Estimation device, diagnosis device, method for estimation, and method for diagnosis

Abstract

To provide an estimation device for estimating the whole discharge characteristics of a power storage element, a diagnosis device for diagnosing the capacitance of the power storage element on the basis of the whole discharge characteristics, a method for estimation, and a method for diagnosis.SOLUTION: The estimation device includes: an acquisition unit for acquiring time-series data of the current and the voltage of a power storage element; an electric amount calculation unit for calculating the time-series data of an electric amount on the basis of the acquired time-series data of the current; a generation unit for generating a partial charge-discharge profile of the power storage element on the basis of the acquired time-series data of the voltage and the time-series data of the electric amount; and an estimation unit for estimating the whole charge characteristics of the power storage element on the basis of the partial charge-discharge profile.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an estimation device, a diagnosis device, an estimation method, and a diagnosis method. [Background technology]

[0002] Energy storage devices are widely used in uninterruptible power supplies, DC or AC power supplies included in stabilized power supplies, etc. In addition, the use of energy storage devices is expanding in large-scale power systems that store electricity generated by renewable energy or existing power generation systems.

[0003] It is known that repeated charging and discharging of energy storage elements causes deterioration, and the full charge capacity gradually decreases. Patent Document 1 discloses a technology for a full charge and discharge method in which some energy storage elements are removed from an energy storage system in which the energy storage elements are installed, the removed energy storage elements are charged to a fully charged state, and then the energy storage elements are fully discharged with a constant discharge current, thereby measuring the capacity of the energy storage elements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-20654 Summary of the Invention [Problem to be solved by the invention]

[0005] When using the full charge / discharge method, it is necessary to stop the operation of the energy storage system. It is also possible to use a limited portion (part of the operation pattern) of the energy storage system's operation data (operation pattern) that allows for capacity diagnosis of the storage elements without stopping the operation of the energy storage system. However, this method only provides partial discharge characteristics, making it difficult to improve the accuracy of capacity diagnosis.

[0006] The present invention aims to provide an estimation device that estimates the overall discharge characteristics of a storage element, and a diagnostic device, estimation method, and diagnostic method that diagnose the full charge capacity (or state of health) of a storage element based on the overall discharge characteristics. [Means for solving the problem]

[0007] An estimation device according to one aspect of the present invention includes an acquisition unit that acquires time series data of current and voltage of a storage element, an electrical quantity calculation unit that calculates time series data of electrical quantity based on the time series data of current acquired by the acquisition unit, a generation unit that generates a partial charge / discharge profile of the storage element based on the time series data of voltage acquired by the acquisition unit and the time series data of electrical quantity calculated by the electrical quantity calculation unit, and an estimation unit that estimates the overall discharge characteristics of the storage element based on the partial charge / discharge profile. [Effects of the Invention]

[0008] According to the above aspect, it is possible to estimate the overall discharge characteristics of the energy storage elements at a predetermined time point after the start of operation of the energy storage system without stopping the operation of the energy storage system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram illustrating the configuration of an estimation device and a diagnosis device. [Figure 2] FIG. 1 is a diagram illustrating a configuration of a remote monitoring system. [Figure 3] FIG. 2 is a diagram showing the configuration of a bank. [Figure 4] FIG. 10 is a diagram illustrating an example of current data. [Figure 5] FIG. 10 is a diagram illustrating an example of voltage data. [Figure 6] FIG. 10 is a diagram showing an example of a partial charge / discharge profile. [Figure 7] FIG. 10 is a diagram illustrating an example of correction of positive single-electrode characteristics using a first parameter. [Figure 8] FIG. 10 is a diagram illustrating an example of correction of positive single-electrode characteristics using a second parameter. [Figure 9]FIG. 10 is a diagram illustrating an example of correction of negative single-electrode characteristics using a third parameter. [Figure 10] FIG. 10 is a diagram illustrating a method for estimating a portion of the overall discharge characteristic that corresponds to a partial charge / discharge profile. [Figure 11] FIG. 10 is a diagram showing a method for estimating overall discharge characteristics by complementing portions other than the partial charge / discharge profile. [Figure 12] FIG. 10 is a diagram showing overall discharge curves before and after degradation. [Figure 13] FIG. 10 is a diagram illustrating a first example of a method for diagnosing the capacitance of a storage element. [Figure 14] FIG. 10 is a diagram illustrating a second example of a method for diagnosing the capacitance of a storage element. [Figure 15] FIG. 10 shows the results of diagnostic capacity. [Figure 16] 10 is a flowchart showing a processing procedure of the estimation device. [Figure 17] 10 is a flowchart showing a processing procedure of the diagnostic device. [Figure 18] FIG. 10 is a diagram showing an example of a plot of electrical quantity versus voltage. [Figure 19] FIG. 2 is a diagram illustrating an example of a divided region. [Figure 20] 10A and 10B are diagrams illustrating a first example of a method for calculating a representative electrical quantity and a representative voltage of a divided region. [Figure 21] FIG. 10 is a diagram showing an example of a partial charge / discharge profile in a required period. [Figure 22] 10A and 10B are diagrams illustrating a second example of a method for calculating a representative electrical quantity and a representative voltage of a divided region. [Figure 23] FIG. 10 is a diagram showing an example of generating a partial charge / discharge profile for successive periods spanning a plurality of successive required periods. [Figure 24] 10 is a flowchart showing a process for generating a partial charge / discharge profile according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The estimation device includes an acquisition unit that acquires time series data of the current and voltage of the storage element, an electrical quantity calculation unit that calculates time series data of the electrical quantity based on the time series data of the current acquired by the acquisition unit, a generation unit that generates a partial charge / discharge profile of the storage element based on the time series data of the voltage acquired by the acquisition unit and the time series data of the electrical quantity calculated by the electrical quantity calculation unit, and an estimation unit that estimates the overall discharge characteristics of the storage element based on the partial charge / discharge profile.

[0011] The estimation method acquires time series data of the current and voltage of a storage element, calculates time series data of the quantity of electricity based on the acquired time series data of the current, generates a partial charge / discharge profile of the storage element based on the acquired time series data of the voltage and the calculated time series data of the quantity of electricity, and estimates the overall discharge characteristics of the storage element based on the partial charge / discharge profile.

[0012] The acquisition unit of the estimation device acquires time series data of the current and voltage of the storage element. The time series data of the current and voltage is data when the storage element is being charged or discharged. The charging current or discharging current does not need to be constant. Furthermore, the range of the SOC (State of Charge) and voltage when charging, and the range of the SOC and voltage when discharging may be limited. The acquisition unit acquires time series data when the storage element is in an actual operating pattern (not in a state of shutdown or a specific operating pattern for capacity diagnosis). The time series data may be real-time data or historical data from a predetermined period in the past.

[0013] The electric quantity calculation unit calculates the time series data of the electric quantity based on the acquired time series data of the current. The electric quantity can be obtained by current integration. For example, the electric quantity Q(t) can be calculated by the formula {Q(t) = ΣI(t) Δt}.

