Lithium battery fire extinguishing agent and preparation method thereof

Abstract

The invention relates to the technical field of fire extinguishing agents, and particularly discloses a lithium battery fire extinguishing agent and a preparation method thereof. The degradable surfactant is selected from at least one of alkyl glycoside and fatty acid methyl ester sulfonate; the particle size of the nanoscale silicon dioxide particles is 10 to 100 nm; the composite flame retardant is formed by compounding an organic phosphorus compound and graphene oxide according to a mass ratio of 1: (0.5-2); the antifreeze agent is selected from at least one of ethylene glycol and propylene glycol; the thickening agent is selected from at least one of xanthan gum and sodium carboxymethyl cellulose; the preservative is selected from at least one of sodium benzoate and potassium sorbate; through the synergistic effect of the composite flame retardant, the fire extinguishing efficiency is remarkably improved, reburning is inhibited, in addition, nano silicon dioxide is uniformly dispersed after being subjected to surface modification to form a compact heat insulation layer, the degradable surfactant and the environment-friendly preservative are combined, and the agent is free of toxic residues.

Description

Technical Field

[0001] The present invention belongs to the technical field of fire extinguishing agents, and particularly relates to a lithium battery fire extinguishing agent and a preparation method thereof. Background Art

[0002] Due to advantages such as high energy density and long cycle life, lithium batteries are widely used in fields such as electric vehicles and energy storage systems. However, lithium batteries are prone to thermal runaway under conditions such as overcharging, short circuit, or mechanical damage, leading to intense combustion or even explosion, and fire extinguishing agents are required for fire extinguishing.

[0003] Although traditional fire extinguishing agents can extinguish open flames, the internal chemical reactions of lithium batteries continuously release heat. Traditional fire extinguishing agents are difficult to block the thermal runaway chain reaction and cannot inhibit re-ignition, resulting in a high re-ignition rate. Summary of the Invention

[0004] The purpose of the present invention is to provide a lithium battery fire extinguishing agent and a preparation method thereof to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] The lithium battery fire extinguishing agent contains the following components by mass percentage:

[0007] Deionized water 60%-85%;

[0008] Degradable surfactant 5%-15%, selected from at least one of alkyl glycoside and fatty acid methyl ester sulfonate;

[0009] Nanoscale silica particles 0.1%-2%, with a particle size of 10-100 nm;

[0010] Composite flame retardant 3%-10%, compounded from an organophosphorus compound and graphene oxide in a mass ratio of 1:0.5-2;

[0011] Antifreeze 3%-8%, selected from at least one of ethylene glycol and propylene glycol;

[0012] Thickener 0.5%-3%, selected from at least one of xanthan gum and sodium carboxymethyl cellulose;

[0013] Preservative 0.1%-0.5%, selected from at least one of sodium benzoate and potassium sorbate.

[0014] Preferably, the nanoscale silica particles are modified with a silane coupling agent, and hydroxyl or amino functional groups are grafted on the surface.

[0015] The preparation method of the lithium battery fire extinguishing agent includes the following steps:

[0016] S1. Heat deionized water to 40 - 60 °C, add a biodegradable surfactant, and stir at 300 - 500 rpm for 10 - 20 minutes until completely dissolved;

[0017] S2. Add nanoscale silica particles, and treat them with an ultrasonic dispersion device for 20 - 40 minutes. The ultrasonic frequency is 20 - 50 kHz, and the power is 500 - 1000 W;

[0018] S3. Add a composite flame retardant, an antifreeze, a thickener, and a preservative in sequence, and continue to stir for 30 - 60 minutes until evenly mixed;

[0019] S4. Adjust the pH of the mixed solution to 7.5 - 8.5 through an online pH detector, and use a viscometer to control the final viscosity to be 50 - 200 mPa·s;

[0020] S5. After filtering through a 0.45 μm microporous filter membrane, obtain the fire extinguishing agent, fill it into a pressure-resistant container, and seal it for storage.

[0021] Preferably, the ultrasonic dispersion process in step S2 is carried out in an inert gas atmosphere.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) Through the synergistic effect of the composite flame retardant, the fire extinguishing efficiency is significantly improved and re - ignition is inhibited. In addition, after surface modification, the nano - silica is evenly dispersed to form a dense heat - insulating layer. Combined with the biodegradable surfactant and the environmental - friendly preservative, there is no toxic residue in the agent.

[0024] (2) It has both wide - temperature - range adaptability and long - term stability. The optimized compounding of the antifreeze and the thickener enables it to maintain fluidity in the environment of - 20 °C to 80 °C, without crystallization or stratification. The preparation process uses ultrasonic dispersion and inert gas protection to ensure the long - term suspension of nano - particles and improve stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the process flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1:

[0028] Please refer to Figure 1As shown, the lithium battery fire extinguishing agent contains the following components by mass percentage:

[0029] Deionized water 75%, biodegradable surfactant (alkyl polyglycoside) 10%, nano-scale silica particles (modified with silane coupling agent, surface grafted with hydroxyl functional groups, particle size 30nm) 1%, composite flame retardant (organic phosphorus compound and graphene oxide compounded at a mass ratio of 1:1) 6%, antifreeze (ethylene glycol) 5%, thickening agent (xanthan gum) 2%, preservative (sodium benzoate) 0.3%;

[0030] The preparation method of the lithium battery fire extinguishing agent includes the following steps:

[0031] S1. Dissolve the surfactant: Heat the deionized water to 50°C, add alkyl polyglycoside, and stir at 400 rpm for 15 minutes until completely dissolved.

