In-vehicle cutting device

Abstract

A vehicle (10) is provided with a battery (11), a charging socket (12), a voltage conversion unit (13), a conductive line (for example, a first conductive line (14)), and a reference conductive line (19). The charging socket (12) connects the reference conductive line (19) to a protective ground line (87) of the charging device (80). A vehicle-mounted shutoff device (30) is provided with a shutoff unit (31), a current detection unit (32), an overcurrent detection circuit (33), and a drive circuit (34). The cut-off unit (31) is provided in the conductive line, and switches to a cut-off state in response to the input of the drive signal to the input unit (31A). The current detection unit (32) detects a current flowing through the conductive line or the reference conductive line (19). An overcurrent detection circuit (33) detects an overcurrent state on the basis of the detection result of the current detection unit (32). The drive circuit (34) supplies a drive signal to an input unit (31A) of the cutoff unit (31) when an overcurrent state is detected by the overcurrent detection circuit (33).

Description

TECHNICAL FIELD

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

[0002] A technology is known in which a battery mounted on a vehicle is charged by connecting a plug of a charging device to a charging inlet of the vehicle. At the time of charging, a vehicle body is connected to a protective earth line of the charging device via the charging inlet. Thereby, the vehicle body is grounded. However, in a case where a larger current than expected flows in the protective earth line due to an earth fault or the like, the protective earth line is fused, and the grounding state of the vehicle body can be released.

[0003] Therefore, in a case where an overcurrent flows in the protective earth line, a power line is considered to be cut off. A leakage detection device that detects a leakage is disclosed in Patent Literature 1. The leakage detection device includes a battery voltage sensor, a first series circuit, a second series circuit, a voltage distributor, an analog-digital converter, and a control portion. The battery voltage sensor is configured to measure a battery voltage between a positive terminal and a negative terminal of a battery. The first series circuit includes a first resistor and a first switch connected in series between a first node connected to the negative terminal and a second node connectable to a chassis. The second series circuit includes a second resistor and a second switch connected in series between the second node and a third node connected to the positive terminal. The voltage distributor includes a third resistor and a fourth resistor connected in parallel to the first series circuit and connected in series through a fourth node. The analog-digital converter is configured to generate a digital signal representing a voltage between the first node and the fourth node. The control portion is connected to the battery voltage sensor, the first switch, the second switch, and the analog-digital converter in an operable manner. The control portion determines a first detection voltage based on a digital signal at a first detection timing at which a first leakage detection mode in which the first switch is controlled to be in an on state and the second switch is controlled to be in an off state is executed. The control portion determines a second detection voltage based on a digital signal at a second detection timing at which a second leakage detection mode in which the first switch is controlled to be in an off state and the second switch is controlled to be in an on state is executed. The control portion determines a first insulation resistance between the positive terminal and the chassis and a second insulation resistance between the negative terminal and the chassis based on the battery voltage, the first detection voltage, and the second detection voltage. The control portion judges a leakage of the battery based on the first insulation resistance and the second insulation resistance.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2022-524031 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, the structure of Patent Literature 1 envisages detection of the leakage in the period during which the charge and discharge of the battery is interrupted, and is not suitable for detection in the charge of the battery. For example, in the structure of Patent Literature 1, the detected voltage is converted into a digital signal and leakage is detected by digital processing. Therefore, in the structure of Patent Literature 1, it is difficult to promptly perform detection of the leakage, and it is also difficult to promptly cut off the power line at the time of leakage.

[0009] An object of the present disclosure is to provide a technology capable of promptly cutting off current flowing through a conductive line at the time of a ground fault in the charge of a vehicle-mounted battery by a charging device outside a vehicle.

[0010] Means for solving the problem

[0011] The vehicle-mounted cut-off device of the present disclosure includes a battery, a charging inlet connected to a charging device outside a vehicle, a voltage conversion section that converts voltage input from the charging inlet side and outputs to the battery side, a conductive line provided between the charging inlet and the voltage conversion section, and a reference conductive line electrically connected to a vehicle body. The charging inlet has a connection section that connects the reference conductive line and a protective ground line of the charging device. The vehicle-mounted cut-off device has a cut-off section provided to the conductive line, which switches from a permitted state in which current is permitted to flow through the conductive line to a cut-off state according to input of a drive signal to an input section, a current detection section that detects current flowing through the conductive line or the reference conductive line, an overcurrent detection circuit that detects an overcurrent state based on a detection result of the current detection section, and a drive circuit that provides the drive signal to the input section of the cut-off section when the overcurrent state is detected by the overcurrent detection circuit.

[0012] Effects of the invention

[0013] The technology of the present disclosure can promptly cut off current flowing through a conductive line at the time of a ground fault in the charge of a vehicle-mounted battery by a charging device outside a vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0014] [ Figure 1 ] Figure 1 is a configuration view that schematically shows a vehicle and a charging device including a vehicle-mounted cut-off device of a first embodiment.

[0015] [ Figure 2 ] Figure 2 is a configuration view that schematically shows a vehicle and a charging device including a vehicle-mounted cut-off device of a second embodiment.

[0016] [ Figure 3 ] Figure 3 is a configuration view that schematically shows a vehicle and a charging device including a vehicle-mounted cut-off device of a third embodiment.

