JP6826152B2 - Secondary battery charge status estimation method and estimation device - Google Patents

Description

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

Conventionally, various rechargeable and dischargeable secondary batteries mainly used as a power source for mobile devices have been proposed. Furthermore, in recent years, large-scale devices equipped with secondary batteries have been developed in consideration of the environment. For example, a vehicle equipped with a secondary battery stores the 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 charge state (SOC: State of Charge) of the secondary battery is highly accurate in order to prevent the secondary battery from becoming unusable due to over-discharging or over-charging. A technique for estimating with is required. Conventionally, as a method of estimating the SOC of a secondary battery, a method of estimating based on the integrated current value obtained by integrating the charge / discharge current values and a method of estimating based on the correlation between the battery open circuit voltage and the SOC have been known. (See, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2005-269824 JP-A-2007-292778

However, the estimation method based on the integrated current value has a problem that the detection error of the current value is accumulated after a long period of operation, and the estimation accuracy of the SOC gradually decreases.

In addition, the method of estimating based on the correlation between the battery open circuit voltage and the SOC has a problem that the SOC estimation accuracy is lowered because the relationship between the open circuit voltage value and the SOC changes by repeating charging and discharging. is there.

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

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

According to this configuration, the charge state of the secondary battery is calculated based on both the open circuit voltage value and the current integrated value. Therefore, when the current integrated value whose accuracy deteriorates in the long term is used, the open circuit voltage value is used. By complementing the case of calculation, the accuracy of estimating the charged state of the secondary battery is improved. Moreover, the relationship between the open circuit voltage value and the estimated charge state value changes as charging and discharging are repeated, and an instantaneous charge state map that defines the relationship between the open circuit voltage value and the estimated charge state value is created based on the charge / discharge history. Since it is updated, it is possible to estimate the charging state with higher accuracy.

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

In the method for estimating the charging state of the secondary battery according to the embodiment of the present invention, when either the charging duration or the integrated charging current amount in the immediately preceding charging exceeds a predetermined value when switching from charging to discharging. It is preferable to update the instantaneous charge state map and update the instantaneous charge state map when either the duration of the immediately preceding discharge or the integrated 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 charging state of the secondary battery according to the embodiment of the present invention, the primary delay processing using the time constant is applied to the charge / discharge current value to calculate the current primary delay value, and the current primary delay value is calculated based on the current primary delay 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, especially in an application in which charging and discharging are switched in a short cycle.

In the method for estimating the charge state of the secondary battery according to the embodiment of the present invention, a time constant is set according to the region of the charge state, and the time constant is used to obtain the instantaneous charge state estimate value and the current integration. It is preferable to calculate the control charge state estimate used for controlling the secondary battery based on the charge state estimate 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 charged state may differ significantly depending on the region of the charged state. According to the above configuration, for such a secondary battery, the contribution rate of the estimated value based on the open circuit voltage and the contribution rate of the estimated value based on the integrated current value are appropriately adjusted according to the region of the charged state. Therefore, the charging state can be estimated with higher accuracy.

In the method for estimating the charge state of the secondary battery according to the embodiment of the present invention, the time constant setting is set for a plurality of predetermined charge state regions between 0% and 100% in the instantaneous charge state map. It includes 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 the predetermined decrease function of the voltage change rate with respect to the charge state change. Is preferable. According to the above configuration, it is possible to easily and appropriately set the time constant according to the charge state region of the secondary battery from the instantaneous charge state map.

In the method for estimating the charge state of the secondary battery according to the embodiment of the present invention, it is preferable to correct the time constant according to the pause time of charge / discharge. 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 changes depending on the pause time after charging / discharging is stopped, but according to the above configuration, it is possible to make a more accurate estimation in consideration of the influence of the pause time between charging / discharging.

In the method for estimating the charge state of the secondary battery according to the embodiment of the present invention, it is preferable to correct the time constant 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 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 for estimating the charge state 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 based on the charge / discharge characteristic data of the secondary battery. It is preferable to update the battery. According to this configuration, the internal resistance value of the secondary battery, which changes due to long-term operation or repeated charging / discharging, is updated based on the charging / discharging history, so that the charging state can be estimated with higher accuracy.

