BMW i8 Motor Construction video

[SHiFT]

I saw this How It's Made the other day.

I'm not an expert in electric motors, but this seems very different from standard.

https://youtu.be/h2B1Xz_y8Co?t=1m36s

What do you think? Is their inexperience in the electric space showing here, or is this innovative?

SHiFT

 

[zener]

I wouldnt buy a ecar which not have inwheel DD hubmotors.
All other concepts don't make sense to me.

 

[Punx0r]

Looks like a 3 phase brushless inrunner. However, the staggered magnets seem unusual? Does that result in 144 poles or effectively infinite poles?

 

[fellow]

Number of magnets in a inrunner and outrunner rotors has nothing to do with number of stator motor poles, according to http://en.wikipedia.org/wiki/Outrunner and http://www.wattflyer.com/forums/archive/index.php/t-22343.html

I wouldnt buy a ecar which not have inwheel DD hubmotors.

They probably choosed a centralized motor because of the lower center of gravity and unsprung mass. Even some "weak" ebike motors have mass of 10kg+, thats unacceptable worsening of the suspension performance in a (sporty) car. I'm guessing that the ecar motor would weight a bit more because it is hard to extreme rev* a in-wheel motor and get the mass down. This because of the limited space to gear it down from the extreme revs, triple stage gearbox would simply not be enough:

I don't think that in wheel DD-motor would have enough "burnout capabilities", and unfortunatly that's what the marketing departement demands.
Second reason is that they simply have to keep the costs down, design team usually got more economic priority and fredom than the engineers do. Or they haven't tried hard enough...

Great video by the way!

* High revs=low mass