Estimation device, diagnostic device, estimation method, estimation program and diagnostic method

Abstract

This estimation device is provided with: an acquisition unit that acquires time-series data of a current and a voltage of a power storage element; a calculation unit that calculates time-series data of an electric quantity or SOC on the basis of the time-series data of the current acquired by the acquisition unit; a generation unit that generates a partial charge / discharge graph of the power storage element on the basis of the time-series data of the current acquired by the acquisition unit and the time-series data of the amount of power or SOC calculated by the calculation unit; and an estimation unit that estimates the overall discharge characteristics of the power storage element on the basis of a parameter indicating the internal state quantity of the power storage element, the parameter being adjusted such that a graph of a prescribed section in the overall discharge characteristics of the power storage element approaches the partial charge / discharge graph.

Description

Technical Field

[0001] The present invention relates to an estimation device, a diagnostic device, an estimation method, an estimation program, and a diagnostic method. Background Art

[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 in large-scale power systems that store electricity generated by renewable energy or existing power generation systems is expanding.

[0003] It is known that storage elements deteriorate due to repeated charging and discharging, and the full charge capacity gradually decreases. Patent document 1 and related documents disclose the following full charge and discharge method technology: a portion of the storage elements are removed from a storage system equipped with storage elements, and after the removed storage elements are charged to a full charge state, the storage elements are fully discharged with a certain discharge current, thereby measuring the capacity of the storage elements.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-121520 Summary of the invention

[0007] Problems to be solved by the invention

[0008] When the full charge and discharge method is adopted, the operation of the power storage system needs to be stopped. It is also considered to use a limited part (a part of the operation mode) that can perform capacity diagnosis of the power storage element from the operation data (operation mode) of the power storage system without stopping the operation of the power storage system. However, in this method, only partial discharge characteristics can be obtained, so it is difficult to improve the accuracy of capacity diagnosis.

[0009] A main object of the present disclosure is to provide an estimating device and the like that can estimate the overall discharge characteristics of an electric storage element with high accuracy.

[0010] Means for solving problems

[0011] An estimation device according to one embodiment of the present disclosure comprises: an acquisition unit for acquiring time series data of a current and a voltage of an electric storage element; a calculation unit for calculating time series data of an electric quantity or a SOC based on the time series data of the current acquired by the acquisition unit; a generation unit for generating a partial charge and discharge curve graph of the electric storage element based on the time series data of the current acquired by the acquisition unit and the time series data of the electric quantity or the SOC calculated by the calculation unit; and an estimation unit for estimating an overall discharge characteristic of the electric storage element based on a parameter representing an internal state quantity of the electric storage element, the parameter being adjusted so that a curve graph of a given interval in the overall discharge characteristic of the electric storage element is close to the partial charge and discharge curve graph.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to estimate the overall discharge characteristics of the power storage element with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing a configuration example of an estimation device and a diagnosis device.

[0015] Figure 2 It is a diagram showing the structure of a power generation system.

[0016] Figure 3 It is a diagram showing a structural example of a group.

[0017] Figure 4 : is a functional block diagram showing a configuration example of an estimation device.

[0018] Figure 5 This is a diagram showing an example of current data.

[0019] Figure 6 It is a diagram showing an example of voltage data.

[0020] Figure 7 It is a diagram showing an example of a partial charge and discharge graph.

[0021] Figure 8 : is a diagram showing another example of a partial charge and discharge graph.

[0022] Fig. 9 This is a diagram for explaining the internal state quantity parameters.

[0023] Fig.10 This is a diagram showing an example of the correspondence relationship between the discharge capacity of the power storage element and the internal state quantity parameter.

[0024] Fig.11 This is a diagram for explaining a method of estimating overall discharge characteristics.

[0025] Fig.12 This is a flowchart showing an example of a processing procedure executed by the estimation device and the diagnosis device.

[0026] Fig.13 This is a flowchart showing an example of a processing procedure executed by the estimation device according to the second embodiment. DETAILED DESCRIPTION

[0027] (1) An estimation device according to one aspect of the present disclosure includes: an acquisition unit that acquires time series data of a current and a voltage of an electric storage element; a calculation unit that calculates time series data of an electric quantity or a SOC (State of Charge) based on the time series data of the current acquired by the acquisition unit; a generation unit that generates a partial charge and discharge curve graph of the electric storage element based on the time series data of the current acquired by the acquisition unit and the time series data of the electric quantity or the SOC calculated by the calculation unit; and an estimation unit that estimates an overall discharge characteristic of the electric storage element based on a parameter representing an internal state quantity of the electric storage element, the parameter being adjusted so that a curve graph of a given interval in the overall discharge characteristic of the electric storage element approaches the partial charge and discharge curve graph.

[0028] The so-called "partial charge and discharge curve diagram" refers to a charge and discharge curve diagram of a portion in the storage element, and the word "partial" is used to distinguish it from the overall discharge characteristics. The partial charge and discharge curve diagram is a charge and discharge curve diagram of a portion between the upper limit voltage and the lower limit voltage set for the storage element, or a charge and discharge curve diagram of a portion between the upper limit SOC and the lower limit SOC set for the storage element.

[0029] The “overall discharge characteristic” refers to a characteristic represented by a continuous discharge curve between an upper voltage limit and a lower voltage limit set for the power storage element, or a characteristic represented by a continuous discharge curve between an upper SOC limit and a lower SOC limit set for the power storage element.

[0030] The “given interval” may refer to, for example, an interval corresponding to the capacity of a partial charge and discharge curve graph out of the full capacity in the overall discharge characteristics.

[0031] “Close to” may refer to, for example, a case where the difference between a graph of a given interval in the overall discharge characteristic and the partial charge and discharge graph is close to zero.

[0032] According to the above configuration, the overall discharge characteristics of the storage element can be estimated based on the time series data of the current and voltage obtained in the actual operation mode without stopping the operation of the storage system or operating the storage system in a specific operation mode for capacity diagnosis. In addition, according to the above configuration, by using appropriately adjusted parameters representing the internal state quantity of the storage element, the overall discharge characteristics can be estimated with high accuracy even in an area other than the voltage area or SOC area obtained in the actual operation mode. The overall discharge characteristics can be estimated with high accuracy regardless of the type of load applied to the storage element.