[0017] [ Figure 4 ] Figure 4 is a configuration diagram schematically showing a vehicle and a charging device including the vehicle-mounted cutoff device of the fourth embodiment.

[0018] [ Figure 5 ] Figure 5 is a configuration diagram schematically showing a vehicle and a charging device including the vehicle-mounted cutoff device of the fifth embodiment. DETAILED DESCRIPTION

[0019] [Explanation of Embodiments of the Present Disclosure]

[0020] Hereinafter, embodiments of the present disclosure will be exemplified.

[0021] [1] A vehicle-mounted cutoff device for a vehicle, the vehicle having: a battery; a charging inlet connected to a charging device outside the vehicle; a voltage conversion section that converts a voltage input from the charging inlet side and outputs to the battery side; a conductive line provided between the charging inlet and the voltage conversion section; and a reference conductive line electrically connected to a vehicle body, the charging inlet having a connection section that connects the reference conductive line and a protective ground line of the charging device, the vehicle-mounted cutoff device having: a cutoff section provided to the conductive line, which switches from an allowed state in which current is allowed to flow through the conductive line to a cutoff state according to a case where a drive signal is input to an input section; a current detection section that detects current flowing in the conductive line or the reference conductive line; an overcurrent detection circuit that detects an overcurrent state based on a detection result of the current detection section; and a drive circuit that provides the drive signal to the input section of the cutoff section in a case where the overcurrent state is detected by the overcurrent detection circuit.

[0022] The above vehicle-mounted cutoff device can switch the cutoff section to the cutoff state by the drive circuit in a case where the overcurrent state is detected by the overcurrent detection circuit. Therefore, the above vehicle-mounted cutoff device can quickly cut off current flowing in the conductive line when a ground fault occurs in charging of the battery by the charging device outside the vehicle.

[0023] [2] The vehicle-mounted cutoff device described in [1], wherein the current detection section detects current flowing in the reference conductive line.

[0024] The above vehicle-mounted cutoff device can more reliably detect current flowing in the protective ground line by detecting current flowing in the reference conductive line. Therefore, the above vehicle-mounted cutoff device can more accurately detect a case where overcurrent flows in the protective ground line, and can quickly cut off current flowing in the conductive line according to the detection.

[0025] 〔3〕 The vehicle-mounted cutoff device according to any one of 〔1〕 to 〔2〕, wherein the conductive line and the reference conductive line are insulated from each other via the current detection section, the overcurrent detection circuit, the drive circuit, and the cutoff section.

[0026] The vehicle-mounted cutoff device described above can prevent the conductive line and the reference conductive line from being short-circuited in a normal state in which no ground fault occurs.

[0027] 〔4〕 The vehicle-mounted cutoff device according to 〔3〕, wherein the vehicle-mounted cutoff device has a signal insulation section that is provided at least one of between the current detection section and the overcurrent detection circuit, between the overcurrent detection circuit and the drive circuit, and between the drive circuit and the cutoff section, for insulating and transmitting a signal.

[0028] The vehicle-mounted cutoff device described above can insulate the conductive line and the reference conductive line from each other even without providing an insulating structure inside the current detection section, the overcurrent detection circuit, the drive circuit, and the cutoff section.

[0029] 〔5〕 The vehicle-mounted cutoff device according to any one of 〔2〕 to 〔4〕, wherein the reference conductive line has a first parallel conductive line and a second parallel conductive line that are provided in parallel with each other between the vehicle body and the connection section.

[0030] In a structure in which the current detection section detects a current flowing in the reference conductive line, in a case where the current detection section is disposed close to the current detection section, the overcurrent detection circuit, the drive circuit, and the cutoff section, the reference conductive line is likely to be long, and the resistance value of the reference conductive line is likely to be large. If the resistance value of the reference conductive line is large, when a ground fault occurs, it is difficult for the current to be released to the protective ground line. According to the vehicle-mounted cutoff device described above, the reference conductive line is composed of the first parallel conductive line and the second parallel conductive line that are provided in parallel with each other, and thus it is easy to reduce the resistance value of the reference conductive line.

[0031] 〔6〕 The vehicle-mounted cutoff device according to 〔5〕, wherein the first parallel conductive line is short-circuited to the vehicle body and the connection section, a resistance section is provided in the second parallel conductive line, and the current detection section detects a current flowing in the second parallel conductive line.

[0032] The current detection section of the vehicle-mounted cutoff device described above detects a current that is suppressed by the resistance section, and thus it is easy to downsize the current detection section.

[0033] 〔7〕 The in-vehicle cutoff device of 6, wherein the current detection section has the resistance section and a differential amplifier circuit that amplifies and outputs a voltage across the resistance section.

[0034] The current detection section of the in-vehicle cutoff device described above can detect a current using the resistance section provided to the second parallel conductive line.

[0035] [Details of Embodiments of the Present Disclosure]

[0036] <First Embodiment>

[0037] Figure 1 A vehicle 10 including an in-vehicle cutoff device 30 and a charging device 80 are shown. The vehicle 10 is a vehicle that travels with a battery 11 as a power source, for example, an electric vehicle. The battery 11 is charged by the charging device 80 outside the vehicle 10.

[0038] The vehicle 10 is provided with the battery 11, a charging inlet 12, a voltage conversion section 13, a first conductive line 14, a second conductive line 15, relays 16, 17, a vehicle body 18, a reference conductive line 19, a control section 20, and the in-vehicle cutoff device 30.

