Temperature-sensitive hydrogel additive, preparation method thereof and hydrogel fire extinguishing agent

Abstract

The invention provides a temperature-sensitive hydrogel additive, a preparation method thereof and a hydrogel fire extinguishing agent. The temperature-sensitive hydrogel fire extinguishing additive comprises the following raw materials: a temperature-sensitive substance, a thickening agent, a cross-linking monomer, an initiator and a cross-linking agent in a mass ratio of (0.3-1.7): (0.2-0.9): (2-10): (0.1-0.3): (0.01-0.05), the temperature-sensitive substance is methyl cellulose and / or carboxymethyl cellulose, the thickening agent is carboxymethyl chitosan and / or chitosan, and the cross-linking monomer is acrylic acid. The temperature-sensitive type hydrogel fire extinguishing agent additive for the lithium battery fire disasters solves the problems that an existing fire extinguishing agent is weak in cooling capacity, low in fire extinguishing efficiency, poor in adhesiveness, high in reburning rate, not environmentally friendly in material and the like when coping with the lithium battery fire disasters, and can rapidly release water to absorb heat and cool under the high-temperature condition; meanwhile, a compact closed film layer is formed on the surface of the battery to isolate oxygen from being in contact with electrolyte, so that reburning is effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of lithium battery fire extinguishing agent technology, and in particular to a temperature-sensitive hydrogel additive, its preparation method, and a hydrogel fire extinguishing agent. Background Technology

[0002] With the rapid development of electric vehicles, energy storage systems, and consumer electronics, lithium-ion batteries are widely used due to their high energy density. However, they are highly susceptible to violent combustion, explosion, and even reignition under thermal runaway conditions, posing a serious threat to personnel and equipment safety. While commonly used fire extinguishing agents such as dry powder, carbon dioxide, water mist, and foam are effective in ordinary fires, they often suffer from low extinguishing efficiency, incomplete cooling, difficulty in adhesion, secondary pollution, or high reignition rates when dealing with the complex internal structure of lithium batteries, high-temperature heat release, and electrolyte spraying characteristics.

[0003] While hydrogel-based fire extinguishing materials have emerged in recent years and possess certain temperature-sensitive response and heat-absorbing properties—for example, inventions CN110404225B, CN108553788A, and CN115869578B propose temperature-sensitive gel foams or fine water mist additives for Class A or Class B fires—they often suffer from problems such as excessive viscosity, difficulty in spraying, insufficient flame retardancy, or poor high-temperature stability. Furthermore, their raw material composition is complex, and some are even toxic, making them unsuitable for electrical equipment or lithium battery environments. In addition, some have attempted to improve fire extinguishing performance using new materials such as phase change materials, fluorinated flame retardants, or polymer foams, but these still face challenges due to complex material sourcing or high manufacturing costs, hindering large-scale promotion.

[0004] Therefore, there is an urgent need to develop an environmentally friendly, safe, rapidly thermally responsive, highly adhesive hydrogel fire extinguishing material that can adapt to the characteristics of lithium battery fires, in order to solve the core problems of existing technologies such as the inability to completely extinguish fires and prevent reignition. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a temperature-sensitive hydrogel additive, its preparation method, and a hydrogel fire extinguishing agent. The temperature-sensitive hydrogel fire extinguishing agent additive and hydrogel fire extinguishing agent provided by this invention for lithium battery fires can solve the problems of weak cooling capacity, low extinguishing efficiency, poor adhesion, high reignition rate, and environmentally unfriendly materials in existing fire extinguishing agents when dealing with lithium-ion battery fires. Under high-temperature conditions, it can rapidly release water to absorb heat and cool, while simultaneously forming a tightly sealed film layer on the battery surface, isolating oxygen from contact with the electrolyte and effectively preventing reignition.

