Two-dimensional simulation of direct methanol fuel cell - A new (embedded)type of current collector

A two-dimensional numerical model of the direct methanol fuel cell with gas fuel is developed. Simulation of the cell with current collectors of conve ntional geometry reveal the formation of fuel-depleted, "shaded" regions in the cathode and anode catalyst layers. These regions are positioned in fro nt of current collectors, farther from the gas channel windows. Another dis advantage of the conventional geometry is the concentration of electron cur rent at the edges of current collectors. Based on the simulation results, a new design of current collectors is suggested. It is beneficial to positio n current collectors inside the backing and catalyst layers, parallel to th e flow of the fuel. These embedded collectors do not produce shaded regions in the catalyst layers. Two plausible geometries of such collectors are co nsidered: of rectangular and circular shape. Simulations show that dependin g on the transport properties of the backing and catalyst layers the embedd ed current collectors may significantly improve the performance of the fuel cell. This conclusion is valid also for hydrogen-oxygen fuel cells. (C) 20 00 The Electrochemical Society. S0013-4651 (99)07-093-7. All rights reserve d.