Lithium ion battery sol-gel fire extinguishing agent and preparation method thereof

Abstract

The invention relates to the technical field of fire extinguishing agents special for lithium ion batteries, in particular to a sol-gel fire extinguishing agent for lithium ion batteries and a preparation method of the sol-gel fire extinguishing agent, and the sol-gel fire extinguishing agent is formed by taking silica gel as a framework and inclusion of melamine-formaldehyde resin and urea-diammonium hydrogen phosphate microcapsules in the framework. The preparation method comprises the following steps: S1, synthesizing a melamine-formaldehyde resin prepolymer; step S2, synthesis of a melamine-formaldehyde resin coated urea-diammonium hydrogen phosphate microcapsule; and S3, synthesizing the sol-gel fire extinguishing agent for the lithium ion battery. The sol-gel fire extinguishing agent prepared through the method is stable at the normal temperature, the fire extinguishing agent rapidly absorbs heat and cools the temperature at the high temperature, the fire extinguishing agent is decomposed to release a large amount of smoke composed of water vapor, ammonia gas, CO2, SiO2 aerogel and the like, a polyphosphoric acid diaphragm is generated, the oxygen concentration in air is reduced, an isolation layer for air mass transfer and heat transfer is formed, and the fire extinguishing effect is improved. And the efficient and rapid fire extinguishing effect on the lithium ion battery is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery special fire extinguishing agent, in particular to a lithium ion battery sol-gel fire extinguishing agent and a preparation method thereof. Background Art

[0002] Lithium batteries are widely used in electric vehicles, energy storage power stations and other fields due to their high energy density, long life cycle, low self-discharge rate and no memory. However, due to the complex and diverse operating environment and abuse, such as battery extrusion and puncture caused by collision, overcharging and over-discharging, high-temperature spontaneous combustion, water ingress into the battery, and impurities introduced into the battery during the manufacturing process, it is very easy to cause thermal runaway of lithium batteries, which in turn leads to the release of toxic gases, large amounts of heat and even explosions and fires, resulting in casualties and property losses. It is crucial to effectively extinguish lithium battery fires.

[0003] In lithium battery fires, the fire extinguishing agents currently used more often include solid fire extinguishing agents such as dry powder fire extinguishing agents and aerosol fire extinguishing agents, gas fire extinguishing agents such as CO2, heptafluoropropane, perfluorohexanone, etc., and liquid water-based fire extinguishing agents such as water, fine water mist, and fine water mist additives. Dry powder fire extinguishing agents can extinguish external open flames under appropriate conditions, but their cooling effect only exists in the part that contacts the battery, and the effect is very limited. After the fire extinguishing agent is stopped, the battery temperature rises rapidly, and there is a very high risk of re-ignition. Aerosol fire extinguishing agents can quickly extinguish open flames, but they cannot suppress the spread of thermal runaway in the module. The continuous release of a large amount of smoke causes heat to accumulate rapidly in a limited space, causing the battery module to quickly reignite. CO2 fire extinguishing agents can extinguish external open flames of lithium batteries by isolating oxygen, but their heat capacity is very low, and it is difficult to reduce the battery temperature. They cannot suppress the chain decomposition reaction inside the battery and the spread of thermal runaway in the battery module, and the battery is still in a dangerous state. Heptafluoropropane fire extinguishing agent shows better fire extinguishing effect than CO2 fire extinguishing agent, but the cooling effect of heptafluoropropane fire extinguishing agent is not significant. Although large-scale use can improve the cooling effect, excessive use will produce a large amount of HF, which will cause damage to human body and equipment. Water can solve the problem to a certain extent due to its good cooling effect, but once the water spraying stops, the battery will reignite, and because water is conductive, the battery pack sprayed with water is not suitable for secondary use. No new lithium-ion battery sol-gel fire extinguishing agent has been reported. The development of a sol-gel fire extinguishing agent with high efficiency and rapid fire extinguishing is of great significance to the development and application of lithium-ion batteries. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a lithium ion battery sol-gel fire extinguishing agent and a preparation method thereof. The prepared lithium ion battery sol-gel fire extinguishing agent can quickly absorb heat to reduce the surface temperature of the lithium ion battery, while diluting the oxygen concentration in the air, isolating the diffusion and mass transfer of oxygen and heat in the air, and has an efficient and rapid fire extinguishing effect on the lithium ion battery.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A lithium-ion battery sol-gel fire extinguishing agent comprises a silica gel skeleton and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton.

