A flame-retardant heat-conducting adhesive tape for new energy vehicle thermal runaway protection and a preparation process thereof

Abstract

The application relates to the technical field of flame-retardant heat-conducting adhesive tapes, in particular to a flame-retardant heat-conducting adhesive tape for new energy automobile thermal runaway protection and a preparation process thereof. The flame-retardant heat-conducting adhesive tape for new energy automobile thermal runaway protection comprises a flame-retardant heat-conducting thermoplastic elastomer matrix, a plurality of flexible aerogel protective layers are arranged in the flame-retardant heat-conducting thermoplastic elastomer matrix, a flame-retardant heat-conducting self-adhesive layer is respectively compounded on the upper and lower surfaces of the flame-retardant heat-conducting thermoplastic elastomer matrix, a plurality of heat-conducting channels are formed through the flexible aerogel protective layers, the porosity of the flexible aerogel protective layers is 5-20 wt%, and the vertical projections of the heat-conducting channels on the adjacent flexible aerogel protective layers do not coincide. The application has good flame-retardant and heat-dissipating performances and excellent fire-flame-penetration resistance, and can improve the thermal runaway protection performance of new energy automobile battery modules.

Description

Technical Field

[0001] This invention relates to the field of flame-retardant and thermally conductive tape technology, and in particular to a flame-retardant and thermally conductive tape for thermal runaway protection in new energy vehicles and its preparation process. Background Technology

[0002] Battery modules are core components of new energy vehicles, and their performance directly affects the vehicle's range, safety, and lifespan. Thermal runaway protection is a crucial indicator of the safety of new energy vehicle battery modules, and the strength of these protections directly impacts the vehicle's driving safety, making it one of the main factors influencing consumers' purchase decisions for new energy vehicles.

[0003] Flame-retardant and thermally conductive tapes are used in new energy vehicle battery modules to provide insulation and thermal conductivity between battery cells, improving the overall vehicle's thermal runaway protection performance. Existing flame-retardant and thermally conductive tapes, made from polymer resins combined with flame retardants and thermally conductive fillers, offer some flame-retardant and thermal conductivity, but cannot address the issue of individual battery cell deflagration. When a battery cell deflagrates, the resulting instantaneous high temperature can burn through the flame-retardant and thermally conductive tape, igniting nearby battery cells and causing the entire battery module to explode, thus impacting the thermal runaway protection performance of new energy vehicle battery modules. Therefore, the inventors have provided a flame-retardant and thermally conductive tape that can prevent high-temperature burn-through and has good heat dissipation performance, along with its preparation process. Summary of the Invention

[0004] To address the technical problem of poor thermal runaway protection performance of the aforementioned flame-retardant and thermally conductive tapes, this invention provides a flame-retardant and thermally conductive tape for thermal runaway protection in new energy vehicles and its preparation process.

[0005] The present invention provides a flame-retardant and thermally conductive tape for thermal runaway protection in new energy vehicles, which is achieved through the following technical solution:

[0006] A flame-retardant and thermally conductive tape for thermal runaway protection in new energy vehicles includes a flame-retardant and thermally conductive thermoplastic elastic matrix, within which a plurality of flexible aerogel protective layers are disposed; flame-retardant and thermally conductive self-adhesive layers are respectively laminated on the upper and lower surfaces of the flame-retardant and thermally conductive thermoplastic elastic matrix; a plurality of thermally conductive channels are formed through the flexible aerogel protective layers; the porosity of the flexible aerogel protective layers is 5-20wt%; and the vertical projections of the thermally conductive channels on adjacent flexible aerogel protective layers do not overlap.

[0007] This invention has good flame retardant and heat dissipation properties, as well as excellent resistance to flame breakdown, which can improve the thermal runaway protection performance of new energy vehicle battery modules.

[0008] Preferably, the thickness of the flame-retardant and thermally conductive self-adhesive layer is 0.5-2 mm.

[0009] Preferably, the thickness of the flame-retardant and thermally conductive thermoplastic elastomer matrix is ​​4-8 mm.

[0010] Preferably, the thickness of a single layer of the flexible aerogel protective layer is 0.5-1.0 mm.

[0011] Preferably, the diameter of the heat conduction channel is 0.5-4.0 mm; the straight-line distance between the central axes of adjacent heat conduction channels is 2-3 times the diameter of the heat conduction channel.

[0012] More preferably, the diameter of the heat conduction channel is 1.8-2.4 mm; the straight-line distance between the central axes of adjacent heat conduction channels is 2.2-2.8 times the diameter of the heat conduction channel.

[0013] More preferably, the diameter of the heat conduction channel is 1 mm; the straight-line distance between the central axes of adjacent heat conduction channels is 2.2 times the diameter of the heat conduction channel, or the diameter of the heat conduction channel is 2 mm; the straight-line distance between the central axes of adjacent heat conduction channels is 2.5 times the diameter of the heat conduction channel.

[0014] By adopting the above technical solution, the flame-retardant and thermally conductive tape is given excellent flame-breakage resistance while improving the overall thermal conductivity, which enables the battery module to obtain better heat dissipation performance, thereby improving the overall thermal runaway stability of the battery module.

[0015] Preferably, the flexible aerogel protective layer is a 2-4 mm thick nano-aerogel felt, which is one of nano-silica aerogel, nano-silicon nitride aerogel, nano-boron nitride aerogel, nano-silicon carbide aerogel, mullite fiber aerogel, and alumina fiber aerogel.

[0016] By adopting the above technical solution, the flame-retardant and thermally conductive tape is endowed with excellent flame-breakage resistance.

[0017] Preferably, the flame-retardant and thermally conductive self-adhesive layer is made from the following raw materials in parts by weight: 40-50 parts butyl rubber, 10-20 parts ethylene propylene diene monomer (EPDM) rubber, 10-20 parts polybutadiene, 6-8 parts flame retardant, 20-30 parts thermally conductive filler, 1-2 parts coupling agent, 5-15 parts softener, 10-15 parts C5 petroleum resin, 1-4 parts polyethylene wax, 4-8 parts amorphous olefin copolymer, 1-2 parts vulcanizing agent, 0.5-1 part scorch inhibitor, and 1-5 parts accelerator; the softener is at least one of liquid paraffin, petrolatum, dioctyl phthalate, and dioctyl sebacate; the vulcanizing agent is at least one of sulfur, colloidal sulfur, and dicumyl oxide; and the accelerator is at least one of accelerator DCBS, accelerator NA-22, accelerator DM, accelerator TMTD, and accelerator NOBSMBS.

[0018] The flame-retardant and thermally conductive self-adhesive layer prepared by this invention has a self-adhesive strength of 2.5-3.6 N / 25 mm, a breakdown strength of ≥22.0 kV / mm, a tensile strength of ≥8.0 MPa, an elongation at break of ≥600%, a tear strength of ≥18.0 kN / m, a thermal conductivity of ≥0.50 W / (m*K), and a flame retardant rating of UL-94 V0.

[0019] The flame-retardant and thermally conductive self-adhesive layer prepared in this invention has a good damping and shock absorption effect, which can effectively release the thermal stress between individual cells and the impact stress transmitted by external vibration, and can further improve the overall thermal runaway stability and driving comfort performance of the battery module.

[0020] Preferably, the flame retardant is composed of 0.5-5 wt% of a carbon-based flame retardant, 15-20 wt% of a phosphorus-based flame retardant, 15-20 wt% of a nitrogen-based flame retardant, and 20-40 wt% of a metal hydroxide; the thermally conductive filler is at least one of alumina, boron nitride, aluminum nitride, and silicon nitride with a particle size of less than 1000 mesh.

[0021] The compounded flame retardant used in this invention can achieve excellent flame retardant performance. While ensuring flame retardant performance, the amount of flame retardant added can be reduced, thereby reducing the overall production cost. Furthermore, the reduction in the amount of flame retardant added allows for the addition of more thermally conductive fillers, which is beneficial for improving the overall heat dissipation performance and heat resistance stability.

[0022] Preferably, the flame-retardant and thermally conductive thermoplastic elastomer matrix is ​​made of flame-retardant and thermally conductive thermoplastic elastomer masterbatch, which is made of the following raw materials in parts by weight: 100 parts of TPU resin, 4-6 parts of flame retardant composition, 20-30 parts of high thermal conductivity insulating filler composition, 1-2 parts of coupling agent, 0.5-1 parts of antioxidant, 0.5-1 parts of UV stabilizer, 0.5-2 parts of zinc stearate, and 0.5-1 parts of spherical silica powder.

