JP5245780B2 - vehicle - Google Patents

Description

  The present invention relates to a vehicle, and more particularly to a vehicle equipped with a power storage device configured to be rechargeable from the outside.

Japanese Patent Application Laid-Open No. 2007-209168 (Patent Document 1) is equipped with a power storage device that can be charged by an external power source, and activates a DC / DC converter for auxiliary equipment when the voltage of the power storage device for auxiliary equipment drops. An electric vehicle for charging an auxiliary power storage device is disclosed.
JP 2007-209168 A JP 2005-229665 A

  In recent years, it has been studied to configure a battery so that it can be charged from the outside even in a hybrid vehicle. However, it becomes necessary to start the vehicle system during the charging time, and accordingly, the time for charging and discharging the auxiliary battery also increases, and there is a concern that the auxiliary battery may be deteriorated or overcharged. The

  An object of the present invention is to provide a vehicle capable of reducing the deterioration of an auxiliary battery and the possibility of overcharging when charging from the outside of the vehicle.

  In summary, the present invention is a power storage device configured to be externally chargeable, a main load device that receives power supply from the power storage device, a voltage converter that converts the voltage of the power storage device, and voltage conversion The auxiliary battery to which the voltage converted by the converter is supplied, the electric load to which the power supply voltage is supplied from the voltage converter and the auxiliary battery, the sensor for detecting the state of the auxiliary battery, and the control of the voltage converter And a control device for performing. The control device converts the output target voltage of the voltage converter to the auxiliary charging voltage during the auxiliary charging period when the vehicle and the external power source are electrically coupled so that the power storage device can be charged from the outside. When the auxiliary battery is set and the auxiliary battery is charged, and an abnormality is detected in the auxiliary battery state by the sensor, a voltage different from the auxiliary charging voltage is set as the output target voltage of the voltage converter during the auxiliary charging period. To do.

  Preferably, the control device converts the fixed voltage to the voltage converter regardless of the state of the auxiliary battery detected by the sensor at an initial time before the auxiliary charging period and when the power storage device is charged from the outside. Set to the target output voltage.

  More preferably, the sensor includes a voltage sensor that detects the voltage of the auxiliary battery. The control device sets a voltage lower than the power supply voltage during normal operation of the electrical load after the initial time and before the auxiliary charging period as the output target voltage of the voltage converter, and reduces the voltage of the auxiliary battery. Whether the state of the auxiliary battery is abnormal is determined on the basis of the degree.

  Preferably, an air conditioner that receives power supply from the power storage device is further provided. The air conditioner is configured to be able to perform preliminary air conditioning before starting the vehicle by receiving power from the external power source when the vehicle and the external power source are electrically coupled. The control device sets the target voltage of the voltage converter to a voltage lower than the auxiliary charging voltage when a voltage drop of the auxiliary battery is detected by the sensor during the preliminary air conditioning.

  Preferably, the control device uses a first period for forcibly setting the output target voltage of the voltage converter to a fixed value when charging the power storage device from the outside, and a power supply voltage during normal operation of the electric load. A second period for determining an abnormality of the auxiliary battery by setting a lower voltage as the output target voltage of the voltage converter, an auxiliary charging period, and a voltage lower than the auxiliary charging voltage after the auxiliary charging period elapses. And a full charge maintaining period for maintaining the full charge of the auxiliary battery by setting the output target voltage to the output target voltage.

  According to the present invention, when plug-in charging is performed from the outside, deterioration of the auxiliary battery can be suppressed and the possibility of overcharging can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a block diagram showing a configuration of a vehicle 1 according to an embodiment of the present invention. The vehicle 1 is a hybrid vehicle that uses both a motor and an engine for driving wheels.

  Referring to FIG. 1, vehicle 1 includes front wheels 2FR, 2FL, rear wheels 2RR, 2RL, an engine 4, a planetary gear PG, a differential gear DG, and gears 5, 6.

  Vehicle 1 further includes a battery B1, a boosting unit 10 that boosts DC power output from battery B1, and inverters 20 and 30 that exchange DC power with boosting unit 10.

  Vehicle 1 further includes a motor generator MG1 that generates electric power by receiving mechanical power from engine 4 via planetary gear PG, and a motor generator MG2 whose rotating shaft is connected to planetary gear PG. Inverters 20 and 30 are connected to motor generators MG1 and MG2, and convert AC power and DC power from booster unit 10.

