New energy power battery low-temperature heating mica plate and preparation method thereof

Abstract

The invention relates to the technical field of automobile batteries, and discloses a new energy power battery low-temperature heating mica plate and a preparation method thereof.The new energy power battery low-temperature heating mica plate comprises the following materials: a mica plate base material which is prepared by using phlogopite paper as a main raw material and treating the phlogopite paper with a treating fluid 1 prepared from high-temperature-resistant organic silica gel, aerogel and a silane coupling agent; the low-temperature self-heating coating is uniformly coated on the surface of the mica plate base material by a treating fluid 2 which is prepared from high-temperature-resistant organic silica gel and graphene as main components; and the PTC composite heating sheet is embedded between the low-temperature self-heating coating and the mica plate base material and is used for realizing the self-heating function of the plate in a low-temperature environment. By adopting the phlogopite paper as a main base material and performing pretreatment, the thermal insulation performance of the mica plate is improved, meanwhile, the material is endowed with excellent thermal barrier performance, the heat loss of a battery pack in a low-temperature environment is effectively slowed down, and the stable operation of a battery in a proper temperature range is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive batteries, and particularly to a low-temperature heating mica plate for new energy power batteries and a preparation method thereof. Background Art

[0002] As an excellent natural mineral material, mica is widely used in the fields of electronic components, electrical equipment, and new energy due to its high heat resistance, low thermal conductivity, and excellent electrical insulation properties. Traditional mica plates are usually made by laminating natural mica and combining with silicone binders to form plates, which show stable performance in terms of heat insulation, electrical insulation, and high-temperature resistance. Especially in the thermal management system of electric vehicle batteries, mica plates are often used as key materials for heat insulation and insulation due to their high temperature resistance and good heat barrier characteristics. However, with the continuous development of electric vehicle technology, the requirements for thermal management and safety performance of battery packs are becoming increasingly stringent, and the limitations of existing mica plates in high-temperature heat insulation and electrical insulation performance in high-humidity environments are gradually emerging.

[0003] Although existing mica plates can meet the basic requirements of heat insulation and insulation, there are still some deficiencies in the high-temperature operation of electric vehicle batteries and extreme environments (such as high-humidity environments or large temperature fluctuations). For example, under continuous high-temperature working conditions, the heat barrier ability of traditional mica plates is limited, making it difficult to effectively reduce the heat diffusion rate when the battery undergoes thermal runaway, thus increasing the safety risk. In addition, mica materials are sensitive to humidity, and their insulation performance will decline in high-humidity environments, which may cause short circuits or other hidden dangers inside the battery pack. At the same time, in the processing of traditional mica plates, the single coating and curing process may lead to uneven coating surfaces or local defects, reducing their stability and safety during long-term use. Therefore, to address these problems in the application of electric vehicle batteries, it is necessary to further functionally modify the mica plates to optimize their heat insulation, insulation, and moisture resistance properties to meet the thermal management and safety requirements under complex working conditions. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a low-temperature heating mica plate for new energy power batteries and a preparation method thereof, which solves the problems of insufficient high-temperature heat insulation efficiency, decreased insulation performance in high-humidity environments, and poor coating stability of traditional mica plates.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A low-temperature heating mica plate for new energy power batteries, comprising the following materials: A mica plate substrate, which is made from phlogopite paper as the main raw material and treated with treatment liquid 1 prepared from high-temperature resistant silicone rubber, aerogel, and silane coupling agent. A low-temperature self-heating coating, which is formed by uniformly coating treatment liquid 2 mainly composed of high-temperature resistant silicone rubber and graphene on the surface of the mica plate substrate. The PTC composite heating sheet is embedded between the low-temperature self-heating coating and the mica board substrate, and is used to realize the self-heating function of the board in a low-temperature environment; Among them, the mica board substrate is treated with phlogopite paper, which can improve the mechanical strength, heat insulation performance and high-temperature resistance characteristics of the material. After being pretreated with treatment liquid 1, its heat insulation and heat preservation effects are significantly enhanced. The low-temperature self-heating coating realizes the efficient transfer and uniform distribution of heat through the high thermal conductivity of graphene and the adhesion performance of high-temperature resistant silicone rubber. The embedded PTC composite heating sheet can provide stable heat in a low-temperature environment, avoid the performance attenuation of the battery pack at low temperature, and improve safety and endurance.

[0006] Preferably, the treatment liquid 1 includes the following component materials: High-temperature resistant silicone rubber: 70% - 90%; Aerogel: 25% - 45%; Silane coupling agent: 8% - 10%; Among them, the component combination of treatment liquid 1 makes the treatment effect of phlogopite paper more uniform and the heat insulation performance significantly improved. High-temperature resistant silicone rubber is the main substrate, endowing the material with high heat resistance and adhesion; aerogel has low thermal conductivity and can enhance the heat insulation effect; silane coupling agent improves the adhesion between the treatment liquid and phlogopite paper. This ratio ensures the optimal comprehensive performance of the material.

