Vehicle, charging system, and method of charging a vehicle

Abstract

Prior to receiving a message from the charging device that can be used to determine the vehicle's charging method, the vehicle determines its own charging method. [Solution] The vehicle 1 includes a battery pack 15 that is charged using DC power from a charging device 2 as charging power, a voltage sensor 13 that detects the charging voltage of the charging power, a switching device 14 configured to switch between charging methods with different charging voltages, and a vehicle controller 16 that determines the charging method. The vehicle controller 16 obtains the insulation diagnostic voltage applied by the charging device 2 from the voltage sensor 13 and determines the charging method based on the insulation diagnostic voltage.

Description

Technical Field

[0001] The present disclosure relates to a vehicle, a charging system, and a method for charging a vehicle.

Background Art

[0002] Japanese Patent No. 7110159 (Patent Document 1) discloses a power supply system mounted on a vehicle. The power supply system includes a first battery, a second battery, and a switching unit. The switching unit can switch between a series circuit that connects the first battery and the second battery in series and a parallel circuit that connects the first battery and the second battery in parallel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Among vehicles capable of so-called external charging with electric power supplied from a charging device provided outside the vehicle, some are configured to be able to switch charging methods with different charging voltages in order to shorten the charging time. As an example, a certain vehicle is configured to be able to switch between a charging method with a high voltage (for example, 400V) and a charging method with an ultra-high voltage (for example, 800V).

[0005] The inventors have found that the following problems may arise with such vehicles. Generally, in external charging, multiple messages are exchanged between the vehicle and the charging device prior to actual power supply / charging. These multiple messages include a message sent from the charging device to the vehicle indicating the maximum output voltage of the charging device. It is also conceivable that the vehicle receives this message from the charging device and determines the vehicle's charging method according to the maximum output voltage of the charging device.

[0006] However, some charging devices terminate the normal communication sequence and stop supplying power to the vehicle if the vehicle changes its charging method after the message has been sent. To ensure more reliable external charging of the vehicle, it may be preferable for the vehicle to determine its charging method before receiving a message from the charging device that can be used to determine the charging method.

[0007] This disclosure is made to solve the above-mentioned problems, and one of the purposes of this disclosure is to enable a vehicle to determine its charging method prior to receiving a message from the charging device that can be used to determine the vehicle's charging method. [Means for solving the problem]

[0008] The vehicle relating to the first aspect of this disclosure is configured to be externally charged by DC power supplied from a charging device via a charging cable. The vehicle includes an energy storage device that is charged with DC power from the charging device as charging power, a voltage sensor that detects the charging voltage of the charging power, a switching device configured to switch between charging methods with different charging voltages, and a control device that determines the charging method. The control device acquires the insulation diagnostic voltage applied by the charging device from the voltage sensor and determines the charging method based on the insulation diagnostic voltage.

[0009] The charging system relating to the second aspect of this disclosure comprises a charging device and a vehicle configured to be externally charged by DC power supplied from the charging device via a charging cable. The vehicle includes a power storage device that is charged with DC power from the charging device as charging power, a voltage sensor that detects the charging voltage of the charging power, a switching device configured to switch between charging methods with different charging voltages, and a control device that determines the charging method. When the vehicle and the charging device are connected via a charging cable, the charging device performs an insulation diagnosis of the charging device and, after the insulation diagnosis is performed, transmits a message to the control device indicating the maximum output voltage of the charging device. The control device obtains the insulation diagnosis voltage applied by the charging device from the voltage sensor during the insulation diagnosis and determines the charging method based on the insulation diagnosis voltage.

[0010] A vehicle charging method relating to the third aspect of this disclosure externally charges the vehicle using DC power supplied from a charging device via a charging cable as the charging power. The vehicle is configured to be switchable between charging methods with different charging voltages. The charging method includes the steps of: when the vehicle and the charging device are connected via a charging cable, the charging device performing an insulation diagnosis of the charging device; in the step of performing the insulation diagnosis, the vehicle acquiring the insulation diagnosis voltage applied by the charging device using a voltage sensor; the vehicle determining a charging method based on the insulation diagnosis voltage; and, after the step of determining the charging method, the charging device transmitting a message to the vehicle indicating the maximum output voltage of the charging device.

[0011] In the above configuration and method, the vehicle (control device) obtains the isolation diagnostic voltage applied by the charging device from a voltage sensor and determines the charging method based on the isolation diagnostic voltage. Therefore, the vehicle can determine its own charging method prior to receiving the message from the charging device. [Effects of the Invention]

[0012] According to this disclosure, a vehicle can determine its charging method prior to receiving a message from the charging device that can be used to determine the vehicle's charging method. [Brief explanation of the drawing]

[0013] [Figure 1] It is a schematic diagram showing the overall configuration of the charging system according to this embodiment. [Figure 2] It is a circuit block diagram showing in detail an example of the configuration of the charging system. [Figure 3] It is a circuit block diagram showing in detail an example of the configuration of the switching device and the battery pack. [Figure 4] It is a diagram for explaining the control of the switching device for realizing the high voltage method. [Figure 5] It is a diagram for explaining the control of the switching device for realizing the ultra-high voltage method. [Figure 6] It is a sequence diagram showing an example of the communication sequence of external charging. [Figure 7] It is a flowchart showing an example of the processing procedure for determining the charging method in this embodiment. [Figure 8] It is a conceptual diagram for explaining the insulation diagnosis in this embodiment. [Figure 9] It is a diagram for explaining the setting method of the maximum allowable voltage in the comparative example. [Figure 10] It is a diagram for explaining the setting method of the maximum allowable voltage in this modification example.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[0015] [Embodiment] <Overall Configuration of Charging System> FIG. 1 is a schematic diagram showing the overall configuration of the charging system according to the present embodiment. The charging system 100 includes a vehicle 1, a charging device 2, and a charging cable 3. In FIG. 1, a situation is shown where the vehicle 1 and the charging device 2 are connected via a vehicle plug 31 and a vehicle socket 11, and external charging is being performed from the charging device 2 to the vehicle 1.

