Battery disconnection system and failure detection method

Abstract

This battery disconnection system comprises: a main relay connected between a battery and a load; a serially-connected precharge relay and a precharge resistor that are connected in parallel with the main relay; a current sensor that measures the current in the battery; a pyrotechnic interrupter for interrupting battery current; a voltage measurement unit that measures the voltage of the precharge resistor; and a control circuit. The control circuit controls the pyrotechnic interrupter on the basis of the measurement value of the current sensor when the main relay is on, and detects a failure of the current sensor on the basis of the measurement value of the voltage measurement unit when the main relay is off and the precharge relay is on.

Description

Battery disconnect system and fault detection method

[0001] The present disclosure relates to a battery disconnect system and a fault detection method.

[0002] Patent Document 1 describes a system that causes a fuse to interrupt the flow of current based on a detected current detected by a current sensor.

[0003] JP 2015-91199 A

[0004] In the system described in Patent Document 1, if the current sensor fails, the system may be erroneously shut off even when no overcurrent is flowing due to erroneous current detection, or may not be shut off even when an overcurrent is flowing. For example, it is possible to provide multiple current sensors for redundancy in order to detect a current sensor failure, but this increases costs.

[0005] Therefore, the present disclosure provides a battery cutoff system and the like that can detect a failure of a current sensor without providing multiple current sensors.

[0006] A battery cutoff system according to one aspect of the present disclosure includes a main relay connected between a battery and a load, a pre-charge relay and a pre-charge resistor connected in series and in parallel with the main relay, a current sensor that measures the current of the battery, a pyrotechnic cutoff device for cutting off the current of the battery, a voltage measurement unit that measures the voltage of the pre-charge resistor, and a control circuit, wherein the control circuit controls the pyrotechnic cutoff device based on the measurement value of the current sensor when the main relay is on, and detects a failure of the current sensor based on the measurement value of the voltage measurement unit when the main relay is off and the pre-charge relay is on.

[0007] A fault detection method according to one aspect of the present disclosure is a method for detecting a fault in a current sensor executed by a battery cutoff system including a main relay connected between a battery and a load, a pre-charge relay and a pre-charge resistor connected in series and in parallel with the main relay, a current sensor that measures the current of the battery, and a pyrotechnic cutoff device that cuts off the current of the battery, the method including the steps of measuring the voltage of the pre-charge resistor when the main relay is off and the pre-charge relay is on, and detecting a fault in the current sensor based on the measured value measured in the measuring step.

[0008] According to a battery cutoff system according to one aspect of the present disclosure, a failure of a current sensor can be detected without providing multiple current sensors.

[0009] Fig. 1 is a configuration diagram showing an example of a battery cutoff system according to embodiment 1. Fig. 2 is a configuration diagram showing an example of a battery cutoff system according to a modified example of embodiment 1. Fig. 3 is a configuration diagram showing an example of a battery cutoff system according to embodiment 2. Fig. 4 is a configuration diagram showing an example of a battery cutoff system according to a modified example of embodiment 2. Fig. 5 is a flowchart showing an example of a fault detection method according to another embodiment.

[0010] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0011] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0012] First Embodiment A battery shutoff system 1 according to a first embodiment will be described below with reference to FIG.

[0013] Fig. 1 is a configuration diagram showing an example of a battery cutoff system 1 according to embodiment 1. In addition to the battery cutoff system 1, Fig. 1 also shows a battery 10, a smoothing capacitor 20, and an inverter 30. The battery 10, the smoothing capacitor 20, or the inverter 30 may be components of the battery cutoff system 1.

[0014] The battery cutoff system 1 is mounted on a vehicle such as an electric vehicle that uses electric power for propulsion. A high-voltage battery 10 is mounted on a vehicle such as an electric vehicle, and power is supplied from the battery 10 to a load to propel the vehicle. In the event of an accident or the like, a large current may flow through a path connecting the battery 10 to the load due to an abnormality such as a short circuit, which could cause the battery 10 to smoke or catch fire. Therefore, the battery cutoff system 1 is provided to cut off this path. In the following, a smoothing capacitor 20 and an inverter 30 are shown as examples of a load.

[0015] The smoothing capacitor 20 smoothes the current from the battery 10, and the inverter 30 converts the direct current from the battery 10 into alternating current, which allows the motor to be driven by the alternating current and propel the vehicle.

