Fuel Management

Fuel managements of a PEMFC system can be classified as flow-through mode, recirculation mode, and dead-end mode.In the flow through mode, excess hydrogen is supplied to the anode to remove water diffused from the cathode, resulting in lower hydrogen utilization.In the recirculation mode, non-reacted residual hydrogen is recirculated back to the supply line by a pump or an ejector. In the dead-end mode, a pressure regulator is installed at the inlet of the anode to reduce the pressure of hydrogen from a gas tank, while a solenoid valve is placed at the outlet to seal the anode.

Dead-ended Anode

Distribution of local current density was measured by a specially designed single cell, in which 20 leads were attached on the anode graphite plate.

Recirculation

A novel configuration for anode recirculation and a gas management strategy are proposed and verified by experiments. Two valves are installed in the recirculation line. The anode is operated in four modes (dead-end, recirculation, compression, and purge), and the real-time local current density (LCD) is monitored for gas management purposes. The results show that the LCD distribution is uniform during the recirculation mode and nonuniform during the dead-end and compression modes.