Vehicle-mounted switching device

Abstract

To provide an on-vehicle switching device which switches plural batteries between a series connection state and a parallel connection state and more securely blocks a conducting path that is permissible to flow current in the series connection state.SOLUTION: An on-vehicle switching device 1 has: a changeover circuit 14; a first conducting path 11 through which current can flow in a series connection state and does not flow in a parallel connection state; a second conducting path 12 through which current can flow in the parallel connection state and does not flow in the series connection state; a third conducting path 13 which forms a path between a negative electrode of a first battery 10A and a positive electrode of a second battery 10B in the series connection state and forms a path between both positive electrodes or both negative electrodes of the first battery 10A and the second battery 10B in the parallel connection state; and a fuse part 14D which is provided on the first conducting path 11 and blocks the first conducting path 11 based on an external signal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an in-vehicle switching device. [Background technology]

[0002] The vehicle power supply device disclosed in Patent Document 1 is a device that can connect a first power storage means and a second power storage means in series or in parallel. In this vehicle power supply device, when the first power storage means and the second power storage means are connected in series to the inverter, the control means turns on the third switch means to energize one charging resistor. After energization, the control device turns on the first switch means to form a circuit for connecting them in series. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-274830 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle power supply device of Patent Document 1, if a conductive path connecting the first power storage means and the second power storage means in series is short-circuited, there is a concern that the conductive path may not be interrupted even by turning off the first switch means. Conventional techniques have not taken any measures to address such concerns.

[0005] Therefore, the present disclosure aims to more reliably cut off the conduction path through which current is allowed to flow in the series connection state in an in-vehicle switching device that switches multiple batteries between a series connection state and a parallel connection state. [Means for solving the problem]

[0006] In the present disclosure, an in-vehicle switching device for a vehicle includes: An in-vehicle switching device for use in an in-vehicle power supply system, the in-vehicle switching device including a battery section having at least a first battery and a second battery, and a switching circuit configured to switch between a series connection state in which the first battery and the second battery are connected in series and a parallel connection state in which the first battery and the second battery are connected in parallel, The switching circuit; a first conductive path that is a path through which a current is allowed to flow in the series connection state and through which a current does not flow in the parallel connection state; a second conductive path that is a path through which a current is allowed to flow in the parallel connection state and through which a current does not flow in the series connection state; a third conductive path that forms a path between the negative electrode of the first battery and the positive electrode of the second battery in the series connection state, and that forms a path between both positive electrodes or both negative electrodes of the first battery and the second battery in the parallel connection state; a fuse portion provided in the first conductive path and configured to interrupt the first conductive path based on an external signal; has. Effect of the Invention

[0007] The in-vehicle switching device of the present disclosure is configured to switch multiple batteries between a series connection state and a parallel connection state, and aims to forcibly cut off a conduction path through which current is allowed to flow when in a series connection state. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram conceptually showing an in-vehicle power supply system including an in-vehicle switching device according to the first embodiment. [Diagram 2] 2 is a schematic diagram showing a state in which a series switch is inadvertently turned on in the parallel connection state in the in-vehicle power supply system of FIG. 1. FIG. [Diagram 3] 2 is a schematic diagram showing a state in which a power supply path is short-circuited in a parallel connection state in the in-vehicle power supply system of FIG. 1. FIG. [Figure 4]2 is a schematic diagram showing a state in which a second parallel switch is in an on state in the in-vehicle power supply system of FIG. 1 in a series connection state. FIG. [Diagram 5] 2 is a schematic diagram showing a state in which power is supplied from a battery unit to a load in a parallel connection state in the in-vehicle power supply system of FIG. 1. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following describes exemplary embodiments of the present disclosure. The following features [1] to [6] may be combined in any manner that is not inconsistent.

[0010] [1] The in-vehicle switching device disclosed herein is used in an in-vehicle power supply system including a battery section having at least a first battery and a second battery, and a switching circuit that switches between a series connection state in which the first battery and the second battery are connected in series and a parallel connection state in which the first battery and the second battery are connected in parallel. The in-vehicle switching device includes the switching circuit, a first conductive path that is a path through which a current is allowed to flow in the series connection state and through which a current is not allowed to flow in the parallel connection state, a second conductive path that is a path through which a current is allowed to flow in the parallel connection state and through which a current is not allowed to flow in the series connection state, a third conductive path that is a path between the negative electrode of the first battery and the positive electrode of the second battery in the series connection state and is a path between both positive electrodes or both negative electrodes of the first battery and the second battery in the parallel connection state, and a fuse section that is provided in the first conductive path and that performs an operation of cutting off the first conductive path based on an external signal.

