Thermal-expansion heat-insulation flame-retardant battery coating as well as preparation method and application thereof
By modifying Elostone nanotubes to improve the thermal stability of the expanded carbon layer, the thermally expanded thermal insulation and flame retardant battery coating is prepared, which solves the problems of increased quality and low production efficiency of existing battery fire-retardant materials, achieves efficient thermal insulation and flame retardant effects, and extends the service life of the battery.
Patent Information
- Application Number
- CN202510244135.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-05-30
AI Technical Summary
The fire-resistant materials of existing new energy vehicle battery systems have problems such as increased quality, reduced heat dissipation performance and low production efficiency. The battery fire-resistant coating has not been independently developed in China according to the needs of the whole vehicle, and there are problems of insufficient reliability and adhesion.
By improving the thermal stability of the expanded carbon layer by modifying the Elostone nanotube, a thermally expanded thermally insulated and flame-retardant battery coating is prepared. The coating includes organic expanded flame retardant, matrix resin and modified Elostone nanotubes by mass fractions, and is prepared by mechanical high-speed stirring and automatic coating machine.
The coating can expand evenly at high temperatures, enhance the stability and consistency of the coating, reduce the damage to the battery's internal damage by high temperatures, reduce the risk of safety accidents caused by thermal runaway and combustion of the battery, and extend the battery's service life and cycle times.
Smart Images
Figure CN120059545A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of high-temperature resistant coatings, and particularly to a thermally expandable heat-insulating and flame-retardant battery coating, a preparation method thereof, and an application thereof. Background Art
[0002] At the current industrial level, the fireproof materials for new energy vehicle battery systems mainly consist of laying fireproof felt materials. Common fireproof felt materials include mica plates, ultra-fine glass wool, high-silica oxygen cotton felt, etc. Although fireproof felt materials can efficiently block the diffusion of heat, precisely control the spread direction of fire, and greatly delay the diffusion process of battery thermal runaway. However, adopting the fireproof felt solution also has certain drawbacks. On the one hand, it will increase the overall mass of the system and reduce the heat dissipation performance; on the other hand, the efficiency is also relatively low during the production and assembly process.
[0003] Flame-retardant coatings are important technical means to delay the combustion of combustible materials. They can endow the materials with flame-retardant properties without affecting other inherent properties of the materials, and can effectively solve the above problems. According to the fireproof form and composition, flame-retardant coatings can be divided into non-expandable fireproof coatings and expandable fireproof coatings, and have been widely used in many fields such as construction, cultural relics protection, and electricity.
[0004] For the flame-retardant treatment of lithium battery diaphragms, positive electrodes, and current collectors, different forms of coating treatments are also adopted. Different from traditional building fireproof coatings, the fireproof coatings used to solve a series of safety problems caused by thermal runaway in power batteries not only need to improve the safety of the battery system, but also should be capable of automated production to meet the specific requirements of different applications and achieve large-scale manufacturing.
[0005] Since the fireproof coatings for new energy vehicles are a new demand, most suppliers do not have mature products. Currently, it is mainly to improve building fireproof coatings. For example, SVT expandable flame-retardant fireproof coatings, which are two-component flame-retardant materials based on polyurethane. When exposed to an open flame or high temperature, the thin coating will instantaneously expand more than 25 times its own thickness, forming a heat-insulating barrier and preventing the spread of thermal runaway. However, its reliability and adhesion cannot meet the requirements of the battery system. At present, the battery fireproof coatings in China are still in the initial stage and have not been independently developed according to the requirements of the whole vehicle. Its production and manufacturing are very difficult. From the aspects of coating performance and coating utilization rate, there is still much room for improvement in its formula and manufacturability. Therefore, thermally expandable heat-insulating and flame-retardant battery coatings with flexibility and more convenient production and manufacturing have great market prospects in the future. Summary of the Invention
[0006] The object of the present invention is to provide a thermally expandable heat-insulating and flame-retardant battery coating, a preparation method thereof, and an application thereof, which improve the thermal stability of the expanded carbon layer by modifying halloysite nanotubes to ensure that the expanded carbon layer achieves the heat-insulating effect.
