Current collector and preparation method thereof, electrode, battery and electric equipment

Abstract

The invention provides a current collector and a preparation method thereof, an electrode, a battery and electric equipment, the current collector comprises a polymer base film and a metal layer arranged on at least one side of the polymer base film, and the polymer base film comprises a phase change material. According to the current collector provided by the invention, the phase change material is added into the polymer base film, and the phase change material absorbs a large amount of heat through phase change, so that heat accumulation in the battery is reduced, heat diffusion in the battery is reduced, the temperature of the battery is reduced, and the safety performance of the battery is improved.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical technology, and in particular relates to a current collector and a preparation method thereof, an electrode, a battery and an electrical device. Background Art

[0002] As a core component of current new energy vehicles, the safety of lithium-ion power batteries has attracted widespread attention. The current collector, a key battery component, plays a decisive role in battery safety, but existing current collectors are insufficient to meet battery safety requirements. Summary of the Invention

[0003] In response to the problems existing in the prior art, the present application provides a current collector and a preparation method thereof, an electrode, a battery and an electrical device.

[0004] To address the aforementioned issues, the present application provides, in a first aspect, a current collector. According to embodiments of the present application, the current collector comprises a polymer-based film and a metal layer disposed on at least one side of the polymer-based film, wherein the polymer-based film comprises a phase-change material. The current collector provided herein incorporates a phase-change material into the polymer-based film. The phase-change material absorbs a large amount of heat through phase change, reducing heat accumulation within the battery, thereby reducing heat diffusion within the battery, lowering the battery temperature, and improving the battery's safety performance.

[0005] A second aspect of the present application provides a method for preparing the current collector described in the first aspect, comprising mixing the phase change material and the polymer, and drying to obtain the polymer-based film comprising the phase change material; and disposing a metal layer on at least one surface of the polymer-based film to obtain the current collector. The current collector preparation method provided herein is simple and amenable to large-scale production.

[0006] In a third aspect, the present application provides an electrode comprising the current collector described in the first aspect or the current collector prepared by the method for preparing the current collector described in the second aspect. The electrode provided in the present application has excellent safety performance due to the inclusion of the current collector.

[0007] A fourth aspect of the present application provides a battery comprising the electrode according to the third aspect. The battery provided in the present application has excellent safety performance.

[0008] In a fifth aspect, the present application provides an electrical device comprising the battery described in the fourth aspect. Because the electrical device utilizes the battery, it exhibits excellent safety performance. The features and advantages described above for the battery also apply to the electrical device and will not be further elaborated here.

[0009] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Among them:

[0011] Figure 1 is a schematic cross-sectional view of a current collector in some embodiments of the present application;

[0012] Figure 2 It is a schematic diagram of the thermal diffusion test method of this application.

[0013] Explanation of the reference numerals: 1: polymer base film; 2: metal layer; A: phase change material; H: heating plate; U1, U2: batteries. DETAILED DESCRIPTION

[0014] In order to make the technical problems, technical solutions and beneficial effects solved by this application more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0015] The cause of battery thermal runaway may be the multi-factor coupled mechanical, electrical and thermal abuse, and internal short circuit is a common feature of various thermal runaway inducements; after thermal runaway occurs, it will further expand within the battery system, causing thermal runaway of the entire battery pack. For the stage of thermal runaway expansion, the process can be controlled from the levels of materials, structural design, thermal management, and monitoring systems. Compared with traditional copper-aluminum foil, the composite current collector is lighter and the assembled battery has a higher energy density; in addition, the polymer base film in the composite current collector can be melted in time during the needle puncture internal short circuit of the battery, avoiding the continuous short circuit between the composite current collector and the steel needle to release heat and cause thermal runaway of the battery, but this type of composite current collector still has no way to prevent heat diffusion.

[0016] In view of this, please refer to Figure 1 The present application provides a current collector comprising a polymer base film 1 and a metal layer 2 disposed on at least one side of the polymer base film 1 , wherein the polymer base film 1 comprises a phase change material A.

[0017] Specifically, considering that the heat generated by short circuit in the battery in the prior art cannot be released, the present application adds phase change material to the polymer base film. The phase change material can absorb a large amount of heat during phase change, reducing the heat accumulation inside the battery, thereby reducing the diffusion of heat inside the battery, lowering the battery temperature, and improving the safety performance of the battery.

[0018] In the present application, phase change material is a type of material that can absorb or release a large amount of latent heat through changes in the state of matter within a specific temperature range. It has good temperature stability and can be recycled. In the present application, the polymer-based membrane includes a polymer, and the polymer provides a support structure for the polymer-based membrane. The polymer-based membrane has high tensile strength, flexibility and ductility, and the polymer material has excellent heat resistance and is more stable at high temperatures. When used in batteries, it is not easily corroded by the electrolyte. A metal layer is formed on the surface of at least one side of the polymer-based membrane to achieve rapid conduction of electrons during battery charging and discharging, ensuring stable bonding with the active material layer. The phase change material and the polymer have good compatibility, so that the diaphragm has a stable structure.

[0019] The current collector provided in the present application has the following effects: the current collector provided in the present application, by adding a phase change material to the polymer base film, the phase change material absorbs a large amount of heat through phase change, reduces the heat accumulation inside the battery, thereby reducing the heat diffusion inside the battery, lowering the battery temperature, and improving the safety performance of the battery.

[0020] In this application, the presence of phase change material in the current collector can be determined using differential scanning calorimetry (DSC) with reference to GB / T 43820-2024, as well as its heat storage and release properties. Furthermore, NMR can be used to verify the composition of the phase change material. Specifically, a unit current collector is soaked in n-hexane solution, the solution is dried, and then a deuterated reagent is added to dissolve the solution, followed by hydrogen NMR.

