An integrated component for temperature control and early warning of new energy vehicle battery packs

Abstract

This invention discloses an integrated component for temperature control and early warning of a new energy vehicle battery pack. Multiple first self-temperature-regulating composite materials are present, each wrapping around each battery cell inside the new energy vehicle battery pack. These multiple first self-temperature-regulating composite materials are connected in parallel to the batteries. A flexible high thermal conductivity film is tightly connected to the first self-temperature-regulating composite materials on each battery cell inside the new energy vehicle battery pack. One end of the flexible high thermal conductivity film is also connected to a second self-temperature-regulating composite material, which is connected to a display via a smart switch. The other end of the flexible high thermal conductivity film wraps around part or all of the heat-conducting pipes connected in series with the condenser, pump, and water tank. The heat-conducting film of this invention can promptly and evenly transfer heat from inside the battery to the circulating water pipes. For the heat-conducting film connecting the early warning system in the middle of the battery pack, a portion of the heat is transferred to the early warning self-temperature-regulating composite material for early warning purposes, and the remainder is transferred to the circulating water pipes.

Description

Technical Field

[0001] This invention relates to the field of temperature control and early warning technology for new energy vehicle batteries, specifically to an integrated component for temperature control and early warning of new energy vehicle battery packs. Background Technology

[0002] With the increasing emphasis on environmental protection and the deepening implementation of the concept of sustainable development, the new energy field is developing rapidly. Common examples include new energy vehicles, which use electricity instead of fuel to power cars, reducing emissions and contributing to long-term environmental protection. However, new energy vehicle technology is not yet fully mature. Taking car batteries as an example, effectively controlling battery temperature is a major concern, as battery charging and discharging capabilities and safety are significantly affected by temperature. Batteries can only function normally within a range of 15–42°C. Temperatures that are too low can cause batteries to malfunction, while excessively high temperatures not only accelerate battery aging and shorten their lifespan but may also lead to fires, explosions, and other accidents, seriously threatening the safety of passengers and causing loss of life and property. The heat generated by the battery pack dissipates slowly under natural, untreated conditions. Furthermore, to provide vehicles with higher power and range, battery packs are becoming increasingly larger, resulting in a smaller relative surface area. This leads to a series of battery thermal management issues, further accelerating battery performance degradation and shortening battery lifespan.

[0003] To ensure that batteries can operate in a suitable temperature environment, the most commonly used thermal management systems are air thermal management, liquid thermal management, and PCM thermal management. Air thermal management uses radiators or independent coolers to dissipate heat from the battery, while electric heaters heat the battery. Liquid thermal management lowers or raises the battery temperature through water circulation. PCM thermal management uses phase change materials (PCM) to absorb a large amount of latent heat in the battery, thereby maintaining a stable battery temperature. In existing electric vehicle battery thermal management technologies, there are problems such as poor temperature uniformity and low thermal management efficiency (Xiao Feng, Yang Bing, Zhang Yurong. Research on temperature control methods of electric vehicle battery thermal management system [J]. Internal Combustion Engine and Parts, 2021(05):198-199.). Because high thermal conductivity materials can dissipate heat in a timely manner, installing them around the outside of the battery can solve the problems of poor temperature uniformity and low efficiency to a certain extent. In addition, self-temperature-regulating composite materials are lightweight and flexible, and installing them around the outside of the battery can also achieve uniform heating.

[0004] With the continuous development of power detection technology, battery detection and early warning products for electric vehicles have gradually become mature. However, most early warning systems on the market at present simply measure the battery voltage. When the internal ohm value of the battery is large, the detected battery voltage value is not accurate enough. Therefore, how to achieve automatic, intelligent and accurate early warning for electric vehicles is an urgent problem to be solved.

[0005] Chinese invention patent 201410720277.1 discloses a liquid-cooled battery system for new energy vehicles and its temperature control method. The liquid-cooled battery system includes a battery system and a temperature control system. The battery system includes a battery pack and a battery management system installed therein. The temperature control system includes a high-pressure liquid heater, an electric three-way valve, a liquid-liquid heat exchanger, and a drive pump connected in series with the battery system; a battery radiator disposed between the electric three-way valve and the drive pump; and an electric air conditioning compressor, an air conditioning radiator, and a solenoid valve connected in series with the liquid-liquid heat exchanger. This technology lacks self-temperature control and, due to the loose connection between the battery and the cooling system, cannot guarantee the implementation of a warning function. Summary of the Invention

[0006] The purpose of this invention is to provide an integrated component for temperature control and early warning of new energy vehicle battery packs, which solves the problem that existing battery temperature control and early warning systems are not accurate enough.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An integrated component for temperature control and early warning of a new energy vehicle battery pack includes a first self-regulating temperature composite material, a second self-regulating temperature composite material, a smart switch, a flexible high thermal conductivity film, a condenser, a pump, a display, and a water tank. Multiple first self-regulating temperature composite materials are present, each wrapping around each battery cell inside the new energy vehicle battery pack. These multiple first self-regulating temperature composite materials are connected in parallel to the batteries. The flexible high thermal conductivity film is tightly connected to the first self-regulating temperature composite materials on each battery cell inside the new energy vehicle battery pack. One end of the flexible high thermal conductivity film is also connected to the second self-regulating temperature composite material, which is connected to the display via the smart switch. The other end of the flexible high thermal conductivity film wraps around part or all of the heat-conducting pipes connected in series by the condenser, pump, and water tank. The first self-regulating temperature composite material has a Curie temperature of 30℃-40℃; the second self-regulating temperature composite material has a Curie temperature of 60-80℃; and the flexible high thermal conductivity film has a thermal conductivity of 775-1045 W / (m K).

[0009] To further achieve the purpose of the invention, preferably, the thickness of the flexible high thermal conductivity film is 5-15 mm.

[0010] Preferably, the internal valve body of the intelligent switch is a normally open single valve structure.

[0011] Preferably, the method for preparing the flexible high thermal conductivity film includes the following steps:

[0012] (1) Pretreatment: Wash the graphite powder until it is neutral, filter it to obtain a solid, and dry it;

[0013] (2) Oxidation: Add KMnO4 to the mixture of graphite powder and concentrated sulfuric acid obtained from pretreatment, control the temperature to be below 5-10℃, after adding, adjust the temperature to 25-35℃ and maintain for 20-30 min, then dilute with deionized water, then adjust the temperature to 75-85℃, stir magnetically for 10-20 min, and add deionized water and H2O2.

[0014] (3) Purification: Let the mixture stand until it separates into layers, pour off the supernatant, add dilute hydrochloric acid to the turbid liquid and let it stand to separate into layers again. Repeat this washing process. Then add deionized water to the turbid liquid, stir evenly and centrifuge. Then wash with deionized water. Add water to the obtained solid GO, stir and sonicate for 2-3 hours to obtain GO aqueous solution.

[0015] (4) Preparation of GO dispersion: The GO aqueous solution was evenly distributed in the pretreated dialysis bag and purified by dialysis in deionized water for 5-10 days. The solution was tested with pH paper and found to be neutral. No white precipitate was generated when tested with BaCl2. The GO dispersion was thus prepared.

[0016] (5) Preparation of flexible high thermal conductivity film: Pour the GO dispersion into the evaporation tank and treat it in the atmosphere of 50-70℃ in the drying oven for 6-8 hours to obtain graphene oxide film; put the graphene oxide film into the hot press mold, move it to the high temperature tube furnace under the protection of argon atmosphere at 600-800℃, cool it to room temperature under the argon atmosphere, and take it out to obtain flexible high thermal conductivity film.

[0017] Preferably, the pretreatment in step (1) involves washing the graphite powder sequentially with dilute HCl and deionized water until neutral, filtering to obtain a solid, and then drying it in a vacuum drying oven until it is completely dry.

[0018] In step (2), the mass ratio of graphite powder to concentrated sulfuric acid is 1:1 to 1:2; the amount of KMnO4 used is 2 to 3 times the mass of the graphite powder obtained from the pretreatment.

[0019] The pretreatment of the dialysis bag involves sequentially rinsing the dialysis bag with a mixed solution of deionized water, EDTA, and NaHCO3, boiling the mixed solution, and then rinsing it multiple times with deionized water.

