Battery diagnostic device, method and program

Abstract

To provide a battery diagnostic device that can improve diagnostic accuracy of a battery by enhancing probability in which diagnostic discharge processing is successful.SOLUTION: A battery diagnostic device that diagnoses a state of a battery mounted on a vehicle, comprises: a discharge processing unit that performs diagnostic discharge from the battery toward a predetermined on-vehicle apparatus at second timing in which predetermined time has passed from first timing; an acquisition unit that acquires a physical amount indicating a state of the battery during diagnostic discharge; a determination unit that determines whether deterioration diagnosis of the battery is possible or not on the basis of the physical amount; a recording unit that records the predetermined time as discharge successful time when it is determined that the deterioration diagnosis is possible; and a diagnostic unit that performs deterioration diagnosis of the battery on the basis of the physical amount when it is determined that the deterioration diagnosis is possible.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a battery diagnostic device that diagnoses the condition of a battery mounted in a vehicle. [Background technology]

[0002] Patent Document 1 discloses a battery diagnostic method for diagnosing deterioration of a sub-battery that can back up the main battery during autonomous driving. In this battery diagnostic device, if deterioration of the sub-battery cannot be diagnosed by the initial diagnostic discharge process, the diagnostic discharge process is repeatedly performed multiple times to increase the chances of diagnosing deterioration of the sub-battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-064649 A Summary of the Invention [Problem to be solved by the invention]

[0004] Even if multiple opportunities to perform battery deterioration diagnosis are provided, as in the battery diagnosis method described in Patent Document 1, if the timing of diagnostic discharge often overlaps with the timing of current demand by on-board devices, it may be necessary to charge and discharge the battery multiple times before the diagnostic discharge process is successful, or all diagnostic discharge processes may fail. If all diagnostic discharge processes fail and battery deterioration diagnosis cannot be performed, the accuracy of diagnosis decreases.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a battery diagnostic device and the like that can increase the probability of successful diagnostic discharge processing and improve the accuracy of battery diagnosis. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the disclosed technology is a battery diagnostic device that diagnoses the condition of a battery mounted on a vehicle, the battery diagnostic device comprising: a discharge processing unit that performs diagnostic discharge from the battery toward a specified vehicle-mounted device at a second timing that is a specified time after a first timing; an acquisition unit that acquires physical quantities that indicate the condition of the battery during the diagnostic discharge; a determination unit that determines whether or not battery degradation diagnosis is possible based on the physical quantities; a recording unit that records a specified time as a successful discharge time if it is determined that battery degradation diagnosis is possible; and a diagnosis unit that performs battery degradation diagnosis based on the physical quantities if it is determined that battery degradation diagnosis is possible. Effect of the Invention

[0007] According to the battery diagnostic device disclosed herein, the timing for performing the diagnostic discharge process is determined based on the time of past successful discharges, thereby making it possible to ensure a high probability of success in the diagnostic discharge process, thereby improving the accuracy of battery diagnosis. [Brief description of the drawings]

[0008] [Figure 1] A functional block diagram of a battery diagnosis device and its peripheral parts according to an embodiment. [Diagram 2] FIG. 1 shows a current path discharged from the second battery during diagnostic discharge processing. [Diagram 3] FIG. 13 is a diagram showing an example of changes in physical quantities of the second battery during diagnostic discharge processing; [Figure 4] FIG. 13 is a diagram showing an example of a successful discharge time recorded by a recording unit. [Diagram 5] FIG. 13 is a diagram showing an example of a discharge failure time recorded by a recording unit. [Figure 6A] 1 is a flowchart of a battery diagnostic process executed by a battery diagnostic device. [Figure 6B] 1 is a flowchart of a battery diagnostic process executed by a battery diagnostic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present disclosure relates to a battery diagnostic device that performs deterioration diagnosis of a sub-battery that can back up a main battery during autonomous driving. This battery diagnostic device records the timing when diagnostic discharge processing was successful (or failed) in the past, and performs future diagnostic discharge processing based on the recorded timing. This allows the battery diagnostic processing to be performed at a timing when the diagnostic discharge processing is highly likely to be successful, thereby improving the accuracy of battery diagnosis. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [composition] 1 is a functional block diagram of a battery diagnostic device 100 and its peripheral units according to an embodiment of the present disclosure. The functional block illustrated in FIG. 1 includes a first battery 11, a second battery 12, a first in-vehicle device 21, a second in-vehicle device 22, a connection switching unit 30, a generator 40, a control unit 60, and the battery diagnostic device 100.

