Vermiculite lithium battery fire extinguishing agent based on synchronous modification process, preparation method and application

Abstract

The invention relates to the technical field of lithium battery fire prevention and extinguishment, in particular to a vermiculite lithium battery fire extinguishing agent based on a synchronous modification technology, a preparation method and application. According to the method, after vermiculite raw powder, a metal inorganic salt aqueous solution and hydrogen peroxide are mixed and heated at the same time, modified vermiculite is obtained, then the modified vermiculite, a dispersing agent, a thickening agent and water are mixed, and the vermiculite lithium battery fire extinguishing agent based on the synchronous modification technology is obtained. The vermiculite lithium battery fire extinguishing agent is obtained; through a synchronous modification process, metal inorganic salt and hydrogen peroxide are adopted to modify vermiculite raw powder at the same time, so that the hydrogen peroxide and the metal inorganic salt generate a synergistic effect between vermiculite layers, a hydrogen peroxide-metal inorganic salt-vermiculite ternary reaction environment is formed, and synchronous expansion and nano modification between the vermiculite layers are realized; and the fire extinguishing agent is endowed with extremely high thermal stability and mechanical strength, so that the formed uniform nano-distributed active components show an efficient and lasting chemical fire extinguishing function, and the problem that the fire extinguishing performance is poor due to the fact that the active components in the vermiculite lithium battery fire extinguishing agent are not uniformly distributed and are easy to fall off is solved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery fire prevention and extinguishing technology, specifically to a vermiculite lithium battery fire extinguishing agent based on a synchronous modification process, its preparation method and application, and in particular to a fire extinguishing agent, its preparation method and application for extinguishing lithium battery fires. Background Technology

[0002] With the profound transformation of the global energy structure and the widespread application of clean energy, lithium batteries, with their significant advantages such as high energy density, long cycle life, and low self-discharge rate, have been widely used in many fields such as electric vehicles, energy storage power stations, and portable electronic devices, becoming a key force in promoting green energy development. However, while lithium batteries bring great convenience and economic benefits, their thermal runaway fire problem has become a major factor hindering their further large-scale promotion and application.

[0003] Lithium-ion battery thermal runaway is an extremely complex and dangerous process. When a cell within a lithium-ion battery experiences thermal runaway due to overcharging, over-discharging, short circuits, or mechanical damage, the cell's temperature can rapidly rise to several hundred degrees Celsius within a very short time. This high-temperature environment causes violent reactions in the cell's internal chemicals, resulting in the ejection of large amounts of high-temperature flammable gases and particulate matter. These ejected materials possess extremely high energy; upon contact with adjacent cells, they rapidly heat them, causing those cells to also enter a state of thermal runaway, creating a chain reaction that leads to the rapid spread of fire within the battery pack. Furthermore, the combustion of lithium-ion batteries produces large amounts of highly toxic and corrosive gases, such as hydrogen fluoride and hydrogen chloride. These gases not only pose serious health risks but also cause significant environmental damage. In addition, lithium-ion battery fires are characterized by rapid spread and a high risk of reignition. Traditional fire extinguishing agents often have limited effectiveness in controlling such fires and preventing reignition, posing a significant challenge to the safe use of lithium-ion batteries.

