Power supply control device and power supply control method

Abstract

To provide a power source control device capable of accurately diagnosing whether or not a main power source can be backed up by an auxiliary power source, and a power source control method.SOLUTION: A power source control device comprises a first determination unit, a second determination unit, and a diagnosis unit. The first determination unit calculates an internal resistance value of an auxiliary power source by discharging the auxiliary power source in predetermined timing and determines deterioration of internal resistance of the auxiliary power source based on the internal resistance value. The second determination unit calculates a capacity deterioration rate of the auxiliary power source by discharging the auxiliary power source when a value indicating a charge state of the auxiliary power source is below a re-charge threshold, and determines the deterioration of the capacity of the auxiliary power source based on the capacity deterioration rate. The diagnosis unit diagnoses whether or not a main power source can be backed up by the auxiliary power source based on a determination result of at least any one of the first determination unit and the second determination unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, there has been a redundant power supply system that is equipped with a main power supply and an auxiliary power supply so that, even if a power failure occurs while a vehicle is traveling in autonomous driving mode, the vehicle can be evacuated to a safe location and stopped, and in the event of a failure in the main power supply power system, the auxiliary power supply power system supplies power to on-board equipment (load) for autonomous driving (see, for example, Patent Document 1).

[0003] Vehicles equipped with a redundant power supply system are diagnosed to determine whether the auxiliary power supply can back up the main power supply, and if it is determined that backup is possible, the vehicle is allowed to transition to autonomous driving. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-182864 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when diagnosing whether or not the auxiliary power supply is capable of backing up the main power supply, if the auxiliary power supply is deteriorated, there is a risk that the auxiliary power supply may be erroneously diagnosed as capable of backing up when in fact it is not capable of providing backup.

[0006] One aspect of the embodiment has been made in consideration of the above, and aims to provide a power supply control device and a power supply control method that can accurately diagnose whether it is possible to back up the main power supply using an auxiliary power supply. [Means for solving the problem]

[0007] A power supply control device according to an aspect of the embodiment includes a first determination unit, a second determination unit, and a diagnosis unit. The first determination unit discharges an auxiliary power supply at a predetermined timing to calculate an internal resistance value of the auxiliary power supply, and determines deterioration of the internal resistance of the auxiliary power supply based on the internal resistance value. The second determination unit charges the auxiliary power supply when a value indicating the charge state of the auxiliary power supply falls below a recharge threshold to calculate a capacity deterioration rate of the auxiliary power supply, and determines deterioration of the capacity of the auxiliary power supply based on the capacity deterioration rate. The diagnosis unit diagnoses whether or not the auxiliary power supply can back up a main power supply based on a determination result of at least one of the first determination unit and the second determination unit. Effect of the Invention

[0008] A power supply control device and a power supply control method according to an aspect of the embodiment provide an effect of being able to accurately diagnose whether or not the auxiliary power supply is capable of backing up the main power supply. [Brief description of the drawings]

[0009] [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 showing an example of processing executed by a diagnosing unit of a power supply control device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a power supply control device and a power supply control method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment. In the following, 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.

[0011] 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.

[0012] The power supply control device according to the embodiment may be installed in any device that has a main power supply and an auxiliary power supply and that backs up the main power supply with the auxiliary power supply in the event of a power failure in the main power supply.

[0013] [1. Power supply control device configuration] Fig. 1 is an explanatory diagram showing a configuration example of a power supply control device according to an embodiment. As shown in Fig. 1, the power supply control device 1 according to the embodiment is connected to a main power supply 10, a first load 101, a general load 102, a second load 103, and an automatic operation control device 100. The power supply control device 1 includes a first system 110 that supplies power from the main power supply 10 to the first load 101 and the general load 102, and a second system 120 that supplies power from an auxiliary power supply 20 (described later) to the second load 103.