[0011] In the in-vehicle switching device of [1] above, even if a current flows through the first conductive path due to an inadvertent operation of the switching circuit or a short circuit failure during parallel connection and the first conductive path cannot be interrupted even by the switching circuit, the fuse unit can be caused to perform an interrupting operation based on an external signal. This allows the in-vehicle switching device to more reliably interrupt the first conductive path.

[0012] [2] The in-vehicle switching device according to [1] may further include a current detection unit that detects a current in the third conductive path. The fuse unit may perform an operation to cut off the first conductive path based on a current detected by the current detection unit.

[0013] The in-vehicle switching device described in [2] above can detect the current in the third conductive path (current between the batteries) by the current detection unit. Therefore, the in-vehicle switching device can cut off the first conductive path by the fuse unit based on the current generated between the batteries.

[0014] [3] In the in-vehicle switching device of [2] above, the fuse unit can perform an operation to interrupt the first conductive path based on an interruption signal output by the control unit when the current detected by the current detection unit satisfies a predetermined condition.

[0015] The in-vehicle switching device described in [3] above can interrupt the first conductive path by the fuse portion after determining whether or not the current in the third conductive path satisfies a predetermined condition.

[0016] [4] In the in-vehicle switching device according to any one of [1] to [3] above, a control unit may be provided that outputs a cutoff signal to the fuse unit when a current in the third conductive path satisfies a predetermined condition. The fuse unit may perform an operation to cut off the first conductive path when the cutoff signal is output from the control unit.

[0017] The in-vehicle switching device described in [4] above can interrupt the first conductive path based on the judgment of a control unit provided within the device (judgment of whether or not the current in the third conductive path satisfies a specified condition), and therefore can complete the interruption operation within the device.

[0018] [5] In the above-mentioned in-vehicle switching device [1] to [4], the in-vehicle power supply system may have a power path that is a path for transmitting power from the battery unit in both a series connection state and a parallel connection state. The in-vehicle switching device may have an external fuse unit that is provided in the power path and has a function of cutting off the current flowing through the power path.

[0019] The in-vehicle switching device described in [5] above can protect the device by cutting off the flow of electricity to the power path using the external fuse unit even if a ground fault or short circuit occurs in the power path when the device is connected in parallel.

[0020] [6] In the in-vehicle switching device of [5] above, the external fuse section can perform an operation of cutting off the flow of electricity to the power path based on an external signal.

[0021] The in-vehicle switching device described in [6] above can forcibly cut off the fuse unit provided in the power path based on an external signal. Therefore, the in-vehicle switching device can cut off the current in the power path more easily than a configuration provided with a thermal fuse or the like that cuts off when the cut-off characteristic (rated current) is satisfied. [Details of the embodiment of the present disclosure]

[0022] <Embodiment 1> FIG. 1 illustrates an in-vehicle power supply system 100 provided with an in-vehicle switching device 1 according to the first embodiment. A vehicle 110 includes the in-vehicle power supply system 100 and a load R (e.g., a motor for driving wheels). The in-vehicle power supply system 100 is used as a power supply for operating the load R of the vehicle in which it is installed. The in-vehicle power supply system 100 includes a battery section 10, a high-potential side conductive path 16, a low-potential side conductive path 17, an in-vehicle switching device 1, a power path 20, a junction box section 2, and a power supply path 30. The battery section 10 includes a first battery 10A and a second battery 10B. The in-vehicle switching device 1 includes a first conductive path 11, a second conductive path 12, a third conductive path 13, a switching circuit 14, a current detection section 14H, and a control section 50. The in-vehicle switching device 1 is used in the in-vehicle power supply system 100.

[0023] [Battery section configuration] The first battery 10A and the second battery 10B in the battery section 10 include a plurality of battery sections each formed as a unit cell, and the battery sections are integrally combined. The battery sections are not shown. In each of the first battery 10A and the second battery 10B, the electrode with the highest potential among the plurality of unit cells electrically connected in series is the positive electrode BH, and the electrode with the lowest potential among the plurality of unit cells electrically connected in series is the negative electrode BL.

[0024] In the present disclosure, "electrically connected" preferably means a configuration in which the connection objects are connected in a mutually conductive state (a state in which a current can flow) so that the potentials of both connection objects are equal. However, this is not limited to this configuration. For example, "electrically connected" may mean a configuration in which the two connection objects are connected in a state in which the two connection objects can be conductive with an electric component interposed between them.

