Quantum dot catalytic cold flame conversion fire extinguishing agent

Abstract

The invention discloses a quantum dot catalytic cold flame conversion fire extinguishing agent which is composed of a component A and a component B. The component A comprises a shell and a cooling inner core wrapped in the shell, and the shell is broken when the external environment reaches the preset starting temperature to release the cooling inner core in the shell; wherein a component A of the fire extinguishing agent is a high-temperature quantum dot microcapsule, a component B of the fire extinguishing agent is a fire extinguishing agent base material I, and the mass ratio of the high-temperature quantum dot microcapsule to the fire extinguishing agent base material I is 75-80%: 20-25%; or the component A of the fire extinguishing agent is the low-temperature quantum dot microcapsule, the component B of the fire extinguishing agent is the fire extinguishing agent base material II, and the mass ratio of the low-temperature quantum dot microcapsule to the fire extinguishing agent base material is (70-75%): (25-30%). According to the present invention, the high-temperature type fire extinguishing agent and the low-temperature type fire extinguishing agent are included, the high-temperature type quantum dot microcapsule and the low-temperature type quantum dot microcapsule are adopted to perform cooling, such that the secondary re-combustion of the battery can be effectively prevented, the CO concentration and the H2 concentration during the combustion can be reduced, and the explosion risk can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of fire fighting technology, and in particular to a quantum dot catalytic cold flame conversion fire extinguishing agent. Background Art

[0002] With the widespread application of new energy batteries (such as lithium batteries), fire accidents caused by lithium batteries in electric vehicles and energy storage power stations occur frequently. Efficient fire extinguishing technology is one of the key means to ensure the safe application of lithium batteries.

[0003] Thermal runaway is a key issue in lithium battery safety research. The key cause of lithium battery fires is thermal runaway inside the battery cell. Local high temperature stimulates internal thermal decomposition reactions, which then spread to adjacent batteries to produce a chain exothermic reaction, causing the fire to spread.

[0004] Traditional fire extinguishing agents (such as perfluorohexanone and dry powder fire extinguishing agents) mainly extinguish fires by physically cooling or isolating oxygen, but they cannot effectively suppress the chain exothermic reaction inside lithium batteries, resulting in a high re-ignition rate. In addition, when lithium battery electrolytes burn, they produce large amounts of flammable gases such as CO and H2. Traditional fire extinguishing agents cannot catalyze their conversion. The high concentrations of CO and H2 still pose an explosion risk.

[0005] According to existing research, rapid cooling of lithium batteries is an effective method to suppress their re-ignition. Patent application number CN202311454345.X discloses a low-boiling-point slow-release cooling fire extinguishing agent, its preparation method, and application. This fire extinguishing agent can achieve ultra-low temperature cooling, has a good cooling effect, and can effectively suppress thermal runaway and re-ignition problems of lithium batteries. However, it cannot convert combustible gases and poses an explosion risk.

[0006] Patent application number CN201710793550.7 discloses a microcapsule automatic fire extinguishing agent. The agent comprises a primary fire extinguishing material, a microcapsule coating material, and auxiliary materials. It integrates detection, control, activation, and fire extinguishing functions, enabling automatic fire extinguishing. However, the agent lacks a cooling effect, resulting in a high re-ignition rate.

[0007] Therefore, in order to solve the above problems, the present application proposes a quantum dot catalytic cold flame conversion fire extinguishing agent. Summary of the Invention

[0008] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide a quantum dot catalytic cold flame conversion fire extinguishing agent.

[0009] The present invention provides a quantum dot catalytic cold flame conversion fire extinguishing agent, which is composed of component A and component B. Component A includes an outer shell and a cooling inner core wrapped in the outer shell. When the external environment reaches a predetermined starting temperature, the outer shell ruptures to release the cooling inner core inside.

