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 conventional geometry reveal the formation of fuel-depleted, "shaded" regions in the cathode and anode catalyst layers. These regions are positioned in front of current collectors, farther from the gas channel windows. Another disadvantage of the conventional geometry is the concentration of electron current at the edges of current collectors. Based on the simulation results, a new design of current collectors is suggested. It is beneficial to position current collectors inside the backing and catalyst layers, parallel to the flow of the fuel. These embedded collectors do not produce shaded regions in the catalyst layers. Two plausible geometries of such collectors are considered: of rectangular and circular shape. Simulations show that depending on the transport properties of the backing and catalyst layers the embedded current collectors may significantly improve the performance of the fuel cell. This conclusion is valid also for hydrogen-oxygen fuel cells. (C) 2000 The Electrochemical Society. S0013-4651 (99)07-093-7. All rights reserved.