Elsa: 2004 V70R Silver Metallic&Nordkap Back from Valhalla @ 357,098 miles
Car & Driver's blog has several good electric supercharger articles, about Ricardo's work on the prototype Ford Hyboost Focus diesel engine and the UK Controlled Power Technologies company, among others. They also deal with turbocompounding, as in Formula One's KERS.
Look, in theory, it could work. Sure, and powering a car by coal and steam works...but it's not a great idea. As Hounddogger said, you need so much volume to feed the engine, that compressing the air, storing it, and using it on demand is simply a non-starter from an efficiency standpoint. As Hounddogger said, the laws of thermodynamics paint a clear path, and using compressed air stored in a tank to feed the engine isn't on that path. you will never see an electric supercharger used in this method. Ever.
Also, we won't see production electric superchargers until we move to 48V electric systems, or if it's on a plug in hybrid with a higher voltage system.
With the 450 HP gasoline engine the Valeo is used to spin up the turbo from the cold side. With the power pulse the compressed air is used to spin up the turbo from the hot side.
'17 Volvo S60 Polestar '15 XC60T5 Polestarised
1 Exhaust in. Like the Volvo Power Pulse system.
2 Air in. As in the Volvo Triple Charge system.
3 Air out. As in the Audi/Valeo system (in series) or in parallel.
Electric superchargers can also be used alone, of course.