[0004] Expanded vermiculite is a natural layered silicate mineral. When heated to high temperatures, the moisture between its layers evaporates, causing the interlayer structure to expand and form a porous material with numerous pores. These pores not only effectively prevent heat transfer and lower the temperature at the fire scene, but also adsorb gases and particulate matter generated during combustion, playing a role in inhibiting the spread of fire. Simultaneously, expanded vermiculite possesses good chemical and thermal stability, maintaining structural integrity even at high temperatures, providing reliable performance assurance for fire extinguishing agents, and is considered an ideal substrate for preparing lithium battery fire extinguishing agents. Inorganic salts possess certain hydration capabilities, intercalation, expansion, and the ability to chemically inhibit flame free radicals. Hydration allows inorganic salts to absorb moisture from the surrounding environment; during a fire, the evaporation of this moisture absorbs a significant amount of heat, thus lowering the temperature. Intercalation and expansion properties allow inorganic salts to enter the interlayer structure of vermiculite, altering its physical and chemical properties and enhancing its heat insulation and adsorption performance. The function of chemically inhibiting flame free radicals can interrupt the combustion chain reaction, effectively suppressing the spread of flames. Therefore, combining vermiculite with inorganic salts can fully leverage the synergistic effect of physical and chemical fire extinguishing mechanisms, becoming an important approach in lithium battery fire extinguishing agent research. For example, Chinese invention publication CN117797439A discloses a battery fire extinguishing material based on vermiculite modification and its preparation method. By modifying vermiculite with a compound inorganic salt solution, its performance is improved, enhancing its effectiveness as a fire extinguishing agent. However... Both Chinese invention patents, publication number CN119113469A and authorization announcement number CN114602111B, describe the preparation process of lithium battery fire extinguishing agents by first expanding and drying vermiculite with hydrogen peroxide (H2O2), and then blending it with soluble salts or inorganic powders as additives. The introduction of hydrogen peroxide can increase the expansion ratio of vermiculite, making the product structure more uniform and providing new ideas and methods for improving the performance of fire extinguishing agents. However, during the expansion and drying process, the interlayer structure, chemical environment, and charge properties of vermiculite undergo fundamental changes. This change means that subsequently added inorganic salts can only be adsorbed on the surface and macroscopic pores of the expanded vermiculite, making it difficult for them to enter the interlayer nanodomains of vermiculite. Due to the uneven distribution of inorganic salts in vermiculite, on the one hand, pore blockage may occur. When inorganic salt particles accumulate in the pores of vermiculite, they hinder the flow of gas and particulate matter, affecting the adsorption performance of vermiculite and reducing its ability to absorb combustion products and heat, thus weakening the extinguishing effect of the fire extinguishing agent. On the other hand, the issue of component detachment cannot be ignored. Due to the weak bonding between inorganic salts and expanded vermiculite, during the use of the fire extinguishing agent, external environmental factors (such as temperature, humidity, and mechanical vibration) can cause inorganic salts to detach from the vermiculite surface, leading to changes in the composition of the fire extinguishing agent and affecting its long-term stability.Moreover, the detached inorganic salts may form new hazards at the fire scene, further aggravating the fire's damage and preventing the extinguishing agent from fully utilizing the chemical inhibition of flame free radicals and other functions of the inorganic salts during the extinguishing process, thus reducing the extinguishing effectiveness of the extinguishing agent.

[0005] In summary, existing lithium battery fire extinguishing agent preparation technologies suffer from problems such as uneven distribution of inorganic salts, easy clogging of pores, and component loss in the composite of inorganic salts and expanded vermiculite. These problems seriously affect the fire extinguishing efficiency, long-term stability, and production feasibility of the fire extinguishing agent. Summary of the Invention

[0006] To address the problem of poor fire extinguishing performance caused by uneven distribution and easy detachment of active ingredients in existing vermiculite lithium battery fire extinguishing agents, this invention provides a vermiculite lithium battery fire extinguishing agent based on a synchronous modification process, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a method for preparing a vermiculite lithium battery fire extinguishing agent based on a simultaneous modification process, comprising: Vermiculite powder, aqueous solution of metal inorganic salt, and hydrogen peroxide are mixed simultaneously to obtain a mixed reaction system; wherein, in the mixed reaction system, the mass concentration of hydrogen peroxide is 15%-35%, the mass ratio of vermiculite powder to metal inorganic salt is (1:0.5)-(1:3), and the mass ratio of vermiculite powder to hydrogen peroxide is (1:1)-(1:6). The mixed reaction system was heated to obtain modified vermiculite; Modified vermiculite, dispersant, thickener and water are mixed to obtain vermiculite lithium battery fire extinguishing agent; wherein, by mass percentage, the amount of modified vermiculite is 15%-40%, the amount of dispersant is 0.5%-1.5%, the amount of thickener is 0.2%-0.8%, and the balance is water.

[0008] Optionally, the inorganic metal salt is one or more of magnesium salt, sodium salt, potassium salt, aluminum salt, and iron salt.

[0009] Optionally, the heating method for heating the mixed reaction system is oil bath heating or microwave heating.

[0010] Optionally, when the heating method for heating the mixed reaction system is microwave heating, the power of microwave heating is 600-900W and the heating time is 1-6min; when the heating method for heating the mixed reaction system is oil bath heating, the heating temperature of oil bath heating is 80-100℃ and the heating time is 4-10min.

