The battery protection board BMS is a circuit board that protects the battery. It is mainly composed of electronic circuits. It accurately monitors the voltage of the cell and the current of the charging and discharging circuit under the environment of -40°C to +85°C, and controls the on and off of the current circuit in time.

Ordinary lithium battery protection board usually include control ICs, MOS switches, resistors, capacitors and some auxiliary devices. The control IC controls the MOS switch under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the safety of the cell.

What are the functions of the lithium battery protection board/ battery management system(BMS)?

The lithium battery protection board is to protect the lithium battery. The lithium battery protection board has four major functions: overcharge, overdischarge, overcurrent, and reverse connection protection.

1) Overcharge protection function:

The overcharge protection function means that when a certain voltage is reached, it is forbidden to continue charging by the charger. The MOS tube that is about to control overcharge enters the off state and stops charging.

2) Over-discharge protection function:

The over-discharge protection function stops discharging the load when the battery voltage drops. The MOS tube that controls the over-discharge enters the off state, and it is prohibited from discharging. This process is just the opposite of the action during overcharge detection.

3) Overcurrent protection function:

The over-current protection function is to stop discharging the load when a large current is consumed. The purpose of this function is to protect the battery and the MOS tube to ensure the safety of the battery in the state. After the over-current detection, the battery will return to the normal state after being separated from the load, and can be recharged or discharged.

4) Short circuit protection function: