vehicle

Abstract

When driving a relay using the output voltage of a boost circuit, it detects whether the relay is properly connected. [Solution] Relays SMRB and SMRG are driven by the output voltage Vd of a boost circuit that increases the voltage of the auxiliary battery. The boost circuit increases the voltage while the boost command is ON (time t0~t8). When the output voltage Vd is greater than or equal to threshold A, the voltage flag Fv is set to 1. Once flag Fv is set to "1", the connection commands for SMRB and SMRG are sequentially set to ON commands. When SMRB is ON and flag Fv is 1, counter CB is incremented, and when SMRG is ON and flag Fv is 1, counter CG is incremented. When flag Fv becomes 0, counters CB and CG are reset. When counter CB is greater than or equal to threshold T, the normal flag Fb becomes 1, and when counter CG is greater than or equal to threshold T, the normal flag Fg becomes 1.

Description

Technical Field

[0001] This disclosure relates to vehicles.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2024-8531 (Patent Document 1) discloses a vehicle equipped with a power storage device (battery). In this vehicle, the DC power of the battery is converted into AC power by a power control unit to drive a driving motor. The battery and the power control unit are electrically connected via a system main relay. When the system main relay is in the connected state, power can be supplied to the driving motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0007] The vehicle described herein comprises a drive battery, a drive motor powered by the drive battery, a relay provided on the power line connecting the drive battery and the drive motor, an auxiliary battery, a boost circuit for boosting the voltage of the auxiliary battery, and a control device. The relay is configured to be driven and connected by the output voltage of the boost circuit. When connecting the relay, the control device determines that the relay has been connected correctly if the output voltage of the boost circuit remains above a predetermined value for a first predetermined time.

[0008] In this configuration, the relay is driven and connected by the output voltage of a boost circuit that increases the voltage of the auxiliary battery. The relay is properly connected when a voltage of a predetermined value or higher is supplied for a predetermined period of time or longer. When connecting the relay, the control device determines that the relay is properly connected if the output voltage of the boost circuit remains above the predetermined value for a predetermined period of time or longer. Therefore, when driving the relay using the output voltage of the boost circuit, it is possible to detect that the relay is properly connected.

[0009] Preferably, the control device may be configured to notify that the relay is not properly connected if it is determined that the relay is not properly connected.

[0010] In this configuration, when connecting a relay, if the output voltage of the boost circuit does not remain above a predetermined value for a first predetermined time, and the relay is not determined to be properly connected, the control device will notify that there is a connection abnormality. The notification may be an alarm. Alternatively, the notification may be a diagnostic (self-diagnosis function) that stores a fault code (DCT (Diagnostic Trouble Code)) and notifies that there is a relay connection abnormality during diagnosis.

[0011] Preferably, when connecting the relay, the control device increases the voltage of the auxiliary battery using a boost circuit for a second predetermined time that is longer than the first predetermined time. If the control device does not determine that the relay is properly connected, it may increase the voltage of the auxiliary battery using the boost circuit for a third predetermined time that follows the second predetermined time.

[0012] In this configuration, if the control device determines that the relay is not properly connected, it extends the voltage boost by the boost circuit for a third predetermined time. Since the voltage boost by the boost circuit is extended, the opportunities for the relay to connect properly increase. Because the extension of the voltage boost by the boost circuit is for the third predetermined time, it is possible to suppress excessive heat generation in the boost circuit.

[0013] Preferably, the relay includes a first relay installed on the positive terminal of the power line and a second relay installed on the negative terminal of the power line. The control device controls the connection of the first relay, and then the second relay. When the voltage boosting is completed after a second predetermined time, the control device determines whether the first and second relays are properly connected. If it is determined that the relays are not properly connected, the control device may boost the voltage of the auxiliary battery using the boost circuit for a third predetermined time.

