JP2011135628A - Chargeable vehicle and current control circuit thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of charging control, when charging a battery of a vehicle by means of a charging device. <P>SOLUTION: Upon receiving an instruction for applying a large current by a current control signal, a control section 17 controls switches SW1-SWn to be turned on and off so that the resistance value between input/output terminals of a current control circuit 12 becomes a minimum. Also, upon receiving instruction for applying a small current by a current control signal, the control section individually controls the switches SW1-SWn to be turned on and off so that the resistance value becomes a maximum. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rechargeable vehicle and a current control circuit thereof.

  Hybrid vehicles are becoming more popular and electric vehicles are being put to practical use. In an automobile using a battery as a power source of a drive motor, it is required to charge the battery in a short time using a charging device.

  In Patent Document 1, for example, in a vehicle battery charging device in which the charging condition is set according to the ambient temperature, the charging condition is short when the charging stop time is short so as not to be affected by the heat generated by the charging device itself. A charging device having a means for prohibiting the setting is described.

  In Patent Document 2, for example, in a vehicle charging device, in order to level the load on the AC power supply side and to enable rapid charging, a facility secondary battery is provided. It is described that a fast charging current is supplied to a secondary battery of a load.

Japanese Patent No. 4030932 Japanese Patent No. 3211323

  By the way, when the vehicle battery is rapidly charged using the charging device, the charging current is controlled by an external charging device. Therefore, when a failure occurs on the charging device side, a charging current more than necessary may be supplied to the battery, which may shorten the battery life.

  The subject of this invention is improving the reliability of charge control at the time of charging the battery of a vehicle with a charging device.

The present invention provides a control unit that outputs charging state information indicating a charging state of a battery and current control information indicating a charging current in a chargeable vehicle that charges the battery with an external charging device;
A current control circuit that is connected in series with the battery and controls a current supplied from the charging device based on a current value obtained from the current control information or the charge state information;

  According to this chargeable vehicle, the charging current can be limited even when the charging current supplied from the external charging device is not appropriate. Thereby, the reliability of charge control can be improved and battery overcharge and the like can be prevented.

  In the above rechargeable vehicle, the current control circuit includes a plurality of switches and a plurality of resistors each connected in series with two or more of the plurality of switches, and the plurality of switches and the plurality of switches. Each of the resistors is connected in parallel, and the plurality of switches are on / off controlled based on the current control information or the charge state information.

  With this configuration, the output current of the current control circuit can be limited by individually turning on and off the plurality of switches based on the current control information.

  According to the present invention, it is possible to prevent the battery from being overcharged by limiting the charging current supplied from the external charging device to the vehicle battery.

FIG. 1A is a diagram illustrating a charging system, and FIG. 1B is a diagram illustrating a configuration of a current control circuit. FIG. 2A is a diagram illustrating a configuration of a charging stand, and FIG. 2B is a diagram illustrating a configuration of a charging control circuit. It is a flowchart which shows operation | movement of the charge control circuit of a vehicle. It is a flowchart which shows operation | movement of a charging stand. It is a figure which shows the other example of a current control circuit.

  Hereinafter, embodiments of the invention will be described. FIG. 1A is a diagram illustrating an example of a charging system, and FIG. 1B is a diagram illustrating a configuration of a current control circuit. This embodiment relates to a rechargeable vehicle such as a hybrid car or an electric vehicle.

  A rechargeable vehicle (hereinafter referred to as a vehicle) is provided with a battery pack 11, a current control circuit 12, and an ECU (electronic control unit) 13 that serve as a power source for driving a motor for traveling. A charging stand (charging device) 14 is provided on the infrastructure side. At the time of charging, a charging current is supplied from the power supply line 15 of the charging stand 14 to the power supply line 16 of the vehicle by inserting the charging plug of the charging stand 14 into the charging socket of the vehicle.

  The vehicle-side ECU (corresponding to the control unit) 13 charges charging state information SOC (State Of Charge) indicating the charging state of the battery pack 11 and a current control signal (current control information) that gives an instruction of charging current. Output to the stand 14. Further, the ECU 13 outputs a current control signal to the current control circuit 12. The charge state information SOC and the current control signal are transmitted by, for example, a dedicated communication line or power supply lines 16 and 15 to which a charging current is supplied.

  The current control circuit 12 has, for example, a plurality of switches and a plurality of resistors, and controls the on / off of the switches to change the resistance value of the entire circuit and limit the current. The switch is ON / OFF controlled based on the current control signal.

  When the charging stand 14 receives the charging state information and the current control signal from the ECU 13, the charging stand 14 variably controls the charging current supplied to the battery pack 11 based on one or both of the information. At the time of charging, the power line 16 on the vehicle side and the power line 15 on the charging stand side are connected, and the charging current is supplied to the battery pack 11 via the power lines 15 and 16 and the current control circuit 12.

