Composite material, heat absorbing member, battery assembly and electric device

Abstract

The present application provides a composite material, a heat absorbing member, a battery assembly, and an electric device. The composite material comprises a polymer framework, an inorganic additive, and a phase change component. The inorganic additive comprises at least one of a hydrophilic aerogel and kaolin. In the composite material of the present application, the phase change component can improve the heat absorption performance of the composite material, and the inorganic additive can improve the thermal insulation performance of the composite material, such that the composite material has excellent heat absorption and thermal insulation effects, facilitating the use of the composite material in a battery assembly, and improving the use safety of battery cells.

Description

Composite materials, heat absorbers, battery modules and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 202411203975.4, filed on August 29, 2024, entitled "Composite Materials, Heat Absorbers, Battery Components and Electrical Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to composite materials, heat absorbers, battery modules, and electrical equipment. Background Technology

[0003] Batteries provide power for electrical devices, and temperature changes during battery use affect the performance and safety of both the battery and the device. Currently, thermal insulation materials are used to reduce heat transfer between adjacent batteries; however, batteries can experience thermal runaway due to physical damage or other reasons. When a battery experiences thermal runaway, it generates a large amount of heat, and thermal insulation materials often fail to effectively prevent this heat transfer to adjacent batteries, thus compromising the safety of the electrical device. Summary of the Invention

[0004] In view of this, this application provides a composite material, a heat absorber, a battery assembly, and an electrical device.

[0005] In a first aspect, this application provides a composite material comprising a polymer skeleton, inorganic additives, and a phase change component, wherein the inorganic additives include at least one of hydrophilic aerogel and kaolin.

[0006] Optionally, the hydrophilic aerogel includes at least one of hydrophilic silica aerogel, hydrophilic alumina aerogel, hydrophilic carbon aerogel, and hydrophilic nitride aerogel.

[0007] Optionally, the hydrophilic aerogel has a pore size of 1 nm-500 nm and a porosity of 80%-99.8%.

[0008] Optionally, the particle size Dv50 of the hydrophilic aerogel is 0.5 μm-20 μm.

[0009] Optionally, the content of the inorganic additive in the composite material is 0.1 wt% to 10 wt%.

[0010] Optionally, the polymer skeleton has a pore size of 1μm-700μm and a porosity of 60%-90%.

[0011] Optionally, the polymer backbone may be made of at least one of polyacrylamide, sodium polyacrylate, polyacrylic acid, polymethacrylic acid, polyethylene glycol, and polyvinyl alcohol.

[0012] Optionally, the content of the polymer backbone in the composite material is 1wt%-15wt%.

[0013] Optionally, the composite material may further include at least one of a tackifier, a bactericide, and an antifreeze agent.

[0014] Optionally, the thickener includes at least one of carboxymethyl cellulose, guar gum, and carbomer.

[0015] Optionally, the bactericide includes at least one of polyquaternium salt, gold nifedipine, and biguanide salt.

[0016] Optionally, the antifreeze includes at least one of an organic solvent and an inorganic salt, wherein the organic solvent includes at least one of ethylene glycol and glycerol, and the inorganic salt includes at least one of sodium chloride, calcium chloride, and zinc chloride.

[0017] Optionally, the content of the tackifier in the composite material is 0.05wt%-20wt%.

[0018] Optionally, the content of the bactericide in the composite material is 0.01wt%-5wt%.

[0019] Optionally, the content of the antifreeze in the composite material is 1wt%-20wt%.

[0020] Optionally, the content of the phase change component in the composite material is greater than or equal to 70 wt%.

[0021] Optionally, the phase change component includes at least one of water, butanol, ethyl acetate, acetic acid, and propionic acid.

[0022] Secondly, this application provides a heat-absorbing element comprising the composite material described in the first aspect.

[0023] Optionally, the heat-absorbing element further includes an encapsulation structure, the encapsulation structure having an accommodating space inside, and the composite material disposed in the accommodating space.

[0024] Optionally, the material of the encapsulation structure includes at least one of plastic and metal.

[0025] Optionally, the heat-absorbing element further includes a carrier skeleton, which has a sheet-like structure and multiple pores filled with the composite material.

[0026] Optionally, the thickness of the carrier skeleton is 0.05mm-2mm, and the diameter of the holes is 0.5mm-20mm.

[0027] Thirdly, this application provides a battery assembly, the battery assembly including a battery cell and the heat-absorbing element described in the second aspect, the heat-absorbing element being disposed on the surface of the battery cell.

[0028] Fourthly, this application provides an electrical device including the battery assembly described in the third aspect.

[0029] The phase change component in the composite material of this application can improve the heat absorption performance of the composite material, and the inorganic additives can improve the heat insulation performance of the composite material, so that the composite material has excellent heat absorption and heat insulation effects. Moreover, the preparation method of the composite material is simple, which is conducive to the use of the composite material in battery modules and improves the safety of battery cell use. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0031] Figure 1 is a cross-sectional schematic diagram of a heat-absorbing element provided in one embodiment of this application;

[0032] Figure 2 is a cross-sectional schematic diagram of a battery assembly provided in one embodiment of this application;

[0033] Figure 3 is a cross-sectional schematic diagram of a battery assembly provided in another embodiment of this application;

[0034] Figure 4 shows the infrared spectrum of the composite material obtained in Example 1. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0036] This application provides a composite material comprising a polymer backbone, inorganic additives, and a phase change component. The inorganic additives include at least one of hydrophilic aerogel and kaolin. During the phase change process, the phase change component in the composite material can absorb a large amount of heat, while the inorganic additives provide excellent thermal insulation, preventing heat transfer. This allows the composite material to both absorb external heat and block heat transfer. Furthermore, the inorganic additives enhance the composite material's ability to retain the phase change component, promoting its long-term use and thus its application in battery modules, improving the safety of the battery cells.

