Ultrahigh-temperature-resistant impact-resistant ceramic silica gel composite belt for vehicle and preparation method thereof

Abstract

The invention relates to the technical field of preparation of a ceramic silica gel composite belt for a power battery of a new energy automobile, in particular to a super-high-temperature-resistant and impact-resistant ceramic silica gel composite belt for an automobile and a preparation method of the super-high-temperature-resistant and impact-resistant ceramic silica gel composite belt. The phase change toughening effect of the core-shell structure filler is generally utilized to generate pressure stress, inhibit crack propagation and improve fracture toughness through volume change during phase change, meanwhile, the core-shell structure filler is subjected to thermal expansion coefficient gradient structure design, interface stress in the core-shell structure filler at high temperature is relieved, thermal stress concentration is avoided, thermal shock resistance is improved, and the service life of the core-shell structure filler is prolonged. And the ceramic layer is prevented from cracking, so that the ceramic layer has good high-temperature resistance and flame retardance, flame spreading can be effectively prevented, and thermal runaway of the power battery is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing ceramicized silica gel composite tapes for power batteries of new energy vehicles, and particularly relates to a super high temperature resistant and impact resistant ceramicized silica gel composite tape for vehicles and a preparation method thereof. Background Art

[0002] A ceramicized composite tape is a material that can quickly ceramicize in a high temperature environment to form a hard ceramic layer. This ceramic layer has good high temperature resistance and flame retardant properties, can effectively prevent the spread of fire, and prevent the power battery from causing a fire when abnormal situations such as thermal runaway occur, thus gaining time for personnel evacuation and fire fighting and rescue.

[0003] Moreover, it can play a certain heat insulation role, reduce the transfer of heat inside the power battery to the external environment, and at the same time prevent external heat from entering the battery interior, which helps to maintain the temperature stability of the battery working environment, improve the performance and service life of the battery, and to a certain extent inhibit the occurrence of thermal runaway.

[0004] For example, in the invention patent with the patent application number 2022117146768, it specifically discloses a ceramicized composite tape for fire prevention and high temperature insulation of power batteries and its preparation and application, achieving the flame retardant performance and ceramifiable performance of the ceramicized composite tape while ensuring a thickness of 0.15 - 0.5 mm.

[0005] However, the use of glass micro powder, zinc borate, aluminum hydroxide, and magnesium hydroxide in the above-mentioned invention patent for the ceramicized composite tape forms a "rigid particle filled brittle system", where cracks are prone to initiate and rapidly expand at the interface of the fillers, resulting in a decrease in fracture toughness. At the same time, the inorganic fillers (such as glass micro powder CTE≈(5 - 10)×10 -6 / °C) and the silicone matrix (CTE≈(200 - 300)×10 -6 / °C) have a large difference. When the temperature is high or changes suddenly, the matrix around the fillers generates thermal stress concentration due to inconsistent shrinkage / expansion, and the thermal shock resistance fails, resulting in the initiation of microcracks. Especially when thermal runaway occurs in the power battery, a large amount of gas such as carbon dioxide, carbon monoxide, hydrogen, and methane will be generated inside the battery. Once the ceramic layer cannot withstand the gas impact and cracks appear, the ceramic layer will instantly fail, leading to the explosion of the power battery.

[0006] Therefore, there is an urgent need for a technical solution that can maintain flame retardant performance and ceramifiable performance at a low thickness, while avoiding a decrease in fracture toughness and the failure of thermal shock resistance. Summary of the Invention

[0007] In view of the above problems, the present invention provides a vehicle - used ultra - high temperature and impact - resistant ceramizable silicone composite tape and a preparation method thereof. By using core - shell structure fillers to replace the original ceramic - forming fillers, the phase - change toughening effect of the core - shell structure fillers usually generates compressive stress through volume change during phase change, inhibits crack propagation, and improves fracture toughness. At the same time, the core - shell structure fillers are designed with a thermal expansion coefficient gradient structure to relieve the interfacial stress inside the core - shell structure fillers at high temperatures, avoid thermal stress concentration, enhance thermal shock resistance, and prevent the ceramic layer from cracking. Furthermore, the ceramic layer has good high - temperature resistance and flame - retardant properties, can effectively prevent the spread of fire, and prevent thermal runaway of power batteries.

[0008] To achieve the above object, the present invention provides the following technical solutions: A vehicle - used ultra - high temperature and impact - resistant ceramizable silicone composite tape, comprising: A substrate layer, a ceramizable tape layer, and an adhesive layer stacked in sequence; The ceramizable tape layer is formed by curing a ceramizable glue, and the ceramizable glue contains the following components in parts by weight, 100 parts of an organosilicon rubber matrix; 30 - 60 parts of ceramic - forming fillers; 10 - 30 parts of inorganic flame - retardant fillers; 1 - 5 parts of a cross - linker; 0.5 - 2 parts of a coupling agent; Among them, the ceramic - forming filler is a core - shell structure filler, which has a borosilicate glass as the core and a nanoscale zirconia shell layer on the surface. The nanoscale zirconia has a particle size of 50 - 100 nm and a coating rate of ≥95%.

[0009] As an improvement, the organosilicon rubber matrix is selected from at least one of methyl vinyl silicone rubber, vinyl - terminated methyl vinyl silicone rubber, and methyl vinyl MQ silicone resin; the inorganic flame - retardant filler is selected from at least one of aluminum hydroxide and magnesium hydroxide; the cross - linker is selected from at least one of dicumyl peroxide and di - tert - butyl peroxide; the coupling agent is selected from silane coupling agent KH550 or KH560.

