Diagnostic methods

Abstract

To improve accuracy of battery deterioration determination.SOLUTION: A diagnostic method provided herein involves making a computer perform deterioration diagnosis of a dummy battery through which a mirror current flows based on a current flowing through a battery used as a power source of a driving motor, and perform reversible deterioration diagnosis on the dummy battery based on a usage mode of the battery if the dummy battery is determined to be deteriorated in the deterioration diagnosis.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a diagnostic method, and more particularly to a technique for diagnosing the deterioration of a battery installed in a vehicle. [Background technology]

[0002] A system has been proposed in which a battery that serves as a power source for a vehicle's driving motor is connected in series with a dummy battery, and the degree of deterioration of the battery is determined by measuring the degree of deterioration of the dummy battery (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-509593 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery that powers the traction motor may experience a temporary capacity drop when used at low temperatures and with a high load current, for example. If a battery degradation diagnosis is performed when a temporary capacity drop occurs, the battery may be determined to be degraded even though it is not actually degraded.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to improve the accuracy of determining battery deterioration. [Means for solving the problem]

[0006] In a diagnostic method according to the present invention, a computer performs a deterioration diagnosis of a dummy battery through which a mirror current based on a current flowing in a battery used as a power source for a driving motor flows, and if the deterioration diagnosis determines that the dummy battery has deteriorated, a reversible deterioration diagnosis of the dummy battery is performed based on a usage state of the battery, and if the reversible deterioration diagnosis determines that the dummy battery has reversibly deteriorated, a deteriorated electrode diagnosis is performed based on a slope of a charge / discharge curve of the dummy battery. If the deterioration electrode diagnosis determines that the negative electrode is deteriorated, the dummy battery is refresh-discharged, and if the deterioration electrode diagnosis determines that the positive electrode is deteriorated, the dummy battery is refresh-charged. . [Effects of the Invention]

[0007] According to the present invention, it is possible to improve the accuracy of determining battery deterioration. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a diagnostic system. [Figure 2] FIG. 1 is a diagram illustrating a configuration of a vehicle. [Figure 3] FIG. 2 is a diagram illustrating the configuration of a diagnostic device. [Figure 4] FIG. 1 is a diagram illustrating reversible deterioration of a battery. [Figure 5] 10 is a flowchart showing the flow of a diagnostic process. DETAILED DESCRIPTION OF THE INVENTION

[0009] <1. Overview of diagnostic system configuration> 1 is a diagram illustrating the configuration of a diagnostic system 1. As shown in FIG.

[0010] The vehicle 10 is a hybrid vehicle driven by an engine and a traction motor, or an electric vehicle driven only by a traction motor. In the following, an example will be described in which the vehicle 10 is an electric vehicle driven only by a traction motor.

[0011] As will be described in detail later, the diagnostic device 20 indirectly diagnoses the deterioration of the battery 11 (see FIG. 2) provided in the vehicle 10 by diagnosing the dummy battery 14.

[0012] <2. Vehicle configuration> Fig. 2 is a diagram illustrating the configuration of the vehicle 10. In Fig. 2, electrical circuits are indicated by solid lines, and signal circuits or data communication circuits are indicated by dashed lines.

[0013] As shown in FIG. 2, the vehicle 10 includes a battery 11, a traction motor 12, a BCU 13, a dummy battery 14, an ammeter 15, a thermometer 16, and a communication unit 17.

[0014] The battery 11 is, for example, a lithium ion secondary battery, and is used as a power source for the driving motor 12. The battery 11 has a plurality of cells (several tens of cells), and has a rated output voltage of approximately several hundred volts. The battery 11 can be charged from an external power supply device.

[0015] The traction motor 12 is a motor provided as a drive source for the wheels of the vehicle 10, and is driven by power supplied from the battery 11 via an inverter (not shown). The traction motor 12 can also function as a generator when the vehicle 10 is decelerating. The power generated by the traction motor 12 is regenerated and sent to the battery 11 via the inverter.

[0016] The BCU 13 is configured with a microcomputer having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The BCU 13 controls the power supply in the vehicle 10, i.e., controls the battery 11 and the dummy battery 14, by the CPU expanding a program stored in the ROM into the RAM and executing it.

[0017] The BCU 13 also includes a storage unit made of a nonvolatile memory or the like, and is capable of storing various data in the storage unit. The BCU 13 is also configured to be able to calculate the SOC (State Of Charge) of each of the battery 11 and the dummy battery 14. Note that the SOC can be calculated using various known methods, such as a method using an OCV-SOC curve that indicates the relationship between the OCV (Open Circuit Voltage) and the SOC, or a method using an integrated value of current during charging and discharging, and therefore detailed explanations thereof will be omitted here.

[0018] The dummy battery 14 is a lithium ion secondary battery separate from the battery 11, and is provided as a battery for diagnostic purposes. The dummy battery 14 is a scaled-down version of the battery 11, and has one or more cells (several tens of cells), with a rated output voltage of about 5V.

[0019] The dummy battery 14 is configured as a battery in a separate housing from the battery 11. For example, the battery 11 is attached relatively firmly with a plurality of bolts or the like under the floor of the passenger compartment of the vehicle 10. In contrast, the dummy battery 14 is attached to a predetermined position within the vehicle 10 via an attachment / detachment mechanism such as a hook so that it can be removed relatively easily.

[0020] The ammeter 15 measures the current value of the current charged and discharged from the battery 11 and outputs the measured current value to the BCU 13 .

[0021] The thermometer 16 measures the temperature of the battery 11 or the ambient temperature of the battery 11, and outputs the measured temperature to the BCU 13. The ambient temperature is the temperature of the space in which the battery 11 is installed, that is, the ambient temperature of the battery 11.

[0022] The communication unit 17 is connected to the BCU 13 and can be connected to a vehicle diagnosis terminal (not shown) by wire. The communication unit 17 transmits and receives data between the BCU 13 and the vehicle diagnosis terminal.

[0023] The BCU 13 constantly stores usage status data indicating the usage status of the battery 11. The usage status of the battery 11 refers to the state of the battery 11 when it is being used, such as the environment in which the battery 11 is placed and how the battery 11 is being used. Specifically, the BCU 13 stores the current value measured by the ammeter 15, the temperature measured by the thermometer 16, and the SOC as usage status data in the storage unit at predetermined intervals.

[0024] Furthermore, the BCU 13 generates a mirror current based on the current flowing through the battery 11. Specifically, the BCU 13 generates the mirror current based on the current value of the current flowing through the battery 11 measured by the ammeter 15. The "mirror current" here refers to a current that changes in conjunction with the current flowing through the battery 11 in order to simulate the usage state of the battery 11 in the dummy battery 14.

[0025] As an example, it is conceivable that the mirror current is generated so that the temperature of the battery 11 and the temperature of the dummy battery 14 become equal to each other with respect to the temperature of the battery 11 caused by Joule heat. Specifically, BCU13: (Battery 11 current) 2 × (heat capacity of battery 11) = (current of dummy battery 14) 2 × (Heat capacity of dummy battery 14) A mirror current is generated so as to satisfy the condition:

[0026] As another example, the mirror current may be generated so that the SOC of the battery 11 and the SOC of the dummy battery 14 are equal. Specifically, BCU13: (Current of battery 11) / (Initial capacity of battery 11) = (current of dummy battery 14) / (initial capacity of dummy battery 14) A mirror current is generated so as to satisfy the condition:

[0027] The mirror current may also be generated by applying a coefficient according to the difference in capacity between the battery 11 and the dummy battery 14. Specifically, if the size and capacity of the cells of the dummy battery 14 are 1 / 10 of those of the cells of the battery 11, the BCU 13 generates a mirror current with a current value 1 / 10 of the current value of the current flowing through the battery 11.

[0028] In this way, the mirror current may be any current generated so that the usage state of the battery 11 is simulated in the dummy battery 14.

