The Panasonic VL2020-1VCE is a 3V rechargeable Lithium coin cell with solder tags for vertical PCB mounting. It can be recharged approx 1000 times, has a high energy density and continuous trickle charging is not necessary because of a very low self discharge rate of just 2% per year.
This Vanadium Pentoxide Lithium Rechargeable VL2020 is a completely new coin-type Lithium battery with vanadium oxide for the positive pole, lithium alloy for the negative pole and a non-aqueous solvent for the electrolyte.
VL technology is mostly used for memory backup (computers, fax machines, mobile phones).
Nominal voltage of VL lithium batteries is 3V.