Fire extinguishing agent for rapidly inhibiting fire breakout of power battery as well as preparation method and use method of fire extinguishing agent

Abstract

The invention relates to a fire extinguishing agent for rapidly inhibiting fire breakout of a power battery, a preparation method and a use method, and the fire extinguishing agent comprises the following components in percentage by mass: 40-60% of aerogel powder; 30%-40% of water; 5%-15% of a functional auxiliary agent; wherein the aerogel powder comprises at least one of silicon dioxide aerogel, aluminum oxide aerogel and silicon-aluminum aerogel, the fire extinguishing agent uses carbon dioxide gas with the pressure intensity being 1-5 Mpa as injection assisting gas and a premixing medium, and carbon dioxide accounts for 40%-60% of the total volume of the mixed fire extinguishing agent; through the synergistic effect of the aerogel powder and the high-pressure carbon dioxide, an inert gas isolation layer is formed while rapid cooling is conducted, reburning is effectively prevented, the fire extinguishing agent is free of conductivity and corrosivity, the problem that efficient cooling, lasting oxygen isolation and secondary damage avoiding cannot be considered at the same time in the traditional technology is solved, and the fire extinguishing effect is good. The device has the advantages of efficient cooling, lasting oxygen isolation, prevention of re-combustion and no corrosive secondary damage.

Description

Technical Field

[0001] This application relates to the technical field of fire extinguishing agents for power batteries, and in particular to a fire extinguishing agent for rapidly suppressing fires in power batteries and a method for preparing the same. Background Technology

[0002] With the government's increasing policy and institutional support for the new energy vehicle industry, my country's electric vehicle industry has achieved rapid development. As a core component of new energy vehicles, the safety of power batteries is the cornerstone of the entire industry's sustainable development. However, due to their high energy density, lithium-ion batteries are highly susceptible to thermal runaway and fires under thermal, electrical, or mechanical abuse. Lithium-ion battery fires are characterized by high temperatures, rapid spread, easy reignition, and the release of large amounts of toxic and flammable gases, posing a severe challenge to traditional fire extinguishing technologies. Currently, existing fire extinguishing technologies for lithium-ion battery fires mainly fall into the following categories:

[0003] 1. Water-based extinguishing agents (such as pure water and water mist): Water has a high specific heat capacity and a significant cooling effect. However, it cannot effectively isolate oxygen. For thermal runaway batteries that continuously produce flammable gases, they are very likely to reignite after the flames are extinguished. At the same time, spraying large amounts of water may cause internal short circuits in the battery, exacerbating thermal runaway. For battery packs in a high-voltage state, the water medium poses a risk of electrical conductivity, threatening the safety of rescue personnel.

[0004] 2. Gaseous extinguishing agents (such as carbon dioxide and perfluorohexanone): These extinguishing agents mainly extinguish fires through asphyxiation and chemical inhibition. However, their cooling capacity is limited. For batteries that have experienced severe thermal runaway and have extremely high internal temperatures, the gas cannot quickly reduce the temperature of the battery body, and deep-seated fire sources are difficult to extinguish completely.

[0005] 3. Dry powder extinguishing agents (such as ABC dry powder): Dry powder extinguishing agents can quickly extinguish open flames. However, their residues are highly corrosive and insulating, which can cause irreversible secondary damage to the delicate circuits inside the battery pack. Furthermore, the powder is difficult to clean completely, leading to the scrapping of the entire battery pack and resulting in huge economic losses.

[0006] In summary, existing fire extinguishing solutions cannot simultaneously meet the requirements of efficient cooling, sustained oxygen isolation to prevent reignition, and no corrosive / conductive secondary damage. Summary of the Invention

[0007] To address the aforementioned shortcomings, this application provides a fire extinguishing agent for rapidly suppressing fires in power batteries, its preparation method, and its application method.

[0008] The above-mentioned objective of this application is achieved through the following technical solution:

[0009] A fire extinguishing agent for rapidly suppressing fires in power batteries, comprising, by weight percentage:

[0010] Aerogel powder 40%~60%;

[0011] Water 30%~40%;

[0012] Functional additives 5%~15%;

[0013] The aerogel powder includes at least one of silica aerogel, alumina aerogel, and silica-alumina aerogel. The extinguishing agent uses carbon dioxide gas with a pressure of 1-5 MPa as the jetting gas and premixed medium, and carbon dioxide accounts for 40%-60% of the total volume of the mixed extinguishing agent.

[0014] In a preferred embodiment, the present application may be further configured such that the functional additive includes at least one of surfactants and lithium-ion battery flame retardants.

[0015] In a preferred embodiment, the present application may be further configured such that the lithium-ion battery flame retardant is azobisisobutyrazoline hydrochloride.

[0016] In a preferred embodiment, this application may be further configured such that the surfactant comprises a fluorocarbon surfactant.

[0017] In a preferred embodiment, the aerogel powder can be further configured such that: the porosity of the aerogel powder is not less than 90%, and the specific surface area of ​​the aerogel powder is 800~1000 m². 2 / g.

[0018] The second objective of this invention is achieved through the following technical solution: a method for preparing a fire extinguishing agent for rapidly suppressing fires in power batteries, comprising the following steps:

[0019] S1: Add water to a premix tank equipped with a high-speed shear disperser according to the ratio. Add functional additives according to the ratio at a stirring speed of 200~400rpm and stir for 5~10min until they are completely dissolved.

