JP2009089523A - Charge controller of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle the situation of which can be comprehended easily by a driver by simplifying a warning display while reducing power consumption. <P>SOLUTION: The electric vehicle which can run by a motor 2 being driven with electric power supplied from a battery 5 comprises a battery voltage detection means 24 for detecting the voltage of the battery 5, a difference calculating means 31 for calculating a voltage difference (V_diff) from a battery voltage (V_bat) detected by the battery voltage detection means and a preset target voltage (V_trg), and a control means 30 for increasing/decreasing the output of a charger 9 according to the voltage difference (V_diff) when the battery 5 is charged by means of the charger 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to charging control for an electric vehicle that can be driven by a motor driven by electric power supplied from a battery.

  An electric vehicle has a motor as a drive source and a battery as a power supply unit mounted on the vehicle body, and is driven by driving the motor with electric power supplied from the battery. In electric vehicles, the battery performance and capacity will affect the mileage, so normally multiple rechargeable batteries are installed as a unit so that the battery can be charged by the charger when the battery voltage drops due to discharge. It is configured. In addition, in an electric vehicle, a technology is known in which an air conditioner mounted on a vehicle is operated with a timer or the like during charging so that the passenger compartment is comfortable without taking out electric power from the battery.

Japanese Patent No. 3126773

  When charging the battery of an electric vehicle, if charging speed is given priority, charging is performed with the output of the charger being maximized, but rapid charging or excessive charging leads to an increase in battery temperature. As is well known, the deterioration of the battery becomes more severe as the temperature rises. Therefore, it is conceivable to suppress the output from the charger in order to reduce the charging current in order to keep the battery voltage constant at a predetermined voltage.

  In addition, when operating the air conditioner when charging the battery, it is conceivable that the occupant operates the air conditioner immediately before using the electric vehicle, that is, in the latter half of the battery charging, but in the latter half of the battery charging, the battery voltage is fully charged. It is conceivable that the output from the charger is suppressed.

  However, when a high-voltage load device such as an air conditioner is activated with the output from the charger suppressed, the charging current from the charger flows to the load device, and the charging current to the battery decreases. . For this reason, the charging current to the battery is reduced and the charging time is lengthened even though the output (capacity) of the charger has a margin. In addition, when the power used by a load device such as an air conditioner is large, the battery power is used and the battery is discharged even though it is being charged.

  An object of the present invention is to provide a charging control device for an electric vehicle that can prevent an extremely long charging time or discharge from the battery even when a load device is activated during charging of the battery.

  To achieve the above object, a first aspect of the present invention is a charging control device for an electric vehicle that can be driven by a motor driven by electric power supplied from a battery, and a charger that is connected to the battery and supplies current to the battery. Battery voltage detection means for detecting the voltage of the battery, difference calculation means for calculating a voltage difference from the battery voltage detected by the battery voltage detection means and a preset target voltage, and difference calculation at the time of charging by the charger And control means for controlling the output of the charger to increase or decrease in accordance with the voltage difference calculated by the means.

  According to a second aspect of the present invention, in the charging control device for an electric vehicle according to the first aspect, the control means increases the output from the charger as the difference between the target voltage and the battery voltage increases, so that the target voltage and the battery voltage are increased. Control is performed such that the output from the charger decreases as the difference decreases.

  According to the present invention, the voltage difference is calculated by the difference calculation means from the battery voltage detected by the battery voltage detection means and the preset target voltage, and the charger outputs according to the voltage difference when charging by the charger. Therefore, even if the load device operates during charging and the battery voltage fluctuates during charging, the output from the charger will change in the same way. Can be prevented. Also, the output from the charger increases as the voltage difference between the target voltage calculated by the difference calculation means and the battery voltage increases, and the output from the charger decreases as the voltage difference between the target voltage and the battery voltage decreases. Therefore, if the load device is activated during charging and the battery voltage drops, the output from the charger is increased, so the charger's ability can be fully exploited and the charging time is extremely long. Or discharging from the battery can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, an electric vehicle denoted by reference numeral 1 travels by rotating a motor 2 and rotating a wheel 3 by electric power supplied from a battery 5 serving as a power source. The battery 5 is disposed below the seat 4 provided in the passenger compartment 20 of the electric vehicle 1. The battery 5 includes a plurality of cells as one module, and is configured as a battery pack including a plurality of these modules. The battery 5 is housed in a unit housing portion 8 composed of a floor panel 6 constituting the vehicle body and a shielding plate 7 provided below the floor panel 6.

