Estimation device

Abstract

Improve the estimation accuracy of SOH. [Solution] The estimation device 1 comprises a current integration unit 11, a SOC estimation unit 12, and a SOH estimation unit 13. The current integration unit 11 calculates multiple time points t during the charging and discharging of the battery 5. n Using the current value I of battery 5 measured at time t0, the measurement was performed from time t0 to time t n The current integration value ΔQ up to t is calculated. The SOC estimation unit 12 calculates the current integration value ΔQ up to t. n Using the current value I and terminal voltage value V of battery 5 measured at each measurement time t n The SOC estimate is calculated. The SOH estimation unit 13 uses a dataset containing three or more points, preferably five or more points, including the integrated current value ΔQ and the SOC estimate, to estimate the SOH of the battery 5 based on a regression line calculated by the least squares method.

Description

[Technical Field]

[0001] This invention relates to an estimation device. [Background technology]

[0002] Batteries are used to supply power to the vehicle's drive source, such as the motor. Batteries gradually deteriorate with repeated charging and discharging, and their full charge capacity decreases. State of Health (SOH) is used as a value to indicate the health of the battery. State of Health (SOH) is a necessary element for proper control of battery charging and discharging, but it cannot be measured directly. Therefore, a method has been proposed to estimate SOH using values ​​that can be measured from the battery (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2014 / 083856 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] One method for estimating SOH involves a calculation based on the change in SOC (State of Charge) and the integrated current value between two points in time. However, since the change in SOC is calculated using an estimated SOC, it may be affected by the estimation error of SOC. If the estimation accuracy of SOH is not good, it may be necessary to use a larger battery to provide a large safety margin in the battery charge / discharge control range, which may affect cost and the layout of the in-vehicle equipment. In estimation devices, there is a need to reduce the impact of estimation errors in SOC and improve the estimation accuracy of SOH. [Means for solving the problem]

[0005] The present invention is an estimation device for estimating the soundness of a battery, including an integrated value calculation unit that calculates an integrated current value from the start of measurement to each measurement time point using current values of the battery measured at a plurality of time points during charging and discharging of the battery, a SOC estimation unit that calculates a SOC estimated value at each measurement time point using the current value and the terminal voltage value of the battery measured at the plurality of time points, and a soundness estimation unit that estimates the soundness based on a regression line calculated by the least squares method using three or more data sets including the integrated current value and the SOC estimated value at each measurement time point.

Advantages of the Invention

[0006] According to the present invention, it is possible to reduce the influence of the estimation error of the SOC and improve the estimation accuracy of the SOH.

Brief Description of the Drawings

[0007] [Figure 1] It is a block diagram showing the configuration of the estimation device according to the embodiment. [Figure 2] It is a conceptual diagram explaining the relationship between the integrated current value, the SOC, and the SOH. [Figure 3] It is a diagram showing an example of calculation of the SOH. [Figure 4] It is a flowchart showing the processing flow of the estimation device during the running of the vehicle. [Figure 5] It is a block diagram showing the configuration of the estimation device according to Modification 1. [Figure 6] It is a diagram showing an example of calculation of the SOH according to Modification 1. [Figure 7] It is a block diagram showing the configuration of the estimation device according to Modification 2. [Figure 8] It is a flowchart showing the processing flow of the estimation device according to Modification 2.

Modes for Carrying Out the Invention

[0008] Hereinafter, an estimation device according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a block diagram showing the configuration of the estimation device 1 according to an embodiment. The estimation device 1 can be installed in a vehicle such as an electric vehicle or a hybrid electric vehicle that can be driven by power supplied from the battery 5. Battery 5 is a rechargeable secondary battery, and can be a lithium-ion battery, for example, but other types of batteries 5 may also be used. Battery 5 supplies power to the electric motor that drives the vehicle by discharging, and is charged by regenerative energy from the electric motor when the vehicle is braking. Battery 5 can also be charged by external charging equipment such as a fast charger or a household outlet.