[0020] S2: Increase the stirring speed to 2000~5000 rpm, and slowly add the aerogel powder in batches according to the ratio;

[0021] S3: Continuously shear and disperse at high speed for 20~30 minutes until a homogeneous, viscous slurry without visible particles is formed, and then seal and store at 15~25℃ for later use.

[0022] S4: The slurry prepared in step S3 is pumped into the first inlet of a static mixer with a built-in S-type turbulence unit through a corrosion-resistant pump.

[0023] S5: High-pressure carbon dioxide gas with a pressure of 1~5Mpa and a temperature of 10~20℃ is introduced into the second inlet of the static mixer;

[0024] S6: The slurry and high-pressure carbon dioxide gas are fully mixed in the static mixer to generate a three-phase mixed extinguishing agent.

[0025] In a preferred embodiment, this application may be further configured such that, in step S2, the aerogel powder is added uniformly at a rate of 1-2 kg / min.

[0026] In a preferred embodiment, this application may be further configured such that, in step S3, the viscosity of the slurry is 5000~15000 mPa·s.

[0027] The third objective of this invention is achieved through the following technical solution:

[0028] A method for using a fire extinguishing agent to rapidly suppress fires in power batteries, wherein the fire extinguishing agent is prepared using the preparation method described in Objective 2, and the method of use is as follows:

[0029] The generated three-phase mixed extinguishing agent is sprayed onto the surface of the burning lithium-ion battery through an adjustable fan-shaped nozzle at a spray rate of 500~1000g / min, and the coverage shape of the extinguishing agent is controlled by adjusting the fan-shaped nozzle.

[0030] In a preferred embodiment, this application can be further configured such that the spray angle of the fan-shaped nozzle is infinitely adjustable within the range of 30° to 90° to adapt to directional coverage of lithium-ion battery packs with different layouts.

[0031] As can be seen from the above, the fire extinguishing agent for rapidly suppressing power battery fires provided in this application, as well as its preparation and application methods, form an inert gas isolation layer while rapidly cooling through the synergistic effect of aerogel powder and high-pressure carbon dioxide, effectively preventing reignition. Moreover, the fire extinguishing agent is non-conductive and non-corrosive, solving the problem that traditional technologies cannot simultaneously achieve efficient cooling, long-term oxygen isolation, and avoidance of secondary damage. It has the advantages of efficient cooling, long-term oxygen isolation to prevent reignition, and no corrosive secondary damage. Detailed Implementation

[0032] In existing technologies, lithium-ion battery fires, due to their high energy density, pose risks of high temperatures, rapid spread, and reignition during thermal runaway, and traditional fire extinguishing techniques have significant shortcomings. Water-based extinguishing agents cannot isolate oxygen and pose a high risk of electrical conductivity; gaseous extinguishing agents have insufficient cooling capacity; and dry powder extinguishing agents leave corrosive residues. In one case, a new energy vehicle's power battery pack experienced thermal runaway during charging due to an internal short circuit. The flames spread rapidly, accompanied by the release of large amounts of flammable gas. Despite attempts to extinguish the fire with conventional extinguishing agents, the flames reignited multiple times, resulting in the complete destruction of the battery pack.

[0033] To address these issues, a fire extinguishing agent capable of simultaneously achieving rapid cooling, oxygen isolation, and no secondary damage needs to be developed. Analysis of the thermal runaway mechanism reveals the need to block heat transfer from contact with combustible materials. Aerogel materials, due to their ultra-low thermal conductivity, can serve as a thermal barrier. Combined with the heat-absorbing and evaporating properties of liquid media, a composite fire extinguishing system is formed. Carbon dioxide gas can both assist in atomization and dilute the oxygen concentration, thus constructing a gas-liquid-solid three-phase synergistic mechanism.

[0034] Therefore, this application proposes a fire extinguishing agent comprising aerogel powder, water, and functional additives, wherein the aerogel powder is selected from at least one of silica aerogel, alumina aerogel, or aluminosilicate aerogel, the water content is 30%-40%, and the functional additives content is 5%-15%. This fire extinguishing agent uses carbon dioxide gas at a pressure of 1-5 MPa as the auxiliary spray medium, with carbon dioxide comprising 40%-60% of the total volume after mixing.

[0035] Aerogel powder refers to an ultralight solid material with a nanoporous structure, a porosity of not less than 90%, and a specific surface area of ​​800-1000 m² / g, which captures free radicals generated during combustion through physical adsorption. Water, as a continuous phase medium, reduces the battery surface temperature through vaporization and heat absorption. Functional additives include surfactants or lithium-ion battery-specific flame retardants, used to improve slurry dispersion stability or inhibit chain combustion reactions. Carbon dioxide gas forms a gas-liquid two-phase flow under high pressure, enhancing the penetration ability of the extinguishing agent while reducing the ambient oxygen concentration.