[0029] The BCU 13 causes the generated mirror current to flow to the dummy battery 14. By causing a mirror current of the current flowing to the battery 11 to flow to the dummy battery 14, the usage state of the battery 11 is reproduced in the dummy battery 14. In other words, the BCU 13 causes the dummy battery 14 to simulate the deterioration state of the battery 11.

[0030] <3. Configuration of diagnostic equipment> Fig. 3 is a diagram illustrating the configuration of the diagnostic device 20. In Fig. 3, electric circuits are indicated by solid lines, and signal circuits or data communication circuits are indicated by dashed lines.

[0031] As shown in FIG. 3, the diagnostic device 20 includes a control unit 21, a charger / discharger 22, a heater 23, a voltmeter 24, an ammeter 25, a thermometer 26, and a communication unit 27.

[0032] The control unit 21 is configured with, for example, a microcomputer having a CPU, a ROM, and a RAM, and controls each part of the diagnostic device 20 by the CPU expanding a program stored in the ROM into the RAM and executing it.

[0033] The charger / discharger 22 charges and discharges the dummy battery 14 removed from the vehicle 10 under the control of the control unit 21.

[0034] The heater 23 heats the dummy battery 14 under the control of the control unit 21 .

[0035] The voltmeter 24 measures the voltage value of the dummy battery 14 and outputs the measured voltage value to the control unit 21 .

[0036] The ammeter 25 measures the current value of the current charged and discharged from the dummy battery 14 and outputs the measured current value to the control unit 21.

[0037] The thermometer 26 measures the temperature of the dummy battery 14 or the temperature around the dummy battery 14, and outputs the measured temperature to the control unit 21.

[0038] The communication unit 17 is connected to the BCU 13 and also connected to a vehicle diagnosis terminal (not shown) by wire. The communication unit 17 transmits and receives data between the BCU 13 and the vehicle diagnosis terminal.

[0039] When the dummy battery 14 is set in the diagnostic device 20, the control unit 21 first diagnoses the deterioration of the dummy battery 14. For clarity, the deterioration diagnosis here means comparing at least a reference evaluation index value with an actually measured evaluation index value for an evaluation index relating to the deterioration state of the battery. Although a known method may be used to diagnose battery deterioration, an example will be given here in which diagnosis is performed based on the capacity maintenance rate of the battery.

[0040] In the deterioration diagnosis based on the capacity maintenance rate, the control unit 21 calculates the capacity maintenance rate Rc (%) of the dummy battery 14 as shown in the following [Equation 1]. “Capacity maintenance rate Rc= Current full charge capacity (Ah) / Reference full charge capacity x 100 ...[Formula 1] The reference full charge capacity is a full charge capacity that is determined in advance to be used as a reference, such as a full charge capacity measured at the time of shipping from the factory (initial full charge capacity of the dummy battery 14). The full charge capacity in [Equation 1] is calculated by the following [Equation 2]. Full charge capacity (Ah) = Accumulated charging current (Ah) / (SOC after charging - SOC before charging) x 100 ...[Formula 2]

[0041] The SOC of the dummy battery 14 can be calculated based on the voltage value measured by the voltmeter 24.

[0042] Here, the charger / discharger 22 charges the dummy battery 14. When the dummy battery 14 is fully charged, i.e., when charging of the dummy battery 14 is completed, the control unit 21 calculates the capacity maintenance rate Rc described above and performs a deterioration diagnosis of the dummy battery 14 based on the capacity maintenance rate Rc.

[0043] Then, as a deterioration diagnosis, the control unit 21 determines whether or not the capacity maintenance rate Rc is equal to or greater than a predetermined capacity threshold value Th. Note that the capacity threshold value Th is set to, for example, a capacity maintenance rate at which the battery 11 can be reused.

[0044] If the capacity maintenance rate Rc is equal to or greater than the capacity threshold value Th, it is determined that the dummy battery 14 has not deteriorated, i.e., the battery 11 has not deteriorated and can be reused. On the other hand, if the capacity maintenance rate Rc is less than the capacity threshold value Th, it is determined that the dummy battery 14 has deteriorated, i.e., the battery 11 has deteriorated and cannot be reused.

[0045] 4 is a diagram illustrating reversible deterioration of the battery 11. However, reversible deterioration occurs in the battery 11 when a high load current is frequently applied at low temperatures, such as when frequent slip and grip occurs on icy mountain roads.

[0046] Reversible degradation is a phenomenon in which charge is concentrated mainly on the surface of the negative electrode, making it difficult to store electricity inside the battery 11, resulting in a temporary decrease in capacity and an increase in resistance of the battery 11. This type of reversible degradation gradually resolves over time.

[0047] For example, as shown in Fig. 4, let us assume that a capacity decrease, which is one type of reversible degradation, occurs in battery 11 at time T1. Then, let us assume that the capacity decrease of battery 11 is resolved over time, and that the capacity decrease is completely resolved at time T2.

[0048] In such a case, suppose that the dummy battery 14 is removed from the vehicle 10 between time T1 and time T2 and a deterioration diagnosis is performed. In this case, the dummy battery 14 is in the same usage state as the battery 11, and therefore reversible deterioration has occurred in the same way as the battery 11.

[0049] Therefore, if a deterioration diagnosis is performed on the dummy battery 14 between time T1 and time T2, the capacity maintenance rate of the dummy battery 14 will be determined to be less than the capacity threshold Th at which the battery 11 is deemed unreusable, for example. That is, the battery 11 will be erroneously determined to be unreusable due to reversible deterioration.

[0050] Therefore, when the control unit 21 determines that the dummy battery 14 has deteriorated in the deterioration diagnosis, it performs a reversible deterioration diagnosis to determine whether the dummy battery 14 may have deteriorated reversibly based on the usage state of the battery 11.

[0051] Specifically, the control unit 21 acquires usage state data from the vehicle 10 via the vehicle diagnosis terminal. Then, the control unit 21 refers to a preset frequency map for the acquired usage state data and determines whether there is a possibility that the dummy battery 14 has undergone reversible deterioration.

[0052] The frequency map defines the ranges in which reversible degradation can occur for three parameters: current value, temperature, and SOC. The control unit 21 counts the number of times that a combination of current value, temperature, and SOC stored in the usage state data falls within the ranges defined in the frequency map. If the counted value is equal to or greater than a preset count threshold, the control unit 21 determines that there is a possibility that the dummy battery 14 has undergone reversible degradation.

[0053] When it is determined that there is a possibility that the dummy battery 14 has reversibly deteriorated, the control unit 21 performs a deteriorated electrode diagnosis to determine which electrodes in the dummy battery 14 have deteriorated.

[0054] Specifically, the control unit 21 controls the charger / discharger 22 to charge and discharge the dummy battery 14, and calculates a charge / discharge curve (capacity and voltage) based on the voltage value measured by the voltmeter 24 and the current value measured by the ammeter 25 during this period. The control unit 21 also calculates a dQ / dV curve by differentiating the charge / discharge curve.

[0055] It is known that it is possible to estimate whether a battery is deteriorating due to positive electrode degradation or negative electrode degradation based on the dQ / dV curve, i.e., the slope of the charge / discharge curve. Specifically, since the position (capacity) at which the charge / discharge curve suddenly changes during charging or discharging differs between positive electrode degradation and negative electrode degradation, it is possible to estimate whether a battery is deteriorating due to positive electrode degradation or negative electrode degradation based on the position (capacity) at which the charge / discharge curve suddenly changes.

[0056] Therefore, the control unit 21 determines whether the deterioration is caused by the positive electrode or the negative electrode based on the calculated dQ / dV curve.

[0057] When the negative electrode of the dummy battery 14 is deteriorated, lithium ions are unevenly accumulated in the negative electrode of the dummy battery 14, and therefore the control unit 21 controls the charger / discharger 22 to refresh discharge the dummy battery 14. Note that refresh discharge refers to forcibly discharging the electricity accumulated in the dummy battery 14.

