It looks like it'll work great for race cars, because they're always either heavily accelerating, or heavily braking. It wouldn't work as well for normal drivers because once you 'charge' the flywheel (brake), you would have to use it shortly after, or the flywheel will slow down on its own.
It's probably electronically controlled, but it's not a regular hybrid system. The 'battery' in this case, is the flywheel, not something that stores electrical energy.
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