[0036] Specifically, aerogel powder is uniformly suspended in the aqueous phase during high-speed shear dispersion, forming a thixotropic viscous slurry. When this slurry is turbulently mixed with high-pressure carbon dioxide in a static mixer, the aerogel particles are carried by the gas to form an aerosol state, which is then channeled through fan-shaped nozzles to create a directional fire-extinguishing mist. The carbon dioxide absorbs heat during expansion, forming a three-dimensional thermal insulation network with the aerogel, preventing heat transfer to unburned areas. The aqueous medium rapidly vaporizes upon contact with high-temperature surfaces, carrying away a significant amount of latent heat.

[0037] Compared to existing technologies, traditional water-based fire extinguishing agents cannot form a durable insulation layer, leading to reignition. In contrast, the porous framework formed by the aerogel in this solution maintains its insulating effect for an extended period. Compared to pure carbon dioxide fire extinguishing agents, the aerogel-water composite system significantly improves cooling efficiency, preventing heat buildup inside the battery. Compared to dry powder fire extinguishing agents, this solution leaves no solid residue, avoiding circuit corrosion and cleaning difficulties.

[0038] Through the above technical solution, this application effectively resolves the technical contradiction of simultaneously achieving cooling and isolation during lithium-ion battery fire suppression. The aerogel framework inhibits flame reignition while the aqueous medium continuously absorbs heat to prevent heat diffusion, and carbon dioxide synergistically enhances the penetration capability of the extinguishing agent. This composite system can maintain long-term protection after the open flame is extinguished, avoiding the risk of secondary reignition, and will not cause conductive or corrosive damage to the internal structure of the battery pack.

[0039] This application further proposes that functional additives include at least one of surfactants and lithium-ion battery flame retardants.

[0040] Surfactants are compounds that can reduce the surface tension of liquids. Fluorocarbon surfactants are commonly used, as their fluorocarbon chains possess high surface activity, enhancing the wetting and spreading ability of fire extinguishing agents on the battery surface and promoting uniform coverage of thermal runaway areas by aerogel powder. Lithium-ion battery flame retardants are substances that inhibit the redox reactions within lithium-ion batteries. Azobisisobutyrazoline hydrochloride is a common example; this compound decomposes at high temperatures to produce free radical scavengers, which can interrupt the chain-like exothermic reaction within the battery.

[0041] Specifically, the addition of surfactants enables the aerogel powder to form a stable dispersion system with the water-based medium, preventing powder agglomeration and sedimentation, and ensuring the formation of a continuous coating layer during spraying. Lithium-ion battery flame retardants directly intervene in the thermal runaway process inside the battery through chemical action, forming a dual protection mechanism based on the physical isolation of the aerogel. When the extinguishing agent comes into contact with the high-temperature battery surface, the flame retardant rapidly decomposes and reacts with the electrolyte decomposition products, inhibiting the generation of flammable gases. Simultaneously, the surfactants promote the rapid penetration of the slurry into the battery gaps.

[0042] Compared to existing technologies, traditional dry powder fire extinguishing agents rely solely on physical isolation and leave corrosive residues. This solution, however, utilizes the synergistic effect of flame retardants and surfactants to actively intervene in the electrochemical reaction while achieving physical isolation. Furthermore, all components of the extinguishing agent are biodegradable or inert, avoiding secondary damage to the battery circuitry. Compared to methods that simply use carbon dioxide for asphyxiation, this technology significantly reduces the probability of reignition through the chemical inhibition at the molecular level by flame retardants.

[0043] Through the above technical solution, this application effectively solves the technical contradiction that traditional fire extinguishing agents cannot simultaneously block the chain reaction inside the battery and achieve rapid coverage. Surfactants improve the penetration efficiency of fire extinguishing agents in complex battery structures, and flame retardants directly inhibit the flammable gases generated by the decomposition of electrolyte. The synergistic effect of the two enables the fire extinguishing agent to continue to suppress deep thermal runaway after extinguishing open flames.

[0044] This application further proposes that the flame retardant for lithium-ion batteries is azobisisobutyrazoline hydrochloride.

[0045] Azobisisobutyridine imidazoline hydrochloride is a compound containing an azo group and an imidazoline ring structure. It can be prepared through chemical synthesis, such as the condensation reaction of isobutyronitrile with hydrochloric acid. This compound decomposes at high temperatures to produce inert gases such as nitrogen, achieving flame retardancy by diluting the oxygen concentration and inhibiting free radical chain reactions.

[0046] Specifically, when the extinguishing agent comes into contact with the high-temperature battery surface, azobisisobutyrazoline hydrochloride decomposes upon heating to generate nitrogen gas, effectively reducing the oxygen concentration in the combustion zone. Simultaneously, the amino radicals in its decomposition products can capture active free radicals in the combustion reaction, inhibiting the continued chain reaction. This flame retardant can synergize with aerogel powder; for example, the flame retardant adsorbed by the aerogel can form a coating layer on the battery surface, continuously releasing flame-retardant components to prevent reignition.

[0047] Compared to existing technologies, traditional lithium-ion battery flame retardants, such as phosphorus-based flame retardants, produce corrosive acidic substances at high temperatures. In contrast, azobisisobutyrazoline hydrochloride, upon decomposition, primarily generates nitrogen gas and water-soluble salts, which do not corrode the internal circuitry of the battery. Furthermore, this compound exhibits high stability at room temperature; for example, it does not undergo hydrolysis with water or aerogels during storage.

