A lithium battery dual-component fire extinguishing agent and a fire extinguishing composition used thereby

Abstract

The application provides a lithium battery dual-component fire extinguishing agent and a fire extinguishing composition used by the lithium battery dual-component fire extinguishing agent. The fire extinguishing composition provided by the application comprises, by weight, 1-2 parts of guar gum, 2-3 parts of polyvinyl alcohol, 3-4 parts of acrylamide, 2-3 parts of methacrylic acid, 1.5-2 parts of a skeleton supporting material, 1.3-2.5 parts of a crosslinking agent and 0.2-0.3 parts of an initiator. The fire extinguishing composition provided by the application has a stable three-dimensional structure, the evaporation of water in the structure can absorb a large amount of heat, and the volume is reduced with the evaporation of water to adhere to the surface of the battery to form carbon deposition, so that the effect of air isolation and combustion prevention is achieved, the fire resistance is improved, and the afterburning is prevented; the combustion of the polymer consumes combustible gas in the process of carbonization under heat, and the combustion reaction is prevented. The lithium battery dual-component fire extinguishing agent is prepared into a fire extinguishing hydrogel or a dual-component fire extinguishing agent comprising a water-based component and a hydrogel component, and the lithium battery dual-component fire extinguishing agent has multiple synergistic fire extinguishing effects on the lithium battery, and efficient fire extinguishing of the lithium battery is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional materials, and particularly relates to a lithium battery dual-component fire extinguishing agent and a fire extinguishing composition used by the lithium battery dual-component fire extinguishing agent. BACKGROUND

[0002] Lithium ion batteries have the advantages of large energy density, long cycle life, pollution-free operation, etc., and are widely used in the fields of electric power storage and electric vehicles. However, under abuse conditions, lithium ion batteries are prone to thermal runaway, releasing a large amount of heat and harmful flammable gases. Electric vehicle fires caused by battery thermal runaway have become a thorny problem faced by the fire department. In recent years, lithium ion battery fire accidents have occurred frequently, and the consequences of the fire accidents are extremely serious. Therefore, it is of great significance to develop a fast and efficient fire extinguishing agent for extinguishing lithium battery fires and inhibiting the development of thermal runaway.

[0003] At present, the research on lithium ion battery fire extinguishing technology mainly focuses on perfluorohexanone, liquid nitrogen, gas fire extinguishing agent and water-based fire extinguishing agent. By comparing and analyzing the inhibition effect of carbon dioxide and fine water mist on ternary lithium battery fire, it is found that the battery after being affected by carbon dioxide has a rekindling, while in the experiment using fine water mist, the battery does not rekindle, and the fine water mist can greatly reduce the temperature of the battery; compared with fine water mist, perfluorohexanone can quickly extinguish the fire, but as the concentration of the fire extinguishing agent decreases, the battery subsequently rekindles, while the cooling effect of fine water mist is better than that of perfluorohexanone, but it has the disadvantage of large water consumption, which is difficult to carry out practical application. Gas fire extinguishing agent can effectively inhibit the thermal runaway of lithium ion batteries in a confined space, but it is not suitable for extinguishing fires in an open space such as an electric vehicle fire. Water-based fire extinguishing agent has the characteristics of high specific heat capacity and strong insulation, and has more efficient fire extinguishing performance, but its water retention and covering capacity are very limited.

[0004] A hydrogel for temporarily plugging an oil pipeline is provided in a Chinese patent with publication number CN111978489B, which is obtained by grafting, copolymerizing and chemically cross-linking reactants including gelatin, water, amide monomer, acrylic monomer, neutralizing agent, initiator, two-component cross-linking agent, thickening agent and preservative, wherein the mass percentage of each substance in the reactants is as follows: two-component cross-linking agent 0.5%-0.8%, initiator 0.1-0.2%; gelatin 1%-2%, amide monomer 2%-3%, acrylic monomer 1.5%-2%, thickening agent 0.2%-0.5%, neutralizing agent 1.5%-2%, preservative 0.1%-0.3%, and the balance is water. In the patent document, the use of a double cross-linking agent for chemical cross-linking during the reaction makes the structure of the product more stable, and then a surfactant is added to enhance the performance of the product, finally generating a high-viscosity and high-strength hydrogel.

