JP7213649B2 - Relay diagnosis device for electric vehicles - Google Patents

Description

The present invention relates to a relay diagnostic device for an electric vehicle.

2. Description of the Related Art Electric vehicles such as EVs (Electric Vehicles) and HEVs (Hybrid Electric Vehicles) include an inverter that drives a traction motor and a battery that stores electric power for running. The inverter and the battery are connected via a power line, and the power line is provided with a system main relay capable of opening and closing an electric circuit. Furthermore, such an electric vehicle may be provided with a device such as a charger that is connected to the battery. Such equipment is connected to a branch line branched from the power supply line. A device relay is provided on the branch line, and the device can be connected to or disconnected from the battery by switching the device relay.

It is recommended that relays installed in power transmission lines, such as system main relays and equipment relays, be appropriately diagnosed to determine whether contacts have been welded due to unregulated use or the like. Patent Literature 1 discloses an abnormality diagnosis device for determining whether or not a charging relay is welded in a vehicle equipped with a power control system having a main relay and a charging relay.

JP 2013-219873 A

When diagnosing relay welding, if there is no ingenuity, a large inrush current may flow from the battery to the device via the relays when the relays are switched in the diagnosis process, deteriorating one of the relays. For this reason, when diagnosing a relay, normally, the relay to be diagnosed or the relay not to be diagnosed including the system main relay is switched as appropriate to prevent a large current from flowing through any of the relays during diagnosis. state is created.

However, if the system main relay and the device relay are switched as appropriate each time a device relay welding diagnosis is performed to create a state suitable for diagnosis, this relay switching is performed for the number of welding diagnosis, and the overall relay A problem arises that the number of times of switching is increased. In particular, when diagnosing the welding of multiple relays at the same time, after diagnosing the welding of the first relay, the multiple relays are switched as appropriate to change the state of the connection terminals of the device to the discharged state or the state in which voltage is applied. may need to be reset to Then, after resetting, a state suitable for diagnosis is created so that a large current does not flow through any of the relays in the welding diagnosis of the second relay, and the welding diagnosis of the second relay is performed. These will further increase the number of times the relay is switched. An increase in the total number of switching times of the relay causes a problem that the service life of the relay is shortened.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a relay diagnostic apparatus for an electric vehicle that can diagnose welding of a relay while suppressing an increase in the number of times the relay is switched.

The invention according to claim 1,
A relay diagnosis device for an electric vehicle mounted on an electric vehicle having a first relay set for opening and closing a pair of power lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power lines. There is
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period ,
The first relay set includes a first system main relay and a second system main relay for opening and closing the pair of power lines, respectively, and a precharge resistor connected in series to an electric circuit connected in parallel with the first system main relay. and a precharge relay;
the second relay set includes two device relays for opening and closing the pair of branch lines, respectively;
The diagnosis processing unit keeps the device relay to be diagnosed and the first system main relay to be cut off during welding diagnosis during the processing period for starting the system, and keeps the device relay to be diagnosed and the second system main relay to be cut off. It is characterized in that the system main relay and the precharge relay are switched from disconnection to connection control, and then the voltage between the pair of branch lines is inspected to obtain the result of welding diagnosis .

The invention according to claim 2 is the relay diagnosis device for an electric vehicle according to claim 1,
the second relay set includes two device relays for opening and closing the pair of branch lines, respectively;
The diagnosis processing unit performs a welding diagnosis of the second relay set using the precharge relay during the processing period for starting the system, and activates the precharge relay during the processing period for ending use of the branch line. The welding diagnosis of the second relay set is performed without using the second relay set.

The invention according to claim 3 is the relay diagnosis device for an electric vehicle according to claim 1 or claim 2 ,
The diagnosis processing unit maintains control of connection of the first system main relay, the second system main relay, and the device relays not subject to diagnosis during the welding diagnosis during the processing period for the end of use of the branch line. It is characterized by switching the target device relay from connection to disconnection control, then inspecting the voltage between the pair of branch lines, and obtaining the welding diagnosis result.