[0014] The first load 101 includes a load for autonomous driving. For example, the first load 101 includes a steering motor, an electric brake device, an in-vehicle camera, a radar, etc. that operate during autonomous driving. The general load 102 includes, for example, a display, an air conditioner, an audio device, a video device, various lights, etc.

[0015] The second load 103 has the same function as the first load 101. The second load 103 includes devices that operate during automatic driving, such as a steering motor, an electric brake device, an in-vehicle camera, and a radar. The first load 101, the general load 102, and the second load 103 operate with power supplied from the power supply control device 1. The automatic driving control device 100 is a device that operates the first load 101 or the second load 103 to control the automatic driving of a vehicle.

[0016] The main power source 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 source 10 may be any secondary battery other than the PbB 12.

[0017] 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.

[0018] When the main power supply 10 is installed in an engine vehicle, an alternator (generator) is provided instead of the DC / DC 11. The DC / DC 11 charges the PbB 12, supplies power to the first load 101 and the general load 102, supplies power to the second load 103, and charges the auxiliary power supply 20 described below.

[0019] The power supply control device 1 includes an auxiliary power supply 20, an inter-system switch 41, a battery switch 42, a bypass switch 43, a control unit 3, a first voltage sensor 51, a second voltage sensor 52, a DC / DC 53, and a storage unit 6. The auxiliary power supply 20 is a backup power supply in the event that power supply from the main power supply 10 becomes impossible. The auxiliary power supply 20 includes a lithium ion battery (hereinafter referred to as "LiB21"). Note that the battery of the auxiliary power supply 20 may be any secondary battery other than the LiB21.

[0020] The inter-system switch 41 is provided on the inter-system line 130 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 42 is a switch capable of connecting and disconnecting the LiB 21 to the second system 120. Specifically, the battery switch 42 is a switch capable of connecting and disconnecting the LiB 21 to the bypass switch 43 and the DC / DC 53.

[0021] The bypass switch 43 is a switch that can connect and disconnect the battery switch 42 and the second system 120. The DC / DC 53 is connected in parallel to the bypass switch 43, and adjusts the voltage output from the LiB 21 and the voltage input to the LiB 21.

[0022] The first voltage sensor 51 is provided in the first system 110, detects the voltage of the first system 110, and outputs the detection result to the control unit 3. The second voltage sensor 52 is provided in the second system 120, detects the voltage of the second system 120, and outputs the detection result to the control unit 3.

[0023] The control unit 3 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), etc., and various circuits. The control unit 3 may be configured with hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0024] The control unit 3 controls the operation of the power supply control device 1 by causing the CPU to execute a program stored in the ROM using the RAM as a work area. The control unit 3 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 51 and the second voltage sensor 52. A specific example of a method for detecting a ground fault by the control unit 3 will be described later.

[0025] When the control unit 3 detects a ground fault in the first system 110 or the second system 120, it notifies the automatic driving control device 100 of that fact. When the control unit 3 detects a ground fault in the first system 110 or the second system 120, it may notify the automatic driving control device 100 of a state in which automatic driving is impossible. When the control unit 3 does not detect a ground fault in the first system 110 or the second system 120, it may notify the automatic driving control device 100 of a state in which automatic driving is possible.

[0026] When a power failure such as a ground fault occurs in the first system 110, the control unit 3 cuts off the system-to-system switch 41, and turns on the battery switch 42 and the bypass switch 43 to supply power from the auxiliary power supply 20 to the second load 103. When a power failure such as a ground fault occurs in the second system 120, the control unit 3 cuts off the system-to-system switch 41, and supplies power from the main power supply 10 to the first load 101 and the general load 102 with the battery switch 42 cut off.

[0027] As a result, even if a ground fault occurs in one of the systems during autonomous driving, the power supply control device 1 can use the other system and have the autonomous driving control device 100 evacuate the vehicle to a safe place and stop it.

