Methods of Making and Using Tubular Solid Oxide Fuel Cells (SOFCs)

Human-occupied vehicles and autonomous vehicles such as rovers and landers may benefit from the fuel flexibility and high energy density of solid oxide fuel cells (SOFCs), compared to batteries and polymer electrolyte membrane (PEM) systems. Fuel systems greater than 1 kW are traditionally planar and exhibit high volumetric power density; however, due to large sealing areas, they have poor cycling characteristics. Recently, 250 cycles on a Tubular SOFC (T-SOFC) system (Protonex Technology Corp.) was demonstrated. Hot zones designed around T-SOFCs have a lower packing density, but significantly better cycle life and start times, making them an ideal solution. By increasing the power density of T-SOFCs, overall hot zone and system volumetric power densities can be greatly improved. Extending the methodology of freeze-casting to T-SOFCs will provide a system with the micro-structural advantages of their planar counterpart, but with the rapid thermal cycling capacity of traditional extruded SOFCs.