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 includes a detection device capable of detecting increase and decrease in a voltage of a second circuit including an external charge device. When a vehicle start request is issued, first control of closing one 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 main contactor that is not parallel with the precharge contactor is performed after the execution of the second control, and, upon detection by the detection device that the voltage of the second circuit increases after the execution of the third control, it is determined that a failure occurs in a state where the other external charge contactor is closed.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 make and break the electrical connection between them.

[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] In response to the above problem, the inventors of the present application have developed a method for connecting an external charging device to a circuit connected to a battery via a contactor (external charging contactor), and closing the contactor that connects and disconnects the battery and the circuit when the vehicle is started, and at the same time closing the external charging contactor. We investigated determining a fault in the external charging contactor based on a change in the voltage on the external charging device side that occurs when the battery-side contactor and the external charging contactor are closed simultaneously. However, we found that closing the battery-side contactor and the external charging contactor simultaneously generates a relatively loud noise due to multiple contactors being closed at the same time. We also investigated a configuration 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 a contactor fault.

[0009] That is, 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 an electrical connection between the one terminal and the first circuit, the contactor failure determination device including a second circuit including an external charging device that can charge the battery by supplying power from a power source outside the vehicle to the battery, a pair of external charging contactors that connect and disconnect an electrical connection between positive lines and negative lines of the first circuit and 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 detects an increase or decrease in voltage of the second circuit. and a control device that controls the first contactor, the second main contactor, the pre-charge contactor, and each of the external charging contactors so that these contactors are open while the vehicle is stopped, 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 a vehicle start request that is a request to start the vehicle is issued, the control device performs a first control to close one of the external charging contactors, performs a second control to close the pre-charge contactor 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 an increase in voltage of the second circuit after performing the third control, determines that the other external charging contactor is faulty in a closed state. and, after the third control is performed, the first main contactor is closed and the pre-charge contactor and the one external charging contactor are opened. This is characterized by the above (Claim 1).

[0010] In this device, when a vehicle startup request is issued, the first, second, and third controls are executed, and one external charging contactor, the pre-charge contactor, and the second main contactor are closed in that order. This prevents multiple contactors from being closed simultaneously immediately after a vehicle startup request is issued, for example, immediately after an occupant performs an operation to start the vehicle, thereby preventing the relatively loud noise that would otherwise be generated when multiple contactors are closed simultaneously. This prevents the occupant from feeling uncomfortable when the vehicle is started.

[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 further to 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, the battery and the first circuit are electrically connected by the execution of the second control and the third control. Therefore, even if one external charging contactor is closed by the execution of the first control, the first circuit and the second circuit are electrically disconnected as long as the other external charging contactor is normally open. By doing so, the voltage of the second circuit does not increase. In contrast, if the other external charging contactor is in a closed state and has a fault, as the battery and the first circuit are electrically connected, the battery and the second circuit are electrically connected via the first circuit, and the voltage of the second circuit increases. Utilizing the above, this device determines that the other external charging contactor is in a closed state and has a fault if the voltage of the second circuit increases after the third control is performed. Therefore, a fault in the external charging contactor can be appropriately determined.

[0014] Furthermore, in this device, after the third control is performed, the control device closes the first main contactor and opens the pre-charge contactor and one of the external charging contactors. According to this device, after the third control is performed, the battery and the first circuit are connected via the main contactors with low electrical resistance. Furthermore, the electrical connection between the battery and the second circuit via the external charging contactor and the first circuit is interrupted. Therefore, after the third control is performed, high power can be supplied from the battery to the motor provided in the first circuit. Therefore, when the motor functions as a drive source for the vehicle, the vehicle can be driven appropriately.

[0015] In the above configuration, preferably, when the control device performs the first control in response to the issuance of the vehicle start request, the control device closes an external charging contactor different from the external charging contactor that was closed when the control device performed the first control in response to the previous vehicle start request (claim 2).

[0016] According to this configuration, it is possible to determine whether two external charging contactors have a fault when at least two vehicle startup requests are issued. Also, by performing a fault determination for only one external charging contactor when one vehicle startup request is issued, it is possible to shorten the time from when a vehicle startup request is issued until the vehicle starts traveling after a fault determination is made.

[0017] In the above configuration, preferably, a second detection device capable of detecting an increase or decrease in voltage of the first circuit is provided, and when the second detection device detects an increase in voltage of the first circuit after the second control is performed, the control device determines that the second main contactor has failed in a closed state (see claim 3 ).

[0018] 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.

[0019] In the above configuration, preferably, 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, 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 a fault (see claim 4 ).

