Method for preparing fireproof heat-resistant coating, fireproof heat-resistant coating and battery

Abstract

The application provides a preparation method of fireproof heat-resistant paint, fireproof heat-resistant paint and a battery, and particularly relates to the technical field of paint. The preparation method of the fireproof heat-resistant paint comprises the following steps: adding silica gel particle powder, a high-molecular polymer and mesoporous honeycomb-shaped aluminum hydroxide into a solvent, and stirring uniformly to obtain the fireproof heat-resistant paint. The fireproof heat-resistant paint prepared by the preparation method has the mesoporous honeycomb-shaped aluminum hydroxide with rich pore structures and a large specific surface area, so that the heat in the combustion process is reduced, and heat transfer and flame propagation are prevented. Moreover, the aluminum hydroxide is decomposed to release water under heat, absorbs heat to reduce the system temperature, and the generated aluminum oxide is a refractory material, which is covered near the battery to improve the ability to resist flames, so that the purpose of preventing combustion by isolating air is achieved, and more serious accidents are prevented. The silica gel particle is compounded with the mesoporous honeycomb-shaped aluminum hydroxide, so that the performance of the fireproof heat-resistant paint is improved, and the fire-retardant effect is improved.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a method for preparing a fire-retardant and heat-resistant coating, the fire-retardant and heat-resistant coating, and a battery. Background Technology

[0002] Lithium-ion batteries have stood out among chemical energy storage devices due to their advantages such as high energy density, no memory effect, long cycle life, and environmental friendliness, attracting widespread attention from industries such as electric vehicles and 3C products. To meet market demand for high-energy-storage batteries, battery energy density is increasing, but safety issues are also becoming more prominent. Most battery cells improve thermal spread by doping and coating the positive and negative electrode materials and adding flame-retardant additives to the electrolyte; however, these methods are time-consuming and costly.

[0003] Applying an insulating and thermally conductive coating to the inner surface of the battery casing is also a way to prevent heat spread. However, the thermal insulation materials used in existing insulating and thermally conductive coatings, such as mica sheets, are not very effective and cannot immediately block the rapid thermal eruption of the battery cell, which can easily lead to more serious safety accidents.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One of the objectives of this invention is to provide a method for preparing a fire-retardant and heat-resistant coating, which aims to solve the technical problem that existing heat insulation materials have poor performance after preparation and cannot immediately block the rapid thermal eruption of the battery cell, which can easily lead to more serious safety accidents.

[0006] The second objective of this invention is to provide a fire-retardant and heat-resistant coating.

[0007] The third objective of this invention is to provide a battery.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] The first aspect of the present invention provides a method for preparing a fire-retardant and heat-resistant coating, wherein silica gel particle powder, a polymer and mesoporous honeycomb aluminum hydroxide are added to a solvent and stirred evenly to obtain the fire-retardant and heat-resistant coating.

[0010] Furthermore, by mass parts, the amount of silica gel particles is 20-50 parts, the amount of solvent is 40-100 parts, the amount of polymer is 30-60 parts, and the amount of mesoporous honeycomb aluminum hydroxide is 20-40 parts.

[0011] Furthermore, the method for preparing the mesoporous honeycomb aluminum hydroxide is as follows:

[0012] Soluble aluminum salts are added to an alcohol-water solution of ZIF-8, and the mixture is stirred, centrifuged, and washed to obtain a semi-finished product. Finally, the semi-finished product is dried to obtain mesoporous honeycomb aluminum hydroxide.

[0013] In the alcohol-water solution, the volume ratio of alcohol to water is 0.8-1.2:1.

[0014] Furthermore, the preparation method of ZIF-8 is as follows:

[0015] Zinc nitrate and dimethylimidazole were added to separate flasks, ethylene glycol was added and stirred, and then allowed to stand. A white precipitate appeared. Finally, the precipitate was filtered through a filter screen to obtain a white powder. The white powder was calcined in a muffle furnace to obtain ZIF-8.

[0016] Furthermore, the concentration of the ZIF-8 aqueous alcohol solution is 0.01 g / mL to 0.1 g / mL.

[0017] Furthermore, the aqueous alcohol solution of ZIF-8 includes an aqueous ethanol solution of ZIF-8, an aqueous methanol solution of ZIF-8, or an aqueous propanol solution of ZIF-8.