[0037] Composite materials rely on phase change components to absorb heat during the phase change process, ensuring their heat absorption performance. In one embodiment of this application, the phase change component includes at least one of water and a hydrophilic material. When the inorganic additive includes a hydrophilic aerogel, the affinity between the inorganic additive and the phase change component is better, which can improve the stability of the phase change component, reduce the loss of the phase change component in the composite material, and thus improve the performance of the composite material. In one embodiment of this application, the phase change component includes at least one of water, butanol, ethyl acetate, acetic acid, and propionic acid. The above-mentioned phase change components can absorb heat during the phase change process, ensuring the heat absorption performance of the composite material. In one embodiment of this application, the phase change component may include water. Water has a large latent heat of vaporization and can absorb a large amount of heat, giving the composite material better heat absorption performance. In one embodiment of this application, the composite material is a hydrogel. The hydrogel can contain and retain a large amount of water, improving the heat absorption performance of the composite material.

[0038] In one embodiment of this application, the content of the phase change component in the composite material is greater than or equal to 70 wt%, which is beneficial to improving the heat absorption performance of the composite material. Specifically, the content of the phase change component in the composite material can be, but is not limited to, 70 wt% or more, 72 wt% or more, 75 wt% or more, 77 wt% or more, 78 wt% or more, 80 wt% or more, 81 wt% or more, 82 wt% or more, 85 wt% or more, 88 wt% or more, 90 wt% or more, 91 wt% or more, 92 wt% or more, or 94 wt% or more. In one embodiment of this application, the content of the phase change component in the composite material is 70 wt%-95 wt%, which ensures both the content of the phase change component and the content of other components in the composite material, which is beneficial to further improving the performance of the composite material. Specifically, the content of phase change components in composite materials can be, but is not limited to, 70wt%, 72wt%, 73wt%, 75wt%, 77wt%, 80wt%, 82wt%, 84wt%, 85wt%, 86wt%, 88wt%, 90wt%, 91wt%, 93wt%, 94wt%, or 95wt%.

[0039] In composite materials, the polymer skeleton serves to load phase change components and inorganic additives, ensuring the content of phase change components and thus guaranteeing the heat absorption performance of the composite material. Furthermore, the excellent flexibility of the polymer skeleton enhances the compressive strength of the composite material. Specifically, the phase change component is loaded into the polymer skeleton before the phase change occurs. After undergoing a phase change upon heating, the phase change component detaches from the polymer skeleton, absorbing heat in the process. Upon cooling, the phase change component is reloaded into the polymer skeleton, thereby achieving a continuous and stable heat absorption effect in the composite material. For example, when the phase change component is water, the polymer skeleton can load liquid water. When the liquid water absorbs heat and changes to a gaseous state, it can detach from the polymer skeleton. When the gaseous water cools and becomes liquid again, it can be reloaded into the polymer skeleton, ensuring the heat absorption performance and cooling effect of the composite material.

[0040] In one embodiment of this application, the polymer backbone has a three-dimensional network structure, and the phase change component is dispersed and loaded in the three-dimensional network structure of the polymer backbone.

[0041] In one embodiment of this application, the content of the polymer backbone in the composite material is 1wt%-15wt%, which is beneficial for both the loading of the phase change component and ensuring the flexibility and strength of the composite material, thereby improving its performance. Specifically, the content of the polymer backbone in the composite material can be, but is not limited to, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt%.

[0042] In one embodiment of this application, the polymer backbone is made of at least one of polyacrylamide, sodium polyacrylate, polyacrylic acid, polymethacrylic acid, polyethylene glycol, and polyvinyl alcohol. In another embodiment, the polymer backbone is made of polyacrylamide and sodium polyacrylate. The polyacrylamide and sodium polyacrylate form an interpenetrating network structure, further improving the flexibility, strength, and ability to load phase change components of the polymer backbone. In yet another embodiment, the polymer backbone is made of polyacrylamide, sodium polyacrylate, and polyacrylic acid, which is beneficial for further improving the structural stability of the polymer backbone.

[0043] In one embodiment of this application, the polymer backbone has hydrophilic groups, which can improve the loading and retention capacity of phase change components, thereby helping to improve the heat absorption performance of the composite material. Furthermore, when the inorganic additive includes a hydrophilic aerogel, the hydrophilic aerogel can directly contact and connect with the polymer backbone, which is beneficial for the uniform dispersion and loading of the inorganic additive in the polymer backbone, thus helping to improve the uniform thermal insulation performance of the composite material. In one embodiment of this application, the hydrophilic groups include at least one of amide, amino, hydroxyl, and carboxyl groups.

[0044] In one embodiment of this application, the pore size of the polymer skeleton is 1μm-700μm, and the porosity is 60%-90%, which is beneficial for loading more phase change components and improving the ability to retain phase change components. Specifically, the pore size of the polymer skeleton can be, but is not limited to, 1μm, 10μm, 30μm, 50μm, 80μm, 100μm, 135μm, 150μm, 180μm, 200μm, 250μm, 300μm, 350μm, 400μm, 500μm, 550μm, 600μm, 650μm, or 700μm; the porosity of the polymer skeleton can be, but is not limited to, 60%, 65%, 68%, 70%, 73%, 75%, 80%, 85%, 88%, or 90%. In this application, the polymer skeleton is tested after the composite material is freeze-dried to obtain its pore size and porosity. The pore size is the average pore size. The average value of all pore sizes in the field of view of the polymer skeleton within a length of 2 mm and a width of 2 mm is defined as the skeleton pore size. For example, the pore size of the polymer skeleton can be obtained by scanning electron microscopy (SEM). In addition, the porosity of the polymer skeleton can be obtained by testing the mass and volume changes of the hydrogel before and after freeze-drying using the liquid substitution method.

[0045] The composite material contains inorganic additives, including at least one of hydrophilic aerogel and kaolin. These inorganic additives have excellent thermal insulation effects, allowing the phase change component to absorb external heat and reduce heat transfer, while the inorganic additives act as thermal insulators, further hindering heat transfer and improving the thermal insulation effect of the composite material. Inorganic additives can also improve the strength of the composite material. At the same time, inorganic additives can improve the composite material's ability to retain phase change components, so that the composite material can contain a high level of phase change components before and after aging tests, improving the composite material's anti-aging ability and benefiting its use.

