Control device and vehicle

Abstract

A control device according to the present invention is for a vehicle that comprises auxiliary devices, an auxiliary battery provided as a power source for the auxiliary devices, a relay inserted between the auxiliary battery and the auxiliary devices, and a high-voltage battery having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, the control device comprising: a control unit that carries out ON / OFF control of the relay; and a switch unit that has a switch mechanism that can switch between an ON state and an OFF state and outputs a signal to the control unit instructing the relay to turn ON in response to the switch mechanism being switched to the ON state. The control unit executes: a process of determining whether an abnormality that leads to smoke or fire has occurred in the high-voltage battery; and a process of, if it is determined that an abnormality has not occurred, controlling the relay to be turned OFF in response to a determination that a state in which the remaining charge of the auxiliary battery is equal to or less than a first margin threshold that is greater than an over-discharge progression prevention threshold and that the auxiliary battery is in a discharge state has continued for a prescribed amount of time or longer, and if it is determined that an abnormality has occurred, controlling the relay to be turned OFF in response to a determination that the remaining charge of the auxiliary battery is equal to or less than the over-discharge progression prevention threshold.

Description

Control device, vehicle

[0001] This technology relates to a control device in a vehicle equipped with an accessory battery used as a power source for accessories, and to the vehicle, and particularly relates to a technology for performing control related to the interruption of the accessory battery.

[0002] As a substitute for a 12V lead-acid battery for accessories, the use of a lithium-ion battery is being considered. Specifically, in a vehicle as an electric vehicle equipped with a motor for running, an accessory battery using a lithium-ion battery as a power source for accessories is mounted separately from a high-voltage battery used as a power source for the motor.

[0003] Regarding related prior art, Patent Document 1 below can be cited. In Patent Document 1 below, when the voltage of the accessory battery becomes less than a voltage (second predetermined voltage Sb2) at which the control device (HVECU) cannot be started when further discharged, the accessory battery is discharged before the drive battery used as a power source for the running motor. A technology is disclosed.

[0004] Japanese Unexamined Patent Application Publication No. 2023-127603

[0005] Here, when a lithium-ion battery is used as the accessory battery, the behavior during battery charging is different from that when a conventional lead-acid battery is used. In the case of a lithium-ion battery, a control circuit called a BMS (Battery Management System) for protecting the battery cells is mounted. When the battery cells are not charged for some reason and the SOC (State Of Charge) as the remaining battery capacity decreases, a relay function (called SMR: System Main Relay) that self-interrupts power is implemented to prevent the battery from entering an irreversibly non-reusable state due to the progress of over-discharge.

[0006] However, this SMR function results in a loss of power to various on-board ECUs (Electric Control Units) and other auxiliary components. Therefore, even if you want to recharge the auxiliary battery, you cannot start the high-voltage system, and thus you cannot charge the auxiliary battery from the high-voltage battery.

[0007] This technology was developed in view of the above circumstances, and aims to achieve appropriate auxiliary battery shutoff control according to the vehicle's condition when using batteries such as lithium-ion batteries, which have measures in place to prevent over-discharge, as auxiliary batteries.

[0008] A control device according to one embodiment of the present technology is a vehicle comprising: auxiliary equipment; an auxiliary battery provided as a power source for the auxiliary equipment; a relay inserted between the auxiliary battery and the auxiliary equipment; and a high-voltage battery having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, wherein the control device comprises: a control unit that controls the on / off state of the relay; and a switch unit having a switch mechanism that can switch between an on state and an off state, and which outputs a signal to the control unit to instruct the relay to be turned on when the switch mechanism is turned on, and the control unit comprises one or more processors and a storage medium storing a program executed by the one or more processors. The program includes one or more instructions, each instruction causing the one or more processors to perform the following: determine whether or not an abnormality has occurred that could lead to smoke or fire in the high-voltage battery; if it is determined that no abnormality has occurred, control the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below a first margin threshold greater than the over-discharge progression prevention threshold and that the auxiliary battery has been in a discharged state for a predetermined period of time or longer; and if it is determined that an abnormality has occurred, control the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below the over-discharge progression prevention threshold.

[0009] According to this technology, when using a battery such as a lithium-ion battery, which has measures in place to prevent over-discharge, as an auxiliary battery, it is possible to achieve appropriate auxiliary battery shutoff control according to the vehicle's condition.

[0010] This figure shows an example of the schematic internal configuration of a vehicle equipped with a control device as the first embodiment. This figure explains the detailed configuration of the power control system according to the embodiment provided in the vehicle as the first embodiment. This is an explanatory diagram of an example of the configuration of the switch section. This is an explanatory diagram of the over-discharge progression prevention threshold and the first margin threshold. This is a flowchart showing an example of a specific processing procedure for realizing the control method as the first embodiment. This figure shows an example of the configuration of the power control system in a vehicle as the second embodiment. This figure shows an example of the second margin threshold. This is a flowchart showing an example of a specific processing procedure for realizing the control method as the second embodiment. This figure shows an example of the configuration of the power control system in a vehicle as the third embodiment. This is a flowchart of the first process corresponding to the completion of assembly. This is a flowchart of the second process to enable resetting of the first margin threshold. This figure shows an example of the configuration of the power control system in a vehicle as the fourth embodiment. This is a flowchart showing an example of a specific processing procedure for realizing the control method as the fourth embodiment. This is a flowchart showing an example of a specific processing procedure for realizing the control method as an alternative example of the fourth embodiment.

[0011] The embodiments of the present invention will be described below with reference to the attached drawings. The description will proceed in the following order: <1. First Embodiment> <2. Second Embodiment> <3. Third Embodiment> <4. Fourth Embodiment> <5. Modified Examples> <6. Summary of Embodiments>

[0012] <1. First Embodiment> Figure 1 is a diagram showing a schematic internal configuration example of a vehicle 100 equipped with a control device 1 as a first embodiment of the present technology. As shown in the figure, the control device 1 includes a switch unit 20 and an auxiliary battery unit 10. Details of the control device 1 in this embodiment will be explained later.

[0013] The vehicle 100 in this embodiment is configured as a HEV (Hybrid Electric Vehicle) equipped with an engine 2 and an MG (motor generator) 4, and is equipped with a high-voltage battery 5 (driving battery) to supply the driving power to the MG 4. In the HEV vehicle 100, the engine 2 may be used as a drive source for the wheels, or it may be used as a power source to generate power for driving the MG 4 and for charging the high-voltage battery 5.

[0014] In this example, vehicle 100 is assumed to be a four-wheeled vehicle, but the vehicle in the embodiment can be any vehicle with at least two or more wheels.

[0015] In vehicle 100, an inverter 6 is provided for the MG 4. When the MG 4 is powered, the inverter 6 outputs a drive voltage to the MG 4 based on the input voltage from the high-voltage battery 5, and during regeneration, it charges the high-voltage battery 5 using the regenerative power from the MG 4.

[0016] Furthermore, the vehicle 100 is equipped with auxiliary equipment 3. The auxiliary equipment 3 broadly includes various electronic components for operating the engine 2, such as fuel injectors and electronic throttles, as well as various ECUs (Electric Control Units) for controlling various operations of the vehicle 100, such as controlling the engine 2 and MG4, and onboard electronic equipment such as meters, navigation equipment, and audio equipment.

[0017] Furthermore, the vehicle 100 is equipped with an auxiliary battery unit 10 for supplying power to the auxiliary equipment 3. The auxiliary battery unit 10 has an auxiliary battery 11 provided as a power source for the auxiliary equipment 3. In this example, the rated output voltage of the auxiliary battery 11 is set to 12V. However, the rated output voltage of the auxiliary battery 11 may be 24V, for example, and is not limited to 12V. The rated output voltage of the auxiliary battery 11 is set to be lower than the rated output voltage of the high-voltage battery 5 (for example, 400V, for example).

[0018] In vehicle 100, a lithium-ion battery is used for the auxiliary battery 11, rather than a lead-acid battery. Compared to lead-acid batteries, lithium-ion batteries can be made smaller and lighter in terms of battery weight and size, offering advantages in terms of reducing vehicle weight and installation space.

[0019] In the vehicle 100, the auxiliary battery 11 can be charged by the high-voltage battery 5. When the auxiliary battery 11 is charged by the high-voltage battery 5, a DC / DC converter 7 is used. The DC / DC converter 7 has a step-down function and charges the auxiliary battery 11 by stepping down the input voltage from the high-voltage battery 5 (stepping it down to 12V in this example) and outputting it to the auxiliary battery unit 10.

[0020] Furthermore, the vehicle 100 is equipped with a switch unit 20. The switch unit 20 is provided to enable an operation to release the power supply interruption when the power supply from the auxiliary battery 11 to the auxiliary equipment 3 is interrupted in response to the remaining charge of the auxiliary battery 11, specifically the State of Charge (SOC) of the auxiliary battery 11, falling below a predetermined threshold. The switch unit 20 will be explained in more detail later.

[0021] Figure 2 is a diagram illustrating the detailed configuration of the power control system according to the embodiment provided in the vehicle 100. Specifically, Figure 2 shows the auxiliary equipment 3, high-voltage battery 5, DC / DC converter 7, and switch unit 20 shown in Figure 1, as well as an example of the internal configuration of the auxiliary battery unit 10 and various ECUs (onboard ECUs) provided in the vehicle 100. As mentioned above, the onboard ECU constitutes a part of the auxiliary equipment 3, but in Figure 2, for illustrative purposes, the onboard ECU is shown separately from the auxiliary equipment 3.