[0006] In a first aspect, this invention provides a temperature-sensitive hydrogel fire extinguishing additive, comprising a temperature-sensitive substance, a thickener, a crosslinking monomer, an initiator, and a crosslinking agent in a mass ratio of 0.3~1.7:0.2~0.9:2~10:0.1~0.3:0.01~0.05. The temperature-sensitive substance is methylcellulose and / or carboxymethylcellulose, the thickener is carboxymethyl chitosan and / or chitosan, and the crosslinking monomer is acrylic acid. This invention provides a temperature-sensitive hydrogel fire extinguishing agent additive for lithium battery fires, effectively solving the problems of weak cooling capacity, low extinguishing efficiency, poor adhesion, high reignition rate, and environmentally unfriendly materials in existing fire extinguishing agents for lithium-ion battery fires. Under high-temperature conditions, this hydrogel fire extinguishing agent can rapidly release water for heat absorption and cooling, while simultaneously forming a dense, sealed film layer on the battery surface, effectively isolating oxygen from contact with the electrolyte, thereby preventing reignition. This invention employs a certain proportion of temperature-sensitive materials (methylcellulose and / or carboxymethylcellulose), thickeners (carboxymethyl chitosan and / or chitosan), crosslinking monomers (acrylic acid), initiators, and crosslinking agents. Through the interaction of these raw materials, a three-dimensional network structure with high heat absorption, good adhesion, controllable film formation, and environmental friendliness is formed, which can significantly improve the fire extinguishing effect. It is especially suitable for rapid response and on-site containment of thermal runaway fires in lithium battery modules.

[0007] Preferably, the material comprises the following raw materials by weight: 0.5-1.5 parts of a temperature-sensitive substance, 0.2-0.8 parts of a thickener, 2-5 parts of a crosslinking monomer, 0.1-0.2 parts of an initiator, and 0.01-0.05 parts of a crosslinking agent. In this invention, the biodegradable and environmentally friendly temperature-sensitive matrix, thickener, and crosslinking monomer work synergistically to construct a multifunctional fire extinguishing gel system that combines thermal responsiveness, excellent film-forming properties, and flame-retardant sealing. This material is suitable for various application scenarios such as spraying, film application, and sealing, and is applicable to fire emergency response in lithium battery applications such as energy storage, electric vehicles, and transportation. It has comprehensive advantages such as simple structure, safe use, and environmental friendliness.

[0008] Further preferred formulations include the following raw materials in parts by weight: 0.8-1 parts of a temperature-sensitive substance, 0.4-0.5 parts of a thickener, 3-3.5 parts of acrylic acid, 0.1-0.2 parts of an initiator, and 0.01-0.02 parts of a crosslinking agent. The temperature-sensitive substance is methylcellulose or carboxymethylcellulose, more preferably methylcellulose. The thickener is carboxymethyl chitosan or chitosan, more preferably carboxymethyl chitosan. The preferred formulation of the above raw materials yields better results.

[0009] More preferably, the crosslinking agent is N,N'-methylenebis(acrylamide) and / or polyethylene glycol diacrylate, preferably N,N'-methylenebis(acrylamide).

[0010] More preferably, the initiator is ammonium persulfate (APS) and / or azobisisobutyronitrile (AIBN), with ammonium persulfate being more preferred.

[0011] This invention optimizes raw materials and proportions, and the synergistic effect of each component results in a temperature-sensitive hydrogel additive for suppressing lithium battery fires. This additive enhances the hydrogel fire extinguishing agent's temperature-sensitive response, heat absorption and cooling performance, and film-forming and sealing capabilities. It enables the hydrogel to gel rapidly, cool down, and prevent reignition in lithium battery thermal runaway fire scenarios, providing a more efficient and safer emergency protection method for electric vehicles, energy storage systems, and other applications.

[0012] Preferably, an appropriate amount of water is also included. The present invention does not limit the amount of water used. Preferably, the ratio of the temperature-sensitive substance to water is 1:60~100mL, for example, 1:60mL, 1:70mL, 1:80mL, 1:100mL, etc.

