Current circuit shut-off system and current circuit shut-off method

Abstract

Disclosed is a current circuit shut-off system that makes it possible to reduce the shut-off performance required of main relays and a fuse and to lower the cost and reduce the size of the main relays, the fuse, and the system as a whole.　A current circuit shut-off system 10 comprises: a current circuit 14 that includes power supply lines 22a, 22b, main relays 24a, 24b that are respectively connected to the power supply lines 22a, 22b, and a fuse 26 and an insulating shut-off device 28 that are connected to one of the power supply lines 22b; and a control unit 30 that transmits ON / OFF signals to the insulating shut-off device 28. In an ON state, the insulating shut-off device 30 keeps the power supply lines 22a, 22b in an energized state. Upon detecting activation of abnormal shut-off that includes shut-off of the main relays 24a, 24b or the fuse 26, the control unit 30 transmits an OFF signal to the insulating shut-off device 28 to shut off the insulating shut-off device 28.

Description

Current Circuit Interruption System and Current Circuit Interruption Method

[0001] The present disclosure relates to a current circuit interruption system and a current circuit interruption method.

[0002] Conventionally, vehicles equipped with a battery composed of a high-voltage secondary battery such as an electric vehicle or a hybrid vehicle have a current circuit interruption system including a relay. For example, in Patent Document 1, a main relay that interrupts the power supply of a battery to a motor or a generator connected via an inverter as a load on the vehicle side, and a fuse that disconnects the battery by fusing when a large current short circuit occurs near the battery during a vehicle abnormality or the like are provided. A current circuit interruption system is shown. Such a main relay used in such a current circuit is provided on the positive electrode side and the negative electrode side, and by turning off the main relay, the power supply from the battery can be stopped.

[0003] Japanese Patent Application Laid-Open No. 2022-30107

[0004] In such a conventional current circuit interruption system, when interrupting a large current from the battery by the main relay or the fuse during a vehicle abnormality, since the current value and voltage value of the battery are large, the damage applied to the main relay and the fuse also increases, and it is inevitable that the insulation performance of the main relay and the fuse after interruption deteriorates. Therefore, in the conventional current circuit interruption system, it is necessary to adopt a main relay and a fuse having high insulation performance, and the size increase and cost increase of each device and the entire current circuit interruption system cannot be avoided.

[0005] Therefore, a current circuit interruption system and a current circuit interruption method are disclosed that can reduce the insulation performance required for the main relay and the fuse, and can reduce the cost and size of the main relay, the fuse, and the entire system.

[0006] The current circuit interruption system of the present disclosure comprises a current circuit including a pair of power lines connecting a battery and a load, a pair of main relays connected to each of the pair of power lines, a fuse and an isolation interruption device connected to either of the power lines, and a control unit that sends an ON / OFF signal to the isolation interruption device of the current circuit, wherein the isolation interruption device maintains the energized state of the power line when it is ON, and the control unit transmits an OFF signal to the isolation interruption device to interrupt it when it detects the activation of an abnormal interruption, including the interruption of the main relay or the fuse.

[0007] The current circuit interruption method of the present disclosure is a current circuit interruption method performed using a current circuit interruption system comprising: a pair of power lines connecting a battery and a load; a pair of main relays connected to each of the pair of power lines; a fuse and an isolation interruption device connected to either of the power lines; and a control unit that sends an ON / OFF signal to the isolation interruption device of the current circuit, wherein the isolation interruption device maintains the energized state of the power lines in the ON state, and the method includes the step of transmitting an OFF signal to the isolation interruption device to interrupt the isolation interruption device when the control unit detects the activation of an abnormal interruption, including the interruption of the main relay or the fuse.

[0008] According to the current circuit interruption system and current circuit interruption method of this disclosure, the required insulation performance of the main relay and fuse can be reduced, and the cost and size of the main relay, fuse, and even the entire system can be reduced.

[0009] Figure 1 is a schematic diagram showing the electrical configuration of the current circuit interruption system according to Embodiment 1. Figure 2 is an explanatory diagram for explaining the circuit interruption operation in the current circuit interruption system shown in Figure 1.

