Composite current collector and preparation method thereof, battery and electric equipment

Abstract

The invention discloses a composite current collector and a preparation method thereof, a battery and electric equipment. The composite current collector comprises an insulating layer and a metal layer. At least one side of the insulating layer in the thickness direction is provided with a metal layer. Wherein a through hole is formed in the composite current collector, a carbon layer is arranged on the surface of one side, far away from the insulating layer, of the metal layer and in the through hole, and a first anchoring layer is formed between the carbon layer and the metal layer. According to the composite current collector disclosed by the invention, the arrangement of the carbon layer and the arrangement of the first anchoring layer are beneficial to increasing the passing area of electron conductance, improving the conductive efficiency of the composite current collector and improving the structural stability of the composite current collector. The carbon layer can enhance the binding force between the composite current collector and the active material layer by filling the surface defects of the metal layer, and the flexibility and the structural strength of the composite current collector are improved. And the carbon layers in the through holes are beneficial to realizing communication of electrons on two sides of the thickness of the composite current collector, so that the impedance of the composite current collector is reduced, and the electron conductance is enhanced.

Description

Technical Field

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

[0002] The current collector is a crucial component in electrochemical devices such as batteries, collecting and conducting current. Inside the battery, the electrode active materials undergo redox reactions, generating or consuming electrons. The current collector collects these electrons, forming a current path that allows the battery to output or receive current, ensuring stable charge and discharge operations. The current collector also provides physical support for the electrode active materials, ensuring they are evenly distributed across their surface, maintaining good contact and stability.

[0003] The composite current collector is primarily constructed by depositing copper or aluminum metal on both sides of an insulating film through vapor deposition. In related technologies, the two sides of the composite current collector are not conductive, resulting in a small flow area and relatively high physical impedance. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first object of the present invention is to provide a composite current collector that increases the passage area for electron conduction, improves the conductive efficiency of the composite current collector, enhances the structural stability of the composite current collector, reduces the impedance of the composite current collector, and enhances the electron conduction.

[0005] The second object of the present invention is to provide a method for preparing a composite current collector.

[0006] The third object of the present invention is to provide a battery.

[0007] A fourth object of the present invention is to provide an electrical device.

[0008] According to an embodiment of the first aspect of the present invention, a composite current collector includes: an insulating layer; a metal layer, wherein the metal layer is provided on at least one side of the insulating layer in a thickness direction; wherein a through hole is formed on the composite current collector, a carbon layer is provided on a surface of the metal layer away from the insulating layer and in the through hole, and a first anchoring layer is formed between the carbon layer and the metal layer.

[0009] According to the composite current collector of the embodiment of the present invention, the provision of the carbon layer and the provision of the first anchoring layer help to increase the passage area of ​​electronic conduction, improve the conductive efficiency of the composite current collector, and improve the structural stability of the composite current collector. By providing the carbon layer on the side of the metal layer away from the insulating layer and in the through-hole, the carbon layer can fill the surface defects of the metal layer to enhance the bonding force between the composite current collector and the active material layer, thereby improving the flexibility and structural strength of the composite current collector. The carbon layer in the through-hole helps to achieve the connection of electrons on both sides of the thickness of the composite current collector, reduce the impedance of the composite current collector, and enhance electronic conduction.

[0010] According to some embodiments of the present invention, the thickness of the first anchoring layer accounts for 5% to 20% of the thickness of the carbon layer.

[0011] According to some embodiments of the present invention, a second anchor layer is formed between the carbon layer and the insulating layer.

[0012] According to some embodiments of the present invention, the thickness of the second anchoring layer accounts for 8% to 50% of the thickness of the carbon layer.

[0013] According to some embodiments of the present invention, the through hole has a diameter of 5 μm to 100 μm.

[0014] According to some embodiments of the present invention, there are a plurality of through holes, and the porosity of the surface of the composite current collector is 0.002% to 20%.

[0015] According to some embodiments of the present invention, the thickness of the metal layer is 0.1 μm to 3 μm; and / or the thickness of the insulating layer is 5 μm to 20 μm.