[0016] The vehicle 1 is, for example, a battery electric vehicle (BEV). However, the vehicle 1 may be, for example, a plug-in hybrid electric vehicle (PHEV) as long as it is configured to be capable of external charging.

[0017] The charging device 2 is, for example, a DC (Direct Current) charging device that supplies DC power. The charging device 2 may be a rapid charging device 2B (see FIG. 4) provided at a public charging stand (also called a charging station), or may be an ultra-rapid charging device 2A (see FIG. 5).

[0018] FIG. 2 is a circuit block diagram showing an example of the configuration of the charging system 100 in detail. The charging device 2 converts the supplied power (AC power) from the system power source 900 (typically a commercial power source) into the charging power (DC power) of the vehicle 1, and supplies the DC power to the vehicle 1. The charging device 2 includes a contactor K0, a power conversion device 21, a current sensor 22, a fuse F, a bleeder circuit 23, an insulation monitoring device (IMD) 24, an electromagnetic contactor circuit 25, a voltage sensor 26, an auxiliary power source 27, an electromagnetic contactor circuit 28, a resistor R1, and a charging device controller 29.

[0019] The contactor K0 is electrically connected between the system power source 900 and the power conversion device 21. The contactor K0 switches between supplying and interrupting the AC power from the system power source 900 according to the control by the charging device controller 29.

[0020] The power converter 21 converts AC power from the grid power supply 900 into DC power for charging the battery pack 15 (described later) mounted on the vehicle 1. The power converter 21 includes, for example, an AC / DC converter 211, a transformer 212, a DC / DC converter 213, and a diode 214. The power converter 21 outputs the DC power to the DC+ and DC- power lines.

[0021] The current sensor 22 is electrically connected, for example, to the DC+ power supply line. The current sensor 22 detects the current flowing through the DC+ power supply line and outputs the detection result to the charging device controller 29. The fuse F is electrically connected, for example, to the DC+ power supply line. The bleeder circuit 23 is electrically connected between the DC+ and DC- power supply lines. The bleeder circuit 23 discharges a capacitor (not shown) provided on the output side of the power converter 21.

[0022] The insulation monitoring device 24 is electrically connected between the DC+ and DC- power lines. The insulation monitoring device 24 performs an insulation diagnosis of the charging device 2. More specifically, the insulation monitoring device 24 applies an insulation diagnosis voltage Vdiag (details described later) between the DC+ and DC- power lines and measures the insulation resistance under those conditions.

[0023] The electromagnetic contactor circuit 25 includes a contactor K1 connected to the DC+ power supply line and a contactor K2 connected to the DC- power supply line. The electromagnetic contactor circuit 25 switches between supplying and disconnecting DC power from the power converter 21 according to the control of the charging device controller 29.

[0024] The voltage sensor 26 is electrically connected between the DC+ and DC- power lines. The voltage sensor 26 detects the voltage between the DC+ and DC- power lines and outputs the detection result to the charging device controller 29.

[0025] The auxiliary power supply 27 supplies a low voltage to the vehicle controller 16 (described later) of the vehicle 1 via conductors A+ and A- to enable communication between the charging device controller 29 and the vehicle controller 16 of the vehicle 1.

[0026] The electromagnetic contactor circuit 28 includes a contactor K3 connected to conductor A+ and a contactor K4 connected to conductor A-. The electromagnetic contactor circuit 25 switches between supplying and disconnecting a low voltage from the auxiliary power supply 27 according to the control of the charging device controller 29.

[0027] Resistor R1 is connected between circuit CC1 from the charging device controller 29 and the pull-up voltage U1.

[0028] The charging device controller 29 includes a processor, memory, and input / output interfaces (none of which are shown). The processor controls the power supply operation from the charging device 2 to the vehicle 1 based on the current detected by the current sensor 22, the voltage detected by the voltage sensor 26, communication with the vehicle 1, and maps and programs stored in the memory.

[0029] The vehicle plug 31 includes a resistor R2, a resistor R3, and a switch S. Resistor R2 and switch S are connected in series between circuit CC1 and the ground wire GND. Resistor R3 is connected between circuit CC2 from the vehicle controller 16 and the ground wire GND.

[0030] Vehicle 1 includes a vehicle socket 11, an electromagnetic contactor circuit 12, a voltage sensor 13, a switching device 14, a battery pack 15, a resistor R5, and a vehicle controller 16.

[0031] The vehicle socket 11 is configured to allow insertion of the vehicle plug 31 of the charging cable 3 with mechanical connection such as mating. The vehicle socket 11 includes a resistor R4. The resistor R4 is connected between the circuit CC1 and the ground wire GND.

[0032] The electromagnetic contactor circuit 12 includes a contactor K5 connected to the DC+ power supply line and a contactor K6 connected to the DC- power supply line. The electromagnetic contactor circuit 12 switches between receiving and interrupting the charging power supplied via the vehicle socket 11 according to the control of the vehicle controller 16.

