First Premiere of 2022: Mercedes-Benz Vision EQXX
We have before us "the most efficient Mercedes ever built." This is not some pretty cool production Mercedes EQS or EQE electric car, but a completely original development. A sort of manifesto for the electric mobility division of Mercedes-EQ, designed to show the direction of development of the company’s battery models.
The Vision EQXX project started just a year and a half ago. The main goal of the developers was to create an electric vehicle capable of driving 1000 km on a single charge of the traction battery. Energy consumption must be less than 10 kWh per 100 km. And it should not be a small and light body on bicycle wheels, but a “normal" car with a four-door body and a full interior. The concept is about five meters long, but the wheelbase (2800 mm) is shorter than that of the new production C-Class.
One of the main keys to solving this problem is aerodynamics. Mercedes-Benz Vision EQXX has a very low drag coefficient Cd: only 0.17 versus 0.20 for production Mercedes EQS. At the same time, it is important that the Vision EQXX does not have moving aerodynamic elements and cannot even change the ground clearance, pressing on the road at high speed.
To improve aerodynamics, a silhouette with a long rear overhang of the tail works, which “calms” the air flow coming from the roof. In addition, the body of the machine tapers towards the stern, imitating the shape of a cliff: the rear track is 50 mm narrower than the front. The concept has a smaller front projection area than the Mercedes CLA compact sedan. Of course, mirrors, underbody, wheels and other important elements have been optimized in terms of aerodynamics.
The second way to improve energy efficiency is to reduce the weight of the machine. And the Mercedes engineers have done a lot of work here too. The body is mostly made of ultra-high strength steel, but the doors are made of aluminum-reinforced carbon fiber and fiberglass, and the other 42 parts are made of UBQ composite material. Designed by Israeli company UBQ Materials, it uses recyclable materials and is 15-20% lighter than conventional parts.
And the main subject of body art is a huge rear stretcher with a separate name BIONEQXX. It is completely cast in aluminum and has a perforated design with "holes" in the discharge areas. The front suspension strut mounts are designed and manufactured according to the same principle. By the way, the suspension itself uses fiberglass-reinforced composite springs – they were developed in collaboration with Rheinmetall Automotive and are lighter than traditional steel ones. And the brake discs are made of aluminum alloy. In this context, 20-inch magnesium wheels are no longer surprising.
The concept is based on the promising MMA (Mercedes-Benz Modular Architecture) modular platform, and experts from the Mercedes-Benz F1 High Performance Powertrain racing division were involved in its development. The concept is unsurprising for its weight/power ratio and dynamics: a single electric motor with 204 hp is installed on the rear axle. But it is claimed that the efficiency of the electric drive (“from the battery to the wheels”) reaches 95%. Although for production Tesla models, this figure is 90-93%.
The "nearly 100 kWh" traction battery is twice as compact (mainly due to thickness) and 30% lighter than that of the Mercedes EQS series electric vehicle. The developers do not reveal all the secrets, but the high energy intensity of 400 W ∙ h / l was achieved, among other things, thanks to new anodes with a high silicon content. The operating voltage of the electrical system is 900 volts versus 400 volts for the EQS model, which has reduced the size and weight of the power wiring (although Porsche and Audi already have an 800 volt electrical system as standard). In addition, all control electronics are "packed" into one OneBox, which is located directly above the battery, which reduces the number of wires. The total weight of the battery with this module is 495 kg.
The new battery heats up less than the existing batteries, and this has simplified the thermal management system. Under the bottom, heat is removed through the battery casing, there is an additional heat exchanger, and if their efficiency is not enough, the electronics will open the blinds in the front of the car for additional air flow. At the same time, open shutters increase the drag coefficient Cd by only 0.007.
The panoramic roof and rear window are replaced by a solar panel developed in collaboration with Solar Energy Systems ISE and the Fraunhofer Institute. It consists of 117 cells and under ideal conditions (for example, in sunny weather) is able to increase the range of an electric vehicle by 25 km per day. True, this is a calculated indicator, because the charge of the solar battery does not go to the electric motors. It is stored in a separate lithium iron phosphate battery and is used to power secondary systems such as air conditioning, headlights or multimedia systems. But the charge of the main traction battery saved in this way will allow you to drive the same 25 km.
The concept has other promising features as well. For example, this is a full-size screen on the front panel. And if the production Mercedes EQS has such a Hyperscreen, which actually consists of three separate displays, then there really is one screen with a diagonal of 47.5 inches with a resolution of 8K. The multimedia system itself with the beginnings of artificial intelligence was developed in collaboration with the Californian company BrainChip.
There is a projection screen, the interior is made of recycled materials and using plant materials, including bamboo and cactus. And here, engineers have found ways to reduce weight a bit. For example, the speakers of the speaker system are placed as close as possible to the ears of bikers, which reduced their power and size.
As a result, the Mercedes-Benz Vision EQXX weighs only 1,750 kg. For such an electric vehicle, this is truly an outstanding achievement. For example, the serial BMW i4 liftback, even in the basic version with an 81 kWh battery and rear-wheel drive, pulls 2.1 tons, and the aforementioned Mercedes EQS weighs at least 2.4 tons. And the developers promise that the Vision EQXX will really be able to drive 1000 km without recharging. But the actual mileage remains to be seen as only virtual tests have been conducted so far. That is, before the application of all the technologies described on the serial Mercedes, it is still far away.