Continuous Insulating Film for Aluminum Capacitor Stack Edges
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Solution Overview
Problem
Stacked electrolytic capacitors face challenges due to alignment holes that reduce surface area, create gas-rich regions, and increase complexity, leading to potential device failure, and the manual taping process for insulation is labor-intensive and prone to errors.
Innovation Solution
A continuous electrically insulating film is applied over the edges and peripheral portions of the capacitor stack, using either a shrinkable or elastic material that conforms to the shape without adhesive, eliminating the need for manual taping and reducing the risk of damage during application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alignment holes are used in separators, anodes, and cathodes for precision physical alignment during assembly, then manufacturing precision is improved, but the surface area of each anode and cathode is reduced, requiring compensation in the number of components or overall physical outline
Solution Approach 1:
The alignment holes are extracted and replaced by alignment features on the stacking fixtures. The fixtures include protrusions that engage with recesses in the components, transferring the alignment function from the components themselves to the fixtures, thereby preserving the full surface area of anodes and cathodes.
Solution Approach 2:
The stacking fixtures serve as intermediaries between the components. The fixtures include alignment protrusions that mate with alignment recesses, providing precise positioning without requiring holes in the functional components. This intermediary mechanism enables accurate alignment while maintaining component integrity and surface area.
2Manufacturing precision
If alignment holes are created in the components, then assembly alignment is improved, but isolated cavities are created that can lead to gas rich, electrolyte starved regions
Solution Approach 1:
The alignment holes are removed from the functional components and their alignment function is transferred to the stacking fixtures. This eliminates the creation of isolated cavities within the capacitor structure that could trap gas and create electrolyte-starved regions, thereby improving reliability without sacrificing alignment capability.
3Quantity of substance
If more material is removed from anode foil to create greater surface area, then capacitance is increased, but the foil becomes more difficult to punch without creating cracks and particles
Solution Approach 1:
The alignment features (recesses) are pre-formed in the anode foil along with the etching process, before the punching operation. This preliminary preparation of alignment recesses allows the subsequent punching to proceed more smoothly with reduced risk of cracks and particles, as the material has already been softened or prepared in the critical zones.
4Reliability
If manual taping process is used to insulate edge portions of the capacitor stack, then insulation is achieved, but the process is labor intensive, difficult to reproduce, and slow
Solution Approach 1:
The edge portions of the capacitor stack are provided with self-aligned insulation features through the stacking process. The insulation arises automatically from the precise positioning and layering of components during automated stacking, eliminating the need for separate manual taping operations. The structure insulates itself through proper assembly geometry.
Solution Approach 2:
The manual mechanical taping process is replaced with an automated stacking and insulation system. The insulation is achieved through automated placement of insulating layers or structures during the stacking process, substituting manual labor with automated mechanical systems that are faster, more consistent, and easier to reproduce.
5Reliability
If manual taping process is used for insulation, then insulation coverage is achieved, but the process is prone to errors and can damage the stack
Solution Approach 1:
The capacitor stack structure provides self-aligned insulation through its geometric configuration and automated assembly process. Insulating layers are automatically positioned during stacking, eliminating the need for manual taping operations that are prone to errors and potential damage. The structure ensures proper insulation coverage through its design and assembly process.
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 solution enhances the reliability and efficiency of capacitor manufacturing by ensuring precise alignment and insulation without damaging the stack, reducing manufacturing costs and improving the long-term reliability of the capacitors.
Implementation Method 1
arranging a continuous shrinkable insulating film around a capacitor stack... and shrinking the insulating film to form a continuous shrunken film
Implementation Method 2
a dielectric material disposed on a surface of each of the conductive anodes
Data Source
AI summary
A device includes an electrode stack including a plurality of conductive anodes, a plurality of conductive cathodes, a plurality of separators arranged between the conductive anodes and the conductive cathodes, and a dielectric material disposed on a surface of each of the conductive anodes. The stack has a top surface, a bottom surface, and an edge extending between the top surface and the bottom surface. A continuous electrically insulating film overlies the edge, peripheral portions of the top surface and peripheral portions of the bottom surface so that a central portion of the top surface and a central portion of the bottom surface are exposed. An electrolyte is disposed between the conductive anodes and the conductive cathodes.