JP2016114469A - Secondary battery charge state estimation method and secondary battery charge state estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery charge state estimation method and a secondary battery charge state estimation device having high estimation accuracy.SOLUTION: A method for estimating a charge state of a secondary battery on the basis of an open voltage value and a current integrated value, comprises updating an instantaneous charge state map defining a relation between an instantaneous open voltage value and a charge state estimation value at a time of estimating the charge state on the basis of charge/discharge characteristic data after start of using the secondary battery; calculating the instantaneous charge state estimation value at the time of estimating the charge state; calculating a charge state estimation value on the basis of an integrated value of a current flowing in the secondary battery; and calculating a control charge state estimation value for used in control over the secondary battery on the basis of the charge state estimation value based on the instantaneous charge state estimation value and the current integrated value.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, various rechargeable secondary batteries used mainly as a power source for portable devices have been proposed. Furthermore, in recent years, large equipment equipped with a secondary battery has been developed in consideration of the environment. For example, a vehicle equipped with a secondary battery stores regenerative power generated during braking in the secondary battery and uses it as a power source for the vehicle. In addition, the railway substation connected to the overhead line where the secondary battery system is installed absorbs the regenerative power generated by the train and supplements the power running power consumed by the train.

  In these applications, the remaining capacity of the secondary battery, that is, the state of charge of the secondary battery (SOC: State of Charge) is highly accurate in order to prevent the secondary battery from being appropriately used due to overdischarge or overcharge. The technology estimated by Conventionally, as a method for estimating the SOC of a secondary battery, a method for estimating based on a current integrated value obtained by integrating charge / discharge current values, and a method for estimating based on a correlation between battery open voltage and SOC are known. (For example, see Patent Documents 1 and 2).

JP 2005-269824 A JP 2007-292778 A

  However, the estimation method based on the integrated current value has a problem that, when operated for a long period of time, current value detection errors accumulate, and the SOC estimation accuracy gradually decreases.

  Moreover, in the method of estimating based on the correlation between the battery open voltage and the SOC, the relationship between the open voltage value and the SOC changes due to repeated charge and discharge, which reduces the estimation accuracy of the SOC. is there.

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

  In order to achieve the above-described object, a charging state estimation method or estimation device for a secondary battery according to the present invention is a method for estimating a charging state of a secondary battery based on an open-circuit voltage value and a current integrated value. Updating the instantaneous charge state map that defines the relationship between the instantaneous open-circuit voltage value at the time of charge state estimation and the charge state estimated value based on the charge / discharge characteristic data after the start of use of the secondary battery; Based on the instantaneous charge state map, an instantaneous charge state estimated value at the time of charge state estimation is calculated, and based on an integrated value of the current flowing through the secondary battery, a charge state estimated value is calculated, Based on the estimated charge state value and the charge state estimate value based on the current integrated value, the control charge state estimate value used for controlling the secondary battery is calculated.

  According to this configuration, since the state of charge of the secondary battery is calculated based on both the open-circuit voltage value and the current integrated value, the open-circuit voltage value is used when the current integrated value whose accuracy deteriorates in the long term is used. As a result, the estimation accuracy of the charged state of the secondary battery is improved. In addition, the relationship between the open-circuit voltage value and the charge state estimation value changes as charging / discharging is repeated. Based on the charge / discharge history, an instantaneous charge state map that defines the relationship between the open-circuit voltage value and the charge state estimation value is used. Since it is updated, it becomes possible to estimate the state of charge with higher accuracy.

  In the charging state estimation method for a secondary battery according to an embodiment of the present invention, complete charging characteristic data that is charging characteristic data when charging is performed from 0% to 100%, and discharging from 100% to 0% is performed. The partial charge / discharge characteristic data, which is partial charge / discharge data between 0% and 100% of the charge state, is normalized with reference to the complete discharge characteristic data that is the discharge characteristic data when It is preferable to update the instantaneous charge state map using the partial charge / discharge voltage standard value. According to this configuration, since the instantaneous charge state map is updated based on the relative relationship between the full charge / discharge characteristics and the partial charge / discharge characteristics as well as the full charge / discharge characteristics, the charge state is estimated with extremely high accuracy. be able to.

  In the method for estimating the state of charge of a secondary battery according to an embodiment of the present invention, at the time of switching from charging to discharging, when either the duration of charging in the immediately preceding charging or the accumulated amount of charging current exceeds a predetermined value It is preferable to update the instantaneous charge state map and update the instantaneous charge state map when either the duration of the previous discharge or the accumulated amount of discharge current exceeds a predetermined value when switching from discharge to charge. . 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 / discharge pattern, and the like.

