Onboard power supply device

Abstract

An onboard power supply device (10) includes: a first switch unit (11) provided between a power supply unit (2) and a storage unit (3); a second switch unit (12) provided between the first switch unit (11) and the storage unit (3); an intermediate conductive path (35) provided between the first switch unit (11) and the second switch unit (12); and a relief terminal (17) connected to the intermediate conductive path (35). When the first switch unit (11) is in an ON state, current is allowed to flow from the power supply unit (2) side to the intermediate conductive path (35) side, and when the first switch unit (11) is in an OFF state, current is blocked from flowing from the power supply unit (2) side to the intermediate conductive path (35) side. When the second switch unit (12) is in an ON state, current is allowed to flow from the storage unit (3) side to the intermediate conductive path (35) side, and when the second switch unit (12) is in an OFF state, current is blocked from flowing from the storage unit (3) side to the intermediate conductive path (35) side.

Description

Vehicle-mounted power supply device

[0001] The present disclosure relates to a vehicle-mounted power supply device.

[0002] The power supply system disclosed in Patent Document 1 includes a first system and a second system as power systems. The first system includes a first power output unit, and the second system includes a second power output unit. The first power output unit and the second power output unit are each a power storage device. The power supply system includes a first path and a second path as main paths. The first path and the second path connect the first power output unit and the second power output unit.

[0003] Japanese Patent Application Laid-Open No. 2019-62727

[0004] In Patent Document 1, when the first power output unit or the second power output unit runs out of battery, it is necessary to get help from a battery outside the vehicle. However, depending on the position and structure of the battery, it may be difficult to directly connect a booster cable to the terminals of the battery that constitutes the first power output unit or the second power output unit. Therefore, it is conceivable to provide a rescue terminal for connecting an external battery to the first path or the second path. However, in this configuration, if the negative terminal of the external battery is accidentally connected to the rescue terminal, there is a risk of current flowing into the external battery.

[0005] An object of the present disclosure is to provide a technology capable of preventing current from flowing into an external battery.

[0006] The in-vehicle power supply device of the present disclosure comprises: a first switch unit provided between a power supply unit and a power storage unit; a second switch unit provided between the first switch unit and the power storage unit; an intermediate conductive path provided between the first switch unit and the second switch unit; and a rescue terminal connected to the intermediate conductive path, wherein the first switch unit, when in the ON state, allows current to flow from the power supply unit to the intermediate conductive path, and when in the OFF state, blocks the current flowing from the power supply unit to the intermediate conductive path; and the second switch unit, when in the ON state, allows current to flow from the power storage unit to the intermediate conductive path, and when in the OFF state, blocks the current flowing from the power storage unit to the intermediate conductive path.

[0007] According to the technology disclosed herein, it is possible to prevent current from flowing into an external battery.

[0008] Figure 1 is a schematic diagram showing an in-vehicle system 1 equipped with an in-vehicle power supply device 10 according to the first embodiment. Figure 2 is a conceptual diagram illustrating the current flow when the positive terminal 91 of the external battery 90 is connected to the rescue terminal 17. Figure 3 is a conceptual diagram illustrating the current flow when the third switch unit 13, the fourth switch unit 14, and the load-side switch unit 16A are switched to the ON state in the state shown in Figure 2. Figure 4 is a conceptual diagram illustrating the current flow when the power supply unit 2 starts supplying power in the state shown in Figure 3. Figure 5 is a conceptual diagram illustrating the current flow when the external battery 90 is disconnected from the rescue terminal 17 in the state shown in Figure 4. Figure 6 is a conceptual diagram illustrating the current flow when the first switch unit 11, the second switch unit 12, and the fifth switch unit 15 are switched to the ON state in the state shown in Figure 5. Figure 7 is a conceptual diagram illustrating the current flow when the negative terminal 92 of the external battery 90 is connected to the rescue terminal 17.

[0009] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described.

[0010] [1] An in-vehicle power supply device comprising: a first switch unit provided between a power supply unit and a power storage unit; a second switch unit provided between the first switch unit and the power storage unit; an intermediate conductive path provided between the first switch unit and the second switch unit; and a rescue terminal connected to the intermediate conductive path, wherein the first switch unit, when in the ON state, allows current to flow from the power supply unit to the intermediate conductive path, and when in the OFF state, blocks the current flowing from the power supply unit to the intermediate conductive path; and the second switch unit, when in the ON state, allows current to flow from the power storage unit to the intermediate conductive path, and when in the OFF state, blocks the current flowing from the power storage unit to the intermediate conductive path.

