Battery management device, battery management method, and battery management program

Abstract

To provide a technology that can accurately estimate the degree of battery wear in a short time.SOLUTION: A battery management device according to the present invention estimates a deterioration mode of a battery based on a change in battery voltage over time during a rest period of the battery, selects the Eyring plot corresponding to the estimated deterioration mode, and diagnoses the state of the battery based on the selected plot.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a technology for managing the state of a battery. [Background technology]

[0002] The rate at which secondary batteries deteriorate varies depending on the ambient environment during operation, the C rate, the charging and discharging method, etc. However, common battery diagnostic methods diagnose the state of health (SOH) using only the current state of the battery, which can result in significant errors in the prediction results.

[0003] The following Patent Document 1 addresses the issue of "providing a storage battery management system, a storage battery information server, a charge / discharge control device, and a storage battery that aim to predict the lifespan of a secondary battery as accurately as possible and properly use up the secondary battery while preventing accidents," and describes the following technology (see abstract): "A unique LIBID is assigned to each LIB, and the operating status of the LIB is recorded in a log table, which is then aggregated in a LIB usage log table by the LIB information server. The cumulative failure probability is then calculated based on the huge LIB usage log table, and a cumulative failure probability table is created. The charge / discharge control device calculates the optimal replacement time for the LIB based on the cumulative failure probability table, storage time gradient function, loss cost function, replacement cost function, warning threshold, and usage prohibition threshold received from the LIB information server via the LIB."

[0004] The following Patent Document 2 addresses the issue of "providing a calculation method, calculation program, calculation system, and calculation device for calculating the internal state of a secondary battery with high accuracy," and describes a technology in which "a calculation method is implemented in which a calculation device 10 equipped with a calculation processing unit 100 that calculates the internal state of a secondary battery BT reads the voltage and current of the secondary battery BT from a storage unit 160, calculates three or more characteristic parameters that are not dependent on each other and are included in a characteristic formula P of the secondary battery BT, the three or more characteristic parameters including a constant term near a charge / discharge intermediate value, an exponent term near a limit value, and a charge / discharge limit value, calculates the internal state of the secondary battery using the calculated characteristic parameters, and stores the calculated internal state in the storage unit 160" (see abstract). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-034781 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-167568 Summary of the Invention [Problem to be solved by the invention]

[0006] When estimating the remaining life of a battery, it is useful to estimate the degree of wear of the battery. In conventional battery diagnosis such as those described in Patent Documents 1 and 2, a battery with a large decrease in SOH is generally judged to be in a worn state as a relative evaluation. However, there are various causes of SOH decrease, and a battery with a low SOH is not necessarily in a worn state. It is also desirable to shorten the time required to diagnose the remaining life as much as possible.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to provide a technique that can accurately estimate the degree of wear of a battery in a short period of time. [Means for solving the problem]

[0008] The battery management device according to the present invention estimates the deterioration mode of a battery based on the change over time in battery voltage during a rest period of the battery, selects the Eyring plot corresponding to the estimated deterioration mode, and diagnoses the state of the battery based on the selected plot. [Effects of the Invention]

[0009] The battery management device according to the present invention can accurately estimate the degree of wear of a battery in a short time. Other objects, configurations, effects, etc. of the present invention will become clear from the following description of the embodiment. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration example of a battery storage system. [Figure 2] 1 shows the change in battery voltage over time during a rest period after a charging or discharging operation. [Figure 3] 10 is a graph showing the relationship between ΔVa and ΔVb. [Figure 4] FIG. 10 is a schematic diagram showing an example of selecting an Eyring plot corresponding to a battery degradation mode. [Figure 5] 10 is a flowchart illustrating a procedure for estimating a deterioration rate. [Figure 6] FIG. 1 is a schematic diagram showing a procedure for determining the degree of wear of a battery using the battery state and an Eyring plot. [Figure 7] FIG. 10 is a diagram illustrating a procedure for determining the current cycle number of a battery. [Figure 8] 4 is a flowchart illustrating the operation of the battery management device according to the first embodiment. [Figure 9] 10 is a flowchart illustrating another operation of the battery management device. [Figure 10] This shows the change in battery state due to the adoption of an operating method that suppresses the progression of battery deterioration. [Figure 11] 10 is an example of a data table describing the results of a battery diagnosis performed by a battery management device. [Figure 12]FIG. 1 is a configuration diagram of a battery system 1. [Figure 13A] 10 is an example of a user interface provided by the battery management device. [Figure 13B] 10 is an example of a user interface provided by the battery management device. [Figure 14] FIG. 10 is a diagram illustrating an example of the results of plotting the current states of multiple batteries on an Eyring plot. [Figure 15] FIG. 1 is a schematic diagram showing a procedure for creating an Eyring plot for the entire battery system. [Figure 16] 10 is a histogram showing the results of counting the degree of deviation between the threshold and the Eyring plot for each individual battery. [Figure 17] 10 is a flowchart illustrating the operation of the battery management device according to the second embodiment. [Figure 18] FIG. 10 is a diagram illustrating an example of operation of the battery management device 13. [Figure 19] FIG. 10 is a diagram showing another example of operation of the battery management device 13. [Figure 20] 20 is a flowchart illustrating a process performed by a battery management unit 13 in the system configuration of FIG. 19. DETAILED DESCRIPTION OF THE INVENTION