[0014] In this configuration, the control device controls the connection of the first relay on the positive terminal wire, and then the second relay on the negative terminal wire. When the voltage boosting is completed after a second predetermined time, the control device determines whether the first and second relays are properly connected. If the control device determines that the relays are not properly connected, it extends the voltage boosting of the boost circuit for a third predetermined time. Because multiple relays are connected consecutively by the voltage boosting during the second predetermined period, the voltage boosting waiting time and heat generation can be reduced compared to when the voltage boosting is performed each time the first and second relays are connected. When the control device determines that the relays are not properly connected, it extends the voltage boosting of the boost circuit, increasing the opportunities for the relays to be properly connected.

[0015] Preferably, when the relay is not determined to be normally connected during the third predetermined time, the control device notifies that the relay is abnormally connected.

[0016] According to this configuration, even after the voltage boost of the boost circuit ends, if the relay is not determined to be normally connected, it notifies that there is an abnormal connection. Therefore, the reliability of the abnormal connection can be increased.

Effect of the Invention

[0017] According to the present disclosure, when driving a relay using the output voltage of a boost circuit, it is possible to detect that the relay is properly connected.

Brief Description of the Drawings

[0018] [Figure 1] It is an overall configuration diagram of a vehicle according to an embodiment of the present disclosure. [Figure 2] It is a diagram for explaining the operation of the SMR. [Figure 3] It is a flowchart showing an example of the boost control process executed by the battery ECU. [Figure 4] It is a flowchart showing an example of the normal determination process executed by the battery ECU. [Figure 5] It is a flowchart showing the process of extension control in boost control. [Figure 6] It is a time chart at the time of connecting the SMR.

Mode for Carrying Out the Invention

[0019] 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 their description will not be repeated.

[0020] FIG. 1 is an overall configuration diagram of a vehicle 1 according to an embodiment of the present disclosure. In the following, the case where the vehicle 1 is a battery electric vehicle (BEV) will be typically described. However, the vehicle of the present disclosure may be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV).

[0021] Referring to FIG. 1, the vehicle 1 includes a battery 10, a power control unit (hereinafter also referred to as "PCU (Power Control Unit)") 20, a motor generator (hereinafter also referred to as "MG (Motor Generator)") 30, drive wheels 40, and a system main relay (SMR) 50. The vehicle 1 also includes a smoothing capacitor 55, a battery ECU (Electronic Control Unit) 60, and a vehicle ECU 70.

[0022] The battery 10 is a rechargeable power storage element. The battery 10 is, for example, a battery pack composed of a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The battery 10 is configured to be charged (externally charged) from a charging facility not shown. The battery 10 corresponds to an example of the drive battery of the present disclosure.

[0023] The battery 10 stores electric power for driving the MG 30 and can supply electric power to the MG 30 through the PCU 20. Also, the battery 10 is charged by receiving the generated electric power through the PCU 20 when the MG 30 generates electric power.

[0024] The PCU 20 performs bidirectional power conversion between the battery 10 and the MG 30 in accordance with a control signal from the battery ECU 60 or the vehicle ECU 70. The PCU 20 is configured to include, for example, an inverter for driving the MG 30 and a converter for boosting the DC voltage supplied to the inverter to be higher than the output voltage of the battery 10.

[0025] MG30 is, for example, a three-phase AC synchronous motor with permanent magnets embedded in the rotor. MG30 is driven by PCU20 to generate rotational driving force, which is transmitted to the drive wheels 40. On the other hand, during braking of vehicle 1 or when acceleration is reduced on a downhill slope, MG30 operates as a generator and performs regenerative power generation. The power generated by MG30 is supplied to battery 10 through PCU20. MG30 corresponds to the "driving motor" in this disclosure.

[0026] The smoothing capacitor 55 is electrically connected between the positive electrode wire PL and the negative electrode wire NL, and smooths the AC component of the voltage fluctuation between the positive electrode wire PL and the negative electrode wire NL. The smoothing capacitor 55 may also be included in the PCU 20.

