JP2017024462A - Power supply device and method of controlling power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the stable supply of power supply electric power to a load since before an engine is started.SOLUTION: A power supply device mounted on a vehicle and supplying power supply electric power to a load has a sub battery 164 provided separately from a main battery 11 mounted on a vehicle, and having an electric capacity smaller than the main battery; supply means (a switch 168) for supplying electric power accumulated in the sub battery to the load, when the electric power cannot be sufficiently supplied from the main battery to the load or when a charging state of the main battery is insufficient; and charging means (a charging portion 161) for charging the sub battery by the electric power outputted from an alternator or the main battery. The supply means is started until an engine of the vehicle is started since a door lock of the vehicle was released or the door was opened, and the supply of the electric power from the sub battery is enabled.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply apparatus and a control method for the power supply apparatus.

  In recent years, vehicle by-wire technology has become widespread. In the by-wire technology, the operation of the accelerator, the brake, etc. is performed not by mechanical transmission but by transmission by an electric signal.

  With the spread of such a by-wire technology, the reliability of a battery that is a source for generating an electrical signal is becoming more important.

  Therefore, in the technique disclosed in Patent Document 1, a capacitor unit having a plurality of capacitors is provided, and the capacitor unit is charged when the operation of the vehicle starts, and is discharged when the operation of the vehicle ends. When the battery is abnormal, power is supplied from the capacitor unit to the electronic control unit. According to such a configuration, the reliability and safety of the power source of the vehicle can be improved.

JP 2004-322987 A

  By the way, in the technique disclosed in Patent Document 1, the capacitor unit is discharged at the end of the operation of the vehicle. For this reason, since the capacitor unit is not charged before the operation of the vehicle is started, there is a problem that electric power cannot be supplied.

  In particular, when sufficient power supply cannot be supplied from the battery to the brake system, if the brake is operated to start the engine, a kickback due to the backflow of hydraulic pressure occurs, which causes discomfort to the driver. is there.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a power supply apparatus and a control method for the power supply apparatus that enable stable power supply to a load before the engine is started. Yes.

In order to solve the above-described problems, the present invention provides a power supply device that is mounted on a vehicle and that supplies power to a load. A sub-battery, and supply means for supplying power stored in the sub-battery to the load when the main battery cannot sufficiently supply power to the load or when the main battery is not sufficiently charged And charging means for charging the sub-battery with electric power output from the alternator or the main battery, and the supply means after the door of the vehicle is unlocked or the door is opened, It is started before the vehicle engine is started, and power can be supplied from the sub-battery. And features.
According to such a configuration, it is possible to stably supply power to the load before starting the engine.

Further, the present invention is characterized in that the supply means supplies electric power stored in the sub-battery to a plurality of loads.
According to such a configuration, the load can be reliably operated by supplying stable power to the plurality of loads.

Further, the present invention is characterized in that the load is a brake system for braking the vehicle.
According to such a configuration, it is possible to prevent kickback from occurring by supplying stable power supply to the brake system.

Further, the present invention is characterized in that the supply means supplies power to the brake system when the brake pedal is operated by a predetermined amount or more at the time of starting the engine.
According to such a configuration, when the brake pedal is operated by a predetermined amount or more, kickback can be reliably prevented by supplying power to the brake system.

Further, according to the present invention, the load is a starter motor, and the supply means does not supply sufficient power from the main battery to the starter motor, or when the main battery is not sufficiently charged. Power supply power is supplied from a battery to the starter motor.
According to such a configuration, the engine can be reliably started even when sufficient power cannot be supplied from the main battery.

In the present invention, when the engine is started, the supply means supplies the voltage of the sub-battery to the load via a regulator for stabilizing the voltage.
According to such a configuration, even when the voltage of the main battery becomes unstable during cranking, stable power can be supplied to the load.

The present invention is characterized in that a timing for supplying electric power from both the main battery and the sub battery to the load is provided at least before and after the period during which the voltage of the sub battery is supplied to the load. .
According to such a configuration, it is possible to prevent noise and the like from occurring when the sub battery and the main battery are switched.