[0010] As an improvement, the melting point of the borosilicate glass is 650 ± 50 °C, and the chemical composition of the borosilicate glass is 55 - 65 wt% of SiO 2 、15 - 25 wt% of B 2 O 3 、5 - 15 wt% of Na 2 O, the impurity content is ≤1 wt%, and the particle size is 1 - 5 μm.

[0011] As an improvement, the particle size of the nanoscale zirconia shell layer is 50 - 100 nm, the crystal form is tetragonal or monoclinic, and is doped with Y2 O 3 Stable treatment, the shell thickness is 5 - 20 nm, and after surface hydroxylation treatment, a silane coupling agent is grafted.

[0012] Borosilicate glass (such as SiO 2 -B 2 O 3 -Na 2 O system) can have a melting point as low as 600 - 800 °C, and rapidly melts at high temperature to form a continuous glass phase, serving as a "liquid-phase bridge" for the ceramization reaction, promoting the diffusion and sintering of metal oxides (such as Al 2 O 3 , MgO). For example, at 600 °C, a dense ceramic shell can be formed within 30 seconds for the borosilicate glass core, with a significantly improved efficiency compared to traditional ceramization materials (requiring several hours of heat preservation above 600 °C). At the same time, nanoscale zirconia (ZrO 2 ) undergoes a tetragonal phase → monoclinic phase transformation under stress, with a volume expansion of 3 - 5%, absorbing the energy of crack propagation and increasing the flexural strength of the ceramized layer by more than 40%. For example, the flexural strength of a pure borosilicate glass ceramized layer is 50 MPa, while it can reach 70 MPa after coating with nanoscale ZrO 2 .

[0013] In addition, the thermal expansion coefficient of borosilicate glass (3.3×10 -6 / °C) is close to that of the silicone rubber matrix (2×10 -5 / °C), which can relieve the interfacial stress at high temperature, further avoid cracking of the ceramic layer, and has good corrosion resistance, being able to resist the erosion of the ceramized layer by a humid heat environment (such as 85 °C / 85%RH), with a volume resistivity decrease of ≤10% (30% for traditional materials). After the surface of nanoscale ZrO 2 is treated with a silane coupling agent, a covalent bond is formed with the silicone rubber matrix, and the interfacial shear strength is increased from 4 MPa to 8 MPa.

[0014] As an improvement, the core-shell structure filler further includes Al 2 O 3 in the intermediate layer. The thickness of the Al 2 O 3 intermediate layer is 2 - 5 nm, prepared by atomic layer deposition, so that the Al 2 O 3 coating rate on the surface of the borosilicate glass core is ≥98%, used to match the difference in thermal expansion coefficients between borosilicate glass and zirconia.

[0015] It should be emphasized here that the thermal expansion coefficient of nanoscale ZrO 2 is (10×10 -6 / °C), and that of borosilicate glass is (3.3×10-6 / °C) varies greatly. During the high-temperature ceramization process, stress concentration will occur, resulting in a decrease in the bonding force at the core-shell interface. To solve this problem, the present invention innovatively adopts Al 2 O 3 intermediate layer to form an outer layer of nano-ZrO 2 thermal expansion coefficient (10×10 -6 / °C), the intermediate alumina thermal expansion coefficient ((7 - 8)×10 -6 / °C), and the internal borosilicate glass thermal expansion coefficient (3.3×10 -6 / °C) thermal expansion coefficient gradient buffer structure to eliminate the problem of large thermal expansion coefficient difference between nano-ZrO 2 and borosilicate glass, significantly reducing the interfacial stress concentration. Experiments have shown that the interfacial stress of the composite material without the alumina intermediate layer can reach 50 MPa at high temperature, while it drops to below 15 MPa after addition. At the same time, the hydroxyl groups on the surface of alumina form hydrogen bonds with the silanol groups of the silicone rubber matrix, and the interfacial bonding strength is increased by 50%. Nano-alumina particles (particle size 50 - 100 nm) are embedded in the silicone rubber matrix to form a mechanical interlocking structure, and the shear strength is increased from 4 MPa to 8 MPa.

[0016] Specifically, the core melts to absorb stress, the borosilicate glass melts at high temperature, and part of the thermal stress is absorbed through plastic flow. The intermediate layer has a gradient transition. The thermal expansion coefficient of the alumina intermediate layer is between the core and the shell, forming a stress gradient buffer zone. The shell undergoes phase transformation toughening, and the phase transformation of nano-ZrO 2 absorbs the energy for crack propagation, further inhibiting stress concentration. Under the combined action, the thermal stress concentration coefficient of the composite material is reduced from 3.5 of the traditional material to 1.2, significantly improving the thermal shock resistance.

[0017] Furthermore, the core melting provides a liquid phase, the melting of the borosilicate glass promotes the diffusion of metal oxides, shortening the ceramization time. The intermediate layer catalyzes sintering. Alumina, as a catalyst for the ceramization reaction, reduces the sintering activation energy, lowering the ceramization temperature from 800 °C to 600 °C. The shell inhibits crystallization. The high surface energy of nano-ZrO 2 inhibits the crystallization of the glass phase, forming a denser ceramic layer. Under the synergistic action, the composite material can form a continuous ceramic shell within 30 seconds at 600 °C, with an efficiency improvement of 80% compared to the traditional material.