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

It is a block diagram which shows the schematic structure of the charge state estimation device which concerns on one Embodiment of this invention. It is a flow chart which shows the outline of the charge state estimation method which concerns on one Embodiment of this invention. It is a figure which shows the example of the internal resistance value calculation in the charge state estimation method which concerns on one Embodiment of this invention. It is a flow chart which shows the example of the update of the instantaneous charge state map in the charge state estimation method which concerns on one Embodiment of this invention. It is a graph which shows the example of the reference charge / discharge map used for updating the instantaneous charge state map in the charge state 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 state 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 state 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 state 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 state map in the charge state estimation method which concerns on one Embodiment of this invention. It is a table which shows the example of the charge efficiency map used in the charge state 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 state estimation method which concerns on one Embodiment of this invention. This is an example of a graph used for calculating the time constant in the charging state estimation method according to the embodiment of the present invention. It is a graph which shows the example of the relationship between the open circuit voltage value and the charge state estimated value when the charge current value is changed. It is a graph which shows the example of the relationship between the open circuit voltage value and the charge state estimated value when the discharge current value is changed.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but 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 charge state estimation method for 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 integrated current value, and is used as a momentary open voltage value at the time of estimating the charge state. Instantaneous charge status map update block 3 that updates the instantaneous charge status map that determines the relationship with the estimated charge status value based on the charge / discharge characteristic data after the start of use of the secondary battery, based on the updated instantaneous charge status map , Calculate the instantaneous charge state estimate value at the time of charge state estimation. Instantly charge state estimation block 5. Calculate the charge state estimate value based on the integrated value (current integrated value) of the current value flowing through the secondary battery. The control charge state that calculates the control charge state estimate used for controlling the secondary battery based on the current integrated charge state estimation block 7, and the instantaneous charge state estimate and the charge state estimate based on the current integrated value. It includes an estimation block 9. Further, the charging state estimation device 1 includes a storage device (for example, a memory) (for example, a memory) used for storing the integrated current value, and a time measuring means (for example, a clock) (not shown) used for calculating the integrated current value. ing.

FIG. 2 shows a calculation flow of the charging state estimation method according to the present embodiment. The calculation flow consists of the first step of measuring the battery voltage value, the battery current value and the battery temperature, and the instantaneous charge state estimated value from the battery voltage value, the battery current value and the battery temperature value (hereinafter, "instantaneous SOC estimated value"). The second step of obtaining the charge state estimated value based on the current integrated value (hereinafter referred to as "current integrated SOC estimated value"), the instantaneous SOC estimated value, and the current integrated SOC estimation. Based on the value, it includes a fourth step of 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.

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

When constructing a battery module or battery system by combining a plurality of secondary batteries (cells) in series and parallel, the actually measured battery module or battery system voltage value in consideration of the battery module or battery system configuration, The current value and the battery temperature may be converted into a battery voltage value, a battery current value, and a battery temperature for each cell and stored in a storage device (not shown). For example, in the case of a battery module in which a predetermined number of secondary batteries are connected 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. The same applies to the battery current value and battery temperature, so details will be omitted.

In the second stage, the instantaneous SOC estimated value is obtained from the instantaneous charging state map that defines the relationship between the open circuit voltage value and the charged 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 discharged and negative when charged.
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, the secondary battery is charged and discharged for a predetermined time at various charge / discharge current values at a predetermined battery temperature and a predetermined SOC, and the battery voltage value during the charging / discharging is measured. For example, in a secondary battery with a rated capacity of 141Ah, after setting the battery temperature to 10 ° C and SOC to 10%, 70.5A (0.5C)
) Is discharged for 15 seconds, and the battery voltage value is measured 10 seconds after the start of discharge. Next, 70.5A (0.5C)
Charge the battery for 15 seconds and measure the battery voltage value 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 value 10 seconds after the start. Secondly, the internal resistance value of the secondary battery is obtained 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 the battery voltage values corresponding to the respective current values were measured. As shown in FIG. 3 (a). , Battery current value and battery voltage value are plotted. 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 taken as the internal resistance value of the secondary battery. To do.

Third, the first and second steps are repeated while changing the battery temperature and SOC to create an internal resistance characteristic map. In the above 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%. In the same way, the battery temperature and SOC are appropriately changed, and the first and second steps are repeated to complete the internal resistance characteristic map shown in FIG. 3 (b).

The method of calculating the internal resistance value of the secondary battery is not limited to the above method. For example, the internal resistance value at the time of discharge is divided into a positive case (discharge) and a negative current value (charge). -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, the internal resistance value calculation block 17 obtains the internal resistance value from the internal resistance characteristic map based on the battery temperature actually measured in step S1 and the control SOC estimated value (described later) obtained before one calculation flow (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 an SOC of 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%. A method other than linear interpolation may be used.