[0007] To achieve the above object, the present invention provides a thermally expandable heat-insulating and flame-retardant battery coating, which comprises 40-60 parts by mass of an organic expandable flame retardant, 20-40 parts by mass of a matrix resin, and 2-8 parts by mass of modified halloysite nanotubes, wherein the organic expandable flame retardant is composed of an acid source, a carbon source and a gas source.
[0008] Preferably, the acid source is an inorganic acid, ammonium polyphosphate, (NH 4 ) 2 SO 4 、NH 4 Cl, a mixture of one or more of amine / amide phosphates, wherein the inorganic acid includes H 3 PO 4 、H 2 SO 4 、H 3 BO 3 One of them.
[0009] Preferably, the gas source is a mixture of one or more of melamine, dicyandiamide, and dicyandiamide formaldehyde resin.
[0010] Preferably, the carbon source is a mixture of one or more of polyhydroxy compounds, melamine formaldehyde resin, and acetaldehyde resin, wherein the polyhydroxy compound includes one of starch, dextrin, sorbitol, and pentaerythritol.
[0011] Preferably, the matrix resin is a mixture of one or more of pure acrylic resin, silicone acrylic resin, vinyl acetate acrylic resin, and waterborne epoxy resin.
[0012] The preparation method of the above thermally expandable heat-insulating and flame-retardant battery coating comprises the following steps: S1. Prepare modified halloysite nanotubes; S2. After polishing the surface of the aluminum plate with sandpaper, rinse it with anhydrous ethanol and set aside; S3. Weigh the organic expandable flame retardant and the modified halloysite nanotubes into a beaker, and use mechanical high-speed stirring to fully mix the powders evenly to obtain a mixed powder; S4. Add the matrix resin to the mixed powder, stir for 20-40 min, then add water, continue mechanical stirring for 20-40 min, and prepare a coating on the aluminum plate of S2 through an automatic film coater.
[0013] Preferably, the preparation of the modified halloysite nanotubes in S1 comprises the following steps: S1.1. Mix ethanol and a precursor in a volume ratio of 10:40, then slowly add a pH regulator under stirring conditions, and continue stirring after adding to prepare a reaction solution; S1.2. Slowly drop the reaction solution obtained in S1.1 into deionized water. After the dropping is completed, continuously stir for 20 - 40 min to prepare a mixed solution; S1.3. Let the mixed solution stand and age at room temperature for 24 hours to form a sol - gel system; S1.4. Add the etched halloysite nanotubes into the sol - gel system in S1.3. After continuously reacting for 18 - 22 h, wash and dry to obtain modified halloysite nanotubes.
[0014] Preferably, the precursor in S1.1 is one or a mixture of tetraethyl orthosilicate, tetrabutyl titanate, titanium tetraisopropoxide, γ - aminopropyltriethoxysilane, γ - glycidoxypropyltrimethoxysilane.
[0015] Preferably, the pH regulator in S1.1 is concentrated hydrochloric acid or concentrated nitric acid, and the addition amount of the pH regulator is 5% - 15% of the volume of ethanol.
[0016] Preferably, the halloysite nanotubes in S1.4 are etched with a 1wt% hydrochloric acid solution.
[0017] Preferably, the amount of water in S4 is 0.5 - 2 times the mass of the matrix resin.
[0018] The application of the above - mentioned thermal expansion, heat insulation and flame - retardant battery coating is applied to new energy batteries.
[0019] Advantages of the present invention: (1) The present invention adopts the above - mentioned thermal expansion, heat insulation and flame - retardant battery coating. The used modified halloysite nanotubes have characteristics such as high thermal stability and easy dispersion, which can improve the thermal stability of the expanded carbon layer, can be evenly distributed in the coating, enhance the overall stability and consistency of the coating, avoid problems such as cracking and peeling during long - term use of the coating, and ensure that the coating can always play the role of heat insulation and flame retardancy.