[0018] Regarding the mechanical properties, the core provides rigid support, the borosilicate glass ceramic layer provides high-temperature rigidity (Mohs hardness 5), and the intermediate layer enhances toughness: the directional arrangement of the glass fibers in the alumina intermediate layer increases the flexural strength of the composite material by 40% (from 50 MPa to 70 MPa). The shell toughens and protects: nano-ZrO 2The transformation toughening increases the fracture toughness (KIC) of the ceramic layer from 2 MPa·m¹ / ² to 5 MPa·m¹ / ². The improvement in comprehensive performance enables the composite material to have a volume resistivity decrease of ≤10% after being placed in an 85°C / 85%RH environment for 1000 hours (the traditional material has a 30% decrease).

[0019] As an improvement, the preparation method of the core-shell structure filler includes the following steps: Step a: Disperse borosilicate glass powder in an ethanol-aqueous solution with an ethanol-water volume ratio of 1:1 and a concentration of 50-100 g / L. Ultrasonically disperse for 30 min, filter the dispersed borosilicate glass powder, wash it with absolute ethanol 2-3 times, and vacuum dry it at 60-80°C until constant weight to ensure surface dryness. Utilize the cavitation effect of ultrasonic waves to break particle agglomeration, combine with the polarity matching of the ethanol-water mixed solvent to achieve uniform dispersion of the glass powder. At the same time, the addition of ethanol reduces the surface tension of water, improves the wettability of the glass powder (polar surface), and avoids the decrease in dispersion stability caused by the too strong volatility of pure ethanol or the particle agglomeration caused by the too high surface tension of pure water; Step b: Deposit an Al 2 O 3 intermediate layer on the surface of the glass powder by atomic layer deposition. The reaction temperature is 100-150°C, the precursors are trimethylaluminum and deionized water, and the number of cycles is 50-100 times. Trimethylaluminum is used as the aluminum source with high reaction activity. The by-product of the reaction with water to form Al 2 O 3 is volatile methane without residue. Deionized water is used as the oxygen source, which is safe, easy to obtain, and has strong reaction controllability. Each single ALD cycle generates about 0.1-0.2 nm thick Al 2 O 3 . 50-100 cycles can form a 5-20 nm uniform coating. As the intermediate layer, the thickness is appropriate. If it is too thin (<5 nm), it may not effectively isolate the direct contact between the inner core glass powder and the outer ethyl zirconate. If it is too thick (>20 nm), it increases the filler density and the cost rises; Step c: Add the glass powder coated with Al 2 O 3 to an ethyl zirconate hydrolysis solution with a concentration of 0.1-0.3 mol / L. The concentration of the hydrochloric acid catalyst in the ethyl zirconate hydrolysis solution is 0.01-0.05 mol / L. Stir at 60-80°C for 2-4 h, filter and dry to obtain the core-shell structure filler. Specifically, ethyl zirconate (Zr(OC 2 H 5 ) 4 ) undergoes hydrolysis and polycondensation. Through the sol-gel method, a ZrO 2 O 3 shell layer is formed on the surface of the glass powder coated with Al 2 . The reaction equation can be simplified as: Hydrolysis: Zr(OC 2 H 5 ) 4 + 4H 2 O → Zr(OH) 4 + 4C 2 H 5 OH Polycondensation: nZr(OH) 4 → (ZrO 2 ) n + 2nH 2 O Al 2 O 3 The -OH groups in the intermediate layer form hydrogen bonds with the hydroxyl groups in the ZrO 2 gel and are converted into chemical bonds (Al-O-Zr) after calcination, enhancing the core-shell interface bonding and preventing the shell layer from peeling off.

[0020] As an improvement, in step b, the thermal expansion coefficient of the Al 2 O 3 intermediate layer is (8 - 10)×10 -6 / °C, which is between the thermal expansion coefficient of borosilicate glass (3 - 5)×10 -6 / °C and the thermal expansion coefficient of zirconia (10 - 12)×10 -6 / °C, forming a gradient thermal expansion matching structure.

[0021] As an improvement, the mass ratio of the inorganic flame retardant filler to the core-shell structure filler is (1:1)-(1:3), the particle size of the inorganic flame retardant filler is 5 - 10 μm, and the surface is modified with stearic acid.

[0022] As an improvement, the substrate layer is one of fiberglass cloth, aramid fiber cloth or basalt fiber cloth, with a thickness of 50 - 100 μm; the adhesive layer is an organosilicon pressure-sensitive adhesive or an acrylate pressure-sensitive adhesive, with a solid content ≥90% and a peel strength ≥15 N / cm.

