Power supply control device, power supply control method, and power supply control program

Abstract

To suppress reduction of convenience for a user due to diagnosis of a backup power supply.SOLUTION: A power supply control device according to an embodiment comprises a controller that performs diagnosis of a deterioration level on a backup power supply that supplies electric power to a load of a vehicle when a main power supply supplying electric power to the load fails. The controller starts a diagnosis before a user rides on the vehicle if occurrence of an event indicating that the user is to ride on the vehicle is detected.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The disclosed embodiments relate to a power supply control device, a power supply control method, and a power supply control program. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a power supply control device having a backup power supply for backup use in the event that a main power supply fails is known (see, for example, Patent Document 1).

[0003] Patent Document 1 describes a method of diagnosing whether a backup power supply used for automatic driving of a vehicle functions correctly when the vehicle is started (when the IG is turned on). Specifically, Patent Document 1 describes a method of discharging or charging the backup power supply at startup to calculate the internal resistance of the backup power supply and determine the degree of deterioration, and enables automatic driving if there is no problem with the deterioration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-3696 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional technology has a problem in that the diagnosis of the backup power supply may reduce user convenience.

[0006] For example, in the technology described in Patent Document 1, it takes time for the diagnosis to finish after the vehicle is started, so the user may not be able to start autonomous driving immediately after getting in the vehicle.

[0007] Furthermore, the target that receives the power supply from the backup power supply is not limited to an autonomous driving system, but may be, for example, a steer-by-wire system that controls the steering angle with a motor. Also, it is desirable to prohibit a vehicle equipped with a steer-by-wire system from traveling if the backup power supply does not function properly. Therefore, the steer-by-wire system cannot be used until the diagnosis of the backup power supply is completed after the vehicle is started, and the vehicle cannot travel, which reduces user convenience.

[0008] The present invention has been made in view of the above, and has an object to prevent a decrease in user convenience due to diagnosis of a backup power supply. [Means for solving the problem]

[0009] According to an embodiment of the present invention, a power supply control device includes a controller that diagnoses a degree of deterioration of a backup power supply that supplies power to a load in a vehicle when a main power supply that supplies power to the load fails. When the controller detects the occurrence of an event indicating that a user will get into the vehicle, the controller starts the diagnosis before the user gets into the vehicle. Effect of the Invention

[0010] According to one aspect of the embodiment, it is possible to prevent a decrease in user convenience due to diagnosis of a backup power supply. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of a power supply control device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Diagram 3] FIG. 3 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Diagram 5]FIG. 5 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 6] FIG. 6 is a timing chart showing the timing of the diagnostic process according to the embodiment. [Figure 7] FIG. 7 is a diagram showing an example of a cell resistance value map according to the embodiment. [Figure 8] FIG. 8 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 9] FIG. 9 is an explanatory diagram illustrating an example of the operation of the power supply control device according to the embodiment. [Figure 10] FIG. 10 is a flowchart illustrating an example of a process executed by the power supply control device according to the embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of deterioration diagnosis due to discharge according to the embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of deterioration diagnosis by charging according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of a power supply control device, a power supply control method, and a power supply control program will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. Below, a power supply control device that is mounted on a vehicle with an automatic driving function and supplies power to a load will be described as an example, but the power supply control device according to the embodiment may be mounted on a vehicle that does not have an automatic driving function.

[0013] Further, although the following description will be given of a case where the vehicle in which the power supply control device is installed is an electric vehicle or a hybrid vehicle, the vehicle in which the power supply control device is installed may also be an engine vehicle that is run by an internal combustion engine.

[0014] In addition, the power supply control device according to the embodiment may be installed in any device that has a main power supply and a backup power supply (auxiliary power supply) and that backs up the main power supply with the backup power supply in the event of a power failure in the main power supply.

[0015] [1. Power supply control device configuration] FIG. 1 is an explanatory diagram showing an example of the configuration of a power supply control device according to an embodiment. A power supply ECU (Electronic Control Unit) 20 is an example of a power supply control device. As shown in FIG. 1, the power supply ECU 20 according to the embodiment is connected to a main power supply 10, a first system load 30, a general load 40, a second system load 50, an automatic driving control ECU 60, a door lock control ECU 70, and a steer-by-wire ECU 80. The power supply ECU 20 includes a first system 110 that supplies power from the main power supply 10 to the first system load 30 and the general load 40, and a second system 120 that supplies power from a backup power supply 22 (described later) to the second system load 50.

[0016] The first load system 30 includes one or more loads. The first load system 30 includes at least a steering motor 31 for implementing steer-by-wire. In addition, the first load system 30 includes loads necessary for automatic driving control, i.e., devices that operate during automatic driving, such as an electric brake device, an in-vehicle camera, and a radar. The general load 40 includes loads that are not directly involved in automatic driving control, such as a display, an air conditioner, an audio device, a video device, and various lights.

[0017] The second load system 50 has the same functions as the first load system 30. The second load system 50 includes at least a steering motor 51 for implementing steer-by-wire. In addition, the second load system 50 includes loads necessary for automatic driving control, such as an electric brake device, an in-vehicle camera, and a radar, i.e., devices that operate during automatic driving. The first load system 30, the general load 40, and the second load system 50 operate using power supplied from the power supply ECU 20.

