Heavy goods vehicles (HGVs) and trucks account or a large proportion of CO2 emissions, which is why the EU has imposed strict targets to “clean up” long distance freight. The problem is, electric drives have proved difficult to implement and uneconomical for long distance transporters, due to the high mass and cost of such batteries. A joint research project between two Fraunhofer institutes and the TU Darmstadt (funded by the German Federal Ministry for Economic Affairs and Energy) set out to solve this problem by developing alternative drives. The result is the evTrailer: a lightweight, high-voltage energy storage system which is self-sufficient.
The Fraunhofer Institute for Structural Durability and System Reliability (LBF) was able to achieve the necessary voltage (total capacity 100 kilowatt hours and a voltage range from 590 – 670) by harnessing the power of 10,000 cells linked by specialised current connectors, using a novel lithium metal oxide cathode material. The LBF managed to keep the total weight of the system – including the cooling system, casing and battery management system – to less than 600 kilograms. The housing concept used sandwich structures and glass fibre-reinforced thermoplastics. "With such an ultra-lightweight construction solution for a high-voltage energy storage system, concepts such as the evTrailer are possible and develop perspectives for achieving the CO2 reduction targets in freight transport," explains Rüdiger Heim, project leader at the LBF, in a . The evTrailer has its own sensing and control technology which means it can be manoeuvred easily and independently, for example at a logistics centre. In tests, the evTrailer was able to reduce the overall consumption of the HGV by 20 percent over long distances.