  In the method for estimating the state of charge of the secondary battery according to the embodiment of the present invention, first-order lag processing using a time constant is performed on the charge / discharge current value to calculate a first-order lag value, and based on the first-order lag value It is preferable to determine the duration of charging and the duration of discharging. According to this configuration, it is possible to determine the timing for updating the instantaneous charge state map more appropriately, particularly in applications in which charging and discharging are switched in a short cycle.

  In the method for estimating the state of charge of a secondary battery according to an 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 set using the time constant. It is preferable to calculate a control charging state estimation value used for controlling the secondary battery based on a charging state estimation value based on the 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 charge state may vary greatly depending on the state of the charge state. According to the above configuration, for such a secondary battery, 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 integrated value are appropriately adjusted according to the state of charge state. Therefore, the state of charge can be estimated with higher accuracy.

  In the charging state estimation method for a secondary battery according to an embodiment of the present invention, the time constant is set for a plurality of predetermined charging state regions between 0% and 100% in the instantaneous charging state map. Calculating a voltage change rate with respect to a charge state change, and calculating and setting a time constant in each charge state region 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 said structure, the setting of the time constant according to the area | region of the charge condition of a secondary battery can be performed simply and appropriately from an instantaneous charge condition map.

  In the method for estimating a state of charge of a secondary battery according to an embodiment of the present invention, it is preferable that the time constant is corrected according to a charge / discharge pause time. More specifically, for example, it is preferable to correct the time constant so that the time constant and the length of the charge / discharge pause time have a positive correlation. The open-circuit voltage of the battery also changes depending on the rest time after stopping charging / discharging, but according to the above configuration, it is possible to estimate with higher accuracy considering the influence of the resting time between charging / discharging.

  In the method for estimating the state of charge of the secondary battery according to the embodiment of the present invention, it is preferable that the time constant is corrected according to the magnitude of the charge / 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 / discharge current have a positive correlation. According to said structure, it can suppress that the error of the SOC estimated value calculated based on an open circuit voltage becomes large.

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

  As described above, according to the charging state estimation method and the estimation device for the secondary battery 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 the 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 charging efficiency map used in the charging condition estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of a setting 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 a charging current value, and a charging 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 charging condition estimated value.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.

  FIG. 1 shows a schematic configuration of a charging state estimation device 1 that executes a secondary battery charging state estimation method according to an embodiment of the present invention. This charging state estimation device 1 is a device that estimates the state of charge (SOC) of a secondary battery based on an open circuit voltage value and an integrated current value. Instantaneous charge state map update block 3 for updating the instantaneous charge state map that defines the relationship with the estimated charge state value based on the charge / discharge characteristic data after the start of use of the secondary battery, based on the updated instantaneous charge state map An instantaneous charge state estimation block 5 for calculating an instantaneous charge state estimation value at the time of charge state estimation, a charge state estimate value is calculated based on an integrated value (current integrated value) of a current value flowing through the secondary battery. Charge state estimation for control used for controlling the secondary battery based on the current accumulated charge state estimation block 7 and the charge state estimated value based on the instantaneous charge state estimated value and the current accumulated value A control charging state estimation block 9 for calculating a value is provided. Further, the charging state estimation device 1 includes a storage device (not shown) used for storage of the current integrated value (for example, a memory) and a time measuring means (for example, a clock) (not shown) used for calculating the current integrated value. ing.

  FIG. 2 shows a calculation flow of the charging state estimation method according to the present embodiment. The calculation flow includes a first stage of measuring the battery voltage value, the battery current value, and the battery temperature, and an instantaneous charge state estimated value (hereinafter referred to as “instantaneous SOC estimated value”) from the battery voltage value, the battery current value, and the battery temperature value. A third stage for obtaining a state of charge estimated value (hereinafter referred to as “current accumulated SOC estimated value”), an instantaneous SOC estimated value, and a current accumulated SOC estimated. And a fourth stage for obtaining and outputting a control charge state estimated value (hereinafter referred to as “control SOC estimated value”) 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 measured 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 calculation flow is started is measured by a time measuring unit (not shown), and this time is stored in a storage device (not shown).

  In addition, when configuring a battery module or a battery system by combining a plurality of secondary batteries (cells) in series and parallel, taking into account the configuration of the battery module or the battery system, the measured voltage value of the battery module or the battery system, The current value and the battery temperature may be converted into a battery voltage value, a battery current value, and a battery temperature in units of cells, 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 a predetermined number as the battery voltage value. Since the battery current value and the battery temperature are the same, the details are omitted.

