Battery management device and method

Abstract

A battery management device and a management method are provided that are capable of preventing erroneous determination of the deterioration level of a battery by taking the temperature of the battery into consideration. [Solution] The battery management device includes an acquisition unit that acquires data on the battery usage history, the battery deterioration level, and the battery temperature, which is the temperature caused by battery deterioration, a first calculation unit that calculates an approximation line representing the relationship between the usage history and the deterioration level according to the battery temperature based on the acquired data, and a judgment unit that judges whether the acquired deterioration level is within an acceptable range with respect to the approximation line.

Description

[Technical field]

[0001] The present disclosure relates to a battery management device and management method. [Background technology]

[0002] In electric vehicles (EVs) and hybrid vehicles, a battery is installed in the vehicle to supply power to the driving power source. The battery gradually deteriorates with repeated use. Also, the deterioration speed may increase depending on the usage conditions of the battery. Therefore, it is known to predict the deterioration degree of the battery based on the usage history of the battery.

[0003] For example, Patent Document 1 discloses predicting the degree of deterioration of a battery from a deterioration curve according to how the battery is used.

[0004] Furthermore, for example, Patent Document 2 discloses a method of correcting the expansion curve and deterioration curve based on the usage history and environmental conditions, and predicting the degree of deterioration of a battery based on the corrected expansion curve and deterioration curve. For example, Patent Document 3 describes an estimation unit that estimates the degree of deterioration of a battery based on at least one of the battery's continuous use time, temperature history, and overcharge / discharge history. It also describes that the degree of deterioration progresses according to the number of times the battery temperature exceeds a predetermined temperature. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-084198 A [Patent Document 2] JP 2020-071035 A [Patent Document 3] JP 2017-159741 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, since the change in the degree of deterioration of a battery depends on the battery temperature, it is preferable to predict the degree of deterioration of a battery based on a deterioration curve that takes into account the battery temperature.

[0007] However, the inventions described in Patent Documents 1 to 3 do not predict the degree of deterioration of the battery based on a deterioration curve that takes into account the relationship between the battery's usage history and the degree of deterioration of the battery according to the battery temperature, and therefore there is a risk of erroneous judgment of the degree of deterioration of the battery.

[0008] An object of the present disclosure is to provide a battery management device and a management method that are capable of preventing erroneous determination of the deterioration level of a battery by taking the temperature of the battery into consideration. [Means for solving the problem]

[0009] In order to achieve the above object, a battery management device according to the present disclosure includes: an acquisition unit that acquires data on a battery usage history, a deterioration level of the battery, and a temperature of the battery, which is a temperature caused by deterioration of the battery; a first calculation unit that calculates an approximation line representing a relationship between the usage history and the deterioration degree according to a temperature of the battery based on the acquired data; a second calculation unit that calculates an average value of the temperature of the battery acquired during a predetermined period; a third calculation unit that calculates a deterioration rate of the battery based on the calculated average value; a determination unit that determines whether the acquired deterioration degree is within an allowable range with respect to the approximation line; Equipped with picture, The first calculation unit calculates the approximation line for the predetermined period based on the calculated deterioration rate, The first calculation unit further calculates a determination reference line for the approximation line based on a temperature of the battery; The determination unit determines whether or not the acquired deterioration degree is within an allowable range with respect to the approximation line, based on the determination reference line.

