BMS(Battery Management System)
Rated voltage of Li-ion Battery Cell is 3.6V and charging voltage is 4.2V.
They are connected in series to generate voltages over 600V.
When multiple cells are connected in series, If one of the cells fails or deteriorates, the entire battery pack is affected. so Applied to the latest HEVs and EVs, BMS prevents overcharge, over-discharge, and overheating of individual cells and optimizes their lifetime.