[0013] Preferably, an appropriate amount of pH adjuster is also included. The present invention does not limit the type and amount of pH adjuster. By adding a pH adjuster to acrylic acid, the pH of acrylic acid is made to be about 7.0. For example, 0.4~0.5 mol / L sodium hydroxide solution is added, and the ratio of acrylic acid to sodium hydroxide solution is 3~6g:0.5~1mL.

[0014] Secondly, the preparation method of the temperature-sensitive hydrogel fire extinguishing additive provided by the present invention includes the following steps: 1) Mix dried methylcellulose, carboxymethyl chitosan and crosslinking agent to obtain a mixed powder.

[0015] 2) Add the mixed powder to deionized water, heat and stir to obtain solution A.

[0016] 3) Adjust the pH of the acrylic acid to obtain solution B.

[0017] 4) Mix the solutions A and B and stir to obtain a mixed solution C.

[0018] 5) Mix the mixed solution C and the initiator and react them to obtain a thermosensitive hydrogel.

[0019] 6) The thermosensitive hydrogel is dried and then pulverized.

[0020] Preferably, in step 2), the heating is performed in a water bath at 55~65℃, and the stirring time is 1~2 hours.

[0021] Preferably, in step 3), the pH is adjusted to 6.5-7.5 using sodium hydroxide solution.

[0022] Preferably, in step 4), the stirring time is 20-40 minutes.

[0023] Preferably, in step 5), the reaction temperature is 55~65℃ and the reaction time is 30~60min.

[0024] Preferably, in step 6), the thermosensitive hydrogel is dried at 70~90℃ for 12~24h to obtain a solid gel block; the thermosensitive hydrogel is pulverized and passed through a 90~100 mesh sieve.

[0025] Thirdly, the present invention provides a hydrogel fire extinguishing agent, comprising the above-mentioned temperature-sensitive hydrogel fire extinguishing additive or the temperature-sensitive hydrogel fire extinguishing additive obtained by the above preparation method.

[0026] Preferably, in the hydrogel fire extinguishing agent, the mass fraction of the temperature-sensitive hydrogel fire extinguishing additive is 3% to 6%.

[0027] Further preferred, the temperature-sensitive hydrogel fire extinguishing additive is added to deionized water and stirred evenly to obtain a hydrogel fire extinguishing agent with a mass fraction of 3% to 6%. In this invention, the powdered temperature-sensitive hydrogel fire extinguishing additive is added to deionized water according to the mass fraction and stirred evenly. A stable hydrogel fire extinguishing agent can be formed under room temperature conditions for use in fire extinguishing devices. Using a preferred amount of temperature-sensitive hydrogel fire extinguishing additive mixed with deionized water yields better results.

[0028] Fourthly, the present invention also provides the application of the hydrogel fire extinguishing agent in extinguishing lithium battery fires.

[0029] The beneficial effects of this invention are at least as follows: The temperature-sensitive hydrogel fire extinguishing additive provided by this invention can achieve rapid response in high-temperature environments of lithium-ion battery fires, gelling and forming a dense covering film that effectively blocks oxygen and rapidly absorbs heat and cools the battery. This gel has excellent adhesion and structural stability, and can continuously act on the battery surface to prevent reignition. Experimental results show that this gel fire extinguishing agent can extinguish lithium battery flames within seconds and rapidly reduce the battery surface temperature. Furthermore, this additive is composed of temperature-sensitive substances, thickeners, acrylic acid, and other degradable or low-toxic components, exhibiting good environmental adaptability and safety in use. Its preparation process is simple, and it can be processed into powder or liquid form, suitable for portable spraying or embedded protection. It is particularly suitable for fire risk scenarios such as electric vehicles, energy storage systems, and lithium battery transportation and storage, and has broad engineering application prospects and promotional value. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 The infrared spectrum of the temperature-sensitive hydrogel fire extinguishing additive and some of its raw materials in Example 1 of this invention is shown.

[0032] Figure 2 EDS image of the MPC hydrogel provided in Example 2 of the present invention.

[0033] Figure 3 This is a schematic diagram of the cooling results in Examples 1-3 of the present invention.

