Experimental and computational evaluation of water management and performance of a bio-inspired PEM fuel cell in comparison to a conventional flow field

Fuel cells are being increasingly used in various stationary and transportation power applications due to their higher energy efficiency and lower pollution. Flow field design in Proton Exchange Membrane (PEM) fuel cells is a major area of research for performance improvement. Bio-inspired flow field designs have significant potential for increased performance by effective distribution of reactants with better water management capabilities. In this study, a bio-inspired flow field design, formulated using Murray\u27s law and mimicking a typical leaf venation pattern, is experimentally and computationally investigated in comparison to a conventional single serpentine design. Experiments are conducted using a special transparent fuel cell assembly with copper as the conductive channel and current collector so that liquid water within the fuel cell channels can be directly visualized. Overall performances of both bio-inspired and conventional PEM fuel cells are also quantified with the corresponding polarization and power curves. Moreover, advanced computational simulations are carried out to predict pressure, velocity, and reactant and product distributions within the cells. The measurements and simulations clearly demonstrate the superior performance of the bio-inspired design with a 30% increase in peak power density in comparison to the conventional design. The observed water management capabilities as well as the computed parameters support and complement this overall result, quantify different types of two-phase flows within the fuel cell micro-channels, and help elucidate the underlying physical and electrochemical processes. The results are expected to significantly contribute to the improvement and optimization of nature-inspired PEM fuel cells. --Abstract, page iii