BMW has detailed the electric motor design of its all-new i7 electric sedan. This first electric 7 Series is more efficient than any other BMW.
The presentation of the new BMW 7 Series and its electric version i7 caused a lot of talk. For the design first, since the sedan takes up the modern codes of the brand. There is thus an oversized grille and headlights reduced to their simplest expression.
Inside, the Bavarian firm makes a perfect copy, with a mixture of comfort and luxury that we were able to discover exclusively. But it is under the hood and under the bodywork that this BMW i7 innovates in every respect.
The electric sedan’s electric motor no longer uses permanent magnets for the rotor, for various reasons. The first is ecological, since its composition is based on rare metals.
The second is ecological, because the price of neodymium oxide has doubled in recent years. In addition, the sourcing of these materials is 90% done in China, which is an ecological aberration.
The alternative that BMW has chosen to this technology is the electrically excited synchronous motor. Thus, the magnetic field making it possible to turn the rotor leaves its place to an electric motricity.
It is a set of brushes and a slip ring that make contact with the rotor. This is an already known technology, not necessarily acclaimed, but which BMW considered to be the best.
Regeneration and batteries at the center of attention
The BMW i7 has two such engines, one in the front and one in the rear. The electric sedan uses the energy recovery system of the brand’s other electric models, the i4 sedan and the iX SUV.
Energy management is certainly one of BMW’s most advanced technologies. Indeed, the German manufacturer uses navigation data to optimize regenerative braking in real time.
On other models, this system adjusts the level of regeneration according to the driver’s traffic management. On the BMW i7, the brand pushes this functionality to its climax, with the consideration of descents and the recognition of traffic lights to optimize regeneration.
But BMW did not optimize its luxurious “zero emission” sedan only during the driving phases. Thus, the management of the battery has progressed to limit peaks and drops in temperature during charging.
Thanks to this, the BMW i7 manages to carry out a more linear charge than other vehicles, provided that it has carried out the preheating. Of course, a heat pump is also present, as on many electric vehicles.