Some of the new liquid water management systems in polymer electrolyte membrane (PEM) fuel cells hold great potential in providing flood-free performance and internal humidification. However, current water management systems entail major setbacks, which either inhibit implementation into state-of-the-art architectures, such as stamped metal flow-fields, or restrict their application to certain channel configurations. Here, a novel water management strategy is presented that uses capillary arrays to control liquid water in PEMFCs. These capillaries are laser-drilled into the land of the flow-fields and allow direct removal (wicking) or supply of water (evaporation), depending on the local demand across the electrode. For a 6.25 cm2 active area parallel flow-field, a ∼92% improvement in maximum power density from capillary integration was demonstrated. The proposed mechanism serves as a simple and effective means of achieving robust and reliable fuel cell operation, without incurring additional parasitic losses due to the high pressure drop associated with conventional serpentine flow-fields.
Cho, J. I. S., Neville, T. P., Trogadas, P., Bailey, J., Shearing, P., Brett, D. J. L., & Coppens, M. O. (2018). Capillaries for water management in polymer electrolyte membrane fuel cells. International Journal of Hydrogen Energy, 21949–21958. https://doi.org/10.1016/j.ijhydene.2018.10.030