Control device

Abstract

Provided is a control device for a vehicle including an auxiliary device and an auxiliary device battery storing power to be supplied to the auxiliary device, the control device including one or more processors, and one or more memories connected to the processors. The processors execute processing including: temporarily executing voltage determination for determining whether or not a voltage of the auxiliary device battery is equal to or less than a threshold value under a situation where an ignition of the vehicle is turned off; executing charging control for charging the auxiliary device battery if it is determined in the voltage determination that the voltage is equal to or less than the threshold value; and determining a determination timing at which the voltage determination is executed on the basis of an operation state of the auxiliary device.

Description

Control device

[0001] The present invention relates to a control device.

[0002] A vehicle is equipped with auxiliary devices such as a loop lamp. The auxiliary devices operate using power from an auxiliary battery installed in the vehicle. However, when the vehicle is parked for a long period of time, the power stored in the auxiliary battery may decrease due to natural discharge, which may result in the auxiliary battery running out of power. Therefore, in order to prevent the auxiliary battery from running out of power, a charging control technique for charging the auxiliary battery while the vehicle ignition is off has been proposed, as described in Patent Document 1, for example.

[0003] JP 2014-090630 A

[0004] However, there are cases where a vehicle is parked with auxiliary equipment such as a loop lamp operating. In such cases, the power stored in the auxiliary battery may decrease due to the continued operation of the auxiliary equipment, which may result in the auxiliary battery running out of power. Therefore, even in such cases, it is desirable to prevent the auxiliary battery from running out of power.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control device that can prevent the auxiliary battery from running out of power.

[0006] In order to solve the above problem, a control device according to one embodiment of the present invention is a control device for a vehicle including an auxiliary device and an auxiliary battery that stores power supplied to the auxiliary device, wherein the control device has one or more processors and one or more memories connected to the processors, and the processor performs processing including: temporarily performing a voltage determination to determine whether the voltage of the auxiliary battery is below a threshold value when the ignition of the vehicle is off; performing charging control to charge the auxiliary battery when the voltage determination determines that the voltage is below the threshold value; and determining the determination timing for performing the voltage determination based on the operating state of the auxiliary device.

[0007] According to the present invention, it is possible to prevent the auxiliary battery from running out of power.

[0008] FIG. 1 is a schematic diagram showing a general configuration of a vehicle according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of a functional configuration of a control device according to an embodiment of the present invention. FIG. 3 is a graph showing an example of a transition in the voltage of an auxiliary battery after the ignition of a vehicle according to a comparative example is turned off. FIG. 4 is a flowchart showing an example of the overall processing flow performed by the control device according to an embodiment of the present invention. FIG. 5 is a flowchart showing an example of the flow of a process for determining the timing of a first determination performed by the control device according to an embodiment of the present invention. FIG. 6 is a flowchart showing an example of the flow of a process for determining the timing of a next determination performed by the control device according to an embodiment of the present invention.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0010] <Configuration of Vehicle> The configuration of a vehicle 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

[0011] Fig. 1 is a schematic diagram showing the overall configuration of a vehicle 1. As shown in Fig. 1, the vehicle 1 includes a main battery 10, an inverter 20, a traction motor 30, a DC-DC converter 40, an auxiliary battery 50, auxiliary equipment 60, an ignition sensor 71, a voltage sensor 72, a temperature sensor 73, and a control device 80.

[0012] The vehicle 1 is an electric vehicle equipped with a traction motor 30 as a drive source. However, the vehicle 1 described below is merely one example of a vehicle according to the present invention, and as will be described later, the vehicle according to the present invention may also be a hybrid vehicle or an engine vehicle.

[0013] The main battery 10 stores the power supplied to the traction motor 30. The main battery 10 is a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The main battery 10 is connected to the traction motor 30 via an inverter 20.

[0014] The inverter 20 is a power conversion device capable of converting power between direct current and alternating current. The inverter 20 includes, for example, a multi-phase bridge circuit. The inverter 20 can convert direct current power supplied from the main battery 10 into alternating current power and supply it to the traction motor 30. The inverter 20 is provided with switching elements, and the supply of power between the main battery 10 and the traction motor 30 is controlled by controlling the operation of the switching elements.

[0015] The traction motor 30 is capable of outputting power for driving the drive wheels W of the vehicle 1. The traction motor 30 is, for example, a polyphase AC motor such as a three-phase AC motor. The traction motor 30 generates power using power supplied from the main battery 10 via the inverter 20. The traction motor 30 may also have a regenerative function, which functions as a generator that generates power using the rotational energy of the drive wheels W when the vehicle 1 decelerates. In this case, the AC power regenerated by the traction motor 30 is converted into DC power by the inverter 20 and supplied to the main battery 10.