Further, the present invention is characterized in that after the supply power is supplied from the sub battery to the load by the supplying means, the charging means charges until the sub battery is fully charged. To do.
According to such a configuration, charging immediately after using the sub-battery can prevent lead sulfate from being generated in the sub-battery and shortening the life.

The supply means may prevent the sub battery from being discharged by dark current flowing from the sub battery to the load when the vehicle engine is stopped. The supply is cut off.
According to such a configuration, it is possible to prevent the life of the sub battery from being shortened by preventing discharge due to dark current.

In addition, the present invention is a power supply device that is mounted on a vehicle and supplies power to a load, and is provided separately from a main battery mounted on the vehicle, and has a smaller electric capacity than the main battery. In the method for controlling the power supply apparatus having the above, when the main battery cannot sufficiently supply power to the load, or when the main battery is not sufficiently charged, the power stored in the sub battery is supplied to the load. And a charging step of charging the sub-battery with electric power output from the alternator or the main battery, wherein the supplying step unlocks the vehicle door or opens the door. Power supply from the sub-battery until the vehicle engine is started. It becomes ready, characterized in that.
According to such a method, it is possible to stably supply power to the load before starting the engine.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the power supply device which can supply the stable power supply to a load before starting an engine, and the control method of a power supply device.

It is a figure which shows the structural example of the power supply device which concerns on 1st Embodiment of this invention. It is a figure which shows the detailed structural example of the auxiliary power supply part shown in FIG. It is a figure for demonstrating operation | movement of 1st Embodiment shown in FIG. It is a flowchart which shows an example of the process performed in 1st Embodiment shown in FIG. It is a figure which shows the structural example of the auxiliary power supply part which concerns on 2nd Embodiment of this invention. It is a figure which shows the structural example of the auxiliary power supply part which concerns on 3rd Embodiment of this invention. It is a figure for demonstrating operation | movement of 3rd Embodiment shown in FIG.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of First Embodiment FIG. 1 is a diagram showing a power supply system of a vehicle having a power supply device according to the first embodiment of the present invention. As shown in this figure, the vehicle power supply system includes an alternator 10, a main battery 11, a voltage sensor 12, a current sensor 13, a temperature sensor 14, a control unit 15, an auxiliary power supply unit 16, a diode 17, and a load 18. doing.

  Here, the alternator 10 is driven by an engine (not shown), generates AC power, converts it into DC power by a rectifier circuit, and charges the main battery 11.

  The main battery 11 is constituted by a secondary battery such as a lead storage battery, a nickel cadmium battery, a nickel hydride battery, or a lithium ion battery, and is charged by the alternator 10 to drive a starter motor (not shown) to start the engine. At the same time, power is supplied to the load 18 via the diode 17.

  The voltage sensor 12 detects the terminal voltage of the main battery 11 and notifies the control unit 15 of the terminal voltage. The current sensor 13 detects the current flowing through the main battery 11 and notifies the control unit 15 of the current. The temperature sensor 14 detects the temperature of the main battery 11 itself or the surrounding environment and notifies the control unit 15 of the detected temperature.

  The control unit 15 refers to the outputs of the voltage sensor 12, the current sensor 13, and the temperature sensor 14, detects the state of the main battery 11, and controls the power generation voltage of the alternator 10 to control the charging state of the main battery 11. To control. Further, the control unit 15 determines that sufficient power cannot be supplied from the main battery 11 to the load 18 or when the main battery 11 is not sufficiently charged (for example, SOC (State of Charge) is predetermined). If the threshold value is lower than the threshold value, the auxiliary power supply unit 16 is instructed to supply power to the load 18.

  As will be described later, the auxiliary power supply unit 16 has a sub-battery 164, and when the main battery 11 cannot sufficiently supply power to the load 18 or when the main battery 11 is not sufficiently charged, Electric power is supplied from the battery 164 to the load 18.

  The diode 17 prevents the power from flowing back from the auxiliary power supply unit 16 to the main battery 11 when the power supply power is supplied from the auxiliary power supply unit 16 to the load 18.

  The load 18 is, for example, a brake system for braking the vehicle. For example, the load 18 is a detection unit that detects an operation amount of a brake pedal, a braking unit that brakes a wheel, and an operation amount detected by the detection unit. And a drive unit for driving the brake unit accordingly.

