Electrolytic Capacitor Electrode Foil With P-C Underlayer for Low Leakage
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Solution Overview
Problem
Existing electrolytic capacitors face increased leakage current when the metal element in the dielectric layer differs from the metal in the anode body, limiting capacitance and performance.
Innovation Solution
An electrode foil with a porous anode body and a dielectric layer containing an oxide of a second metal, where the underlayer includes phosphorus and carbon, is used, allowing for a gas phase method to form the dielectric layer and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dielectric layer containing an oxide of a second metal different from the first metal in the anode body is formed, then capacitance is improved, but leakage current increases
Solution Approach 1:
An underlayer containing phosphorus and carbon is introduced as an intermediary between the first metal framework and the second metal oxide dielectric layer. This underlayer acts as a mediator that enables the formation of a dielectric layer with different metal composition while preventing excessive leakage current, thus resolving the contradiction between achieving high capacitance and maintaining low leakage current.
Solution Approach 2:
The patent employs a composite structure consisting of the first metal framework, the phosphorus-carbon-containing underlayer, and the second metal oxide dielectric layer. This composite material approach allows combining the high capacitance benefits of different metal oxides while using the underlayer to suppress leakage current, achieving both improved capacitance and controlled leakage.
2Object-generated harmful factors
If an underlayer containing phosphorus and carbon is formed between the metal framework and the dielectric layer, then leakage current is reduced, but manufacturing complexity increases
Solution Approach 1:
The underlayer containing phosphorus and carbon is formed as a preliminary step before depositing the second metal oxide dielectric layer. By preparing this underlayer in advance, the subsequent dielectric layer formation is facilitated, and the overall manufacturing process becomes more controlled, justifying the additional step through improved product performance.
Solution Approach 2:
The patent replaces traditional chemical conversion treatment methods with a gas phase deposition method for forming the dielectric layer on the phosphorus-carbon underlayer. This substitution enables better control over the dielectric layer formation process and reduces leakage current while maintaining manufacturing feasibility.
3Manufacturing precision
If a gas phase method is used to form the dielectric layer, then manufacturing precision is improved, but production time increases
Solution Approach 1:
The gas phase deposition process allows precise control of deposition parameters such as temperature, pressure, and gas flow rates to achieve uniform dielectric layer formation. By optimizing these parameters, high manufacturing precision is achieved while minimizing unnecessary process time, balancing quality and productivity.
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 configuration effectively reduces leakage current and enhances capacitance by stabilizing the surface and promoting uniform growth of the dielectric layer, improving acid resistance and overall performance.
Implementation Method 1
forming an underlayer on a surface of a metal framework consisting the porous part by heating the anode body to which the alkali solution adheres
Implementation Method 2
forming, on a surface of the underlayer, a dielectric layer including a first layer containing an oxide of a second metal by a gas phase method
Data Source
AI summary
An electrode foil for an electrolytic capacitor includes an anode body foil having a porous part, and a dielectric layer covering a surface of a metal framework constituting the porous part. The dielectric layer includes a first layer containing an oxide of a second metal, the second metal being different from a first metal contained in the metal framework. An underlayer that is continuous with the first layer is provided between the metal framework and the first layer. The underlayer contains phosphorus and carbon.