Performance and Transport Characteristics of Planar Solid Oxide Fuel Cells with Connected-Rib Interconnectors

Interconnector geometry strongly affects gas transport, polarization loss, and pressure drop in planar solid oxide fuel cells (SOFCs). In this study, four interconnector configurations were investigated for an anode-supported planar SOFC, including one conventional straight-rib interconnector and three connected-rib interconnectors, namely circular-rib (CI), rectangular-rib (RI), and triangular-rib (TI) designs. A three-dimensional multi-physics model coupling electric field, flow field, species transport, and temperature field was established and validated against experimental polarization data of the conventional straight-rib cell. To ensure a fair comparison, all interconnectors were designed with the same interconnector–electrode contact area. The effects of rib configuration on electrical performance, overpotential components, reactant distribution, velocity distribution, and pressure drop were systematically analyzed. At 800 °C, the peak power densities of CI-SOFC, RI-SOFC, and TI-SOFC increased by 4.9%, 9.7%, and 11.7%, respectively, compared with SI-SOFC. The connected-rib interconnectors mainly reduced cathode-side activation and concentration overpotentials by improving oxygen redistribution beneath the ribs. Among the four configurations, the TI-SOFC showed the highest power density and the strongest under-rib transport enhancement, while the RI-SOFC provided a better compromise between flow uniformity and pressure drop.