The main function of a BMS is to control the set of high-voltage contactors delivering power. Neither the battery pack nor the BMS have direct control over the amount of power being delivered. The BMS communicates safe operating limits to the vehicle control unit (VCU) and enforces strict safety limits related to current, voltage, and temperature within the battery. If safety limits are exceeded, the BMS opens its contactors to prevent damage to the battery system.
Control Architecture #
The control architecture of the battery system is presented in the figure below.
Hibernium® battery systems feature a primary-secondary architecture. Each module within the battery pack has a secondary BMS board. This board measures voltages of each parallel cell string and reads temperature from temperature sensors distributed across each module. Additional active function of the secondary BMS board is cell balancing. It is achieved by connecting parallel strings of cells to a resistor dissipating excess energy.
Secondary BMS boards are connected to the primary BMS in a daisy-chain configuration. The primary BMS collects cell voltage and temperature information from the secondary BMS boards and aggregates data to determine the state of the battery pack.
BMS Power supply #
The Hibernium® BMS accepts 12V and 24V power supply. The total voltage range accepted is 9-32V.
Battery Management System (Vbatt / KL30):
- Peak Power: <120 W
- Nominal Power: <35 W
- Sleep Power (KL15 off): <0.02 W
Ignition (IGN / KL15):
- Worst Case Power: <6 W
- Nominal Power: <1 W
