Electrode Slurry Light Drying to Prevent Current Collector Oxidation
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Solution Overview
Problem
High-temperature drying of rechargeable battery electrodes leads to oxidation of copper current collectors, increasing interfacial resistance and affecting battery performance, particularly with the use of silicon-based negative electrodes requiring high-temperature binder polymerization.
Innovation Solution
A method involving selective heating of the slurry using light with wavelengths between 320 nm and 450 nm, absorbed primarily by the slurry, minimizing heat transfer to the current collector, and a drying apparatus with LED light sources and cooling mechanisms to control temperature and prevent UV-induced degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature drying is used to polymerize polyimide binder, then binder strength and stress relaxation capability are improved, but current collector oxidation increases leading to higher interfacial resistance
Solution Approach 1:
The patent replaces thermal drying with light irradiation drying. Instead of using a heater to raise the overall temperature for polymerization, the invention uses light sources (LED, UV, or visible light) to irradiate the slurry, causing photopolymerization of the polyimide binder. This substitutes a thermal field with an optical field, enabling binder polymerization without heating the current collector to oxidation-prone temperatures.
Solution Approach 2:
The patent applies local quality by directing light irradiation specifically to the slurry layer where the binder resides, rather than heating the entire electrode structure uniformly. The light energy is absorbed locally in the slurry to drive polymerization, while the current collector remains relatively cool and protected from oxidation. This localized energy input resolves the contradiction between achieving high binder strength and preventing current collector degradation.
2Manufacturing precision
If conventional thermal drying is used, then slurry drying is achieved, but temperature rise of current collector causes oxidation and performance degradation
Solution Approach 1:
The patent replaces the thermal drying system with a photopolymerization system. Instead of using heaters or hot air to evaporate solvent and dry the slurry, the invention uses light irradiation to directly polymerize the binder in situ. This substitution eliminates the need for high-temperature thermal processing, achieving both effective slurry drying and binder polymerization while maintaining current collector integrity and preventing oxidation-related performance degradation.
Solution Approach 2:
The patent changes the energy input parameter from thermal energy (temperature) to optical energy (light wavelength and intensity). By selecting appropriate light sources (LED, UV, or visible light with specific wavelengths), the process achieves binder polymerization and slurry drying at ambient or low temperatures, fundamentally altering the processing parameters to avoid current collector oxidation while maintaining manufacturing quality.
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
This approach effectively suppresses temperature rise and oxidation of the current collector, maintaining battery performance by selectively heating the slurry while preventing binder deterioration, thus enhancing the manufacturing process for rechargeable batteries.
Implementation Method 1
heating and drying the slurry by irradiating a side of the slurry of the workpiece with light having a wavelength range in which light absorption in the slurry is equal to or greater than 60%
Implementation Method 2
a drying apparatus with LED light sources and cooling mechanisms to control temperature and prevent UV-induced degradation
Data Source
AI summary
Disclosed herein is a method of manufacturing an electrode for a rechargeable battery. The method comprises: a preparation process for preparing a workpiece on which a slurry containing a negative electrode active material is applied to at least one surface of a negative electrode current collector; and a drying process for heating and drying the slurry by irradiating a side of the slurry of the workpiece with light having a wavelength range in which light absorption in the slurry is equal to or greater than 60%.