JP6548387B2 - Method and apparatus for estimating state of charge of secondary battery - Google Patents

Description

  The present invention relates to a method and apparatus for estimating the state of charge of a secondary battery.

  Heretofore, various chargeable and dischargeable secondary batteries used mainly as a power source for portable devices have been proposed. Furthermore, in recent years, in consideration of the environment, large-sized devices equipped with secondary batteries have been developed. For example, a vehicle equipped with a secondary battery stores regenerative electric power generated at the time of braking in the secondary battery and uses it as a power source of the vehicle. In addition, the railway substation connected to the overhead wire on which the secondary battery system is installed absorbs the regenerative power generated by the train, and supplements the running power consumed by the train.

  In these applications, the remaining capacity of the secondary battery, that is, the state of charge (SOC: state of charge) of the secondary battery is highly accurate in order to prevent the secondary battery from becoming unusable due to overdischarge or overcharge. It is necessary to have a technique to estimate Conventionally, as a method of estimating the SOC of a secondary battery, a method of estimating based on a current integrated value obtained by integrating charge and discharge current values, and a method of estimating based on the correlation between a battery open circuit voltage and an SOC are known. (See, for example, Patent Documents 1 and 2).

JP, 2005-269824, A JP 2007-292778 A

  However, in the estimation method based on the current integrated value, there is a problem that the detection error of the current value is accumulated when the operation is performed for a long time, and the estimation accuracy of the SOC gradually decreases.

  Further, in the method of estimation based on the correlation between the battery open-circuit voltage and the SOC, the relationship between the open-circuit voltage value and the SOC changes by repeating charging and discharging, so that the estimation accuracy of the SOC is lowered. is there.

  An object of the present invention is to provide a secondary battery charge state estimation method and estimation device with high estimation accuracy in order to solve the above-mentioned problems.

  In order to achieve the above object, a method of estimating a state of charge of a secondary battery according to the present invention is a method of estimating a state of charge of a secondary battery based on an open circuit voltage value and a current integration value. The instantaneous charge state map for determining the relationship between the instantaneous open circuit voltage value and the charge state estimated value at the time of charge state estimation is updated based on charge / discharge characteristic data after the start of use of the secondary battery, and the update Based on the instantaneous charge state map, the instantaneous charge state estimated value at the time of charge state estimation is calculated, and the charge state estimated value is calculated based on the integrated value of the current flowing through the secondary battery, and the instantaneous A control charge state estimate value used for control of the secondary battery is calculated based on a typical charge state estimate value and a charge state estimate value based on the current integrated value.

  According to this configuration, the state of charge of the secondary battery is calculated based on both the open circuit voltage value and the current integrated value, so using the open circuit voltage value in the case of using a current integrated value that degrades accuracy in the long run The estimation accuracy of the state of charge of the secondary battery is improved by complementing the calculation. Moreover, the relationship between the open circuit voltage value and the estimated charge condition value changes as the charge and discharge are repeated, and based on the charge and discharge history, the instantaneous charge condition map that determines the relationship between the open circuit voltage value and the estimated charge condition value. Since updating is performed, it is possible to estimate the state of charge with higher accuracy.

  In the method of estimating the state of charge of a secondary battery according to an embodiment of the present invention, complete charge characteristic data, which is charge characteristic data when charged from 0% to 100%, and discharge from 100% to 0% of charge. The partial charge / discharge characteristic data which is the partial charge / discharge data between 0% and 100% of the charge state is normalized based on the complete discharge characteristic data which is the discharge characteristic data in the case of It is preferable to update the instantaneous charge state map using the partial charge / discharge voltage standard value. According to this configuration, the instantaneous charge state map is updated based not only on the full charge and discharge characteristics but also on the relative relationship between the full charge and discharge characteristics and the partial charge and discharge characteristics, so the charge state is estimated with extremely high accuracy. be able to.

  In the method of estimating the state of charge of a secondary battery according to an embodiment of the present invention, when switching from charge to discharge, if either the duration of charge in the last charge or the charge current integration amount exceeds a predetermined value. Preferably, the instantaneous charge state map is updated, and when switching from discharge to charge, the instantaneous charge state map is updated if any of the discharge last time and the discharge current integrated amount exceeds a predetermined value. . According to this configuration, the instantaneous charge state map can be updated at an appropriate timing according to the type and application of the secondary battery, the charge and discharge pattern, and the like.

  In the method for estimating the state of charge of a secondary battery according to one embodiment of the present invention, first-order delay processing using a time constant is performed on a charge / discharge current value to calculate a current first-order delay value, and based on this current first-order delay value. Preferably, the duration of the charge and the duration of the discharge are determined. According to this configuration, it is possible to more appropriately determine the timing at which the instantaneous charge state map is updated in an application in which charge and discharge are switched in a particularly short cycle.

  In the method of estimating the state of charge of a secondary battery according to one embodiment of the present invention, a time constant is set according to a region of the state of charge, and the instantaneous charge state estimated value and the current integration are calculated using this time constant. It is preferable to calculate a control charge state estimated value used to control the secondary battery based on a value-based charge state estimated value. Depending on the type of secondary battery, the amount of change in the open circuit voltage value with respect to the change in the state of charge may greatly differ depending on the region of the state of charge. According to the above configuration, the contribution ratio of the estimated value based on the open circuit voltage and the contribution ratio of the estimated value based on the current integration value are appropriately adjusted to such a secondary battery according to the region of the state of charge. Can estimate the state of charge with higher accuracy.

  In the method of estimating the state of charge of a secondary battery according to an embodiment of the present invention, the setting of the time constant is performed for a plurality of predetermined state of charge regions between 0% and 100% in the instantaneous charge state map. Calculating the voltage change rate with respect to the charge state change, and calculating and setting the time constant in each of the charge state regions from the voltage change rate and a predetermined decreasing function of the voltage change rate with respect to the charge state change. Is preferred. According to the above configuration, setting of the time constant according to the region of the state of charge of the secondary battery can be performed simply and appropriately from the instantaneous charge state map.

  In the method of estimating charge state of a secondary battery according to an embodiment of the present invention, it is preferable to correct the time constant in accordance with the charge / discharge pause time. More specifically, for example, it is preferable to correct the time constant so that the time constant has a positive correlation with the length of the charging / discharging pause time. Although the open circuit voltage of the battery changes depending on the rest time after charge and discharge stop, according to the above configuration, it is possible to estimate with higher accuracy taking into consideration the influence of the rest time between charge and discharge.

  In the method of estimating charge state of a secondary battery according to one embodiment of the present invention, it is preferable to correct the time constant in accordance with the magnitude of charge and discharge current. More specifically, for example, it is preferable to correct the time constant so that the time constant and the magnitude of the charge and discharge current have a positive correlation. According to the above configuration, it is possible to suppress an increase in the error of the SOC estimated value calculated based on the open circuit voltage.