[0011] Optionally, the dispersant is sodium polycarboxylate and / or sodium polyacrylate; the thickener is carboxymethyl cellulose and / or hydroxyethyl cellulose.

[0012] Optionally, the vermiculite lithium battery fire extinguishing agent further includes a wetting agent, a defoamer, a preservative, and a pH adjuster, wherein, by mass percentage, the amount of the wetting agent is 0.05%-0.2%, the amount of the defoamer is 0.1%-0.5%, the amount of the preservative is 0.05%-0.2%, and the pH value of the vermiculite lithium battery fire extinguishing agent is 7.5-8.5.

[0013] Optionally, the wetting agent is an organosilicone surfactant; the defoamer is an organosilicone defoamer emulsion; the preservative is an isothiazolinone compound; and the pH adjuster is ammonia.

[0014] Optionally, the method for preparing the vermiculite lithium battery fire extinguishing agent by mixing modified vermiculite, dispersant, thickener and water is as follows: Add preservative, wetting agent, dispersant and half the amount of defoamer to water in sequence, and stir at low speed at 200-400 rpm until homogeneous to obtain the first mixture system; Add a pH adjuster to the first mixture to precisely adjust the pH of the system to a slightly alkaline environment of 7.5-8.5, thus obtaining the second mixture. Slowly add the thickener to the second mixture and immediately increase the rotation speed to 1500-3500 rpm for high-speed shear dispersion for 10-30 minutes until a uniform, transparent, particle-free colloidal solution is formed, thus obtaining the third mixture. At a stirring speed of 400-800 rpm, slowly add modified vermiculite to the third mixing system. After the modified vermiculite is added, adjust the stirring speed to 800-1500 rpm and disperse for 10-20 minutes to ensure that the vermiculite particles are fully wetted and dispersed, thus obtaining the fourth mixing system. At a stirring speed of 200-400 rpm, the remaining defoamer was added to the fourth mixing system, and defoaming was carried out for 5-10 minutes. The pH value and viscosity were measured, and the viscosity was finely adjusted to the target viscosity with water to obtain the vermiculite lithium battery fire extinguishing agent.

[0015] A vermiculite lithium battery fire extinguishing agent based on a synchronous modification process is prepared using the above-mentioned preparation method.

[0016] The above-mentioned vermiculite lithium battery fire extinguishing agent based on synchronous modification process is used in lithium battery fire prevention and extinguishing.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for preparing a vermiculite lithium battery fire extinguishing agent based on a simultaneous modification process. The method involves first simultaneously mixing and heating raw vermiculite powder, an aqueous solution of a metal inorganic salt, and hydrogen peroxide to obtain modified vermiculite. Then, the modified vermiculite, a dispersant, a thickener, and water are mixed to obtain the vermiculite lithium battery fire extinguishing agent. This method utilizes a simultaneous modification process, where the raw vermiculite powder is modified by both the metal inorganic salt and hydrogen peroxide. This allows the hydrogen peroxide and the metal inorganic salt to synergistically interact within the vermiculite layers, forming a ternary reaction environment of "hydrogen peroxide (H2O2) - metal inorganic salt - vermiculite". Metal ions in the organic salt pre-alter the chemical environment between vermiculite powder layers, enhancing the electrostatic anchoring effect on hydrogen peroxide. This allows the gas generated by hydrogen peroxide decomposition to act more effectively and uniformly on the vermiculite layer, resulting in more complete expansion and higher expansion efficiency. Simultaneously, metal ions form "ion bridges" between layers, guiding the gas generated by hydrogen peroxide decomposition to diffuse uniformly along the interlayer nanochannels. This allows the inorganic metal salt to be inserted into the interlayer domain simultaneously during the expansion process, increasing the intercalation rate. This nanoscale uniform distribution effectively avoids the pore blockage problem caused by the enrichment of inorganic salts on the surface in traditional processes. During high-temperature fire extinguishing, the metal oxides generated from the decomposition of inorganic metal salts form a nanoscale "scaffold structure" between vermiculite layers. Metal oxide particles fill these layers, forming a three-dimensional network through chemical bonding, which enhances the compressive strength of the expanded vermiculite particles. Simultaneously, the high melting point and low thermal conductivity of the metal oxides create a thermal resistance barrier between the layers, improving the thermal stability of the extinguishing agent. This allows it to form a more stable insulating layer when covering battery modules, effectively resisting the impact of high-temperature ejected materials and ensuring the efficient and long-lasting chemical fire extinguishing function. By compounding modified vermiculite, dispersants, thickeners, and water, a stable colloidal system can be constructed, further preventing particle aggregation. This simple method significantly reduces production energy consumption and costs. Through simultaneous modification processes, the metal oxide scaffold effect, and a weakly alkaline colloidal system, the performance of lithium battery fire extinguishing agents is comprehensively improved, providing an efficient, reliable, and low-cost solution for lithium battery safety, with significant economic and social value.