  Planetary gear PG is coupled to engine 4 and motor generators MG1 and MG2, and operates as a power split mechanism that distributes power between them.

  Planetary gear PG includes a sun gear, a ring gear, a pinion gear that meshes with both the sun gear and the ring gear, and a planetary carrier that rotatably supports the pinion gear around the sun gear. Planetary gear PG has first to third rotation shafts. The first rotating shaft is a rotating shaft of a planetary carrier connected to the engine 4. The second rotating shaft is a rotating shaft of a sun gear connected to motor generator MG1. The third rotating shaft is a rotating shaft of a ring gear connected to motor generator MG2.

  These three rotation shafts are connected to the rotation shafts of engine 4 and motor generators MG1, MG2, respectively. For example, engine 4 and motor generators MG1 and MG2 can be mechanically connected to the power distribution mechanism by making the rotor of motor generator MG1 hollow and passing the crankshaft of engine 4 through the center thereof.

  A gear 5 is attached to the third rotating shaft, and the gear 5 drives the gear 6 to transmit mechanical power to the differential gear DG. The differential gear DG transmits the mechanical power received from the gear 6 to the front wheels 2FR and 2FL, and transmits the rotational force of the front wheels 2FR and 2FL to the third rotating shaft of the planetary gear PG via the gears 6 and 5.

  Planetary gear PG determines the rotation of the remaining one rotation shaft in accordance with the rotation of two of the three rotation shafts. Accordingly, the vehicle speed is controlled by controlling the power generation amount of the motor generator MG1 and driving the motor generator MG2 while operating the engine 4 in the most efficient region, thereby realizing an overall energy efficient vehicle. Yes.

  It should be noted that a speed reducer for the rotating shaft of motor generator MG2 may be further incorporated in planetary gear PG.

  Booster unit 10 boosts the DC voltage received from battery B 1, and supplies the boosted DC voltage to inverters 20 and 30. Inverter 20 converts the supplied DC voltage into an AC voltage, and drives and controls motor generator MG1 when the engine is started. Further, after the engine is started, AC power generated by motor generator MG1 is converted to DC by inverter 20 and converted to a voltage suitable for charging battery B1 by boosting unit 10 to charge battery B1.

  Inverter 30 drives motor generator MG2. Motor generator MG2 drives front wheels 2FR and 2FL alone or with assistance of engine 4. At the time of braking, motor generator MG2 performs a regenerative operation and converts the rotational energy of the wheels into electric energy. The obtained electric energy is returned to the battery B <b> 1 via the inverter 30 and the booster unit 10.

  System main relays SR1 and SR2 are provided between booster unit 10 and battery B1, and the high voltage is cut off when the vehicle is not in operation.

  The vehicle 1 further includes a vehicle speed sensor 8 that detects the vehicle speed, an accelerator sensor 9 that is an input unit that receives an acceleration request instruction from the driver and detects the position of an accelerator pedal, a voltage sensor 70 that is attached to the battery B1, And a control device 60 that controls the engine 4, the inverters 20, 30 and the booster unit 10 in accordance with the accelerator opening Acc from the accelerator sensor 9 and the voltage VB from the voltage sensor 70. The voltage sensor 70 detects the voltage VB of the battery B1 and transmits it to the control device 60.

  The vehicle 1 further includes a connecting portion 16 for connecting a plug 104 provided at the end of a charging cable 102 extending from the external power source 100, and a charger 12 that receives AC power from the external power source 100 via the connecting portion 16. And further including. The charger 12 is connected to the battery B1 and supplies DC power for charging to the battery B1.

  Here, control device 60 performs charging shown in FIG. 1 so that battery B1 is charged from an AC voltage applied from the outside of the vehicle based on signal IG from the ignition switch (or ignition key) and charge state SOC of battery B1. The device 12 is controlled.

  That is, when the vehicle is parked and signal IG is off and voltage is applied to connection 16 from the outside, control device 60 determines whether charging is possible based on the state of charge SOC of battery B1, When it is determined that charging is possible, the charger 12 is driven. On the other hand, when it is determined that the battery B1 is almost fully charged and cannot be charged, the control device 60 stops the charger 12 even if voltage is applied to the connection unit 16 from the outside.

