Correction method, computer program, correction device, and power storage device

Abstract

To provide a correction method capable of improving correction accuracy of the amount of charged electricity in a power storage device.SOLUTION: A correction method determines whether or not the difference between a terminal voltage value at the time of energization of a power storage device and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or larger than a first threshold value. In the correction method, when it is determined that the difference is equal to or larger than the first threshold value, a computer executes processing of correcting an estimation value of the amount of charged electricity in the power storage device based on the amount of change in an open voltage value of the power storage device obtained from the equivalent circuit model and according to a predetermined amount of change of the amount of charged electricity in the power storage device.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a correction method, a computer program, a correction device, and an electricity storage device. [Background technology]

[0002] BACKGROUND ART The OCV method and the current integration method are commonly used methods for estimating the state of charge (SOC) of a power storage element such as a secondary battery mounted on a vehicle.

[0003] The OCV method uses the one-to-one correlation (SOC-OCV characteristics) between the open circuit voltage (OCV) of a storage element and the SOC to estimate the SOC from the voltage value of the storage element obtained by a voltage sensor.The current integration method measures the charge / discharge current value of the storage element at specified time intervals using a current sensor, and estimates the SOC by adding or subtracting the measured current value from the initial value.

[0004] When current integration is continued for a long period of time, measurement errors in the current sensor accumulate, causing the estimation error by the current integration method to increase over time. Conventionally, an OCV reset is performed to correct the SOC obtained by the current integration method using the SOC obtained by the OCV method.

[0005] Patent Document 1 discloses an SOC management device that can prevent a decrease in the accuracy of correcting the SOC of a battery when an OCV is reset. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-12106 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional SOC management devices do not provide sufficient accuracy in correcting the state of charge.

[0008] An object of the present disclosure is to provide a correction method and the like that can improve the correction accuracy of the amount of electricity charged in an electricity storage device. [Means for solving the problem]

[0009] A correction method according to one aspect of the present disclosure determines whether a difference between a terminal voltage value of a power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold. If it is determined that the difference is equal to or greater than the first threshold, the correction method causes a computer to execute a process of correcting the estimated value of the amount of electricity charged in the power storage device based on an amount of change in an open-circuit voltage value of the power storage device that corresponds to a predetermined amount of change in the amount of electricity charged in the power storage device, the amount of change being obtained from the equivalent circuit model. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to improve the accuracy of correcting the amount of electricity charged in an electricity storage device. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an example of the configuration of an electricity storage device in which a management device according to a first embodiment is mounted. [Figure 2] FIG. 2 is an exploded perspective view showing a configuration example of an electricity storage device. [Figure 3] FIG. 2 is a block diagram showing a configuration example of a management device, etc. [Figure 4] FIG. 2 is a circuit diagram illustrating an example of an equivalent circuit model of the power storage device. [Figure 5] FIG. 10 is an explanatory diagram illustrating a method for correcting an SOC. [Figure 6] FIG. 10 is an explanatory diagram illustrating a method for correcting an SOC. [Figure 7] FIG. 10 is an explanatory diagram illustrating a method for correcting an SOC. [Figure 8] FIG. 10 is an explanatory diagram illustrating a method for correcting an SOC. [Figure 9] 10 is a flowchart showing an example of a procedure for correcting the amount of charged electricity. [Figure 10] 10 is a flowchart showing an example of a procedure for correcting the amount of charged electricity. [Figure 11] FIG. 10 is an explanatory diagram illustrating the concept of correction termination based on an apparent SOC value. [Figure 12] 10 is a flowchart showing an example of a correction end processing procedure in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The correction method determines whether a difference between a terminal voltage value of a power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold. If it is determined that the difference is equal to or greater than the first threshold, the correction method causes a computer to execute a process of correcting the estimated value of the amount of electricity charged in the power storage device based on a change in an open-circuit voltage value of the power storage device corresponding to a predetermined change in the amount of electricity charged in the power storage device, which change is obtained from the equivalent circuit model.

[0013] The correction method corrects the estimated value of the amount of electricity charged in the power storage device when it is determined that the difference (absolute difference) between the terminal voltage value of the power storage device when power is applied and the estimated voltage value estimated using an equivalent circuit model of the power storage device is greater than or equal to a first threshold value.

[0014] The charged amount of electricity may be, for example, the SOC, which is expressed as the ratio of the remaining capacity to the fully charged capacity of the storage element. The terminal voltage value of the power storage device is, for example, a voltage value of the power storage device acquired by a voltage sensor. The estimated value of the charged amount of electricity in the power storage device may be an estimated value of the SOC using a current integration method. The current integration method is a method in which a current sensor measures the charging / discharging current of a power storage element at predetermined time intervals, the measured current values ​​are integrated to calculate the amount of power flowing in and out of the power storage element, and the SOC is estimated by adding or subtracting the calculated amount of power from the initial full charge capacity. The open circuit voltage (OCV) refers to the voltage value when the amount of current flowing through the storage element is zero and there is no influence of polarization, and also includes the voltage value of the storage element when the amount of current flowing through the storage element is below a threshold value and when the amount of current flowing through the storage element is as small as a dark current.

[0015] Conventionally, OCV reset is performed to correct the SOC calculated by the current integration method described above to an SOC estimated using the relationship between the charged amount of electricity and the open circuit voltage value of the power storage device (SOC-OCV characteristics). In the OCV method, the SOC corresponding to the OCV of the power storage device is estimated from the SOC-OCV characteristics based on the voltage value of the power storage device obtained by a voltage sensor.

[0016] The present inventors have focused on the following points when using, as an electricity storage device, an electricity storage element (secondary battery) having an electrode body containing lithium iron phosphate, lithium manganese oxide, or the like as a positive electrode active material. The secondary battery has a plateau region in its SOC-OCV characteristics where the OCV barely changes with changes in the SOC over a wide range. That is, there is almost no voltage difference between the part of the electrode where the charge / discharge reaction has progressed and the part where the charge / discharge reaction has not progressed. Therefore, when the power storage device is charged / discharged, SOC unevenness (SOC bias) occurs in which the SOC is high or low in only one part of the electrode.

[0017] When SOC unevenness occurs, the effective battery capacity of the power storage device temporarily drops below its actual battery capacity. When battery capacity temporarily drops, for example, during discharge, the battery voltage drops earlier than predicted based on the actual battery capacity. When SOC unevenness occurs in a power storage device used in a vehicle, the actual terminal voltage drops below the predicted voltage, which can reduce the voltage supplied to the vehicle and potentially degrade the performance of the electric power steering, electric brakes, and other components. This type of temporary deterioration (decrease) in charge / discharge performance due to SOC unevenness is particularly pronounced during high-current charge / discharge under low-temperature conditions. When the above-mentioned temporary phenomenon occurs, the correlation between SOC and OCV is no longer valid, and performing a normal OCV reset results in a large SOC estimation error.