[0005] The water gel obtained by the prior art still has the technical problems of poor fire extinguishing and cooling effect, high viscosity, poor flowability, and inability to effectively cover the battery to isolate the fire and interrupt the release of gas by the battery thermal runaway to intensify the combustion. SUMMARY

[0006] The first object of the present application is to overcome the technical problems of poor fire extinguishing and cooling effect, inability to effectively cover the battery to isolate the fire and interrupt the release of gas by the battery thermal runaway to intensify the combustion in the prior art, and to provide a fire extinguishing composition, which comprises, by weight, 1-2 parts of guar gum, 2-3 parts of polyvinyl alcohol, 3-4 parts of acrylamide, 2-3 parts of methacrylic acid, 1.5-2 parts of a skeleton support material, 1.3-2.5 parts of a crosslinking agent, and 0.2-0.3 parts of an initiator.

[0007] The fire extinguishing composition provided by the present application can react to form a high molecular material with a three-dimensional spatial structure under the action of a crosslinking agent and an initiator, and the three-dimensional structure of the high molecular material is more stable by adding a skeleton support material, which improves the flame retardancy and prevents reignition. The copolymerization of methacrylic acid can make the toughness and wrapping ability of the product after dehydration stronger, and the wrapping layer is not easy to crack after water evaporation, thereby increasing the fire extinguishing efficiency and reducing the probability of reignition. The evaporation of water in the structure of the fire extinguishing composition provided by the present application can absorb a large amount of heat, and the volume decreases as the water evaporates to form carbon deposition on the surface of the battery, thereby achieving the effect of isolating air and blocking combustion. At the same time, the high polymer will consume combustible gas during the process of carbonization by heating, thereby preventing the combustion reaction from proceeding.

[0008] In some embodiments of the present application, the skeleton support material is selected from nano-silicon dioxide.

[0009] The use of the above-mentioned skeleton support material can effectively improve the stability of the three-dimensional structure of the fire extinguishing composition, thereby providing stable and efficient fire extinguishing performance for the fire extinguishing composition, especially the late fire extinguishing performance, and avoiding the incomplete fire extinguishing and reignition caused by the accumulation of burning materials during the fire extinguishing process, which destroys the three-dimensional structure of the fire extinguishing composition.

[0010] In some embodiments of the present application, the raw material further comprises 2-3 wt% of a neutralizing agent.

[0011] In some embodiments of the present application, the neutralizing agent is selected from at least one of sodium hydroxide and bicarbonate.

[0012] The application adopts a neutralizing agent, especially a mild bicarbonate as the neutralizing agent, such as at least one of sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, and ammonium bicarbonate, for adjusting the pH of the fire extinguishing composition, which can slowly and accurately adjust the pH, make the system neutral, avoid corrosion to the fire extinguishing object, and ensure the safe use of the fire extinguishing composition, and avoid harm to the user caused by the pH.

[0013] In some embodiments of the application, the raw materials further include 0.1-0.3 parts of a preservative by weight; the application adopts a preservative, which can effectively prolong the storage time of the fire extinguishing composition.

[0014] In some embodiments of the application, the preservative is at least one of potassium sorbate and sodium benzoate.

[0015] In some embodiments of the application, the crosslinking agent is at least one of N-methylol acrylamide and ethylene glycol dimethacrylate.

[0016] The second object of the application is to provide a preparation method of the fire extinguishing composition, which comprises:

[0017] Step 1: mixing and dissolving guar gum, polyvinyl alcohol, acrylamide, and a skeleton support material to obtain a first solution;

[0018] Step 2: dissolving methacrylic acid to obtain a second solution;

[0019] Step 3: pouring the second solution into the first solution, mixing uniformly, adding a crosslinking agent and an initiator, and performing graft copolymerization to obtain the fire extinguishing composition;

[0020] In some embodiments of the application, in step 1, the guar gum, polyvinyl alcohol, acrylamide, and skeleton support material are dissolved at 50-70°C to obtain the first solution.