[0011] <First Embodiment> Figure 1 is a schematic diagram showing an example of the configuration of a storage battery system. The storage battery system is composed of a battery system made up of one or more storage batteries and a battery management device that manages the battery system. In the following, the battery is assumed to be a storage battery.

[0012] The battery system includes a battery module. The battery module is composed of one or more sub-modules. The sub-module has a battery cell and a group of sensors. The group of sensors may include, for example, a voltage sensor that measures the output voltage of the battery cell, a temperature sensor that measures the temperature of the battery cell, and a current sensor that measures the output current of the battery cell. The temperature sensor may be composed of, for example, a thermocouple. The detection unit acquires the measurement results from the sensor and transmits them to a battery management module (BMU). The BMU outputs measurement data describing the measurement results to the battery management unit.

[0013] The battery management device includes a detector that acquires measurement data, a calculator that manages the battery status, and a memory that stores the data. The calculator estimates the battery status using the measurement data acquired from the BMU. For example, as described below, it can estimate the remaining battery life (or the degree of wear used to estimate the remaining battery life).

[0014] Figure 2 shows the change in battery voltage over time during a rest period after a charge or discharge operation. While the battery voltage after a discharge operation is shown here as an example, a similar change over time can also be observed after a charge operation. The battery voltage during the rest period has a voltage change ΔVa during a relatively early first period (time length Δt1) and a voltage change ΔVb during a relatively late second period (time length Δt2). ΔVa is a response component due to components with a small time constant in the battery's equivalent circuit, such as the internal resistance or the negative electrode. ΔVb is a response component due to components with a large time constant in the battery's equivalent circuit, such as the positive electrode or diffusion resistance.

[0015] As a result of investigations by the inventors, it was found that the ratio between ΔVa and ΔVb corresponds to the deterioration mode (deterioration rate) of the battery. Therefore, in the present invention, the deterioration mode is estimated using ΔVa and ΔVb (or the time change rate of these) according to the procedure described below, and the wear state of the battery is further estimated using the Eyring plot corresponding to that deterioration mode.

[0016] FIG. 3 is a graph showing the relationship between ΔVa and ΔVb. For batteries with a low degradation rate, when ΔVa and ΔVb are plotted as in FIG. 3, the plots are concentrated near a certain threshold. In contrast, the inventors have found through their investigation that for batteries with a high degradation rate, these plots exist in a region above the threshold. Therefore, in the present invention, it is possible to estimate whether the battery has deteriorated in a mode with a high or low degradation rate based on whether these plots are above the threshold.

[0017] The plots of ΔVa and ΔVb may be either the upper or lower part of FIG. 3. That is, the horizontal axis may be ΔVb / Δt2, and the vertical axis may be either (ΔVa / Δt1) / (ΔVb / Δt2) or ΔVa / Δt1. In either plot, the plots of batteries with a high rate of deterioration are plotted in the region exceeding the threshold on the vertical axis, as indicated by the black circles in FIG. 3. That is, batteries with plots exceeding the threshold on the vertical axis in FIG. 3 can be determined to have a high rate of deterioration.

