Analysis of the nonlinear dynamics of a direct methanol fuel cell

This paper is related to the analysis of the dynamic behaviour of a liquid-feed direct methanol fuel cell (DMFC) under different operating conditions, based on an isothermal model accounting for the mass balances, the charge balances, the reaction micro-kinetics and the mass transport phenomena. Conceptually, the fuel cell system is decomposed into its subsystems (anode and cathode compartments, diffusion layers, catalyst layers on both electrodes, proton exchange membrane (PEM)). The models of the subsystems are coupled to a DMFC model which is represented by a set of differential-algebraic equations of index one. Dynamic simulations with this model show that the undesired cross-over of the reactant methanol through the PEM can be reduced by periodically pulsed methanol feeding to the anode compartment. The simulated results are in good agreement with experimental cell voltage data obtained from a laboratory-scale DMFC which was operated with different dynamic feeding strategies.