Phase-change film material for thermal management of high-capacity energy storage battery as well as preparation method and application of phase-change film material

Abstract

The invention provides a phase change membrane material for thermal management of a high-capacity energy storage battery as well as a preparation method and application of the phase change membrane material, and belongs to the technical field of functional polymer materials. The phase-change film material is of a three-layer structure, the upper layer is an aerogel layer containing nanorod-shaped aluminum borate loaded melamine borate, the middle layer is a phase-change material layer containing gallium-indium alloy, and the lower layer is a heat-conducting insulating layer containing insulating heat-conducting functional powder. Wherein the nanorod-shaped aluminum borate loaded melamine borate is obtained through a microwave reaction among boric acid, aluminum hydroxide and melamine, and the aerogel layer and the phase change material layer are separated through the gravity effect. The phase change film material has excellent thermal conductivity, phase change latent heat capability, flame retardant property and electrical insulation property, and can be widely applied to intelligent thermal management of energy storage batteries and high-power chips.

Description

Technical Field

[0001] This invention belongs to the field of thermal management and thermal regulation materials technology, specifically relating to a phase change film material for thermal management of high-capacity energy storage batteries, its preparation method, and its application. Background Technology

[0002] Energy storage batteries are a core component of electric vehicles and an effective medium for addressing the challenges of volatility, intermittency, and difficulty in precise forecasting of renewable energy sources such as photovoltaics and wind power. In particular, large-capacity cells are the foundation for supporting long-term energy storage. However, large-capacity energy storage batteries are highly sensitive to temperature and must be maintained within a suitable temperature range to ensure optimal battery performance and safety. If the temperature is too low, the battery's response rate slows down, leading to decreased charging and discharging efficiency; at temperatures as low as -40°C, it may even fail to function properly. Conversely, excessively high temperatures accelerate battery aging, increase internal resistance, and may even trigger thermal runaway and other safety hazards. Therefore, thermal management of energy storage batteries is crucial for their stable and efficient operation.

[0003] Currently, widely used thermal management technologies for energy storage batteries include air cooling and liquid cooling. Air cooling utilizes airflow for heat dissipation, while liquid cooling achieves higher heat dissipation efficiency through liquid circulation. Patent CN202411935044.3 discloses a battery heat dissipation structure and packaging method based on phase change materials, including a cell unit, a heat dissipation partition, a shell, a heat dissipation material, and an insulating plate. The heat dissipation material fills the gaps between the cell unit and the heat dissipation partition, and between the cell unit and the shell. This patent uses phase change materials to fill the internal gaps of the battery, utilizing the latent heat of phase change after the phase change material is heated to quickly absorb the heat generated by the cell, significantly reducing the thermal response time and effectively preventing cell overheating. Patent CN202410218580.5 discloses a heat dissipation material for the shell of an energy storage battery and its preparation method. This patent coats modified disiloxane onto the surface of modified polycarbonate, utilizing polycarbonate with a long-branched cross-linked structure to enhance the material's heat resistance and heat dissipation effect. However, these thermal management materials lack the ability to simultaneously and synergistically enhance the battery's multiple functions of heat storage, heat dissipation, and flame retardancy, which greatly limits their practical application. Summary of the Invention

[0004] This invention addresses the problems of insufficient thermal conductivity, low heat utilization, and poor flame retardant performance of existing high-capacity energy storage batteries. It provides a phase change film material for thermal management of high-capacity energy storage batteries, its preparation method, and its application, thereby achieving the storage, efficient heat dissipation, and shielding against external heat in high-capacity energy storage batteries.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: (i) This invention provides a phase change film material for thermal management of high-capacity energy storage batteries. The film material has a three-layer structure: the upper layer is an aerogel layer containing aluminum borate nanorods supported on melamine borate; the middle layer is a phase change material layer containing gallium indium alloy; and the lower layer is a thermally conductive and insulating layer containing insulating and thermally conductive functional powder.

[0006] Furthermore, the nanorod-shaped aluminum borate supported on borate melamine is obtained through a microwave reaction between boric acid, aluminum hydroxide and melamine, and the aerogel layer and the phase change material layer achieve phase separation through gravity.

