An aerogel-containing thermal insulation film and a preparation method and application thereof

Abstract

The application belongs to the technical field of thermal insulation films, and relates to a gas gel-containing thermal insulation film and a preparation method and application thereof. The gas gel-containing thermal insulation film comprises, from top to bottom, a heat-sealing layer, a thermal insulation layer, a bonding layer, a metal barrier layer and an insulation layer which are stacked in sequence; the thickness of the thermal insulation layer is 50-300 mu m, and the material is a gas gel material; and the thermal conductivity coefficient of the gas gel material is 0.02-0.03 W / (m*K). The thermal conductivity coefficient of the gas gel-containing thermal insulation film is lower than 0.04 W / (m*K), and the thermal insulation film has excellent mechanical strength and thermal insulation performance, and the tensile strength is not lower than 100 MPa.

Description

Technical Field

[0001] This invention belongs to the field of heat insulation film technology, and relates to a heat insulation film containing aerogel, its preparation method and application. Background Technology

[0002] Thermal insulation film is a type of multi-layered flexible composite material made from a metal layer and a polymer plastic film through a composite process. Due to its gas barrier properties, this material effectively prevents external oxygen and moisture from entering the battery, thereby inhibiting electrolyte decomposition and providing crucial protection for extending battery cycle life and storage stability. Its excellent flexibility allows it to adapt to the volume expansion and contraction during battery charging and discharging, reducing the shedding of active electrode materials, while also accommodating irregularly shaped battery designs, improving the space utilization of battery packs.

[0003] In the application of encapsulating phase change materials, commonly used heat-insulating films such as polymer composite films and flexible shaped composite films often have insufficient interlayer bonding force when used to encapsulate phase change materials, leading to peeling or blistering, which affects the encapsulation integrity of the phase change materials and limits their wider application in this field. Summary of the Invention

[0004] This invention provides a heat insulation film containing aerogel, its preparation method, and its application, in order to solve the problem of weak interlayer bonding strength in related technologies.

[0005] To solve the above-mentioned technical problems, in a first aspect, the present invention provides a heat insulation film containing aerogel, wherein the heat insulation film containing aerogel comprises, from top to bottom, a heat sealing layer, a heat insulation layer, an adhesive layer, a metal barrier layer and an insulating layer. The thickness of the insulation layer is 50~300 µm, and the material is aerogel, with a thermal conductivity of 0.02~0.03 W / (m·K).

[0006] In some specific embodiments of the present invention, the total thickness of the heat insulation film is 120~520 µm; and / or, The thickness of the heat-sealing layer is 30~100 µm; and / or, The thickness of the adhesive layer is 2~5 µm; and / or, The thickness of the metal barrier layer is 20~60 µm; and / or, The thickness of the insulating layer is 20~50 µm.

[0007] In some specific embodiments of the present invention, the metal barrier layer is an aluminum foil layer; and / or, The thermal conductivity of the aerogel-containing insulation film is less than 0.04 W / (m·K).

[0008] Secondly, the present invention provides a method for preparing a heat insulation film containing aerogel, comprising the following steps: An insulating layer is laminated onto one side of the metal barrier layer. The other side surface of the metal barrier layer is pretreated, and then a first adhesive is applied to the surface and dried for the first time to form an adhesive layer. An aerogel slurry is coated onto the adhesive layer and dried a second time to form a heat insulation layer with an integrated composite structure with the adhesive layer. A second adhesive is applied to the heat insulation layer, and a third drying is performed to form a heat-sealing layer, thus obtaining a heat insulation film containing aerogel.

[0009] In some specific embodiments of the present invention, the aerogel slurry comprises, by weight, 5-20 parts of aerogel particles, 10-40 parts of glass microspheres, 1-5 parts of ceramic fibers, 10-20 parts of film-forming agent, 0.5-2 parts of thickener, and 40-70 parts of solvent.

[0010] In some specific embodiments of the present invention, the aerogel particles are one or more of silica aerogel, alumina aerogel, and carbon aerogel, with a particle size distribution of 1~100 μm and a thermal conductivity at room temperature of 0.012~0.025 W / (m·K); and / or, The glass microspheres are hollow glass microspheres, and the specific gravity of the hollow glass microspheres is 0.1~0.5 g / cm³. 3 The particle size distribution is 5–100 µm; and / or, The ceramic fiber is one or more of aluminosilicate ceramic fiber and alumina fiber; and / or... The film-forming agent is one or more selected from epoxy resin, silicone resin, and acrylic resin; and / or, The thickener is one or more of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium carboxymethyl cellulose.

