Microscopic Observation of Freezing Phenomena in PEM Fuel Cell at

In Polymer electrolyte membrane fuel cells (PEMFCs) below zero, the freezing of product water induces the extreme deterioration of cell performance. This phenomenon is serious problem in cold regions and is needed to be solved to achieve the practical use of PEMFC. In this study, we investigate ice distribution in the catalyst layer (CL) and gas diffusion layer (GDL) using an optical microscope and a CRYO-SEM to clarify the freezing mechanism. The effects of the start-up condition such as the current density on the ice distribution and cell performance in a fuel cell are discussed. Experiments were divided into two processes. One is the cold start in a thermostatic chamber and another is the observation in the chamber or a CRYO-SEM unit.