[0046] In one embodiment of this application, the content of inorganic additives in the composite material is 0.1wt%-10wt%, which can improve the thermal insulation effect of the composite material while ensuring its heat absorption performance, thereby enabling the composite material to effectively impede heat transfer. Specifically, the content of inorganic additives in the composite material can be, but is not limited to, 0.1wt%, 0.5wt%, 0.7wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, or 10wt%. In one embodiment of this application, the content of inorganic additives in the composite material can be 0.1wt%-5wt%.

[0047] In one embodiment of this application, the thermal conductivity of the hydrophilic aerogel is less than or equal to 0.02 W / (m·K), thereby further improving the thermal insulation effect of the composite material. In another embodiment, the hydrophilic aerogel includes at least one of hydrophilic silica aerogel, hydrophilic alumina aerogel, hydrophilic carbon aerogel, and hydrophilic nitride aerogel. The aforementioned hydrophilic aerogels have excellent thermal insulation effects, which can further improve the thermal insulation effect of the composite material, especially reducing heat transfer between thermally runaway cells and improving the safety of the battery assembly. In one embodiment of this application, the hydrophilic aerogel includes hydrophilic silica aerogel, which can effectively improve the thermal insulation effect of the composite material. In this application, the hydrophilic aerogel can be obtained by modifying the aerogel (e.g., grafting hydrophilic groups such as amide, amino, hydroxyl, and carboxyl groups), or it can be purchased directly, or the aerogel itself can be hydrophilic. Specifically, the hydrophilicity of aerogel can be determined by how well it disperses in water. For example, mix 15g of aerogel with 100g of water and let it stand for 5 hours. If the aerogel can be evenly dispersed in water, it is considered a hydrophilic aerogel. If the aerogel separates into layers in water, it is considered a hydrophobic aerogel.

[0048] In one embodiment of this application, the pore size of the hydrophilic aerogel is 1nm-500nm, and the porosity is 80%-99.8%, which is beneficial to further improve the thermal insulation performance of the hydrophilic aerogel, thereby improving the thermal insulation effect of the composite material. Specifically, the pore size of the hydrophilic aerogel can be, but is not limited to, 1nm, 8nm, 10nm, 15nm, 20nm, 30nm, 35nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, or 500nm, etc.; the porosity of the hydrophilic aerogel can be, but is not limited to, 80%, 82%, 85%, 87%, 89%, 90%, 93%, 95%, 96%, 98%, or 99%, etc. The pore size of hydrophilic aerogels can be obtained using a specific surface area and pore size analyzer, and the porosity of hydrophilic aerogels can be obtained using a nitrogen adsorption method.

[0049] In one embodiment of this application, the particle size Dv50 of the hydrophilic aerogel is 0.5 μm-20 μm. Specifically, the particle size Dv50 of the hydrophilic aerogel can be, but is not limited to, 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 17 μm, 19 μm, or 20 μm. The particle size Dv50 of the hydrophilic aerogel can be measured by scanning electron microscopy (SEM).

[0050] In one embodiment of this application, the composite material further includes at least one of a tackifier, a bactericide, and an antifreeze agent. The tackifier helps increase the viscosity of the composite material, which is beneficial for its use; the bactericide improves the antibacterial effect of the composite material, which helps broaden its application scenarios; and the antifreeze agent can improve the antifreeze effect of the composite material, thereby enhancing its performance.

[0051] In one embodiment of this application, the content of the tackifier in the composite material is 0.05wt%-20wt%, which is beneficial to increasing the content of phase change components in the composite material and improving the heat absorption performance of the composite material. Specifically, the content of the tackifier in the composite material can be, but is not limited to, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%. In one embodiment of this application, the tackifier includes at least one of carboxymethyl cellulose, guar gum, and carbomer.

[0052] In one embodiment of this application, the content of the bactericide in the composite material is 0.01wt%-5wt%, which can improve the antibacterial effect of the composite material while ensuring the content of the phase change component and the heat absorption performance of the composite material. Specifically, the content of the bactericide in the composite material can be, but is not limited to, 0.01wt%, 0.02wt%, 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, or 5wt%. In one embodiment of this application, the content of the bactericide in the composite material can be 0.02wt%-5wt%. In one embodiment of this application, the bactericide includes at least one selected from polyquaternary ammonium salt, gold nifedipine, and biguanide salt. Specifically, the polyquaternium salt may include at least one of polyquaternium salt-51 and polyquaternium salt-15, the gold ester of paraben may include at least one of methylparaben, ethylparaben and propylparaben, and the biguanide salt may include at least one of polyhexamethylene biguanide salt and polyaminopropyl biguanide salt.

[0053] When the phase change component of the composite material in this application is water, the water will turn into ice at low temperatures, especially below zero temperatures, causing the volume of water and composite material to increase. The addition of antifreeze increases the distance between water molecules, making it difficult to form ice crystals and inhibiting the continued expansion of ice crystals, thereby inhibiting and slowing down the formation of ice, thus improving the antifreeze effect of the composite material. This allows the composite material to avoid the compression caused by volume expansion when used under low temperature conditions, thereby improving the safety of the composite material in use.

[0054] In one embodiment of this application, the antifreeze content in the composite material is 1wt%-20wt%, which can improve the antifreeze ability of the composite material, broaden its application scenarios, and ensure the content of phase change components in the composite material, thus guaranteeing the heat absorption performance of the composite material. Specifically, the content of antifreeze in the composite material can be, but is not limited to, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%. In one embodiment of this application, the antifreeze content in the composite material can be 1wt%-20wt%, which can improve the antifreeze ability of the composite material without affecting the content of phase change components in the composite material, ensuring the phase change enthalpy, and thus guaranteeing the heat absorption performance of the composite material. In one embodiment of this application, the antifreeze agent includes at least one selected from an organic solvent and an inorganic salt. The organic solvent includes at least one selected from ethylene glycol and glycerol, and the inorganic salt includes at least one selected from sodium chloride, calcium chloride, and zinc chloride. In another embodiment of this application, the antifreeze agent includes at least one selected from ethylene glycol and glycerol, and the phase change component is water. Ethylene glycol and glycerol can form hydrogen bonds with water, inhibiting water evaporation and improving the water retention capacity of the composite material, which is beneficial for the use of the composite material. In one embodiment of this application, the content of ethylene glycol in the composite material can be less than or equal to 10 wt%. In another embodiment of this application, the content of glycerol in the composite material can be 1 wt% to 20 wt%.

