JP2009089577A - Electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle which can reduce the charging time for main battery, while securing power to an auxiliary battery, when it is charged with an external power supply. <P>SOLUTION: The electric vehicle 1 includes the main battery 20 which supplies power to a motor 10, the auxiliary battery 40 which supplies power to electrical equipment 41 in the vehicle 1; a down-converter 50 which reduces power supplied from the main battery 20 in voltage, to a supply power with a lowered voltage to the auxiliary battery 40; a first charger 60 which supplies power from the external power supply to the main battery 20; a second charger 70, which converts power from the external power supply into power with a given voltage to supply the converted power to the auxiliary battery 40; a controller 2 which controls the down-converter 50; and a voltage sensor 42 which detects the voltage of the auxiliary battery 40. The second charger 70 supplies power to the auxiliary battery 40 via a constant-voltage converter that converts the voltage of the external power supply into a constant voltage which is equal to or higher than the given voltage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric vehicle. Specifically, the present invention relates to an electric vehicle equipped with a battery as a power source.

  Conventionally, an electric vehicle is known. An electric vehicle includes, for example, a motor that drives a vehicle, a main battery that drives the motor, and an auxiliary battery that drives electric devices.

  The motor is connected to the main battery via an inverter. The auxiliary battery is connected to the main battery via a DC / DC converter in parallel with the motor. Further, a charger is connected to the main battery.

  In such an electric vehicle, when a charger is connected to an external power supply, power is supplied from the outside to the main battery, and the main battery is charged. A part of the supplied power is supplied by a DC / DC converter. The voltage is stepped down and supplied to the auxiliary battery, and the auxiliary battery is also charged (see Patent Document 1).

The reason why the auxiliary battery is charged by the external power supply is as follows.
An automobile is provided with electric devices that are driven by electric power supplied from an auxiliary battery. In particular, an electric vehicle is provided with a DC / DC converter and a circuit for controlling electric power supplied from an external power source, and more electric devices are provided than a gasoline vehicle.
Therefore, in the electric vehicle, the electric power consumption of the electric device is larger than that of the gasoline vehicle, and the storage amount of the auxiliary battery is likely to decrease. When the amount of power stored in the auxiliary battery is reduced, even if an attempt is made to charge the main battery by connecting a charger to the external power supply, the drive of the circuit that controls the charging from the external power supply stops, and the charging of the main battery stops halfway There is a fear.
Therefore, charging of the auxiliary battery is also charged with power from the external power source to prevent the main battery from stopping charging.

JP-A-8-98324

  However, when the auxiliary battery is charged as described above, the DC / DC converter is driven. Even if electric power is supplied from an external power source, the DC / DC converter takes out electric power, so that sufficient electric power supplied to the main battery cannot be secured. Therefore, there is a possibility that the charging time becomes long.

  An object of the present invention is to provide an electric vehicle capable of shortening a charging time of a main battery while securing power of an auxiliary battery when charging from an external power source.

  An electric vehicle (for example, an electric vehicle 1 described later) according to the present invention includes a main battery (for example, a main battery 20 described later) for supplying electric power to a motor (for example, a motor 10 described later), and an electric device (for example, an internal vehicle). , An auxiliary battery for supplying electric power to an electric device 41 described later, a step-down means for lowering electric power supplied from the main battery and supplying the electric power to the auxiliary battery (for example, a downverter 50 described later), and the main battery And external charging means for charging the auxiliary battery with power from an external power source, voltage detecting means for detecting the voltage of the auxiliary battery (for example, a voltage sensor 42 described later), and the voltage of the auxiliary battery is equal to or higher than a predetermined voltage value The control means (for example, the control device 2 described later) for stopping the driving of the step-down means. The external charging means is connected to the main battery side from the step-down means, and supplies a first connection line (for example, a first charger 60 described later) for supplying power from an external power source to the main battery, A second connection line (for example, a second charger 70 described later) that is connected to the auxiliary battery side from the step-down means and supplies electric power from an external power source to the auxiliary battery, and the second connection line includes: The voltage is supplied to the auxiliary battery via a constant voltage converter that converts a voltage of an external power source into a constant voltage value equal to or higher than the predetermined voltage value.

  According to this invention, the external charging means is configured by the first connection line that supplies the power of the external power source to the main battery and the second connection line that supplies the power of the external power source to the auxiliary battery. Furthermore, the voltage of the external power supply was supplied to the auxiliary battery through the second connection line via a constant voltage converter that converts the voltage of the external power source to a constant voltage value equal to or higher than a predetermined voltage value.

