Universal composite thermal insulation material adaptive to multiple types of power batteries and preparation method of universal composite thermal insulation material

Abstract

The invention provides a universal composite thermal insulation material adaptive to multiple types of power batteries and a preparation method of the universal composite thermal insulation material. The composite thermal insulation material comprises a heat conduction integration layer, a modular thermal insulation interlayer and a protective hydrophobic layer which are sequentially arranged from inside to outside, wherein the protective hydrophobic layer comprises a first fiber base material and a hydrophobic sealing layer compounded on the surface of the first fiber base material; the modular heat insulation interlayer is obtained by compounding the graphene quantum dots and the functional filler with SiO2 aerogel, and the customization requirements of different types of power batteries can be met by adjusting the doping amount of the graphene quantum dots and the functional filler; the heat conduction integration layer is composed of a second fiber base material and a plurality of metal heat conduction elements embedded in the first surface of the second fiber base material. According to the scheme, external water vapor invasion can be effectively blocked, performance degradation and internal metal element corrosion caused by moisture absorption of the middle layer can be prevented, universal adaptation to lithium iron phosphate, ternary lithium and sodium ion batteries can be achieved, meanwhile, independent heating films or cooling fins do not need to be additionally arranged, and the space of the battery pack in the height direction is saved.

Description

Technical Field

[0001] This invention relates to the field of thermal management materials technology for new energy power batteries, and in particular to a general-purpose composite thermal insulation material adaptable to multiple types of power batteries and its preparation method. Background Technology

[0002] New energy vehicle power batteries come in a variety of types, including lithium iron phosphate, ternary lithium, and sodium-ion batteries, and their thermal management requirements differ significantly: lithium iron phosphate batteries need to enhance their high-temperature heat dissipation capabilities, ternary lithium batteries need to focus on suppressing the spread of thermal runaway, while sodium-ion batteries have the problem of difficulty starting up in low-temperature environments.

[0003] In response to the above problems, the related technologies widely adopt composite heat insulation using needle-punched felt and aerogel. However, in the actual application process, the following key technical defects have been gradually exposed: (1) Poor universal adaptability: The existing aerogel material formula is fixed and the interlayer thickness is not adjustable. It is difficult to flexibly adapt to the thermal conductivity-temperature characteristics of various battery materials in the same production line. As a result, the OEM needs to design heat insulation structures separately for different batteries, which significantly increases the development cost and cycle; (2) Insufficient reliability in humid and hot environments: The nanoscale porous structure of aerogel is easy to adsorb moisture in the environment through the macroscopic pores of needle-punched felt. After absorbing moisture, it not only reduces the heat insulation performance, but may also corrode the battery aluminum busbar due to the ion migration caused by deliquescence, affecting the service life of the system; (3) Thermal management components occupy effective space: Traditional solutions require additional configuration of independent heating film or heat dissipation structure, which occupies the valuable space of the battery pack in the height direction, which is contrary to the current development trend of thinner and lighter battery systems with higher energy density.

[0004] Therefore, there is an urgent need to provide a universal composite thermal insulation material that is compatible with multiple types of power batteries and its preparation method. Summary of the Invention

[0005] This invention provides a universal composite thermal insulation material adaptable to multiple types of power batteries and its preparation method, which can solve the problems of poor universal adaptability, insufficient reliability in humid and hot environments, and the encroachment of effective space by thermal management components on existing thermal insulation materials.

[0006] In a first aspect, the present invention provides a universal composite thermal insulation material adaptable to multiple types of power batteries. The composite thermal insulation material includes a thermally conductive integrated layer, a modular thermal insulation interlayer, and a protective hydrophobic layer arranged sequentially from the inside out. The protective hydrophobic layer includes a first fiber substrate and a hydrophobic sealing layer composited on its surface. The modular thermal insulation interlayer is obtained by composite SiO2 aerogel with graphene quantum dots and functional fillers. Adjusting the doping amount of graphene quantum dots and functional fillers can meet the customized requirements of different types of power batteries. The thermally conductive integrated layer is composed of a second fiber substrate and a plurality of metal thermally conductive elements embedded in its first surface.

[0007] Preferably, the first fiber substrate is a hollow pre-oxidized fiber needle-punched felt; wherein the fiber diameter of the needle-punched felt is 3~12μm, the hollowness is 20~55%, and the needle-punching density is 10~40 needles / cm. 2 The surface density is 50~120 g / m³ 2 .

[0008] Preferably, the hydrophobic sealing layer is a polytetrafluoroethylene film, and the thickness of the hydrophobic sealing layer is 2~10μm.

[0009] Preferably, the functional filler includes at least one of flame-retardant filler, thermally conductive filler, or electrically conductive filler.

[0010] Preferably, the flame-retardant filler is magnesium hydroxide particles; the thermally conductive filler is at least one of nano-alumina or boron nitride microplates; and the conductive filler is carbon nanotubes.

[0011] More preferably, the doping amount of the functional filler is 0~5wt%.

[0012] More preferably, the doping amount of the graphene quantum dots is 2~10wt%.

[0013] Preferably, for ternary lithium batteries, the graphene quantum dot content in the modular thermal insulation interlayer is 4~6 wt%; For aluminum iron phosphate batteries, the doping amount of graphene quantum dots in the modular thermal insulation interlayer is 6~8wt%, and the doping amount of functional fillers is 1~5wt%. For sodium-ion batteries, the doping amount of graphene quantum dots in the modular heat insulation interlayer is 2~4wt%, and the doping amount of functional fillers is 1~3wt%.

[0014] Preferably, the second fiber substrate is a dense pre-oxidized fiber needle-punched felt; wherein the fiber diameter of the needle-punched felt is 2~5μm, and the needle-punching density is 20~30 needles / cm. 2 The surface density is 50~80 g / m³ 2 .

[0015] Preferably, the metal heat-conducting element is a copper foil strip; wherein each copper foil strip has a thickness of 0.05~0.2mm, a width of 0.5~2mm, and a spacing of 5~15mm between two adjacent copper foil strips.

[0016] Preferably, the copper foil strip is embedded along the length of the first surface of the second fiber substrate, and both ends extend to the edge of the second fiber substrate to form a standard snap or laser welding interface to achieve docking with the battery pack heat sink or PTC heater.

[0017] Preferably, the second surface of the second fiber substrate is provided with a microgroove array to achieve mechanical interlocking between the thermally conductive integrated layer and the modular thermal insulation interlayer.

[0018] More preferably, the microgroove array is formed by a number of V-shaped microgrooves extending continuously on the surface of the second fiber substrate; wherein the depth of each microgroove is 10~30μm.

[0019] Preferably, the extension direction of each microgroove on the second surface forms an angle greater than 0 with the extension direction of the metal heat-conducting element disposed on the first surface; the angle is preferably 30°~60°.

