Battery control system, power supply and demand system equipped with the same, battery control method, and battery control program

Abstract

To provide a battery control system, a power supply and demand system equipped with the same battery control method, and a battery control program that can suppress variations in the charging rate of each storage battery and extend the life of the storage battery and the system.SOLUTION: A battery control system applied to a battery system having a plurality of storage batteries includes an overall average calculation unit 72 that calculates an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period, an individual average calculation unit 71 that calculates an individual average charging rate for each storage battery using charging rate data for each storage battery over a predetermined period, an offset calculation unit 73 that calculates an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate, and a power command setting unit that sets an individual power command for each storage battery using the individual offset power for each storage battery.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a battery control system, a power supply and demand system including the battery control system, a battery control method, and a battery control program. [Background technology]

[0002] Nowadays, in various environments where electric power is used, such as industrial plants, a power supply is stabilized by providing a storage battery capable of storing electric power in addition to the power supply source in case the power supply from the power supply source is stopped or a large power supply is required locally. In addition, since deterioration over time is unavoidable due to the nature of the storage battery, various methods for extending the life of the storage battery and for accurately estimating the life of the storage battery are being considered.

[0003] Patent Document 1 discloses a method of deriving a linear equation for the current-voltage characteristics of a storage battery from the current and voltage of the storage battery at a specified temperature, and estimating the state of charge and / or state of deterioration of the storage battery using the slope and intercept. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-345135 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 only discloses a method for estimating the state of charge and / or state of deterioration of a single storage battery, and does not disclose controlling the charge / discharge current and / or charging rate (hereinafter referred to as "SOC (State of Charge)") of each storage battery taking into account the operating mode and state of deterioration of each storage battery when power is shared among multiple storage batteries.

[0006] For this reason, in a system that operates multiple storage batteries, when the storage batteries are used for a long period of time, the charging rates of the storage batteries will vary. If the operation of the storage batteries continues without eliminating the variations, the central values ​​of the charging rates of the storage batteries will shift, and the maximum charging rate of the storage batteries will approach the upper operational limit, or the minimum charging rate of the storage batteries will approach the lower operational limit.

[0007] There are several reasons why the charging rates of multiple storage batteries approach the upper or lower operational limit. For example, when power sharing is performed with different allocations for each storage battery, the charging rates of each storage battery approach the upper or lower operational limit in response to the sharing adjustment rate. In addition, when adjustment of the offset power on the power grid side fails, the charging rates of all storage batteries approach the upper or lower operational limit. Furthermore, when the initial SOH of each storage battery is different at the start of operation, even if power is shared equally among the storage batteries, the operating range of the charging rate differs for each storage battery, resulting in variation.

[0008] For this reason, the charging rate of the storage battery is likely to reach the upper or lower operational limit, which may ultimately cause the battery system to stop or shorten the lifespan of the storage battery. In addition, when control is performed to share the power of each storage battery taking into account the deterioration evaluation value of each storage battery (e.g., SOH: State of Health), the variation in the median charging rate between the storage batteries becomes larger.

[0009] The present disclosure has been made in consideration of the above circumstances, and aims to provide a battery control system that can suppress variation in the charging rate of each storage battery and extend the life of the storage batteries and the battery system, a power supply and demand system equipped with the same, a battery control method, and a battery control program. [Means for solving the problem]

[0010] A battery control system according to some embodiments of the present disclosure is a battery control system applied to a battery system having a plurality of storage batteries, and includes an overall average calculation unit that calculates an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period of time, an individual average calculation unit that calculates an individual average charging rate for each storage battery using charging rate data for each storage battery over a predetermined period of time, an offset calculation unit that calculates an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate, and a power command setting unit that sets an individual power command for each storage battery using the individual offset power for each storage battery.

[0011] A battery control system according to some embodiments of the present disclosure is a battery control system applied to a battery system having a plurality of storage batteries, and includes a charging rate determination unit that determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period of time, an offset calculation unit that calculates individual offset power to bring closer to zero the difference between the upper limit of a range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and the difference between the lower limit of a range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate, and a power command setting unit that sets individual power commands for each of the storage batteries using the individual offset power for each of the storage batteries.

[0012] A battery control method according to some embodiments of the present disclosure is a battery control method applied to a battery system including a plurality of storage batteries, and includes the steps of: calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for a predetermined period of the plurality of storage batteries; calculating an individual average charging rate for each storage battery using charging rate data for each storage battery for a predetermined period of time; calculating an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate; and setting an individual power command for each storage battery using the individual offset power for each storage battery.

[0013] A battery control method according to some embodiments of the present disclosure is a battery control method applied to a battery system including a plurality of storage batteries, and includes the steps of: determining an upper representative charging rate and a lower representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; calculating individual offset powers for bringing closer to zero the difference between the upper representative charging rate and an allowable upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally, and the difference between the upper representative charging rate and an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally; and setting individual power commands for each of the storage batteries using the individual offset powers for each of the storage batteries.

[0014] A battery control program according to some embodiments of the present disclosure is a battery control program applied to a battery system including a plurality of storage batteries, and causes a computer to execute the following processes: calculating an overall average charging rate that serves as a benchmark for the entire battery system using charging rate data for the plurality of storage batteries over a predetermined period; calculating an individual average charging rate for each storage battery using charging rate data for each storage battery over a predetermined period; calculating an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate; and setting an individual power command for each storage battery using the individual offset power for each storage battery.

[0015] A battery control program according to some embodiments of the present disclosure is a battery control program applied to a battery system having a plurality of storage batteries, and causes a computer to execute the following processes: a process of determining an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a specified period; a process of calculating individual offset power for bringing closer to zero the difference between the upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and the difference between the lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate; and a process of setting individual power commands for each of the storage batteries using the individual offset power for each of the storage batteries. Effect of the Invention

[0016] According to the present disclosure, it is possible to suppress the variation in the charging rate of each storage battery, and to extend the life of the storage batteries and the battery system. [Brief description of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating a schematic configuration of an electricity supply and demand system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of a battery control system. [Diagram 3] FIG. 2 is a functional configuration diagram showing an example of functions of the battery control system according to the embodiment. [Figure 4] FIG. 1 is an example of an open circuit diagram used for observing charge and discharge currents. [Diagram 5] 10 is a functional configuration diagram showing an example of functions included in an individual offset power setting unit. FIG. [Figure 6] FIG. 13 is a diagram showing an example of a sharing adjustment rate of a storage battery. [Figure 7] FIG. 6 is a diagram showing examples of individual power commands when the sharing adjustment rate is set to 0.8 and 1.2 for comparison. [Figure 8] FIG. 9 is a diagram showing, for comparison, examples of charge and discharge currents when the sharing adjustment ratios are set to 0.8 and 1.2, respectively. [Figure 9] FIG. 9 is a diagram for explaining how the central value of the charging rate varies over time among the storage batteries when the sharing adjustment rate is set to 0.8 and 1.2, respectively. [Figure 10] FIG. 9 is a diagram for explaining how the variation in the central value of the charging rate among the storage batteries over time is suppressed by the individual offset control when the sharing adjustment rates are set to 0.8 and 1.2, respectively. [Figure 11] 13 shows a functional configuration diagram of an individual offset power setting unit according to a first modified example of the first embodiment. FIG. [Figure 12]FIG. 11 is a diagram showing a schematic configuration of an electricity supply and demand system according to a second embodiment of the present disclosure. [Figure 13] FIG. 1 is a schematic diagram conceptually showing individual offset control when a battery system is connected to a DC link. [Figure 14] 13 is an example of a graph showing a relationship between a power command and a voltage expressed by a linear equation when the battery system is connected to a DC link. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of a battery control system, a power supply and demand system including the battery control system, a battery control method, and a battery control program according to the present disclosure will be described with reference to the drawings. 1 is a diagram showing a schematic configuration of an electric power supply and demand system 100 according to an embodiment of the present disclosure. As shown in FIG 1, the electric power supply and demand system 100 includes a battery system (ESS: Energy Storage System) 1 and a battery control system 10.