  FIG. 2 is a diagram illustrating a detailed configuration example of the auxiliary power supply unit 16 illustrated in FIG. 1. As shown in FIG. 2, the auxiliary power supply unit 16 includes a charging unit 161, an auxiliary power supply control unit 162, a state detection unit 163, a sub battery 164, a voltage sensor 165, a current sensor 166, a temperature sensor 167, a switch 168, and a diode. 169.

  Here, the charging unit 161 charges the sub-battery 164 with the electric power output from the alternator 10 (or the main battery 11) based on the control of the auxiliary power supply control unit 162.

  The auxiliary power supply control unit 162 controls each part of the auxiliary power supply unit 16 based on the state of the sub-battery 164 detected by the state detection unit 163, the output voltage from the main battery 11, and the state of the vehicle.

  The state detection unit 163 refers to the outputs of the voltage sensor 165, the current sensor 166, and the temperature sensor 167, detects the state (for example, SOC) of the sub battery 164, and notifies the auxiliary power supply control unit 162 of the detected state.

  The sub battery 164 is configured by a secondary battery such as a lead storage battery, a nickel cadmium battery, a nickel hydrogen battery, or a lithium ion battery, for example. The sub battery 164 is constituted by a battery independent of the main battery 11 and is constituted by a battery having a smaller electric capacity than the main battery 11. More specifically, the main battery 11 has a capacity of about several tens Ah, whereas the sub battery 164 has a capacity of several Ah to several tens Ah. The main battery 11 is accommodated in the hood in front of the vehicle, but the sub-battery 164 is accommodated not in the bonnet but in, for example, a spare tire storage portion at the rear of the vehicle. Of course, it may be accommodated in a place other than this, but in order to extend the life of the sub-battery 164, a place where the temperature change is small is desirable. In addition, by arranging in a different location from the main battery 11, for example, in the event of a collision, even if one is damaged, power can be supplied from the other, so these are arranged in different locations from the viewpoint of risk distribution. It is desirable.

  The voltage sensor 165 detects the terminal voltage of the sub battery 164 and notifies the state detection unit 163 of it. The current sensor 166 detects the current flowing through the sub battery 164 and notifies the state detection unit 163 of it. The temperature sensor 167 detects the temperature of the sub battery 164 itself or the surrounding environment, and notifies the state detection unit 163 of it.

  The switch 168 includes, for example, a semiconductor switch or an electromagnetic switch (electromagnetic relay), and the on / off state is controlled by the auxiliary power control unit 162. When the switch 168 is controlled to be on, power is supplied from the sub battery 164 to the load 18.

  The diode 169 is a backflow prevention diode and prevents the power output from the main battery 11 or the alternator 10 from flowing back to the circuit inside the auxiliary power supply unit 16. As shown in FIG. 2, the diode 17 prevents the power supplied from the auxiliary power supply unit 16 from flowing backward to the main battery 11 or the like.

(B) Description of Operation of First Embodiment Next, operation of the first embodiment will be described. FIG. 3 is a diagram showing changes in voltage and the like at the start of the vehicle. If the driver approaches the vehicle and the vehicle door is opened at time t1 in a state where the vehicle is stopped, the control unit 15 detects this, and the auxiliary power supply control unit 162 of the auxiliary power supply unit 16 detects this. Instruct to start. As a result, the auxiliary power supply control unit 162 enters the “startup” state as shown in FIG. 3B, and a start-up process such as an initialization process is executed.

  When the auxiliary power supply unit 16 is activated, the state detection unit 163 detects the state of the sub battery 164 and determines whether it is normal. More specifically, the state detection unit 163 measures the terminal voltage of the sub-battery 164 with the voltage sensor 165, and determines that the voltage is within a predetermined range as normal. Or the state detection part 163 carries out the pulse discharge of the sub battery 164, for example with the discharge circuit which is not shown in figure, and calculates | requires the impedance of the sub battery 164 from the change of the voltage and electric current at that time. Then, the SOC is calculated from the obtained impedance, and when the calculated SOC is equal to or greater than a predetermined threshold, it is determined that the state of the sub battery 164 is normal.