[0014] The generating unit generates a partial charge / discharge profile of the energy storage element based on the acquired time-series data of voltage and the calculated time-series data of the amount of electricity. For example, the partial charge / discharge profile can be drawn by plotting the time-series data on a two-dimensional coordinate system with the amount of electricity on the horizontal axis and the voltage on the vertical axis. The partial charge / discharge profile uses the term "partial" to distinguish it from the entire discharge characteristic, and is a partial charge / discharge profile between the upper limit voltage and the lower limit voltage set for the energy storage element, or a partial charge / discharge profile between the upper limit SOC and the lower limit SOC set for the energy storage element.

[0015] The estimation unit estimates the overall discharge characteristics of the energy storage element based on the partial charge / discharge profile. The estimation unit may estimate the overall discharge characteristics of the energy storage element based on the positive electrode single-electrode characteristics, negative electrode single-electrode characteristics, and partial charge / discharge profile of the energy storage element. The positive electrode single-electrode characteristics are characteristics represented by a positive electrode discharge curve. The positive electrode discharge curve may be a plot of the amount of electricity and the potential corresponding to the amount of electricity, with the horizontal axis representing the amount of electricity and the vertical axis representing the potential. The negative electrode single-electrode characteristics are characteristics represented by a negative electrode discharge curve. The negative electrode discharge curve may be a plot of the amount of electricity and the potential corresponding to the amount of electricity, with the horizontal axis representing the amount of electricity and the vertical axis representing the potential. The difference between the potential of the positive electrode and the potential of the negative electrode is the voltage of the energy storage element. The overall discharge characteristics are, for example, a characteristic represented by a continuous discharge curve ranging from an upper limit voltage to a lower limit voltage set for the energy storage element, or a characteristic represented by a continuous discharge curve ranging from an upper limit SOC to a lower limit SOC set for the energy storage element.

[0016] The estimation unit adjusts at least one of the positive and negative single-electrode characteristics of the energy storage element so that the difference between the positive and negative single-electrode characteristics approaches (approximates) the partial charge / discharge profile. The overall discharge characteristics can be estimated from the difference between the adjusted positive and negative single-electrode characteristics.

[0017] With the above-described configuration, the overall discharge characteristics of the storage elements can be estimated based on time series data of current and voltage obtained under the actual operating pattern, without stopping the operation of the storage system or operating the storage system under a specific operating pattern for capacity diagnosis.

[0018] The estimation device may include a correction unit that corrects the positive electrode single-electrode characteristics and / or the negative electrode single-electrode characteristics so that a difference between the positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics approaches the partial charge / discharge profile. The correction unit may be a part of the estimation unit.

[0019] The correction unit corrects, for example, the effectiveness (utilization rate) of the positive electrode. Correcting the effectiveness corresponds to correcting an index indicating the amount of usable active material in the positive electrode. The correction unit corrects the capacity at the discharge start position of the positive electrode single-electrode characteristics. Specifically, the capacity at the discharge start position can be corrected by translating the discharge curve of the positive electrode along the axis indicating the capacity. Correcting the discharge start position corresponds to correcting an index indicating the oxidative decomposition of the electrolyte.

[0020] The correction unit corrects the capacity at the discharge start position of the negative electrode single-electrode characteristics. Specifically, the correction is made by translating the negative electrode discharge curve along the axis indicating the capacity. Correcting the discharge start position is equivalent to correcting the index indicating the growth of the SEI (Solid Electrolyte Interphase) film.

[0021] With the above-described configuration, it is possible to make the difference between the positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics closer to the partial charge / discharge profile.

[0022] The estimation device may include a complementing unit that complements the partially obtained overall discharge characteristic of the energy storage element.

[0023] The complementing unit can complement a portion of the overall discharge characteristic other than the partial charge / discharge profile. The complementing unit may be a part of the estimating unit.

[0024] The estimation unit can estimate the overall discharge characteristic by combining the discharge characteristic corresponding to the partial charge / discharge profile with the interpolated discharge characteristic.

[0025] The estimation device may include a plot generation unit that generates an electricity quantity-voltage plot of the energy storage element over a required period based on the time series data of voltage acquired by the acquisition unit and the time series data of the electricity quantity calculated by the electricity quantity calculation unit, and a representative value calculation unit that calculates a representative electricity quantity and a representative voltage that represent the electricity quantity and the voltage in each of divided regions obtained by dividing the electricity quantity-voltage plot generated by the plot generation unit by a predetermined electricity quantity width, and the generation unit may generate a partial charge / discharge profile for the required period based on the representative electricity quantity and the representative voltage for each of the divided regions calculated by the representative value calculation unit.

[0026] The plot generation unit may generate a plot of the quantity of electricity versus voltage of the storage element over a required period. For example, the plot of the quantity of electricity versus voltage can be created by plotting time-series data of the quantity of electricity and voltage on a two-dimensional coordinate system with the horizontal axis representing the quantity of electricity and the vertical axis representing the voltage. The required period may be an appropriate period such as one day, one week, one month, three months, or six months, and may be set based on, for example, a period in which the operation pattern of the storage element does not vary significantly, or a period in which the calculation error of the quantity of electricity when calculating the quantity of electricity by integrating the current does not exceed an allowable range.

[0027] The electricity vs. voltage plot generated by the plot generation unit is divided into divided regions by a specified width of electricity. For example, an electricity vs. voltage plot drawn on a two-dimensional coordinate system with the horizontal axis representing electricity and the vertical axis representing voltage is divided into divided regions by dividing the electricity by a specified width of electricity. The divided regions are vertically long rectangular regions with the specified width of electricity on the horizontal direction and voltage on the vertical direction. In each divided region, a portion of the electricity vs. voltage plot is plotted.

[0028] The representative value calculation unit may calculate a representative electric quantity and a representative voltage representing the electric quantity and the voltage for each divided region from the electric quantity-voltage plot for each divided region. The representative electric quantity and the representative voltage may be calculated, for example, as follows.

[0029] The first method may be to use the average value of the voltage shown in the plot of the electric quantity versus voltage in the divided region as the representative voltage, and the center of the electric quantity range of the divided region as the representative electric quantity. The second method may be to plot the voltage versus current in the divided region, and use the voltage value at which the current value of the approximate curve (e.g., approximate straight line) of the plot is 0 as the representative voltage, and use the center of the electric quantity range of the divided region as the representative electric quantity.

[0030] The generating unit may generate a partial charge / discharge profile of the required period based on the representative quantity of electricity and the representative voltage for each divided region. The partial charge / discharge profile can be drawn by plotting the representative quantity of electricity and the representative voltage for each divided region on a two-dimensional coordinate system with the quantity of electricity on the horizontal axis and the voltage on the vertical axis.

[0031] The above-described configuration makes it possible to generate a partial charge / discharge profile for a required period (for example, a period in which the operation pattern of the storage elements does not vary significantly, or a period in which the calculation error of the amount of electricity does not exceed an allowable range).

[0032] The generating unit of the estimation device may generate a partial charge / discharge profile for a consecutive period of a plurality of consecutive required periods based on the partial charge / discharge profiles for each of the consecutive required periods.