[0025] [Configuration of high-potential side conductive path and low-potential side conductive path] One end of the high potential side conductive path 16 is electrically connected to the positive electrode BH of the first battery 10A. One end of the low potential side conductive path 17 is electrically connected to the negative electrode BL of the second battery 10B.

[0026] [Configuration of in-vehicle switching device] The second conductive path 12 allows a current to flow when the first battery 10A and the second battery 10B are electrically connected in parallel (hereinafter, also simply referred to as a parallel connection state). The second conductive path 12 is a path through which no current flows when the first battery 10A and the second battery 10B are electrically connected in series (hereinafter, also simply referred to as a series connection state). The second conductive path 12 includes a positive electrode-to-positive electrode conductive path 12A and a negative electrode-to-negative electrode conductive path 12B. One end of the positive electrode-to-positive electrode conductive path 12A is electrically connected to the other end of the high potential side conductive path 16. One end of the negative electrode-to-negative electrode conductive path 12B is electrically connected to the other end of the low potential side conductive path 17. The positive electrode conductive path 12A is a path through which a current flows between the positive electrode BH of the second battery 10B and the positive electrode BH of the first battery 10A in the parallel connection state, and is a path through which a current flows between the positive electrode BH of the second battery 10B and the positive electrode BH of the first battery 10A in the series connection state. The negative electrode conductive path 12B is a path through which a current flows between the negative electrode BL of the second battery 10B and the negative electrode BL of the first battery 10A in the parallel connection state, and is a path through which a current flows between the negative electrode BL of the second battery 10B and the negative electrode BL of the first battery 10A in the series connection state.

[0027] The third conductive path 13 forms a path between the negative electrode BL of the first battery 10A and the positive electrode BH of the second battery 10B in the series connection state, and forms a path between the positive electrodes BH or between the negative electrodes BL of the first battery 10A and the second battery 10B in the parallel connection state. The third conductive path 13 includes a first common path 13A and a second common path 13B. One end of the first common path 13A is electrically connected to the positive electrode BH of the second battery 10B. The other end of the first common path 13A is electrically connected to the other end of the positive electrode-to-positive electrode conductive path 12A. One end of the second common path 13B is electrically connected to the negative electrode BL of the first battery 10A. The other end of the second common path 13B is electrically connected to the other end of the negative electrode-to-negative electrode conductive path 12B.

[0028] The high-potential side conductive path 16, the positive-electrode conductive path 12A, and the first common path 13A form paths that connect the positive electrodes BH of the first battery 10A and the second battery 10B in the parallel connection state. In other words, the first common path 13A is a conductive path that connects the positive electrodes BH of the first battery 10A and the second battery 10B in the parallel connection state. The low-potential side conductive path 17, the negative-electrode conductive path 12B, and the second common path 13B form paths that connect the negative electrodes BL of the first battery 10A and the second battery 10B in the parallel connection state. In other words, the second common path 13B is a conductive path that connects the negative electrodes BL of the first battery 10A and the second battery 10B in the parallel connection state.

[0029] The first conductive path 11 is a path through which a current is allowed to flow in the series connection state and through which a current does not flow in the parallel connection state. One end of the first conductive path 11 is electrically connected to the other end of the second common path 13B and the other end of the negative electrode conductive path 12B. The other end of the first conductive path 11 is electrically connected to the other end of the first common path 13A and the other end of the positive electrode conductive path 12A. That is, the first conductive path 11 is electrically connected in series to the first battery 10A and the second battery 10B via the first common path 13A and the second common path 13B. The first conductive path 11 is a path through which a current does not flow between the positive electrode BH of the second battery 10B and the negative electrode BL of the first battery 10A in the parallel connection state.

[0030] [Switching circuit configuration] The switching circuit 14 has a function of switching between a series connection state in which the first battery 10A and the second battery 10B are connected in series and a parallel connection state in which they are connected in parallel. The switching circuit 14 has a first parallel switch 14A, a second parallel switch 14B, a series switch 14C, and a fuse unit 14D.

[0031] The first parallel switch 14A, the second parallel switch 14B, and the series switch 14C are configured, for example, by a relay switch or a semiconductor switch such as a MOSFET. The first parallel switch 14A is provided to be interposed in the positive-electrode conductive path 12A. The second parallel switch 14B is provided to be interposed in the negative-electrode conductive path 12B. The series switch 14C is provided to be interposed in the first conductive path 11. The first parallel switch 14A, the second parallel switch 14B, and the series switch 14C are configured to be switched between an on state and an off state by, for example, a control unit 50 described later.