[0007] The present invention also provides a method for preparing a lithium ion battery sol-gel fire extinguishing agent, the preparation method comprising the following steps:

[0008] Step S1: Synthesis of melamine-formaldehyde resin prepolymer

[0009] Weigh a certain amount of melamine, stir and dissolve it in deionized water at 50°C, then drop a certain amount of formaldehyde, and under stirring, drop a certain amount of triethanolamine, adjust the pH value to 10, stir and dissolve for 1 hour, and after hydroxymethyl melamine is formed, adjust the pH value to 6 with HAc, continue stirring for 3-5 hours, and form a transparent melamine-formaldehyde resin prepolymer solution;

[0010] Step S2: Synthesis of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules

[0011] Weigh a certain amount of urea and diammonium hydrogen phosphate, add them to a certain amount of melamine-formaldehyde resin prepolymer solution, stir to dissolve, add HAc dropwise, and adjust the pH value of the system to 4-4.5 under stirring, so that the melamine-formaldehyde resin prepolymer is polycondensed to form melamine-formaldehyde resin coating on urea, and vacuum dry at 50° C. to obtain melamine-formaldehyde resin@urea-diammonium hydrogen phosphate microcapsules;

[0012] Step S3: Synthesis of Lithium Ion Battery Sol-Gel Fire Extinguishing Agent

[0013] Weigh a certain amount of Na2SiO3·9H2O, heat and dissolve it or dissolve it with a certain amount of deionized water, then add a certain amount of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules under stirring, and drop a certain amount of 4 mol / L H2SO4 solution. Na2SiO3·9H2O reacts with H2SO4 to generate silica sol, and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules are evenly dispersed in the silica sol. Continue stirring to obtain a semi-solid lithium ion battery sol-gel fire extinguishing agent with silica gel as the skeleton and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton.

[0014] Preferably, in step S1, the molar ratio of melamine to formaldehyde is 1:(3-6).

[0015] Preferably, in step S2, the mass ratio of melamine-formaldehyde resin to urea is 1:9.

[0016] Preferably, in step S2, the mass ratio of urea to diammonium hydrogen phosphate in the melamine-formaldehyde resin@urea-diammonium hydrogen phosphate microcapsules is 0.8-1.2:1.

[0017] Preferably, in step S3, the mass ratio of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules in the lithium-ion battery sol-gel fire extinguishing agent is 20-40%.

[0018] Preferably, in step S3, the mass ratio of deionized water in the lithium-ion battery sol-gel fire extinguishing agent is 40-60%.

[0019] Preferably, in step S3, the mass ratio of silica gel in the lithium-ion battery sol-gel fire extinguishing agent is 8-12%.

[0020] By adopting the above technical scheme: the lithium ion battery sol-gel fire extinguishing agent prepared by the method has a strong inhibitory effect on lithium ion battery fires. When extinguishing a fire, the water in the sol-gel evaporates and absorbs heat to greatly reduce the temperature, and at the same time generates a large amount of water vapor. While the microcapsules absorb a large amount of heat to reduce the temperature, urea and diammonium hydrogen phosphate decompose to form inert gases such as N2, NH3, CO2, etc., and diammonium hydrogen phosphate also generates viscous polyphosphoric acid. Water vapor and inert gases such as N2, NH3, CO2 dilute the concentration of oxygen in the air. The viscous polyphosphoric acid film and CO2 cover the battery surface to form a good gas-solid isolation to isolate the diffusion and mass transfer of air and external heat to the lithium ion battery and the heat conduction between adjacent batteries. After the water in the sol-gel evaporates, a foamy porous SiO2 aerogel is formed, which also has good thermal insulation. These synergistic effects enable it to quickly absorb heat to reduce the surface temperature of the lithium ion battery, while diluting the oxygen concentration in the air, isolating the diffusion and mass transfer of oxygen and heat in the air, and having an efficient and rapid fire extinguishing effect on the lithium ion battery.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention forms a semi-solid lithium ion battery sol-gel fire extinguishing agent with silica gel as the skeleton and melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton. The fire extinguishing agent is relatively stable at room temperature. Only at a higher temperature will diamine hydrogen phosphate and urea in the fire extinguishing agent decompose and release water vapor, ammonia, CO2, etc., which has an efficient and rapid fire extinguishing effect on lithium ion batteries.

