JP2020156202A - Vehicle charging system - Google Patents

Abstract

To provide a vehicle charging system that can subject a vehicle to quick charging using a plurality of chargers, and can increase use efficiency of each of the chargers.SOLUTION: A vehicle charging system 10 comprises: an external power supply device 30 having a plurality of chargers A to C; and connection means 40 that, for a vehicle 20 having a power storage device 22 and a plurality of charging ports 24A to 24C, electrically connects the plurality of charging ports and the plurality of chargers, respectively. The external power supply device 30 includes communication means 38A to 38C provided for the respective chargers and acquiring charging rate information of a vehicle power storage device connected by the connection means, and a charging control unit 32 that, based on the information acquired by the communication means, in a case where the charging rate of the power storage device electrically connected to the plurality of chargers becomes more than or equal to a specified value, performs current drooping control of sequentially reducing a charging current value from each of the chargers connected to the power storage device one by one to zero.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle charging system, and more particularly to a charging system for a vehicle having a plurality of charging ports.

In recent years, there has been an increase in demand for vehicles (hereinafter, also referred to as electric vehicles) equipped with a power storage device as a drive source, such as EV (Electric Vehicle) and PHV (Plug-in Hybrid Electric Vehicle).

In electric vehicles, it takes longer to charge the power storage device than the refueling time of gasoline vehicles. Therefore, a technique for quick charging has been developed to shorten the time required for charging.

In order to charge the power storage device in a short time, it is necessary to increase the charging current value to the power storage device, for example, by applying a high voltage on the external power supply side serving as the charger. In a power storage device having a low charging rate, charging is performed rapidly by passing a high current from the charger. In addition, when the charging rate of the power storage device increases and the terminal voltage rises, the current value flowing through the power storage device decreases, and at the end of charging, the internal resistance of the power storage device rapidly increases and the terminal voltage rises. As a result, the current value is significantly reduced.

With the spread of electric vehicles, the development of charging equipment capable of passing a high current at a time by a charger having one high voltage power supply is progressing. However, such a charger has a problem that the construction cost of the charging facility increases because the component cost is high and the charger itself becomes expensive. Further, as the speed of charging progresses, it is necessary to change the standard and develop the corresponding technology on the vehicle side as well, so that there is a problem that the development cost and the product cost increase.

In view of these circumstances, a technology has been developed that enables quick charging using existing equipment.

For example, Patent Document 1 discloses a vehicle charging device in which a vehicle is provided with a plurality of charging ports and can be charged from each charging port at the same time. This vehicle charging device is a device capable of performing quick charging using a commercial power source used in ordinary households, and charges each of a plurality of charging ports provided in the vehicle via a charging cable. By connecting an external commercial power source that serves as a device, a plurality of chargers are connected in parallel, and the current value is increased by passing the current flowing through each charging cable to the power storage device.

Japanese Unexamined Patent Publication No. 2014-155420

Like the device described in Patent Document 1, one charger is connected to each of a plurality of charging ports provided in the vehicle, and a structure capable of charging by passing an electric current from each of the chargers connected in parallel is provided. Therefore, not only in general households, but also in charging equipment installed in public facilities such as service areas, for example, quick charging can be performed by utilizing conventional equipment without newly developing and installing large-scale dedicated equipment. Is possible.

However, in public charging facilities, it is required not only to be able to quickly charge vehicles, but also to efficiently charge a large number of vehicles simultaneously and efficiently at the time of congestion. Therefore, it has been required to develop a charging facility capable of efficiently charging a plurality of vehicles by improving the usage efficiency of each charger while performing quick charging using a plurality of chargers.

The present invention has been made in view of the above problems, and it is possible to perform quick charging using a plurality of chargers for one vehicle and to improve the usage efficiency of each charger. The purpose is to provide a vehicle charging system.

In order to achieve the above object, the invention according to claim 1 is for a vehicle having an external power supply device having a plurality of chargers, a power storage device, and a plurality of charging ports for supplying electric energy to the power storage device. On the other hand, in a vehicle charging system that includes connecting means for electrically connecting the plurality of charging ports and the plurality of chargers, respectively, and capable of simultaneously supplying electric energy from the plurality of chargers to the power storage device. The external power supply device is provided in each charger, and the communication means for acquiring the charge rate information of the power storage device of the vehicle connected by the connection means, and the plurality of communication means based on the information acquired by the communication means. When the charging rate of the power storage device electrically connected to the charger exceeds a predetermined value, the current value from each charger connected to the power storage device is sequentially reduced to zero one by one. It is characterized by being provided with a charge control unit that controls the current drooping.

