In-vehicle system and junction box

Abstract

In-vehicle system (2) which includes the following: a junction box (21, 22) arranged on the front and / or rear of a battery pack (20) provided in an electric vehicle (1); and a first voltage sensing unit (204a) that detects a voltage value of the battery pack (20), wherein the junction box (21, 22) has the following features: a first relay unit (211, 221) which is electrically connected to the battery pack (20) and a drive source (4, 6) and switches the state of the battery pack (20) and the drive source (4, 6) into an energy-distributed state or a switched-off state by means of an on / off operation, a second voltage sensing unit (213, 223) which is electrically connected in parallel to the battery pack (20) and detects a voltage value of the battery pack (20), and a controller (217, 227) configured to control the on / off switching operation of the first relay unit (211, 221), and wherein the controller (217, 227) monitors whether the first relay unit (211, 221), the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223) each exhibit an anomaly or not, based on a sensing result that is each detected by the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223) when the first relay unit (211, 221) performs the on / off operation.

Description

[0001] The present invention relates to a vehicle-internal system and a junction box.

[0002] A conventionally known technique for an electric vehicle involves a battery pack comprising several battery blocks connected in series, with a terminal box on one side of the battery pack. Electrical power from the battery pack is supplied to a motor by switching a relay located in the terminal box on and off (e.g., Japanese patent application Laid-open No. JP 2020-87661A). This technique monitors the overall voltage within the battery pack based on a voltage reading from a voltage sensor, such as a total voltage monitoring circuit. In this circuit, an electronic battery control unit (ECU) located within the battery pack is connected to the battery pack and the terminal box.

[0003] However, in the Japanese patent application Laid-open No. JP 2020-87 661 A described above, relay anomalies in the junction box are not monitored. Therefore, in the Japanese patent application Laid-open No. JP 2020-87 661 A described above, it was difficult for the battery ECU to determine which of the two was defective if the voltage sensor in the battery pack and / or the relay in the junction box was faulty.

[0004] From US patent 2017 / 0144554A1, it is known to check the switching of contacts in high-voltage electrical systems in vehicles by comparing the voltages on both sides of the switch upon receiving a corresponding control signal and, if necessary, triggering an alarm. German patent DE 102018214658A1 describes an electric vehicle with a high-voltage battery equipped with an interlock switch that opens and closes accordingly for disconnection and connection.

[0005] Therefore, the present invention was implemented in view of the foregoing, and it is an objective of the present invention to provide an in-vehicle system and a junction box that are capable of distinguishing and detecting defects in a voltage sensor and a relay of the junction box.

[0006] To achieve the above-mentioned objective, an in-vehicle system according to one aspect of the present invention comprises a junction box arranged at the front or rear of a battery pack provided in an electric vehicle; and a first voltage sensing unit sensing a voltage value of the battery pack, wherein the junction box comprises a first relay unit, a second voltage sensing unit, and a controller, wherein the first relay unit is electrically connected to the battery pack and a power source and switches the battery pack and the power source to a power-distributed state or an off state by means of an on / off operation, wherein the second voltage sensing unit is electrically connected in parallel to the battery pack and sensing a voltage value of the battery pack, and wherein the controller is configured to control the on / off operation of the first relay unit.and the controller monitors whether the first relay unit, the first voltage sensing unit, and the second voltage sensing unit each exhibit an anomaly or not, based on a sensing result that is captured by the first voltage sensing unit and the second voltage sensing unit, respectively, when the first relay unit performs the on / off switching operation.

[0007] To achieve the aforementioned objective, a junction box arranged on the front or rear of a battery pack provided in an electric vehicle and comprising a first voltage sensing unit capable of detecting a voltage value, according to a further aspect of the present invention, comprises a first relay unit, a second voltage sensing unit, and a controller, wherein the first relay unit is electrically connected to the battery pack and a power source and switches the battery pack and the power source to a power-distributed state or an off state by means of an on / off operation, wherein the second voltage sensing unit is electrically connected in parallel to the battery pack and detects a voltage value of the battery pack, and wherein the controller is configured to control the on / off operation of the first relay unit.wherein the controller monitors, based on a detection result, whether the first relay unit, the first voltage detection unit and the second voltage detection unit each exhibit an anomaly or not, wherein the detection result is detected by the first voltage detection unit and the second voltage detection unit respectively when the first relay unit performs the on / off switching operation.

[0008] The above and other aims, features, advantages and the technical and industrial significance of this invention will be more easily understood by studying the following detailed description of currently preferred embodiments of the invention when viewed in conjunction with the accompanying drawings. Brief description of the drawings Fig. Figure 1 is a diagram that briefly illustrates the configuration of a vehicle to which an in-vehicle system according to a first embodiment is attached; Fig. Figure 2 is a diagram that schematically illustrates a detailed configuration example of a battery pack and a front junction box in the vehicle's internal system according to the first embodiment; Fig. Figure 3 is a diagram that schematically illustrates a detailed configuration example of the front junction box according to the first embodiment; Fig. Figure 4 is a flowchart representing an operational example performed by the vehicle's in-vehicle system according to the first embodiment; Fig. Figure 5 is a diagram that represents an example of the contents of a defect determination procedure performed by a second MCU according to the first embodiment; Fig. Figure 6 is a diagram that briefly illustrates a configuration of a vehicle to which an in-vehicle system according to a second embodiment is attached; Fig. Figure 7 is a diagram schematically showing a detailed configuration example of a battery pack, a front junction box, and a rear junction box in the vehicle's internal system according to the second embodiment; and Fig. Figure 8 is a diagram that provides an example of the contents of a defect determination procedure performed by the vehicle's internal system according to the second embodiment. Detailed description of preferred embodiments: First embodiment; Vehicle configuration

[0009] With reference to the drawings, a vehicle-internal system according to a first embodiment is described. Fig. Figure 1 is a diagram that briefly illustrates the configuration of a vehicle to which an in-vehicle system according to the first embodiment is attached.

[0010] A vehicle 1, which is in Fig. The vehicle shown in Figure 1 is equipped with an in-vehicle system 2, a front power control unit 3 (hereinafter referred to simply as "front PCU 3 (PCU: Power Control Unit)") located at the front of the vehicle 1, a front motor 4 located at the front of the vehicle 1, a rear power control unit 5 (hereinafter referred to simply as "rear PCU 5 (PCU: Power Control Unit)") located at the rear of the vehicle 1, a rear motor 6 located at the rear of the vehicle 1, drive wheels 7, a fast charging port 8, a normal charging port 9, a sensor group 10, a display unit 11, and a vehicle control unit 12.

