Solid Electrolytic Capacitor Assembly Using Moisture-Resistant Conductive Polymer
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Solution Overview
Problem
Conventional solid electrolytic capacitors using in situ polymerized intrinsically conductive polymers face issues with high leakage current and failure at high voltages, especially in humid environments, due to the oxidation of polymers like PEDOT:PSS, which decreases thermal stability.
Innovation Solution
A capacitor assembly is developed with a solid electrolyte containing intrinsically conductive polymers having specific repeating units that are less sensitive to moisture, maintaining low equivalent series resistance (ESR) and capacitance even at high humidity levels, using a sintered porous anode and dielectric formed on a tantalum or niobium base.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If PEDOT:PSS dispersion is used as solid electrolyte, then low ESR is achieved, but thermal stability decreases due to polymer oxidation in humid environments
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by using intrinsically conductive polymers with specific repeating units containing ether linkages and alkyl chains, which fundamentally alters the polymer's resistance to oxidation and moisture compared to conventional PEDOT:PSS
Solution Approach 2:
The solid electrolyte is formed as a composite material combining the intrinsically conductive polymer with specific repeating units that integrate both low ESR properties and enhanced thermal stability, creating a material that simultaneously achieves both desired characteristics
2Loss of energy
If in situ polymerized intrinsically conductive polymer is used, then low ESR is achieved, but leakage current increases and high voltage performance deteriorates
Solution Approach 1:
The patent modifies the molecular structure parameters of the conductive polymer by incorporating specific repeating units with ether linkages and controlled alkyl chain lengths, which changes the electrical properties to reduce leakage current while maintaining low ESR and improving high voltage performance
3Ease of manufacture
If conventional solid electrolyte is used, then manufacturing is simple, but performance degrades in high humidity environments
Solution Approach 1:
The patent changes the chemical composition of the solid electrolyte to use intrinsically conductive polymers with specific repeating units that are inherently resistant to moisture and oxidation, maintaining manufacturing simplicity while dramatically improving performance in high humidity environments
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 assembly exhibits excellent electrical properties with low ESR and minimal capacitance loss under high humidity conditions, maintaining performance for extended periods at elevated temperatures, with a wet-to-dry capacitance percentage of 50% or more and ESR below 150 mohms.
Implementation Method 1
The solid electrolyte includes an intrinsically conductive polymer... maintaining low equivalent series resistance (ESR)... ESR below 150 mohms
Implementation Method 2
a dielectric formed on a sintered porous body... wet-to-dry capacitance percentage of 50% or more
Data Source
AI summary
A capacitor assembly that is capable of exhibiting good properties under humid conditions. The ability to perform under such conditions is due in part to the use of an intrinsically conductive polymer in the solid electrolyte that contains repeating units having the following formula (I):wherein,R is (CH2)a—O—(CH2)b;a is from 0 to 10;b is from 1 to 18;Z is an anion; andX is a cation.Due to its unique structure, the polymer is not highly sensitive to moisture. Consequently, the resulting capacitor assembly may exhibit excellent electrical properties even when exposed to high humidity levels.