  Vehicle 1 further includes an air conditioner 11 that receives electric power from battery B1 or charger 12 and air-conditions the passenger compartment. An air conditioner 11 is connected between the boosting unit 10 and the system main relays SR1 and SR2. The power supply voltage of the air conditioner is supplied from the battery B1 or the charger 12, or is supplied from the booster unit using electric power generated by the power of the engine.

  The air conditioner 11 operates by receiving electric power from the battery B1 while the vehicle is running. On the other hand, when the vehicle 1 is connected to the external power source 100 via the charging cable 102 and preliminary air conditioning is performed before the vehicle starts, the air conditioner 11 receives power from the external power source 100 via the charger 12. Works. Such air conditioning is called pre-air conditioning.

FIG. 2 is a diagram for explaining a configuration for driving an electric load which is an auxiliary machine of the vehicle 1.
Referring to FIG. 2, in addition to the configuration shown in FIG. 1, vehicle 1 further includes DC / DC converter 72, relay box 74, fusible link 76, auxiliary battery 82, and auxiliary battery. And an electric load 78 including a tail lamp, an air conditioner blower, an engine cooling device, a battery cooling device, and the like.

  Control device 60 instructs DC / DC converter 72 of the generated voltage (target value of the output voltage). The DC / DC converter 72 converts the voltage of the battery B1 and outputs it to the electric load 78 and the auxiliary battery 82.

  The auxiliary battery 82 and the electric load 78 are connected to the DC / DC converter 72 by a fusible link 76. A relay box 74 is disposed between the fusible link 76 and the DC / DC converter 72.

  The temperature of the auxiliary battery 82 is given from the sensor 84 toward the control device 60. Moreover, the connection part 16 is connected to AC 100V of commercial power, and the battery B1 can be charged by the charger 12. The connecting portion 16 may be a plug into which a plug is inserted as shown in FIG. 1, or a plug to be inserted into an external power supply outlet as shown in FIG. Plug-in operation information IGP indicating whether or not plug-in charging is being performed is transmitted from the charger 12 to the control device 60.

  FIG. 3 is a transition diagram showing state transition of the target value of the output voltage of DC / DC converter 72 shown in FIG.

  Referring to FIG. 3, in the initial state ST1, the target output voltage of DC / DC converter 72 is, for example, 14V. In the forced output mode ST2 that moves by the transition indicated by the arrow A3 from the initial state, the target output voltage is set to 14 V, for example. In the forced output mode ST2, when the vehicle is set to READY OFF, the shift range is set to the P range (parking range), or the engine water temperature <−10 ° C. is established, the transition indicated by the arrow A5 occurs, and the cryogenic output mode ST3 Transition to. In this mode, startability at extremely low temperatures is improved. At this time, the target output voltage of the DC / DC converter is set to 10.5V, for example. When READYON, the shift range is other than the parking range, and the engine is in a complete explosion state, a transition from the cryogenic output mode ST3 to the forced output mode ST2 occurs as indicated by an arrow A4.

  In the forced output mode ST2, when the electric load is off, not left for a long time (after engine startup), and the engine water temperature is + 10 ° C. or higher and + 50 ° C. or lower is satisfied, the fuel efficiency improvement mode ST4 as shown by an arrow A6. Transition to. In the fuel efficiency improvement mode, the target output voltage of the DC / DC converter 72 is set to 13.5V, for example.

  As indicated by an arrow A7, when the electric load is in an on state or left for a long time after the engine is started, or when the engine water temperature is lower than + 10 ° C. or higher than + 50 ° C., the forced output mode ST2 is changed to the normal control mode ST5 Transition. In the normal control mode, the target output voltage of the DC / DC converter 72 is set using a temperature correlation map between 13.5 and 15.0 V, for example. This changes the target output voltage of the DC / DC converter 72 according to the temperature of the auxiliary battery, and the correspondence between the battery temperature and the target output voltage is determined by a predetermined temperature correlation map.

  As indicated by arrow A8, when the electric load is on or the condition that the engine water temperature is lower than + 10 ° C. or higher than + 50 ° C. is satisfied, a transition from the fuel efficiency improvement mode ST4 to the normal control mode ST5 occurs. As indicated by an arrow A9, when the condition that the electric load is off and the engine water temperature is + 10 ° C. or higher and + 50 ° C. or lower is established, a transition from the normal control mode ST5 to the fuel consumption improvement mode ST4 occurs.

