Solid Electrolytic Capacitor High-Viscosity Polymer Layer
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Solution Overview
Problem
Conventional solid electrolytic capacitors face issues with increased equivalent series resistance (ESR) and electrical short circuits due to low-density electroconductive polymer layers, which can lead to reduced product yield and reliability, especially when exposed to oxygen and pressure during mold forming.
Innovation Solution
A method involving a second electroconductive polymer layer with higher viscosity is applied to cover the bottom surface and side surfaces of the anode body, while leaving the leading surface open, formed using an electroconductive polymer suspension method, to prevent oxygen permeation and facilitate air release during heating, thereby enhancing reliability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a low-viscosity electroconductive polymer solution is used to form the polymer layer, then the polymer easily permeates the porous layer and forms good adhesion, but the resulting layer has low density and allows oxygen permeation leading to increased ESR
Solution Approach 1:
The patent changes the viscosity parameter of the electroconductive polymer suspension from low to high. This parameter change allows the formation of a high-density polymer layer that prevents oxygen permeation and reduces ESR increase, while still achieving adequate adhesion through the porous layer
Solution Approach 2:
The patent uses a composite approach by combining an electroconductive polymer with a suspending agent to create a high-viscosity suspension. This composite material maintains the electroconductive properties while achieving high density and oxygen barrier performance
2Reliability
If the electroconductive polymer layer is formed with high density, then oxygen permeation is prevented and ESR increase is suppressed, but the manufacturing process becomes more complex
Solution Approach 1:
The patent simplifies the high-density formation process by changing the viscosity parameter of the applied suspension rather than adding complex post-formation processing steps. The high-viscosity suspension naturally forms a dense layer during application and drying, achieving reliability improvement without significant process complexity increase
3Manufacturing precision
If the electroconductive polymer layer covers the leading surface, then complete coverage is achieved, but air and solvent trapped during heating cause delamination and increase ESR
Solution Approach 1:
The patent extracts or removes the polymer coating from the leading surface area, leaving it open while maintaining coverage on the bottom and side surfaces. This extraction prevents air and solvent entrapment during heating that would cause delamination, while still providing adequate protection and coverage where needed
Solution Approach 2:
The patent applies different coverage quality to different areas: complete coverage on the bottom and side surfaces where protection is needed, and no coverage on the leading surface where air release is critical. This local differentiation resolves the contradiction between coverage completeness and delamination prevention
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 suppresses the increase in ESR, prevents electrical short circuits, and improves product yield by ensuring high-density polymer layer formation and robustness against external pressures and oxygen exposure.
Implementation Method 1
it is pulled up, and it is then dried by heating to form an electroconductive polymer layer
Implementation Method 2
chemical oxidative polymerization method, in which the anode body (anode body element) where the dielectric layer is formed is immersed in a solution obtained by adding a monomer, a catalyst, oxidant that is a dopant and the like to a solvent, and in which it is polymerized on the surface of the dielectric layer
Data Source
AI summary
The present invention provides a solid electrolytic capacitor and a method producing the same, in which high reliability is realized and further in which the product yield is improved by suppressing the increase of ESR or the like. In the present invention, the electroconductive polymer layer includes first electroconductive polymer layer 3 and second electroconductive polymer layer 10, in which first electroconductive polymer layer 3 covers the surface of dielectric polymer 2, and the second electroconductive polymer layer is provided on a surface of first electroconductive polymer layer 3 covering the bottom surface and the side surfaces, and is provide with opening at least a part of the leading surface of first electroconductive polymer layer 3.