WO2024111395A1 - Battery management system, battery management method, and battery management program - Google Patents
Battery management system, battery management method, and battery management program Download PDFInfo
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- WO2024111395A1 WO2024111395A1 PCT/JP2023/039933 JP2023039933W WO2024111395A1 WO 2024111395 A1 WO2024111395 A1 WO 2024111395A1 JP 2023039933 W JP2023039933 W JP 2023039933W WO 2024111395 A1 WO2024111395 A1 WO 2024111395A1
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- 238000007726 management method Methods 0.000 title claims description 53
- 238000004364 calculation method Methods 0.000 claims abstract description 80
- 230000015556 catabolic process Effects 0.000 claims description 16
- 238000006731 degradation reaction Methods 0.000 claims description 16
- 238000007619 statistical method Methods 0.000 claims description 11
- 230000007423 decrease Effects 0.000 claims description 6
- 230000006866 deterioration Effects 0.000 abstract description 21
- 238000000034 method Methods 0.000 description 18
- 238000010586 diagram Methods 0.000 description 13
- 230000008569 process Effects 0.000 description 12
- 238000012545 processing Methods 0.000 description 11
- 238000004891 communication Methods 0.000 description 9
- 230000008859 change Effects 0.000 description 6
- 238000007599 discharging Methods 0.000 description 5
- 230000006870 function Effects 0.000 description 4
- 230000001186 cumulative effect Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000491 multivariate analysis Methods 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/385—Arrangements for measuring battery or accumulator variables
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/389—Measuring internal impedance, internal conductance or related variables
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/392—Determining battery ageing or deterioration, e.g. state of health
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/44—Methods for charging or discharging
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- One aspect of the present disclosure relates to a battery management system, a battery management method, and a battery management program.
- Patent Document 1 describes an automatic battery life determination device for an electrically powered vehicle.
- This automatic battery life determination device has a voltage/current detection means for detecting the battery's terminal voltage and output current, a resistance detection means for calculating the battery's internal resistance from the detected changes in terminal current and output voltage, a limit drive power calculation means for calculating the battery output at the minimum drive voltage value of the motor based on the terminal voltage change data and output current change data, and an output means for comparing the calculated internal resistance with a reference value representing the maximum internal resistance capable of ensuring battery performance and for comparing the calculated output with a reference value representing the minimum output capable of ensuring the performance of the electrically powered vehicle, and for determining and notifying that the battery has reached the end of its life or is nearing the end of its life.
- a battery management system includes an acquisition unit that acquires reference data indicating the state of a storage battery in a reference period and target data indicating the state of the storage battery in a target period following the reference period, a calculation unit that calculates a characteristic value related to the discharge of the storage battery in the reference period as a reference characteristic value based on the reference data and a minimum drive voltage of an electric device that uses power supplied from the storage battery, and calculates a characteristic value related to the discharge of the storage battery in the target period as a target characteristic value based on the target data and the minimum drive voltage, and an estimation unit that estimates a degradation state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value.
- a battery management method is executed by a battery management system having at least one processor.
- This battery management method includes the steps of acquiring reference data indicating the state of the storage battery in a reference period and target data indicating the state of the storage battery in a target period after the reference period, calculating a characteristic value related to the discharge of the storage battery in the reference period as a reference characteristic value based on the reference data and a minimum drive voltage of an electric device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery in the target period as a target characteristic value based on the target data and the minimum drive voltage, and estimating a deterioration state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value.
- a battery management program causes a computer to execute the steps of acquiring reference data indicating the state of a storage battery during a reference period and target data indicating the state of the storage battery during a target period following the reference period, calculating a characteristic value relating to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and the minimum operating voltage of an electric device that uses power supplied from the storage battery, and calculating a characteristic value relating to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum operating voltage, and estimating a deterioration state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value.
- the degraded state of the storage battery is estimated from the relationship between a reference characteristic value calculated based on the reference data and the minimum driving voltage and a target characteristic value calculated based on the target data and the minimum driving voltage.
- the minimum driving voltage which is a parameter of the electrically-driven device to which power is supplied from the storage battery, it is possible to calculate a reference characteristic value and a target characteristic value that are in line with the actual use of the storage battery. Therefore, the degraded state of the storage battery can be accurately estimated based on the relationship between these two characteristic values.
- the deterioration state of a storage battery can be accurately estimated.
- FIG. 2 is a diagram illustrating an example of a functional configuration of a battery management system.
- FIG. 2 is a diagram illustrating an example of a hardware configuration of a computer that constitutes a battery management system.
- 4 is a flowchart showing an example of a process performed by the battery management system.
- FIG. 11 is a diagram illustrating an example of time-series data of SOC.
- FIG. 13 is a diagram showing another example of time-series data of SOC.
- FIG. 1 is a diagram showing an example of a graph relating to OCV-SOC characteristics.
- FIG. 13 is a diagram showing an example of a graph relating to DCR-SOC characteristics.
- FIG. 13 is a diagram showing an example of a graph relating to a reference characteristic value and a target characteristic value.
- the battery management system 1 is a computer system that estimates the degradation state of a storage battery.
- the degradation state indicates the degree to which the performance of the storage battery has deteriorated from a new state at the time of manufacture.
- Examples of the types of storage battery include, but are not limited to, a lead-acid battery and a lithium-ion battery.
- the storage battery may be a battery pack composed of a plurality of single cells of the same type.
- the battery management system 1 estimates the degradation state of a storage battery that supplies power to an electrically-driven device. In other words, it can be said that the battery management system 1 estimates the degradation state of a storage battery mounted on or connected to the electrically-driven device.
- An electrically-driven device is a device that operates using all or part of the electric energy stored in a storage battery as its motive power.
- the electrically-driven device may be, for example, an electric vehicle or a robot.
- the electrically-driven vehicle may be a vehicle for carrying people or a vehicle for moving luggage.
- the electrically-driven vehicle may be an aerial work vehicle having a function of moving people vertically, or a loading vehicle having a function of moving luggage vertically.
- the loading vehicle may be, for example, a forklift or an automated guided vehicle (AGV).
- the battery management system 1 may estimate the degradation state of a storage battery mounted on a forklift.
- FIG. 1 is a diagram showing the functional configuration of a battery management system 1 according to an example.
- the battery management system 1 estimates the degradation state of a storage battery mounted on or connected to an electrically-driven device 2.
- the battery management system 1 includes a server 10.
- the server 10 can access a database 20 that stores storage battery data indicating the state of the storage battery mounted on or connected to the electrically-driven device 2 via a communication network.
- the database 20 stores storage battery data for each of at least one electrically-driven device 2.
- the database 20 may be a component of the battery management system 1, or may be provided in a computer system separate from the battery management system 1.
- the communication network used for the battery management system 1 is, for example, composed of at least one of the Internet and an intranet.
- Each electric device 2 provides storage battery data to the database 20.
- the electric device 2 includes a battery management unit (BMU) 3 that monitors or controls the storage battery.
- the BMU 3 repeatedly measures the state of the storage battery at a given time interval and generates storage battery data indicating the state.
- the BMU 3 then transmits the storage battery data to the database 20 via a communication network at a given timing.
- the BMU 3 may be provided outside the electric device 2.
- the storage battery data is time-series data indicating the state of the storage battery.
- each record of the storage battery data includes a measurement date and time and at least one physical quantity indicating the state of the storage battery. Examples of the physical quantity include, but are not limited to, a measured voltage, a measured current, and a measured temperature.
- each record of the storage battery includes a measured current
- the measured current when the storage battery is charging is recorded as a positive value
- the measured current when the storage battery is discharging is recorded as a negative value.
- the storage battery data indicates a physical quantity measured, for example, every 100 milliseconds.
- the storage battery data is associated with at least one of a storage battery ID and an electric device ID.
- the storage battery ID is an identifier that uniquely identifies the storage battery.
- the electric device ID is an identifier that uniquely identifies the electric device 2.
- the server 10 is a computer that estimates the deterioration state of the storage battery based on the storage battery data.
- the server 10 has the following functional modules: an acquisition unit 11, a calculation unit 12, an estimation unit 13, and an output unit 14.
- the acquisition unit 11 is a functional module that acquires storage battery data from the database 20.
- the calculation unit 12 is a functional module that calculates characteristic values related to the discharge of the storage battery using the acquired storage battery data.
- the estimation unit 13 is a functional module that estimates the deterioration state of the storage battery based on the calculated characteristic values.
- the output unit 14 is a functional module that outputs processing results including the estimated deterioration state.
- FIG. 2 is a diagram showing an example of a general hardware configuration of a computer 100 constituting the server 10.
- the computer 100 comprises a processor (e.g., a CPU) 101 that executes an operating system, application programs, etc., a main memory unit 102 consisting of ROM and RAM, an auxiliary memory unit 103 consisting of a storage device such as a hard disk or flash memory, a communication control unit 104 consisting of a network card or wireless communication module, input devices 105 such as a keyboard and mouse, and an output device 106 such as a monitor.
- a processor e.g., a CPU
- main memory unit 102 consisting of ROM and RAM
- an auxiliary memory unit 103 consisting of a storage device such as a hard disk or flash memory
- a communication control unit 104 consisting of a network card or wireless communication module
- input devices 105 such as a keyboard and mouse
- an output device 106 such as a monitor.
- Each functional module of server 10 is realized by loading a predetermined program onto processor 101 or main memory unit 102 and having processor 101 execute the program.
- Processor 101 operates communication control unit 104, input device 105, or output device 106 in accordance with the program, and reads and writes data in main memory unit 102 or auxiliary memory unit 103. Data or databases required for processing are stored in main memory unit 102 or auxiliary memory unit 103.
- the server 10 is composed of at least one computer. When multiple computers are used, a single server 10 is logically constructed by connecting these computers via a communication network such as the Internet or an intranet.
- the battery management program for causing a computer or computer system to function as the battery management system 1 or server 10 includes program code for causing the computer or computer system to function as an acquisition unit 11, a calculation unit 12, an estimation unit 13, and an output unit 14.
- This battery management program may be provided after being non-temporarily recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory. Alternatively, the battery management program may be provided via a communications network as a data signal superimposed on a carrier wave.
- the provided battery management program is stored in, for example, the auxiliary memory unit 103.
- the processor 101 reads out the battery management program from the auxiliary memory unit 103 and executes it to realize each of the above-mentioned functional modules.
- the calculation unit 12 calculates characteristic values related to the discharge of the storage battery.
- the calculation unit 12 calculates characteristic values for each of a reference period and a target period.
- the characteristic values in the reference period are also referred to as “reference characteristic values”
- the characteristic values in the target period are also referred to as “target characteristic values.”
- the calculation unit 12 calculates the discharge time required for the closed circuit voltage (CCV) to reach the minimum drive voltage V min from the voltage at full charge as the characteristic value.
- the discharge time required for the closed circuit voltage (CCV) to reach the minimum drive voltage V min from the voltage at full charge is simply referred to as the "discharge time”.
- the calculation unit 12 may calculate the discharge time when the electric device 2 performs constant power discharge with the maximum discharge power P max as the characteristic value.
- the maximum discharge power P max indicates the power required to operate the electric device 2 at the maximum output.
- the minimum drive voltage V min indicates the minimum voltage required to output the maximum discharge power P max .
- the maximum discharge power P max and the minimum drive voltage V min are values set for each electric device 2, and are recorded in the database 20 in association with at least one of the storage battery ID and the electric device ID, for example.
- the fully charged state refers to the point in time when sufficient electricity is stored in the storage battery, for example, when the SOC (State Of Charge) indicating the charge state of the storage battery is 100% or more.
- the calculation unit 12 uses an OCV-SOC characteristic indicating the relationship between the SOC and an open circuit voltage (OCV) and a DCR-SOC characteristic indicating the relationship between the SOC and a direct current resistance (DCR), in addition to the maximum discharge power P max and the minimum drive voltage V min .
- OCV open circuit voltage
- DCR direct current resistance
- the calculation unit 12 performs calculations based on an equivalent circuit of the storage battery.
- the equivalent circuit includes a power source whose voltage changes in proportion to the SOC, and an internal resistance whose resistance value changes in proportion to the SOC.
- the calculations based on the equivalent circuit include an equation showing the OCV-SOC characteristics and an equation showing the DCR-SOC characteristics.
- the OCV-SOC characteristic may be expressed by a linear equation (1) or a quadratic equation (2).
- OCV a OCV + b OCV ⁇ SOC ...
- OCV a OCV + b OCV ⁇ SOC + c OCV ⁇ SOC 2 ...
- a OCV and b OCV in the formula (1) are first-order approximation constants
- a OCV , b OCV , and c OCV in the formula (2) are second-order approximation constants.
- the DCR-SOC characteristic may be expressed by the linear equation (3) or the quadratic equation (4).
- DCR a DCR + b DCR ⁇ SOC ...
- DCR a DCR + b DCR ⁇ SOC + c DCR ⁇ SOC 2 ... (4) It can be said that aDCR and bDCR in equation (3) are first-order approximation constants, and aDCR , bDCR , and cDCR in equation (4) are second-order approximation constants.
- FIG. 1 is a flowchart showing an example of processing by the battery management system.
- Figures 4 and 5 are diagrams showing examples of time-series data of SOC.
- Figure 6 is a diagram showing an example of a graph relating to OCV-SOC characteristics.
- Figure 7 is a diagram showing an example of a graph relating to DCR-SOC characteristics.
- Figure 8 is a diagram showing an example of a graph relating to a reference characteristic value and a target characteristic value.
- the acquisition unit 11 acquires data identification information.
- the data identification information is information used to read out storage battery data from the database 20.
- the data identification information includes at least one of a storage battery ID and an electric device ID, a maximum discharge power Pmax , a minimum driving voltage Vmin , a reference period, and a target period.
- the reference period may correspond to a time when the storage battery is new
- the target period may correspond to a past time including the current time.
- the reference period and the target period are set by a predetermined time width.
- the time width may be a period during which multiple charging and discharging are expected to be performed, and may be set over multiple days, such as three days.
- the acquisition unit 11 may accept data identification information input by a user of the battery management system 1, or may automatically set the data identification information based on a given rule.
- step S2 the acquisition unit 11 acquires storage battery data corresponding to the reference period as reference data.
- the acquisition unit 11 reads from the database 20 a group of records of storage batteries that correspond to at least one of the storage battery ID and the electric device ID and the reference period.
- step S3 the calculation unit 12 calculates a reference characteristic value based on the reference data acquired in step S2 and the minimum drive voltage Vmin .
- the calculation unit 12 calculates moving averages of the measured voltage and measured current for each of a number of intervals set along the time axis. For example, if the time interval between records is 100 milliseconds, the calculation unit 12 sets the interval to 10 seconds and calculates the average value of 100 physical quantities within that interval every 10 seconds.