  In the method of estimating charge state of a secondary battery according to one embodiment of the present invention, further, an internal resistance reference value used to calculate the instantaneous open circuit voltage value is based on charge / discharge characteristic data of the secondary battery. It is preferable to update the According to this configuration, since the internal resistance value of the secondary battery, which changes due to long-term operation or repetition of charge and discharge, is updated based on the charge and discharge history, the state of charge can be estimated with higher accuracy.

  As described above, according to the method of estimating charging state of a secondary battery and the estimating device according to the present invention, it is possible to estimate the charging state of the secondary battery with high accuracy.

It is a block diagram which shows schematic structure of the charge condition estimation apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the outline of the charge condition estimation method which concerns on one Embodiment of this invention. It is a figure which shows the example of internal resistance value calculation in the charge condition estimation method which concerns on one Embodiment of this invention. It is a flowchart which shows the example of the update of the instantaneous charge condition map in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of the reference | standard charge / discharge map used for the update of the instantaneous charge condition map in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of normalization of the voltage value in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of the partial charge map created in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of the partial discharge map created in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of the update of the instantaneous charge condition map in the charge condition estimation method which concerns on one Embodiment of this invention. It is a table | surface which shows the example of the charge efficiency map used in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the setting example of the control SOC calculation time constant in the charge condition estimation method which concerns on one Embodiment of this invention. It is an example of the graph used for calculation of the time constant in the charge condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of the relationship between the open circuit voltage value at the time of changing charge current value, and a charge condition estimated value. It is a graph which shows the example of the relationship between the open circuit voltage value at the time of changing a discharge current value, and a charge condition estimated value.

  Hereinafter, although an embodiment concerning the present invention is described according to a drawing, the present invention is not limited to this embodiment.

  FIG. 1 shows a schematic configuration of a charge state estimation device 1 that executes a method of estimating a charge state of a secondary battery according to an embodiment of the present invention. The charge state estimation device 1 is a device that estimates the charge state (SOC: State of Charge) of the secondary battery based on the open circuit voltage value and the current integrated value, and calculates the instantaneous open circuit voltage value at the time of charge state estimation. Instantaneous charge state map update block 3 which updates the instantaneous charge state map which determines the relationship with the charge state estimated value based on charge / discharge characteristic data after the start of use of the secondary battery, based on the updated instantaneous charge state map The momentary charge state estimation block 5 which calculates momentary charge state estimated value at the time of charge state estimation, the charge state estimate value is calculated based on the integrated value (current integrated value) of the current value flowing through the secondary battery Control charge state estimation for control of a secondary battery based on the current integration charge state estimation block 7 and the charge state estimation value based on the instantaneous charge state estimation value and the current integration value A control charge state estimation block 9 for calculating a value is provided. Further, the charge state estimation device 1 is provided with a storage device (for example, a memory) (not shown) used for storing the current integrated value, etc., and a clocking means (for example, clock) (not shown) used for calculating the current integrated value. ing.

  The calculation flow of the charge condition estimation method which concerns on FIG. 2 at this embodiment is shown. The calculation flow is a first step of measuring a battery voltage value, a battery current value, and a battery temperature, and an instantaneous charge state estimated value from the battery voltage value, the battery current value, and the battery temperature value (hereinafter referred to as "instant SOC estimated value" And the third step of obtaining the estimated state of charge (hereinafter referred to as “the current integrated SOC estimated value”) based on the current integrated value, and the instantaneous SOC estimated value and the current integrated SOC estimation. And a fourth step of determining and outputting a control charge state estimated value (hereinafter, referred to as “control SOC estimated value”) to be used for charge / discharge control of the secondary battery based on the value.

  In the first stage, the battery voltage value, battery current value and battery temperature of the secondary battery are measured (step S1). These actual measurement data are acquired by the voltage measuring device 11, the current measuring device 13 and the battery temperature measuring device 15, respectively, and stored in a storage device (not shown). Further, the time when the present calculation flow is started is measured by a clocking means (not shown), and this time is stored in a storage device (not shown).

  When a battery module or a battery system is configured by combining a plurality of secondary batteries (cells) in series and in parallel, the measured voltage value of the battery module or battery system in consideration of the configuration of the battery module or the battery system, The current value and the battery temperature may be converted into a battery voltage value in a cell unit, a battery current value, and a battery temperature, and these may be stored in a storage device (not shown). For example, in the case of a battery module formed by connecting a predetermined number of secondary batteries in series, an existing conversion method can be used, such as using a value obtained by dividing the voltage value of the battery module by the predetermined number as the battery voltage value. The same applies to the battery current value and the battery temperature, so the details will be omitted.

In the second step, an instantaneous SOC estimated value is obtained from an instantaneous charge state map that defines the relationship between the open circuit voltage value and the estimated charge state value prepared in advance and the calculated open circuit voltage value. The open circuit voltage value is calculated by the following equation (1). Hereinafter, the sign of the measured current is defined as positive at the time of discharge and negative at the time of charge.
Open circuit voltage (V) = Measured voltage (V) + (Internal resistance (Ω) x Measured current (A)) (1)

  Here, before the first step, that is, before starting the monitoring of the SOC of the secondary battery, create an internal resistance characteristic map that associates the battery temperature, the SOC, and the internal resistance value of the secondary battery according to the following procedure, Store in a storage device not shown.

  First, at a predetermined battery temperature and a predetermined SOC, charge and discharge of the secondary battery are performed at various charge / discharge current values for a predetermined time, and a battery voltage value in the middle is measured. For example, in a secondary battery with a rated capacity of 141 Ah, after setting the battery temperature to 10 ° C. and the SOC to 10%, discharge for 70.5 A (0.5 C) is performed for 15 seconds, and the battery voltage 10 seconds after the discharge start taking measurement. Next, charging for 70.5 A (0.5 C) is performed for 15 seconds, and a battery voltage value 10 seconds after the start of charging is measured. Furthermore, discharge of 141A (1.0C) for 15 seconds, charge of 141A (1.0C) for 15 seconds, discharge of 282A (2.0C) for 15 seconds, charge of 282A (2.0C) for 15 seconds, and each charge / discharge Measure the battery voltage value 10 seconds after the start. Second, the internal resistance value of the secondary battery is determined from the measured charge / discharge current value and the battery voltage value. In the above example, three constant current discharges and three constant current charges were performed with different current values, and battery voltage values corresponding to the respective current values were measured, as shown in FIG. 3 (a). , Plot the battery current value and the battery voltage value. Then, from the battery current value and the battery voltage value plotted in the graph shown in FIG. 3A, the slope of the change of the voltage value with respect to the change of the current value is determined by linear approximation, and this slope is the internal resistance value of the secondary battery Do.

  Third, the first and second procedures are repeated while changing the battery temperature and the SOC to create an internal resistance characteristic map. In the above-mentioned example, in the internal resistance characteristic map shown in FIG. 3B, the internal resistance value r11 is obtained when the battery temperature is 10 ° C. and the SOC is 10%. Similarly, the first and second procedures are repeated by appropriately changing the battery temperature and the SOC, and the internal resistance characteristic map shown in FIG. 3B is completed.

