Fire extinguishing composition and battery system using the same

Abstract

The application provides a fire extinguishing composition and a battery system using the same. The fire extinguishing composition comprises a fire extinguishing agent and a temperature-sensitive material. The fire extinguishing agent is a fluorine-based fire extinguishing agent with a fluorine-containing active group. The temperature-sensitive material comprises a hydrogel polymer, and the hydrogel polymer is an N-isopropyl acrylamide hydrogel polymer and / or a modified product thereof. The mass ratio of the fire extinguishing agent to the temperature-sensitive material is 1-10:5. The fire extinguishing composition can effectively extinguish fire and prevent a high-temperature heat source from reigniting.

Description

Technical Field

[0001] This invention belongs to the field of fire extinguishing technology, specifically relating to a fire extinguishing composition and a battery system using the same. Background Technology

[0002] Among various disasters, fire is one of the most frequent and widespread major threats to public safety and social development. In the face of fires caused by intense, sudden, or unwanted combustion, it is essential to control the fire promptly and minimize the loss of life and property.

[0003] New energy battery systems generate a lot of heat during charging and discharging, and are prone to thermal runaway, which can lead to fires and explosions. The main reason is that when the battery overheats, short-circuits, or is squeezed, the heat generation and dissipation of the battery become unbalanced, inducing side reactions in the electrode materials and electrolyte inside the battery, producing a large amount of flammable and toxic gases.

[0004] After a battery experiences thermal runaway, people often use fire extinguishing agents to put out the fire. These agents can effectively disrupt combustion conditions, lower the temperature of the burning object, and slow the spread of the fire. However, while the surface temperature of the battery may decrease, the internal temperature may continue to rise. If only fire extinguishing agents are used to extinguish the fire, the battery is prone to reignition.

[0005] Therefore, in order to solve the above problems, it is necessary to develop a fire extinguishing composition with good fire extinguishing performance and to prevent battery reignition, specifically for the protection against thermal runaway of new energy batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a fire extinguishing composition and a battery system using the same, which can effectively extinguish fires and prevent reignition of high-temperature heat sources.

[0007] According to a first aspect of the present invention, a fire extinguishing composition is provided, comprising a fire extinguishing agent and a temperature-sensitive material; the fire extinguishing agent is a fluorine-based fire extinguishing agent having a fluorine-containing active group; the temperature-sensitive material comprises a hydrogel polymer, wherein the hydrogel polymer is an N-isopropylacrylamide hydrogel polymer and / or a modified thereof; and the fire extinguishing agent: temperature-sensitive material ratio is 1 to 10:5 by mass.

[0008] When no fire occurs, i.e., the ambient temperature is below the phase transition temperature of the extinguishing composition, both the extinguishing agent and the temperature-sensitive material are in a liquid state, and their solubility is low, easily allowing them to coexist in a stratified manner. When a fire occurs, the extinguishing agent absorbs a large amount of heat and vaporizes, reducing the temperature of the fire area and thus extinguishing the flames. The combustion process involves a complex chain reaction, with active free radicals continuously catalyzing the combustion reaction. The extinguishing agents used in this solution are all fluorinated extinguishing agents with fluorine-containing active groups. These fluorine-containing active groups combine with active free radicals in the flame to form inactive compounds, thus interrupting the combustion chain reaction and preventing the flame from continuing to burn. However, after vaporization, the extinguishing agent is easily swept away from the fire area by flowing smoke, making the flame prone to reignition. Therefore, this solution also employs a temperature-sensitive material for fire extinguishing. This temperature-sensitive material is an environmentally responsive polymer material that is sensitive to changes in ambient temperature. This temperature-sensitive hydrogel is liquid at low temperatures and condenses into a gel-like substance at high temperatures; this state change is reversible with temperature. Liquid temperature-sensitive materials are easier to store and release onto the surface of high-temperature heat sources, where they absorb heat and transform into a gel. This gel-like material adheres to the surface of the heat source, lowering its temperature through heat transfer. It not only absorbs more heat but also forms a non-slip, heat-dissipating fire-resistant layer on the heat source surface, effectively isolating the air from direct contact with the heat source and preventing reignition. Furthermore, when the mass ratio of extinguishing agent to temperature-sensitive material falls within the aforementioned range, the resulting extinguishing composition exhibits both excellent extinguishing and reignition-preventing properties. Insufficient extinguishing agent results in inadequate extinguishing performance, while insufficient temperature-sensitive material makes the heat source prone to reignition and re-ignition. In summary, the fire extinguishing composition provided in this solution not only utilizes the physical means of endothermic vaporization of the extinguishing agent and the chemical means of interrupting the combustion chain reaction, but also the physical means of isolating the fire source through the gel-like substance formed by the phase change of the temperature-sensitive material, further preventing reignition. This effectively controls the fire, slows its spread, and prevents reignition, thereby achieving the goal of completely extinguishing the flames. Secondly, since the temperature-sensitive response temperature of the above-mentioned fire extinguishing composition can be as low as 90-100℃, while the initial temperature at which a large number of side reactions occur between the electrolyte and active materials in a battery, leading to thermal runaway, is generally above 100℃, this product can also be used for the safety protection of battery thermal runaway. When the battery temperature is too high, the fire extinguishing composition takes effect, effectively reducing the battery heat, achieving heat dissipation, and preventing the battery from igniting or exploding due to rising ambient temperature.

