JP2010127729A - Deterioration estimation method and device of battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deterioration estimation method and a device of a battery capable of estimating accurately deterioration of a battery capacity, and improving calculation accuracy of an SOC (State of charge) by using the estimation result for calculation of the SOC which is a battery charge quantity. <P>SOLUTION: An estimated value R1 of a parameter set in consideration of an electrode reaction and an estimated value R2 of a parameter set in consideration of a diffusion reaction are corrected respectively by SOC-v, and a capacity maintenance rate of a battery 6 is estimated from each of the corrected estimated value R1 of the parameter set in consideration of the electrode reaction and the corrected estimated value R2 of the parameter set in consideration of the diffusion reaction, and the capacity maintenance rate of the battery 6 is estimated by averaging both estimated values. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention belongs to the technical field of a battery deterioration estimation method and apparatus constituted by a plurality of unit cells.

  Conventionally, a secondary battery is represented by an equivalent circuit composed of an electromotive force, an electrolytic solution resistance, a positive and negative electrode resistance, and a capacitor component of the electrode. Only the resistance component is calculated (for example, refer to Patent Document 1).

  In addition, there is a case in which the internal resistance value of each cell is calculated using only the DC resistance component by using the current value and voltage value of each cell accumulated in a plurality of measurements (see, for example, Patent Document 2). ).

In addition, when charging / discharging, there is a battery that measures the internal resistance of a secondary battery by changing one of a current and a voltage in a stepped shape or a rectangular wave shape and obtaining an internal impedance (for example, Patent Documents). 3).
JP 2000-133322 A (page 2-4, full view) JP 2004-28861 A (page 2-9, full view) JP 2006-162283 A (page 2-29, full view)

However, in the prior art, when the DC resistance component is used, the calculation error of the internal resistance is large, and as a result, the SOC (State of charge, hereinafter abbreviated as SOC), which is the battery charge amount calculated using the internal resistance, is calculated. The error was large.
In addition, in the case of using the internal impedance, the internal resistance is accurately measured including a component having a time response delay, but it is difficult to perform the measurement during the operation of the battery.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to accurately estimate the deterioration of the battery capacity, which is used for calculating the SOC that is the battery charge amount, and calculating the SOC. It is an object of the present invention to provide a battery deterioration estimation method and apparatus capable of improving accuracy.

  In order to achieve the above object, the present invention provides a method for estimating deterioration of a battery composed of a plurality of unit cells, wherein an equivalent circuit having parameters that take into account electrode reaction and diffusion reaction is set as an internal resistance component of the battery. Measuring the state of the battery, sequentially estimating the parameters of the equivalent circuit based on the state of the battery and the equivalent circuit, and calculating the open-circuit voltage based on the state of the battery and the parameter and calculating the open-circuit voltage. The estimated SOC value based on the open-circuit voltage is corrected with the estimated parameter value set in consideration of the electrode reaction and the estimated parameter value set in consideration of the diffusion reaction, respectively. A corrected estimate of a parameter set taking into account the electrode reaction and a corrected estimate of a parameter set taking into account the diffusion reaction Estimating the capacity retention et the battery, both estimates are averaged to estimate the capacity maintenance rate of the battery, characterized in that.

  Therefore, in the present invention, the deterioration of the battery capacity can be accurately estimated, and this can be used for calculating the SOC that is the battery charge amount, so that the calculation accuracy of the SOC can be improved.

  Hereinafter, an embodiment for realizing a battery remaining amount estimating method and apparatus according to the present invention will be described based on Example 1 corresponding to the invention according to claims 1 to 6.

First, the configuration will be described.
FIG. 1 is a block diagram illustrating a configuration of a battery device using the battery deterioration estimation method according to the first embodiment.
The battery device 1 according to the first embodiment includes a battery controller 2, a voltage sensor 3, a current sensor 4, a temperature sensor 5, a battery 6, and a load 7.
The battery controller 2 calculates the total capacity (battery capacity) of the battery 6, the SOC that is the battery charge amount, the input / output possible power, and the like.
The voltage sensor 3 measures the battery voltage output from the battery 6.
The current sensor 4 measures the battery current output from the battery 6.
The temperature sensor 5 measures the battery temperature of the battery 6.
The battery 6 is a battery formed by connecting a plurality of unit battery cells. Hereinafter, the battery 6 will be described as the battery 6. In Example 1, a lithium ion battery is taken as an example.

