Solid Electrolytic Capacitor Insulating Mask for Leakage Current Reduction
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Solution Overview
Problem
The existing printing techniques for applying dispersion liquids in solid electrolytic capacitors often result in insufficient dissemination on side and end surfaces, leading to defective portions with increased leakage current (LC defects).
Innovation Solution
A solid electrolytic capacitor design that includes a valve action metal substrate with a porous layer, a dielectric layer, and an insulating material directly covering the side and end surfaces of the cathode-portion-forming portion to prevent the solid electrolyte and conductor layers from being deposited on these areas, using an insulating mask to isolate the cathode and anode portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a printing technique is used to apply dispersion liquid, then the solid electrolyte layer can be formed, but insufficient dissemination occurs on side and end surfaces leading to LC defects
Solution Approach 1:
The patent applies insulating material to the side and end surfaces of the cathode-portion-forming portion before applying the dispersion liquid. This preliminary action prevents the dispersion liquid from adhering to surfaces where it would cause defects, ensuring complete coverage only on the principal surface where the solid electrolyte layer is intended to be formed.
Solution Approach 2:
The insulating material acts as an intermediary substance between the dispersion liquid and the side/end surfaces. It prevents the dispersion liquid from directly contacting these surfaces, thereby eliminating the cause of insufficient dissemination and LC defects while allowing the dispersion liquid to properly form the solid electrolyte layer on the principal surface.
2Reliability
If insulating material is applied to cover side and end surfaces, then LC defects are reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent combines the insulating material application step with the existing cathode portion formation process. The insulating material is applied as part of the same manufacturing sequence, merging two functions (insulation and pattern formation) into a coordinated process that reduces overall complexity despite adding a material application step.
Solution Approach 2:
The insulating material serves multiple functions: it provides electrical insulation on the side and end surfaces, prevents defective adhesion of dispersion liquid, and defines the boundaries of the cathode portion-forming area. This multi-functionality justifies the additional step by consolidating multiple protective and definitional roles into a single material application.
Data Source
AI summary
A solid electrolytic capacitor that includes a capacitor device having a valve action metal substrate with a main surface, a first end surface orthogonal to the main surface and disposed in an electrode extended direction, a second end surface orthogonal to the main surface and opposite the first main surface, and a side surface orthogonal to the main surface and the first end surface, and a porous layer on the main surface, a dielectric layer on at least part of a surface of the porous layer, a solid electrolyte layer on the dielectric layer, an electric conductor layer on the solid electrolyte layer, and an insulating material directly covering one of the first and second end surfaces of the valve action metal substrate.