[0027] SMR50 includes relays SMRB, SMRG, and SMRP, and a limiting resistor 52. Relay SMRB is provided on the positive terminal wire PL connecting the positive terminal of battery 10 to PCU 20. Relay SMRG is provided on the negative terminal wire NL connecting the negative terminal of battery 10 to PCU 20. Relay SMRP and limiting resistor 52 are connected in series and connected in parallel to relay SMRG. Relay SMRB corresponds to the “first relay” of this disclosure, and relay SMRG corresponds to the “second relay” of this disclosure.

[0028] In this embodiment, each relay is a mechanical relay in which a movable contact moves and closes due to the electromagnetic force generated by energizing a solenoid (coil). Note that a contactless relay (semiconductor relay) may be used instead of the SMRP relay. Each relay is turned on (ON) or off (OFF) in response to a control signal from the battery ECU 60.

[0029] The relay SMRP and limiting resistor 52 form a pre-charge circuit to reduce the inrush current that flows when the SMR50 is turned on. Specifically, when the SMR50 is turned on, relay SMRP is turned on after relay SMRB is turned on but before relay SMRG is turned on, and the smoothing capacitor 55 is pre-charged while the current is limited by the limiting resistor 52. This reduces the inrush current that flows from the battery 10 to the smoothing capacitor 55 when the SMR50 is turned on.

[0030] The positive terminal PL and negative terminal NL are connected to an auxiliary battery 100 via a DC / DC converter 80. The auxiliary battery 100 is used as a power source for the vehicle 1's auxiliary equipment 200, such as electric power steering. In this embodiment, the output voltage (rated voltage) of the auxiliary battery 100 is 12[V]. The DC / DC converter 80 charges the auxiliary battery 100 with power from the battery 10. The battery ECU 60 controls the DC / DC converter 80 so that the State of Charge (SOC) of the auxiliary battery 100 is maintained within a predetermined range.

[0031] The output voltage of the auxiliary battery 100 is boosted by the boost circuit 90. Relays SMRB and SMRG are driven when the output voltage of the boost circuit 90 is applied (energized). Relay SMRP is driven when the output voltage of the auxiliary battery 100 is applied (energized). Semiconductor switches (IPDs (Intelligent Power Devices)) 60 are provided between the boost circuit 90 and relays SMRB and SMRG, and between the auxiliary battery 100 and relay SMRP. When the corresponding IPD 60 is turned ON (connected), relays SMRB, SMRG, and SMRP are energized.

[0032] Both the battery ECU 60 and the vehicle ECU 70 consist of a CPU (Central Processing Unit), memory (ROM (Read Only Memory) and RAM (Random Access Memory)), and input / output ports for inputting and outputting various signals (neither is shown in the diagram). The battery ECU 60 and the vehicle ECU 70 are able to communicate with each other, for example, via a CAN (Controller Area Network).

[0033] When the power switch (start switch), not shown, is turned ON, the vehicle ECU 70 executes a process (startup process) to put vehicle 1 into a Ready-ON state. In this process, the battery ECU 60 receives a command from the vehicle ECU 70 and turns the SMR 50 ON. When the power switch is turned OFF, the vehicle ECU 70 executes a process (stop process) to put vehicle 1 into a Ready-OFF state. In this process, the battery ECU 60 receives a command from the vehicle ECU 70 and turns the SMR 50 OFF. The battery ECU 60 and the vehicle ECU 70 correspond to an example of a "control device" in this disclosure.

[0034] Figure 2 illustrates the operation of the relay SMRB. In Figure 2, the vertical axis represents the force acting on the movable core r1, and the horizontal axis represents the stroke amount of the movable core r1. When the solenoid (coil) r2 is energized, the magnetic field generated by the solenoid r2 attracts the movable core r1 to the fixed core r3. The attractive force of the movable core r1 is approximately proportional to the magnitude of the voltage (current) applied to the solenoid r2 and approximately inversely proportional to the square of the distance between the movable core r1 and the fixed core r3.

