A Performance and Current Distribution Model for Scaled‐Up Molten Carbonate Fuel Cells

Abstract

The performance of scaled-up (100 cm**2) fuel cells with cross flow of fuel and oxidant has been modeled using the polarization characteristics of small-scale (3 cm**2) fuel cells. The model also yields the two-dimensional (superficial) current distribution. The performance predicted by the model approximates to within 4% the experimental data if a suitable average value is assigned to the effective cell impedance. The latter depends on the inlet gas composition but does not vary much with the current; its value may be estimated from small-scale cell data. Carbon monoxide conversion contributes appreciably to the performance of low Btu cells; it tends to make the current distribution less uniform. The presence of methane must be considered in pressurized cells, but it does not appear to be formed to a significant extent. The relative contribution of mass transfer and kinetic resistance to the cell impedance are discussed in light of recent experimental results.