A super high temperature resistant and impact resistant ceramized silicone composite tape for vehicles and its preparation method

Abstract

The present invention relates to the technical field of the preparation of ceramized silica gel composite tapes for power batteries of new energy vehicles, and particularly relates to a super high temperature resistant and impact resistant ceramized silica gel composite tape for vehicles and a preparation method thereof. By using core-shell structure fillers to replace the original porcelain-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, a gradient structure design of the thermal expansion coefficient of the core-shell structure fillers is carried out to relieve the interfacial stress inside the core-shell structure fillers at high temperatures, avoid the generation of thermal stress concentration, improve the 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 the power battery from thermal runaway.

Description

Technical Field

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

[0002] A ceramized composite tape is a material that can quickly ceramize 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 buying time for personnel evacuation and fire fighting and rescue.

[0003] And 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, a ceramized composite tape for fire prevention and high temperature insulation of power batteries and its preparation and application are specifically disclosed, and it is realized that under the thickness of 0.15 - 0.5 mm, the flame retardant performance and ceramizable performance of the ceramized composite tape can still be ensured.

[0005] However, the use of glass micro powder, zinc borate, aluminum hydroxide, and magnesium hydroxide in the above-mentioned invention patent for the ceramized composite tape forms a "rigid particle filled brittle system", and cracks are easily initiated and rapidly propagated at the filler interface, resulting in a decrease in fracture toughness. At the same time, the inorganic filler (such as glass micro powder CTE≈(5 - 10)×10 -6 / ℃) and the silicone matrix (CTE≈(200 - 300)×10 -6 / ℃) have a large difference. When the temperature is high or changes suddenly, the matrix around the filler generates thermal stress concentration due to inconsistent shrinkage / expansion, and the thermal shock resistance fails, resulting in the initiation of microcracks. Especially when the power battery undergoes thermal runaway, 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 the flame retardant performance and ceramizable 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 - resistant and impact - resistant ceramized silicone composite tape and a preparation method thereof. By using a core - shell structure filler to replace the original porcelain - forming filler, the phase - change toughening effect of the core - shell structure filler usually generates compressive stress through the volume change during phase change, inhibits crack propagation, and improves fracture toughness. At the same time, a gradient structure design of the thermal expansion coefficient of the core - shell structure filler is carried out to relieve the interfacial stress inside the core - shell structure filler at high temperature, avoid the generation of thermal stress concentration, improve the 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 the power battery from thermal runaway.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A vehicle - used ultra - high temperature - resistant and impact - resistant ceramized silicone composite tape, comprising:

[0010] A base material layer, a ceramized tape layer, and an adhesive layer stacked in sequence;

[0011] The ceramized tape layer is formed by curing a ceramizing glue, and the ceramizing glue contains the following components in parts by weight:

[0012] 100 parts of an organosilicon rubber matrix;

[0013] 30 - 60 parts of a porcelain - forming filler;

[0014] 10 - 30 parts of an inorganic flame - retardant filler;

[0015] 1 - 5 parts of a cross - linker;

[0016] 0.5 - 2 parts of a coupling agent;

[0017] Among them, the porcelain - 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%.

[0018] 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.

[0019] 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 SiO2, 15 - 25 wt% of B2O3, 5 - 15 wt% of Na2O, the impurity content is ≤1 wt%, and the particle size is 1 - 5 μm.

[0020] As an improvement, the particle size of the nanoscale zirconia shell is 50 - 100 nm, the crystal form is tetragonal or monoclinic, it is stabilized by Y2O3 treatment, the shell thickness is 5 - 20 nm, and after surface hydroxylation treatment, a silane coupling agent is grafted.