Next, a control block configuration related to battery capacity deterioration estimation provided in the battery controller 2 will be described.
FIG. 2 is a control block diagram relating to battery capacity deterioration estimation of the battery device using the battery deterioration estimation method of the first embodiment.
The battery controller and roller 2 include an equivalent circuit parameter estimation unit 21, a deterioration estimation unit 22, an open circuit voltage SOC calculation unit 23, a current integration SOC calculation unit 24, an averaging calculation unit 25, and an input / output power calculation unit 26.

The equivalent circuit parameter estimation unit 21 obtains parameters of an equivalent circuit, for example, each DC resistance component of the battery and a transient state from the battery voltage measured by the voltage sensor 3 and the battery current measured by the current sensor 4. The capacitor component is obtained and output. Details will be described later.
The deterioration estimation unit 22 estimates the amount of battery capacity deterioration from the equivalent circuit parameters from the equivalent circuit parameter estimation unit 21 and the battery temperature measured by the temperature sensor 5, and outputs the capacity maintenance rate of the battery 6.
The open-circuit voltage SOC calculation unit 23 calculates the open-circuit voltage of the battery 6 as SOC-v (%) based on the equivalent circuit parameter from the equivalent circuit parameter estimation unit 21 and outputs it.

Current integration SOC calculation unit 24 inputs / outputs current from SOC-v (%) from open-circuit voltage SOC calculation unit 23, capacity maintenance rate from degradation estimation unit 22, and battery current measured by current sensor 4. An operation for integrating the minutes is performed, and it is calculated and output as SOC-i (%).
The averaging calculation unit 25 performs an operation of averaging SOC-v from the open circuit voltage SOC calculation unit 23 and SOC-i from the current integration SOC calculation unit 24 to calculate and output SOC (%).
Based on the SOC (%) from the averaging calculation unit 25, the input / output power calculation unit 26 calculates and outputs power that can be input / output by the battery 6. This output is output, for example, to other controls inside the battery controller 2 and to the outside.

Next, details of the equivalent circuit parameter estimation unit 21 will be described.
FIG. 3 is a control block diagram of the equivalent circuit parameter estimation unit of the first embodiment.
The equivalent circuit parameter estimation unit 21 is an adaptive digital filter, and includes a battery calculation unit 211, a battery model 212, an adaptation mechanism 213, and a subtracter 214. It is a filter that self-corrects internal parameters.
The battery calculation unit 211 receives the measured battery current (i (k) inside the equivalent circuit parameter estimation unit 21) as an input to the control system and inputs the measured battery voltage (equivalent circuit parameter estimation). It is a calculation part set in the adaptive digital filter so as to output V (k) inside the unit 21. The battery calculation unit 211 is set to handle actual values.

The battery model 212 is an equivalent circuit that is a model of the battery 6, and adjusts the parameters of the equivalent circuit with the corrected output from the adaptive mechanism 213, and outputs a voltage model estimated value V ^ (k). Furthermore, the parameter of the equivalent circuit is output as the output of the equivalent circuit parameter estimation unit 21. For example, resistance values R0 to R2 and capacitor capacitances C1 and C2. Note that the resistance values R1 and R2 are used for both the symbol indicating resistance and the symbol indicating resistance value for the sake of explanation.
The adaptive mechanism 213 performs output for correcting the calculation content of the battery model 212 in accordance with the deviation calculated by the subtracter 214.
The subtracter 214 calculates the deviation between the output of the battery calculation unit 211, that is, the measured battery voltage V (k) and the voltage model estimated value V ^ (k). (V ^ represents the estimated value of V. Actually, ^ is on V.)

