Coupling of a continuum fuel cell model with a discrete liquid water percolation model

The performance of PEM Fuel Cells can be significantly improved by optimizing the liquid water transport capabilities of the porous transport layers (PTLs) to avoid flooding while operating in high humidity. Modelling of the 2-phase water management is therefore of great interest to investigate the influence of the material properties on the fuel cell performance. Compared to continuum models, discrete models, such as pore network models, have significant advantages in capturing the liquid water percolation process observed in the highly porous and hydrophobic components [2]. However, to investigate the influence of design parameters on the fuel cell performance, to date the discrete models have only been applied to estimate effective PTL properties for the continuum models. To improve this coupling and to minimize information loss, a direct integration of a previously presented discrete percolation model [3] in the continuum model is developed in the presented study. Since the input of the discrete percolation model are the PTL design parameters, the coupled model allows to directly analyze the influence of these parameters on the performance. The presented results reveal that the configuration of condensed water under the lands plays an important role for the liquid water transport and the fuel cell performance.