[0016] The DC-DC converter 40 is a voltage conversion device capable of converting voltages. The DC-DC converter 40 is provided between the main battery 10 and the auxiliary battery 50. The DC-DC converter 40 can reduce the voltage of the power stored in the main battery 10 and supply the power to the auxiliary battery 50. The DC-DC converter 40 includes, for example, a chopper circuit, and the voltage conversion by the DC-DC converter 40 is controlled by controlling the operation of a switching element provided in the chopper circuit.

[0017] The auxiliary battery 50 stores the power supplied to the auxiliary device 60. The auxiliary battery 50 is, for example, a secondary battery such as a lead-acid battery or a lithium-ion battery. The auxiliary battery 50 has a lower voltage than the main battery 10. For example, the voltage of the auxiliary battery 50 is about 12 V when fully charged. The auxiliary battery 50 is connected to the auxiliary device 60.

[0018] The auxiliary devices 60 include various devices that operate using the power stored in the auxiliary battery 50. Examples of the auxiliary devices 60 include lighting devices such as a room lamp and a headlamp, air conditioning equipment, and audio equipment.

[0019] The ignition sensor 71 detects the state of the ignition switch of the vehicle 1 and outputs the state to the control device 80. The driver of the vehicle 1 can change the state of the electrical system of the vehicle 1 by operating the ignition switch. The driver of the vehicle 1 can switch the ignition of the vehicle 1 from on to off by operating the ignition switch. The driver of the vehicle 1 parks the vehicle 1 with the ignition of the vehicle 1 turned off. When the ignition of the vehicle 1 is turned off, it becomes impossible to supply power from at least the main battery 10 to the traction motor 30, and the vehicle 1 becomes unable to run. Furthermore, as will be described later, when the ignition of the vehicle 1 is turned off, the supply of power to part of the control device 80 is stopped, and the functions of the control device 80 become limited.

[0020] In this specification, a state in which the ignition is not turned off is collectively referred to as a state in which the ignition is turned on. However, among the states in which the ignition is turned on, there may be a plurality of states in which the electrical system of the vehicle 1 is in a different state. These states may be distinguished by different names. For example, a state in which power can be supplied from the main battery 10 to the traction motor 30 may be distinguished by different names from a state in which power cannot be supplied from the main battery 10 to the traction motor 30 but all of the accessories 60 are operable.

[0021] The voltage sensor 72 detects the voltage of the auxiliary battery 50 and outputs the detected voltage to the control device 80 .

[0022] The temperature sensor 73 detects the temperature of the auxiliary battery 50 and outputs the detected temperature to the control device 80 .

[0023] The control device 80 has one or more processors 81 and one or more memories 82 connected to the processors 81. The processor 81 includes, for example, a CPU (Central Processing Unit). The memory 82 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM is a storage element that stores programs used by the CPU, calculation parameters, and the like. The RAM is a storage element that temporarily stores data such as variables and parameters used in processing executed by the CPU.

[0024] 1 , the processor 81 includes a first processor 81a and a second processor 81b. The control device 80 has a power supply, and when the ignition of the vehicle 1 is turned off, power is supplied from the power supply to the first processor 81a, but power is not supplied from the power supply to the second processor 81b. In other words, when the ignition of the vehicle 1 is turned off, the function of the second processor 81b is basically limited. However, the first processor 81a and the second processor 81b may be arranged together in a single processor 81 without being clearly separated.

[0025] The control device 80 communicates with the inverter 20, the DCDC converter 40, the auxiliary device 60, the ignition sensor 71, the voltage sensor 72, and the temperature sensor 73. Specifically, the control device 80 can control the operation of each of these devices by outputting operation commands to the inverter 20, the DCDC converter 40, and the auxiliary device 60. The control device 80 can also acquire information from the auxiliary device 60, the ignition sensor 71, the voltage sensor 72, and the temperature sensor 73. The communication between the control device 80 and each device is realized, for example, by using CAN (Controller Area Network) communication.

[0026] Fig. 2 is a block diagram showing an example of the functional configuration of the control device 80. For example, as shown in Fig. 2, the control device 80 includes a processing unit 81a1, a control unit 81b1, and a communication unit 81b2.

[0027] Various processes performed by the processing unit 81a1, including the processes described below, can be executed by the first processor 81a. In detail, the various processes performed by the processing unit 81a1 are executed by the first processor 81a executing programs stored in the memory 82.

[0028] Furthermore, various processes, including the processes described below, performed by the control unit 81b1 and the communication unit 81b2 may be executed by the second processor 81b. Specifically, the various processes performed by the control unit 81b1 and the communication unit 81b2 are executed by the second processor 81b executing programs stored in the memory 82.

[0029] The functions of the control device 80 according to the present embodiment may be divided among multiple devices, or multiple functions may be realized by a single device. When the functions of the control device 80 are divided among multiple devices, the multiple devices may be connected to each other via a communication bus such as a CAN.

[0030] The processing unit 81a1 has a function of waking up the second processor 81b. Waking up the second processor 81b means supplying power to the second processor 81b from the power supply of the control device 80 so that the second processor 81b can perform its functions.

[0031] The control unit 81b1 has a function of controlling the operation of each device of the vehicle 1. Specifically, the control unit 81b1 can control the operation of each device by outputting operation commands to the inverter 20, the DCDC converter 40, and the auxiliary equipment 60.

[0032] The communication unit 81b2 has a function of outputting various types of information. For example, the communication unit 81b2 can transmit information to an information processing terminal such as a smartphone carried by the driver who is the user of the vehicle 1.

[0033] <Operation of the Control Device> Next, the operation of the control device 80 according to the embodiment of the present invention will be described with reference to FIGS.

[0034] As described above, the vehicle 1 is provided with the auxiliary device 60 that operates using power from the auxiliary battery 50. Here, if the vehicle 1 is parked with the auxiliary device 60 operating after the ignition of the vehicle 1 is turned off, the power stored in the auxiliary battery 50 decreases due to the auxiliary device 60 continuing to operate.

[0035] 3 is a graph showing an example of a change in voltage V of auxiliary battery 50 after the ignition of vehicle 1 according to a comparative example is turned off. The horizontal axis of FIG. 3 represents time T, and the vertical axis of FIG. 3 represents voltage V of auxiliary battery 50.

[0036] 3 shows lines L1, L2, and L3 that indicate the transition of voltage V of auxiliary battery 50. Line L1 indicates the transition of voltage V when both the headlamp and the room lamp of auxiliary device 60 are activated. Line L2 indicates the transition of voltage V when only the headlamp of auxiliary device 60 is activated. Line L3 indicates the transition of voltage V when only the room lamp of auxiliary device 60 is activated.

[0037] In the example of FIG. 3 , the ignition is switched from on to off at time T0. At time T0, the voltage V of the auxiliary battery 50 is voltage V0. Then, in the examples of lines L1, L2, and L3, the voltage V of the auxiliary battery 50 decreases over time after time T0. Here, the rate of decrease in voltage V is greatest in the example of line L1, next greatest in the example of line L2, and least in the example of line L3. In this way, the rate of decrease in voltage V can vary depending on the operating state of the auxiliary device 60.

[0038] Voltage V1 in Figure 3 is the voltage V required to turn on the ignition and enable the supply of power from the main battery 10 to the traction motor 30. In other words, if the voltage V of the auxiliary battery 50 falls below voltage V1, it will be impossible to turn on the ignition and enable the supply of power from the main battery 10 to the traction motor 30. Voltage V2 in Figure 3 is the voltage V that ensures normal operation of the control device 80. In other words, if the voltage V of the auxiliary battery 50 falls below voltage V2, the control device 80 will not be able to operate normally. Voltage V2 is lower than voltage V1.

[0039] As shown by line L1, if the ignition is turned off with both the headlamps and the room lamps activated, the voltage V of the auxiliary battery 50 falls below voltage V1 at time T1. Furthermore, as shown by line L2, if the ignition is turned off with only the headlamps activated, the voltage V of the auxiliary battery 50 falls below voltage V1 at time T2, which is later than time T1. Furthermore, as shown by line L3, if the ignition is turned off with only the room lamp activated, the voltage V of the auxiliary battery 50 falls below voltage V1 at time T3, which is later than time T2. Thus, the timing at which the voltage V of the auxiliary battery 50 falls below voltage V1 after the ignition is turned off may vary depending on the operating state of the auxiliary equipment 60.

[0040] As described above, there is a risk that the auxiliary battery 50 will run out of power if the auxiliary device 60 continues to operate after the ignition of the vehicle 1 is turned off. Therefore, in this embodiment, while the ignition of the vehicle 1 is turned off, the control unit 81b1 temporarily performs a voltage determination to determine whether the voltage V of the auxiliary battery 50 is equal to or lower than a threshold value Vth. The threshold value Vth is higher than the voltage V1. If the voltage determination determines that the voltage V is equal to or lower than the threshold value Vth, the control unit 81b1 performs charging control to charge the auxiliary battery 50. In this embodiment, as described below, the timing at which the voltage determination is performed is devised to prevent the auxiliary battery 50 from running out of power. The charging control process performed by the control device 80 will now be described.

[0041] Fig. 4 is a flowchart showing an example of the overall processing flow performed by the control device 80. The control flow shown in Fig. 4 is started when the ignition of the vehicle 1 is switched from on to off. Note that the control device 80 can determine that the ignition of the vehicle 1 has been switched from on to off based on, for example, the detection result of the ignition sensor 71.

[0042] When the control flow shown in FIG. 4 starts, first, in step S101, the processing unit 81a1 determines the determination timing for the first voltage determination.

[0043] 5 is a flowchart showing an example of the flow of the initial determination timing determination process performed by the control device 80. The control flow shown in FIG. 5 is executed in step S101 in the control flow shown in FIG.

[0044] When the control flow shown in FIG. 5 starts, first, in step S201, the processing unit 81a1 estimates the rate of decrease of the voltage V.