[0033] Voltage sensor 13 is electrically connected between the DC+ and DC- power lines. Voltage sensor 26 detects the charging voltage between the DC+ and DC- power lines and outputs the detection result to the vehicle controller 16. Voltage sensor 13 corresponds to the "voltage sensor" in this disclosure.

[0034] The switching device 14 is electrically connected between the electromagnetic contactor circuit 12 and the battery pack 15. The switching device 14 is configured to switch between charging methods with different charging voltages. The configuration of the switching device 14 is explained in Figures 3 to 5.

[0035] The battery pack 15 is electrically connected to the switching device 14. The battery pack 15 is a battery pack containing multiple battery modules. Each battery module contains multiple cells. Each cell is a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride battery. Each cell may also be a solid-state battery. The configuration of the battery pack 15 is explained in Figure 3. The battery pack 15 corresponds to the "energy storage device" in this disclosure. The "energy storage device" may be a capacitor such as an electric double-layer capacitor.

[0036] Resistor R5 is connected between circuit CC2 and pull-up voltage U2.

[0037] The vehicle controller 16 is an in-vehicle ECU (Electronic Control Unit) and includes a processor 161, a memory 162, and an input / output interface (not shown). The processor 161 includes processing circuitry such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit). The memory 162 includes volatile storage devices such as DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory), and non-volatile storage devices such as an HDD (Hard Disk Drive), SSD (Solid State Drive), and flash memory. The memory 162 stores a system program including an OS (Operating System) and a program for controlling the charging operation of the vehicle 1. The processor 161 performs various processes by reading the system program and other programs, loading them into the memory 162, and executing them. The vehicle controller 16 corresponds to the "control device" in this disclosure.

[0038] Although only one processor is shown in Figure 1, Vehicle 1 may contain multiple processors. In this specification, "processor" is not limited to a processor in the narrow sense that executes processing using a stored-program method, but may also include hardwired circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field-Programmable Gate Arrays). Therefore, the term "processor" can also be interpreted as a circuit or processing circuitry whose processing is predefined by computer-readable code and / or hardwired circuits.

[0039] <Switching charging methods> Figure 3 is a circuit block diagram showing in detail an example of the configuration of the switching device 14 and the battery pack 15. The switching device 14 includes, for example, five contactors 41-45 and two current sensors 46, 47. The battery pack 15 includes, for example, two battery modules 51, 52. Battery modules 51 and 52 are modules having the same voltage level (typically modules containing the same number of cells of the same type). The fully charged voltage of each battery module 51, 52 is, for example, 400V.

[0040] Contactor 41 is electrically connected between the vehicle socket 11 and node N1 on the DC+ power supply line. Contactor 42 is electrically connected between the vehicle socket 11 and node N2 on the DC- power supply line. Contactor 43 is electrically connected between node N1 and the positive terminal of battery module 52. Contactor 44 is electrically connected between node N2 and the negative terminal of battery module 51. Contactor 45 is electrically connected between the negative terminal of battery module 51 and the positive terminal of battery module 52. Each contactor 41 to 45 is closed (on) / opened (off) according to the control of the vehicle controller 16.

[0041] Current sensor 46 is electrically connected between node N1 and the positive terminal of battery module 51. Current sensor 47 is electrically connected between node N2 and the negative terminal of battery module 52.

[0042] The switching device 14 and the battery pack 15 are configured to allow switching between a high-voltage system and an ultra-high-voltage system. The charging voltage for the ultra-high-voltage system is higher than the charging voltage for the high-voltage system.

[0043] Figure 4 is a diagram illustrating the control of the switching device 14 for realizing the high-voltage method. When the rapid charger 2B is connected to the vehicle plug 31, the vehicle controller 16 closes contactors 41-44 and opens contactor 45. This connects battery module 51 and battery module 52 in parallel. This realizes a state of the battery pack 15 suitable for high-voltage charging.

[0044] Figure 5 is a diagram illustrating the control of the switching device 14 for realizing the ultra-high voltage method. When the ultra-fast charger 2A is connected to the vehicle plug 31, the vehicle controller 16 closes contactors 41, 42, and 45, and opens contactors 43 and 44. As a result, battery module 51 and battery module 52 are connected in series. This realizes a state for the battery pack 15 that is suitable for charging using the ultra-high voltage method.

[0045] The ultra-high voltage method corresponds to the "first method" as described in this disclosure. The high voltage method corresponds to the "second method" as described in this disclosure. For the sake of clarity, here we have described an example in which the charging voltage of the "first method" is twice that of the "second method," and in order to accommodate this, the connection between battery module 51 and battery module 52 is switched between series and parallel connections. However, the charging voltages of the "first method" and the "second method" are not limited to these. For example, when there are more battery modules (three or more), the connection relationships between the battery modules are switched in a more complex manner to accommodate the voltage relationship (voltage difference or voltage ratio) between the "first method" and the "second method."

[0046] <Communication Sequence> Figure 6 is a sequence diagram showing an example of a communication sequence in external charging. In the diagram, the processes performed by the charging device 2 (charging device controller 29) are shown on the left, and the processes performed by the vehicle 1 (vehicle controller 16) are shown on the right. This communication sequence is initiated when the vehicle 1 and the charging device 2 are mechanically connected by the charging cable 3, and a low voltage is supplied to enable communication between the vehicle 1 and the charging device 2. Each process (indicated by P) is classified into a handshake phase, a placement phase, a charging phase, or a termination phase.

[0047] Figure 6 illustrates an example assuming a specific charging standard (specifically GB / T18487.1). For details on each message, refer to GB / T27930, for example. However, those skilled in the art can apply the following explanation by analogy to various charging standards.

