Vacuum Coating of Thin Metal Foils for Battery Electrodes
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Solution Overview
Problem
Thin metal foils used in energy storage devices like batteries face challenges with conventional protective layer deposition methods, which damage the foils due to mechanical weakness, form insulating layers, and result in high interfacial resistance, impairing efficiency and corrosion resistance.
Innovation Solution
A vacuum-based process for depositing amorphous carbon layers on thin metal foils, optionally with a metal buffer layer, to form a corrosion-resistant and electrically conductive protective layer, which reduces surface resistance and enhances adhesion, using gaseous coating materials and techniques like sputtering or electron beam vaporization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wet-chemical deposition methods are used to apply protective layers, then corrosion protection is improved, but the thin foils are damaged due to their low mechanical strength
Solution Approach 1:
The patent replaces wet-chemical deposition methods with a vacuum-based deposition process. This substitution eliminates the need for liquid solvents and mechanical handling that damage thin foils, while still achieving effective protective layer formation through vapor-phase deposition in vacuum conditions.
Solution Approach 2:
The patent employs a vacuum environment for depositing the protective layer. This inert atmosphere prevents chemical reactions between the organic solvents used in conventional methods and the foil material, eliminating the formation of insulating layers and avoiding mechanical damage to the thin foils during the coating process.
2Reliability
If organic solvents are used in wet-chemical deposition, then particles can be applied to form protective layers, but the solvents react chemically with the foil to form insulating layers that increase surface resistance
Solution Approach 1:
The patent uses a vacuum environment to eliminate chemical reactions between organic solvents and the foil material. By depositing particles in vacuum conditions, the method prevents the formation of insulating reaction layers, thereby maintaining low surface resistance while still achieving effective protective layer formation.
Solution Approach 2:
The patent replaces wet-chemical deposition with vacuum-based particle deposition. This substitution eliminates the use of organic solvents that cause harmful chemical reactions, allowing protective layers to be formed without increasing surface resistance.
3Reliability
If carbon is applied in particle form to foils, then protective coverage is achieved, but the layer thickness becomes very thick (micron range) resulting in high interfacial resistance and resistive losses
Solution Approach 1:
The patent changes the deposition parameters by using vacuum-based deposition instead of wet-chemical methods. This enables the formation of uniformly distributed, thin protective layers with controlled thickness in the nanometer to sub-micron range, significantly reducing interfacial resistance and resistive losses while maintaining effective corrosion protection.
4Loss of energy
If carbon is applied in floc form to reduce layer thickness, then resistive losses are reduced, but the layer becomes porous with many openings exposing the foil to corrosion
Solution Approach 1:
The patent optimizes deposition parameters in vacuum conditions to achieve a balanced protective layer structure. By controlling particle size, deposition rate, and vacuum conditions, the method forms layers with thickness in the nanometer to sub-micron range that have sufficient density to prevent corrosion while maintaining low interfacial resistance and minimizing porosity.
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 process achieves a significant reduction in surface resistance by up to a factor of 10 compared to conventional methods, improving the mechanical strength and electrical conductivity of the foils, thereby enhancing the efficiency and corrosion resistance of energy storage devices.
Implementation Method 1
coating of the foil structure using a gaseous coating material... formation of an electrically conductive protective layer on top of the metallic surface of the foil structure, with the formation of the electrically conductive protective layer occurring from at least the material vapor
Implementation Method 2
using gaseous coating materials and techniques like sputtering or electron beam vaporization
Implementation Method 3
using gaseous coating materials and techniques like sputtering or electron beam vaporization
Data Source
AI summary
Herein is disclosed a process comprising transporting of a foil structure in a coating region in a vacuum chamber, wherein the foil structure has a thickness of less than 40 μm; and coating the foil structure with a protective layer using a gaseous coating material; wherein the gaseous coating material comprises a metal; applying an active material on the foil structure to form a first electrode which has a first chemical potential; assembling the first electrode with a second electrode, where the second electrode has a second chemical potential; and encapsulating the first electrode and the second electrode.