System and method of managing battery of vehicle

A battery management method of a vehicle, the method comprising:

• when an external input of stopping driving of the vehicle is generated, controlling a plurality of controllers in the vehicle in a power-off state, by a first controller;
• executing a power latch mode and turning off a main relay connected to a first battery for storing energy for generating power of the vehicle, by a second controller;
• and
• terminating the power latch mode, being woken up by directly receiving power from the secondary battery in every preset time period during a preset time calculated based on a count value provided from a real time clock (RTC) installed in the second controller, and monitoring states of the main battery and the secondary battery, by the second controller,
• wherein the monitoring includes:
• when a state of charge (SoC) of the second battery is equal to or less than a preset reference value as a monitoring result of the states of the main battery and the secondary battery, after woken up, turning on the main relay connected to the first battery and operating a low voltage DC-DC converter, for dropping a voltage of the first battery and applying the dropped voltage to the second battery, to charge the second battery by dropping the voltage of the first battery and applying the dropped voltage to the second battery, by the second controller.

A battery management system of a vehicle including a main battery for storing driving power of the vehicle and a secondary battery having a lower voltage output than the main battery and for storing electric power for a plurality of controllers in the vehicle, the battery management system comprising:

• a first controller configured to control a power-on (IG ON) state and a power-off (IG OFF) state of the plurality of controllers;
• and
• a second controller including a real time clock (RTC), and configured to be woken up by directly receiving power from the secondary battery in every preset time period during a preset time calculated based on a count value provided from the RTC when the power-off state is started by the first controller and to monitor states of the main battery and the secondary battery,
• wherein the second controller is configured to operate in a power latch mode that is executed by directly receiving power from the secondary battery during a preset reference time when the power-off state is started by the first controller, and to be woken up in every preset time period after the power latch mode is terminated.