[0048] Referring to Figures 2 and 6, when the vehicle plug 31 of the charging cable 3 is connected to the vehicle socket 11 and the switch S is turned on, the voltage of circuit CC1 in the charging device 2 becomes the pull-up voltage U1 (e.g., 4V) (P1), and the voltage of circuit CC2 in the vehicle 1 becomes the pull-up voltage U2 (e.g., 6V) (P2). When the charging device controller 29 detects that the potential of circuit CC1 has become the pull-up voltage U1, it locks an electronic lock (not shown) provided at the connection between the vehicle plug 31 and the vehicle socket 11 (P3). Next, the charging device controller 29 closes the contactors K3 and K4 of the electromagnetic contactor circuit 28 (P4).

[0049] ≪Handshake Phase≫ During the handshake phase, a communication link is established between vehicle 1 (vehicle controller 16) and charging device 2 (charging device controller 29). Specifically, the charging device controller 29 sends a message CHM to the vehicle controller 16 to confirm the handshake between vehicle 1 and charging device 2 (P5).

[0050] When the voltage of circuit CC2 in vehicle 1 becomes the pull-up voltage U2 and the vehicle controller 16 receives the message CHM from the charging device controller 29, the vehicle controller 16 sends the message BHM to the charging device controller 29 to confirm the handshake (P6). The message BHM may include the maximum allowable voltage Vmax, which will be described later.

[0051] When the vehicle controller 16 receives the message BHM, the charging device controller 29 performs an insulation diagnosis of the charging device 2 using the insulation monitoring device 24 (P7). If the insulation state of the charging device 2 is normal, the charging device controller 29 turns on the bleeder circuit 23 to discharge the voltage accumulated in the power converter 21 as a result of the insulation diagnosis (P8).

[0052] When the discharge by the bleeder circuit 23 is complete, the charging device controller 29 sends message CRM to the vehicle controller 16 (P9). Message CRM is an identification message sent from the charging device controller 29 to the vehicle controller 16 to confirm that the communication link between the charging device 2 and the vehicle 1 is correct. is a predetermined parameter included in message CRM, indicating that the charging device controller 29 has not yet been able to identify the vehicle 1.

[0053] When the vehicle controller 16 receives message CRM from the charging device controller 29, it sends message BRM to the charging device controller 29 (P10). Message BRM contains identification information for vehicle 1. Message BRM includes information such as the version number of the communication protocol installed in vehicle 1, the type of battery pack 15, the rated capacity, and the rated voltage.

[0054] Upon receiving message BRM from vehicle controller 16, charging device controller 29 sends message CRM� to vehicle controller 16 (P11). � is a parameter included in message CRM, indicating that charging device controller 29 has identified vehicle 1. This completes the handshake between vehicle 1 and charging device 2, and processing proceeds to the deployment stage.

[0055] ≪Placement Stage≫ During the deployment phase, charging conditions are determined, and the success or failure of the charging preparation is confirmed. Specifically, when the vehicle controller 16 receives message CRM� from the charging device controller 29, it sends message BCP to the charging device controller 29 (P12). Message BCP is a message concerning the charging parameters (charging conditions) of the battery pack 15. Message BCP includes information such as the maximum allowable total charging voltage, maximum allowable charging current, full charge capacity (nominal total energy), maximum allowable total charging voltage, maximum allowable temperature, current SOC (State Of Charge) (charge state), and current total voltage of the battery pack 15.

[0056] Hereafter, the maximum allowable total charging voltage will be referred to as "maximum allowable voltage Vmax". The maximum allowable voltage Vmax is the voltage when the charging method is switched by the switching device 13 to the method with the highest charging voltage (in this example, the ultra-high voltage method) and the battery pack 15 is fully charged; in short, it is the highest voltage that the battery pack 15 can achieve. The maximum allowable voltage Vmax is a fixed value predetermined according to the specifications of the battery pack 15 (full charge voltage of each cell, number of cells connected in series, etc.).

[0057] Upon receiving message BCP from vehicle controller 16, charging device controller 29 transmits message CTS to vehicle controller 16 (P13). Message CTS is time information to be synchronized between vehicle 1 and charging device 2. Furthermore, charging device controller 29 transmits message CML to vehicle controller 16 (P14). Message CML contains information regarding the maximum output capacity of charging device 2. Message CML includes, for example, information such as the maximum output voltage, minimum output voltage, maximum output current, and minimum output current of charging device 2.

[0058] When the vehicle controller 16 receives message CML from the charging device controller 29, it sends message BRO to the vehicle controller 16 (P15). Message BRO is a message indicating whether or not charging preparation is complete in vehicle 1. is a predetermined parameter included in message BRO, which indicates that charging preparation is not yet complete in vehicle 1.

[0059] When the vehicle controller 16 transmits message BRO to the charging device controller 29, it closes contactors K5 and K6 of the electromagnetic contactor circuit 12 (P16). Furthermore, the vehicle controller 16 performs an insulation diagnosis of vehicle 1 using an insulation monitoring meter (not shown in Figure 2) installed in vehicle 1 (P17). If the insulation state of vehicle 1 is normal, the vehicle controller 16 transmits message BRO to the charging device controller 29 (P18). � is a parameter of message BRO and indicates that charging preparation is complete in vehicle 1.

[0060] When the charging device controller 29 receives message BRO� from the vehicle controller 16, it closes contactors K1 and K2 of the electromagnetic contactor circuit 25 (P19). Furthermore, the charging device controller 29 transmits message CRO� to the vehicle controller 16 (P20). Message CRO indicates whether or not the charging device 2 is ready to charge. � is a predetermined parameter included in message CRO, indicating that the charging device 2 is ready to charge. This enables power supply from the charging device 2 and charging of the vehicle 1, and the process moves to the charging stage.

