Battery fire extinguishing material based on vermiculite modification and preparation method thereof

Abstract

The present application relates to a kind of battery fire extinguishing material based on vermiculite modification and its preparation method, the battery fire extinguishing material is specifically prepared by modifying vermiculite after compounding inorganic salt solution, wherein, compounding inorganic salt solution is composed of NaHCO3 and KCl.The preparation method includes the following steps: vermiculite is washed with distilled water multiple times;Vermiculite is placed in the prepared compounding inorganic salt solution with set concentration at room temperature to modify operation, and modified vermiculite is obtained;Modified vermiculite is heated, and then cooled to obtain expanded modified vermiculite, i.e.the battery fire extinguishing material.Compared with prior art, the present application modifies vermiculite by compounding solution of NaHCO3 and KCl with certain concentration, and the modified vermiculite contains Na+ and K+ at the same time, which is more conducive to eliminating flame free radicals through compounding synergistic effect, and after the battery is heated, the sprayed modified vermiculite expands rapidly, which can effectively block the contact between battery and air, and play a better fire extinguishing role.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery fire extinguishing materials technology, and in particular to a battery fire extinguishing material based on vermiculite modification and its preparation method. Background Technology

[0002] With the development of lithium-ion battery energy storage technology, lithium-ion battery energy storage power stations have gradually become an important component of the power grid's generation, transmission, transformation, distribution, and utilization processes. However, after a period of operation, the performance of lithium-ion batteries in energy storage power stations gradually becomes inconsistent. The increase in battery internal resistance increases the risk of thermal runaway, potentially causing serious fire accidents and affecting the safe operation of the energy storage power station. To minimize personal injury and property damage caused by lithium-ion battery fires, the development and application of efficient lithium-ion battery fire extinguishing materials are crucial for solving the safety problems of energy storage power stations.

[0003] Conventional battery fire extinguishing methods primarily involve spraying water or sand onto the burning battery to extinguish the fire. However, due to the presence of active materials and flammable organic electrolytes inside the battery, these traditional methods are often ineffective in extinguishing fires promptly. Vermiculite, a hydrated magnesium aluminum silicate mineral, expands significantly when heated. The expanded vermiculite has a compact structure but low density and low thermal conductivity, making it an excellent heat-insulating fire extinguishing material. Because of its high-temperature resistance and good thermal stability, vermiculite is widely used in chemical, metallurgical, and construction industries. To further improve the heat-insulating and fire-extinguishing performance of vermiculite, modification to increase its expansion coefficient at high temperatures is key to developing highly efficient vermiculite fire extinguishing materials.

[0004] In the prior art, Chinese patent CN201810615992.7 discloses a method for preparing modified vermiculite for refractory materials. The method involves soaking vermiculite powder in a 1 mol / L magnesium chloride solution for modification, followed by drying in an oven. The modified vermiculite expands faster, resulting in better fire resistance. However, this method only considers the modification of vermiculite with magnesium chloride solution and is not suitable for fire extinguishing in the battery field.

[0005] Chinese patent CN201610907607.7 discloses a method for preparing expanded vermiculite, which includes: soaking vermiculite in 0.1–1 mol / L solutions of potassium nitrate, potassium chloride, magnesium nitrate, magnesium chloride, and oxalic acid, respectively; filtering out the solutions from the soaked vermiculite; drying the soaked vermiculite; and then heating it at 90–550°C for several minutes to obtain expanded vermiculite. However, this method does not show the changes in the modified vermiculite and does not consider the influence of vermiculite particle size on the modification effect. Therefore, the practical application effect of this method needs further verification.

[0006] Furthermore, Chinese patent CN202210826681.1 discloses a method for preparing a vermiculite-based composite flame retardant material. The vermiculite-based composite flame retardant material includes vermiculite, carbon nanotubes, boron phosphate, and tin hydroxide. The combination of multiple flame retardants constructs a high-performance, three-dimensional flame retardant. By growing carbon nanotubes on vermiculite layers and using a co-precipitation method, an intercalated, multi-level structured flame retardant is constructed, thus achieving the preparation of a composite flame retardant material. However, the modification experiments of the composite materials in this method are quite complex, the carbon nanotubes significantly increase the cost of the flame retardant material, and the selection of composite materials is not conducive to large-scale preparation and application. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a battery fire extinguishing material based on vermiculite modification and its preparation method, which can further improve the expansion coefficient of vermiculite at high temperatures and enable large-scale preparation and application.

