Abnormality detection device

Abstract

An abnormality detection device (10) is used in a supply system (100) provided with a power supply unit (90), and a first power line (92) and a second power line (93) provided between the power supply unit (90) and a fire circuit breaker (91). The abnormality detection device (10) is provided with a first switch (10A) of a first power line (92), a second switch (10B) of a second power line (93), a first resistor part (10C) and a second resistor part (10D), and a detection part (10E), and the first resistor part (10C) is electrically connected with a first part (B1) between a power supply part (90) and the first switch (10A) and a second part (B2) between the second switch (10B) and a pyrotechnic circuit breaker (91). The second resistor part (10D) is electrically connected to the second part (B2) and a third part (B3) between the second switch (10B) and the power supply part (90), and the detection part (10E) detects the voltage state of the second part (B2) when at least one of the first switch (10A) and the second switch (10B) is in an off state.

Description

Technical Field

[0001] The present disclosure relates to an abnormality detection device. Background Art

[0002] The following technique is disclosed in Patent Document 1: A test current is passed through a detonator in an ignition device of an airbag, and a change in resistance value caused by a poor connection or deterioration of the detonator is detected.

[0003] Prior Art Documents Patent Documents Patent Document 1: Japanese Patent Laid-Open No. 6-72281 Summary of the Invention

[0004] Problems to be Solved by the Invention

[0005] However, in order to confirm whether the airbag can operate normally, it is preferable to confirm not only the detonator but also that the switch through which the ignition current flows is normal, that the path from the power supply to the detonator is not broken, and that the power supply voltage is normal. In addition, the same can be said about the operation of the initiator of the pyrotechnic fuse that cuts off the power path.

[0006] The present disclosure has been made based on the above circumstances, and an object thereof is to provide an abnormality detection device that can detect an abnormality generated in a path from a power supply unit to a power supply target.

[0007] Means for Solving the Problems

[0008] The abnormality detection device of the present disclosure is used in a supply system, The supply system includes: a power supply unit that supplies power; a first power line provided between a high-potential side terminal of the power supply unit and a power supply target; and a second power line provided between a low-potential side terminal of the power supply unit and the power supply target, The abnormality detection device includes: a first switch provided in the first power line; a second switch provided in the second power line; a first resistor portion and a second resistor portion that constitute a conduction path; and a detection unit that detects a voltage state, When the first switch is in the ON state, energization through the first switch is allowed, and when the first switch is in the OFF state, energization through the first switch is cut off, When the second switch is in the ON state, energization through the second switch is allowed, and when the second switch is in the OFF state, energization through the second switch is cut off, One end of the first resistor portion is electrically connected to a first portion between the power supply portion and the first switch in the first power line, and the other end of the first resistor portion is electrically connected to a second portion between the second switch and the power supply object in the second power line. One end of the second resistor portion is electrically connected to the second portion, and the other end of the second resistor portion is electrically connected to a third portion between the second switch and the power supply portion in the second power line. The detection unit detects the voltage state of the second portion when controlling at least one of the first switch and the second switch to be in an off state.

[0009] Advantages of the Invention

[0010] According to the present disclosure, it is possible to detect an abnormality generated in the path from the power supply portion to the power supply object. Description of the Drawings

[0011] Figure 1 It is a circuit diagram illustrating an abnormality detection device according to Embodiment 1. Figure 2 It is a schematic diagram showing the structure of a pyrotechnic circuit breaker. Figure 3 It is a flowchart illustrating an example of the determination operation of the detection unit of the abnormality detection device according to Embodiment 1. Figure 4 It is a circuit diagram illustrating an abnormality detection device according to Embodiment 2. Figure 5 It is a flowchart illustrating an example of the determination operation of the detection unit of the abnormality detection device according to Embodiment 2. Detailed Embodiments

[0012] [Description of Embodiments of the Present Disclosure]

[0013] First, embodiments of the present disclosure will be listed and described.

[0014] 〔1〕The abnormality detection device of the present disclosure is used in a power supply system, which includes: a power supply unit that supplies power; a first power line provided between the high-potential side terminal of the power supply unit and the power supply object; and a second power line provided between the low-potential side terminal of the power supply unit and the power supply object. The abnormality detection device of the present disclosure includes: a first switch provided in the first power line; a second switch provided in the second power line; a first resistor portion and a second resistor portion that constitute a conduction path; and a detection unit that detects the voltage state. When the first switch is in the closed state, power conduction through the first switch is allowed, and when the first switch is in the open state, power conduction through the first switch is cut off. When the second switch is in the closed state, power conduction through the second switch is allowed, and when the second switch is in the open state, power conduction through the second switch is cut off. One end of the first resistor portion is electrically connected to a first portion between the power supply unit and the first switch in the first power line, and the other end of the first resistor portion is electrically connected to a second portion between the second switch and the power supply object in the second power line. One end of the second resistor portion is electrically connected to the second portion, and the other end of the second resistor portion is electrically connected to a third portion between the second switch and the power supply unit in the second power line. The detection unit detects the voltage state of the second portion when at least one of the first switch and the second switch is controlled to be in the open state.

[0015] The abnormality detection device described in the above 〔1〕 can perform the following operation: in a state where power is not supplied from the power supply unit to the power supply object, the detection unit detects the voltage state of the second portion and determines an abnormality in the power supply system based on the detected voltage state.

[0016] 〔2〕In the abnormality detection device described in the above 〔1〕, the power supply object may have a pyrotechnic circuit breaker, and the pyrotechnic circuit breaker is provided in a specified conduction path. The pyrotechnic circuit breaker has a conductor portion that shorts the first conduction path and the second conduction path of the conduction path, and the pyrotechnic circuit breaker can explode to cut off the conductor portion when a specified current flows between the first power line and the second power line.

[0017] In the abnormality detection device described in the above 〔2〕, the pyrotechnic circuit breaker cuts off the conduction path when it is driven. Therefore, by detecting the voltage of the second portion when at least one of the first switch and the second switch is made to be in the open state without driving the pyrotechnic circuit breaker, an abnormality in the power supply system can be determined.

[0018] 〔3〕In the abnormality detection device of the above 〔1〕 or 〔2〕, the detection unit can determine whether the voltage of the second part is within an abnormal range when a disconnection instruction is issued to the first switch and the second switch. The abnormal range can include at least any one of a voltage range equal to or lower than a first threshold smaller than the first normal voltage and a voltage range equal to or higher than a second threshold larger than the first normal voltage. The first normal voltage is the voltage of the second part when the first switch and the second switch are normally in the off state.