[0021] In some embodiments of the application, in step 2, the methacrylic acid is dissolved at 30-50°C.

[0022] In some embodiments of the application, in step 2, after the methacrylic acid is completely dissolved, a neutralizing agent is added for neutralization, and the neutralization degree is 80-90%, to obtain the second solution.

[0023] In some embodiments of the application, in step 3, the graft copolymerization is performed at 70-80°C for 1h.

[0024] In some embodiments of the application, in step 3, after the graft copolymerization is performed for 1h, a preservative is added to obtain the fire extinguishing composition.

[0025] The fire extinguishing composition obtained by the preparation method provided by the present invention is gel-like and has a stable three-dimensional structure, which provides stable and efficient fire extinguishing performance from a structural perspective.

[0026] A third objective of this invention is to provide the application of the fire extinguishing composition or the fire extinguishing composition obtained by the preparation method in the field of batteries, preferably the battery being selected from lithium batteries.

[0027] The fourth objective of this invention is to provide a fire extinguishing hydrogel, the raw materials of which include 10-20 wt% of the fire extinguishing composition or the fire extinguishing composition obtained by the preparation method.

[0028] The fire-extinguishing hydrogel provided by this invention is insoluble in water, but its molecular structure can adsorb a large amount of water. During the fire extinguishing process of lithium-ion batteries, the evaporation of water in its structure can absorb a large amount of heat, effectively reducing the temperature of the battery surface. Simultaneously, the fire-extinguishing hydrogel provided by this invention has strong water retention and high adhesion. During the fire extinguishing process, while the volume of the fire-extinguishing composition decreases, it can adhere to the battery surface to form carbon deposits, thereby achieving the effect of isolating air and blocking combustion, preventing reignition. Sulfonic acid groups are introduced into the raw materials and copolymer products during the synthesis process. The sulfonyl free radicals generated after thermal decomposition are very active and can quickly combine with the hydroxyl free radicals released during battery combustion, thereby terminating the chain reaction. Therefore, the fire-extinguishing hydrogel provided by this invention achieves multiple synergistic fire extinguishing effects on lithium batteries, realizing highly efficient fire extinguishing of lithium batteries.

[0029] The fifth objective of this invention is to provide a two-component fire extinguishing agent comprising 30-40 wt% of a water-based fire extinguishing component and 60-70 wt% of the fire extinguishing hydrogel; the water-based fire extinguishing agent and the fire extinguishing hydrogel are stored separately.

[0030] In some embodiments of the present invention, the water-based fire extinguishing agent comprises 1-2 wt% dodecyl phosphate monoester.

[0031] The present invention provides a two-component fire extinguishing agent comprising an aqueous component and a hydrogel component, for extinguishing fires involving lithium-ion batteries. It combines the rapid cooling effect of aqueous fire extinguishing agents with the hydrogel component's limitations, such as the aqueous component only reaching the outer surface of the battery and its limited water retention and coverage. In the initial stage of use, the aqueous component significantly reduces the battery temperature, providing efficient cooling. In the later stages, the stable three-dimensional structure of the hydrogel component prevents uncontrolled high temperatures and the re-ignition of released flammable gases. The two-component fire extinguishing agent provided by this invention provides multiple synergistic fire extinguishing effects for lithium batteries, further achieving highly efficient fire suppression for lithium batteries.

[0032] The fire extinguishing composition prepared by the method of this invention comprises an aqueous component and a hydrogel component. The main function of the aqueous component is to reduce the battery temperature through water evaporation, thereby reducing subsequent reactions caused by battery thermal runaway. The hydrogel component is gel-like, and the free water and bound water in its molecular structure further cool the battery. Simultaneously, after water evaporation, the hydrogel covers the battery surface, providing insulation and cooling. Therefore, the fire extinguishing composition exhibits multiple fire extinguishing effects during the fire extinguishing process. Detailed Implementation

[0033] 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 in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. 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.

