JP2004007985A - Battery connection control device for electric vehicles - Google Patents

Abstract

[Object] To prevent a large current from flowing even when a safety plug is removed in a state where a main battery and an inverter are directly connected and then re-installed.
When the [configuration] At least relay A becomes the detection output V _B substantially zero voltage sensor 24 [V] in a state of ON, turns off the at least relay A it is regarded as a safety plug 18 is removed.
[Selection diagram] Fig. 1

Description

[0001]
[Industrial applications]
The present invention relates to a battery connection control device for an electric vehicle that controls a connection between a battery mounted on the electric vehicle and outputting a DC voltage and a device to be driven (eg, an inverter) driven by the voltage output from the battery. In particular, the present invention relates to control of connection between a battery including a maintenance plug and a device to be driven.
[0002]
[Prior art]
An electric vehicle is a vehicle that travels by driving a traveling motor with electric power supplied from a vehicle-mounted battery. Since the traveling motor is a high-output motor, the output voltage (discharge voltage) of the battery for supplying drive power to the motor must be high, and the amount of discharge current must also be large. Extreme care must be taken in handling such batteries, and various proposals have been made from the viewpoint of preventing various accidents.
[0003]
FIG. 7 shows a main configuration of an electric vehicle according to a conventional example. The three-phase AC motor 10 shown in FIG. 1 is a running motor of an electric vehicle, and receives driving power from an in-vehicle main battery 12 via an inverter 14 to rotate. The inverter 14 includes a predetermined number (six in the figure) of switching elements 16, and these switching elements 16 are turned on / off by a switching control signal supplied from a motor ECU (not shown). The motor ECU generates this switching control signal according to the output required of the motor 10. Therefore, by performing the control using the inverter 14, the output power (discharge power) of the main battery 12 can be converted into three-phase AC power to drive the motor 10, and the output of the motor 10 can be controlled. Can be.
[0004]
In this conventional example, from the viewpoint of preventing an accident relating to the main battery 12, two circuit measures are roughly divided.
[0005]
A first measure is that a safety plug 18 is provided on the main battery 12. The safety plug 18 is provided substantially at the center of the cell connection in the main battery 12 having a configuration in which a plurality of cells are connected in series. The safety plug 18 is in a mounted state when the main battery 12 is normally used, and a voltage appears at both ends of the main battery 12 in this state. When the safety plug 18 is removed, no voltage appears across the main battery 12. Therefore, at the time of an emergency or work such as mounting / repair of the main battery 12, safety can be ensured only by removing the safety plug 18. Regarding this technique, refer to Japanese Patent Publication No. 57-4063 previously proposed by the present applicant.
[0006]
The second measure is to provide two relays A and B and a current limiting resistor R for opening and closing the connection between the main battery 12 and the inverter 14, and control the opening and closing of the relays A and B by the vehicle ECU 20. It is a point. B of the two relays is provided so as to directly connect between the main battery 12 and the inverter 14 when turned on. Therefore, by turning on the relay B, the operation of the inverter 14 can be started. However, in order for the operation of the inverter 14 to be performed stably, the DC voltage supplied from the main battery 12 needs to be stable. Therefore, for example, the capacitor C having a capacity of about 14100 μF It is provided between the side terminals. Therefore, when the relay B is turned on in a state where the capacitor C is not charged, a large current flows due to rapid charging of the capacitor C. The relay A and the resistor R are provided to prevent this large current. Further, vehicle ECU 20 controls the on / off timing of relays A and B. Resistor R _d is a discharge resistor for discharging the capacitor C, by providing the discharge resistor R _d, thereby preventing electric shock of the operator during the repair and maintenance of the device for a drive system. In addition, it is preferable to provide an LED so as to light up until the charge (electrostatic energy) stored in the capacitor C becomes lower than a predetermined level.
