Vehicle

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. Disclose an electric vehicle that charges an auxiliary power storage device.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2007-209168</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2005-229665</text></patcit>

<p> In recent years, even in hybrid vehicles, it has been studied to configure the battery so that it can be charged from the outside. However, it becomes necessary to keep the vehicle system running during the charging time, and as a result, the time required for charging and discharging the auxiliary battery increases, and there is a concern that the auxiliary battery may deteriorate or be overcharged. To.</p><p> An object of the present invention is to provide a vehicle capable of reducing the possibility of deterioration and overcharging of an auxiliary battery when charging from the outside of the vehicle.</p>

<p> In summary, the present invention is a vehicle, a power storage device configured to be rechargeable from the outside, a main load device that receives power from the power storage device, a voltage converter that converts the voltage of the power storage device, and voltage conversion. Auxiliary battery to which the voltage converted by the device is supplied, the electric load that receives the power supply voltage from the voltage converter and the auxiliary battery, the sensor that detects the state of the auxiliary battery, and the control of the voltage converter. It is provided with a control device for performing. The control device uses the output target voltage of the voltage converter as the supplementary charging voltage during the supplementary charging period when the vehicle and the external power supply are electrically coupled so that the power storage device can be charged from the outside. If an abnormality is detected in the condition of the auxiliary battery by the sensor after setting and supplementary charging of the auxiliary battery, a voltage different from the supplementary charging voltage is set as the output target voltage of the voltage converter during the supplementary charging period. To do.</p><p> Preferably, the control device converts a fixed voltage to a voltage converter regardless of the state of the auxiliary battery detected by the sensor at the initial stage when the power storage device is externally charged before the supplementary charging period. Set to the output target voltage of.</p><p> 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 electric load as the output target voltage of the voltage converter at a time after the initial time and before the supplementary charging period, and the voltage of the auxiliary battery drops. It is determined whether or not the state of the auxiliary battery is abnormal based on the degree of.</p><p> Preferably, it further includes an air conditioner that receives power from the power storage device. The air conditioner is configured to be capable of performing preliminary air conditioning before the vehicle starts by receiving electric power from the external power source when the vehicle and the external power source are electrically coupled. When the sensor detects a voltage drop in the auxiliary battery during pre-air conditioning, the control device sets the target voltage of the voltage converter to a voltage lower than the supplementary charging voltage.</p><p> Preferably, the control device has a first period in which the output target voltage of the voltage converter is forcibly set to a fixed value when charging the power storage device from the outside, and the power supply voltage during normal operation of the electric load. The voltage converter sets a lower voltage as the output target voltage of the voltage converter to determine the abnormality of the auxiliary battery, the supplementary charging period, and the voltage lower than the supplementary charging voltage after the supplementary charging period elapses. The full charge maintenance period for maintaining the full charge of the auxiliary battery by setting the output target voltage of is set in order.</p>

<p> According to the present invention, when the plug-in is charged from the outside, deterioration of the auxiliary battery can be suppressed and the possibility of overcharging can be reduced.</p>

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the 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. This vehicle 1 is a hybrid vehicle that uses both a motor and an engine to drive wheels.

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

The vehicle 1 further includes a battery B1, a booster unit 10 that boosts the DC power output by the battery B1, and inverters 20 and 30 that transfer DC power between the booster units 10.

The vehicle 1 further includes a motor generator MG1 that receives mechanical power of the engine 4 via a planetary gear PG to generate electric power, and a motor generator MG2 whose rotating shaft is connected to the planetary gear PG. The inverters 20 and 30 are connected to the motor generators MG1 and MG2 to convert AC power and DC power from the booster unit 10.

The planetary gear PG operates as a power split mechanism that is coupled to the engine 4 and the motor generators MG1 and MG2 to distribute power between them.

The 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. The planetary gear PG has first to third rotation shafts. The first rotating shaft is the rotating shaft of the planetary carrier connected to the engine 4. The second rotating shaft is the rotating shaft of the sun gear connected to the motor generator MG1. The third rotating shaft is the rotating shaft of the ring gear connected to the motor generator MG2.

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

A gear 5 is attached to the third rotating shaft, and the gear 5 transmits mechanical power to the differential gear DG by driving the gear 6. The differential gear DG transmits the mechanical power received from the gear 6 to the front wheels 2FR and 2FL, and also 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.