[0034] This invention provides a two-component fire extinguishing agent for lithium batteries, comprising 60-70 wt% hydrogel component and 30-40 wt% aqueous component; the two components are stored separately.

[0035] The raw materials of the hydrogel component, by weight, include: 1-2 parts guar gum, 2-3 parts polyvinyl alcohol, 3-4 parts acrylamide, 2-3 parts methacrylic acid, 2-3 parts neutralizing agent, 1.5-2 parts skeleton support material, 1-2 parts crosslinking agent N-hydroxymethylacrylamide, 0.3-0.5 parts crosslinking agent ethylene glycol dimethacrylate, 0.2-0.3 parts initiator, 0.1-0.3 parts preservative, and water; the sum of the weight parts of each substance is 100 parts. That is, the above raw materials by weight can also be expressed as mass percentage, which will be explained below as weight percentage.

[0036] The preparation process of the hydrogel component is as follows:

[0037] Step A: Preparation of aqueous components: Dissolve 1%-2% (by mass) of dodecyl phosphate monoester by stirring at 40-60°C to obtain aqueous components;

[0038] Step B: Preparation of hydrogel components:

[0039] Step 1: Dissolve and stir 1%-2% guar gum, 2%-3% polyvinyl alcohol, 3%-4% acrylamide, and 1.5%-2% of the skeleton support material at 50-70℃ to obtain the first solution;

[0040] Step 2: Dissolve and stir 2%-3% methacrylic acid at 30-50℃, and add a neutralizing agent to neutralize it to a degree of neutralization of 80-90% to obtain the second solution;

[0041] Step 3: Pour the second solution into the first solution and stir to mix. Add 0.5%-0.8% of crosslinking agent and 0.2%-0.3% of initiator, and carry out graft copolymerization reaction at 70-80℃. After reacting for 1 hour, add 0.1%-0.3% of preservative to obtain the hydrogel component.

[0042] Step C: Cool the aqueous component and the hydrogel component to room temperature respectively to obtain the two-component fire extinguishing agent.

[0043] The framework support material is selected from nano-silica; the crosslinking agent is selected from N-hydroxymethylacrylamide and ethylene glycol dimethacrylate; the neutralizing agent is selected from bicarbonates (such as sodium bicarbonate, potassium bicarbonate, calcium bicarbonate and ammonium bicarbonate) and sodium hydroxide; and the preservative is selected from potassium sorbate and sodium benzoate.

[0044] The two-component fire extinguishing agent provided by the present invention is used by mixing 30-40 wt% of the aqueous component with 60-70 wt% of the hydrogel component, which can be used for extinguishing fires involving batteries such as lithium batteries, and has excellent fire extinguishing performance.

[0045] All chemical raw materials involved in this invention are chemically pure and were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0046] The polyvinyl alcohol was purchased from Maclean Biochemical Technology Co., Ltd., with a degree of alcoholysis of 88-89 mol% and a viscosity of 3.2-3.8 mPa·s.

[0047] Example 1

[0048] This embodiment 1 provides a two-component fire extinguishing agent, including an aqueous component and a hydrogel component.

[0049] The aqueous component consists of 20g of dodecyl phosphate monoester and 980g of water. The preparation method is as follows: the dodecyl phosphate monoester is stirred and dissolved at 40-60℃ to obtain the aqueous component.

[0050] The hydrogel component consists of the following raw materials: 10g guar gum, 20g polyvinyl alcohol, 30g acrylamide, 20g methacrylic acid, 20g sodium bicarbonate neutralizer, 15g skeleton support material, 10g N-hydroxymethylacrylamide crosslinking agent, 3g ethylene glycol dimethacrylate crosslinking agent, 2g ammonium persulfate initiator, 1g sodium benzoate preservative, and 872g water.