  The electric vehicle 1 includes a charger 9 that supplies current to the battery 5, a battery control unit 10, a cooling unit 15 that cools the battery 5, and a control unit 30 that controls the cooling unit 15 and the charger 9. .

  The cooling means 15 includes a blower fan 14 and a compressor 18 arranged in the outside air introduction path 13, and a heat exchanger 17 arranged in the outside air introduction path 13 by driving the compressor 18 with a blown airflow that is a cooling airflow indicated by a symbol S. The cooling air is circulated between the air conditioner unit 150 to cool the outside air and generate cooling air, and the entire cooling airflow supplied from the air conditioner unit 150 to the unit housing 8 through the duct 16 is discharged outside the vehicle. The exhaust fan 11 is provided.

  The air conditioner unit 150 includes an indoor cooling outlet 15 a that introduces the cooling airflow S into the vehicle interior 20 and a battery cooling outlet 15 b that guides the cooling airflow to the unit housing portion 8, and both are configured to be switched by a damper 19. Has been.

  An introduction port 8a to which a duct 16 is connected is formed on the front side of the unit housing portion 8, and a discharge fan 11 is mounted on a discharge port formed on the rear side 8b. The discharge fan 11 is for sucking air into the unit storage portion 8, and is configured such that the air in the unit storage portion 8 is discharged when the fan rotates.

  The battery 5 in the unit housing portion 8 is configured to be cooled by a cooling airflow S guided and introduced through a duct 16. In this embodiment, the duct 16 is disposed on the floor 6 on the passenger seat 4A side.

  The charger 9 is connected to the battery 5 and the control means 30 with a signal line and a charging cable (not shown). The charger 9 includes a connector 12 connected to an external power source (not shown), and is configured to output electric power supplied from the external power source to the battery 5 via the connector 12. The charger 9 is configured to output the charging current (I_rq) and charging voltage information as its output to the control means, and its output is controlled by the current command value transmitted from the control means 30. It is configured as follows.

  The battery control unit 10 controls the state of charge and temperature of the battery 5, and as shown in FIG. 2, the voltage sensor 24 serving as battery voltage detection means for detecting the voltage of the battery 5 and the current value of the battery 5 are set. A current sensor 25 serving as a battery current detecting means for detecting is connected to a temperature sensor (not shown) for detecting the temperature of the battery 5, and configured to output the remaining battery level and charging timing information to the control means 30. .

  The control means 30 includes a charger 9, a battery control unit 10, a compressor 18, a blower drive motor 21 that drives the blower fan 14, a damper drive unit 22 that drives the damper 19 to switch the outlet of the cooling airflow, and an exhaust fan A discharge drive motor 23 for driving the motor 11 is connected, and the operation of each drive unit is controlled by transmitting an operation command to each drive unit. In the present embodiment, the compressor 18, the blower driving motor 21, and the damper driving unit 22 are load devices, and among them, the compressor 18 is a high-voltage load device.

  A target voltage (V_trg) is preset in the control means 30 and a difference calculating means for calculating a voltage difference (V_diff) from the battery voltage (V_bat) detected by the voltage sensor 24 and the target voltage (V_trg). 31 and a correction value calculating means 32 for calculating a correction value (I_adj) for increasing / decreasing the output of the charger 9 according to the voltage difference (V_diff) calculated by the difference calculating means 31 during charging by the charger 9, A function of controlling the output of the charger 9 to increase or decrease according to the voltage difference (V_diff) is provided.

  The target voltage (V_trg) is mapped and set so as to change according to the charging current (I_rq), and is selected according to the charging current (I_rq). The difference calculation means 31 is configured by a preset mathematical formula.

  The correction value calculation means 32 increases the output from the charger 9 as the voltage difference (V_diff) between the target voltage (V_trg) and the battery voltage (V_bat) increases, and the voltage between the target voltage (V_trg) and the battery voltage (V_bat). It is set so that the output from the charger 9 decreases as the difference (V_diff) decreases.

  The contents of the charging control by the configuration will be described with reference to the flowchart shown in FIG. Here, it is assumed that the main switch is already on. In step A1, the control means 30 determines whether or not the vehicle is being charged. For example, when the socket 12 is connected to a power source, the control means 30 determines that charging is in progress and proceeds to step A2.

  In step A2, the target voltage (V_trg) is set from the charging current (I_rq), and the process proceeds to step A3 to calculate the voltage difference (V_diff) from the battery voltage (V_bat) and the target voltage (V_trg) using the difference calculation means 31. Calculate and proceed to step A4.

