SOFC Seal Design Resolving Compression and Insulation Trade-offs
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Solution Overview
Problem
Existing electrochemical devices, such as SOFC and SOEC, face challenges with seal quality, requiring high compressive forces for metal gaskets, which can lead to inefficiencies, short-circuits, and reduced durability due to inadequate sealing and expansion coefficient mismatches, especially with glass gaskets that are prone to deformation under pressure.
Innovation Solution
A sealed gasket design featuring a glass or vitroceramic sealing means supported by an electrically insulating porous material frame with machined channels and tabs, allowing precise positioning and adherence to metal spans, effectively sealing gas leaks and preventing oxidation, while maintaining electrical insulation and withstanding high pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal gaskets are used to achieve sealing, then sealing effectiveness is improved, but compressive forces required increase and electrical insulation is compromised
Solution Approach 1:
The patent uses a composite structure combining a porous support (providing mechanical strength and compression resistance) with a sealing layer (providing sealing effectiveness). This composite approach allows the sealing layer to perform its sealing function without requiring the entire gasket structure to withstand high compressive forces, thus resolving the contradiction between sealing effectiveness and compressive force requirements.
Solution Approach 2:
The porous support acts as an intermediary between the sealing layer and the metal spans, providing mechanical support and distributing compressive forces. This intermediary structure allows the sealing layer to focus on sealing effectiveness while the porous support handles the mechanical loading, resolving the contradiction between sealing performance and force requirements.
2Reliability
If glass gaskets are used to provide electrical insulation, then electrical insulation is improved, but resistance to deformation under pressure deteriorates
Solution Approach 1:
The patent creates a composite gasket where the porous support provides mechanical strength and resistance to deformation, while the sealing layer (which can be glass or vitroceramic) provides electrical insulation and sealing. This composite structure resolves the contradiction by assigning different functions to different materials within the same component.
Solution Approach 2:
The patent applies different material properties to different regions of the gasket: the porous support region provides mechanical strength and compression resistance, while the sealing layer region provides electrical insulation and sealing. This local differentiation of material properties resolves the contradiction between electrical insulation and deformation resistance.
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 provides an efficient, durable, and leak-proof seal for large surface area cells at high temperatures, maintaining performance and extending the lifespan of electrochemical devices under pressures up to 50,000 Pa with improved resistance and reduced risk of short-circuits.
Implementation Method 1
a heating step to melt the sealing means and set it into place
Implementation Method 2
an electrically insulating porous material frame with machined channels
Data Source
AI summary
A seal is mountable in contact with two metal carriers of an electrochemical device, in particular a solid oxide fuel cell (SOFC) or a high-temperature solid oxide electrolyser cell (SOEC) for electrolysis of water vapour. This seal comprises a means for making the seal impermeable, comprising at least one vitreous material; and an electrically insulating supporting means that supports the impermeable means and that has two parallel main faces, an external peripheral edge and an internal peripheral edge, the seal being able to be mounted against these carriers via these main faces, which are covered with the impermeable means. The impermeable means partitions the supporting means between these internal and external edges while extending continuously from one of the main faces to the other through the supporting means, so that the impermeable means directly connects these carriers to each other.