Shut-off system and control method

Abstract

This shut-off system (11) for shutting off a power line connecting a battery (12) and a load (17) operated by power from the battery (12) comprises: a current sensor (13) for measuring current flowing through the power line; a first relay (16) provided on the power line; a first active fuse (15) that is connected in series with the first relay (16), and that is capable of shutting off the power line; a current suppression circuit (21) connected in parallel with the first active fuse (15) and having a second active fuse (19) and a second relay (20) connected in series to each other; and a control unit (14). The control unit (14) shuts off the power line by driving the first active fuse (15) when the current value of the current measured by the current sensor (13) is equal to or greater than a first predetermined value.

Description

Isolation system and control method

[0001] The present disclosure relates to an interruption system for interrupting a power line connecting a battery and a load, and a control method thereof.

[0002] Patent document 1 discloses a technology that, when a short-circuit mode failure is detected, cuts off the power line from the main battery to the load and supplies power from the sub-battery to the load, thereby enabling the vehicle to continue evacuation even after a failure.

[0003] JP 2017-28773 A

[0004] However, the technology disclosed in Patent Document 1 requires the provision of a separate sub-battery, which increases the size and cost.

[0005] Therefore, the present disclosure provides a cutoff system that can supply power to a load even after a power line is cut off without providing a sub-battery.

[0006] The interruption system of the present disclosure is an interruption system for interrupting a power line connecting a battery and a load powered by power from the battery, and includes a current sensor that measures the current flowing in the power line, a first relay provided on the power line, a first active fuse connected in series with the first relay and capable of interrupting the power line, a current suppression circuit connected in parallel with the first active fuse and having a second active fuse and a second relay connected in series with each other, and a control unit, wherein the control unit interrupts the power line by driving the first active fuse when the current value of the current measured by the current sensor is equal to or greater than a first predetermined value.

[0007] A control method according to the present disclosure is a control method for a shutoff system for shutting off a power line connecting a battery and a load powered by power from the battery, the shutoff system including a current sensor that measures a current flowing through the power line, a first active fuse that can shut off the power line, and a current suppression circuit that is connected in parallel with the first active fuse and has a second active fuse and a second relay that are connected in series with each other, and the control method shuts off the power line by driving the first active fuse and turns on the second relay when the current value of the current measured by the current sensor is equal to or greater than a first predetermined value.

[0008] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0009] According to the interruption system according to one aspect of the present disclosure, it is possible to supply power to a load even after the power line is interrupted without providing a sub-battery.

[0010] Fig. 1 is a block diagram showing an example of an interruption system according to embodiment 1. Fig. 2 is a flowchart showing an example of the operation of a control unit according to embodiment 1. Fig. 3 is a block diagram showing an example of an interruption system according to embodiment 2. Fig. 4 is a flowchart showing an example of the operation of a control unit according to embodiment 2.

[0011] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0012] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement and connection of the components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0013] (First embodiment) Hereinafter, an interruption system according to a first embodiment will be described.

[0014] FIG. 1 is a block diagram showing an example of an interruption system 11 according to the first embodiment.

[0015] The interruption system 11 is used in a transport device or the like that includes a battery 12 and a load 17. In addition to the interruption system 11, Fig. 1 also shows the battery 12 and the load 17 that are provided in the transport device or the like. The interruption system 11 is used in an electric vehicle such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), or a fuel cell vehicle (FCV), for example.

[0016] The battery 12 is a battery that can apply a high voltage of, for example, several hundred volts to the load 17. For example, the battery 12 is a main battery (for example, a lithium ion battery) in an electric vehicle.

[0017] The load 17 is a load that operates using power from the battery 12, and is, for example, an inverter or a motor of an electric vehicle. The electric vehicle is propelled by power supplied from the battery 12 to the load 17. In the event of an accident or the like, a large current may flow due to a short circuit in the power line connecting the battery 12 and the load 17, which may cause the battery 12 to smoke or catch fire, and therefore the interruption system 11 is used in transportation equipment.

[0018] The interruption system 11 is a system for interrupting a power line connecting the battery 12 and the load 17 in the event of an abnormality, and is provided between the battery 12 and the load 17. The power line connecting the battery 12 and the load 17 includes a positive power line connecting the positive terminal of the battery 12 and the positive terminal of the load 17, and a negative power line connecting the negative terminal of the battery 12 and the negative terminal of the load 17. The interruption system 11, for example, interrupts the positive power line in the event of an abnormality.

