WO2023027049A1

WO2023027049A1 - Correcting method, computer program, correcting apparatus, and electricity storage device

Info

Publication number: WO2023027049A1
Application number: PCT/JP2022/031642
Authority: WO
Inventors: 直也和田
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2021-08-26
Filing date: 2022-08-23
Publication date: 2023-03-02
Also published as: JP2023032183A

Abstract

This correcting method determines whether a difference between a terminal voltage value when an electricity storage device is energized and an estimated voltage value estimated using an equivalent circuit model of the electricity storage device is at least equal to a first threshold. In the correcting method, if it is determined that the difference is at least equal to the first threshold, a computer executes processing to correct an estimated value of an amount of charged electricity in the electricity storage device on the basis of an amount of change in an open-circuit voltage value of the electricity storage device corresponding to a prescribed amount of change in the amount of charged electricity in the electricity storage device, obtained from the equivalent circuit model.

Description

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

The present invention relates to a correction method, a computer program, a correction device, and an electricity storage device.

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

In the OCV method, the SOC is estimated from the voltage value of the storage element obtained by the voltage sensor using the one-to-one correlation (SOC-OCV characteristic) between the OCV (Open Circuit Voltage) of the storage element and the SOC. In the current integration method, the SOC is estimated by measuring the current value of the charging/discharging current of the storage element at predetermined time intervals with a current sensor and adding or subtracting the measured current value to the initial value.

If the current integration continues for a long period of time, the measurement error of the current sensor accumulates, so the estimation error due to the current integration method increases 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.

Patent Document 1 discloses an SOC management device that can prevent the correction accuracy of the SOC of the battery from deteriorating when the OCV is reset.

Japanese Unexamined Patent Application Publication No. 2021-12106

The conventional SOC management device does not have sufficient accuracy in correcting the state of charge.

An object of the present disclosure is to provide a correction method and the like that can improve the accuracy of correcting the amount of charged electricity in an electricity storage device.

A correction method according to an aspect of the present disclosure determines whether a difference between a terminal voltage value when an electricity storage device is energized and an estimated voltage value estimated using an equivalent circuit model of the electricity storage device is equal to or greater than a first threshold. determine whether In the correction method, when it is determined that the difference is equal to or greater than the first threshold, the amount of change in the open-circuit voltage value of the power storage device according to the predetermined amount of change in the amount of charged electricity of the power storage device, which is obtained from the equivalent circuit model. A computer executes a process of correcting the estimated value of the charged quantity of electricity in the power storage device based on.

According to the present disclosure, it is possible to improve the accuracy of correcting the amount of charged electricity in the power storage device.

1 is a perspective view showing a configuration example of a power storage device on which a management device according to a first embodiment is mounted; FIG. 1 is an exploded perspective view showing a configuration example of an electricity storage device; FIG. 3 is a block diagram showing a configuration example of a management device and the like; FIG. 2 is a circuit diagram showing an example of an equivalent circuit model of an electricity storage device; FIG. FIG. 4 is an explanatory diagram for explaining a method of correcting SOC; FIG. 4 is an explanatory diagram for explaining a method of correcting SOC; FIG. 4 is an explanatory diagram for explaining a method of correcting SOC; FIG. 4 is an explanatory diagram for explaining a method of correcting SOC; It is a flowchart which shows an example of the correction|amendment process procedure of charge quantity of electricity. It is a flowchart which shows an example of the correction|amendment process procedure of charge quantity of electricity. FIG. 5 is an explanatory diagram for explaining the concept of termination of correction based on an apparent SOC value; FIG. 11 is a flow chart showing an example of a processing procedure for ending correction in the second embodiment; FIG.

The correction method determines whether the difference between the terminal voltage value when the power storage device is energized and the estimated voltage value estimated using the equivalent circuit model of the power storage device is greater than or equal to the first threshold. In the correction method, when it is determined that the difference is equal to or greater than the first threshold, the amount of change in the open-circuit voltage value of the power storage device according to the predetermined amount of change in the amount of charged electricity of the power storage device, which is obtained from the equivalent circuit model. A computer executes a process of correcting the estimated value of the charged quantity of electricity in the power storage device based on.

In the correction method, when it is determined that the difference (absolute difference) between the terminal voltage value when the power storage device is energized and the estimated voltage value estimated using the equivalent circuit model of the power storage device is equal to or greater than a first threshold, Correct the estimated value of the amount of charge in the power storage device.

The charged quantity of electricity may be SOC, for example. The SOC is indicated by the ratio of the remaining capacity to the full charge capacity of the storage element.
The terminal voltage value of the electricity storage device is, for example, the voltage value of the electricity storage device acquired by a voltage sensor.
The estimated value of the amount of charged electricity in the power storage device may be an estimated value of the SOC obtained by the current integration method. In the current integration method, a current sensor is used to measure the charge/discharge current of the storage element at predetermined time intervals. This is a method of estimating the SOC by adjusting from the full charge capacity.
The open-circuit voltage value (OCV) is the voltage value when the amount of current flowing through the storage element is zero and is not affected by polarization, and when the amount of current flowing through the storage element is less than the threshold value and when the storage element is This also includes the voltage value of the storage element when the amount of current flowing is as small as the dark current.

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

The present inventor paid attention to the following points when using, for example, an electricity storage element (secondary battery) having an electrode body containing lithium iron phosphate, lithium manganate, or the like as a positive electrode active material as an electricity storage device.
The above secondary battery has a plateau region in the SOC-OCV characteristics, in which the OCV hardly changes with respect to changes in SOC over a wide range. That is, there is almost no voltage difference between the portion of the electrode body where the charge/discharge reaction has progressed and the portion where the charge/discharge reaction has not progressed. Therefore, during charging and discharging of the electricity storage device, SOC unevenness (SOC imbalance) occurs in the electrode body, such that the SOC is only partially high or low.

