Laser Welded Anode Electrode for Solid Electrolytic Capacitors
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Solution Overview
Problem
Conventional solid electrolytic capacitors using liquid or solid electrolytes fail to achieve low impedance and sufficient connection strength in high-frequency regions due to damage to the dielectric oxide film during welding and inadequate adhesion during electrical connections.
Innovation Solution
A manufacturing method involving a surface-roughened flat plate-shaped metal base with an anodic oxide film, a conductive polymer solid electrolyte layer, and a cathode electrode, where a conductive paste is coated and cured, and then laser-welded to form anode electrode portions, ensuring strong and low-impedance connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode electrode portion is made small to achieve low impedance, then the impedance is reduced, but the dielectric oxide film is damaged by welding operations and connection strength becomes insufficient
Solution Approach 1:
A metal layer is introduced as an intermediary between the anode electrode portion and the external lead. This metal layer serves as a buffer that receives welding heat without damaging the dielectric oxide film, while also providing a robust connection point for external wiring. The metal layer is formed by coating conductive paste and curing it, creating a stable intermediate structure that resolves the conflict between small electrode size and welding durability.
2Ease of manufacture
If conventional welding methods are used on small anode electrode portions, then connection is achieved, but the dielectric oxide film is damaged and leakage current increases
Solution Approach 1:
The metal layer is formed in advance before the welding operation. By pre-coating the conductive paste and curing it to create the metal layer, the welding process is performed on this protective layer rather than directly on the dielectric oxide film. This preliminary formation of the metal layer prevents welding-induced damage to the oxide film, thereby reducing leakage current while maintaining ease of manufacturing through standard welding procedures.
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 method enables the production of solid electrolytic capacitors with reduced size, low impedance, and sufficient connection strength by forming metal silver layers that adhere well to the aluminum base, resulting in improved capacitance and reduced leakage current.
Implementation Method 1
irradiating a laser beam from a side, opposite to the one side where the conductive paste is coated, of the metal base to weld together the metal base and the metal layer
Implementation Method 2
an anodic oxide film formed by anodic oxidation on a surface of the metal base
Data Source
AI summary
In a method of manufacturing a solid electrolytic capacitor, at first, an anodic oxide film is formed on the surface of an aluminum base. Then, a solid electrolyte layer is formed of a conductive polymer or the like on the anodic oxide film. Then, a cathode electrode portion including a silver paste layer is formed on the solid electrolyte layer. Then, a conductive paste is coated on the anodic oxide film on one side of the aluminum base and cured, thereby forming a metal silver layer. Then, a laser beam is irradiated from the opposite side of the aluminum base to weld together the aluminum base and the metal silver layer, thereby forming an anode electrode portion.