[0023] The flame-retardant and thermally conductive thermoplastic elastic matrix prepared in this invention has a breakdown strength ≥20.0kV / mm, tensile strength ≥25.0MPa, elongation at break ≥500%, tear strength ≥55.0kN / m, thermal conductivity ≥0.50W / (m*K), flame retardancy rating UL-94 V0, and Tg temperature ≤-25℃. Furthermore, the prepared flame-retardant and thermally conductive thermoplastic elastic matrix has excellent damping and shock absorption properties, which can effectively release the thermal stress between individual cells and the impact stress transmitted by external vibrations, further improving the overall thermal runaway stability and driving comfort of the battery module. In addition, the flame-retardant and thermally conductive thermoplastic elastic matrix has good recovery properties, which can ensure the recovery performance of the flexible aerogel protective layer and the bonding stability between the flame-retardant and thermally conductive thermoplastic elastic matrix and the flexible aerogel protective layer, avoiding the delamination problem between the flame-retardant and thermally conductive thermoplastic elastic matrix and the flexible aerogel protective layer under long-term thermal and impact stress. This is of great significance for improving the overall thermal runaway stability and thermal runaway protection durability of the battery module.

[0024] Preferably, the flame retardant composition comprises at least one of graphene, ammonium polyphosphate, melamine cyanurate, molybdenum disulfide, zinc borate whiskers, aluminum hydroxide, basic cerium carbonate, zeolite, and quartz powder.

[0025] Preferably, the high thermal conductivity insulating filler composition is composed of alumina combined with at least one of boron nitride, aluminum nitride, and silicon nitride.

[0026] The present invention uses a compounded flame retardant composition to impart excellent flame retardant properties to the flame retardant and thermally conductive thermoplastic elastic matrix. While ensuring the flame retardant properties of the flame retardant and thermally conductive thermoplastic elastic matrix, the amount of flame retardant added can be reduced, thereby reducing the overall production cost. Furthermore, the reduction in the amount of flame retardant added allows for the addition of more thermally conductive fillers, which is beneficial for improving the overall heat dissipation performance and heat resistance stability.

[0027] The present invention provides a manufacturing process for a flame-retardant and thermally conductive adhesive tape for thermal runaway protection in new energy vehicles, which is achieved through the following technical solution:

[0028] A manufacturing process for a flame-retardant and thermally conductive adhesive tape for thermal runaway protection in new energy vehicles includes the following steps:

[0029] Step 1: Preparation of flame-retardant and thermally conductive thermoplastic elastomer masterbatch;

[0030] Simultaneously, a flame-retardant and thermally conductive self-adhesive layer was prepared;

[0031] Step 2: Load the flexible aerogel protective layer into the molding die. The flame-retardant and thermally conductive thermoplastic elastic masterbatch prepared in Step 1 is melt-extruded by a screw extruder and the extrudate is filled into the molding die. After cooling and demolding, a semi-finished flame-retardant and thermally conductive tape is obtained. The semi-finished flame-retardant and thermally conductive tape includes a flame-retardant and thermally conductive thermoplastic elastic matrix and several flexible aerogel protective layers disposed on the flame-retardant and thermally conductive thermoplastic elastic matrix.

[0032] Step 3: Perform low-temperature plasma treatment on the upper and lower surfaces of the semi-finished flame-retardant and thermally conductive tape. Then, lay the flame-retardant and thermally conductive self-adhesive layer on the upper and lower surfaces of the semi-finished flame-retardant and thermally conductive tape respectively. After hot pressing, cool to room temperature. Finally, laminate release paper onto the surface of the flame-retardant and thermally conductive self-adhesive layer to obtain the finished flame-retardant and thermally conductive tape.

[0033] The preparation process of this invention is relatively simple, easy to operate, and easy to industrialize.

[0034] In summary, the present invention has the following advantages:

[0035] 1. This invention has good flame retardant and heat dissipation properties as well as excellent flame breakdown resistance, which can improve the thermal runaway protection performance of new energy vehicle battery modules.

[0036] 2. By adjusting the distribution of heat-conducting channels and the overall porosity in the flexible aerogel protective layer, this invention obtains a flame-retardant and thermally conductive tape with excellent flame-breakage resistance, as well as excellent flame-retardant and heat dissipation properties. The flame-retardant and thermally conductive tape is used between individual battery cells to give the battery module better heat dissipation performance, effectively improving the overall thermal runaway stability and driving comfort performance of the battery module.

[0037] 3. The preparation process of the present invention is relatively simple and easy to operate, making it easy to achieve industrial production. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the flame-retardant and thermally conductive tape in an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of the overall structure of the molding die for the flame-retardant and thermally conductive tape of this invention.

[0040] In the figure, 1. Flame-retardant and thermally conductive thermoplastic elastic matrix; 2. Flexible aerogel protective layer; 20. Thermal conduction channel; 3. Flame-retardant and thermally conductive self-adhesive layer; 30. Release paper; 4. Lower mold; 40. Upper mold; 41. Mold cavity; 42. Positioning groove; 43. Sealing strip placement groove; 430. Rubber sealing strip; 44. First injection hole group; 440. First injection hole; 45. Second injection hole group; 450. Second injection hole; 46. Third injection hole group; 460. Third injection hole; 5. U-shaped fastener A; 50. U-shaped fastener B; 51. U-shaped joint; 52. Connecting piece. Detailed Implementation

[0041] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples and comparative examples.

[0042] Example: Reference Figure 1 A flame-retardant and thermally conductive tape for thermal runaway protection in new energy vehicles includes a flame-retardant and thermally conductive thermoplastic elastic matrix 1, several flexible aerogel protective layers 2, and a flame-retardant and thermally conductive self-adhesive layer 3. The flexible aerogel protective layers 2 are spaced apart within the flame-retardant and thermally conductive thermoplastic elastic matrix. The flame-retardant and thermally conductive self-adhesive layer 3 is laminated to the upper and lower surfaces of the flame-retardant and thermally conductive thermoplastic elastic matrix 1.

[0043] refer to Figure 1 The flexible aerogel protective layer 2 is a 2-4 mm thick nano-aerogel felt, which is one of the following: nano-silica aerogel, nano-silicon nitride aerogel, nano-boron nitride aerogel, nano-silicon carbide aerogel, mullite fiber aerogel, or alumina fiber aerogel. Several heat-conducting channels 20 are formed throughout the flexible aerogel protective layer 2, and the porosity of the flexible aerogel protective layer 2 is 5-20 wt%. The vertical projections of the heat-conducting channels 20 on adjacent flexible aerogel protective layers 2 do not overlap.

[0044] The diameter of the heat conduction channel 20 is 0.5-4.0 mm; the straight-line distance between the central axes of adjacent heat conduction channels 20 is 2-3 times the diameter of the heat conduction channel 20. Preferably, the diameter of the heat conduction channel 20 is 1.8-2.4 mm; the straight-line distance between the central axes of adjacent heat conduction channels 20 is 2.2-2.8 times the diameter of the heat conduction channel 20.

[0045] The flame-retardant and thermally conductive self-adhesive layer is made from the following raw materials in parts by weight: 40-50 parts butyl rubber, 10-20 parts ethylene propylene diene monomer (EPDM) rubber, 10-20 parts polybutadiene, 6-8 parts flame retardant, 20-30 parts thermally conductive filler, 1-2 parts coupling agent, 5-15 parts softener, 10-15 parts C5 petroleum resin, 1-4 parts polyethylene wax, 4-8 parts amorphous olefin copolymer, 1-2 parts vulcanizing agent, 0.5-1 part anti-scorching agent, and 1-5 parts accelerator.

[0046] The softener in the flame-retardant and thermally conductive self-adhesive layer is at least one of liquid paraffin, petrolatum, dioctyl phthalate, and dioctyl sebacate. The vulcanizing agent in the flame-retardant and thermally conductive self-adhesive layer is at least one of sulfur, colloidal sulfur, and dicumyl oxide.

[0047] The accelerator in the flame-retardant and thermally conductive self-adhesive layer is at least one of the following: accelerator DCBS, accelerator NA-22, accelerator DM, accelerator TMTD, and accelerator NOBSMBS.

[0048] The coupling agent in the flame-retardant and thermally conductive self-adhesive layer is at least one of aminosilane, epoxysilane, and methacryloxysilane, preferably methacryloxysilane (such as KH570, KH571).

[0049] The anti-scorching agent in the flame-retardant and thermally conductive self-adhesive layer is CTP.

[0050] The flame retardant in the flame-retardant and thermally conductive self-adhesive layer consists of 0.5-5 wt% carbon-based flame retardant, 15-20 wt% phosphorus-based flame retardant, 15-20 wt% nitrogen-based flame retardant, and 20-40 wt% metal hydroxide.

[0051] The thermally conductive filler in the flame-retardant and thermally conductive self-adhesive layer is at least one of alumina, boron nitride, aluminum nitride, and silicon nitride with a particle size of less than 1000 mesh.

