Vehicle, vehicle control device, and charging system

A vehicle includes: a first power line configured to connect an inlet and an energy storage device via a power conversion device; a second power line configured to connect the inlet and the energy storage device without via the power conversion device; a first relay configured to switch between a first electrically connected state in which the second power line is electrically connected and a first electrically disconnected state in which the second power line is electrically disconnected; and a first control device. The first control device is configured to switch the first relay to the first electrically disconnected state when a voltage that can be supplied from the external power supply is lower than a voltage range in which the energy storage device can be charged.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2022-018813 filed on Feb. 9, 2022, incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to vehicles whose in-vehicle energy storage device can be charged using an external power supply, vehicle control devices, and charging systems.

2. Description of Related Art

In some vehicles such as battery electric vehicles, in-vehicle energy storage devices can be charged using an external power supply. Such vehicles are sometimes equipped with a power conversion device. The power conversion device is, for example, a converter that converts power received from an external power supply to power for charging the in-vehicle energy storage device. The energy storage device can be charged by stepping up or stepping down the voltage of the power from the external power supply using such a power conversion device. Alternatively, the energy storage device can be charged by supplying the power from the external power supply directly to the energy storage device without using a power conversion device.

For example, WO 2008/041418 discloses a vehicle equipped with a plurality of energy storage devices (batteries) and a plurality of boost converters. In this vehicle, at least one of the energy storage devices of the vehicle is charged using the power from an external power supply and at least one of the boost converters.

SUMMARY

The voltage of energy storage devices that are mounted on vehicles has been more and more increased. However, some external power supplies are not compatible with high-voltage energy storage devices. Therefore, vehicles are sometimes equipped with a power conversion device. The power conversion device boosts the voltage from an external power supply when the voltage that can be supplied from the external power supply to the vehicle is not high enough. Therefore, when an external power supply is compatible with high-voltage energy storage devices, the energy storage device can be charged by supplying the power from the external power supply to the energy storage device without via the power conversion device. When an external power supply is not compatible with high-voltage energy storage devices, the energy storage device can be charged by boosting the voltage from the external power supply to a voltage that can charge the energy storage device by the power conversion device and then supplying the resultant power to the energy storage device. Such an operation is implemented by, for example, switching the power transmission path using a switching device such as relay. However, if the relay is switched inappropriately, it may cause an inrush current etc.

The present disclosure provides a vehicle, vehicle control device, and charging system that can appropriately switch to a power transmission path corresponding to the voltage that can be output from an external power supply.

A vehicle according to one aspect of the present disclosure includes: an inlet configured to be connected to an external power supply outside the vehicle; a power conversion device configured to be connected to the inlet; an energy storage device configured to be charged with power supplied via the inlet; a first power line configured to connect the inlet and the energy storage device via the power conversion device; a second power line configured to connect the inlet and the energy storage device without via the power conversion device; a first relay configured to switch between a first electrically connected state in which the second power line is electrically connected and a first electrically disconnected state in which the second power line is electrically disconnected; and a first control device configured to control the first relay. The first control device is configured to switch the first relay to the first electrically disconnected state when a voltage that is able to be supplied from the external power supply is lower than a voltage range in which the energy storage device is able to be charged.

With this configuration, the first relay is in the first electrically disconnected state when the voltage that is able to be supplied from the external power supply is lower than the voltage range in which the energy storage device is able to be charged. Hereinafter, the voltage range in which the energy storage device is able to be charged is sometimes simply referred to as “voltage range.” A current can thus be restrained from flowing from the energy storage device to the external power supply. Therefore, it is possible to appropriately switch to the power transmission path corresponding to the voltage that is able to be output from the external power supply.

In one embodiment, the vehicle may further include a second control device different from the first control device. The second control device may be configured to acquire information on the voltage that is able to be supplied from the external power supply, and may be configured to, when the voltage that is able to be supplied from the external power supply as included in the acquired information is lower than the voltage range, switch the first relay to the first electrically disconnected state regardless of a command for the first relay generated in the first control device.

With this configuration, the first relay to be in the first electrically disconnected state even when a normal command signal cannot be generated in the first control device.

In one embodiment, the vehicle may further include a second relay configured to switch between a second electrically connected state in which the first power line is electrically connected and a second electrically disconnected state in which the first power line is electrically disconnected. The first control device may be configured to switch the first relay to the first electrically connected state and switch the second relay to the second electrically disconnected state when the voltage that is able to be supplied from the external power supply is within the voltage range.

With this configuration, the first relay is in the first electrically connected state and the second relay is in the second electrically disconnected state when the voltage that is able to be supplied from the external power supply is within the voltage range. Therefore, it is possible to charge the energy storage device by supplying the power supplied to the inlet directly to the energy storage device without via the power conversion device.

In one embodiment, the vehicle may further include a detection device that detects a voltage at the inlet. The second control device may be configured to, when the voltage that is able to be supplied from the external power supply is lower than the voltage range and the voltage at the inlet is higher than a threshold, switch the first relay to the first electrically disconnected state and the second relay to the second electrically disconnected state regardless of a command for the first relay and the second relay generated in the first control device.

With this configuration, when the voltage that is able to be supplied from the external power supply is lower than the voltage range and the voltage at the inlet is higher than the threshold, the first relay is in the first electrically disconnected state and the second relay is in the second electrically disconnected state regardless of a command for the first relay and the second relay generated in the first control device. A current can thus be restrained from flowing from the vehicle side to the external power supply side.