The above is the transition that occurs during traveling.
Next, the state transition when performing plug-in charging will be described. As shown by arrow A2, when plug-in operation information IGP is given to controller 60 from charger 12 in FIG. 2, transition from initial state ST1 to plug-in charge mode ST6 is performed. This includes not only when the battery B1 is being charged, but also includes a pre-air conditioning mode in which power is supplied from the commercial power supply to the air conditioner 11 of FIG.

  As indicated by arrow A1, when the transmission of plug-in operation information IGP from charger 12 is stopped, a transition from plug-in charge mode ST6 to initial state ST1 occurs.

  Here, when plug-in charging is performed, the auxiliary battery 82 has some points to be noted as compared with a conventional hybrid vehicle that does not perform plug-in charging.

  First, the life of the auxiliary battery is shortened. When the plug-in charging function is activated, the vehicle stop system, for example, a specific ECU that performs control for charging the battery B1 is activated during a period in which the user is not in the vehicle, in addition to a period in which the user is in the vehicle. When the operation frequency of the electronic vehicle system increases, there is a concern that the charge / discharge frequency of the auxiliary battery increases and the life of the auxiliary battery decreases. The reason is as follows. During the period when the plug-in charging function is activated, it is necessary to start the 12V system, and since the DC / DC converter 72 is activated, the charging / discharging current flows into the auxiliary battery and the charging / discharging frequency increases. Because it does. In order to reduce the frequency of charging / discharging the auxiliary battery, the auxiliary battery charging voltage output from the DC / DC converter 72 is controlled, and when not required, the charging voltage is balanced so that the auxiliary battery is not charged. Need to weave control.

  Second, there is a concern about overcharging of the auxiliary battery. When the plug-in charging function is activated, the charge / discharge frequency of the auxiliary battery is increased, and there is a concern that the auxiliary battery may fail early (cell short). When the auxiliary battery fails (cell short-circuit), the auxiliary battery 82 is excessively charged by the DC / DC converter 72, so that the battery life is further reduced.

  If the auxiliary battery 82 is out of order (cell short) while the plug-in charging function is operating, the auxiliary battery will be overcharged if the output of the DC / DC converter 72 is kept constant. . In order to suppress overcharge of the auxiliary battery, it is necessary to incorporate a control for controlling the charging voltage of the auxiliary battery 82 and balancing the charging voltage so as not to charge the auxiliary battery when unnecessary.

  Thirdly, there is a concern about the problem of the auxiliary battery running out. If the state in which the vehicle is left without starting is long or the state of insufficient charging due to a short start time (short trip) continues, the remaining capacity of the auxiliary battery becomes insufficient. Various ECUs such as the vehicle control device 60 are supplied with the power supply voltage from the auxiliary battery, so that the vehicle cannot be started when the remaining capacity of the auxiliary battery decreases. Therefore, in order to recover the decrease in the remaining capacity of the auxiliary battery 82, the charging voltage of the auxiliary battery 82 is controlled even during the period in which the plug-in charging function is activated, and control for recovering the remaining capacity of the auxiliary battery is performed. It is necessary to weave.

  Therefore, by performing the control described below, it is possible to prevent the auxiliary battery from being deteriorated and the life of the auxiliary battery being reduced.

  FIG. 4 is a flowchart for explaining control of the DC / DC converter at the time of plug-in charging performed by the control device 60.

  Referring to FIG. 4, when the process is started, control device 60 determines whether or not there is an instruction to start plug-in charging in step S1. For example, whether or not there is an instruction to start plug-in charging is determined based on whether or not the plug 104 is connected to the connection unit 16 in FIG. If it is determined in step S1 that there is an instruction to start plug-in charging, the process proceeds to step S2. On the other hand, if it is determined in step S1 that there is no instruction to start plug-in charging, the process proceeds to step S11 and the process ends.

  In step S <b> 2, the state of the auxiliary battery 82 is detected by the sensor 84. The sensor 84 includes, for example, a temperature sensor, a voltage sensor, and a current sensor. These current, voltage and temperature are detected as the state of the battery.

  Subsequently, in step S3, in order to recover the remaining capacity of the auxiliary battery 82, forced charging is performed at a fixed voltage for a predetermined time. Subsequently, in step S4, a process of detecting a voltage drop of the auxiliary battery is executed. This voltage drop detection process will be described in more detail later.

