Non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway as well as preparation method and application of non-ionic fine water mist fire extinguishing agent

Abstract

The invention relates to the technical field of lithium ion battery fire extinguishing agents, in particular to a nonionic fine water mist fire extinguishing agent for inhibiting thermal runaway and a preparation method and application thereof.The nonionic fine water mist fire extinguishing agent comprises, by mass, 5.0-15% of a nonionic surfactant, 0.3-0.5% of modified nano-particles, 2.5-4.0% of a bio-based thickening agent, 0.1-0.5% of a defoaming agent and the balance water. 0.5-1.5% of a flavonoid compound, 15-20% of an organic solvent and the balance of deionized water. According to the water mist fire extinguishing agent provided by the invention, the nonionic surfactant is used, the surface tension of water can be remarkably reduced, so that water mist can better wet the surface of a comburent, and the modified nanoparticles, the flavonoid compounds and the bio-based thickening agent are added, so that excellent flame retardance and wettability are realized; and the components of the water mist fire extinguishing agent do not contain inorganic salts or fluorine, so that the water mist fire extinguishing agent is green, environmentally friendly and high in fire extinguishing efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of fire extinguishing agents for lithium electronic battery fires, and in particular, relates to a non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, and a preparation method and application thereof. Background Art

[0002] As a green and environmentally friendly, high energy density, low self-discharge rate, easy to carry and many other advantages, lithium-ion batteries are widely used in electronic equipment, electric vehicles, energy storage systems and other fields, playing an important role in future technological innovation and industrial transformation. However, safety hazards cannot be ignored. Lithium-ion batteries are prone to thermal runaway after improper use, overcharging, short circuit, or extrusion, puncture, and overheating, which can cause fires or even explosions, causing incalculable losses.

[0003] Firefighting measures play a vital role as the last line of defense for safety. Lithium battery fires have become the focus of public attention due to their rapid occurrence and spread, continuous high temperature and easy re-ignition. Therefore, the selected fire extinguishing agent must have excellent cooling performance to effectively cope with these challenges. Fine water mist fire extinguishing agent technology is a high-tech and environmentally friendly technology. It uses high pressure or special nozzles to atomize water into fine water droplets with a diameter of no more than 400μm. The tiny diameter makes the surface area of ​​fine water mist increase dramatically compared with the same volume of water, which greatly improves the heat exchange efficiency and has a good cooling effect. Fine water mist absorbs heat and is quickly vaporized, causing the volume to expand rapidly, thereby reducing the oxygen concentration in the air, inhibiting the speed of the oxidation reaction in the combustion, and 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 fine water mist has a small particle size and is difficult to penetrate the smoke. The direct contact with the battery is inefficient and consumes a lot of water during use. Its cooling and fire extinguishing effect still needs to be improved.

[0004] In recent years, many research institutions at home and abroad have been committed to expanding the application scope of fine water mist fire extinguishing technology and improving its effect. One of the technologies that has attracted much attention is to add additives to fine water mist to improve the fire extinguishing effect. Today's additives can be mainly divided into two types, including inorganic salts and surfactants. However, the addition of inorganic salts will ionize in water to produce a large number of metal ions, which are easy to damage storage devices and lithium-ion batteries; fluorine-containing surfactants in surfactants have good effects, but these substances are difficult to degrade and have potential harm to the environment. The existing patented technology containing additives still has problems such as easy pollution and corrosion. For example, the Chinese patent with publication number CN 104888397A records a fine water mist additive and its preparation method and application, in which alkaline earth metal salts, alkali metal salts and surfactants are used in the additives; the Chinese patent with publication number CN 102657924A discloses that the formula of the additives contained in the fine 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 fast fire extinguishing speed and high fire extinguishing efficiency when suppressing thermal runaway of lithium batteries. It should also be green, environmentally friendly, and less corrosive. However, the currently available formulation technology cannot fully meet the above requirements. 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 fine water mist fire extinguishing agent for inhibiting thermal runaway and its preparation method and application, which can effectively inhibit thermal runaway of lithium batteries according to tests.