In the second stage, an instantaneous SOC estimated value is obtained from the instantaneous charge state map that defines the relationship between the open-circuit voltage value and the charge state estimated 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 when discharging and negative when charging.
Open circuit voltage (V) = measured voltage (V) + (internal resistance (Ω) x measured current (A)) (1)

  Here, before the first stage, that is, before starting the monitoring of the SOC of the secondary battery, an internal resistance characteristic map that associates the battery temperature with the SOC and the internal resistance value of the secondary battery is created by the following procedure, Store in a storage device (not shown).

  First, at a predetermined battery temperature and a predetermined SOC, the secondary battery is charged / discharged at various charge / discharge current values for a predetermined time, and the 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 SOC to 10%, 70.5 A (0.5 C) is discharged for 15 seconds, and the battery voltage value 10 seconds after the start of discharge is taking measurement. Next, charge 70.5A (0.5C) for 15 seconds, and measure the battery voltage 10 seconds after the start of charging. Furthermore, 141A (1.0C) is discharged for 15 seconds, 141A (1.0C) is charged for 15 seconds, 282A (2.0C) is discharged for 15 seconds, and 282A (2.0C) is charged for 15 seconds. Measure the battery voltage 10 seconds after the start. Second, the internal resistance value of the secondary battery is obtained from the measured charge / discharge current value and battery voltage value. In the above example, three constant current discharges and three constant current charges were performed while changing the current values, and the battery voltage values corresponding to the respective current values were measured. As shown in FIG. 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 in the voltage value with respect to the change in the current value is obtained by linear approximation, and this slope is calculated as the internal resistance value of the secondary battery. To 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-described example, the internal resistance value r11 when the battery temperature is 10 ° C. and the SOC is 10% is obtained from the internal resistance characteristic map shown in FIG. Similarly, the first and second procedures are repeated by appropriately changing the battery temperature and SOC, and the internal resistance characteristic map shown in FIG. 3B is completed.

  In addition, the calculation method of the internal resistance value of the secondary battery is not limited to the above-described method. For example, the internal resistance value during discharge is divided into a case where the current value is positive (discharge) and a case where the current value is negative (charge). -The internal resistance value during charging may be calculated separately. The approximation method is not limited to linear approximation, and various methods can be employed.

  Next, based on the battery temperature actually measured in step S1 and a control SOC estimated value (described later) obtained one calculation flow before, the internal resistance value calculation block 17 obtains an internal resistance value from the internal resistance characteristic map (step S2). . When 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 obtaining the internal resistance of the battery temperature of 13 ° C. and the control SOC value of 10%, the internal resistance value calculation block 17 has the battery temperature of 10 ° C. and SOC of 10%. The internal resistance value is calculated by linear interpolation from the internal resistance value and the battery temperature of 15 ° C. and the SOC 10% SOC. A method other than linear interpolation may be used.

  When this calculation flow is the first time, there is no control SOC estimated value because there is no 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 such as using an SOC value based on the current integrated value of Patent Document 1 may be used.

In general, the internal resistance value of the secondary battery is deteriorated (increased) by repeated charge and discharge. In addition, since secondary batteries have manufacturing variations, internal resistance values also vary. Therefore, based on the following equation (2), the internal resistance characteristic map is continuously updated at predetermined time intervals so that an internal resistance value that regularly reflects deterioration and variation of the secondary battery can be obtained. It is preferable to do.
Internal resistance (Ω) = (Open voltage (V)-Actual voltage (V)) / Actual current (A) (2)

  In this embodiment, from the battery voltage value, battery current value, and battery temperature measured before one calculation flow, and the open-circuit voltage value before one calculation flow obtained in step S3 (described later) based on these values, the internal The resistance reference value calculation block 19 calculates an internal resistance value using the 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 estimated control SOC 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 does not have to be updated regularly or continuously, and may be updated at any timing. However, in order to estimate the state of charge of the secondary battery with high accuracy, the update frequency should be higher. It is preferable to update regularly and continuously.

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

  In the present embodiment, the instantaneous charge state map update block 3 stores an instantaneous charge state map, which is stored in a storage device (not shown), that defines the relationship between the instantaneous open-circuit voltage value at the time of charge state estimation and the charge state estimated value, Updating is performed based on the charge / discharge characteristic data after the start of use of the secondary battery (step S4). The update of the instantaneous charge state map will be described in detail below. In the following explanation, in order to facilitate understanding, there are cases where explanations are made using expressions such as “use a graph”, “create a graph”, etc. Data indicating the correlation between the two parameters is not necessarily a visually expressed graph. For example, a “graph” may indicate a 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 serving as a reference standard for 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 tests from different charge states to 100% (in FIG. 5A, charge states 30%, 40%, 50%, 60 %, 70% to 100% (5 partial charge tests), and a reference charge map composed of graphs (charge characteristic data) showing changes in open-circuit voltage values for various charge states is created. Similarly, complete discharge from 100% to 0% charge state and partial discharge tests from different charge states to 0% (in FIG. 5B, charge state 30%, 40%, 50%, 60%, (5 partial discharge tests from 70% to 0%) are performed, and a reference discharge map composed of graphs (discharge characteristic data) showing changes in open-circuit voltage values with respect to various charge states is created. In this embodiment, a test is performed with a charge / discharge current of 0.2 C, and a reference charge map / reference discharge map is created. Note that the reference charge map / reference discharge map is not limited to 0.2C, but should be created by testing at a desired charge / discharge current value in consideration of the embodiment such as 0.1C or 0.01C. Can do.

