Current cutoff device

Abstract

A current cutoff device (30) comprises a first cutoff unit (41), a second cutoff unit (42), and a control unit (50). The control unit (50) switches the first cutoff unit (41) to a first cutoff state when the current flowing through a first conductive path (31) in a series connection state exceeds a series threshold value, switches the first cutoff unit (41) to the first cutoff state when the current flowing through the first conductive path (31) in a parallel connection state exceeds a first parallel threshold value, and switches the second cutoff unit (42) to a second cutoff state when the current flowing through a second conductive path (32) in the parallel connection state exceeds a second parallel threshold value. The first parallel threshold value and the second parallel threshold value are lower than the series threshold value.

Description

Current interruption device

[0001] The present disclosure relates to a current interruption device.

[0002] Patent Document 1 discloses a vehicle power interruption system. This vehicle power interruption system includes a cutoff control unit and an explosive cutoff unit. When an overcurrent occurs in the conductor part of the explosive cutoff unit, for example, the cutoff control unit switches by physically destroying the explosive cutoff unit from the connected state to the cutoff state.

[0003] Patent Document 2 discloses a power supply system in which a first high-voltage battery and a second high-voltage battery can be switched between series connection and parallel connection.

[0004] Japanese Unexamined Patent Application Publication No. 2022-13791, Japanese Unexamined Patent Application Publication No. 2022-128691

[0005] In the power supply system of Patent Document 2, there is a conductive path through which current flows in series connection and only the output current of one battery flows in parallel connection. When interrupting the current using a cutoff unit such as the explosive cutoff unit of Patent Document 1 in this conductive path, if the overcurrent threshold is set assuming the overcurrent in series connection, there is a possibility that it cannot be interrupted in parallel connection. Conversely, if the overcurrent threshold is set assuming the overcurrent in parallel connection, there is a possibility that it will be interrupted even though there is no overcurrent in series connection.

[0006] An object of the present disclosure is to provide a technique that can appropriately interrupt current easily in any state of series connection and parallel connection.

[0007] The current interruption device of the present disclosure is included in an in-vehicle system comprising: a battery including a first battery and a second battery that can switch between series connection and parallel connection; a first conductive path through which current flows when the batteries are connected in series and through which only the current flowing through the first battery flows when the batteries are connected in parallel; and a second conductive path through which current flows when the batteries are connected in series and through which only the current flowing through the second battery flows when the batteries are connected in parallel, the current interruption device comprising: a first interruption unit that switches from a first permissible state that allows current to flow through the first conductive path to a first interruption state that interrupts the current flowing through the first conductive path; a second interruption unit that switches from a second permissible state that allows current to flow through the second conductive path to a second interruption state that interrupts the current flowing through the second conductive path; and a control unit that controls the first interruption unit and the second interruption unit. The control unit switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the series threshold in the series connection state, switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the first parallel threshold in the parallel connection state, and switches the second interruption unit to the second interruption state when the current flowing through the second conductive path exceeds the second parallel threshold in the parallel connection state, wherein the first parallel threshold and the second parallel threshold are smaller than the series threshold.

[0008] According to the technology disclosed herein, it is possible to appropriately interrupt the current in both series and parallel connection states.

[0009] Figure 1 is a schematic diagram showing an in-vehicle system including a current interruption device of the first embodiment. Figure 2 is a schematic diagram showing an in-vehicle system of the first embodiment when connected in series. Figure 3 is a schematic diagram showing an in-vehicle system of the first embodiment when connected in parallel. Figure 4 is a conceptual explanatory diagram showing a short circuit in the in-vehicle system of the first embodiment when connected in series. Figure 5 is a conceptual explanatory diagram showing a short circuit in the first conductive path when the in-vehicle system of the first embodiment is connected in parallel. Figure 6 is a conceptual explanatory diagram showing a short circuit in the second conductive path when the in-vehicle system of the first embodiment is connected in parallel. Figure 7 is a flowchart showing the processing performed by the first control circuit of the first embodiment. Figure 8 is a flowchart showing the processing performed by the second control circuit of the first embodiment. Figure 9 is a schematic diagram showing an in-vehicle system including a current interruption device of the second embodiment.

[0010] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described.