When SOC unevenness occurs, the effective battery capacity is temporarily lower than the original battery capacity of the power storage device. In a state where the battery capacity is temporarily lowered, for example, during discharging, the battery voltage drops earlier than predicted based on the original battery capacity. When SOC unevenness occurs in a power storage device used in a vehicle, the actual terminal voltage is lower than the predicted voltage. may decrease. The phenomenon of temporary deterioration (decrease) in charging/discharging performance due to such SOC unevenness becomes particularly conspicuous in high-current charging/discharging under low-temperature conditions. Since the correlation between the SOC and the OCV is not established when the above-described temporary phenomenon occurs, the SOC estimation error increases when the normal OCV reset is performed.

In this correction method, the SOC is calculated based on the amount of change in the open-circuit voltage value (OCV) of the electricity storage device according to the predetermined amount of change in the amount of charge (for example, SOC) of the electricity storage device, which is obtained from the equivalent circuit model of the electricity storage device. Correct the estimate. This makes it possible to correct the SOC in consideration of voltage fluctuations due to temporary phenomena. Even if a temporary phenomenon occurs, the SOC can be accurately corrected.

The presence or absence of the occurrence of a temporary phenomenon, that is, the necessity of correction, is determined when the difference between the terminal voltage value when the power storage device is energized and the estimated voltage value estimated using the equivalent circuit model of the power storage device is equal to or greater than the first threshold. It is determined by whether or not Whether correction is necessary or not can be efficiently determined based on the difference between the measured data of the terminal voltage value and the estimated voltage value easily calculated by the equivalent circuit model.

As a result, it is possible to predict the short-term voltage and power characteristics of the storage device, even during charging and discharging, so-called SOF (State Of Function) estimation. For example, in response to the question "What is the maximum current value that does not fall below the target voltage after a certain period of time?" The device's management unit (eg, battery management unit) can respond appropriately.

The correction method includes, in the profile indicating the relationship between the charged quantity of electricity and the open circuit voltage value of the power storage device, a charged quantity of electricity region that satisfies the corresponding relationship between the predetermined amount of change in the charged quantity of electricity and the amount of change in the open circuit voltage value. The estimated value of the charged quantity of electricity may be corrected based on the specified charged quantity of electricity region.

According to the above configuration, the estimated SOC value can be efficiently corrected using the profile (SOC-OCV characteristic) that indicates the relationship between the amount of charged electricity and the open-circuit voltage value of the power storage device. Based on the amount of change in the open-circuit voltage value due to the amount of change in the SOC due to a temporary phenomenon, the SOC region is specified according to the amount of change in the open-circuit voltage value using a known SOC-OCV characteristic. can be suitably corrected.

The correction method calculates the difference in the polarization voltage value according 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. The amount of change in the open-circuit voltage value may be calculated by subtracting.

According to the above configuration, it is possible to easily and accurately calculate the amount of change in the open-circuit voltage value with respect to the amount of change in the terminal voltage value based on the actual measurement data of the actual battery test.

The correction method is to determine whether or not the terminal voltage value and the estimated voltage value intersect based on the energization history of the power storage device, and when it is determined that the terminal voltage value and the estimated voltage value intersect. , the estimated value of the charged quantity of electricity may be corrected.

According to the above configuration, the occurrence of the temporary phenomenon described above is detected by determining whether or not the terminal voltage value and the estimated voltage value intersect. By setting the occurrence timing of this phenomenon as the correction start timing, the correction can be started promptly according to the occurrence of the phenomenon, so that the estimation accuracy can be further improved.

In the correction method, when the difference between the terminal voltage value and the estimated voltage value after the correction of the charged quantity of electricity is equal to or greater than a second threshold value, a predetermined value is sequentially added or subtracted from the corrected charged quantity of electricity. By doing so, the estimated value of the charged quantity of electricity may be re-corrected.

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). The estimation error or measurement error can be reduced, and the estimation accuracy can be further improved.

As for the correction method, when the charge quantity of electricity after correction becomes equal to or greater than a third threshold, the correction of the estimated value of the charge quantity of electricity may be terminated, and the estimated value of the charge quantity of electricity may be returned to the pre-correction estimate.

According to the above configuration, correction by this correction method is performed only when it is estimated that there is a temporary phenomenon. By limiting the correction by this correction method in the SOC range estimated to be unaffected by this phenomenon, the SOC change due to the phenomenon can be appropriately reflected, and the estimated SOC value can be corrected satisfactorily.

The computer program determines whether the difference between the terminal voltage value of the power storage device when energized and the estimated voltage value estimated using the equivalent circuit model of the power storage device is equal to or greater than a first threshold. When the computer program determines that the difference is equal to or greater than the first threshold, the amount of change in the open-circuit voltage value of the power storage device according to the predetermined amount of change in the amount of charged electricity of the power storage device obtained from the equivalent circuit model. causes the computer to execute a process of correcting the estimated value of the charged quantity of electricity in the power storage device based on.

The correction device includes a control unit that executes control related to correction of the estimated value of the charge amount of electricity of the power storage device. The control unit determines whether or not a difference between a terminal voltage value when the power storage device is energized 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. When the controller determines that the difference is equal to or greater than the first threshold value, the control unit changes the open-circuit voltage value of the power storage device according to a predetermined amount of change in the amount of charged electricity of the power storage device, which is obtained from the equivalent circuit model. correcting the estimated value of the charged quantity of electricity in the power storage device based on the quantity;

The electricity storage device includes an electricity storage element and the correction device described above.