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

[0007] A non-ionic water mist fire extinguishing agent for suppressing thermal runaway includes the following components in percentage by mass: 5.0-15% non-ionic surfactant, 0.3-0.5% modified nanoparticles, 2.5-4.0% bio-based thickener, 0.5-1.5% flavonoids, 15%-20% organic solvent, and the balance is deionized water. Current research shows that when non-ionic surfactants are used as additives to water mist, they can significantly reduce the surface tension of water, allowing the water mist to better wet the surface of the burning object, absorb heat faster and cool the burning area. 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 deeply into the burning object and improve the fire extinguishing effect.

[0008] Nanoparticles have a very high specific surface area and can quickly absorb heat. When in contact with flames, they can quickly absorb and disperse heat to quickly reduce the temperature of the combustion area. The high specific surface area can also accelerate the evaporation process of water droplets, forming more steam 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 to prevent heat transfer and oxygen supply, forming a good physical barrier, but nanoparticles are prone to agglomeration, which makes it impossible to evenly disperse in the fine water mist system, thereby affecting the fire extinguishing effect. Because the present invention makes the nanoparticles have better hydrophilicity and dispersibility through modification, the water mist can be more evenly distributed on the burning material, enhancing the wetting effect, and the presence of non-ionic surfactants and organic solvents can form micelles around the modified nanoparticles, effectively preventing direct contact between nanoparticles and reducing the agglomeration phenomenon caused by van der Waals forces and electrostatic forces, which enables the modified nanoparticles to maintain a uniform distribution in the fine water mist for a long time.

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

[0010] Although flavonoids are mostly used in the medical and health field, they can be used as a natural flame retardant suitable for fine water mist fire extinguishing agents due to their unique chemical properties. Flavonoids have strong antioxidant properties and can remove free radicals generated during the combustion process, thereby interrupting the chain reaction and reducing the spread of flames. By inhibiting free radicals, flavonoids can help reduce the secondary oxidation of materials after combustion and reduce the possibility of re-ignition. However, flavonoids have a certain hydrophobicity and are not easily directly soluble in water, so the present invention uses an organic solvent to dissolve flavonoids, and the presence of the hydrophilic end and the hydrophobic end of the non-ionic surfactant 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] The nonionic surfactant is dissolved in a reactor containing deionized water; the modified nanoparticles are then added, and the reactor is transferred to an ultrasonic processor for ultrasonic treatment; the bio-based thickener pre-mixed with cold water is added to the reactor and stirred to obtain a solution B;

[0017] The prepared solution A is added to the obtained solution B, and stirred for 25 to 55 minutes to fully mix the solution A and the solution B to obtain an aqueous solution, which is a non-ionic fine water mist thermal runaway suppression fire extinguishing agent.

[0018] Preferably, filtration is performed using a microporous membrane, the pore size of which is 0.1 μm, 0.22 μm or 0.45 μm; and the alkaline solution is 0.1 M NaOH.

[0019] Preferably, the ultrasonic time is 15 to 30 minutes.

[0020] Preferably, the method for preparing the modified nanoparticles comprises the following steps:

[0021] Nano-silicon dioxide powder is dispersed in anhydrous ethanol, acid is added thereto to adjust the pH to 3.0-4.0, ultrasonic treatment is performed for 10-30 minutes, and silane coupling agent is continuously added, and stirring is performed for 2-4 hours to allow the silane coupling agent and nano-silicon dioxide to fully react; after the reaction is completed, filtering, washing and drying are performed to obtain modified nano-particles.

[0022] Preferably, the acid is 0.1M 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 25-75nm.

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

[0024] Compared with the prior art, the present invention has the following beneficial effects: the nonionic surfactant significantly reduces the surface tension of water, so that the fine water mist can better wet the surface of the burning object and help form finer and more uniform water droplets; the modified nanoparticles have good dispersibility, and after mixing with the nonionic surfactant, the nonionic surfactant can form micelles around the modified nanoparticles, effectively preventing direct contact between the nanoparticles, reducing the agglomeration phenomenon caused by van der Waals force and electrostatic force, so that the nanoparticles are more evenly wrapped in each drop of fine water mist, so that the fine water mist uniformly wrapping the modified nanoparticles is not easy to be vaporized, and it is easier 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 fine water mist droplets wrapping the nanoparticles more viscous, thereby extending the residence time on the surface of the lithium battery, so that the fine water mist can absorb heat more effectively. Flavonoid compounds, as natural flame retardants, form a carbon layer outside the fine water droplets wrapping the nanoparticles, which acts 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 quickly. In addition, the fine water mist fire extinguishing agent does not contain inorganic salts or fluorine, is stable and uniform, is green and environmentally friendly, and is beneficial to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