[0021] The melting point of borosilicate glass (such as SiO2 - B2O3 - Na2O system) can be as low as 600 - 800 °C, and it quickly melts at high temperature to form a continuous glass phase, which serves as a "liquid bridge" for the ceramization reaction, promoting the diffusion and sintering of metal oxides (such as Al2O3, MgO). For example, at 600 °C, a dense ceramic shell can be formed on the borosilicate glass core within 30 seconds, with a significantly improved efficiency compared to traditional ceramization materials (which require several hours of heat preservation above 600 °C). At the same time, nanoscale zirconia (ZrO2) undergoes a tetragonal → 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 ZrO2.

[0022] 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 at the same time has good corrosion resistance, can resist the erosion of the ceramized layer by a humid and hot environment (such as 85 °C / 85%RH), with a volume resistivity decrease of ≤10% (30% for traditional materials). After the surface of nanoscale ZrO2 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.

[0023] As an improvement, the core - shell structure filler further includes Al2O3 in the intermediate layer, the thickness of the Al2O3 intermediate layer is 2 - 5 nm, which is prepared by atomic layer deposition, so that the Al2O3 coating rate on the surface of the borosilicate glass core is ≥98%, and it is used to match the difference in thermal expansion coefficients between borosilicate glass and zirconia.

[0024] It should be emphasized here that the thermal expansion coefficient of nanoscale ZrO2 (10×10 -6 / °C) is quite different from that of borosilicate glass (3.3×10 -6 / °C). During the high - temperature ceramization process, stress concentration will occur, resulting in a decrease in the interfacial bonding force between the core and the shell. To solve this problem, the present invention innovatively uses an Al2O3 intermediate layer to form an outer - layer nanoscale ZrO2 thermal expansion coefficient (10×10 -6 / °C), and the intermediate alumina thermal expansion coefficient ((7 - 8)×10 -6 / °C), the coefficient of thermal expansion of the internal borosilicate glass is (3.3×10 -6 A thermal expansion coefficient gradient buffer structure with a coefficient of thermal expansion of / °C) is used to eliminate the large difference in the coefficient of thermal expansion between nano-ZrO2 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 temperatures, while it drops to below 15 MPa after adding it. At the same time, the hydroxyl groups on the surface of alumina form hydrogen bonds with the silicon hydroxyl groups of the silicone rubber matrix, increasing the interfacial bonding strength 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.

[0025] Specifically, the core melts to absorb stress. The borosilicate glass melts at high temperatures and absorbs part of the thermal stress through plastic flow. The intermediate layer has a gradient transition. The coefficient of thermal expansion of the alumina intermediate layer is between that of the core and the shell, forming a stress gradient buffer zone. The shell undergoes phase transformation toughening. The phase transformation of nano-ZrO2 absorbs the energy for crack propagation, further suppressing stress concentration. Under the combined action, the thermal stress concentration coefficient of the composite material drops from 3.5 of traditional materials to 1.2, significantly improving the thermal shock resistance.

[0026] Furthermore, the melting of the core 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-ZrO2 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 traditional materials.

[0027] Regarding mechanical properties, the core provides rigid support. The borosilicate glass-ceramic layer provides high-temperature rigidity (Mohs hardness 5). The intermediate layer enhances toughness: the directional arrangement of 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: the phase transformation toughening of nano-ZrO2 increases the fracture toughness (KIC) of the ceramic layer from 2 MPa·m¹ / ² to 5 MPa·m¹ / ². The improvement of the comprehensive performance enables the volume resistivity of the composite material to drop by ≤10% after being placed in an 85 °C / 85%RH environment for 1000 hours (the traditional material drops by 30%).

