Solid Electrolytic Capacitor with Segmented Polymer and Manganese Dioxide Electrolyte
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Solution Overview
Problem
Conventional solid electrolytic capacitors using manganese dioxide exhibit high equivalent series resistance (ESR) due to low conductivity, and forming a conductive polymer layer does not sufficiently reduce ESR.
Innovation Solution
A solid electrolytic capacitor design featuring a conductive polymer layer in contact with one portion of the dielectric layer surface and a manganese dioxide layer in contact with the remaining portion, with the conductive polymer layer formed like islands and the manganese dioxide layer covering both the polymer and dielectric surfaces, optimizing the coating ratio and thickness for improved conductivity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only manganese dioxide layer is formed on the dielectric layer surface, then adhesion to dielectric layer is improved, but ESR becomes high due to low conductivity
Solution Approach 1:
The electrolyte layer is segmented into two distinct materials: a conductive polymer layer and a manganese dioxide layer. Each layer is formed on different portions of the dielectric layer surface, with the conductive polymer addressing ESR and manganese dioxide addressing adhesion, thereby resolving the contradiction between these two requirements.
Solution Approach 2:
Different regions of the dielectric layer surface are assigned different electrolyte materials based on their specific functional requirements. The conductive polymer is placed in regions where low ESR is critical, while manganese dioxide is placed in regions where adhesion is critical, optimizing local performance throughout the structure.
2Object-generated harmful factors
If only conductive polymer layer is formed on the dielectric layer surface, then ESR is reduced due to high conductivity, but storage characteristics deteriorate due to poor adhesion
Solution Approach 1:
The electrolyte layer is divided into two functional segments: conductive polymer for ESR reduction and manganese dioxide for adhesion improvement. This segmentation allows each material to perform its optimal function without compromising the other, resolving the contradiction between ESR and storage characteristics.
Solution Approach 2:
The electrolyte layer is formed as a composite structure combining conductive polymer and manganese dioxide. This composite approach leverages the high conductivity of the polymer and the excellent adhesion of manganese dioxide, achieving both low ESR and good storage characteristics simultaneously.
3Object-generated harmful factors
If coating ratio of conductive polymer layer is increased, then ESR is reduced, but contact surface area of manganese dioxide layer decreases and storage characteristics lower
Solution Approach 1:
The coating ratio of the conductive polymer layer is optimized to a specific range (3-70% of the dielectric layer surface area) to balance ESR reduction with maintaining sufficient manganese dioxide contact area for good storage characteristics. This parameter optimization resolves the contradiction by finding the optimal middle ground.
4Reliability
If coating ratio of conductive polymer layer is decreased, then storage characteristics are improved, but ESR reduction effect becomes insufficient
Solution Approach 1:
The coating ratio of the conductive polymer layer is set to a minimum of 3% of the dielectric layer surface area to ensure sufficient ESR reduction effect while maintaining adequate space for manganese dioxide layer formation. This parameter setting resolves the contradiction by establishing the optimal lower bound.
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 significantly reduces ESR and enhances storage characteristics, achieving a balance between low ESR and high capacity retention ratio by adjusting the conductive polymer layer's coating ratio and manganese dioxide layer's thickness.
Implementation Method 1
The conductivity of a conductive polymer (102 (S/cm)) is higher than the conductivity of manganese dioxide (10−1 (S/cm)). In the invention, since the conductive polymer layer with such a high conductivity is formed so as to have contact with a portion of the region on the dielectric layer surface, as compared with that in the case where only the manganese dioxide layer is formed on the dielectric layer surface, the ESR can be reduced.
Implementation Method 2
Since the manganese dioxide layer is excellent in adhesiveness to the dielectric layer as compared with the conductive polymer layer, formation of the manganese dioxide layer so as to have contact with the other portion of the region on the dielectric layer surface can improve storage characteristics as compared with that in the case where only the conductive polymer layer is formed on the dielectric layer surface.
Data Source
AI summary
The present invention relates to a solid electrolytic capacitor provided with a anode made of a metal or an alloy having valve action, a dielectric layer formed on the anode, and an electrolyte layer consisting of a conductive polymer layer formed so as to have contact with a portion of the region on the dielectric layer surface and a manganese dioxide layer formed so as to have contact with the other portion of the region on the dielectric layer surface.