[0018] This correction method corrects the estimated SOC based on the amount of change in the open circuit voltage (OCV) of the power storage device, which corresponds to a predetermined amount of change in the amount of charge (e.g., SOC) of the power storage device, obtained from an equivalent circuit model of the power storage device. This makes it possible to correct the SOC while taking into account voltage fluctuations due to temporary phenomena. Even when temporary phenomena occur, the SOC can be corrected with high accuracy.

[0019] The presence or absence of a temporary phenomenon, i.e., the need for correction, is determined based on whether the difference between the terminal voltage value when the power storage device is energized and the estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold. Whether correction is necessary can be efficiently determined based on the difference between the actually measured data of the terminal voltage value and the estimated voltage value that can be easily calculated using the equivalent circuit model.

[0020] This makes it possible to predict the short-term voltage and power characteristics of the energy storage device, estimating its State of Function (SOF), even during charging and discharging. For example, in response to a query from a higher-level control device such as "What is the maximum current value at which the voltage will not fall below the target voltage after a certain period of time?", the energy storage device management device (e.g., battery management unit) can respond appropriately using a corrected SOC that takes into account SOC changes due to temporary phenomena.

[0021] The correction method may identify a region of the charging quantity of electricity that satisfies a correspondence relationship between a predetermined amount of change in the charging quantity of electricity and an amount of change in the open-circuit voltage value in a profile showing the relationship between the charging quantity of electricity and the open-circuit voltage value of the energy storage device, and correct the estimated value of the charging quantity of electricity based on the identified region of the charging quantity of electricity.

[0022] According to the above configuration, the estimated SOC can be efficiently corrected using a profile (SOC-OCV characteristics) that indicates the relationship between the amount of charge and the open-circuit voltage of the power storage device. Based on the amount of change in the open-circuit voltage caused by a temporary change in the SOC, the SOC can be suitably corrected by identifying the SOC range corresponding to the amount of change in the open-circuit voltage using the known SOC-OCV characteristics.

[0023] The correction method may calculate the change in the open-circuit voltage value by subtracting the difference in polarization voltage values ​​associated with the equivalent circuit model at the first and second time points from the difference in the terminal voltage values ​​at the first and second time points, where the difference is equal to or greater than a first threshold value.

[0024] According to the above configuration, the amount of change in the open circuit voltage value relative to the amount of change in the terminal voltage value can be calculated easily and accurately based on actual measurement data from an actual battery test or the like.

[0025] The correction method may determine whether the terminal voltage value and the estimated voltage value intersect based on the current history of the storage device, and if it is determined that the terminal voltage value and the estimated voltage value intersect, correct the estimated value of the charged amount of electricity.

[0026] According to the above configuration, the occurrence of the above-mentioned temporary phenomenon is detected by determining whether or not the terminal voltage value and the estimated voltage value intersect. By setting the timing of the occurrence of this phenomenon as the timing to start correction, correction can be started promptly in response to the occurrence of the phenomenon, thereby further improving estimation accuracy.

[0027] The correction method may further include, when the difference between the terminal voltage value and the estimated voltage value after the correction of the charged amount of electricity is equal to or greater than a second threshold, re-correcting the estimated value of the charged amount of electricity by sequentially adding or subtracting a predetermined value to the corrected charged amount of electricity.

[0028] According to the above configuration, if the difference (absolute difference) between the corrected terminal voltage and the estimated voltage value is equal to or greater than the second threshold, the corrected SOC is re-corrected (adjusted), thereby reducing estimation error or measurement error and further improving estimation accuracy.

[0029] The correction method may be such that, when the corrected amount of charged electricity becomes equal to or greater than a third threshold, correction of the estimated value of the amount of charged electricity is terminated and the estimated value of the amount of charged electricity is restored to the value before correction.

[0030] According to the above configuration, the present correction method is executed only when it is estimated that there is an influence of a temporary phenomenon. By limiting the correction method to an SOC range where it is estimated that there is no influence of the phenomenon, the SOC change due to the phenomenon can be appropriately reflected and the estimated SOC value can be appropriately corrected.

[0031] The computer program determines whether a difference between a terminal voltage value of a power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold. If the computer program determines that the difference is equal to or greater than the first threshold, the computer program causes the computer to execute a process of correcting the estimated value of the amount of electricity charged in the power storage device based on an amount of change in an open-circuit voltage value of the power storage device that corresponds to a predetermined amount of change in the amount of electricity charged in the power storage device, the amount of change being obtained from the equivalent circuit model.

[0032] The correction device includes a control unit that executes control related to correction of an estimated value of the amount of electricity charged in the power storage device. The control unit determines whether a difference between a terminal voltage value of the power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold. If the control unit determines that the difference is equal to or greater than the first threshold, it corrects the estimated value of the amount of electricity charged in the power storage device based on a change in an open-circuit voltage value of the power storage device corresponding to a predetermined change in the amount of electricity charged in the power storage device, which is obtained from the equivalent circuit model.

[0033] The power storage device includes a power storage element and the above-described correction device.

[0034] Hereinafter, the present disclosure will be specifically described with reference to the drawings showing embodiments thereof.

[0035] (First embodiment) Fig. 1 is a perspective view showing a configuration example of an electricity storage device 1 on which a management device according to a first embodiment is mounted, and Fig. 2 is an exploded perspective view showing the configuration example of the electricity storage device 1. The electricity storage device 1 is a 12V or 48V power supply that is suitably mounted on, for example, an engine vehicle, an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), etc.

[0036] The energy storage device 1 has a management device (correction device) 2 and a rectangular parallelepiped storage case 4a that stores a plurality of energy storage elements 3. The energy storage elements 3 may be battery cells such as lithium-ion secondary batteries. The management device 2 is, for example, a battery management system (BMS). The storage case 4a also stores a plurality of bus bars 5, various sensors (see FIG. 3), and the like. In FIGS. 1 and 2, the energy storage elements 3 are stored in the storage case 4a in the form of an assembled battery 30, with four elements connected in series.

[0037] The storage case 4a is made of synthetic resin. The storage case 4a includes a case body 41, a lid 42 that closes the opening of the case body 41, a storage section 43 provided on the outer surface of the lid 42, a cover 44 that covers the storage section 43, an inner lid 45, and a partition plate 46. The inner lid 45 and the partition plate 46 do not necessarily have to be provided. The energy storage element 3 is inserted between the partition plates 46 of the case body 41.

