A transient, multi-phase and multi-component model of a new passive DMFC

A 2-dimensional, transient multi-phase, multi-component fuel cell model is developed to model a passive fuel delivery system including the fuel cell itself for a direct methanol fuel cell (DMFC). This model captures evaporative effects, as water and fuel management are crucial issues. The evaporation/condensation rates are formulated in a manner to capture non-equilibrium effects between the phases. Also, the full kinetics are modeled at both the anode and cathode catalyst layers, along with the electric potential of the membrane, catalyst and gas diffusion layers. The fuel cell operation is examined by quantifying the fuel consumption due to chemical reaction and evaporation as a function of feed concentration. The passive delivery system utilizes a porous media to passively deliver methanol to the fuel cell while controlling the concentration of methanol at the anode side to limit the amount of methanol cross-over. The results illustrate the feasibility of the passive thermal-management system, and characterize the relevant transport phenomena.