[0033] As described above, the estimation device estimates the overall discharge characteristics including other (all) voltage regions based on the partial charge and discharge curve diagram related to a portion of the voltage region (SOC region) obtained in the actual operation mode. Depending on the voltage region in the charge and discharge curve diagram, the estimation accuracy of the overall discharge characteristics may decrease. In other words, depending on the type of load applied to the storage element, the estimation accuracy of the overall discharge characteristics may decrease.

[0034] For example, when the obtained time series data is biased towards a specific voltage region (e.g., the inclined portion of the voltage), the region of the charge-discharge curve graph becomes narrower. In addition, even when the time series data within a relatively wide voltage range is obtained, when the charge-discharge current is unbalanced, the region in which the partial charge-discharge curve graph can be generated will also become narrower. When the overall discharge characteristics are estimated based on the partial charge-discharge curve graph involving such a local region, for example, in a voltage region far away from the voltage region of the partial charge-discharge curve graph, the shape of the estimated overall discharge characteristics may deviate from the actual (true value) shape of the overall discharge characteristics.

[0035] According to the above structure, the parameter representing the internal state quantity (hereinafter also referred to as the internal state quantity parameter) is adjusted so that the overall discharge characteristics are close to the partial charge and discharge curve diagram. The internal state quantity is an element that determines the overall shape of the overall discharge characteristics. Even in the case where only a partial charge and discharge curve diagram is obtained, the shape of the overall discharge characteristics can be appropriately expressed in the entire voltage range set for the storage element by using the internal state quantity parameter adjusted based on local information. The overall discharge characteristics can be estimated with high accuracy regardless of the type of load applied to the storage element.

[0036] (2) The estimation device described in (1) above may further include an adjustment unit configured to adjust the parameter based on a correspondence relationship between the capacity of the power storage element and the parameter.

[0037] The "capacity of a storage element" refers to the total amount of electricity present when the storage element is discharged from the fully charged state (SOC100%) to SOC0% at a certain current value. Hereinafter, the capacity of the storage element is also referred to as the discharge capacity. The discharge capacity becomes a unique value based on the overall discharge characteristics of the storage element. That is, the overall discharge characteristics close to the partial charge and discharge curve diagram is equivalent to the overall discharge characteristics close to the partial charge and discharge curve diagram representing a given discharge capacity.

[0038] When adjusting the internal state quantity parameters so that the overall discharge characteristics are adapted to the partial charge and discharge curve diagram, the number of values ​​of the internal state quantity parameters that may be candidates for adjustment is huge. In particular, when there are multiple types of internal state quantity parameters, there are multiple combinations of internal state quantity parameters that may be candidates for adjustment, so it is difficult to uniquely determine the solution, and the estimation accuracy decreases. In addition, the narrower the area of ​​the partial charge and discharge curve diagram, the less information is used to determine the charge and discharge curve diagram, so as mentioned above, the combination of internal state quantity parameters that may be candidates for adjustment also increases, so the adjustment operation of the internal state quantity parameters becomes more difficult.

[0039] According to the estimation device described in (2) above, the internal state quantity parameters can be efficiently determined by utilizing the correspondence between the discharge capacity and the internal state quantity parameters. By pre-calculating the values ​​of the internal state quantity parameters corresponding to the capacity of the storage element and storing their correspondence, the computational load during estimation can be reduced. For example, by storing the above correspondence for a plurality of internal state quantity parameters respectively, the combination of the internal state quantity parameter values ​​corresponding to one capacity value can be determined, thereby facilitating the adjustment process of the internal state quantity parameters and improving the estimation accuracy.

[0040] (3) In the estimation device described in (2), the adjustment unit may adjust the parameter so that a graph of a predetermined section of the overall discharge characteristic related to the capacity corresponding to the parameter approaches the partial charge and discharge graph.

[0041] According to the estimation device described in (3) above, by adjusting the capacity value represented by the overall discharge characteristic, the internal state quantity parameter can be easily adjusted based on the correspondence relationship with the capacity value.

[0042] (4) In the estimation device described in (2) or (3) above, a plurality of correspondence relationships may be set according to a state of the power storage element, and the adjustment unit may select a correspondence relationship used for determining the parameter according to the state of the power storage element.

[0043] According to the estimation device described in (4) above, it is possible to generate an overall discharge characteristic by taking into account the state of the storage element. The state of the storage element refers to the state of the storage element to date, for example, it can be a state related to the usage history or type of the storage element. The usage history of the storage element includes information such as the temperature range used by the storage element to date and the SOC range used. The type of storage element includes design information of the storage element. The correspondence between the capacity of the storage element and the internal state quantity depends on the state of the storage element. By determining the correspondence between the capacity of the storage element and the internal state quantity by taking into account the state transition of the storage element, the estimation accuracy of the overall discharge characteristic can be improved.

[0044] (5) In the estimation device described in any one of (2) to (4) above, the adjustment unit may generate the correspondence relationship based on the partial charge and discharge graph.

[0045] According to the estimation device described in (5) above, the correspondence relationship is obtained when the power storage element is operated, so there is no need to set the correspondence relationship in advance, and the overall discharge characteristics can be estimated more easily.

[0046] (6) In the estimation device described in any one of (1) to (5) above, the estimation unit may estimate the overall discharge characteristics of the energy storage element based on the parameter and the positive electrode single pole characteristics and negative electrode single pole characteristics of the energy storage element.

[0047] The “positive electrode unipolar characteristic” refers to the characteristic represented by the positive electrode discharge curve. The “negative electrode unipolar characteristic” refers to the characteristic represented by the negative electrode discharge curve. According to the estimation device described in (6), the overall discharge characteristic can be efficiently estimated based on the difference between the positive electrode unipolar characteristic and the negative electrode unipolar characteristic of the storage element corresponding to the adjusted internal state quantity parameter.

[0048] (7) In the estimation device described in any one of (1) to (6) above, the parameters may include positive electrode effectiveness and a charge retention amount of a negative electrode.

[0049] According to the estimation device described in (7) above, the shape of the overall discharge characteristic can be appropriately adjusted by adjusting the index representing the internal state of the power storage element.

[0050] (8) A diagnostic device according to one aspect of the present disclosure includes a processing unit that diagnoses the capacity of a power storage element based on the overall discharge characteristic estimated by the estimating device described in any one of (1) to (7).