The invention according to claim 4 ,
4. The electric vehicle according to any one of claims 1 to 3 , wherein the power supply line is connected to a battery that supplies power for running, and the branch line is connected to a charger that charges the battery. The relay diagnostic device for an electric vehicle according to 1.,
It is characterized by further comprising a schedule processing unit that determines a schedule for welding diagnosis of the second relay set based on the usage history of the charger.

The invention according to claim 5 ,
A first relay set for opening and closing a pair of power supply lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power supply lines, to supply power for running to the power supply lines. A relay diagnosis device for an electric vehicle mounted on an electric vehicle to which a battery is connected and a charger for charging the battery is connected to the branch line,
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period,
a schedule processing unit that determines a schedule for diagnosing welding of the second relay set based on the usage history of the charger;
The schedule processing unit is characterized in that the schedule for the welding diagnosis of the second relay set is changed based on whether or not there is an abnormal termination of the charging process using the charger.

The invention according to claim 6 ,
A first relay set for opening and closing a pair of power supply lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power supply lines, to supply power for running to the power supply lines. A relay diagnosis device for an electric vehicle mounted on an electric vehicle to which a battery is connected and a charger for charging the battery is connected to the branch line,
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period,
a schedule processing unit that determines a schedule for diagnosing welding of the second relay set based on the usage history of the charger;
The schedule processor changes the schedule of the welding diagnosis of the second relay set based on the SOC of the battery.

The invention according to claim 7 ,
A first relay set for opening and closing a pair of power supply lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power supply lines, to supply power for running to the power supply lines. A relay diagnosis device for an electric vehicle mounted on an electric vehicle to which a battery is connected and a charger for charging the battery is connected to the branch line,
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period,
a schedule processing unit that determines a schedule for diagnosing welding of the second relay set based on the usage history of the charger;
The schedule processing unit is characterized by changing the schedule of the welding diagnosis of the second relay set during the processing period for starting the system based on the position information of the electric vehicle when the system is terminated.

When the system of the electric vehicle is started, the first relay set and the second relay set are in a predetermined switching state, and the device connected to the branch line is in a discharged state. Furthermore, the device connected to the power supply line transitions from a state in which the connection terminal is discharged to a state in which the power supply voltage is input. In this way, by using the predetermined state and the transition of the predetermined state at system start-up, the number of times the relay is switched can be suppressed, and there is no risk of a large current flowing through the relay. It is possible to diagnose welding of individual relays. Similarly, at the end of use of the branch line, the first relay set and the second relay set are in a predetermined switching state, and the equipment connected to the branch line is discharged from the state where the power supply voltage is applied to the connection terminals. state. Using predetermined states and predetermined state transitions in this way reduces the number of times the relays are switched and prevents welding of a single relay in the second set of relays without the risk of large currents flowing through the relays. Diagnosis can be made.

Therefore, in the present invention, the diagnostic processing unit utilizes the processing period for system startup, the processing period for ending use of the branch line, or both of these processing periods, and determines the number of relays within one in one processing period. Carry out welding diagnosis. Therefore, in each welding diagnosis, the welding diagnosis of the device relay can be realized in a state suitable for the welding diagnosis so as to suppress the increase in the number of switching times of the relay and prevent a large current from flowing through the relay. As a result, welding diagnosis of the relay can be performed while suppressing an increase in the total number of times the relay is switched.

1 is a block diagram showing an electric vehicle equipped with a relay diagnosis device according to an embodiment of the invention; FIG. 6 is a flowchart showing an example of scheduling processing executed by a scheduling processing unit; FIG. 11 is a timing chart showing an example of welding diagnosis processing using a processing period of system startup; FIG. FIG. 11 is a timing chart showing an example of welding diagnosis processing using a processing period for ending use of a branch line; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an electric vehicle equipped with a relay diagnosis device according to an embodiment of the invention.

