Analysis of the nonlinear dynamics of a direct methanol fuel cell

Abstract

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 equation of index one. Dynamic simulation 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

Current Status of and Recent Developments in the Direct Methanol Fuel Cell

“…10. During experiments it was found that a pulsed periodic methanol feeding strategy can result in a significant cell voltage increase [41,42]. Simulations show the same behavior.…”

“…. Possible reaction mechanism for the electrochemical methanol oxidation and corresponding rate equations, adopted from [41].…”

“…To the authors' knowledge, dynamic models of the DMFC have not been published so far, except in [41,42]. There, the modeling strategy follows the idea of a modular composition of the model on hierarchical length scales from pre-defined modules.…”

Hydrodynamic characterisation and modelling of anode flow fields of Direct Methanol Fuel Cells

“…In the studies of Scott, Sundmacher and colleagues [9][10][11][12], a frequently used volumetric flow rate with the cells presented in [9] is 1.36 ml/min. This corresponds to a very low Reynolds number of Re = 1.32 inside the channels (details and comparisons see [5]).…”

Methanol crossover effect on the cathode potential of a direct PEM fuel cell

“…Several investigations have focused on the direct methanol fuel cell, and have shown that the performance of the cell is strongly affected by methanol crossover from the anode to the cathode compartment [1][2][3][4]. This phenomenon is accompanied by a reduction in cell voltage, which depends on experimental parameters such as fuel concentration, applied current density, stoichiometric factor and temperature [3,4].…”