YSZ-Alumina Support Layer for SOFC Fracture Resistance
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Solution Overview
Problem
High-temperature solid oxide fuel cells (SOFCs) face structural integrity issues, particularly at fuel inlet and outlet riser openings, due to the brittle nature of ceramics, which can lead to fracture under thermal cycling and applied loads, compromising their mechanical strength and reliability.
Innovation Solution
A ceramic support layer comprising stabilized zirconia and alumina, such as yttria stabilized zirconia (YSZ) and alpha alumina, is applied around the periphery of the fuel inlet and outlet riser openings to enhance the structural integrity and mechanical strength of the SOFCs, allowing for a thinner and larger electrolyte design while reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electrolyte is made thinner to increase power density, then the power output is improved, but the structural integrity and fracture strength deteriorate
Solution Approach 1:
The patent applies composite materials by combining the electrolyte with a ceramic support layer made of stabilized zirconia and alumina. This composite structure allows the electrolyte to be thinner for higher power density while the ceramic support layer provides the necessary mechanical strength and fracture resistance, resolving the contradiction between power density and fracture strength.
2Power
If the electrolyte is made larger to increase active area, then the power output is improved, but the probability of defects and fracture risk increases
Solution Approach 1:
The ceramic support layer acts as a reinforcement that allows the electrolyte to be made larger with increased active area while maintaining reliability. The support layer compensates for the increased fracture risk associated with larger dimensions by providing additional structural integrity and reducing the probability of defect-induced failure.
Solution Approach 2:
The ceramic support layer is strategically positioned around the periphery and at critical stress points of the electrolyte, providing localized reinforcement where it is most needed. This local quality approach allows the electrolyte to be larger without uniformly increasing material usage, while specifically addressing the fracture risk at vulnerable regions.
3Strength
If a ceramic support layer is added to reinforce the electrolyte, then the fracture strength is improved, but the device complexity increases
Solution Approach 1:
The ceramic support layer is applied selectively rather than uniformly across the entire electrolyte surface. It is positioned at the periphery and around riser openings where stress concentration occurs, providing fracture strength enhancement only where needed. This reduces the overall structural complexity compared to a full ceramic reinforcement approach.
Data Source
AI summary
A solid oxide fuel cell (SOFC) that includes an anode electrode, a cathode electrode and a solid oxide electrolyte having a fuel inlet riser opening and a fuel outlet riser opening. The electrolyte is located between the anode electrode and the cathode electrode. The SOFC also includes a ceramic support layer on the electrolyte. The ceramic support is layer located around the at least one of a periphery of the electrolyte or at least partially around perimeters of the fuel inlet and fuel outlet riser openings. The ceramic support layer comprises a multi-component material comprising yttria stabilized zirconia (YSZ) and alpha alumina.