Phase change material used in heat insulation system and preparation method and application thereof

Abstract

The invention discloses a phase change material used in a heat insulation system, and a preparation method and application thereof. The phase change material is prepared from the following raw material components in parts by weight: 30-70 parts of dynamic crosslinking vitrimer resin; 20 to 60 parts of a porous skeleton supported phase change material; 1 to 15 parts of a temperature-sensitive self-foaming component; and 0.5 to 10 parts of a cascade response intelligent microcapsule. Through the synergistic effect of the components, the obtained composite material not only has the heat management performance of high heat conductivity, high latent heat, wide temperature range and long cycle life, but also has the passive protection capability of forming a heat insulation barrier by in-situ foaming when encountering high temperature, and the active safety capability of performing millisecond-level active removal when encountering electric arcs; meanwhile, based on the vitrimer matrix, the material also has the characteristics of being repairable and recoverable. The method is suitable for the fields of new energy automobiles, electrochemical energy storage, high-end electronic equipment and the like.

Description

Technical Field

[0001] This invention relates to the field of functional composite materials technology, and in particular to a phase change material for use in thermal insulation systems, its preparation method, and its application. Background Technology

[0002] With the transformation of the global energy structure and the rapid development of information technology, modern electronic and electrical equipment, represented by new energy vehicles, electrochemical energy storage, 5G communication base stations, and high-performance data centers, is developing towards high power density, high integration, and miniaturization. This trend leads to huge heat flux density in the equipment during operation. At the same time, the high-voltage and high-current operating environment also dramatically increases the risk of electrical faults such as internal short circuits and arcing, posing unprecedented and severe challenges to the thermal management and safety protection of the equipment.

[0003] Traditional thermal management solutions typically employ separate systems to address heat dissipation and safety issues. For example, passive heat dissipation is achieved using thermally conductive potting compounds and radiators, while circuit protection is provided by fuses and circuit breakers. This separate design increases the system's weight, size, complexity, and cost, and fails to create synergistic effects at the material level. When thermal management fails, safety risks increase dramatically; and electrical faults are often the trigger for thermal runaway.

[0004] Phase change materials (PCMs) are considered highly promising thermal management materials due to their high heat storage density. However, traditional PCM application solutions face many insurmountable challenges, such as poor cycle stability, volume changes and liquid leakage during the solid-liquid phase change process leading to easy breakage of microcapsules and a sharp decline in heat storage performance after multiple cycles; low utilization rate of latent heat of phase change, with pure PCMs having extremely low thermal conductivity, preventing rapid heat storage and release, resulting in weak actual temperature control; and narrow applicable temperature range, as single-component PCMs only function near a fixed melting point, failing to meet the wide-range thermal management needs of equipment under different operating conditions.

[0005] Existing material-level safety protection mainly relies on the addition of flame retardants. Flame retardants are a form of "passive" protection, meaning they only begin to function after the material has been ignited and a fire has already started. They delay the spread of flames by releasing flame-retardant gases or forming a char layer, but they cannot address the core triggers before a fire occurs—such as instantaneous electric arcing. Electric arcing is the main culprit for equipment fires and explosions, and traditional materials are powerless against it, unable to prevent such incidents. Therefore, there is an urgent need in this field for a phase change material for use in thermal insulation systems, along with its preparation method and applications. Summary of the Invention

[0006] The purpose of this invention is to address the deficiencies in the prior art by proposing a phase change material for use in thermal insulation systems, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: In one aspect of the invention, a phase change material for use in a thermal insulation system is provided, which is a composite material prepared from the following raw material components in parts by weight: Component A: 30 to 70 parts of dynamically crosslinked Vitrimer resin, which serves as a continuous phase matrix for the thermo-adaptive polymer; Component B: 20 ​​to 60 parts of a porous framework-supported phase change material comprising a three-dimensional porous thermally conductive framework and a microencapsulated phase change material physically confined within the framework; Component C: 1 to 15 parts of a temperature-sensitive self-foaming component, which acts as a latent thermal barrier and has a preset activation threshold temperature at which it can generate gas through irreversible chemical decomposition and synergistically form a porous ceramicized carbon layer in situ with component A; and Component D: 0.5 to 10 parts of cascaded response smart microcapsules, which serve as multi-level active safety response modules.