[0011] [1] A current interruption device included in an in-vehicle system comprising: a battery including a first battery and a second battery that can switch between series connection and parallel connection; a first conductive path through which current flows when the battery is in series and when it is in parallel and through which the current flows through the first battery and through which the current flows through the second battery flows; a second conductive path through which current flows when the battery is in series and through which the current flows through the second battery and through which the current flows through the second battery flows when it is in parallel; a current interruption device included in an in-vehicle system comprising: a first interruption unit that switches from a first permissible state that allows current to flow through the first conductive path to a first interruption state that interrupts the current flowing through the first conductive path; a second interruption unit that switches from a second permissible state that allows current to flow through the second conductive path to a second interruption state that interrupts the current flowing through the second conductive path; and a control unit that controls the first interruption unit and the second interruption unit. The control unit switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the series threshold in the series connection state, switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the first parallel threshold in the parallel connection state, and switches the second interruption unit to the second interruption state when the current flowing through the second conductive path exceeds the second parallel threshold in the parallel connection state, wherein the first parallel threshold and the second parallel threshold are smaller than the series threshold in the current interruption device.

[0012] The control unit of the current interruption device described above can interrupt the current flowing through the first conductive path when the current flowing through the first conductive path exceeds the series threshold when the devices are connected in series. Furthermore, when the devices are connected in parallel, the control unit can detect overcurrent in the first conductive path using a smaller threshold than when the devices are connected in series, and interrupt the current flowing through the first conductive path. Furthermore, when the devices are connected in parallel, the control unit can detect overcurrent in the second conductive path using a smaller threshold than when the devices are connected in series, and interrupt the current flowing through the second conductive path. In other words, the current interruption device is designed to effectively interrupt current in both series and parallel connections.

[0013] [2] The current interruption device described in [1], wherein the first parallel threshold and the second parallel threshold are the same value.

[0014] The above-described current interruption device is designed to appropriately interrupt the current flowing through the first conductive path and the current flowing through the second conductive path when the output voltages of the first and second batteries are the same and they are connected in parallel.

[0015] [3] The current interruption device according to [1] or [2], wherein the control unit switches the second interruption unit to the second interruption state when the current flowing through the second conductive path exceeds the series threshold in the series connection state.

[0016] In the series connection state, the control unit switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the series threshold, and switches the second interruption unit to the second interruption state when the current flowing through the second conductive path exceeds the series threshold. Therefore, the current interruption device can more reliably interrupt overcurrents when a current exceeding the series threshold occurs in the series connection state.

[0017] [4] The control unit determines whether the battery is connected in series or in parallel based on the battery voltage. Current interruption device according to any one of [1] to [3].

[0018] With this configuration, the current interruption device can determine on its own whether the connections are in series or parallel.

[0019] [5] The control unit determines whether the connection is in series or parallel based on the current in the conductive path which switches between a state in which current flows and a state in which no current flows in the series connection and the parallel connection. The current interruption device according to any one of [1] to [3].

[0020] With this configuration, the current interruption device can determine on its own whether the connections are in series or parallel.

[0021] [6] The current interruption device according to any one of [1] to [5], wherein the battery is housed in a battery pack case, and the first interruption unit, the second interruption unit, and the control unit are housed in the case.

[0022] With this configuration, the first interruption unit, the second interruption unit, and the control unit can be housed together in the case that contains the battery.

[0023] [7] The control unit comprises a first control circuit and a second control circuit separate from the first control circuit, wherein the first control circuit controls the first interruption unit and the second control circuit controls the second interruption unit, the current interruption device according to any one of [1] to [6].

[0024] With this configuration, the first and second interruption units can be controlled by separate control circuits.

[0025] [Details of Embodiments of the Disclosure] 1. First Embodiment 1-1. Configuration of the In-Vehicle System 1 The in-vehicle system 1 shown in Figure 1 comprises a battery 10, a power line 11, and a load 12. The power line 11 is provided between the battery 10 and the load 12. Power is supplied from the battery 10 to the load 12 via the power line 11. The power line 11 has a positive electrode side power line 11A and a negative electrode side power line 11B.

[0026] The battery 10 includes a first battery 13 and a second battery 14. The first battery 13 and the second battery 14 are composed of, for example, lithium-ion batteries and sodium-ion batteries. In this embodiment, the output voltage of the first battery 13 when fully charged and the output voltage of the second battery 14 when fully charged are the same, for example, 400V.

