JP2017161351A - Charging rate estimation method of secondary battery, charging rate estimation device, and charging rate estimation program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a conventional charging rate estimation method in which an error in charge rate estimation value due to memory effect increases.SOLUTION: A charging rate estimation method includes: calculating, based on a charge/discharge current measurement value and a temperature measurement value, a model voltage value indicative of an amplitude of voltage variation component of a secondary battery caused by factors other than electromotive voltage; calculating an electromotive voltage estimation value which is estimation value of the electromotive voltage of the secondary battery by subtracting the model voltage value from a battery voltage measurement value; calculating a charge rate estimation value indicative of an estimated charge rate of the secondary battery based on the charge/discharge current measurement value, the temperature measurement value and the battery voltage measurement value; calculating a correction value based on a difference between an initial charge/discharge curve indicative of the relation between an initial charge rate estimation value of the secondary battery calculated before start of use and initial electromotive voltage estimation value, and a current charge/discharge curve indicative of the relation between a charge rate estimation value calculated during a prescribed period after the start of use and the electromotive voltage estimation value; and correcting the charge rate estimation value based on the correction value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a charging rate estimation method, a charging rate estimation device, and a charging rate estimation program for a secondary battery, and more particularly, to estimate a charging rate estimate value of a secondary battery based on measured values such as battery voltage and charge / discharge current of the secondary battery. The present invention relates to a secondary battery charging rate estimation method, a charging rate estimation device, and a charging rate estimation program.

  In recent years, the use of secondary batteries has also expanded in automobiles and the like. The secondary battery has a memory effect in which the charging rate estimated from the output voltage value of one secondary battery varies by repeatedly charging and discharging. Therefore, when using a secondary battery, it is necessary to determine the estimated charge rate of the secondary battery in consideration of the memory effect. Therefore, Patent Document 1 discloses a technique for estimating a change in output characteristics of a secondary battery due to a memory effect.

  In the method for controlling an electrochemical element described in Patent Document 1, the state of an electrochemical element including an electrode and an ionic conductor is changed to an electrode potential model, an electrode electron transport model, an electrode ion transport model, and an ion conductor. Analysis using at least one model selected from the group consisting of an ion transport model and a model representing an electrochemical reaction that occurs at the interface between an electrode and an ionic conductor. Control properties.

Japanese Patent Laid-Open No. 2000-1000047

  Here, a change in the relationship between the estimated charging rate of the secondary battery and the estimated electromotive voltage due to the memory effect will be described. FIG. 5 is a graph showing changes in the estimated electromotive voltage with respect to the estimated charge rate, which explains the memory effect in the secondary battery. Here, the estimated electromotive voltage value is a value obtained by subtracting a voltage fluctuation component that varies due to a factor other than the electromotive voltage of the secondary battery from the measured battery voltage value obtained by measuring the secondary battery. In FIG. 5, the initial charge curve and the initial discharge curve calculated from the characteristics measured before the secondary battery are shipped (hereinafter, the two curves are collectively referred to as the initial charge / discharge curve) and the memory effect. The charge curve and the discharge curve after the characteristic variation occurred are shown.

  As shown in FIG. 5, in the secondary battery, when a memory effect occurs, the estimated electromotive voltage decreases in a region where the estimated charging rate is low during discharging, and the estimated electromotive voltage is estimated in a region where the estimated charging rate is high during charging. An increase in value occurs. Therefore, when the charge rate estimation value is calculated from the charge / discharge current and the battery voltage of the secondary battery, due to the voltage fluctuation due to the memory effect, for example, when calculating the charge rate estimate value corresponding to the measured battery voltage, There is a possibility that a charging rate estimation value lower than the original value is derived during discharging, and a charging rate estimation value higher than the original value is derived during charging.

  Therefore, a method for calculating the estimated charge rate assuming this memory effect is required. However, the charge rate estimated value at which the change in the estimated voltage due to the memory effect occurs varies depending on the usage state of the secondary battery, such as the number of times the secondary battery is charged and discharged, and the charge / discharge start voltage. Therefore, even if the memory effect is analyzed using the technique described in Patent Document 1, it is difficult to analyze the difference in the estimated charge rate at which the memory effect due to the difference in the usage state occurs. That is, even if the memory effect estimation method described in Patent Document 1 is used, there is a problem that the error in the estimated charge rate due to the memory effect cannot be sufficiently corrected.

  This invention is made | formed in view of the said situation, and aims at raising the precision of the charging rate estimated value of a secondary battery.

  One aspect of the method for estimating the charging rate of the secondary battery according to the present invention is to estimate the charging rate of the secondary battery based on the measured charge / discharge current value, the measured battery voltage value, and the measured temperature value obtained by measuring the secondary battery. A method for estimating a charging rate of a secondary battery, wherein a model voltage value indicates a magnitude of a voltage fluctuation component generated by a factor other than an electromotive voltage of the secondary battery based on the measured charge / discharge current value and the measured temperature value Subtracting the model voltage value from the battery voltage measurement value to calculate an electromotive voltage estimation value that is an estimation value of the secondary battery electromotive voltage, and calculating the charge / discharge current measurement value, the temperature measurement value, and the A charge rate estimated value indicating a charge rate of the secondary battery estimated based on a battery voltage measurement value is calculated, and an initial charge rate estimated value and an initial electromotive voltage estimated value calculated before the start of use of the secondary battery are calculated. Initial charge / discharge curve showing the relationship and predetermined after start of use A correction value is calculated based on a difference between the charge rate estimated value calculated during the period and a current charge / discharge curve indicating a relationship between the electromotive voltage estimated value, and the charge rate estimated value is corrected based on the correction value. .

  According to one aspect of the method for estimating the charging rate of the secondary battery according to the present invention, the charging rate estimation calculated using the correction value for correcting the error of the charging rate estimation value caused by the memory effect in the secondary battery. The accuracy of the value can be increased.

  Another aspect of the method for estimating the charging rate of the secondary battery according to the present invention is to shift the current charging / discharging curve in a direction in which the estimated charging rate increases or decreases, and among the plurality of data constituting the current charging / discharging curve A shift amount of the current charging / discharging curve until a predetermined number or more of data matches the initial charging / discharging curve is output as the correction value.

  According to another aspect of the method for estimating the charging rate of the secondary battery according to the present invention, the correction value of the charging rate estimated value can be calculated by a process with a small amount of calculation such as a numerical value shift process.

  According to another aspect of the method for estimating the charging rate of a secondary battery according to the present invention, the correction value is calculated using data relating to a part of the current charge / discharge curve.

  According to another aspect of the method for estimating the charging rate of the secondary battery according to the present invention, the correction value for the estimated charging rate can be calculated even when the entire charging / discharging curve is unknown.

  One aspect of the secondary battery charge rate estimation apparatus according to the present invention is generated due to factors other than the electromotive voltage of the secondary battery based on the measured value of charge / discharge current of the secondary battery and the measured temperature of the secondary battery. A model voltage value calculation unit for calculating a model voltage value indicating the magnitude of the voltage fluctuation component to be obtained, and subtracting the model voltage value from the battery voltage measurement value of the secondary battery to obtain an estimated value of the electromotive voltage of the secondary battery A subtractor for calculating an estimated electromotive voltage value, and a charge rate estimated value indicating a charge rate of the secondary battery estimated based on the measured charge / discharge current value, the measured temperature value, and the measured battery voltage value of the secondary battery A charge rate estimation unit that calculates the initial charge / discharge curve indicating the relationship between the charge rate estimated value calculated before the start of use of the secondary battery and the electromotive voltage estimated value, and a predetermined period after the start of use The charging rate estimated value and the electromotive voltage estimated value calculated in A correction value calculation unit that calculates a correction value based on a difference between the current charge / discharge curve and the charge rate estimation unit that corrects the charge rate estimation value calculated based on the correction value To do.