[0018] The automatic driving control ECU 60 is a device that operates the first load system 30 or the second load system 50 to perform automatic driving control of the vehicle.

[0019] The door lock control ECU 70 is an ECU that controls the door lock of the vehicle. The door lock control ECU 70 communicates with a key equipped with a wireless communication function, and locks and unlocks the vehicle doors in response to a signal received from the key. When the key is within a certain range from the vehicle, the vehicle can receive a radio signal output from the key. The door lock control ECU 70 locks and unlocks the vehicle doors in response to the radio signal received from the key. The key may be a dedicated device for operating the vehicle door lock, or may be an information processing terminal such as a smartphone equipped with a radio transmission and reception function.

[0020] The steer-by-wire ECU 80 controls the steering motor 31 or the steering motor 51 in response to a steering operation by a user. In this way, the steer-by-wire ECU 80 realizes the steer-by-wire.

[0021] The main power supply 10 includes a DC / DC converter (hereinafter, referred to as "DC / DC 11") and a lead battery (hereinafter, referred to as "PbB 12"). Note that the battery of the main power supply 10 may be any secondary battery other than the PbB 12.

[0022] The DC / DC 11 is connected to a generator and a high-voltage battery having a higher voltage than the PbB 12, and steps down the voltages of the generator and the high-voltage battery and outputs the stepped-down voltage to the first system 110. The generator is, for example, an alternator that converts the kinetic energy of a traveling vehicle into electricity to generate power. The high-voltage battery is, for example, a battery for driving the vehicle that is mounted on an electric vehicle or a hybrid vehicle.

[0023] When the main power supply 10 is installed in an engine vehicle, it is equipped with an alternator (generator) instead of the DC / DC 11. The DC / DC 11 charges the PbB 12, supplies power to the first load 30 and the general load 40, supplies power to the second load 50, and charges the backup power supply 22 described later.

[0024] The power supply ECU 20 includes a backup power supply 22, a system switch 253, a battery switch 251, a bypass switch 252, a microcomputer 21, a first voltage sensor 231, a second voltage sensor 232, and a DC / DC 241. The backup power supply 22 is a backup power supply in case the main power supply 10 is unable to supply power during autonomous driving. The backup power supply 22 supplies power to a load in the vehicle when the main power supply 10 that supplies power to the load fails. The backup power supply 22 includes a lithium ion battery (hereinafter referred to as "LiB 221"). The battery of the backup power supply 22 may be any secondary battery other than the LiB 221.

[0025] The inter-system switch 253 is provided on an inter-system line connecting the first system 110 and the second system 120, and is a switch capable of connecting and disconnecting the first system 110 and the second system 120. The battery switch 251 is a switch capable of connecting and disconnecting the LiB 221 to the second system 120. Specifically, the battery switch 251 is a switch capable of connecting and disconnecting the LiB 221 to the bypass switch 252 and the DC / DC 241.

[0026] The bypass switch 252 is a switch that can connect and disconnect the battery switch 251 and the second system 120. The DC / DC 241 is connected in parallel with the bypass switch 252, and adjusts the voltage output from the LiB 221 and the voltage input to the LiB 221.

[0027] The first voltage sensor 231 is provided in the first system 110, detects the voltage of the first system 110, and outputs the detection result to the microcomputer 21. The second voltage sensor 232 is provided in the second system 120, detects the voltage of the second system 120, and outputs the detection result to the microcomputer 21.

[0028] The microcomputer 21 includes a processor such as a CPU (Central Processing Unit) and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The microcomputer 21 may be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The microcomputer 21 is an example of a controller.

[0029] The microcomputer 21 controls the operation of the power supply ECU 20 by causing the CPU to execute a program stored in the ROM using the RAM as a working area. The microcomputer 21 detects a ground fault in the first system 110 or the second system 120 based on the detection results input from the first voltage sensor 231 and the second voltage sensor 232. A specific example of a method for detecting a ground fault by the microcomputer 21 will be described later.

[0030] When the microcomputer 21 detects a ground fault in the first system 110 or the second system 120, it notifies each ECU of that fact. When the microcomputer 21 detects a ground fault in the first system 110 or the second system 120, it may notify the automatic driving control ECU 60 of the fact that automatic driving is impossible. When the microcomputer 21 does not detect a ground fault in the first system 110 or the second system 120, it may notify the automatic driving control ECU 60 of the fact that automatic driving is possible.

[0031] Furthermore, when the microcomputer 21 detects a ground fault in the first system 110 or the second system 120, it may notify the steer-by-wire ECU 80 that steer-by-wire is not possible. Furthermore, when the microcomputer 21 does not detect a ground fault in the first system 110 or the second system 120, it may notify the steer-by-wire ECU 80 that steer-by-wire is possible.

[0032] When a power failure such as a ground fault occurs in the first system 110, the microcomputer 21 cuts off the system-to-system switch 253, and turns on the battery switch 251 and the bypass switch 252 to supply power from the backup power source 22 to the second system load 50. When a power failure such as a ground fault occurs in the second system 120, the microcomputer 21 cuts off the system-to-system switch 253, and supplies power from the main power source 10 to the first system load 30 and the general load 40 with the battery switch 251 cut off.

[0033] As a result, even if a ground fault occurs in one of the systems during driving, the power supply ECU 20 can use the other system and have the automatic driving control ECU 60 evacuate the vehicle to a safe place and stop the vehicle.