[0061] ≪Charging Stage≫ During the charging phase, the power converter 21 in the charging device 2 is driven to supply power to the vehicle 1, and the battery pack 15 in the vehicle 1 is charged. Specifically, the vehicle controller 16 transmits messages BCS and BCL to the charging device controller 29 (P21, P22). Message BCS includes, for example, information regarding the charging voltage, charging current, and SOC of the battery pack 15, as well as an estimated remaining charging time. Message BCL includes, for example, information regarding the requested voltage and current from the vehicle 1 to the charging device 2, as well as the charging mode (constant voltage charging mode or constant current charging mode).

[0062] The charging device controller 29 adjusts the charging current by appropriately controlling the power converter 21 (P23). The charging device controller 29 also transmits message CCS to the vehicle controller 16 (S24). Message CCS is a message for notifying the start (continuation) of charging and includes, for example, information regarding the output voltage and output current of the charging device 2.

[0063] While the battery pack 15 is charging, the vehicle controller 16 sends messages BSM, BMV, BML, and BSP to the charging device controller 29 (P25~P28). Message BSM is a message indicating the State of Charge (SOC) of the battery pack 15. Message BMV is a message indicating the voltage of the battery pack 15. Message BML is a message indicating the temperature of the battery pack 15. Message BSP is a preliminary message to notify the charging device controller 29 of the status of the battery pack 15.

[0064] The charging device controller 29 then determines whether the conditions for stopping power supply have been met, and if it is determined that the conditions have been met, it stops supplying power from the charging device 2 to the vehicle 1 (P29). Meanwhile, the vehicle controller 16 determines whether the conditions for stopping charging have been met, and if it is determined that the conditions have been met, it stops charging the vehicle 1 (P30). At this time, the vehicle controller 16 sends a message BST to the charging device controller 29 indicating that the vehicle 1 has stopped charging (P31). Message BST may include information regarding the cause of the vehicle 1 stopping charging. The charging device controller 29 also sends a message CST to the vehicle controller 16 indicating that the charging device 2 has stopped supplying power. Message CST may include information regarding the cause of the charging device 2 stopping power supply.

[0065] Subsequently, the charging device controller 29 opens contactors K1 and K2 of the electromagnetic contactor circuit 25 (P32). The vehicle controller 16 opens contactors K5 and K6 of the electromagnetic contactor circuit 12 (P33). Furthermore, the charging device controller 29 closes the bleeder circuit 23 to discharge the voltage stored in the power converter 21 (P34). This completes the charging stage, and the process proceeds to the final stage.

[0066] <<Final Stage>> At the end of the process, statistical data regarding the charging is exchanged between vehicle 1 and charging device 2. Specifically, vehicle controller 16 sends message BSD to charging device controller 29, which shows the statistical data for vehicle 1 during the charging process (P35). On the other hand, charging device controller 29 sends message CSD to vehicle controller 16, which shows the statistical data for charging device 2 during the charging process (P36).

[0067] Next, the charging device controller 29 opens contactors K3 and K4 of the electromagnetic contactor circuit 28 (P37). Finally, the charging device controller 29 releases the electronic lock at the connection between the vehicle plug 31 and the vehicle socket 11 (P38). This completes the external charging as defined in the communication protocol.

[0068] <Maximum output capacity of the charging device> In the communication protocol illustrated in Figure 6, the maximum output capacity (especially the maximum output voltage) of the charging device 2 is transmitted from the charging device 2 to the vehicle 1 via the CML message during the deployment phase (see P14). It is also conceivable that the vehicle 1 would determine its charging method based on the maximum output voltage of the charging device 2. However, in some cases, it is preferable for the vehicle 1 to determine the charging method before receiving the CML message from the charging device 2. Depending on the charging device 2, if the vehicle 1 changes the charging method after the CML message has been sent, the communication sequence shown in Figure 6 may be terminated as the vehicle 1 has performed an abnormal operation, and power may not be supplied from the charging device 2 to the vehicle 1.

[0069] Therefore, in this embodiment, the vehicle controller 16 determines the charging method of vehicle 1 by utilizing the opportunity of the insulation diagnosis (see P7) performed by the charging device controller 29 during the handshake phase prior to the deployment phase. This prevents the charging method of vehicle 1 from being changed after the transmission of the message CML from the charging device 2 to vehicle 1. Thus, even if the charging device 2 is a device that does not support changes in the charging method after the transmission of the message CML, external charging of vehicle 1 can be performed more reliably.

[0070] <Processing Flow> Figure 7 is a flowchart illustrating an example of a processing procedure for determining the charging method in this embodiment. The processing shown in this flowchart is executed when predetermined conditions are met (for example, when it is detected that the vehicle 1 and the charging device 2 are connected by the charging cable 3). In the figure, the processing by the charging device 2 (charging device controller 29) is shown on the left, and the processing by the vehicle 1 (vehicle controller 16) is shown on the right. Each step is typically implemented by software processing, but may also be implemented by hardware processing. Hereinafter, each step will be abbreviated as S.