[0008] The objective of this invention can be achieved through the following technical solution: a battery fire extinguishing material based on vermiculite modification, specifically prepared by modifying vermiculite with a compound inorganic salt solution.

[0009] Furthermore, the compound inorganic salt solution is composed of NaHCO3 and KCl.

[0010] A method for preparing a battery fire extinguishing material based on vermiculite modification includes the following steps:

[0011] S1. Wash the vermiculite several times with distilled water;

[0012] S2. At room temperature, vermiculite is placed in a prepared compound inorganic salt solution of a set concentration for modification to obtain modified vermiculite;

[0013] S3. The modified vermiculite is heated and then cooled to obtain expanded modified vermiculite, which is the battery fire extinguishing material.

[0014] Furthermore, the compound inorganic salt solution of the set concentration is specifically prepared by mixing NaHCO3 and KCl in a concentration ratio of 1:1.

[0015] Furthermore, the modification operation in step S2 includes stirring, replacing with a fresh compound inorganic salt solution, and removing the solution, drying, and grinding.

[0016] Furthermore, step S2 specifically includes the following steps:

[0017] S21. At room temperature, place vermiculite into a prepared compound inorganic salt solution of a set concentration and stir. Replace the solution with fresh compound inorganic salt solution at set time intervals and stir again. Repeat this step N times.

[0018] S22. After soaking, the vermiculite is removed from the solution, dried, and then ground to obtain modified vermiculite with a set particle size.

[0019] Furthermore, step S21 specifically involves using a magnetic stirrer to perform a stirring operation at a set speed.

[0020] Furthermore, step S3 specifically involves placing the modified vermiculite into a tube furnace for heating.

[0021] Furthermore, step S3 specifically includes the following steps:

[0022] S31. Place the modified vermiculite into a tube furnace, heat it at a constant temperature according to the set temperature, and continue heating for the set time.

[0023] S32. The modified vermiculite that has expanded after heating is removed from the tube furnace and cooled to room temperature to obtain expanded modified vermiculite.

[0024] Furthermore, the specific formula for calculating the expansion coefficient of the expanded modified vermiculite is as follows:

[0025]

[0026] ΔV=V2-V1

[0027] Δt=t2-t1

[0028] Where V1 is the volume of modified vermiculite at temperature t1 before heating, V2 is the volume of expanded modified vermiculite when the temperature rises to the set temperature t2 after heating, ΔV is the volume change before and after expansion, and Δt is the temperature change before and after expansion.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] This invention modifies vermiculite by compounding inorganic salt solutions, resulting in a higher expansion coefficient at high temperatures. The expanded modified vermiculite can more effectively isolate air and has a better fire extinguishing effect.

[0031] In this invention, the compound inorganic salt solution is composed of NaHCO3 and KCl. The modified vermiculite contains both Na+ and K+. Through the synergistic effect of the compound, it is more conducive to eliminating flame free radicals. After the battery catches fire and is heated, the sprayed modified vermiculite expands rapidly, thereby effectively blocking the battery from contacting the air and playing a better fire extinguishing role.

[0032] The preparation method proposed in this invention only requires placing vermiculite into a prepared compound inorganic salt solution of a set concentration for stirring, replacing the solution with fresh compound inorganic salt solution, and stirring again. After that, modified vermiculite with a set particle size can be obtained by removing the solution, drying, and grinding. After heating the modified vermiculite and then cooling it, expanded modified vermiculite can be obtained. The whole preparation process is simple and effective, and the compound inorganic salt material is easy to obtain and inexpensive, making it suitable for large-scale preparation and application. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the preparation method of the present invention;

[0034] Figure 2 The figures shown in the examples are the expansion coefficient curves of 0.4 mm particle size vermiculite in the temperature range of 100–900 °C, respectively, after modification with unmodified vermiculite, modified with 0.4 mol / L NaHCO3 solution, modified with 0.4 mol / L KCl solution, and modified with a compound solution of (0.2 mol / L NaHCO3 + 0.2 mol / L KCl).

[0035] Figure 3 The image shows a SEM image of the unmodified 0.4 mm vermiculite surface in the example.