[0051] According to the above configuration, the full charge capacity of the power storage element can be diagnosed based on the actual operation mode without stopping the power storage system or operating it in a specific operation mode for capacity diagnosis.

[0052] (9) An estimation method according to one aspect of the present disclosure performs the following processing by a computer: acquiring time series data of current and voltage of a storage element; calculating time series data of electric quantity or SOC based on the acquired time series data of current; generating a partial charge and discharge curve graph of the storage element based on the acquired time series data of current and the calculated time series data of electric quantity or SOC; estimating the overall discharge characteristics of the storage element based on a parameter representing an internal state quantity of the storage element, the parameter being adjusted so that a curve graph of a given interval in the overall discharge characteristics of the storage element is close to the partial charge and discharge curve graph.

[0053] (10) An estimation program according to one embodiment of the present disclosure causes a computer to execute the following processing: acquiring time series data of current and voltage of a storage element; calculating time series data of electric quantity or SOC based on the acquired time series data of current; generating a partial charge and discharge curve graph of the storage element based on the acquired time series data of current and the calculated time series data of electric quantity or SOC; estimating an overall discharge characteristic of the storage element based on a parameter representing an internal state quantity of the storage element, the parameter being adjusted so that a curve graph of a given interval in the overall discharge characteristic of the storage element is close to the partial charge and discharge curve graph.

[0054] (11) A diagnostic method according to one aspect of the present disclosure performs the following processing by a computer: acquiring time series data of current and voltage of a storage element; calculating time series data of electric quantity or SOC based on the acquired time series data of current; generating a partial charge and discharge curve graph of the storage element based on the acquired time series data of current and the calculated time series data of electric quantity or SOC; estimating an overall discharge characteristic of the storage element based on a parameter representing an internal state quantity of the storage element, the parameter being adjusted so that a curve graph of a given interval in the overall discharge characteristic of the storage element approaches the partial charge and discharge curve graph; and diagnosing the capacity of the storage element based on the estimated overall discharge characteristic.

[0055] Hereinafter, the present disclosure will be described in detail with reference to the drawings showing embodiments thereof.

[0056] (First embodiment)

[0057] Figure 11 is a diagram showing a configuration example of an estimation device 50 and a diagnostic device 70. The estimation device 50 and the diagnostic device 70 are connected to a communication network 1 such as the Internet for communication. The estimation device 50 and the diagnostic device 70 may be integrated into either the estimation device 50 or the diagnostic device 70. A power generation system 100 is connected to the communication network 1. The number of power generation systems 100 may be one or more than three. The estimation device 50 and the diagnostic device 70 or one of them may be integrated into any power generation system 100.

[0058] The estimation device 50 and the diagnosis device 70 are, for example, a server computer, a personal computer, a quantum computer, etc., and perform various information processing and information transmission and reception. The estimation device 50 and the diagnosis device 70 will be described in detail later.

[0059] Figure 2 1 is a diagram showing the structure of a power generation system 100. The power generation system 100 includes a communication device 10, a server device 20 connected to the communication device 10 via a network 2, a domain management device 30, and a power storage unit (domain) 40. The power storage unit 40 may include a plurality of groups 41. The power storage unit 40 is, for example, housed in a battery panel and is used in a thermal power generation system, a megawatt-class solar power generation system, a wind power generation system, an uninterruptible power supply (UPS: Uninterruptible Power Supply), a stabilized power supply system for railways, and the like. The portion of the power storage unit 40 other than the power conditioner not shown is sometimes also referred to as a battery system. The power storage unit 40 is not limited to industrial use, and may also be a power storage unit for household use.

[0060] The estimation device 50, the diagnostic device 70, and the plurality of power generation systems 100 constitute a remote monitoring system. The remote monitoring system is configured to be able to remotely access information related to the power storage elements included in the power generation system 100. A practitioner who designs, introduces, operates, and maintains a power storage system including the communication device 10, the domain management device 30, and the power storage unit 40 can remotely monitor the power storage system through the remote monitoring system.

[0061] 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 composed of a CPU (Central Processing Unit) and the like, and controls the entire communication device 10 using a built-in memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0062] The storage unit 12 includes, for example, a nonvolatile storage device such as a flash memory. The storage unit 12 can store necessary information, for example, information obtained by processing of the control unit 11.

[0063] The first communication unit 13 has a function of communicating with the domain management device 30 (or Figure 3 The control unit 11 can communicate with the domain management device 30 via the first communication unit 13 .

[0064] The second communication unit 14 includes a communication interface for realizing communication via the network 2. The control unit 11 can communicate with the server device 20 via the second communication unit 14.

[0065] The domain management device 30 uses a given communication interface to transmit and receive information with each group 41. The storage unit 12 can store operation data acquired via the domain management device 30.

[0066] The server device 20 can collect the operation data of the power storage system from the communication device 10. The operation data includes time series data such as the current value, voltage value, and temperature data of each power storage element in the power storage system. The server device 20 stores the collected operation data separately for each power storage element. The server device 20 can send the operation data to the estimation device 50 via the network 2, 1. In addition, the network 2, 1 can also be a communication network.

[0067] Figure 3 4 is a diagram showing a configuration example of a group 41. The group 41 is formed by connecting a plurality of storage modules in series, and includes a battery management unit (BMU) 44, a plurality of storage modules 42, and a measurement substrate (CMU: Cell Management Unit) 43 provided in each storage module 42.

[0068] The power storage module 42 connects a plurality of power storage cells in series. In this specification, "power storage element" may refer to a power storage cell, a power storage module 42, a group 41, or a domain formed by connecting the group 41 in parallel. In this embodiment, the measurement substrate 43 obtains power storage element information related to the state of each power storage cell of the power storage module 42. The power storage element information includes, for example, the voltage, current, temperature, SOC (State of Charge), SOH (State of Health), etc. of the power storage cell. The power storage element information can be repeatedly obtained at appropriate cycles such as 0.1 seconds, 0.5 seconds, and 1 second. The data storing the power storage element information becomes part of the operation data. "Power storage element" is preferably a rechargeable power storage element such as a secondary battery such as a lead-acid battery and a lithium-ion battery, or a capacitor. A part of the power storage element may also be a primary battery that cannot be recharged.

