A composite copper foil conductive layer structure

Abstract

This utility model relates to a composite copper foil conductive layer structure, comprising a substrate layer, a transition layer, and a conductive layer. The conductive layer is located on the surface of the substrate layer, and the transition layer is located between the substrate layer and the conductive layer. Micropores are formed on the surface of the substrate layer by plasma etching. The transition layer is formed on the surface of the substrate layer by magnetron sputtering. Cross-linked mesh grooves are formed on the surface of the conductive layer by laser engraving or chemical etching. This structure, through a multi-layer composite design, provides mechanical support through the substrate layer, enhances interfacial bonding through the transition layer, and optimizes conductivity through the conductive layer. By combining a lightweight substrate with a highly conductive metal layer, a balance between high strength, high flexibility, and excellent electrical performance is achieved.

Description

Technical Field

[0001] This utility model belongs to the field of composite copper foil technology, specifically relating to a composite copper foil conductive layer structure. Background Technology

[0002] Traditional electrolytic copper foil has significant limitations as a current collector for lithium-ion batteries: resource dependence: 80% of the world's copper resources are concentrated in a few countries such as Chile, and the copper price exceeded 80,000 yuan / ton in 2023, resulting in the cost accounting for more than 60% of the total cost of anode materials; technical bottlenecks: copper foil thinner than 6μm is prone to breakage during processing, with a mass production yield of less than 70%, and there is a risk of puncture; performance ceiling: after reducing the thickness of existing copper foil to 4.5μm, the mass energy density is increased by less than 5%, while composite copper foil can improve it by more than 7% through the "metal-polymer-metal" sandwich structure.

[0003] After CATL first proposed the concept of composite current collectors in 2018, two major camps emerged in the technology route: the two-step method (magnetron sputtering + electroplating): led by Guanghe Technology, which broke through the vacuum coating technology of 2μm ultrathin substrate in 2024 with a yield of 78%; and the three-step method (magnetron sputtering + evaporation + electroplating): Mitsui of Japan achieved the uniformity of copper layer of <1nm through molecular beam epitaxy, but the equipment cost is as high as 3 times that of traditional production lines.

[0004] The existing technology has the following drawbacks: Process compatibility: The electrolyte formula needs to be modified to match the PET substrate, and factors such as the fluctuation of vacuum stability during magnetron sputtering increase the cost of modification per GWh production line by 35 million yuan; Interface adhesion: The adhesion between the PP substrate and the copper layer is <8N / 25mm, which is 40% lower than that of traditional copper foil; Conductivity stability: After 500 cycles, the resistance of the composite copper foil increases by 15-20%, affecting fast charging performance. Summary of the Invention

[0005] The purpose of this invention is to provide a composite copper foil conductive layer structure, which aims to solve the problems of traditional copper foil such as large weight, insufficient flexibility, and poor conductivity uniformity.

[0006] The purpose of this utility model is achieved as follows: a composite copper foil conductive layer structure includes a substrate layer, a transition layer and a conductive layer, wherein the conductive layer is located on the surface of the substrate layer and the transition layer is located between the substrate layer and the conductive layer.

[0007] Micropores are formed on the surface of the substrate layer through plasma etching. These micropores can improve interlayer bonding.

[0008] The substrate layer material is polyimide or polyethylene terephthalate, and the thickness of the substrate layer is 2-10 μm.

[0009] The transition layer is formed on the surface of the substrate layer by magnetron sputtering. Magnetron sputtering creates metal grain sites to guide the crystallization of the conductive layer metal, providing anchoring points and aiding adhesion.

[0010] The transition layer material is a copper metal seed site, and the thickness of the transition layer is 0.3-0.5 μm.

[0011] The conductive layer surface is provided with cross-linked mesh grooves by laser engraving or chemical etching. This can reduce the interfacial contact resistance by more than 15%.

[0012] The conductive layer material is nanocrystalline copper, the thickness of the conductive layer is 0.5-3μm, and the sheet resistance of the conductive layer is ≤0.1Ω / sq.

[0013] The conductive layer has chamfered edges to prevent delamination between layers during roll winding.

[0014] The chamfer angle is 30°-60°.

[0015] The beneficial effects of this invention are as follows: The substrate layer surface is formed with a microporous structure through plasma etching, significantly increasing the contact area with the transition layer, improving interfacial bonding strength, and preventing interlayer delamination caused by mechanical stress or thermal expansion. The transition layer uses magnetron sputtering to form copper seed sites, ensuring efficient bonding between the conductive layer and the substrate layer, while reducing interfacial defects and improving the overall structural stability. Chamfering at the edges of the conductive layer reduces stress concentration, prevents edge warping or breakage, and improves durability.

[0016] This structure employs a multi-layered composite design, with a substrate layer providing mechanical support, a transition layer enhancing interfacial bonding, and a conductive layer optimizing conductivity. By combining a lightweight substrate with a highly conductive metal layer, a balance is achieved between high strength, high flexibility, and excellent electrical performance. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the conductive layer of a composite copper foil conductive layer according to the present invention.

[0018] Figure 2 This is a structural diagram of the copper metal seed and substrate layer of a composite copper foil conductive layer structure according to this utility model.

[0019] Figure 3 This is a cross-sectional view of the interlayer relationship of a composite copper foil conductive layer structure according to this utility model.