[0008] Furthermore, the cascaded response smart microcapsule in component D comprises: a first core material that is sensitive to an electric field gradient or a high temperature of >500°C as a first threshold and is used for gas-phase quenching and arc extinguishing; And a second core material that is sensitive to a medium temperature (150°C-300°C) as a second threshold, used to interrupt the combustion chain reaction; Furthermore, the composite material further comprises 0.1 to 5 parts by weight of a molecular-level arc quencher for chemically neutralizing free radicals in arc plasma.

[0009] Furthermore, the polymer network of the dynamically crosslinked Vitrimer resin of component A contains dynamic covalent bonds based on reversible ester exchange, imine exchange, or disulfide bond exchange reactions; and the composite material further contains a rheology modifier for precisely controlling its thixotropic and shear-thinning behavior during the pre-curing stage.

[0010] Furthermore, component B has one or more of the following technical features: a) The microencapsulated phase change material comprises microcapsules having a self-healing shell wall made of a microencapsulated repair agent, and is a mixture of at least two phase change material microcapsules having multiple different phase change temperature points with a gradient distribution. b) The three-dimensional porous thermally conductive framework is graphene aerogel, boron nitride foam, or metal foam; c) The core material of the microencapsulated phase change material is selected from paraffin, higher fatty acids, higher fatty alcohols or hydrated salts.

[0011] According to another aspect of the present invention, the present invention provides a method for preparing the above-mentioned phase change material.

[0012] A method for preparing a phase change material for use in a thermal insulation system includes the following steps: S1: The surfaces of functional filler components (microcapsules in component B, component C, and component D) are chemically grafted using silane coupling agents to form a chemically bridging interface layer, thereby enhancing compatibility with the resin matrix.

[0013] S2: Differentiated shear conditions are used to mix the components in steps. First, the skeleton and powder are dispersed under high shear force, and then microcapsules are gently mixed in under low shear force to ensure that the system is uniform and the functional components are structurally intact.

[0014] S3: Vacuum degassing is performed on the mixed premix to eliminate internal bubble defects that affect the performance of the final product.

[0015] S4: The premix is ​​cured and molded using a thermal planning process that includes multiple stages such as low-temperature leveling, controlled gelation and high-temperature post-treatment, in order to optimize the final performance of the material.

[0016] Furthermore, the surface chemical grafting treatment using a silane coupling agent described in step S1 is to form a covalent bond bridge between the surface of the functional filler and the prepolymer of component A. The silane coupling agent contains a first functional group that can react with hydroxyl groups or other active groups on the filler surface, and a second functional group that can participate in the cross-linking and curing reaction of the prepolymer of component A.

[0017] Furthermore, the multi-step stepped thermal curing process described in step S4 specifically includes the following stages executed sequentially: a) Low-temperature leveling stage: The premix is ​​kept at a temperature T1 (e.g., 40°C to 60°C) below the gelation initiation temperature of the prepolymer for a first preset time (e.g., 30 to 90 minutes) to reduce the viscosity of the premix, fully wet the substrate and complete self-leveling. b) Controlled gelation stage: The temperature is increased to the gelation temperature T2 (e.g., 80°C to 120°C) at a first preset heating rate of 1 to 5°C / min and held at this temperature for a second preset time (e.g., 60 to 120 minutes) until the prepolymer of component A solidifies and sets into a three-dimensional chemically cross-linked network with preliminary structural strength; and c) High-temperature post-treatment stage: The temperature is increased to a post-treatment temperature T3 (e.g., 150°C to 180°C) higher than the glass transition temperature Tg of the final cured product of component A at a second preset heating rate and held at a constant temperature for a third preset time (e.g., 60 to 180 minutes) to drive the cross-linking reaction to fully relax the internal stress of the material and activate the dynamic covalent bonds to establish the topological reversibility of its network.