[0069] The battery management device 44 can communicate with the measurement substrate 43 with a communication function through serial communication, and can obtain the storage element information detected by the measurement substrate 43. The battery management device 44 can send and receive information with the domain management device 30. The domain management device 30 collects the storage element information from the battery management devices 44 of the group belonging to the domain. The domain management device 30 outputs the collected storage element information to the communication device 10. In this way, the communication device 10 can obtain the operation data of the storage unit 40 via the domain management device 30. The communication device 10 sends the obtained operation data to the estimation device 50 via the server device 20.

[0070] like Figure 1 As shown, the estimation device 50 includes a control unit 51, a storage unit 52, a communication unit 53, etc. The estimation device 50 may be a multi-computer composed of a plurality of computers, or may be a virtual machine virtually constructed by software.

[0071] The control unit 51 is a computing circuit including a CPU, a GPU (Graphics Processing Unit), a ROM, a RAM, etc. The CPU or GPU included in the control unit 51 executes various computer programs stored in the ROM and the storage unit 52 to control the operation of the above-mentioned hardware units. The control unit 51 may also include a timer for measuring the elapsed time from when a measurement start instruction is given to when a measurement end instruction is given, a counter for counting the number, a clock for outputting date and time information, and the like.

[0072] The storage unit 52 includes a nonvolatile storage device such as a flash memory and a hard disk drive. Various computer programs executed by the control unit 51 and data required for executing the computer programs are stored in the storage unit 52. The computer programs stored in the storage unit 52 include an estimation program 521 for causing a computer to execute processing related to estimation of the overall discharge characteristics.

[0073] The data stored in the storage unit 52 include operation data received from the power generation system 100 and corresponding information related to the correspondence between the discharge capacity of the storage element and the internal state quantity parameter. As described above, the operation data includes time series data of the current value and voltage value of the storage element in the power generation system 100. The corresponding information includes, for example, a correlation function, a corresponding table, or a corresponding graph indicating the relationship between the discharge capacity and the internal state quantity parameter. The corresponding information may also store a plurality of information corresponding to the state of the storage element.

[0074] The computer program (program product) including the estimation program 521 can be provided by a non-volatile recording medium 5A on which the computer program is readable. The recording medium 5A is a removable storage such as a CD-ROM, a USB memory, or an SD (Secure Digital) card. The control unit 51 uses a reading device not shown in the figure to read the desired computer program from the recording medium 5A and stores the read computer program in the storage unit 52. Alternatively, the above-mentioned computer program can also be provided through communication. The estimation program 521 can be composed of a single computer program or a plurality of computer programs, and can be executed on a single computer or on a plurality of computers connected to each other via a communication network.

[0075] The communication unit 53 includes a communication interface for realizing communication via the network 1. The control unit 51 can communicate with an external device through the communication unit 53. Examples of external devices that can be connected to the communication unit 53 in a communicative manner include the power generation system 100 and the diagnostic device 70. The control unit 51 receives operation data transmitted from the power generation system 100 through the communication unit 53. The control unit 51 transmits the estimated result of the overall discharge characteristic to the diagnostic device 70 through the communication unit 53.

[0076] The estimation device 50 may include, for example, an operation unit for accepting user operations, a display unit for displaying various information, and the like.

[0077] The diagnostic device 70 includes a control unit 71, a storage unit 72, a communication unit 73, a display unit 74, an operation unit 75, etc. The diagnostic device 70 may be a multicomputer composed of a plurality of computers, or a virtual machine virtually constructed by software.

[0078] The control unit (processing unit) 71 is a computing circuit including a CPU, a GPU, a ROM, a RAM, etc. The CPU or the GPU included in the control unit 71 executes various computer programs stored in the ROM and the storage unit 72 to control the operation of the above-mentioned hardware units. The control unit 71 may also include a timer for measuring the elapsed time from when a measurement start instruction is given to when a measurement end instruction is given, a counter for counting the number, a clock for outputting date and time information, and the like.

[0079] The storage unit 72 includes a nonvolatile storage device such as a flash memory and a hard disk drive. The storage unit 72 stores various computer programs executed by the control unit 71 and data required for executing the computer programs. The computer programs stored in the storage unit 72 include a diagnostic program 721 for causing a computer to execute processing related to the diagnosis of the discharge capacity.

[0080] The communication unit 73 includes a communication interface for realizing communication via the network 1. The control unit 71 can communicate with the estimation device 50 via the communication unit 73. The control unit 71 receives the estimation result of the overall discharge characteristic transmitted from the estimation device 50 via the communication unit 73.

[0081] The display unit 74 includes, for example, a display device such as a liquid crystal display or an organic EL (electroluminescence) display. The display unit 74 displays various information according to instructions from the control unit 71. The operation unit 75 is an interface for accepting user operations. The operation unit 75 includes, for example, a keyboard, a touch screen device built into the display, a speaker, and a microphone. The operation unit 75 accepts operation input from the user and sends a control signal corresponding to the operation content to the control unit 71.

[0082] The diagnostic device 70 may also be configured to receive an operation via an externally connected computer and output information to be notified to the external computer. In this case, the diagnostic device 70 may not include the display unit 74 and the operating unit 75.

[0083] Figure 4 is a functional block diagram showing a configuration example of the estimation device 50. The control unit 51 of the estimation device 50 realizes the functions of the acquisition unit 511, the calculation unit 512, the generation unit 513, the estimation unit 514, and the adjustment unit 515 by reading and executing the estimation program 521 stored in the storage unit 52. Alternatively, part of these functions may be realized by a dedicated hardware circuit (such as FPGA or ASIC) provided in the control unit 51.

[0084] The acquisition unit 511 acquires the time series data of the current and voltage of the storage element. The time series data of the current and voltage are data when the storage element is charged or discharged. The charging current or the discharging current does not have to be fixed. In addition, the SOC area or the voltage area during charging, and the SOC area or the voltage area during discharging can also be limited. The acquisition unit 511 acquires the time series data of the actual operation mode of the storage element (not the state of stopping operation, or not the specific operation mode for capacity diagnosis). The time series data can be real-time data or historical data of a given period in the past.

