System and method for managing a battery of a vehicle

Abstract

The present invention relates to a system and method for managing a battery of a vehicle. The battery management system of the vehicle includes a first controller configured to control an ignition on (IG ON) state and an ignition 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 receiving power directly from a secondary battery at a periodic interval of a preset time calculated from a count value provided from the RTC for a preset reference time period when the ignition off state is turned on by the first controller, and monitor states of a primary battery and the secondary battery.

Description

TECHNICAL FIELD

[0001] The present application relates to a system and method for managing a battery of a vehicle, and more particularly, to a system and method for managing a battery of a vehicle, which prevents various problems occurring in a battery in a power-off state by effectively monitoring a state of the battery in advance through various controllers in the vehicle in a power-off state after the vehicle stops traveling. BACKGROUND

[0002] Generally, an eco-friendly vehicle driven by electric power generates power by driving a motor as an electric rotating device using electric power stored in a battery. The dynamic performance of the eco-friendly vehicle is closely related to the performance of the battery, and thus it is necessary to effectively monitor and manage the battery.

[0003] Generally, the battery of the eco-friendly vehicle is managed by a controller collectively referred to as a battery management system (BMS). The BMS collects various pieces of information for management of the battery (battery voltage, battery current, or battery temperature) from the battery and calculates various parameters for management of the battery by applying the collected information to various pre-stored algorithms.

[0004] A conventional vehicle battery management scheme is mainly performed in a state in which power is supplied to a controller called a battery management system (BMS), that is, an IG ON state or a state in which power is supplied to various controllers related to the battery (IG3 ON).

[0005] In the conventional vehicle battery management scheme, a main relay connected to the battery monitors the battery by IG ON in a state in which the battery is electrically connected to other components (for example, a power module for converting power of the battery and supplying the converted power to a motor or a charger to generate power to charge the battery) or by IG3 ON in a state in which power is supplied to various controllers related to the battery.

[0006] Accordingly, in the conventional vehicle battery management scheme, since information for management of the battery is collected in a state in which the battery is electrically connected to other components, there is a problem in that the state of the battery is not accurately monitored due to an influence of the other components on the collected information, or power is supplied to other controllers that do not need to be operated during the monitoring of the battery, thereby causing unnecessary power loss.

[0007] The contents of the related art described merely provide to help the understanding of the background of the present application, and should not be considered as equivalent to the prior art known to those having ordinary skill in the art. SUMMARY

[0008] An object of the present application is to provide a system and method of managing a battery of a vehicle for preventing an accident such as a battery fire in advance by effectively monitoring the battery in advance without wasting power in a state in which the vehicle is powered off.

[0009] According to one embodiment of the present application, a battery management system of a vehicle includes a main battery for storing driving power of the vehicle and a sub battery having a lower voltage output than the main battery and storing power for a plurality of controllers in the vehicle, the system including a first controller configured to control an IG ON state and an 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 receiving power directly from the sub battery at a preset time interval for a preset reference period when the IG OFF state is turned on by the first controller, and the second controller configured to monitor states of the main battery and the sub battery.

[0010] The second controller can be configured not to monitor the states of the main battery and the sub battery after the preset reference period elapses.

[0011] The second controller can be configured to operate in a power lock mode performed by receiving power directly from the sub battery during the preset reference period when the IG OFF state is turned on by the first controller, and to be woken up at a preset time interval after the power lock mode is terminated.

[0012] The second controller can be configured to turn off a main relay for connecting / disconnecting an output of the main battery when the IG OFF state is turned on by the first controller, and to check a condition not to monitor the states of the main battery and the sub battery.

[0013] As the condition, when a State of Charge (SoC) of the sub battery for supplying voltage of the first controller and the second controller cannot be checked, when the SoC of the main battery is lower than a preset reference value, when communication with the first controller or a low voltage DC-DC converter for reducing voltage of the main battery and applying the reduced voltage to the sub battery cannot be performed, or when the low voltage DC-DC converter fails, the second controller can be configured not to monitor the states of the main battery and the sub battery.

[0014] The second controller, after being woken up, can be configured to check whether a main relay connected to the main battery is short-circuited, and to start a preset time calculated in advance based on a count value provided by the RTC when a state in which the main relay is short-circuited changes to an IG OFF state.