[0018] FIG. 4 is a schematic diagram showing an example of selecting an Eyring plot corresponding to a battery degradation mode. The memory unit of the battery management device stores data describing an Eyring plot for each battery degradation mode (degradation rate). The calculation unit estimates the battery degradation rate and selects from the data an Eyring plot corresponding to that degradation rate. The calculation unit uses the Eyring plot to estimate the degree of wear of the battery according to the procedure described below.

[0019] The Eyring plot to be stored in the storage unit is created in advance. The slope of the Eyring plot can be determined based on, for example, the activation energy of the battery. The intercept of the Eyring plot can be determined based on, for example, the SOH of the battery. Furthermore, since the Eyring plot may differ depending on whether the plot in the upper or lower part of Figure 3 is used, Eyring plots corresponding to the vertical axes of Figure 3 may be prepared in advance.

[0020] FIG. 5 is a flowchart explaining the procedure for estimating the deterioration rate. The calculation unit of the battery management device acquires data describing the measurement results of ΔVa and ΔVb, for example, from the BMU. The calculation unit plots these as shown in FIG. 3. If the plot exceeds a threshold, the deterioration rate of the battery is estimated to be A (relatively high), and if it is below the threshold, the deterioration rate is estimated to be B (relatively low). Furthermore, the plot may be compared with a lower threshold. In this case, the deterioration rate is estimated to be A to C (relatively the lowest).

[0021] Figure 6 is a schematic diagram showing the procedure for determining the degree of battery wear using the battery state and the Eyring plot. Based on the battery measurement results, plots corresponding to the vertical and horizontal axes of the Eyring plot are obtained. The degree of battery wear is estimated by comparing the plot with the Eyring plot selected in Figure 5.

[0022] If the plot obtained from the battery measurement results is on the Eyring plot (or within the predetermined shaded range near the Eyring plot) (Fig. 6(i)), the battery is presumed to be not in a worn state (normal). If the plot obtained from the battery measurement results is outside the predetermined range (Fig. 6(ii)), the battery is presumed to be not in a worn state, but to be deteriorating if the current operating conditions are continued. In this case, the operating conditions of the battery may be readjusted, as described below. If the plot obtained from the battery measurement results is further outside the predetermined range (Fig. 6(iii)), the battery is presumed to be in a worn state.

[0023] Since the intercept of the Eyring plot corresponds to the SOH, the upper and lower limits of the range in which a battery is considered normal on the Eyring plot can also be determined based on the upper and lower limits of the SOH. However, when a battery with a significantly reduced SOH is plotted on the Eyring plot, it may fall within this normal range. This is thought to be due to a reduction in SOH caused by factors other than wear. In other words, the inventors' investigations have revealed that determining whether a battery is in a worn state using only the SOH may not be appropriate. Therefore, in the present invention, whether a battery is in a worn state is determined based on the degree of deviation from the normal range on the Eyring plot.

[0024] For example, if the distance from the normal range (shaded range) in the two-dimensional coordinate space of Figure 6 to the plotted point is equal to or greater than a first threshold, the battery is determined to be in the state shown in Figure 6(iii) (worn state). If the distance from the normal range to the plotted point is less than the first threshold and equal to or greater than a second threshold (second threshold≦distance<first threshold), the battery is determined to be in the state shown in Figure 6(ii) (a state in which deterioration will progress if the battery is used as is).

[0025] 7 is a diagram illustrating the procedure for calculating the current cycle number of a battery. When creating an Eyring plot or plotting actual battery measurement results on the created Eyring plot, it is necessary to calculate the number of charge / discharge cycles the battery has undergone so far (current cycle number). Therefore, in the present invention, the current cycle number is calculated using the following procedure.

[0026] The SOH of a battery is defined, for example, by the amount of discharge current when the battery is fully discharged from a full charge. In this case, the SOH can be defined by the absolute value of the amount of discharge current. The relationship between the amount of discharge current and the number of cycles is as shown in the bottom of Figure 7. In other words, for a normal battery, the amount of discharge current is unlikely to decrease even with the number of cycles, whereas for a deteriorated battery, the amount of discharge current decreases as the number of cycles increases.

[0027] The relationship in the lower part of Figure 7 shows that the greater the drop in discharge current, the more advanced the deterioration. Therefore, the current cycle number can be expressed as a function proportional to the inverse of the drop in discharge current from the normal state (capacity fade). That is, the following equation holds: current cycle number = a / capacity fade + b. The value on the vertical axis when plotting the current state of the battery on an Eyring plot (i.e., the value on the vertical axis of the white circle in Figure 7) can be calculated using this equation.

[0028] FIG. 8 is a flowchart illustrating the operation of the battery management device in the first embodiment. This flowchart can be implemented by a calculation unit provided in the battery management device. This flowchart determines the degree of wear of the battery based on the principle explained above. Each step in FIG. 8 will be explained below.

[0029] The calculation unit acquires ΔVa and ΔVb described in Fig. 2 from, for example, the BMU. The calculation unit further acquires the battery state of charge (SOC), battery temperature, battery current, etc. from, for example, a measuring device. The sources from which this measurement data is acquired are not limited to the above.

[0030] The calculation unit estimates the deterioration rate of the battery using the method described in Figures 3 to 5 and selects an Eyring plot corresponding to the estimated deterioration rate. Data describing the Eyring plot is stored in advance in a memory unit provided in the battery management device. More specifically, since the slope of the Eyring plot corresponds to the deterioration mode, the deterioration mode is estimated using the method described in Figures 3 to 5 and the slope corresponding to that deterioration mode is identified.

[0031] The calculation unit acquires the results of measuring or estimating the battery's SOH. The SOH can be estimated, for example, by referencing data describing the correspondence between ΔVa and ΔVb, their time change rates, and the SOH, as described in Figure 2. Alternatively, the SOH measurement results may be acquired from an external device such as a BMU. The SOH corresponds to the intercept of the Eyring plot. By identifying the slope and intercept of the Eyring plot, the calculation unit can select the Eyring plot corresponding to the degradation mode.

[0032] The calculation unit plots the current battery state on the selected Eyring plot. Specifically, the difference between the current battery temperature and the standard temperature is defined as ΔT, and the current cycle number calculated using the method described in Figure 7 is defined as N, and these are plotted on the Eyring plot. The calculation unit further estimates the degree of battery wear based on the distance between the Eyring plot and the plot of the current battery state, using the method described in Figure 6.

[0033] FIG. 9 is a flowchart illustrating another operation of the battery management device. In addition to the flowchart of FIG. 8, the calculation unit may also determine whether to use an operating method (degradation mitigation operation mode) that suppresses the progression of battery degradation. For example, if the degree of battery wear corresponds to the middle row of FIG. 6, it is considered possible to suppress further degradation by using an operating method that suppresses the progression of degradation. If the degree of wear is in the upper row of FIG. 6, normal operation can be continued. If the degree of wear is in the lower row of FIG. 6, it is possible to output an alert, for example, to encourage replacement.

[0034] Examples of operational methods for suppressing the progression of battery deterioration include setting at least one of the following restrictions: setting at least one of an upper or lower limit for battery voltage; setting an allowable range for battery temperature; and setting at least one of an upper or lower limit for SOC.

[0035] Figure 10 shows how the battery state changes when an operating method that suppresses the progression of battery degradation is adopted. When the current battery state deviates from the Eyring plot (top of Figure 10), adopting an operating method that suppresses the progression of battery degradation will bring the battery state onto the Eyring plot (or within a specified range near the Eyring plot). This suppresses further progression of battery degradation and extends the remaining lifespan.

[0036] Fig. 11 is an example of a data table that describes the results of the battery diagnosis performed by the battery management unit. For each battery to be diagnosed, the battery management unit may record measurement data acquired from the BMU or the like, the degree of wear determined according to the flowchart in Fig. 9 (whether or not to change the operating method), and so on in a data table, and store the data in a memory unit.

[0037] FIG. 12 is a configuration diagram of a battery system 1. The battery system 1, battery controller (BMU) 12, and battery management unit 13 are the same as those shown in FIG. 1. The battery system 1 has a host controller 11, battery controller (BMU) 12, and battery management unit 13. The host controller 11 outputs operation instructions to the battery via the battery controller 12. The battery controller 12 controls the battery modules in accordance with the instructions. The battery management unit 13 has a detection unit 131 that acquires measurement data from the battery controller 12, a calculation unit 132 that diagnoses the battery using the method described above, and a memory unit 133 that stores data used by the calculation unit 132.