[0022] As shown in the figure, the vehicle 100 is equipped with an on-board ECU, which includes a power management ECU 41, a communication ECU 42, and other ECUs 43. The power management ECU 41 controls the charging of the auxiliary battery 11 using the high-voltage battery 5. Specifically, the power management ECU 41 determines whether the auxiliary battery 11 can be charged, and if it determines that it can be charged, it turns on the DC / DC converter 7 to charge the auxiliary battery 11 from the high-voltage battery 5. In this example, the determination of whether the auxiliary battery 11 can be charged is made based on the State of Control (SOC) of the auxiliary battery 11 and the State of Control (SOC) of the high-voltage battery 5. Specifically, the power management ECU 41 obtains the SOC of the high-voltage battery 5 and also obtains the SOC of the auxiliary battery 11 from the control unit 13 in the auxiliary battery unit 10 (described later), and determines whether the auxiliary battery 11 can be charged based on these obtained SOCs. The power management ECU 41 may also be an ECU that controls the switching between powering and regenerative braking of the MG4, or controls the motor output during powering.

[0023] The communication ECU 42 is an ECU configured to communicate with an external device, which is an information processing device outside the vehicle. In this example, the communication ECU 42 is configured to communicate with a server device that manages vehicle information, which is the external device mentioned above. In this example, this server device is configured as a cloud server used for a service that provides users with various information about the vehicle 100. For example, a user installs an application to receive the service on a user terminal such as a smartphone owned by the user, and registers necessary information (for example, account information and vehicle identifiers such as the vehicle identification number of the vehicle 100) with the server device. As a result, the user can receive various information about the vehicle 100 through the application. For example, it is possible to receive notifications about inspection dates, view vehicle information such as total mileage and remaining fuel, etc.

[0024] Other ECUs 43 comprehensively refer to the on-board ECUs in the vehicle 100 other than the power management ECU 41 and the communication ECU 42. Examples of other ECUs 43 include, for example, the engine control ECU that controls the engine 2, the driving stability control ECU that performs controls related to improving driving stability such as anti-skid control, the air conditioning ECU that controls the air conditioning, the door ECU that performs controls related to locking and unlocking the doors, and the lighting ECU that controls the on / off of lights such as headlamps and turn signals.

[0025] As shown in the figure, the power management ECU 41, communication ECU 42, and other ECUs 43 are connected via a bus 40, enabling data communication according to a predetermined communication method such as CAN (Controller Area Network).

[0026] The auxiliary battery unit 10, together with the auxiliary battery 11, includes a relay 12 and a control unit 13. The auxiliary battery unit 10 also has terminals including a positive terminal Tp, a negative terminal Tm, a data terminal Td, a switch signal terminal Ts, and a GND (ground) terminal Tg.

[0027] Outside the auxiliary battery unit 10, as shown in the figure, the auxiliary components 3 are inserted between the positive terminal Tp and the negative terminal Tm, which is grounded to GND. Similarly, the DC / DC converter 7 and the high-voltage battery 5 are also inserted between the positive terminal Tp and the negative terminal Tm.

[0028] Within the auxiliary battery unit 10, a series connection circuit between the relay 12 and the auxiliary battery 11 is inserted between the positive terminal Tp and the negative terminal Tm. The relay 12 is configured as an electromagnetic relay, and its on / off switching is controlled by the control unit 13. When the relay 12 is ON, the auxiliary battery 11 and the positive terminal Tp are electrically connected, and power from the auxiliary battery 11 can be supplied to the auxiliary equipment 3. Furthermore, the electrical connection between the auxiliary battery 11 and the positive terminal Tp makes it possible to charge the auxiliary battery 11 with power from the high-voltage battery 5 via the DC / DC converter 7. On the other hand, when the relay 12 is OFF, the auxiliary battery 11 and the positive terminal Tp are electrically disconnected, and power cannot be supplied from the auxiliary battery 11 to the auxiliary equipment 3. Furthermore, charging of the auxiliary battery 11 by the high-voltage battery 5 also becomes impossible.

[0029] The control unit 13 is configured with a microcomputer having, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The CPU performs various processes according to the program stored in the ROM, thereby performing various controls on the auxiliary battery unit 10. Although not shown in the diagram, the control unit 13 is powered by the auxiliary battery 11.

[0030] The control unit 13 is connected to the bus 40 described above via a data terminal Td, and is capable of data communication with various in-vehicle ECUs, specifically the power management ECU 41, communication ECU 42, and other ECUs 43 described above.

[0031] Furthermore, the control unit 13 has a function for monitoring the status of the auxiliary battery 11. For example, it is possible to monitor the output voltage value, output current value, battery temperature, etc. of the auxiliary battery 11, and to calculate SOC and SOH (State of Health).

[0032] Furthermore, the control unit 13 also controls the relay 12 based on the status monitoring results of the auxiliary battery 11. For example, the control unit 13 performs countermeasures when an abnormality occurs in the auxiliary battery 11 that could lead to smoke and fire, such as thermal runaway. Specifically, it determines whether an abnormality that could lead to smoke and fire has occurred in the auxiliary battery 11, and if it determines that such an abnormality has occurred, it controls the relay 12 to turn off. Abnormalities that could lead to smoke and fire include, for example, an overcharge state (a state where charging continues at a high voltage exceeding SOC = 100%), an overcurrent state (a state of high current discharge due to an external short circuit, etc.: for example, 200A or more), a high cell temperature state (a high temperature state where the cell electrolyte boils due to an internal cell short circuit, overcharging, overcurrent, etc.: for example, 100 degrees Celsius or more), a failure of the relay 12, or an abnormal state of components related to the determination of abnormalities that could lead to smoke and fire (for example, a temperature sensor, a current sensor, a microcontroller, etc.). In the following example, we will illustrate how to determine whether or not an abnormality has occurred in the auxiliary battery 11 that could lead to smoke and fire, by determining whether or not the auxiliary battery 11 is in a thermal runaway state. The determination of whether or not the battery is in a thermal runaway state can be made using any known method, and is not limited to any specific method. For example, a determination method based on the temperature detected by a temperature sensor that detects the battery temperature, or a determination method based on the short-circuit detection result of the battery's internal circuitry, can be cited as examples.

[0033] Furthermore, the control unit 13 controls the relay 12 to turn off in response to a decrease in the remaining charge of the auxiliary battery 11, thereby cutting off the power supply from the auxiliary battery 11 to the auxiliary equipment 3. Hereinafter, the control that controls the relay 12 to turn off in response to a decrease in the remaining charge of the auxiliary battery 11, thereby cutting off the power supply from the auxiliary battery 11 to the auxiliary equipment 3, will be referred to as "low charge cutoff control." This embodiment has features regarding the conditions for executing such low charge cutoff control, but the details will be explained later.

[0034] By performing the above-described low-charge shutoff control, when a lithium-ion battery is used as the auxiliary battery 11, it becomes possible to prevent over-discharge of the auxiliary battery 11, thereby preventing the auxiliary battery 11 from becoming irreversibly unusable.

[0035] In this case, the low-charge shutoff control described above causes a loss of power to the auxiliary equipment 3, including various on-board ECUs (Electric Control Units), making it impossible to start the high-voltage system and charge the auxiliary battery 11. In order to recharge and reuse the auxiliary battery 11, it is necessary to either connect a diagnostic tool to the vehicle 100 and send a restart command to the control unit 13 instructing it to turn on the relay 12, or to remove the auxiliary battery 11 from the vehicle 100 and replace it with a new one. This complicates the process of returning the vehicle 100 to a drivable state and leads to increased repair costs.

[0036] Therefore, in this embodiment, a switch unit 20 is provided. The switch unit 20 has a switch mechanism that can be switched between an ON state and an OFF state, and is configured to output a signal to the control unit 13 instructing the relay 12 to turn ON when the switch mechanism is turned ON. By providing such a switch unit 20, even when the power supply to the auxiliary equipment 3 is stopped due to the low charge cut-off control for the protection of the auxiliary battery 11, if the user turns on the switch unit 20, the relay 12 will be forcibly turned ON, and power supply to the auxiliary equipment 3 will become possible. Once power supply to the auxiliary equipment 3 becomes possible, the high-voltage system starts up and the auxiliary battery 11 can be charged by the high-voltage battery 5, and thereafter, power supply from the auxiliary battery 11 to the auxiliary equipment 3 can be continued as usual. In other words, in this case, the only action required to deal with a dead battery is for the user to turn on the switch unit 20. In this way, even when a lithium-ion battery is provided as the auxiliary battery 11, the complexity of the action required to deal with a dead battery is prevented.

[0037] Here, the switch unit 20 can be configured as a physical switch, such as a push-button switch, a knob switch, a slide switch, or a dial switch, which is installed at a predetermined location on the vehicle 100.

[0038] However, if the switch unit 20 is configured with a push-button switch or a knob switch as described above, it may impair the design depending on the installation location, or it may incur manufacturing costs for the switch components. On the other hand, since the switch unit 20 is essentially an emergency switch, it will be used infrequently throughout the lifecycle of the vehicle 100.

[0039] Considering this point, the switch unit 20 can be configured, for example, as shown in Figure 3, as a switch that can be switched between an on state and an off state by inserting or removing a fuse 25 within the fuse box 30 of the vehicle 100. Specifically, the switch unit 20 has a terminal portion 20a (including at least a positive terminal and a negative terminal) formed within the fuse box 30. The on state and off state are switched by inserting or removing a fuse 25 into this terminal portion 20a.

[0040] This prevents the design of the vehicle 100 from being compromised when the switch unit 20 is installed, and also reduces costs because a spare fuse already installed in the vehicle 100 can be used as the fuse 25.

