Experimental Study of the New Design 2.5kW Dead-End H2 /O2 PEM Fuel Cell Stack with New Design to Improve Fuel Utilization

Proton exchange membrane fuel cells with a dead-ended anode and cathode achieve high hydrogen and oxygen utilization by a comparatively simple system. In this paper, a new design of proton exchange membrane fuel cell stack is presented. The basic concept of the proposed design is to divide the cells of the stack into several blocks by conducting the outlet gas of each stage to a separator and reentering to the next stage, thereby constructing a multistage anode and cathode. In this design, a higher gaseous flow rate is maintained at the outlet of higher than 85% of cells, even under dead-end conditions, and this results in a reduction of purge-gas emissions by hindering the accumulation of liquid water in the cells. The result shows that the dead-end mode condition has the same performance as an open-end mode. The stack power at the current density of 1200 mA/cm2 is 2.5kW and the voltage of all cells is bigger than 0.6V. This means that the stack can achieve to the power higher than 3kW, although all cells voltage is higher than the restriction voltage of 0.4V. Furthermore, the optimum time for opening and clothing of purge valve are 2 and 4s for anodic cells and 2 and 6s for cathodic cells.