[0039] The battery 11 is, for example, a high-voltage battery that can supply electric power to a motor for driving. The motor is a motor that provides power to wheels of the vehicle 10. The output voltage of the battery 11 at full charge is, for example, 800 V. The battery 11 can be constituted by a secondary battery such as a lithium-ion battery, or by another kind of storage battery.

[0040] The charging inlet 12 is connected to the charging device 80 outside the vehicle 10. The charging inlet 12 is supplied with electric power from the charging device 80. The charging inlet 12 has a first terminal 12A, a second terminal 12B, and a connection section 12C. The connection section 12C is constituted to include a connection terminal.

[0041] The charging device 80 is, for example, a device that supplies a direct-current voltage of 400 V. The charging device 80 is provided with a first counterpart terminal 81 connected to the first terminal 12A, a second counterpart terminal 82 connected to the second terminal 12B, and a counterpart connection section 83 connected to the connection section 12C. The counterpart connection section 83 is constituted to include a counterpart connection terminal. The charging device 80 is provided with a charger 84. The charger 84 converts alternating-current electric power of a commercial power source or the like into direct-current electric power and outputs it. The charger 84 is, for example, constituted as an off-vehicle charger.

[0042] The charging device 80 includes a positive electrode side supply line 85, a negative electrode side supply line 86, and a protection ground line 87. The positive electrode side supply line 85 and the negative electrode side supply line 86 are electric lines that supply electric power from the charger 84 to the charging jack 12 side. One end of the positive electrode side supply line 85 is electrically connected to a terminal on the positive electrode side of the charger 84. The other end of the positive electrode side supply line 85 is electrically connected to the first counterpart terminal 81. One end of the negative electrode side supply line 86 is electrically connected to a terminal on the negative electrode side of the charger 84. The other end of the negative electrode side supply line 86 is electrically connected to the second counterpart terminal 82. One end of the protection ground line 87 is grounded. The other end of the protection ground line 87 is electrically connected to the counterpart connection portion 83.

[0043] The charging device 80 includes a first SPD 88 and a second SPD 89. The first SPD 88 and the second SPD 89 are surge protective devices. The first SPD 88 is provided between the positive electrode side supply line 85 and the protection ground line 87. The first SPD 88 has a function of releasing an overvoltage generated in the positive electrode side supply line 85 to the protection ground line 87. The second SPD 89 is provided between the negative electrode side supply line 86 and the protection ground line 87. The second SPD 89 has a function of releasing an overvoltage generated in the negative electrode side supply line 86 to the protection ground line 87.

[0044] The charging device 80 includes a plug that is not shown. The plug is connected to the charging jack 12. The charging device 80 supplies direct-current electric power to the charging jack 12 via the plug.

[0045] A voltage conversion portion 13 is provided between the charging jack 12 and the battery 11. The voltage conversion portion 13 performs a conversion operation of converting a voltage input from the charging jack 12 side and outputting to the battery 11 side. In the present embodiment, the voltage conversion portion 13 performs a step-up operation of stepping up a voltage input from the charging jack 12 side and outputting to the battery 11 side. The voltage conversion portion 13 is constituted by, for example, a DCDC converter.

[0046] The first conductive line 14 corresponds to an example of a conductive line. The first conductive line 14 is provided between the charging jack 12 and the voltage conversion portion 13. The first conductive line 14 has a first positive electrode side conductive line 14A and a first negative electrode side conductive line 14B. One end of the first positive electrode side conductive line 14A is electrically connected to the first terminal 12A. The other end of the first positive electrode side conductive line 14A is electrically connected to the voltage conversion portion 13. One end of the first negative electrode side conductive line 14B is electrically connected to the second terminal 12B. The other end of the first negative electrode side conductive line 14B is electrically connected to the voltage conversion portion 13.

[0047] The second conductive line 15 is provided between the voltage conversion section 13 and the battery 11. The second conductive line 15 has a second positive electrode side conductive line 15A and a second negative electrode side conductive line 15B. One end of the second positive electrode side conductive line 15A is electrically connected to the terminal on the high potential side of the battery 11. The other end of the second positive electrode side conductive line 15A is electrically connected to the voltage conversion section 13. One end of the second negative electrode side conductive line 15B is electrically connected to the terminal on the low potential side of the battery 11. The other end of the second negative electrode side conductive line 15B is electrically connected to the voltage conversion section 13.

[0048] The voltage conversion section 13 described above converts the voltage applied to the first conductive line 14 and applies it to the second conductive line 15 in the conversion operation. More specifically, the voltage conversion section 13 converts the voltage applied between the first positive electrode side conductive line 14A and the first negative electrode side conductive line 14B and applies it between the second positive electrode side conductive line 15A and the second negative electrode side conductive line 15B.

[0049] The relay 16 is provided to the first positive electrode side conductive line 14A. The relay 17 is provided to the first negative electrode side conductive line 14B. The relays 16, 17 allow the current to flow between the charging jack 12 and the voltage conversion section in the on state. The relays 16, 17 cut off the current flowing between the charging jack 12 and the voltage conversion section 13 in the off state. In Figure 1 In the example shown, the relays 16, 17 are mechanical relays having contacts, but can be semiconductor relays configured of semiconductor switching elements.