Hereinafter, the present disclosure will be specifically described with reference to the drawings showing its embodiments.

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

The power storage device 1 has a management device (correction device) 2 and a rectangular parallelepiped housing case 4 a that houses a plurality of power storage elements 3 . The storage element 3 may be a battery cell such as a lithium ion secondary battery. The management device 2 is, for example, a battery management system (BMS). The housing case 4a also houses a plurality of bus bars 5, various sensors (see FIG. 3), and the like. 1 and 2, the storage device 3 is housed in the storage case 4a in a state of an assembled battery 30 formed by connecting four in series.

The storage case 4a is made of synthetic resin. The storage case 4a includes a case body 41, a lid portion 42 that closes an opening of the case body 41, a storage portion 43 provided on the outer surface of the lid portion 42, a cover 44 that covers the storage portion 43, and an inner lid 45. and a partition plate 46. The inner lid 45 and partition plate 46 may not be provided. The storage element 3 is inserted between each partition plate 46 of the case body 41 .

A plurality of metal busbars 5 are mounted on the inner lid 45 . An inner lid 45 is arranged near the terminal surface where the terminals 32 of the storage elements 3 are provided, and the adjacent terminals 32 of the adjacent storage elements 3 are connected by the bus bars 5, and the storage elements 3 are connected in series. .

The accommodating part 43 has a box shape and has a protruding part 43a that protrudes outward at the center of one long side surface in a plan view. A pair of

external terminals

6, 6 made of a metal such as a lead alloy and having different polarities are provided on both sides of the projecting portion 43a of the lid portion 42. As shown in FIG. The accommodation unit 43 accommodates the management device 2 which is a flat circuit board. The management device 2 is connected to the storage element 3 via a conductor (not shown). The management device 2 manages the states of the plurality of power storage elements 3 and controls each part of the power storage device 1 .

The storage element 3 is a battery cell having the aforementioned plateau region, such as an LFP battery. The storage element 3 includes a hollow rectangular parallelepiped case 31 and a pair of

terminals

32 , 32 with different polarities provided on one side surface (terminal surface) of the case 31 . The case 31 encloses an electrode body 33 formed by stacking a positive electrode 33a, a separator 33b, and a negative electrode 33c, and an electrolyte (electrolytic solution) (not shown).

The electrode body 33 is configured by stacking a sheet-like positive electrode 33a and a negative electrode 33c with two sheet-like separators 33b interposed therebetween, and winding them (vertically or horizontally). The separator 33b is made of a porous resin film. As the porous resin film, a porous resin film made of resin such as polyethylene (PE) and polypropylene (PP) can be used.

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 base material made of, for example, aluminum, an aluminum alloy, or the like. The positive electrode active material layer contains a positive electrode active material. As the positive electrode active material used for the positive electrode active material layer, a material capable of intercalating and deintercalating lithium ions can be used. Examples of positive electrode active materials include LiFePO ₄ . The positive electrode active material layer may further contain a conductive aid, a binder, and the like.

The negative electrode 33c is an electrode plate in which a negative electrode active material layer is formed on the surface of a long belt-shaped negative electrode base material made of, for example, copper or a copper alloy. The negative electrode active material layer contains a negative electrode active material. A material capable of intercalating and deintercalating lithium ions can be used as the negative electrode active material. Examples of negative electrode active materials include graphite, hard carbon, and soft carbon. The negative electrode active material layer may further contain a binder, a thickener, and the like.

As the electrolyte enclosed in the case 31, the same one as in conventional lithium ion secondary batteries can be used. For example, an electrolyte containing a supporting salt in an organic solvent can be used as the electrolyte. As organic solvents, for example, aprotic solvents such as carbonates, esters and ethers are used. Lithium salts such as LiPF ₆ , LiBF ₄ and LiClO ₄ are preferably used as supporting salts. The electrolyte may contain various additives such as, for example, gas generating agents, film forming agents, dispersants, thickeners, and the like.

In FIGS. 1 and 2, as an example of the storage element 3, a rectangular lithium ion battery including a wound electrode body 33 has been described. Alternatively, the storage element 3 may be a cylindrical lithium ion battery. The storage element 3 may be a lithium ion battery including a laminated electrode body, or may be a laminated (pouch type) lithium ion battery or the like. Furthermore, the storage element 3 may be an all-solid lithium ion battery using a solid electrolyte.

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

A power storage device 1 equipped with a 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 with power (regenerated power) supplied from the starter motor. Also, when the starter motor functions as a power source, the power storage device 1 supplies power to the starter motor and other electronic devices.

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

The control unit 21 is an arithmetic circuit including a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and the like. The CPU provided in the control unit 21 executes various computer programs stored in the ROM and the storage unit 22, and controls the operation of each hardware unit described above, so that the entire device functions as a management device (correction device) of the present disclosure. make it work. The control unit 21 may have functions such as a timer that measures the elapsed time from when the measurement start instruction is given until when the measurement end instruction is given, a counter that counts the number, and a clock that outputs date and time information.

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

The correction data 222 includes information such as an equivalent circuit model of the electricity storage device 1 used in the simulation, SOC-OCV characteristics corresponding to the electricity storage device 1, and various threshold values used for correction processing. The equivalent circuit model is described by configuration information indicating the circuit configuration, the values of each element configuring the equivalent circuit model, and the like. The storage unit 22 stores the configuration information indicating the circuit configuration of such an equivalent circuit model, the values of each element configuring the equivalent circuit model, and the like. The control unit 21 acquires information on the equivalent circuit model, SOC-OCV characteristics, and various threshold values in advance by communicating with, for example, an external device (not shown), and stores the acquired information in the correction data 222 . The SOC-OCV characteristic may be updated at predetermined time intervals in consideration of deterioration accompanying use of the electricity storage device 1 .

