Foam extinguishing agent for new energy battery based on bionic dopamine adhesion and core-shell flame retardant synergy and preparation method of foam extinguishing agent

Abstract

The invention relates to a new energy battery foam extinguishing agent based on bionic dopamine adhesion and core-shell flame retardant synergy and a preparation method of the new energy battery foam extinguishing agent. The new energy battery foam extinguishing agent comprises L-dopamine and noradrenaline, the preparation method comprises the following steps: preparing hexaphenoxy cyclotriphosphazene (at) zinc borate core-shell microspheres; silicon carbide nanowires; the nano spring valve microcapsule is a CaO thermal expansion polymer; a Cu < 2 + > (at) ZIF-8 metal organic framework; deionized water and a borax-sodium carbonate buffer agent; the preparation method comprises the following steps: step 1, preparing core-shell microspheres; step 2, a catalytic carrier activation method; step 3, a supercritical emulsification method; the method has the advantages that a'core-shell microsphere-nano valve 'two-stage trigger structure is created for the first time, and 0.1-second-level pH transient is achieved through the nano valve and is higher than that in the prior art; the shell thickness of the core-shell microspheres is 80 + / -10 nm, the particle size of the core is 3.2 + / -0.5 [mu] m, flame retardance in different temperature sections that the shell is softened to release phosphazene at 80 DEG C and the core is melted into a ceramic layer at 600 DEG C is realized, and the problem of single-stage response failure is solved.

Description

Technical Field

[0001] This invention belongs to the field of fire protection materials technology, specifically relating to foam extinguishing agents for thermal runaway fires of new energy batteries and their preparation methods. Background Technology

[0002] The existing new energy batteries used in fire fighting have the following defects or problems:

[0003] Uncontrollable thermal spread: Thermal runaway in a single cell can trigger a chain reaction, with a propagation speed of up to 1 cell / second (Reference 1: UL9540A-2020); 2. High deep-layer reignition rate: Electrolyte seeps into porous electrodes and continues to react, with a reignition rate >40% within 72 hours (Reference 2: NFPA 855-2023). Several currently used extinguishing agents, such as perfluorohexanone, have no adhesive properties and a reignition rate >70% after gas escape; ABC dry powder damages circuit insulation during use and cannot suppress deep-layer fire sources; water-based foam flows and fails on the vertical battery surface, with a retention rate <30%.

[0004] In published patent applications, such as Chinese Invention Patent Application Publication No. CN118271481A, a solvent-resistant and high-temperature-resistant polymer, its synthesis method, and its application are disclosed. The synthesis method includes introducing perfluoropolyether fluoride into the molecular chain of a polysaccharide polymer by adding a diamino compound to obtain the solvent-resistant and high-temperature-resistant polymer. The provided solvent-resistant and high-temperature-resistant polymer has excellent anti-polarity and high-temperature foam stabilizing ability, and can be used as a foam stabilizer in foam fire extinguishing agents. It can significantly reduce the amount of polymer used in foam fire extinguishing agents, thereby effectively improving the foam performance, fire extinguishing performance, and resistance to polar solvents of foam fire extinguishing agents.

[0005] For example, Chinese invention patent application publication number CN115869578A discloses a gel protein foam extinguishing agent for extinguishing oil pool fires and its preparation method. By introducing hydrolyzed protein, a gel foam extinguishing agent with higher stability, water retention capacity and fire resistance is made.

[0006] For example, Chinese invention patent publication number CN111298357B discloses a colloidal foam extinguishing agent suitable for high-level and concealed fire sources in coal mines, with a foam stabilization time of over 100 hours. After absorbing the heat of the coal body, it forms a layer of water colloid, which plays a role in heat absorption, cooling, and oxygen isolation. Invention patent application publication number CN106861107A discloses an attapulgite gel foam extinguishing agent, which can maintain the stability of gel foam and improve extinguishing efficiency during the fire prevention and extinguishing process.

[0007] The aforementioned invention patent application solutions all fail to simultaneously meet the triple requirements of "rapid adhesion and coverage + precise blocking of chain reaction + long-lasting prevention of reignition". Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a foam fire extinguishing agent for new energy batteries based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardancy, and its preparation method.

[0009] The aforementioned ultra-fast foam fire extinguishing agent for new energy batteries, based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardancy, comprises: an adhesion precursor, a flame retardant synergist, a thermal management material, a foaming matrix, a pH triggering system, a catalyst carrier, a solvent, and a buffer. The adhesion precursor is L-dopamine + norepinephrine in a molar ratio of 1:2. The flame retardant synergist is hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres with a shell thickness of 80±10 nm and a core particle size of 3.2±0.5 μm. The silicon carbide nanowires have a diameter of 50 nm and a length of 10 μm, with a micro-explosion endothermic ΔH = -989 kJ / mol. The foaming matrix is ​​C6 fluorine surfactant (CF3(CF2)4COO-K). + This method reduces the surface tension of the extinguishing agent aqueous solution to 17.2 mN / m, significantly improving foam spreading efficiency. The pH triggering system uses nano-spring valve microcapsules, which are CaO@thermally expanding polymers: the triggering time is 0.1 seconds, and the pH changes instantaneously from 7.0 to 9.2; the catalyst support is Cu. 2+ @ZIF-8 metal-organic framework, with a 400% increase in polymerization rate; the solvent and buffer are deionized water + borax-sodium carbonate buffer, maintaining a pH value of 8.0±0.2.

