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.