[0016] The battery cutoff system 1 includes main relays 40 and 41, a pre-charge relay 42, a pre-charge resistor 43, a current sensor 50, a pyrotechnic cutoff device 60, and a control board 70. The control board 70 is provided with an ignition circuit 71, a control circuit 73, an amplifier circuit 74, a voltage measurement unit 75, a communication interface 80, and the like.

[0017] The main relays 40 and 41 are provided on a path connecting the battery 10 and the load, and when the main relays 40 and 41 are turned on, they can supply power from the battery 10 to the load. Note that when a relay is turned on, it means that the relay is in a conducting state, and when a relay is turned off, it means that the relay is in a non-conducting state.

[0018] Note that if both main relays 40 and 41 are turned on when starting the vehicle, an inrush current will flow. Therefore, the battery cutoff system 1 is provided with a pre-charge relay 42 and a pre-charge resistor 43 as a countermeasure against the inrush current.

[0019] The precharge relay 42 and the precharge resistor 43 are connected in series, and the circuit in which the precharge relay 42 and the precharge resistor 43 are connected in series is connected in parallel with the main relay 40. For example, when starting the vehicle, the main relay 40 is turned off, the main relay 41 is turned on, and the precharge relay 42 is turned on. This allows current to flow to the load via the precharge resistor 43, thereby suppressing the occurrence of inrush current. For example, in about 0.1 seconds, the voltage of the smoothing capacitor 20 becomes approximately the same as the voltage of the battery 10, the precharge relay 42 is turned off, and the main relay 40 is turned on, thereby starting normal operation. For example, the main relays 40 and 41 and the precharge relay 42 are controlled by an ECU (Electronic Control Unit) or the like outside the battery cutoff system 1.

[0020] The main relays 40, 41 and the pre-charge relay 42 are mechanical relays (contact relays). In this embodiment, the main relays 40, 41 and the pre-charge relay 42 can be other types of relays (for example, semiconductor relays or contactless relays). However, in order to reliably switch between interrupting and supplying a large current from a large-capacity battery mounted on an electric vehicle such as a hybrid electric vehicle or a pure electric vehicle, it is more preferable that the main relays 40, 41 and the pre-charge relay 42 be mechanical relays. In particular, it is more preferable that the main relays 40, 41 be mechanical relays rather than the pre-charge relay 42.

[0021] The current sensor 50 measures the current of the battery 10 (specifically, the current flowing in the path connecting the battery 10 and the load). The current sensor 50 is, for example, a shunt resistor, and measures the current of the battery 10 by converting the current flowing in the resistive element of the shunt resistor into a voltage. For example, the resistance value of the resistive element of the shunt resistor is small, on the order of several tens of micro-ohms, and the generated voltage is also small, so the current sensor 50 may include an amplifier circuit. Note that the battery cutoff system 1 also includes an amplifier circuit 74 in addition to the amplifier circuit.

[0022] Other types (e.g., a current sensor using a Hall element) besides a shunt resistor (shunt type) can also be used for the current sensor 50. However, in terms of ease of installation in the battery cutoff system 1, it is more preferable to use a shunt resistor (shunt type), which can be made smaller than a current sensor using a Hall element.

[0023] The pyrotechnic cutoff device 60 is a device for cutting off the current of the battery 10. Specifically, the pyrotechnic cutoff device 60 is provided on a path connecting the battery 10 and a load, and is a device for cutting off the path. The pyrotechnic cutoff device 60 is, for example, a pyro fuse.

[0024] The voltage measurement unit 75 measures the voltage of the precharge resistor 43. In the first embodiment, as shown in FIG. 1 , the voltage measurement unit 75 includes a first voltage sensor 72 that measures the voltage across the precharge resistor 43.

[0025] The communication interface 80 is an interface for communicating with a higher-level system than the battery cutoff system 1 .

[0026] The control circuit 73 is a circuit for cutting off the current of the battery 10 and for detecting a failure of the current sensor 50. The control circuit 73 is realized by, for example, a microcomputer (MCU: Micro Controller Unit) or the like.