[0045] In step S201, the processing unit 81a1 estimates the rate of decrease of the voltage V based on the operating state of the auxiliary equipment 60. The processing unit 81a1 estimates the rate of decrease of the voltage V based on, for example, the type of auxiliary equipment 60 that is operating. For example, if only the headlamps are operating, the processing unit 81a1 estimates that the rate of decrease of the voltage V is the rate of decrease that would be expected if only the headlamps were operating. Also, for example, if only the room lamp is operating, the processing unit 81a1 estimates that the rate of decrease of the voltage V is the rate of decrease that would be expected if only the room lamp were operating. Also, for example, if both the headlamps and the room lamp are operating, the processing unit 81a1 estimates that the rate of decrease of the voltage V is the sum of the rate of decrease that would be expected if only the headlamps were operating and the rate of decrease that would be expected if only the room lamp were operating.

[0046] If operation modes with different power consumption amounts can be selected for the same accessory 60, the processing unit 81a1 may take into account the operation mode of the operating accessory 60 when estimating the rate of decrease in the voltage V. For example, if an operation mode in which the entire room lamp is turned on and an operation mode in which only a part of the room lamp is turned on can be selected and the room lamp is operating, the processing unit 81a1 may take into account the operation mode of the room lamp when estimating the rate of decrease in the voltage V.

[0047] Here, the rate at which voltage V decreases varies depending on the resistance value in the electric circuit formed by auxiliary battery 50 and auxiliary device 60. Therefore, it is preferable that processing unit 81a1 estimates the rate at which voltage V decreases by taking into account various parameters that affect the resistance value in such an electric circuit.

[0048] For example, the processing unit 81a1 may estimate the rate of decrease of the voltage V based on the temperature of the auxiliary battery 50 in addition to the operating state of the auxiliary device 60. The internal resistance of the auxiliary battery 50 may change depending on the temperature of the auxiliary battery 50. Therefore, for example, even when the operating state of the auxiliary device 60 is the same, the processing unit 81a1 may vary the estimated value of the rate of decrease of the voltage V depending on the temperature of the auxiliary battery 50. Note that the control device 80 can obtain the temperature of the auxiliary battery 50 based on the detection result of the temperature sensor 73, for example.

[0049] Furthermore, for example, the processing unit 81a1 may estimate the rate of decrease in voltage V based on the degree of deterioration of auxiliary battery 50 in addition to the operating state of auxiliary equipment 60. The internal resistance of auxiliary battery 50 may change depending on the degree of deterioration of auxiliary battery 50. Therefore, for example, even when the operating state of auxiliary equipment 60 is the same, the processing unit 81a1 may vary the estimated value of the rate of decrease in voltage V depending on the degree of deterioration of auxiliary battery 50. Note that the processing unit 81a1 can estimate the degree of deterioration of auxiliary battery 50 based on, for example, the elapsed time since the production date of auxiliary battery 50.

[0050] In the above description, the temperature of the auxiliary battery 50 and the degree of deterioration of the auxiliary battery 50 are described as information that can be taken into account with respect to the operating state of the auxiliary device 60 when estimating the rate at which the voltage V drops. However, the processing unit 81a1 may use multiple types of information as information that can be taken into account with respect to the operating state of the auxiliary device 60 when estimating the rate at which the voltage V drops. For example, the processing unit 81a1 may estimate the rate at which the voltage V drops based on the temperature of the auxiliary battery 50 and the degree of deterioration of the auxiliary battery 50 in addition to the operating state of the auxiliary device 60. Furthermore, the processing unit 81a1 may use information other than the above-described information as information that can be taken into account with respect to the operating state of the auxiliary device 60 when estimating the rate at which the voltage V drops. For example, the processing unit 81a1 may use information related to the resistance value of a harness connecting the auxiliary battery 50 and the auxiliary device 60 as information that can be taken into account with respect to the operating state of the auxiliary device 60 when estimating the rate at which the voltage V drops.

[0051] Next, in step S202, the processing unit 81a1 determines the timing of the first voltage determination after the ignition is turned off based on the voltage V when the ignition is turned off and the estimated value of the rate of decrease of the voltage V, and the control flow shown in Fig. 5 ends. Note that the timing when the ignition is turned off means the timing when the ignition is switched from on to off and then turned off.

[0052] In step S202, the processing unit 81a1 determines, for example, the timing at which the voltage V is expected to fall below the threshold value Vth as the timing for the initial voltage determination. For example, the processing unit 81a1 divides the difference between the voltage V when the ignition is off and the threshold value Vth by the estimated value of the rate of decrease of the voltage V estimated in step S201. The value obtained in this manner corresponds to the time from when the ignition is turned off to when the voltage V is expected to fall below the threshold value Vth. The processing unit 81a1 then determines, as the timing for the initial voltage determination, the timing at which this time has elapsed since the ignition was turned off. Note that the control device 80 can obtain the voltage V at each time point based on, for example, the detection result of the voltage sensor 72.

