Powering up innovation
Mercedes-Benz will be providing two innovative powertrains in its upcoming vehicle architecture.
The company is incorporating the findings from its Vision EQXX technology platform into series production vehicles.
Leading the way is the new all-electric CLA. It’s the first model based on the Mercedes-Benz Modular Architecture (MMA).
The centrepiece of this flexible architecture is the so-called skateboard chassis, a floor assembly designed primarily for EVs, including the corresponding drive and chassis components.
The body design varies, however. In the newly defined entry-level segment, Mercedes-Benz is planning four models. In addition to the CLA as a four-door sedan these include a shooting brake and two SUVs.
The company will also rely on intelligent modularity with a scalable skateboard design for future model families in other segments.
Because Mercedes-Benz is striving for a leading role in electric driving and software, it has massively increased its development activities.
This includes the recent opening of its eCampus in Stuttgart-Untertürkheim to develop cells and batteries for future EVs.
The aim is to develop chemical combinations and optimised production processes for high-performance cells to reduce battery costs by more than 30 per cent in coming years.
Parts of the development and testing of the new MMA models have taken place at an electric software hub (ESH) in Sindelfingen.
Mercedes-Benz’s new powertrain’s new electric drive unit (EDU 2.0) is the first of a new generation of units. They form an intelligent modular system.
With the main drive on the rear axle for optimum traction and driving characteristics, the marque is now introducing a drive layout familiar from mid-size and luxury classes to the entry-level segment.
The 200kW EDU 2.0 has a permanently excited synchronous machine (PSM) on the rear axle was developed entirely in-house.
The high-performance power electronics are equipped with a silicon carbide (SiC) inverter for efficient energy use. The transmission control and inverter are integrated in a single component.
The EDU 2.0 reconciles the conflicting goals of maximum torque, top speed and efficiency, especially in real driving conditions. This is because the high torque ensures dynamic performance. It’s also helpful when negotiating mountain passes or towing trailers.
Another strength is the compactness of the EDU 2.0, which benefits the interior dimensions and volume of the rear boot.
The 4MATIC models have an 80kW drive unit on the front axle. For efficiency, this is also equipped with a next-generation inverter with a SiC and designed as a PSM.
The front electric motor acts as a “boost” drive. Depending on the situation or programme, it’s only switched on when corresponding power or traction is required.
This task is performed by the disconnect unit (DCU), which Mercedes-Benz is using for the first time in the entry-level segment.
For greater efficiency, the DCU can decouple the electric motor on the front axle at lightning speed when the load is low, so the electric motor and parts of the transmission are at a standstill. This reduces front axle losses by 90 per cent and increases range.
In the case of the Concept CLA Class, this would correspond to a range of more than 750km on the WLTP.
With an energy consumption of just 12kWh/100km, the Concept CLA Class would be the “one-litre car” of the electric age.
Mercedes-Benz is using 800-volt electrical architecture for the first time. This maximises efficiency and performance and, in conjunction with the new battery generation, can significantly reduce charging time.
Within 10 minutes, a range of up to 300km can be added to the Concept CLA Class using DC fast charging.
The CLA has already done better than other close-to-production EV in a record attempt. In a test drive, a pre-series model covered 3,717km in 24 hours. The two-speed transmission on the rear axle’s main drive not only contributes to efficiency, but also enables dynamic driving performance.
Customers will be able to choose between batteries with two different cell chemistries. The cells of the premium version with a usable energy content totalling 85kWh have anodes in which silicon oxide is added to the graphite.
Compared to the predecessor battery with conventional graphite anodes, the gravimetric energy density is up to 20 per cent higher.
The use of raw materials has been further optimised and reduced. In particular, the proportion of cobalt has been further reduced.
This is followed by an all-electric entry-level variant with a lithium-iron phosphate cathode battery. Its usable energy content is 58kWh.
Mercedes-Benz is emphasising its claim to leadership in drive systems – whether electric or hybrid.
Efficiency is also the key to the development of modern hybrid systems. MMA architecture vehicles will also be available as a hybrid with 48-volt technology.
The electric motor with 20kW drive power has been integrated into a new electrified eight-speed dual-clutch transmission together with an inverter. The electrical energy of up to 1.3kWh is provided by a new 48-volt battery with lithium-ion technology and a flat-pack design.
Thanks to energy recuperation and all-electric driving capability at urban speeds, this drivetrain is “particularly” efficient. This is enhanced by electric coasting up to around 100kph.
The combustion engine is a new four-cylinder petrol engine. The hybrid drivetrain is initially available in three power levels with 100, 120 or 140kW.
