Heavy-duty all-electric Mercedes-Benz trucks rolling out to customers
Mercedes-Benz Trucks says it's putting its electric truck, the eActros, out on the road with customers. Ten vehicles in two variants, with a gross vehicle weight of 18 or 25 metric tons, will be handed over in the next few weeks to customers who will be testing their everyday feasibility and economic efficiency under real-life conditions. A number of technical and 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.
"Daimler Trucks is synonymous with innovation leadership, allied to a realistic and pragmatic attitude. This is particularly true when it comes to electric mobility. We now want to work together with our customers to move swiftly forward with the development of our Mercedes-Benz eActros to the point where it becomes a viable proposition in tough everyday operations—both technically and commercially. We are beginning this process by creating an innovation fleet and will be supporting its testing in the day-to day logistics environment of our customers. This will enable us to establish just what remains to be done, in terms of technical matters, infrastructure, and service, to make our Mercedes-Benz eActros competitive," explained Martin Daum, the Daimler AG board member responsible for Daimler Trucks and Buses.
"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," added Stefan Buchner, head of Mercedes-Benz Trucks.
Participating in the fleet test are ten customers from a variety of sectors in Germany and Switzerland. The companies are 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 different sectors and categories. 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 to work with the vehicle. The pilot customers will test the vehicles in real-life operations for 12 months, after which the trucks will be going out to a second round of customers for a further 12 months. "This will enable us to satisfy the many requests we have had from customers and to gain even more insight," stated Buchner. "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."
The basis for the eActros is provided by the frame of the Actros. Otherwise, the vehicle architecture was configured for an electric drive system, with a high proportion of specific components. The drive axle is based on the ZF AVE 130 that is employed as a low-floor portal axle in hybrid and fuel-cell buses from Mercedes-Benz and is now revised for the eActros. The axle housing is completely redesigned and mounted in a significantly higher position, which increases the ground clearance to more than 200 mm (7.9 in). The drive system consists of 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 V. 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 par with that of a diesel truck.
The maximum permissible axle load stands at the usual 11.5 metric tons. The energy for a range of up to 200 km (124 mi) is provided by two lithium-ion batteries with an output of 240 kW·h. These have already proven their worth in service with EvoBus GmbH. "Synergies within the Group like these allow us to pool our experiences, shorten development times, and, of course, also save costs," according to Buchner.
The batteries are accommodated in eleven packs: three are located in the frame area and the other eight are 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 to divert 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 3–11 h, assuming a realistic charging capacity of 20–80 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-V 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) with approximately 10 million euros. 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.
Daimler says the customer innovation fleet will be on the road until at least mid-2020. The aim for the fleet is to establish the energy requirements for a series of 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 will be fed back into the vehicles as ongoing optimization measures. The results will be published, giving potential users the opportunity to optimize their route planning or to develop new business models for their logistics processes.