[0009] As shown in Figure 1, a current sensor 6 and a voltage sensor 7 are connected to the battery 5. The current sensor 6 measures the current flowing through the battery 5. The voltage sensor 7 measures the terminal voltage of the battery 5. The current sensor 6 and voltage sensor 7 measure the current and terminal voltage at a predetermined sampling period while the vehicle is running (from the time the vehicle's ignition is turned ON to OFF). The estimation device 1 is connected to the current sensor 6 and voltage sensor 7 by wire or wireless. The estimation device 1 receives the current sensor 6 and voltage sensor 7 at each time point t n The measured current value I and terminal voltage value V are input sequentially.

[0010] The estimation device 1 uses the current value I and terminal voltage value V of the battery 5, which are input while the vehicle is running, to estimate the State of Health (SOH) of the battery 5 in real time. SOH represents the ratio of the full charge capacity FCC at the time of degradation (FCC / FCC0) to the full charge capacity of battery 5 when new (hereinafter referred to as "initial full charge capacity FCC0"), and serves as an indicator for determining the degradation state of battery 5. The estimation device 1 can be composed of, for example, an ECU (Electronic Control Unit) installed in a vehicle. Although not shown in the diagram, the ECU consists of a processor such as a CPU and memory such as ROM and RAM. The memory stores various programs that are executed by the estimation device 1, and the functional configuration shown in Figure 1 is realized when the processor executes these programs.

[0011] While a detailed explanation is omitted, the ECU may perform various processes using the SOH in addition to the SOH estimation process. For example, the ECU may perform charge / discharge control of the battery 5 based on the SOH, or calculate the vehicle's remaining driving range from the SOH and perform driving control of the vehicle. Alternatively, the ECU may output the estimated SOH externally, and an external control device may perform processing using the SOH. Alternatively, the estimation device 1 may be a computer located outside the vehicle. In this case, the estimation device 1 located outside the vehicle may, for example, communicate with an ECU located inside the vehicle to obtain the measured values ​​of the current sensor 6 and the voltage sensor 7.

[0012] As shown in Figure 1, the estimation device 1 comprises a current integration unit 11, a SOC estimation unit 12, and a SOH estimation unit 13 (health estimation unit) as its functional configuration. The estimation device 1 also includes a storage unit 14, which is composed of memory. The storage unit 14 stores the data necessary for processing each functional configuration, and also temporarily stores the processing results of each functional configuration.

[0013] The current integrating unit 11 calculates multiple time points t measured by the current sensor 6 while the vehicle is running and the battery 5 is charging and discharging. n The integrated current value ΔQ is calculated using the current value I. The current integration unit 11 calculates from the start time t0 of measurement of the current sensor 6 to each measurement time t n The integrated current value ΔQ is calculated by integrating the current values ​​I up to a certain point. The current integration unit 11 receives a new time point t from the current sensor 6. nEach time a current value I is input, a calculation is performed, and the calculated integrated current value ΔQ is stored in the storage unit 14.

[0014] The SOC estimation unit 12 estimates the State of Charge (SOC), which is the charge level of the battery 5, while the vehicle is running and the battery 5 is being charged and discharged. The SOC estimation unit 12 can estimate the State of Charge (SOC) using a known estimation method with respect to the current value I measured by the current sensor 6 and the terminal voltage value V measured by the voltage sensor 7. One known estimation method is one that uses the overvoltage η of the battery 5. The SOC estimation unit 12 estimates the overvoltage η of the battery 5 using an estimation method that uses an equivalent circuit model such as a Kalman filter, with respect to the current value I and the terminal voltage value V. The SOC estimation unit 12 calculates the open circuit voltage (OCV) of the battery by subtracting the overvoltage η from the terminal voltage value V. The SOC estimation unit 12 obtains an estimated SOC value by converting the open circuit voltage to SOC based on known SOC-OCV characteristics. The SOC estimation unit 12 obtains new time point t from the current sensor 6 and the voltage sensor 7. n Each time a measurement value is input, an estimation is performed, and the estimated SOC value, which is the estimation result, is temporarily stored in the storage unit 14.