[0048] Through the above technical solution, this application can quickly interrupt the thermal runaway reaction of lithium-ion batteries without damaging the internal structure of the battery pack. The inert gas generated by the decomposition of the flame retardant can penetrate the gaps in the battery module, suppressing the continued combustion of the internal cells, while avoiding the risk of short circuits caused by the residue of traditional dry powder fire extinguishing agents.

[0049] This application further proposes that surfactants include fluorocarbon surfactants.

[0050] Fluorocarbon surfactants are surface-active substances whose molecular structure contains fluorocarbon chains. Specifically, they can be achieved using perfluorooctyl sulfonate or perfluoropolyether compounds, where fluorine atoms in the carbon chain replace hydrogen atoms to form a high-bond-energy CF structure. In fire extinguishing agents, this substance reduces the surface tension of the slurry, enhances the wetting and spreading ability of the slurry on high-temperature metal surfaces, and simultaneously works synergistically with carbon dioxide gas to form a stable foam layer.

[0051] Specifically, fluorocarbon surfactants are uniformly dispersed in the aqueous phase during the premixing stage. When the slurry is mixed with high-pressure carbon dioxide, its molecules are oriented at the gas-liquid interface, forming a foam system with low surface tension. During spraying onto the surface of the burning battery, the foam system rapidly covers the gaps between the cells, repelling electrolyte penetration through the oleophobic properties of the fluorocarbon chains. Simultaneously, the foam layer isolates oxygen and slows heat transfer. Because the thermal decomposition temperature of fluorocarbon surfactants is higher than the thermal runaway temperature of lithium-ion batteries, the foam layer maintains its structural integrity even under high-temperature conditions.

[0052] Compared to existing technologies, traditional fire extinguishing agents use ordinary hydrocarbon surfactants that are prone to decomposition and inactivation at high temperatures, and the residues may increase the conductivity of the solution. In contrast, fluorocarbon surfactants maintain stable activity in high-temperature environments, and their decomposition products are gaseous substances that do not form conductive residues inside the battery pack, thus avoiding the risk of short circuits caused by surfactant carbonization.

[0053] Through the above technical solution, this application solves the problem of insufficient stability of traditional surfactants in high-temperature fire extinguishing scenarios, enabling the fire extinguishing agent foam to cover the battery thermal runaway area for a long time, effectively blocking the contact between combustible gas and oxygen, and avoiding secondary electrical faults caused by surfactant residue.

[0054] This application further proposes that the porosity of the aerogel powder is not less than 90%, and the specific surface area of ​​the aerogel powder is 800~1000m² / g.

[0055] Porosity refers to the proportion of pore volume to the total volume of an aerogel material. It can be achieved by preparing aerogel powder using supercritical drying technology. A high porosity structure significantly enhances the thermal insulation performance and gas adsorption capacity of the aerogel. Specific surface area refers to the total surface area per unit mass of aerogel powder. It can be achieved by preparing aerogel using a combination of sol-gel and template methods. A high specific surface area facilitates the formation of a more uniform dispersion system during the spraying of the fire extinguishing agent and improves the adsorption efficiency of pyrolysis products.

[0056] Specifically, the aerogel powder with a porosity of not less than 90% forms a continuous three-dimensional nanoporous network structure. When the fire extinguishing agent is sprayed onto the battery surface, this structure can effectively block the longitudinal transfer of heat and adsorb the flammable gases released during thermal runaway of the battery. The aerogel powder with a specific surface area of ​​800~1000m² / g has abundant surface active sites, which can form a stable suspension system with water-based media during high-speed shear dispersion and achieve rapid spreading and coverage under the drive of carbon dioxide gas.

[0057] Compared to existing technologies, the porous materials used in conventional fire extinguishing agents typically have a porosity of less than 85% and a specific surface area of ​​less than 500 m² / g, resulting in insufficient thermal insulation and adsorption capacity. This solution modulates the porosity and specific surface area parameters of aerogel powder to form a denser barrier layer per unit volume, while simultaneously enhancing its ability to capture pyrolysis products.

[0058] Through the above technical solution, this application can effectively block the heat transfer path during the thermal runaway process of lithium-ion batteries, suppress the secondary reaction between combustible gas and oxygen, and avoid the problem of fire extinguishing agent agglomeration and sedimentation caused by insufficient material specific surface area. Thus, it can continue to play a flame-retardant role after the open flame is extinguished and will not cause corrosive damage to the internal structure of the battery pack.

[0059] This application further proposes a preparation method comprising the following steps: adding water to a premixing tank equipped with a high-speed shear disperser in proportion; adding functional additives in proportion at a stirring speed of 200 to 400 rpm and stirring for 5 to 10 minutes until completely dissolved; increasing the stirring speed to 2000 to 5000 rpm and slowly adding aerogel powder in proportion in batches; continuously shearing and dispersing at high speed for 20 to 30 minutes until a homogeneous, viscous slurry without visible particles is formed, and storing it in a sealed environment at 15 to 25°C for later use; pumping the prepared slurry into the first inlet of a static mixer with a built-in S-type turbulence unit through a corrosion-resistant pump; introducing high-pressure carbon dioxide gas with a pressure of 1 to 5 MPa and a temperature of 10 to 20°C into the second inlet of the static mixer; allowing the slurry and high-pressure carbon dioxide gas to be fully mixed in the static mixer to generate a three-phase mixed fire extinguishing agent.