[0019] The interruption system 11 includes a current sensor 13, a control unit 14, a first active fuse 15, a first relay 16, and a current suppression circuit 21. Note that active fuses such as the first active fuse 15 and a second active fuse 19 (described later) are devices that are interrupted by a signal from outside the active fuse, and examples thereof include pyro-fuses, pyro-switches, and pyrotechnic interruption devices. Furthermore, this embodiment does not exclude the use of active switches as active fuses.

[0020] Current sensor 13 is a sensor that measures the current flowing through the power line. For example, current sensor 13 is a shunt-type sensor (e.g., a shunt resistor) or a sensor such as a Hall element. Current sensor 13 outputs the measurement result (current value) to control unit 14. While FIG. 1 shows an example in which current sensor 13 is provided on the positive power line, it may also be provided on the negative power line.

[0021] For example, if the current sensor 13 is a shunt-type sensor, the current sensor 13 is provided on the negative power line. If the current sensor 13 is a shunt-type sensor and provided on the positive power line, a high voltage may be applied between the current sensor 13 and the reference potential of the control unit 14, to which the measurement result of the current sensor 13 is output. This is because the reference potential of the control unit 14 is often set to the potential of the negative terminal of the battery 12. In other words, a high voltage is applied to the current sensor 13, and the control unit 14 connected to the current sensor 13 is also affected. Therefore, if the current sensor 13 is a shunt-type sensor, providing the current sensor 13 on the negative power line can prevent a high voltage from being applied to the control unit 14.

[0022] However, if current sensor 13 is a non-contact type sensor such as a Hall element, providing current sensor 13 on the positive power line is unlikely to pose a problem because high voltage is not applied to current sensor 13 itself and control unit 14 is not affected. For this reason, if current sensor 13 is a non-contact type sensor such as a Hall element, current sensor 13 may be provided on the positive power line as shown in FIG.

[0023] The first relay 16 is provided on the power line. For example, as shown in FIG. 1 , the first relay 16 is provided on the positive power line. The first relay 16 is controlled by, for example, the control unit 14 to switch between conduction and non-conduction between the positive terminal of the battery 12 and the positive terminal of the load 17 via the positive power line. In other words, the first relay 16 switches between interrupting and releasing the interruption of the power line. In FIG. 1 , the signal line from the control unit 14 to the first relay 16 is not shown. Note that the first relay 16 does not have to be controlled by the control unit 14, and may be controlled by an ECU (Electronic Control Unit) or the like.

[0024] The first active fuse 15 is a pyro-fuse connected in series with the first relay 16 and capable of interrupting the power line. Pyro-fuses are also called pyro-switches, pyrotechnic switches, or pyroelectric switches. For example, the first active fuse 15 is provided on the positive power line. The first active fuse 15 interrupts the power line when a large current flows through the power line due to a short circuit. The pyro-fuse used in the first active fuse 15 (first pyro-fuse) contains explosives and ignites the explosives based on an external interruption command signal. The explosives ignite the explosives, irreversibly interrupting the power line and causing the power line to be interrupted. The first active fuse 15 interrupts the power line upon receiving an external interruption command signal (controller 14 in FIG. 1 ).

[0025] The current suppression circuit 21 is connected in parallel with the first active fuse 15 and has a second active fuse 19 and a second relay 20 connected in series with each other. The current suppression circuit 21 also has a resistor 18 connected in series with the second active fuse 19 and the second relay 20.

[0026] The second relay 20 is provided on a bypass line that bypasses the first active fuse 15. The second relay 20 is controlled by the control unit 14 to switch between conduction and non-conduction between the positive terminal of the battery 12 and the positive terminal of the load 17 via the bypass line. In other words, the second relay 20 switches between interrupting the bypass line and releasing the interruption.

[0027] The second active fuse 19 is a pyroelectric fuse connected in series with the second relay 20 and capable of cutting off the bypass line. The second active fuse 19 is provided on the bypass line. The second active fuse 19 cuts off the bypass line when a large current flows through the power line passing through the bypass line. The pyroelectric fuse used in the second active fuse 19 (second pyroelectric fuse) contains an explosive and ignites the explosive based on a cutoff instruction signal from outside the second pyroelectric fuse, thereby irreversibly cutting off the bypass line with the explosive force generated by the ignition of the explosive. The second active fuse 19 cuts off the bypass line upon receiving a cutoff instruction signal from outside (the control unit 14 in FIG. 1 ).

[0028] The resistor 18 is connected in series with the second relay 20 and the second active fuse 19 and is provided on the bypass line. The resistor 18 is a current limiting resistor for limiting the current flowing through the power line via the bypass line. The resistance value of the resistor 18 is set depending on the application of the interrupter system 11, but is, for example, several ohms to several tens of ohms.