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

  Furthermore, the charging state obtained based on the reference charging map and the reference discharging map by repeating the charging and discharging of the secondary battery, particularly by repeating the charging and discharging in a state where the charging state exceeds 0% and less than 100%, and A deviation occurs from the actual state of charge, and the accuracy of estimation of the state of charge deteriorates. Therefore, in step S4, the instantaneous charge state map update block 3 performs complete charge characteristic data, which is charge characteristic data when the secondary battery is charged from the charge state 0% to 100%, and the charge state 100% to 0%. With reference to the complete discharge characteristic data that is the discharge characteristic data when the secondary battery is discharged, the partial charge / discharge characteristic data that is partial charge / discharge data between 0% and 100% of the charge state is normalized, 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 creating and updating 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 full charge and the voltage value in full 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)

  An example of normalizing the voltage value at SOC = 60% in partial charge from SOC 50% is shown. For example, referring to FIG. 5 (a), the voltage value at SOC = 60% in full charge is 1.390V, and referring to FIG. 5 (b), the voltage value at SOC = 60% in full discharge is 1.V. 315V, referring to the graph relating to the partial charge from SOC 50% to 100% in FIG. 5A, the voltage value at SOC = 60% in the partial charge from the SOC 50% is 1.361 V. The value is (1.361-1.315) / (1.390-1.315) = 0.613 from the above equation (3).

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

  As described above, the example in which the voltage value at SOC = 60% in the partial charge from the SOC 50% is normalized based on the formula (3) has been shown. By repeating the same procedure, SOC = 50 to 100 in partial charge from SOC 50% based on the reference charge map of FIG. 5A, the reference discharge map of FIG. 5B, and equation (3). % Partial charge standard value, and then, based on the reference charge map of FIG. 5A, the reference discharge map of FIG. 5B, and the equation (5), the SOC in the partial charge from SOC 50% = When the partial charge voltage value of 50 to 100% is obtained, a graph shown in FIG. 6 is obtained.

  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 in the reference charge map may be used.

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

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

  In addition, as a result of repeating charge and discharge, when performing partial charge to SOC 50% and then performing partial discharge to SOC 30%, it is not a graph from SOC 50% to 0% of the reference discharge map of FIG. It is preferable to use a graph of SOC 50% to 0% of the partial discharge map drawn / updated in the above 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 indicating the initial state of the secondary battery, and thus more reflects the current state of the secondary battery. It depends on what has become. In the present embodiment, the partial charge map is updated using the graph of the full charge of the reference charge map of FIG. 5A and the graph of 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 / discharge is repeated many times, a highly accurate instantaneous SOC estimated value can be obtained from the open-circuit voltage value during charging.

Similarly, when switching from discharging to charging, the partial discharge map is created / updated based on the following equation (6) using the standardized voltage value.
Partial discharge voltage value = standard value of partial discharge voltage
× (Partial charge voltage value-Complete discharge voltage value)
+ Complete discharge voltage (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), the voltage value in the complete discharge or partial discharge of the reference discharge map may be used.

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

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

  As a result of repeated charge and discharge, when partial discharge is performed up to SOC 30% and then partial discharge is performed up to SOC 70%, the graph is not the graph from SOC 30% to 100% of the reference charge map in 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 indicating the initial state of the secondary battery, and thus reflects the current state of the secondary battery more. It depends on what has become. In the present 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 charge / discharge is repeated many times, an accurate instantaneous SOC estimated value can be obtained from the open-circuit voltage value at the time of discharge.

