A fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires and its preparation method

Abstract

The present invention relates to the technical field of fire extinguishing agents, and specifically proposes a fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires, and a method for its configuration. The fire extinguishing agent includes fire extinguishing microcapsules and aerogels. The present invention uses fire extinguishing microcapsules and aerogels as fire extinguishing agents with the main components. The fire extinguishing material is wrapped in the microcapsule structure, which can improve the storage stability and use stability of the wrapped fire extinguishing material. The aerogel structure can isolate the microcapsules to avoid microcapsule agglomeration, which helps to improve the dispersion performance of the microcapsules, so that they are evenly dispersed during fire extinguishing, achieving a good fire extinguishing effect. The aerogel has a low density, a large specific surface area, and a good thermal insulation effect. It can provide better adhesion performance. When targeting lithium battery fires at different locations, it can better adhere to the fire source location, and can isolate the heat at the fire source, effectively reducing the probability of thermal runaway of the lithium battery.

Description

Technical Field

[0001] The present invention relates to the technical field of fire extinguishing agents, and in particular to a fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires and a method for configuring the same. Background Art

[0002] With the rapid development of new energy vehicles and lithium battery technology, lithium batteries are widely used as a primary energy storage device. However, lithium batteries can experience thermal runaway during charging, discharging, or when affected by external factors, leading to fires or explosions, posing a serious threat to personal and property safety. Traditional fire extinguishing agents, such as water and foam, are effective in extinguishing Class A and Class B fires, but have limited effectiveness against lithium battery fires. Furthermore, conventional fire extinguishing agents often lose their effectiveness at high temperatures and cannot meet the special firefighting needs of new energy vehicles.

[0003] In view of the characteristics of lithium battery fires, many researchers have begun to explore new fire extinguishing agents. Among them, perfluorinated compounds have attracted attention due to their excellent fire extinguishing properties, especially perfluorohexanone, which can quickly reduce the flame temperature and effectively isolate oxygen. However, perfluorohexanone has a low specific heat capacity and limited heat absorption during gasification. When it comes to Class A or Class B fires, it can generally achieve good fire extinguishing effects. However, when it comes to lithium battery fires, due to the high energy density of lithium batteries, when a lithium battery fire occurs, it is usually accompanied by thermal runaway. A large amount of heat and gas jets will be generated inside the lithium battery, which will weaken the fire extinguishing advantage of perfluorohexanone. In the process of lithium battery explosion, perfluorohexanone may even be pushed away from the fire source, and perfluorohexanone cannot directly act on the fire source.

[0004] In response to the above-mentioned shortcomings, some existing technologies have adopted different technical solutions. For example, perfluorohexanone is formed into microcapsules, and the structural stability of the microcapsules is used to transport perfluorohexanone to the location of the fire source of the lithium battery or even to the interior, thereby cooling the interior. Some further improved solutions combine microcapsules containing perfluorohexanone with other media such as hydrogels to further increase the upper limit of heat absorption.

[0005] However, hydrogels are difficult to effectively adhere to in some specific scenarios. For example, when the location where fire needs to be extinguished is not flat, the hydrogel is more likely to fall off due to its higher density and cannot be effectively attached. This not only directly affects the working efficiency of the hydrogel, but also affects the fire extinguishing effect of the microcapsules entrained therein. Summary of the Invention

[0006] In view of this, the present invention proposes a fire extinguishing agent and its configuration method that has a more reasonable design and can be used for Class A, Class B and lithium battery fires.

[0007] The technical solution of the present invention is achieved as follows: The present invention provides a fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires, and the fire extinguishing agent includes fire extinguishing microcapsules and aerogels.

[0008] In some embodiments, the fire extinguishing microcapsule includes a core material and a shell, the core material is perfluorohexanone, the shell material is polyethylene terephthalate modified with aluminum oxide nanoparticles, and the core material accounts for 40-50% of the total mass of the microcapsule.

[0009] In some embodiments, the method for preparing the fire extinguishing microcapsules comprises:

[0010] Core material preparation: perfluorohexanone is added dropwise to the stirred aqueous phase to form a core material emulsion with a mass concentration of 40%-50%. The aqueous phase is a Tween-80 aqueous solution with a mass concentration of 0.5%-2.0%.

[0011] Shell material preparation: dissolve polyethylene terephthalate in ethyl acetate, add aluminum oxide nanoparticles, and stir evenly to obtain a shell material suspension;

[0012] Preparation of microcapsules: add the shell material suspension to the stirred core material emulsion. After the addition is complete, add glutaraldehyde under stirring to carry out cross-linking reaction, then heat to 60-80℃, keep stirring for 2-4 hours, filter, wash and dry to obtain fire-extinguishing microcapsules.

[0013] In some embodiments, during the core material preparation, the stirring speed of the aqueous phase is 5000-10000 rpm.

[0014] In some embodiments, the concentration of polyethylene terephthalate in the shell material suspension is 5%-10%, and the concentration of aluminum oxide nanoparticles in the shell material suspension is 30%-40%.

[0015] In some embodiments, the volume ratio of the shell material suspension to the core material emulsion is 1:(1-3).

[0016] In some embodiments, the aerogel is a silica-based aerogel.