[0027] The control circuit 73 controls the pyrotechnic cutoff device 60 based on the measurement value of the current sensor 50 when the main relay 40 is on (i.e., during normal operation). Specifically, the control circuit 73 controls the pyrotechnic cutoff device 60 to cut off the path connecting the battery 10 and the load when the measurement value of the current sensor 50 satisfies a predetermined condition. The predetermined condition is not particularly limited, but may be a condition in which the measurement value of the current sensor 50 reaches a value corresponding to the current that should cut off the path. For example, the control circuit 73 controls the pyrotechnic cutoff device 60 via an ignition circuit 71. The ignition circuit 71 controls the pyrotechnic cutoff device 60 in response to the output signal from the control circuit 73 when the output signal from the control circuit 73 is small and the pyrotechnic cutoff device 60 cannot be driven by the control circuit 73 alone. Note that if the control circuit 73 can control the pyrotechnic cutoff device 60 alone, the ignition circuit 71 may not be provided.

[0028] Furthermore, the control circuit 73 detects a failure of the current sensor 50 based on the measurement value of the voltage measurement unit 75 when the main relay 40 is off and the pre-charge relay 42 is on (i.e., when measures against inrush current are being taken before the start of normal operation). When a current flows through the pre-charge resistor 43 and the voltage measurement unit 75 measures a voltage equal to or greater than a predetermined value, the control circuit 73 can recognize that the pre-charge relay 42 is on and the main relay is off.

[0029] The control circuit 73 calculates the current from the measurement value of the first voltage sensor 72 and the resistance value of the precharge resistor 43 during the period from when the precharge relay 42 changes from off to on until when it changes from on to off a certain time later (e.g., 0.1 s), and compares the calculated current with the measurement value of the current sensor 50 to detect a fault in the current sensor 50. For example, if the calculated current (i.e., the current flowing through the precharge resistor 43) and the measurement value of the current sensor 50 (i.e., the current flowing through the current sensor 50 (shunt resistor)) approximately match, the control circuit 73 determines that the current sensor 50 is not faulty. On the other hand, if they do not approximately match, the control circuit 73 detects a fault in the current sensor 50. This is because if the current sensor 50 is not faulty, the current flowing through the current sensor 50 and the current flowing through the precharge resistor 43 approximately match.

[0030] The measurement value of the first voltage sensor 72 and the measurement value of the current sensor 50 are values ​​measured at approximately the same timing. The timing of measurement of the first voltage sensor 72 and the measurement value of the current sensor 50 is not particularly limited, but may be as early as possible after the pre-charge relay 42 is turned on from off, because the smoothing capacitor 20 is gradually charged and the flowing current becomes smaller after the pre-charge relay 42 is turned on from off. Furthermore, the measurement value of the first voltage sensor 72 and the measurement value of the current sensor 50 may be an average value obtained at multiple timings.

[0031] Although the example has been described in which the control circuit 73 detects a fault in the current sensor 50 by comparing the measurement value of the current sensor 50 with the current calculated from the measurement value of the voltage measurement unit 75, this is not limiting. For example, the control circuit 73 may detect a fault in the current sensor 50 by comparing the gradient of the time change in the measurement value of the current sensor 50 with the gradient of the time change in the measurement value of the voltage measurement unit 75. When the measurement values ​​themselves are compared, the detection accuracy of the current sensor 50 may be reduced due to the influence of errors in the resistance value, etc. However, when the gradient of the time change in the measurement value is compared, the gradient of the time change is less susceptible to the influence of errors in the resistance value, etc., and a decrease in the detection accuracy of the current sensor 50 can be suppressed.

[0032] Furthermore, the amplifier circuit 74 amplifies the signal from the current sensor 50 when detecting a fault in the current sensor 50. That is, the amplifier circuit 74 amplifies the signal from the current sensor 50 when the main relay 40 is off and the precharge relay 42 is on (i.e., when measures against inrush current are being taken before the start of normal operation). When measures against inrush current are being taken, the current flowing through the current sensor 50 is small, unlike a large current during an abnormality, and the measurement accuracy of the current sensor 50 is poor. Therefore, the signal from the current sensor 50 is amplified by the amplifier circuit 74. The signal from the current sensor 50 amplified by the amplifier circuit 74 is input to the control circuit 73, which detects a fault in the current sensor 50 based on the amplified signal from the current sensor 50 as the measurement value of the current sensor 50. However, if the signal from the current sensor 50 is amplified and input to the control circuit 73 during normal operation, the signal may exceed the measurement range of the control circuit 73, so the amplifier circuit 74 is not used during normal operation.