The planetary gear PG determines the rotation of the remaining one rotating shaft according to the rotation of two of the three rotating shafts. Therefore, while operating the engine 4 in the most efficient region, the vehicle speed is controlled by controlling the amount of power generated by the motor generator MG1 and driving the motor generator MG2, thereby realizing an energy-efficient automobile as a whole. There is.

A speed reducer for the rotating shaft of the motor generator MG2 may be further incorporated inside the planetary gear PG.

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

The inverter 30 drives the motor generator MG2. The motor generator MG2 drives the front wheels 2FR and 2FL alone or by assisting the engine 4. During braking, the motor generator MG2 performs regenerative operation to convert the rotational energy of the wheels into electrical energy. The obtained electrical energy is returned to the battery B1 via the inverter 30 and the booster unit 10.

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

The vehicle 1 further includes a vehicle speed sensor 8 for detecting the vehicle speed, an accelerator sensor 9 for detecting the position of the accelerator pedal, which is an input unit for receiving an acceleration request instruction from the driver, and a voltage sensor 70 attached to the battery B1. It includes an engine 4, inverters 20, 30 and a control device 60 that controls 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 has a connection portion 16 for connecting a plug 104 provided at the end of a charging cable 102 extending from the external power supply 100, and a charger 12 that receives AC power from the external power supply 100 via the connection portion 16. And further include. The charger 12 is connected to the battery B1 and supplies DC power for charging to the battery B1.

Here, the control device 60 charges the battery B1 from the AC voltage given from the outside of the vehicle based on the signal IG from the ignition switch (or the ignition key) and the charge state SOC of the battery B1. Control vessel 12.

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

The vehicle 1 further includes an air conditioner 11 that receives power from the battery B1 or the charger 12 to air-condition the passenger compartment. An air conditioner 11 is connected between the booster 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 the 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 by the charging cable 102 and the pre-air conditioning is performed before the vehicle starts, the air conditioner 11 receives power from the external power source 100 via the charger 12. To work. 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. With reference to FIG. 2, in addition to the configuration shown in FIG. 1, vehicle 1 further includes a DC / DC converter 72, a relay box 74, a fusible link 76, an auxiliary battery 82, and an auxiliary battery. It includes a sensor 84 for detecting the state of the electric load 78 and an electric load 78 including a tail lamp, an air conditioner blower, an engine cooling device, a battery cooling device, and the like.

The control device 60 instructs the 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 electrical load 78 are connected to the DC / DC converter 72 by a fusible link 76. A relay box 74 is arranged 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. Further, the connection portion 16 is connected to the AC 100V of the commercial power source, and the battery B1 can be charged by the charger 12. The connection portion 16 may be a plug into which a plug is inserted as shown in FIG. 1, or may be a plug to be inserted into an external power outlet as shown in FIG. From the charger 12, plug-in operation information IGP indicating whether or not plug-in charging is being performed is transmitted to the control device 60.

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

With reference to FIG. 3, the target output voltage of the DC / DC converter 72 in the initial state ST1 is, for example, 14V. Also, in forced output mode ST2, which moves from the initial state by the transition indicated by arrow A3, the target output voltage is also set to, for example, 14V. When the vehicle is READY OFF, the shift range is set to the P range (parking range), or the engine water temperature &lt;-10 ° C is satisfied in the forced output mode ST2, the transition shown by arrow A5 occurs and the extremely low temperature output mode Transition to ST3. In this mode, startability at cryogenic temperatures is improved. At this time, the target output voltage of the DC / DC converter is set to, for example, 10.5V. 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 shown by arrow A4.

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

As shown by arrow A7, when the electric load is on, the engine is left for a long time after starting, or the engine water temperature is less than + 10 ° C or higher than + 50 ° C, the forced output mode ST2 to the normal control mode The state transitions to ST5. In normal control mode, the target output voltage of the DC / DC converter 72 is set, for example, between 13.5 and 15.0V using a temperature correlation map. 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 shown by arrow A8, when the condition that the electric load is on or the engine water temperature is less than + 10 ° C or greater than + 50 ° C is satisfied, the transition from the fuel consumption improvement mode ST4 to the normal control mode ST5 occurs. To do. Further, as shown by arrow A9, when the conditions that the electric load is off, the engine water temperature is + 10 ° C or higher and + 50 ° C or lower are satisfied, the transition from the normal control mode ST5 to the fuel consumption improvement mode ST4 occurs.

