A number of technical and, above all, business-related issues remain outstanding, key among them the range and cost of the batteries, but also the infrastructure required for their use as part of customers’ commercial fleets.

We are now passing both two- and three-axle variants of our heavy-duty electric truck, the Mercedes-Benz eActros, into the hands of customers. Initially the focus will be on inner-city goods transport and delivery services—the ranges required here are well within the scope of our Mercedes-Benz eActros.

We have developed a vehicle that has been configured from the outset for electric mobility. Compared with our prototype, quite a few technical changes have been made: the power supply is now ensured by eleven battery packs in all – and wherever possible we have used already proven components that are ready, or very close to ready, for use in series production.

—Stefan Buchner, Head of Mercedes-Benz Trucks

Participating in the fleet test are ten customers from a variety of sectors in Germany and Switzerland: Dachser, Edeka, Hermes, Kraftverkehr Nagel, Ludwig Meyer, pfenning logistics, TBS Rhein-Neckar and Rigterink from Germany; and Camion Transport and Migros from Switzerland.

These customers all distribute goods via the road network—but in very different sectors and categories. The scope ranges from groceries to building supplies and raw materials. The vehicles are being used by customers for tasks that would otherwise be completed by vehicles with conventional diesel engines. The range of requirements means that the vehicles are fitted with a variety of bodies.

According to need, refrigerated box bodies, tankers or tarpaulin sides are used. The drivers of the eActros are trained specially to work with the vehicle. The pilot customers will be testing the vehicles in real-life operations for twelve months, after which the trucks will be going out to a second round of customers for a further twelve months.

This will enable us to satisfy the many requests we have had from customers and to gain even more insight. Our aim is to achieve series-production and market maturity for a range of economically competitive electric trucks for use in heavy-duty transport operations with effect from 2021.

—Stefan Buchner

The basis for the eActros is provided by the frame of the Actros. Otherwise, however, the vehicle architecture has been configured specifically for an electric drive system, with a high proportion of specific components.

The drive axle is based on the ZF AVE 130 that has already proved its worth as a low-floor portal axle in hybrid and fuel-cell buses from Mercedes-Benz and is now being fundamentally revised for the eActros. The axle housing has been completely redesigned and is mounted in a significantly higher position, thereby increasing the ground clearance to more than 200 mm.

The drive system comprises two electric motors located close to the rear-axle wheel hubs. These three-phase asynchronous motors are liquid-cooled and operate with a nominal voltage of 400 volts. They generate an output of 125 kW each, with maximum torque of 485 N·m each. The gearing ratios convert this into 11,000 N·m each, resulting in driving performance on a par with that of a diesel truck.

The maximum permissible axle load stands at the usual 11.5 tonnes. The energy for a range of up to 200 km is provided by two lithium-ion batteries with an output of 240 kWh. These have already proved their worth in service with EvoBus GmbH – so can no longer be considered as prototypes.

The batteries are accommodated in eleven packs: three of these are located in the frame area, the other eight are to be found underneath. For safety reasons, the battery packs are protected by steel housings. In the event of a collision, the mountings give way and deform, so diverting the energy past the batteries without damaging them.

The high-voltage batteries do not just supply energy to the drive system, but to the vehicle as a whole. Ancillary components such as the air compressor for the braking system, the power steering pump, the compressor for the cab air-conditioning system and, where relevant, the refrigerated body, are also all electrically powered.

Discharged batteries can be fully recharged within three to eleven hours, assuming a realistic charging capacity of 20 to 80 kW from a mobile charging device at a fleet depot. The charging standard used is the Combined Charging System, CCS.

The LV on-board network made up of two conventional 12-volt batteries is charged from the high-voltage batteries via a DC-DC converter. This ensures that all relevant vehicle functions such as lights, indicators, brakes, air suspension systems and cab systems remain operational in the event of the high-voltage network failing or being switched off. The high-voltage network can only be activated if both LV (low-voltage) batteries are charged.

The development and testing of the heavy-duty electric trucks in distribution transport forms part of the project Concept ELV², which is funded to varying extents by Germany’s Federal Ministry for the Environment (BMUB) and Federal Ministry of Economic Affairs and Energy (BMWi) to the tune of around €10 million (US$12.3 million). Areas covered by the funding plan include the investigation of the complex challenges involved in the development, assembly and operation of electric trucks. These include the use of high voltages (> 400 V), high currents (up to 1000 A), battery technology (price, weight, durability, service life, charging time), range and energy requirements, charging infrastructure and logistics concepts, safety requirements, summer and winter viability as well as questions about customer acceptance of the trucks.

The customer innovation fleet will be on the road until at least mid-2020. Its aim is to establish the energy requirements for a series of specific application scenarios as well as the economic efficiency of the electric trucks, and to compare the environmental performance of the electric trucks with that of diesel trucks in a full Life Cycle Assessment. The findings of this research work will find their way back into the vehicles in the form of on-going optimisation measures. The results will be published, giving potential users the opportunity to optimise their route planning or to develop new business models for their logistics processes.