Charging the future of transportation
Lerato Matebese reports on BMW’s future powertrains
IN LAST week’s report on the BMW Efficient Dynamics workshop I attended in Munich recently, we discussed some of the core pillars of the technology that included weight reduction, aerodynamics and engine efficiency. The latter brings me firmly to this week’s topic, which entails electrification of the powertrain that runs both hybrid and fully electric vehicles.
Now avid readers of Motor News who will recall my trip to Munich in 2009 where I managed to drive the fully electric Mini E, which was part of the maker’s assessment on the feasibility of the technology, will recall how suitably impressed I was.
It is certainly all good and well when manufacturers manage to achieve zero emission vehicles, but not at the expense of driver enjoyment. Thankfully that was not the case with Mini E.
So then a couple of years on and the Munich boys are re-exploring and refining electric, hy- brid, and hydrogen power trains.
In the instance of the Active Hybrid 7 (based on the 7 Series) and X6 model, both of which are equipped with Active Hybrid technology. In layman’s terms this means that the power required for the electric drive functions is obtained by means of brake energy regeneration.
Plug-in hybrid concepts meanwhile enable charging of the vehicle with energy from the main power supply system. In both cases the achievable vehicle range in electrical operation only is highly dependent on the capacity of the storage systems.
Simply put, the electric motor influences the vehicle’s characteristics in terms of agility, power development and range, while the power electronics secure the effective interaction between the energy storage unit and the electric powertrain.
In the case of these key components for hybrid and electric vehicles, the company found it fitting to go the in-house development and production route.
To that end the technological expertise in the drive system sector can also be extended to the field of electric mobility. In this way, high-voltage storage units, electric motors and power electronics can be precisely adapted to the requirements of each model.
The said high-voltage storage unit’s flexible modular system can be configured for a specific model. In the ActiveHybrid 7, the energy supply to the mild hybrid system is said to be provided by a compact lithium-ion battery comprising of the 35 single cells, which is integrated into the luggage compartment. It delivers 0.8kWh of energy, providing a maximum vehicle output of 19kW.
Due to the available installation space of this conversion concept, the integration of the new BMW high-voltage storage unit into the BMW ActiveE required three storage units of different size and shape.
They are installed within the area of the centre tunnel, at the front and at the rear of the vehicle.
The storage units contain several modules of three different sizes, the designs of which have identical cell sizes, and structures, each of them having a different number of cells. The three storage units provide the ActiveE’s 125kW electric motor with some 30kWh of power.
As seen in the pilot project in the 1 Series hatch, the configuration has allowed a much more compact layout, which is indeed a far cry from the bulky setup found in the Mini E.
We could be seeing BMW’s first Active Hybrid locally in the form of the 5 Series model, although no exact timetables have been given. While zero emissions are integral to BMW’s Efficient Dynamics strategy, I have a distinct feeling that driver enjoyment will remain at the core of the company’s values.