[0017] In some embodiments, the method for preparing the aerogel comprises:

[0018] Preparation of sol: After tetraethyloxysilane and ethanol are mixed and stirred evenly, hydrochloric acid is added to adjust the pH value to 2-3, and water is added at the same time. Stir and react for 20-40 minutes to obtain a sol;

[0019] Gel preparation: Add ammonia water to the sol, adjust the pH to 5-6, stir and react for 12-24 hours, and let it stand at 30-50℃ for 24 hours to obtain a gel;

[0020] Solvent replacement: Soak the gel in ethanol for 12-24 hours, and repeat the above soaking steps 3-5 times;

[0021] Drying: The gel after solvent replacement is immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state, and then the carbon dioxide is slowly released to complete drying to obtain aerogel. After the aerogel is crushed, aerogel particles with an average particle size of 10-100μm are obtained.

[0022] In some embodiments, the solvent replacement step further comprises adding an aqueous solution of potassium carbonate to the ethanol.

[0023] In a second aspect, the present invention further provides a method for configuring the fire extinguishing agent, comprising the following steps:

[0024] Step 1: Pour the dry aerogel powder into the hopper of the electrostatic spraying equipment, spray the aerogel powder onto the surface of the fire extinguishing microcapsules at an electrostatic voltage of 50-70kV and an air pressure of 0.1-0.3MPa. The spraying distance is 15-30cm and the spraying time is 3-5s.

[0025] Step 2: After spraying, the composite material obtained after spraying is dried at 40-60° C. for 12-24 hours to obtain a fire extinguishing agent.

[0026] The mass ratio of fire extinguishing microcapsules to aerogel powder is (2.5-8):1

[0027] The present invention has the following beneficial effects compared to the prior art:

[0028] The present invention adopts fire extinguishing microcapsules and aerogels as the main components of the fire extinguishing agent. The fire extinguishing material is wrapped in the microcapsule structure, which can improve the storage stability and usage stability of the wrapped fire extinguishing material, and effectively avoid the fire extinguishing material being driven away from the fire source by external force during Class A and Class B fires in lithium batteries or other special scenarios, resulting in the problem of being unable to extinguish the fire source in time. Secondly, the aerogel structure can isolate the microcapsules to avoid microcapsule agglomeration, which helps to improve the dispersion performance of the microcapsules, so that they are evenly dispersed during fire extinguishing and achieve good fire extinguishing effect. Thirdly, the aerogel has a low density, a large specific surface area, and a good thermal insulation effect, and can provide better adhesion performance. When targeting lithium battery fires at different locations, it can better adhere to the fire source location and can isolate the heat at the fire source, effectively reducing the probability of thermal runaway of the lithium battery. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0031] Unless otherwise specified, the methods used in the following examples are conventional methods. The materials, reagents, and instruments used are conventional materials, reagents, and instruments in the art, unless otherwise specified, and can be obtained commercially by those skilled in the art.

[0032] When an amount, concentration or other value or parameter is expressed as a range, a preferred range or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within the range. In the present specification and claims, range definitions may be combined and / or interchanged, and if not otherwise stated, such ranges include all subranges contained therein.

[0033] Hydrogel has a high density and viscosity. When applied to non-planar or vertical surfaces, gravity causes it to easily slide off the surface and cannot continue to adhere to the fire source, affecting its fire extinguishing efficiency.

[0034] Aerogel is an extremely lightweight material with a very low density, typically hundreds of times lighter than hydrogel. Its low density means that even when applied in vertical or non-planar locations, aerogel particles can effectively adhere to the surface of the fire source, rather than falling due to gravity like hydrogel does. This property ensures that the fire extinguishing agent maintains good stability on complex terrain or structures. Aerogel's porous structure possesses strong surface adsorption capacity. Its large specific surface area allows it to firmly adhere to a variety of surfaces. Even with irregular surfaces, aerogel particles can be evenly attached through electrostatic spraying or other means, enhancing the effectiveness of the fire extinguishing agent in non-planar locations.

[0035] Not only is the hydrogel easy to fall off, it also affects the adhesion and release of the fire extinguishing agent (such as microcapsules) contained within it, resulting in the inability to release the fire extinguishing agent stably for a long time, thereby reducing the overall fire extinguishing efficiency.

[0036] The present invention uses a composite technology of aerogel and microcapsules to replace hydrogels, ensuring that the microcapsules can firmly adhere to the surface of the fire source through the adhesion of the aerogel. The low density, stability and porosity of the aerogel enable it to effectively adhere to various surfaces, avoiding the problem of fire extinguishing agent failure caused by the falling of the hydrogel. Aerogel can not only enhance the adhesion of the microcapsules, but its porous structure can also provide thermal insulation protection for the microcapsules, extend the working time of the microcapsules, and ensure that the fire extinguishing agent (such as perfluorohexanone) can be continuously and stably released around the fire source. Compared with hydrogel, this composite structure of aerogel greatly enhances the durability and fire extinguishing efficiency of the fire extinguishing agent.

