Design and Operation of Solid Oxide Electrochemical Cell Systems for Space Applications

Aaron Bain Dissertation Defense, March 30, 2023

Constraints on modern spacecraft electrical power delivery are created by the overall lack of gravimetric energy density in modern batteries and in particular the inability for solar panels to deliver high power output for a prolonged period of time. To reduce these constraints, we seek to design a solid oxide fuel cell (SOFC) system which will consume onboard bipropellants usually reserved for on-orbit maneuvering thrusters and enhance current fuel cell materials technology to enhance performance and ensure against degradation. Atmosphere independent fuel cells have higher theoretical specific energy than batteries. Solid oxide fuel cells are widely considered to be an ideal power source across a range of industries in the near future due to their high efficiency, high power output potential, and quiet operation. Vehicle implementation, especially in the aerospace field, can benefit from fuel cell operation where the high volumetric energy density of liquid fuels allows for much longer duration operation than electric batteries would allow. In aerospace, mission length, low weight, and high-power output are necessary criterion for any mobile power generation solution. This research aids the progress of solid oxide fuel cell systems for space applications through a multi-scale approach. Microstructural and electrochemical theory is applied to design SOFC electrodes with higher performance while also reducing risk of damage during launch and thermal cycling. Three plant designs, and their respective dynamic models for analysis, are put forward as candidates for power systems utilizing solid oxide electrochemical cells; a hypergolic bipropellant-enabled variant, a regenerative variant, and an electrochemical heat engine.