High-Temperature Solid Electrolytic Capacitor Cathode
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Solution Overview
Problem
Conventional solid electrolytic capacitors are sensitive to high temperatures, as contaminant gases can be generated from carbon-based binders in the cathode coating, leading to performance degradation.
Innovation Solution
A capacitor design featuring a noble metal layer and a sintered metal particle layer in the cathode coating, which remains mechanically stable at high temperatures, minimizing detachment and maintaining electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon-based binders are used in the cathode coating, then ease of manufacture is improved, but harmful factors are generated at high temperatures
Solution Approach 1:
The patent removes carbon-based binders from the cathode coating formulation, extracting the harmful component that generates contaminant gases at high temperatures. The cathode coating is formed using conductive metal particles and binders that do not decompose to produce harmful gases, thereby eliminating the source of contamination while maintaining manufacturing feasibility.
Solution Approach 2:
The invention changes the chemical composition parameters of the cathode coating by substituting carbon-based binders with alternative binder materials that are thermally stable and do not generate contaminant gases. This parameter change allows the coating to maintain its binding function without producing harmful emissions at elevated temperatures.
2Ease of manufacture
If conventional cathode coating is used, then ease of manufacture is improved, but reliability deteriorates at high temperatures
Solution Approach 1:
The patent employs a composite cathode coating structure consisting of conductive metal particles (such as silver, aluminum, or copper particles) combined with thermally stable binder materials. This composite formulation provides both electrical conductivity and thermal stability, ensuring reliable capacitor performance at high temperatures while maintaining ease of manufacture through conventional coating processes.
Solution Approach 2:
The invention modifies the compositional parameters of the cathode coating by selecting materials with appropriate thermal stability characteristics. The coating includes metal particles with controlled size distributions and binder materials formulated to remain stable at operating temperatures, thereby improving reliability without complicating the manufacturing process.
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 excellent electrical properties, including high capacitance and low equivalence series resistance, even at temperatures up to 230°C, with stable performance over extended periods.
Implementation Method 1
pressing a metal powder (e.g., tantalum) around a metal lead wire, sintering the pressed part
Implementation Method 2
anodizing the sintered anode
Implementation Method 3
applying a solid electrolyte (e.g., manganese dioxide)
Implementation Method 4
sintering the metal particles to form a sintered metal particle layer
Data Source
AI summary
A capacitor that comprises a capacitor element that includes an anode that contains a dielectric formed on a sintered porous body, a solid electrolyte overlying the anode, and a cathode coating is provided. The cathode coating includes a noble metal layer (e.g., gold) overlying the solid electrolyte and a layer overlying the noble metal layer that includes sintered metal particles (e.g., silver particles).