The electric vehicle 1 according to this embodiment is an EV, HEV, or the like. The electric vehicle 1 includes a travel motor 11 that powers the drive wheels 2, an inverter 12 that drives the travel motor 11, a battery 13 that stores electric power for travel and supplies electric power to the inverter, and external components of the electric vehicle 1. A charger 14 that charges a battery 13 using a power source, a navigation device 20 and a control device 30 are provided.

The battery 13 and the inverter 12 are connected via a pair of power supply lines L0. A first relay set B1 is provided on the pair of power lines L0. The first relay set B1 includes a first system main relay SMR1 capable of switching between connecting and disconnecting one power line L0, and a second system main relay SMR2 capable of switching between connecting and disconnecting the other power line L0. . Breaking and connecting a relay may be called opening and closing. Further, the first relay set B1 includes a precharge relay PR and a precharge resistor R1 which are connected in series with each other in an electric circuit connected in parallel with the first system main relay SMR1.

The precharge relay PR and the precharge resistor R1 make it possible to avoid a large inrush current flowing between the battery 13 and the inverter 12 or between the battery 13 and the charger 14 when switching the power line L0 from cutoff to connection. It is a configuration for For example, by connecting the precharge relay PR and switching the second system main relay SMR2 to connection before switching the first system main relay SMR1 to connection, a current is supplied from the battery 13 to the inverter 12 via the precharge relay PR. Therefore, the connection terminal of the inverter 12 can be gently precharged. After precharging, the first system main relay SMR1 is switched to connect, and the precharge relay PR is switched to disconnect, so that the battery 13 and the inverter 12 can be connected without a large rush current.

The charger 14 is connected to a pair of branch lines L1 branched from a pair of power supply lines L0. A second relay set B2 is provided on the pair of branch lines L1. The second relay set B2 includes two equipment relays SR each capable of switching the pair of branch lines L1 to connect or disconnect. Breaking and connecting a relay may be called opening and closing. The second relay set B2 does not include the precharge relay PR and the precharge resistor R1, and when the connection terminal of the charger 14 needs to be precharged, the precharge function of the first relay set B1 is used. Prejudgement can be realized. As a result, the number of parts can be reduced and the manufacturing cost can be reduced.

The battery 13 is, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery, and outputs a voltage higher than the voltage of the auxiliary battery that drives the auxiliary or accessory device. The battery 13 may also be called a high voltage battery or a traction battery.

The navigation device 20 includes a positioning device that measures the current position and a display device that displays map information, and provides route information to the driver. Furthermore, the navigation device 20 provides positioning information to the control device 30 .

The control device 30 includes a motor control unit 31 that controls the inverter 12 and drives the travel motor 11 according to the driver's driving operation, and a battery that manages the state of the battery 13 (SOC (State of Charge), voltage, temperature, etc.). It includes a management unit 32 and a vehicle control unit 33 that controls the entire system of the electric vehicle 1 . The vehicle control unit 33 also performs charging processing of the battery 13 via the charger 14 . The control device 30 includes a plurality of ECUs (Electronic Control Units), and the plurality of ECUs cooperate through communication to control the operation of each section.

Each ECU of the control device 30 includes a CPU (Central Processing Unit), a storage device storing control programs and control data, and a RAM (Random Access Memory) in which the CPU develops data. In the ECU, a plurality of functional modules are realized by the CPU executing a control program. The functional modules implemented in the vehicle control unit 33 include a diagnosis processing unit 36 that performs welding diagnosis of the second relay set B2, and a schedule processing unit 37 that sets a schedule for welding diagnosis of the second relay set B2. . The vehicle control unit 33 corresponds to an example of a relay diagnosis device according to the invention.

