On the path to purely electric mobility, plug-in hybrids undoubtedly represent the key transition technology. With its EQ Power models, Mercedes-Benz has an efficient transmission which is already in its third generation, marking a new step towards CO2-neutral mobility. At the end of 2020, Mercedes-Benz customers will be able to discover the benefits of this technology in more than 20 different models.
The advantages of electric propulsion and the combustion engine complement each other in the plug-in hybrid by compensating for the restrictions of the respective systems. The main advantage of hybrid technology is the ability to drive zero emission locally when it counts, in combination with the range of a conventional personal car. Drivers of plug-in hybrids should not face any autonomy anxiety.
Relatively large lithium-ion batteries guarantee purely electric operating ranges that are more than sufficient for most daily journeys. Mercedes-Benz will deploy this pioneering technology across its entire range – from Class A to Class S, from GLA to GLE, with combustion engines fitted with electric supports. They get their energy from batteries which can be recharged easily and quickly at home, on a charging station at work or on the public network.
Mercedes-Benz Research has used methods such as an app, EQ Ready, to determine how far distances are covered on average by electric vehicle drivers. Analysis shows that a purely electric range of 50 kilometers is sufficient for 90% of all journeys. The proportion of longer journeys is extremely low – more than 90% of all journeys are less than 100 km and most of them are less than 400 km. Third generation plug-in hybrids are ideal for these results.
Rechargeable hybrid technology for compact models
For models with a transverse engine and the 8G-DCT dual-clutch transmission, a compact hybrid torso has been developed. Its stator is integrated in the torso housing, the rotor of the electric motor includes the low-loss clutch module operating in an oil bath. On-demand stator and rotor cooling makes it possible to call on the maximum and continuous performance of the electrical system without any compromise. The structure of the hybrid components allows Mercedes-Benz to do without a conventional 12 V starter, since only the electrical system is used to start and boost the combustion engine. In addition to its efficiency, the compact drive unit provides a generous amount of driving pleasure and fitness for daily use. The technical strengths of compact hybrids speak for themselves:
- Electric range up to 77 km (NEDC)
- 75 kW electrical power
- Combined power of 160 kW (218 hp)
- Combined torque of 450 Nm
- Maximum speed of 140 km / h (electric) / 235 km / h (total; Class A compact sedan)
- Acceleration 0-100 km / h in 6.6 seconds (Class A compact sedan)
- Almost no restrictions in terms of cargo space
As the EQ Power combines the electrical system and the 1.33 liter four-cylinder engine, it generates 160 kW (218 hp) and delivers an overall maximum torque of 450 Nm. The electrical system has an immediate maximum torque, the Plug-in hybrids therefore react immediately to the action of the accelerator. The performances are just as impressive: the Class A 250 e completes the 0 to 100 km / h in just 6.6 seconds for a top speed of 235 km / h.
The latest generation of high energy density batteries
A lithium-ion battery with a total capacity of approx. 15.6 kWh serves as an energy storage unit for the electrical system. It can be recharged by alternating or direct current. The charging socket is located at the rear right of the vehicle. Compact rechargeable hybrids can be recharged on a 7.4 kW wall box with alternating current (AC) in 1 h 45 min for a charge of 10% to 100% of charge state (SoC = state of charge). With faster direct current (DC), the charging time is reduced to just 25 minutes for a 10% to 80% charge of SoC. Water-cooled batteries weighing approximately 150 kilograms are supplied by the Daimler group subsidiary Deutsche ACCUMOTIVE. For the third generation of Mercedes-Benz EQ Power plug-in hybrids, the group uses batteries with advanced cell chemistry. The jump from lithium iron phosphate (LiFePo) to lithium nickel manganese cobalt (Li-NMC) increased cell capacity from 22 to 37 Ah. As a result, it was possible to give the batteries a more compact design, benefiting the loading capacity and onboard space for the occupants.