According to this configuration, a plurality of charging ports provided in one vehicle and a plurality of chargers of an external power supply device are electrically connected to each other, and electric energy is supplied from the plurality of chargers at the same time. , The power storage device of the vehicle can be charged quickly. Further, when the charging rate of the power storage device exceeds a predetermined value and the current value from each charger decreases, the current value of each charger connected to the power storage device is reduced to zero one by one. Of the multiple chargers that are electrically connected to one power storage device by the current droop control that reduces the current value until it becomes zero, the charger that has reached zero current value and is no longer energized is connected to another vehicle. It can be used to charge a power storage device. In addition, the charging efficiency of the remaining chargers connected to the power storage device can be maintained high. As a result, the usage efficiency of each charger of the external power supply device can be improved.

Further, according to the second aspect of the present invention, in the vehicle charging system according to the first aspect, the external power supply device includes a temperature sensor that detects the temperature of each charger, and the current droop control controls a plurality of charging. When the charging rate of the power storage device electrically connected to the charger exceeds a predetermined value, the current value is reduced in order from the charger having the highest temperature based on the detection result of the temperature sensor. ..

According to this configuration, when a plurality of chargers are used at the same time, the difference in the external environment for each charger causes a difference in temperature between the chargers, and the internal resistance becomes large in the charger having a high temperature. Charging efficiency may be reduced. By reducing the current of the charger, which may have a reduced charging efficiency, before other chargers, the charging efficiency can be kept high when quick charging is performed. Further, by lowering the current of the high temperature charger first, this charger can be cooled before other chargers.

Further, in the invention according to claim 3, in the vehicle charging system according to claim 1, the charge control unit acquires cumulative usage time information from each charger, and the current droop control is performed by a plurality of chargers. When the charge rate of the power storage device electrically connected to the battery exceeds a predetermined value, the current value is reduced in order from the charger having the longest cumulative usage time based on the cumulative usage time information acquired by the communication means. It is characterized by letting it.

According to this configuration, it is possible to equalize the cumulative usage time of a plurality of chargers included in the external power supply device. As a result, it is possible to prevent a specific charger from deteriorating over time and significantly reducing the charging efficiency, and to maintain a high overall charging efficiency of the charging system.

Further, according to the fourth aspect of the present invention, in the vehicle charging system according to the third aspect, the external power supply device includes a temperature sensor that detects the temperature of each charger, and the current droop control controls a plurality of charging. When the charging rate of the power storage device electrically connected to the charger exceeds a predetermined value, the current value is reduced in order from the charger with the longest cumulative usage time, and the difference in the cumulative usage time is less than the predetermined value. In the case of, the current value is reduced in order from the charger having the highest temperature based on the detection result of the temperature sensor.

According to this configuration, the cumulative usage time of a plurality of chargers provided in the external power supply device can be made uniform, and when the difference in the cumulative usage time between the chargers used at the same time is small, the temperature becomes high. By reducing the current of the high charger first, the charging efficiency at the time of quick charging can be kept high.

According to the vehicle charging system according to the present invention, one vehicle can be quickly charged by using a plurality of chargers, and the usage efficiency of each charger can be improved.

The block diagram explaining the structure of the charging system which is one Embodiment of this invention. The flowchart which shows the procedure of control of each charger by a charge control part. The graph which shows the time change of the current of each charger connected to a power storage device.

Hereinafter, the charging system according to the present invention will be described. FIG. 1 is a block diagram illustrating a configuration of a charging system according to an embodiment of the present invention.

The charging system 10 includes, for example, an external power supply device 30 in a power storage device 22 mounted on an electric vehicle (hereinafter, also simply referred to as “vehicle”) 20 such as an EV (Electric Vehicle) or a PHV (Plug-in Hybrid Electric Vehicle). It is a system for charging from the vehicle, and includes a vehicle 20, an external power supply device 30 having a plurality of chargers A to C, and a connection cable (connection means) 40 for electrically connecting these. In FIG. 1, only the electric line 21 on the positive electrode side of the charging electric circuit connecting the chargers A to C and the power storage device 22 is shown by a solid line, and the description of the electric line on the negative electrode side is omitted.