[0041] In Figure 2, the vehicle 100 is provided with a switch signal supply unit 21 for supplying a switch signal to the control unit 13 that indicates the ON or OFF state of the switch mechanism in the switch unit 20. As shown in the figure, one terminal of the switch unit 20 is connected to the control unit 13 via the switch signal terminal Ts. This line connecting one terminal of the switch unit 20 to the control unit 13 via the switch signal terminal Ts is referred to as the positive side line of the switch signal. The other terminal of the switch unit 20 is connected to the control unit 13 via the GND terminal Tg. This line connecting the other terminal of the switch unit 20 to the control unit 13 via the GND terminal Tg is referred to as the negative side line of the switch signal.

[0042] In this example, the control unit 13 determines whether the switch unit 20 is turned on by determining whether the switch signal has changed from an off level to an on level. This makes it possible to isolate the case where the switch unit 20 is stuck in the on state, thereby improving the accuracy of the on / off determination of the switch unit 20. In particular, it is possible to prevent the relay 12 from also becoming stuck in the on state when the switch unit 20 is stuck in the on state, and to prevent power from being mistakenly supplied from the auxiliary battery 11 to the auxiliary equipment 3 under low charge cutoff control.

[0043] Furthermore, in this example, the switch signal supply unit 21 is configured to supply a signal with a predetermined voltage value less than the output voltage of the auxiliary battery 11 to the control unit 13 when the switch unit 20 is turned on. Specifically, as shown in the figure, the switch signal supply unit 21 in this example includes a resistor Ru as a pull-up resistor connected to the positive terminal line of the switch signal and a resistor Rd as a pull-down resistor connected to the negative terminal line of the switch signal. This allows the control unit 13 to be supplied with a signal with a predetermined voltage value less than the output voltage of the auxiliary battery 11 when the switch unit 20 is turned on. Although not shown in the figure, a 12V voltage powered by the auxiliary battery 11 is connected to the resistor Ru as the pull-up resistor.

[0044] Also, in this example, in response to the configuration of the switch signal supply unit 21 as described above, the control unit 13 determines whether the switch unit 20 is turned on or not based on the presence or absence of signal supply by the above-described predetermined voltage value. For example, if the design value of the above-described predetermined voltage value is 5V, the control unit 13 determines whether the voltage value of the supplied switch signal is 5V. In this case, as the determination, it is conceivable to define a voltage range that can be regarded as a predetermined voltage value such as 5V, and perform the determination as to whether the voltage value of the supplied switch signal is within the voltage range. Specifically, if the design value of the predetermined voltage value = 5V, for example, 4V and 6V are defined as the threshold values of the voltage range, and it is determined whether the voltage value of the supplied switch signal is within the range of 4V to 6V.

[0045] By adopting the configuration of the switch signal supply unit 21 and the method for determining the on state of the switch unit 20 as described above, it is possible to prevent the switch unit 20 from being erroneously determined to be in an on state when the supply line of the switch signal is short-circuited to GND. That is, it is possible to prevent the relay 12 from being stuck on during a GND short circuit, and it is possible to prevent power from being erroneously supplied from the auxiliary battery 11 to the auxiliary devices 3 under the cut-off control when the remaining amount decreases.

[0046] As shown in FIG. 2, the control device 1 in the present embodiment includes an auxiliary battery unit 10, a switch unit 20, a switch signal supply unit 21, a power management ECU 41, a communication ECU 42, and other ECUs 43.

[0047] Here, in the control device 1 of the present embodiment, the control unit 13 performs the cut-off control when the remaining amount decreases in consideration of requirements other than the remaining amount of the auxiliary battery 11. Specifically, the control unit 13 performs the cut-off control when the remaining amount decreases in consideration of the viewpoint of whether the discharge state of the auxiliary battery 11 has elapsed for a predetermined time or more.

[0048] More specifically, when the control unit 13 determines that the remaining amount of the auxiliary battery 11 is equal to or less than the over-discharge prevention threshold, it performs a process of controlling the relay 12 to turn off. When the control unit 13 determines that the remaining amount of the auxiliary battery 11 is greater than the over-discharge prevention threshold and equal to or less than the first margin threshold, and the state where the auxiliary battery is in a discharging state has continued for a predetermined time or more, it performs a process of controlling the relay 12 to turn off. Here, as the above-mentioned predetermined time, it is conceivable to set it to a time of about 20 seconds to 1 minute, for example. More specifically, the above-mentioned predetermined time may be set to about 30 seconds, for example.

[0049] FIG. 4 is an explanatory diagram of the over-discharge prevention threshold and the first margin threshold. For confirmation, it should be noted that these over-discharge prevention threshold and first margin threshold are defined as thresholds for the SOC (remaining amount) of the auxiliary battery 11.

[0050] The over-discharge prevention threshold is a threshold for preventing the progress of over-discharge. As is well known, over-discharge means a state where, starting from a state where the SOC is 0%, further energy is extracted by discharging. If the state of over-discharge continues in a lithium-ion battery, the copper foil used for the negative electrode of the battery will dissolve, and the battery will irreversibly become unusable, such as falling into a state where it cannot be reused. The over-discharge prevention threshold is defined to prevent such a state of being unable to be reused. Specifically, the over-discharge prevention threshold is set to 0%.

[0051] As shown in the figure, the region where the SOC is less than 0% is called the over-discharge region. Also, the region where the SOC exceeds 100% is called the overcharge region. In the overcharge region, as the positive electrode of the battery releases more lithium ions than the allowable capacity, the state inside the battery becomes unstable, which promotes the progress of deterioration.

[0052] The first margin threshold is a threshold set to a value greater than the over-discharge prevention threshold. For example, in this example, the first margin threshold is set to 20%, which is +20% with respect to the over-discharge prevention threshold. Note that the above-mentioned +20% is merely an example as the offset value of the first margin threshold with respect to the over-discharge prevention threshold, and it is needless to say that other values can be adopted.

[0053] In this embodiment, as described above, the system performs two processes: turning off the relay 12 when it is determined that the remaining charge of the auxiliary battery 11 is below the over-discharge prevention threshold, and turning off the relay when it is determined that the remaining charge of the auxiliary battery 11 is below the first margin threshold, which is greater than the over-discharge prevention threshold, and that the auxiliary battery 11 has been in a discharged state for a predetermined period of time or longer. If the auxiliary battery 11 has been in a discharged state for a predetermined period of time (approximately 20 seconds to 1 minute in this example) or longer, it can be inferred that some abnormality has occurred in the charging system of the auxiliary battery 11, such as the high-voltage battery 5 being depleted, making it impossible to charge the auxiliary battery 11. In other words, with the above processing, when the auxiliary battery 11 falls below the first margin threshold, and it is impossible to charge the auxiliary battery 11 from the high-voltage battery 5, the relay 12 is turned off. The relay 12 is turned off when the remaining charge of the auxiliary battery 11 falls below a first margin threshold, which is greater than the over-discharge prevention threshold. Therefore, the relay 12 is turned off when there is still some margin remaining in the auxiliary battery 11. In this case, if the self-discharge is only a few days' worth, the high-voltage system can be started by forcibly turning on the relay 12 by operating the switch unit 20, making the auxiliary battery 11 rechargeable by the high-voltage battery 5. Therefore, if the reason the auxiliary battery 11 cannot be charged is the depletion of the high-voltage battery 5, the high-voltage battery 5 can be charged after the high-voltage system is started, making the vehicle 100 drivable. At this time, there is no need to replace the auxiliary battery 11, and the user does not have to bear the burden of a large replacement cost. Furthermore, the workload of returning the vehicle to a normally drivable state is reduced, preventing deterioration of maintainability.Furthermore, if the reason the auxiliary battery 11 cannot be charged is a failure in the power supply system from the high-voltage battery 5 to the auxiliary battery 11, such as a failure of the DC / DC converter 7, the high-voltage system can be activated by forcibly turning on the relay 12 by operating the switch unit 20 as described above. This allows the vehicle 100 to be brought to a vehicle maintenance facility such as a dealer after the high-voltage battery has been charged, making it possible to repair the faulty part and return the auxiliary battery 11 to a state where it can be charged by the high-voltage battery 5. In this case, there is no need to replace the auxiliary battery 11, so the user does not have to bear a large replacement cost, and the workload in returning the vehicle 100 to a state where it can be driven normally is also reduced, thus preventing deterioration of maintainability.

[0054] On the other hand, in this embodiment, regardless of whether the discharge state of the auxiliary battery 11 continues for a predetermined time or longer, if the remaining charge of the auxiliary battery 11 falls below the over-discharge progression prevention threshold, control is performed to turn off the relay 12. In other words, if it is presumed that there is no abnormality in the charging system of the auxiliary battery 11, the over-discharge progression prevention control is performed as in the conventional method.

[0055] Furthermore, in this embodiment, the control unit 13 executes a process to send predetermined notification information via the communication ECU 42 to an external device (as described above, a server device that manages vehicle information in this example) when it is predicted that the remaining charge of the auxiliary battery 11 will fall below the first margin threshold and the relay 12 will be turned off. Specifically, after the control unit 13 determines that the remaining charge of the auxiliary battery 11 has fallen below the first margin threshold, it instructs the communication ECU 42 to send predetermined notification information to the external device at the timing before controlling the relay 12 to turn off.

[0056] This makes it possible to notify a user terminal, such as a smartphone, via an external device that the auxiliary battery 11's remaining charge has fallen below the first margin threshold and the relay 12 has been turned off. Therefore, it is possible to make the user aware that the auxiliary battery 11 has run out of power, and to ensure that corrective action is taken before the auxiliary battery 11 runs out of power, that is, while the high-voltage system is still in a state where it can be started. Notifying the user terminal is preferable because it allows notification to be made even when the user is away from the vehicle 100.

[0057] Furthermore, the control unit 13 in this embodiment performs a process to notify the on-board ECU when it is predicted that the relay 12 will be turned off. Specifically, in this example, the control unit 13 determines that the remaining charge of the auxiliary battery 11 has fallen below the first margin threshold, and before controlling the relay 12 to turn off, it notifies each on-board ECU in the vehicle 100, specifically the power management ECU 41, communication ECU 42, and other ECUs 43 mentioned above.

