Working conditions of an Energy Storage System based on a high temperature PEM Fuel Cell

摘要

In this paper, a Fuel Cell based Energy Storage System (FC-ESS) was investigated for enhancing the range of a electrical commuter vehicle. While using a special High Temperature Polymer Electrolyte Membrane (HTPEM) fuel cell with a nominal stack output power of 6 kW, the FC-ESS must be heated up to 120??C. A Fuel Cell Control Unit (FCCU) was created to fulfil the stack working conditions on anode and cathode. To evaluate the system concept a test bench including all required components to run the FC-ESS was built up. Results about the thermal heat up process e.g. a thermal heat up gradient of 2 K/min using a 1.3 kW electric heater integrated in the Tri Ethylene Glycol filled thermal system were obtained. The fuel cell stack polarization curve was measured making a ramp measurement from 10 A to 50 A. Hydrogen purge loss was disclosed between 3???12 % on constant stack electric power set points varying between 1???3 kW leading to an overall measured electric efficiency higher than 46 %. Referring on real traction power demand measurements of a demonstrator car for NEDC, WLTP and a specific commuter cycle between Stuttgart (ST) and Lampoldshausen (LA), the requested hydrogen storage capacity for different working conditions of the FC-ESS was calculated using different power set points. It was shown that a 6 kW FC-ESS with 0.5 kg stored hydrogen mass could extend the range of an FC-ESS equipped electric car up to 200 kilometres on NEDC and 196 km on WLTP. While using different fuel cell power set points commuter test cycle between ST-LA-ST can be driven either driven on the motorway or the freeway using the same hydrogen storage.