[0011] In some specific embodiments of the present invention, the specific preparation method of the adhesive layer includes: performing an alkaline washing and activation treatment on the other side surface of the metal barrier layer, then coating the surface with a first adhesive, and drying the first time at 80~100°C for 2~5 minutes to form an adhesive layer.

[0012] In some specific embodiments of the present invention, the specific preparation method of the heat insulation layer includes: adding aerogel particles, glass microspheres, ceramic fibers, film-forming agents and thickeners to a solvent to prepare an aerogel slurry; vacuum degassing the aerogel slurry; and coating the degassed aerogel slurry onto the adhesive layer by a casting process. The casting process parameters include: a doctor blade height of 120~140 µm and a casting speed of 0.5~0.8 m / min; and a second drying condition of 90~110℃ for 2~5 minutes to form the heat insulation layer.

[0013] In some specific embodiments of the present invention, the specific preparation method of the heat-sealing layer includes: coating a second adhesive onto the heat insulation layer using a casting process, wherein the casting process parameters include: a scraper height of 120~140 µm and a casting speed of 0.5~0.8 m / min; and a third drying condition of 90~100℃ for 2~6 minutes to form a heat-sealing layer.

[0014] Thirdly, the present invention provides an application of an aerogel-containing heat-insulating film in encapsulating phase change materials.

[0015] The beneficial effects of the present invention include at least the following: The aerogel-containing heat insulation film of the present invention comprises, from top to bottom, a heat-sealing layer, a heat insulation layer, an adhesive layer, a metal barrier layer and an insulating layer, and the thermal conductivity of the heat insulation film is less than 0.04 W / (m·K).

[0016] This invention relates to an aerogel-containing thermal insulation film that, through synergistic optimization of interlayer structure and process parameters, achieves both excellent mechanical strength and thermal insulation performance, with a tensile strength of not less than 100 MPa. This thermal insulation film is particularly suitable for encapsulation applications requiring efficient thermal management, such as those involving phase change materials. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of the heat insulation film of Embodiment 1 of the present invention; wherein, 1, heat sealing layer; 2, heat insulation layer; 3, adhesive layer; 4, aluminum foil layer; 5, insulation layer.

[0019] Figure 2 The diagram (a) shows the thermal insulation film encapsulating the phase change material in Embodiment 1 of the present invention, and the schematic diagram (b) shows its application scenario between battery cells. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions 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, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] In a first aspect, the present invention provides a heat insulation film containing aerogel, wherein the heat insulation film comprises, from top to bottom, a heat sealing layer, a heat insulation layer, an adhesive layer, a metal barrier layer and an insulating layer stacked together; The thickness of the insulation layer is 50~300 µm, and the material is aerogel. The thermal conductivity of the aerogel is 0.02~0.03 W / (m·K), in order to solve the problem of rapid thermal conductivity of insulation films in related technologies.

[0022] This invention first solidifies a stable and easily bonded substrate using an adhesive layer; then, an aerogel slurry is applied to this substrate, utilizing the slurry's fluidity to penetrate the cross-section of the adhesive layer; finally, it is cured to form a thermal insulation layer with an integrated composite structure. This composite thermal insulation layer combines the excellent sealing and barrier properties of aluminum-plastic film against water and air with the highly efficient thermal insulation characteristics of aerogel. This material is not prone to powdering or delamination, has good mechanical properties, and its thermal insulation function is primarily achieved by the aerogel layer. Its overall performance is significantly superior to traditional aluminum-plastic film encapsulation materials.

[0023] In some specific embodiments of the present invention, the total thickness of the heat insulation film is 120~520 µm; and / or, The thickness of the heat-sealing layer is 30~100 µm; and / or, The thickness of the adhesive layer is 2~5 µm; and / or, The thickness of the metal barrier layer is 20~60 µm; and / or, The thickness of the insulating layer is 20~50 µm.

[0024] In some specific embodiments of the present invention, the metal barrier layer is an aluminum foil layer; and / or, The out-of-plane thermal conductivity of the heat insulation film is less than 0.04 W / (m·K).