[0020] If both the pre-charge contactor and the second main contactor are normal, the third control is performed to close both of them, electrically connecting the battery and the first circuit and increasing the voltage of the first circuit. 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 when the third control is performed, and the voltage of the first circuit does not increase. Taking advantage of this, this configuration determines that at least one of the pre-charge contactor and the second main contactor is faulty and in the open state if the voltage of the first circuit does not increase after the third control is performed. Therefore, a failure of these contactors can be appropriately determined.

[0021] In the above configuration, preferably, 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 precharge contactor after performing the fourth 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 has decreased after performing the fifth control, the control device determines that the first main contactor has failed in an open state (see claim 5 ).

[0022] 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.

[0023] 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 6 ).

[0024] 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 1). 7 ).

[0025] In the above configuration, the time from when the fourth control is performed to when the fifth control is performed is preferably longer than the time from when the first control is performed to when the second control is performed (see claim 1). 8 ).

[0026] By setting the time as described above, a contactor failure can be determined more appropriately.

[0027] In the above configuration, preferably, after the third control is performed, the control device performs a sixth control to open the external charging contactor that was closed when the first control was performed while the first circuit and the battery are electrically connected, and when it is determined that the other external charging contactor has a fault in the closed state, if the detection device detects that the voltage of the second circuit does not decrease after the sixth control is performed, the control device determines that each of the external charging contactors has a fault in the closed state (see claim 9 ).

[0028] Even if one external charging contactor is faulty and closed, if the other external charging contactor is normal, opening the other external charging contactor while the first circuit and battery are electrically connected will interrupt the electrical connection between the battery and the second circuit, causing a drop in the voltage of the second circuit. On the other hand, if the other external charging contactor is also faulty and closed, controlling the other external charging contactor to open while the first circuit and battery are electrically connected will maintain the electrical connection between the battery and the second circuit, and no drop in the voltage of the second circuit will occur. Taking advantage of this, in this configuration, the other external charging contactor is controlled to open, and at this time the voltage of the second circuit If the pressure does not increase or decrease and one of the external charging contactors has already been determined to have a fault in the closed state, it is determined that not only one external charging contactor but also the other external charging contactor has a fault in the closed state, thereby making it possible to appropriately determine whether both external charging contactors have a fault.

[0029] 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 the DC current to the battery (see claim 10 ).

[0030] 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 ).

[0031] By setting the time as described above, a contactor failure can be determined more appropriately. [Effects of the Invention]

[0032] 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]

[0033] [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 a request to start the vehicle 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] 4 is a flowchart showing a procedure for determining whether a contactor has failed when the vehicle is stopped. [Figure 8] These figures show the changes in parameters over time when a request to start the vehicle is made, 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] These figures show the time changes in parameters when a request to start the vehicle is issued, where (a) is a diagram showing the case when the contactors are normal, (b) is a diagram of the OBC voltage when the target OBC contactor is stuck ON, and (c) is a diagram of the OBC voltage when both OBC contactors are stuck ON. [Figure 10] FIG. 10 is a diagram showing changes over time in parameters when the vehicle is stopped. DETAILED DESCRIPTION OF THE INVENTION

[0034] (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.

[0035] 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.

[0036] (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.

[0037] (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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] (OBC circuit) The OBC circuit 40 includes an OBC (On Board Charger) 41 and an AC charging inlet 42. The OBC circuit 40 also has 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.

[0045] 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 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.

[0046] 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.

[0047] (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, an ESU (Electric Power Supply Unit) 217, an ESU (Electric Power Supply Unit) 218, an ESU (Electric Power Supply Unit) 219, an ESU (Electric Power Supply Unit) 220, an ESU (Electric Power Supply Unit) 221, an ESU (Electric Power Supply Unit) 222, an ESU (Electric Power Supply Unit) 223, an ESU (Electric Power Supply Unit) 224, an ESU (Electric Power Supply Unit) 225, an ESU (Electric Power Supply Unit) 226, an ESU (Electric Power Supply Unit) 227, an ESU (Electric Power Supply Unit) 228, an ESU (Electric These controllers 200 to 207 are connected to the low-voltage battery 3 and operate by receiving power from the low-voltage battery 3.

[0048] 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 200-207 communicate with each other via CAN (Controller Area Network).

[0049] 2 is a device that displays various types of information, and includes a display, etc. HMI is an abbreviation for Human Machine Interface.

[0050] (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 make and break the electrical connection between two contacts in response to supplied power. When the contactors are closed, the two contacts are electrically connected and enter a conducting state, and when the contactors are opened, the two contacts are electrically disconnected and enter a non-conducting state.

[0051] (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.

[0052] 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.

[0053] 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.