[0019] In the abnormality detection device of the above 〔3〕, the magnitude of the voltage of the second part when the first switch and the second switch are normally in the on state becomes a value obtained by dividing the output voltage of the high potential side of the power supply unit by the first resistor unit and the second resistor unit. By comparing the first threshold and the second threshold based on this value with the actual voltage value of the second part, it is possible to detect a decrease or increase in the power supply voltage, disconnection of the first power line and the second power line, and short - circuit faults of the first switch and the second switch.

[0020] 〔4〕In the abnormality detection device of the above 〔1〕 or 〔2〕, the detection unit can determine whether the voltage of the second part is within an abnormal range when a connection instruction is issued to the first switch and a disconnection instruction is issued to the second switch. The abnormal range can include at least any one of a voltage range equal to or lower than a third threshold smaller than the second normal voltage and a voltage range equal to or higher than a fourth threshold larger than the second normal voltage. The second normal voltage can be the voltage of the second part when the first switch is normally in the on state and the second switch is normally in the off state.

[0021] In the abnormality detection device of the above 〔4〕, when the first switch is normally in the on state, the second switch is normally in the off state, and the resistance value of the power supply object is normal, the voltage of the second part becomes a value obtained by dividing the output voltage of the high potential side of the power supply unit by a combined resistor formed by connecting the power supply object in parallel with the first resistor unit and the second resistor unit. By comparing the third threshold and the fourth threshold based on this value with the actual voltage value of the second part, it is possible to detect an open - circuit fault of the first switch, a poor connection of the power supply object, and a change in the resistance value of the power supply object.

[0022] 〔5〕In the abnormality detection device of the above 〔1〕 or 〔2〕, the detection unit can determine whether the voltage of the second part is within an abnormal range when a disconnection instruction is issued to the first switch and a connection instruction is issued to the second switch. The abnormal range can include a voltage range equal to or higher than a fifth threshold larger than the third normal voltage. The third normal voltage is the voltage of the second part when the first switch is normally in the off state and the second switch is normally in the on state.

[0023] When the first switch is normally in the off state and the second switch is normally in the on state in the above-mentioned abnormality detection device of [5], the voltage of the second part becomes the same value as the voltage on the low-potential side of the power supply unit. By comparing the fifth threshold value based on this value with the actual voltage value of the second part, an open-circuit fault of the second switch can be detected.

[0024] 〔6〕The abnormality detection device of the above-mentioned [1] or [2] may be such that the abnormality detection device includes a series structure part formed by connecting a third switch and a third resistor part in series. One end of the series structure part is electrically connected to the third part, and the other end of the series structure part is electrically connected to the second part.

[0025] By further increasing the series structure part formed by connecting the third switch and the third resistor part in series in the abnormality detection device of the above-mentioned [6], abnormalities in the supply system can be judged more carefully.

[0026] 〔7〕In the abnormality detection device of the above-mentioned [6], the detection part can judge whether the voltage of the second part is within the abnormal range when a disconnection instruction is issued to the first switch, the second switch, and the third switch. The abnormal range can include at least one of the voltage ranges below the first threshold value smaller than the first normal voltage and the voltage ranges above the second threshold value larger than the first normal voltage. The first normal voltage may be the voltage of the second part when the first switch, the second switch, and the third switch are normally in the off state.

[0027] When the first switch, the second switch, and the third switch are normally in the off state in the abnormality detection device of the above-mentioned [7], the voltage of the second part becomes a value obtained by dividing the output voltage of the high-potential side of the power supply unit by the first resistor part and the second resistor part. By comparing the first threshold value and the second threshold value based on this value with the actual voltage value of the second part, a decrease or increase in the power supply voltage, disconnection of the first power line and the second power line, and short-circuit faults of the first switch and the second switch can be detected.

[0028] 〔8〕In the abnormality detection device of the above-mentioned [6], the detection part can judge whether the voltage of the second part is within the abnormal range when a connection instruction is issued to the first switch and the third switch and a disconnection instruction is issued to the second switch. The abnormal range can include at least one of the voltage ranges below the third threshold value smaller than the second normal voltage and the voltage ranges above the fourth threshold value larger than the second normal voltage. The second normal voltage may be the voltage of the second part when the first switch and the third switch are normally in the on state and the second switch is normally in the off state.

[0029] In the abnormality detection device of the above [8], when the first switch and the third switch are normally in the on state, the second switch is normally in the off state, and the resistance value of the power supply object is normal, the voltage of the second part becomes a value obtained by dividing the output voltage of the high potential side of the power supply unit by the combined resistance formed by connecting the power supply object in parallel with the first resistance part and the combined resistance formed by connecting the second resistance part in parallel with the third resistance part. By comparing the third threshold and the fourth threshold based on this value with the actual voltage value of the second part, it is possible to detect an open circuit fault of the first switch, a poor connection of the power supply object, and a change in the resistance value of the power supply object.

[0030] [9] In the abnormality detection device of the above [6], the detection unit can determine whether the voltage of the second part is within an abnormal range when a disconnection instruction is issued to the first switch and the third switch and a connection instruction is issued to the second switch. The abnormal range can include a voltage range of the fifth threshold or more that is larger than the third normal voltage, and the third normal voltage is the voltage of the second part when the first switch and the third switch are normally in the off state and the second switch is normally in the on state.

[0031] In the abnormality detection device of the above [9], when the first switch and the third switch are normally in the off state and the second switch is normally in the on state, the voltage of the second part becomes the same value as the voltage of the low potential side of the power supply unit. By comparing the fifth threshold based on this value with the actual voltage value of the second part, it is possible to detect an open circuit fault of the second switch.

[0032]

[10] In the abnormality detection device of the above [6], the value obtained by dividing the voltage of the high potential side of the power supply unit by the first resistance part and the second resistance part can be the same as the value obtained by dividing the voltage of the high potential side of the power supply unit by the third resistance part and the power supply object.

[0033] In the abnormality detection device of the above

[10] , the first normal voltage that is the reference for the first threshold and the second threshold can be the same as the second normal voltage that is the reference for the third threshold and the fourth threshold. Therefore, when the detection unit is composed of a comparator, the number of comparators to be set can be suppressed.

[0034] [Details of the Embodiment of the Present Disclosure]

[0035] [Embodiment 1]

[0036] [Outline of the Supply System]

[0037] Figure 1The supply system 100 shown is a system mounted on a vehicle. The supply system 100 includes a power supply unit 90, a pyrotechnic circuit breaker 91 that is an object of power supply, and an abnormality detection device 10. The power supply unit 90 uses, for example, a lead-acid battery, a lithium-ion battery, etc. A high-potential side terminal and a low-potential side terminal are provided in the power supply unit 90. The output voltage of the power supply unit 90 (the potential difference between the high-potential side terminal and the low-potential side terminal) is Vo. The voltage of the low-potential side terminal of the power supply unit 90 is a reference potential, for example, a ground potential maintained at 0V. One end of a first power line 92 is electrically connected to the high-potential side terminal of the power supply unit 90. One end of a second power line 93 is electrically connected to the low-potential side terminal of the power supply unit 90. The first power line 92 and the second power line 93 are paths for transmitting power.

