Electrolytic Copper Foil Pore Structure for Battery Adhesion
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Solution Overview
Problem
Current copper foils used in batteries and electronic components face challenges such as high manufacturing costs, reduced adhesion to active materials, mechanical weakness, and surface roughness issues, which affect their performance and reliability, especially during high-temperature heat treatment and miniaturization processes.
Innovation Solution
A low-roughness, high-strength, and high-elongation electrolytic copper foil is developed with a matte side having an average pore diameter of 1 nm to 100 nm, a glossiness of 500 or more, and specific tensile strength and elongation properties that are maintained even after heat treatment, achieved through a controlled electroplating process with additives like thiourea-based compounds and sulfonic acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rolling working is used to manufacture copper foil, then manufacturing cost is reduced, but adhesion to active material is reduced due to lubricating oil pollution
Solution Approach 1:
The patent changes the surface parameters of the copper foil by controlling the electrolytic deposition process to create a specific surface structure with protruding elements and pores. This surface structure provides mechanical interlocking with the active material, improving adhesion without requiring lubricating oil or additional surface treatments.
2Productivity
If copper foil thickness is reduced for micro patterning, then circuit integration is improved, but mechanical strength is reduced causing wrinkles and bending
Solution Approach 1:
The patent introduces a controlled porous structure on the copper foil surface with specific pore size and distribution. This porous structure increases the effective surface area and provides anchoring points for the active material, enhancing mechanical strength and wrinkle resistance while maintaining thin foil thickness for high circuit integration.
Solution Approach 2:
The patent creates a composite surface structure combining copper base material with a controlled porous overlay layer. This composite structure integrates the mechanical strength of copper with the surface area benefits of porous materials, allowing thin foils to maintain high strength for micro patterning applications.
3Reliability
If surface roughness is reduced for better adhesion, then adhesion to active material is improved, but mechanical strength is reduced
Solution Approach 1:
The patent applies local quality by creating protruding surface elements and pores at specific locations on the copper foil surface rather than uniform roughness. The bulk material remains dense and strong, while the surface has localized features that enhance adhesion through mechanical interlocking with the active material.
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 adhesion, mechanical strength, and thermal stability, reducing defects and enhancing the reliability of batteries and electronic components, while allowing for the formation of high-density circuits and efficient heat management.
Implementation Method 1
achieved through a controlled electroplating process with additives like thiourea-based compounds and sulfonic acids
Data Source
AI summary
Disclosed herein is an electrolytic copper foil in which an average diameter of a pore which is a region between surface elements protruding from a matte side is 1 mm to 100 nm. The electrolytic copper foil has high elongation while maintaining low roughness and high strength and thus may be used in a current collector of a medium-large size lithium ion secondary battery and a semiconductor packaging substrate, and the like, for tape automated bonding (TAB) which is used in a tape carrier package (TCP).