JP2018171979A - Vehicular battery control device - Google Patents

Abstract

An engine can be started as much as possible even when a vehicle on which a low voltage battery and a high voltage battery are mounted is parked for a long period of time.
When a remaining amount of a 12V (low voltage) battery 11 becomes less than a specified value of a 12V battery remaining amount while the vehicle is parked, a battery switching relay 74 is switched to a drive (high voltage) battery 15 to start an engine start electric load. When all the low-voltage electrical loads including the power supply are supplied and the remaining amount of the drive battery 15 is less than the drive battery remaining amount specified value, the engine start securing relay 76 is disconnected to remove the engine start electrical load. The electric load is cut off from the power supply circuit, and power is supplied from the drive battery 15 only to the engine starting electric load.
[Selection] Figure 2

Description

  The present invention relates to a vehicle battery control device, and in particular, a low-voltage battery that supplies power to a low-voltage electric load including an electric load necessary for starting an engine, and a high voltage that can supply power to the low-voltage battery. The present invention relates to a vehicle battery control device equipped with a battery.

  A typical example of a vehicle in which a low voltage battery and a high voltage battery are mounted together is a hybrid vehicle, for example. As this type of battery control device for a hybrid vehicle, for example, there is one described in Patent Document 1 below. This vehicle battery control device charges a low-voltage battery by supplying power from the high-voltage battery to the low-voltage battery every time the vehicle parking time elapses for a predetermined time. It is said that the battery can be prevented from running out. When power is supplied from the high voltage battery to the low voltage battery, naturally, a voltage drop circuit such as a DCDC converter is interposed.

JP 2014-156170 A

  In recent vehicles, even when the vehicle is parked, electric power is consumed by an electrical load connected to the low voltage battery, that is, the low voltage electrical load. Charging a low voltage battery with a high voltage battery while such a vehicle is parked, i.e. charging a low voltage battery with a high voltage battery, to an electrical load of the low voltage battery, i.e., a low voltage electrical load. Power is supplied from a high voltage battery. Thus, in that state, the engine is started with the power of the high voltage battery. In a vehicle equipped with an engine, generally, a low voltage battery can be charged if the engine can be started.

  However, while the vehicle is parked, supplying power to the low-voltage electric load while charging the low-voltage battery with the high-voltage battery consumes as much power as the low-voltage battery is charged. Therefore, the period during which the engine can be started with the high voltage battery may be shortened accordingly. Furthermore, in that state, the power consumption of the high voltage battery is promoted, i.e., the remaining amount of the high voltage battery is reduced, and only the power for starting the engine remains in the high voltage battery. If power is continuously supplied to the low-voltage electric load, the engine cannot be started.

  The present invention has been made in view of the above-described problems, and its purpose is to start the engine as much as possible even when the vehicle on which the low-voltage battery and the high-voltage battery are mounted is parked for a long period of time. Another object of the present invention is to provide a vehicle battery control device.

  In order to achieve the above object, a vehicle battery control device according to claim 1 is a low-voltage battery for supplying power to a low-voltage electric load including an engine-starting electric load necessary for starting an engine; A battery control device for a vehicle including a high voltage battery capable of supplying electric power to an electrical load, wherein the battery remaining amount calculation unit calculates the remaining amount of the low voltage battery and the remaining amount of the high voltage battery when the vehicle is parked And when the calculated remaining amount of the low-voltage battery is less than a low-voltage battery remaining amount specified value and the remaining amount of the high-voltage battery is equal to or higher than the specified high-voltage battery remaining amount, the low-voltage battery is Disconnecting from the voltage electrical load and connecting the high voltage battery to the low voltage electrical load, and the calculated remaining amount of the low voltage battery is less than a specified value of the remaining low voltage battery and When the remaining amount of the high voltage battery is less than the specified value of the remaining amount of the high voltage battery, the low voltage battery is disconnected from the low voltage electrical load and the high voltage battery is connected only to the engine start electrical load. And a battery intermittent control unit.

  According to this configuration, when the remaining amount of the low voltage battery is less than the low voltage battery remaining amount specified value and the remaining amount of the high voltage battery is equal to or higher than the high voltage battery remaining amount specified value, the low voltage battery is set to the low voltage battery. The high voltage battery is connected to the low voltage electrical load. Therefore, the low voltage battery may be charged by the high voltage battery when the remaining amount of the low voltage battery is less than the low voltage battery remaining amount specified value and the remaining amount of the high voltage battery is equal to or higher than the high voltage battery remaining amount specified value. However, the power consumption of the high voltage battery can be reduced by that amount, and the period during which the engine can be started with the high voltage battery can be prolonged.

