The first part will briefly describe the main activities performed in the frame of hydrogen activities at CEA (modeling, manufacturing, characterization and testing) with a focus on PEMFC.
The second part will focus on results obtained to analyze fluid & charge transfers and water management during the operation of PEMFC. This section will include results from the characterization of the gas diffusion layer (GDL) (transfers, wettability); local instrumentation between rib and channel throughout the thickness of the MEA (electrical potential, temperature) and visualization of droplets on the surface of the GDL and analysis of water in membranes using small angle neutron scattering (SANS).
The third part will present Pore Network Modeling (PNM) applied to PEMFC to try and link local properties of materials to the performance of PEMFC. A description of the method will be presented along with results for the MEA and its constituent parts: the GDL, micro porous layer (MPL) and active layer (AL).
PNM results on the analysis of two-phase transfers inside GDL, will provide insight into the influence of wettability and thickness, and the validity of classical Darçy models. Coupling of PNM and performance models to allow analysis of the degradation of PEMFC as a function of the loss of hydrophobicity of the GDL will also be presented. A discussion on the influence of the coupling of different layers of the MEA will highlight the role of the MPL (two-phase filter, injection points and breakthrough points) helping better understand water management inside the MEA.
Finally it will be shown how results from PNM can be extended to use for the AL by coupling two-phase transfers to charge transfers.
Joël Pauchet has worked on hydrodynamic effects at Alstom for several years (turbulence, cavitation, design of foils…) using various modeling and experimental tools. Then he was in charge at CNES (French National Space Center) of the development of the Ariane 5 upper stage propulsion system. He joined CEA in 2000 where he developed the activity of two-phase analysis in PEMFC (modeling, visualization, characterization, local instrumentation…).
He has supervised numerous PhD or post-doctoral students and is involved or coordinates several French and European projects.