[0009] Preferably, the lower critical solution temperature of the hydrogel polymer is above 70°C. The temperature range in which a thermosensitive material transforms from a liquid to a gel is called the volume phase transition temperature (VPTT), and the lowest temperature value within the VPTT is called the lower critical solution temperature (LCST). The lower critical solution temperature of typical thermosensitive materials is 40–60°C. However, when a thermosensitive material with a lower critical solution temperature above 70°C is used to prepare a fire extinguishing composition, this thermosensitive material can be matched with the vaporization extinguishing temperature of the extinguishing agent: when a fire occurs, as the ambient temperature rises, the fluorinated extinguishing agent in the fire extinguishing composition (vaporization temperature 50–90°C) will vaporize first, extinguishing the fire source. Then, the thermosensitive material is released in liquid form onto the surface of the high-temperature heat source and transforms into a gel-like substance on the surface, preventing the high-temperature heat source from reigniting. Secondly, this fire extinguishing composition can be applied to the safety control of thermal runaway in power batteries. The thermal runaway temperature of power batteries is generally 80-100℃, which matches the low critical melting temperature of the temperature-sensitive material. When thermal runaway occurs in a power battery, the temperature of the power battery is higher than the low critical melting temperature of the temperature-sensitive material, thereby ensuring that the temperature-sensitive material released onto the surface of the power battery can undergo a phase change, promptly blocking the spread of fire, preventing the fire from rapidly developing from a single point of ignition to a total fire, and avoiding more power batteries from experiencing thermal runaway.

[0010] Preferably, the low critical dissolution temperature of the hydrogel polymer is 70–95°C.

[0011] Preferably, the temperature-sensitive material is an aqueous solution of a hydrogel polymer, with a concentration of the hydrogel polymer of not less than 0.5 wt%. The temperature-sensitive material satisfies the following conditions: at temperatures above 95°C, the viscosity of the temperature-sensitive material is ≥4000 mPa·s; at temperatures below 55°C, the viscosity of the temperature-sensitive material is ≤1000 mPa·s. Using aqueous solutions of hydrogel polymers of different concentrations as the temperature-sensitive material results in different viscosities. As the concentration of the hydrogel polymer increases, the viscosity of the temperature-sensitive material measured under the same conditions also increases. When the temperature-sensitive material meets the condition of viscosity ≤1000 mPa·s below 55°C, it indicates that the temperature-sensitive material has excellent fluidity at temperatures below 55°C, allowing it to be smoothly released onto the surface of a high-temperature heat source, thereby expanding the coverage and adhesion range of the high-temperature heat source. Furthermore, it absorbs heat from the heat source and transforms into a gel-like substance. Secondly, the absorption of heat from the heat source surface by the temperature-sensitive material can also prevent the heat source from further heating up and turning into an ignition source. Secondly, when the temperature-sensitive material is above its low critical dissolution temperature, the viscosity of the temperature-sensitive material that has been transformed into a gel-like substance is greater than or equal to 4000 mPa·s. At this time, the fluidity of the temperature-sensitive material is poor, and it can adhere well to the surface of the high-temperature heat source. It is not easy to be directly lost from the surface of the heat source, thereby effectively isolating the air from the heat source and further reducing the possibility of the fire source reigniting.