[0085] Figure 5 is a diagram showing an example of current data, Figure 6 It is a diagram showing an example of voltage data. Figure 5 The horizontal axis of the graph shown is time, and the vertical axis is current. On the vertical axis, the positive side represents charging, and the negative side represents discharging. The acquisition unit 511 acquires Figure 5 Time series current data as shown. Figure 6 The horizontal axis of the graph shown is time, and the vertical axis is voltage. Figure 6 The time-series voltage data as shown. The time-series data acquired by the acquisition unit 511 is stored in the storage unit 52.

[0086] The calculation unit 512 calculates the time series data of the electric quantity based on the time series data of the electric current acquired by the acquisition unit 511. The electric quantity can be obtained by integrating the electric current, and can be calculated by the following formula (1), for example.

[0087]

[0088] In formula (1), Q is the amount of electricity and I is the current value.

[0089] The generator 513 generates a partial charge and discharge graph of the power storage element based on the time series data of the voltage acquired by the acquirer 511 and the time series data of the electric quantity calculated by the calculator 512 .

[0090] Figure 7 It is a diagram showing an example of a partial charge and discharge graph. Figure 7 An example of a partial charge and discharge graph S is shown as a state in which plots obtained at predetermined intervals are superimposed. Figure 7 The horizontal axis of the graph shown is the electric quantity (Ah), and the vertical axis is the voltage (V). The generating unit 513 can draw a partial charge and discharge curve graph S by, for example, plotting the electric quantity calculated by the calculating unit 512 and the voltage at the time when the electric quantity is obtained (the voltage corresponding to the electric quantity) in a two-dimensional coordinate system with the horizontal axis being the electric quantity and the vertical axis being the voltage.

[0091] The generator 513 may generate a partial charge and discharge graph by performing a predetermined process on the above-mentioned electric quantity / voltage graph. Figure 8 : is a diagram showing another example of a partial charge and discharge graph. Figure 8 In the graph shown, the horizontal axis is the electric quantity (Ah), and the vertical axis is the voltage (V).

[0092] The generator 513 generates an electric quantity / voltage map (Ah-V map) PL of the power storage element within a required period based on the time series data of the voltage acquired by the acquirer 511 and the time series data of the electric quantity calculated by the calculator 512 . Figure 8 The hollow circle mark in represents the (Ah-V plot) PL. For example, the (Ah-V plot) PL can be drawn by plotting the time series data of the electric quantity and the voltage in a two-dimensional coordinate system with the horizontal axis being the electric quantity and the vertical axis being the voltage.

[0093] The required period can be set using appropriate periods such as 1 day, 1 week, 1 month, 3 months, 6 months, etc. For example, the period during which the operation mode (usage history) of the storage element is not much different, the period during which the error in calculating the amount of electricity when calculating the amount of electricity by accumulating the current does not exceed the allowable range, etc. can be used as references.

[0094] The generating unit 513 generates a power supply with a given power width (in Figure 8 The generated (Ah-V plot) PL is divided into the divided areas after the charge is divided (ΔPL in the figure). Figure 8 The figure shown on the right side of is an enlarged figure of the divided area represented by the rectangular frame in the graph.

[0095] The horizontal direction of the segmented area is a given charge width ΔPL, and the vertical direction is voltage (V), and it is a vertically long rectangular area. In each segmented area, a part of PL is plotted (Ah-V plot). Figure 8 , PL1 and PL2 are plotted in the divided region ΔPL (Ah-V plot).

[0096] The generating unit 513 calculates the representative electric quantity and the representative voltage representing the electric quantity and the voltage for each segmented area based on the (Ah-V plot) in each segmented area. Regarding the representative electric quantity and the representative voltage, for example, the average value of the voltage represented by the (Ah-V plot) in the segmented area can be used as the representative voltage, and the center of the electric quantity width of the segmented area can be used as the representative electric quantity.

[0097] The generating unit 513 generates a partial charge and discharge curve graph for a required period based on the representative electric quantity and the representative voltage of each divided area. Figure 8As shown by the cross mark in , a partial charge and discharge curve diagram (Ah-OCV characteristic) can be drawn by plotting the representative electric quantity and representative voltage of each segmented area in a two-dimensional coordinate system with the horizontal axis set as the electric quantity and the vertical axis set as the voltage. In this way, a partial charge and discharge curve diagram within a required period (for example, a period in which the operation mode of the storage element is not much different, a period in which the calculation error of the electric quantity does not exceed the allowable range, etc.) can be generated. In the above, as a partial charge and discharge curve diagram, an Ah-OCV characteristic based on time series data of electric quantity and voltage is illustrated. Alternatively, the partial charge and discharge curve diagram may also be an SOC-OCV characteristic based on time series data of SOC and voltage.

[0098] The estimation unit 514 estimates the overall discharge characteristics of the storage element based on the positive electrode single-pole characteristics and the negative electrode single-pole characteristics of the storage element. The positive electrode single-pole characteristics are characteristics represented by the discharge curve of the positive electrode (for example, the counter electrode is lithium). The discharge curve of the positive electrode can be a curve obtained by plotting the discharge capacity and the potential corresponding to the capacity with the horizontal axis being the discharge capacity and the vertical axis being the potential (see Fig. 9 ). The negative electrode single-pole characteristic is a characteristic represented by the discharge curve of the negative electrode (for example, the counter electrode is lithium). The discharge curve of the negative electrode can be a curve obtained by plotting the discharge capacity and the potential corresponding to the capacity with the horizontal axis as the discharge capacity and the vertical axis as the potential (see Fig. 9 ).

[0099] The difference between the potential of the positive electrode and the potential of the negative electrode becomes the voltage of the storage element. The estimation unit 514 can estimate the overall discharge curve by calculating the difference between the potential of the positive electrode discharge curve and the potential of the negative electrode discharge curve corresponding to each charge (capacity). The overall discharge characteristic can also be a characteristic represented by the overall discharge curve.

[0100] When estimating the overall discharge characteristics, the estimating unit 514 receives the internal state quantity parameter from the adjusting unit 515. The estimating unit 514 estimates the overall discharge characteristics using the positive electrode single-pole characteristics and the negative electrode single-pole characteristics corresponding to the received internal state quantity parameters.

[0101] The adjustment unit 515 adjusts the internal state quantity parameters so that the overall discharge characteristics estimated by the estimation unit 514 are close to the partial charge and discharge curve graph generated by the generation unit 513. The internal state quantity parameters adjusted by the adjustment unit 515 are output to the estimation unit 514 again, and the estimation of the overall discharge characteristics is repeated. The overall discharge characteristics that conform to the actual situation can be estimated by the optimized internal state quantity parameters. The adjustment unit 515 can be a part of the estimation unit 514.