[0037] In some further solutions, the shell material also contains aluminum oxide nanoparticles. PET is a polymer commonly used in industrial and high-performance products with excellent heat resistance and mechanical strength. As the shell material of the microcapsule, PET can maintain its structural stability under high temperature conditions, preventing the microcapsules from being thermally damaged in the early stages of a fire, ensuring that the fire extinguishing agent can be released at the right time. The addition of aluminum oxide nanoparticles to PET can significantly improve its high temperature resistance and resistance to thermal decomposition. Aluminum oxide has a very high melting point (approximately 2072°C), which can enhance the tolerance of microcapsules in high-temperature fire scenarios and prevent the microcapsules from rupturing prematurely. At the same time, the porous structure formed by aluminum oxide nanoparticles in the shell material can further enhance the adhesion of the microcapsules to complex surfaces (such as the surface of a battery pack), ensuring that the fire extinguishing agent can effectively cover the fire source. Through the high-temperature stability of the shell material, the fire-extinguishing microcapsules can achieve controlled release. That is, as the fire temperature gradually increases, the shell will slowly decompose, gradually releasing the perfluorohexanone inside. This controlled release mechanism ensures that the fire extinguishing agent is not exhausted all at once, but is released according to the temperature changes of the fire source, providing a continuous fire extinguishing effect.

[0038] The preparation method of the fire extinguishing microcapsule comprises:

[0039] Core material preparation: perfluorohexanone is added dropwise to the stirred aqueous phase to form a core material emulsion, wherein the aqueous phase is a Tween-80 aqueous solution with a mass concentration of 0.5%-2.0%;

[0040] Shell material preparation: dissolve polyethylene terephthalate in ethyl acetate, add aluminum oxide nanoparticles, and stir evenly to obtain a shell material suspension;

[0041] Preparation of microcapsules: add the shell material suspension to the stirred core material emulsion. After the addition is complete, add glutaraldehyde under stirring to carry out cross-linking reaction, then heat to 60-80℃, keep stirring for 2-4 hours, filter, wash and dry to obtain fire-extinguishing microcapsules.

[0042] Using Tween-80 as a surfactant, an oil-in-water (O / W) emulsion is formed, and perfluorohexanone is evenly dispersed into fine droplets in the aqueous phase, ensuring that the core material is evenly distributed within the microcapsules. Alumina nanoparticles are added to the PET solution at a mass ratio of 30%-40% and stirred evenly to form a shell material suspension. Alumina nanoparticles can improve the shell material's high-temperature resistance and adhesion, making it more stable in high-temperature scenarios such as lithium battery fires. The prepared shell material suspension is added dropwise to the stirring core material emulsion. This dropwise addition ensures that the shell material is evenly coated on the surface of the perfluorohexanone droplets, forming a preliminary microcapsule. During the coating process, glutaraldehyde is added as a crosslinking agent to promote crosslinking reactions between PET molecules, thereby improving the structural strength and stability of the shell material. The crosslinking reaction prevents the shell material from easily breaking at high temperatures and enhances the mechanical properties of the microcapsules. The microcapsule mixture is heated to 60-80°C and stirred at this temperature for 2-4 hours to ensure the crosslinking reaction is complete and further solidify the shell material. This process helps to form a complete and stable microcapsule structure.

[0043] During the core material preparation, the stirring speed of the aqueous phase is 5000-10000 rpm.

[0044] Perfluorohexanone, the core material, is a hydrophobic substance, while the aqueous phase is a hydrophilic system. To ensure that the perfluorohexanone is evenly dispersed in the aqueous phase to form fine droplets, high-speed stirring provides sufficient shear force to help the oil phase perfluorohexanone form uniformly dispersed droplets in the aqueous phase. By adjusting the stirring speed between 5000-10000 rpm, the particle size of the oil droplets in the emulsion can be effectively controlled, preventing the agglomeration of large droplets. These fine droplets provide better conditions for subsequent shell coating, ensuring that the shell material evenly covers the core material surface.

[0045] The concentration of polyethylene terephthalate in the shell material suspension is 5%-10%, and the concentration of aluminum oxide nanoparticles in the shell material suspension is 30%-40%.

[0046] The volume ratio of the shell material suspension to the core material emulsion is 1:(1-3).

[0047] Composed of ethyl acetate, polyethylene terephthalate (PET), and aluminum oxide nanoparticles, the shell of the microcapsule primarily ensures heat resistance, mechanical strength, and controlled release properties. Perfluorohexanone (a fire extinguishing agent) is dispersed in a Tween-80 aqueous solution to form a stable emulsion, which primarily provides the core material of the fire extinguishing agent. Adjusting the volume ratio of the shell suspension to the core emulsion, along with the speed and intensity of the shell suspension addition, allows for precise control of the microcapsule structure. Adjusting the volume ratio is key to optimizing microcapsule performance, determining shell thickness, core content, and ultimately, the fire extinguishing agent release characteristics. A shell suspension to core emulsion volume ratio of 1:(1-3) provides flexible microcapsule structural adjustments, enabling the fire extinguishing agent to adapt to different fire types and scenarios. By controlling the volume ratio, the shell thickness, core content, and release rate of the microcapsules can be balanced, ensuring the fire extinguishing agent exhibits advantages such as long-lasting protection, rapid response, or balanced performance in different scenarios. This design provides a more adaptable and efficient solution for microcapsule fire extinguishing agents in dealing with complex fires (such as lithium battery fires).