[0028] Moreover, control unit 3 includes first determination unit 31, second determination unit 32, and diagnosis unit 33. First determination unit 31 discharges auxiliary power supply 20 at a predetermined timing, for example, at start-up, to calculate an internal resistance (hereinafter, referred to as "cell resistance") value of auxiliary power supply 20, and determines deterioration of the cell resistance of auxiliary power supply 20 based on the cell resistance value.

[0029] By setting the predetermined timing as the time of start-up, it is possible to determine the deterioration of the cell resistance from the state of auxiliary power supply 20 immediately before the vehicle starts to run. In the following explanation, the predetermined timing is set to the time of start-up, but the predetermined timing is not limited to the time of start-up, and may be any timing that does not affect the running of the vehicle, such as while the vehicle is stopped after start-up or when the ignition is off.

[0030] The second determination unit 32 charges the auxiliary power supply 20 when the SOC (State Of Charge), a value indicating the charging state of the auxiliary power supply 20, falls below a recharge threshold, calculates the capacity degradation rate of the auxiliary power supply 20, and determines the degradation of the capacity of the auxiliary power supply 20 based on the capacity degradation rate.

[0031] Diagnosis unit 33 diagnoses whether or not the auxiliary power supply 20 can back up the main power supply 10, based on the determination result of at least one of first determination unit 31 and second determination unit 32. In this way, the power supply control device 1 can accurately diagnose whether or not the auxiliary power supply 20 can back up the main power supply 10, by taking into account the deterioration of the cell resistance of the auxiliary power supply 20 and the deterioration of the capacity of the auxiliary power supply 20. An example of the operation of control unit 3 will be described later with reference to Figures 2 to 5 and 8 to 9.

[0032] The storage unit 6 is, for example, an information storage device such as a data flash, and stores a cell resistance value map 61 and a previous capacity deterioration rate 62. An example of the cell resistance value map 61 will be described later with reference to Fig. 8. Next, the operation of the power supply control device 1 will be described with reference to Figs. 2 to 9.

[0033] [2. Normal operation of the power supply control device] Under normal circumstances when no ground faults have occurred in the first system 110 and the second system 120, the control unit 3 turns off the battery switch 42, turns on the system switch 41 while keeping the bypass switch 43 conductive, and supplies power from the main power source 10 to the first load 101, the general load 102, and the second load 103, as shown in FIG. 2.

[0034] [3. Operation of power supply control device when a ground fault occurs] Next, the operation of the power supply control device 1 when a ground fault occurs will be described with reference to Figures 3 to 5. As shown in Figure 3, in the power supply control device 1, for example, when a ground fault 200 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 51 becomes equal to or lower than the ground fault threshold value.

[0035] Furthermore, in the power supply control device 1, when a ground fault 201 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 52 becomes equal to or lower than the ground fault threshold value.

[0036] Therefore, when the voltage detected by at least one of the first voltage sensor 51 and the second voltage sensor 52 becomes equal to or lower than the ground fault threshold, the control unit 3 detects an abnormality in the power supply, turns off the inter-system switch 41, and turns on the battery switch 42. At this time, the control unit 3 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120.

[0037] Thereafter, if the voltage detected by the first voltage sensor 51 is below the ground fault threshold for a predetermined time or more and the voltage detected by the second voltage sensor 52 returns to exceed the ground fault threshold within the predetermined time, the control unit 3 determines that a ground fault 200 has occurred in the first system 110.

[0038] 4, the control unit 3 supplies power from the auxiliary power supply 20 to the second load 103 and notifies the automatic driving control device 100 of this fact. As a result, the automatic driving control device 100 operates the second load 103 with the power supplied from the auxiliary power supply 20, and can evacuate the vehicle to a safe place and stop the vehicle.

[0039] In addition, after the control unit 3 has provisionally determined 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 52 is below the ground fault threshold and the voltage detected by the first voltage sensor 51 returns to exceed the ground fault threshold within a predetermined time, the control unit 3 finally determines that a ground fault 201 has occurred in the second system 120.