[0011] The first battery 11, the first in-vehicle device 21, the connection switching unit 30, and the generator 40 are connected to one another by a first power line 51. The second battery 12 and the connection switching unit 30 are connected to one another by a second power line 52. The second in-vehicle device 22 and the connection switching unit 30 are connected to one another by a third power line 53. The second battery 12, the connection switching unit 30, the control unit 60, and the battery diagnostic device 100 are also connected to one another by signal lines (dotted lines in FIG. 1), and control signals, measured values, and the like are transmitted and received between them.

[0012] The battery diagnosis device 100 according to this embodiment is described taking as an example a case in which it is mounted on a vehicle equipped with a power supply system that is switchable between manual driving and automatic driving and requires a redundant power supply configuration.

[0013] The generator 40 is a device capable of outputting a predetermined electric power, such as an alternator, a DC-DC converter, etc. The electric power output by the generator 40 is supplied to the first battery 11, the first in-vehicle device 21, etc.

[0014] The first battery 11 is a secondary battery configured to be chargeable and dischargeable, such as a lead-acid battery or a lithium-ion battery. The first battery 11 stores the power output by the generator 40 and releases the power stored in the first in-vehicle device 21 and the connection switching unit 30. The first battery 11 is provided as a main battery used exclusively for driving the vehicle.

[0015] The second battery 12 is a secondary battery configured to be chargeable and dischargeable, such as a lead-acid battery or a lithium-ion battery. The second battery 12 stores the power output by the generator 40 and the power of the first battery 11 via the connection switching unit 30, and releases (supplies) the power stored in itself to the second in-vehicle device 22, etc. via the connection switching unit 30. This second battery 12 is provided redundantly so that even if the first battery 11 fails during automatic driving, a backup process can be performed to maintain the power supply to the second in-vehicle device 22 responsible for automatic driving in place of the first battery 11.

[0016] The first in-vehicle device 21 is a load that is mounted on the vehicle and consumes electric power. The first in-vehicle device 21 is configured to operate on electric power output by the generator 40 and / or electric power stored in the first battery 11.

[0017] The second vehicle device 22 is a load that consumes electric power mounted on the vehicle, and can be a device that requires a more stable power supply than the first vehicle device 21 during automatic driving of the vehicle. More specifically, the second vehicle device 22 is an important device related to the safe driving of the vehicle that requires a power supply of a predetermined period and a predetermined current from the second battery 12 even if the power supply from the first battery 11 fails, and can be a device that has an important function for safely evacuating the vehicle in an emergency during automatic driving, for example. The second vehicle device 22 is configured to operate with the electric power output by the generator 40 and / or the electric power stored in the first battery 11 during manual driving, and to operate with the electric power output by the generator 40 voltage-controlled by the DCDC converter 33 and / or the electric power stored in the first battery 11 and the electric power stored in the second battery 12 during automatic driving.