[0038] A plurality of metal bus bars 5 are placed on inner lid 45. Inner lid 45 is placed near the terminal surface on which terminals 32 of energy storage elements 3 are provided, and adjacent terminals 32 of adjacent energy storage elements 3 are connected by bus bars 5, so that the energy storage elements 3 are connected in series.

[0039] The storage section 43 is box-shaped and has a protrusion 43a that protrudes outward from the center of one long side surface in a plan view. A pair of external terminals 6, 6 made of metal such as a lead alloy and having opposite polarities are provided on both sides of the protrusion 43a on the lid section 42. The storage section 43 stores a management device 2 that is a flat circuit board. The management device 2 is connected to the energy storage elements 3 via conductors (not shown). The management device 2 manages the states of the multiple energy storage elements 3 and controls each part of the energy storage device 1.

[0040] The energy storage element 3 is a battery cell having the plateau region described above, such as an LFP battery. The energy storage element 3 includes a hollow rectangular parallelepiped case 31 and a pair of terminals 32, 32 with opposite polarities provided on one side (terminal surface) of the case 31. The case 31 contains an electrode assembly 33 formed by stacking a positive electrode 33a, a separator 33b, and a negative electrode 33c, as well as an electrolyte (electrolytic solution) (not shown).

[0041] The electrode assembly 33 is constructed by stacking a sheet-shaped positive electrode 33a and a sheet-shaped negative electrode 33c with two sheet-shaped separators 33b in between and winding them (longitudinal or transverse). The separators 33b are formed from a porous resin film. Examples of the porous resin film that can be used include porous resin films made of resins such as polyethylene (PE) and polypropylene (PP).

[0042] The positive electrode 33a is an electrode plate in which a positive electrode active material layer is formed on the surface of a long strip-shaped positive electrode substrate made of, for example, aluminum or an aluminum alloy. The positive electrode active material layer contains a positive electrode active material. The positive electrode active material used in the positive electrode active material layer can be a material capable of absorbing and releasing lithium ions. An example of the positive electrode active material is LiFePO4. The positive electrode active material layer may further contain a conductive additive, a binder, etc.

[0043] The negative electrode 33c is an electrode plate in which a negative electrode active material layer is formed on the surface of a long strip-shaped negative electrode substrate made of, for example, copper or a copper alloy. The negative electrode active material layer contains a negative electrode active material. The negative electrode active material can be a material capable of absorbing and releasing lithium ions. Examples of the negative electrode active material include graphite, hard carbon, and soft carbon. The negative electrode active material layer may further contain a binder, a thickener, and the like.

[0044] The electrolyte enclosed in the case 31 can be the same as that used in conventional lithium-ion secondary batteries. For example, an electrolyte containing a supporting salt in an organic solvent can be used. As the organic solvent, for example, an aprotic solvent such as carbonates, esters, or ethers can be used. As the supporting salt, for example, a lithium salt such as LiPF6, LiBF4, or LiClO4 can be suitably used. The electrolyte may contain various additives such as a gas generating agent, a film-forming agent, a dispersant, or a thickener.

[0045] 1 and 2, a prismatic lithium ion battery including a wound electrode assembly 33 has been described as an example of the energy storage element 3. Alternatively, the energy storage element 3 may be a cylindrical lithium ion battery. The energy storage element 3 may be a lithium ion battery including a stacked electrode assembly, or may be a laminated (pouch) lithium ion battery or the like. Furthermore, the energy storage element 3 may be an all-solid-state lithium ion battery using a solid electrolyte.

[0046] 3 is a block diagram showing an example of the configuration of the management device 2, etc. The management device 2 acquires measurement data including the voltage value and current value of the power storage device 1, and executes processing related to correction (estimation) of the amount of electricity charged in the power storage device 1 based on the acquired measurement data. The management device 2 corresponds to a correction device.

[0047] The power storage device 1 equipped with the management device 2 is connected to a vehicle ECU (Electronic Control Unit) 8 and a load 9 such as a starter motor for starting the engine and electrical components. When the starter motor functions as a generator, the power storage device 1 is charged by power (regenerative power) supplied from the starter motor. When the starter motor functions as a power source, the power storage device 1 supplies power to the starter motor and other electronic devices.

[0048] The management device 2 includes a control unit 21, a storage unit 22, an input unit 23, an output unit 24, and the like.

[0049] The control unit 21 is an arithmetic circuit including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The CPU included in the control unit 21 executes various computer programs stored in the ROM and the storage unit 22, and controls the operation of each of the hardware components described above, thereby causing the entire device to function as the management device (correction device) of the present disclosure. The control unit 21 may also include functions such as a timer that measures the elapsed time from when an instruction to start measurement is given until when an instruction to end measurement is given, a counter that counts numbers, and a clock that outputs date and time information.

[0050] The storage unit 22 is a non-volatile storage device such as a flash memory. Various computer programs and data are stored in the storage unit 22. The computer programs (computer program products) stored in the storage unit 22 include a correction program 221 for performing processing related to correction of the amount of electricity charged in the power storage device 1. The data stored in the storage unit 22 includes correction data 222 used in the correction program 221.

[0051] The correction data 222 includes information such as an equivalent circuit model of the power storage device 1 used in the simulation, SOC-OCV characteristics corresponding to the power storage device 1, and various thresholds used in the correction process. The equivalent circuit model is described by configuration information indicating the circuit configuration and values ​​of each element constituting the equivalent circuit model. The storage unit 22 stores configuration information indicating the circuit configuration of such an equivalent circuit model and values ​​of each element constituting the equivalent circuit model. The control unit 21 acquires information on the equivalent circuit model, SOC-OCV characteristics, and various thresholds in advance, for example, by communicating with an external device (not shown), and stores the acquired information in the correction data 222. The SOC-OCV characteristics may be updated at predetermined time intervals, taking into account deterioration that occurs with use of the power storage device 1.

[0052] The computer program stored in the storage unit 22 may be provided by a non-transitory recording medium 2A on which the computer program is readably recorded. The recording medium 2A is a portable memory such as a CD-ROM, a USB memory, or an SD (Secure Digital) card. The control unit 21 reads the desired computer program from the recording medium 2A using a reading device (not shown) and stores the read computer program in the storage unit 22. Alternatively, the computer program may be provided via communication. The correction program 221 can be deployed to be executed on a single computer, or on multiple computers located at one site, or distributed across multiple sites and interconnected by a communication network.

[0053] The input unit 23 has an interface for connecting various sensors. The sensors connected to the input unit 23 include a voltage sensor 7a that measures the voltage of the energy storage element 3 and a current sensor 7b that measures the current flowing through the energy storage element 3. The input unit 23 receives input of signals related to the measurement values ​​measured by the various sensors. The sensors connected to the input unit 23 may include a temperature sensor that measures the temperature of the energy storage element 3.

[0054] The voltage sensor 7a is connected in parallel to each storage element 3. The voltage sensor 7a is connected to both ends of each storage element 3, respectively, and measures the terminal voltage of each storage element 3 in a time series manner. The control unit 21 acquires data on the voltage of each storage element 3 and the total voltage of the battery pack 30 measured by the voltage sensor 7a via the input unit 23 at any time. The current sensor 7b is connected in series to the storage elements 3 and measures the current flowing through the storage elements 3 in a time series manner. The control unit 21 acquires data on the current measured by the current sensor 7b via the input unit 23 at any time.

[0055] The output unit 24 includes an interface for connecting a display device (not shown). An example of the display device is a liquid crystal display device. When the control unit 21 obtains information related to the amount of electricity charged in the power storage device 1, the control unit 21 outputs the information related to the amount of electricity charged in the power storage device 1 from the output unit 24 to the display device. The display device displays the information related to the amount of electricity charged based on the information output from the output unit 24.

[0056] Alternatively, the output unit 24 may include a communication interface for communicating with an external device (not shown). The external device communicatively connected to the output unit 24 is a terminal device such as a personal computer or smartphone used by a user, an administrator, or the like. The control unit 21 outputs information related to the amount of electricity charged in the power storage device 1 to the external device from the output unit 24. The output unit 24 may include a communication interface for communicating with the vehicle ECU 8. The control unit 21 outputs information related to the amount of electricity charged in the power storage device 1 to the vehicle ECU from the output unit 24. The management device 2 may include an alert unit such as an LED lamp or a buzzer to alert the user of information related to the amount of electricity charged in the power storage device 1.

[0057] 1 to 3 show an example in which the management device 2 is a BMS. Alternatively, the management device 2 may be located at a location remote from the energy storage elements 3. The management device 2 may include a server device or an ECU that is located at a location remote from the energy storage elements 3 and is communicatively connected to the BMS. The location where the amount of electricity charged in the energy storage device 1 is corrected is not limited, and may be the server device or the ECU, for example. In this case, measurement data measured regarding the energy storage device 1 may be transmitted to the server device or the ECU via communication.

[0058] 1 to 3 show an in-vehicle low-voltage power supply including an electric storage element 3 that is a lithium ion secondary battery as an electric storage device 1. The electric storage element 3 may be another secondary battery or electrochemical cell that has a plateau region.

[0059] 4 is a circuit diagram showing an example of an equivalent circuit model of the power storage device 1. The equivalent circuit model combines circuit elements such as a voltage source of the power storage device 1 and resistors and capacitors to simulate the charge and discharge behavior of the power storage device 1. The equivalent circuit model includes a constant voltage source connected in series between the positive electrode terminal and the negative electrode terminal, a DC resistor for simulating a DC resistance component, and an RC parallel circuit for simulating transient polarization characteristics. In the equivalent circuit model according to this embodiment, two RC parallel circuits, a first RC parallel circuit and a second RC parallel circuit, are connected in series.

[0060] The constant voltage source is a voltage source that outputs a DC voltage. The voltage output by the constant voltage source is the open-circuit voltage of the power storage device 1 and is denoted as Vo. The open-circuit voltage value Vo is given as a function of the SOC, for example. The open-circuit voltage value Vo may also be given as a function of the actual capacity of the power storage device 1.

[0061] The DC resistor is used to simulate the DC resistance component (DC impedance) of the power storage device 1, and includes a resistance element R0. The resistance element R0 is given as a value that varies depending on the current flow, voltage, SOC, temperature, etc. Once the impedance of the DC resistor is determined, it is possible to calculate the voltage generated in the DC resistor when a current I flows through this equivalent circuit model. The voltage generated in the DC resistor is defined as the DC resistance voltage value Vz0.

[0062] The first RC parallel circuit is composed of a resistive element R1 and a capacitive element C1 connected in parallel. The second RC parallel circuit is composed of a resistive element R2 and a capacitive element C2 connected in parallel. The resistive elements R1 and R2 and the capacitive elements C1 and C2 constituting each RC parallel circuit are given values ​​that vary depending on the SOC, temperature, etc. of the power storage device 1. The resistive elements R1 and R2 and the capacitive elements C1 and C2 determine the impedance of the RC parallel circuit. Once the impedance of the RC parallel circuit is determined, it is possible to calculate the voltage generated in the RC parallel circuit when a current I flows through this equivalent circuit model. The voltage generated in the RC parallel circuit is the sum of the polarization voltage value Vz1 generated in the first RC parallel circuit and the polarization voltage value Vz2 generated in the second RC parallel circuit.

[0063] In the above equivalent circuit model, the estimated value (estimated voltage value) Ve(t) of the terminal voltage at the time t has elapsed since the start of the simulation can be expressed by the following equation (1) using the DC resistance voltage value Vz0(t), polarization voltage value Vz1(t), polarization voltage value Vz2(t), and open circuit voltage value Vo(t). Ve(t)=Vo(t)+Vz0(t)+(Vz1(t)+Vz2(t))…(1)

[0064] The resistive element R0, resistive elements R1, R2, and capacitive elements C1, C2 (hereinafter also referred to as circuit parameters) that make up the above-mentioned equivalent circuit model can be obtained by known methods. The circuit parameters can be set, for example, based on actual measurement data from a battery test, taking into account the relationship between temperature, SOC, etc. The estimated voltage value Ve of the storage element 3 can be calculated using the open-circuit voltage value of the storage element 3 and the known circuit parameters.

[0065] The management device 2 in this embodiment estimates the SOC of the power storage device 1 at appropriate intervals using a current integration method and stores the estimated value in the storage unit 22. Specifically, the management device 2 calculates the amount of power flowing in and out of the power storage device 1 by integrating current values ​​acquired via the current sensor 7b. The management device 2 calculates an estimated value of the SOC of the power storage device 1 at the time of estimation by adding or subtracting the calculated amount of power to the full charge capacity at the reference time (initial). Alternatively, the management device 2 may acquire an estimated value of the SOC calculated by an external device (not shown) via communication.

[0066] The management device 2 determines whether or not the above-described temporary phenomenon occurs in the power storage device 1 in parallel with estimating the SOC using the current integration method. If this phenomenon occurs, the management device 2 corrects the SOC estimated by current integration using the following correction method. FIGS. 5 to 8 are explanatory diagrams illustrating the SOC correction method. The SOC correction method in this embodiment will be described using FIGS. 5 to 8, taking discharging as an example.