[0034] Figure 4 This is a schematic diagram of the fire extinguishing results in Examples 1-3 of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0037] Unless otherwise specified, the reagents, materials and instruments used in the embodiments and comparative examples of this invention are all conventional reagents, materials and instruments that can be purchased. The reagents involved can also be obtained by purchasing or by synthesizing them using conventional synthesis methods.

[0038] Example 1 The raw materials of the thermosensitive hydrogel fire extinguishing additive provided in this embodiment, by weight, include: 1 part thermosensitive substance, 0.5 parts thickener, 3 parts acrylic acid, 0.2 parts initiator, and 0.01 parts crosslinking agent. The thermosensitive substance is methylcellulose, the thickener is carboxymethyl chitosan, the crosslinking agent is N,N'-methylenebis(acrylamide), and the initiator is ammonium persulfate (APS). The specific steps are as follows: 1. Place methylcellulose, carboxymethyl chitosan and N,N'-methylenebisacrylamide in a vacuum drying oven at 60°C and dry for 6 hours to remove moisture. Then weigh and mix them according to the proportion to obtain mixed powder A.

[0039] 2. Slowly add the mixed powder A to 80 mL of deionized water, place it in a three-necked flask, and stir for 1.5 h in a water bath at 60 °C to obtain a high-viscosity transparent solution A.

[0040] 3. In another container, mix 3.0 g of acrylic acid with 0.5 mL of sodium hydroxide solution (0.5 mol / L) to adjust the pH to about 7.0, to obtain solution B.

[0041] 4. Slowly add solution B dropwise to solution A while stirring for 30 minutes to form a homogeneous reaction mixture C.

[0042] 5. In a 60℃ water bath, add 0.2 g of ammonium persulfate (APS) to solution C, and continue to stir at a constant temperature for 45 min to obtain gel D.

[0043] 6. Transfer the obtained gel to a vacuum drying oven and dry at 80°C for 12-24 hours to obtain a solid gel block; after cooling, pulverize and filter through a 100-mesh sieve to obtain a powdered temperature-sensitive hydrogel fire extinguishing additive.

[0044] The FTIR spectra of methylcellulose, acrylic acid, carboxymethyl chitosan, and Example 1 (thermosensitive hydrogel fire extinguishing additive) are as follows: Figure 1 As shown, these correspond to methylcellulose (MC), acrylic acid (PAAS), carboxymethyl chitosan (CMCS), and Example 1 (MPC), respectively. Wavenumbers were 3600-3100 cm⁻¹. -1 A broad band can be observed in pure methylcellulose and carboxymethylcellulose within the range (corresponding to the stretching vibrations of OH and NH), at 3446.74 cm⁻¹. -1 The peak at 3282.67 cm⁻¹ is the stretching vibration peak of the -OH bond. The strong and broad absorption peak here indicates that the hydroxyl groups in methylcellulose undergo a binding reaction. -1The initial peak narrowed and a low-frequency shift occurred due to the stretching vibration of the -NH bonds, indicating the formation of numerous hydrogen bonds between carboxymethyl chitosan and other components. The spectrum shows that pure methyl cellulose peaks at 1452.36 cm⁻¹. -1 The characteristic bands disappeared, and no new characteristic bands appeared. At 2992 cm... -1 The weakening of the absorption peak at 1636 cm⁻¹ is related to the CH stretching vibration mode. All peaks in Example 1 are much weaker than those in the other three components, indicating the formation of numerous hydrogen bonds between methylcellulose, acrylic acid, and carboxymethyl chitosan. -1 The enhanced vibrational absorption at this point is due to the C=C stretching vibration absorption peak of methylcellulose, acrylic acid, and carboxymethyl chitosan, which corresponds to the peak at 1587.45 cm⁻¹ for carboxymethyl chitosan. -1 The result of peaks overlapping at the same position.