[0019] The battery system 1 is connected to a power grid 2 via a substation 3, and supplies and demands electric power to and from the power grid 2. The substation 3 and the battery system 1 are connected by an AC link 4. The battery system 1 includes a plurality of storage batteries 5 (5a to 5d). FIG. 1 illustrates an example in which four storage batteries 5 are included, but the number of storage batteries 5 is not limited. Hereinafter, when it is necessary to distinguish between the storage batteries 5a, 5b, etc., they will be referred to as storage batteries 5a, 5b, and when it is not necessary to distinguish between them, they will be simply referred to as storage batteries 5. Other configurations will be treated in the same manner.

[0020] Each storage battery 5 is capable of charging and discharging, and is configured, for example, as a battery string in which a plurality of unit batteries (cells) are connected in series. Alternatively, a configuration in which a plurality of battery strings are connected in parallel may be used. Also, each storage battery 5 may include a measurement unit (not shown) that measures various data (battery information) such as voltage value, current value, and temperature, and a battery management unit (BMU: Battery Management Unit) (not shown) that monitors the state of the storage battery 5 based on the measurement data. Note that the configuration of the storage battery 5 may be any known technology as appropriate, and is not particularly limited.

[0021] Each storage battery 5 is connected to the AC link 4 via a power converter 7 (7a to 7d). The power converter 7 is, for example, an AC / DC converter. The power converter 7 controls the charging and discharging of the storage battery 5 by, for example, being driven based on an individual power command given from the battery control system 10. Specifically, the power converter 7a controls the charging and discharging of the storage battery 5a, the power converter 7b controls the charging and discharging of the storage battery 5b, the power converter 7c controls the charging and discharging of the storage battery 5c, and the power converter 7d controls the charging and discharging of the storage battery 5d. During charging, the power converter 7 converts AC power from the power system into DC power and outputs it to the storage battery 5, and during discharging, the power converter 7 converts DC power from the storage battery 5 into AC power and supplies it to the power system 2.

[0022] The battery control system 10 is a control system that controls the battery system 1. The battery control system 10 is connected to the battery system 1 via, for example, a communication network, and is configured to be able to send and receive information. The battery control system 10 may be a cloud server, or may be a local system installed at the location where the battery system 1 is installed. The battery control system 10 is also connected to a grid monitoring system 6 via a communication network. The grid monitoring system 6 is, for example, a central power supply command center of a power company or a higher-level energy management system (EMS), and determines the system required power to be requested of the battery system 1 and transmits it to the battery control system 10.

[0023] Next, the battery control system 10 according to this embodiment will be described. Fig. 2 is a diagram showing an example of a hardware configuration of the battery control system 10. As shown in Fig. 2, the battery control system 10 is a computer and includes, for example, a CPU (Central Processing Unit: processor) 11, a main memory 12, a secondary storage 13, a communication interface 14, and the like. The battery control system 10 may also include an input device 15 that accepts input from a user, a display 16, and the like. These components are connected to each other via, for example, a bus 18.

[0024] The main memory device 12 is composed of writable memory such as a cache memory or a RAM (Random Access Memory), and is used as a working area for reading out the execution program of the CPU 11, writing processing data by the execution program, and the like. The secondary storage device 13 is a non-transitory computer readable storage medium. Examples of the secondary storage device 13 include a magnetic disk such as a hard disk drive (HDD), a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory such as a solid state drive (SSD), and the like.

[0025] Fig. 3 is a functional configuration diagram showing an example of functions of the battery control system 10 according to this embodiment. With the battery system 1 connected to the power grid 2, the battery control system 10 evaluates the degradation state of each storage battery 5, and controls charging and discharging of each storage battery 5 using the evaluation result of the degradation state. Specifically, as shown in Fig. 3, the battery control system 10 includes a degradation state evaluation unit 20, a data management unit 30, a sharing adjustment rate setting unit 40, a power command setting unit 50, a storage unit 60, and an individual offset power setting unit 70.

[0026] A series of processes for realizing various functions described below is stored in the secondary storage device 13 (see FIG. 2) in the form of a program (e.g., a battery control program), for example, and the CPU 11 reads this program into the main storage device 12 and executes information processing and arithmetic processing to realize various functions. Note that the program may be pre-installed in the secondary storage device 13, provided in a state stored in another computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0027] The degradation state evaluation unit 20 performs degradation state evaluation to evaluate the degradation state of the storage battery 5. The degradation state evaluation is performed in a state where the storage battery 5 is connected to the power grid 2. The degradation state evaluation is started when a preset start condition is satisfied. Examples of the start condition include when a predetermined period has passed since the previous degradation state evaluation, when the cumulative operating time since the previous degradation state evaluation reaches a predetermined time, when a command to start the degradation state evaluation is input by a user, and the like. The start condition may be set as a combination of these. Also, the cycle of the degradation state evaluation may be set to be shorter as the degradation evaluation value decreases.

[0028] The data management unit 30 (see FIG. 3 ), for example, stores the degradation assessment information acquired from the degradation state assessment unit 20 in the storage unit 60. The data management unit 30 also stores in the storage unit 60 the sharing adjustment rates of the storage batteries 5a to 5d calculated by the sharing adjustment rate setting unit 40, which will be described later, and the like.

[0029] The sharing adjustment rate setting unit 40 sets a sharing adjustment rate for each of the storage batteries 5a-5d based on the deterioration evaluation value (SOH) of each of the storage batteries 5a-5d stored in the memory unit 60. For example, the sharing adjustment rate setting unit 40 calculates a target deterioration evaluation value using the deterioration evaluation values ​​of the storage batteries 5a-5d constituting the battery system 1, and sets a sharing adjustment rate for each storage battery that brings the deterioration evaluation value of each of the storage batteries 5a-5d closer to the target deterioration evaluation value. The target deterioration evaluation value is, for example, an average value of the deterioration evaluation values ​​of the storage batteries 5a-5d.

[0030] As a result, a larger sharing adjustment rate is set for a storage battery with a high degradation evaluation value (e.g., a high SOH) than for a storage battery with a low degradation evaluation value. A storage battery 5 with a high sharing adjustment rate is assigned a larger portion of the required power relative to the system required power than a storage battery 5 with a low sharing adjustment rate. That is, when charging, a storage battery with a high sharing adjustment rate charges more power than a storage battery with a low sharing adjustment rate, and when discharging, a storage battery with a high sharing adjustment rate discharges more power than a storage battery with a low sharing adjustment rate.

[0031] For example, the sharing adjustment rate setting unit 40 calculates the sharing adjustment rate α(i) using a target deterioration evaluation value SOHave, which is the average value of the SOH of the storage batteries 5a to 5d, and each deviation ΔSOH(i) between the target deterioration evaluation value SOHave and the SOH(i) of each storage battery 5. As an example, the sharing adjustment rate α(i) is calculated by the following formula (1).

[0032] Sharing adjustment rate α(i)={1+K(ΔSOH(i) / SOHave)} (1)

[0033] In the above formula (1), i indicates identification information of the storage batteries 5a to 5d (for example, i=1 to 4), and for example, the sharing adjustment rate α(1) of the storage battery 5a is expressed by the following formula.

[0034] Sharing adjustment rate α(1)={1+K(ΔSOH(1) / SOHave)}

[0035] In the above formula (1), K is an adjustment gain, and the larger this adjustment gain K is, the shorter the time it takes for the variation in the degradation evaluation value to fall within a predetermined range. The adjustment gain K is a value equal to or greater than zero, and its upper limit is set within a range in which the sum of the individual power commands allocated to the operational storage batteries does not exceed the system required power. When the adjustment gain K is set to zero, the sharing adjustment rates of the storage batteries 5a to 5d are all 1, and in this case, there is no increase or decrease in the power sharing according to SOH(i). In other words, the system required power is allocated equally to each storage battery.

