What is a Battery Management System?

A Battery Management System (BMS) is an electronic system that manages a rechargeable battery, such as a cell or battery pack. It is dedicated to the oversight of a battery pack, which is an assembly of battery cells, electrically organized in a row x column matrix configuration to enable delivery of a targeted range of voltage and current for a duration of time against expected load scenarios.

The oversight that a BMS provides usually includes:

⑴. Monitoring the battery.

⑵. Providing battery protection.

⑶. Estimating the battery’s operational state.

⑷. Continually optimizing battery performance.

⑸. Reporting operational status to external devices.

The BMS also controls the recharging of the battery by redirecting the recovered energy (i.e., from regenerative braking) back into the battery pack. Battery thermal management systems can be either passive or active, and the cooling medium can either be air, liquid, or some form of phase change.

Additionally, a BMS may calculate values such as:

①. Voltage: minimum and maximum cell voltage.

②. State of Charge (SoC) or Depth of Discharge (DoD), to indicate the charge level of the battery.

③. State of Health (SoH), a variously defined measurement of the remaining capacity of the battery as a percentage of the original capacity.

Overall, a BMS is a crucial component in managing and maintaining the health and efficiency of a battery pack.