[0067] The graph shown in the upper part of FIG. 5 shows the change over time in the terminal voltage value Vb and the estimated voltage value Ve of the power storage device 1. In the graph shown in the upper part of FIG. 5, the vertical axis represents the terminal voltage (V) and the horizontal axis represents the elapsed time (s). The graph shown in the lower part of FIG. 5 shows the change over time in the current value of the power storage device 1. In the graph shown in the lower part of FIG. 5, the vertical axis represents the current value (A) and the horizontal axis represents the elapsed time (s). In the graph shown in the upper part of FIG. 5, the solid line represents the terminal voltage value Vb and the dashed line represents the estimated voltage value Ve. The terminal voltage value Vb is actual data of the terminal voltage measured by the voltage sensor 7a. The estimated voltage value Ve is an estimated value of the terminal voltage calculated by the above formula (1) based on the equivalent circuit model using an OCV corresponding to the estimated value of SOC obtained by the current integration method.

[0068] The control unit 21 of the management apparatus 2 acquires the voltage value (terminal voltage value) and the current value of the power storage device 1 measured by the voltage sensor 7a and the current sensor 7b at predetermined intervals and stores them as time-series data. For example, the current value is a positive value when charging and a negative value when discharging. First, the control unit 21 determines whether a temporary phenomenon is occurring (whether to start correction) by determining whether the power storage device 1 satisfies the following condition.

[0069] As the first condition, the control unit 21 determines whether the current value measured by the voltage sensor 7a satisfies the current condition. Specifically, it determines whether the absolute value of the current value is equal to or greater than a predetermined value (current threshold). If the absolute value of the current value is equal to or greater than the predetermined value, it is highly likely that a temporary phenomenon is occurring. If the absolute value of the current value of the power storage device 1 is equal to or greater than the predetermined value, it is estimated that a temporary phenomenon is highly likely to be occurring due to extreme uneven distribution of lithium ions in the electrodes of the power storage element 3. The predetermined value is set to a current value at which such uneven distribution of lithium ions occurs. Note that the first condition during charging is similar to the above, but the current threshold during discharging and charging may be different current values.

[0070] As a second condition, the control unit 21 determines whether or not the terminal voltage value Vb of the power storage device 1 measured by the voltage sensor 7a intersects with the estimated voltage value Ve of the power storage device 1 calculated based on the equivalent circuit model. If the terminal voltage value Vb intersects with the estimated voltage value Ve, there is a high possibility that a temporary phenomenon has occurred.

[0071] As shown in FIG. 5, during discharge of the energy storage device 1, before the occurrence of a temporary phenomenon, the internal resistance of the energy storage element 3 decreases as the temperature of the energy storage element 3 increases due to repeated charging and discharging, causing the terminal voltage value Vb to be greater than the estimated voltage value Ve. When an SOC unevenness occurs within the electrode body due to a temporary phenomenon, the terminal voltage value Vb decreases, and the terminal voltage value Vb becomes smaller than the estimated voltage value Ve. In other words, the terminal voltage value Vb decreases toward a value exceeding the estimated voltage value Ve. By determining the timing at which the terminal voltage value Vb and the estimated voltage value Ve intersect as the occurrence of the temporary phenomenon, i.e., the start timing of the correction process, the occurrence of an SOC error can be suitably detected. Note that the occurrence of the intersection of the terminal voltage value Vb and the estimated voltage value Ve is not a necessary condition for performing correction.

[0072] As a third condition, the control unit 21 determines whether the absolute value of the difference (|Vb-Ve|) between the terminal voltage value Vb and the estimated voltage value Ve is equal to or greater than a first threshold. If the absolute value of the difference is equal to or greater than the first threshold, it is highly likely that a temporary phenomenon is occurring. If the difference between the terminal voltage value Vb and the estimated voltage value Ve is equal to or greater than the first threshold, it is estimated that the voltage fluctuation (voltage drop during discharge) due to the occurrence of a temporary phenomenon is large, and the SOC error is large. Note that the third condition during charging is the same as above, but the first threshold during discharging and charging may be different values.

[0073] If the second condition is satisfied based on the current supply history of the power storage device 1 and the first and third conditions are also satisfied, the control unit 21 determines that a temporary phenomenon is occurring and therefore determines to correct the estimated SOC value. As described above, the second condition is not a necessary condition for determining the occurrence of a temporary phenomenon, but a preferred condition for early detection of the occurrence of a temporary phenomenon. The control unit 21 determines whether the state satisfying the above conditions has continued for a predetermined time or more, and if it has continued for the predetermined time or more, determines that the SOC fluctuation due to the occurrence of a temporary phenomenon is large and therefore determines to correct the estimated SOC value.

[0074] First, the control unit 21 determines the amount of change in the open-circuit voltage value over a predetermined time. The graph shown in Fig. 6 shows the time changes in the terminal voltage value Vb of the storage element 3 and the estimated voltage value Ve over a predetermined time. The vertical axis of Fig. 6 represents the terminal voltage (V), and the horizontal axis represents the elapsed time (s). In Fig. 6, the solid line represents the terminal voltage value Vb, and the dashed line represents the estimated voltage value Ve. The start time of the predetermined time that satisfies the first to third conditions is set to t1, and the end time is set to t2.

[0075] If the current value of the storage element 3 is constant from the start time t1 to the end time t2, the change in the open circuit voltage value Ve_Δocv related to the estimated voltage value Ve is calculated by subtracting the polarization change amount ΔVz from the change in the estimated voltage value Ve from the start time t1 to the end time t2. That is, the relationship of the following equations (2) and (3) is established. Ve_Δocv=(Ve(t2)-Ve(t1)) / n-ΔVz…(2) ΔVz=(Vz1(t2)+Vz2(t2))-(Vz1(t1)+Vz2(t1))…(3) Here, Ve_Δocv is the change in the open circuit voltage value of each storage element 3 (single cell) of the energy storage device 1, n is the number of storage elements 3 in the energy storage device 1 (4 in this embodiment), and Vz1 and Vz2 are the polarization amounts per cell calculated by a sequential calculation formula.

[0076] When the current value of the storage element 3 is constant, the difference in the amount of change between the estimated voltage value Ve and the terminal voltage value Vb is due to SOC fluctuations caused by temporary phenomena. The amount of change Vb_Δocv in the open circuit voltage value related to the terminal voltage value Vb is calculated by subtracting the amount of polarization change ΔVz shown in the above formula (3) from the amount of change in the terminal voltage value Vb from the start time t1 to the end time t2. In other words, the relationship shown in the following formula (4) holds. Vb_Δocv=(Vb(t2)-Vb(t1)) / n-ΔVz…(4) Here, Vb_Δocv is the amount of change in the open circuit voltage value of each energy storage element 3 (single cell) of the energy storage device 1, and n is the number of energy storage elements 3 in the energy storage device 1 (4 in this embodiment).

[0077] The control unit 21 calculates the change Vb_Δocv in the open circuit voltage from the start time t1 to the end time t2 using the measured values ​​of the terminal voltage at the start time t1 and the end time t2 and the polarization change ΔVz based on the equivalent circuit model, using the above equation (4).

[0078] The control unit 21 calculates the amount of change in SOC from the start time point t1 to the end time point t2, thereby calculating the amount of change in SOC ΔSOC of the power storage device 1 corresponding to the amount of change Vb_Δocv in the open circuit voltage value. Specifically, the control unit 21 calculates the amount of change in SOC ΔSOC from the start time point t1 to the end time point t2 by dividing the integrated value of the current from the start time point t1 to the end time point t2 by the current full charge capacity. ΔSOC corresponds to a predetermined amount of change in SOC over a predetermined period of time (hereinafter referred to as the predetermined SOC change amount).

[0079] Graphs shown in FIGS. 7 and 8 show the SOC-OCV characteristics of the power storage device 1. The vertical axis in FIGS. 7 and 8 represents open-circuit voltage (V), and the horizontal axis represents SOC (%). As shown in FIG. 7, the control unit 21 identifies an SOC region in which a correspondence relationship between a predetermined SOC change amount ΔSOC and Vb_Δocv holds on a profile (SOC-OCV characteristics) showing the relationship between the SOC and OCV of the power storage device 1. Specifically, the control unit 21 sequentially subtracts the predetermined SOC value from a preset search start SOC value, and identifies an SOC region in which Vb_Δocv is similar to the calculated value Vc_Δocv of the change in terminal voltage relative to the predetermined SOC change amount ΔSOC. For example, the control unit 21 may determine that Vc_Δocv and Vb_Δocv are similar when the absolute value of the difference between Vc_Δocv and Vb_Δocv (|Vc_Δocv-Vb_Δocv|) is less than a predetermined value.

[0080] The control unit 21 uses the SOC value within the identified SOC range as a correction value for the estimated SOC value. The method for selecting the SOC value within the SOC range is not limited. For example, the left end of the identified SOC range on the SOC-OCV characteristic shown in FIG. 7, i.e., the minimum SOC value within the SOC range, may be used as the correction value. When charging the power storage device 1, the right end of the identified SOC range, i.e., the maximum SOC value within the SOC range, may be used as the correction value. The obtained SOC value reflects temporary deterioration when a temporary phenomenon occurs. The obtained SOC value is referred to as the apparent SOC value. The control unit 21 corrects the SOC estimate based on the current integration method using the apparent SOC value.

[0081] After the correction, the control unit 21 determines whether the absolute value of the difference (|Vb-Ve|) between the terminal voltage value Vb and the estimated voltage value Ve is equal to or greater than a second threshold value (e.g., 0.1 V). Here, the estimated voltage value Ve is an estimated terminal voltage calculated by the above formula (1) based on an equivalent circuit model using an OCV corresponding to the apparent SOC value (the corrected SOC value). If the correction process is performed appropriately, the terminal voltage value Vb during discharge is predicted to be greater than the corrected estimated voltage value Ve. If the absolute value of the difference is equal to or greater than the second threshold value, the deviation between the terminal voltage value Vb and the estimated voltage value Ve is large, and it is predicted that the SOC value has not been sufficiently corrected.

[0082] If the absolute value of the difference is equal to or greater than the second threshold, as shown in FIG. 8, the control unit 21 adjusts the correction amount of the SOC value by successively adding a predetermined value (e.g., 0.1%) to the apparent SOC value. The area indicated by the dashed-dotted line on the lower side in FIG. 8 is an enlarged version of the area indicated by the dashed-dotted line on the upper side. The control unit 21 repeats the adjustment (re-correction) until the difference between the estimated voltage value Ve and the terminal voltage value Vb becomes less than the predetermined value. Alternatively, the control unit 21 may adjust the apparent SOC value by successively subtracting a predetermined value from the apparent SOC value. Note that the conditions for determining whether or not to perform adjustment during charging are the same as those described above, but the second threshold during discharging and charging may be different values.

[0083] The control unit 21 may execute the above-described adjustment process when the first condition at the start of correction, i.e., the condition that the absolute value of the current value is equal to or greater than a predetermined value, is continuously satisfied. If it is determined that the first condition at the start of correction is no longer satisfied, the control unit 21 resets the correction history. Specifically, the control unit 21 resets the history of intersections, which is the second condition at the start of correction, and the history of corrections to the apparent SOC value. If the power storage device 1 newly satisfies the current condition, which is the first condition at the start of correction, the above-described correction process is started from scratch.

[0084] 9 and 10 are flowcharts showing an example of a procedure for correcting the charged amount of electricity. The control unit 21 of the management device 2 executes the following process in accordance with the correction program 221. The control unit 21 executes the process according to the correction program 221 in parallel with the process for estimating the SOC using the current integration method. The control unit 21 executes the following process, for example, at predetermined or appropriate time intervals.

[0085] The control unit 21 acquires measurement data of the terminal voltage value Vb and current value of the power storage device 1 through the input unit 23 (step S11) and stores the data in the memory unit 22. The terminal voltage value Vb of the power storage device 1 is a measurement value measured in time series by the voltage sensor 7a. The current value of the power storage device 1 is a measurement value measured in time series by the current sensor 7b. When the management apparatus 2 is installed in a remote location, the control unit 21 receives the measurement data of the power storage device 1 by communication via the output unit 24.

[0086] The control unit 21 determines whether the current value satisfies a current condition based on the acquired measurement data as a first condition (step S12). The current condition is whether the absolute value of the current value is equal to or greater than a current threshold. The control unit 21 determines whether the absolute value of the current value is equal to or greater than a predetermined value (current threshold) that has been set in advance, and determines whether the absolute value of the current value is equal to or greater than the current threshold. The control unit 21 may execute the determination process from step S12 onwards every time it acquires measurement data from the input unit 23, or may store measurement data for a certain period in the memory unit 22 and then read the measurement data from the memory unit 22 to execute the determination process.

[0087] If it is determined that the current value does not satisfy the current condition, i.e., the absolute value of the current value is less than the current threshold (step S12: NO), the control unit 21 returns the process to step S12 and waits until the condition is satisfied. If it is determined that the current value satisfies the current condition, i.e., the absolute value of the current value is equal to or greater than the current threshold (step S12: YES), the control unit 21 proceeds to the process of determining whether the second condition exists.

