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Everything you need for a battery management system

Created by Ralf Hickl, Product Sales Manager Automotive Business Unit, Rutronik |   Knowledge

The battery management system (BMS) performs numerous indispensable tasks. This demands a whole range of different components. An overview.

The typical design of a battery cell management system is shown in Fig. 1: The energy cells are arranged here in series. For balancing purposes, a resistor with switching transistor is connected in parallel to each cell. These switches are controlled by balancing ICs that communicate with each other via a serial interface.

A superordinate microcontroller monitors and controls the cell management functions. A bidirectional electronic fuse also controls disconnection of the battery from the load or the charger on demand or in the event of a fault. Located at the top left is the current sensor technology, designed here as a shunt resistor with signal processing; alternatively, magnetic field-sensitive sensor ICs can assume this role.

Simplified diagram of cell and battery management (source: Rutronik)
Fig. 1: Simplified diagram of cell and battery management (source: Rutronik)