Next, a configuration example of an equivalent circuit set in the battery model 212 will be described.
FIG. 4 is a diagram illustrating an equivalent circuit configuration of the battery model of the first embodiment.
As shown in FIG. 4, the equivalent circuit of the battery model 212 includes an open circuit voltage OCV, resistors R0, R1, R2, and capacitor capacities C1, C2.
Then, the open circuit voltage OCV, the resistor R0, the parallel connection portion of the resistor R1 and the capacitor capacitance C1, and the parallel connection portion of the resistor R2 and the capacitor capacitance C2 are connected in series. Here, the resistor R0 is provided as a resistance of the electrolytic solution in the battery 6. The resistors R1 and C1 are provided as electrode reaction resistors in the battery 6. The resistors R2 and C2 are provided as diffusion resistors in the battery 6.

The operation will be described.
[Battery deterioration, SOC, and power handling]
FIG. 5 is a flowchart showing the flow of calculation processing of the battery capacity SOC and power using the battery deterioration estimation method of the first embodiment, which is executed by the battery controller 2. Each step will be described below.

  In step S1, the battery controller 2 inputs the battery voltage, battery current, and battery temperature measured by the voltage sensor 3, the current sensor 4, and the temperature sensor 5.

  In step S2, the equivalent circuit parameter estimation unit 21 estimates the resistance values R0 to R2 and the capacitor capacities C1 and C2 using an adaptive digital filter.

  In step S3, the open circuit voltage SOC calculation unit 23 estimates the open circuit voltage OCV from the resistance values R0 to R2, the capacitor capacities C1 and C2 estimated in step S1, the measured battery voltage, and the battery current, and the open circuit voltage OCV SOC-v is calculated from the SOC relationship. The relationship between the open circuit voltage OCV and the SOC is prepared in advance by experiments or the like.

In step S4, the deterioration estimating unit 22 calculates a correction coefficient based on the value of SOC-v for the resistance values R1 and R2, and performs correction by multiplying the resistance values R1 and R2. Note that the relationship between the SOC-v and the correction coefficient is prepared by conducting an experiment in advance.
Further, a temperature coefficient according to the battery temperature is calculated, and correction is performed by multiplying this by the resistance values R1 and R2. Note that the relationship between the battery temperature and the temperature coefficient is prepared by conducting experiments in advance.

  In step S <b> 5, the deterioration estimation unit 22 performs an averaging process separately on the resistance values R <b> 1 and R <b> 2 based on the SOC-v value calculated by the open circuit voltage SOC calculation unit 23.

  In step S6, the deterioration estimation unit 22 calculates a capacity maintenance rate based on the calculated resistance values R1 and R2. The relationship between the resistance values R1 and R2 and the capacity maintenance ratio is prepared by conducting experiments in advance.

  In step S7, the deterioration estimating unit 22 performs an operation of averaging the capacity maintenance ratio calculated based on the resistance value R1 and the capacity maintenance ratio calculated based on the resistance value R2.

  In step S8, the current integration SOC calculation unit 24 calculates the SOC by current integration from the capacity maintenance rate.

  In step S9, the averaging calculator 25 performs an operation of averaging SOC-v calculated from the parameters of the equivalent circuit and SOC-i calculated from the current integration.

  In step S10, the input / output power calculation unit 26 calculates input / output possible power from the SOC after the averaging process.

  In step S11, for example, based on an ignition signal or the like, it is determined whether the driving of the vehicle is stopped. If the driving is stopped, the process is terminated, and if the driving is continued, the process returns to step S1.

[Battery degradation and improvement in SOC estimation accuracy]
FIG. 6 is a diagram showing the current and voltage characteristics of the battery.
In FIG. 6, the right side is during charging and the left side is during discharging. For example, in the case of a battery used for driving a vehicle, charging / discharging is repeated.
In this case, the current-voltage characteristics of the battery 6 are as shown in FIG. 6, and the internal resistance increases due to deterioration, so that the terminal voltage decreases and the performance decreases. That is, the inclination increases. Furthermore, the capacity of the entire battery is reduced.

For example, a line 101 in FIG. 6 indicates a state of 5 Ah when new, and a line 102 in FIG. 6 indicates a state of 4 Ah when deteriorated. The total capacity is reduced to 80% compared to the new product. This is a capacity maintenance rate of 80%.
From the comparison of the lines 101 and 102, it can be seen that the inclination increases due to deterioration.
Thus, the deterioration of the battery appears as a decrease in the battery capacity and an increase in the internal resistance, and the decrease in the battery capacity is important in calculating the SOC obtained by integrating the current.
In the first embodiment, the deterioration of the battery is accurately estimated.
Note that the battery controller 2 inputs sensor values for the battery voltage, battery current, and battery temperature used for estimating the deterioration of the battery, which will be described below, as the process of step S1.