[0020] (2) The present invention adopts the above - mentioned thermal expansion, heat insulation and flame - retardant battery coating, which can reduce the damage of high temperature to the internal electrode materials, electrolytes, etc. of the battery, maintain the stable electrochemical performance of the battery, can well solve the problem of thermal runaway of the battery pack, reduce the occurrence of safety accidents such as battery thermal runaway and combustion, and extend the service life and cycle times of the battery.
[0021] (3) The present invention adopts the preparation method of the above - mentioned thermal expansion, heat insulation and flame - retardant battery coating. The preparation method is simple, the technological process is concise, it can significantly shorten the production time of the coating, the production process is easy to adjust and control, which is conducive to the popularization and diffusion of the technology.
[0022] The technical solution of the present invention will be further described in detail below through the drawings and examples. Description of the drawings
[0023] Figure 1 It is the thermal expansion effect diagram of the coating prepared in Example 1 of the present invention; Figure 2 It is the thermal expansion effect diagram of the coating prepared in Example 2 of the present invention; Figure 3 It is the thermal expansion effect diagram of the coating prepared in the comparative example of the present invention; Figure 4 It is the back temperature curve diagram of the coatings obtained in Examples 1-2 and the comparative example of the present invention; Figure 5 It is the schematic diagram of the residual carbon combination of the coating obtained in Example 1 of the present invention after heat treatment. Detailed implementation manners
[0024] The present invention will be further described below in conjunction with the drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those of ordinary skill in the field to which the present invention belongs. The above-mentioned features mentioned in the present invention or the features mentioned in the specific examples can be combined arbitrarily. These specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.
[0025] Example 1 The present invention provides a preparation method of a thermal expansion heat insulation and flame retardant battery coating, including the following steps, S1. Prepare modified halloysite nanotubes S1.1. Mix ethanol and tetrabutyl titanate according to a volume ratio of 10:40, then slowly add 1 mL of concentrated nitric acid under stirring at 1000 rpm, and continue stirring for 5 min after adding to prepare a reaction solution; S1.2. Slowly add the reaction solution obtained in S1.1 to 100 mL of deionized water, and continue stirring for 30 min after the addition to prepare a mixed solution; S1.3. Let the mixed solution stand and age at room temperature for 24 hours to form a sol-gel system composed of tetrabutyl titanate, ethanol, concentrated nitric acid and water; S1.4. Etch 10 g of halloysite nanotubes (HNTs) with a 1 wt% hydrochloric acid solution, add the sol-gel system of S1.3 to a 200 mL beaker, then add the etched halloysite nanotubes, stir slowly for 1 hour, continue the reaction for 20 h, then centrifuge at 9000 rpm for 10 minutes, then wash once with ethanol and twice with distilled water. Finally, dry the sample at 100 °C for 5 hours to obtain modified halloysite nanotubes (Ti-HNTs).
[0026] S2. Place the aluminum plate (10×10×0.3 cm 3After the surface is polished with 400# sandpaper, it is rinsed with absolute ethanol and reserved.
[0027] S3. Weigh 28 g of ammonium polyphosphate (APP), 16 g of melamine (MEL), 16 g of pentaerythritol (PER), 2 g of boric acid and 4 g of Ti-HNTs into a beaker, and use mechanical high-speed stirring to make the powder fully mixed and uniform, obtaining a mixed powder.
[0028] S4. Add 34 g of waterborne epoxy resin to the mixed powder, stir for 30 min, then add 20 g of water, continue mechanical stirring for 30 min, and then prepare a coating on the aluminum plate of S2 through an automatic film coater.