[0027] The first battery 13 and the second battery 14 switch between series connection and parallel connection between the positive electrode power path 11A and the negative electrode power path 11B. When connected in series, the output voltage of battery 10 is, for example, 800V. When connected in parallel, the output voltage of battery 10 is, for example, 400V.

[0028] In series connection, the positive terminal 13A of the first battery 13 is electrically connected to the positive power line 11A, the negative terminal 13B of the first battery 13 is electrically connected to the positive terminal 14A of the second battery 14, and the negative terminal 14B of the second battery 14 is electrically connected to the negative power line 11B. In parallel connection, the positive terminal 13A of the first battery 13 and the positive terminal 14A of the second battery 14 are electrically connected to the positive power line 11A, and the negative terminal 13B of the first battery 13 and the negative terminal 14B of the second battery 14 are electrically connected to the negative power line 11B.

[0029] The in-vehicle system 1 includes a switching unit 20. The switching unit 20 switches between a series connection and a parallel connection of the first battery 13 and the second battery 14. The switching unit 20 switches between a first state in which the first battery 13 and the second battery 14 are connected in series, and a second state in which the first battery 13 and the second battery 14 are connected in parallel.

[0030] The switching unit 20 includes a first switch unit 21, a second switch unit 22, and a third switch unit 23. The first switch unit 21, the second switch unit 22, and the third switch unit 23 are also referred to as switch units 21, 22, and 23. The switch units 21, 22, and 23 may be composed of semiconductor switching elements such as MOSFETs, or they may be composed of mechanical switches having contacts. The switch units 21, 22, and 23 are connected in series between the positive-side power path 11A and the negative-side power path 11B. The switch units 21, 22, and 23 are arranged in order from the positive-side power path 11A to the negative-side power path 11B.

[0031] The second switch unit 22 is provided between the negative terminal 13B of the first battery 13 and the positive terminal 14A of the second battery 14. The first switch unit 21 is provided between the conductive path between the second switch unit 22 and the positive terminal 14A of the second battery 14 and the positive power path 11A. The third switch unit 23 is provided between the conductive path between the first switch unit 21 and the negative terminal 13B of the first battery 13 and the negative power path 11B.

[0032] As shown in Figure 2, the switching unit 20 enters a first state when the second switch unit 22 is ON and the first switch unit 21 and the third switch unit 23 are OFF. As a result, current flows as shown by the arrows in Figure 2. As shown in Figure 3, the switching unit 20 enters a second state when the second switch unit 22 is OFF and the first switch unit 21 and the third switch unit 23 are ON. As a result, current flows as shown by the arrows in Figure 3.

[0033] The in-vehicle system 1 includes a switching control unit 24 that controls the switching unit 20. The switching control unit 24 is configured, for example, by a microcomputer. The switching control unit 24 switches the switching unit 20 between a first state and a second state.

[0034] The in-vehicle system 1 includes a battery pack case 25. The case 25 houses the battery 10, the switching unit 20, and the switching control unit 24.

[0035] The in-vehicle system 1 includes a first conductive path 31 and a second conductive path 32. The first conductive path 31 is a conductive path through which current flows when connected in series, through which current flows through the first battery 13 and the second battery 14, and when connected in parallel, through which only the current flowing through the first battery 13 flows. Specifically, the first conductive path 31 is a conductive path through which the first battery 13 is provided, and is a conductive path between a first connection point P1 between one end of the first switch unit 21 and the positive electrode side power path 11A, and a third connection point P3 between the other end of the second switch unit 22 and one end of the third switch unit 23.

[0036] The second conductive path 32 is a conductive path through which current flows when the batteries are connected in series, and through which only the current flowing through the second battery 14 flows when the batteries are connected in parallel. Specifically, the second conductive path 32 is a conductive path through which the second battery 14 is provided, and is a conductive path between the second connection point P2 between the other end of the first switch unit 21 and one end of the second switch unit 22, and the fourth connection point P4 between the other end of the third switch unit 23 and the negative electrode power path 11B.