[0060] Among them, the high-speed shear disperser refers to a device that achieves uniform material dispersion through high-speed mechanical force. Specifically, it can be implemented using an industrial-grade disperser with an adjustable-speed rotor. Its function is to break down the agglomeration structure of aerogel powder through dynamic shear force, ensuring uniform slurry dispersion. The static mixer refers to a pipeline mixing device without moving parts. Specifically, it can be implemented using a metal tube structure with a built-in S-shaped turbulence unit. Its function is to promote the micro-mixing of carbon dioxide gas and slurry through the turbulence effect of fluid within the pipe. The S-shaped turbulence unit refers to a metal internal component with a continuous S-shaped baffle structure. Specifically, it can be implemented using 316L stainless steel stamped parts. Its function is to increase the gas-liquid contact area by changing the fluid flow path, thereby improving mixing efficiency.

[0061] Specifically, water and functional additives are initially dissolved in a premixing tank by low-speed stirring to avoid decomposition of the additives due to violent shearing. The stirring speed is then increased to a high-speed shearing state, and aerogel powder is added in batches to prevent localized accumulation and clumping. Continuous high-speed dispersion ensures thorough wetting of the aerogel particles, forming a stable, viscous slurry. The slurry is pumped to a static mixer via a corrosion-resistant pump, where it mixes with high-pressure carbon dioxide gas in a turbulent flow unit to form a gas-liquid-solid three-phase mixture system. Carbon dioxide serves as both the transport medium and participates in the extinguishing reaction. The mixed extinguishing agent is then uniformly atomized and sprayed through nozzles, covering the battery surface to form a heat insulation layer and suppressing the release of flammable gases.

[0062] Compared with existing technologies, traditional fire extinguishing agent preparation often employs simple mechanical stirring or gas-liquid mixing, which fails to achieve uniform dispersion of aerogel powder and stable coexistence of the three-phase system. This method solves the problems of aerogel agglomeration and uneven carbon dioxide mixing by controlling the shear rate in stages and combining the turbulence enhancement effect of a static mixer, thus ensuring the synergistic effect of the various components of the fire extinguishing agent.

[0063] Through the above technical solution, this application can prepare a fire extinguishing agent with a stable three-phase structure. After spraying, it rapidly forms a covering layer to isolate oxygen, while simultaneously reducing the battery temperature through the phase change of carbon dioxide, effectively suppressing the thermal runaway chain reaction. This method avoids the corrosion residue problem of traditional dry powder fire extinguishing agents and overcomes the deficiency of insufficient cooling capacity of single gaseous fire extinguishing agents.

[0064] This application further proposes that in step S2, the aerogel powder is added uniformly at a rate of 1~2 kg / min.

[0065] The aerogel powder addition rate refers to the mass of powder added to the premixing tank per unit time. This can be achieved using a quantitative feeding device combined with a loss-in-weight metering system. This rate range ensures the powder is fully dispersed during high-speed shearing, preventing the formation of unwetted dry powder clumps due to localized accumulation. Uniform addition refers to a linearly increasing powder feeding method over time, which can be achieved through the variable frequency speed control of the screw conveyor. This method eliminates slurry concentration fluctuations caused by intermittent feeding.

[0066] Specifically, during the preparation process, when the liquid medium in the premix tank forms a turbulent flow field under stirring at 2000-5000 rpm, the aerogel powder is continuously conveyed to the area below the liquid surface at a specific rate. This rate range forms a dynamic balance with the stirring speed, ensuring that the powder particles are promptly entrained into the shear zone while avoiding unwetted powder floating on the liquid surface due to excessive instantaneous feed. Under the action of high-speed shear force, the powder particles are fully dispersed, forming a stable solid-liquid dispersion system with the functional additive solution, thus laying the foundation for subsequent uniform mixing with carbon dioxide gas.

[0067] Compared to existing technologies, traditional powder feeding processes typically employ a one-time pouring or non-controlled feeding method, which easily leads to powder agglomeration on the liquid surface, forming "fish-eye" defects. However, by precisely controlling the feeding rate, the powder dispersion process and the liquid wetting process can be synchronized, significantly improving the uniformity and stability of the slurry.

[0068] Through the above technical solution, this application effectively solves the technical problem of aerogel powder being prone to agglomeration and uneven dispersion during high-speed mixing, ensuring that the prepared fire extinguishing agent slurry has stable viscosity and suspension characteristics, providing the necessary prerequisite for uniform mixing with carbon dioxide gas in the subsequent process, thereby ensuring that the final fire extinguishing agent product can form a uniform and dense covering layer when sprayed.

[0069] This application further proposes that in step S3, the viscosity of the slurry is 5000~15000 mPa·s.

[0070] The viscosity of the slurry refers to the internal friction generated during its flow, which can be measured using a rotational viscometer under standard test conditions. This viscosity range ensures that the slurry maintains a uniform dispersion during storage, preventing aerogel powder sedimentation or agglomeration. It also ensures that the slurry has suitable fluidity when subsequently mixed with high-pressure carbon dioxide, enabling the three-phase mixed extinguishing agent to form a stable gas-liquid-solid dispersion system.