When this calculation flow is the first time, there is no control SOC estimate because it does not exist before one calculation flow. In this case, the 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 integrated current value of Patent Document 1.

In general, the internal resistance value of a secondary battery deteriorates (increases) by repeating charging and discharging. Further, since the secondary battery has variations in manufacturing, the internal resistance value also varies. Therefore, by continuously updating the internal resistance characteristic map at predetermined time intervals based on the following equation (2), the internal resistance value that periodically reflects the deterioration and variation of the secondary battery can be obtained. It is preferable to do so.
Internal resistance (Ω) = (open circuit 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 actually measured before one calculation flow are internally obtained from the open circuit voltage value before one calculation flow obtained in step S3 (described later) based on these values. The resistance reference value calculation block 19 calculates the internal resistance value using the equation (2). Further, the internal resistance reference value calculation block 19 is based on the battery temperature actually measured before one calculation flow, the control SOC estimated value obtained before one calculation flow, and the calculated internal resistance value, and the battery temperature and SOC ( 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 time. However, in order to estimate the charge state of the secondary battery with high accuracy, the frequency of update is higher. It is preferable, and it is preferable to update it regularly and continuously.

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

In the present embodiment, the instantaneous charge state map update block 3 displays an instantaneous charge state map stored in a storage device (not shown) that determines the relationship between the instantaneous open voltage value at the time of estimating the charge state and the estimated charge state value. Update based on the charge / discharge characteristic data after the start of use of the secondary battery (step S4). The update of this instantaneous charge status map will be described in detail below. In the following description, in order to facilitate understanding, expressions such as "using a graph" and "creating a graph" may be used, but the "graph" here is an object. It refers to the data showing the correlation between the two parameters, and does not necessarily 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 that serves as a reference reference when updating the instantaneous charge state map is created and stored in a storage device (not shown). Store. Specifically, a full charge from 0% to 100% of the charging state, and a partial charging test from a plurality of different charging states to 100% (in FIG. 5A, the charging states are 30%, 40%, 50%, 60). A reference charging map consisting of graphs (charging characteristic data) showing changes in the open circuit voltage value with respect to various charging states is created by performing 5 partial charging tests (%, 70% to 100%). Similarly, a complete discharge from 100% to 0% of the charged state, and a partial discharge test from a plurality of different charged states to 0% (in FIG. 5B, the charged states are 30%, 40%, 50%, 60%, Perform 5 partial discharge tests from 70% to 0%) to create a reference discharge map consisting of graphs (discharge characteristic data) showing changes in the open circuit voltage value with respect to various charging states. 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. The reference charge map and the reference discharge map are not limited to 0.2C, but are created by conducting a test with a desired charge / discharge current value in consideration of embodiments such as 0.1C and 0.01C. Can be done.

Even if the same open circuit voltage value is shown, the charging state differs depending on whether the secondary battery is charging or discharging. For example, according to the reference charging map of FIG. 5A, when the open circuit voltage shows 1.361V, if the instantaneous SOC is 50% to partial charging, the instantaneous SOC is 50% to 100% partial charging. With reference to the graph relating 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 partial discharge is performed from the instantaneous SOC of 70%, the instantaneous SOC is 65% when referring to the graph relating to the partial discharge from the instantaneous SOC of 70% to 0%. It turns out that there is. In this way, it is possible to appropriately obtain 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.