[0007]
FIG. 8 shows a flow of the operation of the vehicle ECU 20 in this conventional example, particularly a flow of control of the junction box 22 executed at the time of starting the motor. The junction box 22 is a member configured by collecting relays and the like for controlling connections between various electric devices mounted on the electric vehicle. In addition to the relays A and B and the resistor R shown in FIG. For example, it has members related to the connection between the main battery 12 and the auxiliary battery and the connection between the main battery 12 and the air conditioner, but is not shown in FIG. 7 for simplicity.
[0008]
As shown in FIG. 8, vehicle ECU 20 starts controlling relays A and B in response to starter signal ST being turned on (100). That is, the contact control signal CONT is kept at the L value and the relays A and B are kept off until the starter signal ST is turned on in response to a key operation or the like by the vehicle operator. When the starter signal ST is turned on, the vehicle ECU 20 changes the contact control signal CONT to the H value (102). The junction box 22 receives the contact control signal CONT. As shown in FIG. 9, the relay A turns on in response to the value of the contact control signal CONT turning to the H value. After the value of the contact control signal CONT has turned to the H value, the relay B is turned on after a lapse of time sufficient for charging the capacitor C, for example, 700 msec.
[0009]
Therefore, immediately after the value of the contact control signal CONT changes to the H value, the main battery 12 and the inverter 14 are connected via the resistor R, and the capacitor C has a time constant determined by the values of the resistor R and the capacitor C. Is charged. At this time, since the charging current is limited by the resistor R, the discharging current of the main battery 12 does not become a large current. Furthermore, since the relay B is turned on after the capacitor C is charged, power consumption and heat generation by the resistor R do not cause much problem. Such a configuration and control can prevent generation of a large current.
[0010]
[Problems to be solved by the invention]
However, in the above configuration, if the safety plug is unplugged in a state where the main battery and the inverter are directly connected, the electric charge stored in the capacitor provided between the main battery side terminals of the inverter is discharged by the discharge resistor. Discharge in about 5 to 10 minutes. Thereafter, as shown in FIG. 9, when the safety plug is attached again, the discharge current of the main battery becomes large due to the charging of the capacitor. This led to sparking and could damage the safety plug.
[0011]
SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a maintenance plug (safety plug) is detached in a state where an on-vehicle driven device (for example, an inverter) is directly connected to an on-vehicle battery. It is another object of the present invention to prevent the discharge current of the battery from becoming large even when the battery is re-mounted.
[0012]
[Means for Solving the Problems]
In order to achieve such an object, the present invention provides a first vehicle in which a battery mounted on an electric vehicle and a capacitor are provided to open and close a connection between driven devices provided between battery-side terminals. A contact, a current limiting resistor connected in series to the first contact, and a second contact provided to open and close the connection between the battery and the device to be driven, and connected in parallel to the first contact and the current limiting resistor. Closing timing control means for controlling the opening and closing timing of the first and second contacts so that when the connection between the battery and the driven device is closed, the current flowing through the driven device is limited by the current limiting resistor; The connection between a battery that outputs a DC voltage only when a maintenance plug is attached to the battery and a device to be driven that is driven by the voltage output from the battery is controlled. A battery connection control device for an electric vehicle, comprising: detection means for detecting a state of attachment / detachment of a maintenance plug to / from a battery; and connection opening control means for opening at least a second contact when the maintenance plug is removed. It is characterized by.
[0013]
According to the present invention, the connection release control means is means for releasing the first and second contacts when the maintenance plug is removed, and the connection release control means releases the first and second contacts. And a connection restoration control means for closing the first and second contacts at a predetermined timing when the maintenance plug is attached after the connection.
[0014]
According to the present invention, the connection opening control means is means for opening only the second contact of the first and second contacts when the maintenance plug is detached, and the connection opening control means is provided with a second connection opening means. When the maintenance plug is attached after the contacts are opened, a connection restoration control unit that closes the second contacts at a predetermined timing is provided.
[0015]
According to the present invention, the detecting means further includes a third contact provided so as to be integrally attached to and detached from the maintenance plug, and when the third contact is opened, it is determined that the maintenance plug is detached, and when the third plug is closed, Means for determining that it has been mounted.