[0051] The preparation method of the hydrogel component is as follows:

[0052] Step 1: Dissolve and stir guar gum, polyvinyl alcohol, acrylamide, and the skeletal support material at 50-70℃ to obtain the first solution;

[0053] Step 2: Dissolve and stir methacrylic acid at 30-50℃, and add a neutralizing agent to neutralize it to a degree of neutralization of 80-90%, thus obtaining the second solution;

[0054] Step 3: Pour the second solution into the first solution and stir to mix. Add the crosslinking agent and initiator, and carry out the graft copolymerization reaction at 70-80℃. After reacting for 1 hour, add the preservative to obtain the hydrogel component.

[0055] The two-component fire extinguishing agent provided in this embodiment stores the aqueous component and the hydrogel component separately. For example, they can be stored in the two chambers of the fire extinguishing canister. When needed, 40wt% of the aqueous component and 60wt% of the hydrogel component are mixed through a specific operation, which can then be used to extinguish fires involving lithium batteries.

[0056] Example 2

[0057] This embodiment provides a fire extinguishing agent that is basically the same as that in Embodiment 1, except that the water-based component is not added. That is, the hydrogel component (i.e., the fire extinguishing hydrogel provided by this invention) is used as the fire extinguishing agent.

[0058] Comparative Example 1

[0059] This comparative example provides a two-component fire extinguishing agent, which is basically the same as Example 1, except that no skeleton support material is added to the raw materials of the hydrogel component, that is, nano-silica is replaced with an equal mass of water.

[0060] Comparative Example 2

[0061] This comparative example provides a two-component fire extinguishing agent, which is basically the same as Example 1, except that polyvinyl alcohol is not added to the raw materials of the hydrogel component; that is, it is replaced with an equal mass of water.

[0062] Comparative Example 3

[0063] This comparative example provides a fire extinguishing agent that is basically the same as that in Example 1, except that the hydrogel component is not added, that is, the water-based component is used as the fire extinguishing agent.

[0064] Test case

[0065] Test subjects: Two-component fire extinguishing agents or fire extinguishing hydrogels obtained in each embodiment and comparative example.

[0066] Experimental Method: To verify the performance of the extinguishing agent, a cylindrical lithium-ion-graphite battery with a diameter of 18 mm and a height of 65 mm was used for thermal runaway extinguishing experiments. The battery capacity was 3 Ah, and the nominal voltage was 4.2 V. First, the battery was fully charged and discharged multiple times using a charging device, and then charged to 100% state of charge for the experiment. During the test, four batteries were placed side-by-side close together, with the leftmost battery experiencing thermal runaway. The effects of thermal runaway on the two adjacent batteries were observed. The extinguishing performance of the control group, fine water mist, perfluorohexanone, and the prepared hydrogel were compared in the experiment. During the experiment, once the battery safety valve was observed to open, the heating rod was turned off, and the battery heating was stopped. Subsequently, when the battery emitted a jet fire, the extinguishing agent was immediately released to extinguish the battery fire.

[0067] Experimental results: The data obtained during the test are shown in the table below.

[0068] Table 1 Fire Extinguishing Data for Different Extinguishing Agents

[0069]

[0070] As shown in Table 1, the two-component fire extinguishing agent with hydrogel provided by this invention extinguishes lithium battery fires in a shorter time. After extinguishing, it not only prevents reignition but also blocks the impact of battery runaway on surrounding battery packs. Experimental results from Examples 1-2 and Comparative Example 3 show that the main fire extinguishing component of the two-component fire extinguishing agent is the hydrogel component. The main function of the aqueous component is to reduce the temperature of the battery surface. In Comparative Example 3, the battery reignited after the hydrogel component was missing, which also triggered runaway of surrounding batteries. Experimental results from Examples 1 and Comparative Example 1 show that although the fire extinguishing agent lacking the skeletal support material can extinguish the fire, the structural instability reduces the insulating and cooling effect of the hydrogel covering the battery surface after water evaporation, leading to an increase in temperature. Results from Examples 1 and Comparative Example 2 show that the addition of polyvinyl alcohol helps improve fire extinguishing efficiency and reduce the maximum temperature of the thermally runaway battery after fire extinguishing.

