JP6875911B2 - Vehicle battery controller - Google Patents

Description

The present invention comprises a vehicle battery controller, particularly a low voltage battery that powers a low voltage electrical load including the electrical load required to start the engine, and a high voltage capable of powering the low voltage battery. The present invention relates to a vehicle battery control device equipped with a battery.

A hybrid vehicle is a typical example of a vehicle in which a low-voltage battery and a high-voltage battery are mounted together. As a battery control device for this type of hybrid vehicle, for example, there is one described in Patent Document 1 below. This vehicle battery control device charges the low-voltage battery by supplying power from the high-voltage battery to the low-voltage battery every time the vehicle is parked for a predetermined time, whereby the low voltage is charged even when the vehicle is parked for a long period of time. It is said that it can prevent the battery from running out. When supplying power from the high-voltage battery to the low-voltage battery, of course, a voltage drop circuit such as a DCDC converter is interposed.

Japanese Unexamined Patent Publication No. 2014-156170

In modern vehicles, power is consumed by an electrical load connected to a low-voltage battery, that is, a low-voltage electrical load, even when parked. Charging the low voltage battery with the high voltage battery while the vehicle is parked, that is, charging the low voltage battery with the high voltage battery, while charging the electric load of the low voltage battery, that is, the low voltage electrical load. It will be powered by a high voltage battery. Therefore, in that state, the engine is started with the power of the high voltage battery. Vehicles equipped with an engine can generally charge a low voltage battery if the engine can be started.

However, while charging the low-voltage battery with the high-voltage battery while the vehicle is parked, supplying power to the low-voltage electrical load also consumes a large amount of power of the high-voltage battery by the amount of charging the low-voltage battery. Therefore, the period during which the engine can be started with the high-voltage battery may be shortened accordingly. Furthermore, in that state, when the power consumption of the high-voltage battery is accelerated, that is, 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 you continue to power the low-voltage electrical load, you will eventually be unable to start the engine.

The present invention has been made in view of the above problems, and an object of the present invention is to be able 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. The purpose is to provide a battery control device for a vehicle.

The vehicle battery control device according to claim 1 for achieving the above object is used as a vehicle auxiliary battery that supplies power to a low-voltage electrical load including an engine starting electrical load necessary for starting an engine. Vehicle parking in a vehicle battery control device comprising a low-voltage battery and a high-voltage battery as a drive battery for an electric motor that is a vehicle drive source capable of supplying power to the low-voltage electrical load. A battery remaining amount calculation unit that sometimes calculates the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery, and the calculated remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and the high voltage. Calculated by 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 remaining battery level is equal to or higher than the high-voltage battery remaining amount specified value. When the remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and 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 referred to as the low-voltage electrical. It is characterized by including a battery intermittent control unit that disconnects from the load and connects the high voltage battery only to the engine starting electrical load.

According to this configuration, when the remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is equal to or more than the specified value of the remaining amount of the high-voltage battery, the low-voltage battery is low-voltage electricity. The high voltage battery is connected to the low voltage electrical load while being cut off from the target load. Therefore, when the remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is equal to or more than the specified value of the remaining amount of the high-voltage battery, the low-voltage battery may be charged by the high-voltage battery. Therefore, 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 extended.

In addition to this, if the remaining amount of the low voltage battery is less than the specified value of the remaining amount of the low voltage battery and 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 low voltage electrical. The high voltage battery is connected only to the engine starting electrical load while being disconnected from the load. Therefore, if the remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and 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 electricity other than the engine starting electrical load is applied. The target load can be cut off from the high-voltage battery, and the power consumption of the high-voltage battery can be further reduced accordingly. Therefore, even if the remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is less than the specified value of the remaining amount of the high-voltage battery, the period during which the engine can be started is further extended. can do. From the 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 remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is equal to or more than the specified value of the remaining amount of the high-voltage battery, but also the remaining amount of the low-voltage battery. Even if the amount is less than the specified value for the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is less than the specified value for the remaining amount of the high-voltage battery, the period during which the engine can be started can be extended. It is possible to start the engine as much as possible even when the vehicle equipped with the battery and the high-voltage battery is parked for a long period of time.

