Mercedes-Benz unveiled the VISION EQXX electric concept car (earlier post)—a highly efficient, sleek concept car capable of exceeding 1,000 kilometers (620 miles) on a single charge with an outstanding energy consumption of less than 10 kWh per 100 kilometers (efficiency of more than 6 miles per kWh).
The Mercedes-Benz VISION EQXX is how we imagine the future of electric cars. Just one-and-a-half years ago, we started this project leading to the most efficient Mercedes-Benz ever built—with an outstanding energy consumption of less than 10 kWh per 100 kilometers. It has a range of more than 1,000 kilometers (620 miles) on a single charge using a battery that would fit even into a compact vehicle. The VISION EQXX is an advanced car in so many dimensions—and it even looks stunning and futuristic. With that, it underlines where our entire company is headed: We will build the world’s most desirable electric cars.—Ola Källenius, Chairman of the Board of Management of Daimler AG and Mercedes-Benz AG
Rather than simply increasing the size of the battery, the cross-functional, international design and envineering team focused on maximizing long- distance efficiency. They pulled out all the stops in drivetrain efficiency, energy density, aerodynamics and lightweight design.
The technology program behind the VISION EQXX will define and enable future Mercedes-Benz models and features. As a halo car, the VISION EQXX firmly establishes Mercedes-Benz as the brand that pairs luxury with technology in the automotive world and beyond. And the way we developed it is as revolutionary as the vehicle itself. VISION EQXX has seen the best minds from our R&D centers work together with engineers from our Formula 1 and Formula E programs. They are proving that innovations from motorsport—where powertrains are already highly electrified—have immediate relevance for road car development. We are challenging current development processes with innovative spirit and outside-the-box thinking. This truly is the way forward.—Markus Schäfer, Member of the Board of Management of Daimler AG and Mercedes-Benz AG, Chief Technology Officer responsible for Development and Procurement
In addition to its energy efficiency, VISION EQXX offers solutions to pressing issues. For instance, sustainable materials throughout decreases the carbon footprint considerably. Its UI/UX features a new one-piece display that comes to life with responsive real-time graphics and spans the entire width of the vehicle. Other elements of the UI/UX help the car and driver work together as one, and even use technology that mimics the workings of the human brain. Further, the software-led development process that delivered it revolutionizes the way electric cars are designed, the company said.
This car is one outcome of an ongoing program that is delivering a blueprint for the future of automotive engineering. Many of its features and developments are already being integrated into production, including the next generation of the MMA – the Mercedes-Benz Modular Architecture for compact and medium-sized cars.
Some of the other highlights of the VISION EQXX include:
The battery pack in the VISION EQXX holds almost 100 kWh of energy, yet has 50% less volume and is 30% lighter than the already benchmark pack in EQS.
Exterior designers and aerodynamicists delivered a benchmark drag coefficient of Cd 0.175
A team of Mercedes-Benz engineers worked with the world's fastest race lab at High Performance Powertrains (HPP) and Mercedes-Benz Grand Prix (MGP) to engineer a highly efficient and compact electric drivetrain and lightweight battery case.
Inspired by natural forms and in partnership with innovative start-ups, engineers used advanced digital tools to lower weight and reduce waste by removing excess material assisted by 3D printing.
Ultra-low-rolling-resistance tires with optimized aerodynamic geometry combine with lightweight magnesium wheels for increased range.
Lightweight brake discs made from aluminum alloy help keep weight down.
Ultra-thin solar panels on the roof feed the battery system for up to 25 km of extra range.
VISION EQXX: key technical data
|Battery energy content, usable||kWh||<100|
|Max. system voltage||Volts||>900|
|Energy consumption||kWh/100 km
|Max. power output||kW||~150|
|Gross vehicle weight||lbs||~3,858|
Battery pack. The electric drive unit in the VISION EQXX is a dedicated unit consisting of the electric motor, transmission and power electronics featuring a new generation of silicon carbides. The power electronics unit is based on the upcoming Mercedes-AMG Project ONE hypercar.
Rather than simply increasing the size of the battery, Mercedes-Benz and the HPP team developed a completely new battery pack for the VISION EQXX, achieving an energy density of close to 400 Wh/l. This benchmark figure is what made it possible to fit a battery pack with just under 100 kWh of usable energy into the compact dimensions of the VISION EQXX.