[0050] The reference conductive line 19 is electrically connected to the vehicle body 18. The reference conductive line 19 is electrically connected to the connection portion 12C of the charging jack 12. In a state where the counterpart connection portion 83 of the charging device 80 is connected to the connection portion 12C, the reference conductive line 19 is electrically connected to the protective ground line 87. Thus, the vehicle body 18 is electrically connected to the protective ground line 87.

[0051] The control section 20 controls the voltage conversion section 13, the relays 16, 17. The control section 20 is configured of, for example, a microcomputer. The control section 20 is configured of, for example, an MCU (Micro Controller Unit). The control section 20 includes an information processing section such as a CPU, a storage section such as a ROM, a RAM, and the like.

[0052] The control section 20 controls the relays 16, 17 to be in an off state and stops the voltage conversion section 13 in a state where the plug of the charging device 80 is not connected to the charging inlet 12. The control section 20 switches the relays 16, 17 to be in an on state and causes the voltage conversion section 13 to perform a conversion operation in a case where the plug of the charging device 80 is connected to the charging inlet 12. The control section 20, for example, steps up the voltage of 400 V applied to the first conductive line 14 to 800 V and applies it to the second conductive line 15. Thereby, the battery 11 is supplied with electric power of 800 V. Further, the control section 20 determines whether or not the plug of the charging device 80 is connected to the charging inlet 12, for example, on the basis of a signal from the charging device 80.

[0053] In the above-described structure, the vehicle body 18 is electrically connected to the protective ground line 87 at the time of charging the battery 11 from the charging device 80. Therefore, even if a ground fault occurs, it is possible to avoid electric shock of a person touching the vehicle body 18. However, in a case where, for example, the second conductive line 15 to which the voltage stepped up by the voltage conversion section 13 is applied has a ground fault, the positive electrode side supply line 85 and the negative electrode side supply line 86 of the charging device 80 are supplied with the stepped-up voltage via the first conductive line 14. In this case, it is possible that the first SPD 88 and the second SPD 89 are applied with an unexpected overvoltage and have a failure. For example, when the second SPD 89 has a failure, the negative electrode side supply line 86 can be short-circuited to the protective ground line 87 via the second SPD 89. When the negative electrode side supply line 86 is short-circuited to the protective ground line 87, an unexpected large current flows in the protective ground line 87, and the protective ground line 87 can be fused. The purpose of the in-vehicle cut-off device 30 is to rapidly cut off the electric power line before the protective ground line 87 is fused in such a situation.

[0054] The in-vehicle cut-off device 30 is a device for the vehicle 10. The in-vehicle cut-off device 30 cuts off a current flowing through the first conductive line 14 in a case where an overcurrent exceeding a threshold value flows through the first conductive line 14. The in-vehicle cut-off device 30 has a cut-off section 31, a current detection section 32, an overcurrent detection circuit 33, and a drive circuit 34.

[0055] The cutout 31 is provided to the first conductive line 14 (more specifically, the first negative electrode side conductive line 14B). The cutout 31 has an input 31A. The cutout 31 switches from a permitted state to a cutout state in accordance with input of a drive signal to the input 31A. The permitted state is a state in which the current is allowed to flow through the first conductive line 14. The cutout state is a state in which the current is cut off from flowing through the first conductive line 14. The cutout 31 can be a structure that cannot be restored to the permitted state after becoming the cutout state, or can be a structure that can be restored. The structure that cannot be restored can be, for example, a pyrotechnic circuit breaker (for example, a PYROFUSE (registered trademark)) that physically cuts off the first conductive line 14 in accordance with input of the drive signal to the input 31A. The structure that can be restored is, for example, a switch. The switch can be a mechanical switch having a contact, or a semiconductor switch such as a MOSFET, an IGBT, or the like.

[0056] The current detection 32 detects the current flowing through the first conductive line 14. The current detection 32 can be a non-contact type configured in a non-contact manner with the first conductive line 14, or can be a contact type configured in a contact manner with the first conductive line 14. The non-contact type is constituted by, for example, a magnetic sensor such as a Hall element. The contact type is constituted by, for example, a shunt resistor and a differential amplifier that amplifies and outputs a voltage across the shunt resistor.

[0057] The overcurrent detection circuit 33 detects an overcurrent state based on a detection result of the current detection 32. The overcurrent detection circuit 33 is constituted by, for example, a known overcurrent detection circuit. The overcurrent detection circuit 33 determines whether or not a value of the current flowing through the first conductive line 14 exceeds a threshold value based on a detection signal of the current detection 32. The threshold value is a value larger than 0 A, and is a value larger than a maximum value of the current supplied by the charging device 80 at normal times. The overcurrent detection circuit 33 detects the overcurrent state in a case where it is determined that the value of the current flowing through the first conductive line 14 exceeds the threshold value. The overcurrent detection circuit 33 outputs an overcurrent signal in a case where it detects the overcurrent state.

[0058] The drive circuit 34 is constituted by, for example, a known drive circuit. The drive circuit 34 supplies the drive signal to the input 31A of the cutout 31 in a case where the overcurrent state is detected by the overcurrent detection circuit 33. Specifically, the drive circuit 34 supplies the drive signal to the input 31A of the cutout 31 in a case where the overcurrent signal is input.