[0016] According to some embodiments of the present invention, the carbon layer, the first anchoring layer, and the second anchoring layer have the same composition, including at least one of graphene and few-layer graphite.

[0017] The method for preparing a composite current collector according to the second embodiment of the present invention comprises the following steps: Punching treatment: punching holes in the pre-composite current collector formed by the insulating layer and the metal layer to form through holes; Ion implantation treatment: a carbon layer, a first anchoring layer, and a second anchoring layer are provided on the pre-composite current collector by using an ion implantation technique to prepare the composite current collector.

[0018] According to some embodiments of the present invention, the amount of ions implanted is 1×10 11 ion / cm 2 ~1×10 18 ion / cm 2; and / or, the injection time of the ion implantation treatment is 0.5 min to 20 min; and / or, the injection energy of the ion implantation treatment is 1 keV to 30 keV.

[0019] According to some embodiments of the present invention, the pre-composite current collector after the punching process is pre-treated before the ion implantation process. The pre-treatment includes: cleaning the pre-composite current collector, acid washing, and drying.

[0020] The battery according to the third embodiment of the present invention includes at least one composite current collector according to the first embodiment of the present invention, or includes at least one preparation method of the composite current collector according to the second embodiment of the present invention.

[0021] An electrical device according to an embodiment of a fourth aspect of the present invention comprises at least one battery according to an embodiment of the third aspect of the present invention.

[0022] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which: Figure 1 is a cross-sectional view of a composite current collector according to an embodiment of the present invention; Figure 2 is a cross-sectional view of a composite current collector according to another embodiment of the present invention; Figure 3 is a schematic diagram of a composite current collector according to an embodiment of the present invention.

[0024] Reference numerals: 100: composite current collector; 1: Insulation layer; 2: Metal layer; 3: Through hole; 4: Carbon layer. DETAILED DESCRIPTION

[0025] Reference below Figure 1-Figure 3 A composite current collector 100 according to an embodiment of the present invention is described.

[0026] like Figure 1-Figure 3 As shown, the composite current collector 100 according to an embodiment of the present invention includes an insulating layer 1 and a metal layer 2 .

[0027] Specifically, a metal layer 2 is provided on at least one side of the insulating layer 1 in the thickness direction. A through hole 3 is formed on the composite current collector 100. A carbon layer 4 is provided on the surface of the metal layer 2 away from the insulating layer 1 and within the through hole 3. A first anchor layer is formed between the carbon layer 4 and the metal layer 2.

[0028] For example, in Figure 1 and Figure 2 In the example, the metal layer 2 can be provided only on one side of the insulating layer 1 in the thickness direction; or, the metal layer 2 can be provided on both sides of the insulating layer 1 in the thickness direction. The insulating layer 1 can be used to prevent short circuits between the composite current collector 100 and other components, reduce the probability of internal short circuits of the positive electrode active material and / or the negative electrode active material to a certain extent, ensure that the current inside the battery flows according to the designed path, and improve the safety and stability of the battery. The insulating layer 1 can provide a certain amount of mechanical support, enhance the corrosion resistance and tensile strength of the structure of the overall composite insulator, and reduce the shedding of active materials. At the same time, the insulating layer 1 can isolate the metal layer 2 from direct contact with substances such as the electrolyte, prevent the metal layer 2 from being corroded, extend the service life of the composite current collector 100, and also prevent the dissolution of metal ions from adversely affecting the battery performance. In addition, by adjusting the surface properties of the insulating layer 1, the interfacial bonding force between the composite current collector 100 and the active material can be improved, so that the active material can be better attached to the composite current collector 100, thereby improving the overall performance of the battery.

[0029] Metal layer 2 serves as the primary current transmission channel, collecting and outputting the current generated by the active materials. This ensures efficient electron transfer within the battery and provides an electron channel for electrochemical reactions during the charge and discharge process, accelerating charge transfer. Furthermore, metal layer 2 provides a carrier for the battery's positive and / or negative active materials to adhere to, allowing the active materials to be evenly distributed across the surface of the composite current collector 100, ensuring the smooth conduction of electrochemical reactions.