[0011] The vehicle's internal system 2 is attached to vehicle 1 as its energy source and supplies electrical energy to drive sources such as the front motor 4 and the rear motor 6. The vehicle's internal system 2 is attached to an electric vehicle such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV). The vehicle's internal system 2 is charged with electrical energy supplied by an external charger via the fast-charging port 8 or the standard charging port 9 (described later) and delivers the charged electrical energy to a load component.The vehicle's internal system 2 is charged with electrical energy, supplied, for example, by a fast charger or a standard charger, which serve as external chargers, and delivers this charged electrical energy to the front motor 4 and the rear motor 6, which serve as drive sources. The standard charger, for example, has an output voltage of approximately 200 V. The fast charger has a higher output voltage than the standard charger, for example, approximately 400 V. The standard charger or the fast charger is installed at a charging station or similar device of the vehicle 1 and supplies the vehicle's internal system 2 with electrical energy when the charger is connected to the fast charging port 8 or the standard charging port 9 of the vehicle 1, as described later.

[0012] The vehicle's internal system 2 is equipped with a battery pack 20, a front junction box 21 (hereinafter referred to simply as "front J / B 21") and a rear junction box 22 (hereinafter referred to simply as "rear J / B 22").

[0013] Battery pack 20 is attached to vehicle 1 as its power source. Battery pack 20 comprises a composite battery consisting of many cells (secondary batteries). Specifically, in battery pack 20, each battery block (sometimes called a battery stack) consists of several cells, each electrically connected in series or parallel, and multiple battery blocks are electrically connected in series or parallel to form the composite battery. Each cell is formed using, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery. Battery pack 20 stores the electrical energy to power the front motor 4 and the rear motor 6, supplying electrical energy to the front motor 4 via the front PCU 3 and to the rear motor 6 via the rear PCU 5.The battery pack 20 is charged by receiving the electrical energy generated by the front motor 4 and the rear motor 6 through the front PCU 3 and the rear PCU 5 during regenerative energy generation by the front motor 4 and the rear motor 6, e.g., when the vehicle 1 is braking. It should be noted that a detailed configuration of the battery pack 20 will be described later.

[0014] The front J / B 21 is located at the front longitudinally of the vehicle 1 and electrically connects the battery pack 20, the front PCU 3, and the fast-charging port 8. The front J / B 21 performs an ON / OFF operation in accordance with a control signal from the vehicle control unit 12, thereby switching the electrical connection state between the battery pack 20 and the front PCU 3 to a power-shared state or an off state. The front J / B 21 also performs an ON / OFF operation in accordance with a control signal from the vehicle control unit 12, thereby switching the electrical connection state between the battery pack 20 and the fast-charging port 8 to a power-shared state or an off state. A detailed configuration of the front J / B 21 is described later.

[0015] The rear J / B 22 is located on a rear side in the rear section of the front / rear part of the vehicle 1 and electrically connects the battery pack 20, the rear PCU 5, and the normal charging port 9. The rear J / B 22 performs an on / off operation in accordance with a control signal from the vehicle control unit 12, thereby switching the electrical connection state between the battery pack 20 and the rear PCU 5 to a power-distributed state or to an off state. The rear J / B 22 also performs an on / off operation in accordance with a control signal from the vehicle control unit 12, thereby switching the electrical connection state between the battery pack 20 and the normal charging port 9 to a power-distributed state or to an off state.The rear J / B 22 is formed, for example, using a contact relay (mechanical relay) or a contactless relay (semiconductor relay).

[0016] The front PCU 3 performs bidirectional electrical energy conversion between the battery pack 20 and the front motor 4 in accordance with a control signal from the vehicle control unit 12. The front PCU 3 includes an inverter 31 for driving the front motor 4 and a converter 32, which boosts a DC voltage supplied to the inverter 31 to a voltage equal to or higher than the output voltage of the battery pack 20.

[0017] The front motor 4 is formed using a rotating AC electric machine, e.g., a three-phase synchronous motor in which permanent magnets are embedded in a rotor, and serves as the drive source for the vehicle 1. The front motor 4 is driven by the front PCU 3 and generates a rotating driving force. The driving force generated by the front motor 4 is transmitted to the drive wheels 7 via a power transmission gearbox (not shown). Conversely, when the vehicle 1 is decelerating, the front motor 4 acts as an electric generator, producing regenerative energy. The electrical energy generated by the front motor 4 is fed to the battery pack 20 via the front PCU 3 and the front J / B 21 and stored in the battery pack 20.

[0018] The rear PCU 5 performs bidirectional energy conversion between the battery pack 20 and the rear motor 6 in accordance with a control signal from the vehicle control unit 12. The rear PCU 5 comprises an inverter 51 for driving the rear motor 6 and a converter 52, which boosts a DC voltage supplied to the inverter 51 to a voltage equal to or higher than the output voltage of the battery pack 20.

[0019] The rear motor 6 is formed using a rotating AC electric machine, e.g., a three-phase synchronous motor in which permanent magnets are embedded in a rotor, and serves as the drive source for the vehicle 1. The rear motor 6 is driven by the rear PCU 5 and generates a rotating motive force. The motive force generated by the rear motor 6 is transmitted to the drive wheels 7 via a power transmission gearbox (not shown). Conversely, when the vehicle 1 is decelerating, the rear motor 6 acts as an electric generator, producing regenerative energy. The electrical energy generated by the rear motor 6 is fed to the battery pack 20 via the rear PCU 5 and the rear J / B 22 and stored in the battery pack 20.

[0020] The fast charging port 8 is a so-called DC input to which a plug (not shown) of an external fast charger or an ultra-fast charger is detachably connected. The fast charging port 8 is electrically connected to the front J / B 21. The fast charging port 8 outputs the electrical power supplied to the front J / B 21 by the fast charger or the ultra-fast charger.

[0021] The standard charging port 9 is a so-called AC input, and a plug from a standard charger (not shown), which has a lower charging voltage than a fast charger, is electrically detachable from the port. The standard charging port 9 is electrically connected to the rear J / B 22. The standard charging port 9 delivers the electrical power supplied by the standard charger to the rear J / B 22.