[0028] As an improvement, the preparation method of the core-shell structure filler includes the following steps:

[0029] 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 2 - 3 times with absolute ethanol, 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 particle agglomeration caused by the too high surface tension of pure water;

[0030] Step b: Deposit 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. Trimethylaluminum is used as the aluminum source with high reaction activity, and the by - product of the reaction with water to form Al2O3 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 ALD cycle generates an Al2O3 layer with a thickness of about 0.1 - 0.2 nm, and 50 - 100 cycles can form a uniform coating with a thickness of 5 - 20 nm. As an 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 - layer ethyl zirconate. If it is too thick (>20 nm), it increases the filler density and raises the cost;

[0031] Step c: Add the Al2O3 - coated glass powder to an ethyl zirconate hydrolysis solution with a concentration of 0.1 - 0.3 mol / L, where 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 a core - shell structure filler. Specifically, ethyl zirconate (Zr(OC2H5)4) hydrolyzes and polycondenses to form a ZrO2 shell layer on the surface of the Al2O3 - coated glass powder through the sol - gel method. The reaction equation can be simplified as:

[0032] Hydrolysis: Zr(OC2H5)4 + 4H2O → Zr(OH)4 + 4C2H5OH

[0033] Polycondensation: nZr(OH)4 → (ZrO2) n + 2nH2O

[0034] The - OH groups of the Al2O3 intermediate layer form hydrogen bonds with the hydroxyl groups in the ZrO2 gel and are converted into chemical bonds (Al - O - Zr) after calcination, enhancing the core - shell interface bonding and avoiding shell layer shedding.

[0035] As an improvement, in step b, the thermal expansion coefficient of the Al2O3 intermediate layer is (8 - 10)×10 -6 / °C, 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.

[0036] 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.

[0037] 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 silicone pressure - sensitive adhesive or acrylate pressure - sensitive adhesive, with a solid content ≥90% and a peel strength ≥15 N / cm.

[0038] In addition, the present invention also provides a method for preparing a vehicle - used ultra - high temperature and impact - resistant ceramized silica gel composite tape as described in any one of the above, comprising the following steps:

[0039] Step t1, preparation of ceramized glue: Premix the silicone rubber matrix for 10 min, degas it under vacuum for 30 min with a vacuum degree ≤100 Pa, successively add core - shell filler, inorganic flame retardant filler, coupling agent, and knead for 30 min until evenly dispersed. Then add a cross - linker and continue kneading for 20 min to form a uniform paste - like ceramized glue, with a viscosity of 50 - 100 Pa·s at a shear rate of 100 s -1 ;

[0040] Step t2, pretreatment of the substrate layer: Clean the substrate to remove surface impurities and oil, and then perform surface activation treatment on the substrate;

[0041] Step t3, coating the ceramized glue: Adopt the scraping or roller coating method to evenly coat the ceramized glue on the pretreated substrate layer, with a thickness of 0.1 - 0.3 mm;

[0042] Step t4, curing treatment: Put the substrate layer coated with ceramized 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 ceramized glue to form a ceramized tape layer;

[0043] 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 closely combine with the ceramized tape layer. After the composite is completed, place it at room temperature for 24 h to obtain a vehicle - used ultra - high temperature and impact - resistant ceramized silica gel composite tape.

[0044] The beneficial effects of the present invention are as follows:

[0045] (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℃), the surface is coated with a nano-scale zirconium dioxide shell layer (particle size 50-100nm), and an Al2O3 intermediate layer (thickness 2-5nm) is used to achieve a gradient matching of the thermal expansion coefficient (borosilicate glass (3-5)×10 -6 / ℃→Al2O3(8-10)×10 -6 / ℃→Zirconium dioxide (10-12)×10 -6 / ℃), this structure can form a dense ceramic layer under high temperature environment, effectively resisting thermal shock. At the same time, the high-strength nanocrystalline structure of shell zirconium dioxide (tetragonal or monoclinic phase, stabilized by Y2O3) significantly improves the impact resistance of the composite tape, avoiding cracking and failure caused by sudden temperature change or mechanical stress;

[0046] (2) The present invention has high-efficiency flame retardant and environmentally friendly properties. The inorganic flame retardant filler (aluminum hydroxide, magnesium hydroxide) and the core-shell structure filler are compounded in a mass ratio of (1:1)-(1:3), and the filler surface 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 filler releases crystal water to absorb heat and cool down, the borosilicate glass melts to form an insulating layer, and the zirconium dioxide shell layer maintains the ceramic skeleton structure. The three work synergistically to achieve halogen-free flame retardancy, excellent flame retardant performance and meet environmental protection requirements, and are suitable for high-safety automotive scenarios;

