Influence of the Clamping Force and the Formation of Liquid Water Along the Channel on the Local Diffusion Processes in PEMFCs

A novel measurement setup, technique, and segmented model are introduced to spatially resolve mass transport losses along the channel in a PEMFC. The newly designed segmented cell enables not only the measurement of local current and voltage data but also the capture of local temperature and compression levels. By extending the commonly used limiting current method, the local mass transport resistance is determined as a function of local operating parameters. The local current and temperature are directly measured, while the operating conditions along the channel such as pressure, oxygen fraction, and relative humidity are obtained empirically from a 1-D differential model. Leveraging both measured and empirically-based simulation results, this comprehensive approach facilitates the characterization of mass transport resistance distribution along the gas channel. The learnings from this study provide valuable insight into the optimization of channel and materials design for enhancing large active area fuel cell performance and durability.