[0007] (II) The present invention also provides a method for preparing the phase change film material for thermal management of high-capacity energy storage batteries as described above, comprising the following steps: mixing insulating and thermally conductive functional powder with ethyl acetate, stirring evenly, adding tackifying resin, acrylic adhesive, curing agent and solubilizer, stirring evenly and then coating it onto a release film, curing and aging to obtain a thermally conductive insulating layer; adding boric acid, aluminum hydroxide and melamine into water, dispersing evenly, reacting in an ultrasonic microwave reactor, and freeze-drying to obtain nanorod-shaped aluminum borate-supported borate-melamine aerogel; mixing the nanorod-shaped aluminum borate-supported borate-melamine aerogel, gallium indium alloy and ethyl acetate, stirring evenly, adding tackifying resin, acrylic adhesive, curing agent and solubilizer, stirring evenly and then coating it onto a release film, standing, curing and aging to obtain an aerogel and phase change material composite layer; bonding the aerogel and phase change material composite layer to the thermally conductive insulating layer to obtain the phase change film material for thermal management of high-capacity energy storage batteries.

[0008] Furthermore, the insulating and thermally conductive functional powder comprises ammonium polyphosphate intercalated modified hydroxylated boron nitride and silicon carbide in a mass ratio of 1:0.2~0.5; the average particle size of the silicon carbide is 0.5~2 μm.

[0009] Furthermore, the preparation method of the ammonium polyphosphate intercalated modified hydroxylated boron nitride is as follows: boron nitride is dispersed in an alkaline solution, ammonium polyphosphate is added, ball milling and centrifugation are performed, the mixture is washed with water until neutral, and dried to obtain ammonium polyphosphate intercalated modified hydroxylated boron nitride; the mass ratio of the alkaline solution to boron nitride is 1:0.05~0.2, and the concentration of the alkaline solution is 20~50wt%; the mass ratio of the ammonium polyphosphate to boron nitride is 1:0.5~2; the average particle size of boron nitride is 2~20 μm.

[0010] Furthermore, the ball milling temperature is 50~80 ℃, and the ball milling time is 12~72 h.

[0011] Furthermore, in the preparation of the thermally conductive insulating layer: the mass ratio of the insulating and thermally conductive functional powder to ethyl acetate is 1:2~6; the mass ratio of the insulating and thermally conductive functional powder, tackifying resin, acrylic adhesive, curing agent and solubilizer is 1:0.5~10:2~10:0.02~0.1:0.02~0.1.

[0012] Furthermore, the mass ratio of boric acid, aluminum hydroxide, melamine, and water is 1:0.2~2:0.5~4:20~80; the particle size of the aluminum hydroxide is 2~10 μm; the microwave power of the ultrasonic microwave reactor is 200~500W; and the microwave reaction time is 5~20min.

[0013] Furthermore, in the preparation of the aerogel and phase change material composite layer: the mass ratio of the nanorod-shaped aluminum borate-supported borate melamine aerogel, gallium indium alloy, and ethyl acetate is 1:0.4~0.8:5~20; the mass ratio of the nanorod-shaped aluminum borate-supported borate melamine aerogel, tackifying resin, acrylic adhesive, curing agent, and solubilizer is 1:0.2~2:1~8:0.01~0.08:0.02~0.1; the gallium indium alloy is a gallium indium alloy or a gallium indium tin alloy; the standing temperature is 30~45℃, and the standing time is 2~8 h.

[0014] Furthermore, in the preparation of the thermally conductive insulating layer and the aerogel and phase change material composite layer, the tackifying resin, curing agent, and solubilizer used are the same, and the curing and aging processes have the same time and temperature. Specifically, the tackifying resin is a mixture of terpene resin and rosin resin, with a mass ratio of terpene resin to rosin resin of 1:1~2; the curing agent is L75 curing agent, and the solubilizer is propylene glycol methyl ether acetate; the curing temperature is 40~90℃, and the curing time is 2~5 min; the aging temperature is 30~60℃, and the aging time is 24~72 h.

[0015] (iii) The present invention also provides the application of the phase change film material described above in thermal management. Specifically, it can be applied to the thermal management of high-capacity energy storage batteries and the thermal management of high-power chips.