[0035] Referring to Figure 2, when a voltage is applied to the solenoid r2 of the relay SMRB, and an attractive force exceeding the preload F1 (and static friction force) of the return spring s1 is generated on the movable core r1, the movable contact mc moves from the disconnected state (A) to the contact state (B). In the contact state (B), the movable contact mc contacts the fixed contacts fc, fc, and the relay SMRB becomes connected. If the voltage applied to the solenoid r2 is sufficiently high, as shown by the dashed line in Figure 2, the attractive force on the movable core r1 becomes greater than the sum of the reaction force of the return spring s1 and the preload of the compression spring s2 F2, and the movable core r1 moves to the fully connected state (C). In the fully connected state (C), the movable core r1 contacts the fixed core r3, compressing the contact spring s2. The reaction force applied to the movable core r1 is the sum of the reaction force of the return spring s1 and the reaction force of the contact spring s2, as shown by the solid line in Figure 2, which is F3. After the relay SMRB is fully connected (C), the voltage applied to the solenoid r2 can be reduced to a voltage that maintains the attractive force of the movable core r1 at value F3.

[0036] When the voltage applied to solenoid r2 is low, the attractive force of the movable core r1 may be less than the sum of the reaction force of the return spring s1 and the preload of the compression spring s2, F2, in the contact state (B), as shown by the dashed line in Figure 2. In this case, the movable core r1 stops in the contact state (B). When the movable core r1 is stopped in the contact state (B), even if the current to solenoid r2 is stopped, the reaction force of the return spring s1 is small, so the movable core r1 may not move due to friction, etc., and the circuit breaker may not be turned off (A).

[0037] Relay SMRG has the same configuration and operation as relay SMRB. Relay SMRP also has a similar configuration, but is smaller in size than relay SMRB, and its movable core can move to a fully connected state even with a lower voltage applied to the solenoid compared to relay SMRB.

[0038] In this embodiment, when connecting relays SMRB and SMRG, it is determined that relays SMRB and SMRG are properly connected if the output voltage of the boost circuit 90 remains above a predetermined value for a predetermined period of time. This allows for detection that relays SMRB and SMRG are properly connected.

[0039] Figure 3 is a flowchart illustrating an example of the boost control process performed by the battery ECU 60. This flowchart starts when the power switch (not shown) is turned ON and the vehicle 1 startup process is executed, and is repeated at predetermined intervals. It ends when the boost stop in step 15 (hereinafter, steps are abbreviated as "S") is processed, or when the extended control in S19 is completed. In the case of a configuration where the SMR 50 needs to be connected when the battery 10 is externally charged, this process is also executed when external charging of the battery 10 is started.

[0040] First, in S10, it is determined whether the boost command is ON or OFF. When the startup process of vehicle 1 is executed, the vehicle ECU 70 outputs a boost command and an ON command for the SMR50 in order to connect the SMR50. When the vehicle ECU 70 outputs a boost command, the boost command is turned ON. If the boost command is ON, it is determined to be OK in S10 and the process proceeds to S11. If the boost command is OFF, it is determined to be OFF in S10 and the process proceeds to S14.

[0041] In S11, the battery ECU 60 activates the boost circuit 90 to boost the output voltage of the auxiliary battery 100. In the following S12, it is determined whether the output voltage Vd of the boost circuit 90 is greater than or equal to threshold A. The output voltage Vd may be detected by a voltage sensor 5 (see Figure 1) provided on the output side of the boost circuit 90. Threshold A is the voltage that can drive the relays SMRB and SMRG to a fully connected state. For example, threshold A may be 14[V]. Threshold A corresponds to the “predetermined value” in this disclosure. If the output voltage Vd exceeds threshold A, it is determined to be positive in S12 and the process proceeds to S13. If the output voltage Vd is less than threshold A, it is determined to be negative and the process proceeds to S16.

[0042] In S13, the voltage flag Fv is set to 1, and the routine ends. In S16, the voltage flag Fv is set to 0, and the routine ends.

[0043] In S14, it is determined whether the boost command has switched from ON to OFF. After outputting the boost command, the vehicle ECU 70 stops outputting the boost command after a set time has elapsed. When the output of the boost command stops, the boost command becomes OFF. The boost command remains ON for the set time. The set time is sufficient time to connect the SMR50 (relays SMRB, SMRP, SMRG), including the pre-charge period by relay SMRP, and is set in advance by experimentation or the like. The set time corresponds to the "second predetermined time" in this disclosure.

[0044] In this process, if the boost command switches from ON to OFF, it is judged positively in S14 and proceeds to S17. If the boost command is OFF (if the boost command switched from ON to OFF before the previous process), it is judged negative and proceeds to S15.

[0045] In S17, it is determined whether the connections of relays SMRB and SMRG are normal. Whether the connections are normal is determined by the normal flags Fb and Fg, which are set in the normal determination process described later (see Figure 4). The normal flag Fb is set to 1 when the connection of relay SMRB is normal and to 0 when it is abnormal. The normal flag Fg is set to 1 when the connection of relay SMRG is normal and to 0 when it is abnormal. In S17, if both the normal flags Fb and Fg are 1, the determination is positive and the process proceeds to S15. If at least one of the normal flags Fb and Fg is 0, the determination is negative and the process proceeds to S18.

[0046] In S15, the boost circuit 90 is stopped and the boosting is halted, then the process proceeds to S16. In S18, temporary error processing is performed, and then the process proceeds to S19. Temporary error processing involves the battery ECU 60 notifying the vehicle ECU 70 that the extended control in S19 will be executed. Upon receiving this notification, the vehicle ECU 70 may display, for example, "System startup in progress" on the display of the HMI (Human Machine Interface) device 71.

[0047] In S19, the battery ECU60 performs extension control (Figure 5). Once the extension control is complete, the current routine terminates. Details of the extension control will be described later.

[0048] Figure 4 is a flowchart showing an example of the normal status determination process performed by the battery ECU 60. This flowchart is repeated at predetermined intervals when the boost control shown in Figure 3 is being executed. This normal status determination process is performed for relays SMRB and SMRG. Since the process is the same, the process for relay SMRG will be explained.

[0049] In S20, the battery ECU 60 determines whether relay SMRG is ON or OFF. During the startup process, after the boost circuit 90 is activated, once the voltage flag Fv is set to "1", the battery ECU 60 outputs ON commands to relays SMRB, SMRP, and SMRG in that order. The battery ECU 60 then sequentially turns ON the corresponding IPD60 according to the ON commands, energizing relays SMRB, SMRP, and SMRG in that order. If the power switch (not shown) is turned OFF, the vehicle ECU 70 outputs an OFF command (shutdown command) for SMR50 to the battery ECU 60. Upon receiving the OFF command for SMR50, the battery ECU 60 turns OFF all IPD60, cuts off power to relays SMRB, SMRP, and SMRG, and puts SMR50 into a shut-off state.

[0050] If the output voltage of the boost circuit 90 is applied to the relay SMRG and the relay SMRG is ON, the result is positive in S20 and the process proceeds to S21. If the relay SMRG is OFF (not energized), the result is negative and the process proceeds to S26. Note that the determination of whether the relay SMRG is ON or not may be based on the ON command of the relay SMRG, and considering the response delay of the relay SMRG, the determination of whether it is ON may be made after a certain period of time has elapsed since the ON command was output.

[0051] In S21, the battery ECU 60 determines whether the voltage flag Fv is 1 or not. If the voltage flag Fv is 1, the determination is affirmative and the process proceeds to S22; if the voltage flag Fv is 0, the determination is negative and the process proceeds to S27.

[0052] In S22, the battery ECU60 determines whether the normal flag Fg is 1 or not. The normal flag Fg is set to 1 in the process of S25, which will be described later. If the normal flag Fg is 0, it is determined to be negative and the process proceeds to S23. If the normal flag Fg is 1, it is determined to be positive and the routine ends.