[0012] Preferably, the hydrogel polymer is an acrylic acid-modified N-isopropylacrylamide hydrogel polymer. The preparation of the acrylic acid-modified N-isopropylacrylamide hydrogel polymer includes the following steps: S1. Prepare an aqueous solution of sodium acrylate with a pH of 6.5-7.5, wherein the sodium acrylate content in the aqueous solution is 5wt%-15wt%; S2. Dissolve N-isopropylacrylamide in water to prepare an aqueous solution of N-isopropylacrylamide, wherein the N-isopropylacrylamide content in the aqueous solution is 5wt%-15wt%; S3. Take the aqueous solution of sodium acrylate and the aqueous solution of N-isopropylacrylamide according to the mass ratio of sodium acrylate: N-isopropylacrylamide = 1.3: 5-12, and then, under the protection of an inert atmosphere, add the aqueous solution of sodium acrylate, a crosslinking agent, an initiator, and a crosslinking accelerator to the aqueous solution of N-isopropylacrylamide, and mix them evenly to obtain the reaction base liquid; S4. Heat the reaction base liquid to a temperature of 75-95°C and keep it at that temperature to obtain the hydrogel polymer.

[0013] The hydrogel polymer prepared by the above method has a large number of hydrogen bonds in its chemical structure. When the ambient temperature is higher than or equal to the LCST, the hydrogen bonds are broken, the hydrophobic association of the hydrophobic groups is enhanced, water molecules are expelled, and the hydrogel polymer transforms into a gel state. The hydrogel polymer prepared by this method, when used as a temperature-sensitive material, exhibits good compatibility with the fire extinguishing agent, with no mutual reaction, thereby improving the storage stability of the fire extinguishing composition. Furthermore, this preparation method is simple to operate and operates under mild conditions, which is conducive to large-scale production. Secondly, by adjusting the mass ratio and concentration of sodium acrylate aqueous solution and N-isopropylacrylamide aqueous solution, the lower critical dissolution temperature of the hydrogel polymer can be adjusted. When the above specific mass ratio and concentration are met, the lower critical dissolution temperature of the prepared hydrogel polymer is above 70°C, resulting in better performance when combined with the fire extinguishing agent, and improving the fire extinguishing performance and reignition prevention properties of the fire extinguishing composition.

[0014] Preferably, the number-average molecular weight of the hydrogel polymer is 250,000 to 500,000 Daltons.

[0015] Preferably, the fluorinated fire extinguishing agent includes at least one selected from perfluorohexanone, perfluorobutyl methyl ether, methyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, pentafluorobutane, and decafluoro-3-methoxy-4-(trifluoromethyl)pentane. Firstly, the aforementioned fluorinated fire extinguishing agents exhibit excellent fire extinguishing performance, rapid and efficient extinguishing of fire sources, and minimal damage to the fire source during extinguishing. Secondly, the low miscibility between the aforementioned fluorinated fire extinguishing agents and temperature-sensitive materials avoids mutual dilution, thereby improving the storage stability of the fire extinguishing composition.

[0016] Preferably, the fluorinated extinguishing agent is perfluorohexanone. Perfluorohexanone is a green and environmentally friendly extinguishing agent with high extinguishing efficiency. Extinguishing fires through the vaporization of perfluorohexanone can minimize fire damage and avoid secondary damage to burning objects during the extinguishing process. Furthermore, the vaporization temperature of perfluorohexanone is lower than the LCST of temperature-sensitive materials, which is more conducive to the cooling effect of the extinguishing composition.