[0036] For example, when a preset calculation start condition is satisfied, the sharing adjustment rate setting unit 40 calculates the sharing adjustment rate α(i) and updates each sharing adjustment rate α(i) in the storage unit 60. Here, the predetermined calculation start condition may be, for example, when the degradation state evaluation unit 20 performs a degradation state evaluation to calculate degradation evaluation values ​​for all the storage batteries 5a-5d, and degradation evaluation information including the degradation evaluation values ​​of the storage batteries 5a-5d is stored in the storage unit 60. Furthermore, the sharing adjustment rate setting unit 40 may update the sharing adjustment rate α(i) when the operation mode of the battery system 1 changes, for example, when a storage battery is suspended.

[0037] After calculating the sharing adjustment rate for each storage battery, the sharing adjustment rate setting unit 40 outputs sharing adjustment rate information that associates the identification information of each storage battery with the sharing adjustment rate to the data management unit 30 (see FIG. 3). The sharing adjustment rate information may include time information and the like.

[0038] The power command setting unit 50 calculates an individual power command Pdiv(i) for each operational battery using the sharing adjustment rate α(i) corresponding to each battery and the system required power Pall acquired from the grid monitoring system 6. Here, the operational battery is an operational battery, in other words, a battery capable of being controlled for charging and discharging in response to the system required power Pall. That is, the battery for which degradation is evaluated by the above-mentioned degradation state evaluation unit 20 is excluded from the operational batteries.

[0039] The power command setting unit 50 acquires the sharing adjustment rate α(i) of each operational storage battery stored in the memory unit 60, and calculates individual power commands for each operational storage battery by using the acquired sharing adjustment rate α(i) and the system required power Pall in the following equation (2).

[0040] Pdiv(i)=Pall×(1 / N)×α(i) (2)

[0041] In the above formula (2), N indicates the number of operational batteries. For example, when the degradation state evaluation unit 20 described above has not performed a degradation state evaluation, the batteries 5a to 5d can be operational batteries, and during a period when a degradation state evaluation is being performed, a battery other than the evaluation target can be an operational battery.

[0042] As can be seen from formula (2), a larger individual power command is set for an operational storage battery with a high degradation evaluation value (high health) than for an operational storage battery with a low degradation evaluation value. After allocating an individual power command Pdiv(i) to each operational storage battery, the power command setting unit 50 transmits the individual power command Pdiv(i) to the power conversion device 7 corresponding to each operational storage battery. As a result, charging and discharging control according to the individual power command Pdiv is performed in each operational storage battery.

[0043] In a battery system in which multiple storage batteries are connected, the deterioration evaluation value (SOH: State of health) may differ for each storage battery. Therefore, in order to use each storage battery for a long period of time, as described above, sharing control is performed to share the load of each storage battery according to the deterioration evaluation value of each storage battery. However, by performing sharing control, differences are created in the load of each storage battery, which causes variations (imbalance) in the charging and discharging of each storage battery.

[0044] In addition, it was found that when power sharing is controlled to change according to the deterioration evaluation value of the storage battery 5, the central value of the state of charge (SOC) varies over time between the storage batteries. For example, a storage battery with a relatively large sharing adjustment rate, for example, a storage battery with a sharing adjustment rate of 1 or more, tends to have a large discharge current and a small charge current, while a storage battery with a relatively small sharing adjustment rate, for example, a storage battery with a sharing adjustment rate of less than 1, tends to have a small discharge current and a large charge current. Even when power sharing based on the deterioration evaluation value is not performed, the central value of the state of charge between the storage batteries varies to a certain extent due to individual differences in the storage batteries.

[0045] For this reason, the inventors have studied measures to address the problem of variation among the storage batteries caused by changing the charge / discharge current of each storage battery by changing the sharing adjustment rate of each storage battery in this way.

[0046] The inventors observed how the charge / discharge current changes depending on the state of the individual power command change amount ΔP(i) depending on whether sharing control is executed or not. Figure 4 is an example of an open circuit diagram used to observe the charge / discharge current. As for the observation condition, in the open circuit of Figure 4, there is one column, and the open circuit voltage OCV (OCV: Open Circuit Voltage) and direct current resistance DCR (DCR: Direct Current Resistance) of the cells in the column have the same characteristics.

[0047] In this case, the individual power command change amount ΔP(i) is the difference between the individual power command P0(i) when sharing control is not performed and the individual power command Pdiv(i) when sharing control is performed, as expressed by the following formula.

[0048] ΔP(i)=Pdiv(i)-P0(i) (3)

[0049] In addition, when sharing control is not performed, offset adjustment is applied to all storage batteries to make the charging current and discharging current equal. Under these conditions, the current I flowing through the open circuit in Figure 4 is expressed by the following formula.

[0050]

number

[0051] In addition, the amount of change in current ΔI(i) due to whether or not sharing control is performed is the difference between the current I0(i) when sharing control is not performed and the current Idiv(i) when sharing control is performed, and is expressed by the following equation (5) based on equations (3) and (4).

[0052]

number

[0053] In equation (5), since the open circuit voltage OCV and the DC resistance DCR have the same characteristics, the current change amount ΔI(i) changes according to the individual power command change amount ΔP(i) depending on whether or not sharing control is performed. For this reason, when the individual power command change amount ΔP(i)>0 during discharge (positive side) of the storage battery 5 (when the sharing adjustment rate is increased), for example, when ΔP(i)=(+45kW)-(+30kW)=(+15kW)>0, the current change amount ΔI(i)>0 and the current I increases. That is, when the individual power command change amount ΔP(i)>0 during discharge, the discharge current increases. Also, when the individual power command change amount ΔP(i)<0 during discharge (positive side) of the storage battery 5 (when the sharing adjustment rate is decreased), for example, when ΔP(i)=(-15kW)-(-30kW)=(+15kW)>0, the current change amount ΔI(i)>0 and the current I decreases. That is, when the individual power command change amount ΔP(i)<0 during discharge, the discharge current decreases.

[0054] Furthermore, when the individual power command change amount ΔP(i)>0 when the storage battery 5 is being charged (negative side) (when the sharing adjustment rate is reduced), for example, when ΔP(i)=(+45kW)-(+30kW)=(+15kW)>0, the current change amount ΔI(i)>0 and the current I increases. That is, when the individual power command change amount ΔP(i)>0 when charging, the charging current increases. Furthermore, when the individual power command change amount ΔP(i)<0 when the storage battery 5 is being charged (negative side) (when the sharing adjustment rate is increased), for example, when ΔP(i)=(-45kW)-(-30kW)=(-15kW)<0, the current change amount ΔI(i)>0 and the current I decreases. That is, when the individual power command change amount ΔP(i)<0 when charging, the charging current decreases.

[0055] From the above, when the sharing adjustment rate corresponding to a given storage battery 5 is increased, the discharge current of the storage battery increases and the charge current decreases. In other words, the charging rate of the storage battery changes to approach 0%. Conversely, when the sharing adjustment rate corresponding to a given storage battery is decreased, the discharge current of the storage battery decreases and the charge current increases. In other words, the charging rate of the storage battery changes to approach 100%.

[0056] In this way, when different sharing adjustment rates are set for each storage battery, variation occurs in the charge / discharge current of each storage battery, and the change tendency of the charging rate of each storage battery also varies. In order to suppress such variation in the change tendency of the charging rate of each storage battery, the inventors have considered a control that gives an offset amount individually to each power command for adjusting the charging rate of each storage battery (hereinafter referred to as "individual offset control").

[0057] The battery control system 10 includes an individual offset power setting unit 70 as a component for executing individual offset control. The individual offset power setting unit 70 also includes an individual average calculation unit 71, a total average calculation unit 72, and an offset calculation unit 73. Fig. 5 is a functional configuration diagram showing an example of functions included in the individual offset power setting unit 70.