[0032] The fuse unit 14D is disposed in the first conductive path 11 so as to be in series with the series switch 14C. In the first conductive path 11, the fuse unit 14D is located on the other end side of the series switch 14C. The fuse unit 14D performs an operation to cut off the first conductive path 11 based on an external signal (for example, a cutoff signal output from the control unit 50). The fuse unit 14D is configured as, for example, a pyrofuse, a semiconductor switch, or the like. The pyrofuse ignites gunpowder based on, for example, an external signal, and instantly generates an explosive force to rupture the first conductive path 11. The semiconductor switch is configured, for example, by a MOSFET, a GaNFET, a bipolar transistor, an IGBT, or the like, and allows the first conductive path 11 to pass electricity by an ON operation based on an external signal, and cuts off the first conductive path 11 by an OFF operation based on an external signal.

[0033] The control unit 50 is configured as, for example, an information processing device having a calculation function and an information processing function. The control unit 50 may be configured as a microcomputer or other information processing device. The control unit 50 switches the first parallel switch 14A, the second parallel switch 14B, and the series switch 14C to an ON state or an OFF state by a control signal. The control unit 50 also outputs a cutoff signal to the fuse unit 14D when the current of the third conductive path 13 (current detected by a current detection unit 14H described later) satisfies a predetermined condition. The case where the predetermined condition is satisfied is, for example, a case where the cutoff characteristic of the fuse unit 14D preset by the control unit 50 is satisfied. The cutoff characteristic defines, for example, what current value and how long the current must flow to cut off the path. The control unit 50 determines that the predetermined condition is satisfied when the current value detected by the current detection unit 14H described later becomes a preset current value and the current value continues to flow for a preset time.

[0034] [Current detection section configuration] The current detection unit 14H has a first detection unit 14F and a second detection unit 14G. The first detection unit 14F is provided to be interposed in the first common path 13A. The second detection unit 14G is provided to be interposed in the second common path 13B. The first detection unit 14F and the second detection unit 14G have, for example, a resistor and a differential amplifier, and are configured to be able to output a value indicating the current flowing through each of the first common path 13A and the second common path 13B (specifically, an analog voltage corresponding to the value of the current flowing through the first common path 13A and the second common path 13B) as a current value. The first detection unit 14F detects the state of the current flowing through the first common path 13A, and the second detection unit 14G detects the state of the current flowing through the second common path 13B. The current values ​​output from the first detection unit 14F and the second detection unit 14G are configured to be able to be input to the control unit 50, for example. That is, the current detection unit 14H detects the current flowing through the first common path 13A (the third conductive path 13) and the second common path 13B (the third conductive path 13).

[0035] [Junction box configuration] The junction box unit 2 has a function of supplying power from the battery unit 10 to the load R, etc. The junction box unit 2 has a high-potential side power path 20A which is a power path 20, a low-potential side power path 20B which is a power path 20, a high-potential side switch 20D, a bypass unit 20C, a low-potential side switch 20E, an external fuse unit 20K, a high-potential side power supply path 30A which is a power supply path 30, a low-potential side power supply path 30B which is a power supply path 30, a first power supply switch 30C, and a second power supply switch 30D.

[0036] The power path 20 is a path for transmitting power from the battery unit 10 in both a series connection state and a parallel connection state. One end of the high-potential side power path 20A is electrically connected to the other end of the high-potential side conductive path 16 and one end of the positive-electrode conductive path 12A. One end of the low-potential side power path 20B is electrically connected to the other end of the low-potential side conductive path 17 and one end of the negative-electrode conductive path 12B.

[0037] The high potential side switch 20D is provided in the high potential side power path 20A. The bypass unit 20C is provided electrically connected in parallel to the high potential side switch 20D. The bypass unit 20C has a bypass switch 20G and a resistor 20H. The bypass switch 20G and the resistor 20H are electrically connected in series. The bypass switch 20G is provided between the resistor 20H and the high potential side conductive path 16.

[0038] The low potential side switch 20E is provided in the low potential side power path 20B. The high potential side switch 20D, the bypass switch 20G, and the low potential side switch 20E are each configured by, for example, a relay switch or a semiconductor switch such as a MOSFET.

[0039] The external fuse unit 20K is provided in the power path 20 and has a function of cutting off the current flow through the power path 20. The external fuse unit 20K is provided on the low potential side power path 20B opposite the low potential side conductive path 17, sandwiching the low potential side switch 20E. The external fuse unit 20K performs an operation of cutting off the current flow through the power path 20 based on an external signal. The external fuse unit 20K is configured as, for example, a pyro-fuse, a semiconductor switch, or the like. The pyro-fuse ignites gunpowder based on, for example, an external signal, and instantly generates an explosive force to break the power path 20. The semiconductor switch is configured, for example, by a MOSFET, a GaNFET, a bipolar transistor, an IGBT, or the like, and allows the current flow through the power path 20 by an ON operation based on an external signal, and cuts off the power path 20 by an OFF operation based on an external signal. A load R is electrically connected between the other end side of the high potential side power path 20A and the other end side of the low potential side power path 20B.