- the calculation unit 12 calculates the SOC(k) for each interval k for which the moving average has been obtained, using equation (5).
- SOC(k) 1 ⁇ I(k)/ ⁇ /W bat ... (5)
- W bat indicates the rated capacity of the storage battery
- I(k) indicates the measured current in section k.
- ⁇ I(k)/ ⁇ indicates the consumed capacity of the storage battery up to section k.
- the measured current when the storage battery is in a charging state is recorded as a positive value
- the measured current when the storage battery is in a discharging state is recorded as a negative value. Therefore, ⁇ I(k)/ ⁇ can also be said to be the integrated capacity value of the storage battery up to section k.
- the calculation unit 12 calculates the elapsed time ET for each section k based on each calculated SOC(k).
- the elapsed time ET indicates the time elapsed since the most recent SOC was 100%.
- each record of the time series data obtained by the calculation unit 12 includes the moving average of the measured current, the moving average of the measured voltage, the corresponding SOC, and the corresponding elapsed time ET.
- the calculation unit 12 selects, from the obtained time series data, the time series data of the valid section used to calculate the characteristic value as valid time series data.
- the calculation unit 12 excludes the time series data of the invalid section that may be a cause of error in estimating the degradation state as invalid time series data, and selects the remaining time series data of the valid section as valid time series data.
- the invalid section may include a time period from when the storage battery is fully charged to when a predetermined time Ta has elapsed.
- this time period is also referred to as a first invalid section.
- the predetermined time Ta may be, for example, one hour.
- the invalid section may include a time section from the point at which charging of a storage battery whose charging time is less than the threshold Tb is completed until the time equivalent to the charging time has elapsed.
- this time section is also referred to as a second invalid section.
- the threshold Tb may be, for example, one hour.
- the invalid section may include a time period from the end of charging that starts when the SOC is equal to or greater than the threshold value Ca% and ends when the SOC is less than 100% until the next time the storage battery is fully charged.
- this time period is also referred to as the third invalid section.
- the threshold value Ca may be, for example, 90%.
- the horizontal axis of the graph shown in FIG. 4 indicates time t, and the vertical axis indicates SOC (%).
- the threshold value Ca is 90%.
- charging begins with an SOC of 90% or more, and at time t2, charging ends with an SOC of less than 100%. Thereafter, at time t3, the storage battery is fully charged.
- the calculation unit 12 identifies the time period from time t2 to time t3 as the third invalid section.
- the invalid section may include a time period from the end of charging that starts when the SOC is equal to or greater than a threshold value Ca%, when the SOC has increased by equal to or greater than Ci%, and when the SOC is less than 100%, until the next time the storage battery is fully charged.
- the threshold value Ci may be, for example, 3%.
- the invalid section may include a time period from when the cumulative decrease in SOC reaches 100% without the SOC exceeding the threshold Cb% since the previous full charge to when the storage battery is next fully charged.
- the cumulative decrease in SOC refers to the integrated value of the SOC consumed, regardless of whether the storage battery is charged during discharging.
- this time period is also referred to as the fourth invalid section.
- the threshold Cb may be, for example, 90%.
- the horizontal axis of the graph shown in FIG. 5 indicates time t, and the vertical axis indicates SOC (%).
- the threshold Cb is 90%.
- the previous full charge is completed at time t4, and the next full charge is completed at time t5.
- the storage battery is charged several times between time t4 and time t5, but the SOC does not exceed 90% during this time period.
- the cumulative decrease in SOC of the storage battery that was fully charged at time t4 reaches 100%.
- the calculation unit 12 identifies the time period from time t6 to time t5 as the fourth invalid section.
- the calculation unit 12 excludes the time series data in at least one of the first to fourth invalid intervals as invalid time series data, and selects the time series data in the remaining valid intervals as valid time series data.
- the calculation unit 12 calculates the OCR-SOC characteristic and the DCR-SOC characteristic based on the effective time series data by a statistical method. For example, the calculation unit 12 calculates the OCR-SOC characteristic shown in formula (1) and the DCR-SOC characteristic shown in formula (4). As an example, the calculation unit 12 may use the Marquardt method, which is a nonlinear least square method, as the statistical method.
- the calculation unit 12 calculates the OCV-SOC characteristic and the DCR-SOC characteristic by using the Marquardt method to calculate the first-order approximation constants a OCV and b OCV and the second-order approximation constants a DCR , b DCR , and c DCR that minimize the mean square error between the measured voltage MV and the theoretical voltage CV.
- the theoretical voltage CV in the section k is obtained by formula (6).
- Formula (6) can be said to represent the IV characteristic of the storage battery based on the equivalent circuit of the storage battery, and can also be said to be a calculation formula for the theoretical voltage.
- the calculation unit 12 may use multivariate analysis as a statistical method.
- the calculation unit 12 may calculate the first-order approximation constants aOCV and bOCV and the second-order approximation constants aDCR , bDCR , and cDCR based on the formula (6).
- the calculation unit 12 calculates the IV characteristics so as to minimize the mean square error between the measured voltage MV and the theoretical voltage CV using a statistical method such as the Marquardt method, multivariate analysis, etc.
- the calculation unit 12 calculates the first-order approximation constants aOCV and bOCV and the second-order approximation constants aDCR , bDCR , and cDCR based on the IV characteristics, thereby calculating the OCV-SOC characteristics and the DCR-SOC characteristics.
- the calculation unit 12 calculates the OCV and DCR at each time point in the valid time series data based on the calculated OCV-SOC characteristic and DCR-SOC characteristic.
- the calculation unit 12 calculates the corresponding OCV and DCR by substituting the SOC at each time point into the OCV-SOC characteristic shown in formula (1) and the DCR-SOC characteristic shown in formula (4).
- the calculation unit 12 calculates the CCV at each time point in the valid time-series data by solving the equation (7) showing the relationship between the OCV and DCR, the maximum discharge power Pmax , and the CCV. That is, the calculation unit 12 calculates the corresponding CCV based on the OCV and DCR at each time point and the maximum discharge power Pmax using the equation (8).
- CCV OCV- Pmax /CCV ⁇ DCR (7)
- CCV (OCV + sqrt (OCV 2 - 4 ⁇ P max ⁇ DCR) / 2 ... (8)
- each record of the valid time series data includes a moving average of the measured current, a moving average of the measured voltage, a corresponding SOC, a corresponding elapsed time ET, and a corresponding OCV, DCR, and CCV.
- the calculation unit 12 calculates the discharge time in the reference period as a reference characteristic value based on the CCV at each time point calculated by formula (8) and the corresponding elapsed time ET.
- the calculation unit 12 may obtain the elapsed time ET at the time point when the CCV reaches the minimum drive voltage V min as the discharge time.
- the elapsed time is represented as ET Vmin .
- the calculation unit 12 may calculate the statistical value of multiple elapsed times ET Vmin as the discharge time.
- the statistical value may be, for example, an average value or a median value.
- the calculation unit 12 may calculate a regression equation indicating the relationship between the CCV and the elapsed time ET based on the pair of the CCV and the elapsed time ET at each time point, and apply the minimum drive voltage V min to the regression equation to calculate the discharge time.
- the CCV calculated by the formula (8) is based on the OCV-SOC characteristic and the DCR-SOC characteristic in the reference period. Therefore, it can be said that the calculation unit 12 calculates the reference characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic in the reference period in addition to the minimum drive voltage Vmin .
- step S4 the acquisition unit 11 acquires storage battery data corresponding to the target period as target data.
- the acquisition unit 11 reads out a group of records of storage battery data corresponding to at least one of the storage battery ID and the electric device ID and the target period from the database 20.
- step S5 the calculation unit 12 calculates the target characteristic value based on the target data acquired in step S4 and the minimum driving voltage Vmin .
- the calculation unit 12 calculates the target characteristic value in the same manner as the reference characteristic value. That is, the calculation unit 12 calculates the moving average of the measured voltage and the measured current for each predetermined interval. Then, the calculation unit 12 calculates the SOC for each interval. Then, the calculation unit 12 obtains time series data for the moving average of the measured current, the moving average of the measured voltage, the corresponding SOC, and the corresponding elapsed time ET during the target period. Then, the calculation unit 12 selects valid time series data from the obtained time series data.
- the calculation unit 12 calculates the IV characteristic for the target period using a statistical method based on the valid time series data, and calculates the first-order approximation constants a OCV and b OCV and the second-order approximation constants a DCR , b DCR , and c DCR based on the IV characteristic, thereby calculating the OCV-SOC characteristic and the DCR-SOC characteristic.
- the calculation unit 12 calculates the CCV at each time point in the valid time series data based on the OCV and DCR at each time point obtained by the OCV-SOC characteristic and the DCR-SOC characteristic, and the maximum discharge power P max . Then, the calculation unit 12 calculates the discharge time in the target period as the target characteristic value based on the calculated CCV at each time point and the corresponding elapsed time ET. As in the process for the reference period, the calculation unit 12 may calculate the statistical value of a plurality of elapsed times ET Vmin as the discharge time, or may calculate the discharge time by a regression equation. As in the calculation of the reference characteristic value, the calculation unit 12 may calculate the target characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic in the target period in addition to the minimum drive voltage V min .
- step S6 the calculation unit 12 calculates the relationship between the reference characteristic value and the target characteristic value.
- the ratio between the reference characteristic value and the target characteristic value is calculated as the relationship between the reference characteristic value and the target characteristic value.
- the difference between the reference characteristic value and the target characteristic value may be calculated as the relationship between the reference characteristic value and the target characteristic value.
- the relationship between the reference characteristic value and the target characteristic value indicates how the characteristics of the storage battery have changed over time from the reference period to the target period. Therefore, the relationship between the two can be said to represent the SOH (State of Health), which indicates the deterioration state of the storage battery.
- the calculation unit 12 may calculate a ratio relating to the discharge time as the relationship between the reference period and the target characteristic value. In one example, the calculation unit 12 calculates a ratio indicating the relationship between the discharge time in the reference period and the discharge time in the target period as the relationship between the reference characteristic value and the target characteristic value. In the present disclosure, this relationship is also referred to as "SOH-P.”
- step S7 the estimation unit 13 estimates the degraded state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value. In one example, the estimation unit 13 estimates the degraded state of the storage battery based on the ratio between the discharge time in the reference period and the discharge time in the target period. Alternatively, the estimation unit 13 may estimate the degraded state of the storage battery based on the difference between the reference characteristic value and the target characteristic value.
- the output unit 14 outputs the processing result.
- the output unit 14 outputs the deterioration state of the storage battery estimated by the estimation unit 13 as the processing result.
- the output unit 14 outputs the relationship between the reference characteristic value and the target characteristic value calculated by the calculation unit 12 as the processing result in addition to the deterioration state. As described above, the relationship may be the ratio between the reference characteristic value and the target characteristic value, or the difference between the reference characteristic value and the target characteristic value.
- the output unit 14 may output the deterioration state of the storage battery to another functional module in the battery management system 1 for subsequent processing in the battery management system 1.
- the output unit 14 may store the deterioration state of the storage battery in a predetermined storage device such as a memory or a database.
- the output unit 14 may display the deterioration state of the storage battery on a display device.
- the output unit 14 may transmit the deterioration state of the storage battery to another computer system.
- the reference period corresponds to a period during which the storage battery is new
- the target period corresponds to a period during which the storage battery is degraded.
- the calculation unit 12 calculates the OCV-SOC characteristics as shown in Figure 6, and calculates the DCR-SOC characteristics as shown in Figure 7.
- graph 201 shows the OCV-SOC characteristics in the reference period
- graph 202 shows the OCV-SOC characteristics in the target period.
- graph 211 shows the DCR-SOC characteristics in the reference period
- graph 212 shows the DCR-SOC characteristics in the target period.
- FIG. 8 corresponds to FIG. 6 and FIG. 7.
- the horizontal axis indicates time (h), and the vertical axis indicates CCV (V).
- graph 221 indicates the discharge time in the reference period
- graph 222 indicates the discharge time in the target period.
- the ratio of the target characteristic value to the reference characteristic value is represented as SOH-P
- the SOH-P gradually decreases from 1.0 (or 100%) as the storage battery deteriorates.
- the SOH-P is 0.5 (or 50%) or less, there is a high probability that the product life of the storage battery is at the end. In this way, the deterioration state of the storage battery can be estimated based on the value of SOH-P, i.e., the relationship between the reference characteristic value and the target characteristic value.
- the battery management system 1 may repeatedly execute the processes of steps S4 to S6 for each of the multiple target periods while repeatedly using the reference characteristic value calculated once in steps S2 and S3. That is, the calculation unit 12 may calculate the target characteristic value for each of the multiple target periods and calculate the relationship between the reference characteristic value and the target characteristic value. In this case, the calculation unit 12 may weight the calculated relationship for each target period based on a weighting parameter, and then calculate an average value of the relationship for the multiple target periods. This average value can also be said to be a weighted average value.
- the weighting parameter includes at least one of an approximate constant in the OCV-SOC characteristic, an approximate constant in the DCR-SOC characteristic, a total discharge amount in the target period, a time interval with respect to the timing of refilling the storage battery, and a rate of change of the target characteristic value.
- the rate of change of the target characteristic value indicates the rate of change from the target characteristic value in the previous target period.
- the battery management system 1 may estimate the deterioration state of the storage battery based on the weighted average value.
- one target period is regarded as one cycle, and multiple target periods for obtaining one weighted average value are set as n cycles, where n>1.
- a weighted average value of the relationship between the reference characteristic value and the target characteristic value in n cycles is calculated.
- the battery management system 1 may calculate a weighted average value of the relationship between the reference characteristic value and the target characteristic value for each combination while shifting combinations of n consecutive target periods along the time axis, and calculate time series data of a weighted moving average of the relationship.
- the battery management system 1 may estimate the degradation state of the storage battery based on the time series data.
- the estimation unit 13 may determine that the relationship between the reference characteristic value calculated using those characteristics and the target characteristic value is invalid. If the relationship between the reference characteristic value and the target characteristic value is invalid, the estimation unit 13 may not need to estimate the degradation state of the storage battery based on that relationship.
- the estimation unit 13 may estimate that a sudden change has occurred in the characteristics of the storage battery.
- the output unit 14 may output, as a processing result, information indicating that the product life of the storage battery is at the end, based on the estimation.
- the calculation unit 12 may calculate the OCV-SOC characteristics and the DCR-SOC characteristics using a method other than a statistical method. For example, the calculation unit 12 may calculate the OCV-SOC characteristics and the DCR-SOC characteristics using a Kalman filter each time measurement data is obtained.
- a computer or device other than the server 10 may calculate the relationship between the reference characteristic value and the target characteristic value.
- each BMU 3 may calculate the relationship between the reference characteristic value and the target characteristic value for the corresponding storage battery.
- the battery management system may be implemented in the BMU 3.