[0010] Further, by mass percentage, L-dopamine + norepinephrine is 3.0-5.0%; hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres are 2.5-4.0%; silicon carbide nanowires are 0.2-0.5%; C6 fluorosurfactant is 0.3-0.8%; nano-spring valve microcapsules are 1.0-2.5%; Cu 2+ The ZIF-8 metal-organic framework is 0.5-1.2%; the balance is deionized water + borax-sodium carbonate buffer.

[0011] Further, by mass percentage: L-dopamine + norepinephrine 4.0%; hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres 3.2%; silicon carbide nanowires 0.35%; C6 fluorosurfactant 0.5%; nano-spring valve microcapsules 1.8%; Cu 2+ The ZIF-8 metal-organic framework is 0.5-1.2%; the balance is deionized water + borax-sodium carbonate buffer.

[0012] This invention also provides a method for preparing a foam fire extinguishing agent for new energy batteries based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardancy, including:

[0013] Step 1, preparation of core-shell microspheres;

[0014] Step 2, catalytic support activation method;

[0015] Step 3, supercritical emulsification method;

[0016] Step 4, freeze granulation method.

[0017] Further, step 1, the preparation of the core-shell microspheres, includes the following specific steps:

[0018] Step 1.1: The raw material for the pretreatment of zinc borate microspheres is battery-grade zinc borate (D50 = 3.2 ± 0.5 μm). A fluidized bed coating machine (Glatt GPCG-5) is used. The inlet air temperature for fluidized bed preheating is controlled at 45 ± 2℃, as temperatures > 50℃ will cause premature softening of the microsphere core and shell layers. The atomization pressure for microsphere fluidization is 0.8 Bar to ensure that the droplet size is controlled at 10-20 μm. The phosphazene spraying rate is 8 mL / min, the spraying amount per kilogram of microspheres is 120 mL, the drying time is 30 min, and the residual solvent is controlled to be <0.1%.

[0019] Step 1.2, Nano Spring Valve Loading Method:

[0020] Nano-spring valve microcapsules (CaO@thermally expandable polymer) were dispersed in 5wt% ethanol using an electrostatic adsorption method. A static voltage of -15kV was applied to induce the microcapsules to be directionally adsorbed onto the surface of core-shell microspheres. 0.1% polyvinylpyrrolidone was added to the ethanol dispersion as an anti-agglomeration agent. The humidity of the electrostatic adsorption chamber was ≤30%RH, and the adsorption rate was controlled at 92±3%. The calcium element distribution was determined by SEM-EDS.

[0021] Furthermore, the catalyst support activation method described in step 2 includes the following specific steps:

[0022] Step 2.1, MOF confined catalytic activation: A planetary ball mill (QM-3SP4) was used. The atmosphere in the ball mill jar was nitrogen, with O2 < 0.1%. The oxygen to zirconium content ratio of the zirconium balls was 5:1. If it is lower than 3:1, insufficient activation will occur. The rotation speed was 300 rpm. A rotation speed > 300 rpm will destroy the MOF structure. The ball milling time was 1.5-2 hours. Activation mechanism: The impact of ball milling causes L-dopamine molecules to embed into the ZIF-8 channels (pore size...). ), with Cu 2+ Forming a confined coordination structure.

[0023] Further, step 3, the supercritical emulsification method, includes the following specific steps:

[0024] Step 3.1, Phase sequence addition and premixing:

[0025] Deionized water and borax-sodium carbonate buffer were added to the reactor, and the pH was adjusted to 8.0±0.2.

[0026] Add C6 fluorosurfactant (CF3(CF2)4COO-K) + The temperature was controlled at 25±2℃ and the mixture was stirred at 500 rpm for 5 minutes to form a homogeneous micelle system.

[0027] Add core-shell microspheres (hexaphenoxycyclotriphosphazene@zinc borate) and nanovalve microcapsules (CaO@thermally expandable polymer), and disperse at low speed of 300 rpm for 10 minutes;

[0028] Finally, add the silicon carbide nanowires and stir at 500 rpm for 2 minutes; if the silicon carbide nanowires are added first, their high specific surface area (≥60 m²) will be achieved. 2 / g) will competitively adsorb surfactants, increasing the bubble diameter to 70μm and extending the extinguishing time to 2.5s;

[0029] Stirring speeds exceeding 600 rpm will cause damage to the nanovalve microcapsules, with a breakage rate >15%.