The vehicle 20 includes a power storage device 22 as a drive source, a plurality of charging connectors 24A, 24B, 24C, a battery control unit 26 for controlling the battery state of the power storage device 22, and a vehicle-side communication unit (communication means). 28 and.

The power storage device 22 is a device that stores electrical energy that serves as a drive source for the vehicle 20, and for example, a lead battery, a lithium ion battery, a nickel hydrogen battery, a lithium ion battery, or the like can be used.

The charging ports 24A to 24C form a connector for taking in electric energy from the external power supply device 30, and each charging port 24A to 24C has the same structure in the present embodiment. In the present embodiment, the number of charging ports is set to three, but the number is not limited to this and may be two or more. The charging ports 24A to 24C are connected in parallel in the positive electrode side line 21 and the negative electrode side electric line of the charging circuit.

The positive electrode side electric line 21 connecting the charging ports 24A, 24B, 24C and the power storage device 22 is provided with backflow prevention devices 25A, 25B, 25C, respectively, to prevent backflow of current. The backflow prevention devices 25A to 25 can be configured by, for example, a diode.

The battery control unit 26 is connected to the power storage device 22 and monitors the state of the power storage device 22 to control charging / discharging of the power storage device 22. The battery control unit 26 can be composed of a CPU, which is a central processing unit, a ROM, a RAM, and a microcomputer having an internal bus connecting them. The state of the power storage device 22 can be monitored, for example, by detecting the voltage of the power storage device 22 or the current flowing through the power storage device 22 by a voltage sensor or a current sensor (not shown) mounted on the power storage device 22.

Further, as shown by the broken line in FIG. 1, the battery control unit 26 is connected to each of the charging ports 24A to 24C via the vehicle-side communication unit 28, and the information of the power storage device 22 is provided via the connection cable 40. For example, the charging rate of the power storage device 22 and identification information from other power storage devices) can be transmitted to the charging side control unit 32 of the external power supply device 30.

In the power storage device 22, the maximum value of the charging voltage is limited by the battery control unit 26, and in the final charging state where the charging rate is high, the charging current flowing through the power storage device 22 according to the current drooping characteristic set in the battery control unit 26. The value is controlled.

The external power supply device 30 includes a plurality of chargers A, B, and C for supplying electric energy to the power storage device 22, and a charge control unit 32 for controlling the charging state of each of the chargers A to C. The chargers A to C may be configured to have the same standard, or may be configured to have different standards so that their respective charging states can be appropriately controlled. In the present embodiment, the number of chargers is set to three, but the number is not limited to this and may be two or more.

The chargers A to C are connected to the connector portions 34A, 34B, 34C to which the connection cable 40 is connected, the temperature sensors 36A, 36B, 36C for detecting the temperature of the chargers A, B, and C, and the charging side communication. Units (communication means) 38A, 38B, 38C are provided. In this embodiment, the temperature sensors 36A to 36C are mounted on the connector portions 34A to 34C.

The charging side communication units 38A to 38C transmit information about the power storage device 22 of the vehicle 20 connected to the connector units 34A to 34C via the connection cable 40 to the charging control unit 32. In this embodiment, the vehicle-side communication unit 28, the connection cable 40, and the charging-side communication units 38A to 38C are used to wire-wirely transmit information about the power storage device 22 to the charging control unit 32. The communication method is not limited to wired, and may be wireless.

The charge control unit 32 is connected to each of the chargers A to C, monitors the state of each of the chargers A to C22, for example, voltage, current, temperature of the chargers A to C22, cumulative usage time, etc., and monitors each charger. Controls the voltage and current values of A to C22. The charge control unit 32 can be composed of a CPU, which is a central processing unit, a ROM, a RAM, and a microcomputer having an internal bus connecting them. The state of the chargers A to C can be detected by, for example, a voltage sensor or a current sensor (not shown) mounted on the chargers A to C. Further, the temperature can be detected by the temperature sensors 36A to 36C, and the cumulative usage time can be calculated by the timer built in the charge control unit 32. can do.

The connection cable 40 has a vehicle-side connector 42 that can electrically connect the power storage device 22 of the vehicle 20 and the chargers A to C, and can be connected to the charging ports 24A to 24C at one end. A charging side connector 43 that can be connected to the connector portions 34A to 34C is provided at the other end.