[0023] In addition, the present invention also provides a method for preparing a vehicle-use ultra-high temperature resistant and impact-resistant ceramized silica gel composite tape described in any one of the above, comprising the following steps: Step t1, preparation of ceramizing glue: Premix the organosilicon rubber matrix for 10 min, degas it under vacuum for 30 min, with a vacuum degree ≤100 Pa, sequentially add the core-shell filler, inorganic flame retardant filler, coupling agent, and mix for 30 min until evenly dispersed, then add the cross-linking agent and continue to mix for 20 min to form a uniform paste-like ceramizing glue, with a viscosity of 50 - 100 Pa·s at a shear rate of 100 s -1 ; Step t2, pretreatment of the substrate layer. After cleaning the substrate to remove surface impurities and oil stains, perform surface activation treatment on the substrate; Step t3, coating with ceramizing glue. Adopt the method of scraping or roll coating to evenly coat the ceramizing glue on the pretreated substrate layer, with a thickness of 0.1 - 0.3 mm; Step t4, curing treatment. Put the substrate layer coated with ceramizing glue into an oven for curing treatment. Set the curing temperature to 120 - 150 °C and the curing time to 1 - 2 h to fully cure the ceramizing glue to form a ceramizing tape layer; Step t5, composite adhesive layer. Evenly coat the adhesive on the surface of the ceramizing tape layer, with a coating thickness of 0.02 - 0.05 mm. Through the method of roll pressing or laminating, make the adhesive layer closely combine with the ceramizing tape layer. After the composite is completed, place it at room temperature for 24 h to obtain a super high temperature resistant and impact resistant ceramizing silica gel composite tape for vehicles.

[0024] The beneficial effects of the present invention are as follows: (1) The present invention has excellent high temperature resistance and impact resistance. The ceramic filler adopts a core - shell structure design, with borosilicate glass as the core (melting point 650 ± 50 °C), and a nanoscale zirconia shell layer (particle size 50 - 100 nm) coated on the surface. And through the Al 2 O 3 intermediate layer (thickness 2 - 5 nm) to achieve a gradient matching of the coefficient of thermal expansion (borosilicate glass (3 - 5) × 10 -6 / °C → Al 2 O 3 (8 - 10) × 10 -6 / °C → zirconia (10 - 12) × 10 -6 / °C). This structure can form a dense ceramic layer in a high - temperature environment, effectively resisting thermal shock. At the same time, the high - strength nanocrystalline structure of the shell layer zirconia (tetragonal or monoclinic phase, stabilized by Y 2 O 3 treatment) significantly improves the impact resistance of the composite tape, avoiding cracking failure caused by sudden temperature changes or mechanical stress; (2) The present invention has high - efficiency flame retardancy and environmental protection characteristics. The inorganic flame - retardant fillers (aluminum hydroxide, magnesium hydroxide) and the core - shell structure fillers are compounded in a mass ratio of (1:1) - (1:3), and the surface of the fillers is modified with stearic acid and grafted with a silane coupling agent to ensure uniform dispersion in the silicone rubber matrix. During combustion, the inorganic flame - retardant fillers release crystal water to absorb heat and lower the temperature, the borosilicate glass melts to form an insulating layer, and the zirconia shell layer maintains the ceramic skeleton structure. The three work together to achieve halogen - free flame retardancy, with excellent flame - retardant performance and meeting environmental protection requirements, suitable for high - safety scenarios in vehicles; (3) The present invention has excellent interfacial compatibility and mechanical stability. The surface of the core-shell filler is hydroxylated and grafted with a silane coupling agent (KH550 or KH560), forming a chemical bond with the silicone rubber matrix. Combining with the Al 2 O 3 intermediate layer (coating rate ≥ 98%) prepared by atomic layer deposition effectively improves the interfacial compatibility between the filler and the matrix, reduces stress concentration. The crosslinking agent (such as dicumyl peroxide) promotes the matrix to form a three-dimensional network structure. Cooperating with high-strength substrates such as fiberglass cloth (thickness 50 - 100 μm), the composite tape has both high tensile strength and flexibility, and is not prone to delamination or fracture during long-term use; (4) The present invention has good practical processability and adaptability. The substrate layer is made of high-temperature resistant fiber materials such as fiberglass cloth and aramid fiber cloth, and the adhesive layer uses silicone pressure-sensitive adhesive or acrylate pressure-sensitive adhesive (solid content ≥ 90%, peel strength ≥ 15 N / cm), which not only meets the bonding stability under high-temperature environment but also facilitates construction and lamination. The surface activation treatment and roll coating / knife coating processes in the preparation process ensure tight bonding between layers and are suitable for industrial continuous production.

[0025] In summary, the present invention has excellent high-temperature resistance and impact resistance, efficient flame retardancy and environmental protection characteristics, etc., and is particularly suitable for the field of ceramicized silicone rubber technology for new energy vehicle power batteries. Description of the Drawings

[0026] Figure 1 It is a schematic flow chart of the preparation method of the core-shell structure filler in Example 1 of the present invention; Figure 2 It is a schematic flow chart of the preparation method of the vehicle-used ultra-high temperature resistant and impact resistant ceramicized silicone rubber composite tape in Example 2 of the present invention. Detailed Description of the Invention

[0027] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and a single point value, and between single point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0028] The following details the specific embodiments of the present invention. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the appended claims.

[0029] All publications, patent applications, patents, and other references mentioned in this specification are hereby incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0030] When this specification uses prefixes such as "well-known to those skilled in the art", "prior art", or their similar terms to introduce materials, substances, methods, steps, devices, or components, etc., the objects introduced by such prefixes cover those commonly used in the art at the time when the present invention is proposed, but also include those that are not commonly used at present but will become recognized by the art as suitable for similar purposes.

[0031] It should be specifically noted that two or more aspects (or embodiments) disclosed in the context of this specification can be combined with each other arbitrarily, and the technical solutions thus formed (such as methods or systems) belong to a part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0032] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless it does not conform to the common understanding of those skilled in the art when based on weight.