[0030] Temperatures exceeding 28°C will lead to a decrease in micelle stability and a 25% increase in the separation rate;

[0031] Step 3.2, Supercritical CO2 emulsification:

[0032] Supercritical CO2 emulsification is performed using a supercritical reactor with a pressure ≥50 MPa and a CO2 pressure of 40 MPa to achieve nanoscale emulsification. The temperature is controlled at 65±1℃ to maintain the supercritical state of CO2, the shear rate is 15,000 rpm, the bubble size is controlled within the range of 48±5 μm, the emulsification time is 30 min, and the particle size distribution (PDI) is <0.1. When the CO2 pressure is 40 MPa, an online laser particle size analyzer is required to monitor the PDI value in real time.

[0033] Furthermore, the cryopreservation granulation method described in step 4 includes the following specific steps:

[0034] Step 4.1, cryogenic curing, using liquid nitrogen cryogenic belt, the emulsion layer thickness is 2cm, the liquid nitrogen spray temperature is -45℃, the cooling rate is ≥15℃ / min, to prevent phase separation, and complete curing is achieved within 10min;

[0035] Step 4.2, crushing and screening: a low-temperature crusher is used. To avoid adhesion and agglomeration, the crushing temperature is controlled at -40℃. The crushing and screening adopts a double-layer vibrating screen with a screen aperture of 0.8mm / 1.2mm; particle size: 0.8-1.2mm, maintaining a balance between solubility and flowability.

[0036] Step 4.3: The vacuum drying temperature is 30℃ to prevent the heat-sensitive material from failing, the vacuum degree is -0.095MPa, and the Karl Fischer method is used to monitor the endpoint and control the moisture content to ≤0.5%.

[0037] The superior technical effects of this invention are as follows:

[0038] 1. The new energy battery foam fire extinguishing agent and its preparation method based on biomimetic dopamine adhesion and core-shell flame retardancy synergy are the first of their kind. The "core-shell microsphere-nanovalve" dual-stage triggering architecture is created: the nanovalve realizes pH transient change at the 0.1-second level, while the existing technology is >3s, which is significantly higher than the existing technology;

[0039] 2. The foam fire extinguishing agent for new energy batteries based on biomimetic dopamine adhesion and core-shell flame retardancy synergy described in this invention and its preparation method, the shell thickness of the core-shell microspheres is 80±10nm, the core particle size is 3.2±0.5μm, and the temperature-segmented flame retardancy is achieved by softening the shell at 80℃ to release phosphazene and melting the core into a ceramic layer at 600℃, thus solving the problem of single-stage response failure.

[0040] 3. The new energy battery foam fire extinguishing agent and its preparation method based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardancy described in this invention employs a revolutionary material design: hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres, which is the world's first application in a fire extinguishing agent.

[0041] 4. The foam fire extinguishing agent for new energy batteries based on biomimetic dopamine adhesion and core-shell flame retardancy synergy, and its preparation method, as described in this invention, utilizes Cu... 2+ The ZIF-8 confined catalytic system exhibits a catalytic efficiency exceeding 400% and a leaching rate below 86%.

[0042] 5. The new energy battery foam fire extinguishing agent and its preparation method based on biomimetic dopamine adhesion and core-shell flame retardancy synergy described in this invention comply with relevant Chinese environmental protection regulations: the C6 fluorine surfactant content is 0.5%, lower than the national limit of 1% in the "Key Control List"; it is free of PFOA / PFOS, asbestos, and heavy metals; and the catalyst carrier is Cu. 2+ In @ZIF-8, copper ions are confined and fixed, with a leaching amount of only 0.07 mg / L, far below the national standard limit of 1 mg / L. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the foam fire extinguishing agent preparation method described in this invention.

[0044] Figure 2 This is a schematic diagram of the phase sequence addition and premixing process of the foam fire extinguishing agent preparation method described in this invention.

[0045] Figure 3 This is a schematic diagram of the fire extinguishing mechanism of the foam fire extinguishing agent described in this invention.

[0046] Figure 4 This is a schematic diagram illustrating the blocking of the thermal runaway chain reaction of the foam fire extinguishing agent described in this invention. Detailed Implementation

[0047] To better understand the above-mentioned objectives, features, and advantages of the present invention, the technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Example

[0049] The ultra-fast foam fire extinguishing agent for new energy batteries based on biomimetic dopamine adhesion and core-shell flame retardancy synergy includes:

[0050] The components include: adhesion precursor, flame retardant synergist, thermal management material, foaming matrix, pH triggering system, catalyst carrier, solvent, and buffer. The adhesion precursor is L-dopamine + norepinephrine in a molar ratio of 1:2. The flame retardant synergist is hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres with a shell thickness of 80±10 nm and a core particle size of 3.2±0.5 μm. The silicon carbide nanowires have a diameter of 50 nm and a length of 10 μm, with a micro-explosion endothermic ΔH = -989 kJ / mol. The foaming matrix is ​​C6 fluorine surfactant (CF3(CF2)4COO-K). + The foaming matrix is ​​C6 fluorine surfactant (CF3(CF2)4COO-K). + This reduces the surface tension of the extinguishing agent aqueous solution to 17.2 mN / m, significantly improving foam spreading efficiency; the pH triggering system is a nano-spring valve microcapsule, made of CaO@thermally expanding polymer, with a triggering time of 0.1 seconds and a pH instantaneous change from 7.0 to 9.2; the catalyst support is Cu. 2+ @ZIF-8 metal-organic framework, with a 400% increase in polymerization rate; the solvent and buffer are deionized water + borax-sodium carbonate buffer, maintaining a pH of 8.0±0.2.

