Current cut-off device

Abstract

The present invention provides a current interrupting device capable of appropriately interrupting a current while suppressing the consumption of a battery. A current interrupting device (1) is provided with: a Hall element (2) that detects the current value of a power supply line (13) that supplies power from a battery (11) to a motor (12); a cutting unit (3) for cutting the power supply line (13); and a cut-off control unit (4) that cuts off the power supply line (13) by operating the cut-off unit (3) on the basis of a detection signal from the Hall element (2), the cut-off control unit (4) being configured so as to have: a voltage / current conversion unit (41) that outputs a current in accordance with the output voltage value of the Hall element (2); a capacitor (42) that is charged in accordance with the output current of the voltage / current conversion unit (41); and an OFF signal output unit (43) that outputs an OFF signal (Vcpm) to the OFF unit (3) when the voltage of the capacitor (42) exceeds a threshold value (Vref).

Description

Technical Field

[0001] The present invention relates to a current interruption device. Background Art

[0002] Conventionally, as a device related to the current cutoff device, there is known a current cutoff system that cuts off the current flowing from the battery to the load, for example, as described in Patent Document 1. The current cutoff system includes a shunt resistor that measures the current value flowing from the battery to the load, and when the current value measured by the shunt resistor exceeds a preset threshold value, the base material between the battery and the load is cut off to cut off the current and protect the battery.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-100339 Summary of the invention

[0006] Technical problem that the invention aims to solve

[0007] In the above-mentioned system, there is room for improvement in that the battery consumption increases. That is, in the above-mentioned system, in order to measure the current value, it is necessary to always allow the current to flow through the shunt resistor, which increases the battery consumption.

[0008] Therefore, an object of the present invention is to provide a current interruption device that can appropriately interrupt a current while suppressing battery consumption.

[0009] Technical solutions to the problem

[0010] That is, the current cut-off device involved in the present invention is constructed as follows: it includes: a Hall element, which detects the current value of the power line that supplies power from a battery to a load; a cut-off unit, which cuts off the power line; and a cut-off control unit, which operates the cut-off unit based on the detection signal of the Hall element to cut off the power line, and the cut-off control unit has: a voltage-current conversion unit, which outputs a current corresponding to the output voltage value of the Hall element; a capacitor, which is charged according to the output current of the voltage-current conversion unit; and a cut-off signal output unit, which outputs a cut-off signal to the cut-off unit when the voltage of the capacitor exceeds a threshold value.

[0011] Effects of the Invention

[0012] According to the current interruption device according to the present invention, it is possible to appropriately interrupt the current while suppressing the consumption of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a circuit diagram schematically showing the configuration of the current interrupt device according to the first embodiment.

[0014] Figure 2 It is a timing chart showing the operation of the current interruption device according to the first embodiment.

[0015] Figure 3 This is a circuit diagram schematically showing the configuration of a current interrupt device according to the second embodiment.

[0016] Figure 4 It is a timing chart showing the operation of the current interruption device according to the second embodiment.

[0017] Figure 5 This is a circuit diagram schematically showing the configuration of a current interrupt device according to a third embodiment.

[0018] Figure 6 It is a timing chart showing the operation of the current interruption device according to the third embodiment.

[0019] Description of Reference Numerals

[0020] 1: Current cut-off device

[0021] 2: Hall element

[0022] 3: Cutting part

[0023] 4: Cut off the control unit

[0024] 11: Battery

[0025] 12: Motor (load)

[0026] 13: Power cord

[0027] 41: Voltage-current conversion unit

[0028] 42: Capacitor

[0029] 43: Cut off signal output

[0030] 47: Constant current circuit

[0031] Vc: voltage

[0032] Vref: Threshold

[0033] Vcmp: Cut off signal DETAILED DESCRIPTION

[0034] Hereinafter, the embodiments of the present invention will be described in detail based on the accompanying drawings. In addition, the present invention is not limited to the embodiments. In addition, the constituent elements in the following embodiments include elements that can be easily replaced by those skilled in the art, or substantially the same elements.

