Performance of unit PEM fuel cells with a leaf-vein-simulating flow field-patterned bipolar plate

This study was conducted to investigate the performance of 25-cm(2)-unit polymer electrolyte fuel cells, the bipolar plate of which has a flow field that simulates leaf veins. The test flow fields were serpentine, parallel, and net leaf flow fields mimicking ginkgo and dicotyledonous leaves. The maximum power density for the ginkgo flow field was 7% lower than that for the serpentine flow field, and 40% higher than that for the parallel flow field under normal operating conditions. However, the air-feeding power required by the ginkgo was only 3% of that required by the serpentine. The usable power density for the ginkgo flow field was the highest among all flow fields. Additionally, the water-removal capability of the ginkgo flow field was superior to that of the parallel and net leaf flow fields, but inferior to that of the serpentine flow field. Furthermore, the amount of water remaining in the flow field channels was found to be correlated to the length of the unit channel. Therefore, the ginkgo pattern can be considered to be an optimal flow field design for the fuel cell. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.