[0015] As shown in Figure 1, in the memory unit 14, the current integration value ΔQ calculated by the current integration unit 11 and the SOC estimate value estimated by the SOC estimation unit 12 are combined at measurement time t n It is stored as a single linked dataset DS. The SOH estimation unit 13 uses multiple time points t stored in the memory unit 14. n We will use the DS dataset to estimate SOH. The SOH estimation unit 13 estimates three or more time points, preferably five or more. n We perform estimation using the DS dataset in [location]. In other words, the SOH estimation unit 13 acquires the accumulated dataset DS when at least three, preferably five or more, dataset DS are accumulated in the storage unit 14 and starts estimating the SOH. After estimating the first SOH, the SOH estimation unit 13 performs SOH estimation each time a new dataset DS is stored in the storage unit 14. Specifically, the SOH estimation unit 13 calculates a regression line using the least squares method with the integrated current value ΔQ of the dataset DS and the estimated SOC. The SOH estimation unit 13 calculates the estimated SOH value by dividing the slope a of the regression line by the initial full charge capacity FCC0 of the battery 5.

[0016] Figure 2 illustrates the relationship between the integrated current value ΔQ and SOC and SOH. Figure 2 shows the state in which the same amount of current is passed through battery 5, both when new and when degraded, from time t0 to time t6. Figure 2(a) is a graph showing the change in the integrated current value ΔQ, and Figure 2(b) is a graph showing the change in SOC. Figure 2(c) is a distribution plot with the integrated current value ΔQ from time t0 to time t6 plotted on the y axis (vertical axis) and SOC on the x axis (horizontal axis). In Figure 2, the data for battery 5 when new is shown with a dashed line, and the data for battery 5 when it has deteriorated is shown with a solid line. Also, the SOC in Figure 2 represents the true value without estimation error.

[0017] As shown in Figures 2(a) and 2(b), the State of Charge (SOC) of battery 5 increases in accordance with the increase in the integrated current value ΔQ from time t0 to time t6. Here, as battery 5 degrades, its full charge capacity FCC gradually decreases from its initial full charge capacity FCC0. Therefore, when the same amount of current flows, the SOC rises faster when battery 5 is degraded (solid line in Figure 2(a)) than when it is new (dashed line in Figure 2(a)). In other words, when battery 5 is degraded, the change in SOC over the same period of time is greater than when it is new. That is, the change in the SOC of battery 5 corresponds to the SOH (FCC / FCC0) of battery 5.

[0018] Figure 2(c) shows a straight line connecting the points plotted between the integrated current value ΔQ and SOC when the device is new and when it is degraded. As shown in Figure 2(c), the slope 'a' of the straight line differs between a new battery 5 (dashed line in the figure) and a degraded battery 5 (solid line in the figure). The slope 'a' of the straight line corresponds to the State of Health (FCC / FCC0) of battery 5. In other words, the State of Health can be estimated by determining the slope 'a' of the straight line plotted with the integrated current value ΔQ and the State of Charge (SOC).

[0019] In this embodiment, SOH is estimated using a dataset DS of 3 or more points, preferably 5 or more points. However, conventionally, there is a method of calculating SOH using a dataset DS of 2 points (t0, t1) using the following equations (1) and (2).

number

[0020] On the other hand, in this embodiment, the SOH estimation unit 13 estimates SOH using a dataset DS with multiple points (3 or more points, preferably 5 or more points). The error of the SOC estimate relative to the true value is expected to vary randomly between positive and negative values. In this case, using a multi-point dataset DS can reduce the impact on the SOH estimation accuracy because the estimation errors of each point cancel each other out overall.