[0025] Among metal barrier layer materials, aluminum foil has a greater overall advantage over stainless steel foil, copper foil, etc., due to its excellent gas-liquid barrier properties, unique flexibility, and moderate strength.

[0026] Secondly, the present invention provides a method for preparing a heat-insulating film, comprising the following steps: S1. A 100% solid content two-component polyurethane adhesive (polyurethane to curing agent mass ratio of 4:1) is applied to the metal aluminum foil by a pressure roller. Then, it is hot-pressed to another insulating layer, nylon (PA) material, by a pressure roller. The adhesive is cross-linked and cured by curing at 50°C to form a high-strength aluminum foil / PA composite layer. S2. The other side of the aluminum foil is subjected to alkaline washing and activation treatment, and then the first adhesive is coated on the surface using a casting process to form a first wet film. The casting process parameters include: squeegee height of 120~140 µm, casting speed of 0.5~0.8 m / min; and first drying conditions of 80~100℃ for 2~5 minutes to form an adhesive layer. S3. Aerogel particles, glass microspheres, ceramic fibers, film-forming agents, and thickeners are added to a solvent to prepare an aerogel slurry. The aerogel slurry is then degassed under vacuum. The degassed aerogel slurry is then coated onto the adhesive layer using a casting process to form a second wet film. The casting process parameters include: a doctor blade height of 120~140 µm and a casting speed of 0.5~0.8 m / min. The second drying conditions are 90~110℃ for 2~5 minutes to form a heat insulation layer. S4. A second adhesive is coated onto the heat insulation layer using a casting process to form a third wet film. The casting process parameters include: a doctor blade height of 120~140 µm and a casting speed of 0.5~0.8 m / min. The third drying conditions are 90~100℃ for 2~6 minutes to form a heat-sealing layer, thereby obtaining a heat insulation film containing aerogel.

[0027] By adjusting the doctor blade height and casting speed, the thickness of the first, second, and third wet films can be precisely controlled. After drying and curing, the average thickness of the resulting adhesive layer, insulation layer, and heat-sealing layer is approximately 76±2% of the corresponding wet film thickness. This process provides uniform coating, dense interlayer bonding, and is simple, repeatable, and suitable for large-scale production. Furthermore, the wet casting process ensures the slurry spreads evenly in a liquid state, facilitating thorough wetting and good bonding between layers.

[0028] In some specific embodiments of the present invention, a 100% solids content adhesive is coated onto a pressure roller on an aluminum foil. The adhesive is a two-component solvent-free polyurethane adhesive, wherein the mass ratio of polyurethane to curing agent is 4:1. The polyurethane containing hydroxyl functional groups is an acrylic resin, polyester resin, or polyether resin. The isocyanate compound in the curing agent that can react with the hydroxyl functional groups is an HDI trimer, a TDI adduct, or a hydrophilic modified isocyanate.

[0029] In some specific embodiments of the present invention, the aerogel slurry comprises: 5-20 parts by weight of aerogel particles, 10-40 parts by weight of glass microspheres, 1-5 parts by weight of ceramic fibers, 10-20 parts by weight of film-forming agent, 0.5-2 parts by weight of thickener, and 40-70 parts by weight of solvent.

[0030] In some specific embodiments of the present invention, the aerogel particles are selected from one or more of silica aerogel, alumina aerogel, and carbon aerogel, with a particle size distribution of 1~100μm and a thermal conductivity of 0.012~0.025 W / (m·K) at room temperature. These raw materials have good insulation, corrosion resistance, flame retardancy, and thermal insulation properties, and can be attached to the surface of modified metal, plastic, and other substrates using a casting process. They are suitable for mass production of thermally insulating encapsulation materials, adapting to the thermal insulation needs of various scenarios such as new energy battery packs, and combining energy saving with long-term stability.

[0031] In some specific embodiments of the present invention, the glass microspheres are hollow glass microspheres, and the specific gravity of the hollow glass microspheres is 0.1~0.5 g / cm³. 3 The particle size distribution is 5~100 µm.

[0032] In some specific embodiments of the present invention, the ceramic fiber is one or more of aluminosilicate ceramic fiber and alumina fiber, and the fiber length is 10~500μm.

