My best guess:
You have a personal wireless basestation that you bind or pair up to your wireless 'battery' thingy, so your 'battery' only looks for power from your basestation.
Then, the power is sent and picked up by the 'battery' where it does its usual thing of powering the car.
If thats the case, imagine a race where the duration is limited by managing heat.....or your transmitter batteries?
Or another way is that the 'battery' is charged by placing it near or next to a charging pad, this technology already exists for mobile phones but the range is poor (less than 5 metres).
Lots of possibilties though.