Multifunctional ceramic composite material for thermal runaway safety protection of battery pack and preparation method of multifunctional ceramic composite material

Abstract

The invention provides a multifunctional composite material for thermal runaway global protection of a power battery system and a preparation method of the multifunctional composite material, and belongs to the technical field of new energy safety materials. The composite material is formed by compounding a surface-metalized glass fiber reinforcement layer and a ceramic glass fiber composite material matrix through an integrated molding process, a metal organic framework material is uniformly dispersed in the ceramic glass fiber composite material matrix. According to the invention, a single material system can cope with multiple security threats such as high-temperature flame, toxic smog, electromagnetic interference and mechanical shock generated in the thermal runaway process at the same time. The surface-modified MOF material simultaneously plays dual functions of suppressing smoke, reducing toxicity and enhancing an interface in a system, and has a synergistic effect with a fiber layer of the conductive glass fiber cloth, so that the structural integrity and functionality of the material in an extreme environment are ensured. The material is particularly suitable for safety protection between power battery modules, and solves the problems of poor reliability, large volume, large weight, high cost and the like in the traditional stacked solution.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and particularly to a multifunctional integrated material for thermal runaway protection in new energy battery packs. Specifically, it is a composite ceramicized silicone rubber foam material and its preparation method that combine electromagnetic shielding, ultra-high temperature fire resistance, smoke suppression and detoxification, and high reliable interfacial strength. In particular, it is a multifunctional ceramicized composite material based on metal-organic framework material modification. Background Technology

[0002] With the rapid development of new energy, aerospace, and other fields, the demand for high-performance protective materials is becoming increasingly urgent. Especially in power battery systems, thermal runaway events can trigger multiple safety hazards: high temperatures from severe mechanical impacts (reaching over 1000℃), the generation of large amounts of toxic fumes, and intense electromagnetic pulses. Currently, the industry commonly adopts a "stacked" solution, using separate metal shielding layers, fireproof and heat-insulating layers, and structural support layers to address different safety threats. This solution has inherent drawbacks such as system complexity, large weight, large space occupation, and poor reliability of the interfaces between layers, and is prone to delamination failure under extreme conditions.

[0003] As a new type of fireproof material, ceramicized glass fiber composite material can form a ceramic protective layer at high temperatures, providing certain fire resistance. However, existing ceramicized glass fiber composite materials still have the following shortcomings: (1) the ceramic body formed at high temperatures has low strength and is prone to cracking and pulverization; (2) it cannot effectively suppress the toxic fumes generated during combustion; (3) it lacks electromagnetic protection function; (4) the interfacial bonding strength with the reinforcing material is insufficient, and it is prone to delamination under thermal shock conditions.

[0004] Metal-organic frameworks (MOFs) are novel porous polymers formed by the coordination of metal ions and organic ligands. They possess characteristics such as large specific surface area, high pore density, and tunable chemical structure, and are widely used in gas adsorption, batteries, and flame retardancy. By combining the unique properties of MOF materials with the fire-resistant properties of ceramicized glass fiber composites, a multifunctional, integrated, lightweight composite material has been developed to meet the stringent requirements for safety, material strength, and electromagnetic shielding compatibility in battery pack thermal runaway scenarios. Summary of the Invention

[0005] (a) Purpose of the invention: This invention addresses the specific safety requirements of thermal runaway protection in power battery systems by providing a multifunctional composite material and its preparation method that integrates fire resistance, smoke suppression, electromagnetic shielding, and interface reinforcement. The purpose of this invention is to solve the problems of poor reliability, heavy weight, and high cost associated with current "stacked" solutions. It provides a composite material for battery systems that integrates electromagnetic shielding, ultra-high temperature fire resistance, smoke suppression and toxicity reduction, and high interface reliability. Through materials science innovation, it fundamentally simplifies battery pack safety design and improves its intrinsic safety level.

[0006] (II) Technical Solution To achieve the above objectives, the present invention adopts the following technical solution: a multifunctional composite material for thermal runaway protection of power battery systems. Its innovation lies in achieving multifunctional integration through the multi-component synergistic design of the material system. The material includes a ceramicized glass fiber composite matrix layer and a reinforcing layer, wherein the ceramicized glass fiber composite matrix layer contains a specific proportion of metal-organic framework material. Using ceramicized silicone rubber foam as the matrix, it provides basic fire-resistant functions such as flexibility, cushioning, and ceramicization upon contact with fire.