Further, each charging port 24A, 24B, 24C and each connector portion 34A, 34B, 34 has a built-in connection detection sensor (not shown) for detecting whether or not the connectors 42, 43 of the connection cable 40 are connected. ing. The battery control unit 26 and the charge control unit 32 can detect the connection state of the connection cable 40 and the connection state of the charging ports 24A to 24C and the chargers A to C based on the detection result of the connection detection sensor. Is.

In the charging system 10 described above, the vehicle-side connector 42 of the connection cable 40 is connected to the charging ports 24A to 24C of the vehicle 20, and the charging-side connector 43 of the connection cable 40 is connected to the connector portions 34A to 34C of the chargers A to C. Then, by setting the charging state of the chargers A to C in the external power supply device 30 to the ON state, the power storage device 22 mounted on the vehicle 20 can be charged. Further, by changing the number of chargers A to C connected to the power storage device 22, it is possible to switch between quick charging and low speed charging.

For example, a plurality of charging ports 24A to 24C provided in the vehicle 20 and a plurality of charging ports A to C of the external power supply device 30 are electrically connected via a connection cable 40 to be connected in parallel. It is possible to increase the value of the current flowing through the power storage device 22 by simultaneously passing a current from the chargers A to C. As a result, quick charging that shortens the charging time can be performed. Further, when the number of chargers that can be used in the external power supply device 30 is small, such as when the vehicle is congested, the number of chargers connected to the power storage device 22 is reduced, for example, only one charger A is used. By connecting and charging, the current value flowing through the power storage device 22 can be reduced to perform low-speed charging.

When charging the power storage device 22, a large current can flow from the external power supply device 30 side when the charging rate is low. On the other hand, as the charging rate increases and the terminal voltage of the power storage device 22 increases, the flowing current decreases. When the external power supply device 30 detects that the charging side communication units 38A to 38C are in the final charging state in which the charging rate of the power storage devices 22 connected to the chargers A to C is equal to or higher than a predetermined value S, the communication unit 30 Each of the chargers A to C is controlled so that the current value flowing from the chargers A to C to the power storage device 22 decreases according to the current drooping characteristic of the power storage device 22 acquired via the above.

In the charging system 10 of the present embodiment, when one power storage device 22 is rapidly charged by using two or more chargers at the same time and the power storage device 22 reaches the end of charging state, The charge control unit 32 performs current droop control in which the currents of the plurality of chargers connected to the power storage device 22 are sequentially reduced one by one until the current value becomes zero. The order of the chargers A to C for lowering the current value is determined according to the selection criteria set in advance in the charge control unit 32, and in the present embodiment, the temperature of the chargers A to C detected by the temperature sensors 36A to 36C is determined. The current value is decreased in descending order.

Next, charging control when charging the power storage device 22 of one vehicle 20 using the charging system 10 described above will be described. FIG. 2 is a flowchart showing a procedure for controlling each charger by the charge control unit 32. In this flowchart, as an example, a flow when three chargers A to C are used at the same time for quick charging is shown.

When any of the chargers A to C is electrically connected to at least one of the charging ports 24A to 24C of the vehicle 20 via the connection cable 40, the charging control unit 32 is connected. Information about the power storage device 22, that is, identification information of the power storage device 22, charging rate, current drooping characteristic, and the like are acquired via the charging side communication units 38A to 38C of the charger (step S11).

Next, it is determined whether the number of chargers A to C connected to the power storage device 22 is one for low-speed charging or two or more for fast charging (step S12).

When the charge control unit 32 determines that the charging is quick (step S12: Yes), each charging is performed by a plurality of chargers (here, three chargers A to C) connected in parallel to the power storage device 22. Rapid charging control is performed to control the currents from the chargers A to C to the power storage device 22 to have substantially the same value (step S13). This control is performed until the charge rate of the power storage device 22 reaches a predetermined value S set in the battery control unit 26.

When the charge rate of the power storage device 22 becomes equal to or higher than the predetermined value S by the quick charge control (step S14: Yes), the charge control unit 32 detects the chargers A to C based on the detection results of the temperature sensors 36A to 36C. The current value of the charger having the highest temperature (hereinafter referred to as the first charger) is lowered according to the current drooping characteristic of the power storage device 22 (step S15). When the current value of the first charger becomes zero, the first charger is turned off and the electrical connection to the power storage device 22 is cut off (step S16).