[0036] Figure 4 The image shown is a SEM image of a 0.4 mm vermiculite surface modified with a 0.4 mol / L NaHCO3 solution in the example.

[0037] Figure 5 The image shown is a SEM image of a 0.4 mm vermiculite surface modified with a 0.4 mol / L KCl solution in the example.

[0038] Figure 6 The image shown is a SEM image of a 0.4 mm vermiculite surface modified with a (0.2 mol / L NaHCO3 + 0.2 mol / L KCl) compound solution in the example. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] Example

[0041] A battery fire extinguishing material based on vermiculite modification is prepared by modifying vermiculite with a compound inorganic salt solution, wherein the compound inorganic salt solution is composed of NaHCO3 and KCl.

[0042] The preparation method of the above-mentioned vermiculite-modified battery fire extinguishing material is as follows: Figure 1 As shown, it includes the following steps:

[0043] S1. Wash the vermiculite several times with distilled water;

[0044] S2. At room temperature, vermiculite is placed in a prepared compound inorganic salt solution of a set concentration for modification (including stirring, replacing with fresh compound inorganic salt solution, removing the solution, drying, and grinding) to obtain modified vermiculite.

[0045] S3. The modified vermiculite is heated and then cooled to obtain expanded modified vermiculite, which is the battery fire extinguishing material.

[0046] In this embodiment, the compound inorganic salt solution with a set concentration is specifically prepared by mixing NaHCO3 and KCl in a concentration ratio of 1:1.

[0047] The main steps in applying the above solution in practice are as follows:

[0048] Wash the vermiculite several times with distilled water and place it in an Erlenmeyer flask;

[0049] At room temperature, vermiculite is placed into a prepared compound inorganic salt solution of a certain concentration;

[0050] Stir the solution using a magnetic stirrer at a certain speed, replace the solution with fresh solution every few hours, and repeat this operation multiple times.

[0051] The soaked vermiculite was filtered to remove the solution, dried, and ground to obtain modified vermiculite with a certain particle size.

[0052] The modified vermiculite was placed in a tube furnace and heated to expand. The temperature control range of the tube furnace was 100–900°C.

[0053] After heating to a predetermined temperature, the temperature is kept constant for a certain period of time, and then cooled to room temperature to obtain expanded modified vermiculite.

[0054] In addition, the volume of expanded vermiculite can be measured using a graduated cylinder to calculate the expansion coefficient.

[0055]

[0056] ΔV=V2-V1

[0057] Δt=t2-t1

[0058] In the formula, V1 is the volume (mm³) at temperature t1 (°C). 3 V2 is the volume when the temperature rises to t2 (°C), ΔV is the volume change before and after expansion, and Δt is the temperature change before and after expansion.

[0059] To verify the effectiveness of this method, vermiculite was modified using 0.4 mol / L NaHCO3 solution, 0.4 mol / L KCl solution, and a mixture of 0.2 mol / L NaHCO3 and 0.2 mol / L KCl solution, and the expansion coefficients of the modified vermiculite were compared.

[0060] In this embodiment, the vermiculite is sourced from Weili County, Xinjiang, and its chemical formula is:

[0061] 22MgO·5Al2O3·Fe2O3·22SiO2·4H2O.

[0062] First, wash three equal portions of vermiculite three times with distilled water and place them in an Erlenmeyer flask;

[0063] Then, the prepared 0.4 mol / L NaHCO3 solution, 0.4 mol / L KCl solution, and 0.2 mol / L NaHCO3 and 0.2 mol / L KCl compound solution were poured into conical flasks and kept at a constant temperature of 25℃.

[0064] Use a magnetic stirrer at 160 rpm. -1 The solution was stirred in three conical flasks at a certain speed, and the inorganic salt solution was replaced with fresh solution every 4 hours. The above operation was repeated twice for each conical flask.

[0065] The solution was filtered out from the three soaked vermiculite samples, dried, and then ground to control the vermiculite particle size to 0.4 mm, resulting in three modified vermiculite samples.

[0066] At a temperature of t1 (°C), three portions of a certain amount of modified vermiculite powder were measured using a graduated cylinder, and their corresponding volumes V1 were recorded.

[0067] Three portions of modified vermiculite powder were loosely spread at the bottom of the crucible, and the crucible was placed in a tube furnace for heating. The temperature range set in the experiment was 100 to 900°C, with a temperature interval of 100°C.

