WO2024053143A1

WO2024053143A1 - Battery management device, battery management method, and battery management program

Info

Publication number: WO2024053143A1
Application number: PCT/JP2023/012808
Authority: WO
Inventors: 隼角田; 亨河野; 穣植田; 博也藤本; アキラ藤本; 絵里磯崎; 慧土秋月
Original assignee: 株式会社日立ハイテク
Priority date: 2022-09-05
Filing date: 2023-03-29
Publication date: 2024-03-14
Also published as: JP2024035923A

Abstract

The purpose of the present invention is to provide technology that enables a degree of wear of a battery to be accurately estimated in a short time. A battery management device according to the present invention estimates, on the basis of temporal change of battery voltage in a rest period of the battery, a deterioration mode of the battery, selects the Eyring plot corresponding to the deterioration mode that is estimated, and diagnoses a state of the battery on the basis of the plot that is selected (see Fig. 8).

Description

Battery management device, battery management method, battery management program

The present invention relates to a technology for managing the state of a battery.

The degree of deterioration of secondary batteries varies depending on the surrounding environment during operation, C rate, charging/discharging operation method, etc. However, since the general battery diagnosis method diagnoses the state of health (SOH) using only the current state of the battery, there is a possibility that a non-negligible error may occur in the prediction result.

Patent Document 1 below describes ``a storage battery management system, a storage battery information server, and a charging/discharging control device that aim to use up the secondary battery correctly while preventing accidents by predicting the lifespan of the secondary battery as accurately as possible. and storage batteries. The goal was to ``give a unique LIB ID to the LIB, record the operating status of the LIB in a log table, and aggregate it into a LIB usage log table on the LIB information server.'' Then, the cumulative failure probability is calculated based on the huge LIB usage log table, and a cumulative failure probability table is created. The charge/discharge control device determines the LIB based on the cumulative failure probability table, storage time gradient function, loss cost function, replacement cost function, warning threshold, and use prohibition threshold received from the LIB information server via LIB. Calculate the optimal replacement time. ” (see summary).

Patent Document 2 below provides a calculation method, a calculation program, a calculation system, and a calculation device that calculate the internal state of a secondary battery with high precision. 'The voltage and current of the secondary battery BT are read out from the storage unit 160 into the arithmetic unit 10 equipped with the arithmetic processing unit 100 that calculates the internal state of the secondary battery BT, and the characteristics of the secondary battery BT are calculated. Three or more characteristic parameters that are not dependent on each other and include a constant term near the charge/discharge intermediate value, a power term near the limit value, and the charge/discharge limit value included in the formula P are calculated. A calculation method for calculating an internal state of the secondary battery using the characteristic parameters and storing the calculated internal state in a storage unit 160. ” (see summary).

Japanese Patent Application Publication No. 2017-034781 Japanese Patent Application Publication No. 2013-167568

When estimating the remaining life of a battery, it is useful to estimate the degree of battery wear. In conventional battery diagnosis such as those disclosed in

Patent Documents

1 and 2, it is common to determine that a battery with a large decrease in SOH is in a worn state as a relative evaluation. However, there are various reasons why the SOH decreases, and a battery with a low SOH does not necessarily mean that it is in a worn out state. Furthermore, it is desirable to shorten the time required to diagnose the remaining life as much as possible.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a technique that can accurately estimate the degree of battery wear in a short time.

The battery management device according to the present invention estimates a deterioration mode of the 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 selects the Eyring plot corresponding to the estimated deterioration mode. The condition of the battery is diagnosed based on the plot.

According to the battery management device according to the present invention, the degree of battery wear can be accurately estimated in a short time. Other problems, configurations, effects, etc. of the present invention will become clear from the description of the embodiments below.