[0059] The in-vehicle cutoff device 30 is set to an operable state regardless of whether or not the charging device 80 is connected to the charging inlet 12, for example. The current detection section 32 continuously detects the current flowing in the first conductive line 14 and outputs a signal indicating the detected value. The overcurrent detection circuit 33 continuously determines whether or not the current flowing in the first conductive line 14 exceeds a threshold value. The overcurrent detection circuit 33 outputs an overcurrent signal in a case where it is determined that the value of the current flowing in the first conductive line 14 exceeds the threshold value. The drive circuit 34 supplies a drive signal to the input section 31A of the cutoff section 31 in a case where the overcurrent signal is input. The cutoff section 31 is switched to the cutoff state in accordance with the drive signal supplied to the input section 31A. Thus, the current flowing in the first conductive line 14 is cut off.

[0060] The following description relates to the effect of the in-vehicle cutoff device 30 of the first embodiment. The in-vehicle cutoff device 30 is capable of switching the cutoff section 31 to the cutoff state by the drive circuit 34 in a case where an overcurrent state is detected by the overcurrent detection circuit 33 and the overcurrent state is detected. Thus, the in-vehicle cutoff device 30 is capable of rapidly cutting off the current flowing in the first conductive line 14 in a case where a ground fault occurs in charging of the battery 11 by the charging device 80 outside the vehicle 10.

[0061] <Second Embodiment>

[0062] In the first embodiment, the structure in which the current detection section detects the current flowing in the first conductive line is described. In the second embodiment, the structure in which the current detection section detects the current flowing in the reference conductive line is described. In addition, the same reference numerals are attached to the same structures as those of the first embodiment and detailed description is omitted in the description of the second embodiment.

[0063] A vehicle 210 including the in-vehicle cutoff device 230 of the second embodiment and the charging device 80 are disclosed in Figure 2 A vehicle 210 including the in-vehicle cutoff device 230 of the second embodiment and the charging device 80 are disclosed in

[0064] The in-vehicle cutoff device 230 is a device for the vehicle 210. The in-vehicle cutoff device 230 has the cutoff section 31, the current detection section 232, the overcurrent detection circuit 33, the drive circuit 34, and the signal insulation section 35.

[0065] The current detection section 232 detects the current flowing in the reference conductive line 19. The current detection section 232 can be a non-contact type configured in a non-contact manner with the reference conductive line 19, or a contact type configured in a contact manner with the reference conductive line 19. The non-contact type is constituted by, for example, a magnetic sensor such as a Hall element. The contact type is constituted by, for example, a shunt resistor and a differential amplifier that amplifies and outputs the voltage across the shunt resistor.

[0066] The signal insulation section 35 is provided between the overcurrent detection circuit 33 and the drive circuit 34. The signal insulation section 35 insulates between the overcurrent detection circuit 33 and the drive circuit 34, and outputs a signal input from the overcurrent detection circuit 33 side to the drive circuit 34 side. The signal insulation section 35 is constituted by, for example, an isolator, an opto-coupler, a pulse transformer, or the like.

[0067] Between the first conductive line 14 and the reference conductive line 19 via the current detection section 232, the overcurrent detection circuit 33, the drive circuit 34, and the cutoff section 31 is insulated by the signal insulation section 35.

[0068] The in-vehicle cutoff device 230 is set to an operable state regardless of whether or not the charging device 80 is connected to the charging inlet 12, for example. The current detection section 232 continuously detects the current flowing in the reference conductive line 19, and outputs a signal indicating the detected value. The overcurrent detection circuit 33 continuously performs a determination as to whether or not the current flowing in the reference conductive line 19 exceeds a threshold value. The overcurrent detection circuit 33 outputs an overcurrent signal in a case where it is determined that the value of the current flowing in the reference conductive line 19 exceeds the threshold value. The signal insulation section 35 outputs the overcurrent signal input from the overcurrent detection circuit 33 side to the drive circuit 34 side. The drive circuit 34, in a case where the overcurrent signal is input, supplies a drive signal to the input section 31A of the cutoff section 31. The cutoff section 31 switches to a cutoff state in accordance with the drive signal being supplied to the input section 31A. Thus, the current flowing in the first conductive line 14 is cut off.

[0069] The following description relates to the effect of the in-vehicle cutoff device 230 of the second embodiment. The in-vehicle cutoff device 230, by detecting the current flowing in the reference conductive line 19, can more reliably detect the current flowing in the protective earth line 87. Therefore, the in-vehicle cutoff device 230 can more accurately detect a case where an overcurrent flows in the protective earth line 87, and can rapidly cut off the current flowing in the first conductive line 14 in accordance with the detection.

[0070] The in-vehicle cutoff device 230 can prevent the first conductive line 14 and the reference conductive line 19 from being short-circuited in a normal state where no ground fault occurs.

[0071] The in-vehicle cutoff device 230 can insulate the first conductive line 14 from the reference conductive line 19 even without an insulating structure provided inside the current detection unit 232, the overcurrent detection circuit 33, the drive circuit 34, and the cutoff unit 31.

[0072] <Third Embodiment>

[0073] In the third embodiment, the structure of the current detection unit that detects a current flowing in the reference conductive line is described as in the second embodiment. In the third embodiment, the structure in which the reference conductive line having the first and second parallel conductive lines provided in parallel with each other as a detection target is described. In the description of the third embodiment, the same reference numerals are assigned to the same structures as in the second embodiment, and detailed description is omitted.