Therefore, the operation of this electric vehicle is as follows.
When the amount of power stored in the main battery and the auxiliary battery decreases, the external charging means described above is connected to an external power source to charge the main battery and the auxiliary battery.
Here, for example, when only the first connection line is connected to the external power source for charging, the voltage of the auxiliary battery is reduced to less than a predetermined voltage value in order to supply power to other electrical devices. Therefore, the step-down means is driven by the control means, and the electric power supplied from the external power supply through the first connection line is not only supplied to the main battery but also supplied to the auxiliary battery via the step-down means.

  On the other hand, for example, when charging is performed by connecting the second connection line to the external power supply in addition to the first connection line, the drive of the step-down means is stopped by the control means, and the power supplied from the external power supply through the first connection line is It is supplied only to the main battery. At the same time, the power supplied from the external power source through the second connection line is supplied to the auxiliary battery.

  As described above, when the power of the auxiliary battery can be secured by monitoring the voltage of the auxiliary battery and connecting the second connection line to an external power source, the power supplied through the first connection line is supplied to the main battery. Therefore, the charging time of the main battery can be shortened while securing the power of the auxiliary battery.

  According to the present invention, for example, when only the first connection line is connected to the external power source for charging, the voltage of the auxiliary battery is reduced to less than a predetermined voltage value in order to supply power to other electrical devices. Therefore, the step-down means is driven by the control means, and the electric power supplied from the external power supply through the first connection line is not only supplied to the main battery but also supplied to the auxiliary battery via the step-down means. On the other hand, for example, when the second connection line is connected to the external power supply and charged in addition to the first connection line, the drive of the step-down means is stopped by the control means, and the power supplied from the external power supply through the first connection line is It is supplied only to the main battery. At the same time, the power supplied from the external power source through the second connection line is supplied to the auxiliary battery. As described above, when the power of the auxiliary battery can be secured by monitoring the voltage of the auxiliary battery and connecting the second connection line to an external power source, the power supplied through the first connection line is supplied to the main battery. Therefore, the charging time of the main battery can be shortened while securing the power of the auxiliary battery.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of an electric vehicle 1 according to an embodiment of the present invention.
The electric vehicle 1 includes a motor 10, a main battery 20, an inverter 30, an auxiliary battery 40, a downverter 50 as a step-down means, a first charger 60 as a first connection line, and a second connection line. The second charger 70 and the control device 2 as control means for controlling the downverter 50 are provided.

The motor 10 drives the wheels.
The main battery 20 stores electric power and outputs the stored electric power. The main battery 20 is provided with a voltage sensor 21 that detects the voltage of the main battery 20 and a current sensor 22 that detects the current of the main battery 20.

The inverter 30 converts the supplied DC power into AC power and outputs it, and has a smoothing capacitor 31 built-in.
The motor 10 is connected to the main battery 20 via the inverter 30, whereby the main battery 20 supplies power to the motor 10.

A battery contactor 80 is provided between the main battery 20 and the inverter 30.
The battery contactor 80 is connected to the positive side main contactor 81 and the precharge contactor 83 that connect the positive terminal of the main battery 20 to the positive terminal of the inverter 30, and the negative terminal of the main battery 20 is connected to the negative terminal of the inverter 30. A negative-side main contactor 82 and a resistor 84 connected in series to the precharge contactor 83.
The precharge contactor 83 and the resistor 84 are connected to the positive main contactor 81 in parallel.

The auxiliary battery 40 stores electric power and supplies the stored electric power to the electric device 41 in the vehicle. The electric equipment 41 includes, for example, indoor lamps and meters. The auxiliary battery 40 is connected to the main battery 20 via the downverter 50 in parallel with the motor 10. The auxiliary battery 40 is provided with a voltage sensor 42 as voltage detecting means for detecting the voltage of the auxiliary battery 40.
The downverter 50 is driven by the power of the auxiliary battery 40, and steps down the power supplied from the main battery 20 and supplies it to the auxiliary battery 40.
The auxiliary battery 40 supplies power not only to the electric device 41 and the downverter 50 but also to the control device 2, the battery contactor 80, and an inlet contactor 90 described later.

  The control device 2 drives the downverter 50 when the voltage detected by the voltage sensor 41 is less than the predetermined voltage value V, and the voltage detected by the voltage sensor 41 is equal to or higher than the predetermined voltage value V. Then, the driving of the downverter 50 is stopped. The reason why the hysteresis is provided in the determination threshold for downverter driving in this way is to prevent hunting during downverter driving.

