SOFC Electrolyte Roughness and Interconnect Perovskite Placement
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Solution Overview
Problem
High-temperature solid oxide fuel cell (SOFC) stacks experience electrolyte corrosion and cracking due to contact between fuel and a conductive perovskite material coated on interconnects, leading to catastrophic failure.
Innovation Solution
The conductive perovskite layer on interconnects is not exposed in fuel inlet and outlet risers, and the electrolyte has smoother regions adjacent to these openings to prevent contact between fuel and the perovskite material, reducing corrosion and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive perovskite layer is coated on interconnects to improve electrical conductivity, then electrical performance is improved, but electrolyte corrosion and cracking occur due to fuel contact with the perovskite material
Solution Approach 1:
The harmful conductive perovskite layer is removed from the fuel inlet riser region where it contacts fuel. The patent specifically configures the interconnect so that the perovskite coating is present on the air side but excluded from the fuel inlet opening area, thereby eliminating the source of corrosion while preserving electrical conductivity in regions where the perovskite is needed for cathode contact.
Solution Approach 2:
The perovskite layer is selectively applied only to specific regions of the interconnect - specifically the air side surface that contacts the cathode - while deliberately excluding the fuel inlet riser region. This localized coating strategy maintains electrical conductivity where required while preventing fuel-perovskite interaction that causes corrosion.
2Reliability
If the electrolyte surface is made rough to improve electrode contact, then electrical contact is improved, but corrosion resistance decreases at fuel inlet regions
Solution Approach 1:
The electrolyte surface is given different roughness characteristics in different regions: the region adjacent to the fuel inlet opening is kept smooth to prevent perovskite adhesion and corrosion, while other regions may have rougher surfaces to ensure good electrode contact. This spatial differentiation of surface properties resolves the contradiction between contact quality and corrosion resistance.
Solution Approach 2:
The electrolyte surface is segmented into functionally distinct zones: a smooth zone at the fuel inlet opening that resists corrosion, and other zones that provide optimal electrode contact. This segmentation allows each region to be optimized for its specific function without compromising the other.
Data Source
AI summary
A solid oxide fuel cell (SOFC) stack includes a plurality of SOFCs, and a plurality of interconnects, each interconnect containing a conductive perovskite layer on an air side of the interconnect. The stack in internally manifolded for fuel and the conductive perovskite layer on each interconnect is not exposed in the fuel inlet riser. The SOFC electrolyte has a smaller roughness in regions adjacent to the fuel inlet and fuel outlet openings in the electrolyte than under the cathode or anode electrodes.