[0010] The battery management method according to the present disclosure includes: Obtaining data on a battery usage history, a battery deterioration level, and a battery temperature, which is a temperature caused by battery deterioration; calculating an approximation line representing a relationship between the usage history and the deterioration degree according to the temperature of the battery based on the acquired data; Calculating an average value of the temperature of the battery acquired during a predetermined period; Calculating a deterioration rate of the battery based on the calculated average value; calculating the approximation line for the predetermined period based on the calculated deterioration rate; calculating a judgment reference line for the approximation line based on a temperature of the battery; Whether the acquired deterioration degree is within an allowable range with respect to the approximation line is determined. Based on the judgment criteria Make a judgment. Effect of the Invention

[0011] According to the present disclosure, by taking into consideration the temperature of the battery, it is possible to prevent erroneous determination of the deterioration level of the battery. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an example of a battery management device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating an example of accumulated data accumulated in the storage unit. [Figure 3A] FIG. 3A is a diagram showing the relationship between seasons and temperature. [Figure 3B] FIG. 3B shows a scatter plot and an approximation line according to this embodiment. [Figure 4] FIG. 4 is a diagram showing the relationship between the temperature of the battery and the rate of deterioration of the battery. [Diagram 5] FIG. 5 is a diagram showing the relationship between the number of cycles and the SOH. [Figure 6] FIG. 6 shows a scatter diagram and an approximation line according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 1 is a diagram illustrating an example of a battery management device according to an embodiment of the present disclosure. The battery management device according to the present embodiment can be applied to commercial vehicles such as trucks and buses, but can also be applied to vehicles such as passenger cars.

[0014] A vehicle 10 to which the battery management device of this embodiment is applied is an electric vehicle (EV) or a hybrid vehicle. The EV 10 is equipped with a battery (not shown) for supplying power to a driving power source (motor). The battery gradually deteriorates according to the number of cycles, which is the number of times the battery is repeatedly charged and discharged. It is also known that the deterioration speed of the battery increases according to the usage conditions. In the following explanation, the power supply destination, such as a motor to which power is supplied from the battery, may be referred to as a "load".

[0015] The EV 10 is provided with a vehicle control unit 30 (Vehicle Control Unit: VCU). The VCU 30 judges the state of the EV 10 and executes control to maintain the EV 10 in an optimal state. Specifically, when the VCU 30 detects an abnormality in the EV 10, it controls the motor to stop the EV 10. The VCU 30 monitors the battery and acquires the operating time of the battery. The VCU 30 acquires the mileage of the EV 10. The VCU 30 also controls the power supplied from the battery to the load by changing the voltage between the battery and the load. The VCU 30 also controls a charger (not shown) so that the charging power when charging the battery does not exceed the chargeable power.

[0016] The battery operating time and the travel distance of the EV 10 are sent from the VCU 30 to the battery management device 20 .

[0017] The battery has a temperature sensor (not shown) and a voltage sensor (not shown). The temperature sensor detects the temperature of the battery and the temperature around the battery. The voltage sensor detects the voltage of the battery.

[0018] The EV 10 is provided with a monitoring unit 40 that monitors the usage status of the battery. The monitoring unit 40 acquires the detection results of each of the temperature sensor and the voltage sensor, and identifies the remaining capacity rate (State Of Health: SOH) based on the acquired detection results. The monitoring unit 40 also acquires the number of cycles of the battery. The number of cycles is a parameter that defines the number of charge / discharge cycles in which the battery is discharged from a charge amount equal to or greater than a first remaining amount to a charge amount equal to or less than a second remaining amount, and then charged again to a charge amount equal to or greater than the first remaining amount as 1. Note that the first remaining amount may be higher than the second remaining amount, and the first remaining amount may be fully charged. The monitoring unit 40 monitors the remaining amount of the battery, etc., and acquires the number of cycles the battery has gone through.

[0019] The monitoring unit 40 performs control for safe and effective use of the battery. Specifically, the monitoring unit 40 controls a relay (not shown) that connects / disconnects the battery and the load based on the detection results of the temperature sensor and the voltage sensor.

[0020] The detection results of the temperature sensor and the voltage sensor, the cycle number, and the SOH are sent from the monitoring unit 40 to the battery management device 20. The detection results of the temperature sensor and the voltage sensor, and the cycle number correspond to the "battery usage history" in this disclosure. The SOH corresponds to the "battery deterioration level" in this disclosure.