A vehicle control device according to another aspect of the present disclosure is mounted on a vehicle. The vehicle includes: an inlet configured to be connected to an external power supply outside the vehicle; a power conversion device configured to be connected to the inlet; an energy storage device configured to be charged with power supplied via the inlet; a first power line configured to connect the inlet and the energy storage device via the power conversion device; a second power line configured to connect the inlet and the energy storage device without via the power conversion device; and a first relay configured to switch between a first electrically connected state in which the second power line is electrically connected and a second electrically disconnected state in which the second power line is electrically disconnected. The vehicle control device includes: an acquisition unit configured to acquire a voltage that is able to be supplied from the external power supply; and a control unit configured to control the first relay in such a manner that the first relay switches to the first electrically disconnected state when the voltage that is able to be supplied from the external power supply is lower than a voltage range in which the energy storage device is able to be charged.

A charging system according to still another aspect of the present disclosure includes a vehicle, and an external power supply outside the vehicle. The vehicle includes: an inlet configured to be connected to the external power supply; a power conversion device configured to be connected to the inlet; an energy storage device configured to be charged with power supplied via the inlet; a first power line configured to connect the inlet and the energy storage device via the power conversion device; a second power line configured to connect the inlet and the energy storage device without via the power conversion device; and a first relay configured to switch between a first electrically connected state in which the second power line is electrically connected and a first electrically disconnected state in which the second power line is electrically disconnected. The external power supply includes a control device configured to control the first relay. The control device is configured to switch the first relay to the first electrically disconnected state when a voltage that is able to be supplied from the external power supply is lower than a voltage range in which the energy storage device is able to be charged.

According to the present disclosure, it is possible to provide a vehicle, vehicle control device, and charging system that appropriately switch to a power transmission path corresponding to the voltage that can be output from an external power supply.

DETAILED DESCRIPTION OF EMBODIMENTS

An embodiment of the present disclosure will be described in detail below with reference to the drawings. The same or corresponding parts are denoted by the same signs throughout the drawings, and description thereof will not be repeated.

FIG.1schematically shows an example of a configuration of a charging system1according to an embodiment. Referring toFIG.1, the charging system1includes a vehicle2and a charging station800. The vehicle2includes a battery pack10, a buck-boost unit40, an inlet60, an electric vehicle-electronic control unit (EV-ECU)100, a charging integrated ECU300, a first load unit500, and a second load unit600. The vehicle2is, for example, an electrified vehicle such as battery electric vehicle or hybrid electric vehicle.

The battery pack10includes an energy storage device12, a system main relay (SMR) unit20, a battery ECU200, a battery voltage sensor110, and a battery current sensor112.

The EV-ECU100includes a processor such as central processing unit (CPU), a memory such as read-only memory (ROM) and random access memory (RAM), and an input and output port for inputting and outputting various signals (none of which is shown). The EV-ECU100manages the operating state of an in-vehicle electrical device such as SMR unit20, based on signals from various sensors and programs stored in the memory. The EV-ECU100outputs, for example, a permission-prohibition signal DCEN1to the charging integrated ECU300. The permission-prohibition signal DCEN1indicates whether the operation of a first relay52according to a first command for the first relay52generated in the charging integrated ECU300is permitted or prohibited. The EV-ECU100also outputs, for example, a permission-prohibition signal DCEN2to the charging integrated ECU300. The permission-prohibition signal DCEN2indicates whether the operation of a second relay54and a third relay56according to a second command for the second relay54and a third command for the third relay56generated in the charging integrated ECU300is permitted or prohibited.

The energy storage device12is a rechargeable direct current (DC) power supply. The energy storage device12includes, for example, a secondary battery such as nickel metal hydride battery or lithium-ion battery with a liquid or solid electrolyte. The energy storage device12may be a capacitor such as electric double layer capacitor. The energy storage device12supplies power to an electrical device included in the first load unit500. The energy storage device12may be charged with the power supplied from the buck-boost unit40or the first load unit500. The energy storage device12is, for example, an assembled battery composed of a plurality of battery cells. In the present embodiment, the energy storage device12includes, for example, an energy storage device having a voltage higher than 500 V.

The SMR unit20is electrically connected between the energy storage device12and the buck-boost unit40and first load unit500. Commands to close and open the SMR unit20are send from the EV-ECU100. The SMR unit20includes, for example, a first SMR22, a second SMR24, a third SMR26, and a precharge resistor28. The commands to close and open the SMR unit20include commands to close and open the first SMR22, commands to close and open the second SMR24, and commands to close and open the third SMR26.

The first SMR22is provided on a first positive electrode line PL1. The first positive electrode line PL1includes a power line connecting a positive terminal of the inlet60and a positive terminal of the energy storage device12. The second SMR24is provided on a first negative electrode line NL1. The first negative electrode line NL1includes a power line connecting a negative terminal of the inlet60and a negative terminal of the energy storage device12. The third SMR26is provided on a second negative electrode line NL2. The second negative electrode line NL2is connected in parallel with the second SMR24provided on the first negative electrode line NL1. The precharge resistor28is connected in series with the third SMR26on the second negative electrode line NL2.

The battery ECU200includes a processor such as CPU, a memory such as ROM and RAM, and an input and output port for inputting and outputting various signals (none of which is shown). The battery ECU200manages the charge state of the energy storage device12, based on signals received from the battery voltage sensor110and the battery current sensor112and programs stored in the memory.

The battery voltage sensor110detects a battery voltage VB of the energy storage device12and sends a signal indicating the detected battery voltage VB to the battery ECU200. The battery voltage sensor110is provided in parallel with the energy storage device12between, for example, the first positive electrode line PL1and the first negative electrode line NL1. The battery voltage sensor110detects the voltage between the first positive electrode line PL1and the first negative electrode line NL1as the battery voltage VB.

The battery current sensor112detects a battery current IB flowing through the energy storage device12and sends a signal indicating the detected battery current D3to the battery ECU200. The battery current sensor112is connected in series with the second SMR24, and detects a current flowing through the energy storage device12as the battery current IB.