[0033] In some specific embodiments of the present invention, the film-forming agent is one or more of epoxy resin, silicone resin, and acrylic resin. Specifically, the epoxy resin includes glycidyl ethers, glycidyl esters, glycidyl amines, linear aliphatic epoxy resins, and alicyclic epoxy resins. The silicone resin includes methyl silicone resin, vinyl methyl silicone resin, methyl phenyl silicone resin, or epoxy-modified silicone resin. The acrylic resin includes polymethyl methacrylate, acrylic emulsion resin, acrylic ester resin, and acrylic copolymer.

[0034] In some specific embodiments of the present invention, the thickener is one or more of hydroxyethyl cellulose, hydroxypropyl methylcellulose, and sodium carboxymethyl cellulose. Both hydroxyethyl cellulose and hydroxypropyl methylcellulose are nonionic, exhibiting good resistance to acids, alkalis, and electrolytes, and are highly versatile. The viscosity range of hydroxyethyl cellulose can be selected as 3,000–15,000 mPa·s, and the viscosity range of hydroxypropyl methylcellulose as 4,000–15,000 mPa·s. Sodium carboxymethyl cellulose is anionic, providing good thickening and film-forming effects; a viscosity range of 800–3,000 mPa·s can be selected.

[0035] In some specific embodiments of the present invention, water is used as the solvent when preparing the aerogel slurry. The preparation of the aerogel slurry uses water as the main solvent, and by adding film-forming agents and thickeners, hydrophobic aerogel powder is uniformly dispersed in water to form a stable suspension system. Compared to systems using organic solvents, the aerogel slurry of the present invention is safer and more environmentally friendly, and can form a uniform heat-insulating layer through a casting process.

[0036] In some specific embodiments of the present invention, the first adhesive is one or more of waterborne acrylic resin, two-component polyurethane, waterborne polyurethane, bisphenol A type epoxy resin or bisphenol F type epoxy resin.

[0037] Specifically, waterborne acrylic resins include all-acrylic waterborne resins, styrene-acrylic waterborne resins, silicone-acrylic waterborne resins, vinyl-acrylic waterborne resins, fluoroacrylic waterborne resins, and tert-acrylic waterborne resins. Two-component polyurethanes, classified by hydroxyl component type, include polyester type, polyether type, acrylic type, alkyd type, and epoxy type; classified by isocyanate type, they include aliphatic isocyanates and aromatic isocyanates. Bisphenol A type epoxy resins include liquid bisphenol A type epoxy resins, solid bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, waterborne bisphenol A type epoxy resins, solvent-based bisphenol A type epoxy resins, and high-purity electronic-grade bisphenol A type epoxy resins. Bisphenol F type epoxy resins include liquid bisphenol F type epoxy resins, solid bisphenol F type epoxy resins, low-viscosity bisphenol F type epoxy resins, medium-viscosity bisphenol F type epoxy resins, and high-viscosity bisphenol F type epoxy resins.

[0038] Specifically, the second adhesive is an acid-modified polypropylene solution, the solute is acid-modified polypropylene particles, and the solvent is a mixture of xylene and ethyl acetate in a volume ratio of 7:3.

[0039] The technical solution provided by the present invention will be described in detail below with reference to the embodiments.

[0040] The raw materials involved in this invention embodiment are sourced from: acrylic resin purchased from BASF Europe, and two-component solvent-free polyurethane adhesive, silica aerogel, hollow glass microspheres, aluminum silicate ceramic fiber, polymethyl methacrylate, hydroxyethyl cellulose, acid-modified polypropylene particles, alumina aerogel, and alumina fiber all purchased from Shanghai Kangda New Materials Co., Ltd.

[0041] Diluting method for 30% solids acrylic resin: Place 700 g of weighed cyclohexane in a reaction vessel equipped with stirring and heating, and heat to 50°C and maintain the temperature. While stirring at 200 rpm, continuously, slowly, and in batches add 300 g of solid acrylic resin to the cyclohexane to prevent clumping. After the addition is complete, continue stirring at 50°C and 200 rpm for 6 hours until the resin is completely dissolved and the system is homogeneous and transparent. Cool the transparent solution to 25°C. Then, perform vacuum degassing at -0.09 MPa. Finally, filter the solution using a 400-mesh filter bag to remove any trace amounts of insoluble matter or impurities, obtaining an acrylic resin solution with a solids content of 30%.

