Enhanced performance in proton exchange membrane fuel cell with the twisted parallel micro-channel for flow field

The mass transfer efficiency of reaction gas in proton exchange membrane fuel cells (PEMFC) has a great impact on its performance, and the flow field is another important factor affecting the mass transfer performance. A kind of twisted parallel flow field (TPFF) with parallelogram equal cross-sectional area and gradually changing shape along the gas flow direction is presented in this paper. The position of each vertex of a parallelogram changes as a sinusoidal function along the flow direction. The output power density, oxygen concentration, current density, gas flow velocity, and water saturation were compared between TPFF and conventional parallel flow field (CPFF). According to the research results, the gas flow velocity of TPFF is greater than that of CPFF at Channel-GDL interface, the channel is higher than that of the CPFF, which can effectively alleviate flooding. Oxygen is more easily diffused from the bulk phase to the membrane electrode due to the decrease of the mass transfer impedance of oxygen in the TPFF. The oxygen content in membrane electrode is higher than CPFF when the fuel cell operates in the diffusion-polarized zone. Compared with the CPFF, the TPFF fuel cell has better output performance, and the maximum output power is increased by 8%. In addition, due to increasing oxygen transmission efficiency, the uniformity of the reaction is enhanced, so that the low current density region is controlled and the uniformity is improved.