(Equivalent circuit parameter estimation)
Since the equivalent circuit parameter estimation unit 21 includes the equivalent circuit shown in FIG. 4 as the battery model 212, the calculation is performed with a model closer to the actual state including the transient state of the battery 6. In particular, the setting of the resistors R1 and R2 that greatly affect when the battery 6 deteriorates improves the accuracy of estimation of deterioration.
In the equivalent circuit parameter estimation unit 21, the deviation between the battery voltage V (k) measured as the output of the battery calculation unit 211 set as an actual value and the voltage model estimation value V ^ (k) is reduced. As described above, the adaptive mechanism 213 changes the parameters of the battery model 212. Since this is sequentially changed during the calculation, it is a sequential state estimation, and the parameters of the battery model 212 are very well understood from the actual deterioration state. (V ^ represents the estimated value of V. Actually, ^ is on V.)
The parameters of the battery model 212 are output, and the subsequent calculation is performed to further improve the accuracy of estimating the deterioration state of the battery 6. In addition, the process of the equivalent circuit parameter estimation part 21 is performed as a process of step S2.

(SOC-v calculation)
FIG. 7 is a graph showing the relationship between the open-circuit voltage and SOC-v in Example 1.
Next, in order to estimate deterioration, the SOC-v required in the first embodiment is calculated together with the parameters of the equivalent circuit.
The degradation estimation unit 22 calculates the open circuit voltage OCV from the parameters R0 to R2, C1, C2 from the equivalent circuit parameter estimation unit 21, the battery voltage, and the battery current.
Then, SOC-v is calculated from the open circuit voltage OCV using the relationship of FIG. FIG. 7 is obtained in advance by experiments or the like.

(Calculation of capacity maintenance rate)
Next, based on the parameters of the equivalent circuit parameter estimation unit 21 calculated in this way and the SOC-v, the degradation estimation unit 22 estimates the capacity maintenance ratio indicating the degree of degradation as the processing of steps S4 to S7. Calculate the value. This will be described below.
FIG. 8 is a graph showing the relationship between the correction coefficient of the resistor R1 and the battery charge amount in the first embodiment. FIG. 9 is a graph showing the relationship between the correction coefficient of the resistor R2 and the battery charge amount in the first embodiment. FIG. 10 is a graph showing the relationship between the temperature and the temperature coefficient of resistance in Example 1.
Since the resistances R1 and R2, which are internal resistances, vary depending on the state of the SOC, this characteristic is obtained in advance as shown in FIGS. 8 and 9, and the calculated resistance values of the resistances R1 and R2 are calculated with respect to the SOC− A correction coefficient is calculated from the relationship shown in FIGS. 8 and 9 from the value of v. Then, the resistance values of the resistors R1 and R2 are divided (divided) by the correction coefficient (step S4).

Since the resistance value is affected by the temperature, the resistance value of the resistor R1 is further corrected by the temperature coefficient calculated from the Arrhenius law as shown in FIG. 10 (step S4).
For example, when 25 ° C. is used as a reference for the temperature coefficient, the temperature coefficient is calculated by the following formula.
(Formula 1)
Temperature coefficient = exp (-U / kT) / exp (-U / k × 298)
Where T is the battery temperature (K), U is the electrode material activation energy (eV), 1eV is 1.602 × 10-19 (J), and k = 1.380 × 10-23 (J / K). To do.
The resistance R1, which is an electrode reaction resistance, is greatly affected by temperature. Therefore, the accuracy is further improved by performing the correction by the temperature coefficient in this way.

