Single cell induced starvation in a high temperature proton exchange membrane fuel cell stack

Fuel and oxidant starvation are amongst the most critical phenomena affecting fuel cell durability. Reactant starvation during proton exchange membrane fuel cell operation can cause serious irreversible damages. In the present research, the effect of a selective induced starvation of reactant gases on the performance and degradation of a high-temperature PEM fuel cell is studied. A specifically designed 5-cell stack is used, which enables varying the gas supplied to any of the individual cells. The particularity of selectively starving only one cell in a controlled manner is one of the novelties of this study. Two different tests are performed actuating on the central cell (cell 3). They are denoted as moderate and severe starvation, depending on the intensity of the limitation imposed to the gases flowrate. Some relevant and novel results are obtained. It is verified that the performance degradation caused by a moderate starvation of the reactant gases in a cell is reversible. On the contrary, the damages caused by an aggressive gas starvation, which is also maintained in time (30 min), are irreversible. However, the behavior of the rest of the cells is barely affected by the gas starvation to cell 3. Thus, the other major novelty of the present work is the evidence/proof of the ability of a stack with a starved and highly degraded cell, to continue operating, although with a drastic reduction in the total generated current.