Battery cell current collector, battery and preparation method of battery cell current collector

Abstract

The invention relates to a battery cell current collector, a battery and a preparation method of the battery cell current collector, and relates to the technical field of power batteries. The cell current collector comprises a base layer and a coating layer. The base layer is a metal foil. The coating layer comprises a plurality of dot matrix coating blocks, the dot matrix coating blocks are coated on the base layer in an array manner, and the dot matrix coating blocks comprise high-porosity active components. The battery cell current collector can solve the problems that the current collector is easy to corrode and separate lithium, and meanwhile, the stripping force of a pole piece is improved, so that the performance of a power battery is improved.

Description

Technical Field

[0001] This application relates to the field of power battery technology, specifically to a cell current collector, a battery, and a method for preparing the cell current collector. Background Technology

[0002] In the production and processing of power batteries, the core lies in the preparation of the battery cell. Specifically, structurally, a battery cell can be divided into a negative electrode and a positive electrode. Each electrode includes a current collector and active materials coated on the current collector. Taking the positive electrode as an example, the current collector is typically an aluminum foil structure, onto which active materials such as lithium iron phosphate are then coated.

[0003] However, the aforementioned positive electrode sheet will experience electrochemical corrosion and lithium plating during long-term use. During long-term cycling, side reactions in the electrolyte can cause localized corrosion of the aluminum foil, increasing the resistance of the current collector and leading to capacity decay of the battery cell. Simultaneously, lithium plating can also occur due to lithium ion deposition during long-term cycling.

[0004] In existing technologies, some solutions involve coating the current collector surface with a layer of graphene or other materials to improve its corrosion resistance. However, this can affect the peeling force of the positive electrode, thus affecting the coating and adhesion between the current collector and the active material, and consequently impacting the cell performance.

[0005] Therefore, there is an urgent need to provide a cell structure that can improve the problems of corrosion and lithium plating in the current collector, while increasing the peeling force of the electrode sheets, thereby improving the performance of the power battery. Summary of the Invention

[0006] The purpose of this application is to provide a current collector for a battery cell, a battery, and a method for preparing the current collector for a battery cell, which can improve the problems of corrosion and lithium plating in the current collector, while increasing the peeling force of the electrode, thereby improving the performance of the power battery.

[0007] To achieve the above objectives, in a first aspect, this application provides a current collector for a battery cell, comprising a substrate and a coating layer. The substrate is configured as a metal foil. The coating layer comprises a plurality of lattice coating blocks, the lattice coating blocks being arrayed and coated on the substrate, and the lattice coating blocks comprising a high-porosity active component.

[0008] Based on the embodiments described above, a metal foil is used as the base layer of the current collector. A coating layer containing highly porosity active components is then applied to the base layer. This high porosity of the coating layer creates a high-speed lithium-ion transport channel, allowing lithium ions to pass through quickly and improving lithium-ion deposition. This addresses the problem of lithium plating easily occurring on the current collector. Simultaneously, by applying the coating layer to the base layer surface, direct contact between the base layer and the electrolyte is reduced, thereby mitigating the electrochemical corrosion of the metal foil caused by side reactions in the electrolyte.

[0009] Furthermore, the coating layer is specifically configured as a multi-array lattice coating block. By using a discontinuous coating method, the problems of reduced electrode peeling force and reduced electronic conductivity caused by traditional continuous coating are avoided. This not only improves the problems of lithium deposition and electrochemical corrosion of the current collector, but also enhances the peeling force of the electrode and ensures the electronic conductivity of the current collector.

[0010] In summary, this application utilizes a coating layer on the substrate, leveraging its high porosity to allow lithium ions to pass through rapidly, thus mitigating issues such as lithium deposition in the current collector and susceptibility to electrochemical corrosion. Furthermore, the coating layer employs discontinuous dot-matrix coating blocks, thereby enhancing the electrode peeling force, ensuring the electronic conductivity of the current collector, and ultimately improving the performance of both the current collector and the overall battery cell.

[0011] In some embodiments, the dot matrix coating block is configured as a circular structure, and the diameter of the dot matrix coating block is d, where 50 μm ≤ d ≤ 200 μm. The spacing between any two adjacent dot matrix coating blocks is L, where 100 μm ≤ L ≤ 500 μm.