[0018] The connection switching unit 30 includes a first switch 31, a second switch 32, and a DCDC converter 33. The first switch 31 is disposed between the first power line 51 and the third power line 53 so as to be capable of opening and closing. The second switch 32 is disposed between the second power line 52 and the third power line 53 so as to be capable of opening and closing. For example, a semiconductor relay or a mechanical relay can be used for the first switch 31 and the second switch 32. The DCDC converter 33 is disposed between the first power line 51 and the second power line 52, and is a voltage converter that converts the voltage of the input power to a predetermined voltage and outputs it. For example, the DCDC converter 33 can be a step-up / step-down type DCDC converter that has both a step-down function of stepping down the voltage on the primary side and outputting it to the secondary side, and a step-up function of stepping up the voltage on the secondary side and outputting it to the primary side.

[0019] The control unit 60 is configured by an autonomous driving ECU (Electronic Control Unit) including, for example, a microcomputer, and controls the open / closed state of the first switch 31 and the second switch 32 of the connection switching unit 30 and the voltage instruction value of the DCDC converter 33 based on vehicle information (ignition ON / OFF state, manual driving / autonomous driving state, etc.) obtained from in-vehicle equipment not shown.

[0020] Specifically, when the vehicle is in a manual driving state, the control unit 60 closes the first switch 31 to connect the first power line 51 and the third power line 53, and opens the second switch 32 to separate the second power line 52 and the third power line 53. As a result, the second in-vehicle device 22 is directly supplied with the power output by the generator 40 and / or the power stored in the first battery 11. On the other hand, when the vehicle is in an automatic driving state, the control unit 60 opens the first switch 31 to separate the first power line 51 and the third power line 53, and closes the second switch 32 to connect the second power line 52 and the third power line 53. As a result, the second in-vehicle device 22 is indirectly supplied with the power output by the generator 40 and / or the power stored in the first battery 11 via the DCDC converter 33.

[0021] The battery diagnostic device 100 is a device for diagnosing the state of the second battery 12, and more specifically, is capable of diagnosing deterioration of the second battery 12. The battery diagnostic device 100 includes a discharge processing unit 101, an acquisition unit 102, a determination unit 103, a recording unit 104, and a diagnosis unit 105.

[0022] When the time comes to perform a deterioration diagnosis of the second battery 12, the discharge processing unit 101 performs a diagnostic discharge process to discharge for a first time from the second battery 12 to the first in-vehicle device 21 and the second in-vehicle device 22. The timing to perform this deterioration diagnosis is determined based on the discharge success time or discharge failure time recorded by the recording unit 104 described later, and is updated as necessary.

[0023] FIG. 2 shows a current discharge path (arrows in FIG. 2) in the diagnostic discharge process performed by the discharge processing unit 101. The current is discharged to the first in-vehicle device 21 via the DCDC converter (DDC) 33, and the current is discharged to the second in-vehicle device 22 via the second switch 32. FIG. 3 shows the change in the outflow current and output voltage of the second battery 12 during diagnostic discharge. As shown in FIG. 3, during diagnostic discharge, the DCDC converter (DDC) 33 controls the second battery 12 so that a constant current Ia flows out continuously for a first time. This constant value Ia is appropriately set based on a current (backup actual current) that must be continuously supplied from the second battery 12 to the second in-vehicle device 22 during backup process for a first time (for example, 15 seconds). This diagnostic discharge process may be repeated once or twice more depending on the determination result of the determination unit 103 described later.

[0024] The acquisition unit 102 acquires physical quantities indicating the state of the second battery 12 while the discharge processing unit 101 is performing the diagnostic discharge process. The physical quantities indicating the state of the second battery 12 can be acquired from a detection device such as a sensor (not shown) mounted on the vehicle. Examples of the physical quantities indicating the state of the second battery 12 include voltage, current, and temperature. In this embodiment, the acquisition unit 102 acquires the current (flow current) discharged from the second battery 12 and the output voltage as the physical quantities. The acquisition unit 102 can also acquire the internal resistance and the amount of stored electricity (SOC: State Of Charge) from the voltage, current, and temperature.