[0052] The flame-retardant and thermally conductive self-adhesive layer has a self-adhesive strength of 2.5-3.6 N / 25 mm, a breakdown strength (GB / T1408.1-2016) ≥22.0 kV / mm, a tensile strength (GB / T 1040.1-2018) ≥8.0 MPa, an elongation at break (GB / T 1040.1-2018) ≥600%, a tear strength (GB / T 5286-2008) ≥18.0 kN / m, a thermal conductivity (GBT 42919.1-2023) ≥0.50 W / (m*K), and a flame retardant rating of UL-94 V0.

[0053] The flame-retardant and thermally conductive thermoplastic elastomer matrix is ​​made from flame-retardant and thermally conductive thermoplastic elastomer masterbatch.

[0054] Flame-retardant and thermally conductive thermoplastic masterbatch is made from the following raw materials in parts by weight: 100 parts TPU resin, 4-6 parts flame retardant composition, 20-30 parts high thermal conductivity insulating filler composition, 1-2 parts coupling agent, 0.5-1 parts antioxidant, 0.5-1 parts UV stabilizer, 0.5-2 parts zinc stearate, and 0.5-1 parts spherical silica powder.

[0055] The flame retardant composition in the flame-retardant and thermally conductive thermoplastic elastic masterbatch is composed of at least one of graphene, ammonium polyphosphate, melamine cyanurate, molybdenum disulfide, zinc borate whiskers, aluminum hydroxide, basic cerium carbonate, zeolite, and quartz powder.

[0056] The high thermal conductivity insulating filler composition in flame-retardant and thermally conductive thermoplastic masterbatch is composed of alumina combined with at least one of boron nitride, aluminum nitride, and silicon nitride.

[0057] The coupling agent in the flame-retardant and thermally conductive thermoplastic masterbatch is at least one of aminosilane, epoxysilane, and methacryloxysilane, preferably aminosilane (such as KH550, KH540).

[0058] The antioxidants in the flame-retardant and thermally conductive thermoplastic masterbatch are antioxidant 1010 and antioxidant 168.

[0059] The UV stabilizers in the flame-retardant and thermally conductive thermoplastic masterbatch are UV-531 and UV-327.

[0060] The flame-retardant and thermally conductive thermoplastic elastomer matrix has the following specifications: breakdown strength (GB / T1408.1-2016) ≥20.0kV / mm, tensile strength (GB / T 1040.1-2018) ≥25.0MPa, elongation at break (GB / T 1040.1-2018) ≥500%, tear strength (GB / T 529-2008) ≥55.0kN / m, thermal conductivity (GBT 42919.1-2023) ≥0.50W / (m*K), flame retardancy rating UL-94V0, and Tg temperature ≤-25℃.

[0061] In the structural design of flame-retardant and thermally conductive tape, the thickness of the flame-retardant and thermally conductive self-adhesive layer is 0.5-2mm, the thickness of the flame-retardant and thermally conductive thermoplastic elastic matrix is ​​4-8mm, and the thickness of the single-layer flexible aerogel protective layer is 0.5-1.0mm. The test sample design is as follows: the thickness of the flame-retardant and thermally conductive self-adhesive layer is 0.5mm, the thickness of the flame-retardant and thermally conductive thermoplastic elastic matrix is ​​4mm, the flame-retardant and thermally conductive thermoplastic elastic matrix contains two flexible aerogel protective layers, the thickness of the single flexible aerogel protective layer is 0.8mm, the spacing between the flexible aerogel protective layers is 1.5mm, the length ratio of the flame-retardant and thermally conductive thermoplastic elastic matrix to the length of the single flexible aerogel protective layer is 1:0.98, and the width ratio of the flame-retardant and thermally conductive thermoplastic elastic matrix to the width of the single flexible aerogel protective layer is also 1:0.98.

[0062] refer to Figure 1 The manufacturing process of flame-retardant and thermally conductive tape used for thermal runaway protection in new energy vehicles is as follows:

[0063] Step 1: Preparation of flame-retardant and thermally conductive thermoplastic elastomer masterbatch;

[0064] Simultaneously, a flame-retardant and thermally conductive self-adhesive layer 3 was prepared;

[0065] Step 2: Load the flexible aerogel protective layer 2 into the molding die. The flame-retardant and thermally conductive thermoplastic elastic masterbatch prepared in Step 1 is melt-extruded by a screw extruder and the extrudate is filled into the molding die. After cooling and demolding, a semi-finished flame-retardant and thermally conductive tape is obtained. The semi-finished flame-retardant and thermally conductive tape includes a flame-retardant and thermally conductive thermoplastic elastic matrix 1 and two flexible aerogel protective layers 2 disposed on the flame-retardant and thermally conductive thermoplastic elastic matrix 1.

[0066] Step 3: Perform low-temperature plasma treatment on the upper and lower surfaces of the semi-finished flame-retardant and thermally conductive tape. Then, lay the flame-retardant and thermally conductive self-adhesive layer 3 on the upper and lower surfaces of the semi-finished flame-retardant and thermally conductive tape respectively. After hot pressing, cool to room temperature. Finally, laminate release paper 30 onto the surface of the flame-retardant and thermally conductive self-adhesive layer 3 to obtain the finished flame-retardant and thermally conductive tape.

[0067] Preparation Example 1: The flame-retardant and thermally conductive self-adhesive layer is composed of 40 parts butyl rubber (Yanshan Petrochemical grade 1751), 15 parts EPDM rubber (Kumho KEP330 from South Korea, provided by Guangzhou Desheng New Materials Co., Ltd.), 15 parts polybutadiene (polybutadiene D1UL, Kunshan Shengan Biotechnology Co., Ltd.), 7 parts flame retardant, 23 parts thermally conductive filler, 1.5 parts coupling agent KH570, 5 parts liquid paraffin (CAS No. 63449-39-8, chlorinated paraffin No. 52, Shandong Hengqiang Chemical Co., Ltd.), 4.5 parts dioctyl sebacate (CAS No.: 2432-87-3), 14 parts C5 petroleum resin (HHC-1100 isoprene resin, melting point 97-102℃, provided by Dongguang County Jinda Chemical Co., Ltd.), and 3 parts polyethylene wax (density 0.90-0.92 g / cm³). 3 It is made from 6 parts of amorphous olefin copolymer APAO (Jiangxi Sibo Chemical Co., Ltd., amorphous unsaturated resin APAO), 1.5 parts of vulcanizing agent-sulfur S80 (MLPC S80, Shanghai Wandao Chemical Co., Ltd.), 1 part of anti-scorching agent CTP (CAS No.: 17796-82-6), 1.5 parts of accelerator DM (CAS No.: 120-78-5), and 2 parts of accelerator NOBSMBS (Kunshan Aichao Biotechnology Co., Ltd.), with a melting point range of 105℃.

[0068] The flame retardant is composed of 2wt% multi-walled carbon nanotubes (100nm in diameter, 5-20um in length, provided by Shanghai Gaibang Industrial Co., Ltd.), 30wt% ammonium polyphosphate HT-208 (325 mesh, provided by Henan Xinzhiyuan Chemical Products Co., Ltd.), 30wt% melamine cyanurate (analytical grade AR, provided by Guangdong Wengjiang Chemical Reagent Co., Ltd.), and 38wt% ultrafine aluminum hydroxide (1250 mesh, provided by Zhengzhou Xideli Chemical New Materials Co., Ltd.). The thermally conductive filler is composed of 5 wt% spherical alumina with an average particle size of 300 nm, 15 wt% spherical alumina with an average particle size of 1 μm, 30 wt% spherical alumina with an average particle size of 2 μm, 20 wt% spherical alumina with an average particle size of 5 μm, 15 wt% spherical alumina with an average particle size of 10 μm, 10 wt% spherical alumina with an average particle size of 15 μm, 4 wt% spherical alumina with an average particle size of 30 μm, and 1 wt% boron nitride whiskers (1 μm in diameter, 10-20 μm in length, custom-made by Beijing Deco Island Gold Technology Co., Ltd.). The spherical alumina with average particle sizes of 300 nm, 1 μm, 2 μm, 5 μm, 10 μm, 15 μm, and 30 μm is supplied by Beasley New Materials (Suzhou) Co., Ltd.

[0069] The preparation method of the flame-retardant and thermally conductive self-adhesive layer is as follows:

[0070] Step 1: Mix 0.2g of multi-walled carbon nanotubes, 3g of ammonium polyphosphate, 3g of melamine cyanurate, and 3.8g of aluminum hydroxide evenly to obtain a flame retardant;

[0071] Step 2: Weigh 7g of flame retardant, 23g of thermally conductive filler, and 1.5g of KH570 coupling agent and dry knead for 30 minutes to obtain a KH570 modified flame retardant + thermally conductive filler mixture.

