An experimental study on the purge characteristics of the cathodic dead-end mode PEMFC for the submarine or aerospace applications and performance improvement with the pulsation effects

In polymer electrolyte membrane fuel cells for the submarine or the aerospace systems, the pure hydrogen and oxygen are generally supplied to both sides of the membrane electrode assembly (MEA). Additionally, the fuel cell becomes a dead-end system which needs no fuel and oxidant supplying devices such as a blower, a fan and a re-circulation unit, therefore, the improvement in efficiency and the simplification of the system are expected. Instead, the purge process for removing the water that is produced in the reaction is necessary for the stable and durable system operation. However, during a purge process, small amount of oxygen can be discharged with the water. Thus, the number of purge cycle should be minimized for saving the oxidant. This paper presents experimental results on the periodic characteristics of the voltage change in the cathodic dead-end mode for various conditions. Moreover, the pulsation effect is introduced and applied to the outlet of the cathode channel for decreasing the purge frequency. The experimental results show that the pulsation effect decreases the voltage decay rate, and makes the interval between two purges about three times longer than that without the pulsation effect, which can make the oxidant efficiency of the dead-end mode operation higher. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.