In-situ visualization of cathode flow channel in polymer electrolyte membrane fuel cell: Effect of GDL degradation

Abstract

Polymer electrolyte membrane fuel cells (PEMFCs) are used in various fields, but their lifetime should be considered for commercial applications. The degradation of their gas diffusion layer (GDL), which enables fuel diffusion and water management, can reduce the performance and accelerate the degradation of other components. This study investigates the effect of GDL degradation on in-situ flow characteristics in cathode flow channels. A special cell is designed to visualize in-situ two-phase flows in the cathode flow channel with a high-speed camera. As the GDL degrades, the flow pattern changes from dropwise to slug and annular flows. Moreover, the amount of residual liquid after one water discharge cycle increases as the GDL deteriorates. These changes in the flow patterns and remaining liquid can disrupt the fuel supply to chemical reaction sites and degrade PEMFC performance.