Cathode Surface Area Expansion via Conductive Ink Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electrolytic capacitors, particularly in implantable cardioverter defibrillators, face limitations in capacitance due to the lower surface area of cathodes compared to anodes, leading to reduced energy density and increased size, and the use of titanium nitride coatings complicates manufacturing with connection issues and higher costs.
Innovation Solution
A method using commercially available printing technologies to deposit a high surface area coating on metal foils, specifically conductive ink with nanoparticles, precisely on cathode plates, avoiding areas like tabs and cutting edges, followed by sintering to increase cathode surface area without the manufacturing complexities of titanium nitride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional aluminum foil cathodes are used in electrolytic capacitors, then the manufacturing process is simple, but the cathode surface area is insufficient compared to anodes, limiting capacitance and energy density
Solution Approach 1:
The patent applies porous materials by coating the cathode foil with a layer containing porous particles (such as metal oxides, hydroxides, or carbonaceous materials). These porous structures dramatically increase the cathode surface area, enabling it to match or exceed the anode surface area, thereby increasing capacitance and energy density without complicating the manufacturing process
Solution Approach 2:
The patent uses composite materials by combining conductive materials (such as graphite, carbon black, or metal powders) with porous materials (metal oxides, hydroxides, or carbonaceous materials) in a binder matrix. This composite structure provides both electrical conductivity and high surface area, resolving the contradiction between simple manufacturing and increased cathode surface area
2Quantity of substance
If titanium nitride coatings are applied to increase cathode surface area, then capacitance improves, but manufacturing complexity increases due to connection issues and higher costs
Solution Approach 1:
The patent replaces titanium nitride coatings with porous particle coatings (metal oxides, hydroxides, or carbonaceous materials). These porous materials achieve high surface area through their intrinsic pore structures rather than requiring complex thin-film deposition processes, thereby maintaining ease of manufacture while increasing cathode surface area and capacitance
Solution Approach 2:
The patent changes the fundamental approach from applying dense thin-film coatings (titanium nitride) to using loose porous particle coatings. This parameter change in coating structure and application method simplifies manufacturing while achieving the desired high surface area, eliminating connection issues associated with titanium nitride
3Quantity of substance
If capacitor size is reduced for implantable devices, then energy density must increase, but conventional cathode designs cannot provide sufficient capacitance per unit volume
Solution Approach 1:
The patent applies porous materials to the cathode surface, creating a three-dimensional high-surface-area structure within a thin coating layer. This enables the cathode to provide sufficient capacitance in a compact form factor, allowing reduced capacitor volume while maintaining or increasing energy density for implantable medical devices
Solution Approach 2:
The patent implements a nested structure by placing porous particles and composite materials within a binder matrix coating on the cathode foil. This nested arrangement maximizes surface area within a limited thickness, enabling high energy density in compact capacitors suitable for implantable devices
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 enhances cathode capacitance, increases energy density, simplifies production, reduces costs, and minimizes connection issues, enabling more compact high-capacity capacitors.
Implementation Method 1
A method using commercially available printing technologies to deposit a high surface area coating on metal foils, specifically conductive ink with nanoparticles
Implementation Method 2
The solvent evaporates, leaving behind a coating on the metal foil
Implementation Method 3
followed by sintering to increase cathode surface area
Data Source
AI summary
A method of processing a metal foil to produce a cathode for an electrolytic capacitor includes printing one or more layers of conductive ink on the metal foil to form a pattern of cathode plates, each of the one or more layers being a predetermined thickness, and the pattern arranged at a distance from a cathode tab and an edge of the cathode plates. The method also includes heating the deposited one or more layers of conductive ink to evaporate a solvent within the conductive ink such that conductive particles of the conductive ink remain deposited on the metal foil. The method further includes sintering the conductive particles and cutting the cathode plates from the metal foil, thereby producing the cathode plates suitable for use in the electrolytic capacitor.