[0018] On another aspect, the present invention provides applications of the aforementioned phase change material, which serves as a multifunctional thermal management and active safety protection material for the encapsulation and protection of electrochemical energy storage systems, solid or semi-solid power battery packs, aerospace-grade power electronic modules, deep-sea equipment, or data center immersion liquid cooling systems.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: Through component design, efficient thermal management functions and multi-level active and passive safety protection functions are integrated into a single material system. The components work together to stabilize the temperature during daily operation and provide full-chain protection from arc extinguishing and fire suppression to thermal insulation in the event of a fault, avoiding the problems of functional separation and lack of synergy. By introducing cascaded response smart microcapsules and arc quenchers, the material acquires active safety characteristics, enabling it to identify and eliminate electrical faults such as arcs within milliseconds of their occurrence, truly preventing problems before they occur. At the same time, combined with the temperature-sensitive self-foaming component, it forms a "firewall" that can be created at high temperatures, thus providing double protection. By employing a porous framework load to address the leakage problem of phase change materials, shape stability is achieved. The high thermal conductivity framework significantly improves the thermal conductivity and latent heat utilization of the system. Furthermore, the self-healing design of the microcapsule shell wall and the combination of multi-temperature zone PCMs enhance the cycling stability and operational adaptability of the material over a wide temperature range. By using dynamically cross-linked Vitrimer resin as the matrix, the material can effectively relax internal stress during the curing process, improving its compatibility and reliability with components. It also possesses repairable, remodelable, and recyclable properties, thereby extending the material's service life, reducing the maintenance costs of high-end electronic devices, and conforming to the global trend of green environmental protection and circular economy. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0021] Figure 1 This is a flowchart of the method for preparing composite phase change materials in the embodiments of the present invention; Figure 2 This is a schematic cross-sectional view of the cascaded response smart microcapsule in an embodiment of the present invention. Figure 3 This is a comparison chart of temperature response curves from the simulated temperature control buffer effect test in this embodiment of the invention; Figure 4 This is a comparison chart of the back temperature response curves in the in-situ foaming insulation test of a specific embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] This invention provides a multifunctional composite phase change material for use in thermal insulation systems, its preparation method, and its applications. The composite material integrates multiple properties such as efficient thermal management, active safety protection (arc extinguishing, fire suppression), fault isolation, and recyclability through the synergistic effect of various functional components. The technical solution of this invention will be described in detail below with reference to several embodiments.

[0024] like Figure 1-2 As shown, in a preferred embodiment, a multifunctional composite phase change material for use in a thermal insulation system comprises the following components: Component A: Dynamically crosslinked vitrimer resin. This resin serves as the continuous phase matrix of the composite material, providing fundamental mechanical properties, electrical insulation properties, and environmental tolerance for the entire system. This invention preferably uses vitrimer resin, whose polymer network contains dynamically reversible covalent bonds, such as chemical bonds based on reversible ester exchange, imine exchange (Schiff base reaction), or disulfide bond exchange reactions. The chemical structure allows the network topology of the cured composite material to rearrange at specific temperatures (typically above its glass transition temperature Tg), thereby endowing the material with unprecedented capabilities for thermal repair, shape reshaping, and even closed-loop recycling and reprocessing. In embodiments of this invention, epoxy vitrimer composed of an epoxy anhydride system and an ester exchange catalyst such as zinc acetate, or polyimide vitrimer composed of polyaldehyde monomers reacted with polyamine monomers, can be selected.

[0025] Component B: Porous framework-supported phase change material. This porous framework-supported phase change material is used to achieve thermal management functions and is a structured composite system containing: Three-dimensional porous thermally conductive framework: Serving as a carrier for PCM, it provides structural support, prevents leakage of PCM in the molten state, and achieves shape stability. Simultaneously, the framework itself possesses high thermal conductivity, enabling the construction of an efficient thermally conductive network that accelerates the absorption and release of heat throughout the composite material, thereby improving temperature control response speed. Preferred framework materials include, but are not limited to, graphene aerogel, boron nitride foam, or highly thermally conductive metal foams (such as copper foam).

[0026] Microencapsulated phase change materials (PCMs): These fill the pores within a framework. They absorb and release a large amount of latent heat through solid-liquid or solid-solid phase transitions at specific temperatures, acting as isothermal buffers and stabilizing the operating temperature. To achieve wide-temperature-range and high-stability thermal management, in a preferred embodiment of this invention, a PCM system is employed, for example: Multi-temperature zone PCM mixture: PCM microcapsules with different phase change temperatures (such as 45°C, 60°C, 80°C) are compounded to meet the graded temperature control requirements under different working conditions.

[0027] Self-healing shell wall microcapsules: The shell wall of the microcapsules (such as polyurethane-urea) contains microencapsulated repair agents (such as isocyanates and polyols), which can self-repair when the shell wall develops microcracks due to long-term cycling, greatly improving the cycle life and stability of PCM.

[0028] Optional core materials include, but are not limited to, organic PCMs such as n-eicosane (melting point approximately 37°C) and stearic acid (melting point approximately 70°C), or inorganic hydrated salt PCMs such as disodium hydrogen phosphate dodecahydrate.