[0037] Incidentally, when a short circuit occurs in the in-vehicle system 1, the magnitude of the overcurrent flowing through the first conductive path 31 and the second conductive path 32 may differ depending on whether the connections are in series or parallel. For example, as shown in Figure 4, if the positive-side power path 11A is short-circuited to the negative-side power path 11B in a series connection, the current loops along the path indicated by the arrow in Figure 4, resulting in an overcurrent. Also, as shown in Figure 5, if one end of the first conductive path 31 is short-circuited to the other end in a parallel connection, the current loops along the path indicated by the arrow in Figure 5, resulting in an overcurrent. Furthermore, as shown in Figure 6, if one end of the second conductive path 32 is short-circuited to the other end in a parallel connection, the current loops along the path indicated by the arrow in Figure 6, resulting in an overcurrent. In the case of Figure 5, the magnitude of the overcurrent flowing through the first conductive path 31 is smaller compared to the case of Figure 4. In the case of Figure 6, the magnitude of the overcurrent flowing through the second conductive path 32 is smaller compared to the case of Figure 4. Therefore, in order to appropriately interrupt the current in any state, the in-vehicle system 1 includes a current interruption device 30.

[0038] 1-2. Configuration of the current interruption device 30 The current interruption device 30 is housed in a case 25. The current interruption device 30 comprises a first interruption unit 41, a second interruption unit 42, a first current detection unit 43, a second current detection unit 44, a voltage detection unit 45, and a control unit 50. The first conductive path 31, the second conductive path 32, the first interruption unit 41, the second interruption unit 42, the first current detection unit 43, the second current detection unit 44, the voltage detection unit 45, and the control unit 50 are housed in a case 25.

[0039] The first interruption unit 41 is provided in the first conductive path 31. The first interruption unit 41 switches from a first allowable state, which allows current to flow through the first conductive path 31, to a first interruption state, which interrupts the current flowing through the first conductive path 31. The second interruption unit 42 is provided in the second conductive path 32. The second interruption unit 42 switches from a second allowable state, which allows current to flow through the second conductive path 32, to a second interruption state, which interrupts the current flowing through the second conductive path 32. The first interruption unit 41 and the second interruption unit 42 may be configured by, for example, a pyro fuse or other pyrotechnic circuit breaker, a semiconductor switching element, or a mechanical switch with contacts.

[0040] The first current detection unit 43 detects the current flowing through the first conductive path 31. The first current detection unit 43 is configured, for example, by a known current sensor. The signal indicating the detection result from the first current detection unit 43 is input to the control unit 50. The second current detection unit 44 detects the current flowing through the second conductive path 32. The second current detection unit 44 is configured, for example, by a known current sensor. The signal indicating the detection result from the second current detection unit 44 is input to the control unit 50. The voltage detection unit 45 detects the voltage across the battery 10. The voltage detection unit 45 is configured, for example, by a known voltage detection circuit. The signal indicating the detection result from the voltage detection unit 45 is input to the control unit 50.

[0041] The control unit 50 is provided separately from the switching control unit 24. The control unit 50 controls the first interruption unit 41 and the second interruption unit 42. When the current flowing through the first conductive path 31 exceeds the series threshold in a series connection state, the control unit 50 switches the first interruption unit 41 to the first interruption state. When the current flowing through the first conductive path 31 exceeds the first parallel threshold in a parallel connection state, the control unit 50 switches the second interruption unit 42 to the second interruption state when the current flowing through the second conductive path 32 exceeds the series threshold in a series connection state. When the current flowing through the second conductive path 32 exceeds the second parallel threshold in a parallel connection state, the control unit 50 switches the second interruption unit 42 to the second interruption state. The first parallel threshold and the second parallel threshold are smaller than the series threshold. In this embodiment, the first parallel threshold and the second parallel threshold are the same, but they do not have to be the same. The serial threshold, the first parallel threshold, and the second parallel threshold may be fixed values ​​or variable values.

[0042] The control unit 50 determines whether the batteries 10 are connected in series or in parallel based on their voltage. For example, the control unit 50 determines that the batteries are connected in series if the voltage of the batteries 10 exceeds a threshold voltage, and determines that they are connected in parallel if the voltage of the batteries 10 is below the threshold voltage. The threshold voltage is, for example, 600V.

[0043] The control unit 50 includes a first control circuit 51 and a second control circuit 52. The first control circuit 51 controls the first interruption unit 41. The second control circuit 52 is provided separately from the first control circuit 51 and controls the second interruption unit 42. The control by the first control circuit 51 and the control by the second control circuit 52 may be implemented by hardware or by software.