[0016]
According to the present invention, alternatively, the detecting means may include means for detecting the output voltage of the battery, and means for determining that the maintenance plug has been disconnected when the output voltage of the battery is lower than a predetermined value, and determining that the maintenance plug has been mounted when the output voltage of the battery is high. , Is characterized by having.
[0017]
[Action]
In the present invention, first, the first and second contacts are controlled so as to limit the current flowing through the device to be driven, and are closed at a predetermined timing. Further, the attachment / detachment state of the maintenance plug is detected by the detection means. Therefore, for example, when the maintenance plug is detached while the second contact is closed, it can be known based on the result of detection by the detection means. In the present invention, for example, when the maintenance plug is removed in a state where the second contact is closed, the connection opening control means is controlled to open at least the second contact. Therefore, even when the maintenance plug is re-attached thereafter, a circuit from the battery to the device to be driven (eg, an inverter) is not formed, or the circuit includes at least a current limiting resistor. It does not become a large current.
[0018]
In the present invention, when the maintenance plug is attached after the connection opening control unit opens the first and second contacts, the connection is restored so that the first and second contacts are closed at a predetermined timing. It is controlled by control means. Alternatively, when the maintenance plug is attached after the connection opening control unit opens only the second contact of the first and second contacts, the connection return control is performed so that the second contact is closed at a predetermined timing. Controlled by means. Therefore, the power of the battery can be supplied to the driven device without the trouble that the vehicle operator once turns off the start signal and turns it on again after the maintenance plug is re-mounted.
[0019]
In the present invention, the above-mentioned detecting means is further realized by an additional configuration of the maintenance plug. That is, if the third contact is provided so as to be integrally attached to and detached from the maintenance plug, it is determined that the maintenance plug has been detached when the third contact is opened, and that the maintenance plug is attached when the third contact is closed. Will be possible.
[0020]
In the present invention, the above-mentioned detecting means is realized by a voltage sensor or the like. That is, if a means for detecting the output voltage of the battery is provided, it is possible to determine that the maintenance plug has been removed when the output voltage of the battery is lower than a predetermined value, and to determine that the maintenance plug has been mounted when the output voltage is higher. Since the output voltage of the battery is generally monitored for control of a device to be driven or for charge control of the battery, additional hardware means is required to implement such a detection means. Is not necessary, and only the control procedure needs to be changed.
[0021]
【Example】
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The same components as those of the conventional example shown in FIGS. 7 to 9 are denoted by the same reference numerals, and description thereof will be omitted.
[0022]
FIG. 1 shows the configuration of an electric vehicle according to a first embodiment of the present invention. In this embodiment, and a voltage sensor 24 for detecting the voltage across the main battery 12 is provided, the output voltage V _B of the main battery 12 detected by the voltage sensor 24 is supplied to the vehicle ECU 20.
[0023]
FIG. 2 shows a control flow of the vehicle ECU in this embodiment, particularly a control flow of the junction box 22 when the motor 10 is started. As shown in this figure, in this embodiment, whether or a after step 102 described above has been executed, the output voltage V _B is approximately 0 of the main battery 12 detected by the voltage sensor 24 [V] Is determined (104). That is, while the safety plug 18 is mounted, the voltage across the main battery 12 does not become zero, but becomes zero when the safety plug 18 is removed. Therefore, at step 104, it is possible to know whether the safety plug 18 is attached or detached. As a result of the determination, if it is determined that _{V B} ≒ is 0 [V], the vehicle ECU20 is turn the value of the contact control signal CONT from the H value in L value (106). Then, in response, both relays A and B constituting junction box 22 are turned off. In this state, the connection between the main battery 12 and the inverter 14 is disconnected. Therefore, even if the user attaches the safety plug 18 in this state, a large current does not occur due to the charging of the capacitor C. Incidentally, if it is V _B ≒ 0 [V] is not satisfied in step 104, the operation is terminated as shown when the same Figure 2 the start signal ST is off.