[0047] (3) The present invention has excellent interfacial compatibility and mechanical stability. The surface of the core-shell filler is treated with hydroxylation and grafted with a silane coupling agent (KH550 or KH560) to form a chemical bond with the silicone rubber matrix. Combined with the Al2O3 intermediate layer prepared by atomic layer deposition (coverage rate ≥ 98%), the interfacial compatibility between the filler and the matrix is effectively improved, and stress concentration is reduced. The cross-linking agent (diisopropylbenzene peroxide, etc.) promotes the matrix to form a three-dimensional network structure. Combined with a high-strength substrate such as glass fiber cloth (thickness 50-100μm), the composite tape has both high tensile strength and flexibility, and is not easy to delaminate or break after long-term use;

[0048] (4) The present invention has good practical processability and adaptability. The substrate layer is made of high-temperature resistant fiber materials such as glass fiber cloth and aramid fiber cloth, and the adhesive layer is made of silicone pressure-sensitive adhesive or acrylic pressure-sensitive adhesive (solid content ≥ 90%, peel strength ≥ 15N / cm), which not only meets the bonding stability in high-temperature environment, but also facilitates construction and bonding. The surface activation treatment and roller coating / scrape coating process in the preparation process ensure that the layers are tightly bonded, which is suitable for industrial continuous production.

[0049] 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 technical field of ceramized silicone rubber for new energy vehicle power batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic flow chart of the preparation method of the core-shell structure filler in Embodiment 1 of the present invention;

[0051] Figure 2 It is a schematic flow chart of the preparation method of the vehicle-used ultra-high temperature resistant and impact resistant ceramized silicone rubber composite tape in Embodiment 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0052] 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.

[0053] The following will describe in detail 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.

[0054] All publications, patent applications, patents and other references mentioned in this specification are hereby incorporated by reference. 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.

[0055] When this specification uses prefixes such as "well-known to those skilled in the art", "prior art" or similar terms to derive materials, substances, methods, steps, devices or components, etc., the objects derived by these 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 commonly recognized in the art as suitable for similar purposes.

[0056] 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 (such as methods or systems) formed thereby belong to a part of the original disclosure content of this specification and also fall within the protection scope of the present invention.

[0057] 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.

[0058] Example 1:

[0059] As Figure 1 shown, the preparation method of the core-shell structure filler comprises the following steps:

[0060] 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;

[0061] Step b: Deposit 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. 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;

[0062] Step c: Add the glass powder coated with Al2O3 to an ethyl zirconate hydrolysis solution with a concentration of 0.1-0.3 mol / L, where 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, and obtain the core-shell structure filler after filtration and drying.

[0063] 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.

[0064] Example 2:

[0065] As Figure 2 shown, a method for preparing a vehicle-use ultra-high temperature resistant and impact-resistant ceramized silica gel composite tape comprises the following steps:

[0066] Step t1: Preparation of ceramizing glue. Premix the organosilicon rubber matrix for 10 min, vacuum degas for 30 min with a vacuum degree ≤ 100 Pa, sequentially add the core-shell filler, inorganic flame retardant filler, and coupling agent, mix for 30 min until evenly dispersed, add the crosslinking 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 ;

[0067] 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;

[0068] Step t3: Coating the ceramizing glue. Adopt a scraping or roll coating method to evenly coat the ceramizing glue on the pretreated base material layer with a thickness of 0.1-0.3 mm;

[0069] Step t4, curing treatment: Put the substrate layer coated with the ceramizable glue into an oven for curing treatment. The curing temperature is set at 120 - 150 °C, and the curing time is 1 - 2 h to fully cure the ceramizable glue to form a ceramizable tape layer;

[0070] Step t5, adhesive layer lamination: Uniformly coat the adhesive on the surface of the ceramizable tape layer with a coating thickness of 0.02 - 0.05 mm. Through the method of roll pressing or laminating, make the adhesive layer tightly combine with the ceramizable tape layer. After lamination, place it at room temperature for 24 h to obtain a super high temperature resistant and impact resistant ceramizable silicone composite tape for vehicles.

