Vehicle cut-off control device

Abstract

The present invention can detect a charging overcurrent from a charging unit and a discharging overcurrent through the charging unit with a simple configuration, and can effectively prevent these overcurrent. A vehicle cut-off control device (40) is provided with: a first cut-off unit (41) that switches from a first release state in which a second common path (12A) is cut off, to a first cut-off state in which the first cut-off state is released; a second cut-off unit (42) that switches from a second release state in which the second branch path (12B) is cut off to a second cut-off state in which the second cut-off state is released; a first detection unit (71) that detects the current value flowing through the second common path (12A) and the direction in which the current flows; a second detection unit (72) that detects that a current flows to the second branch; and a control unit (50) that, on the basis of detection signals detected by the first detection unit (71) and the second detection unit (72), switches the first cutoff unit (41) from the first release state to the first cutoff state, and switches the second cutoff unit (42) from the second release state to the second cutoff state.

Description

Technical Field

[0001] The present disclosure relates to a cut-off control device for a vehicle. Background Art

[0002] In an energization control system for an electric vehicle, in the case of an abnormality such as when an impact is applied to the vehicle or a load short circuit occurs, a mechanism for cutting off the conduction path between a storage battery and a load (inverter, DCDC converter, charger, etc.) is used. For example, a structure that uses a physical cut-off mechanism such as a contactor or a fuse to cut off the conduction path can be cited.

[0003] In recent years, against the background of high output and rapid charging of storage batteries, the low impedance of storage batteries has been promoted, and further promotion of low impedance is considered. Regarding the increase in short-circuit current caused by low impedance and the increase in the rate of increase of short-circuit current, a large short-circuit withstand capacity is required including peripheral circuits, resulting in high costs in the conventional structure using a physical cut-off mechanism.

[0004] Therefore, a cut-off device for cutting off short-circuit current is considered, and the conduction path between the storage battery and the load is cut off by electrical insulation. For example, in the vehicle power cut-off system disclosed in Patent Document 1, a pyrotechnic circuit breaker is provided in the path between the power storage unit and the load, and the path is cut off by the pyrotechnic circuit breaker in the case of an abnormality.

[0005] Prior Art Documents Patent Documents Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-13791 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the case of a structure in which a power storage unit that supplies power to a load is supplied with power from a charging unit, in order to protect the wiring from overcharging current from the charging unit and over-discharging current from the power storage unit, it is possible to consider providing a pyrotechnic circuit breaker as in Patent Document 1 in the path commonly used during charging and discharging. Then, an abnormal state is determined based on the current value of the path commonly used during charging and discharging, and the pyrotechnic circuit breaker is cut off. In such a structure, it is difficult to distinguish between overcharging current from the charging unit, over-discharging current via the charging unit, and over-discharging current via the load, and only the cut-off of the path commonly used during charging and discharging becomes a protection operation.

[0008] The present disclosure has been completed based on the above circumstances, and an object thereof is to provide a technique capable of detecting overcharging current from a charging unit and over-discharging current via the charging unit with a simple structure and effectively blocking these overcurrents.

[0009] Technical Means for Solving the Problems

[0010] The vehicle cut-off control device of the present disclosure is used in a vehicle power supply system, which includes: a power storage unit charged by a charging unit; and a load supplied with power from the power storage unit. Among them, The in-vehicle power supply system includes: a first conductive path provided between the high-potential side terminal of the power storage unit and the high-potential side terminal of the load; a second conductive path provided between the low-potential side terminal of the power storage unit and the low-potential side terminal of the load; a first branch path branched from the first conductive path and provided between the first conductive path and the high-potential side terminal of the charging unit; and a second branch path branched from the second conductive path and provided between the second conductive path and the low-potential side terminal of the charging unit, The first conductive path has: a first common path provided between the power storage unit and the first branch path; and a third branch path provided between the first branch path and the load, The second conductive path has: a second common path provided between the power storage unit and the second branch path; and a fourth branch path provided between the second branch path and the load, The vehicle cut-off control device includes: A first cut-off unit that switches from a first release state to a first cut-off state, where the first cut-off state is a state in which at least one of the first common path and the second common path is cut off, and the first release state is a state in which the first cut-off state is released; A second cut-off unit that switches from a second release state to a second cut-off state, where the second cut-off state is a state in which at least one of the first branch path and the second branch path is cut off, and the second release state is a state in which the second cut-off state is released; A first detection unit that detects the current value flowing through at least one of the first common path and the second common path and the direction of current flow; A second detection unit that detects the situation where current flows into at least one of the first branch path and the second branch path; and A control unit that, based on the detection signals detected by the first detection unit and the second detection unit, causes the first cut-off unit to switch from the first release state to the first cut-off state and causes the second cut-off unit to switch from the second release state to the second cut-off state.

[0011] Advantages of the Invention

[0012] The technology related to the present disclosure can detect charging overcurrent from the charging unit and discharging overcurrent via the charging unit with a simple structure, and can efficiently prevent these overcurrents. Description of the Drawings

[0013] Figure 1 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to the first embodiment. Figure 2 is a flowchart illustrating the control flow performed by the control unit of the vehicle cut-off control device. Figure 3 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to the second embodiment. Figure 4 is a schematic explanation Figure 3 of the internal structure of the control unit. Figure 5 is a flowchart illustrating the control flow performed by the control unit of the vehicle cut-off control device. Figure 6 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to other embodiments. Figure 7 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to other embodiments. Figure 8 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to other embodiments. Figure 9 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to other embodiments. Figure 10 is a block diagram schematically illustrating a vehicle power supply system including a vehicle cut-off control device according to other embodiments. Detailed Embodiments

[0014] 〔1〕A vehicle cut-off control device used in a vehicle power supply system, the vehicle power supply system including: a power storage unit charged by a charging unit; and a load supplied with power from the power storage unit, wherein the vehicle power supply system includes: a first conductive path provided between a high-potential side terminal of the power storage unit and a high-potential side terminal of the load; a second conductive path provided between a low-potential side terminal of the power storage unit and a low-potential side terminal of the load; a first branch path branched from the first conductive path and provided between the first conductive path and a high-potential side terminal of the charging unit; and a second branch path branched from the second conductive path and provided between the second conductive path and a low-potential side terminal of the charging unit, the first conductive path has: a first common path provided between the power storage unit and the first branch path; and a third branch path provided between the first branch path and the load, The second conduction path has: a second common path provided between the power storage unit and the second branch path; and a fourth branch path provided between the second branch path and the load. The vehicle cut-off control device includes: a first cut-off unit that switches from a first release state to a first cut-off state, the first cut-off state being a state in which at least one of the first common path and the second common path is cut off, and the first release state being a state in which the first cut-off state is released; a second cut-off unit that switches from a second release state to a second cut-off state, the second cut-off state being a state in which at least one of the first branch path and the second branch path is cut off, and the second release state being a state in which the second cut-off state is released; a first detection unit that detects a current value and a direction of current flow through at least one of the first common path and the second common path; a second detection unit that detects a situation where current flows into at least one of the first branch path and the second branch path; and a control unit that, based on detection signals detected by the first detection unit and the second detection unit, causes the first cut-off unit to switch from the first release state to the first cut-off state and causes the second cut-off unit to switch from the second release state to the second cut-off state.