[0040] 5, the control unit 3 turns off the battery switch 42, supplies power from the main power supply 10 to the first load 101, and notifies the automatic driving control device 100 of this fact. As a result, the automatic driving control device 100 can operate the first load 101 with the power supplied from the main power supply 10, and can evacuate the vehicle to a safe place and stop the vehicle.

[0041] Furthermore, in the power supply control device 1, when the first load 101 or the general load 102 temporarily falls into an overload state, rather than the ground faults 200 and 201, the voltage detected by the first voltage sensor 51 may temporarily fall below the ground fault threshold. Furthermore, in the power supply control device 1, when the second load 103 temporarily falls into an overload state, the voltage detected by the second voltage sensor 52 may temporarily fall below the ground fault threshold.

[0042] In this case, in the power supply control device 1, power is continuously supplied from the main power supply 10 to the first load 101 and the general load 102, and power is supplied from the auxiliary power supply 20 to the second load 103. Therefore, after the control unit 3 provisionally determines that a ground fault has occurred in the first system 110 or the second system 120, if the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 both return to exceeding the ground fault threshold before a predetermined time has elapsed, the control unit 3 officially determines that there is no abnormality in the power supply. Thereafter, in order to return to the normal operation shown in FIG. 2, the control unit 3 turns off the battery switch 42 and re-opens the inter-system switch 41.

[0043] [4. Auxiliary power supply diagnostic operation] 6 to 9, a description will now be given of a diagnostic operation in which the control unit 3 of the power supply control device 1 diagnoses whether or not the auxiliary power supply 20 can back up the main power supply 10. Here, the auxiliary power supply 20 can back up the main power supply 10 if the SOC exceeds a predetermined lower limit value for which backup is possible.

[0044] However, if the auxiliary power supply 20 is deteriorated, it may not be able to back up the main power supply 10 even if the SOC exceeds the lower limit value at which backup is possible. Therefore, in order to accurately diagnose whether backup is possible or not, it is necessary to take the deterioration of the auxiliary power supply 20 into consideration.

[0045] One method for determining the deterioration of the auxiliary power supply 20 is a determination method based on the capacity deterioration rate. The capacity deterioration rate can be calculated, for example, by recharging the auxiliary power supply 20 with a low charge level and based on the rate of increase in the charge level of the auxiliary power supply 20 at that time. The capacity deterioration rate can also be calculated by charging the auxiliary power supply 20 with a low charge level until it is fully charged and based on the SOC of the auxiliary power supply 20 at that time.

[0046] Therefore, for example, when the auxiliary power supply 20 naturally discharges and the SOC falls below the recharge threshold, it is possible to recharge the auxiliary power supply 20 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.

[0047] However, it may take several months for the SOC of auxiliary power supply 20 to become less than the recharge threshold due to natural discharge. For this reason, for example, if a backup availability diagnosis is performed based on the SOC every time the device is started up, the diagnosis will be based on a capacity deterioration rate from up to several months ago, and there is a risk that an accurate diagnosis of the backup availability cannot be performed.

[0048] Therefore, as shown in FIG. 6, the diagnostic unit 33 of the power supply control device 1 according to the embodiment discharges the auxiliary power supply 20 and calculates the cell resistance at a predetermined timing during startup, for example, every time the vehicle's IG (ignition switch) is turned on during startup.

[0049] Then, the diagnostic unit 33 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 auxiliary power supply 20 exceeds the recharge threshold, it diagnoses that backup is possible.

[0050] In this embodiment, the capacity degradation rate when auxiliary power supply 20 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, diagnosing unit 33 can accurately diagnose whether or not backup is possible by taking into account the degradation of the cell resistance that is determined every time the battery is started up.