[0020] Preferably, the first self-temperature-controlled composite material is prepared by the following steps:

[0021] 1) Add conductive particles to a mixed solution of organic solvents, add coupling agent after mixing, sonicate for 30-45 min, then mechanically stir at 1000-1500 r / min for 20-30 min, add foaming agent and foaming aid, and mechanically stir at 1000-1500 r / min for 30-45 min to obtain a mixed solution.

[0022] 2) After mixing the silicone rubber and the diluent, mechanically stir at 3000-4000 r / min for 30-45 min to obtain a silicone rubber mixture;

[0023] 3) Mix the obtained mixed solution with the silicone rubber mixture, add antioxidants, ultraviolet absorbers and other additives, and mechanically stir at 3000-4000 r / min for 1-1.5 h, then add the catalyst and mix and stir for 5-10 min until uniform;

[0024] 4) Coat the mixture obtained in step 3) onto the polyimide film etched with copper electrode plates, dry, and cool to room temperature;

[0025] The conductive particles are carbon black, carbon nanotubes, nickel powder, or aluminum silver powder; the particle size of carbon black is 20-90 nm; the outer diameter of carbon nanotubes is 8-15 nm, the inner diameter is 3-5 nm, and the length is 3-12 μm; the particle size of nickel powder is 2-2.5 μm; and the particle size of aluminum silver powder is 10-15 μm.

[0026] The foaming agent is azodicarbonamide or p-toluenesulfonyl hydrazine; the foaming aid is zinc oxide; the crosslinking agent is tetraethyl orthosilicate; and the catalyst is octyltin or dibutyltin dilaurate.

[0027] Preferably, the raw material formulation of the first self-regulating temperature composite material, by mass parts, comprises: 100 parts of silicone rubber matrix, 15-30 parts of conductive particles, 3-5 parts of coupling agent, 8-20 parts of foaming agent, 8-20 parts of foaming aid, 10-80 parts of organic solvent, 2-8 parts of diluent, 1-10 parts of crosslinking agent, 0.5-5 parts of catalyst, 0.3-1 part of antioxidant, 0.2-0.5 parts of ultraviolet absorber, and 0.2-0.5 parts of other additives.

[0028] Preferably, the silicone rubber is No. 107 silicone rubber with a viscosity of one or more of 750cSt, 1000cSt, 2000cSt, 5000cSt, and 10000cSt; the coupling agent is one of KH-550 and KH-570.

[0029] The organic solvent is one or more selected from n-hexane, ethanol, and xylene;

[0030] The diluent is one or more of dimethyl silicone oil and n-hexane;

[0031] The antioxidant mentioned is one or more of antioxidant DNP and antioxidant BHT;

[0032] The ultraviolet absorber mentioned is UV-531;

[0033] The other additives mentioned are one or more of polyethylene glycol and glycol.

[0034] Preferably, the second self-temperature-controlled composite material is prepared by the following steps:

[0035] 1) Add conductive particles to a mixed solution of organic solvents, add coupling agent after mixing, sonicate for 30-45 min, then mechanically stir at 1000-1500 r / min for 20-30 min, add foaming agent and foaming aid, and mechanically stir at 1000-1500 r / min for 30-45 min to obtain a mixed solution.

[0036] 2) After mixing the silicone rubber with the diluent, mechanically stir at 3000-4000 r / min for 30-45 min to obtain a silicone rubber mixture;

[0037] 3) Mix the mixed solution with the silicone rubber mixture, add antioxidants, ultraviolet absorbers and other additives, and mechanically stir at 3000-4000 r / min for 1-1.5 h, then add the catalyst and mix for 5-10 min until uniform;

[0038] 4) Coat the mixture obtained in step 3) onto a polyimide film etched with copper electrode plates, dry it, and cool it to room temperature;

[0039] The conductive particles are carbon black, carbon nanotubes, nickel powder, or aluminum silver powder; wherein the carbon black has a particle size of 20-90 nm; the carbon nanotubes have an outer diameter of 8-15 nm, an inner diameter of 3-5 nm, and a length of 3-12 μm; the nickel powder has a particle size of 2-2.5 μm; and the aluminum silver powder has a particle size of 10-15 μm.

[0040] The foaming agent is azodicarbonamide or p-toluenesulfonyl hydrazine; the foaming aid is zinc oxide;

[0041] The crosslinking agent is tetraethyl orthosilicate; the catalyst is octyltin or dibutyltin dilaurate.

[0042] Preferably, the second self-temperature-regulating composite material raw material formulation, by mass parts, comprises: 100 parts silicone rubber, 10-20 parts conductive particles, 2-5 parts coupling agent, 3-10 parts foaming agent, 3-10 parts foaming aid, 10-70 parts organic solvent, 2-6 parts diluent, 1-10 parts crosslinking agent, 0.5-5 parts catalyst, 0.2-1 part antioxidant, 0.2-0.5 parts ultraviolet absorber, and 0.1-0.5 parts other additives.

[0043] Preferably, the silicone rubber is No. 107 silicone rubber with a viscosity of one or more of 750cSt, 1000cSt, 2000cSt, 5000cSt, and 10000cSt.

[0044] The coupling agent is one of KH-550 and KH-570;

[0045] The organic solvent is one or more selected from n-hexane, ethanol, and xylene;

[0046] The diluent is one or more of dimethyl silicone oil and n-hexane;

[0047] The antioxidant mentioned is one or more of antioxidant DNP and antioxidant BHT;

[0048] The ultraviolet absorber is UV-531; the other additives are one or more of polyethylene glycol and glycol.

[0049] Compared with the prior art, the present invention has the following technical effects and advantages:

[0050] 1) This invention changes the conventional battery heat dissipation method from taking heat dissipation measures on the outside of the battery pack to installing a flexible high thermal conductivity film around the battery pack and on the top inside the battery pack, so as to avoid local heat accumulation in the battery; at the same time, the flexible high thermal conductivity film of this invention is very thin and has a high thermal conductivity, so as to meet the heat transfer requirements without seriously affecting the original weight and size of the battery pack.

[0051] 2) The composite material with added foaming agent in this invention can form a uniform, dense, and closed sponge-like bubble structure inside. This bubble structure has a large shrinkage rate and large deformation, allowing it to expand and deform as the composite material's temperature rises. This increases the overall thermal expansion of the material, making temperature control easier. The matrix does not undergo a phase change during the entire process, making it more suitable for applications requiring high material safety, such as automotive batteries. Furthermore, because the matrix material is rubber, which constitutes the majority of the prepared material, the overall flexibility of the material is comparable to that of rubber. In addition, the self-regulating temperature of the conductive composite material can be adjusted by changing the amount of foaming agent.

[0052] 3) The conductivity mechanism of the self-temperature-regulating composite material used in this invention is mainly based on thermal expansion. When the temperature of the composite material is low, the conductive matrix and conductive particles form a three-dimensional network of conductive particles, resulting in low resistance. As the temperature increases, the coefficient of thermal expansion of the conductive matrix is ​​greater than that of the conductive particles, leading to greater thermal expansion of the matrix and a relatively larger distance between the conductive particles. This causes the conductive network to be destroyed, and the resistance gradually increases. When the conductive network is destroyed to a certain extent, the conductive particles are insufficient to form a conductive path, and the resistance increases to a certain value, resulting in an open circuit, thereby achieving the purpose of self-temperature regulation.

[0053] 4) This invention uses a self-regulating temperature-controlled composite material to wrap around the battery pack for insulation and heating. This material does not undergo a phase change during heat generation, making it safer. Simultaneously, a flexible, high-thermal-conductivity film is installed around the battery pack and on top to dissipate heat. This invention places an independent self-regulating temperature-controlled composite material on the outermost layer of the battery pack, utilizing its material property of increasing resistance with temperature to provide an early warning. Utilizing the inherent properties of the self-regulating temperature-controlled composite material, the material resistance increases sharply when the temperature reaches the Curie temperature. Therefore, when the resistance is below the set resistance, the switch is in the open state; when the resistance is above the set resistance, the switch closes, triggering an early warning.