The battery ECU200calculates the state of charge (SOC) of the energy storage device12using the battery current IB and the battery voltage VB. Various methods such as current integration (Coulomb counting) method and open-circuit voltage (OCV) estimation method can be used to calculate the SOC. The battery ECU200sends information on the calculated SOC to the EV-ECU100and the charging integrated ECU300.

The first load unit500includes an electrical device that operates at a predetermined first voltage (e.g., a voltage higher than 500 V). The first load unit500includes, for example, a power control unit (PCU) and a motor generator (MG) (neither of which is shown). The PCU converts power between the battery pack10and the MG. The PCU includes, for example, an inverter that drives the MG with the power supplied from the battery pack10, and a converter that adjusts the level of a direct current (DC) voltage to be supplied to the inverter (neither of which is shown).

For example, the MG is driven by the inverter of the PCU when the vehicle2is traveling. The power of the MG is transmitted to drive wheels.

The inlet60is provided in an exterior portion of the vehicle2. The buck-boost unit40is connected to the inlet60. For example, the buck-boost unit40steps up or steps down the voltage of the power supplied to the inlet60and supplies the power with the resultant voltage to the first load unit500and the second load unit600.

The inlet60has such a shape that a connector802of the charging station800that is an external power supply can be attached to the inlet60. When the connector802is attached to the inlet60, a built-in contact of the inlet60comes into contact with a built-in contact of the connector802, so that the inlet60is electrically connected to the connector802. The connector802is connected to the charging station800via a cable etc.FIG.1shows, by way of example, the connector802attached to the inlet60.

The charging station800is, for example, a charging station that can perform charging with an upper limit of the charging voltage being 500 V or less.

The buck-boost unit40includes a buck-boost converter42, a charging relay unit50, a first voltage sensor150, a second voltage sensor152, a third voltage sensor154, and a buck-boost ECU400.

The buck-boost converter42boosts the voltage of the power supplied from the charging station800and supplies the resultant power to the battery pack10and the first load unit500, according to a control signal from the buck-boost ECU400. The second load unit600is connected to power lines branching from the first positive electrode line PL1and the first negative electrode line NL1between the buck-boost converter42and the charging relay unit50. For example, the power supplied from the charging station800may be supplied directly to the second load unit600via the inlet60and the charging relay unit50. The second load unit600includes, for example, an electrical device (e.g., PCU and MG) that operates at a predetermined second voltage (e.g., voltage of 500 V or less).

The buck-boost ECU400includes a processor such as CPU, a memory such as ROM and RAM, and an input and output port for inputting and outputting various signals (none of which is shown). The buck-boost ECU400controls the buck-boost converter42based on signals received from the first voltage sensor150and the second voltage sensor152and programs stored in the memory.

The first voltage sensor150detects a voltage VL to be input to the buck-boost converter42(i.e., a voltage between the first positive electrode line PL1and the first negative electrode line NL1between the charging relay unit50and the buck-boost converter42), and sends a signal indicating the detected voltage VL to the buck-boost ECU400.

The second voltage sensor152detects a voltage VH output from the buck-boost converter42(i.e., a voltage between the first positive electrode line PL1and the first negative electrode line NL1between the buck-boost converter42and the battery pack10), and sends a signal indicating the detected voltage VH to the buck-boost ECU400.

The charging relay unit50is electrically connected between the inlet60and the buck-boost converter42. Commands to close and open the charging relay unit50are sent from the charging integrated ECU300. The charging relay unit50includes the first relay52, the second relay54, and the third relay56.

The first relay52is provided on a second positive electrode line PL2. One end of the second positive electrode line PL2is connected to a position between the inlet60and the second relay54that will be described below on the first positive electrode line PL1. The other end of the second positive electrode line PL2is connected to a position between the buck-boost converter42and the battery pack10on the first positive electrode line PL1. The second relay54is provided at a position between the inlet60and the buck-boost converter42on the first positive electrode line PL1. The third relay56is provided at a position between the inlet60and the buck-boost converter42on the first negative electrode line NL1.

Each of the first relay52, the second relay54, and the third relay56operates according to a control signal from the charging integrated ECU300. That is, the commands to close and open the charging relay unit50include commands to close and open the first relay52, commands to close and open the second relay54, and commands to close and open the third relay56.

The charging integrated ECU300includes: a microcomputer composed of a processor such as CPU, a memory such as ROM and RAM, and an input and output port for inputting and outputting various signals; and a plurality of logic circuits that outputs drive signals for the first relay52, the second relay54, and the third relay56using signals output from the microcomputer and signals input from the EV-ECU100. The microcomputer and the logic circuits will be described later.

When the connector802is attached to the inlet60, the charging integrated ECU300controls at least one of the three relays, the first relay52, the second relay54, and the third relay56, based on information indicating whether the connector802is attached to the inlet60, information on the power supplied from the charging station800that is acquired from the charging station800, signals received from the third voltage sensor154, and programs stored in the memory.

The third voltage sensor154detects a voltage VDC between a connection point of the first positive electrode line PL1with the one end of the second positive electrode line PL2and the first negative electrode line NL1. The third voltage sensor154sends a signal indicating the detected voltage VDC to the charging integrated ECU300.

For example, the inlet60is provided with a detection circuit or detection sensor (not shown) that detects whether the connector802is attached to the inlet60. When the connector802is attached to the inlet60, the detection circuit or detection sensor outputs a signal indicating that the connector802is attached to the inlet60to the charging integrated ECU300. The charging integrated ECU300determines that the connector802is attached to the inlet60, when this signal is input to the charging integrated ECU300as the information indicating whether the connector802is attached to the inlet60.

