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

Abstract

The embodiment of the invention provides a current collector and a preparation method thereof, an electrode and a battery, the current collector comprises a current collector body and a carbon-coated layer, the carbon-coated layer is arranged on the surface of at least one side of the current collector body along the thickness direction of the current collector body, the carbon-coated layer comprises a binder, and the binder comprises an ethylene-acrylic acid copolymer. According to the current collector provided by the embodiment of the invention, the ethylene-acrylic acid copolymer is selected as the binder, and the drying temperature of the carbon coating layer in the preparation process can be reduced, so that the adverse effect on the current collector body in the preparation process is avoided, the deformation of the current collector body is avoided, the quality of the current collector is higher, the yield is improved, and meanwhile, the production cost is reduced.

Description

Technical Field

[0001] This application relates to the field of current collector technology, and in particular to a current collector and its preparation method, electrode, battery and power device. Background Technology

[0002] Current collectors are a crucial component of batteries, serving to carry active materials and collect microcurrents. Unlike conventional pure metal current collectors (aluminum, copper, and alloys), composite current collectors, with their "metal-polymer-metal" structure, offer lower cost and higher safety. However, the thinner metal layer in composite current collectors results in lower overcurrent capacity, leading to a decrease in the rate performance of the battery cell. Carbon coating on composite current collectors can effectively improve the battery's high-rate charge and discharge capabilities.

[0003] However, carbon coating pastes usually require high drying temperatures. During drying, the polymer substrate of the composite current collector is prone to shrinkage at high temperatures, resulting in low yield and high consumption of carbon-coated composite current collectors. Summary of the Invention

[0004] This application provides a current collector and its preparation method, an electrode, a battery, and an electrical device, aiming to reduce the drying temperature of the carbon coating layer and avoid shrinkage problems in the current collector.

[0005] In a first aspect, embodiments of this application provide a current collector, including a current collector body and a carbon coating layer, the carbon coating layer being disposed on at least one side surface of the current collector body along its thickness direction, the carbon coating layer including an adhesive, the adhesive including an ethylene-acrylic acid copolymer.

[0006] The current collector provided in this application uses ethylene-acrylic acid copolymer as a binder, which can reduce the drying temperature of the carbon coating layer during the preparation process. Therefore, it will not have an adverse effect on the current collector body during the preparation process, avoid deformation of the current collector body, improve the quality of the current collector, increase the yield, and reduce production costs.

[0007] In some embodiments, the adhesive further includes at least one of ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer.

[0008] The boiling points of ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer are lower than those of ethylene-acrylic acid copolymer. By introducing the above copolymers into the binder, the drying temperature during the preparation of the carbon coating layer of the current collector can be further reduced, thus further reducing the probability of affecting the current collector body during the preparation process.

[0009] In some embodiments, the thickness of the carbon coating layer is 0.4 μm to 5 μm, and the mass fraction of the binder in the carbon coating layer is 5% to 95%.

[0010] At this thickness, the carbon coating layer can effectively improve the high-rate charge and discharge capability of the battery without excessively increasing the thickness of the current collector. By reasonably controlling the mass fraction of the binder, the drying temperature during the preparation of the carbon coating layer can be more controllable, thus ensuring that the current collector body is not affected during the preparation process.

[0011] In some embodiments, the conductive agent includes at least one of Ketjen black, graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black, acetylene black, furnace black, and whisker carbon nanotubes.

[0012] The aforementioned conductive agent, after being mixed with the binder to form a slurry, has a lower drying temperature, which makes the drying temperature more controllable during the preparation of the carbon coating layer, thereby ensuring that the current collector body is not affected during the preparation process.

[0013] Secondly, embodiments of this application also provide a method for preparing a current collector, comprising: mixing a conductive agent, an adhesive, and a solvent to form a slurry, wherein the adhesive includes an ethylene-acrylic acid copolymer; coating the current collector body with the slurry on one side surface along its thickness direction; and drying the current collector body coated with the slurry.

