Measurements in the Recirculation Path of a Fuel Cell System

When using "green" hydrogen, fuel cell technology plays a key role in emission-free mobility. A powertrain based on fuel cells (FC) shows its advantages over battery-electric powertrains when the requirement profile primarily demands high performance over a longer period of time, high flexible availability and short refueling times. In addition, FC achieves higher effi-ciencies than the combustion of hydrogen in a gas engine, meaning that the chemical energy is used more efficiently than with established combustion engines. When using FC technology, numerous companies in Baden-Württemberg can contribute their specific expertise from the traditional automotive construction and supplier business. This includes auxiliary units in the air (cathode) and hydrogen (anode) path, such as the air compressor, the H2 recycling pump, humidifier, cooling system, power electronics, valve and pressure tank technology as well as components of the fuel cell stack itself. The periphery of the media paths plays an important role in the service life of the fuel cell stack, the costs and weight of the overall system and the overall efficiency "from tank to wheel". Based on measurements on a fuel cell system test bench, which corresponds to a fully functional system with all peripheral components, the dependencies of the hydrogen consumption on the recirculation strategy and the purge strategy are presented using the polarization curve and other measurement parameters such as the hydrogen pressure on the anode side, the hydrogen concentration etc.