[0040] The power supply path 30 is electrically connected to the power path 20. One end of the high-potential side power supply path 30A, which is the power supply path 30, is electrically connected between the bypass section 20C in the high-potential side power path 20A and the load R. One end of the low-potential side power supply path 30B, which is the power supply path 30, is electrically connected between the external fuse section 20K in the low-potential side power path 20B and the load R. Terminals 30E and 30F are provided at the other end of the high-potential side power supply path 30A and the other end of the low-potential side power supply path 30B, respectively. An external power source 40 can be electrically connected to the terminals 30E and 30F. The external power source 40 supplies power to the power path 20. The first power supply switch 30C is provided interposed in the high-potential side power supply path 30A. The second power supply switch 30D is provided interposed in the low-potential side power supply path 30B.

[0041] [When the switching circuit is connected in parallel] A parallel connection state in which the first battery 10A and the second battery 10B of the battery unit 10 are electrically connected in parallel during charging will be described. In this case, the first external power source 41 is connected to the terminals 30E and 30F, and a first voltage (e.g., 400 V) is applied to the battery unit 10 using a first charging method, a first current (e.g., 400 A) is applied to the battery unit 10, and a first power (e.g., 150 kW) is supplied. For example, as shown in FIG. 2, the control unit 50 switches the first parallel switch 14A and the second parallel switch 14B to the on state and switches the series switch 14C to the off state. This brings the first battery 10A and the second battery 10B into a state electrically connected in parallel. In this way, the switching circuit 14 is brought into a parallel connection state. Then, the high potential side switch 20D and the low potential side switch 20E are switched to the ON state, and the first power supply switch 30C and the second power supply switch 30D are switched to the ON state, so that power is supplied from the first external power source 41 to the battery unit 10. At this time, the high potential side conductive path 16, the positive electrode conductive path 12A, and the first common path 13A form a path for conducting between the positive electrodes BH of the first battery 10A and the second battery 10B. At the same time, the low potential side conductive path 17, the negative electrode conductive path 12B, and the second common path 13B form a path for conducting between the negative electrodes BL of the first battery 10A and the second battery 10B.

[0042] At this time, the first detection unit 14F provided in the first common path 13A detects the current flowing through the first common path 13A as a current value A. At the same time, the second detection unit 14G provided in the second common path 13B detects the current flowing through the second common path 13B as a current value C.

[0043] For example, the first detection unit 14F and the second detection unit 14G detect the currents in the first common path 13A and the second common path 13B as current values ​​A and C at the same time. Then, the detected current values ​​A and C are input to the control unit 50 at the same time. The control unit 50 adds the current values ​​A and C. The current value B, which is the result of the addition, corresponds to the current flowing in the low-potential side power path 20B (high-potential side power path 20A). The current value B thus obtained is a value at the same time when the first detection unit 14F and the second detection unit 14G detect the currents in the first common path 13A and the second common path 13B. In this way, the control unit 50 can grasp the magnitude of the current flowing in the low-potential side power path 20B as the current value B based on the current values ​​C and A corresponding to the magnitude of the current flowing in the second common path 13B and the first common path 13A.

[0044] The control unit 50 is configured to be able to monitor whether the magnitude of the current flowing through the first common path 13A (positive-electrode conductive path 12A) and the magnitude of the current flowing through the second common path 13B (negative-electrode conductive path 12B) have reached a predetermined threshold value. For example, when the series switch 14C is inadvertently switched to an on state or a short circuit occurs, and the first conductive path 11 cannot be cut off even by the switching circuit 14, if the control unit 50 determines that the current through the third conductive path 13 satisfies a predetermined condition (when the control unit 50 determines that the magnitude of the current flowing through at least one of the first common path 13A and the second common path 13B has reached a predetermined threshold value), the control unit 50 causes the fuse unit 14D to cut off the current flowing through the power path 20. The case where the predetermined condition is satisfied is, for example, a case where the cutoff characteristic of the fuse unit 14D preset by the control unit 50 is satisfied. The cutoff characteristic defines, for example, a current value and a duration for which the path is cut off. The control unit 50 determines that the specified condition is satisfied when the current value detected by the current detection unit 14H (at least one of the first detection unit 14F and the second detection unit 14G) becomes a predetermined current value and the current flows at that current value for a predetermined period of time.