[0033] The generating unit may generate a partial charge / discharge profile for each of a plurality of consecutive required periods, and generate a partial charge / discharge profile for a consecutive period of the plurality of required periods based on the generated partial charge / discharge profiles. For example, the consecutive required periods may be a first period and a second period. The operation patterns of the energy storage elements may not differ significantly between the first period and the second period, or the calculation error of the amount of electricity when calculating the amount of electricity by integrating the current may not exceed an allowable range. However, the operation patterns of the energy storage elements may differ significantly between the first period and the second period, or the calculation error of the amount of electricity may exceed an allowable range. In such a case, the partial charge / discharge profile for the consecutive period of the first period and the second period may be generated using the partial charge / discharge profiles generated for the first period and the second period, thereby enabling accurate generation of the partial charge / discharge profile without being affected by changes in the operation patterns of the energy storage elements or by calculation errors of the amount of electricity.

[0034] The estimation device may include a profile correction unit that corrects at least one of the first partial charge / discharge profile and the second partial charge / discharge profile by moving it along an electrical quantity axis on the partial charge / discharge profile so that a first partial charge / discharge profile in one of the consecutive required periods and a second partial charge / discharge profile in the other period approach each other, and the generation unit may generate the partial charge / discharge profile for the consecutive periods based on the correction made by the profile correction unit.

[0035] The profile correction unit corrects at least one of the first partial charge / discharge profile and the second partial charge / discharge profile by moving it along the electric quantity axis on the partial charge / discharge profile, thereby making the first partial charge / discharge profile and the second partial charge / discharge profile closer to each other on the partial charge / discharge profile. This makes it possible to reduce the deviation between the partial charge / discharge profiles in one period and the other of the consecutive required periods, for example, due to an error in calculating the electric quantity, and generate a partial charge / discharge profile with a connecting period longer than the required period.

[0036] The diagnosing device includes a diagnosing unit that diagnoses the full charge capacity of the storage element based on the overall discharge characteristic estimated by the above-mentioned estimation device.

[0037] The diagnostic method acquires time series data of the current and voltage of a storage element, calculates time series data of the amount of electricity based on the acquired time series data of the current, generates a partial charge / discharge profile of the storage element based on the acquired time series data of the voltage and the calculated time series data of the amount of electricity, estimates the overall discharge characteristics of the storage element based on the positive electrode single-electrode characteristics and negative electrode single-electrode characteristics of the storage element and the partial charge / discharge profile, and diagnoses the full charge capacity of the storage element based on the estimated overall discharge characteristics.

[0038] The diagnostic unit of the diagnostic device diagnoses the full charge capacity of the storage element based on the overall discharge characteristic estimated by the estimation device. The full charge capacity (diagnosed capacity) of the storage element can be calculated by subtracting the amount of electricity corresponding to the upper limit voltage from the amount of electricity corresponding to the lower limit voltage of the overall discharge characteristic.

[0039] With the above-described configuration, the full charge capacity of the storage element can be diagnosed based on the actual operation pattern without stopping the operation of the storage system or operating it in a specific operation pattern for capacity diagnosis.

[0040] The diagnostic device may include a statistical value calculation unit that calculates a statistical value of full charge capacities over a plurality of periods using the full charge capacities of the storage elements diagnosed by the diagnosis unit for each period; a determination unit that determines whether the full charge capacities for each period diagnosed by the diagnosis unit are valid or invalid using the statistical value calculated by the statistical value calculation unit; and a capacity calculation unit that calculates the full charge capacity of the storage elements over a required period, excluding the full charge capacities determined to be invalid by the determination unit.

[0041] The statistical value calculation unit calculates a statistical value of the full charge capacity over a plurality of periods using the full charge capacity of the storage element diagnosed by the diagnosis unit for each period. For example, the diagnosis unit diagnoses the full charge capacity for period A (e.g., one day), and calculates a statistical value of the full charge capacity for period B across a plurality of periods A. For example, periods A1, A2, A3, A4, and A5 can be collectively defined as period B. The statistical value may be, for example, a moving average R and standard deviation σ of the full charge capacity. If the full charge capacities diagnosed in periods A1 to A5, respectively, are Q1 to Q5, the moving average R can be calculated as R=(Q1+Q2+Q3+Q4+Q5) / 5. The standard deviation σ can be calculated as σ=√{Σ(Qi-R) 2 / 5}.

[0042] The determination unit uses the calculated statistical value to determine whether the full charge capacity for each period diagnosed by the diagnosis unit is valid or invalid. For example, if the diagnosed full charge capacity is within the range of average R±σ, it is determined to be valid, and if it is outside that range, it is determined to be invalid.

[0043] The capacity calculation unit calculates the full charge capacity of the storage element for the required period C, excluding the full charge capacity determined to be invalid. Required period C is longer than period B.

[0044] With the above-described configuration, highly accurate capacity diagnosis can be performed even when the usage state of the storage element (for example, the ratio of time spent charging, discharging, and resting, the SOC usage range, etc.) differs from period to period or when there is a bias.

[0045] Hereinafter, embodiments of an estimation device, a diagnosis device, an estimation method, and a diagnosis method will be described with reference to the drawings.

[0046] First Embodiment FIG. 1 is a diagram showing the configurations of an estimation device 50 and a diagnosis device 70. The estimation device 50 and the diagnosis device 70 are connected to a communication network 1. The estimation device 50 and the diagnosis device 70 may be integrated into either the estimation device 50 or the diagnosis device 70. A remote monitoring system 100 is connected to the communication network 1. The number of remote monitoring systems 100 may be one or three or more. The estimation device 50 and the diagnosis device 70, or either one of them, may be integrated into any of the remote monitoring systems 100. The estimation device 50 and the diagnosis device 70 will be described later.

[0047] 2 is a diagram showing the configuration of a remote monitoring system 100. The remote monitoring system 100 includes a communication device 10, a server device 20 connected to the communication device 10 via a communication network 2, a domain management device 30, and a power storage unit (domain) 40. The power storage unit 40 may include multiple banks 41. The power storage unit 40 is housed in a battery panel, for example, and is used in thermal power generation systems, mega solar power generation systems, wind power generation systems, uninterruptible power supplies (UPS), stabilized power supply systems for railways, and the like. The portion of the power storage unit 40 excluding a power conditioner (not shown) is sometimes referred to as a storage battery system.

[0048] The business operator designs, installs, operates, and maintains a power storage system including a communication device 10, a domain management device 30, and a power storage unit 40, and can remotely monitor the power storage system using the remote monitoring system 100.

[0049] The communication device 10 includes a control unit 11, a storage unit 12, a first communication unit 13, and a second communication unit 14. The control unit 11 is configured with a CPU (Central Processing Unit) and the like, and controls the entire communication device 10 using built-in memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0050] For example, a nonvolatile memory such as a flash memory can be used as the storage unit 12. The storage unit 12 can store required information, for example, information obtained by processing by the control unit 11.

[0051] The first communication unit 13 can communicate with the domain management device 30 (or the battery management device 44 shown in FIG. 3).

[0052] The second communication unit 14 is capable of communicating with the server device 20 via the communication network 2.

[0053] The domain management device 30 transmits and receives information to and from each bank 41 using a predetermined communication interface.

[0054] The storage unit 12 can store operational data acquired via the domain management device 30 .

[0055] The server device 20 can collect operation data of the power storage system from the communication device 10. The operation data includes time-series data such as current data, voltage data, and temperature data of each power storage element in the power storage system. The operation data may also include SOC (state of charge) data that can be calculated from the time-series data. The server device 20 stores the collected operation data by dividing it into sections for each power storage element. The server device 20 can transmit the operation data to the estimation device 50 via the communication networks 2 and 1. Note that the communication networks 1 and 2 may be a single communication network.

[0056] 3 is a diagram showing the configuration of the bank 41. The bank 41 is made up of a plurality of power storage modules connected in series, and includes a battery management unit (BMU) 44, a plurality of power storage modules 42, and a measurement board (CMU: Cell Management Unit) 43 provided in each power storage module 42.

[0057] The energy storage module 42 has multiple energy storage cells connected in series. In this specification, the term "energy storage element" may refer to an energy storage cell, an energy storage module 42, a bank 41, or a domain in which the banks 41 are connected in parallel. In this embodiment, the measurement board 43 acquires energy storage element information related to the state of each energy storage cell of the energy storage module 42. The energy storage element information includes, for example, the voltage, current, temperature, SOC (state of charge), and SOH of the energy storage cell. The energy storage element information can be acquired repeatedly at appropriate intervals, such as 0.1 seconds, 0.5 seconds, or 1 second. Accumulated data of the energy storage element information becomes part of the operational data. The "energy storage element" is preferably a secondary battery such as a lead-acid battery or a lithium-ion battery, or a rechargeable device such as a capacitor. Some of the energy storage elements may be non-rechargeable primary batteries.

[0058] The battery management device 44 can communicate with the measurement board 43 equipped with a communication function via serial communication, and can acquire information about the energy storage elements detected by the measurement board 43. The battery management device 44 can send and receive information to and from the domain management device 30. The domain management device 30 aggregates the energy storage element information from the battery management devices 44 of the banks belonging to the domain. The domain management device 30 outputs the aggregated energy storage element information to the communication device 10. In this way, the communication device 10 can acquire operational data about the energy storage units 40 via the domain management device 30.

[0059] 1, the estimation device 50 includes a control unit 51 that controls the entire device, a communication unit 52, a storage unit 53, an electric quantity calculation unit 54, a generation unit 55, an estimation unit 56, a correction unit 57, and a complementation unit 58. The control unit 51 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The storage unit 53 is composed of a hard disk, a semiconductor memory, etc., and stores required data.

[0060] The communication unit 52 includes a communication module and has a communication function between the diagnostic device 70 and the remote monitoring system 100 (server device 20). The communication unit 52 functions as an acquisition unit and acquires time-series data of the current and voltage of the energy storage element in the remote monitoring system 100. The time-series data of the current and voltage is data when the energy storage element is being charged or discharged. For example, the charging current or discharging current does not need to be constant. The range of the State of Charge (SOC) and voltage when charging, and the range of the SOC and voltage when discharging may be limited. Here, limited means that the range from the upper limit to the lower limit of the voltage or SOC is not included. The communication unit 52 acquires time-series data when the energy storage element is in an actual operating state (not in an out-of-operation state or in a specific operating state for capacity diagnosis). The time-series data may be real-time data or historical data.

[0061] FIG. 4 is a diagram showing an example of current data, and FIG. 5 is a diagram showing an example of voltage data. In FIG. 4, the vertical axis represents current, with the positive side representing charging and the negative side representing discharging. The horizontal axis represents time. The estimation device 50 acquires time-series current data as shown in FIG. 4. In FIG. 5, the vertical axis represents voltage and the horizontal axis represents time. The estimation device 50 acquires time-series voltage data as shown in FIG. 5.

[0062] The storage unit 53 shown in FIG. 1 stores the time-series data acquired via the communication unit 52.

[0063] The electricity quantity calculation unit 54 calculates time series data of the electricity quantity based on the time series data of the current acquired via the communication unit 52. The electricity quantity can be obtained by current integration. For example, the electricity quantity Q(t) can be calculated by the formula {Q(t)=ΣI(t)·Δt}.

[0064] The generating unit 55 generates a partial charge / discharge profile of the storage element based on the time series data of the voltage acquired via the communication unit 52 and the time series data of the amount of electricity calculated by the amount of electricity calculating unit 54.

[0065] Fig. 6 is a diagram showing an example of a partial charge / discharge profile (a state in which plots obtained for each predetermined period are superimposed). In Fig. 6, the horizontal axis represents the amount of electricity (Ah) and the vertical axis represents the voltage (V). A partial charge / discharge profile can be drawn by plotting the amount of electricity calculated by the amount of electricity calculation unit 54 and the voltage at the time when the amount of electricity was obtained (the voltage corresponding to the amount of electricity).

[0066] 1 estimates the overall discharge characteristics of the energy storage element based on the positive electrode single-electrode characteristics and negative electrode single-electrode characteristics of the energy storage element and the partial charge / discharge profile (see FIG. 6) generated by the generation unit 55. The overall discharge characteristics may be, for example, a characteristic indicated by a continuous discharge curve between an upper limit voltage and a lower limit voltage set for the energy storage element, or a characteristic indicated by a continuous discharge curve between an upper limit SOC and a lower limit SOC set for the energy storage element, but are not limited thereto.

[0067] Correction unit 57 may correct the positive electrode single-electrode characteristic so that the difference between the positive electrode single-electrode characteristic and the negative electrode single-electrode characteristic approaches the partial charge / discharge profile generated by generation unit 55. Estimation unit 56 may estimate the overall discharge characteristic of the energy storage element using the corrected positive electrode single-electrode characteristic.

[0068] Correction unit 57 may correct the negative single-electrode characteristic so that the difference between the positive single-electrode characteristic and the negative single-electrode characteristic approaches the partial charge / discharge profile generated by generation unit 55. Estimation unit 56 may estimate the overall discharge characteristic of the energy storage element using the corrected negative single-electrode characteristic. The positive single-electrode characteristic and the negative single-electrode characteristic will be described below.

[0069] FIG. 7 is a diagram showing an example of correction of positive electrode single-electrode characteristics using a first parameter. The positive electrode single-electrode characteristics are represented by a discharge curve of a positive electrode (e.g., a lithium counter electrode). The positive electrode discharge curve is a plot of the discharged amount of electricity (Ah) on the horizontal axis and the potential (V) on the vertical axis, with the discharged amount of electricity and the corresponding potential. The first parameter is positive electrode effectiveness (also referred to as "utilization rate"). The positive electrode effectiveness is an index indicating the amount of active material available in the positive electrode. FIG. 7 shows three positive electrode discharge curves P1, P2, and P3. The positive electrode discharge curves P1, P2, and P3 correspond to positive electrode effectiveness of 1, 0.9, and 0.8, respectively. When the positive electrode effectiveness is 1, the energy storage element is as good as new, and as deterioration progresses, the positive electrode effectiveness decreases. As shown in FIG. 7, the positive electrode single-electrode characteristics are corrected so that the positive electrode discharge curve is scaled along the horizontal axis according to the positive electrode effectiveness (first parameter).