[0018] Secondly, the preparation method of the present invention uses a specific polycarboxylate dispersant and a cellulose ether thickener, and first constructs a stable colloid under weakly alkaline conditions, and then disperses the main raw materials, which ensures that the synchronously modified vermiculite particles can be suspended stably in the system for a long time, preventing sedimentation and agglomeration, and further improving the storage stability and reliability of the product.

[0019] A vermiculite-based lithium battery fire extinguishing agent, prepared using the aforementioned method, is described above. This fire extinguishing agent achieves comprehensive breakthroughs in fire extinguishing efficiency, storage stability, process reliability, and environmental friendliness through the construction of a "ternary synergistic reaction environment," the enhancement of the metal oxide "scaffolding effect," the stabilization of the weakly alkaline colloidal system, and the optimization of the one-step process. It provides an efficient, reliable, and low-cost solution for lithium battery safety, possessing significant economic and social value.

[0020] The above-mentioned vermiculite lithium battery fire extinguishing agent based on synchronous modification process is applied in lithium battery fire prevention and extinguishing. When applied, this fire extinguishing agent can form a stable heat insulation layer between lithium batteries. This layer not only isolates the battery's combustibles from oxygen, thus suffocating them and effectively inhibiting the chain reaction of battery combustion, but also prevents reignition caused by residual internal heat or external heat sources, ensuring the long-lasting fire extinguishing effect. It not only exhibits excellent fire extinguishing performance (rapid fire extinguishing, prevention of reignition, and stable covering layer), but also demonstrates good storage stability, improving lithium battery safety and promoting the development and application of lithium batteries. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a method for preparing vermiculite lithium battery fire extinguishing agent based on a synchronous modification process according to the present invention.

[0022] Figure 2 A structural diagram of the fire extinguishing agent size fire extinguishing performance testing device prepared for an embodiment of the present invention.

[0023] Among them, 1-sealed combustion chamber, 2-pressure source, 3-solenoid valve, 4-extinguishing agent nozzle, 5-safety pressure relief valve, 6-camera, 7-data acquisition line, 8-battery mounting bracket. Detailed Implementation

[0024] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0026] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0027] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0028] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0031] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0032] See Figure 1 This invention provides a method for preparing a vermiculite lithium battery fire extinguishing agent based on a synchronous modification process, comprising: S1: Vermiculite powder, aqueous solution of metal inorganic salt, and hydrogen peroxide are mixed simultaneously to obtain a mixed reaction system; wherein, in the mixed reaction system, the mass concentration of hydrogen peroxide is 15%-35%, the mass ratio of vermiculite powder to metal inorganic salt is (1:0.5)-(1:3), and the mass ratio of vermiculite powder to hydrogen peroxide is (1:1)-(1:6); preferably, the metal inorganic salt is one or more of magnesium salt, sodium salt, potassium salt, aluminum salt, and iron salt, such as magnesium sulfate (MgSO4), sodium chloride (NaCl), aluminum sulfate (Al2(SO4)3), ferric sulfate (Fe2(SO4)3), etc.

[0033] S2: The mixed reaction system is heated to obtain modified vermiculite; preferably, the heating method for heating the mixed reaction system is oil bath heating or microwave heating; more preferably, the heating method for heating the mixed reaction system is microwave heating, the microwave heating power is 600-900W, and the heating time is 1-6min; the heating method for heating the mixed reaction system is oil bath heating, the oil bath heating temperature is 80-100℃, and the heating time is 4-10min.