[0012] Based on the above embodiments of this application, the diameter and gap size of the dot matrix coating block are limited. By limiting the area of ​​the area covered by the coating layer and the area not covered by the coating layer on the substrate, a more suitable range is maintained. This balances the corrosion resistance, lithium plating resistance and conductivity of the current collector, keeping the various properties of the current collector within a more suitable and good range.

[0013] In some embodiments, the thickness of the dot matrix coating block is H, where 0.5 μm ≤ H ≤ 2 μm.

[0014] Based on the embodiments described above, by limiting the thickness of the lattice coating block, the specific thickness of the lattice coating block is kept within a suitable range. When the thickness of the lattice coating block is too thin, its corrosion resistance to the current collector and its ability to increase the lithium-ion throughput may be limited. Conversely, when the thickness of the lattice coating block is too large, it will affect the overall thickness of the current collector and may also result in material waste. Therefore, by limiting the thickness of the lattice coating block to a suitable range, the aforementioned problems are mitigated.

[0015] In some embodiments, the lattice coating block further includes a conductive reinforcing agent and an adhesive matrix. In the lattice coating block, the mass ratio of the high-porosity active component is 50%-60%, the mass ratio of the conductive reinforcing agent is 5%-12%, and the mass ratio of the adhesive matrix is ​​15%-40%.

[0016] Based on the embodiments described above, the coating layer composition utilizes a high-porosity active component to increase the lithium-ion throughput rate, while a conductivity enhancer is incorporated to improve the lateral conductivity of the coating layer. Furthermore, an adhesive matrix is ​​used to enhance the overall flexibility and adhesion of the coating layer, ensuring effective coating. Through the synergistic interaction of these components, various properties of the coating layer are achieved.

[0017] In some embodiments, the high-porosity active component is set as nano-alumina particles, and the particle size range of the nano-alumina particles is 50nm-200nm.

[0018] Based on the above embodiments of this application, by specifically setting the high-porosity active component as nano-alumina particles, the oxygen-rich vacancies on the surface of the nano-alumina particles are used to form high-speed lithium-ion transport channels, enabling lithium ions to pass through quickly, thereby inhibiting lithium-ion deposition, improving the lithium plating situation in the current collector, and enhancing the performance of the current collector.

[0019] In some embodiments, the conductive enhancer is at least one of graphene, carbon nanotubes, and carbon black.

[0020] Based on the embodiments described above, in practical applications, the conductivity enhancer can be any one of graphene, carbon nanotubes, and carbon black, or a mixture of these components can be used. The excellent conductivity of these materials is utilized to improve the overall lateral conductivity of the coating layer, thereby ensuring the overall conductivity of the current collector.

[0021] In some embodiments, the adhesive matrix is ​​set as polyacrylic acid.

[0022] Based on the above embodiments of this application, polyacrylic acid is used as the adhesive matrix. The strong adhesive force, chemical stability and electrolyte resistance of polyacrylic acid itself are utilized to enhance the overall adhesive force of the coating layer and ensure stable adhesion between the coating layer and the substrate.

[0023] According to a second aspect of this application, a battery is also provided, the battery comprising an active material and the aforementioned current collector, wherein the active material is coated on the current collector to form an electrode structure.

[0024] Based on the above embodiments of this application, the battery provided by this application includes the aforementioned cell current collector. Through the above arrangement, by setting a coating layer on the substrate, the high porosity of the coating layer allows lithium ions to pass through quickly, improving problems such as lithium plating in the current collector and susceptibility to electrochemical corrosion. Simultaneously, the coating layer employs discontinuous dot matrix coating blocks, thereby enhancing the peeling force of the electrode sheets, ensuring the electronic conductivity of the current collector, and thus improving the performance of both the current collector and the overall cell, ultimately enhancing the aforementioned battery performance.

[0025] According to a third aspect of this application, a method for preparing a current collector for a battery cell is also provided. This method is applicable to the preparation of the aforementioned current collector for a battery cell, and includes the following steps: Slurry preparation involves mixing high-porosity active components, conductive reinforcing agents, and adhesive matrix in a specific ratio to form a coating slurry.

[0026] Gravure printing uses a gravure roller to transfer coating paste onto the surface of a metal foil to form an array of dot-matrix coated blocks on the metal foil.

[0027] The coated metal foil and the dot matrix coating block are dried together in three stages to form the current collector of the battery cell.