[0022] Sensor group 10 is comprised of an accelerometer, a gyroscope, a speed sensor, an ignition sensor, etc. Sensor group 10 detects the state of vehicle 1 and outputs this detection result to the vehicle control unit 12. The state of vehicle 1 can be, for example, a stationary state, a moving state, or an idling state. If, for example, the speed sensor detects the speed of vehicle 1, sensor group 10 interprets this as driving information and outputs this detection result to the vehicle control unit 12. If the speed sensor cannot detect the speed of vehicle 1, the sensor group recognizes the state of vehicle 1 as stationary and outputs this detection result to the vehicle control unit 12.

[0023] The display unit 11 is formed using a display monitor of a liquid crystal or organic EL display (organic electroluminescent display). The display unit 11 shows various information about the vehicle 1 in accordance with control signals from the vehicle control unit 12.

[0024] The vehicle control unit 12 comprises a memory, a central processing unit (CPU), a processor with hardware, a signal input component, etc. The vehicle control unit 12 controls the units that make up the vehicle 1. Detailed configurations of the battery pack and the front J / B

[0025] Next, the detailed configurations of the battery pack 20 and the front J / B 21 in the vehicle's internal system 2 are described. Fig. Figure 2 is a diagram that schematically illustrates a detailed configuration example of the battery pack 20 and the front J / B 21 in the vehicle's internal system 2. Fig. Figure 3 is a diagram that schematically illustrates a detailed configuration example of the forward J / B 21. Detailed battery pack configuration

[0026] First, a detailed configuration of battery pack 20 is described. As in Fig. As shown in Figure 2, the battery pack 20 comprises a composite battery 201, several cell voltage monitoring units 2021 to 202 n (n = an integer that is 3 or greater) (if one of the several cell voltage monitoring units 2021 to 202 below) n (It is mentioned, it is simply referred to as the "cell voltage monitoring unit 202"), a first current sensing unit 203 and a battery ECU 204.

[0027] The composite battery 201 is attached to vehicle 1 and stores electrical energy. The composite battery 201 comprises several battery modules 20111 to 2011 n on (n = an integer that is 3 or greater) (if in the following one of the several battery modules 20111 to 2011 n When mentioned, it is simply referred to as "Battery Module 2011". The Battery Module 2011 comprises a multitude of battery cells. Each battery cell is formed using a secondary battery that can be charged and discharged. Each battery cell is formed, for example, using a lithium-ion battery or similar. The battery cells are located next to each other and are electrically connected in series with the adjacent battery cells.

[0028] The cell voltage monitoring unit 202 detects a voltage value from the battery module 2011 and is generated using a voltmeter or similar device. The cell voltage monitoring units 202 are designed to correspond to the battery modules 2011. The cell voltage monitoring units 202 are electrically connected in parallel to the battery modules 2011 and electrically connected to the battery ECU 204. The cell voltage monitoring unit 202 detects the voltage value between a positive electrode and a negative electrode of the battery module 2011 and outputs this detection result to the battery ECU 204.

[0029] The first current sensing unit 203 detects the current value in the composite battery 201, determined using an ammeter or similar device. The first current sensing unit 203 is electrically connected in series with the composite battery 201 and is electrically connected to the battery ECU 204. The first current sensing unit 203 detects the current value between a positive electrode (positive side) and a negative electrode (negative side) of the composite battery 201 and outputs this detection result to the battery ECU 204.

[0030] The battery ECU 204 monitors the voltage and current values ​​of the composite battery 201. The battery ECU 204 and the cell voltage monitoring units 202 are referred to, for example, as cell voltage sensors (CVS) or battery management system (BMS). The battery control unit 204 includes a first voltage sensing unit 204a and a first microcontroller unit (MCU) 204b.

[0031] The first voltage sensing unit 204a senses the total voltage value of the composite battery 201 and is implemented using a voltmeter or the like. The first voltage sensing unit 204a is electrically connected to a pair of electrical leads connected to the positive and negative electrodes of the composite battery 201 and is electrically connected in parallel to the composite battery 201. The first voltage sensing unit 204a senses the voltage value between the positive and negative electrodes of the composite battery 201 and outputs this sense result to the first MCU 204b. The first voltage sensing unit 204a is implemented, for example, using an analog-to-digital converter (not shown).In particular, the first voltage sensing unit 204a converts the input voltage value into a digital signal using an A / D converter and outputs the signal to the first MCU 204b. It should be noted that the position at which the first voltage sensing unit 204a is electrically connected can be modified as appropriate. For example, the first voltage sensing unit 204a can be electrically connected to a pair of electrical power lines that branch out in the front J / B 21.

[0032] The first MCU 204b, for example, comprises memory, a processor with CPU hardware, and a signal input component. The first MCU 204b receives the signals of the acquisition results acquired by the cell voltage monitoring units 202 and the first current sensing unit 203. Specifically, the first MCU 204b receives the voltage values ​​of the battery modules 2011 acquired by the cell voltage monitoring units 202. Furthermore, the first MCU 204b receives the current value between the positive and negative electrodes of the composite battery 201, acquired by the first current sensing unit 203. Additionally, the first MCU 204b is electrically connected to the first voltage sensing unit 204a and receives the voltage value of the composite battery 201 acquired by the first voltage sensing unit 204a.

[0033] Furthermore, the first MCU 204b periodically performs a self-diagnosis of the cell voltage monitoring units 202, the first voltage sensing unit 204a, and the battery ECU 204 in accordance with control signals from the vehicle control unit 12. During this self-diagnosis, the operation of each of the cell voltage monitoring units 202 and the first voltage sensing unit 204a is checked, for example. Detailed configuration of the front J / B

[0034] The following is a detailed configuration description of the forward J / B 21. As in Fig. 2 and Fig. As shown in Figure 3, the front J / B 21 is provided on the power lines that are electrically connected to the positive and negative electrodes of the composite battery 201. The front J / B 21 is equipped with a main relay unit 211, a charging relay unit 212, a second voltage sensing unit 213, a third voltage sensing unit 214, a second current sensing unit 215, a third current sensing unit 216, and a second MCU 217.

[0035] The main relay unit 211 switches the connection state between the composite battery 201 and the front PCU 3 to a power-distributed state or a power-off state in accordance with a control signal from the second MCU 217. The main relay unit 211 comprises a first main relay 211a and a second main relay 211b. It should be noted that in the first embodiment, the main relay unit 211 functions as the first relay unit.