  In addition to this, if the remaining voltage of the low voltage battery is less than the specified value of the remaining low voltage battery and the remaining voltage of the high voltage battery is less than the specified value of the remaining high voltage battery, the low voltage battery is A high voltage battery is connected only to the engine starting electrical load while disconnected from the load. Therefore, if the remaining voltage of the low-voltage battery is less than the specified value for the remaining low-voltage battery and the remaining voltage of the high-voltage battery is less than the specified value for the remaining high-voltage battery, Therefore, the power load of the high-voltage battery can be further reduced. Therefore, even if the remaining voltage of the low voltage battery is less than the specified value of the remaining low voltage battery and the remaining amount of the high voltage battery is less than the specified value of the remaining high voltage battery, the period during which the engine can be started is further prolonged. can do. As described above, it is possible to start the engine as much as possible even when the vehicle on which the low voltage battery and the high voltage battery are mounted is parked for a long period of time.

  As described above, not only when the low-voltage battery remaining amount is less than the low-voltage battery remaining amount specified value and the high-voltage battery remaining amount is greater than or equal to the high-voltage battery remaining amount specified value, The amount of time that the engine can be started can be extended even if the amount is less than the low-voltage battery remaining amount specified value and the remaining amount of the high-voltage battery is less than the high-voltage battery remaining amount specified value. The engine can be started as much as possible even when the vehicle on which the battery and the high voltage battery are mounted is parked for a long time.

1 is a schematic plan view showing an embodiment of a vehicle to which a vehicle battery control device of the present invention is applied. It is a block diagram which shows schematic structure of the power control unit of FIG. 1, and a low voltage electrical load. It is a flowchart which shows the arithmetic processing performed with the power control apparatus of FIG.

  Hereinafter, an embodiment of a hybrid vehicle to which a vehicle battery control device of the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view of the hybrid vehicle of this embodiment. This vehicle is, for example, a station wagon type or a sports utility vehicle type passenger vehicle. An engine 12 as one of the drive sources of the vehicle is disposed in an engine room in front of the vehicle, and a transmission 14 is connected to the rear of the engine 12 in the vehicle. In this embodiment, for example, a horizontally opposed four-cylinder engine is employed for the engine 12 and a belt type continuously variable transmission is employed for the transmission 14. 1 includes various auxiliary devices for operating the engine 12, such as a fuel pump, a fuel injection device, an ignition device, and a starter (not shown).

  A 12V battery (low voltage battery) 11 for starting the engine 12 is also mounted in the engine room. The 12V battery 11 is generally a lead storage battery, and supplies the stored electric power to a starter (not shown) to start the engine 12. At that time, electric power is also supplied to the fuel pump, the fuel injection device, and the ignition device described above. These electric loads required for starting the engine are defined as engine starting electric loads. Further, an alternator (not shown) is attached to the engine 12, and electric power generated by this alternator is stored in the 12V battery 11. Various electrical devices such as an air conditioner and lamps, which will not be described in detail, are connected to the 12V battery 11. The electric load normally connected to the 12V battery 11 is defined as a low voltage electric load including the engine starting electric load described above. The forms of the engine 12 and the transmission 14 are not limited to those described above, and any form can be adopted.

  In the transmission 14 of this embodiment, a motor generator 13 which is another drive source is provided. The motor generator 13 performs a power running operation with the electric power from the drive battery 15 and charges the drive battery 15 with the electric power generated by the regenerative operation. During the power running operation of the motor generator 13, the vehicle is driven alone or together with the engine 12, and during the regenerative operation, a braking force (reverse drive force) is applied to the vehicle. The motor generator 13 is a driving source of the vehicle or a part of the driving source, and therefore consumes or regenerates a large amount of power. Therefore, the generated voltage of the drive battery 15 is larger than that of the 12V battery 11. Therefore, in this embodiment, the drive battery 15 corresponds to a high voltage battery. In this embodiment, as will be described later, the power generated by the motor generator 13 can be supplied to and stored in the 12V battery 11 as well. That is, electric power can be supplied also from the drive battery 15 to the low voltage electric load including the engine starting electric load.

  A center differential (center differential gear) 16 is provided in the transmission 14 described above, and the driving force divided by the center differential 16 is transmitted to the front axle via a drive pinion shaft 18 and the propeller shaft 20. Is transmitted to the rear axle via In this embodiment, a front differential (front differential gear) 22 is housed in the case of the transmission 14, and the driving force divided by the front differential 22 is transmitted to the front left and right wheels 10FL via the front left and right drive shafts 24FL and 24FR. 10FR. The driving force transmitted to the rear axle is divided by a rear differential (rear differential gear) 26 and transmitted to the rear left and right wheels 10RL and 10RR via the rear left and right drive shafts 28RL and 28RR.

  Knuckles (hub housings) 30 of the front left and right wheels 10FL, 10FR, which are steered wheels of the vehicle, are connected to a steering device 34 via a tie rod 32. As is well known, the steering device 34 is for turning the front left and right wheels 10FL, 10FR, which are steered wheels, by operating the steering wheel 36, and is constituted by, for example, a known rack and pinion mechanism. The steering device 34 of this embodiment employs an electric power steering device. The electric power steering device 34 is configured such that a steering assist force for assisting the driver's steering is applied by a motor (not shown) and the steering assist force can be adjusted.

  A brake device 38 for applying braking force to the wheels is attached to each of the wheels 10FL to 10RR. As the brake device 38, a known hydraulic or electric brake device can be used. Therefore, the braking force according to the brake pedal operation by the driver is applied to each of the wheels 10FL to 10RR. A wheel speed sensor 39 for detecting the rotation speed of each wheel is attached to each wheel 10FL to 10RR.

  The brake device 38 of this embodiment is also configured such that the braking force can be adjusted and controlled by the braking force adjusting device 40 regardless of the driver's intention. As this braking force adjusting device 40, for example, a known braking force adjusting device of a skid prevention device can be used. According to this type of braking force adjusting device 40, even when the driver does not step on the brake pedal, the braking force can be applied to the wheels 10FL to 10R, and the braking force can be adjusted. Further, in this type of braking force adjusting device 40, the applied braking force can be forcibly released as in a known ABS device.

  Doors (not shown) (including a trunk lid or a rear gate) of the vehicle are provided with door lock actuators 50 for locking and unlocking the doors. Further, this vehicle is provided with a start switch 48 that permits the operation of the vehicle, for example, on the instrument panel. The start switch 48 permits the operation of the engine 12 by an ON operation and permits the start of operation as a vehicle. The start switch 48 corresponds to an ignition switch for a vehicle equipped with only the engine as a drive source. However, in a hybrid vehicle, the engine 12 is often stopped when the vehicle is stopped. The operation of the engine 12 is permitted. Note that when the start switch 48 is turned off, the operation of the engine 12 is forcibly stopped.

  In this vehicle, as in recent vehicles, the engine 12 is driven by the engine control unit 42, the transmission 14 is driven by the transmission control unit 43, the braking force adjusting device 40 is driven by the brake control unit 44, and the steering device 34 is driven by the steering control unit 45. The motor generator 13 is controlled by the power control unit 46, and the door lock actuator 50 is controlled by the keyless access control unit 47.

  The engine control unit 42 sets a target engine torque based on, for example, a throttle opening and an engine rotation speed by a driver, and controls, for example, a fuel injection amount and an ignition timing so that the target engine torque is achieved. Further, when performing cooperative control with a power control unit 46 described later, for example, a target drive torque requested by the driver and improving fuel consumption is set, and the target engine torque allocated to the engine is achieved. For example, the fuel injection amount and ignition timing are controlled. Further, the transmission control unit 43 sets a target gear ratio based on, for example, the traveling speed of the vehicle, the input rotation speed, and the throttle opening, and controls, for example, a belt pulley ratio in the transmission 14 so that the target gear ratio is achieved. .

  The brake control unit 44 sets a target yaw rate based on, for example, the steering amount of the steering wheel 36 by the driver, and controls the braking force of each of the wheels 10FL to 10R so that the target yaw rate is achieved. The brake control unit 44 detects a wheel speed from a wheel speed sensor 39 attached to each of the wheels 10FL to 10RR. For example, when the detected wheel speed is smaller than a target wheel speed set from the vehicle body speed. In addition, the braking force of each of the wheels 10FL to 10RR is controlled so as to reduce the braking force of the wheel. When the brake control unit 44 performs cooperative control with a power control unit 46 described later, the braking force by the brake device 38 is equal to the braking force (reverse drive force) generated when the motor generator 13 is regeneratively operated. The braking force of each wheel 10FL-10RR is controlled so that it may become small.

  Further, the steering control unit 45 detects, for example, a steering torque by a driver by a torque sensor (not shown), sets a target steering assist force from the detected steering torque and the traveling speed of the vehicle, and outputs the steering assist force. Thus, the rotation state of a motor (not shown) is controlled. The power control unit 46 sets a target motor torque from, for example, the traveling speed of the vehicle and the throttle opening by the driver, and controls the rotational state of the motor generator 13 so that the target motor torque is achieved. Further, when performing coordinated control with the engine control unit 42, for example, a target drive torque requested by the driver and improving fuel efficiency is set, so that the target motor torque allocated to the motor generator 13 is achieved. The rotational state of the motor generator 13 is controlled. Further, when the vehicle is decelerating, the motor generator 13 is regeneratively operated so that the largest amount of electric power is generated according to the state of charge of the drive battery 15.

  The keyless access control unit 47 operates the door lock actuator 50 provided in each door (including the trunk lid or the rear gate) to open the door when the access key 52 possessed by the driver can be authenticated, for example. Lock and lock. Specifically, the keyless access control unit 47 exchanges radio signals with the access key 52, for example, and enables unlocking and locking of the door when the authentication information acquired from the access key 52 is authenticated. In order to substantially unlock and lock the door, a switch for door locking and a sensor for unlocking the door are provided on the vehicle side, or a switch for locking and unlocking the door is provided on the access key 52. Can be. Further, when unlocking / locking the door, a process of sounding an unillustrated answer back buzzer or blinking a hazard lamp may be added. Note that the door unlocking conditions include that all doors are locked. On the other hand, the door locking conditions include that all the doors are closed, the ignition is off (engine is stopped), and the access key 52 is not in the passenger compartment.

  Further, in this embodiment, when the keyless access control unit 47 can determine that the access key 52 is in the vehicle compartment or very close to the start switch 48, the engine 12 is operated by the start switch 48 described above. Is allowed. Depending on the operation state of the start switch 48 (for example, whether or not the brake pedal is depressed), for example, only an electrical component such as a so-called accessory power source may be turned on. Note that transmission / reception of radio signals between the keyless access control unit 47 and the access key 52 in an actual vehicle is more complicated, and is configured, for example, by including an individual radio transmission / reception device in addition to the keyless access control unit 47.

  These control units 42 to 47 are configured by mounting an arithmetic processing device such as a microcomputer and have an advanced arithmetic processing function. Therefore, these control units 42 to 47 are configured to include an input / output unit, a storage unit, and the like in addition to the arithmetic processing unit, similarly to the computer system. Further, like the recent vehicles, the control units 42 to 47 are configured to mutually communicate with each other, perform coordinated control with each other, and exchange and share information. Note that actuators such as motors, valves, and pumps controlled by the control units 42 to 47 are operated by electrical signals from the respective control units 42 to 47. That is, it may be considered that electric power is supplied to the actuator to be controlled via the control units 42 to 47.

  FIG. 2 is a block diagram showing a schematic configuration of the power control unit 46. As described above, the power control unit 46 stores power in the power control device 46a that performs arithmetic processing, the inverter 50 for controlling the operation state of the motor generator 13, and the electric power generated by the motor generator 13 or the drive battery 15. DCDC converter 52 for supplying the supplied power to the 12V battery 11, a drive battery relay 54 for intermittently connecting the inverter 50 and the drive battery 15, and a 12V battery for intermittently connecting the inverter 50 or the drive battery 15 and the DCDC converter 52 A relay 56 and a relay control circuit 58 that operates the drive battery relay 54 and the 12V battery relay 56 are provided. For example, when the power generator of the motor generator 13 is operated, the inverter 50 converts the direct current power of the drive battery 15 into alternating current power, and generates a frequency signal necessary for running speed and system control. The vehicle is accelerated and decelerated by controlling the drive torque and electric power.

  The relay control circuit 58 operates the drive battery relay 54 and the 12V battery relay 56 in response to a command from the power control device 46a.