[0021] Specifically, the SOH estimation unit 13 can estimate SOH with reduced estimation error by calculating a regression line using the least squares method with respect to the integrated current value ΔQ and the estimated SOC value of the dataset DS. The regression line calculated using the least squares method approximates the line shown in Figure 2(c).

[0022] The regression line obtained by simple regression analysis using two variables x (integrated current value ΔQ) and y (estimated SOC value) is expressed by the following equation (3). y = ax + b ··· Equation (3)

[0023] When expressing Equation (3) as a matrix, it becomes the following equations (4) to (7).

Number

[0024] Figure 3 is a diagram showing an example of SOH calculation. As shown in Figure 3, the SOH estimation unit 13 creates the matrix Phi using the estimated SOC value of the data set DS. The SOH estimation unit 13 creates a matrix Phi of n rows and 2 columns (n = number of data sets DS) with the estimated SOC value in the first column and 1 in the second column. The SOH estimation unit 13 also creates Y using the integrated current value ΔQ of the data set DS. The SOH estimation unit 13 calculates a set of coefficients A[a, b] by performing the matrix operation of Equation (8) using the created matrices Phi and Y. The SOH estimation unit 13 obtains the first element of the coefficient A as the slope a of the regression line.

[0025] The slope a of the regression line is expressed by the following equation (9). a = FCC0 × SOH ··· (9) The SOH estimation unit 13 can calculate the estimated SOH value of the battery 5 by dividing the obtained slope a by the initial full charge capacity FCC0.

[0026] The SOH estimation unit 13 temporarily stores the estimated SOH value calculated during the vehicle's travel in the storage unit 14. When the vehicle's travel ends, the SOH estimation unit 13 uses the last estimated SOH value (SOH lastThe result is smoothed and stored in the memory unit 14 as the estimated SOH value at the end of this run. The SOH estimation unit 13 can perform weighted averaging as an example of smoothing processing. The SOH estimation unit 13 uses the SOH estimated value (SOH) stored in the storage unit 14 at the end of the previous run. pre Using ), a weighted average can be performed by the following equation (10). Estimated SOH value at the end of this run = SOH last ×W+SOH pre ×(1-W)...Equation (10) Here, W is the weight and is a positive number less than 1.

[0027] Figure 4 is a flowchart showing the processing flow of the estimation device 1 while the vehicle is in motion. As described above, when the vehicle starts moving, the current sensor 6 and the voltage sensor 7 measure the current and terminal voltage of the battery 5 at a predetermined sampling period. As shown in Figure 4, while the vehicle is in motion, the estimation device 1 receives data from the current sensor 6 and the voltage sensor 7 at each measurement time t n The measured values ​​(current value I, terminal voltage value V) are input (Step S01: Yes). When a measurement value is input, the current integration unit 11 calculates the current integration value ΔQ, and the SOC estimation unit 12 estimates the SOC (step S02). The current integration value ΔQ and the SOC estimate are calculated at measurement time t n The associated dataset DS is stored in the memory unit 14. When the dataset DS stored in the memory unit 14 reaches 3 or 5 points (step S03: Yes), the SOH estimation unit 13 retrieves the dataset DS and starts estimating the SOH (step S04). The SOH estimation unit 13 temporarily stores the estimated SOH values ​​in the memory unit 14. If the vehicle has not yet finished running (step S05: No), the SOH estimation unit 13 returns to step S01 and, when new measured values ​​(current value I, terminal voltage value V) are input, performs the processing in steps S02 to S04. When the vehicle's journey is complete (step S05: Yes), the SOH estimation unit 13 displays the last estimated SOH value. last The data is then smoothed (step S06) and stored in the memory unit 14 as the estimated SOH value at the end of this run.