[0016] The beneficial effects of this invention are: (1) This invention constructs a three-layer structure for high-capacity energy storage battery thermal management phase change film material. The lower thermally conductive insulating layer enables rapid heat conduction from the energy storage battery. The middle layer, containing a gallium-indium alloy phase change material, stores heat and maintains the temperature of the energy storage battery in low-temperature environments. Meanwhile, the outer layer, a nanorod-shaped aluminum borate-supported melamine borate aerogel material, has excellent thermal insulation properties, preventing heat exchange between the phase change material layer and the outside environment, and ensuring the temperature and initial charge / discharge efficiency of the energy storage battery in low-temperature environments. During battery operation, as the ambient temperature increases, the phase change alloy absorbs heat and changes from a solid to a liquid state, undergoing volume expansion and viscosity reduction. It then enters the aerogel layer, filling it and significantly improving the thermal conductivity of the aerogel layer. This enables effective heat conduction from the aerogel layer to the outside, preventing a surge in internal battery heat. Furthermore, during the cooling process, the phase change alloy is separated from the aerogel again due to gravity and the weak interfacial interaction between the phase change alloy and the borate melamine loaded with nanorod-shaped aluminum borate. This allows for recycling and enables intelligent regulation of the battery's internal temperature.

[0017] (2) This invention uses a ball milling process to prepare ammonium polyphosphate-intercalated modified hydroxylated boron nitride. The ammonium polyphosphate effectively exfoliates the boron nitride, achieving the construction of small-particle-size, highly dispersed boron nitride sheets. The hydroxyl groups on the surface of the boron nitride facilitate its dispersion in the acrylic adhesive system. Simultaneously, the added small-particle-size silicon carbide particles fill the gaps between the boron nitride sheets, further improving the thermal conductivity of the acrylic adhesive. The intercalation of ammonium polyphosphate into the boron nitride sheets ensures stable dispersion of the ammonium polyphosphate in the acrylic adhesive, avoiding the migration and precipitation of ammonium polyphosphate in the adhesive as in traditional processes.

[0018] (3) The ammonium polyphosphate intercalating agent of the present invention can give acrylic adhesives high flame retardant properties, promote the dehydration of matrix materials into carbon, and the added silicon carbide and boron nitride have strong thermal stability, which can enhance the stability of the dehydrated carbon structure, maintain the heat insulation and air isolation function of the carbon layer, and realize the flame retardant properties of the thermally conductive adhesive layer.

[0019] (4) The upper aerogel layer material of the present invention is composed of nanorod-shaped aluminum borate loaded with borate melamine. The nanorod-shaped aluminum borate aerogel has higher mechanical strength than traditional aerogel, and the aluminum borate loaded with borate melamine can give the upper acrylic adhesive layer excellent flame retardant properties.

[0020] (5) The present invention uses the aqueous phase reaction of boric acid, melamine and aluminum hydroxide and freeze drying to prepare nanorod-shaped aluminum borate supported boric acid melamine composite, which avoids the high temperature and high pressure environment required by the traditional process and improves the economy and stability of the preparation process. Attached Figure Description

[0021] Figure 1SEM image of the nanorod-shaped aluminum borate supported on borate melamine prepared in Example 1; Figure 2 The diagrams show the thermally conductive insulating layer and the phase change film material for thermal management prepared in Example 1, where (a) is the thermally conductive insulating layer containing insulating and thermally conductive functional powder, and (b) is the phase change film material for thermal management. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 This embodiment provides a phase change film material for thermal management of high-capacity energy storage batteries, and the preparation method includes the following steps: Step 1: Prepare a thermally conductive insulating layer. 10 g of boron nitride with an average particle size of 5 μm was dispersed in 100 mL of 40 wt% sodium hydroxide solution and stirred at high speed for 1 h. Then, 10 g of ammonium polyphosphate was added, and the mixture was ball-milled at 80 °C for 48 h. After centrifugation, the mixture was washed with water until neutral and dried at 80 °C to obtain ammonium polyphosphate intercalated modified hydroxylated boron nitride.

[0024] 10 g of ammonium polyphosphate intercalated modified hydroxylated boron nitride and 4 g of silicon carbide with an average particle size of 1.6 μm were added to 70 g of ethyl acetate and stirred evenly. Then, 42 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:1), 84 g of acrylic adhesive, 0.7 g of curing agent (L75) and 0.5 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, cured at 70 ℃ for 3 min and aged at 40 ℃ for 48 h to obtain a thermally conductive insulating layer containing insulating and thermally conductive functional powder.