[0020] Preferably, at least one support strip is provided between the thermally conductive integrated layer and the protective hydrophobic layer for adjusting the spacing between the thermally conductive integrated layer and the protective hydrophobic layer.

[0021] Preferably, each support bar has an anchoring structure at both ends to form a mechanical interlock with the thermally conductive integrated layer and the protective hydrophobic layer, respectively.

[0022] Preferably, the support strip is para-aramid 1313, polyimide fiber, or pre-oxidized silicone rubber composite fiber; the length of the support strip is 2~5mm, and the spacing between two adjacent support strips is 20~40mm.

[0023] Secondly, embodiments of the present invention also provide a method for preparing a universal composite thermal insulation material adaptable to multiple types of power batteries as described in any of the first aspects above, the preparation method comprising the following steps: (1) A hydrophobic slurry is sprayed onto the surface of the first fiber substrate and dried to form a hydrophobic sealing layer on the surface of the first fiber substrate, thereby obtaining a protective hydrophobic layer. (2) A metal thermally conductive element is embedded along the first surface of the second fiber substrate using an embedded injection molding process, and a micro-groove array is set on the second surface of the second fiber substrate using a press to obtain a thermally conductive integrated layer; (3) According to the customized requirements of different types of power batteries, graphene quantum dots, functional fillers and silica precursor sol are mixed to obtain a mixed sol. At least one support strip is provided between the protective hydrophobic layer and the thermally conductive integrated layer to fix the thermally conductive integrated layer and the protective hydrophobic layer and form a cavity between them. The mixed sol is pressure injected into the cavity, and after passing through sol-gel, aging treatment and supercritical drying treatment in sequence, the general-purpose composite heat insulation material adapted to multiple types of power batteries is obtained.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The composite thermal insulation material in this invention adopts an integrated design, consisting of a thermally conductive integrated layer, a modular thermal insulation interlayer, and a protective hydrophobic layer from the inside out. The outer protective hydrophobic layer forms an effective moisture barrier by constructing a dense hydrophobic sealing layer on the surface of the fiber substrate, thereby effectively blocking the intrusion of external water vapor and preventing the performance degradation of the middle aerogel due to moisture absorption and the corrosion of internal metal components, thus ensuring the long-term service life and reliability of the battery system in complex humid and hot environments. The middle modular thermal insulation interlayer uses SiO2 aerogel as the matrix and precisely adjusts the graphene quantum... The doping ratio of the filler and functional filler can be flexibly adjusted to control key parameters such as thermal conductivity or flame retardancy, thereby enabling the rapid fabrication of thermal insulation interlayers adapted to different battery types such as ternary lithium, lithium iron phosphate, and sodium-ion batteries, significantly reducing production costs. Meanwhile, the thermally conductive integrated layer, which is in direct contact with the battery, can efficiently and directly interface with the battery pack heat dissipation system or PTC heater by embedding metal thermal conductive elements on the surface of the fiber substrate, eliminating the need for additional independent heating films or heat dissipation fins. This saves valuable space in the height direction of the battery pack, achieving a thinner and lighter design while ensuring high energy density of the battery system.

[0025] (2) In some preferred embodiments, the present invention uses an in-situ gelation process and a microgroove array on the second surface of the thermally conductive integrated layer to achieve a bonding strength of up to 1.6 MPa within the composite thermal insulation material, ensuring extremely high structural integrity. Experiments have shown that after a rigorous 100,000 vibration tests (10~2000 Hz, 20g acceleration), the interlayer shedding rate is less than 0.3%, demonstrating superior mechanical durability and safety reliability. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of a universal composite heat insulation material adapted to multiple types of power batteries provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the first surface of the thermally conductive integrated layer in a universal composite thermal insulation material adapted to multiple types of power batteries provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the second surface of the thermally conductive integrated layer in a universal composite thermal insulation material adapted to multiple types of power batteries provided in an embodiment of the present invention; Figure 4This is a schematic diagram of the structure of the thermally conductive integrated layer, the protective hydrophobic layer, and the support strip in a universal composite thermal insulation material adapted to multiple types of power batteries provided in an embodiment of the present invention. In the diagram: 100 - protective hydrophobic layer, 200 - modular thermal insulation interlayer, 300 - thermally conductive integrated layer, 400 - support strip, 301 - metal thermally conductive element, 302 - microgroove array. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, this embodiment of the invention provides a universal composite thermal insulation material adaptable to multiple types of power batteries. The composite thermal insulation material includes a thermally conductive integrated layer 300, a modular thermal insulation interlayer 200, and a protective hydrophobic layer 100 arranged sequentially from the inside out. The protective hydrophobic layer 100 includes a first fiber substrate and a hydrophobic sealing layer composited on its surface. The modular thermal insulation interlayer 200 is obtained by composite SiO2 aerogel with graphene quantum dots and functional fillers. Adjusting the doping amount of graphene quantum dots and functional fillers can meet the customized requirements of different types of power batteries. The thermally conductive integrated layer 300 is composed of a second fiber substrate and a plurality of metal thermally conductive elements embedded in its first surface.

[0030] like Figure 1As shown, the composite thermal insulation material in this embodiment of the invention adopts an integrated design, consisting of a thermally conductive integrated layer, a modular thermal insulation interlayer, and a protective hydrophobic layer from the inside out. The outer protective hydrophobic layer forms an effective moisture barrier by constructing a dense hydrophobic sealing layer on the surface of the fiber substrate. This effectively blocks external moisture intrusion, preventing performance degradation of the middle aerogel layer due to moisture absorption and corrosion of internal metal components, thus ensuring the long-term service life and reliability of the battery system in complex humid and hot environments. The middle modular thermal insulation interlayer uses SiO2 aerogel as a matrix, with the amount of graphene precisely adjusted. The doping ratio of sub-dots and functional fillers can be flexibly adjusted to control key parameters such as thermal conductivity or flame retardancy, thereby enabling the rapid fabrication of thermal insulation interlayers adapted to different battery types such as ternary lithium, lithium iron phosphate, and sodium-ion batteries, significantly reducing production costs. Meanwhile, the thermally conductive integrated layer, which is in direct contact with the battery, can efficiently and directly interface with the battery pack heat dissipation system or PTC heater by embedding metal thermal conductive elements on the surface of the fiber substrate, eliminating the need for additional independent heating films or heat dissipation fins. This saves valuable space in the height direction of the battery pack, achieving a thinner and lighter design while ensuring high energy density of the battery system.

[0031] According to some preferred embodiments, the first fiber substrate is a hollow pre-oxidized fiber needle-punched felt; wherein the fiber diameter of the needle-punched felt is 3~12μm (e.g., 3μm, 5μm, 8μm, 10μm or 12μm), the hollowness is 20~55% (e.g., 20%, 30%, 40%, 50% or 55%), and the needle-punching density is 10~40 needles / cm. 2 (For example, it can be 10 stitches / cm) 2 20 stitches / cm 2 30 stitches / cm 2 Or 40 stitches / cm 2 The areal density is 50~120 g / m³. 2 (For example, it can be 50g / m 2 80g / m 2 100g / m 2 Or 120g / m 2 The hydrophobic sealing layer is a polytetrafluoroethylene film, and the thickness of the hydrophobic sealing layer is 2~10μm (for example, it can be 2μm, 3μm, 5μm, 8μm or 10μm).