[0021] A battery management device 20 is provided for each vehicle 10. The battery management device 20 includes a control unit 21 and a memory unit 27. In FIG. 1, arrows indicate main data flows, and there may be data flows not shown in FIG. 1. In FIG. 1, each functional block indicates a configuration in function units, not a configuration in hardware (device) units. Therefore, the functional blocks shown in FIG. 1 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between functional blocks via any means, such as a data bus or a controller area network (CAN bus).

[0022] The management device 20 may be provided for a plurality of vehicles 10. As an example of this case, the management device 20 is provided in a server (not shown). Each of the vehicle 10 and the server has a communication unit, and the vehicle 10 and the server communicate with each other via a network.

[0023] The memory unit 27 is a storage device such as a ROM (Read Only Memory) that stores the BIOS (Basic Input System) of the computer that realizes the management device 20, a RAM (Random Access Memory) that serves as the working area of ​​the management device 20, an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores the OS (Operating System), application programs, and various information referenced when the application programs are executed.

[0024] The control unit 21 is a processor such as a CPU (Central Processing Unit) or GPU (Graphic Processing Unit) of the management device 20, and functions as an acquisition unit 22, a first calculation unit 23, a second calculation unit 24, a third calculation unit 25, a judgment unit 26, and an identification unit 28 by executing programs stored in the memory unit 27.

[0025] FIG. 1 shows an example in which the management device 20 is configured as a single device. However, the management device 20 may be realized by, for example, a plurality of processors, a memory, and other computing sources. In this case, each unit constituting the control unit 21 is realized by at least one of a plurality of different processors executing a program. In addition, when the management device 20 is configured as a single device, for example, the management device 20 may be configured as all of the VCU 30 and the monitoring unit 40 shown in FIG. 1. When the management device 20 is configured as a plurality of devices, for example, the management device 20 may be configured as each of the VCU 30 and the monitoring unit 40, or may be configured as a combination of any two devices and another device.

[0026] The acquiring unit 22 acquires the usage history of the battery (the detection results of the temperature sensor and the voltage sensor, and the number of cycles) from the monitoring unit 40. The acquiring unit 22 also acquires the SOH from the monitoring unit 40.

[0027] The storage unit 27 stores the battery usage history and SOH acquired by the acquisition unit 22. FIG. 2 is a diagram showing an example of accumulated data stored in the storage unit 27. As shown in FIG. 2, the storage unit 27 accumulates data on the SOH, operating time, mileage, and accumulated power amount for each date. Here, "operating time" refers to the operating time of the battery, "mileage" refers to the mileage of the EV 10, and "accumulated power amount" refers to the accumulated power consumption of the battery. It can be said that the storage unit 27 stores data on the SOH, operating time, mileage, and accumulated power amount in association with the timing at which each data was acquired.

[0028] The first calculation unit 23 calculates an approximation line representing the relationship between the usage history and the deterioration degree based on the usage history and the SOH. The "approximation line" is also called an approximation curve or a deterioration curve. A known method is used to calculate the approximation line. For example, the first calculation unit 23 calculates the approximation line by plotting the accumulated data accumulated in the storage unit 27 on a scatter diagram with the horizontal axis representing "date" and the vertical axis representing SOH. In the present disclosure, the accumulated data used to calculate the approximation line is not limited to "date". For example, it may be "mileage", "integrated power amount", or "number of cycles".

[0029] FIG. 3A is a diagram showing the relationship between seasons and temperatures. FIG. 3B is a scatter diagram and an approximation line in this embodiment. In FIG. 3B, the horizontal axis indicates "date" and the vertical axis indicates "SOH." As shown in FIG. 3B, the scatter diagram plots SOH corresponding to the date. Note that the scatter diagram plots multiple SOHs corresponding to multiple seasons, but FIG. 3B shows S31 and S32 as representatives of the multiple SOHs plotted.

