Experimental investigation of dry feed operation in a polymer electrolyte membrane fuel cell

• Product water is used to hydrate the polymer electrolyte membrane.
• Non-uniform under-rib convection in the mixed distributor aids to retain water.
• Voltage depends on operating temperature and stoichiometry in co-flow mode.
• Voltage independent of operating temperature and stoichiometry in counter-flow mode.
• Horizontal orientation of the flow field is ideal for self-humidified operation.

The possibility of achieving self-humidified operation of a polymer electrolyte membrane fuel cell, without any major modifications to the conventional fuel cell design, is investigated experimentally. The flow distributor is designed such that the non-uniform under-rib convection aids to retain product water in the fuel cell enabling a dry feed operation. The fuel cell is operated in a pseudo co-flow and pseudo counter flow modes at a constant current density and the transient change in voltage and temperature are recorded. In the pseudo co-flow mode, the voltage drops at higher temperature and reactant stoichiometries which is attributed to membrane dehydration at the inlet region of the cell. In the pseudo counter-flow mode, the voltage remains same at both low and high temperature operation and is found to be independent of reactant stoichiometry. A horizontal orientation of the flow field, in pseudo counter flow mode, is found to be ideal for self-humidified operation at low reactant stoichiometries and cell temperature.