The Mercedes-Benz Vision EQXX Is More Important Than You Think
Range through efficiency
There’s no doubt that we’re in the midst of one of the automotive world’s greatest evolutions since the advent of Ford’s mass production assembly lines back in the 1920s. Whether petrolheads like it or not, the EV wave is coming and competition is only heating up between automakers. With Tesla disrupting the market and claiming initial dominance in the EV sector, it was only a matter of time until newcomers like Lucid Motors brought compelling alternatives to Elon Musk’s tongue-in-cheek S3XY lineup.
Legacy automakers weren’t going to just sit back and let the new guys have all the fun though. Widely regarded as creator of the first automobile, Mercedes-Benz has just revealed their vision for the future of electric cars, aptly named the Vision EQXX.
Melding traditional sports car concepts of lightness and trick aero with next generation technologies, the Vision EQXX is meant to be a sort of playing ground for Mercedes-Benz. Touting a 620 mile range may not seem outlandish considering the pack-leading Lucid Air Grand Touring is able to achieve 516 miles in production form (read: not a concept); but the Vision EQXX is able to do so with a battery that holds just under 100 kWh in capacity. Compared to the Lucid Air’s 118 kWh battery pack, the EQXX is nearly 30% more efficient (and about 53% more efficient than the Tesla Model S Long Range!). That being said, the EQXX only produces 201 hp and is limited to an 87 mph top speed – a sizable difference from Lucid and Tesla’s high horsepower offerings.
The technology used in the Vision EQXX program draws engineering prowess not only from the Mercedes Formula 1 and Formula E programs, but from a variety of start-ups and companies experimenting with advanced systems and processes. Some of this technology will make its way to road-going cars within the decade, so let’s take a peak at what the future has in store for our four-wheeled friends.
Less bad is good
Eva Greiner, chief engineer of Mercedes-Benz’s electric drive system, explains that “one of the best ways to improve efficiency is to reduce losses.” Easier said than done. The approach Mercedes-Benz took with the Vision EQXX was to tackle inefficiencies at all facets of engineering and design. Greiner continues, “We worked on every part of the system to reduce energy consumption and losses through system design, material selection, lubrication, and heat management.” The result of all those efforts is a car that boasts 95% efficiency from battery to wheels! For comparison’s sake, the most efficient modern internal combustion engine drivetrains have about 40% efficiency – the rest of the 60% energy is lost in heat and friction.
The obvious solution to increasing range would be to add more batteries, but that also increases weight (and reduces efficiency). Besides, Mercedes wanted the EQXX to be compact. The battery pack in the Vision EQXX has an energy density close to 400 Wh/l -holding nearly 100 kWh of energy, but half the size and 30% lighter than the battery pack found in the EQS. Integrating the battery pack into the specially designed platform helped increase energy density and reduce weight of the overall package. The batteries “speak” to a separate compartment housing the brains, called the OneBox, which utilizes super efficient operations and safety devices to manage the 900-volt architecture.
To cool everything, the EQXX has a trick array of aero-shutters, coolant valves, and water pumps – essentially a next-gen active air-flow management system utilizing a cooling plate on the floor – to keep the electric drive unit from frying itself. Only during spirited driving or hot ambient temperatures will the car’s aero adjust its shutters to let in air, otherwise they’re shut (and decreasing drag). The result is a system that’s fully integrated, efficiently managed, and effectively cooled (air-cooled!). Mercedes-Benz says the active shutter system adds about 12 miles (20 km) of range when closed. Every little bit counts!
Speaking of heat, a major power draw for EVs is generating cabin heat in colder climates. While we’ve described the efficiency of the Vision EQXX’s electric drive unit up until now, it naturally still generates heat. This heat, however, can still play a positive role in expanding the car’s operating temperature range. The EQXX uses a heat pump to harness waste heat and any available ambient heat by dehumidifying moist ambient air. Put simply, heat is generated when the system changes water vapor in the air from gas to water. The repurposed hot air can then be used to keep the cabin warm – reducing the need for the car’s general power system to waste energy on generating heat (and thus, increasing range).
117 solar cells on the roof also help increase range by reducing energy drain on the 900-volt system. The solar cells can generate just over 15 miles (25 km) of range under ideal conditions in a single day. For the time being, the energy pulled from the sun is stored in a lightweight lithium-iron-phosphate battery for powering infotainment, lights, and other cabin functions; but Mercedes says they’re working on using solar power to charge the 900-volt system as well.
It’s no secret the Vision EQXX doesn’t look like a traditional sedan. The front half of the car may pass for something similar on the road today, but it’s in the rear where things get a bit “freaky.” Subjective views on the car’s appearance aside, it’s a difficult task to design a car with aerodynamics as the primary focus and still have it look decent. That being said, it’s pretty remarkable that Mercedes-Benz was able to achieve a drag coefficient of 0.17 while keeping smooth unoffensive body lines throughout.
For comparison, the Tesla Model S Plaid and Lucid Air have a Cd of 0.208 and 0.20, respectively (though this may be an apples-to-oranges comparison considering how much larger those cars are than the EQXX). Mercedes-Benz says a typical EV uses two-thirds of its battery capacity overcoming air resistance on longer trips – another opportunity to improve range!
To achieve this low Cd, the Vision EQXX uses a combination of active and passive aero; which the development of was greatly aided by the use of advanced digital modeling techniques. Mercedes-Benz highlights the improvements to car development using these digital collaboration tools – the result of which is a slippery design that was finalized in less than half the usual timeframe with fewer models made and less time spent in the wind tunnel.
