Oxygen Transport in Polymer-Electrolyte Fuel Cells with Interdigitated Air Channels in Porous Bipolar Plates

Interdigitated channels improve oxygen transport to the air electrode in polymer-electrolyte fuel cells with finely porous bipolar plates. The improvement can be attributed to better delivery of oxygen to the portion of the electrode occluded by the ribs that separate adjacent air channels. Enhanced removal of liquid water from the gas-diffusion layer by convection of air over the ribs is not an important factor when finely porous bipolar plates are used. The ratio of current densities generated by flow fields with parallel and interdigitated channels is independent of oxygen utilization and asymptotically approaches a minimum value at low voltage. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3509159] All rights reserved.