[0058] The individual average calculation unit 71 calculates an individual average charging rate for each storage battery using charging rate data (SOC data) for each storage battery 5 for a predetermined period. For example, battery information (current data, voltage data, temperature data, abnormality detection data, etc.) for each storage battery 5a-5d is repeatedly transmitted from the battery system 1 to the battery control system 10 at predetermined time intervals. The individual average calculation unit 71 calculates the individual average charging rate by performing a smoothing process on the charging rate data for each storage battery for the predetermined period.

[0059] An example of the smoothing process is a moving average. In the present embodiment, the case where the individual average charging rate is calculated by the moving average process is described as an example, but the present invention is not limited to this example. For example, the individual average calculation unit 71 may specify the maximum charging rate and the minimum charging rate in a predetermined period for each storage battery, and calculate the average value of the specified maximum charging rate and minimum charging rate as the individual average charging rate. In addition, the present invention is not limited to the above method, and it is possible to appropriately use a statistical method for calculating an approximate central value of the charging rate in a predetermined period.

[0060] The overall average calculation unit 72 uses the charging rate data of the multiple storage batteries 5a to 5d for a predetermined period to calculate an overall average charging rate that serves as a reference for the entire battery system 1. For example, the overall average calculation unit 72 may calculate the average value of the individual average charging rates of the storage batteries calculated by the individual average calculation unit 71 as the overall average charging rate. Alternatively, the maximum charging rate and the minimum charging rate for the entire battery system 1 for the predetermined period may be identified, and the average value of these values ​​may be calculated as the overall average charging rate. As for the overall average charging rate, the charging rate data of each storage battery for the predetermined period may be statistically processed to calculate the median value of the charging rates, and a known technique may be appropriately adopted as a specific method.

[0061] The above-mentioned predetermined period can be set appropriately depending on the operation of the battery system 1. For example, a simulation can be performed in advance, and a period during which the central value of the charging rate varies across the entire battery system can be set as the predetermined period.

[0062] The offset calculation unit 73 calculates an individual offset power for each storage battery 5 to bring the individual average charging rate of each storage battery 5 closer to the overall average charging rate. For example, in the case of the storage battery 5a, the deviation between the individual average charging rate of the storage battery 5a and the overall average charging rate is calculated, and an individual offset power is calculated to make the deviation zero by performing proportional-integral control on the deviation. Similarly, an individual offset power is calculated for each of the storage batteries 5b to 5d.

[0063] After calculating the individual offset power for each of the storage batteries 5a to 5d, the offset calculation unit 73 outputs individual offset information that associates the identification information of each storage battery with the individual offset power to the data management unit 30. As a result, the individual offset information is stored in the storage unit 60, and the individual offset information is updated at predetermined intervals.

[0064] Further, the offset calculation unit 73 may use a target average charging rate that is a fixed value instead of the overall average charging rate to calculate an individual offset power for each storage battery 5 to bring the individual average charging rate closer to the target average charging rate. The target average charging rate may be stored in the storage unit 60 in advance.

[0065] The offset calculation unit 73 may calculate an individual offset power for bringing each individual average charging rate of each storage battery closer to the overall average charging rate so that the charging rate of each storage battery falls within the range of the allowable upper limit and lower limit of the range of the charging rate in which the storage battery can be normally operated. The allowable upper limit and lower limit of the range of the charging rate in which the storage battery can be normally operated may be stored in advance in the storage unit 60.

[0066] For example, when the condition is that the value is within the range of the allowable upper and lower limits of the range of charging rates at which each storage battery can be operated normally, the offset calculation unit 73 calculates, for each storage battery, an individual offset power for bringing closer to zero the difference between the allowable upper limit of the charging rate at which the storage battery stored in the memory unit 60 can be operated normally and the maximum moving average charging rate, and the difference between the allowable lower limit of the charging rate at which the storage battery stored in the memory unit 60 can be operated normally and the minimum moving average charging rate. The method of calculating the individual offset power will be described later.

[0067] In addition, when the battery system 1 is a system that uses DC power such as a DC link, the offset calculation unit 73 may use the calculated individual offset power to calculate the intercept of a linear equation for calculating the DC charging and discharging power. More specifically, the offset calculation unit 73 calculates the intercept of the linear equation of the power-voltage characteristics of the storage battery 5 from the individual offset power in response to the operating mode of the battery energy storage system (BESS: Battery Energy Storage System) of the battery control system, the charging rate of the storage battery 5, and the proportionality coefficient of the linear equation of the power-voltage characteristics of the storage battery 5.

[0068] The power command setting unit 50 acquires the individual offset information and sharing adjustment rate information stored in the storage unit 60, and sets the individual power command Pdiv'(i) of the operating storage battery using the acquired individual offset power (Ps(i)) and sharing adjustment rate α(i) for each storage battery. For example, the individual power command Pdiv'(i) is given by the following formula (6).

[0069] Pdiv'(i)={Pall×(1 / N)×α(i)}+Ps(i) (6)

[0070] As a result, an individual power command is given to each operational storage battery based on the deterioration evaluation value and that suppresses variation in the charging rate between the storage batteries over time, and charging and discharging control of the power conversion device 7 is performed based on this individual power command.

[0071] (Method 1 for calculating individual offset power) An example of individual offset control, including a method of calculating individual offset power, will be described below. When controlling multiple storage batteries 5, if the sharing adjustment rate is changed according to the deterioration evaluation value of each storage battery, the specifications of the battery system, the operation pattern, etc., the central charging rate of each storage battery will shift according to the sharing adjustment rate. Therefore, in order to align the charging rate of each storage battery to the average charging rate, individual offset control is implemented in which an individual power command corresponding to the state of each storage battery 5 is added to each storage battery 5.

[0072] First, the individual average calculation unit 71 calculates the moving average state of charge SOC(i), which is the moving average of the state of charge SOC(i) of the storage battery that is the degradation suppression target, using the following formula (7). MA (i) are calculated respectively. In the following formula, N MA is the number of samples.

[0073]

number

[0074] Next, the overall average calculation unit 72 calculates the moving average state of charge SOC MA (i) is used to calculate the moving average SOC MA (i) is the average of the overall average state of charge SOC MAAVG is calculated using the following formula (8), where N is the number of operating batteries.

[0075]

number

[0076] Furthermore, the offset calculation unit 73 calculates the moving average state of charge SOC of each storage battery from the difference between the calculation results of equations (7) and (8). MA (i) and overall average charge rate SOC MAAVGUsing the difference between these, the individual offset power Ps(i) is calculated using the following formula (9). In the following formula, KP2 is a proportional gain. Regarding the method of setting the proportional gain KP2, a known method can be appropriately used depending on the specifications of the battery system, the specifications of the storage battery, etc.

[0077]

number

[0078] In this way, the offset calculation unit 73 calculates the moving average SOC(i) of the SOC(i) for each battery storage location. MA (i) and overall average charge rate SOC MAAVG Then, the power command setting unit 50 adds the individual offset information including each individual offset power Ps(i) to the power command of each storage battery 5, and controls the power of each storage battery 5 so as to stabilize the charging rate of each storage battery 5.

[0079] In addition, in formula (9), when a stopped storage battery 5 is restored, the target overall average charging rate SOC MAAVG In such a case, the overall average state of charge SOC MAAVG Instead, a predetermined fixed target average charge rate SOC TRG may be used.

[0080]

number

[0081] In equation (10), the target average charging rate SOC TRG is a fixed value, the individual offset power Ps(i) is not affected when the storage battery 5 is restored or disconnected. In addition, the following equation (11) can be derived based on equation (10).