[0055] In one embodiment of this application, the composite material may further include an antibacterial agent, giving the composite material an antibacterial effect and facilitating its use. The antibacterial agent may be, but is not limited to, amphoteric organic ions, such as betaine or proline.

[0056] In one embodiment of this application, the surface of the composite material is hydrophilic, which is beneficial for the loading of phase change materials and inorganic additives, improves the overall stability of the composite material, and thus enhances the heat absorption and insulation effects of the composite material. Specifically, the contact angle of the composite material surface can be measured using a contact angle measuring instrument. When the contact angle is less than 90°, it indicates that the surface of the composite material is hydrophilic.

[0057] In one embodiment of this application, the composite material comprises 1 wt%-15 wt% of a polymer backbone, 0.1 wt%-10 wt% of inorganic additives, and a phase change component. In another embodiment of this application, the composite material comprises 1 wt%-15 wt% of a polymer backbone, 0.1 wt%-10 wt% of inorganic additives, 0.05 wt%-20 wt% of a tackifier, 0.01 wt%-5 wt% of a bactericide, 1 wt%-20 wt% of an antifreeze agent, and a phase change component. In yet another embodiment of this application, the composite material comprises 1 wt%-15 wt% of a polymer backbone, 0.1 wt%-10 wt% of inorganic additives, 0.05 wt%-20 wt% of a tackifier, 0.01 wt%-5 wt% of a bactericide, 1 wt%-20 wt% of an antifreeze agent, and 70 wt%-95 wt% of a phase change component.

[0058] This application provides a method for preparing a composite material, comprising mixing a monomer, a phase change component, an inorganic additive, a crosslinking agent, and an initiator to form a mixture, and then reacting the mixture to obtain a composite material. This preparation method can produce the composite material described in any of the above embodiments. The method is simple to operate, has low preparation cost, is beneficial for the industrial production of composite materials, and facilitates the application of composite materials.

[0059] In this application, monomers form a polymer skeleton in the composite material under the action of crosslinking agents and initiators, which is used to load phase change components, inorganic additives, etc. In one embodiment of this application, the monomer includes at least one of acrylamide and sodium acrylate. Thus, a polymer skeleton formed from at least one of polyacrylamide and sodium polyacrylate can be formed after the reaction. Among them, the sodium polyacrylate skeleton formed by sodium acrylate can further increase the content of phase change components in the composite material and the ability of the composite material to retain phase change components, thereby further improving the heat absorption performance. In another embodiment of this application, the monomer also includes acrylic acid. Thus, the polymer skeleton contains polyacrylic acid. In one embodiment of this application, the content of monomer in the mixture is 1wt%-15wt%, which is beneficial to ensure the content of polymer skeleton in the composite material, thereby increasing the content of phase change components in the composite material and improving the heat absorption effect of the composite material. Specifically, the content of monomer in the mixture can be, but is not limited to, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt%, etc. In one embodiment of this application, the content of acrylamide in the mixture can be 1 wt%-5 wt%. In one embodiment of this application, the content of sodium acrylate in the mixture can be 1 wt%-15 wt%. In one embodiment of this application, the content of acrylic acid in the mixture is less than or equal to 10 wt%.

[0060] In this application, the crosslinking agent enables monomers to crosslink, which is beneficial for the formation of a three-dimensional network structure, thereby forming a polymer skeleton capable of loading phase change components and inorganic additives. Simultaneously, the crosslinking agent helps increase the crosslinking density of the polymer skeleton, thereby enhancing its strength and ensuring that the polymer skeleton retains its original gel state after aging tests, thus improving the mechanical properties and anti-aging properties of the composite material. In one embodiment of this application, the crosslinking agent includes N,N-methylenebisacrylamide. In another embodiment of this application, the content of the crosslinking agent in the mixture is 0.015wt%-0.2wt%, ensuring both crosslinking efficiency and the performance of the formed polymer skeleton, which is beneficial for the use of the composite material. Specifically, the content of the crosslinking agent in the mixture can be, but is not limited to, 0.015wt%, 0.03wt%, 0.05wt%, 0.07wt%, 0.08wt%, 0.1wt%, 0.13wt%, 0.15wt%, 0.18wt%, or 0.2wt%, etc.

[0061] In this application, the initiator can generate free radicals during the reaction. Under the action of free radicals, the monomers can polymerize, which is beneficial to the formation of the polymer skeleton. In one embodiment of this application, the initiator includes at least one of azobisisobutyramidine hydrochloride and ammonium persulfate. The above-mentioned initiator has good water solubility and is suitable for the preparation of composite materials in which the phase change component is water. In one embodiment of this application, the content of the initiator in the mixture is 0.015wt%-0.2wt%, which ensures both polymerization efficiency and the flexibility of the formed polymer skeleton, thereby improving the performance of the composite material. Specifically, the content of the initiator in the mixture can be, but is not limited to, 0.015wt%, 0.03wt%, 0.05wt%, 0.07wt%, 0.08wt%, 0.1wt%, 0.13wt%, 0.15wt%, 0.18wt%, or 0.2wt%, etc.

[0062] In this application, inorganic additives can increase the reaction rate, accelerate the formation of composite materials, and improve the strength and anti-aging properties of the composite materials, while also enhancing their thermal insulation effect, thus obtaining composite materials with excellent comprehensive performance. The inorganic additives and crosslinking agents can work synergistically to improve the strength and anti-aging properties of the composite materials. The selection of inorganic additive materials is as described above and will not be repeated here. In one embodiment of this application, the content of inorganic additives in the mixture is 0.1wt%-10wt%. Specifically, the content of inorganic additives in the mixture can be, but is not limited to, 0.1wt%, 0.5wt%, 0.7wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, or 10wt%. In one embodiment of this application, the content of inorganic additives in the mixture can be 0.1wt%-5wt%.