[0051] In one specific embodiment of the present invention, by mass percentage, L-dopamine + norepinephrine is 3.0-5.0%; hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres are 2.5-4.0%; silicon carbide nanowires are 0.2-0.5%; C6 fluorosurfactant is 0.3-0.8%; nano-spring valve microcapsules are 1.0-2.5%; Cu 2+ The ZIF-8 metal-organic framework is 0.5-1.2%; the balance is deionized water + borax-sodium carbonate buffer.

[0052] In one specific embodiment of the present invention, by mass percentage, L-dopamine + norepinephrine is 4.0%; hexaphenoxycyclotriphosphazene@zinc borate core-shell microspheres are 3.2%; silicon carbide nanowires are 3.5%; C6 fluorosurfactant is 0.5%; nano-spring valve microcapsules are 1.8%; Cu 2+ The ZIF-8 metal-organic framework is 0.5-1.2%; the balance is deionized water + borax-sodium carbonate buffer.

[0053] This invention also provides a method for preparing a foam fire extinguishing agent for new energy batteries based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardancy, such as... Figure 1 As shown, it includes:

[0054] Step 1, Preparation of core-shell microspheres:

[0055] Step 1.1: The raw material for the pretreatment of zinc borate microspheres is battery-grade zinc borate (D50 = 3.2 ± 0.5 μm). A fluidized bed coating machine (Glatt GPCG-5) is used. The inlet air temperature for fluidized bed preheating is controlled at 45 ± 2℃. Temperatures > 50℃ will cause premature softening of the microsphere core and shell layers. The atomization pressure for microsphere fluidization is 0.8 Bar to ensure that the droplet size is controlled at 10-20 μm. The phosphazene spraying rate is 8 mL / min, the spraying amount per kilogram of microspheres is 120 mL, the drying time is 30 min, and the residual solvent is controlled to be less than 0.1%.

[0056] Step 1.2, Nano Spring Valve Loading Method:

[0057] Nano-spring valve microcapsules (CaO@thermally expandable polymer) were dispersed in 5wt% ethanol using electrostatic adsorption. A static voltage of -15kV was applied to induce the microcapsules to be directionally adsorbed onto the surface of core-shell microspheres. 0.1% polyvinylpyrrolidone was added to the ethanol dispersion as an anti-agglomeration agent. The humidity in the electrostatic adsorption chamber was ≤30%RH, and the adsorption rate was controlled at 92±3%. The calcium element distribution was determined by SEM-EDS.

[0058] Step 2, Activation method of catalyst support:

[0059] Step 2.1, MOF confined catalytic activation, using a planetary ball mill (QM-3SP4), with a nitrogen atmosphere in the mill jar containing O2 < 0.1%, and an oxygen to zirconium content ratio of zirconia balls of 5:1 (if lower than 3:1, insufficient activation will occur). The rotation speed is 300 rpm; a rotation speed > 300 rpm will damage the MOF structure. The ball milling time is 1.5-2 hours. Activation mechanism: The impact of ball milling causes L-dopamine molecules to embed into the ZIF-8 channels (pore size...). ), with Cu 2+ The formation of a confined coordination structure improves catalytic efficiency by 400%.

[0060] Step 3, Supercritical Emulsification Method:

[0061] Step 3.1, phase sequence addition and premixing, such as Figure 2 As shown:

[0062] Step 3.1, Phase sequence addition and premixing:

[0063] Deionized water and borax-sodium carbonate buffer were added to the reactor, and the pH was adjusted to 8.0±0.2.

[0064] Add C6 fluorosurfactant (CF3(CF2)4COO-K) + The temperature was controlled at 25±2℃ and the mixture was stirred at 500 rpm for 5 minutes to form a homogeneous micelle system.

[0065] Add core-shell microspheres (hexaphenoxycyclotriphosphazene@zinc borate) and nanovalve microcapsules (CaO@thermally expandable polymer), and disperse at low speed of 300 rpm for 10 minutes;

[0066] Finally, add the silicon carbide nanowires and stir at 500 rpm for 2 minutes; if the silicon carbide nanowires are added first, their high specific surface area (≥60 m²) will be achieved. 2 / g) will competitively adsorb surfactants, increasing the bubble diameter to 70μm and extending the extinguishing time to 2.5s;

[0067] Stirring speeds exceeding 600 rpm will cause damage to the nanovalve microcapsules, with a breakage rate >15%.