[0007] A multifunctional ceramicized composite material for thermal runaway safety protection of battery packs has a layered composite structure, including a smoke-suppressing ceramicized silicone layer, a glass fiber matrix reinforcement layer, and a metal shielding layer composited on the surface of the glass fiber matrix reinforcement layer. The thickness of the glass fiber reinforcement layer is 0.05-0.2 mm, and the thickness of the metal coating layer is 5-10 μm.

[0008] The ceramicizable silicone layer of the ceramicized glass fiber composite material is formed by vulcanization and cross-linking curing of raw materials comprising the following parts by weight: 10-30 parts of COF material surface-modified metal-organic framework (MOF) dry powder, 10-30 parts of aluminum hydroxide powder, 10-45 parts of composite ceramic powder, 5-15 parts of low-melting-point glass powder, 10-15 parts of methyl vinyl silicone rubber with a viscosity of 60,000-80,000 Pa·s, 15-35 parts of vinyl silicone oil with a viscosity of 1,000-2,000 Pa·s, 15-35 parts of hydroxyl silicone oil with a viscosity of 30-50 Pa·s, 5-15 parts of hydrogen-containing silicone oil, 1-2 parts of platinum catalyst, and 1-3 parts of inhibitor.

[0009] The metal-organic framework (MOF) dry powder includes at least one of NH2-MIL-125(Ti), NH2-MIL-68(In), or NH2-UiO-66.

[0010] The surface-modified metal-organic framework (MOF) dry powder is produced by reacting a Schiff base with a core coated with a COF material as the shell. The surface-modified COF material includes at least one of TpPa-1, TpBD, or TpAz.

[0011] The surface modification reaction of the COF-modified MOF is a Schiff base reaction. The specific preparation method is as follows: TpAz and NH2-MIL-68(In) powders are dispersed stepwise in a mesitylene solution, and an interfacial reaction is carried out under acidic catalytic conditions and heated to 120°C. The -NH2 on the MOF surface preferentially reacts with the -CHO of the Tp monomer in the solution to form an imine bond (-C=N-). These covalent bonds firmly anchor the COF to the MOF surface, serving as nucleation sites and inducing the Tp and Az monomers to continue polymerizing and growing on it, ultimately forming a complete COF shell on the MOF. After centrifugation and drying, the TpAz-modified NH2-MIL-68(In) is obtained, i.e., NH2-MIL-68(In)@TpAz.

[0012] The same method was used to prepare surface-modified NH2-MIL-125(Ti) and surface-modified NH2-UiO-66. Surface modification can also be selected from TpPa-1 or TpBD.

[0013] This yields NH2-MIL-68(In)@TpPa-1, NH2-MIL-68(In)@TpBD, NH2-MIL-125(Ti)@TpAz, NH2-MIL-125(Ti)@TpPa-1, NH2-MIL-125(Ti)@TpBD, NH2-UiO-66@TpAz, NH2-UiO-66@TpPa-1, and NH2-UiO-66@TpBD.

[0014] The metal glass fiber reinforcement layer is a glass fiber cloth with a metallized coating on its surface; the metallized coating is a chemically plated nickel layer or an electroplated nickel layer with a thickness of 0.5-10 micrometers; the thickness of the glass fiber cloth is 0.05-0.2 millimeters; the glass fiber reinforcement layer is a glass fiber cloth, and its main component is SiO2.

[0015] The composite ceramic powder is a mixture of two or more of diatomaceous earth, wollastonite, zirconium oxide, kaolin, mica powder and talc powder; the low melting point glass powder is a phosphate-based or borosilicate-based glass powder with a softening point temperature of 450-550℃.

[0016] The inhibitor is ethynylcyclohexanol or maleate ester compounds.

[0017] After being burned in a flame at 800-1000℃ for 10-30 minutes, the material's remains retain structural integrity and show no delamination or pulverization.

[0018] The material has an electromagnetic shielding effectiveness of not less than 35 dB in the 1-10 GHz frequency range.