[0025] The determination unit 103 determines whether or not the deterioration of the second battery 12 can be diagnosed based on the physical quantity indicating the state of the second battery 12 acquired by the acquisition unit 102. The deterioration diagnosis of the second battery 12 is performed, for example, based on whether or not the power that can be supplied by the second battery 12, which is derived from the outflow current and output voltage of the second battery 12 obtained by the diagnostic discharge process, satisfies the power required as a backup power source for the first battery 11. For this reason, the accuracy of the outflow current and output voltage of the second battery 12 acquired by the acquisition unit 102 is required. The determination unit 103 determines whether or not the deterioration diagnosis of the second battery 12 can be performed based on whether or not the accuracy of the outflow current and output voltage of the second battery 12 acquired by the acquisition unit 102 is high. The accuracy of the outflow current and output voltage of the second battery 12 will be described later.

[0026] When the determination unit 103 determines that the deterioration of the second battery 12 can be diagnosed, the recording unit 104 records the time from a predetermined reference timing (first timing) to the timing (second timing) at which the deterioration diagnosis of the second battery 12 is performed as the successful discharge time. FIG. 4 shows an example of the successful discharge time recorded by the recording unit 104. In the example of FIG. 4, the number of successful discharge times is cumulatively recorded for each arbitrarily determined time division. In this case, the timing at which the discharge processing unit 101 performs the deterioration diagnosis of the second battery 12 is determined based on the successful discharge time (adopted) surrounded by the dotted line in FIG. 4.

[0027] Furthermore, when the determination unit 103 determines that the second battery 12 cannot be diagnosed for deterioration, the recording unit 104 may record the time from the reference timing (first timing) to the timing (second timing) at which the deterioration diagnosis of the second battery 12 is performed as the discharge failure time. FIG. 5 shows an example of the discharge failure time recorded by the recording unit 104. In the example of FIG. 5, the number of discharge failure times is cumulatively recorded for each arbitrarily determined time division. In this case, the timing of the deterioration diagnosis of the second battery 12 performed by the discharge processing unit 101 is determined based on the time other than the discharge failure times (not adopted) surrounded by the dotted line in FIG. 5.

[0028] The successful discharge time and failed discharge time recorded by the recording unit 104 are reset, for example, when the second battery 12 or an electronic control unit (ECU) that consumes current is replaced.

[0029] When the determination unit 103 determines that the second battery 12 can be diagnosed for deterioration, the diagnosis unit 105 performs deterioration diagnosis of the second battery 12 based on the physical quantities (flow current and output voltage) indicating the state of the second battery 12 acquired by the acquisition unit 102. In this deterioration diagnosis, it is diagnosed whether the second battery 12 is in a state where it can back up the first battery 11 when the first battery 11 fails.

[0030] Note that a part or all of the above-mentioned battery diagnostic device 100 may be configured as an electronic control unit (ECU) that typically includes a processor such as a microcomputer, a memory, an input / output interface, etc. This electronic control unit can realize a part or all of the functions of the discharge processing unit 101, the acquisition unit 102, the determination unit 103, the recording unit 104, and the diagnosis unit 105 by the processor reading and executing a program stored in the memory.

[0031] [control] Next, the control executed by the battery diagnostic device 100 according to this embodiment will be described with further reference to Fig. 6A and Fig. 6B. Fig. 6A and Fig. 6B are flow charts for explaining the procedure of the diagnostic process (battery diagnostic process) regarding the deterioration of the second battery 12 executed by each component of the battery diagnostic device 100 during manual driving. The process of Fig. 6A and the process of Fig. 6B are connected by connectors X and Y.

[0032] The battery diagnosis process illustrated in Figures 6A and 6B is started when the vehicle ignition is turned on (IG-ON). The battery diagnosis process ends when the vehicle is switched from manual driving to automatic driving.