[0032] In this embodiment of the invention, the hollow pre-oxidized fiber itself possesses excellent high-temperature resistance. By opening, combing, and needle-punching the hollow pre-oxidized fiber, and controlling the needle-punching density, a needle-punched felt with suitable areal density and hollowness is prepared. This felt structure provides an ideal supporting skeleton for the hydrophobic coating and a good interface for subsequent composite with the modular thermal insulation interlayer. While achieving excellent thermal insulation and lightweighting, it also helps to ensure the integrity of the overall material structure. Furthermore, a hydrophobic sealing layer is sprayed onto the outer surface of the hollow pre-oxidized fiber needle-punched felt (the side facing the external environment of the battery pack) to form a dense hydrophobic layer of a certain thickness. This effectively blocks water vapor and protects the internal materials from corrosion. Experiments of this invention have confirmed that if the thickness of the dense hydrophobic layer is too low, it is not conducive to the formation of a complete continuous film, and pinhole defects are prone to occur, leading to water vapor intrusion and reduced wear resistance. If the thickness of the dense hydrophobic layer is too high, it may lead to a decrease in the material's flexibility, posing a risk of cracking during repeated bending.

[0033] According to some preferred embodiments, the functional filler includes at least one of flame-retardant filler, thermally conductive filler, or electrically conductive filler; the flame-retardant filler is magnesium hydroxide particles; the thermally conductive filler is at least one of nano-alumina or boron nitride microplates; and the electrically conductive filler is carbon nanotubes; the doping amount of the functional filler is 0~5wt% (for example, it can be 0wt%, 1wt%, 2wt%, 3wt%, 4wt%, or 5wt%); and the doping amount of the graphene quantum dots is 2~10wt% (for example, it can be 2wt%, 3wt%, 5wt%, 8wt%, 9wt%, or 10wt%).

[0034] In this embodiment of the invention, SiO2 aerogel with a porosity of 90-98% is used as the matrix, and a basic system is formed by doping with a certain amount of graphene quantum dots. Graphene quantum dots can construct a stable support network in the nanopore walls of the aerogel, enhancing the mechanical strength and toughness of the aerogel material and improving its thermal stability, ensuring structural integrity under extreme conditions such as thermal runaway. By precisely controlling the doping amount of graphene quantum dots, the thermal conductivity of the material can be finely controlled. At the same time, by further adding flame-retardant (such as magnesium hydroxide) or conductive (such as carbon nanotubes) functional fillers, or partially using low-cost thermally conductive functional fillers such as nano-alumina and boron nitride (replacement ratio ≤50 wt%), the modular thermal insulation interlayer can be endowed with flame-retardant or low-temperature electrothermal activation functions, thereby meeting the customized needs of different types of power batteries. In summary, by modularly designing the basic system and functional fillers, and by adjusting the composition and ratio of graphene quantum dots and functional fillers, modular thermal insulation sandwich layers suitable for different battery types such as ternary lithium, lithium iron phosphate, and sodium ion can be rapidly prepared without separate design. This is beneficial for significantly improving production efficiency and reducing development costs.

[0035] According to some preferred embodiments, for ternary lithium batteries, the doping amount of graphene quantum dots in the modular heat insulation interlayer is 4~6wt% (for example, it can be 4wt%, 4.5wt%, 5wt%, 5.5wt%, or 6wt%). For aluminum iron phosphate batteries, the doping amount of graphene quantum dots in the modular heat insulation interlayer is 6~8wt% (for example, it can be 6wt%, 6.5wt%, 7wt%, 7.5wt% or 8wt%), and the doping amount of functional filler is 1~5wt% (for example, it can be 1wt%, 2wt%, 3wt%, 4wt% or 5wt%). For sodium-ion batteries, the doping amount of graphene quantum dots in the modular heat insulation interlayer is 2~4wt% (for example, it can be 2wt%, 2.5wt%, 3wt%, 3.5wt% or 4wt%), and the doping amount of functional filler is 1~3wt% (for example, it can be 1wt%, 1.5wt%, 2wt%, 2.5wt% or 3wt%).

[0036] The modular heat insulation interlayer in this embodiment of the invention can be customized according to different battery types. Each model is formed in one step using an in-situ sol-gel combined supercritical drying process. The thickness can be adjusted within the range of 2 to 5 mm. It also supports online composite with outer / inner needle-punched felt, enabling rapid model changeover on a single production line. This sandwich system features customizable composition and performance, specifically including three adaptable models: The basic model (for ternary lithium batteries) has 4-6 wt% graphene quantum dots and a thermal conductivity of 0.016-0.020 W / (m·K) in the temperature range of -20 to 60℃ (tested at 25℃), exhibiting excellent and stable thermal insulation performance; Customized Model 1 (for lithium iron phosphate batteries) has 6-8 wt% graphene quantum dots and 1-5 wt% functional filler (flame-retardant filler), ensuring an oxygen index of no less than 32% and high flame-retardant properties, effectively improving battery system safety; Customized Model 2 (for sodium-ion batteries) has 2-4 wt% graphene quantum dots and 1-3 wt% functional filler (conductive filler), with a thermal conductivity of no more than 0.022 W / (m·K) at -40℃, ensuring effective heat preservation under extremely cold conditions.

[0037] According to some preferred embodiments, the second fiber substrate is a dense pre-oxidized fiber needle-punched felt; wherein the fiber diameter of the needle-punched felt is 2~5μm (for example, it can be 2μm, 3μm, 4μm, or 5μm), and the needle-punching density is 20~30 needles / cm. 2 (For example, it can be 20 stitches / cm) 2 25 stitches / cm 2 or 30 stitches / cm 2The surface density is 50~80 g / m³. 2 (For example, it can be 50g / m 2 60g / m 2 70g / m 2 Or 80g / m 2 ).

[0038] In this embodiment of the invention, a low-area-density needle-punched felt is manufactured from dense pre-oxidized filament fibers through opening, carding, and needle-punching processes. Based on the inherent high-temperature resistance and flame-retardant properties of pre-oxidized filament fibers, this needle-punched felt structure enhances the overall thermal stability of the material, acting as a safety barrier under extreme conditions such as battery thermal runaway, effectively delaying heat propagation and improving system safety. Simultaneously, this needle-punched felt structure not only provides a stable mechanical anchor for the subsequent embedding of metal thermal conductive elements, giving the material excellent peel strength and tear resistance, but also possesses good flexibility and compressibility, enabling it to tightly adhere to the battery surface and adapt to irregular spaces within the battery pack.