  When it is determined that the state of the sub battery 164 is normal, the auxiliary power supply control unit 162 turns on the switch 168 and turns off the charging unit 161. As a result, the power supply power output from the sub battery 164 is supplied to the load 18 via the switch 168 and the diode 169. As a result, as shown in FIG. 3C, the auxiliary power supply unit 16 is in a state of supplying start-up power to the load 18.

  Next, at time t2, when a driver operates a brake pedal, which is a condition for starting the engine, power is supplied from the sub battery 164 to the load 18 as a brake system via the switch 168 and the diode 169. Is done. As will be described later, the sub-battery 164 is charged so that it is fully charged or close to it, so that sufficient power is supplied to operate the load 18 that is a brake system. For this reason, for example, even when the driver depresses the brake pedal strongly (for example, when the driver depresses with a force of 50 kgf or more that is likely to cause kickback), kickback does not occur.

  Next, when the driver gives an instruction to rotate the starter motor at time t3, the starter motor (not shown) is rotated and engine cranking is executed. At this time, a large inrush current flows at the start of rotation of the starter motor, and the current increases as the piston of the engine approaches top dead center. Therefore, the voltage of the main battery 11 has a plurality of voltages as shown in FIG. It will be in the state which has an extreme value and fluctuates. However, power is also supplied to the brake system from the auxiliary power supply unit 16, and the auxiliary power supply unit 16 is supplied with power from the sub battery 164 having a configuration independent of the main battery 11. Even when the voltage of the main battery 11 becomes unstable, a stable power supply is supplied to the brake system, so that, for example, the occurrence of kickback can be prevented.

  Next, when the engine starts rotating at time t4, the supply of power from the main battery 11 to the starter motor is stopped. When the engine starts to rotate, the driver finishes the operation of the brake pedal. When the operation of the brake pedal is finished, the control unit 15 detects this and notifies the auxiliary power supply unit 16 of it. The auxiliary power control unit 162 of the auxiliary power supply unit 16 stops supplying power from the sub battery 164 to the load 18 by turning off the switch 168. As a result, the supply of power from the main battery 11 to the load 18 is started instead of the supply of power from the auxiliary power supply unit 16 to the load 18 being stopped. At this time, since the starter motor finishes rotating and charging from the alternator 10 is started, the voltage of the main battery 11 becomes stable. For this reason, even if it starts with supply of the electric power from the main battery 11 instead of the auxiliary power supply unit 16, the voltage becomes unstable and, for example, kickback does not occur.

  When cranking is completed at time t4, the control unit 15 controls the alternator 10 to start power generation and starts charging the main battery 11. Further, the control unit 15 controls the auxiliary power supply control unit 162 to start charging the sub battery 164. More specifically, the auxiliary power supply control unit 162 controls the charging unit 161 to charge the sub battery 164 with the electric power generated by the alternator 10. In addition, as a charging method by the charging unit 161, constant current charging with a current value that does not shorten the life of the sub battery 164 can be performed. Further, by charging immediately after using the sub-battery 164, it is possible to charge while the lead sulfate generated by the discharge is soft, and to prevent the lead sulfate from growing into a hard crystal. Thereby, the life of the sub battery 164 can be extended.

  As described above, according to the first embodiment of the present invention, the auxiliary power supply unit 16 having the sub-battery 164 composed of the secondary battery is provided, and the auxiliary power supply unit 16 is activated and operated before the engine is started. Made possible. Thereby, for example, when the driver operates the brake pedal before starting the engine, it is possible to prevent the kickback from occurring, for example, by supplying power from the auxiliary power supply unit 16.

  In addition, during cranking, power is supplied from the sub-battery 164 configured independently of the main battery 11 to the load 18 that is a brake system, so that the voltage of the main battery 11 becomes unstable due to cranking. Even in such a case, the occurrence of kickback or the like can be prevented by supplying stable electric power to the brake system.

  In addition, after cranking is completed and power generation by the alternator 10 is started, the sub-battery 164 is quickly charged, so that lead sulfate can be prevented from growing into a hard crystal. The life can be extended.

  Next, details of the operation of the first embodiment will be described with reference to FIG. When the processing of the flowchart shown in FIG. 4 is started, the following steps are executed.

  In step S10, the auxiliary power supply controller 162 turns off the switch 168. As a result, since a dark current that is a weak current does not flow from the sub battery 164 to the load 18, it is possible to prevent the sub battery 164 from discharging.

  In step S <b> 11, the control unit 15 controls the auxiliary power supply control unit 162 to stop the operation of each unit of the auxiliary power supply unit 16. As a result, by stopping the operation of the portion receiving power from the sub battery 164, the power consumption of the sub battery 164 is suppressed, and the operation of the portion receiving power from the main battery 11 is stopped. Thus, power consumption of the main battery 11 can be suppressed.

  In step S12, the control unit 15 determines whether or not the door has been opened. If it is determined that the door has been opened (step S12: Yes), the process proceeds to step S13, and otherwise (step S12: No). ) Repeat the same process.

  In step S <b> 13, the control unit 15 controls the auxiliary power supply control unit 162 to start the operation of each unit of the auxiliary power supply unit 16. More specifically, the auxiliary power supply control unit 162 executes start-up processing such as initialization processing, and the state detection unit 163 detects the state of the sub-battery 164 to determine whether it is normal. As a result, the auxiliary power supply unit 16 becomes operable.

  In step S14, the auxiliary power control unit 162 turns on the switch 168. As a result, supply of power supply from the sub battery 164 to the load 18 is started.

  In step S15, the control unit 15 determines whether or not the IG is in an on state. If it is determined that the IG is in an on state (step S15: Yes), the control unit 15 proceeds to step S16, and otherwise ( In step S15: No), the same processing is repeated.

  In step S16, the starter motor is rotated by the electric power from the main battery 11, and the engine is cranked.

  In step S17, the control unit 15 determines whether or not the engine has been started. If it is determined that the engine has been started (step S17: Yes), the process proceeds to step S18, and otherwise (step S17: No). ) Returns to step S16 and repeats the same process as described above.

  In step S18, the auxiliary power controller 162 turns off the switch 168. As a result, the supply of power from the sub battery 164 to the load 18 is stopped.

  In step S19, the auxiliary power control unit 162 controls the charging unit 161 to charge the sub battery 164. More specifically, the auxiliary power supply control unit 162 refers to the SOC of the sub battery 164 detected by the state detection unit 163 and continues charging until the sub battery 164 reaches a fully charged state. As a charging method, for example, there is a method of charging with a constant current that does not shorten the life of the sub battery 164.

  In step S20, the control unit 15 determines whether or not the engine is stopped. If it is determined that the engine is stopped (step S20: Yes), the control unit 15 returns to step S10 and repeats the same processing as described above. In other cases, the process returns to step S19 to continue the charging process.

  According to the above processing, the operation described with reference to FIG. 3 can be realized.

  In the flowchart shown in FIG. 4, the charging process is not continued after the engine is stopped. For example, until the sub battery 164 is fully charged even after the engine is stopped. The charging process may be continued with the power of the main battery 11. According to such processing, even when the vehicle is used only for a short time, the sub battery 164 can be kept in a fully charged state, so that the life of the sub battery 164 can be extended.

(C) Description of Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the configuration other than the auxiliary power supply unit 16 shown in FIG. 5 is the same as that in FIG. Also, in FIG. 5, the same reference numerals are given to the portions corresponding to those in FIG. In FIG. 5, compared with FIG. 2, the switch 168 is changed to two switches 168-1 and 168-2, and the diode 169 is changed to two diodes 169-1 and 169-2. A load 18-1 is connected to the diode 169-1, and a load 18-2 is connected to the diode 169-2. The load 18-1 is connected to the main battery 11 via a diode 17-1, and the load 18-2 is connected to the main battery 11 via a diode 17-2.

