Haldex type of 4 wheel drive do this, but in that case the rear wheels are disconnected at most times, they are engaged only when the car feels the need (hard a

Haldex type of 4 wheel drive do this, but in that case the rear wheels are disconnected at most times, they are engaged only when the car feels the need (hard acceleration, etc). It's not a big deal. In EV cars it is more complicated as they usually have an engine per wheel so you'd need a clutch at each wheel.