[0030] FIG. 3A shows that the temperature drops from "summer" to "autumn," drops further from "autumn" to "winter," rises from "winter" to "spring," and rises further from "spring" to "summer." The temperature of the battery changes according to the seasonal temperature. The rate of deterioration of the battery also changes according to the battery temperature.

[0031] Fig. 4 is a diagram showing the relationship between the battery temperature and the battery degradation rate. In Fig. 4, the horizontal axis indicates the battery temperature, and the vertical axis indicates the battery degradation rate. Here, the battery degradation rate is expressed as the ratio of the state of health (SOH) to the number of cycles N (=SOH / N). As shown in Fig. 4, the battery degradation rate increases as the battery temperature increases.

[0032] The second calculation unit 24 calculates the average value of the battery temperature acquired during a predetermined period. Specifically, the second calculation unit 24 calculates the average value of the battery temperature in each of "spring", "summer", "autumn", and "winter". Note that the "predetermined period" is not limited to three months, which is the period of each of the multiple seasons, but may be 10 days, 20 days, one month, or two months. The third calculation unit 25 calculates the deterioration rate of the battery based on the average temperature of the battery and with reference to the diagram shown in FIG.

[0033] FIG. 5 is a diagram showing the relationship between the number of cycles and SOH for each temperature of the battery. The horizontal axis of FIG. 5 shows the number of cycles N, and the vertical axis shows SOH. In FIG. 5, the relationship between the number of cycles and SOH when the temperature of the battery is 20° C. is shown by a dotted line. Also, the relationship between the number of cycles and SOH when the temperature of the battery is 40° C. is shown by a dashed line. The inclination angle of the dashed line in FIG. 5 is steeper than the inclination angle of the dotted line. The inclination angle becomes steeper as the temperature of the battery increases. Also, the deterioration rate of the battery at each of the other temperatures of the battery can be expressed as an inclination angle, similar to the cases of 20° C. and 40° C. The deterioration rate of the battery can be expressed as an inclination angle of a straight line in this way. Note that the deterioration rate of the battery is shown in FIG. 5 by the relationship between the number of cycles and SOH, but may be shown by the relationship between the “date” and SOH. For example, if the average temperature for the three months of “spring” is 20° C., the deterioration degree of the battery in those three months can be expressed based on the inclination of the dotted line shown in FIG. 5. Also, for example, the battery deterioration rate (slope angle) for each of the three months of "summer," "autumn," and "winter" other than "spring" is calculated based on the average temperatures of "summer," "autumn," and "winter."

[0034] The first calculation unit 23 calculates, for example, approximation lines for each of "spring", "summer", "autumn" and "winter" based on the calculated deterioration rate (slope angle). The first calculation unit 23 also calculates a judgment reference line for the approximation line based on the temperature of the battery. FIG. 3B shows the approximation lines Lspr, Lsum, Laut, and Lwin for each of "spring", "summer", "autumn" and "winter". FIG. 3B also shows a judgment reference line Lrsum for the approximation line Lsum as a representative judgment reference line for each of the approximation lines Lspr, Lsum, Laut, and Lwin. FIG. 3B also shows an approximation line Ly calculated based on the deterioration rate (slope angle) in one year (12 months), and also shows a judgment reference line Lry for the approximation line Ly.

[0035] The determination unit 28 determines the estimated life of the battery based on the approximation lines Lspr, Lsum, Laut, and Lwin. The determination unit 28 determines the estimated life Da of the battery from the intersection of the approximation lines Lspr, Lsum, Laut, and Lwin with the life line Lb. The determination unit 28 determines the date on which the SOH reaches the life line Lb along the approximation lines Lspr, Lsum, Laut, and Lwin as the estimated life Da. The estimated life Db determined by the determination unit 28 is stored in the memory unit 27. In addition, the estimated life Db is transmitted to a management server that manages the EV 10 via a communication unit (not shown). The estimated life Db may be notified to a user of the EV 10 by displaying it on a display device of the EV 10.