After correcting the resistors R1 and R2 in this way, the resistance values of the resistors R1 and R2 are averaged.
The resistance values of the resistors R1 and R2 are sequentially estimated and become a plurality of values. Moreover, since it changes in the SOC range, the values obtained by both are averaged (step S5).
FIG. 11 is a graph showing the relationship between the resistance R1 and the SOC in the first embodiment. FIG. 12 is a graph showing the relationship between the resistance R2 and the SOC in the first embodiment.
Since the resistance values of the resistors R1 and R2 vary depending on the SOC, when the SOC-v can be measured accurately, the influence of deterioration can be well understood as shown in FIGS. The resistances R1 and R2 after estimation and correction in the large value range A (FIGS. 11 and 12) are weighted by weighted average.
For example, three points are extracted in the range A and three points are extracted in the range B, such that the range A: the range B = 3: 2.

Further, when there is an error in SOC-v, the resistance R1, R2 after estimation is performed in the range B (FIGS. 11 and 12) in which the change in value is smaller than the range A, and the weights are weighted by the weighted average. Make it bigger.
For example, three points are extracted in the range A and three points are extracted in the range B, such that the range A: the range B = 2: 3.
Further, when the SOC range to be used is limited, the range B may be divided and estimated with a frequently used SOC range.

  Moreover, as the actual use of the SOC of the battery 6, the region where the SOC is extremely reduced from the viewpoint of maintaining the function is not frequent, and therefore the range B is a frequently used region. For this reason, the range B having a high frequency may be weighted. The accuracy is improved from the frequency.

  In addition, as shown in FIGS. 11 and 12, the relationship between the SOC and the resistance value can be divided into a range A having a large inclination and a range B having a small inclination. In the range A, the inclination is large, that is, the resistance value changes greatly with respect to the change in SOC. Therefore, the difference in resistance between the new state indicated by reference numerals 103 and 105 in FIGS. 11 and 12 and the deteriorated state indicated by reference numerals 104 and 106 increases. As a result, the estimation is performed in consideration of the deterioration state. However, when the SOC value error is large, the slope of the range B is smaller, that is, the resistance value changes smaller with respect to the change of the SOC. Therefore, the difference in resistance between the new state indicated by reference numerals 103 and 105 in FIGS. 11 and 12 and the deterioration state indicated by reference numerals 104 and 106 is reduced. As a result, estimation with less influence of error is performed. Which is selected is preferably determined by the state of the SOC value.

After the resistances R1 and R2 are corrected in this way, the capacity maintenance ratio is calculated from the resistance values of the resistances R1 and R2 (step S6).
FIG. 13 is a graph showing the relationship between the resistance R1 and the capacity retention rate of the battery in Example 1. FIG. 14 is a graph showing the relationship between the resistance R2 and the capacity retention rate of the battery in Example 1.
The data shown in FIGS. 13 and 14 are obtained by performing system identification using the AC impedance measurement and the equivalent circuit shown in FIG. 4 as a model with the battery 6 having a different number of charge / discharge cycles and a constant temperature and SOC. R1 and R2 are obtained, and the relationship between the respective capacity maintenance ratios and the resistances R1 and R2 is created as shown in FIGS.
In FIGS. 13 and 14, the SOC is 50% and the temperature is 25 ° C. This SOC and temperature are examples.
Thus, since the resistance values of the resistors R1 and R2 that are greatly affected by the deterioration of the battery 6 can be calculated separately, this relationship can be determined more accurately, so that the estimation accuracy of the capacity maintenance rate is improved.

If the capacity retention rate can be estimated in this way, the capacity retention rates due to the resistors R1 and R2 are averaged. This is performed by the process of step S7 by the deterioration estimation unit 22.
Then, SOC-i is calculated from the capacity maintenance rate by current integration. This is performed by the current integration SOC calculation unit 24 in the process of step S8.
FIG. 15 is an explanatory diagram of a state of calculating SOC-i by current integration in the first embodiment.
The current integration amount is calculated from the current measured by the current sensor 4. Referring to FIG. 15, the plus side of the horizontal axis is charged, the minus side is discharged, and the horizontal axis is time. Then, the time of the charging range 201 and the charged current value, the time of the discharging range 202 and the discharged current value, the time of the charging range 203 and the charged current value, and then the time of the discharging range 204 and the discharged current Integration is performed as a value to calculate the current integration amount.
That is, the following formula is calculated.

