Composite Electrode for High Voltage Capacitor Leakage Reduction
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Solution Overview
Problem
High voltage conductive polymer capacitors suffer from poor reliability due to inhomogeneous aluminium oxide layers, cracks at grain boundaries, poor film properties, and incomplete coverage, leading to high leakage currents and reduced yield.
Innovation Solution
A composite electrode with a metal oxide dielectric layer and a nitrogen-containing polymer dielectric layer is used, where the polymer dielectric layer is disposed on the metal oxide dielectric layer to enhance insulating properties and coverage, reducing leakage currents and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal oxide dielectric layer is used, then the capacitor can achieve high voltage operation, but the aluminium oxide layer becomes inhomogeneous and cracks are generated at grain boundaries causing leakage current
Solution Approach 1:
The patent applies composite materials by combining metal oxide dielectric layer with polymer dielectric layer to create a composite dielectric layer. This composite structure leverages the high voltage capability of metal oxide while the polymer layer fills cracks and provides uniform insulation, thereby reducing leakage current and improving reliability.
2Reliability
If conductive polymer is used as solid electrolyte, then the capacitor exhibits adequate insulating property and safety, but the polymer has poor film properties and is highly brittle causing deformation and breakdown
Solution Approach 1:
The patent creates a composite dielectric layer combining metal oxide and polymer materials. The metal oxide provides structural strength and film integrity, while the polymer provides insulating properties. This composite approach allows the dielectric layer to maintain both mechanical strength and electrical insulation performance.
3Reliability
If conductive polymer is used as solid electrolyte, then the capacitor is safe and free of explosion, but the polymer has poor film forming property and cannot completely cover the surface of the oxide layer resulting in high leakage current
Solution Approach 1:
The composite dielectric layer combines metal oxide and polymer where the polymer component provides excellent coverage properties that allow complete surface coverage, while the metal oxide maintains the safety characteristics. The synergistic combination ensures both complete coverage and safety.
4Temperature
If aluminium oxide layer is formed by anodization, then the capacitor can operate at high voltage, but the layer is inhomogeneous and cracks are easily generated at grain boundaries
Solution Approach 1:
The patent forms a composite dielectric layer where the metal oxide layer (formed by anodization) provides high voltage capability while the polymer dielectric layer is deposited over it to fill inhomogeneities and cracks. This composite structure maintains the high voltage operation capability while achieving compositional homogeneity and crack-free structure.
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 composite electrode effectively reduces leakage currents and enhances the yield of high voltage capacitors by improving the insulating and coverage properties of the metal oxide dielectric layer, resulting in lower impedance and higher reliability.
Implementation Method 1
the polymer dielectric layer includes a nitrogen-containing polymer and is disposed on a surface of the metal oxide dielectric layer
Data Source
AI summary
Provided is a composite electrode including a metal layer and a composite dielectric layer. The composite dielectric layer includes a metal oxide dielectric layer and a polymer dielectric layer. The composite dielectric layer overlays the metal layer. The polymer dielectric layer includes a nitrogen-containing polymer and overlays the metal oxide dielectric layer. An electrolytic capacitor is also provided. The electrolytic capacitor has a polymer dielectric layer made of a nitrogen-containing polymer, and such polymer dielectric layer is beneficial to increase the insulating property of the metal oxide dielectric layer and the coverage property of the conductive polymer. Thereby, the conventional leakage current can be significantly reduced and the yield can be improved.