[0033] (Step S601) The discharge processing unit 101 judges whether or not the timing (second timing) for performing the diagnostic discharge processing has arrived. This second timing can be determined, for example, by any of the following methods, with the time when the vehicle ignition is turned on (IG-ON) being the reference timing (first timing). Note that the reference timing is not limited to IG-ON, and any timing that serves as an absolute reference can be determined.

[0034] The first method is a method in which the second timing is determined to be a point after the first timing has passed since the successful discharge time that has been recorded the maximum number of times among the successful discharge times recorded by the recording unit 104. As in this first method, by determining the second timing according to a time when many diagnostic discharge processes have been successful in the past, it is possible to increase the probability that the current diagnostic discharge process will be successful.

[0035] The second technique is a technique in which the second timing is determined as a time point when the average of the successful discharge times recorded by the recording unit 104 has elapsed from the first timing. As in this second technique, by determining the second timing according to the average of the times when the diagnostic discharge process was successful in the past, it is possible to increase the probability that the current diagnostic discharge process will be successful.

[0036] The third method is a method in which the second timing is any time from the first timing other than the discharge failure time recorded by the recording unit 104. By determining the second timing from a time excluding times when the diagnostic discharge process has previously failed, as in this third method, it is possible to reduce the probability of failure of the current diagnostic discharge process and increase the probability of success.

[0037] The process waits until the timing (second timing) to perform the diagnostic discharge process comes (S601, No), and when the timing (second timing) comes (S601, Yes), the process proceeds to step S602.

[0038] (Step S602) The discharge processing unit 101 performs a first diagnostic discharge process. As described above, the diagnostic discharge is performed by passing a constant current Ia from the second battery 12 to the first in-vehicle device 21 and the second in-vehicle device 22 (FIG. 2) for a first time period (FIG. 3). While this diagnostic discharge is being performed, the acquisition unit 102 appropriately acquires physical quantities of the second battery 12. After the first diagnostic discharge process is performed, the process proceeds to step S603.

[0039] (Step S603) The determination unit 103 determines whether or not it is possible to diagnose deterioration of the second battery 12. This determination is made based on the physical quantity of the second battery 12 acquired by the acquisition unit 102, for example, based on whether or not the following condition is satisfied: (1) The average value of the drain current of the second battery 12 during the first hour, which is the discharging period, is not equal to or greater than the first threshold value. (2) The current flowing out of the second battery 12 at the end of the discharge after the first time period has elapsed (the measurement point in FIG. 3) is not equal to or greater than the second threshold value.

[0040] Condition (1) is intended to assume a situation in which the second in-vehicle device 22 generates a current demand that is too large to be absorbed by the control of the DCDC converter 33. In such a situation, the current supplied from the second battery 12 to the second in-vehicle device 22 during diagnostic discharge becomes unstable, and the physical quantity of the second battery 12 acquired by the acquisition unit 102 cannot correctly diagnose the deterioration of the battery. For this reason, the determination of condition (1) is performed. The first threshold is appropriately set based on the constant current Ia flowing during diagnostic discharge and the actual backup current.

[0041] Condition (2) is intended to assume a situation where, even when the above condition (1) is satisfied, the drain current of the second battery 12 changes significantly at the end of discharge after the first time has elapsed. In such a situation, the available power supply (= drain current × output voltage) of the second battery 12 derived from the physical quantity of the second battery 12 acquired by the acquisition unit 102 fluctuates, and the deterioration of the battery cannot be correctly diagnosed. For this reason, the determination of condition (2) is performed. The second threshold is appropriately set based on the supply power required of the second battery 12 as a backup power source for the first battery 11.

[0042] If any one of these conditions (1) and (2) is not satisfied, that is, if the average value of the current flowing out of the second battery 12 in the first hour is equal to or greater than the first threshold value, or if the current flowing out of the second battery 12 at the end of discharging after the first hour has elapsed is equal to or greater than the second threshold value, the judgment unit 103 judges that battery deterioration diagnosis is impossible.

