Experimental study of water transport in gas diffusion layer of PEMFC considering the phase-change-induced flow

Abstract

The phase-change-induced (PCI) flow triggered by the non-isothermal effect complicates the water transport process in the gas diffusion layer (GDL). So far, studies on the PCI flow in GDL are still scarce. Particularly, the correlation between the PCI flow and the dynamic liquid water behaviors on the GDL surface needs to be further revealed. In this study, an ex-situ visualization setup was developed to investigate the water transport behaviors of the GDL with varied temperatures. The results indicate that low-temperature conditions (<40 °C) are beneficial for the stable liquid water transport, and liquid water breaks through at a specific main emerging position (MEP). However, elevating the temperature to 60 °C increases the condensation droplets and causes the “incubation period”, resulting in the MEP no longer being fixed. Besides, an increase of temperature difference (TD) across the GDL also leads to more water emerging positions on the GDL surface. Compared with the isothermal case, the “incubation period” in the non-isothermal condition lengthens. The PCI flow could also facilitate effective heat removal at high temperatures. This work aims to offer valuable references for understanding the role of PCI flow in the water and thermal management of PEMFC.