On-vehicle control device

Abstract

An on-vehicle control device (40) has: a first switch unit (41) provided to a third conductive path (33); a second switch unit (42) provided to a sixth conductive path (36); and a control unit (61) for controlling the first switch unit (41) and the second switch unit (42). The control unit (61) monitors the voltage of a first low-voltage battery (11) and the voltage of a second low-voltage battery (21), and controls the first switch unit (41) and the second switch unit (42) on the basis of the voltage of the first low-voltage battery (11) and the voltage of the second low-voltage battery (21).

Description

In-vehicle control device

[0001] The present disclosure relates to an in-vehicle control device.

[0002] Patent Document 1 discloses a vehicle power supply system. This vehicle power supply system includes a main power supply system, a backup power supply system connected to the main power supply system, and a high-voltage power supply system. The high-voltage power supply system is connected to the main power supply system and the backup power supply system via a step-down device. The main power supply system includes a main low-voltage power supply and a normal load. The backup power supply system includes a backup power supply unit and an important emergency load. The backup power supply unit includes a backup low-voltage power supply.

[0003] This vehicle power supply system is capable of charging the main low-voltage power supply of the main power supply system with power from the high-voltage power supply system via a step-down device. This vehicle power supply system is also capable of charging the backup low-voltage power supply of the backup power supply system with power from the high-voltage power supply system via the step-down device. Charging of the backup low-voltage power supply is enabled by turning on a switch provided between the backup low-voltage power supply and the step-down device.

[0004] Japanese Patent Application Laid-Open No. 2022-151139

[0005] However, the configuration of Patent Document 1 has a problem in that it is not possible to charge only the main low-voltage power supply out of the main low-voltage power supply and the backup low-voltage power supply.

[0006] An object of the present disclosure is to provide a technique that makes it possible to selectively charge each battery of two low-voltage power supply systems that are connected to a high-voltage power supply system via a voltage conversion unit.

[0007] The in-vehicle control device of the present disclosure is an in-vehicle control device included in an in-vehicle system including: a high-voltage power supply; a voltage conversion unit that steps down a voltage input from the high-voltage power supply and outputs the stepped-down voltage to a first conductive path; a first low-voltage battery; a first load; a second conductive path having one end connected to the first conductive path; a third conductive path branching from the other end of the second conductive path and connected to the first low-voltage battery; a fourth conductive path branching from the other end of the second conductive path and connected to the first load; a second low-voltage battery; a second load; a fifth conductive path having one end connected to the first conductive path; a sixth conductive path branching from the other end of the fifth conductive path and connected to the second low-voltage battery; and a seventh conductive path branching from the other end of the fifth conductive path and connected to the second load, and the in-vehicle control device has: a first switch unit provided in the third conductive path; a second switch unit provided in the sixth conductive path; and a control unit that controls the first switch unit and the second switch unit, The first switch unit allows current to flow through itself toward the first low-voltage battery when in an on state, and blocks current from flowing through itself toward the first low-voltage battery when in an off state; the second switch unit allows current to flow through itself toward the second low-voltage battery when in an on state, and blocks current from flowing through itself toward the second low-voltage battery when in an off state; and the control unit monitors the voltage of the first low-voltage battery and the voltage of the second low-voltage battery, and controls the first switch unit and the second switch unit based on the voltage of the first low-voltage battery and the voltage of the second low-voltage battery.

[0008] According to the technique of the present disclosure, it is possible to selectively charge each battery of two low-voltage power supply systems connected to a high-voltage power supply system via a voltage conversion unit.

[0009] FIG. 1 is a schematic diagram illustrating an in-vehicle system according to a first embodiment. FIG. 2 is an explanatory diagram illustrating an in-vehicle system in a first state. FIG. 3 is an explanatory diagram illustrating an in-vehicle system in a second state. FIG. 4 is an explanatory diagram illustrating an in-vehicle system in a third state. FIG. 5 is an explanatory diagram illustrating an in-vehicle system in a fourth state. FIG. 6 is an explanatory diagram illustrating an in-vehicle system in a fifth state. FIG. 7 is an explanatory diagram illustrating an in-vehicle system in a sixth state. FIG. 8 is an explanatory diagram illustrating an in-vehicle system in a seventh state. FIG. 9 is an explanatory diagram illustrating an in-vehicle system in an eighth state. FIG. 10 is an explanatory diagram illustrating an in-vehicle system in a ninth state. FIG. 11 is an explanatory diagram illustrating an in-vehicle system in a tenth state. FIG. 12 is an explanatory diagram illustrating an in-vehicle system in an eleventh state. FIG. 13 is an explanatory diagram illustrating an in-vehicle system in a twelfth state. FIG. 14 is an explanatory diagram illustrating an in-vehicle system in a thirteenth state. FIG. 15 is an explanatory diagram illustrating an in-vehicle system in a fourteenth state.

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

[0011] [1] An on-board control device included in an on-board system including a high-voltage power supply, a voltage conversion unit that steps down a voltage input from the high-voltage power supply and outputs the stepped-down voltage to a first conductive path, a first low-voltage battery, a first load, a second conductive path having one end connected to the first conductive path, a third conductive path branching from the other end of the second conductive path and connected to the first low-voltage battery, a fourth conductive path branching from the other end of the second conductive path and connected to the first load, a second low-voltage battery, a second load, a fifth conductive path having one end connected to the first conductive path, a sixth conductive path branching from the other end of the fifth conductive path and connected to the second low-voltage battery, and a seventh conductive path branching from the other end of the fifth conductive path and connected to the second load, the on-board control device having a first switch unit provided in the third conductive path, a second switch unit provided in the sixth conductive path, and a control unit that controls the first switch unit and the second switch unit, an on-board control device, wherein the first switch unit allows current to flow to the first low-voltage battery through itself when in an on state, and blocks current from flowing to the first low-voltage battery through itself when in an off state; the second switch unit allows current to flow to the second low-voltage battery through itself when in an on state, and blocks current from flowing to the second low-voltage battery through itself when in an off state; and the control unit monitors the voltage of the first low-voltage battery and the voltage of the second low-voltage battery, and controls the first switch unit and the second switch unit based on the voltage of the first low-voltage battery and the voltage of the second low-voltage battery.

