishing time, a fast fire extinguishing speed, a high fire extinguishing efficiency, is not likely to cause secondary injuries during the fire extinguishing process, and is green and environmentally friendly.

[0141] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, characterized in that, Comprising components in the following mass percentages: non-ionic surfactant 5.0 - 15%, modified nanoparticles 0.3 - 0.5%, bio-based thickener 2.5 - 4.0%, flavonoid compound 0.5 - 1.5%, organic solvent 15% - 20%, and the balance being deionized water; the non-ionic surfactant is selected from any one of multi-carbon alkyl glycoside 0810, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan monolaurate; the modified nanoparticles are modified nano-silica; the bio-based thickener is carrageenan or gum arabic; the flavonoid compound is quercetin or apigenin; the organic solvent is any one of methanol, ethanol, ethyl acetate, and glacial acetic acid; the preparation method of the modified nanoparticles is as follows: dispersing nano-silica powder in absolute ethanol, adding an acid to adjust the pH to 3.0 - 4.0, performing ultrasonic treatment for 10 - 30 min, then adding a silane coupling agent and stirring for 2 - 4 hours to make the silane coupling agent react fully with the nano-silica; after the reaction is completed, filtering, washing, and drying to obtain the modified nanoparticles.

2. The preparation method of a non-ionic fine water mist heat runaway suppressing fire extinguishing agent according to claim 1, characterized in that, Comprising the following steps: Putting the flavonoid compound powder into a reactor, adding an organic solvent and stirring for 20 - 40 min to dissolve the flavonoid compound; adjusting the pH value to 7.0 - 7.5 with an alkali solution, and filtering to obtain solution A; Dissolving the non-ionic surfactant in a reactor containing deionized water; then adding the modified nanoparticles, and transferring the reactor to an ultrasonic processor for ultrasonic treatment; Adding the bio-based thickener premixed with cold water into the reactor, and stirring to obtain solution B; Adding the prepared solution A into the obtained solution B, and stirring simultaneously for 25 - 55 min to make solution A and solution B mix evenly, obtaining an aqueous solution, which is a non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway.

3. The preparation method of a non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway according to claim 2, characterized in that, Filtering with a microporous filter membrane, the pore size of the microporous filter membrane being 0.1 μm, 0.22 μm, or 0.45 μm; the alkali solution being 0.1 M NaOH.

4. The preparation method of a non-ionic fine water mist heat runaway suppressant according to claim 2, characterized in that, The ultrasonic time is 15 - 30 min.

5. The preparation method of a non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway according to claim 2, characterized in that, The acid is 0.1 M dilute hydrochloric acid, the silane coupling agent is γ-aminopropyltriethoxysilane; the mass ratio of the nanoparticles to the silane coupling agent is 1:0.05 - 0.4; the drying temperature is 60 - 80 °C, and the drying time is 4 - 12 hours; the particle size of the modified nano-silica is 25 - 75 nm.

6. The application of the nonionic fine water mist fire extinguishing agent for suppressing thermal runaway according to claim 1, wherein For suppressing thermal runaway of lithium-ion batteries.

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