The protection function of lithium battery（battery protection board)
is usually completed by the protection circuit boar
d and current devices such as PTC or TCO. The protection board is composed of electronic circuits, which can accurately monitor the voltage of the cell and the current of the charging and discharging circuit at any time in the environment of - 40 ℃ to + 85 ℃ and control the on-off of the current circuit immediately; PTC or TCO can prevent the battery from bad damage in high temperature environment.
The (battery protection board) usually includes control IC, MOS switch, precision resistor and auxiliary device NTC, ID memory, PCB, etc. The control IC controls the MOS switch on under all normal conditions to make the cell communicate with the external circuit. When the cell voltage or loop current exceeds the specified value, it immediately (tens of milliseconds) controls the MOS switch off to protect the safety of the cell.