[0012] In the above-described in-vehicle system, a first low-voltage power supply system is formed by the first low-voltage battery and the first load, and a second low-voltage power supply system is formed by the second low-voltage battery and the second load. When power is supplied from a high-voltage power supply to the first conduction path via a voltage converter, the in-vehicle control device controls the first switch unit to an on state and the second switch unit to an off state, thereby charging only the first low-voltage battery of the first low-voltage power supply system. Furthermore, when power is supplied from a high-voltage power supply to the first conduction path via a voltage converter, the in-vehicle control device controls the first switch unit to an off state and the second switch unit to an on state, thereby charging only the second low-voltage battery of the second low-voltage power supply system. In other words, the in-vehicle control device can selectively charge the first low-voltage battery of the first low-voltage power supply system and the second low-voltage battery of the second low-voltage power supply system.

[0013] [2] The in-vehicle control device according to [1], comprising: a third switch unit provided in the second conductive path; and a fourth switch unit provided in the fifth conductive path, wherein the third switch unit, when in an on state, allows current to flow from the first low-voltage battery side to the first conductive path side and the fifth conductive path side through itself, and when in an off state, blocks current to flow from the first low-voltage battery side to the first conductive path side and the fifth conductive path side through itself; the fourth switch unit, when in an on state, allows current to flow from the second low-voltage battery side to the first conductive path side and the second conductive path side through itself, and when in an off state, blocks current to flow from the second low-voltage battery side to the first conductive path side and the second conductive path side through itself; and the control unit controls the third switch unit and the fourth switch unit.

[0014] The in-vehicle control device can prevent current from flowing from the first low-voltage battery to the high-voltage power supply side or the second low-voltage power supply system side by controlling the third switch unit to the off state, and can prevent current from flowing from the second low-voltage battery to the high-voltage power supply side or the first low-voltage power supply system side by controlling the fourth switch unit to the off state.

[0015] [3] The vehicle control device described in [2], wherein the control unit controls the third switch unit and the fourth switch unit to an off state when an abnormality occurs in the power supply from the voltage conversion unit to the first conduction path.

[0016] When an abnormality occurs in the power supply from the voltage conversion unit, the above-mentioned vehicle control device can operate independently using the first low-voltage power supply system and the second low-voltage power supply system by controlling the third switch unit and the fourth switch unit to the off state.

[0017] [4] The vehicle control device described in [2] or [3], wherein at least one of a load required for the vehicle to run, a load required for changing the direction of travel of the vehicle, and a load required for stopping the vehicle is included in each of the first load and the second load.

[0018] At least one of a load necessary for the vehicle to travel, a load necessary for changing the direction of travel of the vehicle, and a load necessary for stopping the vehicle is provided in each of the first low-voltage power supply system and the second low-voltage power supply system. Therefore, even if an abnormality occurs in either the first low-voltage power supply system or the second low-voltage power supply system, the on-board control device can perform at least one of the operations of traveling, changing the direction of travel, and stopping the vehicle by using the low-voltage power supply system that is not experiencing an abnormality.

[0019] [5] The first load includes a first general load and a first important load having a higher importance than the first general load; the second load includes a second general load and a second important load having a higher importance than the second general load; the first important load and the second important load each include at least one of a load necessary for the vehicle to run, a load necessary for changing the direction of travel of the vehicle, and a load necessary for stopping the vehicle; the fourth conductive path includes a first branch path connected to the first general load and a second branch path connected to the first important load; the seventh conductive path includes a third branch path connected to the second general load and a fourth branch path connected to the second important load; and the power supply further includes a fifth switch unit provided in the first branch path, a sixth switch unit provided in the second branch path, a seventh switch unit provided in the third branch path, and an eighth switch unit provided in the fourth branch path. The in-vehicle control device according to [4], wherein the fifth switch unit allows current to flow to the first general load side through itself when in an on state and blocks current flow to the first general load side through itself when in an off state; the sixth switch unit allows current to flow to the first important load side through itself when in an on state and blocks current flow to the first important load side through itself when in an off state; the seventh switch unit allows current to flow to the second general load side through itself when in an on state and blocks current flow to the second general load side through itself when in an off state; the eighth switch unit allows current to flow to the second important load side through itself when in an on state and blocks current flow to the second important load side through itself when in an off state; and the control unit controls the fifth switch unit, the sixth switch unit, the seventh switch unit, and the eighth switch unit.

[0020] The vehicle-mounted control device can selectively cut off power supply to the first general load, the first important load, the second general load, and the second important load.

[0021] [6] An on-board control device according to any one of [1] to [5], comprising: an electrical connection box provided between the voltage conversion unit and the first load and the second load; the first low-voltage battery; and the second low-voltage battery, wherein the electrical connection box is electrically connected to the voltage conversion unit, the first load, and the second load; and the first switch unit, the second switch unit, the control unit, the first low-voltage battery, and the second low-voltage battery are housed within the electrical connection box.

[0022] The above-mentioned vehicle control device can be made smaller by accommodating the first switch unit, the second switch unit, the control unit, the first low-voltage battery, and the second low-voltage battery together in a single electrical connection box.