[0088] As a second condition, the control unit 21 determines whether the terminal voltage value Vb and the estimated voltage value Ve intersect based on the history of the acquired measurement data (step S13). The terminal voltage value Vb is measurement data of the terminal voltage value measured by the voltage sensor 7a. The estimated voltage value Ve is an estimate of the terminal voltage value of the power storage device 1 calculated based on an equivalent circuit model. The control unit 21 reads the open-circuit voltage value OCV corresponding to the estimated SOC value in the pre-stored SOC-OCV characteristics based on the estimated SOC value at the time of determination using the current integration method. The control unit 21 calculates the estimated voltage value Ve by performing an operation using the read open-circuit voltage value OCV and known circuit parameters.

[0089] If it is determined that the terminal voltage value Vb and the estimated voltage value Ve do not intersect (step S13: NO), the control unit 21 returns the process to step S12 and waits until the condition is satisfied. If it is determined that the terminal voltage value Vb and the estimated voltage value Ve intersect (step S13: YES), the control unit 21 proceeds to the process of determining whether the third condition exists.

[0090] As a third condition, the control unit 21 determines whether the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve (|Vb-Ve|) is greater than or equal to a predetermined first threshold, and determines whether the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve is greater than or equal to the first threshold (step S14). If the control unit 21 determines that the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve is less than the first threshold (step S14: NO), the control unit 21 returns to step S12 and waits until the condition is satisfied. If the control unit 21 determines that the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve is greater than or equal to the first threshold (step S14: YES), the control unit 21 determines to perform correction and proceeds to determine whether the fourth condition is satisfied.

[0091] As a fourth condition, control unit 21 determines whether the state in which conditions 1 to 3 are satisfied has continued for a predetermined time or more (step S15). Specifically, control unit 21 determines whether a predetermined time or more has elapsed while the current condition and the voltage condition are satisfied from the first time point (start time) t1 at which the current condition, which is the first condition, and the voltage condition, which is the third condition, are satisfied after terminal voltage value Vb, which is the second condition, intersects with estimated voltage value Ve. If it is determined that the current condition and the voltage condition have not continued for the predetermined time or more (step S15: NO), control unit 21 returns the process to step S15 and waits until the current condition and the voltage condition have continued for the predetermined time or more.

[0092] If it is determined that the abnormality has continued for a predetermined time or longer (step S15: YES), the control unit 21 proceeds with the correction process. The control unit 21 calculates the amount of change Vb_Δocv in the open-circuit voltage value from the start time t1 to the end time t2 of the predetermined time (step S16). Note that the start time t1, end time t2, and time length of the predetermined time in the fourth condition and the predetermined time for calculating the amount of change Vb_Δocv in the open-circuit voltage value may be different from each other. The start time t1 for calculating the amount of change Vb_Δocv in the open-circuit voltage value may be any time that satisfies the first to third conditions, and the end time t2 may be a time when a predetermined time has elapsed since the start time t1.

[0093] The control unit 21 calculates the change in open-circuit voltage Vb_Δocv based on the measured terminal voltage values ​​at the start time t1 and the end time t2 and the polarization change ΔVz calculated by the equivalent circuit model. The control unit 21 calculates Vb_Δocv by subtracting the polarization change ΔVz from the change in terminal voltage Vb for each unit cell from the start time t1 to the end time t2.

[0094] The control unit 21 calculates the amount of change ΔSOC in the SOC of the power storage device 1 corresponding to the calculated amount of change Vb_Δocv in the open circuit voltage value (step S17). Specifically, the control unit 21 calculates the amount of change in the SOC (predetermined amount of SOC change) ΔSOC from the start time t1 to the end time t2 by dividing the integrated value of the current from the start time t1 to the end time t2 by the current full charge capacity.

[0095] The control unit 21 acquires an apparent SOC value based on the calculated predetermined SOC change amount ΔSOC and the change amount Vb_Δocv in the open circuit voltage (step S18). Specifically, the control unit 21 identifies an SOC region in the SOC-OCV characteristics where the calculated value Vc_Δocv of the change amount in the open circuit voltage corresponding to the predetermined SOC change amount ΔSOC is close to Vb_Δocv. The control unit 21 sets the SOC value within the identified SOC region as the apparent SOC value. The control unit 21 corrects the SOC estimated by current integration to the acquired apparent SOC value (step S19).

[0096] The control unit 21 determines whether the absolute value of the difference (|Vb-Ve|) between the terminal voltage value Vb and the corrected estimated voltage value Ve is greater than or equal to a predetermined second threshold value (step S20). Based on the SOC value corrected using the current integration method, the control unit 21 reads the open-circuit voltage value OCV corresponding to the corrected SOC value from the pre-stored SOC-OCV characteristics. The control unit 21 calculates the corrected estimated voltage value Ve by performing an operation using the read open-circuit voltage value OCV and known circuit parameters.

[0097] If it is determined that the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve is less than the second threshold value (step S20: NO), the control unit 21 ends the series of processes. If it is determined that the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve is equal to or greater than the second threshold value (step S20: YES), the control unit 21 determines whether the state in which the current value of the power storage device 1 satisfies the current condition of the first condition has ended (step S21).

[0098] If it is determined that the state satisfying the current condition has not ended (step S21: NO), the control unit 21 adjusts (re-corrects) the apparent SOC value by adding or subtracting a predetermined value to or from the apparent SOC value (step S22). After the adjustment, the control unit 21 returns to step S20 and repeats the adjustment of the apparent SOC value until the absolute value of the difference between the corrected estimated voltage value Ve and the terminal voltage value Vb becomes less than the second threshold value.

[0099] If it is determined that the state satisfying the current condition has ended (step S21: YES), control unit 21 resets the correction history (step S23) and ends the series of processes. Specifically, control unit 21 resets the history of intersection, which is the second condition at the start of correction, and the history of correction to the apparent SOC value. Control unit 21 may output the corrected SOC value or information based on the corrected SOC value to a display device or the like via output unit 24.

[0100] After the above-described processing, the control unit 21 may estimate the SOC by a current integration method using the apparent SOC value obtained by the above-described processing.

[0101] In the above, the SOC is corrected as the amount of charged electricity. Alternatively, the amount of charged electricity may be the value of the amount of energy currently stored in the power storage device 1, for example, the amount of power.

[0102] According to this embodiment, when a temporary phenomenon occurs in the power storage device 1, the estimated value of the SOC can be corrected with high accuracy by reflecting the SOC fluctuation caused by the temporary phenomenon.

