Vehicle contactor failure detection device

Abstract

To provide a contactor failure determination device capable of appropriately determining a failure of a contactor provided in a vehicle.SOLUTION: A vehicle contactor failure determination device is provided with a detection device capable of detecting increase and decrease in a voltage of a second circuit including an external charge device. When an external charge request is issued, first control of closing each external charge contactor is performed, second control of closing a precharge contactor is performed after the execution of the first control, third control of closing a second main contactor is performed after the execution of the second control, and, upon detection by the detection device that the voltage of the second circuit does not increase after the execution of the third control, it is determined that a failure occurs in a state where at least one external charge contactor is opened.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a contactor failure determination device mounted on a vehicle equipped with a plurality of contactors. [Background technology]

[0002] Conventionally, vehicles are equipped with an inverter and a motor, and power is supplied to the motor from a battery via the inverter, and a disconnecting device is provided between a circuit having the inverter and the motor and the battery to disconnect the electrical connection therebetween.

[0003] For example, Patent Document 1 discloses a device in which a battery (the DC power source in Patent Document 1) and a load circuit are electrically connected and disconnected by a plurality of relays. Specifically, in the device of Patent Document 1, a first main relay is disposed between the positive terminal of the battery and the load circuit, a second main relay is disposed between the negative terminal of the battery and the load circuit, and a pre-charge relay and an electrical resistor are disposed in parallel therewith. By providing a device between the battery and the circuit that electrically disconnects them in this way, unnecessary exchange of power between the battery and the circuit can be prevented by controlling the device.

[0004] However, if the above device fails, it will no longer be able to properly connect or disconnect the battery from the circuit. This requires diagnosing whether the above device has failed. In response to this, the device in Patent Document 1 is configured to open the first main relay while the second main relay is closed and the pre-charge relay is open when the vehicle is stopped, determine whether the first main relay has failed based on the voltage in the load circuit that occurs at this time, and then open the second main relay while closing the pre-charge relay, and determine whether the second main relay has failed based on the voltage in the load circuit that occurs at this time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4572168 Summary of the Invention [Problem to be solved by the invention]

[0006] Here, vehicles equipped with a motor as a drive source, etc., may be equipped with a device that can charge the battery from a power source outside the vehicle, i.e., an external charging device that connects the external power source to the battery and supplies the output power of the power source to the battery. In this case, it is desirable to provide a contactor that can make and break the electrical connection between the external charging device and a circuit connected to it so as to prevent unnecessary power transfer between the external charging device and other electrical devices or the battery, and to be able to appropriately determine whether the contactor has failed.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a contactor failure determination device for a vehicle that can appropriately determine a failure of a contactor provided in the vehicle. [Means for solving the problem]

[0008] To address the above-mentioned issues, the present inventors have investigated a system in which an external charging device is connected to a circuit connected to a battery via a contactor (external charging contactor), and when a request is made to start external charging to charge the battery from an external power source, the contactor that connects and disconnects the battery from the circuit and the external charging contactor are closed, and a fault in the external charging contactor is determined based on the voltage change on the external charging device side that occurs during this process. However, they found that closing the battery-side contactor and the external charging contactor simultaneously generates a relatively loud noise due to multiple contactors being closed simultaneously. They also investigated a system in which the external charging contactor is closed after the battery-side contactor is closed, but found that this configuration could result in a high inrush current being introduced from the battery to the external charging device side via the circuit. Based on the above findings, the present inventors have invented the following contactor fault determination device that can appropriately determine contactor faults.

[0009] In order to solve the above-mentioned problems, the present invention provides a contactor failure determination device mounted on a vehicle including a battery having a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects and disconnects an electrical connection between one of the positive and negative terminals and the first circuit, a second main contactor that connects and disconnects an electrical connection between the other of the positive and negative terminals and the first circuit, and a pre-charge contactor that is arranged in parallel with the first main contactor and connects and disconnects the electrical connection between the one terminal and the first circuit, the contactor failure determination device comprising: a second circuit that includes an external charging device that can supply power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that connect and disconnect the electrical connections between the first circuit and the negative and positive sides of the second circuit, respectively; a detection device that can detect an increase or decrease in voltage of the second circuit; and a detection device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each external charging contactor, and and a control device that, when a request to start external charging to charge the battery is issued, performs external charging preparation control to change the states of the contactors so that the main contactors and the external charging contactors are closed and the pre-charge contactor is open before power supply from a power source outside the vehicle to the external charging device is started, wherein an electrical resistance between the terminal and the first circuit via the pre-charge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor, and when the external charging preparation control is performed, the control device performs first control to close the external charging contactors, performs second control to close the pre-charge contactors after performing the first control, and performs third control to close the second main contactor after performing the second control, and determines that at least one of the external charging contactors is faulty and in an open state when the detection device detects that the voltage of the second circuit does not increase after performing the third control. and when a second detection device capable of detecting an increase or decrease in the voltage of the first circuit detects that the voltage of the first circuit does not increase after the third control is performed, it is determined that at least one of the pre-charge contactor and the second main contactor is in an open state and has a fault. This is characterized by the above (Claim 1).

[0010] In this device, when the external charging preparation control is performed, that is, during the period from when a request to start external charging is issued until power supply from a power source outside the vehicle to the external charging device is started, the first, second, and third controls are performed to close the external charging contactors, the pre-charge contactor, and the second main contactor in this order. Therefore, while closing the external charging contactors and the second main contactor, it is possible to prevent multiple contactors from being closed simultaneously, thereby preventing occupants from feeling uncomfortable due to the relatively loud noise that would be generated if multiple contactors were closed simultaneously.

[0011] In this device, after one terminal of the battery and the first circuit are connected via the pre-charge contactor in a state of high electrical resistance, the other terminal of the battery and the first circuit are electrically connected via the second main contactor. Therefore, when the battery and the first circuit are electrically connected, a high inrush current from the battery can be prevented from flowing to the first circuit and the second circuit, preventing failure of electrical equipment and the external charging device provided on the first circuit.

[0012] Moreover, this device determines whether or not there is a failure in the external charging contactor based on an increase or decrease in the voltage of the second circuit after the third control is performed, and therefore can appropriately determine whether or not there is a failure in the external charging contactor.

[0013] Specifically, if each external charging contactor is normal, the second circuit and the first circuit are electrically connected by performing the first control. Therefore, if each external charging contactor is normal, the battery and the first circuit are electrically connected by performing the second control and the third control, and the voltage of the second circuit increases. In contrast, if at least one external charging contactor is faulty and in the open state, the electrical connection between the second circuit and the first circuit is interrupted, and the voltage of the first circuit does not increase even when the second control and the third control are performed. Using the above, this device determines that at least one external charging contactor is faulty and in the closed state if the voltage of the second circuit does not increase after performing the third control. Therefore, it is possible to appropriately determine whether an external charging contactor is faulty.

[0014] In addition, in this device, when a second detection device capable of detecting an increase or decrease in the voltage of the first circuit detects that the voltage of the first circuit does not increase after the third control is implemented, the control device determines that at least one of the pre-charge contactor and the second main contactor is in an open state and has failed.

[0015] Here, if both the pre-charge contactor and the second main contactor are normal, when the second and third controls are performed and both are closed, the battery and the first circuit are electrically connected, and the voltage of the first circuit increases. In contrast, if at least one of the pre-charge contactor and the second main contactor is faulty and in the open state, the battery and the first circuit remain electrically disconnected even after the third control is performed, and the voltage of the first circuit does not increase. Taking advantage of this, if the voltage of the first circuit does not increase after the third control is performed, this device determines that at least one of the pre-charge contactor and the second main contactor is faulty and in the open state. Therefore, it is possible to appropriately determine whether these contactors are faulty.

[0016] In the above configuration, preferably, the control device simultaneously closes both of the external charging contactors when the first control is performed (claim 2).

[0017] This configuration makes it possible to avoid the four contactors (two external charging contactors, a pre-charge contactor, and a second main contactor) being closed simultaneously, which would cause a loud noise, while shortening the time required to close the two external charging contactors and thus the time required for fault determination.