[0014] The current collector preparation method provided in this application uses ethylene-acrylic acid copolymer as a binder, which can reduce the drying temperature of the carbon coating layer during the preparation process. Therefore, it will not have an adverse effect on the current collector body during the preparation process, avoid deformation of the current collector body, improve the quality of the current collector, increase the yield, and reduce production costs.

[0015] In some embodiments, the method further includes: coating the slurry onto the other side surface of the manifold body along its thickness direction; and drying the manifold body coated with the slurry at a temperature of 50°C to 80°C.

[0016] The above method can prepare a current collector with carbon coating on both sides, and the carbon coating on each side will not affect the current collector body during the preparation process. At the above drying temperature, the slurry can be dried with a high drying rate, and at this temperature, it will not affect the current collector body.

[0017] In some embodiments, after the slurry is formed, the method further includes grinding the slurry.

[0018] By grinding the slurry, the probability of agglomeration of the conductive agent in the slurry can be reduced, and the particle size can be reduced, so that the conductive agent and binder in the slurry are more evenly dispersed. When coated onto the current collector, the thickness is more uniform. Therefore, the drying process can be completed simultaneously. The current collector is less affected by temperature, the time is short, the efficiency is high and the production cost is low.

[0019] Thirdly, embodiments of this application also provide an electrode, the electrode comprising the aforementioned current collector.

[0020] The electrodes described above use the aforementioned current collector. Since the current collector has higher quality and lower production cost, the electrodes also have higher quality and lower production cost.

[0021] Fourthly, embodiments of this application also provide a battery, the battery including the electrodes described above.

[0022] The battery described above uses the aforementioned electrodes. Because the electrodes are of higher quality and have lower production costs, the battery itself is of higher quality and has lower production costs.

[0023] Fifthly, embodiments of this application also provide an electrical device, which includes the battery described above.

[0024] The aforementioned electrical device uses the aforementioned battery. Because the battery has higher quality and lower production cost, the electrical device has higher quality and lower production cost. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a current collector structure provided in an embodiment of this application. Detailed Implementation

[0026] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] Traditional current collectors use metal foil as the manufacturing material. In contrast, composite current collectors employ a "sandwich" structure of "metal-polymer material-metal," using polymers such as PET (polyethylene terephthalate), PP (polypropylene), and PI (polyimide) as the intermediate substrate, with two layers of deposited metal. Compared to traditional current collectors, composite current collectors offer advantages such as high safety, long lifespan, high energy density, and low cost. Coating the metal foil surface with conductive materials primarily serves three purposes: first, it makes the foil surface more uniform, increasing the specific surface area and improving the bonding area between the current collector and the active material; second, the conductive carbon layer, as a coating material, improves the conductivity of the electrode and reduces the battery's internal resistance; and third, it enhances the adhesion between the active material and the current collector, reducing the problem of active particle shedding during electrode cycling. The thinner metal layer in composite current collectors results in lower overcurrent capacity, leading to a decrease in the rate performance of the battery cell. Coating the composite current collector with carbon can effectively improve the battery's high-rate charge and discharge capabilities.

[0028] Currently, carbon coating pastes typically require high drying temperatures. When processing composite current collectors, the polymer substrate is prone to shrinkage, resulting in low yield and high consumption of carbon-coated composite current collectors.

[0029] Based on this, embodiments of this application provide a current collector and its preparation method, an electrode, and a battery, in order to improve the above-mentioned technical problems.

[0030] Firstly, see Figure 1 This application provides a current collector 10, including a current collector body 6 and a carbon coating layer 1. The carbon coating layer 1 is disposed on at least one surface of the current collector body 6 along its thickness direction. The current collector body 6 is a composite current collector structure, comprising a first metal layer 2, a composite material layer 3, and a second metal layer 4. The first metal layer 2 and the second metal layer 4 are respectively disposed on opposite sides of the composite material layer 3, forming a "sandwich" structure. The composite material layer 3 comprises one or more materials selected from polyethylene (PE), polyethylene terephthalate (PET), polyimide (PI), polypropylene (PP), polyamide (PA), polyphenylene sulfide (PPS), and polyethylene naphthalate (PEN). The thickness of the composite material layer 3 can be, for example, 2 μm to 15 μm.