[0033] Furthermore, for example, when the control circuit 73 detects a failure in the current sensor 50, it notifies the upper system of the abnormality via the communication interface 80. This allows the driver of the vehicle or the like to be notified of the abnormality, thereby improving safety.

[0034] As described above, the battery cutoff system 1 includes the main relay 40 connected between the battery 10 and the load, the pre-charge relay 42 and the pre-charge resistor 43 connected in series and connected in parallel with the main relay 40, the current sensor 50 that measures the current of the battery 10, the pyrotechnic cutoff device 60 for cutting off the current of the battery 10, the voltage measurement unit 75 that measures the voltage of the pre-charge resistor 43, and the control circuit 73. The control circuit 73 controls the pyrotechnic cutoff device 60 based on the measurement value of the current sensor 50 when the main relay 40 is on, and detects a failure of the current sensor 50 based on the measurement value of the voltage measurement unit 75 when the main relay 40 is off and the pre-charge relay 42 is on.

[0035] The battery cutoff system 1 is provided with a pre-charge relay 42 and a pre-charge resistor 43, and measures against inrush current are taken by turning on the pre-charge relay 42 before the main relay 40 is turned on, and causing a current to flow through the pre-charge resistor 43. In the present disclosure, the pre-charge resistor 43 used as a measure against inrush current is also used to detect a failure of the current sensor 50, so that a failure of the current sensor 50 can be detected without providing multiple current sensors 50.

[0036] For example, the control circuit 73 may control the pyrotechnic cutoff device 60 to cut off the path connecting the battery 10 and the load when the measurement value of the current sensor 50 satisfies a predetermined condition.

[0037] In this way, the battery cut-off system 1 can cut off the path connecting the battery 10 and the load using the pyrotechnic cut-off device 60 when the measurement value of the current sensor 50 meets a predetermined condition (specifically, when a large current flows through the current sensor 50).

[0038] For example, the voltage measurement unit 75 may include a first voltage sensor 72 that measures the voltage across the precharge resistor 43 as the voltage across the precharge resistor 43 .

[0039] In this way, the voltage across the precharge resistor 43 may be measured as the voltage across the precharge resistor 43 .

[0040] For example, the control circuit 73 may calculate the current from the measurement value of the first voltage sensor 72 and the resistance value of the precharge resistor 43, and detect a failure of the current sensor 50 by comparing the calculated current with the measurement value of the current sensor 50.

[0041] In this way, the current flowing through the precharge resistor 43 can be calculated from the voltage across the precharge resistor 43 and the resistance value of the precharge resistor 43. By comparing the calculated current flowing through the precharge resistor 43 with the measurement value of the current sensor 50 (specifically, the current flowing through the current sensor 50), if they do not approximately match, it can be detected that the current sensor 50 is faulty.

[0042] For example, the battery cutoff system 1 may further include a communication interface 80 for communicating with a higher-level system. For example, when the control circuit 73 detects a failure in the current sensor 50, the control circuit 73 may notify the higher-level system of the abnormality via the communication interface 80.

[0043] This allows a failure of the current sensor 50 to be notified to a higher-level system.

[0044] For example, the battery cutoff system 1 may further include an amplifier circuit 74 that amplifies the signal of the current sensor 50 when detecting a failure of the current sensor 50. For example, the signal of the current sensor 50 amplified by the amplifier circuit 74 may be input to the control circuit 73, and the control circuit 73 may detect a failure of the current sensor 50 based on the amplified signal of the current sensor 50 as a measurement value of the current sensor 50.

[0045] When detecting a fault in the current sensor 50, the current flowing through the precharge resistor 43 is small. Therefore, the current measured by the current sensor 50 is also small, which reduces the accuracy of detecting a fault in the current sensor 50. Therefore, by amplifying the signal from the current sensor 50 using the amplifier circuit 74, the accuracy of detecting a fault in the current sensor 50 can be improved.

[0046] (Modification of First Embodiment) Next, a battery shutoff system 1a according to a modification of the first embodiment will be described with reference to FIG.