[0029] The control unit 14 controls the first active fuse 15, the second active fuse 19, and the second relay 20. The control unit 14 may also control the first relay 16. The control unit 14 is a computer including a processor (microprocessor) and a memory. The memory may be a read-only memory (ROM) or a random access memory (RAM), and may store programs executed by the processor. FIG. 1 shows one control unit 14, and the first active fuse 15, the second active fuse 19, the first relay 16, and the second relay 20 are controlled by the single control unit 14, but this is not limiting. For example, the components of the control unit 14 that control the first active fuse 15, the second active fuse 19, the first relay 16, and the second relay 20 may be provided separately.

[0030] Here, the operation of the control unit 14 will be described with reference to FIG.

[0031] Fig. 2 is a flowchart showing an example of the operation of the control unit 14 according to embodiment 1. The process shown in Fig. 2 is repeated.

[0032] The control unit 14 determines whether the current value measured by the current sensor 13 is equal to or greater than a first predetermined value and whether the first active fuse 15 has been driven (step S101). The first predetermined value is, for example, the rated current value of the first relay 16, which is a current value at which the first relay 16 may fail.

[0033] When the control unit 14 determines that the first active fuse 15 is not yet actuated and that the current value measured by the current sensor 13 is equal to or greater than the first predetermined value (Yes in step S101), the control unit 14 actuates the first active fuse 15 to cut off the power line (step S102), thereby preventing the first relay 16 from failing.

[0034] Next, the control unit 14 turns on the second relay 20 (step S103). This allows current to flow through the power line via the bypass line. The resistor 18 provided in the bypass line can suppress the current flowing through the power line.

[0035] If the control unit 14 determines that the current value measured by the current sensor 13 is less than the first predetermined value (No in step S101), it determines whether the first active fuse 15 has been actuated (step S104). If the control unit 14 determines that the first active fuse 15 has not been actuated (No in step S104), it ends the processing. If the first active fuse 15 has not been actuated, the power line is in a normal state, where no abnormal current greater than or equal to the first predetermined value is flowing. The processing from step S101 is repeated to continue monitoring whether or not an abnormal current greater than or equal to the first predetermined value is flowing through the power line.

[0036] When the control unit 14 determines that the first active fuse 15 has been driven (Yes in step S104), it determines whether the current value measured by the current sensor 13 is equal to or greater than a second predetermined value (step S105). The second predetermined value is, for example, a current value corresponding to the rated power of the resistor 18, the rated current value of the first relay 16, or the rated current value of the second relay 20, and is a current value at which the resistor 18, the first relay 16, or the second relay 20 may fail.

[0037] When the control unit 14 determines that the current value measured by the current sensor 13 is equal to or greater than the second predetermined value (Yes in step S105), the control unit 14 activates the second active fuse 19 to cut off the bypass line (step S106), thereby preventing the first relay 16, the second relay 20, or the resistor 18 from failing.

[0038] In this way, when the current value measured by current sensor 13 is equal to or greater than the first predetermined value, control unit 14 activates first active fuse 15 and turns on second relay 20, and thereafter, when the measured current value is equal to or greater than the second predetermined value, control unit 14 activates second active fuse 19. Even if the current is suppressed by resistor 18 included in current suppression circuit 21, there may be cases where a large current flows that exceeds, for example, the current value corresponding to the rated power of resistor 18 or the rated current value of first relay 16. In this case, second active fuse 19 can cut off the bypass line that supplies power to load 17 via current suppression circuit 21, thereby preventing smoke or fire from occurring in battery 12.

[0039] When the control unit 14 determines that the current value measured by the current sensor 13 is less than the second predetermined value (No in step S105), the control unit 14 determines whether the current value is equal to or greater than a third predetermined value (step S107). The third predetermined value is, for example, a current value of an abnormal current at which the power supply from the battery 12 to the load 17 should be stopped and which can be interrupted by the second relay 20.

[0040] When the control unit 14 determines that the current value measured by the current sensor 13 is equal to or greater than the third predetermined value (Yes in step S107), it turns off the second relay 20 (step S108). This allows the second relay 20 to interrupt a relatively large abnormal current without driving the second active fuse 19.

[0041] In this way, when the current value measured by the current sensor 13 is equal to or greater than the first predetermined value, the control unit 14 activates the first active fuse 15 and turns on the second relay 20. Thereafter, when the measured current value is equal to or greater than a third predetermined value that is smaller than the second predetermined value but less than the second predetermined value, the control unit 14 turns off the second relay 20. Even if the current is suppressed by the resistor 18 included in the current suppression circuit 21, there may be a case where a relatively large abnormal current flows, for example, a current that does not exceed the rated current value of the second relay 20. In this case, the bypass line supplying power to the load 17 via the current suppression circuit 21 can be cut off by the second relay 20, which can reversibly cut off and release the cutoff, without activating the second active fuse 19, which cannot reversibly cut off and release the cutoff, thereby preventing smoke or fire from the battery 12.