[0021] In some embodiments, the phase change material includes at least one of a polybasic aliphatic hydrocarbon, a fatty alcohol, a fatty acid, a polyol, a polyacid, and a polyester.

[0022] Specifically, the above-mentioned phase change material has good stability, wide sources, and low cost. When used in the current collector, it can effectively absorb or release heat, thereby reducing the heat accumulation inside the battery while maintaining the good performance of the current collector, thereby reducing the diffusion of heat inside the battery, lowering the battery temperature and the probability of thermal runaway, and improving the safety performance of the battery.

[0023] In some preferred embodiments, the phase change material includes at least one of n-tetracosane, aliphatic hydrocarbons having more than 24 carbon atoms, beeswax, 1-hexadecanol, monoalcohols having more than 16 carbon atoms, stearic acid, D-mannitol, erythritol, pentaerythritol, trimethylolethane, pyromellitic acid, trimethylolpropane tristearate, pentaerythritol tetrastearate, ethyl stearate and dipentaerythritol hexaoctanoate.

[0024] Specifically, the phase change material is selected from at least one of the above materials, which further reduces the internal heat of the battery while maintaining the performance of the current collector, thereby improving the safety performance of the battery.

[0025] In some embodiments, the polymer includes at least one of polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, poly(p-phenylene terephthalamide), polyimide, polycarbonate, polyetherketone, polyoxymethylene, polyphenylene sulfide, polyphenylene oxide, polyvinyl chloride, polyamide, and polytetrafluoroethylene; and / or the metal layer includes at least one of aluminum, copper, nickel, iron, titanium, silver, gold, cobalt, chromium, molybdenum, tungsten, and stainless steel.

[0026] Specifically, the polymer is lightweight and, when used in current collectors, can increase the battery's energy density. It also offers high-temperature resistance, excellent flexibility, and chemical stability, making it less susceptible to corrosion by electrolytes, thereby extending the battery's lifespan. The metal in the metal layer has excellent electrical conductivity, enabling rapid electron conduction during the battery's charge and discharge processes.

[0027] In some preferred embodiments, the polymer includes at least one of polypropylene, polyethylene terephthalate, and polyimide; and / or the metal layer includes aluminum and / or copper.

[0028] Specifically, the polymer and metal layers are selected from at least one of the above materials, which can improve the energy density and service life of the battery while maintaining the conductive properties of the current collector.

[0029] In some embodiments, the thickness of the polymer base film is 2 μm to 8 μm; and / or the thickness of the metal layer is 0.5 μm to 2.5 μm. Generally, the thickness of the metal layer is converted by calibrating the sheet resistance of the metal layer at 1 μm, and the thickness of the polymer base film is calculated by subtracting the thickness of the metal layer from the total thickness of the composite current collector. More accurately, the thickness of the polymer base film and the thickness of the metal layer are measured using an electron microscope.

[0030] Specifically, the thickness of the polymer base film can be, but is not limited to, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, or any combination thereof. Within this range, the polymer base film can provide sufficient mechanical strength to support the current collector, thereby increasing the battery's energy density; it can also shorten the electron transmission distance and reduce the internal resistance of the current collector, thereby reducing energy loss and heat generation during charging and discharging. The thickness of the metal layer can be, but is not limited to, 0.5 μm, 0.8 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.2 μm, 2.5 μm, or any combination thereof. Within this range, the metal layer can reduce costs, increase the battery's energy density, provide electrical conductivity to the current collector, and reduce its internal resistance.

[0031] In some embodiments, the number average molecular weight of the phase change material is less than or equal to 1000 g / mol; and / or the phase change temperature T m Meet: 50℃≤T m ≤200℃.

[0032] Specifically, the number average molecular weight of the phase change material in this application can be determined by mass spectrometry; the phase change temperature of the phase change material can be determined by the melting peak measured by DSC. The number average molecular weight of the phase change material is less than or equal to 1000 g / mol so that it can be better mixed with the polymer. The phase change temperature of the phase change material is T m The temperature may be, but is not limited to, 50°C, 80°C, 95°C, 100°C, 120°C, 150°C, 180°C, 195°C, 200°C or any two thereof. The phase change temperature of the phase change material is within the above range and can undergo phase change below the thermal runaway temperature of the current collector, thereby absorbing heat, reducing the battery temperature, and improving the safety performance of the battery.

[0033] In some embodiments, the phase change material accounts for 1% to 50% by weight of the polymer-based film.

[0034] Specifically, the mass percentage of the phase change material in the polymer base film can be but is not limited to 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% or a range composed of any two of them. The mass percentage of the phase change material in the polymer base film within the above range ensures the mechanical strength of the polymer base film and the energy density of the battery, and is beneficial to absorbing the heat generated during the battery cycle, reducing the battery temperature and improving the safety of the battery.

[0035] In the present application, the mass percentage of the phase change material in the polymer base film can be tested by the following method: disassembling the electrode to obtain the current collector, placing the current collector in a high-temperature vacuum environment, evaporating the phase change material, and obtaining a current collector without phase change material. The mass of the phase change material can be obtained by subtracting the mass of the current collector without phase change material after evaporation from the mass of the original current collector. The mass of the polymer is obtained by thermogravimetrically measuring the current collector without phase change material. The mass percentage of the phase change material in the polymer base film = the mass of the phase change material / (mass of the phase change material + the mass of the polymer) × 100%.

[0036] In some preferred embodiments, the phase change material accounts for 20%-50% by weight of the polymer-based film.

[0037] Specifically, when the mass percentage of the phase change material to the polymer base film is within the above range, the temperature inside the battery and the probability of thermal runaway can be further reduced while ensuring the battery energy density, thereby improving the safety performance of the battery.