[0029] Example 2 The present invention provides a preparation method of a thermally expandable heat-insulating and flame-retardant battery coating, including the following steps. S1. Prepare modified halloysite nanotubes S1.1. Mix ethanol and tetrabutyl titanate according to a volume ratio of 10:40, then slowly add 1 mL of concentrated nitric acid under stirring at 1000 rpm, and continue stirring for 5 min after adding to prepare a reaction solution. S1.2. Slowly drop the reaction solution obtained in S1.1 into 100 mL of deionized water, and continue stirring for 30 min after dropping to prepare a mixed solution. S1.3. Let the mixed solution stand and age at room temperature for 24 hours to form a sol-gel system composed of tetrabutyl titanate, ethanol, concentrated nitric acid and water. S1.4. Etch 10 g of HNTs with a 1 wt% hydrochloric acid solution, add the sol-gel system of S1.3 into a 200 mL beaker, then add the etched halloysite nanotubes, slowly stir for 1 hour, continue the reaction for 20 h, then centrifuge at 9000 rpm for 10 minutes, then wash once with ethanol and twice with distilled water. Finally, dry the sample at 100 °C for 5 hours to obtain Ti-HNTs.
[0030] S2. For the aluminum plate (10×10×0.3 cm 3 ), after the surface is polished with 400# sandpaper, it is rinsed with absolute ethanol and reserved.
[0031] S3. Weigh 28 g of APP, 16 g of MEL, 16 g of PER, 2 g of boric acid and 8 g of Ti-HNTs into a beaker, and use mechanical high-speed stirring to make the powder fully mixed and uniform, obtaining a mixed powder.
[0032] S4. Add 30 g of waterborne epoxy resin to the mixed powder, stir for 30 min, then add 20 g of water, continue mechanical stirring for 30 min, and then prepare a coating on the aluminum plate of S2 through an automatic film coater.
[0033] Comparative Example A method for preparing a battery coating includes the following steps: S1. After polishing the surface of an aluminum plate (10×10×0.3 cm 3 ) with 400# sandpaper, rinse it with absolute ethanol and set aside.
[0034] S2. Weigh 28 g of APP, 16 g of MEL, 16 g of PER and 2 g of boric acid in a beaker, and use mechanical high-speed stirring to fully mix the powder evenly to obtain a mixed powder.
[0035] S4. Add 38 g of waterborne epoxy resin to the mixed powder, stir for 30 min, then add 20 g of water, continue mechanical stirring for 30 min, and then prepare a coating on the aluminum plate in S2 through an automatic film coater.
[0036] Performance Test Heat-treat the coatings prepared in Examples 1-2 and the comparative example, and observe their swelling effects. As Figures 1 to 3 shown, when the comparative example does not add Ti-HNTs, the organic part of the coating in the comparative example has a good swelling effect, and the swelling multiple reaches 31.2 times. With the addition of Ti-HNTs, the swelling effect shows a trend of first increasing and then decreasing. The swelling multiples of Example 1 and Example 2 are 34.9 times and 22.0 times respectively. The swelling effect of Example 1 is better than that of the comparative example and Example 2, showing an excellent swelling effect.
[0037] Figure 4 This is the back temperature curve graph of the coatings obtained in Examples 1-2 and the comparative example of the present invention. As Figure 4 shown, after 10 min of fire resistance, the back temperature of the comparative example reaches 426.5 °C, showing poor heat insulation performance. In contrast, the back temperature of Example 1 is 202.1 °C, showing a significant improvement in heat insulation performance, which is significantly lower than the back temperature of the comparative example. Further increasing the proportion of Ti-HNTs to 8%, the back temperature of Example 2 rises to 321.5 °C, which is also lower than that of the comparative example, but a high proportion of Ti-HNTs may cause the coating structure to be too dense, affecting its swelling property and heat insulation effect, resulting in a slight decrease in heat insulation performance. Therefore, Example 1 shows better heat insulation performance.