[0023] [7] The vehicle-mounted control device according to any one of [1] to [6], wherein the control unit is configured by one ECU.

[0024] The above-described in-vehicle control device can more quickly perform processing in accordance with the results of monitoring the battery voltage than a configuration in which the processing performed by the control unit is distributed among a plurality of ECUs.

[0025] [Details of the embodiment of the present disclosure] 1. First embodiment 1-1. Configuration of in-vehicle system 1 The in-vehicle system 1 shown in Fig. 1 is a system mounted on a vehicle. The in-vehicle system 1 includes a high-voltage power supply 2, a voltage conversion unit 3, a first low-voltage battery 11, a first load 12, a second low-voltage battery 21, and a second load 22.

[0026] The high-voltage power supply 2 is, for example, a high-voltage battery or a generator (e.g., a motor generator). The high-voltage battery is, for example, a lithium-ion battery. The high-voltage power supply 2 constitutes a high-voltage power supply system.

[0027] The first low-voltage battery 11 is a battery whose voltage when fully charged is lower than that of the high-voltage power supply 2. The first low-voltage battery 11 is configured as, for example, a lead battery. The first low-voltage battery 11 and the first load 12 configure a first low-voltage power supply system.

[0028] The second low-voltage battery 21 is a battery whose voltage when fully charged is lower than that of the high-voltage power supply 2. The output voltage of the second low-voltage battery 21 when fully charged may be the same as or different from the output voltage of the first low-voltage battery 11 when fully charged. The second low-voltage battery 21 is configured as, for example, a lithium-ion battery. The second low-voltage battery 21 and the second load 22 configure a second low-voltage power supply system.

[0029] The voltage conversion unit 3 is configured as, for example, a step-down DC-DC converter. The voltage conversion unit 3 is provided between the high-voltage power supply system and the first and second low-voltage power supply systems. Specifically, the voltage conversion unit 3 is provided between the high-voltage power supply 2 and the first and second low-voltage batteries 11 and 21. The voltage conversion unit 3 performs a step-down operation to step down the voltage input from the high-voltage power supply 2 and output it to the first and second low-voltage batteries 11 and 21.

[0030] The first load 12 includes a first general load 13 and a first important load 14 that is more important than the first general load 13. The second load 22 includes a second general load 23 and a second important load 24 that is more important than the second general load 23.

[0031] At least one of a load necessary for the vehicle to travel, a load necessary for changing the direction of travel of the vehicle, and a load necessary for stopping the vehicle is included in each of the first important load 14 and the second important load 24. The load necessary for the vehicle to travel is, for example, an eAxle, an engine ECU, a hybrid ECU, an EV ECU, an in-wheel motor, etc. The load necessary for changing the direction of travel of the vehicle is, for example, an electric power steering, a steer-by-wire, etc. The load necessary for stopping the vehicle is, for example, an electric brake, an electric parking brake, a brake-by-wire, etc. The first important load 14 and the second important load 24 may include a load necessary for autonomous driving. The load necessary for autonomous driving is, for example, an autonomous driving ECU, an autonomous driving sensor, a meter, etc.

[0032] The first general load 13 and the second general load 23 are loads that are not necessary for the vehicle to travel, change the direction of travel of the vehicle, stop the vehicle, or for automatic driving. For example, the first general load 13 and the second general load 23 are headlights, car navigation systems, audio equipment, etc.

[0033] The in-vehicle system 1 includes a first conductive path 31 , a second conductive path 32 , a third conductive path 33 , a fourth conductive path 34 , a fifth conductive path 35 , a sixth conductive path 36 , and a seventh conductive path 37 .

[0034] The voltage converter 3 is electrically connected to one end of the first conductive path 31. A voltage stepped down by the voltage converter 3 is applied to the first conductive path 31. The second conductive path 32 branches off from the other end of the first conductive path 31. One end of the second conductive path 32 is electrically connected to the first conductive path 31. The third conductive path 33 branches off from the other end of the second conductive path 32 and is electrically connected to the high-potential terminal of the first low-voltage battery 11. The fourth conductive path 34 branches off from the other end of the second conductive path 32 and is electrically connected to the first load 12. The fourth conductive path 34 includes a first branch path 34A electrically connected to the first general load 13 and a second branch path 34B electrically connected to the first important load 14.

[0035] The fifth conductive path 35 branches off from the other end of the first conductive path 31. One end of the fifth conductive path 35 is electrically connected to the first conductive path 31. The sixth conductive path 36 branches off from the other end of the fifth conductive path 35 and is electrically connected to the high-potential terminal of the second low-voltage battery 21. The seventh conductive path 37 branches off from the other end of the fifth conductive path 35 and is electrically connected to the second load 22. The seventh conductive path 37 includes a third branch path 37A electrically connected to the second general load 23 and a fourth branch path 37B electrically connected to the second important load 24.

[0036] 1-2. Configuration of the Vehicle Control Device 40 The vehicle system 1 includes the vehicle control device 40. The vehicle control device 40 has a first switch unit 41, a second switch unit 42, a third switch unit 43, a fourth switch unit 44, a fifth switch unit 45, a sixth switch unit 46, a seventh switch unit 47, and an eighth switch unit 48. In the example shown in FIG. 1 , each of the switch units 41 to 48 is configured with a semiconductor switch (specifically, a MOSFET), but may also be configured with a mechanical switch. Furthermore, each of the switch units 41 to 48 may be configured with two semiconductor switches butted together.