[0015] In the vehicle cut-off control device of the above [1], by the first detection unit detecting a current having a relatively large current value flowing in the flow from the high-potential side terminal of the charging unit toward the low-potential side terminal, it is possible to detect a state in which a charging overcurrent flows from the charging unit. Further, by the first detection unit detecting a current having a relatively large current value flowing in the flow from the low-potential side terminal of the charging unit toward the high-potential side terminal, and the second detection unit detecting a situation where current flows into at least one of the first branch path and the second branch path, it is possible to detect a state in which a discharge overcurrent flows via the charging unit. Detection of these states can be achieved by a simple structure provided with the first detection unit and the second detection unit. Moreover, by the control of cutting off between the power storage unit and the charging unit and the load using the cut-off of the first cut-off unit, and the control of cutting off between the power storage unit and the charging unit using the cut-off of the second cut-off unit, it is possible to effectively prevent these detected overcurrent states.

[0016] 〔2〕In the vehicle cut-off control device described in 〔1〕, it has the following characteristics. In at least one of the first common path and the second common path, the direction of the charging current flowing from the high-potential side terminal of the charging unit toward the low-potential side terminal is set as the first direction. When the current value detected by the first detection unit is in an increasing state and the direction of the current flowing detected by the first detection unit is the first direction, the control unit sets the first cut-off unit to the first released state and controls the second cut-off unit to the second cut-off state.

[0017] In the vehicle cut-off control device of the above 〔2〕, when the current value detected by the first detection unit is in an increasing state and the direction of the current flowing detected by the first detection unit is the first direction (the direction of the normal charging current during charging by the charging unit), it is assumed that a charging overcurrent flows from the charging unit. In such a case, by cutting off at least one of the first branch path and the second branch path, the charging overcurrent from the charging unit side can be prevented, and by releasing the cut-off of at least one of the first common path and the second common path, the power supply from the power storage unit to the load can be maintained.

[0018] 〔3〕In the vehicle cut-off control device described in 〔1〕 or 〔2〕, it has the following characteristics. In at least one of the first common path and the second common path, the direction of the charging current flowing from the low-potential side terminal of the charging unit toward the high-potential side terminal is set as the second direction. When the current value detected by the first detection unit is in an increasing state, the direction of the current flowing detected by the first detection unit is the second direction, and the second detection unit detects that the current flows into at least one of the first branch path and the second branch path, the control unit sets the first cut-off unit to the first released state and controls the second cut-off unit to the second cut-off state.

[0019] In the vehicle cut-off control device of the above 〔3〕, when the current value detected by the first detection unit is in an increasing state, the direction of the current flowing detected by the first detection unit is the second direction, and the current flows into at least one of the first branch path and the second branch path, it is assumed that a discharge overcurrent flows through the charging unit. In such a case, by cutting off at least one of the first branch path and the second branch path, the discharge overcurrent from the power storage unit side to the charging unit side can be prevented, and by releasing the cut-off of at least one of the first common path and the second common path, the power supply from the power storage unit to the load can be maintained.

[0020] 〔4〕In the vehicle cut-off control device according to any one of 〔1〕 to 〔3〕, it has the following characteristics. In at least one of the first common path and the second common path, the direction of the charging current flowing from the low-potential side terminal to the high-potential side terminal of the charging unit is set as the second direction. When the current value detected by the first detection unit is in an increasing state, the direction of the current detected by the first detection unit is the second direction, and the second detection unit detects that no current flows into at least one of the first branch path and the second branch path, the control unit sets the first cut-off unit to the first cut-off state.

[0021] In the vehicle cut-off control device of 〔4〕 above, when the current value detected by the first detection unit is in an increasing state, the direction of the current detected by the first detection unit is the second direction, and no current flows into at least one of the first branch path and the second branch path, it is assumed that a discharge overcurrent flows from the power storage unit side to the load side. In such a case, by cutting off at least one of the first common path and the second common path, the discharge overcurrent from the power storage unit side to the load side can be blocked.

[0022] 〔5〕In the vehicle cut-off control device according to any one of 〔1〕 to 〔4〕, it has the following characteristics. The first detection unit is a current sensor, and the current sensor is provided on one of the first common path and the second common path and detects the current value and the direction of the flowing current of this common path.

[0023] In the vehicle cut-off control device of 〔5〕 above, the overcurrent state of one of the first common path and the second common path can be detected by a simple structure of providing a current sensor on one of the first common path and the second common path.

[0024] 〔6〕In the vehicle cut-off control device according to any one of 〔1〕 to 〔5〕, it has the following characteristics. The second detection unit is a current sensor as follows: The current sensor is provided on one of the first branch path and the second branch path or on one of the third branch path and the fourth branch path, and based on the current flowing into at least one of the first branch path and the second branch path or at least one of the third branch path and the fourth branch path, it detects the situation of current flowing into at least one of the first branch path and the second branch path.

[0025] In the vehicle cut-off control device of 〔6〕 above, the situation of current flowing into at least one of the first branch path and the second branch path can be detected by a simple structure of providing a current sensor on one of the first branch path and the second branch path or on one of the third branch path and the fourth branch path.

[0026] 〔7〕In the vehicle cut-off control device according to any one of 〔1〕 to 〔5〕, it has the following features. It includes: a semiconductor circuit breaker that is switched between a third cut-off state and a third release state by the control of the control unit, the third cut-off state being a state in which at least one of the first branch circuit and the second branch circuit is cut off, and the third release state being a state in which the third cut-off state is released; and a diode that is connected in parallel with the semiconductor circuit breaker in such a way that the anode is provided on the low-potential side terminal side of the charging unit and the cathode is provided on the high-potential side terminal side of the charging unit, the second detection unit detecting the voltage of the anode with respect to the cathode, and the control unit, when setting the semiconductor circuit breaker to the third cut-off state, determines that current flows to at least one of the first branch circuit and the second branch circuit when the voltage detected by the second detection unit is in a first high-voltage state.

[0027] In the vehicle cut-off control device of the above 〔7〕, the control unit can determine whether current flows to at least one of the first branch circuit and the second branch circuit based on the voltage detected by the second detection unit by setting the semiconductor circuit breaker to the third cut-off state. In addition, by setting the semiconductor circuit breaker to the third cut-off state, at least one of the first branch circuit and the second branch circuit can be cut off at high speed.

[0028] 〔8〕In the vehicle cut-off control device according to any one of 〔1〕 to 〔5〕, 〔7〕, it has the following features. It includes: a semiconductor circuit breaker that is switched between a third cut-off state and a third release state by the control of the control unit, the third cut-off state being a state in which at least one of the first branch circuit and the second branch circuit is cut off, and the third release state being a state in which the third cut-off state is released; and a diode that is connected in parallel with the semiconductor circuit breaker in such a way that the anode is provided on the low-potential side terminal side of the charging unit and the cathode is provided on the high-potential side terminal side of the charging unit, the second detection unit detecting the voltage of the cathode with respect to the anode, and the control unit, when setting the semiconductor circuit breaker to the third cut-off state, determines that current does not flow to at least one of the first branch circuit and the second branch circuit when the voltage detected by the second detection unit is in a second high-voltage state, and switches the first cut-off unit from the first release state to the first cut-off state.

[0029] In the vehicle cut-off control device of [8] described above, the control unit can determine whether current does not flow to at least one of the first branch circuit and the second branch circuit based on the voltage detected by the second detection unit by setting the semiconductor circuit breaker to the third cut-off state. When it is determined that current does not flow to at least one of the first branch circuit and the second branch circuit, it can be presumed that a discharge overcurrent via the load has occurred. In such a case, by switching the first cut-off unit to the first cut-off state, the discharge overcurrent via the load can be prevented from flowing.

[0030] <First Embodiment>

[0031] 〔Structure of Vehicle Power Supply System〕

[0032] Figure 1 The vehicle power supply system 100 shown is a power supply system mounted on a vehicle, and includes a power storage unit 10, a load 20, a charging unit 30, and a vehicle cut-off control device 40. The vehicle power supply system 100 is configured to be able to supply power from the power storage unit 10 to the load 20, and is also configured to be able to supply power from the charging unit 30 to the power storage unit 10.