[0031] The first metal layer 2 and the second metal layer 4 can be made of the same material or different materials, and this is not limited. When the current collector 10 is used to make the positive electrode of the battery, the first metal layer 2 and the second metal layer 4 can be formed of materials such as aluminum or aluminum alloy. When the current collector 10 is used to make the negative electrode of the battery, the first metal layer 2 and the second metal layer 4 can be formed of materials such as copper, nickel, copper-nickel, or copper-zinc alloy. The thickness of the first metal layer 2 and the second metal layer 4 can be, for example, 0.2 μm to 10 μm.

[0032] The carbon coating layer 1 is disposed on the surface of the current collector body 6 along its thickness direction. Specifically, the carbon coating layer 1 can be disposed on the surface of the first metal layer 2 away from the composite material layer 3, or on the surface of the second metal layer 4 away from the composite material layer 3, or simultaneously on both the surfaces of the first metal layer 2 and the second metal layer 4 away from the composite material layer 3. The thickness of the carbon coating layer 1 can be 0.4μm-5μm, for example, it can be 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, etc.

[0033] The carbon coating layer 1 includes a conductive agent and a binder. The conductive agent in the carbon coating layer 1 mainly serves to improve the electronic conductivity. The binder mainly serves to firmly adhere the active material and the conductive agent to the current collector body 6. The binder includes ethylene-acrylic acid copolymer. Ethylene-acrylic acid copolymer (EAA) is a polymer with thermoplasticity and extremely high adhesion. EAA has good adhesion and can be completely cured at a relatively low temperature. Therefore, during the processing, a high drying temperature is not required to form the carbon coating layer 1. This can reduce the impact on the composite material layer 3 in the current collector body 6 during the preparation process, improve the quality of the current collector 10, increase the yield, and reduce production costs.

[0034] In some embodiments, the binder may further include at least one of ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer. The boiling points of ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer are lower than those of ethylene-acrylic acid copolymer. By introducing these copolymers into the binder, the drying temperature during the preparation of the carbon coating layer 1 of the current collector 10 can be further reduced, thus further reducing the probability of affecting the current collector body 6 during the preparation process.

[0035] In this application, the conductive agent includes at least one of Ketjen black, graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black, acetylene black, furnace black, and whisker carbon nanotubes. The aforementioned conductive agents, after being mixed with the binder to form a slurry, require a lower drying temperature, allowing for more controllable drying temperature control during the preparation of the carbon coating layer 1, thereby ensuring that the current collector 6 is not affected during the preparation process.

[0036] In some implementations, the composition of the binder in the current collector can be detected by Fourier transform infrared spectroscopy (FT-IR).

[0037] Secondly, this application also provides a method for preparing the above-mentioned current collector 10, including mixing a conductive agent, an adhesive and a solvent to form a slurry, wherein the adhesive includes an ethylene-acrylic acid copolymer; coating the current collector body with the slurry on one side surface along its thickness direction; and drying the current collector body coated with the slurry.

[0038] The solvent ensures that the conductive agent and binder are mixed evenly and coated uniformly onto the surface of the current collector during the coating process. The solvent evaporates during the subsequent drying process and does not remain in the carbon coating layer. The above preparation method uses an ethylene-acrylic acid copolymer as the binder, which lowers the drying temperature of the carbon coating layer during preparation. Therefore, it does not adversely affect the current collector during preparation, avoids deformation of the current collector, results in higher quality current collectors, improves yield, and reduces production costs.

[0039] The above preparation method can produce a current collector with a carbon coating layer on one side. To further produce a current collector with a carbon coating layer on both sides, the above preparation method can further include the following steps: coating the current collector body with the slurry on the other side along its thickness direction; and drying the current collector body coated with the slurry. This allows for the preparation of a current collector with a carbon coating layer on both sides, and the carbon coating layer on each side does not affect the current collector body during the preparation process.