[0038] In some embodiments, the phase change material is grafted onto the polymer and / or the phase change material is copolymerized with the polymer.

[0039] Specifically, the phase change material and the polymer are grafted or copolymerized. The phase change material can be grafted onto the main chain of the polymer, or the phase change material and the polymer monomer form a block copolymer. Through chemical bonding, the phase change material can be effectively prevented from flowing or leaking during the phase change process, thereby enhancing the structural stability of the polymer-based membrane, while improving the internal bonding force of the polymer-based membrane, enhancing the mechanical properties of the polymer-based membrane, further reducing the probability of thermal runaway of the battery, and improving the mechanical properties and safety performance of the battery.

[0040] In some embodiments, the phase change material exists in the form of a core-shell structure, wherein the core of the core-shell structure comprises the phase change material, and the shell of the core-shell structure comprises a cross-linked polymer and / or an inorganic material.

[0041] Specifically, the phase change material forms a core-shell structure with a cross-linked polymer and / or an inorganic material, and the cross-linked polymer and / or the inorganic material wraps the phase change material, which can also effectively prevent the flow or leakage of the phase change material during the phase change process, further increasing the mechanical properties of the current collector.

[0042] In some embodiments, the cross-linked polymer includes at least one of polymethyl methacrylate, polystyrene, urea-formaldehyde resin, polyurethane, and polyurea; and the inorganic material includes silicon dioxide and / or titanium dioxide.

[0043] Specifically, the cross-linked polymer and / or inorganic material has stable chemical properties. When used to form the shell of the core-shell structure, it can form a complete coating layer for the phase change material, preventing the phase change material from leaking during the phase change process, which is beneficial to improving the mechanical properties of the current collector.

[0044] In a second aspect, the present application provides a method for preparing the above-mentioned current collector, comprising the following steps:

[0045] mixing a phase change material and a polymer, and drying to obtain a polymer-based film including the phase change material;

[0046] A metal layer is provided on at least one side of the polymer base film to obtain a current collector.

[0047] Specifically, after the phase change material and the polymer material are mixed, the mixed material is subjected to conventional processes such as drying to prepare a polymer base film including the phase change material. A metal layer is set on at least one side of the polymer base film, which can be formed specifically by evaporation or magnetron sputtering to obtain the current collector of the present application.

[0048] Compared with the prior art, the preparation method of the current collector provided in the present application is simple, easy to operate, has low energy consumption, and is easy to mass produce.

[0049] In some embodiments, mixing the phase change material and the polymer includes: melting and mixing the phase change material and the polymer at high temperature; or forming the polymer into a film and mixing the film with a solution containing the phase change material; or mixing the polymer and the phase change material for grafting or copolymerization.

[0050] Specifically, high-temperature melt mixing of the phase change material and the polymer refers to melting the phase change material and the polymer at high temperature, and then obtaining a polymer base film by melt extrusion, molding, and drying. The high-temperature melting temperature can be but is not limited to 240°C, 260°C, 340°C or a range composed of any two of them, which can be determined according to the specific phase change material and polymer material. This application does not impose specific restrictions; making the polymer into a film and mixing the film with a solution containing the phase change material refers to first processing and molding the polymer material to prepare a polymer film, mixing the phase change material with a solvent (the solvent can be specifically n-pentane, ethyl acetate, ethanol) to prepare a solution containing the phase change material, and then mixing it with the prepared polymer film so that the phase change material fills the pores of the polymer film, and obtaining a polymer base film after drying; mixing the polymer and the phase change material for grafting or copolymerization reaction refers to grafting or copolymerizing the polymer material and the phase change material to obtain a polymer having a grafted or copolymerized phase change segment, and processing and molding the polymer having the grafted or copolymerized phase change segment, and drying to obtain a polymer base film. The above preparation method is simple and easy to implement, and the prepared polymer base film has good mechanical properties and strong heat absorption capacity, which is beneficial to improving the safety performance of the battery.

[0051] In some embodiments, the high-temperature melt mixing of the phase change material and the polymer further comprises forming the phase change material into a core-shell structure and then melt mixing the core-shell structure with the polymer at high temperature.

[0052] Specifically, making the phase change material into a core-shell structure can prevent the phase change material from flowing or leaking during the phase change process, thereby improving the mechanical properties and safety performance of the current collector; at the same time, it is applicable to different types of phase change materials and has universal applicability.

[0053] In some embodiments, forming the phase change material into a core-shell structure includes: forming the phase change material and an inorganic material into a core-shell structure through a sol-gel method; and / or forming the phase change material and a cross-linked polymer into a core-shell structure through an emulsion polymerization method or an interfacial polymerization method.

[0054] Specifically, the method of making the phase change material into a core-shell structure may vary depending on the shell material and can be adjusted according to the specific application situation; however, this application does not impose any special restrictions on this, as long as a core-shell structure with the phase change material as the core can be formed.

[0055] In some embodiments, disposing the metal layer on at least one side of the surface of the polymer base film includes: forming the metal layer on at least one side of the surface of the polymer base film by evaporation or magnetron sputtering.

[0056] Specifically, evaporation involves evaporating metal into vapor under a vacuum, which is then cooled and condensed onto the surface of a polymer film to form a metal layer. Magnetron sputtering, a type of physical vapor deposition, involves sputtering a metal target, which is then deposited onto the surface of a polymer film to form a metal layer. The metal layer formed by evaporation or magnetron sputtering is uniform and dense, improving deposition efficiency.

[0057] In a third aspect, the present application provides an electrode comprising the current collector described in the first aspect, or a current collector prepared by the method for preparing the current collector described in the second aspect. The electrode of the present application comprising the current collector can reduce heat accumulation during use and improve the safety of the current collector.