  In step S5, it is determined whether or not a voltage drop of auxiliary battery 82 has been detected as a result of the voltage drop detection process. For example, when a failure such as a cell short-circuit occurs, a voltage drop is detected. If a voltage drop is detected in step S5, voltage setting for suppressing overcharge is executed in step S6. If no voltage drop is detected in step S5 or if the voltage setting for suppressing overcharge is completed in step S6, the auxiliary charging process is executed in step S7. Further, in step S8, it is determined whether or not auxiliary battery 82 is fully charged. If the battery is not fully charged in step S8, the process returns to step S7 as long as time permits, and the auxiliary charging is continued. On the other hand, when it is detected that the battery is fully charged in step S8, the process proceeds to step S9, and the setting of the target output voltage of the DC / DC converter 72 for maintaining the full charge is executed.

  Subsequently, in step S10, it is determined whether or not a charging end condition is satisfied. The charge termination condition is determined, for example, when a predetermined charging time has elapsed. The charge termination condition is also satisfied when the plug is forcibly removed from the external power source. If the charge termination condition is not satisfied, the process returns to step S4, and the cycle of auxiliary charge and full charge maintenance is repeated from the voltage drop detection process. On the other hand, if the charge termination condition is satisfied in step S10, the process proceeds to step S11, and the process is terminated.

  FIG. 5 is an operation waveform diagram for explaining an example of operation when processing is executed according to the flowchart of FIG.

  Referring to FIG. 5, waveforms W1 to W7 are shown in order from the top. A waveform W1 indicates the output voltage of the DC / DC converter 72 (voltage between the relay box 74 and the fusible link 76 in FIG. 2) detected by the control device 60. A waveform W2 represents a power generation instruction voltage (a target output voltage of the DC / DC converter 72). A waveform W3 indicates on / off of the plug-in charging operation. This is switched on / off depending on whether, for example, the plug 104 is connected to the connection portion 16 or not. Waveform W4 shows the starting state of the control device (power management ECU). Waveform W5 represents a period during which the auxiliary battery is fully charged.

  Waveform W6 shows a state that is detected when a battery voltage drop occurs. A waveform W7 indicates an interval at which the voltage drop detection process is executed. The processing contents to be executed in order are shown below the waveform W7.

  The waveform operation will be described below in order. First, at time t1, the waveform indicating the plug-in operating state is activated when the vehicle is connected to the external power source. Subsequently, in response to this, the control device 60 is activated at time t2 as shown by the waveform W4.

  Subsequently, at time t <b> 3, control device 60 performs initial charging for DC / DC converter 72. This initial charging is effective in recovering the remaining capacity of the auxiliary battery. At this time, the value set as the target output voltage of the DC / DC converter 72 is a fixed value and is forcibly set. The set voltage VC1 between times t3 and t4 is, for example, a fixed value of 14.0V.

  Subsequently, a voltage drop detection process is executed from time t4 to t8. The voltage drop detection process is performed over a length of 10 minutes, for example. The target output voltage gradually decreases from VC1 to VC3.

  Voltage VC3 is a voltage lower than the normal power supply voltage of the electric load connected to the auxiliary battery. By providing such a voltage to the auxiliary battery, a large voltage difference appears between the case where a short circuit between cells occurs and the case where it does not. For example, as shown at point P2, when the detected voltage indicated by the waveform W1 falls below the voltage VC3, this history is retained. Then, when such a decrease is detected again in the voltage decrease detection process repeated after time t17, the occurrence of an abnormality in the auxiliary battery is determined. The target voltage set at times t6 to t8 is, for example, 11.5V.

  Such a low voltage is not preferable because it may affect the operation of the electric load during traveling. Therefore, such a low voltage is set as the target voltage in order to diagnose the auxiliary battery only during plug-in charging in which only a small part of the electric load is activated.

  Subsequently, from time t8 to t13, supplementary charging is performed as processing contents. In the auxiliary charging, for example, an auxiliary charging voltage corrected in accordance with the temperature of the auxiliary battery between 13.5 and 15.0 V is applied. It is determined that the auxiliary battery has reached full charge in response to the detection voltage indicated by waveform W1 exceeding a predetermined threshold at point P3.

  Then, as shown in waveform W5, processing for maintaining full charge is performed after time t3. At times t14 to t17, a voltage slightly lower than the auxiliary charging voltage, for example, 12.5 to 13.5 V is set as the target voltage. Thus, the life of the auxiliary battery can be extended by lowering the voltage below the auxiliary charging voltage and balancing the voltages so that neither charging nor discharging occurs in the auxiliary battery.