[0034] Furthermore, the microcomputer 21 can discharge the backup power supply 22 to calculate the internal resistance (hereinafter referred to as “cell resistance”) value of the backup power supply 22, and determine the deterioration of the cell resistance of the backup power supply 22 based on the cell resistance value.

[0035] Furthermore, when the SOC (State Of Charge), which is a value indicating the charging state of the backup power supply 22, falls below a recharge threshold, the microcomputer 21 charges the backup power supply 22 to calculate the capacity deterioration rate of the backup power supply 22, and can determine the deterioration of the capacity of the backup power supply 22 based on the capacity deterioration rate.

[0036] The microcomputer 21 diagnoses whether or not the backup power supply 22 can back up the main power supply 10, based on the determination result of the deterioration of the capacity of the backup power supply 22. In this way, the power supply ECU 20 can accurately diagnose whether or not the backup power supply 22 can back up the main power supply 10, by taking into account the deterioration of the cell resistance of the backup power supply 22 and the deterioration of the capacity of the backup power supply 22. An example of the operation of the microcomputer 21 will be described later with reference to Figures 2 to 5 and 8 to 9.

[0037] The microcomputer 21 stores information in an information storage device such as a data flash. The microcomputer 21 stores a cell resistance value map and a previous capacity deterioration rate. An example of the cell resistance value map will be described later with reference to Fig. 8. Next, the operation of the power supply ECU 20 will be described with reference to Figs. 2 to 9.

[0038] [2. Timing of backup power diagnosis] First, the timing of diagnosis of the backup power supply will be described. When the microcomputer 21 detects the occurrence of an event indicating that the user will get into the vehicle, it starts the diagnosis before the user gets into the vehicle. Since the diagnosis starts before the user gets into the vehicle, the diagnosis is completed, for example, by the time the vehicle is started (the IG is turned on). This allows the user to start the vehicle without waiting for the diagnosis of the backup power supply 22 to finish. As a result, a decrease in user convenience due to the diagnosis of the backup power supply 22 is suppressed.

[0039] The phenomenon may be referred to as an event. Moreover, the occurrence of an event indicating that a user gets into a vehicle is called a trigger. That is, the microcomputer 21 detects a trigger. The microcomputer 21 can detect a trigger based on signals input from various ECUs such as the automatic driving control ECU and the door lock control ECU 70. Moreover, the microcomputer 21 may detect a trigger when sensor values ​​acquired from various sensors provided in the vehicle satisfy a condition. Specific examples of triggers will be described below.

[0040] The microcomputer 21 can detect that the user has approached within a certain range from the vehicle as a trigger. For example, the microcomputer 21 detects that the user has approached within a certain range from the vehicle when the distance between the key for unlocking the vehicle door and the vehicle becomes less than a threshold value.

[0041] For example, when the door lock control ECU 70 receives a radio signal output from a key, it transmits a signal indicating that the key is approaching within a certain range from the vehicle to the microcomputer 21. When the microcomputer 21 receives a signal from the door lock control ECU 70, it assumes that a user carrying the key is approaching and detects a trigger.

[0042] A user approaching the vehicle may perform operations such as unlocking the door, opening the door, getting in the vehicle, and then turning on the IG. If the diagnosis of backup power supply 22 is completed while the user is performing these operations, the user can start the vehicle without waiting.

[0043] The microcomputer 21 may detect the trigger when it detects that the vehicle door is unlocked. In this case, the door lock control ECU 70 transmits a signal indicating that the door is unlocked to the microcomputer 21. When the microcomputer 21 receives the signal from the door lock control ECU 70, it detects the trigger. Note that the door may be unlocked by a radio signal from a key, by the user operating a button or the like provided on the vehicle, or by the user inserting the key into the keyhole.

[0044] When detecting the unlocking of the vehicle door as a trigger, the influence of radio wave reception conditions, etc. is reduced compared to when the trigger is the user approaching within a certain range of the vehicle, so the microcontroller 21 can detect the trigger more reliably.

[0045] Furthermore, the microcomputer 21 may obtain the time when the user reserves use of the vehicle, and may detect, as a trigger, that a certain amount of time has passed since the reserved use time.

[0046] Here, it is assumed that the vehicle is used in a service such as car sharing or rental car. In this case, the vehicle is used by a user who has specified a reservation time for use in advance. For example, the reservation time for use is stored in a server or the like via a reservation system.

[0047] The microcomputer 21 obtains the reserved use time from the server via a communication ECU provided in the vehicle. Alternatively, the microcomputer 21 may obtain the reserved use time by manual input by an administrator.

[0048] Then, the microcomputer 21 detects the trigger when the time is a certain time before the reserved use time (for example, 5 minutes before the reserved use time). As a result, the diagnosis ends at the reserved use time, and the user can start the vehicle without waiting. If the vehicle is equipped with a control device that manages the reserved use of the vehicle, the trigger may be detected from the control device.

[0049] The microcontroller 21 may detect, as a trigger, that a certain amount of time has passed before the predicted time at which the user will start driving the vehicle, which is predicted based on the history of the time at which the user starts driving the vehicle.

[0050] The microcomputer 21 accumulates the time when the IG was turned on as a history of the time when the user started driving. The microcomputer 21 predicts the next time when the IG will be turned on based on the history for a certain period of time in the past (for example, one week).

[0051] For example, the history of the times when the IG was turned on for one week is "8:03, 7:56, 8:08, 8:01, 8:00, 7:54, 8:01." In this case, since the average of each time is "8:00," the microcomputer 21 detects a trigger when the time is 5 minutes before "8:00," that is, "7:55." As a result, the diagnosis is completed by "8:00," and the user can start the vehicle without waiting after "8:00."

[0052] The microcomputer 21 may detect the trigger when the time reaches "7:49", i.e., five minutes before "7:54", which is the earliest time in the history. This makes it possible to more reliably prevent the user from having to wait. Furthermore, if there is a specific time that is significantly different from the other times among the times when the IG is turned on in a week (for example, most of the times are around 8:00, but one time is 12:00), the microcomputer 21 may predict the next time when the IG will be turned on excluding the specific time.

[0053] [3. Normal operation of the power supply control device] Under normal circumstances when no ground fault has occurred in the first system 110 and the second system 120, the microcontroller 21 turns off the battery switch 251, turns on the inter-system switch 253 while keeping the bypass switch 252 conductive, as shown in FIG. 2, and supplies power from the main power source 10 to the first system load 30, the general load 40, and the second system load 50.

[0054] [4. Operation of power supply control device when a ground fault occurs] Next, the operation of the power supply ECU 20 when a ground fault occurs will be described with reference to Figures 3 to 5. As shown in Figure 3, in the power supply ECU 20, for example, when a ground fault 271 occurs in the first system 110, an overcurrent flows toward the ground fault point, and the voltage of the first system 110 detected by the first voltage sensor 231 becomes equal to or lower than the ground fault threshold value.

[0055] Furthermore, in the power supply ECU 20, when a ground fault 272 occurs in the second system 120, an overcurrent flows toward the ground fault point, and the voltage of the second system 120 detected by the second voltage sensor 232 becomes equal to or lower than the ground fault threshold value.

[0056] Therefore, when the voltage detected by at least one of the first voltage sensor 231 and the second voltage sensor 232 becomes equal to or lower than the ground fault threshold, the microcomputer 21 detects an abnormality in the power supply, cuts off the inter-system switch 253, and turns on the battery switch 251. At this time, the microcomputer 21 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120. Regardless of whether a ground fault has occurred in the first system 110 or the second system 120, the detected voltages of the first voltage sensor 231 and the second voltage sensor 232 show the same decreasing tendency. Therefore, the microcomputer 21 may determine a ground fault by comparing the detected voltage of either the first voltage sensor 231 or the second voltage sensor 232 with the ground fault threshold.

[0057] By cutting off inter-system switch 253 and turning on battery switch 251, the voltage of the system where no ground fault has occurred returns to a normal state, while the voltage of the system where a ground fault has occurred continues to drop.

[0058] Then, if the voltage detected by the first voltage sensor 231 remains below the ground fault threshold for a predetermined time or more and the voltage detected by the second voltage sensor 232 returns to exceed the ground fault threshold within the predetermined time, the microcontroller 21 determines that a ground fault 271 has occurred in the first system 110.

[0059] 4, the microcomputer 21 supplies power from the backup power supply 22 to the second load 50 and notifies the autonomous driving control ECU 60 of this fact. As a result, the autonomous driving control ECU 60 operates the second load 50 using the power supplied from the backup power supply 22, and can evacuate the vehicle to a safe place and stop the vehicle.

[0060] In addition, after the microcontroller 21 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120, if the voltage detected by the second voltage sensor 232 is below the ground fault threshold and the voltage detected by the first voltage sensor 231 returns to exceed the ground fault threshold within a predetermined time, the microcontroller 21 finally determines that a ground fault 272 has occurred in the second system 120.

[0061] 5, the microcomputer 21 turns off the battery switch 251, supplies power from the main power supply 10 to the first load 30, and notifies the automatic driving control ECU 60 of this fact. As a result, the automatic driving control ECU 60 can operate the first load 30 using the power supplied from the main power supply 10, and drive the vehicle to a safe place and stop the vehicle.

[0062] In addition, in the power supply ECU 20, when the first system load 30, the general load 40 or the second system load 50 temporarily becomes overloaded, rather than when a ground fault 271 or 272 occurs, the voltages detected by the first voltage sensor 231 and the second voltage sensor 232 may temporarily become lower than the ground fault threshold value.

[0063] In this case, in the power supply ECU 20, power is continuously supplied from the main power supply 10 to the first system load 30 and the general load 40, and power is continuously supplied from the backup power supply 22 to the second system load 50. Therefore, if the voltages detected by the first voltage sensor 231 and the second voltage sensor 232 both return to exceed the ground fault threshold before a predetermined time has elapsed after the microcomputer 21 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120, the microcomputer 21 determines that there is no abnormality in the power supply. Thereafter, in order to return to the normal operation shown in FIG. 2, the microcomputer 21 turns off the battery switch 251 and re-opens the system switch 253. Note that the microcomputer 21 may use a return threshold that is larger than the ground fault threshold as the threshold for determining the return, instead of the ground fault threshold. The microcomputer 21 may also determine that there is no abnormality in the power supply when the voltage exceeds the return determination threshold continuously for a predetermined time or more.