  The method of calculating the internal resistance value of the secondary battery is not limited to the method described above. For example, the internal resistance value at the time of discharge is divided into positive (discharge) and negative (charge) current values. -The internal resistance value during charging may be calculated separately. Further, the approximation method is not limited to linear approximation, and various methods can be adopted.

  Next, based on the battery temperature measured in step S1 and the control SOC estimated value (described later) obtained one calculation flow before, the internal resistance value calculation block 17 obtains the internal resistance value from the internal resistance characteristic map (step S2) . If the internal resistance value is not found in the internal resistance characteristic map, the internal resistance value calculation block 17 obtains the internal resistance value by linear interpolation. For example, in the internal resistance characteristic map of FIG. 3B, when the internal resistance having a battery temperature of 13 ° C. and a control SOC value of 10% is obtained, the internal resistance value calculation block 17 has a battery temperature of 10 ° C. and SOC 10%. The internal resistance value is calculated by linear interpolation from the internal resistance value and the internal resistance value at a battery temperature of 15 ° C. and SOC 10%. Note that methods other than linear interpolation may be used.

  When this calculation flow is the first time, there is no control SOC estimated value since it does not exist one calculation flow before. In this case, an SOC value obtained by another method may be used instead of the control SOC estimated value. For example, a known method may be used, such as using the SOC value based on the current integration value of Patent Document 1.

Generally, the internal resistance value of the secondary battery is deteriorated (increased) by repeating charge and discharge. In addition, since there are manufacturing variations in secondary batteries, there are also variations in internal resistance values. Therefore, by continuously updating the internal resistance characteristic map at predetermined time intervals based on the following equation (2), it is possible to obtain an internal resistance value that regularly reflects the deterioration or variation of the secondary battery. It is preferable to do.
Internal resistance (Ω) = (Open voltage (V)-Measured voltage (V)) / Measured current (A) (2)

  In the present embodiment, the battery voltage value, the battery current value, and the battery temperature measured before one calculation flow, and the open circuit voltage value before the one calculation flow calculated in step S3 (described later) based on these values are internally The resistance reference value calculation block 19 calculates the internal resistance value using equation (2). Further, the internal resistance reference value calculation block 19 calculates the battery temperature and the SOC based on the battery temperature measured before one calculation flow, the control SOC estimated value obtained before one calculation flow, and the calculated internal resistance value. The internal resistance characteristic map shown in FIG. 3B, which associates the control SOC value) with the internal resistance value of the secondary battery, is updated (step S2 '). The internal resistance characteristic map may not be updated regularly or continuously, and may be updated at any timing, but in order to estimate the state of charge of the secondary battery with high accuracy, the frequency of update is higher Preferably, it is preferable to periodically and continuously renew.

  Next, the open circuit voltage calculation block 21 obtains the open circuit voltage value from the battery voltage value and the battery current value actually measured in step S1, and the internal resistance value obtained in step S2 based on the equation (1) Step S3), store in a storage device not shown.

  In this embodiment, the instantaneous charge state map update block 3 stores the instantaneous charge state map which is stored in the storage device (not shown) and determines the relationship between the instantaneous open circuit voltage value at the time of charge state estimation and the charge state estimated value. It updates based on the charge / discharge characteristic data after the start of use of a secondary battery (step S4). The update of the instantaneous charge state map will be described in detail below. Note that in the following description, in order to facilitate understanding, expressions such as “use a graph” and “create a graph” may be used in some cases, but “graph” here is an object. It refers to data that indicates the correlation between two parameters, and does not have to be a visually represented graph. For example, a "graph" may show the correlation between two parameters in the form of a table.

  Before the first stage, that is, before starting the monitoring of the SOC of the secondary battery, as shown in FIG. 5, a reference map to be used as a reference in updating the instantaneous charge state map is created and stored in a storage device not shown. Store. Specifically, full charge from 0% to 100% charge state, and partial charge test from multiple different charge states to 100% (30%, 40%, 50%, 60 charge states in FIG. 5A) Five partial charge tests (%, 70% to 100%) are performed to create a reference charge map consisting of graphs (charge characteristic data) showing changes in open circuit voltage values with respect to various charge states. Similarly, full discharge from 100% to 0% of charge state, and partial discharge test from 0% of different charge states (30%, 40%, 50%, 60% state of charge in FIG. 5 (b) Five partial discharge tests (from 70% to 0%) are performed to create a reference discharge map consisting of graphs (discharge characteristic data) showing changes in open circuit voltage values with respect to various charge states. In the present embodiment, a test is performed at a charge / discharge current of 0.2 C to create a reference charge map and a reference discharge map. The reference charge map and the reference discharge map are not limited to 0.2 C, but may be created by conducting tests at desired charge / discharge current values in consideration of embodiments such as 0.1 C and 0.01 C. Can.

  Even if the same open circuit voltage value is indicated, the state of charge differs depending on whether the secondary battery is charging or discharging. For example, according to the reference charge map of FIG. 5A, when the open circuit voltage indicates 1.361 V, if partial charging is being performed from instantaneous SOC 50%, partial charge from instantaneous SOC 50% to 100%. Referring to the graph according to, it can be seen that the instantaneous SOC is 60%. On the other hand, according to the reference discharge map of FIG. 5B, when performing partial discharge from instantaneous SOC 70%, referring to the graph related to partial discharge from instantaneous SOC 70% to 0%, the instantaneous SOC is 65%. I understand that there is. As described above, it is possible to appropriately determine the instantaneous SOC by determining whether the secondary battery is charging or discharging based on the measured current and appropriately selecting the charge map or the discharge map.

  Furthermore, the charging state determined based on the reference charging map and the reference discharging map by repeating charging and discharging of the secondary battery, in particular, repeating charging and discharging when the state of charge is greater than 0% and less than 100%; Deviation from the actual state of charge occurs, and the accuracy of estimation of the state of charge deteriorates. Therefore, in step S4, the instantaneous charge state map update block 3 is from 100% to 0% full charge characteristic data, which is charge characteristic data when the secondary battery is charged from 0% to 100% charge state. Standardize the partial charge / discharge characteristic data which is the partial charge / discharge data between 0% and 100% of the charge state based on the complete discharge characteristic data which is the discharge characteristic data when discharging the secondary battery, The instantaneous charge state map is updated using the partial charge / discharge voltage standard value obtained by this normalization. FIG. 4 shows a flow of creation and update of the instantaneous charge state map.

