Silver Paste Layer Composite for Solid Electrolytic Capacitor ESR Reduction
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Solution Overview
Problem
The existing silver paste layers in solid electrolytic capacitors, when thinned to reduce contact resistance, result in shorter oxygen permeation paths, leading to increased oxidation and equivalent series resistance (ESR) over time due to thermal oxidation.
Innovation Solution
Incorporating inorganic particles with a volume ratio of 15% to 50% into the silver paste layer, composed of materials like silica, glass, or graphite, alongside first silver particles with a peak size of 150 nm or less and second silver particles with a peak size of 500 nm or greater, to increase the layer thickness and lengthen the oxygen permeation path while maintaining low contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small silver particles (1-100 nm) are used to reduce contact resistance, then the contact resistance is reduced, but the layer must be thinner, shortening the oxygen permeation path
Solution Approach 1:
The composite structure combines small silver particles (1-100 nm) for conductivity with larger inorganic particles (50-500 nm) as spacers. This allows the use of small silver particles to minimize contact resistance while the inorganic particles maintain sufficient layer thickness to provide adequate oxygen permeation path length.
Solution Approach 2:
Inorganic particles serve as intermediary spacers between silver particles and the carbon layer. They maintain the necessary layer thickness and oxygen permeation path without interfering with the conductivity provided by small silver particles at contact points.
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
This configuration effectively reduces ESR by suppressing oxidation of the solid electrolyte layer and maintaining low contact resistance, even under high temperatures, thereby enhancing the reliability and performance of the solid electrolytic capacitor.
Implementation Method 1
the solid electrolyte layer is increasingly oxidized and deteriorated with time passage, or thermally-oxidized
Implementation Method 2
reduce the contact resistance between the silver paste layer and the carbon layer to thereby reduce the ESR
Data Source
AI summary
A silver paste layer constituting a collector layer in a solid electrolytic capacitor includes first silver particles having a peak particle size of 150 nm or less, second silver particles having a peak particle size of 500 nm or more, inorganic particles composed of material different from silver, and resin material. The inorganic particles are included at a volume ratio of 15% or more and 50% or less with respect to the total of the first silver particles and the second silver particles.