[0025] Step 2: Preparation of nanorod-shaped aluminum borate-supported boric acid-melamine aerogel: 10 g boric acid, 5 g aluminum hydroxide with an average particle size of 4 μm and 20 g melamine were added to 260 mL of deionized water, stirred and dispersed evenly, placed in an ultrasonic microwave reactor, microwave power was set to 300 W, reaction was carried out for 8 min, and then freeze-dried to obtain nanorod-shaped aluminum borate-supported melamine borate aerogel.

[0026] Step 3: Preparation of the aerogel and phase change material composite layer: 10 g of aluminum borate nanorod-shaped borate-supported borate melamine aerogel and 4 g of gallium indium alloy were added to 60 g of ethyl acetate and stirred evenly. Then, 4 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:1), 40 g of acrylic adhesive, 0.2 g of curing agent (L75) and 0.4 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, allowed to stand at 35 °C for 5 h, cured at 60 °C for 2 min, and aged at 30 °C for 72 h to obtain an aerogel and phase change material composite layer.

[0027] Step 4: Preparation of phase change film materials A composite layer of aerogel and phase change material is bonded to a thermally conductive insulating layer containing insulating and thermally conductive functional powder to obtain a phase change film material for thermal management.

[0028] Example 2 This embodiment provides a phase change film material for thermal management of high-capacity energy storage batteries, and the preparation method includes the following steps: Step 1: Prepare a thermally conductive insulating layer. 15 g of boron nitride with an average particle size of 10 μm was dispersed in 150 mL of 20 wt% sodium hydroxide solution and stirred at high speed for 1 h. 20 g of ammonium polyphosphate was added, and the mixture was ball-milled at 50 ℃ for 36 h. After centrifugation, the mixture was washed with water until neutral and dried at 85 ℃ to obtain ammonium polyphosphate intercalated modified hydroxylated boron nitride. 15 g of ammonium polyphosphate intercalated modified hydroxylated boron nitride and 5 g of silicon carbide with an average particle size of 1.2 μm were added to 80 g of ethyl acetate and stirred evenly. Then, 50 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 66 g of acrylic adhesive, 0.8 g of curing agent (L75) and 0.6 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, cured at 60 ℃ for 2 min and aged at 30 ℃ for 72 h to obtain a thermally conductive insulating layer containing insulating and thermally conductive functional powder.

[0029] Step 2: Preparation of nanorod-shaped aluminum borate-supported boric acid-melamine aerogel: 15 g boric acid, 8 g aluminum hydroxide with an average particle size of 5 μm and 25 g melamine were added to 1000 mL of deionized water, stirred and dispersed evenly, placed in an ultrasonic microwave reactor, microwave power was set to 200 W, reaction was carried out for 15 min, and then freeze-dried to obtain nanorod-shaped aluminum borate-supported melamine borate aerogel.

[0030] Step 3: Preparation of the aerogel and phase change material composite layer: 15 g of aluminum borate nanorod-shaped borate-supported borate melamine aerogel and 7 g of gallium indium tin alloy were added to 90 g of ethyl acetate and stirred evenly. Then, 8 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 50 g of acrylic adhesive, 0.3 g of curing agent (L75) and 0.6 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, allowed to stand at 40 °C for 6 h, cured at 70 °C for 3 min, and aged at 40 °C for 48 h to obtain a composite layer of aerogel and phase change material.

[0031] Step 4: Preparation of phase change film materials A composite layer of aerogel and phase change material is bonded to a thermally conductive insulating layer containing insulating and thermally conductive functional powder to obtain a phase change film material for thermal management.

[0032] Example 3 This embodiment provides a phase change film material for thermal management of high-capacity energy storage batteries, and the preparation method includes the following steps: Step 1: Prepare a thermally conductive insulating layer. 20 g of boron nitride with an average particle size of 15 μm was dispersed in 250 mL of 30 wt% sodium hydroxide solution and stirred at high speed for 1 h. 30 g of ammonium polyphosphate was added, and the mixture was ball-milled at 60 ℃ for 24 h. After centrifugation, the mixture was washed with water until neutral and dried at 75 ℃ to obtain ammonium polyphosphate intercalated modified hydroxylated boron nitride. 20 g of ammonium polyphosphate intercalated modified hydroxylated boron nitride and 10 g of silicon carbide with an average particle size of 1.0 μm were added to 90 g of ethyl acetate and stirred evenly. Then, 65 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 80 g of acrylic adhesive, 0.6 g of curing agent (L75) and 0.8 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, cured at 50 ℃ for 4 min and aged at 50 ℃ for 36 h to obtain a thermally conductive insulating layer containing insulating and thermally conductive functional powder.