[0102] Hereinafter, a method of adjusting the internal state quantity parameters and estimating the overall discharge characteristics will be described in detail.

[0103] Fig. 9 This is a diagram for explaining the internal state quantity parameters. Fig. 9 The horizontal axis of the graph shown is SOC (%), the left vertical axis is voltage or potential (V), and the right vertical axis is potential (V). Fig. 9 The positive electrode discharge curve P, the negative electrode discharge curve N, and the overall discharge curve Q are illustrated in FIG.

[0104] exist Fig. 9 In the figure, two positive electrode discharge curves P1 and P2 are shown. For example, the positive electrode effectiveness of the positive electrode discharge curve P1 is 1, and the positive electrode effectiveness of the positive electrode discharge curve P2 corresponds to a value smaller than 1. The positive electrode effectiveness (utilization rate) is an example of an internal state quantity parameter, and is an indicator of the usable amount of active material at the positive electrode. When the positive electrode effectiveness is 1, the storage element is the same as a new product, and as the degradation progresses, the positive electrode effectiveness decreases. As the positive electrode effectiveness decreases, the positive electrode discharge curve changes in a manner that decreases along the horizontal axis.

[0105] In addition, Fig. 9 In the figure, two negative electrode discharge curves N1 and N2 are shown. For example, the charge retention (deviation from 0Ah to the negative side) of the negative electrode discharge curve N1 is about 10Ah (about 15% in terms of SOC), and the charge retention of the negative electrode discharge curve N2 corresponds to a value greater than 10Ah. The charge retention is an example of an internal state quantity parameter and is an indicator of the growth of the SEI (Solid Electrolyte Interphase) film. As the charge retention increases, the negative electrode discharge curve changes in a manner that moves parallel to the left side (negative side) in the horizontal axis direction. The charge retention can also be represented by the discharge start position of the negative electrode (the relative position of the negative electrode).

[0106] Fig. 9 The overall discharge curve Q1 shown shows the overall discharge characteristics (SOC-V characteristics) obtained from the positive electrode discharge curve P1 and the negative electrode discharge curve N1, and the overall discharge curve Q2 shows the overall discharge characteristics (SOC-V characteristics) obtained from the positive electrode discharge curve P2 and the negative electrode discharge curve N2. Fig. 9 As shown, the overall discharge curve Q also changes in accordance with the changes in the positive electrode discharge curve P and the negative electrode discharge curve N. The discharge capacity can be calculated by subtracting the charge (capacity) corresponding to the upper limit voltage from the charge (capacity) corresponding to the lower limit voltage of the overall discharge characteristic. Fig. 9 In the figure, the horizontal axis is represented as SOC, but the horizontal axis can also be capacity.

[0107] The internal state quantity parameter may also include the discharge reserve or the discharge start position of the positive electrode (the relative position of the positive electrode) instead of or in addition to the above internal state quantity parameter. The discharge reserve and the discharge start position of the positive electrode are indicators of oxidative decomposition of the electrolyte.

[0108] As described above, the overall discharge characteristic depends on the internal state quantity parameter. The estimation device 50 adjusts the internal state quantity parameter so that the overall discharge characteristic approaches the partial charge and discharge curve. The estimation device 50 uses the information representing the correspondence between the discharge capacity of the storage element and the internal state quantity parameter stored in the storage unit 52 to adjust the internal state quantity parameter.

[0109] Fig.10 This is a diagram showing an example of the correspondence relationship between the discharge capacity of the power storage element and the internal state quantity parameter. Fig.10 The horizontal axis of the graph shown is the discharge capacity (Ah), the left vertical axis is the positive electrode effectiveness (unitless), and the right vertical axis is the charge retention (Ah). Fig.10 In the graph, the black triangle marks represent the positive electrode effectiveness, and the solid circle marks represent the charge retention. The internal state quantity parameters depend on the discharge capacity. For example, Fig.10 As shown in FIG. 1 , the value of the positive electrode effectiveness increases as the capacity value increases. The value of the charge retention amount decreases as the capacity value increases. By using such a correspondence, the value of each internal state quantity parameter corresponding to a certain capacity value can be determined. Fig.10 The graph of the correspondence relationship shown is only an example and is not limited to this example. The value of the internal state quantity parameter corresponding to the discharge capacity is not limited to one, and may be two or more. The correspondence relationship only needs to include information that can limit the value of the internal state quantity parameter corresponding to the discharge capacity.

[0110] The estimation device 50 obtains continuous discharge characteristics with respect to capacity degradation as learning data based on actual measurement data of a battery test, and analyzes the obtained discharge characteristics to obtain a correspondence between the discharge capacity (electricity) and the internal state quantity parameter. The estimation device 50 stores the obtained correspondence in the storage unit 52 in a data form such as a function expression or a correspondence table.

[0111] The above correspondence may be set in consideration of the state of the storage element. For example, a plurality of correspondence tables may be prepared according to the use history and type of the storage element. The estimation device 50 determines the state of the use history and type of the storage element based on the initial information and operation data of the storage element, and determines the internal state quantity parameter using the correspondence table corresponding to the determined state of the storage element.

[0112] Fig.11 This is a diagram for explaining a method of estimating overall discharge characteristics. Fig.11 The horizontal axis of the graph shown is charge (Ah) and the vertical axis is voltage or potential (V). Fig.11 In A, the overall discharge curve Qx, the partial charge and discharge curve S, the positive electrode discharge curve Px, and the negative electrode discharge curve Nx are illustrated.

[0113] The estimation device 50 sets an arbitrary capacity value, and based on the correspondence between the discharge capacity and the internal state quantity parameter, determines the value of the internal state quantity parameter corresponding to the set capacity value according to each internal state quantity parameter. Based on the determined values ​​of each internal state quantity parameter, the estimation device 50 generates a positive electrode discharge curve Px and a negative electrode discharge curve Nx corresponding to the value of each internal state quantity parameter. The estimation device 50 generates an overall discharge curve Qx based on the generated positive electrode discharge curve Px and negative electrode discharge curve Nx.

