Battery management system is vital for EVs

To ensure that electric vehicles run to their full potential without any harm to the battery, a management system is required. This is where Battery Management System (BMS) comes into play. The system helps prevent thermal runaway, adds to the health of battery and monitors functions like voltage and optimal coolant flow. In the long run, the system also helps improve battery life and overall operation. 

Most electric vehicles are powered by lithium-ion batteries that have a high charge density. These battery packs, despite their small size, can be extremely unstable

The primary function of a BMS is to protect the battery and prevent any operation that exceeds its safety limit. It monitors the battery pack’s State of Charge (SOC) as well as its overall health

Over the last decade, electric mobility and the popularity of electric vehicles (EVs) has grown rapidly and this trend shows no signs of losing steam. When EVs are viewed as a percentage of total vehicle sales, it is clear that the future is electric and that the era of Internal Combustion Engine (ICE) is coming to an end.

Most electric vehicles are powered by lithium-ion batteries that have a high charge density. These battery packs, despite their small size, can be extremely unstable. As a result, these batteries should never be overcharged or allowed to discharge completely. Thermal runaway occurs when the current flowing through the battery during charging causes the cell temperature to rise drastically.

Thermal runaway can reduce the battery’s lifespan and capacity. To prevent this from happening, we require a management system to monitor the voltage and current of the EV charging. Many cells are assembled to form a battery pack in an electric vehicle and each cell must be individually monitored for safety and efficiency. To cater to this, a specially designed system known as the Battery Management System (BMS) is used in EVs.

The primary function of a BMS is to protect the battery and prevent any operation that exceeds its safety limit. It monitors the battery pack’s State of Charge (SOC) as well as its overall health. BMS also manages battery optimisation through cell balancing, which improves battery life in the long run. The BMS will also keep track of voltage, temperature, and coolant flow. Its primary function is to ensure that the battery operates within the safety parameters. Because a battery pack is made up of 3V cells, the BMS must ensure that the cells in the pack are not discharged beyond this mark.

The charging process is divided into two stages. Constant Current (CC) is the first stage in which the charger provides constant current to charge the battery. The Constant Voltage (CV) is where a constant voltage is supplied to the battery at a very low current. The BMS ensures that these functions run smoothly.

The BMS also assists in indicating and displaying to the driver the current state of charge in the battery. The voltage and current measurements are made using algorithms that calculate the battery pack’s SOC. Coulomb Counting is one of the methods which measures the battery discharge and integrates the discharging current over time to estimate SOC.

Source: EVCD