[0033] Step 2: Preparation of nanorod-shaped aluminum borate-supported boric acid-melamine aerogel: 20 g boric acid, 12 g aluminum hydroxide with an average particle size of 2.5 μm and 40 g melamine were added to 1200 mL of deionized water, stirred and dispersed evenly, placed in an ultrasonic microwave reactor, microwave power was set to 400 W, reaction was carried out for 10 min, and then freeze-dried to obtain nanorod-shaped aluminum borate-supported melamine borate aerogel.

[0034] Step 3: Preparation of the aerogel and phase change material composite layer: 20 g of aluminum borate nanorod-shaped borate-supported borate melamine aerogel and 15 g of gallium indium alloy were added to 150 g of ethyl acetate and stirred evenly. Then, 15 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:1), 60 g of acrylic adhesive, 0.8 g of curing agent (L75) and 1.0 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, allowed to stand at 45 ℃ for 6 h, cured at 80 ℃ for 5 min, and aged at 50 ℃ for 36 h to obtain the aerogel and phase change material composite.

[0035] Step 4: Preparation of phase change film materials A composite layer of aerogel and phase change material is bonded to a thermally conductive insulating layer containing insulating and thermally conductive functional powder to obtain a phase change film material for thermal management.

[0036] Example 4 This embodiment provides a phase change film material for thermal management of high-capacity energy storage batteries, and the preparation method includes the following steps: Step 1: Prepare a thermally conductive insulating layer. 25 g of boron nitride with an average particle size of 15 μm was dispersed in 300 mL of 50 wt% sodium hydroxide solution and stirred at high speed for 1 h. 30 g of ammonium polyphosphate was added, and the mixture was ball-milled at 70 ℃ for 72 h. After centrifugation, the mixture was washed with water until neutral and dried at 80 ℃ to obtain ammonium polyphosphate intercalated modified hydroxylated boron nitride. 25 g of ammonium polyphosphate intercalated modified hydroxylated boron nitride and 10 g of silicon carbide with an average particle size of 1.8 μm were added to 140 g of ethyl acetate and stirred evenly. Then, 70 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 100 g of acrylic adhesive, 1.5 g of curing agent (L75) and 1.6 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, cured at 80 ℃ for 3 min and aged at 60 ℃ for 24 h to obtain a thermally conductive insulating layer containing insulating and thermally conductive functional powder.

[0037] Step 2: Preparation of nanorod-shaped aluminum borate-supported boric acid-melamine aerogel: 25 g boric acid, 15 g aluminum hydroxide with an average particle size of 8 μm and 40 g melamine were added to 2000 mL of deionized water, stirred and dispersed evenly, placed in an ultrasonic microwave reactor, microwave power was set to 500 W, reaction was carried out for 20 min, and then freeze-dried to obtain nanorod-shaped aluminum borate-supported melamine borate aerogel.

[0038] Step 3: Preparation of the aerogel and phase change material composite layer: 25 g of aluminum borate nanorod-shaped borate-supported borate melamine aerogel and 20 g of gallium indium tin alloy were added to 200 g of ethyl acetate and stirred evenly. Then, 20 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 80 g of acrylic adhesive, 1.2 g of curing agent (L75) and 1.5 g of solubilizer (propylene glycol methyl ether acetate) were added and stirred evenly. The mixture was then coated onto a release film, allowed to stand at 35 ℃ for 8 h, cured at 90 ℃ for 3 min, and aged at 60 ℃ for 24 h to obtain an aerogel and phase change material composite layer.

[0039] Step 4: Preparation of phase change film materials A composite layer of aerogel and phase change material is bonded to a thermally conductive insulating layer containing insulating and thermally conductive functional powder to obtain a phase change film material for thermal management.

[0040] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that ammonium polyphosphate intercalation is not used.