[0114] The estimation device 50 adjusts the capacity value so that, in the section of the overall discharge curve Qx corresponding to the partial charge and discharge curve graph S, the voltage corresponding to a certain electric quantity of the overall discharge curve Qx approaches the voltage corresponding to the electric quantity of the partial charge and discharge curve graph S. The section corresponding to the partial charge and discharge curve graph S may refer to a section including the electric quantity corresponding to the partial charge and discharge curve graph S among the electric quantities in the overall discharge curve Qx.

[0115] As in Fig.11 As shown in enlarged form in FIG. 1B, the estimation device 50 adjusts the capacity value so that the square sum of the voltage difference ΔVi (ΣΔVi) between the voltage of the partial charge and discharge curve S corresponding to a certain amount of electricity in the above interval and the voltage of the overall discharge curve Qx is 2 ) is minimized. The estimation device 50 may also process the voltage corresponding to the total amount of electricity on the partial charge and discharge curve S. That is, the above-mentioned square sum (ΣΔVi) within the interval may also be 2 ) is linear and d is minimized.

[0116] The estimation device 50 obtains the sum of squares (ΣΔVi 2 ) or its linear sum d is minimized, and the overall discharge characteristics generated by the internal state quantity parameters corresponding to the capacity value are taken as the optimal overall discharge characteristics. The above capacity value corresponds to the discharge capacity obtained by the optimal overall discharge characteristics.

[0117] As described above, by utilizing the correspondence relationship between the discharge capacity and the internal state quantity parameter, the value of the internal state quantity parameter can be efficiently extracted in the adjustment process for making the overall discharge characteristic approximate to the partial charge and discharge curve diagram.

[0118] Fig.121 is a flowchart showing an example of a process performed by the estimation device 50 and the diagnostic device 70. The process in the following flowchart is performed by the control unit 51 according to the estimation program 521 stored in the storage unit 52 of the estimation device 50, and is performed by the control unit 71 according to the diagnostic program 721 stored in the storage unit 72 of the diagnostic device 70.

[0119] The control unit 51 of the estimation device 50 acquires the time series data of the current and voltage of the power storage element (step S11 ) and generates a partial charge and discharge graph (step S12 ).

[0120] The control unit 51 determines the state of the use history and type of the storage element based on the initial information of the storage element stored in advance and the acquired operation data (step S13). The control unit 51 obtains the corresponding relationship corresponding to the determined state of the storage element from the multiple corresponding relationships stored in the storage unit 52 (step S14). When there is only one corresponding relationship stored in the storage unit 52, step S13 may be omitted.

[0121] The control unit 51 sets the capacity value (step S15 ), and determines the value of the internal state quantity parameter corresponding to the set capacity value based on the correspondence relationship between the discharge capacity and the internal state quantity parameter acquired in step S14 (step S16 ).

[0122] The control unit 51 estimates the overall discharge characteristics based on the positive electrode single-pole characteristics and the negative electrode single-pole characteristics corresponding to the values ​​of the identified internal state quantity parameters (step S17 ).

[0123] The control unit 51 determines whether the difference between the voltage in the section corresponding to the partial charge and discharge graph of the estimated overall discharge characteristics and the voltage of the partial charge and discharge graph is within an allowable range (step S18 ).

[0124] If it is determined that the difference is not within the allowable range (step S18: No), the control unit 51 returns the process to step S15. The control unit 51 adjusts the discharge capacity value according to a given rule and repeats the process after step S15. As an example, the control unit 51 can adjust the discharge capacity value by adding or subtracting a given value from the initial capacity value.

[0125] If it is determined that the difference is within the allowable range (step S18: Yes), the control unit 51 determines the obtained overall discharge characteristic as the overall discharge characteristic of the storage element (step S19). The control unit 51 sends the estimation result related to the determined overall discharge characteristic to the diagnostic device 70 (step S20).

[0126] The control unit 71 of the diagnostic device 70 receives the estimated result related to the overall discharge characteristic (step S21). The control unit 71 diagnoses the discharge capacity of the storage element based on the received overall discharge characteristic (step S22). The discharge capacity is obtained by subtracting the electric quantity corresponding to the upper limit voltage from the electric quantity corresponding to the lower limit voltage of the overall discharge characteristic. The value of the discharge capacity diagnosed based on the overall discharge characteristic is equivalent to the capacity value (optimal capacity value) adjusted by the processing of steps S15 to S18. The control unit 71 displays the diagnosis result of the discharge capacity on the display unit 74 (step S23), and ends a series of processing.

[0127] In the above, the capacity value is adjusted by successive calculations. Alternatively, the estimation device 50 may set a plurality of capacity values ​​by changing the capacity value at given intervals, and select an overall discharge characteristic that minimizes the voltage difference from a plurality of overall discharge characteristics generated based on the internal state quantity parameters corresponding to the set respective capacity values. The capacity value corresponding to the selected overall discharge characteristic is determined as the optimal capacity value.

[0128] According to this embodiment, the overall discharge characteristics and the discharge capacity can be estimated without stopping the operation of the storage element or operating it in a specific operation mode for capacity diagnosis. In addition, the overall discharge characteristics can be estimated with high accuracy regardless of the type of load on the storage element. By using the correspondence between the discharge capacity and the internal state quantity parameter, the combined value of multiple internal state quantity parameters used to generate the overall discharge characteristics can be efficiently determined.

[0129] (Second embodiment)

[0130] In the second embodiment, when the power storage element is operated, a correspondence relationship between the discharge capacity and the internal state quantity parameter is generated.

[0131] Fig.13 This is a flowchart showing an example of a processing procedure executed by the estimation device 50 according to the second embodiment.

[0132] The control unit 51 of the estimation device 50 executes Fig.12 The same processing as steps S11 to S12 is performed to obtain time series data of current and voltage (step S31 ), and to generate a partial charge and discharge curve graph (step S32 ).

[0133] The control unit 51 generates a correspondence relationship between the discharge capacity and the internal state quantity parameter by analyzing the acquired partial charge and discharge curve diagram (step S33). For example, the control unit 51 analyzes the limited partial charge and discharge curve diagram of the electric quantity region, and plots the discharge capacity and the internal state quantity parameter corresponding to the discharge capacity with the horizontal axis set to the discharge capacity and the vertical axis set to the internal state quantity parameter for the limited discharge capacity (electric quantity). The control unit 51 can obtain a correlation function representing the correspondence relationship between the discharge capacity and the internal state quantity parameter related to the total discharge capacity by obtaining an approximate formula of the obtained plot.