[0030] The metal layer 2 may be a copper layer (Cu), and the insulating layer 1 may be a polyethylene terephthalate layer (PET), which are not specifically limited here.

[0031] A carbon layer 4 is disposed on the surface of the metal layer 2 facing away from the insulating layer 1 and within the through-hole 3. The addition of the carbon layer 4 improves the electronic conductivity between the metal layer 2 and the active material layer, reducing impedance. Furthermore, the carbon layer 4 fills surface defects in the metal layer 2, thereby enhancing the bonding between the composite current collector 100 and the active material layer and improving the flexibility and structural strength of the composite current collector 100. The carbon layer 4 within the through-hole 3 facilitates electron communication across the thickness of the composite current collector 100, reducing impedance and enhancing electronic conductivity.

[0032] The first anchoring layer is a cross-linking layer formed on the surface of the metal layer 2. Metals have high surface energy and a large number of active sites on the surface. These active sites can interact with the first anchoring layer. For example, metal atoms can form chemical bonds with atoms in the first anchoring layer. Thus, the first anchoring layer is used to connect the carbon layer 4 and the metal layer 2, thereby increasing the integrity of the composite current collector 100, improving the structural stability of the composite current collector 100, and at the same time increasing the passage area of ​​electronic conduction, thereby improving the conductive efficiency of the composite current collector 100.

[0033] According to the composite current collector 100 of the embodiment of the present invention, the provision of the carbon layer 4 and the provision of the first anchor layer help increase the passage area of ​​electronic conduction, improve the conductive efficiency of the composite current collector 100, and improve the structural stability of the composite current collector 100. By providing the carbon layer 4 on the side of the metal layer 2 away from the insulating layer 1 and within the through hole 3, the carbon layer 4 can fill the surface defects of the metal layer 2 to enhance the bonding force between the composite current collector 100 and the active material layer, thereby improving the flexibility and structural strength of the composite current collector 100. The carbon layer 4 within the through hole 3 helps to achieve the connection of electrons on both sides of the thickness of the composite current collector 100, reduce the impedance of the composite current collector 100, and enhance electronic conduction.

[0034] According to some embodiments of the present invention, referring to Figure 1 and Figure 2 The thickness of the first anchoring layer accounts for 5% to 20% of the thickness of the carbon layer 4. Therefore, the thickness of the first anchoring layer is relatively reasonable, avoiding the first anchoring layer being too thick and causing the connection with the metal layer 2 and the carbon layer 4 to be reduced under the action of gravity, and fully ensuring the reliability of the connection between the first anchoring layer and the metal layer 2 and the carbon layer 4.

[0035] According to some embodiments of the present invention, a second anchoring layer is formed between the carbon layer 4 and the insulating layer 1. The second anchoring layer is a cross-linked layer formed on the surface of the insulating layer 1, which is typically composed of covalently bonded polymer materials or ceramic materials. The second anchoring layer interacts with the surface of the insulating layer 1 to achieve a connection between the second anchoring layer and the insulating layer 1. At the same time, the second anchoring layer is connected to the carbon layer 4, which helps to further improve the integrity and structural stability of the composite current collector 100, while also increasing the passage area of ​​electronic conduction, thereby ensuring the conductive performance of the composite current collector 100.

[0036] Furthermore, the thickness of the second anchoring layer accounts for 8% to 50% of the thickness of the carbon layer 4. The thickness of the second anchoring layer is relatively reasonable, which increases the connection area between the second anchoring layer, the insulating layer 1, and the carbon layer 4, thereby helping to fully utilize the function of the second anchoring layer, so that the second anchoring layer can stably and reliably connect the carbon layer 4 and the insulating layer 1.