[0033] Example 1: As Figure 1 shown, the preparation method of the core-shell structure filler includes the following steps: Step a: Disperse borosilicate glass powder in an ethanol-aqueous solution with an ethanol-water volume ratio of 1:1 and a concentration of 50 - 100 g / L, ultrasonically disperse for 30 min, filter the dispersed borosilicate glass powder, wash it with absolute ethanol 2 - 3 times, and vacuum dry it at 60 - 80 °C to constant weight to ensure surface dryness; Step b: Deposit an Al 2 O 3 intermediate layer on the surface of the glass powder by atomic layer deposition method, with a reaction temperature of 100 - 150 °C, trimethylaluminum and deionized water as precursors, and 50 - 100 cycles. Note that the dried glass powder needs to be fully preheated (consistent with the reaction temperature) in the ALD equipment, and an appropriate particle dispersion method (such as a fluidized bed) is adopted to ensure uniform contact of the precursors; Step c: Add the Al 2 O 3 coated glass powder into an ethyl zirconate hydrolysis solution with a concentration of 0.1 - 0.3 mol / L, where the concentration of hydrochloric acid catalyst in the ethyl zirconate hydrolysis solution is 0.01 - 0.05 mol / L, stir at 60 - 80 °C for 2 - 4 h, and obtain the core-shell structure filler after filtration and drying.

[0034] The mass ratio of the inorganic flame retardant filler to the core-shell structure filler is (1:1)-(1:3). The particle size of the inorganic flame retardant filler is 5-10 μm, and the surface is treated with stearic acid modification.

[0035] Example 2: As Figure 2 shown, a method for preparing a vehicle-used ultra-high temperature resistant and impact-resistant ceramized silica gel composite tape includes the following steps: Step t1, preparation of ceramizing glue: Premix the organosilicon rubber matrix for 10 min, degas it under vacuum for 30 min with a vacuum degree ≤ 100 Pa. Sequentially add the core-shell filler, inorganic flame retardant filler, and coupling agent, and knead for 30 min until evenly dispersed. Then add the cross-linking agent and continue kneading for 20 min to form a uniform paste-like ceramizing glue. The viscosity at a shear rate of 100 s -1 is 50-100 Pa·s; Step t2, pretreatment of the base material layer: Clean the base material to remove surface impurities and oil stains, and then perform surface activation treatment on the base material; Step t3, coating the ceramizing glue: Adopt the scraping or roller coating method to evenly coat the ceramizing glue on the pretreated base material layer with a thickness of 0.1-0.3 mm; Step t4, curing treatment: Put the base material layer coated with the ceramizing glue into an oven for curing treatment. Set the curing temperature to 120-150 °C and the curing time to 1-2 h to fully cure the ceramizing glue to form a ceramized tape layer; Step t5, composite of the adhesive layer: Evenly coat the adhesive on the surface of the ceramized tape layer with a coating thickness of 0.02-0.05 mm. Through the roller pressing or laminating method, make the adhesive layer tightly combined with the ceramized tape layer. After the composite is completed, place it at room temperature for 24 h to obtain the vehicle-used ultra-high temperature resistant and impact-resistant ceramized silica gel composite tape.

[0036] The base material layer is one of glass fiber cloth, aramid fiber cloth, or basalt fiber cloth, with a thickness of 50-100 μm; the adhesive layer is an organosilicon pressure-sensitive adhesive or an acrylate pressure-sensitive adhesive, with a solid content ≥ 90% and a peel strength ≥ 15 N / cm.

[0037] Preparation Example 1: Raw material composition (parts by weight): Organosilicon rubber matrix: 100 parts of methyl vinyl silicone rubber; Ceramic-forming filler (core-shell structure filler): 45 parts (the melting point of the borosilicate glass core is 650 °C, Al 2 O 3 The thickness of the intermediate layer is 3 nm, and the thickness of the zirconia shell layer is 10 nm); Inorganic flame retardant filler: 20 parts of aluminum hydroxide (particle size 7 μm, modified with stearic acid); Crosslinking agent: 3 parts of dicumyl peroxide; Coupling agent: 1.25 parts of silane coupling agent KH550; The preparation steps are the same as those in Example 2: Preparation of core-shell filler: The number of cycles in step b is 75 times, and the hydrolysis temperature in step c is 70 °C and the time is 3 h; Preparation of ceramizable glue: The viscosity at a shear rate of 100 s -1 is 75 Pa·s; Base material layer: fiberglass cloth (thickness 75 μm); Adhesive layer: silicone pressure-sensitive adhesive (solid content 95%, peel strength 18 N / cm).

[0038] Preparation Example 2: Raw material composition (parts by weight): Organosilicon rubber matrix: 100 parts of vinyl-terminated methyl vinyl silicone rubber; Ceramic-forming filler (core-shell structure filler): 30 parts (borosilicate glass core particle size 1 μm, Al 2 O 3 intermediate layer thickness 2 nm, zirconia shell layer thickness 5 nm); Inorganic flame retardant filler: 10 parts of magnesium hydroxide (particle size 5 μm, modified with stearic acid); Crosslinking agent: 1 part of di-tert-butyl peroxide; Coupling agent: 0.5 part of silane coupling agent KH560; The preparation steps are the same as those in Example 2: Preparation of core-shell filler: The number of cycles in step b is 50 times, and the hydrolysis temperature in step c is 60 °C and the time is 2 h; Preparation of ceramizable glue: The viscosity at a shear rate of 100 s -1 is 50 Pa·s; Base material layer: aramid fiber cloth (thickness 50 μm); Adhesive layer: acrylate pressure-sensitive adhesive (solid content 90%, peel strength 15 N / cm).