[0044] A signal indicating the detection result by the voltage detection unit 45 is input to the first control circuit 51. The first control circuit 51 determines whether it is a series connection or a parallel connection based on the voltage of the battery 10. When the first control circuit 51 determines that it is a series connection, it determines whether the current flowing through the first conduction path 31 exceeds the series threshold value. When the first control circuit 51 determines that the current flowing through the first conduction path 31 exceeds the series threshold value, it switches the first cutoff unit 41 to the first cutoff state. When the first control circuit 51 determines that it is a parallel connection, it determines whether the current flowing through the first conduction path 31 exceeds the first parallel threshold value. When the first control circuit 51 determines that the current flowing through the first conduction path 31 exceeds the first parallel threshold value, it switches the first cutoff unit 41 to the first cutoff state.

[0045] The first control circuit 51 performs the process shown in FIG. 7, for example. In step S11, the first control circuit 51 determines whether the voltage of the battery 10 before a predetermined time exceeds the threshold voltage. The reason for setting it as "before a predetermined time" is to refer to the voltage of the battery 10 before being affected by a short circuit when a short circuit occurs. The predetermined time is, for example, 10 seconds. When the first control circuit 51 determines that the voltage of the battery 10 before a predetermined time exceeds the threshold voltage (Yes in step S11), in step S12, it sets the series threshold value as the overcurrent threshold value. When the first control circuit 51 determines that the voltage of the battery 10 before a predetermined time does not exceed the threshold voltage (No in step S11), in step S13, it sets the first parallel threshold value as the overcurrent threshold value. After step S12 or after step S13, the first control circuit 51 determines whether the current flowing through the first conduction path 31 exceeds the overcurrent threshold value. When the first control circuit 51 determines that the current flowing through the first conduction path 31 does not exceed the overcurrent threshold value (No in step S14), it returns to step S11. When the first control circuit 51 determines that the current flowing through the first conduction path 31 exceeds the overcurrent threshold value (Yes in step S14), in step S15, it switches the first cutoff unit 41 to the first cutoff state.

[0046] The second control circuit 52 receives a signal indicating the detection result from the voltage detection unit 45. The second control circuit 52 determines whether the battery 10 is connected in series or in parallel based on the voltage of the battery 10. If the second control circuit 52 determines that it is connected in series, it determines whether the current flowing through the second conductive path 32 exceeds the series threshold. If the second control circuit 52 determines that the current flowing through the second conductive path 32 exceeds the series threshold, it switches the second interruption unit 42 to the second interruption state. If the second control circuit 52 determines that it is connected in parallel, it determines whether the current flowing through the second conductive path 32 exceeds the second parallel threshold. If the second control circuit 52 determines that the current flowing through the second conductive path 32 exceeds the second parallel threshold, it switches the second interruption unit 42 to the second interruption state.

[0047] The second control circuit 52 performs the processing shown in Figure 8, for example. In step S21, the second control circuit 52 determines whether the voltage of the battery 10 a predetermined time ago exceeds the threshold voltage. If the second control circuit 52 determines that the voltage of the battery 10 a predetermined time ago exceeds the threshold voltage (if Yes in step S21), in step S22, it sets the series threshold as the overcurrent threshold. If the second control circuit 52 determines that the voltage of the battery 10 a predetermined time ago does not exceed the threshold voltage (if No in step S21), in step S23, it sets the second parallel threshold as the overcurrent threshold. After step S22 or after step S23, the second control circuit 52 determines whether the current flowing through the second conductive path 32 exceeds the overcurrent threshold. If the second control circuit 52 determines that the current flowing through the second conductive path 32 does not exceed the overcurrent threshold (if No in step S24), it returns to step S21. If the second control circuit 52 determines that the current flowing through the second conductive path 32 exceeds the overcurrent threshold (if the answer is Yes in step S24), it switches the second interruption unit 42 to the second interruption state in step S25.

