Primary lithium cells (i.e., AA and 2/3A) and rechargeable lithium
cells (i.e., 18650, 17500, and prismatic) are used in many portable
electronics applications, such as laptop or notebook computers.
Their popularity is based on the fact that they offer high energy
density, high capacity and long cycle life, with no memory effect.
Lithium cells are sensitive to faults caused by overcurrent and
overtemperature conditions that may result from accidental
shorting of the cell terminals and, in the case of rechargeable
lithium cells, abusive charging or charger failure. For this reason,
lithium cells generally require individual protection.
Their unique electrical characteristics and thin, flat form factor have
made PolySwitch PPTC (polymeric positive temperature
coefficient) annular disc devices the circuit protection device of
choice in a wide range of lithium cell applications.