[0058] In this embodiment, the in-vehicle ECU that receives the notification performs a process to write the RAM's held values ​​to the non-volatile memory in response to the notification.

[0059] This makes it possible to save the RAM's retained values ​​to non-volatile memory before the vehicle's ECU loses power in response to the relay 12 being turned off. Therefore, it is possible to prevent the loss of various learned values ​​and necessary information such as DCT (Diagnostic Trouble Code) of the vehicle's ECU due to the relay 12 being turned off. For example, it is possible to prevent malfunctions such as learning being reset or faults being overlooked.

[0060] It should be noted that the case in which the relay 12 is predicted to be turned off is not limited to the case in which the remaining charge of the auxiliary battery 11 is determined to be below the first margin threshold, as described above. For example, it is conceivable that the case in which the relay 12 is predicted to be turned off may be determined as when the remaining charge of the auxiliary battery 11 falls below a threshold greater than the first margin threshold.

[0061] Furthermore, while the above example shows that notification to save the RAM's retained value to non-volatile memory is given only when relay 12 is turned off based on the first margin threshold, it is also conceivable that this notification may be given when relay 12 is turned off based on the over-discharge prevention threshold (when it is predicted that relay 12 will be turned off based on the over-discharge prevention threshold). In this case, the prediction of turning off relay 12 may be made by determining whether the remaining charge of the auxiliary battery 11 has fallen below the over-discharge prevention threshold, or by determining whether it has fallen below a threshold greater than the over-discharge prevention threshold.

[0062] Referring to the flowchart in Figure 5, a specific example of a processing procedure for realizing the control method as the first embodiment described above will be explained. Note that the processing shown in Figure 5 is executed by the CPU of the control unit 13 based on a program stored in a memory such as ROM of the control unit 13. The processing in Figure 5 is executed when the relay 12 is in the ON state.

[0063] First, in step S101, the control unit 13 determines whether the processing termination condition has been met. That is, it determines whether a predetermined condition has been met, such as when a signal instructing the termination of processing is input, which indicates that the series of processes shown in Figure 5 should be terminated. It should be noted that the series of processes shown in Figure 5 may also be terminated in response to the control of turning off the relay 12 in steps S104 and S108, which will be explained later.

[0064] If the control unit 13 determines in step S101 that the processing termination condition has not been met, it proceeds to step S102 and determines whether or not the auxiliary battery 11 is in a thermal runaway state. For example, it determines whether or not the auxiliary battery 11 is in a thermal runaway state based on the temperature of the auxiliary battery 11, etc.

[0065] If the control unit 13 determines in step S102 that the auxiliary battery 11 is in a thermal runaway state, it proceeds to step S109, controls the relay 12 to turn off, and returns to step S101. This realizes the thermal runaway countermeasures for the auxiliary battery 11 described above.

[0066] On the other hand, if in step S102 the control unit 13 determines that the auxiliary battery 11 is not in a thermal runaway state, the control unit 13 proceeds to step S103 and determines whether the remaining charge of the auxiliary battery 11 is below the first margin threshold and whether the auxiliary battery 11 is in a discharged state.

[0067] In step S103, if it is determined that the remaining charge of the auxiliary battery 11 is below the first margin threshold and that the auxiliary battery is in a discharged state, the control unit 13 proceeds to step S104 to determine whether the above state has continued for a predetermined time or longer. That is, it determines whether the state determined in step S103, "the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 is in a discharged state," has continued for a predetermined time or longer.

[0068] In step S104, if the control unit 13 determines that the condition "the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 is in a discharged state" has continued for a predetermined time or longer, the control unit 13 proceeds to step S107 and notifies the in-vehicle ECUs. Specifically, it notifies each in-vehicle ECU to save the RAM's retained values ​​to non-volatile memory. This enables each in-vehicle ECU to reliably save the RAM's retained values ​​to non-volatile memory before power is lost due to the relay 12 being turned off.

[0069] In step S108, following step S107, the control unit 13 performs a process to cause the communication ECU 42 to transmit predetermined notification information to an external device. This makes it possible to notify a user terminal such as a smartphone via the external device that the remaining charge of the auxiliary battery 11 has fallen below the first margin threshold and the relay 12 has been turned off.

[0070] Note that the order in which the processes in step S107 and step S108 are performed may be reversed.

[0071] In step S109, following step S108, the control unit 13 controls the relay 12 to turn off. If a positive result is obtained in the preceding step S104 and the process in step S109 is executed, and it is estimated that the auxiliary battery 11 is in a state where it cannot be charged, the relay 12 is turned off in accordance with the fact that the remaining charge of the auxiliary battery 11 has fallen below the first margin threshold.

[0072] The control unit 13 returns to step S101 in response to the fact that it controlled the relay 12 to be turned off in step S109.

[0073] On the other hand, in the case where it is determined in step S103 that the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 is not in a discharged state, and in the case where it is determined in step S104 that the condition "the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 is in a discharged state" has not continued for a predetermined time or longer, the control unit 13 proceeds to step S105.

[0074] In step S105, the control unit 13 determines whether the remaining charge of the auxiliary battery 11 is below the over-discharge prevention threshold. If, in step S105, it is determined that the remaining charge of the auxiliary battery 11 is not below the over-discharge prevention threshold, the control unit 13 proceeds to step S106 to turn on the relay 12 and returns to step S101.

[0075] If, as a result of the processing in steps S102 to S106, the auxiliary battery 11 is not in a thermal runaway state, nor is it the case that "the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 is in a discharge state," nor has the state of "the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 is in a discharge state" continued for a predetermined time or longer, and furthermore, the remaining charge of the auxiliary battery 11 is not below the over-discharge prevention threshold, then the relay 12 is kept in the ON state.

[0076] In step S105, if the control unit 13 determines that the remaining charge of the auxiliary battery 11 is below the over-discharge prevention threshold, it proceeds to step S109 to control the relay 12 to turn it off and returns to step S101.

[0077] If the control unit 13 determines in step S101 that the processing termination condition has been met, it completes the series of processes shown in Figure 5.

[0078] <2. Second Embodiment> A second embodiment of this technology will be described with reference to Figures 6 to 8. In the second embodiment, a second margin threshold is used as the threshold value related to the remaining charge of the auxiliary battery 11.

[0079] Figure 6 shows an example of the configuration of the power control system in vehicle 100A as a second embodiment. In the following description, parts that are the same as those already described will be denoted by the same reference numerals and their description will be omitted.

[0080] The vehicle 100A of the second embodiment differs from the vehicle 100 of the first embodiment (see Figure 2) in that it is equipped with a control device 1A instead of the control device 1. The control device 1A differs from the control device 1 in that it is equipped with a display control ECU 44 as another ECU 43. Furthermore, the vehicle 100A of the second embodiment differs from the vehicle 100 of the first embodiment in that it is equipped with a display unit 50. The display unit 50 has a display panel capable of displaying images, such as a liquid crystal panel or an organic EL (Electro-Luminescence) panel, and is installed in the passenger compartment to display various information to the occupants. Possible forms of the display unit 50 include, for example, a form arranged in the instrument panel, such as within the meter panel, or a form of HUD (Head Up Display). The display control ECU 44 is an ECU that controls the display of the display unit 50.

[0081] In the control device 1A of the second embodiment, the control unit 13 determines whether the remaining charge of the auxiliary battery 11 has fallen below a second margin threshold, which is greater than the first margin threshold. If it determines that the remaining charge of the auxiliary battery has fallen below the second margin threshold, it performs a process to display information on the display unit 50 indicating a remaining charge that is less than the actual remaining charge, as information related to the remaining charge of the auxiliary battery 11.

[0082] Figure 7 shows an example of a second margin threshold. The second margin threshold should be set to a value that is greater than the first margin threshold and close to the first margin threshold. As an example, in this example, the second margin threshold is set to 25%, which is 5% higher than the first margin threshold, as shown in the figure.

[0083] When the control unit 13 determines that the remaining charge of the auxiliary battery 11 has fallen below the second margin threshold, it transmits to the display control ECU 44 a value obtained by subtracting a predetermined offset value from the actual remaining charge of the auxiliary battery 11 (for example, the remaining charge of the auxiliary battery 11 used for the determination), and instructs the display unit 50 to display this value as the remaining charge information for the auxiliary battery 11. Here, the offset value can be set such that, for example, the displayed remaining charge on the display unit 50 becomes 0% when the actual remaining charge reaches the first margin threshold, in order to encourage the user to take action earlier. Specifically, in this example, since the first margin threshold = 20%, the offset value is set to 20%. In this case, when the remaining charge of the auxiliary battery 11 falls below the second margin threshold, the displayed remaining charge on the display unit 50 will be 5%.

[0084] As described above, by displaying information regarding the remaining charge of the auxiliary battery 11 on the display unit 50 when the remaining charge of the auxiliary battery 11 falls below the second margin threshold, which is greater than the first margin threshold, it becomes possible to make the driver aware that the remaining charge of the auxiliary battery 11 is low before the relay 12 is actually turned off, that is, before the power supply to the auxiliary equipment 3 is forcibly stopped. This helps prevent the driver from becoming anxious or losing composure and making a mistake. At this time, by displaying information indicating a remaining charge lower than the actual remaining charge of the auxiliary battery 11, it is possible to encourage the driver to take early action, and it becomes less likely that the power supply to the auxiliary equipment 3 will be forcibly stopped due to the relay being turned off.

