Abstract
This study investigates drying condition for the case when a small fan is added to a free-breathing proton electrolyte membrane fuel cell (PEMFC) operating with dry H_2 and air. Polarization tests were conducted on PEMFCs at cell temperatures between 30 and 50℃. The result shows that the cell performance strongly depends on the cell temperature and the stoichiometric flow-rates of cathode gas. The cell performance increases as cell temperature decreases from 50 to 30℃. In the condition where the air flow-rate is quite large, internal resistance increases due to the progress of drying, but it is compensated by the decreased concentration over-potential. The maximum performance was obtained at a small air flow-rate in a narrow pass between dry-out and flooding. This indicates that the flow rate of the fan should be designed relatively small, if a cell design of avoiding flooding is possible.