[0010] The fire extinguishing agent comprises a high-temperature quantum dot microcapsule as component A and a fire extinguishing agent base material 1 as component B. The mass ratio of the high-temperature quantum dot microcapsule to the fire extinguishing agent base material 1 is 75-80%:20-25%, and is used for cooling and extinguishing fires in high-temperature environments greater than 500°C; or

[0011] Component A of the fire extinguishing agent is low-temperature quantum dot microcapsules, and component B is a second fire extinguishing agent substrate. The mass ratio of the low-temperature quantum dot microcapsules to the fire extinguishing agent substrate is 70-75%:25-30%, and it is used to cool down and extinguish fires in low-temperature environments of >150°C and <350°C.

[0012] Furthermore, the preparation method of the high-temperature quantum dot microcapsules comprises the following steps:

[0013] 1) Preparing rare earth element-doped core-shell quantum dots;

[0014] 2) Rare earth element-doped core-shell quantum dots are mixed with an amino-modified PLGA solution, and high-temperature quantum dot microcapsules are prepared by electrostatic spraying. The shell material of the high-temperature quantum dot microcapsules is PLGA, and the cooling core material is rare earth element-doped core-shell quantum dots. The particle size of the high-temperature quantum dot microcapsules is 10-25 μm.

[0015] Furthermore, the core-shell structure quantum dots include a CeO2 core and a MoS2 shell; and the preparation method of the rare earth element-doped core-shell structure quantum dots includes the following steps:

[0016] 1) dissolving cerium nitrate and citric acid in ethanol at a molar ratio of 1:2, stirring until gelation occurs, and calcining at 500° C. for 2 hours to obtain CeO2 nanoparticles having a particle size of 2-3 nm;

[0017] 2) CeO2 nanoparticles, sodium molybdate, and thiourea are mixed in a solvent at a molar ratio of 1:1:3, rare earth elements are added, and a hydrothermal reaction is carried out at 200°C for 12 hours. The mixture is filtered, washed, and dried to obtain rare earth element-doped core-shell quantum dots, wherein the particle size of the core-shell quantum dots nanoparticles is 7-9 nm.

[0018] Furthermore, the fire extinguishing agent substrate includes ammonium dihydrogen phosphate, magnesium sulfate and silicone oil, and the method for preparing the fire extinguishing agent from the high-temperature quantum dot microcapsules and the fire extinguishing agent substrate includes the following steps:

[0019] 1) adding ammonium dihydrogen phosphate, magnesium sulfate, and high-temperature quantum dot microcapsules in proportion to a ball mill and grinding them to obtain a mixed powder;

[0020] 2) The mixed powder is transferred to a granulator, silicone oil is added by spraying, the silicone oil acts as a binder to wet the surface of the mixed powder particles, and pressure is applied to produce fire extinguishing particles;

[0021] 3) drying the fire extinguishing particles at 60° C. for 2 hours to remove residual solvent, and encapsulating the particles in moisture-proof packaging; wherein the mass ratio of the ammonium dihydrogen phosphate, magnesium sulfate, silicone oil, and high-temperature quantum dot microcapsules is 50-52%: 20-22%: 5-6%: 20-25%;

[0022] Furthermore, the rare earth element is one or a composite of two components of La and Ce.

[0023] Furthermore, the preparation method of the low-temperature quantum dot microcapsules comprises the following steps:

[0024] 1) Preparing CuGaS2 quantum dots;

[0025] 2) mixing CuGaS2 quantum dots, oleylamine, and a compound containing a carboxyl group, introducing a carboxyl group by oleylamine ligand exchange to obtain surface hydroxylated CuGaS2 quantum dots;

[0026] 3) placing the phosphate flame retardant and the surface hydroxylated CuGaS2 quantum dots in a solvent in proportion to react to obtain a complex of the phosphate flame retardant and the surface hydroxylated CuGaS2 quantum dots;

[0027] 4) placing the complex obtained in step 3) in a solvent to obtain a CuGaS2 quantum dot dispersion;

[0028] 5) The CuGaS2 quantum dot dispersion is mixed with a surfactant, a porous silica gel carrier, and a PNIPAM prepolymer, and a low-temperature quantum dot microcapsule is generated by microfluidic technology. The shell material of the low-temperature quantum dot microcapsule is PNIPAM, and the cooling core material of the low-temperature quantum dot microcapsule is CuGaS2 quantum dots. The particle size of the low-temperature quantum dot microcapsule is 5-20 μm.