[0047] FIG. 2 is a configuration diagram showing an example of a battery shutoff system 1a according to a modification of the first embodiment.

[0048] In this modification of the first embodiment, the voltage measurement unit 75 differs from the first embodiment in that it includes a first voltage sensor 72 that measures the voltage across the precharge relay 42 and the precharge resistor 43 connected in series as the voltage of the precharge resistor 43. The other configurations are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0049] As in the modification of the first embodiment, the voltage across the series-connected precharge relay 42 and precharge resistor 43 may be measured as the voltage across the precharge resistor 43. This is because the on-resistance of the precharge relay 42 is small and can be ignored, and the voltage across the series-connected precharge relay 42 and precharge resistor 43 can be considered to be the voltage across the precharge resistor 43.

[0050] Accordingly, the control circuit 73 calculates the current from the measurement value of the first voltage sensor 72 and the resistance value of the precharge resistor 43, and detects a failure of the current sensor 50 by comparing the calculated current with the measurement value of the current sensor 50.

[0051] In this way, the current flowing through the precharge resistor 43 can be calculated from the voltage across the series-connected precharge relay 42 and precharge resistor 43 and the resistance value of the precharge resistor 43. The calculated current flowing through the precharge resistor 43 is compared with the measurement value of the current sensor 50 (specifically, the current flowing through the current sensor 50). If they do not approximately match, it can be detected that the current sensor 50 is faulty.

[0052] Second Embodiment Next, a battery cutoff system 2 according to a second embodiment will be described with reference to FIG.

[0053] FIG. 3 is a configuration diagram showing an example of a battery shutoff system 2 according to the second embodiment.

[0054] In the second embodiment, the voltage measurement unit 75 is different from the first embodiment in that it includes a first voltage sensor 72a that measures the voltage of the battery 10 and a second voltage sensor 72b that measures the voltage of the load. The other configurations are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0055] For example, the first voltage sensor 72a measures, as the voltage of the battery 10, the voltage between the node of the main relay 40 and the pre-charge relay 42 on the battery 10 side and the node of the main relay 41 on the battery 10 side. Note that the first voltage sensor 72a may also measure, as the voltage of the battery 10, the voltage between the node of the pyrotechnic cutoff device 60 on the battery 10 side and the node of the main relay 41 on the battery 10 side.

[0056] Furthermore, for example, the second voltage sensor 72b measures the voltage between a node on the load side of the main relay 40 and precharge resistor 43 and a node on the load side of the main relay 41 as the voltage of the load.

[0057] Because the on-resistance of the pre-charge relay 42 and the main relay 41 is small and negligible, the voltage of the pre-charge resistor 43 corresponds to the difference between the measurement value of the first voltage sensor 72a (the voltage of the battery 10) and the measurement value of the second voltage sensor 72b (the voltage of the load). Therefore, measuring the voltage of the battery 10 and the voltage of the load by the voltage measurement unit 75 is equivalent to measuring the voltage of the pre-charge resistor 43.

[0058] In this way, the voltage of the battery 10 and the voltage of the load may be measured as the voltage across the precharge resistor 43 .

[0059] Accordingly, the control circuit 73 calculates the voltage of the precharge resistor 43 from the difference, calculates the current from the calculated voltage of the precharge resistor 43 and the resistance value of the precharge resistor 43, and compares the calculated current with the measurement value of the current sensor 50 to detect a failure of the current sensor 50.

[0060] In this way, the current flowing through the precharge resistor 43 can be calculated from the above difference and the resistance value of the precharge resistor 43, and the calculated current flowing through the precharge resistor 43 can be compared with the measurement value of the current sensor 50 (specifically, the current flowing through the current sensor 50). If they do not approximately match, it can be detected that the current sensor 50 is faulty.

[0061] (Modification of Second Embodiment) Next, a battery shutoff system 2a according to a modification of the second embodiment will be described with reference to FIG.

[0062] FIG. 4 is a configuration diagram showing an example of a battery shutoff system 2a according to a modification of the second embodiment.

[0063] The modification of the second embodiment differs from the second embodiment in that the first voltage sensor 72a and the second voltage sensor 72b share a common reference potential. The other points are the same as those in the second embodiment, and therefore a description thereof will be omitted.

