Electrolytic Copper Foil Balancing Strength, Elongation, and Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current copper foils used in secondary batteries face challenges such as high manufacturing costs, contamination from lubricating oils, surface roughness issues, and mechanical weakness, which affect adhesion, durability, and performance during heat treatment and charge/discharge cycles.
Innovation Solution
Development of an electrolytic copper foil with a room-temperature tensile strength of 40 kgf/mm2 or greater and elongation per unit thickness ranging from 1.3 to 2.0%/μm, maintaining high mechanical strength and elongation even after heat treatment at 200°C, and capable of withstanding repeated bending cycles, with controlled surface roughness and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rolled copper foil is used as current collector, then manufacturing cost is reduced, but adhesion to active material deteriorates due to lubricating oil contamination
Solution Approach 1:
The patent replaces the mechanical rolling process with an electrolytic deposition process. Instead of mechanically rolling copper foil with lubricating oil, the invention uses electrolysis to deposit copper foil directly, eliminating the need for lubricating oil and the associated adhesion problems while maintaining manufacturing feasibility
Solution Approach 2:
The patent changes the fundamental manufacturing parameter from mechanical rolling to electrolytic deposition. This parameter change transforms the production method to eliminate harmful lubricating oil contamination while achieving the desired copper foil properties for battery current collectors
2Manufacturing precision
If copper foil thickness is reduced for fine wiring, then etching time is reduced and wiring precision is improved, but mechanical strength decreases causing wrinkles and bending
Solution Approach 1:
The patent changes the microstructure parameters of the copper foil through controlled electrolytic deposition. By controlling deposition conditions, the invention achieves a fine-grained microstructure that provides high strength at thin thicknesses, enabling use in fine wiring applications without mechanical failure
Solution Approach 2:
The patent creates a composite microstructure within the copper foil by controlling the electrolytic deposition process. The resulting fine-grained structure acts as a composite at the microscale, providing enhanced mechanical properties that prevent wrinkles and bending in thin foils used for fine wiring
3Quantity of substance
If vacuum drying is performed at high temperature for long time, then moisture removal is improved, but adhesion and stress between copper foil and active material change reducing battery life
Solution Approach 1:
The patent performs preliminary surface treatment during the electrolytic deposition process itself. The electrolytic deposition creates a surface structure and composition that is pre-optimized for adhesion, reducing the need for aggressive post-deposition drying treatments that would compromise the copper foil-active material interface
Solution Approach 2:
The patent changes the surface properties of the copper foil through controlled electrolytic deposition parameters. By adjusting current density, temperature, and electrolyte composition during deposition, the invention creates a surface that maintains strong adhesion even after vacuum drying, preventing degradation of the copper foil-active material interface
4Reliability
If electrolytic copper foil is used instead of rolled copper foil, then adhesion to active material is improved, but manufacturing complexity increases
Solution Approach 1:
The patent makes the electrolytic deposition process serve multiple functions simultaneously. The same electrolytic cell that deposits the copper foil also controls microstructure, surface properties, and thickness uniformity in one integrated process, reducing overall manufacturing complexity despite using electrolysis instead of rolling
Solution Approach 2:
The patent merges multiple manufacturing steps into a single electrolytic deposition process. Instead of separate steps for foil production, surface treatment, and quality control, the invention combines these functions into one integrated electrolytic process, simplifying the overall manufacturing workflow
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 copper foil exhibits improved mechanical strength, elongation, and durability across various temperatures and thicknesses, ensuring stable battery performance and resistance to defects like wrinkles and cracking, while maintaining excellent adhesion with active materials.
Implementation Method 1
an electrolytic copper foil according to claim 1
Data Source
AI summary
Disclosed herein are a high-strength, high-elongation electrolytic copper foil and a manufacturing method therefor. The electrolytic copper foil has a tensile strength of 40 kgf/mm2 or greater at room temperature and ranges in elongation per unit thickness at room temperature from 1.3 to 2.0%/μm.