<i>In situ</i> Synchrotron X‐ray Radiography Investigations of Water Transport in PEM Fuel Cells

Abstract

Abstract Water transport in an operating PEM fuel cell was investigated with synchrotron X‐ray radiography with a spatial resolution of 3 μm and a temporal resolution of 5 s. This method allows for the detection of water accumulations with less than 10 μm diameter. We demonstrate that synchrotron X‐ray imaging can dramatically expand the possibilities of imaging with high spatial and time resolution, especially as a complement to neutron radiography. Water transport processes from the first appearance of small water accumulations in the gas diffusion layer to their transport into the channel system were analysed in situ . Correlations between local effects such as water formation and operating conditions of the whole system, e.g. power variations, were found. A recently described eruptive water transport mechanism is analysed in detail.