[0036] The first main relay 211a has a first end and a second end, the first end being electrically connected to the positive electrode (positive side) of the battery pack 20, and the second end being electrically connected to the positive electrode side (positive electrode side of the inverter) of the front PCU 3. The first main relay 211a is formed using a contact relay or the like. The first main relay 211a enables or interrupts the distribution of current from the battery pack 20 in accordance with a control signal from the second MCU 217.

[0037] The second main relay 211b has a first end and a second end, the first end being electrically connected to the negative electrode (minus side) of the battery pack 20, and the second end being electrically connected to the negative electrode side (negative electrode side of the inverter 31) of the front PCU 3. The second main relay 211b is formed using a contact relay or the like. The second main relay 211b enables or interrupts the distribution of current from the battery pack 20 in accordance with a control signal from the second MCU 217.

[0038] The charging relay unit 212 switches the connection state between the composite battery 201 and the fast-charging port 8 to a power-distributed state or to a switched-off state in accordance with a control signal from the second MCU 217. The charging relay unit 212 comprises a first charging relay 212a and a second charging relay 212b. It should be noted that in the first embodiment, the charging relay unit 212 functions as a second relay unit.

[0039] The first charging relay 212a has a first end and a second end, the first end being electrically connected to the positive electrode (positive side) of the battery pack 20, and the second end being electrically connected to the positive electrode side (positive side) of a charger (e.g., the fast-charging port 8). The first charging relay 212a is formed using a contact relay or the like. The first charging relay 212a enables or interrupts the distribution of current from the battery pack 20 in accordance with a control signal from the second MCU 217.

[0040] The second charging relay 212b has a first end and a second end, the first end being electrically connected to the negative electrode (negative side) of the battery pack 20, and the second end being electrically connected to the negative electrode side (minus side) of a charger (e.g., the fast-charging port 8). The second charging relay 212b is formed using a contact relay or the like. The second charging relay 212b enables or interrupts the distribution of current from the battery pack 20 in accordance with a control signal from the second MCU 217.

[0041] The second voltage sensing unit 213 senses the voltage value of the battery pack 20 and is implemented using a voltmeter or the like. The second voltage sensing unit 213 is electrically connected between the pair of electrical power leads that connect the battery pack 20 and the front PCU 3, and is electrically connected in parallel with the assembled battery 201. The second voltage sensing unit 213 is also electrically connected to the second MCU 217. The second voltage sensing unit 213 senses the voltage value between the positive and negative electrodes of the battery pack 20 and outputs this sense result to the second MCU 217. The second voltage sensing unit 213 is implemented, for example, using an analog-to-digital converter (not shown).In particular, the second voltage sensing unit 213 converts the input voltage value into a digital signal using an A / D converter and outputs the signal to the second MCU 217.

[0042] The third voltage sensing unit 214 detects the voltage value of the battery pack 20 and is implemented using a voltmeter or the like. The third voltage sensing unit 214 is electrically connected between the pair of electrical power leads that connect the battery pack 20 and the charger, and is electrically connected in parallel with the assembled battery 201. The third voltage sensing unit 214 is also electrically connected to the second MCU 217. The third voltage sensing unit 214 detects the voltage value between the positive and negative electrodes of the battery pack 20 and outputs this detection result to the second MCU 217. The third voltage sensing unit 214 is implemented, for example, using an analog-to-digital converter (not shown).In particular, the third voltage sensing unit 214 converts the input voltage value into a digital signal using an A / D converter and outputs the signal to the second MCU 217.

[0043] The second current sensing unit 215 detects the current value in the battery pack 20 and is implemented using an ammeter or the like. The second current sensing unit 215 is electrically connected in series with the battery pack 201 and is electrically connected to the second MCU 217. Specifically, the second current sensing unit 215 is located between the electrical power lines of the second main relay 211b and the front PCU 3 (negative electrode side of the inverter 31). The second current sensing unit 215 detects the current value between the positive and negative electrodes of the battery pack 201 and outputs this detection result to the second MCU 217.

[0044] The third current sensing unit 216 detects the current value in the battery pack 20 and is implemented using an ammeter or the like. The third current sensing unit 216 is electrically connected in series with the composite battery 201 and is electrically connected to the second MCU 217. Specifically, the third current sensing unit 216 is located between the power lines of the second charging relay 212b and the charger (negative electrode side). The third current sensing unit 216 detects the current value between the positive and negative electrodes of the composite battery 201 and outputs this detection result to the second MCU 217.

[0045] The second MCU 217 includes, for example, a memory, a processor with CPU hardware, and a signal input component. The second MCU 217 controls the switching on / off operations of the main relay unit 211 and the charging relay unit 212 in accordance with control signals from a vehicle-internal output 112. Furthermore, the second MCU 217 receives the signals of the measurement results acquired by the second voltage sensing unit 213, the third voltage sensing unit 214, the second current sensing unit 215, and the third current sensing unit 216 during the switching on / off operations of the main relay unit 211 and the charging relay unit 212. In addition, the second MCU 217 monitors respective defects of the main relay unit 211, the charging relay unit 212, the second voltage sensing unit 213, the third voltage sensing unit 214 and the first voltage sensing unit 204a in accordance with the control signals from the vehicle control unit 12.In particular, when the main relay unit 211 and the charging relay unit 212 are subjected to on / off switching operations, the second MCU 217 monitors for faults in each of the units that make up the vehicle's internal system 2, based on the detection results received from the second voltage detection unit 213, the third voltage detection unit 214, the second current detection unit 215, and the third current detection unit 216, and based on the signals from the first MCU 204b. For example, when a stop signal, meaning that the vehicle 1 is stationary, is received from the vehicle control unit 12, the second MCU 217 monitors for faults in each of the units that make up the vehicle's internal system 2, in particular the main relay unit 211, the second voltage detection unit 213, and the third voltage detection unit 214.The signals from the first MCU 204b include the voltage value of the composite battery 201, as detected by a first voltage sensing unit 214a, and the current value from the first current sensing unit 203. It should be noted that in the first embodiment, the second MCU 217 functions as a control unit for the vehicle's internal system 2. Operational example of the vehicle's internal system

[0046] Next, an operational example of the vehicle's internal system 2 will be described. Fig. Figure 4 is a flowchart that represents an operational example executed by the vehicle's internal system 2.