[0018] Furthermore, the soluble aluminum salt includes at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, and aluminum acetate;

[0019] The amount of the soluble aluminum salt added is 1.5 to 5 times the mass of ZIF-8.

[0020] Furthermore, the polymer comprises at least one of PVDF, PEO, and PVA.

[0021] Furthermore, the solvent includes at least one of methanol, ethanol, or propanol.

[0022] A second aspect of the present invention provides a fire-retardant and heat-resistant coating, which is prepared by the preparation method described in the first aspect.

[0023] A third aspect of the present invention provides a battery, including a cell, a casing, and a top cover;

[0024] The inner surface of the housing is provided with a fire-resistant and heat-resistant coating;

[0025] The fire-resistant and heat-resistant coating is formed by applying the fire-resistant and heat-resistant coating described in the second aspect.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] The fire-retardant and heat-resistant coating preparation method provided by this invention involves adding silica gel particle powder, a polymer, and mesoporous honeycomb aluminum hydroxide to a solvent and stirring until homogeneous. The preparation method is simple, highly mechanized, and allows for large batch processing, making it suitable for large-scale industrial production.

[0028] The fire-retardant and heat-resistant coating provided by this invention comprises mesoporous honeycomb aluminum hydroxide, which has abundant pore structure and a large specific surface area, reducing the heat during combustion and preventing heat transfer and flame propagation. Furthermore, the aluminum hydroxide decomposes upon heating, releasing moisture and absorbing heat to lower the system temperature; simultaneously, the resulting alumina is a refractory material that, when applied near the battery cell, enhances its resistance to flames, effectively isolating it from air and preventing combustion, thus preventing more serious accidents. The use of silica gel particles in combination with mesoporous honeycomb aluminum hydroxide synergistically improves the performance of the fire-retardant and heat-resistant coating, enhancing its flame-retardant effect.

[0029] The battery provided by this invention has better flame retardant effect, ensures the safe life of the battery, and expands the development of downstream industries. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. The components of the embodiments of this invention can be arranged and designed in various different configurations.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] The first aspect of the present invention provides a method for preparing a fire-retardant and heat-resistant coating, wherein silica gel particle powder, a polymer and mesoporous honeycomb aluminum hydroxide are added to a solvent and stirred evenly to obtain the fire-retardant and heat-resistant coating.

[0033] The fire-retardant and heat-resistant coating preparation method provided by this invention involves adding silica gel particle powder, a polymer, and mesoporous honeycomb aluminum hydroxide to a solvent and stirring until homogeneous. The preparation method is simple, highly mechanized, and allows for large batch processing, making it suitable for large-scale industrial production.

[0034] Furthermore, by mass parts, the amount of silica gel particles is 20-50 parts, the amount of solvent is 40-100 parts, the amount of polymer is 30-60 parts, and the amount of mesoporous honeycomb aluminum hydroxide is 20-40 parts.

[0035] Typically, but not limitingly, the mass fractions of silica gel particles can be 20, 25, 30, 35, 40, 45, or 50; the mass fractions of solvent can be 40, 50, 60, 70, 80, 90, or 100; the mass fractions of polymer can be 30, 35, 40, 45, 50, 55, or 60; and the mass fractions of mesoporous honeycomb aluminum hydroxide can be 20, 25, 30, 35, or 40.

[0036] Furthermore, the method for preparing the mesoporous honeycomb aluminum hydroxide is as follows:

[0037] Soluble aluminum salts were added to an alcohol-water solution of ZIF-8, and the mixture was stirred, centrifuged, and washed to obtain a semi-finished product. Finally, the semi-finished product was dried to obtain mesoporous honeycomb aluminum hydroxide. In this preparation method, ZIF-8 was used as a self-sacrificing template, and mesoporous honeycomb aluminum hydroxide with a ZIF-8 cavity structure was synthesized by template-directed method.

[0038] In the alcohol-water solution, the volume ratio of alcohol to water is 0.8-1.2:1. Typically, but not limitingly, the volume ratio of alcohol to water in the alcohol-water solution can be 0.8:1, 0.9:1, 1:1, 1.1:1, or 1.2:1.

[0039] Furthermore, the preparation method of ZIF-8 is as follows:

[0040] Zinc nitrate and dimethylimidazole were added to separate flasks, ethylene glycol was added and stirred, and then allowed to stand. A white precipitate appeared. Finally, the precipitate was filtered through a filter screen to obtain a white powder. The white powder was calcined in a muffle furnace to obtain ZIF-8.