[0071] In other embodiments of the present invention, when preparing the fire extinguishing composition, neutralizing agents and / or antifungal agents may be omitted, and they can be replaced with an equal amount of water. The neutralizing agent is used to adjust the pH of the fire extinguishing composition to prevent corrosion of the fire-fighting target and to ensure the safe use of the fire extinguishing composition, avoiding harm to users due to pH levels. Therefore, even if the embodiments of the present invention do not provide relevant examples, those skilled in the art can expect that the resulting hydrogel fire extinguishing agent can achieve stable fire extinguishing performance without adding a neutralizing agent. Similarly, even if the embodiments of the present invention do not provide relevant examples without adding an antifungal agent, those skilled in the art can expect that the resulting hydrogel fire extinguishing agent can achieve stable fire extinguishing performance without adding an antifungal agent.

[0072] 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 fire extinguishing composition, characterized in that, By weight, its raw materials include: 1-2 parts guar gum, 2-3 parts polyvinyl alcohol, 3-4 parts acrylamide, 2-3 parts methacrylic acid, 1.5-2 parts skeleton support material, 1.3-2.5 parts crosslinking agent, 0.2-0.3 parts initiator, 2-3 parts neutralizer, and 0.1-0.3 parts preservative; The skeleton support material is nano-silica; The crosslinking agent comprises N-hydroxymethylacrylamide and ethylene glycol dimethacrylate in a mass ratio of (2-7):

1.

2. The fire extinguishing composition according to claim 1, characterized in that, The neutralizing agent is selected from at least one of sodium hydroxide and bicarbonate.

3. The fire extinguishing composition according to claim 2, characterized in that, The bicarbonate is selected from at least one of potassium bicarbonate, sodium bicarbonate, calcium bicarbonate, and ammonium bicarbonate.

4. The fire extinguishing composition according to claim 1, characterized in that, The preservative is selected from at least one of potassium sorbate and sodium benzoate.

5. A method for preparing the fire extinguishing composition according to any one of claims 1-4, characterized in that, include: Step 1: Mix and dissolve guar gum, polyvinyl alcohol, acrylamide, and the skeletal support material to obtain the first solution; Step 2: Dissolve methacrylic acid. After the methacrylic acid is completely dissolved, add a neutralizing agent to neutralize it to a degree of neutralization of 80-90%, thus obtaining the second solution. Step 3: Pour the second solution into the first solution, mix well, add a crosslinking agent and an initiator, and carry out a graft copolymerization reaction. After the graft copolymerization reaction has been carried out for 1 hour, add a preservative to obtain the fire extinguishing composition.

6. The preparation method according to claim 5, characterized in that, In step 1, the guar gum, polyvinyl alcohol, acrylamide, and skeleton support material are dissolved at 50-70°C to obtain the first solution; And / or, in step 2, the methacrylic acid is dissolved at 30-50°C; And / or, in step 3, the graft copolymerization reaction is carried out at 70-80°C for 1 hour.

7. The application of the fire extinguishing composition according to any one of claims 1-4 or the fire extinguishing composition obtained by the preparation method according to claim 5 or 6 in the field of batteries.

8. The application according to claim 7, characterized in that, The battery is a lithium battery.

9. A two-component fire extinguishing agent, characterized in that, It comprises 30-40 wt% of a water-based fire extinguishing component and 60-70 wt% of the fire extinguishing composition component according to any one of claims 1-4; the water-based fire extinguishing component and the fire extinguishing composition component are stored separately.

10. The two-component fire extinguishing agent according to claim 9, characterized in that, The water-based fire extinguishing component includes 1-2 wt% dodecyl phosphate monoester.

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