Experimental investigation on uniform and zigzag positioned porous inserts on the rib surface of cathode flow channel for performance enhancement in PEMFC

The designs of flow channels are highly influencing the performance of PEMFC. A serpentine flow channel with Uniform and Zigzag positioned porous carbon inserts on cathode flow plate is experimentally analyzed in this paper. Addressing the flooding problem, a single PEMFC having an active area of 25 cm2 with various flow channel designs on the cathode flow plate namely serpentine, uniform and zigzag pin type; and flow channel with 2 mm cubical porous inserts on the uniform and zigzag pin type is experimentally investigated. The influence of porosity of carbon inserts on the cell performance is also studied by varying the porosity of carbon inserts in the range of 60-70%, 70-80%, 80-90% respectively. The results show that the flow channel with zigzag positioned porous inserts having 80-90% porosity has improved the power density and current density by 11.5% and 7% respectively when compared to the conventional serpentine flow channel. The reason for the increase in such performance is that, the porous insert on the rib surface removes the accumulated liquid water from the rib surface through the capillarity of its porous structure and eliminates the stagnant regions under the rib, thereby reducing liquid flooding in the interface between rib and GDL.