When the graph (charge / discharge characteristic data) corresponding to the charge switching SOC and the discharge switching SOC is not prepared in the reference charging map, the reference discharging map, the partial charging map, and the partial discharging map, from the already prepared graph, Select one each having a graph that is closest to the top and bottom of the charge switching SOC and the discharge switching SOC, and proportionally apportioning these partial charge characteristic data and partial discharge characteristic data, 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%, the discharge switching SOC value with the graph closest to the higher side is b%, and the discharge switching SOC value with the graph is closest to the lower side and has the graph. When the SOC value is c%, the discharge switching SOC is calculated by the following equation (7) using the ratio X = (ba) / (bc) of the SOC value corresponding to the open circuit voltage value at the time of discharging switching. A graph corresponding to the value a% is created in the partial charge map.
Open circuit voltage = (open circuit voltage of switching SOC value c%) x X
+ (Opening voltage of switching SOC value b%) × (1-X) (7)

  Similarly, when switching from partial discharge to partial charge, the partial charge characteristic data of the SOC values adjacent to the upper and lower sides of the charge switching SOC are proportionally prorated to create a graph corresponding to the charge switching SOC in the partial discharge map. Thus, by updating the partial charge map and the partial discharge map as needed, it is possible to obtain a more accurate instantaneous SOC estimated value from the open-circuit voltage value.

  As shown in FIG. 4, in the present embodiment, when switching from charging to discharging, instantaneous charging is performed if either the duration of charging or the change in accumulated charge current amount in the immediately preceding charging exceeds a predetermined value. The state map update block 3 updates the partial charge map. At the time of switching from discharging to charging, the instantaneous charge state map update block 3 updates the partial discharge map if either the duration of the previous discharge or the change in the accumulated discharge current exceeds a predetermined value.

Specifically, at the time of switching from partial charge to partial discharge, the map update determination block 23 determines whether or not any of the following update conditions (a) and (b) is satisfied.
(A): The charging current continuously flows 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 method using the control SOC estimated value obtained before one calculation flow 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 or not any of the following update conditions (c) and (d) is satisfied.
(C): The discharge current continues to flow 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 method using the control SOC estimated value obtained before one calculation flow as the charge switching SOC.

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

In addition, in the update conditions (a) and (c) by the map update determination block 23, the first-order lag calculation of the current can also be used. In the present embodiment, the current primary delay value calculation block 25 performs primary delay processing using a time constant (first delay time constant: Tf) on the actually measured current value measured in step S1, and calculates a current primary delay value. The map update determination block 23 determines whether or not the update conditions (a) and (c) are satisfied using the current primary delay value as the charge current value or the discharge current value. The current primary delay value is calculated by the following equation (8). The calculated current primary delay value is stored in a storage device (not shown), for example, to be used as the current primary delay value previous value after one calculation flow. In the first calculation of the current primary delay value, the current primary delay previous value can be set to zero.
Current primary delay value = Current primary delay value Previous value
+ (Actually measured current value-current primary delay value previous value) / Tf (8)
When charging / discharging switches in a short cycle, the update conditions (a) and (c) are not satisfied. At this time, charging / discharging is frequently switched, but when the entire predetermined set time is viewed, the SOC of the secondary battery is changing as in the case where the charging / discharging current continuously flows. However, 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 current leakage value as the charging current value or the discharging current value, the map update determination block 23 can display the partial charge map and the partial discharge map at an appropriate timing even when charging / discharging is switched in a short cycle. Can be updated.

  In addition, in the update conditions (b) and (d) by the map update determination block 23, 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). The timing to perform can be set to a more appropriate timing instead of simply switching from charging to discharging and from discharging to charging.

  The timing adjustment of the instantaneous charge state map update is not necessarily limited to the above method, but the instantaneous charge state map is updated when either the charge / discharge duration or the charge / discharge current integrated 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 / discharge pattern, and the like. In particular, a secondary battery system that frequently absorbs regenerative power or complements powering power is connected by using the primary delay value of the primary delay process to determine the duration of charge / discharge. Instantaneous charge state map updated more appropriately for applications where charging and discharging are switched in a short cycle, such as railway substations, and for power generation applications where natural energy output is not stable over time, such as wind power generation and solar power generation The timing to perform can be determined.