[0070] FIG. 8 shows an example of correction of the positive electrode single-electrode characteristics using a second parameter. The second parameter is the discharge start position of the positive electrode. The discharge start position of the positive electrode is an index showing the oxidative decomposition of the electrolyte. FIG. 8 shows three positive electrode discharge curves P1, P4, and P5. The positive electrode discharge curves P1, P4, and P5 correspond to the relative discharge start positions (shifts from 0 Ah to the negative side) of 0 Ah, -5 Ah, and -10 Ah, respectively. As shown in FIG. 8, the positive electrode single-electrode characteristics are corrected so that the positive electrode discharge curve is shifted in the horizontal direction in accordance with changes in the relative discharge start position.

[0071] FIG. 9 is a diagram showing an example of correction of the negative electrode single-electrode characteristics using the third parameter. The negative electrode single-electrode characteristics are represented by a discharge curve of a negative electrode (e.g., a lithium counter electrode). The negative electrode discharge curve is a plot of the discharged amount of electricity (Ah) on the horizontal axis and the potential (V) on the vertical axis, with the discharged amount of electricity and the corresponding potential. The difference between the potential of the positive electrode and the potential of the negative electrode represents the voltage of the energy storage element. The third parameter is the discharge start position of the negative electrode. The discharge start position of the negative electrode is an index indicating the growth of the SEI (Solid Electrolyte Interphase) coating. FIG. 9 shows three negative electrode discharge curves N1, N2, and N3. The negative electrode discharge curves N1, N2, and N3 correspond to the relative discharge start positions (shift from 0 Ah to the negative side) of 0 Ah, -5 Ah, and -10 Ah, respectively. As shown in FIG. 9, the negative electrode unipolar characteristics are corrected so that the negative electrode discharge curve is translated in the horizontal direction in response to changes in the relative position of the start of discharge.

[0072] The positive single-electrode characteristic, the negative single-electrode characteristic, and the first to third parameters may be stored in the storage unit 53.

[0073] By using the above-described configuration, it is possible to make the difference between the positive electrode single electrode characteristics and the negative electrode single electrode characteristics closer to the partial charge / discharge profile.

[0074] Correction unit 57 corrects at least one of the positive and negative single-electrode characteristics of the energy storage element so that the difference between the positive and negative single-electrode characteristics approaches the partial charge / discharge profile generated by generation unit 55. Estimation unit 56 can estimate the overall discharge characteristics from the difference between the corrected positive and negative single-electrode characteristics.

[0075] With the above-described configuration, it is possible to estimate the overall discharge characteristics of the energy storage elements based on time-series data of current and voltage obtained in an actual operating state, without stopping the operation of the energy storage system or without charging and discharging the energy storage system in a specific operating pattern for capacity diagnosis. The method for estimating the overall discharge characteristics will be specifically described below.

[0076] FIG. 10 is a diagram showing a method for estimating the portion of the overall discharge characteristics corresponding to the partial charge / discharge profile. In FIG. 10, the horizontal axis represents the quantity of electricity (Ah), and the vertical axis represents the voltage / potential (V). FIG. 10A shows the partial charge / discharge profile S, the positive electrode discharge curve Px, and the negative electrode discharge curve Nx. By adjusting the first and second parameters described above, the shape of the positive electrode discharge curve Px can be adjusted to correct the positive electrode single-electrode characteristics. Furthermore, by adjusting the third parameter, the shape of the negative electrode discharge curve Nx can be adjusted to correct the negative electrode single-electrode characteristics.

[0077] At least one of the first to third parameters is adjusted to adjust at least one of the positive electrode discharge curve Px and the negative electrode discharge curve Nx so that the difference between the potential corresponding to a certain amount of electricity on the positive electrode discharge curve Px and the potential corresponding to that amount of electricity on the negative electrode discharge curve Nx approaches the potential corresponding to that amount of electricity on the partial charge / discharge profile S. The difference between the potential corresponding to a certain amount of electricity on the positive electrode discharge curve Px and the potential corresponding to that amount of electricity on the negative electrode discharge curve Nx is the voltage corresponding to that amount of electricity on the entire discharge curve (specifically, the portion Qa corresponding to the partial charge / discharge profile S).

[0078] For example, as shown in an enlarged view in FIG. 10B, the sum of squares of the voltage difference ΔVi between the voltage corresponding to a certain amount of electricity in the partial charge / discharge profile S and the voltage corresponding to the amount of electricity in the portion Qa of the entire discharge curve corresponding to the partial charge / discharge profile S (ΣΔVi 2 The first to third parameters are calculated so that the sum of squares is minimized. Here, the voltages corresponding to all the electrical quantities on the partial charge / discharge profile S may be used.

[0079] FIG. 11 is a diagram showing a method for estimating the overall discharge characteristics by complementing portions other than the partial charge / discharge profile. The complementing unit 58 complements the overall discharge characteristics of the energy storage element from the difference between the positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics for capacity ranges other than the capacity range corresponding to the partial charge / discharge profile. As described above, by adjusting at least one of the positive electrode discharge curve Px and the negative electrode discharge curve Nx so that the difference between the positive electrode discharge curve Px and the negative electrode discharge curve Nx approaches the partial charge / discharge profile S, the discharge curve Qa can be estimated for the capacity range corresponding to the partial charge / discharge profile S. For capacity ranges other than the capacity range corresponding to the partial charge / discharge profile S, the discharge curve Qb is complemented from the difference between the adjusted positive electrode discharge curve Px and negative electrode discharge curve Nx. The overall discharge curve can be estimated by connecting the discharge curve Qa and the discharge curve Qb.

[0080] FIG. 12 is a diagram showing total discharge curves before and after degradation. FIG. 12A shows an example of a total discharge curve Q of an initial storage element estimated by the estimation device 50, and FIG. 12B shows an example of a total discharge curve Q' of a storage element after degradation estimated by the estimation device 50. In FIG. 12A, the total discharge curve Q is estimated based on an uncorrected (unadjusted) positive electrode discharge curve Px and an uncorrected negative electrode discharge curve Nx. By changing at least one of the first to third parameters described above for the positive electrode discharge curve Px and the negative electrode discharge curve Nx in consideration of the degradation of the storage element, the post-degradation positive electrode discharge curve Px' and the post-degradation negative electrode discharge curve Nx' can be obtained as shown in FIG. 12B. The post-degradation total discharge curve Q' is estimated based on the positive electrode discharge curve Px' and the negative electrode discharge curve Nx'.

[0081] As described above, by appropriately adjusting the first to third parameters, it is possible to estimate the overall discharge characteristics that match the partial charge / discharge profile.

[0082] Next, the diagnostic device 70 will be described. As shown in Fig. 1, the diagnostic device 70 includes a control unit 71 that controls the entire device, a communication unit 72, a storage unit 73, a diagnostic unit 74, a statistical value calculation unit 75, a determination unit 76, and a capacity calculation unit 77. The control unit 71 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The storage unit 73 is composed of a hard disk, a semiconductor memory, etc., and stores required data.

[0083] The communication unit 72 acquires data relating to the overall discharge characteristics of the storage elements estimated by the estimation device 50.

[0084] The diagnosing unit 74 diagnoses the capacity of the storage element based on the overall discharge characteristic estimated by the estimating device 50.