The computer program stored in the storage unit 22 may be provided by a non-temporary recording medium 2A on which the computer program is readable. The recording medium 2A is a portable memory such as a CD-ROM, USB memory, SD (Secure Digital) card, or the like. The control unit 21 uses a reading device (not shown) to read a desired computer program from the recording medium 2A and stores the read computer program in the storage unit 22 . Alternatively, the computer program may be provided by communication. Correction program 221 may be deployed to run on a single computer or on multiple computers located at one site or distributed across multiple sites and interconnected by a communications network. can be done.

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

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, and measures the voltage across the terminals of each storage element 3 in time series. The control unit 21 acquires data on the voltage of each storage element 3 and the total voltage of the assembled battery 30 measured by the voltage sensor 7a through the input unit 23 at any time. The current sensor 7b is connected in series with the storage element 3 and measures the current flowing through the storage element 3 in time series. The control unit 21 acquires current data measured by the current sensor 7b through the input unit 23 at any time.

The output unit 24 has an interface for connecting a display device (not shown). An example of a display device is a liquid crystal display device. When the information about the amount of electricity charged in the electricity storage device 1 is obtained, the control unit 21 outputs the information about the amount of electricity charged in the electricity storage device 1 from the output unit 24 to the display device. The display device displays information about the charge quantity of electricity based on the information output from the output unit 24 .

Alternatively, the output unit 24 may have a communication interface that communicates with an external device (not shown). An external device communicably connected to the output unit 24 is a terminal device such as a personal computer or a smart phone used by a user or administrator. The control unit 21 outputs information about the amount of electricity charged in the power storage device 1 from the output unit 24 to the external device. The output unit 24 may include a communication interface that communicates with the vehicle ECU 8 . The control unit 21 outputs information about the amount of electricity charged in the power storage device 1 from the output unit 24 to the vehicle ECU. The management device 2 may include a notification unit such as an LED lamp or a buzzer in order to notify the user of information regarding the amount of electricity charged in the power storage device 1 .

1 to 3 show examples in which the management device 2 is a BMS. Alternatively, management device 2 may be placed at a location remote from storage element 3 . The management device 2 may include a server device or an ECU that is located away from the power storage element 3 and communicates with the BMS. The place where the amount of electricity charged in the power storage device 1 is corrected is not limited, and the correction may be performed, for example, in a server device or an ECU. In this case, measurement data measured with respect to the power storage device 1 may be transmitted to the server device or the ECU through communication.

1 to 3 show an in-vehicle low-voltage power supply provided with a storage element 3, which is a lithium-ion secondary battery, as the storage device 1. FIG. The storage element 3 may be another secondary battery or electrochemical cell having a plateau region.

4 is a circuit diagram showing an example of an equivalent circuit model of the electricity storage device 1. FIG. The equivalent circuit model combines the voltage source of the electricity storage device 1 and circuit elements such as resistors and capacitors to simulate the charging and discharging behavior of the electricity storage device 1 . The equivalent circuit model includes a constant voltage source connected in series between a positive terminal and a negative terminal, a DC resistor for simulating a DC resistance component, and an RC parallel circuit for simulating transient polarization characteristics. Prepare. 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.

A 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 storage device 1 and is denoted as Vo. The open-circuit voltage value Vo is given as a function of SOC, for example. The open-circuit voltage value Vo may be given as a function of the actual capacity of the electricity storage device 1 .

The DC resistor is for simulating the DC resistance component (DC impedance) of the electricity storage device 1, and includes a resistance element R0. The resistance element R0 is given as a value that fluctuates according to the applied current, voltage, SOC, temperature, and the like. Once the impedance of the DC resistor is determined, the voltage generated in the DC resistor when the current I flows through this equivalent circuit model can be calculated. A voltage generated in the DC resistor is defined as a DC resistance voltage value Vz0.

The first RC parallel circuit is composed of a resistance element R1 and a capacitance element C1 connected in parallel. A second RC parallel circuit is composed of a resistance element R2 and a capacitance element C2 that are connected in parallel. Resistive elements R1, R2 and capacitive elements C1, C2 forming each RC parallel circuit are given values that vary according to the SOC of the electric storage device 1, temperature, and the like. The impedance of the RC parallel circuit is determined by the resistive elements R1, R2 and the capacitive elements C1, C2. Once the impedance of the RC parallel circuit is determined, the voltage generated in the RC parallel circuit when current I flows through this equivalent circuit model can be calculated. The voltage generated in the RC parallel circuit is the total voltage 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.

In the above equivalent circuit model, the estimated value of the terminal voltage (estimated voltage value) Ve(t) at the time when time t has elapsed after starting the simulation is the DC resistance voltage value Vz0(t), the polarization voltage value Vz1(t ), the polarization voltage value Vz2(t), and the open-circuit voltage value Vo(t), it can be expressed by the following formula (1).
Ve(t)=Vo(t)+Vz0(t)+(Vz1(t)+Vz2(t)) (1)

The resistive element R0, resistive elements R1, R2, and capacitive elements C1, C2 (hereinafter also referred to as circuit parameters) that constitute the equivalent circuit model are obtained by a known method. The circuit parameters can be set, for example, based on actual measurement data of battery tests, taking into consideration the relationship between temperature, SOC, and the like. The estimated voltage value Ve of the storage element 3 can be calculated by using the open-circuit voltage value of the storage element 3 and known circuit parameters.