[0042] Acid-modified polypropylene solution with a solid content of 30% was prepared as follows: 560 mL of xylene and 240 mL of ethyl acetate were mixed thoroughly in a reaction vessel. The mixed solvent was heated to 60°C. Under continuous magnetic stirring at 400 rpm, 300 g of pre-mixed acid-modified polypropylene granules and 1 g of antioxidant 1010 were slowly added to the solvent. After the addition was complete, the mixture was stirred continuously at a constant temperature of 60°C for 3 hours until the solid granules were completely dissolved, forming a homogeneous, transparent, viscous solution. The solution was then degassed under a vacuum of -0.09 MPa and cooled to room temperature to obtain an acid-modified polypropylene solution with a solid content of 30%.

[0043] Example 1: The method for preparing a heat-insulating film includes the following steps: S1. A 100% solid content two-component solvent-free polyurethane adhesive is applied to a 40 µm aluminum foil by a pressure roller, wherein the mass ratio of hydroxyl acrylic resin to HDI trimer is 4:1. The adhesive is then hot-pressed onto another insulating layer, nylon (PA) material, by a pressure roller and cured at 50°C to achieve cross-linking and curing of the adhesive, forming an insulating layer with a thickness of 30 µm on one side of the aluminum foil layer. S2. Clean the other side of the 40 µm aluminum foil with 2% sodium hydroxide solution, treat at 50°C for 5 minutes, immerse in 25% nitric acid solution at room temperature for 3 minutes, then ultrasonically clean twice, 3 minutes each time. Next, coat the aluminum foil surface with 30% acrylic resin using a casting process to form a first wet film, controlling the squeegee height to be 10 µm and the casting speed to be 0.7 m / min; dry at 90°C for 4 minutes, and obtain an adhesive layer with a thickness of 3 µm after drying. S3, 12 parts of silica aerogel with a particle size of 85µm and a room temperature thermal conductivity of 0.019 W / (m·K), and 25 parts of silica aerogel with a specific gravity of 0.3 g / cm³. 3 Aerogel slurry was prepared by dissolving 75 µm hollow glass microspheres, 3 parts aluminosilicate ceramic fibers with a fiber length of 400 µm, 15 parts polymethyl methacrylate, and 1 part hydroxyethyl cellulose in 40 parts water. The aerogel slurry was then degassed under vacuum at room temperature and a vacuum degree of -0.1 MPa until the bubbles were almost completely eliminated. The degassed aerogel slurry was then coated onto the adhesive layer to form a second wet film using a casting process with a doctor blade height of 130 µm and a casting speed of 0.7 m / min. The second drying conditions were 100 °C for 5 minutes to form a 100 µm thick heat insulation layer. S4. A third wet film is formed by coating the insulation layer with a 30% acid-modified polypropylene solution using a casting process. The doctor blade height is 100 µm and the casting speed is 0.6 m / min. The third drying conditions are 100℃ for 5 minutes, forming a thickness of 80 µm, resulting in a 253 µm thick insulation film containing aerogel. The insulation film structure is shown below. Figure 1 .

[0044] Example 2 The preparation method of the heat insulation film in Example 2 is the same as that in Example 1, except that the amount of silica aerogel in the aerogel slurry is different, which is 5 parts (see Table 1).

[0045] Example 3 The preparation method of the heat insulation film in Example 3 is the same as that in Example 1, except that the amount of silica aerogel in the aerogel slurry is different, which is 20 parts (see Table 1).

[0046] Example 4 The preparation method of the heat insulation film in Example 4 is the same as that in Example 1, except that the aerogel particles in the aerogel slurry are alumina aerogel with a particle size of 90µm and a thermal conductivity of 0.021W / (m·K) at room temperature (see Table 1).

[0047] Example 5 The preparation method of the heat insulation film in Example 5 is the same as that in Example 1, except that the ceramic fiber in the aerogel slurry is alumina fiber with a fiber length of 400 μm (see Table 1).

[0048] Example 6 The preparation method of the heat insulation film in Example 5 is the same as that in Example 1, except that the thickness of the heat insulation layer obtained is 280 µm (see Table 1).

[0049] Comparative Example 1 The preparation method of the heat insulation film in Comparative Example 1 is the same as that in Example 1, except that the amount of silica aerogel in the aerogel slurry is different, which is 3 parts (see Table 1).

