How Battery Management System of an Electrical Vehicle Works

Automotive Battery Management Systems (BMS) should be able to meet vital options like voltage, temperature and current observance, battery state of charge (SoC) and cell equalisation of lithium-ion (Li-ion) batteries

Indeed, the most functions of battery Management System for electrical vehicles are:

• Battery protection in order to prevent operations outside its safe operational space.
• Battery monitoring by estimating the battery pack state of charge (SoC) and state of health (SoH) throughout charging and discharging.
• Battery optimization thanks to cell equalisation that improves the battery life and capability, therefore optimizing the golf range for hybrid (HEV), plug-in (PHEV) and full electrical vehicles (BEV).

BMS might shield its battery by preventing it from operational outside its safe operational space, such as:

• Over-current (may vary in charging and discharging modes)
• Over-voltage (during charging), particularly vital for lead–acid and Li-ion cells
• Under-voltage (during discharging)
• Over-temperature
• Under-temperature

EVs utilize Battery Management Systems for the most battery-based power offer, and HEVs use BMS for battery-side portion of power, complimentary to the inner combustion engine (ICE). BMS monitors the voltage, current, temperature, and wear levelling of battery cells. Individual lithium-ion battery cells are in the 3-4V range, they're connected in series to deliver higher voltage, and in parallel to increase performance.

To monitor the modules and cells, the Battery Management System might have a centralized design, or a distributed/modular design consisting of a BMS master and several other remote BMS units. In distributed BMS systems, remote units which monitors individual cells is also connected in parallel to the BMS master, or they'll be daisy-chained as series. In any case, connections from the battery modules or BMS remote units to the BMS master should be isolated to shield the BMS master from the battery voltages.