[0037] According to some embodiments of the present invention, the aperture of the through hole 3 is 5 μm to 100 μm. For example, the aperture of the through hole 3 can be 5 μm, 10 μm, 20 μm, 45 μm, 65 μm, 85 μm or 100 μm. If the aperture of the through hole 3 is too large, it will easily lead to a decrease in the mechanical strength of the composite current collector 100; if the aperture of the through hole 3 is too small, it will affect the penetration of the electrolyte and the efficiency of ion transmission. Therefore, the aperture of the through hole 3 is relatively reasonable, which is conducive to the formation of the carbon layer 4 in the through hole 3 to achieve electronic conductivity, so that the electrolyte can more fully penetrate between the composite current collector 100 and the active material, providing more channels for the transmission of ions during the charge and discharge process, thereby accelerating the migration speed of ions and improving the charge and discharge performance of the battery. At the same time, the presence of the through hole 3 can also change the local current density on the inner and outer surfaces of the composite current collector 100, making the charge distribution more uniform. In addition, the active material can be embedded in the through hole 3, so that the contact between the active material and the composite current collector 100 is closer and the bonding force is stronger. During the battery charge and discharge cycle, the shedding of the active material can be reduced, thereby improving the stability and service life of the battery.

[0038] According to some embodiments of the present invention, referring to Figure 1 and Figure 2 , there are multiple through holes 3, and the porosity of the surface of the composite current collector 100 is 0.002% to 20%. In the description of the present invention, "multiple" means two or more. Among them, if the porosity is too low, it is difficult to fully play the role of the through hole 3, and it is easy to have problems such as poor ion transmission and limited active material loading; if the porosity is too high, the mechanical strength and conductive performance of the composite current collector 100 will be reduced, affecting the overall performance of the battery. Therefore, the porosity of the surface of the above-mentioned composite current collector 100 is relatively reasonable, which is conducive to fully playing the role of the through hole 3, accelerating the migration speed of ions, improving the charge and discharge performance of the battery, and at the same time ensuring the structural strength of the composite current collector 100 and extending the service life of the composite current collector 100.

[0039] According to some embodiments of the present invention, the thickness of the metal layer 2 is 0.1 μm to 3 μm. For example, the thickness of the metal layer 2 can be 0.1 μm, 0.5 μm, 1 μm, 2 μm or 3 μm. The thickness of the metal layer 2 is relatively reasonable, which helps to ensure a reasonable resistance of the composite current collector 100, so that the battery has a high charge and discharge efficiency and can output a large current and power, thereby helping to improve the conductivity of the composite current collector 100. At the same time, it avoids the thicker metal layer 2 from increasing the mass of the composite current collector 100. When the overall volume and mass of the battery are constant, the proportion of active materials is relatively reasonable, which is conducive to ensuring the energy density of the battery. In addition, the thickness of the metal layer 2 is relatively reasonable, which helps to improve the mechanical strength of the composite current collector 100, making the composite current collector 100 less likely to deform or break during battery assembly and use, and reducing safety hazards such as internal short circuits in the battery caused by damage to the composite current collector 100.

[0040] The thickness of the insulating layer 1 is 5 μm to 20 μm. The thickness of the insulating layer 1 is relatively reasonable, which can effectively prevent leakage and short circuit between the composite current collector 100 and other components, improve the insulation performance and stability of the battery, ensure that the current flows according to the designed path during the charge and discharge process of the battery, and avoid excessively thick insulating layer 1 from hindering the ion transport in the electrolyte, thereby reducing the resistance to ion migration, improving the charge and discharge performance of the battery, and extending the cycle life of the battery. At the same time, the insulating layer 1 of the above thickness can effectively isolate the composite current collector 100 from adjacent electrodes or other conductive components, reduce the risk of short circuit and thermal runaway, and improve the safety of the battery. In addition, the insulating layer 1 also has a heat insulation effect to a certain extent. The insulating layer 1 of the above thickness can help the battery better dissipate heat during the charge and discharge process, improve the thermal stability of the battery, and prevent battery performance degradation or safety problems caused by local overheating.

[0041] Furthermore, the carbon layer 4, the first anchoring layer, and the second anchoring layer have the same composition, including at least one of graphene and few-layer graphite. This consistency in composition helps reduce the difficulty and improve the efficiency of preparing the composite current collector 100.

