Tantalum Electrode Coating With Non-Contact Micro Extrusion
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Solution Overview
Problem
Existing methods for coating tantalum electrodes in electrolytic capacitors, such as sputtering, pad printing, and piezoelectric spraying, are inefficient in material usage, limited by viscosity and temperature constraints, and prone to contamination and structural damage, making precise and high-quality coating challenging, especially for complex geometries and high-temperature applications.
Innovation Solution
A micro extruder system with a computer-assisted electric movement system is used to apply conductive coatings with precise control over viscosity, temperature, and geometry, allowing for high-precision coating of high-viscosity materials at elevated temperatures without direct contact, combined with a resistor-based forming process to prevent oxide layer formation on the counter electrode and ultrashort pulse laser marking for identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If sputtering process is used for coating, then coating can be applied on surfaces, but material usage efficiency deteriorates due to unused material distribution
Solution Approach 1:
The coating composition is applied in a self-contained manner through the micro extruder, where the material is precisely extruded only where needed on the cathode current collector, eliminating waste from unused material distribution characteristic of sputtering processes
Solution Approach 2:
The invention changes the physical state and delivery parameters of the coating material from vapor-phase deposition (sputtering) to controlled extrusion of coating composition, enabling precise material placement and significantly improving material usage efficiency
2Manufacturing precision
If pad printing process is used for coating, then coating liquid can be transferred to surface, but coating precision deteriorates due to viscosity and temperature constraints
Solution Approach 1:
The invention replaces the mechanical pad printing system with a micro extruder system that uses controlled extrusion mechanics, enabling precise coating application without the viscosity and temperature constraints that limit pad printing process parameters
Solution Approach 2:
The micro extruder acts as an intermediary device between the coating composition source and the cathode current collector, providing precise control over material delivery and enabling high manufacturing precision through controlled extrusion rather than direct pad transfer
3Manufacturing precision
If piezoelectric spraying process is used for coating, then carbon coating can be applied on cathode current collectors, but coating thickness control deteriorates due to web divergence
Solution Approach 1:
The invention extracts the coating composition delivery from the piezoelectric spraying system, using instead a micro extruder that directly extrudes the coating material without creating divergent webs, thereby maintaining precise thickness control while improving coating efficiency
Solution Approach 2:
The micro extruder provides a simple, direct coating application method that does not require complex piezoelectric systems, enabling efficient coating application with better thickness control through straightforward extrusion mechanics
4Reliability
If stainless steel electrode is used in forming bath, then forming process can be performed, but contamination occurs due to component transfer to oxide layer
Solution Approach 1:
The invention uses a tantalum counter electrode that is homogeneous in material composition with the tantalum electrode being formed, preventing contamination from dissimilar materials and ensuring oxide layer purity without complicating the forming process
Solution Approach 2:
The tantalum counter electrode creates an inert chemical environment in the forming bath, as tantalum is highly resistant to dissolution and does not release contaminating components into the oxide layer formation process, unlike stainless steel
5Temperature
If micro extruder is used for coating, then precise coating can be applied at high temperature, but direct contact causes overheating of the extruder
Solution Approach 1:
The micro extruder serves as an intermediary coating application device that maintains a controlled distance from the cathode current collector, enabling high-temperature coating while preventing direct thermal contact that would cause extruder overheating and damage
Solution Approach 2:
The invention replaces direct mechanical contact coating systems with a micro extruder system that uses controlled extrusion and maintains spatial separation, enabling temperature-independent coating application that protects the extruder from thermal damage
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
Enables efficient, precise, and contamination-free coating of tantalum electrodes with high-quality, high-thickness coatings and efficient oxide layer formation, while allowing for traceability and quality assurance through visible identifiers, enhancing manufacturing reliability and quality.
Implementation Method 1
A micro extruder system with a computer-assisted electric movement system is used to apply conductive coatings with precise control over viscosity, temperature, and geometry
Implementation Method 2
ultrashort pulse laser marking for identification
Implementation Method 3
resistor-based forming process to prevent oxide layer formation on the counter electrode
Data Source
AI summary
The invention relates to a method for manufacturing a structured cathode of an electrolytic capacitor, comprising the following steps: a) filling an electrically conductive coating composition into a micro extruder; b) moving the micro extruder with a computer-assisted electric movement system relatively to a cathode current collector to be coated, wherein the movement system allows a relative movement between the micro extruder and the cathode current collector with at least three degrees of freedom; c) applying the coating composition in a desired thickness and in a desired pattern onto the cathode current collector without contacting the cathode current collector with the micro extruder.