Solid Electrolytic Capacitor High Specific Charge Anode
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Solution Overview
Problem
Conventional solid electrolytic capacitors with ultrahigh specific charge face challenges in impregnating small pores with a solid electrolyte, leading to poor electrical performance.
Innovation Solution
A solid electrolytic capacitor design featuring a porous anode body formed from a valve metal powder with high specific charge and low phosphorous content, combined with a dielectric layer and a solid electrolyte, enhances pore formation and electrolyte impregnation, resulting in improved electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal powders with ultrahigh specific charge (nano-scale particles) are used, then the capacitance increases, but the pores become too small for solid electrolyte impregnation
Solution Approach 1:
The patent utilizes a porous anode body structure formed from sintered valve metal powder particles. The porous structure provides adequate pore size and connectivity that allows solid electrolyte impregnation while maintaining high specific charge. The porosity is controlled through particle size selection and sintering parameters to balance capacitance and electrolyte access.
Solution Approach 2:
The patent changes critical parameters including particle size distribution, porosity, and phosphorous content to optimize both specific charge and electrolyte impregnation. By controlling the particle size range and sintering conditions, the anode achieves a pore structure that accommodates solid electrolyte while maximizing capacitance per unit mass.
2Ease of manufacture
If phosphorous content is increased to improve sintering, then the anode formation improves, but the electrical performance deteriorates
Solution Approach 1:
The patent optimizes the phosphorous content parameter to a specific range (about 10-50 ppm) that provides sufficient sintering aid while minimizing negative effects on electrical performance. This precise parameter control allows the anode to achieve adequate structural integrity without the harmful effects of excessive phosphorous on capacitance and leakage current.
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 high wet-to-dry capacitance percentage, low equivalent series resistance, and low leakage current, maintaining excellent electrical performance despite high specific charge, with specific charge ranging from 200,000 to 600,000 μF*V/g.
Implementation Method 1
The anode body is formed from a pressed and sintered valve metal powder
Implementation Method 2
anodizing the sintered anode
Implementation Method 3
applying a solid electrolyte over the dielectric layer
Data Source
AI summary
A solid electrolytic capacitor that comprises an anode that comprises a porous anode body and a dielectric layer is provided. The anode body is formed from a pressed and sintered valve metal powder having a specific charge of about 200,000 μF*V/g or more and a phosphorous content of about 150 parts per million or less. A solid electrolyte overlies the anode.