[0034] S3: Mix modified vermiculite, dispersant, thickener, and water to obtain vermiculite lithium battery fire extinguishing agent; wherein, by mass percentage, the amount of modified vermiculite is 15%-40%, the amount of dispersant is 0.5%-1.5%, the amount of thickener is 0.2%-0.8%, and the remainder is water. Preferably, the vermiculite lithium battery fire extinguishing agent further includes a wetting agent, an antifoaming agent, a preservative, and a pH adjuster, wherein, by mass percentage, the amount of wetting agent is 0.05%-0.2%, the amount of antifoaming agent is 0.1%-0.5%, the amount of preservative is 0.05%-0.2%, and the pH value of the vermiculite lithium battery fire extinguishing agent is 7.5-8.5. More preferably, the dispersant is sodium polycarboxylate (such as Dispex N40, Orotan 1124, Tamol NN 8901) and / or sodium polyacrylate; the thickener is carboxymethyl cellulose and / or hydroxyethyl cellulose; the wetting agent is a silicone surfactant, such as TEGO Wet 270; the defoamer is a silicone defoamer emulsion, such as BYK-024 and BYK-028; the preservative is an isothiazolinone compound, such as Kathon or Preventol DZ; and the pH adjuster is ammonia. The specific method is as follows: Add preservative, wetting agent, dispersant and half the amount of defoamer to deionized water in sequence, and stir at low speed at 200-400 rpm until homogeneous to obtain the first mixed system; A pH adjuster was added to the first mixing system to precisely adjust the pH of the system to a weakly alkaline environment of 7.5-8.5, so that the anionic dispersant could exert its best effect, thus obtaining the second mixing system. Slowly add the thickener to the second mixture and immediately increase the rotation speed to 1500-3500 rpm for high-speed shear dispersion for 10-30 minutes until a uniform, transparent, particle-free colloidal solution is formed, thus obtaining the third mixture. At a medium stirring speed of 400-800 rpm, slowly add modified vermiculite to the third mixing system. After the modified vermiculite is added, adjust the stirring speed to 800-1500 rpm and disperse for 10-20 minutes to ensure that the vermiculite particles are fully wetted and dispersed to obtain the fourth mixing system. Add the remaining defoamer to the fourth mixing system at a low stirring speed of 200-400 rpm, defoam for 5-10 minutes, check the pH value and viscosity, and if necessary, add deionized water to make up to 100% and fine-tune the viscosity to obtain vermiculite lithium battery fire extinguishing agent.

[0035] This preparation method employs a simultaneous process to create a ternary reaction environment of "hydrogen peroxide (H2O2) - metallic inorganic salt - vermiculite," achieving simultaneous expansion and nano-modification of the vermiculite interlayers. This results in a stable composite structure in which inorganic salt decomposition products (such as MgO and Al2O3) are embedded within the vermiculite interlayers. This composite structure endows the fire extinguishing agent with extremely high thermal stability and mechanical strength, enabling the formed insulation layer to effectively resist the impact of the battery jet gas flow. The nano-distributed active ingredients provide efficient and long-lasting chemical fire extinguishing capabilities. Simultaneously, a specific polycarboxylate dispersant and cellulose ether thickener are compounded, and a stable colloid is first constructed under weakly alkaline conditions before dispersing the main raw materials. This process ensures that the simultaneously modified vermiculite particles can remain stably suspended in the system for a long period, preventing sedimentation and agglomeration, and greatly improving the product's storage stability and reliability. This method achieves vermiculite modification in a one-step process, simplifying the production process, reducing energy consumption and costs, and demonstrating greater potential for commercialization and large-scale application.

[0036] To further illustrate the technical solution and beneficial effects of the present invention, four specific embodiments are provided below: General Procedure: Mix an aqueous solution of inorganic salts of specified mass and concentration with hydrogen peroxide (H2O2) in an open or corrosion-resistant container with a pressure relief cap. Slowly add raw vermiculite powder (particle size 20-100 mesh) while stirring to form a homogeneous slurry. Then, proceed with the reaction using the specified heating method. After the reaction, dry the resulting expanded vermiculite product at 105°C to constant weight, cool, and weigh. Calculate the expansion ratio (mass of expanded product / mass of raw powder).

