Experimental Study of Orientation Effect on Performance of a Dead-End H2/02 PEM Fuel Cell Short Stack

In this paper for the first time, a new design for a polymer electrolyte membrane (PEM) fuel-cell stack is presented which can achieve higher fuel utilization without using hydrogen and oxygen recirculation devices such as hydrogen pumps or ejectors, that consumes parasitic power and require additional control schemes. The humid and water separator sections are integrated with stack and extremely reduced the size and volume of stack. For effective water removal and increasing local stoichiometry, stack is divided to blocks by conducting the outlet gas of first stage to a separator and reentering to second stage. The active area of cell is 225 cm2 (15 cmxl5 em) and there are 3cell at first stage and 1 cell in second stage. In this design, a higher gaseous flow rate is maintained at the outlet of the fust stage 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 orientation in gravity direction increases the performance of PEM fuel cell.