[0039] According to some preferred embodiments, such as Figure 3 As shown, the metal heat-conducting element is a copper foil strip; wherein, the thickness of each copper foil strip is 0.05~0.2mm (for example, it can be 0.05mm, 0.1mm, 0.15mm or 0.2mm), the width is 0.5~2mm (for example, it can be 0.5mm, 1mm, 1.5mm or 2mm), and the spacing between two adjacent copper foil strips is 5~15mm (for example, it can be 5mm, 8mm, 10mm or 15mm); the copper foil strip is embedded along the length direction of the first surface of the second fiber substrate, and both ends extend to the edge of the second fiber substrate to form a standard snap or laser welding interface to achieve docking with the battery pack heat sink or PTC heater.

[0040] In this embodiment of the invention, a plurality of copper foil strips are disposed on the first surface of the second fiber substrate facing the battery, thereby constructing a highly efficient and integrated heat-conducting channel on the surface of the fiber substrate. By rationally controlling the thickness, width, and spacing between adjacent copper foil strips, the structure is made lightweight and flexible to the maximum extent while ensuring an effective heat-conducting cross-section, allowing it to conform to the irregular shape of the battery surface. Simultaneously, by extending both ends of each copper foil strip to the edge of the substrate to form standard snap-fit ​​or laser-welded interfaces, it can be directly connected to the battery pack heat sink or PTC heater, eliminating the need for additional wires and connection steps, significantly improving assembly efficiency and achieving a rapid thermal response of ≤10 s. When the battery temperature is above 80°C, the heat-conducting channel formed by the copper foil strips can conduct local heat to the heat sink, achieving rapid cooling. When the battery temperature is below -20°C, the heat-conducting channel formed by the copper foil strips can receive heat from the PTC heater and uniformly transfer it to the battery surface, thereby improving heat preservation efficiency.

[0041] It should be noted that the processing method of the heat conduction channel in this embodiment of the invention is not specifically limited. For example, embedded injection molding can be used, where copper foil is inserted after pre-punching holes in the second fiber substrate and then injection molded and edge-wrapped in one go; laser spot welding can also be used, where copper foil strips are directly laid on the surface of the second fiber substrate and then spot welded at intervals, eliminating the need for injection molds and increasing the single-line production cycle by 30%. At the same time, to meet the harsh operating environment, a 2 mm exposed area is reserved at both ends of the copper foil strip. The surface can be nickel-plated or coated with an insulating epoxy layer to improve salt spray resistance and meet the IP67 protection level requirements, thereby improving the system's environmental adaptability while ensuring electrical safety.

[0042] According to some preferred embodiments, such as Figure 2 As shown, the second surface of the second fiber substrate is provided with a microgroove array to achieve mechanical interlocking between the thermally conductive integrated layer and the modular thermal insulation interlayer; the microgroove array is formed by a number of V-shaped microgrooves extending continuously on the surface of the second fiber substrate; wherein, the depth of each microgroove is 10~30μm (for example, it can be 10μm, 20μm or 30μm).

[0043] According to some preferred embodiments, the extension direction of each microgroove on the second surface forms an angle greater than 0 with the extension direction of the metal heat-conducting element disposed on the first surface; the angle is preferably 30° to 60° (for example, it can be 30°, 45° or 60°).

[0044] In this embodiment of the invention, a microgroove array is formed on the second surface of the second fiber substrate facing the modular thermal insulation layer by hot pressing (180-220℃, 0.3-0.8MPa). This structure transforms the contact mode between the modular thermal insulation layer and the thermally conductive integrated layer from a two-dimensional planar contact to a three-dimensional mechanical interlocking structure, significantly increasing the effective contact area between the modular thermal insulation layer and the thermally conductive integrated layer. The array consists of several V-shaped microgrooves. After hot pressing, the grooves form barbed interlocks with the aerogel nanoframework, transforming the original two-dimensional planar contact into a three-dimensional interlock. Simultaneously, their extension direction intersects the heat-conducting channels formed by the copper foil strips at a certain angle, thus generating anti-peeling shear force on the groove walls regardless of whether they are subjected to lateral or longitudinal force. Furthermore, in this embodiment, the included angle is preferably 45°, which has symmetrical characteristics, ensuring uniform force on the grooves during bidirectional feeding of the hot pressing roller and preventing orientational tearing of the fibers. Combined with an appropriate microgroove depth, this achieves an interlayer peel strength increase of ≥25% while maintaining the mechanical integrity of the thermally conductive integrated layer, fundamentally eliminating the risk of interfacial thermal short circuits.

[0045] According to some preferred embodiments, at least one support strip is further provided between the thermally conductive integrated layer and the protective hydrophobic layer for adjusting the spacing between the thermally conductive integrated layer and the protective hydrophobic layer; Each support strip has anchoring structures at both ends to form mechanical interlocks with the thermally conductive integrated layer and the protective hydrophobic layer, respectively; the support strip is made of para-aramid 1313, polyimide fiber, or pre-oxidized silicone rubber composite fiber; the length of the support strip is 2-5mm (for example, it can be 2mm, 3mm, 4mm or 5mm), and the spacing between two adjacent support strips is 20-40mm (for example, it can be 20mm, 30mm or 40mm).

[0046] In embodiments of the present invention, such as Figure 4 As shown, by further setting at least one temperature-resistant elastic support strip between the thermally conductive integrated layer and the protective hydrophobic layer, precise control of the cavity structure between the thermally conductive integrated layer and the protective hydrophobic layer can be achieved. The support strips are arranged in parallel at a certain interval and are embedded in the thermally conductive integrated layer and the protective hydrophobic layer through anchoring structures (preferably T-shaped) formed by hot pressing at both ends. This effectively prevents displacement or collapse during the composite process, thereby controlling the overall thickness tolerance within ±0.1mm. By replacing the support strips of different heights (2 mm, 3 mm, 4 mm, 5 mm), the interlayer thickness can be quickly adjusted from 2 to 5 mm on the same production line, thus precisely adapting to the space requirements of different battery packs such as ternary lithium batteries (thin type 2 mm) and sodium-ion batteries (thick type 5 mm). This structure, while achieving flexible thickness switching, can give the material a certain compression resilience, which is beneficial for effectively buffering the expansion stress of the cell during cycle use and extending the overall service life of the battery.

[0047] It should be noted that, in order to ensure better performance, the support strip material is selected from para-aramid 1313, polyimide staple fiber or pre-oxidized fiber / silicone rubber composite fiber, with a single filament diameter of 0.5~1.5 mm, temperature resistance ≥350 ℃, elastic modulus of 0.8~2.0 GPa, and elongation at break ≥15%.

