Heat-absorbing material and preparation method therefor, heat-absorbing part, battery assembly and electric device

Abstract

Provided in the present application are a heat-absorbing material and a preparation method therefor, a heat-absorbing part, a battery assembly and an electric device. The heat-absorbing material comprises a carrier, an entrainer and a phase-change component, wherein the phase-change component and the entrainer form a negative azeotrope. The entrainer and the phase-change component in the heat-absorbing material of the present application form a negative azeotrope, such that the phase-change component undergoes phase change when the temperature is lower than the phase-change temperature of the phase-change component, thereby absorbing heat, realizing a heat-absorbing effect, improving the heat-absorbing response speed of the heat-absorbing material, and further improving the usage safety of the battery assembly.

Description

Heat-absorbing materials and their preparation methods, heat-absorbing components, battery modules and electrical equipment

[0001] This application claims priority to Chinese Patent Application No. 2024112192966, filed on August 30, 2024, entitled “Heat-absorbing material and preparation method, heat-absorbing element, battery assembly and electrical device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to heat-absorbing materials and their preparation methods, heat-absorbing components, battery modules, and electrical devices. 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, hydrogels can be applied to the battery surface to improve safety by utilizing the heat absorption from the phase change of water within the hydrogel; however, the safety of existing hydrogels when used for heat absorption needs further improvement. Summary of the Invention

[0004] In view of this, this application provides a heat-absorbing material and its preparation method, a heat-absorbing component, a battery assembly, and an electrical device.

[0005] In a first aspect, this application provides an endothermic material comprising a carrier, an azeotropic agent, and a phase change component, wherein the azeotropic agent is used to form a negative azeotrope with the phase change component, and the carrier is used to load the phase change component and the azeotropic agent.

[0006] Optionally, the mass ratio of the phase change component to the azeotropic agent is (3.5-19):1.

[0007] Optionally, the phase change component includes water, and the azeotropic agent includes at least one of alcohols, ethers, esters, ketones, aldehydes, halogenated hydrocarbons, and alkanes.

[0008] Optionally, the alcohols include at least one of methanol, ethanol, n-propanol, and n-pentanol.

[0009] Optionally, the ethers include at least one of ethylene glycol diglycidyl ether and diisobutyl ether.

[0010] Optionally, the esters include at least one of dimethyl carbonate, n-propyl formate, isobutyl formate, ethyl acetate, isopropyl acetate, isoamyl acetate, and benzyl formate.

[0011] Optionally, the ketones include methyl isobutyl ketone.

[0012] Optionally, the aldehydes include furfural.

[0013] Optionally, the halohydrocarbon includes dichloroethane.

[0014] Optionally, the alkane includes cyclohexane.

[0015] Optionally, the azeotropic agent includes alcohols and esters.

[0016] Optionally, the mass ratio of the alcohol to the ester is 1:(2-4).

[0017] Optionally, the carrier has a three-dimensional network structure, the three-dimensional network structure having a porous structure, and the phase change component and the azeotropic agent are loaded in the porous structure.

[0018] Optionally, the content of the carrier in the heat-absorbing material is 5wt%-15wt%.

[0019] Optionally, the carrier material includes at least one of gelatin, sodium alginate, polyvinyl alcohol, polylactic acid, agar, chitosan, sodium polyacrylate, polyacrylamide, collagen, and silicone.

[0020] Optionally, the heat-absorbing material further includes an additive, the content of which is 0.5wt%-2wt%.

[0021] Optionally, the adjuvant includes at least one of humectants, antifreeze agents, fortifying agents, antioxidants, and bactericides.

[0022] Optionally, the heat-absorbing material is a hydrogel.

[0023] Secondly, this application provides a method for preparing a heat-absorbing material, comprising mixing a carrier precursor, an azeotropic agent and a phase change component, and reacting them to form the heat-absorbing material described in the first aspect.

[0024] Optionally, the preparation method further includes mixing a crosslinking agent with a carrier precursor, an azeotropic agent and a phase change component, and then crosslinking the mixture to form the heat-absorbing material.

[0025] Optionally, the carrier precursor includes a monomer and an initiator.

[0026] Optionally, the monomer includes at least one of sodium acrylate and acrylamide.

[0027] Optionally, the initiator includes at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, polyvinylpyrrolidone, phenyl ethyl ketone, tetramethyl dihydrogen ketone, and triphenylamine tribromorhodium salt.

[0028] Optionally, the reaction temperature is 50℃-80℃, and the reaction time is 3min-8min.

[0029] Thirdly, this application provides a heat-absorbing element, including the heat-absorbing material described in the first aspect or the heat-absorbing material prepared by the preparation method described in the second aspect.

[0030] Optionally, the heat-absorbing element further includes an encapsulation structure, the encapsulation structure having an internal accommodating space, and the heat-absorbing material disposed in the accommodating space.

[0031] Optionally, the heat-absorbing element further includes a frame having a plurality of holes filled with the heat-absorbing material.

[0032] Fourthly, this application provides a battery assembly, the battery assembly including a battery cell and the heat-absorbing element described in the third aspect, the heat-absorbing element being disposed on the surface of the battery cell.