[0028] As described above, the estimation device 1 according to this embodiment includes, for example, the following configuration. (1) Estimation device 1 estimates the State of Health (SOH) of battery 5. The estimation device 1 comprises a current integration unit 11, a SOC estimation unit 12, and a SOH estimation unit 13 (health estimation unit). The current integrating unit 11 calculates multiple time points t during the charging and discharging of the battery 5. n Using the current value I of battery 5 measured, from the start time t0 to each time point t n Calculate the integrated current value ΔQ up to that point. The SOC estimation unit 12 calculates multiple time points t n Using the current value I and terminal voltage value V of battery 5 measured at each measurement time t n Calculate the estimated SOC value in this case. The SOH estimation unit 13 uses three or more, preferably five or more, data points from a dataset DS that includes the integrated current value ΔQ and the estimated SOC value, and estimates the SOH of the battery 5 based on a regression line calculated by the least squares method. Specifically, the SOH estimation unit 13 can calculate the SOH estimate by dividing the slope a of the regression line calculated using the dataset DS by the initial full charge capacity FCC0 of the battery 5.

[0029] Conventionally, there is a method for calculating the State of Health (SOH) of battery 5 based on the change in State of Charge (SOC) and the integrated current value ΔQ at two points in time (t0, t1). However, since the SOC is an estimated value, estimation errors occur. If only two SOC estimates are used, the estimation error per point can significantly affect the accuracy of the SOH estimation. If the accuracy of the SOH estimation is not good, it may be necessary to install a larger battery 5 to provide a large safety margin in the charge / discharge control range of battery 5. This can affect the installation cost of battery 5 and the layout of the in-vehicle equipment, including battery 5.

[0030] In this embodiment, the SOH estimation unit 13 estimates SOH by regression analysis using the least squares method with a dataset DS (current integrated value ΔQ and SOC estimate) of 3 or more points (preferably 5 or more points). As shown in Figure 2(b), the error in the SOC estimate relative to the true value is expected to change randomly between positive and negative, and therefore, at numerous measurement points t n By using the dataset DS, the estimation errors for SOC at each point are offset. This allows estimation device 1 to reduce the impact of SOC estimation errors and improve the estimation accuracy of SOH.

[0031] (4) Battery 5 supplies power for driving the vehicle. The SOH estimation unit 13 starts estimating SOH when it acquires at least three, preferably five, data sets DS after the vehicle has started moving, and thereafter performs SOH estimation each time a new data set DS is acquired.

[0032] As described above, in this embodiment, the estimation accuracy of SOH is improved by using a dataset DS with multiple points. Therefore, the SOH estimation unit 13 can ensure the estimation accuracy of SOH by acquiring a dataset DS with at least 3 points, preferably 5 points. Furthermore, the estimation device 1 of this embodiment improves the accuracy of SOH estimation by using a dataset of multiple points. Therefore, as time elapses from the start of vehicle operation, a larger dataset becomes available, enabling highly accurate SOH estimation.

[0033] (5) The estimation device 1 includes a storage unit 14 that stores the SOH estimate value each time the vehicle runs on the battery 5. The SOH estimation unit 13, at the end of the vehicle's journey, calculates the last estimated SOH value (SOH last ) is used to store the estimated SOH value (SOH) stored in the memory unit 14 during the previous run. pre The smoothed value is stored in the storage unit 14.

[0034] By storing the smoothed SOH estimate in the storage unit 14, the rationality of the SOH statistical data can be improved. Also, when the vehicle runs again, the SOH estimate at the end of the previous run (SOH pre This can be used for charging and discharging control of battery 5 and for controlling the operation of the vehicle.

[0035] [Example 1] Figure 5 is a block diagram showing the configuration of the estimation device 1A according to modified example 1. As shown in Figure 5, the estimation device 1A according to the modified example 1 includes a timing unit 15 in addition to the functional configuration described in the embodiment. The timing unit 15 starts measuring from the measurement start time t0 of the current sensor 6 and voltage sensor 7 to each measurement time t n The elapsed time T up to the specified time is measured. The timing unit 15 measures the measured elapsed time T at each measurement point t. n It is linked to and stored in the memory unit 14. In other words, in modified example 1, the measurement time t n A dataset DS is stored, consisting of the current integration value ΔQ, the SOC estimate, and the elapsed time T associated with the data. The SOH estimation unit 13 uses this dataset DS, which consists of these three elements, to estimate the SOH. The SOH estimation unit 13 can perform estimation using a dataset DS of three or more points, preferably five or more points, similar to the embodiment.