[0045] In addition, even if a ground fault, short circuit, or the like occurs in the power path 20, the power supply path 30, or the like during the parallel connection state, the control unit 50 can cut off the current flow through the power path 20 by the external fuse unit 20K. When the control unit 50 determines that the current through the third conductive path 13 satisfies a predetermined condition (when the control unit 50 determines that the magnitude of the current flowing through at least one of the first common path 13A and the second common path 13B has reached a predetermined threshold), the control unit 50 causes the external fuse unit 20K to cut off the current flow through the power path 20. For example, as shown in FIG. 3, when a short circuit occurs in the power supply path 30, the control unit 50 causes the external fuse unit 20K to cut off the current flow through the power path 20. The case where the predetermined condition is satisfied is, for example, a case where the cutoff characteristic of the external fuse unit 20K preset by the control unit 50 is satisfied. The cutoff characteristic defines, for example, a current value and a time for which a path is cut off. The control unit 50 determines that the specified condition is satisfied when the current value detected by the current detection unit 14H (at least one of the first detection unit 14F and the second detection unit 14G) becomes a predetermined current value and the current flows at that current value for a predetermined period of time.

[0046] [When the switching circuit is in series connection] A case of a series connection state in which the first battery 10A and the second battery 10B of the battery unit 10 are electrically connected in series during charging will be described. In this case, the second external power source 42 is connected to the terminals 30E and 30F, and a second voltage (e.g., 800 V) higher than the first voltage is applied to the battery unit 10 using a second charging method, a second current (e.g., 400 A) is applied to the battery unit 10, and a second power (e.g., 350 kW) is supplied. For example, as shown in FIG. 4, the control unit 50 switches the first parallel switch 14A and the second parallel switch 14B to the OFF state and switches the series switch 14C to the ON state. This brings the first battery 10A and the second battery 10B into a state electrically connected in series. In this way, the switching circuit 14 is brought into a series connection state. Then, the high potential side switch 20D and the low potential side switch 20E are switched to the ON state, and the first power supply switch 30C and the second power supply switch 30D are switched to the ON state, and power is supplied from the second external power source 42 to the battery section 10.

[0047] At this time, the first detection unit 14F provided in the first common path 13A detects the current flowing through the first common path 13A as a current value F, and the second detection unit 14G provided in the second common path 13B detects the current flowing through the second common path 13B as a current value G. The first detection unit 14F and the second detection unit 14G detect the currents in the first common path 13A and the second common path 13B, for example, at the same time. Then, the current values ​​F and G are input to the control unit 50 at the same time. The first battery 10A and the second battery 10B are electrically connected in series. Therefore, the current values ​​F and G are the same value. The current flowing through the low-potential side power path 20B (high-potential side power path 20A) is also the same value as the current value F (current value G). In this way, the control unit 50 can grasp the magnitude of the current generated from the battery unit 10 as the current values ​​F and G.

[0048] The control unit 50 is configured to monitor whether or not the magnitude of the current flowing through the third conductive path 13 (first conductive path 11) has reached a predetermined threshold. For example, as shown in FIG. 4, when the second parallel switch 14B is inadvertently switched to the on state and the first conductive path 11 cannot be cut off even by the switching circuit 14, if the control unit 50 determines that the current through the third conductive path 13 satisfies a predetermined condition (when the control unit 50 determines that the magnitude of the current flowing through the first common path 13A has reached a predetermined threshold), the control unit 50 causes the fuse unit 14D to cut off the current flowing through the power path 20. The case where the predetermined condition is satisfied is, for example, a case where the cutoff characteristic of the fuse unit 14D preset by the control unit 50 is satisfied. The cutoff characteristic defines, for example, the current value and duration of the current flow required to cut off the path. The control unit 50 determines that the specified condition is satisfied when the current value detected by the current detection unit 14H (at least one of the first detection unit 14F and the second detection unit 14G) becomes a predetermined current value and the current flows at that current value for a predetermined period of time.

[0049] [Power supply to load] A case where the load R operates will be described. When the load R operates, for example, the first battery 10A and the second battery 10B of the battery section 10 are electrically connected in parallel. In this case, for example, as shown in FIG. 5, the control section 50 switches the first parallel switch 14A and the second parallel switch 14B to the ON state and switches the series switch 14C to the OFF state. As a result, the first battery 10A and the second battery 10B are electrically connected in parallel. In this way, the switching circuit 14 is brought into a parallel connection state. Then, after this, the high potential side switch 20D and the low potential side switch 20E are switched to the ON state, and the first power supply switch 30C and the second power supply switch 30D are switched to the OFF state, so that power is supplied from the battery section 10 to the load R. At this time, the high potential side conductive path 16, the positive electrode conductive path 12A, and the first common path 13A form paths that conduct electricity between the positive electrodes BH of the first battery 10A and the second battery 10B. Together with this, the low potential side conductive path 17, the negative electrode conductive path 12B, and the second common path 13B form a path that provides electrical continuity between the negative electrodes BL of the first battery 10A and the second battery 10B.