  According to one aspect of the secondary battery charging rate estimation device according to the present invention, the charging rate estimation is calculated using a correction value that corrects an error in the charging rate estimation value caused by the memory effect in the secondary battery. The accuracy of the value can be increased.

  One aspect of a rechargeable battery charging rate estimation program according to the present invention is executed in a calculation unit, and obtains a charge / discharge current measurement value, a battery voltage measurement value, and a temperature measurement value obtained by measuring a secondary battery from the outside. A secondary battery charge rate estimation program for estimating the charge rate of the secondary battery based on the acquired measurement value, wherein the secondary battery start-up is based on the charge / discharge current measurement value and the temperature measurement value. Dell voltage value calculation processing for calculating a model voltage value indicating the magnitude of a voltage fluctuation component generated due to a factor other than voltage, and an estimated value of the electromotive voltage of the secondary battery by subtracting the model voltage value from the battery voltage measurement value A subtraction process for calculating an estimated electromotive voltage value, and a charge rate estimated value indicating a charge rate of the secondary battery estimated based on the measured charge / discharge current value, the measured temperature value, and the measured battery voltage value Charge rate estimation process and An initial charge / discharge curve indicating a relationship between the charge rate estimated value calculated before the start of use of the secondary battery and the electromotive voltage estimated value, and the charge rate estimated value calculated during a predetermined period after the start of use. And a correction value calculation process for calculating a correction value based on a difference between the current charge / discharge curve indicating the relationship between the estimated voltage value and the charge voltage estimation value. In the correction value calculation process, the charge rate estimation value is calculated based on the correction value. Correct.

  According to one aspect of the secondary battery charging rate estimation program according to the present invention, the charging rate estimation is calculated using a correction value that corrects an error in the charging rate estimation value caused by the memory effect in the secondary battery. The accuracy of the value can be increased.

1 is a block diagram of a charging rate estimation apparatus according to a first embodiment. FIG. 10 is a diagram for explaining a first example of correction value calculation processing in a correction value calculation unit according to the first embodiment; FIG. 6 is a diagram for explaining a second example of correction value calculation processing in the correction value calculation unit according to the first embodiment; 3 is a flowchart for explaining the operation of the charging rate estimation apparatus according to the first embodiment; It is a graph which shows the change of the electromotive force estimated value with respect to the charging rate explaining the memory effect in a secondary battery.

  For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Each element described in the drawings as a functional block for performing various processes can be configured by a CPU, a memory, and other circuits in terms of hardware, and a program loaded in the memory in terms of software. Etc. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof, and is not limited to any one. Note that, in each drawing, the same element is denoted by the same reference numeral, and redundant description is omitted as necessary.

  Further, the above-described program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROM (Read Only Memory) CD-R, CD -R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

Embodiment 1
The charging rate estimation apparatus 1 according to the first embodiment converts the charging rate estimation value of the secondary battery into a battery voltage measurement value, a charge / discharge current measurement value, and a temperature measurement value obtained by measuring the secondary battery. Calculate based on Moreover, the charging rate estimation apparatus 1 according to the first embodiment is realized by a program executed in an arithmetic device such as a microcontroller, for example. The microcontroller also has an analog-to-digital conversion circuit that takes in an analog value parameter such as a voltage used in arithmetic processing as a digital value. Furthermore, the microcontroller has an output interface or a communication interface for outputting the estimated charging rate of the secondary battery to the upper system. In the following description, the charging rate estimation apparatus 1 will be described using a block diagram in which processing in a program is replaced with processing blocks for each type of processing. Moreover, the control apparatus 1 concerning Embodiment 1 is suitable for a secondary battery (for example, nickel hydride storage battery) with the big influence of a memory effect.