[0042] If the control unit 14 determines that the current value measured by the current sensor 13 is less than the third predetermined value (No in step S107), the control unit 14 ends the process. If the measured current value is less than the third predetermined value, the current flowing through the power line is sufficiently suppressed. The process from step S101 is repeated to continue monitoring whether a current equal to or greater than the third predetermined value flows through the power line.

[0043] As described above, even after the power line is interrupted by the first active fuse 15, power can be supplied to the load 17 via the current suppression circuit 21 connected in parallel with the first active fuse 15. Therefore, power can be supplied to the load 17 even after the power line is interrupted without providing a sub-battery. For example, even after the power line is interrupted by the first active fuse 15, it is possible to evacuate the transportation equipment. Although a large current may flow if a short-circuit fault occurs in the load 17, the current suppression circuit 21 includes the resistor 18, thereby suppressing the current. Furthermore, if the current cannot be suppressed sufficiently even by the resistor 18 included in the current suppression circuit 21 and a large current is flowing, the bypass line for supplying power to the load 17 via the current suppression circuit 21 can be interrupted by the second active fuse 19 or the second relay 20, thereby preventing the battery 12 from emitting smoke or catching fire.

[0044] Second Embodiment Next, a shutdown system according to a second embodiment will be described.

[0045] FIG. 3 is a block diagram showing an example of an interruption system 11a according to the second embodiment.

[0046] The interruption system 11a according to the second embodiment differs from the interruption system 11 according to the first embodiment in that it includes a control unit 14a instead of the control unit 14, and further includes a precharge circuit 200. Since the other points are the same as those in the first embodiment, a description thereof will be omitted, and the following description will focus on the points of difference.

[0047] The precharge circuit 200 is connected in parallel with the first relay 16 and has a precharge resistor 202 and a precharge relay 201 connected in series with each other. The precharge relay 201 and the precharge resistor 202 are connected in series. For example, when starting up the transportation equipment, the first relay 16 is turned off and the precharge relay 201 is turned on. This allows current to flow to the load 17 via the precharge resistor 202, thereby suppressing the occurrence of inrush current. The resistance value of the precharge resistor 202 is set depending on the application of the interruption system 11a, and is, for example, several ohms to several tens of ohms.

[0048] The control unit 14a controls the first active fuse 15, the second active fuse 19, the first relay 16, the second relay 20, and the precharge relay 201. The control unit 14a is a computer including a processor (microprocessor) and memory. The memory may be a ROM or RAM, and may store programs executed by the processor. Note that FIG. 3 shows one control unit 14a, and the first active fuse 15, the second active fuse 19, the first relay 16, the second relay 20, and the precharge relay 201 are controlled by the single control unit 14a. However, this is not limiting. For example, the components of the control unit 14a that control the first active fuse 15, the second active fuse 19, the first relay 16, the second relay 20, and the precharge relay 201 may be provided separately.

[0049] Here, the operation of the control unit 14a will be described with reference to FIG.

[0050] Fig. 4 is a flowchart showing an example of the operation of the control unit 14a according to embodiment 2. The process shown in Fig. 4 is repeated.

[0051] The control unit 14a determines whether the current value measured by the current sensor 13 is equal to or greater than a first predetermined value and whether the first active fuse 15 has been driven (step S201). The first predetermined value is, for example, the rated current value of the first relay 16, which is a current value at which the first relay 16 may fail.

[0052] When the control unit 14a determines that the first active fuse 15 is not yet actuated and that the current value measured by the current sensor 13 is equal to or greater than the first predetermined value (Yes in step S201), the control unit 14a actuates the first active fuse 15 to interrupt the power line (step S202), thereby preventing the first relay 16 from failing.

[0053] Next, the control unit 14a turns off the first relay 16 (step S203), turns on the precharge relay 201 (step S204), and turns on the second relay 20 (step S205). This allows current to flow through the power line via the current suppression circuit 21 and the precharge circuit 200. The current suppression circuit 21 and the precharge circuit 200 are provided with the resistor 18 and the precharge resistor 202, so that the current flowing through the power line can be suppressed.

[0054] If the control unit 14a determines that the current value measured by the current sensor 13 is less than the first predetermined value (No in step S201), it determines whether the first active fuse 15 has been actuated (step S206). If the control unit 14a determines that the first active fuse 15 has not been actuated (No in step S206), it ends the process. If the first active fuse 15 has not been actuated, the power line is in a normal state, where no abnormal current greater than or equal to the first predetermined value is flowing. The process from step S201 is repeated to continue monitoring whether or not an abnormal current greater than or equal to the first predetermined value is flowing through the power line.

