What is an ebike battery BMS (Battery Management System) and what does it do?

[ebikesforum]

BMS (Battery Management Systems): most e-bike batteries have a computer inside called a BMS. This computer makes sure that all the cells stay charged to the same voltage and drain at the same rate. It also protects the battery from over-discharging (putting out too many Amps and overheating the cells). Some BMS also keep the cells from operating at too high or low temperatures.