[0058] Specifically, the electrode described in the present application can be either a positive electrode or a negative electrode, and can be adapted to different application scenarios by changing the metal layer.

[0059] When the electrode of the present application is a positive electrode, the positive electrode includes a positive electrode current collector and a positive electrode active layer located on at least one side surface of the positive electrode current collector. Specifically, the positive electrode active layer can be provided on one side surface in the thickness direction of the positive electrode current collector, or the positive electrode active layer can be provided on the surfaces of two opposite sides in the thickness direction of the positive electrode current collector. The metal layer of the positive electrode current collector can be at least one of aluminum, nickel, stainless steel, titanium, gold, molybdenum and tungsten. The polymer in the polymer base film can be at least one of polypropylene, polyethylene terephthalate and polyimide. The phase change material can be at least one of n-tetracosane, aliphatic hydrocarbons with a carbon number greater than 24, beeswax, 1-hexadecanol, a monoalcohol with a carbon number greater than 16, stearic acid, erythritol, pentaerythritol, trimethylolethane, pyromellitic acid, trimethylolpropane tristearate, pentaerythritol tetrastearate and dipentaerythritol hexaoctanoate.

[0060] Specifically, the positive electrode active layer may include a positive electrode active material, a conductive agent and a binder. In the positive electrode active layer, the mass percentage of the positive electrode active material may be 70% to 99%, for example, 70%, 75%, 80%, 85%, 90%, 93%, 95%, 97%, 99% or a range consisting of any two thereof; the mass fraction of the conductive agent may be 0.5% to 15%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 8%, 10%, 13%, 15% or a range consisting of any two thereof; the mass fraction of the binder may be 0.5% to 15%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 8%, 10%, 13%, 15% or a range consisting of any two thereof.

[0061] In the embodiment of the present application, the conductive agent in the positive electrode active layer can be a conventional conductive material in the art. For example, the conductive agent in the positive electrode active layer includes one or more of carbon nanotubes, carbon black, graphene, carbon fiber, acetylene black, Ketjen black, graphite microsheets, etc.; the binder in the positive electrode active layer can be a conventional binding material in the art. For example, the binder in the positive electrode active layer can include one or more of polyvinylidene fluoride (PVDF), polyvinylidene fluoride, polyvinyl fluoride, polyethylene, polypropylene, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, etc.

[0062] In some embodiments of the present application, the positive electrode active layer may further include at least one of a dispersant, a stabilizer, a leveling agent, and other functional additives. The present application does not impose any specific restrictions on the weight percentage of these additives; they may be selected based on actual conditions. In some embodiments, the weight percentage of these functional additives in the positive electrode active material may be 0.1% to 15%.

[0063] In the embodiments of the present application, the positive electrode sheet can be prepared by conventional methods in the art, such as by a coating method. Specifically, the components used to form the positive electrode active layer, such as the positive electrode active material, the conductive agent, and the binder, can be dispersed in a solvent, such as N-methylpyrrolidone (NMP), to prepare a positive electrode slurry, which is then coated on the surface of the positive electrode current collector provided in the embodiments of the present application. After drying, rolling, and other processes, the positive electrode sheet is prepared. The coating, drying, and rolling processes involved are conventional operations for preparing positive electrode sheets using a coating method and are not particularly limited thereto.

[0064] In some embodiments, the battery may be a lithium-ion battery or a sodium-ion battery.

[0065] In some embodiments, the battery is a lithium-ion battery, and the positive electrode active material may include LiCoO2, LiNiO2, LiCo x Ni 1-x O2(0≤x≤1), LiCo x Ni 1-x-y Al y O2(0≤x≤1,0≤y≤1), LiMn2O4, LiFe x Mn y M z O4 (M is one or more of Al, Mg, Ga, Cr, Co, Ni, Cu, Zn or Mo, 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1), Li 1+x L 1－y－z M y N z O2 (L, M, N is one or more of Li, Co, Mn, Ni, Fe, Al, Mg, Ga, Ti, Cr, Cu, Zn, Mo, F, I, S, B, -0.1≤x≤0.2, 0≤y≤1, 0≤z≤1, 0≤y+z≤1), LiFePO4, Li3V2(PO4)3, Li3V3(PO4)3, LiVPO4F, Li2CuO2, Li5FeO4, and metal sulfides and oxides (such as TiS2, V2S3, FeS, FeS2, LiMS x (M is at least one transition metal element such as Ti, Fe, Ni, Cu, Mo, 1≤x≤2.5), one or more of TiO2, Cr3O8, V2O5, MnO2, etc.

[0066] When the battery is a sodium ion battery, the positive electrode active material includes but is not limited to: transition metal oxides, polyanionic compounds, organic polymers, Prussian blue materials or a combination of several thereof.

[0067] When the electrode of the present application is a negative electrode, the negative electrode includes a negative electrode current collector and a negative electrode active layer located on at least one side of the negative electrode current collector. Specifically, the negative electrode active layer can be provided on one side of the negative electrode current collector in the thickness direction, or on two opposite sides of the negative electrode current collector in the thickness direction. The metal layer of the negative electrode current collector can be at least one of copper, nickel, titanium, gold, molybdenum, tungsten, and stainless steel. The polymer in the polymer-based film can be polypropylene and / or polyimide. The phase change material can be at least one of n-tetracosane, an aliphatic hydrocarbon having more than 24 carbon atoms, beeswax, 1-hexadecanol, a monoalcohol having more than 16 carbon atoms, stearic acid, erythritol, pentaerythritol, trimethylolethane, pyromellitic acid, trimethylolpropane tristearate, pentaerythritol tetrastearate, and dipentaerythritol hexaoctanoate.