[0042] Graphene is a two-dimensional carbon material with excellent electrical, mechanical, and thermal properties. Graphene can improve the conductivity of the composite current collector 100 and the utilization rate of active materials in the electrode, contributing to improved overall battery performance. Few-layer graphite generally refers to a graphite material composed of a few layers (usually 2-10) of stacked carbon atoms. The carbon atoms in each layer are covalently linked to form a hexagonal planar network structure, and the layers interact with each other through weak van der Waals forces. Few-layer graphite has a certain degree of flexibility and mechanical strength, and is more stable. When subjected to external forces, the layers may slide relative to each other, but the overall structure is not easily damaged. Few-layer graphite also has good thermal conductivity.

[0043] Therefore, using at least one of graphene and few-layer graphite as the carbon layer 4, the first anchor layer and the second anchor layer helps to meet the conductivity requirements of the composite current collector 100. At the same time, the cost of the above materials is relatively low, which is conducive to controlling the preparation cost of the composite current collector 100.

[0044] The method for preparing the composite current collector 100 according to the second embodiment of the present invention comprises the following steps: Punching: Punching a hole 3 on the pre-composite current collector formed by the insulating layer 1 and the metal layer 2. The punching method can be mechanical punching or laser punching.

[0045] Ion implantation treatment: A carbon layer 4, a first anchoring layer and a second anchoring layer are arranged on the pre-composite current collector using ion implantation technology to prepare a composite current collector 100. Ion implantation is a technology that injects an ion beam with a certain energy into the surface of a solid material. During the ion implantation process, the atoms or molecules to be implanted must first be ionized into ions, and then the ion beam is drawn out through an ion source, and then the ion beam is accelerated to the required energy using an accelerator so that it has sufficient kinetic energy. These high-energy ions are shot toward the surface of the target material at an extremely high speed under the action of an electric field. When the ions collide with the atoms on the surface of the material, part of the energy will be transferred to the atoms of the material, causing the atoms of the material to shift, lattice distortion, etc., while the ions gradually slow down and eventually stay inside the material, thereby changing the physical, chemical and electrical properties of the surface of the material.

[0046] Thus, through ion implantation, a carbon layer 4 is coated on the surface of the composite current collector 100 and in the through-holes 3, forming a first anchoring layer between the metal layer 2 and the carbon layer 4, and a second anchoring layer between the insulating layer 1 and the carbon layer 4. Since metal bonding energy is higher and ion implantation is more difficult, the thickness of the first anchoring layer is relatively small. However, ion implantation into the insulating layer 1 is relatively simple, so the thickness of the second anchoring layer is relatively large.

[0047] Furthermore, the amount of ions implanted is 1×10 11 ion / cm2 ~1×10 18 ion / cm 2 ; and / or, the injection time of the ion implantation process is 0.5 min to 20 min; and / or, the injection energy of the ion implantation process is 1 keV to 30 keV. The ion dose refers to the total number of ions implanted into the target material per unit area. The injection time is related to the amount of ions implanted and the beam current density. Under a constant beam current density, the greater the implantation dose, the longer the required injection time. The injection energy refers to the energy possessed by the ions during the implantation process, which determines the movement speed and penetration ability of the ions. The injection energy directly determines the ion implantation depth. The higher the energy, the deeper the ions penetrate into the target material.

[0048] The above-mentioned ion implantation ion amount, implantation time and implantation energy are reasonably limited, so that the strength and thickness of the carbon layer 4, the first anchoring layer and the second anchoring layer formed by ion implantation are suitable for meeting the needs of the composite current collector 100, which is beneficial to ensure the stability and reliability of the arrangement of the carbon layer 4 on the side of the metal layer 2 away from the insulating layer 1 and in the through hole 3, the stability and reliability of the first anchoring layer connecting the metal layer 2 and the carbon layer 4, and the stability and reliability of the second anchoring layer connecting the insulating layer 1 and the carbon layer 4.

[0049] According to some embodiments of the present invention, the punched pre-composite current collector is pre-treated before ion implantation. The pre-treatment includes cleaning the pre-composite current collector, acid washing, and drying. Specifically, after removing dirt from the composite current collector 100, the metal surface is roughened by acid washing, followed by drying. This helps improve the efficiency of subsequent ion implantation.