[0015] When the SoC of the sub battery is less than or equal to a preset reference value as a result of monitoring the states of the main battery and the sub battery, the second controller, after being awakened, can be configured to turn on a main relay connected to the main battery and can operate a low-voltage DC-DC converter for reducing the voltage of the main battery and applying the reduced voltage to the sub battery, to charge the sub battery by reducing the voltage of the main battery and applying the reduced voltage to the sub battery.

[0016] When charging of the sub battery is terminated, the second controller can be configured to turn off the main relay and continue to maintain a preset time pre-calculated based on a count value provided by an RTC, rather than resetting the preset time.

[0017] The preset reference time period can be determined based on an analysis result of a Vehicle Customer Relation Management (VCRM) system for collecting and analyzing vehicle travel information, or a preset limit of a State of Charge (SoC) of the sub battery consumed by a dark current when the vehicle stops traveling.

[0018] According to another embodiment of the present application, a battery management method of a vehicle includes, when an external input that causes a vehicle to stop traveling is generated, controlling a plurality of controllers in the vehicle to be in a power-off state by a first controller, executing a power lock mode by a second controller, and turning off a main relay connected to a main battery for storing driving power of the vehicle, terminating the power lock mode, being awakened by directly receiving power from a sub battery for a preset reference time period at a period every 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 sub battery by the second controller.

[0019] The method can further include, after turning off the main relay, checking a condition of not monitoring the states of the main battery and the sub battery, and when the condition is satisfied, not monitoring the states of the main battery and the sub battery.

[0020] The not monitoring the states of the main battery and the sub battery can include, as the condition, when a State of Charge (SoC) of the sub battery for supplying voltage to the first controller and the second controller cannot be checked, when the SoC of the main battery is lower than a preset reference value, when communication with the first controller or a low-voltage DC-DC converter for reducing the voltage of the main battery and applying the reduced voltage to the sub battery cannot be made, or when the low-voltage DC-DC converter malfunctions, the second controller does not monitor the states of the main battery and the sub battery.

[0021] The monitoring of the states of the main battery and the sub battery can include the second controller checking whether a main relay connected to the main battery is short-circuited after the wakeup, and starting a preset time pre-calculated based on a count value provided by the RTC when a state in which the main relay is short-circuited is changed to a state in which the main relay is not short-circuited.

[0022] The monitoring of the states of the main battery and the sub battery can include the second controller turning on a main relay connected to the main battery after the wakeup when the SoC of the sub battery is less than or equal to a preset reference value as a result of the monitoring of the states of the main battery and the sub battery, and operating a low-voltage DC-DC converter for reducing a voltage of the main battery and applying the reduced voltage to the sub battery to charge the sub battery by reducing the voltage of the main battery and applying the reduced voltage to the sub battery.

[0023] The monitoring of the states of the main battery and the sub battery can include turning off the main relay and continuing to maintain a preset time pre-calculated based on a count value provided by the RTC when charging of the sub battery is terminated, instead of resetting the preset time. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a block diagram illustrating a configuration of a vehicle battery management system according to an embodiment of the present application.

[0025] Figure 2 is a schematic diagram illustrating a monitoring procedure of a vehicle battery management system according to an embodiment of the present application over time.

[0026] Figure 3 and Figure 4 is a flowchart illustrating a vehicle battery management method according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] Hereinafter, a system and a method of managing a battery of a vehicle according to an exemplary embodiment of the present application will be described in detail with reference to the accompanying drawings.

[0028] Figure 1 is a block diagram illustrating a configuration of a vehicle battery management system according to an embodiment of the present application.

[0029] Referring to Figure 1According to an embodiment of the present invention, the vehicle battery management system can include a main battery 13 for storing driving power of the vehicle and a sub-battery 15 having a lower voltage output than the main battery 13 and storing power for a plurality of controllers in the vehicle. The vehicle battery management system according to an embodiment of the present invention can further include a first controller 11 for controlling an IG ON state and an IG OFF state of the plurality of controllers and a second controller 12 having a Real Time Clock (RTC) 121, awakening the second controller 12 by receiving power directly from the sub-battery 15 at a preset time interval based on a count value provided from the RTC 121 when the IG OFF state is turned on by the first controller 11, and monitoring states of the main battery 13 and the sub-battery 15.