Further, the charging state obtained based on the reference charging map and the reference discharging map by repeating charging and discharging of the secondary battery, particularly in a state where the charging state exceeds 0% and is less than 100%, There will be a deviation from the actual charging state, and the accuracy of estimating the charging state will deteriorate. Therefore, in step S4, the instantaneous charge state map update block 3 includes complete charge characteristic data, which is charge characteristic data when the secondary battery is charged from 0% to 100% of the charge state, and 100% to 0% of the charge state. Based on the complete discharge characteristic data, which is the discharge characteristic data when the secondary battery is discharged, the partial charge / discharge characteristic data, which is the partial charge / discharge data between the charge states of 0% and 100%, is standardized. The instantaneous charge status map is updated using the partial charge / discharge voltage standard values obtained by this standardization. FIG. 4 shows the 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 standardized by the voltage value in full 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 voltage value of partial charge is calculated by the following formula (3), and the standard value of the voltage value of partial discharge is calculated by the following formula (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 charging from SOC 50% 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. 315V, referring to the graph relating to partial charging from SOC 50% to 100% in FIG. 5A, the voltage value at SOC = 60% in partial charging from SOC 50% is 1.361V, so the partial charging standard. 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, a partial charging map is created / updated based on the following equation (5) using the standardized 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 described above, an example is shown in which the voltage value at SOC = 60% in partial charging from SOC 50% is standardized based on the equation (3). By repeating the same procedure, SOC = 50 to 100 in partial charging from SOC 50% based on the reference charge map of FIG. 5 (a), the reference discharge map of FIG. 5 (b), and the equation (3). % Partial charge standard value, then SOC = in partial charge from SOC 50% based on the reference charge map of FIG. 5 (a), the reference discharge map of FIG. 5 (b), and equation (5). The graph shown in FIG. 6 is obtained when the partial charge voltage value of 50 to 100% 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 of the reference charge map may be used.

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

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

As a result of repeating charging and discharging, when partial charging is performed up to SOC 50% and then partial discharging is performed up to SOC 30%, the graph is not from SOC 50% to 0% in the reference discharge map of FIG. 5 (b), but will be described later. It is preferable to use a graph from SOC 50% to 0% of the partial discharge map drawn / updated in the 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 that shows the initial state of the secondary battery, so it more reflects the current state of the secondary battery. Because it is a thing. In the present embodiment, the partial charge map is updated by using the graph of the reference charge map of FIG. 5A in full charge and the graph of the drawn / updated partial discharge map of FIG. 7 from SOC 50% to 0%. (Redraw). As described above, by updating the partial charge map, it is possible to obtain a highly accurate instantaneous SOC estimated value from the open circuit voltage value at the time of charging even when the partial charge / discharge is repeated many times.

Similarly, when switching from discharge to charge, a partial discharge map is created / updated based on the following equation (6) using the standardized 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 when the partial discharge is switched to the partial charge (partial charge start point), the voltage value in the complete discharge or the partial discharge of the reference discharge map may be used.

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

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

As a result of repeating charging and discharging, when partial discharge is performed up to SOC 30% and then partial discharge is performed up to SOC 70%, the graph described above is not used for the graph from SOC 30% to 100% in the reference charge map of FIG. 5 (a). It is preferable to use a graph from 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 that shows the initial state of the secondary battery, so it more reflects the current state of the secondary battery. Because it is a thing. In the present embodiment, the partial discharge map is updated by using the graph of the reference discharge map of FIG. 5 (b) in the complete discharge and the graph of the SOC of the drawn / updated partial charge map of FIG. 8 from SOC 30% to 100%. (Redraw). As described above, by updating the partial discharge map, it is possible to obtain a highly accurate instantaneous SOC estimated value from the open circuit voltage value at the time of discharging even when the partial charging / discharging is repeated many times.

If the graph (charge / discharge characteristic data) corresponding to the charge switching SOC or discharge switching SOC is not prepared in the reference charge map, reference discharge map, partial charge map, or partial discharge map, from the graph already prepared, Select one of the values closest to the top and bottom of the charge switching SOC and discharge switching SOC that have a graph, and divide these partial charge characteristic data and partial discharge characteristic data proportionally to perform charge switching SOC and Create a graph corresponding to the discharge switching SOC in the partial charge map / partial discharge map. For example, as shown in FIG. 9, the discharge switching SOC is a%, the closest one on the higher side has a graphed discharge switching SOC value of b%, and the closest one on the lower side has a graphed discharge switching. When the SOC value is c%, this 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 discharge switching. Create a graph corresponding to the value a% in the partial charge map.
Open-circuit voltage = (open-circuit voltage with switching SOC value c%) x X
+ (Open circuit voltage with switching SOC value b%) x (1-X) (7)

Similarly, when switching from partial discharge to partial charge, the partial charge characteristic data of the SOC values adjacent to the top and bottom of the charge switching SOC are proportionally divided, and a graph corresponding to the charge switching SOC is created in the partial discharge map. By updating the partial charge map and the partial discharge map as needed in this way, 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 when either the charging duration or the change in the integrated charging current amount in the immediately preceding charging exceeds a predetermined value. The 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 immediately preceding discharge or the change in the integrated 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 longer.
(B): While the charging current is continuously flowing, the MAP integrated SOC (described later) increases by a predetermined amount or more.
When the above-mentioned update condition is satisfied, the instantaneous charge state map update block 3 updates the partial charge map by the above-mentioned method, using the control SOC estimated value obtained one calculation flow before as the discharge switching SOC.

Similarly, when 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 continuously flows for a predetermined set time or longer.
(D): While the discharge current continues to flow, the MAP integrated SOC decreases by a predetermined amount or more.
When the above-mentioned update condition is satisfied, the instantaneous charge state map update block 3 updates the partial charge map by the above-mentioned 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 charging or the duration of discharging by, for example, confirming the measured current value and the time stored in a storage device (not shown) after step S1. , It is possible to determine 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 delay calculation of the current can also be used. In the present embodiment, the current primary delay value calculation block 25 calculates the current primary delay value by performing a primary delay process using a time constant (first-order delay time constant: Tf) on the measured current value measured in step S1. The map update determination block 23 determines whether or not the update conditions (a) and (c) are satisfied by using this 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) because it is used as the current primary delay value previous value after one calculation flow, for example. Further, in the first calculation of the current primary delay value, the current primary delay previous value can be set to 0.
Current primary delay value = Current primary delay value Previous value
+ (Actual current value-Current primary delay value Previous value) / Tf (8)
If the charge / discharge is switched in a short cycle, the update conditions (a) and (c) are not satisfied. At this time, the charge / discharge is switched frequently, but when viewed over the entire predetermined set time, the SOC of the secondary battery is changing as in the case where the charge / discharge 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 current primary leakage value as the charge current value or the discharge current value, the map update determination block 23 displays 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.

Further, 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 of the operation can be set to a more appropriate timing, not just every time the state is switched from charging to discharging and discharging to charging.

The adjustment of the timing for updating the instantaneous charge status map is not necessarily limited to the above method, but the instantaneous charge status map should be updated when either the charge / discharge duration or the charge / discharge current integrated amount exceeds a predetermined value. As a result, the instantaneous charge status 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, by using the current primary delay value, which is the current value subjected to primary delay processing, to determine the duration of charge / discharge, a secondary battery system is connected in which absorption of regenerated power and complementation of power running power frequently occur. Update the instantaneous charge status map more appropriately for applications such as railway substations where charging and discharging are switched in a short cycle, and for power generation applications where the output using natural energy such as wind power generation and solar power generation is not stable over time. You can judge the timing to do it.

Next, the instantaneous charge state estimation block 5 calculates the 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 it is in the charged state or the discharged state, and it is based on the reference charge map and the partial charge map in the case of charging and the reference discharge map and the partial discharge map in the case of discharging. Then, the instantaneous SOC estimated value is calculated from the open circuit voltage value.

In the third step, the current integrated SOC estimate 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 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. Charging efficiency refers to the percentage of the amount of discharge current to the amount of charge current. The charging efficiency is measured by charging at a constant current value for a predetermined time, then discharging, obtaining the charging current amount and the discharging current amount, and calculating the charging efficiency from this. Since the charging efficiency differs depending on the battery temperature and SOC, the battery temperature and the SOC range for charging / discharging are changed, the charging efficiency is repeatedly measured, a charging efficiency map is created, and the charging efficiency map is stored in a storage device (not shown). The charge efficiency map can be, for example, an aspect of charge efficiency (%) associated with battery temperature and SOC, as shown in FIG. It should be noted that the charging efficiency map may be created by 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 actually measured in step S1, the control SOC estimated value obtained one calculation flow before, and the charge 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). Since the calculated MAP integrated SOC is used as the previous value of the MAP integrated SOC after one calculation flow, it is stored in a storage device (not shown).
MAP integrated SOC (%) = MAP integrated SOC previous value (%)
+ (Charging efficiency x amount of change in integrated current SOC (%)) (9)

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

When this calculation flow is the first time, there is no MAP integrated SOC (%) or current integrated SOC (%) because it does not exist before one calculation flow. In this case, the same measures as when the control SOC estimated value does not exist in step S2 may be taken, so the details will be omitted.

