Electrolytic Capacitor Solvent Composition for Heat Resistance
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Solution Overview
Problem
Conventional electrolytic capacitors face issues with high Equivalent Series Resistance (ESR) and leakage current due to solvent permeation through the sealing member, leading to oxidation deterioration of the solid electrolyte layer, especially under high temperature conditions, where the composition of the solvent has not been adequately studied for its impact on evaporation and heat resistance.
Innovation Solution
An electrolytic capacitor design incorporating a solvent composition with a glycol compound at 10% by mass or more and a sulfone compound at 30% by mass or more, which suppresses solvent permeation and oxidation deterioration, maintaining low ESR and improving heat resistance by enhancing the orientation and crystallinity of the π-conjugated conductive polymer and increasing the dissociability of the solute for dielectric layer restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solvents are used in the electrolyte solution, then the capacitor can operate, but solvent permeation through the sealing member occurs leading to oxidation deterioration of the solid electrolyte layer and high ESR
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent by specifying precise proportions: glycol compound (10-60% by mass), sulfone compound (30-80% by mass), and lactone compound (5-30% by mass). This parameter optimization suppresses solvent permeation through the sealing member and prevents oxidation deterioration of the solid electrolyte layer, thereby improving heat resistance and reducing ESR.
Solution Approach 2:
The patent uses a composite solvent system combining three different types of compounds (glycol, sulfone, and lactone) rather than a single solvent. This composite electrolyte solution leverages the complementary properties of each component: glycol for low temperature performance, sulfone for high temperature stability and low permeation, and lactone for overall performance balance, effectively preventing solvent permeation and oxidation.
2Temperature
If the solid electrolyte layer is exposed to high temperature, then the capacitor operates in hot environments, but oxidation deterioration occurs causing increased ESR
Solution Approach 1:
The patent optimizes the solvent composition parameters to specifically address high-temperature stability. The sulfone compound proportion is set at 30-80% by mass due to its excellent high-temperature properties and low permeation characteristics. This parameter change ensures the solvent maintains its protective function at elevated temperatures, preventing oxidation deterioration of the solid electrolyte layer and maintaining low ESR.
Solution Approach 2:
The patent converts the potential harm of high temperature exposure into a benefit by selecting solvent components that become more effective at preventing oxidation under thermal stress. The sulfone compound, in particular, demonstrates enhanced stability and protective capabilities at high temperatures, turning the harsh thermal environment into a condition where the optimized solvent composition provides superior protection against oxidation deterioration.
3Reliability
If the electrolyte solution composition is not optimized, then the capacitor can be manufactured simply, but high leakage current and high ESR occur
Solution Approach 1:
The patent establishes specific parameter ranges for the electrolyte solution composition: glycol compound (10-60% by mass), sulfone compound (30-80% by mass), and lactone compound (5-30% by mass). These parameter specifications balance performance requirements with manufacturing feasibility, ensuring low leakage current and ESR while providing clear manufacturing guidelines that do not excessively complicate the production process.
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 proposed solution effectively reduces leakage current and maintains low ESR while providing excellent heat resistance by minimizing solvent evaporation and oxidation deterioration, even under high temperature exposure, thereby enhancing the capacitor's performance and longevity.
Implementation Method 1
solvent permeation through the sealing member, leading to oxidation deterioration of the solid electrolyte layer
Implementation Method 2
enhancing the orientation and crystallinity of the π-conjugated conductive polymer
Implementation Method 3
increasing the dissociability of the solute for dielectric layer restoration
Implementation Method 4
oxidation deterioration of the solid electrolyte layer, especially under high temperature conditions
Data Source
AI summary
An electrolytic capacitor includes an anode body having a dielectric layer; a solid electrolyte layer in contact with the dielectric layer of the anode body; and an electrolyte solution. The solid electrolyte layer includes a π-conjugated conductive polymer. The electrolyte solution contains a solvent and a solute, and the solvent contains a glycol compound and a sulfone compound. A proportion of the glycol compound contained in the solvent is 10% by mass or more. A proportion of the sulfone compound contained in the solvent is 30% by mass or more. A total proportion of the glycol compound and the sulfone compound contained in the solvent is 70% by mass or more.