[0029] Component C: Temperature-sensitive self-foaming component. The temperature-sensitive self-foaming component is a latent gas-generating agent that remains stable at normal operating temperatures. However, when the temperature reaches its activation threshold (e.g., >250°C), it will rapidly undergo irreversible chemical decomposition, releasing a large amount of non-flammable gases (e.g., CO2, N2). The generation of these gases will drive the already softened resin matrix to expand and synergistically undergo a carbonization reaction, ultimately forming a dense, porous, low thermal conductivity ceramicized carbon layer on or inside the material surface. This ceramicized carbon layer acts as an instantaneously generated thermal insulation barrier, effectively blocking heat transfer, protecting adjacent components, and preventing the chain reaction of thermal runaway.

[0030] The preferred component C is a classic intumescent flame retardant system, such as melamine-modified ammonium polyphosphate (MPP-APP).

[0031] Component D: Cascaded response smart microcapsules, which are dual-core or multi-core microcapsules capable of providing graded responses to different fault signals, wherein: The first-level response is the arc quenching response: the outer layer of the microcapsule or one of the core wall materials is highly sensitive to the instantaneous strong electric field or ultra-high temperature (>500°C) generated by the electric arc, and will rupture instantly, releasing the first core material used for gas phase quenching, such as perfluorohexanone (Novec1230) and other highly efficient and environmentally friendly arc quenching media.

[0032] The second-level response is the fire suppression response: the inner layer of the microcapsule or the wall material of another core is sensitive to moderate temperatures (150°C-300°C) of ordinary overheating. If overheating continues after the arc is extinguished, the layer will rupture and release a second core material, such as a gaseous free radical scavenger like triethyl phosphate, to interrupt the combustion chain reaction.

[0033] Furthermore, in a preferred embodiment, to further enhance the arc quenching effect, molecular-level arc quenchers, such as halogen-containing compounds or metal oxide nanoparticles, can be added to the composite material to neutralize the arc plasma at a chemical level.

[0034] The composite material of the present invention may further include a rheology modifier. The main function of the rheology modifier is to precisely control the viscosity, thixotropy (i.e., high viscosity when standing and low viscosity when stirred) and shear thinning behavior of the premix during the pre-curing stage, so as to prevent high-density functional fillers (such as components B, C, and D) from settling before curing and to ensure the morphological stability of the product under different construction processes (such as potting and coating). In a specific embodiment of the present invention, the rheology modifier may be selected from one or more of the following combinations: Nanoscale inorganic fillers, such as fumed silica or hydrophobically modified fumed silica, are used to form a three-dimensional hydrogen bond network in the resin matrix, thereby providing excellent anti-settling and thickening effects.

[0035] Organically modified clays: such as organically modified montmorillonite or organic bentonite, are used to control rheology by peeling and intercalating their layered structure in resin to form a network structure. High molecular weight polymers: such as specific cellulose derivatives or polyamide waxes, used to adjust the viscosity of the system by entanglement or crystallization of molecular chains.

[0036] To better understand the technical solution of the present invention, the present invention will be further illustrated below through specific preparation examples.

[0037] Example 1 This embodiment provides a composite phase change material with balanced performance, the formulation (parts by weight) is as follows: Component A: 50 parts of epoxy Vitrimer resin prepolymer; Component B: Graphene aerogel-supported phase change material, 40 parts. (Of which graphene aerogel accounts for 5 parts, and the remainder is a mixture of two types of PCM microcapsules: 20 parts of paraffin microcapsules with a melting point of 45°C and 15 parts of stearic acid microcapsules with a melting point of 70°C. Both types of microcapsules have a polyurethane self-healing shell wall.) Component C: 8 parts of melamine polyphosphate (MPP); Component D: Dual-core intelligent microcapsules, 3 portions; Molecular-grade arc quencher (decabromodiphenyl ethane), 1 part; Rheology modifier (fumed silica), 2 parts; Silane coupling agent (KH-550), 1.5 parts; Curing catalyst (zinc acetate), 0.5 parts; A method for preparing a composite phase change material with balanced performance: S1: The PCM microcapsules in component B, component C and component D were placed in toluene solvent, and 1.5 parts of silane coupling agent KH-550 were added. The mixture was stirred at 60°C for 4 hours, then filtered and dried to obtain the surface-grafted modified functional filler.