The first charger 60 is connected to the main battery 20 side from the downverter 50 and supplies the power of the external power source to the main battery 20.
An inlet contactor 90 is provided between the first charger 60, the downverter 50 and the main battery 20.
Inlet contactor 90 connects and disconnects the positive terminal of first charger 60 to the positive terminal of downverter 50 and main battery 20.

  The second charger 70 is connected to the auxiliary battery 40 side from the downverter 50. The second charger 70 has a built-in constant voltage converter that converts the power of the external power source into a predetermined voltage value V3, and supplies the converted power of the voltage value V3 to the auxiliary battery 40. The voltage value V3 is a value larger than the predetermined voltage value V for the control device 2 described above.

The operation of the electric vehicle 1 will be described with reference to the flowchart of FIG.
First, it is determined whether or not the charging mode is set (ST1). If this determination is NO, the process ends. If YES, the process proceeds to ST2.

In ST2, the battery contactor 80 is connected. Specifically, first, the precharge contactor 83 is connected to precharge the smoothing capacitor 31 of the inverter 30, and then the main contactor 81 is connected.
In ST3, the inlet contactor 90 is connected.

  In ST4, the voltage of the auxiliary battery 40 is detected by the voltage sensor 42, and the control device 2 determines whether or not the voltage of the auxiliary battery 40 is less than a predetermined voltage value V. If this determination is YES, the downverter 50 is driven because the power of the auxiliary battery 40 is not sufficiently secured (ST5). On the other hand, when this determination is NO, since the power of the auxiliary battery 40 is sufficiently secured, the driving of the downverter 50 is stopped (ST6).

In ST7, it is determined whether charging of the main battery is completed. If this determination is NO, the process returns to ST4, and if YES, the process proceeds to ST8.
In ST8, the inlet contactor 90 is shut off, and then in ST9, the battery contactor 80 is shut off.

Hereinafter, a timing chart of the electric vehicle 1 will be described with reference to FIGS.
Here, in order to prevent hunting at the time of downverter driving, hysteresis is provided in the above-described determination threshold V of downverter driving. Specifically, the control device outputs a command to turn on the downverter when the voltage of the auxiliary battery falls below V1, and outputs a command to turn off the downverter when the voltage of the auxiliary battery exceeds a predetermined value V2. .

FIG. 3 is a timing chart of the electric vehicle 1 when only the first charger is connected to the external power source.
At time t0, the ignition is turned on, so that the voltage of the auxiliary battery rises from zero, but is between V1 and V2 because the second charger is not connected to the external power source. Since the auxiliary battery supplies electric power to the electric device, the voltage value of the auxiliary battery starts to gradually decrease.

  Thereafter, at time t1, when the smoothing capacitor of the inverter is precharged, an off command for the downverter drive flag is output in order to prevent power from flowing to the downverter side. Thereafter, the precharge contactor is connected at time t2, and the main contactor is connected at time t3.

  At time t4, it is determined whether or not to drive the downverter. Here, since the voltage value of the auxiliary battery is less than V1, a command to turn on the downverter is output. The downverter drive flag is turned on according to the downverter on command, and the power consumption of the downverter becomes W1. In addition, since a part of the electric power supplied from the first charger is supplied to the auxiliary battery via the downverter, the voltage value of the auxiliary battery starts to rise.

At time t5, the inlet contactor is connected.
At time t6, charging is started. Here, since the voltage value of the auxiliary battery exceeds V2, a command to turn off the downverter is output, and according to the downverter off command, the downverter drive flag is turned off, and the power consumption of the downverter becomes zero. Thereby, in order to supply electric power to an electric equipment, the voltage value of an auxiliary battery begins to fall. Further, since all the power supplied from the first charger is supplied to the main battery, the charging power of the main battery becomes W3, the current value of the main battery becomes I2, and the voltage value of the main battery starts to rise. .

At time t7, since the voltage value of the auxiliary battery is less than V1, a command to turn on the downverter is output.
At time t8, the downverter drive flag is turned on in accordance with the downverter on command, and the power consumption of the downverter is W1. As a result, the voltage value of the auxiliary battery starts to rise. On the other hand, the charging power of the main battery is W2, the current value of the main battery is I1, and the rate of increase of the voltage value of the main battery decreases.