[0085] Furthermore, the remaining charge information of the auxiliary battery 11 could also be displayed as part of the warning information that the relay 12 will be turned off and power supply to the auxiliary equipment 3 will be cut off. For example, the display could read, "The auxiliary battery charge is now 5%. Power supply to the auxiliary equipment will be cut off."

[0086] Figure 8 is a flowchart showing a specific example of a processing procedure for realizing the control method as the second embodiment described above. In the following explanation, processes that are the same as those already described will be given the same step number and their explanation will be omitted.

[0087] The difference from the process shown in Figure 5 is that if step S102 determines that the auxiliary battery 11 is not in a thermal runaway state, the process in step S201 is executed. In step S201, the control unit 13 determines whether the remaining charge of the auxiliary battery 11 is below the second margin threshold. If the remaining charge of the auxiliary battery 11 is not below the second margin threshold, the control unit 13 returns to step S101.

[0088] On the other hand, if the remaining charge of the auxiliary battery 11 is below the second margin threshold, the control unit 13 proceeds to step S202 and performs a process to display information on the display unit 50 indicating a remaining charge less than the actual remaining charge. That is, it transmits a value obtained by subtracting a predetermined offset value from the actual remaining charge of the auxiliary battery 11 to the display control ECU 44 and instructs it to display this value on the display unit 50 as the remaining charge information for the auxiliary battery 11.

[0089] In this case, the control unit 13 proceeds to step S103 in accordance with the execution of step S202. That is, if the remaining charge of the auxiliary battery 11 falls below the second margin threshold and then further falls below the first margin threshold, control to turn off the relay 12 is executed according to the conditions of steps S103 and S104, thereby cutting off the power supply to the auxiliary equipment 3.

[0090] In the example shown in Figure 8, steps S107 and S108 are executed in accordance with the case where the remaining charge of the auxiliary battery 11 falls below the first margin threshold, similar to the case of the first embodiment. However, in the second embodiment, these processes are not mandatory.

[0091] <3. Third Embodiment> Figure 3 shows an example of the configuration of the power control system in vehicle 100B as a third embodiment. In the third embodiment, the first margin threshold used by the control unit 13 can be set from the on-board ECU side.

[0092] As shown in the figure, the vehicle 100B of the third embodiment differs from the vehicle 100A of the second embodiment in that it is equipped with a control device 1B instead of the control device 1A. The control device 1B differs from the control device 1A in that the first margin threshold is stored in the power management ECU 41. Specifically, the first margin threshold is stored in the ROM of the power management ECU 41.

[0093] In the control device 1B of the third embodiment, the first margin threshold stored in the on-board ECU is set in the control unit 13 of the auxiliary battery unit 10. Specifically, this setting of the first margin threshold to the control unit 13 is performed when the assembly of the vehicle 100B is completed.

[0094] As described above, by adopting the method of setting the first margin threshold stored on the in-vehicle ECU side to the control unit 13, it becomes possible to eliminate the need for the supplier of the auxiliary battery unit 10 to manage the first margin threshold for each manufacturer and vehicle model, even when the setting value of the first margin threshold differs depending on the vehicle manufacturer and vehicle model. Therefore, the burden on the supplier can be reduced.

[0095] Furthermore, in this embodiment, after the assembly is complete and the settings are made, a check is performed to determine if the first margin threshold stored in the power management ECU 41 matches the first margin threshold stored in the control unit 13. If there is a mismatch, the first margin threshold is reset for the control unit 13. If there is a mismatch between the first margin threshold stored in the power management ECU 41 and the first margin threshold stored in the control unit 13, a notification process is performed for the user.

[0096] Examples of specific processing procedures will be explained with reference to the flowcharts in Figures 10 and 11. Figure 10 is a flowchart of the first processing corresponding to the completion of assembly. In Figures 10 and 11, the processing shown as power management ECU is performed by the CPU of the power management ECU 41, and the processing shown as control unit is performed by the CPU of the control unit 13.

[0097] First, in step S301, the power management ECU 41 determines whether it is the initial power-on. If it is the initial power-on, in step S302, it determines whether it is the initial communication establishment. That is, it establishes communication with the control unit 13 and determines whether this is the initial communication establishment. If it is determined in step S201 that it is not the initial power-on, the power management ECU 41 completes the series of processes shown in Figure 10. Similarly, if it is determined in step S202 that it is not the initial communication establishment, the power management ECU 41 also completes the series of processes shown in Figure 10.

[0098] In step S202, if it is determined that the initial communication has been established, the power management ECU 41 proceeds to step S303 and requests the transmission of the first margin threshold. That is, it requests the control unit 13 to transmit the first margin threshold stored in the control unit 13's ROM. Here, the ROM of the control unit 13 is assumed to be a rewritable ROM, specifically an EEPROM (EEP: Electrically Erasable Programmable).

[0099] In response to the request in step S303, the control unit 13 transmits the first margin threshold stored in the ROM to the power management ECU 41.

[0100] When the power management ECU 41 receives the first margin threshold from the control unit 13, it determines in step S304 whether the thresholds match. That is, it determines whether the received first margin threshold matches the first margin threshold stored in its own ROM. If the two thresholds match, the power management ECU 41 completes the series of processes shown in Figure 10.

[0101] On the other hand, if the two thresholds do not match, the power management ECU 41 proceeds to step S305 and issues a rewrite instruction. That is, it instructs the control unit 13 to rewrite the first margin threshold stored in the control unit 13's ROM with the first margin threshold stored in its own ROM. Then, in the following step S306, the power management ECU 41 performs a process to transmit the first margin threshold to the control unit 13. The power management ECU 41 completes the series of processes shown in Figure 10 in accordance with the execution of the transmission process in step S306.

[0102] The control unit 13 determines in step S402 whether or not there is a rewrite instruction in step S305. If there is no rewrite instruction, it completes the series of processes shown in Figure 10. If there is a rewrite instruction, it proceeds to step S403 and executes the rewrite process of the first margin threshold. That is, it performs a process to rewrite the first margin threshold stored in its own ROM with the first margin threshold transmitted in step S306. This rewrite process can be rephrased as the process by which the control unit 13 stores the first margin threshold received from the power management ECU 41.

[0103] The control unit 13 completes the series of processes shown in Figure 10 in accordance with the execution of the rewriting process in step S403.

[0104] Figure 11 is a flowchart of the second process for enabling the resetting of the first margin threshold. This second process shown in Figure 11 is executed when predetermined conditions are met, such as each time the vehicle 100B is started in response to a startup operation such as pressing the start button. It is also conceivable that the process shown in Figure 11 be executed in response to temporal conditions, such as every month or every six months.

[0105] As shown in the figure, in step S303, the power management ECU 41 requests the control unit 13 to transmit the first margin threshold.

[0106] In response to the request in step S303, the control unit 13 transmits the first margin threshold stored in the ROM to the power management ECU 41.

[0107] When the power management ECU 41 receives the first margin threshold from the control unit 13, it determines in step S304 whether the thresholds match. If both thresholds match, the power management ECU 41 completes the series of processes shown in Figure 11.

[0108] On the other hand, if the two thresholds do not match, the power management ECU 41 proceeds to step S310 and performs notification processing. This notification processing is to inform the user that the first margin threshold stored in the control unit 13 does not match the first margin threshold stored in the power management ECU 41. As part of this notification processing, the power management ECU 41 in this example performs the process of displaying message information indicating that the two thresholds do not match on the display unit 50 via the display control ECU 44.

[0109] In response to the notification process in step S310, the power management ECU 41 proceeds to step S305, issues a rewrite instruction to the control unit 13, and then in step S306 transmits the first margin threshold to the control unit 13.

[0110] In this case as well, the control unit 13 determines in step S402 whether or not there is a rewrite instruction in step S305. If there is no rewrite instruction, it completes the series of processes shown in Figure 11. If there is a rewrite instruction, it proceeds to step S403 and executes the rewrite process of the first margin threshold.

[0111] In the third embodiment, the second margin threshold can also be configured to be set from the in-vehicle ECU, similar to the first margin threshold.

[0112] <4. Fourth Embodiment> The fourth embodiment provides a response to the event of an abnormality in the high-voltage battery 5 that leads to smoke emission and fire. Figure 12 is a diagram showing an example of the configuration of the power control system in vehicle 100C as the fourth embodiment. As shown in the figure, vehicle 100C of the fourth embodiment differs from vehicle 100A of the second embodiment in that it is equipped with control device 1C instead of control device 1A. Control device 1C differs from control device 1A in that it is equipped with a power management ECU 41 instead of power management ECU 41, and an auxiliary battery unit 10C is provided instead of auxiliary battery unit 10.

[0113] The power management ECU 41C has a function to detect abnormalities in the high-voltage battery 5 that could lead to smoke and fire, and a function to shut off the high-voltage battery 5. Specifically, the power management ECU 41C determines whether or not an abnormality has occurred in the high-voltage battery 5 that could lead to smoke and fire, based on the temperature of the high-voltage battery 5, etc. Here, abnormalities that could lead to smoke and fire in the high-voltage battery 5 include overcharging, overcurrent, high cell temperature, and abnormal conditions of components related to the determination of abnormalities that could lead to smoke and fire, similar to the abnormalities that could lead to smoke and fire in the auxiliary battery 11 described above. As an example, below we will illustrate the case in which the determination of whether or not an abnormality has occurred in the high-voltage battery 5 that could lead to smoke and fire is made by determining whether or not the high-voltage battery 5 is in a thermal runaway state. Note that the method for determining whether or not the battery is in a thermal runaway state has already been explained, so we will avoid repeating the explanation. The power management ECU 41C determines whether an abnormality has occurred in the high-voltage battery 5 that could lead to smoke and fire (in this example, whether or not it is in a thermal runaway state). If it determines that an abnormality has occurred in the high-voltage battery 5 that could lead to smoke and fire, it controls the high-voltage relay (not shown) (the cutoff switch for the high-voltage battery 5) to turn off. This allows the electrical connection between the high-voltage battery 5 and other circuits (such as the inverter 6 and DC / DC converter 7) to be cut off when an abnormality occurs in the high-voltage battery 5 that could lead to smoke and fire.

