Copper-Molybdenum Composite Interconnect for SOFC Weight Reduction
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Solution Overview
Problem
Metallic interconnects used in solid oxide fuel cells are heavy, making them less suitable for aircraft applications due to weight constraints, while existing materials like stainless steel offer resistance to hydrogen embrittlement and oxidation but are not optimal in terms of weight and conductivity.
Innovation Solution
A method of fabricating an interconnect using a copper-molybdenum composite with molybdenum spheroids dispersed in a copper matrix, processed into a sheet with discontinuous, elongated reinforcement fibers, providing structural and thermal conductivity while resisting hydrogen embrittlement and oxidation, and coated with an oxidation protection layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stainless steel is used as interconnect material, then resistance to hydrogen embrittlement and oxidation is improved, but weight increases
Solution Approach 1:
The patent applies composite materials by combining copper (for conductivity and lower weight) with metal matrix reinforcement (for strength and hydrogen embrittlement resistance) and surface oxidation layers (for oxidation protection). This composite structure achieves the required reliability properties while reducing weight compared to solid stainless steel interconnects.
2Strength
If heavy gage dense materials are used for interconnects, then structural strength is improved, but weight increases making them less attractive for aircraft propulsion
Solution Approach 1:
The patent uses a composite structure with a copper matrix reinforced with metal particles or fibers. The copper provides ductility and electrical conductivity, while the metal reinforcement provides tensile strength. This allows the interconnect to achieve required structural strength with reduced weight compared to solid heavy-gage materials.
Solution Approach 2:
The patent applies different material properties to different regions: the bulk copper matrix provides conductivity and ductility, the metal reinforcement provides localized strength enhancement, and the surface oxidation layer provides corrosion protection. This local differentiation of material properties optimizes performance while minimizing weight.
3Reliability
If stainless steel alloys are used as interconnects, then resistance to oxidation is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent combines copper, which has superior electrical conductivity, with metal matrix reinforcement and surface oxidation layers. The copper matrix maintains high electrical conductivity while the composite structure and protective layers provide oxidation resistance, resolving the contradiction between conductivity and oxidation resistance that plagues stainless steel interconnects.
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 copper-molybdenum composite interconnects are lighter, offer higher strength and conductivity than stainless steel, and maintain resistance to hydrogen embrittlement and oxidation, enabling their use in fuel cells for aircraft and other applications with reduced weight and increased endurance.
Implementation Method 1
copper-molybdenum composite interconnects are lighter, offer higher strength and conductivity
Implementation Method 2
An oxidation protection layer is disposed on the air side of the metal sheet
Data Source
AI summary
A solid oxide fuel cell (SOFC) interconnect comprises a metal sheet with an air side and a fuel side in accordance with an embodiment of the present invention. The metal sheet comprises a metallic composite having a matrix. The matrix comprises a first metal. The metal sheet also comprises a plurality of discontinuous, elongated, directional reinforcement wires. The reinforcement wires comprise a second metal that is immiscible in the first metal. An oxidation protection layer is disposed on the air side of the metal sheet.