[0041] Furthermore, the concentration of the ZIF-8 alcohol-water solution is 0.01 g / mL to 0.1 g / mL, preferably 0.03 g / mL to 0.06 g / mL.

[0042] The concentration of the alcohol-water solution of ZIF-8 is in the range of 0.01 g / mL to 0.1 g / mL, which can ensure that ZIF-8 is uniformly dispersed in the system.

[0043] Typical, but not limiting, concentrations of the aqueous alcoholic solution of ZIF-8 can be, for example, 0.01 g / mL, 0.02 g / mL, 0.03 g / mL, 0.04 g / mL, 0.05 g / mL, 0.06 g / mL, 0.07 g / mL, 0.08 g / mL, 0.09 g / mL, or 0.1 g / mL.

[0044] Furthermore, the aqueous alcohol solution of ZIF-8 includes an aqueous ethanol solution of ZIF-8, an aqueous methanol solution of ZIF-8, or an aqueous propanol solution of ZIF-8.

[0045] Furthermore, the soluble aluminum salt includes at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, and aluminum acetate;

[0046] The amount of soluble aluminum salt added is 1.5 to 5 times the mass of ZIF-8. If the amount of soluble aluminum salt added is less than 1.5 times the mass of ZIF-8, it will affect the dissolution and bonding of ZIF-8 with it, resulting in an impure material and a reduced specific surface area. If the amount of soluble aluminum salt added is more than 5 times the mass of ZIF-8, an ideal material cannot be obtained, and the specific surface area is also reduced. Typically, but not limitingly, the amount of soluble aluminum salt added can be, for example, 1.5, 2, 3, 4, or 5 times the mass of ZIF-8.

[0047] Furthermore, the polymer includes at least one of PVDF, PEO, and PVA. As a resin for coatings, the aforementioned polymer has advantages such as high plasticity, ease of processing, high heat resistance, and high mechanical strength. The weight percentage of the polymer is controlled between 30 and 60 parts; a percentage greater than 60 parts affects processability and causes the coating to solidify; a percentage less than 30 parts is detrimental to adhesion.

[0048] Furthermore, the solvent includes at least one of methanol, ethanol, or propanol.

[0049] A second aspect of the present invention provides a fire-retardant and heat-resistant coating, which is prepared by the preparation method described in the first aspect.

[0050] The fire-retardant and heat-resistant coating provided by this invention comprises mesoporous honeycomb aluminum hydroxide, which has abundant pore structure and a large specific surface area, reducing the heat during combustion and preventing heat transfer and flame propagation. Furthermore, the aluminum hydroxide decomposes upon heating, releasing moisture and absorbing heat to lower the system temperature; simultaneously, the resulting alumina is a refractory material that, when applied near the battery cell, enhances its resistance to flames, effectively isolating it from air and preventing combustion, thus preventing more serious accidents. The use of silica gel particles in combination with mesoporous honeycomb aluminum hydroxide synergistically improves the performance of the fire-retardant and heat-resistant coating, enhancing its flame-retardant effect.

[0051] A third aspect of the present invention provides a battery, including a cell, a casing, and a top cover;

[0052] The inner surface of the housing is provided with a fire-resistant and heat-resistant coating;

[0053] The fire-resistant and heat-resistant coating is formed by applying the fire-resistant and heat-resistant coating described in the second aspect.

[0054] The battery provided by this invention has better flame retardant effect, ensures the safe life of the battery, and expands the development of downstream industries.

[0055] The following detailed description of some embodiments of the present invention is provided in conjunction with examples. Unless otherwise specified, the following embodiments and features can be combined with each other. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples were all commercially available.

[0056] The ZIF-8 used in the embodiments and comparative examples of this invention is a self-made product, prepared by a water bath method. The specific steps are as follows: 0.2g of zinc nitrate and 11g of dimethylimidazole are added to a flask, 55mL of ethylene glycol is added and stirred for 1.5 hours, and then allowed to stand for 14 hours. A white precipitate appears. Finally, it is filtered through a filter screen to obtain a white powder. The white powder is calcined in a muffle furnace at 500℃ for 2 hours to obtain ZIF-8.