[0033] The vehicle power supply system 100 further includes a first conductive circuit 11, a second conductive circuit 12, a first branch circuit 11B, and a second branch circuit 12B. The first conductive circuit 11 has a first common path 11A and a third branch circuit 11C. The second conductive circuit 12 has a second common path 12A and a fourth branch circuit 12C.

[0034] The first conductive circuit 11 is provided between the high-potential side terminal of the power storage unit 10 and the high-potential side terminal of the load 20. The second conductive circuit 12 is provided between the low-potential side terminal of the power storage unit 10 and the low-potential side terminal of the load 20.

[0035] The first common path 11A is provided between the power storage unit 10 and the first branch circuit 11B. The second common path 12A is provided between the power storage unit 10 and the second branch circuit 12B.

[0036] The first branch circuit 11B branches from the first conductive circuit 11 and is provided between the first conductive circuit 11 and the high-potential side terminal of the charging unit 30. The second branch circuit 12B branches from the second conductive circuit 12 and is provided between the second conductive circuit 12 and the low-potential side terminal of the charging unit 30.

[0037] The third branch circuit 11C is provided between the first branch circuit 11B and the load 20. The fourth branch circuit 12C is provided between the second branch circuit 12B and the load 20.

[0038] The power storage unit 10 uses, for example, a power supply unit such as a lead storage battery or a lithium ion battery. A high-potential side terminal and a low-potential side terminal are provided in the power storage unit 10. The high-potential side terminal of the power storage unit 10 is electrically connected to one end of the first conduction path 11 (specifically, one end of the first common path 11A). The low-potential side terminal of the power storage unit 10 is electrically connected to one end of the second conduction path 12 (specifically, one end of the second common path 12A). The power storage unit 10 applies an output voltage with the low-potential side terminal as a reference to the first conduction path 11 (specifically, the first common path 11A).

[0039] In the present disclosure, the so-called "electrically connected" preferably refers to a structure in which the two connection objects are connected in a mutually conductive state (a state in which current flows) such that the potentials of the two connection objects are equal. However, the structure is not limited to this. For example, "electrically connected" may also be a structure in which an electrical component is interposed between two connection objects and the two connection objects are connected in a conductive state.

[0040] The load 20 is, for example, an in-vehicle electrical device. The load 20 is, for example, an electric motor, a compressor, a PTC thermistor, or the like.

[0041] The charging unit 30 is configured as a charger that charges the power storage unit 10. The charging unit 30 is configured as, for example, a quick charger (quick charging station). The charging unit 30 supplies power to the power storage unit 10 via a charging connector mounted on the vehicle.

[0042] The vehicle power supply system 100 further includes switches 81, 82, 83, 84. The switches 81, 82, 83, 84 are configured as, for example, relays. The switches 81, 82 are respectively provided in the first conduction path 11 and the second conduction path 12. The switches 83, 84 are respectively provided in the first branch path 11B and the second branch path 12B.

[0043] The vehicle cut-off control device 40 includes a first cut-off unit 41, a second cut-off unit 42, a control unit 50, a first drive circuit 61, a second drive circuit 62, a first detection unit 71, and a second detection unit 72.

[0044] The first cut-off part 41 is configured as a pyrotechnic circuit breaker. The first cut-off part 41 is provided in the second common path 12A. The first cut-off part 41 is a cutter that physically cuts off the second common path 12A based on a control signal. The first cut-off part 41 is a pyrotechnic fuse (PYROFUSE (registered trademark)) that is broken by the explosion of gunpowder based on the control signal output from the control part 50 described later, thereby cutting off the second common path 12A. The first cut-off part 41 switches from the first release state that releases the first cut-off state to the first cut-off state that cuts off the second common path 12A. When the first cut-off part 41 becomes the first cut-off state, an explosion occurs, and the displacement part is moved by this explosion, thereby physically cutting off the path. One end of the first cut-off part 41 is electrically connected to the low-potential side terminal of the power storage part 10. The other end of the first cut-off part 41 is electrically connected to one end of the second cut-off part 42 and the low-potential side terminal of the load 20.

[0045] The second cut-off part 42 is configured as a pyrotechnic circuit breaker. The second cut-off part 42 is provided in the second branch path 12B. The second cut-off part 42 is a cutter that physically cuts off the second branch path 12B based on a control signal. The second cut-off part 42 is a pyrotechnic fuse (PYROFUSE (registered trademark)) that is broken by the explosion of gunpowder based on the control signal output from the control part 50 described later, thereby cutting off the second branch path 12B. The second cut-off part 42 switches from the second release state that releases the second cut-off state to the second cut-off state that cuts off the second branch path 12B. When the second cut-off part 42 becomes the second cut-off state, an explosion occurs, and the displacement part is moved by this explosion, thereby physically cutting off the path. The other end of the second cut-off part 42 is electrically connected to the low-potential side terminal of the charging part 30.

[0046] The control part 50 controls the operation of supplying power from the power storage part 10 to the load 20. The control part 50 controls the operation of supplying power from the charging part 30 to the power storage part 10. The control part 50 is an information processing device having information processing functions, arithmetic functions, control functions, etc. The control part 50 is constituted mainly by a microcomputer, for example, and has an arithmetic device such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), an A / D converter, etc. The control part 50 controls the operations of the first cut-off part 41 and the second cut-off part 42 based on the detection signals detected by the first detection part 71 and the second detection part 72 described later.

[0047] The control unit 50 controls the cutting operation of the first cutting unit 41. The control unit 50 switches the first cutting unit 41 from the first release state to the first cutting state. The control unit 50 outputs a control signal (first control signal) to cause the first cutting unit 41 to cut the second common path 12A. During the period when the control unit 50 outputs a second control signal different from the first control signal, the control unit 50 does not perform the cutting of the second common path 12A by the first cutting unit 41. The first control signal is, for example, a high-level signal (a signal with a voltage greater than 0V). The second control signal is, for example, a low-level signal (a voltage smaller than the high-level signal, for example, 0V).

[0048] The control unit 50 controls the cutting operation of the second cutting unit 42. The control unit 50 switches the second cutting unit 42 from the second release state to the second cutting state. The control unit 50 outputs a control signal (third control signal) to cause the second cutting unit 42 to cut the second branch path 12B. During the period when the control unit 50 outputs a fourth control signal different from the third control signal, the control unit 50 does not perform the cutting of the second branch path 12B by the second cutting unit 42. The third control signal is, for example, a high-level signal (a signal with a voltage greater than 0V). The fourth control signal is, for example, a low-level signal (a voltage smaller than the high-level signal, for example, 0V).

[0049] The first drive circuit 61 is electrically connected to the output terminal of the control unit 50 and the first cutting unit 41. The first drive circuit 61 can adopt various circuit structures using resistors, diodes, bipolar transistors, etc. The first drive circuit 61 is input with a control signal from the control unit 50. The first drive circuit 61 is a circuit capable of switching from the output of a second voltage signal (for example, a low-level signal) to the output of a first voltage signal (for example, a high-level signal), where the second voltage signal is used to make the first cutting unit 41 in a state where it does not perform the cutting operation, and the first voltage signal is used to make the first cutting unit 41 perform the cutting operation. In the state where the first cutting unit 41 does not perform the cutting operation, when the control unit 50 outputs the second control signal, the first drive circuit 61 outputs the second voltage signal to maintain the state where the first cutting unit 41 does not perform the cutting operation. When the control unit 50 outputs the first control signal, the first drive circuit 61 outputs the first voltage signal, and the first cutting unit 41 performs the cutting operation.