[0058] Furthermore, while the dummy battery 14 is being refresh-discharged, the control unit 21 causes the heater 23 to heat the dummy battery 14 to, for example, about 60° C. This allows the dummy battery 14 to respond quickly.

[0059] On the other hand, if the positive electrode of the dummy battery 14 has deteriorated, lithium ions are being released unevenly from the positive electrode of the dummy battery 14, and so the control unit 21 controls the charger / discharger 22 to refresh charge the dummy battery 14. Note that refresh charging refers to forcibly charging the dummy battery 14.

[0060] Furthermore, while the control unit 21 is refreshingly charging the dummy battery 14, the control unit 21 causes the heater 23 to heat the dummy battery 14 to, for example, about 60° C. This allows the dummy battery 14 to respond quickly.

[0061] In this way, the control unit 21 recovers the dummy battery 14 from reversible deterioration by performing refresh discharge or refresh charge depending on the deteriorated electrodes of the dummy battery 14.

[0062] Thereafter, the control unit 21 again performs a deterioration diagnosis on the dummy battery 14. If the dummy battery 14 has reversibly deteriorated, it is determined that the capacity of the dummy battery 14 has recovered and that the battery 14 is not deteriorated. In other words, it is determined that the battery 14 is reusable.

[0063] On the other hand, if the dummy battery 14 has not reversibly deteriorated, the capacity of the dummy battery 14 will not recover and it will be determined that the battery 11 is again deteriorated. In other words, it will be determined that the battery 11 is not reusable.

[0064] <4. Diagnostic process flow> Fig. 5 is a flowchart showing the flow of the diagnostic process. The process shown in Fig. 5 is executed by the control unit 21 based on a program stored in a ROM or the like.

[0065] 5, in step S1, the control unit 21 performs a deterioration diagnosis of the dummy battery 14. Specifically, the control unit 21 calculates the capacity maintenance rate using Equation 1. In the following step S2, the control unit 21 determines whether the capacity maintenance rate is equal to or greater than a capacity threshold value Th.

[0066] If the capacity maintenance rate is equal to or greater than the capacity threshold value Th (Yes in step S2), the control unit 21 determines in step S3 that the battery 11 is reusable, and ends the process.

[0067] On the other hand, if the capacity maintenance rate is not equal to or greater than the capacity threshold value Th (No in step S2), in step S4, the control unit 21 determines whether the dummy battery 14 has been refresh-discharged in the following step S9 or refresh-charged in the following step S10. Note that hereinafter, refresh-discharge and refresh-charge are collectively referred to as refresh.

[0068] If the dummy battery 14 has not been refreshed (No in step S4), in step S5 the control unit 21 acquires usage status data from the vehicle 10 via the vehicle diagnosis terminal, and performs a reversible deterioration diagnosis of the dummy battery 14 by referring to the frequency map.

[0069] In the following step S6, the control unit 21 determines whether there is a possibility that the dummy battery 14 has reversibly deteriorated as a result of the reversible deterioration diagnosis in step S5. If there is a possibility that the dummy battery 14 has reversibly deteriorated as a result (Yes in step S6), the control unit 21 performs a deteriorated electrode diagnosis of the dummy battery 14 in step S7. Specifically, the control unit 21 controls the charger / discharger 22 to charge and discharge the dummy battery 14, calculates the charge / discharge curve and dQ / dV curve during this period, and determines whether there is positive electrode deterioration or negative electrode deterioration based on the calculated dQ / dV curve.

[0070] In step S8, the control unit 21 determines whether the negative electrode of the dummy battery 14 has deteriorated as a result of the deterioration electrode diagnosis in step S8. If the result indicates that the negative electrode of the dummy battery 14 has deteriorated (Yes in step S8), the control unit 21 refresh-discharges the dummy battery 14 and heats the dummy battery 14 with the heater 23 in step S9.

[0071] On the other hand, if the dummy battery 14 is not negatively deteriorated (No in step S8), that is, if the dummy battery 14 is positively deteriorated, in step S10, the control unit 21 refresh-charges the dummy battery 14 and heats the dummy battery 14 using the heater 23.