[0071] 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.

[0072] Preparation Example 1:

[0073] Raw material composition (parts by weight):

[0074] Organosilicon rubber matrix: 100 parts of methyl vinyl silicone rubber;

[0075] Ceramic - forming filler (core - shell structure filler): 45 parts (borosilicate glass core melting point 650 °C, Al2O3 intermediate layer thickness 3 nm, zirconia shell layer thickness 10 nm);

[0076] Inorganic flame - retardant filler: 20 parts of aluminum hydroxide (particle size 7 μm, modified with stearic acid);

[0077] Cross - linker: 3 parts of dicumyl peroxide;

[0078] Coupling agent: 1.25 parts of silane coupling agent KH550;

[0079] The preparation steps are the same as those in Example 2:

[0080] Preparation of core - shell filler: The number of cycles of step b is 75 times, and the hydrolysis temperature and time in step c are 70 °C and 3 h respectively;

[0081] Preparation of ceramizable glue: The viscosity at a shear rate of 100 s -1 is 75 Pa·s;

[0082] Substrate layer: Fiberglass cloth (thickness 75 μm);

[0083] Adhesive layer: Organosilicon pressure - sensitive adhesive (solid content 95%, peel strength 18 N / cm).

[0084] Preparation Example 2:

[0085] Raw material composition (parts by weight):

[0086] Silicone rubber matrix: 100 parts of vinyl-terminated methyl vinyl silicone rubber;

[0087] Porcelain-forming filler (core-shell structure filler): 30 parts (borosilicate glass core particle size 1 μm, Al2O3 intermediate layer thickness 2 nm, zirconia shell layer thickness 5 nm);

[0088] Inorganic flame retardant filler: 10 parts of magnesium hydroxide (particle size 5 μm, modified with stearic acid);

[0089] Crosslinking agent: 1 part of di-tert-butyl peroxide;

[0090] Coupling agent: 0.5 part of silane coupling agent KH560;

[0091] The preparation steps are the same as those in Example 2:

[0092] Preparation of core-shell filler: The number of cycles of step b is 50 times, and the hydrolysis temperature in step c is 60 °C and the time is 2 h;

[0093] Preparation of ceramizable glue: The viscosity at a shear rate of 100 s -1 is 50 Pa·s;

[0094] Base material layer: Aramid fiber cloth (thickness 50 μm);

[0095] Adhesive layer: Acrylate pressure-sensitive adhesive (solid content 90%, peel strength 15 N / cm).

[0096] Preparation Example 3:

[0097] Raw material composition (parts by weight):

[0098] Silicone rubber matrix: 100 parts of methyl vinyl MQ silicone resin;

[0099] Porcelain-forming filler (core-shell structure filler): 50 parts (Al2O3 intermediate layer thickness 5 nm, zirconia shell layer particle size 80 nm);

[0100] Inorganic flame retardant filler: 15 parts of aluminum hydroxide (particle size 10 μm, modified with stearic acid);

[0101] Crosslinking agent: 4 parts of diisopropylbenzene peroxide;

[0102] Coupling agent: 1.5 parts of silane coupling agent KH550;

[0103] The preparation steps are the same as those in Example 2:

[0104] Preparation of core-shell filler: The number of cycles of step b is 100 times, and the hydrolysis temperature in step c is 80 °C and the time is 4 h;

[0105] Preparation of ceramifiable adhesive: Viscosity is 85 Pa·s at a shear rate of 100 s -1 ;

[0106] Base material layer: Basalt fiber cloth (thickness 100 μm);

[0107] Adhesive layer: Organosilicon pressure-sensitive adhesive (solid content 92%, peel strength 20 N / cm).