It is a schematic plan view which shows one Embodiment of the vehicle to which the battery control device for a vehicle of this invention is applied. It is a block diagram which shows the schematic structure of the power control unit and the low voltage electric load of FIG. It is a flowchart which shows the arithmetic processing performed by the power control device of FIG.

Hereinafter, an embodiment of a hybrid vehicle to which the 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. The engine 12, which is one of the drive sources of the vehicle, is arranged in the engine room in front of the vehicle, and the transmission 14 is connected to the rear of the engine 12. In this embodiment, for example, a horizontally opposed 4-cylinder engine is used for the engine 12, and a belt-type continuously variable transmission is used for the transmission 14. Note that FIG. 1 includes various accessories 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 installed in the engine room. The 12V battery 11 is generally a lead-acid 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 above-mentioned fuel pump, fuel injection device, and ignition device. The electrical load required to start the engine is defined as the electrical load for starting the engine. Further, an alternator (not shown) is attached to the engine 12, and the electric power generated by the alternator is stored in the 12V battery 11. Various control devices described later and electrical components such as air conditioners and lamps, which are not described in detail, are also connected to the 12V battery 11. The electrical load normally connected to these 12V batteries 11 is defined as a low voltage electrical load including the engine starting electrical load described above. The form of the engine 12 and the transmission 14 is not limited to the above-mentioned ones, and any form can be adopted.

A motor generator 13, which is another drive source, is provided in the transmission 14 of this embodiment. The motor generator 13 performs 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 driving force) is applied to the vehicle. Since the motor generator 13 is a drive source or a part of the drive source of the vehicle, a large amount of electric power is consumed or regenerated. 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. Further, in this embodiment, as will be described later, the electric power generated by the motor generator 13 can be supplied to and stored in the 12V battery 11. That is, electric power can also be supplied from the drive battery 15 to the low-voltage electrical load including the engine starting electrical 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 the drive pinion shaft 18 and the propeller shaft 20. It is transmitted to the rear axle via such means. In this embodiment, the 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 the front left and right wheels 10FL via the front left and right drive shafts 24FL and 24FR. It is transmitted to 10FR. Further, the driving force transmitted to the rear axle is divided by the 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.

The knuckles (hub housings) 30 of the front left and right wheels 10FL and 10FR, which are the steering wheels of the vehicle, are connected to the steering device 34 via the tie rods 32. As is well known, the steering device 34 is for steering the front left and right wheels 10FL and 10FR, which are steering wheels, by operating the steering wheel 36, and is configured by, for example, a well-known rack and pinion mechanism. An electric power steering device is adopted as the steering device 34 of this embodiment. The electric power steering device 34 is configured so 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 braking device 38 for applying a braking force to the wheels is attached to each of the wheels 10FL to 10RR. A well-known hydraulic or electric brake device can be used for the brake device 38. Therefore, braking force corresponding to the operation of the brake pedal by the driver is applied to each of the wheels 10FL to 10RR. A wheel speed sensor 39 for detecting the rotational speed of each wheel is attached to each of the wheels 10FL to 10RR.

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

Doors (including trunk lids or rear gates) (not shown) of this vehicle are provided with a door lock actuator 50 for locking and unlocking each door. Further, the vehicle is provided with a start switch 48, for example, on the instrument panel, which permits the operation of the vehicle. The start switch 48 permits the operation of the engine 12 by the on operation and also permits the start of operation as a vehicle. This start switch 48 corresponds to an ignition switch of a vehicle equipped with only an engine as a drive source. However, in a hybrid vehicle, the engine 12 is often stopped while the vehicle is stopped, so that the start switch 48 can be turned on. The operation of the engine 12 is permitted. When the start switch 48 is turned off, the operation of the engine 12 is forcibly stopped.

In this vehicle, 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, as in recent vehicles. 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 from, for example, a throttle opening degree and an engine rotation speed by the driver, and controls, for example, a fuel injection amount and an ignition timing so that the target engine torque is achieved. Further, when performing coordinated control with the power control unit 46 described later, for example, a target drive torque required by the driver and improving fuel efficiency is set so that the target engine torque assigned 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 from, for example, the traveling speed of the vehicle, the input rotation speed, and the throttle opening degree, and controls, for example, the belt pulley ratio in the transmission 14 so that the target gear ratio is achieved. ..