- the BMU 3 may calculate a moving average of the measured voltage and current, and transmit storage battery data indicating these moving averages to the database 20. In this case, the amount of communication between the BMU 3 and the database 20 can be reduced, and the processing load on the server 10 can be reduced.
- the battery management method executed by at least one processor is not limited to the above examples. For example, some of the steps or processes described above may be omitted, or the steps may be executed in a different order. Also, any two or more of the steps described above may be combined, or some of the steps may be modified or deleted. Alternatively, other steps may be executed in addition to the steps described above.
- the expression "at least one processor executes a first process, executes a second process, ... executes an nth process” or a corresponding expression indicates a concept including a case where the processor executing the n processes from the first process to the nth process changes midway.
- this expression indicates a concept including both a case where all n processes are executed by the same processor and a case where the processor changes among the n processes according to an arbitrary policy.
- a battery management system comprising: ⁇ Item 2> The calculation unit, A discharge time during the reference period during which the closed circuit voltage of the storage battery decreases from a fully charged voltage to the minimum driving voltage is calculated as the reference characteristic value; Calcul
- the battery management system calculates a ratio between the reference characteristic value and the target characteristic value as the relationship.
- the battery management system includes at least a measured voltage and a measured current of the storage battery;
- the calculation unit Based on the reference data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the reference period is calculated by a statistical method, and based on the IV characteristic, the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period are obtained;
- Based on the target data an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the target period is calculated by the statistical method, and the OCV-SOC characteristic and the DCR-SOC characteristic during the target period are obtained based on the IV characteristic. 5.
- a battery management method executed by a battery management system having at least one processor comprising: obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period; calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage; estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
- a battery management method comprising: ⁇ Item 7> obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period; calculating a characteristic value related to the discharge of
- the degraded state of the storage battery is estimated from the relationship between the reference characteristic value calculated based on the reference data and the minimum driving voltage and the target characteristic value calculated based on the target data and the minimum driving voltage.
- the minimum driving voltage which is a parameter of the electrically-driven device to which power is supplied from the storage battery, it is possible to calculate the reference characteristic value and the target characteristic value that are in line with the actual use of the storage battery. Therefore, the degraded state of the storage battery can be accurately estimated based on the relationship between these two characteristic values.
- the reference characteristic value and the target characteristic value can be accurately calculated.
- OCV-SOC characteristics and DCR-SOC characteristics by using statistical methods to obtain the OCV-SOC characteristics and DCR-SOC characteristics, these characteristics can be obtained with high accuracy from the measured values of the storage battery.
- OCV-SOC characteristics and DCR-SOC characteristics By using the accurately obtained OCV-SOC characteristics and DCR-SOC characteristics to calculate the characteristic values, it is expected that the accuracy of both the calculation of the characteristic values and the deterioration state of the storage battery during the reference period and the target period can be improved.
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Abstract
This battery management system comprises: an acquisition unit that acquires reference data indicating the state of a storage battery during a reference period and target data indicating the state of the storage battery in a target period after the reference period; a calculation unit that calculates the characteristic value regarding discharge of the storage battery during the reference period as a reference characteristic value, on the basis of the reference data and a minimum drive voltage of electric equipment that uses power supplied from the storage battery, and calculates the characteristic value related to the discharge of the storage battery during the target period as a target characteristic value on the basis of the target data and the minimum drive voltage; and an estimation unit that estimates a deterioration state of the storage battery on the basis of a relationship between the reference characteristic value and the target characteristic value.
Description
本開示の一側面は、電池管理システム、電池管理方法、および電池管理プログラムに関する。
One aspect of the present disclosure relates to a battery management system, a battery management method, and a battery management program.
特許文献1には、電気駆動車両の電池寿命自動判定装置が記載されている。この電池寿命自動判定装置は、電池の端子電圧と出力電流とを検知する電圧電流検出手段と、検知された端子電流の変化量と出力電圧の変化量とから電池の内部抵抗を算定する抵抗検出手段と、端子電圧の変化データおよび出力電流の変化データに基づいて電動機の最低駆動電圧値における電池の出力を算出する限界駆動電力算出手段と、算定された内部抵抗を電池性能を確保することが可能な最大内部抵抗を表す基準値と比較すると共に算出された出力を電気駆動車両の性能を確保することの出来る最低出力を表す基準値と比較し電池の寿命が到来したことまたは電池の寿命が近いこと判定し報知する出力手段とを有する。
Patent Document 1 describes an automatic battery life determination device for an electrically powered vehicle. This automatic battery life determination device has a voltage/current detection means for detecting the battery's terminal voltage and output current, a resistance detection means for calculating the battery's internal resistance from the detected changes in terminal current and output voltage, a limit drive power calculation means for calculating the battery output at the minimum drive voltage value of the motor based on the terminal voltage change data and output current change data, and an output means for comparing the calculated internal resistance with a reference value representing the maximum internal resistance capable of ensuring battery performance and for comparing the calculated output with a reference value representing the minimum output capable of ensuring the performance of the electrically powered vehicle, and for determining and notifying that the battery has reached the end of its life or is nearing the end of its life.
蓄電池の劣化状態を正確に推定する手法が望まれている。
There is a need for a method to accurately estimate the deterioration state of storage batteries.
本開示の一側面に係る電池管理システムは、基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得する取得部と、基準データと、蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、基準期間における蓄電池の放電に関する特性値を基準特性値として算出し、対象データと最低駆動電圧とに基づいて、対象期間における蓄電池の放電に関する特性値を対象特性値として算出する算出部と、基準特性値と対象特性値との関係に基づいて、蓄電池の劣化状態を推定する推定部とを備える。
A battery management system according to one aspect of the present disclosure includes an acquisition unit that acquires reference data indicating the state of a storage battery in a reference period and target data indicating the state of the storage battery in a target period following the reference period, a calculation unit that calculates a characteristic value related to the discharge of the storage battery in the reference period as a reference characteristic value based on the reference data and a minimum drive voltage of an electric device that uses power supplied from the storage battery, and calculates a characteristic value related to the discharge of the storage battery in the target period as a target characteristic value based on the target data and the minimum drive voltage, and an estimation unit that estimates a degradation state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value.
本開示の一側面に係る電池管理方法は、少なくとも一つのプロセッサを備える電池管理システムにより実行される。この電池管理方法は、基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、基準データと、蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、基準期間における蓄電池の放電に関する特性値を基準特性値として算出し、対象データと最低駆動電圧とに基づいて、対象期間における蓄電池の放電に関する特性値を対象特性値として算出するステップと、基準特性値と対象特性値との関係に基づいて、蓄電池の劣化状態を推定するステップとを含む。
A battery management method according to one aspect of the present disclosure is executed by a battery management system having at least one processor. This battery management method includes the steps of acquiring reference data indicating the state of the storage battery in a reference period and target data indicating the state of the storage battery in a target period after the reference period, calculating a characteristic value related to the discharge of the storage battery in the reference period as a reference characteristic value based on the reference data and a minimum drive voltage of an electric device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery in the target period as a target characteristic value based on the target data and the minimum drive voltage, and estimating a deterioration state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value.
本開示の一側面に係る電池管理プログラムは、基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、基準データと、蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、基準期間における蓄電池の放電に関する特性値を基準特性値として算出し、対象データと最低駆動電圧とに基づいて、対象期間における蓄電池の放電に関する特性値を対象特性値として算出するステップと、基準特性値と対象特性値との関係に基づいて、蓄電池の劣化状態を推定するステップとをコンピュータに実行させる。
A battery management program according to one aspect of the present disclosure causes a computer to execute the steps of acquiring reference data indicating the state of a storage battery during a reference period and target data indicating the state of the storage battery during a target period following the reference period, calculating a characteristic value relating to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and the minimum operating voltage of an electric device that uses power supplied from the storage battery, and calculating a characteristic value relating to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum operating voltage, and estimating a deterioration state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value.
このような側面においては、基準データおよび最低駆動電圧に基づいて算出された基準特性値と対象データおよび最低駆動電圧に基づいて算出された対象特性値との関係から、蓄電池の劣化状態が推定される。蓄電池から電力が供給される電動機器のパラメータである最低駆動電圧を考慮することで、該蓄電池の実使用に即した基準特性値および対象特性値を算出することができる。したがって、これら二つの特性値の関係に基づいて、蓄電池の劣化状態を正確に推定することができる。
In this aspect, the degraded state of the storage battery is estimated from the relationship between a reference characteristic value calculated based on the reference data and the minimum driving voltage and a target characteristic value calculated based on the target data and the minimum driving voltage. By taking into account the minimum driving voltage, which is a parameter of the electrically-driven device to which power is supplied from the storage battery, it is possible to calculate a reference characteristic value and a target characteristic value that are in line with the actual use of the storage battery. Therefore, the degraded state of the storage battery can be accurately estimated based on the relationship between these two characteristic values.
本開示の一側面によれば、蓄電池の劣化状態を正確に推定することができる。
According to one aspect of the present disclosure, the deterioration state of a storage battery can be accurately estimated.
以下、添付図面を参照しながら本開示での実施形態を詳細に説明する。図面の説明において同一または同等の要素には同一の符号を付し、重複する説明を省略する。
Below, an embodiment of the present disclosure will be described in detail with reference to the attached drawings. In the description of the drawings, identical or equivalent elements are given the same reference numerals, and duplicate descriptions will be omitted.
[システムの構成]
電池管理システム1は、蓄電池の劣化状態を推定するコンピュータシステムである。劣化状態は、蓄電池の性能が、製造時の状態である新品の状態から、どの程度劣化しているのかを示す。蓄電池の種類の例として鉛蓄電池およびリチウムイオン電池が挙げられるが、これらに限定されない。蓄電池は同じ種類の複数の単電池によって構成される組電池でもよい。 [System Configuration]
Thebattery management system 1 is a computer system that estimates the degradation state of a storage battery. The degradation state indicates the degree to which the performance of the storage battery has deteriorated from a new state at the time of manufacture. Examples of the types of storage battery include, but are not limited to, a lead-acid battery and a lithium-ion battery. The storage battery may be a battery pack composed of a plurality of single cells of the same type.
電池管理システム1は、蓄電池の劣化状態を推定するコンピュータシステムである。劣化状態は、蓄電池の性能が、製造時の状態である新品の状態から、どの程度劣化しているのかを示す。蓄電池の種類の例として鉛蓄電池およびリチウムイオン電池が挙げられるが、これらに限定されない。蓄電池は同じ種類の複数の単電池によって構成される組電池でもよい。 [System Configuration]
The
一例では、電池管理システム1は、電動機器に対して電力を供給する蓄電池の劣化状態を推定する。すなわち、電池管理システム1は、電動機器に搭載または接続された蓄電池の劣化状態を推定するともいえる。電動機器とは、蓄電池に貯えられた電気エネルギを動力の全てまたは一部として用いて動作する機器をいう。電動機器は、例えば、電動車両であってもよく、ロボットであってもよい。電動車両は、人を乗せるための車両であってもよく、荷物を移動させるための車両であってもよい。電動車両は、人を鉛直方向に移動させる機能を有する高所作業車でもよいし、荷物を鉛直方向に移動させる機能を有する荷役車両であってもよい。荷役車両は、例えばフォークリフトまたは無人搬送車両(AGV)であってもよい。一例では、電池管理システム1は、フォークリフトに搭載された蓄電池の劣化状態を推定してもよい。
In one example, the battery management system 1 estimates the degradation state of a storage battery that supplies power to an electrically-driven device. In other words, it can be said that the battery management system 1 estimates the degradation state of a storage battery mounted on or connected to the electrically-driven device. An electrically-driven device is a device that operates using all or part of the electric energy stored in a storage battery as its motive power. The electrically-driven device may be, for example, an electric vehicle or a robot. The electrically-driven vehicle may be a vehicle for carrying people or a vehicle for moving luggage. The electrically-driven vehicle may be an aerial work vehicle having a function of moving people vertically, or a loading vehicle having a function of moving luggage vertically. The loading vehicle may be, for example, a forklift or an automated guided vehicle (AGV). In one example, the battery management system 1 may estimate the degradation state of a storage battery mounted on a forklift.
図1は一例に係る電池管理システム1の機能構成を示す図である。電池管理システム1は、電動機器2に搭載または接続された蓄電池の劣化状態を推定する。一例では、電池管理システム1はサーバ10を備える。サーバ10は、電動機器2に搭載または接続された蓄電池の状態を示す蓄電池データを記憶するデータベース20に通信ネットワークを介してアクセスすることができる。データベース20は少なくとも一つの電動機器2のそれぞれの蓄電池データを記憶する。データベース20は電池管理システム1の構成要素でもよいし、電池管理システム1とは別のコンピュータシステム内に設けられてもよい。電池管理システム1のために用いられる通信ネットワークは、例えば、インターネットおよびイントラネットの少なくとも一方によって構成される。
FIG. 1 is a diagram showing the functional configuration of a battery management system 1 according to an example. The battery management system 1 estimates the degradation state of a storage battery mounted on or connected to an electrically-driven device 2. In one example, the battery management system 1 includes a server 10. The server 10 can access a database 20 that stores storage battery data indicating the state of the storage battery mounted on or connected to the electrically-driven device 2 via a communication network. The database 20 stores storage battery data for each of at least one electrically-driven device 2. The database 20 may be a component of the battery management system 1, or may be provided in a computer system separate from the battery management system 1. The communication network used for the battery management system 1 is, for example, composed of at least one of the Internet and an intranet.
個々の電動機器2は蓄電池データをデータベース20に提供する。一例では、電動機器2は、蓄電池を監視または制御するバッテリ・マネジメント・ユニット(BMU)3を備える。BMU3は蓄電池の状態を所与の時間間隔で繰り返し測定し、その状態を示す蓄電池データを生成する。そして、BMU3はその蓄電池データを所与のタイミングで通信ネットワークを介してデータベース20に向けて送信する。BMU3は電動機器2の外部に設けられてもよい。蓄電池データは蓄電池の状態を示す時系列データである。例えば、蓄電池データの個々のレコードは、測定日時と、蓄電池の状態を示す少なくとも一つの物理量とを含む。その物理量の例として測定電圧、測定電流、および測定温度が挙げられるが、これらに限定されない。例えば、蓄電池の個々のレコードが測定電流を含む場合、蓄電池が充電されている状態における測定電流は正の値として記録され、蓄電池が放電している状態における測定電流は負の値として記録される。蓄電池データは、例えば100ミリ秒毎に測定された物理量を示す。データベース20内では、蓄電池データは、蓄電池IDおよび電動機器IDのうちの少なくとも一つと関連付けられる。蓄電池IDは蓄電池を一意に特定する識別子である。電動機器IDは電動機器2を一意に特定する識別子である。
Each electric device 2 provides storage battery data to the database 20. In one example, the electric device 2 includes a battery management unit (BMU) 3 that monitors or controls the storage battery. The BMU 3 repeatedly measures the state of the storage battery at a given time interval and generates storage battery data indicating the state. The BMU 3 then transmits the storage battery data to the database 20 via a communication network at a given timing. The BMU 3 may be provided outside the electric device 2. The storage battery data is time-series data indicating the state of the storage battery. For example, each record of the storage battery data includes a measurement date and time and at least one physical quantity indicating the state of the storage battery. Examples of the physical quantity include, but are not limited to, a measured voltage, a measured current, and a measured temperature. For example, if each record of the storage battery includes a measured current, the measured current when the storage battery is charging is recorded as a positive value, and the measured current when the storage battery is discharging is recorded as a negative value. The storage battery data indicates a physical quantity measured, for example, every 100 milliseconds. In the database 20, the storage battery data is associated with at least one of a storage battery ID and an electric device ID. The storage battery ID is an identifier that uniquely identifies the storage battery. The electric device ID is an identifier that uniquely identifies the electric device 2.