[0103] (Second embodiment) In the second embodiment, the correction based on the apparent SOC value is terminated when the power storage device 1 satisfies a predetermined condition. The following mainly describes the differences from the first embodiment, and the same reference numerals are used to designate the same components as the first embodiment, and detailed descriptions thereof will be omitted.

[0104] Fig. 11 is an explanatory diagram illustrating the concept of correction termination based on the apparent SOC value. The graph shown in Fig. 11 shows the SOC-OCV characteristics of the electricity storage device 1. The vertical axis of Fig. 11 represents open circuit voltage (V), and the horizontal axis represents SOC (%).

[0105] The control unit 21 of the management device 2 executes the process described in the first embodiment and corrects the SOC estimate based on the current integration using the apparent SOC value. The control unit 21 sets the corrected SOC estimate as a new initial value (reference value) and executes subsequent SOC estimation. If the power storage device 1 satisfies a predetermined condition, the control unit 21 ends the correction based on the apparent SOC value. When the correction is completed, the control unit 21 restores the SOC value from the apparent SOC value to the SOC estimate based on the current integration. In other words, the control unit 21 restores the SOC value to the SOC estimate before correction. The control unit 21 sets the SOC estimate based on the current integration as a new initial value (reference value) and executes subsequent SOC estimation.

[0106] The predetermined condition for ending the correction is not limited, but as an example, when the apparent SOC value becomes equal to or greater than a preset third threshold value during charging of the power storage device 1, the control unit 21 ends the correction based on the apparent SOC value. The third threshold value may be set to, for example, the lower end of the plateau region (the minimum SOC value in the plateau region). As another example, the control unit 21 may end the correction based on the apparent SOC value when a signal to start full charge control is received from the vehicle ECU or the like.

[0107] 12 is a flowchart showing an example of a correction termination process in the second embodiment. The control unit 21 determines whether or not the power storage device 1 satisfies a predetermined condition (step S31). As an example, the control unit 21 determines whether or not the apparent SOC value is equal to or greater than a third threshold. If the apparent SOC value is less than the third threshold, the control unit 21 determines that the predetermined condition is not satisfied. If the apparent SOC value is equal to or greater than the third threshold, the control unit 21 determines that the predetermined condition is satisfied.

[0108] If it is determined that the power storage device 1 does not satisfy the predetermined condition (step S31: NO), the control unit 21 ends the process. That is, if it is determined that the power storage device 1 does not satisfy the predetermined condition, the control unit 21 does not end the correction using the apparent SOC value. If it is determined that the power storage device 1 satisfies the predetermined condition (step S31: YES), the control unit 21 ends the correction using the apparent SOC value, restores the SOC value of the power storage device 1 from the apparent SOC value to an SOC estimated by current integration (step S32), and ends the series of processes.

[0109] According to this embodiment, the correction range based on the apparent SOC value is limited, thereby improving the accuracy of correcting the SOC value in the power storage device 1.

[0110] The correction method, correction device, and program can be applied to applications other than vehicles, and may be applied to flying bodies such as aircraft, flying vehicles, and HAPS (High Altitude Platform Stations), as well as to ships and submarines.The correction method, correction device, and program are preferably applied to mobile bodies that require a high level of safety (requiring correction of the SOC value in real time), but may also be applied to stationary electricity storage devices other than mobile bodies.

[0111] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims. [Explanation of symbols]

[0112] 1. Energy storage devices 2 Management device (correction device) 21 Control Unit 22 Memory section 23 Input section 24 Output section 221 Correction Program 222 Correction Data 2A Recording Media 3. Energy storage element

Claims

1. determining whether a difference between a terminal voltage value of the power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold value; When it is determined that the difference is equal to or greater than a first threshold, a corrected amount of charge electricity in the power storage device is derived based on a predetermined amount of change in the amount of charge electricity corresponding to the integrated current value of the power storage device and an amount of change in the open-circuit voltage value obtained from the equivalent circuit model. A correction method in which processing is performed by a computer.

2. identifying a region of the charged quantity of electricity that satisfies a correspondence relationship between a predetermined amount of change in the charged quantity of electricity and an amount of change in the open-circuit voltage value in a profile that indicates a relationship between the charged quantity of electricity and an open-circuit voltage value of the power storage device; The corrected charged quantity of electricity is derived based on the identified charged quantity of electricity region. The correction method according to claim 1 .

3. The amount of change in the open-circuit voltage value is calculated by subtracting the difference in the polarization voltage value related to the equivalent circuit model at the first time point and the second time point from the difference in the terminal voltage value at the first time point and the second time point when the difference is equal to or greater than a first threshold value. The correction method according to claim 1 or 2.

4. determining whether the terminal voltage value and the estimated voltage value intersect based on a current history of the power storage device; When it is determined that the terminal voltage value and the estimated voltage value intersect, the corrected charged quantity of electricity is derived. The correction method according to any one of claims 1 to 3.

5. When the difference between the terminal voltage value and the estimated voltage value after the derivation of the corrected charged quantity of electricity is equal to or greater than a second threshold, the corrected charged quantity of electricity is re-derived by sequentially adding or subtracting a predetermined value to the derived corrected charged quantity of electricity. The correction method according to any one of claims 1 to 4.

6. When the corrected charge quantity of electricity becomes equal to or greater than a third threshold, the derivation of the corrected charge quantity of electricity is terminated and the charge quantity of electricity is returned to the estimated value before derivation. The correction method according to any one of claims 1 to 5.

7. The electricity storage device has a plateau region. The correction method according to any one of claims 1 to 6.

8. determining whether a difference between a terminal voltage value of the power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold value; When it is determined that the difference is equal to or greater than a first threshold, a corrected amount of charge electricity in the power storage device is derived based on a predetermined amount of change in the amount of charge electricity corresponding to the integrated current value of the power storage device and an amount of change in the open-circuit voltage value obtained from the equivalent circuit model. A computer program that causes a computer to perform a process.

9. a control unit that executes control related to correction of an estimated value of a charged amount of electricity of the power storage device; The control unit determining whether a difference between a terminal voltage value of the power storage device when current is applied and an estimated voltage value estimated using an equivalent circuit model of the power storage device is equal to or greater than a first threshold value; When it is determined that the difference is equal to or greater than a first threshold, a corrected amount of charge electricity in the power storage device is derived based on a predetermined amount of change in the amount of charge electricity corresponding to the integrated current value of the power storage device and an amount of change in the open-circuit voltage value obtained from the equivalent circuit model. Correction device.

10. a storage element; and a correction device according to claim 9. A power storage device comprising:

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