  FIG. 1 shows a block diagram of a charging rate estimation apparatus 1 according to the first embodiment. As illustrated in FIG. 1, the charging rate estimation apparatus 1 according to the first embodiment includes a model voltage value calculation unit 10, a subtractor 11, a charging rate estimation unit 12, and a correction value calculation unit 13. In addition, in the charging rate estimation apparatus 1 according to the first embodiment, the calculation using the battery voltage measurement value, the charge / discharge current measurement value, and the temperature measurement value is performed. These measurement values are targets for calculating the charge rate estimation value. Is a value acquired from a voltage sensor, a current sensor, a temperature sensor, or the like attached to the secondary battery.

The model voltage value calculation unit 10 calculates a model voltage value indicating the magnitude of a voltage fluctuation component generated by a factor other than the electromotive voltage of the secondary battery based on the measured charge / discharge current value and the measured temperature value. The model voltage value is calculated using a battery voltage model. Various models of battery voltage models have been proposed, and a model to be adopted can be selected depending on product specifications, accuracy of values to be obtained, and the like. However, the model voltage value calculation unit 10 according to the first embodiment adopts a model represented by the expression (1). The battery voltage model that can be adopted in the model voltage value calculation unit 10 according to the first embodiment is not limited to the expression (1).
Vmdl = Vlp + Vhys + Vir_d (1)

  In the equation (1), Vmdl is a model voltage value, Vlp is a polarization voltage value that is a fluctuation component of the battery voltage accompanying the diffusion of a substance in the battery, and Vhys is a value when the secondary battery is in an initial state. This is the difference between the electromotive voltage during charging and the electromotive voltage during discharging, and Vir_d is a voltage drop component due to the DC resistance component of the secondary battery. The model voltage value calculator 10 calculates the model voltage value Vmdl based on the equation (1) after calculating these parameters from the measured charge / discharge current value and the measured temperature value.

The subtractor 11 calculates the estimated electromotive voltage value Vemf_set by subtracting the model voltage value Vmdl calculated by the model voltage value calculation unit 10 from the battery voltage measurement value. The calculated electromotive force estimated value Vemf_set is given to the correction value calculating unit 13. Further, the estimated electromotive voltage value Vemf_set is expressed by equation (2), where the battery voltage measurement value is Vbat.
Vemf_set = Vbat−Vmdl (2)

  The charging rate estimation unit 12 calculates a charging rate estimated value indicating the charging rate of the secondary battery estimated based on the measured charging / discharging current value, the measured temperature value, and the measured battery voltage value. Specifically, the charging rate estimation unit 12 performs an accumulation process of the charge / discharge current measurement values. More specifically, the charge rate estimation unit 12 is a value calculated based on the measured charge / discharge current value, the measured temperature value, and the measured battery voltage value, and indicates the magnitude of the offset error of the current sensor. Calculate an estimate. And the charging rate estimation part 12 integrate | accumulates the value which correct | amended the charging / discharging electric current measured value by the electric current sensor offset error estimated value as the charging / discharging electric current actually charged / discharged by the secondary battery. And the charging rate estimation part 12 calculates the charging rate estimated value of a secondary battery based on the integrated electric current value. Furthermore, the charging rate estimation value calculated based on the correction value δSOC output from the charging rate estimation unit 12 and the correction value calculation unit 13 is corrected, and the corrected charging rate estimation value is output as the final charging rate estimation value. .

  The correction value calculation unit 13 is calculated for an initial charge / discharge curve indicating the relationship between the initial charge rate estimated value and the initial electromotive voltage estimated value calculated before the start of use of the secondary battery, and for a predetermined period after the start of use. The correction value δSOC is calculated based on the difference between the charging rate estimated value and the current charging / discharging curve indicating the relationship between the electromotive voltage estimated value Vemf_set. Here, before the start of use of a secondary battery means that the product using the secondary battery is used by the final user, such as before the product is shipped from the battery manufacturer, before the product equipped with the secondary battery is shipped. There is no particular limitation on the period as long as it is before the period. On the other hand, “after the start of use of the secondary battery” refers to a period after the product using the secondary battery starts to be used by the final user. Further, the predetermined period is a period until a predetermined number of data composed of a combination of the electromotive voltage estimated value Vemf_set and the charging rate estimated value is obtained.