  As described above, basically, the forcible setting process from time t3 to t4 is first executed, the voltage drop detection process from time t4 to t8 is subsequently executed, and the auxiliary charging process from time t8 to t13 is further executed. Finally, the full charge maintaining process at times t13 to t17 may be executed. However, in order to increase the detection accuracy of abnormalities such as cell shorts in the auxiliary battery detected in the voltage drop detection process and avoid erroneous detection, the voltage drop detection process is repeatedly performed as shown at times t17 to t21. It is even better to determine the occurrence of a failure in the auxiliary battery when a voltage drop in the auxiliary battery is detected. In such a case, supplementary charging and full charge maintenance processing are continuously performed. In the waveform shown in FIG. 5, the charging time ends at time t24, and the output target set value of the DC / DC converter is zero.

FIG. 6 is a waveform diagram for explaining details of the voltage drop detection process in the waveform of FIG.
Waveforms W1-W4 in FIG. 6 are similar to those in FIG. Waveform W11 shows the value of the counter that measures the elapsed time after plug-in ON (after the power management ECU is activated). A waveform W12 indicates a flag indicating that initial charging is being performed.

  A waveform W13 shows the value of the counter indicating the passage of the processing time of the battery voltage drop detection process. A waveform W14 indicates a flag indicating that the battery voltage drop is being detected. A waveform W15 shows the value of the counter indicating the passage of time since the battery voltage drop was detected. A waveform W16 indicates a flag indicating that a battery voltage drop is detected.

  As the control device 60 in FIGS. 1 and 2, an ECU (Electronic Control Unit) incorporating a computer can be used. As is well known, the built-in computer operates at a predetermined clock frequency and has a function of measuring time using a counter. Waveforms W11, W13, and W15 show how the count value of the counter is counted up to the target time and how it is reset at a certain timing after the target time is counted up.

  At time t2, the counter indicating the elapsed time after plug-in on shown in waveform W11 starts counting simultaneously with the rise of the initial charging flag shown in waveform W12. For example, when the counter finishes counting after 120 seconds, the initial charging flag changes from the on state to the off state.

  In response to this, the battery voltage drop detection flag shown in waveform W14 changes from the OFF state to the ON state, and the elapsed time counter of the battery voltage drop detection process starts counting up as shown in waveform W13. For example, this count time is 600 seconds.

  At time t8, when 600 seconds have elapsed, the flag shown in waveform W14 changes from the on state to the off state. During this time, it is assumed that the voltage detected by control device 60 between times t6 and t7 reaches a predetermined threshold value as shown by the line branched downward in waveform W1. In response to this, the counter indicated by the waveform W15 starts counting up. For example, when 10 seconds have elapsed, the battery voltage drop flag indicated by the waveform W16 changes from the OFF state to the ON state. At time t8, the waveforms W14, W15, and W16 are turned off or returned to 0 in response to completion of the count up of the counter shown in the waveform W13.

FIG. 7 is an operation waveform diagram for explaining details during the full charge detection process.
Waveforms W1-W4 and W11, W12 in FIG. 7 are the same as in FIG. 6, and therefore description thereof will not be repeated. In response to the end of the voltage drop detection process measured by the counter indicated by the waveform W13 in FIG. 6, the auxiliary charging flag changes from the OFF state to the ON state as indicated by the waveform W22 at time t8 in FIG. As shown in the waveform W21, the auxiliary charge elapsed time counter starts counting up. The count-up time of this counter is 3600 seconds, for example.

  Between times t11 and t12, when the detected voltage indicated by waveform W1 exceeds the threshold value, the battery full charge elapsed time counter starts counting up. The threshold is set to a value obtained by subtracting a predetermined value from the power generation instruction voltage (target output voltage value) of the DC / DC converter 72, for example. The count-up time of the battery full charge elapsed counter is, for example, 300 seconds.

  When this count-up is completed, the battery full charge completion flag changes from the off state to the on state at time t13. When the count up of the counter shown in waveform W21 is completed, the auxiliary charge flag changes from the on state to the off state as shown in waveform W22, the counter shown in waveform W23 is reset, and the battery shown in waveform W24 is reset. The full charge completion flag is also reset from the on state to the off state.