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

Finally, in the fourth stage, the control SOC estimated value is obtained and output. In the fourth stage, first, the control charge state estimation block 9 uses a time constant (control SOC calculation time constant: Tc) set according to the charge state region, and instantaneous charge state estimate value and current. Based on the integrated value, the control SOC estimated value, which is the 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 a storage device (not shown), the MAP integrated SOC calculated in step S6, and stored in a storage device (not shown). From the MAP integrated SOC previous value, the control SOC estimated value is obtained by the following equation (10).
Control SOC estimate (%)
= 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 the 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 estimate (%) =
= 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
+ Amount of change in integrated current SOC (%)
(11)

Once charging is performed beyond the calculable range of the instantaneous SOC estimated value, 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, it is possible to effectively suppress the possibility that the secondary battery will be in an overcharged state by the equation (11) which is a modification of the equation (10) so as to consider the amount of change in the current integrated SOC (%).

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

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

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

First, the control SOC calculation time constant setting device 29 creates a time constant calculation SOC graph and stores it in a storage device (not shown). Various SOC graphs for calculating the time constant can be used. For example, a graph in full charge of the reference charge map of FIG. 5 (a) and a graph of FIG. 5 (b) stored in a storage device (not shown). A SOC graph for calculating the time constant shown in FIG. 12, which is evenly divided from the graph of the complete discharge of the reference discharge map, may be created and stored in a storage device (not shown). Secondly, the control SOC calculation time constant setting device 29 associates the charging state 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. Create a graph and store it in a storage device (not shown). For example, in the case of the SOC graph for calculating the time constant shown in FIG. 12, in the intermediate region (30 to 70%) of the charged state, the voltage change amount (ΔV) is small even if a slight change (ΔSOC) occurs in the charged state. .. On the other hand, in the shallow region (0 to 15%) of the charged state and the deep region (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 reduction function is a reduction 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 change in charging state. By this decreasing function, since the voltage change rate (ΔV / ΔSOC) with respect to the change in the charging state is small in the intermediate region of the charging 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 charging state is large in the region where the charging state is shallow (0 to 15%) and the region where the charging state is deep (85 to 100%). A small value (for example, 900) is calculated for the SOC calculation time constant Tc. When the charged state is in the range of 15 to 30% and 70 to 85%, the setting of the time constant is not limited to linear interpolation by using an appropriate decreasing function, and various methods can be taken. Third, the control SOC calculation time constant setting device 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 sets the SOC as shown in FIG. A graph associated with the control SOC calculation time constant Tc is created and stored in a storage device (not shown).

After that, the control charge state estimation block 9 obtains the control SOC estimated value by the equation (10) or the equation (11), but the control SOC calculation time constant Tc of the equation (10) or the equation (11) is not shown. Based on the control SOC estimated value stored in the apparatus and the previous value, the SOC shown in FIG. 11 and the time constant Tc are obtained from the graph created by the control SOC calculation time constant setter 29 described above.

It is not necessary to use the control SOC calculation time constant Tc when calculating the control SOC estimated value. However, by using this time constant Tc, for a secondary battery in which the amount of change in the open circuit voltage value with respect to the change in the charged state greatly differs depending on the region of the charged state, the estimation is based on the open voltage according to the region of the charged state. It is possible to calculate a controlled 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.

Further, the control SOC calculation time constant Tc is preferably corrected according to the length of the pause time between charge and discharge. This is because the open circuit voltage of the secondary battery changes depending on the pause time after the charge / discharge stop, so 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 the charging / discharging stop of the secondary battery becomes long, the time until the same opening voltage as the opening voltage before the charging / discharging stop can be obtained even if the charging / discharging is restarted, that is, the secondary battery It takes a long time for the state to recover, which affects the estimated value calculated based on the open circuit voltage. Therefore, it is preferable to have a positive correlation between the pause time after the charging / discharging of the secondary battery is stopped and the time constant Tc.