[0035] [Implementation Method]

[0036] This embodiment relates to a current interruption device. Figure 1 As shown, the current interruption device 1 according to the first embodiment is a device for interrupting a power line 13 that supplies power from a battery 11 to a motor 12, and is mounted on an electric vehicle or a hybrid vehicle that uses the motor 12 as a driving source. The current interruption device 1 detects, for example, an overcurrent or a short circuit in the power line 13 connected to the high-voltage battery 11, and interrupts the power line 13 when the overcurrent or the short circuit is detected.

[0037] The battery 11 and the motor 12 are connected via a power cord 13. The battery 11 uses a battery that outputs electric power capable of driving the motor 12. The motor 12 is a load that receives the power supply from the battery 11 and works. The power cord 13 is a transmission line for supplying electric power from the battery 11 to the motor 12, and uses, for example, a covered electric wire in which a conductor is covered with an insulator. The power cord 13 is provided with a cut-off portion 14 and a relay 15. The cut-off portion 14 is a component that cuts off the current of the power cord 13 by being cut off, and, for example, a bus bar is used as the cut-off portion 14. When the power cord 13 is short-circuited or an overcurrent exceeding a specified current value flows in the power cord 13, the cut-off portion 14 is cut off. The relay 15 is a main relay for connecting and disconnecting the power supply to the motor 12.

[0038] The current cutoff device 1 includes a Hall element 2, a cutoff unit 3, and a cutoff control unit 4. The Hall element 2 is a current detection unit that detects the value of the current flowing through the power line 13. For example, the Hall element 2 receives the current of the constant current source 21 and detects the magnetic field formed around the power line 13, thereby detecting the value of the current flowing through the power line 13. The Hall element 2 can be used without passing the current from the battery 11, unlike a shunt resistor, and thus the power consumption of the battery 11 can be suppressed.

[0039] The cut-off section 3 is a unit that cuts off the power line 13, and for example, it works by receiving a cut-off signal from the cut-off control section 4, and cuts off the cut-off section 14 to cut off the power line 13. The cut-off section 3 includes, for example, an ignition section 31, a gunpowder storage section 32, and a cut-off section 33. The ignition section 31 is a component that receives a cut-off signal and ignites the gunpowder stored in the gunpowder storage section 32. For example, the ignition section 31 receives a cut-off signal via a switch element, etc., and ignites the gunpowder stored in the gunpowder storage section 32. The gunpowder storage section 32 is a storage body that stores gunpowder. The cut-off section 33 is a component that cuts off the cut-off section 14 to cut off the power line 13, and for example, it works by the explosive force generated by the ignition of the gunpowder, and abuts against the cut-off section 14 to cut off the cut-off section 14.

[0040] The cutoff control unit 4 is a cutoff control unit that operates the cutoff unit 3 based on the detection signal of the Hall element 2 to cut off the power line 13, and is composed of a cutoff control circuit, for example. The cutoff control unit 4 includes a voltage-current converter 41, a capacitor 42, and a cutoff signal output unit 43.

[0041] The voltage-current conversion unit 41 is a voltage-current conversion circuit that outputs a current corresponding to the output voltage value of the Hall element 2. For example, the voltage-current conversion unit 41 is connected to the output side of the Hall element 2 via the amplifier circuit 44. The amplifier circuit 44 is a circuit that amplifies the detection signal of the Hall element 2. The voltage-current conversion unit 41 inputs a voltage obtained by amplifying the detection signal of the Hall element 2 by the amplifier circuit 44, converts the amplified voltage into a current, and outputs it. The voltage-current conversion unit 41 is configured, for example, using a differential amplifier, and a transistor 45 is connected to the output side of the differential amplifier.