[0048] This invention also provides a method for preparing a universal composite thermal insulation material adaptable to multiple types of power batteries as described in any of the above claims, the preparation method comprising the following steps: (1) A hydrophobic slurry is sprayed onto the surface of the first fiber substrate and dried to form a hydrophobic sealing layer on the surface of the first fiber substrate, thereby obtaining a protective hydrophobic layer. (2) A metal thermally conductive element is embedded along the first surface of the second fiber substrate using an embedded injection molding process, and a micro-groove array is set on the second surface of the second fiber substrate using a press to obtain a thermally conductive integrated layer; (3) According to the customized requirements of different types of power batteries, graphene quantum dots, functional fillers and silica precursor sol are mixed to obtain a mixed sol. At least one support strip is provided between the protective hydrophobic layer and the thermally conductive integrated layer to fix the thermally conductive integrated layer and the protective hydrophobic layer and form a cavity between them. The mixed sol is pressure injected into the cavity, and after passing through sol-gel, aging treatment and supercritical drying treatment in sequence, the general-purpose composite heat insulation material adapted to multiple types of power batteries is obtained.

[0049] In some specific embodiments, the mixed sol is prepared by the following method: (31) The precursor solution, alcohol solvent, acid catalyst, and functional modifier are mixed to obtain a silica precursor sol; wherein the precursor solution is methyl orthosilicate or ethyl orthosilicate, the alcohol solvent is methanol or ethanol, the acid catalyst is hydrochloric acid or sulfuric acid, and the functional modifier is graphene quantum dots and functional fillers; the molar ratio of the precursor solution, alcohol solvent, pure water, and acid catalyst is 10:8:(0.4~0.6):(0.5~0.7); specifically, for ternary lithium batteries, the silica precursor... In the silica precursor sol, graphene quantum dots account for 4-6 wt% of the total mass of the precursor sol; for aluminum iron phosphate batteries, graphene quantum dots account for 6-8 wt% of the total mass of the silica precursor sol, and functional fillers account for 1-5 wt% of the total mass of the precursor sol; for sodium-ion batteries, graphene quantum dots account for 2-4 wt% of the total mass of the silica precursor sol, and functional fillers account for 1-3 wt% of the total mass of the precursor sol. (32) Add a fluorosilane hydrophobic agent (tridecylfluorooxy or perfluorodecyl type) to the silica precursor sol and stir for 30-35 min to obtain a mixed sol; wherein the amount of fluorosilane hydrophobic agent added is 2wt% of the total amount of silica precursor sol.

[0050] In this embodiment of the invention, a corresponding mixed sol is selected and prepared according to the customized requirements of different types of power batteries; then, a support strip of appropriate length is selected to fix the outer protective hydrophobic layer and the inner thermally conductive integrated layer, so that a cavity is formed between the two; the mixed sol is pressure injected (injection pressure is 0.2~0.3MPa) into the cavity, and then sequentially undergoes sol-gel, gradient aging treatment and supercritical drying treatment, specifically in three stages of gradient aging treatment; wherein, the temperature of the first stage is 60~70℃ and the time is 0.5~1.5h; the temperature of the second stage is 80~90℃ and the time is 1.5~2.5h; the temperature of the third stage is 40~50℃ and the time is 0.5~1.0h. A fluorosilane hydrophobic agent is added during the preparation of the mixed sol, which co-condenses in situ within the aerogel to generate low surface energy groups such as Si-CH3 / CF3, giving it intrinsic hydrophobic properties. Furthermore, after curing, a vacuum infiltration process is employed to infiltrate an ethanol dispersion of 1-5 wt% solid content and 5-50 nm particle size nano-hydrophobic particles (such as silica, alumina, or boron nitride) into the aerogel pores at -0.07 to -0.09 MPa for 15 minutes, thereby constructing a 20-100 nm thick hydrophobic shell on the surface, forming a bi-level hydrophobic structure. This structure further increases the contact angle, and after 30 days in an environment with 85% relative humidity, the water absorption rate does not exceed 2.1%, and the thermal insulation performance degradation rate is controlled within 3%, effectively solving the performance degradation problem of materials under long-term use in humid and hot environments.

[0051] Furthermore, to address the interfacial heat loss issue caused by the simple stacking of needle-punched felt and aerogel in traditional solutions, after obtaining the protective hydrophobic layer and the thermally conductive integrated layer, the two layers were impregnated with a 1-10 wt% silane coupling agent ethanol solution at room temperature to optimize the interface. Subsequently, they were dried at 80±5℃ for 3-8 min to form a molecular-level adhesive film with a thickness of 10-50 nm. Sol-gel casting was then performed on this pretreatment basis, allowing the sol to penetrate the needle-punched felt and co-condense with the film layer, forming a fiber-Si-O-Si-aerogel chemically bridged structure. This interfacial coupling method reduces the thermal resistance at the fiber-aerogel interface, further enhances the interlayer peel strength, and achieves low thermal conductivity fluctuations within the temperature range of -40℃ to 80℃, significantly outperforming the thermal insulation stability and bonding reliability of traditional physical stacking schemes.

[0052] In summary, this invention achieves universal compatibility with mainstream power battery types through a modular intermediate layer and adjustable sandwich structure design, eliminating the need for separate mold design and significantly reducing production costs. Regarding interface treatment, the needle-punched felt is pre-impregnated with a silane coupling agent before aerogel encapsulation to form a molecular-level bonding layer, effectively reducing the thermal resistance at the fiber-aerogel interface and improving thermal insulation stability. After dual-stage hydrophobic modification, the material's water absorption rate is only 2.1% after 30 days in an 85% humidity environment, and the thermal insulation performance degradation is controlled within 2.7%, demonstrating excellent moisture resistance and long-term durability. The integrated embedded heat conduction channel achieves rapid linkage response with the battery pack thermal management system without occupying additional space, aligning with the trend of battery pack miniaturization. Furthermore, the in-situ gel and surface micro-texture interlocking design achieves an interlayer bonding strength of 1.6 MPa, and the shedding rate is less than 0.3% after 100,000 vibration tests at 10~2000 Hz and 20g acceleration, demonstrating excellent mechanical reliability and vibration durability.

[0053] To more clearly illustrate the technical solution and advantages of the present invention, the following describes in detail, through several embodiments, a general-purpose composite thermal insulation material adaptable to multiple types of power batteries and its preparation method.