[0045] Example 2 The raw materials of the thermosensitive hydrogel fire extinguishing additive provided in this embodiment, by weight, include: 1 part thermosensitive substance, 0.5 parts thickener, 3 parts acrylic acid, 0.2 parts initiator, and 0.01 parts crosslinking agent. The thermosensitive substance is carboxymethyl cellulose, and the thickener is chitosan. The specific steps are as follows: 1. Place carboxymethyl cellulose, chitosan and crosslinking agent into a vacuum drying oven at 60℃ and dry for 6 hours to remove moisture. Then weigh and mix them according to the proportion to obtain mixed powder A.

[0046] 2. Slowly add the mixed powder A to 80 mL of deionized water, place it in a three-necked flask, and stir for 1.5 h in a water bath at 60 °C to obtain a high-viscosity transparent solution A.

[0047] 3. In another container, mix 3.0 g of acrylic acid with 0.5 mL of sodium hydroxide solution (0.5 mol / L) to adjust the pH to about 7.0, to obtain solution B.

[0048] 4. Slowly add solution B dropwise to solution A while stirring for 30 minutes to form a homogeneous reaction mixture C.

[0049] 5. In a 60℃ water bath, add 0.2 g of ammonium persulfate (APS) to solution C, and continue to stir at a constant temperature for 45 min to obtain gel D.

[0050] 6. Transfer the obtained gel to a vacuum drying oven and dry at 80°C for 12-24 hours to obtain a solid gel block; after cooling, pulverize and filter through a 100-mesh sieve to obtain a powdered temperature-sensitive hydrogel fire extinguishing additive.

[0051] like Figure 2As shown, under 200x magnification, the MPC hydrogel exhibits a distinct porous three-dimensional network structure, indicating that it has successfully formed a cross-linked structure, which facilitates hydration and swelling. The surface of Example 2 is mainly composed of C and O elements, with elemental contents of 36.58 at.% and 9.53 at.%, respectively, while Na... + It appeared on the surface of Example 2, with an element content of 19.51%.

[0052] Example 3 The raw materials of the thermosensitive hydrogel fire extinguishing additive provided in this embodiment, by weight, include: 1.5 parts of a thermosensitive substance, 0.8 parts of a thickener, 3 parts of acrylic acid, 0.2 parts of an initiator, and 0.02 parts of a crosslinking agent. The thermosensitive substance is carboxymethyl cellulose, and the thickener is chitosan. The specific steps are as follows: 1. Carboxymethyl cellulose, chitosan and N,N'-methylenebisacrylamide were placed in a vacuum drying oven at 60°C and dried for 6 hours to remove moisture. They were then weighed and mixed in proportion to obtain mixed powder A.

[0053] 2. Slowly add the mixed powder A to 80 mL of deionized water, place it in a three-necked flask, and stir for 1.5 h in a water bath at 60 °C to obtain a high-viscosity transparent solution A.

[0054] 3. In another container, mix 3.0 g of acrylic acid with 0.5 mL of sodium hydroxide solution (0.5 mol / L) to adjust the pH to about 7.0, to obtain solution B.

[0055] 4. Slowly add solution B dropwise to solution A while stirring for 30 minutes to form a homogeneous reaction mixture C.

[0056] 5. In a 60℃ water bath, add 0.2 g of ammonium persulfate (APS) to solution C, and continue to stir at a constant temperature for 45 min to obtain gel D.

[0057] 6. Transfer the obtained gel to a vacuum drying oven and dry at 80°C for 12-24 hours to obtain a solid gel block; after cooling, pulverize and filter through a 100-mesh sieve to obtain a powdered temperature-sensitive hydrogel fire extinguishing additive.

[0058] Example 4 The same method as in Example 2 was used, except that the amount of acrylic acid was changed to 4 parts.

[0059] Example 5 The same method as in Example 2 was used, except that the amount of thickener was changed to 0.9 parts.

[0060] Example 6 The same method as in Example 2 was used, except that the initiator was replaced with azobisisobutyronitrile (AIBN) instead of ammonium persulfate (APS). The gelation time of the prepared gel was slightly longer, and the crosslinking network was relatively loose.