[0082]

number

[0083] As shown in equation (11), the overall average state of charge SOC MAAVG Instead, a predetermined fixed target average charge rate SOC TRG By using the above formula, the sum of the individual offset powers Ps(i) coincides with the total offset power, so that the logic can be simplified.

[0084] Next, the verification result of the effect of individual offset control in a battery system in which load sharing control is executed on a storage battery will be described with reference to Figs. 6 to 10. Figs. 6 to 10 are diagrams comparing a storage battery with a relatively high SOH and a storage battery with a relatively low SOH in a battery system in which load sharing control is executed. In Figs. 6 to 10, the solid line corresponds to a storage battery with a relatively low SOH (e.g., storage battery 5a), and the dashed line corresponds to a storage battery with a relatively high SOH (e.g., storage battery 5b). Fig. 6 is a diagram showing an example of a sharing adjustment rate of a storage battery. Fig. 7 is a diagram showing an example of an individual power command when the sharing adjustment rate is set to 0.8 and 1.2, respectively, for comparison, as shown in Fig. 6. Fig. 8 is a diagram showing an example of a charge / discharge current when the sharing adjustment rate is set to 0.8 and 1.2, respectively, for comparison, as shown in Fig. 6. Fig. 9 is a diagram for explaining that the central value of the charging rate varies over time among the storage batteries when the sharing adjustment rates are set to 0.8 and 1.2, respectively, as shown in Fig. 6. Fig. 10 is a diagram for explaining that the variation occurring in the central value of the charging rate among the storage batteries over time is suppressed by individual offset control when the sharing adjustment rates are set to 0.8 and 1.2, respectively, as shown in Fig. 6.

[0085] As shown in Figs. 6 to 8, when sharing control is performed, the sharing adjustment rate of the storage battery with a relatively high SOH is increased, and the sharing adjustment rate of the storage battery with a relatively low SOH is decreased. As a result, the maximum value of the power of the storage battery with a relatively high SOH is greater than the maximum value of the power of the storage battery with a relatively low SOH. Also, the minimum value of the power of the storage battery with a relatively high SOH is smaller than the minimum value of the power of the storage battery with a relatively low SOH. The same applies to the current of the storage batteries. In this way, if the sharing adjustment rate is set differently for each battery depending on the SOH, as shown in Figure 9, the charging rates of both the batteries with relatively high SOH and the batteries with relatively low SOH will change from the initial central charging rate.

[0086] 9 and 10 show the transition of the charging rate of each storage battery. As shown in FIG. 9, when the individual offset control is not performed, the charging rate of a storage battery with a relatively low SOH (for example, the storage battery 5a) shows an upward trend, and the charging rate of a storage battery with a relatively high SOH (for example, the storage battery 5b) shows a downward trend. Here, since the range of charging rates at which the storage batteries can be operated normally is predetermined, if the storage batteries are continued to be used without performing the individual offset control on the storage batteries, the charging rate of a storage battery with a relatively high SOH is likely to reach the allowable lower limit of the charging rate at which the storage batteries can be operated normally, and the charging rate of a storage battery with a relatively low SOH is likely to reach the allowable upper limit of the charging rate at which the storage batteries can be operated normally. When the charging rate of a storage battery is close to the allowable upper limit or the allowable lower limit of the range at which the storage batteries can be operated normally, there is an increased possibility that the charging rate of the storage battery reaches the allowable upper limit or the allowable lower limit, causing the battery system 1 to stop, or shortening the life of the storage battery.

[0087] Next, as shown in Fig. 10, when the individual offset control is performed, neither the charging rate of the storage battery with a relatively high SOH (e.g., storage battery 5b) nor the charging rate of the storage battery with a relatively low SOH (e.g., storage battery 5a) shows an increasing or decreasing tendency. In other words, by performing the individual offset control, it is possible to suppress the increase or decrease in the charging rate of each storage battery when the storage batteries are operated over a long period of time, and to stabilize the operating state of the storage batteries. This makes it possible to suppress the charging rate of each storage battery from reaching the allowable upper or lower limit of the range in which normal operation is possible, thereby suppressing the possibility of the system stopping or the possibility of shortening the life of the storage batteries.

[0088] As described above, by performing individual offset control in a battery control system that controls each storage battery, the variation in the charging rate of each storage battery can be suppressed, and as a result, the lifespan of the storage batteries and the battery system can be extended. In addition, since the variation in the charging rate of each storage battery can be suppressed, it is possible to prevent only a specific storage battery from deteriorating and reaching the allowable upper or lower limit of the charging rate at which the battery system can operate normally. This makes it possible to prevent the entire system from stopping. In addition, by calculating a moving average of the charging rates of the storage batteries to calculate the individual average charging rate, it is possible to accurately grasp the tendency of the charging rate change even in an operation pattern in which the charging rate changes instantaneously.

[0089] (Method 2 for calculating individual offset power) In the above-mentioned calculation method, an example in which a moving average is used to calculate the individual average charging rate of the storage battery is described, but other calculation methods may be used. Below, a method for calculating the individual average charging rate and the overall average charging rate using the maximum charging rate and the minimum charging rate of each storage battery in a predetermined period will be described. For example, the individual average calculation unit 71 may specify the maximum charging rate and the minimum charging rate for each storage battery in a predetermined period, and calculate the individual average charging rate using the specified maximum charging rate and minimum charging rate. In this case, the central charging rate, which is the average of the maximum charging rate and the minimum charging rate for each storage battery, is calculated by the individual average calculation unit, and the calculated central charging rate corresponds to the individual average charging rate.

[0090] Moreover, the overall average calculation unit 72 calculates an average of the central charging rates using the central charging rates for each storage battery calculated by the individual average calculation unit 71, and sets the calculation result as the overall average charging rate. In this case, the average of the central charging rates calculated for each storage battery may be calculated, and the calculation result may correspond to the overall average charging rate. Note that the overall average calculation unit 72 may specify the maximum charging rate and the minimum charging rate for each storage battery in a predetermined period, and calculate the overall average charging rate using the specified maximum charging rate and minimum charging rate.

[0091] As described above, by specifying the maximum charging rate and the minimum charging rate and calculating the individual average charging rate and the overall average charging rate instead of calculating the moving average of the charging rates of the storage batteries, it is possible to calculate the overall average charging rate with less memory capacity than when calculating the moving average. In other words, it is possible to reduce the calculation cost of the individual average charging rate and the overall average charging rate. Furthermore, since the calculation cost is reduced compared to when calculating the moving average of the charging rates of the storage batteries, it is possible to quickly respond to changes in the charging rates of the storage batteries.

[0092] (Individual offset power calculation method 3) A method of calculating an individual average charging rate and an overall average charging rate using the maximum moving average charging rate and the minimum moving average charging rate among the moving average charging rates of the storage batteries in a predetermined period will be described below. For example, the individual average calculation unit 71 may calculate a moving average charging rate that is a moving average of the charging rates of each storage battery in a predetermined period, and may specify a maximum moving average charging rate that is the maximum value of the moving average charging rates and a minimum moving average charging rate that is the minimum value of the moving average charging rates for each storage battery, and calculate an individual average charging rate using the specified maximum moving average charging rate and minimum moving average charging rate. In this case, a central moving average charging rate that is the average of the maximum moving average charging rate and the minimum moving average charging rate for each storage battery is calculated by the individual average calculation unit 71, and the calculated central moving average charging rate corresponds to the individual average charging rate.

[0093] The overall average calculation unit 72 may also specify the maximum moving average charging rate and the minimum moving average charging rate for each storage battery in a predetermined period, and calculate the overall average charging rate using the specified maximum moving average charging rate and minimum moving average charging rate. In this case, the average of the center moving average charging rates calculated for each storage battery may be calculated, and the calculation result may be the overall average charging rate. Note that the overall average calculation unit 72 may also calculate the average of the center moving average charging rates for each storage battery using the center moving average charging rate calculated by the individual average calculation unit 71, and the calculation result may be the overall average charging rate.