[0085] Fig. 13 is a diagram showing a first example of a method for diagnosing the full charge capacity of a storage element. In Fig. 13, the horizontal axis represents capacity (Ah) and the vertical axis represents voltage (V). The overall discharge characteristic (reproduced overall discharge curve) estimated by estimation device 50 reproduces a continuous discharge curve from the upper limit voltage to the lower limit voltage set for the storage element. The full charge capacity (diagnosed capacity) of the storage element can be calculated by subtracting the capacity corresponding to the upper limit voltage from the capacity (electrical quantity) corresponding to the lower limit voltage of the overall discharge curve.

[0086] With the above-described configuration, the full charge capacity of the storage element can be diagnosed without stopping the operation of the storage element (or without operating it in a specific operating pattern for capacity diagnosis), even when the storage element is operating in an actual operating pattern.

[0087] The usage state of a storage element varies depending on the period (e.g., day by day, time of day, etc.). Specifically, the proportion of time spent charging, discharging, and resting, and the range of SOC (SOC region) in which the storage element is used may differ. For example, if only the proportion of time spent charging is extremely high, the voltage of the discharge characteristic of the storage element will be high. If there are days during a relatively long period (e.g., one week, one month, etc.) when the usage state is extremely uneven, the accuracy of the capacity diagnosis value may decrease. Below, we will explain how to solve this problem.

[0088] FIG. 14 is a diagram showing a second example of a method for diagnosing the full charge capacity of a storage element. This method is based on the premise that the full charge capacity of a storage element does not change significantly over a period of about one week or one month. In FIG. 14, periods A, B, and C are used as examples. Period A is, for example, a period equivalent to one day, but may be a time period instead of one day. Period B is made up of multiple periods A, with period B being greater than period A. In the example of FIG. 14, five periods A are combined into period B. Multiple periods B are set by shifting the periods B by the unit of period A. Period C is a longer period than period B. In the example of FIG. 14, period C is made up of seven periods A, but it may also be made up of a number of periods A other than seven.

[0089] The statistical value calculation unit 75 calculates statistical values ​​of the full charge capacities over a plurality of periods using the full charge capacities of the storage elements diagnosed by the diagnosis unit for each period. For example, the diagnosis unit 74 diagnoses the full charge capacity for period A, and calculates statistical values ​​of the full charge capacities for period B across a plurality of periods A. The statistical values ​​may be, for example, a moving average R and standard deviation σ of the full charge capacities. If the full charge capacities diagnosed in each of the five periods A are Q1 to Q5, the moving average R can be calculated as R=(Q1+Q2+Q3+Q4+Q5) / 5. The standard deviation σ can be calculated as σ=√{Σ(Qi-R) 2 / 5}.

[0090] The determination unit 76 determines whether the full charge capacity diagnosed by the diagnosis unit 74 for each period A is valid or invalid using the statistical values ​​calculated by the statistical value calculation unit 75. The determination of validity or invalidity is made, for example, by determining that the diagnosed full charge capacity is valid if it is within the range of average R±σ, and determining that it is invalid if it is outside the range.

[0091] The capacity calculation unit 77 calculates the full charge capacity of the storage element over the required period C, excluding the full charge capacity that the determination unit 76 has determined to be invalid.

[0092] Fig. 15 shows the results of the diagnostic capacity. As shown in Fig. 15, the true capacity (true value of the fully charged capacity) is set to 50.4 (Ah). When the outliers (fully charged capacities determined to be invalid) were excluded, the diagnostic capacity was 50.6 (Ah), whereas the diagnostic capacity including the outliers (diagnosed value of the fully charged capacity) was 47.3 (Ah).

[0093] As described above, highly accurate capacity diagnosis can be performed even when the usage state of the storage element (for example, the ratio of time spent charging, discharging, and resting, the SOC usage range, etc.) differs for each period or when there is a bias.

[0094] 16 is a flowchart showing the processing procedure of the estimation device 50. For convenience, the following description will be given assuming that the processing is performed by the control unit 51. The control unit 51 acquires time-series data of the current and voltage of the energy storage element (S11) and generates a partial charge / discharge profile (S12). The control unit 51 corrects the positive single-electrode characteristics so that the difference between the positive single-electrode characteristics and the negative single-electrode characteristics approaches the partial charge / discharge profile (S13), and corrects the negative single-electrode characteristics so that the difference between the positive single-electrode characteristics and the negative single-electrode characteristics approaches the partial charge / discharge profile (S14).

[0095] The control unit 51 determines whether the difference between the positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics and the partial charge / discharge profile is within an allowable range (S15). If the difference is not within the allowable range (NO in S15), the control unit 51 continues the processing from step S13 onwards. If the difference is within the allowable range (YES in S15), the control unit 51 estimates discharge characteristics corresponding to the partial charge / discharge profile (S16).

[0096] The control unit 51 complements the discharge characteristics other than the discharge characteristics corresponding to the partial charge / discharge profile based on the difference between the corrected positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics (S17), estimates the overall discharge characteristics of the storage element based on the discharge characteristics corresponding to the partial charge / discharge profile and the complemented discharge characteristics (S18), and terminates the processing.

[0097] 17 is a flowchart showing the processing procedure of the diagnostic device 70. For convenience, the following description will be given with the control unit 71 as the main body of the processing. The control unit 71 diagnoses the full charge capacity of the storage element based on the estimated overall discharge characteristics (S31). The control unit 71 diagnoses the full charge capacity for each period A (S32), and calculates the average value (moving average) and standard deviation of the full charge capacity for each period B (> period A) (S33).

[0098] The control unit 71 determines whether the full charge capacity diagnosed in period A is within a predetermined range (S34). The predetermined range can be determined by a moving average and a standard deviation. If the full charge capacity diagnosed in period A is within the predetermined range (YES in S34), the control unit 71 determines that the full charge capacity diagnosed in period A is a valid value (S35), and performs the processing of step S37 described below.

[0099] If the full charge capacity diagnosed in period A is not within the predetermined range (NO in S34), the control unit 71 determines that the full charge capacity diagnosed in period A is an outlier (invalid) (S36), and performs averaging processing for period C using only valid full charge capacity values ​​(S37). The control unit 71 sets the averaged full charge capacity value as the full charge capacity for period A (S38), and ends the processing.

[0100] The estimation device 50 and the diagnosis device 70 may be integrated into one device. For example, the electrical quantity calculation unit 54, the generation unit 55, the estimation unit 56, the correction unit 57, and the complementation unit 58 of the estimation device 50 may be incorporated into the diagnosis device 70.

[0101] As described above, according to the present embodiment, it is possible to provide a technology for diagnosing the full charge capacity of a storage element without stopping its operation or operating it in a specific operation pattern for capacity diagnosis. This technology can also be applied to deteriorated storage elements. Furthermore, even if the usage state of the storage element varies over time, it is possible to provide highly accurate capacity diagnosis results.