[0048] The aerogel is a silicon-based aerogel.

[0049] The preparation method of the aerogel comprises:

[0050] Preparation of sol: After tetraethyloxysilane and ethanol are mixed and stirred evenly, hydrochloric acid is added to adjust the pH value to 2-3, and water is added at the same time. Stir and react for 20-40 minutes to obtain a sol;

[0051] Gel preparation: Add ammonia water to the sol, adjust the pH to 5-6, stir and react for 12-24 hours, and let it stand at 30-50℃ for 24 hours to obtain a gel;

[0052] Solvent replacement: Soak the gel in ethanol for 12-24 hours, and repeat the above soaking steps 3-5 times;

[0053] Drying: The gel after solvent replacement is immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state, and then the carbon dioxide is slowly released to complete drying to obtain aerogel. After the aerogel is crushed, aerogel particles with an average particle size of 10-100μm are obtained.

[0054] The solvent replacement step further includes adding an aqueous solution of potassium carbonate to the ethanol.

[0055] Potassium carbonate can absorb a large amount of heat through phase change under high temperature conditions. Its heat absorption process helps to quickly reduce the temperature in the fire environment, thereby suppressing the spread of fire. At higher temperatures, potassium carbonate can also undergo decomposition reactions, further absorbing heat. During the solvent replacement process of the aerosol, potassium carbonate in water is gradually introduced into ethanol, and then potassium carbonate is introduced into the pore structure of the aerogel through the ethanol carrier. The potassium carbonate solution can fully penetrate into the porous structure of the aerogel, ensuring that potassium carbonate is evenly distributed inside and on the surface of the aerogel to form a composite material. This uniform distribution can maximize the heat absorption effect of potassium carbonate and respond quickly when a fire occurs.

[0056] By introducing potassium carbonate into the porous structure of the aerogel, the composite material not only insulates external heat sources through the aerogel's low thermal conductivity, but also achieves multi-layered cooling of the inner and outer layers through the potassium carbonate's phase transition and heat absorption process, thereby achieving a better cooling effect in fire environments. The addition of potassium carbonate enhances the aerogel's heat absorption capacity, making it more adaptable to high-temperature, high-energy-density fire scenarios, such as lithium battery fires. In the face of severe thermal runaway, the material can effectively contain the spread of fire by rapidly absorbing heat.

[0057] A method for preparing a fire extinguishing agent for extinguishing Class A, Class B, and lithium battery fires comprises the following steps:

[0058] Step 1: Pour the dry aerogel powder into the hopper of the electrostatic spraying equipment, spray the aerogel powder onto the surface of the fire extinguishing microcapsules at an electrostatic voltage of 50-70kV and an air pressure of 0.1-0.3MPa. The spraying distance is 15-30cm and the spraying time is 3-5s.

[0059] Step 2: After spraying, the composite material obtained after spraying is dried at 40-60° C. for 12-24 hours to obtain a fire extinguishing agent.

[0060] Electrostatic spraying uses the principle of electrostatic adsorption to evenly adhere charged aerogel powder to the surface of the microcapsules, forming a stable aerogel coating. This coating not only enhances the thermal insulation properties of the microcapsules but also improves their overall heat absorption efficiency. Aerogel's ultra-low thermal conductivity and porous structure enable it to effectively block heat transfer from fire sources. Microcapsule composites incorporating aerogel can provide more effective protection in fire environments, particularly in high-temperature scenarios such as lithium battery fires, where they exhibit a significant cooling effect. Low-temperature drying prevents damage to the microcapsule structure while maintaining the integrity of the aerogel and avoiding secondary decomposition at high temperatures.

[0061] Example 1

[0062] Preparation of fire extinguishing microcapsules:

[0063] Perfluorohexanone was added dropwise to the aqueous phase at a stirring speed of 8000 rpm to form a core material emulsion with a mass concentration of 45%, and the aqueous phase was a Tween-80 aqueous solution with a mass concentration of 1%;

[0064] Polyethylene terephthalate was dissolved in ethyl acetate, and aluminum oxide nanoparticles with an average particle size of 50 nm were added and stirred to obtain a shell material suspension. The concentration of polyethylene terephthalate in the shell material suspension was 8%, and the concentration of aluminum oxide nanoparticles in the shell material suspension was 35%.

[0065] The shell material suspension was added dropwise to the core material emulsion at a stirring speed of 8000 rpm. After the addition was completed, glutaraldehyde was added under stirring to carry out a cross-linking reaction. The mixture was then heated to 70°C and stirred for 3 hours. The mixture was filtered, washed, and dried to obtain fire-extinguishing microcapsules. The volume ratio of the shell material suspension to the core material emulsion was 1:2.

[0066] Preparation of silica-based aerogel:

[0067] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0068] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0069] Soak the gel in ethanol for 18 h, and repeat the above soaking steps 4 times;

[0070] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0071] Preparation of fire extinguishing agent:

[0072] 100 g of dried aerogel particles were poured into the hopper of the electrostatic spraying equipment, and the aerogel powder was sprayed onto the surface of 500 g of fire extinguishing microcapsules at an electrostatic voltage of 60 kV and an air pressure of 0.2 MPa. The spraying distance was 20 cm, the spraying angle was 90°, and the spraying time was 4 s. During the spraying process, the microcapsules were stirred at 100 rpm. After the spraying was completed, the composite material obtained after spraying was dried at 50°C for 20 h to obtain a fire extinguishing agent.