[0050] Comparative Example 2 The preparation method of the heat insulation film in Comparative Example 2 is the same as that in Example 1, except that the amount of silica aerogel in the aerogel slurry is different, which is 35 parts (see Table 1).

[0051] Comparative Example 3 The preparation method of the heat insulation film in Comparative Example 3 is the same as that in Example 1, except that the heat insulation layer is prepared by a spraying process (see Table 1).

[0052] Comparative Example 4 The preparation method of the heat insulation film in Comparative Example 4 is the same as that in Example 1, except that it does not contain an adhesive layer (see Table 1).

[0053] Comparative Example 5 The preparation method of the heat insulation film in Comparative Example 5 is the same as that in Example 1, except that the thickness of the heat insulation layer is 400 µm (see Table 1).

[0054] Comparative Example 6 The preparation method of the heat insulation film in Comparative Example 6 is the same as that in Example 1, except that the thickness of the heat insulation layer is 40 µm (see Table 1).

[0055] Comparative Example 7 The preparation method of the heat insulation film of Comparative Example 7 is the same as that of Example 1, except that the thickness of the adhesive layer is 10 µm (see Table 1).

[0056] Interlayer bond strength tests were conducted on the heat insulation films of Examples 1-6 and Comparative Examples 1-7. The test process included: (1) Tensile strength test: Refer to the test method of tensile test in GB / T 38841-2020 5.6. Cut the aluminum-plastic film into dumbbell-shaped strips with a cutter. Use a universal testing machine to clamp the two ends of the sample and stretch it at a uniform speed of 300 mm / min until the sample breaks. On average, each group of samples is tested 3 times. Record the maximum tensile force at the time of breakage and calculate the tensile strength of the sample (maximum breaking tensile force / cross-sectional area of ​​sample fracture) and calculate the average value (the test results are shown in Table 2).

[0057] (2) Peel strength test: The two layers of aluminum-plastic film are peeled apart by a section and clamped on the upper and lower clamps of the tensile testing machine. The film is stretched at a constant speed of 300 mm / min to peel the two layers along the bonding interface. The peel force during the peeling process is recorded. The average peel force per unit width is calculated as the peel strength. Each group of samples is tested three times and the average value is calculated (the test results are shown in Table 2).

[0058] Thermal conductivity tests were conducted on the heat insulation films of Examples 1-6 and Comparative Examples 1-7, and the thermal conductivity coefficient of the heat insulation films was tested according to the method specified in GB / T 10294-2008.

[0059] The testing process includes: cutting size of 100 100 A 0.2mm heat insulation film was used as the test sample. The temperature difference between the upper and lower surfaces of the sample was tested using the steady-state heat flow method. The heat source temperature was a 200℃ programmable high-temperature heating plate (temperature control accuracy ±1℃). Thermocouples were attached to the symmetrical center positions of the upper and lower surfaces of the sample. To ensure a tight fit at the interface, a metal plate was placed on the upper surface of the sample (applying a contact pressure of 0.1MPa). The temperature of the upper and lower surfaces was recorded by the thermocouple collector, and the heat insulation temperature difference of the sample was calculated. The average thermal conductivity of the material was then calculated (test results are shown in Table 2).

[0060] Thermal conductivity tests were conducted on the phase change materials encapsulated with the heat-insulating films of Examples 1-6 and Comparative Examples 1-7. The test process included: See Figure 2a. The thermal conductivity of the phase change material encapsulated in the thermal insulation film was measured using the steady-state method: the sample consisted of a sandwich structure of thermal insulation film (100µm) / phase change film (200µm) / thermal insulation film (100µm), with the edges sealed by hot pressing (120℃, 0.15MPa pressure for 30 seconds). The sample size was 100µm. 100 0.4mm. Before the test, clean the surface of the hot and cold plates, apply a layer of thermal grease evenly, place the sample between the hot and cold plates, and apply a constant pressure of 0.15MPa. After the temperature stabilizes, record the heat flux density flowing through the sample and the measured temperature difference, and calculate the overall thermal conductivity of the entire sample (the test results are shown in Table 3).

[0061] In some specific embodiments of the present invention, according to Figure 2 As shown in diagram a, after the phase change material is encapsulated in a heat-insulating film, it can be placed between battery cells for thermal management. A schematic diagram of its application scenario is shown below. Figure 2 b.