FIG. 1 is a schematic diagram showing a configuration example of a storage battery system. 3 shows a change in battery voltage over time during a rest period after a charging or discharging operation. It is a graph showing the relationship between ΔVa and ΔVb. FIG. 3 is a schematic diagram showing an example of selecting an Eyring plot corresponding to a battery deterioration mode. It is a flowchart explaining the procedure of estimating a deterioration rate. FIG. 2 is a schematic diagram showing a procedure for determining the degree of wear of a battery using the battery condition and an Eyring plot. It is a figure explaining the procedure of calculating|requiring the current cycle number of a battery. 7 is a flowchart illustrating the operation of the battery management device in the first embodiment. It is a flowchart explaining another operation of a battery management device. This figure shows changes in battery condition caused by adopting an operation method that suppresses the progress of battery deterioration. This is an example of a data table that describes the results of battery diagnosis performed by the battery management device. 1 is a configuration diagram of a battery system 1. FIG. It is an example of the user interface provided by the battery management device. It is an example of the user interface provided by the battery management device. FIG. 3 is a diagram illustrating the results of plotting the current states of a plurality of batteries on an Eyring plot. FIG. 3 is a schematic diagram showing a procedure for creating an Eyring plot for the entire battery system. This is a histogram showing the results of counting the degree of deviation between the threshold value and the Eyring plot for each individual battery. 7 is a flowchart illustrating the operation of the battery management device according to the second embodiment. 3 is a diagram showing an example of operation of the battery management device 13. FIG. 7 is a diagram illustrating another operational example of the battery management device 13. FIG. 20 is a flowchart illustrating processing performed by the battery management device 13 in the system configuration of FIG. 19.

<Embodiment 1>
FIG. 1 is a schematic diagram showing a configuration example of a storage battery system. A storage battery system includes a battery system including one or more storage batteries, and a battery management device that manages the battery system. In the following, we assume that the battery is a storage battery.

The battery system includes a battery module. A battery module is made up of one or more submodules. The submodule includes a battery cell and a sensor group. The sensor group includes, 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 can be constituted by a thermocouple, for example. The detection unit acquires measurement results from the sensor and transmits them to the battery management module (BMU). The BMU outputs measurement data describing the measurement results to the battery management device.

The battery management device includes a detection unit that acquires measurement data, a calculation unit that manages the state of the battery, a storage unit that stores data, and the like. The calculation unit estimates the state of the battery using the measurement data acquired from the BMU. For example, as explained below, the remaining life of the battery (or the degree of wear used to estimate the remaining life) can be estimated.

FIG. 2 shows the change in battery voltage over time during a rest period after a charging or discharging operation. Although the battery voltage after the discharging operation is illustrated here, a similar change over time can be observed even after the charging operation. The battery voltage during the rest period has a voltage change ΔVa in a relatively early first period (time length Δt1) and a voltage change ΔVb in a relatively late second period (time length Δt2). . ΔVa is a response component due to a component with a small time constant in the equivalent circuit of the battery, such as a response due to internal resistance or a negative electrode. ΔVb is a response component due to a component having a large time constant in the equivalent circuit of the battery, such as a response due to a positive electrode or a diffused resistance.

As a result of studies by the present 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, according to the procedure described below, a deterioration mode is estimated using ΔVa and ΔVb (or their rate of change over time), and an Eyring plot corresponding to the deterioration mode is used to estimate battery wear. We decided to estimate the state.

FIG. 3 is a graph showing the relationship between ΔVa and ΔVb. For batteries with a low deterioration rate, when ΔVa and ΔVb are plotted as shown in FIG. 3, the plots are concentrated around a certain threshold value. On the other hand, studies conducted by the present inventors have revealed that for batteries with a high rate of deterioration, these plots exist in a region equal to or higher than the threshold value. Therefore, in the present invention, based on whether these plots are equal to or higher than a threshold value, it is estimated whether the battery deteriorates in a mode in which the rate of deterioration of the battery is high or low.

The plot of ΔVa and ΔVb may be shown in either the upper or lower part of FIG. 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, a battery with a high deterioration rate is plotted in a region exceeding the threshold on the vertical axis, as shown by the black circle in FIG. In other words, it can be determined that a battery whose plot exceeds the threshold value on the vertical axis in FIG. 3 has a high rate of deterioration.

FIG. 4 is a schematic diagram showing an example of selecting an Eyring plot corresponding to a battery deterioration mode. The storage unit of the battery management device stores data describing Eyring plots for each battery deterioration mode (deterioration rate). The calculation unit estimates the deterioration rate of the battery and selects an Eyring plot corresponding to the deterioration rate from the data. The calculation unit estimates the degree of wear of the battery using the Eyring plot according to a procedure described later.