[0038] S2: In a planetary mixer, first mix 50 parts of epoxy Vitrimer resin prepolymer, 0.5 parts of curing catalyst, and 2 parts of rheology modifier until homogeneous. Then, at a high shear rate of 2000 rpm, add the graphene aerogel from component B and the modified component C, and stir for 30 minutes. Subsequently, reduce the speed to a low shear rate of 200 rpm, add the PCM microcapsules from the modified component B, component D, and 1 part of arc quencher, and continue stirring for 20 minutes to obtain a homogeneous premix.

[0039] S3: Place the premix in a vacuum oven and perform multi-stage degassing treatment at 50°C and -0.09MPa for 60 minutes.

[0040] S4: Pour the degassed premix into the mold and perform the following stepped curing process: S401: Maintain a constant temperature of 60°C for 60 minutes (low temperature leveling stage).

[0041] S402: Heat to 110°C at a rate of 2°C / min and hold at that temperature for 90 minutes (controlled gelation stage).

[0042] S403: Heat to 170°C at a rate of 3°C / min and hold at that temperature for 120 minutes (high-temperature post-treatment stage).

[0043] S404: Finally, allow it to cool naturally to room temperature and demold to obtain the final composite phase change material sample.

[0044] Example 2 The same preparation method as in Example 1 was used, but the formulation was adjusted to enhance active safety performance: Formula (parts by weight): Component A: 45 parts; Component B: 35 parts; Component C: 8 parts; Component D: 10 parts; Molecular-level arc quencher: 2 parts.

[0045] The remaining components were adjusted accordingly.

[0046] Example 3 The same preparation method as in Example 1 was used, but the formulation was adjusted to enhance thermal management performance: Formula (parts by weight): Component A: 30 parts; Component B: 60 parts; Component C: 5 parts; Component D: 2 parts; The remaining components were adjusted accordingly.

[0047] To verify the comprehensive performance of the composite phase change material prepared in the embodiments of the present invention, we selected samples from Examples 1, 2, and 3, and set up two comparative examples for comparative testing.

[0048] Comparative Example 1: A conventional commercial epoxy resin potting compound with only 15 parts by weight of aluminum hydroxide added as a conventional flame retardant.

[0049] Comparative Example 2: "Functionally Defective" Sample. Its formulation is identical to Example 1, but it does not contain Component D (cascade-response smart microcapsules) and molecular-level arc quencher. This comparative example aims to verify the critical role of the active safety module (Component D, etc.).

[0050] Thermal management performance test Thermal conductivity test: The thermal conductivity of each sample was tested at 25°C using a thermal interface material thermal conductivity tester conforming to ASTM D5470 standard.

[0051] Phase change performance test: The phase transition temperature (melting peak temperature) and latent heat of phase transition of the sample were tested using a differential scanning calorimeter (DSC) under a nitrogen atmosphere at a heating and cooling rate of 10°C / min.

[0052] Simulated temperature control buffer effect test: A 5 mm thick sample was placed on a precisely temperature-controlled heating plate, with a thermocouple positioned at the center of the sample's upper surface. The heating plate was heated from 30°C to 100°C at a rate of 20°C / min. The temperature change curve of the thermocouple on the upper surface was recorded, along with the time required for the upper surface temperature to reach 90°C. The longer the time, the stronger the material's thermal buffering capacity.

[0053] Security performance test Vertical burning test: The flame retardancy rating of a 3.2mm thick sample was assessed in accordance with the UL-94 vertical burning test standard.

[0054] In-situ foaming insulation test: A 10 mm thick sample was placed in a muffle furnace at 500°C and heated for 5 minutes. Its expansion and foaming were then observed. Simultaneously, in another set of experiments, the front of the sample was scorched with a flame torch (approximately 800°C), and the temperature of the back of the 10 mm thick sample was measured after 60 seconds.

[0055] Arc extinguishing performance test: In the test apparatus, an electrode gap of 5 mm is set, and a DC voltage of 1000V is applied to ignite an arc through a momentary short circuit. The arc current is limited to 10A. The sample is pre-filled around the electrodes. The time required for the arc to extinguish from its inception is recorded using a high-speed camera and oscilloscope. If the arc continues to burn for more than 1000 milliseconds or ignites the sample, it is recorded as "arc extinguishing failure".