[0029] Furthermore, the preparation method of the CuGaS2 quantum dot dispersion comprises the following steps:

[0030] Cuprous chloride, gallium chloride, and thioacetamide were mixed in a molar ratio of 1:1:2, reacted at 220° C. for 25 minutes, and purified to obtain CuGaS 2 quantum dots, the particle size of which was 8-10 nm.

[0031] Furthermore, the second fire extinguishing agent substrate includes an endothermic agent and an inert gas, and the method for preparing a fire extinguishing agent from the low-temperature quantum dot microcapsules and the second fire extinguishing agent substrate includes the following steps:

[0032] The heat absorbent, inert gas and low-temperature quantum dot microcapsules are mixed homogeneously in proportion under high pressure and filled into a fire extinguishing tank. The mass ratio of the heat absorbent, inert gas and low-temperature quantum dot microcapsules is 67-70%: 3-5%: 25-30%.

[0033] Furthermore, the surfactant is one of perfluoropolyether, short-chain fluorocarbon surfactant, silicone surfactant, and bio-based surfactant.

[0034] Furthermore, the heat absorbent is one of perfluorohexanone, monobromotrifluoropropylene, and heptafluoropropane; and the inert gas is one of nitrogen and argon.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The fire extinguishing agent of the present invention significantly enhances the cooling performance of the fire extinguishing agent, converting high-temperature combustion into low-temperature combustion, reducing heat release, and effectively suppressing battery thermal runaway and secondary re-ignition problems;

[0037] (2) The present application also reduces the concentration of combustible gases CO and H2, thereby reducing the risk of explosion; and the present application can also inhibit the spread of heat when the lithium-ion battery catches fire, thereby blocking the occurrence of a chain reaction.

[0038] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below in conjunction with the embodiments. It will be appreciated that the specific embodiments described herein are intended only to explain the invention and are not intended to limit the invention. It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the embodiments.

[0040] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to and in combination with the embodiments.

[0041] The present application provides a quantum dot catalytic cold flame conversion fire extinguishing agent, which is composed of component A and component B. Component A includes an outer shell and a cooling inner core wrapped in the outer shell. When the external environment reaches a predetermined starting temperature, the outer shell ruptures to release the cooling inner core inside.

[0042] The fire extinguishing agent's component A is a high-temperature quantum dot microcapsule, and component B is a fire extinguishing agent base material. The mass ratio of the high-temperature quantum dot microcapsule to the fire extinguishing agent base material is 75-80%:20-25%. It is used to cool down and extinguish fires in high-temperature environments greater than 500°C; or,

[0043] Component A of the fire extinguishing agent is low-temperature quantum dot microcapsules, and component B is the second fire extinguishing agent base material. The mass ratio of the low-temperature quantum dot microcapsules to the fire extinguishing agent base material is 70-75%:25-30%. It is used to cool down and extinguish fires in low-temperature environments of >150°C and <350°C.

[0044] Specifically, high-temperature quantum dot microcapsules and fire extinguishing agent substrate 1 form a high-temperature fire extinguishing agent, which can convert high-temperature combustion (>500°C) into low-temperature combustion and reduce the content of CO and H2 combustible gases; low-temperature quantum dot microcapsules and fire extinguishing agent substrate 2 form a low-temperature fire extinguishing agent, which can convert low-temperature combustion (150-300°C) into low-temperature combustion and reduce the content of CO and H2 combustible gases.

[0045] In the high-temperature fire extinguishing agent, the preparation method of high-temperature quantum dot microcapsules includes the following steps:

[0046] S100: preparing rare earth element-doped core-shell structure quantum dots;

[0047] S200: Rare earth element-doped core-shell structure quantum dots are mixed with amino-modified PLGA solution, and high-temperature quantum dot microcapsules are prepared by electrostatic spraying. The shell material of the high-temperature quantum dot microcapsules is PLGA, and the cooling core material is rare earth element-doped core-shell structure quantum dots. The particle size of the high-temperature quantum dot microcapsules is 10-25μm.