[0036] In Modification 1, the measurement error I occurs in the current sensor 6 of the battery 5. err To take this into account, we add the elapsed time T to the SOH estimation. As shown in Figure 5, the current value I measured by the current sensor 6 is equal to the true value of the current flowing through the battery 5 with a measurement error I. err It can be considered as something that has been added. The integrated current value ΔQ is the sum of the current values ​​I measured by the current sensor 6. Therefore, as shown in equation (12) below, from the start of measurement t0 to the measurement time t n The larger the elapsed time T, the greater the measurement error I relative to the integrated current value ΔQ. err The effect (I err ×T) becomes large. And, as shown in equation (11) below, the measurement error I err This also affects the estimation accuracy of SOH.

number

[0037] Therefore, by adding the elapsed time T to the SOH estimation, the measurement error I relative to the integrated current value ΔQ can be reduced. err This can reduce the impact of [unspecified factor] and improve the accuracy of SOH estimation. Specifically, the SOH estimation unit 13 performs a multiple regression analysis using a regression model where the estimated SOC value, elapsed time T, and integrated current value ΔQ are variables x1, x2, and y, respectively. The multiple regression model is represented by the following equation (13).

number

[0038] The SOH estimation unit 13, similar to the embodiment, performs matrix operations using the dataset DS to obtain coefficient 1, coefficient 2, and intercept in the above equation (13). Coefficient 1 corresponds to the slope of the regression line. The SOH estimation unit 13 can calculate the estimated SOH value by dividing coefficient 1 by the initial full charge capacity FCC0 of the battery 5.

[0039] Figure 6 shows an example of SOH calculation related to Modified Example 1. Figure 6 shows the dataset DS from Figure 3 with the addition of elapsed time T. As shown in Figure 6, in the modified example 1, the SOH estimation unit 13 creates a matrix Phi using the estimated SOC value and elapsed time T of the dataset DS. The SOH estimation unit 13 creates an n x 3 matrix Phi (n = number of datasets DS) with the estimated SOC value in the first column, the elapsed time T in the second column, and 1 in the third column. The SOH estimation unit 13 also creates Y using the integrated current value ΔQ of the dataset DS. The SOH estimation unit 13, similar to the embodiment, can calculate coefficients 1, 2, and the intercept in equation (13) by performing the matrix operation in equation (8) using the created matrices Phi and Y.

[0040] As described above, the estimation device 1A according to modified example 1 has, for example, the following configuration. (2) The estimation device 1A starts from the measurement start time t0 and measures each time point t n It includes a timing unit 15 that measures the elapsed time T up to that point. The SOH estimation unit 13 uses three or more time points t n Using a dataset DS consisting of the integrated current value ΔQ, estimated SOC value, and elapsed time T, SOH is estimated based on a regression line calculated using the least squares method.

[0041] The integrated current value ΔQ is calculated from the measurement value (current value I) of the current sensor 6 installed on the battery 5, therefore the measurement error I of the current sensor 6 is considered. err This affects the estimation accuracy of SOH. Measurement error I err The effect of the current integration value ΔQ on the measurement start time t0 to the measurement time t n Since there is a correlation with the elapsed time T up to that point, by adding the elapsed time T to the SOH estimation, the measurement error I can be calculated. err This reduces the impact of [the relevant factor] and improves the estimation accuracy of SOH.