[0063] In this application, the phase change component can be dispersed and loaded within the polymer backbone formed by the monomers. The phase change component absorbs external heat through phase change, ensuring the heat absorption effect of the composite material. In one embodiment of this application, the content of the phase change component in the mixture is greater than or equal to 70 wt%. In another embodiment of this application, the content of the phase change component in the composite material can be 70 wt%-95 wt%.

[0064] In one embodiment of this application, the mixture further includes at least one of a thickener, a bactericide, and an antifreeze agent. The selection of the thickener, bactericide, and antifreeze agent materials is as described above and will not be repeated here. The thickener can increase the viscosity of the mixture, thereby increasing the reaction rate, and also helps to increase the content of the phase change component in the composite material. The thickener and monomer (especially sodium acrylate) can work synergistically to increase the content of the phase change component in the composite material, thereby improving the heat absorption performance of the composite material and its ability to retain the phase change component, resulting in better heat absorption stability of the composite material. In one embodiment of this application, the content of the thickener in the mixture is less than or equal to 20 wt%. Specifically, the content of the thickener in the mixture can be, but is not limited to, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%. In one embodiment of this application, the thickener in the mixture can be 0.05 wt% to 20 wt%. In one embodiment of this application, the content of the bactericide in the mixture is less than or equal to 5 wt%. Specifically, the content of the bactericide in the mixture can be, but is not limited to, 0.02 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%. In one embodiment of this application, the content of the bactericide in the mixture can be 0.01 wt% to 5 wt%. In one embodiment of this application, the content of the antifreeze in the mixture is less than or equal to 20 wt%. Specifically, the content of the antifreeze in the mixture can be, but is not limited to, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt%. In one embodiment of this application, the content of the antifreeze in the mixture can be 1 wt% to 5 wt%.

[0065] In one embodiment of this application, monomers and inorganic additives can be dispersed in water, and a crosslinking agent and an initiator can be added to react and form a composite material; in this case, the composite material is a hydrogel. In another embodiment of this application, monomers, thickeners, bactericides, antifreeze agents, and inorganic additives can be dispersed in water, and a crosslinking agent and an initiator can be added to react and form a composite material; in this case, the composite material is a hydrogel.

[0066] In one embodiment of this application, the reaction temperature is 20℃-60℃, and the reaction time is 5min-240min, which is beneficial for cross-linking polymerization and the formation of a composite material with excellent performance. Specifically, the reaction temperature can be, but is not limited to, 20℃, 25℃, 20℃, 35℃, 40℃, 45℃, 50℃, 55℃, or 60℃, and the reaction time can be, but is not limited to, 5min, 20min, 60min, 120min, 150min, 180min, 200min, or 240min.

[0067] This application provides a heat-absorbing component, comprising the composite material described in any of the above embodiments. The heat-absorbing component with this composite material exhibits excellent heat absorption and insulation properties, which is beneficial for its use.

[0068] Please refer to Figure 1, which is a cross-sectional schematic diagram of a heat-absorbing component provided in one embodiment of this application. The heat-absorbing component 100 includes an encapsulation structure 10 and a composite material 20. The encapsulation structure 10 has an internal accommodating space 11, and the composite material 20 is disposed in the accommodating space 11. By encapsulating the composite material in the encapsulation structure, direct contact between the composite material and products such as battery cells is further avoided, thereby preventing problems such as short circuits, improving the safety and service life of the heat-absorbing component, and the encapsulation structure can fix and restrict the composite material, further improving the mechanical properties of the heat-absorbing component.

[0069] In one embodiment of this application, the ratio of the volume of the composite material to the volume of the accommodating space is 50%-70%. This ensures the content of the composite material in the heat-absorbing component, thereby guaranteeing the heat absorption performance of the heat-absorbing structure. Simultaneously, it reserves space for the phase change of the phase change components in the composite material during heat absorption, which is beneficial for heat transfer, thus achieving better heat absorption and improving the service life of the heat-absorbing component. Specifically, the ratio of the volume of the composite material to the volume of the accommodating space can be, but is not limited to, 50%, 52%, 55%, 58%, 59%, 60%, 61%, 63%, 65%, 67%, 68%, or 70%, etc.

[0070] The dimensions of the composite material in the heat absorber of this application can be set according to the usage requirements of the heat absorber. In one embodiment of this application, the thickness of the composite material can be 0.3mm-15mm, which can ensure the heat absorption performance of the heat absorber without excessively increasing the weight and volume of the heat absorber, thus facilitating its use.

[0071] The encapsulation structure in the heat absorber serves to seal and house the heat absorber. In one embodiment of this application, the encapsulation structure is made of at least one material, including plastic and metal. These materials are relatively thin and lightweight, offer good moisture barrier properties and sealing performance, which is beneficial for the use of the heat absorber. The plastic can be, but is not limited to, polyethylene terephthalate, and the metal can be, but is not limited to, aluminum. In one embodiment of this application, the encapsulation structure can be an aluminum-plastic film. The aluminum-plastic film is a composite structure comprising aluminum foil and a plastic film. In this application, the size of the encapsulation structure can be selected according to the size of the battery cell so that the heat absorber can match the battery cell, improving the heat absorption efficiency of the heat absorber. In one embodiment of this application, a mixture forming a composite material can be placed inside the encapsulation film, reacting to form a composite material. Sealing the encapsulation film then forms the encapsulation structure, resulting in the heat absorber. Furthermore, sterilization treatment can be performed after sealing to improve the performance of the heat absorber.

