Vision EQXX showcases ultra-efficient battery technology, world-class aerodynamic design, sustainable interior materials and cross-company working methods.
This concept car gives us a glimpse into what the next generation of Mercedes electric cars will look like. It was conceived as a pure electric vehicle at the beginning of the project, and many of the traditional elements that have determined the size, shape and structure of many models from EQA to EQS have disappeared.
Instead, the Vision EQXX is a relatively light, simple compact car that was developed with a focus on efficiency. For the driver, efficiency is reflected in a long range – around 960 km – and a new cab. Its innovations include a lightweight, compact and efficient battery pack, Mercedes-Benz's lowest wind resistance coefficient ever, clever battery cooling system, solar panels, eco-friendly materials, and more.
Solar cells on the roof power the auxiliary system.
Models that inspired it during development include Mercedes' own AMG Project One (which provides a power control electronic unit), the GM EV1 (one of the pioneers of electric vehicles, but unfortunately not long-lived) and Volkswagen's environmental champion XL1. Mercedes' Formula One and Formula E teams are both directly involved in the project.
In fact, the previous statement that the Vision EQXX is a concept car is not entirely correct, because it does preview a specific production model. It focuses on certain possibilities in terms of technology, styling, user experience, etc., as well as the creative process related to mercedes models in the near future.
The project was completed in just 18 months, and was affected by the pandemic, and the participants included Mercedes' teams in Germany, India, the United States and the United Kingdom, while also leveraging the expertise of several external startups. We know from several insiders at Mercedes that the reason the whole project went so quickly and efficiently was that the initial idea was so clear – what it should be and what it shouldn't be was just as clear.
The car's target was not the Nürburgring
Once lap goals are set aside, engineers can focus on achieving the optimal combination of efficiency, energy density and low weight when developing the powertrain. Mercedes says the car is 95 percent efficient, meaning 95 percent of the battery energy reaches the wheels, and 30 percent is a good result for the internal combustion engine.
One way to achieve such high efficiency is to minimize system losses, as the collaborator is Mercedes's F1 engine manufacturer, Brixworth-based High Performance Powertrain (HPP). Eva Greiner, the company's chief engineer for electric drive systems, told us: "One of the best ways to maximize efficiency is to minimize losses. We work in every part of the system to reduce energy consumption and loss through system design, material selection, lubrication and thermal management. ”
The power electronic control unit is based on the control unit on the upcoming Mercedes-AMG Project One top-of-the-line sports car and features the use of a new generation of silicon carbide. But unlike the hybrid that exceeded 1,000 horsepower, the EQXX had a maximum power of only 204 horsepower, and the energy source was a battery with a net capacity of less than 100 kilowatt-hours. Considering that the car weighs less than 1750 kg, it should not be particularly slow, but its primary goal is endurance.
The efficiency of the electric drive means that it does not require a large cooling system.
Putting aside high cornering speeds eliminates the need for bulky, high-performance suspension or brakes. The cooling system can also be super simple: the high efficiency of the electric drive means that it generates very little waste heat, so there is no need for a large cooling system. A heat sink on the floor takes advantage of the heat dissipation properties of the air flowing underneath the vehicle in motion, and most of the rest of the cooling tasks are done part-time through aerodynamically designed ventilation holes. When part-time is not required, they remain off, improving aerodynamics, which in turn reduces the need for drives.
It doesn't have to wait for infrastructure improvements
Mercedes believes they have created an electric vehicle equivalent to the "1-liter car" that exists in the world of internal combustion engine models. (A brief review: In the age of fossil fuels, the sacred goal of environmentally conscious depots is to run 100 kilometers with only 1 liter of oil.) The Vision EQXX uses less than 10 kilowatt-hours of electricity for 100 kilometers, which is equivalent to 1 liter of fuel according to Mercedes' calculations.
The most striking thing in the cab is the one-piece 47.5-inch screen.
Adam Allsopp, HPP's director of advanced technology, said the EQXX's battery energy is almost the same compared to the large sedan EQS, but it is only half the size and 30% lighter. "Battery management systems and power electronic controls are designed with an absolute focus on minimizing losses. We learned a lot in achieving this efficiency milestone that will be applied to future development projects. ”
Part of the increase in energy density is due to the use of high levels of silicon at the anode. The battery team also studied exceptionally high voltages, collected data from experiments using more than 900 volts, and are currently weighing the pros and cons.
The battery employs active cell balancing technology, which extracts energy from each cell evenly to help improve endurance. The battery housing, designed jointly by HPP and the F1 team's chassis division, is made from a sustainable composite material extracted from sugarcane waste and reinforced with carbon fiber.
The wheelbase is between Class A and Class C,
But it weighs more than both cars.
There are 117 solar cells on the roof, which are able to power some auxiliary systems, thus reducing the consumption of the main battery. Under ideal conditions, it could increase the mileage by about 24 km. The project team is currently working on how to use solar energy to charge the high-voltage system.
It's not heavy (by electric vehicle standards)
There is no motor on the front axle, only one on the rear axle. The chassis was also minimized, and the design principle was to use only the load-bearing materials where necessary. Engineers used polygon modeling tools in the video game industry to determine stress and load paths in virtual components. Using this data, some parts can be cast into a mesh, i.e. a thin cavity where strength is not required. The bodywork is made of steel plates made of scrap metal, while several doors are made of carbon fiber, glass fiber and aluminum.
It is not afraid to break with tradition
The cab uses a combination of recycled, sustainable and artificially created materials. The door pull ring is made of a silk-like artificial fabric, while some of the seemingly leather decorative pieces are actually made from materials extracted from mushroom or cactus pulp. Carpets are made of fast-growing bamboo, while other places use materials made from recycled plastic bottles and landfill waste.
Knowing that the car's goal was efficiency rather than racetrack passion, Mercedes discarded the usual elements of a sports car in its design and found new ways to give the EQXX good aerodynamics: the drag coefficient was as low as a staggering 0.18, thanks to the low nose, deformable rear diffuser and narrow rear track.
The Vision EQXX's styling is very distinctive, but Mercedes firmly says that this is just a "by-product" of the pursuit of efficiency. This year it will begin testing on public roads.
Which cars contributed inspiration to EQXX?
Volkswagen XL1
The plug-in hybrid, born in 2013, is designed to travel 100 kilometers with 1 liter of diesel. Both its appearance and ambition inspired the Team at Mercedes.
Mercedes 540 K Streamliner
Produced in 1938 to test tires at high speeds on unrestricted highways, it also proved the value of a wind tunnel.
Mercedes C111
A wedge sports car from the late 1960s to the early 1970s, actually produced as a testbed for rotor engines, shows how low the front can be.
Mercedes IAA concept car
EQXX draws on the rear of the 2015 show car, and for maximum aerodynamic benefits, the rear of the car changes shape at a speed of 80 km/h.
Text/Colin Overland Translation/Shang Hongxin