[0042] The capacitor 42 is a capacitor charged according to the output of the Hall element 2. For example, the capacitor 42 is connected to the output side of the voltage-current conversion unit 41 via the first current mirror circuit 46. The first current mirror circuit 46 is a circuit that outputs a current having the same current value as the current output from the voltage-current conversion unit 41. For example, the capacitor 42 is charged by a current having the same current value as the output current of the voltage-current conversion unit 41 via the first current mirror circuit 46. The larger the current output from the voltage-current conversion unit 41, the faster the capacitor 42 is charged, and the longer the output current of the voltage-current conversion unit 41 continues to be output, the larger the charging voltage of the capacitor 42.

[0043] In addition, the capacitor 42 is discharged with a constant current through the constant current circuit 47. For example, the capacitor 42 is connected to the output side of the constant current circuit 47 via the second current mirror circuit 48. Therefore, the capacitor 42 is discharged with a current having the same current value as the output current of the constant current circuit 47 via the second current mirror circuit 48. Thus, when the capacitor 42 is not charged with a current greater than the output current of the constant current circuit 47, the voltage value does not rise.

[0044] The voltage Vc of the capacitor 42 is input to the cutoff signal output unit 43. The cutoff signal output unit 43 is an output circuit that outputs a cutoff signal to the cutoff unit 3 when the voltage Vc of the capacitor 42 exceeds the threshold value Vref. For example, a comparator is used as the cutoff signal output unit 43. The threshold value Vref is, for example, a voltage set by the constant voltage circuit 49. When the voltage Vc of the capacitor 42 exceeds the threshold value Vref, the cutoff signal output unit 43 outputs a cutoff signal to the switch element 34 of the cutoff unit 3 to start the ignition unit 31.

[0045] Next, the operation of the current interruption device 1 according to the first embodiment will be described.

[0046] Figure 2 1 is a timing chart showing the operation of the current interruption device 1 , wherein the horizontal axis represents time and the vertical axis represents the current I of the power line 13 , the voltage Vc of the capacitor 42 , and the output signal Vcmp of the interruption signal output unit 43 . Figure 2 The 100% value shown is the current value of the current I with which the capacitor 42 is charged. That is, when the current I of the power supply line 13 exceeds the 100% value, the capacitor 42 starts to be charged.

[0047] exist Figure 2 In the case where the current I flowing through the power supply line 13 is an overcurrent exceeding 100%, the voltage Vc of the capacitor 42 rises as shown in the time t1-t2. Figure 1 In the process, the detection signal is output from the Hall element 2, the detection signal is amplified by the amplifier circuit 44, and converted into a current by the voltage-current conversion unit 41. Then, a current having the same current value as the output current of the voltage-current conversion unit 41 is output from the first current mirror circuit 46 to charge the capacitor 42. At this time, the capacitor 42 is discharged with the same current value as the output current of the constant current circuit 47. Therefore, the charging current of the capacitor 42 becomes larger than the discharging current, and thus the voltage Vc of the capacitor 42 starts to rise (time t1).

[0048] However, if the current I of the power line 13 decreases before the voltage Vc of the capacitor 42 reaches the threshold value Vref (time t2), the voltage Vc of the capacitor 42 decreases, and the current of the power line 13 is not cut off. Therefore, it is possible to suppress erroneous cutoff of the current cutoff device 1. For example, when a momentary overcurrent such as a surge current flows through the power line 13 and does not cause any trouble to the battery 11 and the relay 15, the current cutoff device 1 does not cut off the current of the power line 13, and unnecessary current cutoff can be suppressed.

[0049] Then, if Figure 2 As shown in the time t3 - t4 , when the motor 12 is driven in a stable state, an overcurrent does not flow through the power line 13 , the capacitor 42 is not charged, and the current of the power line 13 is not cut off.

[0050] In contrast, Figure 2 At time t4, overcurrent begins to flow through the power supply line 13. When the overcurrent continues to flow, the capacitor 42 is charged and the voltage Vc of the capacitor 42 exceeds the threshold value Vref (time t5). Figure 1 In the embodiment of the present invention, the cut-off signal Vcmp is outputted from the cut-off signal output unit 43 as a high output signal. Therefore, the ignition unit 31 is activated to ignite the gunpowder, the cut-off unit 33 is operated, and the cut-off unit 14 is cut off. Therefore, the power line 13 is disconnected, and the power line 13 is cut off, protecting the battery 11 and the relay 15 from the influence of overcurrent.

