The Cell Voltage Loss of PEFC under the Low Humidified Operation

Abstract

It is well known that the operation with low humidified reactants accelerates cell voltage loss of PEFC. On the other hand, the mechanism of the voltage loss is not clear. On this study, two kinds of cells which have different thickness membrane (15 and 30 µm) were evaluated under operation with low humidified reactants to clarify the voltage loss mode. The study indicates that there are two different cell voltage loss modes. For 15 µm cell (a thin membrane cell), the cell voltage decayed along with open circuit voltage decrease with H2 crossover increase. It is the case that H2 crossover depresses cell voltage. For 30 µm cell (a thick membrane cell), the cell voltage decayed along with open circuit voltage decrease without H2 crossover increase. This decay mechanism of voltage loss without H2 crossover was focused to study. New methods for measuring humidity distribution and current distribution in a cell were introduced for further analyze. It is found that effective catalyst area loss in cathode catalyst layer could depress cell voltage. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.