[0033] Fifthly, this application provides an electrical device including the battery assembly described in the fourth aspect.

[0034] The azeotropic agent and phase change component in the heat-absorbing material of this application form a negative azeotrope, which causes the azeotropic agent and phase change component to undergo phase change below their own phase change temperature, thereby reducing the response temperature of the heat-absorbing material and improving the heat absorption response speed of the heat-absorbing material. When used to absorb heat from the battery cell, it further improves the safety of the battery cell and battery assembly. Moreover, the preparation method of this heat-absorbing material is simple and easy to operate, which is conducive to the application of the heat-absorbing material. Attached Figure Description

[0035] 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.

[0036] Figure 1 is a cross-sectional schematic diagram of a battery assembly provided in one embodiment of this application;

[0037] Figure 2 is a cross-sectional schematic diagram of a battery assembly provided in another embodiment of this application;

[0038] Figure 3 shows the DSC curve of the heat-absorbing material prepared in Example 8;

[0039] Figure 4 is a schematic cross-sectional view of the module in an embodiment of this application.

[0040] Figure 5 is a schematic diagram of the needle puncture position in a module experiment provided by an embodiment of this application;

[0041] Figure 6 is a schematic diagram of the temperature changes at different temperature measuring points in the needle penetration experiment corresponding to the heat-absorbing element provided in Example 6. Detailed Implementation

[0042] 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.

[0043] This application provides an endothermic material, comprising a carrier, an azeotropic agent, and a phase change component. The azeotropic agent is used to form a negative azeotrope with the phase change component. An azeotrope, also known as an azeotrope, refers to a liquid mixture of multiple components that has only one boiling point when boiling at constant pressure. When an azeotrope reaches its azeotropic point, the proportions of the various components in the gas produced by boiling are the same as the proportions of the various components in the liquid. When the vapor phase line (the boundary between the gas-liquid mixture and the gas phase) and the liquid phase line (the boundary between the liquid phase and the gas-liquid mixture) in the temperature-composition phase diagram of the azeotrope share a common minimum point, the azeotrope is a negative azeotrope. The azeotropic point of a negative azeotrope is lower than the boiling point of any one of its components. The heat-absorbing material of this application forms a negative azeotrope with the azeotropic agent and the phase change component, which causes the azeotropic agent and the phase change component to undergo a phase change below their own phase change temperature, thereby absorbing heat and achieving a heat absorption effect. Since the phase change temperature of the phase change component in the heat-absorbing material is reduced, the heat-absorbing material can generate heat absorption at a lower temperature, which improves the heat absorption response speed of the heat-absorbing material and further improves the safety of the use of the cell and battery assembly.

[0044] In heat-absorbing materials, the phase change component absorbs heat during the phase change process, giving the material heat-absorbing properties and thus blocking heat transfer. In one embodiment of this application, the phase change component is water. Heat-absorbing materials mainly rely on the phase change of the phase change component for heat absorption. Water has a large latent heat of vaporization, enabling it to absorb a large amount of heat during the phase change process, resulting in excellent heat-absorbing properties and a superior effect in blocking heat transfer. In another embodiment of this application, the heat-absorbing material is a hydrogel. Hydrogels can hold and retain a large amount of water and have good flexibility, which is beneficial for the use of heat-absorbing materials.

[0045] In one embodiment of this application, the content of the phase change component in the heat-absorbing material is greater than or equal to 55 wt%, which is beneficial to improving the heat absorption performance of the heat-absorbing material. Specifically, the content of the phase change component in the heat-absorbing material can be, but is not limited to, 60 wt% or more, 65 wt% or more, 70 wt% or more, 75 wt% or more, 80 wt% or more, 85 wt% or more, or 90 wt% or more. In one embodiment of this application, the content of the phase change component in the heat-absorbing material is 60 wt%-90 wt%, which ensures both the heat absorption performance of the heat-absorbing material and the content of other components, thereby improving the heat absorption response of the heat-absorbing material and making it more suitable for use.

[0046] When the heat-absorbing material does not contain an azeotropic agent, the phase change component undergoes a phase change at the first temperature, resulting in a heat-absorbing effect. In this application, the azeotropic agent in the heat-absorbing material forms a negative azeotrope with the phase change component, and the phase change component can undergo a phase change at the second temperature, which is lower than the first temperature. That is, the heat-absorbing material can cause the phase change component to undergo a phase change with less heat absorption, and the phase change component undergoes a phase change at a lower temperature, thereby enabling the heat-absorbing material to achieve the effects of heat absorption and insulation, greatly improving the heat absorption response speed, and fully utilizing the heat absorption capacity of the heat-absorbing material.

[0047] In one embodiment of this application, the absolute value of the boiling point difference between the phase change component and the azeotropic agent is less than 30°C, which is more conducive to the formation of a negative azeotrope between the phase change component and the azeotropic agent. Specifically, the absolute value of the boiling point difference between the phase change component and the azeotropic agent is less than 5°C, less than 10°C, less than 15°C, less than 20°C, or less than 25°C, etc.

