Gravity effect on the performance of PEM fuel cell stack with different gas manifold positions

The importance of gravity effect on the performance of proton exchange membrane fuel cell (PEMFC) has recently been recognized. In this paper, the effect of gravity on the performance of PEMFC has been investigated associating with different gas intake modes. The polarization curves of the stack with different positions of reaction gas inlet and outlet at varied gravitational angles are addressed in detail. The results indicate that the output power of PEMFC stack can be greatly enhanced at the optimized gravitational angle. Gas intake modes that were realized by varying the gas inlet and outlet positions strongly affect the stack performance as well. The optimized performance can be reached at the tilted angle of 90° when both air and hydrogen inlets are placed at the upper side of the stack, whereas the worst performance occurs at the tilted angle of 90° when air and hydrogen flow into the channel from the bottom side of the stack. These results have important implications for PEM fuel cell design and operational strategies. In order to improve the performance, fuel cells should be designed and operated at the optimized gravitational angle and gas inlet/outlet position. Copyright © 2011 John Wiley & Sons, Ltd.