[0050] The second drive circuit 62 is electrically connected to the output terminal of the control unit 50 and the second cut-off unit 42. The second drive circuit 62 can adopt various circuit structures using resistors, diodes, bipolar transistors, etc. The second drive circuit 62 is input with a control signal from the control unit 50. The second drive circuit 62 is a circuit capable of switching from the output of a fourth voltage signal (for example, a low-level signal) to the output of a third voltage signal (for example, a high-level signal), where the fourth voltage signal is used to make the second cut-off unit 42 be in a state where no cut-off operation is performed, and the third voltage signal is used to make the second cut-off unit 42 perform a cut-off operation. In a state where the second cut-off unit 42 does not perform a cut-off operation, when the control unit 50 outputs a fourth control signal, the second drive circuit 62 outputs a fourth voltage signal to maintain the state where the second cut-off unit 42 does not perform a cut-off operation. When the control unit 50 outputs a third control signal, the second drive circuit 62 outputs a third voltage signal, and the second cut-off unit 42 performs a cut-off operation.

[0051] The first detection unit 71 is provided in the second common path 12A. The first detection unit 71 detects the current value of the current flowing through the second common path 12A and the direction (direction) of the current flowing through the second common path 12A. The current value detected by the first detection unit 71 is a value capable of determining the current value of the second common path 12A (specifically, an analog voltage value). The first detection unit 71 is configured as a current sensor (current detection circuit), for example. Specifically, the first detection unit 71 is provided between the power storage unit 10 and the first cut-off unit 41 in the second common path 12A. The current value and the direction (direction) of the current detected by the first detection unit 71 are output to the control unit 50.

[0052] The second detection unit 72 is provided in the second branch path 12B. The second detection unit 72 detects the current value of the current flowing through the second branch path 12B and the direction (direction) of the current flowing through the second branch path 12B. The second detection unit 72 detects the situation where the current flows into the second branch path 12B based on the current flowing into the second branch path 12B. The current value detected by the second detection unit 72 is a value capable of determining the current value of the second branch path 12B (specifically, an analog voltage value). The second detection unit 72 is configured as a current sensor (current detection circuit), for example. Specifically, the second detection unit 72 is provided between the second cut-off unit 42 and the second conduction path 12 in the second branch path 12B. The current value and the direction (direction) of the current detected by the second detection unit 72 are output to the control unit 50.

[0053] 〔Operation of the Vehicle Cut-off Control Device〕

[0054] Next, with reference to Figure 2 etc., an example of the operation of the vehicle cut-off control device 40 will be described. Figure 2The flowchart shown is the control executed by the control unit 50 when a specified start condition is satisfied. When the specified start condition is satisfied, for example, it may be when a charging unit 30 is connected to a vehicle equipped with a vehicle power supply system 100 and charging of the power storage unit 10 by the charging unit 30 has started, or it may be other conditions. A signal indicating that charging of the power storage unit 10 by the charging unit 30 has started is provided to the control unit 50 from an external device (for example, an external ECU (Electronic Control Unit)).

[0055] For example, before starting Figure 2 the control shown, the control unit 50 outputs a second control signal, and the first cut-off unit 41 remains in the first released state. In addition, the control unit 50 outputs a fourth control signal, and the second cut-off unit 42 remains in the second released state.

[0056] First, in step S11, the control unit 50 determines, based on the detection result of the first detection unit 71, whether the current value of the current flowing through the second common path 12A is in an increasing state. The increasing state means a state in which the current value of the second common path 12A exceeds a predetermined threshold value, a state in which the increasing speed of the current value of the second common path 12A exceeds a predetermined threshold value, and the like. The control unit 50 repeats the process of step S11 until it determines that the current value of the second common path 12A is in an increasing state.

[0057] When the control unit 50 determines in step S11 that the current value of the current flowing through the second common path 12A is in an increasing state, it enters "Yes" and determines, based on the detection result of the first detection unit 71, whether the direction of the current flowing through the second common path 12A (direction) is the first direction (step S12). The first direction means the direction in which the charging current flows from the high-potential side terminal of the charging unit 30 toward the low-potential side terminal in the second common path 12A. That is, the first direction means the direction in which the current flowing through the first detection unit 71 flows from the high-potential side (the low-potential side terminal side of the power storage unit 10) to the low-potential side (the low-potential side terminal side of the charging unit 30) during normal charging by the charging unit 30.

[0058] When the control unit 50 determines in step S12 that the direction (orientation) of the current flowing through the second common path 12A is the first direction, it proceeds to "Yes" and determines that a charging overcurrent flows from the charging unit 30 (step S13). That is, the control unit 50 determines that a charging overcurrent flows from the charging unit 30 through the first branch path 11B, the first common path 11A, the second common path 12A, and the second branch path 12B. When the current value detected by the first detection unit 71 is in an increasing state and the direction of the current flow detected by the first detection unit 71 is the first direction (the direction of the normal charging current during charging by the charging unit 30), it is assumed that a charging overcurrent flows from the charging unit 30.

[0059] In the next step S14, the control unit 50 causes the second cut-off unit 42 to perform a cut-off operation. That is, the control unit 50 outputs a control signal (third control signal) to cut off the second branch path 12B by the second cut-off unit 42. In this way, by cutting off the second branch path 12B, the charging overcurrent from the charging unit 30 side is prevented, and by maintaining the state of releasing the cut-off of the second common path 12A, the power supply from the power storage unit 10 to the load 20 can be maintained. After step S14, the control unit 50 ends Figure 2 the control.

[0060] On the other hand, when the control unit 50 determines in step S12 that the direction (orientation) of the current flowing through the second common path 12A is not the first direction (is the second direction), it proceeds to "No" and determines whether the current flows to the second branch path 12B based on the detection result of the second detection unit 72 (step S15). For example, when the current value of the second branch path 12B detected by the second detection unit 72 exceeds a predetermined threshold, the control unit 50 determines that the current flows to the second branch path 12B.

[0061] When the control unit 50 determines in step S15 that the current flows to the second branch path 12B, it determines that a discharge overcurrent flows through the charging unit 30 (step S16). That is, the control unit 50 determines that a discharge overcurrent flows through the charging unit 30, and the discharge overcurrent flows through the second branch path 12B, the second common path 12A, the first common path 11A, and the first branch path 11B. When the current value detected by the first detection unit 71 is in an increasing state, the direction of the current flow detected by the first detection unit 71 is the second direction, and the current flows to the second branch path 12B, it is assumed that a discharge overcurrent flows through the charging unit 30.

[0062] In the next step S14, the control unit 50 causes the second cutting unit 42 to perform a cutting operation. In this way, by cutting the second branch path 12B, over-discharge current from the power storage unit 10 side to the charging unit 30 side is prevented, and by maintaining the state where the cutting of the second common path 12A is released, the power supply from the power storage unit 10 to the load 20 can be maintained.

[0063] On the other hand, when the control unit 50 determines in step S15 that no current flows through the second branch path 12B (current flows through the fourth branch path 12C), it is determined that an over-discharge current flowing through the load 20 has occurred (step S17). That is, the control unit 50 determines that an over-discharge current flows through the load 20, and the over-discharge current flows through the first conductive path 11 and the second conductive path 12. When the current value detected by the first detection unit 71 is in an increasing state, the direction of the current detected by the first detection unit 71 is the second direction, and no current flows through the second branch path 12B, it is assumed that an over-discharge current flows from the power storage unit 10 side to the load 20 side.

[0064] In the next step S18, the control unit 50 causes the first cutting unit 41 to perform a cutting operation. That is, the control unit 50 outputs a control signal (first control signal) to cause the first cutting unit 41 to cut the second common path 12A. In this way, by cutting the second common path 12A, the over-discharge current from the power storage unit 10 side to the load 20 side can be blocked. After step S18, the control unit 50 ends Figure 2 the control.