[0054] 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 and break the electrical connection therebetween. A resistor 74 is also 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.

[0055] 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.

[0056] (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 .

[0057] 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.

[0058] The P-side OBC contactor 81 and the N-side OBC contactor 82 correspond to the "external charging contactor" in the claims.

[0059] (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.

[0060] 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.

[0061] The vehicle 1 is provided with a start switch SW1 that allows the occupant to start and stop the vehicle 1, and an operation signal of this start switch SW1 is also input to the PCM 201. The start switch SW1 is OFF when the vehicle is stopped, and when it is switched ON, the PCM 201 determines that a start request for the vehicle 1 (vehicle start request) has been issued (a start request has been made to the vehicle 1). When it determines that a start request has been issued, the PCM 201 starts the vehicle 1. That is, the PCM 201 starts the supply of electricity to the controllers 200 to 207 to start them and make various devices operable. Thereafter, the PCM 201 starts driving the motor 4 in response to the driver's operation.

[0062] Furthermore, when the start switch SW1 is switched from OFF to ON, the PCM 201 opens and closes these contactors so that the states of the contactors after a predetermined time has elapsed (after the contactor failure determination described below does not determine that the contactors have failed and this failure determination has ended) are as follows: the main contactors 71, 72 are closed, and the pre-contactor 73 and the OBC contactors 81, 82 are open. Furthermore, when the start switch SW1 is switched from ON to OFF, the PCM 201 opens and closes these contactors so that the states of the main contactors 71, 72, the pre-contactor 73, and the OBC contactors 81, 82 are closed after a predetermined time has elapsed.

[0063] (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 failure determination is performed when a request to start the vehicle 1 is issued (when the start switch SW1 is switched from OFF to ON) and when the vehicle 1 is stopped (when the start switch SW1 is switched from ON to OFF).

[0064] When a request to start the vehicle 1 is issued, the PCM 201 performs a failure determination on one of the two OBC contactors 81, 82, the OBC contactor 81 (82). Then, when a request to start the vehicle 1 is next issued, the PCM 201 switches the OBC contactor to be subjected to the failure determination and performs a failure determination on the other OBC contactor 82 (81). In other words, the PCM 201 alternately performs a failure determination on the P-side OBC contactor 81 and a failure determination on the N-side OBC contactor 82 every time a request to start the vehicle 1 is issued.

[0065] Figures 4 to 6 are flowcharts showing the procedure for determining whether a contactor has a fault, which is performed when a request to start the vehicle 1 is issued. Figure 7 is a flowchart showing the procedure for determining whether a contactor has a fault, which is performed when the vehicle 1 is stopped. Figures 8 and 9 are diagrams showing the time changes of each parameter when a request to start the vehicle 1 is issued. Figure 10 is a diagram showing the time changes of each parameter when the vehicle 1 is stopped. 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. Furthermore, 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.

[0066] FIG. 8A shows, from top to bottom, the state of the start switch SW1, the P-side main contactor 71, the N-side main contactor 72, the pre-contactor 73, the OBC contactor 81 (82) that is the target of failure determination (target OBC contactor), and the OBC contactor 82 (81) that is not the target of failure determination (non-target OBC contactor), as well as the commands from the PCM 201, the main voltage, and the OBC voltage. The main voltage graph in FIG. 8A is a graph showing the case where the contactors are not faulty. The graph in FIG. 8B (solid line) is a graph showing the main voltage when step S7 (described later) is performed and it is determined that the P-side main contactor 71 is stuck ON. The graph in FIG. 8C (solid line) is a graph showing the main voltage when step S14 (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 Figure 8(d) is a graph of the main voltage when step S26, which will be described later, is performed and it is determined that the N-side main contactor 72 is stuck OFF. Figures 8(b) and 8(c) also show a part of the main voltage in Figure 8(a) with a dotted line.

[0067] 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 (described later) is performed and it is determined that the target OBC contactor 81 (82) is stuck ON. The graph (solid line) in Figure 9(c) is a graph of the main voltage when step S28 (described later) is performed and it is determined that both OBC contactors 81, 82 are stuck ON. In Figures 9(b) and 9(c), the OBC voltage in Figure 9(a) is also shown by a dotted line.

[0068] Figure 10 shows graphs of the same parameters as Figures 8(a) and 9(a). In the main voltage graph in Figure 10, the solid line is a graph when there is no contactor failure, the chain line is a 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, and the dashed line is a graph when step 38 described later is performed and it is determined that the P-side main contactor 71 is stuck ON.

[0069] (Fault detection process at startup) The flowchart in Figure 4 is executed when the start switch SW1 is OFF, the PCM 201 has issued an OFF command to each contactor, the high-voltage battery 2 and the high-voltage circuit 30 are electrically disconnected, and the main voltage is near 0.

[0070] First, the PCM 201 determines whether the start switch SW1 has been switched from OFF to ON and a request to start the vehicle 1 has been issued (step S1). This determination is made based on a signal from the start switch SW1. In the examples of FIGS. 8 and 9, the start switch SW1 is switched from OFF to ON at time t1.

[0071] When the determination in step S1 becomes YES (when the start switch SW1 is switched from OFF to ON), the PCM 201 determines one of the P-side OBC contactor 81 and the N-side OBC contactor 82 as the target OBC contactor (step S2). Specifically, the PCM 201 determines, as the target of a new failure determination, the OBC contactor 81 (82) that is different from the OBC contactor 82 (81) that was determined as the target of the failure determination in step S2, which was previously performed when the start switch SW1 was switched ON.

[0072] Next, the PCM 201 switches from OFF to ON the command to the non-target OBC contactor 82 (81), which is an OBC contactor 82 (81) different from the OBC contactor 81 (82) determined as the target OBC contactor in step S2. In the examples of Figures 8 and 9, the command to the non-target OBC contactor 82 (81) is switched ON at time t2.

[0073] Next, the PCM 201 waits for a predetermined first time period to elapse after performing step S3 (waits for the determination in step S4 to become YES), and then switches the command to the precontactor 73 from OFF to ON (step S5). In the examples of Figures 8 and 9, the command to the precontactor 73 is switched ON at time t3.

[0074] When step S5 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 S5. 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 S5 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 S5 is performed).

[0075] After step S5 is performed, the PCM 201 determines whether the main voltage has risen (increased) (step S6). 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 S7). The PCM 100 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.

[0076] On the other hand, if the determination in step S6 is NO and the main voltage has not 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 S5. Then, the PCM 201 waits until this determination becomes YES (waits for the second time to elapse since performing step S5), 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.

[0077] If neither the pre-contactor 73 nor the P-side main contactor 71 is stuck in the OFF position, step S12 is performed to turn 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, the main voltage rises (increases) after time t4 (after step S12 is performed) as shown in FIG. 8(a). In contrast, if at least one of the pre-contactor 73 and the P-side main contactor 71 is stuck OFF, the high-voltage circuit 30 and the high-voltage battery 2 remain electrically disconnected even when step S12 is performed. Therefore, in this case, the main voltage does not change and remains near 0 before and after time t4 (before and after step S12 is performed) as shown in FIG. 8(c).

[0078] After step S12 is performed, the PCM 201 determines whether or not there has been a rise (increase) in the main voltage (step S13). If the determination is YES and there has been no rise 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 100 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.

[0079] Furthermore, when step S12 is performed, the command issued from the PCM 201 to the non-target OBC contactor 82 (81) is ON, and the command issued to the target OBC contactor 81 (82) is OFF. Therefore, if the target OBC contactor 81 (82) is not stuck ON, the high-voltage circuit 30 and the OBC circuit 40 are maintained in an electrically disconnected state at the time step S12 is performed. Therefore, if the target OBC contactor 81 (82) is not stuck ON, the OBC voltage is maintained near 0 even if the high-voltage circuit 30 and the high-voltage battery 2 are electrically connected as a result of performing step S12. That is, in this case, as shown in FIG. 9(a), the OBC voltage does not change around time t4 (before and after performing step S12).

[0080] On the other hand, if the target OBC contactor 81 (82) is stuck ON, the high-voltage circuit 30 and the OBC circuit 40 are electrically connected at the time step S12 is performed. Therefore, in this case, when the high-voltage circuit 30 and the high-voltage battery 2 are electrically connected as step S12 is performed, the OBC voltage rises (increases). That is, in this case, as shown in FIG. 9(b), the OBC voltage rises after time t4 (after step S12 is performed).

[0081] Thus, if the determination in step S13 is NO and the main voltage rises (increases) after execution of step S12, that is, if the high-voltage circuit 30 and the high-voltage battery 2 are electrically connected as a result of execution of step S12, the PCM 201 proceeds to step S15. Then, in step S15, the PCM 201 determines whether the OBC voltage rises (increases) as a result of execution of step S12. Then, if the determination in step S15 is YES and the OBC voltage has risen, the PCM 201 determines that the target OBC contactor 81 (82) is stuck ON (step S16). Furthermore, the PCM 100 notifies the occupant of the abnormality by causing the HMI device 208 to display or the like informing the occupant of the abnormality.

[0082] If the determination in step S15 is NO, or after step S16, the PCM 201 proceeds to step S21 in FIG.

