Protection circuit board is the heart of battery pack, must to have to avoid battery pack from explosion, fire and damage.
This is a 20S 60A 60V bms for a LiFePO4 battery. It is not suitable for a Li-ion battery.
It will protect the battery pack from overcharging, over-discharging over-current and short circuit. With equilibrium function to keep each cell in balance and good service life.