[0065] 〔Effect of the First Embodiment〕

[0066] The following description relates to an example of the effect of the first embodiment.

[0067] In the vehicle cut-off control device 40, by the first detection unit 71 detecting a current with a relatively large current value flowing in the flow from the high-potential side terminal of the charging unit 30 toward the low-potential side terminal (when the current is in an increasing state), the state of the charging over-current flowing from the charging unit 30 can be detected. In addition, by the first detection unit 71 detecting a current with a relatively large current value flowing in the flow from the low-potential side terminal of the charging unit 30 toward the high-potential side terminal (when the current is in an increasing state), and the second detection unit 72 detecting the situation where the current flows through the second branch path 12B, the state of the over-discharge current flowing through the charging unit 30 can be detected. The detection of these states can be achieved by a simple structure in which the first detection unit 71 and the second detection unit 72 are provided. Moreover, by the control of cutting off between the power storage unit 10 and the charging unit 30 and the load 20 by the cutting of the first cutting unit 41, and the control of cutting off between the power storage unit 10 and the charging unit 30 by the cutting of the second cutting unit 42, the detected over-current states can be effectively blocked.

[0068] Further, in the vehicle cut-off control device 40, in the second common path 12A, the direction in which the charging current flows from the high-potential side terminal of the charging unit 30 toward the low-potential side terminal is defined as the first direction. When the current value detected by the first detection unit 71 is in an increasing state and the direction of the current flow detected by the first detection unit 71 is the first direction, the control unit 50 sets the first cut-off unit 41 to the first release state and controls the second cut-off unit 42 to the second cut-off state. When the current value detected by the first detection unit 71 is in an increasing state and the direction of the current flow detected by the first detection unit 71 is the first direction (the direction of the normal charging current during charging by the charging unit 30), it is assumed that a charging overcurrent flows from the charging unit 30. In such a case, by cutting off the second branch path 12B, the charging overcurrent from the charging unit 30 side can be prevented, and by releasing the cut-off of the second common path 12A, the power supply from the power storage unit 10 to the load 20 can be maintained.

[0069] Further, in the vehicle cut-off control device 40, in the second common path 12A, the direction in which the charging current flows from the low-potential side terminal of the charging unit 30 toward the high-potential side terminal is defined as the second direction. When the current value detected by the first detection unit 71 is in an increasing state, the direction of the current flow detected by the first detection unit 71 is the second direction, and the current flows into at least one of the first branch path 11B and the second branch path 12B as detected by the second detection unit 72, the control unit 50 sets the first cut-off unit 41 to the first release state and controls the second cut-off unit 42 to the second cut-off state. When the current value detected by the first detection unit 71 is in an increasing state, the direction of the current flow detected by the first detection unit 71 is the second direction, and the current flows into the second branch path 12B, it is assumed that a discharge overcurrent flowing through the charging unit 30 flows. In such a case, by cutting off the second branch path 12B, the discharge overcurrent from the power storage unit 10 side to the charging unit 30 side can be prevented, and by releasing the cut-off of the second common path 12A, the power supply from the power storage unit 10 to the load 20 can be maintained.

[0070] Moreover, in the vehicle cut-off control device 40, in the second common path 12A, the direction in which the charging current flows from the low-potential side terminal to the high-potential side terminal of the charging unit 30 is set as the second direction. When the current value detected by the first detection unit 71 is in an increasing state, the direction of the current detected by the first detection unit 71 is the second direction, and the second detection unit 72 detects that no current flows into the second branch path 12B, the control unit 50 sets the first cut-off unit 41 to the first cut-off state. In the vehicle cut-off control device 40, when the current value detected by the first detection unit 71 is in an increasing state, the direction of the current detected by the first detection unit 71 is the second direction, and no current flows into the second branch path 12B, it is assumed that a discharge overcurrent flows from the power storage unit 10 side to the load 20 side. In such a case, by cutting off the second common path 12A, the discharge overcurrent from the power storage unit 10 side to the load 20 side can be blocked.

[0071] Moreover, in the vehicle cut-off control device 40, the first detection unit 71 is a current sensor provided on one side of the second common path 12A and configured to detect the current value and the direction of the current flowing through the common path. Thus, with a simple structure of providing a current sensor in the second common path 12A, the overcurrent state of the second common path 12A can be detected.

[0072] Moreover, in the vehicle cut-off control device 40, the second detection unit 72 is a current sensor provided in the second branch path 12B and configured to detect whether current flows into the second branch path 12B based on the current flowing into the second branch path 12B. Thus, whether current flows into the second branch path 12B can be detected with a simple structure of providing a current sensor in the second branch path 12B.

[0073] <Second Embodiment>

[0074] The vehicle power supply system 200 of the second embodiment is mainly different from the first embodiment in that the first semiconductor circuit breaker 243 and the second semiconductor circuit breaker 244 are provided, and the other aspects are common. In addition, the same reference numerals are assigned to the same structures as those in the first embodiment, and detailed descriptions thereof are omitted.

[0075] As Figure 3 shown, the vehicle power supply system 200 includes a power storage unit 10, a load 20, a charging unit 30, and a vehicle cut-off control device 240. The vehicle cut-off control device 240 includes a first cut-off unit 41, a second cut-off unit 42, a first semiconductor circuit breaker 243, a second semiconductor circuit breaker 244, a diode 245, a control unit 50, a first drive circuit 61, a second drive circuit 62, a third drive circuit 63, a first detection unit 71, and a second detection unit 272.

[0076] The first semiconductor circuit breaker 243 is provided in the second common path 12A. The first semiconductor circuit breaker 243 is configured as a semiconductor switch that performs on-off operations. The first semiconductor circuit breaker 243 is, for example, an n-channel type MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). The gate of the first semiconductor circuit breaker 243 is electrically connected to a third drive circuit 63 described later. The source of the first semiconductor circuit breaker 243 is electrically connected to the first cut-off portion 41. The drain of the first semiconductor circuit breaker 243 is electrically connected to the second cut-off portion 42 and the load 20.

[0077] Based on the control signal output from the control unit 50, the first semiconductor circuit breaker 243 switches from the release state (on state) that releases the cut-off state of the second common path 12A to the cut-off state (off state) that cuts off the second common path 12A. Specifically, based on the fifth control signal of the control unit 50, when the fifth voltage signal from the third drive circuit 63 described later is input to the gate, it switches from the release state to the cut-off state. The first semiconductor circuit breaker 243 switches from the cut-off state to the release state based on the control signal (sixth control signal) output from the control unit 50. Specifically, based on the sixth control signal of the control unit 50, when the sixth voltage signal from the third drive circuit 63 is input to the gate, it switches from the cut-off state to the release state.

[0078] The second semiconductor circuit breaker 244 is provided in the second branch path 12B. The second semiconductor circuit breaker 244 has the same structure as the first semiconductor circuit breaker 243. The gate of the second semiconductor circuit breaker 244 is electrically connected to the third drive circuit 63 described later. The source of the second semiconductor circuit breaker 244 is electrically connected to the low-potential side terminal of the charging unit 30. The drain of the second semiconductor circuit breaker 244 is electrically connected to the second cut-off portion 42.

[0079] Based on the control signal output from the control unit 50, the second semiconductor circuit breaker 244 switches from the release state (third release state, on state) that releases the cut-off state of the second branch path 12B to the cut-off state (third cut-off state, off state) that cuts off the second branch path 12B. Specifically, based on the seventh control signal of the control unit 50, when the seventh voltage signal from the third drive circuit 63 described later is input to the gate, it switches from the release state to the cut-off state. The second semiconductor circuit breaker 244 switches from the cut-off state to the release state based on the control signal (eighth control signal) output from the control unit 50. Specifically, based on the eighth control signal of the control unit 50, when the eighth voltage signal from the third drive circuit 63 is input to the gate, it switches from the cut-off state to the release state.