[0056] Cyclic stability test (a) Phase change latent heat retention rate: The sample was subjected to 500 DSC heating and cooling cycles (within a 20°C range above and below the phase transition temperature). The initial latent heat of phase transition and the latent heat of phase transition after 500 cycles were tested and compared, and the latent heat retention rate was calculated. In practical applications, for example, the composite material prepared according to this invention can be applied between the cells of a power battery pack for new energy vehicles in the form of potting compound or flexible thermally conductive pads. During normal charging and discharging, component B can effectively absorb and release heat, balancing the battery temperature; when an internal short circuit occurs in a cell, component D can respond instantaneously and suppress the arc, and component C can foam to form a heat insulation layer when the temperature rises further, effectively blocking the propagation of thermal runaway to adjacent cells, thereby controlling the fault at the smallest unit and greatly improving the safety of the entire battery pack. At the same time, its repairable and recyclable characteristics also provide great convenience for the cascade utilization and final recycling of batteries, as shown in Table 1.

[0057] Table 1 Test Project unit Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Thermal management performance thermal conductivity W / (m·K) 3.5 3.1 5.2 0.6 3.5 Phase transition latent heat J / g 125.4 108.2 155.8 0 125.4 Temperature control buffer time s 186 165 225 32 186 Safety performance UL-94 flammability rating - V-0 V-0 V-0 V-2 V-0 Foamed carbon layer thickness mm ~18 ~18 ~15 No foaming ~18 Backside temperature (60s) °C 95 92 110 >400 95 Arc extinguishing time ms 85 45 98 Arc extinguishing failure Arc extinguishing failure Cyclic stability Latent heat retention rate (500 cycles) % 97.2 96.8 97.5 - 81.3 like Figure 3-4As shown above, all embodiments exhibit excellent latent heat storage capacity and temperature control buffering effect due to the presence of component B, far exceeding Comparative Example 1, which lacks phase change capability. Example 3, employing a high thermal conductivity framework and a high-load PCM, demonstrates the most outstanding thermal conductivity and overall thermal management performance. All embodiments achieve the highest V-0 flame retardant rating, and due to the presence of component C, a thick insulating char layer can be formed at high temperatures, resulting in significantly better insulation than Comparative Example 1. Examples 1, 2, and 3 can all extinguish arcs quickly, while Comparative Example 2, lacking an active safety module, fails to extinguish arcs. This irrefutably proves the decisive role of component D and the arc quencher in actively eliminating electrical faults. Example 2, with the highest content of active safety components, exhibits the fastest arc extinguishing speed. The latent heat of Example 1 remained at 97.2% after 500 cycles, while that of Comparative Example 2 (assuming its PCM microcapsules have ordinary shells) showed a significant decrease. This demonstrates the important contribution of the self-healing microcapsule technology in this invention to the long-term reliability of materials.

[0058] In summary, the composite phase change material provided by this invention, through the synergistic design of its components, possesses obvious technical advantages in thermal management, active and passive safety protection, and long-term stability that are unmatched by traditional materials.

[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A phase change material for use in a thermal insulation system, characterized in that, It is a composite material prepared from the following raw material components in parts by weight: Component A: 30 to 70 parts of dynamically crosslinked Vitrimer resin, which serves as a continuous phase matrix for the thermo-adaptive polymer; Component B: 20 ​​to 60 parts of a porous framework supported phase change material comprising a three-dimensional porous thermally conductive framework and a microencapsulated phase change material physically confined within the three-dimensional porous thermally conductive framework; Component C: 1 to 15 parts of temperature-sensitive self-foaming component, which acts as a latent thermal barrier and has a preset activation threshold temperature. At the activation threshold temperature, it can generate gas through irreversible chemical decomposition and form a porous ceramic carbon layer in situ in conjunction with component A. as well as Component D: 0.5 to 10 parts of cascaded response smart microcapsules, which serve as multi-level active safety response modules.

2. The phase change material for use in a thermal insulation system according to claim 1, characterized in that, The cascaded response smart microcapsule in component D comprises: a first core material that is sensitive to an electric field gradient as a first threshold or a high temperature of >500°C and is used for gas-phase quenching and arc extinguishing. And a second core material that is sensitive to medium temperature as a second threshold and is used to interrupt the combustion chain reaction; Furthermore, the composite material further comprises 0.1 to 5 parts by weight of a molecular-level arc quencher for chemically neutralizing free radicals in arc plasma.