The charging integrated ECU300also controls at least one of the three relays, the first relay52, the second relay54, and the third relay56, using the information on the power supplied from the charging station800. For example, the charging integrated ECU300may acquire the information on the power supplied from the charging station800by wireless communication with the charging station800, or may acquire the information on the power supplied from the charging station800by wired communication using a power line and a communication line.

The voltage of the energy storage device12that is mounted on the vehicle2with the above configuration has been more and more increased. However, the charging station800may not be compatible with such high-voltage energy storage devices. Therefore, the vehicle2is equipped with such a buck-boost converter42as described above. When the charging station800is compatible with high-voltage energy storage devices, the energy storage device12can be charged by supplying power from the charging station800to the energy storage device12without via the buck-boost converter42. When the charging station800is not compatible with high-voltage energy storage devices, the energy storage device12can be charged by boosting the voltage from the charging station800to a voltage that can charge the energy storage device12by the buck-boost converter42and supplying the resultant power to the energy storage device12. Such an operation is implemented by switching the power transmission path using the above charging relay unit50. However, if the relay is switched inappropriately, it may cause an inrush current etc.

Therefore, in the present embodiment, when the voltage supplied from the charging station800is lower than the voltage range in which the energy storage device12can be charged, the charging integrated ECU300opens the first relay52to electrically disconnect the second positive electrode line PL2(a first electrically disconnected state).

A current can thus be restrained from flowing from the energy storage device12to the charging station800. Therefore, it is possible to appropriately switch to the power transmission path corresponding to the voltage that can be output from the charging station800.

Moreover, when the voltage that can be supplied from the charging station800as included in information on the voltage that can be supplied from the charging station800is lower than the voltage range, the EV-ECU100electrically disconnects the first relay52(the first electrically disconnected state) regardless of the command for the first relay52generated in the charging integrated ECU300.

The first relay52can thus be electrically disconnected even when a normal command signal cannot be generated in the charging integrated ECU300.

Hereinafter, a detailed configuration of the charging integrated ECU300will be described with reference toFIG.2.FIG.2shows an example of a detailed configuration of the charging integrated ECU300.

As shown inFIG.2, the charging integrated ECU300includes a microcomputer302, a first logical conjunction (AND) circuit304, a second AND circuit306, and a third AND circuit308.

The microcomputer302outputs a first command for the first relay52to the first AND circuit304. The microcomputer302also outputs a second command for the second relay54to the second AND circuit306. The microcomputer302also outputs a third command for the third relay56to the third AND circuit308. Each of the first command, the second command, and the third command includes, for example, either an OFF signal for outputting “0” corresponding to a command to switch to the electrically disconnected state or an ON signal for outputting “1” corresponding to a command to switch to the electrically connected state.

The microcomputer302determines the state (either the electrically connected state or the electrically disconnected state) of each of the first relay52, the second relay54, and the third relay56, based on the information on the voltage that can be supplied from the charging station800.

The microcomputer302outputs, as a command signal, a signal indicating an ON state (e.g., “1”) to a logic circuit corresponding to a relay to be electrically connected (hereinafter referred to as “relay to be rendered conductive”). The microcomputer302outputs, as a command signal, a signal indicating an OFF state (e.g., “0”) to a logic circuit corresponding to a relay to be electrically disconnected (hereinafter referred to as “relay to be rendered non-conductive”).

For example, when the microcomputer302determines the first relay52to be a relay to be rendered conductive and determines the second relay54and the third relay56to be relays to be rendered non-conductive, the microcomputer302outputs an ON signal to the first AND circuit304and outputs an OFF signal to each of the second AND circuit306and the third AND circuit308.

For example, when the microcomputer302determines the first relay52to be a relay to be rendered non-conductive and determines the second relay54and the third relay56to be relays to be rendered conductive, the microcomputer302outputs an OFF signal to the first AND circuit304and outputs an ON signal to each of the second AND circuit306and the third AND circuit308.

Not only the first command but also the permission-prohibition signal DCEN1from the EV-ECU100are input to the first AND circuit304. Not only the second command but also the permission-prohibition signal DCEN2from the EV-ECU100are input to the second AND circuit306. Not only the third command but also the permission-prohibition signal DCEN2from the EV-ECU100are input to the third AND circuit308.

The first AND circuit304outputs to the first relay52a drive signal DFR1generated using the first command from the microcomputer302and the permission-prohibition signal DCEN1from the EV-ECU100.

Specifically, the first AND circuit304outputs a signal corresponding to a logical conjunction of the first command from the microcomputer302and the permission-prohibition signal DCEN1from the EV-ECU100to the first relay52as the drive signal DFR1.

For example, when the permission-prohibition signal DCEN1is a signal indicating permission (e.g., a signal corresponding to “1”), the first AND circuit304outputs the first command from the microcomputer302to the first relay52as the drive signal DFR1. That is, when an ON signal is output from the microcomputer302as the first command, an ON signal is output from the first AND circuit304to the first relay52as the drive signal DFR1. When an OFF signal is output from the microcomputer302as the first command, an OFF signal is output from the first AND circuit304to the first relay52as the drive signal DFR1.

On the other hand, for example, when the permission-prohibition signal DCEN1is a signal indicating prohibition (e.g., a signal corresponding to “0”), an OFF signal is output from the first AND circuit304to the first relay52as the drive signal DFR1regardless of whether the first command from the microcomputer302is an ON signal or an OFF signal.

The second AND circuit306outputs to the second relay54a drive signal DFR2generated using the second command from the microcomputer302and the permission-prohibition signal DCEN2from the EV-ECU100.

Specifically, the second AND circuit306outputs a signal corresponding to a logical conjunction of the second command from the microcomputer302and the permission-prohibition signal DCEN2from the EV-ECU100to the second relay54as the drive signal DFR2.

