Sonicating Bath for Anode Foil Tunnel Cleaning
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Solution Overview
Problem
The existing electrochemical etching processes for anode foils in electrolytic capacitors face challenges in efficiently removing Polystyrenesulfonic acid (PSSA) and aluminum from the tunnels, leading to reduced capacitance gains and increased equivalent series resistance (ESR), which affects the energy density and charge efficiency of capacitors.
Innovation Solution
A method involving electrochemical etching of metal foils to form tunnels, followed by a widening process with PSSA in the solution, and subsequent sonic rinsing at frequencies less than 300 Hz to remove excess PSSA and aluminum from the tunnels, enhancing capacitance and oxide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a multiple anode stack configuration is used to increase energy density, then capacitance per unit volume increases, but equivalent series resistance (ESR) increases due to tortuous conduction paths
Solution Approach 1:
The patent applies porous anode foil with controlled pore structures to create more direct conduction paths between cathode and inner anodes. The porous structure allows charge to flow through multiple pathways simultaneously, reducing the tortuosity of the conduction path and thereby lowering ESR while maintaining high capacitance density.
Solution Approach 2:
The patent introduces a new dimensional aspect by creating three-dimensional pore networks within the anode foil structure. This allows charge transport to occur not just along the traditional planar path but through vertical and diagonal pathways as well, effectively reducing the conduction path length and ESR in the multiple anode stack configuration.
2Quantity of substance
If electrochemical etching is used to create porous anode foil, then energy density increases through increased surface area, but residual PSSA and aluminum remain in tunnels reducing capacitance gains
Solution Approach 1:
The patent employs mechanical vibration during the rinsing process to physically dislodge and remove residual PSSA and aluminum particles from the etched tunnels. The vibration creates acoustic streaming and cavitation effects that enhance the cleaning efficiency, ensuring complete removal of contaminants that would otherwise reduce capacitance gains.
Solution Approach 2:
The patent replaces conventional chemical rinsing methods with a mechanical vibration-based rinsing system. This substitution allows for more effective removal of residual materials through physical forces rather than chemical reactions, achieving cleaner tunnels and higher capacitance gains without introducing additional chemical contaminants.
3Stability of the object's composition
If tunnel widening with PSSA is performed to improve charge efficiency, then porosity increases, but excess PSSA must be removed to prevent increased ESR
Solution Approach 1:
The patent uses mechanical vibration during the rinsing process to effectively remove excess PSSA from the widened tunnels. The vibration generates acoustic cavitation and streaming effects that dislodge adhered PSSA residues without damaging the porous structure, thereby maintaining porosity while reducing ESR by removing conductive contaminants.
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 results in higher capacitance gains, improved porosity, reduced ESR, and increased delivered to stored ratio (DSR), leading to more efficient energy storage and charging in capacitors.
Implementation Method 1
The etched metal foil is removed from the widening solution and sonicated in a liquid at a frequency less than 300 Hz, where the sonicating removes excess PSSA from the plurality of tunnels
Implementation Method 2
electrochemically etching the metal foil to form a plurality of tunnels in the metal foil
Data Source
AI summary
A process and apparatus are presented for cleaning the tunnels of an electrochemically etched anode foil. The apparatus includes a tank, a fluid inlet and a fluid outlet, and one or more tranducers. The tank is designed to receive a plurality of cartridges, each of the plurality of cartridges having a reservoir and being designed to hold a metal foil. The fluid inlet and fluid outlet are coupled with at least one of the plurality of cartridges, and are designed to introduce and expel, respectively, a liquid from the reservoir within at least one of the plurality of cartridges. The one or more transducers are coupled to at least one wall of each reservoir, the one or more transducers being designed to sonicate the liquid within each reservoir at a frequency less than 300 Hz.