[0023] 2. When the present invention extinguishes a fire, a large amount of water in the sol-gel fire extinguishing agent absorbs heat and evaporates, which greatly reduces the surface temperature of the lithium-ion battery and generates a large amount of inert water vapor and foamy porous SiO2 aerogel. A large amount of water vapor can greatly reduce the oxygen concentration in the air. The porous SiO2 aerogel has good thermal insulation properties, which can isolate the heat from diffusing and transferring to other parts of the lithium-ion battery or other batteries.

[0024] 3. The microcapsules in the present invention absorb a large amount of heat and decompose to lower the temperature. At the same time, urea and diammonium hydrogen phosphate decompose to form inert gases such as N2, NH3, CO2, etc., and diammonium hydrogen phosphate also generates viscous polyphosphoric acid. Water vapor and inert gases such as N2, NH3, CO2 dilute the concentration of oxygen in the air. The viscous polyphosphoric acid film and CO2 cover the surface of the battery to form a good gas-solid isolation to isolate the air, isolate the heat from the diffusion and mass transfer to other parts of the lithium-ion battery, and the heat conduction between adjacent batteries.

[0025] 4. The sol-gel fire extinguishing agent of the present invention does not contain halogen when extinguishing fire. The synergistic effect of various components has a high-efficiency and rapid fire extinguishing effect on lithium-ion batteries while causing no damage to people and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a photo of a battery puncture process coated with a sol-gel fire extinguishing agent in an embodiment of the present invention;

[0027] Figure 2 These are comparison photos of a battery coated with a sol-gel fire extinguishing agent before and after being punctured in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] (1) Synthesis of melamine-formaldehyde resin prepolymer

[0031] Weigh 10g of melamine, stir and dissolve in 50mL of deionized water at 50℃, then add 18.5mL of 37% formaldehyde, add a certain amount of triethanolamine while stirring, adjust the pH value to 10, stir and dissolve for 1h, after hydroxymethyl melamine is formed, adjust the pH value to 6 with HAc, continue stirring for 3-5h to form a transparent melamine-formaldehyde resin prepolymer solution.

[0032] (2) Synthesis of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules

[0033] Weigh 70.2g of urea and 70.2g of diamine hydrogen phosphate and add them to 15.6g of the melamine-formaldehyde resin prepolymer solution prepared in step (1), stir to dissolve, add HAc dropwise, and adjust the pH value of the system to 4-4.5 under stirring, so that the melamine-formaldehyde resin prepolymer is polycondensed to form melamine-formaldehyde resin coating the urea. Vacuum dry at 50°C to obtain melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules with a mass ratio of melamine-formaldehyde resin to urea-diamine hydrogen phosphate of 1:9 and a mass ratio of urea to diamine hydrogen phosphate of 1:1.

[0034] (3) Synthesis of Lithium-ion Battery Sol-Gel Fire Extinguishing Agent

[0035] Weigh 40 g of Na2SiO3·9H2O, dissolve it in 8 g of deionized water, add 32 g of the melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules prepared in step (2) under stirring, add 40 mL of 4 mol / L H2SO4 solution dropwise, react sodium silicate with H2SO4 to form silica sol, uniformly disperse the melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules in the silica sol, continue stirring, and obtain a semi-solid lithium ion battery sol-gel fire extinguishing agent with silica gel as the skeleton and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton, wherein the mass fraction of silica gel in the fire extinguishing agent is 8%, the mass fraction of water is 53.5%, and the mass fraction of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules is 25.2%.

[0036] Example 2

[0037] (1) Synthesis of melamine-formaldehyde resin prepolymer

[0038] Weigh 10g of melamine, stir and dissolve in 50mL of deionized water at 50℃, then add 18.5mL of 37% formaldehyde, add a certain amount of triethanolamine while stirring, adjust the pH value to 10, stir and dissolve for 1h, after hydroxymethyl melamine is formed, adjust the pH value to 6 with HAc, continue stirring for 3-5h to form a transparent melamine-formaldehyde resin prepolymer solution.

[0039] (2) Synthesis of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules

[0040] Weigh 70.2g of urea and 70.2g of diamine hydrogen phosphate and add them to 15.6g of the melamine-formaldehyde resin prepolymer solution prepared in step (1), stir to dissolve, add HAc dropwise, and adjust the pH value of the system to 4-4.5 under stirring, so that the melamine-formaldehyde resin prepolymer is polycondensed to form melamine-formaldehyde resin coating the urea. Vacuum dry at 50°C to obtain melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules with a mass ratio of melamine-formaldehyde resin to urea-diamine hydrogen phosphate of 1:9 and a mass ratio of urea to diamine hydrogen phosphate of 1:1.