  Further, the vehicle includes all electrical components except the motor generator 13 and the drive battery 15, that is, a battery switching relay 74 for selectively connecting a low voltage electric load to the 12V battery 11 or the DCDC converter 52, An engine start ensuring relay 76 that cuts off the electrical load other than the engine start electrical load necessary for starting the engine from the power supply circuit among the voltage electrical loads is provided. That is, when the engine start ensuring relay 76 is disconnected, only the engine start electrical load is connected to the 12V battery 11 or the DCDC converter 52 as a power supply circuit. When the DCDC converter 52 is connected to the power supply circuit, power is supplied from the drive battery 15. That is, when the battery switching relay 74 is switched to the driving battery 15 side, the driving battery relay 54 and the 12V battery relay 56 are both connected.

  In this embodiment, the engine control unit 42, fuel pump (relay) 64, fuel injection device (relay) 66, ignition device (relay) 68, starter (relay) 70, transmission control unit 43, power control unit 46, keyless An access control unit 47 is set as the engine starting electrical load. Accordingly, the brake control unit 44, the steering control unit 45, and other electrical components (electric loads) 72 are set as low voltage electrical loads other than the engine starting electrical load. In addition, a battery intermittent relay 78 for intermittently connecting the 12V battery 11 to the DCDC converter 52 is provided on the upstream side of the battery switching relay 74 in order to supply and store the electric power of the drive battery 15 to the 12V battery 11. The battery switching relay 74, the engine start ensuring relay 76, and the battery intermittent relay 78 are disposed, for example, in a fuse box. In this embodiment, the relay control circuit 58 performs intermittent (in accordance with a control signal from the power control device 46a). Controlled). Further, the 12V battery 11 and the DCDC converter 52 have a 12V battery sensor 60 for detecting the current and voltage of the 12V battery 11 and a drive for detecting the current and voltage of the drive battery 15 converted to a low voltage, respectively. A battery sensor 62 is provided, and detection signals thereof are input to the power control device 46a.

  Next, calculation processing for long-term parking control performed by the power control unit 46 of this embodiment, specifically, the power control device 46a of FIG. 2, will be described with reference to the flowchart of FIG. This calculation process is executed by a timer interrupt process, for example, at a preset predetermined sampling period. In this calculation process, first, in step S1, it is determined whether or not the engine is operable. If the engine is operable, the process proceeds to step S2, and if not, the process proceeds to step S3. For example, when the start switch 48 is on, it is determined that the engine can be operated.

  In step S2, it is determined whether or not the engine 12 is operating. If the engine 12 is operating, the process proceeds to step S9, and if not, the process returns.

  In step S3, it is determined whether or not all the doors are locked. If all the doors are in the locked state, the process proceeds to step S4, and otherwise returns. In this step S3, it is detected that the vehicle is parked together with the determination of the inoperable state of engine in step S1, and calculation processing after step S4 is performed while the vehicle is parked.

In step S4, the process proceeds to 12V battery current _{I 12} and the 12V battery voltage _{V 12} from the output signal of 12V battery sensor 60 reads, in step S5.

In step S5, it calculates a 12V battery output can power _{SOP 12} from 12V battery current _{I 12} and the 12V battery voltage _{V 12,} the process proceeds to step S6. The 12V battery input / output power SOP ₁₂ obtains the output power of the 12V battery 11 as the electrical remaining amount of the 12V battery 11, as will be described later.

In step S6, the drive battery current I _DB and the drive battery voltage V _DB are read from the output signal of the drive battery sensor 62, and the process proceeds to step S7.

In step S7, the drive battery input / output power SOP _DB is calculated from the drive battery current I _DB and the drive battery voltage V _DV , and the process proceeds to step S8. This drive battery input / output possible power SOP _DB obtains the output power of the drive battery 15 as the electrical remaining amount of the drive battery 15 as will be described later.

In step S8, it is determined whether the 12V battery input / output power SOP ₁₂ is less than a _preset 12V battery input / output power specified value SOP _12REF , which is a preset 12V battery remaining capacity specified value. If the SOP ₁₂ is less than the 12V battery input / output power prescribed value SOP _12REF , the _{process proceeds} to step S11, and if not, the _{process proceeds} to step S9.

In step S11, it is determined whether or not the drive battery input / output power SOP _DB is less than a drive battery input / output power specified value SOP _DBREF , which is a preset drive battery remaining power specified value, and the drive battery input / output power is determined. If the SOP _DB is less than the drive battery input / output power prescribed value SOP _DBREF , the _{process proceeds} to step S14. Otherwise, the _{process proceeds} to step S12.