[0073] Example 2

[0074] Preparation of fire extinguishing microcapsules:

[0075] Perfluorohexanone was added dropwise to the aqueous phase at a stirring speed of 5000 rpm to form a core material emulsion with a mass concentration of 40%, and the aqueous phase was a Tween-80 aqueous solution with a mass concentration of 0.5%;

[0076] Polyethylene terephthalate was dissolved in ethyl acetate, and aluminum oxide nanoparticles with an average particle size of 50 nm were added and stirred to obtain a shell material suspension. The concentration of polyethylene terephthalate in the shell material suspension was 5%, and the concentration of aluminum oxide nanoparticles in the shell material suspension was 30%.

[0077] The shell material suspension was added dropwise to the core material emulsion at a stirring speed of 5000 rpm. After the addition was completed, glutaraldehyde was added under stirring to carry out a cross-linking reaction. The mixture was then heated to 60°C and stirred for 4 hours. The mixture was filtered, washed, and dried to obtain fire-extinguishing microcapsules. The volume ratio of the shell material suspension to the core material emulsion was 1:3.

[0078] Preparation of silica-based aerogel:

[0079] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:3 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.9. At the same time, water 3 times the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 40 minutes to obtain a sol;

[0080] Ammonia water was added to the sol to adjust the pH value to 5.0, and the mixture was stirred for 20 h and allowed to stand at 30°C for 18 h to obtain a gel;

[0081] Soak the gel in ethanol for 12 h, and repeat the above soaking steps 5 times;

[0082] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0083] Preparation of fire extinguishing agent:

[0084] 100 g of dried aerogel particles were poured into the hopper of the electrostatic spraying equipment. The aerogel powder was sprayed onto the surface of 250 g of fire extinguishing microcapsules at an electrostatic voltage of 70 kV and an air pressure of 0.1 MPa. The spraying distance was 15 cm, the spraying angle was 90°, and the spraying time was 3 s. During the spraying process, the microcapsules were stirred at 100 rpm. After the spraying was completed, the composite material obtained after spraying was dried at 40 ° C for 24 hours to obtain a fire extinguishing agent.

[0085] Example 3

[0086] Preparation of fire extinguishing microcapsules:

[0087] Perfluorohexanone was added dropwise to the aqueous phase at a stirring speed of 10,000 rpm to form a core material emulsion with a mass concentration of 40%, and the aqueous phase was a Tween-80 aqueous solution with a mass concentration of 2%;

[0088] Polyethylene terephthalate was dissolved in ethyl acetate, and aluminum oxide nanoparticles with an average particle size of 50 nm were added and stirred to obtain a shell material suspension. The concentration of polyethylene terephthalate in the shell material suspension was 10%, and the concentration of aluminum oxide nanoparticles in the shell material suspension was 40%.

[0089] The shell material suspension was added dropwise to the core material emulsion at a stirring speed of 10,000 rpm. After the addition was completed, glutaraldehyde was added under stirring to carry out a cross-linking reaction. The mixture was then heated to 80°C and stirred for 2 hours. The mixture was filtered, washed, and dried to obtain fire-extinguishing microcapsules. The volume ratio of the shell material suspension to the core material emulsion was 1:1.

[0090] Preparation of silica-based aerogel:

[0091] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:5 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.0. At the same time, water 4 times the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 40 minutes to obtain a sol;

[0092] Ammonia water was added to the sol to adjust the pH to 6.0, and the mixture was stirred for 12 h and allowed to stand at 50°C for 12 h to obtain a gel;

[0093] Soak the gel in ethanol for 24 h, and repeat the above soaking step 3 times;

[0094] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0095] Preparation of fire extinguishing agent:

[0096] 100 g of dried aerogel particles were poured into the hopper of the electrostatic spraying equipment, and the aerogel powder was sprayed onto the surface of 800 g of fire extinguishing microcapsules at an electrostatic voltage of 50 kV and an air pressure of 0.3 MPa. The spraying distance was 30 cm, the spraying angle was 90°, and the spraying time was 5 s. During the spraying process, the microcapsules were stirred at 100 rpm. After the spraying was completed, the composite material obtained after spraying was dried at 60 ° C for 12 h to obtain a fire extinguishing agent.

[0097] Example 4

[0098] On the basis of Example 1, keeping other conditions unchanged, the fire extinguishing agent was prepared by stirring and mixing 500 g of fire extinguishing microcapsules and 100 g of dry aerogel powder at a speed of 100 rpm for 10 seconds to obtain the fire extinguishing agent.

[0099] Example 5

[0100] On the basis of Example 1, keeping other conditions unchanged, the preparation method of silicon-based aerogel is as follows:

[0101] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0102] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0103] Soak the gel in an ethanol solution for 18 hours. The ethanol solution is a mixture of 10 wt% potassium carbonate aqueous solution and ethanol in a volume ratio of 1:2. Repeat this soaking step four times.