[0094] As described above, by calculating the individual average charging rate and the overall average charging rate using the maximum moving average charging rate and the minimum moving average charging rate, it is possible to accurately grasp the trend of changes in the charging rate even for driving patterns in which the charging rate changes instantaneously, while suppressing calculation costs.

[0095] (Individual offset power calculation method 4) A method for calculating an overall average charging rate using the maximum charging rate and the minimum charging rate for each storage battery in a predetermined period will be described below. For example, the overall average calculation unit 72 may specify the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates using the maximum charging rate and the minimum charging rate for each storage battery in a predetermined period specified by the individual average calculation unit 71, and may calculate the overall average charging rate using the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates. In this case, the average of the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates may be calculated, and the calculation result may be set as the overall average charging rate.

[0096] As described above, the overall average calculation unit 72 calculates the overall average charging rate using the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates, so that the overall average charging rate can be calculated with less memory capacity. That is, the calculation cost of the individual average charging rate and the overall average charging rate can be reduced. Furthermore, since the calculation cost is reduced compared to the case of calculating a moving average of the charging rate for each storage battery, it is possible to quickly respond to changes in the charging rate of the storage battery.

[0097] (Variation 1) In the above-mentioned method, the individual offset power is calculated using the overall average charging rate of the storage batteries using the charging rate data for each storage battery, but this is not limited to this. In this example, a method for setting the individual offset power for operating the battery system 1 in consideration of the range in which the charging rate of each storage battery can be normally operated will be described. FIG. 11 shows a functional configuration diagram of an individual offset power setting unit 70a according to this example. As shown in FIG. 11, the individual offset power setting unit 70a includes a charging rate determination unit 74 and an offset calculation unit 75.

[0098] The charging rate determination unit 74 determines the upper limit representative charging rate and the lower limit representative charging rate of the battery system 1 by using the charging rate data of the battery system 1 during a predetermined period. The upper limit representative charging rate is a representative value treated as the maximum value of the charging rate for each storage battery, and similarly, the lower limit representative charging rate is a representative value treated as the minimum value of the charging rate for each storage battery. In this example, for example, the maximum moving average charging rate is determined as the upper limit representative charging rate, and the minimum moving average is determined as the lower limit representative charging rate. The method of determining the maximum moving average and the minimum moving average may be such that the maximum value of the averages of the charging rates in each section obtained by dividing the predetermined period into a plurality of sections is determined as the maximum moving average, and the minimum value of the calculated moving averages is determined as the minimum moving average. In this way, by using the moving average, it is possible to have the same function as a filter such as a noise removal filter. In addition, a first-order lag filter may be used in consideration of the limit of the data capacity required for the moving average.

[0099] Without being limited to this example, the maximum charging rate of the battery system 1 may be determined as the upper limit representative charging rate, and the minimum charging rate of the battery system 1 may be determined as the lower limit representative charging rate. The upper limit representative charging rate and the lower limit representative charging rate are not limited to this. For example, the average value of the maximum charging rates of the storage batteries 5a-5d may be set as the upper limit representative charging rate, and the average value of the minimum charging rates of the storage batteries 5a-5d may be set as the lower limit representative charging rate. Furthermore, the upper limit representative charging rate and the lower limit representative charging rate may be determined using statistical processing such as moving average.

[0100] The offset calculation unit 75 calculates the difference between the maximum moving average charging rate and the allowable upper limit of the charging rate (upper limit difference) and the difference between the minimum moving average charging rate and the allowable lower limit of the charging rate (lower limit difference), and calculates an individual offset power for bringing the deviation between the upper limit difference and the lower limit difference closer to zero. The offset calculation unit 75 calculates the individual offset power, for example, by performing proportional-integral control on the deviation.

[0101] In this example, the state where the difference between the upper limit difference and the lower limit difference is zero is, in other words, a state where the margin of the maximum moving average charging rate relative to the allowable upper limit value of the charging rate is equal to the margin of the minimum moving average charging rate relative to the allowable lower limit value of the charging rate. According to the individual offset power setting unit 70a of this example, by bringing the difference between the upper limit difference and the lower limit difference closer to zero, it becomes possible to control the operational fluctuation range of the charging rate of the entire battery system at about the center between the allowable upper limit value and the allowable lower limit value. This makes it possible to suppress the center of the operational fluctuation range of the charging rate of the entire battery system from gradually shifting, and to extend the life of the battery system.

[0102] (Second embodiment: when the battery system uses DC power) In the above embodiment, the case where the battery system 1 is connected to the AC link 4 has been described as an example, but the battery system 1 can also be applied to the case where it is connected to the DC link 8. In the power supply and demand system 100 according to the first embodiment described above, the power conversion device 7 is an AC / DC converter, and the case where the battery system 1 is connected to the AC link 4 via this power conversion device 7 has been described as an example. In contrast, in the power supply and demand system 100a according to the present embodiment, as shown in FIG. 12, the battery system 1a is connected to the DC link 8 via a power conversion device 7' (7a' to 7d') which is a DC / DC converter. In addition, the DC link 8 and the substation 3 are connected to each other via an AC / DC converter 9.

[0103] Here, when the battery system is a direct current power system such as a DC link, the offset calculation unit 73 calculates an intercept b(i) in the linear equation of the power command-voltage characteristics from the individual offset power Ps(i) in order to apply the individual offset power Ps(i) calculated by the formula (9) to the linear equation of the power command-voltage characteristics of the storage battery. FIG. 13 is a schematic diagram conceptually showing individual offset control when the battery system 1 is connected to the DC link 8. As shown in FIG. 13, the offset calculation unit 73 calculates an intercept b(i) of the linear equation of the power command-voltage characteristics of the storage battery from the individual offset power Ps(i) in response to the operation mode of the battery energy storage system (BESS: Battery Energy Storage System) of the battery control system, the charging rate SOC(i) of the storage battery, and the proportionality coefficient a(i) of the linear equation of the power command-voltage characteristics of the storage battery.

[0104] A specific calculation procedure is shown below. The linear expression of the power command-voltage characteristic before adding the individual offset power Ps(i) is expressed by the following equation (12). Note that a(i) is a proportionality coefficient.

[0105]

number

[0106] Furthermore, if the amount of change in voltage V when individual offset power Ps(i) is added is taken as intercept b(1), the following equation (13) is given based on the above equation (12).

[0107]

number

[0108] Furthermore, when intercept b1 is calculated using equations (12) and (13), equation (14) is derived.

[0109]

number

[0110] Generalizing equation (10) gives the following equation (15).

[0111]

number

[0112] From the above, when the battery system is a DC power system, the offset calculation unit 73 can calculate the intercept b(i) of the linear expression using the individual offset power Ps(i).

[0113] Fig. 14 is an example of a graph showing the relationship between power command and voltage expressed as a linear equation when the battery system 1 is connected to the DC link 8. In Fig. 14, the horizontal axis shows the power command, and the vertical axis shows the voltage. In a DC battery system, the power command-voltage relationship can be expressed as a linear equation as shown in equations (12) and (13). In Fig. 14, the dashed line corresponds to the linear equation (12), and the dashed line corresponds to the linear equation (13).

[0114] As shown in equations (12) to (15) and the two-dot chain line in Fig. 14, adding the individual offset power Ps(1) to the power command (horizontal axis direction) is equivalent to adding an intercept b1 to the voltage (vertical axis direction). In this way, by further calculating the intercept using the individual offset power Ps(i) and having the power command setting unit set the individual power command for each storage battery using the intercept, when the battery system is a system that uses DC power, it is possible to simply control the power command-voltage and stabilize the control of the battery system.

[0115] Although the present disclosure has been described above using the embodiments, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. Various modifications or improvements can be made to the above embodiments without departing from the gist of the present disclosure, and the forms in which such modifications or improvements are made are also included in the technical scope of the present disclosure. In addition, the above embodiments may be appropriately combined.