[0053] In S23, the counter CG is incremented, and then the process proceeds to S24. In S24, it is determined whether the counter CG is greater than or equal to the threshold T. If the counter CG is greater than or equal to the threshold T, the result is positive, and the process proceeds to S25. When relay SMRG is ON, if the voltage flag Fv is 1 (the output voltage Vd of the boost circuit 90 is greater than or equal to the threshold A) continues for a time corresponding to the threshold T, the result is positive in S24, and the process proceeds to S25. The threshold T is the value corresponding to the "first predetermined time" in this disclosure. If the counter CG is less than the threshold T, the result is negative, and the process terminates.

[0054] In S25, the normal flag Fg is set to 1, and then the routine ends. In S26, it is determined whether the normal flag Fg is 1 or not. If the normal flag Fg is 1, the result is positive, and the routine ends. If the normal flag Fg is 0, the result is negative, and the process proceeds to S27.

[0055] In S27, the normal flag Fg is set to 0 (or remains 0 if it is 0), and the counter CG is reset to 0 before the routine ends.

[0056] The normal determination process in Figure 3 is also performed for the relay SMRB. In the normal determination process for the relay SMRB, as shown in the table in Figure 3, "relay SMRG" in S20 is replaced with "relay SMRB", "Fg" in S22, 25, 26, and 27 is replaced with "Fb", and "counter CG" in S23, 24, and 27 is replaced with "counter CB".

[0057] In the normal determination process, when relay SMRG is ON, if the voltage flag Fv remains at 1 (the output voltage Vd of the boost circuit 90 is greater than or equal to threshold A) for a time corresponding to threshold T, the normal flag Fg is set to 1 in S25. Also, when relay SMRB is ON, if the voltage flag Fv remains at 1 (the output voltage Vd of the boost circuit 90 is greater than or equal to threshold A) for a time corresponding to threshold T, the normal flag Fb is set to 1 in S25.

[0058] Figure 5 is a flowchart showing the processing of extension control (S19) in boost control (Figure 3). First, the battery ECU 60 starts timer E in S190 and then proceeds to S191. In S191, it is determined whether timer E is greater than or equal to the threshold eT. The threshold eT corresponds to the "third predetermined time" in this disclosure. If timer E is less than the threshold eT, it is determined to be negative and proceeds to S192. If timer E is greater than or equal to the threshold eT, it is determined to be positive and proceeds to S196.

[0059] In S192, the boost operation of the boost circuit 90 continues, and the process proceeds to S193. In S193, it is determined whether the output voltage Vd of the boost circuit 90 is greater than or equal to threshold A. If the output voltage Vd is greater than or equal to threshold A, the process is affirmed, and the process proceeds to S194, where the voltage flag Fv is set to 1, and then the process returns to S191. If the output voltage Vd is less than threshold A, the process is denied, and the process proceeds to S195, where the voltage flag Fv is set to 0, and then the process returns to S191.

[0060] In S196, the boosting of the boost circuit 90 is stopped, and the process proceeds to S197. In S197, it is determined whether the connections of relays SMRB and SMRG are normal. Whether the connections are normal is determined by the normal flags Fb and Fg set in the normal determination process (see Figure 4), similar to S17 (Figure 3). If both normal flags Fb and Fg are 1, the result is positive, and the process proceeds to S199. If at least one of normal flags Fb and Fg is 0, the result is negative, and the process proceeds to S198.

[0061] In S198, error processing is performed. Error processing involves the battery ECU 60 notifying the vehicle ECU 70 that the SMR 50 could not be connected properly. Upon receiving this notification, the vehicle ECU 70 displays, for example, "SMR is faulty" on the display of the HMI (Human Machine Interface) device 71. The vehicle ECU 70 also illuminates the MIL (Malfunction Indicator Lamp) 72 and writes a diagnostic DCT to memory. The DCT may be a code that identifies the relay that malfunctioned (could not be connected properly).