[0050] The battery according to the third embodiment of the present invention includes at least one composite current collector 100 according to the first embodiment of the present invention, or includes at least one preparation method of the composite current collector 100 according to the second embodiment of the present invention.

[0051] The battery according to the embodiment of the present invention uses the composite current collector 100, which helps to improve the conductive stability of the battery, reduce energy loss, improve charge and discharge efficiency, and at the same time increase the battery density and enhance the market competitiveness of the battery.

[0052] An electrical device according to an embodiment of a fourth aspect of the present invention comprises at least one battery according to an embodiment of the third aspect of the present invention.

[0053] According to the electric device of the embodiment of the present invention, the use of the above-mentioned battery is conducive to improving the use stability of the electric device, increasing the cruising range or use time of the electric device, and thus helping to improve the user experience of the electric device.

[0054] The following embodiments of the present invention are described in detail. It should be noted that the following embodiments are illustrative and are intended only to explain the present invention and are not to be construed as limiting the present invention. In addition, unless otherwise expressly stated, all reagents used in the following embodiments are commercially available or can be synthesized according to methods described herein or known methods. Reaction conditions not listed are also readily available to those skilled in the art.

[0055] Battery cell preparation method: Composite copper foil and composite aluminum foil with a carbon layer 4 are prepared using the above-described preparation method. Subsequently, the positive electrode active material layer is coated on both sides of the composite aluminum foil, and the negative electrode active material layer slurry is coated on both sides of the composite copper foil. After drying, rolling, and cutting, the positive and negative electrode sheets are respectively produced. The positive electrode sheet, separator, and negative electrode sheet are then stacked or wound according to conventional battery cell assembly procedures to form a core. This core is then sealed in a sealed housing, filled with electrolyte, and sealed to produce a battery cell.

[0056] Example 1 8μm thick composite copper foil (1μmCu+6μmPET+1μmCu) and 15μm thick composite aluminum foil (2μmAl+9μmPET+2μmAl) were mechanically punched to produce pre-composite current collectors with a pore diameter of 5μm and a porosity of 5%. After decontamination, acid washing, and drying, the pre-composite current collectors were placed in an ion implantation instrument and ions were implanted into the composite copper foil and composite aluminum foil, with an implantation volume of 1×10 14 ion / cm 2 The injection time was 13 minutes, and the injection energy was 10 keV. After cleaning and drying, the corresponding composite current collector 100 (composite copper foil) and composite current collector 100 (composite aluminum foil) were obtained. The composite copper foil and aluminum foil produced in this embodiment were designed based on the positive and negative active materials of power-type battery cells and manufactured according to the general method described above into a power-type battery cell with a nominal capacity of 32 Ah.

[0057] Example 2 A 6.5 μm thick composite copper foil (1 μm Cu + 4.5 μm PET + 1 μm Cu) and a 10 μm thick composite aluminum foil (2 μm Al + 6 μm PET + 2 μm Al) were mechanically punched to create a composite current collector 100 with a through-hole structure of 10 μm in diameter and a porosity of 10%. After decontamination and drying, the composite copper foil and composite aluminum foil were placed in an ion implantation instrument and ion implanted with a carbon layer 4, with an implantation rate of 1×10 16 ion / cm 2The injection time was 14 minutes and the injection energy was 12 keV. After cleaning and drying, the corresponding carbon-coated composite copper foil and composite aluminum foil were obtained. The composite copper foil and aluminum foil produced in this embodiment were designed based on the positive and negative active materials of energy-type battery cells and manufactured according to the general method described above into energy-type battery cells with a nominal capacity of 100 Ah.