[0072] In one embodiment of this application, the heat-absorbing component further includes a carrier skeleton. The carrier skeleton has a sheet-like structure and multiple holes filled with composite material. The carrier skeleton can support, fix, and restrict the composite material, thereby improving the mechanical properties of the heat-absorbing component. The carrier skeleton has multiple holes filled with composite material, which can fill all or some of the holes. The opening shape of the holes can be, but is not limited to, polygons (such as squares, rectangles, hexagons, octagons, rhombuses, triangles, etc.), circles, ellipses, semicircles, irregular shapes, etc., and can be selected as needed. In one embodiment of this application, the holes penetrate the carrier skeleton along its thickness direction. That is, the holes are through holes, which is beneficial for the filling and dispersion of the composite material. In another embodiment of this application, the holes do not penetrate the carrier skeleton along its thickness direction. That is, the holes are blind holes, which is beneficial for loading the composite material. In this application, the holes in the carrier skeleton can be through holes, blind holes, or partially through holes and partially blind holes. In one embodiment of this application, all the holes penetrate the carrier skeleton along its thickness direction. In another embodiment of this application, the holes uniformly penetrate the carrier skeleton along its thickness direction. That is, along the thickness direction of the carrier skeleton, the holes have the same diameter on a cross-section perpendicular to the thickness direction of the carrier skeleton, which is beneficial for the uniform filling of the composite material in the carrier skeleton and for improving the overall support performance of the carrier skeleton. In one embodiment of this application, the material of the carrier skeleton may be, but is not limited to, at least one of polyester, polypropylene, and glass fiber, and the carrier skeleton made of the above materials has better support performance and mechanical properties. In one embodiment of this application, the carrier skeleton is disposed in the accommodating space of the encapsulation structure. In some embodiments, the carrier skeleton can be placed inside the encapsulation film, and then a mixture for forming the composite material can be added. After reaction, the composite material is formed, and the encapsulation film is sealed to form an encapsulation structure, thus obtaining a heat-absorbing element.

[0073] In one embodiment of this application, the thickness of the carrier skeleton is 0.05mm-2mm, and the diameter of the holes is 0.5mm-20mm, which is beneficial for supporting the composite material and its load-bearing capacity. Specifically, the thickness of the carrier skeleton can be, but is not limited to, 0.05mm, 0.08mm, 0.1mm, 0.15mm, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.5mm, 1.7mm, or 2mm, etc.; the diameter of the holes can be, but is not limited to, 0.5mm, 1mm, 3mm, 5mm, 7mm, 10mm, 12mm, 14mm, 16mm, 19mm, or 20mm, etc. The average value of all hole diameters within a 2cm long and 2cm wide field of view of the carrier skeleton is defined as the hole diameter.

[0074] This application provides a battery assembly, including a battery cell and a heat-absorbing element as described in any of the above embodiments, wherein the heat-absorbing element is disposed on the surface of the battery cell. The composite material in the heat-absorbing element can absorb the heat generated by the battery cell using its heat-absorbing properties, giving the battery cell a better heat dissipation effect. It can also block the transfer of heat between battery cells. Especially in the event of thermal runaway, the heat-absorbing element can play an excellent role in heat insulation, reducing the severity of thermal runaway and improving the safety of the battery assembly. In this application, the heat-absorbing element can be directly or indirectly attached to the battery cell, and the battery assembly can be a battery pack or a battery module.

[0075] The number of cells in a battery assembly can be selected according to usage requirements, such as one, two, three, four, seven, ten, etc. Referring to Figure 2, a cross-sectional schematic diagram of a battery assembly according to one embodiment of this application, the battery assembly 300 includes a cell 200 and a heat absorber 100, the heat absorber 100 being disposed on the surface of the cell 200, and the battery assembly 300 having one cell 200. Referring to Figure 3, a cross-sectional schematic diagram of a battery assembly according to another embodiment of this application, the battery assembly 300 includes multiple cells 200 and heat absorbers 100, the heat absorbers 100 being disposed between two adjacent cells 200. This increases the heat absorption efficiency of the heat absorber, further improving the operational safety of the battery assembly. It is understood that along the stacking direction of the cells and heat absorbers, the outermost part of the battery assembly can be either a cell or a heat absorber, and this is not limited.

[0076] This application provides an electrical device including the battery module described in any of the above embodiments. The electrical device provided by this application boasts excellent performance and lifespan, making it highly competitive. Specifically, the electrical device can refer to vehicles, electronic devices, energy storage systems, etc.

[0077] The effects of the technical solution in this application will be further illustrated below with specific examples.

[0078] Example 1

[0079] Acrylamide, ethylene glycol, glycerol, guar gum, hydrophilic silica aerogel powder (pore size 60 nm, porosity 90%, particle size Dv50 15 μm), polyquaternium salt, and water were mixed and stirred until homogeneous. Then, azobisisobutyramidine hydrochloride was added, and N,N-methylenebisacrylamide was added while stirring continuously to form a mixture (the content of azobisisobutyramidine hydrochloride in the mixture was 0.007 wt%, and the content of N,N-methylenebisacrylamide was 0.01 wt%). After reaction, a composite material was obtained, which included 4 wt% polyacrylamide, 0.5 wt% ethylene glycol, 3 wt% glycerol, 1 wt% guar gum, 1.5 wt% hydrophilic silica aerogel powder, 0.007 wt% polyquaternium salt, and 89.993 wt% water. The polyacrylamide had a pore size of 450 μm and a porosity of 85%.

[0080] The composite material prepared in Example 1 was analyzed using an infrared spectrometer. Figure 4 shows the infrared spectrum of the composite material prepared in Example 1, where 1651 cm⁻¹... -1 The peaks on the left and right are amide group (-CONH-) peaks, 3340 cm⁻¹. -1 The peaks on the left and right are -NH2 or H2O elution peaks, 1100 cm⁻¹. -1 The peaks on the left and right are C=O bond elution peaks. The contact angle of the composite material surface was measured to be 52° using a contact angle meter.

[0081] Example 2

[0082] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 4 wt% polyacrylamide, 0.5 wt% ethylene glycol, 1.5 wt% glycerol, 1 wt% guar gum, 3 wt% hydrophilic silica aerogel powder, 0.007 wt% polyquaternium salt and 89.993 wt% water. The pore size of the polyacrylamide is 385 μm and the porosity is 86%.

[0083] Example 3

[0084] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 4 wt% polyacrylamide, 0.5 wt% ethylene glycol, 1 wt% guar gum, 4.5 wt% hydrophilic silica aerogel powder, 0.007 wt% polyquaternium salt, and 89.993 wt% water. The polyacrylamide has a pore size of 420 μm and a porosity of 83%.

