Performance enhancement in a proton exchange membrane fuel cell with a novel 3D flow field

Flow field plays a vital role in the design and application of a proton exchange membrane fuel cell (PEMFC). Combined with the enhancement of the abilities of mass transfer and water removal in the flow channel, a new optimized three-dimensional (3D) flow field is proposed to investigate the water transport and cell operating characteristics. The 3D flow field is composed of several straight flow units arranged in a staggered manner with an inclination at the end, and the transition areas and subchannels between the flow units are subjected to hydrophilic treatment. The result indicates that the new type of flow field can effectively separate liquid water from the reactant flow and water can be partially removed through the subchannel. Compared with the conventional flow field, the 3D flow field could enhance the mass transfer ability and improve the PEMFC performance, especially at high current densities. Based on the field synergy principle, we prove that the synergic degree between the velocity vector and concentration gradient agrees with the performance changes under the turbulence of the staggered flow units and the effective mass transfer coefficient (EMTC) in the direction of electrochemical reaction of the 3D flow field is also enhanced.