[0072] Step 3: Weigh 40 parts of butyl rubber (Yanshan Petrochemical grade 1751), 15 parts of EPDM rubber (Kumho KEP330 from South Korea), 15 parts of polybutadiene D1UL, 31.5 parts of the KH570 modified flame retardant + thermally conductive filler mixture prepared in Step 2, 5 parts of chlorinated paraffin 52, 4.5 parts of dioctyl sebacate, 14 parts of C5 petroleum resin HHC-1100, 3 parts of polyethylene wax, 6 parts of amorphous olefin copolymer APAO, 1.5 parts of vulcanizing agent (sulfur S80), 1 part of anti-scorching agent CTP, 1.5 parts of accelerator DM, and 2 parts of accelerator NOBSMBS and put them into a high-speed internal mixer. Heat to 70°C and mix for 30 minutes.

[0073] Step four: The mixed material obtained in step three is fed into a twin-screw extruder. The barrel temperature is 120℃, the first heating zone is 135℃, the second heating zone is 150℃, the third heating zone is 160℃, the fourth heating zone is 165℃, the fifth heating zone is 165℃, and the die head temperature is 165℃. Through the rotation and extrusion of the screw in the twin-screw extruder, it is extruded into a thin sheet at high temperature through the die, resulting in a 0.5mm thick flame-retardant and thermally conductive self-adhesive layer with a self-adhesive strength of 3.12N / 25mm, a breakdown strength of 25.0kV / mm, a tensile strength of 9.15MPa, an elongation at break of 674.6%, a tear strength of 20.9kN / m, a thermal conductivity of 0.69W / (m*K), and a flame retardant rating of UL-94 V0.

[0074] The difference between Preparation Example 2 and Preparation Example 1 is that the flame-retardant and thermally conductive self-adhesive layer is made of 40 parts of butyl rubber (Yanshan Petrochemical grade 1751), 15 parts of ethylene propylene diene monomer (EPDM) rubber (Kumho KEP330 from South Korea), 15 parts of polybutadiene D1UL, 7 parts of flame retardant, 27 parts of thermally conductive filler, 1.5 parts of coupling agent KH570, 5 parts of chlorinated paraffin 52, 4.5 parts of dioctyl sebacate, 14 parts of C5 petroleum resin HHC-1100, 3 parts of polyethylene wax, 6 parts of amorphous olefin copolymer APAO, 1.5 parts of vulcanizing agent (sulfur S80), 1 part of anti-scorching agent CTP, 1.5 parts of accelerator DM, and 2 parts of accelerator NOBSMBS.

[0075] The flame-retardant and thermally conductive self-adhesive layer has a self-adhesive strength of 2.89 N / 25 mm, a breakdown strength of 25.5 kV / mm, a tensile strength of 9.71 MPa, an elongation at break of 622.5%, a tear strength of 21.5 kN / m, a thermal conductivity of 0.74 W / (m*K), and a flame retardant rating of UL-94V0.

[0076] The difference between Preparation Example 3 and Preparation Example 1 is that the flame-retardant and thermally conductive self-adhesive layer is made of 40 parts of butyl rubber (Yanshan Petrochemical grade 1751), 15 parts of ethylene propylene diene monomer (EPDM) rubber (Kumho KEP330 from South Korea), 15 parts of polybutadiene D1UL, 6 parts of flame retardant, 30 parts of thermally conductive filler, 1.5 parts of coupling agent KH570, 5 parts of chlorinated paraffin 52, 4.5 parts of dioctyl sebacate, 14 parts of C5 petroleum resin HHC-1100, 3 parts of polyethylene wax, 6 parts of amorphous olefin copolymer APAO, 1.5 parts of vulcanizing agent (sulfur S80), 1 part of anti-scorching agent CTP, 1.5 parts of accelerator DM, and 2 parts of accelerator NOBSMBS.

[0077] The flame-retardant and thermally conductive self-adhesive layer has a self-adhesive strength of 2.78 N / 25 mm, a breakdown strength of 25.8 kV / mm, a tensile strength of 9.83 MPa, an elongation at break of 601.2%, a tear strength of 21.9 kN / m, a thermal conductivity of 0.79 W / (m*K), and a flame retardant rating of UL-94V0.

[0078] The difference between Preparation Example 4 and Preparation Example 1 is that the flame-retardant and thermally conductive self-adhesive layer is made of 40 parts of butyl rubber (Yanshan Petrochemical grade 1751), 15 parts of ethylene propylene diene monomer (EPDM) rubber (Kumho KEP330 from South Korea), 15 parts of polybutadiene D1UL, 4 parts of flame retardant, 15 parts of thermally conductive filler, 1.5 parts of coupling agent KH570, 5 parts of chlorinated paraffin 52, 4.5 parts of dioctyl sebacate, 14 parts of C5 petroleum resin HHC-1100, 3 parts of polyethylene wax, 6 parts of amorphous olefin copolymer APAO, 1.5 parts of vulcanizing agent (sulfur S80), 1 part of anti-scorching agent CTP, 1.5 parts of accelerator DM, and 2 parts of accelerator NOBSMBS.

[0079] The flame-retardant and thermally conductive self-adhesive layer has a self-adhesive strength of 3.47 N / 25 mm, a breakdown strength of 20.5 kV / mm, a tensile strength of 8.15 MPa, an elongation at break of 738.5%, a tear strength of 18.7 kN / m, a thermal conductivity of 0.48 W / (m*K), and a flame retardant rating of UL-94V1.

[0080] The difference between Preparation Example 5 and Preparation Example 1 is that the thermally conductive filler consists of 99 wt% spherical alumina with an average particle size of 5 μm and 1 wt% boron nitride whiskers. The spherical alumina with an average particle size of 5 μm was provided by Beasley New Materials (Suzhou) Co., Ltd.

[0081] The flame-retardant and thermally conductive self-adhesive layer has a self-adhesive strength of 3.02 N / 25 mm, a breakdown strength of 23.6 kV / mm, a tensile strength of 8.91 MPa, an elongation at break of 640.3%, a tear strength of 20.1 kN / m, a thermal conductivity of 0.61 W / (m*K), and a flame retardant rating of UL-94V0.

[0082] A comparison of Preparation Examples 1-3 and Preparation Example 4 shows that the flame-retardant and thermally conductive self-adhesive layer prepared with 6-8 parts of flame retardant and 20-30 parts of thermally conductive filler has good flame retardancy, thermal conductivity and mechanical properties.

[0083] A comparison of Preparation Examples 1-3 and Preparation Example 5 shows that the flame-retardant and thermally conductive self-adhesive layer prepared by using spherical alumina with average particle sizes of 300 nm, 1 μm, 2 μm, 5 μm, 10 μm, 15 μm, and 30 μm in the thermally conductive filler exhibits superior thermal conductivity, mechanical properties, and self-adhesive strength compared to the flame-retardant and thermally conductive self-adhesive layer prepared by using spherical alumina with a relatively single particle size (average particle size of 5 μm). The spherical alumina aggregate form can eliminate the porosity of the flame-retardant and thermally conductive self-adhesive layer, increase its density, and improve the overall thermal conductivity, mechanical properties, and self-adhesive strength.

[0084] The difference between Preparation Example 6 and Preparation Example 1 is that the flame-retardant and thermally conductive thermoplastic masterbatch is made from the following raw materials in parts by weight: 100 parts of TPU resin (TPU E-1180-A-10-U000 from BASF Germany, provided by Ningbo Xinmin Import & Export Co., Ltd.), 4 parts of flame retardant composition, 26 parts of high thermal conductivity insulating filler composition, 2 parts of coupling agent KH540, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 1010, 0.8 parts of UV-531, 0.2 parts of UV-327, 1 part of zinc stearate, and 1 part of spherical silica powder (average particle size 1 μm, sphericity 96%, Shijiazhuang Chaowei New Material Technology Co., Ltd.).

[0085] The flame retardant composition consists of 2 wt% graphene (industrial-grade graphene TNIRGO from Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences, with a purity >97 wt%, diameter <6 μm, number of layers <10, and specific surface area 80-120 m²). 2 The composition consists of: 6wt% molybdenum disulfide (average particle size 10μm, Hebei Ruihuang Metal Materials Co., Ltd.), 2wt% zinc borate whiskers, 30wt% ammonium polyphosphate HT-208 (325 mesh, Henan Xinzhiyuan Chemical Products Co., Ltd.), 30wt% melamine cyanurate (analytical grade AR, Guangdong Wengjiang Chemical Reagent Co., Ltd.), 25wt% aluminum hydroxide (1250 mesh, Zhengzhou Xideli Chemical New Materials Co., Ltd.), and 5wt% 4A zeolite (800 mesh, Henan Zhongyan Bio-New Materials Co., Ltd.).