[0007] Preferably, the treatment liquid 2 includes the following component materials: High-temperature resistant silicone rubber: 20% - 30%; Graphene: 15% - 25%; Among them, treatment liquid 2 combines the high thermal conductivity of graphene with the adhesion performance of high-temperature resistant silicone rubber to provide the mica board with efficient heat conduction and stable heating functions. Graphene can quickly transfer heat and release it evenly, while high-temperature resistant silicone rubber ensures the adhesion and durability of the coating. This ratio takes into account both the heat conduction performance and the material stability.

[0008] A preparation method for a low-temperature heating mica board of a new energy power battery includes the following steps: S1. Prepare treatment liquid 1: Mix high-temperature resistant silicone rubber, aerogel, kaolin powder and silane coupling agent in a blender according to the ratio for 60 minutes to form a uniform treatment liquid 1; S2. Pretreat the mica paper: Uniformly coat the treatment liquid 1 on the surface of phlogopite paper by dipping; S3. Hot press the mica board: Place the pretreated mica paper in a hot press and hot press for more than 30 minutes to form a mica board substrate; S4. Prepare treatment liquid 2: Put high-temperature resistant silicone rubber and graphene into a blender according to the ratio and mix for 60 minutes to form a uniform treatment liquid 2; S5. Coating with a low-temperature self-heating coating: The treatment liquid 2 is evenly coated on the surface of the mica plate substrate by using a slit coating process, and at the same time, a PTC composite heating sheet is embedded. S6. Drying: A zoned drying method is adopted, and three temperature zones with different temperature ranges are set for drying. Among them, in step S1, thorough stirring ensures the uniform dispersion of the components of treatment liquid 1, making the heat insulation performance of the mica paper consistent after pretreatment; in step S2, controlling the dipping speed within the range of 3 m / min to 5 m / min helps the treatment liquid to be evenly coated and avoids glue overflow or uneven coating; in step S3, the hot pressing conditions optimize the mechanical properties and interlayer bonding strength of the mica plate substrate; in step S4, graphene and silicone rubber are fully mixed when stirring treatment liquid 2 to ensure the thermal conductivity and stability of the coating; in step S5, the slit coating process enables precise control of the coating thickness, and embedding the PTC heating sheet endows the mica plate with low-temperature heating ability; in step S6, zoned drying avoids uneven curing of the coating and ensures the overall heating efficiency and coating quality.

[0009] Preferably, in step S1, the stirring speed of the stirrer is ≥500 r / min.

[0010] Preferably, in step S2, the dipping speed of the dipping method is controlled within the range of 3 m / min to 5 m / min. Among them, controlling the dipping speed within the range of 3 - 5 m / min can ensure that the phlogopite paper is evenly coated with the treatment liquid and avoid the occurrence of glue overflow (too slow speed) or coating depression (too fast speed), thus ensuring the processing quality of the mica plate.

[0011] Preferably, in step S3, the hot pressing temperature of the hot press is 180°C to 260°C, and the hot pressing pressure is 1.9 MPa to 2.6 MPa. Among them, the optimized control of the hot pressing temperature, pressure, and time ensures the interlayer bonding strength, mechanical properties, and heat insulation effect of the mica plate substrate, and avoids delamination or deformation problems caused by too high temperature or pressure.

[0012] Preferably, in step S4, the stirring speed of the stirrer is ≥500 r / min. Among them, a stirring speed of ≥500 r / min can ensure the uniform dispersion of the treatment liquid components and avoid uneven surface treatment of the mica paper due to insufficient mixing, thus affecting the heat insulation performance.

[0013] Preferably, in step S5, the slit coating thickness is 0.5 mm ± 0.1 mm, and the coating speed is 6 m / min to 8 m / min. Among them, the control of the coating thickness and coating speed can ensure the uniformity of the low-temperature self-heating coating, and at the same time ensure the stability of the thermal conductivity and heating effect.

[0014] Preferably, in the step S6, the temperature range includes: The first temperature zone: 80°C to 100°C; The second temperature zone: 130°C to 150°C; The third temperature zone: 100°C to 110°C; Among them, the temperature control of the partition drying ensures the gradual curing of the coating, avoids the appearance of bubbles or unevenness in the coating, and at the same time improves the overall heating effect and the durability of the coating.

[0015] The present invention provides a low-temperature heating mica plate for a new energy power battery and a preparation method thereof. It has the following beneficial effects: 1. By using phlogopite paper as the main base material and pretreating it with treatment liquid 1, the present invention effectively improves the heat insulation and heat preservation performance of the mica plate. The mica paper is treated with a special ratio of high-temperature resistant silicone rubber, aerogel, kaolin powder and silane coupling agent, endowing the material with more excellent heat barrier performance. Compared with the problem of low heat management efficiency of traditional mica plates in the prior art, the present invention solves the deficiency of rapid heat dissipation of the battery pack in a low-temperature environment, ensuring that the battery can operate within an appropriate temperature range.

[0016] 2. The present invention evenly coats treatment liquid 2 on the surface of the mica plate and embeds a PTC composite heating sheet to achieve stable heating in a low-temperature environment. Graphene has excellent thermal conductivity and can quickly transfer heat to the inside of the battery pack. At the same time, the PTC heating sheet has a temperature control function to avoid overheating problems. Compared with the prior art solution that relies on an external heating device to raise the temperature of the battery pack, the present invention provides a self-heating type thermal management material, solving the deficiencies of a complex external heating system and high energy consumption.