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

[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 are described in detail below, and the described embodiments are only some embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention. The present invention is further described below in conjunction with specific embodiments.

[0027] In the present invention, the nonionic surfactant, nanoparticles, flavonoids, organic solvent and bio-based thickener are all existing products.

[0028] Nonionic surfactants were purchased from Nagase Co., Ltd.

[0029] Nanoparticle powder was purchased from Shandong DeLan Chemical Co., Ltd.

[0030] Flavonoids were purchased from Gansu Yishengxiang Biotechnology Co., Ltd.

[0031] Organic solvents were purchased from Sinopharm Group.

[0032] The bio-based thickener was purchased from Shanghai MacLean Biotechnology Co., Ltd.

[0033] Example 1

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

[0035] The specific preparation steps are:

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

[0037] (2) dispersing nano-silica powder with a particle size of 45 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.0, ultrasonically treating for 15 min, and continuing to add 0.1% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 4 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 75° C. for 8 hours to obtain modified nano-silica powder;

[0038] (3) Dissolving the nonionic surfactant APG0810 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 20 minutes; adding gum arabic pre-mixed with cold water into the reactor and stirring for 45 minutes;

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

[0040] Example 2

[0041] A non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway comprises the following components in percentage by mass: 15% of non-ionic surfactant APG0810, 0.4% of modified nano silicon dioxide, 1.0% of apigenin, 18% of ethyl acetate, 3.5% of carrageenan, and the balance is deionized water.

[0042] The specific preparation steps are:

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

[0044] (2) dispersing nano-silica powder with a particle size of 50 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 4.0, ultrasonically treating for 20 min, and continuing to add 0.16% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 3.5 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 60° C. for 6 hours to obtain modified nano-silica powder;

[0045] (3) Dissolving the nonionic surfactant APG0810 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 30 minutes; adding the carrageenan pre-mixed with cold water into the reactor and stirring for 25 minutes;

[0046] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir for 55 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0047] Example 3

[0048] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway comprises the following components in percentage by mass: 5% of non-ionic surfactant APG0810, 0.3% of modified nano silicon dioxide, 1.5% of quercetin, 20% of methanol, 4% of gum arabic, and the balance is deionized water.

[0049] The specific preparation steps are:

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

[0051] (2) dispersing nano-silica powder with a particle size of 25 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.5, ultrasonically treating for 30 min, and continuing to add 0.015% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 2 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 80° C. for 5 h to obtain modified nano-silica powder;

[0052] (3) Dissolving the nonionic surfactant APG0810 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 30 minutes; adding gum arabic pre-mixed with cold water into the reactor and stirring for 30 minutes;

[0053] (4) Add the prepared quercetin aqueous solution to the mixed solution in step (3), and stir for 25 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0054] Example 4

[0055] A non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway comprises the following components in percentage by mass: 8% of non-ionic surfactant APG0810, 0.35% of modified nano-silicon dioxide, 0.8% of quercetin, 16% of glacial acetic acid, 2.7% of carrageenan, and the balance is deionized water.

[0056] The specific preparation steps are:

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

[0058] (2) dispersing nano-silica powder with a particle size of 75 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.2, ultrasonically treating for 26 min, and continuing to add 0.028% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 2 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 72° C. for 12 hours to obtain modified nano-silica powder;

[0059] (3) Dissolving the nonionic surfactant APG0810 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 30 minutes; adding the carrageenan pre-mixed with cold water into the reactor and stirring for 50 minutes;

[0060] (4) Add the prepared quercetin aqueous solution to the mixed solution in step (3), and stir for 25 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0061] Example 5

[0062] A nonionic fine water mist fire extinguishing agent for suppressing thermal runaway comprises the following components in percentage by mass: 6% of nonionic surfactant Tween 80, 0.45% of modified nano silicon dioxide, 0.6% of apigenin, 16% of ethanol, 2.8% of gum arabic, and the balance is deionized water.

