Technical University of Munich: Electric trucks: ultra-fast charging in the megawatt range

“Freight transport on our roads is responsible for more than one third of our national greenhouse gas emissions,” says Sebastian Wolff of the TUM Chair of Automotive Technology. Consequently, new truck concepts will be needed if Germany wants to drastically cut its CO2 emissions by 2030.

In the NEFTON project, which is funded by the Federal Ministry of the Economy, engineers working in industry and research are developing a prototype for an electric truck and a charging station to power it.

Rapid implementation of solutions
The first battery-powered truck prototypes are currently being tested with customers serving short-haul routes. A long-haul truck needs to cover 500 kilometers or more in a day, however. That means that the battery would have to be charged at least on a daily basis. That would be a big adjustment for drivers, who currently visit a gas station perhaps once in five days.

Nor is it enough to charge the battery overnight. Consequently, it will have to be possible to charge the battery fairly quickly at various locations over the course of the day – for example when parked at a loading ramp or at special charging stations. This will require adaptations to the infrastructure. “Our goal is to develop solutions that can be implemented quickly and at reasonable cost,” says Wolff. “And do so with technology that is already available – combined in an entirely new way.”

Charging system with a buffer
Ultra-fast battery charging calls for power in the megawatt range. The development of the Megawatt Charging System (MCS) poses several challenges – such as the high cost of a sufficiently powerful grid connection. The solution: Stationary buffer storage to offset the lower power supplied through the grid. Another problem is posed by the batteries in the truck itself, which require efficient cooling to cope with such high power levels.

Different approaches have emerged. “We will probably start with water cooling for the battery, cables and connectors,” says Wolff. But the researchers are also keeping a close eye on developments in battery technology. More efficient batteries could simplify the charging process and thus the cooling.

Sustainable and cost-effective
Another aspect of the new system also promises to promote sustainability and support the energy transition: The chargers are bidirectional. That means that when the trucks are parked for an extended period they can act as storage for renewable energy sources – for example for electricity generated by wind turbines that is not used by households in the nighttime hours. “This concept can be much more attractive and economical than with electric cars, for example, due to the higher storage capacity,” says Wolff.

And what does he expect the electric truck to look like? It will hardly be distinguishable from a current vehicle, he explains, with the biggest innovations to be found under the hood. “We will be presenting innovative solutions over the course of the project. But the advantage of trucks is the modular design. This will allow the series production of the future electric models to take place in the same plants as today’s trucks.”