[0048] In one embodiment of this application, the azeotropic agent includes at least one selected from alcohols, ethers, esters, ketones, aldehydes, halogenated hydrocarbons, and alkanes. Specifically, alcohols include at least one selected from methanol, ethanol, n-propanol, and n-pentanol; ethers include at least one selected from ethylene glycol diglycidyl ether and diisobutyl ether; esters include at least one selected from dimethyl carbonate, n-propyl formate, isobutyl formate, ethyl acetate, isopropyl acetate, isoamyl acetate, and benzyl formate; ketones include methyl isobutyl ketone, etc.; aldehydes include furfural, etc.; halogenated hydrocarbons include dichloroethane, etc.; and alkanes include cyclohexane, etc. The above-mentioned azeotropic agents more readily form negative azeotropes with water, which is beneficial for the preparation and use of endothermic materials.

[0049] In one embodiment of this application, the azeotropic agent includes alcohols and esters, with a mass ratio of alcohol to ester of 1:(2-4). This is beneficial for further reducing the phase change temperature of the phase change component in the heat-absorbing material and further improving the heat absorption response rate of the heat-absorbing material. Specifically, the mass ratio of alcohol to ester can be, but is not limited to, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.1, 1:3.3, 1:3.5, 1:3.7, 1:3.8, or 1:4, etc.

[0050] In one embodiment of this application, the mass ratio of the phase change component to the azeotropic agent is (3.5-19):1, which is beneficial for further reducing the phase change temperature of the phase change component in the heat-absorbing material, improving the heat absorption response rate of the heat-absorbing material, and ensuring the content of the phase change component in the heat-absorbing material, thus ensuring the heat absorption performance of the heat-absorbing material. Specifically, the mass ratio of the phase change component to the azeotropic agent can be, but is not limited to, 3.5:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, or 19:1, etc.

[0051] In one embodiment of this application, the content of the azeotropic agent in the heat-absorbing material is 0.5wt%-30wt%, which is beneficial for forming an azeotropic agent with the phase change component while ensuring the content of the phase change component in the heat-absorbing material, thereby further improving the performance of the heat-absorbing material. Specifically, the content of the azeotropic agent in the heat-absorbing material can be, but is not limited to, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 8wt%, 10wt%, 13wt%, 15wt%, 17wt%, 20wt%, 23wt%, 25wt%, 27wt%, 28.5wt%, or 30wt%. In one embodiment of this application, the content of the azeotropic agent in the heat-absorbing material can be 4wt%-30wt%. In another embodiment of this application, the content of the azeotropic agent in the heat-absorbing material can be 9wt%-27wt%.

[0052] In heat-absorbing materials, the carrier is used to support the phase change component and azeotropic agent, ensuring the content of the phase change component and thus guaranteeing the heat absorption performance of the material. Specifically, the phase change component is loaded onto the carrier before undergoing a phase change. After being heated and undergoing a phase change, the phase change component detaches from the carrier, absorbing heat in the process. Upon cooling, the phase change component is reloaded onto the carrier, thus achieving continuous and stable heat absorption. For example, when the phase change component is water, the carrier can support liquid water. When the liquid water absorbs heat and changes to a gaseous state, it can detach from the carrier. When the gaseous water cools and becomes liquid again, it can be reloaded onto the carrier, ensuring the continuous heat absorption performance and cooling effect of the heat-absorbing material.

[0053] In one embodiment of this application, the carrier has a three-dimensional network structure with porous structure, in which the phase change component and azeotropic agent are dispersed and loaded. The three-dimensional network structure of the carrier is beneficial for loading and encapsulating a large amount of phase change component, thereby improving the heat absorption performance of the heat-absorbing material.

[0054] In one embodiment of this application, the carrier material includes at least one selected from polysaccharides, proteins, and polymers. These carriers are more likely to load phase change components and azeotropic agents, and their good flexibility is beneficial for improving the compressive strength of the heat-absorbing material, thus facilitating its use in battery components. In another embodiment of this application, the carrier material includes at least one selected from gelatin, sodium alginate, polyvinyl alcohol, polylactic acid, agar, chitosan, sodium polyacrylate, polyacrylamide, collagen, and silicone. These carriers are readily available, which is beneficial for the preparation and use of heat-absorbing materials.

[0055] In one embodiment of this application, the carrier content in the heat-absorbing material is 5wt%-15wt%, which is beneficial for the loading of phase change components and azeotropic agents, as well as for ensuring the flexibility and strength of the heat-absorbing material, thereby improving its performance. Specifically, the carrier content in the heat-absorbing material can be, but is not limited to, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt%. In one embodiment of this application, the carrier content in the heat-absorbing material can be 6wt%-8wt%.