<Schedule processing>
FIG. 2 is a flowchart showing an example of scheduling processing executed by the scheduling processing unit 37. As shown in FIG. The schedule processing unit 37 executes the schedule processing shown in FIG. 2 at predetermined timings during the activation of the system of the electric vehicle 1 and after the termination of the system. “During system startup” means a period in which the first relay set B1 is switched to the connection based on the power supply or ignition of the electric vehicle 1 being turned on. The charging process via the charger 14 is also included in the system start-up. "After the system is terminated" means a period in which the first relay set B1 is switched off based on the power source or ignition of the electric vehicle 1 being turned off. Since power for control is supplied from the auxiliary device battery even after the system is terminated, the schedule processing unit 37 can execute the schedule processing.

When the schedule process is started, the schedule processor 37 acquires the usage history of the charger 14 stored in the vehicle controller 33 (step S1). For example, the vehicle control unit 33 stores charging history information in the storage device each time the battery 13 is charged using the charger 14 . In step S<b>1 , the usage history of the charger 14 can be acquired by the schedule processing unit 37 reading the charging history information from the storage device.

Next, the schedule processing unit 37 determines whether or not there is a history of an abnormal termination of the charging process due to overvoltage, overcurrent, or the like from the charging history information (step S2).

Subsequently, the schedule processing unit 37 acquires SOC information of the battery 13 managed by the battery management unit 32 of the control device 30 (step S3).

Furthermore, if the current time is after the system is terminated, the schedule processing unit 37 acquires the position information of the electric vehicle 1 at the time when the system is terminated. etc.) are collated (step S4). The position information is acquired from the navigation device 20 by the vehicle control unit 33 when the electric vehicle 1 is stopped, and is stored in the storage device, so that the schedule processing unit 37 can use it in step S4.

Then, the schedule processing unit 37 determines a schedule for diagnosing welding of the individual device relays SR of the second relay set B2 based on the information of steps S1 to S4 (step S5).

Here, the schedule processing unit 37 determines the timing of the welding diagnosis for the device relay SR during the processing period for starting the system, the processing period for ending the use of the charger 14 (that is, ending the use of the branch line L1), or both. Limit processing time. This processing period is hereinafter referred to as a "specific processing period". Further, the schedule processing unit 37 limits the welding diagnosis to be performed for no more than one device relay SR in one specific processing period. In other words, the welding diagnosis for any one device relay SR is performed during one specific processing period, or the welding diagnosis for the device relay SR is not performed during one specific processing period. .

In step S5, the schedule processing unit 37 determines the schedule for the welding diagnosis within the above limit. For example, if there is no abnormality in step S2, the SOC in step S3 is at a normal level or higher, and the verification result in step S4 is not in the chargeable position, each device relay SR is Determine the schedule so that the welding diagnosis is performed. For example, after the charger 14 has been used five times, the welding diagnosis of one device relay SR is performed at the end of use of the charger 14, and the welding diagnosis of the other device relay SR is performed when the system is started after that. is.

Further, in step S5, if there is an abnormality in step S2, the schedule processing unit 37 performs welding diagnosis of the two device relays SR in the following two specified processing periods regardless of the number of times the charger 14 is used. reschedule so that Similarly, when the SOC in step S3 is at a level that requires charging, the schedule processing unit 37 makes a change such as reducing the number of times the charger 14 is used for welding diagnosis, for example. For example, the schedule may be changed from a schedule in which the welding diagnosis is performed once every five times of use to a schedule in which the welding diagnosis is performed in the next specific processing period if the equipment is used twice or more.

Further, in step S5, the schedule processing unit 37 schedules the welding diagnosis of the device relay SR to be performed during the specific processing period of the next system start-up if there is a position at the time of system termination among the chargeable positions in step S4. change.

After that, the schedule processor 37 stores the determined schedule in the storage device (step S6), and completes one schedule process. The diagnosis processing unit 36 executes welding diagnosis of the device relay SR according to the schedule stored in the storage device.

