Electrolytic Capacitor Acid-Elution Process for Low-Temperature ESR Control
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Solution Overview
Problem
Conventional hybrid electrolytic capacitors with solute components in the liquid electrolyte suffer from storage stability issues, particularly at low temperatures, leading to deteriorated characteristics and increased equivalent series resistance (ESR) due to solute precipitation and reaction with conductive polymers.
Innovation Solution
A method for producing electrolytic capacitors involving steps to form a capacitor element with a dielectric layer, impregnating with a treatment liquid containing an acid component and conductive polymer, and then with a liquid component, ensuring uneven distribution of the acid component to maintain low leak current and high withstand voltage, while controlling the acid component's amount to prevent precipitation and ESR increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solute components (supporting salts) are contained in the liquid component, then restoration function of the dielectric layer is improved, but storage stability deteriorates and solute precipitation occurs at low temperature
Solution Approach 1:
The patent extracts the harmful solute components from the liquid component and replaces them with a conductive polymer that provides similar functionality without the precipitation problem. The conductive polymer is applied to the anode foil surface to form a solid electrolyte layer, taking out the problematic supporting salts while maintaining the restoration function.
Solution Approach 2:
The patent changes the physical state of the electrolyte from liquid to solid by using a conductive polymer. This parameter change eliminates the precipitation issue that occurs with solute components in liquid electrolytes at low temperatures, while maintaining the necessary electrical and restoration functions.
2Reliability
If solute components are contained in the liquid component, then withstand voltage is improved, but equivalent series resistance (ESR) increases due to solute precipitation
Solution Approach 1:
The patent removes the solute components that cause ESR increase through precipitation and replaces them with a conductive polymer. This extraction eliminates the harmful effect of solute precipitation on ESR while maintaining the withstand voltage capability through the polymer's electrical properties.
Solution Approach 2:
The patent uses a composite structure combining the anode foil, dielectric layer, and conductive polymer layer. This composite material approach provides both the necessary withstand voltage through the dielectric layer and low ESR through the conductive polymer, avoiding the problems of solute precipitation.
3Object-generated harmful factors
If conductive polymer is used as solid electrolyte, then leak current is reduced, but low-temperature characteristics deteriorate due to solute precipitation
Solution Approach 1:
The patent extracts the problematic solute components from the liquid electrolyte and replaces them with a conductive polymer. This eliminates the precipitation that occurs at low temperatures, thereby improving low-temperature characteristics while maintaining the low leak current property of the conductive polymer.
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 enhances the restoration of the dielectric layer, maintains low leak current and high withstand voltage, and improves low-temperature characteristics without increasing ESR, thereby improving the overall performance and longevity of the electrolytic capacitor.
Implementation Method 1
the capacitor element precursor is impregnated with a treatment liquid containing an acid component, a solvent, and a conductive polymer component
Implementation Method 2
the capacitor element is formed by eluting the acid component into the liquid component
Data Source
AI summary
A method for producing an electrolytic capacitor, the electrolytic capacitor including a capacitor element including an anode body and a cathode body each having a foil shape. The anode body includes a dielectric layer on a surface of the anode body. The method includes a step of forming a capacitor element precursor by winding or stacking a separator, the anode body, and the cathode body with the separator interposed between the anode body and the cathode body, a step of impregnating the capacitor element precursor with a treatment liquid containing an acid component, a solvent, and a conductive polymer component, a step of impregnating the capacitor element precursor with a liquid component after the step of impregnating the capacitor element precursor with the treatment liquid, and a step of forming the capacitor element by eluting the acid component into the liquid component.