The Vision EQXX has an extraordinarily small frontal area (even smaller than those on Daimler AG’s Smart car) that greatly helps the car slice through the air. A front air curtain combined with flush wheel covers, which sit atop lightweight magnesium wheels, keep air flowing smooth around the wheel arches. The wheels are also wrapped in special Bridgestone Turanza Eco tires to reduce weight and rolling resistance.
The Vision EQXX also utilizes air channels to guide cooling air over the hood – utilizing the aforementioned air shutters when necessary. The roofline continues to slope down into an elongated tail, forming a teardrop-shaped side profile, that executes into a rear track that’s two inches less than at the front. A retractable rear diffuser deploys at higher speeds to stabilize air streams and keep the Vision EQXX planted to the road while maintaining the engineering ethos of reducing parasitic drag.
Minimalism dominates the design philosophy of the Vision EQXX’s interior. By keeping shapes simple and omitting traditional trim elements, Mercedes-Benz was able to keep the interior lightweight and elegant. They also opted to use sustainable materials from organic sources, such as mushrooms and vegan silk (pinkies up), while strictly adhering to the principle of not using any animal-derived products.
The door-pulls are made from AMsilk’s Biosteel fiber (vegan silk), seat cushions from MyloTM vegan leather (mycelium derived), carpets from bamboo fiber… and you get the point. The interior of the Vision EQXX is essentially a high-tech salad of sustainable materials. Again, every bit plays a role in increasing range, efficiency, and ultimately the sustainability of producing cars. The Vision EQXX is a halo car after all; and future Mercedes-Benz models will draw from the technology and materials at display here.
Speaking of display, that large 47.5-inch screen dominates the cabin and utilizes game-engine-powered interfaces that “bring the real-world into the car.” Spanning from one A-pillar to the other, the 8K display houses a plethora of evolved traditional features such as real-time 3D navigation with a new road trip sidekick dubbed the “Hey Mercedes” voice assistant. Now equipped with its own “distinctive character and personality,” the virtual assistant makes conversation between the driver and car more natural and intuitive (according to Mercedes-Benz).
We’re not sure this is quite what people had in mind when they asked for EVs to have more character, but the presence of machine learning and artificial intelligence in future cars is inevitable given society’s technological trajectory. Without going into depth about what “neuromorphic computing” is and how it works, the systems Mercedes-Benz engineers developed using California BrainChip’s Akida hardware and software significantly reduce energy draw from AI technologies. Less power draw = more range.
Mimicking the way nature handles biological structures, the materials used throughout the Vision EQXX’s structure are present only in places where necessary. If there’s no load, there’s no material; and so weight is decreased and stiffness is increased.
The rear floor, dubbed BIONEQXX, takes these principles to heart and is developed using the largest aluminum casting at Mercedes-Benz, called BIONICAST. The process creates a single part, rather than conventional processes that join multiple parts together, resulting in a structure that’s significantly lighter, more rigid, and performs better in crash testing. The aforementioned vertical process of advanced digital systems, which utilize 3D modeling tools and graphics used in game development and Hollywood animations, enabled creating this new casting method in half the time. The BIONICAST process of structural casting that resembles organic shapes is used in various other places as well, such as the windshield wiper and motor and front suspension damper domes.
The Vision EQXX uses MS1500 high strength martensitic steel during the body-in-white stage of manufacturing (when the frame is being put together). This allows for weight that rivals aluminum while maintaining high safety in the case of an accident. The doors are made from aluminum-reinforced hybrid carbon and glass reinforced plastics (CFRP and GFRP – materials familiar to those who have modified their cars with aftermarket body pieces). Paired with a new polyamide foam, the impact absorption of a side collision is improved while improving weight, stiffness, and ductility.
Unsprung weight was also reduced by use of aluminum alloy for the brake disks (this works because the EV utilizes its motors for regenerative braking as well). On top of aluminum being corrosion resistant, brake dust emissions was reduced by 90% due to a new coating. The springs are also made of a new advanced glass-fiber-reinforced plastic, reducing weight further compared to standard coil springs.
All in all, the Vision EQXX weighs in at about 3,858 lb. – beefy by compact ICE sedan standards, but a featherweight when compared to the Lucid Air (~5,200 lb) and Tesla Model S Long Range (~4,560 lb). Again, given the size difference of these three, this comparison may be apples-to-oranges; but Lucid and Tesla are the current range leaders in the space.
Different approaches, different outcomes
Although Tesla has already picked up the pace on producing hundreds of thousands of conventional looking EVs, other automakers playing catch-up are showing just how diverse the outcomes can be when transitioning to electric technologies. Mercedes-Benz seems to have taken a more dramatic approach to efficiency by sacrificing the traditional sedan shape in the name of increased aerodynamics, reducing weight wherever possible, and introducing a slew of new materials and advanced processes to the mix. The result is essentially an EV hypermiler: prioritizing efficiency and sustainability over all.
Although the Vision EQXX’s design (and future Mercedes-Benz models that take influence from it) may take consumers time to adjust to, the undeniable advancements made to car development and material processes will surely be a benefit to the industry as a whole. With range-anxiety soon becoming a thing of the past, the directions taken to differentiate features and designs across different automakers will undoubtedly be exciting to watch.