Parallel Manifold Effects on the Heat and Mass Transfer Characteristics of Metal-Supported Solid Oxide Fuel Cell Stacks

Abstract

The metal-supported solid oxide fuel cell (SOFC) was introduced as a new fuel cell design because it provides high mechanical strength and blocks gas leakage. Ordinary SOFCs should be manufactured in a stack because a single cell does not have sufficient capacity for a commercial system. In a stack, heat and mass transfer, which affects the performance, is altered by manifold structures. Therefore, this paper studied three kinds of manifold designs using numerical analyses. Governing equations and electrochemical reaction models were calculated simultaneously to conduct multiphysics simulations. Molecular diffusion and Knudsen diffusion were considered together to predict gas diffusion in a porous medium. Simulation results were compared with experimental data to validate the numerical code. There was a high current density with a high partial pressure of reactant gas on the hydrogen inlet and at the point where the hydrogen channel and the air channel intersected. The average current density of a cross-co flow design was 4890.5 A/m2, which was higher than the other designs used in this study. The average current densities of the cross-counter flow design and the cross flow design were 4689.1 and 4111.8 A/m2, respectively. The maximum pressure was 750 Pa in the air manifold and 32 Pa in the hydrogen manifold. The temperature of the bottom cell was lower than the top cell because the bottom cell had little exothermic heat by low polarization.