  In step A4, a correction value (I_adj) is obtained from the voltage difference (V_diff) by the correction value calculation means 32, and the process proceeds to step A5 where the correction value (I_adj) is added to the charging current (I_rq) to obtain the current command value as a charger 9 to send. The charger 9 increases or decreases the output to the battery 5 according to the current command value.

  Here, the correction value (I_adj) increases the output from the charger 9 as the voltage difference (V_diff) between the target voltage (V_trg) calculated by the difference calculation means 61 and the battery voltage (V_bat) increases, and the target voltage ( The output from the charger 9 is set to decrease as the voltage difference (V_diff) between V_trg) and the battery voltage (V_bat) decreases.

  FIG. 4 shows changes in the battery current, the battery voltage, and the charger output when the charging control of the present invention is performed and not performed. In FIG. 4, when charging is performed, the output from the charger 9 is output at its maximum performance, so the battery voltage rises. When the battery voltage reaches a predetermined value as indicated by P1 in FIG. 4, the output of the charger 9 is reduced as indicated by P2 in FIG. 4 in order to maintain the voltage. At this time, for example, if the load device such as the compressor 18 is not operated, the battery voltage is kept constant even if the output of the charger 9 is reduced. However, when the load device is operated, as indicated by P3 in FIG. As the battery current decreases, the battery voltage also decreases as indicated by P4 in FIG. Further, when the power consumption is larger than the power supplied from the charger 9 due to the operation of the load device, the shortage will be used from the battery 5 as indicated by P3 even during charging.

  On the other hand, when the charge control of the present application is performed, when the load device operates during charging and the battery voltage (V_bat) decreases, the voltage difference (V_diff) from the target voltage (V_trg) increases. Therefore, the control means 30 controls so that the output from the charger 9 becomes large. For this reason, since the electric power supplied to the battery 5 becomes large, the battery voltage is increased as indicated by P4. In addition, the load device operates during charging, and when the load is due to temporary driving such as the damper drive unit 22 or when the power consumption is small and the amount of decrease in the battery voltage (V_bat) is small, Since the voltage difference (V_diff) with respect to the target voltage (V_trg) becomes small, the control means 30 controls to suppress the output from the charger 9.

  As described above, according to the charging control device of the present invention, since the output of the charger 9 is controlled to increase / decrease according to the voltage difference (V_diff) at the time of charging by the charger 9, the load device is controlled during charging. Even if the battery voltage (V_bat) is changed due to the operation, the output from the charger 9 changes in the same manner, so that it is possible to prevent an extremely long charging time and a discharge from the battery 5.

  In particular, as the voltage difference (V_diff) between the target voltage (V_trg) and the battery voltage (V_bat) increases, the output from the charger 9 increases, so the battery voltage drops when the load device is activated during charging. In this case, the output from the charger 9 can be increased to fully bring out the capacity of the charger, and the charging time can be extremely prolonged and the discharge from the battery can be prevented. In addition, since the output from the charger 9 is controlled to decrease as the voltage difference (V_diff) between the target voltage (V_trg) and the battery voltage (V_bat) decreases, a constant voltage is applied when the load during charging is small. Control can be continued and the temperature rise of the battery 5 can be suppressed.

It is a schematic block diagram of the electric vehicle which is one Embodiment of this invention. It is a block diagram which shows the structure of the charge control system of this invention. It is a flowchart which shows one form of the charge control by a control means. It is a characteristic view which shows the characteristic of the output of a battery and a charger at the time of charge control implementation and non-implementation concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Motor 5 Battery 9 Charger 12 Charger 24 Battery voltage detection means 30 Control means 31 Difference calculation means
V_bat battery voltage
V_trg target voltage
V_diff Voltage difference

Claims (2)

In a charging control device for an electric vehicle that can be driven by a motor driven by electric power supplied from a battery,
A charger connected to the battery and supplying current to the battery;
Battery voltage detection means for detecting the voltage of the battery;
A difference calculating means for calculating a voltage difference from the battery voltage detected by the battery voltage detecting means and a preset target voltage;
A charging control device for an electric vehicle, comprising: control means for controlling to increase or decrease the output of the charger according to the voltage difference calculated by the difference calculating means during charging by the charger.   The control means controls to increase the output from the charger as the difference between the target voltage and the battery voltage increases, and to decrease the output from the charger as the difference between the target voltage and the battery voltage decreases. The charging control device for an electric vehicle according to claim 1.

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