[0053] 4, in step S102, the processing unit 81a1 determines whether it is time to perform the initial voltage determination. As described above, when the ignition is turned off, the first processor 81a, which realizes the functions of the processing unit 81a1, receives power from the power supply of the control device 80. Therefore, the processing unit 81a1 can count time.

[0054] If it is determined that the timing for the first voltage determination has not yet arrived (NO in step S102), step S102 is repeated. On the other hand, if it is determined that the timing for the first voltage determination has arrived (YES in step S102), the process proceeds to step S103.

[0055] If the determination in step S102 is YES, in step S103, the processing unit 81a1 wakes up the second processor 81b. That is, the processing unit 81a1 supplies power to the second processor 81b from the power supply of the control device 80, and makes the second processor 81b ready to perform its functions. This allows the second processor 81b to perform the functions of the control unit 81b1 and the communication unit 81b2.

[0056] Next, in step S104, the control unit 81b1 temporarily executes a voltage determination to determine whether the voltage V is equal to or lower than the threshold value Vth.

[0057] If it is determined that the voltage V is equal to or less than the threshold value Vth (YES in step S104), the process proceeds to step S105. On the other hand, if it is determined that the voltage V is higher than the threshold value Vth (NO in step S104), the process proceeds to step S107.

[0058] As described above, the timing of the initial voltage determination is determined to be the timing when the voltage V is expected to fall below the threshold value Vth. Therefore, if the change in the voltage V does not deviate significantly from the expected change, the determination in step S104 is basically YES. If the determination in step S104 is YES, the control unit 81b1 executes charging control in step S105.

[0059] In step S105, the control unit 81b1, in the charging control, controls the operation of the DCDC converter 40 to charge the auxiliary battery 50. Specifically, in the charging control, the control unit 81b1 supplies power from the main battery 10 to the auxiliary battery 50 via the DCDC converter 40. As a result, the auxiliary battery 50 is charged.

[0060] During the charging control, the control unit 81b1 charges the auxiliary battery 50 for, for example, a predetermined time. The control unit 81b1 then terminates the charging control when the above-mentioned time has elapsed since the start of the charging control. However, if the remaining capacity of the auxiliary battery 50 reaches a target remaining capacity, the control unit 81b1 may terminate the charging control before the above-mentioned time has elapsed since the start of the charging control. The target remaining capacity is, for example, set in advance by the driver of the vehicle 1.

[0061] Next, in step S106, the communication unit 81b2 executes a notification to the driver of the vehicle 1, who is the user, and the control flow shown in FIG. 4 ends.

[0062] In step S106, the communication unit 81b2 outputs information regarding the operation state of the auxiliary device 60 and notifies the driver of the vehicle 1. For example, the communication unit 81b2 transmits the information regarding the operation state of the auxiliary device 60 to an information processing terminal such as a smartphone carried by the driver of the vehicle 1 and causes the information processing terminal to display the information. Information regarding the operation state of the auxiliary device 60 notified to the driver includes, for example, information indicating the type of auxiliary device 60 that is operating. By outputting such information, it is possible to urge the driver to return to the vehicle 1 and stop the operation of the auxiliary device 60.

[0063] As described above, the timing of the first voltage determination is determined to be the timing when the voltage V is expected to fall below the threshold value Vth. However, if the transition of the voltage V deviates significantly from the expected transition, the determination in step S104 may be NO. If the determination in step S104 is NO, the processing unit 81a1 determines the timing of the next voltage determination in step S107. Note that if the determination in step S104 is NO, the processing unit 81a1 stops the supply of power from the power supply of the control device 80 to the second processor 81b.

[0064] 6 is a flowchart showing an example of the flow of the process for determining the next determination timing performed by the control device 80. The control flow shown in FIG. 6 is executed in step S107 in the control flow shown in FIG.

[0065] When the control flow shown in FIG. 6 starts, first, in step S301, the processing unit 81a1 identifies the actual value of the rate of decrease of the voltage V.

[0066] As will be described later, steps S107 and S108 in Fig. 4 are repeated while the determination in step S104 in Fig. 4 continues to be NO. For example, if the most recent voltage determination is the initial voltage determination, in step S301, the processing unit 81a1 divides the difference between the voltage V when the ignition was turned off and the voltage V at the time of the initial voltage determination by the time between the timing when the ignition was turned off and the timing of the initial voltage determination. The processing unit 81a1 then identifies the value obtained in this manner as the actual value of the rate of decrease of the voltage V.

[0067] Furthermore, for example, if the most recent voltage determination is the second or subsequent voltage determination, in step S301, the processing unit 81a1 divides the difference between the voltage V at the voltage determination immediately before the most recent voltage determination and the voltage V at the most recent voltage determination by the time between the voltage determination immediately before the most recent voltage determination and the voltage determination immediately before the most recent voltage determination. The processing unit 81a1 then identifies the value thus obtained as the actual value of the rate of decrease of the voltage V.