[0028] Based on the above embodiments of this application, the specific preparation method of the current collector of this application has been disclosed. A coating slurry is prepared according to the above proportions. The composition of the various components in the coating slurry is used to improve problems such as lithium plating and easy electrochemical corrosion in the current collector. Subsequently, gravure printing is used to complete the coating process, which not only simplifies and speeds up the coating process but also enables rapid array coating of dot matrix coating blocks. The use of discontinuous dot matrix coating blocks enhances the peel strength of the electrode, ensuring the electronic conductivity of the current collector. Finally, through drying and curing, the shape and adhesion position of the coating layer are fixed, ultimately obtaining a current collector structure that is corrosion-resistant, lithium plating-resistant, and has high peel strength.

[0029] In some embodiments, during the gravure printing step, the cell depth of the gravure roller is 30μm-50μm, and the aperture ratio is 30%-40%.

[0030] Based on the embodiments described above, the cell depth of the gravure roller directly affects the amount of paste stored in a single cell, thus affecting the specific dimensions such as the thickness of the coated dot matrix. The aperture ratio, representing the ratio of the area of ​​the open area to the area of ​​the non-open area on the gravure roller, affects the ratio of the area covered by the coating layer to the area not covered on the substrate, thereby influencing the performance of the current collector. Therefore, by specifically limiting these two parameters—that is, by limiting them during the processing—the various performance characteristics of the processed current collector can be guaranteed.

[0031] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0032] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the current collector structure of the battery cell provided in the embodiment of this application.

[0033] Figure 2 This is a schematic flowchart of the battery cell current collector preparation method provided in the embodiments of this application.

[0034] Explanation of reference numerals in the attached figures 1. Base layer; 2. Coating layer; 21. Dot matrix coating block. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this application, it should be noted that, unless otherwise stated, the terms "inner," "outer," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" 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 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 according to the specific circumstances.

[0041] In the production and processing of power batteries, the core lies in the preparation of the battery cell. Specifically, structurally, a battery cell can be divided into a negative electrode and a positive electrode. Each electrode includes a current collector and active materials coated on the current collector. Taking the positive electrode as an example, the current collector is typically an aluminum foil structure, onto which active materials such as lithium iron phosphate are then coated.

[0042] However, the aforementioned positive electrode sheet will experience electrochemical corrosion and lithium plating issues during long-term use. During long-term cycling, side reactions in the electrolyte can cause localized corrosion of the aluminum foil, increasing the resistance of the current collector and leading to capacity decay in the battery cell. Simultaneously, lithium plating can also occur due to lithium ion deposition during long-term cycling and fast charging, affecting the battery cell's capacity.

[0043] In existing technologies, some solutions involve coating the current collector surface with a layer of graphene or other materials to improve its corrosion resistance. However, this can affect the peeling force of the positive electrode, thus affecting the coating and adhesion between the current collector and the active material, and consequently impacting the cell performance.

[0044] Therefore, there is an urgent need to provide a cell structure that can improve the problems of corrosion and lithium plating in the current collector, while increasing the peeling force of the electrode sheets, thereby improving the performance of the power battery.

[0045] To address the aforementioned problems in the prior art, embodiments of this application provide a cell current collector, as referenced. Figure 1As shown, the current collector of the battery cell includes a base layer 1 and a coating layer 2. The base layer 1 is configured as a metal foil. The coating layer 2 includes a plurality of lattice coating blocks 21, which are arrayed on the base layer 1, and the lattice coating blocks 21 include a high-porosity active component.

[0046] Based on the embodiments described above, a metal foil is used as the base layer 1 of the current collector. A coating layer 2 is then applied to the base layer 1, and this coating layer 2 contains highly porosity active components. The high porosity of the coating layer 2 creates a high-speed lithium-ion transport channel, allowing lithium ions to pass through quickly and improving lithium-ion deposition. This alleviates the problem of lithium plating on the current collector. Simultaneously, by applying the coating layer 2 to the surface of the base layer 1, direct contact between the base layer 1 and the electrolyte is reduced, thereby mitigating the electrochemical corrosion of the metal foil caused by side reactions in the electrolyte.