  A method of calculating the correction value δSOC in the correction value calculation unit 13 will be described with a specific example. FIG. 2 is a diagram for explaining a first example of the correction value calculation process in the correction value calculation unit 13 according to the first embodiment.

  As shown in FIG. 2, in the correction value calculation unit 13, the initial charge / discharge curve calculated from the estimated electromotive voltage Vemf_set and the charge rate estimation value acquired before the start of use is stored in the correction value calculation unit 13. Read from the device. The storage device is a non-volatile memory and is incorporated in the correction value calculation unit in one example. However, the storage device may be incorporated in the charging rate estimation device 1 according to the first embodiment, and is externally attached. It may be. Then, the correction value calculation unit 13 obtains a current charge curve and a current discharge curve indicating the current charge / discharge characteristics of the secondary battery from the accumulated data when a predetermined number of data can be accumulated after the start of use. create. In the following description, the current charge curve and the current discharge curve are collectively referred to as a current charge / discharge curve.

  Then, the correction value calculation unit 13 shifts the current charging / discharging curve until a predetermined number or more of the data constituting the generated current charging / discharging curve matches the initial charging / discharging curve. That is, the correction value calculation unit 13 calculates a correction value using data related to a part of the current charge / discharge curve. The direction in which the current charge / discharge curve is shifted is the charge rate estimated value direction. The correction value calculation unit 13 determines the shift amount until a predetermined number or more of the data constituting the current charge / discharge curve coincides with the initial charge / discharge curve as the correction value δSOC.

  In the first example shown in FIG. 2, the data before the shift process is indicated by hatched circles, and the data after the shift process is indicated by white circles. In the first example shown in FIG. 2, by shifting the current charging / discharging curve in the direction in which the estimated charge rate becomes smaller, five pieces of data on the current charging curve that match the initial charging curve coincide with the initial discharging curve. The current discharge curve data is 3 pieces. When the correction value δSOC is determined, if the number of data in the current charge / discharge curve to be matched with the initial charge / discharge curve is larger than the number of matched data before correction, the estimation accuracy of the charging rate is improved. I can say. For example, although it depends on the range in which data is acquired, it is preferable if the portions of 2% or more in terms of charge rate match.

  As another example, FIG. 3 illustrates a second example of the correction value calculation process in the correction value calculation unit according to the first embodiment. The second example shown in FIG. 3 is an example in which part of the data constituting the current charge / discharge curve matches the initial charge / discharge curve when the current charge / discharge curve is shifted in the direction in which the estimated charge rate increases. is there. Thus, if the current charging curve matches the initial charging curve and the current discharging curve matches the initial discharging curve, the correction value calculation unit 13 calculates the shift amount at that time as the correction value δSOC. Thus, the correction value to be calculated when the data constituting a part of the current charge curve and the data constituting a part of the current discharge curve both coincide with a part of the initial charge curve and a part of the initial discharge curve. The accuracy of δSOC can be increased.

  As shown in FIG. 5, in the secondary battery, the difference in the estimated electromotive voltage due to the memory effect is caused by a part of the charging curve (the charging rate is high) and a part of the discharging curve (charging). The rate estimate is the lower side). Therefore, by generating a current charging / discharging curve while using a secondary battery and shifting this in the direction of the charge rate estimation value, at least data in a region where the voltage fluctuation due to the memory effect is small in the current charging / discharging curve. It matches the initial charge / discharge curve. That is, the correction value δSOC calculated by the correction value calculation unit 13 is not affected by the voltage component that varies due to the memory effect, and can correct the error due to the voltage variation due to the memory effect.