First, based on the reference charge map, the voltage value corresponding to each SOC value in each partial charge is normalized by the voltage value in complete charge and the voltage value in complete discharge. Similarly, based on the reference discharge map, the voltage value corresponding to each SOC value in each partial discharge is normalized by the voltage value in full charge and the voltage value in full discharge. The standard value of the partial charge voltage value is calculated by the following equation (3), and the standard value of the partial discharge voltage value is calculated by the following equation (4).
Partial charge voltage standard value = (partial charge voltage value-complete discharge voltage value)
/ (Complete charge voltage value-complete discharge voltage value) (3)
Partial discharge voltage standard value = (partial discharge voltage value-complete discharge voltage value)
/ (Complete charge voltage value-complete discharge voltage value) (4)

  The example which normalizes the voltage value in SOC = 60% in the partial charge from SOC50% is shown. For example, referring to FIG. 5 (a), the voltage value at SOC = 60% in full charge is 1.390 V, and referring to FIG. 5 (b), the voltage value at SOC = 60% in full discharge is 1. Referring to the graph relating to partial charge from SOC 50% to 100% in FIG. 5A, the voltage value at SOC = 60% in partial charge from 50% of SOC is 1.361 V, and therefore the partial charge standard is used. From the above equation (3), the value is (1.361-1.315) / (1.390-1.315) = 0.613.

Next, when the operation of the secondary battery is switched from charge to discharge, the partial charge map is created / updated based on the following equation (5) using the normalized voltage value.
Partial charge voltage value = Partial charge voltage standard value
× (full charge voltage value-partial discharge voltage value)
+ Partial discharge voltage value (5)

  As mentioned above, the example which normalizes the voltage value in SOC = 60% in the partial charge from SOC50% based on Formula (3) was shown. By repeating the same procedure, based on the reference charge map of FIG. 5A, the reference discharge map of FIG. 5B, and the equation (3), SOC = 50 to 100 in partial charge from SOC 50%. % Partial charge standard value, and then, based on the reference charge map of FIG. 5 (a), the reference discharge map of FIG. 5 (b), and the equation (5), SOC = 50 in partial charge from SOC 50% The partial charge voltage value of 50 to 100% is obtained as shown in the graph of FIG.

  However, for the SOC region exceeding the SOC (discharge switching SOC) at the time of switching from partial charge to partial discharge (partial discharge start point), the voltage value in full charge or partial charge of the reference charge map may be used.

  An example in which partial charging is performed from SOC 0% to 50% and then partial discharging to SOC 30% will be described below. In this example, a graph at the full charge of the reference charge map of FIG. 5 (a) and a graph from SOC 50% to 0% of the reference discharge map of FIG. 5 (b) are used.

  First, a partial charge voltage standard value is obtained in the range of SOC 30% to 50% from these two graphs and the equation (3). Next, in the SOC 30% to 50% range, from the graph (full charge voltage value) in the full charge of the reference charge map and the graph from the SOC 50% to 0% of the reference discharge map (partial discharge voltage value) Based on the equation (5) and the partial charge voltage standard value, a normalized graph is drawn on the partial charge map, and in the SOC 50% to 100% range, the SOC 50% of the graph at the full charge of the reference charge map Use the 100% graph and draw on the partial charge map. The graph shown in FIG. 7 is obtained by the above-described procedure of obtaining a partial charge voltage standard value and drawing a normalized graph based on the standard value when partial discharge is performed from SOC 50% to 30%. It is a graph drawn on a partial charge map.

  In addition, as a result of repeating charging / discharging, when performing partial charge to SOC50% and performing partial discharge to SOC30% after that, it is not the graph from SOC50% to 0% of the reference discharge map of FIG. It is preferable to use a graph from SOC 50% to 0% of the partial discharge map drawn / updated in the following procedure. This is because the partial discharge map is drawn / updated based on the charge / discharge history of the secondary battery, unlike the reference discharge map showing the initial state of the secondary battery, thus reflecting the current state of the secondary battery more It is because it has become a thing. In this embodiment, the partial charge map is updated using the graph in the full charge of the reference charge map of FIG. 5A and the graph from SOC 50% to 0% of the drawn / updated partial discharge map of FIG. (Redraw) As described above, by updating the partial charge map, even when partial charge and discharge are repeated many times, it is possible to obtain an accurate instantaneous SOC estimation value from the open circuit voltage value during charging.

Similarly, when the discharge is switched to the charge, the partial discharge map is created / updated based on the following equation (6) using the normalized voltage value.
Partial discharge voltage value = Partial discharge voltage standard value
× (partial charge voltage value-complete discharge voltage value)
+ Complete discharge voltage value (6)

  However, for the SOC region lower than the SOC (charge switching SOC) at the time of switching from partial discharge to partial charge (partial charge start point), a voltage value in complete discharge or partial discharge of the reference discharge map may be used.

  An example is shown in which after partial charge to SOC 30% after partial charge to SOC 100% after SOC 0% to SOC 100%, partial charge to SOC 70% is performed. In this example, a graph of the complete discharge of the reference discharge map of FIG. 5B and a graph of SOC 30% to 100% of the reference charge map of FIG. 5A are used.

  First, a partial discharge voltage standard value is determined in the range of SOC 30% to 70% from these two graphs and the equation (4). Next, in the range of SOC 30% to 70%, from the graph (full discharge voltage value) in the complete discharge of the reference discharge map and the graph from 30% to 100% of SOC of the reference charge map (partial charge voltage value) Based on the equation (6) and the partial discharge voltage standard value, a normalized graph is drawn on the partial discharge map, and in the SOC 0% to 30% range, the SOC 70% to 0% of the reference discharge map The graph of the portion of SOC 0% to 30% of the graph in discharge is drawn on the partial discharge map. The graph shown in FIG. 8 is obtained by the above-described procedure of obtaining a partial discharge voltage standard value and drawing a normalized graph based on the standard value when partial charge is performed from SOC 30% to 70%. It is a graph drawn on a partial discharge map.

  As a result of repeating charge and discharge, partial discharge is performed up to SOC 30%, and then partial discharge is performed up to SOC 70%, not the graph from SOC 30% to 100% of the reference charge map of FIG. It is preferable to use a graph of SOC 30% to 100% of the partial charge map drawn / updated in the procedure of This is because the partial charge map is drawn / updated based on the charge / discharge history of the secondary battery, unlike the reference charge map showing the initial state of the secondary battery, thus reflecting the current state of the secondary battery more It is because it has become a thing. In this embodiment, the partial discharge map is updated using the graph of the complete discharge of the reference discharge map of FIG. 5B and the graph of SOC 30% to 100% of the drawn / updated partial charge map of FIG. (Redraw) As described above, by updating the partial discharge map, even when partial charging and discharging are repeated many times, it is possible to obtain an accurate instantaneous SOC estimation value from the open circuit voltage value at the time of discharge.

If a graph (charge / discharge characteristic data) corresponding to the charge switching SOC or the discharge switching SOC is not prepared in the reference charge map, the reference discharge map, the partial charge map, or the partial discharge map, from the already prepared graph, Select one each with the closest value to the charge switching SOC or the discharge switching SOC, and have a graph, and divide the partial charge characteristic data and the partial discharge characteristic data proportionally to select the charge switching SOC or A graph corresponding to the discharge switching SOC is created in the partial charge map / partial discharge map. For example, as shown in FIG. 9, the discharge switching SOC is a%, and the nearest one higher than this, and the discharge switching SOC value with a graph is b%, the nearest nearest one with a graph, the discharge switching When the SOC value is c%, the discharge switching SOC is calculated according to the following equation (7) using the ratio X = (b−a) / (b−c) of the SOC value corresponding to the open circuit voltage value at the time of discharge switching. Create a graph corresponding to the value a% in the partial charge map.
Open circuit voltage = (Open circuit voltage of switching SOC value c%) × X
+ (Open circuit voltage of switching SOC value b%) × (1-X) (7)

  Similarly, at the time of switching from partial discharge to partial charge, partial charge characteristic data of SOC values adjacent to upper and lower sides of the charge switching SOC are proportionally divided, and a graph corresponding to the charge switching SOC is created in the partial discharge map. As described above, by updating the partial charge map and the partial discharge map as needed, it is possible to obtain the more accurate instantaneous SOC estimated value from the open circuit voltage value.