The management device 2 in this embodiment estimates the SOC of the electricity storage device 1 by the current integration method at appropriate intervals and stores it in the storage unit 22 . Specifically, the management device 2 calculates the amount of power flowing into and out of the power storage device 1 by integrating the 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 estimation time by adding or subtracting the calculated power amount to or from the full charge capacity at the reference time (initial). Alternatively, the management device 2 may acquire an SOC estimated value calculated by an external device (not shown) through communication.

In parallel with estimating the SOC by the current integration method, the management device 2 determines whether or not the power storage device 1 has the temporary phenomenon described above. When this phenomenon occurs, the management device 2 corrects the SOC estimated value based on the current integration by the following correction method. 5 to 8 are explanatory diagrams for explaining the SOC correction method. A method of correcting the SOC according to the present embodiment will be described with reference to FIGS. 5 to 8, taking discharge as an example.

The graph shown on the upper side of FIG. 5 shows temporal changes in the terminal voltage value Vb of the electricity storage device 1 and the estimated voltage value Ve. In the graph shown on the upper side of FIG. 5, the vertical axis is the terminal voltage (V) and the horizontal axis is the elapsed time (s). The graph shown on the lower side of FIG. 5 shows the time change of the current value of the electricity storage device 1 . In the graph shown on the lower side of FIG. 5, the vertical axis is the current value (A) and the horizontal axis is the elapsed time (s). In the upper graph of FIG. 5, the solid line indicates the terminal voltage value Vb, and the broken line indicates the estimated voltage value Ve. The terminal voltage value Vb is actually measured data of the terminal voltage measured by the voltage sensor 7a. The estimated voltage value Ve is the terminal voltage estimated value calculated by the above equation (1) based on the equivalent circuit model using the OCV corresponding to the SOC estimated value obtained by the current integration method.

The control unit 21 of the management device 2 acquires the voltage value (terminal voltage value) and current value of the electricity storage device 1 measured by the voltage sensor 7a and the current sensor 7b at predetermined intervals, and stores them as time-series data. The current value is, for example, a positive value for charging and a negative value for charging.
First, the control unit 21 determines whether a temporary phenomenon has occurred (whether to start correction) by determining whether the power storage device 1 satisfies the following conditions.

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 is determined whether or not 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 greater than or equal to the predetermined value, there is a high possibility that a temporary phenomenon has occurred. When the absolute value of the current value of the electricity storage device 1 is equal to or greater than a predetermined value, it is highly likely that a temporary phenomenon has occurred due to extreme uneven distribution of lithium ions in the electrodes of the electricity storage element 3 . As the predetermined value, a current value at which such uneven distribution of lithium ions occurs is set. The first condition during charging is also the same as above, but the current thresholds during discharging and charging may be different current values.

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

As shown in FIG. 5, during discharging of the storage device 1, before a temporary phenomenon occurs, the internal resistance of the storage device 3 decreases as the temperature of the storage device 3 rises due to repeated charging and discharging. , the terminal voltage value Vb becomes larger than the estimated voltage value Ve. Occurrence of SOC unevenness in the electrode body due to a temporary phenomenon causes the terminal voltage value Vb to drop and the terminal voltage value Vb to become smaller than the estimated voltage value Ve. In other words, the terminal voltage value Vb decreases to exceed the estimated voltage value Ve. By setting the timing at which the terminal voltage value Vb and the estimated voltage value Ve cross each other as the timing of the occurrence of a temporary phenomenon, that is, the timing of starting correction processing, the occurrence of an SOC error can be preferably detected. Note that occurrence of intersection between the terminal voltage value Vb and the estimated voltage value Ve is not an essential condition for executing the correction.

As a third condition, the control unit 21 determines whether or not 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 the first threshold. If the absolute value of the difference is greater than or equal to the first threshold, there is a high possibility that a temporary phenomenon has occurred. When 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. The third condition during charging is also the same as above, but the first threshold during discharging and during charging may have different values.

Based on the energization history of the electricity storage device 1, if the second condition and the first and third conditions are satisfied, the control unit 21 estimates the SOC because it is estimated that a temporary phenomenon has occurred. Determine to correct the value. As described above, the second condition is not an essential condition for determining the occurrence of a temporary phenomenon, but a suitable condition for detecting the occurrence of a temporary phenomenon at an early stage. The control unit 21 determines whether or not the state satisfying the above conditions has continued for a predetermined time or longer. Determine to correct the value.

First, the control unit 21 obtains the amount of change in the open-circuit voltage value for a predetermined period of time. The graph shown in FIG. 6 shows temporal changes in the terminal voltage value Vb of the storage element 3 and the estimated voltage value Ve during a predetermined period of time. The vertical axis of FIG. 6 is the terminal voltage (V), and the horizontal axis is the elapsed time (s). In FIG. 6, the solid line indicates the terminal voltage value Vb, and the dashed line indicates the estimated voltage value Ve. Let t1 be the start time and t2 be the end time of the predetermined time that satisfies the first to third conditions.

When the current value of the storage element 3 is constant from the start time t1 to the end time t2, the amount of change Ve_Δocv in the open-circuit voltage value related to the estimated voltage value Ve is the change in the estimated voltage value Ve from the start time t1 to the end time t2. ΔVz is subtracted from the amount of change in polarization. That is, the relationships of the following formulas (2) and (3) are 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 amount of change in the open-circuit voltage value of each storage element 3 (single cell) of the storage device 1, n is the number of storage elements 3 in the storage device 1 (4 in this embodiment), Vz1 and Vz2 are It is the amount of polarization per cell calculated by a sequential calculation formula.