[0010] <Description of Embodiments of the Disclosure> First, embodiments of the Disclosure will be listed and described. The current circuit interruption system of the Disclosure comprises: (1) a current circuit including a pair of power lines connecting a battery and a load, a pair of main relays connected to each of the pair of power lines, and a fuse and an isolation interruption device connected to either of the power lines; and a control unit that sends an ON / OFF signal to the isolation interruption device of the current circuit, wherein the isolation interruption device maintains the energized state of the power lines when in the ON state, and the control unit transmits an OFF signal to the isolation interruption device to interrupt the isolation interruption device when it detects the activation of an abnormal interruption, including the interruption of the main relay or the fuse.

[0011] The current circuit interruption system of this disclosure comprises a current circuit in which a fuse and an insulating interruption device are connected to either of a pair of power lines (a positive power line and a negative power line), each connected to a main relay, and a control unit that sends an ON / OFF signal to the insulating interruption device, which maintains the energized state of the power line when it is ON. The control unit is configured to send an OFF signal to the insulating interruption device when it detects the activation of an abnormal interruption, including the tripping of the main relay or fuse, thereby shutting down the insulating interruption device. As a result, in the event of a vehicle malfunction, if an abnormal interruption such as the tripping of the main relay or fuse is activated, the power line can be quickly shut off by the insulating interruption device, stopping the power supply from the battery to the power line. Consequently, even if the insulation performance of the main relay or fuse has deteriorated due to damage during the tripping, the separately provided insulating interruption device can reliably establish insulation between the battery and the power line. Therefore, the insulation performance required of the main relay and fuse can be reduced, and the cost and size of the main relay, fuse, and even the entire system can be reduced.

[0012] Furthermore, any device can be used as the isolation circuit breaker, as long as it can maintain the energized state of the power line when ON and shut off the power line with an OFF signal from the control unit. For example, an electromechanical switch such as a latching relay or an electromagnetic switch can be used.

[0013] (2) In (1) above, it is preferable that the control unit is capable of transmitting ON / OFF signals to the pair of main relays of the current circuit, and that the control unit detects the activation of the abnormal interruption due to the interruption of the main relays by transmitting an OFF signal to the main relays.

[0014] Since the transmission of an OFF signal to the main relay from the control unit can detect the activation of an abnormal shutdown, which is the tripping of the main relay, it is possible to more quickly establish insulation between the power line and the battery using an insulating shutoff device.

[0015] (3) In (1) above, it is preferable that the fuse is made of a pyro fuse, the control unit is capable of transmitting a drive signal to the pyro fuse, and the activation of the abnormal interruption includes the transmission of a drive signal to the pyro fuse by the control unit. Since the activation of the abnormal interruption, which is the interruption of the fuse, can be detected by transmitting a drive signal to the pyro fuse while the battery and power line are interrupted by the driving of the pyro fuse, the establishment of insulation between the power line and the battery by the insulating interruption device can be realized more quickly.

[0016] The current circuit interruption method of the present disclosure is a current circuit interruption method performed using a current circuit interruption system comprising: (4) a pair of power lines connecting a battery and a load; a pair of main relays connected to the pair of power lines, respectively; a fuse and an isolation interruption device connected to either of the power lines; and a control unit that sends an ON / OFF signal to the isolation interruption device of the current circuit, wherein the isolation interruption device maintains the energized state of the power lines in the ON state, and the control unit includes the step of sending an OFF signal to the isolation interruption device to interrupt the isolation interruption device when it detects the activation of an abnormal interruption, including the interruption of the main relay or the fuse.

[0017] According to the current circuit interruption method of this disclosure, when the control unit detects the activation of an abnormal interruption, including the interruption of the main relay or fuse, it can perform the step of sending an OFF signal to the insulating interruption device and interrupting the insulating interruption device. Therefore, it is possible to perform the current circuit interruption method that can be realized by the circuit interruption system described in the embodiment of (1) above, and the same effects as the embodiment of (1) above can be achieved.

