Numerical study on the cathode flooding of direct humidified proton exchange membrane fuel cell

Abstract In proton exchange membrane fuel cell (PEMFC) stack, the water management in the cell is required in order to ensure high cell performance. The water dry-out interferes with the proton migration in the electrode and electrolyte, and the water flooding interferes with the reactant gas transfer in the gas diffusion layer, consequently these phenomena affect the cell performance. One of the approaches to prevent the dry-out, a direct humidified cell with the channel to supply liquid phase water has been considered. In this cell configuration, sufficient water will be supplied to the anode, however the migrated water to the cathode from the anode shall be removed immediately in order to prevent the flooding. In this paper, numerical analysis that includes the behavior of the electrode reaction, heat transfer, gas flow, and evaporation and condensation of water was conducted regarding a direct humidified model cell. The co-flow and counter-flow of fuel and oxidant gases were considered for the pressure conditions of 1 atm and 3 atm. The water distribution in the vapor phase and liquid phase at the oxidant gas and cathode were calculated, and as a result of those, the flooding characteristics for each condition were evaluated.