  As shown in FIG. 4, in the present embodiment, at the time of switching from charge to discharge, instantaneous charging is performed when either the duration of charge in the last charge or the change in charge current integration amount exceeds a predetermined value. State map update block 3 updates the partial charge map. Further, at the time of switching from discharge to charge, the instantaneous charge state map update block 3 updates the partial discharge map when either the duration of the last discharge or the change in the discharge current integrated amount exceeds a predetermined value.

Specifically, at the time of switching from partial charge to partial discharge, the map update determination block 23 determines whether one of the following update conditions (a) and (b) is satisfied.
(A): The charging current continues to flow for a predetermined set time or more.
(B): While the charging current continues to flow, the MAP integrated SOC (described later) increases by a predetermined amount or more.
When the above update condition is satisfied, the instantaneous charge state map update block 3 updates the partial charge map by the above-described method, using the control SOC estimated value obtained one calculation flow before as the discharge switching SOC.

Similarly, at the time of switching from partial discharge to partial charge, the map update determination block 23 determines whether any of the following update conditions (c) and (d) are satisfied.
(C): A discharge current continuously flows for a predetermined set time or more.
(D): While the discharge current continues to flow, the MAP integrated SOC decreases by a predetermined amount or more.
When the above update condition is satisfied, the instantaneous charge state map update block 3 updates the partial charge map by the above-described method, using the control SOC estimated value obtained one calculation flow before as the charge switching SOC.

  Here, the map update determination block 23 can confirm the duration of charge or the duration of discharge by, for example, confirming the measured current value and time stored in the storage device (not shown) after step S1. It can be determined whether the update conditions (a) and (c) are satisfied.

In addition, in the update conditions (a) and (c) by the map update determination block 23, it is also possible to use first-order delay calculation of the current. In the present embodiment, the current first-order delay value calculation block 25 performs first-order delay processing using a time constant (first-order delay time constant: Tf) to the measured current value measured in step S1 to calculate the first-order current delay value. The map update determination block 23 determines whether the update conditions (a) and (c) are satisfied, using the current primary delay value as a charging current value or a discharging current value. The current first-order lag value is calculated by the following equation (8). The calculated first-order current delay value is stored, for example, in a storage device (not shown) because it is used as the first-order current delay value previous value after one calculation flow. In addition, the current first-order lag previous value can be set to 0 at the first time of calculation of the current first-order lag value.
Current primary delay value = Current primary delay value previous value
+ (Measured current value-current first-order lag value previous value) / Tf (8)
When charge and discharge are switched in a short cycle, the update conditions (a) and (c) are not satisfied. At this time, charge and discharge are frequently switched, but looking at the entire predetermined set time, it is a case where the SOC of the secondary battery is changed as in the case where the charge and discharge current flows continuously. Also, since the update conditions (a) and (c) are not satisfied, the map update determination block 23 may not update the partial charge map or the partial discharge map. Therefore, by using the primary leakage current value as the charging current value or the discharging current value, the map update determination block 23 sets the partial charge map or partial discharge map at an appropriate timing even when charging and discharging are switched in a short cycle. It can be updated.

  In addition, the instantaneous charge state map update block 3 updates the instantaneous charge state map by considering the change in the charge current integrated amount (MAP integrated SOC) in the update conditions (b) and (d) by the map update determination block 23 The timing to perform can be more appropriate timing, not just every time the state changes from charge to discharge and from discharge to charge.

  The adjustment of the timing of instantaneous charge state map update is not necessarily limited to the above method, but the instantaneous charge state map should be updated when either the charge / discharge duration time or the charge / discharge current integration amount exceeds a predetermined value. Thus, the instantaneous charge state map can be updated at an appropriate timing according to the type and application of the secondary battery, the charge and discharge pattern, and the like. In particular, by using the current first-order delay value obtained by performing first-order delay processing on the current value to determine the duration of charge and discharge, the secondary battery system where absorption of regenerative power and complementation of power running power frequently occur is connected. Update the instantaneous charge condition map more appropriately in applications such as railway substations where charging and discharging are switched in a short cycle, and in applications where output using natural energy such as wind power and solar power is not stable over time It is possible to determine the timing of

  Next, the instantaneous charge state estimation block 5 calculates an instantaneous SOC estimated value based on the instantaneous charge state map updated in step S4 and the open circuit voltage value obtained in step S3 (step S5). In the present embodiment, it is determined from the measured current value measured in step S1 whether the charging state or the discharging state, and in the case of charging, the reference charging map and partial charging map, and in the case of discharging, the reference discharging map and partial discharge map. Then, an instantaneous SOC estimated value is calculated from the open circuit voltage value.

  In the third stage, a current integrated SOC estimated value is obtained. In the third step of this embodiment, the MAP integrated SOC is obtained based on the charging efficiency and the current integrated value, and this is used as the current integrated SOC estimated value.

  Before the first stage, that is, before starting the monitoring of the SOC of the secondary battery, the charging efficiency is determined. The charge efficiency refers to the percentage of the amount of discharge current to the amount of charge current. The measurement of the charge efficiency is performed by charging at a constant current value for a predetermined time and then discharging to determine the charge current amount and the discharge current amount, and calculating the charge efficiency from this. The charging efficiency varies depending on the battery temperature and the SOC, so the battery temperature and the SOC range to be charged and discharged are changed to repeatedly measure the charging efficiency, create a charging efficiency map, and store it in a storage device (not shown). The charge efficiency map can be, for example, as shown in FIG. 10, an aspect of charge efficiency (%) associated with the battery temperature and the SOC. It should be noted that creation of the charge efficiency map may be created using a method such as linear interpolation as in the case where the internal resistance value is not found in the internal resistance characteristic map.

The charge efficiency calculation block 27 calculates the charge efficiency based on the battery temperature measured in step S1, the control SOC estimated value obtained before one calculation flow, and the charge efficiency map (step S6). Next, the current integration charge state estimation block 7 calculates MAP integration SOC according to the following expression (9) using the charging efficiency calculated by the charging efficiency calculation block 27 (step S7). The calculated MAP integrated SOC is, for example, used as the MAP integrated SOC previous value after one calculation flow, and thus is stored in a storage device (not shown).
MAP integrated SOC (%) = MAP integrated SOC previous value (%)
+ (Change amount of charge efficiency × current integrated SOC (%)) (9)

  Here, the “current integration SOC (%)” means an SOC estimated value calculated by integrating the current values flowing through the battery with the charging efficiency being 1. The current integration SOC is a charging state calculated based only on the current integration value, and can be obtained by various methods proposed conventionally. Further, the amount of change of the current integration SOC (%) is a difference between the current integration SOC (%) and the current integration SOC (%) one calculation flow before. The present current integration SOC (%) is stored in a storage device (not shown), for example, because it is used to obtain the amount of change of the current integration SOC (%) after one calculation flow.