[0017] 3. By optimizing the hot pressing forming process and the partition drying technology, the present invention makes the structure of the mica plate more stable, the coating adheres evenly, and avoids problems such as interlayer peeling or coating bubbles. The mica plate adopts a slit coating technology to accurately control the coating thickness, and combines the partition drying method to gradually cure the heating coating, improving the processing quality of the material. Compared with the materials with poor coating adhesion and poor thermal cycling performance in the prior art, the present invention significantly improves the durability and long-term use performance of the material, and at the same time reduces the risk of quality fluctuations during the production process. Description of the Drawings

[0018] Figure 1 It is a method step diagram of the present invention; Figure 2 It is a process flow diagram of the present invention. Detailed Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Please refer to the attached Figure 1 - attached Figure 2 : Example 1: Preparation of mica plate substrate and improvement of heat insulation performance Take phlogopite paper and cut it into pieces of 200mm×200mm for standby.

[0021] Prepare treatment liquid 1 in proportion: 80 parts of high-temperature resistant silicone rubber, 35 parts of aerogel, an appropriate amount of kaolin powder, and 9 parts of silane coupling agent. Use a stirrer to mix at a speed of 500r / min for 60 minutes to ensure that the liquid is uniform and the color is consistent.

[0022] Pour treatment liquid 1 into the impregnating equipment, set the impregnating speed to 4m / min, and impregnate the mica paper so that the surface is evenly covered with the treatment liquid.

[0023] Hot press molding. Heat press the impregnated mica paper within the temperature range of 180°C to 260°C, control the pressure at 2.2MPa, and set the hot press time to 35 minutes to obtain the mica plate substrate.

[0024] Performance test: Use an infrared thermal imager to detect the heat insulation effect of the mica plate substrate. The measured thermal conductivity is 0.13W / (m·K), which is significantly better than that of the untreated mica paper, which is 0.25W / (m·K).

[0025] Example 2: Preparation of heating coating and mica plate forming Prepare treatment liquid 2: Add 25 parts of high-temperature resistant silicone rubber and 20 parts of graphene to the stirrer in proportion, set the stirring speed to 500r / min, and stir for 60 minutes until a uniform viscous liquid is formed.

[0026] Take the mica plate substrate that has completed hot press molding, put it into the coating machine, and use the slit coating process to evenly coat treatment liquid 2 on the surface of the mica plate. Control the coating thickness to 0.5mm±0.1mm. Set the coating speed to 7m / min to ensure that there are no obvious bubbles in the coating.

[0027] During the coating process, embed the PTC composite heating sheet between the mica plate and the coating. After the heating sheet is fixed, continue coating until it is completely covered.

[0028] Drying treatment: The coating is cured by a zone drying method. The temperature of the first zone is set at 90 °C, the second zone is set at 140 °C, and the third zone is reduced to 105 °C. The drying time for each zone is 10 minutes.

[0029] Product testing: Use an incubator to simulate a low-temperature environment of -20 °C, turn on the PTC heating element, and the heat is evenly released through the coating, and the temperature around the battery is stabilized at 25 °C.

[0030] Example 3: Influence of zone drying on coating stability Prepare treatment liquid 2. According to the ratio in Example 2, mix high-temperature resistant silicone rubber and graphene, and stir for 60 minutes at a stirring speed of 500 r / min.

[0031] Coat treatment liquid 2 using the slit coating process. The coating thickness is maintained at 0.5 mm ± 0.1 mm, and the speed is set at 6.5 m / min for uniform coating.

[0032] Zone drying: The coated mica plate substrate is sequentially passed through three temperature zones. The first temperature zone is set at 85 °C, the second temperature zone is 140 °C, and the third temperature zone is 105 °C. The drying time for each zone is 12 minutes.

[0033] Detect the coating performance: Conduct a peel test on the product, and the adhesion force does not decrease significantly. The coating thickness is stable, and no obvious bubbles are found. Perform a high-low temperature cycle test (-20 °C to 80 °C, 30 cycles) on the material, and the coating does not peel off, and the thermal conductivity does not decay significantly.

[0034] Example 4: Comprehensive performance test of mica plate The mica plates prepared through Example 1 and Example 2 are assembled into a battery pack. The battery pack is placed in a low-temperature environment of -20 °C for operation.

[0035] Turn on the PTC heating element, set the current at 2.5 A, and the voltage at 12 V. The heating element starts to heat stably within 3 minutes, and the heat is evenly transferred to the surroundings of the battery through the graphene coating.

[0036] Use an infrared thermal imager to observe the heat distribution. The temperature inside the battery pack is stabilized at 28 °C, and there is no obvious temperature difference. Conduct a continuous heating test for 30 minutes, and the heat remains stable.

[0037] Example 5: Comparison of heat generation efficiency and heat loss Under the conditions of the same size and shape, test the thermal performance of a traditional mica plate (untreated) and the mica plate of the present invention respectively.

[0038] Place the two mica plates in a heat flowmeter to detect heat loss. The heat loss of the traditional mica plate is 25 W / m 2 , and the heat loss of the mica plate of the present invention is reduced to 10 W / m 2 .

[0039] Under the same low - temperature conditions, the mica board of the present invention can raise the temperature around the battery to 25°C within 2 minutes, while the traditional mica board takes more than 5 minutes.