[0068] Next, in step S302, the processing unit 81a1 determines whether the actual value of the rate of decrease of the voltage V is equal to or greater than the estimated value of the rate of decrease of the voltage V. Note that the processing unit 81a1 can use, for example, the estimated value of the rate of decrease of the voltage V estimated in step S201 of FIG. 5 as the estimated value of the rate of decrease of the voltage V in step S302.

[0069] If it is determined that the actual rate of decrease of the voltage V is equal to or greater than the estimated rate of decrease of the voltage V (YES in step S302), the process proceeds to step S303. On the other hand, if it is determined that the estimated rate of decrease of the voltage V is greater than the actual rate of decrease of the voltage V (NO in step S302), the process proceeds to step S304.

[0070] If the determination in step S302 is YES, in step S303, the processing unit 81a1 determines the determination timing for the next voltage determination based on the voltage V at the time of the most recent voltage determination and the actual value of the rate of decrease of the voltage V, and the control flow shown in Figure 6 ends.

[0071] In step S303, the processing unit 81a1 determines, for example, the timing at which the voltage V is expected to fall below the threshold Vth as the timing for the next voltage determination. For example, the processing unit 81a1 divides the difference between the voltage V at the most recent voltage determination and the threshold Vth by the actual value of the rate of decrease of the voltage V identified in step S301. The value obtained in this manner corresponds to the time from the timing of the most recent voltage determination to the timing at which the voltage V is expected to fall below the threshold Vth. The processing unit 81a1 then determines, as the timing for the next voltage determination, the timing at which this time has elapsed since the timing of the most recent voltage determination.

[0072] If the result of the judgment in step S302 is NO, in step S304, the processing unit 81a1 determines the judgment timing for the next voltage judgment based on the voltage V at the time of the most recent voltage judgment and the estimated value of the rate of decrease of the voltage V, and the control flow shown in Figure 6 ends.

[0073] In step S304, as in step S303, the processing unit 81a1 determines, for example, the timing at which the voltage V is expected to fall below the threshold Vth as the timing for the next voltage determination. For example, the processing unit 81a1 divides the difference between the voltage V at the most recent voltage determination and the threshold Vth by the estimated value of the rate of decrease of the voltage V estimated in step S201. The value obtained in this manner corresponds to the time from the most recent voltage determination to the timing at which the voltage V is expected to fall below the threshold Vth. Then, the processing unit 81a1 determines the timing at which this time has elapsed since the most recent voltage determination as the timing for the next voltage determination.

[0074] After step S107 in FIG. 4, in step S108, the processing unit 81a1 determines whether or not it is time to perform the next voltage determination.

[0075] If it is determined that the next voltage determination timing has not yet arrived (NO in step S108), step S108 is repeated. On the other hand, if it is determined that the next voltage determination timing has arrived (YES in step S108), the process returns to step S103.

[0076] As described above, in the control device 80 according to this embodiment, when the ignition of the vehicle 1 is off, the control unit 81b1 temporarily performs a voltage determination to determine whether the voltage V of the auxiliary battery 50 is equal to or lower than the threshold value Vth, and if the voltage determination determines that the voltage V is equal to or lower than the threshold value Vth, the control unit 81b1 performs charging control to charge the auxiliary battery 50. Here, the processing unit 81a1 determines the timing at which the voltage determination is performed based on the operating state of the accessories 60.

[0077] This allows the timing for waking up the second processor 81b to perform the voltage determination to be changed depending on the operating state of the auxiliary device 60. Therefore, the voltage determination can be performed at a timing close to the timing when the voltage V of the auxiliary battery 50 falls below the threshold Vth. Therefore, even if the ignition of the vehicle 1 is turned off while the auxiliary device 60 is operating, it is possible to prevent the auxiliary battery 50 from running out of power.

[0078] Furthermore, by being able to change the timing at which the second processor 81b is woken up and voltage determination is performed depending on the operating state of the auxiliary equipment 60, voltage determination is not performed unnecessarily at an excessively high frequency, and unnecessary power consumption associated with waking up the second processor 81b can also be suppressed.

[0079] The above describes examples of the processing performed by the control device 80 with reference to the flowcharts of Figures 4 to 6. However, the processing performed by the control device 80 is not limited to the above examples.

[0080] 5, the processing unit 81a1 determines the timing at which the voltage V is expected to fall below the threshold value Vth as the determination timing for the initial voltage determination. However, the processing unit 81a1 may determine the timing at which the voltage V is expected to fall below the threshold value Vth as the determination timing for the initial voltage determination to be earlier or later than the timing at which the voltage V is expected to fall below the threshold value Vth.

[0081] 6, the processing unit 81a1 may determine the timing of the next voltage determination as the timing at which the voltage V is expected to fall below the threshold value Vth. However, the processing unit 81a1 may determine the timing of the next voltage determination as a timing earlier or later than the timing at which the voltage V is expected to fall below the threshold value Vth. Furthermore, the processing unit 81a1 may determine the timing of the next voltage determination as the timing at which a predetermined time has elapsed since the timing of the most recent voltage determination, without taking into account the rate at which the voltage V decreases.