For example, when the permission-prohibition signal DCEN2is a signal indicating permission (e.g., a signal corresponding to “1”), the second AND circuit306outputs the second command from the microcomputer302to the second relay54as the drive signal DFR2. That is, when an ON signal is output from the microcomputer302as the second command, an ON signal is output from the second AND circuit306to the second relay54as the drive signal DFR2.

On the other hand, for example, when the permission-prohibition signal DCEN2is a signal indicating prohibition (e.g., a signal corresponding to “0”), an OFF signal is output from the second AND circuit306to the second relay54as the drive signal DFR2regardless of whether the second command from the microcomputer302is an ON signal or an OFF signal.

The third AND circuit308outputs to the third relay56a drive signal DFR3generated using the third command from the microcomputer302and the permission-prohibition signal DCEN2from the EV-ECU100.

Specifically, the third AND circuit308outputs a signal corresponding to a logical conjunction of the third command from the microcomputer302and the permission-prohibition signal DCEN2from the EV-ECU100to the third relay56as the drive signal DFR3.

The operation of the third AND circuit308is different from the operation of the second AND circuit306illustrated above in that the third command is input to the third AND circuit308instead of the second command and that the drive signal DFR3is output from the third AND circuit308instead of the drive signal DFR2. Since the configuration and operation of the third AND circuit308are otherwise similar to those of the second AND circuit306, detailed description thereof will not be repeated.

For example, when the connector802is attached to the inlet60, the microcomputer302determines a relay to be rendered conductive and a relay to be rendered non-conductive by using the information on the voltage that can be supplied from the charging station800.

For example, when the voltage that can be supplied from the charging station800is a voltage within the voltage range in which the energy storage device12can be charged, the microcomputer302determines the first relay52and the third relay56to be relays to be rendered conductive and determines the second relay54to be a relay to be rendered non-conductive. Therefore, the microcomputer302outputs an ON signal to the first AND circuit304and the third AND circuit308as the first command and the third command, respectively, and outputs an OFF signal to the second AND circuit306as the second command.

On the other hand, for example, when the voltage that can be supplied from the charging station800is a voltage lower than the voltage range in which the energy storage device12can be charged, the microcomputer302determines the second relay54and the third relay56to be relays to be rendered conductive and determines the first relay52to be a relay to be rendered non-conductive. Therefore, the microcomputer302outputs an ON signal to the second AND circuit306and the third AND circuit308as the second command and the third command, respectively, and outputs an OFF signal to the first AND circuit304as the first command.

For example, when the SOC of the energy storage device12acquired from the battery ECU200is within a range corresponding to the fully charged state, the microcomputer302outputs an OFF signal to the first AND circuit304, the second AND circuit306, and the third AND circuit308as the first command, the second command, and the third command, respectively.

In the present embodiment, as described above, the EV-ECU100in the vehicle2having the above configuration outputs an OFF signal as the permission-prohibition signal DCEN1when the voltage that can be supplied from the charging station800is lower than the voltage range in which the energy storage device12can be charged.

Hereinafter, an example of a process that is performed by the EV-ECU100will be described with reference toFIG.3.FIG.3is a flowchart showing an example of a process that is performed by the EV-ECU100. A series of steps shown in the flowchart is repeatedly performed by the EV-ECU100in predetermined control cycles.

In step100(hereinafter the term “step” is abbreviated as “S”), the EV-ECU100determines whether the voltage that can be output from the charging station800is lower than a predetermined voltage. The EV-ECU100determines whether the voltage that can be output from the charging station800is lower than the predetermined voltage by using, for example, information on charging power acquired from the charging station800. Since the method for acquiring the information on charging power is as described above, detailed description thereof will not be repeated. The predetermined voltage is, for example, a voltage of about 500 V. When it is determined that the voltage that can be output from the charging station800is lower than the predetermined voltage (YES in S100), the process proceeds to S102.

In S102, the EV-ECU100outputs an OFF signal as the permission-prohibition signal DCEN1. The process then proceeds to S104.

In S104, the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN2. The process then ends. When it is determined that the voltage that can be output from the charging station800is equal to or higher than the predetermined voltage (NO in S100), the process proceeds to S106.

In S106, the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN1. The process then proceeds to S108.

In S108, the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN2. The process then ends.

An example of the operation of the EV-ECU100and the charging integrated ECU300according to the present embodiment based on the above structure and flowchart will be described.

For example, it is herein assumed that the connector802of the charging station800is attached to the inlet60of the vehicle2in a stopped state. It is also assumed that the upper limit of the voltage that can be output from the charging station800is lower than the predetermined voltage.

When the connector802of the charging station800is attached to the inlet60, information on charging power is acquired from the charging station800, and it is determined whether the voltage that can be output from the charging station800as included in the acquired information is lower than the predetermined voltage (S100).

When the voltage that can be output from the charging station800is lower than the predetermined voltage (YES in S100), an OFF signal is output to the charging integrated ECU300as the permission-prohibition signal DCEN1(S102), and an ON signal is output to the charging integrated ECU300as the permission-prohibition signal DCEN2(S104).

For example, when the connector802is attached to the inlet60and the voltage that can be output from the charging station800is lower than the predetermined voltage, the microcomputer302of the charging integrated ECU300determines the second relay54and the third relay56to be relays to be rendered conductive, and determines the first relay52to be a relay to be rendered non-conductive. Therefore, the microcomputer302outputs an ON signal to the second AND circuit306and the third AND circuit308as the second command and the third command, respectively, and outputs an OFF signal to the first AND circuit304as the first command.

