Design and Analysis of an Innovative Dead-end Cascade-type PEMFC Stack at Different Orientations

In this paper, the design and experimental study of a 4-cells cascade-type polymer electrolyte membrane (PEM) fuel cell stack with integrated humidifiers and water separators are presented. The PEM fuel cell stack is subdivided into two stages to minimize the quantity of exhaust gases during operation. A dead-end condition is applied for both cathode and anode sides of the PEM fuel cell stack. In a dead-end mode, the end-stage is designed to entirely use the reactant gases in the operation. Periodical purging is utilized to remove the accumulated water or impurities from the cascade-type PEM fuel cell stack. Comparison of cascade-type PEM fuel cell stack operation in a dead-end mode with a flow-through mode is performed. Results revealed that integrating humidifiers and water separators with the stack improved the volume power density of the PEM fuel cell stack. Moreover, since more liquid water was produced on the cathode side, the fluctuation of purge cell voltage of the cathode side is higher than that of the anode side. In addition, a technique is applied to control the pressure fluctuation of both sides of the PEM fuel cell.