Effect of Interconnector Rib on Optimization of SOFC Structural Parameters

Abstract

Interconnector (IC) is a key component for current collection in solid oxide fuel cell (SOFC) stacks, but leads to uneven distribution of gas (especially O2) and significantly reduces the power density. In this paper, a 3D numerical model is developed to study the effect of interconnector on the optimization of cathode structures of a planar SOFC. After model validation, parametric analyses are conducted to investigate the effects of cathode structural properties on the SOFC performance and temperature distribution, considering the interconnect dimensions and parameter variations along the flow channel. It is found that the interconnector causes more non-uniform distribution of oxygen in the downstream cathode than in the upstream. Increasing porosity or cathode thickness can improve the oxygen uniformity and the cell electrochemical performance especially in the downstream. However, too high porosity (ε > 0.4) or too thick cathode (t c > 250 μm) can cause significant ohmic or concentration losses, respectively. Besides, gradient porosity can increase the oxygen uniformity (up to 6.5%) and reduce the concentration loss (up to 10.6%) especially under the rib. In addition, a higher temperature region is observed in the cathode area under the channel, while increasing the porosity, the cathode thickness or using gradient porosity all cause a more uniform temperature distribution.