The substantial increase in energy density comes in part from significant progress in the chemistry of the anodes. Their higher silicon content and advanced composition mean they can hold considerably more energy than commonly used anodes. Another feature that contributed to the impressive energy density is the high level of integration in the battery pack.
This platform, developed jointly by Mercedes-Benz R&D and HPP, created more room for cells and helped reduce the overall weight. The separate compartment for the electrical and electronic (EE) components, called the OneBox, likewise made more room for cells, with added benefits for installation and removal. The OneBox also incorporates novel safety devices with energy efficient operations that consume significantly less energy than the equivalent component in a production EV.
Tasked with pushing the envelope of technical feasibility on all levels, the battery development team also decided to experiment with an unusually high voltage. Increasing the voltage to more than 900 volts proved an extremely useful research tool for the development of the power electronics. The team was able to gather a great deal of valuable data and is currently assessing the potential benefits and implications for future series production.
Several more aspects of the battery design add to its exceptional efficiency. For example, its lightweight lid was engineered jointly by Mercedes-AMG HPP and their chassis partners at Mercedes-Grand Prix. The lid is made from a unique, sustainable composite material derived from sugar-cane waste, reinforced with carbon fiber, as used in Formula 1. The battery also features active cell balancing, which means drawing the energy evenly from the cells while the car is driving—in effect, giving it greater stamina. Overall, the battery weighs around 1,091 lbs, including the OneBox.
Thermal management system. Those who paid attention in physics class will know that heat is an energy form in a new guise. The VISION EQXX has an advanced thermal-management system that preserves the thermal energy and, significantly reduces cooling drag. Both contribute to maximum efficiency.
The Mercedes-Benz “cooling-on-demand” concept has been further developed for the VISION EQXX not only for optimal cooling based on the prevailing circumstances. The exceptional efficiency of the electric drive unit means it generates only minimal waste heat. This helped keep the thermal management system extremely small and lightweight.
The carefully engineered interaction of aero-shutters, coolant valves and water pumps ensures the electric drive unit, comprising the power electronics, electric motor and transmission, maintains the most efficient temperature balance at minimum energy cost. Technically, this system is a combination of an innovative air-flow management system and a cooling plate.
The cooling plate is installed in the vehicle floor, enabling it to take advantage of the air flowing along the underside of the VISION EQXX. This is the most aerodynamically efficient way of keeping the electric drive unit cool under normal conditions, allowing the vehicle to gain about 20 kilometers (12 miles) of range in the most aerodynamic mode.
Only when the weather is hot or the driving style is “lively” does the cooling system ramp up a notch. Shutters that are normally closed at the front of the VISION EQXX open when things heat up, and send extra cooling air along a system of air guides. The inlets for these air guides are cleverly located along the front bumper's highest-pressure zone. Conversely, the outlets are in low-pressure zones along the top of the hood.
The advantage of this cooling-on-demand approach is that when the shutters are open, it adds only seven points (0.007) to the drag coefficient. If cooling is required when the vehicle is at a standstill, a backup cooling fan kicks in (thermal-efficiency mode).
Heat pump. The multi-source heat pump recovers waste heat from the drivetrain, and has an external heat exchanger that draws heat from the ambient air. Not available in previous Mercedes-Benz heat pumps, this feature increases the operating temperature range. This is especially handy for heating up the cabin quickly and is highly effective at lower temperatures.
To squeeze out every last bit of heat, it uses the evaporator enthalpy when dehumidifying moist ambient air. Enthalpy is the latent energy released as heat when water vapor in the air changes state from gas to water.
Solar power. The electric system that powers many of the ancillaries in the VISION EQXX draws additional energy from 117 solar cells on the roof. The system was developed in collaboration with the Fraunhofer Institute for Solar Energy Systems ISE. The net result of reducing the energy drain on the high-voltage system is an increase in range. On a single day and under ideal conditions, this can add up to 25 km (15 miles) of range on long-distance journeys.
The solar energy is stored in a lightweight lithium-iron-phosphate battery, which supplies a climate blower, the lights, the infotainment system and other ancillaries. Mercedes-Benz and its partners are working towards using solar power to charge the high-voltage system, too.
BIONEQXX casting. Currently the largest aluminum structural casting at Mercedes-Benz, BIONEQXX is the major structural component at the rear end of the VISION EQXX—the rear floor. It was developed in-house by Mercedes-Benz using entirely digital techniques and a software approach that is unique within the automotive sector. The result is optimum functionality packaged within the compact dimensions of the available space. The team created this manufacturable one-part casting in just four months.