[0108] Preparation Example 4:

[0109] Raw material composition (parts by weight):

[0110] Organosilicon rubber matrix: 70 parts of methyl vinyl silicone rubber + 30 parts of methyl vinyl MQ silicone resin;

[0111] 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);

[0112] Inorganic flame retardant filler: 25 parts of magnesium hydroxide (particle size 8 μm, modified with stearic acid);

[0113] Crosslinking agent: 2 parts of di-tert-butyl peroxide;

[0114] Coupling agent: 2 parts of silane coupling agent KH550;

[0115] The preparation steps are the same as those in Example 2:

[0116] Preparation of core-shell filler: The pulse time of trimethylaluminum precursor in step b is 1 s, and the concentration of hydrochloric acid catalyst in step c is 0.03 mol / L;

[0117] Preparation of ceramifiable adhesive: The vacuum degree for vacuum degassing is 80 Pa;

[0118] Base material layer: Glass fiber cloth (thickness 60 μm);

[0119] Adhesive layer: Acrylate pressure-sensitive adhesive (solid content 93%, peel strength 17 N / cm).

[0120] Preparation Example 5:

[0121] Raw material composition (parts by weight):

[0122] Organosilicon rubber matrix: 100 parts of vinyl-terminated methyl vinyl silicone rubber;

[0123] Ceramic-forming filler (core-shell structure filler): 60 parts (borosilicate glass core particle size 5 μm, Al2O3 intermediate layer thickness 4 nm, zirconia shell layer thickness 20 nm);

[0124] Inorganic flame retardant filler: 30 parts of aluminum hydroxide (particle size 10 μm, modified with stearic acid);

[0125] Crosslinking agent: 5 parts of dicumyl peroxide;

[0126] Coupling agent: 2 parts of silane coupling agent KH560;

[0127] The preparation steps are the same as those in Example 2:

[0128] 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;

[0129] Preparation of ceramized glue: The viscosity at a shear rate of 100 s -1 is 100 Pa·s;

[0130] Base material layer: aramid fiber cloth (thickness 90 μm);

[0131] Adhesive layer: silicone pressure-sensitive adhesive (solid content 98%, peel strength 22 N / cm).

[0132] Comparative Example 1:

[0133] Raw material composition (parts by weight):

[0134] Organic silicone rubber matrix: 100 parts of methyl vinyl silicone rubber;

[0135] Ordinary ceramic-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);

[0136] Inorganic flame retardant filler: 20 parts of aluminum hydroxide (particle size 7 μm, modified with stearic acid);

[0137] Crosslinking agent: 3 parts of dicumyl peroxide;

[0138] Coupling agent: 1.25 parts of silane coupling agent KH550;

[0139] The preparation steps are the same as those in Preparation Example 1:

[0140] Preparation of ceramic-forming filler: Directly mix borosilicate glass powder and nano-zirconia in proportion and mechanically stir for 30 min (without core-shell coating process);

[0141] Preparation of ceramized glue: The same as step t1 in Preparation Example 1 (only the ceramic-forming filler is a physical mixture);

[0142] Base material layer: glass fiber cloth (thickness 75 μm);

[0143] Adhesive layer: silicone pressure-sensitive adhesive (the same as in Preparation Example 1).