[0039] Preparation Example 3: Raw material composition (parts by weight): Organosilicon rubber matrix: 100 parts of methyl vinyl MQ silicone resin; Ceramic-forming filler (core-shell structure filler): 50 parts (Al 2 O 3 intermediate layer thickness 5 nm, zirconia shell layer particle size 80 nm); Inorganic flame retardant filler: 15 parts of aluminum hydroxide (particle size 10 μm, modified with stearic acid); Crosslinking agent: 4 parts of dicumyl peroxide; Coupling agent: 1.5 parts of silane coupling agent KH550; The preparation steps are the same as those in Example 2: Preparation of core-shell filler: The number of cycles in step b is 100 times, and the hydrolysis temperature in step c is 80 °C and the time is 4 h; Preparation of ceramized glue: The viscosity at a shear rate of 100 s -1 is 85 Pa·s; Base material layer: basalt fiber cloth (thickness 100 μm); Adhesive layer: organosilicon pressure-sensitive adhesive (solid content 92%, peel strength 20 N / cm).

[0040] Preparation Example 4: Raw material composition (parts by weight): Organosilicon rubber matrix: 70 parts of methyl vinyl silicone rubber + 30 parts of methyl vinyl MQ silicone resin; Ceramic-forming filler (core-shell structure filler): 55 parts (the crystal form of the zirconia shell layer is monoclinic, and KH560 is grafted on the surface); Inorganic flame retardant filler: 25 parts of magnesium hydroxide (particle size 8 μm, modified with stearic acid); Crosslinking agent: 2 parts of di-tert-butyl peroxide; Coupling agent: 2 parts of silane coupling agent KH550; The preparation steps are the same as those in Example 2: Preparation of core-shell filler: The pulse time of trimethylaluminum in step b is 1 s, and the concentration of hydrochloric acid catalyst in step c is 0.03 mol / L; Preparation of ceramized glue: The vacuum degree of vacuum degassing is 80 Pa; Base material layer: glass fiber cloth (thickness 60 μm); Adhesive layer: acrylate pressure-sensitive adhesive (solid content 93%, peel strength 17 N / cm).

[0041] Preparation Example 5: Raw material composition (parts by weight): Organosilicon rubber matrix: 100 parts of vinyl-terminated methyl vinyl silicone rubber; Ceramic-forming filler (core-shell structure filler): 60 parts (the core of borosilicate glass has a particle size of 5 μm, Al 2 O 3 The thickness of the intermediate layer is 4 nm, and the thickness of the zirconia shell layer is 20 nm); Inorganic flame retardant filler: 30 parts of aluminum hydroxide (particle size 10 μm, modified with stearic acid); Crosslinking agent: 5 parts of dicumyl peroxide; Coupling agent: 2 parts of silane coupling agent KH560; The preparation steps are the same as those in Example 2: Preparation of core-shell filler: The reaction temperature in step b is 150°C, and the concentration of ethyl zirconate in step c is 0.3 mol / L; Preparation of ceramifiable glue: The shear rate is 100 s -1 and the viscosity at this time is 100 Pa·s; Base material layer: Aramid fiber cloth (thickness 90 μm); Adhesive layer: Organosilicon pressure-sensitive adhesive (solid content 98%, peel strength 22 N / cm).

[0042] Comparative example 1: Raw material composition (parts by weight): Organosilicon rubber matrix: 100 parts of methyl vinyl silicone rubber; Ordinary porcelain-forming filler: 45 parts (a simple physical mixture of 55 wt% borosilicate glass powder and 45 wt% nano-zirconia, the particle size of the glass powder is 1-5 μm, and the particle size of zirconia is 50-100 nm); Inorganic flame retardant filler: 20 parts of aluminum hydroxide (particle size 7 μm, modified with stearic acid); Crosslinking agent: 3 parts of dicumyl peroxide; Coupling agent: 1.25 parts of silane coupling agent KH550; The preparation steps are the same as those in Preparation example 1: Preparation of porcelain-forming filler: Directly mix borosilicate glass powder and nano-zirconia in proportion, and mechanically stir for 30 min (without core-shell coating process); Preparation of ceramifiable glue: The same as step t1 in Preparation example 1 (only the porcelain-forming filler is a physical mixture); Base material layer: Glass fiber cloth (thickness 75 μm); Adhesive layer: Organosilicon pressure-sensitive adhesive (the same as in Preparation example 1).

[0043] Comparative example 2: Raw material composition (parts by weight): Organosilicon rubber matrix: 100 parts of methyl vinyl silicone rubber; Core-shell structured filler (without Al 2 O 3 intermediate layer): 45 parts (the borosilicate glass core is directly coated with a zirconia shell layer, the shell layer thickness is 10 nm, and Al 2 O 3 is not deposited); Inorganic flame retardant filler: 20 parts of aluminum hydroxide (particle size 7 μm, modified with stearic acid); Crosslinking agent: 3 parts of dicumyl peroxide; Coupling agent: 1.25 parts of silane coupling agent KH550; Preparation steps: Preparation of core-shell filler: Step a: The same as in Example 1; Step b is omitted (without Al 2 O 3 intermediate layer deposition); Step c: directly add glass powder to the zirconium ethoxide hydrolysis solution, and other conditions are the same as in Example 1; Preparation of ceramizable glue and subsequent steps: the same as in Example 2.