[0064] In order to simplify the circuit compared to the configuration of the second embodiment, the reference potential of the first voltage sensor 72a and the reference potential of the second voltage sensor 72b may be the same. Specifically, as shown in FIG. 4 , the reference potential of the first voltage sensor 72a and the reference potential of the second voltage sensor 72b may each be the potential of a node on the battery 10 side of the main relay 41. Alternatively, the reference potential of the first voltage sensor 72a and the reference potential of the second voltage sensor 72b may each be the potential of a node on the load side of the main relay 41. Furthermore, the reference potential of the first voltage sensor 72a and the reference potential of the second voltage sensor 72b may each be the ground potential of the control board 70.

[0065] In this way, the reference potential of the first voltage sensor 72a and the reference potential of the second voltage sensor 72b may be the same.

[0066] Accordingly, the control circuit 73 calculates the voltage of the precharge resistor 43 from the difference between the measurement value of the first voltage sensor 72a (the voltage of the battery 10) and the measurement value of the second voltage sensor 72b (the voltage of the load), calculates the current from the calculated voltage of the precharge resistor 43 and the resistance value of the precharge resistor 43, and detects a failure of the current sensor 50 by comparing the calculated current with the measurement value of the current sensor 50.

[0067] In this way, the current flowing through the precharge resistor 43 can be calculated from the above difference and the resistance value of the precharge resistor 43, and the calculated current flowing through the precharge resistor 43 can be compared with the measurement value of the current sensor 50 (specifically, the current flowing through the current sensor 50). If they do not approximately match, it can be detected that the current sensor 50 is faulty.

[0068] (Other Embodiments) As described above, the embodiments have been described as examples of the technology according to the present disclosure. However, the technology according to the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. For example, the following modifications are also included in one embodiment of the present disclosure.

[0069] For example, in the above embodiment, an example has been described in which the battery cutoff system includes the amplifier circuit 74 , but the battery cutoff system does not necessarily have to include the amplifier circuit 74 .

[0070] For example, in the above embodiment, an example has been described in which the battery cutoff system includes the communication interface 80 , but the battery cutoff system does not necessarily have to include the communication interface 80 .

[0071] For example, the present disclosure can be realized not only as a battery cutoff system, but also as a fault detection method including steps (processing) performed by components that make up the battery cutoff system.

[0072] FIG. 5 is a flowchart showing an example of a fault detection method according to another embodiment.

[0073] The fault detection method is a current sensor fault detection method executed by a battery cutoff system including a main relay connected between a battery and a load, a pre-charge relay and a pre-charge resistor connected in series and in parallel with the main relay, a current sensor that measures the battery current, and a pyrotechnic cutoff device that cuts off the battery current, and as shown in FIG. 5 , includes a step (step S11) of measuring the voltage of the pre-charge resistor when the main relay is off and the pre-charge relay is on, and a step (step S12) of detecting a fault in the current sensor based on the measured value measured in the measuring step.

[0074] For example, the steps of the fault detection method may be executed by a computer (computer system), and the present disclosure may be realized as a program for causing a computer to execute the steps included in the fault detection method.

[0075] Furthermore, the present disclosure can be realized as a non-transitory computer-readable recording medium, such as a CD-ROM on which the program is recorded.

[0076] For example, when the present disclosure is realized as a program (software), each step is performed by running the program using hardware resources such as a computer's CPU, memory, input / output circuits, etc. In other words, each step is performed by the CPU acquiring data from memory or input / output circuits, etc., performing calculations, and outputting the calculation results to memory or input / output circuits, etc.

[0077] Furthermore, each of the components included in the battery cutoff system of the above-described embodiment may be realized as a dedicated or general-purpose circuit.

[0078] Furthermore, each of the components included in the battery cutoff system of the above-described embodiment may be realized as an LSI (Large Scale Integration) which is an integrated circuit (IC).

[0079] Furthermore, the integrated circuit is not limited to an LSI, and may be realized by a dedicated circuit or a general-purpose processor. A programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor in which the connections and settings of circuit cells within the LSI can be reconfigured may also be used.

[0080] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, that technology may naturally be used to integrate each component included in the battery cutoff system.

[0081] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present disclosure.

[0082] The present disclosure is applicable to a device that interrupts a current flowing in a current path.

