Roughened Anode Lead Tab for Capacitor Corrosion Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The life time of aluminium electrolytic capacitors is shortened due to electrochemical corrosion of the anode lead tab caused by halogen ions, which initiate self-accelerating reactions with the material, leading to disintegration.
Innovation Solution
The anode lead tab is configured with a roughened surface to distribute impurities uniformly, reducing concentration hotspots and protected by an oxide layer to prevent unwanted side reactions, thereby increasing the specific surface area and minimizing the risk of corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide layer is applied to protect the aluminum anode from environmental impacts, then corrosion protection is improved, but voids and cracks in the oxide layer create weak points that accelerate corrosion
Solution Approach 1:
The patent applies a roughened surface structure to the anode lead tab, creating local variations in surface topology. This roughness distributes impurities uniformly across the surface rather than allowing them to concentrate in specific areas, thereby eliminating the harmful concentration hotspots that would otherwise accelerate corrosion at defect sites in the oxide layer
Solution Approach 2:
The patent converts the typically harmful effect of surface impurities into a beneficial distribution pattern. By roughening the surface, impurities that would normally concentrate at oxide layer defects are instead uniformly dispersed across the entire surface, transforming a potential corrosion acceleration mechanism into a protective uniform distribution that prevents localized attack
2Ease of manufacture
If the surface of the anode lead tab is left smooth, then manufacturing is simpler, but impurities concentrate at specific locations causing accelerated corrosion
Solution Approach 1:
The patent changes the surface topology parameter from smooth to roughened. This parameter change fundamentally alters how impurities interact with the surface, transforming concentration hotspots into uniform distribution. The roughness parameter is optimized to provide sufficient surface area for uniform impurity distribution while maintaining manufacturing feasibility through established roughening techniques
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 solution significantly extends the capacitor's lifetime by suppressing side reactions and reducing the risk of short circuits, achieving a lifespan of over 3000 hours under high voltage and temperature conditions.
Implementation Method 1
providing a roughened surface that protects the anode lead tab from surface dissolution
Implementation Method 2
The electrochemical corrosion of anodic lead tabs is caused by halogen ions which start electrochemical reactions with the material of aluminium anode lead tabs
Implementation Method 3
an insulating oxide layer is formed by anodization. The oxide layer acts as the dielectric of the aluminium electrolytic capacitor
Implementation Method 4
an insulating oxide layer is formed by anodization
Implementation Method 5
The liquid electrolyte covers the surface of the oxide layer and in principle serves as the second electrode of the capacitor
Data Source
AI summary
In an embodiment an anode lead tab is configured for externally contacting an anode foil in an electrolytic capacitor, wherein the anode lead tab has a roughened surface configured to protect the anode lead tab from surface dissolution.