CFD prediction of shunt currents present in alkaline fuel cells

Abstract

A CFD study was conducted for the electrolyte transport in a single-cell alkaline fuel cell. The transport model that accounts for the balance of mass, momentum, energy, species and electric charge in the electrolyte was solved. The CFD results captured the presence of primary and secondary (shunt) currents in the liquid electrolyte. The shunt currents were present in the regions adjacent to the separator inlet and exit, but not inside the separator nor in the extended channels. The calculated local shunt current density in the corner regions of the separator inlet and exit was higher than the average primary current. The results also showed that the IR loss due to the electric potential drop at high current densities is comparable to the overpotential loss at the anode. Passive and active mitigation measures against the shunt currents were suggested.