[0062] Fatigue resistance tests were conducted on the heat insulation films used to encapsulate phase change materials in Examples 1-6 and Comparative Examples 1-7. The dynamic compression fatigue method was adopted, referring to the basic principles of the national standard GB / T 1687.3-2016 "Determination of temperature rise and fatigue resistance of vulcanized rubber in flexural test - Part 3: Compression flexural test" and the provisions of GB / T 2918-2018 "Standard environment for conditioning and testing of plastic specimens".

[0063] The testing process included: the sample was a sandwich structure of heat insulation film (100µm) / phase change film (200µm) / heat insulation film (100µm), with the edges sealed by heat pressing (120℃, 0.15MPa pressure for 30 seconds), and the sample size was 200. 150 0.4mm. During testing, the sample is mounted in the center of the fixture of the dynamic fatigue testing machine, a preload of 5N is applied, and the initial thickness d1 is recorded. The operating parameters simulating battery charge-discharge cycles are set as follows: minimum load 5N, maximum load 50N, cycle frequency 1Hz, total number of cycles 10000, ambient temperature 25℃, and relative humidity 50%. After starting the testing machine, the equipment will periodically apply compression-rebound loads until 10000 cycles are completed and then the machine is stopped. The sample thickness dn is measured, and the surface is observed for cracking, delamination, or particle shedding. The material attenuation rate on the thickness is calculated (thickness attenuation rate η = (d1 / dn)). dn) / d1×100%).

[0064] When the heat insulation film of Examples 1-6 and Comparative Examples 1-7 was used to encapsulate the phase change material, the encapsulation strength test was carried out in accordance with the national standard GB / T 1041-2008 "Determination of compressive properties of plastics".

[0065] The testing process includes: cutting size of 100 100 Three samples with a diameter of 0.4 mm were used. The testing environment was 25℃ and 50% relative humidity. The parallel stainless steel plates of the universal testing machine were adjusted to be completely parallel and the load was zeroed. The sample was placed in the center of the plates, and the compression rate was set to 0.2 mm / min. The testing machine was started to apply static pressure, and the load-displacement curve was recorded in real time until the sample showed obvious fracture. The maximum compressive force Fmax was recorded, and the compressive strength of the material was calculated according to Fmax / A0 (sample area).

[0066] Table 1. Parameters for preparing the heat insulation films of Examples 1-6 and Comparative Examples 1-7

[0067] Table 2. Performance test data of heat insulation films in Examples 1-6 and Comparative Examples 1-7

[0068] Table 3. Performance test data of phase change materials encapsulated with heat insulation film in Examples 1-6 and Comparative Examples 1-7

[0069] Table 2 shows that the data from Examples 1 and Comparative Examples 1, 2, 5, and 6 indicate that the aerogel particle content and the thickness of the insulation layer need to be within a suitable range to ensure that the insulation film has both high tensile strength (up to 130 MPa) and good thermal insulation performance (thermal conductivity <0.035 W / (m·K)). The data from Examples 1 and Comparative Example 3 show that the insulation film produced by the spraying process suffers from unevenness and unsatisfactory adhesion and wetting effects, and is not as stable and reliable as the insulation film produced by the casting process. The mechanical properties, interfacial adhesion strength, and thermal insulation performance of the insulation film in Comparative Example 3 are relatively poor. Examples 1 and Comparative Example 4 show that, without an adhesive layer, the interfacial adhesion strength of the insulation layer is very low, easily leading to breakage or delamination. Examples 1 and Comparative Example 7 show that increasing the thickness of the adhesive layer does not significantly improve the interfacial adhesion strength; instead, it reduces the thermal insulation performance of the film and increases material costs.

[0070] Table 3, comparing the examples and comparative examples, shows that the higher the overall mechanical strength (tensile strength and interfacial adhesive strength) of the phase change material encapsulated in the heat insulation film, the smaller the fatigue compressive deformation of the heat insulation film, the better the stability of the product dimensions, and the higher the compressive strength. Under similar mechanical performance conditions, the heat insulation performance (low thermal conductivity) of the phase change material encapsulated in the heat insulation film is mainly determined by the thickness of the aerogel insulation layer. The heat insulation aluminum-plastic film without an adhesive layer (Comparative Example 4) has poor compressive strength and shows signs of breakage during fatigue testing.