It should be noted that the restriction that the welding diagnosis is performed for one or less device relays SR in one specific processing period does not have to be absolute. For example, in the normal mode, the schedule is determined with such restrictions, while in the fail-safe diagnosis mode, the schedule is determined so that the welding diagnosis of the device relay SR can be performed at any time without such restrictions. may

<Welding Diagnosis Processing Using System Startup Processing Period>
FIG. 3 is a timing chart showing an example of welding diagnosis processing using the processing period of system startup. In FIG. 3, "VL" is the voltage between the pair of power supply lines L0 on the equipment side of the first relay set B1, and "Vchg" is the voltage between the pair of branch lines L1 on the charger 14 side of the second relay set B2. indicates FIG. 3 shows an example in which the equipment relay SR of the anode is the object of diagnosis, and the dashed line shows the change when the equipment relay SR of the object of diagnosis is welded. In FIG. 3, connection of the relay is indicated as ON, and disconnection is indicated as OFF.

Before system startup, as shown at timing t1 in FIG. 3, the first system main relay SMR1, the second system main relay SMR2, the precharge relay PR, and the two device relays SR are in a controlled state of disconnection. If the equipment relay SR of the anode to be diagnosed is welded, the equipment relay SR is connected as indicated by the dashed line even if the control is switched to cutoff. Further, the connection terminal of inverter 12 and the connection terminal of charger 14 are in a discharging state, and voltage VL across power supply line L0 and voltage Vchg across branch line L1 are at a low level (0 V).

At subsequent timings t2 to t4, the diagnostic processing unit 36 sequentially switches the control to connect the device relay SR of the cathode, connect the second system main relay SMR2, and connect the precharge relay PR. Then, as shown at timings t4 to t5, the connection terminal of the inverter 12 is gradually precharged through the precharge resistor R1, and the voltage VL rises.

Here, if the device relay SR to be diagnosed is not welded, the connection terminal of the charger 14 is not precharged, so the voltage Vchg remains zero. On the other hand, if the device relay SR to be diagnosed is welded, the connection terminal of the charger 14 is also precharged, and the voltage Vchg rises similarly to the voltage VL. Therefore, at timing t5, the diagnosis processing unit 36 compares (inspects) the voltage Vchg with the voltage VL, thereby obtaining a diagnosis result as to whether or not the device relay SR to be diagnosed is welded.

After that, the diagnostic processing unit 36 sequentially switches the cathode device relay SR, the precharge relay PR, and the second system main relay SMR2 to the preceding stage of timings t5 to t7, thereby performing welding diagnosis processing. exit. Thereafter, at timings t7 and t8, the vehicle control unit 33 switches the connection of the second system main relay SMR2 and the precharge relay PR. 1 The system main relay SMR1 is switched to connected and the precharge relay PR is switched to disconnected to complete system start-up. Note that switching of the relays at timings t6 to t8 is omitted, and the vehicle control unit 33 performs only connection of the first system main relay SMR1 and switching of disconnection of the precharge relay PR at timing t9 to complete the system start-up processing. good too.

The example in FIG. 3 is an example in which the anode device relay SR is the diagnosis target. The switching operation of the device relay SR may be exchanged with the switching operation of the device relay SR. By this switching operation, it is possible to diagnose whether or not the device relay SR of the cathode is welded in the voltage comparison (inspection) process at timing t5.

<Welding Diagnosis Processing Utilizing Processing Period for Termination of Use of Charger 14>
FIG. 4 is a timing chart showing an example of welding diagnosis processing using the processing period for ending use of charger 14 . 3, "VL" is the voltage between the pair of power lines L0 on the device side of the first relay set B1, and "Vchg" is the voltage of the pair of power lines L0 on the charger 14 side of the second relay set B2. The voltage across the branch line L1 is shown. FIG. 4 shows an example in which the equipment relay SR of the cathode is targeted for diagnosis. A dashed line indicates a change when the device relay SR to be diagnosed is welded. In FIG. 4, connection of the relay is indicated as ON, and disconnection is indicated as OFF.