[0048] Specifically, poly(lactic-co-glycolic acid) (PLGA) is a commonly used biodegradable polymer. Under high temperature conditions, PLGA can maintain a relatively stable structure and serve as a carrier for core-shell quantum dots. The amino modification provides sites for chemical reactions with active groups (such as carboxyl and hydroxyl groups) on the surface of the core-shell quantum dots, firmly fixing the core-shell quantum dots within the microcapsule through chemical bonding, thereby improving the stability of the microcapsule and the loading efficiency of the core-shell quantum dots.

[0049] The specific steps are as follows: adding core-shell structure quantum dots to PLGA solution, ultrasonically dispersing for 45 minutes to uniformly disperse the core-shell structure quantum dots in the solution, loading the prepared mixed solution into a syringe, and delivering the solution to the nozzle at a certain flow rate through a syringe pump. Under the action of a high-voltage electrostatic field, the solution is ejected from the nozzle and atomized to form charged droplets, which move toward the receiving electrode under the action of the electric field force. During the movement, the solvent in the droplets gradually evaporates, and finally forms a high-temperature quantum dot microcapsule with a particle size of 15 μm on the receiving electrode; the shell material of the high-temperature quantum dot microcapsule is PLGA, and the cooling core material is core-shell structure quantum dots doped with rare earth elements. The shell ruptures under an environment of >500°C, releasing the core-shell structure quantum dots doped with rare earth elements.

[0050] Preferably, the core-shell structure quantum dots include a CeO2 core and a MoS2 shell; and the preparation method of the core-shell structure quantum dots doped with rare earth elements includes the following steps:

[0051] S101: dissolving cerium nitrate and citric acid in ethanol at a molar ratio of 1:2, stirring at 80°C until gelation, and calcining at 500°C for 2 hours to obtain CeO2 nanoparticles. The particle size of the CeO2 nanoparticles is 2-3 nm.

[0052] Specifically, CeO2 nanoparticles with a particle size of 2-3 nm were prepared by a sol-gel method;

[0053] S102: CeO2 nanoparticles, sodium molybdate, and thiourea are mixed in a solvent at a molar ratio of 1:1:3, rare earth elements are added, and a hydrothermal reaction is carried out at 200°C for 12 hours. The mixture is filtered, washed, and dried to obtain rare earth element-doped core-shell structured quantum dots. The particle size of the nanoparticles of the core-shell structured quantum dots is 7-9 nm.

[0054] Preferably, a composite of one or two components of the rare earth elements La and Ce;

[0055] Specifically, a hydrothermal method is used to obtain core-shell quantum dots with MoS2 shells encapsulating CeO2 nanoparticles. The core-shell quantum dots and salt compounds containing rare elements La or Ce are added to a solvent and hydrothermally reacted at 100°C for 10 hours. After filtration, washing, and drying, La-doped nanoparticles are obtained. 3+ / Ce 4+ core-shell structured quantum dots.

[0056] Preferably, the fire extinguishing agent substrate comprises ammonium dihydrogen phosphate, magnesium sulfate and silicone oil; and the method for preparing the fire extinguishing agent from the high-temperature quantum dot microcapsules and the fire extinguishing agent substrate comprises the following steps:

[0057] S100: adding ammonium dihydrogen phosphate, magnesium sulfate, and high-temperature quantum dot microcapsules in proportion to a ball mill and grinding them to obtain a mixed powder;

[0058] S200: The mixed powder is transferred to a granulator, silicone oil is added by spraying, the silicone oil acts as a binder to wet the surface of the mixed powder particles, and pressure is applied to produce fire extinguishing particles;

[0059] S300: Dry the fire extinguishing pellets at 60°C for 2 hours to remove any residual solvent, then package them in moisture-proof packaging. The mass ratio of ammonium dihydrogen phosphate, magnesium sulfate, silicone oil, and high-temperature quantum dot microcapsules is 50-52%: 20-22%: 5-6%: 20-25%.

