Enhancement effects of the obstacle arrangement and gradient height distribution in serpentine flow-field on the performances of a PEMFC

The structure of flow-filed in the cathode-side channel played an important role to the performances of proton exchange membrane fuel cell (PEMFC) since it significantly influenced the transfer of reactant gas and the flooding phenomenon at the interface between gas diffusion layer (GDL) and catalyst layer (CL). For improving the performances of PEMFC from the structure of flow-field, serial obstacle was arranged into the channel, the effects of obstacle’s arrangement manner and the height distribution were numerically investigated on a PEMFC with tri-serpentine channel. Compared to the conventional channel, the presence of obstacle was observed could enhance the transfer of reactant gas towards GDL and widen the working range of current density, arranging obstacle in the back of channel (rear-obstacle) could obtain the most uniformity of reactant gas at the GDL/CL interface albeit arranging obstacle throughout the channel (full-obstacle) could obtain the maximal value of current density. To the manner of rear-obstacle arrangement, the height distribution of serial obstacle was found have remarkably impacts on the performances of PEMFC, if the heights were distributed in power function, a higher exponent (more than unity) could obtain more stable distribution of current density along the channel with weaker flooding phenomenon, but a smaller exponent (more than unity) could significantly raise the net power.