Electric Trucks: On the Road With a Pantograph on the Highway

While electric vehicles with battery storage are on the fast lane in the passenger car sector, manufacturers of trucks and buses are technologically multi-track: They rely on hydrogen-powered fuel cells and battery-powered drive. With battery-powered drive, manufacturers of large vehicles sometimes reach their physical limits. This is especially true for the heavy "e-buses" and "e-trucks" that are not in city traffic, but on longer routes, they need huge battery packs for an acceptable range. This makes the vehicles heavier and a lot of space is needed for large batteries. 

An exciting technological approach is being pursued by a research team from RWTH Aachen University in collaboration with VDI/VDE Innovation + Technik GmbH as a project carrier. The core question is: What if we equipped trucks and buses on the highway with overhead lines and pantographs, like electric trains and electric city buses, to supply electric vehicles with electricity? The "Production Engineering of E-Mobility Components" (PEM) chair has been dealing with this topic for several years.

Trucks with pantographs could cause only half as much CO₂ emissions as conventional trucks 

"The pantograph technology is particularly interesting because the infrastructure for this can be implemented relatively quickly - by 2030 a lot can be achieved. There are studies that show that by using overhead line trucks, around 50 percent of CO₂ emissions can be saved compared to conventional trucks by 2030. If you drive this calculation further and operate the overhead line systems exclusively with renewable energy, the pure operation of these trucks is already CO₂ neutral today," says Simon Dünnwald, PEM group leader.

In September 2017, PEM launched the "LiVe" project, which was funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. At the time, the team equipped a battery-electric vehicle with a "pantograph" - a retractable power pickup mounted on the vehicle. The follow-up project "LiVePLuS" set up in February 2020 now focuses on the drive and power supply of heavy electric trucks and buses.

Pantographs power electric trucks and buses with electricity and charge the battery while driving

With the LiVePluS project, PEM aims to prove that semi-trailer trucks are also suitable for use with a pantograph. To make the electric trucks and buses as flexible as possible, the pantograph can be flexibly folded in and out. The trick: When the vehicle is on a lane with overhead lines, a sensor detects this and the truck's pantograph automatically conforms to the overhead lines. This is called "clamping." This way, the electric motor is supplied with power and the battery is charged at the same time.

Since there are no pantograph trucks that run purely on electricity on German roads yet, the research group could not rely on an existing system. Therefore, PEM looked for an experienced technology partner to convert a truck prototype with an electric motor, a traction battery, and a pantograph as an interface to an overhead line system.

Webasto is the ideal partner for a technologically challenging project

"We had some requirements for the components. For example, we did not want to use prototype batteries, but series-certified batteries that are compatible with the rest of the high-voltage onboard network," explains Konstantin Sasse, PEM group leader. Since space is limited in the truck, the size of the batteries had to fit as well. After intensive market analysis and in-depth research, the choice finally fell on the standard battery system for commercial vehicles from Webasto.

Webasto not only supplied the required components but also supported with a lot of experience and know-how from the electrification of trucks, buses, and large construction machinery. This was appreciated: "We were able to exchange ideas closely with Webasto and had direct contact with all departments. When developing a prototype, very specific questions always arise. The cooperation with Webasto was very close, we received feedback promptly, all relevant data and even support for the commissioning of the individual components on site," says Sasse.

Testing the prototype brings more insights

After numerous tests such as component-specific individual commissioning and commissioning of the overall system in the unbuilt state, the real testing of the prototype is now taking place. For this, the vehicle has already undergone several tests on the RWTH test track. The next step is to test the pantograph on another test track to test the process of clamping to the overhead lines.

Following this, the prototype will be on the road in public traffic. "The goal is to further optimize the system and achieve a higher degree of maturity. This way, we want to reach a point where the modular drivetrain kit is not only mature, but also economically really interesting. If the costs don't work, the system will not be used. But we are on an excellent path."

Electric trucks with pantographs could soon be on public roads 

Infrastructure for a public test run is already being built. Overhead lines have already been installed on sections of the A1 and A9. According to Dünnwald, this is just the beginning: "Simulations and studies indicate that it is enough to retrofit about 30 percent of the German highway network - about 3,200 to 4,000 kilometers - with overhead line systems to electrify 80 percent of heavy trucks. The potential is therefore enormous."

As a technology partner, Webasto will continue to observe and accompany this exciting development. "We are proud to be a partner in a project that is so innovative and has the potential to significantly reduce CO₂ emissions in road traffic. We look forward to continuing to support the project in the future and are always available with products and technical expertise," says Dr. Michael J. Bauer, Vice President Business Line Energy Management at Webasto.