[0104] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0105] Example 6

[0106] On the basis of Example 1, keeping other conditions unchanged, the preparation method of silicon-based aerogel is as follows:

[0107] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0108] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0109] Soak the gel in an ethanol solution for 18 hours. The ethanol solution is a mixture of 10 wt% potassium carbonate aqueous solution and ethanol in a volume ratio of 1:2. Repeat this soaking step four times.

[0110] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0111] The fire extinguishing agent is prepared by mixing 500 g of fire extinguishing microcapsules with 100 g of dry aerogel powder at a rotation speed of 100 rpm for 10 seconds to obtain the fire extinguishing agent.

[0112] Example 7

[0113] On the basis of Example 1, keeping other conditions unchanged, the preparation method of silicon-based aerogel is as follows:

[0114] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0115] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0116] Soak the gel in an ethanol solution for 18 hours. The ethanol solution is a mixture of 10 wt% potassium carbonate aqueous solution and ethanol in a volume ratio of 1:2. Repeat this soaking step four times.

[0117] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0118] Comparative Example 1

[0119] Preparation of fire extinguishing microcapsules:

[0120] Perfluorohexanone was added dropwise to the aqueous phase at a stirring speed of 8000 rpm to form a core material emulsion with a mass concentration of 45%, and the aqueous phase was a Tween-80 aqueous solution with a mass concentration of 1%;

[0121] Polyethylene terephthalate was dissolved in ethyl acetate, and aluminum oxide nanoparticles with an average particle size of 50 nm were added and stirred to obtain a shell material suspension. The concentration of polyethylene terephthalate in the shell material suspension was 8%, and the concentration of aluminum oxide nanoparticles in the shell material suspension was 35%.

[0122] The shell material suspension was added dropwise to the core material emulsion at a stirring speed of 8000 rpm. After the addition was completed, glutaraldehyde was added under stirring to carry out a cross-linking reaction. The mixture was then heated to 70°C and stirred for 3 hours. The mixture was filtered, washed, and dried to obtain fire-extinguishing microcapsules. The volume ratio of the shell material suspension to the core material emulsion was 1:2.

[0123] The fire extinguishing agent consists only of fire extinguishing microcapsules.

[0124] Comparative Example 2

[0125] Preparation of silica-based aerogel:

[0126] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0127] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0128] Soak the gel in ethanol for 18 h, and repeat the above soaking steps 4 times;

[0129] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0130] The extinguishing agent consists solely of silica-based aerogel.

[0131] Comparative Example 3

[0132] Preparation of silica-based aerogel:

[0133] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0134] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0135] Soak the gel in an ethanol solution for 18 hours. The ethanol solution is a mixture of 10 wt% potassium carbonate aqueous solution and ethanol in a volume ratio of 1:2. Repeat this soaking step four times.

[0136] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0137] The extinguishing agent consists solely of aerogel particles.

[0138] Comparative Example 4

[0139] Preparation of silica-based aerogel:

[0140] Tetraethyloxysilane and ethanol were mixed in a mass ratio of 1:4 and stirred evenly, and then hydrochloric acid was added to adjust the pH value to 2.4. At the same time, water twice the volume of tetraethyloxysilane was added, and the mixture was stirred and reacted for 30 minutes to obtain a sol;

[0141] Ammonia water was added to the sol to adjust the pH to 5.5, and the mixture was stirred for 20 h and allowed to stand at 40°C for 24 h to obtain a gel;

[0142] Soak the gel in ethanol for 18 h, and repeat the above soaking steps 4 times;

[0143] The gel after solvent replacement was immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state (31°C, 7.38MPa), and then the carbon dioxide was slowly released to complete drying to obtain aerogel. After the aerogel was crushed, aerogel particles with an average particle size of 50μm were obtained.

[0144] The fire extinguishing agent is obtained by mixing aerogel particles and potassium carbonate in a mass ratio of 1:1.

[0145] In order to further verify the fire extinguishing effect of the technical solution of the present application, the fire extinguishing agents prepared in the above examples and comparative examples were subjected to the following performance tests:

[0146] 1. Fire extinguishing efficiency test:

[0147] Prepare a fire source:

[0148] Class A fire source: wood;

[0149] Class B fire source: gasoline;

[0150] Lithium battery fire source: ternary battery pack;

[0151] Thermocouple temperature sensors are placed around the fire source to monitor the temperature changes around the center of the fire source.

[0152] Fire extinguishing agent application: For Class A and Class B fire sources, apply the fire extinguishing agent 10 seconds after the fire source initially burns and measure the flame extinguishing time. For lithium battery fire sources, apply the fire extinguishing agent after the battery thermal runaway is triggered and record the fire extinguishing time and heat source temperature change.

[0153] 2. High temperature resistance test:

[0154] A lithium battery fire scenario was simulated, initiating thermal runaway and requiring the fire source temperature to reach over 700°C. The same amount of fire extinguishing agent was applied after the fire source reached 700°C, and the agent's duration of operation and stability at high temperatures were tested. The morphological changes of the fire-extinguishing microcapsules and aerogel composites at high temperatures were observed, and the release rate of the fire extinguishing agent and any premature rupture or failure of the materials were recorded. The duration of the fire extinguishing agent's effectiveness in high-temperature environments (from application until failure or reignition of the fire source) was recorded.