[0054] 5) When the ambient temperature is low, an electric current is applied to one end of the self-regulating temperature composite material to maintain a constant temperature and thus keep the battery pack warm. When the vehicle generates too much heat and the temperature becomes too high during operation, the heat-conducting film promptly and evenly transfers the heat inside the battery to the circulating water pipe. For the heat-conducting film connecting the warning system in the middle of the battery pack, a portion of the heat is transferred to the warning self-regulating temperature composite material for warning purposes, and the remainder is transferred to the circulating water pipe.

[0055] 6) This invention features a simple structure, safe properties, uniform heat dissipation, and uniform heat preservation and heating. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure of an integrated component for temperature control and early warning of a new energy vehicle battery pack according to the present invention.

[0057] Figure 2 The temperature rise curves of the first self-temperature-controlled composite material in Example 1 when 9V, 20V and 30V voltages are applied.

[0058] Figure 3 The temperature rise curves of the second self-temperature-controlled composite material in Example 1 when 9V, 20V and 30V voltages are applied.

[0059] Figure 4 A bar chart comparing the thermal conductivity of copper and the three groups of flexible high thermal conductivity films from Examples 1-3.

[0060] Figure 5aTo simulate the temperature rise of a battery under natural conditions using COMSOL.

[0061] Figure 5b To simulate the temperature rise of the battery in Example 1 using COMSOL.

[0062] Figure 6 The temperature rise curves of the first self-temperature-controlled composite material in Example 2 when 9V, 20V and 30V voltages are applied.

[0063] Figure 7 The temperature rise curves of the second self-temperature-controlled composite material in Example 2 when 9V, 20V and 30V voltages are applied.

[0064] Figure 8 To simulate the temperature rise of the battery in Example 2 using COMSOL.

[0065] Figure 9 The temperature rise curves of the first self-temperature-controlled composite material in Example 3 when 9V, 20V and 30V voltages are applied.

[0066] Figure 10 The temperature rise curves of the second self-temperature-controlled composite material in Example 3 when 9V, 20V and 30V voltages are applied.

[0067] Figure 11 To simulate the temperature rise of the battery in Example 3 using COMSOL. Detailed Implementation

[0068] To make the problems solved, the solutions adopted, and the effects achieved by this invention clearer, the invention will be further described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0069] like Figure 1As shown, an integrated component for temperature control and early warning of a new energy vehicle battery pack includes a first self-regulating temperature composite material 1, a second self-regulating temperature composite material 2, an intelligent switch 3, a flexible high thermal conductivity film 4, a condenser 5, a pump 6, a display 7, and a water tank 8. Multiple first self-regulating temperature composite materials 1 are present, each wrapping around each battery cell inside the new energy vehicle battery pack. Multiple first self-regulating temperature composite materials 1 are connected in parallel to the batteries. The flexible high thermal conductivity film 4 is tightly connected to the first self-regulating temperature composite material 1 on each battery cell inside the new energy vehicle battery pack. One end of the flexible high thermal conductivity film 4 is also connected to the second self-regulating temperature composite material 2, which is connected to the display 7 via the intelligent switch 3. The other end of the flexible high thermal conductivity film 4 wraps around part or all of the heat-conducting pipes connected in series by the condenser 5, pump 6, and water tank 8. The first self-regulating temperature composite material 1 is a self-regulating temperature composite material with a Curie temperature of 30℃-40℃; the second self-regulating temperature composite material 2 is a self-regulating temperature composite material with a Curie temperature of 60-80℃.

[0070] Preferably, the flexible high thermal conductivity film 4 is a flexible high thermal conductivity film with a thermal conductivity of 775-1045 W / (m K);

[0071] Preferably, the internal valve body of the intelligent switch 3 is a normally open single valve structure.

[0072] Preferably, the thickness of the flexible high thermal conductivity film 4 is 5-15 mm.

[0073] Preferably, the first self-temperature-controlled composite material is prepared by the following method:

[0074] 1) Add conductive particles to a mixed solution of organic solvents, add coupling agent after mixing, sonicate for 30-45 min, then mechanically stir at 1000-1500 r / min for 20-30 min, add foaming agent and foaming aid, and mechanically stir at 1000-1500 r / min for 30-45 min to obtain a mixed solution.

[0075] 2) After mixing the silicone rubber and the diluent, mechanically stir at 3000-4000 r / min for 30-45 min to obtain a silicone rubber mixture;

[0076] 3) Add antioxidants, ultraviolet absorbers and other additives to the obtained mixed solution and silicone rubber mixture, and mechanically stir at 3000-4000 r / min for 1-1.5 h. Then add the catalyst and mix and stir for 5-10 min until uniform.

[0077] 4) Coat the mixture obtained in step 3) onto the polyimide film etched with copper electrode plates, dry it, and cool it to room temperature.

[0078] The first self-regulating temperature composite material, by weight, comprises: 100 parts silicone rubber matrix, 15-30 parts conductive particles, 3-5 parts coupling agent, 8-20 parts foaming agent, 8-20 parts foaming aid, 10-80 parts organic solvent, 2-8 parts diluent, 1-10 parts crosslinking agent, 0.5-5 parts catalyst, 0.3-1 part antioxidant, 0.2-0.5 parts ultraviolet absorber, and 0.2-0.5 parts other additives; wherein the silicone rubber is No. 107 silicone rubber with a viscosity of one or more of 750cSt, 1000cSt, 2000cSt, 5000cSt, and 10000cSt. When using silicone rubber of various viscosities, the proportion is determined according to actual requirements; the conductive particles are carbon black (20-9... The following components are used: 0nm or carbon nanotubes (outer diameter 8-15nm, inner diameter 3-5nm, length 3-12μm), nickel powder (2-2.5μm) or aluminum silver powder (10-15μm); coupling agent is one of KH-550 and KH-570; foaming agent is azodicarbonamide or p-toluenesulfonyl hydrazine; foaming aid is zinc oxide; organic solvent is one or more of n-hexane, ethanol, and xylene; diluent is one or more of dimethyl silicone oil and n-hexane; crosslinking agent is tetraethyl orthosilicate; catalyst is octyltin or dibutyltin dilaurate; antioxidant is one or more of antioxidant DNP and antioxidant BHT; ultraviolet absorber is UV-531; other additives are one or more of polyethylene glycol and glycol.

[0079] The second self-temperature-controlled composite material is prepared through the following steps:

[0080] 1) Add conductive particles to a mixed solution of organic solvents, add coupling agent after mixing, sonicate for 30-45 min, then mechanically stir at 1000-1500 r / min for 20-30 min, add foaming agent and foaming aid, and mechanically stir at 1000-1500 r / min for 30-45 min to obtain a mixed solution.

[0081] 2) After mixing the silicone rubber with the diluent, mechanically stir at 3000-4000 r / min for 30-45 min to obtain a silicone rubber mixture;

[0082] 3) Mix the mixed solution with the silicone rubber mixture, add antioxidants, ultraviolet absorbers and other additives, and mechanically stir at 3000-4000 r / min for 1-1.5 h, then add the catalyst and mix for 5-10 min until uniform;

[0083] 4) Apply the mixture obtained in step 3) onto a polyimide film etched with copper electrode plates, dry it, and cool it to room temperature.

[0084] The second self-regulating temperature composite material, by mass parts, comprises: 100 parts silicone rubber matrix, 10-20 parts conductive particles, 2-5 parts coupling agent, 3-10 parts foaming agent, 3-10 parts foaming aid, 10-70 parts organic solvent, 2-6 parts diluent, 1-10 parts crosslinking agent, 0.5-5 parts catalyst, 0.2-1 part antioxidant, 0.2-0.5 parts ultraviolet absorber, and 0.1-0.5 parts other additives; wherein the silicone rubber is No. 107 silicone rubber with a viscosity of one or more of 750 cSt, 1000 cSt, 2000 cSt, 5000 cSt, and 10000 cSt. When using silicone rubber of various viscosities, the proportion is determined according to actual requirements; the conductive particles are carbon black (20-9... The following components are used: 0nm or carbon nanotubes (outer diameter 8-15nm, inner diameter 3-5nm, length 3-12μm), nickel powder (2-2.5μm) or aluminum silver powder (10-15μm); coupling agent is one of KH-550 and KH-570; foaming agent is azodicarbonamide or p-toluenesulfonyl hydrazine; foaming aid is zinc oxide; organic solvent is one or more of n-hexane, ethanol, and xylene; diluent is one or more of dimethyl silicone oil and n-hexane; crosslinking agent is tetraethyl orthosilicate; catalyst is octyltin or dibutyltin dilaurate; antioxidant is one or more of antioxidant DNP and antioxidant BHT; ultraviolet absorber is UV-531; other additives are one or more of polyethylene glycol and glycol.