[0024]
FIG. 3 shows a control flow of the vehicle ECU 20 in this embodiment, in particular, a control flow executed when the safety plug 18 is attached again after step 106 is executed. That the control flow shown in this figure, it is the output voltage _{V B} of the main battery 12 detected by the voltage sensor 24 is not a _{V B ≒ 0 [V] (} 108), the value of the contact control signal CONT is L value (110) and that the start signal ST is on (112). When all of these conditions are satisfied, the vehicle ECU 20 changes the value of the contact control signal CONT from the L value to the H value (114). In response, the relays A and B are turned on, for example, at the timing shown in FIG. Therefore, in this embodiment, even if the safety plug 18 is removed after the relays A and B are turned off according to the control flow shown in FIG. 2, the vehicle operator once turns off the start signal ST, and again turns off the start signal ST. The relays A and B are turned on at a predetermined timing without repeating the procedure of turning them on, so that a highly usable device can be obtained.
[0025]
Further, in this embodiment, the state of the safety plug 18 is detected by the determination of the output voltage V _B across the voltage of the main battery 12, i.e. by the voltage sensor 24. Output voltage V _B of the main battery 12, the not shown is provided conventionally for charge and discharge control of the control and the main battery 12 from the inverter 14 are common, thus, functions special according to this embodiment This can be realized by only partially changing the control procedure of the vehicle ECU 20 without adding a hardware configuration. Therefore, the device of this embodiment is easy to realize, and can achieve the effect of further improving safety.
[0026]
FIG. 4 shows the configuration of an electric vehicle according to a second embodiment of the present invention. As shown in this figure, in the present embodiment, the configuration of the safety plug 26 is different from the configuration of the safety plug 18 in the first embodiment. The safety plug 26 has a contact 30 for grounding the wiring 28 pulled up to +5 [V]. The wiring 28 is connected to the vehicle ECU 20 via the buffer 32. Vehicle ECU 20 inputs the output of buffer 32 as plug state signal PLG. The plug state signal PLG has an L value when the safety plug 26 is mounted, and has an H value when the safety plug 26 has been removed. That is, when the safety plug 26 is mounted, the wiring 28 is grounded via the contact 30, so that the plug state signal PLG has the L value. The potential becomes +5 [V], and the plug state signal PLG accordingly becomes H level.
[0027]
5 and 6 show a control flow of the vehicle ECU 20 in the present embodiment. In particular, the control flow shown in FIG. 5 corresponds to the control flow of FIG. 2 in the first embodiment, and the control flow shown in FIG. 6 corresponds to the control flow shown in FIG. 3, respectively. Steps 104A and 108A are executed instead of steps 104 and 108.
[0028]
In step 104A and 108A, instead of the detection value _{V B} of the output voltage in the first embodiment, the state of the safety plug 26 with a plug status signal PLG is determined. That is, in steps 104A and 108A, it is determined whether or not the value of the plug state signal PLG is the H value. If the value is the H value, the safety plug 26 is removed, and if the value is the L value. Each is determined to be mounted.
[0029]
Therefore, also in this embodiment, the same effects as those of the first embodiment can be obtained. Further, this effect can be realized by an additional configuration of the safety plug 26, that is, the contact 30, and a small change in hardware is sufficient.
[0030]
In the control flows shown in FIGS. 2 and 5, when it is determined that the safety plug 18 or 26 has been removed, the value of the contact control signal CONT is changed to the L value in step 106, and the relays A and B was both off. However, only B of relays A and B may be turned off. That is, when the relay A is on and the B is off, the charging of the capacitor C by the discharging current of the main battery 12 is performed via the resistor R. The current value can be limited. In that case, in step 114 shown in FIG. 3 or FIG. 6, it is sufficient to turn on only relay B.
[0031]
Furthermore, the present invention is not limited to controlling the connection between the main battery 12 and the inverter 14. In other words, if the device to be connected to the main battery 12 has a property that a relatively large current can flow immediately after connection to the main battery 12, the connection between the device and the main battery 12 is The invention can be applied. In addition, the configuration of the relays A and B, the configuration of other parts of the junction box 22, or the configuration of the safety plug 18 or 26 is not limited.