[0155] 3. Thermal insulation performance test:

[0156] The thermal insulation effectiveness of the fire extinguishing agents in each example and comparative example was evaluated, particularly their ability to isolate the area surrounding the fire source. A high-temperature fire source was simulated, set at 500-800°C, simulating a lithium battery fire or a Class B fire. Multiple temperature sensors were placed around the fire source at distances of 5cm, 10cm, 15cm, and 20cm. After applying the fire extinguishing agent, the temperature changes at the fire source and surrounding area were continuously monitored.

[0157] Adhesion and long-term effectiveness test:

[0158] Test the adhesion of fire extinguishing agents on different surfaces (especially vertical surfaces and irregular surfaces) and the continuous working time of the fire extinguishing agents to evaluate the long-term fire extinguishing ability of the materials.

[0159] The specific data results are shown in the following table:

[0160] project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Class A fire extinguishing time / s 16.3 17.5 15.2 25.6 13.8 13.6 13.3 Class B fire extinguishing time / s 20.1 21.4 19.3 30.5 17.2 16.9 15.7 Lithium battery fire extinguishing time / s 55.7 60.4 51.8 85.9 40.2 38.6 37.9 High temperature resistant effective working time / s 72.4 66.8 81.5 61.3 112.7 116.5 119.3 Temperature drop near the fire source (5cm) / ℃ 181.6 172.3 186.8 163.4 223.5 227.9 229.6 Temperature drop near the fire source (20cm) / ℃ 51.8 47.3 54.5 41.9 75.7 77.9 79.1 Adhesion / min 12.3 11.5 13.2 7.6 15.8 16.4 17.3 Long-term effect / min 22.6 20.7 23.5 13.4 32.9 34.6 36.2

[0161] project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Class A fire extinguishing time / s 35.8 32.7 33.4 31.6 Class B fire extinguishing time / s 40.4 36.2 37.8 35.9 Lithium battery fire extinguishing time / s 125.3 91.7 94.6 92.3 High temperature resistant effective working time / s 44.7 71.3 73.8 70.2 Temperature drop near the fire source (5cm) / ℃ 121.8 172.9 175.4 173.8 Temperature drop near the fire source (20cm) / ℃ 34.5 50.2 51.8 49.6 Adhesion / min 5.2 7.1 8.2 7.5 Long-term effect / min 10.8 13.5 14.1 13.7

[0162] Fire extinguishing efficiency:

[0163] Examples 5-7 (composite potassium carbonate aerogel): extinguished fires in 13.3-13.8 seconds for Class A fires, 15.7-17.2 seconds for Class B fires, and 37.9-40.2 seconds for lithium battery fires. This group of materials exhibited significantly higher fire extinguishing efficiency than the other examples.

[0164] Example 1-3: The fire extinguishing time for Class A fire source is 15.2-17.5 seconds, for Class B fire source is 19.3-21.4 seconds, and for lithium battery fire source is 51.8-60.4 seconds. Although electrostatic spraying improves uniformity, the fire extinguishing efficiency is slightly lower than that of the composite potassium carbonate material.

[0165] Example 4: Due to uneven mixing, the fire extinguishing time is longer, 25.6 seconds for Class A fire source, 30.5 seconds for Class B fire source, and 85.9 seconds for lithium battery fire source.

[0166] Comparative Example 1: Only microcapsules have poor fire extinguishing efficiency, 35.8 seconds for Class A fire source, 40.4 seconds for Class B fire source, and 125.3 seconds for lithium battery fire source.

[0167] Comparative Examples 2-4: Although aerogel is used for thermal insulation, the fire extinguishing effect is poor, with Class A fire extinguishing in 31.6-33.4 seconds, Class B fire extinguishing in 35.9-37.8 seconds, and lithium battery fire extinguishing in 91.7-94.6 seconds.

[0168] High temperature resistant new energy:

[0169] Example 5-7: The high-temperature working time is 112.7-119.3 seconds, which is very suitable for high-temperature scenarios such as lithium battery fires. The heat absorption property of the composite potassium carbonate extends the working time.

[0170] Example 1-3: The working time is 66.8-81.5 seconds, which is suitable for conventional fire sources and lithium battery fire sources, but slightly worse than compound potassium carbonate.

[0171] Example 4: Due to conventional mixing, the working time at high temperature is only 61.3 seconds.

[0172] Comparative Example 1: Failure occurs quickly at high temperatures, with a working time of only 44.7 seconds.

[0173] Comparative Examples 2-4: The aerogel provided certain high temperature resistance, and the working time was 70.2-73.8 seconds.

[0174] Thermal insulation performance:

[0175] Examples 5-7: Excellent performance, with the temperature near the fire source dropping by 223.5-229.6°C and the temperature far away dropping by 75.7-79.1°C. The potassium carbonate composite aerogel provides good thermal insulation and heat absorption capabilities.

[0176] Example 1-3: The temperature near the fire source dropped by 172.3-186.8°C, and the temperature far away dropped by 47.3-54.5°C, with good insulation effect.