When the current value of the first charger becomes zero, the charge control unit 32 sets the current value of the charger having the highest temperature detected by the temperature sensor (hereinafter referred to as the second charger) among the remaining chargers. It is reduced according to the current drooping characteristic of the power storage device 22 (step S17). When the current value of the second charger becomes zero, the second charger is turned off and the electrical connection to the power storage device 22 is cut off (step S18).

When the current value of the second charger becomes zero, the charge control unit 32 lowers the current value of the remaining one charger (hereinafter referred to as the third charger) according to the current drooping characteristic of the power storage device 22. (Step S19). When the current value of the third charger becomes zero, the third charger is turned off, the electrical connection to the power storage device 22 is cut off (step S20), and the charging control is terminated.

If it is determined in step S12 that the charging is low speed (step S12: No), the low speed charging control is performed to charge the power storage device 22 by one connected charger (step S22). In the low-speed charging control, when the charging rate becomes equal to or higher than a predetermined value, the current value of the connected charger is lowered according to the current drooping characteristic, and then the charger is turned off.

FIG. 3 is a graph showing the time change of the current value of each of the chargers A to C when the power storage device 22 is rapidly charged by using the three chargers A to C at the same time. FIG. 3 shows an example in which the charger A is the first charger, the charger B is the second charger, and the charger C is the third charger.

At the start of rapid charging, substantially the same current I ₁ flows through each of the chargers A to C, and 3I ₁ by adding the current values of the three chargers A to C flows through the power storage device 22. Elapsed charging time, the charging rate of the storage device 22 becomes a predetermined value S in time t _1, the charge control unit 32 reduces the current value of the first charger A. Thereafter, when the current value of the first charger A becomes zero in time t _2, the charge control unit 32 reduces the current value of the second charger B. Thereafter, when the current value of the second charger B becomes zero in time t _4, the charge control unit 32 reduces the current value of the third charging device C. The relationship of time t in the graph is t ₁ <t ₂ ≤ t ₃ <t ₄ ≤ t ₅ <t ₆ .

As described above, in the charging system 10 of the present embodiment, the plurality of charging ports 24A to 24B provided in the vehicle 20 and the plurality of chargers A to C of the external power supply device 30 are connected to each other by using the connection cable 40. By electrically connecting and supplying electric energy from a plurality of chargers A to C at the same time, the power storage device 22 can be quickly charged.

Further, when the charging rate of the power storage device 22 becomes a predetermined value S or more and the current droop control for the power storage device 22 is performed, the current values of the connected chargers A to C are sequentially reduced to zero one by one. Of the plurality of chargers A to C electrically connected to one power storage device 22, the first charger A whose current value becomes zero and the energization is completed is the other. It can be connected to the charging port of the vehicle and used to charge the power storage device of this vehicle. In this way, while charging the vehicle 20, the first charger A and the second charger B whose current value becomes zero and the energization is completed can be used for charging another vehicle. Therefore, it is possible to efficiently charge a large number of vehicles at the same time at the time of congestion. Further, the charging efficiency of the remaining charger C connected to the vehicle 20 can be kept high at the end of charging. Thereby, the usage efficiency of each of the chargers A to C of the external power supply device 30 can be improved. In particular, as in the present embodiment, the current value of any one of the plurality of chargers A to C is lowered, and after this current value becomes zero, the current value of the next charger is set. By lowering the value, the previous charger can be quickly turned off and used for charging another vehicle, so that the usage efficiency can be improved.

Further, the charging efficiency can be kept high by determining the order in which the current values are lowered according to the temperatures of the chargers A to C. Specifically, when a plurality of chargers A to C are used at the same time in quick charging, the difference in the external environment for each of the chargers A to C (for example, how the sunlight hits and the heat generating part of the vehicle 20 are in the vicinity. There is a temperature difference between the chargers A to C, etc.). In a charger having a high temperature (for example, the first charger A), the internal resistance may increase and the charging efficiency may decrease, and the current of such a charger may be applied to other chargers B and C. By lowering it before, the charging efficiency can be kept high. Further, by lowering the current value of the charger A having a high temperature first, it is possible to suppress the overheating of the charger A and cool the charger A before the other chargers B and C.

The order of the chargers for reducing the current selected by the charge control unit 32 is not limited to those described above, and the settings can be changed as appropriate.

For example, in the initial setting, the order of the chargers A to C for lowering the current value may be determined in advance.