[0048] 1-3. In the case of a series connection, the control unit 50 of the current interruption device 30 of the first embodiment can interrupt the current flowing through the first conduction path 31 when the current flowing through the first conduction path 31 exceeds the series use threshold value. Also, in the case of a parallel connection, the control unit 50 can detect an overcurrent in the first conduction path 31 using a smaller threshold value compared to the case of a series connection, and interrupt the current flowing through the first conduction path 31. Further, in the case of a parallel connection, the control unit 50 can detect an overcurrent in the second conduction path 32 using a smaller threshold value compared to the case of a series connection, and interrupt the current flowing through the second conduction path 32. That is, the current interruption device 30 can appropriately interrupt the current easily in either the series connection state or the parallel connection state.

[0049] The output voltages of the first battery 13 and the second battery 14 are the same, and the first parallel use threshold value and the second parallel use threshold value are the same value. For this reason, the current interruption device 30 can appropriately interrupt the current flowing through the first conduction path 31 and the current flowing through the second conduction path 32 easily when in a parallel connection.

[0050] In the case of a series connection, when the current flowing through the first conduction path 31 exceeds the series use threshold value, the control unit 50 switches the first interruption unit 41 to the first interruption state, and when the current flowing through the second conduction path 32 exceeds the series use threshold value, switches the second interruption unit 42 to the second interruption state. For this reason, when an overcurrent exceeding the series use threshold value occurs in the series connection state, the current interruption device 30 can more reliably interrupt the overcurrent.

[0051] The control unit 50 determines whether it is a series connection or a parallel connection based on the voltage of the battery 10. For this reason, the current interruption device 30 can determine by itself whether it is a series connection or a parallel connection without acquiring information of the switching unit 20 from the switching control unit 24.

[0052] The first interruption unit 41, the second interruption unit 42, and the control unit 50 are collectively accommodated in the case 25 that houses the battery 10.

[0053] The current interruption device 30 can control the first interruption unit 41 and the second interruption unit 42 by separate control circuits.

[0054] 2. Second Embodiment In the second embodiment, an example of determining whether a connection is in series or parallel using a method different from that of the first embodiment will be described. In the second embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed explanations are omitted.

[0055] As shown in Figure 9, the in-vehicle system 201 of the second embodiment includes a current interruption device 230 instead of the current interruption device 30 of the first embodiment. The current interruption device 230 includes a third current detection unit 245 instead of the voltage detection unit 45 of the first embodiment.

[0056] The in-vehicle system 201 includes a conductive path 33 that switches between a state where current flows and a state where no current flows depending on whether the connections are in series or parallel. The conductive path 33 is a conductive path on which a second switch unit 22 is provided, and is provided between a second connection unit P2 and a third connection unit P3. Current flows through the conductive path 33 when it is in series connection, and no current flows when it is in parallel connection. The third current detection unit 245 detects the current flowing through the conductive path 33. The third current detection unit 245 is configured, for example, by a known current sensor. The signal indicating the detection result of the third current detection unit 245 is input to the control unit 50. The control unit 50 determines whether the connections are in series or parallel based on the current flowing through the conductive path 33. Specifically, the control unit 50 determines that it is in series connection if the current flowing through the conductive path 33 exceeds a threshold current, and determines that it is in parallel connection if the current flowing through the conductive path 33 is less than or equal to the threshold current.

[0057] The control unit 50 performs the processing shown in Figures 7 and 8 described in the first embodiment. However, in step S11 in Figure 7 and step S21 in Figure 8, the control unit 50 performs the processing of determining whether the current flowing through the conductive path 33 exceeds the threshold current, instead of determining whether the voltage of the battery 10 a predetermined time ago exceeds the threshold voltage.

[0058] As described above, the current interruption device 230 of the second embodiment can also determine whether the connections are in series or parallel without obtaining information from the switching control unit 24.

[0059] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of the features of the embodiments described above or below is possible as long as it does not contradict the original. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. In addition, the embodiments described above may be modified as follows.

[0060] In the embodiments described above, the threshold for the first parallel processing and the threshold for the second parallel processing were the same value, but the threshold for the first parallel processing and the threshold for the second parallel processing may be different values.

[0061] In each of the above embodiments, the control unit 50 is configured to switch the first interruption unit 41 to the first interruption state when the current flowing through the first conductive path 31 exceeds the series threshold when connected in series, and to switch the second interruption unit 42 to the second interruption state when the current flowing through the second conductive path 32 exceeds the series threshold when connected in series. In contrast, the control unit 50 may be configured to switch the first interruption unit 41 to the first interruption state when the current flowing through the first conductive path 31 exceeds the series threshold when connected in series, while not switching the second interruption unit 42 to the second interruption state even if the current flowing through the second conductive path 32 exceeds the series threshold.