[0114] The auxiliary battery unit 10C differs from the auxiliary battery unit 10 in that it has a control unit 13C instead of the control unit 13. The control unit 13C differs from the control unit 13 in that it performs countermeasures when an abnormality occurs in the high-voltage battery 5 that leads to smoke and fire (in this example, when it enters a thermal runaway state).

[0115] Specifically, the control unit 13C performs the following two processes: First, it determines whether or not an abnormality (thermal runaway state in this example) has occurred in the high-voltage battery 5 that would lead to smoke and fire. Second, if it determines that no abnormality has occurred in the high-voltage battery 5 that would lead to smoke and fire, it controls the relay 12 to turn off in accordance with the determination that the remaining charge of the auxiliary battery 11 is below the first margin threshold and the auxiliary battery 11 has been in a discharge state for a predetermined period of time or longer. If it determines that an abnormality has occurred in the high-voltage battery 5 that would lead to smoke and fire, it controls the relay 12 to turn off in accordance with the determination that the remaining charge of the auxiliary battery 11 is below the over-discharge prevention threshold.

[0116] In this case, if an abnormality occurs in the high-voltage battery 5 that leads to smoke and fire, the high-voltage battery 5 will be shut off, and power supply from the DC / DC converter 7 to the auxiliary equipment 3 will become impossible. As a result, power will be supplied to the auxiliary equipment 3 solely by the auxiliary battery 11. If the relay 12 is turned off based on the first margin threshold described in the first embodiment under these circumstances, even if there is sufficient remaining charge in the auxiliary battery 11, the cooling system of the high-voltage battery 5, electric power steering, electronically controlled brakes, and other controls related to driving will stop, which may make it difficult to ensure the safety of the occupants.

[0117] Therefore, in the fourth embodiment, the system determines whether or not an abnormality has occurred in the high-voltage battery 5 that could lead to smoke and fire. If it is determined that such an abnormality has occurred, instead of turning off the relay 12 based on the first margin threshold, the system turns off the relay 12 in accordance with the determination that the remaining charge of the auxiliary battery 11 is below the over-discharge prevention threshold. This ensures that even if an abnormality occurs in the high-voltage battery 5 that could lead to smoke and fire, the control related to driving can be continued as much as possible, thereby improving safety.

[0118] Figure 13 is a flowchart showing an example of a specific processing procedure that the control unit 13C should execute to realize the control method as the fourth embodiment described above. The difference from the processing in Figure 5 is that if it is determined in step S102 that the auxiliary battery 11 is not in a thermal runaway state, the processing in step S501 is executed. In step S501, the control unit 13C determines whether or not the high-voltage battery 5 is in a thermal runaway state. Specifically, it queries the power management ECU 41C to determine whether or not the high-voltage battery 5 is in a thermal runaway state, and determines whether or not the high-voltage battery 5 is in a thermal runaway state based on the response information to the query. It is also conceivable that the power management ECU 41C is configured to output alert information to the bus 40 when it is determined that the high-voltage battery 5 is in a thermal runaway state, in which case the determination process in step S501 is a process to determine whether or not such alert information exists.

[0119] In step S501, if it is determined that the high-voltage battery 5 is not in a thermal runaway state, the control unit 13C proceeds to step S103 as described above. As a result, if the high-voltage battery 5 is not in a thermal runaway state, the control unit 13C controls the relay 12 to turn off in accordance with the determination that the remaining charge of the auxiliary battery 11 is below the first margin threshold and that the auxiliary battery 11 has been in a discharged state for a predetermined period of time or longer.

[0120] On the other hand, if the control unit 13C determines in step S501 that the high-voltage battery 5 is in a thermal runaway state, it proceeds to step S105 as described above. This enables a process in which, if the high-voltage battery 5 is in a thermal runaway state, the control unit 13C controls the relay 12 to turn off in accordance with the determination that the remaining charge of the auxiliary battery 11 is below the over-discharge prevention threshold.

[0121] In the illustrated example, the process for external notification in steps S107 and S108 is executed when the conditions in steps S103 and S104 are met, provided that the high-voltage battery 5 is not in a thermal runaway state. However, in the fourth embodiment, it is not essential to execute the processes in steps S107 and S108.

[0122] Furthermore, in the illustrated example, the external notification process in steps S107 and S108 is performed on the condition that the remaining charge of the auxiliary battery 11 falls below the first margin threshold. However, it is also conceivable that the external notification process in steps S107 and S108 be performed when it is determined that an abnormality has occurred in the auxiliary battery 11 that has led to smoke emission and fire (in the example of Figure 13, when it is determined in step S102 that the auxiliary battery 11 is in a thermal runaway state).

[0123] Furthermore, in the fourth embodiment, it is also possible to perform remaining charge display processing based on the second margin threshold, as in the case of the second embodiment. Figure 14 is a flowchart showing a specific example of the processing procedure that the control unit 13C should execute in that case. The difference from the processing shown in Figure 13 is that, in step S501, it is determined that the high-voltage battery 5 is not in a thermal runaway state, and in response to this, the processing of steps S201 and S202 described earlier is executed. In this case as well, if it is determined in step S201 that the remaining charge of the auxiliary battery 11 is not below the second margin threshold, the process is returned to step S101. Also, in response to the processing in step S202 which displays information indicating a remaining charge less than the actual remaining charge on the display unit 50, the process proceeds to step S103, and a determination based on the first margin threshold is made.

[0124] In this fourth embodiment, as in the third embodiment, a configuration can be adopted in which a process is performed to store the first margin threshold received from the power management ECU 41.

[0125] <5. Modifications> Herein, this embodiment is not limited to the specific examples described above, and various modifications can be adopted. For example, although the above example illustrates the case in which a lithium-ion battery is used as the auxiliary battery 11, the auxiliary battery 11 is not limited to a lithium-ion battery, but can be any battery that can be subject to low charge cutoff control (control to prevent over-discharge progression).

[0126] Furthermore, while the above example illustrates the application of this technology to HEVs, this technology can also be suitably applied to BEVs (Battery Electric Vehicles) that do not have an engine.

[0127] <6. Summary of Embodiments> As described above, the first control device as an embodiment (1, 1A, 1B) is a control device for a vehicle equipped with auxiliary equipment (3), an auxiliary battery (11) provided as a power source for the auxiliary equipment, a relay (12) inserted between the auxiliary battery and the auxiliary equipment, and a high-voltage battery (5) having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, comprising a control unit (13) that controls the on / off state of the relay, and a switch unit (20) that has a switch mechanism capable of switching between an on state and an off state, and outputs a signal to the control unit to instruct the relay to turn on when the switch mechanism is set to the on state. The control unit comprises one or more processors (CPU of the control unit 13) and a storage medium (ROM of the control unit 13) in which a program executed by the one or more processors is stored. The program includes one or more instructions, and the instructions cause one or more processors to execute the following: a process to turn off the relay when it is determined that the remaining charge of the auxiliary battery is below an over-discharge prevention threshold, and a process to turn off the relay when it is determined that the remaining charge of the auxiliary battery is below a first margin threshold which is greater than the over-discharge prevention threshold, and that the auxiliary battery has been in a discharged state for a predetermined time or longer.

[0128] With the switch section described above, even if power supply to the auxiliary equipment is stopped due to the low charge cut-off control for the protection of the auxiliary battery, if the user turns on the switch section, the relay will be forcibly turned on, enabling power supply to the auxiliary equipment. Once power supply to the auxiliary equipment is possible, the high-voltage system starts up, and the auxiliary battery can be charged by the high-voltage battery, so thereafter power supply from the auxiliary battery to the auxiliary equipment can be continued as usual. In other words, in this case, the only action required to deal with a dead battery is for the user to turn on the switch section. In this way, even when a lithium-ion battery is provided as the auxiliary battery, the complicated procedures for dealing with a dead battery are prevented. Furthermore, in this embodiment, a process is performed to turn off the relay when it is determined that the remaining charge of the auxiliary battery is below the over-discharge progression prevention threshold, and a process is performed to turn off the relay when it is determined that the remaining charge of the auxiliary battery is below the first margin threshold which is greater than the over-discharge progression prevention threshold, and the auxiliary battery has been in a discharged state for a predetermined period of time or longer. If the auxiliary battery continues to discharge for a predetermined period of time, it can be inferred that some abnormality has occurred in the auxiliary battery's charging system, such as the high-voltage battery being depleted, making it impossible to charge the auxiliary battery. In other words, when the auxiliary battery falls below the first margin threshold, the relay is turned off if charging from the high-voltage battery to the auxiliary battery is impossible. The relay is turned off when the auxiliary battery's remaining charge falls below the first margin threshold, which is greater than the over-discharge prevention threshold. Therefore, the relay is turned off when there is a certain margin remaining in the auxiliary battery. In this case, if the self-discharge is only a few days' worth, the high-voltage system can be activated by forcibly turning on the relay by operating the switch, making it possible to charge the auxiliary battery with the high-voltage battery. Therefore, if the cause of the auxiliary battery being unable to charge is the depletion of the high-voltage battery, the high-voltage battery can be charged after the high-voltage system is activated, making the vehicle drivable.In this case, there is no need to replace the auxiliary battery, thus avoiding the burden of significant replacement costs on the user. Furthermore, the workload involved in restoring the vehicle to a normally drivable state is reduced, preventing deterioration of maintainability. Additionally, if the cause of the auxiliary battery's inability to charge is a failure in the power supply system from the high-voltage battery to the auxiliary battery, such as a DC / DC converter failure, the high-voltage system can be activated by forcibly turning on the relay through the operation of the switch as described above. This allows the vehicle to be charged before being taken to a vehicle maintenance facility such as a dealer, where the faulty part can be repaired and the auxiliary battery can be restored to a state where it can be charged by the high-voltage battery. Again, there is no need to replace the auxiliary battery, thus avoiding the burden of significant replacement costs on the user. Furthermore, the workload involved in restoring the vehicle to a normally drivable state is reduced, preventing deterioration of maintainability. On the other hand, in this embodiment, regardless of whether the auxiliary battery has been discharged for a predetermined time or longer, if the remaining charge of the auxiliary battery falls below the over-discharge prevention threshold, the relay is turned off. In other words, if it is presumed that there is no abnormality in the auxiliary battery's charging system, the over-discharge prevention control is performed as in the conventional method.