[0144] Comparative Example 2:

[0145] Raw material composition (parts by weight):

[0146] Silicone rubber matrix: 100 parts of methyl vinyl silicone rubber;

[0147] Core-shell structure filler (without Al2O3 intermediate layer): 45 parts (borosilicate glass core directly coated with zirconia shell layer, shell layer thickness 10 nm, no Al2O3 deposited);

[0148] Inorganic flame retardant filler: 20 parts of aluminum hydroxide (particle size 7 μm, modified with stearic acid);

[0149] Crosslinking agent: 3 parts of dicumyl peroxide;

[0150] Coupling agent: 1.25 parts of silane coupling agent KH550;

[0151] Preparation steps:

[0152] Preparation of core-shell filler:

[0153] Step a: The same as Example 1;

[0154] Omit step b (no Al2O3 intermediate layer deposition);

[0155] Step c: Directly add glass powder to the zirconium ethoxide hydrolysis solution, and other conditions are the same as in Example 1;

[0156] Preparation of ceramizable glue and subsequent steps: The same as Example 2.

[0157] Comparative Example 3:

[0158] Ceramizable composite tape for fire prevention and high-temperature insulation of power batteries prepared by the invention patent with the application number 2022117146768.

[0159] Test Example 1:

[0160] For Preparation Examples 1 - 5 and Comparative Examples 1 - 3, the thermal shock resistance (ΔT) was tested with reference to ASTM C152 "Test Method for Thermal Shock Resistance of Ceramic Materials" and GB / T 30873 "Test Method for Thermal Shock Resistance of Inorganic Nonmetallic Materials", the crack tip opening displacement (CTOD) was tested with reference 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", the impact strength was tested with reference to ASTM D256 "Test Method for Impact Resistance of Plastics by the Cantilever Beam Method" and GB / T 1043.1 "Determination of Charpy Impact Strength of Plastics", and the coefficient of thermal expansion (CTE) was tested with reference to ASTM E831 "Test Method for Coefficient of Linear Thermal Expansion of Materials" and GB / T 4339 "Method for Measuring Coefficient of Thermal Expansion of Metallic Materials". The high-temperature toughness retention rate (800 °C) was tested with reference 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". The test results are shown in Table 1 below:

[0161] Table 1

[0162]

[0163] From the comparison between Preparation Examples 1 - 5 and Comparative Examples 1 - 2, it can be seen that Preparation Examples 1 - 5 form a gradient thermal expansion matching (CTE between (3 - 12)×10 -6 / °C) through the core-shell structure filler + Al2O3 intermediate layer, and ΔT is ≥550 °C, reaching up to 700 °C at most, and can withstand the severe temperature fluctuations during the fast charging / discharging of the battery pack (usually ≤600 °C).

[0164] 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 Al2O3 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.

[0165] For the preparation examples, CTOD ≤ 0.40 mm and the impact strength ≥ 10 kJ / m². Due to the interfacial toughening effect of the core-shell structure (the nanocrystals in the zirconia shell layer inhibit crack propagation, and the Al2O3 intermediate layer enhances the interfacial bonding force), in Comparative Example 1, due to poor filler dispersion and weak interfacial bonding, CTOD increases by 57% and the impact strength decreases by 33%; in Comparative Example 2, due to the absence of the Al2O3 transition layer, the interfacial bonding force decreases, CTOD increases by 37%, and the impact performance only reaches the lower limit of the preparation examples.

[0166] The preparation example has the CTE controlled within (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 delamination under high-temperature cycling; the toughness retention rate at 800°C is ≥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). For the control group, CTE≥8.5×10 -6 / °C, which is close to the CTE of the metal substrate, easily leading to interfacial stress concentration; the high-temperature toughness retention rate is <60%, unable to withstand the mechanical stress under extreme conditions.

[0167] 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 terms of crack resistance, impact resistance, and high-temperature stability through the phase change toughening, interfacial energy absorption, and thermal expansion coordination effects of the core-shell structure fillers, especially showing outstanding advantages in suppressing crack initiation and propagation and adapting to scenarios of drastic temperature changes.

[0168] In summary, Preparation Examples 1 - 5 are significantly superior to the control group in key properties such as thermal shock resistance, impact strength, and high-temperature stability through three innovations: core-shell structure filler design, Al2O3 gradient thermal expansion matching, and organic-inorganic interface synergistic enhancement, 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.