[0011] With the above configuration, power from the external battery is supplied to the vehicle's power supply device by connecting the positive terminal of the external battery to the rescue terminal. However, if the negative terminal of the external battery is mistakenly connected to the rescue terminal, there is a concern that current may flow from the power supply unit or energy storage unit to the external battery. However, with the above configuration, the first switch unit can prevent current from flowing from the power supply unit to the external battery, and the second switch unit can prevent current from flowing from the energy storage unit to the external battery.

[0012] [2] The in-vehicle power supply device according to [1], wherein the second switch unit, when in the ON state, allows current to flow from the intermediate conductive path side to the power storage unit side, and includes a control unit that starts up when an external battery is connected to the rescue terminal and receives power from the external battery, and the control unit switches the first switch unit and the second switch unit to the ON state when started up.

[0013] With the above configuration, by connecting an external battery to the rescue terminal, it is possible to allow current to flow from the power supply side to the energy storage side via the first switch section and the second switch section.

[0014] [3] The power supply unit starts supplying power when the external battery is connected to the rescue terminal, and the control unit, after being started up, switches the first switch unit and the second switch unit to the ON state when the external battery is disconnected from the rescue terminal by receiving power from the power supply unit. The vehicle power supply device as described in [2].

[0015] If the first and second switches are switched to the ON position while the external battery is connected to the rescue terminal, and power is supplied from the power supply unit to the energy storage unit, there is a risk that current from the power supply unit may flow into the external battery. With the above configuration, the control unit switches the first and second switches to the ON position after startup when the external battery is disconnected from the rescue terminal. Therefore, it is possible to allow current to flow from the power supply unit to the energy storage unit while preventing current from flowing from the power supply unit to the external battery.

[0016] [4] The power supply unit comprises a battery and a voltage conversion unit that performs a conversion operation to increase or decrease the voltage input from the battery and output it, and the power supply is provided by the voltage conversion unit performing the conversion operation, as described in [3].

[0017] With the above configuration, the output voltage of the power supply unit can be adjusted by the voltage conversion unit.

[0018] [5] An in-vehicle power supply device according to any one of [1] to [4], comprising: a third switch unit provided between the rescue terminal and the intermediate conductive path; a terminal-side conductive path provided between the third switch unit and the rescue terminal; a branch path branched from the terminal-side conductive path; and a control unit that, when an external battery is connected to the rescue terminal, receives power from the external battery via the branch path and is activated, wherein the third switch unit, when in the ON state, allows current to flow from the rescue terminal side to the intermediate conductive path side, and when in the OFF state, blocks the current flowing from the rescue terminal side to the intermediate conductive path side, the third switch unit is normally off type, and the control unit switches the third switch unit to the ON state when the voltage of the rescue terminal is within the normal range.

[0019] According to the above configuration, the third switch is in the off state before the control unit is started up. Therefore, even if an abnormal voltage is output from the external battery when it is connected to the rescue terminal, the third switch prevents the abnormal voltage from being output to the intermediate conductive path. Furthermore, after the external battery is connected to the rescue terminal and the control unit is started up, the third switch is switched to the on state if the voltage at the rescue terminal is within the normal range. This prevents the abnormal voltage from being output to the intermediate conductive path and allows a normal voltage to be output to the intermediate conductive path.

[0020] [6] The in-vehicle power supply device according to any one of [1] to [5], wherein the first switch section and the second switch section are FETs.

[0021] With the above configuration, when the first switch unit is in the off state, it is possible to allow current to flow from the intermediate conductive path side to the power supply unit side, and when the second switch unit is in the off state, it is possible to allow current to flow from the intermediate conductive path side to the energy storage unit side.

[0022] [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 is a system mounted on a vehicle. The in-vehicle system 1 comprises a power supply unit 2, an energy storage unit 3, loads 4A, 4B, 4C, 4D, 4E, 4F, and an in-vehicle power supply device 10. The power supply unit 2 and loads 4A, 4B, 4C constitute a first power supply system. The energy storage unit 3 and loads 4D, 4E, 4F constitute a second power supply system.