[0064] [5. Backup power diagnostic operation] 6 to 9, a description will be given of a diagnostic operation in which microcomputer 21 of power supply ECU 20 diagnoses whether or not backup of main power supply 10 by backup power supply 22 is possible. Here, backup power supply 22 is capable of backing up main power supply 10 if the SOC exceeds a predetermined lower limit value for backup possibility.

[0065] However, if the backup power supply 22 is deteriorated, even if the SOC exceeds the lower limit of the backup possible value, the amount of power that can be supplied is reduced compared to normal times without deterioration, and it may not be able to back up the main power supply 10. Therefore, in order to accurately diagnose whether or not backup is possible, it is necessary to take the deterioration of the backup power supply 22 into consideration.

[0066] One method for determining the deterioration of the backup power supply 22 is a determination method based on the capacity deterioration rate. The capacity deterioration rate can be calculated, for example, by recharging the backup power supply 22 with a low charge level and based on the rate of increase in the charge level of the backup power supply 22 at that time. The capacity deterioration rate can also be calculated by charging the backup power supply 22 with a low charge level until it is fully charged and based on the SOC of the backup power supply 22 at that time.

[0067] Therefore, for example, when the backup power supply 22 naturally discharges and the SOC falls below the recharge threshold, it is possible to recharge the backup power supply 22 and diagnose whether backup is possible or not, taking into consideration the capacity deterioration rate calculated based on the SOC at that time and the rate of increase in the charge amount.

[0068] However, it may take several months for the SOC of the backup power supply 22 to become less than the recharge threshold due to natural discharge. Therefore, for example, if a diagnosis of backup feasibility is performed based on the SOC every time the backup power supply 22 is started, the diagnosis will be performed based on the capacity deterioration rate from up to several months ago, and there is a risk that an accurate diagnosis of the backup power supply 22 cannot be performed.

[0069] Therefore, as shown in FIG. 6, the microcomputer 21 of the power supply ECU 20 according to this embodiment discharges the backup power supply 22 and calculates the cell resistance at the timing when the trigger is detected.

[0070] Then, the microcontroller 21 judges whether the cell resistance has deteriorated, and if it is determined that the cell resistance has not deteriorated, that the capacity has not deteriorated based on the previously calculated capacity deterioration rate, and if the SOC of the backup power supply 22 exceeds the recharge threshold, it diagnoses that backup is possible.

[0071] In this embodiment, the capacity degradation rate when the backup power supply 22 is new is set to 100%, and the value of the capacity degradation rate decreases as the degradation of the capacity progresses. In this way, the microcomputer 21 can accurately diagnose whether or not backup is possible by taking into account the degradation of the cell resistance determined at the time of trigger detection.

[0072] Thereafter, when the SOC of the backup power supply 22 falls below the recharge threshold, the microcomputer 21 charges the backup power supply 22 and calculates the current capacity deterioration rate. The microcomputer 21 then performs a cell resistance deterioration determination, and if the cell resistance has not deteriorated, the capacity has not deteriorated based on the currently calculated capacity deterioration rate, and the SOC of the backup power supply 22 exceeds the recharge threshold, the microcomputer 21 diagnoses that backup is possible. In this way, the microcomputer 21 can accurately diagnose whether backup is possible or not by taking into account the cell resistance deterioration determined at the time of trigger detection and the latest capacity deterioration rate.

[0073] Specifically, when the microcomputer 21 detects a trigger, it first estimates the SOC of the backup power supply 22 and acquires the temperature from the backup power supply 22. Then, the microcomputer 21 estimates an EOL (End Of Life) resistance value of the backup power supply 22 based on the SOC of the backup power supply 22, the temperature of the backup power supply 22, and a cell resistance value map.

[0074] The EOL resistance value is a value exceeding the upper limit of the cell resistance value at which the backup power supply 22 can perform backup, and is the cell resistance value of the backup power supply 22 that has reached the end of its product life. In other words, if the cell resistance value of the backup power supply 22 is less than the EOL resistance value, then the backup power supply 22 is in a state where backup is possible with respect to the cell resistance.

[0075] 6, after the microcomputer 21 detects a trigger, the diagnosis of the backup power supply 22 can be completed before the IG is turned on. For example, the microcomputer 21 detects a trigger at time t11 and starts the diagnosis. Then, the microcomputer 21 ends the diagnosis at time t12. Therefore, when the IG is turned on at time t13 after time t12, the diagnosis will have ended.

[0076] Furthermore, when the SOC of the backup power supply 22 is equal to or lower than the threshold, the microcomputer 21 performs diagnosis by charging the backup power supply 22. For example, at time t41 in Fig. 6, the SOC is equal to or lower than the recharge threshold, so the microcomputer 21 performs diagnosis by charging the backup power supply 22. This allows the microcomputer 21 to perform diagnosis while charging the backup power supply 22. As a result, the efficiency of the entire process is improved.

[0077] However, diagnosis by charging takes longer than diagnosis by discharging. Therefore, the diagnosis may not be completed between the time when the trigger is detected and the time when the IG is turned on by the user. For example, if the diagnosis by charging starts at time t41 in FIG. 6, the diagnosis by charging has not finished at time t42 when the diagnosis by discharging would have finished.

