Influence of wettability on liquid water transport in gas diffusion layer of proton exchange membrane fuel cells (PEMFC)

Hamza Chraibi (1) , L. Ceballos (2) , Marc Prat (1) , Michel Quintard (1) , Alexandre Vabre (2)

1 IMFT - Institut de mécanique des fluides de Toulouse
2 CEA - Commissariat à l'énergie atomique et aux énergies alternatives

Water management is a key factor that limits PEFC's performance. We show how insights into this problem can be gained from pore-scale simulations of water invasion in a model fibrous medium. We explore the influence of contact angle on the water invasion pattern and water saturation at breakthrough and show that a dramatic change in the invasion pattern, from fractal to compact, occurs as the system changes from hydrophobic to hydrophilic. Then, we explore the case of a system of mixed wettability, i.e. containing both hydrophilic and hydrophobic pores. The saturation at breakthrough is studied as a function of the fraction of hydrophilic pores. The results are discussed in relation with the water management problem, the optimal design of a GDL and the fuel cell performance degradation mechanisms. We outline how the study could be extended to 3D systems, notably from binarised images of GDLs obtained by X ray microtomography.

Mots clés: Capillarity; Wettability; Percolation; PEMFC

Domaines: Matière Molle [cond-mat.soft]; Milieux fluides et réactifs

Hamza Chraibi, L. Ceballos, Marc Prat, Michel Quintard, Alexandre Vabre. Influence of wettability on liquid water transport in gas diffusion layer of proton exchange membrane fuel cells (PEMFC). Fundamentals and Developments of Fuel Cells Conference, Dec 2008, Nancy, France. ⟨hal-00416590⟩