サーバ10は、蓄電池データに基づいて蓄電池の劣化状態を推定するコンピュータである。サーバ10は、機能モジュールとして、取得部11、算出部12、推定部13、および出力部14を備える。取得部11は、蓄電池データをデータベース20から取得する機能モジュールである。算出部12は、取得された蓄電池データを用いて、蓄電池の放電に関する特性値を算出する機能モジュールである。推定部13は、算出された特性値に基づいて、蓄電池の劣化状態を推定する機能モジュールである。出力部14は、推定された劣化状態を含む処理結果を出力する機能モジュールである。
The server 10 is a computer that estimates the deterioration state of the storage battery based on the storage battery data. The server 10 has the following functional modules: an acquisition unit 11, a calculation unit 12, an estimation unit 13, and an output unit 14. The acquisition unit 11 is a functional module that acquires storage battery data from the database 20. The calculation unit 12 is a functional module that calculates characteristic values related to the discharge of the storage battery using the acquired storage battery data. The estimation unit 13 is a functional module that estimates the deterioration state of the storage battery based on the calculated characteristic values. The output unit 14 is a functional module that outputs processing results including the estimated deterioration state.
図2は、サーバ10を構成するコンピュータ100の一般的なハードウェア構成の一例を示す図である。例えば、コンピュータ100は、オペレーティングシステム、アプリケーション・プログラム等を実行するプロセッサ(例えばCPU)101と、ROMおよびRAMで構成される主記憶部102と、ハードディスク、フラッシュメモリ等の記憶装置で構成される補助記憶部103と、ネットワークカードまたは無線通信モジュールで構成される通信制御部104と、キーボード、マウス等の入力装置105と、モニタ等の出力装置106とを備える。
FIG. 2 is a diagram showing an example of a general hardware configuration of a computer 100 constituting the server 10. For example, the computer 100 comprises a processor (e.g., a CPU) 101 that executes an operating system, application programs, etc., a main memory unit 102 consisting of ROM and RAM, an auxiliary memory unit 103 consisting of a storage device such as a hard disk or flash memory, a communication control unit 104 consisting of a network card or wireless communication module, input devices 105 such as a keyboard and mouse, and an output device 106 such as a monitor.
サーバ10の各機能モジュールは、プロセッサ101または主記憶部102の上に予め定められたプログラムを読み込ませてプロセッサ101にそのプログラムを実行させることで実現される。プロセッサ101はそのプログラムに従って、通信制御部104、入力装置105、または出力装置106を動作させ、主記憶部102または補助記憶部103におけるデータの読み出しおよび書き込みを行う。処理に必要なデータまたはデータベースは主記憶部102または補助記憶部103内に格納される。
Each functional module of server 10 is realized by loading a predetermined program onto processor 101 or main memory unit 102 and having processor 101 execute the program. Processor 101 operates communication control unit 104, input device 105, or output device 106 in accordance with the program, and reads and writes data in main memory unit 102 or auxiliary memory unit 103. Data or databases required for processing are stored in main memory unit 102 or auxiliary memory unit 103.
サーバ10は少なくとも一つのコンピュータによって構成される。複数のコンピュータが用いられる場合には、これらのコンピュータがインターネット、イントラネット等の通信ネットワークを介して接続されることで、論理的に一つのサーバ10が構築される。
The server 10 is composed of at least one computer. When multiple computers are used, a single server 10 is logically constructed by connecting these computers via a communication network such as the Internet or an intranet.
コンピュータまたはコンピュータシステムを電池管理システム1またはサーバ10として機能させるための電池管理プログラムは、該コンピュータまたはコンピュータシステムを取得部11、算出部12、推定部13、および出力部14として機能させるためのプログラムコードを含む。この電池管理プログラムは、CD-ROM、DVD-ROM、半導体メモリ等の有形の記録媒体に非一時的に記録された上で提供されてもよい。あるいは、電池管理プログラムは、搬送波に重畳されたデータ信号として通信ネットワークを介して提供されてもよい。提供された電池管理プログラムは例えば補助記憶部103に記憶される。プロセッサ101が補助記憶部103からその電池管理プログラムを読み出して実行することで、上記の各機能モジュールが実現する。
The battery management program for causing a computer or computer system to function as the battery management system 1 or server 10 includes program code for causing the computer or computer system to function as an acquisition unit 11, a calculation unit 12, an estimation unit 13, and an output unit 14. This battery management program may be provided after being non-temporarily recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory. Alternatively, the battery management program may be provided via a communications network as a data signal superimposed on a carrier wave. The provided battery management program is stored in, for example, the auxiliary memory unit 103. The processor 101 reads out the battery management program from the auxiliary memory unit 103 and executes it to realize each of the above-mentioned functional modules.
電池管理システム1(サーバ10)による処理について説明する前に、算出部12が特性値を算出するために用いる複数のパラメータについて説明する。上述したように、算出部12は、蓄電池の放電に関する特性値を算出する。一例では、算出部12は、基準期間と対象期間とのそれぞれについて、特性値を算出する。本開示では、基準期間における特性値を「基準特性値」ともいい、対象期間における特性値を「対象特性値」ともいう。
Before describing the processing by the battery management system 1 (server 10), we will describe several parameters that the calculation unit 12 uses to calculate characteristic values. As described above, the calculation unit 12 calculates characteristic values related to the discharge of the storage battery. In one example, the calculation unit 12 calculates characteristic values for each of a reference period and a target period. In this disclosure, the characteristic values in the reference period are also referred to as "reference characteristic values," and the characteristic values in the target period are also referred to as "target characteristic values."
一例では、算出部12は、閉回路電圧(CCV)が満充電時の電圧から最低駆動電圧Vminに至るまでの放電時間を、特性値として算出する。以下では、「閉回路電圧(CCV)が満充電時の電圧から最低駆動電圧Vminに至るまでの放電時間」を単に「放電時間」という。算出部12は、電動機器2が最大放電電力Pmaxにより定電力放電を行った際の放電時間を、特性値として算出してもよい。最大放電電力Pmaxは、電動機器2を最高出力で動作させるために要求される電力を示す。最低駆動電圧Vminは、最大放電電力Pmaxを出力するために最低限必要となる電圧を示す。したがって、電動機器2におけるCCVが最低駆動電圧Vminを下回った場合には、該電動機器2は最大放電電力Pmaxで動作することができない。最大放電電力Pmaxと最低駆動電圧Vminとは電動機器2毎に設定された値であり、例えばデータベース20内に蓄電池IDおよび電動機器IDの少なくとも一つと関連付けられて記録される。満充電時とは、蓄電池に十分な電気が貯えられた時点のことをいい、例えば、蓄電池の充電状態を示すSOC(State Of Charge)が100%以上である時点をいう。
In one example, the calculation unit 12 calculates the discharge time required for the closed circuit voltage (CCV) to reach the minimum drive voltage V min from the voltage at full charge as the characteristic value. Hereinafter, the "discharge time required for the closed circuit voltage (CCV) to reach the minimum drive voltage V min from the voltage at full charge" is simply referred to as the "discharge time". The calculation unit 12 may calculate the discharge time when the electric device 2 performs constant power discharge with the maximum discharge power P max as the characteristic value. The maximum discharge power P max indicates the power required to operate the electric device 2 at the maximum output. The minimum drive voltage V min indicates the minimum voltage required to output the maximum discharge power P max . Therefore, when the CCV in the electric device 2 falls below the minimum drive voltage V min , the electric device 2 cannot operate at the maximum discharge power P max . The maximum discharge power P max and the minimum drive voltage V min are values set for each electric device 2, and are recorded in the database 20 in association with at least one of the storage battery ID and the electric device ID, for example. The fully charged state refers to the point in time when sufficient electricity is stored in the storage battery, for example, when the SOC (State Of Charge) indicating the charge state of the storage battery is 100% or more.
一例では、算出部12は放電時間を算出するために、最大放電電力Pmaxおよび最低駆動電圧Vminに加えて、SOCと開回路電圧(OCV)との関係を示すOCV-SOC特性と、SOCと直流抵抗(DCR)との関係を示すDCR-SOC特性を用いる。
In one example, in order to calculate the discharge time, the calculation unit 12 uses an OCV-SOC characteristic indicating the relationship between the SOC and an open circuit voltage (OCV) and a DCR-SOC characteristic indicating the relationship between the SOC and a direct current resistance (DCR), in addition to the maximum discharge power P max and the minimum drive voltage V min .
この例では、算出部12は、蓄電池の等価回路に基づく計算を実行する。等価回路は、SOCに比例して電圧が変わる電源と、SOCに比例して抵抗値が変わる内部抵抗とを含む。等価回路に基づく計算は、OCV-SOC特性を示す式と、DCR-SOC特性を示す式とを含む。
In this example, the calculation unit 12 performs calculations based on an equivalent circuit of the storage battery. The equivalent circuit includes a power source whose voltage changes in proportion to the SOC, and an internal resistance whose resistance value changes in proportion to the SOC. The calculations based on the equivalent circuit include an equation showing the OCV-SOC characteristics and an equation showing the DCR-SOC characteristics.
OCV-SOC特性は一次式(1)によって示されてもよいし、二次式(2)によって示されてもよい。
OCV=aOCV+bOCV・SOC …(1)
OCV=aOCV+bOCV・SOC+cOCV・SOC2 …(2)
式(1)でのaOCVおよびbOCVは一次近似定数であるといえ、式(2)でのaOCV,bOCV,およびcOCVは二次近似定数であるといえる。 The OCV-SOC characteristic may be expressed by a linear equation (1) or a quadratic equation (2).
OCV = a OCV + b OCV · SOC ... (1)
OCV = a OCV + b OCV · SOC + c OCV · SOC 2 ... (2)
It can be said that a OCV and b OCV in the formula (1) are first-order approximation constants, and a OCV , b OCV , and c OCV in the formula (2) are second-order approximation constants.
OCV=aOCV+bOCV・SOC …(1)
OCV=aOCV+bOCV・SOC+cOCV・SOC2 …(2)
式(1)でのaOCVおよびbOCVは一次近似定数であるといえ、式(2)でのaOCV,bOCV,およびcOCVは二次近似定数であるといえる。 The OCV-SOC characteristic may be expressed by a linear equation (1) or a quadratic equation (2).
OCV = a OCV + b OCV · SOC ... (1)
OCV = a OCV + b OCV · SOC + c OCV · SOC 2 ... (2)
It can be said that a OCV and b OCV in the formula (1) are first-order approximation constants, and a OCV , b OCV , and c OCV in the formula (2) are second-order approximation constants.
DCR-SOC特性は一次式(3)によって示されてもよいし、二次式(4)によって示されてもよい。
DCR=aDCR+bDCR・SOC …(3)
DCR=aDCR+bDCR・SOC+cDCR・SOC2 …(4)
式(3)でのaDCRおよびbDCRは一次近似定数であるといえ、式(4)でのaDCR,bDCR,およびcDCRは二次近似定数であるといえる。 The DCR-SOC characteristic may be expressed by the linear equation (3) or the quadratic equation (4).
DCR = a DCR + b DCR · SOC ... (3)
DCR = a DCR + b DCR · SOC + c DCR · SOC 2 ... (4)
It can be said that aDCR and bDCR in equation (3) are first-order approximation constants, and aDCR , bDCR , and cDCR in equation (4) are second-order approximation constants.
DCR=aDCR+bDCR・SOC …(3)
DCR=aDCR+bDCR・SOC+cDCR・SOC2 …(4)
式(3)でのaDCRおよびbDCRは一次近似定数であるといえ、式(4)でのaDCR,bDCR,およびcDCRは二次近似定数であるといえる。 The DCR-SOC characteristic may be expressed by the linear equation (3) or the quadratic equation (4).
DCR = a DCR + b DCR · SOC ... (3)
DCR = a DCR + b DCR · SOC + c DCR · SOC 2 ... (4)
It can be said that aDCR and bDCR in equation (3) are first-order approximation constants, and aDCR , bDCR , and cDCR in equation (4) are second-order approximation constants.
[システムの動作]
図3~図8を参照しながら、電池管理システム1(サーバ10)による処理の一例を説明するとともに本実施形態に係る電池管理方法について説明する。図3は、電池管理システムによる処理の一例を示すフロチャートである。図4および図5は、SOCの時系列データの例を示す図である。図6は、OCV-SOC特性に関するグラフの例を示す図である。図7は、DCR-SOC特性に関するグラフの例を示す図である。図8は、基準特性値および対象特性値に関するグラフの例を示す図である。 [System Operation]
An example of processing by the battery management system 1 (server 10) will be described with reference to Figures 3 to 8, and a battery management method according to this embodiment will be described. Figure 3 is a flowchart showing an example of processing by the battery management system. Figures 4 and 5 are diagrams showing examples of time-series data of SOC. Figure 6 is a diagram showing an example of a graph relating to OCV-SOC characteristics. Figure 7 is a diagram showing an example of a graph relating to DCR-SOC characteristics. Figure 8 is a diagram showing an example of a graph relating to a reference characteristic value and a target characteristic value.
図3~図8を参照しながら、電池管理システム1(サーバ10)による処理の一例を説明するとともに本実施形態に係る電池管理方法について説明する。図3は、電池管理システムによる処理の一例を示すフロチャートである。図4および図5は、SOCの時系列データの例を示す図である。図6は、OCV-SOC特性に関するグラフの例を示す図である。図7は、DCR-SOC特性に関するグラフの例を示す図である。図8は、基準特性値および対象特性値に関するグラフの例を示す図である。 [System Operation]
An example of processing by the battery management system 1 (server 10) will be described with reference to Figures 3 to 8, and a battery management method according to this embodiment will be described. Figure 3 is a flowchart showing an example of processing by the battery management system. Figures 4 and 5 are diagrams showing examples of time-series data of SOC. Figure 6 is a diagram showing an example of a graph relating to OCV-SOC characteristics. Figure 7 is a diagram showing an example of a graph relating to DCR-SOC characteristics. Figure 8 is a diagram showing an example of a graph relating to a reference characteristic value and a target characteristic value.
