Performance improvement in a proton exchange membrane fuel cell with an innovative flow field design

Abstract

The flow field of the proton exchange membrane fuel cell (PEMFC) controls mass and water transfer; it significantly impacts the fuel cell's performance. It is critical to innovate the flow field design for optimizing the performance. This paper proposes a new-designed flow field (NDFF) patterned with the built-in blockage and trap-shape rib association. The novel design was analyzed numerically and experimentally. A three-dimensional isothermal numerical model was first established based on COMSOL software. This model demonstrated that the NDFF transformed the traditional diffusion mass transfer into the optimized diffusion and convection mass transfer combination. Compared with the conventional straight flow field, the effective mass transfer coefficient was considerably improved. Moreover, the new-designed structures enforced cyclical variation of local velocity and pressure, forming forced-convection, which was beneficial for water management. At 0.45A·cm−2, the steady-state voltage and the initial dynamic response voltage were increased by 0.08 V and 0.16 V; power density was increased by 20.1%. The experimental results were collected to validate the enhanced performance of PEMFC with the NDFF. Energy efficiency ratio (EER) was proposed as an evaluation criterion; EER results suggested NDFF can improve the net output power. Highlights A new flow field patterned with built-in blockage and trap shape rib association Energy efficiency ratio, effective mass transfer coefficient used for evaluation Steady-state and dynamic performances are greatly improved at an increased Energy efficiency ratio