Solid Cathode Capacitor Anode Lead Attachment for Compact Packaging
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Solution Overview
Problem
The existing methods for connecting the anode lead to the anode lead frame in solid cathode electrolytic capacitors are inefficient, leading to significant volume occupancy and limitations in miniaturization, due to the need for physical separation and the challenges of attaching materials like tantalum without causing electrical shorting or damaging the capacitor.
Innovation Solution
The solution involves forming an anode lead extension from a valve metal, such as aluminum, which is attached to the anode lead by arc welding before the formation of the dielectric and cathode layers. This approach eliminates the need for a lead frame and allows for a more compact design by utilizing metallization on the encapsulation surface for electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If resistance welding is used to attach anode lead to anode lead frame, then electrical connectivity is achieved, but significant volume is occupied by the weld point separation from capacitor body
Solution Approach 1:
The patent merges the anode lead frame with the capacitor body by forming metallization directly on the capacitor body surface, eliminating the separate lead frame structure. This integration removes the need for physical separation between weld point and capacitor body, significantly reducing connection point volume while maintaining electrical connectivity through the metallization layer that serves as both the connection interface and part of the capacitor structure.
Solution Approach 2:
The patent extracts the traditional resistance welding process from the manufacturing sequence by forming metallization on the capacitor body before attaching the anode lead. This allows the anode lead to be directly connected to the metallization without requiring resistance welding, thereby eliminating the volume occupied by weld point separation while ensuring reliable electrical connectivity through the metallization interface.
2Volume of moving object
If anode node material is attached close to capacitor body to reduce space, then volume is reduced, but risk of damaging fragile capacitor body increases
Solution Approach 1:
The patent performs preliminary action by forming the metallization layer on the capacitor body surface before attaching the anode lead. This preparatory step creates a robust electrical interface that eliminates the need for subsequent resistance welding operations close to the capacitor body, thereby reducing space requirements while preventing damage to the fragile capacitor body from high-temperature welding processes.
Solution Approach 2:
The patent replaces the mechanical/thermal resistance welding process with a metallization-based electrical interface. Instead of using high-temperature resistance welding that risks damaging the capacitor body, the invention uses a metallization layer formed on the capacitor body surface that provides electrical connectivity without requiring close proximity welding, thus eliminating the damage risk while achieving compact design.
3Productivity
If resistance welding is performed before dielectric and cathode layer formation, then manufacturing sequence is simplified, but electrical shorting risk increases
Solution Approach 1:
The patent performs preliminary action by forming the metallization layer on the capacitor body surface before dielectric and cathode layer formation. This sequence ensures that the electrical interface is established on a clean, undamaged surface, eliminating the risk of electrical shorting through the dielectric and cathode layers that would occur if welding were performed earlier. The metallization serves as a stable electrical interface throughout subsequent manufacturing steps.
Solution Approach 2:
The patent extracts the resistance welding operation from the manufacturing sequence entirely by replacing it with metallization formation. This eliminates the electrical shorting risk associated with welding before dielectric and cathode layer formation, while maintaining manufacturing efficiency through the streamlined process of metallization followed by layer formation and direct anode lead attachment.
4Manufacturing precision
If laser welding is used for attachment, then precision is improved, but reflected radiation creates manufacturing problems
Solution Approach 1:
The patent replaces the laser welding process with metallization formation followed by direct attachment of the anode lead to the metallization. This substitution eliminates the reflected radiation problem inherent in laser welding while maintaining high precision through the controlled metallization process. The metallization layer provides a precise electrical interface without requiring high-energy laser processing that generates harmful reflected radiation.
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 method enhances the volumetric efficiency of the capacitor by reducing the volume occupied by the connection point, allowing for more compact designs while maintaining reliable electrical connectivity without the risks of electrical shorting.
Implementation Method 1
attached to the anode lead by arc welding
Data Source
AI summary
A solid cathode electrolytic capacitor and method of making a solid electrolytic capacitor are provided. The capacitor comprises an anode comprising an anode lead and an anode lead extension extending from the anode lead. The anode lead and anode lead extension are joined at a weld region. A dielectric is on the anode and a cathode is on the dielectric.