[0040] Comparative Example 1: Mica board not pretreated with Treatment Liquid 1 Directly take phlogopite paper, cut it into pieces of 200mm×200mm, and there is no dipping treatment with Treatment Liquid 1.

[0041] Place the phlogopite paper directly in a hot press, set the hot - pressing temperature at 200°C, the pressure at 2.0 MPa, and the time at 30 minutes to make the mica - board substrate.

[0042] This mica board is not treated with Treatment Liquid 1 and does not add aerogel or silane coupling agent.

[0043] The obtained mica board is used to test its heat - insulation performance.

[0044] Comparative Example 2: The heating coating does not contain graphene Prepare Treatment Liquid 2, only use high - temperature - resistant silicone rubber (30 parts), do not add graphene, and directly use it as the heating - coating material.

[0045] The coating steps are the same as those in Example 2. Uniformly coat Treatment Liquid 2 on the surface of the mica - board substrate, control the thickness at 0.5mm ± 0.1mm, and the coating speed at 7m / min.

[0046] After embedding the PTC composite heating sheet, carry out zoned drying. The temperature zones are set as: the first temperature zone is 90°C, the second temperature zone is 140°C, and the third temperature zone is 105°C. The drying time for each zone is 10 minutes.

[0047] The obtained mica board is used to test the low - temperature heating effect and heat - transfer performance.

[0048] Comparative Example 3: Preparation of the coating without zoned drying Prepare Treatment Liquid 2 according to the ratio in Example 3 (25 parts of high - temperature - resistant silicone rubber, 20 parts of graphene), with a stirring speed of 500r / min and a stirring time of 60 minutes to form a uniform treatment liquid.

[0049] Adopt the slit - coating process to uniformly coat Treatment Liquid 2 on the surface of the mica - board substrate, with a coating speed of 6.5m / min and the thickness controlled at 0.5mm ± 0.1mm.

[0050] After coating is completed, adopt a single - temperature - zone drying method, set the temperature at 150°C, and the drying time at 30 minutes, without zoned drying.

[0051] The obtained mica board is used to detect the uniformity, adhesion and heating performance of the coating.

[0052] Comparative Example 4: Mica plate with PTC heating sheet not embedded in the coating Using the process flow of Example 2, the preparation of Treatment Liquid 1 and Treatment Liquid 2 is exactly the same.

[0053] When coating Treatment Liquid 2, the PTC composite heating sheet was not embedded, and the coating completely covered the surface of the mica plate substrate, with the thickness controlled at 0.5 mm ± 0.1 mm.

[0054] The coated mica plate was dried in zones, with the temperature zones set as the first zone at 90 °C, the second zone at 140 °C, and the third zone at 105 °C, and the drying time for each zone was 10 minutes.

[0055] The obtained mica plate was used to test the low-temperature heating effect.

[0056] Comparative Example 5: Deviation in coating thickness and coating speed Prepare Treatment Liquid 2 with the same formulation and stirring parameters as in Example 2.

[0057] When coating Treatment Liquid 2, adjust the coating thickness to 0.8 mm and the coating speed to 4 m / min.

[0058] After embedding the PTC composite heating sheet, it was processed according to the zone drying process, with the temperature zones being 90 °C, 140 °C, and 105 °C respectively, and the time for each zone being 10 minutes.

[0059] The obtained mica plate was used to test the thermal conductivity and processing quality of the coating.

[0060] Comparative Example 6: Comparison of thermal properties of traditional mica plates Use common untreated mica plate materials on the market, without any coating and processing of Treatment Liquid 1 or Treatment Liquid 2, and directly assemble the mica plate into the battery pack.

[0061] Place it in a low-temperature environment (-20 °C), and heat the battery pack through an external heating device to simulate the existing thermal management method.

[0062] During the test, use a thermal flowmeter to measure the heat transfer effect of the mica plate and record the temperature change inside the battery pack.

[0063] Experiment 1: Test on the heat insulation and heat preservation performance of the mica plate substrate Experiment purpose: Verify whether the heat insulation and heat preservation effect of the mica plate substrate is significantly improved after pretreatment with Treatment Liquid 1, and compare the heat insulation performance of Example 1 and Comparative Example 1.

[0064] Experiment equipment and materials: Infrared thermal barrier tester.

[0065] Temperature source device (stable temperature control at 100 °C).

[0066] Experimental samples: mica plate substrates prepared in Example 1 and mica plate substrates prepared in Comparative Example 1 (5 pieces each, with dimensions of 100 mm × 100 mm).

[0067] Thermocouple temperature sensor.

[0068] Experimental procedures: Set up the infrared thermal barrier tester, set the temperature source device to a constant 100 °C, and wait for the device to operate stably.

[0069] Cover the mica plate sample (100 mm × 100 mm) prepared in Example 1 on the surface of the temperature source. Fix the sensor 10 mm above the sample to measure the temperature after passing through the mica plate.

[0070] Start the tester, record the sensor temperature value, read the data every 5 seconds, and record for 30 seconds. Repeat the test 3 times and take the average as the final result.

[0071] Follow the same steps to test the sample of Comparative Example 1 and record the corresponding data.

[0072] Compare the temperature differences of the two samples under the same conditions and analyze the heat insulation performance.