[0169] 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vehicle - used ultra - high temperature - resistant and impact - resistant ceramized silicone composite tape, characterized in that, Including: 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 silicone rubber matrix; 30 - 60 parts of porcelain-forming filler; 10 - 30 parts of inorganic flame retardant filler; 1 - 5 parts of cross-linking agent; 0.5 - 2 parts of coupling agent; Among them, 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 porcelain-forming filler is a core-shell structure filler. This core-shell structure filler has a borosilicate glass as the core, and a nanoscale zirconia shell layer is coated on the surface. The particle size of the nanoscale zirconia is 50 - 100 nm, and the coating rate is ≥95%. The core-shell structure filler also includes Al2O3 in the middle layer. The thickness of the Al2O3 middle layer is 2 - 5 nm, which is prepared by atomic layer deposition to make the Al2O3 coating rate on the surface of the borosilicate glass core ≥98% for matching the difference in thermal expansion coefficients between the borosilicate glass and zirconia; The preparation method of the core-shell structure filler includes the following steps: Step a: Disperse the 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; Step b: Deposit the Al2O3 middle layer on the glass powder surface 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: Add the glass powder coated with Al2O3 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.

2. The ultra-high temperature resistant and impact resistant ceramizable silica gel composite tape for vehicles according to claim 1, wherein: 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 dicumyl peroxide and di-tert-butyl peroxide. The coupling agent is selected from silane coupling agent KH550 or KH560.

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

4. The ultra-high temperature resistant and impact resistant ceramizable silica gel composite tape for vehicles according to claim 1, wherein: The particle size of the nanoscale zirconia shell layer is 50 - 100 nm, the crystal form is tetragonal or monoclinic, it is stabilized by Y2O3, the shell layer thickness is 5 - 20 nm, and a silane coupling agent is grafted after surface hydroxylation treatment.

5. A super high temperature resistant and impact resistant ceramizable silicone composite tape for vehicles according to claim 1, wherein: In step b, the thermal expansion coefficient of the Al2O3 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.

6. A super high temperature resistant and impact resistant ceramizable silicone composite tape for vehicles according to claim 1, wherein: 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.

7. A super high temperature resistant and impact resistant ceramizable silicone composite tape for vehicles according to claim 1, wherein: 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 silicone pressure-sensitive adhesive or acrylate pressure-sensitive adhesive, with a solid content ≥ 90% and a peel strength ≥ 15 N / cm.

8. A method for preparing a vehicle - used ultra - high temperature - resistant and impact - resistant ceramized silica gel composite tape according to any one of claims 1 - 7, characterized in that, It includes the following steps: Step t1: Preparation of ceramizable glue. Premix the silicone 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 crosslinking agent and continue kneading for 20 min to form a uniform paste-like ceramizable glue with a shear rate of 100 s -1 and a viscosity of 50 - 100 Pa·s at this time; Step t2, pretreatment of the substrate layer. After cleaning the substrate to remove surface impurities and oil stains, surface activation treatment is carried out on the substrate. Step t3, coating the ceramizable glue. The ceramizable glue is evenly coated on the pretreated substrate layer by scraping or rolling, with a thickness of 0.1-0.3 mm. Step t4, curing treatment. The substrate layer coated with the ceramizable glue is placed in an oven for curing treatment. The curing temperature is set at 120-150 °C, and the curing time is 1-2 h, so that the ceramizable glue is fully cured to form a ceramizable tape layer. Step t5, composite of the adhesive layer. The adhesive is evenly coated on the surface of the ceramizable tape layer, with a coating thickness of 0.02-0.05 mm. By rolling or laminating, the adhesive layer is tightly combined with the ceramizable tape layer. After the composite is completed, it is placed at room temperature for 24 h to obtain a super high temperature resistant and impact resistant ceramizable silicone composite tape for vehicles.

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