Fishman Fluence Pickups Active/Passive Design

I just came across these on the Duncan forum. They seem pretty interesting and have a lot of detail about frequency responses etc in the brochure but I would like to see a lot more about how they're made and what makes them so special!

Fishman Fluence Pickups

One key thing they have left out is how they recharge themselves.

Edit: I just read the Premier guitar article. It seems they charge via USB.

Premier Guitar