[0068] Temperatures exceeding 28°C will lead to a decrease in micelle stability and a 25% increase in the separation rate;

[0069] Step 3.2, Supercritical CO2 emulsification:

[0070] Supercritical CO2 emulsification was performed using a supercritical reactor with a pressure ≥50 MPa and a CO2 pressure of 40 MPa to achieve nanoscale emulsification. The temperature was controlled at 65±1℃ to maintain the supercritical state of CO2. The shear rate was 15,000 rpm, the bubble size was controlled within the range of 48±5 μm, the emulsification time was 30 min, and the particle size distribution (PDI) was <0.1. The PDI value was monitored in real time relative to the CO2 pressure using an online laser particle size analyzer (Malvern Mastersizer 3000).

[0071] Step 4, Freeze-granulation method:

[0072] Step 4.1: Use liquid nitrogen cryogenic belt for cryogenic curing. The emulsion thickness is 2cm, the liquid nitrogen spray temperature is -45℃, and the cooling rate is ≥15℃ / min to prevent phase separation. Complete curing is achieved within 10min.

[0073] Step 4.2: Use a low-temperature crusher for crushing and screening. To avoid adhesion and agglomeration, the crushing temperature is controlled at -40℃. The crushing and screening adopts a double-layer vibrating screen with a screen aperture of 0.8mm / 1.2mm and a particle size of 0.8-1.2mm to maintain a balance between solubility and flowability.

[0074] Step 4.3: The vacuum drying temperature is 30℃ to prevent the heat-sensitive material from failing, the vacuum degree is -0.095MPa, and the Karl Fischer method is used to monitor the endpoint and control the moisture content to ≤0.5%.

[0075] The following describes in detail the operation steps and extinguishing mechanism of using the foam extinguishing agent described in this invention for fire extinguishing:

[0076] like Figure 3 As shown, the thermal triggering phase lasts for 0-0.1 seconds, with millisecond-level signal activation.

[0077] Nano spring valve response:

[0078] Thermally expanding polymer: Tg = 45℃, volume expands by 220% when heated;

[0079] The shell ruptures, releasing CaO nanoparticles with a particle size of 50 nm.

[0080] The following acid-base reactions occur locally:

[0081] CaO+H2O→Ca(OH)2ΔH=-63.7kJ / mol

[0082] pH changed from 7.0 to 9.2 (rate of increase: 20 pH / s)

[0083] Electron transfer catalysis:

[0084] Cu 2+ @ZIF-8 Hole Confined dopamine molecules catalyze electron transfer:

[0085]

[0086] The adhesion barrier phase lasts for 0.1-0.8 seconds.

[0087] The crosslinking kinetics of polydopamine are shown in Table 1 below:

[0088] Table 1

[0089] Time point crosslinking degree Film properties 0.1s 5％ Initial nucleation 0.3s 60％ 3D network covering surface 0.8s 95％ Dense film (thickness 200±50nm)

[0090] Adhesion enhancement mechanism:

[0091] Chemical bonding: The catechol group forms a chelate bond with the metal oxide (battery casing);

[0092] Physical anchoring: Polydopamine penetrates to a depth >1μm into the surface micropores;

[0093] Electrostatic adsorption: Positively charged polydopamine: Zeta = +35mV, adsorbs negatively charged electrodes;

[0094] Deep fire extinguishing stage: 0.8-1.5s, dual-phase flame retardancy and energy dissipation;

[0095] Vapor phase free radical quenching: 0.8-1.2 s;

[0096] The phosphazene shell softens (80℃), releasing PO· / P· free radicals;

[0097] Capturing H· / OH· free radicals in combustion chain reactions:

[0098] math

[0099] PO·+H·->POH

[0100] P· + OH· -> POH

[0101] The traditional DMMP quenching rate is 58%, while the PO quenching rate of this technology is 92%, as verified by ReaxFF simulation.

[0102] Solid-phase ceramic isolation: 1.0-1.5s;

[0103] The melting temperature of the zinc borate core is 600℃, which forms the Zn-BO-Si ceramic layer.

[0104] Ionic conductivity <10 -6 S / cm can prevent internal short circuits in the battery;

[0105] The ceramic layer reduces the short-circuit current inside the battery from 18A to 0.05A;

[0106] Its thermal conductivity is 0.8 W / (m·K), which is only 1 / 100 of that of the electrode material;

[0107] Micro-explosion heat absorption occurs throughout the entire process;

[0108] Silicon carbide nanowires (50 nm) undergo micro-explosions at temperatures above 800°C;

[0109] math

[0110] SiC+2O2→SiO2+CO2ΔH=-989kJ / mol

[0111] Heat absorbed: 1.5 kJ / g (actual cooling rate: 1200℃ / s);

[0112] Special mechanisms to prevent battery fires:

[0113] Blocking the thermal runaway chain reaction:

[0114] Gas-phase blocking: The phosphazene shell softens at 80℃, releasing PO· free radicals, which quench the H· / OH· free radicals in the combustion chain reaction (quenching rate 92%).

