Semi-analytical ID plus ID model of a polymer electrolyte fuel cell

Semi-analytical model of polymer electrolyte fuel cell (PEFC), which takes into account oxygen and water transport across the cell and along the channel is developed. Analytical formulas for along-the-channel profiles of local current density at large voltage loss are obtained. These expressions show that the cell may operate in one of the three regimes: (i) oxygen-limiting (local current density j exponentially decreases with the distance z along the channel); (ii) water-limiting (i exponentially increases with z); (iii) mixed regime: water-limiting close to the channel inlet and oxygen-limiting in the rest part of the cell. Recently measured and model profiles of local current density are in good agreement. In the mixed regime a large parasitic along-the-channel proton current may arise. The expressions for the limiting current density of the cell, for optimal feed composition and for optimal oxygen stoichiometry are derived. (C) 2004 Elsevier B.V. All rights reserved.