[0056] In one embodiment of this application, the heat-absorbing material further includes additives. Adding additives further improves and enhances the performance of the heat-absorbing material. In one embodiment of this application, the content of the additives in the heat-absorbing material is 0.5wt%-2wt%. Specifically, the content of the additives in the heat-absorbing material may be, but is not limited to, 0.5wt%, 0.7wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.7wt%, 1.9wt%, or 2wt%. In one embodiment of this application, the additives include at least one of humectants, antifreeze agents, fortifying agents, antioxidants, and bactericides. Humidifiers can improve the loading effect of the carrier on the phase change component and azeotropic agent, which is beneficial to increasing the content of the phase change component in the heat-absorbing material, thereby improving the heat absorption performance of the heat-absorbing material. When the phase change component of the heat-absorbing material in this application is water, the water will turn into ice at low temperatures, especially below zero, leading to an increase in the volume of both the water and the heat-absorbing material. The addition of antifreeze increases the intermolecular spacing of water, making it difficult for ice crystals to form and inhibiting the further expansion of ice crystals. This suppresses and slows down ice formation, thereby improving the antifreeze effect of the heat-absorbing material. This prevents the material from being compressed due to volume expansion when used at low temperatures, thus improving its safety. Reinforcing agents can improve the strength of the heat-absorbing material, which is beneficial for extending its service life. For example, it can allow the heat-absorbing material to be directly bonded to the surface of the battery cell, preventing thermal runaway. Antioxidants can improve the antioxidant properties of the heat-absorbing material, which is beneficial for extending its service life. Bactericides improve the antibacterial effect of the heat-absorbing material, which is beneficial for broadening its application scenarios. Specifically, the moisturizers include at least one of glycerol, ethylene glycol, sorbitol, trehalose, and lithium chloride; the antifreeze agents include at least one of glycerol and ethylene glycol; the fortifying agents include at least one of titanium dioxide, zinc oxide, calcium chloride, aluminum sulfate, guar gum, and carboxymethyl cellulose; the antioxidants include gallic acid, etc.; and the bactericides include imazalil, etc.

[0057] This application provides a method for preparing a heat-absorbing material, comprising mixing a carrier precursor, an azeotropic agent, and a phase change component to form the heat-absorbing material in any of the above embodiments. This preparation method is simple to operate, has low preparation cost, and is beneficial for the large-scale production and use of heat-absorbing materials.

[0058] In one embodiment of this application, the preparation method further includes mixing a crosslinking agent with a carrier precursor, an azeotropic agent, and a phase change component, and then crosslinking the mixture to form an endothermic material. The order in which the components are added is not particularly limited. For example, the carrier precursor, azeotropic agent, phase change component, and crosslinking agent can be mixed together and crosslinked to obtain the endothermic material; or, the azeotropic agent and phase change component can be mixed, then mixed with the carrier precursor and crosslinking agent, and crosslinked to obtain the endothermic material.

[0059] In one embodiment of this application, the carrier precursor includes a monomer and an initiator. The monomer, under the action of a crosslinking agent and an initiator, forms a carrier in the endothermic material, used to load phase change components, azeotropic agents, etc. In one embodiment of this application, the monomer includes at least one of sodium acrylate and acrylamide. After the reaction, at least one carrier of polyacrylamide and sodium polyacrylate can be formed. It is understood that before the reaction, the carrier precursor, azeotropic agent, phase change component, and crosslinking agent are mixed to form a mixture. In one embodiment of this application, the monomer content in the mixture is 4wt%-13wt%. Specifically, the monomer content in the mixture can be, but is not limited to, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, or 13wt%. The initiator can be classified according to the initiation type as thermal initiation, photoinitiation, photothermal initiation, etc., and can be selected as needed. In one embodiment of this application, the initiator includes at least one selected from hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, polyvinylpyrrolidone, phenyl ethyl ketone, tetramethyl dimethyl catalytic ketone, and triphenylamine tribromorhodium. In one embodiment of this application, the content of the initiator in the mixture is 0.01 wt%-0.8 wt%. Specifically, the content of the initiator in the mixture may be, but is not limited to, 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.6 wt%, or 0.8 wt%. In one embodiment, the content of the initiator in the mixture may be 0.01 wt%-0.2 wt%.

[0060] In one embodiment of this application, the carrier precursor includes at least one selected from gelatin, sodium alginate, polyvinyl alcohol, polylactic acid, agar, chitosan, sodium polyacrylate, polyacrylamide, collagen, and silicone. The carrier precursor is further cross-linked by a cross-linking agent, increasing its chain length and molecular weight to form a carrier in the heat-absorbing material. It is understood that the difference between these carrier precursors and the carrier in the heat-absorbing material is that the molecular weight of the carrier precursor is smaller than that of the carrier. In one embodiment of this application, the content of the carrier precursor in the mixture is 4 wt%-13 wt%. Specifically, the content of the carrier precursor in the mixture can be, but is not limited to, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, or 13 wt%.