[0047] As in Fig. As shown in Figure 4, the second MCU 217 first determines, based on the signal input from the vehicle control unit 12, whether the vehicle 1 is stationary or not (step S101). Specifically, the second MCU 217 determines whether the stop signal, which indicates that the vehicle 1 is stationary, has been received from the vehicle control unit 12. If the stop signal has been received, the second MCU 217 determines that the vehicle 1 is stationary. If the stop signal has not been received, the second MCU 217 determines that the vehicle 1 is not stationary. Here, "stationary" means one of the following states: a state in which a power source of the vehicle 1 is activated (a state in which the activation of the vehicle 1 has been detected by an ignition sensor), a state in which a door (or...The procedure is performed when the doors of vehicle 1 are unlocked, and when the main relay unit 211 undergoes a switching operation to charge a low-voltage battery using battery pack 20 as the capacity of the low-voltage battery (not shown) decreases, in a state where vehicle 1 is stationary. If the second MCU 217 determines that vehicle 1 is stationary (step S101: Yes), the procedure proceeds to step S102, described later. Conversely, if the second MCU 217 determines that vehicle 1 is not stationary (step S101: No), the present procedure terminates.

[0048] In step S102, the second MCU 217 performs a defect detection procedure on each of the units that make up the vehicle's internal system 2. After step S102, the second MCU 217 proceeds to step S103, which is described later. This step details the defect detection procedure. Fig. Figure 5 is a diagram that illustrates an example of the contents of the defect determination procedure performed by the second MCU 217.

[0049] First, in the Fig. Table T1, shown in Figure 5, describes a case in which the second MCU 217 performs a check element “front J / B 21, main relay check 1” while the vehicle 1 is stationary.

[0050] First, the second MCU 217 interrupts the power-shared state between the composite battery 201 and the front J / B 21 by switching off the first main relay 211a and the second main relay 211b. Furthermore, the second MCU 217 interrupts the power-shared state between the composite battery 201 and the fast-charging port 8 by switching off the first charging relay 212a and the second charging relay 212b. In this case, the second MCU 217 obtains the voltage value detected by the second voltage sensing unit 213 (main-side voltage sensor) and determines whether the obtained voltage value is not 0 (front J / B 21 main-side voltage sensor ≠ 0). Specifically, the second MCU 217 determines whether the voltage of the composite battery 201 is applied to the front J / B 21.If the voltage value obtained from the second voltage sensing unit 213 (main-side voltage sensor) is 0, the second MCU 217 determines that neither the first main relay 211a nor the second main relay 211b is short-circuited. In other words, the second MCU 217 determines that both the first main relay 211a and the second main relay 211b are functioning normally. Conversely, if the voltage value obtained from the second voltage sensing unit 213 (main-side voltage sensor) is not 0, the second MCU 217 determines that both the first main relay 211a and the second main relay 211b are short-circuited. In other words, the second MCU 217 determines that both the first main relay 211a and the second main relay 211b are defective.

[0051] As in the Fig. As illustrated in Table T1 shown in Figure 5, the second MCU 217 performs a verification element “front J / B 21 main relay check 2, 3” by a procedure similar to the “front J / B 21, main relay check 1” described above, while the vehicle 1 is stationary.

[0052] Next, in the Fig. Table T1, shown in Figure 5, describes a case in which the second MCU 217 performs a check element “front J / B 21, main relay check 4” while the vehicle 1 is stationary.

[0053] First, the second MCU 217, by energizing the first main relay 211a and the second main relay 211b, causes the combined battery 201 and the front J / B 21 to be in a power-distributed state. In this case, the second MCU 217 obtains the voltage value detected by the second voltage sensing unit 213 (main-side voltage sensor) and the voltage value detected by the first voltage sensing unit 204a from the first MCU 204b. The second MCU 217 then determines whether the voltage value detected by the second voltage sensing unit 213 (main-side voltage sensor) and the voltage value detected by the first voltage sensing unit 204a are equal or not (J / B main-side voltage sensor = battery ECU voltage sensor).If the voltage value detected by the second voltage sensing unit 213 (main-side voltage sensor) and the voltage value detected by the first voltage sensing unit 204a are the same, the second MCU 217 determines that the main relay unit 211 is functioning normally. In other words, the second MCU 217 can determine that the main relay unit 211 should be switched on. If, on the other hand, the voltage value detected by the second voltage sensing unit 213 (main-side voltage sensor) and the voltage value detected by the first voltage sensing unit 204a do not match, the second MCU 217 determines that the main relay unit 211 is faulty. In other words, the second MCU 217 determines that the main relay unit 211 cannot be switched on.

[0054] As in the Fig. As illustrated in Table T1, the second MCU 217 also performs the test elements "Charging Relay Check 1 to 4" in the charging relay unit 212 using a procedure similar to that described above for the main relay unit 211. Specifically, the second MCU 217 subjects the first charging relay 212a and the second charging relay 212b to on / off cycles. In this case, the second MCU 217 obtains the voltage value detected by the third voltage sensing unit 214 (J / B-side voltage sensor) and the voltage value detected by the first voltage sensing unit 204a from the first MCU 204b. Subsequently, the second MCU 217 monitors for defects in each unit of the charging relay unit 212 based on the voltage value obtained from the third voltage sensing unit 214 (J / B-side voltage sensor) and the voltage value obtained from the first voltage sensing unit 204a.

[0055] Furthermore, the second MCU 217, as in the Fig. Table T1, shown in Figure 5, illustrates that the test elements “front J / B 21 main relay-side voltage sensor check” and “front J / B 21 charging relay-side voltage sensor check” are performed using a similar procedure to that described above for the main relay unit 211. Specifically, the second MCU 217 obtains a voltage reading from the second voltage sensing unit 213, the third voltage sensing unit 214, and the first voltage sensing unit 204a when the main relay unit 211 and the charging relay unit 212 are subjected to on / off cycles. Subsequently, the second MCU 217 monitors for defects in the second voltage sensing unit 213 and the third voltage sensing unit 214 based on the voltage readings obtained from these units.