[0038] 13A and 13B are examples of a user interface provided by the battery management device. The user interface can display measurement data acquired in the process of implementing the flowchart of FIG. 9. For example, the change over time in battery voltage described in FIG. 3, the threshold value for determining the deterioration rate described in FIG. 4, etc. may be displayed. A Weibull distribution, which will be described later, may also be displayed.

[0039] <Embodiment 2> When a battery system is composed of multiple batteries, the degree of wear of the entire battery system may be determined. In this case, as in the first embodiment, the current state of each battery can be plotted on an Eyring plot to determine the degree of wear of the entire battery system. Therefore, in a second embodiment of the present invention, an example of the operation of a battery management device that diagnoses the state of the entire battery system will be described. The configurations of the battery system and the battery management device are the same as those of the first embodiment.

[0040] Figure 14 is a diagram illustrating the results of plotting the current states of multiple batteries on an Eyring plot. For example, if there are relatively few batteries that deviate from the Eyring plot, as in the middle of Figure 14, an operating method that suppresses the progression of deterioration can be adopted. However, if there are many batteries that deviate significantly from the Eyring plot, as in the bottom of Figure 14, it can be considered that the entire battery system is in a worn state. Below, we will explain an example of using a Weibull plot as a procedure for diagnosing the state of the entire battery system.

[0041] Figure 15 is a schematic diagram showing the procedure for creating an Eyring plot for the entire battery system. Although an Eyring plot can be created for each battery, since a battery system is composed of multiple batteries, the following procedure is used to create a single Eyring plot for the entire battery system.

[0042] The calculation unit acquires measurement data of the battery voltage of each battery from, for example, the BMU, and selects an Eyring plot for each battery using the method described in embodiment 1. The calculation unit selects an Eyring plot for the entire battery system by identifying, from among the Eyring plots, one in which all batteries included in the battery system fall within the normal range of the Eyring plot. This Eyring plot is used as a reference when determining the degree of wear of the entire battery system.

[0043] FIG. 16 is a histogram showing the results of counting the deviation between the threshold and the Eyring plot for each individual battery. By calculating the deviation between the Eyring plot for the entire battery system and the threshold, it is possible to grasp the variation in the degree of battery wear and outliers. The calculation unit uses the batteries shown in this histogram whose degree of wear deviates from the Eyring plot for the entire system to create a Weibull plot, as described below.

[0044] By using statistical values ​​such as those shown in Figure 16, it is possible to statistically calculate outlier batteries in a battery system that deviate significantly from the threshold. In particular, even for batteries that have a low SoH calculated using the amount of discharge current and appear to be worn out at first glance, the Eyring plot can be used to determine whether the battery is still usable in the overall battery system. Conversely, even if a battery has a high SoH calculated using the amount of discharge current and appears healthy at first glance, if it deviates from the normal range of the Eyring plot, it can be detected as a sign of wear.

[0045] 17 is a flowchart illustrating the operation of the battery management device according to the second embodiment. As in the first embodiment, the calculation unit plots the measurement results of the current battery on an Eyring plot. When this flowchart is implemented for a battery system, this Eyring plot is a single Eyring plot selected for the entire battery system, as described in FIG.

[0046] When the measurement results of each battery are plotted on an Eyring plot, the calculation unit identifies plots that deviate from the normal range (i.e., those corresponding to the rightmost column in Figure 16). The calculation unit creates a Weibull plot using the measurement results of the deviating battery. For example, the horizontal axis represents the logarithm of the elapsed time since the start of operation, and the vertical axis represents the logarithm of the cumulative failure rate. Whether or not a battery has reached a failure state can be determined from the SOH value. A Weibull plot can be obtained by plotting the measurement results of a battery that deviates from the normal range on both axes. Since a Weibull plot has time-dependent elements, namely, the elapsed time and the cumulative failure rate, it should be noted that the battery measurement data acquired by the calculation unit in this flowchart is a time-dependent history.

[0047] The calculation unit calculates the shape parameter m of the created Weibull plot. For example, the shape parameter m can be obtained by determining the slope of the regression line of the plot of the deviating battery. If the shape parameter m of the Weibull distribution exceeds 1, the calculation unit estimates that the battery system is in a worn state. If m is 1 or less, it determines that the battery system is operating within the appropriate operating range.