[0023] The power supply unit 2 includes a battery 2A, a voltage conversion unit 2B, and a relay 2C. The battery 2A is, for example, a high-voltage battery. The fully charged voltage of the battery 2A is greater than the fully charged voltage of the energy storage unit 3. The voltage conversion unit 2B performs a conversion operation to boost or step down the voltage input from the battery 2A and output it. The voltage conversion unit 2B is, for example, a DC-DC converter. The power supply unit 2 supplies power to the first conductive path 31 by the conversion operation of the voltage conversion unit 2B. The relay 2C is, for example, a system main relay. The relay 2C is installed between the battery 2A and the voltage conversion unit 2B. When the relay 2C is ON, it allows current to flow from the battery 2A to the voltage conversion unit 2B, and when it is OFF, it cuts off the current flowing from the battery 2A to the voltage conversion unit 2B. The relay 2C is a normally-off type.

[0024] The energy storage unit 3 is, for example, a low-voltage battery. The positive terminal of the energy storage unit 3 is electrically connected to the second conductive path 32. The negative terminal of the energy storage unit 3 is electrically connected to the ground 30.

[0025] The in-vehicle power supply device 10 includes a first switch unit 11, a second switch unit 12, a third switch unit 13, a fourth switch unit 14, a fifth switch unit 15, load-side switch units 16A, 16B, 16C, 16D, 16E, 16F, a rescue terminal 17, a ground terminal 18, a first conductive path 31, a second conductive path 32, an intermediate conductive path 35, a terminal-side conductive path 36, a first branch path 41, a second branch path 42, a third branch path 43, load-side conductive paths 44A, 44B, 44C, 44D, 44E, 44F, voltage detection units 51, 52, and a control unit 53.

[0026] The first switch section 11, the second switch section 12, the third switch section 13, the fourth switch section 14, the fifth switch section 15, and the load-side switch sections 16A, 16B, 16C, 16D, 16E, 16F (hereinafter also referred to as switch sections 11 to 16F) are, for example, FETs (Field Effect Transistors). Switch sections 11 to 16F are normally-off type.

[0027] The first switch unit 11 is provided between the power supply unit 2 and the energy storage unit 3. The second switch unit 12 is provided between the first switch unit 11 and the energy storage unit 3. A first conductive path 31 is provided between the first switch unit 11 and the power supply unit 2. A second conductive path 32 is provided between the second switch unit 12 and the energy storage unit 3. An intermediate conductive path 35 is provided between the first switch unit 11 and the second switch unit 12.

[0028] When the first switch unit 11 is in the ON state, it allows current to flow from the power supply unit 2 to the intermediate conductive path 35 through itself, and allows current to flow from the intermediate conductive path 35 to the power supply unit 2 through itself. When the first switch unit 11 is in the OFF state, it blocks the current flowing from the power supply unit 2 to the intermediate conductive path through itself, and allows current to flow from the intermediate conductive path 35 to the power supply unit 2 through itself.

[0029] When the second switch unit 12 is in the ON state, it allows current to flow from the energy storage unit 3 to the intermediate conductive path 35 through itself, and also allows current to flow from the intermediate conductive path 35 to the energy storage unit 3 through itself. When the second switch unit 12 is in the OFF state, it blocks the current flowing from the energy storage unit 3 to the intermediate conductive path 35 through itself, and also allows current to flow from the intermediate conductive path 35 to the energy storage unit 3 through itself.

[0030] The rescue terminal 17 is electrically connected to the intermediate conductive path 35. The rescue terminal 17 and the ground terminal 18 are electrically connected to the external battery 90. The ground terminal 18 is electrically connected to the ground 30.

[0031] The third switch unit 13 is provided between the rescue terminal 17 and the intermediate conductive path 35. When the third switch unit 13 is ON, it allows current to flow from the rescue terminal 17 to the intermediate conductive path 35 through itself, and also allows current to flow from the intermediate conductive path 35 to the rescue terminal 17 through itself. When the third switch unit 13 is OFF, it blocks the current flowing from the rescue terminal 17 to the intermediate conductive path 35 through itself, and also allows current to flow from the intermediate conductive path 35 to the rescue terminal 17 through itself.

[0032] The fourth switch unit 14 is provided in the first conductive path 31. When the fourth switch unit 14 is in the ON state, it allows current to flow from the first switch unit 11 to the power supply unit 2 through itself, and allows current to flow from the power supply unit 2 to the first switch unit 11 through itself. When the fourth switch unit 14 is in the OFF state, it blocks the current flowing from the first switch unit 11 to the power supply unit 2 through itself, and allows current to flow from the power supply unit 2 to the first switch unit 11 through itself.

[0033] The fifth switch unit 15 is provided in the second conductive path 32. When the fifth switch unit 15 is in the ON state, it allows current to flow from the second switch unit 12 to the energy storage unit 3 through itself, and allows current to flow from the energy storage unit 3 to the second switch unit 12 through itself. When the fifth switch unit 15 is in the OFF state, it blocks the current flowing from the second switch unit 12 to the energy storage unit 3 through itself, and allows current to flow from the energy storage unit 3 to the second switch unit 12 through itself.

[0034] The first branch line 41 branches off from the first conductive line 31 and is electrically connected to the control unit 53. The first branch line 41 branches off from the first conductive line 31 on the power supply unit 2 side of the fourth switch unit 14. The second branch line 42 branches off from the second conductive line 32 and is electrically connected to the control unit 53. The second branch line 42 branches off from the second conductive line 32 on the energy storage unit 3 side of the fifth switch unit 15. A terminal-side conductive line 36 is provided between the third switch unit 13 and the rescue terminal 17. The third branch line 43 branches off from the terminal-side conductive line 36 and is electrically connected to the control unit 53. The third branch line 43 is an example of a branch line.

[0035] Each of the load-side conductive paths 44A, 44B, and 44C branches off from the first conductive path 31 on the side of the first switch section 11 rather than the fourth switch section 14.

[0036] Load 4A is electrically connected to the first conductive path 31 via load-side conductive path 44A. A load-side switch unit 16A is provided on the load-side conductive path 44A. When the load-side switch unit 16A is ON, it allows current to flow from the first conductive path 31 to the load 4A through it. When the load-side switch unit 16A is OFF, it blocks the current flowing from the first conductive path 31 to the load 4A through it.

[0037] Load 4B is electrically connected to the first conductive path 31 via load-side conductive path 44B. A load-side switch unit 16B is provided in the load-side conductive path 44B. When the load-side switch unit 16B is ON, it allows current to flow from the first conductive path 31 to the load 4B through it. When the load-side switch unit 16B is OFF, it blocks the current flowing from the first conductive path 31 to the load 4B through it.

[0038] Load 4C is electrically connected to the first conductive path 31 via load-side conductive path 44C. A load-side switch unit 16C is provided on the load-side conductive path 44C. When the load-side switch unit 16C is ON, it allows current to flow from the first conductive path 31 to the load 4C through it. When the load-side switch unit 16C is OFF, it blocks the current flowing from the first conductive path 31 to the load 4C through it.

[0039] Each of the load-side conductive paths 44D, 44E, and 44F branches off from the second conductive path 32 on the side of the second switch section 12 rather than the fifth switch section 15.

[0040] Load 4D is electrically connected to the second conductive path 32 via load-side conductive path 44D. A load-side switch unit 16D is provided on the load-side conductive path 44D. When the load-side switch unit 16D is ON, it allows current to flow from the second conductive path 32 to the load 4D through it. When the load-side switch unit 16D is OFF, it blocks the current flowing from the second conductive path 32 to the load 4D through it.

[0041] Load 4E is electrically connected to the second conductive path 32 via the load-side conductive path 44E. A load-side switch section 16E is provided in the load-side conductive path 44E. When the load-side switch section 16E is in the on state, it allows current to flow from the second conductive path 32 side to the load 4E side through itself. When the load-side switch section 16E is in the off state, it blocks the current flowing from the second conductive path 32 side to the load 4E side through itself.

[0042] Load 4F is electrically connected to the second conductive path 32 via the load-side conductive path 44F. A load-side switch section 16F is provided in the load-side conductive path 44F. When the load-side switch section 16F is in the on state, it allows current to flow from the second conductive path 32 side to the load 4F side through itself. When the load-side switch section 16F is in the off state, it blocks the current flowing from the second conductive path 32 side to the load 4F side through itself.

[0043] The voltage detection unit 51 detects the voltage of the rescue terminal 17. The voltage detection unit 51 detects, for example, the voltage of the terminal-side conductive path 36. The voltage detection unit 52 detects the output voltage of the power supply unit 2. The output voltage of the power supply unit 2 is the output voltage of the voltage conversion unit 2B. The voltage detection unit 52 detects, for example, the voltage of the first conductive path 31 on the power supply unit 2 side rather than the fourth switch section 14. The voltage detection units 51 and 52 are configured by, for example, a known voltage detection circuit. The voltage detection units 51 and 52 output a signal indicating the detection result.