[0037] The first switch unit 41 is provided on the third conductive path 33. When the first switch unit 41 is in an ON state, it allows current to flow through itself toward the first low-voltage battery 11, and when the first switch unit 41 is in an OFF state, it blocks current from flowing through itself toward the first low-voltage battery 11.

[0038] The second switch unit 42 is provided on the sixth conductive path 36. When the second switch unit 42 is in an ON state, it allows current to flow through itself toward the second low-voltage battery 21, and when the second switch unit 42 is in an OFF state, it blocks current from flowing through itself toward the second low-voltage battery 21.

[0039] The third switch unit 43 is provided on the second conductive path 32. When the third switch unit 43 is in an ON state, it allows current to flow from the first low-voltage battery 11 side to the first conductive path 31 side and the fifth conductive path 35 side through itself, and when the third switch unit 43 is in an OFF state, it blocks current from flowing from the first low-voltage battery 11 side to the first conductive path 31 side and the fifth conductive path 35 side through itself.

[0040] The fourth switch unit 44 is provided on the fifth conductive path 35. When in an ON state, the fourth switch unit 44 allows current to flow from the second low-voltage battery 21 side to the first conductive path 31 side and the second conductive path 32 side through itself, and when in an OFF state, blocks current from flowing from the second low-voltage battery 21 side to the first conductive path 31 side and the second conductive path 32 side through itself.

[0041] The fifth switch unit 45 is provided in the first branch path 34A. When the fifth switch unit 45 is in an on state, it allows a current to flow through itself to the first general load 13 side, and when the fifth switch unit 45 is in an off state, it blocks the current from flowing through itself to the first general load 13 side.

[0042] The sixth switch unit 46 is provided in the second branch path 34B. When the sixth switch unit 46 is in an ON state, it allows current to flow through itself to the first important load 14, and when the sixth switch unit 46 is in an OFF state, it blocks current from flowing through itself to the first important load 14.

[0043] The seventh switch unit 47 is provided in the third branch path 37A. When the seventh switch unit 47 is in an on state, it allows current to flow through itself to the second general load 23, and when it is in an off state, it blocks current from flowing through itself to the second general load 23.

[0044] The eighth switch unit 48 is provided in the fourth branch path 37B. When the eighth switch unit 48 is in an on state, it allows current to flow through itself to the second important load 24, and when it is in an off state, it blocks current from flowing through itself to the second important load 24.

[0045] The onboard control device 40 includes detection units 51, 52, 53, 54, 55, 56, and 57 and a control unit 61. The detection unit 51 includes, for example, a known voltage detection circuit and detects the voltage of the first low-voltage battery 11. The detection unit 51 includes, for example, a known current sensor and detects the current supplied to the first low-voltage battery 11. The detection unit 52 includes, for example, a known voltage detection circuit and detects the voltage of the second low-voltage battery 21. The detection unit 52 includes, for example, a known current sensor and detects the current supplied to the second low-voltage battery 21. The detection unit 53 includes, for example, a known voltage detection circuit and detects the voltage of the first branch path 34A. The detection unit 53 includes, for example, a known current sensor and detects the current flowing through the first branch path 34A. The detection unit 54 includes, for example, a known voltage detection circuit and detects the voltage of the second branch path 34B. The detection unit 54 includes, for example, a known current sensor and detects the current flowing through the second branch path 34B. The detection unit 55 includes, for example, a known voltage detection circuit and detects the voltage of the third branch path 37A. The detection unit 55 includes, for example, a known current sensor and detects the current flowing through the third branch path 37A. The detection unit 56 includes, for example, a known voltage detection circuit and detects the voltage of the fourth branch path 37B. The detection unit 56 includes, for example, a known current sensor and detects the current flowing through the fourth branch path 37B. The detection unit 57 includes, for example, a known voltage detection circuit and detects the voltage of the first conductive path 31. The detection unit 57 includes, for example, a known current sensor and detects the current flowing through the first conductive path 31. Information indicating the detection results by the detection units 51 to 57 is input to the control unit 61.

[0046] The control unit 61 includes, for example, a microcomputer and is configured by one ECU. The control unit 61 controls the voltage conversion unit 3 and the switches 41 to 48.

[0047] The on-board control device 40 has an electric connection box 62. The electric connection box 62 is, for example, a junction box. The electric connection box 62 is provided between the voltage conversion unit 3 and the first load 12 and the second load 22. The electric connection box 62 is electrically connected to the voltage conversion unit 3, the first load 12, and the second load 22. The first low-voltage battery 11, the second low-voltage battery 21, the switch units 41 to 48, the detection units 51 and 52, and the control unit 61 are housed in the electric connection box 62.

[0048] 1-3. Operation of the In-Vehicle System 1 As shown in Fig. 2, the in-vehicle system 1 can be in a first state in which power is supplied from the voltage conversion unit 3, the first low-voltage battery 11, and the second low-voltage battery 21 to the first load 12 and the second load 22. The in-vehicle system 1 is in the first state when, for example, the control unit 61 controls the switch units 41 to 48 to the on state while the voltage conversion unit 3 is performing a step-down operation. Note that the switch units 41 to 44 may also be in the off state. The in-vehicle system 1 is in the first state, for example, while the vehicle is running.

[0049] A vehicle can be in three states: running, stopped, and parked. Running refers to a state in which the starter switch is on and the vehicle speed is greater than zero. Stopped refers to a state in which the starter switch is on and the vehicle speed is zero. Parked refers to a state in which the starter switch is off. The starter switch is, for example, an ignition switch or a power switch. The control unit 61 determines whether the vehicle is running, stopped, or parked based on information received from, for example, an external ECU.