[0054] Example 1: (1) Hollow pre-oxidized fibers (fiber diameter 3~12μm) are sequentially opened, carded and needle-punched (50 needles / cm2) to produce fibers with a hollow rate of 30% and a surface density of 80g / m2. 2 The first fiber substrate (hollow pre-oxidized fiber needle-punched felt); a polytetrafluoroethylene (PTFE) dispersion with a solid content of 8 wt% is sprayed on the outer surface of the first fiber substrate, and after being dried by hot air at 110℃ for 3 min, a 5 μm hydrophobic sealing layer is formed on the surface of the first fiber substrate to obtain a protective hydrophobic layer. (2) Dense pre-oxidized fibers (fiber diameter 2~5μm) are subjected to the same opening, carding and needle punching (25 needles / cm). 2 After that, it is made with a surface density of 60g / m³. 2 The second fiber substrate (dense pre-oxidized fiber needle-punched felt); Four copper foil strips, each 0.1 mm thick and 1 mm wide, are embedded along the length of the first surface of the second fiber substrate using an embedded injection molding process. The two ends of the copper foil strips are extended to the edge of the second fiber substrate to form standard snaps for docking with the heat sink of the battery pack. The spacing between two adjacent copper foil strips is 5 mm. A pressing machine is used to set several V-shaped microgrooves on the second surface of the second fiber substrate to form a microgroove array on the surface of the thermally conductive integrated layer, thus obtaining the thermally conductive integrated layer; the extension direction of each microgroove forms a 45° angle with the extension direction of the copper foil strip disposed on the first surface; the depth of each microgroove is 20μm; (3) According to the customized requirements of ternary lithium batteries, the precursor solution (tetraethyl orthosilicate), alcohol solvent (ethanol), acid catalyst (hydrochloric acid) and functional modifier (graphene quantum dots) were mixed at 500 r / min for 2 h at 30℃ to obtain silica precursor sol; wherein, the molar ratio of precursor solution, alcohol solvent, pure water, acid catalyst and functional modifier was 10:8:0.5:0.5, and the doping amount of graphene quantum dots in silica precursor sol was 5wt%; 3wt% of fluorosilane hydrophobic agent (tridecylfluorooxy) was added to silica precursor sol and stirred for 30 min to obtain mixed sol; The inner surface of the protective hydrophobic layer obtained in step (1) and the second surface of the thermally conductive integrated layer obtained in step (2) were respectively immersed in a 5% silane coupling agent ethanol solution for 10 min and dried at 80°C for 5 min to form a molecular-level adhesive film with a thickness of 30 nm. Three 2mm long support strips (para-aramid 1313) are placed between the protective hydrophobic layer and the thermally conductive integrated layer to fix the thermally conductive integrated layer and the protective hydrophobic layer and form a cavity between them. The above-obtained mixed sol is pressure-injected (injection pressure is 0.3MPa) into the cavity. After sol-gel treatment, aging treatment and supercritical drying treatment are performed in sequence, a general-purpose composite thermal insulation material suitable for multiple types of power batteries is obtained. The temperature of the first stage is 60℃ and the time is 1.0h; the temperature of the second stage is 80℃ and the time is 2.0h; the temperature of the third stage is 40℃ and the time is 0.5h. After curing, a vacuum infiltration process is further used to infiltrate the pores of the aerogel with a solid content of 3wt% and a particle size of 10 nm silica nano-hydrophobic particles into the aerogel at -0.08 MPa for 15 minutes, thereby constructing 50 on the surface. The outer shell is nm thick and hydrophobic; the spacing between two adjacent support bars is 30 mm, and each support bar has a T-shaped anchoring structure at both ends to form a mechanical interlock with the thermally conductive integrated layer and the protective hydrophobic layer respectively.

[0055] Example 2: (1) Hollow pre-oxidized fibers (fiber diameter 3~12μm) are sequentially opened, combed and needle-punched (50 needles / cm). 2 After that, it is made with a hollow ratio of 50% and a surface density of 100g / m³. 2The first fiber substrate (hollow pre-oxidized fiber needle-punched felt); a polytetrafluoroethylene (PTFE) dispersion with a solid content of 15 wt% is sprayed on the surface of the first fiber substrate, and after being dried by hot air at 140 ℃ for 3 min, an 8 μm hydrophobic sealing layer is formed on the surface of the first fiber substrate, thus obtaining a protective hydrophobic layer. (2) Dense pre-oxidized fibers (fiber diameter 2~5μm) are subjected to the same opening, carding and needle punching (25 needles / cm). 2 After that, it is made with a surface density of 80g / m³. 2 The second fiber substrate (dense pre-oxidized fiber needle-punched felt); Three copper foil strips, each 0.2 mm thick and 1.5 mm wide, are embedded along the length of the second fiber substrate using an embedded injection molding process. The two ends of the copper foil strips are extended to the edge of the second fiber substrate to form standard snaps for docking with the heat sink of the battery pack. The spacing between two adjacent copper foil strips is 8 mm. A pressing machine is used to set several V-shaped microgrooves on the second surface of the second fiber substrate to form a microgroove array on the surface of the thermally conductive integrated layer, thus obtaining the thermally conductive integrated layer; the extension direction of each microgroove forms a 45° angle with the extension direction of the copper foil strip disposed on the first surface; the depth of each microgroove is 20μm; (3) According to the customized requirements of aluminum iron phosphate battery, the precursor solution (tetraethyl orthosilicate), alcohol solvent (ethanol), acid catalyst (hydrochloric acid) and functional modifier (graphene quantum dots) were mixed at 500 r / min for 2 h at 30℃ to obtain silica precursor sol; wherein, the molar ratio of precursor solution, alcohol solvent, pure water, acid catalyst and functional modifier was 10:8:0.5:0.5, the doping amount of graphene quantum dots in silica precursor sol was 7wt%, and the doping amount of functional filler (magnesium hydroxide) was 3wt%; 3wt% of fluorosilane hydrophobic agent (tridecylfluorooxy) was added to silica precursor sol and stirred for 30 min to obtain mixed sol; The inner surface of the protective hydrophobic layer obtained in step (1) and the second surface of the thermally conductive integrated layer obtained in step (2) were respectively immersed in a 5% silane coupling agent ethanol solution for 10 min and dried at 80°C for 5 min to form a molecular-level adhesive film with a thickness of 30 nm. Three 3mm long support strips (para-aramid 1313) are placed between the protective hydrophobic layer and the thermally conductive integrated layer to fix the thermally conductive integrated layer and the protective hydrophobic layer and form a cavity between them. The above-obtained mixed sol is pressure-injected (injection pressure is 0.5MPa) into the cavity. After sol-gel treatment, aging treatment and supercritical drying treatment are performed in sequence, a general-purpose composite thermal insulation material suitable for multiple types of power batteries is obtained. The temperature of the first stage is 60℃ and the time is 1.0h; the temperature of the second stage is 80℃ and the time is 2.0h; the temperature of the third stage is 40℃ and the time is 0.5h. After curing, a vacuum infiltration process is further used to infiltrate the pores of the aerogel with a solid content of 3wt% and a particle size of 10 nm silica nano-hydrophobic particles into the aerogel at -0.08 MPa for 15 minutes, thereby constructing 50 on the surface. The outer shell is nm thick and hydrophobic; the spacing between two adjacent support bars is 30 mm, and each support bar has a T-shaped anchoring structure at both ends to form a mechanical interlock with the thermally conductive integrated layer and the protective hydrophobic layer respectively.