  Here, the switches 168-1 and 168-2 are configured by, for example, semiconductor switches or electromagnetic switches, and are controlled by the auxiliary power supply control unit 162 to be turned on or off. The diodes 169-1 and 169-2 are backflow prevention diodes, and when power is supplied from the main battery 11 to the loads 18-1 and 18-2, the power flows back into the auxiliary power supply unit 16. To prevent. The load 18-1 is configured by a brake system as in the case of the first embodiment. The load 18-2 is, for example, a wiper, a blower motor, a steering motor, various lights (headlight, room light, courtesy light, backlight, etc.), various ECUs (Electric Control Unit), or a vehicle emergency call device (accident). In the event of an emergency, etc., it is configured by a device that automatically notifies the nearest police or fire department via an emergency call center. The diodes 17-1 and 17-2 are backflow prevention diodes that prevent the power supplied from the auxiliary power supply unit 16 from flowing back to the main battery 11 or the like.

  Next, the operation of the second embodiment will be described. The power supply operation for the load 18-1 is the same as that in the first embodiment, and a description thereof will be omitted. In the second embodiment, in FIG. 3, when the door is opened and the load 18-2 is operating, the switch 168-2 is turned on. When switch 168-2 is turned on, power can be supplied from sub battery 164 to load 18-2. For this reason, for example, when the voltage of the main battery 11 becomes unstable due to cranking, the power is supplied from the sub battery 164 to the load 18-2. Thereby, for example, in the case of a load having a motor or the like (for example, a wiper, a blower motor, a steering motor, or the like), it is possible to prevent the operation of the motor from becoming unstable and causing the driver to feel uncomfortable. Further, when the load 18-2 is various lights (headlight, room light, courtesy light, backlight, etc.), the voltage of the main battery 11 becomes unstable, so that the illuminance changes and the driver is affected. It is possible to prevent discomfort. Further, when the load 18-2 is various ECUs, it is possible to prevent the operation of the ECU from becoming unstable or not operating due to the voltage of the main battery 11 becoming unstable. Further, in the case of the vehicle emergency notification device, even when the vehicle is damaged due to a collision accident or the like and the main battery 11 becomes unusable, the main battery 11 is separated from the main battery 11. Since electric power can be supplied from the sub-battery 164 arranged in a different place to the vehicle emergency call device, reliable operation can be ensured. When the engine is stopped, the switch 168-2 is turned off, and the supply of power from the sub battery 164 to the load 18-2 is stopped.

  In the above description, the switch 168-1 and the switch 168-2 are described as an example in which the switch is turned on when the door is opened and the switch is turned off when the engine is stopped. However, the switch 168-1 and the switch 168-2 may be turned on or off at different timings. For example, when the load 18-2 is an ECU or the like, it is desirable to supply a stable voltage at the time of start-up. Therefore, when the door is opened, the switch 168-2 is turned on, and other loads are applied. On the other hand, for example, when the IG switch is turned on, the switch 168-2 may be turned on.

(D) Description of Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, the configuration other than the auxiliary power supply unit 16 shown in FIG. 6 is the same as that in FIG. Also, in FIG. 6, the same reference numerals are given to the portions corresponding to those in FIG. In FIG. 6, compared to FIG. 5, a switch 168-3, a diode 169-3, a switch 170, and a regulator 171 are added. Further, the diodes 17-1 and 17-2 are excluded, and the diode 17 is added to the load 18-1. Other configurations are the same as those in FIG.

  Here, the switch 170 is configured by a semiconductor switch or an electromagnetic switch, and is controlled to be turned on or off by the auxiliary power control unit 162. The regulator 171 is configured by a DC / DC converter or the like, and boosts or steps down the voltage of the main battery 11 or the sub battery 164 supplied from the charging unit 161 so as to be a constant voltage, and supplies the voltage to the switch 168-2.

  The switch 168-2 is controlled to be turned on or off by the auxiliary power supply controller 162. When the switch 168-2 is controlled to be turned on, the voltage output from the regulator 171 is supplied to the load 18− via the diode 169-2. 2 is supplied.

  The switch 168-3 is controlled to be turned on or off by the auxiliary power control unit 162. When the switch 168-3 is controlled to be turned on, the voltage output from the main battery 11 is supplied to the load 18 via the diode 169-3. -2.

  Next, the operation of the third embodiment of the present invention will be described. Note that the operation of supplying the power supply voltage to the load 18-1 is the same as that in the first embodiment, and a description thereof will be omitted.

