Experimental investigation on the effect of channel geometry on performance heterogeneity in hydrogen PEM fuel cell

Straight parallel graphite-based flow fields are experimentally assessed to evaluate the effect of geometrical parameters on the performance of polymer electrolyte membrane fuel cell. A 1+1D fuel cell model is exploited to evaluate the local operating conditions occurring along various positions of the flow field channel for different load requirements. The estimated operating conditions are implemented in a zero-gradient hardware to perform a broad experimental campaign, conducting tests under controlled and uniform operating conditions. The achieved experimental results depict the impact of the flow field geometry along different positions of the flow field channel under real operating conditions, identifying the individual contributions of the geometric parameters on water transport, oxygen transport and electrical resistance. The proposed methodology provides detailed information on the local operation of a large-area bipolar plate using a small-area sample, demonstrating the effect of rib and channel geometrical parameters on real-world operation of a PEMFC.