Here, the pause time can be obtained by detecting the charge / discharge stop with the current measuring device 13, measuring this time with a time measuring means (not shown), and storing it in a storage device (not shown). Further, a predetermined increase function for the pause time is prepared, and the control SOC is calculated in consideration of the pause time from the pause time obtained as described above, the increase function for the pause time, and the current control SOC calculation time constant Tc. The time constant Tc'may be derived and used as a new control SOC calculation time constant. The increase function may be used to obtain the addition value of the control SOC calculation time constant Tc with respect to the pause time. When the pause time is 0, the addition value for the time constant Tc is 0 (no change in Tc), when it is 10 minutes, the addition value is 100, and when it is 20 minutes, the addition value is 300. .. Further, the increase function may be used to obtain the multiplication factor of the control SOC calculation time constant Tc with respect to the rest time. For example, when the pause time is 0, the multiplication factor for the time constant Tc is 1 (T).
(No change in c)) It may be an increasing function in which the multiplication factor is 1.1 in the case of 10 minutes and the multiplication factor is 1.3 in the case of 20 minutes. The increasing function is not limited to these, and can take various forms. By doing so, it is possible to correct the control SOC calculation time constant Tc to become a larger value as the pause time becomes longer, and a more accurate estimation can be made in consideration of the influence of the pause time between charge and discharge. It will be 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 lowered by setting the value of the control SOC calculation time constant Tc large, and the SOC estimated 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 estimated charge state value when the charge current value is changed as shown in FIG. 13, the open circuit voltage value at a predetermined SOC during high current charging (for example, 1.0 C) is a reference charge map ( It tends to be higher than the voltage value obtained based on the graph when charging at 0.2C). Further, as in the relationship between the open circuit voltage and the estimated charge state value when the discharge current value is changed as shown in FIG. 14, at the time of large current discharge (for example, 1.0 C), the open circuit voltage value at a predetermined SOC is the reference discharge. It tends to be lower than the voltage value obtained based on the map (graph at 0.2C discharge). In this case, if the SOC estimated value is calculated using the reference charge map or the reference discharge map, the value deviates 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 / discharging. Get 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. Further, a predetermined increase function with respect to the charge / discharge current value of the secondary battery is prepared, and the control SOC calculation time constant Tc'' considering 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, for example, obtain the addition value of the control SOC calculation time constant Tc with respect to the charge / discharge current value, or may obtain the multiplication factor of the control SOC calculation time constant Tc with respect to the charge / discharge current value. .. The increasing function is not limited to these, and can take various forms. In this way, 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 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 charging state 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 ° C., SOC 50%) and another state are relative values (for example, a difference) to the reference value. It may be configured in combination with a map expressed by (multiplier). 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.

Further, in the above-described embodiment, the internal resistance characteristic map is created by 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 is used. A map or an internal resistance characteristic map using the 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 for switching 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 improved.

As described above, according to the charging state estimation method and the estimating 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 integrated current value. Since the calculation is performed, the estimation accuracy of the charged state of the secondary battery is improved by complementing the case of using the current integrated value whose accuracy deteriorates in the long term with the case of calculating using the open circuit voltage value.
Moreover, the relationship between the open circuit voltage value and the estimated charge state value changes as charging and discharging are repeated, and an instantaneous charge state map that defines the relationship between the open circuit voltage value and the estimated charge state value is created based on the charge / discharge history. Since it is updated, it is possible to estimate the charging state with higher accuracy.

As described above, the preferred embodiment of the present invention has been described with reference to the drawings, but various additions, changes or deletions can be made without departing from the spirit of the present invention. Therefore, such things are also included within the scope of the present invention.

1 Charge state estimation device 3 Instantaneous charge state map update block 5 Instantaneous charge state estimation block 7 Current integrated 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 judgment block 25 Current primary delay value calculation block 27 Charging efficiency calculation block 29 Control SOC calculation time constant setter

Claims (9)