[0061] In this application, the crosslinking agent can crosslink the carrier precursor, which is beneficial for the formation of a three-dimensional network structure, thereby forming a carrier capable of loading phase change components and azeotropic agents. Simultaneously, the crosslinking agent helps to increase the crosslinking density of the carrier, thereby improving the strength of the formed carrier and enhancing the usability of the heat-absorbing material. In one embodiment of this application, the crosslinking agent includes at least one of silica, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, nanoclay, methylcellulose, dimethacrylamide, N,N'-methylenebisacrylamide, trimethylolpropane, polyoxypropylene ether triol, benzoyl peroxide, dicumyl peroxide, and 1,1-di-tert-butylcyclohexane peroxide. In one embodiment of this application, the content of the crosslinking agent in the mixture is 0.1 wt%-4 wt%, ensuring both crosslinking efficiency and the performance of the formed carrier, which is beneficial for the usability of the heat-absorbing material. Specifically, the content of the crosslinking agent in the mixture can be, but is not limited to, 0.1 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.7 wt%, 2 wt%, 2.3 wt%, 2.5 wt%, 2.8 wt%, 3 wt%, 3.3 wt%, 3.5 wt%, 3.8 wt%, or 4 wt%. In one embodiment of this application, the content of the crosslinking agent in the mixture can be 0.2 wt% to 0.6 wt%.

[0062] In one embodiment of this application, the mixture further includes a crosslinking promoter. The crosslinking promoter can accelerate the reaction and improve preparation efficiency. In one embodiment of this application, the crosslinking promoter includes at least one selected from divinylbenzene, diisocyanate, and tetramethylethylenediamine. In one embodiment of this application, the content of the crosslinking promoter in the mixture is 0.01 wt%-0.5 wt%. Specifically, the content of the crosslinking promoter in the mixture can be, but is not limited to, 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, or 0.5 wt%. In one embodiment, the content of the crosslinking promoter in the mixture can be 0.01 wt%-0.3 wt%.

[0063] In one embodiment of this application, the content of the azeotropic agent in the mixture can be 0.5wt%-30wt%. Specifically, the content of the azeotropic agent in the mixture can be, but is not limited to, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 8wt%, 10wt%, 13wt%, 15wt%, 17wt%, 20wt%, 23wt%, 25wt%, 27wt%, 28.5wt%, or 30wt%, etc.

[0064] In one embodiment of this application, the content of the phase change component in the mixture can be 60wt%-90wt%. Specifically, the content of the phase change component in the mixture can be, but is not limited to, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, or 90wt%.

[0065] In one embodiment of this application, the phase change component and azeotropic agent can be mixed, and then a carrier precursor and a crosslinking agent can be added, followed by a reaction to obtain an endothermic material. In another embodiment of this application, the phase change component and azeotropic agent can be mixed, and then a carrier precursor can be added. After mixing evenly, a crosslinking agent, an initiator, an auxiliary agent, and a crosslinking promoter can be added. After stirring evenly (e.g., stirring for 3-8 minutes), an endothermic material can be obtained by a reaction.

[0066] In one embodiment of this application, the reaction temperature is 50℃-80℃, and the reaction time is 3min-8min, which is beneficial for cross-linking polymerization and the formation of a heat-absorbing material with excellent performance. Specifically, the reaction temperature can be, but is not limited to, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, or 80℃, and the reaction time can be, but is not limited to, 3min, 4min, 5min, 6min, 7min, or 8min. In this application, the heat-absorbing material is formed by reaction curing, and the curing method can be, but is not limited to, thermosetting, photosetting, photothermal dual curing, moisture curing, chemical curing, etc.

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

[0068] In one embodiment of this application, the heat-absorbing element is made of a heat-absorbing material. That is, the heat-absorbing material constitutes the heat-absorbing element. This material possesses good strength and flexibility, allowing it to be directly applied to the surface of the battery cell, promptly absorbing the heat generated by the cell, improving response speed and heat absorption efficiency, and thus enhancing the safety of the battery cell. In another embodiment of this application, the heat-absorbing element includes an encapsulation structure and a heat-absorbing material. The encapsulation structure has an internal accommodating space, and the heat-absorbing material is disposed within this space. By encapsulating the heat-absorbing material within the encapsulation structure, direct contact between the heat-absorbing material and the battery cell is further avoided, thus preventing short circuits and other problems, improving the safety and lifespan of the heat-absorbing element. Furthermore, the encapsulation structure can fix and confine the heat-absorbing material, further improving the mechanical properties of the heat-absorbing element.

[0069] In one embodiment of this application, the ratio of the volume of the heat-absorbing material to the volume of the accommodating space is 50%-70%. This ensures the content of the heat-absorbing 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 during the heat absorption process, 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 heat-absorbing 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 encapsulation structure in the heat-absorbing component serves to seal and house the heat-absorbing structure. In one embodiment of this application, the encapsulation structure is made of at least one of 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-absorbing component. 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-absorbing component can match the battery cell, thereby improving the heat absorption efficiency of the heat-absorbing component. In one embodiment of this application, a mixture forming the heat-absorbing material can be placed inside the encapsulation film, reacting to form the heat-absorbing material. After sealing the encapsulation film, an encapsulation structure is formed, resulting in the heat-absorbing component.