[0071] Referring to Figures 2 and 7, in S11, vehicle 1 transmits a predetermined maximum allowable voltage Vmax to the charging device 2 during the handshake phase. As mentioned above, the maximum allowable voltage Vmax is the highest voltage that the battery pack 15 can take. In the examples of Figures 3 to 5, the maximum allowable voltage Vmax is defined as the voltage when battery module 51 and battery module 52 are connected in series and both battery modules 51 and 52 are fully charged. If the fully charged voltage of each battery module 51 and 52 is 400V, the maximum allowable voltage Vmax is approximately 800V. In the communication sequence described in Figure 6, vehicle 1 may also transmit the maximum allowable voltage Vmax in the message BHM for confirming the handshake (see P6 in Figure 6). This message corresponds to the "maximum allowable voltage message" in this disclosure.

[0072] In steps S21 to S24, the charging device 2 performs an insulation diagnosis of the charging device 2 using the insulation monitoring device 24 (see P7 in Figure 6). In the insulation diagnosis, the charging device 2 sets the insulation diagnosis voltage Vdiag according to the maximum allowable voltage Vmax received from the vehicle 1.

[0073] FIG. 8 is a conceptual diagram for explaining the insulation diagnosis in the present embodiment. Referring to FIGS. 7 and 8, when the charging device 2 is the ultra-rapid charging device 2A, the rated voltage (the maximum voltage that the charging device 2 can supply) Vrated of the charging device 2 is higher than the rated voltage of the charging device 2 when the charging device 2 is the rapid charging device 2B. For the vehicle 1, at the stage of insulation diagnosis of the charging device 2, the rated voltage of the charging device 2 is unknown, whereas for the charging device 2, its own rated voltage Vrated is known.

[0074] In S21, when the charging device 2 receives the maximum allowable voltage Vmax from the vehicle 1 in S11, the charging device 2 compares the maximum allowable voltage Vmax with the rated voltage Vrated and determines which voltage is lower (S21). This is because the insulation diagnosis voltage Vdiag is set to the lower of the rated voltage Vrated and the maximum allowable voltage Vmax.

[0075] Specifically, when the charging device 2 is the ultra-rapid charging device 2A, the maximum allowable voltage Vmax is lower than the rated voltage Vrated (Vmax < Vrated in S21). Therefore, the charging device 2 sets the insulation diagnosis voltage Vdiag to the maximum allowable voltage Vmax (S22). On the other hand, when the charging device 2 is the rapid charging device 2B, the rated voltage Vrated is less than or equal to the maximum allowable voltage Vmax (Vrated ≦ Vmax in S21). Therefore, the charging device 2 sets the insulation diagnosis voltage Vdiag to the rated voltage Vrated (S23).

[0076] In S24, the charging device 2 applies the insulation diagnosis voltage Vdiag set in S22 or S23 between the power supply line DC+ and the power supply line DC-. Then, the charging device 2 measures the insulation resistance between the power supply line DC+ and the power supply line DC- when the insulation diagnosis voltage Vdiag is applied.

[0077] During the insulation diagnosis performed by the charging device 2, in S12, the vehicle 1 obtains the insulation diagnosis voltage Vdiag applied by the charging device 2 from the voltage sensor 13. Then, the vehicle 1 compares the insulation diagnosis voltage Vdiag with a predetermined reference voltage Vref and determines which voltage is higher (S13). The reference voltage Vref is a positive fixed voltage excluding 0V. The reference voltage Vref is set to be higher than the allowable voltage when the battery pack 15 (at least one of the battery modules 51 and 52 connected in parallel) is fully charged in the high-voltage system, and lower than the allowable voltage (i.e., the maximum allowable voltage Vmax) when the battery pack 15 (battery modules 51 and 52 connected in series) is fully charged in the ultra-high-voltage system.

[0078] If the insulation diagnostic voltage Vdiag is higher than the reference voltage Vref (Vdiag > Vref in S13), it can be estimated that the charging device 2 is likely to be the ultra-fast charging device 2A, and therefore, vehicle 1 decides to set its charging method to the ultra-high voltage method (see Figure 5) (S14). On the other hand, if the insulation diagnostic voltage Vdiag is less than or equal to the reference voltage Vref (Vdiag ≤ Vref in S13), it can be estimated that the charging device 2 is likely to be the fast charging device 2B, and therefore, vehicle 1 decides to set its charging method to the high voltage method (see Figure 4) (S15).

[0079] Although not shown, vehicle 1 may further control the switching device 14 to conform to the determined charging method (see Figures 4 and 5). However, the timing of controlling the switching device 14 is not limited to this. The switching device 14 is controlled at an appropriate timing after processing S14 or S15 and before the charging stage S17, described later, begins.

[0080] In S16, vehicle 1 transmits the charging method determined in S14 or S15 to the charging device 2. In the communication protocol described in Figure 6, vehicle 1 may include the charging method of vehicle 1 in message BRM, which contains the identification information of vehicle 1 (see P10 in Figure 6). Alternatively, vehicle 1 may include the charging method of vehicle 1 in message BCP, which notifies the charging device 2 of the charging parameters of the battery pack 15 (see P12 in Figure 6). These messages correspond to the "charging method messages" as described herein.

[0081] In S25, the charging device 2 transmits its maximum output voltage to the vehicle 1. In the communication sequence described in Figure 6, the maximum output voltage is transmitted as part of a message CML that includes information about the maximum output capability of the charging device 2 (see P14).

[0082] In addition, other processes during the handshake and placement phases, which are explained in detail in Figure 6, will also be performed. These processes have already been explained in detail in Figure 6, and to avoid complexity, they will not be explained again here.

[0083] Subsequently, vehicle 1 and charging device 2 perform the processes of the charging stage (S17, S26). Finally, vehicle 1 and charging device 2 perform the processes of the termination stage (S18, S27).