[0083] In step S21, the PCM 201 determines whether a predetermined third time has elapsed since step S12 was performed. The PCM 201 then waits until this determination becomes YES (waits until the third time has elapsed 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 (waits until the determination in step S23 becomes YES), and then switches the commands to both the pre-contactor 73 and the non-target OBC contactor 82 (81) from ON to OFF (step S24). In the example of FIGS. 8 and 9, the commands to the pre-contactor 73 and the non-target OBC contactor 82 (81) are switched OFF at time t6.

[0084] 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 the main voltage does not drop after time t6 (after step S24 is performed), as shown in FIG. 8(a). 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, when the command to the pre-contactor 73 is switched OFF in step S24, the high-voltage battery and the high-voltage circuit 30 are electrically disconnected, and as shown in (d) of Figure 8, the main voltage drops (decreases) after time t6 (after step S24 is performed).

[0085] 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). Furthermore, the PCM 100 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.

[0086] Furthermore, immediately before step S24 is performed, the command issued from the PCM 201 to the non-target OBC contactor 82 (81) is ON. Thus, if the target OBC contactor 81 (82) is stuck ON (i.e., if step S16 is performed in response to a YES determination in step S15), the OBC circuit 40 and the high-voltage circuit 30 are electrically connected immediately before step S24 is performed. Furthermore, if the N-side main contactor 72 is normal and there is no drop in the main voltage after step S24 is performed, the electrical connection between the high-voltage battery 2 and the high-voltage circuit 30 is maintained even after step S24 is performed. Therefore, if there is no drop in the main voltage after step S24 is performed and the target OBC contactor 81 (82) is stuck ON, the OBC circuit 40 and the high-voltage battery 2 are electrically connected via the high-voltage circuit 30 immediately before step S24 is performed.

[0087] Therefore, if there is no drop in the main voltage after step S24 is performed, and the target OBC contactor 81 (82) is stuck ON but the non-target OBC contactor 82 (81) is not stuck ON, as shown in Figure 9 (b), when step S24 is performed at time t6 and the command to the non-target OBC contactor 82 (81) is switched to OFF, the OBC circuit 40 and the high voltage circuit 30 are electrically disconnected, causing the OBC voltage to drop.

[0088] On the other hand, if there is no drop in the main voltage after step S24 is performed and both the target OBC contactor 81 (82) and the non-target OBC contactor 82 (81) are stuck ON, even if step S24 is performed and the command for the non-target OBC contactor 82 (81) is switched to OFF, the electrical connection between the OBC circuit 40 and the high voltage circuit 30 is maintained, and as a result, the OBC voltage does not drop (decrease) after time t6 (after step S24 is performed), as shown in Figure 9 (c).

[0089] If the determination in step S25 is NO and there is no drop in the main voltage after execution of step S24, the PCM 201 proceeds to step S27, where it determines whether the following conditions are met: it has been determined that the target OBC contactor 81 (82) is stuck ON (i.e., step S16 has been executed), and there is no drop (decrease) in the OBC voltage due to execution of step S24. If the determination in step S27 is YES and the above conditions are met, it determines that both the target OBC contactor 81 (82) and the non-target OBC contactor 82 (81) are stuck ON (step S28). Furthermore, the PCM 100 notifies the occupant of the abnormality by causing the HMI device 208 to display an abnormality notification, and then ends the malfunction determination. On the other hand, if the determination in step S27 is NO and the above condition is not satisfied, the PCM 201 determines that the target OBC contactor 81 (82) is normal (not stuck ON), and ends the failure determination.

[0090] 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 for appropriate detection of voltage changes accompanying the opening and closing of each contactor, more appropriate determination of contactor failure, and shortens the time required for failure determination.

[0091] (Fault detection process when the vehicle is stopped) The flowchart in FIG. 7 is executed when the start switch SW1 is ON, the PCM 201 issues an ON command to the N-side main contactor 72 and the P-side main contactor 71, and the PCM 201 issues an OFF command to the pre-contactor 73 and each OBC contactor 81, 82.

[0092] First, the PCM 201 determines whether the start switch SW1 has been switched from ON to OFF (step S31). This determination is made based on a signal from the start switch SW1. In the example of Fig. 10, the start switch SW1 is switched from ON to OFF at time t11.

[0093] When the start switch SW1 is switched from ON to OFF and the determination in step S1 becomes YES, the PCM 201 switches the command to the N-side main contactor 72 from ON to OFF (step S32). In the example of Fig. 10, the command to the N-side main contactor 72 is switched to OFF at time t12.

