How many kilometres can an all-electric CLA cover in 24 hours, including charging stops and driver changes? That was the question faced by the development team working to optimise the efficiency of the new all-electric compact class models. The impressive answer was provided by “Project N”, the internal code name for a project that is as secret as it is ambitious. N for Nardò: two close-to-production prototypes of the CLA set off on this high-speed route in southern Italy at the beginning of April 2024.
A CLA covered exactly 3,717 kilometres within 24 hours – and got further than other near-production electric vehicles The distance of the endurance run is equivalent to a trip from Trondheim (Norway) to Istanbul (Turkey). Air temperatures ranged from 13 °C at night to 29 °C during the day. The tarmac was even hotter.
The vehicle's battery was charged exactly 40 times at a standard charging station during the 24-hour test. The charging breaks only lasted around 10 minutes each time. If these are taken into account, the average speed was a remarkable 154.9 km/h. In the run-up to the drive, the experts at Mercedes determined the ideal charging strategy to maximise the average speed. On a real long-distance journey, this optimisation takes place via navigation with Electric Intelligence.
A CLA covered exactly 3,717 kilometres within 24 hours – and got further than other near-production electric vehicles The distance of the endurance run is equivalent to a trip from Trondheim (Norway) to Istanbul (Turkey). Air temperatures ranged from 13 °C at night to 29 °C during the day. The tarmac was even hotter.
The vehicle's battery was charged exactly 40 times at a standard charging station during the 24-hour test. The charging breaks only lasted around 10 minutes each time. If these are taken into account, the average speed was a remarkable 154.9 km/h. In the run-up to the drive, the experts at Mercedes determined the ideal charging strategy to maximise the average speed. On a real long-distance journey, this optimisation takes place via navigation with Electric Intelligence.
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MotorTranscript
00:00The electric drive developed by Mercedes-Benz for the new CLA sets new standards in terms
00:11of efficiency. For the first time, Mercedes-Benz is using an 800-volt system and a two-speed
00:18gearbox in the entry-level class. Much of the underlying technology is based on learnings
00:25from the Vision EQXX. The technological highlights of the drivetrain include an 800-volt electric
00:33architecture, batteries with new cell chemistry and high energy density, and the advanced
00:38drive units including a two-speed transmission on the main rear axle motor and disconnect
00:44unit, DCU, on the front axle in the 4MATIC models. Other highlights include a silicon
00:49carbide inverter and the OneBox. The compact up to 200 kW rear electric drive unit is designed
00:59as a permanently excited synchronous machine on the rear axle. This has a significantly
01:05lower proportion, almost 0%, of heavy rare earths than previous motor generations. The
01:13high-performance power electronics feature a silicon carbide inverter for particularly
01:18efficient energy utilisation. The drive architecture includes a two-speed gearbox on the rear axle.
01:27First gear, with a short ratio of 11 to 1, offers excellent acceleration from a standstill,
01:33enables a high towing capacity and also offers efficiency in urban traffic. Second gear,
01:40ratio 5 to 1, on the other hand, is designed for high efficiency on long journeys or at
01:44high speeds. The 4MATIC models also have an 80 kW drive unit on the front axle. This
01:55is switched on at lightning speed only when power or traction is required. This is handled
02:01by the so-called disconnect unit, DCU, which Mercedes-Benz is now using for the first time
02:07in the entry-level class. The DCU decouples the electric motor from the front axle so
02:13that the electric motor and parts of the transmission are stationary. This reduces
02:17front axle losses by 90% and increases the range. When the load is low, only the rear
02:24axle is driven and the electric motor on the front axle is decoupled. If a higher load
02:29is required or there is a high recuperation requirement, the DCU is closed at lightning
02:34speed and the front axle is engaged. The entire engagement and disengagement process takes
02:40around 0.2 seconds and is not noticeable. Intelligent recuperation contributes to the
02:47high efficiency of the models on the MMA platform. Almost all braking operations in everyday
02:53life are carried out with the aid of recuperation and not mechanically via the wheel brakes.
02:59In principle, the MMA models can even brake electrically until the vehicle comes to a
03:04standstill and thus recover kinetic energy. The innovative battery system is based on
03:12a highly modular architecture and contains two different cell chemistries for the MMA
03:17platform. The top variant with silicon oxide anodes for a higher energy density has a usable
03:24energy content of 85 kWh. Here, the proportion of cobalt has been further reduced to around
03:324%. The entry-level version with cathodes made of lithium-ion phosphate is available
03:38a few months after the market launch of the CLA. It has a usable energy content of up
03:44to 58 kWh and does not require rare raw materials such as cobalt and nickel. The 800-volt configuration
03:54allows high-power DC charging with up to 320 kW in the top version. Within 10 minutes,
04:0136 kWh of energy can be recharged. The OneBox is the central energy supply unit, regardless
04:09of whether DC or AC charging is required. If navigation with electric intelligence is
04:15activated, the battery is preheated during the journey if necessary. This preconditioning
04:21allows it to reach the optimum temperature for fast DC charging at the charging point.
04:27Current traffic conditions, occupancy and also the capacity of charging stations are
04:31taken into account when planning the route. Further model variants are planned for the
04:39near future. As shown in the Concept CLA class, the all-electric CLA achieves a range of more
04:46than 750 km WLTP. With an energy consumption of only around 12 kWh per 100 km, this is
04:57the one-litre car of the electric age.