Why lithium battery must need PCM or BMS?

1) Overcharge protection function: overcharge protection function means that when a certain voltage (hereinafter referred to as overcharge detection voltage) is reached, the charger is prohibited to continue charging. That is, the MOS tube that controls overcharge will enter the off state and stop charging.

2) Over discharge protection function: over discharge protection function is to stop discharging the load when the voltage of the battery becomes low. The MOS tube with control over discharge will be turned off and prohibited from discharging. This process is exactly the opposite of the action of overcharge detection.

3) Over current protection function: over current protection function is to stop the discharge of the load when consuming a large current, the purpose of this function is to protect the battery and MOS tube, to ensure the safety of the battery in the working state. After the overcurrent detection, the battery recovers from the load and can be recharged or discharged.

Note:as a whole,they avoid Over Charge,Over Discharge,Short-Circuit Over Current,Over Voltage,Overload etc and have Balance Voltage etc functions which ensure safety.