  In step S9, the battery switching relay 74 is switched to the 12V battery 11 side, and then the process proceeds to step S10.

  In step S10, the engine start ensuring relay 76 is brought into a connected state and then returned.

  On the other hand, in step S12, the battery switching relay 74 is switched to the drive battery 15 side, and then the process proceeds to step S13. As described above, when the battery switching relay 74 is switched to the drive battery 15 side, the drive battery relay 54 and the 12V battery relay 56 are both connected.

  In step S13, the engine start ensuring relay 76 is brought into a connected state and then returned.

  Furthermore, in step S14, the battery switching relay 74 is switched to the drive battery 15 side, and then the process proceeds to step S15. As described above, when the battery switching relay 74 is switched to the driving battery 15 side, the driving battery relay 74 and the 12V battery relay 56 are both connected.

  In step S15, the engine start ensuring relay 76 is returned to the disconnected state.

According to this processing, when it is detected the vehicle is parked, the 12V battery output can power _{SOP 12} from 12V battery current _{I 12} and the 12V battery voltage _{V 12} is calculated, the driving battery current I Drive battery input / output power SOP _DB is calculated from _DB and drive battery voltage V _DV . As is well known, there are various methods for calculating the input / output possible power SOP. For example, as described in Japanese Patent Application Laid-Open No. 2005-160184, the internal impedance and the open voltage are obtained from the current-voltage characteristics of the battery. For example, the open voltage obtained from an empirical rule and the battery charge state SOC (State of Charge) The battery charge state SOC is obtained from the correlation, and the input / output capable power SOP is obtained from the correlation between the battery charge state SOC obtained from, for example, an empirical rule and the input / output capable power SOP. Further, as described in, for example, Japanese Patent Application Laid-Open No. 2006-105823, an open-circuit voltage power PV based on the open-circuit voltage of the battery and a current power PC based on the battery current are obtained and weighted to input / output power SOP. Ask for. The input / output power SOP can be input power and output power, but it is preferable to use output power as the remaining battery power. Note that the battery charge state SOC and the battery deterioration state SOH (State of Health) can be used as the remaining battery level. The battery deterioration state SOH can be obtained, for example, by dividing the current integrated value by the output efficiency, the design charge amount, and the charge usage rate.

Among these, if the calculated 12V battery input / output possible power SOP ₁₂ is equal to or _larger than the 12V battery input / output power specified value SOP _12REF which is a preset 12V battery remaining amount specified value, the battery switching relay 74 is on the 12V battery 11 side. And the engine start ensuring relay 76 is connected. Therefore, the low-voltage electrical load is connected to the 12V battery 11 including the engine start electrical load, and power is supplied from the 12V battery 11. In addition, electric power is supplied from the 12V battery 11 to the low-voltage electric load even during operation of the engine 12.

On the other hand, the calculated 12V battery input / output possible power SOP ₁₂ is less than the 12V battery input / output power prescribed value SOP _12REF , and the drive battery input / output capable power SOP _DB is a preset drive battery remaining amount prescribed value. If the battery input / output power prescribed value SOP _{DBREF is} exceeded, the battery switching relay 74 is switched to the drive battery 15 side and the engine start ensuring relay 76 is connected. Therefore, the low voltage electrical load is connected to the drive battery 15 including the engine start electrical load, and power is supplied from the drive battery 15 via the DCDC converter 52.

Further, if the calculated 12V battery input / output power SOP ₁₂ is less than the 12V battery input / output power specification value SOP _12REF and the drive battery input / output power SOP _DB is less than the drive battery input / output power specification value SOP _DBREF , the battery The switching relay 74 is switched to the drive battery 15 side, and the engine start ensuring relay 76 is disconnected. Therefore, only the engine start electrical load is connected to the drive battery 15 in the low voltage electrical load, and power is supplied only from the drive battery 15 to the engine start electrical load via the DCDC converter 52.