[0082] Also, for example, in the above description, the vehicle 1 is an electric vehicle equipped with the traction motor 30 as a drive source. However, the vehicle 1 may also be a hybrid vehicle equipped with an engine as a drive source in addition to the traction motor 30. In this case, the control unit 81b1 supplies power from the main battery 10 to the auxiliary battery 50 via the DCDC converter 40 in the charging control, as in the above example. The vehicle 1 may also be an engine vehicle equipped with an engine as a drive source instead of the traction motor 30. In this case, the control unit 81b1 drives an alternator mounted on the vehicle 1 in the charging control, and supplies power generated by the alternator to the auxiliary battery 50. This allows the auxiliary battery 50 to be charged.

[0083] <Effects of the Control Device> Next, the effects of the control device 80 according to the embodiment of the present invention will be described.

[0084] The processor 81 of the control device 80 according to this embodiment executes processing including temporarily executing a voltage determination to determine whether the voltage V of the auxiliary battery 50 is equal to or lower than a threshold value Vth when the ignition of the vehicle 1 is turned off; executing charge control to charge the auxiliary battery 50 when the voltage determination determines that the voltage V is equal to or lower than the threshold value Vth; and determining the timing of the determination to execute the voltage determination based on the operating state of the auxiliary device 60. This allows the timing of the execution of the voltage determination to be changed depending on the operating state of the auxiliary device 60. Therefore, the voltage determination can be executed at a timing close to the timing when the voltage V of the auxiliary battery 50 falls below the threshold value Vth. Therefore, even if the ignition of the vehicle 1 is turned off while the auxiliary device 60 is operating, depletion of power from the auxiliary battery 50 can be suppressed. Furthermore, by being able to change the timing of the execution of the voltage determination depending on the operating state of the auxiliary device 60, unnecessary execution of the voltage determination at an excessively high frequency and unnecessary power consumption associated with the voltage determination can be suppressed.

[0085] Furthermore, the processor 81 of the control device 80 according to the present embodiment preferably executes processing including estimating the rate of decrease of the voltage V based on the operating state of the auxiliary device 60, and determining the timing of the initial voltage determination after the ignition is turned off based on the voltage V at the time the ignition is turned off and the estimated value of the rate of decrease of the voltage V. This makes it possible to accurately estimate the rate of decrease of the voltage V, which may vary depending on the operating state of the auxiliary device 60, taking into account the operating state of the auxiliary device 60, and then determine the timing of the initial voltage determination. Therefore, the initial voltage determination can be performed close to the timing when the voltage V of the auxiliary battery 50 falls below the threshold Vth.

[0086] Furthermore, the processor 81 of the control device 80 according to this embodiment preferably executes processing that includes estimating the rate of decrease in the voltage V based on the temperature of the auxiliary battery 50 in addition to the operating state of the auxiliary device 60. This allows the rate of decrease in the voltage V to be more accurately estimated taking into account the temperature of the auxiliary battery 50. This makes it possible to more appropriately execute the initial voltage determination at a timing close to the timing when the voltage V of the auxiliary battery 50 falls below the threshold Vth.

[0087] Furthermore, the processor 81 of the control device 80 according to this embodiment preferably executes processing that includes estimating the rate of decrease in the voltage V based on the degree of deterioration of the auxiliary battery 50 in addition to the operating state of the auxiliary device 60. This allows the rate of decrease in the voltage V to be more accurately estimated taking into account the degree of deterioration of the auxiliary battery 50. This makes it possible to more appropriately execute the initial voltage determination at a timing close to the timing when the voltage V of the auxiliary battery 50 falls below the threshold Vth.

[0088] Furthermore, when the voltage determination determines that the voltage V is higher than the threshold Vth, the processor 81 of the control device 80 according to this embodiment preferably does not execute charge control but executes processing including determining the timing of the next voltage determination. This allows the processor 81 to execute the voltage determination again when the voltage V of the auxiliary battery 50 deviates significantly from the expected transition, and to execute charge control when the voltage V of the auxiliary battery 50 falls below the threshold Vth.

[0089] Furthermore, when the voltage V is determined to be higher than the threshold value Vth in the voltage determination, the processor 81 of the control device 80 according to this embodiment preferably executes processing including: identifying an actual value of the rate of decrease of the voltage V after the ignition is turned off; and determining the timing of the next voltage determination based on the voltage V at the time of the voltage determination and the actual value of the rate of decrease of the voltage V. This allows the rate of decrease of the voltage V to be accurately determined in consideration of the actual change in the voltage V, and then determines the timing of the next voltage determination. Therefore, the next voltage determination can be performed at a timing close to the timing when the voltage V of the auxiliary battery 50 falls below the threshold value Vth.