The above is the transition that occurs during running. Next, the state transition when the plug-in is charged will be described. As shown by arrow A2, when the plug-in operation information IGP is given to the control device 60 from the charger 12 in FIG. 2, the transition from the initial state ST1 to the plug-in charging mode ST6 is performed. This includes not only when the battery B1 is being charged, but also a pre-air conditioning mode in which power is supplied from a commercial power source to the air conditioner 11 of FIG. 1 via a charger 12 to perform pre-air conditioning.

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

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

The first is to shorten the life of the auxiliary battery. By activating the plug-in charging function, the vehicle stopping system, for example, a specific ECU that controls for charging the battery B1, is activated during the period when the user is not in the vehicle as well as the period when the user is not in the vehicle. When the operating frequency of the electronic vehicle system increases, there is a concern that the charging / discharging frequency of the auxiliary battery increases and the life of the auxiliary battery decreases. The reason is that during the period when the plug-in charging function operates, it is necessary to start the 12V system, and the DC / DC converter 72 operates, so the charge / discharge current flows into the auxiliary battery and the charge / discharge frequency increases. Because it does. In order to reduce the frequency of charging and discharging the auxiliary battery, the charging voltage of the auxiliary battery output by the DC / DC converter 72 is controlled, and the charging voltage is balanced so that the auxiliary battery is not charged when it is not needed. Control needs to be factored in.

Second, there is concern about overcharging of the auxiliary battery. When the plug-in charging function is activated, the frequency of charging and discharging the auxiliary battery increases, and there is a concern that the auxiliary battery may fail (cell short) at an early stage. When the auxiliary battery fails (cell short), the DC / DC converter 72 overcharges the auxiliary battery 82, further reducing the battery life.

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

Thirdly, there is concern about the problem of running out of auxiliary battery. If the vehicle is left unattended for a long time, or if the starting time is short (short trip) and the state of insufficient charge continues, the remaining capacity of the auxiliary battery will be insufficient. Since various ECUs such as the vehicle control device 60 receive the power supply voltage from the auxiliary battery, 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 when the plug-in charging function is activated, and the control for recovering the remaining capacity of the auxiliary battery 82 is performed. Need to weave.

Therefore, by performing the control as described below, deterioration of the auxiliary battery and shortening of the life can be prevented.

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

With reference to FIG. 4, when the process is first started, the control device 60 determines whether or not there is an instruction to start plug-in charging in step S1. For example, in FIG. 1, it is determined whether or not there is an instruction to start plug-in charging depending on whether or not the plug 104 is connected to the connection portion 16. If it is determined in step S1 that there is an instruction to start charging the plug-in, 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 S2, 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 currents, voltages and temperatures are detected as battery status.

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

As a result of the voltage drop detection process in step S5, it is determined whether or not the voltage drop of the auxiliary battery 82 is detected. For example, when a failure such as a cell short occurs, a voltage drop is detected. When a voltage drop is detected in step S5, the voltage setting for suppressing overcharging 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 supplementary charging process is executed in step S7. Further, in step S8, it is determined whether or not the 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 supplementary charging is continued. On the other hand, if it is detected in step S8 that the battery is fully charged, the process proceeds to step S9, and the target output voltage of the DC / DC converter 72 for maintaining the full charge is set.

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

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

With reference to FIG. 5, waveforms W1 to W7 are shown in order from the top. Waveform W1 shows 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 controller 60. The waveform W2 indicates the power generation instruction voltage (target output voltage of the DC / DC converter 72). Waveform W3 indicates on / off of plug-in charging operation. This is switched on / off depending on whether or not the plug 104 is connected to the connection portion 16, for example. Waveform W4 indicates the activation state of the control device (power management ECU). The waveform W5 indicates the period during which the full charge detection of the auxiliary battery is performed.

Waveform W6 indicates the state detected when the battery voltage drops. Waveform W7 indicates the interval at which the voltage drop detection process is executed. And below the waveform W7, the processing contents to be executed in order are shown.

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

Subsequently, at time t3, the control device 60 initially charges the DC / DC converter 72. This initial charge 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 the times t3 and t4 is, for example, a fixed value of 14.0V.

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

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

It should be noted that 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 to the target voltage for diagnosis of the auxiliary battery only during plug-in charging where only a small portion of the electrical load is activated.

Subsequently, at times t8 to t13, supplementary charging is performed as the processing content. In supplementary charging, for example, a supplementary charging voltage adjusted according to the temperature of the auxiliary battery is applied between 13.5 and 15.0V. At point P3, it is determined that the auxiliary battery has reached full charge when the detection voltage indicated by the waveform W1 exceeds a predetermined threshold value.

