I think it is a energy cell that is akin to a capacitor and a battery.

Really it is a super capacitor that is low leakage. Maybe a 1F at 1V.

THey have been made for 30 or more years and have found a niche market
at last!

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder