Electric vehicle

Abstract

To suppress erroneous diagnosis of welding abnormality of a charging relay.SOLUTION: A first abnormality diagnosis for diagnosing a welding abnormality of a charging relay is performed in a state where an external power supply device is connected immediately after charging of a power storage device by power from the external power supply device is completed. When it is diagnosed that there is a possibility of the welding abnormality by the first abnormality diagnosis, the system is set to the sleep mode by the system end due to the end of the abnormality diagnosis, and when a predetermined condition thereafter is established, the second abnormality diagnosis for diagnosing the welding abnormality of the charging relay is performed in a state where the external power supply device is not connected.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electric vehicle, and more particularly to an electric vehicle equipped with a power storage device that can be charged with power from an external DC charging device. [Background technology]

[0002] Conventionally, for this type of electric vehicle, a device has been proposed that diagnoses whether the quick charging contactor is welded when charging of the onboard high-voltage battery from an external power source is completed (see, for example, Patent Document 1). In this electric vehicle, when the welding diagnosis means diagnoses that the quick charging contactor is welded, a notification is issued to prompt a retry of the welding diagnosis, and it is determined whether the quick charging connector is connected to the quick charging inlet. If it is determined that the quick charging connector is connected, the quick charging contactor welding diagnosis is retried. Such retries prevent erroneous diagnosis of a welding of the charging circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-033594 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described electric vehicle, since the rapid charge contactor welding diagnosis is retried when it is determined that the rapid charge connector is connected to the rapid charge inlet, if a false diagnosis of welding is made due to the rapid charge connector being connected to the rapid charge inlet, the false diagnosis cannot be avoided even if the diagnosis is retried. An electric vehicle disclosed herein has a primary object to suppress false diagnosis of welding abnormalities in the charging relay. [Means for solving the problem]

[0005] The electric vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object. The electric vehicle disclosed herein is an electric vehicle including: a drive device that outputs power for driving; a power storage device that supplies power to the drive device; a system main relay attached to a drive power line connecting the power storage device and the drive device; a vehicle-side connection part that connects to an external connection part from an external power supply device outside the vehicle; a charging relay attached to a charging power line that connects the drive power line and the vehicle-side connection part between the system main relay and the drive device; and a control device that controls charging of the power storage device with power from the external power supply device and performs a first abnormality diagnosis to diagnose a welding abnormality in the charging relay while the external power supply device is connected immediately after charging of the power storage device with power from the external power supply device is completed, wherein the control device, when it determines that there is a possibility of a welding abnormality based on the first abnormality diagnosis, enters a sleep mode by shutting down the system upon completion of the first abnormality diagnosis, and then starts up the system when a predetermined condition is met, and performs a second abnormality diagnosis to diagnose a welding abnormality in the charging relay while the external power supply device is connected.

[0006] In the electric vehicle disclosed herein, immediately after charging of the power storage device using power from the external power supply is completed, a first abnormality diagnosis is performed to diagnose whether the charging relay has a welding abnormality while the external power supply is connected. If the first abnormality diagnosis indicates a possibility of a welding abnormality, the system is shut down upon completion of the first abnormality diagnosis and placed into sleep mode. Thereafter, when a predetermined condition is met, the system is started up and a second abnormality diagnosis is performed to diagnose whether the charging relay has a welding abnormality while the external power supply is not connected. By performing this second abnormality diagnosis, it is possible to prevent an erroneous diagnosis of a welding abnormality in the charging relay due to the connection of the external power supply. Note that an erroneous diagnosis of a charging relay due to the connection of the external power supply may be caused by, for example, a relatively high voltage being applied to the vehicle side from the external power supply.

[0007] In the electric vehicle of the present disclosure, examples of the specified conditions include a condition in which the connection of the external connection part to the vehicle connection part is released, a condition in which a specified time has passed since this connection was released, a condition in which the lid covering the vehicle connection part is closed, or a condition in which a specified time has passed since this lid was closed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an outline of the configuration of an electric vehicle 20 according to an embodiment of the present disclosure. [Figure 2] 10 is a flowchart showing an example of processing after charging ends. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 according to one embodiment of the present disclosure. As shown in the figure, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a battery 36, a boost converter 40, a high-voltage power line 42, a low-voltage power line 44, a system main relay 38, a charging power line 50, a vehicle-side inlet 54, and an electronic control unit 70.

[0010] The motor 32 is configured as a synchronous generator motor and includes a rotor with an embedded permanent magnet and a stator around which a three-phase coil is wound. The rotor of the motor 32 is connected to a drive shaft 26 that is coupled to the drive wheels 22a, 22b via a differential gear 24. The inverter 34 is connected to the motor 32 and to a high-voltage power line 42. The inverter 34 is configured as a well-known inverter circuit including six transistors and six diodes. The battery 36 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to a low-voltage power line 44. The boost converter 40 is connected to the high-voltage power line 42 and the low-voltage power line 44 and is configured as a well-known buck-boost converter circuit including two transistors, two diodes, and a reactor.

[0011] A high-voltage-side capacitor 46 is connected to the positive and negative bus bars of the high-voltage-side power line 42. A low-voltage-side capacitor 48 is attached to the positive and negative bus bars of the low-voltage-side power line 44. A system main relay 38 is attached to the low-voltage-side power line 44. This system main relay 38 has a positive-side relay SMRB attached to the positive bus bar of the low-voltage-side power line 44, a negative-side relay SMRG attached to the negative bus bar of the low-voltage-side power line 44, and a pre-charge circuit in which a pre-charge resistor R and a pre-charge relay SMRP are connected in series to bypass the negative-side relay SMRG. A DC / DC converter 82 is connected to the low-voltage-side power line 44, and exchanges power with an auxiliary battery 86 and an auxiliary power line 84 to which an auxiliary device (not shown) is connected.

[0012] One end of the charging power line 50 is connected to the boost converter 40 side (motor 32 side) of the low-voltage power line 44 via the system main relay 38, and the other end is connected to a vehicle-side inlet 54. A charging relay 52 is attached to the charging power line 50. The charging relay 52 has a positive-side relay DCRB provided on the positive line of the charging power line 50 and a negative-side relay DCRG provided on the negative line of the charging power line 50. The charging power line 50 is connected to an external charging power line 150 extending from the external DC power supply 120 by connecting an external connector 154 of the external DC power supply 120 to the vehicle-side inlet 54. The external DC power supply 120 is connected to an external commercial power supply (not shown), and converts power from the commercial power supply into DC power and supplies it from the external charging power line 150.

[0013] When the external connector 154 is connected, the vehicle-side inlet 54 is connected to a connection line 58 which is connected to an external connection line 158 of the external DC power supply 120 via the external connector 154, and a communication line 60 which is connected to an external communication line 160 which is connected to the external DC power supply 120 via the external connector 154.

[0014] The electronic control unit 70 is configured as a microprocessor centered around a CPU 72. The electronic control unit 70 receives, for example, the rotational position θm of the rotor of the motor 32 from the rotational position detection sensor 32a, the voltage VB from the voltage sensor 36a, the current IB from the current sensor 36b, the voltage VH of the high-voltage side capacitor 46 from the voltage sensor 46a, the voltage VL of the low-voltage side capacitor 48 from the voltage sensor 48a, and the charging voltage Vchg from the voltage sensor 50a. The electronic control unit 70 is also connected to a connection line 58 connected to a vehicle-side inlet 54 and a lid signal line 62 from a lid sensor 56. Since the electronic control unit 70 also functions as a drive control device for the vehicle, it also receives information necessary for system startup and driving control. For example, the electronic control unit 70 receives a start signal from a start switch 77, a shift position from a shift position sensor (not shown), an accelerator pedal position from an accelerator pedal position sensor, a brake pedal position from a brake pedal position sensor, and vehicle speed from a vehicle speed sensor.