  Accordingly, if the remaining amount of the 12V battery 11 which is a low voltage battery is equal to or greater than the specified value of the remaining 12V battery while the vehicle is parked, all the low voltage electrical loads including the engine starting electrical load from the 12V battery 11 are obtained. However, when the remaining amount of the 12V battery 11 becomes less than the specified value of the remaining 12V battery, the drive battery 15 which is a high voltage battery supplies all low voltage electric loads including the engine starting electric load. Power is supplied. Furthermore, when this state continues and the remaining amount of the drive battery 15 becomes less than the drive battery remaining amount specified value when the vehicle is parked for a long time, the low voltage electric load except the engine starting electric load is cut off from the power supply circuit. Then, electric power is supplied from the drive battery 15 only to the engine starting electrical load. For example, even if the remaining amount of the 12V battery 11 is small, the vehicle can be driven if the engine 12 can be started. If the vehicle can be driven, the alternator can charge or drive the 12V battery 11. The battery 15 can charge the 12V battery 11, and as a result, the lifetime of the 12V battery 11 can be secured.

  Thus, in the vehicle battery control device of this embodiment, the 12V battery 11 as a low voltage battery for supplying power to the low voltage electrical load including the engine starting electrical load necessary for starting the engine 12, When the drive battery 15 is provided as a high voltage battery capable of supplying power to the voltage electrical load, the remaining amount of the 12V battery 11 is less than the low voltage battery remaining amount specified value and the remaining amount of the drive battery 15 is high voltage. If the battery remaining capacity is equal to or greater than the specified value, the 12V battery 11 is disconnected from the low voltage electrical load and the drive battery 15 is connected to the low voltage electrical load. The 12V battery 11 is disconnected from the low-voltage electrical load and driven when the remaining amount of the drive battery 15 is less than the high-voltage battery remaining amount specified value. The battery 15 is connected only to engine startup electrical load.

  Therefore, the 12V battery 11 may be charged by the drive battery 15 when the remaining amount of the 12V battery 11 is less than the low voltage battery remaining amount specified value and the remaining amount of the drive battery 15 is equal to or higher than the high voltage battery remaining amount specified value. However, the power consumption of the drive battery 15 can be reduced by that amount, and the period during which the engine can be started with the drive battery 15 can be extended.

  Further, when the remaining amount of the 12V battery 11 is less than the low voltage battery remaining amount prescribed value and the remaining amount of the drive battery 15 is less than the high voltage battery remaining amount prescribed value, the low voltage electrical load other than the engine starting electric load The load can be cut off from the drive battery 15, and the power consumption of the drive battery 15 can be further reduced by that amount. Therefore, even if the remaining amount of the 12V battery 11 is less than the low voltage battery remaining amount prescribed value and the remaining amount of the drive battery 15 is less than the high voltage battery remaining amount prescribed value, the period in which the engine can be started is further prolonged. can do. As a result, the engine 12 can be started as much as possible even when the vehicle on which the low-voltage battery and the high-voltage battery are mounted is parked for a long time.

  It goes without saying that the present invention includes various embodiments not described above. Therefore, the technical scope of the present invention is defined only by the invention-specifying matters described in the scope of claims which is appropriate from the above description.

10FL-10RR Wheel 11 12V battery (low voltage battery)
12 engine 15 drive battery (high voltage battery)
42 Engine control unit (engine starting electrical load)
43 Transmission control unit (engine starting electrical load)
46 Power control unit (engine starting electrical load)
47 Keyless access control unit (engine starting electrical load)
64 Fuel pump (relay) (engine starting electrical load)
66 Fuel Injection Device (Relay) (Engine Start Electric Load)
68 Ignition device (relay) (engine starting electrical load)
70 Starter (relay) (engine starting electrical load)
74 Battery switching relay 76 Engine start securing relay

Claims (1)

A low voltage battery that provides power to a low voltage electrical load, including an engine start electrical load required to start the engine;
In a vehicle battery control device comprising a high voltage battery capable of supplying power to the low voltage electrical load,
A remaining battery level calculation unit that calculates the remaining amount of the low voltage battery and the remaining amount of the high voltage battery when the vehicle is parked;
When the calculated remaining amount of the low-voltage battery is less than the low-voltage battery remaining amount specified value and the remaining amount of the high-voltage battery is equal to or higher than the high-voltage battery remaining amount specified value,
Disconnecting the low voltage battery from the low voltage electrical load and connecting the high voltage battery to the low voltage electrical load;
When the calculated remaining amount of the low-voltage battery is less than the low-voltage battery remaining amount prescribed value and the remaining amount of the high-voltage battery is less than the prescribed high-voltage battery remaining amount,
A vehicle battery control device comprising: a battery intermittent control unit that cuts off the low voltage battery from the low voltage electrical load and connects the high voltage battery only to the engine starting electrical load.

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