[0078] Therefore, when performing diagnosis by charging, the microcomputer 21 notifies the user that it will take some time until the diagnosis makes the vehicle usable. For example, the microcomputer 21 notifies the user by outputting images and sounds from a display and a speaker mounted on the vehicle, or by turning on a lamp indicating that the diagnosis is in progress.

[0079] Here, an example of the cell resistance value map will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of the cell resistance value map according to the embodiment. As shown in Fig. 7, the cell resistance value map is a map showing the relationship between the SOC and temperature of the backup power supply 22 and the EOL resistance value in that state. The microcomputer 21 obtains the EOL cell resistance value corresponding to the estimated SOC of the backup power supply 22 and the obtained temperature from the cell resistance value map.

[0080] Next, as shown in FIG. 8, while the inter-system switch 253 is cut off, the microcontroller 21 cuts off the bypass switch 252, turns on the battery switch 251, controls the DC / DC 241, and supplies a diagnostic current from the backup power supply 22 to the second system load 50 via the DC / DC 241.

[0081] At this time, the microcomputer 21 adjusts the DC / DC converter 241 so that a current smaller than that during actual backup is applied, thereby enabling the microcomputer 21 to minimize the discharge amount of the backup power supply 22.

[0082] Then, the microcomputer 21 calculates the cell resistance R=ΔV / ΔI from the current ΔI and voltage ΔV discharged from the backup power supply 22 at this time. At this time, the microcomputer 21 can obtain the current ΔI from a current sensor (not shown) provided in the second system 120 or the backup power supply 22, and obtain the voltage ΔV from the second voltage sensor 232.

[0083] If the calculated cell resistance value is less than the EOL cell resistance value at that time, the microcontroller 21 determines that the cell resistance has not deteriorated, and if the cell resistance value is equal to or greater than the EOL cell resistance value at that time, it determines that the cell resistance has deteriorated.

[0084] At this time, if the previous capacity deterioration rate exceeds the EOL deterioration rate (e.g., 80%), the microcontroller 21 determines that the capacity has not deteriorated, and if the previous capacity deterioration rate is equal to or lower than the EOL deterioration rate, it determines that the capacity has deteriorated.

[0085] Then, if the microcomputer 21 determines that the cell resistance has not deteriorated, determines that the capacity has not deteriorated, and the SOC exceeds the recharge threshold, it diagnoses that the main power supply 10 can be backed up by the backup power supply 22. Note that in this diagnosis, the deterioration of the capacity may be omitted as a factor for the determination.

[0086] 9, when the SOC of the backup power supply 22 falls below the recharge threshold, the microcomputer 21 turns on the inter-system switch 253 and supplies power from the main power supply 10 to the backup power supply 22 via the DC / DC converter 241 to charge the backup power supply 22. Then, the microcomputer 21 calculates the capacity deterioration rate of the backup power supply 22.

[0087] At this time, the microcomputer 21 calculates the capacity deterioration rate based on, for example, the rate of increase in the charge amount in the backup power source 22 when charging is performed. Note that the microcomputer 21 may calculate the capacity deterioration rate based on the SOC of the backup power source 22 when charging for a predetermined charging time required for the backup power source 22 to be fully charged is completed.

[0088] Here, the recharge threshold is set to a value larger than the lower limit of the SOC at which the main power supply 10 can be backed up by the backup power supply 22. For example, as shown in Fig. 6, the recharge threshold is set to a value obtained by adding the sensor error / computation error and the maximum discharge amount in 30 days to the lower limit of the SOC at which backup is possible.

[0089] As a result, power supply ECU 20 can guarantee a SOC that allows backup the next time the IG is turned on, if the period from when the IG was last turned off to when the IG is next turned on is within 30 days.

[0090] If the calculated capacity deterioration rate exceeds the EOL deterioration rate (e.g., 80%), the microcontroller 21 determines that the capacity has not deteriorated, and if the calculated capacity deterioration rate is equal to or less than the EOL deterioration rate, it determines that the capacity has deteriorated.

[0091] Here too, the microcomputer 21 determines whether the cell resistance has deteriorated based on the cell resistance value. If the microcomputer 21 determines that the cell resistance has not deteriorated and that the capacity has not deteriorated, it diagnoses that the backup power supply 22 can back up the main power supply 10.

[0092] In this diagnosis, the deterioration of the cell resistance may be omitted from the criteria for judgment. In this way, the power supply ECU 20 can accurately diagnose whether or not backup is possible by taking into account the deterioration of the cell resistance, which is judged every time the power supply ECU 20 starts up, and the capacity deterioration rate.

[0093] Furthermore, since the power supply ECU 20 discharges the backup power supply 22, albeit a small amount, each time the IG is turned on, the SOC of the backup power supply 22 falls to the recharge threshold value earlier than it falls below the recharge threshold value due to natural discharge.

[0094] As a result, the power supply ECU 20 increases the frequency with which it calculates the period at which the backup power supply 22 is recharged, i.e., the capacity deterioration rate of the backup power supply 22, thereby improving the reliability of the capacity deterioration determination result based on the capacity deterioration rate.

[0095] [6. Processing flow] The flow of processing in the power supply control device (power supply ECU 20) will be described with reference to Fig. 10. Fig. 10 is a flowchart showing an example of processing executed by the power supply control device according to the embodiment. In particular, Fig. 10 shows processing related to diagnosis of the backup power supply 22 by the microcomputer 21. In addition to processing related to diagnosis of the backup power supply 22, the power supply control ECU and the microcomputer 21 also perform processing related to power supply control for the vehicle.