[0062] In S199, a temporary malfunction is detected and the system is stopped. This temporary malfunction notification sends a message from the battery ECU60 to the vehicle ECU70 indicating that the SMR50 has been successfully connected. Upon receiving this notification, the vehicle ECU70 stops displaying messages on the HMI71, such as "System startup in progress."

[0063] Figure 6 is a time chart for connecting the SMR50. When the power switch (start switch), which is not shown, is turned ON, the startup process begins, and at time t0, the boost command changes from OFF to ON. When the boost command is ON, the boost circuit 90 operates, and the output voltage Vd increases. At time t1, the output voltage Vd becomes greater than or equal to threshold A, and the voltage flag Fv is set to 1. Once the voltage flag Fv becomes "1", connection commands are turned ON in the order of relay SMRB, relay SMRP, and relay SMRG. The command to relay SMRB changes from an OFF command to an ON command, and after a response delay, at time t2, when relay SMRB turns ON, the counter CB starts counting. At time t3, when the counter CB becomes greater than or equal to threshold T, the normal flag Fb is set to 1. The period from time t2 to time t3 corresponds to the "first predetermined time" in this disclosure.

[0064] Next, before the command to relay SMRG changes from OFF to ON, the command to relay SMRP changes from OFF to ON. When relay SMRP turns ON, the smoothing capacitor 55 is precharged, and after relay SMRG turns ON, relay SMRP turns OFF.

[0065] Subsequently, at time t4, the command to relay SMRG changes from an OFF command to an ON command. After a response delay, at time t5, when relay SMRG turns ON, the counter CG starts counting. For example, when the auxiliary equipment 200 consumes power from the auxiliary battery 100, and at time t6, the output voltage Vd of the boost circuit 90 falls below threshold A, the voltage flag Fv is set to 0. When the voltage flag Fv is set to 0, the counter CG is reset to 0.

[0066] Subsequently, at time t7, when the output voltage Vd of the boost circuit 90 becomes greater than or equal to threshold A, the voltage flag Fv is set to 1, and the counter CG resumes counting. At time t8, the boost command is turned OFF by a command from the vehicle ECU 70. The period from time t0 to time t8 corresponds to the "second predetermined time" in this disclosure. At time t8, since the counter CG is less than threshold T, extension control is executed. Extension control is a control that maintains the boosting of the boost circuit 90 without stopping, even when the boost command is OFF. In this embodiment, the boosting of the output voltage of the auxiliary battery 100 by the boost circuit 90 is extended from time t8 to time t10. Then, at time t9, the counter CG becomes greater than or equal to threshold T, and the normal flag Fg is set to 1. At time t10, the boosting of the boost circuit 90 stops. The period from time t8 to time t10 corresponds to threshold eT (S191).

[0067] According to this embodiment, relay SMRB, provided on the positive terminal of the power line, and relay SMRG, provided on the negative terminal of the power line, are driven and connected by the output voltage Vd of a boost circuit 90 that boosts the voltage of the auxiliary battery 100. The boost circuit 90 boosts the voltage of the auxiliary battery 100 from time t0 to time t8 (second predetermined time). The battery ECU 60 connects relay SMRB and relay SMRG in this order. When connecting relay SMRB, the battery ECU 60 determines that relay SMRB is properly connected if the output voltage Vd of the boost circuit 90 remains at or above threshold A for a first predetermined time (when counter CB becomes at or above threshold T). When connecting relay SMRG, the battery ECU 60 determines that relay SMRG is properly connected if the output voltage Vd of the boost circuit 90 remains at or above threshold A for a first predetermined time (when counter CG becomes at or above threshold T). Therefore, when driving the relay using the output voltage of the boost circuit 90, it is possible to detect whether the relay is properly connected.