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

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 from, for example, the BMU. The calculation unit plots these as shown in FIG. If the plot exceeds the threshold, the deterioration rate of the battery is estimated to be A (relatively large), and if it is below the threshold, the deterioration rate is estimated to be B (relatively small). Additionally, the plot may be compared with the lower threshold. In this case, it is estimated which of A to C (relatively the smallest) the deterioration rate is.

FIG. 6 is a schematic diagram showing the procedure for determining the degree of battery wear using the battery condition and Eyring plot. Based on the battery measurement results, plots corresponding to the vertical and horizontal axes of the Eyring plot are obtained. By comparing the plot with the Eyring plot selected in FIG. 5, the degree of battery wear was estimated.

If the plot obtained from the battery measurement results is on the Eyring plot (or a predetermined shaded area near the Eyring plot) (Fig. 6 (i)), the battery is not in a worn state (in a normal state). ). If the plot obtained from the measurement results of the battery is outside the predetermined range (FIG. 6(ii)), it is assumed that the battery is not in a worn state, but that deterioration will progress if the current operating state is continued. In this case, as will be described later, the operating conditions of the battery may be readjusted. If the plot obtained from the measurement results of the battery deviates further from the predetermined range (FIG. 6(iii)), the battery is estimated to be in a worn state.

Since the intercept of the Eyring plot corresponds to the SOH, the upper and lower limits of the range in which the battery is considered normal on the Eyring plot can also be determined based on the upper and lower limits of the SOH. However, if a battery whose SOH has significantly decreased is plotted on an Eyring plot, it may fall within this normal range. This is considered to be due to a decrease in SOH due to causes other than wear. That is, as a result of studies conducted by the present inventors, it has been found that it may not be appropriate to determine whether or not a wear state exists using only SOH. Therefore, in the present invention, it is determined whether or not the wear state is present based on the degree of deviation from the normal range on the Eyring plot.

For example, if the distance from the normal range (shaded range) to the plot point on the two-dimensional coordinate space in FIG. 6 is equal to or greater than the first threshold, the battery is in the state shown in FIG. 6 (iii) (worn state). It is determined that there is. If the distance from the normal range to the plot point is less than the first threshold and greater than or equal to the second threshold (second threshold ≦ distance < first threshold), the battery is in the state shown in Figure 6 (ii) (deterioration will progress if operated as is). (state).

FIG. 7 is a diagram illustrating the procedure for determining the current number of cycles of the battery. When creating an Eyring plot or when plotting the actual measurement results of a battery on the created Eyring plot, it is necessary to find the number of charge/discharge cycles that the battery has performed so far (the current number of cycles). Therefore, in the present invention, the current cycle number is determined by the following procedure.

The SOH of a battery is defined, for example, by the amount of discharge current when fully discharged from full charge. In this case, SOH can be defined by the absolute value of the amount of discharge current. There is a relationship between the amount of discharge current and the number of cycles as shown in the lower part of FIG. That is, in a normal battery, the amount of discharge current does not easily decrease as the number of cycles progresses, whereas in a battery that has progressed with deterioration, the amount of discharge current decreases as the number of cycles progresses.

According to the relationship shown in the lower part of FIG. 7, it can be seen that the larger the decrease in the amount of discharge current, the more the deterioration progresses. Then, the current cycle number can be expressed as a function proportional to the reciprocal of the amount of decrease in the amount of discharge current from the normal state (capacity fade amount). That is, the following formula holds true: Current cycle number=a/capacity fade amount+b. The value on the vertical axis when the current state of the battery is plotted on the Eyring plot (that is, the value on the vertical axis of the white circle in FIG. 7) can be determined using this formula.

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 included in the battery management device. This flowchart is for determining the degree of battery wear based on the principle explained above. Each step in FIG. 8 will be explained below.

The calculation unit obtains ΔVa and ΔVb explained 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 for acquiring these measurement data are not limited to the above.

The calculation unit estimates the deterioration rate of the battery using the method described in FIGS. 3 to 5, and selects the Eyring plot corresponding to the estimated deterioration rate. Data describing the Eyring plot is stored in advance in a storage unit included 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 FIGS. 3 to 5, and the slope corresponding to the deterioration mode is specified.