  (Formula 2)

  Current integrated amount (Ah) = − (Current integrated value in range 201) + (Current integrated value in range 202) + (Current integrated value in range 203) + (Current integrated value in range 204)

Then, SOC-i (%) is calculated.
Since the full capacity of the battery 6 is a value determined by the specifications of the battery 6, if the capacity maintenance rate can be accurately estimated, the SOC-i can be calculated with high accuracy.
Specifically, SOC-i is calculated from the following equation.

  (Formula 3)

  SOC-i (%) = initial SOC + (current integrated amount / (full capacity × capacity maintenance ratio))

  In the above equation, the full capacity is a value of how many amperes of current can flow for an SOC of 100% to 0%. Here, a new value is used, and the SOC calculated at the time of starting the system is used as the initial SOC of the above equation.

When the SOC-i is calculated in this way, the SOC-v calculated based on the parameters of the equivalent circuit, the measured battery voltage, and the battery current in the process of step S9 of the averaging calculation unit 25, and the current integration are calculated. The SOC-i calculated from the above is averaged.
In this averaging, if there is a difference in reliable values, a weighted average may be performed.

The input / output power calculator 26 calculates the power that can be input / output by the process of step S10. At this time, it is preferable that the battery controller 2 stores the degree of decrease in SOC during normal use and used for the calculation.
The SOC and electric power estimated with high accuracy in this way are very useful when used for controlling the battery of the battery controller 2 and displaying the travelable distance to the driver in the vehicle.

In order to clarify the operation of the first embodiment, a description will be added.
FIG. 16 is an explanatory diagram showing an example of an equivalent circuit of a battery. FIG. 17 is an explanatory diagram showing a characteristic example of the current and voltage of the battery. FIG. 18 is an explanatory diagram showing an example of internal resistance and capacity retention rate.
In order to estimate the SOC in consideration of deterioration, it is conceivable to set an equivalent circuit as shown in FIG. Then, several currents and voltages are measured in the current range determined as shown in FIG. 17, the inclination is obtained as the internal resistance, and the relationship between the internal resistance and the capacity maintenance ratio as shown in FIG. 18 is calculated. It is conceivable to estimate the battery capacity after deterioration.

However, in the equivalent circuit shown in FIG. 16, since the delay in time response is not taken into account, the error of the internal resistance becomes large. When calculating the relationship of FIG. 18, the error of the internal resistance due to the influence of the charge / discharge current, temperature, and SOC increases, and the error of the estimated capacity maintenance rate also increases.
The first embodiment is advantageous in that the internal resistance can be accurately estimated and the capacity maintenance rate can be accurately estimated.

  Explain the effect. In the battery deterioration estimation method according to the first embodiment, the effects listed below can be obtained.

  (1) A method for estimating deterioration of a battery 6 composed of a plurality of unit cells, wherein a battery model 212 having parameters R1 and R2 taking into account electrode reactions and diffusion reactions is set as an internal resistance component of the battery 6, and the battery 6 The battery voltage and battery current of the battery 6 are measured, the parameters of the battery model 212 are sequentially estimated based on the battery voltage and battery current of the battery 6 and the battery model 212, and the open circuit voltage OCV is determined based on the state of the battery 6 and the parameters R1 and R2. SOC-v is calculated through calculation of the parameter, and the estimated value R1 of the parameter set in consideration of the electrode reaction and the estimated value R2 of the parameter set in consideration of the diffusion reaction are respectively corrected by the SOC-v. The corrected estimate R1 of the parameter set in consideration of the electrode reaction and the corrected estimate R2 of the parameter set in consideration of the diffusion reaction Since the capacity maintenance rate of the battery 6 is estimated from each of the two values and the estimated values are averaged to estimate the capacity maintenance rate of the battery 6, it is possible to accurately estimate the deterioration of the battery capacity, which is used to calculate the SOC that is the battery charge amount. It is possible to improve the calculation accuracy of the SOC.

  (2) In the above (1), the change in the correction amount of the parameters R1 and R2 with respect to the SOC-v is divided into a range A which is a steep region and a range B which is a gradual region. Since the values R1 and R2 are averaged and used as a parameter correction, R1 and R2 taking into account the time response set as the internal resistance of the battery 6 can be accurately estimated, thereby improving the estimation accuracy of the capacity maintenance rate.