[0043] If the deterioration diagnosis of the second battery 12 is possible (S603, YES), the process proceeds to step S614. On the other hand, if the deterioration diagnosis of the second battery 12 is not possible (S603, NO), the process proceeds to step S604.

[0044] (Step S604) The recording unit 104 records the time from the first timing (the time when the vehicle IG-ON) to the start of the first diagnostic discharge process (the second timing in this case) as the discharge failure time. When the discharge failure time is recorded, the process proceeds to step S605.

[0045] (Step S605) The discharge processing unit 101 charges the second battery 12 in preparation for the second diagnostic discharge process. This charging is performed by the discharge processing unit 101 instructing the control unit 60 to control the DCDC converter 33. Once the second battery 12 has been charged, the process proceeds to step S606.

[0046] (Step S606) The discharge processing unit 101 judges whether the amount of stored power in the second battery 12 has reached a predetermined amount of stored power (first amount of stored power). This judgment is made in preparation for the case where a third diagnostic discharge process is subsequently performed after the second diagnostic discharge process. That is, the amount of stored power is increased in advance so that the amount of stored power in the second battery 12 does not decrease excessively even if diagnostic discharge is performed twice in succession. Charging is continued until the amount of stored power in the second battery 12 reaches the first amount of stored power (S606, No), and when the amount of stored power in the second battery 12 reaches the first amount of stored power (S606, Yes), the process proceeds to step S607.

[0047] (Step S607) The discharge processing unit 101 performs a second diagnostic discharge process (re-diagnosis discharge process). The diagnostic discharge is as described above. In order to stabilize the flow current of the second battery 12, it is desirable to perform the second diagnostic discharge process during a period when there is no large current demand from the second in-vehicle device 22, which occurred during the first diagnostic discharge process. The timing of this execution may be determined based on the discharge success time or discharge failure time recorded by the recording unit 104. While this diagnostic discharge is being performed, the acquisition unit 102 appropriately acquires the physical quantity of the second battery 12. After the second diagnostic discharge process is performed, the process proceeds to step S608.

[0048] (Step S608) The determination unit 103 determines whether or not it is possible to diagnose deterioration of the second battery 12. This determination is as described above. If it is possible to diagnose deterioration of the second battery 12 (S608, Yes), the process proceeds to step S614. On the other hand, if it is not possible to diagnose deterioration of the second battery 12 (S608, No), the process proceeds to step S609.

[0049] (Step S609) The recording unit 104 records the time from the first timing (the time when the IG-ON of the vehicle is turned on) to the start of the second diagnostic discharge process as the discharge failure time. When the discharge failure time is recorded, the process proceeds to step S610.

[0050] (Step S610) The discharge processing unit 101 judges whether a predetermined time (second time) has elapsed since the end of the second diagnostic discharge process. This judgment is made in preparation for the implementation of the third diagnostic discharge process. That is, since there is a possibility that polarization has occurred in the second battery 12 immediately after the discharge at a constant current (CC discharge) has been performed by the second diagnostic discharge process, this judgment is made to eliminate the influence of polarization. Therefore, the predetermined time (second time) is set to a sufficient time until the polarization of the second battery 12 is eliminated. Time measurement continues until the predetermined time has elapsed (S610, No), and once the predetermined time has elapsed (S610, Yes), the process proceeds to step S611.

[0051] (Step S611) The discharge processing unit 101 performs a third diagnostic discharge process (re-diagnosis discharge process). The diagnostic discharge is as described above. The reason for performing the third diagnostic discharge process following the second diagnostic discharge process is that even if a large current demand occurs due to the second in-vehicle device 22 in the second diagnostic discharge process, it is highly likely that such a demand will not occur in the third diagnostic discharge process. While this diagnostic discharge is being performed, the acquisition unit 102 appropriately acquires physical quantities of the second battery 12. Once the third diagnostic discharge process has been performed, the process proceeds to step S612.