[0048] According to the second embodiment, even if the SOH of the entire battery system is deteriorated, it can be statistically determined that there is no problem with the entire battery system as long as the stress is moderate. If it is estimated that the entire battery system is worn out, measures can be taken such as changing the operating conditions of the battery system or replacing batteries that are significantly worn out, as in Fig. 9.

[0049] <Third Embodiment> 18 is a diagram showing an example of operation of the battery management device 13. The detection unit 131 acquires measured values ​​or their history, such as the battery voltage, battery temperature, battery current, C rate, and SOC, of ​​each battery module (or battery cell) from the BMU, and records them in the storage unit 133. The calculation unit 132 uses the data to estimate the degree of wear of the battery by the method described in the first embodiment, and can change the operation method as necessary (adopt an operation method that can suppress deterioration). This makes it possible to suppress the progression of battery deterioration.

[0050] For example, when transmitting power generated by a power generation system including a battery system over a power company's power transmission network, it is conceivable to create a power transmission plan in advance the day before the power transmission and send it to the power company, and then diagnose the degree of battery wear within a short time just before the start of power transmission on the day of the power transmission. In such cases, the diagnostic method according to the present invention is useful in that it can complete the diagnosis in a short time.

[0051] FIG. 19 is a diagram showing another example of operation of the battery management device 13. The battery management device 13 is connected to a charger via a cloud system or the like. The charger is a device that charges a battery mounted on a vehicle. The detection unit 131 acquires measurement data such as the battery voltage and battery temperature of the battery mounted on the vehicle via the charger (or via a measuring instrument connected to the vehicle). The calculation unit 132 can use the measurement data to diagnose the degree of wear of the battery using the method described in the first embodiment.

[0052] FIG. 20 is a flowchart illustrating the processing performed by the battery management device 13 in the system configuration of FIG. 19. This flowchart can be performed by the calculation unit 132. The detection unit 131 acquires battery measurement data from a BMU or the like. The calculation unit 132 plots the measurement results of each battery on an Eyring plot using the method described in the first embodiment. The calculation unit 132 creates a Weibull plot using the procedure described in the second embodiment. The calculation unit 132 estimates the degree of battery wear based on the shape parameter m of the Weibull plot. For batteries that have not yet reached a worn state but will continue to deteriorate if used as is (middle row in FIG. 6 and middle row in FIG. 14), the operation method is changed to one that suppresses the progression of deterioration. For batteries that have reached a worn state (lower row in FIG. 6 and lower row in FIG. 14), the time until they become unusable may be further estimated.

[0053] <Modifications of the present invention> The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0054] In the above embodiment, the start point of ΔVb is later than the start point of ΔVa, and the end point of ΔVb is later than the end point of ΔVa. As long as this relationship is maintained, for example, Δt1 (first period) and Δt2 (second period) may partially overlap.

[0055] In the above embodiments, the detection unit 131 and the calculation unit 132 can be configured by hardware such as a circuit device that implements their functions, or can be configured by a calculation device such as a CPU (Central Processing Unit) executing software that implements their functions. [Explanation of symbols]

[0056] 13:Battery management device 131: Detection unit 132: Arithmetic section 133: Storage section

Claims

1. A battery management device for managing the state of a battery, a detection unit that acquires a detected value of the voltage output by the battery; a storage unit for storing data describing an Eyring plot of the battery for each degradation mode of the battery; a calculation unit that estimates the state of the battery; Equipped with the calculation unit estimates a deterioration mode of the battery based on a change in the voltage over time during a rest period after the battery has finished charging or discharging; the calculation unit selects the Eyring plot corresponding to the estimated deterioration mode as a selected Eyring plot; The calculation unit diagnoses the state of the battery based on the selected Eyring plot. A battery management device characterized by:

2. The calculation unit diagnoses the state of the battery based on the degree of deviation between the selected Eyring plot and a plot point when the measurement value of the battery is plotted in the same coordinate space as the Eyring plot.

2. The battery management device according to claim 1.

3. the calculation unit calculates a distance in the coordinate space between the selected Eyring plot and the measurement value as the degree of deviation; The calculation unit diagnoses that the battery is worn out when the deviation is equal to or greater than a first threshold value.