[0080] The diode 245 is connected in parallel with the second semiconductor circuit breaker 244 in the second branch circuit 12B. The diode 245 is configured as, for example, a parasitic diode of the second semiconductor circuit breaker 244. The anode of the diode 245 is electrically connected to the source of the second semiconductor circuit breaker 244 on the low-potential side terminal side of the charging unit 30. The cathode of the diode 245 is electrically connected to the drain of the second semiconductor circuit breaker 244 on the high-potential side terminal side of the charging unit 30.

[0081] The third drive circuit 63 is electrically connected to the output terminal of the control unit 50, the gate of the first semiconductor circuit breaker 243, and the gate of the second semiconductor circuit breaker 244. The third drive circuit 63 is, for example, a gate drive circuit and can adopt various circuit structures using resistors, diodes, bipolar transistors, etc. The third drive circuit 63 is input with a control signal from the control unit 50. The third drive circuit 63 is a circuit capable of switching between the output of a fifth voltage signal (for example, a low-level signal) and the output of a sixth voltage signal (for example, a high-level signal), where the fifth voltage signal is used to set the first semiconductor circuit breaker 243 to the off state and the sixth voltage signal is used to set the first semiconductor circuit breaker 243 to the on state. When the control unit 50 outputs a fifth control signal, the third drive circuit 63 outputs the fifth voltage signal, and the first semiconductor circuit breaker 243 remains in the off state. When the output of the control unit 50 switches from the sixth control signal to the fifth control signal, the fifth voltage signal is output from the third drive circuit 63, and the first semiconductor circuit breaker 243 switches from the on state to the off state. When the control unit 50 outputs a sixth control signal, the third drive circuit 63 outputs the sixth voltage signal, and the first semiconductor circuit breaker 243 remains in the on state. The sixth control signal (for example, a high-level signal) is a voltage signal with a magnitude exceeding the gate threshold voltage of the first semiconductor circuit breaker 243.

[0082] In addition, the third drive circuit 63 is a circuit capable of switching between the output of a seventh voltage signal (e.g., a low-level signal) and the output of an eighth voltage signal (e.g., a high-level signal). The seventh voltage signal is used to set the second semiconductor circuit breaker 244 to an open state, and the eighth voltage signal is used to set the second semiconductor circuit breaker 244 to a closed state. When the control unit 50 outputs a seventh control signal, the third drive circuit 63 outputs the seventh voltage signal, and the second semiconductor circuit breaker 244 remains in the open state. When the output of the control unit 50 switches from the eighth control signal to the seventh control signal, the seventh voltage signal is output from the third drive circuit 63, and the second semiconductor circuit breaker 244 switches from the closed state to the open state. When the control unit 50 outputs an eighth control signal, the third drive circuit 63 outputs the eighth voltage signal, and the first semiconductor circuit breaker 243 remains in the closed state. The eighth control signal (e.g., a high-level signal) is a voltage signal having a magnitude exceeding the gate threshold voltage of the first semiconductor circuit breaker 243.

[0083] The second detection unit 272 detects the voltage across the second semiconductor circuit breaker 244 (the source-drain voltage). The second detection unit 272 is a circuit that outputs an analog voltage value, which is a value capable of determining the voltage across the second semiconductor circuit breaker 244. The second detection unit 272 is, for example, configured as a voltage division circuit, and the value obtained by dividing the voltage value across the second semiconductor circuit breaker 244 by the voltage division circuit may be input to the control unit 50 as a detection value. Specifically, the second detection unit 272 can detect the voltage value of the anode of the diode 245 relative to the cathode and the voltage value of the cathode of the diode 245 relative to the anode.

[0084] Figure 4 is a schematic illustration Figure 3 of the internal structure of the control unit 50. As Figure 4 shown, the control unit 50 includes an overcurrent state latch circuit 251, a state determination circuit 252, a semiconductor circuit breaker control circuit 253, an overcurrent detection circuit 254, and a charge / discharge determination circuit 255. The overcurrent detection circuit 254 outputs a signal to the overcurrent state latch circuit 251 based on the increasing state of the current in the second common path 12A detected by the first detection unit 71. The overcurrent state latch circuit 251 holds information indicating an overcurrent state based on the signal output from the overcurrent detection circuit 254. The overcurrent state latch circuit 251 outputs information indicating an overcurrent state to the semiconductor circuit breaker control circuit 253 and the state determination circuit 252.

[0085] The semiconductor breaker control circuit 253 sends a control signal to the third drive circuit 63. The charge / discharge determination circuit 255 detects the voltage across both ends of the second semiconductor breaker 244 (the voltage between the source and the drain) to determine whether current flows through the second branch 12B. The charge / discharge determination circuit 255 outputs information indicating whether current flows through the second branch 12B to the semiconductor breaker control circuit 253 and the state determination circuit 252.

[0086] Based on the output signal from the overcurrent state latching circuit 251 and the output signal from the charge / discharge determination circuit 255, the state determination circuit 252 determines whether a discharge overcurrent flowing through the charging unit 30 or a discharge overcurrent flowing through the load 20. The state determination circuit 252 outputs a voltage signal to the first drive circuit 61 (the first voltage signal when the first cut-off unit 41 is to be cut off). The state determination circuit 252 outputs a voltage signal to the second drive circuit 62 (the third voltage signal when the second cut-off unit 42 is to be cut off).

[0087] 〔Operation of the vehicle cut-off control device〕

[0088] Next, with reference to Figure 5 etc., an example of the operation of the vehicle cut-off control device 240 will be described. Figure 5 The flowchart shown is the control executed by the control unit 50 when a specified start condition is satisfied. The condition for the specified start condition to be satisfied is the same as that in the first embodiment.

[0089] For example, before starting the Figure 5 shown control, the control unit 50 outputs a second control signal, and the first cut-off unit 41 remains in the first release state. The control unit 50 outputs a fourth control signal, and the second cut-off unit 42 remains in the second release state. The control unit 50 outputs a sixth voltage signal, and the first semiconductor breaker 243 remains in the release state. The control unit 50 outputs an eighth voltage signal, and the second semiconductor breaker 244 remains in the release state.

[0090] The control unit 50 performs steps S11 to S13 in the same manner as in the first embodiment. In the next step S21, the control unit 50 sets the second semiconductor circuit breaker 244 to the cut-off state and causes the second cut-off unit 42 to perform a cut-off operation. That is, the control unit 50 outputs a control signal (seventh control signal, third control signal) to cut off the second branch path 12B through the second semiconductor circuit breaker 244 and the second cut-off unit 42. In this way, by cutting off the second branch path 12B, overcharging current from the charging unit 30 side can be prevented, and by maintaining the state of releasing the cut-off of the second common path 12A, the power supply from the power storage unit 10 to the load 20 can be maintained. Here, the control unit 50 controls in such a way that the cut-off operation of the second cut-off unit 42 is performed after the second semiconductor circuit breaker 244 is switched to the cut-off state. Thereby, the second common path 12A can be cut off at high speed by the second semiconductor circuit breaker 244, and the insulation performance during the cut-off of the second common path 12A can be improved by the second cut-off unit 42. After step S21, the control unit 50 ends Figure 5 the control.

[0091] On the other hand, when the control unit 50 determines in step S12 that the direction (direction) of the current flowing through the second common path 12A is not the first direction (is the second direction), it enters "No" and sets the second semiconductor circuit breaker 244 to the cut-off state (step S22). That is, the control unit 50 outputs a fifth control signal to cut off the second branch path 12B through the second semiconductor circuit breaker 244.