  As described above, in the present embodiment, control device 60 periodically changes the target output voltage value of DC / DC converter 72 during the plug-in charging period. As a result, recovery of the remaining capacity of the auxiliary battery, detection of failure, and suppression of charging / discharging during full charge maintenance are achieved. Therefore, when plug-in charging is performed, it is possible to avoid significantly shortening the life of the auxiliary battery.

  Even when plug-in charging is not performed, control for changing the target output voltage value of the DC / DC converter 72 periodically is performed in the same manner when pre-air conditioning is performed by connecting a vehicle to an external power source. By doing so, recovery of the remaining capacity of the auxiliary battery, detection of failure, and suppression of charge / discharge during full charge maintenance can be achieved, and similar effects can be expected.

[Modification]
FIG. 8 is a diagram showing a modification of the configuration shown in FIG.

  Referring to FIG. 8, in this modification, in addition to the configuration shown in FIG. 2, a solar cell 204 and a DC / DC converter 202 are further provided. In this modification, a fail-safe function is added. This enables the vehicle to be activated independently by the solar battery 204 when the auxiliary battery breaks down during plug-in charging.

  Even when a failure occurs in the auxiliary battery 82, the voltage of the solar battery 204 is supplied as the power supply voltage of the control device 60 via the DC / DC converter 202, and the vehicle startup process can be executed. . Further, the vehicle can be started even if the high voltage battery B1 is divided and 12V is supplied as the power supply voltage of the control device 60 via the DC / DC converter 202. As a result, traveling for a certain period, for example, retreat traveling such as when transporting to a dealer, is possible.

  Furthermore, during plug-in charging, when a failure of the auxiliary battery is detected in the voltage drop detection process, it is further preferable to notify the user using the remote service function. During plug-in charging, the driver is often away from the vehicle. For example, the vehicle key owned by the driver or an information terminal at home is automatically notified of the battery failure. By providing a function for notifying the user when the auxiliary battery is faulty, it is possible to announce the quick supply of the auxiliary battery.

  Finally, referring to FIGS. 1 and 2 again, the present embodiment will be summarized. Vehicle 1 of the present embodiment converts battery B1, which is a power storage device configured to be rechargeable from the outside, main load devices (inverters 20, 30, etc.) that receive power supply from battery B1, and converts the voltage of battery B1. A DC / DC converter 72, an auxiliary battery 82 to which a voltage converted by the DC / DC converter 72 is supplied, and an electric load 78 that is supplied with a power supply voltage from the DC / DC converter 72 and the auxiliary battery 82; A sensor 84 for detecting the state of the auxiliary battery 82 and a control device 60 for controlling the DC / DC converter 72 are provided. As shown in FIGS. 5 to 7, control device 60 performs DC in the auxiliary charging period when the vehicle and the external power source are electrically coupled to battery B <b> 1 so that charging can be performed from the outside. When the output target voltage of DC / DC converter 72 is set to the auxiliary charging voltage (VC1) to perform auxiliary charging of auxiliary battery 82 and abnormality is detected in the state of auxiliary battery 82 by sensor 84, auxiliary charging is performed. In the period, a voltage (for example, 11.5 V) different from the auxiliary charging voltage (VC1 that is variably set) is set as the output target voltage of the DC / DC converter 72.

  Preferably, the control device 60 sets the fixed voltage regardless of the state of the auxiliary battery 82 detected by the sensor 84 at an initial time P1 before the auxiliary charging period and when the battery B1 is charged from the outside. (Fixed VC1) is set as the output target voltage of the DC / DC converter 72.

  More preferably, sensor 84 includes a voltage sensor that detects the voltage of auxiliary battery 82. The control device 60 sets a voltage (VC3) lower than the power supply voltage during the normal operation of the electric load 78 at the time point P2 after the initial time P1 and before the auxiliary charging period as the output target voltage of the DC / DC converter 72. Then, it is determined whether or not the state of the auxiliary battery 82 is abnormal based on the degree of decrease in the voltage of the auxiliary battery 82.

  Preferably, an air conditioner 11 that receives power supply from the battery B1 and a heater are further provided. The air conditioner 11, the heater, and the like are configured to be able to perform preliminary air conditioning before starting the vehicle by receiving power from the external power source when the vehicle and the external power source are electrically coupled. Control device 60 sets the target voltage of DC / DC converter 72 to a voltage lower than the auxiliary charging voltage when the voltage drop of auxiliary battery 82 is detected by sensor 84 during the preliminary air conditioning.

