Solid Electrolytic Capacitor Barrier Layer for High Withstand Voltage
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Solution Overview
Problem
Existing solid electrolytic capacitors face challenges in achieving high withstand voltage due to the formation of conductive polymer layers in defect portions, leading to decreased voltage capacity and increased equivalent series resistance (ESR), particularly when using chemical and electrolytic polymerization methods.
Innovation Solution
The introduction of a barrier layer formed by solution application between the first and second conductive polymer layers, preventing electrolytic polymerization in regions closer to the anode body, combined with chemical polymerization on the dielectric oxide film layer, ensures uniform film formation and prevents direct contact between the electrolytically polymerized layer and the anode body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If chemical polymerization and electrolytic polymerization are used to form conductive polymer layers, then the capacity is improved, but the withstand voltage decreases due to polymer layer formation in defect portions
Solution Approach 1:
The electrolyte layer is segmented into three distinct layers: a first conductive polymer layer formed by chemical polymerization, a barrier layer with conductivity, and a second conductive polymer layer formed by electrolytic polymerization. This segmentation prevents the electrolytically polymerized layer from forming in defect portions while maintaining high capacity, thereby resolving the contradiction between capacity improvement and withstand voltage maintenance.
Solution Approach 2:
The barrier layer acts as an intermediary between the first and second conductive polymer layers. It has conductivity to maintain electrical connection but prevents the electrolytically polymerized layer from forming in defect portions of the dielectric oxide film, thus protecting the withstand voltage while allowing the capacity-enhancing polymer layers to exist.
2Quantity of substance
If electrolytic polymerization is used to form conductive polymer layer, then the capacity is improved, but the ESR increases due to non-uniform film formation
Solution Approach 1:
The electrolyte layer is divided into multiple functional layers: the first conductive polymer layer formed by chemical polymerization provides a uniform base, the barrier layer prevents uncontrolled electrolytic polymerization, and the second conductive polymer layer formed by electrolytic polymerization adds capacity. This segmentation ensures uniform film formation while maintaining high capacity and low ESR.
Solution Approach 2:
The first conductive polymer layer is formed by chemical polymerization before the electrolytic polymerization step. This preliminary action creates a uniform foundation that prevents direct contact between the electrolytically polymerized layer and the anode body, ensuring uniform film formation and reducing ESR.
3Volume of moving object
If smaller capacitor design is pursued, then the size is reduced, but the withstand voltage capability decreases
Solution Approach 1:
The electrolyte layer uses a composite structure combining three different materials/layers: chemically polymerized conductive polymer, conductive barrier layer material, and electrolytically polymerized conductive polymer. This composite structure enables smaller capacitor design while maintaining high withstand voltage capability through the barrier layer's prevention of polymer formation in defect portions.
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 enhances the withstand voltage of the capacitor while maintaining a high capacity and reducing ESR, suitable for smaller capacitor designs with improved dimensional stability and uniformity.
Implementation Method 1
a first conductive polymer layer formed by chemical polymerization and in contact with the dielectric oxide film layer
Implementation Method 2
a second conductive polymer layer formed by electrolytic polymerization and formed on a side opposite to the dielectric oxide film layer with respect to the first conductive polymer layer
Implementation Method 3
the barrier layer is configured to prevent a conductive polymer layer from being formed by electrolytic polymerization in a region closer to the anode body than the barrier layer
Data Source
AI summary
A solid electrolytic capacitor has a high withstand voltage, including: a porous anode body including a valve metal and a dielectric oxide film layer formed on a surface of the valve metal; and an electrolyte layer formed on a surface of the dielectric oxide film layer. The electrolyte layer includes a first conductive polymer layer formed by chemical polymerization and in contact with the dielectric oxide film layer, a second conductive polymer layer formed by electrolytic polymerization and formed on a side opposite to the dielectric oxide film layer with respect to the first conductive polymer layer, and a barrier layer having conductivity and formed between the first conductive polymer layer and the second conductive polymer layer.10 The barrier layer is configured to prevent a conductive polymer layer from being formed by electrolytic polymerization in a region closer to the anode body than the barrier layer.