Before the end of use of the charger 14, the first system main relay SMR1, the second system main relay SMR2, and the two device relays SR are in the connection control state, as shown at timing t10 in FIG. is in the control state of blocking. Further, the connection terminal of the inverter 12 and the connection terminal of the charger 14 are in a state where the power supply voltage is applied, and the voltage VL across the power supply line L0 and the voltage Vchg across the branch line L1 are at a high level (output voltage of the battery 13). )It is in.

The diagnosis processing unit 36 starts welding diagnosis processing based on the end of use of the charger 14, and first switches the device relay SR of the cathode to be diagnosed to cutoff control (timing t11). Here, if the device relay SR of the cathode to be diagnosed is not welded, the voltage output from the battery 13 to the connection terminal of the charger 14 is interrupted by switching at timing t11, and the charger 14 discharges based on this interruption. , the voltage Vchg of the connection terminal of the charger 14 gradually drops at the subsequent timing t12.

On the other hand, if the cathode device relay SR to be diagnosed is welded, the cathode device relay SR maintains the connected state as indicated by the dashed line even if the control is switched to cutoff at timing t11, and the cathode device relay SR remains connected at timing t12. No drop in voltage Vchg occurs. Therefore, the diagnostic processing unit 36 compares the voltage Vchg with the voltage VL at timing t13 to obtain a diagnostic result as to whether or not the cathode equipment relay SR is welded. Then, the diagnostic processing unit 36 ends this diagnostic processing.

After that, the vehicle control unit 33 switches the anode device relay SR to cutoff control (timing t14). (after timing t15). As a result, the voltage VL of the power supply line L0 is also discharged and lowered, and the process of ending the use of the charger 14 is completed.

The example in FIG. 4 is an example in which the cathode device relay SR is the diagnosis target. The switching operation of the device relay SR may be exchanged with the switching operation of the device relay SR. This switching operation makes it possible to diagnose whether or not the anode equipment relay SR is welded in the voltage comparison (inspection) process at timing t13.

According to the schedule determined by the schedule processing unit 37, the diagnosis processing unit 36 performs the welding diagnosis during the processing period for starting the system and the welding diagnosis during the processing period for ending the use of the charger 14 described above. As a result, it is possible to diagnose whether or not the two device relays SR are welded with a small number of relay switching times.

As described above, according to the electric vehicle 1 and the vehicle control unit 33 functioning as the relay diagnosis device of the present embodiment, the diagnosis processing unit 36 performs A welding diagnosis is made for the equipment relays SR one by one. In other words, welding diagnosis of a plurality of device relays SR is divided into a plurality of specific processing periods so that diagnosis of not more than one device relay SR is performed in one specific processing period. As a result, even if welding diagnosis is performed frequently, the number of relay switching times increased for the welding diagnosis does not increase among the number of switching times of the relays of the first relay set B1 and the second relay set B2. Therefore, it is possible to prevent a situation in which the total number of times the first relay set B1 and the second relay set B2 are switched for welding diagnosis is increased and the service life is shortened.

Furthermore, according to the electric vehicle 1 and the vehicle control unit 33 of the present embodiment, the diagnosis processing unit 36 uses the precharge relay PR of the first relay set B1 to diagnose the welding of the device relay SR during the system activation processing period. I do. Further, the diagnosis processing unit 36 diagnoses the welding of the device relay SR without using the precharge relay PR during the processing period for ending the use of the charger 14 . Therefore, the precharge relay PR only needs to be included in the first relay set B1, and it becomes unnecessary to separately provide the precharge relay PR in the second relay set B2. As a result, it is possible to reduce the number of components of the electric power system of the electric vehicle 1 and reduce the manufacturing cost.

Furthermore, according to the electric vehicle 1 and the vehicle control unit 33 of the present embodiment, the diagnosis processing unit 36 first disconnects the device relay SR to be diagnosed and the first system main relay SMR1 in the welding diagnosis at the time of system startup. remain in the control of Then, the diagnosis processing unit 36 switches the device relay SR, the second system main relay SMR2, and the precharge relay PR, which are not to be diagnosed, from disconnection to connection control. VL is compared to diagnose welding of the device relay SR. According to such a diagnostic method, welding diagnosis of one device relay SR can be realized only by adding a small number of switching times of relays for welding diagnosis to the switching of relays required at system start-up.