[0086] Preparation method of zinc borate whiskers: 24.1g of dodecyloxybisphosphate salt was added to a mixed solution containing 80.7g zinc sulfate, 46.4g boric acid and 40.0g sodium hydroxide. Sodium hydroxide solution was added to the mixed solution while stirring continuously to adjust the pH of the mixed solution to 9. Then the solution was poured into a reaction vessel and reacted at 240℃ for 22h to obtain a white product. The white powder obtained by filtration, washing and vacuum drying was placed in a planetary ball mill and ball-milled at 60rpm for 10min to obtain zinc borate whiskers.

[0087] The high thermal conductivity insulating filler composition consists of 5 wt% spherical alumina with an average particle size of 300 nm, 15 wt% spherical alumina with an average particle size of 1 μm, 30 wt% spherical alumina with an average particle size of 2 μm, 20 wt% spherical alumina with an average particle size of 5 μm, 15 wt% spherical alumina with an average particle size of 10 μm, 10 wt% spherical alumina with an average particle size of 15 μm, 4 wt% spherical alumina with an average particle size of 30 μm, and 1 wt% boron nitride whiskers (1 μm in diameter, 10-20 μm in length, custom-made by Beijing Deco Island Gold Technology Co., Ltd.). The spherical alumina with average particle sizes of 300 nm, 1 μm, 2 μm, 5 μm, 10 μm, 15 μm, and 30 μm is supplied by Beasley New Materials (Suzhou) Co., Ltd.

[0088] The preparation method of flame-retardant and thermally conductive thermoplastic elastic masterbatch is as follows:

[0089] Step 1: Weigh 2 parts by weight of industrial-grade graphene TNIRGO, 6 parts by weight of molybdenum disulfide with an average particle size of 10 μm, 2 parts by weight of zinc borate whiskers, 30 parts by weight of ammonium polyphosphate HT-208, 30 parts by weight of melamine cyanurate, 25 parts by weight of 1250 mesh aluminum hydroxide, and 5 parts by weight of 800 mesh 4A zeolite, and mix them evenly to obtain the flame retardant composition.

[0090] Simultaneously weigh 1.5 parts by weight of spherical alumina with an average particle size of 300 nm, 4.5 parts by weight of spherical alumina with an average particle size of 1 μm, 9 parts by weight of spherical alumina with an average particle size of 2 μm, 6 parts by weight of spherical alumina with an average particle size of 5 μm, 4.5 parts by weight of spherical alumina with an average particle size of 10 μm, 3 parts by weight of spherical alumina with an average particle size of 15 μm, 1.2 parts by weight of spherical alumina with an average particle size of 30 μm, and 0.3 parts by weight of boron nitride whiskers, and mix them to obtain a high thermal conductivity insulating filler composition;

[0091] Step 2: Weigh 4 parts by mass of the flame retardant composition, 26 parts by mass of the high thermal conductivity insulating filler composition, and 2 parts by mass of the coupling agent KH540, and dry knead for 30 minutes to obtain KH540 modified filler.

[0092] Step 3: Place 100 parts of TPU resin E-1180-A-10-U000, 32 parts of KH540 modified filler from Step 2, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 1010, 0.8 parts of UV-531, 0.2 parts of UV-327, 1 part of zinc stearate, and 1 part of spherical silica powder in a high-speed dispersion kettle and disperse at 200 rpm for 1 hour. The resulting mixture is fed into a twin-screw extruder. The seven temperature zones of the twin-screw extruder are set as follows: Zone 1 160℃, Zone 2 170℃, Zone 3 180℃, Zone 4 190℃, Zone 5 195℃, Zone 6 195℃, Zone 7 195℃, and the die head temperature is 195℃. The resulting molten extrudate is drawn, cooled with silicone oil, and then fed into a granulator. It is then cut and granulated to obtain semi-finished TPU particles with a particle size of 3-4 mm.

[0093] Step four: The obtained semi-finished TPU particles are heat-treated at 80℃ for 6 hours to obtain the finished flame-retardant and thermally conductive thermoplastic elastic TPU masterbatch, with a Shore hardness of 89A, a breakdown strength of 22.5kV / mm, a tensile strength of 44.78MPa, an elongation at break of 581.4%, a tear strength of 63.7kN / m, a thermal conductivity of 0.75W / (m*K), a flame retardant rating of UL-94 V0, and a limiting oxygen index of 31.8%.

[0094] The difference between Preparation Example 7 and Preparation Example 1 is that the flame-retardant and thermally conductive thermoplastic masterbatch is made from the following raw materials in parts by weight: 100 parts of TPU resin - BASF E-1180-A-10-U000, 4 parts of flame retardant composition, 20 parts of high thermal conductivity insulating filler composition, 2 parts of coupling agent KH540, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 1010, 0.8 parts of UV-531, 0.2 parts of UV-327, 1 part of zinc stearate, and 1 part of spherical silica powder with an average particle size of 1 μm.

[0095] The flame-retardant and thermally conductive thermoplastic elastomer has a Shore hardness of 87A, a breakdown strength of 20.9kV / mm, a tensile strength of 41.25MPa, an elongation at break of 630.4%, a tear strength of 59.8kN / m, a thermal conductivity of 0.67W / (m*K), a flame retardant rating of UL-94V0, and a limiting oxygen index of 30.3%.

[0096] The difference between Preparation Example 8 and Preparation Example 1 is that the flame-retardant and thermally conductive thermoplastic masterbatch is made from the following raw materials in parts by weight: 100 parts of TPU resin - BASF E-1180-A-10-U000, 4 parts of flame retardant composition, 30 parts of high thermal conductivity insulating filler composition, 2 parts of coupling agent KH540, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 1010, 0.8 parts of UV-531, 0.2 parts of UV-327, 1 part of zinc stearate, and 1 part of spherical silica powder with an average particle size of 1 μm.

[0097] The flame-retardant and thermally conductive thermoplastic elastomer has a Shore hardness of 91A, a breakdown strength of 23.1 kV / mm, a tensile strength of 46.15 MPa, an elongation at break of 565.2%, a tear strength of 65.1 kN / m, a thermal conductivity of 0.79 W / (m*K), a flame retardant rating of UL-94V0, and a limiting oxygen index of 32.4%.

[0098] The difference between Preparation Example 9 and Preparation Example 1 is that the flame retardant composition consists of 30 wt% ammonium polyphosphate HT-208 (325 mesh, Henan Xinzhiyuan Chemical Products Co., Ltd.), 30 wt% melamine cyanurate (analytical grade AR, Guangdong Wengjiang Chemical Reagent Co., Ltd.), and 40 wt% aluminum hydroxide (1250 mesh, Zhengzhou Xideli Chemical New Materials Co., Ltd.).

[0099] The flame-retardant and thermally conductive thermoplastic elastomer has a Shore hardness of 89A, a breakdown strength of 22.8kV / mm, a tensile strength of 42.85MPa, an elongation at break of 574.6%, a tear strength of 61.6kN / m, a thermal conductivity of 0.72W / (m*K), a flame retardant rating of UL-94V0, and a limiting oxygen index of 30.7%.

[0100] The difference between Preparation Example 10 and Preparation Example 1 is that the high thermal conductivity insulating filler composition consists of 99 wt% spherical alumina with an average particle size of 5 μm and 1 wt% boron nitride whiskers (1 μm in diameter and 10-20 μm in length, custom-made by Beijing Deco Island Gold Technology Co., Ltd.). The spherical alumina with an average particle size of 5 μm was provided by Beasley New Materials (Suzhou) Co., Ltd.

[0101] The flame-retardant and thermally conductive thermoplastic elastomer has a Shore hardness of 87A, a breakdown strength of 19.8kV / mm, a tensile strength of 38.51MPa, an elongation at break of 565.8%, a tear strength of 57.2kN / m, a thermal conductivity of 0.68W / (m*K), a flame retardant rating of UL-94V0, and a limiting oxygen index of 29.9%.

[0102] The difference between Preparation Example 11 and Preparation Example 1 is that the flame-retardant and thermally conductive thermoplastic masterbatch is made from the following raw materials in parts by weight: 100 parts of TPU resin - BASF E-1180-A-10-U000, 3 parts of flame retardant composition, 15 parts of high thermal conductivity insulating filler composition, 2 parts of coupling agent KH540, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 1010, 0.8 parts of UV-531, 0.2 parts of UV-327, 1 part of zinc stearate, and 1 part of spherical silica powder with an average particle size of 1 μm.

[0103] The flame-retardant and thermally conductive thermoplastic elastomer has a Shore hardness of 87A, a breakdown strength of 18.2kV / mm, a tensile strength of 37.09MPa, an elongation at break of 685.1%, a tear strength of 56.1kN / m, a thermal conductivity of 0.51W / (m*K), a flame retardancy rating of UL-94V1, and a limiting oxygen index of 27.1%.

