Double-response type flame-retardant fire extinguishing agent for solid-state battery and preparation method thereof

Abstract

The invention discloses a double-response type flame-retardant fire extinguishing agent for a solid-state battery, which is prepared from the following components in percentage by mass: 30 to 40 percent of TMEP, 12 to 18 percent of HBCD, 15 to 25 percent of DME, 15 to 22 percent of hydrated zinc borate, 8 to 15 percent of silane coupling agent and 0.01 to 0.05 percent of polyether defoaming agent. The invention further provides a preparation method of the flame-retardant fire extinguishing agent. Through formula design, the synergistic effect of early permeation inhibition and high-temperature cooling barrier is achieved, the interface reaction delay time is prolonged by 200%, the melt cooling rate is increased by 3 times, and through the synergistic effect of a low-viscosity formula and a silane coupling agent, the permeation depth of the fire extinguishing agent on a solid electrolyte interface is larger than or equal to 50 micrometers, and the adhesion rate is larger than or equal to 70%; dehydration heat absorption of hydrated zinc borate is combined with a gas barrier of HBCD, melt with the temperature of 800 DEG C or above can be reduced to 300 DEG C or below within 3 seconds, and reburning is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy battery safety protection, more specifically, to a dual-response type flame-retardant extinguishing agent suitable for sulfide, oxide and other solid-state electrolyte batteries and a preparation method thereof, which is aimed at the characteristics of "intense interface reaction and high-temperature molten splashing" of solid-state batteries in thermal runaway, and realizes early inhibition and fire extinguishing temperature control through staged injection. BACKGROUND

[0002] Solid-state batteries have become the core direction of the next generation of battery technology due to their high energy density and non-flammable electrolyte characteristics, but still have the risk of thermal runaway. Sulfide solid-state electrolytes will react violently with positive electrodes at 200-300℃, releasing a large amount of heat. Although oxide solid-state electrolytes have good thermal stability, splashing of molten electrode materials at high temperatures (>600℃) can easily cause secondary fires.

[0003] Existing fire extinguishing agents cannot adapt to the special failure mode of solid-state batteries: first, it is difficult to penetrate the interface gap between solid-state electrolytes and electrodes, and cannot inhibit the interface reaction; second, the cooling capacity for high-temperature molten materials (>800℃) is insufficient, which can easily lead to reignition. Solid-state battery thermal runaway presents three-stage characteristics of "interface reaction-temperature rise-molten splashing", and requires the fire extinguishing agent to quickly penetrate the interface in the early stage, efficiently cool in the middle stage, and cover and block the molten material in the later stage. The existing technology has not yet formed a targeted solution, so it is urgent to develop a special flame-retardant extinguishing agent for solid-state batteries. SUMMARY

[0004] To overcome the deficiencies of the prior art, one of the purposes of the present application is to provide a dual-response type flame-retardant extinguishing agent for solid-state batteries, which can inhibit the interface reaction by low-viscosity penetration injection in the early stage of thermal runaway (200-300℃), and can block the molten splashing and reignition by high-pressure cooling injection in the high-temperature molten stage (>600℃), ensuring that the penetration depth of the fire extinguishing agent is ≥50μm (covering the electrode-electrolyte interface) in the early injection, and the temperature of the molten material is reduced from 800℃ to below 300℃ within 3 seconds after injection in the high-temperature stage, solving the diffusion problem of the fire extinguishing agent in the porous electrode structure of the solid-state battery, and the low decomposition efficiency of the flame-retardant component at high temperatures.

[0005] To solve the above technical problems, the present application provides the following technical solutions: The double-response type fire extinguishing agent for solid-state batteries is composed of the following components in terms of mass percentage: tri (2-methoxyethyl) phosphate (TMEP) 30-40%, hexabromocyclododecane (HBCD) 12-18%, ethylene glycol dimethyl ether (DME) 15-25%, hydrated zinc borate (2ZnO 3B2O3 3.5H2O) 15-22%, silane coupling agent 8-15%, and polyether defoaming agent 0.01-0.05%; wherein the mass ratio of tri (2-methoxyethyl) phosphate to ethylene glycol dimethyl ether is (1.5-2.0):1, and the total mass percentage of hexabromocyclododecane and hydrated zinc borate is ≤35%.