[0090] Furthermore, when the voltage V is determined to be higher than the threshold Vth in the voltage determination, and the estimated value of the rate of decline of the voltage V is greater than the actual value of the rate of decline of the voltage V, the processor 81 of the control device 80 according to this embodiment preferably executes processing that includes determining the timing of the next voltage determination based on the voltage V at the time of the voltage determination and the estimated value of the rate of decline of the voltage V. This allows the timing of the next voltage determination to be earlier than when the timing is determined based on the actual value of the rate of decline of the voltage V. Therefore, charging control can be performed more reliably before the voltage of the auxiliary battery 50 is depleted.

[0091] Furthermore, when it is determined in the voltage determination that the voltage V is equal to or lower than the threshold value Vth, the processor 81 of the control device 80 according to this embodiment preferably executes processing that includes outputting information regarding the operating state of the auxiliary device 60. This makes it possible, for example, to notify the driver of the vehicle 1 that the auxiliary device 60 is operating in the parked vehicle 1 and urge the driver to return to the vehicle 1 and stop the operation of the auxiliary device 60.

[0092] Furthermore, the vehicle 1 according to this embodiment includes a traction motor 30, a main battery 10 that stores power supplied to the traction motor 30, and a voltage conversion device provided between the main battery 10 and the auxiliary battery 50, and the processor 81 preferably executes processing in the charge control that includes supplying power from the main battery 10 to the auxiliary battery 50 via the voltage conversion device. This allows the auxiliary battery 50 to be appropriately charged by the charge control. In the above example, the DC-DC converter 40 corresponds to the voltage conversion device.

[0093] The above describes a preferred embodiment of the present invention with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the above-described embodiment, and various modified or altered examples within the scope of the claims also fall within the technical scope of the present invention.

[0094] For example, the processes described herein using flowcharts do not necessarily have to be performed in the order shown in the flowcharts, and additional process steps may be employed or some process steps may be omitted.

[0095] REFERENCE SIGNS LIST 1 vehicle 10 main battery 20 inverter 30 traction motor 40 DCDC converter (voltage conversion device) 50 auxiliary battery 60 auxiliary device 71 ignition sensor 72 voltage sensor 73 temperature sensor 80 control device 81 processor 81a first processor 81a1 processing unit 81b second processor 81b1 control unit 81b2 communication unit 82 memory T time V voltage Vth threshold value W drive wheel

Claims

1. Auxiliary equipment and An auxiliary battery that stores the power supplied to the aforementioned auxiliary equipment, A vehicle control device equipped with, The control device is One or more processors, One or more memories connected to the one or more processors, It has, The aforementioned processor, With the ignition of the vehicle turned off, a voltage check is temporarily performed to determine whether the voltage of the auxiliary battery is below a threshold, If the voltage determination determines that the voltage is below the threshold, the charging control is performed to charge the auxiliary battery. Based on the operating status of the auxiliary equipment, the timing at which the voltage determination is performed is determined. Execute the process that includes Control device.

2. The aforementioned processor, Based on the operating state of the auxiliary equipment, the rate of voltage decrease is estimated, Based on the voltage at the time the ignition is turned off and an estimated value of the rate at which the voltage decreases, the timing of the first voltage determination after the ignition is turned off is determined. Execute the process that includes The control device according to claim 1.

3. The processor performs a process that includes estimating the rate of voltage decrease based on the operating state of the auxiliary equipment and the temperature of the auxiliary equipment battery. The control device according to claim 2.

4. The processor performs a process that includes estimating the rate of voltage decrease based on the operating state of the auxiliary equipment and the degree of degradation of the auxiliary battery. The control device according to claim 2 or 3.

5. If the voltage determination is found to be higher than the threshold, the processor performs a process that includes determining the timing of the next voltage determination without executing the charging control. The control device according to claim 1.

6. When the voltage determination is found to be higher than the threshold, the processor To determine the actual value of the rate of voltage decrease after the ignition is turned off, Based on the voltage at the time of the voltage determination and the actual value of the rate at which the voltage decreases, the timing of the next voltage determination is determined. Execute the process that includes The control device according to claim 5.

7. If the voltage is determined to be higher than the threshold in the voltage determination, and the estimated rate of voltage decrease is greater than the actual rate of voltage decrease, the processor performs a process that includes determining the timing of the next voltage determination based on the voltage at the time of the voltage determination and the estimated rate of voltage decrease. The control device according to claim 6.

8. The processor, when it is determined in the voltage determination that the voltage is below the threshold, performs a process that includes outputting information regarding the operating state of the auxiliary equipment. The control device according to claim 1.

9. The aforementioned vehicle is The driving motor and A main battery that stores the power supplied to the aforementioned drive motor, A voltage converter is provided between the main battery and the auxiliary battery, Equipped with, The processor, in the charge control, performs a process that includes supplying power from the main battery to the auxiliary battery via the voltage converter. The control device according to claim 1.