[0071] The results above demonstrate that by maintaining a reasonable coating formulation ratio, casting process, and material thickness, it is possible to prepare a heat-insulating film with strong mechanical properties, reliable interfacial adhesion, and high thermal insulation performance.

[0072] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0073] It should be noted that in this invention, relational terms such as "first" and "second" are used merely 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0074] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A heat insulation film containing aerogel, characterized in that, The aerogel-containing heat insulation film comprises, from top to bottom, a heat-sealing layer, a heat insulation layer, an adhesive layer, a metal barrier layer, and an insulating layer. The thickness of the insulation layer is 50~300 µm, and the material is aerogel, with a thermal conductivity of 0.02~0.03 W / (m·K).

2. The heat insulation film containing aerogel according to claim 1, characterized in that, The total thickness of the heat insulation film is 120~520 µm; and / or, The thickness of the heat-sealing layer is 30~100 µm; And / or, The thickness of the adhesive layer is 2~5 µm; And / or, The thickness of the metal barrier layer is 20~60 µm; and / or, The thickness of the insulating layer is 20~50 µm.

3. The heat insulation film containing aerogel according to claim 1, characterized in that: The metal barrier layer is an aluminum foil layer; and / or, The thermal conductivity of the aerogel-containing insulation film is less than 0.04 W / (m·K).

4. A method for preparing a heat insulation film containing aerogel, characterized in that, Includes the following steps: An insulating layer is laminated onto one side of the metal barrier layer. The other side surface of the metal barrier layer is pretreated, and then a first adhesive is applied to the surface and dried for the first time to form an adhesive layer. An aerogel slurry is coated onto the adhesive layer and dried a second time to form a heat insulation layer with an integrated composite structure with the adhesive layer. A second adhesive is applied to the heat insulation layer, and then dried a third time to form a heat-sealing layer, thus obtaining a heat insulation film containing aerogel.

5. The method for preparing the aerogel-containing heat insulation film according to claim 4, characterized in that, The aerogel slurry comprises, by weight, 5-20 parts aerogel particles, 10-40 parts glass microspheres, 1-5 parts ceramic fibers, 10-20 parts film-forming agent, 0.5-2 parts thickener, and 40-70 parts solvent.

6. The method for preparing the aerogel-containing heat insulation film according to claim 4, characterized in that, The aerogel particles are one or more of silica aerogel, alumina aerogel, and carbon aerogel, with a particle size distribution of 1~100μm and a thermal conductivity of 0.012~0.025 W / (m·K) at room temperature; and / or, The glass microspheres are hollow glass microspheres, and the specific gravity of the hollow glass microspheres is 0.1~0.5 g / cm³. 3 The particle size distribution is 5–100 µm; and / or, The ceramic fiber is one or more of aluminosilicate ceramic fiber and alumina fiber; and / or... The film-forming agent is one or more selected from epoxy resin, silicone resin, and acrylic resin; and / or, The thickener is one or more of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and sodium carboxymethyl cellulose.

7. The method for preparing the aerogel-containing heat insulation film according to claim 4, characterized in that, The specific preparation method of the adhesive layer includes: performing alkaline washing and activation treatment on the other side surface of the metal barrier layer, then coating the surface with a first adhesive, and drying the first time at 80~100℃ for 2~5 minutes to form an adhesive layer.

8. The method for preparing the aerogel-containing heat insulation film according to claim 4, characterized in that, The specific preparation method of the heat insulation layer includes: adding aerogel particles, glass microspheres, ceramic fibers, film-forming agents and thickeners to a solvent to prepare an aerogel slurry; vacuum degassing the aerogel slurry; and coating the degassed aerogel slurry onto the adhesive layer through a casting process. The casting process parameters include: a doctor blade height of 120~140 µm and a casting speed of 0.5~0.8 m / min; and a second drying condition of 90~110℃ for 2~5 minutes to form the heat insulation layer.

9. The method for preparing the aerogel-containing heat insulation film according to claim 4, characterized in that, The specific preparation method of the heat-sealing layer includes: coating the heat insulation layer with a second adhesive using a casting process, wherein the casting process parameters include: a scraper height of 120~140 µm and a casting speed of 0.5~0.8 m / min; and a third drying condition of 90~100℃ for 2~6 minutes to form the heat-sealing layer.

10. The use of the aerogel-containing heat-insulating film according to any one of claims 1 to 3 in encapsulating phase change materials.

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