Copper Collector Coated with Cu-Nitrile Complex for Overdischarge Protection
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Solution Overview
Problem
Lithium secondary batteries without protection circuits suffer from rapid capacity loss and inability to recharge after overdischarge due to copper foil oxidation, leading to decreased battery usability.
Innovation Solution
A copper foil or net coated with a Cu-nitrile compound complex is used as an anode collector, formed by applying a specific reduction potential, preventing copper oxidation even at high voltages and maintaining battery quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper foil is used as an anode collector without any coating, then the battery can operate with simple structure and low cost, but the copper foil oxidizes at high voltage during overdischarge, causing rapid capacity loss and battery failure
Solution Approach 1:
The copper foil collector is coated with a composite layer containing nitrile compound and conductive material (such as carbon black or metal particles). This composite coating provides both oxidation protection and electrical conductivity, allowing the copper foil to resist corrosion at high voltage while maintaining the simple overall collector structure. The composite material combines the protective properties of nitrile compounds with the conductive properties of carbon or metal to resolve the contradiction between reliability and device complexity.
Solution Approach 2:
The surface properties of the copper foil are modified by coating it with nitrile compound, which changes the electrochemical potential and oxidation resistance parameters of the copper surface. This parameter change allows the copper collector to withstand higher voltages without oxidation, improving battery reliability after overdischarge while maintaining the simple copper foil base structure.
2Reliability
If a protection circuit is attached to prevent overdischarge, then the battery safety is improved, but the device volume and cost increase
Solution Approach 1:
The copper foil collector is designed to inherently protect itself through the nitrile compound coating, which prevents oxidation and maintains functionality even during overdischarge conditions. This self-protecting mechanism eliminates the need for external protection circuits, allowing the battery to achieve safety improvements without increasing volume or cost. The collector serves its own protection function rather than requiring a separate protection system.
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 Cu-nitrile compound complex significantly improves battery capacity restorability after overdischarge without degrading battery quality, as the copper remains stable beyond its typical oxidation potential, ensuring effective charge/discharge cycles.
Implementation Method 1
a Cu-nitrile compound complex is formed on the surface of the copper foil or net
Implementation Method 2
preventing copper oxidation even at high voltages
Implementation Method 3
copper foil used as an anode collector
Data Source
AI summary
Disclosed are copper foil or net comprising a Cu-nitrile compound complex formed on the surface thereof, a method for preparing the same, and a lithium secondary battery that comprises an electrode using the same copper foil or net as a collector. The lithium secondary battery, which uses a copper collector comprising a Cu-nitrile compound complex formed on the surface thereof through the application of a certain voltage level, can prevent the corrosion of Cu occurring at a voltage of 3.6V or higher under overdischarge conditions away from the normal drive condition, and thus can significantly improve the capacity restorability after overdischarge.