[0084] As described above, in this embodiment, prior to receiving the message CML indicating the maximum output voltage of the charging device 2 from the charging device controller 29, the vehicle controller 16 takes advantage of the opportunity to perform an insulation diagnosis on the charging device 2 to acquire the insulation diagnostic voltage Vdiag of the charging device 2 using the voltage sensor 13. The vehicle controller 16 then compares the insulation diagnostic voltage Vdiag with a reference voltage Vref that is lower than the insulation diagnostic voltage Vdiag. If the insulation diagnostic voltage Vdiag is higher than the reference voltage Vref, it can be estimated that the rated voltage Vrated of the charging device 2 is higher than the maximum allowable voltage Vmax (it is an ultra-high voltage). Conversely, if the insulation diagnostic voltage Vdiag is higher than or equal to the reference voltage Vref, it can be estimated that the rated voltage Vrated of the charging device 2 is lower than or equal to the maximum allowable voltage Vmax (it is a high voltage). Since the rated voltage Vrated and the maximum output voltage are strongly correlated, if the rated voltage Vrated is an ultra-high voltage, the maximum output voltage is also an ultra-high voltage, and if the rated voltage Vrated is a high voltage, the maximum output voltage is also a high voltage. Therefore, the vehicle controller 16 can determine the charging method for vehicle 1 based on the rated voltage Vrated of the charging device 2, even if it has not obtained the maximum output voltage of the charging device 2. Thus, according to this embodiment, the charging method for vehicle 1 can be determined prior to the maximum output voltage of the charging device 2 being transmitted from the charging device 2 to vehicle 1.

[0085] [Differentiation] Figure 7 illustrates how the vehicle controller 16 sends a message to the charging device controller 29 indicating the maximum allowable voltage Vmax of vehicle 1. In this modified example, the method of setting the maximum allowable voltage Vmax improves the accuracy of determining the charging method for vehicle 1. To facilitate understanding, a comparative example will be used as an example first.

[0086] <Setting the maximum allowable voltage> Figure 9 is a diagram illustrating the method for setting the maximum allowable voltage Vmax in a comparative example. As mentioned above, when the maximum allowable voltage Vmax is lower than the rated voltage Vrated of the charging device 2 (in the case of an ultra-fast charging device), the insulation diagnostic voltage Vdiag is set to the maximum allowable voltage Vmax, but output errors of the charging device 2 may occur in the insulation diagnostic voltage Vdiag. In addition, detection errors may occur in the voltage sensor 13 that detects the insulation diagnostic voltage Vdiag. Therefore, when the maximum allowable voltage Vmax is lower than the rated voltage Vrated, an error range ER1, shown by the shaded area in the figure, may exist in the insulation diagnostic voltage Vdiag. The error range ER1 may also be called the error range of the allowable voltage in ultra-fast charging (first method).

[0087] On the other hand, if the rated voltage Vrated is lower than the maximum allowable voltage Vmax (in the case of a rapid charger), the insulation diagnostic voltage Vdiag is set to the rated voltage Vrated. Similarly, in this case as well, the insulation diagnostic voltage Vdiag may be subject to output errors from the charging device 2 and detection errors from the voltage sensor 13. Therefore, even when the rated voltage Vrated is lower than the maximum allowable voltage Vmax, the insulation diagnostic voltage Vdiag may also have an error range ER2, indicated by the diagonal lines. The error range ER2 may also be called the error range of the allowable voltage in rapid charging (second method).

[0088] Assuming that the voltage difference between the maximum allowable voltage Vmax and the rated voltage Vrated of the rapid charger is relatively small, there is a possibility that a portion of the error range ER1 and a portion of the error range ER2 may overlap. If a reference voltage Vref is set in this overlapping portion, the vehicle controller 16 may incorrectly determine the relative magnitudes of the insulation diagnostic voltage Vdiag and the reference voltage Vref in the process of S13 in Figure 7. In that case, the vehicle controller 16 may not be able to correctly determine the charging method for vehicle 1.

[0089] Figure 10 is a diagram illustrating the method for setting the maximum allowable voltage in this modified example. In this embodiment, the vehicle controller 16 raises the maximum allowable voltage by a predetermined voltage Vα compared to Vmax in the comparative example. In other words, the vehicle controller 16 sets the maximum allowable voltage Vmax' in this modified example to Vmax' = Vmax + Vα (Vα > 0). Vα is determined so that the error ranges ER1 and ER2 do not overlap at all, taking into account the output error of the charging device 2 and the detection error of the voltage sensor 13. In other words, the maximum allowable voltage Vmax is determined such that the lower limit voltage of the error range ER1 of the maximum allowable voltage is higher than the upper limit voltage of the error range ER2 of the rated voltage Vrated of the rapid charger. As a result, the reference voltage Vref is not included in both the error range ER1 and the error range ER2, so the vehicle controller 16 can accurately determine the magnitude relationship between the insulation diagnostic voltage Vdiag and the reference voltage Vref. Therefore, the accuracy of the vehicle controller 16's determination of the charging method of vehicle 1 can be improved.

[0090] Let's explain with a specific example. Assume that the rated voltage Vrated of the rapid charging equipment is 400V (with a lower limit voltage of error range ER2 = 300V and an upper limit voltage = 500V), and the rated voltage Vrated of the ultra-rapid charging equipment is 800V (with a lower limit voltage of error range ER1 = 700V and an upper limit voltage = 900V). In this case, the maximum allowable voltage Vmax is set within the range of 500V to 700V, preferably within the range of 610V to 650V. The reference voltage Vref can be set to 600V.