3. The phase change material for use in a thermal insulation system according to claim 1, characterized in that, The polymer network of the dynamically crosslinked Vitrimer resin of component A contains dynamic covalent bonds based on reversible ester exchange, imine exchange, or disulfide bond exchange reactions. Furthermore, the composite material further comprises a rheology modifier for precisely controlling its thixotropic and shear-thinning behavior during the pre-curing stage.

4. The phase change material for use in a thermal insulation system according to claim 3, characterized in that, Component B has one or more of the following technical features: a) The microencapsulated phase change material comprises microcapsules having a self-healing shell wall made of a microencapsulated repair agent, and is a mixture of at least two phase change material microcapsules having multiple different phase change temperature points with a gradient distribution. b) The three-dimensional porous thermally conductive framework is graphene aerogel, boron nitride foam, or metal foam; c) The core material of the microencapsulated phase change material is selected from paraffin, higher fatty acids, higher fatty alcohols or hydrated salts.

5. A method for preparing a phase change material for use in a thermal insulation system, for preparing the phase change material for use in a thermal insulation system as described in claim 3, characterized in that, Includes the following steps: S1: At least one of the microencapsulated phase change material in component B, component C, and component D is chemically grafted onto the surface using a silane coupling agent to form a chemically bridging interface layer between the component and the prepolymer of component A. S2: Under high shear conditions, the three-dimensional porous thermally conductive framework in component B and component C are uniformly dispersed in the prepolymer of component A. Then, under low shear planetary stirring conditions aimed at maintaining the integrity of the microcapsule structure, the microencapsulated phase change material in component B after step S1 and component D are added to form a uniform premix. S3: Perform multi-stage depressurization vacuum degassing treatment on the premix obtained in step S2; S4: Apply the premix obtained in step S3 to the substrate or mold and perform a multi-step stepped thermosetting curing process.

6. The method for preparing phase change material for use in thermal insulation systems according to claim 5, characterized in that, The surface chemical grafting treatment using silane coupling agent described in step S1 involves forming a covalent bond bridge between the surface of at least one of the microencapsulated phase change material in component B, component C, and component D, and the prepolymer of component A. The silane coupling agent contains a first functional group that can react with hydroxyl groups or other active groups on the filler surface, and a second functional group that can participate in the cross-linking and curing reaction of the prepolymer of component A.

7. The method for preparing phase change material for use in thermal insulation systems according to claim 5, characterized in that, The multi-step stepped thermal curing process described in step S4 specifically includes the following stages performed sequentially: a) Low-temperature leveling stage: The premix is ​​kept at a temperature T1 below the gelation initiation temperature of the prepolymer for a first preset time to reduce the viscosity of the premix, fully wet the substrate and complete the self-leveling. b) Controlled gelation stage: The temperature is increased to the gelation temperature T2 at a first preset heating rate of 1 to 5°C / min and held at a constant temperature for a second preset time until the prepolymer of component A forms a three-dimensional chemical cross-linked network with preliminary structural strength and is solidified and shaped. c) High-temperature post-treatment stage: The temperature is raised to a post-treatment temperature T3, which is higher than the glass transition temperature Tg of the final cured product of component A, at a second preset heating rate and held at a constant temperature for a third preset time, so as to drive the cross-linking reaction to be complete, fully relax the internal stress of the material, and activate the dynamic covalent bonds to establish the topological reversibility of its network.

8. An application of a phase change material in a thermal insulation system as described in any one of claims 1 to 4, characterized in that, As a multifunctional thermal management and active safety protection material, it is used in the encapsulation and protection of electrochemical energy storage systems, solid or semi-solid power battery packs, aerospace-grade power electronic modules, deep-sea equipment, or data center immersion liquid cooling systems.

9. The application of the phase change material in a thermal insulation system according to claim 8, characterized in that, Its applications include: achieving isothermal buffering within the normal operating range through the latent heat absorption of the phase change material in component B; The component C expands in situ during the initial stage of thermal runaway to form a physical barrier and block the spread of heat. Furthermore, it achieves synergistic chemical composite fault clearing through component D and arc quencher when encountering internal short-circuit arcing.

10. The application of the phase change material in a thermal insulation system according to claim 9, characterized in that, After use, the phase change material can be used for in-situ damage repair, device disassembly and replacement, or closed-loop recycling and reprocessing of materials by heating it globally or locally to above the topological rearrangement temperature of the dynamically cross-linked Vitrimer resin in component A.

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