[0040] During the preparation of the slurry, it can also be ground. The purpose of grinding is to reduce the likelihood of agglomeration of the conductive agent in the slurry, while also reducing particle size, resulting in more uniform dispersion of the conductive agent and binder, leading to a more uniform thickness when coated onto the current collector. Specifically, a sand mill or similar equipment can be used to grind the slurry. The grinding media can be zirconium oxide with a diameter of 0.2mm-2mm, and the grinding time can be greater than or equal to 3 hours, such as 5 hours or 6 hours. The grinding speed is not limited and can be, for example, 2000 rpm or 3000 rpm.

[0041] Various coating methods can be used during the coating process, such as spraying, roller coating, and brush coating. In one embodiment, gravure coating can be used to coat the paste. Gravure coating is a coating technology based on the principle of gravure printing. It uses a gravure roller with a recessed pattern to transfer the paste to the surface of the collector body. This coating method has the advantages of good coating uniformity and precise control of coating amount.

[0042] The solvent can be a low-boiling-point solvent, such as one that evaporates rapidly at 50℃-80℃. Low-boiling-point solvents allow for low-temperature drying during the drying process, reducing the likelihood of interference with the current collector during preparation. In some embodiments, the solvent can be water, ethanol, or a mixture of water and ethanol. Both water and ethanol have good volatility, resulting in low drying temperatures and high drying efficiency. Furthermore, water and ethanol can effectively disperse the conductive agent and binder, ensuring uniform dispersion. More preferably, water and ethanol can be mixed at a volume ratio of (0~10):(0~10), or more preferably, at a volume ratio of (5~7):(5~3).

[0043] In the slurry, the mass ratio of conductive agent to binder can be 5:95 to 95:5, meaning that the binder's mass fraction in the final carbon coating layer is 5%-95%. For example, the mass ratio of conductive agent to binder can be 5:95, 10:90, 20:80, 40:60, 50:50, 60:40, 80:20, 90:10, 95:5, etc. The mass ratio of conductive agent to binder can be rationally adjusted according to different design parameters. More preferably, the mass ratio of conductive agent to binder can be 40:60 to 60:40. Within this range, the proportions of conductive agent and binder are relatively balanced, ensuring both stable adhesion of the carbon coating layer to the current collector and good conductivity.

[0044] During the drying process, the drying temperature can be controlled to avoid excessively high temperatures that could adversely affect the manifold. Preferably, the drying temperature can be 50℃-80℃. At this temperature, the slurry can be dried with a high drying rate, while the manifold will not be affected. The drying temperature can be set to, for example, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, etc.

[0045] The present application will be described in detail below with reference to specific embodiments.

[0046] Example 1 (1) Preparation of conductive paste: The conductive agent, binder, and solvent are thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent is a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder is ethylene-acrylic acid copolymer, and the solvent is a 75% aqueous ethanol solution. After mixing, the original paste is milled using a sand mill to fully disperse the agglomerates of conductive carbon to obtain the paste. The milling speed is 3000 rpm, the milling time is 5 h, and the milling medium is zirconia beads with a diameter of 0.2 mm to 2 mm.

[0047] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first metal layer and the second metal layer are 1-micron thick aluminum layers, and the composite material layer is a 6-micron thick PET polymer layer. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 80°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micron.

[0048] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the positive electrode sheet, and finally, a positive electrode sheet is obtained.

[0049] Example 2 (1) Preparation of conductive paste: The conductive agent, binder, and solvent are thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent is a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder is ethylene-acrylic acid copolymer, and the solvent is a 75% aqueous ethanol solution. After mixing, the original paste is milled using a sand mill to fully disperse the agglomerates of conductive carbon to obtain the paste. The milling speed is 3000 rpm, the milling time is 5 h, and the milling medium is zirconia beads with a diameter of 0.2 mm to 2 mm.

