Conductive Polymer Electrolyte for High-Voltage Solid Capacitors
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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, limiting their stability and effectiveness in high voltage applications.
Innovation Solution
A solid electrolytic capacitor design featuring a sintered porous anode body, a dielectric, a solid electrolyte with intrinsically conductive polymers containing repeating thiophene units, and an external polymer coating with conductive polymer particles, which enhances breakdown voltage, surge current handling, and capacitance recovery under various conditions.
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 structure parameters of the polymer by introducing specific substituents (alkyl groups, halogen atoms) at defined positions on the thiophene ring, and controls the degree of polymerization and doping level to optimize the balance between conductivity and leakage current suppression
Solution Approach 2:
The patent creates a composite solid electrolyte system combining intrinsically conductive polymer matrices with dispersed conductive polymer particles, where the matrix provides structural integrity and the particles enhance conductivity while reducing leakage current
2Ease of manufacture
If polymer slurry-based capacitors are used, then manufacturing is simplified, but only relatively low percentage of wet capacitance is achieved with large capacitance loss
Solution Approach 1:
The patent utilizes the porous structure of the anode body to enable deep penetration and uniform distribution of the polymer slurry, increasing the effective surface area for capacitance formation and improving wet capacitance percentage while maintaining manufacturing simplicity
Solution Approach 2:
The patent optimizes the slurry composition parameters including polymer concentration, solvent type, and additive content to improve wetting properties and penetration efficiency, thereby increasing capacitance recovery and reducing capacitance loss
3Ease of operation
If conventional solid electrolyte structures are used, then basic capacitor function is achieved, but instability at high voltages and high temperatures occurs
Solution Approach 1:
The patent modifies the thermal and electrical parameters of the solid electrolyte by selecting polymers with high thermal stability and optimized doping levels, enabling stable operation at elevated temperatures and voltages while maintaining basic capacitor functions
Solution Approach 2:
The patent creates regions with different polymer compositions and conductivities within the solid electrolyte layer, with more stable but less conductive regions providing thermal stability and more conductive regions maintaining electrical performance under operating conditions
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 even at high temperatures and dry conditions, with a capacitance recovery of 80% or more and low equivalent series resistance.
Implementation Method 1
The solid electrolyte includes an intrinsically conductive polymer containing repeating thiophene units
Implementation Method 2
a sintered porous anode body
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, and an external coating that overlies the solid electrolyte and includes conductive polymer particles. The solid electrolyte includes an intrinsically conductive polymer containing repeating thiophene units of a certain formula.