ステップS1では、取得部11がデータ特定情報を取得する。データ特定情報とは、蓄電池データをデータベース20から読み出すために用いられる情報である。一例では、データ特定情報は、蓄電池IDおよび電動機器IDのうちの少なくとも一つと、最大放電電力Pmaxと、最低駆動電圧Vminと、基準期間と、対象期間とを含む。例えば、基準期間は蓄電池が新品である時期に対応し、対象期間は現在時点を含む過去の時期に対応してもよい。基準期間および対象期間は所定の時間幅によって設定される。その時間幅は複数回の充電および放電の実施が期待される期間であってもよく、例えば3日間等のような複数の日にちにわたって設定されてもよい。取得部11は電池管理システム1のユーザによって入力されたデータ特定情報を受け付けてもよいし、所与のルールに基づいてデータ特定情報を自動的に設定してもよい。
In step S1, the acquisition unit 11 acquires data identification information. The data identification information is information used to read out storage battery data from the database 20. In one example, the data identification information includes at least one of a storage battery ID and an electric device ID, a maximum discharge power Pmax , a minimum driving voltage Vmin , a reference period, and a target period. For example, the reference period may correspond to a time when the storage battery is new, and the target period may correspond to a past time including the current time. The reference period and the target period are set by a predetermined time width. The time width may be a period during which multiple charging and discharging are expected to be performed, and may be set over multiple days, such as three days. The acquisition unit 11 may accept data identification information input by a user of the battery management system 1, or may automatically set the data identification information based on a given rule.
ステップS2では、取得部11が、基準期間に対応する蓄電池データを基準データとして取得する。取得部11は、蓄電池IDおよび電動機器IDの少なくとも一つと基準期間とに対応する蓄電池のレコード群をデータベース20から読み出す。
In step S2, the acquisition unit 11 acquires storage battery data corresponding to the reference period as reference data. The acquisition unit 11 reads from the database 20 a group of records of storage batteries that correspond to at least one of the storage battery ID and the electric device ID and the reference period.
ステップS3では、算出部12が、ステップS2にて取得された基準データと、最低駆動電圧Vminとに基づいて、基準特性値を算出する。
In step S3, the calculation unit 12 calculates a reference characteristic value based on the reference data acquired in step S2 and the minimum drive voltage Vmin .
一例では、算出部12は、時間軸に沿って設定された複数の区間のそれぞれについて、測定電圧および測定電流の移動平均を算出する。例えば、レコード間の時間間隔が100ミリ秒である場合に、算出部12はその区間を10秒と設定し、その区間内の100個の物理量の平均値を10秒ごとに算出する。
In one example, the calculation unit 12 calculates moving averages of the measured voltage and measured current for each of a number of intervals set along the time axis. For example, if the time interval between records is 100 milliseconds, the calculation unit 12 sets the interval to 10 seconds and calculates the average value of 100 physical quantities within that interval every 10 seconds.
続いて、算出部12は、移動平均が得られたそれぞれの区間kについてSOC(k)を式(5)により算出する。
SOC(k)=1-Σ{I(k)/α}/Wbat …(5)
ここで、Wbatは蓄電池の定格容量を示し、I(k)は区間kでの測定電流を示す。αは電流(A)を容量(Ah)に変換するための係数である。もし区間の長さが10秒であれば、α=360である。Σ{I(k)/α}は、区間kまでにおける蓄電池の消費容量を示す。上述したように、データベース20には、蓄電池が充電されている状態における測定電流は正の値として記録され、蓄電池が放電している状態における測定電流は負の値として記録されている。したがって、Σ{I(k)/α}は、区間kまでにおける蓄電池の容量積算値ともいえる。 Next, thecalculation unit 12 calculates the SOC(k) for each interval k for which the moving average has been obtained, using equation (5).
SOC(k)=1−Σ{I(k)/α}/W bat ... (5)
Here, W bat indicates the rated capacity of the storage battery, and I(k) indicates the measured current in section k. α is a coefficient for converting current (A) to capacity (Ah). If the length of the section is 10 seconds, α=360. Σ{I(k)/α} indicates the consumed capacity of the storage battery up to section k. As described above, in thedatabase 20, the measured current when the storage battery is in a charging state is recorded as a positive value, and the measured current when the storage battery is in a discharging state is recorded as a negative value. Therefore, Σ{I(k)/α} can also be said to be the integrated capacity value of the storage battery up to section k.
SOC(k)=1-Σ{I(k)/α}/Wbat …(5)
ここで、Wbatは蓄電池の定格容量を示し、I(k)は区間kでの測定電流を示す。αは電流(A)を容量(Ah)に変換するための係数である。もし区間の長さが10秒であれば、α=360である。Σ{I(k)/α}は、区間kまでにおける蓄電池の消費容量を示す。上述したように、データベース20には、蓄電池が充電されている状態における測定電流は正の値として記録され、蓄電池が放電している状態における測定電流は負の値として記録されている。したがって、Σ{I(k)/α}は、区間kまでにおける蓄電池の容量積算値ともいえる。 Next, the
SOC(k)=1−Σ{I(k)/α}/W bat ... (5)
Here, W bat indicates the rated capacity of the storage battery, and I(k) indicates the measured current in section k. α is a coefficient for converting current (A) to capacity (Ah). If the length of the section is 10 seconds, α=360. Σ{I(k)/α} indicates the consumed capacity of the storage battery up to section k. As described above, in the
さらに、算出部12は、算出された各SOC(k)に基づいて、それぞれの区間kについて経過時間ETを算出する。経過時間ETは、直近のSOCが100%であった時点からの経過時間を示す。
Furthermore, the calculation unit 12 calculates the elapsed time ET for each section k based on each calculated SOC(k). The elapsed time ET indicates the time elapsed since the most recent SOC was 100%.
この結果、算出部12は、n個の区間kのそれぞれについて、測定電流I(k)、測定電圧MV(k)、SOC(k)、および経過時間ET(k)を得る(k=1~n)。すなわち、算出部12は測定電流の移動平均と、測定電圧の移動平均と、対応するSOCと、対応する経過時間とについての時系列データを得る。一例では、算出部12によって取得される時系列データの個々のレコードは、測定電流の移動平均と、測定電圧の移動平均と、対応するSOCと、対応する経過時間ETとを含む。
As a result, the calculation unit 12 obtains the measured current I(k), measured voltage MV(k), SOC(k), and elapsed time ET(k) for each of the n intervals k (k=1 to n). That is, the calculation unit 12 obtains time series data for the moving average of the measured current, the moving average of the measured voltage, the corresponding SOC, and the corresponding elapsed time. In one example, each record of the time series data obtained by the calculation unit 12 includes the moving average of the measured current, the moving average of the measured voltage, the corresponding SOC, and the corresponding elapsed time ET.
続いて、算出部12は、得られた時系列データのうち、特性値を算出するために用いられる有効区間の時系列データを有効時系列データとして選択する。一例では、算出部12は、劣化状態の推定における誤差の要因になり得る無効区間の時系列データを無効時系列データとして除外し、残った有効区間の時系列データを有効時系列データとして選択する。
Then, the calculation unit 12 selects, from the obtained time series data, the time series data of the valid section used to calculate the characteristic value as valid time series data. In one example, the calculation unit 12 excludes the time series data of the invalid section that may be a cause of error in estimating the degradation state as invalid time series data, and selects the remaining time series data of the valid section as valid time series data.
一例では、無効区間は、蓄電池の満充電が終了した時点から、所定時間Taが経過するまでの時間区間を含んでもよい。以下ではこの時間区間を第1無効区間ともいう。所定時間Taは例えば1時間であってもよい。
In one example, the invalid section may include a time period from when the storage battery is fully charged to when a predetermined time Ta has elapsed. Hereinafter, this time period is also referred to as a first invalid section. The predetermined time Ta may be, for example, one hour.
あるいは、無効区間は、充電時間が閾値Tb未満である蓄電池の充電が終了した時点から該充電時間分の時間が経過するまでの時間区間を含んでもよい。以下ではこの時間区間を第2無効区間ともいう。閾値Tbは例えば1時間であってもよい。
Alternatively, the invalid section may include a time section from the point at which charging of a storage battery whose charging time is less than the threshold Tb is completed until the time equivalent to the charging time has elapsed. Hereinafter, this time section is also referred to as a second invalid section. The threshold Tb may be, for example, one hour.
あるいは、無効区間は、SOCが閾値Ca%以上の状態で開始され、且つ、SOCが100%未満の状態で終了した充電の終了時点から、次に蓄電池が満充電されるまでの時間区間を含んでもよい。以下ではこの時間区間を第3無効区間ともいう。閾値Caは例えば90%でもよい。
Alternatively, the invalid section may include a time period from the end of charging that starts when the SOC is equal to or greater than the threshold value Ca% and ends when the SOC is less than 100% until the next time the storage battery is fully charged. Hereinafter, this time period is also referred to as the third invalid section. The threshold value Ca may be, for example, 90%.
図4を参照しながら、第3無効区間の一例を説明する。図4に示すグラフの横軸は時刻tを示し、縦軸はSOC(%)を示す。図4に示される例において閾値Caは90%であるとする。時刻t1においてSOCが90%以上の状態で充電が開始され、時刻t2においてSOCが100%未満の状態で充電が終了している。その後、時刻t3において蓄電池が満充電される。この例では、算出部12は時刻t2から時刻t3までの時間帯を第3無効区間として特定する。
An example of the third invalid section will be described with reference to FIG. 4. The horizontal axis of the graph shown in FIG. 4 indicates time t, and the vertical axis indicates SOC (%). In the example shown in FIG. 4, the threshold value Ca is 90%. At time t1, charging begins with an SOC of 90% or more, and at time t2, charging ends with an SOC of less than 100%. Thereafter, at time t3, the storage battery is fully charged. In this example, the calculation unit 12 identifies the time period from time t2 to time t3 as the third invalid section.
第3無効区間に関する別の例として、無効区間は、SOCが閾値Ca%以上の状態で開始され、SOCの上昇量がCi%以上であり、且つ、SOCが100%未満の状態で終了した充電の終了時点から、次に蓄電池が満充電されるまでの時間区間を含んでもよい。閾値Ciは例えば3%でもよい。
As another example of the third invalid section, the invalid section may include a time period from the end of charging that starts when the SOC is equal to or greater than a threshold value Ca%, when the SOC has increased by equal to or greater than Ci%, and when the SOC is less than 100%, until the next time the storage battery is fully charged. The threshold value Ci may be, for example, 3%.
あるいは、無効区間は、前回の満充電からSOCが閾値Cb%を超えることなくSOCの累積減少値が100%に達した時点から、次に蓄電池が満充電されるまでの時間区間を含んでもよい。SOCの累積減少値とは、放電の間に蓄電池が充電されたか否かにかかわらず、消費されたSOCの積算値をいう。以下ではその時間区間を第4無効区間ともいう。閾値Cbは例えば90%でもよい。
Alternatively, the invalid section may include a time period from when the cumulative decrease in SOC reaches 100% without the SOC exceeding the threshold Cb% since the previous full charge to when the storage battery is next fully charged. The cumulative decrease in SOC refers to the integrated value of the SOC consumed, regardless of whether the storage battery is charged during discharging. Hereinafter, this time period is also referred to as the fourth invalid section. The threshold Cb may be, for example, 90%.
図5を参照しながら、第4無効区間の一例を説明する。図5に示すグラフの横軸は時刻tを示し、縦軸はSOC(%)を示す。図5に示される例において閾値Cbは90%であるとする。時刻t4において前回の満充電が終了し、時刻t5において次の満充電が終了している。時刻t4から時刻t5までの間においても蓄電池は何度か充電されているが、この時間帯においてSOCは90%を超えていない。時刻t6において、時刻t4で満充電された蓄電池のSOCの累積減少値が100%に達する。この例では、算出部12は時刻t6から時刻t5までの時間帯を第4無効区間として特定する。
An example of the fourth invalid section will be described with reference to FIG. 5. The horizontal axis of the graph shown in FIG. 5 indicates time t, and the vertical axis indicates SOC (%). In the example shown in FIG. 5, the threshold Cb is 90%. The previous full charge is completed at time t4, and the next full charge is completed at time t5. The storage battery is charged several times between time t4 and time t5, but the SOC does not exceed 90% during this time period. At time t6, the cumulative decrease in SOC of the storage battery that was fully charged at time t4 reaches 100%. In this example, the calculation unit 12 identifies the time period from time t6 to time t5 as the fourth invalid section.
一例では、算出部12は、第1~第4無効区間のうちの少なくとも一つでの時系列データを無効時系列データとして除外し、残った有効区間の時系列データを有効時系列データとして選択する。
In one example, the calculation unit 12 excludes the time series data in at least one of the first to fourth invalid intervals as invalid time series data, and selects the time series data in the remaining valid intervals as valid time series data.
続いて、算出部12は統計的手法により、有効時系列データに基づいてOCR-SOC特性およびDCR-SOC特性を算出する。例えば、算出部12は式(1)で示されるOCR-SOC特性と、式(4)で示されるDCR-SOC特性とを算出する。一例として、算出部12はその統計的手法として、非線形の最小二乗法であるマルカート(Marquardt)法を用いてもよい。算出部12はこのマルカート法を用いて、測定電圧MVと理論電圧CVとの平均二乗誤差が最小となる、一次近似定数aOCVおよびbOCVと二次近似定数aDCR,bDCR,およびcDCRとを算出することで、OCV-SOC特性およびDCR-SOC特性を算出する。一例では、区間kでの理論電圧CVは式(6)により得られる。式(6)は、蓄電池の等価回路に基づく蓄電池のI-V特性を表すといえ、理論電圧の計算式であるともいえる。
CV(k)=OCV(k)-I(k)・DCR(k)={aOCV+bOCV・SOC(k)}-I(k)・{aDCR+bDCR・SOC(k)+cDCR・SOC(k)2} …(6) Next, thecalculation unit 12 calculates the OCR-SOC characteristic and the DCR-SOC characteristic based on the effective time series data by a statistical method. For example, the calculation unit 12 calculates the OCR-SOC characteristic shown in formula (1) and the DCR-SOC characteristic shown in formula (4). As an example, the calculation unit 12 may use the Marquardt method, which is a nonlinear least square method, as the statistical method. The calculation unit 12 calculates the OCV-SOC characteristic and the DCR-SOC characteristic by using the Marquardt method to calculate the first-order approximation constants a OCV and b OCV and the second-order approximation constants a DCR , b DCR , and c DCR that minimize the mean square error between the measured voltage MV and the theoretical voltage CV. In one example, the theoretical voltage CV in the section k is obtained by formula (6). Formula (6) can be said to represent the IV characteristic of the storage battery based on the equivalent circuit of the storage battery, and can also be said to be a calculation formula for the theoretical voltage.
