Analysis on the Rapid Voltage Drop Based on a New Air-Cooled PEMFC Stack Design

摘要

A new structure called Membrane-Electrode-Assembly-Plate unit with lateral hydrogen tube isdeveloped, which binding the periphery of the anode face of a bipolar plate with the periphery of theanode side of a membrane electrode assembly by using silicone adhesive. An air-cooled proton exchangemembrane fuel cell stack is assembled through stacking forty Membrane-Electrode-Assembly-Plateunits and mounting two hydrogen external manifolds. Consequently, the possibility of hydrogen leakageto the cathode side is excluded completely. The maximum power can temporarily reach 351.60 W at20.0 A. Eight-hour stack stability is tested at a constant current of 4.77 A, i.e., 100 mAcm-2. The averagevoltage drop rate of single cell is calculated as 0.852 mVh-1. It is explained that the rapid stack voltagedrop during eight-hour operation is caused by the formation, accumulation and spread of liquid waterinside both the anode and cathode gas diffusion layers and is reversible.