[0051] The time from when an overcurrent flows through the power line 13 until the current is cut off can be set according to the capacity of the capacitor 42. Therefore, the capacity of the capacitor 42 can be set according to the allowable current of the battery 11 and the relay 15. In addition, the time from when an overcurrent flows through the power line 13 until the current is cut off can be set according to the current value of the constant current circuit 47. Therefore, the current value of the constant current circuit 47 can be set according to the allowable current of the battery 11 and the relay 15.

[0052] As described above, the current interruption device 1 according to the first embodiment uses the Hall element 2 to detect the current value of the power line 13, thereby being able to interrupt the current while suppressing the consumption of the battery 11. In addition, the current interruption device 1 according to the present embodiment charges the capacitor 42 when the current I of the power line 13 becomes equal to or greater than a predetermined current value, and interrupts the power line 13 when the voltage Vc of the capacitor 42 exceeds the threshold value Vref. Therefore, the current interruption device 1 according to the present embodiment can suppress the power line 13 from being interrupted due to an instantaneous overcurrent. Therefore, the current interruption device 1 according to the present embodiment can suppress the consumption of the battery 11 and appropriately interrupt the current I of the power line 13.

[0053] Furthermore, the current interruption device 1 according to the present embodiment can interrupt the current while suppressing consumption of the battery 11 by using the Hall element 2 to detect the current value of the power line 13 . Therefore, when the current interruption device 1 is mounted on a vehicle for use, the cruising distance of the vehicle can be extended.

[0054] In addition, the current interruption device 1 according to the present embodiment includes a constant current circuit 47 for discharging a constant current from the capacitor 42, thereby preventing the capacitor 42 from being instantly charged due to an instantaneous overcurrent. Therefore, the current interruption device 1 according to the present embodiment can appropriately interrupt the current I of the power supply line 13 as needed.

[0055] Next, a current interruption device 1A according to a second embodiment will be described.

[0056] Figure 3 1A is a circuit diagram showing a schematic configuration of a current interruption device 1A according to the second embodiment. The current interruption device 1A according to the present embodiment is different from the current interruption device 1 according to the first embodiment in that a second interruption signal output unit 50 is additionally provided.

[0057] The second cut-off signal output unit 50 is a circuit that outputs a cut-off signal Vcmp2 to the cut-off unit 3 without waiting for the voltage Vc of the capacitor 42 to exceed the threshold value Vref when a large current flows through the power line 13. For example, a comparator is used as the second cut-off signal output unit 50, and the output signal of the amplifier circuit 44 and the output signal of the second constant voltage circuit 51 are input. The second constant voltage circuit 51 sets the threshold value Vref2. Therefore, in a case where the detection signal of the Hall element 2 is amplified and exceeds the threshold value Vref2, even if the voltage Vc of the capacitor 42 does not exceed the threshold value Vref, the second cut-off signal output unit 50 will output the cut-off signal Vcmp2 to the switch element 35 of the cut-off unit 3 to cut off the current I of the power line 13. That is, as Figure 4 As shown, when a large current flows through the power line 13 and the output of the amplifier circuit 44 exceeds the threshold value Vref2 (time t7), the current I of the power line 13 is instantly cut off.

[0058] Thus, the current interruption device 1A according to the present embodiment can prevent the power line 13 from being interrupted due to an instantaneous overcurrent, and can quickly interrupt the current when a large current that may cause trouble to the battery 11 and the relay 15 flows through the power line 13. Therefore, the current interruption device 1A according to the present embodiment can appropriately interrupt the current I of the power line 13, further improving safety.

[0059] Next, a current interruption device 1B according to a third embodiment will be described.