[0019] The smoke density rating (SDR) of the material during combustion does not exceed 40, and the carbon monoxide (CO) yield does not exceed 15 mg / g; the interfacial peel strength between the ceramicized glass fiber composite matrix layer and the glass fiber reinforcement layer is not less than 2.0 N / mm.

[0020] A method for preparing a multifunctional ceramicized composite material includes the following steps: (1) Preparation of rubber compound: Methyl vinyl silicone rubber, vinyl silicone oil, hydroxyl silicone oil, hydrogen-containing silicone oil, inhibitor and platinum catalyst are mixed evenly under a closed and moisture-proof condition. Then aluminum hydroxide, composite ceramic powder, low melting point glass powder and MOF material are added and stirred at high speed until evenly dispersed to obtain ceramicized rubber compound. (2) First vulcanization and coating: The ceramicized adhesive is coated on the release paper and vulcanized for the first time at 120-150℃ for 10-20 minutes; (3) Reinforcing layer bonding and second vulcanization: On the surface of the rubber layer after the first vulcanization, the surface metallized glass fiber cloth reinforcing layer is bonded to it by a pressure roller to form a preform; then the preform is vulcanized for the second time at 160-200℃ for 1-2 hours. (4) Post-processing: After vulcanization, the composite material is obtained by cooling and cutting.

[0021] The multifunctional composite material is used in power battery modules or battery packs as an integrated safety barrier material for one or more of the following: fireproofing, heat insulation, smoke suppression, or electromagnetic shielding.

[0022] The metallized conductive glass fiber cloth is used in combination with it. This layer has three benefits: (1) the metal layer provides electromagnetic shielding at room temperature; (2) the glass fiber cloth serves as a high-temperature reinforcing skeleton to prevent the ceramic body from cracking; (3) the two together constitute the main structure of the material. The reinforcing layer uses surface-metallized glass fiber cloth, which not only provides mechanical reinforcement, but also forms a composite ceramic-metal network structure with the ceramicized layer at high temperature, maintaining structural integrity and electromagnetic shielding function.

[0023] The role of the metal-organic framework (MOF) material in the system: Multifunctional Synergist: A novel approach involves introducing modified MOF materials into a silicone rubber matrix. This is crucial for achieving functional integration and synergy. The MOF performs three functions in this system: Core features for smoke suppression and toxicity reduction: Utilizing its large specific surface area, it adsorbs smoke particles and catalytically decomposes toxic gases. Interface enhancement anchor points: Its micro-wrinkled surface structure and abundant surface functional groups form a "micro-mechanical interlock" at the interface between silicone and glass fiber cloth, significantly improving interlayer bonding and eliminating the risk of delamination.

[0024] Gas-phase flame retardant synergist: It catalyzes and captures combustion free radicals in porous channels, forming a gas-solid synergistic flame retardant mechanism with the solid-phase ceramic layer.

[0025] This invention also provides the application of a multifunctional composite material in the power battery module or battery pack layer as an integrated safety barrier material for one or more of the following: fireproofing, heat insulation, smoke suppression, or electromagnetic shielding.

[0026] (III) Beneficial Effects Compared with existing technologies, this invention is the first to simultaneously solve the problem of full-domain safety protection against thermal runaway in a single material system. Compared with existing technologies, this invention has the following outstanding advantages: Integrated Functionality: A single material simultaneously provides multiple functions such as fire prevention, smoke suppression, electromagnetic shielding, and interface enhancement, perfectly addressing the multiple safety threats of battery thermal runaway. It overturns the traditional "stacked" design, achieving lightweight, thinness, and high reliability.

[0027] Synergistic effect: The components do not work independently. In particular, the introduction of MOF solves three major problems at the same time: smoke suppression, interface and synergistic flame retardancy. The effect is far better than adding conventional additives.

[0028] Safety across all operating conditions: From normal conditions (electromagnetic shielding) to disaster conditions (fire resistance, smoke suppression), and then to harsh environments (high heat resistance, anti-delamination), it provides continuous safety assurance.

[0029] Interface reliability: The unique interface design ensures the structural integrity of the material under thermal shock conditions, avoiding delamination. Its robust ceramic-glass fiber-MOF composite remnant formed upon exposure to fire provides a fire barrier for over 40 minutes.

[0030] Applicability: The material design is specifically tailored for power battery thermal runaway scenarios, solving the technical challenges in this particular application area. Detailed Implementation

[0031] The present invention will be described in detail below through examples.