[0063] The specific preparation steps are:

[0064] (1) adding ethanol and apigenin into a reactor, stirring with a magnetic stirrer for 29 minutes to fully dissolve the apigenin; adding 0.1 M NaOH to adjust the pH value to 7.0, and then filtering with a 0.22 μm microporous filter membrane to obtain an apigenin aqueous solution;

[0065] (2) dispersing nano-silica powder with a particle size of 50 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.5, ultrasonically treating for 25 min, and continuing to add 0.09% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 3 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 60° C. for 10 hours to obtain modified nano-silica powder;

[0066] (3) dissolving the nonionic surfactant Tween 80 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 20 minutes; adding gum arabic pre-mixed with cold water into the reactor and stirring for 35 minutes;

[0067] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir for 40 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0068] Example 6

[0069] A non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway comprises the following components in percentage by mass: 13% of non-ionic surfactant Tween 80, 0.48% of modified nano silicon dioxide, 1.2% of apigenin, 17% of ethyl acetate, 4% of carrageenan, and the balance is deionized water.

[0070] The specific preparation steps are:

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

[0072] (2) dispersing nano-silica powder with a particle size of 65 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.0, ultrasonically treating for 16 min, and continuing to add 0.048% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 2.5 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 68° C. for 9 hours to obtain modified nano-silica powder;

[0073] (3) dissolving the nonionic surfactant Tween 80 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 28 minutes; adding the carrageenan pre-mixed with cold water into the reactor and stirring for 32 minutes;

[0074] (4) Add the prepared apigenin aqueous solution to the mixed solution in step (3), and stir for 46 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0075] Example 7

[0076] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway comprises the following components in percentage by mass: 7% of non-ionic surfactant Tween 80, 0.34% of modified nano silicon dioxide, 1.3% of quercetin, 13% of methanol, 3.6% of gum arabic, and the balance is deionized water.

[0077] The specific preparation steps are:

[0078] (1) adding methanol and quercetin into a reactor, stirring with a magnetic stirrer for 36 minutes to fully dissolve the quercetin; adding 0.1 M NaOH to adjust the pH value to 7.4, and then filtering with a 0.1 μm microporous filter membrane to obtain a quercetin aqueous solution;

[0079] (2) dispersing nano-silica powder with a particle size of 54 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.3, ultrasonically treating for 18 min, and continuing to add 0.017% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 2.6 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 71° C. for 4 hours to obtain modified nano-silica powder;

[0080] (3) dissolving the nonionic surfactant Tween 80 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 22 minutes; adding gum arabic pre-mixed with cold water into the reactor and stirring for 28 minutes;

[0081] (4) Add the prepared quercetin aqueous solution to the mixed solution in step (3), and stir for 46 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0082] Example 8

[0083] A non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway comprises the following components in percentage by mass: 9% of non-ionic surfactant Tween 80, 0.42% of modified nano silicon dioxide, 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:

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

[0086] (2) dispersing nano-silica powder with a particle size of 32 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.8, ultrasonically treating for 18 min, and continuing to add 0.126% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 2.8 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 67° C. for 7 h to obtain modified nano-silica powder;

[0087] (3) dissolving the nonionic surfactant Tween 80 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 19 minutes; adding the carrageenan pre-mixed with cold water into the reactor and stirring for 42 minutes;

[0088] (4) adding the prepared quercetin aqueous solution to the mixed solution in step (3), and stirring for 48 minutes to make the solution uniformly mixed, and the obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0089] Example 9

[0090] A nonionic fine water mist fire extinguishing agent for suppressing thermal runaway comprises the following components in percentage by mass: 11% of nonionic surfactant Tween 20, 0.5% of modified nano silicon dioxide, 0.9% of apigenin, 18% of ethanol, 2.9% of gum arabic, and the balance is deionized water.

