Carbon-Layer Electrolytic Capacitor for High-Voltage Gas Suppression
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Solution Overview
Problem
Electrolytic capacitors for high voltage applications face issues with gas generation due to thin dielectric oxide films, leading to swelling, leakage, and reduced lifetime, while adding gas absorption agents like nitro compounds compromises withstand voltage.
Innovation Solution
The electrolytic capacitor design includes a cathode foil with a carbon layer and a capacitance ratio of 10:1 between the anode and cathode sides, using a carbon layer on the cathode foil to suppress gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric oxide film is thinned to increase capacitance, then capacitance increases, but gas generation increases and lifetime decreases
Solution Approach 1:
A carbon layer is introduced as an intermediary substance between the electrolytic solution and the cathode foil. This carbon layer acts as a mediator that suppresses gas generation at the cathode side while allowing the dielectric oxide film to be thin for high capacitance. The carbon layer absorbs or neutralizes gas molecules before they can accumulate and cause damage to the capacitor structure.
2Object-generated harmful factors
If gas absorption agents like nitro compounds are added to suppress gas generation, then gas generation decreases, but withstand voltage decreases
Solution Approach 1:
The harmful function of gas absorption is extracted from the electrolytic solution (by removing nitro compounds) and transferred to a dedicated component - the carbon layer on the cathode foil. This separation allows the electrolytic solution to maintain its high voltage properties while the carbon layer specifically handles gas suppression without compromising withstand voltage.
3Strength
If the dielectric oxide film is thickened to increase withstand voltage, then withstand voltage increases, but capacitance decreases
Solution Approach 1:
The invention changes the parameter of dielectric oxide film thickness to be thin (enabling high capacitance) while simultaneously changing the cathode side configuration (adding carbon layer) to compensate for gas generation issues. This parameter change allows operating at the optimal thin film thickness for capacitance without suffering from the usual gas generation problems.
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 design effectively suppresses gas generation, maintaining high voltage withstand and capacitance, thereby extending the capacitor's lifetime.
Implementation Method 1
dielectric oxide film which is formed on a surface of the enlarged surface layer
Implementation Method 2
a carbon layer which is formed on the cathode foil
Implementation Method 3
The electrolytic solution intervenes between the anode foil and the cathode foil, closely contacts with an uneven surface of the anode foil, and acts as a true cathode
Data Source
AI summary
The present disclosure provides an electrolytic capacitor for middle or high voltage application of 160 V or more, which can suppress the total amount of gas generated inside the electrolytic capacitor. An electrolytic capacitor includes anode foil on which dielectric oxide film is formed, and a cathode body. The cathode body includes cathode foil formed of valve action metal and a carbon layer formed on the cathode foil. The anode foil and the cathode body have capacitance so that when capacitance X of the anode foil per unit area is 1, ratio of capacitance Y of the cathode body per the same unit area is equal to or more than 10.