[0018] <Details of Embodiments of the Disclosure> Specific examples of the current circuit interruption system and current circuit interruption method of the Disclosure will be described below with reference to the drawings. However, the Disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope of the Claims as indicated by the Claims.

[0019] <Embodiment 1> Hereinafter, the current circuit interruption system 10 of Embodiment 1 of the present disclosure will be described with reference to Figures 1 and 2. This current circuit interruption system 10 is applicable, for example, to electric vehicles and hybrid vehicles, and in the event of a vehicle emergency such as an accident, the current flowing through the current circuit 14 can be stably interrupted by performing a predetermined circuit interruption operation 12 (see Figure 2). Note that for multiple identical components, reference numerals may be assigned to only some of the components, while the reference numerals for other components may be omitted.

[0020] <Current Circuit Interruption System 10> As shown in Figure 1, the current circuit 14 in the current circuit interruption system 10 includes a pair of power lines 22, 22 (+-side power line 22a and --side power line 22b) connecting the battery 16 and the load, which is the inverter 18 and motor 20, and a pair of main relays 24, 24 (+-side main relay 24a, which is the main relay on one side, and --side main relay 24b, which is the main relay on the other side) connected to each power line 22a and 22b, respectively. A fuse 26 and an isolation interruption device 28 are connected to one of the power lines 22a and 22b (in Embodiment 1, the --side power line 22b). The current circuit interruption system 10 also includes a control unit 30 that sends ON / OFF signals to the isolation interruption device 28 of the current circuit 14.

[0021] <Current Circuit 14> As described above, the current circuit 14 is equipped with power lines 22a and 22b to which the main relays 24a and 24b are connected. In Embodiment 1, the current sensor 32 is connected to the battery 16 side of the positive power line 22a, which is closer to the battery 16 than the positive main relay 24a. Also, as described above, a fuse 26 and an insulating circuit breaker 28 are connected to the negative power line 22b, which is closer to the battery 16 than the negative main relay 24b. A capacitor 34 is connected in parallel with the inverter 18 between the positive power line 22a and the negative power line 22b. The power lines 22a and 22b connect the battery 16 and the inverter 18, and the motor 20 is also connected to the inverter 18. In other words, the battery 16 and the motor 20 are connected via the inverter 18.

[0022] In the current circuit 14 described above, each main relay 24a, 24b and fuse 26 may be placed, for example, in an electrical junction box 36 shown by a dashed line in Figure 1. In the current circuit 14, known components can be used for the battery 16, inverter 18, motor 20, current sensor 32, and capacitor 34, which are provided outside the electrical junction box 36.

[0023] Furthermore, the specific structure of each main relay 24a, 24b provided in the electrical connection box 36 is not limited, and known structures can be used. However, in Embodiment 1, known mechanical relays (contact relays) are used as each main relay 24a, 24b. Note that each main relay 24a, 24b may be a semiconductor relay (non-contact relay). ON / OFF signals for each main relay 24a, 24b can be transmitted, for example, from the control unit 30 described above.

[0024] Furthermore, a known fuse 26 may also be used. The fuse 26 may be a known fused fuse or a pyro fuse, but in Embodiment 1, a pyro fuse is used as the fuse 26. When this fuse 26 is cut (blown if it is a fused fuse), the battery 16 is disconnected from the current circuit 14. If the fuse 26 is a pyro fuse, a drive signal for driving the pyro fuse may be transmitted, for example, from the control unit 30 described above.

[0025] <Isolation Disconnection Device 28> As described above, the isolation disconnection device 28 constitutes a part of the current circuit 14, and when the isolation disconnection device 28 and each main relay 24a, 24b are both in the ON state, the energized state of the current circuit 14 (each power line 22a, 22b) is maintained. Furthermore, if an accident occurs and, for example, an abnormality is detected in the control unit 30, an OFF signal is sent to each main relay 24a, 24b and fuse 26 to turn them OFF, and then the control unit 30 sends an OFF signal to the isolation disconnection device 28 to disconnect the current circuit 14 (each power line 22a, 22b). In other words, when the control unit 30 detects the activation of abnormal disconnection (disconnection of each main relay 24a, 24b and fuse 26 in the event of an abnormality), it sends an OFF signal to the isolation disconnection device 28 to disconnect the isolation disconnection device 28.