[0056] Example 3: (1) Hollow pre-oxidized fibers (fiber diameter 3~12μm) are sequentially opened, combed and needle-punched (50 needles / cm). 2 After that, it is made with a hollow ratio of 20% and a surface density of 120 g / m³. 2 The first fiber substrate (hollow pre-oxidized fiber needle-punched felt); a polytetrafluoroethylene (PTFE) dispersion with a solid content of 5 wt% is sprayed on the surface of the first fiber substrate, and after being dried by hot air at 180 ℃ for 4 min, a 2 μm hydrophobic sealing layer is formed on the surface of the first fiber substrate, thus obtaining a protective hydrophobic layer. (2) Dense pre-oxidized fibers (fiber diameter 2~5μm) are subjected to the same opening, carding and needle punching (25 needles / cm). 2 After that, it is made into a surface density of 50g / m³. 2 The second fiber substrate (dense pre-oxidized fiber needle-punched felt); Several copper foil strips with a thickness of 0.1 mm and a width of 1 mm are embedded along the length of the second fiber substrate using an embedded injection molding process. The two ends of the copper foil strips are extended to the edge of the second fiber substrate to form standard snaps to connect with the heat sink of the battery pack. The spacing between two adjacent copper foil strips is 5 mm. A pressing machine is used to set several V-shaped microgrooves on the second surface of the second fiber substrate to form a microgroove array on the surface of the thermally conductive integrated layer, thus obtaining the thermally conductive integrated layer; the extension direction of each microgroove forms a 45° angle with the extension direction of the copper foil strip disposed on the first surface; the depth of each microgroove is 30μm; (3) According to the customized requirements of sodium-ion batteries, the precursor solution (tetraethyl orthosilicate), alcohol solvent (ethanol), acid catalyst (hydrochloric acid) and functional modifier (graphene quantum dots) were mixed at 500 r / min for 2 h at 30 °C to obtain silica precursor sol; wherein, the molar ratio of precursor solution, alcohol solvent, pure water, acid catalyst and functional modifier was 10:8:0.5:0.5, the doping amount of graphene quantum dots in silica precursor sol was 3wt%, and the doping amount of functional filler (carbon nanotubes) was 2wt%; 3wt% of fluorosilane hydrophobic agent (tridecylfluorooxy) was added to silica precursor sol and stirred for 30 min to obtain mixed sol; The inner surface of the protective hydrophobic layer obtained in step (1) and the second surface of the thermally conductive integrated layer obtained in step (2) were respectively immersed in a 5% silane coupling agent ethanol solution for 10 min and dried at 80°C for 5 min to form a molecular-level adhesive film with a thickness of 30 nm. Three 5mm long support strips (para-aramid 1313) are placed between the protective hydrophobic layer and the thermally conductive integrated layer to fix the thermally conductive integrated layer and the protective hydrophobic layer and form a cavity between them. The above-obtained mixed sol is pressure-injected (injection pressure is 0.3MPa) into the cavity. After sol-gel treatment, aging treatment and supercritical drying treatment are performed in sequence, a general-purpose composite thermal insulation material suitable for multiple types of power batteries is obtained. The temperature of the first stage is 60℃ and the time is 1.0h; the temperature of the second stage is 80℃ and the time is 2.0h; the temperature of the third stage is 40℃ and the time is 0.5h. After curing, a vacuum infiltration process is further used to infiltrate the pores of the aerogel with a solid content of 3wt% and a particle size of 10 nm silica nano-hydrophobic particles into the aerogel at -0.08MPa for 15min, thereby constructing 50 on the surface. The outer shell is nm thick and hydrophobic; the spacing between two adjacent support bars is 30 mm, and each support bar has a T-shaped anchoring structure at both ends to form a mechanical interlock with the thermally conductive integrated layer and the protective hydrophobic layer respectively.

[0057] Example 4: Example 4 is basically the same as Example 1, except that: in step (2), a pressing machine is used to set several micro-grooves with a cross-section of U on the second surface of the second fiber substrate to form a micro-groove array on the surface of the thermally conductive integrated layer to obtain the thermally conductive integrated layer; the extension direction of each micro-groove is at a 0° angle (i.e. parallel to each other) with the extension direction of the copper foil strip set on the first surface; the depth of each micro-groove is 20μm.

[0058] Example 5: Example 5 is basically the same as Example 1, except that: in step (3), no fluorosilane hydrophobic agent was added when preparing the mixed sol.

[0059] Example 6: Example 6 is basically the same as Example 1, except that in step (3), the inner surface of the protective hydrophobic layer obtained in step (1) and the second surface of the thermally conductive integrated layer obtained in step (2) are not respectively immersed in the silane coupling agent ethanol solution.

[0060] Example 7 Example 7 is basically the same as Example 1, except that in step (3), the hydrophobic particles were not permeated into the aerogel pores after curing using a vacuum permeation process.

[0061] Example 8 Example 8 is basically the same as Example 2, except that in step (3), the doping amount of graphene quantum dots in the silica precursor sol is 12wt%, and the doping amount of functional filler (magnesium hydroxide) is 1wt%.

[0062] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that in step (2), a copper foil strip is not embedded in the length direction of the first surface of the second substrate.

[0063] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that in step (1), hydrophobic slurry was not sprayed on the surface of the first fiber substrate.

[0064] Comparative Example 3 Comparative Example 3 is basically the same as Example 1, except that: in step (2), a microgroove array is not provided on the second surface of the second fiber substrate.

[0065] Comparative Example 4 Comparative Example 4 is basically the same as Example 1, except that graphene quantum dots were not doped when preparing the mixed sol in step (3).

[0066] Comparative Example 5 Comparative Example 5 is basically the same as Example 1, except that: in step (3), according to the customized requirements of ternary lithium batteries, the precursor solution (tetraethyl orthosilicate), alcohol solvent (ethanol), acid catalyst (hydrochloric acid) and functional modifier (graphene quantum dots) are mixed at 500 r / min for 2 h at 30°C to obtain silica precursor sol; wherein, the molar ratio of precursor solution, alcohol solvent, pure water, acid catalyst and functional modifier is 10:8:0.5:0.5, and the doping amount of graphene quantum dots in silica precursor sol is 5wt%; 3wt% of fluorosilane hydrophobic agent (tridecylfluorooxy) is added to silica precursor sol and stirred for 30 min to obtain mixed sol; The above-obtained mixed sol was pressure-injected (injection pressure of 0.3 MPa) into the mold cavity, and after sequential sol-gel, aging treatment and supercritical drying treatment, a modular aerogel thermal insulation interlayer was obtained. The temperature of the first stage was 60℃ and the time was 1.0 h; the temperature of the second stage was 80℃ and the time was 2.0 h; the temperature of the third stage was 40℃ and the time was 0.5 h. After curing, a vacuum infiltration process was further used to infiltrate an ethanol dispersion of silica nano-hydrophobic particles with a solid content of 3 wt% and a particle size of 10 nm into the pores of the aerogel at -0.08 MPa for 15 min, thereby constructing a 50 nm thick hydrophobic shell on the surface. By sequentially stacking the thermally conductive integrated layer, the modular thermal insulation interlayer, and the protective hydrophobic layer, a universal composite thermal insulation material suitable for various types of power batteries is obtained.