[0041] In step one, the addition of ammonium polyphosphate is omitted. 20 g of boron nitride with an average particle size of 15 μm is dispersed in 250 mL of 30 wt% sodium hydroxide solution, stirred at high speed for 1 h, ball-milled at 60 ℃ for 24 h, centrifuged, washed with water until neutral, and dried at 75 ℃. The remaining operations are the same as in Example 1.

[0042] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that silicon carbide is not added.

[0043] In step one, the addition of silicon carbide is omitted. 10 g of ammonium polyphosphate intercalated modified hydroxylated boron nitride is added to 70 g of ethyl acetate and stirred evenly. Then, 42 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 84 g of acrylic adhesive, 0.7 g of curing agent (L75) and 0.5 g of solubilizer (propylene glycol methyl ether acetate) are added and stirred evenly. The mixture is then applied to a release film, cured at 70 °C for 3 min, and aged at 40 °C for 48 h to obtain a thermally conductive insulating layer containing insulating and thermally conductive functional powder. The remaining operations are the same as in Example 1.

[0044] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 is not freeze-dried.

[0045] In step two, the freeze-drying operation is omitted. 10 g of boric acid, 5 g of aluminum hydroxide with an average particle size of 5 μm and 20 g of melamine are added to 500 mL of deionized water, stirred and dispersed evenly, and placed in an ultrasonic microwave reactor. The microwave power is set to 300 W and the reaction is carried out for 8 min. The remaining operations are the same as in Example 1.

[0046] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that there is no phase transformation alloy.

[0047] In step three, the addition of gallium-indium alloy is omitted. 10 g of aluminum borate nanorod-shaped borate-supported borate melamine aerogel is added to 40 g of ethyl acetate and stirred evenly. Then, 4 g of tackifying resin (terpene resin and rosin resin in a mass ratio of 1:2), 40 g of acrylic adhesive, 0.2 g of curing agent (L75), and 0.4 g of solubilizer (propylene glycol methyl ether acetate) are added and stirred evenly. The mixture is then coated onto a release film, allowed to stand at 39 ℃ for 5 h, cured at 60 ℃ for 2 min, and aged at 30 ℃ for 72 h to obtain an aerogel and phase change material composite layer. The remaining operations are the same as in Example 1.

[0048] Performance testing and results: The following performance tests were performed on the thermal management film materials prepared in Examples 1-4 and Comparative Examples 1-4: 1) Thermal conductivity: Measured according to ASTM D5470, with hot end temperatures of 30℃ and 80℃, cold end temperature of 20℃, and membrane material stacked to 1.0 mm.

[0049] 2) Latent heat of phase change: determined by DSC method.

[0050] 3) Phase change material permeability: Tested in a forced-air drying oven, the mass reduction rate of the membrane material after being placed at 60℃ for 120 minutes was measured.

[0051] 4) Flame retardant performance: The oxygen index (LOI) (GB / T2406) and vertical burning test (ASTM D4804) are used.

[0052] 5) Peel strength: Tested according to GBT3917.2-2009 method, with a sample size of 182 mm × 50 mm, and peel test at 180°.

[0053] The test results are shown in Table 1.

[0054] Table 1: Test results of Examples 1-4 and Comparative Examples 1-4

[0055] As shown in Table 1, the phase change film material provided by this invention achieves significant and balanced optimization in overall performance compared to the comparative example. Regarding thermal management, the material of this invention exhibits superior performance in both the absorption and storage of heat (latent heat of phase change) and the dissipation of heat at high temperatures (thermal conductivity), effectively buffering battery temperature rise and promoting thermal diffusion. In terms of safety performance, the material of this invention achieves a VTM-0 flame retardancy rating, and its limiting oxygen index remains at a high level, indicating excellent anti-flammability and providing a higher level of safety for battery systems. This invention combines high latent heat, high thermal conductivity, high flame retardancy, and low leakage characteristics into a single unit. This comprehensive improvement in overall performance makes the material of this invention more suitable for high-capacity energy storage batteries with stringent safety and thermal management requirements.

[0056] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A phase change film material for thermal management of high-capacity energy storage batteries, characterized in that, The membrane material has a three-layer structure: the upper layer is an aerogel layer containing aluminum borate nanorods supported on borate melamine, the middle layer is a phase change material layer containing gallium indium alloy, and the lower layer is a thermally conductive and insulating layer containing insulating and thermally conductive functional powder.

2. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 1, characterized in that, Includes the following steps: The insulating and thermally conductive functional powder is mixed with ethyl acetate and stirred evenly. Then, tackifying resin, acrylic glue, curing agent and solubilizer are added and stirred evenly. The mixture is then applied to the release film and cured and aged to obtain a thermally conductive and insulating layer. Boric acid, aluminum hydroxide, and melamine were added to water, dispersed evenly, and reacted in an ultrasonic microwave reactor. After freeze-drying, nanorod-shaped aluminum borate-supported melamine borate aerogel was obtained. Nanorod-shaped aluminum borate supported borate melamine aerogel, gallium indium alloy and ethyl acetate were mixed and stirred evenly. Tackifying resin, acrylic glue, curing agent and solubilizer were added and stirred evenly. The mixture was then coated on a release film, allowed to stand, cured and aged to obtain a composite layer of aerogel and phase change material. By bonding an aerogel and phase change material composite layer to a thermally conductive insulating layer, a phase change film material for thermal management of high-capacity energy storage batteries is obtained.

3. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 2, characterized in that, The insulating and thermally conductive functional powder comprises ammonium polyphosphate intercalated modified hydroxylated boron nitride and silicon carbide in a mass ratio of 1:0.2~0.5; the average particle size of the silicon carbide is 0.5~2 μm.

4. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 3, characterized in that, The preparation method of the ammonium polyphosphate intercalated modified hydroxylated boron nitride is as follows: Boron nitride was dispersed in an alkaline solution, and ammonium polyphosphate was added. The mixture was then ball-milled and centrifuged to obtain ammonium polyphosphate intercalated modified hydroxylated boron nitride. The mass ratio of the alkaline solution to boron nitride was 1:0.05~0.2, and the concentration of the alkaline solution was 20~50wt%. The mass ratio of the ammonium polyphosphate to boron nitride was 1:0.5~2. The average particle size of the boron nitride was 2~20 μm.

5. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 4, characterized in that, The ball milling temperature is 50~80 ℃, and the ball milling time is 12~72 h.

6. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 2, characterized in that, In the preparation of the thermally conductive insulating layer: The mass ratio of insulating and thermally conductive functional powder to ethyl acetate is 1:2~6; the mass ratio of insulating and thermally conductive functional powder, tackifying resin, acrylic adhesive, curing agent and solubilizer is 1:0.5~10:2~10:0.02~0.1:0.02~0.

1.

7. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 2, characterized in that, The mass ratio of boric acid, aluminum hydroxide, melamine, and water is 1:0.2~2:0.5~4:20~80; The aluminum hydroxide has a particle size of 2-10 μm, the ultrasonic microwave reactor has a microwave power of 200-500W, and the microwave reaction time is 5-20 min.

8. The method for preparing phase change film material for thermal management of high-capacity energy storage batteries according to claim 2, characterized in that, In the preparation of the aerogel and phase change material composite layer: The mass ratio of the nanorod-shaped aluminum borate-supported borate melamine aerogel, gallium-indium alloy, and ethyl acetate is 1:0.4~0.8:5~20; the mass ratio of the nanorod-shaped aluminum borate-supported borate melamine aerogel, tackifying resin, acrylic adhesive, curing agent, and solubilizer is 1:0.2~2:1~8:0.01~0.08:0.02~0.

1. The gallium-indium alloy is a gallium-indium alloy or a gallium-indium-tin alloy; the settling temperature is 30~45℃ and the settling time is 2~8 h.

9. The method for preparing the phase change film material for thermal management of high-capacity energy storage batteries according to claim 2, characterized in that, In the preparation of the thermally conductive insulating layer and the composite layer of aerogel and phase change material: The tackifying resin is a mixture of terpene resin and rosin resin, the curing agent is L75 curing agent, and the solubilizer is propylene glycol methyl ether acetate. The curing temperature is 40~90℃ and the curing time is 2~5 min; the aging temperature is 30~60℃ and the aging time is 24~72 h.

10. The application of the phase change film material according to claim 1 in thermal management of high-capacity energy storage batteries and thermal management of high-power chips.

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