[0026] The specific electronic components constituting the isolation interruption device 28 are not limited and can be any component capable of interrupting the current circuit 14 (each power supply line 22a, 22b). For example, relays and fuses can be used, but components that can return to the state before interruption, such as relays, are preferred. In particular, it is desirable for the isolation interruption device 28 to be a latching relay, for example, which maintains its state once a signal is input.

[0027] <Control Unit 30> As described above, the control unit 30 of Embodiment 1, when it detects the activation of an abnormal interruption, sends an OFF signal to the isolation interruption device 28, thereby shutting off the isolation interruption device 28 and disconnecting the current circuit 14 (each power supply line 22a, 22b). The activation of the abnormal interruption includes, for example, the shutdown of each main relay 24a, 24b or the shutdown of the fuse 26.

[0028] In other words, when an abnormality occurs in the vehicle due to an accident or the like, it is necessary to urgently shut off the current circuit 14. The control unit 30 sends an OFF signal to at least one of the main relays 24a and 24b, causing the main relays 24a and 24b to shut off, thereby shutting off the current circuit 14. Upon receiving this OFF signal to the main relays 24a and 24b, the control unit 30 detects that circuit shutdown is occurring in an abnormal state (activation of abnormal shutdown) and sends an OFF signal to the isolation shutdown device 28, which shuts off the isolation shutdown device 28. This ensures that the current circuit 14 is shut off more reliably.

[0029] Similarly, in the event of an abnormality, depending on the current value detected by the current sensor 32, instead of turning off the main relays 24a and 24b, the fuse 26 may be used to interrupt the current. In that case, the control unit 30 sends a drive signal to the fuse 26 (pyro fuse), which triggers the fuse 26 to interrupt the current circuit 14. Upon receiving this drive signal to the fuse 26, the control unit 30 detects that circuit interruption is occurring in an abnormal state (activation of abnormal interruption) and sends an OFF signal to the isolation interruption device 28, thereby interrupting the isolation interruption device 28. This ensures that the current circuit 14 is interrupted more reliably.

[0030] The specific configuration of the control unit 30 is not limited, but for example, it may include a microcomputer mounted on a circuit board electrically connected to the current circuit 14, and this microcomputer can send ON / OFF signals to each of the main relays 24a and 24b, and send drive signals to the fuse 26 (pyro fuse).

[0031] <Current Circuit Interruption Method> The current circuit interruption method according to this disclosure will be described below, with particular use of Figure 2. That is, the current circuit interruption method of this disclosure performs the circuit interruption operation 12 described below using the current circuit interruption system 10 described above. Figure 2 shows the conduction state of the current circuit 14, the conduction state of the isolation interruption device 28, and the ON / OFF states of the + side main relay 24a and the - side main relay 24b, with the horizontal axis being the time axis. Note that Figure 2 is a simplified representation of the conduction state of the current circuit 14, the conduction state of the isolation interruption device 28, and the ON / OFF states of the + side main relay 24a and the - side main relay 24b over time, and the length of time shown on the time axis (the length of time shown in the left-right direction in Figure 2) may not match the actual length of time.

[0032] As shown in Figure 2, the isolation circuit breaker 28 is basically always ON. Before the vehicle starts up, both the +-side main relay 24a and the --side main relay 24b are OFF, and as a result, the current circuit 14 is de-energized. When the vehicle starts up, for example, the control unit 30 sends an ON signal to the --side main relay 24b, causing the --side main relay 24b to turn ON. Subsequently, the control unit 30 sends an ON signal to the +-side main relay 24a, causing the +-side main relay 24a to turn ON. As a result, both main relays 24a and 24b are ON, and the current circuit 14 becomes energized. As a result, the vehicle enters a normal state where it can be driven.