[0068] Specifically, the negative active layer includes a negative active material, a conductive agent, and a binder, and the mass percentage of the negative active material in the negative active layer can be 70% to 99%, such as 70%, 75%, 80%, 85%, 90%, 93%, 95%, 97%, 99%, or a range consisting of any two of them, the mass fraction of the conductive agent can be 0.5% to 15%, such as 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 8%, 10%, 13%, 15%, or a range consisting of any two of them, and the mass fraction of the binder can be 0.5% to 15%, such as 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 8%, 10%, 13%, 15%, or a range consisting of any two of them.

[0069] In some embodiments, the negative active material can be any negative active material known in the art, for example, natural graphite, artificial graphite, or other new negative electrode materials such as silicon-based materials; the conductive agent in the negative active layer can be any negative electrode suitable conductive agent known in the art; for example, the conductive agent in the negative active layer includes one or more of carbon nanotubes, carbon black, graphene, carbon fibers, acetylene black, ketjen black, graphite microsheet, etc.; the binder in the negative active layer can be any negative electrode suitable binder known in the art, for example, the binder in the negative active layer includes at least one of polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), sodium carboxymethyl cellulose (CMC), tetrafluoroethylene and its copolymer, polyvinylidene fluoride and its copolymer, polyolefin and its copolymer (for example, polyethylene-polyethylene glycol block copolymer, etc.), polyether and its copolymer (for example, polyethylene oxide, etc.), polyphenyl ether and its copolymer, polysiloxane and its copolymer (for example, polydimethylsiloxane, poly(dimethylsiloxane-co-alkylmethylsiloxane), etc.), polyester and its copolymer (for example, polyvinyl ester, polyvinyl acetate, polyacrylate, etc.), carboxymethyl cellulose, butadiene rubber, nitrile rubber, polyacrylic acid (PAA). Specifically, the polyolefin includes one or more of polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinylidene fluoride copolymer, propylene / vinylidene fluoride copolymer; the polytetrafluoroethylene and its copolymer can be at least one of tetrafluoroethylene / ethylene copolymer, tetrafluoroethylene / propylene copolymer, tetrafluoroethylene / vinylidene fluoride copolymer, tetrafluoroethylene / ether copolymer, tetrafluoroethylene / branched polyether copolymer, tetrafluoroethylene / vinyl ether copolymer, tetrafluoroethylene / branched polyether / vinyl ether copolymer, tetrafluoroethylene / siloxane copolymer.

[0070] In the embodiments of the present application, the negative electrode sheet can be prepared by a dry process (i.e., the material for forming the negative electrode active layer is rolled into a film and then compounded with the negative electrode current collector provided in the embodiments of the present application to prepare the negative electrode sheet), or by a wet process (coating method) (i.e., the negative electrode slurry for forming the negative electrode active layer is coated on the surface of the negative electrode current collector, and then dried, rolled, etc. to form a negative electrode active layer on the surface of the negative electrode sheet to prepare the negative electrode sheet).

[0071] In a fourth aspect, the present application provides a battery comprising the electrode described in the third aspect, which can reduce heat accumulation and heat diffusion inside the battery, lower the battery temperature, and improve the safety performance of the battery.

[0072] Generally, a battery includes an electrolyte, a cell, and a shell that encapsulates the cell. The electrolyte is injected into the cell within the shell. The cell includes a positive electrode, a negative electrode, and a separator located between the positive and negative electrodes. The positive and negative electrodes include the positive and negative electrodes described in the third aspect of this application. The cell can be a laminated cell, i.e., a cell composed of a positive electrode, a separator, and a negative electrode alternately stacked; or a wound cell, i.e., a cell composed of a positive electrode, a separator, and a negative electrode stacked and then wound.

[0073] The electrolyte of the embodiment of the present application can be a conventional electrolyte in the field. For example, the electrolyte is a non-aqueous electrolyte, which may specifically include an organic solvent, an additive and an electrolyte salt. The organic solvent may include, for example, one or more of ethylene carbonate (EC), diethyl carbonate (DEC) and propylene carbonate (PC), the additive may include, for example, fluoroethylene carbonate (FEC), the additive may include, for example, vinylene carbonate (VC), the electrolyte salt may include a lithium salt, the lithium salt may include, for example, lithium hexafluorophosphate (LiPF6), etc., but is not limited thereto.

[0074] In the embodiments of the present application, the separator is used to separate the positive electrode and the negative electrode to prevent the positive electrode and the negative electrode from short-circuiting. In the embodiments of the present application, conventional separators in the art can be used without particular limitation. For example, one or more materials selected from polyethylene, polypropylene, and polyvinylidene fluoride can be used as the separator.

[0075] In the embodiment of the present application, conventional shell materials in the art may be used to encapsulate the battery cell. The shell may include, for example, a soft packaging material such as an aluminum-plastic film, but is not limited thereto.

[0076] The battery of the present application can include a battery monomer form, a battery module form and a battery pack form. In some embodiments, the battery monomer can be assembled into a battery module, and the number of battery monomers contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module. In some embodiments, the battery module can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0077] The positive active material lithium iron phosphate (LiFePO4), the conductive agent (CNT), and the binder (PVDF) are mixed in a mass ratio of 97:1:2, and then the powder and NMP are stirred into a positive electrode slurry using a homogenizer and uniformly coated on an aluminum foil.

[0078] Vinyl carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) are mixed in a volume ratio of 1:1:1, and 1M LiPF6 is added to prepare an electrolyte containing 1M LiPF6.