[0074] In Figure 3 The vehicle 310 and the charging device 80 including the in-vehicle cutoff device 330 of the third embodiment are disclosed. The vehicle 310 is provided with the battery 11, the charging inlet 12, the voltage conversion unit 13, the first conductive line 14, the second conductive line 15, the relays 16, 17, the vehicle body 18, the reference conductive line 319, the control unit 20, and the in-vehicle cutoff device 330.

[0075] The reference conductive line 319 is electrically connected to the vehicle body 18. The reference conductive line 319 is electrically connected to the connection unit 12C of the charging inlet 12. In a state in which the counterpart connection unit 83 of the charging device 80 is connected to the connection unit 12C, the reference conductive line 319 is electrically connected to the protective ground line 87. Thus, the vehicle body 18 is electrically connected to the protective ground line 87.

[0076] The reference conductive line 319 has the first and second parallel conductive lines 319A, 319B. The first and second parallel conductive lines 319A, 319B are provided in parallel with each other between the vehicle body 18 and the connection unit 12C. The first parallel conductive line 319A is short-circuited to the vehicle body 18 and the connection unit 12C.

[0077] The in-vehicle cutoff device 330 is a device for the vehicle 310. The in-vehicle cutoff device 330 has the cutoff unit 31, the current detection unit 332, the overcurrent detection circuit 33, the drive circuit 34, the signal insulation unit 35, and the resistance unit 36.

[0078] The resistance unit 36 is provided to the second parallel conductive line 319B. That is, the resistance value of the second parallel conductive line 319B is greater than the resistance value of the first parallel conductive line 319A.

[0079] The current detection section 332 detects the current flowing in the reference conductive line 319 (more specifically, the second parallel conductive line 319B). The current detection section 232 can be a non-contact type configured in a non-contact manner with the second parallel conductive line 319B, or a contact type configured in a contact manner with the second parallel conductive line 319B. The non-contact type is constituted by, for example, a magnetic sensor such as a Hall element. The contact type is constituted by, for example, a shunt resistor and a differential amplifier that amplifies and outputs a voltage across the shunt resistor.

[0080] The in-vehicle cutoff device 330 is set to an operable state, for example, regardless of whether the charging device 80 is connected to the charging inlet 12. The current detection section 332 continuously detects the current flowing in the second parallel conductive line 319B and outputs a signal indicating the detected value. The overcurrent detection circuit 33 continuously determines whether the current flowing in the second parallel conductive line 319B exceeds a threshold value. The overcurrent detection circuit 33 outputs an overcurrent signal in a case where it is determined that the value of the current flowing in the second parallel conductive line 319B exceeds the threshold value. The signal insulation section 35 outputs the overcurrent signal input from the overcurrent detection circuit 33 side to the drive circuit 34 side. The drive circuit 34 provides a drive signal to the input section 31A of the cutoff section 31 in a case where the overcurrent signal is input. The cutoff section 31 switches to a cutoff state in accordance with the drive signal being provided to the input section 31A. Thus, the current flowing in the first conductive line 14 is cut off.

[0081] The following description relates to the effect of the in-vehicle cutoff device 330 of the third embodiment. In a configuration in which the current detection section 332 detects the current flowing in the reference conductive line 319, the reference conductive line 319 is likely to be long and the resistance value of the reference conductive line 319 is likely to be large in a case where the current detection section 332 is disposed close to the current detection section 332, the overcurrent detection circuit 33, the drive circuit 34, and the cutoff section 31. If the resistance value of the reference conductive line 319 is large, the current is less likely to be released to the protective ground line 87 at the time of occurrence of a ground fault. According to the in-vehicle cutoff device 330, the reference conductive line 319 is constituted by the first parallel conductive line 319A and the second parallel conductive line 319B disposed in parallel to each other, and thus the resistance value of the reference conductive line 319 is likely to be reduced.

[0082] The current detection section 332 of the in-vehicle cutoff device 330 detects the current suppressed by the resistance section 36, and thus it is easy to downsize the current detection section 332.

[0083] <Fourth Embodiment>

[0084] In the fourth embodiment, an example in which the current detection section is configured using the resistance section explained in the third embodiment will be explained. In the explanation of the fourth embodiment, the same reference numerals are assigned to the same structures as those of the second embodiment, and detailed explanation will be omitted.

[0085] In Figure 4 A vehicle 410 and a charging device 80 including the cut-off device for vehicle 430 of the fourth embodiment are disclosed. The vehicle 410 is provided with a battery 11, a charging inlet 12, a voltage conversion section 13, a first conductive line 14, a second conductive line 15, relays 16, 17, a vehicle body 18, a reference conductive line 419, a control section 20, and the cut-off device for vehicle 430.

[0086] The reference conductive line 419 is electrically connected to the vehicle body 18. The reference conductive line 419 is electrically connected to the connection section 12C of the charging inlet 12. In a state in which the counterpart connection section 83 of the charging device 80 is connected to the connection section 12C, the reference conductive line 419 is electrically connected to the protective ground line 87. Thus, the vehicle body 18 is electrically connected to the protective ground line 87.