[0033] Subsequently, at some point, an abnormality occurs in the vehicle due to an accident or other reason. In such a case, if a circuit is short-circuited, for example, and a relatively large current is detected by the current sensor 32, the control unit 30 sends an OFF signal to the + side main relay 24a and the - side main relay 24b to turn off each main relay 24a and 24b. This is expected to de-energize the current circuit 14. However, if the main relays 24a and 24b are turned off while a relatively large current is flowing, the main relays 24a and 24b may be damaged, resulting in incomplete current interruption and maintaining a weak conduction state. In short, as shown by the dashed line in Figure 2, even if the main relays 24a and 24b are turned off, the current circuit 14 may remain energized. To resolve such problems, the control unit 30 sends an OFF signal to the isolation circuit breaker 28 to turn it off. As a result, weak currents that could not be completely interrupted by turning off each of the main relays 24a and 24b can be reliably interrupted by the insulating interruption device 28, thereby more reliably keeping the current circuit 14 de-energized.

[0034] Furthermore, regardless of whether the current is completely cut off by the main relays 24a and 24b as a result of the OFF operation of each main relay 24a and 24b, resulting in the current circuit 14 being de-energized, or whether the current is not completely cut off and the current circuit 14 remains energized, the OFF operation of the isolation circuit breaker 28 is performed. In other words, even when the current is completely cut off by the main relays 24a and 24b and the current circuit 14 is de-energized, the isolation circuit breaker 28 can be set to the OFF state. Therefore, for example, when an abnormality is detected by the current value detected by the current sensor 32 in the event of an accident, the control unit 30 will send an OFF signal to each main relay 24a and 24b depending on the magnitude of the current value. By detecting the transmission of this OFF signal to each main relay 24a and 24b (in short, the activation of abnormal circuit breaker), the control unit 30 sends an OFF signal to the isolation circuit breaker 28 to shut down the isolation circuit breaker 28.

[0035] Alternatively, in the event of an accident or other malfunction in the vehicle, a current of such large value may flow that simply tripping the main relays 24a and 24b is insufficient to de-energize the current circuit 14. In such cases, instead of simply turning off the main relays 24a and 24b, the control unit 30 sends a drive signal to the fuse 26 (pyro fuse) to cut the fuse 26. This is expected to de-energize the current circuit 14, but for more reliable circuit disconnection, an OFF signal is further sent to the isolation circuit breaker 28 to turn it OFF. As a result, the current circuit 14 can be de-energized more reliably. Therefore, when an abnormality is detected by the current value detected by the current sensor 32, for example in the event of an accident, the control unit 30 will send a drive signal to the fuse 26 (pyro fuse) depending on the magnitude of the current value. By detecting the transmission of this drive signal to the fuse 26 (in short, the activation of abnormal shutdown), the control unit 30 sends an OFF signal to the isolation shutdown device 28 to shut off the isolation shutdown device 28.

[0036] Based on the above, the current circuit interruption method of the present disclosure includes the step of transmitting an OFF signal to the isolation interruption device 28 and interrupting the isolation interruption device 28 when the control unit 30 detects the activation of an abnormal interruption, including the interruption of each main relay 24a, 24b or fuse 26.

[0037] With the current circuit interruption system 10 and the current circuit interruption method performed using the current circuit interruption system 10 as described above, when an abnormality such as an accident occurs, there is a risk that a relatively large current may flow, and simply turning off each main relay 24a, 24b or cutting the fuse 26 may not completely interrupt the current circuit 14. Therefore, in this disclosure, an insulating interruption device 28 is provided in the current circuit interruption system 10, and the insulating interruption device 28 can interrupt currents that could not be completely interrupted by the interruption by each main relay 24a, 24b or by cutting the fuse 26. In particular, since such an insulating interruption device 28 can be provided on the conventional circuit without changing the configuration of the conventional current circuit, the current circuit interruption system 10 can be configured using the existing current circuit. Furthermore, in the current circuit interruption system 10, it is also possible to assign the insulating performance to the insulating interruption device 28, and the insulating performance required for each main relay 24a, 24b and the fuse 26 can be relatively reduced. As a result, each main relay 24a, 24b and fuse 26 can have a relatively simple structure, and miniaturization of the existing current circuit portion of the current circuit interruption system 10 is achieved.