[0006] TMEP, as the core flame-retardant component in the early penetration stage, has low viscosity (25℃ viscosity 4.2mPa・s) and high permeability (surface tension 28mN / m), can quickly penetrate into the interface gap of solid-state electrolyte and electrode (penetration depth ≥50μm), and generate PO・free radicals at 220℃ to inhibit the active intermediates (such as S2 - , O 2- ) generated by interface reaction; HBCD, as a physical flame retardant in the high-temperature stage, sublimates to form a brominated gas barrier above 300℃, captures high-temperature free radicals, and at the same time, its molten state (190℃) can wrap the electrode melt to prevent splashing; DME is used to adjust the penetration fluidity, has excellent compatibility with TMEP (no stratification after mixing and standing for 72h), reduces the system viscosity to 3.8mPa・s, and ensures that it can still penetrate quickly at low temperature (-20℃); Hydrated zinc borate is used as a high-temperature cooling flame retardant, releases crystal water upon heating (dehydration starts at 250℃), absorbs a large amount of latent heat (dehydration enthalpy 1200J / g), and at the same time generates a B2O3 glassy coating to cover the surface of the melt and isolate oxygen; The silane coupling agent is used to enhance the interfacial adhesion, reacts with the surface hydroxyl groups of the solid-state electrolyte (such as Li7La3Zr3O 12 ) on one end, and combines with the flame-retardant components on the other end, so that the adhesion rate of the fire extinguishing agent on the interface is increased by 40% and the action time is prolonged.

[0007] The application is aimed at the special failure mode of solid-state battery "interface reaction-melt splash", through formula design to realize the synergistic effect of early penetration inhibition and high-temperature cooling barrier, the interface reaction delay time is increased by 200%, the melt cooling rate is increased by 3 times, the synergistic effect of low viscosity formula and silane coupling agent makes the penetration depth of fire extinguishing agent on the interface of solid electrolyte ≥50μm, the adhesion rate ≥70%, solves the technical problem that traditional fire extinguishing agent is difficult to enter the interface gap, the dehydration endothermic of hydrated zinc borate and the gas barrier of HBCD can reduce the melt above 800℃ to below 300℃ in 3 seconds, and there is no afterburning, which is significantly better than the existing fire extinguishing agent (cooling time > 10 seconds).

[0008] Preferably, the silane coupling agent is KH-550.

[0009] The second object of the application is to provide a preparation method of the above-mentioned double-response type flame-retardant fire extinguishing agent for solid-state battery, comprising the following steps: (1) Raw material pretreatment: tris (2-methoxyethyl) phosphate is treated by 3A molecular sieve dehydration to a water content of ≤20ppm, hexabromocyclododecane is crushed to a particle size of ≤5μm, and hydrated zinc borate is treated by vacuum drying to remove surface adsorbed water; (2) Liquid component premixing: add ethylene glycol dimethyl ether and tris (2-methoxyethyl) phosphate pretreated in step (1) into an explosion-proof stirred tank, replace 3 times with high-purity nitrogen gas with a purity of 99.999%, stir, form a uniform solution, then add a silane coupling agent, heat and stir for a period of time, and then cool to room temperature; (3) Solid phase component dispersion: add hydrated zinc borate and hexabromocyclododecane pretreated in step (1) into the liquid phase system prepared in step (2), replace the stirring paddle of the explosion-proof stirred tank with a dispersion disc, continue to stir, and prepare a dispersion system; (4) Response characteristic regulation: add a polyether defoaming agent to the dispersion system of step (3), stir, then vacuum degas to ensure that the system is bubble-free, and prepare a flame-retardant fire extinguishing agent product, which is packaged in an aluminum pressure tank in a nitrogen environment.

[0010] Preferably, in step (1), tris (2-methoxyethyl) phosphate is treated by 3A molecular sieve dehydration for 30-40h.

[0011] Preferably, in step (1), the hydrated zinc borate is vacuum dried at 90-110℃ for 1-2h to remove surface adsorbed water.

[0012] Preferably, in step (2), the initial stirring temperature is room temperature, the stirring rate is 300-400r / min, and the stirring time is 8-15min.

[0013] Preferably, in step (2), after the silane coupling agent is added, the temperature is raised to 40°C and stirring is continued for 15-25 min.

[0014] Preferably, in step (3), the stirring rate is 550-650 r / min and the stirring time is 30-45 min.

[0015] Preferably, in step (4), the stirring rate is 450-550 r / min and the stirring time is 5 min.

[0016] Preferably, in step (4), the vacuum degree during vacuum degassing is -0.095 MPa and the vacuum degassing time is 30 min.