[0085] The preparation method of flexible high thermal conductivity film includes the following steps:

[0086] 1) Pretreatment: The graphite powder was washed with dilute HCl and deionized water in sequence until neutral, filtered to obtain a solid, and then dried in a vacuum drying oven for several hours until it was completely dry.

[0087] 2) Oxidation: Slowly add 2 to 3 times the mass of the pretreated graphite powder to the mixture of pretreated graphite powder and concentrated sulfuric acid (1:1 to 1:2, mass ratio), keeping the temperature below 5 to 10°C. After the addition is complete, adjust the temperature to 25 to 35°C and maintain it for 20 to 30 minutes. Then dilute with deionized water, adjust the temperature to 75 to 85°C, and stir magnetically for 10 to 20 minutes. Add deionized water and H2O2 to react and remove excess KMnO4.

[0088] 3) Purification: Let the mixture stand until it separates into layers, discard the supernatant, add dilute hydrochloric acid to the lower turbid liquid and let it stand to separate into layers again. Repeat this washing process. Then add deionized water to the lower turbid liquid, stir evenly and centrifuge. Then wash with deionized water. Add water to the obtained solid GO, stir and sonicate for 2-3 hours to obtain GO dispersion.

[0089] 4) Dialysis bag pretreatment: The dialysis bag is sequentially rinsed with a mixed solution of deionized water, EDTA, and NaHCO3, the mixed solution is boiled, and then rinsed several times with deionized water and set aside for later use.

[0090] 5) Preparation of GO dispersion: The GO dispersion obtained above was evenly distributed in dialysis bags and purified by dialysis in deionized water for 5-10 days. The solution was tested with pH paper and found to be neutral. No white precipitate was formed when tested with BaCl2, indicating that the impurity ions in the solution were basically removed, and the GO dispersion was obtained.

[0091] 6) Preparation of flexible high thermal conductivity film: Pour the GO dispersion into the evaporation tank and treat it in the atmosphere of 50-70℃ in the drying oven for 6-8 hours to obtain graphene oxide film; put the graphene oxide film into the hot press mold, transfer it to the high temperature tube furnace under the protection of argon atmosphere at 600-800℃, cool it to room temperature under the argon atmosphere and take it out to obtain flexible high thermal conductivity film.

[0092] When the resistance of the second self-temperature-regulating composite material 2 is lower than the set value, the valve body of the intelligent switch 3 is normally open; when the resistance of the second self-temperature-regulating composite material 2 is higher than the set value, the valve body of the intelligent switch 3 gradually closes until it is completely closed, thereby triggering the warning.

[0093] The flexible high thermal conductivity film 4 is used to dissipate excess heat generated by the battery, preventing localized overheating. Because the thermal conductivity film is only 5-15mm thick and lightweight, its impact on the spacing between battery packs and the overall size of the automotive battery pack is negligible. It can be fixed using methods such as thin-film adhesive coating, mechanical pressing, or riveting. The flexible high thermal conductivity film 4 is tightly installed in contact with the first self-regulating temperature composite material 1, extending its lower end to the circulating water pipe or the early warning self-regulating temperature composite material, with the thermal conductivity film area distributed according to heat distribution.

[0094] The condenser 5 transfers the flexible, high thermal conductivity film 4 to the water cooling in the heat-conducting pipe. The condenser is located in the middle of the pipe to cool the water in the pipe, increase the temperature difference, and accelerate heat conduction.

[0095] Without external interference, water flows in the pipes using potential energy. However, the power provided by the car alone may not be enough to achieve rapid water circulation and may affect heat transfer. Therefore, a pump is added to the process and installed in the middle of the circulating water pipe, adjacent to the car's own water tank. Installing it in this position can provide greater circulation power for the water and promote heat transfer.

[0096] When the vehicle starts and detects that the battery temperature is below 15°C, the heating circuit is closed, and the first self-temperature-controlled composite material 1 begins to heat the battery. At this time, the circulating water circuit is disconnected.

[0097] If the battery temperature is detected to be higher than 42°C during operation, heating will stop. Considering that the battery will continue to generate heat during operation, the heat dissipation intensity needs to be increased. At this time, the circulating water circuit will start running.

[0098] Example 1:

[0099] 1. Preparation of the first self-temperature-controlled composite material (Curie temperature point is 30℃)

[0100] (1) Add 12 parts of carbon black (particle size 80-90nm), 8 parts of carbon nanotubes (outer diameter 11-15nm, inner diameter 3-5nm, length 3-6μm) and 5 parts of aluminum silver powder (particle size 13-15μm) to a 60-part mixed solution of hexane and ethanol in a ratio of 4:1. After mixing, add 5 parts of coupling agent KH-550, sonicate for 40min, then mechanically stir at 1000r / min for 20min, add 15 parts of azodicarbonamide and 15 parts of zinc oxide, and mechanically stir at 1000r / min for 35min to obtain a mixed solution.

[0101] (2) Mix 50 parts of 2000cSt silicone rubber with 50 parts of 5000cSt silicone rubber and add 5 parts of dimethyl silicone oil, then mix evenly by mechanical stirring at 3000r / min for 35min.

[0102] (3) Mix the mixed solution obtained in (1) with the silicone rubber mixed liquid obtained in (2) evenly, and add 0.5 parts of antioxidant BHT, 0.2 parts of ultraviolet absorber UV-531 and 0.5 parts of polyethylene glycol. After mechanically stirring at 3000r / min for 1h, add 2 parts of dibutyltin dilaurate and mix and stir for 8min until uniform.

[0103] (4) Apply the well-mixed liquid obtained in step 3 to a 40*200mm area using a scraper coating method (stencil thickness 1mm). 2 The polyimide film on the copper electrode plate is etched to reduce the contact resistance between the coating and the electrode.

[0104] (5) Use an electric blower to dry the oven at 130°C for 20 minutes, cool it to room temperature, place it at room temperature for 24 hours to form, and after 7 days the performance is stable, thus obtaining the first self-temperature-controlled composite material.

[0105] A self-regulating temperature composite material with a Curie temperature of 30℃ was subjected to voltages of 9V, 20V, and 30V respectively. Temperature rise curves were obtained by measuring the temperature using a type K thermocouple, as shown in the attached figure. Figure 2 As shown, the temperature can be raised to the maximum within 4 minutes, and the temperature fluctuation remains within 1°C within 2 hours, achieving precise temperature control.

[0106] The flexibility of a material can be expressed by its degree of bending. By rolling the material to its maximum extent without breaking and then measuring its rolled diameter with vernier calipers, the minimum radius of curvature of the first self-temperature-controlled composite material in this embodiment can be obtained as 5 mm.

[0107] 2. Preparation of the second self-temperature-controlled composite material (Curie temperature point is 60℃)

[0108] (1) Add 9 parts of carbon black (particle size 70-90nm), 3 parts of carbon nanotubes (outer diameter 12-15nm, inner diameter 3-4nm, length 9-12μm) and 5 parts of nickel powder (particle size 2-2.5μm) to a 70-part mixed solution of n-hexane and xylene in a ratio of 6:1. After mixing, add 4 parts of coupling agent KH-550, sonicate for 30min, then mechanically stir at 1000r / min for 30min, add 15 parts of p-toluenesulfonyl hydrazine, and mechanically stir at 1000r / min for 30min to obtain a mixed solution.

[0109] (2) Mix 60 parts of 2000cSt silicone rubber with 40 parts of 5000cSt silicone rubber and add 5 parts of dimethyl silicone oil, then mix evenly by mechanical stirring at 4000r / min for 45min.