[0038] The above-mentioned interruption by the insulating interruption device 28 is performed by the control unit 30 transmitting an OFF signal to the insulating interruption device 28. The transmission of this OFF signal to the insulating interruption device 28 may be performed when the control unit 30 detects the interruption of each main relay 24a, 24b (activation of abnormal interruption) by transmitting an OFF signal to each main relay 24a, 24b when there is a vehicle abnormality. This makes it possible to interrupt the insulating interruption device 28 in conjunction with the interruption operation of each main relay 24a, 24b.

[0039] If the fuse 26 is a pyro fuse, the transmission of an OFF signal to the insulating circuit breaker 28 may be performed by the control unit 30 detecting the tripping of the fuse 26 (activation of abnormal tripping) by transmitting a drive signal to the fuse 26 (pyro fuse) when there is a vehicle abnormality, similar to the above. This allows the insulating circuit breaker 28 to be tripped immediately after the fuse 26 is tripped.

[0040] <Modifications> Although Embodiment 1 has been described in detail above as a specific example of the present disclosure, the present disclosure is not limited by this specific description. Modifications, improvements, etc., to the extent that they can achieve the purpose of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiments are also included in the technical scope of the present disclosure.

[0041] (1) The current circuit relating to this disclosure is not limited to that described in the above embodiment. For example, a precharge circuit may be provided in at least one of the pair of power lines (+-side power line 22a and --side power line 22b) that includes, for example, a precharge resistor and a precharge relay connected in series to bypass the main relay. Furthermore, the connection location of the fuse and the insulating circuit breaker is not limited to the configuration described in the above embodiment. For example, it may be on the +-side power line 22a side, or on the --side power line 22b, it may be on the inverter 18 side of the --side main relay 24b.

[0042] (2) In the above embodiment, the fuse 26 was a pyro fuse, but it may also be a fusible fuse.

[0043] (3) In the above embodiment, when the main relays 24a and 24b were shut off, they were shut off simultaneously. However, the embodiment is not limited to this, and they may be shut off sequentially.

[0044] 10 Current circuit interruption system 12 Circuit interruption operation 14 Current circuit 16 Battery 18 Inverter (load) 20 Motor (load) 22 Power line 22a + side power line 22b - side power line 24 Main relay 24a + side main relay 24b - side main relay 26 Fuse 28 Isolation interruption device 30 Control unit 32 Current sensor 34 Capacitor 36 Electrical junction box

Claims

1. A current circuit interruption system comprising: a current circuit including a pair of power lines connecting a battery and a load; a pair of main relays connected to each of the pair of power lines; a fuse and an isolation interruption device connected to either of the power lines; and a control unit that sends an ON / OFF signal to the isolation interruption device of the current circuit, wherein the isolation interruption device maintains the energized state of the power lines when in the ON state, and the control unit transmits an OFF signal to the isolation interruption device to interrupt the isolation interruption device when it detects the activation of an abnormal interruption, including the interruption of the main relay or the fuse.

2. The current circuit interruption system according to claim 1, wherein the control unit is capable of transmitting ON / OFF signals to a pair of main relays of the current circuit, and the control unit detects the activation of the abnormal interruption due to the interruption of the main relays by transmitting an OFF signal to the main relays.

3. The current circuit interruption system according to claim 1, wherein the fuse is composed of a pyro fuse, the control unit is capable of transmitting a drive signal to the pyro fuse, and the activation of the abnormal interruption includes the transmission of a drive signal to the pyro fuse by the control unit.

4. A current circuit interruption method performed using a current circuit interruption system comprising: a current circuit including a pair of power lines connecting a battery and a load; a pair of main relays connected to each of the pair of power lines; a fuse and an isolation interruption device connected to either of the power lines; and a control unit that sends an ON / OFF signal to the isolation interruption device of the current circuit, wherein the isolation interruption device maintains the energized state of the power lines in the ON state, the method comprising the step of sending an OFF signal to the isolation interruption device to interrupt the isolation interruption device when the control unit detects the activation of an abnormal interruption, including the interruption of the main relay or the fuse.

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