[0062] The arrangement of the first battery 13 and the second battery 14 may be reversed. In the above embodiments, the first battery 13 was positioned on the positive electrode side of the power path 11A than the second battery 14, but the first battery 13 may also be positioned on the negative electrode side of the power path 11B than the second battery 14.

[0063] In the embodiments described above, the switching control unit 24 was provided separately from the control unit 50, but the switching control unit 24 may also be included in the control unit 50. In this case, the control unit 50 does not need to determine whether the connections are in series or parallel based on the voltage of the battery 10 or the current flowing through the conductive path 33.

[0064] In the above embodiments, the control entity that controls the first interruption unit 41 and the control entity that controls the second interruption unit 42 were separate entities, but they may be a single entity.

[0065] In the second embodiment described above, the "conductive path that switches between a state where current flows and a state where no current flows depending on whether it is connected in series or in parallel" was a "conductive path where current flows when connected in series and no current flows when connected in parallel," but it may also be a "conductive path where no current flows when connected in series and current flows when connected in parallel."

[0066] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0067] 1...In-vehicle system 10...Battery 11...Power path 11A...Positive power path 11B...Negative power path 12...Load 13...First battery 13A...Positive terminal of the first battery 13B...Negative terminal of the first battery 14...Second battery 14A...Positive terminal of the second battery 14B...Positive terminal of the second battery 20...Switching unit 21...First switch unit 22...Second switch unit 23...Third switch unit 24...Switching control unit 25...Case 30...Current interruption device 31...First conductive path 32...Second conductive path 33...Conductive path that switches between a current-flowing state and a current-non-flowing state depending on whether it is connected in series or parallel 41...First interruption unit 42...Second interruption unit 43...First current detection unit 44...Second current detection unit 45...Voltage detection unit 50...Control unit 51...First control circuit 52...Second control circuit 201...In-vehicle system 230...Current interruption device 245...Third current detection unit P1...First connection unit P2...Second connection unit P3...Third connection unit P4...Fourth connection unit

Claims

1. A current interruption device included in an in-vehicle system comprising: a battery including a first battery and a second battery that can switch between series and parallel connections; a first conductive path through which current flows when the battery is in series and through which only the current flowing through the first battery flows when the battery is in parallel; and a second conductive path through which current flows when the battery is in series and through which only the current flowing through the second battery flows when the battery is in parallel, the current interruption device comprising: a first interruption unit that switches from a first permissible state that allows current to flow through the first conductive path to a first interruption state that interrupts the current flowing through the first conductive path; a second interruption unit that switches from a second permissible state that allows current to flow through the second conductive path to a second interruption state that interrupts the current flowing through the second conductive path; and a control unit that controls the first interruption unit and the second interruption unit. The control unit switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the series threshold in the series connection state, switches the first interruption unit to the first interruption state when the current flowing through the first conductive path exceeds the first parallel threshold in the parallel connection state, and switches the second interruption unit to the second interruption state when the current flowing through the second conductive path exceeds the second parallel threshold in the parallel connection state, wherein the first parallel threshold and the second parallel threshold are smaller than the series threshold in the current interruption device.

2. The current interruption device according to claim 1, wherein the first parallel threshold and the second parallel threshold are the same value.

3. The current interruption device according to claim 1 or 2, wherein the control unit switches the second interruption unit to the second interruption state when the current flowing through the second conductive path exceeds the series threshold in the series connection state.

4. The current interruption device according to claim 1 or 2, wherein the control unit determines whether the battery is connected in series or in parallel based on the battery voltage.

5. The current interruption device according to claim 1 or 2, wherein the control unit determines whether the connection is in series or parallel based on the current in the conductive path which switches between a state in which current flows and a state in which no current flows in the series connection and the parallel connection.

6. The current interruption device according to claim 1 or 2, wherein the battery is housed in a battery pack case, and the first interruption unit, the second interruption unit, and the control unit are housed in the case.

7. The current interruption device according to claim 1 or 2, wherein the control unit comprises a first control circuit and a second control circuit separate from the first control circuit, the first control circuit controls the first interruption unit, and the second control circuit controls the second interruption unit.

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