[0056] As in the Fig. As illustrated in Table T1, the second MCU 217 performs a test element, "Battery ECU Battery Voltage Sensor Check," using a procedure similar to that described above for the main relay unit 211. Specifically, the second MCU 217 obtains voltage readings from the second voltage sensing unit 213, the third voltage sensing unit 214, and the first voltage sensing unit 204a when the main relay unit 211 and the charging relay unit 212 are subjected to on / off cycles. Subsequently, the second MCU 217 monitors for faults in the first voltage sensing unit 204a based on battery readings obtained from the second voltage sensing unit 213, the third voltage sensing unit 214, and the first voltage sensing unit 204a.

[0057] In this way, the second MCU 217 monitors defects of each of the units of the vehicle's internal system 2, based on the voltage values ​​from the second voltage sensing unit 213, the third voltage sensing unit 214 and the first voltage sensing unit 204a, when the main relay unit 211 and the charging relay unit 212 are subjected to on / off switching operations.

[0058] Referring again to Fig. 4, the description of step S103 and subsequent steps continues.

[0059] In step S103, if one of the units comprising the vehicle's internal system 2 is defective (step S103: Yes), the second MCU 217 issues a warning via display unit 11 and vehicle control unit 12 indicating that one of the units comprising the vehicle's internal system 2 is defective (step S104). In this case, in addition to the output to display unit 11, the second MCU 217 can also cause a speaker (not shown) or similar device via vehicle control unit 12 to issue a warning indicating that one of the units comprising the vehicle's internal system 2 is defective. This allows a user of vehicle 1 to intuitively understand the occurrence of the defect in the vehicle's internal system 2 installed in vehicle 1. After step S104, the second MCU 217 terminates the current procedure.If, however, none of the units comprising the vehicle's internal system 2 has a defect (step S103: No), the second MCU 217 terminates the present procedure.

[0060] Based on the configuration described above, the second MCU 217 in the vehicle's internal system 2 monitors whether the main relay unit 211, the first voltage sensing unit 204a, and the second voltage sensing unit 213 each exhibit anomalies. This is done based on the sensing results acquired by the first voltage sensing unit 204a and the second voltage sensing unit 213 when the main relay unit 211 undergoes on / off cycles. This allows for the differentiation and detection of defects in the first voltage sensing unit 204a (voltage sensor) of the battery ECU 204 and the main relay unit 211 in the front J / B 21. This enables the detection of relay defects, such as those of a mechanical or semiconductor type.

[0061] Based on the data acquired by the first voltage sensing unit 204a and the third voltage sensing unit 214 when the charging relay unit 212 is subjected to on / off cycles, the second MCU 217 in the vehicle-internal system 2 described above monitors whether the charging relay unit 212, the first voltage sensing unit 204a, and the third voltage sensing unit 214 are defective. This allows defects in the first voltage sensing unit 204a (voltage sensor) of the battery ECU 204 and the charging relay unit 212 in the front J / B 21 to be distinguished and detected.

[0062] In the vehicle-internal system 2 described above, the second MCU 217 monitors whether the main relay unit 211, the first voltage sensing unit 204a, and the second voltage sensing unit 213 each exhibit an anomaly, based on the sensing results acquired by the first voltage sensing unit 204a and the second voltage sensing unit 213 when the main relay unit 211 is subjected to on / off cycles while the vehicle is stationary. Furthermore, the second MCU 217 monitors whether the charging relay unit 212, the first voltage sensing unit 204a, and the third voltage sensing unit 214 each exhibit defects, based on the sensing results acquired by the first voltage sensing unit 204a and the third voltage sensing unit 214 when the charging relay unit 212 is subjected to on / off cycles.In this way, defects in the units that make up the vehicle's internal system 2 can be detected before the vehicle 1 is put into motion.

[0063] The second MCU 217 issues a warning to the display unit 11 in the vehicle's internal system 2 described above if at least one of the following units is defective: the main relay unit 211, the charging relay unit 212, the first voltage sensing unit 204a, the second voltage sensing unit 213, and the third voltage sensing unit 214, with the warning indicating the occurrence of the defect. This allows a user of vehicle 1 to intuitively understand the occurrence of the defect in the vehicle's internal system 2 installed in vehicle 1.

[0064] It should be noted that in the vehicle-internal system 2 described above, the second voltage sensing unit 213, the third voltage sensing unit 214, the second current sensing unit 215, and the third current sensing unit 216 are provided in the front J / B 21, but are not limited to this location. The second voltage sensing unit 213, the third voltage sensing unit 214, the second current sensing unit 215, and the third current sensing unit 216 can also be provided in the rear J / B 22. In this way, defects in the first voltage sensing unit 204a (voltage sensor) of the battery ECU 204 and the relay of each of the individual units in the rear J / B 22 can be differentiated and detected. Second embodiment

[0065] Next, an in-vehicle system according to a second embodiment is described. The in-vehicle system according to the second embodiment is further equipped with a rear J / B sensor capable of detecting voltage and current values ​​at the rear of a battery pack. Furthermore, the in-vehicle system according to the second embodiment can detect the current value of the battery pack even if either the current sensor on the front side of the J / B sensor or the current sensor on the rear side of the J / B sensor is defective. A vehicle according to the second embodiment is described below. It should be noted that in the second embodiment, certain elements corresponding to those of the first embodiment are identified with the same symbols, and a detailed description of these elements is omitted. Vehicle configuration

[0066] Fig. Figure 6 is a diagram that briefly illustrates a configuration of a vehicle to which the in-vehicle system is attached according to the second embodiment.

[0067] A in Fig. The vehicle 1A shown in Figure 6 is equipped with an internal system 2A instead of the internal system 2 of vehicle 1 according to the first embodiment. The internal system 2A is attached to vehicle 1A as the vehicle 1A's energy source and supplies electrical energy to load components such as the front motor 4 and the rear motor 6. The internal system 2A is equipped with a rear J / B 22A instead of the rear J / B 22 of the internal system 2 according to the first embodiment.

