Solid Electrolytic Capacitor Cation Ratio for ESR Stability
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Solution Overview
Problem
Solid electrolytic capacitors with a combination of solid electrolytes and electrolytic solutions experience increased Equivalent Series Resistance (ESR) due to dedoping reactions, especially under heat stress, which affects their performance and reliability.
Innovation Solution
Incorporating a solid electrolytic capacitor design with a solid electrolyte layer and a liquid-filled air gap, where the molecular ratio of cation components relative to functional groups in the electrolyte layer is controlled to 23 or less, primarily using ammonia as a cation component, to suppress dedoping reactions and maintain low ESR even under heat stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a solid electrolyte layer is formed on the capacitor element, then the capacitor achieves small size and low ESR, but the leakage current increases due to inability to repair defective dielectric oxide film
Solution Approach 1:
The patent combines solid electrolyte layer and electrolytic solution in a hybrid configuration, where the solid electrolyte layer provides low ESR and compact size, while the electrolytic solution provides repair function for defective dielectric oxide film, thus resolving the contradiction between size reduction and reliability maintenance
2Reliability
If a hybrid-type solid electrolytic capacitor with solid electrolyte layer and electrolytic solution is used, then ESR is less affected by electrolytic solution conductivity, but dedoping reaction occurs under heat stress causing ESR to increase
Solution Approach 1:
The patent optimizes the molecular ratio of cation components to functional groups in the electrolyte layer, specifically setting it to 23 or less, and uses ammonia as the cation component to suppress dedoping reactions under heat stress, thereby maintaining ESR stability at elevated temperatures
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
This approach effectively reduces the increase in ESR after heat stress, enhancing the thermal stability and performance of the solid electrolytic capacitor by neutralizing the dopant and transferring the conductive polymer from bipolaron to polaron, thereby maintaining low ESR.
Implementation Method 1
the conductivity thereof gets worse by the dedoping reaction of the dopants and ESR of the solid electrolytic capacitor increases
Implementation Method 2
by neutralizing the dopant and transferring the conductive polymer from bipolaron to polaron
Implementation Method 3
the electrical conductivity of the conductive polymer used in the solid electrolytic capacitor is incomparably higher compared to the electrical conductivity of the electrolytic solution
Data Source
AI summary
In a solid electrolytic capacitor having an electrolyte layer consisting of a solid electrolyte layer and a liquid, the solid electrolytic capacitor, which suppresses a dedoping reaction and which ESR thereof does not keenly increase, in particular, after a loading of heat stress, is provided. In the solid electrolytic capacitor, the electrolyte layer is formed in the capacitor element which is formed by opposing an anode foil and a cathode foil. This electrolyte layer includes the solid electrolyte layer and the liquid. The solid electrolyte layer includes a conductive polymer consisting of a dopant and a conjugated polymer. The liquid is filled in air gaps in the capacitor element on which the solid electrolyte layer is formed. The electrolyte layer includes ammonia as a cation component, and a molecular ratio of the cation component relative to 1 mol of a functional group which can contribute to a doping reaction of the dopant, in the electrolyte layer is 23 or less.