[0051] Thereafter, when the SOC of auxiliary power supply 20 falls below the recharge threshold, diagnostic unit 33 charges auxiliary power supply 20 and calculates the current capacity deterioration rate. Then, diagnostic unit 33 determines the deterioration of cell resistance, 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 auxiliary power supply 20 exceeds the recharge threshold, diagnostic unit 33 diagnoses that backup is possible. In this way, diagnostic unit 33 can accurately diagnose whether backup is possible or not by taking into account the deterioration of cell resistance determined every time the device is started and the latest capacity deterioration rate.

[0052] Specifically, when the IG of the vehicle is turned on, first determination unit 31 of control unit 3 estimates the SOC of auxiliary power supply 20 and acquires the temperature from auxiliary power supply 20. Then, first determination unit 31 estimates an EOL (End Of Life) resistance value of auxiliary power supply 20 based on the SOC of auxiliary power supply 20, the temperature of auxiliary power supply 20, and a cell resistance value map 61.

[0053] The EOL resistance value is a value exceeding the upper limit of the cell resistance value at which the auxiliary power supply 20 can perform backup, and is the cell resistance value of the auxiliary power supply 20 that has reached the end of its product life. In other words, if the cell resistance value of the auxiliary power supply 20 is less than the EOL resistance value, then the auxiliary power supply 20 is in a state where backup is possible with respect to the cell resistance.

[0054] Here, an example of the cell resistance value map 61 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 61 is a map showing the relationship between the SOC and temperature of the auxiliary power supply 20 and the EOL resistance value in that state. The first determination unit 31 obtains from the cell resistance value map 61 the EOL cell resistance value corresponding to the estimated SOC of the auxiliary power supply 20 and the obtained temperature.

[0055] Next, as shown in FIG. 8 , with the system switch 41 cut off, the first judgment unit 31 cuts off the bypass switch 43, turns on the battery switch 42, controls the DC / DC 53, and supplies a diagnostic current from the auxiliary power supply 20 to the second load 103 via the DC / DC 53.

[0056] At this time, the first determination unit 31 adjusts the DC / DC converter 53 so that a current smaller than that during actual backup is passed. This allows the first determination unit 31 to minimize the amount of discharge of the auxiliary power supply 20.

[0057] Then, the first determination unit 31 calculates the cell resistance R=ΔV / ΔI from the current ΔI and voltage ΔV discharged from the auxiliary power supply 20 at this time. At this time, the first determination unit 31 can obtain the current ΔI from a current sensor (not shown) provided in the second system 120 or the auxiliary power supply 20, and obtain the voltage ΔV from the second voltage sensor 52.

[0058] If the calculated cell resistance value is less than the EOL cell resistance value at that time, the first judgment unit 31 judges 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 judges that the cell resistance has deteriorated.

[0059] At this time, if the previous capacity deterioration rate exceeds the EOL deterioration rate (for example, 80%), the second determination unit 32 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.

[0060] Then, if the first determination unit 31 determines that the cell resistance has not deteriorated, the second determination unit 32 determines that the capacity has not deteriorated, and the SOC exceeds the recharge threshold, the diagnosis unit 33 diagnoses that the auxiliary power supply 20 can back up the main power supply 10. Note that in this diagnosis, the deterioration of the capacity may be omitted as a determination factor.

[0061] Thereafter, when the SOC of the auxiliary power supply 20 falls below the recharge threshold, the second determination unit 32 turns on the inter-system switch 41 and supplies power from the main power supply 10 to the auxiliary power supply 20 via the DC / DC converter 53 to charge the auxiliary power supply 20, as shown in FIG. 9 . Then, the second determination unit 32 calculates the capacity deterioration rate of the auxiliary power supply 20.

[0062] At this time, second determination unit 32 calculates the capacity deterioration rate based on, for example, the rate of increase in the charge amount in auxiliary power supply 20 when charging is performed. Note that second determination unit 32 may calculate the capacity deterioration rate based on the SOC of auxiliary power supply 20 when charging for a predetermined charging time required for auxiliary power supply 20 to be fully charged is completed.