[0129] Furthermore, in the first control device as an embodiment, a communication ECU (42) capable of communicating with an external device, which is an information processing device outside the vehicle, is provided. The command causes one or more processors to execute a process in which, when the remaining charge of the auxiliary battery is below a first margin threshold and the auxiliary battery is in a discharged state, the state continues for a predetermined time or longer, and it is predicted that the relay will be turned off, the communication ECU will send predetermined notification information to the external device. This makes it possible to notify a user terminal such as a smartphone via the external device that the remaining charge of the auxiliary battery has fallen below the first margin threshold and the relay has been turned off. Therefore, it is possible to make the user aware that the auxiliary battery has run out of power, and to ensure that corrective measures are taken before the remaining power of the auxiliary battery is depleted, that is, while the high-voltage system is still in a state where it can be started.

[0130] Furthermore, in the first control device as an embodiment, an in-vehicle ECU (power management ECU 41, communication ECU 42, other ECU 43) capable of communicating with one or more processors is provided. The instruction causes one or more processors to execute a process to notify the in-vehicle ECU when it is predicted that the relay will be turned off, and the in-vehicle ECU, in response to the notification, performs a process to write the RAM's held values ​​to non-volatile memory. This makes it possible to save the RAM's held values ​​to non-volatile memory before the in-vehicle ECU goes into a power loss state in response to the relay being turned off. Therefore, it is possible to prevent the loss of various learned values ​​and necessary information such as DCT (Diagnostic Trouble Code) of the in-vehicle ECU due to the relay being turned off. For example, it is possible to prevent malfunctions such as learning being reset or faults being overlooked.

[0131] Furthermore, in the first control device (1A) as an embodiment, the command causes one or more processors to perform the following: determine whether the remaining charge of the auxiliary battery has fallen below a second margin threshold, which is greater than the first margin threshold; and, in response to the determination that the remaining charge of the auxiliary battery has fallen below the second margin threshold, to display information on the in-vehicle display unit indicating a remaining charge less than the actual remaining charge as information related to the remaining charge of the auxiliary battery. As described above, by displaying information related to the remaining charge of the auxiliary battery on the in-vehicle display unit in response to the remaining charge of the auxiliary battery falling below a second margin threshold, which is greater than the first margin threshold, it becomes possible to make the driver aware that the remaining charge of the auxiliary battery is low before the relay is actually turned off, that is, before the power supply to the auxiliary equipment is forcibly stopped, thereby preventing the driver from making a mistake due to anxiety or loss of composure. At this time, by displaying information indicating a remaining charge less than the actual remaining charge as information related to the remaining charge of the auxiliary battery, it is possible to encourage the driver to take early action, and it is possible to make it less likely for the power supply to the auxiliary equipment to be forcibly stopped by turning off the relay.

[0132] Furthermore, in the first control device (1B) as an embodiment, an on-board ECU (power management ECU 41) is provided in which the first margin threshold is stored, and the command causes one or more processors to execute a process to store the first margin threshold received from the on-board ECU. This makes it possible to eliminate the need for the supplier of the auxiliary battery unit to manage the first margin threshold for each manufacturer and vehicle model when the setting value of the first margin threshold differs depending on the vehicle manufacturer and vehicle model. Therefore, the burden on the supplier can be reduced.

[0133] Furthermore, the first vehicle of the embodiment (100, 100A, 100B) is a vehicle comprising: auxiliary equipment; an auxiliary battery provided as a power source for the auxiliary equipment; a relay inserted between the auxiliary battery and the auxiliary equipment; and a high-voltage battery having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, the vehicle comprising: a control unit that controls the on / off state of the relay; and a switch unit having a switch mechanism that can switch between an on state and an off state, and which outputs a signal to the control unit to instruct the relay to be turned on when the switch mechanism is set to the on state. The control unit comprises one or more processors and a storage medium storing a program executed by the one or more processors. The program includes one or more instructions, each instruction causing one or more processors to perform the following actions: turning off the relay when it is determined that the remaining charge of the auxiliary battery is below an over-discharge prevention threshold; and turning off the relay when it is determined that the remaining charge of the auxiliary battery is below a first margin threshold greater than the over-discharge prevention threshold and that the auxiliary battery is in a discharged state for a predetermined period of time or longer. The same operation and effects as the first control device as described above can be obtained with such a first vehicle.

[0134] A second control device (1C) as an embodiment is a control device for a vehicle comprising: auxiliary equipment (3); an auxiliary battery (11) provided as a power source for the auxiliary equipment; a relay (12) inserted between the auxiliary battery and the auxiliary equipment; and a high-voltage battery (5) having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, comprising: a control unit (13C) that controls the on / off state of the relay; and a switch unit (20) having a switch mechanism that can switch between an on state and an off state, and which outputs a signal to the control unit to instruct the relay to be turned on when the switch mechanism is set to the on state. The control unit comprises one or more processors (CPU of the control unit 13C) and a storage medium (ROM of the control unit 13C) in which a program executed by the one or more processors is stored. The program includes one or more instructions, and the instructions cause one or more processors to perform the following: determine whether or not an abnormality has occurred that could lead to smoke and fire in the high-voltage battery; if it is determined that no abnormality has occurred, control the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below a first margin threshold greater than the over-discharge progression prevention threshold and that the auxiliary battery has been in a discharged state for a predetermined period of time or longer; and if it is determined that an abnormality has occurred, control the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below the over-discharge progression prevention threshold.

[0135] In this second control device, the control unit is equipped with a switch that outputs a signal to turn on the relay, and it is also configured to control the relay to turn off when it is determined that the remaining charge of the auxiliary battery is below a first margin threshold which is greater than the over-discharge prevention threshold, and that the auxiliary battery has been in a discharged state for a predetermined period of time or longer. As mentioned above, if the auxiliary battery has been in a discharged state for a predetermined period of time or longer, it can be inferred that some abnormality has occurred in the auxiliary battery's charging system, such as the high-voltage battery being depleted, and the auxiliary battery is in a state where it cannot be charged. In other words, with the processing described above, when the auxiliary battery falls below the first margin threshold, and it is impossible to charge the auxiliary battery from the high-voltage battery, the relay will be turned off. Since the relay is turned off when the remaining charge of the auxiliary battery falls below the first margin threshold which is greater than the over-discharge prevention threshold, the relay will be turned off when there is a certain amount of margin remaining in the auxiliary battery. Therefore, in this case, if the self-discharge is only a few days, the high-voltage system can be activated by forcibly turning on the relay through the switch, making the auxiliary battery rechargeable by the high-voltage battery. Thus, if the reason the auxiliary battery cannot be charged is due to the depletion of the high-voltage battery, the high-voltage battery can be charged after the high-voltage system is activated, making the vehicle drivable. At this time, there is no need to replace the auxiliary battery, thus avoiding the burden of large replacement costs on the user, and the workload of returning the vehicle to a normally drivable state is also reduced, preventing deterioration of maintainability. Furthermore, if the reason the auxiliary battery cannot be charged is a failure in the power supply system from the high-voltage battery to the auxiliary battery, such as a failure of the DC / DC converter, the high-voltage system can be activated by forcibly turning on the relay through the switch as described above, allowing the high-voltage battery to be charged before the vehicle can be taken to a vehicle maintenance facility such as a dealer, where the faulty part can be repaired and the auxiliary battery can be returned to a state where it can be charged by the high-voltage battery.In this case, there is no need to replace the auxiliary battery, thus avoiding the burden of significant replacement costs on the user. Furthermore, the workload for returning the vehicle to a normally drivable state is reduced, preventing deterioration of maintainability. However, if an abnormality occurs in the high-voltage battery that leads to smoke and fire, the high-voltage battery will be shut off, and power supply to the auxiliary equipment from the DC / DC converter will become impossible. As a result, power to the auxiliary equipment will be supplied solely by the auxiliary battery. In such a situation, if the relay is turned off based on the first margin threshold as described above, even if there is sufficient remaining charge in the auxiliary battery, the cooling system for the high-voltage battery, electric power steering, electronically controlled brakes, and other controls related to driving will stop, potentially making it difficult to ensure the safety of the occupants. Therefore, the second control device determines whether an abnormality has occurred in the high-voltage battery that leads to smoke and fire. If such an abnormality occurs, instead of turning off the relay based on the first margin threshold, it controls the relay to turn off based on the determination that the remaining charge of the auxiliary battery is below the over-discharge prevention threshold. This allows for the continuation of driving-related control as much as possible even if a high-voltage battery malfunction occurs that leads to smoke or fire, thereby improving safety. Consequently, it enables appropriate auxiliary battery shutdown control according to the vehicle's condition.