[0032]
【The invention's effect】
As described above, according to the present invention, at least the second contact is opened when the maintenance plug is detached, so that the discharge current of the battery is reduced even when the maintenance plug is attached again. A large current can be prevented, and a safe and highly usable electric vehicle can be obtained without damage to the maintenance plug due to spark generation.
[0033]
Further, according to the present invention, when the maintenance plug is attached after the connection opening control unit opens the first and second contacts, the first and second contacts are closed at a predetermined timing. The second contact is closed at a predetermined timing when the maintenance plug is attached after the connection opening control means opens only the second contact among the first and second contacts. Thus, the power of the battery can be supplied to the device to be driven without the need for the vehicle operator to once turn off the start signal and turn it on again after the maintenance plug is attached again.
[0034]
According to the present invention, the above-described detecting means can be further realized by an additional configuration of a maintenance plug, or can be realized by using a voltage sensor or the like. Therefore, it is not necessary to make a major hardware modification to the device, and it is possible to obtain a device that can be easily implemented at an early stage.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first embodiment.
FIG. 2 is a diagram showing a control flow of this embodiment.
FIG. 3 is a diagram showing a control flow of this embodiment.
FIG. 4 is a block diagram showing a configuration of a second embodiment.
FIG. 5 is a diagram showing a control flow of this embodiment.
FIG. 6 is a diagram showing a control flow of this embodiment.
FIG. 7 is a block diagram showing a configuration of a conventional example.
FIG. 8 is a diagram showing a control flow of this conventional example.
FIG. 9 is a diagram showing a problem of the conventional example.
[Explanation of symbols]
10 motor, 12 main battery, 14 inverter, 18, 26 safety plug, 20 vehicle ECU, 22 junction box, 24 voltage sensor, A, B relay, R resistance, C capacitor.

Claims (5)

A first contact provided to open and close a connection between a battery and a capacitor mounted between the battery-side terminals on the electric vehicle, and a current limiter connected in series to the first contact; A resistor, a second contact provided in parallel with the first contact and the current limiting resistor provided to open and close the connection between the battery and the driven device, and closing the connection between the battery and the driven device. Closing timing control means for controlling the opening and closing timing of the first and second contacts so that the current flowing through the device to be driven is limited by the current limiting resistor, when the maintenance plug is attached to the battery. A battery connection control device for an electric vehicle that controls connection between a battery that outputs only a DC voltage and a device to be driven driven by the voltage output from the battery. Te,
Detecting means for detecting the state of attachment / detachment of the maintenance plug to / from the battery;
Connection opening control means for opening at least the second contact when the maintenance plug is removed;
A battery connection control device for an electric vehicle, comprising: The battery connection control device for an electric vehicle according to claim 1,
The connection opening control means is means for opening the first and second contacts when the maintenance plug is removed,
When a maintenance plug is attached after the connection opening control unit opens the first and second contacts, the connection release control unit closes the first and second contacts at a predetermined timing. Battery connection control device for electric vehicles. The battery connection control device for an electric vehicle according to claim 1,
The connection opening control means is means for opening only the second contact of the first and second contacts when the maintenance plug is removed,
Battery connection for an electric vehicle, comprising: connection recovery control means for closing the second contact at a predetermined timing when a maintenance plug is attached after the connection opening control means opens the second contact. Control device. 2. The battery connection control device for an electric vehicle according to claim 1, wherein the detecting means is provided with a third contact provided so as to be integrally attached to and detached from the maintenance plug, and the maintenance plug is detached when the third contact is opened. And a means for determining that the battery is mounted when the vehicle is closed. 2. The battery connection control device for an electric vehicle according to claim 1, wherein the detecting means determines that the maintenance plug has been removed when the output voltage of the battery is lower than a predetermined value, and the means detects the output voltage of the battery. A battery connection control device for an electric vehicle, comprising:

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