The BMS plays a crucial role in the operation of electric vehicles (EVs) and other applications that rely on battery power. Its primary functions include safeguarding the battery from operating outside its safe limits, which involves preventing overcharging, over-discharging, overheating, and excessive current flows. By continuously monitoring the voltage, current, and temperature of individual cells, the BMS can detect and mitigate potential issues before they lead to battery failure or safety hazards.
One of the key features of a BMS is cell balancing. Battery packs consist of multiple cells connected in series and parallel configurations. Variations in cell capacities and resistances can lead to imbalances, where some cells may become overcharged or over-discharged relative to others. The BMS addresses this by redistributing charge among the cells, either through passive balancing (dissipating excess energy as heat) or active balancing (transferring energy from higher charged cells to lower charged ones). This balancing process helps maintain uniform cell voltage levels, enhancing the overall performance and lifespan of the battery pack.
Additionally, the BMS calculates the state of charge (SoC), which indicates the remaining battery capacity, and the state of health (SoH), which reflects the battery’s overall condition and ability to hold a charge. Accurate SoC and SoH estimations are essential for predicting the range of EVs, optimising energy use, and scheduling maintenance.
The BMS also provides critical data to the vehicle’s control systems and users, enabling informed decision-making regarding battery use and maintenance. It can interface with other vehicle systems to optimize energy efficiency, regenerative braking, and thermal management.