[0047] Furthermore, the coating layer 2 is specifically configured as a plurality of arrayed dot matrix coating blocks 21. By using a discontinuous coating method, the problems of reduced electrode peeling force and reduced electronic conductivity caused by traditional continuous coating are avoided. This not only improves the problems of lithium deposition and electrochemical corrosion of the current collector, but also enhances the peeling force of the electrode and ensures the electronic conductivity of the current collector.

[0048] In summary, this application utilizes the high porosity of the coating layer 2 on the substrate 1 to allow lithium ions to pass through quickly, thus improving issues such as lithium deposition in the current collector and the susceptibility to electrochemical corrosion. Furthermore, the coating layer 2 employs discontinuous dot matrix coating blocks 21, thereby enhancing the peeling force of the electrode, ensuring the electronic conductivity of the current collector, and ultimately improving the performance of both the current collector and the overall battery cell.

[0049] Specifically, the array-arranged dot-matrix coating blocks 21 in this application can not only improve the lithium ion throughput rate, reduce lithium deposition in the current collector, and improve the corrosion problem of the base layer 1 of the current collector, but also form an uneven structure on the surface of the current collector, so that the active material can better adhere to the current collector when it is coated on the current collector, thereby improving the peeling force of the electrode and making the adhesion between the active material and the current collector more stable and reliable, thereby improving the overall performance of the electrode.

[0050] Furthermore, taking the positive electrode current collector as an example, in practical applications, the metal foil can specifically be set as aluminum foil, utilizing the excellent conductivity of aluminum foil as the base layer 1 of the current collector. In addition, the technical solution of this application can also be applied to the negative electrode current collector. In this case, the specific material of the metal foil and the specific composition of the high-porosity active component can be adaptively adjusted according to different actual requirements; this application does not impose specific limitations in this regard. Simultaneously, the specific thickness of the metal foil can also be set with reference to existing technologies; this application does not impose specific limitations in this regard.

[0051] Furthermore, in practical use, the dot matrix coating block 21 can be set to any suitable shape, and in some embodiments, it can be further preferred to be a circular or regular polygonal structure, such as a square, a regular pentagon, or a regular hexagon. By specifically setting the dot matrix coating block 21 to a regular polygonal structure, the coverage area and coverage area of ​​the coating layer 2 in a unit area on the current collector can be better controlled, thereby making the properties of each area on the current collector more balanced, thus improving the performance of the current collector and the overall battery cell.

[0052] refer to Figure 1 As shown, in some embodiments of this application, the dot matrix coating block 21 is configured as a circular structure, and the diameter of the dot matrix coating block 21 is d, which can be specifically set to 50μm≤d≤200μm. The spacing between any two adjacent dot matrix coating blocks 21 is L, which can be specifically set to 100μm≤L≤500μm.

[0053] Based on the above embodiments of this application, the diameter and gap size of the dot matrix coating block 21 are limited. By limiting the area of ​​the area covered by the coating layer 2 and the area not covered by the coating layer 2 on the base layer 1, the ratio of the area covered by the coating layer 2 to the area not covered by the coating layer 2 is limited to a more suitable range. This balances the corrosion resistance, lithium plating resistance and conductivity of the current collector, so that the various properties of the current collector are kept within a more suitable and good range.

[0054] Specifically, in actual production and processing, a larger ratio of the area covered by the coating layer 2 to the area not covered by the coating layer 2 results in a faster lithium-ion throughput rate on the current collector and better corrosion resistance. However, this also reduces the overall electronic conductivity of the current collector. Therefore, it is necessary to control the area ratio within a suitable range. In specific settings, when the diameter of the dot matrix coating block 21 is large, the spacing between two adjacent dot matrix coating blocks 21 can be appropriately increased; conversely, when the diameter of the dot matrix coating block 21 is small, the spacing between two adjacent dot matrix coating blocks 21 can be appropriately reduced, so that the area covered by the coating layer 2 on the current collector is controlled within a suitable ratio range.

[0055] In practical use, the diameter of the dot matrix coating block 21 can be specifically set to multiple specific diameters such as 50μm, 80μm, 100μm, 150μm and 200μm, and the spacing between two adjacent dot matrix coating blocks 21 can also be specifically set to specific spacings such as 100μm, 150μm, 200μm, 300μm, 400μm and 500μm. This application does not impose specific limitations on this.