[0110] (3) Mix the mixed solution obtained in (1) with the silicone rubber mixed liquid obtained in (2) evenly, and add 0.3 parts of antioxidant DNT, 0.2 parts of ultraviolet absorber UV-531 and 0.3 parts of glycol. After mechanically stirring at 4000r / min for 1.5h, add 2 parts of dibutyltin dilaurate and mix and stir for 5min until uniform.

[0111] (4) Apply the well-mixed liquid obtained in step 3 to a 40*200mm area using a scraper coating method (stencil thickness 1mm). 2 The polyimide film on the copper electrode plate is etched to reduce the contact resistance between the coating and the electrode.

[0112] (5) Use an electric blower to dry the oven at 110°C for 20 minutes, then let it cool to room temperature. After being placed at room temperature for 24 hours, it will be formed and its performance will be stable after 7 days.

[0113] A second self-temperature-controlled composite material with a Curie temperature of 60℃ was subjected to voltages of 9V, 20V, and 30V respectively. Temperature rise curves were obtained by measuring the temperature using a type K thermocouple, as shown in the attached figure. Figure 3 As shown, the temperature can be raised to the maximum within 5 minutes, and the temperature fluctuation remains within 1°C within 2 hours, achieving precise temperature control.

[0114] The flexibility of a material can be expressed by its degree of bending. The material is rolled up to the maximum extent that it can bend without breaking, and then its rolling diameter is measured with vernier calipers. The minimum radius of curvature of the second self-temperature-controlled composite material is 5 mm.

[0115] 3. Preparation of flexible high thermal conductivity film (thermal conductivity of 1045 W / (m K))

[0116] (1) Pretreatment: The graphite powder was washed with dilute HCl and deionized water until neutral, filtered to obtain a solid, and then dried in a vacuum drying oven for several hours until it was completely dry.

[0117] (2) Oxidation: Slowly add 2.1 times the mass of the solid KMnO4 to the mixture of the above solid and concentrated sulfuric acid (1:1). During this process, ensure that the temperature is below 5°C. After the addition is complete, adjust the temperature to 28°C and maintain it for 30 minutes. Then dilute with deionized water, adjust the temperature to 75°C, stir magnetically for 20 minutes, and then add deionized water and H2O2 to react and remove excess KMnO4.

[0118] (3) Purification: Let the mixture stand until it separates into layers, pour off the supernatant, add an appropriate amount of dilute hydrochloric acid to the turbid liquid and let it stand until it separates into layers. Repeat this washing process. Then add deionized water to the turbid liquid, stir evenly and centrifuge. Then wash with deionized water and add water to the obtained solid GO and stir and sonicate for 2 hours to obtain GO aqueous solution.

[0119] (4) Pretreatment of dialysis bags: Cut the dialysis bags into strips of about 25cm, and then boil them in a mixed solution of deionized water, EDTA and NaHCO3. After boiling the mixed solution, rinse them several times with deionized water and set aside for later use.

[0120] (5) Preparation of GO dispersion: The GO aqueous solution obtained above was evenly divided into dialysis bags and purified by dialysis in deionized water for one week. The solution was tested with pH paper and found to be neutral. No white precipitate was generated by BaCl2 test, indicating that the impurity ions in the solution were basically removed and the GO dispersion was prepared.

[0121] (6) Preparation of flexible high thermal conductivity film: The GO dispersion was slowly poured into an evaporation tank and treated in a forced-air drying oven at 50°C for 7.5 h to obtain a graphene oxide film. The graphene oxide film was placed in a hot-pressing mold and transferred to a high-temperature tube furnace for sintering at 800°C under argon atmosphere protection. After cooling to room temperature under argon atmosphere, the flexible high thermal conductivity film was obtained. The thermal conductivity of the material was tested using a Netzsch LFA447 thermal conductivity meter, and the results are as follows: Figure 4 As shown, the thermal conductivity of the flexible high thermal conductivity film rGO-1 obtained in this embodiment is 1045 W / (m K); Figure 4The copper sample in the sample is a copper rod with a purity of 99.9%, a diameter of 25.4 mm, and a thermal conductivity of 400 W / (m K).

[0122] Thermal conductivity was tested using a Netzsch LFA467 AG (Germany). The results showed that the thermal conductivity of the flexible high thermal conductivity film in this embodiment was 1045 W / (m K). The flexible thermal conductivity film can be bent to the point of being folded in half, and can be folded in half 800 times without breaking, and can still be used normally, indicating that the flexible high thermal conductivity film has excellent flexibility.

[0123] according to Figure 1 This invention comprises an integrated component for temperature control and early warning of new energy vehicle battery packs. COMSOL software is used to simulate and calculate the battery's heat generation and dissipation at 20℃. The battery used is an 18650 lithium-ion battery with a heat generation rate of approximately 4000 W / m. 3 The simulation involves two battery packs, each containing 12 individual battery cells arranged in a 2x6 grid. The first self-temperature-controlled composite material 1 has a Curie temperature of 30°C, a thickness of 2mm, a thermal conductivity of 0.17W / (m·K), and a density of 1100Kg / m³. 3 The constant-pressure heat capacity is 1700 J / (kg·K); the Curie temperature of the second self-regulating temperature composite material 2 is 60℃, the thickness is 3 mm, the thermal conductivity is 0.19 W / (m·K), and the density is 1300 kg / m³. 3 The constant pressure heat capacity is 1500 J / (kg·K); the thermal conductivity of the flexible high thermal conductivity film 4 is 1045 W / (m·K), the thickness is 10 mm, and the density is 430 kg / m³. 3 The constant pressure heat capacity is 1410 J / (kg·K); condenser 5 uses a 380W power condenser with an internal pipe diameter of 9mm, and 32 pipes arranged in an 8*4 pattern; pump 6 is a horizontal water pump with a flow rate of 2m³ / h. 3 / h, power is 285W; water tank 8 has a volume of 10L; smart switch 3 and display 7 do not affect the simulation results, the simulation results are as follows: without any heat conduction measures, the heat generated by the battery is easy to accumulate, and the temperature rises to a maximum of 43℃ under stable conditions, such as Figure 5a As shown; however, by adopting the heat preservation and heat conduction measures in this embodiment, the heat generated by the battery can be evenly distributed, and the temperature only rises to a maximum of 37.9°C under stable conditions, as... Figure 5b As shown, the temperature is about 5°C lower than under natural conditions. This temperature is more conducive to the normal operation of the battery and extends its service life.

[0124] Example 2

[0125] 1. Preparation of the first self-temperature-controlled composite material (Curie temperature point: 35℃)

[0126] (1) Add 15 parts of carbon black (particle size 50-60 nm), 8 parts of nickel powder (particle size 2-2.5 μm) and 4 parts of aluminum silver powder (particle size 10-11.5 μm) to a 60-part mixed solution of n-hexane and ethanol in a ratio of 5:1. After mixing, add 4 parts of coupling agent KH-570, sonicate for 40 min, then mechanically stir at 1200 r / min for 25 min, add 17 parts of azodicarbonamide and 17 parts of zinc oxide, and mechanically stir at 1000 r / min for 40 min to obtain a mixed solution.

[0127] (2) Mix 20 parts of 1000cSt silicone rubber, 40 parts of 2000cSt silicone rubber and 40 parts of 10000cSt silicone rubber and add 7 parts of dimethyl silicone oil. Then, mechanically stir at 4000r / min for 40min to mix evenly.

[0128] (3) Mix the mixed solution obtained in (1) with the silicone rubber mixed liquid obtained in (2) evenly, and add 0.6 parts of antioxidant DNP, 0.3 parts of ultraviolet absorber UV-531 and 0.6 parts of polyethylene glycol. After mechanically stirring at 4000r / min for 1.5h, add 2 parts of octyltin and mix for 9min until uniform.

[0129] (4) Apply the well-mixed liquid obtained in step 3 to a 40*200mm area using a scraper coating method (stencil thickness 1mm). 2 The polyimide film on the copper electrode plate is etched to reduce the contact resistance between the coating and the electrode.

[0130] (5) Use an electric blower to dry the oven at 140°C for 18 minutes, then let it cool to room temperature. After being placed at room temperature for 24 hours, it will be formed and its performance will be stable after 7 days.