[0055] When the control unit 14a determines that the first active fuse 15 has been driven (Yes in step S206), the control unit 14a determines whether the current value measured by the current sensor 13 is equal to or greater than a second predetermined value (step S207). The second predetermined value is, for example, a current value corresponding to the rated power of the resistor 18 or a rated current value of the second relay 20, which is a current value at which the resistor 18 or the second relay 20 may fail.

[0056] When the control unit 14a determines that the current value measured by the current sensor 13 is equal to or greater than the second predetermined value (Yes in step S207), the control unit 14a activates the second active fuse 19 to cut off the bypass line (step S208), thereby preventing the second relay 20 or the resistor 18 from failing.

[0057] In this way, when the current value measured by current sensor 13 is equal to or greater than the first predetermined value, control unit 14a activates first active fuse 15, turns off first relay 16, turns on precharge relay 201, and turns on second relay 20. Thereafter, when the measured current value is equal to or greater than the second predetermined value, control unit 14a activates second active fuse 19. Even if the current is suppressed by resistor 18 in current suppression circuit 21 and precharge resistor 202 in precharge circuit 200, there may be cases where a large current flows that exceeds, for example, the current value corresponding to the rated power of resistor 18. In this case, second active fuse 19 can cut off the bypass line that supplies power to load 17 via current suppression circuit 21, thereby preventing smoke or fire from occurring in battery 12.

[0058] When the control unit 14a determines that the current value measured by the current sensor 13 is less than the second predetermined value (No in step S207), the control unit 14a determines whether the current value is equal to or greater than a third predetermined value (step S209). The third predetermined value is, for example, a current value of an abnormal current at which the power supply from the battery 12 to the load 17 should be stopped and which can be interrupted by the second relay 20.

[0059] When the control unit 14a determines that the current value measured by the current sensor 13 is equal to or greater than the third predetermined value (Yes in step S209), it turns off the second relay 20 (step S210). This allows the second relay 20 to interrupt a relatively large abnormal current without driving the second active fuse 19.

[0060] In this manner, when the current value measured by current sensor 13 is equal to or greater than the first predetermined value, control unit 14a activates first active fuse 15, turns off first relay 16, turns on precharge relay 201, and turns on second relay 20. Thereafter, when the measured current value is equal to or greater than a third predetermined value that is smaller than the second predetermined value but less than the second predetermined value, control unit 14a turns off second relay 20. Even if the current is suppressed by resistor 18 of current suppression circuit 21, there may be a case where a relatively large abnormal current flows but does not exceed the rated current value of second relay 20. In this case, the bypass line supplying power to load 17 via current suppression circuit 21 can be interrupted by second relay 20, which can reversibly interrupt and release the interruption, without activating second active fuse 19, which cannot reversibly interrupt and release the interruption, thereby preventing smoke or fire from battery 12.

[0061] If the control unit 14a determines that the current value measured by the current sensor 13 is less than the third predetermined value (No in step S209), it determines whether the current value is less than a fourth predetermined value (step S211). The fourth predetermined value is a current value such that the current value measured when the precharge resistor 202 is not present, i.e., when the precharge relay 201 is turned off, is the current value corresponding to the rated power of the resistor 18, the rated current value of the first relay 16, or the rated current value of the second relay 20. That is, the control unit 14a determines whether the current value is small enough to be equal to or greater than the second predetermined value but not equal to or greater than the third predetermined value, even when the precharge relay 201 is turned off. For example, because the amount of current fluctuation due to the presence or absence of the precharge resistor 202 can be estimated based on the resistance value of the precharge resistor 202, the fourth predetermined value is set according to the resistance value of the precharge resistor 202.

[0062] When the control unit 14a determines that the current value measured by the current sensor 13 is less than the fourth predetermined value (Yes in step S211), it turns on the first relay 16 (step S212) and turns off the precharge relay 201 (step S213). As a result, the current flows through the power line without passing through the precharge circuit 200, and the current supplied to the load 17 increases.

[0063] In this way, when the current value measured by current sensor 13 is equal to or greater than the first predetermined value, control unit 14a drives first active fuse 15, turns off first relay 16, turns on precharge relay 201, and turns on second relay 20. Thereafter, when the measured current value is less than a fourth predetermined value that is smaller than the second and third predetermined values, control unit 14a turns on first relay 16 and turns off precharge relay 201. When the current is suppressed by resistor 18 in current suppression circuit 21 and precharge resistor 202 in precharge circuit 200, the current can be suppressed significantly. Even without suppressing the current by precharge resistor 202, the current can be suppressed by resistor 18 alone unless a large current that exceeds the current value corresponding to the rated power of resistor 18, the rated current value of first relay 16, or the rated current value of second relay 20 flows. This makes it possible to prevent the current supplied to the load 17 from becoming too small, and to prevent the load 17 from becoming uncontrollable.

