Solid Electrolytic Capacitor Using Conductive Polymer Particles
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Solution Overview
Problem
Conventional solid electrolytic capacitors using in situ polymerized polymers suffer from high leakage current and capacitance loss, especially at high voltages and in humid environments, leading to unstable electrical properties.
Innovation Solution
A solid electrolytic capacitor design featuring a sintered porous anode body with a dielectric and a solid electrolyte composed of conductive polymer particles formed from a thiophene polymer and copolymer counterion, along with an external polymer coating, which enhances breakdown voltage, surge current handling, and capacitance recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in situ polymerized polymers are used as solid electrolyte, then low ESR and non-burning failure mode are achieved, but high leakage current and failure at high voltages occur
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by using PEDOT:PSS dispersion with specific molecular weight ratios and doping levels, achieving low leakage current while maintaining low ESR and non-burning failure mode
Solution Approach 2:
The patent creates a composite solid electrolyte structure by combining PEDOT:PSS conductive polymer with specific dopants and binders, achieving synergistic effects that reduce leakage current while maintaining the beneficial properties of in situ polymerized polymers
2Object-generated harmful factors
If PEDOT:PSS dispersions are used as solid electrolyte, then improved leakage current values are achieved, but low percentage of wet capacitance and large capacitance loss occur
Solution Approach 1:
The patent optimizes the molecular weight parameters of the PEDOT and PSS components, using a specific ratio range (0.5-5:1) to achieve both low leakage current and high capacitance retention by controlling the phase separation and percolation pathways
Solution Approach 2:
The patent creates local conductive pathways within the composite electrolyte by controlling the distribution of PEDOT-rich domains, ensuring efficient charge transport while maintaining high capacitance retention through optimized local composition
3Object-generated harmful factors
If polymer slurry-based capacitors are used, then improved leakage current values are achieved, but relatively low percentage of wet capacitance results in large capacitance loss
Solution Approach 1:
The patent develops a composite polymer slurry combining PEDOT:PSS with specific binders and fillers, creating a multi-phase structure that simultaneously achieves low leakage current and high capacitance stability through synergistic material interactions
Solution Approach 2:
The patent adjusts the slurry composition parameters including solvent content, particle size distribution, and binder ratio to optimize both leakage current reduction and capacitance stability, achieving superior performance compared to conventional slurries
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 improved electrical properties such as high breakdown voltage, low leakage current, and minimal capacitance loss, maintaining stability under various conditions including high temperatures and humidity, with a capacitance recovery of up to 100% and low equivalent series resistance.
Implementation Method 1
conductive polymer particles that contain a complex formed from a thiophene polymer and a copolymer counterion
Implementation Method 2
a dielectric that overlies the anode body
Implementation Method 3
an external polymer coating that includes conductive polymer particles
Data Source
AI summary
A solid electrolytic capacitor containing a capacitor element is provided. The capacitor element contains a sintered porous anode body, a dielectric that overlies the anode body, a solid electrolyte that overlies the dielectric that includes conductive polymer particles that contain a complex formed from a thiophene polymer and a copolymer counterion, and an external polymer coating that overlies the solid electrolyte and includes conductive polymer particles.