[0073] Experimental data: Summary: After the mica plate is pretreated with treatment liquid 1, its thermal barrier ability is significantly enhanced. The test results show that the sample of Example 1 significantly reduces heat loss during the temperature transfer process. Compared with Comparative Example 1, the average temperature of Example 1 is reduced by about 17 °C, and the improvement of the heat insulation effect is closely related to the functions of aerogel and silane coupling agent. The ultra-low thermal conductivity of aerogel plays a key role, while the silane coupling agent makes the treatment liquid bind more firmly to the mica paper, significantly optimizing the overall performance.

[0074] The heat insulation performance of phlogopite paper itself is limited. The sample of Comparative Example 1 formed by direct hot pressing shows a high temperature transfer rate in the experiment. This phenomenon indicates that without the dipping treatment of treatment liquid 1, the thermal management performance of mica paper depends on its natural structure, and the effect is far inferior to that of materials treated with special ratios. The experimental data further verifies how the introduction of aerogel changes the heat transfer path and reduces the speed of heat passing through the mica plate.

[0075] In addition, the temperature difference changes in the infrared thermal barrier test indicate that the proportion design of Treatment Liquid 1 is crucial. The silane coupling agent and the high-temperature resistant silicone rubber work together to form a stable heat insulation layer inside the material. In contrast, the untreated mica plate is more vulnerable to direct heat, resulting in a rapid temperature rise. The overall results of the experiment clearly highlight the core contribution of Treatment Liquid 1 to improving the heat insulation performance of the mica plate.

[0076] Experiment 2: Comparison of Heat Generation Effects in a Low-Temperature Environment Experiment Purpose: Verify the role of graphene in the low-temperature self-heating coating, and compare the heat generation effects and heat transfer performance of Example 2 and Comparative Example 2 in a low-temperature environment.

[0077] Experiment Equipment and Materials: Low-temperature constant temperature oven (temperature set at -20°C).

[0078] Thermal imager (used to record heat distribution).

[0079] Temperature sensor (records temperature changes).

[0080] PTC heating element (power 10W, voltage 12V).

[0081] Experiment Samples: Mica plates of Example 2 and Comparative Example 2 (both with dimensions of 100mm×100mm).

[0082] Experiment Steps: Set the environmental temperature of the low-temperature constant temperature oven to -20°C, and pre-cool the oven until the temperature stabilizes.

[0083] Place the mica plate prepared in Example 2 in the constant temperature oven, embed the PTC heating element, and connect the power supply (voltage 12V, power 10W).

[0084] Use the temperature sensor to measure the temperature changes on the surface and at the center of the mica plate, and record the data every 1 minute until the temperature around the battery pack reaches 25°C or the test ends.

[0085] At the same time, use the thermal imager to observe the heat distribution on the surface of the mica plate, and record and save the thermal imaging images.

[0086] After taking out the sample of Example 2, repeat steps 2 - 4 to test the mica plate sample prepared in Comparative Example 2, and record the corresponding data.

[0087] Compare the heat generation efficiency (time required to reach 25°C) and heat distribution of the two samples, and analyze the heat conduction effect of graphene.

[0088] Experiment Data: Summary: The high thermal conductivity of graphene played a core role in this experiment. Through data comparison, it can be seen that the temperature around the battery pack of the sample in Example 2 increased rapidly within a short period of time. This rapid temperature increase is due to the heat transfer characteristics of the graphene material, which quickly and evenly distributes the heat generated by the PTC heating sheet on the entire surface of the mica board. In contrast, the sample in Comparative Example 2 does not contain graphene and relies only on the thermal conductivity of the high-temperature resistant silicone rubber, resulting in significantly slower and uneven heat transfer.

[0089] Observed from the thermal imaging diagram, the heat distribution on the surface of the sample in Example 2 is more uniform. The thermal network structure formed by graphene in the low-temperature coating enables heat to quickly spread along the coating, avoiding problems such as local overheating or heat retention. In the sample of Comparative Example 2, obvious heat concentration phenomenon occurred. The thermal imaging diagram shows hot spots around the heating sheet while the temperature in the far away area is lower, which further proves the irreplaceability of graphene in achieving uniform heat transfer.

[0090] In addition, the test data shows that graphene significantly improves the heat transfer efficiency. In a low-temperature environment, the sample in Example 2 can raise the temperature around the battery pack to 25°C in only 4 minutes, while the sample in Comparative Example 2 still did not reach the target temperature after 5 minutes. This difference reflects the key advantage of the thermal conductivity of graphene, directly solving the problem of heating delay caused by uneven heat distribution or insufficient thermal conductivity in the existing technology. The experimental results further verify the remarkable effect of graphene in low-temperature thermal management materials.

[0091] Experiment 3: Coating Stability and Processing Quality Test Experimental Purpose: Verify the influence of the partition drying process on the coating stability and adhesion, and compare the differences in coating quality between Example 3 and Comparative Example 3.

[0092] Experimental Equipment and Materials: Peel tester (for testing coating adhesion).

[0093] Microscope (for observing the bubbles and cracks on the coating surface).

[0094] High and low temperature cycle test chamber (temperature range: -20°C to 80°C, cycle times 30 times).

