Analysis and Improvement of Characterisation Methods for Transport Properties of Gas Diffusion Layers (GDL) for Pemfcs

Target of the presented work is to determine absolute values of GDL parameters with high accuracy, analysing and avoiding error sources caused by both test equipment and measurement methodology to the highest possible extent. The focus is on electrical, thermal and gas transport. Error sources are examined and identified. Specific attention is paid to identify inherent, inevitable measurement uncertainties. As an example, stacking of GDLs as a method to separate the contact and bulk through-plane electrical resistance of the material under compression will be reviewed in detail. In addition, the influence of the sample dimension, the sample orientation and the sample preparation is shown in examples. The results presented are acquired within the project QM-GDL (GDL quality assurance for the market run-up), which is funded by the German Federal Ministry for Digital and Transport under grant agreement number 03B11016C.