CV(k)=OCV(k)-I(k)·DCR(k)={ aOCV + bOCV ·SOC(k)}-I(k)·{ aDCR + bDCR ·SOC(k)+ cDCR ·SOC(k) 2 }...(6)
CV(k)=OCV(k)-I(k)・DCR(k)={aOCV+bOCV・SOC(k)}-I(k)・{aDCR+bDCR・SOC(k)+cDCR・SOC(k)2} …(6) Next, the
CV(k)=OCV(k)-I(k)·DCR(k)={ aOCV + bOCV ·SOC(k)}-I(k)·{ aDCR + bDCR ·SOC(k)+ cDCR ·SOC(k) 2 }...(6)
あるいは、算出部12は統計的手法として多変量解析を用いてもよい。一例では、算出部12は式(6)に基づいて一次近似定数aOCVおよびbOCVと二次近似定数aDCR,bDCR,およびcDCRとを算出してもよい。
Alternatively, the calculation unit 12 may use multivariate analysis as a statistical method. In one example, the calculation unit 12 may calculate the first-order approximation constants aOCV and bOCV and the second-order approximation constants aDCR , bDCR , and cDCR based on the formula (6).
すなわち、まず、算出部12はマルカート法、多変量解析等のような統計的手法を用いて、測定電圧MVと理論電圧CVとの平均二乗誤差が最小となるようにI-V特性を算出する。続いて、算出部12は、そのI-V特性に基づいて一次近似定数aOCVおよびbOCVと二次近似定数aDCR,bDCR,およびcDCRとを算出することで、OCV-SOC特性およびDCR-SOC特性を算出する。
That is, first, the calculation unit 12 calculates the IV characteristics so as to minimize the mean square error between the measured voltage MV and the theoretical voltage CV using a statistical method such as the Marquardt method, multivariate analysis, etc. Next, the calculation unit 12 calculates the first-order approximation constants aOCV and bOCV and the second-order approximation constants aDCR , bDCR , and cDCR based on the IV characteristics, thereby calculating the OCV-SOC characteristics and the DCR-SOC characteristics.
続いて、算出部12は、算出されたOCV-SOC特性およびDCR-SOC特性に基づいて、有効時系列データ内の各時点におけるOCVおよびDCRを算出する。一例では、算出部12は、式(1)にて示されるOCV-SOC特性および式(4)にて示されるDCR-SOC特性に各時点におけるSOCを代入することで、対応するOCVおよびDCRを算出する。
Then, the calculation unit 12 calculates the OCV and DCR at each time point in the valid time series data based on the calculated OCV-SOC characteristic and DCR-SOC characteristic. In one example, the calculation unit 12 calculates the corresponding OCV and DCR by substituting the SOC at each time point into the OCV-SOC characteristic shown in formula (1) and the DCR-SOC characteristic shown in formula (4).
続いて、算出部12は、OCVおよびDCRと、最大放電電力Pmaxと、CCVとの関係を示す式(7)を、CCVについて解くことにより、有効時系列データ内の各時点におけるCCVを算出する。すなわち、算出部12は、各時点におけるOCVおよびDCRと、最大放電電力Pmaxとに基づいて、対応するCCVを式(8)にて算出する。
CCV=OCV-Pmax/CCV・DCR …(7)
CCV=(OCV+sqrt(OCV2-4・Pmax・DCR)/2 …(8) Next, thecalculation unit 12 calculates the CCV at each time point in the valid time-series data by solving the equation (7) showing the relationship between the OCV and DCR, the maximum discharge power Pmax , and the CCV. That is, the calculation unit 12 calculates the corresponding CCV based on the OCV and DCR at each time point and the maximum discharge power Pmax using the equation (8).
CCV=OCV- Pmax /CCV·DCR (7)
CCV = (OCV + sqrt (OCV 2 - 4 · P max · DCR) / 2 ... (8)
CCV=OCV-Pmax/CCV・DCR …(7)
CCV=(OCV+sqrt(OCV2-4・Pmax・DCR)/2 …(8) Next, the
CCV=OCV- Pmax /CCV·DCR (7)
CCV = (OCV + sqrt (OCV 2 - 4 · P max · DCR) / 2 ... (8)
算出部12は、算出された各時点におけるOCV、DCR、およびCCVを、有効時系列データの個々のレコードに追加する。したがって、一例では、有効時系列データの個々のレコードは、測定電流の移動平均、測定電圧の移動平均と、対応するSOCと、対応する経過時間ETと、対応するOCV、DCR、およびCCVと、を含む。
The calculation unit 12 adds the calculated OCV, DCR, and CCV at each time point to each record of the valid time series data. Thus, in one example, each record of the valid time series data includes a moving average of the measured current, a moving average of the measured voltage, a corresponding SOC, a corresponding elapsed time ET, and a corresponding OCV, DCR, and CCV.
続いて、算出部12は、式(8)にて算出された各時点におけるCCVと、対応する経過時間ETとに基づいて、基準期間における放電時間を基準特性値として算出する。算出部12は、CCVが最低駆動電圧Vminに至った時点における経過時間ETをその放電時間として取得してもよい。以下ではその経過時間をETVminと表す。上述したように、基準期間において複数回の充電および放電が行われる可能性があるので、CCVが最低駆動電圧Vminに至る現象が基準期間において複数回発生し得る。この場合に、算出部12は複数の経過時間ETVminの統計値を放電時間として算出してもよい。その統計値は例えば平均値でもよいし中央値でもよい。あるいは、基準期間においてCCVが最低駆動電圧Vminに至る現象の回数にかかわらず、算出部12は各時点におけるCCVおよび経過時間ETのペアに基づいて、CCVと経過時間ETとの関係を示す回帰式を算出し、その回帰式に最低駆動電圧Vminを適用して放電時間を算出してもよい。式(8)にて算出されるCCVは、基準期間におけるOCV-SOC特性およびDCR-SOC特性に基づく。したがって、算出部12は、最低駆動電圧Vminに加えて、基準期間におけるOCV-SOC特性およびDCR-SOC特性に基づいて、基準特性値を算出するともいえる。
Next, the calculation unit 12 calculates the discharge time in the reference period as a reference characteristic value based on the CCV at each time point calculated by formula (8) and the corresponding elapsed time ET. The calculation unit 12 may obtain the elapsed time ET at the time point when the CCV reaches the minimum drive voltage V min as the discharge time. Hereinafter, the elapsed time is represented as ET Vmin . As described above, since there is a possibility that charging and discharging are performed multiple times in the reference period, the phenomenon in which the CCV reaches the minimum drive voltage V min may occur multiple times in the reference period. In this case, the calculation unit 12 may calculate the statistical value of multiple elapsed times ET Vmin as the discharge time. The statistical value may be, for example, an average value or a median value. Alternatively, regardless of the number of times the phenomenon in which the CCV reaches the minimum drive voltage V min occurs in the reference period, the calculation unit 12 may calculate a regression equation indicating the relationship between the CCV and the elapsed time ET based on the pair of the CCV and the elapsed time ET at each time point, and apply the minimum drive voltage V min to the regression equation to calculate the discharge time. The CCV calculated by the formula (8) is based on the OCV-SOC characteristic and the DCR-SOC characteristic in the reference period. Therefore, it can be said that the calculation unit 12 calculates the reference characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic in the reference period in addition to the minimum drive voltage Vmin .
ステップS4では、取得部11が、対象期間に対応する蓄電池データを対象データとして取得する。取得部11は、蓄電池IDおよび電動機器IDの少なくとも一つと対象期間とに対応する蓄電池データのレコード群をデータベース20から読み出す。
In step S4, the acquisition unit 11 acquires storage battery data corresponding to the target period as target data. The acquisition unit 11 reads out a group of records of storage battery data corresponding to at least one of the storage battery ID and the electric device ID and the target period from the database 20.
ステップS5では、算出部12が、ステップS4にて取得された対象データと、最低駆動電圧Vminとに基づいて、対象特性値を算出する。一例では、算出部12は基準特性値と同様の手法で対象特性値を算出する。すなわち、算出部12は測定電圧および測定電流の移動平均を所定の区間ごとに算出する。続いて、算出部12はその区間ごとにSOCを算出する。続いて、算出部12は、対象期間における、測定電流の移動平均と、測定電圧の移動平均と、対応するSOCと、対応する経過時間ETとについての時系列データを得る。続いて、算出部12は、得られた時系列データから有効時系列データを選択する。
In step S5, the calculation unit 12 calculates the target characteristic value based on the target data acquired in step S4 and the minimum driving voltage Vmin . In one example, the calculation unit 12 calculates the target characteristic value in the same manner as the reference characteristic value. That is, the calculation unit 12 calculates the moving average of the measured voltage and the measured current for each predetermined interval. Then, the calculation unit 12 calculates the SOC for each interval. Then, the calculation unit 12 obtains time series data for the moving average of the measured current, the moving average of the measured voltage, the corresponding SOC, and the corresponding elapsed time ET during the target period. Then, the calculation unit 12 selects valid time series data from the obtained time series data.
続いて、算出部12は、その有効時系列データに基づいて、対象期間におけるI-V特性を統計的手法により算出し、そのI-V特性に基づいて一次近似定数aOCVおよびbOCVと二次近似定数aDCR,bDCR,およびcDCRとを算出することで、OCV-SOC特性およびDCR-SOC特性を算出する。
Next, the calculation unit 12 calculates the IV characteristic for the target period using a statistical method based on the valid time series data, and calculates the first-order approximation constants a OCV and b OCV and the second-order approximation constants a DCR , b DCR , and c DCR based on the IV characteristic, thereby calculating the OCV-SOC characteristic and the DCR-SOC characteristic.
続いて、算出部12は、OCV-SOC特性およびDCR-SOC特性によって得られる各時点でのOCVおよびDCRと、最大放電電力Pmaxとに基づいて、有効時系列データ内の各時点におけるCCVを算出する。そして、算出部12は算出した各時点におけるCCVと、対応する経過時間ETとに基づいて、対象期間における放電時間を対象特性値として算出する。基準期間についての処理と同様に、算出部12は複数の経過時間ETVminの統計値を放電時間として算出してもよいし、回帰式によって放電時間を算出してもよい。基準特性値の算出と同様に、算出部12は、最低駆動電圧Vminに加えて、対象期間におけるOCV-SOC特性およびDCR-SOC特性に基づいて、対象特性値を算出するともいえる。
Next, the calculation unit 12 calculates the CCV at each time point in the valid time series data based on the OCV and DCR at each time point obtained by the OCV-SOC characteristic and the DCR-SOC characteristic, and the maximum discharge power P max . Then, the calculation unit 12 calculates the discharge time in the target period as the target characteristic value based on the calculated CCV at each time point and the corresponding elapsed time ET. As in the process for the reference period, the calculation unit 12 may calculate the statistical value of a plurality of elapsed times ET Vmin as the discharge time, or may calculate the discharge time by a regression equation. As in the calculation of the reference characteristic value, the calculation unit 12 may calculate the target characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic in the target period in addition to the minimum drive voltage V min .
ステップS6では、算出部12が基準特性値と対象特性値との関係を算出する。一例では、基準特性値と対象特性値との比を、基準特性値と対象特性値との関係として算出する。あるいは、基準特性値と対象特性値との差分を、基準特性値と対象特性値との関係として算出してもよい。基準特性値と対象特性値との関係は、基準期間から対象期間への時間の経過に伴って蓄電池の特性がどのように変化したかを示す。したがって、両者の関係は、蓄電池の劣化状態を示すSOH(State Of Health)を表すともいえる。
In step S6, the calculation unit 12 calculates the relationship between the reference characteristic value and the target characteristic value. In one example, the ratio between the reference characteristic value and the target characteristic value is calculated as the relationship between the reference characteristic value and the target characteristic value. Alternatively, the difference between the reference characteristic value and the target characteristic value may be calculated as the relationship between the reference characteristic value and the target characteristic value. The relationship between the reference characteristic value and the target characteristic value indicates how the characteristics of the storage battery have changed over time from the reference period to the target period. Therefore, the relationship between the two can be said to represent the SOH (State of Health), which indicates the deterioration state of the storage battery.
算出部12は、放電時間に関する比を基準期間と対象特性値との関係として算出してもよい。一例では、算出部12は、基準期間における放電時間と、対象期間における放電時間との関係を示す比を、基準特性値と対象特性値との関係として算出する。本開示では、この関係を「SOH-P」ともいう。
The calculation unit 12 may calculate a ratio relating to the discharge time as the relationship between the reference period and the target characteristic value. In one example, the calculation unit 12 calculates a ratio indicating the relationship between the discharge time in the reference period and the discharge time in the target period as the relationship between the reference characteristic value and the target characteristic value. In the present disclosure, this relationship is also referred to as "SOH-P."
ステップS7では、推定部13が基準特性値と対象特性値との関係に基づいて、蓄電池の劣化状態を推定する。一例では、推定部13は、基準期間における放電時間と対象期間における放電時間との比に基づいて、蓄電池の劣化状態を推定する。あるいは、推定部13は、基準特性値と対象特性値との差分に基づいて、蓄電池の劣化状態を推定してもよい。
In step S7, the estimation unit 13 estimates the degraded state of the storage battery based on the relationship between the reference characteristic value and the target characteristic value. In one example, the estimation unit 13 estimates the degraded state of the storage battery based on the ratio between the discharge time in the reference period and the discharge time in the target period. Alternatively, the estimation unit 13 may estimate the degraded state of the storage battery based on the difference between the reference characteristic value and the target characteristic value.
ステップS8では、出力部14が処理結果を出力する、一例では、出力部14は、推定部13により推定された蓄電池の劣化状態を処理結果として出力する。あるいは、出力部14は、その劣化状態に加えて、算出部12により算出された基準特性値と対象特性値との関係を処理結果として出力する。上述したように、その関係は、基準特性値と対象特性値との比であってもよく、基準特性値と対象特性値との差分であってもよい。出力部14は、電池管理システム1での後続処理のために電池管理システム1内の別の機能モジュールに蓄電池の劣化状態を出力してもよい。あるいは、出力部14はメモリ、データベース等の所定の記憶装置に蓄電池の劣化状態を格納してもよい。あるいは、出力部14は蓄電池の劣化状態を表示装置上に表示してもよい。あるいは、出力部14は他のコンピュータシステムに向けて蓄電池の劣化状態を送信してもよい。
In step S8, the output unit 14 outputs the processing result. In one example, the output unit 14 outputs the deterioration state of the storage battery estimated by the estimation unit 13 as the processing result. Alternatively, the output unit 14 outputs the relationship between the reference characteristic value and the target characteristic value calculated by the calculation unit 12 as the processing result in addition to the deterioration state. As described above, the relationship may be the ratio between the reference characteristic value and the target characteristic value, or the difference between the reference characteristic value and the target characteristic value. The output unit 14 may output the deterioration state of the storage battery to another functional module in the battery management system 1 for subsequent processing in the battery management system 1. Alternatively, the output unit 14 may store the deterioration state of the storage battery in a predetermined storage device such as a memory or a database. Alternatively, the output unit 14 may display the deterioration state of the storage battery on a display device. Alternatively, the output unit 14 may transmit the deterioration state of the storage battery to another computer system.