[0030] As shown in FIG. 1, the first controller 11 can be embodied as a Vehicle Control Unit (VCU) for controlling overall operations of the vehicle, and the second controller 12 can be embodied as a controller called a Battery Management System (BMS) that mainly monitors states of the battery and controls states of a main relay (MR) connected with the battery, etc., but the present invention is not limited thereto. For example, the second controller 12 can be embodied as a Hybrid Control Unit (HCU), a Low voltage DC-DC Converter (LDC) controller, etc., which is another controller included in the vehicle including a motor driven using energy stored in the battery. Figure 1 The main battery 13 can be a main battery (or a high voltage battery) of the vehicle that is charged by supplying energy to a driving motor for generating power of the vehicle or receiving energy regeneration of the driving motor.

[0031] The sub-battery 15 can be a battery for supplying voltage to various controllers including the first controller and the second controller and an electrical load in the vehicle, and can be a battery having a lower voltage output than the main battery 13.

[0032]

[0033] ​A low voltage DC-DC converter (LDC) for reducing a high voltage of the main battery 13 to a voltage of the sub battery 15 or a voltage corresponding to power of a controller or an electrical load in the vehicle can be provided between the main battery 13 and the sub battery 15. The second controller 12 can control the low voltage DC-DC converter 14, and can charge the sub battery 15 by reducing a voltage of the main battery 13 and supplying the reduced voltage to the sub battery 15.

[0034] According to an embodiment of the present application, the first controller 11 can control an IG ON state or an IG OFF state of a plurality of controllers in the vehicle based on a signal (e.g., a start button) input from the outside. For example, in the IG OFF state, when the driver generates an input of pressing a start button of the vehicle, the first controller 11 can recognize the input and can supply power to a plurality of other controllers in the vehicle to change a current state to the IG ON state. On the other hand, in the IG ON state, when the driver generates an input of pressing the start button of the vehicle, the first controller 11 can recognize the input and can interrupt the power supply to the plurality of other controllers in the vehicle to change a current state to the IG OFF state.

[0035] The second controller 12 can operate according to the IG ON or IG OFF state control performed by the first controller 11, and according to an input of the driver, immediately after the IG ON state is changed to the IG OFF state while the vehicle is stopped, the second controller 12 can turn off a main relay (MR) using a power latch function installed therein while maintaining the IG ON state for a predetermined time. Here, the main relay (MR) can be a relay for connecting or interrupting an output of the main battery 13 to a vehicle system or an output from the vehicle system to the main battery 13, and when the main relay (MR) is turned off and becomes an open state, all systems in the vehicle can become in a state of being unable to receive power from the main relay (MR).

[0036] The power latch function or power latch mode can be a function of maintaining a state of supplying power for a predetermined time using a power line directly connected to the sub battery 15, which supplies power as needed through the second controller 12 even if the first controller 11 performs the IG OFF control. That is, the second controller 12 can achieve an electrical connection with the sub battery 15 to directly receive power therefrom regardless of a power line (e.g., an IG line) controlled by the first controller 11. In general, power directly connected to the sub battery 15 can also be referred to as continuous power. According to an embodiment of the present application, the first controller 11 and the second controller 12 can be connected to the continuous power, and can continuously operate using a wake-up function that performs a predetermined time in each cycle to prevent the sub battery 15 from being discharged using the continuous power.

[0037] The second controller 12 can mainly measure the insulation resistance value of the main battery 13 and can monitor the voltage deviation between the battery cells included in the main battery 13, the degree of deterioration of the main battery 13, the voltage of the sub-battery 15, etc. to check for problems occurring in the main battery 13 and the sub-battery 15 after the vehicle stops traveling and is powered off.

[0038] The insulation resistance of the battery, the voltage deviation between the battery cells, and the degree of deterioration can be obtained or calculated using some of various schemes known in the art, and detailed schemes for obtaining or calculating the insulation resistance of the battery, the voltage deviation between the battery cells, and the degree of deterioration are not directly related to the spirit of the present application, and accordingly a detailed description thereof is omitted.

[0039] According to the control of the first controller 11, after the power-off (IG OFF) state of the vehicle is turned on, the second controller 12 can automatically wake up at a period of every preset time using a real-time clock (RTC) 121 installed therein and can monitor the main battery 13 and the sub-battery 15.

[0040] Figure 2 is a schematic diagram showing a monitoring process of a vehicle battery management system according to an embodiment of the present application over time.

