The battery pack is the most expensive single component in an EV and contains detailed monitoring and control to maintain a long, safe operating life. The BMS is responsible for monitoring individual cell health, balancing, operating pack heating and cooling systems, reporting state of charge and disconnecting power from the vehicle in a fault or collision.
This monitoring must continue even when the vehicle itself is parked and not in use. So that, for example, the pack heater can be engaged to maintain acceptable temperature in very cold conditions. This makes energy efficiency and minimizing the load on the HV battery critical to minimize range loss or worst case to prevent a dead vehicle.
PI's reinforced isolated flyback and non-isolated buck converter products are idea for generating internal low voltage supply rails. The extremely low no-load consumption and high efficiency reduce background discharge of the HV battery. Overall power loss is lower than relying on the 12 V system and provides the BMS the ability to continue to operate on loss of the 12 V system (discharged 12 V battery).