[0038] The pyrotechnic circuit breaker 91 uses, for example, a pyrotechnic fuse (PYROFUSE (registered trademark)). The pyrotechnic circuit breaker 91 is provided between the first power line 92 and the second power line 93. As Figure 2 shown, the pyrotechnic circuit breaker 91 has an initiator 91C, gunpowder 91F, a displacement part 91D, and a conductor part 91E.

[0039] The initiator 91C is electrically connected to the other end of the first power line 92 and the other end of the second power line 93. The first power line 92 and the second power line 93 are provided between the power supply unit 90 and the initiator 91C. The initiator 91C is configured to generate heat when a prescribed current flows between the first power line 92 and the second power line 93 after the first switch 10A and the second switch 10B described later are switched from the off state to the on state. The initiator 91C has a resistance value of size Ri. The gunpowder 91F is provided adjacent to the initiator 91C. The gunpowder 91F explodes when receiving the heat generated in the initiator 91C, generating an explosive force. That is, the initiator 91C performs an explosive action of igniting the gunpowder 91F according to the situation of power supply from the power supply unit 90. The gunpowder 91F generates an explosive force when ignited. The displacement part 91D is provided adjacent to the gunpowder 91F. The displacement part 91D rapidly displaces when receiving the explosive force generated from the exploding gunpowder 91F.

[0040] The conductor part 91E is formed of, for example, a strip-shaped metal having conductivity. The conductor part 91E is electrically connected in such a manner that the first conduction path W1 and the second conduction path W2 of the prescribed conduction path W are short-circuited. The conductor part 91E is disposed on the opposite side of the gunpowder 91F with the displacement part 91D interposed therebetween. The conductor part 91E is physically cut within an extremely short time by the displacement part 91D that is rapidly displaced by the explosive force generated by the explosion action. Thereby, the conductor part 91E cuts off the conduction path W when itself is cut off. The cut-off conductor part 91E does not reconnect. That is, the pyrotechnic circuit breaker 91 is a fuse device that cuts off the conductor part 91E by the displacement of the displacement part 91D corresponding to the explosion action.

[0041] In the present disclosure, "electrically connected" preferably has a structure in which conduction is achieved in such a manner that the potentials of both connection objects are equal (a state in which current flows). However, it is not limited to this structure. For example, "electrically connected" may also be a structure in which an electrical component is sandwiched between two connection objects and the two connection objects are connected in a state where conduction is possible. In the present disclosure, "short-circuit" refers to a structure in which conduction is achieved in such a manner that the potentials of both connection objects are equal (a state in which current flows) in the "electrically connected" manner.

[0042] As Figure 1 shown, the abnormality detection device 10 includes a first switch 10A, a second switch 10B, a first resistor part 10C, a second resistor part 10D, and a detection part 10E. The first switch 10A is interposed in the first power line 92. The second switch 10B is interposed in the second power line 93. The first switch 10A and the second switch 10B have a function of switching between an on state and an off state. When the first switch 10A and the second switch 10B are switched to the on state, energization via the first switch 10A and the second switch 10B is permitted. Then, the first power line 92 and the second power line 93 can be energized between the power supply unit 90 and the pyrotechnic circuit breaker 91, respectively.

[0043] When the first switch 10A and the second switch 10B are switched to the off state, the energization via the first switch 10A and the second switch 10B is cut off. Then, the energization between the power supply unit 90 and the pyrotechnic circuit breaker 91 is cut off for the first power line 92 and the second power line 93, respectively. The first switch 10A and the second switch 10B use, for example, relay switches such as semiconductor relays and mechanical relays.

[0044] The first resistor section 10C and the second resistor section 10D use resistors having two terminals. The resistance value of the first resistor section 10C is R1, and the resistance value of the second resistor section 10D is R2. One end of the first resistor section 10C is electrically connected to a first part B1 in a first power line 92 between the power supply section 90 and the first switch 10A. The other end of the first resistor section 10C is electrically connected to a second part B2 in a second power line 93 between the second switch 10B and the pyrotechnic circuit breaker 91. The first resistor section 10C forms a conduction path between the first part B1 and the second part B2. One end of the second resistor section 10D is electrically connected to the second part B2 in the second power line 93 between the second switch 10B and the pyrotechnic circuit breaker 91. The other end of the second resistor section 10D is electrically connected to a third part B3 in the second power line 93 between the second switch 10B and the power supply section 90. The second resistor section 10D forms a conduction path between the second part B2 and the third part B3. In order to suppress dark current, the resistance value R1 and the resistance value R2 are preferably sufficiently large values.

[0045] The detection section 10E is constituted mainly by, for example, a microcomputer, and includes an arithmetic device such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), an A / D converter, etc. The detection section 10E is electrically connected to the second part B2 in the second power line 93 to which the other end of the second resistor section 10D is electrically connected. It is configured to input the voltage value V applied to the second part B2 to the detection section 10E, and be able to detect the voltage state of the second part B2.

[0046] In the ROM or the like of the detection section 10E, a first threshold Th1, a second threshold Th2, a third threshold Th3, a fourth threshold Th4, and a fifth threshold Th5 are stored. The detection section 10E has a function of comparing the voltage value V of the second part B2 with the first threshold Th1, the second threshold Th2, the third threshold Th3, the fourth threshold Th4, and the fifth threshold Th5 to determine whether the voltage of the second part B2 is in an abnormal state.

[0047] The first threshold Th1 and the second threshold Th2 are based on the first normal voltage Vd1, which is the voltage of the second part B2 when the first switch 10A and the second switch 10B are normally in the off state. Here, the first normal voltage Vd1 is a value obtained by dividing the output voltage Vo of the power supply unit 90 by the first resistor unit 10C (resistance value R1) and the second resistor unit 10D (resistance value R2), and is represented by the following formula 1. For example, the output voltage Vo of the power supply unit 90 is the potential difference between the high-potential side terminal and the low-potential side terminal of the power supply unit 90 when the power supply unit 90 is in the fully charged state. And the first normal voltage Vd1 is the voltage value obtained when the power supply unit 90 is in the fully charged state.

[0048] [Mathematical formula 1]

[0049]

[0050] The first threshold Th1 is smaller than the first normal voltage Vd1 by a specified value. The second threshold Th2 is larger than the first normal voltage Vd1 by a specified value. The values of the first threshold Th1 and the second threshold Th2 can be changed to desired magnitudes according to desired specifications.