[0044] The control unit 53 is configured by, for example, a microcomputer. The microcomputer has a memory, a CPU, and the like. The control unit 53 is realized, for example, when the CPU executes a computer program stored in the memory. Note that the control unit 53 is not limited to the configuration realized by software in this way, and may be configured by hardware or a combination of software and hardware.

[0045] The control unit 53 specifies the voltage of the rescue terminal 17 based on the signal output from the voltage detection unit 51. The control unit 53 specifies the output voltage of the power supply unit 2 based on the signal output from the voltage detection unit 52.

[0046] The control unit 53 can receive power supply from the power supply unit 2 via the first branch path 41. The control unit 53 can receive power supply from the power storage unit 3 via the second branch path 42. When an external battery 90 is connected to the rescue terminal 17, the control unit 53 can receive power supply from the external battery 90 via the third branch path 43. When receiving power supply, the control unit 53 starts up. The control unit 53 controls the switch units 11 to 16F.

[0047] 1-2. Operating example of the in-vehicle system 1 The in-vehicle system 1 is a system capable of charging the power storage unit 3 using the external battery 90 when the vehicle fails to switch to the starting state due to insufficient charge of the power storage unit 3. Hereinafter, the operation when the power storage unit 3 is undercharged will be described.

[0048] In a state where the vehicle fails to switch to the starting state due to insufficient charge of the power storage unit 3, the power required for startup is not supplied from the power storage unit 3 to the control unit 53. Also, since the voltage conversion unit 2B stops and the relay 2C is also in the off state, the power required for startup is not supplied from the power supply unit 2 to the control unit 53 either. Therefore, the control unit 53 is maintained in the off state.

[0049] In this state, as shown in FIG. 2, the positive terminal 91 of the external battery 90 is connected to the rescue terminal 17 via the cable 93, and the negative terminal 92 of the external battery 90 is connected to the ground terminal 18 via the cable 94. Thereby, power is supplied from the external battery 90 to the control unit 53 via the terminal-side conductive path 36 and the third branch path 43, and the control unit 53 starts up.

[0050] When the control unit 53 is activated, it determines whether the voltage at the rescue terminal 17 is within the normal range. For example, the control unit 53 determines that the voltage at the rescue terminal 17 is within the normal range if it is below the overvoltage threshold. If the control unit 53 determines that the voltage at the rescue terminal 17 is not within the normal range, it keeps the third switch unit 13 in the off state. If the control unit 53 determines that the voltage at the rescue terminal 17 is within the normal range, it switches the third switch unit 13 and the load-side switch unit 16A to the on state, as shown in Figure 3. As a result, power is supplied from the external battery 90 to the load 4A. The control unit 53 also switches the fourth switch unit 14 to the on state.

[0051] In this embodiment, load 4A is an ECU that controls the power supply unit 2 (specifically, the voltage conversion unit 2B and the relay 2C). When load 4A starts up by receiving power from the external battery 90, it switches the relay 2C to the ON state, as shown in Figure 4, causing the voltage conversion unit 2B to perform the conversion operation. As a result, power from the power supply unit 2 is supplied to the first conductive path 31, and then supplied to the control unit 53 via the first conductive path 31. The current flowing from the power supply unit 2 is interrupted by the first switch unit 11 and is not supplied to the external battery 90.

[0052] If the external battery 90 is disconnected from the rescue terminal 17 in this state, the control unit 53 and load 4A maintain the running state by receiving power from the power supply unit 2, as shown in Figure 5.

[0053] After startup, the control unit 53 repeatedly determines whether the external battery 90 has been disconnected from the rescue terminal 17. For example, the control unit 53 determines whether the external battery 90 has been disconnected from the rescue terminal 17 based on the voltage of the rescue terminal 17. For example, the control unit 53 determines that the external battery 90 has been disconnected from the rescue terminal 17 when the voltage of the rescue terminal 17 falls below a connection determination threshold. The connection determination threshold is, for example, 0V.

[0054] When the control unit 53 determines that the external battery 90 has been disconnected from the rescue terminal 17, it switches the first switch unit 11, the second switch unit 12, and the fifth switch unit 15 to the ON state, as shown in Figure 6. As a result, power is supplied from the power supply unit 2 to the energy storage unit 3, and the energy storage unit 3 is charged.