[0060] Figure 5 1B is a circuit diagram showing a schematic configuration of a current interruption device 1B according to a third embodiment. The current interruption device 1B according to this embodiment is different from the current interruption device 1 according to the first embodiment in that a third interruption signal output unit 52 is additionally provided.

[0061] The third cutoff signal output unit 52 is a circuit that outputs a cutoff signal Vcmp3 to the cutoff unit 3 when a large current flows through the power line 13. For example, a comparator is used as the third cutoff signal output unit 52, and the output signal of the amplifier circuit 44 and the output signal of the third constant voltage circuit 53 are input. The third constant voltage circuit 53 sets a threshold value Vref3. The threshold value Vref3 is set to a current value that is the same as the 100% value of the current I of the power line 13 or a current value that is smaller than the 100% value.

[0062] When the detection signal of the Hall element 2 is amplified and exceeds the threshold value Vref3, the third cutoff signal output unit 52 outputs the cutoff signal Vcmp3 as a low output signal to the switch element 36 of the cutoff unit 3. The switch element 36 is provided between the ignition unit 31 and the power supply VB, and the cutoff signal Vcmp3 is output as a low level signal, thereby enabling the ignition unit 31 to start. Furthermore, when the ignition unit 31 is in a state where it can start, and the voltage Vc of the capacitor 42 exceeds the threshold value Vref due to an overcurrent in the power supply line 13, the ignition unit 31 starts, and the current I in the power supply line 13 is cut off. That is, as Figure 6 As shown at time t9 , when the cutoff signal Vcmp3 is output as a low-level signal and the voltage Vc of the capacitor 42 exceeds the threshold value Vref, the current I of the power line 13 is instantly cut off.

[0063] In this way, the current cut-off device 1B involved in this embodiment instantly cuts off the current I of the power line 13 when the cut-off signal Vcmp3 is output as a low-level signal and the voltage Vc of the capacitor 42 exceeds the threshold value Vref, thereby preventing the current I from being mistakenly cut off when the voltage Vc of the capacitor 42 accidentally exceeds the threshold value Vref due to noise, etc. when the current I of the power line 13 is not an overcurrent.

[0064] The current interrupt device according to the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. The current interrupt device according to each embodiment can also be configured by appropriately combining the components of the above-described embodiment and modified example.

[0065] For example, in the second embodiment and the third embodiment, the second cut-off signal output unit 50 and the third cut-off signal output unit 52 share the Hall element 2 and the amplifier circuit 44 with the cut-off signal output unit 43, but a Hall element and an amplifier circuit for the second cut-off signal output unit 50 and the third cut-off signal output unit 52 may be separately provided in addition to the Hall element 2 and the amplifier circuit 44.

[0066] In addition, in each of the above-mentioned embodiments, Figure 1 , Figure 3 as well as Figure 5 The cut-off control unit 4 can be an integrated circuit formed on the same silicon substrate, and the Hall element 2 can also be arranged on the silicon substrate. In addition, the Hall element 2 can also be equipped with a component such as a magnetic core to guide the magnetic field of the current I and keep away from the external magnetic field that is the main cause of the error.

[0067] Furthermore, in each of the above-mentioned embodiments, the current interruption device mounted on a vehicle has been described, but the current interruption device according to the present invention can also be applied to a device not mounted on a vehicle.

Claims

1. A current cut-off device, characterized in that: have: a Hall element that detects a current value of a power line that supplies power from a battery to a load; a cutting unit configured to cut off the power line; as well as a cutoff control unit that operates the cutoff unit to cut off the power line based on a detection signal of the Hall element, The cutoff control unit includes: a voltage-current conversion unit that outputs a current corresponding to an output voltage value of the Hall element; a capacitor charged according to an output current of the voltage-current conversion unit; and a cutoff signal output unit that outputs a cutoff signal to the cutoff unit when the voltage of the capacitor exceeds a threshold value.

2. The current interruption device according to claim 1, characterized in that: The cutoff control unit further includes a constant current circuit that discharges a constant current from the capacitor.

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