[0017] Preferably, the composition also includes a surfactant selected from at least one of fluorocarbon surfactants, sodium dodecylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl sulfate, hexadecyltrimethylammonium bromide, nonylphenol polyoxyethylene ether, higher carbon fatty alcohol polyoxyethylene ether, fatty acid glycerides, fatty acid sorbitan, and polyvinyl alcohol. Adding a surfactant to the fire extinguishing composition facilitates foaming, allowing the temperature-sensitive material to form a foam gel during fire extinguishing. Compared to ordinary gels, foam gels are more effective at covering large areas of the fire.

[0018] Preferably, the surfactant includes a fluorocarbon surfactant, which is a C8 type linear fluorocarbon surfactant.

[0019] Preferably, the C8 type linear fluorocarbon surfactant is selected from at least one of perfluorooctane sulfonate and perfluorooctanoic acid.

[0020] Preferably, it also includes the flame retardant ammonium polyphosphate. Introducing a flame retardant into the fire extinguishing composition can further improve the flame retardant properties of the fire extinguishing composition.

[0021] Preferably, the degree of polymerization of the flame retardant ammonium polyphosphate is 30 to 50.

[0022] According to a second aspect of the present invention, a battery system is provided, comprising a battery pack and the aforementioned fire extinguishing composition. With rapid economic development and advancements in modern science and technology, the safety requirements for lithium-ion batteries in the power battery industry are also rising. Power batteries are prone to thermal runaway, and the extinguishing temperature of the fire extinguishing composition is close to the thermal runaway temperature of the power battery. Therefore, the aforementioned fire extinguishing composition is suitable for extinguishing and cooling power batteries, and reducing the possibility of reignition. The battery system provided by the present invention, by applying the aforementioned fire extinguishing composition to the safety prevention and control of thermal runaway in power batteries, not only has a strong fire extinguishing effect but also effectively prevents the battery pack from reigniting. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions of this invention, 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 embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0024] Example 1

[0025] This embodiment provides a fire extinguishing composition comprising a fire extinguishing agent, a temperature-sensitive material, a surfactant, and a flame retardant. The specific preparation method of the fire extinguishing composition is as follows: Fire extinguishing agent and temperature-sensitive material are taken according to the mass ratio, and surfactant and flame retardant are added; the mixture is thoroughly stirred to obtain the fire extinguishing composition.

[0026] The mass ratio of extinguishing agent to temperature-sensitive material is 1:2. Perfluorohexanone is selected as the extinguishing agent, a 5wt% aqueous solution of hydrogel polymer is selected as the temperature-sensitive material, perfluorooctane sulfonate, a C8 type linear fluorocarbon surfactant, is selected as the surfactant, and ammonium polyphosphate with a degree of polymerization of 40 is selected as the flame retardant.

[0027] The above-mentioned hydrogel polymer is an N-isopropylacrylamide hydrogel polymer modified with acrylic acid. According to the test, the lower critical solution temperature of the hydrogel polymer is 85℃, the number average molecular weight is 400,000 Daltons, and the viscosity of the hydrogel polymer is 4820 mPa·s at 95℃ and 615 mPa·s at 55℃.

[0028] The specific preparation method of hydrogel polymer is as follows:

[0029] S1. Prepare an aqueous solution of sodium acrylate with a pH of 7.0, wherein the sodium acrylate content in the aqueous solution is 10 wt%.

[0030] S2. Dissolve N-isopropylacrylamide in water to prepare an aqueous solution of N-isopropylacrylamide, wherein the content of N-isopropylacrylamide in the aqueous solution of N-isopropylacrylamide is 10 wt%;

[0031] S3. Take sodium acrylate aqueous solution and N-isopropylacrylamide aqueous solution according to the mass ratio of sodium acrylate: N-isopropylacrylamide = 1.3: 8. Then, under the protection of nitrogen, add sodium acrylate aqueous solution, crosslinking agent N,N-methylenebisacrylamide, initiator ammonium persulfate, and crosslinking promoter N,N,N',N'-tetramethylethylenediamine to N-isopropylacrylamide aqueous solution and mix well to obtain the reaction base solution.

[0032] S4. Heat the reaction base liquid to 85°C, keep it at that temperature for 5 hours, filter, wash, and dry to obtain the hydrogel polymer.