[0068] The rear J / B 22A is located on the rear side of the front / rear section of the vehicle 1A and electrically connects the battery pack 20, the rear PCU 5, and the normal charging port 9. The rear J / B 22A performs an on / off operation in accordance with a control signal from the vehicle control unit 12, thereby switching the electrical connection state between the battery pack 20 and the rear PCU 5 to a power-distributed state or an off state. Additionally, the rear J / B 22A performs an on / off operation in accordance with a control signal from the vehicle control unit 12, thereby switching the electrical connection state between the battery pack 20 and the normal charging port 9 to a power-distributed state or an off state. Detailed configurations of the battery pack, the front J / B and the rear J / B

[0069] Next, detailed configurations of the battery pack 20, the front J / B 21 and the rear J / B 22A in the vehicle's internal system 2A are described. Fig. Figure 7 is a diagram that schematically illustrates a detailed configuration example of the battery pack 20, the front J / B 21 and the rear J / B 22A in the vehicle's internal system 2A. Detailed configuration of the rear J / B 22

[0070] As in Fig. As shown in Figure 7, the rear J / B 22A is provided on the power lines that are electrically connected to the positive and negative electrodes of the composite battery 201. The rear J / B 22A is equipped with a main relay unit 221, a charging relay unit 222, a fourth voltage sensing unit 223, a fifth voltage sensing unit 224, a fourth current sensing unit 225, a fifth current sensing unit 226, and a third MCU 227.

[0071] The main relay unit 221 switches the electrical connection state between the composite battery 201 and the rear PCU 5 to a power-distributed state or to an off state in accordance with a control signal from the third MCU 227. The main relay unit 221 has a similar configuration to the main relay unit 211 of the front J / B 21 (see Fig. 3) and features the first main relay 211a and the second main relay 211b. Therefore, a detailed description is omitted.

[0072] The charging relay unit 222 switches the electrical connection state between the composite battery 201 and the normal charging port 9 to a power-distributed state or an off state in accordance with a control signal from the third MCU 227. The charging relay unit 222 has a similar configuration to the charging relay unit 212 of the front J / B 21 (see Fig. 3) and features the first charging relay 212a and the second charging relay 211b. Therefore, a detailed description is omitted.

[0073] The fourth voltage sensing unit 223 is electrically connected between the pair of electrical power leads that connect the battery pack 20 and the rear PCU 5, and is electrically connected in parallel with the composite battery 201. The fourth voltage sensing unit 223 is also electrically connected to the third MCU 227. The fourth voltage sensing unit 223 senses the voltage value between the positive and negative electrodes of the battery pack 20 and outputs this sense result to the third MCU 227. The fourth voltage sensing unit 223 is implemented, for example, using an analog-to-digital converter (not shown). Specifically, the fourth voltage sensing unit 223 converts the input voltage value into a digital signal using an analog-to-digital converter and outputs the signal to the third MCU 227.

[0074] The fifth voltage sensing unit 224 is electrically connected between the pair of electrical power leads that connect the battery pack 20 and the charger, and is electrically connected in parallel with the assembled battery 201. The fifth voltage sensing unit 224 is also electrically connected to the third MCU 227. The fifth voltage sensing unit 224 senses the voltage value between the positive and negative electrodes of the battery pack 20 and outputs this sense result to the third MCU 227. The fifth voltage sensing unit 224 is implemented, for example, using an analog-to-digital converter (ADC) (not shown). Specifically, the fifth voltage sensing unit 224 converts the input voltage value into a digital signal using an ADC and outputs the signal to the third MCU 227.

[0075] The fourth current sensing unit 225 detects the current value in the battery pack 20. The fourth current sensing unit 225 is electrically connected in series with the composite battery 201 and is electrically connected to the third MCU 227. Specifically, the fourth current sensing unit 225 is located between the power lines of the second main relay 211b and the front PCU 3 (negative electrode side of the inverter 31). The fourth current sensing unit 225 detects the current value between the positive and negative electrodes of the composite battery 201 and outputs this detection result to the third MCU 227.

[0076] The fifth current sensing unit 226 detects the current value in the battery pack 20. The fifth current sensing unit 226 is electrically connected in series with the composite battery 201 and is electrically connected to the third MCU 227. Specifically, the fifth current sensing unit 226 is located between the power lines of the second charging relay 212b and the charger (negative electrode side). The fifth current sensing unit 226 detects the current value between the positive and negative electrodes of the composite battery 201 and outputs this detection result to the third MCU 227.

[0077] The third MCU 227, for example, includes memory, a processor with CPU hardware, and a signal input component. The third MCU 227 receives the signals of the measurement results acquired by the fourth voltage sensing unit 223, the fifth voltage sensing unit 224, the fourth current sensing unit 225, and the fifth current sensing unit 226. Furthermore, the third MCU 227 monitors for any respective faults in the main relay unit 221, the charging relay unit 222, the fourth voltage sensing unit 223, the fifth voltage sensing unit 224, and the first voltage sensing unit 204a, in accordance with the control signals from the vehicle control unit 12.

[0078] The vehicle-internal system 2A formed in this way monitors defects in each of the units that make up the vehicle-internal system 2A, while the vehicle 1A remains stationary in accordance with the control signals from the vehicle control unit 12, and the first MCU 204b, the second MCU 217, and the third MCU 227 work together in a coordinated manner. In other words, the first MCU 204b, the second MCU 217, and the third MCU 227 perform the operations similarly to those in Fig. 4 out, while they work together in a coordinated manner.

[0079] Fig. Figure 8 is a diagram showing an example of the contents of a defect detection process performed by the vehicle's in-vehicle system 2A according to the second embodiment. As shown in Table T2 of Fig.As shown in Figure 8, a defect in each of the units comprising the vehicle's internal system 2A is monitored while the vehicle 1A is stationary in accordance with the control signals from the vehicle control unit 12, and the first MCU 204b, the second MCU 217, and the third MCU 227 work together in a coordinated manner. It should be noted that in the second embodiment, a defect in each of the units comprising the vehicle's internal system 2A can be monitored while the vehicle 1A is stationary, with either the first MCU 204b, the second MCU 217, or the third MCU 227 acting as the master unit and the remaining units acting as slave units to work together in a coordinated manner.

[0080] Furthermore, the vehicle-internal system 2A can also calculate the current value of the battery pack 20 even if the first current sensing unit 203, the second current sensing unit 215, the third current sensing unit 216, the fourth current sensing unit 225 or the fifth current sensing unit 226 fails, by using the first current sensing unit 203 in battery pack 20, the second current sensing unit 215 and the third current sensing unit 216 in the front J / B 21 and the fourth current sensing unit 225 and the fifth current sensing unit 226 of the rear J / B 22A. In particular, if the second current sensing unit 215 of the front J / B 21 fails, the vehicle's internal system 2A can calculate the current value of the current of the front J / B 21 by subtracting the current value detected by the fourth current sensing unit 225 of the rear J / B 22A from the current value detected by the first current sensing unit 203.