[0064] When the control unit 14a determines that the current value measured by the current sensor 13 is equal to or greater than the fourth predetermined value (No in step S211), it does not turn on the first relay 16 and does not turn off the pre-charge relay 201. This is because if the current value measured by the current sensor 13 is equal to or greater than the fourth predetermined value and the first relay 16 is turned on and the pre-charge relay 201 is turned off, the current value may become equal to or greater than the second predetermined value or the third predetermined value, which may cause a malfunction of the resistor 18, the first relay 16, or the second relay 20. Then, the control unit 14a ends the processing and repeats the processing from step S201.

[0065] After the first relay 16 is turned on in step S212 and the pre-charge relay 201 is turned off in step S213, if the current value measured by the current sensor 13 in step S211 becomes equal to or greater than the fourth predetermined value (No in step S211), the pre-charge relay 201 is turned on (step S214) and the first relay 16 is turned off (step S215). This allows the current to be suppressed again by the pre-charge resistor 202.

[0066] Note that the control unit 14a may first turn on the second relay 20 after driving the first active fuse 15, and if the current value measured by the current sensor 13 in that state is equal to or greater than the second predetermined value, turn off the first relay 16 and turn on the pre-charge relay 201. In other words, the control unit 14a may first check whether the current is sufficiently suppressed by the resistor 18 alone, and if it is not sufficiently suppressed, turn on the pre-charge relay 201 and turn off the first relay 16 so that the measured current value becomes less than the second predetermined value.

[0067] In this way, when the current value measured by current sensor 13 is equal to or greater than the first predetermined value, control unit 14a activates first active fuse 15 and controls first relay 16, second relay 20, and precharge relay 201 so that the current value measured by current sensor 13 becomes less than the second predetermined value. This allows current suppression to be achieved using precharge resistor 202 used to precharge the load capacitance in addition to resistor 18 included in current suppression circuit 21, thereby distributing power consumption and heat generation. This enables the current suppression circuit 21 to be made smaller and less expensive.

[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 was described in which the current suppression circuit 21 has a resistor 18, but the current suppression circuit 21 does not have to have a resistor 18, and may be equipped with an element that suppresses current other than the resistor 18.

[0070] For example, the present disclosure can be realized not only as an interruption system, but also as a control method including steps (processing) performed by components (e.g., a control unit) that make up the interruption system.

[0071] The control method is a control method for a disconnection system for interrupting a power line connecting a battery and a load powered by power from the battery, the disconnection system comprising: a current sensor 13 for measuring a current flowing in the power line; a first active fuse 15 capable of interrupting the power line; and a current suppression circuit 21 connected in parallel with the first active fuse 15 and having a second active fuse 19 and a second relay 20 connected in series with each other. As shown in FIG. 2 , when the current value measured by the current sensor 13 is equal to or greater than a first predetermined value (Yes in step S101), the control method activates the first active fuse 15 to interrupt the power line (step S102) and turns on the second relay 20 (step S103).

[0072] For example, the present disclosure can be realized as a program for causing a computer (processor) to execute steps included in the control method. 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.

[0073] 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.

[0074] In the above-described embodiment, each component included in the shutdown system may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0075] Some or all of the functions of the shutdown system according to the above-described embodiments are typically realized as an LSI, which is an integrated circuit. These may be individually implemented as single chips, or may be integrated into a single chip that includes some or all of the functions. Furthermore, the integrated circuit is not limited to an LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within an LSI, may also be used.

[0076] Furthermore, if an integrated circuit technology that can replace LSIs emerges due to advances in semiconductor technology or other derivative technologies, it is natural that each component included in the shutdown system may be integrated using that technology.

[0077] 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 that does not deviate from the intent of this disclosure.

[0078] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0079] (Technology 1) A shutoff system for shutting off a power line connecting a battery and a load powered by power from the battery, the shutoff system comprising: a current sensor that measures a current flowing in the power line; a first relay provided on the power line; a first active fuse connected in series with the first relay and capable of shutting off the power line; a current suppression circuit connected in parallel with the first active fuse and having a second active fuse and a second relay connected in series with each other; and a control unit, wherein the control unit shuts off the power line by driving the first active fuse when the current value of the current measured by the current sensor is equal to or greater than a first predetermined value.

