Mercedes has put its prototype EQXX on the road, to prove that the one-off (so far) electric car really can squeeze out 1,000km from a single charge of its battery. And, according to Mercedes, it has done just that. Travelling from Sindelfingen across the Swiss Alps and Northern Italy to its destination of Cassis on the Côte d’Azur, Mercedes says that the EQXX “effortlessly covered more than 1,000 km in everyday traffic, on a single battery charge.” The final tally was actually 1,008km, covered in 11 hours and 32 minutes.
High-speed cruising
The EQXX left Stuttgart in cold and damp conditions, and Mercedes says that it cruised at 140km/h on the Autobahn sections of the journey, and ran either at or close to the local speed limit elsewhere. On arrival in Cassis, there was still a 15 per cent charge left in the battery, which amounts to around 140km of range. That equates to average electric consumption of 8.7kWh/100km. For reference, the best on-sale EVs at the moment average more like 16-17kWh/100km. Mercedes was actually pretty strict on itself with this test - the EQXX’s charging socket was actually sealed up, and certified by an official from the TÜV (Germany’s equivalent of the Institute of Mechanical Engineers). “We did it! Powering through more than 1,000 kilometres with ease on a single battery charge and a consumption of only 8.7 kWh/100km in real-world traffic conditions. The Vision EQXX is the most efficient Mercedes ever built. The technology programme behind it marks a milestone in the development of electric vehicles. It underpins our strategic aim to ‘Lead in Electric’,” said Ola Källenius, Chairman of the Board of Management of Mercedes-Benz Group AG.
Extending bodywork
The route took in motorways, city streets, country roads, and even Alpine passes, with temperatures ranging from 3 to 18 degrees Celsius. It’s the EQXX’s clever aerodynamics that gives it such a long-legged range, according to Mercedes engineers. For a start, it has an incredibly low coefficient of drag - just 0.17Cd, and a small frontal area of 2.12 metres square. The fact that the rear track is narrower than the front, by 50mm, plays a part too as it means that the rear wheels effectively roll along inside the aerodynamic wake of the fronts. Plus, the EQXX even has moveable bodywork - the rear of the car extends at speed, forming a teardrop shape which makes it even more aerodynamically efficient. It also uses specially designed Bridgestone Turanza Eco tyres with an exceptionally low level of rolling resistance. It helps, too, that the EQXX is very light. It uses sustainable carbon-fibre-sugar composite material used for the upper part of the battery, which is also used in Formula 1, and the ‘BIONEQXXTM’ rear floor, manufactured using an aluminium casting process. The light metal structural component replaces a much heavier assembly of several interconnected parts. It has gaps in places where structural strength is not required, thus saving material. This innovative design approach results in a weight saving of up to 20 per cent compared to a conventionally manufactured component. The battery is pretty clever, too. At 100kWh capacity, it’s about as powerful as that used by the production EQS saloon, but the battery pack itself is 30 per cent lighter and takes up 50 per cent less space than that of the EQS. The electric drive was developed in cooperation with the experts from Mercedes-AMG Petronas F1 Team.
Solar panel
That’s not all - the EQXX’s roof is a big solar panel, which Mercedes reckons added an extra 25km worth of range during the journey, once the weather brightened up south of the Alps. “With our successful road trip to the South of France, we’ve shown that efficiency is the new currency. And this success also clearly speaks for our new collaborative development process, incorporating many learnings from the Mercedes-AMG F1 team and its cutting-edge expertise in electric powertrains. The Vision EQXX is the result of a comprehensive programme that provides a blueprint for the future of automotive engineering. Many of the innovative developments are already being integrated into production, some of them in the next generation of modular architecture for compact and midsize Mercedes‑Benz vehicles. And the journey continues. With the VISION EQXX, we will keep testing the limits of what’s possible,” said Markus Schäfer, Member of the Board of Management of Mercedes-Benz Group AG, Chief Technology Officer responsible for Development and Purchasing.