Electrolytic Copper Foil Chromium Adhesion for Battery Reliability
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Solution Overview
Problem
Lithium secondary batteries experience rapid reduction in charge and discharge capacity due to repeated charging and discharging cycles, leading to low capacity retention rates and short lifetimes, resulting in frequent replacements and resource waste.
Innovation Solution
An electrolytic copper foil with a matte and shiny surface, coated with chromium-based protective layers, is used as a negative electrode current collector, enhancing adhesion with active material layers through controlled peak count, chromium electrodeposition, and surface roughness, thereby improving the charge and discharge efficiency and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytic copper foil is used without optimized surface treatment, then manufacturing process is simple, but adhesion between copper foil and active material layer is insufficient leading to low capacity retention rate
Solution Approach 1:
The patent applies parameter changes by precisely controlling surface roughness (Rz: 0.5-5.0 μm), peak count (Pc: 5-110), and chromium electrodeposition amount (DACr: 0.5-3.8 mg/m2) to optimize adhesion between copper foil and active material layer, achieving capacity retention rate of 90% or more after 500 charge-discharge cycles
Solution Approach 2:
The patent uses composite materials by forming a chromium-based protective layer on the copper foil surface through electrodeposition, creating a composite structure that combines copper's electrical conductivity with chromium's adhesion properties and corrosion resistance, thereby improving both reliability and surface performance
2Reliability
If chromium electrodeposition amount is increased to improve adhesion, then adhesion factor improves, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent optimizes the chromium electrodeposition amount parameter (DACr: 0.5-3.8 mg/m2) to achieve the最佳 balance between adhesion improvement and manufacturing feasibility, avoiding excessive chromium deposition that would increase cost and complexity while still achieving capacity retention rate of 90% or more
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 electrolytic copper foil ensures a high capacity retention rate of 90% or more, minimizing the need for frequent battery replacements and reducing resource waste by maintaining a stable charge and discharge capacity over time.
Implementation Method 1
a first protective layer on the matte surface of the copper layer, wherein the first protective layer includes chromium (Cr)... a DACr of the first surface ranges from 0.5 to 3.8 mg/m2
Data Source
AI summary
An electrolytic copper foil capable of securing a secondary battery having a high capacity retention rate, an electrode including the same, a secondary battery including the same, and a method of manufacturing the same. The electrolytic copper foil, which includes a first surface and a second surface opposite to the first surface, includes a copper layer including a matte surface facing the first surface and a shiny surface facing the second surface, and a first protective layer on the matte surface of the copper layer, wherein the first protective layer includes chromium (Cr) and the first surface of the electrolytic copper foil has an adhesion factor of 1.5 to 16.3.