a battery against over-current charge, over-voltage charge, over-temperature, and under-
v
oltage discharge.
Lithium-ion polymer batteries appeared next. They are touted as being safer than lithium
ion because their electrolyte is composed of a dry polymer. In addition, rather than being
built using a conventional metal cell, they use a type of Mylar “ bag, ” making them much
more shapeable.
Unfortunately, their charge effi ciency is less than conventional lithium ion.
The next energy source for a mobile device may not be a true battery at all, but rather a fuel
cell . Rather ...
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