[0042] [Differentiation 2] Figure 7 is a block diagram showing the configuration of the estimation device 1B according to modified example 2. As described in the embodiment, the SOC estimation unit 12 (overvoltage estimation unit) estimates the overvoltage η of the battery 5 in the process of estimating the SOC. As shown in Figure 7, in the modified example 2, the SOC estimation unit 12 estimates the overvoltage η at measurement time t n The data is linked to and stored in the memory unit 14. The overvoltage η is stored in the memory unit 14 as information related to the dataset DS, which consists of elements for estimating SOH.

[0043] The SOH estimation unit 13, similar to the embodiment, obtains the dataset DS stored in the storage unit 14 and estimates the SOH, but in the modified example 2, the measurement time t when the overvoltage η exceeds the threshold TH is n The dataset DS will be excluded from the estimation. The SOC estimation unit 12 estimates the SOC value by estimating the overvoltage η, but if the absolute value of the overvoltage η is large, estimation errors in the overvoltage η are likely to occur. As a result, estimation errors in the SOC are also likely to occur. Therefore, it is possible to determine whether the dataset DS is suitable for use in SOH estimation based on the magnitude of the overvoltage η of the battery 5.

[0044] The SOH estimation unit 13 calculates each measurement time t n Before performing SOH estimation using the dataset DS, the overvoltage η is compared with the threshold TH. The threshold TH is a reference value for determining the magnitude of the overvoltage η and can be set as appropriate in tests or simulations. The SOH estimation unit 13 determines a certain measurement time t n If the overvoltage η exceeds the threshold TH, then the measurement time t n The dataset DS is excluded from the estimation target. This allows the SOH estimation unit 13 to perform SOH estimation while excluding data that would cause a decrease in the accuracy of SOH estimation.

[0045] Specifically, the SOH estimation unit 13 determines the measurement time t when the overvoltage η exceeds the threshold TH. nSOH is not estimated at this point. Furthermore, in subsequent SOH estimations, the measurement point t where the overpotential η exceeds the threshold TH is also not estimated. n The dataset DS (SOC estimate and current integration value ΔQ) is excluded from the estimation. The SOH estimation unit 13 may delete the dataset DS that has been excluded from the estimation target from the storage unit 14, or it may assign a flag to the dataset DS indicating that it has been excluded from the estimation target.

[0046] Figure 8 is a flowchart showing the processing flow of the estimation device 1B according to modified example 2. As shown in Figure 8, while the vehicle is in motion, the estimation device 1B receives data from the current sensor 6 and the voltage sensor 7 at each measurement point. n The measured values ​​(current value I, terminal voltage value V) are input (Step S11: Yes). When a measurement value is input, the current integration unit 11 calculates the current integration value ΔQ, the SOC estimation unit 12 estimates the overvoltage η, and estimates the SOC using the overvoltage η (step S12). The current integration value ΔQ and the estimated SOC value are calculated at measurement time t n The associated dataset DS is stored in the storage unit 14. The overvoltage η is measured at time t n The information linked to the dataset DS is stored in the memory unit 14. The SOH estimation unit 13 compares the overvoltage η with the threshold TH (step S13). If the overvoltage η exceeds the threshold TH (step S13: Yes), the SOH estimation unit 13 determines the measurement time t n The dataset DS is excluded from the estimation (step S14), and the process returns to step S11. If the overvoltage η is less than or equal to the threshold TH (step S13: No), the SOH estimation unit 13 proceeds to step S15. Similar to the embodiment, when the dataset DS that has not been excluded from the estimation target reaches 3 or 5 points (step S15), the SOH estimation unit 13 performs SOH estimation (step S16). The processes in steps S17 to S18 are the same as steps S05 to S06 in the embodiment (see Figure 4), so their explanation is omitted.

[0047] As described above, the estimation device 1B according to modified example 2 has, for example, the following configuration. (4) Battery 5 supplies power for driving the vehicle. The estimation device 1B measures each measurement time t during the charging and discharging of battery 5. n The system includes a State of Charge (SOC) estimation unit 12 (overvoltage estimation unit) that estimates the overvoltage η of the battery 5 using the terminal voltage value V of the battery 5 measured by [device name]. The SOH estimation unit 13 determines the measurement point t when the overvoltage η exceeds the threshold TH. n Excluding the DS dataset, we perform the estimation of SOH.