[0038] Figure 5 This is a schematic diagram of the residual carbon combination of the coating obtained in Example 1 of the present invention after heat treatment. As Figure 5 shown in a) and b) in it, the outer surface of the carbon layer formed by the coating is uniform and dense, the structure of the outer surface of the carbon layer is relatively flat, the particles are small and arranged regularly, and there are almost no cracks and obvious pores on the surface, indicating that the coating has good heat insulation performance at high temperatures and effectively prevents the diffusion of flames and heat. ThroughFigure 5 In c) and d), the inner surface of the carbon layer was analyzed and it was found that the inner surface of the carbon layer presented an obvious honeycomb-like bubble structure with good expansion effect and relatively uniform structure. The honeycomb-like bubbles are typical structures formed by the expansion of the carbon layer under high-temperature conditions. This structure can effectively isolate heat propagation and reduce the heat transfer to the substrate. The relatively uniform distribution of the bubbles indicates that the coating has undergone a good expansion reaction at high temperature, forming a stable and dense heat insulation layer. This uniform honeycomb structure helps to improve the heat isolation ability and fire resistance of the coating.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements do not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A thermal expansion heat insulation flame retardant battery coating, characterized in that: The coating comprises 40-60 parts of an organic intumescent flame retardant, 20-40 parts of a matrix resin, and 2-8 parts of modified halloysite nanotubes by mass, wherein the organic intumescent flame retardant is composed of an acid source, a carbon source, and a gas source.
2. A thermal expansion heat insulation flame retardant battery coating according to claim 1, characterized in that: The acid source is one or a mixture of inorganic acid, ammonium polyphosphate, (NH4)2SO4, NH4Cl, amine / amide phosphate, wherein the inorganic acid includes one of H3PO4, H2SO4, and H3BO3.
3. The thermal expansion heat insulation flame retardant battery coating according to claim 1, characterized in that: The gas source is one or a mixture of melamine, dicyandiamide, dicyandiamide formaldehyde resin.
4. The thermal expansion heat insulation flame retardant battery coating according to claim 1, characterized in that: The carbon source is one or a mixture of polyhydroxy compounds, melamine formaldehyde resin, acetaldehyde resin, wherein the polyhydroxy compounds include one of starch, dextrin, sorbitol and pentaerythritol.
5. The thermal expansion heat insulation flame retardant battery coating according to claim 1, characterized in that: The matrix resin is one or a mixture of pure acrylic resin, silicone acrylic resin, vinyl acetate acrylic resin, and water-based epoxy resin.
6. A method for preparing a thermal expansion heat insulation flame retardant battery coating according to any one of claims 1 to 5, characterized in that: The following steps are included: S1. preparing modified halloysite nanotubes; S2. Polish the surface of the aluminum plate with sandpaper, rinse it with anhydrous ethanol and set aside; S3, weighing the organic intumescent flame retardant and the modified halloysite nanotubes in a beaker, and using mechanical high-speed stirring to fully mix the powders to obtain a mixed powder; S4. Add base resin to the mixed powder, stir for 20 to 40 minutes, add water, continue mechanical stirring for 20 to 40 minutes, and then prepare a coating on the aluminum plate of S2 by an automatic coating machine.
7. The method for preparing a thermal expansion heat insulation flame retardant battery coating according to claim 6, characterized in that: The preparation of modified halloysite nanotubes in S1 comprises the following steps: S1.1, ethanol and the precursor are mixed in a volume ratio of 10:40, and then a pH regulator is slowly added under stirring, and stirring is continued after the addition to prepare a reaction solution; S1.2, slowly add the reaction solution obtained in S1.1 dropwise into deionized water, and after the addition is complete, continue stirring for 20 to 40 minutes to prepare a mixed solution; S1.3, leaving the mixed solution to stand at room temperature for 24 hours to form a sol-gel system; S1.4, adding the etched halloysite nanotubes into the sol-gel system of S1.3, continuing the reaction for 18 to 22 hours, washing and drying to obtain modified halloysite nanotubes.
8. The method for preparing a thermal expansion heat insulation flame retardant battery coating according to claim 7, characterized in that: The precursor in S1.1 is one or a mixture of tetraethyl orthosilicate, tetrabutyl titanate, titanium tetraisopropoxide, γ-aminopropyltriethoxysilane, and γ-glycidyloxypropyltrimethoxysilane.
9. The method for preparing a thermal expansion heat insulation flame retardant battery coating according to claim 7, characterized in that: The amount of water in S4 is 0.5~2 times the mass of the base resin.
10. An application of the thermal expansion heat insulation flame retardant battery coating according to any one of claims 1 to 5, characterized in that: Used in new energy batteries.