[0050] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first and second metal layers are copper layers with a thickness of 1 micrometer, and the composite material layer is a PET polymer layer with a thickness of 6 micrometers. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 80°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0051] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the negative electrode sheet, and finally, a negative electrode sheet is obtained.

[0052] Example 3 (1) Preparation of conductive paste: The conductive agent, binder, and solvent are thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent is a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder is a mixture of ethylene-acrylic acid copolymer and ethylene-methyl acrylate copolymer. The solvent is a 75% aqueous ethanol solution. After mixing, the original paste is milled using a sand mill to fully disperse the agglomerates of conductive carbon to obtain the paste. The milling speed is 3000 rpm, the milling time is 5 h, and the milling medium is zirconia beads with a diameter of 0.2 mm to 2 mm.

[0053] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first metal layer and the second metal layer are 1-micrometer-thick aluminum layers, and the composite material layer is a 6-micrometer-thick PET polymer layer. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 50°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0054] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the positive electrode sheet, and finally, a positive electrode sheet is obtained.

[0055] Example 4 (1) Preparation of conductive paste: The conductive agent, binder, and solvent are thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent is a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder is a mixture of ethylene-acrylic acid copolymer and ethylene-ethyl acrylate copolymer. The solvent is a 75% aqueous ethanol solution. After mixing, the original paste is milled using a sand mill to fully disperse the agglomerates of conductive carbon to obtain the paste. The milling speed is 3000 rpm, the milling time is 5 h, and the milling medium is zirconia beads with a diameter of 0.2 mm to 2 mm.

[0056] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer, and a second metal layer. The first and second metal layers are copper layers with a thickness of 1 micrometer, and the composite material layer is a PET polymer layer with a thickness of 6 micrometers. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 60°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0057] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the negative electrode sheet, and finally, a negative electrode sheet is obtained.

[0058] Comparative Example 1 (1) Preparation of conductive paste: The conductive agent, binder, and solvent are thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent is a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder is a polyurethane-based water-based adhesive, and the solvent is a 75% ethanol aqueous solution. After mixing, the original paste is milled using a sand mill to fully disperse the agglomerates of conductive carbon, thus obtaining the paste. The milling speed is 3000 rpm, the milling time is 5 hours, and the milling medium is zirconia beads with a diameter of 0.2 mm to 2 mm.

[0059] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first metal layer and the second metal layer are 1-micrometer-thick aluminum layers, and the composite material layer is a 6-micrometer-thick PET polymer layer. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 120°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0060] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the positive electrode sheet, and finally, a positive electrode sheet is obtained.

[0061] Comparative Example 2 (1) Preparation of conductive paste: The conductive agent, binder, and solvent were thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent was a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder was an acrylic water-based adhesive, and the solvent was a 75% ethanol aqueous solution. After mixing, the original paste was milled using a sand mill to fully disperse the agglomerates of conductive carbon, thus obtaining the paste. The milling speed was 3000 rpm, the milling time was 5 hours, and the milling medium was zirconia beads with a diameter of 0.2 mm to 2 mm.

[0062] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first metal layer and the second metal layer are 1-micrometer-thick aluminum layers, and the composite material layer is a 6-micrometer-thick PET polymer layer. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 120°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0063] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the positive electrode sheet, and finally, a positive electrode sheet is obtained.

[0064] Comparative Example 3 (1) Preparation of conductive paste: The conductive agent, binder, and solvent are thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent is a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder is a polyurethane-based water-based adhesive, and the solvent is a 75% ethanol aqueous solution. After mixing, the original paste is milled using a sand mill to fully disperse the agglomerates of conductive carbon, thus obtaining the paste. The milling speed is 3000 rpm, the milling time is 5 hours, and the milling medium is zirconia beads with a diameter of 0.2 mm to 2 mm.

[0065] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first and second metal layers are copper layers with a thickness of 1 micrometer, and the composite material layer is a PET polymer layer with a thickness of 6 micrometers. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 120°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0066] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the negative electrode sheet, and finally, a negative electrode sheet is obtained.

