Electrolytic Copper Foil Surface Texture Control
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Solution Overview
Problem
The production of electrolytic copper foils for lithium secondary batteries often results in defects such as curls, wrinkles, and tears due to uncontrolled manufacturing conditions, leading to increased costs and reduced battery quality.
Innovation Solution
An electrolytic copper foil with controlled surface texture and shape factors, including a texture coefficient of 0.4 to 1.32 for the (220) plane, a difference in Rz/Ra less than 2.42 between surfaces, and a peak density difference of 96 ea or less, manufactured using a method involving electroplating with a copper sulfate solution containing sulfuric acid, chlorine ions, a sulfide-based compound, molybdenum, and polyethylene glycol, and buffing the rotary negative electrode drum with a specific grit brush.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional electroplating methods are used to manufacture thin copper foil (10 μm or less), then production capacity is improved, but defects such as curls, wrinkles, and tears occur due to uncontrolled manufacturing conditions
Solution Approach 1:
The patent applies parameter changes by precisely controlling multiple electroplating parameters including current density (30-80 A/dm²), electrolyte composition (copper sulfate 50-150 g/L, sulfuric acid 80-150 g/L, chloride ions 5-20 ppm, leveling agents 1-10 ppm), temperature (20-60°C), and plating time to produce copper foil with thickness 10 μm or less while maintaining surface quality and preventing defects such as curls, wrinkles, and tears
Solution Approach 2:
The patent implements feedback control by monitoring and adjusting manufacturing parameters during the electroplating process, including real-time measurement of copper ion concentration, pH value, and current density, and making adjustments to maintain optimal plating conditions and prevent surface defects
2Manufacturing precision
If the roughness of copper foil is precisely controlled to be uniform, then manufacturing defects are reduced, but curls, wrinkles, or tears still occur in thin copper foil (10 μm or less)
Solution Approach 1:
The patent goes beyond simple roughness control by implementing a comprehensive parameter control system that includes texture coefficient control (TC(220) = 0.4-1.32), surface roughness parameters (Rz 3.0-15.0 μm, Ra 0.6-3.0 μm), and their ratios (Rz/Ra = 1.0-5.0), along with peak density control (5-20 ea), to prevent curls, wrinkles, and tears in thin copper foil while maintaining uniform surface quality
Solution Approach 2:
The patent applies preliminary action by pre-treating the copper foil surface during electroplating through controlled crystal texture development and surface morphology formation, creating an optimal surface structure that prevents subsequent defects such as curls, wrinkles, and tears during handling and battery manufacturing processes
3Quantity of substance
If thin copper foil (10 μm or less) is used to increase battery capacity, then energy density is improved, but handling characteristics deteriorate due to curls, wrinkles, or tears
Solution Approach 1:
The patent changes critical surface parameters including texture coefficient (TC(220) = 0.4-1.32), surface roughness (Rz 3.0-15.0 μm, Ra 0.6-3.0 μm), and peak density (5-20 ea) to produce thin copper foil with enhanced mechanical properties that maintain flexibility and adhesion while preventing curls, wrinkles, and tears during battery manufacturing handling
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The controlled surface characteristics and manufacturing process significantly reduce the occurrence of curls, wrinkles, and tears in the copper foil, enhancing its workability and adhesion with negative electrode active materials, thereby improving the quality and capacity of lithium secondary batteries.
Implementation Method 1
electrodepositing a copper film on the buffed rotary negative electrode drum
Implementation Method 2
buffing the surface of the rotary negative electrode drum using a brush having a grit of 500 # to 3000 #
Data Source
AI summary
The present invention relates to an electrolytic copper foil having excellent handling characteristics in the manufacture of copper foil and in post-processing for manufacturing a secondary battery. The present invention provides an electrolytic copper foil having a first surface and a second surface, wherein the texture coefficient of the (220) plane of the electrolytic copper foil is 0.4-1.32, the difference (|Δ(Rz/Ra)|) between Rz/Ra on the first surface and Rz/Ra on the second surface, of the electrolytic copper foil, is less than 2.42, and the difference (|ΔPD|) in peak density (PD) between the first surface and the second surface, of the electrolytic copper foil, is 96 ea or less.