Improvement of under‐the‐rib oxygen concentration and water removal in proton exchange membrane fuel cells through three‐dimensional metal printed novel flow fields

The porous electrode under the rib area suffers from lower local oxygen concentration and more severe water flooding than that under the channel, which significantly affect the performance of proton exchange membrane fuel cells. To improve the oxygen concentration and water drainage under the rib, a series of novel flow fields with auxiliary channels equipped with through-plane arrayed holes were manufactured by three-dimensional (3D) metal printing, and the cell performance, ohmic resistance and pressure drop were experimentally and numerically studied, respectively. The novel fields were based on the sophisticated modification of traditional serpentine and parallel flow fields, that significantly improved the cell performance at high current density with an optimal number or length of the auxiliary channels, owing to the trade-off between the electric resistance and mass transfer under the rib. This novel flow field design solved the trilemma of performance, pressure drop and manufacture feasibility through the implementation of 3D printing technology.