図6~図8を参照しながら、基準期間および対象期間のそれぞれにおける蓄電池の特性の一例を説明する。この例では、基準期間は蓄電池が新品である期間に対応し、対象期間は蓄電池が劣化している期間に対応する。算出部12は、図6に示されるようなOCV-SOC特性を算出し、図7に示されるようなDCR-SOC特性を算出する。図6において、グラフ201は基準期間におけるOCV-SOC特性を示し、グラフ202は対象期間におけるOCV-SOC特性を示す。図7において、グラフ211は基準期間におけるDCR-SOC特性を示し、グラフ212は対象期間におけるDCR-SOC特性を示す。
With reference to Figures 6 to 8, an example of the characteristics of a storage battery in each of a reference period and a target period will be described. In this example, the reference period corresponds to a period during which the storage battery is new, and the target period corresponds to a period during which the storage battery is degraded. The calculation unit 12 calculates the OCV-SOC characteristics as shown in Figure 6, and calculates the DCR-SOC characteristics as shown in Figure 7. In Figure 6, graph 201 shows the OCV-SOC characteristics in the reference period, and graph 202 shows the OCV-SOC characteristics in the target period. In Figure 7, graph 211 shows the DCR-SOC characteristics in the reference period, and graph 212 shows the DCR-SOC characteristics in the target period.
図8は図6および図7に対応する。横軸は時間(h)を示し、縦軸はCCV(V)を示す。図8において、グラフ221は基準期間における放電時間を示し、グラフ222は対象期間における放電時間を示す。グラフ221,222から分かるように、蓄電池が劣化していくに伴って、CCVが最低駆動電圧Vminに至るまでの時間が短くなる。基準特性値に対する対象特性値の割合をSOH-Pとして示すとすると、蓄電池の劣化に伴ってSOH-Pは1.0(または100%)から徐々に下がっていく。一例では、SOH-Pが0.5(または50%)以下である場合には、蓄電池の製品寿命が末期である蓋然性が高い。このように、SOH-Pの値、すなわち基準特性値と対象特性値との関係により、蓄電池の劣化状態を推定することができる。
FIG. 8 corresponds to FIG. 6 and FIG. 7. The horizontal axis indicates time (h), and the vertical axis indicates CCV (V). In FIG. 8, graph 221 indicates the discharge time in the reference period, and graph 222 indicates the discharge time in the target period. As can be seen from graphs 221 and 222, as the storage battery deteriorates, the time it takes for the CCV to reach the minimum driving voltage Vmin becomes shorter. If the ratio of the target characteristic value to the reference characteristic value is represented as SOH-P, the SOH-P gradually decreases from 1.0 (or 100%) as the storage battery deteriorates. In one example, when the SOH-P is 0.5 (or 50%) or less, there is a high probability that the product life of the storage battery is at the end. In this way, the deterioration state of the storage battery can be estimated based on the value of SOH-P, i.e., the relationship between the reference characteristic value and the target characteristic value.
[変形例]
以上、本開示での様々な例を詳細に説明した。しかし、本開示は上記の例に限定されるものではない。本開示に関しては、その要旨を逸脱しない範囲で様々な変形が可能である。 [Modification]
Various examples of the present disclosure have been described in detail above. However, the present disclosure is not limited to the above examples. Various modifications of the present disclosure are possible without departing from the spirit and scope of the present disclosure.
以上、本開示での様々な例を詳細に説明した。しかし、本開示は上記の例に限定されるものではない。本開示に関しては、その要旨を逸脱しない範囲で様々な変形が可能である。 [Modification]
Various examples of the present disclosure have been described in detail above. However, the present disclosure is not limited to the above examples. Various modifications of the present disclosure are possible without departing from the spirit and scope of the present disclosure.
電池管理システム1は、ステップS2,S3において一度算出された基準特性値を繰り返し用いつつ、複数の対象期間のそれぞれについてステップS4~S6の処理を繰り返し実行してもよい。すなわち、算出部12は、複数の対象期間のそれぞれにおいて、対象特性値を算出し、基準特性値と該対象特性値との関係を算出してもよい。この場合に、算出部12は各対象期間において、算出された関係を重み付けパラメータに基づいて重み付けした上で、複数の対象期間における該関係の平均値を算出してもよい。この平均値は重み付き平均値であるともいえる。重み付けパラメータは、OCV-SOC特性における近似定数、DCR-SOC特性における近似定数、対象期間における総放電量、蓄電池への補水のタイミングとの時間間隔、および対象特性値の変化率のうち少なくとも一つを含む。対象特性値の変化率は、一つ前の対象期間における対象特性値からの変化率を示す。電池管理システム1はステップS7において、その重み付き平均値に基づいて蓄電池の劣化状態を推定してもよい。
The battery management system 1 may repeatedly execute the processes of steps S4 to S6 for each of the multiple target periods while repeatedly using the reference characteristic value calculated once in steps S2 and S3. That is, the calculation unit 12 may calculate the target characteristic value for each of the multiple target periods and calculate the relationship between the reference characteristic value and the target characteristic value. In this case, the calculation unit 12 may weight the calculated relationship for each target period based on a weighting parameter, and then calculate an average value of the relationship for the multiple target periods. This average value can also be said to be a weighted average value. The weighting parameter includes at least one of an approximate constant in the OCV-SOC characteristic, an approximate constant in the DCR-SOC characteristic, a total discharge amount in the target period, a time interval with respect to the timing of refilling the storage battery, and a rate of change of the target characteristic value. The rate of change of the target characteristic value indicates the rate of change from the target characteristic value in the previous target period. In step S7, the battery management system 1 may estimate the deterioration state of the storage battery based on the weighted average value.
一例では、一つの対象期間を1サイクルと見なして、一つの重み付き平均値を得るための複数の対象期間がnサイクルとして設定される。ただし、n>1である。この場合、nサイクルにおける基準特性値と対象特性値との関係の重み付き平均値が算出される。時間軸に沿って(n+1)以上の対象期間が設定される場合に、電池管理システム1は、連続するn個の対象期間の組合せを時間軸に沿ってずらしながら、基準特性値と対象特性値との関係の重み付き平均値を各組合せにおいて算出して、該関係の重み付き移動平均の時系列データを算出してもよい。電池管理システム1はステップS7において、その時系列データに基づいて蓄電池の劣化状態を推定してもよい。
In one example, one target period is regarded as one cycle, and multiple target periods for obtaining one weighted average value are set as n cycles, where n>1. In this case, a weighted average value of the relationship between the reference characteristic value and the target characteristic value in n cycles is calculated. When (n+1) or more target periods are set along the time axis, the battery management system 1 may calculate a weighted average value of the relationship between the reference characteristic value and the target characteristic value for each combination while shifting combinations of n consecutive target periods along the time axis, and calculate time series data of a weighted moving average of the relationship. In step S7, the battery management system 1 may estimate the degradation state of the storage battery based on the time series data.
推定部13は、基準特性値または対象特性値を算出する際に用いられたOCV-SOC特性の1以上の近似定数およびDCR-SOC特性の1以上の近似定数のうち少なくとも一つが所定の範囲外である場合には、それらの特性を用いて算出された基準特性値と対象特性値との関係を無効と判定してもよい。基準特性値および対象特性値との関係が無効である場合には、推定部13はその関係に基づいて蓄電池の劣化状態を推定しなくてもよい。
If at least one of the one or more approximation constants of the OCV-SOC characteristic and the one or more approximation constants of the DCR-SOC characteristic used in calculating the reference characteristic value or the target characteristic value is outside a predetermined range, the estimation unit 13 may determine that the relationship between the reference characteristic value calculated using those characteristics and the target characteristic value is invalid. If the relationship between the reference characteristic value and the target characteristic value is invalid, the estimation unit 13 may not need to estimate the degradation state of the storage battery based on that relationship.
さらに、基準特性値と対象特性値との関係が連続して所定回数以上無効と判定された場合には、推定部13は蓄電池の特性に急激な変化が生じたと推定してもよい。この場合、出力部14はその推定に基づいて、蓄電池の製品寿命が末期であることを示す情報を処理結果として出力してもよい。
Furthermore, if the relationship between the reference characteristic value and the target characteristic value is determined to be invalid a predetermined number of times in succession, the estimation unit 13 may estimate that a sudden change has occurred in the characteristics of the storage battery. In this case, the output unit 14 may output, as a processing result, information indicating that the product life of the storage battery is at the end, based on the estimation.
算出部12は統計的手法以外の方法によってOCV-SOC特性およびDCR-SOC特性を算出してもよい。例えば、算出部12は、測定データが得られる度に、カルマンフィルタを用いてOCV-SOC特性およびDCR-SOC特性を算出してもよい。
The calculation unit 12 may calculate the OCV-SOC characteristics and the DCR-SOC characteristics using a method other than a statistical method. For example, the calculation unit 12 may calculate the OCV-SOC characteristics and the DCR-SOC characteristics using a Kalman filter each time measurement data is obtained.
サーバ10とは異なるコンピュータまたは装置が基準特性値と対象特性値との関係を算出してもよい。例えば、個々のBMU3が、対応する蓄電池に関する基準特性値と対象特性値との関係を算出してもよい。すなわち電池管理システムはBMU3に実装されてもよい。
A computer or device other than the server 10 may calculate the relationship between the reference characteristic value and the target characteristic value. For example, each BMU 3 may calculate the relationship between the reference characteristic value and the target characteristic value for the corresponding storage battery. In other words, the battery management system may be implemented in the BMU 3.
BMU3は、測定電圧および測定電流の移動平均を算出し、これらの移動平均を示す蓄電池データをデータベース20に向けて送信してもよい。この場合には、BMU3とデータベース20との間の通信量を削減するとともに、サーバ10での処理負荷を低減できる。
The BMU 3 may calculate a moving average of the measured voltage and current, and transmit storage battery data indicating these moving averages to the database 20. In this case, the amount of communication between the BMU 3 and the database 20 can be reduced, and the processing load on the server 10 can be reduced.
少なくとも一つのプロセッサにより実行される電池管理方法は上記の例に限定されない。例えば、上述したステップまたは処理の一部が省略されてもよいし、別の順序で各ステップが実行されてもよい。また。上述したステップのうち任意の2以上のステップが組み合わされてもよいし、ステップの一部が修正または削除されてもよい。あるいは、上記の各ステップに加えて他のステップが実行されてもよい。
The battery management method executed by at least one processor is not limited to the above examples. For example, some of the steps or processes described above may be omitted, or the steps may be executed in a different order. Also, any two or more of the steps described above may be combined, or some of the steps may be modified or deleted. Alternatively, other steps may be executed in addition to the steps described above.
本開示において、「少なくとも一つのプロセッサが、第1の処理を実行し、第2の処理を実行し、…第nの処理を実行する。」との表現、またはこれに対応する表現は、第1の処理から第nの処理までのn個の処理を実行するプロセッサが途中で変わる場合を含む概念を示す。すなわち、この表現は、n個の処理のすべてが同じプロセッサで実行される場合と、n個の処理においてプロセッサが任意の方針で変わる場合との双方を含む概念を示す。
In this disclosure, the expression "at least one processor executes a first process, executes a second process, ... executes an nth process" or a corresponding expression indicates a concept including a case where the processor executing the n processes from the first process to the nth process changes midway. In other words, this expression indicates a concept including both a case where all n processes are executed by the same processor and a case where the processor changes among the n processes according to an arbitrary policy.
本開示における二つの数値の大小関係の比較では、「以上」および「よりも大きい」という二つの基準のどちらが用いられてもよく、「以下」および「未満」の二つの基準のうちのどちらが用いられてもよい。
In this disclosure, when comparing the magnitude relationship of two numerical values, either of the two criteria "greater than or equal to" and "greater than" may be used, or either of the two criteria "less than or equal to" and "less than" may be used.
[付記]
上記の様々な例から把握されるとおり、本開示は以下に示す態様を含む。
<項目1>
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得する取得部と、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出する算出部と、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定する推定部と、
を備える電池管理システム。
<項目2>
前記算出部が、
前記基準期間における、前記蓄電池の閉回路電圧が満充電時の電圧から前記最低駆動電圧に至るまでの放電時間を、前記基準特性値として算出し、
前記対象期間における前記放電時間を前記対象特性値として算出する、
項目1に記載の電池管理システム。
<項目3>
前記算出部が、前記基準特性値と前記対象特性値との比を前記関係として算出する、
項目1または項目2に記載の電池管理システム。
<項目4>
前記算出部が、
前記基準期間における、前記蓄電池の充電状態と前記蓄電池の開回路電圧との関係を示すOCV-SOC特性と、前記基準期間における、前記充電状態と前記蓄電池の直流抵抗との関係を示すDCR-SOC特性とを前記基準データに基づいて算出し、
前記最低駆動電圧に加えて、前記基準期間における前記OCV-SOC特性および前記DCR-SOC特性に基づいて、前記基準特性値を算出し、
前記対象期間における前記OCV-SOC特性と前記DCR-SOC特性とを前記対象データに基づいて算出し、
前記最低駆動電圧に加えて、前記対象期間における前記OCV-SOC特性および前記DCR-SOC特性に基づいて、前記対象特性値を算出する、
項目1~項目3のいずれか一つに記載の電池管理システム。
<項目5>
前記基準データおよび前記対象データのそれぞれで示される前記蓄電池の状態が、前記蓄電池の測定電圧および測定電流を少なくとも含み、
前記算出部が、
前記基準データに基づいて、前記基準期間における、前記測定電流、前記測定電圧、および前記充電状態の関係であるI-V特性を統計的手法により算出し、該I-V特性に基づいて、前記基準期間における前記OCV-SOC特性および前記DCR-SOC特性を取得し、
前記対象データに基づいて、前記対象期間における、前記測定電流、前記測定電圧、および前記充電状態の関係であるI-V特性を前記統計的手法により算出し、該I-V特性に基づいて、前記対象期間における前記OCV-SOC特性および前記DCR-SOC特性を取得する、
項目4に記載の電池管理システム。
<項目6>
少なくとも一つのプロセッサを備える電池管理システムにより実行される電池管理方法であって、
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出するステップと、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定するステップと、
を含む電池管理方法。
<項目7>
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出するステップと、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定するステップと、
をコンピュータに実行させる電池管理プログラム。 [Additional Notes]
As can be seen from the various examples above, the present disclosure includes the following aspects.