[0051] The third threshold Th3 and the fourth threshold Th4 are based on the second normal voltage Vd2, which is the voltage of the second part B2 when the first switch 10A is normally in the on state and the second switch 10B is normally in the off state. The second normal voltage Vd2 is the voltage value obtained when the power supply unit 90 is in the fully charged state. Here, the second normal voltage Vd2 is a value obtained by dividing the voltage by the first resistor unit 10C (resistance value R1) and the trigger 91C (resistance value Ri) connected in parallel and the second resistor unit 10D (resistance value R2), and is represented by the following formula 2.

[0052] [Mathematical formula 2]

[0053]

[0054] The third threshold Th3 is smaller than the second normal voltage Vd2 by a specified value. The fourth threshold Th4 is larger than the second normal voltage Vd2 by a specified value. The values of the third threshold Th3 and the fourth threshold Th4 can be changed to desired magnitudes according to desired specifications.

[0055] The fifth threshold Th5 is based on the third normal voltage Vd3, which is the voltage of the second part B2 when the first switch 10A is normally in the off state and the second switch 10B is normally in the on state. The third normal voltage Vd3 becomes the same voltage as the low-potential side terminal of the power supply unit 90 (ground potential). The fifth threshold Th5 is larger than the third normal voltage Vd3 (ground potential) by a specified value. The value of the fifth threshold Th5 can be changed to a desired magnitude according to the desired specifications.

[0056] Moreover, the detection unit 10E can execute control to separately switch the first switch 10A and the second switch 10B between the off state and the on state. Specifically, the detection unit 10E can perform first switching control, second switching control, and third switching control. The first switching control, second switching control, and third switching control are executed after the ignition switch of the vehicle is switched from the off state to the on state. The first switching control is control that issues an off instruction to the first switch 10A and the second switch 10B and maintains the first switch 10A and the second switch 10B in the off state. The second switching control is the following control: an on instruction is issued to the first switch 10A and the first switch 10A is maintained in the on state, an off instruction is issued to the second switch 10B and the second switch 10B is maintained in the off state. The third switching control is the following control: an off instruction is issued to the first switch 10A and the first switch 10A is maintained in the off state, an on instruction is issued to the second switch 10B and the second switch 10B is maintained in the on state.

[0057] 〔An example of the operation of the abnormality detection device〕

[0058] Next, an example of the operation of the abnormality detection device 10 will be described. In a vehicle equipped with the supply system 100, when the ignition switch is in the off state, the first switch 10A and the second switch 10B are set to the off state. In this case, Figure 3 in step S1 is "No", and the process ends Figure 3 processing. In step S1, if the ignition switch is switched from the off state to the on state ("Yes" in step S1), the process proceeds to step S2. In step S2, the detection unit 10E executes the first switching control, which issues an off instruction to the first switch 10A and the second switch 10B and maintains the first switch 10A and the second switch 10B in the off state.

[0059] The detection unit 10E obtains the voltage value V of the second part B2. In step S2, the detection unit 10E compares the voltage value V with the first threshold Th1 and the second threshold Th2 to determine whether the voltage of the second part B2 is within the abnormal range.

[0060] When the voltage value V is less than the first threshold Th1, it is presumed that the voltage of the second part B2 has dropped due to a disconnection of the first power line 92 between the first resistor part 10C and the power supply part 90 or a short-circuit fault of the second switch 10B. When the voltage value V is greater than the second threshold Th2, it is presumed that the voltage of the second part B2 has risen due to a disconnection of the second power line 93 between the second part B2 and the power supply part 90 or a short-circuit fault of the first switch 10A. Therefore, when the detection unit 10E determines that the voltage value V is less than the first threshold Th1 or the voltage value V is greater than the second threshold Th2 ( "No" in step S2), the process proceeds to step S6. When the process proceeds to step S6, the detection unit 10E determines that the supply system 100 is in an abnormal state and ends Figure 3 the processing. The abnormal range of the voltage of the second part B2 in step S2 includes at least one of the voltage ranges below the first threshold Th1 smaller than the first normal voltage Vd1 and above the second threshold Th2 larger than the first normal voltage Vd1. The first normal voltage Vd1 is the voltage of the second part B2 when the first switch 10A and the second switch 10B are normally in the off state. When the voltage value V is equal to or less than the second threshold Th2 and equal to or greater than the first threshold Th1 ( "Yes" in step S2), the process proceeds to step S3.

[0061] When the process proceeds to step S3, the detection unit 10E performs second switching control, which issues a turn-on instruction to the first switch 10A and maintains the first switch 10A in the on state, and issues a turn-off instruction to the second switch 10B and maintains the second switch 10B in the off state. Then, it is determined whether the voltage of the second part B2 is within the abnormal range. If the process proceeds to step S3, the detection unit 10E compares the voltage value V of the second part B2 with the third threshold Th3 and the fourth threshold Th4.

[0062] When the voltage value V is less than the third threshold Th3, it is presumed that the voltage of the second part B2 has dropped due to an open-circuit fault of the first switch 10A or an open circuit caused by a poor connection between the initiator 91C and the first power line 92. When the voltage value V is greater than the fourth threshold Th4, it is presumed that the voltage of the second part B2 has risen due to a change in the resistance value Ri caused by deterioration of the initiator 91C or a short circuit of the initiator 91C caused by a poor connection between the initiator 91C and the first power line 92. Therefore, when the detection unit 10E determines that the voltage value V is less than the third threshold Th3 or the voltage value V is greater than the fourth threshold Th4 ( "No" in step S3), the process proceeds to step S6. When the process proceeds to step S6, the detection unit 10E determines that the supply system 100 is in an abnormal state and ends Figure 3Processing in []. The abnormal range of the voltage of the second part B2 in step S3 includes at least any one of the voltage ranges below the third threshold Th3 smaller than the second normal voltage Vd2 and above the fourth threshold Th4 larger than the second normal voltage Vd2. The second normal voltage Vd2 is the voltage of the second part B2 when the first switch 10A is normally in the on state and the second switch 10B is normally in the off state. When the voltage value V is below the fourth threshold Th4 and above the third threshold Th3 ( "Yes" in step S3), it transfers to step S4.

[0063] When it transfers to step S4, the detection unit 10E executes third switching control, which issues a disconnection instruction to the first switch 10A and maintains the first switch 10A in the off state, and issues a connection instruction to the second switch 10B and maintains the second switch 10B in the on state. Then, it determines whether the voltage of the second part B2 is in the abnormal range. When it transfers to step S4, the detection unit 10E compares the voltage value V of the second part B2 with the fifth threshold Th5.