[0044] Comparative Example 3: The ceramizable composite tape for fire prevention and high-temperature insulation of power batteries prepared by the invention patent with the application number 2022117146768.

[0045] Test Example 1: For Preparation Examples 1 - 5 and Comparative Examples 1 - 3, refer to ASTM C152 "Test Method for Thermal Shock Resistance of Ceramic Materials" and GB / T 30873 "Test Method for Thermal Shock Resistance of Inorganic Non-Metallic Materials" to test the thermal shock resistance (ΔT), refer to ASTM E1290 "Test Method for Crack Tip Opening Displacement (CTOD) of Metallic Materials" and GB / T 2358 "Test Method for Crack Tip Opening Displacement of Metallic Materials" to test the crack tip opening displacement (CTOD), refer to ASTM D256 "Test Method for Impact Strength of Plastics by the Cantilever Beam Method" and GB / T 1043.1 "Determination of Charpy Impact Properties of Plastics" to test the impact resistance, refer to ASTM E831 "Test Method for Coefficient of Linear Thermal Expansion of Materials" and GB / T 4339 "Measurement Method for Thermal Expansion Coefficient of Metallic Materials" to test the coefficient of thermal expansion (CTE), refer to ASTM D638 "Test Method for Tensile Properties of Plastics" and ISO 527-2 "Determination of Tensile Properties of Plastics - Part 2: High-Temperature Tests" to test the high-temperature toughness retention rate (800 °C). The test results are shown in Table 1 below: Table 1 From the comparison between Preparation Examples 1 - 5 and Comparative Examples 1 - 2, it can be seen that in Preparation Examples 1 - 5, a gradient thermal expansion matching is formed through the core-shell structure filler + Al 2 O 3 intermediate layer (CTE is between (3 - 12) × 10 -6 / °C), and ΔT is ≥ 550 °C in all cases, up to 700 °C at the highest, and can withstand the severe temperature fluctuations during fast charging / discharging of the battery pack (usually ≤ 600 °C). In Comparative Example 1 (ordinary filler), due to the direct physical mixing of borosilicate glass and zirconia, the interfacial thermal stress is concentrated, and ΔT is only 450 °C, lower than the requirements of the extreme working conditions of the battery pack; in Comparative Example 2 (without Al 2 O 3 layer), due to the sudden change in CTE (glass (3 - 5) × 10 -6 / °C → zirconia (10 - 12) × 10-6 / °C), ΔT drops to 500 °C, and interlayer cracking is likely to occur under thermal shock.

[0046] In Preparation Example, CTOD ≤ 0.40 mm and impact strength ≥ 10 kJ / m². Due to the interfacial toughening effect of the core-shell structure (the zirconia shell layer nanocrystals inhibit crack propagation, and the interface bonding force of the Al 2 O 3 intermediate layer reinforcing phase is enhanced), in Comparative Example 1, due to poor filler dispersion and weak interface bonding, CTOD increases by 57% and the impact strength decreases by 33%; in Comparative Example 2, due to the absence of the Al 2 O 3 transition layer, the interface bonding force decreases, CTOD increases by 37%, and the impact resistance performance only reaches the lower limit of the Preparation Example.

[0047] In the Preparation Example, CTE is controlled at (5.5 - 7.2)×10 -6 / °C, forming a reasonable gradient difference with the battery aluminum shell (CTE 23×10 -6 / °C), reducing the risk of interlayer peeling under high-temperature cycling; the toughness retention rate at 800 °C ≥ 68%, meeting the structural stability requirements for the long-term high-temperature service of the battery pack (usually ≤ 200 °C, but can reach 800 °C in the short term during thermal runaway). In the control group, CTE ≥ 8.5×10 -6 / °C, close to the CTE of the metal substrate, which is likely to cause interfacial stress concentration; the high-temperature toughness retention rate < 60%, unable to withstand the mechanical stress under extreme conditions.

[0048] From the comparison between Preparation Examples 1 - 5 and Comparative Example 3, it can be seen that the Preparation Examples are significantly superior to Comparative Example 3 in crack resistance, impact resistance, and high-temperature stability through the phase transformation toughening, interfacial energy absorption, and thermal expansion coordination effects of the core-shell structure fillers, especially in suppressing crack initiation and propagation and adapting to scenarios of drastic temperature changes.

[0049] In summary, Preparation Examples 1 - 5, through the three innovations of core-shell structure filler design, Al 2 O 3 gradient thermal expansion matching, and organic-inorganic interface synergistic enhancement, are significantly superior to the control group in key properties such as thermal shock resistance, impact strength, and high-temperature stability, fully meeting the stringent requirements of new energy vehicle power battery packs for ultra-high temperature resistance (≥ 550 °C thermal shock), high impact resistance (≥ 10 kJ / m²), and long life (high-temperature toughness retention rate ≥ 68%), and are ideal insulating and protective materials for power battery packs.