[0050] The control unit 61 controls the in-vehicle system 1 to the first state when the first low-voltage battery 11 satisfies a first discharge condition and the second low-voltage battery 21 satisfies a second discharge condition. The first discharge condition may be, for example, that the voltage of the first low-voltage battery 11 is equal to or higher than a predetermined first discharge lower limit voltage, or that the SOC (State of Charge) of the first low-voltage battery 11 is equal to or higher than a predetermined first percentage. The second discharge condition may be, for example, that the voltage of the second low-voltage battery 21 is equal to or higher than a predetermined second discharge lower limit voltage, or that the SOC of the second low-voltage battery 21 is equal to or higher than a predetermined second percentage.

[0051] As shown in Fig. 3, the in-vehicle system 1 can be in a second state in which the first low-voltage battery 11 and the second low-voltage battery 21 are simultaneously charged. The in-vehicle system 1 is in the second state, for example, when the control unit 61 controls the switches 41 to 48 to be in the on state while the voltage conversion unit 3 is performing a step-down operation to output a voltage higher than the voltage of the first low-voltage battery 11 and the voltage of the second low-voltage battery 21. Note that the switches 43 to 48 may also be in the off state. The in-vehicle system 1 is in the second state, for example, while the vehicle is traveling.

[0052] The control unit 61 controls the in-vehicle system 1 to the second state when the first low-voltage battery 11 satisfies a first charging condition and the second low-voltage battery 21 satisfies a second charging condition. The first charging condition may be, for example, that the voltage of the first low-voltage battery 11 is less than a fully charged voltage, or that the SOC of the first low-voltage battery 11 is less than 100%. The second charging condition may be, for example, that the voltage of the second low-voltage battery 21 is less than a fully charged voltage, or that the SOC of the second low-voltage battery 21 is less than 100%. The fully charged voltages of the first low-voltage battery 11 and the second low-voltage battery 21 are, for example, the same as the target voltages when the voltage conversion unit 3 performs a step-down operation.

[0053] As shown in Fig. 4, the in-vehicle system 1 can be in a third state in which only the first low-voltage battery 11 is charged out of the first low-voltage battery 11 and the second low-voltage battery 21. The in-vehicle system 1 enters the third state when, for example, the voltage conversion unit 3 is performing a step-down operation to output a voltage higher than the voltage of the first low-voltage battery 11 and the control unit 61 controls the switch units 41, 43 to 48 to the on state and the second switch unit 42 to the off state. Note that the switch units 43 to 48 may also be in the off state. The in-vehicle system 1 enters the third state, for example, while the vehicle is traveling.

[0054] For example, the control unit 61 controls the in-vehicle system 1 to the third state when the first low-voltage battery 11 satisfies the first charging condition and the second low-voltage battery 21 does not satisfy the second charging condition. The control unit 61 may also control the in-vehicle system 1 to the third state when the first low-voltage battery 11 satisfies the first charging condition and the second low-voltage battery 21 satisfies the second charging condition. For example, the control unit 61 may control the in-vehicle system 1 to the third state when the voltage of the first low-voltage battery 11 is lower than the voltage of the second low-voltage battery 21 by a predetermined value or more. In this case, the control unit 61 can preferentially charge the first low-voltage battery 11, which has a relatively lower voltage. The control unit 61 may also control the in-vehicle system 1 to the third state when the SOC of the first low-voltage battery 11 is lower than the SOC of the second low-voltage battery 21 by a predetermined value or more. In this case, the control unit 61 can preferentially charge the first low-voltage battery 11, which has a relatively lower SOC.

[0055] As shown in Fig. 5, the in-vehicle system 1 can be in a fourth state in which only the second low-voltage battery 21 of the first low-voltage battery 11 and the second low-voltage battery 21 is charged. The in-vehicle system 1 is in the fourth state, for example, when the control unit 61 controls the switches 42 to 48 to the on state and the first switch 41 to the off state while the voltage conversion unit 3 is performing a step-down operation to output a voltage higher than the voltage of the second low-voltage battery 21. Note that the switches 43 to 48 may also be in the off state. The in-vehicle system 1 is in the fourth state, for example, while the vehicle is traveling.

[0056] For example, the control unit 61 controls the in-vehicle system 1 to the fourth state when the first low-voltage battery 11 does not satisfy the first charging condition and the second low-voltage battery 21 satisfies the second charging condition. The control unit 61 may also control the in-vehicle system 1 to the fourth state when the first low-voltage battery 11 satisfies the first charging condition and the second low-voltage battery 21 satisfies the second charging condition. For example, the control unit 61 may control the in-vehicle system 1 to the fourth state when the voltage of the second low-voltage battery 21 is lower than the voltage of the first low-voltage battery 11 by a predetermined value or more. In this case, the control unit 61 can preferentially charge the second low-voltage battery 21, which has a relatively lower voltage. The control unit 61 may also control the in-vehicle system 1 to the fourth state when the SOC of the second low-voltage battery 21 is lower than the SOC of the first low-voltage battery 11 by a predetermined value or more. In this case, the control unit 61 can preferentially charge the second low-voltage battery 21, which has a relatively lower SOC.

[0057] 6, the in-vehicle system 1 can be in a fifth state in which power is supplied to the first load 12 and the second load 22 only from the first low-voltage battery 11 and the second low-voltage battery 21. The in-vehicle system 1 is in the fifth state when, for example, the control unit 61 controls the switch units 41 to 48 to the on state while the voltage conversion unit 3 is stopped. The in-vehicle system 1 is in the fifth state, for example, while the vehicle is parked.

