Annular Packing Material With Thermal Expansion for SOFC Sealing
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Solution Overview
Problem
Conventional sealing materials for fuel-cell cell stacks, such as those containing vermiculite, lose elasticity and sealing ability when exposed to high temperatures due to hardening, leading to potential gas leaks.
Innovation Solution
An annular packing material composed of a thermally expandable metal material with an insulating metal oxide layer, which maintains contact pressure and insulating properties even at high temperatures, preventing hardening and ensuring long-term sealing efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If inorganic materials such as vermiculite are used as sealing materials, then thermal resistance is improved, but the sealing material hardens at high temperatures and loses elasticity
Solution Approach 1:
The sealing material uses a composite structure combining a metal base material with a metal oxide coating layer. The metal provides elasticity and thermal expansion properties, while the metal oxide coating provides thermal resistance and insulation, creating a material that maintains both sealing ability and temperature resistance.
Solution Approach 2:
The invention utilizes the thermal expansion parameter of the metal base material to maintain sealing pressure at high temperatures. As temperature increases, the metal expands to compensate for gaps and maintain contact pressure, preventing the hardening and elasticity loss that occurs with conventional inorganic materials.
2Stress or pressure
If the sealing material is exposed to high temperatures repeatedly, then the metal material expands to increase contact pressure, but the material may harden and lose elasticity over time
Solution Approach 1:
The metal base material is specifically selected and designed to utilize thermal expansion at high temperatures to increase and maintain contact pressure. This expansion compensates for thermal gaps and ensures continuous sealing effectiveness throughout the service life of the fuel cell stack.
Solution Approach 2:
The metal oxide coating is applied selectively to the sealing surface to provide localized thermal resistance and chemical stability where needed, while the bulk metal material maintains its elasticity and thermal expansion properties. This localized application of different material properties optimizes both durability and sealing performance.
3Ease of manufacture
If conventional sealing materials are used, then manufacturing is simple, but the sealing ability decreases due to hardening at high temperatures
Solution Approach 1:
The metal oxide coating layer thickness and composition are optimized to provide adequate thermal resistance while maintaining manufacturing feasibility. The coating process and material selection balance performance requirements with manufacturing complexity to achieve reliable high-temperature sealing.
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 annular packing material effectively maintains high sealing and insulating properties across temperature changes, including high-temperature environments, by utilizing thermal expansion to increase contact pressure and prevent hardening of the metal material, thus ensuring reliable gas containment.
Implementation Method 1
a metal material made of a thermally expandable member that thermally expands... when the annular packing material is exposed to high temperatures, the contact pressure increases due to the expansion tension of the metal material
Implementation Method 2
an insulating metal oxide layer... the insulating properties are maintained due to the metal oxide layer
Data Source
AI summary
The present invention includes metal materials 42a and 52a made of thermally expandable members that thermally expand, and insulating metal oxide layers 42b and 52b. The metal materials 42a and 52a and the metal oxide layers 42b and 52b formed in an annular shape have through holes 42c and 52c thereinside.