[0032] S2. Disperse the nanoparticles: Under a nitrogen atmosphere, add the modified nano-silica particles to the solution, and use an ultrasonic dispersion device (frequency 40 kHz, power 800 W) to process for 30 minutes to ensure uniform dispersion of the particles;

[0033] S3. Add other components: Add the composite flame retardant, ethylene glycol, xanthan gum, and sodium benzoate in sequence, and continue to stir at 400 rpm for 45 minutes until the mixture is uniform;

[0034] S4. Adjust the pH and viscosity: Adjust the pH of the mixture to 8.0 through an on-line pH detector, and use a viscometer to control the final viscosity to 120 mPa·s;

[0035] S5. Filter and fill: Filter the mixture through a 0.45 μm microporous membrane, and then fill it into a pressure-resistant container and seal it for storage.

[0036] Example 2:

[0037] The lithium battery fire extinguishing agent contains the following components by mass percentage:

[0038] Deionized water 65%, biodegradable surfactant (fatty acid methyl ester sulfonate) 12%, nano-scale silica particles (surface grafted with amino functional groups, particle size 50nm) 1.5%, composite flame retardant (organic phosphorus compound and graphene oxide compounded at a mass ratio of 1:1.5) 8%, antifreeze (propylene glycol) 8%, thickening agent (sodium carboxymethyl cellulose) 2.5%, preservative (potassium sorbate) 0.5%;

[0039] The preparation method of the lithium battery fire extinguishing agent includes the following steps:

[0040] Dissolution and dispersion: Under a nitrogen atmosphere, deionized water was heated to 45 °C, fatty acid methyl ester sulfonate was added, and after stirring to dissolve, modified nano-silica particles were added, followed by ultrasonic treatment for 40 minutes (frequency 30 kHz, power 700 W); Mixing and adjustment: Other components were added in sequence, stirred for 50 minutes, and the pH was adjusted to 7.8, with a final viscosity of 180 mPa·s;

[0041] Filling and testing: After filtration, it was filled and subjected to a low-temperature stability test at -20 °C. The results showed that there was no crystallization or solidification of the agent, and the fluidity remained good, being suitable for extremely low-temperature environments.

[0042] Experimental examples:

[0043] A control group, experimental group 1, and experimental group 2 were designed. The control group had a flame retardant ratio of 1:1 (organic phosphorus compound: graphene oxide), experimental group 1 had a ratio of 1:1.5, and experimental group 2 had a ratio of 1:2. The other components were the same as in Example 1 (75% deionized water, 10% surfactant, etc.);

[0044] Testing methods

[0045] Fire extinguishing time: Simulating the thermal runaway scenario of lithium batteries (UL 9540A standard), recording the time required for the agent to completely suppress the flame;

[0046] Heat release rate (HRR): Using a cone calorimeter (ISO 5660-1), with a heat radiation intensity of 50 kW / m 2 ;

[0047] Limiting oxygen index (LOI): According to the ASTM D2863 standard, determining the minimum oxygen concentration required for material combustion;

[0048] Thermogravimetric analysis (TGA): Under a nitrogen atmosphere, with a heating rate of 10 °C / min, determining the decomposition temperature;

[0049] The following table shows the performance comparison under different flame retardant ratios:

[0050]

[0051]

[0052] As can be seen from the above, the fire extinguishing time of the ratio of 1:2 is shortened by 26.4% compared with the control group, indicating a significant improvement in the flame retardant efficiency; the peak value of HRR is reduced by 32.4%, and the total heat release is reduced by 26.3%, indicating that the lamellar structure of graphene oxide effectively isolates heat transfer; the LOI is increased from 28.5% to 34.0%, reaching the level of "flame retardant material" (LOI > 30%); the decomposition temperature is increased to 318 °C, indicating that the agent can still maintain a stable structure at high temperatures. When the flame retardant ratio is 1:2, the comprehensive flame retardant performance of the agent is the best, meeting the rapid suppression requirements of high energy density lithium battery fires.

[0053] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Lithium battery fire extinguishing agent, characterized in that, By mass percentage, it contains the following components: Deionized water 60%-85%; Degradable surfactant 5%-15%, selected from at least one of alkyl glycoside and fatty acid methyl ester sulfonate; Nanoscale silica particles 0.1%-2%, with a particle size of 10-100 nm; Composite flame retardant 3%-10%, compounded from an organophosphorus compound and graphene oxide in a mass ratio of 1:0.5-2; Antifreeze 3%-8%, selected from at least one of ethylene glycol and propylene glycol; Thickener 0.5%-3%, selected from at least one of xanthan gum and sodium carboxymethyl cellulose; Preservative 0.1%-0.5%, selected from at least one of sodium benzoate and potassium sorbate.

2. The lithium battery fire extinguishing agent according to claim 1, wherein: The nanoscale silica particles are modified with a silane coupling agent, and hydroxyl or amino functional groups are grafted on the surface.

3. Preparation method of lithium battery fire extinguishing agent, characterized in that, It includes the following steps: S1. Heat the deionized water to 40-60 °C, add the degradable surfactant, and stir at 300-500 rpm for 10-20 minutes until completely dissolved; S2. Add the nanoscale silica particles, and treat them with an ultrasonic dispersion device for 20-40 minutes, with an ultrasonic frequency of 20-50 kHz and a power of 500-1000 W; S3. Sequentially add the composite flame retardant, antifreeze, thickener and preservative, and continue to stir for 30-60 minutes until evenly mixed; S4. Adjust the pH of the mixed solution to 7.5-8.5 through an online pH detector, and control the final viscosity to be 50-200 mPa·s with a viscometer; S5. After filtering through a 0.45 μm microporous membrane, a fire extinguishing agent is obtained, filled into a pressure-resistant container, and sealed for storage.

4. The lithium battery fire extinguishing agent and its preparation method according to claim 3, characterized in that: The ultrasonic dispersion process in step S2 is carried out in an inert gas atmosphere.

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