[0036] Next, a scatter diagram and an approximation line according to a comparative example will be described with reference to Fig. 6. Fig. 6 shows a scatter diagram and an approximation line according to a comparative example. The horizontal axis in Fig. 6 indicates "date" and the vertical axis indicates "SOH". In Fig. 6, the plotted SOH is shown as S11, S12, S13, S14, S15, S16, S17, and S21.

[0037] In the comparative example, an approximation line La is calculated based on the plotted SOH S11, S12, S13, S14, S15, S16, and S17. In FIG. 6, the "approximation line La" is shown by a dotted line, and the "life line Lb (usage limit)" is shown by a dashed line. Furthermore, the SOH at which the life line Lb is reached is estimated based on the approximation line La. In FIG. 6, the estimated SOH is shown as S30. Furthermore, the date Da at which the SOH will reach the life line Lb is calculated based on S30. The date Da is shown in FIG. 6.

[0038] However, in the comparative example, the temperature of the battery is not taken into consideration when the approximation line La is created. In FIG. 6, the SOH that changes with the temperature of the battery with respect to the approximation line La is shown by S21. In FIG. 6, the approximation line La1 is calculated based on the plotted SOHs S11, S12, S13, S14, S15, and S21. In the comparative example, the SOH that will reach the life line Lb is estimated based on the approximation line La1. Also, the date Da1 when the SOH will reach the life line Lb is calculated based on the estimated SOH S31. The estimated SOH is shown by S31 in FIG. 6. Also, the date Da1 is shown in FIG. 6.

[0039] As described above, in the comparative example, the temperature of the battery is not taken into consideration when creating the approximation line La1. As a result, as shown in Fig. 6, the date when the life line Lb is reached is Da1, and the life of the battery is estimated to be significantly shorter than the date Da when the date when the life line Lb is reached is calculated based on the approximation line La.

[0040] In addition, in the comparative example, the judgment reference line is not calculated based on the temperature of the battery. For example, the judgment reference line in the comparative example is set to a constant value. As a result, as shown in FIG. 3B, when the SOH of the battery is estimated based on the judgment reference line Lry with respect to the approximation line Ly, the plotted SOH S32 is located below the judgment reference line Lry, and therefore may be erroneously judged as a rapid deterioration of the battery.

[0041] In contrast, in the present embodiment, the temperature of the battery is taken into consideration when the approximation line is created. Also, the judgment reference line is calculated based on the temperature of the battery. As a result, in the present embodiment, for example, as shown in FIG. 3B, when the SOH of the battery is estimated based on the judgment reference line Lrsum for the approximation line Lsum, the plotted SOH S32 is located above the judgment reference line Lrsum, and therefore the judgment unit 26 judges that the battery is in normal deterioration. This makes it possible to prevent erroneous judgment of the deterioration level of the battery.

[0042] The battery management device 20 in the above embodiment includes an acquisition unit 22 that acquires data on the battery usage history, the battery deterioration level, and the battery temperature, which is the temperature caused by battery deterioration, a first calculation unit 23 that calculates an approximation line representing the relationship between the usage history and the deterioration level according to the battery temperature based on the acquired data, and a determination unit 26 that determines whether the acquired deterioration level is within an acceptable range for the approximation line.

[0043] With the above configuration, even if the SOH plotted in the scatter diagram is located below the approximation line, if it is within the acceptable range, it is determined that the battery is experiencing normal deterioration, thereby making it possible to prevent erroneous determination of the degree of deterioration of the battery.

[0044] In addition, in the battery management device 20 in the above embodiment, the allowable range is set according to the battery temperature. This allows the allowable range to be set wider according to the battery temperature, making it possible to further prevent erroneous determination of the deterioration level of the battery.