[0017] Dual-response jetting mechanism: Interface infiltration stage (200-300°C) When the battery management system detects that the temperature reaches 200°C or the solid-state electrolyte impedance abnormally rises (> 500 mΩ), the low-pressure infiltration jetting system is triggered: a micro-diaphragm pump sprays the extinguishing agent from an array of micro-nozzles (pore diameter 0.2 mm, spacing 5 mm) at a pressure of 0.3 MPa, and the TMEP penetrates to the electrode-electrolyte interface within 10 seconds due to its low surface tension characteristics. In the 200-300°C range, the PO・free radicals generated by the decomposition of TMEP react with S2 - , O 2- combined, inhibiting the reaction chain transmission, reducing the interface reaction rate by 70%, and delaying the time for the temperature to rise to the melting point (from 50 seconds to 120 seconds).

[0018] High-temperature cooling stage (> 600°C) When the infrared sensor detects a local temperature > 600°C or a molten material splashing signal, the high-pressure cooling jetting system is started: a plunger pump sprays the extinguishing agent from a fan-shaped nozzle (spray angle 90°) at a pressure of 3 MPa, with a flow rate of 20 m / s covering the surface of the battery. Hydrated zinc borate rapidly dehydrates at high temperatures, absorbing heat to reduce the temperature of the molten material from 800°C to below 300°C; HBCD sublimates to form a bromide gas barrier, inhibiting high-temperature rekindling; at the same time, the silane coupling agent promotes the bonding of the B2O3 coating with the surface of the molten material, preventing secondary splashing (experimental verification: the range of molten material splashing is reduced from 30 cm to 5 cm).

[0019] Compared with the prior art, the beneficial effects of the present application are: 1. The present application is aimed at the special failure mode of solid-state battery "interface reaction-melt splash", through formula design to realize the synergistic effect of early penetration inhibition and high temperature cooling barrier, the interface reaction delay time is improved by 200%, the melt cooling rate is improved by 3 times, the synergistic effect of low viscosity formula and silane coupling agent makes the penetration depth of fire extinguishing agent in the interface of solid electrolyte ≥50μm, the adhesion rate ≥70%, solves the technical problem that the traditional fire extinguishing agent is difficult to enter the interface gap, the dehydration endothermic of hydrated zinc borate and the gas barrier of HBCD can reduce the melt above 800℃ to below 300℃ in 3 seconds, and there is no afterglow, which is significantly better than the existing fire extinguishing agent (cooling time > 10 seconds).

[0020] 2. The formula of the present application has good compatibility with sulfide and oxide solid electrolyte (impedance change rate ≤5%), does not affect the normal work of the battery, is suitable for various solid-state battery systems, the raw materials are all industrialized products, the preparation process can be realized by conventional dispersion equipment, the batch performance deviation is ≤4%, has the conditions for large-scale production, and fills the technical blank of special fire extinguishing agent for solid-state battery. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The preparation flow chart of the double-response type flame-retardant fire extinguishing agent for solid-state battery of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0023] The test materials and reagents used in the following examples, etc. can be obtained from commercial channels if not specially specified, and the specific techniques or conditions not noted in the examples can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0024] Example 1: Preparation of double-response type flame-retardant fire extinguishing agent for solid-state battery (1) Raw material pretreatment: TMEP is dehydrated by 3A molecular sieve for 30h to its water content ≤20ppm, HBCD is crushed to particle size ≤5μm using an air flow crusher to ensure rapid sublimation at high temperature, hydrated zinc borate is vacuum dried at 90℃ for 2h to remove surface adsorbed water (to avoid forming hydrogen bonds with DME affecting fluidity); (2) Liquid component premixing: add TMEP (350 g) and DME (200 g) into a 5L explosion-proof stirred tank, replace three times with high-purity nitrogen (99.999%), stir at a rate of 300 r / min for 15 min to form a uniform solution, then add silane coupling agent KH-550 (120 g) to it, and continue to stir at 40°C for 15 min (to promote the hydrolysis and activation of the silane coupling agent), and cool to room temperature; (3) Solid phase component dispersion: add HBCD (150 g) and hydrated zinc borate (180 g) to the above liquid phase system, replace the stirring paddle with a dispersion disc (linear speed 15 m / s), and stir at a rate of 550 r / min for 45 min (to ensure that the micro-nozzles are not blocked during spraying); (4) Response characteristic regulation: add polyether defoaming agent (0.2 g) to the dispersion system of step (3), stir at a rate of 450 r / min for 5 min, vacuum degas (vacuum degree -0.095 MPa) for 30 min, and ensure that the system is bubble-free (to avoid air blockage during penetration), and finally package the product in an aluminum pressure tank (working pressure 0.8 MPa) in a nitrogen environment to ensure the stability of the pressure during spraying.