[0131] A self-regulating temperature composite material with a Curie temperature of 35℃ was subjected to voltages of 9V, 20V, and 30V respectively. Temperature rise curves were obtained by measuring the temperature using a type K thermocouple, as shown in the attached figure. Figure 6 As shown, the temperature can be raised to the maximum within 5 minutes, and the temperature fluctuation remains within 1°C within 2 hours, achieving precise temperature control.

[0132] The flexibility of a material can be expressed by its degree of bending. By rolling the material up to its maximum extent without breaking and then measuring its rolled diameter with calipers, the minimum radius of curvature of the material can be obtained. The minimum radius of curvature of this material can reach 4.5 mm.

[0133] 2. Preparation of the second self-temperature-controlled composite material (Curie temperature point is 70℃)

[0134] (1) Add 11 parts of carbon black (particle size 40-45 nm), 5 parts of aluminum silver powder (particle size 10-13 μm) and 7 parts of nickel powder (particle size 2-2.5 μm) to a 70-part mixed solution of xylene and ethanol in a ratio of 7:2. After mixing, add 5 parts of coupling agent KH-570, sonicate for 45 min, then mechanically stir at 1500 r / min for 30 min, add 10 parts of p-toluenesulfonyl hydrazine, and mechanically stir at 1500 r / min for 45 min to obtain a mixed solution.

[0135] (2) Mix 60 parts of 5000cSt silicone rubber with 40 parts of 10000cSt silicone rubber and add 6 parts of dimethyl silicone oil, then mix evenly by mechanical stirring at 4000r / min for 45min.

[0136] (3) Mix the mixed solution obtained in (1) with the silicone rubber mixed liquid obtained in (2) evenly, and add 1.0 part of antioxidant DNT, 0.5 part of ultraviolet absorber UV-531 and 0.5 part of polyethylene glycol. After mechanically stirring at 4000r / min for 1.5h, add 5 parts of octyltin and mix for 10min until uniform.

[0137] (4) Apply the well-mixed liquid obtained in step 3 to a 40*200mm area using a scraper coating method (stencil thickness 1mm). 2 The polyimide film on the copper electrode plate is etched to reduce the contact resistance between the coating and the electrode.

[0138] (5) Use an electric blower to dry the oven at 155°C for 20 minutes, then let it cool to room temperature. After being placed at room temperature for 24 hours, it will be formed and its performance will be stable after 7 days.

[0139] A second self-temperature-controlled composite material with a Curie temperature of 70℃ was subjected to voltages of 9V, 20V, and 30V respectively. Temperature rise curves were obtained by measuring the temperature using a type K thermocouple, as shown in the attached figure. Figure 7 As shown, the material can reach its maximum temperature within 4 minutes and maintain temperature fluctuations within 1°C for 2 hours, achieving precise temperature control. The material's flexibility can be represented by its degree of bending. By rolling the material to its maximum extent without breaking and then measuring its rolled diameter with calipers, the minimum radius of curvature of the material can be obtained. This material's minimum radius of curvature can reach 4.7 mm.

[0140] 3. Preparation of flexible high thermal conductivity film (thermal conductivity of 905 W / (m K))

[0141] (1) Pretreatment: The graphite powder was washed with dilute HCl and deionized water until neutral, filtered to obtain a solid, and then dried in a vacuum drying oven for several hours until it was completely dry.

[0142] (2) Oxidation: Slowly add 3 times the mass of KMnO4 to the mixture of the above solid and concentrated sulfuric acid (1:2). During this process, ensure that the temperature is below 20°C. After the addition is complete, adjust the temperature to 35°C and maintain it for 30 minutes. Then dilute with deionized water, adjust the temperature to 85°C, and stir magnetically for 30 minutes. Then add deionized water and H2O2 to react and remove excess KMnO4.

[0143] (3) Purification: The mixture was allowed to stand for separation, the supernatant was discarded, and an appropriate amount of dilute hydrochloric acid was added to the turbid liquid and allowed to stand for separation. After repeated washing, deionized water was added to the turbid liquid, the mixture was stirred evenly and centrifuged, then washed with deionized water, and water was added to the obtained solid GO and stirred and sonicated for 3 hours to obtain GO aqueous solution.

[0144] (4) Pretreatment of dialysis bags: Cut the dialysis bags into strips of about 35cm, and then boil them in a mixed solution of deionized water, EDTA and NaHCO3. After boiling the mixed solution, rinse them several times with deionized water and set aside for later use.

[0145] (5) Preparation of GO dispersion: The GO aqueous solution obtained above was evenly distributed in dialysis bags and purified by dialysis in deionized water for about one week. The solution was tested with pH paper and found to be neutral. No white precipitate was generated when tested with BaCl2, indicating that the impurity ions in the solution were basically removed and the GO dispersion was prepared.

[0146] (6) Preparation of flexible high thermal conductivity film: The GO dispersion was slowly poured into an evaporation tank and treated in a forced-air drying oven at 50°C for 8 hours to obtain a graphene oxide film. The graphene oxide film was placed in a self-made hot-press mold and transferred to a high-temperature tube furnace under argon atmosphere protection at 600°C. Finally, it was cooled to room temperature under argon atmosphere and removed to obtain the rGO-2 flexible high thermal conductivity film.

[0147] Thermal conductivity was tested using a Netzsch LFA467 PCB from Germany. The results showed that... Figure 4 As shown, the thermal conductivity of the rGO-2 flexible high thermal conductivity film is 905 W / (m K); the flexible thermal conductivity film can be bent to the point of being folded in half, and can be folded in half 600 times without breaking, and can still be used normally, indicating that the flexible high thermal conductivity film has excellent flexibility.

[0148] according to Figure 1 An integrated component for temperature control and early warning of a new energy vehicle battery pack was constructed. COMSOL software was used to simulate and calculate the battery's heat generation and dissipation at 20°C. The battery, condenser 5, pump 6, and water tank 8 were configured under the same conditions as in Example 1. The first self-regulating temperature composite material 1 had a Curie temperature of 35°C, a material thickness of 2 mm, a thermal conductivity of 0.16 W / (m·K), and a density of 1060 kg / m³. 3The constant-pressure heat capacity is 1810 J / (kg·K); the Curie temperature of the second self-regulating temperature composite material 2 is 70℃, the thickness is 4 mm, the thermal conductivity is 0.18 W / (m·K), and the density is 1400 kg / m³. 3 The constant pressure heat capacity is 1450 J / (kg·K); the thermal conductivity of the flexible high thermal conductivity film 4 is 905 W / (m·K), the thickness is 8 mm, and the density is 450 kg / m³. 3 The constant-pressure heat capacity is 1460 J / (kg·K). The simulation results are as follows: Figure 8 As shown, compared with the battery temperature rise under natural conditions, the heat preservation and heat conduction measures mentioned in this embodiment are adopted. The heat generated by the battery can be evenly distributed, avoiding excessive local temperature. Moreover, the temperature only rises to a maximum of 39.36℃ under stable conditions, which is about 3.5℃ lower than under natural conditions. This temperature is more conducive to the normal operation of the battery and extends its service life.

[0149] Example 3

[0150] 1. First self-regulating temperature composite material (Curie temperature point is 40℃)

[0151] (1) Add 16 parts of carbon black (particle size 20-30 nm), 8 parts of carbon nanotubes (outer diameter 11-13 nm, inner diameter 3-5 nm, length 9-12 μm) and 6 parts of aluminum silver powder (particle size 10-11.5 μm) to a 60-part mixed solution of hexane, ethanol and xylene in a ratio of 3:2:1. After mixing, add 5 parts of coupling agent KH-570, sonicate for 45 min, then mechanically stir at 1500 r / min for 30 min, add 20 parts of p-toluenesulfonyl hydrazine and 20 parts of zinc oxide, and mechanically stir at 1500 r / min for 45 min to obtain a mixed solution.

[0152] (2) Mix 10 parts of 2000cSt silicone rubber, 50 parts of 5000cSt silicone rubber and 40 parts of 10000cSt silicone rubber and add 8 parts of dimethyl silicone oil. Then, mechanically stir at 4000r / min for 45min until the mixture is homogeneous.