[0079] The battery of the present application can include a battery monomer form, a battery module form and a battery pack form. In some embodiments, the battery monomer can be assembled into a battery module, and the number of battery monomers contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module. In some embodiments, the battery module can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0080] The specific type of battery of the present application is not particularly limited, for example, from the perspective of shape, the battery includes but is not limited to square cell, soft pack battery and cylindrical battery, etc., and the present application does not make special limitation. From the perspective of the pole core structure, the pole core of the battery can be a winding type pole core (i.e. the positive plate, negative plate and separator are stacked and then wound to form a pole core), or a laminated pole core (i.e. a plurality of positive plates, negative plates and separators are stacked to form a pole core).

[0081] In a fifth aspect, the present application provides a power consuming device comprising the battery of the fourth aspect described above. By using the battery as above in the power consuming device, the power can be continuously and stably output to supply the power consuming device, the use temperature of the power consuming device is reduced, the heat diffusion is reduced, and the safety performance of the power consuming device is improved.

[0082] The electrical equipment provided in this application can be conventional electrical equipment in this field, such as power equipment (such as electric vehicles, electric cars), electrical equipment (such as mobile phones, tablet computers, laptops, digital cameras, etc.), wearable devices (such as watches, bracelets, VR glasses, etc.), energy storage power stations, etc., without special restrictions.

[0083] The present invention is further described in detail below by way of examples.

[0084] Example 1

[0085] This embodiment is used to illustrate the current collector and its preparation method, electrode, and battery disclosed in the present invention, and includes the following steps:

[0086] (1) Preparation of positive electrode

[0087] Preparation of the positive electrode current collector: The phase change material (the phase change material exists in the form of a core-shell structure, the core is n-tricontanede, the shell is urea-formaldehyde resin, and the core-shell structure is formed by emulsion polymerization) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), and after melting, they are extruded and dried to obtain a polymer base film. The thickness of the polymer base film is 8μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on the surfaces of both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1μm.

[0088] The positive electrode active material lithium iron phosphate LiFePO4, the conductive agent (conductive carbon black SP), and the binder (PVDF) are mixed in a ratio of 97:1:2. The powder and NMP are stirred into a positive electrode slurry in a homogenizer and evenly coated on the positive electrode collector prepared above. After rolling, the positive electrode sheet of the battery is obtained.

[0089] (2) Preparation of negative electrode

[0090] Preparation of the negative electrode current collector: The phase change material (the phase change material exists in the form of a core-shell structure, the core is n-tricontanedane, the shell is urea-formaldehyde resin, and the core-shell structure is formed by emulsion polymerization) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), and after melting, they are extruded and dried to obtain a polymer base film. The thickness of the polymer base film is 4μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically a copper layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1μm.

[0091] The negative electrode active material artificial graphite, conductive agent (carbon nanotubes), thickener (CMC), binder (SBR), and toughening agent (PAA) are mixed in a ratio of 96:1:1:1:1. The powder and deionized water are stirred into a negative electrode slurry using a homogenizer and evenly coated on the negative electrode current collector prepared above. After rolling, the negative electrode sheet of the battery is obtained.

[0092] (3) Preparation of electrolyte: Ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 1:1:1 to prepare an electrolyte containing 1M LiPF6.

[0093] (4) Preparation of batteries: A polypropylene diaphragm is selected, and the positive electrode sheets, negative electrode sheets, and electrolyte prepared above are prepared into a laminated battery with a capacity of 1.7 Ah (the positive electrode sheets, polypropylene diaphragm, and negative electrode sheets are stacked alternately to prepare a laminated battery cell, and then the battery cell is placed in an aluminum-plastic film, and after conventional processes such as liquid injection (i.e., injection of electrolyte) and packaging, a laminated battery is prepared).

[0094] Example 2

[0095] The difference between Example 2 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0096] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8 μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0097] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0098] Example 3

[0099] The difference between Example 3 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0100] Preparation of the positive electrode current collector: The phase change material (specifically n-tetracosane) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by vapor deposition, and the thickness of the metal layer on one side is 1μm.

[0101] Preparation of the negative electrode current collector: The phase change material (specifically n-tetracosane) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by vapor deposition. The thickness of the metal layer on one side is 1 μm.

[0102] Example 4

[0103] The difference between Example 4 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0104] Preparation of the positive electrode current collector: The phase change material (specifically D-mannitol) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by vapor deposition, and the thickness of the metal layer on one side is 1μm.

[0105] Preparation of the negative electrode current collector: The phase change material (specifically D-mannitol) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically a copper layer) is formed on both sides of the polymer base film by vapor deposition. The thickness of the metal layer on one side is 1μm.

[0106] Example 5

[0107] The difference between Example 5 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0108] Preparation of the positive electrode current collector: The polymer (specifically polyethylene terephthalate (PET)) is first processed into a shape, dried to obtain a polymer film without a phase change material, and then mixed with a solution of a phase change material (specifically n-triacetane) (the solvent is ethyl acetate), and dried to obtain a polymer base film containing a phase change material. The thickness of the polymer base film is 8 μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically an aluminum layer) is then formed on both sides of the polymer base film by vapor deposition, and the thickness of the metal layer on one side is 1 μm.

[0109] Preparation of the negative electrode current collector: The polymer (specifically polypropylene (PP)) is first processed into a shape, dried to obtain a polymer film without phase change material, and then mixed with a solution of phase change material (specifically n-tricontane) (the solvent is ethyl acetate), and dried to obtain a polymer base film containing phase change material. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically a copper layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0110] Example 6

[0111] The difference between Example 6 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0112] Preparation of the positive electrode current collector: The phase change material (specifically n-docosane) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by vapor deposition, and the thickness of the metal layer on one side is 1μm.

[0113] Preparation of the negative electrode current collector: The phase change material (specifically n-docosane) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1μm.