[0041] When the driver who stops the vehicle from traveling inputs (startup button input in the power-on state) generation, the first controller 11 can turn on the power-off (IG OFF) state of powering off a plurality of controllers in the vehicle. As such, when the power-on (IG ON) state is converted into the power-off (IG OFF) state, the power-off (IG OFF) state can be turned on, and the second controller 12 can perform the power lock mode. The reference time for maintaining the power lock mode can be preset to about several hours.

[0042] When the power lock mode is terminated, the second controller 12 can be powered off, the second controller 12 can be woken up at a period of every preset time for a preset reference time period, and the second controller 12 can monitor the main battery 13 and the sub-battery 15 for a preset time.

[0043] For example, the reference time for monitoring the battery by the power-off and wake-up operation of the second controller 12 can be about several days. According to an analysis of a Vehicle Customer Relation Management (VCRM) system for collecting and analyzing various pieces of information on the vehicle travel, most drivers will start the vehicle again within at least 7 days after the vehicle stops traveling. In addition, the state of charge (SoC) of the secondary battery 15 consumed by the dark current after the vehicle stops traveling can be limited by each vehicle manufacturer. The reference time for monitoring the battery by the power-off and wake-up operation of the second controller 12 can be appropriately determined according to the analysis result of the VCRM system or a specification for managing the dark current applied to the secondary battery of the vehicle.

[0044] The second controller 12 can accumulate the number of times of waking up the second controller 12 per time period, can check the reference time for monitoring the battery, and can stop the monitoring when the reference time elapses.

[0045] The time interval for waking up the second controller 12 can be appropriately determined according to the lifespan of the memory 122 included in the second controller 12. For example, the number of times of writing capable of being performed for an EEPROM serving as the memory can be ensured to be a certain number of times or less. In consideration of the ensured number of times of writing for the EEPROM and the maximum number of times of writing performed by the EEPROM during the wake-up of the second controller 12, the wake-up time interval can be determined in such a manner that the maximum number of times of writing for the EEPROM during the expected lifespan of the vehicle is not greater than the ensured number of times of writing.

[0046] In addition, the time for monitoring the main battery 13 and the secondary battery 15 after the wake-up of the second controller 12 can be appropriately determined with reference to the number of times of performing a monitoring item (e.g., measurement of insulation resistance) for each battery or the time for performing the monitoring item.

[0047] According to various embodiments of the present application, the main battery 13 can be monitored in a state in which the vehicle is powered off (IG OFF) and the main battery 13 is not connected to the vehicle system, that is, in a state in which the main relay (MR) is turned off (short-circuited). Thus, the above-described monitoring can be performed when the state in which the main battery 13 is not connected to the vehicle system is maintained. During the above-described monitoring process, when the electrical connection state of the main battery 13 is changed, that is, when the main relay (MR) is turned on (closed), the battery monitoring according to various embodiments of the present application can be stopped and the monitoring process can be initiated, and when the main relay (MR) is turned off again, the battery monitoring can be restarted from the initial procedure for the battery monitoring, that is, the power lock mode of the second controller 12 is performed.

[0048] According to various embodiments of the present application, when the SoC of the sub battery 15 is lower than a preset reference value, the second controller 12 can charge the sub battery 15 by turning on the main relay (MR), driving the low-voltage DC-DC converter 14, lowering the voltage of the main battery 13, and supplying the lowered voltage to the sub battery 15. In this case, even if the main relay (MR) is turned on, the monitoring process can not be initiated. This is because, if the SoC of the sub battery 15 is low and the main relay is turned on to initiate the monitoring process, the charging of the sub battery 15 and the new monitoring process are repeatedly performed, and cannot be terminated within a preset time.

[0049] When the driver presses the vehicle start button to generate an input for shutting down the vehicle after the vehicle stops traveling and the controller of the first controller 11 controlling the vehicle is in an off (IG OFF) state, the second controller 12 can turn off the main relay (MR) while maintaining power using the power lock function, and then can determine whether the requirements for monitoring the main battery 13 are satisfied.

[0050] Here, as the requirements for monitoring the main battery 13, whether to calculate the state of charge (SoC) of the sub battery 15, the SoC of the main battery 13, the communication state between the controllers, etc. can be considered.

[0051] For example, when the second controller 12 cannot check the SoC of the sub battery 15 supplying power to the controllers 11 and 12, the first controller 11 and the second controller 12 can not be able to check whether sufficient power can be supplied for monitoring the main battery 13 in a state in which the sub battery 15 is not charged, and thus the monitoring of the main battery 13 can not be performed.