When the current value of storage element 3 is constant, the difference in variation between estimated voltage value Ve and terminal voltage value Vb is caused by SOC fluctuation due to a temporary phenomenon. The amount of change Vb_Δocv in the open-circuit voltage value related to the terminal voltage value Vb is obtained by subtracting the amount of change in polarization ΔVz given by the above equation (3) from the amount of change in the terminal voltage value Vb from the start time t1 to the end time t2. Become. That is, the relationship of the following formula (4) is established.
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 storage element 3 (single cell) of the storage device 1, and n is the number of storage elements 3 in the storage device 1 (4 in this embodiment).

The control unit 21 calculates using the measured values of the terminal voltage values at the start time t1 and the end time t2 and the polarization change amount ΔVz by the equivalent circuit model. The change amount Vb_Δocv of the open-circuit voltage value up to is calculated.

By calculating the amount of change in SOC from the start time t1 to the end time t2, the control unit 21 calculates the amount of change ΔSOC in the SOC of the electric storage device 1 corresponding to the amount of change Vb_Δocv in the open-circuit voltage value. Specifically, the control unit 21 divides the current integrated value from the start time t1 to the end time t2 by the current full charge capacity to obtain the SOC change amount ΔSOC from the start time t1 to the end time t2. Ask for ΔSOC corresponds to a predetermined amount of change in SOC in a predetermined period (hereinafter referred to as a predetermined amount of change in SOC).

The graphs shown in FIGS. 7 and 8 show the SOC-OCV characteristics of the electricity storage device 1. The vertical axis in FIGS. 7 and 8 is the open-circuit voltage (V), and the horizontal axis is the SOC (%). As shown in FIG. 7, the control unit 21 controls the SOC where the correspondence relationship between the predetermined SOC change amount ΔSOC and Vb_Δocv is established on the profile (SOC-OCV characteristic) showing the relationship between the SOC and OCV of the electricity storage device 1. Identify areas. Specifically, the control unit 21 sequentially subtracts a predetermined SOC value from a search start SOC value set in advance, and calculates an SOC that approximates the calculated value Vc_Δocv of the change amount of the terminal voltage with respect to the predetermined SOC change amount ΔSOC and Vb_Δocv. Identify areas. For example, when the absolute value of the difference between Vc_Δocv and Vb_Δocv (|Vc_Δocv−Vb_Δocv|) is less than a predetermined value, the control unit 21 may determine that Vc_Δocv and Vb_Δocv are close to each other.

The control unit 21 uses the SOC value within the specified SOC region as the correction value for the estimated SOC value. The method of selecting the SOC value in the SOC region is not limited, but for example, on the SOC-OCV characteristics shown in FIG. 7, the left end of the specified SOC region, that is, the minimum SOC value in the SOC region may be used as the correction value. During charging of the power storage device 1, the right end of the specified SOC region, that is, the maximum SOC value in the SOC region may be used as the correction value. The obtained SOC value is an SOC value reflecting temporary deterioration when a temporary phenomenon occurs. The obtained SOC value is called an apparent SOC value. The control unit 21 corrects the estimated value of the SOC obtained by the current integration method using the apparent SOC value.

After 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 (eg, 0.1 V). Here, the estimated voltage value Ve is an estimated value of the terminal voltage calculated by the above equation (1) based on the equivalent circuit model using OCV corresponding to the apparent SOC value (SOC value after correction). If an appropriate correction process is performed, the terminal voltage value Vb is predicted to be higher than the post-correction estimated voltage value Ve during discharge. If the absolute value of the difference is equal to or greater than the second threshold, the divergence between the terminal voltage value Vb and the estimated voltage value Ve is large, so it is estimated that the SOC value is not sufficiently corrected.

When the absolute value of the difference is equal to or greater than the second threshold, as shown in FIG. 8, the control unit 21 sequentially adds a predetermined value (for example, 0.1%) to the apparent SOC value, thereby increasing the SOC value. Adjust the correction amount. The lower one-dot chain line area in FIG. 8 is an enlarged view of the upper one-dot chain line area. The control unit 21 repeats adjustment (re-correction) until the difference between the estimated voltage value Ve and the terminal voltage value Vb becomes less than a predetermined value. Alternatively, the control unit 21 may adjust the apparent SOC value by successively subtracting a predetermined value from the apparent SOC value. Although the conditions for determining whether or not adjustment is performed during charging are the same as above, the second threshold values during discharging and during charging may be different values.

The control unit 21 may execute the adjustment process described above when the first condition at the start of correction, ie, the condition that the absolute value of the current value is equal to or greater than a predetermined value, is continuously satisfied. When determining that the first condition at the time of correction start is no longer satisfied, the control unit 21 resets the correction history. Specifically, the control unit 21 resets the history of crossing, which is the second condition at the start of correction, and the history of correction to the apparent SOC value. When the power storage device 1 newly satisfies the current condition, which is the first condition for starting correction, the correction process described above is started from scratch.

9 and 10 are flowcharts showing an example of a procedure for correcting the amount of charged electricity. The control unit 21 of the management device 2 executes the following processes according to the correction program 221. FIG. The control unit 21 executes processing by the correction program 221 in parallel with the SOC estimation processing by the current integration method. The control unit 21 executes the following processes, for example, at predetermined or appropriate time intervals.

