Ahead of the upcoming world premiere of the Mercedes-Benz EQS, the manufacturer has released a lot of technical details for its upcoming all-electric flagship model.
The EQS is based on the new EVA platform that will be used in several other models, including the EQE and SUV versions of the EQS and EQE.
“The new generation of electric vehicles in the luxury and executive segment is based on a custom-developed architecture, which is scalable in every aspect and can be used across model series. The wheelbase and track as well as all other system components, especially the batteries, are variable thanks to the modular design. The vehicle concept is thus optimised to meet every requirement of a future-oriented, battery-electric model family.”
The top of the line electric Mercedes is supposed to be at the forefront of technology and as far as we can tell after the brief look at the numbers, it really is. Let’s get into it.
Battery
As we already know, the maximum range of the EQS to be up to 770 km (479 miles) under the WLTP test cycle (preliminary number) – “No cable reaches this far.”
Mercedes-Benz will offer two battery options for the EQS with a usable capacity of 107.8 kWh (26% more than in the EQC) or 90 kWh (83% of the bigger one).
If the bigger version is good for 770 km (479 miles), then the smaller version should offer over 640 km (398 miles) of WLTP range (the exact number will depend on the powertrain version and options).
Mercedes-Benz is using NCM 811 lithium-ion cells (cathode active material consists of nickel, cobalt and manganese in a ratio of 8:1:1) in pouch cells or hard-case/prismatic type. There can be 10 or 12 modules (90 and 108 kWh versions). The overall architecture is 400-volt.
As we can see, the pack has a liquid thermal management system with a bottom cooling plate (Coolant flows through the cavities of the aluminum extrusions of the battery frame) and a PTC auxiliary heater (Positive Temperature Coefficient) integrated into the cooling circuit.
The pack can be preheated or cooled before or while driving to reach the optimum temperature window at a fast-charging station.
The general over-the-air software update system includes the option to update the battery management system if needed.
The battery is expected to be quite durable as Mercedes-Benz expects to offer a warranty of up to 10 years or up ot 250,000 km (155,000 miles):
Performance promise through battery certificate for customers:
- Covers loss of capacity of the battery
- Valid for a term of ten years
- Or up 250,000 kilometres
Powertrain
Mercedes-Benz will offer multiple powertrain options. The base will be the rear-wheel-drive (RWD) version, with an option for dual-motor all-wheel-drive (AWD), the 4MATIC.
- EQS 450+: RWD versions: 245 kW
- EQS 580 4MATIC: AWD version: 385 kW (255 kW rear and 135 kW front)
- performance version: “even more powerful”
Despite the high power output, the top speed will be limited to 210 km/h (131 mph). The acceleration numbers were not released yet.
The NEDC energy consumption for two versions has been released:
- EQS 450+, NEDC: combined electrical consumption: 19.1-16.0 kWh/100 km
- EQS 580 4MATIC+, NEDC: combined electrical consumption: 20.0-16.9 kWh/100 km
The all-wheel driving 4MATIC versions will have Torque Shift function:
- Intelligently and continuously distributes the drive torques between the front and rear axles
- Ensures that the most efficient eATS (electric drivetrain) is used in each case
- Much faster response than with mechanical all-wheel drive
- eATS can be regulated independently of each other
- Torque is checked 10,000 times per minute and set if necessary
Mercedes-Benz is using permanently excited synchronous motors (rotor is fitted with permanent magnets), both in the front and rear. That’s not unusual, but the thing that has caught our attention is that the rear one has two three-phase stator windings.
It’s not a new concept but rarely used due to the higher cost of the motor and the requirement of six-phase power electronics. The advantage of having two windings is a much better characteristic of the electric machine. We guess that by intelligently control the current flow, you can achieve a similar effect on the torque characteristic like if there were a mechanical two-speed transmission, but there is none.
It should improve the performance (high starting torque at low speed and high torque at higher speeds), as well as the efficiency.
- Electric motors on the front and rear axles are modern permanently excited synchronous motors
- Motor particularly powerful on the rear axle due to six-phase operation: two windings with three phases each
- Stators with pull-in winding for a particularly strong magnetic field
- Very compact
Another thing that is worth mentioning is a very sophisticated state-of-the-art cooling system of the electric motors:
- Sophisticated thermal concept for high load capacity and multiple accelerations with consistently high performance
- What is known as a water lance in the shaft of the rotor cools the rotor
- Further cooling elements in the cooling circuit:
- Stator ribs
- Needle-shaped pin-fin structure on the inverter
- Transmission oil cooler: also more efficient during cold driving (gear oil is warmed up)
Mercedes-Benz said also that the EQS meets the highest demands for noise and vibration comfort, thanks to:
- NVH-optimised arrangement of the magnets inside the rotors (known as sheet metal cut)
- Reduces the use of rare earths at the same time
- Special winding (known as stator tilt)
- eATS have a special foam mat all around as an NVH cover
- Cover of the inverter is a sandwich construction made of three metal and plastic layers
- eATS are double decoupled via elastomeric bearings
- Front axle: with supporting frame
- Rear axle: with carrier
- Use of acoustic foams in body-in-white construction
- Main floor under the battery
- Designed with beading for NVH reasons
- New insulation part (welded-in foam) prevents excitations
- Two acoustic dividers in the tailgate reduce booming noise
The regenerative braking will be adjustable, with a few modes, and shift paddles on the steering wheel. The peak power is up to 290 kW in AWD versions.