[0037] The formulations and process parameters for Examples 1-4 are shown in the table below:

[0038] The modified vermiculite prepared in the above examples was then processed according to the fire extinguishing agent formulation. The specific steps are as follows: Premixed base solution: Add 60% of the total amount of deionized water to the preparation vessel, and add 0.1% isothiazolinone preservative, 0.1% TEGO Wet 270 wetting agent, 1.0% sodium polycarboxylate dispersant (DispexN40) and 0.1% BYK-024 defoamer (half of the total amount) in sequence while stirring at a low speed of 300 rpm. Stir for 10 min until uniform to obtain the first mixed system.

[0039] Adjusting the pH value: Slowly add ammonia water to the first mixture to adjust the pH value of the first mixture to 8.0, thus obtaining the second mixture.

[0040] Thickening: Slowly sprinkle 0.5% hydroxyethyl cellulose (Walocel HEC) powder into the second mixture, increase the stirring speed to 2500 rpm, and disperse at high speed for 20 minutes to form a uniform and transparent colloid, thus obtaining the third mixture.

[0041] Dispersing the main material: Reduce the rotation speed to 600 rpm and slowly add 30% of the modified vermiculite to the third mixing system in batches. After all the vermiculite has been added, increase the rotation speed to 1200 rpm and continue dispersing for 15 minutes to obtain the fourth mixing system.

[0042] Defoaming and volume adjustment: Adjust the rotation speed to 300 rpm, add the remaining 0.1% BYK-024 defoamer to the fourth mixing system, defoam slowly for 8 minutes, and finally add deionized water to make up to 100%, and adjust the viscosity to a suitable range to obtain the vermiculite lithium battery fire extinguishing agent prepared in each embodiment.

[0043] The fire extinguishing performance of the vermiculite lithium battery fire extinguishing agents prepared in Examples 1-4 was tested, see [reference needed]. Figure 2 The testing apparatus includes a sealed combustion chamber 1, a pressure source 2, a solenoid valve 3, a fire extinguishing agent nozzle 4, a safety relief valve 5, a camera 6, a data acquisition cable 7, and a battery holder 8. The sealed combustion chamber 1 provides the testing environment. The battery holder 8 is fixed to the bottom of the sealed combustion chamber 1 for battery installation. The camera 6 is installed inside the sealed combustion chamber 1 to collect relevant image data. The pressure source 2 is connected to the sealed combustion chamber 1 to regulate its pressure. The fire extinguishing agent nozzle 4 is connected to a fire extinguishing container containing the fire extinguishing agent to be tested. The fire extinguishing agent nozzle 4 is connected to the solenoid valve 3 and the safety relief valve 5. The data acquisition cable is connected to the camera 6 to acquire image data and transmit it to a control terminal for data analysis.

[0044] Test method: A 38Ah lithium iron phosphate battery (SOC=100%) was placed in a sealed combustion chamber 1 and thermal runaway was induced by external heating. Three seconds after the appearance of open flame, 200g of extinguishing agent was automatically sprayed from extinguishing agent nozzle 4. The extinguishing time was recorded, and the presence of reignition and the integrity of the covering layer were observed within 10 minutes. The test results are shown in the table below:

[0045] The results of Examples 1-4 demonstrate that, within the parameter range described in this invention, high-performance fire extinguishing agents can be successfully prepared through a simultaneous modification process of hydrogen peroxide (H2O2)-inorganic salt-vermiculite combined with an optimized additive system. The resulting products not only exhibit excellent fire extinguishing performance (rapid extinguishing, prevention of reignition, and stability of the covering layer) but also demonstrate good storage stability, proving the reliability of the process and the superiority of the formulation system of this invention.

[0046] A vermiculite-based lithium battery fire extinguishing agent, prepared using the aforementioned method, is described above. This fire extinguishing agent achieves comprehensive breakthroughs in fire extinguishing efficiency, storage stability, process reliability, and environmental friendliness through the construction of a "ternary synergistic reaction environment," the enhancement of the metal oxide "scaffolding effect," the stabilization of the weakly alkaline colloidal system, and the optimization of the one-step process. It provides an efficient, reliable, and low-cost solution for lithium battery safety, possessing significant economic and social value.