When an ON signal is input from the EV-ECU100to the second AND circuit306and the third AND circuit308as the permission-prohibition signal DCEN2, an ON signal is output from the second AND circuit306and the third AND circuit308to the second relay54and the third relay56as the drive signals DFR2, DFR3, respectively, and an OFF signal is output from the first AND circuit304to the first relay52as the drive signal DFR1. At this time, the second positive electrode line PL2is electrically disconnected, and the first positive electrode line PL1is electrically connected. Therefore, the power from the charging station800is supplied to the energy storage device12via the buck-boost converter42.

An OFF signal is input from the EV-ECU100to the first AND circuit304as the permission-prohibition signal DCEN1. Therefore, even when an ON signal is input to the first AND circuit304as the first command due to an abnormality in the microcomputer302, an OFF signal is output from the first AND circuit304as the drive signal DFR1. Therefore, the first relay52is suppressed from being in an electrically connected state (a first electrically connected state).

When the voltage that can be output from the charging station800is equal to or higher than the predetermined voltage (NO in S100), an ON signal is output to the charging integrated ECU300as the permission-prohibition signal DCEN1(S106), and an ON signal is output to the charging integrated ECU300as the permission-prohibition signal DCEN2(S108).

For example, when the connector802is attached to the inlet60and the voltage that can be output from the charging station800is equal to or higher than the predetermined voltage, the microcomputer302of the charging integrated ECU300determines the first relay52and the third relay56to be relays to be rendered conductive, and determines the second relay54to be a relay to be rendered non-conductive. Therefore, the microcomputer302outputs an ON signal to the first AND circuit304and the third AND circuit308as the first command and the third command, respectively, and outputs an OFF signal to the second AND circuit306as the second command.

When an ON signal is input from the EV-ECU100to the first AND circuit304as the permission-prohibition signal DCEN1and an ON signal is input from the EV-ECU100to the second AND circuit306and the third AND circuit308as the permission-prohibition signal DCEN2, an ON signal is output from the first AND circuit304and the third AND circuit308to the first relay52and the third relay56as the drive signals DFR1, DFR3, respectively, and an OFF signal is output from the second AND circuit306to the second relay54as the drive signal DFR2. At this time, the second positive electrode line PL2is electrically connected, and the connection point of the first positive electrode line PL1with the one end of the second positive electrode line PL2is electrically disconnected from a connection point of the first positive electrode line PL1with the other end of the second positive electrode line PL2. Therefore, the power from the charging station800is supplied to the energy storage device12without via the buck-boost converter42.

As described above, in the vehicle2according to the present embodiment, when the voltage that can be supplied from the charging station800that is an external power supply is lower than the voltage range in which the energy storage device12can be charged, the first relay52is electrically disconnected. A current can therefore be restrained from flowing from the energy storage device12to the charging station800. In particular, an OFF signal is input to the first AND circuit304as the permission-prohibition signal DCEN1. Therefore, even when an ON signal is input to the first AND circuit304as the first command due to an abnormality in the microcomputer302, an OFF signal is output from the first AND circuit304. Therefore, the first relay52can be electrically disconnected. Accordingly, it is possible to provide a vehicle, vehicle control device, and charging system that appropriately switch to a power transmission path corresponding to the voltage that can be output from an external power supply.

Hereinafter, modifications will be described. In the above embodiment, it is described that the permission-prohibition signals DCEN1, DCEN2are set based on whether the voltage that can be output from the charging station800is lower than the predetermined voltage. For example, the permission-prohibition signals DCEN1, DCEN2may be set based not only on the voltage that can be output from the charging station800but also on whether the voltage VDC detected by the third voltage sensor154is higher than a threshold.

FIG.4schematically shows an example of a configuration of the vehicle2according to a modification. The charging integrated ECU300shown inFIG.4is different from the charging integrated ECU300shown inFIG.1in that the detection result from the third voltage sensor154is output not only to the charging integrated ECU300but also to the EV-ECU100. The configuration is otherwise similar to the configuration of the vehicle2shown inFIG.1except for the case described below. Therefore, detailed description thereof will not be repeated.

As shown inFIG.4, in this modification, the third voltage sensor154is configured to output a signal indicating the detected voltage VDC to each of the charging integrated ECU300and the EV-ECU100. The charging integrated ECU300may output the voltage VDC acquired from the third voltage sensor154to the EV-ECU100.

Hereinafter, an example of a process that is performed by the EV-ECU100will be described with reference toFIG.5.FIG.5is a flowchart showing an example of a process that is performed by the EV-ECU100according to the modification. A series of steps shown in the flowchart is repeatedly performed by the EV-ECU100in predetermined control cycles.

In S200, the EV-ECU100determines whether the voltage that can be output from the charging station800is lower than a predetermined voltage. Since the method for determining whether the voltage that can be output from the charging station800is lower than the predetermined voltage is as described above, detailed description thereof will not be repeated. When it is determined that the voltage that can be output from the charging station800is lower than the predetermined voltage (YES in S200), the process proceeds to S202.

In S202, the EV-ECU100determines whether the voltage VDC detected by the third voltage sensor154is higher than a threshold Va. The threshold Va is herein described as the same value as the predetermined voltage. However, the threshold Va may be any value as long as it can be determined that the voltage on the inlet60side is higher than at least the output voltage of the charging station800. The threshold Va is not particularly limited to the same value as the predetermined voltage. When it is determined that the voltage VDC is higher than the threshold Va (YES in S202), the process proceeds to S204.

In S204, the EV-ECU100outputs an OFF signal as the permission-prohibition signal DCEN1. The process then proceeds to S206.

In S206, the EV-ECU100outputs an OFF signal as the permission-prohibition signal DCEN2. The process then ends.

In S208, the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN1. The process then proceeds to S210.

In S210, the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN2. The process then ends. When it is determined that the voltage VDC is equal to or lower than the threshold Va (NO in S202), the process proceeds to S212.

