Water management issues during load cycling under high temperature and low humidity conditions relevant for heavy-duty applications of PEMFC

To meet the increased requirements for efficiency and compactness of the Polymer Electrolyte Membrane Fuel Cell (PEMFC) system for heavy-duty vehicles (HDVs) application, PEMFC has to operate under high temperature and low humidity (HTLH) conditions to reduce the parasitic power consumption of radiators and the size of humidifier. However, HTLH would negatively affect the performance and durability of PEMFC. Through conducting in-situ current mapping, this paper found highly inhomogeneous current in-plane distribution during current cycling under HTLH conditions, which is attributed to the self-reinforced feedback of local current density and membrane water content. Instead, under the situations where current increase is prior to the temperature increase, PEMFC would have much more uniform in-plane current distribution and membrane water distribution, resulting in more efficient utilization of the produced water in a dry environment.