http://www.e-cigarette-forum.com/forum/e-cig-technical-issues/8852-li-ion-batteries-truth.html
our cell phone batteries work a bit different. they have auto cut off circuit built into the phone as not to over charge. some also do somthing called a trickle charge.
"Trickle charging, or float charging, means charging a battery at a similar rate as to its self-discharging, thus maintaining a full capacity battery. Most rechargeable batteries, particularly nickel-cadmium batteries or nickel metal hydride batteries, have a moderate rate of self-discharge, meaning they gradually lose their charge even if they are not used in a device. Care must be taken, however, that if a battery regulator is not employed, the charge rate is not greater than the level of self-discharge, or overcharging and possible damage or leakage may occur"
lithium batteries also self discharge when not in use