Mercedes-Benz Vision EQXX concept traveled from Stuttgart Germany, across the Swiss Alps and Northern Italy, to its destination of Cassis on the Cote d'Azur in the south of France. This 1,008 km (626.3 Miles) @ 8.7 kWh per 100km (62.14 miles) of energy consumption.
The road trip started off by certification and sealing of the charge port and a team monitoring the auto the whole time.
This approach is what Mercedes-Benz calls Holistically Thinking, from the efficiency of the drive train to aerodynamics and down to the tiniest of detail, as a well working, great interfunctional collaboration and with external partners. This Holistical Thinking will be the new Blueprint for Mercedes automotive engineering as the benchmark for all Mercedes-Benz electrical vehicle efficiency and range for upcoming BEVs that go into production.
Mercedes says that road trips are a cultural touchstone and has been for decades being defined as the road trips the give us freedom, individuality, the very spirit of the automobile and the passing world, allowing one to stick a pin in the map saying I have visited these places.
Road trips drive the human spirit in our search for the great outdoors to the close intercity of driving.
The Journey to electric mobility is a road trip that will be exhilarating and challenging for humans the world over, yet for Mercedes-Benz the journey is clear with a clear goal of maximum efficiency through innovation. This will start with their battery efficiency.
The next step is a passive cooling of the drive train to reduce weight of the overall auto.
From the passive you then move to the on-demand active drivetrain cooling.
Heat Pumps are the future of BEVs, as Tesla has moved from AC units to new mini-Heat pump units, so has the legacy auto OEMs are moving to Heat pumps. This allows an actual superior heating and cooling affect by also controlling humidity which when unchecked causes what some people say is bone chilling cold on a winters day. Heat Pumps have been the optimal way to heat and cool a home and now we are starting to see them show up in the Auto.
The challenging route profile and varying weather conditions has showed how the VISION EQXX research prototype was able to handle the wide variety of challenging conditions via the onboard software. EQXX packed with innovations allowed the VISION EQXX to break through technological barriers across the board. This trip showed what was feasible for a one-day road trip that covered 4 countries.
This road trip had to deal with high speed motorways, mountain passes, various weather conditions and roadwork that offered various challenging driving situations.
This road trip started in cold conditions at Stuttgart R&D Center at 3 degrees Celsius (37.4 F) and ended at 18 Degrees Celsius (64.4 F) in Cassis near Marseille in the South of France.
A very common question is with electrical vehicles, how do I know what my range or as they say with an ICE MPG is?
To compare efficiencies of MPG to MPGe, Kilowatt-hours per 100 kilometers are a measure of electric vehicle energy efficiency equal to the Kilowatt-hours of energy needed for a vehicle to travel 100 kilometers.
The Kilowatt-hour per 100 kilometers is an SI unit of electric car efficiency in the metric system. Kilowatt-hour per 100 kilometers can be abbreviated as kWh/100km; for example 1 kilowatt-hour per 100 kilometers can be written as 1 kWh/100km.
The following chart should help make this conversion easy for those not used to metric scale.
Based on this chart for conversion of the EQXX range reported, we see that the Mercedes-Benz EQXX has about a 259 MPGe rating. This is extremely good for a 900V powered electrical car, clearly beating the best numbers that have been reported by Tesla to date.
The EQXX important facts as a glance:
- #MissionAccomplished: more than 1,000 km with a single battery charge in real everyday traffic allows for relaxed long-distance journeys.
- #EnergyWizard: efficiency-enhancing measures lead to an outstandingly low consumption of 8.7 kWh per 100 km.
- #AeroChamp: outstanding work in aerodynamics and exterior design enables a benchmark drag coefficient of 0.17, which has a particularly positive effect on fuel consumption at high speeds on the motorway.
- #RollingEfficiency: tyres with a significantly lower rolling resistance than the class A required by the EU tyre label and improved aerodynamic geometry, combined with lightweight magnesium wheels, provide more range.
- #ElectricDrive: the radically new drive concept developed by Mercedes-Benz achieves a benchmark efficiency of 95% from battery to wheels.
- #PassiveCooling: innovative passive drivetrain cooling via a cooling plate in the underbody.
- #BionicEngineering: advanced digital tools enable innovative lightweight designs that increase efficiency and range.
- #SolarPower: ultra-thin roof panels feed the battery system and provide up to 25 km of additional range.
- #SoftwareDriven: software-driven approach is the key to success in achieving efficiency targets and a fast development process, including a sophisticated battery management system.
- #GlobalResponsibleLeadership: with the VISION EQXX, Mercedes-Benz is stepping up the pace to “Lead in Electric” and “Lead in Car Software” and to set standards for sustainable mobility.
Technical Data at a Glance:
The team kept a trip log of the progress and thoughts and as such, Mercedes released the following excerpts from the trip log.