[0071] Specifically, when the slurry viscosity is below 5000 mPa·s, the aerogel powder may settle due to the low viscosity of the dispersion medium, leading to slurry stratification. Conversely, when the viscosity is above 15000 mPa·s, the slurry's fluidity decreases, making it difficult to fully mix with carbon dioxide gas in a static mixer. By controlling the viscosity within the range of 5000~15000 mPa·s, the slurry can maintain homogeneous stability during storage and achieve turbulent contact with the gas during mixing, allowing the aerogel powder to be uniformly dispersed in both the gas and liquid phases, forming a fire extinguishing medium with a three-dimensional network structure.

[0072] Compared to existing technologies, traditional fire extinguishing agent preparation processes often neglect precise control of slurry viscosity. For example, water-based fire extinguishing agents directly use low-viscosity liquid water, resulting in the fire extinguishing agent failing to effectively adhere to the battery surface; while dry powder fire extinguishing agents suffer from powder agglomeration problems. This solution overcomes the poor dispersibility of liquid media and avoids the problem of insufficient flowability of solid powders by limiting the viscosity range, giving the fire extinguishing agent both rapid coverage and long-lasting adhesion characteristics.

[0073] Through the above technical solution, this application can ensure that the extinguishing agent maintains a stable physical state during storage and use, avoiding problems such as spray blockage and incomplete coverage caused by slurry stratification or uneven mixing, thereby improving the suppression efficiency of power battery fires.

[0074] This application further proposes a method for using a fire extinguishing agent to quickly suppress fires in power batteries. The fire extinguishing agent is prepared by a specific method and is used as follows: the generated three-phase mixed fire extinguishing agent is sprayed onto the surface of the burning lithium-ion battery through an adjustable fan-shaped nozzle at a spray rate of 500-1000 g / min, and the coverage shape of the fire extinguishing agent is controlled by adjusting the fan-shaped nozzle.

[0075] The three-phase mixed extinguishing agent refers to a solid-liquid-gas three-phase mixed system formed by aerogel powder, water, and carbon dioxide gas through a static mixer. Specifically, a static mixer with an S-shaped turbulence unit can be used to achieve uniform dispersion of the substances. This mixing method can form a stable dispersion system in which gas and liquid encapsulate solid particles. The adjustable fan-shaped nozzle refers to a flat nozzle device with an adjustable spray angle. Specifically, a metal nozzle with a rotary adjustment mechanism can be used to adjust the angle, allowing the extinguishing agent coverage area to be changed according to the battery pack's spatial layout. The spray rate of 500-1000 g / min refers to the mass of extinguishing agent sprayed per unit time. Specifically, the flow rate can be controlled by adjusting the delivery pressure of the corrosion-resistant pump. This rate range can balance extinguishing efficiency and material consumption.

[0076] Specifically, when a lithium-ion battery experiences thermal runaway, a three-phase mixed extinguishing agent is delivered to a fan-shaped nozzle via a pressure-resistant pipeline. The flat spray pattern of the nozzle allows the extinguishing agent to form a thin layer covering the battery surface. Aerogel powder rapidly absorbs leaked electrolyte, and carbon dioxide gas expands and absorbs heat during spraying, isolating oxygen. By rotating the nozzle's adjustment ring, the spray angle can be adjusted to a 30° narrow-angle mode to penetrate the gaps between battery modules, or to a 90° wide-angle mode to cover a large area of ​​battery clusters. A low-speed spray of 500g / min is suitable for precise suppression of localized fires, while a high-speed spray of 1000g / min is suitable for suppressing large-area fires.

[0077] In some specific implementations, the nozzle angle adjustment mechanism can employ a worm gear transmission structure to achieve stepless positioning, and the injection flow control valve can be equipped with a digital flow sensor to achieve closed-loop control. The synergistic effect of aerogel powder and carbon dioxide can form a porous heat insulation layer, effectively blocking the heat radiation transfer path.

[0078] Compared to existing technologies, traditional fire extinguishing agent spraying often uses fixed-angle conical nozzles, which can easily create blind spots in complex battery pack structures, and high-speed spraying can lead to fire extinguishing agent splashing and waste. This solution achieves directional coverage through adjustable-angle fan-shaped nozzles, combined with a specific spray rate range, allowing the fire extinguishing agent to accurately adhere to the battery surface and form a continuous protective layer, avoiding the problem of low fire extinguishing agent utilization caused by improper spraying patterns in traditional technologies.

[0079] Through the above technical solution, this application can dynamically adjust the extinguishing agent coverage pattern according to the spatial structural characteristics of the power battery pack, forming a stable aerogel isolation layer while suppressing the spread of flames, effectively blocking oxygen supply and heat transfer paths. This method can quickly extinguish open flames and prevent the reignition of residual substances inside the battery through continuous coverage, while avoiding the accumulation of aerogel materials or excessive consumption of carbon dioxide caused by excessive spraying.

[0080] This application further proposes a method for using the extinguishing agent in which the spray angle of the fan-shaped nozzle is set to be infinitely adjustable within the range of 30° to 90°, so as to adapt to the directional coverage of lithium-ion battery packs with different layouts.