[0085] Example 4

[0086] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 6 wt% polyacrylamide, 1.5 wt% ethylene glycol, 4 wt% glycerol, 1.5 wt% hydrophilic silica aerogel powder, 0.007 wt% polyquaternium salt, and 86.993 wt% water. The pore size of the polyacrylamide is 490 μm and the porosity is 83%.

[0087] Example 5

[0088] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 7 wt% polyacrylamide, 2 wt% ethylene glycol, 2 wt% glycerol, 1 wt% guar gum, 1.5 wt% hydrophilic silica aerogel powder, 0.007 wt% polyquaternium salt and 86.493 wt% water. The pore size of the polyacrylamide is 480 μm and the porosity is 84%.

[0089] Example 6

[0090] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 12 wt% polyacrylamide, 0.5 wt% glycerol, 1 wt% guar gum, 5 wt% hydrophilic silica aerogel powder, 0.01 wt% polyquaternium salt and 81.49% water. The polyacrylamide has a pore size of 15 μm and a porosity of 72%.

[0091] Example 7

[0092] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 4 wt% polyacrylamide, 5 wt% ethylene glycol, 4 wt% glycerol, 1 wt% guar gum, 1 wt% hydrophilic silica aerogel powder, 0.007 wt% polyquaternium salt and 84.993% water. The pore size of the polyacrylamide is 650 μm and the porosity is 87%.

[0093] Example 8

[0094] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 4 wt% polyacrylamide, 9 wt% ethylene glycol, 5 wt% glycerol, 3 wt% guar gum, 0.007 wt% polyquaternium salt and 78.993% water. The polyacrylamide has a pore size of 780 μm and a porosity of 92%.

[0095] Example 9

[0096] The difference from Example 1 is that the content of each component in the mixture is changed. The resulting composite material includes 18 wt% polyacrylamide, 1 wt% guar gum, 7 wt% hydrophilic silica aerogel powder, 0.01 wt% polyquaternium salt and 73.99% water. The polyacrylamide has a pore size of 29 μm and a porosity of 52%.

[0097] Example 10

[0098] The difference from Example 1 is that the hydrophilic silica aerogel powder has a pore size of 53 nm, a porosity of 95%, and a particle size Dv50 of 18 μm.

[0099] Example 11

[0100] The difference from Example 1 is that the hydrophilic silica aerogel powder has a pore size of 42 nm, a porosity of 90%, and a particle size Dv50 of 16 μm.

[0101] Example 12

[0102] The difference from Example 1 is that the hydrophilic silica aerogel powder has a pore size of 12 nm, a porosity of 82%, and a particle size Dv50 of 17 μm.

[0103] Example 13

[0104] The difference from Example 1 is that the hydrophilic silica aerogel powder has a pore size of 450 nm, a porosity of 99%, and a particle size Dv50 of 14 μm.

[0105] Example 14

[0106] The difference from Example 1 is that the hydrophilic silica aerogel powder has a pore size of 600 nm, a porosity of 83%, and a particle size Dv50 of 16 μm.

[0107] Example 15

[0108] The difference from Example 1 is that the hydrophilic silica aerogel powder has a pore size of 26 nm, a porosity of 68%, and a particle size Dv50 of 13 μm.

[0109] Example 16

[0110] The difference from Example 1 is that sodium acrylate is used instead of acrylamide.

[0111] Example 17

[0112] The difference from Example 1 is that kaolin is used instead of hydrophilic silica aerogel powder.

[0113] Example 18

[0114] The difference from Example 1 is that ethylene glycol, glycerol, guar gum and polyquaternium salt are not added. The resulting composite material includes 6 wt% polyacrylamide, 2.5 wt% hydrophilic silica aerogel powder and 91.5 wt% water.

[0115] Comparative Example 1

[0116] The difference from Example 1 is that the content of each component in the mixture is changed, and the resulting composite material includes 4 wt% polyacrylamide, 0.5 wt% ethylene glycol, 4 wt% glycerol, 1.5 wt% guar gum, 0.007 wt% polyquaternium salt and 89.993 wt% water.

[0117] Comparative Example 2

[0118] The difference from Example 1 is that the hydrophilic silica aerogel powder is replaced with fumed silica powder (particle size Dv50 is 15 μm).

[0119] Comparative Example 3

[0120] The difference from Example 1 is that the hydrophilic silica aerogel powder is replaced with hydrophobic silica aerogel powder.

[0121] Performance testing

[0122] Aluminum-plastic film is folded into a bag shape using a machine. The bag is filled with plastic mesh as a carrier skeleton (0.1 mm thick, with 2 mm pores). The mixture is then placed into the solutions of the above-mentioned examples and comparative examples to form a compound. After the reaction forms a composite material, the aluminum-plastic bag is sealed and cut to obtain a heat-absorbing component. Polyethylene terephthalate film is folded into a bag shape using a machine. The bag is filled with plastic mesh as a carrier skeleton (0.1 mm thick, with 2 mm pores). The mixture is then placed into the solution of the above-mentioned example 5 to form a compound. After the reaction forms a composite material, the polyethylene terephthalate film is sealed and cut to obtain a heat-absorbing component.

[0123] The heat absorbers corresponding to Examples 1, 5, Comparative Example 1, and Comparative Example 2 were subjected to moisture content aging tests. Under conditions of 25°C and no restraint, these heat absorbers were placed for different times, and the mass and moisture content of the composite material were measured. Under conditions of 25°C and 0.4 MPa, these heat absorbers were placed for different times, and the mass and moisture content of the heat absorbers and composite material were measured again, thus simulating the effect of cell expansion on the heat absorbers and composite material. The results are shown in Tables 1 to 4. The initial moisture content of the composite material was tested using thermogravimetric analysis, and the weight loss rate of the composite material was measured using a balance to determine its moisture content.

[0124] Table 1. Aging test results of the heat absorber corresponding to Example 1.

[0125] Table 2 shows the aging test results of the heat absorber corresponding to Example 5, based on its moisture content.