[0052] (Step S612) The determination unit 103 determines whether or not it is possible to diagnose deterioration of the second battery 12. This determination is as described above. If it is possible to diagnose deterioration of the second battery 12 (S612, Yes), the process proceeds to step S614. On the other hand, if it is not possible to diagnose deterioration of the second battery 12 (S612, No), the process proceeds to step S613.

[0053] (Step S613) The recording unit 104 records the time from the first timing (the time when the vehicle IG-ON is turned on) to the start of the third diagnostic discharge process as the discharge failure time. When the discharge failure time is recorded, the process proceeds to step S616.

[0054] (Step S614) The recording unit 104 records the time from the first timing (the time when the vehicle IG-ON) to the start of the diagnostic discharge process as the successful discharge time. In this process, if it is determined that the deterioration diagnosis of the second battery 12 is possible in the first diagnostic discharge process (S603, Yes), the time from the first timing to the start of the first diagnostic discharge process (second timing) is recorded as the successful discharge time. If it is determined that the deterioration diagnosis of the second battery 12 is possible in the second diagnostic discharge process (S608, Yes), the time from the first timing to the start of the second diagnostic discharge process is recorded as the successful discharge time. If it is determined that the deterioration diagnosis of the second battery 12 is possible in the third diagnostic discharge process (S612, Yes), the time from the first timing to the start of the third diagnostic discharge process is recorded as the successful discharge time. After the successful discharge time is recorded, the process proceeds to step S615.

[0055] (Step S615) The diagnosis unit 105 performs a diagnosis regarding the deterioration of the second battery 12. This deterioration diagnosis is performed based on the physical quantity of the second battery 12 acquired by the acquisition unit 102, depending on whether the power that can be supplied by the second battery 12 is sufficient to secure a backup power when the first battery 11 fails. More specifically, if it is determined in the first diagnostic discharge process that the deterioration diagnosis of the second battery 12 is possible (S603, Yes), the physical quantity of the second battery 12 acquired by the acquisition unit 102 during the first diagnostic discharge is used for the diagnosis. If it is determined in the second diagnostic discharge process that the deterioration diagnosis of the second battery 12 is possible (S608, Yes), the physical quantity of the second battery 12 acquired by the acquisition unit 102 during the second diagnostic discharge is used for the diagnosis. If it is determined in the third diagnostic discharge process that the deterioration diagnosis of the second battery 12 is possible (S612, Yes), the physical quantity of the second battery 12 acquired by the acquisition unit 102 during the third diagnostic discharge is used for the diagnosis. When the deterioration state of the second battery 12 is diagnosed, this battery diagnosis process ends.

[0056] (Step S616) The diagnosis unit 105 determines that the condition of the second battery 12 is abnormal because it has been determined in three diagnostic discharge processes that deterioration diagnosis of the second battery 12 is not possible. If it is determined that the condition of the second battery 12 is abnormal, this battery diagnosis process ends.

[0057] <Actions and Effects> As described above, according to the battery diagnostic device 100 according to an embodiment of the present disclosure, if the initial diagnostic discharge process (first diagnostic discharge) fails to obtain a physical quantity with sufficient accuracy to perform degradation diagnosis of the second battery 12, the diagnostic discharge process (second or third diagnostic discharge) is repeatedly performed multiple times to obtain the physical quantity. This process increases the likelihood of obtaining a highly accurate physical quantity, thereby increasing the opportunities to perform degradation diagnosis of the second battery 12.

[0058] Furthermore, according to the battery diagnostic device 100 of this embodiment, the timing to perform the first diagnostic discharge process (first diagnostic discharge) is determined based on the past successful or unsuccessful discharge times. This allows the battery diagnostic process to be performed at a time when the diagnostic discharge process is highly likely to be successful, improving the accuracy of battery diagnosis.