[0096] 10, the microcomputer 21 remains in standby (step S102) until the IG is turned on (step S101, No). If the microcomputer 21 does not detect a trigger during standby (step S103, No), the microcomputer 21 returns to step S101 and continues to remain in standby until the IG is turned on.

[0097] When the IG is turned on (Yes in step S101), the microcomputer 21 ends the process related to the diagnosis. After that, the microcomputer 21 proceeds to the process related to the power supply control of the vehicle while it is running.

[0098] When the microcomputer 21 detects a trigger during standby (step S103, Yes), the process proceeds to step S104. For example, the trigger may be a user (key) approaching the vehicle, a door being unlocked, a certain time before the reserved use time, a certain time before the user's boarding time predicted from the history, etc.

[0099] That is, the microcomputer 21 detects the trigger before the IG is turned on, and starts diagnosing the backup power supply 22 by proceeding to step S104.

[0100] If the time elapsed since the previous diagnosis is equal to or greater than the threshold value α (step S104, Yes), the microcomputer 21 proceeds to step S105 and continues the diagnosis. On the other hand, if the time elapsed since the previous diagnosis is less than the threshold value α (step S104, No), the microcomputer 21 ends the process. The threshold value α is, for example, one week.

[0101] In this way, when the microcomputer 21 detects a trigger (step S103, Yes) and the time that has elapsed since the last diagnosis is equal to or greater than the threshold (step S104, Yes), the microcomputer 21 starts the diagnosis before the user gets into the vehicle (steps S105 and after). This makes it possible to reliably diagnose the deterioration of the backup power supply 22 while reducing the frequency of the diagnosis.

[0102] If the SOC of the backup power supply is greater than the threshold β (recharge threshold) (step S105, No), the microcomputer 21 performs a deterioration diagnosis due to discharging from the backup power supply 22 (step S106). On the other hand, if the SOC of the backup power supply is equal to or less than the threshold β (recharge threshold) (step S105, Yes), the microcomputer 21 performs a deterioration diagnosis due to charging to the backup power supply 22 (step S107).

[0103] As shown in the portion following t41 in FIG. 6, even when the microcomputer 21 performs deterioration diagnosis by charging, it may perform deterioration diagnosis by discharging and deterioration diagnosis by charging in combination.

[0104] The flow of the deterioration diagnosis due to discharge (step S106 in FIG. 10) will be described with reference to FIG 11. FIG 11 is a flowchart showing an example of the deterioration diagnosis due to discharge according to the embodiment.

[0105] As shown in FIG. 11, first, the microcomputer 21 estimates the EOL cell resistance value of the backup power supply 22 based on the SOC of the backup power supply, the temperature of the backup power supply 22, and the cell resistance value map (step S201).

[0106] Thereafter, the microcomputer 21 discharges the backup power supply 22 (step S202) and calculates (step S203) the cell resistance value of the backup power supply 22. Then, the microcomputer 21 determines whether the cell resistance value of the backup power supply 22 is less than the EOL cell resistance value (step S204).

[0107] When the microcomputer 21 determines that the cell resistance of the backup power supply 22 is equal to or greater than the EOL cell resistance (step S204, No), the microcomputer 21 determines that the cell resistance has deteriorated. In this case, the microcomputer 21 diagnoses that backup is not possible (step S207) and ends the process.

[0108] Furthermore, when the microcomputer 21 determines that the cell resistance value of the backup power supply 22 is less than the EOL cell resistance value (step S204, Yes), it determines that the cell resistance has not deteriorated. In this case, the microcomputer 21 determines whether the previous capacity deterioration rate of the backup power supply 22 exceeds the EOL deterioration rate (step S205).

[0109] When the microcomputer 21 determines that the previous capacity deterioration rate of the backup power source 22 is equal to or lower than the EOL deterioration rate (step S205, No), it determines that the capacity of the backup power source 22 has deteriorated. In this case, the microcomputer 21 diagnoses that backup is impossible (step S207) and ends the process.

[0110] Moreover, when the microcomputer 21 determines that the previous capacity deterioration rate of the backup power source 22 exceeds the EOL deterioration rate (step S205, Yes), it diagnoses that backup is possible (step S206) and ends the process.

[0111] The flow of deterioration diagnosis due to charging (step S107 in FIG. 10) will be described with reference to FIG 12. FIG 12 is a flowchart showing an example of deterioration diagnosis due to charging according to the embodiment.

[0112] As shown in FIG. 12, first, the microcomputer 21 charges the backup power supply 22 (step S301), and calculates the capacity deterioration rate of the backup power supply 22 (step S302).

[0113] Then, the microcomputer 21 determines whether the capacity deterioration rate exceeds the EOL capacity deterioration rate (step S303). When the microcomputer 21 determines that the capacity deterioration rate is equal to or lower than the EOL capacity deterioration rate (step S303, No), it determines that the capacity of the backup power source 22 has deteriorated. In this case, the microcomputer 21 diagnoses that backup is impossible (step S306) and ends the process.