Further, according to the electric vehicle 1 and the vehicle control unit 33 of the present embodiment, the diagnosis processing unit 36, in the welding diagnosis at the end of use of the charger 14, firstly performs the first system main relay SMR1, the second system main relay SMR1, and the second system main relay SMR1. SMR2 and non-diagnosed device relay SR remain under connection control. Then, the diagnostic processing unit 36 switches the device relay SR to be diagnosed to cutoff control, and then compares the voltage Vchg of the branch line L1 and the voltage VL of the power supply line L0 to diagnose the welding of the device relay SR. . According to such a diagnosis method, welding diagnosis of one device relay SR can be realized only by switching the necessary relays at the end of use of the charger 14, and it is not necessary to increase the number of times of relay switching for welding diagnosis. Absent.

Further, according to the electric vehicle 1 and the vehicle control unit 33 of the present embodiment, the schedule processing unit 37 determines the welding diagnosis schedule for the device relay SR based on the usage history of the charger 14 . For example, the welding diagnosis schedule is determined so that if the number of times of use of the charger 14 is large, the welding diagnosis of the device relay SR will be frequent, and if the number of times of use is small, the welding diagnosis of the device relay SR will be small. As a result, welding diagnosis can be performed efficiently, and an increase in the number of times the relay is switched due to unnecessary welding diagnosis can be suppressed.

Furthermore, according to the electric vehicle 1 and the vehicle control unit 33 of the present embodiment, the schedule processing unit 37 determines whether or not there is an abnormal termination of the charging process, the SOC of the battery 13, and the system shutdown time of the electric vehicle 1. Reschedule welding diagnosis for the second relay set B2 based on the position information. As a result, when an abnormality in the second relay set B2 is suspected due to abnormal termination of the charging process, when the SOC is low and the charger 14 is expected to be used frequently, or when the electric vehicle 1 stops at a chargeable location and charges The frequency of welding diagnosis can be increased, for example, when the container 14 is expected to be used. As a result, welding diagnosis can be performed efficiently according to the situation, and an increase in the number of times the relays are switched due to unnecessary welding diagnosis can be suppressed.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. For example, in the above embodiment, the procedure for diagnosing welding when the system is terminated and the procedure for diagnosing welding when the use of the charger 14 is terminated are shown using the timing charts of FIGS. These are merely examples and are not intended to limit the invention. For example, the illustrated timing chart includes a timing chart in which the switching order of each relay can be changed. Also, the voltage Vchg can be inspected by comparing the voltage Vchg with a predetermined voltage threshold, etc., without comparing the voltage Vchg and the voltage VL. The example of the welding diagnosis schedule determined and changed by the schedule processor 37 is also merely an example, and does not limit the present invention.

Further, in the above embodiment, an example in which the charger 14 is connected to the branch line L1 has been shown, but other devices are connected to the branch line L1, and the second relay set B2 switches between connection and disconnection with the battery 13. It may be configured to be possible. Also, a plurality of sets of the branch line L1 and the second relay set B2 may be provided. Also, the precharge relay and the precharge resistor may be connected in parallel to the second system main relay. Other details shown in the embodiments can be changed as appropriate without departing from the scope of the invention.

