Over the next three years, not only individual components such as solar panel PV modules and power electronics will be developed for this project, but also a manufacturing and production concept that will enable an efficient supply chain between the industries involved. The practical implementation of the prototypes is to take place on an electric truck as a demonstration vehicle.
“On trucks, there is plenty of space in the best sunny position, and with electric propulsion, large batteries are also available – an ideal situation for using photovoltaics to gain valuable on-board energy and thus range, and that 100 percent renewable,” explains Dr. Harry Wirth, Division Manager Photovoltaic Modules and Power Plants at Fraunhofer ISE in Freiburg (Germany).
In the solar roof project, scientists at the lead Fraunhofer ISE are developing lightweight and robust PV modules for two applications: retrofitted on-roof mounting and full integration into the vehicle body. The requirements for the Vehicle Integrated PV (VIPV) modules are demanding: they should achieve a surface utilization factor of more than 90 %, be vibration-resistant, shear and bend resistant and easy to install. In addition, they should have a maximum additional weight of 2.6 kilograms per square meter.
A production concept is being developed for the manufacture of these VIPV lightweight modules in series production and an existing production line of Sunset Energietechnik GmbH is being converted. The module prototypes are integrated into the box bodies of electric commercial vehicles by TBV Kühlfahrzeuge GmbH. Suitable material combinations are tested and a concept for the retrofitting of box bodies including cable routing and the embedding of power electronics is developed.
For the connection of the solar roof modules to the existing electrical bus systems of the commercial vehicle, the project partner M&P motion control and power electronics GmbH develops, tests and certifies the power electronics components for the use on the demonstration vehicles. Due to the limited installation space and the weight requirements, new semiconductor technologies are to be used here, which work with high clock frequencies and therefore can be designed smaller.
The Fraunhofer Institute for Transportation and Infrastructure Systems IVI (Munich, Germany) is developing an energy forecast model of the vehicle, which predicts the range, charging times and power generation for different routes depending on the consumers in the vehicle and the PV power generation.
The demonstration vehicle, a Framo E-truck equipped with solar modules, is being tested in daily distribution operations in the Freiburg area. In a measurement campaign, the irradiation potential of the routes driven is determined; the performance development and stability of the modules under real conditions are also regularly checked.
Finally, the consortium will design a manufacturing process sequence for the economic production of PV-active box bodies and analyse the manufacturing costs as well as the economic efficiency for users.
“We not only want to develop the technology, but also show that trucks can cover over 5 percent of their propulsion energy with solar energy. 4000-6000 kilometres of additional range per year are thus mathematically possible. Vehicle Integrated PV will be worthwhile for manufacturers and operators of solar e-commercial vehicles,” promises Christoph Kutter, project manager at Fraunhofer ISE.
More information: https://www.ise.fraunhofer.de/en.html
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