[0071] In one embodiment of this application, the heat-absorbing component further includes a skeleton with multiple holes filled with heat-absorbing material. The skeleton serves to support, fix, and restrict the heat-absorbing material, improving the mechanical properties of the heat-absorbing component. The skeleton has multiple holes filled with heat-absorbing 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 skeleton along its thickness direction. That is, the holes are through holes, which facilitates the filling and dispersion of the heat-absorbing material. In another embodiment of this application, the holes do not penetrate the skeleton along its thickness direction. That is, the holes are blind holes, which facilitates the loading of the heat-absorbing material. In this application, the holes in the 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 skeleton along its thickness direction. In another embodiment of this application, the holes uniformly penetrate the skeleton along its thickness direction. That is, along the thickness direction of the skeleton, the holes have the same diameter on a cross-section perpendicular to the thickness direction, which facilitates the uniform filling of the heat-absorbing material within the skeleton and improves the overall support performance of the skeleton. In one embodiment of this application, the skeleton material can be, but is not limited to, at least one of polyester, polypropylene, and glass fiber. Skeletons made from the above materials have superior support and mechanical properties. In one embodiment of this application, the skeleton can be placed inside an encapsulation film, and then a mixture forming the heat-absorbing material can be added. After reaction, the heat-absorbing material is formed, and the encapsulation film is sealed to form an encapsulation structure, thus obtaining a heat-absorbing component.

[0072] 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 heat-absorbing 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. Simultaneously, the phase change temperature of the phase change component in the heat-absorbing material is lower, enabling it to absorb heat even when the battery cell generates relatively little heat, thereby blocking heat transfer. 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.

[0073] 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 1, 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 2, 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. For example, when one of the multiple battery cells experiences thermal runaway, the heat absorber adjacent to it can absorb the heat from the cell, preventing rapid heat transfer. At the same time, when the heat absorber adjacent to the cell that has not experienced thermal runaway is subjected to lower heat, the phase change component in the heat absorber material can undergo a phase change. Thus, the heat absorber material can exert its heat absorption effect before thermal runaway propagation occurs, fully utilizing the heat absorption capacity of the heat absorbers in the battery module, improving the heat absorption response speed, reducing the risk of thermal runaway propagation, and improving the safety of the battery module.

[0074] 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.

[0075] The effects of the technical solution in this application will be further illustrated below with specific examples.

[0076] Example 1

[0077] After mixing the azeotropic agent and water, acrylamide was added and stirred until homogeneous. Then, ammonium persulfate, N,N'-methylenebisacrylamide, and glycerol were added and stirred until homogeneous. Finally, N,N,N,N-tetramethylethylenediamine was added and stirred for 8 minutes to form a mixture. The contents of the mixture were: ammonium persulfate 0.3 wt%, N,N'-methylenebisacrylamide 0.07 wt%, and N,N,N,N-tetramethylethylenediamine 0.03 wt%. The mixture was then heated in a 60°C water bath for 8 minutes to obtain the heat-absorbing material.

[0078] The heat-absorbing material includes 10 wt% ethanol (azeotropic agent), 80 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0079] Example 2

[0080] The difference from Example 1 is that the heat-absorbing material includes 20 wt% ethanol (azeotropic agent), 70 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0081] Example 3

[0082] The difference from Example 1 is that the heat-absorbing material includes 5 wt% ethanol (azeotropic agent), 5 wt% dimethyl carbonate (azeotropic agent), 80 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0083] Example 4

[0084] The difference from Example 1 is that the heat-absorbing material includes 10 wt% of an azeotropic agent (the azeotropic agent is ethanol and dimethyl carbonate in a mass ratio of 1:2), 80 wt% of water, 0.6 wt% of glycerol, and 9.4 wt% of polyacrylamide.

[0085] Example 5

[0086] The difference from Example 1 is that the heat-absorbing material includes 2.5 wt% ethanol (azeotropic agent), 7.5 wt% dimethyl carbonate (azeotropic agent), 80 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0087] Example 6

[0088] The difference from Example 1 is that the heat-absorbing material includes 2 wt% ethanol (azeotropic agent), 8 wt% dimethyl carbonate (azeotropic agent), 80 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0089] Example 7

[0090] The difference from Example 1 is that the heat-absorbing material includes 1.5 wt% ethanol (azeotropic agent), 8.5 wt% dimethyl carbonate (azeotropic agent), 80 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0091] Example 8

[0092] The difference from Example 1 is that the heat-absorbing material includes 10 wt% ethanol (azeotropic agent), 10 wt% dimethyl carbonate (azeotropic agent), 70 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0093] Example 9

[0094] The difference from Example 1 is that the heat-absorbing material includes 9 wt% of an azeotropic agent (the azeotropic agent is ethanol and dimethyl carbonate in a mass ratio of 1:3), 81 wt% of water, 0.6 wt% of glycerol, and 9.4 wt% of polyacrylamide.

[0095] Example 10

[0096] The difference from Example 1 is that the heat-absorbing material includes 5 wt% of an azeotropic agent (the azeotropic agent is ethanol and dimethyl carbonate in a mass ratio of 1:3), 85 wt% of water, 0.6 wt% of glycerol, and 9.4 wt% of polyacrylamide.