[0091] The specific preparation steps are:

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

[0093] (2) dispersing nano-silica powder with a particle size of 40 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.8, ultrasonically treating for 17 min, and continuing to add 0.1% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 3.5 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 67° C. for 11 hours to obtain modified nano-silica powder;

[0094] (3) dissolving the nonionic surfactant Tween 20 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 24 minutes; adding gum arabic premixed with cold water into the reactor and stirring for 47 minutes;

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

[0096] Example 10

[0097] A nonionic fine water mist fire extinguishing agent for inhibiting thermal runaway comprises the following components in percentage by mass: 14% of nonionic surfactant Tween 20, 0.48% of modified nano silicon dioxide, 1.1% of apigenin, 17% of ethyl acetate, 3.4% of carrageenan, and the balance is deionized water.

[0098] The specific preparation steps are:

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

[0100] (2) dispersing nano-silica powder with a particle size of 38 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.2, ultrasonically treating for 21 min, and continuing to add 0.096% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 2.4 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 78° C. for 5 h to obtain modified nano-silica powder;

[0101] (3) dissolving the nonionic surfactant Tween 20 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 16 minutes; adding the carrageenan pre-mixed with cold water into the reactor and stirring for 37 minutes;

[0102] (4) Add the prepared apigenin aqueous solution to the solution mixed in step (3), and stir for 43 minutes to make the solution uniformly mixed. The obtained aqueous solution is a non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway.

[0103] Embodiment 11

[0104] A nonionic fine water mist fire extinguishing agent for suppressing thermal runaway comprises the following components in percentage by mass: 6% of nonionic surfactant Tween 20, 0.33% of modified nano silicon dioxide, 1.4% of quercetin, 16% of methanol, 3.4% of gum arabic, and the balance is deionized water.

[0105] The specific preparation steps are:

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

[0107] (2) dispersing nano-silica powder with a particle size of 27 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.6, ultrasonically treating for 21 min, and continuously adding 0.033% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 3.9 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 74° C. for 6.5 hours to obtain modified nano-silica powder;

[0108] (3) dissolving the nonionic surfactant Tween 20 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 17 minutes; adding gum arabic premixed with cold water into the reactor and stirring for 34 minutes;

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

[0110] Example 12

[0111] A nonionic fine water mist fire extinguishing agent for inhibiting thermal runaway comprises the following components in percentage by mass: 12% of nonionic surfactant Tween 20, 0.35% of modified nano silicon dioxide, 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:

[0113] (1) adding glacial acetic acid and quercetin into a reactor, stirring with a magnetic stirrer for 36 minutes to fully dissolve the quercetin; adding 0.1 M NaOH to adjust the pH value to 7.5, and then filtering with a 0.1 μm microporous filter membrane to obtain a quercetin aqueous solution;

[0114] (2) dispersing nano-silica powder with a particle size of 46 nm in anhydrous ethanol, adding 0.1 M dilute hydrochloric acid to adjust the pH to 3.7, ultrasonically treating for 26 min, and continuing to add 0.028% by weight of silane coupling agent γ-aminopropyltriethoxysilane, stirring for 3.5 hours to allow γ-aminopropyltriethoxysilane to fully react with nano-silica; after the reaction is completed, filtering, washing, and drying in an oven at 64° C. for 8.5 hours to obtain modified nano-silica powder;

[0115] (3) dissolving the nonionic surfactant Tween 20 in a reactor containing deionized water, adding the modified nano-silica powder, and transferring the reactor to an ultrasonic processor for ultrasonic treatment for 24 minutes; adding the carrageenan pre-mixed with cold water into the reactor and stirring for 54 minutes;

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

[0117] Comparative Example 1

[0118] A water mist fire extinguishing agent for inhibiting thermal runaway, except that the non-ionic surfactant component is not included, the remaining steps are the same as those of Example 1.

[0119] Comparative Example 2

[0120] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, except that the modified nanoparticles are not included, and the remaining steps are the same as those of Example 1.

[0121] Comparative Example 3

[0122] A non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway, except that the agent does not contain flavonoid compounds, and the remaining steps are the same as those of Example 1.

