Pressurized testing of a planar solid oxide fuel cell stack

Gas leakage often occurs in planar solid oxide fuel cell (SOFC) stacks due to small pressure differentials (2–3 psi) between the process flows and external pressure. This gas leakage can initiate localized burning and degradation mechanisms, which result in lower stack efficiency, reduced stack lifetime, and higher overall cost. A more durable planar SOFC design that can accommodate higher operating pressure would contribute to higher efficiency and more versatile SOFC system integrations. This manuscript examines the performance of a 60-cell, planar SOFC stack up to 45 psia. SOFC stacks can be successfully operated at elevated pressure by containment in a pressure vessel and equalization of the vessel pressure to the process pressure (i.e. anode and cathode gas flows). SOFC stacks display pressure-dependent voltage in accordance with theory, suggesting that an absolute efficiency gain of 2–3% by operating at 45 psia versus ambient pressure (15 psia) is achievable.