[0067] The performance of the general-purpose composite thermal insulation material samples adapted to various types of power batteries provided in the examples and comparative examples was tested, and the test results are shown in Table 1 below: Thermal insulation performance testing standard: GB / T 10295-2008 "Determination of steady-state thermal resistance and related properties of thermal insulation materials - heat flow meter method"; Moisture resistance test standard: GB / T20312-2006 "Determination of hygroscopic properties of building materials and products"; Combined with the strength testing standard: GB / T 2790 "Adhesives 180° Peel Strength Test Method for Flexible Materials vs. Rigid Materials"; Interlayer shedding rate test standard: % of floating area after 100,000 vibrations (10–2000 Hz, 20 g) GB / T21563-2018 "Impact and Vibration Tests for Rail Transit Locomotives and Rolling Stock Equipment"; Standard for thermal insulation performance degradation test: Appendix C of GB / T 17794-2021 "Flexible foam rubber and plastic thermal insulation products" - Damp heat aging test method.

[0068] Table 1 Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A universal composite thermal insulation material adaptable to multiple types of power batteries, characterized in that, The composite thermal insulation material comprises, from the inside out, a thermally conductive integrated layer, a modular thermal insulation interlayer, and a protective hydrophobic layer; wherein, the protective hydrophobic layer comprises a first fiber substrate and a hydrophobic sealing layer composited on its outer surface; the modular thermal insulation interlayer is obtained by composite SiO2 aerogel with graphene quantum dots and functional fillers, and the customized requirements of different types of power batteries can be met by adjusting the doping amount of graphene quantum dots and functional fillers; the thermally conductive integrated layer is composed of a second fiber substrate and a plurality of metal thermally conductive elements embedded in its first surface.

2. The general-purpose composite thermal insulation material according to claim 1, characterized in that, The first fiber substrate is a hollow pre-oxidized fiber needle-punched felt; wherein the fiber diameter of the needle-punched felt is 3~12μm, the hollowness is 20~55%, and the needle-punching density is 10~40 needles / cm. 2 The surface density is 50~120 g / m³ 2 ; and / or The hydrophobic sealing layer is a polytetrafluoroethylene film, and the thickness of the hydrophobic sealing layer is 2~10μm.

3. The general-purpose composite thermal insulation material according to claim 1, characterized in that, The functional filler includes at least one of flame-retardant filler, thermally conductive filler, or electrically conductive filler; Preferably, the flame-retardant filler is magnesium hydroxide particles; the thermally conductive filler is at least one of nano-alumina or boron nitride microplates; and the conductive filler is carbon nanotubes. More preferably, the doping amount of the functional filler is 0~5wt%; and / or The doping amount of the graphene quantum dots is 2~10wt%.

4. The general-purpose composite thermal insulation material according to claim 1 or 3, characterized in that, For ternary lithium batteries, the graphene quantum dot content in the modular thermal insulation interlayer is 4~6 wt%; For aluminum iron phosphate batteries, the doping amount of graphene quantum dots in the modular thermal insulation interlayer is 6~8wt%, and the doping amount of functional fillers is 1~5wt%. For sodium-ion batteries, the doping amount of graphene quantum dots in the modular heat insulation interlayer is 2~4wt%, and the doping amount of functional fillers is 1~3wt%.

5. The general-purpose composite thermal insulation material according to claim 1, characterized in that, The second fiber substrate is a dense pre-oxidized fiber needle-punched felt; wherein the fiber diameter of the needle-punched felt is 2~5μm, and the needle-punching density is 20~30 needles / cm. 2 The surface density is 50~80 g / m³ 2 .

6. The general-purpose composite thermal insulation material according to claim 1, characterized in that, The metal heat-conducting element is a copper foil strip; wherein each copper foil strip has a thickness of 0.05~0.2mm, a width of 0.5~2mm, and a spacing of 5~15mm between two adjacent copper foil strips; Preferably, the copper foil strip is embedded along the length of the first surface of the second fiber substrate, and both ends extend to the edge of the second fiber substrate to form a standard snap or laser welding interface to achieve docking with the battery pack heat sink or PTC heater.

7. The general-purpose composite thermal insulation material according to claim 6, characterized in that, The second surface of the second fiber substrate is provided with a microgroove array to achieve mechanical interlocking between the thermally conductive integrated layer and the modular thermal insulation interlayer; and / or The microgroove array is formed by a number of V-shaped microgrooves extending continuously on the surface of the second fiber substrate; wherein the depth of each microgroove is 10~30μm.

8. The general-purpose composite thermal insulation material according to claim 7, characterized in that, The extension direction of each microgroove on the second surface forms an angle greater than 0 with the extension direction of the metal heat-conducting element disposed on the first surface; the angle is preferably 30°~60°.

9. The general-purpose composite thermal insulation material according to claim 1, characterized in that, At least one support strip is provided between the thermally conductive integrated layer and the protective hydrophobic layer for adjusting the spacing between the thermally conductive integrated layer and the protective hydrophobic layer; Each support bar has anchoring structures at both ends to mechanically interlock with the thermally conductive integrated layer and the protective hydrophobic layer, respectively; and / or The support strip is made of para-aramid 1313, polyimide fiber, or pre-oxidized silicone rubber composite fiber; the length of the support strip is 2-5 mm, and the spacing between two adjacent support strips is 20-40 mm.

10. A method for preparing a universal composite thermal insulation material adaptable to multiple types of power batteries according to any one of claims 1 to 9, characterized in that, The preparation method includes the following steps: (1) A hydrophobic slurry is sprayed onto the surface of the first fiber substrate and dried to form a hydrophobic sealing layer on the surface of the first fiber substrate, thereby obtaining a protective hydrophobic layer. (2) A metal thermally conductive element is embedded along the first surface of the second fiber substrate using an embedded injection molding process, and a micro-groove array is set on the second surface of the second fiber substrate using a press to obtain a thermally conductive integrated layer; (3) According to the customized requirements of different types of power batteries, graphene quantum dots, functional fillers and silica precursor sol are mixed to obtain a mixed sol. At least one support strip is provided between the protective hydrophobic layer and the thermally conductive integrated layer to fix the thermally conductive integrated layer and the protective hydrophobic layer and form a cavity between them. The mixed sol is pressure injected into the cavity, and after passing through sol-gel, aging treatment and supercritical drying treatment in sequence, the general-purpose composite heat insulation material adapted to multiple types of power batteries is obtained.

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