[0063] Here, the recharge threshold is set to a value larger than the lower limit of the SOC at which the auxiliary power supply 20 can back up the main power supply 10. For example, as shown in Fig. 6, the recharge threshold is set to a value obtained by adding the sensor error / calculation error and the maximum discharge amount in 30 days to the lower limit of the SOC at which backup is possible.

[0064] This allows the power supply control device 1 to guarantee a backup-enabled SOC the next time the IG is turned on, if the period from when the IG was last turned off to when it is next turned on is within 30 days.

[0065] The second determination unit 32 determines that the capacity has not deteriorated if the calculated capacity deterioration rate exceeds the EOL deterioration rate (e.g., 80%), and determines that the capacity has deteriorated if the calculated capacity deterioration rate is equal to or less than the EOL deterioration rate.

[0066] Again, first determination unit 31 determines whether or not the cell resistance has deteriorated based on the cell resistance value. Then, when first determination unit 31 determines that the cell resistance has not deteriorated and second determination unit 32 determines that the capacity has not deteriorated, diagnosis unit 33 diagnoses that auxiliary power supply 20 can back up main power supply 10.

[0067] In this diagnosis, the deterioration of the cell resistance may be omitted from the criteria for judgment. In this way, the power supply control device 1 can accurately diagnose whether or not backup is possible by taking into account the deterioration of the cell resistance and the capacity deterioration rate, which are judged every time the power supply control device 1 is started up.

[0068] In addition, since the power supply control device 1 discharges the auxiliary power supply 20, albeit a small amount, each time the IG is turned on, the SOC of the auxiliary power supply 20 falls to the recharge threshold value earlier than it falls below the recharge threshold value due to natural discharge.

[0069] As a result, the power supply control device 1 increases the frequency with which it calculates the period during which the auxiliary power supply 20 is recharged, i.e., the capacity deterioration rate of the auxiliary power supply 20, thereby improving the reliability of the capacity deterioration determination result based on the capacity deterioration rate. [5. Processing performed by the control unit] Next, a process executed by the control unit 3 of the power supply control device 1 according to the embodiment will be described with reference to Fig. 10. Fig. 10 is a flowchart showing an example of a process executed by the diagnosis unit of the power supply control device according to the embodiment.

[0070] For example, when the IG of a vehicle equipped with the power supply control device 1 is turned on, the control unit 3 starts the process shown in Fig. 10. Specifically, as shown in Fig. 10, the first determination unit 31 first estimates the EOL cell resistance value of the auxiliary power supply 20 based on the SOC of the auxiliary power supply, the temperature of the auxiliary power supply 20, and the cell resistance value map 61 (step S101).

[0071] Thereafter, the first determination unit 31 discharges the auxiliary power supply 20 (step S102) and calculates the cell resistance value of the auxiliary power supply 20 (step S103). Then, the first determination unit 31 determines whether the cell resistance value of the auxiliary power supply 20 is less than the EOL cell resistance value (step S104).

[0072] When the first determination unit 31 determines that the cell resistance of the auxiliary power supply 20 is equal to or greater than the EOL cell resistance (step S104, No), it determines that the cell resistance has deteriorated. In this case, the diagnosis unit 33 diagnoses that backup is impossible (step S112) and ends the process.

[0073] Furthermore, when the first determination unit 31 determines that the cell resistance value of the auxiliary power supply 20 is less than the EOL cell resistance value (Yes in step S104), it determines that the cell resistance has not deteriorated. In this case, the second determination unit 32 determines whether the previous capacity deterioration rate 62 of the auxiliary power supply 20 exceeds the EOL deterioration rate (step S105).

[0074] When the second determination unit 32 determines that the previous capacity deterioration rate 62 of the auxiliary power supply 20 is equal to or lower than the EOL deterioration rate (step S105, No), it determines that the capacity of the auxiliary power supply 20 has deteriorated. In this case, the diagnosis unit 33 diagnoses that backup is impossible (step S112) and ends the process.