[0136] Furthermore, in the second control device as an embodiment, a communication ECU (42) capable of communicating with an external device, which is an information processing device outside the vehicle, is provided. The command causes one or more processors to execute a process in which, when no abnormality has occurred, the remaining charge of the auxiliary battery is below the first margin threshold and the auxiliary battery is in a discharged state, and it is predicted that the relay will be turned off if this condition continues for a predetermined time or longer, the communication ECU will send predetermined notification information to the external device. This makes it possible to notify a user terminal such as a smartphone via the external device that the remaining charge of the auxiliary battery has fallen below the first margin threshold and the relay has been turned off. Therefore, it is possible to make the user aware that the auxiliary battery has run out of power, and to ensure that corrective measures are taken before the auxiliary battery runs out of power, that is, while the high-voltage system is still in a state where it can be started.

[0137] Furthermore, in the second control device as an embodiment, the command causes one or more processors to execute the following processes: a process to determine whether or not an abnormality has occurred in the auxiliary battery that could lead to smoke and fire; a process to control the relay to turn off in response to the determination that an abnormality has occurred in the auxiliary battery that could lead to smoke and fire; and a process to cause a predetermined notification information to be sent to an external device via a communication ECU when it is determined that an abnormality has occurred in the auxiliary battery that could lead to smoke and fire. As a result, even if an abnormality occurs in the auxiliary battery that could lead to smoke and fire, it is possible to notify the user terminal such as a smartphone via an external device. Therefore, the user can be made aware that an abnormality has occurred in the auxiliary battery even if they are away from the vehicle.

[0138] Furthermore, in the second control device as an embodiment, an in-vehicle ECU (power management ECU 41, communication ECU 42, other ECU 43) capable of communicating with one or more processors is provided. The instruction causes one or more processors to execute a process to notify the in-vehicle ECU when it is predicted that the relay will be turned off, and the in-vehicle ECU, in response to the notification, performs a process to write the RAM's held values ​​to non-volatile memory. This makes it possible to save the RAM's held values ​​to non-volatile memory before the in-vehicle ECU goes into a power loss state in response to the relay being turned off. Therefore, it is possible to prevent the loss of various learned values ​​and necessary information such as DCT (Diagnostic Trouble Code) of the in-vehicle ECU due to the relay being turned off. For example, it is possible to prevent malfunctions such as learning being reset or failures being overlooked.

[0139] Furthermore, in the second control device as an embodiment, the command causes one or more processors to perform the following: a process to determine whether the remaining charge of the auxiliary battery has fallen below a second margin threshold, which is greater than the first margin threshold, when it is determined that no abnormality has occurred; and a process to display information on the in-vehicle display unit indicating a remaining charge less than the actual remaining charge, as information related to the remaining charge of the auxiliary battery, in response to the determination that the remaining charge of the auxiliary battery has fallen below the second margin threshold. As described above, by displaying information related to the remaining charge of the auxiliary battery on the in-vehicle display unit in response to the remaining charge of the auxiliary battery falling below a second margin threshold, which is greater than the first margin threshold, it becomes possible to make the driver aware that the remaining charge of the auxiliary battery is low before the relay is actually turned off, that is, before the power supply to the auxiliary equipment is forcibly stopped, thereby preventing the driver from making a mistake due to anxiety or loss of composure. At this time, by displaying information regarding the remaining charge of the auxiliary battery that shows a lower remaining charge than the actual remaining charge, it is possible to encourage the driver to take early action and reduce the likelihood of forced power supply to auxiliary equipment being shut off due to relay off.

[0140] Furthermore, in the second control device as an embodiment, an on-board ECU (power management ECU 41) is provided in which the first margin threshold is stored, and the command causes one or more processors to execute a process to store the first margin threshold received from the on-board ECU. This eliminates the need for the supplier of the auxiliary battery unit to manage the first margin threshold for each manufacturer and vehicle model when the setting value of the first margin threshold differs depending on the vehicle manufacturer and vehicle model. Therefore, the burden on the supplier can be reduced.

[0141] The second vehicle of the embodiment (100C) is a vehicle comprising: auxiliary equipment; an auxiliary battery provided as a power source for the auxiliary equipment; a relay inserted between the auxiliary battery and the auxiliary equipment; and a high-voltage battery having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, the vehicle comprising: a control unit that controls the on / off state of the relay; and a switch unit having a switch mechanism that can switch between an on state and an off state, and which outputs a signal to the control unit to instruct the relay to be turned on when the switch mechanism is set to the on state. The control unit comprises one or more processors and a storage medium storing a program executed by the one or more processors, the program including one or more instructions, the instructions causing one or more processors to perform the following: a process to determine whether or not an abnormality has occurred that could lead to smoke and fire in the high-voltage battery; if it is determined that no abnormality has occurred, the control unit to turn off the relay in accordance with the determination that the remaining charge of the auxiliary battery is below a first margin threshold greater than the over-discharge prevention threshold and that the auxiliary battery has been in a discharged state for a predetermined period of time or longer; and if it is determined that an abnormality has occurred, the control unit to turn off the relay in accordance with the determination that the remaining charge of the auxiliary battery is below the over-discharge prevention threshold. The same operation and effects as the second control device as the embodiment described above can be obtained with such a second vehicle as well.

[0142] 100, 100A, 100B, 100C Vehicle 1, 1A, 1B, 1C Control unit 2 Engine 3 Auxiliary equipment 4 MG (Motor Generator) 5 High-voltage battery 6 Inverter 7 DC / DC converter 10, 10C Auxiliary battery unit 11 Auxiliary battery 12 Relay 13, 13C Control unit 20 Switch unit 21 Switch signal supply unit Ru, Rd Resistor Ts Switch signal terminal Tg GND terminal Tp Positive terminal Tm Negative terminal Td Data terminal 20a Terminal unit 25 Fuse 30 Fuse box 40 Bus 41, 41C Power management ECU 42 Communication ECU 43 Other ECUs 44 Display control ECU 50 Display unit

Claims

1. A control device for a vehicle comprising: auxiliary equipment; an auxiliary battery provided as a power source for the auxiliary equipment; a relay inserted between the auxiliary battery and the auxiliary equipment; and a high-voltage battery having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, comprising: a control unit that controls the on / off state of the relay; a switch unit having a switch mechanism that can switch between an on state and an off state, and which outputs a signal to the control unit to instruct the relay to be turned on when the switch mechanism is turned on, wherein the control unit comprises: one or more processors; and a storage medium storing a program executed by the one or more processors, wherein the program includes one or more instructions, and the instructions include: a process to determine whether or not an abnormality has occurred in the high-voltage battery that could lead to smoke or fire; A control device that, when it is determined that the aforementioned abnormality has occurred, controls the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below a first margin threshold which is greater than the over-discharge progression prevention threshold and that the auxiliary battery has been in a discharged state for a predetermined period of time or longer; and when it is determined that the aforementioned abnormality has not occurred, controls the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below the over-discharge progression prevention threshold.

2. The control device according to claim 1, comprising a communication ECU capable of communicating with an external device which is an information processing device outside the vehicle, wherein the instruction causes one or more processors to execute a process to send predetermined notification information to the external device via the communication ECU when it is determined that no abnormality has occurred, and when it is predicted that the relay will be turned off because the remaining charge of the auxiliary battery is below the first margin threshold and the auxiliary battery is in a discharged state for a predetermined time or longer.

3. The control device according to claim 2, wherein the instruction causes one or more processors to perform the following: a process to determine whether or not an abnormality has occurred in the auxiliary battery that could lead to smoke and fire; a process to turn off the relay in response to the determination that an abnormality has occurred in the auxiliary battery that could lead to smoke and fire; and a process to cause the communication ECU to transmit predetermined notification information to the external device when it has been determined that an abnormality has occurred in the auxiliary battery that could lead to smoke and fire.

4. The control device according to claim 1, comprising an in-vehicle ECU capable of communicating with one or more processors, wherein the instruction causes one or more processors to perform a process to notify the in-vehicle ECU when it is predicted that the relay will be turned off, and the in-vehicle ECU performs a process to write the RAM's held value to a non-volatile memory in response to the notification.

5. The control device according to claim 1, wherein the instruction causes one or more processors to perform the following: a process to determine whether the remaining charge of the auxiliary battery has fallen below a second margin threshold which is greater than the first margin threshold, when it has determined that the abnormality has not occurred; and a process to display information on the vehicle's display unit indicating a remaining charge less than the actual remaining charge, as information relating to the remaining charge of the auxiliary battery, in response to the determination that the remaining charge of the auxiliary battery has fallen below the second margin threshold.

6. A control device according to any one of claims 1 to 4, comprising an in-vehicle ECU in which the first margin threshold is stored, wherein the instruction causes one or more processors to perform a process of storing the first margin threshold received from the in-vehicle ECU.

7. A vehicle comprising: auxiliary equipment; an auxiliary battery provided as a power source for the auxiliary equipment; a relay inserted between the auxiliary battery and the auxiliary equipment; and a high-voltage battery having a rated output voltage higher than that of the auxiliary battery and capable of being used as a power source for charging the auxiliary battery, wherein the vehicle comprises: a control unit that controls the on / off state of the relay; a switch unit having a switch mechanism that can switch between an on state and an off state, and which outputs a signal to the control unit to instruct the relay to be turned on when the switch mechanism is turned on, the control unit comprising: one or more processors; and a storage medium storing a program executed by the one or more processors, the program comprising: one or more instructions, the instructions including: a process to determine whether or not an abnormality has occurred in the high-voltage battery that could lead to smoke or fire; A vehicle that, if it is determined that no abnormality has occurred, controls the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below a first margin threshold which is greater than the over-discharge progression prevention threshold and that the auxiliary battery has been in a discharged state for a predetermined period of time or longer; and if it is determined that an abnormality has occurred, controls the relay to turn off in accordance with the determination that the remaining charge of the auxiliary battery is below the over-discharge progression prevention threshold.

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