The calculation unit obtains the result of measuring or estimating the SOH of the battery. The SOH can be estimated, for example, by referring to data describing the correspondence between ΔVa, ΔVb, their time change rates, and the SOH described in FIG. 2. Alternatively, the SOH measurement results may be obtained from an external device such as a BMU. SOH corresponds to the intercept of the Eyring plot. By specifying the slope and intercept of the Eyring plot, the calculation unit can select the Eyring plot corresponding to the deterioration mode.

The calculation unit plots the current state of the battery on the selected Eyring plot. Specifically, the difference between the current temperature of the battery and the standard temperature may be set as ΔT, and the current number of cycles determined by the method described in FIG. 7 may be set as N, and the values may be plotted on the Eyring plot. The calculation unit further estimates the degree of wear of the battery based on the distance between the Eyring plot and the plot of the current state of the battery, according to the method described in FIG.

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 operation method (deterioration mitigation operation mode) for suppressing the progression of battery deterioration. For example, if the degree of wear on the battery corresponds to the middle row in FIG. 6, it is considered that further deterioration can be suppressed by using an operation method that suppresses the progress of deterioration. If the wear is at the level shown in the upper row of FIG. 6, normal operation may be continued. If the wear is at the level shown in the lower part of FIG. 6, an alert may be output to prompt replacement, for example.

As an example of an operation method for suppressing the progression of battery deterioration, it is possible to set at least one of the following limits: Set at least one of an upper limit or a lower limit for battery voltage; Allowable battery temperature and at least either an upper limit or a lower limit of the SOC.

FIG. 10 shows changes in the battery condition due to the adoption of an operation method that suppresses the progression of battery deterioration. When the current state of the battery deviates from the Eyring plot (upper row of Figure 10), by adopting an operation method that suppresses the progress of battery deterioration, the battery state deviates from the Eyring plot (or near the Eyring plot). (within a predetermined range). This can prevent further deterioration of the battery and extend its remaining life.

FIG. 11 is an example of a data table that describes the results of battery diagnosis performed by the battery management device. For each battery to be diagnosed, the battery management device records the measurement data obtained from the BMU, etc., the degree of wear determined by the flowchart in Figure 9 (whether or not to change the operation method), etc. on a data table, and stores the data in the storage unit. It may be stored in .

FIG. 12 is a configuration diagram of the battery system 1. The battery system 1, battery controller (BMU) 12, and battery management device 13 are those illustrated in FIG. The battery system 1 includes a host controller 11, a battery controller (BMU) 12, and a battery management device 13. The host controller 11 outputs operation instructions for the battery via the battery controller 12. The battery controller 12 controls the battery modules according to the instructions. The battery management device 13 includes 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 storage unit 133 that stores data used by the calculation unit 132.

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

<Embodiment 2>
When the battery system is composed of a plurality of batteries, the degree of wear of the battery system as a whole may be determined. In this case, as in the first embodiment, the degree of wear of the battery system as a whole can be determined by plotting the current state of each battery on the Eyring plot. Therefore, in Embodiment 2 of the present invention, an example of the operation of a battery management device that diagnoses the state of the battery system as a whole will be described. The configurations of the battery system and battery management device are the same as in the first embodiment.

FIG. 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 shown in the middle row of Figure 14, an operation method that suppresses the progression of deterioration is adopted, and if there are many batteries that deviate significantly from the Eyring plot, as shown in the bottom row of Figure 14, , it may be determined that the battery system as a whole is in a worn out state. An example of using a Weibull plot will be described below as a procedure for diagnosing the state of the battery system as a whole.

FIG. 15 is a schematic diagram showing the procedure for creating an Eyring plot for the entire battery system. Eyring plots can be created for each battery, but since a battery system is made up of multiple batteries, the following procedure is used to create a single Eyring plot for the entire battery system.

The calculation unit acquires the measurement data of the battery voltage of each battery from, for example, the BMU, and selects the Eyring plot of each battery using the method described in the first embodiment. The calculation unit selects the Eyring plot for the battery system as a whole by specifying, from among these Eyring plots, the Eyring plot in which all the 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 battery system as a whole.

FIG. 16 is a histogram showing the results of counting the degree of deviation between the threshold value and the Eyring plot for each individual battery. By determining the degree of deviation between the Eyring plot of the entire battery system and the threshold value, it is possible to understand variations in the degree of battery wear and out-of-group conditions. The arithmetic unit creates a Weibull plot, which will be described below, using a battery whose degree of wear deviates from the Eyring plot of the entire system, which is represented by this histogram.