[0020] In the figure: 1. Groove; 2. Surface of conductive layer; 3. Cross-section of conductive layer; 4. Copper seed of conductive layer; 5. Copper seed of substrate layer; 6. Substrate layer; 7. Transition layer; 8. Conductive layer. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. Example 1

[0022] like Figure 1-3 As shown, a composite copper foil conductive layer structure includes a substrate layer 6, a transition layer 7, and a conductive layer 8. The conductive layer 8 is located on the surface of the substrate layer 6, and the transition layer 7 is located between the substrate layer 6 and the conductive layer 8.

[0023] Micropores are formed on the surface of the substrate layer 6 by plasma etching.

[0024] The transition layer 7 is formed on the surface of the substrate layer 6 by magnetron sputtering.

[0025] The surface of the conductive layer 8 is provided with cross-linked mesh grooves 1 by laser engraving or chemical etching.

[0026] In use, the substrate layer 6 provides mechanical support, the transition layer 7 enhances interfacial adhesion, and the conductive layer 8 optimizes conductivity. The thin film transition layer 7 is formed on the surface of the substrate layer 6 by magnetron sputtering, reducing interlayer stress and improving peel resistance. The conductive layer 8 has cross-linked mesh grooves 1 formed on its surface by laser engraving or chemical etching, increasing the effective contact area, reducing interfacial resistance, guiding lithium ions to uniformly deposit on the foil surface, lowering the nucleation barrier, and reducing lithium plating anomalies. The total structural thickness is controlled at 6-9 μm, and the mass ratio of the substrate layer 6 to the conductive layer 8 is ≤1:3, achieving lightweight design. Example 2

[0027] like Figure 1-3 As shown, a composite copper foil conductive layer structure includes a substrate layer 6, a transition layer 7, and a conductive layer 8. The conductive layer 8 is located on the surface of the substrate layer 6, and the transition layer 7 is located between the substrate layer 6 and the conductive layer 8.

[0028] Furthermore, micropores are formed on the surface of the substrate layer 6 by plasma etching. The micropore diameter is 50-200 nm, and the micropores can improve the interlayer bonding force.

[0029] Furthermore, the substrate layer 6 is made of polyimide or polyethylene terephthalate, and the thickness of the substrate layer 6 is 2-10 μm, preferably 4-6 μm, to ensure flexibility (bending radius ≤1 mm) and tensile strength (≥150 MPa).

[0030] Furthermore, the transition layer 7 is formed on the surface of the substrate layer 6 by magnetron sputtering. The magnetron sputtering forms metal grain sites, which guide the metal crystallization of the conductive layer 8, providing anchor points and assisting in adhesion.

[0031] Furthermore, the transition layer 7 is made of copper metal seed sites, and the thickness of the transition layer 7 is 0.3-0.5 μm.

[0032] Furthermore, the surface of the conductive layer 8 is provided with cross-linked mesh grooves 1 by laser engraving or chemical etching. The grooves 1 have a depth of 0.1-0.5 μm and a spacing of 1-5 μm. This can reduce the interfacial contact resistance by more than 15%.

[0033] Furthermore, the conductive layer 8 is made of nanocrystalline copper with a grain size of 20-100 nm, the thickness of the conductive layer 8 is 0.5-3 μm, and the sheet resistance of the conductive layer 8 is ≤0.1 Ω / sq.

[0034] Furthermore, the conductive layer 8 has chamfered edges to prevent interlayer peeling during roll winding.

[0035] Furthermore, the chamfer angle is 30°-60°.

[0036] In this invention, the substrate layer 6 provides mechanical support, the transition layer 7 enhances interfacial adhesion, and the conductive layer 8 optimizes conductivity. A thin film transition layer 7 is formed on the surface of the substrate layer 6 by magnetron sputtering, reducing interlayer stress and improving peel resistance. The surface of the conductive layer 8 is provided with cross-linked mesh grooves 1 through laser engraving or chemical etching, increasing the effective contact area, reducing interfacial resistance, guiding lithium ions to uniformly deposit on the foil surface, lowering the nucleation barrier, and reducing lithium plating anomalies. The total structural thickness is controlled at 6-9 μm, and the mass ratio of the substrate layer 6 to the conductive layer 8 is ≤1:3, achieving lightweight design.

[0037] This structure, through synergistic innovation in nanoscale interface control, gradient material design, and precision machining technology, significantly improves the mechanical reliability, processing accuracy, and environmental adaptability of composite copper foil while maintaining excellent conductivity. It also reduces the weight of traditional copper foil structures, increases overall flexibility, and balances conductivity uniformity.

Claims

1. A composite copper foil conductive layer structure, characterized in that: It includes a substrate layer, a transition layer and a conductive layer. The conductive layer is located on the surface of the substrate layer, and the transition layer is located between the substrate layer and the conductive layer. The surface of the substrate layer is formed with micropores by plasma etching. The transition layer is made of copper metal seed sites and has a thickness of 0.3-0.5 μm. The surface of the conductive layer is provided with cross-linked network grooves by laser engraving or chemical etching.

2. The composite copper foil conductive layer structure according to claim 1, characterized in that: The substrate layer material is polyimide or polyethylene terephthalate, and the thickness of the substrate layer is 2-10 μm.

3. The composite copper foil conductive layer structure according to claim 1, characterized in that: The transition layer is formed on the surface of the substrate layer by magnetron sputtering.

4. The composite copper foil conductive layer structure according to claim 1, characterized in that: The conductive layer material is nanocrystalline copper, the thickness of the conductive layer is 0.5-3μm, and the sheet resistance of the conductive layer is ≤0.1Ω / sq.

5. The composite copper foil conductive layer structure according to claim 4, characterized in that: The conductive layer has chamfered edges.

6. The composite copper foil conductive layer structure according to claim 5, characterized in that: The chamfer angle is 30°-60°.

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