[0059] Although one embodiment of the present disclosure has been described above, the present disclosure can be understood as a battery diagnostic device, a method executed by a battery diagnostic device having a processor and a memory, a program for executing the method, a computer-readable non-transitory storage medium storing the program, and a vehicle equipped with a battery diagnostic device. [Industrial Applicability]

[0060] The battery diagnostic device and the like disclosed herein can be used to diagnose the condition of a battery mounted in a vehicle. [Explanation of symbols]

[0061] 11 Battery No. 1 12 Second Battery 21 1st in-vehicle equipment 22 2nd in-vehicle equipment 30 Connection switch 31 First Switch 32 Second Switch 33 DC-DC converter 40 Generator 51~53 Power Lines 60 Control section 100 Battery diagnostic device 101 Discharge processing section 102 Acquisition Department 103 Judgment section 104 Recording Section 105 Diagnostic Department

Claims

1. A battery diagnostic device for diagnosing the state of a battery mounted on a vehicle, a discharge processing unit that performs diagnostic discharge from the battery to a predetermined in-vehicle device at a second timing that is a predetermined time after the first timing; an acquisition unit that acquires a physical quantity indicating a state of the battery during the diagnostic discharge; a determination unit that determines whether or not a deterioration diagnosis of the battery is possible based on the physical quantity; a recording unit that records the predetermined time as a successful discharge time when it is determined that the deterioration diagnosis of the battery is possible; a diagnosis unit that, when it is determined that deterioration diagnosis of the battery is possible, performs deterioration diagnosis of the battery based on the physical quantity.

2. The battery diagnostic device according to claim 1 , wherein the discharge processing unit performs the diagnostic discharge at the second timing, the predetermined time being set to the time when the successful discharge time that results in the maximum number of times recorded in the recording unit is the largest.

3. The battery diagnostic device according to claim 1 , wherein the discharge processing unit performs the diagnostic discharge at the second timing, the second timing being set to an average value of the successful discharge times recorded in the recording unit as the predetermined time.

4. When it is determined that the deterioration diagnosis of the battery is impossible, the recording unit records the predetermined time as a discharge failure time, The battery diagnostic device according to claim 1 , wherein the discharge processing unit performs the diagnostic discharge at the second timing, the predetermined time being a time other than the discharge failure time recorded in the recording unit.

5. 5. The battery diagnosis device according to claim 4, wherein, when it is determined that deterioration diagnosis of the battery is impossible, the discharge processing unit performs a re-diagnosis discharge from the battery to a specified vehicle-mounted device at a timing when a time other than the discharge failure time recorded in the recording unit has elapsed from the first timing.

6. 6. The battery diagnostic device according to claim 1, wherein the first timing is a timing when an ignition of the vehicle is turned on.

7. A method executed by a computer of a battery diagnostic device for diagnosing the condition of a battery mounted on a vehicle, comprising: performing diagnostic discharge from the battery to a predetermined in-vehicle device at a second timing when a predetermined time has elapsed from the first timing; acquiring a physical quantity indicative of the state of the battery during the diagnostic discharge; determining whether or not a deterioration diagnosis of the battery is possible based on the physical quantity; If it is determined that the deterioration diagnosis of the battery is possible, recording the predetermined time as a successful discharge time; and when it is determined that deterioration diagnosis of the battery is possible, performing deterioration diagnosis of the battery based on the physical quantity.

8. A program to be executed by a computer of a battery diagnostic device that diagnoses the state of a battery mounted on a vehicle, performing diagnostic discharge from the battery to a predetermined in-vehicle device at a second timing when a predetermined time has elapsed from the first timing; acquiring a physical quantity indicative of the state of the battery during the diagnostic discharge; determining whether or not a deterioration diagnosis of the battery is possible based on the physical quantity; If it is determined that the deterioration diagnosis of the battery is possible, recording the predetermined time as a successful discharge time; and when it is determined that deterioration diagnosis of the battery is possible, performing deterioration diagnosis of the battery based on the physical quantity.

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