[0126] Table 3 shows the aging test results of the heat absorber corresponding to Comparative Example 1, based on its moisture content.

[0127] Table 4 shows the aging test results of the heat absorber corresponding to Comparative Example 2, based on its moisture content.

[0128] It can be seen that the moisture content aging test results of Example 1, Comparative Example 1, and Comparative Example 2 are not significantly different, indicating that the inorganic additives added to the composite material provided in this application do not have an adverse effect on its moisture content aging test. Compared with Example 5, the composite material of Example 1 uses aluminum-plastic film as the encapsulation material, which results in better moisture content aging test results and is more conducive to the use of heat-absorbing components.

[0129] The heat-absorbing components corresponding to the embodiments and comparative examples were respectively placed on the large surface of the battery cells. Five battery cells were grouped together, and the same type of heat-absorbing component was placed between each battery cell to form a test module. A needle penetration test was performed on one of the battery cells to detect whether thermal diffusion occurred in other battery cells. The needle penetration test included a state of charge (SOC) of 100% for the battery cells and an initial temperature of 45°C for all battery cells. A 5mm straight steel needle was used to penetrate one of the battery cells at a speed of 1mm / s until it went out of control (smoke) and then the needle was stopped. After 2 minutes, the needle was pulled out. The maximum depth was 80mm. The temperature of other battery cells in the test module was continuously observed, and whether thermal diffusion occurred between adjacent battery cells was recorded during the process (if the temperature of adjacent battery cells exceeded 200°C and the duration exceeded 6 minutes, it was recorded as thermal diffusion). The results are shown in Table 5.

[0130] Table 5 Results of acupuncture experiments

[0131] Compared to Comparative Example 1, the composite material provided in this application contains inorganic additives. The phase change material and inorganic additives work synergistically to effectively prevent heat transfer between battery cells and prevent heat diffusion. Compared to Comparative Examples 2 and 3, the composite material provided in this application contains hydrophilic silica aerogel, which has low thermal conductivity and can effectively prevent heat transfer, while Comparative Examples 2 and 3 have no significant effect on hindering heat diffusion. Compared to Examples 8-9, 14-15, and 17-18, the temperature of adjacent battery cells in the needle penetration tests of the other examples did not reach 200°C, indicating that the composite material and heat-absorbing components have better heat absorption and insulation effects. Therefore, the composite material provided in this application has excellent heat absorption and insulation properties, which is beneficial for its use in battery modules and improves the safety of battery module use.

[0132] The above description represents the preferred embodiments of this application, but should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A composite material, characterized in that, It includes a polymer backbone, inorganic additives, and a phase change component, wherein the inorganic additives include at least one of hydrophilic aerogel and kaolin.

2. The composite material as described in claim 1, characterized in that, The hydrophilic aerogel includes at least one of hydrophilic silica aerogel, hydrophilic alumina aerogel, hydrophilic carbon aerogel, and hydrophilic nitride aerogel.

3. The composite material as described in claim 1 or 2, characterized in that, The hydrophilic aerogel has a pore size of 1 nm-500 nm and a porosity of 80%-99.8%.

4. The composite material according to any one of claims 1-3, characterized in that, The hydrophilic aerogel has a particle size Dv50 of 0.5 μm-20 μm.

5. The composite material according to any one of claims 1-4, characterized in that, The content of the inorganic additive in the composite material is 0.1wt%-10wt%.

6. The composite material according to any one of claims 1-5, characterized in that, The polymer skeleton has a pore size of 1μm-700μm and a porosity of 60%-90%.

7. The composite material according to any one of claims 1-6, characterized in that, The polymer backbone is made of at least one of polyacrylamide, sodium polyacrylate, polyacrylic acid, polymethacrylic acid, polyethylene glycol, and polyvinyl alcohol.

8. The composite material according to any one of claims 1-7, characterized in that, The content of the polymer backbone in the composite material is 1wt%-15wt%.

9. The composite material according to any one of claims 1-8, characterized in that, The composite material also includes at least one of a tackifier, a bactericide, and an antifreeze agent; The thickener includes at least one of carboxymethyl cellulose, guar gum, and carbomer. The bactericide includes at least one of polyquaternium salt, gold nifedipine, and biguanide salt; The antifreeze agent includes at least one of an organic solvent and an inorganic salt, wherein the organic solvent includes at least one of ethylene glycol and glycerol, and the inorganic salt includes at least one of sodium chloride, calcium chloride, and zinc chloride.

10. The composite material as described in claim 9, characterized in that, The content of the tackifier in the composite material is 0.05wt%-20wt%; The content of the bactericide in the composite material is 0.01wt%-5wt%; The content of the antifreeze in the composite material is 1wt%-20wt%.

11. The composite material according to any one of claims 1-10, characterized in that, The content of the phase change component in the composite material is greater than or equal to 70 wt%.

12. The composite material according to any one of claims 1-11, characterized in that, The phase change component includes at least one of water, butanol, ethyl acetate, acetic acid, and propionic acid.

13. A heat-absorbing element, characterized in that, Includes the composite material described in any one of claims 1-12.

14. The heat-absorbing element as described in claim 13, characterized in that, The heat-absorbing element (100) further includes an encapsulation structure (10), the encapsulation structure having an accommodating space (11) inside, and the composite material (20) being disposed in the accommodating space (11); The material of the encapsulation structure (10) includes at least one of plastic and metal.

15. The heat-absorbing element as described in claim 13, characterized in that, The heat-absorbing element (100) also includes a carrier skeleton, which has a sheet-like structure and multiple pores filled with the composite material.

16. The heat-absorbing element as described in claim 15, characterized in that, The thickness of the carrier skeleton is 0.05mm-2mm, and the diameter of the holes is 0.5mm-20mm.

17. A battery assembly, characterized in that, The battery assembly (300) includes a battery cell (200) and a heat absorber (100) as described in any one of claims 13-16, the heat absorber (100) being disposed on the surface of the battery cell (200).

18. An electrical appliance, characterized in that, Includes the battery assembly (300) as described in claim 17.

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