Composite Fuse Element Overlay for Lower-Cost Arc Interruption
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Solution Overview
Problem
Traditional power fuses constructed with pure silver are costly, and substituting copper reduces critical performance areas, necessitating a cost-effective solution that maintains silver's performance while minimizing copper-related issues.
Innovation Solution
A silver and copper composite overlay fuse element is produced using metal stamping and ultrasonic welding processes, where copper strain absorbing features are combined with silver arc interrupting features, forming a weld joint to create an overlay, reducing silver usage and fabrication costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure silver is used for fuse element construction, then performance (temperature response, time-current melting behavior, arc suppression, life cycle fatigue resistance) is improved, but fabrication cost increases significantly
Solution Approach 1:
The patent applies composite materials by creating a fuse element with a copper base material and a silver overlay layer. The copper provides structural integrity and cost-effectiveness, while the silver overlay maintains the critical performance characteristics. This composite structure resolves the contradiction by combining the advantages of both materials - the low cost and structural strength of copper with the superior electrical and thermal properties of silver.
Solution Approach 2:
The patent applies local quality by concentrating the silver material only in specific areas where it is most needed - the overlay layer on the surface of the copper fuse element. This localized application of silver ensures that the critical performance functions (arc suppression, temperature response) are maintained in the areas where they are most important, while reducing overall silver usage and cost in less critical areas.
2Ease of manufacture
If copper is substituted for silver in fuse elements, then fabrication cost is reduced, but critical performance areas (temperature response, arc suppression) deteriorate
Solution Approach 1:
The patent uses composite materials to combine copper and silver in a way that leverages the strengths of each material. The copper base provides structural support and cost-effectiveness, while the silver overlay restores the critical performance characteristics that would be lost with pure copper construction. This composite approach directly addresses the performance deterioration issue while maintaining cost benefits.
Solution Approach 2:
The patent applies parameter changes by modifying the physical and chemical properties of the fuse element through the silver overlay. The overlay changes the surface characteristics, thermal conductivity, and electrical properties in the critical areas, thereby improving temperature response and arc suppression performance compared to pure copper construction.
3Reliability
If braised composite material is used to fabricate fuse elements, then silver performance is preserved, but fabrication cost remains high and process complexity increases
Solution Approach 1:
The patent replaces the traditional braising process (a thermal joining process requiring high temperatures and specialized equipment) with electroplating or electroless plating processes. These alternative methods deposit silver onto the copper substrate using electrical or chemical mechanisms, achieving the same composite structure with simpler, more cost-effective, and more controllable fabrication processes.
Solution Approach 2:
The patent changes the fabrication parameters from high-temperature braising to lower-temperature plating processes. This parameter change maintains the silver overlay structure and performance characteristics while dramatically simplifying the fabrication process, reducing equipment requirements, and lowering overall fabrication costs.
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 reduces fabrication costs associated with pure silver while preserving performance by increasing copper content and using efficient metal stamping and ultrasonic welding processes, overcoming traditional fabrication challenges.
Implementation Method 1
The plurality of arc interrupting weak spot features (43) constructed of a silver metal portion and a copper metal portion wherein a weld joint forms an overlay of the silver and copper metal portions on each of the plurality of arc interrupting weak spot features (43)
Data Source
AI summary
The disclosed concept relates generally to overlay composite fuse elements, materials for their construction that include copper and silver metals, and methods of production and fabrication using metal stamping and ultrasonic welding processes. In certain embodiments, a composite overlay fuse element includes a composite metal material 37 constructed of silver and copper metals, which includes a plurality of strain absorbing bend features 39 constructed of copper metal, and a plurality of arc interrupting weak spot features 43 constructed of a silver metal portion and a copper metal portion. The silver and copper metal portions on each of the plurality of arc interrupting weak spot features 43 are connected by a weld joint surface 45 that is structured to form an overlay of the silver and copper metal portions.