  FIG. 1B is a diagram illustrating an example of the configuration of the current control circuit 12. The current control circuit 12 includes n switches SW1 to SWn and n-1 resistors R2 to Rn. The switches SW2 to SWn and the resistors R2 to Rn are connected in series, and the switches connected in series. A set of SW2 to SWn and resistors R2 to Rn and the switch SW1 are connected in parallel. The switches SW1 to SWn are on / off controlled by a signal generated from the current control signal by the control unit 17.

  Note that the control of the switches SW1 to SWn is not necessarily performed by the control unit 17, and for example, the ECU 13 may output a signal for turning on and off the switches SW1 to SWn individually instead of the current control signal. . In that case, the control part 17 becomes unnecessary.

  For example, when the current control signal instructs to flow a large current, the control unit 17 turns on the switch SW1 and turns off the other switches SW2 to SWn to the control terminals of the switches SW1 to SWn. give. As a result, the large current output from the charging stand 14 passes through the current control circuit 12 and is supplied to the battery pack 11.

  When it is instructed to flow a small current by the current control signal, the control unit 17 turns on the switch SW3 and supplies a control signal for turning off the other switches to the control terminals of the switches SW1 to SWn. In this case, even when a current (medium current or large current) larger than the current indicated by the current control signal is output from the charging stand 14, the output current of the current control circuit 12 is limited by the resistor R3, so that the current value Becomes smaller. Thereby, it is possible to prevent the charging current more than necessary from being supplied to the battery pack 11 and to prevent the battery pack 11 from being overcharged.

FIG. 2A is a diagram illustrating a configuration of the charging stand 14. The charging stand 14 includes a charging control circuit 21, an ammeter 22, and a direct current generation circuit 23.
The DC generation circuit 23 converts an AC voltage output from the AC power supply 24 into a DC voltage, and outputs a DC current instructed from the charge control circuit 21.

  The charging control circuit 21 outputs a control signal for controlling the output current of the DC generation circuit 23 based on the charging state information SOC and the current control signal given from the vehicle side. Then, the output current of the DC generation circuit 23 is controlled so that the output current of the DC generation circuit 23 measured by the ammeter 22 becomes a target current value.

  FIG. 2B is a diagram illustrating an example of a circuit configuration of the charge control circuit 21. The charge control circuit 21 compares the appropriate current value obtained from the charge state information SOC with the current value determined by the current control signal, and appropriately controls the output current of the charging stand 14.

The charge control circuit 21 includes a decoder 31 that decodes the charge state information SOC and the current control signal, an appropriate current value calculation unit 32 that calculates an appropriate charge current value, and a comparison circuit 33.
The decoder 31 decodes the charging state information SOC and the current control signal transmitted from the vehicle, outputs the charging state information to the appropriate current value calculation unit 32, and outputs the current control signal to the comparison circuit 33.

The appropriate current value calculation unit 32 calculates a current value suitable for charging the battery pack 11 based on the charge state information SOC and outputs the calculated current value to the comparison circuit 33.
The comparison circuit 33 compares the appropriate current value output from the appropriate current value calculation unit 32 with the current value indicated by the current control signal output from the decoder 31, and outputs the direct current generation circuit 23 based on the comparison result. A control signal for controlling the current is output.

  The comparison circuit 33 compares the appropriate current value calculated from the charge state information with the current value required by the current control signal, and when the two are far from each other, the output current of the DC generation circuit 23 is compared with the two compared current values. Control is performed so that the current value is the smaller of the current values.

  Thereby, even when the current control signal or the charge state information is incorrect and a current value larger than the current value necessary for charging is given to the comparison circuit 33, the current value calculated from the charge state information SOC and the current control signal are used. The output current of the direct current generating circuit 23 is controlled so that the current value is the smaller of the instructed current values.

  FIG. 3 is a flowchart showing the operation of the current control circuit 12 on the vehicle side. The following processing is executed by, for example, the control unit 17 or the ECU 13 in FIG. The current control function of the current control circuit 12 may be realized by hardware or software. Hereinafter, a case where the number of switches SW of the current control circuit 12 is three will be described as an example.

The control unit 17 determines whether a large current is requested as a charging current based on a current control signal output from the ECU 13 (S11).
When a large current is requested by the current control signal (S11, YES), the process proceeds to step S12, where the switch SW1 is turned on and the other switches SW2, SW3 are turned off. When it is not a request for a large current (S11, NO), the process of step S11 is repeated.

  Next, it is determined whether or not a medium current is requested by the current control signal (S13). When a medium current is requested by the current control signal (S13, YES), the process proceeds to step S14, where the switch SW2 of the current control circuit 12 is turned on and the other switches SW1, SW3 are turned off. When it is not a request for medium current (S13, NO), the process returns to step S12.

  By the processing in steps S13 and S14, for example, even when the charging current supplied from the charging station 14 is larger than the medium current required by the current control signal, the switches SW1 to SW3 of the current control circuit 12 are controlled by the current control signal. By switching to the resistance value R1 larger than the resistance value “0” when a large current is required, it is possible to prevent an excessive charging current from being supplied to the battery pack 11.

  Next, it is determined whether a small current is requested by the current control signal (S15). When a small current is requested by the current control signal (S15, YES), the process proceeds to step S16, where the switch SW3 of the current control circuit 12 is turned on and the other switches SW1, SW2 are turned off. On the other hand, when it is not a request for a small current (S15, NO), the process returns to step S14.