Taking their cues from organic forms, the development engineers sought to use material only where necessary for structural function, i.e. where loads are exerted. In line with the laws of nature, where there is no load there is no need for material.
The most important of the structural criteria is the need for very high rigidity and excellent crash performance. The beauty of the one-part BIONEQXX casting is the ability to pair this with functional integration within an extremely lightweight single component rather than an assembly of multiple parts joined together.
In addition to classic optimization techniques, the team also applied a unique collaboration model that included graphics and polygonal modeling tools used in the 3D gaming industry and Hollywood animations.
Used by Mercedes-Benz engineers in the automotive context, these tools help identify stresses and load paths in a component. All of this happens digitally, before anything is cast in metal, speeding up the development process considerably, and enabling a bionic shell structure to be created in half the time.
The resulting one-part casting has a web-like appearance with gaps where there is no need for structural elements. However, the rear floor of a vehicle is subject to more than just physical loads in everyday use. It has to withstand attempts by nature to get inside the car in the form of water and dirt. To address this, Mercedes-Benz engineers turned once more to external partner UBQ Materials.
The sustainable plastic substitute developed by the Israel-based start-up is made from the kind of waste that typically ends up in landfill. This includes food and garden waste as well as mixed plastics, cardboard and even baby diapers. Two pounds of UBQ removes 3 lbs of trash from landfill, of which around 0.6 lbs is water.
The openings in the BIONEQXX rear-floor casting were closed using patches made from UBQ produced on a 3D printer. A total of 42 UBQ patches were designed using shape optimization to achieve extremely high stiffness and sound-dampening qualities. Once inserted into the BIONEQXX casting using a special bonding process, the final unit is fully sealed against the effects of water and dirt. The resulting part indicates that this innovative engineering approach has the potential to achieve weight savings of between 15 and 20% compared to a conventionally produced component. It marks a milestone in lightweight design that meets the exacting Mercedes-Benz quality requirements.
BIONICAST damper dome. BIONICAST is a Mercedes-Benz registered trademark applied to structural castings engineered according to the principles of nature. In addition to the BIONEQXX rear-floor casting, another BIONICAST component that features in the VISION EQXX is the damper domes which accommodate the suspension components at the front of the car.
Like the BIONEQXX casting, they too contribute significantly to keeping weight to a minimum, saving around 9 lbs compared with conventional pressed domes.
The bracket carrying the windshield wipers and motor on the VISION EQXX was likewise designed using principles of bionic engineering. Here, too, the pioneering technique proved invaluable in keeping weight to a minimum while maximizing functionality within the tight packaging constraints.
This technology has already been transferred to Mercedes-Benz production models. For example, the chassis components in the new EQS have been modified to reduce weight by increasing stiffness.
Advanced bodyshell materials. The VISION EQXX features a raft of advanced materials that deliver practical functionality and safety to Mercedes-Benz standards. Several of these materials are currently being used in the development of future production models.
The MS1500 ultra-high strength martensitic steel used in the VISION EQXX marks a first for a Mercedes-Benz body-in-white application. The exceptional strength of this material offers excellent occupant protection in the event of a crash, while keeping weight to a minimum.
The body-in-white of the VISION EQXX is one of the first Mercedes-Benz applications of low-CO2 flat steel produced with 100% scrap using an electric-arc furnace technique. These low-CO2 steel grades have been introduced recently in Mercedes-Benz production vehicles and represent a blueprint for future models.
The doors of the VISION EQXX are made from a hybrid of CFRP and GFRP (carbon- and glass-fiber reinforced plastics) components with aluminum reinforcements. As well as the weight benefits, this design also achieves a careful balance of stiffness and ductility in the event of a crash. Meanwhile, a new polyamide foam reinforces the lower edge of the door and optimizes energy absorption in a side-on collision.
On the chassis, aluminum brake discs reduce the mass significantly compared with cast steel discs. As well as being completely corrosion-free, this brake system designed by Mercedes-Benz Advanced Engineering also reduces brake dust emissions by up to 90% thanks to an innovative coating. Meanwhile, new advanced glass-fiber-reinforced plastic springs developed in partnership with Rheinmetall Automotive remove further weight compared with conventional coil springs.