[0033] In this embodiment, the amount and / or type of surfactant, flame retardant, crosslinking agent, initiator, and crosslinking accelerator can be adjusted according to the actual situation.

[0034] Example 2

[0035] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that in the process of preparing the fire extinguishing composition, the mass ratio of the fire extinguishing agent to the temperature-sensitive material is 1:5, and the other raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0036] Example 3

[0037] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that in the process of preparing the fire extinguishing composition, the mass ratio of fire extinguishing agent to temperature-sensitive material is 2:1, and the other raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0038] Example 4

[0039] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that in the preparation of the hydrogel polymer, the mass ratio of sodium acrylate to N-isopropylacrylamide is 1.3:3, so that the lower critical dissolution temperature of the obtained hydrogel polymer is 92°C. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0040] Example 5

[0041] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that in the preparation of the hydrogel polymer, the mass ratio of sodium acrylate to N-isopropylacrylamide is 1.3:5, so that the lower critical dissolution temperature of the obtained hydrogel polymer is 90°C. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0042] Example 6

[0043] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that in the preparation of the hydrogel polymer, the mass ratio of sodium acrylate to N-isopropylacrylamide is 1.3:12, so that the lower critical dissolution temperature of the obtained hydrogel polymer is 70°C. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0044] Example 7

[0045] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that in the preparation of the hydrogel polymer, the mass ratio of sodium acrylate to N-isopropylacrylamide is 1.3:15, so that the lower critical dissolution temperature of the obtained hydrogel polymer is 45°C. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0046] Example 8

[0047] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that a 0.5 wt% hydrogel polymer aqueous solution is used as the temperature-sensitive material in the preparation of the fire extinguishing composition. This results in the temperature-sensitive material having a viscosity of 4620 mPa·s at 95°C and 530 mPa·s at 55°C. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0048] Example 9

[0049] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that a 2.5 wt% hydrogel polymer aqueous solution is used as the temperature-sensitive material in the preparation of the fire extinguishing composition, so that the viscosity of the temperature-sensitive material is 4775 mPa·s at 95°C and 585 mPa·s at 55°C. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0050] Example 10

[0051] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that ethyl nonafluoroisobutyl ether is used as the fire extinguishing agent in the preparation of the fire extinguishing composition. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0052] Example 11

[0053] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that a mixture of perfluorohexanone and ethyl nonafluoroisobutyl ether is used as the fire extinguishing agent in the preparation of the fire extinguishing composition. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0054] Example 12

[0055] This embodiment refers to the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this embodiment and Example 1 is that the addition of surfactant is omitted in the preparation of the fire extinguishing composition. The remaining raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0056] Comparative Example 1

[0057] This comparative example uses the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this comparative example and Example 1 is that an equal mass of water is used instead of the temperature-sensitive material used in Example 1 during the preparation of the fire extinguishing composition. The remaining raw material ratios and preparation methods are strictly consistent with those of Example 1.

[0058] Comparative Example 2

[0059] This comparative example uses the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this comparative example and Example 1 is that an equal mass of silica gel is used instead of the temperature-sensitive material used in Example 1 during the preparation of the fire extinguishing composition. The remaining raw material ratios and preparation methods are strictly consistent with those of Example 1.

[0060] Comparative Example 3

[0061] This comparative example uses the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this comparative example and Example 1 is that in the process of preparing the fire extinguishing composition, the mass ratio of the fire extinguishing agent to the temperature-sensitive material is 0.7:5, while the other raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0062] Comparative Example 4

[0063] This comparative example uses the preparation method provided in Example 1 to prepare a fire extinguishing composition. The difference between this comparative example and Example 1 is that in the process of preparing the fire extinguishing composition, the mass ratio of the fire extinguishing agent to the temperature-sensitive material is 12:5, while the other raw material ratios and preparation methods are strictly consistent with those in Example 1.

[0064] Test case

[0065] Test subjects: Fire extinguishing compositions provided in Examples 1-11 and Comparative Examples 1-4.