[0114] Furthermore, when the microcomputer 21 determines that the capacity deterioration rate exceeds the EOL capacity deterioration rate (step S303, Yes), it determines that the capacity of the backup power source 22 has not deteriorated, and stores the capacity deterioration rate as the previous capacity deterioration rate (step S304). In this case, the microcomputer 21 diagnoses that backup is possible (step S305), and ends the process.

[0115] The microcomputer 21 may use a combination of the above-described triggers. For example, the microcomputer 21 detects a trigger when the time is a certain time before the reserved use time and the user approaches within a certain range from the vehicle.

[0116] [7. Notes] As an appendix, the features of the present invention are as follows: (1) A controller is provided for diagnosing a degree of deterioration of a backup power supply that supplies power to a load of a vehicle when a main power supply that supplies power to the load fails, The controller: When detecting an occurrence of an event indicating that a user is getting into the vehicle, the diagnosis is started before the user gets into the vehicle. Power control device. (2) The controller: When it is detected that the user approaches within a certain range from the vehicle, the diagnosis is started. A power supply control device as described in (1). (3) The controller: When the distance between the vehicle and a key for unlocking the door of the vehicle becomes less than a threshold value, the user is detected to be approaching within a certain range of the vehicle. A power supply control device according to claim 2. (4) The controller: Initiating the diagnosis when it is detected that the vehicle door is unlocked. A power supply control device according to any one of (1) to (3). (5) The controller: The time when the user reserved the use of the vehicle is acquired, and when it is detected that the time is a certain time before the reserved use time, the diagnosis is started. A power supply control device according to any one of (1) to (4). (6) The controller: The diagnosis is started when it is detected that the time has come a certain time before a predicted time at which the user will start driving the vehicle, which is predicted based on a history of the time at which the user will start driving the vehicle. A power supply control device according to any one of (1) to (5). (7) The controller: When the SOC of the backup power supply is equal to or lower than a threshold, the diagnosis is performed by charging the backup power supply. A power supply control device according to any one of (1) to (6). (8) The controller: The occurrence of an event indicating that the user will get into the vehicle is detected, and when the time that has elapsed since the last diagnosis is equal to or greater than a threshold, the diagnosis is started before the user gets into the vehicle. A power supply control device according to any one of (1) to (7). (9) a controller for diagnosing a degree of deterioration of a backup power supply that supplies power to a load of a vehicle when a main power supply that supplies power to the load fails; When detecting an occurrence of an event indicating that a user is getting into the vehicle, the diagnosis is started before the user gets into the vehicle. Power control method. (10) A controller that diagnoses a degree of deterioration of a backup power supply that supplies power to a load of a vehicle when a main power supply that supplies power to the load fails, When detecting an occurrence of an event indicating that a user is getting into the vehicle, the diagnosis is started before the user gets into the vehicle. A power control program that executes the process.

[0117] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0118] 10 Main power supply 11, 241 DC / DC 12 PbB 20 Power ECU 21 Microcomputer 22 Backup power supply 30 1st system load 31, 51 Steering motor 40 General load 50 2nd system load 60 Autonomous Driving Control ECU 70 Door lock control ECU 80 Steer-by-wire ECU 110 1st system 120 2nd system 221 LiB 231 First voltage sensor 232 Second voltage sensor 251 Battery Switch 252 Bypass Switch 253 Intersystem Switch

Claims

1. A controller is provided for diagnosing a degree of deterioration of a backup power supply that supplies power to a load of a vehicle when a main power supply that supplies power to the load fails, The controller: When detecting an occurrence of an event indicating that a user is getting into the vehicle, the diagnosis is started before the user gets into the vehicle. Power control device.

2. The controller: When it is detected that the user approaches within a certain range from the vehicle, the diagnosis is started. The power supply control device according to claim 1 .

3. The controller: When the distance between the vehicle and a key for unlocking the door of the vehicle becomes less than a threshold value, the user is detected to be approaching within a certain range of the vehicle. The power supply control device according to claim 2.

4. The controller: Initiating the diagnosis when it is detected that the vehicle door is unlocked. The power supply control device according to claim 1 .

5. The controller: The time when the user reserved the use of the vehicle is acquired, and when it is detected that the time is a certain time before the reserved use time, the diagnosis is started. The power supply control device according to claim 1 .

6. The controller: The diagnosis is started when it is detected that the time has come a certain time before a predicted time at which the user will start driving the vehicle, which is predicted based on a history of the time at which the user will start driving the vehicle. The power supply control device according to claim 1 .

7. The controller: When the SOC of the backup power supply is equal to or lower than a threshold, the diagnosis is performed by charging the backup power supply. The power supply control device according to claim 1 .

8. The controller: The occurrence of an event indicating that the user will get into the vehicle is detected, and when the time that has elapsed since the last diagnosis is equal to or greater than a threshold, the diagnosis is started before the user gets into the vehicle. The power supply control device according to claim 1 .

9. a controller for diagnosing a degree of deterioration of a backup power supply that supplies power to a load of a vehicle when a main power supply that supplies power to the load fails; When detecting an occurrence of an event indicating that a user is getting into the vehicle, the diagnosis is started before the user gets into the vehicle. Power control method.

10. A controller for diagnosing a degree of deterioration of a backup power supply that supplies power to a load of a vehicle when a main power supply that supplies power to the load fails, When detecting an occurrence of an event indicating that a user is getting into the vehicle, the diagnosis is started before the user gets into the vehicle. A power control program that executes the process.

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