[0058] 7, the in-vehicle system 1 can be in a sixth state in which power is supplied to the first load 12 and the second load 22 only from the second low-voltage battery 21. The in-vehicle system 1 is in the sixth state when, for example, the voltage conversion unit 3 is stopped and the control unit 61 controls the switch units 42 to 48 to the on state and the first switch unit 41 to the off state. The in-vehicle system 1 is in the sixth state, for example, while the vehicle is parked.

[0059] 8, the in-vehicle system 1 can be in a seventh state in which power is supplied to the first load 12 and the second load 22 only from the first low-voltage battery 11. The in-vehicle system 1 is in the seventh state when, for example, the voltage conversion unit 3 is stopped and the control unit 61 controls the switch units 41, 43 to 48 to the on state and controls the second switch unit 42 to the off state. The in-vehicle system 1 is in the seventh state, for example, while the vehicle is parked.

[0060] For example, if an abnormality occurs in the power supply from the voltage conversion unit 3 to the first conduction path 31 while the in-vehicle system 1 is in the first state, the in-vehicle system 1 enters the eighth state shown in FIG. The eighth state is a state in which the first low-voltage battery 11 supplies power to the first load 12 while preventing current from flowing from the first low-voltage battery 11 to the high-voltage power supply system and the second low-voltage power supply system, and the second low-voltage battery 21 supplies power to the second load 22 while preventing current from flowing from the second low-voltage battery 21 to the high-voltage power supply system and the first low-voltage power supply system. For example, when the control unit 61 determines that an abnormality has occurred in the power supply from the voltage conversion unit 3 to the first conduction path 31, the control unit 61 controls the switches 41, 42, 45-48 to the on state and the switches 43 and 44 to the off state. This places the in-vehicle system 1 in the eighth state. The control unit 61 determines that an abnormality has occurred in the power supply from the voltage conversion unit 3 to the first conduction path 31, for example, when it determines that the voltage of the first conduction path 31 is below a low voltage threshold (e.g., 0 V) ​​despite the voltage conversion unit 3 performing a step-down operation, when it determines that the current flowing through the first conduction path 31 has exceeded an overcurrent threshold despite the voltage conversion unit 3 performing a step-down operation, or when it determines that the current flowing through the first conduction path 31 is below a low current threshold (e.g., 0 A) despite the voltage conversion unit 3 performing a step-down operation.

[0061] For example, if an abnormality occurs in the power supply from the first low-voltage battery 11 while the in-vehicle system 1 is in the first state, the in-vehicle system 1 enters a ninth state shown in FIG. 10 . In the ninth state, power is supplied to the first load 12 and the second load 22 only from the voltage converter 3 and the second low-voltage battery 21. For example, if the control unit 61 determines that an abnormality exists in the power supply from the first low-voltage battery 11, the control unit 61 controls the switches 42 to 48 to the on state and the first switch 41 to the off state. This causes the in-vehicle system 1 to enter the ninth state. For example, the control unit 61 determines that an abnormality exists in the power supply from the first low-voltage battery 11 when the control unit 61 determines that the voltage of the first low-voltage battery 11 is equal to or lower than a low-voltage threshold (e.g., 0 V), when the control unit 61 determines that the current supplied to the first low-voltage battery 11 exceeds an overcurrent threshold, or when the control unit 61 determines that the current supplied to the first low-voltage battery 11 is equal to or lower than a low-current threshold (e.g., 0 A).

[0062] For example, if an abnormality occurs in the power supply from the second low-voltage battery 21 while the in-vehicle system 1 is in the first state, the in-vehicle system 1 enters a tenth state shown in FIG. 11 . In the tenth state, power is supplied to the first load 12 and the second load 22 only from the voltage conversion unit 3 and the first low-voltage battery 11. For example, if the control unit 61 determines that an abnormality exists in the power supply from the second low-voltage battery 21, the control unit 61 controls the switches 41, 43 to 48 to the on state and controls the second switch 42 to the off state. This causes the in-vehicle system 1 to enter the tenth state. For example, the control unit 61 determines that an abnormality exists in the power supply from the second low-voltage battery 21 when the control unit 61 determines that the voltage of the second low-voltage battery 21 is equal to or lower than a low-voltage threshold (e.g., 0 V), when the control unit 61 determines that the current supplied to the second low-voltage battery 21 exceeds an overcurrent threshold, or when the control unit 61 determines that the current supplied to the second low-voltage battery 21 is equal to or lower than a low-current threshold (e.g., 0 A).

[0063] For example, if the voltage or current of the first branch path 34A becomes abnormal in the first state, the in-vehicle system 1 enters an eleventh state shown in FIG. 12 . In the eleventh state, power is supplied from the voltage conversion unit 3, the first low-voltage battery 11, and the second low-voltage battery 21 to the first important load 14, the second general load 23, and the second important load 24. For example, if the control unit 61 determines that the voltage or current of the first branch path 34A is abnormal, the control unit 61 controls the switches 41 to 44 and 46 to 48 to the on state and controls the fifth switch 45 to the off state. This causes the in-vehicle system 1 to enter the eleventh state. For example, if the control unit 61 determines that the voltage of the first branch path 34A is equal to or lower than a low-voltage threshold (e.g., 0 V), the control unit 61 determines that the voltage of the first branch path 34A is abnormal. The control unit 61 determines that the current in the first branch path 34A is abnormal, for example, when the current flowing in the first branch path 34A exceeds an overcurrent threshold or when the current flowing in the first branch path 34A is equal to or less than a low current threshold (for example, 0 A).