[0091] In the embodiments and modifications described above, the charging method was explained as being determined to be one of two methods (high-voltage method and high-voltage method). However, for example, there may be three charging methods (three types of charging devices 2), and the vehicle 1 may support these three charging methods. In that case, by setting two reference voltages, one of the three charging methods can be determined. Thus, according to this embodiment, even if the vehicle 1 supports N methods (where N is any natural number greater than or equal to 3), an appropriate charging method can be determined for the charging device 2 by setting (N-1) reference voltages.

[0092] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0093] 1 Vehicle, 11 Vehicle socket, 12 Electromagnetic contactor circuit, 13 Voltage sensor, 14 Switching device, 15 Battery pack, 16 Vehicle controller, 161 Processor, 162 Memory, 21 Power converter, 2 Charging device, 2A Super-fast charger, 2B Fast charger, 3 Charging cable, 211 AC / DC converter, 212 Transformer, 213 DC / DC converter, 214 Diode, 22 Current sensor, 23 Bleeder circuit, 24 Insulation monitoring device, 25 Electromagnetic contactor circuit, 26 Voltage sensor, 27 Auxiliary power supply, 28 Electromagnetic contactor circuit, 29 Charging device controller, 31 Vehicle plug, 41-45 Contactor, 46,47 Current sensor, 51,52 Battery module, 100 Charging system, 900 System power supply, A+ conductor, A- conductor, DC+ Power supply line, DC- power supply line, F fuse, GND ground wire, K0-K6 contactors, R1-R5 resistors, S switch.

Claims

1. A vehicle configured to allow external charging using DC power supplied from a charging device via a charging cable, A power storage device that is charged using the DC power from the charging device as its charging power, A voltage sensor for detecting the charging voltage of the aforementioned charging power, A switching device configured to enable switching between charging methods with different charging voltages, The system includes a control device for determining the charging method, The control device acquires an insulation diagnostic voltage applied by the charging device from the voltage sensor and determines the charging method based on the insulation diagnostic voltage, in a vehicle.

2. The control device transmits a maximum allowable voltage message indicating the maximum allowable voltage of the vehicle to the charging device. The vehicle according to claim 1, wherein the maximum allowable voltage is the voltage when the charging method is switched by the switching device to the method with the highest charging voltage and the energy storage device is fully charged.

3. The vehicle according to claim 2, wherein the control device transmits a charging method message to the charging device indicating the charging method determined based on the insulation diagnostic voltage.

4. The aforementioned vehicle complies with the charging standard GB / T18487. The aforementioned maximum allowable voltage message is message BHM, The vehicle according to claim 3, wherein the charging method message is message BRM or message BCP.

5. The charging method includes a first method and a second method having a lower charging voltage compared to the first method. The control device is If the insulation diagnostic voltage is higher than a predetermined reference voltage, the charging method is determined to be the first method, The vehicle according to any one of claims 2 to 4, wherein the charging method is determined to be the second method when the insulation diagnostic voltage is lower than the reference voltage.

6. The vehicle according to claim 5, wherein the reference voltage is a fixed voltage set lower than the maximum allowable voltage.

7. The lower limit voltage of the error range of the maximum allowable voltage is set to be higher than the upper limit voltage of the error range of the allowable voltage in the second method. The vehicle according to claim 6, wherein the reference voltage is determined between the lower limit voltage and the upper limit voltage.

8. Charging device and The vehicle comprises a vehicle configured to enable external charging using DC power supplied from the charging device via a charging cable, The aforementioned vehicle is A power storage device that is charged using the DC power from the charging device as its charging power, A voltage sensor for detecting the charging voltage of the aforementioned charging power, A switching device configured to enable switching between charging methods with different charging voltages, Includes a control device for determining the charging method, The charging device is When the vehicle and the charging device are connected via the charging cable, an insulation diagnosis of the charging device is performed, and after the insulation diagnosis is performed, a first message indicating the maximum output voltage of the charging device is transmitted to the control device. The control device acquires the insulation diagnostic voltage applied by the charging device during the insulation diagnostic from the voltage sensor, and determines the charging method based on the insulation diagnostic voltage, in a charging system.

9. Prior to the charging device performing the insulation diagnosis, the control device transmits a second message to the charging device indicating the maximum allowable voltage of the vehicle. The maximum allowable voltage is the voltage when the charging method is switched by the switching device to the method with the highest charging voltage and the energy storage device is fully charged. The charging system according to claim 8, wherein the charging device applies the lower of the maximum allowable voltage and the rated voltage of the charging device as the insulation diagnostic voltage.

10. The charging system according to claim 9, wherein the control device transmits a third message to the charging device indicating the charging method determined based on the isolation diagnostic voltage, prior to receiving the first message.

11. The aforementioned vehicle and charging device conform to the charging standard GB / T18487. The first message is a message CML, The second message is message BHM, The charging system according to claim 10, wherein the third message is message BRM or message BCP.

12. A method for charging a vehicle, wherein the vehicle is externally charged using DC power supplied from a charging device via a charging cable as the charging power, The vehicle is configured to allow switching between charging methods with different charging voltages for the charging power. The aforementioned charging method is When the vehicle and the charging device are connected via the charging cable, the charging device performs an insulation diagnosis of the charging device. In the step of performing the insulation diagnosis, the vehicle acquires the insulation diagnosis voltage applied by the charging device using a voltage sensor, The steps include: The vehicle determining the charging method based on the insulation diagnostic voltage; A method for charging a vehicle, comprising the step of determining the charging method, followed by the step of transmitting a message from the charging device to the vehicle indicating the maximum output voltage of the charging device.

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