[0058] Example 3 A 6.5μm thick composite copper foil (1μmCu+4.5μmPET+1μmCu) and a 10μm thick composite aluminum foil (2μmAl+6μmPET+2μmAl) were mechanically punched to create a composite current collector 100 with a through-hole structure of 10μm diameter and 10% porosity. After decontamination and drying, the composite copper foil and composite aluminum foil were placed in an ion implantation instrument and ion implanted with a carbon layer 4, with an implantation rate of 3×10 15 ion / cm 2 The injection time was 13 minutes and the injection energy was 10 keV. After cleaning and drying, the corresponding carbon-coated composite copper foil and composite aluminum foil were obtained. The composite copper foil and aluminum foil produced in this embodiment were designed based on the positive and negative active materials of energy-type battery cells and manufactured according to the general method described above into energy-type battery cells with a nominal capacity of 100 Ah.

[0059] Example 4 The preparation method of the composite current collector of this embodiment is similar to that of embodiment 2, except that ion implantation is performed, wherein the implantation amount is 5×10 15 ion / cm 2 , the injection time is 15 min, and the injection energy is 16 keV.

[0060] Example 5 The preparation method of the composite current collector of this embodiment is similar to that of embodiment 2, except that ion implantation is performed, wherein the implantation amount is 1×10 16 ion / cm 2 The injection time is 17 min and the injection energy is 20 keV.

[0061] Example 6 The preparation method of the composite current collector of this embodiment is similar to that of embodiment 2, except that ion implantation is performed, wherein the implantation amount is 1×10 18 ion / cm 2 The injection time is 19 min and the injection energy is 28 keV.

[0062] Example 7 The preparation method of the composite current collector of this embodiment is similar to that of embodiment 2, except that ion implantation is performed, wherein the implantation amount is 5×10 11 ion / cm2 , the injection time is 5 min, and the injection energy is 5 keV.

[0063] Example 8 The preparation method of the composite current collector of this embodiment is similar to that of embodiment 2, except that ion implantation is performed, wherein the implantation amount is 5×10 19 ion / cm 2 , the injection time is 21 min, and the injection energy is 30 keV.

[0064] Example 9 The preparation method of the composite current collector of this embodiment is similar to that of embodiment 2, except that ion implantation is performed, wherein the implantation amount is 5×10 10 ion / cm 2 , the injection time is 2 min, and the injection energy is 3 keV.

[0065] Example 10 The preparation method of the composite current collector of this embodiment is substantially the same as that of embodiment 2, except that the composite current collector 100 having a through-hole structure with a hole diameter of 50 μm and a porosity of 0.002% is punched out by mechanical punching.

[0066] Example 11 The preparation method of the composite current collector of this embodiment is substantially the same as that of embodiment 2, except that the composite current collector 100 having a through-hole structure with a hole diameter of 5 μm and a porosity of 20% is punched out by mechanical punching.

[0067] Example 12 The preparation method of the composite current collector of this embodiment is substantially the same as that of embodiment 2, except that the composite current collector 100 having a through-hole structure with a hole diameter of 100 μm and a porosity of 0.002% is punched out by mechanical punching.

[0068] Comparative Example 1 An 8μm thick composite copper foil (1μmCu+6μmPET+1μmCu) and a 15μm thick composite aluminum foil (2μmAl+9μmPET+2μmAl) were coated with a carbon layer 4 (the thickness of the carbon layer 4 was 0.2μm) by conventional wet method, and then assembled into a 32Ah power cell according to normal battery assembly.

[0069] Comparative Example 2 A 6.5μm-thick composite copper foil (1μmCu + 4.5μmPET + 1μmCu) and a 10μm-thick composite aluminum foil (2μmAl + 6μmPET + 2μmAl) were mechanically punched to create composite current collectors 100 with 10μm diameter pores and a porosity of 10%. After conventional wet coating with a 0.3μm-thick carbon layer 4, the cells were assembled as per standard battery procedures to create a 100Ah energy cell.

[0070] Performance Testing (1) Impedance test: Perform a 1.5C pulse discharge test for 10 seconds at 25°C and 25% SOC, and record the voltage V0 before and after the test. Under this condition, the battery impedance DCIR is (V0-V1) / (1.5×cell capacity).

[0071] (2) Cycle life test: The battery was charged at 1C to a voltage of 3.8V at 45°C, left for 30 minutes, and then discharged at a discharge rate of 1C to a voltage of 2.0V. This cycle was repeated 500 times, and the capacity retention rate was recorded. Capacity retention rate after 500 cycles (%) = discharge specific capacity after 500 cycles / discharge specific capacity after the third cycle × 100%.