[0061] Comparative Example 1 The method was the same as in Example 1, except that the amount of N,N'-methylenebis(acrylamide) was changed. The results showed that the final product could not form a stable gel structure, and the gel would separate into layers upon prolonged storage, making it unsuitable for long-term preservation.

[0062] Comparative Example 2 The method was the same as in Example 1, except that the amount of ammonium persulfate (APS) was changed to 0.005 parts. Similar to Comparative Example 1, stratification occurred, and the product could not be stored for a long time.

[0063] Comparative Example 3 The method used is the same as in Example 1, except that the mass ratio of the temperature-sensitive substance, thickener, acrylic monomer, initiator, and crosslinking agent is 0.2:0.1:1.5:0.05:0.001. The resulting system has a significantly reduced overall viscosity, making it difficult for the solution to form a continuous three-dimensional network structure, and the final product is a thin liquid.

[0064] The effectiveness of the above-mentioned fire extinguishing agent was verified through Examples 7 to 9. Viscosity test: according to GB / T5561-2012 Method for Determination of Viscosity of Chemical Reagents; Surface tension test: according to GB / T 5549-2010 Method for Determination of Surface Tension of Liquids (Pull-off Method); pH value test: according to GB / T 9724-2007 General Rules for Determination of pH Value of Chemical Reagents; Conductivity test: according to GB / T 14506.28-2010 Determination of Conductivity of Water (Conductivity Method); Extinguishing time and reignition test: according to GB 17945-2010 General Technical Conditions for Fire Extinguishing Agents in Fire Protection Products; Swelling rate test: according to a self-designed method, the dry powder fire extinguishing additive was added to deionized water, allowed to stand at room temperature for 60 minutes, weighed, and the swelling rate was calculated.

[0065] Example 7 The application process of the thermosensitive hydrogel fire extinguishing additive in this embodiment is as follows: the powdered thermosensitive colloids of each embodiment (example) and comparative example are added to water and stirred evenly to obtain a fire extinguishing agent with a mass concentration of 3%. The results are shown in Table 1.

[0066] Table 1. Specific Indicators for the Example

[0067] Example 8 The application process of the thermosensitive hydrogel fire extinguishing additive in this embodiment is as follows: the powdered thermosensitive colloids of each embodiment and comparative example are added to water and stirred evenly to obtain a fire extinguishing agent with a mass concentration of 4%. The results are shown in Table 2.

[0068] Table 2 Example Indicators

[0069] Example 9 The application process of the thermosensitive hydrogel fire extinguishing additive in this embodiment is as follows: the powdered thermosensitive colloids of each embodiment and comparative example are added to water and stirred evenly to obtain a fire extinguishing agent with a mass concentration of 5%. The results are shown in Table 3.

[0070] Table 3. Indicators of the Example

[0071] Example 10 Deionized water (fine water mist) and a commercial (water-based) fire extinguishing agent were used to conduct fire extinguishing experiments on lithium batteries, and temperature-sensitive hydrogel fire extinguishing additives (fire extinguishing agent with a mass concentration of 3%) were used to conduct fire extinguishing experiments on lithium batteries with thermal runaway.

[0072] like Figure 3-4 As shown, the battery module sprayed with fine water mist experienced thermal runaway at 1300 s, with the temperature reaching approximately 340 ℃. Immediate fire extinguishing was initiated after the thermal runaway, but the battery flames were not extinguished, and the cooling effect was not achieved. Due to the thermal spread from the first battery, the second battery experienced thermal runaway at 2600 s, with the temperature reaching 360 ℃. The battery module sprayed with a commercial water-based fire extinguishing agent experienced thermal runaway at 1280 s, with the temperature reaching approximately 340 ℃. Immediate fire extinguishing with a commercial water-based fire extinguishing agent was initiated after the thermal runaway. Although the battery flames were extinguished momentarily upon spraying, the cooling effect was not achieved, and the thermal spread continued. At 2400 s, the safety valve of the second LFP battery opened, accompanied by the generation of a large amount of smoke. As shown in Example 1, the battery module experienced thermal runaway in 850 seconds, with the temperature reaching approximately 603°C. Spraying the M / D extinguishing agent effectively extinguished the battery fire and simultaneously reduced the temperature on both sides of the battery to approximately 100°C. This extinguished the battery flames while suppressing the occurrence of thermal runaway and heat spread.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature-sensitive hydrogel fire extinguishing additive, characterized in that, The raw materials include a thermosensitive substance, a thickener, a crosslinking monomer, an initiator, and a crosslinking agent in a mass ratio of 0.3~1.7:0.2~0.9:2~10:0.1~0.3:0.01~0.