[0116] For example, in each of the above-described embodiments and modifications, the battery control system 10 is provided with the storage unit 60, but there is no particular limitation on the location of the storage unit 60. For example, the storage unit 60 may be configured to be accessible by the battery control system 10, and as one example, the storage unit may be configured to be capable of reading and writing data from and to the storage unit via a network.

[0117] (Additional Notes) The battery control system, the power supply and demand system including the battery control system, the battery control method, and the battery control program described in the above-described embodiments can be understood, for example, as follows. A battery control system (10, 10a) according to a first aspect of the present disclosure is a battery control system applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes an overall average calculation unit (72) that calculates an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period of time, an individual average calculation unit (71) that calculates an individual average charging rate for each storage battery using charging rate data for each storage battery over a predetermined period of time, an offset calculation unit (73) that calculates an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate, and a power command setting unit (50) that sets an individual power command for each storage battery using the individual offset power for each storage battery.

[0118] According to the above aspect, since the individual power command for each storage battery is set so that the individual average charging rate of each storage battery approaches the overall average charging rate in accordance with the charging rate of the multiple storage batteries, the variation in the charging rate of each storage battery can be suppressed, and the life of the storage batteries and the system can be extended. In addition, since the variation in the charging rate of each storage battery can be suppressed, it is possible to suppress the deterioration of only a specific storage battery, which reaches the upper or lower limit of the charging rate at which the battery system can operate normally. As a result, even if the storage battery deteriorates due to aging or the like, it is possible to suppress the charging rate value reaching the allowable upper or lower limit of the operable range of the power control system, which causes the entire system to stop.

[0119] In a battery control system (10, 10a) according to a second aspect of the present disclosure, in the above-mentioned first aspect, the individual average calculation unit (71) calculates a moving average of the charging rates of the respective storage batteries during the predetermined period as the individual average charging rate.

[0120] According to the above aspect, by calculating a moving average of the storage battery's charging rate and calculating an individual average charging rate, it is possible to accurately grasp the trend of changes in the charging rate even in an operation pattern in which the charging rate changes instantaneously.

[0121] In a battery control system (10, 10a) according to a third aspect of the present disclosure, in the first aspect, the individual average calculation unit (71) identifies a maximum charging rate and a minimum charging rate for each storage battery in the specified period, and calculates the individual average charging rate using the identified maximum charging rate and minimum charging rate.

[0122] According to the above aspect, since the overall average charging rate can be calculated with a small memory capacity, the cost of calculating the individual average charging rates can be reduced.

[0123] In a battery control system (10, 10a) according to a fourth aspect of the present disclosure, in the first aspect, the individual average calculation unit (71) calculates a moving average charging rate, which is a moving average of the charging rates of the storage batteries in the specified period, and calculates the individual average charging rate using a maximum moving average charging rate, which is the maximum value of the moving average charging rates, and a minimum moving average charging rate, which is the minimum value of the moving averages.

[0124] According to the above aspect, by calculating the individual average charging rate using the maximum moving average charging rate and the minimum moving average charging rate, it is possible to accurately grasp the tendency of changes in the charging rate even in a driving pattern in which the charging rate changes instantaneously, while suppressing calculation costs.

[0125] In a battery control system (10, 10a) according to a fifth aspect of the present disclosure, in any one of the first to fourth aspects, the overall average calculation unit (72) calculates the average of each moving average of the charging rate for each storage battery during the specified period as the overall average charging rate.

[0126] According to the above aspect, by calculating the average of each moving average of the charging rate for each storage battery as the overall average charging rate, it is possible to accurately grasp the trend of change in the charging rate even in an operation pattern in which the charging rate changes instantaneously.

[0127] A battery control system (10, 10a) according to a sixth aspect of the present disclosure is any one of the first to fourth aspects, wherein the overall average calculation unit (72) identifies a maximum charging rate and a minimum charging rate for each storage battery in the specified period, and calculates the overall average charging rate using the identified maximum charging rate and minimum charging rate.

[0128] According to the above aspect, the overall average charging rate can be calculated with a small memory capacity, so that the cost of calculating the overall average charging rate can be reduced.

[0129] A battery control system (10, 10a) according to a seventh aspect of the present disclosure is any one of the first to fourth aspects, wherein the overall average calculation unit (72) calculates a moving average charging rate, which is a moving average of the charging rates of the storage batteries in the specified period, and calculates the overall average charging rate using a maximum moving average charging rate, which is the maximum value of the moving average charging rates, and a minimum moving average charging rate, which is the minimum value of the moving average charging rates.

[0130] According to the above aspect, by calculating the overall average charging rate using the maximum moving average charging rate and the minimum moving average charging rate, it is possible to accurately grasp the trend of changes in the charging rate even in a driving pattern in which the charging rate changes instantaneously, while suppressing calculation costs.

[0131] In a battery control system (10, 10a) according to an eighth aspect of the present disclosure, in the first aspect, the offset calculation unit calculates, for each storage battery, an individual offset power for bringing the individual average charging rate closer to the target average charging rate, using a target average charging rate that is a fixed value instead of the overall average charging rate.

[0132] According to the above aspect, even when a stopped storage battery is restored, by using a fixed target average charging rate instead of the overall average charging rate, which changes depending on the charging rate of the storage battery 5 in the row being restored, it is possible to calculate the individual offset power without being affected by the restoration or disconnection of the storage battery.

[0133] A battery control system (10, 10a) according to a ninth aspect of the present disclosure is a battery control system applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes a charging rate determination unit (74) that determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period, an offset calculation unit (75) that calculates individual offset power for bringing closer to zero a difference between an allowable upper limit value of a range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and a difference between an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate, and a power command setting unit (50) that sets individual power commands for each of the storage batteries using the individual offset power for each of the storage batteries.

[0134] According to the above aspect, the storage battery is operated in a state where the maximum moving average charging rate and the minimum moving average charging rate of the storage battery are secured with equal margins with respect to the upper and lower limits of the operable range of the storage battery, thereby stabilizing the range in which the charging rate changes and reducing the possibility that the charging rate will reach either of the upper or lower limits of the operable range. In other words, the variation in the charging rate of each storage battery can be reduced, and the life of the storage battery and the battery system can be extended.

[0135] A battery control system (10, 10a) according to a tenth aspect of the present disclosure is, in any one of the first, eighth or ninth aspects described above, wherein when the battery system (1, 1a) is a system that uses DC power, the offset calculation unit (73) further calculates an intercept in a linear equation of power-voltage for the storage batteries using each of the individual offset powers, and the power command setting unit (50) sets an individual power command for each of the storage batteries using the intercept instead of the individual offset power for each of the storage batteries.

[0136] According to the above aspect, the offset calculation unit further calculates an intercept using the individual offset power, and the power command setting unit sets an individual power command for each storage battery using the intercept. Therefore, when the battery system is a system that uses DC power, it is possible to easily control the power command-voltage, and to stabilize the control of the battery system.

[0137] An electricity supply and demand system (100, 100a) according to an eleventh aspect of the present disclosure is an electricity supply and demand system comprising a battery system (1, 1a) having a plurality of storage batteries, and a battery control system (10, 10a) according to any one of the first, eighth or ninth aspects.

[0138] A battery control method according to a twelfth aspect of the present disclosure is a battery control method applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes the steps of: calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period; calculating an individual average charging rate for each storage battery using charging rate data for each storage battery over a predetermined period; calculating an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate; and setting an individual power command for each storage battery using the individual offset power for each storage battery.

[0139] A battery control method according to a 13th aspect of the present disclosure is, in the above 12th aspect, in the step of calculating the individual offset power, a target average charging rate that is a fixed value is used instead of the overall average charging rate to calculate an individual offset power for each storage battery to bring the individual average charging rate closer to the target average charging rate.