[0064] When the voltage value V is larger than the fifth threshold Th5, it is presumed that the voltage of the second part B2 has risen due to an open circuit fault of the second switch 10B. Therefore, if the detection unit 10E determines that the voltage value V is larger than the fifth threshold Th5 ( "No" in step S4), it transfers to step S6, and the detection unit 10E determines that the supply system 100 is in an abnormal state and ends Figure 3 Processing in []. When the voltage value V is below the fifth threshold Th5 ( "Yes" in step S4), it transfers to step S5. When it transfers to step S5, the detection unit 10E determines that the supply system 100 is in a normal state and ends Figure 3 Processing in []. The abnormal range of the voltage of the second part B2 in step S4 includes the voltage range above the fifth threshold Th5 larger than the third normal voltage Vd3. The third normal voltage Vd3 is the voltage of the second part B2 when the first switch 10A is normally in the off state and the second switch 10B is normally in the on state. In this way, the detection unit 10E detects the voltage state of the second part B2 when at least any one of the first switch 10A and the second switch 10B is controlled to be in the off state.

[0065] Next, the effects of this structure are illustrated.

[0066] The abnormality detection device 10 is used in the supply system 100, and the supply system 100 includes: a power supply unit 90 that supplies power; a first power line 92 disposed between the high-potential side terminal of the power supply unit 90 and the pyrotechnic circuit breaker 91; and a second power line 93 disposed between the low-potential side terminal of the power supply unit 90 and the pyrotechnic circuit breaker 91. It includes a first switch 10A disposed on the first power line 92, a second switch 10B disposed on the second power line 93, a first resistor section 10C and a second resistor section 10D that constitute a conduction path, and a detection section 10E that detects the voltage state. When the first switch 10A is in the on state, energization via the first switch 10A is permitted, and when the first switch 10A is in the off state, energization via the first switch 10A is cut off. When the second switch 10B is in the on state, energization via the second switch 10B is permitted, and when the second switch 10B is in the off state, energization via the second switch 10B is cut off. One end of the first resistor section 10C is electrically connected to a first portion B1 between the power supply unit 90 and the first switch 10A in the first power line 92. The other end of the first resistor section 10C is electrically connected to a second portion B2 between the second switch 10B and the pyrotechnic circuit breaker 91 in the second power line 93. One end of the second resistor section 10D is electrically connected to the second portion B2, and the other end of the second resistor section 10D is electrically connected to a third portion B3 between the second switch 10B and the power supply unit 90 in the second power line 93. The detection section 10E detects the voltage state of the second portion B2 when at least one of the first switch 10A and the second switch 10B is controlled to be in the off state.

[0067] According to this structure, the following operation can be performed: in a state where power is not supplied from the power supply unit 90 to the pyrotechnic circuit breaker 91, the detection section 10E detects the voltage state of the second portion B2, and based on the detected voltage state, an abnormality in the supply system 100 is determined.

[0068] In the abnormality detection device 10, the pyrotechnic circuit breaker 91 is disposed on a prescribed conductive path W. The pyrotechnic circuit breaker 91 has a conductor portion 91E that short-circuits a first conductive path W1 and a second conductive path W2 of the conductive path W, and generates an explosion to cut off the conductor portion 91E when a prescribed current flows between the first power line 92 and the second power line 93. According to this structure, the pyrotechnic circuit breaker 91 cuts off the conductive path W during driving. Therefore, by detecting the voltage of the second portion B2 when at least one of the first switch 10A and the second switch 10B is made to be in the off state and the pyrotechnic circuit breaker is not driven, an abnormality in the supply system 100 can be determined.

[0069] In the abnormality detection device 10, when the detection unit 10E issues a disconnection instruction to the first switch 10A and the second switch 10B, it determines whether the voltage of the second part B2 is within the abnormal range. The abnormal range includes at least any one of the voltage ranges below the first threshold Th1 smaller than the first normal voltage Vd1 and above the second threshold Th2 larger than the first normal voltage Vd1. The first normal voltage Vd1 is the voltage of the second part B2 when the first switch 10A and the second switch 10B are normally in the open state. According to this structure, the voltage of the second part B2 when the first switch 10A and the second switch 10B are normally in the closed state becomes the first normal voltage Vd1 obtained by dividing the output voltage Vo of the high potential side of the power supply unit 90 by the first resistor unit 10C and the second resistor unit 10D. By comparing the first threshold Th1 and the second threshold Th2 based on this value with the actual voltage value V of the second part B2, it is possible to detect a decrease or increase in the power supply voltage, a disconnection of the first power line 92 and the second power line 93, and a short circuit fault of the first switch 10A and the second switch 10B.

[0070] In the abnormality detection device 10, when the detection unit 10E issues a connection instruction to the first switch 10A and a disconnection instruction to the second switch 10B, it determines whether the voltage of the second part B2 is within the abnormal range. The abnormal range includes at least any one of the voltage ranges below the third threshold Th3 smaller than the second normal voltage Vd2 and above the fourth threshold Th4 larger than the second normal voltage Vd2. The second normal voltage Vd2 is the voltage of the second part B2 when the first switch 10A is normally in the connected state and the second switch 10B is normally in the open state. According to this structure, when the first switch 10A is normally in the connected state, the second switch 10B is normally in the open state, and the resistance value Ri of the initiator 91C of the pyrotechnic circuit breaker 91 is normal, the voltage of the second part B2 becomes the value obtained by dividing the output voltage Vo of the high potential side of the power supply unit 90 by the combined resistor formed by connecting the initiator 91C and the first resistor unit 10C in parallel and the second resistor unit 10D. By comparing the third threshold Th3 and the fourth threshold Th4 based on this value with the actual voltage value V of the second part B2, it is possible to detect an open circuit fault of the first switch 10A, a poor connection of the pyrotechnic circuit breaker 91, and a change in the resistance value Ri of the initiator 91C of the pyrotechnic circuit breaker 91.

[0071] In the abnormality detection device 10, the detection unit 10E determines whether the voltage of the second part B2 is within an abnormal range when an off instruction is issued to the first switch 10A and an on instruction is issued to the second switch 10B. The abnormal range includes a voltage range of a fifth threshold Th5 or more that is greater than a third normal voltage Vd3, where the third normal voltage Vd3 is the voltage of the second part B2 when the first switch 10A is normally in an off state and the second switch 10B is normally in an on state. According to this configuration, when the first switch 10A is normally in an off state and the second switch 10B is normally in an on state, the voltage of the second part B2 becomes the same value as the voltage of the low potential side of the power supply unit 90. By comparing the fifth threshold Th5 based on this value with the actual voltage value V of the second part B2, an open circuit failure of the second switch 10B can be detected.

[0072] <Embodiment 2>

[0073] Next, refer to Figure 4 、 Figure 5 The abnormality detection device 110 of Embodiment 2 will be described. Embodiment 2 is different from Embodiment 1 in that it has a third switch 10H and a third resistor unit 10J, and in the operation of the detection unit 10E, etc. The same reference numerals are assigned to the same structures as those in Embodiment 1, and the description of the same functions and effects as those in Embodiment 1 is omitted.

