SOFC Seal Configuration for Gas Conversion and Stress Reduction
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Solution Overview
Problem
Existing high-temperature water electrolysis (HTE) and solid oxide fuel cell (SOFC) systems face challenges in achieving high gas conversion rates and minimizing mechanical stresses due to inefficient gas distribution and seal configurations, leading to reduced yield and cell deterioration.
Innovation Solution
A novel configuration featuring a third seal inserted into a porous substrate contact element, ensuring gas distribution only to the electrochemically active surface, combined with glass-ceramic or solder beads for enhanced leaktightness and stress distribution, increases gas conversion efficiency and reduces mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas is distributed to the entire cathode/anode surface including peripheral zones, then the device complexity is reduced, but the gas conversion rate decreases due to steam flowing into non-active zones
Solution Approach 1:
The cathode or anode surface is segmented into an electrochemically active surface and a peripheral non-active zone. The third seal inserted into the porous substrate contact element creates a boundary that restricts gas distribution to only the active surface area, preventing steam from flowing into peripheral zones where it would not participate in electrochemical reactions, thereby improving gas conversion rate.
Solution Approach 2:
Different zones of the cathode/anode are given different functional qualities: the central electrochemically active surface is designed to receive and process steam for electrochemical reactions, while the peripheral zone is excluded from steam distribution. The third seal implements this local differentiation by creating a sharp boundary between gas-distributed and non-distributed regions, ensuring steam is delivered only where it can be effectively converted.
2Reliability
If glass-ceramic or solder beads are used for sealing, then the leaktightness and stress distribution improve, but the manufacturing complexity increases
Solution Approach 1:
The sealing system uses composite materials combining glass-ceramic beads or solder beads with the porous substrate contact element. These composite sealing structures provide enhanced leaktightness and mechanical strength, creating a reliable seal between the contact element and the cathode/anode while distributing mechanical stresses effectively across the sealing interface.
3Device complexity
If the seal is positioned at the periphery of the cell, then the gas distribution is simplified, but mechanical stresses cause cell deterioration
Solution Approach 1:
The third seal is positioned in a different spatial dimension - inserted into the porous substrate contact element rather than being placed only at the peripheral interface between interconnectors. This dimensional relocation allows the seal to provide structural support and stress distribution within the contact element matrix, protecting the cell from mechanical deterioration while maintaining simplified peripheral gas distribution pathways.
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
This configuration achieves 100% gas conversion and minimizes detrimental mechanical stresses, ensuring effective gas distribution and electrical continuity while maintaining the integrity of the cell stack.
Implementation Method 1
a third seal, inserted into the porous substrate of the first contact element, bearing against the first interconnector and the cathode by being arranged at the periphery of the conduits for supplying steam and for recovering the hydrogen produced, respectively
Implementation Method 2
a first electrical contact element, different from the interconnectors, in mechanical contact on the one hand with the first interconnector and on the other hand with the cathode; the first electrical contact element being a porous substrate
Implementation Method 3
the electrolyte 3 inserted between the two electrodes 2, 4 is the site of migration of the O2− ions under the effect of the electrical field created by the difference in potential imposed between the anode 4 and the cathode 2
Implementation Method 4
the electrolysis of water is an electrolytic reaction that decomposes water into gaseous dioxygen and dihydrogen by means of an electrical current, according to the reaction: H2O→H2+1⁄2O2
Implementation Method 5
combined with glass-ceramic or solder beads for enhanced leaktightness and stress distribution
Data Source
AI summary
The invention relates to arranging a new seal within a porous substrate which forms the contact element of each hydrogen circulating electrode, such as the cathode for an SOEC reactor and the anode for an SOFC fuel cell, and in the periphery of the electrode beyond the ducts for supplying and recovering gases, in order to force the gases to circulate into the only useful zone of the cell which corresponds to the electrochemically active surface of the electrode. Thus, all of the gases supplied can be converted.