  When this calculation flow is the first time, since there is no previous one calculation flow, there is no MAP integrated SOC (%) or current integrated SOC (%). In this case, since the same measures as when there is no control SOC estimated value may be performed in step S2, the details will be omitted.

  The current integrated SOC estimated value may be determined based on a current integrated value obtained by integrating the current value flowing through the battery. However, the estimation accuracy of the current integration SOC estimated value can be enhanced by using the MAP integration SOC which is a value in consideration of the charging efficiency of the secondary battery as described above.

  Finally, in the fourth stage, the control SOC estimated value is obtained and output. In the fourth step, first, the control charge state estimation block 9 uses the time constant (control SOC calculation time constant: Tc) which is set according to the region of the charge state, to estimate the instantaneous charge state estimated value and the current. A control SOC estimated value which is a final charge state estimated value is calculated based on the integrated value (step S8).

Specifically, the instantaneous SOC estimated value calculated in step S5, the control SOC estimated value previous value stored in the storage device (not shown), the MAP integrated SOC calculated in step S6, and the storage device (not shown) From the MAP integration SOC previous value, the control SOC estimated value is determined by the following equation (10).
Control SOC estimated value (%)
= Control SOC estimated value previous value (%) + (MAP integrated SOC (%)-MAP integrated SOC previous value (%))
+ {Instant SOC estimated value (%)-(control SOC estimated value previous value (%) + (MAP integrated SOC (%)-MAP integrated SOC previous value (%))} / Tc
(10)

However, when the control SOC estimated value calculated by equation (10) exceeds a predetermined set value (for example, 100), it is preferable to use the value obtained by the following equation (11) as the control SOC estimated value.
Control SOC estimated value (%) =
= Control SOC estimated value previous value (%) + (MAP integrated SOC (%)-MAP integrated SOC previous value (%))
+ {Instant SOC estimated value (%)-(control SOC estimated value previous value (%) + (MAP integrated SOC (%)-MAP integrated SOC previous value (%))} / Tc
Amount of change in + accumulated current SOC (%)
(11)

  Once charging exceeding the calculable range of the instantaneous SOC estimated value is performed, the calculated value of the instantaneous SOC estimated value obtained in step S5 tends to remain high as it is. As a result, even if the secondary battery is continuously charged and the current integrated value increases, the control SOC estimated value calculated by the equation (10) does not change, which may lead to an overcharged state of the secondary battery. Therefore, the possibility that the secondary battery will be in the overcharged state can be effectively suppressed by the equation (11), which is modified so that the amount of change of the current integration SOC (%) is also taken into consideration of the equation (10).

  The control SOC calculation time constant Tc used in the equations (10) and (11) can be changed according to the state of charge by the control SOC calculation time constant setter 29, as an example is shown in FIG. It is. For example, it is preferable to set the control SOC calculation time constant Tc to a small value and increase the contribution rate of the instantaneous SOC estimated value based on the open circuit voltage in a region where the voltage change amount with respect to the change of the charge state is large. On the other hand, in a region where the amount of voltage change with respect to the change in the state of charge is small, the instantaneous SOC estimated value greatly changes due to a minute change in open circuit voltage. Therefore, control SOC calculation time constant Tc is set to a large value and It is preferable to reduce the contribution rate of the instantaneous SOC estimation value and increase the contribution rate of the current integration SOC estimation value based on the current integration.

  For example, as in a nickel-hydrogen secondary battery, a secondary that has a characteristic that the voltage change to the change of the charge state is large in the shallow region and the deep region of the charge state and the voltage change to the change of the charge state is small in the middle region of the charge state When applied to a battery, the control SOC calculation time constant Tc is set to a small value, for example 900, in the shallow region (0 to 15%) and the deep region (85 to 100%) of the charged state, and the intermediate region of the charged state At (30 to 70%), the control SOC calculation time constant Tc is set to a large value, for example, 3600. In the 15-30% and 70-85% state of charge, a linearly interpolated time constant is set.

  Further, control SOC calculation time constant setting unit 29 sets control SOC calculation time constant Tc to, for example, a change in the state of charge with respect to a plurality of predetermined charge state regions between 0% and 100% in the instantaneous charge state map. The voltage change rate is calculated and automatically set by calculating and setting time constants in the respective charge state regions from the voltage change rate and a predetermined decreasing function of the voltage change rate with respect to the charge state change. Is also possible. More specifically, the control SOC calculation time constant Tc is set as follows.

  First, the control SOC calculation time constant setting unit 29 creates a time constant calculating SOC graph and stores it in a storage device (not shown). Although various SOC graphs for time constant calculation can be used, for example, the graph for the complete charging of the reference charge map of FIG. 5A and the graph of FIG. The SOC graph for calculating the time constant shown in FIG. 12, which is equally distributed with the graph in the complete discharge of the reference discharge map, may be created and stored in a storage device (not shown). Second, the control SOC calculation time constant setter 29 associates the state of charge with the control SOC calculation time constant Tc from the predetermined decreasing function for calculating the control SOC calculation time constant Tc and the time constant calculation SOC graph. A graph is created and stored in a storage device (not shown). For example, in the case of the SOC graph for time constant calculation shown in FIG. 12, the voltage change amount (ΔV) is small in the middle region (30 to 70%) of the charge state even if a slight change (ΔSOC) occurs in the charge state. . On the other hand, in a shallow area (0 to 15%) of the charged state and a deep area (85 to 100%) of the charged state, the amount of voltage change (ΔV) when a minute change (ΔSOC) occurs in the charged state is large.

  The decrease function is a decrease function that calculates the control SOC calculation time constant Tc so as to have a negative correlation with the voltage change rate (ΔV / ΔSOC) with respect to the charge state change. Since the voltage change rate (ΔV / ΔSOC) with respect to the charge state change is small in the middle region of the charge state by this decrease function, a large value, for example, 3600, is calculated for the control SOC calculation time constant Tc. Similarly, with this decreasing function, the voltage change rate (ΔV / ΔSOC) with respect to charge state change is large in the shallow area (0 to 15%) of the charge state and the deep area (85 to 100%) of the charge state. A small value (for example, 900) is calculated for the SOC calculation time constant Tc. In addition, in a 15 to 30% and 70 to 85% range of charge condition, setting of a time constant is not restricted to linear interpolation, and can use various methods by using an appropriate decreasing function. Third, after the control SOC calculation time constant setter 29 calculates the control SOC calculation time constant Tc corresponding to an arbitrary charge state region in the charge state range of 0 to 100%, the control SOC calculation time constant setter 29 A graph correlating the control SOC calculation time constant Tc is created and stored in a storage device (not shown).