[0048] When the overvoltage η of battery 5 is high, it becomes difficult to perform accurate SOH estimation. In Modification 2, the SOC estimation unit 12 estimates each measurement time t during SOC estimation. n The overvoltage η is stored in the memory unit 14. The SOH estimation unit 13 compares the overvoltage η with the threshold TH, and if it exceeds the threshold TH, it checks the measurement time t n The dataset DS is excluded from the estimation of SOH. The SOH estimation unit 13 can maintain the accuracy of SOH estimation by excluding data that would cause a decrease in the accuracy of SOH estimation.

[0049] The configuration in which the SOH estimation unit 13 of Modification 2 compares the overvoltage η with the threshold TH may also be applied to Modification 1 (see Figure 5). Furthermore, while the embodiments and modifications described an example in which the SOH estimation unit 13 performs SOH estimation using the data set DS of the entire period from the measurement start time t0 of the current sensor 6 and voltage sensor 7 while the vehicle is in motion, the invention is not limited to this example. For example, the SOH estimation unit 13 may divide the elapsed time from the measurement start time t0 into fixed time intervals and estimate SOH based on the data set DS acquired at fixed time intervals. When the sampling period of the current sensor 6 and voltage sensor 7 is short, or when the vehicle's running time is long, the number of points in the dataset DS may increase. However, the SOH estimation unit 13 can reduce the computational load in such cases by performing SOH estimation in fixed time intervals. In addition, since the dataset DS for which SOH estimation has been completed can be deleted from the storage unit 14, the load on the data capacity of the storage unit 14 can also be reduced. [Explanation of Symbols]

[0050] 1, 1A, 1B Estimator 5 batteries 6 Current Sensor 7. Voltage Sensor 11 Current Integration Unit 12. SOC Estimation Unit (Overvoltage Estimation Unit) 13 SOH estimation section (healthiness estimation section) 14 Storage section 15 Timing section

Claims

1. An estimation device for estimating the health of a battery, A current integration unit calculates the total current value from the start of measurement to each measurement point using the current values ​​of the battery measured at multiple points during the charging and discharging of the battery. An SOC estimation unit calculates an SOC estimate value at each of the measurement points using the current value and terminal voltage value of the battery measured at the aforementioned multiple time points. An estimation device comprising: a health estimation unit that estimates the health level based on a regression line calculated by the least squares method using three or more data points, including the current integrated value and the SOC estimated value at each of the aforementioned measurement points.

2. In claim 1, The system includes a timing unit that measures the elapsed time from the start of measurement to each of the measurement points. The health estimation unit is an estimation device that estimates the health based on a regression line calculated by the least squares method using a dataset including the integrated current value, the SOC estimate value, and the elapsed time at each measurement point.

3. In claim 1 or 2, The aforementioned battery supplies power for driving the vehicle. During the charging and discharging of the battery, the system includes an overvoltage estimation unit that estimates the overvoltage of the battery using the current value and terminal voltage value of the battery measured at each measurement point. The health estimation unit is an estimation device that estimates the health by excluding the data set at the measurement point when the overvoltage exceeded a threshold.

4. In claim 1 or 2, The aforementioned battery supplies power for driving the vehicle. The health estimation unit is an estimation device that starts estimating the health status when at least three data points have been acquired after the vehicle has started moving, and thereafter performs the health status estimation each time a new data set is acquired.

5. In claim 4, The battery is equipped with a storage unit that stores an estimated value of its health status each time the vehicle runs. The health estimation unit is an estimation device that, at the end of the vehicle's run, smooths the last estimated health value using the health value stored in the storage unit during the previous run, and stores it in the storage unit.

Images