<Item 1>
an acquisition unit that acquires reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
a calculation unit that calculates a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculates a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
an estimation unit that estimates a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management system comprising:
<Item 2>
The calculation unit,
A discharge time during the reference period during which the closed circuit voltage of the storage battery decreases from a fully charged voltage to the minimum driving voltage is calculated as the reference characteristic value;
Calculating the discharge time during the target period as the target characteristic value;
2. The battery management system according toitem 1.
<Item 3>
The calculation unit calculates a ratio between the reference characteristic value and the target characteristic value as the relationship.
3. The battery management system according to claim 1 or 2.
<Item 4>
The calculation unit,
Calculating an OCV-SOC characteristic indicating a relationship between a state of charge of the storage battery and an open circuit voltage of the storage battery during the reference period, and a DCR-SOC characteristic indicating a relationship between the state of charge of the storage battery and a direct current resistance of the storage battery during the reference period, based on the reference data;
Calculating the reference characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period in addition to the minimum driving voltage;
Calculating the OCV-SOC characteristic and the DCR-SOC characteristic during the target period based on the target data;
Calculating the target characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic during the target period in addition to the minimum driving voltage;
4. The battery management system according toclaim 1,
<Item 5>
The state of the storage battery indicated by each of the reference data and the target data includes at least a measured voltage and a measured current of the storage battery;
The calculation unit,
Based on the reference data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the reference period is calculated by a statistical method, and based on the IV characteristic, the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period are obtained;
Based on the target data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the target period is calculated by the statistical method, and the OCV-SOC characteristic and the DCR-SOC characteristic during the target period are obtained based on the IV characteristic.
5. The battery management system according to item 4.
<Item 6>
1. A battery management method executed by a battery management system having at least one processor, comprising:
obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management method comprising:
<Item 7>
obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management program that causes a computer to execute the following.
上記の様々な例から把握されるとおり、本開示は以下に示す態様を含む。
<項目1>
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得する取得部と、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出する算出部と、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定する推定部と、
を備える電池管理システム。
<項目2>
前記算出部が、
前記基準期間における、前記蓄電池の閉回路電圧が満充電時の電圧から前記最低駆動電圧に至るまでの放電時間を、前記基準特性値として算出し、
前記対象期間における前記放電時間を前記対象特性値として算出する、
項目1に記載の電池管理システム。
<項目3>
前記算出部が、前記基準特性値と前記対象特性値との比を前記関係として算出する、
項目1または項目2に記載の電池管理システム。
<項目4>
前記算出部が、
前記基準期間における、前記蓄電池の充電状態と前記蓄電池の開回路電圧との関係を示すOCV-SOC特性と、前記基準期間における、前記充電状態と前記蓄電池の直流抵抗との関係を示すDCR-SOC特性とを前記基準データに基づいて算出し、
前記最低駆動電圧に加えて、前記基準期間における前記OCV-SOC特性および前記DCR-SOC特性に基づいて、前記基準特性値を算出し、
前記対象期間における前記OCV-SOC特性と前記DCR-SOC特性とを前記対象データに基づいて算出し、
前記最低駆動電圧に加えて、前記対象期間における前記OCV-SOC特性および前記DCR-SOC特性に基づいて、前記対象特性値を算出する、
項目1~項目3のいずれか一つに記載の電池管理システム。
<項目5>
前記基準データおよび前記対象データのそれぞれで示される前記蓄電池の状態が、前記蓄電池の測定電圧および測定電流を少なくとも含み、
前記算出部が、
前記基準データに基づいて、前記基準期間における、前記測定電流、前記測定電圧、および前記充電状態の関係であるI-V特性を統計的手法により算出し、該I-V特性に基づいて、前記基準期間における前記OCV-SOC特性および前記DCR-SOC特性を取得し、
前記対象データに基づいて、前記対象期間における、前記測定電流、前記測定電圧、および前記充電状態の関係であるI-V特性を前記統計的手法により算出し、該I-V特性に基づいて、前記対象期間における前記OCV-SOC特性および前記DCR-SOC特性を取得する、
項目4に記載の電池管理システム。
<項目6>
少なくとも一つのプロセッサを備える電池管理システムにより実行される電池管理方法であって、
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出するステップと、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定するステップと、
を含む電池管理方法。
<項目7>
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出するステップと、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定するステップと、
をコンピュータに実行させる電池管理プログラム。 [Additional Notes]
As can be seen from the various examples above, the present disclosure includes the following aspects.
<
an acquisition unit that acquires reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
a calculation unit that calculates a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculates a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
an estimation unit that estimates a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management system comprising:
<
The calculation unit,
A discharge time during the reference period during which the closed circuit voltage of the storage battery decreases from a fully charged voltage to the minimum driving voltage is calculated as the reference characteristic value;
Calculating the discharge time during the target period as the target characteristic value;
2. The battery management system according to
<
The calculation unit calculates a ratio between the reference characteristic value and the target characteristic value as the relationship.
3. The battery management system according to
<Item 4>
The calculation unit,
Calculating an OCV-SOC characteristic indicating a relationship between a state of charge of the storage battery and an open circuit voltage of the storage battery during the reference period, and a DCR-SOC characteristic indicating a relationship between the state of charge of the storage battery and a direct current resistance of the storage battery during the reference period, based on the reference data;
Calculating the reference characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period in addition to the minimum driving voltage;
Calculating the OCV-SOC characteristic and the DCR-SOC characteristic during the target period based on the target data;
Calculating the target characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic during the target period in addition to the minimum driving voltage;
4. The battery management system according to
<Item 5>
The state of the storage battery indicated by each of the reference data and the target data includes at least a measured voltage and a measured current of the storage battery;
The calculation unit,
Based on the reference data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the reference period is calculated by a statistical method, and based on the IV characteristic, the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period are obtained;
Based on the target data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the target period is calculated by the statistical method, and the OCV-SOC characteristic and the DCR-SOC characteristic during the target period are obtained based on the IV characteristic.
5. The battery management system according to item 4.
<Item 6>
1. A battery management method executed by a battery management system having at least one processor, comprising:
obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management method comprising:
<Item 7>
obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management program that causes a computer to execute the following.
項目1,6,7によれば、基準データおよび最低駆動電圧に基づいて算出された基準特性値と対象データおよび最低駆動電圧に基づいて算出された対象特性値との関係から、蓄電池の劣化状態が推定される。蓄電池から電力が供給される電動機器のパラメータである最低駆動電圧を考慮することで、該蓄電池の実使用に即した基準特性値および対象特性値を算出することができる。したがって、これら二つの特性値の関係に基づいて、蓄電池の劣化状態を正確に推定することができる。
According to items 1, 6, and 7, the degraded state of the storage battery is estimated from the relationship between the reference characteristic value calculated based on the reference data and the minimum driving voltage and the target characteristic value calculated based on the target data and the minimum driving voltage. By taking into account the minimum driving voltage, which is a parameter of the electrically-driven device to which power is supplied from the storage battery, it is possible to calculate the reference characteristic value and the target characteristic value that are in line with the actual use of the storage battery. Therefore, the degraded state of the storage battery can be accurately estimated based on the relationship between these two characteristic values.
蓄電池の閉回路電圧が満充電時の電圧から最低駆動電圧に至るまでの放電時間は、蓄電池の劣化の状態を顕著に表す。したがって、項目2によれば、その放電時間を特性値として用いることで、蓄電池の劣化状態をより一層正確に推定することができる。
The discharge time it takes for the closed circuit voltage of a storage battery to drop from the fully charged voltage to the minimum operating voltage clearly indicates the deterioration state of the storage battery. Therefore, according to item 2, by using the discharge time as a characteristic value, the deterioration state of the storage battery can be estimated more accurately.
項目3によれば、基準特性値と対象特性値との比を両特性値の関係として採用することで、蓄電池の劣化状態をより一層明確に推定することができる。
According to item 3, by using the ratio between the reference characteristic value and the target characteristic value as the relationship between the two characteristic values, the deterioration state of the storage battery can be estimated more clearly.
項目4によれば、特性値を算出するにあたって基準期間および対象期間におけるOCV-SOC特性およびDCR-SOC特性を用いることで、基準特性値および対象特性値を正確に算出することができる。
According to item 4, by using the OCV-SOC characteristics and DCR-SOC characteristics in the reference period and the target period to calculate the characteristic values, the reference characteristic value and the target characteristic value can be accurately calculated.
項目5によれば、統計的手法を用いてOCV-SOC特性およびDCR-SOC特性を取得することで、蓄電池の測定値から精度良くこれらの特性を取得できる。精度良く取得されたOCV-SOC特性およびDCR-SOC特性を特性値の算出に用いることで、基準期間および対象期間における特性値の算出と蓄電池の劣化状態との双方についての精度の向上が期待できる。
According to item 5, by using statistical methods to obtain the OCV-SOC characteristics and DCR-SOC characteristics, these characteristics can be obtained with high accuracy from the measured values of the storage battery. By using the accurately obtained OCV-SOC characteristics and DCR-SOC characteristics to calculate the characteristic values, it is expected that the accuracy of both the calculation of the characteristic values and the deterioration state of the storage battery during the reference period and the target period can be improved.
1…電池管理システム、2…電動機器、11…取得部、12…算出部、13…推定部、14…出力部。
1: Battery management system, 2: Electric device, 11: Acquisition unit, 12: Calculation unit, 13: Estimation unit, 14: Output unit.
Claims (7)
- 基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得する取得部と、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出する算出部と、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定する推定部と、
を備える電池管理システム。 an acquisition unit that acquires reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
a calculation unit that calculates a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculates a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
an estimation unit that estimates a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management system comprising: - 前記算出部が、
前記基準期間における、前記蓄電池の閉回路電圧が満充電時の電圧から前記最低駆動電圧に至るまでの放電時間を、前記基準特性値として算出し、
前記対象期間における前記放電時間を前記対象特性値として算出する、
請求項1に記載の電池管理システム。 The calculation unit,
A discharge time during the reference period during which the closed circuit voltage of the storage battery decreases from a fully charged voltage to the minimum driving voltage is calculated as the reference characteristic value;
Calculating the discharge time during the target period as the target characteristic value;
The battery management system of claim 1 . - 前記算出部が、前記基準特性値と前記対象特性値との比を前記関係として算出する、
請求項1または2に記載の電池管理システム。 The calculation unit calculates a ratio between the reference characteristic value and the target characteristic value as the relationship.
The battery management system according to claim 1 . - 前記算出部が、
前記基準期間における、前記蓄電池の充電状態と前記蓄電池の開回路電圧との関係を示すOCV-SOC特性と、前記基準期間における、前記充電状態と前記蓄電池の直流抵抗との関係を示すDCR-SOC特性とを前記基準データに基づいて算出し、
前記最低駆動電圧に加えて、前記基準期間における前記OCV-SOC特性および前記DCR-SOC特性に基づいて、前記基準特性値を算出し、
前記対象期間における前記OCV-SOC特性と前記DCR-SOC特性とを前記対象データに基づいて算出し、
前記最低駆動電圧に加えて、前記対象期間における前記OCV-SOC特性および前記DCR-SOC特性に基づいて、前記対象特性値を算出する、
請求項1または2に記載の電池管理システム。 The calculation unit,
Calculating an OCV-SOC characteristic indicating a relationship between a state of charge of the storage battery and an open circuit voltage of the storage battery during the reference period, and a DCR-SOC characteristic indicating a relationship between the state of charge of the storage battery and a direct current resistance of the storage battery during the reference period, based on the reference data;
Calculating the reference characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period in addition to the minimum driving voltage;
Calculating the OCV-SOC characteristic and the DCR-SOC characteristic during the target period based on the target data;
Calculating the target characteristic value based on the OCV-SOC characteristic and the DCR-SOC characteristic during the target period in addition to the minimum driving voltage;
The battery management system according to claim 1 . - 前記基準データおよび前記対象データのそれぞれで示される前記蓄電池の状態が、前記蓄電池の測定電圧および測定電流を少なくとも含み、
前記算出部が、
前記基準データに基づいて、前記基準期間における、前記測定電流、前記測定電圧、および前記充電状態の関係であるI-V特性を統計的手法により算出し、該I-V特性に基づいて、前記基準期間における前記OCV-SOC特性および前記DCR-SOC特性を取得し、
前記対象データに基づいて、前記対象期間における、前記測定電流、前記測定電圧、および前記充電状態の関係であるI-V特性を前記統計的手法により算出し、該I-V特性に基づいて、前記対象期間における前記OCV-SOC特性および前記DCR-SOC特性を取得する、
請求項4に記載の電池管理システム。 The state of the storage battery indicated by each of the reference data and the target data includes at least a measured voltage and a measured current of the storage battery;
The calculation unit,
Based on the reference data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the reference period is calculated by a statistical method, and based on the IV characteristic, the OCV-SOC characteristic and the DCR-SOC characteristic during the reference period are obtained;
Based on the target data, an IV characteristic which is a relationship between the measured current, the measured voltage, and the state of charge during the target period is calculated by the statistical method, and the OCV-SOC characteristic and the DCR-SOC characteristic during the target period are obtained based on the IV characteristic.
The battery management system according to claim 4. - 少なくとも一つのプロセッサを備える電池管理システムにより実行される電池管理方法であって、
基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出するステップと、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定するステップと、
を含む電池管理方法。 1. A battery management method executed by a battery management system having at least one processor, comprising:
obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management method comprising: - 基準期間における蓄電池の状態を示す基準データと、該基準期間より後の対象期間における該蓄電池の状態を示す対象データとを取得するステップと、
前記基準データと、前記蓄電池から供給される電力を用いる電動機器の最低駆動電圧とに基づいて、前記基準期間における前記蓄電池の放電に関する特性値を基準特性値として算出し、前記対象データと前記最低駆動電圧とに基づいて、前記対象期間における前記蓄電池の放電に関する特性値を対象特性値として算出するステップと、
前記基準特性値と前記対象特性値との関係に基づいて、前記蓄電池の劣化状態を推定するステップと、
をコンピュータに実行させる電池管理プログラム。 obtaining reference data indicating a state of the storage battery in a reference period and target data indicating a state of the storage battery in a target period after the reference period;
calculating a characteristic value related to the discharge of the storage battery during the reference period as a reference characteristic value based on the reference data and a minimum driving voltage of an electrically-driven device that uses power supplied from the storage battery, and calculating a characteristic value related to the discharge of the storage battery during the target period as a target characteristic value based on the target data and the minimum driving voltage;
estimating a degradation state of the storage battery based on a relationship between the reference characteristic value and the target characteristic value;
A battery management program that causes a computer to execute the following:
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