author: Eric Walz
The Mercedes-Benz VISION EQXX concept.
Mercedes Benz has demonstrated one of the world’s highest levels of efficiency for an electric vehicle earlier this month. The automaker’s VISION EQXX EV concept traveled 1,000 kilometers (621 miles) on a single charge in an experiment to see how efficient an electric car could become in the future.
It wasn’t just a steady cruise on the highway, The EQXX traveled from Sindelfingen, Germany across the Swiss Alps and into Northern Italy, to its destination in Cassis on the Côte d’Azur in France in everyday traffic situations and varied weather conditions.
Mercedes Benz called the 1,000 km trip on a single charge “a new blueprint for automotive engineering”. The technology that made the trip possible will be deployed in upcoming series-production Mercedes vehicles.
The trip began in cold and rainy conditions. It also included high speed cruising on the German autobahn reaching speeds of 140 km/h (87 mph) as well as slower speeds on other roads. After departing Sindelfingen, temperatures from start to finish ranged from 3 to 18 degrees Celsius (37 – 64°).
North of the Alps, there was light rain and further south the EQXX met with a gentle headwind. The various sections of the route helped Mercedes Benz document the effect of the many efficiency measures engineered into the EQXX.
Once the EQXX reached its destination, the battery’s state of charge was still roughly 15%, which could have allowed the car to travel an additional 140 kilometers, making it the most efficient Mercedes Benz model ever built.
The journey of 1,000 km on a single charge was independently verified. The vehicle’s charging socket was sealed to prevent tampering and accompanied by an independent expert from certification body TÜV Süd.
The long distance trip was made possible by a combination of efficiency measures, everything from the high-efficient powertrain of the EQXX to the vehicle’s aerodynamics helped improve range, according to Mercedes Benz. The EQXX has a drag coefficient of 0.17, which allows its to cut through the wind.
Additional efficiency gains came from the tires. The EQXX was outfitted with low rolling-resistance 20-inch Bridgestone tires developed specifically for the VISION EQXX in partnership with Mercedes-Benz. The tires have a large diameter and a narrow tread.
Bridgestone’s “ENLITEN” tire technology reduces both rolling resistance and weight by up to 20 percent. Even the transition from the tire to the wheel rim was optimized in cooperation with the Mercedes-Benz aerodynamics team to reduce drag.
Another contributor to the EV’s high efficiency is its 100 kWh battery pack. It was developed specifically for the VISION EQXX and has almost the same amount of energy as the battery of the EQS electric sedan. Mercedes-Benz says the battery is 50% less in volume and 30% lighter than a typical EV battery.
The battery also uses what Mercedes calls “active cell balancing”. It ensures that energy is drawn evenly from the cells while driving, which increases the usable energy and therefore bumps up the range.
The electric powertrain of the EQXX was developed in cooperation with the experts from Mercedes-AMG Petronas F1 Team. Mercedes Benz reported an record-breaking efficiency of 8.7 kWh per 100 kilometers for the VISION EQXX.
“We did it! Powering through more than 1,000 kilometers with ease on a single battery charge and a consumption of only 8.7 kWh/100 km in real-world traffic conditions,” says Ola Källenius, Chairman of the Board of Management of Mercedes-Benz Group AG. “The VISION EQXX is the most efficient Mercedes ever built. The technology program behind it marks a milestone in the development of electric vehicles. It underpins our strategic aim to lead in electric.”
The electric drive unit in the VISION EQX consists of the electric motor, transmission and power electronics that delivers a peak output of 180 kW. Like the vehicle’s battery, the electric drive unit is compact, lightweight and highly efficient. Its average efficiency is 95%, meaning that 95% of the energy from the battery ends up at the wheels.
Mercedes-Benz said its engineers have reduced the total efficiency losses in the drivetrain (motor, inverter and transmission) by 44% compared to a typical EV. Mercedes-Benz says that each 1% gain in powertrain efficiency increases range by 2%.
The highly efficient electric powertrain of the EQXX can also recoup more energy from the electronic brakes, which further extends range. The EQXX can use the recuperation effect on any type of gradient and during every braking event.
With electrical resistance stopping the EQXX, the mechanical brakes are barely used, according to Mercedes Benz. This makes it possible to use new types of aluminum brake discs that weigh significantly less than steel brake rotors.
The VISION EQXX also has a solar roof to capture some additional energy. Embedded in the vehicle’s roof are 117 solar cells which feed into the 12-volt battery. It supplies power to the vehicle accessories, such as the navigation system. The solar energy booster increases the range by more than 2%, which is roughly 25 kilometers of additional range on a 1,000 km trip, according to Mercedes-Benz.
The instrument cluster of the EQXX acts as an intelligent co-pilot, providing tips on the best possible driving style to conserve battery power. It provides the driver with information on energy flow, battery status, topography and even the direction and intensity of wind and sun.
The AI-powered user interface of the instrument cluster supports seamless interaction between the driver and the vehicle. The AI that mimics the way the human brain works and reacts instantly to the driver’s needs
In total, the journey on April 5, 2022 included 11 hours and 32 minutes of driving time, with a distance of 1,008 kilometers with a remaining range of around 140 kilometers.
With the experiment, Mercedes-Benz has proven the real-world potential of efficiency possible for future electric vehicles. In addition, future electric vehicles with ranges over 600 miles will lessen the reliance on EV charging infrastructure, which might help boost EV adoption in the future.