A numerical study of cell-to-cell variations in a SOFC stack

A numerical investigation of cell-to-cell voltage variation is performed by considering the impact of flow distribution and heat transfer on a SOFC stack. The stack model used is based on a one-dimensional co-flow cell model developed in prior work. The influence of radiative heat transfer between the PEN (positive electrode, electrolyte, negative electrode body) and the neighboring separator plates on the temperature distribution is also considered. Variations in cell voltage are attributed to asymmetries in stack geometry (boundary effects) and non-uniformity in flow rates, more particularly, flow thermal capacity. Simulations were done in a parallel computing environment with each cell computed in a separate (CPU) process. This natural decomposition of the fuel cell stack reduced the number of communicated variables thereby improving computational performance. The parallelization scheme implemented utilized a message passing interface (MPI) protocol where cell-to-cell communication is achieved via exchange of temperature and thermal fluxes between neighboring cells. (C) 2003 Elsevier B.V. All rights reserved.