Electrolytic Capacitor Conductive Polymer Layer Formation
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Solution Overview
Problem
Existing electrolytic capacitors face challenges in achieving large capacitance and superior impedance characteristics in high frequency regions due to non-uniform conductive polymer layer formation and potential damage to dielectric films during chemical polymerization or electropolymerization processes.
Innovation Solution
A method involving an anode foil with roughened surfaces and multiple conductive polymer layers formed using dispersion solutions with different pH values, where the first dispersion solution is nearly neutral to minimize dielectric film damage and the second, more acidic or basic solution facilitates efficient formation of thicker conductive polymer layers, reducing leakage current and material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If chemical polymerization or electropolymerization is used to form conductive polymer layer, then capacitance can be increased, but dielectric film may be damaged by oxidizing agent and polymer layer formation becomes non-uniform
Solution Approach 1:
The patent changes the chemical parameters of the dispersion solution, specifically using different pH values (first solution with pH closer to neutral, second solution with pH further from neutral) to control the polymerization process. This allows uniform conductive polymer layer formation without damaging the dielectric film, resolving the contradiction between achieving high capacitance and maintaining dielectric film integrity.
Solution Approach 2:
The patent divides the conductive polymer layer formation into two separate immersion steps using two different dispersion solutions with different pH values. The first solution forms an initial layer with minimal dielectric damage, while the second solution completes the layer formation. This segmented approach resolves the contradiction by separating the polymerization process into controlled stages.
2Ease of manufacture
If single dispersion solution is used to form conductive polymer layer, then manufacturing process is simple, but uniform polymer layer formation is difficult and large amount of polymer is required
Solution Approach 1:
The patent segments the polymer layer formation into two immersion steps using dispersion solutions with different pH values. The first solution (pH closer to neutral) creates a uniform initial layer, while the second solution (pH further from neutral) completes the formation. This segmentation achieves uniform polymer distribution without requiring excessive polymer material, while maintaining reasonable manufacturing simplicity.
Solution Approach 2:
The patent changes the pH parameter between the two dispersion solutions to optimize polymer layer formation at different stages. The first solution uses pH closer to neutral for initial uniform coverage, while the second solution uses pH further from neutral to complete formation efficiently. This parameter change resolves the contradiction between process simplicity and manufacturing precision.
3Quantity of substance
If thicker conductive polymer layer is formed to reduce impedance in high frequency region, then capacitance increases, but more material is required and cost increases
Solution Approach 1:
The patent uses pH parameter changes in the dispersion solution to optimize conductive polymer layer formation. The two-stage process with different pH values achieves uniform polymer distribution and efficient layer formation, reducing the total amount of conductive polymer material needed while still achieving the required capacitance and impedance characteristics.
Solution Approach 2:
The patent segments the polymer layer formation into two controlled immersion steps, allowing efficient material utilization. The first solution establishes uniform baseline coverage, while the second solution completes the layer with optimized material distribution. This segmentation reduces overall polymer material consumption while achieving the desired capacitance.
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 approach results in electrolytic capacitors with improved capacitance, reduced equivalent series resistance (ESR), and minimal leakage current, while allowing for a smaller capacitor size and reduced material usage, enhancing both performance and productivity.
Implementation Method 1
immersing the anode foil in a first dispersion solution containing first conductive polymer particles and first solvent to form a first conductive polymer layer
Data Source
AI summary
A method of manufacturing an electrolytic capacitor includes preparing a dielectric film formed on a surface of an anode foil, forming a first conductive polymer layer on a surface of the dielectric film by immersing the anode foil in first dispersion solution including conductive polymer particles and forming a second conductive polymer layer covering the first conductive polymer layer solvent by immersing the anode foil in second dispersion solution including second conductive polymer particles and second solvent. The surface of the anode foil has plural pits formed therein. The second dispersion solution has a pH value farther from 7 than the first dispersion solution does. This configuration can suppress damages to the dielectric film.