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

Further, the steering control unit 45 detects, for example, the steering torque by the driver with 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. As shown, the rotational 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 degree 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 required by the driver and improving fuel efficiency is set so that the target motor torque assigned to the motor generator 13 is achieved. It controls the rotational state of the motor generator 13. Further, when the vehicle is decelerating, the motor generator 13 is regeneratively operated so that the largest electric power is generated according to the state of charge of the drive battery 15.

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

Further, in this embodiment, when the keyless access control unit 47 can determine that the access key 52 is in the vehicle interior or is in the immediate vicinity of the start switch 48, the engine 12 is operated by the start switch 48 described above. Is allowed. Depending on the operating state of the start switch 48 (for example, whether or not the brake pedal is depressed), only the electrical components may be turned on, for example, the so-called accessory power supply. The transmission and reception of wireless signals between the keyless access control unit 47 and the access key 52 in an actual vehicle is more complicated, and is configured by, for example, providing an individual wireless 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 unit 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, as in the computer system. Further, similarly to recent vehicles, the control units 42 to 47 are configured to communicate with each other, perform cooperative control with each other, and exchange / share information. Actuators such as motors, valves, and pumps controlled by the control units 42 to 47 are operated by electric signals from the control units 42 to 47, respectively. That is, it may be considered that electric power is supplied to the actuator to be controlled via each of 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 electricity in the power control device 46a that controls arithmetic processing, the inverter 50 for controlling the operating state of the motor generator 13, and the electric power or the drive battery 15 generated by the motor generator 13. For the DCDC converter 52 for supplying the electric power to the 12V battery 11, the relay 54 for the drive battery that interrupts the inverter 50 and the drive battery 15, and the 12V battery that interrupts the inverter 50 or the drive battery 15 and the DCDC converter 52. It includes a relay 56, and a relay control circuit 58 that operates a drive battery relay 54 and a 12V battery relay 56. For example, when the motor generator 13 is driven by force, the inverter 50 converts the DC power of the drive battery 15 into AC power and creates a running speed and a frequency signal necessary for system control. The drive torque and electric power are controlled to accelerate or decelerate the vehicle.

Further, 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.

The vehicle also has a low battery switching relay 74 for selectively connecting all electrical components except the motor generator 13 and drive battery 15, that is, a low voltage electrical load to the 12V battery 11 or DCDC converter 52. The engine start securing relay 76 is provided, which cuts off the electric load other than the engine start electric load necessary for starting the engine from the power supply circuit among the voltage electric loads. That is, when the engine start securing 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 drive battery 15 side, both the drive battery relay 54 and the 12V battery relay 56 are connected.

In this embodiment, the engine control unit 42, the fuel pump (relay) 64, the fuel injection device (relay) 66, the ignition device (relay) 68, the starter (relay) 70, the transmission control unit 43, the power control unit 46, and the keyless The access control unit 47 is set as the engine starting electrical load. Therefore, the brake control unit 44, the steering control unit 45, and other electrical components (electrical load) 72 are set as low-voltage electrical loads other than the engine starting electrical load. A battery intermittent relay 78 that interrupts the 12V battery 11 with 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 securing relay 76, and the battery intermittent relay 78 are arranged in, for example, a fuse box, and in this embodiment, they are interrupted by the relay control circuit 58 according to the control signal from the power control device 46a. Opening and closing) is controlled. Further, the 12V battery 11 and the DCDC converter 52 are driven to detect the current and voltage of the 12V battery sensor 60 for detecting the current and voltage of the 12V battery 11 and the drive battery 15 converted to a low voltage, respectively. A battery sensor 62 is provided, and their detection signals are input to the power control device 46a.

Next, the arithmetic 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 arithmetic processing is executed by, for example, a timer interrupt processing at each predetermined sampling cycle set in advance. In this arithmetic processing, first, in step S1, it is determined whether or not the engine can be operated, and if the engine can be operated, the process proceeds to step S2. If not, the process proceeds to step S3. The determination as to whether or not the engine can be operated determines that the engine can be operated, for example, when the start switch 48 is in the ON state.