At time t9, since the voltage value of the auxiliary battery exceeds V2, a command to turn off the downverter is output.
At time t10, the downverter drive flag is turned off in accordance with the downverter turn-off command, and the power consumption of the downverter becomes zero. Thereby, in order to supply electric power to an electric equipment, the voltage value of an auxiliary battery begins to fall. On the other hand, since all the power supplied from the first charger is supplied to the main battery, the charging power of the main battery is W3, the current value of the main battery is I2, and the rate of increase of the voltage value of the main battery Will increase.

Thereafter, at time t11, since the voltage value of the auxiliary battery becomes less than V1, a command to turn on the downverter is output.
At time t12, the downverter drive flag is turned on in accordance with the downverter on command, and the power consumption of the downverter is W1. As a result, the voltage value of the auxiliary battery starts to rise. Further, the voltage of the main battery becomes V4, and charging is completed. Thereby, the charging power of the main battery becomes zero, and the current value of the main battery becomes zero.

  At time t13, since the voltage value of the auxiliary battery exceeds V2, the same operation as at time t9 is performed, and at time t14, the same operation as at time t10 is performed.

At time t15, the ignition is turned off, the voltage of the auxiliary battery becomes zero, and a command to turn off the downverter is output.
Thereafter, at time t16, the inlet contactor and the battery contactor are released.

FIG. 4 is a timing chart of the electric vehicle 1 when the second charger is connected to the external power source in addition to the first charger.
At time t0, the ignition is turned on. Then, the voltage of the auxiliary battery becomes V3 because the second charger is connected to the external power source.

  Thereafter, at time t1, when the smoothing capacitor of the inverter is precharged, an off command for the downverter drive flag is output in order to prevent power from flowing to the downverter side. Thereafter, the precharge contactor is connected at time t2, and the battery contactor is connected at time t3.

  At time t4, it is determined whether or not to drive the downverter. Here, since the voltage of the auxiliary battery exceeds V2, a command to turn off the downverter is output. In accordance with the downverter off command, the downverter drive flag is still off and the power consumption of the downverter remains zero.

  At time t5, the inlet contactor is connected, and at time t6, charging is started and the voltage value of the main battery starts to rise. Here, since all the power supplied from the first charger is supplied to the main battery, the charging power of the main battery is W3, and the current value of the main battery is I2.

  At time t7, the voltage of the main battery becomes V4 and charging is completed. Thereafter, at time t8, the ignition is turned off and the voltage of the auxiliary battery becomes zero. At time t9, the inlet contactor and the battery contactor are released.

  As described above, when only the first charger is connected to the external power source, charging of the main battery is completed at time t12 (see FIG. 3), whereas the first charger and the second charger are connected to the external power source. Since the main battery is completely charged at time t7, the charging time can be shortened.

FIG. 5 is a timing chart of the electric vehicle 1 when the second charger is removed in the middle after the second charger is connected to the external power source in addition to the first charger.
At time t0, the ignition is turned on. Then, the voltage of the auxiliary battery becomes V3 because the second charger is connected to the external power source.

  Thereafter, at time t1, when the smoothing capacitor of the inverter is precharged, an off command for the downverter drive flag is output in order to prevent power from flowing to the downverter side. At time t2, the precharge contactor is connected, and at time t3, the battery contactor is connected.

  At time t4, it is determined whether or not to drive the downverter. Here, since the voltage of the auxiliary battery exceeds V2, a command to turn off the downverter is output. In accordance with the downverter off command, the downverter drive flag is still off and the power consumption of the downverter remains zero.

  At time t5, the inlet contactor is connected, and at time t6, charging is started and the voltage value of the main battery starts to rise. Here, since all the power supplied from the first charger is supplied to the main battery, the charging power of the main battery is W3, and the current value of the main battery is I2.

  At time t7, the second charger is removed. Then, in order to supply electric power to the electric device, the voltage value of the auxiliary battery starts to decrease.

  At time t8, since the voltage value of the auxiliary battery becomes less than V1, a command to turn on the downverter is output. At time t9, the downverter drive flag is turned on according to the downverter on command, and the power consumption of the downverter is W1. As a result, a part of the power supplied from the first charger is supplied to the auxiliary battery via the downverter, so that the voltage value of the auxiliary battery starts to rise. On the other hand, the charging power of the main battery is W2, the current value of the main battery is I1, and the rate of increase of the voltage value of the main battery decreases.