[0025] Example 2: Preparation of a dual-response type flame retardant extinguishing agent for solid-state batteries (1) Raw material pretreatment: TMEP is dehydrated for 36 h with 3A molecular sieves (water content 18 ppm), and a gas flow crusher is used to process HBCD to a particle size of D50=4.8 μm to ensure rapid sublimation at high temperatures, and hydrated zinc borate is vacuum dried at 100°C for 2 h to remove surface adsorbed water to a surface water content of ≤0.5% (to avoid the formation of hydrogen bonds with DME affecting flowability); (2) Liquid component premixing: add TMEP (350 g) and DME (200 g) into a 5L explosion-proof stirred tank, replace three times with high-purity nitrogen (99.999%), stir at a rate of 350 r / min for 10 min to form a uniform solution, then add silane coupling agent KH-550 (120 g) to it, and continue to stir at 40°C for 20 min (to promote the hydrolysis and activation of the silane coupling agent), and cool to room temperature; the mixed liquid is clear and transparent, and the silane coupling agent hydrolysis rate is ≥90% detected by infrared spectroscopy; (3) Solid phase component dispersion: add HBCD (150 g) and hydrated zinc borate (180 g) to the above liquid phase system, replace the stirring paddle with a dispersion disc (linear speed 15 m / s), and stir at a rate of 600 r / min for 40 min, detect the solid phase particle D50=2.5 μm by laser particle size analyzer (to ensure that the micro-nozzles are not blocked during spraying), and the system viscosity is 4.0 mPa・s (25°C); (4) Response characteristic regulation: Add polyether defoaming agent (0.2 g) to the dispersion system of step (3), stir at a speed of 500 r / min for 5 min, vacuum degassing (vacuum degree is -0.095 MPa) for 30 min, ensure that the system is free of bubbles (avoid air blockage when permeating), and finally package the product in an aluminum pressure-resistant tank (working pressure 0.8 MPa) under a nitrogen environment to ensure the stability of the pressure during spraying.

[0026] Example 3: Preparation of a double-response type fire extinguishing agent for solid-state batteries (1) Raw material pretreatment: TMEP is dehydrated by 3A molecular sieve for 40 h to a water content of ≤20 ppm, a gas flow crusher is used to process HBCD to a particle size of ≤5 μm to ensure rapid sublimation at high temperature, and zinc borate is vacuum dried at 110°C for 1 h to remove surface adsorbed water (to avoid forming hydrogen bonds with DME and affecting fluidity); (2) Liquid phase component premixing: Add TMEP (350 g) and DME (200 g) into a 5 L explosion-proof stirred tank, replace three times with high-purity nitrogen (99.999%), stir at a speed of 400 r / min for 8 min to form a uniform solution, then add silane coupling agent KH-550 (120 g) to it, heat to 40°C and continue to stir for 25 min (to promote the hydrolysis and activation of the silane coupling agent), and cool to room temperature; (3) Solid phase component dispersion: Add HBCD (150 g) and zinc borate (180 g) to the above liquid phase system, replace the stirring paddle with a dispersing disc (linear speed 15 m / s), and stir at a speed of 650 r / min for 30 min (to ensure that the micro-nozzles are not blocked during spraying), and the system viscosity is 4.0 mPa・s (25°C); (4) Response characteristic regulation: Add polyether defoaming agent (0.2 g) to the dispersion system of step (3), stir at a speed of 550 r / min for 5 min, vacuum degassing (vacuum degree is -0.095 MPa) for 30 min, ensure that the system is free of bubbles (avoid air blockage when permeating), and finally package the product in an aluminum pressure-resistant tank (working pressure 0.8 MPa) under a nitrogen environment to ensure the stability of the pressure during spraying.

[0027] Comparative example Comparative example 1: The difference between this comparative example and example 2 is that TMEP is not added to the raw materials, and the interface reaction rate is only reduced by 30% after early spraying, and the temperature rises to 600°C for 70 seconds (example 2 is 150 seconds).

[0028] Comparative example 2: The difference between this comparative example and example 2 is that anhydrous zinc borate is not added to the raw materials, and the temperature of the molten material decreases to 450°C after high-temperature spraying (example 2 is 280°C), and rises to 500°C after 30 seconds (recurrence occurs).

[0029] Comparative Example 3: The difference between this comparative example and Example 2 is that no silane coupling agent is added to the raw material, the adhesion rate of the extinguishing agent at the interface is only 30% (70% in Example 2), and the action time is shortened to 40 seconds.

[0030] Performance test (solid-state battery scenario verification) 1. Early penetration test: sulfide solid-state battery (LiNi0.8Co0.1Mn0.1O2 / Li7P3S 11 ) triggered jet at 200℃, penetration depth 58μm within 10 seconds, interface reaction rate reduced by 72%, temperature increased to 600℃ for 150 seconds (non-jet group 50 seconds).