[0056] Furthermore, the above description, using a circular dot matrix coating block 21 as an example, illustrates the size of the dot matrix coating block 21 itself and the spacing between each dot matrix coating block 21. The same restrictions apply when the dot matrix coating block 21 is set to a square, regular pentagon, or regular hexagon. In this case, the restriction on the diameter of the dot matrix coating block 21 can be replaced by a restriction on the diameter of the circumcircle of the dot matrix coating block 21. The specific restriction can be adapted according to actual performance requirements, and this application does not impose specific limitations in this regard.

[0057] In some embodiments of this application, the thickness of the dot matrix coating block 21 is H, and the specific size of the thickness H of the dot matrix coating block 21 can be set to 0.5μm≤H≤2μm.

[0058] Based on the embodiments described above, by limiting the thickness of the dot matrix coating block 21, the specific thickness of the dot matrix coating block 21 is kept within a suitable range. When the thickness of the dot matrix coating block 21 is too thin, its ability to resist corrosion of the current collector and improve the lithium-ion throughput rate may be limited. Conversely, when the thickness of the dot matrix coating block 21 is too large, it will affect the overall thickness of the current collector, leading to an increase in the electrode thickness and consequently affecting the energy density of the battery. Furthermore, an excessively large thickness of the dot matrix coating block 21 may also result in material waste. Therefore, by limiting the thickness of the dot matrix coating block 21 to a suitable range, the aforementioned problems are mitigated.

[0059] Specifically, in practical applications, the specific thickness of the dot matrix coating block 21 can be set to multiple specific thicknesses such as 0.5μm, 1μm, 1.5μm and 2μm, and this application does not impose specific restrictions on this.

[0060] Furthermore, in practical applications, the specific components of the lattice coating block 21 are not limited to high-porosity active components. In some embodiments of this application, the lattice coating block 21 also includes a conductive reinforcing agent and an adhesive matrix. In the lattice coating block 21, the mass ratio of the high-porosity active component is 50%-60%, the mass ratio of the conductive reinforcing agent is 5%-12%, and the mass ratio of the adhesive matrix is ​​15%-40%.

[0061] Based on the embodiments described above, the coating layer 2 incorporates a high-porosity active component to increase the lithium-ion throughput rate, while a conductivity enhancer is used to improve the lateral conductivity of the coating layer 2. Furthermore, an adhesive matrix is ​​used to enhance the overall flexibility and adhesion of the coating layer 2, ensuring effective coating. Through the synergistic effect of these components, various properties of the coating layer 2 are achieved.

[0062] In the specific production and processing process, in some embodiments of this application, the high porosity active component can be set as nano-alumina particles, with a particle size range of 50nm-200nm.

[0063] Based on the above embodiments of this application, by specifically setting the high-porosity active component as nano-alumina particles, the oxygen-rich vacancies on the surface of the nano-alumina particles are used to form high-speed lithium-ion transport channels, enabling lithium ions to pass through quickly, thereby inhibiting lithium-ion deposition, improving the lithium plating situation in the current collector, and enhancing the performance of the current collector.

[0064] Meanwhile, this application selects nano-alumina particles as the high-porosity active component, mainly utilizing the high porosity characteristic of nano-alumina films. In actual production and processing, other high-porosity materials suitable for use inside the battery cell can also be selected as the high-porosity active component. The specific selection can be made according to the actual situation, and this application does not impose specific restrictions on this.

[0065] In some embodiments of this application, the conductivity enhancer may be at least one of graphene, carbon nanotubes, and carbon black.

[0066] Based on the embodiments described above, in practical applications, the conductivity enhancer can be any one of graphene, carbon nanotubes, and carbon black, or a mixture of these components can be used. The excellent conductivity of these materials is utilized to improve the overall lateral conductivity of the coating layer 2, thereby ensuring the overall conductivity of the current collector.

[0067] Specifically, in practical applications, graphene, carbon nanotubes, and carbon black can be used individually as conductivity enhancers, or they can be used in combination. For example, graphene, carbon nanotubes, and carbon black can be mixed together, or graphene can be mixed with carbon nanotubes, etc.

[0068] Furthermore, in this application, the term "lateral" for coating layer 2 refers to the direction extending along the surface of the base layer 1.

[0069] Similarly, in some embodiments of this application, the adhesive matrix may be polyacrylic acid.