In S212, the EV-ECU100outputs an OFF signal as the permission-prohibition signal DCEN1. The process then proceeds to S214.

In S214, the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN2. The process then ends.

An example of the operation of the EV-ECU100and the charging integrated ECU300according to this modification based on the above structure and flowchart will be described.

For example, it is herein assumed that the connector802of the charging station800is attached to the inlet60of the vehicle2in a stopped state. It is also assumed that the voltage that can be output from the charging station800is lower than the predetermined voltage.

When the connector802of the charging station800is attached to the inlet60, information on charging power is acquired from the charging station800, and it is determined whether the voltage that can be output from the charging station800as included in the acquired information is lower than the predetermined voltage (S200).

When the voltage that can be output from the charging station800is lower than the predetermined voltage (YES in S200) and the voltage VDC is equal to or lower than the threshold Va (NO in S202), an OFF signal is output to the charging integrated ECU300as the permission-prohibition signal DCEN1(S212), and an ON signal is output to the charging integrated ECU300as the permission-prohibition signal DCEN2(S214).

Therefore, an OFF signal is output from the first AND circuit304to the first relay52as the drive signal DFR1, an ON signal is output from the second AND circuit306to the second relay54as the drive signal DFR2, and an ON signal is output from the third AND circuit308to the third relay56as the drive signal DFR3. At this time, the second positive electrode line PL2is electrically disconnected, and the first positive electrode line PL1is electrically connected. Therefore, the power from the charging station800is supplied to the energy storage device12via the buck-boost converter42.

An OFF signal is input from the EV-ECU100to the first AND circuit304as the permission-prohibition signal DCEN1. Therefore, even when an ON signal is input to the first AND circuit304as the first command due to an abnormality in the microcomputer302, an OFF signal is output from the first AND circuit304as the drive signal DFR1. Therefore, the first relay52is less likely to be electrically connected.

On the other hand, when an abnormality occurs such as the first relay52being fixed to the ON state or the voltage of the energy storage device12being supplied to the inlet60due to an abnormality in the buck-boost converter42, and the voltage VDC becomes higher than the threshold Va due to such an abnormality (YES in S202), an OFF signal is output as the permission-prohibition signal DCEN1, and an OFF signal is output as the permission-prohibition signal DCEN2.

As a result, even when an ON signal is output as the second command and the third command, an OFF signal is output from the first AND circuit304to the first relay52as the drive signal DFR1, an OFF signal is output from the second AND circuit306to the second relay54as the drive signal DFR2, and an OFF signal is output from the third AND circuit308to the third relay56as the drive signal DFR3. At this time, all of the first positive electrode line PL1, the second positive electrode line PL2, and the first negative electrode line NL1are electrically disconnected. A current can therefore be restrained from flowing from the energy storage device12to the charging station800.

In the above embodiment, the configuration in which one relay is provided on the second positive electrode line PL2is described as an example. However, two relays may be provided on the second positive electrode line PL2.

FIG.6schematically shows an example of a configuration of the vehicle2according to another modification. The vehicle2shown inFIG.6is different from the vehicle2shown inFIG.1in that a fourth relay58is further provided on the second positive electrode line PL2, in addition to the first relay52. The configuration is otherwise similar to the configuration of the vehicle2shown inFIG.1except for the case described below. Therefore, detailed description thereof will not be repeated.

As shown inFIG.6, in this modification, the first relay52and the fourth relay58that are connected in series with each other are provided on the second positive electrode line PL2. For example, the charging integrated ECU300may be configured to output the drive signal DFR1from the first AND circuit306to the first relay52and output a drive signal DFR4from the first AND circuit306to the fourth relay58. Alternatively, the charging integrated ECU300may further include a fourth AND circuit (not shown) that outputs a logical conjunction of the permission-prohibition signal DCEN1and the first command from the microcomputer302, and may be configured to output the drive signal DFR4from the fourth AND circuit to the fourth relay58.

With this configuration, even when an ON signal is unintentionally output as the first command due to an abnormality in the microcomputer302as described above, the electrically disconnected state of the first relay52and the fourth relay58can be maintained as the permission-prohibition signal DCEN1is an OFF signal. Moreover, even when one of the two relays, the first relay52and the fourth relay58, is fixed to the ON state, the second positive electrode line PL2can be electrically disconnected using the relay that is not fixed to the ON state.

Furthermore, for example, the fixed state of at least one of the four relays, the first relay52, the second relay54, the third relay56, and the fourth relay58, can be detected by switching the first relay52, the second relay54, the third relay56, and the fourth relay58between the electrically connected state (the first electrically connected state, a second electrically connected state, a third electrically connected state, and a fourth electrically connected state) and the electrically disconnected state (the first electrically disconnected state, a second electrically disconnected state, a third electrically disconnected state, and a fourth electrically disconnected state) after charging is completed.

FIG.7is a flowchart showing an example of a process that is performed by the microcomputer302of the charging integrated ECU300according to this modification. A series of steps shown in this flowchart is performed by the microcomputer302when an execution condition such as after charging is satisfied. For convenience of explanation, it is herein assumed that the EV-ECU100outputs an ON signal as the permission-prohibition signal DCEN1and the permission-prohibition signal DCEN2.

In S300, the microcomputer302sets the first relay52, the second relay54, the third relay56, and the fourth relay58to their initial state. That is, the microcomputer302outputs an ON signal as the first command, the third command, and the fourth command, and outputs an OFF signal as the second command.

In S302, the microcomputer302sets the third relay56to the OFF state. That is, the microcomputer302outputs an OFF signal as the third command.

In S304, the microcomputer302determines whether the voltage VDC is lower than a predetermined value A. The predetermined value A is, for example, a predetermined value that is lower than the voltage of the energy storage device12. When it is determined that the voltage VDC is lower than the predetermined value A (YES in S304), the process proceeds to S306.