  (3) In the above (2), the weighted average weighted over the range B, which is a region where the change in the correction amount of the parameters R1 and R2 with respect to the SOC-v is gradual, is used to correct the parameters R1 and R2. The correction values of the resistance values R1 and R2 can be obtained by reducing the number, thereby improving the estimation accuracy of the capacity maintenance rate.

  (4) In the above (1) to (3), the battery temperature is measured as the measurement of the state of the battery 6, and the temperature correction is performed on the estimated value R1 of the parameter set in consideration of at least the electrode reaction. Further, by improving the accuracy of the estimated value R1 of the parameter having a large influence of deterioration, the accuracy of estimating the capacity maintenance rate can be further improved.

  (5) In the above (1) to (4), SOC-i is calculated based on the estimated capacity maintenance rate of the battery 6 and the current integrated amount obtained by integrating the charge / discharge of current, and SOC-v Since the SOC is estimated by averaging the SOC-i, the estimation accuracy of the SOC can be improved.

  (6) A deterioration estimation device for the battery 6 composed of a plurality of unit cells, in which the voltage sensor 3 and the current sensor 4 for measuring the state of the battery 6 and the electrode reaction and the diffusion reaction are considered in the internal resistance component of the battery 6 The equivalent battery parameter estimation unit 21 that sequentially estimates the parameters R0 to R2, C1, and C2 of the battery model 212 based on the state of the battery 6 and the battery model 212 is set. 6 based on the state 6 and the parameters R1 and R2, the open-circuit voltage SOC calculation unit 23 for calculating the SOC-v through the calculation of the open-circuit voltage OCV, the estimated value R1 of the parameter set in consideration of the electrode reaction and the diffusion The estimated value R2 of the parameter set in consideration of the reaction is corrected by SOC-v, and the corrected estimated value R1 of the parameter set in consideration of the electrode reaction Deterioration estimation in which the capacity maintenance rate of the battery 6 is estimated from each of the corrected estimated values of the parameter R2 set in consideration of the mixed reaction, and both estimated values are averaged to estimate the capacity maintenance rate of the battery 6 Since the unit 22 is provided, the deterioration of the battery capacity can be accurately estimated, and this can be used for calculating the SOC that is the battery capacity, thereby improving the calculation accuracy of the SOC.

  As described above, the method for estimating the remaining amount of the battery according to the present invention has been described based on the first embodiment. However, the specific configuration is not limited to these embodiments, and the present invention relates to each claim of the claims. Design changes and additions are allowed without departing from the scope of the invention.

For example, although the adaptive circuit filter is provided in the equivalent circuit parameter estimation unit in the first embodiment, it may be a Kalman filter.
For example, the control block configuration in the first embodiment may be configured by a circuit (hardware), a program (software), or a combination.

It is a block diagram which shows the structure of the battery apparatus using the deterioration estimation method of the battery of Example 1. FIG. FIG. 3 is a control block diagram regarding battery capacity deterioration estimation of the battery device using the battery deterioration estimation method according to the first embodiment. FIG. 3 is a control block diagram of an equivalent circuit parameter estimation unit according to the first embodiment. FIG. 3 is a diagram illustrating an equivalent circuit configuration of the battery model according to the first embodiment. 3 is a flowchart illustrating a flow of a calculation process of a battery charge amount SOC and power using the battery deterioration estimation method according to the first embodiment. It is a figure which shows the characteristic of the electric current and voltage of a battery. It is a graph which shows the relationship between the open circuit voltage in Example 1, and SOC-v. It is a graph which shows the relationship between the correction coefficient of resistance R1 in Example 1, and a battery charge amount. It is a graph which shows the relationship between the correction coefficient of resistance R2 in Example 1, and a battery charge amount. It is a graph which shows the relationship between the temperature in Example 1, and the temperature coefficient of resistance value. FIG. 3 is a graph showing the relationship between resistance R1 and SOC in Example 1. It is a graph which shows the relationship between resistance R2 and SOC in Example 1. FIG. It is a graph which shows the relationship between resistance R1 in Example 1 and the capacity | capacitance maintenance factor of a battery. It is a graph which shows the relationship between resistance R2 and the capacity | capacitance maintenance factor of a battery in Example 1. FIG. It is explanatory drawing of the state which calculates SOC-i by the current integration in Example 1. FIG. It is explanatory drawing which shows the example of an equivalent circuit of a battery. It is explanatory drawing which shows the example of a characteristic of the electric current and voltage of a battery. It is explanatory drawing which shows the example of internal resistance and a capacity | capacitance maintenance factor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery apparatus 2 Battery controller 21 Equivalent circuit parameter estimation part 211 Battery calculation part 212 Battery model 213 Adaptation mechanism 214 Subtractor 22 Degradation estimation part 23 Open-circuit voltage SOC calculation part 24 Current integration SOC calculation part 25 Averaging calculation part 26 Input / output power Arithmetic unit 3 Voltage sensor 4 Current sensor 5 Temperature sensor 6 Battery 7 Load