It is a method of estimating the charge state of the secondary battery based on the open circuit voltage value and the integrated current value.
The instantaneous charge state map that defines the relationship between the instantaneous open circuit voltage value at the time of estimating charged state and the charging state estimate, at least one of when switching to the charging from the switching and discharging to the discharge from the charging, the switching It can be updated by creating the instantaneous charge state map after the switching based on the partial charge / discharge history data showing the change history of the charge state with respect to the previous open circuit voltage value .
Based on the updated instantaneous charge status map, the instantaneous charge status estimate at the time of charge status estimation can be calculated, and
To calculate the estimated charge state based on the integrated value of the current flowing through the secondary battery,
To calculate the control charge state estimate used for controlling the secondary battery based on the momentary charge state estimate and the charge state estimate based on the current integrated value.
A method for estimating the state of charge of a secondary battery including. In the method for estimating the charge state of the secondary battery according to claim 1,
When switching from charging to discharging, the partial charging characteristic data between the charging state of 0% and 100% before the switching is used as the partial charging / discharging history data, and the momentary use after the switching is performed. Create a charge status map and
When switching from discharge to charge, the partial discharge characteristic data between the charge state of 0% and 100% before the switch is used as the partial charge / discharge history data, and the momentary use after the switch is performed. Create a charge status map,
A method for estimating the charge status of a secondary battery. In the method for estimating the charge state of the secondary battery according to claim 1 or 2.
When switching from charging to discharging, the instantaneous charging state map is used for the region exceeding the charging state at the time of switching, using the charging characteristic data of the reference charging map created before the start of the first charging / discharging of the secondary battery. Create and
When switching from discharge to charge, the region lower than the charge state at the time of switching is the instantaneous charge state using the discharge characteristic data of the reference discharge map created before the start of the first charge / discharge of the secondary battery. Create a map,
A method for estimating the charge status of a secondary battery. It is a method of estimating the charge state of the secondary battery based on the open circuit voltage value and the integrated current value.
Switching from charging to discharging based on the charge / discharge characteristic data after the start of use of the secondary battery, the instantaneous charge state map that defines the relationship between the instantaneous open voltage value at the time of charge state estimation and the charge state estimate. Updating and updating at least one of the time and when switching from discharging to charging
Based on the updated instantaneous charge status map, the instantaneous charge status estimate at the time of charge status estimation can be calculated, and
To calculate the estimated charge state based on the integrated value of the current flowing through the secondary battery,
The control SOC calculation time constant is set according to the charge state region, and the control SOC calculation time constant is used to describe the above two based on the instantaneous charge state estimate value and the charge state estimate value based on the current integrated value. To calculate the control charge state estimate used to control the next battery ,
Correcting the control SOC calculation time constant according to the charge / discharge pause time so that the control SOC calculation time constant and the charge / discharge pause time have a positive correlation.
including,
A method for estimating the charge status of a secondary battery. In the method for estimating the charge state of the secondary battery according to claim 4 , the control SOC calculation time constant is set for a plurality of predetermined charge state regions between 0% and 100% in the instantaneous charge state map. , The voltage change rate with respect to the charge state change is calculated, and the time constant in each charge state region is calculated and set from the voltage change rate and the predetermined decrease function of the voltage change rate with respect to the charge state change. A method for estimating the charge status of a secondary battery. The method for estimating the charge state of a secondary battery according to claim 4 or 5 , wherein the control SOC calculation time constant is corrected according to the magnitude of the charge / discharge current. In the method for estimating the charge state of the secondary battery according to claim 6 , the secondary control SOC calculation time constant is corrected so that the control SOC calculation time constant and the magnitude of the charge / discharge current have a positive correlation. How to estimate the charge status of a battery. A device that estimates the state of charge of a secondary battery based on the open circuit voltage value and the integrated current value.
The instantaneous charge state map that defines the relationship between the instantaneous open circuit voltage value at the time of estimating charged state and the charging state estimate, at least one of when switching to the charging from the switching and discharging to the discharge from the charging, the switching A means for updating by creating the instantaneous charge state map after the switching based on the partial charge / discharge history data showing the change history of the charge state with respect to the previous open circuit voltage value .
A means for calculating an instantaneous charge state estimate at the time of charge state estimation based on the updated instantaneous charge state map, and
A means for calculating an estimated charge state based on the integrated value of the current flowing through the secondary battery, and
A means for calculating a control charge state estimate used for controlling the secondary battery based on the momentary charge state estimate and a charge state estimate based on the current integrated value.
A secondary battery charge state estimation device including. A device that estimates the state of charge of a secondary battery based on the open circuit voltage value and the integrated current value.
Switching from charging to discharging based on the charge / discharge characteristic data after the start of use of the secondary battery, the instantaneous charge state map that defines the relationship between the instantaneous open voltage value at the time of charge state estimation and the charge state estimate. Means to update and at least one of the time and when switching from discharge to charge,
A means for calculating an instantaneous charge state estimate at the time of charge state estimation based on the updated instantaneous charge state map, and
A means for calculating an estimated charge state based on the integrated value of the current flowing through the secondary battery, and
The control SOC calculation time constant is set according to the charge state region, and the control SOC calculation time constant is used to describe the above two based on the instantaneous charge state estimate value and the charge state estimate value based on the current integrated value. A means for calculating the control charge state estimated value used for controlling the next battery, and
A means for correcting the control SOC calculation time constant according to the charge / discharge pause time so that the control SOC calculation time constant and the charge / discharge pause time have a positive correlation.
A secondary battery charge state estimation device.

Images