  Thereafter, control charge state estimation block 9 obtains a control SOC estimated value by equation (10) or equation (11), but control SOC calculation time constant Tc of equation (10) or equation (11) is stored not shown Based on the control SOC estimated value previous value stored in the device, it is determined from the graph shown in FIG. 11 that associates the SOC shown in FIG. 11 with the time constant Tc created by the control SOC calculation time constant setting unit 29 described above.

  When calculating the control SOC estimated value, the control SOC calculation time constant Tc may not be used. However, by using this time constant Tc, the estimated amount based on the open circuit voltage for the secondary battery in which the amount of change in the open circuit voltage value with respect to the change in the charge state varies greatly depending on the area of the charge state. A control SOC estimated value can be calculated in which the contribution ratio of the value and the contribution ratio of the estimated value based on the current integrated value are appropriately adjusted.

  Furthermore, it is preferable that the control SOC calculation time constant Tc be corrected according to the length of the pause time between charging and discharging. This is because the open circuit voltage of the secondary battery also changes depending on the rest time after the charge and discharge stop, so it is necessary to reduce the contribution rate of the estimated value calculated based on the open circuit voltage. In particular, when the pause time after the charge / discharge stop of the secondary battery is long, the time until the open circuit voltage same as the open circuit voltage before the charge / discharge stop is obtained can be obtained even if the charge / discharge is resumed, ie, the secondary battery Since the time until the state of 回復 recovers becomes long, it affects the estimated value calculated based on the open circuit voltage. Therefore, it is preferable to give a positive correlation between the time constant Tc and the rest time after the charge and discharge stop of the secondary battery.

  Here, the stop time can be determined by detecting the charge / discharge stop by the current measuring instrument 13 and measuring this time by the clocking means (not shown) and storing it in the storage device (not shown). Further, a control function is calculated taking into consideration the pause time from the pause time determined as described above, the increase function to the pause time, and the control SOC calculation time constant Tc at the present time. A time constant Tc 'may be derived and used as a new control SOC calculation time constant. Note that the increase function may be one that obtains the addition value of the control SOC calculation time constant Tc with respect to the pause time. If the pause time is 0, the increment value may be 0 (no change in Tc) with respect to the time constant Tc, the increment value may be 100 for the 10 minutes, and 300 for the 20 minutes. . Further, the increase function may be to obtain a multiplication factor of the control SOC calculation time constant Tc with respect to the pause time. For example, if the pause time is 0, the multiplication factor for the time constant Tc is 1 (no change in Tc), the multiplication factor is 1.1 for 10 minutes, and the multiplication factor is 1.3 for 20 minutes. It may be. The increasing function is not limited to these, and can take various forms. By doing this, as the pause time becomes longer, the control SOC calculation time constant Tc can be corrected to become a large value, and a more accurate estimation can be made in consideration of the influence of the pause time between charge and discharge. It becomes possible.

  Furthermore, it is preferable that the control SOC calculation time constant Tc be corrected according to the charge / discharge current value of the secondary battery. Specifically, when the charge / discharge current value is large, the contribution rate of the estimated value calculated based on the open circuit voltage is reduced by setting the value of control SOC calculation time constant Tc large, and the SOC estimated value based on current integration is It is preferable to increase the contribution rate.

  As in the relationship between the open circuit voltage and the estimated charge state value when the charge current value shown in FIG. 13 is changed, the open circuit voltage value at a predetermined SOC during high current charging (for example, 1.0 C) It tends to be higher than the voltage value obtained based on the graph at the time of 0.2 C charge). Further, as shown in FIG. 14, as in the relationship between the open circuit voltage and the estimated charge state value when the discharge current value is changed, the open circuit voltage value at a predetermined SOC during the large current discharge (for example, 1.0 C) It tends to be lower than the voltage value obtained based on the map (graph at the time of 0.2 C discharge). In this case, when the SOC estimated value is calculated using the reference charge map or the reference discharge map, a value deviated from the actual SOC is calculated. Therefore, the accuracy of the SOC estimated value calculated based on the open circuit voltage during large current charging and discharging Is worse. Therefore, it is preferable to give a positive correlation between the charge / discharge current value of the secondary battery and the control SOC calculation time constant Tc. Furthermore, a predetermined increase function for the charge / discharge current value of the secondary battery is prepared, and a control SOC calculation time constant Tc ′ ′ considering the charge / discharge current value from the increase function and the control SOC calculation time constant Tc at the present time May be derived as a new control SOC calculation time constant. Here, the increase function may be, for example, one for obtaining an addition value of control SOC calculation time constant Tc to the charge / discharge current value, or one for obtaining a multiplication factor of control SOC calculation time constant Tc to the charge / discharge current value. . The increasing function is not limited to these, and can take various forms. As described above, by correcting the control SOC calculation time constant Tc according to the magnitude of the charge and discharge current, it is possible to suppress an increase in the error of the SOC estimated value calculated based on the open circuit voltage.

  Next, the control SOC estimated value calculated in step S8 is output (step S9). Since the control SOC estimated value is used after one calculation flow, it is stored in a storage device (not shown).

  The calculation flow described above can be variously modified in order to estimate the state of charge with higher accuracy.

  For example, in the internal resistance characteristic map shown in FIG. 3B, a reference value which is an internal resistance value in a reference state (for example, 25.degree. C., SOC 50%) and other states relative to the reference value (e.g. It may constitute combining with the map expressed by multiplication factor. With this configuration, when the internal resistance changes in a certain state (for example, 10 ° C., SOC 10%), the entire internal resistance characteristic map can be rewritten based on the change.

  In the above embodiment, the internal resistance characteristic map is created using the internal resistance value 10 seconds after the start of charge and discharge, but for example, the internal resistance characteristic using the internal resistance value 20 seconds after the start of charge and discharge A map or an internal resistance characteristic map using an internal resistance value 30 seconds after the start of charge and discharge may be separately created and stored in a storage device (not shown). Thus, by measuring the time for switching from the charged state to the discharged state or from the discharged state to the charged state, the time during which the charge / discharge state continues can be determined, and the internal resistance characteristic map corresponding to this duration is used. be able to. As a result, a more appropriate internal resistance value can be obtained, and a more appropriate open circuit voltage value can be obtained, so that the estimation accuracy of the state of charge can be further enhanced.

  As described above, according to the estimation method and estimation device of the charge state according to the present embodiment, the charge state of the secondary battery is determined based on both the open circuit voltage value and the current integration value. Since the calculation is performed, the estimation accuracy of the state of charge of the secondary battery is improved by complementing the case of using the open circuit voltage value in the case of using the current integrated value whose accuracy deteriorates in the long run. Moreover, the relationship between the open circuit voltage value and the estimated charge condition value changes as the charge and discharge are repeated, and based on the charge and discharge history, the instantaneous charge condition map that determines the relationship between the open circuit voltage value and the estimated charge condition value. Since updating is performed, it is possible to estimate the state of charge with higher accuracy.