[0087] The reference conductive line 419 has a first parallel conductive line 419A and a second parallel conductive line 419B. The first parallel conductive line 419A and the second parallel conductive line 419B are provided in parallel to each other between the vehicle body 18 and the connection section 12C. The first parallel conductive line 419A is short-circuited to the vehicle body 18 and the connection section 12C.

[0088] The cut-off device for vehicle 430 is a device for the vehicle 410. The cut-off device for vehicle 430 has a cut-off section 31, a current detection section 432, an overcurrent detection circuit 33, a drive circuit 34, and a signal insulation section 35.

[0089] The current detection section 432 detects a current flowing in the reference conductive line 419 (more specifically, the second parallel conductive line 419B). The current detection section 432 has a resistance section 436 and a differential amplification circuit 437. The resistance section 436 is provided to the second parallel conductive line 419B. That is, the resistance value of the second parallel conductive line 419B is larger than that of the first parallel conductive line 419A. The differential amplification circuit 437 amplifies and outputs a voltage across the resistance section 436. A signal output from the differential amplification circuit 437 is input to the overcurrent detection circuit 33.

[0090] The in-vehicle cutoff device 430 is set to an operable state, for example, regardless of whether the charging device 80 is connected to the charging inlet 12. The current detection section 432 continuously detects the current flowing in the second parallel conductive line 419B and outputs a signal indicating the detected value. The overcurrent detection circuit 33 continuously determines whether the current flowing in the second parallel conductive line 419B exceeds a threshold value. The overcurrent detection circuit 33 outputs an overcurrent signal in a case where it is determined that the value of the current flowing in the second parallel conductive line 419B exceeds the threshold value. The signal insulation section 35 outputs the overcurrent signal input from the overcurrent detection circuit 33 side to the drive circuit 34 side. The drive circuit 34 provides a drive signal to the input section 31A of the cutoff section 31 in a case where the overcurrent signal is input. The cutoff section 31 switches to a cutoff state in accordance with the drive signal provided to the input section 31A. Thus, the current flowing in the first conductive line 14 is cutoff.

[0091] The following description relates to the effect of the in-vehicle cutoff device 430 of the fourth embodiment. According to the in-vehicle cutoff device 430, the reference conductive line 419 is constituted by the first parallel conductive line 419A and the second parallel conductive line 419B arranged in parallel to each other, and thus it is easy to reduce the resistance value of the reference conductive line 419.

[0092] The current detection section 432 of the in-vehicle cutoff device 430 can detect the current using the resistance section 436 provided to the second parallel conductive line 419B.

[0093] <5th Embodiment>

[0094] In the fifth embodiment, a structure in which the case where an overcurrent state is detected by the overcurrent detection circuit is notified to the external ECU is described. In addition, in the description of the fifth embodiment, the same reference numerals are assigned to the same structures as those of the first embodiment, and detailed description is omitted.

[0095] In Figure 5 A vehicle 510 and the charging device 80 including the in-vehicle cutoff device 530 of the fifth embodiment are disclosed in the above. The vehicle 510 is provided with the battery 11, the charging inlet 12, the voltage conversion section 13, the first conductive line 14, the second conductive line 15, the relays 16, 17, the vehicle body 18, the reference conductive line 19, the control section 20, the in-vehicle cutoff device 530, and the external ECU 40.

[0096] The in-vehicle cutoff device 530 is a device for the vehicle 510. The in-vehicle cutoff device 530 has the cutoff section 31, the current detection section 32, the overcurrent detection circuit 33, the drive circuit 34, and the communication section 38.

[0097] The communication section 38 is a communication interface that communicates with an external ECU. The communication section 38 can receive the overcurrent signal output from the overcurrent detection circuit 33. The communication section 38 notifies the external ECU 40 of the fact that the overcurrent signal has been received. Thus, the in-vehicle cutout device 530 can report to the outside that the overcurrent state has occurred.

[0098] <Other Embodiments>

[0099] The present disclosure is not limited to the embodiments described above and illustrated in the drawings. For example, features of the above-described or hereinafter-described embodiments can be combined in any manner without contradiction. In addition, any feature of the above-described or hereinafter-described embodiments can be omitted if it is not explicitly stated as a necessary feature. Furthermore, the above-described embodiments can be changed in the following manner.

[0100] In the above-described second embodiment, the structure in which the first conductive line 14 is insulated from the reference conductive line 19 via the current detection section 232, the overcurrent detection circuit 33, the drive circuit 34, and the cutout section 31 can be another structure. For example, the signal insulation section 35 can be provided between the current detection section 232 and the overcurrent detection circuit 33, or between the overcurrent detection circuit 33 and the cutout section 31. As another example, the current detection section 232 can be a non-contact type in which the reference conductive line 19 is disposed in a non-contact manner. The non-contact type is constituted by a magnetic sensor such as a Hall element, for example. As another example, it can be a structure in which the input section 31A of the cutout section 31 is insulated from the first conductive line 14, like a pyrotechnic circuit breaker. As another example, it can be a structure in which a step-up transformer is provided between the drive circuit 34 and the cutout section 31. The step-up transformer steps up the voltage input from the drive circuit 34 side and applies it to the input section 31A of the cutout section 31. In addition, the first conductive line 14 can be insulated from the reference conductive line 19 via the current detection section 232, the overcurrent detection circuit 33, the drive circuit 34, and the cutout section 31 by a combination of these structures. The same applies to the above-described third and fourth embodiments.