[0094] At the time step S32 is performed, the P-side main contactor 71 remains ON. Therefore, if the N-side main contactor 72 is switched OFF normally or the pre-contactor 73 is normally OFF, the N-side main contactor 72 is switched OFF, electrically disconnecting the high-voltage battery 2 and the high-voltage circuit 30. Therefore, as shown by the solid line in FIG. 10 , the main voltage drops 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. Therefore, in this case, as shown by the dashed line in FIG. 10 , the main voltage does not drop after time t12 when step S32 is performed.

[0095] After step S32 is performed, the PCM 201 determines whether the main voltage has not decreased (step S33). If the determination in step S33 is YES, that is, the main voltage has not decreased, the PCM 201 disconnects the N-side main contactor 72 and the pre-contactor 73. It is determined that at least one of the conductors 73 is stuck ON (step S34). On the other hand, if the determination in step S33 is NO and the main voltage has dropped, the PCM 201 proceeds to step S39.

[0096] After step S34, the PCM 201 waits until a predetermined fifth time has elapsed since step S32 was performed (waiting for the determination in step S35 to become YES), and then switches the command to the P-side main contactor 71 from ON to OFF (step S36). In the example of Fig. 10, the command to the P-side main contactor 71 is switched to OFF at time t13.

[0097] If it is determined in step S34 that at least one of the N-side main contactor 72 and the pre-contactor 73 is stuck ON, the high-voltage battery 2 and the high-voltage circuit 30 are electrically connected immediately before step S36 is performed. Therefore, unless the P-side main contactor 71 is stuck ON, the high-voltage battery 2 and the high-voltage circuit 30 are electrically disconnected when the command to the P-side main contactor 71 is switched OFF in step S36. As a result, as shown by the dashed line in FIG. 10 , the main voltage drops after time t13 (after step S36 is performed). On the other hand, if the P-side main contactor 71 is stuck ON, the electrical connection between the high-voltage battery 2 and the high-voltage circuit 30 is maintained even when the command to the P-side main contactor 71 is switched OFF in step S36. As a result, in this case, as shown by the chain line in FIG. 10 , the main voltage does not drop even after time t13 when step S36 is performed.

[0098] After performing step S36, the PCM 201 determines whether the main voltage has not dropped (step S37). If the determination in step S37 is YES, meaning the main voltage has not dropped, the PCM 201 determines that the P-side main contactor 71 is stuck ON (step S38). 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.

[0099] On the other hand, if the determination in step S37 is NO and the main voltage has dropped, the PCM 201 ends the process without determining that the P-side main contactor 71 is stuck ON.

[0100] Returning to step S33, if the determination in step S33 is NO and the main voltage has dropped as a result of performing step S32, the PCM 201 waits for a predetermined fifth time to elapse after performing step S32 (waits for the determination in step S39 to become YES), as in steps S35 and S36, and then switches the command to the P-side main contactor 71 from ON to OFF (step S40). In this case, the process ends immediately. Although not shown in the drawings, in this embodiment, the PCM 201 also performs a discharge process for the high-voltage circuit 30 after the above step S32.

[0101] Here, the above step S3 corresponds to the "first control" in the claims, the above step S5 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 step of switching the pre-contactor 73 OFF in the above step S24 corresponds to the "fifth control" in the claims, and the step of switching the non-target OBC contactor 82 (81) OFF in the above step S24 corresponds to the "sixth control."

[0102] (effect, etc.) As described above, in the above embodiment, when the PCM 201 determines that the start switch SW1 has been switched from OFF to ON and a request to start the vehicle 1 has been issued, the PCM 201 performs steps S3, S5, and S12 to turn ON the non-target OBC contactor 82 (81), the pre-contactor 73, and the P-side main contactor 71 in this order. This prevents these contactors from being turned ON simultaneously immediately after the start switch SW1 is turned ON, thereby preventing the generation of a loud noise that would occur if multiple contactors were turned ON simultaneously. This prevents the occupants from feeling uncomfortable when the vehicle 1 is started.

[0103] Furthermore, with the pre-contactor 73 ON and the N-side main contactor 72 OFF, the P-side main contactor 71 is turned ON. That is, with the negative terminal 2b of the high-voltage battery 2 and the high-voltage circuit 30 connected via the pre-contactor 73 in a state of high electrical resistance, the positive terminal 2a of the high-voltage battery 2 and the high-voltage circuit 30 are electrically connected. 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 into the high-voltage circuit 30, preventing breakdowns in 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 also be prevented from flowing into the OBC circuit 40, preventing breakdowns in the OBC 41.