[0015] The electronic control unit 70 outputs, for example, a switching control signal to the transistor of the inverter 34, a switching control signal to the transistor of the boost converter 40, a drive control signal to the system main relay 38, a drive control signal to the charging relay 52, a display signal to a display 78 arranged on the instrument panel in front of the driver's seat, a lighting signal to a ready lamp 79, a switching control signal to the transistor of the DC / DC converter 82, and the like. The electronic control unit 70 communicates with the external DC power supply 120 by connecting the communication line 60 to an external communication line 160.

[0016] Next, a description will be given of the operation of the electrically powered vehicle 20 of this embodiment configured as described above, particularly the operation when charging of the battery 36 with power from the external DC power supply 120 is completed. Fig. 2 is a flowchart showing an example of post-charge processing executed by the electronic control unit 70 when charging of the battery 36 with power from the external DC power supply 120 is completed.

[0017] When the charging end process is executed, the electronic control unit 70 first performs a welding abnormality diagnosis to determine whether or not a welding abnormality has occurred in the charging relay 52 while the external DC power supply 120 is connected (step S100), and determines whether or not there is a possibility of a welding abnormality in the charging relay 52 (step S110). The welding abnormality diagnosis is performed using the charging voltage Vchg detected by the voltage sensor 50a with the charging relay 52 turned off and the system main relay 38 turned on. Specifically, if the charging voltage Vchg detected by the voltage sensor 50a when the charging relay 52 is turned off is less than a threshold, it is diagnosed that there is no welding abnormality in the charging relay 52. ​​However, if the charging voltage Vchg is equal to or greater than the threshold, it is diagnosed that there is a possibility of a welding abnormality in the charging relay 52. ​​The latter possibility of a welding abnormality in the charging relay 52 also occurs when voltage is applied from the external DC power supply 120. If the welding abnormality diagnosis determines that no welding abnormality has occurred in charging relay 52, it is determined in step S110 that there is no possibility of a welding abnormality in charging relay 52, the system is shut down (step S170), ready-on is permitted (step S180), and this process ends. In this case, the ready-on state is immediately established when the user subsequently turns on start switch 77.

[0018] If it is determined in step S110 that there is a possibility of a welding abnormality in the charging relay 52, the system is shut down (step S120) and waits for a predetermined condition to be met (step S130). While waiting for this predetermined condition to be met, the electronic control unit 70 enters sleep mode. The predetermined condition may be a condition in which the connection between the vehicle-side inlet 54 and the external connector 154 of the external DC power supply 120 is released, a condition in which a predetermined time has elapsed since the connection between the vehicle-side inlet 54 and the external connector 154 was released, a condition in which a lid (not shown) that covers the vehicle-side inlet 54 from the outside is completely closed based on a lid signal line 62 from a lid sensor 56 attached to the vehicle-side inlet 54, or a condition in which a predetermined time has elapsed since the lid was completely closed, etc.

[0019] When the predetermined condition is met, the system is started (step S140), and a welding abnormality diagnosis of charging relay 52 is performed (step S150), and it is determined whether a welding abnormality has occurred (step S160). In this case, the welding abnormality diagnosis is performed using the charging voltage Vchg detected by voltage sensor 50a with system main relay 38 turned on and charging relay 52 turned off while the connection between vehicle inlet 54 and external connector 154 of external DC power supply 120 is disconnected. Specifically, when the charging relay 52 is turned off and only the positive relay DCRB is turned on, if the charging voltage Vchg detected by the voltage sensor 50a is equal to or greater than a threshold, a diagnosis is made that a welding abnormality has occurred in the negative relay DCRG. When the charging relay 52 is turned off and only the negative relay DCRG is turned on, if the charging voltage Vchg detected by the voltage sensor 50a is equal to or greater than a threshold, a diagnosis is made that a welding abnormality has occurred in the positive relay DCRB. When both charging voltages Vchg are less than the threshold, a diagnosis is made that a welding abnormality has not occurred in the charging relay 52. ​​If it is determined in step S160 that a welding abnormality has not occurred in the charging relay 52, the system is shut down (step S170), a ready-on state is permitted (step S180), and this process is terminated. In this case, the system immediately enters the ready-on state when the user subsequently turns on the start switch 77.

