Influence of porous carbon inserts on scaling up studies for performance enhancement on PEMFC

In order to reduce the effect of water flooding on larger active area of Proton Exchange Membrane Fuel cell (PEMFC), an enhanced flow distribution on the flow channel is mandatory. In this paper to mitigate the water flooding problem, experimental studies have been carried out on 25 cm2 and 70 cm2 active area of PEMFCs 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 types. The results show that the cathode flow field plate with zigzag positioned porous carbon inserts having 80-90% porosity has improved the current and power densities by 7% and 11.5% respectively, when compared to the conventional serpentine flow field plate for 25 cm2 PEMFC. The above procedure has been followed for scaling up studies from 25 cm2 to 70 cm2 PEMFCs for effective water management. It is concluded that the 70 cm2 PEMFC with zigzag positioned porous carbon inserts on the cathode flow field has increased the current and power densities by 8.7% and 20.6% respectively compared to the conventional serpentine flow field. The porous carbon inserts on the rib surface of the cathode flow field removes the accumulated liquid water from the rib surface through the capillarity of its porous structure, due to this the performance of PEMFC is enhanced in scaling-up studies with better water transport characteristics.