[0097] Example 11

[0098] The difference from Example 1 is that the heat-absorbing material includes 15 wt% of an azeotropic agent (the azeotropic agent is ethanol and dimethyl carbonate in a mass ratio of 1:3), 75 wt% of water, 0.6 wt% of glycerol, and 9.4 wt% of polyacrylamide.

[0099] Example 12

[0100] The difference from Example 1 is that the heat-absorbing material includes 12 wt% of an azeotropic agent (the azeotropic agent is ethanol and dimethyl carbonate in a mass ratio of 1:3), 78 wt% of water, 0.6 wt% of glycerol, and 9.4 wt% of polyacrylamide.

[0101] Example 13

[0102] The difference from Example 1 is that the heat-absorbing material includes 20 wt% n-butyraldehyde (azeotropic agent), 80 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0103] Comparative Example 1

[0104] The difference from Example 1 is that the heat-absorbing material comprises 90 wt% water, 0.6 wt% glycerol and 9.4 wt% polyacrylamide.

[0105] Performance testing

[0106] (1) Differential scanning calorimetry (DSC) was used to analyze the endothermic materials (sample mass controlled between 2 mg and 2.5 mg) prepared in the above examples and comparative examples. The results are shown in Table 1. The analysis was conducted under an inert gas atmosphere (N2, flow rate of 50 ml / min), with a test range of 25℃-150℃ and a heating rate of 10℃ / min. DSC curves were obtained. The normalized peak area (i.e., endothermic capacity) was obtained by integrating the DSC curves, and the temperature corresponding to the peak value in the DSC curve is the phase transition temperature. Figure 3 shows the DSC curve of the endothermic material prepared in Example 8. The sample mass was 2.2 mg, and the normalized peak area (including the area from 40℃ to the baseline) was obtained by integrating its DSC curve. The endothermic capacity was 1477.52 J·g. -1 The peak temperature corresponds to 80.68℃.

[0107] (2) The thermal runaway prevention capability of heat-absorbing materials was verified by using module experiments (needle penetration test).

[0108] The heat-absorbing materials of Examples 5, 6 and Comparative Example 1 were encapsulated in aluminum-plastic film to prepare heat-absorbing components with dimensions of 614mm (length) * 127mm (width) * 1.5mm (thickness).

[0109] For each embodiment / comparative example, five identical battery cells (as shown in Figure 4, which is a schematic cross-sectional view of the module experiment provided in this application embodiment, and Figure 5, which is a schematic diagram of the needle penetration position in the module experiment provided in this application embodiment; for easy differentiation, they are designated as cell #1, cell #2, cell #3, cell #4, and cell #5; each cell is a square cell with a SOC of 100%) are arranged sequentially along the thickness direction (the length of the square cell used is greater than its width, and the width is greater than its thickness) to form a module. A heat absorber 100 is arranged between each adjacent cell, and the thickness direction of the heat absorber 100 is the same as the thickness direction of the cell 200. Module clamps 400 are provided on both sides of the outermost cell 200. At a cell temperature of 45±2℃, a needle penetration test is performed on the middle cell among the five cells. The needle penetration test was conducted using a 5mm straight steel needle at a speed of 1mm / s. The needle penetration was stopped when the depth reached 10mm, and the needle was not removed. The needle penetration location was point A (positive side) of cell #3.

[0110] The temperature at different locations within the module was monitored, and the highest temperature at each location was recorded. Simultaneously, the temperatures at locations T1 and T3 were recorded. The time from the onset of thermal runaway at the needle-pierced cell (i.e., the temperature at T1 begins to rise significantly, specifically at 65s on the horizontal axis of Figure 6 corresponding to Example 6) to the onset of decreasing heating rate at T3 is the time when the adjacent heat-absorbing material of the needle-pierced cell begins to function. Figure 6 is a schematic diagram of temperature changes at different measurement points during the needle-piercing experiment corresponding to the heat-absorbing component provided in Example 6. The arrows in Figure 6 indicate the time points when the adjacent heat-absorbing material of the needle-pierced cell begins to function. For each example / comparative example, if any cell other than the needle-pierced cell experiences thermal runaway (rapid temperature rise, cell smoke), the needle-piercing experiment result is recorded as failing; if no other cell experiences thermal runaway, it is considered passing. The needle-piercing experiment results corresponding to Examples 5, 6, and Comparative Example 1 are shown in Table 2.