[0052] When the SoC of the sub battery 15 is lower than a preset reference value, the low-voltage DC-DC converter 14 can operate to charge the sub battery 15 using the energy stored in the main battery 13 and perform battery monitoring, and when the SoC of the main battery 13 is insufficient, if the sub battery 15 is charged, the SoC of the main battery 13 can be lowered and the vehicle can not be driven. Therefore, when the SoC of the main battery 13 is lower than a preset reference value, the monitoring can not be performed.

[0053] When communication between the first controller 11 and the second controller 12 or communication (e.g., CAN communication) between the second controller 12 and the low-voltage DC-DC converter 14 cannot be performed (e.g., CAN timeout), various data required to perform the monitoring cannot be exchanged, and thus the monitoring can not be performed.

[0054] When the low-voltage DC-DC converter 14 is determined to be faulty (e.g., an error code of the low-voltage DC-DC converter 14 is generated), the sub battery 15 cannot be charged, and thus the monitoring can not be performed.

[0055] Figure 3 and Figure 4 is a flowchart illustrating a vehicle battery management method according to an embodiment of the present application. The vehicle battery management method according to an embodiment of the present application can be performed by the above-described vehicle battery management system according to an embodiment of the present application.

[0056] Referring to Figure 3 and Figure 4 In a state in which the vehicle is parked, when the driver generates an input to stop the vehicle from traveling, the method can be executed from the step S11 of powering off the controllers in the vehicle by the first controller 11.

[0057] When the controllers enter a powered-off (IG OFF) state through the first controller 11, the second controller 12 can turn off the main relay (MR) while maintaining power using the power lock function (S12), and can check whether a requirement for performing monitoring is satisfied in a state in which the main relay (MR) is turned off (S13).

[0058] In the step S13, the second controller 12 can determine that monitoring is not performed in a case in which the SoC of the sub-battery 15 for supplying voltage to the first controller 11 and the second controller 12 cannot be checked, the SoC of the main battery 13 is lower than a preset reference value, the low-voltage DC-DC converter 14 for lowering the voltage of the main battery 13 and applying the lowered voltage to the sub-battery 15 malfunctions, or communication with the low-voltage DC-DC converter 14 or the first controller 11 cannot be performed.

[0059] When the requirement for performing monitoring is satisfied in the step S13, the power lock mode can be terminated (S14), and the second controller 12 can operate the RTC 121 installed therein, and then can turn off the second controller 12 (S15).

[0060] Then, the second controller 12 can be awakened using continuous power based on a count value of the RTC 121 (S21). The awakening performed in the step S21 based on the count value of the RTC installed in the second controller 12 can awaken only the second controller 12, and can not awaken the first controller 11. Accordingly, the power supply to other controllers or electrical loads can be interrupted by awakening the first controller 11, thereby reducing power consumption generated after the vehicle stops traveling.

[0061] Then, the awakened second controller 12 can determine whether the second controller 12 is awakened according to an input of the driver or the second controller 12 is awakened by the awakened first controller 11 powering on the vehicle (S22).

[0062] When the second controller 12 is awakened to perform battery monitoring based on the count of the RTC 121 installed therein, the second controller 12 can monitor the main battery 13 and the sub-battery 15 for a preset time (S23).

[0063] As a result of the monitoring, when the SoC of the sub-battery 15 is less than or equal to a preset reference value (S24), the second controller 12 can turn on the main relay (MR) and can operate the low-voltage DC-DC converter 14 to charge the sub-battery 15 to have an SoC value greater than the preset reference value.

[0064] When the SoC of the sub-battery 15 is greater than the reference value at step S24, or after charging the sub-battery 15 at step S25, the second controller 12 can check whether a preset reference time for performing the monitoring has elapsed (S26), when the reference time has not elapsed, the controller 12 can be powered off until the next monitoring is performed, when the reference time has elapsed, the controller 12 can terminate the monitoring process.

[0065] When the second controller 12 is awakened and powered on (S21) and it is determined that the reason for becoming the power-on state is the power-on (IG ON) state under the control of the first controller 11 (S22) based on the input of the driver, the second controller 12 can determine whether the main relay (MR) needs to be turned on (S27), and when the main relay (MR) is turned on, a counter can be started (S28). That is, when the first controller 11 is connected to the vehicle system by turning on the main relay (MR), the state of the battery can be changed, and the monitoring of the battery previously performed can be terminated.