[0020] If it is determined in step S160 that a welding abnormality has occurred in charging relay 52, a process is performed to notify the user of the welding abnormality in charging relay 52 (step S190), the system is shut down (step S200), and this process ends. In this case, when the user subsequently turns on start switch 77, the user is notified by a message on display 78 or by a voice output that the ready-on state cannot be achieved due to the welding abnormality in charging relay 52.

[0021] In the electric vehicle 20 according to the embodiment described above, when charging of the battery 36 using power from the external DC power supply 120 is completed, the charging relay 52 is diagnosed for a welding abnormality while the external DC power supply 120 is connected. If this diagnosis determines that there is a possibility that there is a welding abnormality in the charging relay 52, the system is shut down and then starts up in sleep mode until a predetermined condition is met, and the charging relay 52 is diagnosed for a welding abnormality while the external DC power supply 120 is not connected. This makes it possible to more reliably diagnose whether there is a possibility that there is a welding abnormality in the charging relay 52 due to the connection of the external DC power supply 120. As a result, it is possible to prevent an erroneous diagnosis of a welding abnormality in the charging relay 52 due to the connection of the external DC power supply 120.

[0022] In the electric vehicle 20 of the embodiment, the battery 36 is charged using DC power from the external DC power supply 120. However, the battery 36 may also be charged using AC power from an external AC power supply. In this case, a power conversion device that converts AC power into DC power of an arbitrary voltage may be incorporated into the charging power line 50.

[0023] In the electric vehicle 20 of the embodiment, a battery 36 is used as the power storage device, but any device capable of storing electricity may be used, such as a capacitor. In the electric vehicle 20 of the embodiment, a boost converter 40 is provided, but the boost converter 40 may not be provided.

[0024] In the embodiment, the electric vehicle 20 is provided with a motor 32. However, the electric vehicle 20 may be provided with a hybrid vehicle that includes an engine in addition to the motor 32, or may be provided with a fuel cell.

[0025] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0026] The present disclosure is applicable to the electric vehicle manufacturing industry and the like. [Explanation of symbols]

[0027] 20 electric vehicle, 22a, 22b drive wheels, 24 differential gear, 26 drive shaft, 32 motor, 34 inverter, 36 battery, 38 system main relay, 40 boost converter, 42 high-voltage power line, 44 low-voltage power line, 50 charging power line, 52 charging relay, 54 vehicle inlet, 56 lid sensor, 58 connection line, 70 electronic control unit, 120 external DC power supply device, 150 external charging power line, 154 external connector, 158 external connection line, 160 external communication line, DCRB positive side relay, DCRG negative side relay.

Claims

[Claim 1] a drive unit that outputs power for running; a power storage device that supplies power to the drive device; a system main relay attached to a drive power line connecting the power storage device and the drive device; a vehicle-side connection portion that is connected to an external-side connection portion from an external power supply device outside the vehicle; a charging relay attached to a charging power line connecting the drive power line between the system main relay and the drive device and the vehicle-side connection unit; a control device that controls charging of the power storage device with electric power from the external power supply device and performs a first abnormality diagnosis that diagnoses a welding abnormality of the charging relay while the external power supply device is connected immediately after charging of the power storage device with electric power from the external power supply device is completed; An electric vehicle comprising: When the control device diagnoses that there is a possibility of a welding abnormality as a result of the first abnormality diagnosis, the control device shuts down the system upon completion of the abnormality diagnosis and puts the system into a sleep mode, and thereafter, when a predetermined condition is met, starts up the system and performs a second abnormality diagnosis in which the control device diagnoses whether there is a welding abnormality in the charging relay while the external power supply device is not connected. An electric vehicle characterized by:

Images