  Then, operation | movement of the charging rate estimation apparatus 1 concerning Embodiment 1 is demonstrated. FIG. 4 is a flowchart for explaining the operation of the charging rate estimation apparatus 1 according to the first embodiment. As shown in FIG. 4, in the charging rate estimation apparatus 1 according to the first embodiment, when the charging rate calculation process is started, first, the model voltage calculation process in which the model voltage value calculation unit 10 calculates the model voltage value Vmdl. (Step S1). Next, an estimated voltage calculation value calculation process is performed in which the subtractor 11 calculates the estimated voltage value Vemf_set by subtracting the model voltage value Vmdl from the battery voltage measurement value (step S2).

  Next, a correction value calculation process for calculating a correction value δSOC for calculating the charging rate error by the correction value calculation unit 13 is performed (step S3). Next, the charging rate estimation unit 12 performs a charging rate estimated value calculation process for calculating a charging rate estimated value using the correction value δSOC calculated in step S3 (step S4). When step S4 ends, the charging rate estimation apparatus 1 ends the charging rate calculation process. Note that the charging rate estimation apparatus 1 according to the first embodiment performs the processing flow shown in FIG. 4 for each predetermined period or for each predetermined operation trigger such as engine start.

  From the above description, in the charging rate estimation apparatus 1 according to the first embodiment, the correction value calculation unit 13 calculates the correction value δSOC that is not affected by fluctuations in the estimated electromotive voltage due to the memory effect. Then, the charging rate estimation device 1 corrects the charging rate correction value calculated by the charging rate estimation unit 12 using the correction value δSOC. Thereby, the charging rate estimation apparatus 1 according to the first embodiment can calculate the charging rate estimation value with high accuracy regardless of the presence or absence of the memory effect.

  Here, for example, when the charging rate estimation device 1 calculates the charging rate estimation value at the time of discharging, and the electromotive voltage decreases due to the memory effect, the charging rate estimation unit 12 sets the battery voltage measurement value at which the voltage drop has occurred. Based on this, a charge rate estimation value lower than the original charge rate is calculated. When a system using a secondary battery is operated using the estimated charge rate with such an error, the amount of charge of the secondary battery is still high even though power remains in the secondary battery. It is determined that the battery is insufficient, and a problem occurs that the battery usage area cannot be fully utilized. However, by using the charging rate estimation apparatus 1 according to the first embodiment, the charging rate estimation value having the error as described above is not calculated, so that the usage area of the battery can be fully utilized.

  Further, in the charging rate estimation apparatus 1 according to the first embodiment, the correction value δSOC is calculated only by the data shift process. This data shift process is a relatively light process. Therefore, in the charging rate estimation apparatus 1 according to the first embodiment, it is possible to reduce the amount of calculation necessary for calculating the correction value δSOC.

  Further, in the charging rate estimation apparatus 1 according to the first embodiment, when the correction value δSOC is calculated in the correction value calculation unit 13, it is necessary to collect data constituting the current charging / discharging curve over the entire charging rate estimation value. There is no. Therefore, the charging rate estimation apparatus 1 according to the first embodiment can calculate the correction value δSOC in the usage state of a general secondary battery that is used without completely charging and discharging the secondary battery. Thereby, the charging rate estimation apparatus 1 according to the first embodiment can increase the update frequency of the correction value δSOC and keep the error of the charging rate estimation value with respect to the actual charging rate small.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Charge rate estimation apparatus 10 Model voltage value calculation part 11 Subtractor 12 Charge rate estimation part 13 Correction value calculation part

Claims (5)