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

As the first condition, the control unit 21 determines whether or not the current value satisfies the current condition based on the acquired measurement data (step S12). The current condition is whether or not the absolute value of the current value is greater than or equal to the current threshold. The control unit 21 determines the magnitude relationship between the absolute value of the current value and a preset predetermined value (current threshold value), and determines whether the absolute value of the current value is equal to or greater than the current threshold value. The control unit 21 may execute the determination process after step S12 each time measurement data is acquired from the input unit 23, and after storing the measurement data for a certain period in the storage unit 22, the measurement data is stored in the storage unit 22. may be read out to execute the determination process.

When it is determined that the current value does not satisfy the current condition, that is, the absolute value of the current value is less than the current threshold value (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, that is, the absolute value of the current value is equal to or greater than the current threshold (step S12: YES), the control unit 21 advances the processing to determination of the second condition.

As a second condition, the control unit 21 determines whether or not 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 estimated value of the terminal voltage value of the electricity storage device 1 calculated based on the 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 characteristic based on the estimated SOC value at the time of determination by the current integration method. The control unit 21 calculates the estimated voltage value Ve by performing calculation using the read open-circuit voltage value OCV and known circuit parameters.

When 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 conditions are 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 advances the processing to determination of the third condition.

As a third condition, the control unit 21 determines the magnitude relationship between the absolute value of the difference between the terminal voltage value Vb and the estimated voltage value Ve (|Vb−Ve|) and a preset first threshold, It is determined whether or not 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). When 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 first threshold (step S14: NO), the control unit 21 returns the process to step S12 and waits until the condition is satisfied. do. When 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 first threshold value (step S14: YES), the control unit 21 determines to execute correction, and furthermore, the fourth condition Proceed to judgment.

As the fourth condition, the control unit 21 determines whether or not the state of satisfying the first to third conditions has continued for a predetermined time or longer (step S15). Specifically, the control unit 21 first satisfies the current condition, which is the first condition, and the voltage condition, which is the third condition, after the intersection of the terminal voltage value Vb and the estimated voltage value Ve which are the second condition. (Start point) From t1, it is determined whether or not a predetermined time or more has passed while the current condition and the voltage condition are satisfied. If it is determined that it has not continued for the predetermined time or longer (step S15: NO), the control unit 21 returns the process to step S15 and waits until it continues for the predetermined time or longer.

If it is determined that it has continued for the predetermined time or longer (step S15: YES), the control unit 21 proceeds with the correction process. The control unit 21 calculates the change amount Vb_Δocv of 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, the end time t2, and the time length of the predetermined time under the fourth condition and the predetermined time related to the calculation of the change amount Vb_Δocv of the open-circuit voltage value may be different. The start time t1 for calculating the change amount Vb_Δocv of the open-circuit voltage value may be any time that satisfies the first to third conditions, and the end time t2 is a time after a predetermined time has elapsed from the start time t1. There may be.

The control unit 21 calculates the change amount Vb_Δocv of the open-circuit voltage value based on the measured values of the terminal voltage values at the start time t1 and the end time t2 and the polarization change amount ΔVz by the equivalent circuit model. The control unit 21 calculates Vb_Δocv by subtracting the polarization change amount ΔVz from the change amount of the terminal voltage value Vb from the start time t1 to the end time t2 for each single cell.

The control unit 21 calculates the amount of change ΔSOC in the SOC of the electricity 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 divides the integrated value of the current from the start time t1 to the end time t2 by the current full charge capacity to obtain the SOC change amount from the start time t1 to the end time t2 ( Predetermined SOC change amount) ΔSOC is obtained.

The control unit 21 acquires the apparent SOC value based on the calculated predetermined SOC change amount ΔSOC and the open-circuit voltage value change amount Vb_Δocv (step S18). Specifically, in the SOC-OCV characteristic, the control unit 21 identifies an SOC region in which the calculated value Vc_Δocv of the change amount of the open-circuit voltage value corresponding to the predetermined SOC change amount ΔSOC approximates 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 estimated value of the SOC obtained by current integration to the obtained apparent SOC value (step S19).

The control unit 21 determines the magnitude relationship between the absolute value of the difference between the terminal voltage value Vb and the corrected estimated voltage value Ve (|Vb−Ve|) and a preset second threshold. It is determined whether or not the absolute value of the difference between the voltage value Vb and the corrected estimated voltage value Ve is greater than or equal to the second threshold (step S20). Based on the SOC value after correction by the current integration method, the control unit 21 reads the open-circuit voltage value OCV corresponding to the SOC value after correction in the SOC-OCV characteristic stored in advance. The control unit 21 calculates the corrected estimated voltage value Ve by performing calculations using the read open-circuit voltage value OCV and known circuit parameters.

When determining 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 (step S20: NO), the controller 21 terminates the series of processes.
When determining 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 (step S20: YES), the control unit 21 sets the current value of the electricity storage device 1 to the first condition. (step S21).

If it is determined that the current condition is not satisfied (step S21: NO), the controller 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 the process 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.

When it is determined that the current condition is satisfied (step S21: YES), the control unit 21 resets the correction history (step S23) and ends the series of processes. Specifically, the control unit 21 resets the history of crossing, which is the second condition at the start of correction, and the history of correction to the apparent SOC value. The 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 the output unit 24 .

After the above process, the control unit 21 may estimate the SOC by the current integration method using the apparent SOC value obtained by the above process.

In the above description, the SOC is corrected as the charge quantity of electricity. Alternatively, the amount of charged electricity may be the value of the current amount of energy stored in the power storage device 1, and may be the amount of electric power, for example.

According to the present embodiment, the SOC estimated value can be accurately corrected by reflecting the SOC fluctuation corresponding to the temporary phenomenon in response to the occurrence of the temporary phenomenon in the electricity storage device 1 .