[0123] Comparative Example 4

[0124] A non-ionic fine water mist fire extinguishing agent for suppressing thermal runaway, except that it does not contain a bio-based thickener, and the remaining steps are the same as those of Example 1.

[0125] Comparative Example 5

[0126] A pure water mist fire extinguishing agent for suppressing thermal runaway fires.

[0127] Comparative Example 6

[0128] Blank experiment, no fire extinguishing agent is used.

[0129] The non-ionic fine water mist thermal runaway suppression fire extinguishing agent prepared in Examples 1-12 and the thermal runaway suppression fire extinguishing agent prepared in Comparative Examples 1-6 were selected for testing.

[0130] During the implementation of the present invention, at room temperature, the lithium battery is seamlessly fitted with a heating rod of the same size to ensure that the battery can be heated evenly. The 18650 type ternary lithium electronic battery INR18650-26E is selected, with a nominal capacity of 2.6Ah and a nominal voltage of 3.65V. In order to compare the inhibitory effect of fine water mist under different modes on lithium battery fires, each group of battery samples is filled with a constant current of 1A so that 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 120W is selected to induce heating of the lithium battery. Once thermal runaway begins, the heating mode is immediately turned off. The fine water mist nozzle is set 20cm above the lithium battery, and the pressure of the nozzle is set to 1.5MPa and the spray angle is set to 90°.

[0131] The nonionic fine water mist fire extinguishing agent for suppressing thermal runaway prepared in Examples 1-12 and the fire extinguishing agent for suppressing thermal runaway prepared in Comparative Examples 1-6 were loaded into the fine water mist system, and a 120W heating rod was used to slowly heat the lithium electronic battery. When the lithium battery had thermal runaway and produced jet flames, the fine water mist system was turned on and continued to spray until the temperature of the lithium battery dropped below 50°C. The recorded experimental data are shown in Table 1.

[0132] Table 1 Performance test results of water mist fire extinguishing agents prepared in Examples 1 to 12 and Comparative Examples 1 to 5

[0133]

[0134] The initial temperature of thermal runaway reflects the temperature threshold at which the fine water mist fire extinguishing agent begins to take effect in a fire environment, and reflects the sensitivity of the fine water mist fire extinguishing agent. The determination of the maximum temperature characterizes the most serious degree of thermal runaway of the lithium-ion battery. The lower the maximum temperature, the stronger the ability of the fine water mist fire extinguishing agent to suppress heat during the fire extinguishing process. The maximum cooling rate is a key indicator to measure the cooling effect of the fine water mist fire extinguishing agent. A higher cooling rate means that the fine water mist can quickly absorb heat, causing the temperature in the fire area to drop rapidly, thereby effectively suppressing the spread of the fire. It is generally believed that when the temperature of the lithium battery drops below 50°C, the thermal runaway behavior can be effectively controlled. Therefore, the present invention uses the time required to drop to 50°C as a standard to measure the performance of the fire extinguishing agent. The shorter the time required to drop to 50°C, the faster the fire extinguishing agent extinguishes the fire.

[0135] As shown in Table 1, compared with Comparative Example 6 without any fire extinguishing operation, the initial temperature of thermal runaway of Examples 1 to 12 can be controlled below 190°C, indicating that the non-ionic fine water mist fire extinguishing agent for inhibiting thermal runaway provided by the present invention can effectively prevent thermal runaway; the maximum temperatures of Examples 1 to 12 are all below 630°C, which is lower than 773.8°C of Comparative Example 6, among which Example 1 can reduce the maximum temperature to 325.8°C, and the maximum temperature is significantly reduced, indicating that it can effectively control the development of the fire; the maximum cooling rate of Examples 1 to 12 can reach a maximum of 15.6°C / s, and the minimum is 2.45°C / s, both of which are higher than the comparative examples; the time required for Examples 1 to 12 to drop to 50°C is only 405s at the longest and 136s at the shortest, which is significantly faster than the comparative examples.

[0136] All indicators of Example 1 are better than those of Comparative Example 1 which does not contain a non-ionic surfactant. This is because the non-ionic surfactant has a good wetting effect and can significantly reduce the surface tension of water, making it easier for the fine water mist to disperse into smaller droplets, which can better wet the surface of the burning object, absorb heat faster and cool the burning area.