[0153] (3) Mix the mixed solution obtained in (1) with the silicone rubber mixed liquid obtained in (2) evenly, and add 0.8 parts of antioxidant DNP, 0.4 parts of ultraviolet absorber UV-531 and 0.7 parts of glycol. After mechanically stirring at 4000r / min for 1.5h, add 2 parts of octyltin and mix for 10min until uniform.

[0154] (4) Apply the well-mixed liquid obtained in step 3 to a 40*200mm area using a scraper coating method (stencil thickness 1mm). 2 The polyimide film on the copper electrode plate is etched to reduce the contact resistance between the coating and the electrode.

[0155] (5) Use an electric blower to dry the oven at 155°C for 20 minutes, then let it cool to room temperature. After being placed at room temperature for 24 hours, it will be formed and its performance will be stable after 7 days.

[0156] A self-regulating temperature composite material with a Curie temperature of 40℃ was subjected to voltages of 9V, 20V, and 30V respectively at one end. The temperature rise curves were obtained by measuring the temperature with a type K thermocouple, as shown in the attached figure. Figure 9 As shown, the temperature can be raised to the maximum within 3.5 minutes, and the temperature fluctuation remains within 1°C within 2 hours, which can achieve precise temperature control.

[0157] The flexibility of a material can be expressed by its degree of bending. By rolling the material up to its maximum extent without breaking, and then measuring its rolled diameter with vernier calipers, the minimum radius of curvature of the material can be obtained. The minimum radius of curvature of this material can reach 5.2 mm.

[0158] 2. Preparation of the second self-temperature-controlled composite material (Curie temperature point is 80℃)

[0159] (1) Add 9 parts of carbon black (particle size 20-35 nm), 5 parts of carbon nanotubes (outer diameter 13-15 nm, inner diameter 3-4 nm, length 3-5 μm) and 6 parts of aluminum silver powder (particle size 12-15 μm) to a 65-part mixed solution of n-hexane, xylene and ethanol in a ratio of 5:2:2. After mixing, add 5 parts of coupling agent KH-550, sonicate for 40 min, then mechanically stir at 1300 r / min for 30 min, add 8 parts of p-toluenesulfonyl hydrazine, and mechanically stir at 1300 r / min for 30 min to obtain a mixed solution.

[0160] (2) Mix 60 parts of 2000cSt silicone rubber with 40 parts of 10000cSt silicone rubber and add 5 parts of dimethyl silicone oil, then mechanically stir at 3500r / min for 40min to mix evenly.

[0161] (3) Mix the mixed solution obtained in (1) with the silicone rubber mixed liquid obtained in (2) evenly, and add 0.4 parts of antioxidant DNT, 0.3 parts of ultraviolet absorber UV-531 and 0.4 parts of glycol. After mechanically stirring at 3000r / min for 1.2h, add 2 parts of octyltin and mix for 10min until uniform.

[0162] (4) Apply the well-mixed liquid obtained in step 3 to a 40*200mm area using a scraper coating method (stencil thickness 1mm). 2 The polyimide film on the copper electrode plate is etched to reduce the contact resistance between the coating and the electrode.

[0163] (5) Use an electric blower to dry the oven at 130°C for 20 minutes, then let it cool to room temperature. After being placed at room temperature for 24 hours, it will be formed and its performance will be stable after 6 days.

[0164] The experiment yielded a self-temperature-controlled composite material with a Curie temperature of 80℃.

[0165] A second self-temperature-controlled composite material with a Curie temperature of 80℃ was subjected to voltages of 9V, 20V, and 30V respectively. Temperature rise curves were obtained by measuring the temperature using a type K thermocouple, as shown in the attached figure. Figure 10 As shown, the temperature can be raised to the maximum within 5 minutes, and the temperature fluctuation remains within 1°C within 2 hours, achieving precise temperature control.

[0166] The flexibility of a material can be expressed by its degree of bending. By rolling the material up to its maximum extent without breaking and then measuring its rolled diameter with calipers, the minimum radius of curvature of the material can be obtained. The minimum radius of curvature of this material can reach 6 mm.

[0167] 3. Preparation of flexible high thermal conductivity film (thermal conductivity of 775 W / (m K))

[0168] (1) Pretreatment: The graphite powder was washed with dilute HCl and deionized water until neutral, filtered to obtain a solid, and then dried in a vacuum drying oven for several hours until it was completely dry.

[0169] (2) Oxidation: Slowly add 2.5 times the mass of KMnO4 to the mixture of the above solid and concentrated sulfuric acid (1:2). During this process, ensure that the temperature is below 10°C. After the addition is complete, adjust the temperature to 30°C and maintain it for 30 minutes. Then dilute with deionized water, adjust the temperature to 80°C, stir magnetically for 20 minutes, and then add deionized water and H2O2 to react and remove excess KMnO4.

[0170] (3) Purification: The mixture was allowed to stand for separation, the supernatant was discarded, and an appropriate amount of dilute hydrochloric acid was added to the turbid liquid and allowed to stand for separation. After repeated washing, deionized water was added to the turbid liquid, the mixture was stirred evenly and centrifuged, then washed with deionized water, and water was added to the obtained solid GO and stirred and sonicated for 2.5 h to obtain GO aqueous solution.

[0171] (4) Pretreatment of dialysis bags: Cut the dialysis bags into strips of about 30cm, and then boil them in a mixed solution of deionized water, EDTA and NaHCO3. After boiling the mixed solution, rinse them several times with deionized water and set aside for later use.

[0172] (5) Preparation of GO dispersion: The GO aqueous solution obtained above was evenly distributed in dialysis bags and purified by dialysis in deionized water for about one week. The solution was tested with pH paper and found to be neutral. No white precipitate was generated when tested with BaCl2, indicating that the impurity ions in the solution were basically removed and the GO dispersion was prepared.

[0173] (6) Preparation of flexible high thermal conductivity film: The GO dispersion was slowly poured into an evaporation tank and treated in a forced-air drying oven at 55°C for 7.5 h to obtain a graphene oxide film. The graphene oxide film was placed in a self-made hot-pressing mold and transferred to a high-temperature tube furnace under argon atmosphere protection at 700°C. Finally, it was cooled to room temperature under argon atmosphere and removed to obtain the rGO-3 flexible high thermal conductivity film.

[0174] Thermal conductivity was tested using a Netzsch LFA467 PCB from Germany. The results showed that... Figure 4 As shown, the thermal conductivity of the rGO-3 flexible high thermal conductivity film is 775 W / (m K). The flexible thermal conductivity film can be bent arbitrarily to the point of being folded in half, and can be folded continuously 600 times without breaking, and can still be used normally, indicating that the flexible high thermal conductivity film has excellent flexibility.

[0175] according to Figure 1 An integrated component for temperature control and early warning of a new energy vehicle battery pack was constructed. COMSOL software was used to simulate and calculate the battery's heat generation and dissipation at 20°C. The battery, condenser 5, pump 6, and water tank 8 were configured under the same conditions as in Example 1. The first self-regulating temperature composite material 1 has a Curie temperature of 40°C, a material thickness of 3 mm, a thermal conductivity of 0.15 W / (m·K), and a density of 1200 kg / m³. 3 The constant-pressure heat capacity is 1900 J / (kg·K); the Curie temperature of the second self-regulating temperature composite material 2 is 80℃, the thickness is 3 mm, the thermal conductivity is 0.16 W / (m·K), and the density is 1550 kg / m³. 3 The constant pressure heat capacity is 1550 J / (kg·K); the thermal conductivity of the flexible high thermal conductivity film 4 is 775 W / (m·K), the thickness is 12 mm, and the density is 470 kg / m³. 3 The constant-pressure heat capacity is 1510 J / (kg·K). The simulation results are as follows: Figure 11 As shown, compared with the battery temperature rise under natural conditions, the heat preservation and heat conduction measures mentioned in this embodiment are adopted. The heat generated by the battery can be evenly distributed, avoiding excessive local temperature. Moreover, the temperature rises to a maximum of 41.12℃ under stable conditions, which is about 2℃ lower than under natural conditions. This temperature is more conducive to the normal operation of the battery and extends its service life.