  In the third embodiment, the load 18-2 is configured by, for example, a car audio or a car navigation system. The auxiliary power supply control unit 162 restarts the engine after so-called idling stop for improving the fuel efficiency by stopping the engine during idling, for example, when the driver gets on the board for the first time. In this case, the switch 168-2 is turned on and the switch 168-3 is turned off. As a result, the power of the sub battery 164 whose voltage is stabilized by the regulator 171 is supplied to the load 18-2. Therefore, even when the voltage of the main battery 11 becomes unstable due to cranking, the car audio or car It is possible to prevent the navigation system or the like from malfunctioning or generating noise. When the engine starts rotating, auxiliary power supply control section 162 turns off switch 168-2 and turns on switch 168-3. As a result, the power source power from the main battery 11 that has been stabilized after cranking is supplied to the load 18-2 to the load 18-2, so that the power consumption of the sub-battery 164 can be prevented.

  In the third embodiment, a switch 170 is newly provided. The switch 170 is controlled by the auxiliary power control unit 162 to be in an on state when the main battery 11 is normal, and to be in an off state when the main battery 11 is abnormal. Thereby, when the voltage on the main battery 11 side is higher or lower than normal, it is possible to prevent the auxiliary power supply unit 16 from being affected by an abnormal voltage on the main battery 11 side.

  As described above, in the third embodiment, since power is supplied to the load 18-2 via the regulator 171 when the engine is started, a car audio or car navigation system sensitive to voltage fluctuations malfunctions. Or noise can be prevented.

  In the above description, the regulator 171 outputs the stabilized power using the power of the sub-battery 164. However, the power of the main battery 11 may be used. Alternatively, the power of the main battery 11 may be used when the switch 170 is on, and the power of the sub battery 164 may be used when the switch 170 is off.

(E) Description of Modified Embodiment The above embodiment is an example, and it is needless to say that the present invention is not limited to the case as described above. For example, in the example of FIG. 3, the auxiliary power supply unit 16 is activated when the door is opened. For example, as shown by a broken line in FIG. 16 may be activated. Of course, it may be started at other timings until the engine is started. Alternatively, the auxiliary power supply unit 16 may be activated when the door is unlocked, which is the stage before the door is opened. In the case of a remote control key, the case where the door is unlocked means, for example, a case where the lock is released by receiving radio waves from the remote control key. Is inserted into the keyhole and unlocked.

  Further, in each of the above embodiments, a starter motor is not taken as an example of a load for supplying power from the sub-battery 164, but, of course, power may be supplied to the starter motor. More specifically, when the state of charge of the main battery 11 is not sufficient, it becomes difficult to rotate the engine until the engine is started by the starter motor. In such a case, the auxiliary power supply control unit 162 determines this. It may be detected and power may be supplied from the sub battery 164 to the starter motor. The conditions for supplying power from the sub-battery 164 include, for example, (1) supply each time, (2) the engine cannot be started once, and the starter motor is rotated twice or more. (3) There are cases where the state of charge of the main battery 11 falls below a predetermined threshold.

  Further, in each of the above embodiments, power is supplied from either the main battery 11 or the sub battery 164 to the load. For example, as shown in FIG. 7, the main battery 11 and the sub battery 164 are supplied. It is also possible to provide a timing for supplying power from both sides. More specifically, the example of FIG. 7 corresponds to the third embodiment shown in FIG. 6, and as shown in FIG. 7D, when an inrush current flows during cranking, the ignition is turned off. In this state, both the switch 168-2 and the switch 168-3 are turned on, and a status B state in which power is supplied from both the main battery 11 and the sub battery 164 is entered. During the cranking, the switch 168-2 is turned on, the switch 168-3 is turned off, and the power of the sub battery 164 is supplied to the load 18-2 via the regulator 171. It will be in the state of C. In other cases, the switch 168-2 is turned off, the switch 168-3 is turned on, and the power of the main battery 11 is supplied to the load 18-2. Become. As described above, by providing the status B to which power is supplied from both the main battery 11 and the sub battery 164, a logical sum circuit is formed by the diode 169-2 and the diode 169-3, and the power source with the higher voltage is supplied. Since power is supplied, the power supply voltage supplied to the load 18-2 can be made constant, and switching noise can be prevented from occurring at the time of switching. In the example of FIG. 7, the status B for supplying power from both the main battery 11 and the sub battery 164 is provided both before and after the status C, which is a section for supplying power from the sub battery 164 to the load 18-2. However, the status B may be provided at least before or after the status C.