[0177] Example 4: The thermal insulation effect is slightly worse, with the temperature near the fire source dropping by 163.4°C and the temperature far away dropping by 41.9°C.

[0178] Comparative Example 1: Due to the absence of aerogel, the thermal insulation effect is poor, the temperature near the fire source only drops by 121.8°C, and the temperature far away drops by 34.5°C.

[0179] Comparative Example 2-4: The thermal insulation effect is moderate, with the temperature near the fire source dropping by 170.2-175.4°C and the temperature far away dropping by 49.6-51.8°C.

[0180] Adhesion and long-term effect:

[0181] Example 5-7: The adhesion performance is the best, which can last for 15.8-17.3 minutes, and the long-term fire extinguishing ability can last for 32.9-36.2 minutes.

[0182] Example 1-3: The adhesion is good, lasting 11.5-13.2 minutes, and the long-term effect is 20.7-23.5 minutes.

[0183] Example 4: Due to poor mixing effect, the adhesion was 7.6 minutes and the long-term effect was only 13.4 minutes.

[0184] Comparative Example 1: The adhesion and long-term effect were poor, being 5.2 minutes and 10.8 minutes respectively.

[0185] Comparative Example 2-4: The adhesion is moderate, lasting for 7.1-8.2 minutes, and the long-term effect is 13.5-14.1 minutes.

[0186] Examples 5-7 performed exceptionally well in all tests, achieving optimal levels of fire extinguishing efficiency, high-temperature resistance, thermal insulation, adhesion, and long-lasting performance, making them particularly suitable for high-temperature, complex fire scenarios (such as lithium battery fires). Examples 1-3 performed well, particularly with good fire extinguishing efficiency and adhesion in conventional Class A and Class B fires.

[0187] In Example 4, the overall performance of the fire extinguishing agent is affected due to the uneven mixing method, and the effect is poor in a high-temperature environment.

[0188] Comparative Example 1 lacks the thermal insulation effect of aerogel, and has poor fire extinguishing efficiency and high temperature resistance. Comparative Examples 2-4 have improved performance, but due to the lack of chemical fire extinguishing agents, the fire extinguishing efficiency is still not ideal.

[0189] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires, characterized in that: The fire extinguishing agent includes fire extinguishing microcapsules and aerogels. The fire extinguishing microcapsules include a core material and a shell material. The core material is perfluorohexanone, and the shell material is polyethylene terephthalate modified with aluminum oxide nanoparticles. The preparation method of the aerogel includes: Preparation of sol: After tetraethyloxysilane and ethanol are mixed and stirred evenly, hydrochloric acid is added to adjust the pH value to 2-3, and water is added at the same time. Stir and react for 20-40 minutes to obtain a sol; Gel preparation: Add ammonia water to the sol, adjust the pH to 5-6, stir and react for 12-24 hours, and let it stand at 30-50℃ for 24 hours to obtain a gel; Solvent replacement: Soak the gel in ethanol, add an aqueous solution of potassium carbonate to the ethanol, soak for 12-24 hours, and repeat the soaking step 3-5 times; Drying: The gel after solvent replacement is immersed in liquid carbon dioxide, heated and pressurized to make the liquid carbon dioxide reach a supercritical state, and then the carbon dioxide is slowly released to complete drying to obtain aerogel. After the aerogel is crushed, aerogel particles with an average particle size of 10-100μm are obtained.

2. The fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires according to claim 1, characterized in that: The preparation method of the fire extinguishing microcapsule comprises: Core material preparation: perfluorohexanone is added dropwise to the stirred aqueous phase to form a core material emulsion with a mass concentration of 40%-50%. The aqueous phase is a Tween-80 aqueous solution with a mass concentration of 0.5%-2.0%. Shell material preparation: dissolve polyethylene terephthalate in ethyl acetate, add aluminum oxide nanoparticles, and stir evenly to obtain a shell material suspension; Preparation of microcapsules: add the shell material suspension to the stirred core material emulsion. After the addition is complete, add glutaraldehyde under stirring to carry out cross-linking reaction, then heat to 60-80℃, keep stirring for 2-4 hours, filter, wash and dry to obtain fire-extinguishing microcapsules.

3. The fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires according to claim 2, characterized in that: During the core material preparation, the stirring speed of the aqueous phase is 5000-10000 rpm.

4. The fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires according to claim 2, characterized in that: The concentration of polyethylene terephthalate in the shell material suspension is 5%-10%, and the concentration of aluminum oxide nanoparticles in the shell material suspension is 30%-40%.

5. The fire extinguishing agent for extinguishing Class A, Class B and lithium battery fires according to claim 2, characterized in that: The volume ratio of the shell material suspension to the core material emulsion is 1:(1-3).

6. The method for preparing a fire extinguishing agent for extinguishing Class A, Class B, and lithium battery fires according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Pour the dry aerogel powder into the hopper of the electrostatic spraying equipment, spray the aerogel powder onto the surface of the fire extinguishing microcapsules at an electrostatic voltage of 50-70kV and an air pressure of 0.1-0.3MPa. The spraying distance is 15-30cm and the spraying time is 3-5s. Step 2: After spraying, the composite material obtained after spraying is dried at 40-60° C. for 12-24 hours to obtain a fire extinguishing agent.