[0137] All indicators of Example 1 are better than those of Comparative Example 2 which does not contain modified nanoparticles, because the modified nano-silicon dioxide has better dispersibility, so that it can be evenly dispersed in the fine water mist droplets, making the fine water mist evenly wrapping the modified nanoparticles not easily vaporized and easier to pass through the flame to reach the combustion center.

[0138] All indicators of Example 1 are better than those of Comparative Example 3 which does not contain flavonoids, because flavonoids, as a natural flame retardant, have strong antioxidant properties and can remove free radicals generated during combustion, thereby interrupting the chain reaction and reducing the spread of flames. By inhibiting free radicals, flavonoids can help reduce the secondary oxidation of materials after combustion and reduce the possibility of re-ignition.

[0139] All indicators of Example 1 are better than those of Comparative Example 4 which does not contain a bio-based thickener, because the bio-based thickener is a natural polysaccharide, which can significantly improve the viscosity of the solution, reduce the evaporation rate of water, and form a more stable and lasting water mist.

[0140] In summary, the non-ionic thermal runaway suppression fire extinguishing agents of Examples 1 to 12 provided by the present invention have short fire extinguishing time, fast fire extinguishing speed, high fire extinguishing efficiency, are not likely to cause secondary damage during the fire extinguishing process, and are green and environmentally friendly.

[0141] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A non-ionic water mist fire extinguishing agent for suppressing thermal runaway, characterized in that: The invention comprises the following components in percentage by mass: 5.0-15% of nonionic surfactant, 0.3-0.5% of modified nanoparticles, 2.5-4.0% of bio-based thickener, 0.5-1.5% of flavonoid compound, 15%-20% of organic solvent and the balance of deionized water.

2. A non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 1, characterized in that: The nonionic surfactant is selected from any one of polycarbon alkyl glycoside 0810, polyoxyethylene sorbitan monooleate and polyoxyethylene sorbitan monolaurate.

3. A non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 1, characterized in that: The modified nanoparticles are modified nano-silicon dioxide; and the bio-based thickener is carrageenan or gum arabic.

4. A non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 1, characterized in that: The flavonoid compound is quercetin or apigenin; the organic solvent is any one of methanol, ethanol, ethyl acetate and glacial acetic acid.

5. A method for preparing a non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to any one of claims 1 to 4, characterized in that: The following steps are involved: 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; The nonionic surfactant is dissolved in a reactor containing deionized water; the modified nanoparticles are then added, and the reactor is transferred to an ultrasonic processor for ultrasonic treatment; the bio-based thickener pre-mixed with cold water is added to the reactor and stirred to obtain a solution B; The prepared solution A is added to the obtained solution B, and stirred for 25 to 55 minutes to fully mix the solution A and the solution B to obtain an aqueous solution, which is a non-ionic fine water mist thermal runaway suppression fire extinguishing agent.

6. The method for preparing a non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 5, characterized in that: The filtration is carried out using a microporous membrane, wherein the pore size of the microporous membrane is 0.1 μm, 0.22 μm or 0.45 μm; and the alkaline solution is 0.1 M NaOH.

7. The method for preparing a non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 5, characterized in that: The ultrasonic time is 15 to 30 minutes.

8. The method for preparing a non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 5, characterized in that: The method for preparing the modified nanoparticles comprises the following steps: Nano-silicon dioxide powder is dispersed in anhydrous ethanol, acid is added thereto to adjust the pH to 3.0-4.0, ultrasonic treatment is performed for 10-30 minutes, and silane coupling agent is continuously added, and stirring is performed for 2-4 hours to allow the silane coupling agent and nano-silicon dioxide to fully react; after the reaction is completed, filtering, washing and drying are performed to obtain modified nano-particles.

9. The method for preparing a non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to claim 8, characterized in that: The acid is 0.1M 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-silicon dioxide is 25-75nm.

10. The use of the non-ionic water mist fire extinguishing agent for suppressing thermal runaway according to any one of claims 1 to 4, characterized in that: Used to suppress thermal runaway of lithium-ion batteries.

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