[0092] In the next step S23, the control unit 50 determines whether the voltage detected by the second detection unit 272 (the voltage of the anode of the diode 245 relative to the cathode) is in the first high voltage state. The first high voltage state refers to, for example, a state where the voltage of the anode of the diode 245 relative to the cathode exceeds a specified threshold voltage. The specified threshold voltage refers to, for example, a value slightly smaller than the Vf (forward voltage) of the diode 245, etc. When the discharge current flowing through the charging unit 30 flows into the second common path 12A, the voltage of the anode of the diode 245 relative to the cathode increases by the amount of Vf (forward voltage).

[0093] When the control unit 50 determines in step S23 that the voltage of the anode of the diode 245 relative to the cathode is in the first high voltage state, it enters "Yes" and determines that a discharge overcurrent flowing through the charging unit 30 has occurred (step S16). In this way, when the control unit 50 sets the second semiconductor circuit breaker 244 to the cut-off state, when the voltage detected by the second detection unit 272 (the voltage of the anode of the diode 245 relative to the cathode) is in the first high voltage state, it is determined that the current flows into the second branch path 12B.

[0094] In the next step S24, the control unit 50 causes the second cutting unit 42 to perform a cutting operation. That is, the control unit 50 outputs a third control signal to cut off the second branch path 12B through the second cutting unit 42. In this way, by cutting off the second branch path 12B, overcharging current from the charging unit 30 side is prevented, and by maintaining the state where the cutting of the second common path 12A is released, the power supply from the power storage unit 10 to the load 20 can be maintained. Here, the control unit 50 controls in such a way that the cutting operation of the second cutting unit 42 is performed after the second semiconductor circuit breaker 244 switches to the cut-off state. Thereby, the second branch path 12B can be cut off at high speed by the second semiconductor circuit breaker 244, and the insulation performance during the cutting of the second branch path 12B can be improved by the second cutting unit 42. After step S24, the control unit 50 ends Figure 5 the control.

[0095] On the other hand, when the control unit 50 determines in step S23 that the voltage of the anode of the diode 245 relative to the cathode is not in the first high voltage state (is in the second high voltage state), it enters "No" and determines that a discharge overcurrent flowing through the load 20 flows (step S17). The so-called second high voltage state means, for example, a state where the voltage of the cathode of the diode 245 relative to the anode exceeds a specified second threshold voltage. The so-called specified second threshold voltage is, for example, a value slightly smaller than the output voltage of the charging unit 30. When the discharge current through the charging unit 30 does not flow into the second common path 12A, the voltage of the cathode of the diode 245 relative to the anode increases by the amount of the output voltage of the charging unit 30.

[0096] In the next step S25, the control unit 50 sets the first semiconductor circuit breaker 243 to the cut-off state and causes the first cutting unit 41 to perform a cutting operation. That is, the control unit 50 outputs control signals (fifth control signal, first control signal) to cut off the second common path 12A through the first semiconductor circuit breaker 243 and the first cutting unit 41. In this way, by switching the first cutting unit 41 to the first cut-off state, the discharge overcurrent flowing through the load 20 can be blocked. Here, the control unit 50 controls in such a way that the cutting operation of the first cutting unit 41 is performed after the first semiconductor circuit breaker 243 switches to the cut-off state. Thereby, the second common path 12A can be cut off at high speed by the first semiconductor circuit breaker 243, and the insulation performance during the cutting of the second common path 12A can be improved by the first cutting unit 41. After step S25, the control unit 50 ends Figure 5 the control.

[0097] 〔Effects of the Second Embodiment〕

[0098] The following description relates to an example of the effects of the second embodiment.

[0099] The vehicle cut-off control device 240 includes: a second semiconductor circuit breaker 244 that is switched between a third cut-off state in which the second branch circuit 12B is cut off and a third release state in which the third cut-off state is released by the control of the control unit 50; and a diode 245 that is connected in parallel with the second semiconductor circuit breaker 244 such that the anode is provided on the low-potential side terminal side of the charging unit 30 and the cathode is provided on the high-potential side terminal side of the charging unit 30. The second detection unit 72 detects the voltage of the anode with respect to the cathode. When the second semiconductor circuit breaker 244 is set to the third cut-off state, the control unit 50 determines that current flows into the second branch circuit 12B when the voltage detected by the second detection unit 72 is in the first high-voltage state. In this way, in the vehicle cut-off control device 240, by setting the second semiconductor circuit breaker 244 to the third cut-off state, the control unit 50 can determine whether current flows into the second branch circuit 12B based on the voltage detected by the second detection unit 72. In addition, by setting the second semiconductor circuit breaker 244 to the third cut-off state, the second branch circuit 12B can be cut off at high speed.

[0100] Moreover, in the vehicle cut-off control device 240, the second detection unit 72 detects the voltage of the cathode with respect to the anode. When the second semiconductor circuit breaker 244 is set to the third cut-off state, the control unit 50 determines that current does not flow into the second branch circuit 12B when the voltage detected by the second detection unit 72 is in the second high-voltage state, and switches the first cut-off unit 41 from the first release state to the first cut-off state. Thus, by setting the second semiconductor circuit breaker 244 to the third cut-off state, the control unit 50 can determine whether current does not flow into the second branch circuit 12B based on the voltage detected by the second detection unit 72. When it is determined that current does not flow into the second branch circuit 12B, it can be presumed that a discharge overcurrent has occurred via the load 20. In such a case, by switching the first cut-off unit 41 to the first cut-off state, the discharge overcurrent via the load 20 can be prevented from flowing.

[0101] <Other Embodiments>

[0102] The present disclosure is not limited to the embodiments described above and illustrated in the drawings. For example, the features of the above-described or later-described embodiments can be combined in all combinations without contradiction. In addition, any feature in the above-described and later-described embodiments can be omitted as long as it is not explicitly stated as an essential feature. Moreover, the above-described embodiments can be modified as follows.

[0103] In the structure shown in the above second embodiment Figure 3 as shown Figure 6 it is also possible to change the arrangement of the second cut-off unit 42 and the second semiconductor circuit breaker 244 in the second branch circuit 12B. In addition, in Figures 6 - 10In the figure, illustration of the control unit 50, each drive circuit (the first drive circuit 61, etc.) is omitted, but for the sake of consistency with Figure 4 and Figure 5 it has the same structure.

[0104] In the structure shown in the above-described second embodiment Figure 3 as shown, it is also possible to change the arrangement positions of the switches 81 and 82 to positions closer to the power storage unit 10. The switch 82 is provided in the second common path 12A between the power storage unit 10 and the first cut-off unit 41. Additionally, as Figure 7 shown, it is also possible to change the arrangement positions of the switches 81 and 82 to positions closer to the load 20. The switch 81 is provided between the first branch path 11B and the load 20. The switch 82 is provided between the second branch path 12B and the load 20. Figure 9 In the configuration relationship between the second cut-off unit 42 and the second semiconductor circuit breaker 244 in

[0105] as Figure 8 and Figure 10 shown, it is also possible to set the same arrangement relationship of the switches 81 and 82 as that in Figure 6 and Figure 7 and Figure 10 .

[0106] In the above-described first and second embodiments, the first cut-off unit 41 is provided in the second common path 12A, but it may also be a structure provided only in the first common path 11A or provided in both the first common path 11A and the second common path 12A. Similarly, the second cut-off unit 42 is provided in the second branch path 12B, but it may also be a structure provided only in the first branch path 11B or provided in both the first branch path 11B and the second branch path 12B.