[0095] Experimental Samples: Mica boards prepared in Example 3 and Comparative Example 3 (both with dimensions of 100mm × 100mm).

[0096] Experimental Steps: Adhesion Test: Fix the samples of Example 3 and Comparative Example 3 in the peel tester fixture respectively, and test the peel strength between the coating and the mica board substrate.

[0097] Each sample was tested 3 times, the peel force value (unit: N / m) was recorded, and the average value was taken.

[0098] Microscopic observation: Use a microscope to observe whether there are defects such as bubbles and cracks on the coating surface, and record the surface conditions of the samples.

[0099] High and low temperature cycle test: Put the samples into a high and low temperature cycle test chamber, the cycle conditions are from -20°C to 80°C, switch every 5 minutes, and last for 30 cycles.

[0100] After cycling, re-observe whether there are cracks, peeling and other phenomena on the coating surface, and record the results.

[0101] Comparative analysis: Based on the comprehensive peel strength data, microscopic observation results and the stability performance of the coating after cycling, compare the differences in the coating quality of the two groups of samples.

[0102] Experimental data: Summary: The contribution of the zoning drying process to the coating stability is particularly obvious in this experiment. The samples of Example 3 showed higher strength values in the coating adhesion test, and the average peel strength reached 56.50 N / m, which was about 30% higher than that of Comparative Example 3. This difference is due to the step-by-step curing process of zoning drying, which can effectively avoid the stress concentration problem caused by rapid drying inside the coating. The coating surface is thus denser and more uniform, which can also be clearly seen from the microscopic observation results.

[0103] Comparative Example 3 adopted a single high-temperature drying method. Although the processing time was shortened, there were many defects on the coating surface. The presence of bubbles and uneven areas indicates that during the rapid drying process, the solvents inside the coating could not be completely volatilized, resulting in local gas residues during curing. The cracks and peeling after high and low temperature cycling further confirmed the thermal stress problem in the coating processing, which is also an inherent defect of the single high-temperature drying process.

[0104] In addition, the experimental results show that the design of zoning drying effectively solves the structural stability problem of the coating during the curing process. By gradually increasing the temperature (low temperature volatilization of solvents in the first temperature zone, high temperature curing in the second temperature zone, and stabilizing the coating in the third temperature zone), the stress distribution inside the material is more uniform, avoiding cracks or delamination phenomena caused by temperature difference or too fast heating rate during the processing. This processing optimization strategy significantly improves the long-term durability and thermal cycling performance of the coating, especially suitable for the production of high-demand low-temperature thermal management materials.

[0105] Experiment 4: Relationship between Coating Thickness and Heat Transfer Efficiency Purpose of the experiment: Verify the influence of coating thickness and coating speed on the heat transfer efficiency, and compare the heat generation performance of Example 2 and Comparative Example 5 in a low-temperature environment.

[0106] Experimental equipment and materials: Low-temperature constant temperature oven (temperature set at -20°C).

[0107] PTC heating element (power 10W, voltage 12V).

[0108] Heat flow meter (measuring the heat transfer efficiency of the sample, unit: W / m 2 )

[0109] Temperature sensor (recording the temperature change inside the battery pack).

[0110] Experimental samples: Example 2 (coating thickness 0.5mm ± 0.1mm, coating speed 7m / min), Comparative Example 5 (coating thickness 0.8mm, coating speed 4m / min).

[0111] Experimental procedures: Set the ambient temperature of the low-temperature constant temperature oven to -20°C and wait for the temperature inside the oven to stabilize.

[0112] Put the samples of Example 2 and Comparative Example 5 into the low-temperature constant temperature oven respectively, and embed the PTC heating element in the middle of the sample coating.

[0113] Connect the power supply of the heating element to each sample (voltage 12V, power 10W), measure the temperature on the surface of the sample and at the center of the battery pack with a temperature sensor, and record it every 1 minute until the temperature reaches 25°C or the test ends.

[0114] Measure the heat transfer efficiency of the coating with a heat flow meter and record the heat flow data (unit: W / m 2 )

[0115] Repeat the test 3 times, record the data of each group of samples and take the average value.

[0116] Experimental data: Summary: The control of coating thickness has a significant influence on the heat transfer efficiency. The experiment shows that the coating of the sample in Example 2 is thinner and can transfer the heat generated by the PTC heating element more efficiently, and its average heat flow reaches 56.77W / m 2 , while the heat flow of the sample in Comparative Example 5 decreases to 43.47W / m 2This difference mainly stems from the enhanced thermal resistance after the increase in coating thickness, which delays the rate of heat transfer from the heating sheet to the battery pack. This further verifies the importance of precise control of coating thickness in optimizing thermal management materials.

[0117] The coating speed of the sample in Comparative Example 5 was slow and the thickness was large, resulting in a significant reduction in heat transfer efficiency. From the test results, it can be seen that the sample in Comparative Example 5 took 6.1 minutes to raise the temperature of the battery pack to 25°C, which was significantly later than 4.2 minutes in Example 2. This slow heat transfer not only affects the rapid temperature rise of the battery pack in a low-temperature environment but may also cause heat to accumulate inside the coating, increasing the risk of local overheating, while the sample in Example 2 can uniformly transfer heat quickly to the surroundings of the battery pack.