[0102] Second Embodiment The operation pattern (way of use) of a storage element may vary depending on the period (e.g., one day, one week, one month, three months, six months, etc.), and when diagnosing the full charge capacity of a storage element, if the operation pattern varies within the diagnosis period, the accuracy of the diagnosis may decrease. In the second embodiment, a method for generating a partial charge / discharge profile will be described so that the full charge capacity can be accurately diagnosed even when the operation pattern of the storage element varies depending on the period. In the second embodiment, the generation unit 55 has the functions of a plot generation unit, a representative value calculation unit, and a profile correction unit.

[0103] FIG. 18 is a diagram showing an example of an electricity quantity versus voltage plot (Ah-V plot). In FIG. 18, the horizontal axis represents the electricity quantity (Ah), and the vertical axis represents the voltage (V). The generation unit 55 may generate an electricity quantity versus voltage plot PL of the storage element over a required period (period Ai in FIG. 18) based on the time-series data of voltage acquired via the communication unit 52 and the time-series data of the electricity quantity calculated by the electricity quantity calculation unit 54. The electricity quantity versus voltage plot (Ah-V plot) PL can be drawn, for example, by plotting the time-series data of the electricity quantity and voltage on a two-dimensional coordinate system with the electricity quantity on the horizontal axis and the voltage on the vertical axis. The required period can be an appropriate period such as one day, one week, one month, three months, or six months. For example, the required period may be set based on a period in which the operation pattern of the storage element does not vary significantly, or a period in which the calculation error of the electricity quantity when calculating the electricity quantity by integrating the current does not exceed an allowable range.

[0104] FIG. 19 is a diagram showing an example of divided regions. The generation unit 55 divides the generated (Ah-V plot) PL into divided regions by dividing it by a predetermined width of the electric quantity. As shown in FIG. 19, the (Ah-V plot) PL drawn on a two-dimensional coordinate system with the horizontal axis representing the electric quantity (Ah) and the vertical axis representing the voltage (V) is divided into divided regions by dividing the electric quantity by a predetermined width of the electric quantity (ΔPL in FIG. 19). The divided regions are vertically elongated rectangular regions with the horizontal direction representing the predetermined width of the electric quantity ΔPL and the vertical direction representing the voltage (V). In each divided region, a portion of the (Ah-V plot) PL is plotted. In FIG. 19, (Ah-V plots) PL1 and PL2 are plotted in the divided region ΔPL.

[0105] 20 is a diagram showing a first example of a method for calculating a representative quantity of electricity and a representative voltage of a divided region. The generation unit 55 may calculate a representative quantity of electricity and a representative voltage that represent the quantity of electricity and voltage for each divided region from the (Ah-V plot) in each divided region. For the representative quantity of electricity and the representative voltage, for example, the average value of the voltage represented by the (Ah-V plot) in the divided region may be used as the representative voltage, and the center of the width of the quantity of electricity of the divided region may be used as the representative quantity of electricity.

[0106] As shown in Fig. 20, if the voltages of PL1 and PL2 in the divided region (Ah-V plot) are Vi (i = 1 to n), the representative voltage V may be calculated as the average of the voltages Vi. If the electrical quantities at both ends of the divided region are Qn and Q(n+1), the representative electrical quantity Q may be calculated as the center value of the electrical quantity range {Q(n+1)-Qn}.

[0107] Fig. 21 is a diagram showing an example of a partial charge / discharge profile for a required period. The generation unit 55 may generate the partial charge / discharge profile for a required period based on the representative quantity of electricity Q (bar) and the representative voltage V (bar) for each divided region. As shown in Fig. 21, the partial charge / discharge profile (Ah-OCV characteristics) can be depicted by plotting the representative quantity of electricity and the representative voltage (indicated by symbol X in Fig. 21) for each divided region on a two-dimensional coordinate system with the quantity of electricity on the horizontal axis and the voltage on the vertical axis.

[0108] The above-described configuration makes it possible to generate a partial charge / discharge profile for a required period (for example, a period in which the operation pattern of the storage elements does not vary significantly, or a period in which the calculation error of the amount of electricity does not exceed an allowable range).

[0109] The method for calculating the representative voltage V(bar) is not limited to the example shown in FIG.

[0110] FIG. 22 is a diagram showing a second example of a method for calculating the representative quantity of electricity and the representative voltage of a divided region. As shown in FIG. 22, the voltage V versus the current I of PL1 and PL2 within the divided region (Ah-V plot) is plotted on a two-dimensional voltage-current coordinate system. The voltage value (i.e., intercept b) at which the current value of a curve approximating the plot (in FIG. 22, a straight line V=a×I+b) is 0 may be taken as the representative voltage V(bar). If the quantities of electricity at both ends of the divided region are Qn and Q(n+1), the representative quantity of electricity Q(bar) may be taken as the center value of the range of quantities of electricity {Q(n+1)-Qn}.

[0111] Next, generation of a partial charge / discharge profile for a continuous period spanning a plurality of consecutive required periods (the entire period spanning a plurality of required periods) will be described.

[0112] The generation unit 55 may generate a partial charge / discharge profile for each of a plurality of consecutive required periods, and then generate a partial charge / discharge profile for a consecutive period of a plurality of consecutive required periods based on the generated partial charge / discharge profiles. For example, the consecutive required periods may be a first period and a second period. The operation patterns of the storage elements may not differ significantly between the first period and the second period, or the calculation error of the amount of electricity when calculating the amount of electricity by integrating the current may not exceed the allowable range. However, the operation patterns of the storage elements may differ significantly between the first period and the second period, or the calculation error of the amount of electricity may exceed the allowable range. In such a case, the partial charge / discharge profile for the consecutive period of the first period and the second period may be generated using the partial charge / discharge profiles generated for the first period and the second period, thereby enabling accurate generation of the partial charge / discharge profile without being affected by changes in the operation patterns of the storage elements or by calculation errors of the amount of electricity.

[0113] Fig. 23 shows an example of partial charge-discharge profiles generated over a series of consecutive required periods. Fig. 23A shows the Ah-OCV characteristics (partial charge-discharge profile) for period A1 and the Ah-OCV characteristics for period A2, which follows period A1. The Ah-OCV characteristics for period A1 and the Ah-OCV characteristics for period A2 differ (there is a discrepancy on the two-dimensional coordinate system of the amount of electricity and the voltage) due to various factors (e.g., changes in the operation pattern of the storage element, errors in calculating the amount of electricity, etc.).

[0114] The generation unit 55 corrects at least one of the (Ah-OCV characteristics) in period A1 (first partial charge-discharge profile) and the (Ah-OCV characteristics) in period A2 (second partial charge-discharge profile) by moving them along the electric quantity axis on the two-dimensional coordinate system of electric quantity and voltage, thereby making the (Ah-OCV characteristics) in period A1 closer to the (Ah-OCV characteristics) in period A2. In Fig. 23B, the (Ah-OCV characteristics) in period A2 are translated along the electric quantity axis to make the (Ah-OCV characteristics) in period A2 closer to the (Ah-OCV characteristics) in period A1.