  Preferably, control device 60 forcibly sets the output target voltage of DC / DC converter 72 to a fixed value when charging battery B1 from the outside, and electric power A second period in which a voltage (VC3) lower than a power supply voltage (for example, 12 to 14 V) during normal operation of the load 78 is set as an output target voltage of the DC / DC converter 72 and an abnormality of the auxiliary battery 82 is determined ( Time t6 to t8), auxiliary charging period (time t8 to t12), and voltage (VC2) lower than the auxiliary charging voltage after elapse of the auxiliary charging period is set as the output target voltage of the DC / DC converter 72, and the auxiliary battery A full charge maintenance period (time t14 to t17) for maintaining 82 full charge is provided in order.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a block diagram showing a configuration of a vehicle 1 according to an embodiment of the present invention. 2 is a diagram for explaining a configuration for driving an electrical load that is an auxiliary machine of the vehicle 1; FIG. FIG. 3 is a transition diagram illustrating a state transition of a target value of an output voltage of the DC / DC converter 72 illustrated in FIG. 2. 5 is a flowchart for explaining control of a DC / DC converter during plug-in charging performed by control device 60. FIG. 5 is an operation waveform diagram for explaining an example of an operation when processing is executed according to the flowchart of FIG. 4. FIG. 6 is a waveform diagram for explaining details of a voltage drop detection process in the waveform of FIG. 5. It is an operation | movement waveform diagram for demonstrating the detail at the time of a full charge detection process. FIG. 3 is a diagram showing a modified example of the configuration shown in FIG. 2.

Explanation of symbols

  1 vehicle, 2FR, 2FL front wheel, 2RR, 2RL rear wheel, 4 engine, 5, 6 gear, 8 vehicle speed sensor, 9 accelerator sensor, 10 boosting unit, 11 air conditioner, 12 charger, 16 connection part, 20, 30 inverter, 60 control device, 70 voltage sensor, 72, 202 DC / DC converter, 74 relay box, 76 fusible link, 78 electric load, 82 auxiliary battery, 84 sensor, 100 external power supply, 102 charging cable, 104 plug, 204 sun Battery, B1 battery, MG1, MG2 Motor generator, PG planetary gear, SR1, SR2 System main relay.

Claims (4)

A power storage device configured to be externally chargeable;
A main load device that receives power from the power storage device;
A voltage converter for converting the voltage of the power storage device;
An auxiliary battery supplied with the voltage converted by the voltage converter;
And an electrical load Keru receive a supply of said voltage converter and power supply voltage from the auxiliary battery,
A sensor for detecting the state of the auxiliary battery;
A control device for controlling the voltage converter,
The sensor is
A voltage sensor for detecting the voltage of the auxiliary battery,
When the vehicle and an external power source are electrically coupled so that the power storage device can be charged from the outside, the control device is configured to perform an initial charge on the power storage device from the outside. the fixed voltage regardless of the state of the auxiliary battery set the output target voltage of the voltage converter, the output target voltage of the voltage converter in the auxiliary charge period after the time of the initial detected by the sensor Is set to an auxiliary charging voltage to perform auxiliary charging of the auxiliary battery, and a voltage lower than the power supply voltage during normal operation of the electric load at a time after the initial time and before the auxiliary charging period is A vehicle that is set to the output target voltage of a voltage converter and determines whether or not the state of the auxiliary battery is abnormal based on the degree of decrease in the voltage of the auxiliary battery . When an abnormality is detected in the state of the auxiliary battery by the sensor , the control device outputs a voltage for suppressing overcharging of the auxiliary battery during the auxiliary charging period to the output target of the voltage converter. The vehicle according to claim 1, wherein the vehicle is set to a voltage . Wherein the control device, when charging from the outside to the power storage device, a first time period to be set to force the fixed value the output target voltage of the voltage converter, the power supply during normal operation of the electric load a second period determining an abnormality of the auxiliary battery by setting a lower voltage to the output target voltage of the voltage converter from the voltage, and the supplemental charging period, the auxiliary charging voltage after the auxiliary charge period It provided sequentially and fully charged sustain period for maintaining the full charge of the auxiliary battery by setting a lower voltage to the output target voltage of the voltage converter from the vehicle according to claim 1. 4. The control device according to claim 3, wherein the control device repeatedly provides the second period, the auxiliary charging period, and the full charge maintaining period in order until a charge termination condition is satisfied after the first period has elapsed. vehicle.

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