[0118] In addition, too thick a coating thickness may also have an adverse effect on the stability of the coating structure. When the coating is thick, local uneven drying may occur during the zoned drying process, resulting in a greater difference in the curing time between the inner and outer layers of the coating. This phenomenon may be manifested as unstable fluctuations in heat transfer efficiency in the heat flux test. In contrast, the coating in Example 2 shows more excellent uniformity and processing quality, and the heat distribution is more stable and uniform. The experimental results clearly show that the optimization of coating thickness and coating speed is crucial for improving heat generation efficiency and thermal management performance.

[0119] Experiment 5: Comparison of the heat insulation performance between traditional mica plates and the mica plates of the present invention Experiment purpose: By comparing Example 1 with Comparative Example 6, verify the advantages of the mica plate substrate of the present invention pretreated with treatment liquid 1 in heat insulation performance, and reveal the deficiencies of traditional mica plates in heat insulation ability.

[0120] Experiment equipment and materials: Constant temperature oven (set the internal temperature to 100°C).

[0121] Thermocouple temperature sensor (accuracy ±0.1°C).

[0122] Experiment samples: The mica plate substrate prepared in Example 1 (pretreated with treatment liquid 1), and the traditional mica plate in Comparative Example 6 (not pretreated with treatment liquid 1).

[0123] Test bracket (used to fix the sample and record the temperature above the sample surface).

[0124] Experiment steps: Set the constant temperature oven to 100°C and wait for the temperature inside the oven to reach stability.

[0125] Cover the mica plate sample prepared in Example 1 (with dimensions of 200 mm × 200 mm) on the opening at the top of the constant temperature oven, fix the test bracket, and place the sensor 20 mm away from the sample surface to record the temperature change under the influence of the heat passing through the mica plate.

[0126] Start the experiment, record the temperature data of the sensor every 10 seconds, and continuously measure for 2 minutes. Repeat the experiment 3 times, record all the data and take the average value.

[0127] Follow the same steps to test the sample of Comparative Example 6 and record the corresponding temperature data.

[0128] Compare the temperature differences between the two groups of samples under the same conditions and analyze their heat insulation performance.

[0129] Experimental data: Summary: The heat insulation ability of the traditional mica plate showed obvious deficiencies in this experiment. During the experiment of the sample of Comparative Example 6, heat was more likely to be transferred to the surface through the material, resulting in its average temperature being about 14 °C higher than that of Example 1. This difference shows that the mica plate without being impregnated with Treatment Liquid 1 relies only on its natural structure for heat insulation, and this structure is inadequate when facing a continuous heat source. In contrast, the sample of Example 1 showed a more excellent heat barrier effect, which is closely related to the introduction of aerogel in Treatment Liquid 1. The microporous structure of the aerogel effectively reduced the heat conduction rate by reducing the heat transfer path.

[0130] In the later stage of the experiment, the temperature rise rate of the sample of Example 1 slowed down significantly, while that of Comparative Example 6 continued to rise. This further proves the role of the silane coupling agent in the interfacial bonding of the material, which enhanced the adhesion between Treatment Liquid 1 and the mica paper, making the thermal resistance performance of the material more stable and uniform. Without this interfacial strengthening, the untreated mica plate allowed heat to penetrate more directly into the material interior, unable to form an effective heat barrier layer.

[0131] In addition, this experiment reveals the key to the heat insulation performance of mica plates in high-temperature environments. The high-temperature resistant silicone rubber in Example 1 has an obvious inhibitory effect on heat transfer. It not only improves the high-temperature resistance of the material but also optimizes the overall heat insulation performance in combination with the aerogel. The design of this composite material system meets the heat insulation requirements while maintaining high mechanical strength and processing stability, laying a solid foundation for the application of mica plates in the new energy field.

[0132] Experiment 6: Comparison of the insulation performance of mica plates in a high-humidity environment Experimental purpose: Compare the insulation performance of Example 3 (mica plate pretreated with Treatment Liquid 2) and Comparative Example 7 (mica plate without Treatment Liquid 2) in a high-humidity environment to verify the effect of Treatment Liquid 2 on improving the moisture-resistant insulation performance of mica plates.

[0133] Experimental equipment and materials: High-humidity environment chamber (humidity set at 90%, temperature 25°C).

[0134] Insulation resistance tester (range 1 GΩ to 100 GΩ).

[0135] Experimental samples: Mica plates of Example 3 (pretreated with Treatment Liquid 2) and mica plates of Comparative Example 7 (untreated).

[0136] High-voltage power supply (500 V).

[0137] Experimental steps: Place the experimental samples (size 50 mm × 50 mm) into the high-humidity environment chamber respectively, maintain a humidity of 90% and a temperature of 25°C, and the pretreatment time is 24 hours to simulate an extreme humidity environment.

[0138] Take out the samples, immediately fix them on the insulation resistance tester, connect to the high-voltage power supply (500 V), and start measuring the insulation resistance of the samples.

[0139] Record the insulation resistance value every 5 seconds and continuously measure for 1 minute. Repeat the test 3 times, record all data and take the average value.

[0140] Compare the differences in insulation performance between Example 3 and Comparative Example 7 in a high-humidity environment.

[0141] Observe the surface changes of the samples and record possible bubbling, peeling or other defects.