[0115] Solid-phase isolation: The zinc borate core is melted at 600℃ to form a Zn-BO-Si ceramic layer, blocking internal short circuits in the battery (ionic conductivity <10). -6 S / cm).

[0116] Thermal propagation suppression: The thermal conductivity of the ceramic layer is only 0.8 W / (m·K), delaying heat transfer between adjacent cells by >60 min;

[0117] It should be noted that the extinguishing agent blocks the chain reaction through a two-stage response, and the PO· free radicals released by phosphazene capture gaseous H· / OH· free radicals (quenching rate 92%); the ceramic layer formed by the melting of zinc borate isolates the electrode, reducing the internal short-circuit current from 18A to 0.05A, thus completely terminating the electrochemical reaction.

[0118] Triple flameout protection is shown in Table 2 below.

[0119] Table 2

[0120]

[0121] The mechanism of this invention is compared with that of traditional fire extinguishing agents, as shown in Table 3 below:

[0122] Table 3

[0123]

[0124]

[0125] The performance of the foam fire extinguishing agent described in this invention is supported by experimental verification data:

[0126] High-speed microscopic observation (100,000 fps);

[0127] 0.12s: Diffusion trajectory of CaO nanoparticles, calculated using a particle tracking algorithm;

[0128] 0.25s: The spreading speed of the polydopamine network on the 304 stainless steel surface is 1.2m / s;

[0129] 0.78s: Phosphazene shell phase transition process (Simultaneous DSC verification);

[0130] Molecular dynamics simulation of ReaxFF force field:

[0131] Dopamine in Cu 2+The adsorption energy at the site is -185 kJ / mol, which is significantly stronger than that of ordinary copper foil (-92 kJ / mol); the PO radical quenching efficiency is 90% of the OH radicals removed within 10 ps.

[0132] Battery-grade fire suppression verification data are shown in Table 4 below:

[0133] Table 4

[0134] parameter Thermal runaway battery module After the technical intervention of this invention highest temperature ＞860℃ 62℃ (at 1.5s) Voltage sag rate -48V / s -0.5V / s CO emissions 1200ppm <5ppm Internal pressure 1.8MPa 0.1MPa

[0135] The fire extinguishing effectiveness, as tested by a third party, is shown in Table 5 below:

[0136] Table 5

[0137]

[0138] The changes in time with physical, chemical, and temperature effects are shown in Table 6 below.

[0139] Table 6

[0140]

[0141] Actual verification examples of the foam fire extinguishing agent described in this invention

[0142] Basic formulation components: Based on a total mass percentage of 100%, the remainder is deionized water and buffer, L-dopamine 1.8% + norepinephrine 2.7% + core-shell microspheres 3.2% + nanovalve microcapsules 1.8% + Cu 2+ @ZIF-8 0.9% + Silicon Carbide 0.3% + C6 Fluorine Surfactant 0.5%;

[0143] Actual fire extinguishing performance is shown in Table 7 below:

[0144] Table 7

[0145] Test Project result extinguishing time of ternary lithium battery 1.48±0.05s Sodium battery reignition rate 0％(72h) Copper ion leaching amount 0.07 mg / L

[0146] For ternary lithium battery modules with a capacity of 60Ah or higher (SOC ≥ 80%), the spraying distance reaches 0.3-0.5m;

[0147] Validation of the core-shell microsphere structure:

[0148] TEM measurement of shell thickness: 82 nm;

[0149] Laser particle size analyzer detected core D50: 3.25μm.

[0150] Fluorine-free environmentally friendly variants:

[0151] Adjustments: C6 fluorine surfactant → replace with alkyl glycoside 1.0% + sodium lauroyl sarcosinate 0.6%, use triethanolamine to replace borax to adjust pH, and avoid the reaction of sodium carbonate with fluorine-free surfactant;

[0152] Actual results: Surface tension: 19.3 mN / m; Foaming ratio: 5.8;

[0153] PFAS residue: Not detected.

[0154] High-load performance enhancement version:

[0155] Adjustments: Core-shell microspheres increased to 4.0% + nanovalve microcapsules 2.2%;

[0156] Actual results: Solid-state battery fire extinguishing time: 1.22±0.03s; Thermal propagation blocking rate: 100%;

[0157] Technical effects:

[0158] The fire extinguishing performance of routine tests is shown in Table 8 below.

[0159] Table 8

[0160] Test Project National Standards This invention was measured. Compared with existing technologies Lithium battery fire extinguishing time ≤30s (GB / T31467.3) 1.45±0.08s >30s (CN114452677A) 25% precipitation time ≥15min 38.7min 12min (commercially available AFFF) Vertical surface retention rate ≥70％ 98.2％ 28.5% (perfluorohexanone) Heat spread blocking rate No regulations 100％ ≤65% (US20220305321) 72h reignition rate 0％ 0％ 42% (ABC dry powder)

[0161] It should be noted that the lithium battery fire extinguishing time test is for ternary lithium battery modules with a capacity of 60Ah or higher (SOC≥80%), with a spray distance of 0.3-0.5m.