[0074] The third switch 10H uses a relay switch such as a semiconductor relay or a mechanical relay, for example. The third resistor unit 10J uses a resistor having two terminals. The resistance value of the third resistor unit 10J is R3. The third switch 10H is electrically connected in series with the third resistor unit 10J to form a series structure unit 10K. As Figure 4 shown, one end of the series structure unit 10K, that is, one end of the third switch 10H, is electrically connected to the third part B3. The other end of the series structure unit 10K, that is, the other end of the third resistor unit 10J, is electrically connected to the second part B2. The series structure unit 10K, the second resistor unit 10D, and the second switch 10B are electrically connected in parallel.

[0075] A first threshold Th11, a second threshold Th22, a third threshold Th33, a fourth threshold Th44, and a fifth threshold Th55 are stored in a ROM or the like of the detection unit 10E. The detection unit 10E has a function of comparing the voltage value V of the second part B2 with the first threshold Th11, the second threshold Th22, the third threshold Th33, the fourth threshold Th44, and the fifth threshold Th55 to determine whether the voltage of the second part B2 is in an abnormal state.

[0076] The first threshold Th11 and the second threshold Th22 are based on the first normal voltage Vd1, which is the voltage of the second part B2 when the first switch 10A, the second switch 10B, and the third switch 10H are normally in the off state. The first normal voltage Vd1 is a value obtained by dividing the output voltage Vo of the power supply unit 90 using the first resistor unit 10C (resistance value R1) and the second resistor unit 10D (resistance value R2), and is represented by Equation 1 in Embodiment 1.

[0077] The first threshold Th11 is smaller than the first normal voltage Vd1 by a specified value. The second threshold Th22 is larger than the first normal voltage Vd1 by a specified value. The values of the first threshold Th11 and the second threshold Th22 can be changed to desired magnitudes according to desired specifications.

[0078] The third threshold Th33 and the fourth threshold Th44 are based on the second normal voltage Vd2, which is the voltage of the second part B2 when the first switch 10A and the third switch 10H are normally in the on state and the second switch 10B is normally in the off state. Here, the second normal voltage Vd2 is a value obtained by dividing the voltage using the first resistor unit 10C (resistance value R1) and the trigger 91C (resistance value Ri) connected in parallel and the second resistor unit 10D (resistance value R2) and the third resistor unit 10J (resistance value R3) connected in parallel, and is represented by Equation 3 below.

[0079] [Mathematical formula 3]

[0080]

[0081] The third threshold Th33 is smaller than the second normal voltage Vd2 by a specified value. The fourth threshold Th44 is larger than the second normal voltage Vd2 by a specified value. The values of the third threshold Th33 and the fourth threshold Th44 can be changed to desired magnitudes according to desired specifications.

[0082] The fifth threshold Th55 is based on the third normal voltage Vd3, which is the voltage of the second part B2 when the first switch 10A and the third switch 10H are normally in the off state and the second switch 10B is normally in the on state. The third normal voltage Vd3 becomes the same voltage as the low-potential side terminal of the power supply unit 90 (ground potential). The fifth threshold Th55 is larger than the third normal voltage Vd3 by a specified value. The value of the fifth threshold Th55 can be changed to a desired magnitude according to desired specifications.

[0083] The first switching control of the detection unit 10E is a control that maintains the first switch 10A, the second switch 10B, and the third switch 10H in the off state. The second switching control of the detection unit 10E is a control that maintains the first switch 10A and the third switch 10H in the on state and maintains the second switch 10B in the off state. The third switching control of the detection unit 10E is a control that maintains the first switch 10A and the third switch 10H in the off state and maintains the second switch 10B in the on state.

[0084] 〔An example of the operation of the abnormality detection device〕

[0085] Next, an example of the operation of the abnormality detection device 110 will be described. In a vehicle equipped with the supply system 200, when the ignition switch is in the off state, the first switch 10A, the second switch 10B, and the third switch 10H are set to the off state. For example, in Figure 5 in step S11, if the ignition switch is switched from the off state to the on state ("Yes" in step S1), the process proceeds to step S12. In step S12, the detection unit 10E executes the first switching control that maintains the first switch 10A, the second switch 10B, and the third switch 10H in the off state.

[0086] The detection unit 10E obtains the voltage value V of the second part B2. In step S12, the detection unit 10E compares the voltage value V with the first threshold Th11 and the second threshold Th22 to determine whether the voltage of the second part B2 is within the abnormal range.

[0087] When the voltage value V is less than the first threshold Th11, it is presumed that the voltage of the second part B2 has dropped due to a disconnection of the first power line 92 between the first resistor part 10C and the power supply part 90 or a short-circuit fault of the second switch 10B. When the voltage value V is greater than the second threshold Th22, it is presumed that the voltage of the second part B2 has risen due to a disconnection of the second power line 93 between the second part B2 and the power supply part 90 or a short-circuit fault of the first switch 10A. Therefore, if the detection unit 10E determines that the voltage value V is less than the first threshold Th11 or the voltage value V is greater than the second threshold Th22 ("No" in step S12), the process proceeds to step S16. When the process proceeds to step S16, the detection unit 10E determines that the supply system 200 is in an abnormal state and ends Figure 5Processing in []. The abnormal range of the voltage of the second part B2 in step S12 includes at least any one of the voltage ranges below the first threshold Th11 smaller than the first normal voltage Vd1 and above the second threshold Th22 larger than the first normal voltage Vd1. The first normal voltage Vd1 is the voltage of the second part B2 when the first switch 10A, the second switch 10B, and the third switch 10H are normally in the off state. When the voltage value V is above the first threshold Th11 and below the second threshold Th22 (\"Yes\" in step S12), it transfers to step S13.

[0088] When it transfers to step S13, the detection unit 10E performs a second switching control to keep the first switch 10A and the third switch 10H in the on state and keep the second switch 10B in the off state. Then, it determines whether the voltage of the second part B2 is in the abnormal range. When it transfers to step S13, the detection unit 10E compares the voltage value V of the second part B2 with the third threshold Th33 and the fourth threshold Th44.

