Fuel cell powered vehicles do not cause any emissions during operation. Furthermore Hydrogen as a fuel can also be produced emission-free from renewable energies by water electrolysis. However, hydrogen at Hydrogen Refueling Stations – especially if trucked in - can be a mix of different sources and production methods. These different production methods may introduce trace impurities harmful to the fuel cell. The relevant standards for Hydrogen as a fuel therefore define limits for impurities in the range of a few ppm (parts per million). Up to now compliance with these limits can only be checked off-site using expensive laboratory procedures and cannot be monitored onsite.
In project "HAlMa" three different topics concerning fuel quality of Hydrogen are evaluated. In topic three "Hydrogen Quality Sensor" the partners HYDAC and ZeMa are developing a sensor system which monitors the quality of the hydrogen live and onsite at the Hydrogen Refueling Station and detects possible contamination. The aim is to use the sensor in the high-pressure range of hydrogen filling stations for periodic and cost-effective monitoring of hydrogen quality. Shell accompanies these works as an associated partner.
Testing of a hydrogen quality sensor under real conditions
Fraunhofer ISE is responsible for the testing and characterization of the sensor under real life conditions. For this purpose, the prototype of the sensor is installed at the in-house Hydrogen Refueling Station. The sensor is operated and monitored in the regular operation of the refueling station. However, the onsite supply of Hydrogen Refueling Stations with onsite electrolysis cannot cause severe contamination. In order to be able to test the function of the sensor in case of contamination and to validate the function of the sensor, additional measurement campaigns with intentional contamination of the Hydrogen Refueling Station are carried out. Of course, the filling station is not available for refueling during the measuring campaign.
With these tests Fraunhofer ISE is going to validate the sensor under controlled real life conditions and thereby ensures trust in this new approach of live-onsite Hydrogen quality control.
Characterization of contamination effects of PEM fuel cells
Furthermore, Fraunhofer ISE characterizes the effects of contamination in the hydrogen stream by toxic gases or corrosion elements (cations) on the anode and membrane. Therefore, Fraunhofer ISE performs various materials analysis and develops test methods.
Final Report (German Language): Verbundvorhaben "H2- und Kationen-Kontamination: Alterungseffekte, Material- und Sensorenentwicklung" (Halma*), Teilprojekt Kontaminationseffekte