[0067] Comparative Example 4 (1) Preparation of conductive paste: The conductive agent, binder, and solvent were thoroughly mixed in a ratio of 1:1:9 to obtain the original paste. The conductive agent was a mixture of superconducting carbon black Super P and graphene in a ratio of 4:6. The binder was an acrylic water-based adhesive, and the solvent was a 75% ethanol aqueous solution. After mixing, the original paste was milled using a sand mill to fully disperse the agglomerates of conductive carbon, thus obtaining the paste. The milling speed was 3000 rpm, the milling time was 5 hours, and the milling medium was zirconia beads with a diameter of 0.2 mm to 2 mm.

[0068] (2) Selection of current collector body: The current collector body includes a first metal layer, a composite material layer and a second metal layer. The first and second metal layers are copper layers with a thickness of 1 micrometer, and the composite material layer is a PET polymer layer with a thickness of 6 micrometers. The current collector body is installed on a coating equipment, and the prepared slurry is coated on the first surface of the current collector body using gravure coating technology. The current collector body coated with conductive material is transferred into an oven and dried at 120°C for 24 hours to form a conductive slurry on the first surface of the current collector body, resulting in a single-sided carbon-coated current collector body with a carbon coating thickness controlled at 1 micrometer.

[0069] (3) The current collector with single-sided carbon coating is coated with a second surface according to the method in step 2; finally, a current collector with double-sided carbon coating is obtained. This current collector can be used as a substrate for coating the negative electrode sheet, and finally, a negative electrode sheet is obtained.

[0070] Experimental Example 1 The carbon coating layers of the current collectors obtained in Examples 1-4 were analyzed by Fourier transform infrared spectroscopy (FT-IR). Referring to Table 1, the following characteristic peaks were observed in the infrared spectra: Table 1 Infrared Spectroscopic Detection Results of Carbon Coating Layer As can be seen from the data in Table 1, the above characteristic peaks are consistent with the characteristic absorption peaks of ethylene-acrylic acid copolymer, indicating that the binder in the carbon coating layer of the current collector prepared in this application is uniformly and stably distributed.

[0071] Experimental Example 2 Sheet resistance was tested using a four-probe sheet resistance meter for the current collectors obtained in Examples 1-4 and Comparative Examples 1-4.

[0072] After coating the current collectors obtained in Examples 1 and 3 and Comparative Examples 1 and 2 with positive electrode slurry to obtain positive electrode sheets, peel strength tests were performed. The positive electrode slurry was LiNi. 0.8 Co 0.1 Mn 0.1O2, Super P, and PVDF (in a mass ratio of 95:3:2) were thoroughly stirred and homogenized in N-methylpyrrolidone solvent to obtain a positive electrode. The positive electrode was then coated onto the current collector using a coating machine. After drying and compaction, the positive electrode sheets of Examples 1 and 3 and Comparative Examples 1 and 2 were obtained. After coating the current collectors obtained in Examples 2 and 4 and Comparative Examples 3 and 4 with negative electrode slurry to obtain negative electrode sheets, peel strength tests were performed. The negative electrode slurry was obtained by thoroughly stirring graphite, Super P, and CMC (95:3:2) in deionized water. The negative electrode slurry was coated onto the current collector using a coating machine. After drying and compaction, the negative electrode sheets of Examples 2 and 4 and Comparative Examples 3 and 4 were obtained. The sheets were cut into strips of 40×100mm and their peel strength was tested using a high-precision tensile tester.