In S306, the microcomputer302sets the first relay52to the OFF state. That is, the microcomputer302outputs an OFF signal as the first command. The process then proceeds to S310. When it is determined that the voltage VDC is not lower than the predetermined value A (NO in S304), the process proceeds to S308.

In S308, the microcomputer302determines that the third relay56is fixed to the ON state. The microcomputer302sets, for example, a failure determination flag indicating that the third relay56is fixed to the ON state. The process then proceeds to S306.

In S310, the microcomputer302sets the third relay56to the ON state. The process then proceeds to S312.

In S312, the microcomputer302determines whether the voltage VDC is lower than a predetermined value B. The predetermined value B is, for example, a predetermined value that is lower than the voltage of the energy storage device12. The predetermined value B may be the same value as the predetermined value A, or may be a different value from the predetermined value A. When it is determined that the voltage VDC is lower than the predetermined value B (YES in S312), the process proceeds to S314.

In S314, the microcomputer302sets the fourth relay58to the OFF state. That is, the microcomputer302outputs an OFF signal as the fourth command. The process then proceeds to S318. When it is determined that the voltage VDC is not lower than the predetermined value B (NO in S312), the process proceeds to S316.

In S316, the microcomputer302determines that the first relay52is fixed to the ON state. The microcomputer302sets, for example, a failure determination flag indicating that the first relay52is fixed to the ON state. The process then proceeds to S314.

In S318, the microcomputer302sets the first relay52to the ON state. The process then proceeds to S320.

In S320, the microcomputer302determines whether the voltage VDC is lower than a predetermined value C. The predetermined value C is, for example, a predetermined value that is lower than the voltage of the energy storage device12. The predetermined value C may be the same value as either or both of the predetermined value A and the predetermined value B, or may be a different value from both the predetermined value A and the predetermined value B. When it is determined that the voltage VDC is lower than the predetermined value C (YES in S320), the process proceeds to S322.

In S322, the microcomputer302sets the third relay56to the OFF state. The process then proceeds to S326. When it is determined that the voltage VDC is not lower than the predetermined value C (NO in S320), the process proceeds to S324.

In S324, the microcomputer302determines that the fourth relay58is fixed to the ON state. The microcomputer302sets, for example, a failure determination flag indicating that the fourth relay58is fixed to the ON state. The process then proceeds to S322.

In S326, the microcomputer302sets the first relay52to the OFF state. The process then proceeds to S328.

In S328, the microcomputer302determines whether the voltage VDC is lower than a predetermined value D. The predetermined value D is, for example, a predetermined value that is lower than the voltage of the energy storage device12. The predetermined value D may be the same value as at least one of the three predetermined values, the predetermined value A, the predetermined value B, and the predetermined value C, or may be a different value from all of the predetermined value A, the predetermined value B, and the predetermined value C. When it is determined that the voltage VDC is lower than the predetermined value D (YES in S328), the process proceeds to S330.

In S330, the microcomputer302outputs the determination results. For example, the microcomputer302may output the determination results, such as information indicating that repair is necessary and information on a failure location based on the states of the various failure determination flags, to a display device etc. When it is determined that the voltage VDC is not lower than the predetermined value D (NO in S328), the process proceeds to S332.

In S332, the microcomputer302determines that the first relay52and the third relay56of both electrodes are fixed to the ON state. The process then proceeds to S330.

The operation of the charging integrated ECU300according to this modification based on the above structure and flowchart will be described.

For example, it is herein assumed that charging of the energy storage device12is completed. At this time, the third relay56is set to the OFF state (S302) after being set to its initial state (S300). When the voltage VDC is not lower than the predetermined value A (NO in S304), it is determined that the third relay56is fixed to the ON state (S308).

Thereafter, or when it is determined that the voltage VDC is lower than the predetermined value A (YES in S304), the first relay52is set to the OFF state (S306), and the third relay56is set to the ON state (S310). When it is determined that the voltage VDC is not lower than the predetermined value B (NO in S312), it is determined that the first relay52is fixed to the ON state (S316).

Thereafter, or when it is determined that the voltage VDC is lower than the predetermined value B (YES in S312), the fourth relay58is set to the OFF state (S314), and the first relay52is set to the ON state (S318).

When the voltage VDC is not lower than the predetermined value C (NO in S320), it is determined that the fourth relay58is fixed to the ON state (S324).

Thereafter, or when it is determined that the voltage VDC is lower than the predetermined value C (YES in S320), the third relay56is set to the OFF state (S322), and the first relay52is set to the OFF state (S326).

At this time, when the voltage VDC is not lower than the predetermined value D (NO in S328), it is determined that both the first relay52and the third relay56are fixed to the ON state (S332).

Thereafter, or when the voltage VDC is lower than the predetermined value D (YES in S328), the determination results are output (S330).

In this way, whether each relay is fixed to the ON state can be accurately determined.

In the above embodiment, it is described that the permission-prohibition signals DCEN1, DCEN2generated in the EV-ECU100are output to the charging integrated ECU300. However, for example, the permission-prohibition signals DCEN1, DCEN2may be generated in a control device804(FIG.1) included in the charging station800, and the generated permission-prohibition signals DCEN1, DCEN2may be input to the charging integrated ECU300. In some embodiments, in the case where the permission-prohibition signals DCEN1, DCEN2generated in the EV-ECU100are output to the charging integrated ECU300, the control device804may not be provided in the charging station800.

The above modifications may be wholly or partially combined as appropriate. The embodiment disclosed herein should be considered as illustrative, not restrictive, in all respects. The scope of the present disclosure is defined by the claims rather than by the above description, and is intended to include all modifications that fall within the meaning and scope equivalent to those of the claims.