[0114] Example 7

[0115] The difference between Example 7 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0116] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8 μm, and the mass percentage of the phase change material in the polymer base film is 1%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0117] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 1%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0118] Example 8

[0119] The difference between Example 8 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0120] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8 μm, and the mass percentage of the phase change material in the polymer base film is 50%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0121] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 50%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 1 μm.

[0122] Example 9

[0123] The difference between Example 9 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0124] Preparation of the positive electrode current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polyethylene terephthalate (PET)) were mixed by high-temperature melting (temperature 260°C), and after melting, the polymer base film was obtained by extrusion molding and drying, the thickness of the polymer base film was 8 μm, the mass percentage of the phase change material in the polymer base film was 20%, and then a metal layer (specifically, an aluminum layer) was formed on both sides of the surface of the polymer base film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0125] Preparation of the negative electrode current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polypropylene (PP)) were mixed by high-temperature melting (temperature 240°C), and after melting, the polymer base film was obtained by extrusion molding and drying, the thickness of the polymer base film was 4 μm, the mass percentage of the phase change material in the polymer base film was 20%, and then a metal layer (specifically, a copper layer) was formed on both sides of the surface of the polymer base film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0126] Example 10

[0127] The difference between Example 10 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, specifically as follows:

[0128] Preparation of the positive electrode current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polyethylene terephthalate (PET)) were mixed by high-temperature melting (temperature 260°C), and after melting, the polymer base film was obtained by extrusion molding and drying, the thickness of the polymer base film was 8 μm, the mass percentage of the phase change material in the polymer base film was 0.5%, and then a metal layer (specifically, an aluminum layer) was formed on both sides of the surface of the polymer base film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0129] Preparation of the negative electrode current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polypropylene (PP)) were mixed by high-temperature melting (temperature 240°C), and after melting, the polymer base film was obtained by extrusion molding and drying, the thickness of the polymer base film was 4 μm, the mass percentage of the phase change material in the polymer base film was 0.5%, and then a metal layer (specifically, a copper layer) was formed on both sides of the surface of the polymer base film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0130] Example 11

[0131] The difference between Example 11 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, specifically as follows:

[0132] Preparation of the positive current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polyethylene terephthalate (PET)) were mixed by high-temperature melting (temperature 260°C), and after melting, the polymer-based film was obtained by extrusion molding and drying, the thickness of the polymer-based film was 6 μm, the mass percentage of the phase change material in the polymer-based film was 25%, and then a metal layer (specifically, an aluminum layer) was formed on both sides of the surface of the polymer-based film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0133] Preparation of the negative current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polypropylene (PP)) were mixed by high-temperature melting (temperature 240°C), and after melting, the polymer-based film was obtained by extrusion molding and drying, the thickness of the polymer-based film was 2 μm, the mass percentage of the phase change material in the polymer-based film was 25%, and then a metal layer (specifically, a copper layer) was formed on both sides of the surface of the polymer-based film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0134] Example 12

[0135] Example 12 differs from Example 1 in that the preparation of the positive current collector and the negative current collector is different, specifically as follows:

[0136] Preparation of the positive current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polyethylene terephthalate (PET)) were mixed by high-temperature melting (temperature 260°C), and after melting, the polymer-based film was obtained by extrusion molding and drying, the thickness of the polymer-based film was 7 μm, the mass percentage of the phase change material in the polymer-based film was 25%, and then a metal layer (specifically, an aluminum layer) was formed on both sides of the surface of the polymer-based film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0137] Preparation of the negative current collector: the phase change material (specifically, n-triacontane) and the polymer (specifically, polypropylene (PP)) were mixed by high-temperature melting (temperature 240°C), and after melting, the polymer-based film was obtained by extrusion molding and drying, the thickness of the polymer-based film was 3 μm, the mass percentage of the phase change material in the polymer-based film was 25%, and then a metal layer (specifically, a copper layer) was formed on both sides of the surface of the polymer-based film by evaporation, and the single-sided thickness of the metal layer was 1 μm.

[0138] Example 13

[0139] Example 13 differs from Example 1 in that the preparation of the positive current collector and the negative current collector is different, specifically as follows:

[0140] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8 μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 0.5 μm.

[0141] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 0.5 μm.

[0142] Example 14

[0143] The difference between Example 14 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0144] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 2.5μm.

[0145] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 2.5 μm.

[0146] Example 15

[0147] The difference between Example 15 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0148] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8 μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 0.1 μm.

[0149] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4 μm, and the mass percentage of the phase change material in the polymer base film is 25%. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 0.1 μm.

[0150] Example 16

[0151] The difference between Example 16 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0152] Preparation of the positive electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polyethylene terephthalate (PET)) are mixed by high-temperature melting (temperature 260°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 8μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically an aluminum layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 3μm.

[0153] Preparation of the negative electrode current collector: The phase change material (specifically n-tricontaneda) and the polymer (specifically polypropylene (PP)) are mixed by high-temperature melting (temperature 240°C), extruded and dried after melting to obtain a polymer base film. The thickness of the polymer base film is 4μm, and the mass percentage of the phase change material in the polymer base film is 25%. Then, a metal layer (specifically a copper layer) is formed on both sides of the polymer base film by evaporation, and the thickness of the metal layer on one side is 3μm.

[0154] Comparative Example 1

[0155] The difference between Comparative Example 1 and Example 1 is that the preparation of the positive electrode current collector and the negative electrode current collector is different, as follows:

[0156] Preparation of the positive electrode current collector: The polymer (specifically polyethylene terephthalate (PET)) is processed and shaped, and dried to obtain a polymer base film with a thickness of 8 μm. A metal layer (specifically an aluminum layer) is then formed on both sides of the polymer base film by vapor deposition, and the thickness of the metal layer on one side is 1 μm.