[0050] Next, the effects of the configuration according to the present disclosure will be illustrated. The in-vehicle switching device 1 of the present disclosure can cause the fuse portion 14D to perform an interrupting operation based on an external signal even in a case where a current flows through the first conductive path 11 due to an inadvertent operation of the switching circuit 14 or a short circuit failure during a parallel connection state, and the first conductive path 11 cannot be interrupted even by the switching circuit 14. This allows the in-vehicle switching device 1 to interrupt the first conductive path 11 more reliably.

[0051] The in-vehicle switching device 1 of the present disclosure can detect the current (current between the batteries) in the third conductive path 13 by the current detection unit 14H. Therefore, the in-vehicle switching device 1 can interrupt the first conductive path 11 by the fuse unit 14D based on the current generated between the batteries.

[0052] In the in-vehicle switching device 1 of the present disclosure, the fuse unit 14D performs an operation of interrupting the first conductive path 11 based on an interruption signal output by the control unit 50 when the current detected by the current detection unit 14H satisfies a predetermined condition. The in-vehicle switching device 1 can interrupt the first conductive path 11 by the fuse unit 14D after determining whether or not the current in the third conductive path 13 satisfies a predetermined condition.

[0053] The in-vehicle switching device 1 of the present disclosure has a control unit 50 that outputs a cutoff signal to the fuse unit 14D when the current in the third conductive path 13 satisfies a predetermined condition. The fuse unit 14D performs an operation to cut off the first conductive path 11 when the cutoff signal is output from the control unit 50. This allows the in-vehicle switching device 1 to cut off the first conductive path 11 based on the judgment of the control unit 50 provided therein (judgment as to whether the current in the third conductive path 13 satisfies a predetermined condition), and therefore the cutoff operation can be completed within the device.

[0054] The in-vehicle power supply system 100 of the present disclosure has a power path 20 which is a path for transmitting power from the battery unit 10 in both a series connection state and a parallel connection state. The in-vehicle switching device 1 has an external fuse unit 20K which is provided in the power path 20 and has a function of cutting off the current flow through the power path 20. As a result, even if a ground fault, short circuit, or the like occurs in the power path 20 or the like in the parallel connection state, the in-vehicle switching device 1 can protect the device by cutting off the current flow through the power path 20 using the external fuse unit 20K.

[0055] In the in-vehicle switching device 1 of the present disclosure, the external fuse unit 20K performs an operation to cut off the current flow through the power path 20 based on an external signal. This allows the in-vehicle switching device 1 to forcibly perform a cut-off operation on the fuse unit 14D provided in the power path 20 based on the external signal. Therefore, the in-vehicle switching device 1 can cut off the current flow through the power path 20 more easily than a configuration provided with a thermal fuse or the like that performs a cut-off operation when the cut-off characteristic (rated current) is satisfied.

[0056] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, the features of the above or later described embodiments can be combined in any combination within a range that does not contradict. In addition, any feature of the above or later described embodiments can be omitted unless it is clearly stated as essential. Furthermore, the above-mentioned embodiment may be modified as follows.

[0057] In the first embodiment, the external fuse unit 20K is configured to cut off the current flow through the power path 20 based on an external signal (pyrofuse, semiconductor switch), but may be configured, for example, as a thermal fuse, etc. The external fuse unit 20K melts according to its own cutoff characteristics (for example, rated current) to cut off the current flow through the low-potential side power path 20B.

[0058] In the first embodiment, the control unit 50 satisfies a predetermined condition (a condition for outputting a cutoff signal for the fuse unit 14D) when the preset cutoff characteristic of the fuse unit 14D is satisfied, but other configurations are also possible. For example, the predetermined condition may be satisfied when the current value of the current in the third conductive path 13 (current detected by the current detection unit 14H described below) reaches a predetermined threshold. In addition, the predetermined condition may be satisfied when the temperature detected by a temperature detection unit provided in the in-vehicle power supply system 100 (for example, the temperature of the battery unit 10) reaches a predetermined temperature (threshold).