[0018] In the above configuration, it is preferable to provide a second detection device capable of detecting an increase or decrease in voltage of the first circuit, and when the second detection device detects that the voltage of the first circuit has increased after the second control is implemented, the control device determines that the second main contactor has failed in the closed state (Claim 3).

[0019] If the second main contactor is normally open, the battery and the first circuit are electrically disconnected even when the second control is performed to close the pre-charge contactor. In contrast, if the second main contactor is in a closed state and faulty, the battery and the first circuit are electrically connected as a result of the second control being performed, and the voltage of the first circuit increases. Taking advantage of this, this configuration determines that the second main contactor is in a closed state and faulty when the voltage of the first circuit increases after the second control is performed. Therefore, it is possible to appropriately determine whether the second main contactor, in addition to the external charging contactor, is faulty.

[0020] In the above configuration, preferably, during the external charging preparation control, the control device performs a fourth control to close the first main contactor after performing the third control, and a fifth control to open the pre-charge contactor after performing the fourth control, and when a second detection device capable of detecting an increase or decrease in voltage of the first circuit detects a decrease in voltage of the first circuit after performing the fifth control, determines that the first main contactor has failed in an open state (see claim 4 ).

[0021] If the first main contactor is normal, the battery and the first circuit are electrically connected via the first main contactor when the fourth control is performed, so the voltage of the first circuit does not decrease even when the pre-charge contactor is opened when the fifth control is performed. In contrast, if the first main contactor is faulty and in an open state, the pre-charge contactor is opened when the fifth control is performed, cutting off the electrical connection between the battery and the first circuit, causing the voltage of the first circuit to decrease. Taking advantage of this, this configuration determines that the first main contactor is faulty and in an open state when the voltage of the first circuit decreases after the fifth control is performed. Therefore, a failure of the first main contactor can be appropriately determined.

[0022] In the above configuration, preferably, the time from when the second control is performed until when the third control is performed is shorter than the time from when the third control is performed until when the fourth control is performed (see claim 5 ).

[0023] In the above configuration, preferably, the time from when the third control is performed until when the fourth control is performed is longer than the time from when the fourth control is performed until when the fifth control is performed (see claim 6 ).

[0024] In the above configuration, preferably, the time from when the fourth control is performed until when the fifth control is performed is longer than the time from when the first control is performed until when the second control is performed (see claim 7 ).

[0025] By setting the time as described above, a contactor failure can be determined more appropriately.

[0026] In the above configuration, preferably, a third detection device capable of detecting a voltage difference between the first circuit and the second circuit is provided, and when the third detection device detects that the voltage of the second circuit is lower than the voltage of the first circuit by a predetermined determination value or more after the start of the external charging, the control device determines that at least one of the external charging contactors has failed in an open state (see claim 8 ).

[0027] By performing the external charging preparation control, the states of the contactors after the start of external charging are such that the main contactors and external charging contactors are closed and the pre-charge contactor is open. As a result, if the external charging contactors are normal, the voltage of the first circuit and the voltage of the second circuit are the same. In contrast, if at least one of the external charging contactors is open and faulty, the voltage of the second circuit is lower than the voltage of the first circuit. Taking advantage of this, this configuration determines that at least one of the external charging contactors is open and faulty if the voltage of the second circuit is lower than the voltage of the first circuit by a predetermined determination value or more after the start of external charging. Therefore, a fault in the external charging contactors can be appropriately determined.

[0028] In the above configuration, preferably, when the external charging is completed, the control device performs a sixth control to open the first main contactor, and when a second detection device capable of detecting an increase or decrease in the voltage of the first circuit detects that the voltage of the first circuit does not decrease after the sixth control is performed, the control device determines that at least one of the first main contactor and the pre-charge contactor is in a closed state and has a fault (see claim 9 ).

[0029] In this configuration, when the sixth control is performed, the first main contactor is opened from a state in which the main contactors and external charging contactors are closed and the pre-charge contactor is open. Therefore, if the first main contactor and pre-charge contactor are normal, the first circuit and the battery are electrically disconnected, and the voltage of the first circuit decreases. In contrast, if at least one of the first main contactor and pre-charge contactor is closed and faulty, the first circuit and the battery remain electrically connected, and the voltage of the first circuit does not decrease. Taking advantage of this, in this configuration, if the voltage of the first circuit does not decrease after the sixth control is performed, it is determined that at least one of the first main contactor and pre-charge contactor is closed and faulty. Therefore, these faults can be appropriately determined.

[0030] In the above configuration, the external charging device may include an AC / DC converter that converts AC current into DC current, converting AC power from an external power source into DC current and supplying it to the battery (see claim 10 ).

[0031] In the above configuration, preferably, the time from when the first control is performed until when the second control is performed is shorter than the time from when the second control is performed until when the third control is performed (see claim 11 ).

[0032] The above time setting allows for more appropriate determination of contactor failure. [Effects of the Invention]

[0033] As described above, the contactor failure determination device for a vehicle of the present invention can appropriately determine whether a contactor provided in the vehicle has failed.

[0034] As described above, the contactor failure determination device for a vehicle of the present invention can appropriately determine whether a contactor provided in the vehicle has failed. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle equipped with a contactor failure determination device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the relationship between the controllers. [Figure 3] FIG. 2 is a block diagram showing a control system related to contactor failure determination. [Figure 4] 10 is a flowchart showing a part of a procedure for determining whether a contactor has failed, which is performed when an external charging request is issued. [Figure 5] 5 is a flowchart showing a continuation of the procedure shown in FIG. 4. [Figure 6] 6 is a flowchart showing a continuation of the procedure shown in FIG. 5. [Figure 7] 10 is a flowchart showing a procedure for determining whether a contactor has failed when external charging is completed. [Figure 8] These figures show the changes in parameters over time when an external charging request is issued, where (a) is a diagram when the contactors are normal, (b) is a diagram of the main voltage when the P-side main contactor is stuck ON, (c) is a diagram of the main voltage when at least one of the P-side main contactor and pre-contactor is stuck OFF, and (d) is a diagram when the N-side main contactor is stuck OFF. [Figure 9] 10A and 10B are diagrams showing the time changes of parameters when an external charging request is issued, where (a) is a diagram showing the case when the contactors are normal, and (b) is a diagram showing the OBC voltage when at least one of the OBC contactors is stuck ON. [Figure 10] FIG. 10 is a diagram showing changes over time in parameters at the end of external charging. DETAILED DESCRIPTION OF THE INVENTION

[0036] (1) Overall vehicle configuration A contactor failure determination device according to an embodiment of the present invention will now be described. Fig. 1 is a diagram schematically showing the configuration of a vehicle 1 equipped with a contactor failure determination device 100 according to this embodiment. The vehicle 1 is, for example, a four-wheeled automobile.

[0037] The vehicle 1 (contactor failure determination device 100) has a high-voltage battery 2, a low-voltage battery 3 having a lower output voltage than the high-voltage battery 2, a high-voltage circuit 30 having a plurality of electrical devices and electrically connected to the high-voltage battery 2, an OBC circuit 40 electrically connected to the high-voltage circuit 30, and a plurality of contactors. The vehicle 1 also has a plurality of controllers including microprocessors and the like that control various parts of the vehicle 1. The high-voltage battery 2 corresponds to the "battery" in the claims, the high-voltage circuit 30 corresponds to the "first circuit" in the claims, and the OBC circuit 40 corresponds to the "second circuit" in the claims.

[0038] (battery) The high-voltage battery 2 has a pair of terminals (positive terminal 2a, negative terminal 2b). In this embodiment, a Li battery (lithium battery) is mounted on the vehicle 1 as the high-voltage battery 2. For example, the high-voltage battery 2 has a plurality of battery modules, each consisting of 12 battery cells connected in two parallel connections and six in series, and these battery modules are connected in series. Also, in this embodiment, a lead battery is mounted on the vehicle 1 as the low-voltage battery 3. For example, the nominal voltage of the high-voltage battery 2 is 24V, and the nominal voltage of the low-voltage battery 3 is 12V.

[0039] (High voltage circuit) The high-voltage circuit 30 includes, as electrical equipment, a motor 4, a generator 5, an inverter 6, a converter 7, a DC / DC converter 8, a PTC heater 9, an electric compressor 10, etc. The high-voltage circuit 30 also has a positive-side high-voltage line 31a that is a positive-side line connected to the positive terminal 2a of the high-voltage battery 2, and an negative-side high-voltage line 31b that is a negative-side line connected to the negative terminal 2b of the high-voltage battery 2. Hereinafter, the positive-side high-voltage line 31a and the negative-side high-voltage line 31b will be referred to collectively as high-voltage lines 31 as appropriate.

[0040] The inverter 6, the converter 7, the DC / DC converter 8, the PTC heater 9, and the electric compressor 10 are each connected to a high-voltage line 31. The motor 4 is connected to the high-voltage line 31 via the inverter 6. The generator 5 is connected to the high-voltage line 31 via the converter 7.

[0041] The motor 4 rotates by receiving a supply of electric power from the high-voltage battery 2. The motor 4 is mounted on the vehicle 1 as a driving source for the vehicle 1, and the output of the motor 4 is transmitted to wheels (not shown) via a driving force transmission device 20.

[0042] The generator 5 is a power generation device for charging the high-voltage battery 2. The vehicle 1 of this embodiment is a series hybrid vehicle. That is, the vehicle 1 is equipped with an engine 22 that drives the generator 5, and the generator 5 is rotated and driven by the engine 22 to generate electricity, and the electricity generated by the generator 5 is supplied to the high-voltage battery 2. The engine 22 is, for example, a rotary engine. The generator 5 is also connected to the wheels via a driving force transmission device 20, so that the vehicle 1 can regenerate energy during deceleration.

[0043] The inverter 6 is a device that converts DC current into AC current, and converts the DC current from the high-voltage battery 2 into AC current and supplies it to the motor 4. The converter 7 is a device that converts AC current into DC current, and converts the AC current generated by the generator 5 into DC current and supplies it to the high-voltage battery 2.

[0044] DC / DC converter 8 is a device that steps down input power and outputs it, and steps down the output voltage of high-voltage battery 2 and supplies it to low-voltage battery 3. DC / DC converter 8 is provided with a main voltage sensor SN1 that can detect the voltage of electricity input to DC / DC converter 8 via high-voltage line 31, i.e., the voltage of high-voltage circuit 30. Main voltage sensor SN1 corresponds to the "second detection device" in the claims.

[0045] The PTC heater 9 and the electric compressor 10 constitute a heating and cooling device 11 of the vehicle 1. Specifically, the PTC heater 9 is a device for heating the interior of the vehicle 1, and the electric compressor 10 is a device for cooling the interior of the vehicle 1. In this embodiment, a cooling plate (not shown) is provided for cooling the high-voltage battery 2, and the electric compressor 10 also cools this cooling plate.

[0046] (OBC circuit) The OBC circuit 40 includes an OBC (On Board Charger) 41 and an AC charging inlet 42. The OBC circuit 40 also includes a P-side OBC line 43a, which is a positive-side line connected to the P-side high-voltage line 31a, and an N-side OBC line 43b, which is a negative-side line connected to the N-side high-voltage line 31b.

[0047] The OBC 41 is a device for supplying power from an external power source 300 to the high-voltage battery 2 to charge the high-voltage battery 2. In this embodiment, the OBC 41 receives power from the external AC power source 300 to charge the high-voltage battery 2. Accordingly, the OBC 41 has an AC / DC converter 43, which is a device for converting AC current to DC current. The AC charging inlet 42 is a device for electrically connecting the OBC 41 to a cable connected to the external AC power source 300. The AC charging inlet 42 is electrically connected to the OBC 41 and is configured to receive and mate with a connector (hereinafter, appropriately referred to as an AC charging connector) provided at the end of the cable. The OBC 41 is provided with an OBC voltage sensor SN2 capable of detecting the voltage of the OBC circuit 40. The OBC 41 corresponds to the "external charging device" in the claims, and the OBC voltage sensor SN2 corresponds to the "detection device" in the claims. In this embodiment, the main voltage sensor SN1 and the OBC voltage sensor SN2 function as a "third detection device" in the claims.

[0048] In this embodiment, the high-voltage battery 2 can also be charged with power from a DC power source outside the vehicle. Specifically, the vehicle 1 is provided with a DC charging inlet 50 that is connected to the high-voltage circuit 30 via contactors 51 and 52 and that fits into a connector of a cable connected to the DC power source outside the vehicle to electrically connect the DC power source outside the vehicle and the high-voltage circuit 30.

[0049] (controller) 2 is a block diagram showing the relationship between controllers mounted on the vehicle 1. The vehicle 1 includes the following controllers: a C-BCM (Center-Body Control Module) 200, a PCM (Power Control Module) 201, an ECM (Engine Control Module) 202, a DMCM (Driver Moor Control Module) 203, an SGCM (Starter Generator Control Module) 204, a BCCM (Battery Charger Control Module) 205, a BECM (Battery Energy Control Module) 206, an ESU (Electric Power Supply Unit) 207, a BCCM (Battery Charger Control Module) 208, a BECM (Battery Energy Control Module) 209, an ESU (Electric Power Supply Unit) 210, a BCCM (Battery Charger Control Module) 211, a BECM (Battery Energy Control Module) 212, an ESU (Electric Power Supply Unit) 213, a BCCM (Battery Charger Control Module) 214, a BECM (Battery Energy Control Module) 215, an ESU (Electric Power Supply Unit) 216, a BCCM (Battery Charger Control Module) 217, a BECM (Battery Energy Control Module) 218, an ESU (Electric Power Supply Unit) 219, a BCCM (Battery Charger Control Module) 220, a BECM (Battery Energy Control Module) 221, a BECM (Battery Energy Control Module) 222, a DMCM (Driver Moor Control Module) 223, a DMCM (Driver Moor Control Module) 224, a SGCM (Starter Generator Control Module) 225, a BCCM (Battery Charger Control Module) 226, a BECM (Battery Energy Control Module) 227, a BECM (Battery Energy Control These controllers 200 to 207 are connected to the low-voltage battery 3 and operate by receiving power from the low-voltage battery 3.

[0050] Each controller 200-207 mainly performs the following controls: The C-BCM 200 controls doors, windows, etc. The PCM 201 controls the drivetrain devices of the vehicle 1. The ECM 202 controls the engine 22. The DMCM 203 controls the inverter 6. The SGCM 204 controls the converter 7. The BCCM 205 controls the OBC 41. The BECM 206 controls the high-voltage battery 2. The ESU 207 controls the air-conditioning device 11. These controllers 200-207 exchange signals with each other. For example, these controllers 200-206 communicate with each other via CAN (Controller Area Network).

[0051] 2 is a device that displays various types of information, and includes a display, etc. HMI is an abbreviation for Human Machine Interface.

[0052] (contactor) The vehicle 1 is provided with a pair of main contactors 71, 72 (P-side main contactor 71, N-side main contactor 72), a pre-charge contactor 73, and a pair of OBC contactors 81, 82 (P-side OBC contactor 81, N-side OBC contactor 82) as contactors. The contactors are electromagnetic switches including electromagnets, and connect or disconnect the electrical connection between two contacts in response to supplied power. When the contactors are closed, the two contacts are electrically connected and energized, and when the contactors are opened, the two contacts are electrically disconnected.

[0053] (Main contactor) The P-side main contactor 71 electrically connects and disconnects the positive terminal 2a of the high-voltage battery 2 and the high-voltage circuit 30. Specifically, the two contacts of the P-side main contactor 71 are connected to the positive terminal 2a of the high-voltage battery 2 (more specifically, the positive battery line 2d connected to the positive terminal 2a) and the P-side high-voltage line 31a, respectively, and the P-side main contactor 71 electrically connects and disconnects the positive terminal 2a of the high-voltage battery 2 and the P-side high-voltage line 31a.

[0054] The N-side main contactor 72 connects and disconnects the negative terminal 2b of the high-voltage battery 2 and the high-voltage circuit 30. Specifically, the two contacts of the N-side main contactor 72 are connected to the negative terminal 2b of the high-voltage battery 2 (more specifically, the negative battery line 2e connected to the negative terminal 2b) and the N-side high-voltage line 31b, respectively, and the N-side main contactor 72 connects and disconnects the electrical connection between the negative terminal 2b of the high-voltage battery 2 and the N-side high-voltage line 31b.

[0055] The pre-charge contactor 73 is disposed in parallel with one of the main contactors and connects and disconnects one terminal of the high-voltage battery 2 and the high-voltage circuit 30. Specifically, the two contacts of the pre-charge contactor 73 are connected to one terminal of the high-voltage battery 2 and the corresponding high-voltage line 31, and these are connected and disconnected by not only the main contactor but also the pre-charge contactor. However, the electrical resistance between one terminal of the high-voltage battery 2 and the high-voltage line 31 via the pre-charge contactor 73 is set to be larger than the electrical resistance between one terminal of the high-voltage battery 2 and the high-voltage line 31 via the main contactor disposed in parallel with the pre-charge contactor 73. Therefore, when both the pre-charge contactor 73 and the main contactor disposed in parallel with it are closed, electricity flows through the line on the main contactor side, which has lower electrical resistance, rather than through the line on the pre-charge contactor 73 side.

[0056] In this embodiment, the pre-charge contactor 73 is provided between the negative terminal 2b of the high-voltage battery 2 and the N-side high-voltage line 31b to make or break the electrical connection therebetween. In addition, an electrical resistor 74 is provided between the pre-charge contactor 73 and the N-side high-voltage line 31b. Hereinafter, the pre-charge contactor 73 will be referred to as the pre-contactor 73 where appropriate.

[0057] In this embodiment, since the pre-contactor 73 is provided to connect and disconnect the negative electrode terminal 2b and the N-side high voltage line 31b, the N-side main contactor 72 arranged in parallel with the pre-contactor 73 corresponds to the "first main contactor" in the claims, and the P-side main contactor 71 corresponds to the "second main contactor" in the claims.

[0058] (OBC contactor) The P-side OBC contactor 81 and the N-side OBC contactor 82 electrically connect and disconnect the high voltage circuit 30 and the OBC circuit 40 .

[0059] Specifically, the two contacts of the P-side OBC contactor 81 are connected to the P-side OBC line 43a and the P-side high-voltage line 31a, respectively, and the P-side OBC contactor 81 electrically disconnects the P-side OBC line 43a and the P-side high-voltage line 31a. The two contacts of the N-side OBC contactor 82 are connected to the N-side OBC line 43b and the N-side high-voltage line 31b, respectively, and the N-side OBC contactor 82 electrically disconnects the N-side OBC line 43b and the N-side high-voltage line 31b.

[0060] The P-side OBC contactor 81 and the N-side OBC contactor 82 correspond to the "external charging contactor" in the claims.

[0061] (Contactor control configuration) Fig. 3 is a block diagram showing the control configuration for the contactors. Each contactor is mainly controlled by a PCM 201. Specifically, the PCM 201 is supplied with power from the low-voltage battery 3. The PCM 201 opens and closes each contactor by switching between supplying and stopping power from the low-voltage battery 3 to each contactor. The PCM 201 corresponds to the "control device" in the claims.

[0062] Information detected by various sensors and operation signals from various switches are input to the PCM 201. Specifically, detection signals from the main voltage sensor SN1 and the OBC voltage sensor SN2 are input to the PCM 201. Hereinafter, the voltage of the high voltage circuit 30 detected by the main voltage sensor SN1 will be referred to as the main voltage, and the voltage of the OBC circuit 40 detected by the OBC voltage sensor SN2 will be referred to as the OBC voltage, where appropriate.

[0063] Furthermore, a signal is input to PCM 201 from AC charging inlet 42. Specifically, the signal is input to PCM 201 from AC charging inlet 42 via BCCM 205. AC charging inlet 42 is configured to output a predetermined signal (hereinafter referred to as an AC connector mating signal, as appropriate) to BCCM 205 when an AC connector is mated and external charging from external AC power source 300 is possible. When this AC connector mating signal is input from AC charging inlet 42, BCCM 205 transmits the signal to PCM 201.

[0064] When the PCM 201 receives the AC connector mating signal, it determines that an external charging request, which is a request to start external charging (a request to start external charging), has been issued. When it determines that the external charging request has been issued, the PCM 201 performs external charging preparation control to change the states of the contactors so that the main contactors 71, 72 and the OBC contactors 81, 82 are closed and the pre-contactor 73 is open until external charging starts (until power supply from the external AC power source 300 to the OBC circuit 40 and the OBC 41 starts to supply power). In this embodiment, when the states of the contactors are changed as a result of the execution of the external charging preparation control, the PCM 201 transmits a predetermined signal (hereinafter referred to as a power signal as appropriate) to the external AC power source 300, and upon receiving this power signal, the AC power source 300 starts supplying power to the OBC circuit 40.

[0065] When the external charging preparation control is performed, the OBC circuit 40, the high-voltage circuit 30, and the high-voltage battery 2 are electrically connected. These are also connected in a state where electrical resistance is small. As a result, when power supply from the AC power source 300 outside the vehicle starts thereafter, power is efficiently supplied to the high-voltage battery 2.

[0066] Here, external charging is performed while the vehicle is stopped. Then, when the vehicle 1 stops (i.e., after the vehicle has stopped), the PCM 201 closes each of the contactors 71, 72, 73, 81, and 82. As a result, when a request for external charging is issued, each of the contactors 71, 72, 73, 81, and 82 is in the closed state, and external charging preparation control is started in this state.

[0067] Furthermore, the PCM 201 determines that an external charging stop request, which is a request to stop external charging, has been issued when the AC connector mating signal is no longer input as a result of the AC connector being removed from the AC charging inlet 42. In addition, the PCM 201 also determines that an external charging stop request has been issued when the high-voltage battery 2 is fully charged or when a preset external charging time has elapsed.

[0068] Furthermore, when a request to stop external charging is issued, the PCM 201 opens each of the contactors 71, 72, 73, 81, and 82. External charging (output of power from the external power supply device 300 to the vehicle side) ends when the AC connector is removed from the AC charging inlet 42 or when the external power supply device 300 receives a predetermined signal from the PCM 201. For example, when the high-voltage battery 2 is fully charged or when a preset external charging time has elapsed, the PCM 201 transmits the above signal to the power supply device 300. As a result, external charging ends almost simultaneously with the PCM 201 determining that a request to stop external charging has been issued.

[0069] (Contactor failure determination) Next, we will explain the failure determination of each of the contactors 71, 72, 73, 81, and 82 performed by the PCM 201. The PCM 201 performs a failure determination of the contactors while external charging preparation control is being performed, that is, when an external charging request is issued (hereinafter, appropriately referred to as when external charging is requested), and when external charging is completed.

[0070] 4 to 6 are flowcharts showing the procedure for determining whether a contactor has a fault when external charging is requested. FIG. 7 is a flowchart showing the procedure for determining whether a contactor has a fault after external charging has ended. FIGS. 8 and 9 are diagrams showing the changes over time of each parameter when external charging is requested. FIG. 10 is a diagram showing the changes over time of each parameter when external charging has ended. Hereinafter, when the contactor is in a closed state, it will be referred to as ON, and when it is in an open state, it will be referred to as OFF. When the contactor has a fault in the closed state, it will be referred to as stuck ON, and when it has a fault in the open state, it will be referred to as stuck OFF.

[0071] 8(a) shows, from top to bottom, an external charging request flag, commands from the PCM 201 to each of the contactors, namely, the P-side main contactor 71, the N-side main contactor 72, the pre-contactor 73, the P-side OBC contactor 81, and the N-side OBC contactor 82, the main voltage, and the OBC voltage. The external charging request flag switches from 0 to 1 when an external charging request is issued, and switches from 1 to 0 when an external charging stop request is issued.

[0072] The graph of main voltage in Fig. 8(a) is a graph when there is no contactor failure. The graph (solid line) in Fig. 8(b) is a graph of main voltage when step S6 of failure determination, which will be described later, is performed and it is determined that the P-side main contactor 71 is stuck ON. The graph (solid line) in Fig. 8(c) is a graph of main voltage when step S14 of failure determination, which will be described later, is performed and it is determined that at least one of the P-side main contactor 71 and the pre-contactor 73 is stuck OFF. The graph (solid line) in Fig. 8(d) is a graph of main voltage when step S26 of failure determination, which will be described later, is performed and it is determined that the N-side main contactor 72 is stuck OFF. In Figs. 8(b) and 8(c), part of the main voltage in Fig. 8(a) is also shown by a dotted line.

[0073] Figure 9(a) is the same as Figure 8(a). On the other hand, the graph (solid line) in Figure 9(b) is a graph of the OBC voltage when step S16 of the fault determination described below is performed and it is determined that at least one of the OBC contactors 81, 82 is stuck OFF. Figure 9(b) also shows the OBC voltage in Figure 9(a) with a dotted line.

[0074] 10 shows the external charging execution flag, commands from the PCM 201 to each of the contactors, namely the P-side main contactor 71, the N-side main contactor 72, the pre-contactor 73, the P-side OBC contactor 81, and the N-side OBC contactor 82, and the main voltage. The external charging execution flag is a flag that changes from 0 to 1 when external charging starts and changes from 1 to 0 when external charging ends. In the main voltage graph in FIG. 10, the solid line represents the graph when no contactor failure occurs, and the dotted line represents the graph when step 34, described later, is performed and it is determined that at least one of the N-side main contactor 72 and the pre-contactor 73 is stuck ON.

[0075] (Fault detection process when external charging is requested) The flowchart in FIG. 4 starts when the vehicle is stopped and the PCM 201 has issued an OFF command to each contactor.

[0076] First, the PCM 201 determines whether an external charging request has been issued (whether an AC connector fitting signal has been input) (step S1). In the examples of Figures 8 and 9, the external charging request is issued at time t1, and the external charging flag is switched from 0 to 1.

[0077] When the determination in step S1 is YES (when the PCM 201 determines that an external charging request has been issued), the PCM 201 starts external charging preparation control. Specifically, first, the PCM 201 switches the commands to both of the OBC contactors 81 and 82 from OFF to ON (step S2). In the example of FIGS. 8 and 9, the commands to each of the OBC contactors 81 and 82 are switched ON at time t2.

[0078] Next, the PCM 201 waits for a predetermined first time period to elapse after performing step S2 (waits for the determination in step S3 to become YES), and then switches the command to the precontactor 73 from OFF to ON (step S4). In the examples of Figures 8 and 9, the command to the precontactor 73 is switched ON at time t3.

[0079] When step S4 is performed, the command issued from the PCM 201 to the P-side main contactor 71 is OFF. Therefore, if the P-side main contactor 71 is normal, the high-voltage battery 2 and the high-voltage circuit 30 will remain electrically disconnected even if the pre-contactor 73 is turned ON in step S4. Therefore, in this case, as shown in FIG. 8(a), the main voltage will remain near 0 even after time t3 (after step S5 is performed). In contrast, if the P-side main contactor 71 is stuck ON, turning the pre-contactor 73 ON in step S4 will start to electrically connect the high-voltage battery 2 and the high-voltage circuit 30. Therefore, in this case, as shown in FIG. 8(b), the main voltage will rise (increase) after time t3 (after step S4 is performed).

[0080] After step S4 is performed, the PCM 201 determines whether the main voltage has risen (increased) (step S5). If the determination is YES and the main voltage has risen, the PCM 201 determines that the P-side main contactor 71 is stuck ON (step S6). The PCM 201 also notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality notification or the like, and then ends the malfunction determination. Note that when the process proceeds to step S6, the external charging preparation control is also stopped.

[0081] On the other hand, if the determination in step S5 is NO and the main voltage has not risen (increased), the PCM 201 proceeds to step S11 in FIG. 5. In step S11, the PCM 201 determines whether a predetermined second time has elapsed since performing step S4. Then, the PCM 201 waits until this determination becomes YES (waits for the second time to elapse since performing step S4), and then performs step S12. In step S12, the PCM 201 switches the command to the P-side main contactor 71 from OFF to ON. In the examples of FIGS. 8 and 9, the command to the P-side main contactor 71 is switched to ON at time t4.

[0082] If neither the pre-contactor 73 nor the P-side main contactor 71 is stuck in the OFF position, step S12 turns both the pre-contactor 73 and the P-side main contactor 71 ON, thereby starting an electrical connection between the high-voltage circuit 30 and the high-voltage battery 2. Therefore, in this case, as shown in FIG. 8(a), the main voltage rises after time t4 (after step S12 is performed). In contrast, if at least one of the pre-contactor 73 and the P-side main contactor 71 is stuck in the OFF position, the high-voltage circuit 30 and the high-voltage battery 2 remain electrically disconnected, even when step S12 is performed. Therefore, in this case, as shown in FIG. 8(c), the main voltage does not change before and after time t4 (before and after step S12 is performed) and is maintained near 0.

[0083] After step S12 is performed, the PCM 201 determines whether or not there has been an increase (increase) in the main voltage (step S13). If the determination is YES and there has been no increase in the main voltage, the PCM 201 determines that at least one of the pre-contactor 73 and the P-side main contactor 71 is stuck OFF (step S14). The PCM 201 also notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality notification or the like, and then ends the malfunction determination. Note that when the process proceeds to step S14, the external charging preparation control is also stopped.

[0084] Furthermore, when step S12 is performed, the command issued from the PCM 201 to each OBC contactor 81, 82 is ON. Therefore, if these OBC contactors 81, 82 are normal, the high-voltage circuit 30 and the OBC circuit 40 are electrically connected. Thus, if the OBC contactors 81, 82 are normal, when the determination in step S13 is NO and the main voltage increases as a result of performing step S12, that is, when the high-voltage circuit 30 and the high-voltage battery 2 are electrically connected as a result of performing step S12, the high-voltage battery 2 and the OBC circuit 40 are electrically connected. Therefore, in this case, as shown in FIG. 9(a), after time t4 (after performing step S12), the OBC voltage rises (increases). In contrast, if one or both of the OBC contactors 81, 82 are stuck OFF, the high-voltage circuit 30 and the OBC circuit 40, and therefore the OBC circuit 40 and the high-voltage battery 2, are not electrically connected. Therefore, in this case, as shown in FIG. 9(b), the OBC voltage is maintained at around 0 even after time t4 (after step S12 is performed).

[0085] Thus, if the determination in step S13 is NO and the main voltage rises after step S12 is performed, that is, if the high-voltage circuit 30 and the high-voltage battery 2 are electrically connected as a result of step S12 being performed, the PCM 201 proceeds to step S15, where it determines whether or not the OBC voltage has risen (increased) after step S12 is performed. If the determination is YES and the OBC voltage has not risen (increased), the PCM 201 determines that at least one of the P-side OBC contactor 81 and the N-side OBC contactor 82 is stuck OFF (step S16). The PCM 201 also notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality or the like. Note that if the process proceeds to step S16, the external charging preparation control is also stopped.

[0086] If the determination in step S15 is NO and the OBC voltage increases after step S12 is performed, the PCM 201 proceeds to step S21 in FIG. 6. In step S21, the PCM 201 determines whether a predetermined third time has elapsed since step S12 was performed. Then, the PCM 201 waits until this determination becomes YES (waiting for the third time to elapse since step S12 was performed), and then switches the command to the N-side main contactor 72 from OFF to ON (step S22). In the example of FIGS. 8 and 9, the command to the N-side main contactor 72 is switched ON at time t5. Next, the PCM 201 waits until a predetermined fourth time has elapsed since step S22 was performed (waiting for the determination in step S23 to become YES), and then switches the command to the pre-contactor 73 from ON to OFF (step S24). In the example of FIGS. 8 and 9, the command to the pre-contactor 73 is switched OFF at time t6. Here, by performing step S24, the states of the contactors become such that the main contactors 71, 72 and the OBC contactors 81, 82 are ON (closed) and the pre-contactor 73 is OFF (open). As a result, the external charging preparation control ends by performing step S24.

[0087] At the time step S24 is performed, the commands issued from the PCM 201 to the P-side main contactor 71 and the N-side main contactor 72 are both ON. Therefore, if the N-side main contactor 72 is normal, electricity between the high-voltage battery 2 and the high-voltage circuit 30 flows through the N-side main contactor 72 rather than the pre-contactor 73 when step S24 is performed. Therefore, if the N-side main contactor 72 is normal, even if step S24 is performed and the command to the pre-contactor 73 is switched to OFF, the current path does not change, and as shown in FIG. 8(a), the main voltage does not drop (decrease) even after time t6 (after step S24 is performed). In contrast, if the N-side main contactor 72 is stuck OFF, electricity between the high-voltage battery 2 and the high-voltage circuit 30 flows through the pre-contactor 73 rather than the N-side main contactor 72 at the timing immediately before step S24 is performed. Therefore, in this case, the command to the pre-contactor 73 is switched OFF in step S24, electrically disconnecting the high-voltage battery 2 from the high-voltage circuit 30, and as shown in (d) of Figure 8, the main voltage drops (decreases) after time t6 (after step S24 is performed).

[0088] Thus, after performing step S24, the PCM 201 determines whether the main voltage has dropped (decreased) (step S25). If the determination is YES and the main voltage has dropped (decreased), the PCM 201 determines that the N-side main contactor 72 is stuck OFF (step S26). The PCM 201 also notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality notification or the like, and then ends the failure determination.

[0089] On the other hand, if the determination in step S25 is NO and the main voltage has not decreased after execution of step S24, the PCM 201 proceeds to step S27 and starts external charging. As described above, in this embodiment, the PCM 201 sends a power signal to the external power supply device 300, and in response to this, the external power supply device 300 starts supplying power to the OBC circuit 40 and ultimately to the high-voltage battery 2.

[0090] Here, there is a possibility that the OBC contactors 81 and 82 will be turned OFF after external charging has started. That is, the OBC contactors 81 and 82, which were not fixed OFF when step S15 was performed, may malfunction and be turned OFF after step S24 is performed. If at least one of the OBC contactors 81 and 82 is turned OFF after external charging has started, the OBC voltage will be lower than the main voltage. Specifically, the electrical connection between the high-voltage circuit 30 and the high-voltage battery 2 is maintained, so that the voltage of the high-voltage circuit 30 is maintained at a high voltage similar to that of the high-voltage battery 2. On the other hand, if at least one of the OBC contactors 81 and 82 is turned OFF, the electrical connection between the OBC circuit 40 and the high-voltage battery 2 is interrupted, so that the OBC voltage will be lower than the main voltage. However, as described above, the OBC circuit 40 is provided with the AC / DC converter 43 including a capacitor, and charge accumulates in the AC / DC converter 43 after external charging has started. Therefore, after external charging starts, even if at least one of the OBC contactors 81 and 82 is stuck in the OFF position, the voltage of the OBC circuit 40 is higher than 0.

[0091] Thus, after external charging is started, the PCM 201 determines whether the voltage difference between the main voltage and the OBC voltage (more specifically, the amount by which the OBC voltage is insufficient relative to the main voltage, i.e., the value obtained by subtracting the OBC voltage from the main voltage) is equal to or greater than a predetermined determination value (step S28). If the determination is YES and the voltage difference is equal to or greater than the determination value, that is, if the OBC voltage is lower than the main voltage by equal to or greater than the determination value, the PCM 201 determines that at least one of the OBC contactors 81, 82 is stuck OFF (step S29). Furthermore, the PCM 201 notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality notification or the like, and then ends the malfunction determination. On the other hand, if the determination is NO in step S28 and the voltage difference is less than the predetermined determination value, the PCM 201 ends the malfunction determination. The determination value is preset to a value greater than 0 and stored in the PCM 201.

[0092] In this embodiment, the first to fourth times are set as follows: The first time (time t2 to time t3) is set to be shorter than the second time (time t3 to time t4). The second time (time t3 to time t4) is set to be shorter than the third time (time t4 to time t5). The third time (time t4 to time t5) is set to be longer than the fourth time (time t5 to time t6). The fourth time (time t5 to time t6) is set to be longer than the first time (time t2 to time t3). Although the lengths of each time are not limited to those described above, setting the times as described above allows appropriate detection of voltage changes accompanying the opening and closing of each contactor, allowing for more appropriate determination of contactor failure, and shortening the time required for failure determination.

[0093] (Fault detection process when external charging ends) The flowchart in FIG. 7 is executed when external charging is being performed, the PCM 201 has issued an ON command to the main contactors 71 and 72 and the OBC contactors 81 and 82, and an OFF command to the pre-contactor 73.

[0094] First, the PCM 201 determines whether an external charging request has been issued, that is, whether external charging has ended (step S31). As described above, this determination is made based on the AC connector fitting signal, etc. In the example of FIG. 10, external charging ends at time t11.

[0095] When external charging ends and the determination in step S31 becomes YES, the PCM 201 switches the command to the N-side main contactor 72 from ON to OFF (step S32). In the example in Fig. 10, the command to the N-side main contactor 72 is switched to OFF at time t12. Note that when external charging ends, the supply of power from the external AC power supply 300 to the vehicle side (OBC circuit 40, high-voltage circuit 30, and high-voltage battery 2) stops thereafter.

[0096] Thus, the electrical connection between the OBC circuit 40, the high-voltage circuit 30, and the high-voltage battery 2 is maintained until immediately before step S32 is performed. Furthermore, at the time step S32 is performed, the P-side main contactor 71 remains ON. Therefore, if the N-side main contactor 72 is normally switched OFF or the pre-contactor 73 is normally OFF, the command to the N-side main contactor 72 is switched OFF, electrically disconnecting the high-voltage battery 2 and the high-voltage circuit 30. Accordingly, the electrical connection between the high-voltage battery 2 and the OBC circuit 40 is also disconnected. Therefore, in this case, as shown by the solid line in FIG. 10 , the main voltage drops (decreases) after time t12 when step S32 is performed. In contrast, if the N-side main contactor 72 or the pre-contactor 73 is stuck ON, the electrical connection between the high-voltage battery 2 and the high-voltage circuit 30 is maintained even if the command to the N-side main contactor 72 is switched OFF. Therefore, in this case, as shown by the chain line in FIG. 10, the main voltage does not decrease (drop) even after time t12 when step S32 is performed.

[0097] Thus, after step S32 is performed, the PCM 201 determines whether the main voltage has not dropped (decreased) (step S33). If the determination in step S33 is YES and the main voltage has not dropped (decreased) after step S32 is performed, the PCM 201 determines that at least one of the N-side main contactor 72 and the pre-contactor 73 is stuck ON (step S34). The PCM 201 also notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality notification or the like.

[0098] After step S34 is performed, or if the determination in step S33 is NO and the main voltage drops after step S32 is performed, the process proceeds to step S35, where the PCM 201 determines whether a predetermined fifth time has elapsed since step S32 was performed. Then, after the determination in step S35 becomes YES (after the fifth time has elapsed since step S32 was performed), the PCM 201 switches the commands to the P-side main contactor 71 and each OBC contactor 81, 82 from ON to OFF (step S36), and ends the fault determination process. Although not shown in the drawings, in this embodiment, the PCM 201 also performs a discharge process for the high-voltage circuit 30 after step S32.

[0099] Here, the above step S2 corresponds to the "first control" in the claims, the above step S4 corresponds to the "second control" in the claims, the above step S12 corresponds to the "third control" in the claims, the above step S22 corresponds to the "fourth control" in the claims, the above step S23 corresponds to the "fifth control" in the claims, and the above step S32 corresponds to the "sixth control" in the claims.

[0100] (action, etc.) As described above, in the above embodiment, when an external charging request is issued, the external charging preparation control is performed to set the states of the contactors so that the main contactors 71 and 72 and the OBC contactors 81 and 82 are ON and the pre-contactor 73 is OFF. This external charging preparation control is for electrically connecting the OBC circuit 40 and the high-voltage battery 2, and contactor failure determination is performed based on the timing of the external charging preparation control. Therefore, there is no need to separately open and close the contactors to determine contactor failure. This reduces power consumption for contactor opening and closing and prevents noise from being generated by contactor opening and closing at times unexpected by the user. Furthermore, in the above embodiment, when the external charging preparation control is performed, steps S2, S4, and S12 are sequentially performed to turn ON the OBC contactors 81 and 82, the pre-contactor 73, and the P-side main contactor 71 in this order. This prevents the generation of loud noises caused by multiple contactors being ON simultaneously. This reduces the discomfort felt by occupants when starting the vehicle 1. Furthermore, in the above embodiment, the two OBC contactors 81 and 82 are turned ON simultaneously while preventing these four contactors from being turned ON simultaneously. This reduces the time required to turn ON these OBC contactors 81 and 82 while keeping noise to a minimum. This reduces the time required for external charging preparation control and fault determination, shortening the time from when an external charging request is issued to when external charging starts after these controls and determinations, allowing external charging to start earlier.

[0101] Furthermore, steps S4 and S12 are performed before step S22 is performed, and the P-side main contactor 71 is turned ON while the pre-contactor 73 is ON and the N-side main contactor 72 is OFF. In other words, the positive terminal 2a of the high-voltage battery 2 is electrically connected to the high-voltage circuit 30 while the negative terminal 2b of the high-voltage battery 2 and the high-voltage circuit 30 are connected via the pre-contactor 73 in a state of high electrical resistance. Therefore, when the high-voltage battery 2 and the high-voltage circuit 30 are electrically connected, a high inrush current from the high-voltage battery 2 can be prevented from flowing to the high-voltage circuit 30, preventing failure of electrical devices provided in the high-voltage circuit 30. Furthermore, when the high-voltage circuit 30 and the OBC circuit 40 are electrically connected, the inrush current can be prevented from flowing to the OBC circuit 40, preventing failure of the OBC 41.

[0102] Furthermore, in the above embodiment, if at least one of the OBC contactors 81, 82 is stuck in OFF state, the OBC voltage does not increase after step S12 is performed (after the command to the P-side main contactor 71 is switched to ON), and this is utilized to perform the determination in step S15, and if the OBC voltage does not increase after step S12 is performed, it is determined that at least one of the OBC contactors 81, 82 is stuck in OFF state. Therefore, it is possible to appropriately determine whether or not the OBC contactors 81, 82 are stuck in OFF state, that is, whether or not they are faulty in the closed state.

[0103] In the above embodiment, if the P-side main contactor 71 is stuck ON, the main voltage rises after step S4 is performed (after the command to the pre-contactor 73 is switched to ON), and this is utilized to perform the determination in step S5, and if the main voltage rises after step S4 is performed, it is determined that the P-side main contactor 71 is stuck ON. Therefore, it is possible to appropriately determine whether the P-side main contactor 71 is stuck ON.

[0104] Furthermore, in the above embodiment, if at least one of the P-side main contactor 71 and the pre-contactor 73 is stuck in OFF state, the main voltage does not increase after step S12 is performed (after the command to the P-side main contactor 71 is switched to ON), and this is utilized to perform the determination in step S13, and if the main voltage does not increase after step S12 is performed, it is determined that at least one of the P-side main contactor 71 and the pre-contactor 73 is stuck in OFF state. Therefore, it is possible to appropriately determine whether or not there is a failure in the P-side main contactor 71 or the pre-contactor 73.

[0105] Furthermore, in the above embodiment, if the N-side main contactor 72 is stuck in OFF state, the main voltage drops after step S24 is performed (after the command to the pre-contactor 73 is switched to OFF), and this is utilized to perform the determination in step S25, and if the main voltage drops after step S24 is performed, it is determined that the N-side main contactor 72 is stuck in OFF state. Therefore, it is possible to appropriately determine whether or not the N-side main contactor 72 is stuck in OFF state.

[0106] In the above embodiment, if at least one of the OBC contactors 81, 82 is stuck in the OFF position, the OBC voltage becomes lower than the main voltage after external charging starts. This is utilized to perform the determination in step S28, and if the voltage difference between these voltages after external charging starts is equal to or greater than the determination value, it is determined that at least one of the OBC contactors 81, 82 is stuck in the OFF position. Therefore, a failure of the OBC contactors 81, 82 can be appropriately determined.

[0107] Furthermore, in the above embodiment, fault determination is performed using the timing at which the contactors 71, 72, 73, 81, and 82 are closed after external charging has ended, ensuring opportunities for these fault determinations. Furthermore, if at least one of the N-side main contactor 72 and the pre-contactor 83 is stuck ON, the determination in step S33 is performed using the fact that the main voltage does not decrease after step S32 is performed after external charging has ended (after the command to the N-side main contactor 72 is switched to OFF). If the main voltage does not decrease after step S32 is performed, it is determined that at least one of the N-side main contactor 72 and the pre-contactor 83 is stuck ON. Therefore, fault determination of the N-side main contactor 72 and the pre-contactor 83 can be performed appropriately.

[0108] (Variation) In the above embodiment, the main voltage sensor SN1 for detecting the voltage of the high-voltage circuit 30 is provided in the DC / DC converter 8, but the location of the main voltage sensor SN1 is not limited to this. Furthermore, the sensor for detecting an increase or decrease in the voltage of the high-voltage circuit 30 is not limited to this. For example, a current sensor or the like may be used to detect an increase or decrease in the voltage of the high-voltage circuit 30. Similarly, a current sensor or the like may be used instead of the OBC voltage sensor SN2 to detect an increase or decrease in the voltage of the OBC circuit 40.

[0109] In the above embodiment, the case where the pre-contactor 73 is arranged in parallel with the P-side main contactor 71 has been described, but the pre-contactor 73 may also be arranged in parallel with the N-side main contactor 72. When the pre-contactor 73 is arranged in parallel with the N-side main contactor 72, the "P-side main contactor" and the "N-side main contactor" may be interchanged in the above failure determination (flowcharts in FIGS. 4 to 7). The external charging device may also be one that charges the high-voltage battery with power from a DC power source outside the vehicle. [Explanation of symbols]

[0110] 2 High voltage battery (battery) 2a Positive terminal 2b Negative terminal 3 Low voltage battery 4 motors 6 inverters 30 High voltage circuit (1st circuit) 40 OBC circuit (2nd circuit) 41 OBC (external charging device) 43 AC / DC converter 71 P-side main contactor (second main contactor, main contactor) 72 N-side main contactor (first main contactor, main contactor) 73 Pre-contactor (pre-charge contactor) 81 P-side OBC contactor (external charging contactor) 82 N-side OBC contactor (external charging contactor) 201 PCM (controller) SN1 Main voltage sensor (detector, third detector) SN2 OBC voltage sensor (second detector, third detector)

Claims

1. A contactor failure determination device mounted on a vehicle includes a battery having a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects and disconnects an electrical connection between one of the positive terminal and the negative terminal and the first circuit, a second main contactor that connects and disconnects an electrical connection between the other of the positive terminal and the negative terminal and the first circuit, and a pre-charge contactor that is arranged in parallel with the first main contactor and connects and disconnects an electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; The control device, when performing the external charging preparation control, performs a first control to close each of the external charging contactors, performs a second control to close the pre-charge contactors after performing the first control, and performs a third control to close the second main contactor after performing the second control, and when the detection device detects that the voltage of the second circuit does not increase after performing the third control, determines that at least one of the external charging contactors has failed in an open state; and a second detection device capable of detecting an increase or decrease in the voltage of the first circuit, wherein the second detection device determines that at least one of the precharge contactor and the second main contactor is in an open state and has a fault when the second detection device detects that the voltage of the first circuit does not increase after the third control is performed.

2. 2. The contactor failure determination device for a vehicle according to claim 1, The contactor failure determination device for a vehicle, wherein the control device simultaneously closes both of the external charging contactors when the first control is performed.

3. 3. The vehicle contactor failure determination device according to claim 1, a second detection device capable of detecting an increase or decrease in voltage of the first circuit; The control device determines that the second main contactor has failed in a closed state when the second detection device detects that the voltage of the first circuit has increased after the second control is performed.

4. The vehicle contactor failure determination device according to any one of claims 1 to 3, When the external charging preparation control is performed, the control device: performing a fourth control to close the first main contactor after the third control is performed; performing a fifth control for opening the precharge contactor after the fourth control is performed; a contactor failure determination device for a vehicle, characterized in that when a decrease in voltage of the first circuit is detected by a second detection device capable of detecting an increase or decrease in voltage of the first circuit after the fifth control is performed, the device determines that the first main contactor has failed in an open state.