  At time t10, since the voltage value of the auxiliary battery exceeds V2, a command to turn off the downverter is output. At time t11, the downverter drive flag is turned off in accordance with the downverter off command, and the power consumption of the downverter becomes zero. Thereby, in order to supply electric power to an electric equipment, the voltage value of an auxiliary battery falls. On the other hand, since all the power supplied from the first charger is supplied to the main battery, the charging power of the main battery is W3, the current value of the main battery is I2, and the rate of increase of the voltage value of the main battery is Increase.

  Since the voltage value of the auxiliary battery becomes less than V1 at time t12, the same operation as at time t8 is performed, and at time t13, the same operation as at time t9 is performed.

Thereafter, at time t14, the voltage of the main battery becomes V4, so that charging is completed, and the charging power of the main battery becomes zero. Also, the ignition is turned off.
Also, the voltage of the auxiliary battery becomes zero, and a command to turn off the downverter is output. In accordance with this downverter turn-off command, the downverter drive flag is turned off at time t15, the power consumption of the downverter becomes zero, and the inlet contactor and battery contactor are released at time t16.

  As described above, when only the first charger is connected to the external power source, the charging of the main battery is completed at time t12 (see FIG. 3), whereas the second charger is connected in addition to the first charger. When the second charger is removed halfway after being connected to the external power source, charging of the main battery is completed at time t14, so that the charging time can be shortened.

According to this embodiment, there are the following effects.
(1) When the storage amounts of the main battery 20 and the auxiliary battery 40 are reduced, the first charger 60 and the second charger 70 are connected to an external power source, and the main battery 20 and the auxiliary battery 40 are charged.
Here, for example, when only the first charger 60 is connected to an external power source for charging, the voltage of the auxiliary battery 40 decreases to less than a predetermined voltage value V1 in order to supply power to other electric devices. Therefore, the downverter 50 is driven by the control device 2, and the power supplied from the external power source through the first charger 60 is not only supplied to the main battery 20 but also to the auxiliary battery 40 via the downverter 50. Supplied.

  On the other hand, for example, when the second charger 70 is connected to an external power source and charged in addition to the first charger 60, the voltage of the auxiliary battery 40 becomes a predetermined voltage value V2 or more. Therefore, the driving of the downverter 50 is stopped by the control device 2, and the power supplied from the external power source through the first charger 60 is supplied only to the main battery 20. At the same time, the power supplied from the external power source through the second charger 70 is supplied to the auxiliary battery 40.

  As described above, when the power of the auxiliary battery 40 can be secured by monitoring the voltage of the auxiliary battery 40 and connecting the second charger 70 to an external power source, the voltage is supplied through the first charger 60. Since power is supplied only to the main battery 20, the charging time of the main battery 20 can be shortened while securing the power of the auxiliary battery 40.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

1 is a block diagram of an electric vehicle according to an embodiment of the present invention. It is a flowchart of operation | movement of the electric vehicle which concerns on the said embodiment. It is a timing chart at the time of connecting only the 1st connection line to an external power supply about the electric vehicle concerning the embodiment. It is a timing chart at the time of connecting the 2nd connection line to the external power supply in addition to the 1st connection line about the electric vehicle concerning the embodiment. About the electric vehicle which concerns on the said embodiment, after connecting a 1st connection line and a 2nd connection line to an external power supply, it is a timing chart at the time of removing a 2nd connection line in the middle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Control apparatus (control means)
DESCRIPTION OF SYMBOLS 10 Motor 20 Main battery 40 Auxiliary battery 41 Electric equipment 42 Voltage sensor (voltage detection means)
50 Downverter
60 First charger (first connection line)
70 Second charger (second connection line)

Claims (1)

A main battery that supplies power to the motor;
An auxiliary battery that supplies power to the electrical equipment inside the vehicle;
Step-down means for stepping down the power supplied from the main battery and supplying it to the auxiliary battery;
External charging means for charging the main battery and the auxiliary battery with electric power from an external power source;
Voltage detection means for detecting the voltage of the auxiliary battery;
When the voltage of the auxiliary battery is equal to or higher than a predetermined voltage value, an electric vehicle comprising control means for stopping driving of the step-down means,
The external charging means is connected to the main battery side from the step-down means, and a first connection line for supplying power from an external power source to the main battery;
A second connection line connected to the auxiliary battery side from the step-down means and supplying electric power from an external power source to the auxiliary battery;
The electric vehicle according to claim 2, wherein the second connection line supplies the auxiliary battery with a voltage through a constant voltage converter that converts a voltage of an external power source into a constant voltage value equal to or higher than the predetermined voltage value.

Images