[0060] In the low-temperature fire extinguishing agent, the preparation method of low-temperature quantum dot microcapsules includes the following steps:

[0061] S100: CuGaS2 quantum dots are prepared;

[0062] S200: mixing CuGaS2 quantum dots, oleylamine and a compound containing a carboxyl group, introducing a carboxyl group by oleylamine ligand exchange to obtain surface hydroxylated CuGaS2 quantum dots;

[0063] Specifically, the hydroxyl groups chemically bond with the surface of CuGaS2 quantum dots to form a stable chemical structure.

[0064] S300: placing a phosphate flame retardant and surface hydroxylated CuGaS2 quantum dots in a solvent in a certain proportion to react, thereby obtaining a complex of the phosphate flame retardant and the surface hydroxylated CuGaS2 quantum dots;

[0065] S400: placing the complex obtained in step S300 in a solvent to obtain a CuGaS2 quantum dot dispersion;

[0066] S500: Mix the CuGaS2 quantum dot dispersion with a surfactant, a porous silica gel carrier, and a PNIPAM prepolymer, and generate low-temperature quantum dot microcapsules through microfluidic technology. The shell material of the low-temperature quantum dot microcapsule is PNIPAM, and the cooling core material of the low-temperature quantum dot microcapsule is CuGaS2 quantum dots. The particle size of the low-temperature quantum dot microcapsule is 5-20μm.

[0067] Preferably, the method for preparing the CuGaS2 quantum dot dispersion in step S100 comprises the following steps:

[0068] S101: Cuprous chloride, gallium chloride, and thioacetamide are mixed in a molar ratio of 1:1:2, reacted at 220° C. for 25 minutes, and CuGaS 2 quantum dots are obtained after purification. The particle size of the CuGaS 2 quantum dots is 8-10 nm.

[0069] Preferably, the second fire extinguishing agent substrate includes an endothermic agent and an inert gas, and the method for preparing a fire extinguishing agent from the low-temperature quantum dot microcapsules and the second fire extinguishing agent substrate includes the following steps:

[0070] S100: The heat absorber, inert gas and low-temperature quantum dot microcapsules are mixed homogeneously in proportion under high pressure and filled into a fire extinguisher tank. The mass ratio of the heat absorber, inert gas and low-temperature quantum dot microcapsules is 67-70%: 3-5%: 25-30%.

[0071] Preferably, the surfactant is one of perfluoropolyether, short-chain fluorocarbon surfactant, silicone surfactant, and bio-based surfactant.

[0072] Preferably, the heat absorbent is one of perfluorohexanone, monobromotrifluoropropylene, and heptafluoropropane; and the inert gas is one of nitrogen and argon.

[0073] Example 1

[0074] A quantum dot catalytic cold flame conversion fire extinguishing agent, comprising component A and component B, wherein component A is a high-temperature quantum dot microcapsule and component B is a fire extinguishing agent substrate. The high-temperature fire extinguishing agent is composed of a specific preparation method comprising the following steps:

[0075] S100: Cerium nitrate and citric acid were dissolved in ethanol at a molar ratio of 1:2, stirred at 80°C until gelation, and calcined at 500°C for 2 hours to obtain CeO2 nanoparticles. The particle size of the CeO2 nanoparticles was 2-3 nm.

[0076] S200: CeO2 nanoparticles, sodium molybdate, and thiourea are mixed in a solvent at a molar ratio of 1:1:3, and a salt compound containing the rare element La is added. The mixture is hydrothermally reacted at 200°C for 12 hours, and then filtered, washed, and dried to obtain La-doped nanoparticles. 3+ The core-shell structure quantum dots have a particle size of 9 nm.

[0077] S300: The La-doped 3+ The core-shell structure quantum dots were mixed with amino-modified PLGA solution, and high-temperature quantum dot microcapsules with a particle size of 20 μm were prepared by electrostatic spraying.

