Solid Electrolytic Capacitor with Ultra-Fine Conductive Polymer
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Solution Overview
Problem
Miniaturization and increased capacitance of solid electrolytic capacitors lead to finer, more complex dielectric layers, making it difficult to impregnate conductive polymers effectively, especially in rolled-type capacitors with separators, resulting in reduced capacitance performance.
Innovation Solution
A conductive-polymer solution with a volume average particle size less than 26 nm, surface tension below 67 mN/m, and containing a surfactant is applied to oxidized dielectric layers, ensuring deep impregnation and high capacitance rates, with the polymer solution preferably containing a repeating unit with acidic groups for enhanced solubility and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional polymer slurry coating method is used, then manufacturing process is simplified, but conductive polymer cannot impregnate deep into fine irregularities of dielectric layer
Solution Approach 1:
The patent changes the particle size parameter of the conductive polymer to less than 26 nm, enabling the polymer to penetrate deep into the fine irregularities of the dielectric layer while maintaining the simplicity of the coating method. This parameter change resolves the contradiction between manufacturing simplicity and impregnation depth.
Solution Approach 2:
The conductive polymer is segmented into ultra-fine particles (less than 26 nm) that can individually penetrate into the fine pores and irregularities of the dielectric layer. This segmentation allows deep impregnation without requiring complex chemical reactions or electrolytic processes.
2Quantity of substance
If dielectric layer is made finer for miniaturization, then capacitance is increased, but impregnation of conductive polymer becomes more difficult
Solution Approach 1:
By changing the particle size parameter of the conductive polymer to ultra-fine (less than 26 nm), the patent enables effective impregnation into the finer dielectric layers required for miniaturization and high capacitance. The ultra-fine particles can navigate the complex fine structures without requiring simplified dielectric structures.
3Ease of manufacture
If chemical oxidation-polymerization method is used, then solid electrolytic layer can be formed, but impurities are mixed in causing short-circuiting
Solution Approach 1:
The conductive polymer is prepared in advance as ultra-fine particles (less than 26 nm) in a slurry form, eliminating the need for in-situ polymerization reactions on the dielectric layer. This preliminary preparation prevents impurities from being generated during the layer formation process, thereby preventing short-circuiting while maintaining ease of manufacture.
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 allows for sufficient impregnation of conductive polymers into the dielectric layers, achieving a capacitance rate of at least 70% and simplifying the manufacturing process while maintaining high conductivity and film formability.
Implementation Method 1
a conductive-polymer solution which contains a conductive polymer that satisfies following condition (A) and which meets following condition (B) is applied and dried
Implementation Method 2
a conductive-polymer solution which contains a conductive polymer that satisfies following condition (A) and which meets following condition (B) is applied and dried
Data Source
AI summary
A solid electrolytic capacitor, including: a solid electrolytic layer; and a dielectric layer on which the solid electrolytic layer is formed. The solid electrolytic layer is formed by applying and drying a conductive-polymer solution including a conductive polymer on the dielectric layer, and the dielectric layer is formed by oxidizing a surface of an anode metal. The conductive polymer has a volume average particle size of smaller than 26 nm. A stacked aluminum electrolytic capacitor including a test solid electrolytic layer and a test dielectric layer, the test solid electrolytic layer being formed by applying and drying the conductive-polymer solution on the test dielectric layer, the test dielectric layer being formed by oxidizing a surface of aluminum having an electrical capacitance of 95 μF/cm2, has a rate of exhibited capacitance of no less than 70%.