[0111] Table 1 DSC Detection Results

[0112] Table 2 Results of acupuncture experiment

[0113] As can be seen, compared with Comparative Example 1, the heat-absorbing material provided in this application contains an azeotropic agent, and the phase change temperature of the heat-absorbing material is reduced, indicating that the azeotropic agent forms a negative azeotrope with water, which is beneficial to improving the heat absorption response speed of the heat-absorbing material. Furthermore, the heat-absorbing material also has better heat absorption capacity, which is beneficial to its use. Compared with Examples 3 and 7, the heat-absorbing materials prepared in Examples 4-6 have both a lower phase change temperature and excellent heat absorption capacity, resulting in better overall performance and making them more suitable for use. According to Examples 1 and 2-12, a suitable mass ratio of phase change component to the azeotropic agent is beneficial to improving the heat absorption capacity of the heat-absorbing material and reducing its heat absorption temperature, which is beneficial to its application. According to Examples 1 and 13, a suitable azeotropic agent is beneficial to improving the heat absorption response speed of the heat-absorbing material, increasing its heat absorption capacity, and reducing hazards. According to Examples 5-6 and Comparative Example 1, the heat-absorbing material provided in this application contains an azeotropic agent, has a fast heat absorption response speed, and strong anti-thermal runaway capability, which is beneficial to extending the service life of the battery cell and the widespread application of the heat-absorbing material.

[0114] 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 heat-absorbing material, characterized in that, It includes a carrier, an azeotropic agent, and a phase change component, wherein the azeotropic agent is used to form a negative azeotrope with the phase change component, and the carrier is used to load the phase change component and the azeotropic agent.

2. The heat-absorbing material as described in claim 1, characterized in that, The mass ratio of the phase change component to the azeotropic agent is (3.5-19):

1.

3. The heat-absorbing material as described in claim 1 or 2, characterized in that, The phase change component includes water, and the azeotropic agent includes at least one of alcohols, ethers, esters, ketones, aldehydes, halogenated hydrocarbons, and alkanes.

4. The heat-absorbing material as described in claim 3, characterized in that, The heat-absorbing material satisfies at least one of the following (a) to (g): (a) The alcohols include at least one of methanol, ethanol, n-propanol and n-pentanol; (b) The ethers include at least one of ethylene glycol diglycidyl ether and diisobutyl ether; (c) The esters include at least one of dimethyl carbonate, n-propyl formate, isobutyl formate, ethyl acetate, isopropyl acetate, isoamyl acetate and benzyl formate; (d) The ketones include methyl isobutyl ketone; (e) The aldehydes include furfural; (f) The halohydrocarbons include dichloroethane; (g) The alkanes include cyclohexane.

5. The heat-absorbing material according to any one of claims 1-4, characterized in that, The azeotropic agents include alcohols and esters.

6. The heat-absorbing material according to any one of claims 3-5, characterized in that, The mass ratio of the alcohol to the ester is 1:(2-4).

7. The heat-absorbing material according to any one of claims 1-6, characterized in that, The carrier has a three-dimensional network structure, which forms a porous structure, and the phase change component and the azeotropic agent are loaded in the porous structure.

8. The heat-absorbing material according to any one of claims 1-7, characterized in that, The carrier content in the heat-absorbing material is 5wt%-15wt%.

9. The heat-absorbing material as described in claim 7 or 8, characterized in that, The carrier material includes at least one of gelatin, sodium alginate, polyvinyl alcohol, polylactic acid, agar, chitosan, sodium polyacrylate, polyacrylamide, collagen, and silicone.

10. The heat-absorbing material according to any one of claims 1-9, characterized in that, The heat-absorbing material also includes additives, and the content of the additives in the heat-absorbing material is 0.5wt%-2wt%. The additives include at least one of humectants, antifreeze agents, fortifying agents, antioxidants, and bactericides.

11. The heat-absorbing material according to any one of claims 1-10, characterized in that, The heat-absorbing material is a hydrogel.

12. A method for preparing a heat-absorbing material, characterized in that, This includes mixing a carrier precursor, an azeotropic agent, and a phase change component, and reacting them to form the heat-absorbing material according to any one of claims 1-11.

13. The method for preparing the heat-absorbing material as described in claim 12, characterized in that, The crosslinking agent is mixed with the carrier precursor, azeotropic agent and phase change component, and crosslinked to form the heat-absorbing material.

14. The method for preparing the heat-absorbing material as described in claim 12, characterized in that, The carrier precursor includes a monomer and an initiator; The monomer includes at least one of sodium acrylate and acrylamide; The initiator includes at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, polyvinylpyrrolidone, phenyl ethyl ketone, tetramethyl dihydrogen ketone, and triphenylamine tribromorhodium salt.

15. The method for preparing the heat-absorbing material according to any one of claims 12-14, characterized in that, The reaction temperature is 50℃-80℃, and the reaction time is 3min-8min.

16. A heat-absorbing element, characterized in that, The heat-absorbing material includes the heat-absorbing material according to any one of claims 1-11 or the heat-absorbing material prepared by any one of claims 12-15.

17. The heat-absorbing element as described in claim 16, characterized in that, The heat-absorbing component also includes an encapsulation structure, the encapsulation structure having an internal accommodating space, and the heat-absorbing material disposed within the accommodating space.

18. The heat-absorbing element as described in claim 16 or 17, characterized in that, The heat-absorbing component also includes a frame having multiple holes filled with the heat-absorbing material.

19. A battery assembly, characterized in that, The battery assembly includes a battery cell and a heat-absorbing element as described in any one of claims 16-18, the heat-absorbing element being disposed on the surface of the battery cell.

20. An electrical appliance, characterized in that, Includes the battery assembly as described in claim 19.

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