Why would CPV be bothered finding their own energy storage...

Why would CPV be bothered finding their own energy storage solution when there are so many available already?

Everything from gravity, compressed air, stored heat, hydraulic pressure and kinetics is being used for that purpose, not forgetting multiple types of batteries.

I like this one developed for fast charging electric vehicles:

"Chakratec’s answer to the issues of EV charging speed (and the ability to recharge in times similar to refuelling an ICE car) are inspired by an old trick—or should we say, tech—the flywheel.

Its Chak Charge (C2) stores kinetic energy using a system that almost seems like magic: floating in mid-air using magnetic levitation, the flywheels spin in a vacuum chamber, doing away with friction and loss of momentum."

https://thedriven.io/2018/10/15/israeli-startup-proposes-fly-wheels-to-address-ev-charging-speeds/amp/?__twitter_impression=true