[0083] 1, 1a, 2, 2a Battery cutoff system 10 Battery 20 Smoothing capacitor 30 Inverter 40, 41 Main relay 42 Pre-charge relay 43 Pre-charge resistor 50 Current sensor 60 Pyrotechnic cutoff device 70 Control board 71 Ignition circuit 72, 72a First voltage sensor 72b Second voltage sensor 73 Control circuit 74 Amplification circuit 75 Voltage measurement unit 80 Communication interface

Claims

1. A main relay connected between the battery and the load; a precharge relay and a precharge resistor connected in series and connected in parallel with the main relay; a current sensor for measuring a current of the battery; a pyrotechnic interrupter for interrupting the current of the battery; A voltage measurement unit that measures a voltage of the precharge resistor; A control circuit, The control circuit controls the pyrotechnic circuit breaker based on a measurement value of the current sensor when the main relay is on, and detects a failure of the current sensor based on a measurement value of the voltage measurement unit when the main relay is off and the precharge relay is on. Battery disconnect system.

2. The control circuit controls the pyrotechnic cutoff device to cut off a path connecting the battery and the load when a measurement value of the current sensor satisfies a predetermined condition.

2. The battery cutoff system of claim 1.

3. The voltage measurement unit includes a first voltage sensor that measures a voltage across the precharge resistor as the voltage across the precharge resistor.

3. The battery cutoff system according to claim 1 or 2.

4. The control circuit calculates a current from a measurement value of the first voltage sensor and a resistance value of the precharge resistor, and detects a failure of the current sensor by comparing the calculated current with a measurement value of the current sensor.

4. The battery cutoff system of claim 3.

5. The voltage measurement unit has a first voltage sensor that measures a voltage across the precharge relay and the precharge resistor that are connected in series as the voltage across the precharge resistor.

3. The battery cutoff system according to claim 1 or 2.

6. The control circuit calculates a current from a measurement value of the first voltage sensor and a resistance value of the precharge resistor, and detects a failure of the current sensor by comparing the calculated current with a measurement value of the current sensor.

6. The battery cutoff system of claim 5.

7. The voltage measurement unit is a first voltage sensor for measuring a voltage of the battery; a second voltage sensor for measuring a voltage across the load; having The voltage across the precharge resistor corresponds to the difference between the measurement value of the first voltage sensor and the measurement value of the second voltage sensor.

3. The battery cutoff system according to claim 1 or 2.

8. The control circuit calculates a voltage of the pre-charge resistor from the difference, calculates a current from the calculated voltage of the pre-charge resistor and the resistance value of the pre-charge resistor, and compares the calculated current with a measurement value of the current sensor to detect a failure of the current sensor.

8. The battery cutoff system of claim 7.

9. The reference potential of the first voltage sensor and the reference potential of the second voltage sensor are common.

8. The battery cutoff system of claim 7.

10. The control circuit calculates a voltage of the pre-charge resistor from the difference, calculates a current from the calculated voltage of the pre-charge resistor and the resistance value of the pre-charge resistor, and compares the calculated current with a measurement value of the current sensor to detect a failure of the current sensor.

10. The battery cutoff system of claim 9.

11. The battery cutoff system further includes a communication interface for communicating with a higher-level system.

3. The battery cutoff system according to claim 1 or 2.

12. When the control circuit detects a failure of the current sensor, the control circuit notifies the host system of the abnormality via the communication interface.

12. The battery cutoff system of claim 11.

13. The battery cutoff system further includes an amplifier circuit that amplifies a signal of the current sensor upon detecting a failure of the current sensor.

3. The battery cutoff system according to claim 1 or 2.

14. The signal of the current sensor amplified by the amplifier circuit is input to the control circuit, The control circuit detects a failure of the current sensor based on an amplified current sensor signal as a measurement value of the current sensor.

14. The battery cutoff system of claim 13.

15. A method for detecting a fault in a current sensor, which is executed by a battery cutoff system including: a main relay connected between a battery and a load; a pre-charge relay and a pre-charge resistor connected in series and in parallel with the main relay; a current sensor for measuring a current of the battery; and a pyrotechnic cutoff device for cutting off the current of the battery, the method comprising: measuring a voltage across the pre-charge resistor when the main relay is turned off and the pre-charge relay is turned on; and detecting a failure of the current sensor based on the measured value obtained in the measuring step. Fault detection methods.