BMS (Battery Management System)
Electronics and software embedded within each DC block that monitors cell voltages, temperatures, and state of charge. Protects cells from over-voltage, under-voltage, and thermal runaway, and communicates battery status to the Battery Plant Controller.
In energy storage
A utility-scale BESS typically uses a three-level BMS architecture: module-level monitoring, rack/string-level controllers, and a system-level BMS managing the complete DC block. The system BMS aggregates data and provides the communication interface to the unit controller or Power Plant Controller, sharing state of charge, state of health, alarm states, DoD restrictions, and hard-coded DC block operation limits. It also typically includes an O&M interface for service and maintenance access.