[0104] In the above embodiment, if the target OBC contactor 81 (82) is stuck ON, the OBC voltage rises after step S12 is performed (after the P-side main contactor 71 is switched ON). This is utilized to perform the determination in step S15, and if the OBC voltage rises after step S12 is performed (if the determination in step S15 is YES), it is determined that the target OBC contactor 81 (82) is stuck ON. Therefore, it is possible to appropriately determine whether the target OBC contactor 81 (82) is stuck ON, that is, whether it has failed in the closed state.

[0105] Furthermore, in the above embodiment, the PCM 201 alternately performs a failure determination for the P-side OBC contactor 81 and a failure determination for the N-side OBC contactor 82 each time a startup request for the vehicle 1 is issued. Therefore, it is possible to determine a failure in the two OBC contactors 81, 82 when at least two startup requests are issued. Furthermore, by limiting the number of OBC contactors 81, 82 for which a failure determination is performed when a single startup request is issued to one, it is possible to shorten the time required for the failure determination compared to when a failure determination is performed separately for the two OBC contactors 81, 82. Therefore, it is possible to start driving the vehicle 1 sooner after a startup request is issued.

[0106] Furthermore, in the above embodiment, after step S12, step S22 is performed to switch the N-side main contactor 72 ON, and then step S24 is performed to switch the pre-contactor 73 and the non-target OBC contactor 82 (81) OFF. In other words, after step S12, the high-voltage battery 2 and the high-voltage circuit 30 are connected in a state where electrical resistance is low, and the electrical connection between the high-voltage battery 2 and the OBC circuit 40 via the high-voltage circuit 30 is cut off. Therefore, high power can be supplied to the motor 4 provided in the high-voltage circuit 30 immediately after step S24 is performed. This allows the vehicle 1 to start running appropriately early.

[0107] In the above embodiment, if the N-side main contactor 72 is stuck in the OFF position, the determination in step S25 is made by utilizing the fact that the main voltage drops after step S24 is performed (after the pre-contactor 73 is switched to OFF), and if the main voltage drops after step S24 is performed (if the determination in step S25 is YES), it is determined that the N-side main contactor 72 is stuck in the OFF position. Therefore, it is possible to appropriately determine whether the N-side main contactor 72 is stuck in the OFF position.

[0108] In the above embodiment, if the P-side main contactor 71 is stuck ON, the main voltage rises after step S5 is performed (after the pre-contactor 73 is switched ON), and this is utilized to perform the determination in step S6. If the main voltage rises after step S5 is performed (if the determination in step S6 is YES), the P-side main contactor 71 is stuck ON. Therefore, it can be appropriately determined whether or not the P-side main contactor 71 is stuck ON.

[0109] Furthermore, in the above embodiment, if at least one of the P-side main contactor 71 and the pre-contactor 73 is stuck OFF, the main voltage does not increase after step S12 is performed (after the P-side main contactor 71 is switched ON), and this is used to perform the determination in step S13. If the main voltage does not increase after step S12 is performed (if the determination in step S13 is YES), it is determined that at least one of the P-side main contactor 71 and the pre-contactor 73 is stuck OFF. Therefore, it is possible to appropriately determine whether or not the P-side main contactor 71 and the pre-contactor 73 are faulty.

[0110] Furthermore, in the above embodiment, if both OBC contactors 81, 82 are stuck ON, the OBC voltage does not decrease after step S24 is performed (after the non-target OBC contactor 82 (81) is switched OFF), and by utilizing this, the determination of step S27 is performed, and if the OBC voltage does not decrease after step S24 is performed (if the determination of step S27 is YES), it is determined that both OBC contactors 81, 82 are stuck ON. Therefore, it is possible to appropriately determine whether these OBC contactors 81, 82 are faulty.

[0111] (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.

[0112] In the above embodiment, the case where the pre-contactor 73 is arranged in parallel with the N-side main contactor 72 has been described, but the pre-contactor 73 may also be arranged in parallel with the P-side main contactor 71. When the pre-contactor 73 is arranged in parallel with the P-side main contactor 71, the "P-side main contactor" and the "N-side main contactor" may be interchanged in the above fault determination (the flowcharts in FIGS. 4 to 7).

[0113] In the above embodiment, when the command to the non-target OBC contactor 82 (81) is switched from OFF to ON (step S3) and the command to the pre-contactor 73 is switched from OFF to ON (step S5), only a determination as to whether or not the P-side main contactor 71 is stuck ON (steps S6, S7) is performed. However, in addition to this determination, a determination as to whether or not the OBC voltage has increased may be made, and if the OBC voltage has increased, it may be determined that the target OBC contactor 81 (82) is stuck ON. Also, the external charging device may charge the high-voltage battery using power from a DC power source outside the vehicle. [Explanation of symbols]

[0114] 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) SN2 OBC voltage sensor (second detection device)

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 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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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 a vehicle start request that is a request to start the vehicle is issued, performs a first control to close one of the external charging contactors, performs a second control to close the pre-charge contactor after performing the first control, and performs a third control to close the second main contactor after performing the second control; when the detection device detects an increase in voltage of the second circuit after performing the third control, determines that the other external charging contactor has failed in a closed state, and after performing the third control, closes the first main contactor and opens the pre-charge contactor and one of the external charging contactors.