[0041] (3) Synthesis of Lithium-ion Battery Sol-Gel Fire Extinguishing Agent

[0042] Weigh 40 g of Na2SiO3·9H2O, heat to 50 degrees to dissolve, add 40 g of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules prepared in step (2) under stirring after dissolution, add 40 mL of 4 mol / L H2SO4 solution dropwise, react sodium silicate with H2SO4 to form silica sol, uniformly disperse the melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules in the silica sol, continue stirring, and obtain a semi-solid lithium ion battery sol-gel fire extinguishing agent with silica gel as the skeleton and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton, wherein the mass fraction of silica gel in the fire extinguishing agent is 8%, the mass fraction of water is 55.2%, and the mass fraction of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules is 28.3%.

[0043] Example 3

[0044] (1) Synthesis of melamine-formaldehyde resin prepolymer

[0045] Weigh 10g of melamine, stir and dissolve in 50mL of deionized water at 50℃, then add 18.5mL of 37% formaldehyde, add a certain amount of triethanolamine while stirring, adjust the pH value to 10, stir and dissolve for 1h, after hydroxymethyl melamine is formed, adjust the pH value to 6 with HAc, continue stirring for 3-5h to form a transparent melamine-formaldehyde resin prepolymer solution.

[0046] (2) Synthesis of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules

[0047] Weigh 62.4g of urea and 78.0g of diamine hydrogen phosphate and add them to 15.6g of the melamine-formaldehyde resin prepolymer solution prepared in step (1), stir to dissolve, add HAc dropwise, and adjust the pH value of the system to 4-4.5 under stirring, so that the melamine-formaldehyde resin prepolymer is polycondensed to form melamine-formaldehyde resin coating the urea. Vacuum dry at 50°C to obtain melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules with a mass ratio of melamine-formaldehyde resin to urea-diamine hydrogen phosphate of 1:9 and a mass ratio of urea to diamine hydrogen phosphate of 0.8:1.

[0048] (3) Synthesis of Lithium-ion Battery Sol-Gel Fire Extinguishing Agent

[0049] Weigh 40g of Na2SiO 3· 9H2O, heated to 50 degrees to dissolve, after dissolution, 36.4g of melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules prepared in step (2) were added under stirring, 21.8mL of 4mol / L H2SO4 solution was added dropwise, sodium silicate reacted with H2SO4 to form silica sol, melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules were uniformly dispersed in the silica sol, and stirring was continued to obtain a semi-solid lithium ion battery sol-gel fire extinguishing agent with silica gel as the skeleton and melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton, wherein the mass fraction of silica gel in the fire extinguishing agent was 10%, the mass fraction of water was 42.2%, and the mass fraction of melamine-formaldehyde resin @ urea-diamine hydrogen phosphate microcapsules was 35.6%.

[0050] Fire extinguishing performance test:

[0051] The fire extinguishing performance test of the sol-gel fire extinguishing agent was carried out in the blue battery charge and discharge test system and the needle puncture extrusion integrated machine. First, the ternary lithium battery to be tested was charged to a full charge state with a current of 1C, and then the fire extinguishing agent prepared in Example 1 was evenly coated on the surface and edge of the battery to be tested, with a thickness of about 5mm. A steel needle with a diameter of 6mm was selected, and the steel needle angle was 45-60° at the center of the battery at a speed of 25mm / s perpendicular to the battery surface, and then maintained for 10 minutes.

[0052] The fire extinguishing performance test results showed that the lithium battery not coated with sol-gel fire extinguishing agent quickly heated up and produced a fire after being punctured by a steel needle, while the lithium battery coated with sol-gel fire extinguishing agent quickly generated thick smoke without producing open flames.

[0053] Figure 1 This is a photo of the puncture process of a lithium battery coated with a fire extinguishing agent. Figure 1It can be seen that the battery coated with sol-gel fire extinguishing agent emits thick smoke during the puncture process, and no open flame occurs. This shows that during the puncture process, the battery releases heat rapidly, quickly generates high temperature, and causes the battery to catch fire. However, under the action of the sol-gel fire extinguishing agent, the various components of the fire extinguishing agent play a synergistic role, causing the battery surface temperature to drop rapidly. The fire extinguishing agent decomposes and releases a large amount of smoke composed of water vapor, ammonia, CO2, and SiO2 aerogel produced after water decomposition, which reduces the oxygen concentration in the air and forms an insulating layer for air mass transfer and heat transfer, so that the battery fire is quickly extinguished without generating open flames or re-ignition.

