Integrated with a 3.5 kW high-voltage solar PV system and a 800 V traction battery, a heavy-duty electric vehicle has secured approval to ply on the road in Germany, said Fraunhofer Institute for Solar Energy Systems (ISE). The commercial truck has cleared technical inspection which the institute said marks a milestone towards more climate friendly road freight transport.

Technology services company Alexander Bürkle GmbH will now ply the demonstrator vehicle on Freiburg roads daily. To check operational efficacy and components under real conditions, the truck’s performance will be regularly tested daily for a year to validate electricity yield forecast.

Developed by the institute along with the Fraunhofer Institute for Transportation and Infrastructure Systems IVI and other industry partners, the solar system of the 18 ton truck can generate 5% to 10% of its electricity requirements. Power generated by the panels is fed directly into the on-board power supply of the vehicle.

While the German institute developed lightweight PV module prototypes for this Lade-PV project, these were built by Sunset Energietechnik GmbH, and integrated into the box body of the Framo electric truck by TBV Kühlfahrzeuge GmbH.

It is equipped with Fraunhofer ISE’s energy forecast model IVImon system to enable forecasting the range, changing times, and power generation for different routes depending on the vehicle’s consumption and solar radiation.

Fraunhofer ISE has also developed a separation device in the junction box of each PV module that can prevent the risk of high voltages since the modules are connected. Engineers explain that in case of an accident, the device disconnects the power within milliseconds to ensure ‘only harmless, low protective voltages’ are present in the system.

“By successfully putting our high-voltage photovoltaic system into operation, we have achieved our goal of demonstrating the feasibility of vehicle-integrated photovoltaics for heavy-duty electric utility vehicles,” said Fraunhofer ISE Project Manager Christoph Kutter. “The technical components integrated into the truck function as we expected.”

The truck has also been equipped with a DC power controller from project partner M&P Motion Control and Power Electronics GmbH to communicate with the vehicle control system.