[0078] S400: adding ammonium dihydrogen phosphate, magnesium sulfate, and high-temperature quantum dot microcapsules in a ball mill according to a mass ratio and grinding them to obtain a mixed powder;

[0079] S500: The mixed powder is transferred to a granulator, silicone oil is added by spraying, and the silicone oil acts as a binder to wet the surface of the mixed powder particles, and pressure is applied to produce fire extinguishing particles; the mass ratio of ammonium dihydrogen phosphate, magnesium sulfate, silicone oil and high-temperature quantum dot microcapsules is 52%:22%:5%:21%.

[0080] S600: Dry the fire extinguishing particles at 60°C for 2 hours to remove residual solvent, and package them in moisture-proof packaging to obtain a high-temperature fire extinguishing agent.

[0081] Example 2:

[0082] The difference from Example 1 is that the mass ratios of ammonium dihydrogen phosphate, magnesium sulfate, silicone oil and high-temperature quantum dot microcapsules are different. The other steps are the same as those in Example 1 and will not be repeated here.

[0083] The mass ratio of ammonium dihydrogen phosphate, magnesium sulfate, silicone oil and high-temperature quantum dot microcapsules in this embodiment is 50%:22%:5%:23%.

[0084] Example 3:

[0085] The difference from Example 1 is that the mass ratios of ammonium dihydrogen phosphate, magnesium sulfate, silicone oil and high-temperature quantum dot microcapsules are different. The other steps are the same as those in Example 1 and will not be repeated here.

[0086] The mass ratio of ammonium dihydrogen phosphate, magnesium sulfate, silicone oil and high-temperature quantum dot microcapsules in this embodiment is 53%:22%:5%:25%.

[0087] Effect verification experiment:

[0088] A 129Ah ternary lithium-ion battery pack (24 cells connected in series) was heated to 260°C by a heating plate. When the lithium-ion battery pack thermally ran away and caught fire, the fire extinguishing agents of Examples 1, 2, and 3 or commercially available water-based fire extinguishing agents (including surfactants, flame retardants, and stabilizers) and perfluoroacetone fire extinguishing agents (including perfluoroacetone) were released to extinguish the fire. The experimental results are shown in Table 1:

[0089] Table 1 Results of high temperature fire extinguishing agent effect verification experiment

[0090]

[0091]

[0092] As shown in Table 1, the high-temperature fire extinguishing agent of the present application can significantly enhance the cooling performance of the fire extinguishing agent, so that it can be used to extinguish battery fires and effectively prevent secondary battery re-ignition; the present application also reduces the concentration of combustible gases CO and H2, reducing the risk of explosion; the present application can also inhibit the heat spread during lithium-ion battery fires and block the occurrence of chain reactions.

[0093] Example 4

[0094] A quantum dot catalytic cold flame conversion fire extinguishing agent is composed of component A and component B, wherein component A is a low-temperature quantum dot microcapsule and component B is a second fire extinguishing agent substrate; the low-temperature fire extinguishing agent is composed of the following steps:

[0095] S100: Cuprous chloride, gallium chloride, and thioacetamide were mixed in a molar ratio of 1:1:2, reacted at 220°C for 25 minutes, and purified to obtain CuGaS2 quantum dots with a particle size of 8-10 nm;

[0096] S200: CuGaS2 quantum dots, oleylamine and a compound containing a carboxyl group are mixed, and carboxyl groups are introduced by oleylamine ligand exchange to obtain surface hydroxylated CuGaS2 quantum dots;

[0097] S300: placing a phosphate flame retardant and surface hydroxylated CuGaS2 quantum dots in a solvent in a certain proportion to react, thereby obtaining a complex of the phosphate flame retardant and the surface hydroxylated CuGaS2 quantum dots;

[0098] S400: placing the composite obtained in step S300 in Example 4 in a solvent to obtain a CuGaS2 quantum dot dispersion;

[0099] S500: Mixing CuGaS2 quantum dot dispersion with surfactant, porous silica carrier, and PNIPAM prepolymer, and generating low-temperature quantum dot microcapsules with a particle size of 15 μm using microfluidics technology;

[0100] S600: Perfluorohexanone, nitrogen, and cryogenic quantum dot microcapsules are mixed in proportion under high pressure and homogenized, and then filled into a fire extinguisher tank to obtain a cryogenic fire extinguishing agent. The mass ratio of perfluorohexanone, nitrogen, and cryogenic quantum dot microcapsules is 70%:5%:25%.

