SOFC Interconnects with Partially Stabilized Zirconia for Thermal Shock Resistance
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Solution Overview
Problem
Solid oxide fuel cell (SOFC) stacks are prone to damage due to temperature fluctuations, leading to mechanical stress and limited thermal shock resistance, which can result in production yield reduction and increased risk of failure during operation.
Innovation Solution
The development of an interconnect for SOFCs comprising a ceramic interconnect material and partially stabilized zirconia, with the zirconia ranging from 10 to 50 vol% of the total volume, which is uniformly dispersed and sintered to enhance thermal stability and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ceramic interconnect materials are used in SOFC stacks, then the basic structural function is maintained, but the thermal shock resistance and mechanical strength are insufficient under temperature fluctuations
Solution Approach 1:
The patent applies composite materials by combining two distinct ceramic phases: a first phase (such as LST - lanthanum strontium titanate) providing structural integrity and electrical conductivity, and a second phase (partially stabilized zirconia - PSZ) providing thermal shock resistance. This composite structure allows the interconnect to simultaneously achieve both mechanical strength and thermal shock resistance that neither material could provide alone.
Solution Approach 2:
The invention implements local quality by creating a two-phase composite where each phase is strategically distributed to perform specific functions. The PSZ phase (1-50 vol%) is dispersed within the first phase matrix, with potential gradient distribution, allowing regions with higher PSZ content to handle thermal stress while regions with more first phase material maintain structural integrity and conductivity.
2Productivity
If ceramic interconnect materials are used in SOFC stacks, then the structural integrity is maintained, but the production yield is reduced due to damage from temperature fluctuations
Solution Approach 1:
The patent converts the harmful effect of thermal stress into a beneficial feature by incorporating PSZ, which undergoes controlled phase transformation during thermal cycling. This phase transformation absorbs thermal stress energy, protecting the interconnect from damage and thereby increasing production yield by reducing failure rates.
3Adaptability or versatility
If conventional interconnect materials are used, then the manufacturing process is simple, but the tolerance for temperature changes is limited
Solution Approach 1:
The invention applies parameter changes by carefully controlling the volume percentage of PSZ (1-50 vol%) and its distribution within the first phase. By adjusting this parameter, the interconnect's thermal expansion coefficient and thermal shock resistance can be optimized for specific operating conditions, while maintaining a manageable two-phase composition that doesn't excessively complicate the manufacturing process.
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 solution improves the thermal stability and mechanical strength of SOFC interconnects, reducing the risk of damage from temperature fluctuations and enhancing the reliability and yield of SOFC stacks.
Implementation Method 1
a second phase including partially stabilized zirconia
Implementation Method 2
sintering a ceramic interconnect material and partially stabilized zirconia
Data Source
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AI summary
An interconnect of a solid oxide fuel cell article is disclosed. The interconnect is disposed between a first electrode and a second electrode of the solid oxide fuel cell article. The interconnect comprises a first phase including a ceramic interconnect material and a second phase including partially stabilized zirconia. The partially stabilized zirconia may be in a range of between about 0.1 vol% and about 70 vol% of the total volume of the interconnect.