[0089] When the voltage value V is smaller than the third threshold Th33, it is presumed that the voltage of the second part B2 drops due to an open-circuit fault of the first switch 10A, an increase in the resistance value Ri caused by the deterioration of the initiator 91C, or an open circuit caused by a poor connection between the initiator 91C and the first power line 92. When the voltage value V is larger than the fourth threshold Th44, it is presumed that the voltage of the second part B2 rises due to a decrease in the resistance value Ri caused by the deterioration of the initiator 91C, or a short circuit of the initiator 91C caused by a poor connection between the initiator 91C and the first power line 92. Therefore, if the detection unit 10E determines that the voltage value V is smaller than the third threshold Th33 or the voltage value V is larger than the fourth threshold Th44 (\"No\" in step S13), it transfers to step S16. When it transfers to step S16, the detection unit 10E determines that the supply system 200 is in an abnormal state and ends Figure 5 Processing in []. The abnormal range of the voltage of the second part B2 in step S13 includes at least any one of the voltage ranges below the third threshold Th33 smaller than the second normal voltage Vd2 and above the fourth threshold Th44 larger than the second normal voltage Vd2. The second normal voltage Vd2 is the voltage of the second part B2 when the first switch 10A and the third switch 10H are normally in the on state and the second switch 10B is normally in the off state. When the voltage value V is above the third threshold Th33 and below the fourth threshold Th44 (\"Yes\" in step S13), it transfers to step S14.

[0090] When transferring to step S14, the detection unit 10E performs a third switching control to keep the first switch 10A and the third switch 10H in the off state and keep the second switch 10B in the on state. Then, it determines whether the voltage of the second part B2 is within the abnormal range. When transferring to step S14, the detection unit 10E compares the voltage value V of the second part B2 with the fifth threshold Th55.

[0091] When the voltage value V is greater than the fifth threshold Th55, it is presumed that the voltage of the second part B2 has risen due to an open-circuit fault of the second switch 10B. Therefore, if the detection unit 10E determines that the voltage value V is greater than the fifth threshold Th55 ( "No" in step S14), it transfers to step S16, and the detection unit 10E determines that the supply system 200 is in an abnormal state and ends Figure 5 the processing in. When the voltage value V is equal to or less than the fifth threshold Th55 ( "Yes" in step S14), it transfers to step S15. When transferring to step S15, the detection unit 10E determines that the supply system 200 is in a normal state and ends Figure 5 the processing in. The abnormal range of the voltage of the second part B2 in step S14 includes a voltage range above the fifth threshold that is greater than the third normal voltage Vd3. The third normal voltage Vd3 is the voltage of the second part B2 when the first switch 10A and the third switch 10H are normally in the off state and the second switch 10B is normally in the on state.

[0092] In addition, in the case of a structure in which the voltage value V is compared with each threshold by a comparator, the resistance values of the first resistor part 10C, the second resistor part 10D, the third resistor part 10J, and the trigger 91C can be set so that the value obtained by dividing the voltage on the high-potential side of the power supply part 90 by the first resistor part 10C and the second resistor part 10D is the same as the value obtained by dividing the voltage on the high-potential side of the power supply part 90 by the third resistor part 10J and the trigger 91C.

[0093] The abnormality detection device 110 includes a series structure part 10K formed by connecting the third switch 10H and the third resistor part 10J in series. One end of the series structure part 10K is electrically connected to the third part B3, and the other end of the series structure part 10K is electrically connected to the second part B2. According to this structure, by further adding the series structure part 10K formed by connecting the third switch 10H and the third resistor part 10J in series, it is possible to more finely judge the abnormality in the supply system 200.

[0094] In the abnormality detection device 110, when the detection unit 10E issues a disconnection instruction to the first switch 10A, the second switch 10B, and the third switch 10H, it determines whether the voltage of the second part B2 is within the abnormal range. The abnormal range includes at least either a voltage range of the first threshold Th11 or less that is smaller than the first normal voltage Vd1 and a voltage range of the second threshold Th22 or more that is larger than the first normal voltage Vd1. The first normal voltage Vd1 is the voltage of the second part B2 when the first switch 10A, the second switch 10B, and the third switch 10H are normally in the open state. According to this configuration, when the first switch 10A, the second switch 10B, and the third switch 10H are normally in the open state, the voltage of the second part B2 becomes the first normal voltage Vd1 obtained by dividing the output voltage Vo of the high potential side of the power supply unit 90 by the first resistor unit 10C and the second resistor unit 10D. By comparing the first threshold Th11 and the second threshold Th22 based on this value with the actual voltage value V of the second part B2, it is possible to detect a decrease or increase in the power supply voltage, a disconnection of the first power line 92 and the second power line 93, and a short circuit fault of the first switch 10A and the second switch 10B.

[0095] In the abnormality detection device 110, when the detection unit 10E issues a connection instruction to the first switch 10A and the third switch 10H and a disconnection instruction to the second switch 10B, it determines whether the voltage of the second part B2 is within the abnormal range. The abnormal range includes at least either a voltage range of the third threshold Th33 or less that is smaller than the second normal voltage Vd2 and a voltage range of the fourth threshold Th44 or more that is larger than the second normal voltage Vd2. The second normal voltage Vd2 is the voltage of the second part B2 when the first switch 10A and the third switch 10H are normally in the connected state and the second switch 10B is normally in the open state. According to this configuration, when the first switch 10A and the third switch 10H are normally in the connected state, the second switch 10B is normally in the open state, and the resistance value Ri of the initiator 91C of the pyrotechnic circuit breaker 91 is normal, the voltage of the second part B2 becomes a value obtained by dividing the output voltage Vo of the high potential side of the power supply unit 90 by a combined resistor formed by connecting the initiator 91C and the first resistor unit 10C in parallel and a combined resistor formed by connecting the second resistor unit 10D and the third resistor unit 10J in parallel. By comparing the third threshold Th33 and the fourth threshold Th44 based on this value with the actual voltage value V of the second part B2, it is possible to detect an open circuit fault of the first switch 10A, a poor connection of the pyrotechnic circuit breaker 91, and a change in the resistance value Ri of the initiator 91C of the pyrotechnic circuit breaker 91.

[0096] In the abnormality detection device 110, when the detection unit 10E issues a disconnection instruction to the first switch 10A and the third switch 10H and issues a connection instruction to the second switch 10B, it determines whether the voltage of the second part B2 is within an abnormal range. The abnormal range includes a voltage range of the fifth threshold Th55 or more that is larger than the third normal voltage Vd3, and the third normal voltage Vd3 is the voltage of the second part B2 when the first switch 10A and the third switch 10H are normally in the disconnected state and the second switch 10B is normally in the connected state. According to this configuration, when the first switch 10A and the third switch 10H are normally in the disconnected state and the second switch 10B is normally in the connected state, the voltage of the second part B2 becomes the same value as the voltage of the low potential side of the power supply unit 90. By comparing the fifth threshold Th55 based on this value with the actual voltage value V of the second part B2, an open circuit failure of the second switch 10B can be detected.