- Adjustable by the driver in three steps via shift paddles on the steering wheel
- Situation-optimised with the help of the ECO Assistant
- In DAuto, up to 5 m/s² are achieved, of which 3 m/s² are due to energy recovery (2 m/s² via the wheel brakes)
- The recuperation output is up to 290 kW4
- Braking to stop is possible
- Deceleration is also for detected vehicles travelling ahead until they come to a stop, for example at traffic lights
- In versions with rear-wheel drive, recuperation is limited by traction
Charging
In terms of charging, Mercedes-Benz EQS will be equipped with a 22 kW (three-phase) on-board charger (at least in Europe) with an undisclosed option for more.
The DC fast charging will be up to 200 kW. We don’t know yet the charging curve, but there is a potential that it will be quite flat.
Mercedes-Benz promises that within 15 minutes the car will be able to replenish up to 300 km (186 miles) of WLTP range (the bigger battery version).
The EQS will be of course ready for the Plug & Charge for simple automatic charging and billing (at least at some networks like IONITY).
An interesting thing is that in Japan (the country of the CHAdeMO standard), the EQS will also allow bidirectional charging.
Navigation with Electric Intelligence
One of the most important features in the EQS will be the Navigation with Electric Intelligence, which combines the navigation with the database of charging infrastructure and battery management system to plan the route accounting charging stops and prepare the battery for charging at maximum power.
As far as Navigation with Electric Intelligence is concerned, the name says it all. Because it plans the fastest and most convenient route, including charging stops, based on numerous factors and reacts dynamically to traffic jams or a change in driving style, for example. In the EQS, navigation with Electric Intelligence is even more clever than before.
- Plans a fast and comfortable route in advance, including charging stops, based on numerous factors such as
- Calculated energy demand (topography, route, ambient temperature, speed, heating and cooling demand etc.)
- Ambient temperatures at the charging station
- Traffic situation on the planned route
- Number of charging stations available, their charging capacity and payment functions
- Responds dynamically to congestion and changes in energy demand
- Calculation in the cloud combined with on-board data
- In addition, the planned route can be edited individually
- The additional reserve at the destination and at the charging station (SoC, State of Charge) can be set, ten percent SoC is standard
- If “Charge at destination” is selected, this set reserve may be undershot at the destination
- New in the EQS
- Visualisation of whether the available battery capacity is sufficient to drive back to the starting point without charging
- Manually added charging stations along the route are given preference in route calculation
- Proposed charging stations can be excluded
- Calculation of the expected charging costs per charging stop
- Note from the “Active range monitoring” to activate ECO driving functions if there is a risk of not reaching the destination or the charging station with the selected settings
Aerodynamics
The final element that we would like to highlight is the aerodynamics with a cd value of 0.20 (a record for a production car). It’s one of the key factors to achieve a very long-range and minimize energy consumption.
Here is how Mercedes-Benz achieved the low drag coefficient and how minimized the noise:
- A world record. First production car with a cd value from 0.20
- Low spread of the individual models and wheels/tyres up to 22 inches
- The frontal area is 2.51 m2
- The purpose design brings numerous aerodynamic and aeroacoustic advantages
- Good coupé-like basic shape with flat windscreen
- Smooth underbody
- Lower cooling air requirement, louvre is mostly closed
- Attractively designed aero wheels are available in sizes 19, 20 and 21 inches
- A lot of aerodynamic fine tuning
- Wheel spoiler front and rear (arrow-shaped)
- Coordinated underbody panels
- Rear spoiler optimised for lift and air drag
- Extensive aerodynamics development
- By developing an entire Mercedes-EQ luxury model family, comparatively much capacity for basic development
- Several 1000 calculation runs in the virtual wind tunnel
- Approx. 700 CPUs per calculation
- Simulation helpful especially for outer skin and underbody concepts
- However, final optimisations still carried out physically in the wind tunnel with clay and hybrid models
- Due to the electrification of the powertrains, low wind noise becomes even more important
- Here, too, the EQS is among the top vehicles in its class
- Excellent aerodynamics is at the same time a good basis for low wind noise
- Extensive development steps to reduce wind noise
- Numerous optimisations in the area of door structure and door and side window seals with, for the first time, six side windows in a Mercedes
- Special acoustic comfort package with acoustically highly effective laminated glass panes
- A-pillar with specially shaped trim strip helps reduce wind noise as well as lower the cd value
- Retractable door handles
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Mercedes-Benz EQS spces:
- up to 770 km (479 miles) of WLTP range
- two battery versions:
107.8 kWh of usable battery capacity (12 modules, about 9 kWh each)
90 kWh of usable battery capacity (10 modules)
lithium-ion cells (pouch cells or hard-case/prismatic cells), NCM 811 chemistry
400-volt architecture - 0-100 km/h (62 mph): N/A
- top speed of 210 km/h (131 mph)
- powertrain options:
EQS 450+ rear-wheel drive (single motor): 245 kW and 568 Nm
EQS 580 4MATIC all-wheel drive (dual motor): 385 kW (255 kW rear and 135 kW front) and 855 Nm
performance version: “even more powerful”
both motors are permanently excited synchronous motors
peak regenerative brake up to 290 kW - AC charging (on-board): three-phase 22 kW (Europe); optional extra
- DC fast charging: up to 200 kW;
up to 300 km (186 miles) of WLTP range to be replenished in just 15 minutes
Plug & Charge feature - Cd value starting from 0.20
- EVA platform