Fügen von Hochtemperatur-Brennstoffzellen
Planar solid oxide fuel cells as developed at Forschungszentrum Jülich are combined with steel interconnectors and casings to form fuel cell stacks that can be used as technical power sources. On the one hand, all the components must be joined gas-tight so that fuel and air cannot mix. On the other hand, the interconnectors have to be electrically insulated from each other and, where applicable, from the casing to prevent ohmic losses. Fuel cell stacks are operated at temperatures ranging from 750 to 1000°C under both oxidizing (air) and reducing atmospheres (fuel gas). In order to form gas-tight sealings under these conditions, a large number of glass-ceramic sealants were investigated. Dilatometric measurements were performed to determine the thermal expansion coefficient and the flow and shrink behavior during joining, and joining tests were conducted with different specimens representing the various joining geometries in the fuel cell stack. Finally, selected glass-ceramic sealants were used to join various designs of fuel cell stacks. By choosing the appropriate sealant and adapting the joining geometry to the possibilities of the sealant it was possible to reproducibly achieve gas-tight stacks, although their thermal cycling properties still need to be improved.
info:eu-repo/classification/ddc/620, Ingenieurwissenschaften, SOFC, Glaslot, Glaskeramik
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