Claims

1. An integrated component for temperature control and early warning of a new energy vehicle battery pack, characterized in that, The system includes a first self-regulating temperature composite material, a second self-regulating temperature composite material, a smart switch, a flexible high thermal conductivity film, a condenser, a pump, a display, and a water tank. Multiple first self-regulating temperature composite materials are present, each wrapping around each battery cell inside the new energy vehicle battery pack. These multiple first self-regulating temperature composite materials are connected in parallel to the batteries. The flexible high thermal conductivity film is tightly connected to the first self-regulating temperature composite material on each battery cell inside the new energy vehicle battery pack. One end of the flexible high thermal conductivity film is also connected to the second self-regulating temperature composite material, which is connected to the display via the smart switch. The other end of the flexible high thermal conductivity film wraps around some or all of the heat-conducting pipes connected in series by the condenser, pump, and water tank. The first self-regulating temperature composite material has a Curie temperature of 30℃-40℃; the second self-regulating temperature composite material has a Curie temperature of 60-80℃; and the flexible high thermal conductivity film has a thermal conductivity of 775-1045 W / (m K). The first self-temperature-controlled composite material is prepared through the following steps: 1) Add conductive particles to a mixed solution of organic solvents, add coupling agent after mixing, sonicate for 30-45 min, then mechanically stir at 1000-1500 r / min for 20-30 min, add foaming agent and foaming aid, and mechanically stir at 1000-1500 r / min for 30-45 min to obtain a mixed solution. 2) After mixing the silicone rubber and the diluent, mechanically stir at 3000-4000 r / min for 30-45 min to obtain a silicone rubber mixture; 3) Mix the obtained mixed solution with the silicone rubber mixture, add antioxidants, ultraviolet absorbers and other additives, and mechanically stir at 3000-4000 r / min for 1-1.5 h, then add the catalyst and mix and stir for 5-10 min until uniform; 4) Coat the mixture obtained in step 3) onto the polyimide film etched with copper electrode plates, dry, and cool to room temperature; The conductive particles are carbon black, carbon nanotubes, nickel powder, or aluminum silver powder; the particle size of carbon black is 20-90 nm; the outer diameter of carbon nanotubes is 8-15 nm, the inner diameter is 3-5 nm, and the length is 3-12 μm; the particle size of nickel powder is 2-2.5 μm; and the particle size of aluminum silver powder is 10-15 μm. The foaming agent is azodicarbonamide or p-toluenesulfonyl hydrazine; the foaming aid is zinc oxide; the crosslinking agent is tetraethyl orthosilicate; and the catalyst is octyltin or dibutyltin dilaurate.

2. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 1, characterized in that, The thickness of the flexible high thermal conductivity film is 5-15 mm; the internal valve body of the intelligent switch is a normally open single valve structure.

3. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 1, characterized in that, The method for preparing the flexible high thermal conductivity film includes the following steps: (1) Pretreatment: Wash the graphite powder until it is neutral, filter it to obtain a solid, and dry it; (2) Oxidation: Add KMnO4 to the mixture of graphite powder and concentrated sulfuric acid obtained from pretreatment, control the temperature to be below 5-10℃, after adding, adjust the temperature to 25-35℃ and maintain for 20-30 min, then dilute with deionized water, then adjust the temperature to 75-85℃, stir magnetically for 10-20 min, and add deionized water and H2O2. (3) Purification: Let the mixture stand until it separates into layers, pour off the supernatant, add dilute hydrochloric acid to the turbid liquid and let it stand to separate into layers again. Repeat this washing process. Then add deionized water to the turbid liquid, stir evenly and centrifuge. Then wash with deionized water. Add water to the obtained solid GO, stir and sonicate for 2-3 hours to obtain GO aqueous solution. (4) Preparation of GO dispersion: The GO aqueous solution was evenly distributed in the pretreated dialysis bag and purified by dialysis in deionized water for 5-10 days. The solution was tested with pH paper and found to be neutral. No white precipitate was generated when tested with BaCl2. The GO dispersion was thus prepared. (5) Preparation of flexible high thermal conductivity film: Pour the GO dispersion into the evaporation tank and treat it in the atmosphere of 50-70℃ in the drying oven for 6-8 hours to obtain graphene oxide film; put the graphene oxide film into the hot pressing mold, transfer it to the high temperature tube furnace for sintering at 600-800℃ under the protection of argon atmosphere, cool it to room temperature under argon atmosphere, and take it out to obtain flexible high thermal conductivity film.

4. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 3, characterized in that, The pretreatment described in step (1) involves washing the graphite powder sequentially with dilute HCl and deionized water until neutral, filtering to obtain a solid, and then drying it in a vacuum drying oven until it is completely dry. In step (2), the mass ratio of graphite powder to concentrated sulfuric acid is 1:1 to 1:2; the amount of KMnO4 used is 2 to 3 times the mass of the graphite powder obtained from the pretreatment. The pretreatment of the dialysis bag involves sequentially rinsing the dialysis bag with a mixed solution of deionized water, EDTA, and NaHCO3, boiling the mixed solution, and then rinsing it multiple times with deionized water.

5. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 1, characterized in that, The first self-regulating temperature composite material raw material formula, by mass parts, consists of: 100 parts silicone rubber matrix, 15-30 parts conductive particles, 3-5 parts coupling agent, 8-20 parts foaming agent, 8-20 parts foaming aid, 10-80 parts organic solvent, 2-8 parts diluent, 1-10 parts crosslinking agent, 0.5-5 parts catalyst, 0.3-1 part antioxidant, 0.2-0.5 parts ultraviolet absorber, and 0.2-0.5 parts other additives.

6. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 1, characterized in that, The silicone rubber is No. 107 silicone rubber with a viscosity of one or more of 750cSt, 1000cSt, 2000cSt, 5000cSt, and 10000cSt; the coupling agent is one of KH-550 and KH-570. The organic solvent is one or more selected from n-hexane, ethanol, and xylene; The diluent is one or more of dimethyl silicone oil and n-hexane; The antioxidant mentioned is one or more of antioxidant DNP and antioxidant BHT; The ultraviolet absorber mentioned is UV-531; The other additives mentioned are one or more of polyethylene glycol and glycol.

7. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 1, characterized in that, The second self-temperature-controlled composite material is prepared through the following steps: 1) Add conductive particles to a mixed solution of organic solvents, add coupling agent after mixing, sonicate for 30-45 min, then mechanically stir at 1000-1500 r / min for 20-30 min, add foaming agent and foaming aid, and mechanically stir at 1000-1500 r / min for 30-45 min to obtain a mixed solution. 2) After mixing the silicone rubber with the diluent, mechanically stir at 3000-4000 r / min for 30-45 min to obtain a silicone rubber mixture; 3) Mix the mixed solution with the silicone rubber mixture, add antioxidants, ultraviolet absorbers and other additives, and mechanically stir at 3000-4000 r / min for 1-1.5 h, then add the catalyst and mix for 5-10 min until uniform; 4) Coat the mixture obtained in step 3) onto a polyimide film etched with copper electrode plates, dry it, and cool it to room temperature; The conductive particles are carbon black, carbon nanotubes, nickel powder, or aluminum silver powder; wherein the carbon black has a particle size of 20-90 nm; the carbon nanotubes have an outer diameter of 8-15 nm, an inner diameter of 3-5 nm, and a length of 3-12 μm; the nickel powder has a particle size of 2-2.5 μm; and the aluminum silver powder has a particle size of 10-15 μm. The foaming agent is azodicarbonamide or p-toluenesulfonyl hydrazine; the foaming aid is zinc oxide; The crosslinking agent is tetraethyl orthosilicate; the catalyst is octyltin or dibutyltin dilaurate.

8. The integrated component for temperature control and early warning of new energy vehicle battery packs according to claim 7, characterized in that, The second self-regulating temperature composite material is composed of the following raw material formula by weight: 100 parts silicone rubber, 10-20 parts conductive particles, 2-5 parts coupling agent, 3-10 parts foaming agent, 3-10 parts foaming aid, 10-70 parts organic solvent, 2-6 parts diluent, 1-10 parts crosslinking agent, 0.5-5 parts catalyst, 0.2-1 part antioxidant, 0.2-0.5 parts ultraviolet absorber, and 0.1-0.5 parts other additives.

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