[0054] Figure 2 Comparison photos of lithium batteries coated with fire extinguishing agent before and after needle puncture. As can be seen from the picture, the fire extinguishing agent has a good fire extinguishing effect. The fire extinguishing agent near the battery fire point plays a good fire extinguishing role. The fire extinguishing agent forms a diaphragm on the surface of the fire point. The heat generated by the rapid heating of the battery without fire diffuses and transfers to the surrounding area.

[0055] Figure 1 , Figure 2 The results show that the sol-gel fire extinguishing agent has a high efficiency and rapid fire extinguishing effect on lithium-ion batteries.

[0056] In summary, the lithium ion battery sol-gel fire extinguishing agent prepared by the present invention can quickly absorb heat to reduce the surface temperature of the lithium ion battery, while diluting the oxygen concentration in the air, isolating the diffusion mass transfer of oxygen and heat in the air, and has an efficient and rapid fire extinguishing effect on lithium ion batteries.

[0057] The description and practice disclosed in the present invention are easy to think and understand for ordinary technicians in the technical field, and several improvements and modifications can be made without departing from the principles of the present invention. Therefore, modifications or improvements made without departing from the spirit of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A lithium ion battery sol-gel fire extinguishing agent, characterized in that: The lithium-ion battery sol-gel fire extinguishing agent is formed by using silica gel as a skeleton, and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules are encapsulated in the skeleton.

2. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 1, characterized in that: The preparation method comprises the following steps: Step S1: Synthesis of melamine-formaldehyde resin prepolymer Weigh a certain amount of melamine, stir and dissolve it in deionized water at 50°C, then drop a certain amount of formaldehyde, and under stirring, drop a certain amount of triethanolamine, adjust the pH value to 10, stir and dissolve for 1 hour, and after hydroxymethyl melamine is formed, adjust the pH value to 6 with HAc, continue stirring for 3-5 hours, and form a transparent melamine-formaldehyde resin prepolymer solution; Step S2: Synthesis of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules Weigh a certain amount of urea and diammonium hydrogen phosphate, add them to a certain amount of melamine-formaldehyde resin prepolymer solution, stir to dissolve, add HAc dropwise, and adjust the pH value of the system to 4-4.5 under stirring, so that the melamine-formaldehyde resin prepolymer is polycondensed to form melamine-formaldehyde resin coating on urea, and vacuum dry at 50° C. to obtain melamine-formaldehyde resin@urea-diammonium hydrogen phosphate microcapsules; Step S3: Synthesis of Lithium Ion Battery Sol-Gel Fire Extinguishing Agent Weigh a certain amount of Na2SiO3·9H2O, heat and dissolve it or dissolve it with a certain amount of deionized water, then add a certain amount of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules under stirring, and drop a certain amount of 4 mol / L H2SO4 solution. Na2SiO3·9H2O reacts with H2SO4 to generate silica sol, and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules are evenly dispersed in the silica sol. Continue stirring to obtain a semi-solid lithium ion battery sol-gel fire extinguishing agent with silica gel as the skeleton and melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules encapsulated in the skeleton.

3. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 2, characterized in that: In step S1, the molar ratio of melamine to formaldehyde is 1:(3-6).

4. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 2, characterized in that: In step S2, the mass ratio of melamine-formaldehyde resin to urea is 1:

9.

5. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 2, characterized in that: In step S2, the mass ratio of urea to diammonium hydrogen phosphate in the melamine-formaldehyde resin@urea-diammonium hydrogen phosphate microcapsules is 0.8-1.2:

1.

6. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 2, characterized in that: In step S3, the mass ratio of melamine-formaldehyde resin@urea-diamine hydrogen phosphate microcapsules in the lithium-ion battery sol-gel fire extinguishing agent is 20-40%.

7. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 2, characterized in that: In step S3, the mass ratio of deionized water in the lithium-ion battery sol-gel fire extinguishing agent is 40-60%.

8. The method for preparing a lithium ion battery sol-gel fire extinguishing agent according to claim 2, characterized in that: In step S3, the mass ratio of silica gel in the lithium-ion battery sol-gel fire extinguishing agent is 8-12%.

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