Thermal-stress analyses of an operating planar solid oxide fuel cell with the bonded compliant seal design

A thermo-electrochemical-structure model has been proposed in the present work to investigate the thermal behavior and the thermal-stress of a solid oxide fuel cell (SOFC) with the bonded compliant seal (BCS) design. A comprehensive numerical simulation model, employing the finite-volume approach, has been developed for the three-dimensional, multi-component, electrochemically, and chemically reacting flow of a single planar SOFC unit cell. The cell temperature predicted by the finite-volume model is imported to a finite-element model to estimate the thermal-stress with the BCS design. Effects of the cell voltage and the temperature non-uniformity on the thermal-stress of the SOFC have been investigated. Numerical results obtained from the present study show that an assumed isothermal SOFC configuration leads to an underestimate of the thermal-stress by 28% for the cell and 37% for the metal frame in comparison with those in practical operating conditions. Two factors are identified to be responsible for the thermal-stress. One is the residual stress, and the other is the temperature gradient. The dominant factor for the thermal-stress depends on the location and the cell voltage.