Behavior of a Single Direct Methanol Fuel Cell in Stacks at Air Maldistribution Conditions

Abstract

The air maldistribution through different individual cells is frequently encountered in direct methanol fuel cell (DMFC) stacks since most stacks utilize parallel flow configuration. This air maldistribution has been recognized as one of the most important causes for the performance loss and even durability loss of DMFC stacks. To better understand the impact of air maldistribution, the behavior of a single DMFC at various air flow rates (AFRs) is investigated both experimentally and numerically. Special attention is paid to the variation of cell voltage with AFR. It is found that the cell voltage drops significantly when the AFR decreases below a critical value. With the further drop of AFR, the cell voltage descends more sharply and even becomes negative at ultralow AFRs. The reasons for this unique behavior of cell voltage with AFR are explored in detail within this work.