1 Electric Vehicle 11 Traveling Motor 12 Inverter 13 Battery 14 Charger L0 Power Line L1 Branch Line B1 First Relay Set SMR1 First System Main Relay SMR2 Second System Main Relay PR Precharge Relay R1 Precharge Resistor B2 Second Relay Set SR Equipment relay 30 Control device 33 Vehicle control unit (relay diagnosis device)
36 diagnostic processing unit 37 schedule processing unit

Claims (7)

A relay diagnosis device for an electric vehicle mounted on an electric vehicle having a first relay set for opening and closing a pair of power lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power lines. There is
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period ,
The first relay set includes a first system main relay and a second system main relay for opening and closing the pair of power lines, respectively, and a precharge resistor connected in series to an electric circuit connected in parallel with the first system main relay. and a precharge relay;
the second relay set includes two device relays for opening and closing the pair of branch lines, respectively;
The diagnosis processing unit keeps the device relay to be diagnosed and the first system main relay to be cut off during welding diagnosis during the processing period for starting the system, and keeps the device relay to be diagnosed and the second system main relay to be cut off. A relay diagnosis device for an electric vehicle, characterized by switching control of the system main relay and the precharge relay from disconnection to connection control, and then inspecting the voltage between the pair of branch lines to obtain a welding diagnosis result . The diagnosis processing unit performs a welding diagnosis of the second relay set using the precharge relay during a processing period for starting the system, and performs a welding diagnosis for the second relay set during a processing period for ending use of the branch line. 2. The relay diagnosis device for an electric vehicle according to claim 1, wherein the welding diagnosis of the second relay set is performed without using the relay set. The diagnosis processing unit maintains control of connection of the first system main relay, the second system main relay, and the device relays not subject to diagnosis during the welding diagnosis during the processing period for the end of use of the branch line. 3. The electric motor according to claim 1 or 2 , wherein the device relay to be controlled is switched from connection to disconnection control, and then the voltage between the pair of branch lines is inspected to obtain the welding diagnosis result. Vehicle relay diagnostic device. 4. The electric vehicle according to any one of claims 1 to 3 , wherein the power supply line is connected to a battery that supplies power for running, and the branch line is connected to a charger that charges the battery. The relay diagnostic device for an electric vehicle according to 1.,
A relay diagnosis apparatus for an electric vehicle, further comprising a schedule processing unit that determines a schedule for welding diagnosis of the second relay set based on the usage history of the charger. A first relay set for opening and closing a pair of power supply lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power supply lines, to supply power for running to the power supply lines. A relay diagnosis device for an electric vehicle mounted on an electric vehicle to which a battery is connected and a charger for charging the battery is connected to the branch line,
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period,
a schedule processing unit that determines a schedule for diagnosing welding of the second relay set based on the usage history of the charger;
The relay diagnosis of an electric vehicle, wherein the schedule processing unit changes the schedule of welding diagnosis of the second relay set based on whether or not there is an abnormal termination of the charging process using the charger. Device. A first relay set for opening and closing a pair of power supply lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power supply lines, to supply power for running to the power supply lines. A relay diagnosis device for an electric vehicle mounted on an electric vehicle to which a battery is connected and a charger for charging the battery is connected to the branch line,
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period,
a schedule processing unit that determines a schedule for diagnosing welding of the second relay set based on the usage history of the charger;
The relay diagnosis device for an electric vehicle, wherein the schedule processing unit changes the schedule of the welding diagnosis of the second relay set based on the SOC of the battery. A first relay set for opening and closing a pair of power supply lines, and a second relay set for opening and closing a pair of branch lines branched from the pair of power supply lines, to supply power for running to the power supply lines. A relay diagnosis device for an electric vehicle mounted on an electric vehicle to which a battery is connected and a charger for charging the battery is connected to the branch line,
a diagnosis processing unit that operates one of the first relay set and the second relay set, inspects the voltage between the pair of branch lines, and performs welding diagnosis of the second relay set; ,
The diagnosis processing unit diagnoses welding of individual relays included in the second relay set during a processing period for starting the system of the electric vehicle, a processing period for ending use of the branch line, or both of these processing periods. and perform a welding diagnosis of not more than one of the relays in one processing period,
a schedule processing unit that determines a schedule for diagnosing welding of the second relay set based on the usage history of the charger;
The relay for an electric vehicle, wherein the schedule processing unit changes the schedule for the welding diagnosis of the second relay set during the processing period for starting the system based on position information at the time of system shutdown of the electric vehicle. diagnostic equipment.

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