[0140] A battery control method according to a fourteenth aspect of the present disclosure is a battery control method applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes the steps of: determining an upper representative charging rate and a lower representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; calculating individual offset powers for bringing closer to zero the difference between the upper representative charging rate and an allowable upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally, and the difference between the upper representative charging rate and an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally; and setting individual power commands for each of the storage batteries using the individual offset powers for each of the storage batteries.

[0141] A battery control program according to a fifteenth aspect of the present disclosure is a battery control program applied to a battery system (1, 1a) having a plurality of storage batteries (5), and causes a computer to execute the following processes: a process of calculating an overall average charging rate that serves as a benchmark for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period of time; a process of calculating an individual average charging rate for each storage battery using charging rate data for each storage battery over a predetermined period of time; a process of calculating an individual offset power for each storage battery to bring the individual average charging rate closer to the overall average charging rate; and a process of setting an individual power command for each storage battery using the individual offset power for each storage battery.

[0142] A battery control method according to a 16th aspect of the present disclosure is, in the above-mentioned 15th aspect, in the step of calculating the individual offset power, a target average charging rate that is a fixed value is used instead of the overall average charging rate to calculate an individual offset power for each storage battery to bring the individual average charging rate closer to the target average charging rate.

[0143] A battery control program according to a seventeenth aspect of the present disclosure is a battery control program applied to a battery system (1, 1a) having a plurality of storage batteries (5), and causes a computer to execute a process of determining an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period of time, a process of calculating individual offset power for bringing closer to zero the difference between the upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and the difference between the lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate, and a process of setting individual power commands for each of the storage batteries using the individual offset power for each of the storage batteries. [Explanation of symbols]

[0144] 1,1a: Battery system 2: Power system 3: Substation 4:AC Link 5(5a~5d):Storage battery 6: Grid monitoring system 7 (7a to 7d): Power conversion device 7'(7a'~7d'): Power conversion device 8: DC link 9: AC / DC converter 10, 10a: Battery control system 11: CPU 12: Main memory 13:Secondary storage device 14: Communication interface 15: Input device 16: Display 18: Bus 20: Deterioration state evaluation section 30: Data Management Department 40: Share adjustment rate setting section 50: Power command setting section 60: Storage section 70, 70a: Individual offset power setting section 71:Individual average calculation section 72: Overall average calculation section 73: Offset calculation section 74: Charging rate determination section 75: Offset calculation section 100,100a: Electricity supply and demand system

Claims

1. A battery control system applied to a battery system including a plurality of storage batteries, an overall average calculation unit that calculates an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries for a predetermined period; an individual average calculation unit that calculates an individual average charging rate for each of the storage batteries using charging rate data for each of the storage batteries during a predetermined period; an offset calculation unit that calculates, for each of the storage batteries, an individual offset power for bringing the individual average charging rate closer to the overall average charging rate; a power command setting unit that sets an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries; A battery control system comprising:

2. The battery control system according to claim 1 , wherein the individual average calculation unit calculates a moving average of the charging rates of the respective storage batteries during the predetermined period as the individual average charging rate.

3. 2. The battery control system according to claim 1, wherein the individual average calculation unit identifies a maximum charging rate and a minimum charging rate for each of the storage batteries during the specified period, and calculates the individual average charging rate using the identified maximum charging rate and minimum charging rate.

4. 2. The battery control system according to claim 1, wherein the individual average calculation unit calculates a moving average charging rate that is a moving average of the charging rates of each of the storage batteries during the specified period, and calculates the individual average charging rate using a maximum moving average charging rate that is a maximum value of each of the moving average charging rates and a minimum moving average charging rate that is a minimum value of each of the moving averages.

5. The battery control system according to claim 1 , wherein the overall average calculation unit calculates an average of moving averages of the charging rates of the respective storage batteries during the predetermined period as the overall average charging rate.

6. 2. The battery control system according to claim 1, wherein the overall average calculation unit identifies a maximum charging rate and a minimum charging rate for each of the storage batteries during the specified period, and calculates the overall average charging rate using the identified maximum charging rate and minimum charging rate.

7. 2. The battery control system according to claim 1, wherein the overall average calculation unit calculates a moving average charging rate that is a moving average of the charging rates of the storage batteries during the specified period, and calculates the overall average charging rate using a maximum moving average charging rate that is a maximum value of the moving average charging rates and a minimum moving average charging rate that is a minimum value of the moving average charging rates.

8. 2. The battery control system according to claim 1, wherein the offset calculation unit calculates, for each storage battery, an individual offset power for bringing the individual average charging rate closer to the target average charging rate by using a target average charging rate that is a fixed value instead of the overall average charging rate.

9. A battery control system applied to a battery system including a plurality of storage batteries, a charging rate determination unit that determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period of time; an offset calculation unit that calculates an individual offset power for bringing a difference between an allowable upper limit of a range of charging rates at which the plurality of storage batteries can be normally operated and the upper limit representative charging rate, and a difference between an allowable lower limit of a range of charging rates at which the plurality of storage batteries can be normally operated and the lower limit representative charging rate, closer to zero; a power command setting unit that sets an individual power command for each of the storage batteries using the individual offset power of each of the storage batteries; A battery control system comprising:

10. When the battery system is a system that uses DC power, the offset calculation unit further calculates an intercept in a linear equation of power-voltage related to the storage battery using each of the individual offset powers; 10. The battery control system according to claim 1, wherein the power command setting unit sets an individual power command for each of the storage batteries by using the intercept instead of the individual offset power of each of the storage batteries.

11. A battery system including a plurality of storage batteries; A battery control system according to any one of claims 1, 8 and 9. An electricity supply and demand system comprising:

12. A battery control method applied to a battery system including a plurality of storage batteries, calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for a predetermined period of time for the plurality of storage batteries; calculating an individual average charging rate for each of the storage batteries using charging rate data for each of the storage batteries during a predetermined period; calculating an individual offset power for each of the storage batteries to bring the individual average charging rate closer to the overall average charging rate; setting an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries; The battery control method includes the steps of:

13. 13. The battery control method according to claim 12, wherein in the step of calculating the individual offset power, a target average charging rate that is a fixed value is used instead of the overall average charging rate to calculate an individual offset power for each storage battery to bring the individual average charging rate closer to the target average charging rate.

14. A battery control method applied to a battery system including a plurality of storage batteries, determining an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system during a predetermined period; calculating an individual offset power for bringing a difference between an allowable upper limit of a range of charging rates at which the plurality of storage batteries can be normally operated and the upper limit representative charging rate, and a difference between an allowable lower limit of a range of charging rates at which the plurality of storage batteries can be normally operated and the lower limit representative charging rate closer to zero; setting an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries; The battery control method includes the steps of:

15. A battery control program applied to a battery system including a plurality of storage batteries, A process of calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for a predetermined period of time for the plurality of storage batteries; calculating an individual average charging rate for each of the storage batteries using charging rate data for each of the storage batteries during a predetermined period; A process of calculating an individual offset power for each of the storage batteries so as to bring the individual average charging rate closer to the overall average charging rate; setting an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries; A battery control program for causing a computer to execute the above.

16. 16. The battery control program according to claim 15, wherein in the process of calculating the individual offset power, a target average charging rate that is a fixed value is used instead of the overall average charging rate to calculate an individual offset power for each storage battery to bring the individual average charging rate closer to the target average charging rate.

17. A battery control program applied to a battery system including a plurality of storage batteries, determining an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; A process of calculating individual offset power for bringing a difference between an allowable upper limit value of a range of charging rates at which the plurality of storage batteries can be normally operated and the upper limit representative charging rate, and a difference between an allowable lower limit value of a range of charging rates at which the plurality of storage batteries can be normally operated and the lower limit representative charging rate, closer to zero; setting an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries; A battery control program for causing a computer to execute the above.

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