Contact pressure in the proton exchange membrane fuel cell: Development of analytical models based on experimental investigation and a posteriori design of experiments

To understand the link between the physical properties of the Gas Diffusion Layer (GDL) and the overall performance of a Proton Exchange Membrane Fuel Cell (PEMFC), it is essential to investigate the impact of compressive loading on the physical parameters of the component, focusing on its electrical properties. This paper's experimental results obtained in the team’s previous research are classified and analysed using a posteriori Design of Experiment (DoE). It allows us to determine the influential parameters on the component behaviour. Two analytical models are developed through regression analysis, allowing for predicting the output variables as a function of the input ones. The results are evaluated with statistical tools. The first model predicts the electrical Contact Resistance (CR) variation of the GDL as a function of mechanical compression and component type. The analytical results show that cycling compression has a negligible effect due to the lower number of applied cycles. The Micro Porous Layer (MPL) presence increases the CR, while the polytetrafluorethylene (PTFE) decreases it slightly. The GDL thickness is the most influential geometrical parameter. For this reason, a second analytical model is developed and predicts that CR is reduced primarily by increased mechanical compression and thicker GDLs.