2. 2. The contactor failure determination device for a vehicle according to claim 1, The control device, when performing the first control in response to the issuance of the vehicle start request, closes an external charging contactor that is different from the external charging contactor that was closed when the first control was performed in response to the previous vehicle start request, is characterized in that

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, The control 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 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.

5. The vehicle contactor failure determination device according to any one of claims 1 to 4, 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.

6. 6. The contactor failure determination device for a vehicle according to claim 5, 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.

7. 7. The contactor failure determination device for a vehicle according to claim 5 or 6, 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.

8. The vehicle contactor failure determination device according to any one of claims 5 to 7, 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.

9. The vehicle contactor failure determination device according to any one of claims 1 to 8, The control device After the third control is performed, a sixth control is performed in a state in which the first circuit and the battery are electrically connected, to open the external charging contactor that was closed when the first control was performed; a contactor failure determination device for a vehicle, characterized in that when it is determined that the other external charging contactor has failed in a closed state, if the detection device detects that the voltage of the second circuit does not decrease after the sixth control is performed, it determines that each of the external charging contactors has failed in a closed state.

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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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 a vehicle start request that is a request to start a vehicle is issued, a first control is implemented to close one of the external charging contactors, a second control is implemented to close the pre-charge contactor after the first control is implemented, and a third control is implemented to close the second main contactor after the second control is implemented, and when the detection device detects that the voltage of the second circuit has increased after the third control is implemented, it is determined that the other external charging contactor is in a closed state and has failed; A vehicle contactor failure determination device characterized in that, when the first control is performed in response to a vehicle start request being issued, an external charging contactor different from the external charging contactor that was closed when the first control was performed in response to the previous vehicle start request is closed.

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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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 a vehicle start request that is a request to start a vehicle is issued, a first control is performed to close one of the external charging contactors, a second control is performed to close the pre-charge contactor after the first control is performed, and a third control is performed to close the second main contactor after the second control is performed; When the detection device detects an increase in the voltage of the second circuit after the third control is performed, it is determined that the other external charging contactor has a fault in a closed 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.

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 or disconnects the electrical connection between one of the positive and negative terminals and the first circuit, a second main contactor that connects or 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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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 a vehicle start request is issued, which is a request to start a vehicle, a first control is implemented to close one of the external charging contactors, and after the first control is implemented, a second control is implemented to close the pre-charge contactor, and after the second control is implemented, a third control is implemented to close the second main contactor, and when the detection device detects that the voltage of the second circuit has increased after the third control is implemented, it is determined that the other external charging contactor is in a closed state and has failed, 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.

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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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 a vehicle start request is issued, which is a request to start the vehicle, a first control is performed to close one of the external charging contactors; After the first control is performed, a second control is performed to close the precharge contactor; After the second control is performed, a third control is performed to close the second main contactor; when the detection device detects an increase in the voltage of the second circuit after the third control is performed, it is determined that the other external charging contactor has failed in a closed state; After the third control is performed, a sixth control is performed in a state in which the first circuit and the battery are electrically connected, to open the external charging contactor that was closed when the first control was performed; a contactor failure determination device for a vehicle, characterized in that when it is determined that the other external charging contactor has failed in a closed state, if the detection device detects that the voltage of the second circuit does not decrease after the sixth control is performed, it determines that each of the external charging contactors has failed in a closed state.

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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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, when a vehicle start request that is a request to start the vehicle is issued, performs a first control to close one of the external charging contactors, performs a second control to close the pre-charge contactor 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 has increased after performing the third control, determines that the other external charging contactor has failed in a closed 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 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 connect and disconnect the electrical connections between the positive side lines of the first circuit and the negative side lines of the second circuit; a detection device capable of detecting an increase or decrease in voltage of the second circuit; a control device that controls the first main contactor, the second main contactor, the pre-charge contactor, and the external charging contactors so that these contactors are open while the vehicle is stopped; 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; When a vehicle start request that is a request to start a vehicle is issued, the control device performs a first control to close one of the external charging contactors, performs a second control to close the pre-charge contactor 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 has increased after performing the third control, determines that the other external charging contactor is in a closed state and has failed; 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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