[0032] Example 1 A multifunctional ceramic composite material for thermal runaway safety protection of battery packs and its preparation method.

[0033] Step 1: Rubber compound raw materials: 10 parts 60000-80000 Pa·s methyl vinyl silicone rubber, 20 parts 1000~2000 Pa·s vinyl silicone oil, 20 parts 30-50 Pa·s hydroxyl silicone oil, 8 parts hydrogen-containing silicone oil, 1.5 parts platinum catalyst and 3 parts inhibitor ethynylcyclohexanol; Ceramic filler: 30 parts composite ceramic powder (wollastonite, mica powder and zirconium oxide), 10 parts low melting point glass powder (softening point temperature of 450-550℃). Flame retardant: 20 parts aluminum hydroxide; MOF material: NH2-MIL-68(In)@TpAz 20 parts; Reinforcing layer: A glass fiber layer plated with nickel metal by chemical method (thickness 0.1mm, nickel metal plating thickness 10μm). The glass fiber layer is glass fiber cloth, and its main component is SiO2.

[0034] Step 2: Preparation process: Methyl vinyl silicone rubber, vinyl silicone oil, hydroxyl silicone oil, hydrogen-containing silicone oil, inhibitor and platinum catalyst are mixed evenly under a closed and moisture-proof condition. Then aluminum hydroxide, composite ceramic powder, low melting point glass powder and modified MOF material are added and stirred at high speed until evenly dispersed to obtain ceramicized adhesive. Step 3: First vulcanization and coating: The ceramicized adhesive is coated onto the release paper with a coating thickness of 0.2 mm, and the first vulcanization is carried out at 150°C for 15 minutes; Reinforcing layer bonding and second coating vulcanization: A second coating of ceramicized rubber is applied to the surface of the rubber layer after the first vulcanization. The thickness of the second coating of ceramicized rubber is 0.5mm. The 0.1mm thick reinforcing layer is bonded to the surface of the second coating of ceramicized rubber by a pressure roller to form a preform. The preform is then subjected to a second vulcanization at 180°C for 2 hours, and the preform is cross-linked and cured through the two vulcanization molding process. Post-processing: After vulcanization, the material is cooled and cut to obtain a multifunctional ceramicized glass fiber composite material for battery pack safety protection.

[0035] Example 2 The method is the same as in Example 1, except for the MOF material: 20 parts of NH2-MIL-68(In)@TpBD; Example 3 The method is the same as in Example 1, except that the MOF material is: 20 parts of NH2-UiO-66@TpPa-1; Comparative Example 1 Without adding the surface-modified MOF material (NH2-MIL-68(In)@TpAz), the remaining raw materials, proportions, and preparation process were exactly the same as in Example 1.

[0036] Comparative Example 2 Ordinary glass fiber cloth (i.e., glass fiber cloth without chemical nickel plating, main component: SiO2) was used, and the remaining raw materials, proportions and preparation process were exactly the same as in Example 1.

[0037] Comparative Example 3 Step 1: Rubber compound raw materials: 10 parts 60000-80000 Pa·s methyl vinyl silicone rubber, 20 parts 1000~2000 Pa·s vinyl silicone oil, 20 parts 30-50 Pa·s hydroxyl silicone oil, 8 parts hydrogen-containing silicone oil, 1.5 parts platinum catalyst and 3 parts inhibitor ethynylcyclohexanol; Ceramic filler: 30 parts composite ceramic powder (wollastonite, mica powder and zirconium oxide), 10 parts low melting point glass powder (softening point temperature of 450-550℃). Flame retardant: 20 parts by weight of aluminum hydroxide; Surface-modified MOF material: NH2-MIL-68(In)@TpAz 20 parts by weight; Step 2: Preparation process: Methyl vinyl silicone rubber, vinyl silicone oil, hydroxyl silicone oil, hydrogen-containing silicone oil, inhibitor and platinum catalyst are mixed evenly under a closed and moisture-proof condition. Then aluminum hydroxide, composite ceramic powder, low melting point glass powder and modified MOF material are added and stirred at high speed until evenly dispersed to obtain ceramicized adhesive. Step 3: The thickness requirement of the above-mentioned ceramicized adhesive is set according to the foaming ratio, and the corresponding calendering coating thickness is 0.7mm. The adhesive is coated onto the release paper using a pressure roller and then placed in an oven for primary curing at 150℃ for 15 minutes. A secondary curing is then performed at 180℃ for 2 hours. The ceramicized foam is obtained through the two-stage curing process.

