Multi-layered Conductive Polymer Coatings for High Voltage Capacitors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid electrolytic capacitors with conductive polymer technology face limitations in producing high voltage capacitors that maintain stability in high humidity and temperature environments due to issues like delamination and increased leakage current, caused by trapped gaseous bubbles in the polymer layer.
Innovation Solution
A solid electrolytic capacitor design featuring a conductive polymer coating with multiple layers, where a first layer covers only a portion of the anode body to allow bubble escape and a second layer covers the majority of the surface, minimizing delamination and enhancing electrical performance across various environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the anode body is fully immersed into a conductive slurry to form a complete polymer layer, then the coverage area is improved, but gaseous bubbles become trapped within the layer causing inhomogeneities and reducing adhesion
Solution Approach 1:
The polymer coating is divided into multiple layers with different coverage areas. The first layer covers a first area of the anode body, while the second layer covers a second area that is greater than the first area. This segmentation allows bubbles to escape during formation without compromising overall coverage or adhesion.
Solution Approach 2:
Different regions of the anode body receive different levels of polymer coverage. The first layer provides partial coverage in a first area, while the second layer provides extended coverage in a second area. This local differentiation optimizes both bubble escape pathways and adhesion properties in different regions.
2Area of stationary object
If a complete polymer layer is formed by full immersion, then surface coverage is improved, but leakage current increases due to trapped bubbles and delamination in high humidity and temperature environments
Solution Approach 1:
The polymer coating is segmented into multiple layers with progressively increasing coverage areas. This allows the formation of a complete surface coverage while maintaining pathways for bubble escape during the formation process, preventing the trapped bubbles that would otherwise increase leakage current.
Solution Approach 2:
The first layer is formed before the second layer, creating a staged formation process. This preliminary action allows bubbles to escape during the first layer formation and prevents them from being trapped when the second layer is applied, thereby reducing leakage current.
3Area of stationary object
If the polymer layer is fully applied to cover the entire anode surface, then coverage is improved, but equivalent series resistance stability deteriorates due to delamination in high temperature environments
Solution Approach 1:
The polymer coating is divided into multiple layers with different coverage areas. The first layer covers a first area and the second layer covers a second area greater than the first area. This segmentation prevents bubble entrapment and delamination, ensuring ESR stability in high temperature environments while maintaining complete coverage.
Solution Approach 2:
Different layers provide different coverage levels optimized for their specific functions. The first layer provides initial coverage with controlled bubble release, while the second layer provides extended coverage. This local quality differentiation maintains both coverage and ESR stability.
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 capacitor exhibits improved leakage current and equivalent series resistance stability, enabling reliable operation at high voltages and in humid or high-temperature environments, with reduced surface inhomogeneities and enhanced adhesion to the anode body.
Implementation Method 1
The conductive polymer coating includes a first layer and a second layer overlying the first layer. The first and second layer are formed from a dispersion of conductive polymer particles.
Implementation Method 2
a solid electrolytic capacitor that contains an anodically oxidized anode body and a conductive polymer coating overlying the anode body
Data Source
AI summary
A solid electrolytic capacitor capable of exhibiting stable electrical properties is provided. The capacitor contains an oxidized anode and a conductive polymer coating overlying the anode. The conductive polymer coating contains multiple layers formed from a dispersion of pre-polymerized conductive polymer particles. The present inventors have surprisingly discovered that capacitors formed from such conductive polymer dispersions can operate at high voltages and achieve good electrical performance at relatively high humidity and/or temperature levels and that the problem of layer delamination may be overcome by carefully controlling the conductive polymer coating configuration and the manner in which it is formed. Namely, the coating contains a first layer hat only partially covers the anode so that the gaseous bubbles generated within the first layer can escape via the uncoated portion without tearing away portions of the polymer layer, minimizing formation of surface inhomogeneities that could lead to delamination.