An excerpt from the trip log:
Up to 140 km/h on the motorway – low drag and rolling resistance pay off
The first leg from Sindelfingen to the north-eastern border of Switzerland runs along Autobahn 81. At times, the VISION EQXX sliced through the wind at speeds of up to 140 km/h. With its low cd value of 0.17, it gives the wind virtually nothing to grab hold of. This world-beating figure for a road-legal vehicle results from the intelligent interaction of many individual measures. It starts with the basic shape of the body, cradling the smooth-surfaced dome of the greenhouse as it flows elegantly like a water droplet towards the rear. Equally beneficial to the aerodynamics are the small frontal area of 2.12 m² and the reduced rear track. Because this is 50 mm narrower than at the front, the rear wheels roll in the slipstream of the front wheels. The active rear diffuser, which automatically deploys at 60 km/h, provides better airflow and thus contributes significantly to the reduced drag.
The technology vehicle gains further efficiency benefits from its tyres, with their extremely low rolling-resistance rating of 4.7. Bridgestone developed these specifically for the VISION EQXX in partnership with Mercedes-Benz. By way of comparison, the current EU tyre label requires a figure of 6.5 for the top rating in Class A. The EQS uses tyres with a rolling resistance of 5.9, which is significantly lower. With the VISION EQXX, Mercedes-Benz is now going one step further. A striking feature is the size of the new tyres. The dimensions 185/65 R 20 97 T mean they have a large diameter and a narrow tread. The specialist Turanza Eco tyres combine two innovative Bridgestone technologies that enable a higher range: ENLITEN technology reduces both rolling resistance and weight by up to 20 percent. The ologic technology reduces tyre deformation while driving, in part through a more tensioned belt section. In addition, the transition from the tyre to the wheel rim was optimised in cooperation with the Mercedes-Benz aerodynamics team.
Over the mountains – the lightweight dividend
The VISION EQXX's special features also include its carefully thought-through lightweight construction, which has a particularly positive effect on uphill climbs. Any keen cyclist knows why it’s always the same kind of rider out in front on mountain stages. The heavier, more muscular sprinters are always staring at the taillights of the wiry featherweights on the uphill slogs. The decisive factor is the power-to-weight ratio. It’s not about sheer performance in the sense of “faster; higher; further” but about endurance and lower energy consumption.
This is exactly what the VISION EQXX demonstrates impressively on the approach to the Gotthard Tunnel heading for Italy. On the section between Amsteg and Göschenen, there’s a 14-kilometre uphill stretch with a gradient of up to five percent. It is here, where every gram of extra weight eats up energy, that the VISION EQXX scores sustainable points with its unladen weight of only 1,755 kilograms.
The lightweight design concept of the VISION EQXX is comprehensive – from the materials used to innovative bionic structures that deliver a favourable power-to-weight ratio. Examples of this are the sustainable carbon-fibre-sugar composite material used for the upper part of the battery, which is also used in Formula 1, and the BIONEQXXTM rear floor, manufactured using an aluminium casting process. The light metal structural component replaces a much heavier assembly of several interconnected parts. It has gaps in places where structural strength is not required, thus saving material. This innovative design approach results in a weight saving of up to 20 percent compared to a conventionally manufactured component.
A large part of the weight efficiency is also due to the dedicated electric chassis with lightweight F1 subframe and aluminium brake discs. Another is the battery. At 100 kWh, the power storage unit developed specifically for the VISION EQXX has almost the same amount of energy as the battery of the EQS, which is already a global benchmark among electric cars currently on the market. However, it has 50 percent less volume and is 30 percent lighter. The outcome is that the compact battery, measuring just 200 x 126 x 11 cm, is also comparatively light at 495 kilograms and fits in a compact car. The electric drive was developed in cooperation with the experts from Mercedes-AMG Petronas F1 Team.
Back down the hill – recuperation is the name of the game
After the Gotthard Tunnel, the road goes downhill for a very long way. This is where the VISION EQXX makes the most of the situation in its own way. While the golden rule of the professional cyclist is to go full throttle downhill to make up time, the VISION EQXX does the unthinkable and regenerates its energy reserves. In electric cars, this is called recuperation, the recovery of braking energy. In this discipline, too, the VISION EQXX sets new standards thanks to its highly efficient electric powertrain.
The VISION EQXX can use the recuperation effect on any type of gradient and during every braking manoeuvre, thus extending its range. A positive side effect of this electric braking is that the mechanical brakes are barely used. This makes it possible for the first time to use new types of aluminium brake discs that weigh significantly less than their steel counterparts.
Solar roof – energy snack in sunny Italy
The VISION EQXX gets a hearty energy snack around midday in the Po Valley near Milan – not at the charging station, but via its fixed solar roof. The 117 solar cells feed the 12-volt battery, which supplies power to auxiliary consumers such as the navigation system. The added value is measurable through the load this removes from the high-voltage battery, displayed by the onboard computer. Overall, the solar booster increases the range by more than two percent – which adds up to a good 25 kilometres on a journey of over 1,000 kilometres.