[0081] Among them, the fan-shaped nozzle refers to a fluid distribution device with a flat fan-shaped spray pattern. Specifically, it can be implemented using a metal alloy nozzle with a rotatable adjustment knob. Its internal flow channel is optimized to form a uniform fluid distribution. Stepless adjustment refers to a continuous change control method for the spray angle. Specifically, it can be achieved through a mechanical angle adjustment mechanism or an electric servo drive mechanism, without the need to preset a fixed gear during the adjustment process.

[0082] Specifically, when a fire breaks out inside a lithium-ion battery pack due to thermal runaway, the battery module arrangement varies across different vehicle models, including horizontal parallel, vertical stacking, or honeycomb layouts. By continuously adjusting the spray angle of the fan-shaped nozzles within the range of 30° to 90°, the coverage area formed by the extinguishing agent can be gradually expanded from a narrow strip to a wide fan shape. For example, for closely packed cylindrical cell modules, a smaller spray angle can create a high-impact linear jet that penetrates the gaps between the cells; for flat square cell modules, a larger spray angle creates a large-area coverage. This adjustment method allows a single set of nozzles to be matched with battery packs of different sizes, eliminating the need to replace the nozzle assembly.

[0083] Compared to existing technologies, traditional fire extinguishing devices often employ a fixed-angle spray method, which can easily create blind spots or excessive accumulation of extinguishing agent when dealing with complex battery pack structures. This solution, however, utilizes a stepless angle adjustment function to adjust the coverage pattern in real time according to the actual arrangement density of the battery modules, ensuring effective deposition of the extinguishing agent while avoiding material waste caused by excessive diffusion.

[0084] Through the above technical solution, this application can accurately match the structural characteristics of different power battery systems, ensure that the extinguishing agent quickly forms an effective covering layer in the early stage of thermal runaway, significantly reduce the risk of reignition caused by mismatched spray angles, and reduce the ineffective loss of extinguishing agent in complex space environments.

[0085] Example 1

[0086] This embodiment provides a fire extinguishing agent for rapidly suppressing fires in power batteries, the components and mass percentages of which are as follows:

[0087] Aerogel powder: 60%, in this embodiment, alumina aerogel powder with a specific surface area of ​​900 m² / g and a porosity of 95% is selected;

[0088] Water: 35%, deionized water preferred;

[0089] Functional additives: 5%, including 3% fluorocarbon surfactants and 2% lithium-ion battery-specific flame retardant, which is azobisisobutyrazoline hydrochloride.

[0090] Its preparation method is as follows:

[0091] S1: Add water to a premix tank equipped with a high-speed shear disperser according to the ratio. Add functional additives according to the ratio at a stirring speed of 300 rpm and stir for 10 minutes until they are completely dissolved.

[0092] S2: Increase the stirring speed to 3000 rpm and slowly add the aerogel powder in batches according to the ratio. The aerogel powder is added evenly at a rate of 1~2 kg / min.

[0093] S3: Continuously shear and disperse at high speed for 25 minutes until a homogeneous, viscous slurry without visible particles is formed, and then seal and store at 20°C for later use. The viscosity of the slurry is 10000 mPa·s.

[0094] S4: The slurry prepared in step S3 is pumped into the first inlet of a static mixer with a built-in S-type turbulence unit at a rate of 500 g / min using a plunger pump.

[0095] S5: High-pressure carbon dioxide gas with a pressure of 2 MPa and a temperature of 15°C is introduced into the second inlet of the static mixer;

[0096] S6: The slurry and high-pressure carbon dioxide gas are fully mixed in the static mixer to generate a three-phase mixed extinguishing agent, wherein the volume of carbon dioxide accounts for 50% of the volume of the mixture.

[0097] Fire extinguishing effect experiment

[0098] Experimental model: Nine fully charged lithium-ion battery cells from a certain brand of electric vehicle were laid out in a 3×3 grid on a table. The central battery cell was punctured by needle penetration, inducing thermal runaway and fire.

[0099] Experimental group: After the central battery explodes, the fire extinguishing agent of the present invention prepared above is immediately sprayed, with a total spray volume of 1 kg.

[0100] Comparative Example 1: A control group was set up. The extinguishing agent formulation in this group consisted of 60% alumina aerogel powder and 40% water, without the addition of functional additives. The preparation and spraying conditions of the extinguishing agent were as follows (CO2). 2 The pressure was 2 MPa and the spraying rate was 500 g / min, exactly the same as the experimental group.

[0101] Comparative Example 2: Another control group was set up. The fire extinguishing agent formulation of this group was 55% alumina aerogel powder, 35% water and 10% functional additives (of which flame retardant was 7%). The fire extinguishing agent preparation and spraying conditions were exactly the same as those of the experimental group.

[0102] Comparative Example 3 (blank control): Using pure water, 1 kg was sprayed at a rate of 500 g / min under a carbon dioxide drive of 2 MPa.

[0103] The experimental results are shown in Table 1:

[0104] Group Fire extinguishing effect Battery status reignition situation Example 1 The battery explosion was quickly contained. The flames went out, and there was no open flame. No reignition; the battery pack showed no smoke or explosion within 30 minutes of being left to stand. Comparative Example 1 The open flames were extinguished and the fire did not spread. The battery continued to smoke and then short-circuited and exploded. There is a risk of reignition; the insulation and chemical inhibition effects are insufficient. Comparative Example 2 The fire extinguishing effect was comparable to that of the experimental group. The flames went out, and there was no open flame. No reignition occurred, but the cost increased by approximately 20% compared to the experimental group. Comparative Example 3 Almost no inhibitory effect The battery explosion rapidly spread to the surrounding area. The fire was completely out of control.