[0104] The difference between Preparation Example 12 and Preparation Example 1 is that the flame-retardant and thermally conductive thermoplastic masterbatch is made from the following raw materials in parts by weight: 100 parts of TPU resin - BASF E-1180-A-10-U000, 4 parts of flame retardant composition, 32 parts of high thermal conductivity insulating filler composition, 2 parts of coupling agent KH540, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 1010, 0.8 parts of UV-531, 0.2 parts of UV-327, 1 part of zinc stearate, and 1 part of spherical silica powder with an average particle size of 1 μm.

[0105] The flame-retardant and thermally conductive thermoplastic elastomer has a Shore hardness of 91A, a breakdown strength of 23.3kV / mm, a tensile strength of 46.42MPa, an elongation at break of 525.4%, a tear strength of 65.3kN / m, a thermal conductivity of 0.80W / (m*K), a flame retardant rating of UL-94V0, and a limiting oxygen index of 32.6%.

[0106] A comparison of Preparation Examples 6-8 and Preparation Example 9 shows that the flame-retardant and thermally conductive thermoplastic elastic masterbatch prepared using the flame-retardant composition in Preparation Example 6 has better flame-retardant properties.

[0107] A comparison of Preparation Examples 6-8 with Preparation Example 10 shows that the flame-retardant and thermally conductive thermoplastic elastomer prepared by using spherical alumina with average particle sizes of 300 nm, 1 μm, 2 μm, 5 μm, 10 μm, 15 μm, and 30 μm in the thermally conductive filler composition has superior thermal conductivity, mechanical properties, and self-adhesive strength compared to the flame-retardant and thermally conductive thermoplastic elastomer prepared by using spherical alumina with a relatively single particle size (average particle size of 5 μm). The spherical alumina aggregate form can eliminate the porosity of the flame-retardant and thermally conductive thermoplastic elastomer, increase the density of the flame-retardant and thermally conductive thermoplastic elastomer matrix, and improve the overall thermal conductivity, mechanical properties, and self-adhesive strength.

[0108] A comparison of preparation examples 6-8 and preparation examples 11-12 shows that the flame-retardant and thermally conductive thermoplastic elastic masterbatch prepared with an addition amount of 4 parts of flame retardant composition and an addition amount of 20-30 parts of high thermal conductivity insulating filler composition has good flame retardant properties as well as good mechanical strength, bonding strength and insulation safety performance.

[0109] Example 1: See Figure 1 The flame-retardant and thermally conductive tape for thermal runaway protection in new energy vehicles includes a flame-retardant and thermally conductive thermoplastic elastic matrix 1, several flexible aerogel protective layers 2, and a flame-retardant and thermally conductive self-adhesive layer 3. The flexible aerogel protective layers 2 are spaced apart within the flame-retardant and thermally conductive thermoplastic elastic matrix. The flame-retardant and thermally conductive self-adhesive layer 3 is laminated to the upper and lower surfaces of the flame-retardant and thermally conductive thermoplastic elastic matrix.

[0110] The flame-retardant and thermally conductive thermoplastic elastomer matrix 1 is made from the flame-retardant and thermally conductive thermoplastic elastomer masterbatch in Preparation Example 6. The flame-retardant and thermally conductive self-adhesive layer 3 is the flame-retardant and thermally conductive self-adhesive layer in Preparation Example 1. The flexible aerogel protective layer is a silica nano-aerogel felt with a thickness of 0.8 mm, custom-made by Nanotech Co., Ltd.

[0111] See Figure 1The flame-retardant and thermally conductive self-adhesive layer 3 has a thickness of 0.5 mm, and the flame-retardant and thermally conductive thermoplastic elastic matrix 1 has a thickness of 4 mm. The flame-retardant and thermally conductive thermoplastic elastic matrix 1 contains two flexible aerogel protective layers 2. Each flexible aerogel protective layer 2 has a thickness of 0.8 mm, and the spacing between the flexible aerogel protective layers 2 is 1.5 mm. The length ratio of the flame-retardant and thermally conductive thermoplastic elastic matrix 1 to the length of each flexible aerogel protective layer 2 is 1:0.98, and the width ratio of the flame-retardant and thermally conductive thermoplastic elastic matrix 1 to the width of each flexible aerogel protective layer 2 is also 1:0.98. Several thermally conductive channels 20 are formed through each flexible aerogel protective layer 2, and the vertical projections of the thermally conductive channels 20 on adjacent flexible aerogel protective layers 2 do not overlap. The diameter of the heat conduction channel 20 of the flexible aerogel protective layer 2 is 1 mm, the straight distance between the central axes of adjacent heat conduction channels 20 is 2.2 mm, and the porosity of the flexible aerogel protective layer 2 is 16.2 wt%.

[0112] refer to Figure 2 The molding die for flame-retardant and thermally conductive tape includes a lower die 4 and an upper die 40. A mold cavity 41 is fitted inside the lower die 4. Two rows of positioning grooves 42 are formed inside the mold cavity 41, each fixing a flexible aerogel protective layer. The distance between the two flexible aerogel protective layers is 1.2 mm. These two flexible aerogel protective layers are labeled as flexible aerogel protective layer A and flexible aerogel protective layer B. A sealing strip placement groove 43 is formed on the upper surface of the lower die 4. When the lower die 4 and the upper die 40 are closed, the rubber sealing strip 430 is fitted into the sealing strip placement groove 43 of the lower die 4, and the lower die 4 and the upper die 40 are sealed and closed using fastening bolts.

[0113] refer to Figure 2 The lower mold has three side surfaces, each with a first injection hole group 44, a second injection hole group 45, and a third injection hole group 46 that communicate with the mold cavity 41. The first injection hole 440 in the first injection hole group 44 has a diameter of 6 mm, and the spacing between adjacent first injection holes 440 is 18 mm. The second injection hole 450 in the second injection hole group 45 has a diameter of 6 mm, and the spacing between adjacent second injection holes 450 is 18 mm. The third injection hole 460 in the third injection hole group 46 has a diameter of 6 mm, and the spacing between adjacent third injection holes 460 is 18 mm. The horizontal projection of the first injection hole group 44 falls between the flexible aerogel protective layer A and the bottom surface of the mold cavity 41. The horizontal projection of the second injection hole group 45 falls between the flexible aerogel protective layer A and the flexible aerogel protective layer B. The horizontal projection of the third injection hole group 46 falls between the flexible aerogel protective layers B.

[0114] refer to Figure 2The fixing method of flexible aerogel protective layer A and flexible aerogel protective layer B in the molding die for flame-retardant and thermally conductive tape is as follows: U-shaped fasteners A5 are heat-pressed to the four corners of flexible aerogel protective layer A. The U-shaped fasteners A5 fit into the positioning grooves 42 in the mold cavity 41, thus fixing flexible aerogel protective layer A in the lower mold 4. U-shaped fasteners B50 are heat-pressed to the four corners of flexible aerogel protective layer B. The U-shaped fasteners B50 fit into the positioning grooves 42 in the mold cavity 41, thus fixing flexible aerogel protective layer B in the lower mold 4. The spacing between flexible aerogel protective layers A and B is 1.2mm.

[0115] refer to Figure 2 U-shaped fasteners A5 and B50 have the same structure and are both injection molded using the flame-retardant and thermally conductive thermoplastic elastic masterbatch from Preparation Example 6. Taking U-shaped fastener A5 as an example, U-shaped fastener A5 includes a U-shaped knot 51 and a connecting piece 52 integrally injection molded at the bottom of the U-shaped knot. The U-shaped knot 51 is hot-pressed onto the upper and lower surfaces of the flexible aerogel protective layer A, and the connecting piece 52 is fitted into the positioning groove 42 of the mold cavity 41.

