
A battery management system (BMS) is an electronic system that monitors and controls the performance of a battery. The main purpose of a BMS is to ensure that the battery operates safely and efficiently throughout its lifespan.
The BMS typically includes several components, such as sensors to measure the battery’s voltage, current, temperature, and state of charge (SOC). The BMS uses this information to regulate the battery’s charging and discharging cycles, preventing overcharging or over-discharging that can damage the battery or reduce its capacity over time.
The BMS may also include a controller that manages the flow of power between the battery and the device it powers, and a communication interface that allows the BMS to communicate with other systems in the device or with external monitoring systems.
In the below image the green section shows different functions of a Battery Management System in an electric car

Overall, the BMS plays a critical role in ensuring that batteries are used safely and efficiently in a wide range of applications, from small electronic devices to large-scale energy storage systems.