Solid Electrolytic Capacitor Electrolyte Protrusion for Leakage Control
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Solution Overview
Problem
Existing solid electrolytic capacitor elements face issues with leakage current due to thin regions near the mask layer, leading to reduced withstand voltage and reflow resistance, and increasing the thickness of the solid electrolyte layer at the periphery to mitigate this issue results in increased volume inefficiency.
Innovation Solution
A solid electrolytic capacitor element design with a protrusion in the solid electrolyte layer adjacent to the mask layer, where the thickness at the protrusion is greater than the rest, preventing conductive layer contact with the dielectric layer and reducing leakage current while maintaining a thin overall structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the solid electrolyte layer at the periphery of the substrate is increased to suppress leakage current, then the withstand voltage and reflow resistance are improved, but the volume efficiency is reduced
Solution Approach 1:
The solid electrolyte layer is designed with non-uniform thickness, featuring a protrusion with greater thickness specifically at the periphery adjacent to the mask layer, while the central region maintains a thinner profile. This local quality variation allows the peripheral region to achieve sufficient insulation for high withstand voltage and reflow resistance, while the central region contributes to reduced overall volume, thereby resolving the contradiction between reliability and volume efficiency.
2Reliability
If the thickness of the solid electrolyte layer at the periphery is increased to prevent conductive layer contact with dielectric layer, then the leakage current is reduced, but the overall thickness of the capacitor element increases
Solution Approach 1:
The solid electrolyte layer features a localized protrusion with increased thickness specifically at the peripheral region adjacent to the mask layer, where it is needed for preventing conductive layer contact with the dielectric layer and reducing leakage current. The central region maintains a thinner profile, preventing unnecessary increase in overall thickness, thus resolving the contradiction between leakage current prevention and overall thickness control.
Data Source
AI summary
A solid electrolytic capacitor element that includes: an anode including a valve acting metal substrate and having a front end face and a base end face; a dielectric layer on at least a first main face of the anode but excluding at least the base end face; a mask layer including an insulating material on the dielectric layer adjacent the base end face; and a cathode on the dielectric layer at a position closer to the front end face as compared to the mask layer, wherein the cathode includes: a solid electrolyte layer on the dielectric layer, and a conductive layer on the solid electrolyte layer, the solid electrolyte layer includes a protrusion adjacent the mask layer, and a largest thickness of the solid electrolyte layer at the protrusion is larger than a thickness of the solid electrolyte layer at a rest of the solid electrolyte layer excluding the protrusion.