(Second embodiment)
In the second embodiment, correction based on the apparent SOC value ends when the power storage device 1 satisfies a predetermined condition. In the following, the differences from the first embodiment will be mainly described, and the same reference numerals will be given to the configurations common to the first embodiment, and detailed description thereof will be omitted.

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

The control unit 21 of the management device 2 executes the processing described in the first embodiment, and corrects the SOC estimated value by current integration based on the apparent SOC value. The control unit 21 performs subsequent SOC estimation using the corrected SOC estimated value as a new initial value (reference value). If the power storage device 1 satisfies a predetermined condition, the control unit 21 terminates the correction based on the apparent SOC value. When the correction is finished, the control unit 21 restores the SOC value from the apparent SOC value to the estimated SOC value obtained by current integration. In other words, the control unit 21 restores the SOC value to the estimated SOC value before correction. The control unit 21 uses the estimated value of the SOC obtained by the current integration as a new initial value (reference value) to perform the subsequent estimation of the SOC.

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

FIG. 12 is a flowchart showing an example of a processing procedure for ending correction 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 greater than or equal to the third threshold. When the apparent SOC value is less than the third threshold, the control unit 21 determines that the predetermined condition is not satisfied. When the apparent SOC value is equal to or greater than the third threshold, the control unit 21 determines that the predetermined condition is satisfied.

When it is determined that the power storage device 1 does not satisfy the predetermined condition (step S31: NO), the control unit 21 terminates the process. That is, when it is determined that the power storage device 1 does not satisfy the predetermined condition, the control unit 21 does not end the correction based on the apparent SOC value. When it is determined that the power storage device 1 satisfies the predetermined condition (step S31: YES), the control unit 21 ends the correction based on the apparent SOC value, and converts the SOC value of the power storage device 1 from the apparent SOC value to the SOC calculated by current integration. The estimated value is restored (step S32), and the series of processing ends.

According to the present embodiment, by limiting the correction range based on the apparent SOC value, the correction accuracy of the SOC value in the electricity storage device 1 can be improved.

The correction method, correction device, and program can be applied to applications other than vehicles, and may be applied to flying objects such as aircraft, flying vehicles, HAPS (High Altitude Platform Station), and to ships and submarines. may be The correction method, correction apparatus, and program are preferably applied to mobile objects that require a high degree of safety (requires correction of SOC values in real time), but are not limited to mobile objects and can be applied to stationary power storage devices. may be

The embodiments disclosed this time should be considered as examples 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 of equivalents to the scope of the claims. be done.

1 power storage device 2 management device (correction device)
21 control unit 22 storage unit 23 input unit 24 output unit 221 correction program 222 correction data 2A recording medium 3 storage element

Claims

determining whether a difference between a terminal voltage value when the power storage device is energized 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;
When it is determined that the difference is equal to or greater than the first threshold, based on the amount of change in the open-circuit voltage value of the electricity storage device according to the predetermined amount of change in the amount of charged electricity of the electricity storage device, obtained from the equivalent circuit model, A correction method in which a computer executes a process of correcting the estimated value of the charged quantity of electricity in the power storage device.
In the profile indicating the relationship between the charged quantity of electricity and the open circuit voltage value of the power storage device, specifying a charged quantity of electricity region that satisfies the corresponding relationship between the predetermined amount of change in the charged quantity of electricity and the amount of change in the open circuit voltage value,
The correction method according to claim 1, wherein the estimated value of the charged quantity of electricity is corrected based on the specified charged quantity of electricity region.
By subtracting the difference in the polarization voltage value according 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 where the difference is equal to or greater than the first threshold 3. The correction method according to claim 1 or 2, wherein the amount of change in said open-circuit voltage value is calculated.
determining whether the terminal voltage value and the estimated voltage value intersect based on the energization history of the electricity storage device;
The correction method according to any one of claims 1 to 3, further comprising correcting the estimated value of the charged quantity of electricity when it is determined that the terminal voltage value and the estimated voltage value intersect.
When the difference between the terminal voltage value and the estimated voltage value after the correction of the charge quantity of electricity is equal to or greater than a second threshold, by sequentially adding or subtracting a predetermined value to the corrected charge quantity of electricity, the The correction method according to any one of claims 1 to 4, further comprising recorrecting the estimated value of the charged quantity of electricity.
When the charge quantity of electricity after correction becomes equal to or greater than a third threshold, the correction of the estimated value of the charge quantity of electricity is terminated, and the estimated value of the charge quantity of electricity before correction is restored. The correction method according to any one of the items.
determining whether a difference between a terminal voltage value when the power storage device is energized 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;
When it is determined that the difference is equal to or greater than the first threshold, based on the amount of change in the open-circuit voltage value of the electricity storage device according to the predetermined amount of change in the amount of charged electricity of the electricity storage device, obtained from the equivalent circuit model, A computer program that causes a computer to execute a process of correcting the estimated value of the charge quantity of electricity in the power storage device.
A control unit that executes control related to correction of the estimated value of the charge amount of electricity of the power storage device,
The control unit
determining whether a difference between a terminal voltage value of the electricity storage device when energized and an estimated voltage value estimated using an equivalent circuit model of the electricity storage device is equal to or greater than a first threshold;
When it is determined that the difference is equal to or greater than the first threshold, based on the amount of change in the open-circuit voltage value of the electricity storage device according to the predetermined amount of change in the amount of charged electricity of the electricity storage device, obtained from the equivalent circuit model, A correction device that corrects the estimated value of the amount of charge in the power storage device.
An electricity storage device comprising: an electricity storage element; and the correction device according to claim 8 .