[0075] Furthermore, if second determination unit 32 determines that previous capacity deterioration rate 62 of auxiliary power supply 20 exceeds the EOL deterioration rate (step S105, Yes), second determination unit 32 determines whether the SOC of auxiliary power supply 20 is equal to or lower than the recharge threshold (step S106).

[0076] If second determination unit 32 determines that the SOC of auxiliary power supply 20 exceeds the recharge threshold (step S106, No), diagnosis unit 33 diagnoses that backup is possible (step S111) and ends the process.

[0077] If second determination unit 32 determines that the SOC of auxiliary power supply 20 is equal to or lower than the recharge threshold (Yes in step S106), it charges auxiliary power supply 20 (step S107) and calculates the capacity deterioration rate of auxiliary power supply 20 (step S108).

[0078] Then, the second determination unit 32 determines whether the capacity deterioration rate exceeds the EOL capacity deterioration rate (step S109). If the second determination unit 32 determines that the capacity deterioration rate is equal to or less than the EOL capacity deterioration rate (step S109, No), it determines that the capacity of the auxiliary power supply 20 has deteriorated. In this case, the diagnosis unit 33 diagnoses that backup is impossible (step S112) and ends the process.

[0079] Furthermore, when second determination unit 32 determines that the capacity deterioration rate exceeds the EOL capacity deterioration rate (step S109, Yes), it determines that the capacity of auxiliary power supply 20 has not deteriorated, and stores the capacity deterioration rate as previous capacity deterioration rate 62 in storage unit 6 (step S110). In this case, diagnosis unit 33 diagnoses that backup is possible (step S111), and ends the process.

[0080] 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]

[0081] 1 Power supply control device 10 Main power 11 DC / DC 12 PbB 20 Auxiliary power supply 21 LiB 3. Control Unit 31 1st Judgment Section 32 Second Judgment Section 33 Diagnostic Department 41 Intersystem switch 42 Battery switch 43 Bypass Switch 51 First voltage sensor 52 Second voltage sensor 53 DC / DC 6 Memory section 61 Cell resistance map 62 Previous capacity deterioration rate 100 Automatic driving control device 101 1st load 102 General load 103 2nd load 110 1st system 120 2nd system

Claims

1. a first determination unit that calculates an internal resistance value of the auxiliary power supply by discharging the auxiliary power supply at a predetermined timing, and determines deterioration of the internal resistance of the auxiliary power supply based on the internal resistance value; a second determination unit that charges the auxiliary power supply when a value indicating the charge state of the auxiliary power supply falls below a recharge threshold, calculates a capacity deterioration rate of the auxiliary power supply, and determines deterioration of the capacity of the auxiliary power supply based on the capacity deterioration rate; a diagnosis unit that diagnoses whether or not the auxiliary power supply can back up the main power supply based on a determination result of at least one of the first determination unit and the second determination unit; A power supply control device comprising:

2. The recharge threshold is The value is set to a value greater than the lower limit of the value indicating the charge state where the backup is possible.

2. The power supply control device according to claim 1 .

3. a first determination unit of the power supply control device, discharging the auxiliary power supply at a predetermined timing to calculate an internal resistance value of the auxiliary power supply, and performing a first determination of deterioration of the internal resistance of the auxiliary power supply based on the internal resistance value; The second determination unit of the power supply control device charging the auxiliary power supply when a value indicating the charge state of the auxiliary power supply falls below a recharge threshold, calculating a capacity deterioration rate of the auxiliary power supply, and performing a second determination of deterioration of the capacity of the auxiliary power supply based on the capacity deterioration rate; A diagnostic unit of the power supply control device, Based on at least one of the first and second determinations, a diagnosis is made as to whether or not the auxiliary power supply can back up the main power supply. A power supply control method comprising:

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