[0038] Comparative Example 4 The steps are the same as in Comparative Example 3. The remaining raw materials, proportions, and preparation process of the ceramicized foam are exactly the same as in Comparative Example 3. The glass fiber layer is not chemically nickel-plated; only glass fiber cloth is used. The specific steps are as follows: A ceramicized adhesive and a glass fiber cloth (without a chemically plated nickel metal layer) are bonded together using a foam-specific silicone material (specific components: methyl vinyl silicone rubber, vinyl silicone oil, hydroxyl silicone oil, hydrogen-containing silicone oil, inhibitor, and platinum catalyst) under the action of a pressure roller. After bonding, the mixture is heated and vulcanized in an oven at 180°C for 2 hours, then cooled and cut to obtain a composite material of ceramicized foam and glass fiber cloth bonded together with silicone material.

[0039] The comprehensive performance of each group of samples was tested, and the results are compared below: Table 1: Comparison of performance test results between the examples and the comparative examples

[0040] The above test results clearly characterize the key roles played by each component of the present invention and their synergistic effect mechanism: The low interfacial bonding strength analysis of Comparative Examples 3 and 4 indicates that the interfacial bonding force generated by simple physical contact or ordinary vulcanization process is limited.

[0041] Example 1: The peel strength improvement far exceeds that of Comparative Examples 1, 2, and 4. This is mainly attributed to the "micro-anchoring" effect of the surface-modified MOF material (taking NH2-MIL-68(In)@TpAz as an example). NH2-MIL-68(In)@TpAz nanoparticles have extremely high specific surface area and abundant surface functional groups. During vulcanization, they can effectively penetrate and accumulate in the interface region between the silica matrix and the glass fiber cloth. Through physical adsorption and coordination bonding, they simultaneously form a strong bond with both, creating a robust "micro-mechanical interlocking" transition layer, thereby greatly enhancing the interlayer bonding force.

[0042] 2. Analysis of the strength and electromagnetic shielding of high-temperature debris Comparative Example 3: The ceramic body formed after ablation of pure ceramicized silicone is porous, fragile, and has low strength.

[0043] Comparative Example 2: The fiberglass cloth served to strengthen the skeleton and improve the strength of the wreckage, but because it had no metal layer, it did not shield electromagnetic waves at all.

[0044] Compared with Comparative Examples 2, 3 and 4, Example 1 showed high strength and shielding performance, demonstrating a synergistic enhancement effect.

[0045] In terms of strength: the surface-modified MOF material improves the interface, making the ceramicized silicone and glass fiber cloth bond more tightly at high temperatures; at the same time, the glass fiber cloth itself softens at high temperatures and partially sintersects with the ceramic body. The presence of the surface-modified MOF material may promote this process, together forming a strong, integrated ceramic-glass fiber composite skeleton with strength far exceeding that of the comparative example.

[0046] Regarding shielding: The nickel plating layer on the surface provides an excellent conductive network, which is the sole reason for achieving highly efficient electromagnetic shielding. Comparative Example 2 lacks this metal plating layer and therefore has no shielding capability.

[0047] Analysis of smoke suppression and toxicity reduction performance in Comparative Examples 1, 3, and 4 showed that the MOF materials without surface modification produced a large amount of smoke and toxic gases during combustion. Compared with Comparative Example 2, Example 1 and Comparative Example 2 showed a sharp decrease in SDR and CO production, and an order-of-magnitude improvement in performance, which is entirely due to the core function of the surface-modified MOF materials.

[0048] Physical adsorption: Taking NH2-MIL-68(In)@TpAz as an example, it has a regular nanoscale pore structure and a huge specific surface area, which can efficiently adsorb the smoke particles generated by combustion like a "sponge", thereby significantly reducing the smoke density (SDR).

[0049] Chemisorption and catalysis: Taking NH2-MIL-68(In)@TpAz as an example, the pores and metal sites have a strong selective adsorption and catalytic decomposition ability for polar small molecule gases (such as CO), which can effectively reduce gas toxicity and decrease CO production.