[0073] The current collector test data are shown in Table 2: Table 2 Results of Shear Resistance and Peel Force Tests In Examples 1-4, ethylene-acrylic acid copolymer was selected as the binder, requiring a lower drying temperature during the preparation process. As shown in Table 2, the sheet resistance of the current collectors obtained in Examples 1 and 3 and Comparative Examples 1 and 2 is not significantly different, and the peel strength of the prepared positive electrode sheets is also similar. The sheet resistance of the current collectors obtained in Examples 2 and 4 and Comparative Examples 3 and 4 is relatively small, and the peel strength of the prepared negative electrode sheets is similar. This indicates that even at a lower drying temperature, the carbon coating layer of the current collector can be completely dried while maintaining stable structural strength. This minimizes the impact on the current collector body during preparation, resulting in higher overall quality and yield of the current collector.

[0074] This embodiment also provides an electrode, which includes a current collector. The current collector can be any of the current collectors obtained in Embodiments 1-4. It is understood that the electrode can be a dry electrode or a wet electrode, and this application does not limit this. Furthermore, the electrode can be a positive electrode or a negative electrode. When the electrode is a positive electrode, the positive electrode material can be lithium nickel cobalt manganese oxide (LiNixMnyCozO2, x+y+z=1), lithium iron manganese phosphate (LiFexMnyPO4, x+y=1), lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium-rich manganese-based oxide, or lithium nickel manganese oxide (LiNi). 0.5 Mn 1.5 The cathode material can be lithium vanadium phosphate (Li3V2(PO4)3, lithium vanadium oxide phosphate (LiVOPO4), etc.), and the current collector can be placed on the surface of the cathode material. When the electrode is the anode, the anode material can be graphite, silicon carbon anode, silicon anode, lithium metal anode, etc., and the current collector can be placed on the surface of the anode material.

[0075] Electrodes using the aforementioned current collector have higher quality and lower production costs because the current collector has higher quality and lower production costs.

[0076] This application also provides a battery including the electrodes described above. The electrodes are those obtained in Example 5. Since the electrodes have higher quality and lower production costs, the battery also has higher quality and lower production costs.

[0077] This application also provides an electrical device, which includes the battery. The electrical device can be, for example, a new energy vehicle, an aircraft, a robot, a computer, a mobile phone, or any other product equipped with a battery.

[0078] In this application, "multiple" refers to two or more. Unless otherwise explicitly defined, the terms "installation," "connection," and "linking" should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. The terms "first," "second," "third," "fourth," etc. (if present), are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0079] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, if the method includes steps A and B, it means that the method may include steps A and B performed sequentially, or it may include steps B and A performed sequentially. For example, if the method may also include step C, it means that step C may be added to the method in any order. For example, the method may include steps A, B, and C, or it may include steps A, C, and B, or it may include steps C, A, and B, etc.

[0080] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A current collector, characterized in that, include: Current collection body; as well as A carbon coating layer is disposed on at least one side surface of the manifold body along its thickness direction, the carbon coating layer comprising an adhesive comprising an ethylene-acrylic acid copolymer.

2. The current collector according to claim 1, characterized in that, The adhesive further includes at least one of ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer.

3. The current collector according to claim 1 or 2, characterized in that, The thickness of the carbon coating layer is 0.4μm-5μm, and the mass fraction of the binder in the carbon coating layer is 5%-95%.

4. The current collector according to claim 1, characterized in that, The current collector also includes a conductive agent, which includes at least one of Ketjen black, graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black, acetylene black, furnace black, and whisker carbon nanotubes.

5. A method for preparing a current collector, characterized in that, include: A conductive agent, an adhesive, and a solvent are mixed to form a slurry, wherein the adhesive includes an ethylene-acrylic acid copolymer; The slurry is coated on one side surface of the collector body along its thickness direction; The manifold body coated with the slurry is dried.

6. The method for preparing a current collector according to claim 5, characterized in that, The method further includes: coating the slurry onto the other side surface of the manifold along its thickness direction; and drying the manifold coated with the slurry at a temperature of 50°C to 80°C.

7. The method for preparing a current collector according to claim 5 or 6, characterized in that, The solvent includes ethanol.

8. An electrode, characterized in that, The electrode includes a current collector as described in any one of claims 1-4.

9. A battery, characterized in that, The battery includes the electrodes as described in claim 8.

10. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 9.

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