[0064] For example, if the voltage or current of the second branch path 34B becomes abnormal in the first state, the in-vehicle system 1 enters a twelfth state shown in FIG. 13 . The twelfth state is a state in which power is supplied from the voltage conversion unit 3, the first low-voltage battery 11, and the second low-voltage battery 21 to the first general load 13, the second general load 23, and the second important load 24. For example, if the control unit 61 determines that the voltage or current of the second branch path 34B is abnormal, the control unit 61 controls the switches 41 to 45 and 47 to 48 to the ON state and controls the sixth switch 46 to the OFF state. This causes the in-vehicle system 1 to enter the twelfth state. For example, if the control unit 61 determines that the voltage of the second branch path 34B is equal to or lower than a low-voltage threshold (e.g., 0 V), the control unit 61 determines that the voltage of the second branch path 34B is abnormal. The control unit 61 determines that the current in the second branch path 34B is abnormal, for example, when the current flowing in the second branch path 34B exceeds an overcurrent threshold or when the current flowing in the second branch path 34B is equal to or less than a low current threshold (for example, 0 A).

[0065] For example, if the voltage or current of the third branch path 37A becomes abnormal in the first state, the in-vehicle system 1 enters a thirteenth state shown in FIG. 14 . The thirteenth state is a state in which power is supplied from the voltage conversion unit 3, the first low-voltage battery 11, and the second low-voltage battery 21 to the first general load 13, the first important load 14, and the second important load 24. For example, if the control unit 61 determines that the voltage or current of the third branch path 37A is abnormal, the control unit 61 controls the switches 41 to 46, 48 to the ON state and controls the seventh switch 47 to the OFF state. This causes the in-vehicle system 1 to enter the thirteenth state. For example, if the control unit 61 determines that the voltage of the third branch path 37A is equal to or lower than a low-voltage threshold (e.g., 0 V), the control unit 61 determines that the voltage of the third branch path 37A is abnormal. The control unit 61 determines that the current in the third branch path 37A is abnormal, for example, when the current flowing in the third branch path 37A exceeds an overcurrent threshold or when the current flowing in the third branch path 37A is equal to or less than a low current threshold (for example, 0 A).

[0066] For example, if the voltage or current of the fourth branch path 37B becomes abnormal while the in-vehicle system 1 is in the first state, the in-vehicle system 1 enters a fourteenth state shown in FIG. 15 . The fourteenth state is a state in which power is supplied from the voltage conversion unit 3, the first low-voltage battery 11, and the second low-voltage battery 21 to the first general load 13, the first important load 14, and the second general load 23. For example, if the control unit 61 determines that the voltage or current of the fourth branch path 37B is abnormal, the control unit 61 controls the switches 41 to 47 to the on state and controls the eighth switch unit 48 to the off state. This causes the in-vehicle system 1 to enter the fourteenth state. For example, if the control unit 61 determines that the voltage of the fourth branch path 37B is equal to or lower than a low-voltage threshold (e.g., 0 V), the control unit 61 determines that the voltage of the fourth branch path 37B is abnormal. The control unit 61 determines that the current in the fourth branch path 37B is abnormal, for example, when the current flowing in the fourth branch path 37B exceeds an overcurrent threshold or when the current flowing in the fourth branch path 37B is equal to or less than a low current threshold (for example, 0 A).

[0067] 1-4. Effects of the Vehicle Control Device 40 When power is supplied from the high-voltage power supply 2 to the first conduction path 31 via the voltage conversion unit 3, the vehicle control device 40 controls the first switch unit 41 to an ON state and the second switch unit 42 to an OFF state, thereby charging only the first low-voltage battery 11 of the first low-voltage power supply system. Furthermore, when power is supplied from the high-voltage power supply 2 to the first conduction path 31 via the voltage conversion unit 3, the vehicle control device 40 controls the first switch unit 41 to an OFF state and the second switch unit 42 to an ON state, thereby charging only the second low-voltage battery 21 of the second low-voltage power supply system. In other words, the vehicle control device 40 can selectively charge the first low-voltage battery 11 of the first low-voltage power supply system and the second low-voltage battery 21 of the second low-voltage power supply system.

[0068] The vehicle control device 40 can prevent current from flowing from the first low-voltage battery 11 to the high-voltage power supply 2 or the second low-voltage power supply system by controlling the third switch unit 43 to the off state. In addition, the vehicle control device 40 can prevent current from flowing from the second low-voltage battery 21 to the high-voltage power supply 2 or the first low-voltage power supply system by controlling the fourth switch unit 44 to the off state.

[0069] When an abnormality occurs in the power supply from the voltage conversion unit 3, the on-board control device 40 can operate independently using the first low-voltage power supply system and the second low-voltage power supply system by controlling the third switch unit 43 and the fourth switch unit 44 to the off state.

[0070] At least one of the loads required for the vehicle to travel, the load required for changing the direction of travel of the vehicle, and the load required for stopping the vehicle is provided in each of the first low-voltage power supply system and the second low-voltage power supply system. Therefore, even if an abnormality occurs in either the first low-voltage power supply system or the second low-voltage power supply system, the on-board control device 40 can perform at least one of the operations of traveling, changing the direction of travel, and stopping the vehicle by using the low-voltage power supply system that is not experiencing an abnormality.

[0071] The vehicle control device 40 can selectively cut off the power supply to the first general load 13 , the first important load 14 , the second general load 23 , and the second important load 24 .

[0072] The vehicle control device 40 can be made smaller by accommodating the first switch unit 41, the second switch unit 42, the control unit 61, the first low-voltage battery 11, and the second low-voltage battery 21 all together in a single electrical connection box 62.

[0073] Compared to a configuration in which the processing performed by the control unit 61 is distributed among a plurality of ECUs, the in-vehicle control device 40 can more quickly perform processing in accordance with the results of monitoring the battery voltage.

[0074] <Other Embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or below-described embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or below-described embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiments may be modified as follows.