Claims

1. A multifunctional ceramicized composite material for thermal runaway safety protection of battery packs, characterized in that, It has a layered composite structure, including a smoke-suppressing ceramizable silicone layer, a glass fiber matrix reinforcement layer, and a metal shielding layer composited on the surface of the glass fiber matrix reinforcement layer; The ceramicizable silicone layer of the ceramicized glass fiber composite material is formed by vulcanization and cross-linking curing of raw materials comprising the following parts by weight: 10-30 parts of dry metal-organic framework (MOF) powder modified with COF material surface, 10-30 parts of aluminum hydroxide powder, 10-45 parts of composite ceramic powder, 5-15 parts of low-melting-point glass powder, 10-15 parts of methyl vinyl silicone rubber with a viscosity of 60,000-80,000 Pa·s, 15-35 parts of vinyl silicone oil with a viscosity of 1,000-2,000 Pa·s, 15-35 parts of hydroxyl silicone oil with a viscosity of 30-50 Pa·s, 5-15 parts of hydrogen-containing silicone oil, 1-2 parts of platinum catalyst, and 1-3 parts of inhibitor.

2. The multifunctional ceramicized composite material according to claim 1, characterized in that, The surface-modified metal-organic framework (MOF) dry powder includes at least one of NH2-MIL-125(Ti), NH2-MIL-68(In), or NH2-UiO-66.

3. The multifunctional ceramicized composite material according to claim 1 or 2, characterized in that, The glass fiber reinforcement layer is a glass fiber cloth with a metallized coating on its surface; the metallized coating is a chemically plated nickel layer or an electroplated nickel layer with a thickness of 0.5-10 micrometers; the thickness of the glass fiber cloth is 0.05-0.2 millimeters.

4. The multifunctional ceramicized composite material according to claim 1, characterized in that, The composite ceramic powder is a mixture of two or more of diatomaceous earth, kaolin, mica powder and talc powder; the low melting point glass powder is a phosphate-based or borosilicate-based glass powder with a softening point temperature of 450-550℃.

5. The multifunctional ceramicized composite material according to claim 1, characterized in that, The inhibitor is ethynylcyclohexanol or maleate ester compounds.

6. The multifunctional ceramicized composite material according to claim 1, characterized in that, After being burned in a flame at 800-1000℃ for 10-30 minutes, the tensile strength of the material residue is not less than 2.0 MPa, and it maintains structural integrity without delamination or pulverization.

7. The multifunctional ceramicized composite material according to claim 1, characterized in that, The material has an electromagnetic shielding effectiveness of not less than 35 dB in the 1-10 GHz frequency range.

8. The multifunctional ceramicized composite material according to claim 1, characterized in that, The smoke density rating (SDR) of the material during combustion does not exceed 40, and the carbon monoxide (CO) yield does not exceed 15 mg / g; the room temperature interfacial peel strength between the ceramicized glass fiber composite matrix layer and the glass fiber reinforcement layer is not less than 2 N / mm.

9. A method for preparing the multifunctional ceramicized composite material as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of rubber compound: Methyl vinyl silicone rubber, hydroxyl silicone oil, hydrogen-containing silicone oil, inhibitor and platinum catalyst are mixed evenly under sealed and moisture-proof conditions, and then aluminum hydroxide, composite ceramic powder, low melting point glass powder and MOF material are added. The mixture is stirred at high speed until it is evenly dispersed to obtain ceramicized rubber compound. (2) First vulcanization and coating: The ceramicized adhesive is coated on the release paper and vulcanized for the first time at 120-150℃ for 10-20 minutes; (3) Reinforcing layer bonding and second vulcanization: A second coating is applied to the surface of the rubber layer after the first vulcanization, and the surface metallized glass fiber cloth reinforcing layer is bonded to it by a pressure roller to form a preform; then the preform is vulcanized for the second time at 160-200℃ for 1-2 hours. (4) Post-processing: After vulcanization, the composite material is obtained by cooling and cutting.

10. The application of the multifunctional composite material as described in any one of claims 1-8 in the power battery module or battery pack as an integrated safety barrier material for one or more of the following: fireproofing, heat insulation, smoke suppression, or electromagnetic shielding.

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