[0059] In the first embodiment, the control unit 50 is provided in the in-vehicle switching device 1, but it may be provided in the in-vehicle power supply system or outside the in-vehicle power supply system.

[0060] In the first embodiment, an example is shown in which the load R operates when the battery unit 10 is in a parallel connection state, but the load R may operate when the battery unit 10 is in a series connection state, or the series connection state and parallel connection state of the battery unit 10 may be switched when the load R is operating.

[0061] In embodiment 1, a configuration is exemplified in which the fuse section 14D cuts off the flow of electricity to the power path 20 when the magnitude of the current flowing in at least one of the first common path 13A and the second common path 13B reaches a predetermined threshold when the battery section 10 is in a parallel connection state. However, the fuse section 14D may be configured to cut off the flow of electricity to the power path 20 when the magnitude of the current flowing in both the first common path 13A and the second common path 13B reaches a predetermined threshold.

[0062] In the first embodiment, the switching circuit switches the first battery 10A and the second battery 10B between a series connection state and a parallel connection state, but this is not limited to this, and the switching circuit may be configured to switch three or more batteries between a series connection state and a parallel connection state.

[0063] In the first embodiment, the current detection unit is configured to output a current value corresponding to the magnitude of the current flowing through the conductive path, but the current detection unit may be configured to use a comparator. In this case, the current detection unit determines whether the current value exceeds a threshold value, and when the current value exceeds the threshold value, outputs an over-threshold signal indicating that the current has exceeded the threshold value.

[0064] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0065] 1...In-vehicle switching device 2...Junction box section 10…Battery section 10A…First battery (battery section) 10B…Second battery (battery section) 11...First conductive path 12...Second conductive path 12A…Positive electrode conductive path (second conductive path) 12B: Negative electrode conductive path (second conductive path) 13…Third conductive path 13A...First common path (third conductive path) 13B...Second common path (third conductive path) 14...Switching circuit 14A…First parallel switch 14B…Second parallel switch 14C…Series switch 14D…Fuse section 14F…First detection section (current detection section) 14G…Second detection section (current detection section) 14H…Current detection section 16...High potential side conductive path 17...Low potential conductive path 20…Power line 20A…High-voltage power line 20B…Low potential side power path 20C…Bypass section 20D…High potential side switch 20E…Low potential switch 20F…External current detection section 20G…Bypass Switch 20H…Resistance 20K…External fuse section 30…Power supply line 30A…High potential side power supply path 30B…Low potential side power supply path 30C…First power supply switch 30D…Second power supply switch 30E, 30F…Terminals 40…External power supply 41…1st external power supply (external power supply) 42…Second external power supply (external power supply) 50...Control unit 100...Automotive power supply system 110…Vehicle A, B, C, F, G…Current value BH…Positive electrode BL…Negative electrode R…Load

Claims

1. An in-vehicle switching device for use in an in-vehicle power supply system including: a battery section having at least a first battery and a second battery; and a switching circuit that switches between a series connection state in which the first battery and the second battery are connected in series and a parallel connection state in which the first battery and the second battery are connected in parallel, The switching circuit; a first conductive path that is a path through which a current is allowed to flow in the series connection state and through which a current does not flow in the parallel connection state; a second conductive path that is a path through which a current is allowed to flow in the parallel connection state and through which a current does not flow in the series connection state; a third conductive path that forms a path between the negative electrode of the first battery and the positive electrode of the second battery in the series connection state, and that forms a path between both positive electrodes or both negative electrodes of the first battery and the second battery in the parallel connection state; a fuse portion provided in the first conductive path and configured to interrupt the first conductive path based on an external signal; a current detection unit that detects a current in the third conductive path; having The fuse unit performs an operation of interrupting the first conductive path based on the current detected by the current detection unit, the in-vehicle power supply system has a power path which is a path for transmitting power from the battery unit in both the series connection state and the parallel connection state, An external fuse portion is provided in the power path and has a function of cutting off current flow through the power path, The external fuse unit performs an operation of cutting off the current flow through the power path based on an external signal, The external fuse unit cuts off the current flow through the power path based on the current detected by the current detection unit. In-vehicle switching device.

2. The fuse unit performs an operation of interrupting the first conductive path based on an interruption signal output by a control unit when the current detected by the current detection unit satisfies a predetermined condition. The vehicle-mounted switching device according to claim 1 .

3. a control unit that outputs a disconnection signal to the fuse unit when the current in the third conductive path satisfies a predetermined condition; The fuse unit performs an operation of interrupting the first conductive path when the interruption signal is output from the control unit. The vehicle-mounted switching device according to claim 1 or 2.

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