  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, whether the charging state or the discharging state is determined from the actually measured current value measured in step S1, is based on the reference charging map and the partial charging map in the case of charging, and based on the reference discharging map and the partial discharging map in the case of discharging. 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 stage of the present embodiment, the MAP integrated SOC based on the charging efficiency and the current integrated value is obtained, and this is set 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 obtained. The charging efficiency is a percentage of the discharge current amount with respect to the charge current amount. The charging efficiency is measured by charging at a constant current value for a predetermined time, then discharging, obtaining a charging current amount and a discharging current amount, and calculating the charging efficiency therefrom. Since the charging efficiency varies depending on the battery temperature and the SOC, the charging efficiency is measured repeatedly by changing the battery temperature and the SOC range to be charged / discharged, and a charging efficiency map is created and stored in a storage device (not shown). For example, as shown in FIG. 10, the charging efficiency map may have a mode of charging efficiency (%) associated with the battery temperature and the SOC. Note that the charging 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 charging efficiency calculation block 27 calculates the charging efficiency based on the battery temperature actually measured in step S1, the control SOC estimated value obtained before one calculation flow, and the charging efficiency map (step S6). Next, the current integrated charging state estimation block 7 calculates the MAP integrated SOC by the following equation (9) using the charging efficiency calculated by the charging efficiency calculation block 27 (step S7). Note that the calculated MAP integrated SOC is stored in a storage device (not shown) because it is used as the previous value of the MAP integrated SOC after one calculation flow, for example.
MAP integrated SOC (%) = MAP integrated SOC previous value (%)
+ (Change in charge efficiency x current integration SOC (%)) (9)

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

  When this calculation flow is the first time, there is no MAP integrated SOC (%) or current integrated SOC (%) because there is no one calculation flow before. In this case, the same action as when no estimated control SOC value is present in step S2 may be performed, and the details are omitted.

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

  Finally, in the fourth stage, a control SOC estimated value is obtained and output. In the fourth stage, first, the control charging state estimation block 9 uses the time constant (control SOC calculation time constant: Tc) set according to the state of the charging state to instantaneously estimate the charging state and current. Based on the integrated value, a control SOC estimated value that is a final charged state estimated value is calculated (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) A control SOC estimated value is obtained from the previous MAP integrated SOC value by the following equation (10).
Control SOC estimated value (%)
= Control SOC estimated value previous value (%) + (MAP integrated SOC (%)-MAP integrated SOC previous value (%))
+ {Instantaneous 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), the value obtained by the following equation (11) is preferably used as the control SOC estimated value.
Control SOC estimated value (%) =
= Control SOC estimated value previous value (%) + (MAP integrated SOC (%)-MAP integrated SOC previous value (%))
+ {Instantaneous SOC Estimated Value (%) − (Control SOC Estimated Value Previous Value (%) + (MAP Integrated SOC (%) − MAP Integrated SOC Previous Value (%))} / Tc
+ Change amount of current integration SOC (%)
(11)

  Once charging exceeding the range where the instantaneous SOC estimated value can be calculated 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, and there is a possibility that the secondary battery is overcharged. Therefore, by revising equation (10) so that the amount of change in current integration SOC (%) is also taken into account, the possibility that the secondary battery will be overcharged can be effectively suppressed.

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

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

  Further, the control SOC calculation time constant setting unit 29 sets the control SOC calculation time constant Tc to the change in the charge state for a plurality of predetermined charge state regions between 0% and 100% in the instantaneous charge state map, for example. The voltage change rate is calculated and automatically set by calculating and setting the time constant in each charge state region from the voltage change rate and a predetermined decrease 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 calculation SOC graph and stores it in a storage device (not shown). Various time constant calculation SOC graphs can be used. For example, the graph for the full charge of the reference charge map of FIG. 5A stored in a storage device (not shown), and the time graph of FIG. A time constant calculating SOC graph shown in FIG. 12 that is equally distributed from the graph of complete discharge in the reference discharge map may be created and stored in a storage device (not shown). Secondly, the control SOC calculation time constant setting unit 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 SOC graph for time constant calculation. A graph is created and stored in a storage device (not shown). For example, in the time constant calculation SOC graph shown in FIG. 12, in the middle region (30 to 70%) of the charged state, the voltage change amount (ΔV) is small even if a minute change (ΔSOC) occurs in the charged state. . On the other hand, in a shallow state (0 to 15%) of the charged state and a deep region (85 to 100%) of the charged state, the voltage change amount (ΔV) when a minute change (ΔSOC) occurs in the charged state is large.

  The decrease function is a decrease function for calculating 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 change in the state of charge. Due to this decreasing function, since the voltage change rate (ΔV / ΔSOC) with respect to the change in the charge state is small in the intermediate region of the charge state, the control SOC calculation time constant Tc is calculated to be a large value, for example, 3600. Similarly, by this decreasing function, the voltage change rate (ΔV / ΔSOC) with respect to the change in the charge state is large in the shallow region (0 to 15%) of the charge state and the deep region (85 to 100%) of the charge state. A small value (for example, 900) is calculated as the SOC calculation time constant Tc. When the state of charge is in the range of 15 to 30% and 70 to 85%, the setting of the time constant is not limited to linear interpolation, and various methods can be taken by using an appropriate decrease function. Thirdly, the control SOC calculation time constant setting unit 29 calculates the control SOC calculation time constant Tc corresponding to an arbitrary charge state region in the range of 0 to 100% of the charge state, and then calculates the SOC shown in FIG. A graph that associates the control SOC calculation time constant Tc is created and stored in a storage device (not shown).

