Electrolytic Capacitor Resin Layer and Solvent Impregnation
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Solution Overview
Problem
Wound-type solid electrolytic capacitors face challenges with low strength due to lower conductive polymer density when using dispersion or solution impregnation methods, and are prone to electrical short-circuits from winding displacement, especially when mounted in thinner electronic devices.
Innovation Solution
The capacitors incorporate a resin layer covering the outer peripheral surface and potentially the inside of the wound body, combined with a nonaqueous solvent that contacts the dielectric film and solid electrolyte layer, enhancing strength and preventing short-circuits by improving the conductive polymer density and repairability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wound body is impregnated with a conductive polymer by using a dispersion or a solution, then the manufacturing process is simplified, but the density of the conductive polymer in the wound body becomes lower resulting in remarkably low strength of the wound body
Solution Approach 1:
The patent applies composite materials by combining the conductive polymer with a specific solvent system (acetone, ethyl methyl ketone, or butyl methyl ketone) to create a solid electrolyte layer that maintains high conductive polymer density while enabling simplified impregnation processes. This composite approach resolves the contradiction by achieving both ease of manufacture and high strength through the synergistic combination of materials.
2Length of stationary object
If the width of positive electrode foil and negative electrode foil is reduced to reduce the height of the electrolytic capacitor, then the height is reduced, but winding displacement occurs causing electrical short-circuit
Solution Approach 1:
The patent applies parameter changes by modifying the solvent composition parameters (using acetone, ethyl methyl ketone, or butyl methyl ketone) to optimize the impregnation process. This enables the use of thinner foils without causing winding displacement, as the optimized solvent system provides better penetration and stabilization of the conductive polymer in the reduced-width structure, preventing electrical short-circuits while achieving height reduction.
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
The resin layer significantly enhances the strength of the wound body and prevents electrical short-circuits, while the nonaqueous solvent improves the reliability and durability of the electrolytic capacitor by maintaining conductive polymer density and repairing damaged dielectric films.
Implementation Method 1
a nonaqueous solvent which contacts the dielectric film and the solid electrolyte layer
Implementation Method 2
the wound body is impregnated with a dispersion of a conductive polymer or a solution of a conductive polymer
Data Source
AI summary
An electrolytic capacitor includes wound body, a solid electrolyte layer, and resin layer. Wound body is formed by winding a positive electrode member having a surface with a dielectric film thereon and a negative electrode member. The solid electrolyte layer is formed by impregnating wound body with a dispersion of a conductive polymer or a solution of a conductive polymer, and then drying the dispersion or the solution with which wound body is impregnated. Resin layer covers at least a part of an outer peripheral surface of wound body.