[0055] 1-3. Effects of the On-board Power Supply Device 10 According to the on-board power supply device 10, power from the external battery 90 is supplied to the on-board power supply device 10 by connecting the positive terminal 91 of the external battery 90 to the rescue terminal 17 and the negative terminal 92 to the ground terminal 18. However, if, by mistake, as shown in Figure 7, the negative terminal 92 is connected to the rescue terminal 17 and the positive terminal 91 is connected to the ground terminal 18, there is a concern that current will flow from the power supply unit 2 or the energy storage unit 3 to the external battery 90. However, according to the on-board power supply device 10, the first switch unit 11 can prevent current from flowing from the power supply unit 2 to the external battery 90, and the second switch unit 12 can prevent current from flowing from the energy storage unit 3 to the external battery 90.

[0056] Furthermore, the control unit 53 starts up when the external battery 90 is connected to the rescue terminal 17 and receives power from the external battery 90. When the control unit 53 starts up, it switches the first switch unit 11, the second switch unit 12, and the fifth switch unit 15 to the ON state. With this configuration, when the external battery 90 is connected to the rescue terminal 17, it is possible to allow current to flow from the power supply unit 2 to the energy storage unit 3 via the first switch unit 11, the second switch unit 12, and the fifth switch unit 15.

[0057] Furthermore, the power supply unit 2 starts supplying power when the external battery 90 is connected to the rescue terminal 17. After startup, when the external battery 90 is disconnected from the rescue terminal 17, the control unit 53 receives power from the power supply unit 2 and switches the first switch unit 11 and the second switch unit 12 to the ON state. If the first switch unit 11 and the second switch unit 12 are switched to the ON state and power is supplied from the power supply unit 2 to the energy storage unit 3 while the external battery 90 is connected to the rescue terminal 17, there is a risk that current from the power supply unit 2 will flow into the external battery 90. With this configuration, after startup, when the external battery 90 is disconnected from the rescue terminal 17, the control unit 53 switches the first switch unit 11 and the second switch unit 12 to the ON state. Therefore, it is possible to allow current to flow from the power supply unit to the energy storage unit while avoiding current from the power supply unit 2 flowing into the external battery 90.

[0058] Furthermore, the power supply unit 2 includes a battery 2A and a voltage conversion unit 2B that performs a conversion operation to boost or lower the voltage input from the battery 2A and output it. Power is supplied by the voltage conversion unit 2B performing the conversion operation. With this configuration, the output voltage of the power supply unit 2 can be adjusted by the voltage conversion unit 2B.

[0059] Furthermore, the third switch unit 13 is in the off state before the control unit 53 is activated. Therefore, even if an abnormal voltage is output from the external battery 90 when it is connected to the rescue terminal 17, the third switch unit 13 prevents the abnormal voltage from being output to the intermediate conductive path 35. In addition, after the external battery 90 is connected to the rescue terminal 17 and activated, the control unit 53 switches the third switch unit 13 to the ON state if the voltage at the rescue terminal 17 is within the normal range. This prevents an abnormal voltage from being output to the intermediate conductive path 35 and allows a normal voltage to be output to the intermediate conductive path 35.

[0060] Furthermore, the first switch section 11 and the second switch section 12 are FETs. With this configuration, when the first switch section 11 is in the off state, it is possible to allow current to flow from the intermediate conductive path 35 to the power supply section 2, and when the second switch section 12 is in the off state, it is possible to allow current to flow from the intermediate conductive path 35 to the energy storage section 3.

[0061] <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.

[0062] In the first embodiment described above, the power supply unit 2 had a configuration that included a battery 2A and a voltage conversion unit 2B, but it may have a different configuration. For example, the power supply unit may have a configuration that includes an alternator.

