Electrolytic Capacitor Anode Wire Structure for Low ESR
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Solution Overview
Problem
The production of fluted anodes for electrolytic capacitors requires complex molds and mechanisms, significantly increasing production costs while aiming for low equivalent series resistance (ESR).
Innovation Solution
Employ a porous anode body made of a first metal with an anode wire composed of a second metal having higher conductivity than the first, or a core part and surface layer of different metals with a common constituting element or capable of forming an all-proportional solid solution alloy, to reduce ESR without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fluted anode is used to reduce ESR, then the equivalent series resistance decreases, but the production cost increases significantly due to complicated molds and mechanisms
Solution Approach 1:
The anode wire is designed with non-uniform cross-sectional area, featuring a larger diameter at the embedded portion contacting the anode body and a smaller diameter at the protruding portion. This local variation in geometry optimizes electrical contact and current distribution at the critical interface region, reducing ESR without requiring complex fluted anode structures throughout the entire component.
Solution Approach 2:
The invention changes the material parameter by using a second metal for the anode wire with higher conductivity than the first metal forming the anode body. This material parameter change directly reduces ESR while the simplified anode wire geometry maintains ease of manufacture, avoiding the need for expensive fluted anode production processes.
2Loss of energy
If a fluted anode is used to reduce ESR, then the equivalent series resistance decreases, but the device complexity increases due to complicated molds and mechanisms
Solution Approach 1:
The anode wire features localized geometric variation with larger diameter at the embedded portion and smaller diameter at the protruding portion. This local quality optimization focuses complexity only where needed for electrical performance, avoiding the need for complex fluted structures in the anode body itself and thereby reducing overall device complexity.
Solution Approach 2:
Instead of making the anode body complex (fluted structure) to achieve low ESR, the invention inverts the approach by making the anode wire the optimized component with specific geometric and material properties. This inversion simplifies the anode body manufacturing while achieving the same ESR reduction goal.
3Loss of energy
If an anode wire with higher conductivity metal is used, then the ESR decreases, but the material cost may increase
Solution Approach 1:
The anode wire uses higher conductivity second metal specifically at the embedded portion where it contacts the anode body, which is the critical region for electrical resistance. The protruding portion uses lower conductivity first metal, reducing the quantity of expensive high-conductivity material needed while maintaining ESR reduction benefits at the critical interface.
Solution Approach 2:
The anode wire is constructed as a composite structure with different metals in different regions: second metal (higher conductivity) at the embedded portion and first metal (lower conductivity) at the protruding portion. This composite approach optimizes the balance between electrical performance and material cost by placing high-conductivity material only where most needed.
Data Source
AI summary
An electrolytic capacitor includes a capacitor element including a porous anode body, an anode wire partially embedded in the anode body, a dielectric layer formed on a surface of the anode body, and a solid electrolyte layer covering at least a portion of the dielectric layer, wherein the anode body is formed of a first metal, the anode wire is formed of a second metal having a different composition from the first metal, and the second metal has a conductivity S2 that is larger than a conductivity S1 of the first metal. This allows for providing an electrolytic capacitor which suppresses an increase in production costs and has a low ESR.