Solid Oxide Fuel Cell (SOFC) is prone to mechanical failure due to high operating temperature and structural stiffness. Numerical studies of a SOFC with different gas flow channel structures were carried out to evaluate channel structures impact on species and heat transport, cell performance, the stress concentration and thermal stress distribution. The accuracy and reliability of numerical model were verified by comparing with an experimental result. It is found that cell performance of the SOFC is affected by gas flow channel structure, which leads to the difference of temperature field and ultimately affects the thermal stress distribution in the cell. By changing the cross sections of the gas flow channels from rectangle to arch and round trapezoid, stress concentration is effectively alleviated and the thermal stress of the interconnect is significantly reduced. The magnitude of stress at the interface between different components is reduced by 18.2 to 40%. The work provides a valuable reference for SOFC stack structure design and insight on its operations.

The process of reactant transportation greatly affects the performance of solid oxide fuel cells (SOFCs). Therefore, a three-dimension numerical SOFC model was built to evaluate mainly the effect of the reactant transportation coupling of heat and mass transfer and electrochemical reactions, and the reliability of numerical calculations was validated. Numerical studies revealed the correlation of both increase of reactant concentration gradients and improved mass transfer capability of multi reactants in gas diffusion electrode with the enhancement of the SOFC performance, in the condition of enough supplies of the fuel and the oxidant. Further studies identified the oxygen ions conductivity in electrolytes played a critical role in energy output and thus the performance of SOFCs. For example, the current density would increase by 65% if the ionic conductivity of electrolytes doubled. This study gives insight into the significance of operational conditions, electrolytes, and structures on the ionic oxygen conductivity and further on the optimization of the SOFCs. Overall, the numerical modeling leads a clear path toward the optimization of SOFCs.