By using statistical values such as those shown in FIG. 16, it is possible to statistically calculate out-of-group batteries that have a large deviation from the threshold value in the battery system. In particular, even if the SoH calculated using the amount of discharge current is low and the battery appears to be worn out at first glance, by using the Eyring plot, it is possible to determine that the battery can still be used as a whole in the battery system. . On the other hand, even if the SoH calculated using the amount of discharge current is high and the battery 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. .

FIG. 17 is a flowchart illustrating the operation of the battery management device according to the second embodiment. Similar to the first embodiment, the calculation unit plots the current battery measurement results on the Eyring plot. When implementing this flowchart for a battery system, this Eyring plot is a single Eyring plot selected for the entire battery system, as explained in FIG. 16.

When the measurement results of each battery are plotted on the Eyring plot, the calculation unit identifies plots that deviate from the normal range (that is, correspond to the rightmost column in FIG. 16). The calculation unit creates a Weibull plot using the measurement results of the deviating battery. For example, the horizontal axis is the logarithm of the elapsed time from the start of operation, and the vertical axis is the logarithm of the cumulative defective rate. Whether or not a defective state has been reached can be determined from the SOH value. A Weibull plot can be obtained by plotting the measurement results of batteries that deviate from the normal range on both axes. Since the Weibull plot has temporal elements such as elapsed time and cumulative failure rate, it should be added that the battery measurement data acquired by the calculation unit in this flowchart is a history over time.

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 deviant battery. The calculation unit estimates that the battery system is in a worn state when the shape parameter m of the Weibull distribution exceeds 1. If m is less than or equal to 1, it is determined that the device can be operated within an appropriate operating range.

According to the second embodiment, even if the SOH of the battery system as a whole has deteriorated, it can be statistically determined that there is no problem with the battery system as a whole as long as the stress is moderate. If it is estimated that the battery system as a whole is becoming increasingly worn, countermeasures can be taken, such as changing the operating conditions of the battery system as in FIG. 9, or replacing the battery that is significantly worn.

<Embodiment 3>
FIG. 18 is a diagram showing an example of operation of the battery management device 13. The detection unit 131 acquires measured values such as battery voltage, battery temperature, battery current, C rate, and SOC of each battery module (or battery cell) or their history from the BMU, and records them in the storage unit 133. Using the data, the calculation unit 132 estimates the degree of battery wear using the method described in Embodiment 1, and changes the operating method as necessary (adopting an operating method that can suppress deterioration). can. Thereby, progress of deterioration of the battery can be suppressed.

For example, when transmitting the power generated by a power generation system including a battery system over a power company's power transmission network, a power transmission plan is created in advance and sent to the power company the day before the power transmission, and immediately before power transmission starts on the day the power transmission is carried out. It is conceivable to diagnose the degree of battery wear within a short period of time. In such a case, the diagnostic method according to the present invention is useful in that the diagnosis can be completed in a short time.

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

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 executed 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 the 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 out state but will continue to deteriorate if operated as they are (middle row in FIG. 6, middle row in FIG. 14), the operation method will be changed to one that suppresses the progress of deterioration. For batteries that have reached a worn out state (lower row in FIG. 6, lower row in FIG. 14), the time until they become unusable may be further estimated.

<About modifications of the present invention>
The present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-described embodiments have been described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

In the above embodiments, the start time of ΔVb is after the start time of ΔVa, and the end time of ΔVb is after the end time of ΔVa. As long as this relationship is maintained, for example, Δt1 (first period) and Δt2 (second period) may partially overlap.

In the embodiments described above, the detection unit 131 and the calculation unit 132 can be configured by hardware such as a circuit device implementing the function, or software implementing the function can be configured by a calculation unit such as a CPU (Central Processing Unit). It can also be configured by the device executing it.