In step S2, it is determined whether or not the engine 12 is in operation, and if the engine 12 is in operation, 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 in the locked state, and if all the doors are in the locked state, the process proceeds to step S4, and if not, the process returns. In this step S3, in addition to the determination of the engine inoperability state in step S1, it is detected that the vehicle is parked, and while the vehicle is parked, the arithmetic processing after step S4 is performed.

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

In step S5, the 12V battery input / output possible power SOP _{12 is calculated from the 12V battery current I 12} and the 12V battery voltage V _12, and the process proceeds to step S6. As will be described later, the 12V battery input / output power SOP ₁₂ obtains the outputable power of the 12V battery 11 as the remaining electric power of the 12V battery 11.

_{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 possible 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. As will be described later, this drive battery input / output power SOP _DB obtains the outputtable power of the drive battery 15 as the remaining electric power of the drive battery 15.

In step S8, it is determined whether or not the 12V battery input / output power SOP ₁₂ is less than the preset 12V battery remaining amount specified value of 12V battery input / output power specified value SOP _12REF , and the 12V battery input / output power is determined. If the SOP ₁₂ is less than the 12V battery input / output power specified 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 the drive battery input / output power specified value SOP DBREF} , which is a preset drive battery remaining amount specified value, and the drive battery input / output power is available. If the SOP _DB is less than the drive battery input / output power specified value SOP _{DBREF, the process proceeds} to step S14, and if not, 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 securing relay 76 is connected 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, the drive battery relay 54 and the 12V battery relay 56 are both connected.

In step S13, the engine start securing relay 76 is connected and then returned.

Further, 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 drive battery 15 side, both the drive battery relay 74 and the 12V battery relay 56 are connected.

In step S15, the engine start securing relay 76 is disconnected and then returned.

According to this arithmetic processing, when it is detected that the vehicle is parked, the 12V battery current I ₁₂ and the 12V battery voltage V ₁₂ to the 12V battery input / output power SOP ₁₂ are calculated, and the drive battery current I _The drive battery input / output possible power SOP _DB is calculated from the DB and the drive battery voltage V _DV. As is well known, there are various methods for calculating the input / output power SOP. For example, as described in Japanese Patent Application Laid-Open No. 2005-160184, the internal impedance and the open circuit voltage are obtained from the current-voltage characteristics of the battery, and for example, the open circuit voltage obtained from the empirical rule and the battery charge state SOC (State of Charge). The battery charge state SOC is obtained from the correlation, and further, the input / output power SOP is obtained from the correlation between the battery charge state SOC obtained from the empirical rule and the input / output possible power SOP. Further, for example, as described in 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 current of the battery are obtained, and they are weighted to input / output power SOP. Ask for. The input / output power SOP can obtain input power and output power, but it is preferable to use output power as the remaining battery power. It is also possible to use the above-mentioned battery charge state SOC or battery deterioration state SOH (State of Health) as the remaining battery level. The battery deterioration state SOH can be obtained, for example, by dividing the integrated current value by the output efficiency, the design charge amount, and the charge usage rate.

Of these, if the calculated 12V battery input / output power SOP ₁₂ is 12V battery input / output power specified value SOP _12REF or more, which is a preset 12V battery remaining amount specified value, the battery switching relay 74 is on the 12V battery 11 side. At the same time, the engine start securing relay 76 is connected. Therefore, the low voltage electrical load is connected to the 12V battery 11 including the engine starting electrical load, and power is supplied from the 12V battery 11. Further, even during the operation of the engine 12, electric power is supplied from the 12V battery 11 to the low voltage electric load.

On the other hand, the calculated 12V battery input / output power SOP ₁₂ is less than the 12V battery input / output power specified value SOP _12REF , and the drive battery input / output power SOP _DB is the preset drive battery remaining amount specified value. When the battery input / output power specified value SOP _DBREF or more, the battery switching relay 74 is switched to the drive battery 15 side, and the engine start securing 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 I / O power SOP ₁₂ is less than the 12V battery I / O power specified value SOP _12REF and the drive battery I / O power SOP _DB is less than the drive battery I / O power specified value SOP _{DBREF, the battery} The switching relay 74 is switched to the drive battery 15 side, and the engine start securing relay 76 is disconnected. Therefore, as for the low voltage electrical load, only the engine starting electrical load is connected to the drive battery 15, and power is supplied from the drive battery 15 only to the engine starting electrical load via the DCDC converter 52.