  By the processing in steps S15 and S16 described above, for example, even when the charging current supplied from the charging station 14 is larger than the current required by the current control signal (in this case, a small current), the switch SW1 of the current control circuit 12 is used. By switching SW3 with the current control signal and switching to a resistance value R3 that is larger than the resistance value R2 at the middle current, it is possible to prevent the battery pack 11 from being supplied with an excessive charging current.

  Next, it is determined whether or not charging stop is requested (S17). When the charge stop is requested (S17, YES), the process is ended there. If it is not a request to stop charging (S17, NO), the process returns to step S16.

  Next, FIG. 4 is a flowchart showing the operation of the charging stand 14. An appropriate current value suitable for the state of charge is calculated from the state of charge information SOC received from the vehicle (S21). The appropriate current value obtained by calculation at this time is assumed to be I1. The process of step S21 corresponds to the operation of the appropriate current value calculation unit 32.

Next, the current value I2 requested by the current control signal received from the vehicle is compared with the appropriate current value I1 calculated from the charging state information to determine whether I1 ≧ I2 (S22).
When the appropriate current value I1 obtained from the charge state information SOC is equal to or larger than the current value I2 required by the current control signal (I1 ≧ I2), the process proceeds to step S23, and the current value I2 determined by the current control signal is charged. Output as current.

When the appropriate current value I1 is less than the current value I2 required by the current control signal (I1 <I2), the process proceeds to step S24, and the smaller current value I1 is output as the charging current.
That is, when the current value required by the current control signal is larger than the appropriate current value calculated from the charge state information SOC, charging is performed with the appropriate current value I1 having a small current value. The processing in steps S22 to S24 described above corresponds to the operation of the comparison circuit 33.

  According to the above-described embodiment, even when the output current of the charging station 14 is larger than the current value required by the current control signal due to a communication failure between the vehicle and the charging station 14, the current control circuit on the vehicle side. 12 can limit the charging current. Thereby, it is possible to prevent an excessive current from being supplied to the battery pack 11 and a decrease in the life of the battery pack 11.

  FIG. 5 is a diagram illustrating another example of the current control circuit 41. This current control circuit 41 is an example when resistors R1 to Rn are connected in series to switches SW1 to SWn, respectively. A resistor R1 is connected in series to the switch SW1, and a resistor R2 is connected in series to the switch SW2. Similarly, resistors R3 to Rn are connected in series to the switches SW3 to SWn, respectively. The resistance values of the resistors R1 to Rn have a relationship of R1 <R2 <R3.

  The switches SW1 to SWn are turned on and off by the current control signal. For example, when the charging current required by the current control signal is the maximum value, all the switches SW1 to SWn are turned on and the resistors R1 to Rn are connected in parallel. It will be in the state. At this time, the resistance value between the input and output terminals of the current control circuit 41 is minimized (the resistance value is the reciprocal of (1 / R1) + (1 / R2) + .. + (1 / Rn)).

  When the current control signal requires the second largest current, the switch SW1 is on and the other switches SW2 to SWn are off. In this case, the resistance value between the input and output terminals of the current control circuit 41 is the second smallest value R1.

  The current control circuit 41 can limit the current value supplied to the battery pack 11 by switching the resistance value based on the current control signal output from the ECU 13. Thereby, even when the current value supplied from the charging stand 14 exceeds the current value necessary for charging, the charging current of the battery pack 11 can be suppressed.

  In the above embodiment, the output current of the current control circuit 12 is controlled based on the current control signal, but the output current may be controlled based on the charge state information SOC.

11 Battery pack 12 Current control circuit 13 ECU
14 Charging stand 17 Control unit

Claims (4)

In a rechargeable vehicle that charges a battery with an external charging device,
A control unit that outputs charging state information indicating a charging state of the battery and current control information indicating a charging current;
A chargeable vehicle comprising: a current control circuit that is connected in series with the battery and that controls a current supplied from the charging device based on a current value obtained from the current control information or the charge state information.   The current control circuit includes a plurality of switches and a plurality of resistors connected in series with two or more of the plurality of switches, and the plurality of switches and the plurality of resistors are each in parallel. The rechargeable vehicle according to claim 1, wherein the plurality of switches are on / off controlled based on the current control information or the charge state information.   The current control circuit individually turns on and off the plurality of switches so as to output the maximum current when the current control information or the charging state information instructs supply of the first largest charging current. When the control is performed so that the resistance value is minimized, and the current control information or the charging state information instructs supply of the second largest charging current, the plurality of switches are individually turned on and off to set the resistance value. The rechargeable vehicle according to claim 2, wherein the rechargeable vehicle is controlled to be second smallest. A vehicle current control circuit for charging a battery with an external charging device,
Obtain at least one of charging state information indicating a charging state of the battery and current control information indicating a charging current, and supply from the charging device based on the acquired current control information or a current value obtained from the charging state information Current control circuit for controlling the current to be generated.

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