5. 5. The contactor failure determination device for a vehicle according to claim 4, A contactor failure determination device for a vehicle, characterized in that the time from when the second control is performed to when the third control is performed is shorter than the time from when the third control is performed to when the fourth control is performed.

6. 6. The contactor failure determination device for a vehicle according to claim 4 or 5, A contactor failure determination device for a vehicle, characterized in that the time from when the third control is performed to when the fourth control is performed is longer than the time from when the fourth control is performed to when the fifth control is performed.

7. The vehicle contactor failure determination device according to any one of claims 4 to 6, A contactor failure determination device for a vehicle, characterized in that the time from when the fourth control is performed to when the fifth control is performed is longer than the time from when the first control is performed to when the second control is performed.

8. The vehicle contactor failure determination device according to any one of claims 1 to 7, a third detection device capable of detecting a voltage difference between the first circuit and the second circuit; the control device determines that at least one of the external charging contactors has failed in an open state when the third detection device detects that the voltage of the second circuit is lower than the voltage of the first circuit by a predetermined determination value or more after the external charging starts.

9. The vehicle contactor failure determination device according to any one of claims 1 to 8, the control device performs a sixth control to open the first main contactor when the external charging is completed, and when a second detection device capable of detecting an increase or decrease in the voltage of the first circuit detects that the voltage of the first circuit does not decrease after the sixth control is performed, the control device determines that at least one of the first main contactor and the pre-charge contactor is in a closed state and has a fault.

10. The vehicle contactor failure determination device according to any one of claims 1 to 9, The external charging device has an AC / DC converter that converts AC current into DC current, and converts AC power from an external power source into DC current and supplies it to the battery.

11. The vehicle contactor failure determination device according to any one of claims 1 to 10, A contactor failure determination device for a vehicle, characterized in that the time from when the first control is performed to when the second control is performed is shorter than the time from when the second control is performed to when the third control is performed.

12. A contactor failure determination device mounted on a vehicle having a battery with a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects or disconnects the electrical connection between one of the positive terminal and the negative terminal and the first circuit, a second main contactor that connects or disconnects the electrical connection between the other of the positive terminal and the negative terminal and the first circuit, and a pre-charge contactor arranged in parallel with the first main contactor that connects or disconnects the electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; the control device, when performing the external charging preparation control, performs a first control to simultaneously close both of the external charging contactors, performs a second control to close the pre-charge contactors after performing the first control, and performs a third control to close the second main contactor after performing the second control, and, when the detection device detects that the voltage of the second circuit does not increase after performing the third control, determines that at least one of the external charging contactors has failed in an open state.

13. A contactor failure determination device mounted on a vehicle having a battery with a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects or disconnects the electrical connection between one of the positive terminal and the negative terminal and the first circuit, a second main contactor that connects or disconnects the electrical connection between the other of the positive terminal and the negative terminal and the first circuit, and a pre-charge contactor arranged in parallel with the first main contactor that connects or disconnects the electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; The control device When the external charging preparation control is performed, a first control is performed to close each of the external charging contactors, a second control is performed to close the pre-charge contactors after the first control is performed, and a third control is performed to close the second main contactor after the second control is performed, and when the detection device detects that the voltage of the second circuit does not increase after the third control is performed, it is determined that at least one of the external charging contactors is in an open state and has a fault; and a fourth control for closing the first main contactor after the third control is performed, a fifth control for opening the pre-charge contactor after the fourth control is performed, and when a second detection device capable of detecting an increase or decrease in voltage of the first circuit detects a decrease in voltage of the first circuit after the fifth control is performed, the first main contactor is determined to have failed in an open state.

14. A contactor failure determination device mounted on a vehicle having a battery with a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects and disconnects the electrical connection between one of the positive and negative terminals and the first circuit, a second main contactor that connects and disconnects the electrical connection between the other of the positive and negative terminals and the first circuit, and a pre-charge contactor arranged in parallel with the first main contactor that connects and disconnects the electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a third detection device capable of detecting a voltage difference between the first circuit and the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; The control device When the external charging preparation control is performed, a first control is performed to close each of the external charging contactors, a second control is performed to close the pre-charge contactors after the first control is performed, and a third control is performed to close the second main contactor after the second control is performed, and when the detection device detects that the voltage of the second circuit does not increase after the third control is performed, it is determined that at least one of the external charging contactors is in an open state and has a fault; and a third detection device that detects, after the start of external charging, that the voltage of the second circuit is lower than the voltage of the first circuit by a predetermined determination value or more, determines that at least one of the external charging contactors has failed in an open state.

15. A contactor failure determination device mounted on a vehicle having a battery with a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects or disconnects the electrical connection between one of the positive terminal and the negative terminal and the first circuit, a second main contactor that connects or disconnects the electrical connection between the other of the positive terminal and the negative terminal and the first circuit, and a pre-charge contactor arranged in parallel with the first main contactor that connects or disconnects the electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; The control device When the external charging preparation control is performed, a first control is performed to close each of the external charging contactors, a second control is performed to close the pre-charge contactors after the first control is performed, and a third control is performed to close the second main contactor after the second control is performed, and when the detection device detects that the voltage of the second circuit does not increase after the third control is performed, it is determined that at least one of the external charging contactors is in an open state and has a fault; and a sixth control for opening the first main contactor when the external charging is terminated, and when a second detection device capable of detecting an increase or decrease in voltage of the first circuit detects that the voltage of the first circuit does not decrease after the sixth control is executed, the device determines that at least one of the first main contactor and the pre-charge contactor is in a closed state and has a fault.

16. A contactor failure determination device mounted on a vehicle having a battery with a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects or disconnects the electrical connection between one of the positive terminal and the negative terminal and the first circuit, a second main contactor that connects or disconnects the electrical connection between the other of the positive terminal and the negative terminal and the first circuit, and a pre-charge contactor arranged in parallel with the first main contactor that connects or disconnects the electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, the external charging device has an AC / DC converter that converts AC current into DC current, converts AC power from an external power source into DC current, and supplies the DC current to the battery; an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; the control device performs a first control to close each of the external charging contactors when the external charging preparation control is performed, performs a second control to close the pre-charge contactor after the first control is performed, and performs a third control to close the second main contactor after the second control is performed, and when the detection device detects that the voltage of the second circuit does not increase after the third control is performed, determines that at least one of the external charging contactors has failed in an open state.

17. A contactor failure determination device mounted on a vehicle having a battery with a positive terminal and a negative terminal, a first circuit including an inverter and a motor, a first main contactor that connects or disconnects the electrical connection between one of the positive terminal and the negative terminal and the first circuit, a second main contactor that connects or disconnects the electrical connection between the other of the positive terminal and the negative terminal and the first circuit, and a pre-charge contactor arranged in parallel with the first main contactor that connects or disconnects the electrical connection between the one terminal and the first circuit, a second circuit including an external charging device capable of supplying power from a power source outside the vehicle to the battery to charge the battery; a pair of external charging contactors that respectively establish and break electrical connections between the negative and positive sides of the first circuit and the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that, after the vehicle has stopped, opens the first main contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors, and, when a request is made to start external charging in which the battery is charged by a power source outside the vehicle, performs external charging preparation control to change the states of the contactors so that the main contactors and each of the external charging contactors are closed and the pre-charge contactor is open before power supply from the power source outside the vehicle to the external charging device is started, an electrical resistance between the terminal and the first circuit via the precharge contactor is greater than an electrical resistance between the terminal and the first circuit via the first main contactor; the control device, when performing the external charging preparation control, performs a first control to close each of the external charging contactors, performs a second control to close the pre-charge contactors after performing the first control, and performs a third control to close the second main contactor after performing the second control, and when the detection device detects that the voltage of the second circuit does not increase after performing the third control, determines that at least one of the external charging contactors has failed in an open state; A contactor failure determination device for a vehicle, characterized in that the time from when the first control is performed to when the second control is performed is shorter than the time from when the second control is performed to when the third control is performed.

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