[0101] Example 5

[0102] The difference from Example 4 is that the mass ratio of perfluorohexanone, nitrogen and low-temperature quantum dot microcapsules is different. The other steps are the same as those in Example 4 and will not be repeated here.

[0103] The mass ratio of perfluorohexanone, nitrogen and low-temperature quantum dot microcapsules in this embodiment is 63%:5%:27%.

[0104] Example 6

[0105] The difference from Example 4 is that the mass ratio of perfluorohexanone, nitrogen and low-temperature quantum dot microcapsules is different. The other steps are the same as those in Example 4 and will not be repeated here.

[0106] The mass ratio of perfluorohexanone, nitrogen and low-temperature quantum dot microcapsules in this embodiment is 65%:5%:30%.

[0107] Effect verification experiment:

[0108] A 50Ah lithium iron phosphate battery pack (24 cells connected in series) was heated to 230°C by a heating plate. When the lithium-ion battery pack thermally ran away and caught fire, the fire extinguishing agents of Examples 4, 5, and 6 or commercially available water-based fire extinguishing agents (including surfactants, flame retardants, and stabilizers) and perfluoroacetone fire extinguishing agents (including perfluoroacetone) were released to extinguish the fire. The experimental results are shown in Table 2:

[0109] Table 2 Results of low-temperature fire extinguishing agent effect verification experiment

[0110]

[0111]

[0112] As shown in Table 2, the high-temperature fire extinguishing agent of the present application can significantly enhance the cooling performance of the fire extinguishing agent, so that it can be used to extinguish battery fires and effectively prevent secondary re-ignition of the battery; the present application also reduces the concentration of combustible gases CO and H2, reducing the risk of explosion; the present application can also inhibit the heat spread during lithium-ion battery fires and block the occurrence of chain reactions.

[0113] In this specification, the terms "connect," "install," and "fix" should be understood broadly. For example, "connect" can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0114] Throughout this specification, terms such as "one embodiment" or "some embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0115] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A quantum dot catalytic cold flame conversion fire extinguishing agent, characterized in that: The fire extinguishing agent is composed of component A and component B, wherein component A includes an outer shell and a cooling inner core wrapped in the outer shell, and the outer shell ruptures when the external environment reaches a predetermined starting temperature, releasing the cooling inner core inside; wherein, The fire extinguishing agent comprises a high-temperature quantum dot microcapsule as component A and a fire extinguishing agent base material 1 as component B. The mass ratio of the high-temperature quantum dot microcapsule to the fire extinguishing agent base material 1 is 75-80%:20-25%, and is used for cooling and extinguishing fires in high-temperature environments greater than 500°C; or Component A of the fire extinguishing agent is low-temperature quantum dot microcapsules, and component B is a second fire extinguishing agent substrate. The mass ratio of the low-temperature quantum dot microcapsules to the fire extinguishing agent substrate is 70-75%:25-30%, and it is used to cool down and extinguish fires in low-temperature environments of >150°C and <350°C.

2. A quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 1, characterized in that: The preparation method of the high-temperature quantum dot microcapsules comprises the following steps: 1) Preparing rare earth element-doped core-shell quantum dots; 2) Rare earth element-doped core-shell quantum dots are mixed with an amino-modified PLGA solution, and high-temperature quantum dot microcapsules are prepared by electrostatic spraying. The shell material of the high-temperature quantum dot microcapsules is PLGA, and the cooling core material is rare earth element-doped core-shell quantum dots. The particle size of the high-temperature quantum dot microcapsules is 10-25 μm.

3. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 1, characterized in that: The core-shell structure quantum dots include a CeO2 core and a MoS2 shell; and the preparation method of the rare earth element-doped core-shell structure quantum dots includes the following steps: 1) dissolving cerium nitrate and citric acid in ethanol at a molar ratio of 1:2, stirring until gelation occurs, and calcining at 500° C. for 2 hours to obtain CeO2 nanoparticles having a particle size of 2-3 nm; 2) CeO2 nanoparticles, sodium molybdate, and thiourea are mixed in a solvent at a molar ratio of 1:1:3, rare earth elements are added, and a hydrothermal reaction is carried out at 200°C for 12 hours. The mixture is filtered, washed, and dried to obtain rare earth element-doped core-shell quantum dots, wherein the particle size of the core-shell quantum dots nanoparticles is 7-9 nm.

4. A quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 3, characterized in that: The fire extinguishing agent base material includes ammonium dihydrogen phosphate, magnesium sulfate and silicone oil. The method for preparing the fire extinguishing agent from the high-temperature quantum dot microcapsule and the fire extinguishing agent base material includes the following steps: 1) adding ammonium dihydrogen phosphate, magnesium sulfate, and high-temperature quantum dot microcapsules in proportion to a ball mill and grinding them to obtain a mixed powder; 2) The mixed powder is transferred to a granulator, silicone oil is added by spraying, the silicone oil acts as a binder to wet the surface of the mixed powder particles, and pressure is applied to produce fire extinguishing particles; 3) drying the fire extinguishing particles at 60° C. for 2 hours to remove residual solvent, and encapsulating the particles in a moisture-proof package; wherein the mass ratio of the ammonium dihydrogen phosphate, magnesium sulfate, silicone oil, and high-temperature quantum dot microcapsules is 50-52%: 20-22%: 5-6%: 20-25%.

5. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 2, characterized in that: The rare earth element is one of La and Ce or a composite of two components.

6. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 1, characterized in that: The preparation method of the low-temperature quantum dot microcapsules comprises the following steps: 1) Preparing CuGaS2 quantum dots; 2) mixing CuGaS2 quantum dots, oleylamine, and a compound containing a carboxyl group, introducing a carboxyl group by oleylamine ligand exchange to obtain surface hydroxylated CuGaS2 quantum dots; 3) placing the phosphate flame retardant and the surface hydroxylated CuGaS2 quantum dots in a solvent in proportion to react to obtain a complex of the phosphate flame retardant and the surface hydroxylated CuGaS2 quantum dots; 4) placing the complex obtained in step 3) in a solvent to obtain a CuGaS2 quantum dot dispersion; 5) The CuGaS2 quantum dot dispersion is mixed with a surfactant, a porous silica gel carrier, and a PNIPAM prepolymer, and a low-temperature quantum dot microcapsule is generated by microfluidic technology. The shell material of the low-temperature quantum dot microcapsule is PNIPAM, and the cooling core material of the low-temperature quantum dot microcapsule is CuGaS2 quantum dots. The particle size of the low-temperature quantum dot microcapsule is 5-20 μm.

7. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 6, characterized in that: The preparation method of the CuGaS2 quantum dot dispersion comprises the following steps: Cuprous chloride, gallium chloride, and thioacetamide were mixed in a molar ratio of 1:1:2, reacted at 220° C. for 25 minutes, and purified to obtain CuGaS 2 quantum dots, the particle size of which was 8-10 nm.

8. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 6, characterized in that: The second fire extinguishing agent substrate includes an endothermic agent and an inert gas. The method for preparing a fire extinguishing agent from the low-temperature quantum dot microcapsules and the second fire extinguishing agent substrate includes the following steps: The heat absorbent, inert gas and low-temperature quantum dot microcapsules are mixed homogeneously in proportion under high pressure and filled into a fire extinguishing tank. The mass ratio of the heat absorbent, inert gas and low-temperature quantum dot microcapsules is 67-70%: 3-5%: 25-30%.

9. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 7, characterized in that: The surfactant is one of perfluoropolyether, short-chain fluorocarbon surfactant, silicone surfactant and bio-based surfactant.

10. The quantum dot catalytic cold flame conversion fire extinguishing agent according to claim 8, characterized in that: The heat absorbent is one of perfluorohexanone, monobromotrifluoropropylene, and heptafluoropropane; and the inert gas is one of nitrogen and argon.

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