[0157] Preparation of the negative electrode current collector: The polymer (specifically polypropylene (PP)) is processed and formed, and dried to obtain a polymer base film with a thickness of 4 μm. A metal layer (specifically a copper layer) is then formed on both sides of the polymer base film by vapor deposition, and the thickness of the metal layer on one side is 1 μm.

[0158] The batteries prepared in Examples 1-16 and Comparative Example 1 were tested using the following test methods. The test data are shown in Table 2.

[0159] Test Method

[0160] Thermal diffusion test: Figure 2 As shown, two identical batteries (U1 and U2) prepared in Examples 1-16 and Comparative Example 1 were fixed together using a clamp, a heating plate was used to induce thermal runaway in one battery (U1), and the temperature T1 at the center of the large surface of the heating plate, the temperature T2 at the center of the large surface of the runaway battery (U1) away from the heating side, and the temperature T3 at the center of the large surface of the battery (U2) that was not actively induced to thermal runaway were measured.

[0161] Table 1

[0162]

[0163] Table 2

[0164]

[0165]

[0166] From the data in Table 2, it can be found that when the current collector provided in the embodiment of the present application is used in a battery, the phase change material can absorb a large amount of heat, reduce the temperature of the battery, and improve the safety performance of the battery.

[0167] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A current collector, characterized in that: The invention comprises a polymer base film and a metal layer arranged on at least one side of the polymer base film, wherein the polymer base film comprises a phase change material.

2. The current collector according to claim 1, characterized in that The phase change material includes at least one of polybasic aliphatic hydrocarbons, fatty alcohols, fatty acids, polyols, polyacids and polyesters.

3. The current collector according to claim 2, characterized in that The phase change material includes at least one of n-tetracosane, aliphatic hydrocarbons with a carbon number greater than 24, beeswax, 1-hexadecanol, monoalcohols with a carbon number greater than 16, stearic acid, D-mannitol, erythritol, pentaerythritol, trimethylolethane, pyromellitic acid, trimethylolpropane tristearate, pentaerythritol tetrastearate, ethyl stearate and dipentaerythritol hexaoctanoate.

4. The current collector according to any one of claims 1 to 3, characterized in that: The polymer base film includes a polymer, and the polymer includes at least one of polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, poly(p-phenylene terephthalamide), polyimide, polycarbonate, polyether ketone, polyoxymethylene, polyphenylene sulfide, polyphenylene oxide, polyvinyl chloride, polyamide and polytetrafluoroethylene; and / or the metal layer includes at least one of aluminum, copper, nickel, titanium, gold, molybdenum, tungsten and stainless steel.

5. The current collector according to claim 4, characterized in that The polymer includes at least one of polypropylene, polyethylene terephthalate and polyimide; and / or the metal layer includes aluminum and / or copper.

6. The current collector according to any one of claims 1 to 5, characterized in that: The thickness of the polymer base film is 2um-8um; and / or the thickness of the metal layer is 0.5um-2.5um.

7. The current collector according to any one of claims 1 to 6, characterized in that: The number average molecular weight of the phase change material is less than or equal to 1000 g / mol; and / or the phase change temperature T m Meet: 50℃≤T m ≤200℃.

8. The current collector according to any one of claims 1 to 7, characterized in that: The phase change material accounts for 1% to 50% by mass of the polymer base film.

9. The current collector according to claim 8, characterized in that The phase change material accounts for 20% to 50% by mass of the polymer-based film.

10. The current collector according to any one of claims 4 to 9, characterized in that: The phase change material is grafted onto the polymer; and / or the phase change material is copolymerized with the polymer.

11. The current collector according to any one of claims 4 to 9, characterized in that: The phase change material exists in the form of a core-shell structure, the core of the core-shell structure includes the phase change material, and the shell of the core-shell structure includes a cross-linked polymer and / or an inorganic material.

12. The current collector according to claim 11, characterized in that The cross-linked polymer includes at least one of polymethyl methacrylate, polystyrene, urea-formaldehyde resin, polyurethane and polyurea; and the inorganic material includes silicon dioxide and / or titanium dioxide.

13. A method for preparing a current collector according to any one of claims 1 to 12, characterized in that: The following steps are involved: mixing a phase change material and a polymer, and drying to obtain a polymer-based film including the phase change material; A metal layer is provided on at least one side of the polymer base film to obtain the current collector.

14. The method for preparing a current collector according to claim 13, wherein: The mixing of the phase change material and the polymer includes: melting and mixing the phase change material and the polymer at high temperature; or making the polymer into a film and mixing the film with a solution containing the phase change material; or mixing the polymer and the phase change material for grafting or copolymerization.

15. The method for preparing a current collector according to claim 14, wherein: The step of melt-mixing the phase change material and the polymer at high temperature includes forming the phase change material into a core-shell structure and melt-mixing the core-shell structure with the polymer at high temperature.

16. The method for preparing the current collector according to claim 15, characterized in that: The forming of the phase change material into a core-shell structure includes: forming the phase change material and the inorganic material into a core-shell structure by a sol-gel method; and / or forming the phase change material and the cross-linked polymer into a core-shell structure by an emulsion polymerization method or an interfacial polymerization method.

17. The method for preparing a current collector according to any one of claims 13 to 16, characterized in that: The step of providing a metal layer on at least one side of the surface of the polymer base film comprises: forming the metal layer on at least one side of the surface of the polymer base film by evaporation or magnetron sputtering.

18. An electrode, characterized in that: The present invention comprises the current collector according to any one of claims 1 to 12, or the current collector prepared by the preparation method of the current collector according to any one of claims 13 to 17.

19. A battery, characterized in that: Comprising the electrode according to claim 18.

20. An electrical device, characterized in that: Including the battery according to claim 19.

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