[0072] Then, if the dummy battery 14 is refreshed in step S9 or step S10, the process returns to step S1.

[0073] If the dummy battery 14 has been refreshed (Yes in step S4) and if there is no possibility that the dummy battery 14 has reversibly deteriorated (No in step S6), the control unit 21 determines in step S11 that the battery 11 cannot be reused and terminates the processing.

[0074] <5. Variations> Here, the embodiment is not limited to the specific example described above, and various modified configurations can be adopted. For example, in the above description, the mirror current to be flowed through the dummy battery 14 is generated by software processing using the BCU 13. However, the mirror current can also be generated using an analog circuit such as a current mirror circuit.

[0075] In the above embodiment, the diagnostic device 20 is provided separately from the vehicle 10. However, the diagnostic device 20 may be provided in the vehicle 10, and diagnostic processing may be performed without removing the dummy battery 14.

[0076] In the above embodiment, if it is determined that the dummy battery 14 may be reversibly deteriorated, a refresh discharge or a refresh charge is performed. However, the control unit 21 may perform only heating by the heater 23 without performing a refresh discharge or a refresh charge. Alternatively, the control unit 21 may not perform a refresh discharge or a refresh charge, and may not heat by the heater 23. In such a case, however, in order to recover from the reversible deterioration of the dummy battery 14, it is necessary to wait a longer time than when a refresh discharge or a refresh charge is performed before performing a degradation diagnosis again.

[0077] In the above embodiment, the temperature of the battery 11 is measured by the thermometer 16, but the temperature of the dummy battery 14 may also be measured.

[0078] In the above embodiment, the vehicle 10 is connected to the diagnostic device 20 via a vehicle diagnostic terminal. However, the vehicle 10 and the diagnostic device 20 may be connected by wire or wirelessly, or the usage status data may be uploaded from the vehicle 10 to a cloud and downloaded by the diagnostic device 20.

[0079] In the above embodiment, the control unit 21 performs the deterioration diagnosis based on the capacity maintenance rate of the dummy battery 14. However, the control unit 21 may perform the deterioration diagnosis based on the resistance increase rate.

[0080] In the deterioration diagnosis based on the resistance increase rate, the resistance increase rate Rr (%) shown in the following [Equation 3] is calculated for the dummy battery 14. "Resistance increase rate Rr = most recent battery resistance value (Ω) / reference battery resistance value (Ω) x 100" ...[Formula 3] The battery resistance value in [Equation 3] is calculated by the following [Equation 4]. "Battery resistance = average change in battery current / average change in voltage between both terminals of the battery" ...[Formula 4]

[0081] In this case, the control unit 21 calculates the battery resistance value of the dummy battery 14 using [Equation 4]. That is, while the vehicle 10 is in a running state, the control unit 21 acquires detection information of the current flowing through the dummy battery 14 and the voltage between both terminals over a predetermined period of time, and calculates the battery resistance value of the dummy battery 14 using [Equation 4].

[0082] As with the above-mentioned reference full charge capacity, the reference battery resistance value is a battery resistance value that has been determined in advance to be used as a reference, such as the battery resistance value measured at the time of shipment from the factory (the initial battery resistance value of the dummy battery 14). Then, the control unit 21 determines whether or not the resistance increase rate Rr is equal to or greater than a predetermined threshold value as a deterioration diagnosis.

[0083] <6. Summary of embodiments> As described above, in the diagnostic method of the embodiment, the computer (control unit 21) performs a deterioration diagnosis of the dummy battery 14 through which a mirror current based on the current flowing in the battery 11 used as the power source for the driving motor 12 flows, and if the deterioration diagnosis determines that the dummy battery 14 is deteriorated, a reversible deterioration diagnosis of the dummy battery 14 is performed based on the usage mode of the battery 11. As a result, even if the diagnostic device 20 determines that the dummy battery 14 has deteriorated in the deterioration diagnosis, it can determine whether the dummy battery 14 has deteriorated reversibly, thereby determining whether the capacity of the dummy battery 14 can be recovered. Therefore, diagnostic device 20 can improve the accuracy of determining the deterioration of battery 11.