[0081] Due to the configuration described above, the front J / B 21 is located at the front of the battery pack 20 and the rear J / B 22A at the rear; therefore, the vehicle's internal system 2A can distinguish and detect a fault in the first voltage sensing unit 204a (voltage sensor) of the battery ECU 204, the main relay unit 211 in the front J / B 21, and the main relay unit 221 in the rear J / B 22A. In this way, the vehicle's internal system 2A can perform redundant detection by using the sensors that make up the vehicle's internal system 2A and the relays as a single system. Therefore, since the vehicle's internal system 2A is redundant, the vehicle 1A can continue to drive even if the first voltage sensing unit 204a (voltage sensor) of the battery ECU 204, the main relay unit 211 in the front J / B 21 or the main relay unit 221 in the rear J / B 22A fails.

[0082] Since the second MCU 217 uses the acquisition results of the first current acquisition unit 203, the second current acquisition unit 215, the third current acquisition unit 216, the fourth current acquisition unit 225 and the fifth current acquisition unit 226, the vehicle-internal system 2A described above can calculate the current value of the battery pack 20 even if the first current acquisition unit 203, the second current acquisition unit 215, the third current acquisition unit 216, the fourth current acquisition unit 225 or the fifth current acquisition unit 226 fails. Other embodiments

[0083] In the first and second embodiments, the "units" described above can be replaced, for example, by "circuits". Thus, the vehicle control unit can be replaced by a vehicle control circuit.

[0084] In the explanation of the flowchart in this description, the context of the sequence of steps is indicated by the use of expressions such as "first," "then," "subsequently," or the like. However, the sequences of the process required to enable the embodiment are not uniquely specified by these expressions. In other words, the sequence of the process in the flowchart described in this description can be modified within a range without contradiction.

[0085] The vehicle-internal system according to the present embodiments is able to distinguish and detect defects of the voltage sensor and the relay in the junction box.

Claims

[1] In-vehicle system (2) which includes the following: a junction box (21, 22) arranged on the front and / or rear of a battery pack (20) provided in an electric vehicle (1); and a first voltage sensing unit (204a) that detects a voltage value of the battery pack (20), wherein the junction box (21, 22) has the following features: a first relay unit (211, 221) which is electrically connected to the battery pack (20) and a drive source (4, 6) and switches the state of the battery pack (20) and the drive source (4, 6) into an energy-distributed state or a switched-off state by means of an on / off operation, a second voltage sensing unit (213, 223) which is electrically connected in parallel to the battery pack (20) and detects a voltage value of the battery pack (20), and a controller (217, 227) configured to control the on / off switching operation of the first relay unit (211, 221), and wherein the controller (217, 227) monitors whether the first relay unit (211, 221), the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223) each exhibit an anomaly or not, based on a sensing result that is each detected by the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223) when the first relay unit (211, 221) performs the on / off operation. [2] Vehicle-internal system (2) according to claim 1, wherein the connection box (21, 22) further comprises: a second relay unit (212, 222) which is electrically connected to the battery pack (20) and a charging port (8, 9) and switches the state of the battery pack (20) and the charging port (8, 9) into an energy-distributed state or an off state by means of an on / off switching operation, wherein the charging port (8, 9) is supplied with electrical energy from the outside, and a third voltage sensing unit (214, 224) which is electrically connected in parallel to the battery pack (20) and detects a voltage value of the battery pack (20), and wherein the controller (217, 227) monitors whether the second relay unit (212, 222), the first voltage sensing unit (204a) and the third voltage sensing unit (214, 224) each exhibit an anomaly or not, based on a sensing result that is each detected by the first voltage sensing unit (204a) and the third voltage sensing unit (214, 224) when the second relay unit (212, 222) performs the on / off switching operation. [3] Vehicle-internal system (2) according to claim 2, wherein the control (217, 227) the first relay unit (211, 221) and the second relay unit (212, 222) are subjected to the on / off switching operations while the electric vehicle (1) is stationary, monitors whether the first relay unit (211, 221), the first voltage sensing unit (204a), or the second voltage sensing unit (213, 223) is defective or not, based on a sensing result acquired by the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223), respectively, when the first relay unit (211, 221) is subjected to the on / off switching operation, and monitors whether the second relay unit (212, 222), the first voltage sensing unit (204a) or the third voltage sensing unit (214, 224) has a defect or not, based on a sensing result that is respectively acquired by the first voltage sensing unit (204a) and the third voltage sensing unit (214, 224) when the second relay unit (212, 222) is subjected to the on / off switching operation. [4] In-vehicle system (2) according to claim 3, wherein the controller (217, 227) issues a warning to a display (11) provided in the electric vehicle (1) when at least one of the following units has a defect: the first relay unit (211, 221), the second relay unit (212, 222), the first voltage sensing unit (204a), the second voltage sensing unit (213, 223), and the third voltage sensing unit (214, 224), wherein the issued warning indicates the occurrence of the defect. [5] Vehicle-internal system (2) according to any one of claims 1 to 4, further comprising: a first current sensing unit (203) that senses a current value of the battery pack (20); wherein the junction box (21, 22) further comprises a second current sensing unit (213, 214, 225, 227) which is electrically connected between the drive source (4, 6) and the first relay unit (211, 221) and which detects the current value of the battery pack (20), and wherein the controller (217, 227) monitors the current value of the battery pack (20) based on the current value detected by the first current sensing unit (203) and the second current sensing unit (213, 214, 225, 227), respectively. [6] Junction box (21, 22) arranged on the front and / or rear of a battery pack (20), wherein the battery pack (20) is provided in an electric vehicle (1) and has a first voltage sensing unit (204a) capable of sensing a voltage value, wherein the junction box (21, 22) comprises: a first relay unit (211, 221) which is electrically connected to the battery pack (20) and a drive source (4, 6) and switches the state of the battery pack (20) and the drive source (4, 6) into an energy-distributed state or a switched-off state by means of an on / off operation; a second voltage sensing unit (213, 223) which is electrically connected in parallel to the battery pack (20) and detects a voltage value of the battery pack (20); and a controller (217, 227) configured to control the on / off operation of the first relay unit (211, 221), wherein the controller (217, 227) monitors whether the first relay unit (211, 221), the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223) each exhibit an anomaly or not, based on a sensing result that is each detected by the first voltage sensing unit (204a) and the second voltage sensing unit (213, 223) when the first relay unit (211, 221) performs the on / off operation.

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