This paper presents analytical and experimental studies on optimization of the gas delivery and current collection\r\nsystem in a proton exchange membrane (PEM) fuel cell for the objective of reducing ohmic loss, thereby achieving\r\nhigher power density. Specifically, the dimensions of current collection ribs as well as the rib distribution were\r\noptimized to get a maximized power density in a fuel cell. In the modeling process, the power output from a fixed\r\narea of membrane is calculated through analysis of an electrical circuit simulating the current from electrochemical\r\nreaction flowing to the current collectors. Current collectors of two-dimensional ribs and three-dimensional pillars\r\nwere considered. Analyses found that three-dimensional pillars allow higher power density in a PEM fuel cell.\r\nConsidering the mass transfer enhancement effect, three-dimensional pillars as current collectors in gas flow field\r\nmay be a good choice if the fuel cell operates at low current density and there is no liquid water blocking the flow\r\nchannels. The analyses did not consider the existence of liquid water, meaning the current density is not very high.\r\nThe study concluded that decreasing the size of both the current collector and its control area yields a significant\r\nbenefit to a higher power density. A preliminary experimental test in a PEM fuel cell has verified the conclusion of\r\nthe analytical work.
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