A charge rate estimation method for a secondary battery that estimates a charge rate of a secondary battery based on a charge / discharge current measurement value, a battery voltage measurement value, and a temperature measurement value obtained by measuring the secondary battery,
Based on the measured charge / discharge current value and the measured temperature value, a model voltage value indicating the magnitude of a voltage fluctuation component generated by a factor other than the electromotive voltage of the secondary battery is calculated.
Subtracting the model voltage value from the battery voltage measurement value to calculate an electromotive voltage estimated value that is an estimated value of the electromotive voltage of the secondary battery,
Calculating a charge rate estimation value indicating a charge rate of the secondary battery estimated based on the charge / discharge current measurement value, the temperature measurement value, and the battery voltage measurement value;
An initial charge / discharge curve indicating a relationship between an initial charge rate estimated value and an initial electromotive force estimated value calculated before the use of the secondary battery, and the charge rate estimated value calculated during a predetermined period after the start of use And a correction value based on the difference between the current charge / discharge curve indicating the relationship between the estimated voltage and the estimated voltage,
A charging rate estimation method for a secondary battery, wherein the charging rate estimation value is corrected based on the correction value.   The current charging / discharging curve is shifted in a direction in which the estimated charging rate is increased or decreased, and a predetermined number or more of a plurality of data constituting the current charging / discharging curve is matched with the initial charging / discharging curve. The charging rate estimation method of the secondary battery of Claim 1 which outputs the shift amount of the said present charging / discharging curve as said correction value.   The secondary battery charge rate estimation method according to claim 1, wherein the correction value is calculated using data relating to a part of the current charge / discharge curve. A model voltage value for calculating a model voltage value indicating a magnitude of a voltage fluctuation component generated by a factor other than an electromotive voltage of the secondary battery based on a measured value of charge / discharge current of the secondary battery and a measured temperature value of the secondary battery A calculation unit;
A subtractor for subtracting the model voltage value from the battery voltage measurement value of the secondary battery to calculate an estimated electromotive voltage value that is an estimated value of the electromotive voltage of the secondary battery;
A charge rate estimator that calculates a charge rate estimate value indicating a charge rate of the secondary battery estimated based on the charge / discharge current measurement value, the temperature measurement value, and the battery voltage measurement value of the secondary battery;
An initial charge / discharge curve indicating a relationship between the charge rate estimated value calculated before the start of use of the secondary battery and the electromotive voltage estimated value, and the charge rate estimated value calculated during a predetermined period after the start of use. A correction value calculation unit that calculates a correction value based on the difference between the current charge / discharge curve indicating the relationship between the estimated voltage and the estimated electromotive voltage, and
The charging rate estimation unit is a charging rate estimation device that corrects the charging rate estimation value calculated based on the correction value. The charge / discharge current measurement value, battery voltage measurement value, and temperature measurement value obtained by measuring the secondary battery, which are executed in the calculation unit, are acquired from the outside, and the charge rate of the secondary battery is estimated based on the acquired measurement value Rechargeable battery charging rate estimation program,
A Dell voltage value calculation process for calculating a model voltage value indicating a magnitude of a voltage fluctuation component generated by a factor other than an electromotive voltage of the secondary battery based on the charge / discharge current measurement value and the temperature measurement value;
A subtraction process for subtracting the model voltage value from the battery voltage measurement value to calculate an electromotive voltage estimated value that is an estimated value of the electromotive voltage of the secondary battery;
A charge rate estimation process for calculating a charge rate estimate value indicating a charge rate of the secondary battery estimated based on the charge / discharge current measurement value, the temperature measurement value, and the battery voltage measurement value;
An initial charge / discharge curve indicating a relationship between the charge rate estimated value calculated before the start of use of the secondary battery and the electromotive voltage estimated value, and the charge rate estimated value calculated during a predetermined period after the start of use. And a correction value calculation process for calculating a correction value based on the difference between the current charge / discharge curve indicating the relationship between the estimated voltage and the estimated voltage,
In the correction value calculation process, a charging rate estimation program for a secondary battery that corrects the charging rate estimation value based on the correction value.

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