[0057] Example 1

[0058] This embodiment provides a mesoporous honeycomb aluminum hydroxide, prepared by the following method:

[0059] 1. Add 2.5g of ZIF-8 to 55mL of ethanol-water solution (ethanol to water volume ratio of 1:1), stir vigorously to obtain a white suspension.

[0060] 2. Add 7g Al(NO3)3·9H2O to the white suspension, stir continuously for 45min, collect by centrifugation, and rinse thoroughly with ethanol. Finally, dry the product in an oven at 80℃ overnight to obtain mesoporous honeycomb aluminum hydroxide.

[0061] Example 2

[0062] This embodiment provides a mesoporous honeycomb aluminum hydroxide, prepared by the following method:

[0063] 1. Add 2g of ZIF-8 to 50mL of ethanol-water solution (ethanol to water volume ratio of 1:1), stir vigorously to obtain a white suspension.

[0064] 2. Add 6g Al(NO3)3·9H2O to the white suspension, stir continuously for 45min, collect by centrifugation, and rinse thoroughly with ethanol. Finally, dry the product in an oven at 80℃ overnight to obtain mesoporous honeycomb aluminum hydroxide.

[0065] Example 3

[0066] This embodiment provides a mesoporous honeycomb aluminum hydroxide, prepared by the following method:

[0067] 1. Add 3g of ZIF-8 to 60mL of ethanol-water solution (ethanol to water volume ratio of 1:1), stir vigorously to obtain a white suspension.

[0068] 2. Add 8g of Al(NO3)3·9H2O to the white suspension, stir continuously for 60min, collect by centrifugation, and rinse thoroughly with ethanol. Finally, dry the product in an oven at 80℃ overnight to obtain mesoporous honeycomb aluminum hydroxide.

[0069] Example 4

[0070] This embodiment provides a mesoporous honeycomb aluminum hydroxide. The difference from Example 1 is that the mass of Al(NO3)3·9H2O added in step 2 is 3.8g. The other raw materials and methods are the same as in Example 1, and will not be repeated here.

[0071] Example 5

[0072] This embodiment provides a mesoporous honeycomb aluminum hydroxide. The difference from Example 1 is that the mass of Al(NO3)3·9H2O added in step 2 is 12.5g. The other raw materials and methods are the same as in Example 1, and will not be repeated here.

[0073] Example 6

[0074] This embodiment provides a mesoporous honeycomb aluminum hydroxide. The difference from Example 1 is that the mass of Al(NO3)3·9H2O added in step 2 is 2.5g. The other raw materials and methods are the same as in Example 1, and will not be repeated here.

[0075] Example 7

[0076] This embodiment provides a mesoporous honeycomb aluminum hydroxide. The difference from Example 1 is that the mass of Al(NO3)3·9H2O added in step 2 is 15g. The other raw materials and methods are the same as in Example 1, and will not be repeated here.

[0077] Examples 8-14

[0078] This embodiment provides a fire-retardant and heat-resistant coating, the preparation method of which is as follows:

[0079] 1. Add 4g of silica gel granules (Aladdin) and 5g of PVDF polymer to 7ml of ethanol and stir evenly at 85℃.

[0080] 2. Add 3g of the mesoporous honeycomb aluminum hydroxide provided in Examples 1-7 to the mixture obtained in step 1 and mix evenly to obtain the fireproof and heat-resistant coating.

[0081] Example 15

[0082] This embodiment provides a fireproof and heat-resistant coating. The difference from embodiment 8 is that the amount of mesoporous honeycomb aluminum hydroxide added is 2g. The other raw materials and methods are the same as in embodiment 8, and will not be repeated here.

[0083] Example 16

[0084] This embodiment provides a fireproof and heat-resistant coating. The difference from embodiment 8 is that the amount of mesoporous honeycomb aluminum hydroxide added is 4g. The other raw materials and methods are the same as in embodiment 8, and will not be repeated here.

[0085] Example 17

[0086] This embodiment provides a fireproof and heat-resistant coating. The difference from embodiment 8 is that the amount of mesoporous honeycomb aluminum hydroxide added is 0.5g. The other raw materials and methods are the same as in embodiment 8, and will not be repeated here.

[0087] Example 18

[0088] This embodiment provides a fireproof and heat-resistant coating. The difference from embodiment 8 is that the amount of mesoporous honeycomb aluminum hydroxide added is 8g. The other raw materials and methods are the same as in embodiment 8, and will not be repeated here.

