Simultaneous measurement of local current and temperature distributions in proton exchange membrane fuel cells with dead-ended anode

Abstract

The dead-ended anode (DEA) operation could cause local flooding and local hydrogen starvation in proton exchange membrane fuel cells (PEMFCs), resulting in drastic changes in fuel cell performance. In order to study the detailed local dynamic characteristics of DEA operation, simultaneous measurements of the dynamic variation of local current and local temperature in a PEMFC with DEA have been performed using a local current measurement gasket and micro thermocouples. The results show that the local fuel cell performance distribution gradually becomes uneven during DEA operation and the evolutions of local current and temperature strongly depend on the locations along the flow channel. The highest local current and local temperature are observed near the anode inlet, posing serious threats for the local fuel cell. Furthermore, with anode purging, the current distribution becomes uniform quickly due to the fast mass transfer capacity of hydrogen, but the local temperatures take much longer time to become uniform and stable because of the thermal capacity of fuel cell components. The anode purging also causes local temperature undershoots and the amplitude is over 4℃ in this study. Finally, the effects of operating conditions are discussed. The local current and temperature distributions become more uneven as overall operating current increases and operating temperature decreases. The local temperatures are all reduced as anode inlet pressure and air stoichiometry increase due to the enhanced convection cooling effect. It is demonstrated that measuring local current and temperature is effective in investigating local dynamic performance of PEMFCs with DEA.