[0066] Test items and test methods:

[0067] (1) Detection of the Low Critical Solution Temperature (LCST) of the temperature-sensitive material: The sample was prepared as a 1% aqueous solution, and a small amount was dropped into the sample cell of an aluminum crucible, weighed, and sealed. A Mettler DSC6230 differential scanning calorimeter was used, and under N2 protection, the temperature was increased from 15℃ to 100℃ at a heating rate of 3℃ / min. The relationship curve between the DSC reversible enthalpy change and temperature was obtained, and the peak temperature of this curve was defined as the LCST of the sample.

[0068] (2) Viscosity test of temperature-sensitive materials: The temperature-sensitive materials in each test object were tested using a viscometer. The viscosity of the temperature-sensitive materials at 55℃ and 95℃ was tested respectively. Each sample was measured 3 times and the average value was taken.

[0069] (3) Fire extinguishing performance test of the fire extinguishing composition: Fire extinguishing compositions for each test object were prepared by containing the fire extinguishing composition in a heat-conducting component. The lithium battery and heating device were fixed on the stand using a fixing clamp. The fire extinguishing composition was fixed 2 cm away from the top surface of the lithium battery. The heating device was started to heat the lithium battery until thermal runaway occurred and open flame appeared. The battery safety valve opened and the heating device was turned off. The time from the spraying of the fire extinguishing composition to the extinguishing of the flame (no open flame) was measured, and it was checked whether there was a gel film formed by a temperature-sensitive material on the surface of the battery. The observation was continued for 30 minutes to check whether reignition occurred.

[0070] The heating device has a power of 400W. The lithium battery is a square aluminum-cased ternary lithium-ion battery with lithium nickel cobalt manganese oxide [Li(NiCoMn)O2] as the positive electrode material. The rated capacity is 150A·h, the mass of a single battery cell is 2700±2.3g, and the dimensions of a single lithium-ion battery cell are 150mm×105mm×80mm. The state of charge (SOC) of all experimental batteries is 100%.

[0071] Test results: The raw material group allocation of each test subject is shown in Table 1, and the specific test data is shown in Table 2.

[0072] Table 1. Raw material composition ratios used for each test subject

[0073]

[0074] Note: In the table above, NIPA refers to N-isopropylacrylamide, SA refers to sodium acrylate, and surfactants are omitted from the raw materials of Example 11.

[0075] Table 2. Test performance of each test subject

[0076]

[0077] Results analysis:

[0078] The fire extinguishing compositions provided in Examples 1-12 were compared with those provided in Comparative Examples 1-4. As shown in Table 2, compared with the test performance of Comparative Examples 1-4 and Examples 4 and 7, the fire extinguishing compositions used in the other examples had shorter fire extinguishing time and were less likely to reignite the fire source.

[0079] In Comparative Examples 1 and 2, no temperature-sensitive material was used in the fire extinguishing compositions. Comparative Example 1 used liquid water, and Comparative Example 2 used a gel-like silicone gel. Comparing the test results of Comparative Examples 1 and 2 with those of Examples 1 to 12, it can be found that the fire extinguishing compositions of Examples 1 to 12 can effectively control the fire, slow its spread, and prevent reignition, thereby achieving the goal of completely extinguishing the flames. This demonstrates that using temperature-sensitive materials to prepare the fire extinguishing composition facilitates the release of liquid temperature-sensitive materials onto the surface of high-temperature heat sources, whereupon the temperature-sensitive materials absorb heat and transform into a gel-like state. The gel-like temperature-sensitive material can adhere to the surface of the high-temperature heat source, reducing its temperature through heat transfer. It not only further absorbs heat but also forms a non-slip heat-dissipating fire-resistant layer on the surface of the high-temperature heat source, effectively isolating the air from direct contact with the high-temperature heat source and achieving the purpose of fire isolation and preventing reignition.

[0080] Comparing the test results of Examples 1-12 with those of Comparative Examples 3-4, it can be seen that the fire extinguishing compositions of Examples 1-12 have better fire extinguishing performance and reignition prevention performance compared to the fire extinguishing compositions of Comparative Examples 3-4. They also require less time to extinguish the fire and are less prone to reignition. This demonstrates that when the mass ratio of the fire extinguishing agent to the temperature-sensitive material falls within the range of 1-10:5, the resulting fire extinguishing composition can possess both excellent fire extinguishing performance and reignition prevention performance.

