Spatially-resolved current and impedance analysis of a stirred tank reactor and serpentine fuel cell flow-field at low relative humidity

A 20 cm(2) segmented anode fuel cell is used to investigate the performance of a hydrogen-air fuel cell at 1 atm. with two different flow-fields using spatially-resolved current and impedance measurements. A self-draining stirred tank reactor (STR) fuel cell and a single-channel serpentine fuel cell are compared with humidified and dry feed conditions. The current density distribution, impedance distribution, heat distribution and water evolution are compared for the two different flow-fields. With inlet feed dew points of 30 degrees C, the STR fuel cell and serpentine system performed comparably with moderate current gradients. With drier feeds, however, the STR fuel cell exhibited superior overall performance in terms of a higher total current and lower current, impedance and temperature distribution gradients. The STIR fuel cell design is superior to a single-channel serpentine design under dry conditions because its open channel design allows the feed gases to mix with the product water and auto-humidify the cell. (c) 2006 Elsevier B.V. All rights reserved.