[0101] In each of the above-described embodiments, the cutout section 31 is provided to the first negative-side conductive line 14B, but it can be provided to the first positive-side conductive line 14A, or to both the first positive-side conductive line 14A and the first negative-side conductive line 14B.

[0102] In each of the above-described embodiments, the power supplied from the charging inlet 12 to the battery 11 must be voltage-converted by the voltage conversion section 13, but a bypass line that bypasses the voltage conversion section 13 can be provided and the power can be supplied to the battery 11 via the bypass line.

[0103] It should be understood that the embodiments disclosed herein are illustrative and not restrictive, the scope of the application is not limited to the embodiments disclosed herein, but is indicated by the claims, and is intended to include all modifications equivalent within the meaning and scope of the claims.

[0104] BRIEF DESCRIPTION OF DRAWINGS

[0105] 10 vehicle

[0106] 11 battery

[0107] 12 charging inlet

[0108] 12A first terminal

[0109] 12B second terminal

[0110] 12C connecting portion

[0111] 13 voltage conversion portion

[0112] 14 first conductive line

[0113] 14A first positive electrode side conductive line

[0114] 14B first negative electrode side conductive line

[0115] 15 second conductive line

[0116] 15A second positive electrode side conductive line

[0117] 15B second negative electrode side conductive line

[0118] 16 relay

[0119] 17 relay

[0120] 18 vehicle body

[0121] 19 reference conductive line

[0122] 20 control portion

[0123] 30 on-vehicle cut-off device

[0124] 31 cut-off portion

[0125] 31A input portion

[0126] 32 current detection portion

[0127] 33 overcurrent detection circuit

[0128] 34 drive circuit

[0129] 35 signal insulation portion

[0130] 36 … resistor section

[0131] 38 … communication section

[0132] 40 … external ECU

[0133] 80 … charging device

[0134] 81 … first counterpart-side terminal

[0135] 82 … second counterpart-side terminal

[0136] 83 … counterpart-side connecting section

[0137] 84 … charger

[0138] 85 … positive-side supply line

[0139] 86 … negative-side supply line

[0140] 87 … protective ground line

[0141] 88 … first SPD

[0142] 89 … second SPD

[0143] 210 … vehicle

[0144] 230 … on-vehicle cutoff device

[0145] 232 … current detection section

[0146] 310 … vehicle

[0147] 319 … reference conductive line

[0148] 319A … first parallel conductive line

[0149] 319B … second parallel conductive line

[0150] 330 … on-vehicle cutoff device

[0151] 332 … current detection section

[0152] 410 … vehicle

[0153] 419 … reference conductive line

[0154] 419A … first parallel conductive line

[0155] 419B … second parallel conductive line

[0156] 430 … on-vehicle cutoff device

[0157] 432 … current detection section

[0158] 436 … resistance section

[0159] 437 … differential amplifier circuit

[0160] 510 … vehicle

[0161] 530 … in-vehicle cutting device

Claims

1. A cut-off device for a vehicle, for a vehicle provided with: a battery; a charging inlet connected to a charging device outside the vehicle; a voltage conversion section that converts a voltage input from the charging inlet side and outputs to the battery side. A conductive line is provided between the charging inlet and the voltage conversion section, and a reference conductive line is electrically connected to the vehicle body. The charging inlet has a connection section that connects the reference conductive line and a protective ground line of the charging device. In this case, The vehicle-mounted cutoff device has: a cutoff section provided in the conductive line and configured to switch from a permitted state in which current is permitted to flow through the conductive line to a cutoff state in accordance with input of a drive signal to an input section; a current detection section configured to detect current flowing through the conductive line or the reference conductive line; an overcurrent detection circuit configured to detect an overcurrent state based on a detection result of the current detection section; and a drive circuit configured to supply the drive signal to the input section of the cutoff section in a case where the overcurrent state is detected by the overcurrent detection circuit.

2. The vehicle-mounted cutoff device according to claim 1, wherein the current detection section detects current flowing through the reference conductive line.

3. The vehicle-mounted cutoff device according to claim 2, wherein the conductive line and the reference conductive line are insulated from each other via the current detection section, the overcurrent detection circuit, the drive circuit, and the cutoff section.

4. The vehicle-mounted cutoff device according to claim 3, wherein the vehicle-mounted cutoff device has a signal insulation section provided in at least any one of between the current detection section and the overcurrent detection circuit, between the overcurrent detection circuit and the drive circuit, and between the drive circuit and the cutoff section, for insulating and transmitting signals.

5. The vehicle-mounted cutoff device according to any one of claims 2 to 4, wherein the reference conductive line has a first parallel conductive line and a second parallel conductive line that are provided in parallel with each other between the vehicle body and the connection section.

6. The vehicle-mounted cutoff device according to claim 5, wherein the first parallel conductive line is short-circuited to the vehicle body and the connection section, a resistance section is provided in the second parallel conductive line, the current detection section detects current flowing through the second parallel conductive line.

7. The vehicle-mounted cutoff device according to claim 6, wherein the current detection section has: the resistance section; and a differential amplification circuit that amplifies and outputs a voltage across the resistance section.

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