[0089] Comparative Example 1

[0090] This comparative example provides a fire-retardant and heat-resistant coating. Unlike Example 8, conventional aluminum hydroxide (purity 99.8%; average particle size 10 μm; manufacturer: Aladdin) is used instead of mesoporous honeycomb aluminum hydroxide. All other raw materials and methods are the same as in Example 8, and will not be repeated here.

[0091] Comparative Example 2

[0092] This comparative example provides a fire-retardant and heat-resistant coating. Unlike Example 8, it does not contain mesoporous honeycomb aluminum hydroxide. All other raw materials and methods are the same as in Example 8, and will not be repeated here.

[0093] Comparative Example 3

[0094] This comparative example provides a fire-retardant and heat-resistant coating. Unlike Example 8, it does not contain silica gel powder. All other raw materials and methods are the same as in Example 8, and will not be repeated here.

[0095] Experimental Example 1

[0096] The fire-retardant and heat-resistant coatings provided in Examples 8-18 and Comparative Examples 1-3 were applied to the inside of the aluminum shell using a scraper. The coating thickness was 100 μm. After completion, the coating was assembled with the battery cell and thermal runaway test was performed.

[0097] The specific thermal runaway test steps are as follows: fully charge the battery cell, place a 1000W heating plate at the center of the side of the battery cell, and observe the time it takes for the battery cell to open the valve and emit smoke and flames during thermal runaway. The data obtained are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] As can be seen from Table 1, the amount of aluminum nitrate added in Example 13 was too small, and the amount of aluminum nitrate added in Example 14 was more than 5 times the normal amount. Both too much and too little aluminum nitrate will affect the thermal runaway time of the battery cell. The thermal runaway of the battery cell in Example 7 showed the worst effect. It can be seen from Examples 15-18 that the more mesoporous aluminum hydroxide is added, the more obvious the thermal runaway effect of the battery cell is, and the mesoporous aluminum hydroxide is better than conventional aluminum hydroxide. The data from Example 8 and Comparative Example 3 show that the addition of silicon dioxide further improved the safety performance of the battery cell.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery, characterized in that, Includes battery cells, casing, and top cover; The inner surface of the housing is provided with a fire-resistant and heat-resistant coating; the fire-resistant and heat-resistant coating is formed by applying a fire-resistant and heat-resistant paint. The method for preparing the fire-retardant and heat-resistant coating involves adding 20-50 parts of silica gel particle powder, 30-60 parts of polymer, and 20-40 parts of mesoporous honeycomb aluminum hydroxide to 40-100 parts of solvent, and stirring until uniform to obtain the fire-retardant and heat-resistant coating; the polymer includes at least one of PVDF, PEO, and PVA. The solvent includes at least one of methanol, ethanol, or propanol; The method for preparing the mesoporous honeycomb aluminum hydroxide is as follows: soluble aluminum salt is added to an alcohol-water solution of ZIF-8, and the mixture is stirred, centrifuged, and washed to obtain a semi-finished product. Finally, the semi-finished product is dried to obtain mesoporous honeycomb aluminum hydroxide. In the alcohol-water solution, the volume ratio of alcohol to water is 0.8-1.2:

1.

2. The battery according to claim 1, characterized in that, The preparation method of ZIF-8 is as follows: Zinc nitrate and dimethylimidazole were added to separate flasks, ethylene glycol was added and stirred, and then allowed to stand. A white precipitate appeared. Finally, the precipitate was filtered through a filter screen to obtain a white powder. The white powder was calcined in a muffle furnace to obtain ZIF-8.

3. The battery according to claim 1, characterized in that, The concentration of the ZIF-8 aqueous alcohol solution is 0.01 g / mL to 0.1 g / mL.

4. The battery according to claim 1, characterized in that, The ZIF-8 aqueous solution includes an aqueous solution of ZIF-8 in ethanol, an aqueous solution of ZIF-8 in methanol, or an aqueous solution of ZIF-8 in propanol.

5. The battery according to claim 1, characterized in that, The soluble aluminum salt includes at least one of aluminum nitrate, aluminum chloride, aluminum sulfate, and aluminum acetate; The amount of the soluble aluminum salt added is 1.5 to 5 times the mass of ZIF-8.

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