[0070] Based on the above embodiments of this application, polyacrylic acid is used as the adhesive matrix. The strong adhesive force, chemical stability and electrolyte resistance of polyacrylic acid itself are utilized to enhance the overall adhesive force of the coating layer 2 and ensure the stable adhesion between the coating layer 2 and the base layer 1.

[0071] Furthermore, solid-state battery technology is also gradually developing in the existing technology. Under such circumstances, the technical solution of this application can also be adapted to improve the performance of solid-state batteries. Specifically, solid electrolyte lithium iron pentoxide (Li5FeO4) and other substances can be added to the composition of the above-mentioned coating layer 2. The specific mass ratio of lithium iron pentoxide is controlled at about 20%, and then the same dot matrix coating method is adopted. According to experimental results, when this technical solution is applied to solid-state batteries, it can reduce the interfacial impedance of the battery to 4.5Ω·cm² and the critical current density can reach 2.5mA / cm², which can effectively improve the performance of solid-state batteries. Specifically, the above technical solution of this application can be referred to and adapted according to the actual situation. This application does not impose specific limitations on it.

[0072] Based on the above technical solutions, this application embodiment also provides a battery, which includes an active material and the above-mentioned cell current collector, wherein the active material is coated on the cell current collector to form an electrode structure.

[0073] Based on the above embodiments of this application, the battery provided by this application includes the aforementioned cell current collector. Through the above configuration, by providing a coating layer 2 on the base layer 1, the high porosity of the coating layer 2 allows lithium ions to pass through quickly, improving problems such as lithium plating in the current collector and susceptibility to electrochemical corrosion. Simultaneously, the coating layer 2 employs discontinuous dot matrix coating blocks 21, thereby enhancing the peeling force of the electrode sheets, ensuring the electronic conductivity of the current collector, and thus improving the performance of the current collector and the overall cell, ultimately enhancing the aforementioned battery performance.

[0074] Furthermore, it should be noted that the components of the active substances in actual production and processing can be selected with reference to existing technologies, and this application does not impose specific restrictions in this regard.

[0075] Based on the above technical solutions, this application also provides a method for preparing a battery cell current collector, as described above. Figure 2 As shown, the method for preparing the current collector for a battery cell is applicable to the preparation of the aforementioned current collector for a battery cell. The method includes the following steps: S0010 slurry preparation involves mixing high-porosity active components, conductive reinforcing agents, and adhesive matrix in a specific ratio to form a coating slurry.

[0076] S0020 Gravure printing uses a gravure roller to transfer coating paste to the surface of a metal foil to form an array of dot-matrix coating blocks 21 on the metal foil.

[0077] S0030 is cured and molded, and the coated metal foil and the dot matrix coating block 21 are dried in three stages to form the current collector of the battery cell.

[0078] Based on the above embodiments of this application, the specific preparation method of the current collector of this application has been disclosed. A coating slurry is prepared according to the above proportions. The composition of the various components in the coating slurry is used to improve problems such as lithium plating and easy electrochemical corrosion in the current collector. Subsequently, gravure printing is used to complete the coating process, which not only simplifies and speeds up the coating process but also enables rapid array coating of the dot matrix coating blocks 21. The discontinuous dot matrix coating blocks 21 enhance the peel strength of the electrode, ensuring the electronic conductivity of the current collector. Finally, through drying and curing, the shape and adhesion position of the coating layer 2 are fixed, ultimately obtaining a current collector structure that is corrosion-resistant, lithium plating-resistant, and has high peel strength.

[0079] In some embodiments of this application, in the gravure printing step, the cell depth of the gravure roller is 30μm-50μm and the aperture ratio is 30%-40%.

[0080] Based on the embodiments described above, the cell depth of the gravure roller directly affects the amount of paste stored in a single cell on the gravure roller, thereby affecting the specific dimensions such as the thickness of the dot matrix coating block 21 formed by coating. The aperture ratio represents the ratio of the area of ​​the open area to the area of ​​the non-open area on the gravure roller, which in turn affects the ratio of the area covered by the coating layer 2 on the base layer 1 to the area not covered, thus affecting the performance of the current collector. Therefore, by specifically limiting the above two parameters, that is, by limiting them during the processing, the various performance characteristics of the processed current collector are guaranteed.

[0081] The performance of the current collector prepared by the current collector preparation method of this application will be further compared and illustrated below through a specific embodiment and two comparative examples.