[0050] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles, characterized in that: include: A substrate layer, a ceramic tape layer and an adhesive layer stacked in sequence; The ceramic tape layer is formed by curing ceramic adhesive, and the ceramic adhesive comprises the following components in parts by weight: 100 parts of silicone rubber matrix; 30-60 parts of porcelain filler; 10-30 parts of inorganic flame retardant filler; 1-5 parts of cross-linking agent; Coupling agent 0.5-2 parts; The ceramic filler is a core-shell structure filler, which has borosilicate glass as the core and is coated with a nano-scale zirconium dioxide shell layer on the surface. The nano-scale zirconium dioxide particle size is 50-100nm and the coverage rate is ≥95%.

2. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 1, characterized in that: The silicone rubber matrix is ​​selected from at least one of methyl vinyl silicone rubber, vinyl-terminated methyl vinyl silicone rubber, and methyl vinyl MQ silicone resin; the inorganic flame retardant filler is selected from at least one of aluminum hydroxide and magnesium hydroxide; the cross-linking agent is selected from at least one of diisopropylbenzene peroxide and di-tert-butyl peroxide; and the coupling agent is selected from silane coupling KH550 or KH560.

3. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 1, characterized in that: The melting point of the borosilicate glass is 650±50° C., the chemical composition of the borosilicate glass is 55-65wt% SiO2, 15-25wt% B2O3, 5-15wt% Na2O, the impurity content is ≤1wt%, and the particle size is 1-5μm.

4. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 1, characterized in that: The particle size of the nano-scale zirconium dioxide shell layer is 50-100nm, the crystal form is tetragonal phase or monoclinic phase, it is stabilized by Y2O3, the shell layer thickness is 5-20nm, and the surface is grafted with a silane coupling agent after hydroxylation treatment.

5. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 3, characterized in that: The core-shell structure filler also includes Al2O3 in the middle layer. The thickness of the Al2O3 middle layer is 2-5nm and is prepared by atomic layer deposition. The Al2O3 coverage rate on the surface of the borosilicate glass core is ≥98%, which is used to match the difference in thermal expansion coefficients between borosilicate glass and zirconium dioxide.

6. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 5, characterized in that: The preparation method of the core-shell structure filler comprises the following steps: Step a, dispersing borosilicate glass powder in an ethanol-water solution with an ethanol-water volume ratio of 1:1 and a concentration of 50-100 g / L, ultrasonically dispersing for 30 min, filtering the dispersed borosilicate glass powder, washing with anhydrous ethanol 2-3 times, and vacuum drying at 60-80° C. to constant weight to ensure that the surface is dry; Step b, depositing an Al2O3 intermediate layer on the surface of the glass powder by atomic layer deposition, the reaction temperature is 100-150°C, the precursors are trimethylaluminum and deionized water, and the number of cycles is 50-100 times; Step c, adding the Al2O3 coated glass powder into 0.1-0.3 mol / L ethyl zirconate hydrolyzate, wherein the concentration of hydrochloric acid catalyst in the ethyl zirconate hydrolyzate is 0.01-0.05 mol / L, stirring at 60-80°C for 2-4h, filtering and drying to obtain a core-shell structure filler.

7. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 6, characterized in that: In step b, the thermal expansion coefficient of the Al2O3 intermediate layer is (8-10)×10 -6 / ℃, which is between the thermal expansion coefficient of borosilicate glass (3-5)×10 -6 / ℃ and the thermal expansion coefficient of zirconium dioxide (10-12) × 10 -6 / ℃, forming a gradient thermal expansion matching structure.

8. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 1, characterized in that: The mass ratio of the inorganic flame retardant filler to the core-shell structure filler is (1:1)-(1:3), the particle size of the inorganic flame retardant filler is 5-10 μm, and the surface is modified by stearic acid.

9. The ultra-high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to claim 1, characterized in that: The substrate layer is one of glass fiber cloth, aramid fiber cloth or basalt fiber cloth, with a thickness of 50-100 μm; the adhesive layer is silicone pressure-sensitive adhesive or acrylate pressure-sensitive adhesive, with a solid content of ≥90% and a peel strength of ≥15 N / cm.

10. A method for preparing a super high temperature resistant and impact resistant ceramic silicone composite belt for vehicles according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step t1, preparation of ceramic glue, premix the silicone rubber matrix for 10 minutes, vacuum degassing for 30 minutes, vacuum degree ≤ 100Pa, add core-shell filler, inorganic flame retardant filler, coupling agent in sequence, mix for 30 minutes until uniform dispersion, add cross-linking agent, continue mixing for 20 minutes to form a uniform paste ceramic glue, shear rate 100s -1 Viscosity 50-100 Pa·s; Step t2: pre-treating the substrate layer, cleaning the substrate, removing surface impurities and oil stains, and then performing surface activation treatment on the substrate; Step t3, coating the ceramic adhesive by scraping or rolling the ceramic adhesive evenly on the pretreated substrate layer to a thickness of 0.1-0.3 mm; Step t4, curing treatment, placing the substrate layer coated with the ceramic adhesive in an oven for curing treatment, the curing temperature is set to 120-150° C., the curing time is 1-2 hours, so that the ceramic adhesive is fully cured to form a ceramic tape layer; Step t5, adhesive layer compounding, the adhesive is evenly coated on the surface of the ceramic tape layer, the coating thickness is 0.02-0.05mm, the adhesive layer and the ceramic tape layer are tightly combined by rolling or laminating. After the compounding is completed, it is placed at room temperature for 24 hours to obtain an ultra-high temperature resistant and impact-resistant ceramic silicone composite tape for vehicles.

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