Therefore, if the remaining amount of the 12V battery 11, which is a low-voltage battery, is equal to or higher than the specified value of the remaining amount of the 12V battery while the vehicle is parked, all the low-voltage electrical loads including the engine starting electrical load from the 12V battery 11 When the remaining amount of the 12V battery 11 becomes less than the specified value of the remaining amount of the 12V battery, the drive battery 15 which is a high voltage battery is transferred to all the low voltage electric loads including the engine starting electric load. Power is supplied. Further, if this state continues and the remaining amount of the drive battery 15 becomes less than the specified value of the remaining amount of the drive battery when the vehicle is parked for a long period of time, the low-voltage electric load excluding the engine start electric load is cut off from the power supply circuit. The drive battery 15 supplies power only to the engine start electrical load. For example, even if the remaining amount of the 12V battery 11 is low, the vehicle can be driven if the engine 12 can be started, and if the vehicle can be driven, the 12V battery 11 can be charged or driven by the alternator. The 12V battery 11 can be charged by the battery 15, and as a result, the life of the 12V battery 11 can be ensured.

As described above, in the vehicle battery control device of this embodiment, the 12V battery 11 is a low voltage battery that supplies power to the low voltage electric load including the engine starting electric load necessary for starting the engine 12. When the drive battery 15 is provided as a high-voltage battery capable of supplying power to a voltage electrical load, the remaining amount of the 12V battery 11 is less than the specified value of the remaining amount of the low-voltage battery and the remaining amount of the drive battery 15 is high voltage. When the remaining battery level is equal to or higher than the specified value, the 12V battery 11 is cut off from the low-voltage electric load, the drive battery 15 is connected to the low-voltage electric load, and the remaining amount of the 12V battery 11 is the low-voltage battery remaining amount specified. When the value is less than the value and the remaining amount of the driving battery 15 is less than the specified value of the remaining amount of the high voltage battery, the 12V battery 11 is cut off from the low voltage electric load and the driving battery 15 is connected only to the engine starting electric load.

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

If 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 less than the high-voltage battery remaining amount specified value, the low-voltage electrical load other than the engine starting electrical load is obtained. The load can be cut off from the drive battery 15, and the power consumption of the drive battery 15 can be further reduced accordingly. Therefore, even if 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 less than the high voltage battery remaining amount specified value, the period during which the engine can be started is further extended. 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 period of 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 matters specifying the invention described in the claims that are valid from the above description.

10FL-10RR Wheels 11 12V Battery (Low Voltage Battery)
12 engine 15 drive battery (high voltage battery)
42 Engine control unit (electrical load for starting the engine)
43 Transmission control unit (electrical load for starting the engine)
46 Power control unit (electrical load for starting the engine)
47 Keyless access control unit (engine start electrical load)
64 Fuel pump (relay) (Electrical load for starting the engine)
66 Fuel injection device (relay) (Electrical load for starting the engine)
68 Ignition system (relay) (electrical load for starting the engine)
70 Starter (relay) (Electrical load for starting the engine)
74 Battery switching relay 76 Engine start securing relay

Claims (1)

A low-voltage battery as an auxiliary battery for a vehicle that powers a low-voltage electrical load, including the engine-starting electrical load required to start the engine.
In a vehicle battery control device including a high voltage battery as a driving battery of an electric motor which is a driving source of the vehicle capable of supplying electric power to the low voltage electric load.
A battery remaining amount 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 specified value of the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is equal to or more than the specified value of the remaining amount of the high-voltage battery.
The low voltage battery is cut off from the low voltage electrical load and the high voltage battery is connected to the low voltage electrical load.
When the calculated remaining amount of the low-voltage battery is less than the specified value of the remaining amount of the low-voltage battery and the remaining amount of the high-voltage battery is less than the specified value of the remaining amount of the high-voltage battery.
It comprises 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 .
A vehicle battery control device, wherein the engine starting electrical load includes a fuel pump, a fuel injection device, an ignition device, a starter, and a control unit necessary for operating them.

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