Search

Proton exchange membrane (PEM) fuel cell is a promising renewable energy conversion technology due to its many unique advantages. Among its multiple components, flow field plays an important role in distributing reactants from flow channels to electrochemical reaction sites in catalyst layers (CL).Furthermore, since the reactions only occur at the triple-phase boundary regions where electrons, protons and reactants meet, the transport of oxygen affects the electrochemical active area (ECA) available for reaction. Interdigitated flow fields have been shown to be very effective in transporting reactants to the reaction sites in the CL. In this work, interdigitated flow fields with different outlet channel widths are employed to examine their effects on the cell performance and ECA. Experimental results show that with narrower outlet channels both the ECA and the cell performance increase significantly, at the expense of slight increase in the ohmic resistance.

As an extremely important component, flow field plays an important role in a proton exchange membrane (PEM) fuel cell. In this study, a two-dimensional model of interdigitated flow field was developed to simulate the effect of outlet channel width on PEM fuel cell performance using COMSOL Multiphysics, and the simulated results coincided accurately with the experimental results. From the results, the PEM fuel cell performance with narrower outlet channel width was better than that with conventional outlet channel width, since the molarity distribution of oxygen in the porous medium and the electrolyte current density distribution at the membrane cross section were more uniform, and the drainage capacity was stronger. The simulated results have certain reference significance for the design and optimization of interdigitated flow field.

The cathode flow field design of a proton exchange membrane (PEM) fuel cell is essential to fuel cell performance, which directly affects the uniformity of reactant distribution and the ability to remove water. In this paper, the single serpentine flow field design on the cathode side is optimized to reach a high performance by controlling the rib groove rate (the ratio of the number of grooved ribs to the number of total ribs). The rib groove starts from the inlet side and then evenly distributes over the ribs. Four rib groove rates are selected in this study, namely, 0, 1/3, 2/3, and 1. A three-dimensional PEM fuel cell model is used to analyze the output performance of the fuel cell. The results indicate that the rib groove design has a significant effect on the distribution of oxygen at the cathode side, the density of the membrane current, the concentration of water vapor under the rib, and the fuel cell output performance. The output performance of the fuel cell improves with the increased rib groove rate. However, when the rib groove rate is greater than 2/3, its impact on the overall performance of the fuel cell begins to slow down. The PEM fuel cells exhibit the best output performance when the rib groove rate is 1.