Solid Electrolytic Capacitor Reducing ESR via Conductive Base
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Solution Overview
Problem
Conventional laminated solid electrolytic capacitors have high equivalent series resistance (ESR) due to insufficient conductivity in the gaps between dielectric-coated valve action metal sheets, which limits their performance in high-frequency applications and energy efficiency.
Innovation Solution
Incorporating a conductive base with higher conductivity than the solid electrolyte layer into the gaps between dielectric-coated valve action metal sheets, along with a thin cathode extraction layer and surface treatment to prevent oxidation, to enhance charge discharge and reduce ESR while maintaining or increasing capacitance per unit volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If only a solid electrolyte layer is used to fill gaps between dielectric-coated valve action metal sheets, then the structure is simple, but conductivity is insufficient resulting in high ESR
Solution Approach 1:
The patent uses a composite structure combining a solid electrolyte layer and a conductive base material within the same capacitor. The conductive base material (such as metal foil or conductive polymer) is layered together with the solid electrolyte layer to fill the gaps between dielectric-coated valve action metal sheets. This composite approach provides both the insulation properties of the solid electrolyte and the high conductivity of the conductive base, thereby reducing ESR while maintaining structural integrity.
Solution Approach 2:
The conductive base material is strategically placed in specific locations where conductivity enhancement is most needed - namely in the gaps between dielectric-coated valve action metal sheets and in contact with cathode parts. This localized application of conductive material optimizes the reduction of ESR at critical interfaces without requiring the entire structure to be made of highly conductive materials, thus balancing performance and complexity.
2Loss of energy
If a thick cathode extraction layer is provided between dielectric-coated valve action metal sheets and conductive base, then charge discharge is improved, but the thickness of the capacitor increases reducing capacitance per unit volume
Solution Approach 1:
The patent optimizes the thickness parameter of the cathode extraction layer to a specific range that balances charge discharge efficiency with compactness. By carefully controlling the thickness parameter of this layer, the invention achieves sufficient conductivity for effective charge discharge while minimizing the overall capacitor thickness, thereby increasing capacitance per unit volume.
Solution Approach 2:
The conductive base material serves as a substitute or alternative to a thick cathode extraction layer. Instead of relying solely on a thick extraction layer for conductivity, the conductive base material provides a parallel conduction path, allowing the extraction layer to be thinner while maintaining charge discharge efficiency.
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 solution significantly reduces ESR and increases capacitance per unit volume, making the solid electrolytic capacitor more efficient in high-frequency applications and energy usage.
Implementation Method 1
The conductive base(s) has (have) higher conductivity than the solid electrolyte layer, which makes it possible to reduce resistance at the cathode parts
Implementation Method 2
a dielectric coating that covers a surface of the valve action metal base at least the cathode layer forming part
Data Source
AI summary
A solid electrolytic capacitor that includes a laminated body, a solid electrolyte layer, and conductive bases. The laminated body is obtained by laminating a plurality of dielectric-coated valve action metal sheets, each of which includes a valve action metal base and a dielectric coating, and joining together the adjacent valve action metal bases. The valve action metal base has a cathode layer part, and the dielectric coating covers the surface of the valve action metal base at least the cathode layer part. The valve action metal base of at least one of the dielectric-coated valve action metal sheets further has an anode lead part. The solid electrolyte layer is a continuous layer that fills gaps between the dielectric-coated valve action metal sheets and covers the outer surface of the laminated body at the cathode layer parts, and conductive bases are provided in the solid electrolyte layer.