[0134] Afterwards, the control unit 51 executes Fig.12 The processing after step S15 shown in the figure performs the estimation processing of the whole discharge characteristic based on the generated correspondence relationship.

[0135] According to this embodiment, it is not necessary to prepare the correspondence relationship between the discharge capacity and the internal state quantity parameter in advance, and the overall discharge characteristic can be estimated more easily. By generating the correspondence relationship based on the operation data of the storage element, it is possible to generate a correspondence relationship that appropriately reflects the state of the storage element to be estimated.

[0136] The embodiments disclosed herein are illustrative in all aspects and are not restrictive. The technical features described in the embodiments can be combined with each other, and the scope of the present invention is intended to include all changes within the scope of the patent claims and the scope equivalent to the scope of the patent claims.

[0137] The order shown in each embodiment is not restrictive, and each process may be executed in a different order within the scope of no contradiction, and multiple processes may be executed in parallel. The processing subject of each process is not restrictive, and the processing of each device may be executed by other devices within the scope of no contradiction.

[0138] The matters recorded in each embodiment can be combined with each other. In addition, the independent technical solutions and dependent technical solutions recorded in the scope of the patent claim can be combined with each other in all combinations regardless of the reference form. Furthermore, in the scope of the patent claim, a form of recording a technical solution that cites two or more other technical solutions (multiple technical solution form) is used, but it is not limited to this. It can also be recorded in the form of recording multiple technical solutions that cite at least one multiple technical solution (multiple citing multiple technical solutions).

[0139] Explanation of symbols

[0140] 100 Power Generation System

[0141] 10. Communication equipment

[0142] 11. Control Unit

[0143] 12 Storage

[0144] 13 1st Communications Department

[0145] 14 2nd Communications Department

[0146] 20 Server Devices

[0147] 30 Domain Management Device

[0148] 40 Storage unit

[0149] 41 Group

[0150] 42 Storage Module

[0151] 43 Measurement substrate

[0152] 44 Battery Management Device

[0153] 50 Prediction device

[0154] 51 Control Department

[0155] 52 Storage

[0156] 53 Ministry of Communications

[0157] 511 Acquisition Department

[0158] 512 Computing Department

[0159] 513 Generation Department

[0160] 514 Presumption

[0161] 515 Adjustment Department

[0162] 521 Presumption Procedure

[0163] 5A Recording medium

[0164] 70 Diagnostic Devices

[0165] 71 Control Department

[0166] 72 Storage

[0167] 73 Ministry of Communications

[0168] 721 diagnostic procedure.

Claims

1. An estimation device comprising: an acquisition unit that acquires time series data of current and voltage of the power storage element; a calculation unit that calculates the time series data of the electric quantity or the SOC based on the time series data of the current acquired by the acquisition unit; a generating unit that generates a partial charge and discharge curve graph of the power storage element based on the time series data of the current acquired by the acquiring unit and the time series data of the electric quantity or the SOC calculated by the calculating unit; and An estimating unit estimates overall discharge characteristics of the storage element based on a parameter indicating an internal state quantity of the storage element, the parameter being adjusted so that a graph of a predetermined interval in the overall discharge characteristics of the storage element approaches the partial charge and discharge graph.

2. The estimation device according to claim 1, wherein: The estimation device includes an adjustment unit that adjusts the parameter based on a correspondence relationship between the capacity of the power storage element and the parameter.

3. The estimation device according to claim 2, wherein: The adjustment unit adjusts the parameter so that a graph of a predetermined section in the overall discharge characteristic related to the capacity corresponding to the parameter approaches the partial charge and discharge graph.

4. The estimation device according to claim 2 or 3, wherein: The corresponding relationship is set to be multiple according to the state of the storage element. The adjustment unit selects a correspondence relationship used for determining the parameter according to a state of the power storage element.

5. The estimation device according to claim 2 or 3, wherein: The adjustment unit generates the correspondence relationship based on the partial charge and discharge graph.

6. The estimation device according to claim 1 or 2, wherein: The estimating unit estimates the overall discharge characteristics of the energy storage element based on the parameter, the positive electrode single pole characteristic, and the negative electrode single pole characteristic of the energy storage element.

7. The estimation device according to claim 1 or 2, wherein: The parameters include the positive electrode effectiveness and the charge retention of the negative electrode.

8. A diagnostic device comprising: The processing unit diagnoses the capacity of the storage element based on the overall discharge characteristic estimated by the estimation device according to claim 1 or 2.

9. A method for inferring, wherein the following processing is performed by a computer: Acquire time series data of current and voltage of the storage element; Calculate the time series data of power or SOC based on the acquired time series data of current; generating a partial charge and discharge curve graph of the power storage element based on the acquired time series data of the current and the calculated time series data of the power quantity or SOC; The overall discharge characteristic of the storage element is estimated based on a parameter indicating an internal state quantity of the storage element, the parameter being adjusted so that a graph of a given section of the overall discharge characteristic of the storage element approaches the partial charge and discharge graph.

10. A presumption program for causing a computer to execute the following processing: Acquire time series data of current and voltage of the storage element; Calculate the time series data of power or SOC based on the acquired time series data of current; generating a partial charge and discharge curve graph of the power storage element based on the acquired time series data of the current and the calculated time series data of the power quantity or SOC; The overall discharge characteristic of the storage element is estimated based on a parameter indicating an internal state quantity of the storage element, the parameter being adjusted so that a graph of a given section of the overall discharge characteristic of the storage element approaches the partial charge and discharge graph.

11. A diagnostic method, comprising: performing the following processing by a computer: Acquire time series data of current and voltage of the storage element; Calculate the time series data of power or SOC based on the acquired time series data of current; Generate a partial charge and discharge curve graph of the storage element based on the acquired time series data of the current and the calculated time series data of the quantity of electricity or SOC; estimating overall discharge characteristics of the storage element based on a parameter representing an internal state quantity of the storage element, the parameter being adjusted so that a graph of a given interval in the overall discharge characteristics of the storage element approaches the partial charge and discharge graph; The capacity of the power storage element is diagnosed based on the estimated overall discharge characteristics.

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