3. The battery management device according to claim 2.

4. When the deviation is less than the first threshold value and equal to or greater than a second threshold value, the calculation unit controls the battery to operate in a degradation mitigation operation mode that mitigates the progression of degradation of the battery.

4. The battery management device according to claim 3.

5. The degradation mitigation operation mode includes: setting an upper or lower threshold for the voltage; limiting the temperature range in which the battery is operated so that the rate of deterioration of the battery is slower than before the deterioration mitigation operation mode was started; setting an upper or lower threshold for the state of charge of the battery; At least one of the following is true:

5. The battery management device according to claim 4.

6. The degradation mitigation operation mode is configured to extend the remaining life of the battery by changing the operating state of the battery so that the deviation is less than the second threshold value.

5. The battery management device according to claim 4.

7. the calculation unit acquires, as a capacity fade amount, an amount of decrease in capacity of the battery due to one charge or discharge operation of the battery; the calculation unit calculates the number of charge or discharge cycles performed by the battery according to a function proportional to the reciprocal of the capacity fade amount; The calculation unit plots the number of cycles as the measurement value on the coordinate space.

3. The battery management device according to claim 2.

8. the calculation unit selects a single Eyring plot for a battery system configured with a plurality of the batteries, the calculation unit identifies, among the batteries constituting the battery system, a battery whose deviation from the single Eyring plot is equal to or greater than a threshold value as a deviating battery; the calculation unit obtains a Weibull plot of the cumulative failure rate of the deviation battery and the operating time of the deviation battery; The calculation unit diagnoses a state of the battery system based on a shape parameter of the Weibull plot.

2. The battery management device according to claim 1.

9. The battery is mounted in a power interchange system that interchanges power between power transmission and distribution networks, the power interchange system includes a history storage unit that stores data describing a history of the voltage and a history of the state of charge of the battery; the calculation unit acquires the history of the voltage and the history of the state of charge from the history storage unit; The calculation unit diagnoses the state of the battery using the acquired history and controls the operating conditions of the battery according to the result of the diagnosis.

2. The battery management device according to claim 1.

10. The battery is mounted on an electric device that operates using the output from the battery as power, and the calculation unit acquires the change in voltage from the electric device or a measuring instrument connected to the electric device.

2. The battery management device according to claim 1.

11. the battery is mounted on an electric device that operates using an output from the battery as power, and the calculation unit acquires the change in voltage from the electric device or a measuring instrument connected to the electric device; The calculation unit controls the operating conditions of the battery in accordance with the shape parameters.

9. The battery management device according to claim 8.

12. the calculation unit determines a slope of the Eyring plot based on an activation energy of the battery; The calculation unit selects the Eyring plot for which the slope has been determined as the selected Eyring plot.

2. The battery management device according to claim 1.

13. the calculation unit determines an intercept of the Eyring plot based on a state of health of the battery; The calculation unit selects the Eyring plot for which the intercept has been determined as the selected Eyring plot.

2. The battery management device according to claim 1.

14. A battery management method for managing a battery state, comprising: obtaining a detected value of the voltage output from the battery; a step of estimating the state of the battery using data describing an Eyring plot of the battery for each degradation mode of the battery; and In the step of estimating, a deterioration mode of the battery is estimated based on a change in the voltage over time during a rest period after the battery has finished a charging operation or a discharging operation; In the step of estimating, the Eyring plot corresponding to the estimated deterioration mode is selected as a selected Eyring plot; In the step of estimating, the state of the battery is diagnosed based on the selected Eyring plot. A battery management method characterized by:

15. A battery management program that causes a computer to execute a process for managing a battery state, the program comprising: obtaining a detected value of the voltage output from the battery; a step of estimating the state of the battery using data describing an Eyring plot of the battery for each degradation mode of the battery; Execute In the estimating step, the computer is caused to execute a step of estimating a deterioration mode of the battery based on a change in the voltage over time during a rest period after the battery has finished a charging operation or a discharging operation; In the step of estimating, the computer is caused to execute a step of selecting the Eyring plot corresponding to the estimated deterioration mode as a selected Eyring plot; In the step of estimating, the computer is caused to execute a step of diagnosing the state of the battery based on the selected Eyring plot. A battery management program characterized by:

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