[0107] In the above-described first and second embodiments, the first detection unit 71 is provided in the second common path 12A, but it may also be provided only in the first common path 11A or provided in both the first common path 11A and the second common path 12A. The second detection unit 72 is provided in the second branch path 12B, but as long as it can detect the current flowing through the first branch path 11B, it may also be provided only in the first branch path 11B or provided in both the first branch path 11B and the second branch path 12B.

[0108] In the above-described second embodiment, the first semiconductor circuit breaker 243 is provided in the second common path 12A, but it may also be provided only in the first common path 11A or provided in both the first common path 11A and the second common path 12A.

[0109] In the above-described first embodiment, in Figure 2In step S18, the first cutting portion 41 performs a cutting operation, but the second cutting portion 42 may further perform a cutting operation. In the above-described second embodiment, in Figure 5 step S25, the first semiconductor circuit breaker 243 and the first cutting portion 41 perform cutting, but the second cutting portion 42 may further perform cutting.

[0110] In the above-described second embodiment, a structure in which the first semiconductor circuit breaker 243 and the second semiconductor circuit breaker 244 are n-channel MOSFETs is illustrated, but other semiconductor switches such as an IGBT (Insulated Gate Bipolar Transistor) may be used.

[0111] In the above-described second embodiment, the internal structure of the control unit 50 is illustrated, but the control unit 50 of the first embodiment may also have the same internal structure.

[0112] In addition, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein and is intended to include all modifications within the scope shown by the claims or equivalent to the scope of the claims.

[0113] Reference Numerals 10... Power storage unit 11... First conduction path 11A... First common path 11B... First branch path 11C... Third branch path 12... Second conduction path 12A... Second common path 12B... Second branch path 12C... Fourth branch path 20... Load 30... Charging unit 40... Vehicle cutting control device 41... First cutting portion 42... Second cutting portion 50... Control unit 51... Semiconductor circuit breaker 51... First cutting portion 52... Second cutting portion 61... First drive circuit 62... Second drive circuit 63... Third drive circuit 71... First detection unit 72... Second detection unit 81, 82, 83, 84... Switch 100... Vehicle power supply system 200... Vehicle power supply system 240... Vehicle cut-off control device 243... First semiconductor circuit breaker 244... Second semiconductor circuit breaker (semiconductor circuit breaker) 245... Diode 251... Overcurrent state latching circuit 252... State determination circuit 253... Semiconductor circuit breaker control circuit 254... Overcurrent detection circuit 255... Charge / discharge determination circuit 272... Second detection unit.

Claims

1. A cut-off control device for a vehicle, which is used in a vehicle power supply system. The vehicle power supply system includes: a power storage unit that is charged by a charging unit; and a load that is supplied with power from the power storage unit. Wherein, The vehicle power supply system includes: a first conductive path provided between the high-potential side terminal of the power storage unit and the high-potential side terminal of the load; a second conductive path provided between the low-potential side terminal of the power storage unit and the low-potential side terminal of the load; a first branch path branched from the first conductive path and provided between the first conductive path and the high-potential side terminal of the charging unit; and a second branch path branched from the second conductive path and provided between the second conductive path and the low-potential side terminal of the charging unit. The first conductive path has: a first common path provided between the power storage unit and the first branch path; and a third branch path provided between the first branch path and the load. The second conductive path has: a second common path provided between the power storage unit and the second branch path; and a fourth branch path provided between the second branch path and the load. The cut-off control device for a vehicle includes: A first cut-off unit that switches from a first release state to a first cut-off state. The first cut-off state is a state in which at least one of the first common path and the second common path is cut off, and the first release state is a state in which the first cut-off state is released. A second cut-off unit that switches from a second release state to a second cut-off state. The second cut-off state is a state in which at least one of the first branch path and the second branch path is cut off, and the second release state is a state in which the second cut-off state is released. A first detection unit that detects the current value flowing through at least one of the first common path and the second common path and the direction of current flow. A second detection unit that detects the situation where current flows into at least one of the first branch path and the second branch path. And A control unit that, based on the detection signals detected by the first detection unit and the second detection unit, causes the first cut-off unit to switch from the first release state to the first cut-off state and causes the second cut-off unit to switch from the second release state to the second cut-off state.

2. The cut-off control device for a vehicle according to claim 1, Wherein, In at least one of the first common path and the second common path, the direction of the charging current flowing from the high-potential side terminal of the charging unit toward the low-potential side terminal is set as the first direction. When the current value detected by the first detection unit is in an increasing state and the direction of the current flow detected by the first detection unit is the first direction, the control unit sets the first cut-off unit to the first release state and controls the second cut-off unit to the second cut-off state.

3. The cut-off control device for a vehicle according to claim 1 or claim 2, Wherein, In at least one of the first common path and the second common path, the direction of the charging current flowing from the low-potential side terminal of the charging unit toward the high-potential side terminal is set as the second direction. When the current value detected by the first detection unit is in an increasing state, the direction of the current flow detected by the first detection unit is the second direction, and the second detection unit detects that the current flows into at least one of the first branch path and the second branch path, the first cut-off unit is set to the first release state and the second cut-off unit is controlled to the second cut-off state.

4. The vehicle cut-off control device according to claim 1 or claim 2, wherein, in at least one of the first common path and the second common path, the direction of the charging current flowing from the low-potential side terminal to the high-potential side terminal of the charging unit is set as the second direction, when the current value detected by the first detection unit is in an increasing state, the direction of the current flow detected by the first detection unit is the second direction, and the second detection unit detects that the current does not flow into at least one of the first branch path and the second branch path, the first cut-off unit is set to the first cut-off state.

5. The vehicle cut-off control device according to claim 1 or claim 2, wherein, the first detection unit is a current sensor, and the current sensor is provided in one of the first common path and the second common path and detects the current value and the direction of the flowing current of the common path.

6. The vehicle cut-off control device according to claim 1 or claim 2, wherein, the second detection unit is a current sensor that is provided in one of the first branch path and the second branch path or in one of the third branch path and the fourth branch path, and based on the current flowing into at least one of the first branch path and the second branch path or at least one of the third branch path and the fourth branch path, detects the situation where the current flows into at least one of the first branch path and the second branch path.

7. The vehicle cut-off control device according to claim 1 or claim 2, wherein, the vehicle cut-off control device includes: a semiconductor circuit breaker that is switched between a third cut-off state and a third release state by the control of the control unit, the third cut-off state being a state in which at least one of the first branch path and the second branch path is cut off, and the third release state being a state in which the third cut-off state is released; and a diode that is connected in parallel with the semiconductor circuit breaker in such a manner that the anode is provided on the low-potential side terminal side of the charging unit and the cathode is provided on the high-potential side terminal side of the charging unit, the second detection unit detects the voltage of the anode with respect to the cathode, when the semiconductor circuit breaker is set to the third cut-off state, the control unit determines that the current flows into at least one of the first branch path and the second branch path when the voltage detected by the second detection unit is in a first high voltage state.

8. The vehicle cut-off control device according to claim 1 or claim 2, wherein, the vehicle cut-off control device includes: A semiconductor circuit breaker that switches between a third cut-off state and a third release state by control performed by the control unit, where the third cut-off state is a state in which at least one of the first branch circuit and the second branch circuit is cut off, and the third release state is a state that releases the third cut-off state; and A diode is connected in parallel with the semiconductor circuit breaker in such a way that the anode is provided on the low-potential side terminal side of the charging unit and the cathode is provided on the high-potential side terminal side of the charging unit, The second detection unit detects the voltage of the cathode with respect to the anode, When the semiconductor circuit breaker is set to the third cut-off state, the control unit determines that no current flows through at least one of the first branch circuit and the second branch circuit when the voltage detected by the second detection unit is in a second high voltage state, and switches the first cut-off unit from the first release state to the first cut-off state.

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