Abstract
A direct methanol fuel cell (DMFC) is considered as prospective power sources for portable devices and is studied intensively. Although a fuel-strage-type one seems to be much practical, in many cases, experiments using a fuel-supply pomp are conducted. In this study, effects of fuel feed method on DMFC performance are investigated. It is shown that the output power of fuel-storage-type DMFCs decreases gradually because of development of a concentration boundary layer and so on. Next, a simple method for estimation of fuel concentration at the anode catalysis layer is proposed and its effectiveness is shown. Finally it is shown that by supplying fuel as a vapor, DMFC keeps higher performance than that of a liquid-feed type, but because of dry up of membranes, its performance goes down significantly after a long operation.
