Solid Electrolytic Capacitor Manganese Dioxide Protrusions
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Solution Overview
Problem
Existing methods for manufacturing solid electrolytic capacitors using manganese dioxide and conductive polymers result in inferior ESR properties compared to those using only conductive polymers, with issues of adhesion and thermal stress leading to deterioration in performance.
Innovation Solution
Forming manganese dioxide protrusions in an island shape on the dielectric oxide film surface allows the conductive polymer layer to contact the film between protrusions, enhancing adhesion and preventing deterioration, while also improving capacitance through increased polymerization solution retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a manganese dioxide layer is formed to cover the conductive polymer islands on the dielectric oxide film surface, then adhesion between the conductive polymer and dielectric oxide film is improved, but ESR properties deteriorate
Solution Approach 1:
The manganese dioxide layer is segmented into protrusions with island-like cross sections rather than forming a continuous covering layer. This segmentation allows the conductive polymer layer to directly contact the dielectric oxide film in the valleys between protrusions, maintaining low ESR while the protrusions provide adhesion reinforcement.
Solution Approach 2:
The manganese dioxide protrusions are strategically positioned to provide local adhesion enhancement only where needed, rather than uniformly covering the entire surface. The protrusions have specific height and cross-sectional area ratios that optimize their adhesion function while minimizing their impact on ESR properties.
2Reliability
If a thick manganese dioxide layer (1 μm or more) is formed on the dielectric oxide film before forming the conductive polymer layer, then protection of the dielectric oxide film from oxygen damage is improved, but ESR properties deteriorate
Solution Approach 1:
The manganese dioxide layer is segmented into protrusions with controlled height and cross-sectional area, creating a porous structure that allows conductive polymer to contact the dielectric oxide film. This segmentation reduces the effective manganese dioxide thickness impacting ESR while maintaining protective function.
Solution Approach 2:
The manganese dioxide layer is designed as a porous structure with protrusions having specific height to cross-sectional area ratios. This porosity allows the conductive polymer to penetrate and contact the dielectric oxide film, maintaining low ESR while the manganese dioxide protrusions provide protection and adhesion.
3Manufacturing precision
If the conductive polymer layer is formed by immersion in aqueous suspension, then uniform coverage and sufficient thickness are achieved, but thermal stress during mounting causes damage to the manganese dioxide layer or dielectric oxide film
Solution Approach 1:
The manganese dioxide protrusions are formed before the conductive polymer layer deposition. These protrusions create mechanical interlocking features that prevent delamination during subsequent thermal stress, addressing the adhesion problem before the thermal stress event occurs.
Solution Approach 2:
The structure forms a composite system with manganese dioxide protrusions providing mechanical reinforcement and adhesion, while the conductive polymer layer provides electrical conductivity and uniform coverage. The combination of these materials with different properties creates a composite structure resistant to thermal stress.
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 method improves ESR properties, leakage current characteristics, and capacitance by ensuring better contact and adhesion between the dielectric oxide film and the conductive polymer layer, and enhances the capacitor's resistance to thermal stress.
Implementation Method 1
forming a plurality of protrusions comprising manganese dioxide on a surface of a dielectric oxide film
Implementation Method 2
a conductive polymer layer is formed on the surface of the manganese dioxide layer by chemical bonding using an oxidizing agent
Implementation Method 3
the conductive polymer layer to contact the film between protrusions, enhancing adhesion
Data Source
Figure 1~2
AI summary
A method for manufacturing a solid electrolytic capacitor with excellent ESR properties and a solid electrolytic capacitor. A method for manufacturing a solid electrolytic capacitor, wherein an anode body is obtained by forming a dielectric oxide film on the surface of a sintered body that is formed by sintering a molded body formed of a valve acting metal powder or on the surface of a roughened valve acting metal foil, and a solid electrolyte layer is formed on the surface of the anode body. This method for manufacturing a solid electrolytic capacitor is characterized by steps for forming a solid electrolyte layer including a protrusion forming process where protrusions formed of manganese dioxide and having an average diameter of 10∼102 nm are formed on the surface of the dielectric oxide coating film so that the protrusions are scattered about like islands and the surface coverage is 1 ∼ 20% and a conductive polymer layer forming process where a conductive polymer layer is formed on the surfaces of the projections and the dielectric oxide coating film.