Silver Vanadium Oxide Electrode for Low ESR Capacitors
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Solution Overview
Problem
High-voltage capacitors used in implantable medical devices face challenges in achieving high capacitance and low equivalent serial resistance (ESR) due to the low electrical conductivity of silver vanadium oxide, making it difficult to form a durable coating without compromising capacitance.
Innovation Solution
A method involving a metal substrate coated with a silver layer, oxidized, and then reacted with vanadium oxide in an oxygen-containing atmosphere to form a chemically bonded silver vanadium oxide layer, which is diffused into the substrate, enhancing capacitance while reducing ESR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silver vanadium oxide powder is used to coat the cathode, then capacitance is improved, but electrical conductivity deteriorates resulting in high ESR
Solution Approach 1:
The patent uses a composite coating structure consisting of a metallic silver base layer combined with a silver vanadium oxide surface layer. This composite structure leverages the high electrical conductivity of metallic silver while incorporating the high capacitance properties of silver vanadium oxide, thereby achieving both high capacitance and low ESR simultaneously
Solution Approach 2:
The patent applies different material properties to different regions of the cathode coating: the base layer uses pure metallic silver for optimal electrical conductivity, while the surface layer uses silver vanadium oxide for high capacitance. This local differentiation of material quality allows each layer to optimize its specific function without compromising the other
2Quantity of substance
If silver vanadium oxide powder is coated on metallic substrate, then capacitance is improved, but coating durability deteriorates
Solution Approach 1:
The patent applies a preliminary metallic silver coating layer to the cathode substrate before depositing the silver vanadium oxide layer. This preliminary action creates a robust foundational layer that enhances adhesion and mechanical strength, ensuring the subsequent capacitance-providing layer remains durable and resistant to degradation during device operation
3Quantity of substance
If compressed pellets of silver vanadium oxide are used, then capacitance is improved, but ESR increases due to low conductivity
Solution Approach 1:
The patent creates a composite cathode structure where highly conductive metallic silver forms the electrical conduction pathway, while silver vanadium oxide provides the capacitance function. This composite arrangement ensures that the low conductivity issue of silver vanadium oxide pellets is overcome by the conductive silver matrix, achieving low ESR while maintaining high capacitance
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 method achieves capacitance values of approximately 10 mF/cm2 or greater with reduced ESR, making the capacitor suitable for high-voltage applications in implantable medical devices and is cost-effective.
Implementation Method 1
oxidized, and then reacted with vanadium oxide in an oxygen-containing atmosphere to form a chemically bonded silver vanadium oxide layer
Implementation Method 2
reacted with vanadium oxide in an oxygen-containing atmosphere to form a chemically bonded silver vanadium oxide layer
Implementation Method 3
which is diffused into the substrate, enhancing capacitance while reducing ESR
Data Source
AI summary
Methods are provided for manufacturing an electrode. In one exemplary embodiment, the method includes the steps of contacting the silver layer with vanadium oxide, and heating the silver layer and vanadium oxide in an oxygen-containing atmosphere to form a silver vanadium oxide layer chemically bonded to the metal substrate.