[0116] The manufacturing process of a flame-retardant and thermally conductive adhesive tape for thermal runaway protection in new energy vehicles is as follows:

[0117] Step 1, Preparation of flame-retardant and thermally conductive thermoplastic elastic masterbatch, see Preparation Example 6;

[0118] Simultaneously, a flame-retardant and thermally conductive self-adhesive layer was prepared, see Preparation Example 1;

[0119] Step two: Load two layers of flexible aerogel protective layers (0.8mm thick silica nano-aerogel felt, custom-made by Nano Technology Co., Ltd.) into the molding mold. The specific installation method is as follows: First, heat-press U-shaped fasteners A5 onto the four corners of one silica nano-aerogel felt. Then, fit the silica nano-aerogel felt with U-shaped fasteners A5 into a row of positioning grooves 42 below the mold cavity 41. Next, heat-press U-shaped fasteners B50 onto the four corners of the other silica nano-aerogel felt. Then, fit the silica nano-aerogel felt with U-shaped fasteners B50 into a row of positioning grooves 42 above the mold cavity 41. The two layers of silica nano-aerogel felt are spaced 1.2 mm apart. The flame-retardant and thermally conductive thermoplastic elastic masterbatch in Preparation Example 6 is fed into a screw extruder. The seven temperature zones of the twin-screw extruder are set as follows: Zone 1 160℃, Zone 2 170℃, Zone 3 180℃, Zone 4 190℃, Zone 5 200℃, Zone 6 200℃, Zone 7 200℃, and the die head temperature is 200℃. The molten extrudate extruded from the die head is injected into the molding die. The screw speed is 65 rpm, the injection pressure is 78 MPa, the holding pressure is 54 MPa, the holding pressure is 8 min, the back pressure is 0.5 MPa, and the die temperature is 55℃. After cooling, demolding, and trimming, a semi-finished flame-retardant and thermally conductive tape is obtained.

[0120] Step 3: Perform low-temperature plasma treatment on the upper and lower surfaces of the semi-finished flame-retardant and thermally conductive tape at a temperature of 4°C and a treatment gas of nitrogen for 5 minutes. After the low-temperature plasma treatment, lay the flame-retardant and thermally conductive self-adhesive layer from Preparation Example 1 on the upper and lower surfaces of the semi-finished flame-retardant and thermally conductive tape respectively. After hot pressing at 80°C and 9.8N pressure for 120 seconds, allow it to cool naturally to room temperature. Finally, laminate release paper onto the surface of the flame-retardant and thermally conductive self-adhesive layer to obtain the finished flame-retardant and thermally conductive tape.

[0121] The difference between Example 2 and Example 1 is that the flame-retardant and thermally conductive thermoplastic elastic matrix 1 is made from the flame-retardant and thermally conductive thermoplastic elastic masterbatch in Preparation Example 7. The flame-retardant and thermally conductive self-adhesive layer 3 is the flame-retardant and thermally conductive self-adhesive layer in Preparation Example 1.

[0122] The difference between Example 3 and Example 1 is that the flame-retardant and thermally conductive thermoplastic elastic matrix 1 is made from the flame-retardant and thermally conductive thermoplastic elastic masterbatch in Preparation Example 8. The flame-retardant and thermally conductive self-adhesive layer 3 is the flame-retardant and thermally conductive self-adhesive layer in Preparation Example 1.

[0123] The difference between Example 4 and Example 1 is that the flame-retardant and thermally conductive thermoplastic elastic matrix 1 is made from the flame-retardant and thermally conductive thermoplastic elastic masterbatch in Preparation Example 6. The flame-retardant and thermally conductive self-adhesive layer 3 is the flame-retardant and thermally conductive self-adhesive layer in Preparation Example 2.

[0124] The difference between Example 5 and Example 1 is that the flame-retardant and thermally conductive thermoplastic elastic matrix 1 is made from the flame-retardant and thermally conductive thermoplastic elastic masterbatch in Preparation Example 6. The flame-retardant and thermally conductive self-adhesive layer 3 is the flame-retardant and thermally conductive self-adhesive layer in Preparation Example 3.

[0125] The difference between Example 6 and Example 1 is that the flame-retardant and thermally conductive thermoplastic elastic matrix 1 is made from the flame-retardant and thermally conductive thermoplastic elastic masterbatch in Preparation Example 8. The flame-retardant and thermally conductive self-adhesive layer 3 is the flame-retardant and thermally conductive self-adhesive layer in Preparation Example 3.

[0126] The difference between Example 7 and Example 1 is that the flexible aerogel protective layer is a 0.8 mm thick nano-silicon carbide aerogel, synthesized in the laboratory of Xi'an Jiaotong University. To meet the requirement of sufficient disclosure of nano-silicon carbide aerogel synthesis technology, the following existing methods for synthesizing nano-silicon carbide aerogel are provided:

[0127] Step 1: Mix 20g of dimethyldimethoxysilane, 10g of methyltrimethoxysilane and 12.3g of distilled water, use 10g of ethanol as solvent, add 2ml of 1mol / L nitric acid, and hydrolyze at 90℃ for 2h to obtain a polysiloxane sol with a viscosity of 12mPa·s.

[0128] Step 2: Using a porous carbon fiber material with dimensions of 280mm×160mm×0.8mm as a skeleton, a polysiloxane sol with a viscosity of 12mPa·s is impregnated into its interior through negative pressure impregnation.

[0129] Step 3: Place the impregnated sample in the surrounding environment for 12 hours to form a ceramic precursor. Place it in a vacuum drying oven at 70°C for 8 hours to allow the sol in the porous carbon fiber material to fully gel. Then heat it in argon to 1500°C for pyrolysis, hold it at that temperature for 1 hour, and cool it to room temperature in the furnace.

[0130] Step 4: Place the pyrolyzed sample in an air furnace and keep it at 900℃ for 2 hours. Remove the porous carbon fiber skeleton by thermal oxidation to obtain nano-silicon carbide aerogel with dimensions of 280mm×160mm×0.8mm.

[0131] The difference between Example 8 and Example 1 is that the flexible aerogel protective layer is a 0.8 mm thick boron nitride nano-aerogel synthesized by the Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences. To meet the requirement of sufficient disclosure of the synthesis technology of boron nitride nano-aerogel, the following existing synthesis method of boron nitride nano-aerogel is given: S1. Add 0.01g boric acid, 0.01g melamine and 0.5g urea to 120mL of ethanol / tert-butanol mixed solution (ethanol to tert-butanol volume ratio 5:3), and stir in a 40℃ water bath until the solution becomes transparent; S2. Sonicate the transparent solution in S1. at 15℃ and 100W for 5min to obtain a white boric acid / melamine-urea saline gel; S3. Place the white boric acid / melamine-urea saline gel in S2 in a freeze dryer and freeze-dry for 12h to obtain boric acid / melamine-urea salt aerogel; S4. Pyrolyze the boric acid / melamine-urea salt aerogel in S3 at 1300℃ under an argon atmosphere for 6h to obtain flexible boron nitride nanobelt aerogel.

[0132] The difference between Example 9 and Example 1 is that the diameter of the heat conduction channel 20 of the flexible aerogel protective layer 2 is 2 mm, the straight distance between the central axes of adjacent heat conduction channels 20 is 3 mm, and the porosity of the flexible aerogel protective layer 2 is 12.3 wt%.

[0133] The difference between Example 10 and Example 1 is that the diameter of the heat conduction channel 20 of the flexible aerogel protective layer 2 is 4 mm, the straight distance between the central axes of adjacent heat conduction channels 20 is 12 mm, and the porosity of the flexible aerogel protective layer 2 is 8.9 wt%.

[0134] The difference between Comparative Example 1 and Example 1 is that in step two, the two flexible aerogel protective layers 2 were not loaded into the molding die. Instead, the flame-retardant and thermally conductive thermoplastic elastic masterbatch from Preparation Example 6 was directly fed into the screw extruder. The seven temperature zones of the twin-screw extruder were set as follows: Zone 1 160°C, Zone 2 170°C, Zone 3 180°C, Zone 4 190°C, Zone 5 200°C, Zone 6 200°C, Zone 7 200°C, and the die head temperature was 200°C. The molten extrudate from the die head was injected into the molding die. The screw speed was 65 rpm, the injection pressure was 78 MPa, the holding pressure was 54 MPa, the holding pressure was 8 min, the back pressure was 0.5 MPa, and the die temperature was 55°C. After cooling and demolding, the semi-finished flame-retardant and thermally conductive tape was obtained. The remaining steps were the same.

[0135] The difference between Comparative Example 2 and Example 1 is that the diameter of the heat conduction channel 20 of the flexible aerogel protective layer 2 is 1 mm, the straight distance between the central axes of adjacent heat conduction channels 20 is 4 mm, and the porosity of the flexible aerogel protective layer 2 is 4.8 wt%.

[0136] The difference between Comparative Example 3 and Example 1 is that the diameter of the heat conduction channel 20 of the flexible aerogel protective layer 2 is 2 mm, the straight distance between the central axes of adjacent heat conduction channels 20 is 9.2 mm, and the porosity of the flexible aerogel protective layer 2 is 4.9 wt%.

[0137] The difference between Comparative Example 4 and Example 1 is that the diameter of the heat conduction channel 20 of the flexible aerogel protective layer 2 is 4 mm, the straight distance between the central axes of adjacent heat conduction channels 20 is 17 mm, and the porosity of the flexible aerogel protective layer 2 is 4.7 wt%.

