New Upscaled Equations for the Reliable and Efficient Catalyst Layer Modelling in PEM Fuel Cells

Recently, we derived a rigorous macroscopic model for a porous catalyst layer in a PEM fuel cell [1,2]. Starting from a microscopic description, it accounts for the oxygen reduction reaction in periodically distributed pores, filled with liquid water. We now present first computational investigations of the newly derived macroscopic transport equations, which rely on characteristic porous media (corrector) tensors, Darcy's law and an effective Butler-Volmer equation. This macroscopic formulation is inherently linked to the dynamics at the microscale and it can be computed in a fairly straightforward manner under the assumption of local thermodynamic equilibrium. Our computational results demonstrate that this upscaling provides a convenient and efficient computational framework for the numerical investigation of optimal catalyst layer designs.

[1] M. Schmuck and P. Berg, Homogenization of a catalyst layer model for periodically distributed pore geometries in PEM fuel cells, Appl. Math. Res. Express. 2013(1):57-78 (2013).

[2] M. Schmuck and P. Berg, Effective macroscopic equations for species transport and reactions in porous catalyst layers, J. Electrochem. Soc. 161(8): E3323-E3327 (2014).