[0162] The structural correlation test results are shown in Table 9 below:

[0163] Table 9

[0164] Test Project This invention was measured. Structural dependency Flame retardant response delay time 0.31s When the shell thickness is >90nm, the time delay is >0.5s. Ceramic layer integrity No cracks When the kernel particle size is >4μm, the cracking rate is >60%.

[0165] Environmental and safety performance:

[0166] PFAS content: 0.75%, which meets the limit of <1% in China's "List of Key Controlled New Pollutants";

[0167] Heavy metal leaching: Cu 2+ 0.07 mg / L, which is less than the limit of 1 mg / L in GB 8978-1996;

[0168] Acute oral toxicity: LD 50 >5000mg / kg, complies with GB 15193.3-2014, and belongs to the non-toxic category;

[0169] Biodegradability: 92.3% degradation rate after 28 days (OECD 301B requirement >80%);

[0170] Industry adaptability:

[0171] Storage stability: Accelerated aging tests showed no stratification after 2 years at temperatures ranging from -20℃ to 50℃;

[0172] Ease of use: Frozen granules dissolve in 1 second and are compatible with existing compressed air foam systems.

[0173] The following technical details were further verified through experiments:

[0174] Quantitative relationship between core-shell thickness and performance:

[0175] Experiments revealed that when the shell thickness was 80±10 nm, the phosphazene release rate reached a peak of 0.22 mg / (cm³). 2 •s); The softening time of the outer shell at 80°C is exactly 0.3s (matching the adhesion layer formation time);

[0176] If the thickness deviates from this range:

[0177] <70nm: Premature release of flame retardant (storage period <1 month);

[0178] >90nm: Flame retardant delay results in extinguishing time >2s;

[0179] Risk avoidance design

[0180] The shell thickness is preferably 80±10nm, but an equivalent effect can also be achieved by adjusting the concentration of phosphazene in the range of 70-90nm;

[0181] Supported by experimental evidence:

[0182] Three sets of comparative experimental data are provided for shell thicknesses of 70nm, 80nm, and 90nm. The experimental data prove that the performance is optimal at 80nm.

[0183] This invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its concept and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims.

Claims

1. A new energy battery foam extinguishing agent based on biomimetic dopamine adhesion and core-shell flame retardant synergy, comprising: Adhesion prerequisite, flame retardant synergist, thermal management material, foaming matrix, pH trigger system, catalytic carrier, solvent and buffer, wherein: the adhesion prerequisite is L-dopamine + norepinephrine, the molar ratio is 1:2; the flame retardant synergist is hexaphenoxy cyclotriphosphazene@zinc borate core-shell microspheres, the shell thickness is 80±10nm, the inner core particle size is 3.2±0.5μm; the silicon carbide nanowire diameter is 50nm, the length is 10μm, the microburst endothermic ΔH is-989kJ / mol; the foaming matrix is C6 fluorine surfactant, the surface tension of the fire extinguishing agent aqueous solution is reduced to 17.2mN / m, the pH trigger system is nanospring valve microcapsule CaO@thermal expansion polymer: the trigger time is 0.1 second, the pH transient is 7.0→9.2; the catalytic carrier is Cu 2+ @ZIF-8 metal organic framework; the solvent and buffer are deionized water+borax-sodium carbonate buffer, the pH value is maintained at 8.0±0.

2.

2. The new energy battery ultra-fast foam extinguishing agent based on bionic dopamine adhesion and core-shell flame retardation synergy according to claim 1, wherein the mass percentage of L-dopamine + norepinephrine is 3.0-5.0%; the mass percentage of hexaphenoxy cyclotriphosphazene@zinc borate core-shell microspheres is 2.5-4.0%; the mass percentage of silicon carbide nanowires is 0.2-0.5%; the mass percentage of C6 fluorine surfactant is 0.3-0.8%; the mass percentage of nano spring valve microcapsules is 1.0-2.5%; the mass percentage of Cu 2+ @ZIF-8 metal organic framework is 0.5-1.2%; and the mass percentage of deionized water + borax-sodium carbonate buffer is the balance.

3. The new energy battery ultra-fast foam extinguishing agent based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardant according to claim 1, according to the mass percentage content: L-dopamine + norepinephrine before adhesion is 4.0%; the flame retardant synergist is hexaphenoxy cyclotriphosphazene@zinc borate core-shell microspheres, which is 3.2%; silicon carbide nanowires are 0.35%; C6 fluorine surfactant is 0.5%; nano spring valve microcapsules are 1.8%; Cu 2+ @ZIF-8 metal organic framework is 0.5-1.2%; deionized water + borax-sodium carbonate buffer is the balance.