[0031] 2. High temperature cooling test: oxide solid-state battery (LiCoO2 / LLZO) jet at melting stage, under a flow rate of 20m / s, the molten temperature decreased from 820℃ to 280℃ within 3 seconds, the splash range reduced to 4.5cm, and there was no re-ignition.

[0032] 3. Material compatibility: contact with LLZO solid-state electrolyte for 30 days, electrolyte impedance change rate ≤5% (tested by electrochemical workstation), no corrosion phenomenon.

[0033] The present application is aimed at the special failure mode of "interface reaction-molten splash" of solid-state batteries. Through formula design, the synergistic effect of early penetration inhibition and high temperature cooling barrier is achieved, the interface reaction delay time is increased by 200%, the molten material cooling rate is increased by 3 times, the synergistic effect of low viscosity formula and silane coupling agent makes the penetration depth of extinguishing agent at the interface of solid-state electrolyte ≥50μm, and the adhesion rate ≥70%, solving the technical problem that traditional extinguishing agents are difficult to enter the interface gap. The dehydration endothermic of hydrated zinc borate and the gas barrier of HBCD can reduce the molten material above 800℃ to below 300℃ within 3 seconds without re-ignition, which is significantly better than the existing extinguishing agent (cooling time >10 seconds).

[0034] The present application discloses a preferred embodiment, but is not limited thereto. Those skilled in the art can easily understand the spirit of the present application and make different inferences and changes based on the above examples, as long as they do not deviate from the spirit of the present application, and are within the scope of protection of the present application.

Claims

1. A dual-response flame-retardant extinguishing agent for solid-state batteries, characterized in that, It is composed of the following components, by mass percentage: tris(2-methoxyethyl) phosphate 30-40%, hexabromocyclododecane 12-18%, ethylene glycol dimethyl ether 15-25%, zinc borate hydrate 15-22%, silane coupling agent 8-15%, and polyether defoamer 0.01-0.05%; The mass ratio of tris(2-methoxyethyl) phosphate to ethylene glycol dimethyl ether is (1.5-2.0):1, and the total mass percentage of hexabromocyclododecane and zinc borate hydrate is ≤35%.

2. The dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 1, characterized in that: The silane coupling agent is KH-550.

3. A method for preparing a dual-response flame-retardant fire extinguishing agent for solid-state batteries as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Raw material pretreatment: Tris(2-methoxyethyl) phosphate was dehydrated by 3A molecular sieve until its water content was ≤20ppm, hexabromocyclododecane was pulverized to a particle size ≤5μm, and zinc borate hydrate was vacuum dried to remove surface adsorbed water; (2) Premixing of liquid components: Ethylene glycol dimethyl ether and the tris(2-methoxyethyl) phosphate pretreated in step (1) are added to an explosion-proof stirred tank, and high-purity nitrogen gas with a purity of 99.999% is introduced to replace the solution three times. The mixture is stirred to form a uniform solution. Then, silane coupling agent is added to the solution, and the mixture is heated and stirred for a period of time before being cooled to room temperature. (3) Solid phase component dispersion: Add zinc borate hydrate and hexabromocyclododecane pretreated in step (1) to the liquid phase system obtained in step (2), replace the stirring paddle of the explosion-proof stirring tank with a dispersion plate, and continue stirring to obtain a dispersion system. (4) Response characteristics regulation: Add polyether defoamer to the dispersion system in step (3), and after stirring, use vacuum degassing to ensure that there are no bubbles in the system, and obtain flame retardant fire extinguishing agent product. The product is packaged in an aluminum pressure tank under nitrogen environment.

4. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (1), tris(2-methoxyethyl) phosphate is dehydrated by 3A molecular sieve for 30-40 hours.

5. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (1), zinc borate hydrate is vacuum dried at 90-110℃ for 1-2 hours to remove surface adsorbed water.

6. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (2), the initial stirring temperature is room temperature, the stirring rate is 300-400 r / min, and the stirring time is 8-15 min.

7. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (2), after adding the silane coupling agent, the temperature is raised to 40°C and stirring is continued for 15-25 minutes.

8. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (3), the stirring rate is 550-650 r / min and the stirring time is 30-45 min.

9. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (4), the stirring rate is 450-550 r / min and the stirring time is 5 min.

10. The preparation method of the dual-response flame-retardant extinguishing agent for solid-state batteries according to claim 3, characterized in that: In step (4), the vacuum degree during vacuum degassing is -0.095MPa, and the vacuum degassing time is 30min.

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