[0097] In the abnormality detection device 110, the value obtained by dividing the output voltage Vo of the high potential side of the power supply unit 90 by the first resistor unit 10C and the second resistor unit 10D is the same as the value obtained by dividing the output voltage Vo of the high potential side of the power supply unit 90 by the third resistor unit 10J and the initiator 91C of the squib circuit breaker 91. According to this configuration, it is possible to make the first normal voltage Vd1 that is the reference for the first threshold Th11 and the second threshold Th22 the same as the second normal voltage Vd2 that is the reference for the third threshold Th33 and the fourth threshold Th44. Therefore, when the detection unit 10E is constituted by a comparator, the number of comparators provided can be suppressed.

[0098] <Other embodiments>

[0099] It should be considered that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed this time, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0100] Different from Embodiments 1 and 2, the first switching control, the second switching control, and the third switching control may also be executed in a changed order.

[0101] This abnormality detection device may also be applied to a system that supplies current to the inflator of an airbag.

[0102] Different from Embodiment 2, one end of the third switch, which is one end of the series structure part, may be electrically connected to the second part, and the other end of the third resistor part, which is the other end of the series structure part, may be electrically connected to the third part.

[0103] The first resistor section, the second resistor section, and the third resistor section only need to have resistance elements, and in addition to the resistance elements, they can also be composed of multiple components such as inductors and capacitors.

[0104] Reference Numeral Explanation 10, 110... Abnormality detection device 10A... First switch 10B... Second switch 10C... First resistor section 10D... Second resistor section 10E... Detection section 10H... Third switch 10J... Third resistor section 10K... Series structure section 90... Power supply section 91... Pyrotechnic circuit breaker 91C... Initiator 91D... Displacement section 91E... Conductor section 91F... Gunpowder 92... First power line 93... Second power line 100, 200... Supply system B1... First part B2... Second part B3... Third part R1... Resistance value of the first resistor section R2... Resistance value of the second resistor section R3... Resistance value of the third resistor section Ri... Resistance value of the initiator Th1, Th11... First threshold Th2, Th22... Second threshold Th3, Th33... Third threshold Th4, Th44... Fourth threshold Th5, Th55... Fifth threshold V... Voltage value of the second part Vd1... First normal voltage Vd2... Second normal voltage Vd3... Third normal voltage Vo... Output voltage of the power supply section W... Conductive path W1... First conductive path W2... Second conductive path.

Claims

1. An abnormality detection device used in a supply system, The supply system includes: a power supply unit that supplies power; a first power line provided between the high-potential side terminal of the power supply unit and the power supply object; and a second power line provided between the low-potential side terminal of the power supply unit and the power supply object. The abnormality detection device includes: A first switch provided in the first power line; A second switch provided in the second power line; A first resistor portion and a second resistor portion that form a conduction path; and A detection unit that detects the voltage state. When the first switch is in the on state, power conduction through the first switch is allowed, and when the first switch is in the off state, power conduction through the first switch is cut off. When the second switch is in the on state, power conduction through the second switch is allowed, and when the second switch is in the off state, power conduction through the second switch is cut off. One end of the first resistor portion is electrically connected to a first portion between the power supply unit and the first switch in the first power line, and the other end of the first resistor portion is electrically connected to a second portion between the second switch and the power supply object in the second power line. One end of the second resistor portion is electrically connected to the second portion, and the other end of the second resistor portion is electrically connected to a third portion between the second switch and the power supply unit in the second power line. The detection unit detects the voltage state of the second portion when at least one of the first switch and the second switch is controlled to be in the off state.

2. The abnormality detection device according to claim 1, wherein The power supply object has a pyrotechnic circuit breaker, and the pyrotechnic circuit breaker is provided in a specified conductive path. The pyrotechnic circuit breaker has a conductor portion that shorts a first conductive path and a second conductive path of the conductive path, and the pyrotechnic circuit breaker explodes and cuts off the conductor portion when a specified current flows between the first power line and the second power line.

3. The abnormality detection device according to claim 1 or claim 2, wherein The detection unit determines whether the voltage of the second portion is within an abnormal range when a disconnection instruction is issued to the first switch and the second switch. The abnormal range includes at least one of a voltage range equal to or lower than a first threshold smaller than a first normal voltage and a voltage range equal to or higher than a second threshold larger than the first normal voltage. The first normal voltage is the voltage of the second portion when the first switch and the second switch are normally in the off state.

4. The abnormality detection device according to claim 1 or claim 2, wherein The detection unit determines whether the voltage of the second portion is within an abnormal range when a connection instruction is issued to the first switch and a disconnection instruction is issued to the second switch. The abnormal range includes at least any one of a voltage range below a third threshold smaller than the second normal voltage and a voltage range above a fourth threshold larger than the second normal voltage. The second normal voltage is the voltage of the second part when the first switch is normally in the on state and the second switch is normally in the off state.

5. The abnormality detection device according to claim 1 or claim 2, wherein, the detection unit determines whether the voltage of the second part is within the abnormal range when a disconnection instruction is issued to the first switch and a connection instruction is issued to the second switch; the abnormal range includes a voltage range above a fifth threshold larger than the third normal voltage. The third normal voltage is the voltage of the second part when the first switch is normally in the off state and the second switch is normally in the on state.

6. The abnormality detection device according to claim 1 or claim 2, wherein, the abnormality detection device includes a series structure part formed by connecting a third switch and a third resistor part in series, one end of the series structure part is electrically connected to the third part, and the other end of the series structure part is electrically connected to the second part.

7. The abnormality detection device according to claim 6, wherein, the detection unit determines whether the voltage of the second part is within the abnormal range when disconnection instructions are issued to the first switch, the second switch, and the third switch; the abnormal range includes at least any one of a voltage range below a first threshold smaller than the first normal voltage and a voltage range above a second threshold larger than the first normal voltage. The first normal voltage is the voltage of the second part when the first switch, the second switch, and the third switch are normally in the off state.

8. The abnormality detection device according to claim 6, wherein, the detection unit determines whether the voltage of the second part is within the abnormal range when connection instructions are issued to the first switch and the third switch and a disconnection instruction is issued to the second switch; the abnormal range includes at least any one of a voltage range below a third threshold smaller than the second normal voltage and a voltage range above a fourth threshold larger than the second normal voltage. The second normal voltage is the voltage of the second part when the first switch and the third switch are normally in the on state and the second switch is normally in the off state.

9. The abnormality detection device according to claim 6, wherein, the detection unit determines whether the voltage of the second part is within the abnormal range when disconnection instructions are issued to the first switch and the third switch and a connection instruction is issued to the second switch; the abnormal range includes a voltage range above a fifth threshold larger than the third normal voltage. The third normal voltage is the voltage of the second part when the first switch and the third switch are normally in the off state and the second switch is normally in the on state.

10. The abnormality detection device according to claim 6, Among them, the value obtained by dividing the voltage on the high-potential side of the power supply unit using the first resistor unit and the second resistor unit is the same as the value obtained by dividing the voltage on the high-potential side of the power supply unit using the third resistor unit and the power supply target.

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