  Thereafter, the control charging state estimation block 9 obtains the control SOC estimated value by the formula (10) or the formula (11), but the control SOC calculation time constant Tc of the formula (10) or the formula (11) is stored in a memory (not shown). Based on the control SOC estimated value previous value stored in the apparatus, the control SOC calculation time constant setting unit 29 generates the SOC shown in FIG. 11 and the time constant Tc, which are associated with each other.

  In calculating the control SOC estimated value, the control SOC calculation time constant Tc may not be used. However, by using this time constant Tc, 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 charge-state region, the estimation based on the open-circuit voltage is performed according to the charge-state region. A control SOC estimated value in which the contribution rate of the value and the contribution rate of the estimated value based on the integrated current value are appropriately adjusted can be calculated.

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

  Here, the charging / discharging stoppage is detected by the current measuring device 13, and this time is measured by a time measuring unit (not shown) and stored in a storage device (not shown), whereby the downtime can be obtained. Further, a predetermined increase function for the pause time is prepared, and the control SOC calculation in consideration of the pause time is calculated from the pause time obtained as described above, the increase function for the pause time, and the current control SOC calculation time constant Tc. A time constant Tc ′ may be derived and used as a new control SOC calculation time constant. Note that the increase function may be a function for obtaining an addition value of the control SOC calculation time constant Tc with respect to the pause time. When the pause time is 0, the added value for the time constant Tc is 0 (no change in Tc), 10 minutes may be an increasing function with the added value being 100, and 20 minutes being the added value being 300. . Further, the increase function may be a function for obtaining a multiplication factor of the control SOC calculation time constant Tc with respect to the pause time. For example, when 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. There may be. The increase function is not limited to these and can take various forms. By doing in this way, it can correct | amend so that control SOC calculation time constant Tc may become a large value as rest time becomes long, and more accurate estimation which considered the influence of rest time between charging / discharging is performed. It becomes possible.

  Further, the control SOC calculation time constant Tc is preferably 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 the control SOC calculation time constant Tc to be large, and the estimated SOC value based on the current integration is reduced. It is preferable to increase the contribution rate.

  As in the relationship between the open-circuit voltage and the charge state estimated value when the charge current value is changed as shown in FIG. 13, the open-circuit voltage value at a predetermined SOC is the reference charge map (at the time of large current charge (for example, 1.0 C)). There is a tendency to be higher than the voltage value obtained based on the graph at 0.2C charge). Further, as in the relationship between the open-circuit voltage and the charge state estimation value when the discharge current value shown in FIG. 14 is changed, the open-circuit voltage value at a predetermined SOC at the time of large current discharge (for example, 1.0 C) is the reference discharge. There is a tendency to be lower than the voltage value obtained based on the map (graph at the time of 0.2C discharge). In this case, if the estimated SOC 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 estimated SOC value calculated based on the open circuit voltage during large current charge / discharge Gets worse. Therefore, it is preferable to have 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 the control SOC calculation time constant Tc '' taking into account the charge / discharge current value from the increase function and the current control SOC calculation time constant Tc. May be derived and used as a new control SOC calculation time constant. The increase function may be, for example, a value obtained by adding the control SOC calculation time constant Tc to the charge / discharge current value, or may be a value obtained by calculating the multiplication factor of the control SOC calculation time constant Tc with respect to the charge / discharge current value. . The increase function is not limited to these and can take various forms. Thus, by correcting the control SOC calculation time constant Tc according to the magnitude of the charge / discharge current, it is possible to suppress an increase in the error of the estimated SOC 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, the internal resistance characteristic map shown in FIG. 3B is a reference value that is an internal resistance value in a reference state (for example, 25 ° C., SOC 50%) and a relative value (for example, a difference or The map may be combined with a map expressed by (multiplier 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 this change.

  In the above-described embodiment, the internal resistance characteristic map is created using the internal resistance value 10 seconds after the start of charging / discharging. For example, the internal resistance characteristic using the internal resistance value 20 seconds after the start of charging / discharging. A map or an internal resistance characteristic map using an internal resistance value 30 seconds after the start of charging / discharging may be separately created and stored in a storage device (not shown). As a result, the time during which the charge / discharge state continues can be obtained by measuring the time from the charge state to the discharge state or from the discharge state to the charge state, 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 charged state can be further increased.