05. The thermosensitive substance is methylcellulose and / or carboxymethylcellulose, the thickener is carboxymethyl chitosan and / or chitosan, and the crosslinking monomer is acrylic acid.

2. The thermosensitive hydrogel fire extinguishing additive according to claim 1, characterized in that, It includes the following raw materials by weight: 0.5 to 1.5 parts of temperature-sensitive substance, 0.2 to 0.8 parts of thickener, 2 to 5 parts of crosslinking monomer, 0.1 to 0.2 parts of initiator, and 0.01 to 0.05 parts of crosslinking agent.

3. The temperature-sensitive hydrogel fire extinguishing additive according to claim 2, characterized in that, It includes the following raw materials by weight: 0.8 to 1 part of a thermosensitive substance, 0.4 to 0.5 parts of a thickener, 3 to 4 parts of acrylic acid, 0.1 to 0.2 parts of an initiator, and 0.01 to 0.02 parts of a crosslinking agent, wherein the thermosensitive substance is methylcellulose or carboxymethylcellulose, and the thickener is carboxymethyl chitosan or chitosan.

4. The thermosensitive hydrogel fire extinguishing additive according to any one of claims 1-3, characterized in that, The crosslinking agent is N,N'-methylenebis(acrylamide) and / or polyethylene glycol diacrylate.

5. The thermosensitive hydrogel fire extinguishing additive according to any one of claims 1-4, characterized in that, The initiator is ammonium persulfate and / or azobisisobutyronitrile.

6. The method for preparing the thermosensitive hydrogel fire extinguishing additive according to any one of claims 1-5, characterized in that, Includes the following steps: 1) Mix dried methylcellulose, carboxymethyl chitosan, and a crosslinking agent to obtain a mixed powder; 2) Add the mixed powder to deionized water, heat and stir to obtain solution A; 3) Adjust the pH of the acrylic acid to obtain solution B; 4) Mix solution A and solution B and stir to obtain mixed solution C; 5) The mixed solution C and the initiator are mixed and reacted to obtain a thermosensitive hydrogel; 6) The thermosensitive hydrogel is dried and then pulverized.

7. The preparation method of the temperature-sensitive hydrogel fire extinguishing additive according to claim 6, characterized in that, In step 2), the heating is carried out in a water bath at 55~65℃, and the stirring time is 1~2 hours; And / or, in step 3), the pH is adjusted to 6.5-7.5 using sodium hydroxide solution; And / or, in step 4), the stirring time is 20~40 min; And / or, in step 5), the reaction temperature is 55~65℃ and the reaction time is 30~60min; And / or, in step 6), the thermosensitive hydrogel is dried at 70~90℃ for 12~24h to obtain a solid gel block; the thermosensitive hydrogel is pulverized and passed through a 90~100 mesh sieve.

8. A hydrogel fire extinguishing agent, characterized in that, This includes the thermosensitive hydrogel fire extinguishing additive as described in any one of claims 1-5 or the thermosensitive hydrogel fire extinguishing additive obtained by the preparation method described in claim 6 or 7.

9. The hydrogel fire extinguishing agent according to claim 8, characterized in that, In the hydrogel fire extinguishing agent, the mass fraction of the temperature-sensitive hydrogel fire extinguishing additive is 3% to 6%.

10. The application of the hydrogel fire extinguishing agent according to claim 8 or 9 in extinguishing lithium battery fires.

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