[0066] After the counter is started (S28), when the vehicle becomes the power-off (IG OFF) state again through the first controller 11, the method can proceed to step S13 to perform the above-described monitoring process again from the start. After the counter is started (S28), instead of the vehicle becoming the power-off (IG OFF) state again through the first controller 11, the monitoring process can be terminated.

[0067] As described above, in the system and method of managing the battery of a vehicle according to various embodiments of the present application, in a state in which the vehicle stops traveling, the state of the battery can be monitored by awakening only the controller for managing the battery system of the vehicle based on the RTC installed therein periodically, and thus it is possible to prevent other controllers unrelated to the battery system from being awakened when the battery is monitored, thereby reducing power consumption due to battery monitoring in a state in which the vehicle stops traveling.

[0068] Specifically, in the system and method for managing a vehicle battery according to various embodiments of the present application, the number of times of performing battery monitoring can be appropriately determined as time elapses after the start of the power-off state, and thus the state of the battery can be effectively monitored while minimizing power consumption in the power-off state.

[0069] In the system and method for managing a vehicle battery, in a state in which the vehicle stops traveling, the battery state can be monitored by periodically waking up only a controller for managing the vehicle battery system based on an RTC installed in the controller, and thus it is possible to prevent other controllers unrelated to the battery system from being woken up when monitoring the battery, thereby reducing power consumption due to battery monitoring in the state in which the vehicle stops traveling.

[0070] Specifically, in the system and method for managing a vehicle battery, the number of times of performing battery monitoring can be appropriately determined as time elapses after the start of the power-off state, and thus the state of the battery can be effectively monitored while minimizing power consumption in the power-off state.

[0071] The first controller 11 can include a processor or a microprocessor. In addition, the first controller 11 can further include a memory. The above-described operations / functions of the first controller 11 can be embodied as computer-readable codes / algorithms / software stored on the memory, which can include a non-volatile computer-readable recording medium. The non-volatile computer-readable recording medium is any data storage device that can store data which can be subsequently read by a processor or a microprocessor. Examples of the computer-readable recording medium include a hard disk drive (HDD), a solid state drive (SSD), a silicon disk drive (SDD), a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc. The processor or the microprocessor can perform the above-described operations / functions of the first controller 11 by executing the computer-readable codes / algorithms / software stored on the non-volatile computer-readable recording medium.

[0072] Similarly, the second controller 12 can include a processor or a microprocessor. In addition, the second controller 12 can further include a memory. The above-described operations / functions of the second controller 12 can be embodied as computer-readable codes / algorithms / software stored on the memory, which can include a non-volatile computer-readable recording medium. The processor or the microprocessor can perform the above-described operations / functions of the second controller 12 by executing the computer-readable codes / algorithms / software stored on the non-volatile computer-readable recording medium.

[0073] Those skilled in the art will appreciate that the effects which can be achieved by the present application are not limited to what has been particularly described hereinabove and other effects of the present application will be more clearly understood from the foregoing detailed description with appropriate practices.

[0074] While the application has been shown and described with reference to particular embodiments thereof, it will be apparent to those of general skill in the art that various changes and modifications can be made to the application without departing from the spirit and scope of the application as defined in the appended claims.

Claims

1. A battery management system of a vehicle including a main battery for storing driving power of the vehicle and a sub battery having a lower voltage output than the main battery and storing power for a plurality of controllers in the vehicle, the battery management system comprising: a first controller configured to control a power-on state and a power-off state of the plurality of controllers; and a second controller including a real-time clock, the second controller configured to be woken up by receiving power directly from the sub battery every interval of a preset time calculated based on a count value provided from the real-time clock for a first preset reference time period when the power-off state is turned on by the first controller, and the second controller configured to monitor states of the main battery and the sub battery, wherein the second controller is configured to operate in a power lockout mode by receiving power directly from the sub battery during a second preset reference time period when the power-off state is turned on by the first controller, and to be woken up every interval of the preset time after the power lockout mode is terminated. The second controller is configured not to monitor the states of the main battery and the sub battery after the first preset reference time period elapses.

2. The battery management system of the vehicle according to claim 1, wherein, The second controller is configured to turn off a main relay for connecting / disconnecting an output of the main battery when the power-off state is turned on by the first controller, and to check a condition of not monitoring the states of the main battery and the sub battery.