[0138] Table 1: Test parameters of flame-retardant thermally conductive tapes in Examples 1-10 and Comparative Examples 1-4

[0139]

[0140] Note: Test method for flame burn-through resistance: Use an alcohol torch to conduct a burn-through test on the flame-retardant thermally conductive tape. The flame height of the alcohol torch is D1, and the distance between the flame of the alcohol torch and the surface of the flame-retardant thermally conductive tape is D2, where D2=0.99D1. The alcohol torch continuously burns the flame-retardant thermally conductive tape for 300 seconds. Observe whether the flame-retardant thermally conductive tape is burned through. If it is not burned through, the flame-retardant thermally conductive tape is considered qualified.

[0141] As can be seen from Examples 1-10 and Comparative Example 1, and Table 1, the addition of a flexible aerogel protective layer can effectively improve the overall flame-retardant and thermally conductive tape's resistance to flame breakdown and improve the thermal runaway protection performance of new energy vehicle battery modules.

[0142] As can be seen from Examples 1-10 and Comparative Examples 2-4 and Table 1, the porosity of the flexible aerogel protective layer is controlled at 5-20 wt%, which can give the flame-retardant and thermally conductive tape good overall heat dissipation performance. Preferably, the porosity of the flexible aerogel protective layer is controlled at 12-18 wt%, and the diameter of the thermal conductive channel is 1-2 mm.

[0143] Combining Examples 1 and 7-8 with Table 1, it can be seen that the flame-retardant thermally conductive tape prepared using specially formulated nano-silicon carbide aerogel or nano-boron nitride aerogel exhibits improved heat dissipation performance and positively contributes to resistance to electrical breakdown. Furthermore, considering the high-temperature resistance of nano-silicon carbide aerogel and nano-boron nitride aerogel, the flame-retardant thermally conductive tape prepared using these materials demonstrates better resistance to extreme high temperatures, thus enhancing the thermal runaway protection performance of battery modules. However, industrial mass production needs to consider commercialization issues. The production cost of flame-retardant thermally conductive tape prepared using commercially available silica nano-aerogel felt is significantly lower than that prepared using nano-silicon carbide aerogel or nano-boron nitride aerogel. Therefore, silica nano-aerogel felt is the preferred material for industrial production.

[0144] In summary, the flame-retardant and thermally conductive tape of this invention has good flame-retardant and heat dissipation properties as well as excellent flame-breakdown resistance, which can improve the thermal runaway protection performance of new energy vehicle battery modules.

Claims

1. A flame-retardant heat-conductive adhesive tape for thermal runaway protection of new energy vehicles, characterized in that: The application relates to a fire-retardant and heat-conducting thermoplastic elastomer base (1) provided with a plurality of flexible aerogel protective layers (2); the upper and lower surfaces of the fire-retardant and heat-conducting thermoplastic elastomer base (1) are respectively compounded with fire-retardant and heat-conducting self-adhesive layers (3); the flexible aerogel protective layer (2) is provided with a plurality of heat-conducting channels (20); the opening rate of the flexible aerogel protective layer (2) is 5-20 wt%; the vertical projections of the heat-conducting channels (20) on adjacent flexible aerogel protective layers (2) do not coincide; the diameter of the heat-conducting channel (20) is 0.5-4.0 mm; the straight-line distance between the central axes of adjacent heat-conducting channels (20) is 2-3 times the diameter of the heat-conducting channel (20). ​ 2.The flame-retardant and heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 1, characterized in that: The diameter of the heat-conducting channel (20) is 1.8-2.4 mm; the straight-line distance between the central axes of adjacent heat-conducting channels (20) is 2.2-2.8 times the diameter of the heat-conducting channel (20). 3.The flame-retardant and heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 1, characterized in that: The flexible aerogel protective layer (2) is a 2-4 mm thick nanometer aerogel felt, and the nanometer aerogel felt is one of nanometer silicon dioxide aerogel, nanometer silicon nitride aerogel, nanometer boron nitride aerogel, nanometer silicon carbide aerogel, mullite fiber aerogel and alumina fiber aerogel. 4.The flame-retardant and heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 1, characterized in that: The fire-retardant and heat-conducting self-adhesive layer (3) is made of the following raw materials: 40-50 parts of butyl rubber, 10-20 parts of ethylene-propylene-diene rubber, 10-20 parts of polybutadiene, 6-8 parts of a fire retardant, 20-30 parts of a heat-conducting filler, 1-2 parts of a coupling agent, 5-15 parts of a softener, 10-15 parts of C5 petroleum resin, 1-4 parts of polyethylene wax, 4-8 parts of amorphous olefin copolymer, 1-2 parts of a vulcanizing agent, 0.5-1 part of an anti-scorching agent, and 1-5 parts of an accelerator; the softener is at least one of liquid paraffin, vaseline, dioctyl phthalate and dioctyl sebacate; the vulcanizing agent is at least one of sulfur, colloidal sulfur and cumene hydroperoxide; and the accelerator is at least one of accelerator DCBS, accelerator NA-22, accelerator DM, accelerator TMTD and accelerator NOBSMBS. 5.The flame-retardant and heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 4, characterized in that: The fire retardant is composed of 0.5-5 wt% of a carbon-based fire retardant, 15-20 wt% of a phosphorus-based fire retardant, 15-20 wt% of a nitrogen-based fire retardant and 20-40 wt% of a metal hydroxide; and the heat-conducting filler is at least one of alumina, boron nitride, aluminum nitride and silicon nitride with a particle size less than 1000 mesh. 6.The flame-retardant heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 5, characterized in that: The self-adhesive strength of the fire-retardant and heat-conducting self-adhesive layer (3) is 2.5-3.6 N / 25 mm, the breakdown strength is greater than or equal to 22.0 kV / mm, the tensile strength is greater than or equal to 8.0 MPa, the elongation at break is greater than or equal to 600%, the tear strength is greater than or equal to 18.0 kN / m, the heat conductivity is greater than or equal to 0.50 W / (m*K), and the fire-retardant performance is UL-94 V0 level. 7.The flame-retardant and heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 1, characterized in that: The flame-retardant heat-conductive thermoplastic elastomer base (1) is made of a flame-retardant heat-conductive thermoplastic elastomer master batch, which is made of the following raw materials: 100 parts of TPU resin, 4-6 parts of a flame retardant composition, 20-30 parts of a high-thermal-conductivity insulating filler composition, 1-2 parts of a coupling agent, 0.5-1 part of an antioxidant, 0.5-1 part of an ultraviolet-resistant agent, 0.5-2 parts of zinc stearate, and 0.5-1 part of spherical silica powder; the flame retardant composition is composed of at least one of graphene, ammonium polyphosphate, melamine cyanurate, molybdenum disulfide, zinc borate whiskers, aluminum hydroxide, basic cerium carbonate, zeolite, and quartz powder; and the high-thermal-conductivity insulating filler composition is composed of at least one of aluminum oxide, boron nitride, aluminum nitride, and silicon nitride. 8.The flame-retardant and heat-conductive adhesive tape for thermal runaway prevention of new energy vehicles according to claim 7, characterized in that: The flame-retardant heat-conductive thermoplastic elastomer base (1) has a breakdown strength of ≥20.0 kV / mm, a tensile strength of ≥25.0 MPa, an elongation at break of ≥500%, a tear strength of ≥55.0 kN / m, a thermal conductivity of ≥0.50 W / (m*K), a flame-retardant performance of UL-94 V0 level, and a Tg temperature of ≤-25℃.

9. A preparation process of the fire-retardant heat-conductive adhesive tape for new energy vehicle thermal runaway protection according to any one of claims 1-8, characterized in that: The method comprises the following steps: Step one: preparation of a flame-retardant heat-conductive thermoplastic elastomer master batch; Meanwhile, a flame-retardant heat-conductive self-adhesive layer (3) is prepared; Step two: loading the flexible aerogel protective layer (2) into a molding mold, and filling the extrudate obtained by melting and extruding the flame-retardant heat-conductive thermoplastic elastomer master batch prepared in step one into the molding mold through a screw extruder, and cooling and demolding to obtain a semi-finished flame-retardant heat-conductive adhesive tape, which comprises a flame-retardant heat-conductive thermoplastic elastomer base (1) and a plurality of flexible aerogel protective layers (2) arranged on the flame-retardant heat-conductive thermoplastic elastomer base (1); Step three: low-temperature plasma treatment is performed on the upper and lower surfaces of the semi-finished flame-retardant heat-conductive adhesive tape, and then the flame-retardant heat-conductive self-adhesive layer (3) is respectively laid on the upper and lower surfaces of the semi-finished flame-retardant heat-conductive adhesive tape, and after hot pressing and cooling to room temperature, a release paper (30) is finally compounded on the surface of the flame-retardant heat-conductive self-adhesive layer (3) to obtain a finished flame-retardant heat-conductive adhesive tape.

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