[0068] After heating to a predetermined temperature t2 (°C), the temperature was maintained for 0.5 hours, followed by cooling to room temperature, yielding three portions of modified expanded vermiculite. The volumes of the three portions of expanded vermiculite were measured using a graduated cylinder, and the corresponding expansion coefficients were calculated. The formula for calculating the expansion coefficient is:

[0069]

[0070] ΔV=V2-V1

[0071] Δt=t2-t1

[0072] V1 is the volume (mm³) at temperature t1 (°C). 3V2 is the volume when the temperature rises to t2 (°C), ΔV is the volume change before and after expansion, and Δt is the temperature change before and after expansion.

[0073] Comparative analysis showed that the expansion coefficient of vermiculite modified with a 0.2 mol / L NaHCO3 and 0.2 mol / L KCl mixed solution was higher than that of vermiculite modified with 0.4 mol / L NaHCO3 or KCl alone, or even unmodified vermiculite. Figure 2 As shown. Compare again. Figures 3-6 It can be seen that the vermiculite modified with a 0.2 mol / L NaHCO3 and 0.2 mol / L KCl compound solution is more porous than that modified or unmodified with a 0.4 mol / L NaHCO3 or KCl single solution. Furthermore, the compound inorganic salt material is readily available, inexpensive, and simple to prepare. In addition, the modified vermiculite also contains Na... + K + Through the synergistic effect of compounding, it is more effective in eliminating flame free radicals. After the battery catches fire and is heated, the sprayed modified vermiculite expands rapidly, effectively blocking the battery from contacting the air, and can play a better role in extinguishing fire.

Claims

1. A battery fire extinguishing material based on vermiculite modification, characterized in that, Specifically, it is prepared by modifying vermiculite with a compound inorganic salt solution, which consists of NaHCO3 and KCl.

2. A method for preparing a battery fire extinguishing material based on vermiculite modification, characterized in that, Includes the following steps: S1. Wash the vermiculite several times with distilled water; S2. At room temperature, vermiculite is placed in a prepared compound inorganic salt solution with a set molar concentration for modification to obtain modified vermiculite. The compound inorganic salt solution with a set molar concentration is specifically prepared by NaHCO3 and KCl with a molar concentration ratio of 1:

1. S3. The modified vermiculite is heated and then cooled to obtain expanded modified vermiculite, which is the battery fire extinguishing material.

3. The method for preparing a battery fire extinguishing material based on vermiculite modification according to claim 2, characterized in that, The modification operation in step S2 includes stirring, replacing with fresh compound inorganic salt solution, and removing the solution, drying, and grinding.

4. The method for preparing a battery fire extinguishing material based on vermiculite modification according to claim 3, characterized in that, Step S2 specifically includes the following steps: S21. At room temperature, place vermiculite into a prepared compound inorganic salt solution of a set molar concentration and stir. Replace the solution with fresh compound inorganic salt solution at set time intervals and stir again. Repeat this step N times. S22. After soaking, the vermiculite is removed from the solution, dried, and then ground to obtain modified vermiculite with a set particle size.

5. The method for preparing a battery fire extinguishing material based on vermiculite modification according to claim 4, characterized in that, Specifically, step S21 involves using a magnetic stirrer to perform a stirring operation at a set speed.

6. The method for preparing a battery fire extinguishing material based on vermiculite modification according to claim 2, characterized in that, Specifically, step S3 involves placing the modified vermiculite into a tube furnace for heating.

7. The method for preparing a battery fire extinguishing material based on vermiculite modification according to claim 6, characterized in that, Step S3 specifically includes the following steps: S31. Place the modified vermiculite into a tube furnace, heat it at a constant temperature according to the set temperature, and continue heating for the set time. S32. The modified vermiculite that has expanded after heating is removed from the tube furnace and cooled to room temperature to obtain expanded modified vermiculite.

8. A method for preparing a battery fire extinguishing material based on vermiculite modification according to claim 7, characterized in that, The specific formula for calculating the expansion coefficient of the expanded modified vermiculite is as follows: , in, V 1 represents the temperature before heating. t The volume of modified vermiculite at 1 hour V 2. The temperature rises to the set temperature after heating. t The volume of expanded modified vermiculite at time 2, Δ V Let Δ be the volume change before and after expansion. t The temperature change before and after expansion.

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