Abstract
Although polymer electrolyte fuel cells (PEFCs) are commercially available, there are still many problems that need to be overcome to further improve their performance and increase their usage. The cell performance depends strongly on water management in the PEFC. In this study, two schemes for optimization are proposed to improve the water management in gas channels and GDL. One was a combination of novel gas channel with micro-grooves, which are manufactured inside gas channel walls, and novel GDL with wettability distribution. The cell performance was examined by changing the cell temperature, relative humidity of gas and air velocity. The other was a novel design of cathode channel with sub-channel. The main-channel was fed by moist reactant while the sub-channel supplied by dried reactant with the whole reactant flow rate invariable. Three positions of sub-channel inlet and the dried reactant flow rates were experimentally studied to evaluate the cell performance. It was shown that the both schemes could improve the cell performance. That is, the PEFC with micro-grooves and hybrid GDL showed higher performance than the conventional PEFC without grooves. Especially, the value of maximum current density was increased by about 19.5% when air velocity is 8.0m/s. Meanwhile, as the position of the sub-channel inlet was 30% of the cathode channel length, the dried reactant flow rate was 70%, the cell with sub-channel achieved the best performance.