[0072] Table 1 Performance test data of Examples 1-12 and Comparative Examples 1-2

[0073] Result Analysis Compared to Comparative Examples 1 and 2, Examples 1-12 all employed ion implantation to form a carbon layer 4 on the surface of the metal layer 2 distal from the insulating layer 1 and within the through-hole 3. Furthermore, a first anchoring layer was formed between the metal layer 2 and the carbon layer 4, and a second anchoring layer was formed between the insulating layer 1 and the carbon layer 4. Performance testing results showed that the impedance of Examples 1-12 was reduced. The rational placement of the carbon layer 4 helped reduce the impedance of the composite current collector 100 and enhance electronic conductivity. Furthermore, a comparison of Examples 2-9 revealed that the thickness of the ion-implanted carbon layer also had an optimal range (i.e., the first anchoring layer accounted for 5% to 20% of the carbon layer thickness, and the second anchoring layer accounted for 8% to 50% of the carbon layer thickness). As the amount of implanted carbon increased, excessively thick carbon layers could affect the magnitude of the impedance reduction. A comparison of Examples 2 and 10-12 revealed that the through-hole diameter and porosity also significantly impacted the impedance and cycle life of the composite current collector 100.

[0074] In the description of the present invention, it should be understood that the terms "center", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0075] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0076] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0077] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A composite current collector, characterized in that: include: Insulation layer; a metal layer, the metal layer being provided on at least one side in a thickness direction of the insulating layer; A through hole is formed on the composite current collector, a carbon layer is provided on a surface of the metal layer away from the insulating layer and in the through hole, and a first anchor layer is formed between the carbon layer and the metal layer.

2. The composite current collector according to claim 1, characterized in that The thickness of the first anchoring layer accounts for 5% to 20% of the thickness of the carbon layer.

3. The composite current collector according to claim 1, wherein: A second anchor layer is formed between the carbon layer and the insulating layer.

4. The composite current collector according to claim 3, characterized in that The thickness of the second anchoring layer accounts for 8% to 50% of the thickness of the carbon layer.

5. The composite current collector according to claim 1, characterized in that The through hole has a diameter of 5 μm to 100 μm.

6. The composite current collector according to any one of claims 1 to 5, characterized in that: There are a plurality of through holes, and the porosity of the surface of the composite current collector is 0.002% to 20%.

7. The composite current collector according to any one of claims 1 to 5, characterized in that: The thickness of the metal layer is 0.1 μm to 3 μm; and / or, The thickness of the insulating layer is 5 μm to 20 μm.

8. The composite current collector according to any one of claims 3, characterized in that: The carbon layer, the first anchoring layer, and the second anchoring layer have the same composition, including at least one of graphene and few-layer graphite.

9. A method for preparing a composite current collector according to any one of claims 1 to 8, characterized in that: The steps include: Punching treatment: punching holes in the pre-composite current collector formed by the insulating layer and the metal layer to form through holes; Ion implantation treatment: a carbon layer, a first anchoring layer, and a second anchoring layer are provided on the pre-composite current collector by using an ion implantation technique to prepare the composite current collector.

10. The preparation method according to claim 9, characterized in that The amount of ions implanted is 1×10 11 ion / cm 2 ~1×10 18 ion / cm 2 and / or, The ion implantation time is 0.5 min to 20 min; and / or, The implantation energy of the ion implantation process is 1 keV to 30 keV.

11. The preparation method according to claim 9, characterized in that Before the ion implantation process, the method further includes pre-treating the pre-composite current collector after the punching process. The pretreatment includes: cleaning the pre-composite current collector, acid washing and drying.

12. A battery, characterized in that: A method for preparing a composite current collector comprising at least one composite current collector according to any one of claims 1 to 8, or comprising at least one composite current collector according to any one of claims 9 to 11.

13. An electrical device, characterized in that: Comprising at least one battery according to claim 12.

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