[0081] Comparing the test results of Examples 1 and 4-7 in Table 2, it can be found that as the proportion of sodium acrylate in the raw materials for preparing the hydrogel polymer increases, the lower critical dissolution temperature of the temperature-sensitive material also increases. The fire extinguishing compositions provided in Examples 1, 5, and 6 exhibit better anti-reignition performance, indicating that when the viscosity of the temperature-sensitive material used is ≥4000 mPa·s above 95°C and ≤1000 mPa·s below 55°C, the resulting fire extinguishing composition can effectively prevent reignition.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A fire extinguishing composition characterised in that, The fire extinguishing agent and the temperature-sensitive material are included; The fire extinguishing agent is a fluorine-based fire extinguishing agent with fluorine-containing active groups; The temperature-sensitive material includes a hydrogel polymer, and the hydrogel polymer is an N-isopropyl acrylamide hydrogel polymer and / or a modified product thereof; The fire extinguishing agent: the temperature-sensitive material = 1-10:5 by mass; The lower critical solution temperature of the hydrogel polymer is above 70℃.

2. The fire extinguishing composition of claim 1, wherein, The temperature-sensitive material is an aqueous solution of the hydrogel polymer, and the concentration of the hydrogel polymer in the temperature-sensitive material is not less than 0.5 wt%; The temperature-sensitive material satisfies the following conditions: the viscosity of the temperature-sensitive material is ≥4000 mPa·s at above 95℃; and the viscosity of the temperature-sensitive material is ≤1000 mPa·s at below 55℃.

3. The fire extinguishing composition according to any one of claims 1 to 2, wherein The hydrogel polymer is an acrylic modified N-isopropyl acrylamide hydrogel polymer, and the preparation of the acrylic modified N-isopropyl acrylamide hydrogel polymer includes the following steps: S1. An aqueous sodium acrylate solution with a pH of 6.5-7.5 is prepared, and the content of sodium acrylate in the aqueous sodium acrylate solution is 5 wt%-15 wt%; S2. N-isopropyl acrylamide is dissolved in water to prepare an N-isopropyl acrylamide aqueous solution, and the content of N-isopropyl acrylamide in the N-isopropyl acrylamide aqueous solution is 5 wt%-15 wt%; S3. The aqueous sodium acrylate solution and the N-isopropyl acrylamide aqueous solution are taken in a mass ratio of the aqueous sodium acrylate: the N-isopropyl acrylamide = 1.3:(5-12), and then the N-isopropyl acrylamide aqueous solution is added with the aqueous sodium acrylate solution, a crosslinking agent, an initiator, and a crosslinking promoter under the protection of an inert atmosphere, and mixed uniformly to obtain a reaction bottom liquid; S4. The reaction bottom liquid is heated to a temperature of 75-95℃, and incubated to prepare the hydrogel polymer.

4. The fire extinguishing composition of claim 3, wherein: The number average molecular weight of the hydrogel polymer is 250-500 million Daltons.

5. The fire extinguishing composition of claim 1 wherein, The fluorine-based fire extinguishing agent includes at least one of perfluorohexanone, perfluorobutyl methyl ether, methyl nonafluorobutyl ether, ethyl nonafluoroisobutyl ether, pentafluorobutane, and decafluoro-3-methoxy 4-(trifluoromethyl)-pentane.

6. The fire extinguishing composition of claim 1, wherein A surfactant is further included, and the surfactant includes at least one of a fluorocarbon surfactant, sodium dodecylbenzenesulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium lauryl sulfate, cetyltrimethylammonium bromide, nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, fatty acid glyceride, fatty acid sorbitan, and polyvinyl alcohol.

7. The fire extinguishing composition of claim 6 wherein: The surfactant includes the fluorocarbon surfactant, and the fluorocarbon surfactant includes a C8 linear fluorocarbon surfactant.

8. The fire extinguishing composition of claim 1 wherein, An ammonium polyphosphate fire retardant is further included.

9. A battery system characterized by, The battery system includes a battery pack and the fire extinguishing composition according to any one of claims 1-6.

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