[0080] According to this, even after the power line is interrupted by the first active fuse, power can be supplied to the load via the current suppression circuit connected in parallel with the first active fuse. Therefore, power can be supplied to the load even after the power line is interrupted without a sub-battery. For example, even after the power line is interrupted by the first active fuse, it is possible to evacuate the vehicle. Furthermore, if a short-circuit fault occurs in the load, a large current may flow, but the current suppression circuit can suppress the current. Furthermore, if the current suppression circuit cannot fully suppress the current and a large current flows, the bypass line supplying power to the load via the current suppression circuit can be interrupted by the second active fuse or the second relay, thereby preventing the battery from smoking or catching fire.

[0081] (Technology 2) The interruption system described in Technology 1, wherein the control unit activates the first active fuse and turns on the second relay when the current value is equal to or greater than the first predetermined value, and then activates the second active fuse when the current value is equal to or greater than a second predetermined value.

[0082] Even if the current is suppressed by the current suppression circuit, there may be cases where a large current flows that exceeds, for example, the current value corresponding to the rated power of the element that suppresses the current of the current suppression circuit or the rated current value of the first relay. In this case, the bypass line that supplies power to the load via the current suppression circuit can be cut off by the second active fuse, thereby preventing the battery from smoking or catching fire.

[0083] (Technology 3) In the circuit breaking system described in Technology 2, when the current value is equal to or greater than the first predetermined value, the control unit drives the first active fuse and turns on the second relay, and thereafter, when the current value is equal to or greater than a third predetermined value that is smaller than the second predetermined value and is less than the second predetermined value, the control unit turns off the second relay.

[0084] Even if the current is suppressed by the current suppression circuit, there may be a case where a relatively large abnormal current flows, but the current does not exceed the rated current value of the second relay. In this case, the bypass line that supplies power to the load via the current suppression circuit can be cut off by the second relay, which can reversibly cut off and release the cutoff, without driving the second active fuse, which cannot reversibly cut off and release the cutoff, thereby preventing the battery from smoking or catching fire.

[0085] (Technology 4) The interruption system according to Technology 1 further includes a precharge circuit connected in parallel with the first relay and having a precharge resistor and a precharge relay connected in series with each other, wherein the control unit activates the first active fuse when the current value is equal to or greater than the first predetermined value, and controls the first relay, the second relay, and the precharge relay so that the current value is less than a second predetermined value.

[0086] This allows current to be suppressed by utilizing the precharge resistor used to precharge the load capacitance in addition to the current suppression circuit, which distributes power consumption and heat generation, thereby enabling the current suppression circuit to be made smaller and less expensive.

[0087] (Technology 5) In a circuit breaking system according to Technology 4, when the current value is equal to or greater than the first predetermined value, the control unit activates the first active fuse, turns off the first relay, turns on the precharge relay, and turns on the second relay, and then, when the current value is equal to or greater than the second predetermined value, activates the second active fuse.

[0088] Even if the current is suppressed by the precharge resistor of the current suppression circuit and the precharge circuit, there may be cases where a large current flows that exceeds the current value corresponding to the rated power of the element that suppresses the current of the current suppression circuit. In such cases, the bypass line that supplies power to the load via the current suppression circuit can be cut off by the second active fuse, thereby preventing the battery from emitting smoke or catching fire.

[0089] (Technology 6) The interruption system described in Technology 5, wherein the control unit, when the current value is equal to or greater than the first predetermined value, drives the first active fuse, turns off the first relay, turns on the precharge relay, and turns on the second relay, and then, when the current value is equal to or greater than a third predetermined value that is smaller than the second predetermined value and is less than the second predetermined value, turns off the second relay.

[0090] Even if the current is suppressed by the precharge resistor of the current suppression circuit and the precharge circuit, there may be cases where a current that does not exceed the rated current value of the second relay still flows. In this case, the power line that supplies power to the load via the current suppression circuit can be cut off by the second relay, which can reversibly cut off and release the cutoff, without driving the second active fuse, which cannot reversibly cut off and release the cutoff, thereby preventing the battery from smoking or catching fire.

[0091] (Technology 7) In a circuit breaking system described in Technology 5 or 6, when the current value is equal to or greater than the first predetermined value, the control unit drives the first active fuse, turns off the first relay, turns on the pre-charge relay, and turns on the second relay, and then, when the current value is less than a fourth predetermined value that is smaller than the second predetermined value, turns on the first relay and turns off the pre-charge relay.

[0092] When the current is suppressed by the precharge resistor of the current suppression circuit and the precharge circuit, the current can be suppressed significantly, and even if the current is not suppressed by the precharge resistor, the current can be suppressed by the resistor alone unless a large current corresponding to the rated power of the element suppressing the current of the current suppression circuit or exceeding the rated current of the first relay flows. This prevents the current supplied to the load from becoming too small, and prevents the load from becoming uncontrollable.

