Conductive Polymer Dispersion for Low ESR Capacitors
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Solution Overview
Problem
Conductive polymer microparticle dispersions used in solid electrolytes for electrolytic capacitors often result in high Equivalent Series Resistance (ESR) and inadequate heat resistance due to suboptimal polymerization conditions.
Innovation Solution
A method involving the preparation of a dispersion liquid with thiophene derivatives, a polyanion, and a solvent, followed by oxidative polymerization at controlled temperatures (35° C. or less) and low dissolved oxygen concentrations (7 ppm or less) to produce conductive polythiophene microparticles, which are then used to form a solid electrolyte with improved ESR and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional oxidative polymerization is used to prepare conductive polymer microparticle dispersion, then the polymerization process is simple, but the resulting electrolytic capacitor exhibits high ESR and inadequate heat resistance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the polymerization temperature (35°C or lower) and dissolved oxygen concentration (7 ppm or lower) during oxidative polymerization. These specific parameter adjustments transform the conventional simple polymerization process into an optimized process that produces conductive polymer microparticles with superior conductivity and stability, thereby achieving low ESR and improved heat resistance in electrolytic capacitors without significantly complicating the manufacturing process
Solution Approach 2:
The patent implements an inert environment strategy by maintaining low dissolved oxygen concentration (7 ppm or lower) during the polymerization process. This controlled inert environment prevents unwanted oxidation and side reactions that would otherwise degrade the polymer quality. By creating this optimized reaction environment, the patent achieves high-performance conductive polymers with excellent heat resistance and low ESR characteristics
2Productivity
If polymerization temperature is not controlled, then the manufacturing process is faster, but the conductive polymer microparticles exhibit poor conductivity and stability
Solution Approach 1:
The patent applies parameter changes by establishing and maintaining the polymerization temperature at 35°C or lower throughout the oxidation polymerization process. This temperature control parameter is critical because it balances reaction kinetics with polymer quality. At this controlled temperature, the polymerization proceeds at an acceptable rate while simultaneously ensuring the formation of conductive polymer microparticles with high conductivity and stability, thus resolving the contradiction between productivity and manufacturing precision
3Speed
If dissolved oxygen concentration is high during polymerization, then the oxidation reaction proceeds faster, but the conductive polymer microparticles exhibit high ESR and poor heat resistance
Solution Approach 1:
The patent implements an inert environment strategy by controlling the dissolved oxygen concentration to be 7 ppm or lower during the polymerization process. This creates an optimized reaction environment where the oxidation reaction can proceed at an appropriate rate through controlled addition of oxidizing agent, while preventing excessive oxygen that would lead to polymer degradation. This controlled inert environment ensures the formation of high-quality conductive polymer microparticles with low ESR and excellent heat resistance
Solution Approach 2:
The patent applies parameter changes by precisely controlling the dissolved oxygen concentration parameter during polymerization. By maintaining this parameter at 7 ppm or lower, the patent optimizes the balance between oxidation reaction rate and polymer quality. This parameter control ensures sufficient reaction speed while preventing the formation of defective polymer structures that would cause high ESR and poor heat resistance
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 electrolytic capacitors with very low ESR and enhanced heat resistance by optimizing the polymerization conditions, resulting in conductive polymer microparticles that effectively reduce ESR and maintain performance after heat resistance testing.
Implementation Method 1
mixing the dispersion liquid with an oxidizing agent so as to oxidatively polymerize the one of thiophene and derivatives thereof
Data Source
AI summary
A dispersion liquid including one of thiophene and derivatives thereof, a polyanion, and a solvent is prepared. Then, the dispersion liquid is mixed with an oxidizing agent so as to oxidatively polymerize the one of thiophene and derivatives thereof. During the oxidative polymerization, a temperature of the dispersion liquid is 35° C. or less and a dissolved oxygen concentration of the dispersion liquid is 7 ppm or less.