Claims (6)

A battery deterioration estimation method comprising a plurality of unit cells,
Set an equivalent circuit having parameters that take into account electrode reaction and diffusion reaction in the internal resistance component of the battery,
Measuring the state of the battery;
Based on the state of the battery and the equivalent circuit, sequentially estimate the parameters of the equivalent circuit,
Based on the state of the battery and the parameter, through the calculation of the open circuit voltage, to calculate an estimated SOC value based on the open circuit voltage,
The estimated value of the parameter set in consideration of the electrode reaction and the estimated value of the parameter set in consideration of the diffusion reaction are respectively corrected with the SOC estimated value based on the open circuit voltage,
The capacity maintenance rate of the battery is estimated from the corrected estimated value of the parameter set in consideration of the electrode reaction and the corrected estimated value of the parameter set in consideration of the diffusion reaction, and both estimated values are obtained. The capacity maintenance rate of the battery was estimated by averaging,
A battery deterioration estimation method characterized by the above. The battery deterioration estimation method according to claim 1,
The change in the correction amount of the parameter with respect to the estimated SOC value based on the open circuit voltage is divided into a steep region and a gentle region, and the parameter value corrected in each region is averaged to obtain the correction of the parameter.
A battery deterioration estimation method characterized by the above. The battery deterioration estimation method according to claim 2,
A weighted average is applied to a region where the change in the correction amount of the parameter with respect to the SOC estimated value based on the open-circuit voltage is gentle, and the correction of the parameter is performed.
A battery deterioration estimation method characterized by the above. The battery deterioration estimation method according to any one of claims 1 to 3,
Measuring the battery temperature as a measure of the state of the battery,
Temperature correction was performed on the estimated parameter value set in consideration of at least the electrode reaction.
A battery deterioration estimation method characterized by the above. The current estimation based on the estimated capacity maintenance rate of the battery and the current integration amount obtained by integrating the charge / discharge of the current by the deterioration estimation method according to any one of claims 1 to 4. Based on the estimated SOC,
The SOC estimated value based on the open circuit voltage and the SOC estimated value based on the current integration were averaged to estimate the SOC.
A method for estimating the remaining amount of a battery. A battery deterioration estimation device composed of a plurality of unit cells,
Battery state measuring means for measuring the state of the battery;
An equivalent circuit parameter estimation means for sequentially estimating the parameters of the equivalent circuit based on the state of the battery and the equivalent circuit, wherein an equivalent circuit having a parameter that takes into account an electrode reaction and a diffusion reaction is set in the internal resistance component of the battery; ,
Means for calculating an estimated SOC value based on an open circuit voltage based on the state of the battery and the parameter and calculating an open circuit voltage;
Means for correcting an estimated value of a parameter set in consideration of an electrode reaction and an estimated value of a parameter set in consideration of a diffusion reaction, respectively, with an SOC estimated value based on an open circuit voltage;
Capacity maintenance rate estimating means for estimating the capacity maintenance rate of the battery from each of the corrected estimated value of the parameter set in consideration of the electrode reaction and the corrected estimated value of the parameter set in consideration of the diffusion reaction When,
Averaging means for averaging both estimated values to estimate the capacity maintenance rate of the battery;
With
A battery deterioration estimation device characterized by the above.

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