PNNL

Abstract

This model is based on a closed-form calculation of SOFC voltage for a given current, fuel and air composition, and temperature. The response characteristics are adjustable to changes in stack component materials and dimensions as well as to electrode porosity. The model performs a ?unit-cell? calculation in the sense that it calculates performance at steady state, assuming that fuel composition, air composition and temperature are homogeneous over the active area. The usual overpotential terms account for ohmic resistance of the cell components, loss due to charge transfer at the electrodes, and losses due to diffusion of reactants into and products out of the porous electrodes. Although the form of the algorithm is based on theoretical treatments of the overpotential terms, several adjustable parameters are used to calibrate the model to closely match actual small-scale single-cell data that was taken over a range of temperatures and fuel compositions (see Simner et al, ?Development of Cathode Materials and Fabrication Techniques for Low Temperature SOFCs? elsewhere in these proceedings). The calibrated performance model algorithm is used to calculate electrochemical activity of each computational cell within a comprehensive electrochemical model of the stack (see Recknagle et al, ?Thermo-Fluid-Electrochemical Modeling of Planar SOFC Stacks in Three-Dimensions? elsewhere in these proceedings). This poster discusses unit cell performance using I-V curves predicted for a variety of chemical conditions and cell materials configurations.