Electrolytic Capacitor Dispersion Impregnation Process
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Solution Overview
Problem
Conventional methods for manufacturing wound electrolytic capacitors are complex, prone to damage of the chemical conversion coating film, and result in high Equivalent Series Resistance (ESR) and poor voltage proofing due to the difficulty in forming an electrically conductive polymer layer without damaging the film and the risk of short-circuiting.
Innovation Solution
A method involving dispersion impregnation with electrically conductive solid particles or powder and a solvent, followed by a dry step to form an electrically conductive solid layer on the dielectric coating film, and subsequent electrolytic solution impregnation to reduce ESR and enhance voltage proofing, without the need for a washing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolytic polymerization or vapor phase polymerization method is used to form electrically conductive polymer layer in wound capacitor element, then electrically conductive polymer layer can be formed, but the process becomes operationally complicated and difficult to implement
Solution Approach 1:
The patent uses a dispersion medium as an intermediary to deliver electrically conductive polymer particles to the capacitor element. Instead of using complex electrolytic or vapor phase polymerization processes, the invention employs a simple dispersion impregnation method where polymer particles are suspended in a liquid medium that penetrates the wound capacitor element, forming the conductive layer without damaging the chemical conversion coating film
Solution Approach 2:
The patent replaces the mechanical and chemical complexity of electrolytic polymerization (requiring electrochemical cells, electrolytes, and controlled reactions) with a simple physical impregnation process. The conductive polymer is applied as pre-formed particles in dispersion, eliminating the need for complex polymerization equipment and processes while achieving the same functional result
2Reliability
If chemical oxidation polymerization method is used to form electrically conductive polymer layer, then polymerization can be achieved, but the chemical conversion coating film is damaged and has relatively large number of defects
Solution Approach 1:
The dispersion medium acts as a gentle intermediary that transports polymer particles without causing oxidative damage to the chemical conversion coating film. Unlike oxidation-based polymerization methods that attack the coating, the dispersion impregnation method uses physical penetration and deposition, preserving the integrity of the dielectric coating
Solution Approach 2:
The patent avoids the harmful oxidative effects of chemical oxidation polymerization by using pre-formed conductive polymer particles. The harmful oxidation process is replaced with a benign physical impregnation process, converting a potentially damaging chemical reaction into a safe physical deposition process that preserves coating quality
3Ease of manufacture
If soluble electrically conductive polymer is used in solvent for impregnation, then impregnation is achieved, but the polymer enters the inside of defects in chemical conversion coating film causing short-circuiting
Solution Approach 1:
The patent changes the physical state and solubility parameters of the electrically conductive polymer. Instead of using soluble polymers that can penetrate and short-circuit the coating, the invention uses insoluble polymer particles in dispersion. This parameter change ensures the polymer remains on the surface and does not migrate into defects in the chemical conversion coating film
Solution Approach 2:
The patent uses a disposable dispersion medium that evaporates or is removed after impregnation, leaving behind only the conductive polymer particles. The dispersion medium serves its purpose of delivering the polymer and then disappears, preventing any long-term presence of soluble substances that could cause short-circuiting
4Reliability
If conventional methods are used to form electrically conductive polymer layer, then polymerization can be achieved, but additional washing step is required to remove non-reacted monomer and oxidizing agent
Solution Approach 1:
The patent extracts and removes the problematic elements (monomer and oxidizing agent) from the process by using pre-formed polymer particles in dispersion. Since the polymer is already polymerized in the form of particles, there are no residual monomers or oxidizing agents to remove, eliminating the washing step entirely and improving manufacturing efficiency
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 simplifies the manufacturing process, reduces ESR, improves voltage proofing, and minimizes leakage current, while maintaining high capacitance and repairability of the dielectric coating film.
Implementation Method 1
a dispersion impregnation step of impregnating, with a dispersion containing electrically conductive solid particles or powder and a solvent, a capacitor element
Implementation Method 2
a dry step of evaporating the solvent after the dispersion impregnation step to form an electrically conductive solid layer on a surface of the dielectric coating film
Implementation Method 3
an electrolytic solution impregnation step of impregnating a gap in the electrically conductive solid layer with an electrolytic solution
Data Source
AI summary
A method of manufacturing an electrolytic capacitor including the following steps as well as an electrolytic capacitor manufactured by the method are provided. The method includes: a dispersion impregnation step of impregnating, with a dispersion containing electrically conductive solid particles or powder and a solvent, a capacitor element having an anode foil with a dielectric coating film formed thereon and an opposite cathode foil that are wound with a separator interposed therebetween; a dry step of evaporating the solvent after the dispersion impregnation step to form an electrically conductive solid layer on a surface of the dielectric coating film; and an electrolytic solution impregnation step of impregnating a gap in the electrically conductive solid layer with an electrolytic solution. Accordingly, an electrolytic capacitor that can be manufactured more easily that is excellent in voltage proofing property and that has a lower ESR and a lower leakage current is provided.