[0045] In addition, in the battery management device 20 in the above embodiment, the allowable range is a judgment reference line for the approximation line, and the first calculation unit 23 calculates the judgment reference line based on the battery temperature. This makes it possible to adjust the judgment reference line according to the battery temperature, thereby making it possible to further prevent erroneous judgment of the deterioration level of the battery.

[0046] Moreover, the battery management device 20 in the above embodiment further includes a second calculation unit that calculates an average value of the battery temperature acquired during a predetermined period, and a third calculation unit that calculates the deterioration rate of the battery based on the calculated average value, and the first calculation unit 23 calculates an approximation line for the predetermined period based on the calculated deterioration rate. As a result, the approximation line is calculated based on each average value for the predetermined period (for example, summer), so that the deterioration degree of the battery can be determined in more detail.

[0047] In the above embodiment, the estimated lifespan is determined using an approximation line of the SOH versus date, but this is not limited to the above. The estimated lifespan may be determined using other usage histories, such as the detection results of a temperature sensor, the detection results of a voltage sensor, or an approximation line of the SOH versus the number of cycles.

[0048] In addition, the above-mentioned embodiments are merely examples of the embodiment of the present disclosure, and the technical scope of the present disclosure should not be interpreted as being limited by them. In other words, the present disclosure can be embodied in various forms without departing from the gist or main features thereof. [Industrial Applicability]

[0049] The present disclosure is preferably used in vehicles equipped with a battery management device that is required to prevent erroneous determination of the battery degradation level by taking the battery temperature into consideration. [Explanation of symbols]

[0050] La approximation line La1 approximation line Lb Life Line Lspr approximation line Lsum approximation line Laut approximation line Lwin approximation line Ly approximation line Lrsum Criterion Line Lry judgment reference line 10 Electric Vehicles (EV) 20 Battery management device 21 Control section 22 Acquisition Department 23 First calculation section 24 Second Calculation Section 25 Third calculation section 26 Judgment section 27 Memory section 30 VCU 40 Monitoring Department

Claims

1. an acquisition unit that acquires data on a battery usage history, a deterioration level of the battery, and a temperature of the battery, which is a temperature caused by deterioration of the battery; a first calculation unit that calculates an approximation line representing a relationship between the usage history and the deterioration degree according to a temperature of the battery based on the acquired data; a second calculation unit that calculates an average value of the temperature of the battery acquired during a predetermined period; a third calculation unit that calculates a deterioration rate of the battery based on the calculated average value; a determination unit that determines whether the acquired deterioration degree is within an allowable range with respect to the approximation line; Equipped with The first calculation unit calculates the approximation line for the predetermined period based on the calculated deterioration rate, The first calculation unit further calculates a determination reference line for the approximation line based on a temperature of the battery; the determination unit determines whether the acquired deterioration degree is within an allowable range with respect to the approximation line based on the determination reference line. Battery management device.

2. The judgment reference line is adjustable according to the temperature of the battery. The battery management device according to claim 1 .

3. The usage history of the battery includes at least one of the number of cycles of the battery, the usage time, the temperature of the battery, and the voltage of the battery. The battery management device according to claim 1 .

4. The deterioration level of the battery includes a remaining capacity rate of the battery. The battery management device according to claim 1 .

5. Obtaining data on a battery usage history, a battery deterioration level, and a battery temperature, which is a temperature caused by battery deterioration; calculating an approximation line representing a relationship between the usage history and the deterioration degree according to the temperature of the battery based on the acquired data; Calculating an average value of the temperature of the battery acquired during a predetermined period; Calculating a deterioration rate of the battery based on the calculated average value; calculating the approximation line for the predetermined period based on the calculated deterioration rate; calculating a judgment reference line for the approximation line based on a temperature of the battery; determining whether the acquired deterioration degree is within an allowable range with respect to the approximation line based on the determination reference line; How to manage the battery.

6. The judgment reference line is adjustable according to the temperature of the battery. The battery management method according to claim 5 .

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