[0082] Example 1 The method for preparing a current collector using the current collector provided in this application includes the following steps: For slurry preparation, nano-alumina particles, graphene, polyacrylic acid and water are mixed in a mass ratio of 6:1:2:2, and then ball-milled to disperse to a viscosity of 3000 cP to prepare a coating slurry.

[0083] Gravure printing is performed using a laser-engraved gravure roller. The depth of the gravure roller is set to 40μm, and the aperture ratio is set to 35%. The coating paste is rolled and transferred to the surface of the aluminum foil, which serves as the base layer 1, at a linear speed of 20 m / min. The thickness of the aluminum foil is set to 13μm.

[0084] The curing process involves a three-stage infrared drying process with drying temperatures of 80°C, 120°C, and 150°C, resulting in a coating layer 2 with a diameter of 100 μm for the dot matrix coating block 21, a spacing of 300 μm between adjacent dot matrix coating blocks 21, and a thickness of 1 μm.

[0085] Comparative Example 1 In the comparative example, no coating was applied to the base layer 1 of the current collector.

[0086] Comparative Example 2 Comparative Example 2 prepared a coating slurry using the same technical method as the slurry preparation steps in this scheme. The difference is that in Comparative Example 2, the slurry was continuously coated on the surface of the substrate 1 to cover the substrate 1 as a whole.

[0087] Table 1 below records the parameters of the current collectors prepared in Example 1, Comparative Example 1, and Comparative Example 2 when applied to batteries.

[0088]

[0089] As shown in Table 1, the current collector prepared by the current collector preparation method disclosed in this application in Example 1 has a better capacity retention rate and a greater electrode peeling force than the current collectors obtained in Comparative Example 1 and Comparative Example 2. It can also significantly reduce interface impedance and energy decay under fast charging.

[0090] The preferred embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0091] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0092] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.

Claims

1. A current collector for a battery cell, characterized in that, The current collector for the battery cell includes: The base layer is made of metal foil; The coating layer includes a plurality of lattice coating blocks, the array of which is coated on the substrate, and the lattice coating blocks include a high-porosity active component.

2. The current collector for the battery cell according to claim 1, characterized in that, The dot matrix coating block is configured as a circular structure, and the diameter of the dot matrix coating block is d, 50μm≤d≤200μm; The spacing between any two adjacent dot matrix coating blocks is L, where 100μm≤L≤500μm.

3. The current collector for the battery cell according to claim 1, characterized in that, The thickness of the dot matrix coating block is H, where 0.5μm≤H≤2μm.

4. The current collector for the battery cell according to any one of claims 1-3, characterized in that, The lattice coating block further includes a conductive reinforcing agent and an adhesive matrix. In the lattice coating block, the mass ratio of the high porosity active component is 50%-60%, the mass ratio of the conductive reinforcing agent is 5%-12%, and the mass ratio of the adhesive matrix is ​​15%-40%.

5. The current collector for the battery cell according to claim 4, characterized in that, The high-porosity active component is nano-alumina particles, and the particle size range of the nano-alumina particles is 50nm-200nm.

6. The current collector for the battery cell according to claim 4, characterized in that, The conductive enhancer is selected from at least one of graphene, carbon nanotubes, and carbon black.

7. The current collector for the battery cell according to claim 4, characterized in that, The adhesive matrix is ​​set as polyacrylic acid.

8. A battery, characterized in that, The battery includes: Active substances; and, According to any one of claims 1-7, the active material is coated on the current collector to form an electrode structure.

9. A method for preparing a current collector for a battery cell, applicable to the preparation of a current collector for a battery cell as described in any one of claims 1-7, characterized in that, The method for preparing the current collector for the battery cell includes the following steps: Slurry preparation involves mixing high-porosity active components, conductive reinforcing agents, and adhesive matrix in a specific ratio to prepare a coating slurry. Gravure printing uses a gravure roller to transfer coating paste onto the surface of a metal foil to form an array of dot-matrix coated blocks on the metal foil. The coated metal foil and the dot matrix coating block are dried together in three stages to form the current collector of the battery cell.

10. The method for preparing a current collector for a battery cell according to claim 9, characterized in that, In the gravure printing step, the cell depth of the gravure roller is 30μm-50μm, and the aperture ratio is 30%-40%.

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