Further, depending on the cumulative usage time of each charger, the current value may be reduced first from the one with the longest cumulative usage time. As an example, when the cumulative usage time of the charger B is the longest and the cumulative usage time of the charger A is the shortest, the first charger B, the second charger C, and the third charger A are in that order. Performs current droop control to reduce the current value. If the charging system 10 performs current droop control in which the plurality of chargers A to C are sequentially lowered one by one by quick charging, the usage time of each of the chargers A to C becomes uneven, but the subsequent quick charging In the above, by performing the order of the chargers A to C for lowering the current value in order from the one having the longest cumulative usage time, the cumulative usage time is made uniform. As a result, it is possible to prevent a specific charger from deteriorating over time and significantly lowering the charging efficiency, and to maintain a high overall charging efficiency of the charging system 10.

Further, the order in which the current values are reduced may be determined based on the cumulative usage time and temperature of each of the chargers A to C. For example, when the cumulative usage time of each charger A to C is calculated and the difference between the cumulative usage time is large, specifically, when the difference between the cumulative usage time is greater than or equal to a predetermined value, the cumulative usage time is large. The current value is reduced in order from the one. On the other hand, when the difference in cumulative usage time is small, specifically, when the difference in cumulative usage time between the two (or three) chargers is less than a predetermined value, the temperature sensors 36A to 36C detect it. Based on the temperature, the current value is controlled to decrease in order from the charger with the highest temperature. By performing such control, the cumulative usage time of the plurality of chargers A to C included in the external power supply device 30 can be made uniform, and the cumulative usage time of the chargers A to C used at the same time can be made uniform. When the difference between the two is small, the charging efficiency can be kept high by first lowering the current value of the charger having a high temperature.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

For example, in the current droop control in quick charging, among a plurality of chargers connected to one power storage device, the current value of the first charger is first lowered, and then the current value of the first charger is changed. The current of the second charger may be reduced before it reaches zero. In such a case, control is performed so that the current value of the first charger becomes zero before the second charger. Even in such current droop control, the first charger whose current value becomes zero can be used for charging another vehicle.

10 Charging system 20 Vehicle 22 Charging device 24A, 24B, 24C Charging port 25A, 25B, 25C Backflow prevention device 26 Battery control unit 28 Vehicle side communication unit 30 External power supply device 32 Charging control unit 34A, 34B, 34C Connector unit 36A, 36B , 36C Temperature sensor 38A, 38B, 38C Charger side communication unit 40 Connection cable A, B, C Charger

Claims (4)

An external power supply with multiple chargers and
A vehicle having a power storage device and a plurality of charging ports for supplying electric energy to the power storage device is provided with a connection means for electrically connecting the plurality of charging ports and the plurality of chargers, respectively. In a vehicle charging system capable of simultaneously supplying electrical energy to the power storage device from the plurality of chargers.
The external power supply device
A communication means provided in each charger to acquire charge rate information of the power storage device of the vehicle connected by the connection means, and
Based on the information acquired by the communication means, when the charge rate of the power storage device electrically connected to the plurality of chargers becomes a predetermined value or more, from each charger connected to the power storage device. A vehicle charging system characterized by being provided with a charging control unit that controls current drooping to reduce the current values of the above one by one until it becomes zero. The external power supply device includes a temperature sensor that detects the temperature of each charger.
In the current droop control, when the charging rate of the power storage device electrically connected to the plurality of chargers exceeds a predetermined value, the current is sequentially applied from the charger having the highest temperature based on the detection result of the temperature sensor. The vehicle charging system according to claim 1, wherein the value is reduced. The charge control unit acquires cumulative usage time information from each charger and obtains information on the cumulative usage time.
In the current droop control, when the charge rate of the power storage device electrically connected to the plurality of chargers exceeds a predetermined value, the cumulative usage time is based on the cumulative usage time information acquired by the communication means. The vehicle charging system according to claim 1, wherein the current value is reduced in order from the most chargers. The external power supply device includes a temperature sensor that detects the temperature of each charger.
In the current droop control, when the charging rate of the power storage device electrically connected to the plurality of chargers exceeds a predetermined value, the current value is reduced in order from the charger having the longest cumulative usage time, and the current value is reduced. The vehicle charging system according to claim 3, wherein when the difference in cumulative usage time is less than a predetermined value, the current value is reduced in order from the charger having the highest temperature based on the detection result of the temperature sensor. ..

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