[0093] (Technology 8) A shutdown system according to any one of technologies 1 to 7, wherein the first active fuse and the second active fuse are pyro fuses.

[0094] Thus, the active fuse may be a pyro fuse.

[0095] (Technology 9) An interruption system described in any one of technologies 1 to 8, wherein the current suppression circuit has a resistor connected in series with the second active fuse and the second relay.

[0096] According to this, the current can be suppressed by the resistor included in the current suppression circuit.

[0097] (Technology 10) A control method for a shutoff system for shutting off a power line connecting a battery and a load powered by power from the battery, the shutoff system including a current sensor that measures a current flowing through the power line, a first active fuse that can shut off the power line, and a current suppression circuit that is connected in parallel with the first active fuse and has a second active fuse and a second relay that are connected in series with each other, the control method driving the first active fuse to shut off the power line and turning on the second relay when a current value of the current measured by the current sensor is equal to or greater than a first predetermined value.

[0098] This makes it possible to provide a control method that can supply power to a load even after the power line is cut off, without providing a sub-battery.

[0099] The present disclosure is applicable to systems that use pyrofuses to cut off power lines, and the like.

[0100] 11, 11a Breaking system 12 Battery 13 Current sensor 14, 14a Control unit 15 First active fuse 16 First relay 17 Load 18 Resistor 19 Second active fuse 20 Second relay 21 Current suppression circuit 200 Precharge circuit 201 Precharge relay 202 Precharge resistor

Claims

1. A shutoff system for shutting off a power line connecting a battery and a load powered by power from the battery, comprising: a current sensor that measures a current flowing in the power line; a first relay provided on the power line; a first active fuse connected in series with the first relay and capable of shutting off the power line; a current suppression circuit connected in parallel with the first active fuse and having a second active fuse and a second relay connected in series with each other; and a control unit, wherein the control unit shuts off the power line by activating the first active fuse when the current value measured by the current sensor is equal to or greater than a first predetermined value.

2. The interruption system according to claim 1, wherein the control unit activates the first active fuse and turns on the second relay when the current value is equal to or greater than the first predetermined value, and then activates the second active fuse when the current value is equal to or greater than a second predetermined value.

3. The interruption system according to claim 2, wherein the control unit drives the first active fuse and turns on the second relay when the current value is equal to or greater than the first predetermined value, and then turns off the second relay when the current value is equal to or greater than a third predetermined value that is smaller than the second predetermined value and is less than the second predetermined value.

4. The interruption system according to claim 1, further comprising a precharge circuit connected in parallel with the first relay and having a precharge resistor and a precharge relay connected in series with each other, wherein the control unit activates the first active fuse when the current value is equal to or greater than the first predetermined value, and controls the first relay, the second relay, and the precharge relay so that the current value becomes less than a second predetermined value.

5. The interruption system according to claim 4, wherein the control unit, when the current value is equal to or greater than the first predetermined value, activates the first active fuse, turns off the first relay, turns on the precharge relay, and turns on the second relay, and thereafter, when the current value is equal to or greater than the second predetermined value, activates the second active fuse.

6. The interruption system according to claim 5, wherein the control unit, when the current value is equal to or greater than the first predetermined value, activates the first active fuse, turns off the first relay, turns on the precharge relay, and turns on the second relay, and thereafter, when the current value is equal to or greater than a third predetermined value that is smaller than the second predetermined value and is less than the second predetermined value, turns off the second relay.

7. The interruption system according to claim 5 or 6, wherein the control unit, when the current value is equal to or greater than the first predetermined value, drives the first active fuse, turns off the first relay, turns on the pre-charge relay, and turns on the second relay, and thereafter, when the current value is less than a fourth predetermined value that is smaller than the second predetermined value, turns on the first relay and turns off the pre-charge relay.

8. The interruption system according to any one of claims 1 to 7, wherein the first active fuse and the second active fuse are pyro fuses.

9. The interruption system according to any one of claims 1 to 8, wherein the current suppression circuit has a resistor connected in series with the second active fuse and the second relay.

10. A control method for a shutoff system for shutting off a power line connecting a battery and a load powered by power from the battery, the shutoff system comprising: a current sensor for measuring a current flowing in the power line; a first active fuse capable of shutting off the power line; and a current suppression circuit connected in parallel with the first active fuse and having a second active fuse and a second relay connected in series with each other, the control method comprising: when a current value of the current measured by the current sensor is equal to or greater than a first predetermined value, driving the first active fuse to shut off the power line and turning on the second relay.

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