[0063] If the external battery 90 is disconnected from the rescue terminal 17 before the power supply from the power supply unit 2 is sufficient, the control unit 53 will turn off. To avoid this situation, the user may be notified that the external battery 90 should not be removed when the power supply from the power supply unit 2 is insufficient. The determination of whether the power supply from the power supply unit 2 is sufficient may be made, for example, based on the output voltage of the power supply unit 2. For example, the control unit 53 may determine that the power supply from the power supply unit 2 is insufficient when the output voltage of the power supply unit 2 is below the target voltage, and determine that the power supply from the power supply unit 2 is sufficient when the output voltage of the power supply unit 2 is equal to or greater than the target voltage. When the control unit 53 determines whether the power supply from the power supply unit 2 is sufficient, it is preferable to keep the fourth switch unit 14 in the off state so that current from the external battery 90 does not flow into the power supply unit 2. In this case, the control unit 53 may, for example, switch the fourth switch unit 14 to the ON state at the same time that the first switch unit 11, the second switch unit 12, and the fifth switch unit 15 are switched to the ON state after the external battery 90 has been disconnected from the rescue terminal 17. Alternatively, when the power supply from the power supply unit 2 is sufficient, the control unit 53 may stop the notification prohibiting the removal of the external battery 90, or it may notify the user of information prompting the removal of the external battery 90. As a notification method, for example, the load 4B may be designated as the notification unit, and the control unit 53 may switch the load-side switch unit 16B to the ON state to make a notification from the notification unit. The notification unit may be, for example, a display or a speaker.

[0064] 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.

[0065] 1...In-vehicle system 2...Power supply unit 2A...Battery 2B...Voltage conversion unit 2C...Relay 3...Energy storage unit 4A...Load 4B...Load 4C...Load 4D...Load 4E...Load 4F...Load 10...In-vehicle power supply device 11...First switch unit 12...Second switch unit 13...Third switch unit 14...Fourth switch unit 15...Fifth switch unit 16A...Load-side switch unit 16B...Load-side switch unit 16C...Load-side switch unit 16D...Load-side switch unit 16E...Load-side switch unit 16F...Load-side switch unit 17...Rescue terminal 18...Ground terminal 30...Ground 31...First conductive path 32...Second conductive path 35...Intermediate conductive path 36...Terminal-side conductive path 41...First branch path 42...Second branch path 43...Third branch path (branch path) 44A...Load-side conductive path 44B...Load-side conductive path 44C...Load-side conductive path 44D...Load-side conductive path 44E...Load-side conductive path 44F...Load-side conductive path 51...Voltage detection unit 52...Voltage detection unit 53...Control unit 90...External battery 91...Positive terminal 92...Negative terminal 93...Cable 94...Cable

Claims

1. An in-vehicle power supply device comprising: a first switch unit provided between a power supply unit and a power storage unit; a second switch unit provided between the first switch unit and the power storage unit; an intermediate conductive path provided between the first switch unit and the second switch unit; and a rescue terminal connected to the intermediate conductive path, wherein the first switch unit, when in the ON state, allows current to flow from the power supply unit to the intermediate conductive path, and when in the OFF state, blocks the current flowing from the power supply unit to the intermediate conductive path; and the second switch unit, when in the ON state, allows current to flow from the power storage unit to the intermediate conductive path, and when in the OFF state, blocks the current flowing from the power storage unit to the intermediate conductive path.

2. The in-vehicle power supply device according to claim 1, wherein the second switch unit, when in the ON state, allows current to flow from the intermediate conductive path side to the power storage unit side, and includes a control unit that starts up when an external battery is connected to the rescue terminal and receives power from the external battery, and the control unit switches the first switch unit and the second switch unit to the ON state when started up.

3. The in-vehicle power supply device according to claim 2, wherein the power supply unit starts supplying power when the external battery is connected to the rescue terminal, and the control unit, after starting up, switches the first switch unit and the second switch unit to the ON state when the external battery is disconnected from the rescue terminal by receiving power from the power supply unit.

4. The in-vehicle power supply device according to claim 3, wherein the power supply unit comprises a battery and a voltage conversion unit that performs a conversion operation to increase or decrease the voltage input from the battery and output it, and the voltage conversion unit supplies power by performing the conversion operation.

5. An in-vehicle power supply device according to any one of claims 1 to 4, comprising: a third switch unit provided between the rescue terminal and the intermediate conductive path; a terminal-side conductive path provided between the third switch unit and the rescue terminal; a branch path branched from the terminal-side conductive path; and a control unit that, when an external battery is connected to the rescue terminal, receives power from the external battery via the branch path and is activated, wherein the third switch unit, when in the ON state, allows current to flow from the rescue terminal side to the intermediate conductive path side, and when in the OFF state, blocks the current flowing from the rescue terminal side to the intermediate conductive path side, the third switch unit is of the normally-off type, and the control unit switches the third switch unit to the ON state when the voltage of the rescue terminal is within the normal range.

6. The in-vehicle power supply device according to any one of claims 1 to 4, wherein the first switch section and the second switch section are FETs.

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