Innovative eATS – powerful, frugal, enduring
The electric drive unit in the VISION EQXX – consisting of the electric motor, transmission and power electronics – was developed together with the F1 specialists at HPP, and has a peak output of 180 kW. Thanks to the torque available from the first rev of the motor and the very low aerodynamic and rolling resistance of the VISION EQXX, its full potential is barely tapped during the entire trip. Much more important than top performance are other factors. Just like the battery, the electric drive unit is compact, lightweight and highly efficient. Its average efficiency in this application is 95%. That means 95% of the energy from the battery ends up at the wheels.
This goes hand-in-hand with further efficiency benefits such as the reduction of losses in the drivetrain. The engineers at Mercedes-Benz have succeeded in reducing the total losses in the drivetrain (motor, inverter and transmission) by 44% compared to an e-drive that is not based on this project. This makes a big different to the bottom line, with one percent more efficiency bringing two percent more range. This effect is further amplified by the battery of the VISION EQXX, thanks to its remarkable energy density of almost 400 Wh/l and particularly high operating voltage of more than 900 volts. And on the topic of high voltage: The VISION EQXX marks the first use of this technology, which proves itself throughout the entire journey. With not a single problem such as line overheating, everything is well under control. There are further efficiency from the active cell balancing. It ensures that energy is drawn evenly from the cells during the journey, which increases the usable energy and thus the range even more.
Efficient thermal management system – passive powertrain cooling is all it takes
Since the electric drivetrain generates little waste heat thanks to its high efficiency, passive cooling is sufficient throughout the journey. The cooling plate in the underbody uses the airflow to ensure even cooling. This aerodynamically highly efficient solution increases the range by 20 kilometres, while the cd value remains unchanged at a low 0.17.
Even on the ascent to the Gotthard Tunnel, the air shutters remain closed. The air control system would only open an additional airpath if there was an increased demand for cooling the electric drive or for climate control inside the cabin on hot days or if the heat pump was running on cold days. The airpath then connects the high-pressure zone at the front of the vehicle with the low-pressure zones along the top of the bonnet. This enables highly efficient thermal management with minimal air resistance. With the shutters open, the cd value would increase by only seven points (0.007).
Efficiency assistant – actively helping to save energy
Whether e-drive or combustion engine, the amount of energy a motor consumes in practice ultimately depends a great deal on driving style. In Switzerland, Italy and France, “pedal to the metal” is not an option anyway, thanks to speed limits and attentive law-enforcement officers. However, the VISION EQXX also proves to be an intelligent sidekick, assisting the driver like a co-pilot with tips on the best possible driving style. The efficiency assistant provides information on energy flow, battery status, topography and even the direction and intensity of wind and sun.
The UI/UX features an all-new, one-piece display that spans the entire width of the interior. Elements of the user interface support seamless interaction between the driver and the vehicle. These include Artificial Intelligence (AI) that mimics the way the human brain works. In the VISION EQXX, Mercedes-Benz takes a radically new UI/UX approach. A game engine takes UI graphics to a whole new level. The UI shows how real-time graphics open up new digital possibilities by reacting instantly to the driver’s needs and bringing the real world into the vehicle.
Finale in France – crossing the finish line with around 140 kilometres of remaining range
Shortly before crossing the finish line in Cassis, the VISION EQXX gathered energy once more through recuperation. After 11 hours and 32 minutes of driving time, it ended its 1,008-kilometre road trip with a remaining range of around 140 kilometres. This means it could have set off again for a jaunt along the Mediterranean coastline without recharging.
The VISION EQXX has unequivocally proven the real-world potential of outstanding efficiency for electric vehicles. This first road trip to Cassis is a watershed moment on a much bigger journey that is far from over. There’s a lot more to come.
The big question that needs to be asked is HOW MUCH OF THIS TECHNOLOGY will actually make it into the Mercedes-Benz EQ series of electrical vehicles?
The VISION EQXX battery slide provided by Mercedes-Benz alone shows the big differences between the current EQS and the EQXX.
- Anode - EQS is Graphite, EQXX is High-silicon
- Cooling - EQS Liquid-cooled, EQXX Air-cooled
- Battery Construction - EQS Modular, EQXX cell2pack
- Voltage - EQS 450 V, EQXX 900V
- Energy Content - EQS 107.8 kWh, EQXX 100 kWh
One interesting observation is that the EQXX is RWD powered by a 180-kW (241 HP) motor versus the EQS is powered by RWD 245 kW (329 HP) or AWD 385 kW (516 HP) motors. There are also special modes that push the EQS in RWD to 500 plus HP and the AWD to 700 HP. The power consumed to go fast also affects long-term driving range of the battery packs.
The EQXX has this long thin rear fin that clearly helps with down force and yet I would doubt it would make it into production as walking humans would clearly hit it not noticing it.
It is an interesting conceptual study from the very narrow tires to the overall air stream designed for maximum mileage range. Clearly some things will make it into production for cars and SUVs but not everything.
What do you think of this concept drive and how real can it be in a production electric auto?
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