4. The preparation method of the foam extinguishing agent based on biomimetic dopamine adhesion and core-shell flame retardant synergy for new energy batteries according to claim 1, comprising: Step 1, core-shell microsphere preparation; Step 2, catalytic carrier activation method; Step 3, supercritical emulsification method; Step 4, freeze granulation method.

5. The preparation method of the foam extinguishing agent based on biomimetic dopamine adhesion and core-shell flame retardant synergy for new energy batteries according to claim 4, wherein the core-shell microsphere preparation of step 1 comprises the following specific steps: Step 1.1, the raw material for zinc borate microsphere pretreatment is battery-grade zinc borate, a fluidized bed coater is used, the inlet air temperature of the fluidized bed preheater is controlled at 45±2℃, and a temperature >50℃ leads to premature softening of the core-shell shell of the microspheres; the atomization pressure of the microsphere fluidization is 0.8 Bar, which ensures that the droplet particle size is controlled within 10-20μm; the spraying rate of phosphazene is 8mL / min, the spraying amount per kilogram of microspheres is 120mL, the dry film formation time is 30min, and the residual solvent is controlled <0.1%; Step 1.2, nano spring valve loading method: An electrostatic adsorption method is used to disperse the nano spring valve microcapsules in 5wt% ethanol, a -15kV static voltage is applied, the microcapsules are directionally adsorbed to the surface of the core-shell microspheres, 0.1% polyvinylpyrrolidone anti-agglomerating agent is added to the ethanol dispersion, the humidity in the electrostatic adsorption chamber is ≤30%RH, the adsorption rate is controlled at 92±3%, and the calcium element distribution is determined by SEM-EDS.

6. The preparation method of the foam extinguishing agent based on biomimetic dopamine adhesion and core-shell flame retardant synergy for new energy batteries according to claim 4, wherein the catalytic carrier activation method of step 2 comprises the following specific steps: Step 2.1, MOF confined catalytic activation: using a planetary ball mill, ball mill jar atmosphere is nitrogen, O2<0.1%, the oxygen to zirconium content ratio of zirconium balls is 5:1, if lower than 3:1, the activation will be insufficient, the rotation speed is 300 rpm, rotation speed > 300 rpm will lead to the destruction of the MOF structure, the ball milling time is 1.5-2h, the activation mechanism: ball milling impact makes L-dopamine molecules embedded in the ZIF-8 channel, the pore size is Cu 2+ forms a confined coordination structure.

7. The preparation method of the foam extinguishing agent based on biomimetic dopamine adhesion and core-shell flame retardant synergy for new energy batteries according to claim 4, wherein the supercritical emulsification method of step 3 comprises the following specific steps: Step 3.1, phase sequence addition and premixing: Deionized water and borax-sodium carbonate buffer are added to the reaction kettle, and the pH is adjusted to 8.0±0.2; C6 fluorine surfactant is added, the temperature is controlled at 25±2℃, and stirring is carried out at 500rpm for 5 minutes to form a uniform micellar system; Core-shell microspheres (hexaphenoxy cyclotriphosphazene@zinc borate) and nano valve microcapsules are added, and 300rpm low-speed shear dispersion is carried out for 10 minutes; Silicon carbide nanowires are then added, and stirring is carried out at 500rpm for 2 minutes; Step 3.2, supercritical CO2 emulsification: Supercritical CO2 emulsification is carried out using a supercritical reaction kettle, the pressure of the supercritical reaction kettle is ≥50MPa, the CO2 pressure is 40MPa, nano-scale emulsification is achieved, the temperature is controlled at 65±1℃ to maintain the supercritical state of CO2, the shear rate is 15,000rpm, the bubble diameter is controlled within 48±5μm, the emulsification time is 30min, and the particle size PDI is <0.1; when the CO2 pressure is 40MPa, an online laser particle size analyzer is used to monitor the particle size PDI value in real time.

8. The preparation method of the new energy battery foam extinguishing agent based on the synergistic effect of biomimetic dopamine adhesion and core-shell flame retardance according to claim 4, wherein the freeze granulation method in step 4 comprises the following specific steps: Step 4.1, deep freezing solidification, using a liquid nitrogen deep freezing belt, the emulsion is laid flat with a thickness of 2 cm, the liquid nitrogen spray temperature is -45℃, the cooling rate is ≥15℃ / min, phase separation is prevented, and complete solidification is achieved within 10 min; Step 4.2, crushing and screening, using a low-temperature crusher, the crushing temperature is controlled at -40℃ to avoid adhesion and agglomeration, a double-layer vibrating screen is used for crushing and screening, the screen mesh aperture is 0.8mm / 1.2mm, the particle size is 0.8-1.2mm, and the balance between instant solubility and fluidity is maintained; Step 4.3, vacuum drying temperature is 30℃, heat-sensitive materials are prevented from failing, the vacuum degree is -0.095MPa, and the Karl Fischer method is used to monitor the end point to control the moisture content to be ≤0.5%.

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