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

As explained above, basically, the forced setting process at times t3 to t4 is executed first, then the voltage drop detection process at times t4 to t8 is executed, and then the supplementary charging process at times t8 to t13 is executed. Finally, the full charge maintenance process at times t13 to t17 may be executed. However, in order to improve the detection accuracy of abnormalities such as cell shorts of the auxiliary battery detected by the voltage drop detection process and avoid erroneous detection, the voltage drop detection process is repeated as shown at times t17 to t21 to continue the voltage drop detection process. It is even better to confirm the occurrence of the auxiliary battery failure when the voltage drop of the auxiliary battery is detected. In such a case, supplementary charging and full charge maintenance processing are continuously executed. 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 becomes 0.

FIG. 6 is a waveform diagram for explaining the details of the voltage drop detection process in the waveform of FIG. Since the waveforms W1 to W4 in FIG. 6 are the same as those in FIG. 5, the explanation is not repeated. The waveform W11 shows the value of the counter that measures the elapsed time after the plug-in is turned on (after the power management ECU is started). The waveform W12 indicates a flag indicating that the initial charge is in progress.

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

As the control device 60 in FIGS. 1 and 2, an ECU (Electronic Control Unit) having a built-in computer can be used. As is well known, the built-in computer has a function of operating at a predetermined clock frequency and 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 counting up the target time.

At time t2, the counter indicating the elapsed time after the plug-in is turned on, which is shown in the waveform W11, starts counting at the same time when the initial charging flag shown in the waveform W12 rises. For example, when this counter completes counting after 120 seconds, the initial charging flag changes from the on state to the off state.

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

Then, at time t8, when 600 seconds have passed, the flag shown in the waveform W14 changes from the on state to the off state. During this time, it is assumed that the voltage detected by the controller 60 between the times t6 and t7 reaches a predetermined threshold value as shown by the line branched to the lower side of the waveform W1. In response to this, the counter shown in the waveform W15 starts counting up, and for example, when 10 seconds have elapsed, the battery voltage drop flag shown in the waveform W16 changes from the off state to the on state. Then, at time t8, the waveforms W14, W15, and W16 are returned to the off state or 0 according to the 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. Since the waveforms W1 to W4, W11, and W12 in FIG. 7 are the same as those in FIG. 6, the description will not be repeated. At time t8 in FIG. 7, the supplementary charging flag changes from the off state to the on state as shown in the waveform W22, in response to the end of the voltage drop detection process measured by the counter shown in the waveform W13 in FIG. As shown in the waveform W21, the elapsed time counter during supplementary charging starts counting up. The count-up time of this counter is, for example, 3600 seconds.

When the detection voltage shown in the waveform W1 exceeds the threshold value between the times t11 and t12, the battery full charge elapsed time counter starts counting up. The threshold value is set to, for example, a value obtained by subtracting a predetermined value from the power generation instruction voltage (target output voltage value) of the DC / DC converter 72. The count-up time of the battery full charge progress 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 the waveform W21 is completed, the supplementary charge flag changes from the on state to the off state as shown in the waveform W22, and the counter shown in the waveform W23 is reset and the battery shown in the waveform W24. The full charge completion flag is also reset from the on state to the off state.

As described above, in the present embodiment, the control device 60 periodically changes the target output voltage value of the DC / DC converter 72 during the plug-in charging period. As a result, the remaining capacity of the auxiliary battery can be recovered, a failure can be detected, and charging / discharging can be suppressed when the battery is fully charged. Therefore, it is possible to avoid significantly shortening the life of the auxiliary battery when the plug-in is charged.

In addition, even when plug-in charging is not executed, when the vehicle is connected to an external power source to perform pre-air conditioning, the control to periodically change the target output voltage value of the DC / DC converter 72 is similarly performed. By doing so, the remaining capacity of the auxiliary battery can be recovered, a failure can be detected, and charging / discharging can be suppressed when the battery is fully charged, and the same effect can be expected.

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

With reference 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 start independently by the solar cell 204 when the auxiliary battery breaks down during plug-in charging.

Even if the auxiliary battery 82 fails, the voltage of the solar cell 204 is supplied as the power supply voltage of the control device 60 via the DC / DC converter 202, and the vehicle can be started. .. Further, 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, the vehicle can be started. As a result, it is possible to travel for a certain period of time, for example, to evacuate when transporting to a dealer.