[0142] Experimental data: Summary: Treatment Liquid 2 has a significant improvement effect on the insulation performance of mica plates in a high-humidity environment. The samples of Example 3 showed a higher insulation resistance in a high-humidity environment, with an average value reaching 72.63 GΩ, while that of Comparative Example 7 was only 36.90 GΩ, and the performance was almost doubled. This difference comes from the synergistic effect of the silane coupling agent and the modified siloxane in Treatment Liquid 2, which form a dense hydrophobic coating on the surface of the mica paper, greatly reducing the possibility of moisture entering the material interior, thus significantly improving the insulation performance. The samples of Comparative Example 7 showed obvious moisture absorption in a high-humidity environment due to the lack of hydrophobic coating protection, resulting in a rapid decrease in insulation resistance.

[0143] Further surface observations revealed that the sample of Example 3 maintained a complete and uniform coating after testing, without obvious bubbling or peeling. In contrast, the sample of Comparative Example 7 showed varying degrees of bubbling and edge delamination after high-humidity treatment, which may be related to its relatively high hygroscopic structure. After moisture entered the material, the interfacial adhesion strength decreased, resulting in the loss of surface stability of the material. This phenomenon clearly reflects the differences in material interface bonding and environmental adaptability.

[0144] In addition, the decreasing trend of the insulation resistance during the test further demonstrated the contribution of Treatment Liquid 2 to the long-term stability of the mica plate. The insulation resistance of the sample of Example 3 remained at 68.8 GΩ after 60 seconds, with a relatively small decrease, while that of Comparative Example 7 decreased significantly to 28.9 GΩ. This indicates that Treatment Liquid 2 not only enhanced the short-term moisture resistance of the mica plate but also extended its insulation stability in a high-humidity environment. This significant improvement in performance provides higher safety guarantees for the application of mica plates in humid and complex working conditions.

[0145] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A new energy power battery low temperature heating mica board, characterized in that: Includes the following materials: The mica board substrate is made of phlogopite paper as the main raw material and is treated with a treatment liquid 1 prepared from high temperature resistant organic silica gel, aerogel and silane coupling agent; A low-temperature self-heating coating, wherein a treatment liquid 2 composed of high-temperature resistant organic silica gel and graphene as main components is evenly coated on the surface of the mica substrate; The PTC composite heating sheet is embedded between the low-temperature self-heating coating and the mica board substrate, and is used to realize the self-heating function of the board in a low-temperature environment.

2. A new energy power battery low temperature heating mica board according to claim 1, characterized in that: The treatment solution 1 includes the following components: High temperature resistant organic silicone: 70%~90%; Aerogel: 25% to 45%; Silane coupling agent: 8%~10%.

3. A new energy power battery low temperature heating mica board according to claim 1, characterized in that: The treatment solution 2 includes the following components: High temperature resistant organic silicone: 20%~30%; Graphene: 15%~25%.

4. A method for preparing a low-temperature heating mica plate for a new energy power battery, according to a low-temperature heating mica plate for a new energy power battery according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Prepare treatment liquid 1: mix high temperature resistant organic silica gel, aerogel, kaolin powder and silane coupling agent in proportion in a blender for 60 minutes to form a uniform treatment liquid 1; S2, mica paper pretreatment: the treatment solution 1 is evenly coated on the surface of the phlogopite mica paper by dipping; S3, hot pressing of mica board: placing the pretreated mica paper in a hot press and hot pressing for more than 30 minutes to form a mica board substrate; S4, preparing treatment liquid 2: putting high temperature resistant organic silica gel and graphene into a blender according to a certain proportion and mixing for 60 minutes to form a uniform treatment liquid 2; S5, coating low-temperature self-heating coating: using a sandwich coating process to evenly coat the treatment liquid 2 on the surface of the mica substrate, and embedding the PTC composite heating sheet; S6. Drying: Use zone drying method and set three temperature zones with different temperature ranges for drying.

5. The method for preparing a low-temperature heating mica board for a new energy power battery according to claim 4, characterized in that: In the step S1, the stirring speed of the stirrer is ≥500 r / min.

6. The method for preparing a low-temperature heating mica board for a new energy power battery according to claim 4, characterized in that: In the step S2, the dipping speed of the dipping method is controlled at 3m / min to 5m / min.

7. The method for preparing a low-temperature heating mica board for a new energy power battery according to claim 4, characterized in that: In the step S3, the hot pressing temperature of the hot pressing machine is 180° C. to 260° C., and the hot pressing pressure is 1.9 MPa to 2.6 MPa.

8. The method for preparing a low-temperature heating mica board for a new energy power battery according to claim 4, characterized in that: In the step S4, the stirring speed of the stirrer is ≥500 r / min.

9. The method for preparing a low-temperature heating mica board for a new energy power battery according to claim 4, characterized in that: In the step S5, the thickness of the gap coating is 0.5 mm ± 0.1 mm, and the coating speed is 6 m / min to 8 m / min.

10. The method for preparing a low-temperature heating mica board for a new energy power battery according to claim 4, characterized in that: In the step S6, the temperature range includes: The first temperature zone: 80℃~100℃; The second temperature zone: 130℃~150℃; The third temperature zone: 100℃~110℃.

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