[0068] According to this embodiment, at time t8 when the boost command changes from ON to OFF (when the boosting for the second predetermined time is completed), the battery ECU 60 determines whether relays SMRB and SMRG are properly connected. If the battery ECU 60 determines that the relays are not properly connected, it extends the boosting of the boost circuit 90 until timer E reaches the threshold eT (for the third predetermined time). Since multiple relays are connected consecutively by the boosting from time t0 to time t8 (the second predetermined time), the boosting waiting time of the boost circuit 90 can be reduced and the amount of heat generated can be reduced compared to when the boost circuit 90 is activated each time an ON command is issued for relays SMRB and SMRG. In addition, if the relays are not properly connected, the boosting by the boost circuit 90 is extended until timer E reaches the threshold eT, which increases the chances of the relays being properly connected.

[0069] In the above embodiment, the battery ECU 60 performed extension control if it was determined that relays SMRB and SMRG were not properly connected at time t8 when the boost command changed from ON to OFF (when the boosting by the second predetermined time was completed) (Figure 3: When a positive determination was made in S17, the extension control in S19 was performed). However, the extension control may be omitted. In this case, the "temporary abnormality action" in S18 (Figure 3) may be replaced with the "abnormality processing" in S198 (Figure 5).

[0070] In the above embodiment, it was determined whether relay SMRB and relay SMRG were properly connected. However, it is also possible to determine whether only relay SMRG, which is connected later, is properly connected. (The determination of relay SMRB is not required.) When the connection command for relay SMRG changes from an OFF command to an ON command, relay SMRB is already under an ON command. Therefore, if relay SMRG is properly connected, there is a high probability that relay SMRB is also properly connected.

[0071] In the above embodiment, a configuration in which the relay SMRP is driven by the output voltage of the boost circuit 90 may be adopted. In this case, the relay SMRP may also be configured to determine whether or not it is properly connected, similar to the relays SMRB and SMRG.

[0072] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention 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]

[0073] 1 Vehicle, 5 Voltage sensor, 6 IPD, 10 Battery, 20 PCU, 30 MG, 40 Drive wheels, 50 SMR, SMRB, SMRP, SMRG Relay, 52 Limiting resistor, 55 Smoothing capacitor, 60 Battery ECU, 70 Vehicle ECU, 71 HMI device, 72 MIL, 80 DC / DC converter, 90 Boost circuit, 100 Auxiliary battery, 200 Auxiliary equipment, fc Fixed contact, mc Movable contact, NL Negative wire, PL Positive wire, r1 Movable iron core, r2 Solenoid (coil), r3 Fixed iron core, s1 Return spring, s2 Compression spring.

Claims

1. A vehicle comprising a drive battery, a drive motor powered by the power of the drive battery, a relay provided on the power line connecting the drive battery and the drive motor, an auxiliary battery, a boost circuit for boosting the voltage of the auxiliary battery, and a control device, The relay is configured to be driven and connected by the output voltage of the boost circuit. The control device is A vehicle that determines that the relay has been properly connected when the output voltage of the boost circuit remains above a predetermined value for a first predetermined time period while the relay is being connected.

2. The control device is The vehicle according to claim 1, wherein if it is determined that the relay is not properly connected, the vehicle reports that there is a connection problem with the relay.

3. The control device is When connecting the relay, the voltage of the auxiliary battery is increased by the boost circuit for a second predetermined time that is longer than the first predetermined time. The vehicle according to claim 1, wherein, when it is determined that the relay is not properly connected, the voltage of the auxiliary battery is increased by the boost circuit for a third predetermined time following the second predetermined time.

4. The relay includes a first relay provided on the positive terminal of the power line and a second relay provided on the negative terminal of the power line. The control device is The system controls the connection of the first relay, and then the connection of the second relay. When the second predetermined time has elapsed, it is determined whether the first relay and the second relay are properly connected, The vehicle according to claim 3, wherein if it is determined that the relay is not properly connected, the voltage of the auxiliary battery is increased by the boost circuit for a third predetermined time.

5. The control device is The vehicle according to claim 3 or 4, wherein if it is not determined that the relay is properly connected during the third predetermined time, the vehicle reports that the relay is experiencing a connection abnormality.

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