Solid Electrolytic Capacitor Insulating Region for Low Leakage Current
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Solution Overview
Problem
The challenge in forming solid electrolytic capacitors is the difficulty in highly filling small pores of the anode foil's porous part with insulating resin material, leading to increased leakage current due to conductive material penetration from the solid electrolyte layer into the insulating region.
Innovation Solution
A resin composition with an additive content rate of 3% by mass or more and a glass transition point of 230°C or more is used to fill the pores of the porous part, maintaining high dry solid content concentration while keeping viscosity low, thereby inhibiting conductive material penetration and ensuring insulation between the anode and cathode parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pores of the porous part are filled with insulating resin material to ensure insulation, then insulation between anode and cathode parts is improved, but the filling rate in small pores is insufficient leading to conductive material penetration and increased leakage current
Solution Approach 1:
The patent changes the chemical composition parameters of the resin material by incorporating specific additives (silane coupling agents, surfactants, or polymers) to modify the resin's properties. This enables the resin to effectively fill small pores while maintaining proper viscosity and curing characteristics, thereby achieving high filling rates and reliable insulation simultaneously.
Solution Approach 2:
The patent creates a composite resin material by combining insulating resin with functional additives such as silane coupling agents, surfactants, or polymers. This composite material exhibits both excellent pore-filling capability and insulation performance, resolving the contradiction between filling rate and insulation effectiveness.
2Manufacturing precision
If the content of shielding layer modifying additive is increased to improve filling performance, then the filling rate of resin material in pores is improved, but the viscosity of the resin composition increases making it difficult to fill small pores
Solution Approach 1:
The patent optimizes the content ratio of additives to base resin material. By maintaining the additive content within specific ranges (silane coupling agent: 0.1-5 wt%, surfactant: 0.1-5 wt%, polymer: 1-20 wt%), the resin achieves improved pore-filling capability while viscosity remains controllable and suitable for infiltration into small pores.
Solution Approach 2:
The patent introduces surfactants as intermediary substances that reduce surface tension and improve wetting properties of the resin. This allows the resin to penetrate small pores effectively without requiring excessive additive content that would increase viscosity, thus resolving the contradiction between filling rate and viscosity.
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 approach effectively reduces leakage current and maintains high initial capacitance with low equivalent series resistance (ESR) and tan δ, ensuring excellent capacitor performance.
Implementation Method 1
filling the pores of the porous part with a treatment liquid containing the resin composition and a solvent, and curing the resin composition
Implementation Method 2
curing the resin composition
Data Source
AI summary
A solid electrolytic capacitor element includes an anode foil having a porous part at a surface layer, a first portion including a first end and a second portion including a second end opposite the first end, a dielectric layer formed on the surface of the porous part, and a solid electrolyte layer covering at least a portion of the dielectric layer. The solid electrolytic capacitor element has an insulating region containing a cured product of a resin composition between the first and second end of the anode foil. In the insulating region, pores of the porous part are filled with the cured product. The resin composition contains an insulating resin material and an additive that modifies the insulating resin material. The content rate of the additive in the resin composition is 3% by mass or more. The glass transition point of the cured product is 230° C. or more.