13: Battery management device 131: Detection section 132: Arithmetic section 133: Storage section

Claims

A battery management device that manages battery status,
a detection unit that obtains a detected value of the voltage output by the battery;
a storage unit that stores data describing an Eyring plot of the battery for each deterioration 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 finishes a charging operation or a discharging operation,
The calculation unit selects the Eyring plot corresponding to the estimated deterioration mode,
The battery management device, wherein the calculation unit diagnoses the state of the battery based on the selected plot.
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 measured values of the battery are plotted on the same coordinate space as the Eyring plot. The battery management device according to claim 1, characterized in that:
The calculation unit calculates the distance between the selected Eyring plot and the measured value on the coordinate space as the degree of deviation,
The battery management device according to claim 2, wherein the calculation unit diagnoses that the battery is worn out when the degree of deviation is greater than or equal to a first threshold value.
The calculation unit controls the battery to operate the battery in a deterioration mitigation operation mode that alleviates progression of deterioration of the battery when the degree of deviation is less than the first threshold value and greater than or equal to the second threshold value. The battery management device according to claim 3, characterized in that:
The deterioration mitigation operation mode is
setting an upper threshold or a lower threshold of 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 starting the deterioration mitigation operation mode;
setting an upper threshold or a lower threshold for the state of charge of the battery;
The battery management device according to claim 4, wherein the battery management device is at least one of the following.
The deterioration mitigation operation mode is configured to extend the remaining life of the battery by changing the operating state of the battery such that the degree of deviation is less than the second threshold value. The battery management device according to claim 4.
The calculation unit obtains, as a capacity fade amount, an amount by which the capacity of the battery decreases by performing a charging operation or a discharging operation of the battery once,
The calculation unit calculates the number of charging or discharging cycles performed by the battery according to a function proportional to the reciprocal of the capacity fade amount,
The battery management device according to claim 2, wherein the calculation unit plots the cycle number as the measured value on the coordinate space.
The calculation unit selects the single Eyring plot for a battery system configured by a plurality of the batteries,
The calculation unit identifies, among the batteries constituting the battery system, those whose degree of deviation from the Eyring plot is equal to or greater than a threshold value as a deviant battery;
The calculation unit calculates a Weibull plot of the cumulative failure rate of the deviant battery and the operating time of the deviant battery,
The battery management device according to claim 1, wherein the calculation unit diagnoses the state of the battery system based on the shape parameter of the Weibull plot.
The battery is installed 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 voltage history and the state of charge history from the history storage unit,
The battery management device according to claim 1, wherein the calculation unit diagnoses the state of the battery using the acquired history and controls operating conditions of the battery according to the result.
The battery is installed in an electric device that operates using the output from the battery as power,
The battery management device according to claim 1, wherein the calculation unit acquires the change in voltage from the motorized device or a measuring device connected to the motorized device.
The battery is installed in an electric device that operates using the output from the battery as power,
The calculation unit obtains the voltage change from the motorized device or a measuring device connected to the motorized device,
The battery management device according to claim 8, wherein the calculation unit controls operating conditions of the battery according to the shape parameter.
The calculation unit determines the slope of the Eyring plot based on the activation energy of the battery,
The battery management device according to claim 1, wherein the calculation unit selects the Eyring plot whose slope has been determined as the Eyring plot corresponding to the estimated deterioration mode.
The calculation unit determines the intercept of the Eyring plot based on the health state of the battery,
The battery management device according to claim 1, wherein the calculation unit selects the Eyring plot for which the intercept has been determined as the Eyring plot corresponding to the estimated deterioration mode.
A battery management method for managing battery status, the method comprising:
obtaining a detected value of the voltage output by the battery;
estimating the state of the battery using data describing an Eyring plot of the battery for each deterioration mode of the battery;
has
In the estimating step, a deterioration mode of the battery is estimated based on a change in the voltage over time during a rest period after the battery finishes a charging operation or a discharging operation,
In the estimating step, selecting the Eyring plot corresponding to the estimated deterioration mode,
A battery management method characterized in that, in the estimating step, the state of the battery is diagnosed based on the selected plot.
A battery management program that causes a computer to execute processing for managing the state of a battery, the program comprising:
obtaining a detected value of the voltage output by the battery;
estimating the state of the battery using data describing an Eyring plot of the battery for each deterioration mode of the battery;
run the
In the estimating step, the computer executes 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 finishes charging or discharging;
In the estimating step, the computer executes a step of selecting the Eyring plot corresponding to the estimated deterioration mode,
A battery management program characterized in that, in the estimating step, the computer executes a step of diagnosing the state of the battery based on the selected plot.