  As described above, although the preferred embodiments of the present invention have been described with reference to the drawings, various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such is also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 charge state estimation apparatus 3 instantaneous charge state map update block 5 instantaneous charge state estimation block 7 current integration charge state estimation block 9 control charge state estimation block 11 voltage measuring device 13 current measuring device 15 battery temperature measuring device 17 internal resistance value calculation Block 19 Internal resistance reference value calculation block 21 Open voltage calculation block 23 Map update judgment block 25 Current first-order lag value calculation block 27 Charge efficiency calculation block 29 Control SOC calculation time constant setter

Claims (12)

A method of estimating the state of charge of a secondary battery based on an open circuit voltage value and an integrated current value,
Charging characteristics when charging from 0% to 100% of the charge condition after the start of use of the secondary battery, the instantaneous charge condition map defining the relationship between the instantaneous open circuit voltage value at the time of charge condition estimation and the charge condition estimated value Based on the full charge characteristic data which is data and the full discharge characteristic data which is the discharge characteristic data at the time of discharging from 100% of charge state to 0%, partial charging between 0% and 100% of charge state is performed. Normalizing the partial charge / discharge characteristic data, which is discharge data, and updating the instantaneous charge state map using the partial charge / discharge voltage standard value obtained by the standardization;
Calculating an instantaneous charge state estimated value at the time of charge state estimation based on the updated instantaneous charge state map;
Calculating a charge state estimated value based on an integrated value of the current flowing through the secondary battery;
Calculating a control charge state estimate used for control of the secondary battery based on the instantaneous charge state estimate and the charge state estimate based on the current integrated value;
A method of estimating the state of charge of a secondary battery, including: A method of estimating the state of charge of a secondary battery based on an open circuit voltage value and an integrated current value,
Updating an instantaneous charge state map, which determines the relationship between the instantaneous open circuit voltage value at the time of charge state estimation and the charge state estimated value, based on charge / discharge characteristic data after the start of use of the secondary battery,
Calculating an instantaneous charge state estimated value at the time of charge state estimation based on the updated instantaneous charge state map;
Calculating a charge state estimated value based on an integrated value of the current flowing through the secondary battery;
Calculating a control charge state estimate used for control of the secondary battery based on the instantaneous charge state estimate and the charge state estimate based on the current integrated value;
Including
At the time of switching from charging to discharging, the instantaneous charge state map is updated when either the duration of charging in the last charge or the charging current integration amount exceeds a predetermined value, and at the time of switching from discharging to charging, A method of estimating a state of charge of a secondary battery, comprising updating the instantaneous charge state map when any of the duration of discharge and the integrated amount of discharge current exceeds a predetermined value. In the method for estimating the state of charge of a secondary battery according to claim 2 , a primary delay process is performed on the charge / discharge current value using a primary delay time constant to calculate a primary current delay value, and based on the primary current delay value. A method for estimating the state of charge of a secondary battery, comprising determining the duration of charging and the duration of discharging. The method for estimating charge state of a secondary battery according to any one of claims 1 to 3 , wherein a control SOC calculation time constant is set according to a region of the charge state, and the control SOC calculation time constant is used to A secondary battery charging state estimation method, comprising: calculating a control charging state estimation value used to control the secondary battery based on an instantaneous charging state estimation value and a charging state estimation value based on the current integrated value. 5. The method for estimating charge state of a secondary battery according to claim 4 , wherein setting of said control SOC calculation time constant is performed for a plurality of predetermined charge state regions between 0% and 100% in said instantaneous charge state map. Calculating a voltage change rate with respect to a charge state change, and calculating and setting a time constant in each of the charge state regions from the voltage change rate and a predetermined decreasing function of the voltage change rate with respect to the charge state change. Method of estimating charging state of secondary battery. The method for estimating the state of charge of a secondary battery according to claim 4 or 5 , wherein the control SOC calculation time constant is corrected according to the length of the charging / discharging pause time. The method for estimating charge state of a secondary battery according to claim 6 , wherein the control SOC calculation time constant is corrected such that the control SOC calculation time constant and the length of the charging / discharging pause time have a positive correlation. Method of estimating charging state of secondary battery. The method for estimating charge state of a secondary battery according to any one of claims 4 to 7 , wherein the control SOC calculation time constant is corrected according to the magnitude of charge and discharge current. . 9. The secondary battery charge state estimating method according to claim 8 , wherein the control SOC calculation time constant is corrected such that the control SOC calculation time constant and the magnitude of the charge / discharge current have a positive correlation. Battery state of charge estimation method. The method for estimating charge state of a secondary battery according to any one of claims 1 to 9 , further comprising: charging an internal resistance reference value used to calculate the instantaneous open circuit voltage value; A method for estimating the state of charge of a secondary battery, which comprises updating based on discharge characteristic data. An apparatus for estimating the state of charge of a secondary battery based on an open circuit voltage value and an integrated current value,
Charging characteristics when charging from 0% to 100% of the charge condition after the start of use of the secondary battery, the instantaneous charge condition map defining the relationship between the instantaneous open circuit voltage value at the time of charge condition estimation and the charge condition estimated value Based on the full charge characteristic data which is data and the full discharge characteristic data which is the discharge characteristic data at the time of discharging from 100% of charge state to 0%, partial charging between 0% and 100% of charge state is performed. Means for normalizing partial charge / discharge characteristic data, which is discharge data, and updating the instantaneous charge state map using the partial charge / discharge voltage standard value obtained by the standardization;
A means for calculating an instantaneous charge state estimated value at the time of charge state estimation based on the updated instantaneous charge state map;
A means for calculating a charge state estimated value based on an integrated value of the current flowing through the secondary battery;
Means for calculating a control charge state estimate used for control of the secondary battery based on the instantaneous charge state estimate and the charge state estimate based on the current integrated value;
A charge state estimation device for a secondary battery comprising: An apparatus for estimating the state of charge of a secondary battery based on an open circuit voltage value and an integrated current value,
A means for updating an instantaneous charge state map for determining a relationship between an instantaneous open circuit voltage value and a charge state estimated value at the time of charge state estimation, based on charge / discharge characteristic data after the start of use of the secondary battery;
A means for calculating an instantaneous charge state estimated value at the time of charge state estimation based on the updated instantaneous charge state map;
A means for calculating a charge state estimated value based on an integrated value of the current flowing through the secondary battery;
Means for calculating a control charge state estimate used for control of the secondary battery based on the instantaneous charge state estimate and the charge state estimate based on the current integrated value;
Equipped with
The means for updating the instantaneous charge state map updates the instantaneous charge state map when any of the charge duration time and the charge current integration amount in the last charge exceeds a predetermined value at the time of switching from charge to discharge. The apparatus for estimating the state of charge of a secondary battery, which updates the instantaneous charge state map when any of the last time of discharge and the integrated amount of discharge current exceeds a predetermined value at the time of switching from discharge to charge.

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