  Further, in each of the above embodiments, when the engine is started, the occurrence of kickback is suppressed by supplying electric power from the sub battery 164 to the brake system. However, since kickback occurs when the brake pedal is depressed with a predetermined force or more, power is supplied from the sub-battery 164 to the brake system when the brake pedal is depressed with a predetermined force or more. It may be.

  In each of the above embodiments, the case where the number of loads is one or two has been described as an example. However, power may be supplied from the auxiliary power supply unit 16 to three or more loads.

  Further, in the flowchart shown in FIG. 4, it is assumed that the engine is started for the first time after the driver has boarded, but when the engine is started after the idling stop described above, the flowchart of FIG. You may make it perform the process of.

  In the third embodiment shown in FIG. 6, when the auxiliary power supply unit 16 stops operating, the switch 168-3 is turned on, and the power from the main battery 11 is supplied to the load 18-2. It may be supplied.

DESCRIPTION OF SYMBOLS 10 Alternator 11 Main battery 12,165 Voltage sensor 13,166 Current sensor 14,167 Temperature sensor 15 Control part 16 Auxiliary power supply part 17 Diode 18, 18-1, 18-2 Load 161 Charging part 162 Auxiliary power supply control part 163 State detection Part 164 Sub-battery 168, 168-1, 168-2, 168-3, 170 Switch 169, 169-1, 169-2, 169-3 Diode 171 Regulator

Claims (10)

In a power supply device mounted on a vehicle and supplying power to a load,
A sub-battery provided separately from the main battery mounted on the vehicle, having a smaller electric capacity than the main battery;
A supply means for supplying power stored in the sub-battery to the load when the main battery cannot sufficiently supply power to the load, or when the main battery is not sufficiently charged;
Charging means for charging the sub-battery with electric power output from an alternator or the main battery,
The supply means is activated between when the door of the vehicle is unlocked or when the door is opened and before the engine of the vehicle is started, and power can be supplied from the sub-battery. It becomes a state,
A power supply device characterized by that. The power supply apparatus according to claim 1, wherein the supply unit supplies power stored in the sub-battery to a plurality of loads. The power supply apparatus according to claim 1, wherein the load is a brake system for braking the vehicle. The power supply device according to claim 3, wherein the supply means supplies power to the brake system when a brake pedal is operated by a predetermined amount or more at the time of starting the engine. The load is a starter motor;
The supply means supplies power to the starter motor from the sub-battery when the main battery cannot sufficiently supply power to the starter motor or when the main battery is not sufficiently charged. The power supply device according to any one of claims 1 to 4, wherein: The said supply means supplies the voltage of the said sub-battery to the said load via the regulator for stabilizing a voltage, when starting the said engine. The power supply device described in 1. The timing for supplying electric power to the load from both the main battery and the sub battery is provided at least before and after the period during which the voltage of the sub battery is supplied to the load. The power supply device according to any one of the above. The power supply power is supplied from the sub-battery to the load by the supply means, and the charging means charges until the sub-battery is fully charged. The power supply device according to any one of the above. The supply means supplies power to the load in order to prevent the sub-battery from being discharged by a dark current flowing from the sub-battery to the load when the vehicle engine is stopped. The power supply device according to claim 1, wherein the power supply device is cut off. A power supply device that is mounted on a vehicle and supplies power to a load, the power supply device having a sub-battery provided separately from a main battery mounted on the vehicle and having a smaller electric capacity than the main battery In the method
A supply step of supplying power stored in the sub-battery to the load when the main battery cannot sufficiently supply power to the load or when the main battery is not sufficiently charged; and
Charging the sub-battery with electric power output from an alternator or the main battery, and
The supplying step is started from when the door of the vehicle is unlocked or when the door is opened until the engine of the vehicle is started, and power can be supplied from the sub-battery. It becomes a state,
A control method for a power supply device.

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