[0084] Furthermore, if the reversible deterioration diagnosis determines that the dummy battery 14 has reversibly deteriorated, the computer performs a deteriorated electrode diagnosis of the dummy battery 14 . This allows the diagnostic device 20 to determine whether the cause of the reversible deterioration of the dummy battery 14 is deterioration of the positive electrode or deterioration of the negative electrode. Therefore, the diagnostic device 20 can quickly recover from reversible deterioration depending on the deteriorated electrodes of the dummy battery 14.

[0085] In addition, the computer refresh-discharges the dummy battery 14 when the deterioration electrode diagnosis determines that the negative electrode is deteriorated, and refresh-charges the dummy battery 14 when the deterioration electrode diagnosis determines that the positive electrode is deteriorated. This allows the diagnostic device 20 to quickly recover from reversible deterioration depending on the deteriorated electrodes of the dummy battery 14.

[0086] The computer also heats the dummy battery 14 while performing the refresh discharge or refresh charge. This allows the diagnostic device 20 to increase the reaction speed in refreshing discharge or refreshing charge of the dummy battery 14. Therefore, the diagnostic device 20 can quickly recover the dummy battery 14 from reversible deterioration.

[0087] The computer also performs a reversible deterioration diagnosis of the dummy battery 14 based on the current value, temperature, and SOC of the battery 11 or the dummy battery 14. This allows the diagnostic device 20 to determine a usage state where there is a high possibility of reversible deterioration occurring, such as when the battery is used at low temperature and with a high load current. [Explanation of symbols]

[0088] 1 Diagnostic System 10 vehicles 11 Battery 12. Drive motor 13 BCU 14 Dummy Battery 20 Diagnostic Equipment 21 Control Unit 22 Charge / discharge machine 23 Heater

Claims

1. The computer A deterioration diagnosis is performed on a dummy battery through which a mirror current based on the current flowing in a battery used as a power source for a driving motor flows. If it is determined that the dummy battery is deteriorated in the deterioration diagnosis, a reversible deterioration diagnosis is performed on the dummy battery based on a usage state of the battery; When the reversible deterioration diagnosis determines that the dummy battery has reversibly deteriorated, a deteriorated electrode diagnosis is performed based on the slope of a charge / discharge curve of the dummy battery; When it is determined in the deterioration electrode diagnosis that the negative electrode is deteriorated, the dummy battery is refresh-discharged, and when it is determined in the deterioration electrode diagnosis that the positive electrode is deteriorated, the dummy battery is refresh-charged. Diagnostic methods.

2. The dummy battery is heated while the refresh discharge or the refresh charge is being performed. The diagnostic method according to claim 1.

3. In the reversible deterioration diagnosis, three parameters of the dummy battery, namely, current value, temperature, and SOC, are compared with a frequency map in which a range in which reversible deterioration can occur for the three parameters is defined, and if the number of times that the combination of current value, temperature, and SOC of the dummy battery falls within the range defined in the frequency map is equal to or greater than a predetermined number, it is determined that the dummy battery has undergone reversible deterioration. The diagnostic method according to claim 1 or claim 2.

4. The computer A deterioration diagnosis is performed on a dummy battery through which a mirror current based on the current flowing in a battery used as a power source for a driving motor flows. If it is determined that the dummy battery is deteriorated in the deterioration diagnosis, a reversible deterioration diagnosis is performed on the dummy battery based on a usage state of the battery; In the reversible deterioration diagnosis, three parameters of the dummy battery, namely, current value, temperature, and SOC, are compared with a frequency map in which a range in which reversible deterioration can occur for the three parameters is defined, and if the number of times that the combination of current value, temperature, and SOC of the dummy battery falls within the range defined in the frequency map is equal to or greater than a predetermined number, it is determined that the dummy battery has undergone reversible deterioration. Diagnostic methods.

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