Water transport in the proton-exchange-membrane fuel cell: Measurements ofthe effective drag coefficient

The water transport in proton-exchange-membrane fuel cells has been experim entally investigated by measurements of the effective or net drag coefficie nt. Results are presented for a wide range of operating conditions (current density, temperature, pressure, stoichiometry and humidity of the inlet ga ses), as well as for different types of membrane-electrode-assemblies. It w as found that the humidity and the stoichiometry of the inlet gases had a l arge effect on the drag. Of the material properties investigated, the membr ane thickness was found to be the most significant parameter. Inspection of the cell performances showed that drying of the cathode was much more detr imental for the cell performance than drying of the anode. This was ascribe d to increased activation losses, which turned out to be extremely sensitiv e to the type of cathode used. (C) 2001 Elsevier Science B.V. All rights re served.