[0115] As shown in FIG. 23C, the voltage V i,A and the voltage V (Ah-OCV characteristic) during period A2 i,B The residual d between the two is minimized. As a result, as shown in FIG. 23D, the (Ah-OCV characteristics) for period A1 and the (Ah-OCV characteristics) for period A2 may be combined to obtain a partial charge-discharge profile S for period (A1+A2). As a result, even if the partial charge-discharge profiles for one consecutive required period differ from those for the other consecutive required periods due to, for example, an error in calculating the amount of electricity, the difference can be reduced to generate a partial charge-discharge profile for a continuous period longer than the required period. In the example of FIG. 23, two consecutive periods are described, but partial charge-discharge profiles can also be generated in the same way when three or more consecutive required periods exist.

[0116] The partial charge / discharge profile generated in the second embodiment can be used to estimate the overall charge / discharge characteristics of the energy storage element by performing the same processing as in the first embodiment. Similarly, the full charge capacity of the energy storage element can also be diagnosed based on the estimated overall discharge characteristics.

[0117] 24 is a flowchart showing the procedure for generating a partial charge / discharge profile according to the second embodiment. The control unit 51 acquires time-series data of the current and voltage of the storage element during a period Ai (S41), integrates the acquired time-series data of the current, converts it into time-series data of the amount of electricity, and generates a plot of the voltage against the amount of electricity (Ah-V plot) (S42). The Ah-V plot is shown in FIG. 18.

[0118] The control unit 51 subdivides the (Ah-V plot) into divided regions with a predetermined width of the electric quantity (S43). The subdivision of the (Ah-V plot) is as shown in FIG. 19. The control unit 51 calculates the electric quantity and OCV in the subdivided divided regions (S44). Here, as shown in FIG. 20 or FIG. 22, a representative electric quantity and a representative voltage are calculated for each divided region.

[0119] The control unit 51 estimates the (Ah-OCV characteristics) for the period Ai based on the representative electrical quantity and representative voltage for each divided region (S45). The (Ah-OCV characteristics) for the period Ai are those exemplified in Fig. 21. The control unit 51 determines whether there is another period following the period Ai (S46), and if there is another period (YES in S46), adds 1 to i (S47) and continues the processing from step S41 onwards.

[0120] If there are no other periods (NO in S46), the control unit 51 combines the (Ah-OCV characteristics) of each of the consecutive periods Ai obtained so far in step S45 to generate a partial charge / discharge profile for the consecutive periods (S48), and ends the process. The process of step S48 is performed according to the procedure exemplified in FIG.

[0121] As described above, according to the second embodiment, even if the storage element is used differently for each period, the difference in the storage element's (Ah-OCV characteristics) for each period can be corrected to generate a partial charge / discharge profile for a continuous period spanning multiple periods, thereby improving the accuracy of diagnosing the full charge capacity of the storage element.

[0122] The present invention is intended to be illustrative and not restrictive in all respects, and the scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0123] 1, 2 Communication network 10. Communication Devices 11 Control section 12 Storage section 13 First Communications Department 14 Second Communications Department 20 Server device 30 Domain Management Device 40 Energy Storage Unit 41 Bank 42 Energy storage module 43 Measurement board 44 Battery management device 50 Estimation device 51 Control section 52 Communications Department 53 Storage section 54 Electrical quantity calculation unit 55 Generation part 56 Estimation part 57 Correction section 58 Complementary Section 70 Diagnostic Equipment 71 Control Unit 72 Communications Department 73 Memory section 74 Diagnostic Department 75 Statistical value calculation section 76 Judgment section 77 Capacity calculation section

Claims

1. an acquisition unit that acquires time-series data of current and voltage of the storage element; an electric quantity calculation unit that calculates time series data of an electric quantity based on the time series data of the current acquired by the acquisition unit; a generation unit that generates a partial charge / discharge profile of the energy storage element based on the time series data of the voltage acquired by the acquisition unit and the time series data of the amount of electricity calculated by the amount of electricity calculation unit; an estimation unit that estimates an overall discharge characteristic of the energy storage element based on the partial charge / discharge profile; An estimation device comprising:

2. the estimation unit estimates an overall discharge characteristic of the energy storage element based on a positive electrode single-electrode characteristic, a negative electrode single-electrode characteristic, and the partial charge / discharge profile of the energy storage element; The estimation device according to claim 1 .

3. a correction unit that corrects the positive electrode single-electrode characteristics and / or the negative electrode single-electrode characteristics so that a difference between the positive electrode single-electrode characteristics and the negative electrode single-electrode characteristics approaches the partial charge / discharge profile; The estimation device according to claim 2 .

4. A complementary portion is provided to complement the overall discharge characteristics of the partially obtained storage element. The estimation device according to any one of claims 1 to 3.

5. a plot generating unit that generates a plot of the electric quantity and voltage of the energy storage element over a required period based on the time series data of the voltage acquired by the acquiring unit and the time series data of the electric quantity calculated by the electric quantity calculating unit; a representative value calculation unit that calculates a representative electric quantity and a representative voltage that represent the electric quantity and the voltage in each divided region obtained by dividing the electric quantity / voltage plot generated by the plot generation unit by a predetermined electric quantity width; Equipped with The generation unit generating a partial charge / discharge profile for the required period based on the representative quantity of electricity and the representative voltage for each divided region calculated by the representative value calculation unit; The estimation device according to any one of claims 1 to 4.

6. The generation unit generating a partial charge / discharge profile for a consecutive period in which the plurality of required periods are consecutive, based on the partial charge / discharge profile for each of the consecutive required periods; The estimation device according to claim 5 .

7. a profile correction unit that corrects at least one of the first partial charge / discharge profile and the second partial charge / discharge profile by moving it along an electric quantity axis on the partial charge / discharge profile so that a first partial charge / discharge profile in one period of consecutive required periods and a second partial charge / discharge profile in the other period approach each other; The generation unit generating a partial charge / discharge profile for the consecutive periods based on the correction by the profile correction unit; The estimation device according to claim 6 .

8. a diagnosis unit that diagnoses the capacity of the storage element based on the overall discharge characteristic estimated by the estimation device according to any one of claims 1 to 7; Diagnostic equipment.

9. a statistical value calculation unit that calculates a statistical value of full charge capacities over a plurality of periods using the full charge capacities of the storage elements diagnosed by the diagnosis unit for each period; a determination unit that determines whether the full charge capacity for each period diagnosed by the diagnosis unit is valid or invalid using the statistical value calculated by the statistical value calculation unit; a capacity calculation unit that calculates a full charge capacity of the storage element over a required period, excluding the full charge capacity determined to be invalid by the determination unit; Equipped with The diagnostic device of claim 8.

10. Acquire time series data of the current and voltage of the storage element; Calculates time series data of the amount of electricity based on the acquired time series data of the current, generating a partial charge / discharge profile of the energy storage element based on the acquired time series data of the voltage and the calculated time series data of the amount of electricity; estimating an overall discharge characteristic of the energy storage element based on the partial charge / discharge profile; Estimation method.

11. Acquire time series data of the current and voltage of the storage element; Calculates time series data of the amount of electricity based on the acquired time series data of the current, generating a partial charge / discharge profile of the energy storage element based on the acquired time series data of the voltage and the calculated time series data of the amount of electricity; estimating an overall discharge characteristic of the energy storage element based on the partial charge / discharge profile; Diagnosing the full charge capacity of the storage element based on the estimated overall discharge characteristics; Diagnostic methods.

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