3. The battery management system of the vehicle of claim 1, wherein, As the condition, when a state of charge of the sub battery for supplying voltages of the first controller and the second controller cannot be checked, when a state of charge of the main battery is lower than a preset reference value, when communication with the first controller or a low voltage DC-DC converter for reducing a voltage of the main battery and applying the reduced voltage to the sub battery cannot be made, or when the low voltage DC-DC converter fails, the second controller is configured not to monitor the states of the main battery and the sub battery.

4. The battery management system of the vehicle according to claim 3, wherein, The second controller, after being woken up, is configured to check whether the main relay connected to the main battery is short-circuited, and to start a preset time pre-calculated based on a count value provided from the real-time clock when a state of the main relay being short-circuited changes to a power-off state.

5. The battery management system of the vehicle of claim 1, wherein, When a state of charge of the sub battery is less than or equal to a preset reference value as a result of monitoring the states of the main battery and the sub battery, the second controller, after being woken up, is configured to turn on the main relay connected to the main battery and to operate a low voltage DC-DC converter for reducing a voltage of the main battery and applying the reduced voltage to the sub battery to charge the sub battery by reducing the voltage of the main battery and applying the reduced voltage to the sub battery.

6. The battery management system of the vehicle of claim 1, wherein, When charging of the sub battery is terminated, the second controller is configured to turn off the main relay and to continue to keep the preset time pre-calculated based on the count value provided from the real-time clock, instead of resetting the preset time.

7. The battery management system of the vehicle of claim 6, wherein, The first preset reference time period is determined based on an analysis result of a vehicle customer relationship management system for collecting and analyzing vehicle driving information, or a preset limit of the state of charge of the sub battery consumed by a dark current when the vehicle stops driving.

8. The battery management system of the vehicle of claim 1, wherein, ​ 9.A battery management method of a vehicle including a main battery for storing driving power of the vehicle and a sub battery having a lower voltage output than the main battery and storing power for a plurality of controllers in the vehicle, the method comprising: controlling, by a first controller, the plurality of controllers in the vehicle to be in a power-off state when an external input to stop driving of the vehicle is generated; executing, by a second controller, a power lock mode, and turning off a main relay connected to the main battery, the power lock mode being executed by directly receiving power from the sub battery during a second preset reference time period when the power-off state is turned on by the first controller; terminating the power lock mode, being woken up by directly receiving power from the sub battery every interval of a preset time calculated based on a count value provided from a real-time clock installed in the second controller for a first preset reference time period, and monitoring, by the second controller, states of the main battery and the sub battery. 10.The battery management method of the vehicle according to claim 9, further comprising: after turning off the main relay, checking a condition not to monitor the states of the main battery and the sub battery, and when the condition is satisfied, not monitoring the states of the main battery and the sub battery.

11. The battery management method of a vehicle according to claim 10, wherein the not monitoring the states of the main battery and the sub battery includes, as the condition, when a state of charge of the sub battery for supplying voltages of the first controller and the second controller cannot be checked, when a state of charge of the main battery is lower than a preset reference value, when communication with the first controller or a low-voltage DC-DC converter for lowering a voltage of the main battery and applying the lowered voltage to the sub battery cannot be made, or when the low-voltage DC-DC converter fails, the second controller not monitoring the states of the main battery and the sub battery.

12. The battery management method of a vehicle according to claim 9, wherein, the monitoring the states of the main battery and the sub battery includes: the second controller, after being woken up, checks whether a main relay connected to the main battery is short-circuited; when a state of the main relay being short-circuited is changed to a power-off state, the second controller starts a preset time pre-calculated based on a count value provided from a real-time clock.

13. The battery management method of a vehicle according to claim 9, wherein, the monitoring the states of the main battery and the sub battery includes: when a state of charge of the sub battery is less than or equal to a preset reference value as a result of monitoring the states of the main battery and the sub battery, the second controller, after being woken up, turns on the main relay connected to the main battery and operates a low-voltage DC-DC converter for lowering a voltage of the main battery and applying the lowered voltage to the sub battery to charge the sub battery by lowering the voltage of the main battery and applying the lowered voltage to the sub battery.

14. The battery management method of a vehicle according to claim 13, wherein, the monitoring the states of the main battery and the sub battery includes, when charging of the sub battery is terminated, turning off the main relay and continuing to maintain the preset time pre-calculated based on the count value provided from the real-time clock, instead of resetting the preset time.

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