[0105] Table 1

[0106] In summary, the composite fire extinguishing agent of Example 1 provided by this invention exhibits superior comprehensive performance. Specifically, this preferred fire extinguishing agent can rapidly interrupt battery deflagration, extinguishing open flames immediately after spraying. Furthermore, the treated batteries showed no reignition, smoke, or short-circuit explosion during a 30-minute observation period, demonstrating fundamental fire extinguishing and reignition prevention capabilities. Comparative analysis leads to the following conclusion: there is a synergistic effect between functional additives (especially flame retardants specifically for lithium-ion batteries), aerogel powder, and water. Comparative Example 1 (without functional additives) extinguished open flames but failed to inhibit internal electrochemical reactions, leading to eventual battery explosion. This demonstrates that functional additives are indispensable for chemically inhibiting thermal runaway chain reactions. While Comparative Example 2 (high content of functional additives) achieved similar fire extinguishing effects, its cost increased significantly, demonstrating that the preferred formulation of this invention achieves optimal economy while ensuring ultimate performance.

[0107] Ultimately, the experimental data fully support the following conclusion: This invention, through a gas-liquid-solid three-phase system, successfully achieves a highly efficient synergy of physical isolation (aerogel), cooling (water), and chemical inhibition (functional additives) triple fire extinguishing mechanisms, providing an efficient, safe, and cost-controllable preferred solution for solving the technical challenge of lithium-ion battery fires.

[0108] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A fire extinguishing agent for rapidly suppressing a fire of a power battery, characterized by, By mass percentage, comprising: Aerogel powder 40%~60%; Water 30%~40%; Functional additives 5%~15%; Wherein, the aerogel powder comprises at least one of silica aerogel, alumina aerogel and silica-alumina aerogel, the extinguishing agent uses carbon dioxide gas with a pressure of 1~5Mpa as an auxiliary injection gas and a premixed medium, and the carbon dioxide accounts for 40%~60% of the total volume of the mixed extinguishing agent.

2. The extinguishing agent for quickly suppressing the fire of a power battery according to claim 1, characterized in that: The functional additives comprise at least one of a surfactant and a lithium-ion battery flame retardant.

3. The extinguishing agent for quickly suppressing the fire of a power battery according to claim 2, characterized in that: The lithium-ion battery flame retardant is azobisimidozoline hydrochloride.

4. The extinguishing agent for quickly suppressing the fire of a power battery according to claim 2, characterized in that: The surfactant comprises a fluorocarbon surfactant.

5. The extinguishing agent for quickly suppressing the fire of a power battery according to claim 1, characterized in that: The aerogel powder has a porosity of not less than 90%, and a specific surface area of 800-1000 m 2 / g.

6. The preparation method of the fire extinguishing agent for quickly suppressing the fire of power batteries according to any one of claims 1-5, characterized in that, Comprising the following steps: S1: water is added into a premixing tank with a high-speed shearing disperser in proportion, functional additives are added in proportion under a stirring speed of 200~400rpm, and stirring is performed for 5~10min until the functional additives are completely dissolved; S2: the stirring speed is increased to 2000~5000rpm, and aerogel powder is slowly and batchwise added in proportion; S3: high-speed shearing dispersion is continuously performed for 20~30min until a homogeneous and non-granular viscous slurry is formed, and the slurry is stored for standby use under a 15~25℃ environment; S4: the slurry prepared in step S3 is pumped into a first inlet of a static mixer with an embedded S-shaped turbulent unit through a corrosion-resistant pump; S5: high-pressure carbon dioxide gas with a pressure of 1~5Mpa and a temperature of 10~20℃ is introduced into a second inlet of the static mixer; S6: the slurry and the high-pressure carbon dioxide gas are fully mixed in the static mixer to generate a three-phase mixed extinguishing agent.

7. The preparation method of the extinguishing agent for quickly suppressing the fire of a power battery according to claim 6, characterized in that: In step S2, the aerogel powder is uniformly added at a rate of 1~2kg / min.

8. The preparation method of the extinguishing agent for quickly suppressing the fire of a power battery according to claim 6, characterized in that: In step S3, the viscosity of the slurry is 5000~15000mPa·s.

9. A method for using a fire extinguishing agent for quickly suppressing a fire of a power battery, characterized in that, The extinguishing agent prepared by the preparation method of claim 6 is used as follows: The generated three-phase mixed extinguishing agent is sprayed onto the surface of the on-fire lithium-ion battery through an adjustable fan-shaped nozzle at a spraying rate of 500~1000g / min, and the covering shape of the extinguishing agent is controlled by adjusting the fan-shaped nozzle.

10. The use method of the extinguishing agent for quickly suppressing the fire of a power battery according to claim 9, characterized in that: The spray angle of the fan-shaped nozzle is set in the range of 30°-90° for stepless adjustment to adapt to directional covering of lithium ion battery packs with different layouts.