  As described above, according to the charging state estimation method and the estimation device according to the present embodiment, the charging state of the secondary battery is determined based on both the open-circuit voltage value and the current integrated value. Since the calculation is performed, the case where the current integrated value whose accuracy deteriorates in the long term is used is complemented by the case where the calculation is performed using the open-circuit voltage value, thereby improving the estimation accuracy of the charged state of the secondary battery. In addition, the relationship between the open-circuit voltage value and the charge state estimation value changes as charging / discharging is repeated. Based on the charge / discharge history, an instantaneous charge state map that defines the relationship between the open-circuit voltage value and the charge state estimation value is used. Since it is updated, it becomes possible to estimate the state of charge with higher accuracy.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. Therefore, such a thing 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 circuit voltage calculation block 23 Map update determination block 25 Current primary delay value calculation block 27 Charging efficiency calculation block 29 Control SOC calculation time constant setter

Claims (12)

A method for estimating a charge state of a secondary battery based on an open circuit voltage value and an integrated current value,
Updating the instantaneous charge state map that defines the relationship between the instantaneous open-circuit voltage value at the time of charge state estimation and the charge state estimate value, based on charge / discharge characteristic data after the start of use of the secondary battery;
Calculating an instantaneous charge state estimation value at the time of charge state estimation based on the updated instantaneous charge state map;
Calculating an estimated charge state based on an integrated value of the current flowing through the secondary battery;
Calculating a charging state estimation value for control used for controlling the secondary battery based on the instantaneous charging state estimation value and a charging state estimation value based on the current integrated value;
A method for estimating the state of charge of a secondary battery including:   2. The method for estimating the state of charge of a secondary battery according to claim 1, wherein full charge characteristic data as charge characteristic data when charging from 0% to 100% of charge state and discharging from 100% to 0% of charge state are performed. The partial charge / discharge characteristic data, which is 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 of A method for estimating a charge state of a secondary battery, wherein the instantaneous charge state map is updated using a charge / discharge voltage standard value.   3. The method for estimating a state of charge of a secondary battery according to claim 1 or 2, wherein at the time of switching from charging to discharging, either the charging duration or the charging current integrated amount in the immediately preceding charging exceeds a predetermined value. Updating the instantaneous charge state map, and updating the instantaneous charge state map when any of the last discharge duration and the accumulated discharge current exceeds a predetermined value when switching from discharge to charge, Battery charge state estimation method.   4. The method for estimating a state of charge of a secondary battery according to claim 3, wherein a first-order lag process using a time constant is performed on a charge / discharge current value to calculate a first-order lag value, and the charge is performed based on the first-order lag value. The charge state estimation method of a secondary battery which determines the continuation time and discharge continuation time.   5. The method for estimating the state of charge of a secondary battery according to claim 1, wherein a time constant is set according to a region of the state of charge, and the instantaneous state of charge is estimated using the time constant. A charging state estimation method for a secondary battery, wherein a charging state estimation value for control used for controlling the secondary battery is calculated based on a value and a charging state estimation value based on the integrated current value.   6. The method for estimating a charge state of a secondary battery according to claim 5, wherein the time constant is set for a plurality of predetermined charge state regions between 0% and 100% in the instantaneous charge state map. A secondary battery comprising: calculating a voltage change rate with respect to a change, and calculating and setting a time constant in each charge state region from the voltage change rate and a predetermined decreasing function of the voltage change rate with respect to the charge state change Charging state estimation method.   The method for estimating the state of charge of a secondary battery according to claim 5 or 6, wherein the time constant is corrected in accordance with the length of charge / discharge downtime.   8. The secondary battery charge state estimation method according to claim 7, wherein the time constant is corrected so that the time constant has a positive correlation with the length of the charge / discharge pause time. Estimation method.   9. The secondary battery charge state estimation method according to claim 5, wherein the time constant is corrected according to a charge / discharge current magnitude. 10.   The method for estimating the state of charge of a secondary battery according to claim 9, wherein the time constant is corrected so that the time constant and the magnitude of the charge / discharge current have a positive correlation. .   11. The method for estimating a state of charge of a secondary battery according to claim 1, wherein an internal resistance reference value used for calculating the instantaneous open-circuit voltage value is a charge value of the secondary battery. A method for estimating a state of charge of a secondary battery including 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 a current integrated value,
Means for updating an instantaneous charge state map that defines a relationship between an instantaneous open-circuit voltage value at the time of charge state estimation and a charge state estimate value based on charge / discharge characteristic data after the start of use of the secondary battery;
Means for calculating an instantaneous charge state estimation value at the time of charge state estimation based on the updated instantaneous charge state map;
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 charging state estimation value used for controlling the secondary battery based on the instantaneous charging state estimation value and a charging state estimation value based on the current integrated value;
A charging state estimation device for a secondary battery comprising:

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