[0075] In the first embodiment, the control unit 61 is configured by one ECU, but the control unit 61 may be configured by a plurality of ECUs.

[0076] In the first embodiment, the control unit 61 controls the voltage conversion unit 3. However, the control unit 61 may not control the voltage conversion unit 3. In this case, the control unit 61 may determine whether the voltage conversion unit 3 is performing a step-down operation based on information received from an external ECU.

[0077] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0078] REFERENCE SIGNS LIST 1...In-vehicle system 2...High-voltage power supply 3...Voltage conversion unit 11...First low-voltage battery 12...First load 13...First general load 14...First important load 21...Second low-voltage battery 22...Second load 23...Second general load 24...Second important load 31...First conductive path 32...Second conductive path 33...Third conductive path 34...Fourth conductive path 34A...First branch path 34B...Second branch path 35...Fifth conductive path 36...Sixth conductive path 37...Seventh conductive path 37A...Third branch path 37B...Fourth branch path 40...In-vehicle control device 41...First switch unit 42...Second switch unit 43...Third switch unit 44...Fourth switch unit 45...Fifth switch unit 46...Sixth switch unit 47...Seventh switch unit 48...Eighth switch unit 51 to 57: Detection unit 61: Control unit 62: Electrical connection box

Claims

1. An on-board control device included in an on-board system comprising: a high-voltage power supply; a voltage conversion unit that steps down a voltage input from the high-voltage power supply and outputs the stepped-down voltage to a first conductive path; a first low-voltage battery; a first load; a second conductive path having one end connected to the first conductive path; a third conductive path branching from the other end of the second conductive path and connected to the first low-voltage battery; a fourth conductive path branching from the other end of the second conductive path and connected to the first load; a second low-voltage battery; a second load; a fifth conductive path having one end connected to the first conductive path; a sixth conductive path branching from the other end of the fifth conductive path and connected to the second low-voltage battery; and a seventh conductive path branching from the other end of the fifth conductive path and connected to the second load, the on-board control device having: a first switch unit provided in the third conductive path; a second switch unit provided in the sixth conductive path; and a control unit that controls the first switch unit and the second switch unit, an on-board control device, wherein the first switch unit allows current to flow to the first low-voltage battery through itself when in an on state, and blocks current from flowing to the first low-voltage battery through itself when in an off state; the second switch unit allows current to flow to the second low-voltage battery through itself when in an on state, and blocks current from flowing to the second low-voltage battery through itself when in an off state; and the control unit monitors the voltage of the first low-voltage battery and the voltage of the second low-voltage battery, and controls the first switch unit and the second switch unit based on the voltage of the first low-voltage battery and the voltage of the second low-voltage battery.

2. The in-vehicle control device according to claim 1, further comprising: a third switch unit provided in the second conductive path; and a fourth switch unit provided in the fifth conductive path, wherein the third switch unit, when in an on state, allows current to flow from the first low-voltage battery side to the first conductive path side and the fifth conductive path side through itself, and when in an off state, blocks current to flow from the first low-voltage battery side to the first conductive path side and the fifth conductive path side through itself, the fourth switch unit, when in an on state, allows current to flow from the second low-voltage battery side to the first conductive path side and the second conductive path side through itself, and when in an off state, blocks current to flow from the second low-voltage battery side to the first conductive path side and the second conductive path side through itself, and the control unit controls the third switch unit and the fourth switch unit.

3. The vehicle control device according to claim 2, wherein the control unit controls the third switch unit and the fourth switch unit to an off state when an abnormality occurs in the power supply from the voltage conversion unit to the first conductive path.

4. An on-board control device according to claim 2 or claim 3, wherein the first load and the second load each include at least one of a load required for the vehicle to travel, a load required for changing the direction of travel of the vehicle, and a load required for stopping the vehicle.

5. The first load includes a first general load and a first important load that is more important than the first general load; the second load includes a second general load and a second important load that is more important than the second general load; at least one of a load necessary for the vehicle to run, a load necessary for the vehicle to change its direction of travel, and a load necessary for the vehicle to stop is included in each of the first important load and the second important load; the fourth conductive path includes a first branch path connected to the first general load and a second branch path connected to the first important load; the seventh conductive path includes a third branch path connected to the second general load and a fourth branch path connected to the second important load; and further includes a fifth switch unit provided in the first branch path, a sixth switch unit provided in the second branch path, a seventh switch unit provided in the third branch path, and an eighth switch unit provided in the fourth branch path. The in-vehicle control device according to claim 4, wherein the fifth switch unit allows current to flow to the first general load side through itself when in an on state and blocks current flow to the first general load side through itself when in an off state; the sixth switch unit allows current to flow to the first important load side through itself when in an on state and blocks current flow to the first important load side through itself when in an off state; the seventh switch unit allows current to flow to the second general load side through itself when in an on state and blocks current flow to the second general load side through itself when in an off state; the eighth switch unit allows current to flow to the second important load side through itself when in an on state and blocks current flow to the second important load side through itself when in an off state; and the control unit controls the fifth switch unit, the sixth switch unit, the seventh switch unit, and the eighth switch unit.

6. An on-board control device according to any one of claims 1 to 3, comprising: an electrical connection box provided between the voltage conversion unit and the first load and the second load; the first low-voltage battery; and the second low-voltage battery, wherein the electrical connection box is electrically connected to the voltage conversion unit, the first load, and the second load, and the first switch unit, the second switch unit, the control unit, the first low-voltage battery, and the second low-voltage battery are housed within the electrical connection box.

7. The vehicle control device according to any one of claims 1 to 3, wherein the control unit is configured by one ECU.

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