Further, it is further preferable to notify the user by using the remote service function when a failure of the auxiliary battery is detected in the voltage drop detection process during the plug-in charging. Since the driver is often away from the vehicle while the plug-in is charging, for example, the vehicle key owned by the driver or the information terminal at home is automatically notified that a battery failure has occurred. By providing a function to notify the user when the auxiliary battery fails, it is possible to announce the quick replenishment of the auxiliary battery.

Finally, the embodiments of the present application are summarized with reference to FIGS. 1 and 2 again. The vehicle 1 of the present embodiment converts the voltage of the battery B1 and the battery B1 which is a power storage device rechargeable from the outside, the main load device (inverters 20, 30, etc.) supplied with power from the battery B1. The DC / DC converter 72, the auxiliary battery 82 to which the voltage converted by the DC / DC converter 72 is supplied, and the electric load 78 to receive the power supply voltage from the DC / DC converter 72 and the auxiliary battery 82. It includes a sensor 84 that detects the state of the auxiliary battery 82 and a control device 60 that controls the DC / DC converter 72. As shown in FIGS. 5 to 7, the control device 60 DCs during the supplementary charging period when the vehicle and the external power supply are electrically coupled so that the battery B1 can be charged from the outside. The output target voltage of the / DC converter 72 is set to the supplementary charging voltage (VC1) to perform supplementary charging of the auxiliary battery 82, and if an abnormality is detected in the condition of the auxiliary battery 82 by the sensor 84, supplementary charging is performed. Set a voltage (for example, 11.5V) different from the supplementary charging voltage (variably set VC1) to the output target voltage of the DC / DC converter 72 during the period.

Preferably, the control device 60 has a fixed voltage regardless of the state of the auxiliary battery 82 detected by the sensor 84 at the initial P1 when the battery B1 is externally charged before the supplementary charging period. Set (fixed VC1) to the output target voltage of the DC / DC converter 72.

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

Preferably, an air conditioner 11 or a heater that receives power from the battery B1 is further provided. The air conditioner 11 and the heater are configured to be capable of performing pre-air conditioning before the vehicle starts by receiving electric power from the external power source when the vehicle and the external power source are electrically coupled. When the sensor 84 detects a voltage drop in the auxiliary battery 82 during pre-air conditioning, the control device 60 sets the target voltage of the DC / DC converter 72 to a voltage lower than the supplementary charging voltage.

Preferably, when the battery B1 is charged from the outside, the control device 60 forcibly sets the output target voltage of the DC / DC converter 72 to a fixed value during the first period (time t3 to t4) and electricity. A second period (for example, 12 to 14 V) lower than the power supply voltage (for example, 12 to 14 V) during normal operation of the load 78 is set as the output target voltage of the DC / DC converter 72 to determine an abnormality of the auxiliary battery 82. Auxiliary battery by setting the time t6 to t8), the supplementary charging period (time t8 to t12), and the voltage (VC2) lower than the supplementary charging voltage after the supplementary charging period has elapsed as the output target voltage of the DC / DC converter 72. A full charge maintenance period (time t14 to t17) for maintaining 82 full charges is provided in order.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

<figref num="1">It is a block diagram which shows the structure of the vehicle 1 which concerns on embodiment of this invention.</figref><figref num="2">It is a figure for demonstrating the configuration which drives an electric load which is an auxiliary machine of a vehicle 1.</figref><figref num="3">It is a transition diagram showing the state transition of the target value of the output voltage of the DC / DC converter 72 shown in FIG.</figref><figref num="4">It is a flowchart for demonstrating the control of a DC / DC converter at the time of plug-in charging executed by a control device 60.</figref><figref num="5">It is operation waveform diagram for demonstrating an example of operation when processing is executed according to the flowchart of FIG.</figref><figref num="6">It is a waveform diagram for demonstrating the detail of the voltage drop detection processing in the waveform of FIG.</figref><figref num="7">It is an operation waveform figure for demonstrating the detail at the time of a full charge detection process.</figref><figref num="8">It is a figure which showed the modification of the structure shown in FIG.</figref>

Code description

1 vehicle, 2FR, 2FL front wheel, 2RR, 2RL rear wheel, 4 engine, 5,6 gear, 8 vehicle speed sensor, 9 accelerator sensor, 10 booster unit, 11 air conditioner, 12 charger, 16 connection part, 20,30 inverter, 60 Controller, 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 Solar Battery, B1 battery, MG1, MG2 motor generator, PG planetary gear, SR1, SR2 system main relay.