Optimum hydrogen flowrates and membrane-electrode clamping pressure in hydrogen fuel cells with dual-serpentine flow channels

Abstract

Hydrogen fuel cells have been designed and fabricated with an aim to investigate effect of cell clamping pressure and hydrogen flowrates on the performance of fuel cells. Fuel cells with active area 1.9 cm × 1.6 cm were fabricated with aluminum anode, cathode and other accessories. Membrane Electrode Assembly (MEA) was made up of nafion 212 (50 µm) membrane sandwiched between two gas diffusion electrodes (GDE) on either side of nafion membrane. Anode and cathode GDE had carbon cloth with 0.25 mg/cm2 and 0.50 mg/cm2 Pt loading, respectively. Double serpentine flow channels were used for the flow of hydrogen and oxygen at anode and cathode. Hydrogen was humidified with an external humidifier. Cells were fabricated with two clamping pressures, 5 kg/cm2 and 25 kg/cm2 both at 80 °C. Hydrogen and oxygen flowrates were varied from 10 sccm to 70 sccm. The polarization plots indicate that the cell with clamping pressure of 25 kg/cm2 and with a flowrate 20 sccm have higher power output (350 mW/cm2) compared to other flowrates thereby implying an optimum flowrate for a given design.