Measurement of flooding in gas diffusion layers of polymer electrolyte fuel cells with conventional flow field

The objective of this work is to clarify the location and magnitude of flooding in polymer electrolyte fuel cells with a conventional flow field experimentally and by a numerical calculation. In the experiment, a newly developed cell with a conventional, interdigitated-switchable gas-flow field was used and the pressure drop between the inlet and outlet of the cathode was measured with the interdigitated flow field after the cell was operated with the conventional flow field. Significant pressure drop was observed after high current densities were flown; the pressure drop indicates the flooding level in a gas diffusion layer (GDL) during the conventional flow field operation. The cell performance and the flooding behavior depended significantly on wetting properties of catalyst layers and GDLs. In the simulation, liquid water distribution in the cathode GDL was predicted using a two-phase model, and validated by comparing the pressure drop measured and calculated using a gas-flow model. The simulation results agreed well with experimental data at high humidity condition and showed that a large amount of liquid water exists in the cathode GDL at high current densities.