[0047] The above-mentioned vermiculite lithium battery fire extinguishing agent based on synchronous modification process is applied in lithium battery fire prevention and extinguishing. When applied, this fire extinguishing agent can form a stable heat insulation layer between lithium batteries. This layer not only isolates the battery's combustibles from oxygen, thus suffocating them and effectively inhibiting the chain reaction of battery combustion, but also prevents reignition caused by residual internal heat or external heat sources, ensuring the long-lasting fire extinguishing effect. It not only exhibits excellent fire extinguishing performance (rapid fire extinguishing, prevention of reignition, and stable covering layer), but also demonstrates good storage stability, improving lithium battery safety and promoting the development and application of lithium batteries.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A method for preparing vermiculite lithium battery fire extinguishing agent based on a simultaneous modification process, characterized in that, include: Vermiculite powder, aqueous solution of metal inorganic salt, and hydrogen peroxide are mixed simultaneously to obtain a mixed reaction system; wherein, in the mixed reaction system, the mass concentration of hydrogen peroxide is 15%-35%, the mass ratio of vermiculite powder to metal inorganic salt is (1:0.5)-(1:3), and the mass ratio of vermiculite powder to hydrogen peroxide is (1:1)-(1:6). The mixed reaction system was heated to obtain modified vermiculite; Modified vermiculite, dispersant, thickener and water are mixed to obtain vermiculite lithium battery fire extinguishing agent; wherein, by mass percentage, the amount of modified vermiculite is 15%-40%, the amount of dispersant is 0.5%-1.5%, the amount of thickener is 0.2%-0.8%, and the balance is water.

2. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 1, characterized in that, The inorganic metal salt is one or more of magnesium salt, sodium salt, potassium salt, aluminum salt, and iron salt.

3. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 1, characterized in that, The heating method for heating the mixed reaction system is oil bath heating or microwave heating.

4. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 3, characterized in that, When the heating method for heating the mixed reaction system is microwave heating, the microwave heating power is 600-900W and the heating time is 1-6min; when the heating method for heating the mixed reaction system is oil bath heating, the oil bath heating temperature is 80-100℃ and the heating time is 4-10min.

5. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 1, characterized in that, The dispersant is sodium polycarboxylate and / or sodium polyacrylate; the thickener is carboxymethyl cellulose and / or hydroxyethyl cellulose.

6. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 1, characterized in that, The vermiculite lithium battery fire extinguishing agent also includes a wetting agent, a defoamer, a preservative, and a pH adjuster. The wetting agent is used at a mass percentage of 0.05%-0.2%, the defoamer at a mass percentage of 0.1%-0.5%, the preservative at a mass percentage of 0.05%-0.2%, and the pH value of the vermiculite lithium battery fire extinguishing agent is 7.5-8.

5.

7. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 6, characterized in that, The wetting agent is an organosilicone surfactant; the defoamer is an organosilicone defoamer emulsion; the preservative is an isothiazolinone compound; and the pH adjuster is ammonia.

8. The preparation method of vermiculite lithium battery fire extinguishing agent based on synchronous modification process according to claim 6, characterized in that, The method for preparing the vermiculite lithium battery fire extinguishing agent by mixing modified vermiculite, dispersant, thickener and water is as follows: Add preservative, wetting agent, dispersant and half the amount of defoamer to water in sequence, and stir at low speed at 200-400 rpm until homogeneous to obtain the first mixture system; Add a pH adjuster to the first mixture to precisely adjust the pH of the system to a slightly alkaline environment of 7.5-8.5, thus obtaining the second mixture. Slowly add the thickener to the second mixture and immediately increase the rotation speed to 1500-3500 rpm for high-speed shear dispersion for 10-30 minutes until a uniform, transparent, particle-free colloidal solution is formed, thus obtaining the third mixture. At a stirring speed of 400-800 rpm, slowly add modified vermiculite to the third mixing system. After the modified vermiculite is added, adjust the stirring speed to 800-1500 rpm and disperse for 10-20 minutes to ensure that the vermiculite particles are fully wetted and dispersed, thus obtaining the fourth mixing system. At a stirring speed of 200-400 rpm, the remaining defoamer was added to the fourth mixing system, and defoaming was carried out for 5-10 minutes. The pH value and viscosity were measured, and the viscosity was finely adjusted to the target viscosity with water to obtain the vermiculite lithium battery fire extinguishing agent.

9. A vermiculite-lithium battery fire extinguishing agent based on a simultaneous modification process, characterized in that, Prepared using the preparation method according to any one of claims 1-8.

10. The application of the vermiculite lithium battery fire extinguishing agent based on synchronous modification process as described in claim 9 in lithium battery fire prevention and extinguishing.

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