Power supply and demand system, battery control system, battery control method, and program

Abstract

To extend the life of a battery system as a whole without reducing the operating efficiency of the battery system.SOLUTION: A battery control system 10 includes a degradation state evaluation unit 20 that sequentially selects a storage battery to be evaluated for the degradation state, and calculates a degradation evaluation value related to the degradation state of the storage battery to be evaluated using the voltage value or current value when charging and discharging of the storage battery to be evaluated according to a preset charge and discharge pattern, a data management unit 30 that associates the identification information of the storage battery with the degradation evaluation value and stores them in a memory unit 60, a sharing adjustment rate setting unit 40 that sets a sharing adjustment rate using the degradation evaluation values of a plurality of storage batteries, and a power command setting unit 50 that uses the sharing adjustment rate to set individual power commands for each operational storage battery that is a storage battery other than the storage battery to be evaluated.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, in a battery system having a plurality of storage batteries, it has been proposed to monitor the deterioration state of each storage battery and to perform control to suppress the deterioration state of a storage battery that is in a more deteriorated state among the plurality of storage batteries. For example, Patent Document 1 discloses that attention is paid to the deterioration state and temperature state of the storage battery determined based on the charging rate (SOC: State Of Charge) of the storage battery, and charging and discharging of each storage battery is controlled so that the deterioration states of the plurality of storage batteries are equal. More specifically, Patent Document 1 discloses that for a storage battery in an advanced deteriorated state, control is performed to increase the limit on the maximum current value and the limit on the end voltage of charging and discharging in order to suppress the deterioration state of the storage battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5932190 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a method for estimating the degree of deterioration for one day using operation history data, adding the estimated degree of deterioration to the degree of deterioration for the previous day to obtain the current degree of deterioration, and further measuring the full charge capacity of the storage battery periodically and correcting the estimated degree of deterioration using the measured value. Thus, according to Patent Document 1, the full charge capacity of the storage battery is measured periodically to correct the degree of deterioration, making it possible to obtain a relatively accurate degree of deterioration.

[0005] However, periodic measurements of the full charge capacity are generally performed with the battery system stopped, which can reduce the operational efficiency of the battery system.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide an electric power supply and demand system, a battery control system, a battery control method, and a program that can extend the life of the battery system as a whole without reducing the operational efficiency of the battery system. [Means for solving the problem]

[0007] One aspect of the present disclosure is a battery control system applied to a battery system having a plurality of storage batteries, the battery control system including: a degradation state evaluation unit that sequentially selects storage batteries to be evaluated for their degradation state, and calculates a degradation evaluation value related to the degradation state of the storage battery to be evaluated using a voltage value or a current value when charging and discharging of the storage battery to be evaluated according to a predetermined charge and discharge pattern flow; a data management unit that associates identification information of the storage battery with the degradation evaluation value and stores them in a memory unit; a sharing adjustment rate setting unit that sets a sharing adjustment rate using the degradation evaluation values ​​of the plurality of storage batteries; and a power command setting unit that uses the sharing adjustment rate to set individual power commands for each operational storage battery that is a storage battery other than the storage battery to be evaluated.

[0008] One aspect of the present disclosure is an electric power supply and demand system including a battery system including a plurality of storage batteries and the battery control system.

[0009] One aspect of the present disclosure is a battery control method applied to a battery system including a plurality of storage batteries, in which a computer executes a degradation state evaluation process for sequentially selecting storage batteries to be evaluated for their degradation state, and calculating a degradation evaluation value relating to the degradation state of the storage battery to be evaluated using a voltage value or a current value when charging and discharging of the storage battery to be evaluated according to a predetermined charge and discharge pattern method, a data management process for associating identification information of the storage battery with the degradation evaluation value and storing them in a memory unit, a sharing adjustment rate setting process for setting a sharing adjustment rate using the degradation evaluation values ​​of the plurality of storage batteries, and a power command setting process for setting individual power commands for each operational storage battery, which is a storage battery other than the storage battery to be evaluated, using the sharing adjustment rate.

[0010] One aspect of the present disclosure is a program for causing a computer to function as the battery control system. Effect of the Invention

[0011] The life of the battery system as a whole can be extended without reducing the operational efficiency of the battery system. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a schematic configuration of an electricity supply and demand system according to a first embodiment of the present disclosure. [Diagram 2] 1 is a diagram illustrating an example of a hardware configuration of a battery control system according to a first embodiment of the present disclosure. [Diagram 3] 2 is a functional configuration diagram showing an example of functions of the battery control system according to the first embodiment of the present disclosure. FIG. [Figure 4] 2 is a functional configuration diagram showing an example of functions of a degradation state assessment unit according to the first embodiment of the present disclosure. FIG. [Diagram 5] FIG. 4 is a diagram showing an example of a transition of a charging rate when charge / discharge control according to the first embodiment of the present disclosure is performed. [Figure 6] 6 is a diagram showing an example of a change in battery voltage when charge / discharge control is performed with the same charge / discharge pattern as in FIG. 5. FIG. [Figure 7] FIG. 7 is an enlarged view of the state where adjustment charging shown in FIG. 6 is being performed. [Figure 8] FIG. 7 is an enlarged view of the state where the regulating discharge shown in FIG. 6 is being performed. [Figure 9] FIG. 13 is a diagram showing an example of a sharing adjustment rate of a storage battery. [Figure 10] FIG. 9 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 11] 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 12] FIG. 9 shows examples of SOC when the sharing adjustment rate is set to 0.8 and 1.2 for comparison. [Figure 13] 4 is a flowchart showing an example of a procedure of a degradation state evaluation process executed by the battery control system according to the first embodiment of the present disclosure. [Figure 14] 5 is a flowchart showing an example of a procedure of an individual power command setting process executed by the battery control system according to the first embodiment of the present disclosure. [Figure 15] FIG. 2 is a diagram for explaining the effect of the battery control system according to the first embodiment of the present disclosure. [Figure 16] 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 17] FIG. 11 is a functional configuration diagram showing an example of functions of a battery control system according to a second embodiment of the present disclosure. [Figure 18] FIG. 11 is a diagram illustrating a relationship between an individual power command and a bus voltage of a DC link according to a second embodiment of the present disclosure. [Figure 19] 11 is a diagram showing an example of the relationship between the slope of storage batteries with different SOH and individual power commands. FIG. [Figure 20] 1 is a diagram for explaining the occurrence of variation in the central value of the charging rate among storage batteries over time. FIG. [Figure 21]FIG. 11 is a functional configuration diagram showing an example of functions of a battery control system according to a third embodiment of the present disclosure. [Figure 22] FIG. 13 is a functional configuration diagram showing an example of functions included in an individual offset power setting unit according to the third embodiment of the present disclosure. [Figure 23] FIG. 11 is a diagram for explaining the effect of the battery control system according to the third embodiment of the present disclosure. [Figure 24] 10 is a diagram for explaining individual offset power when a battery system is connected to a DC link. FIG. [Diagram 25] FIG. 10 is a diagram for explaining the tendency for the center of SOC of the entire battery system to shift over time. [Figure 26] FIG. 11 is a functional configuration diagram showing an example of functions of a battery control system according to a fourth embodiment of the present disclosure. [Figure 27] FIG. 13 is a functional configuration diagram showing an example of functions included in an overall offset power setting unit according to a fourth embodiment of the present disclosure. [Figure 28] FIG. 13 is a diagram showing a functional configuration of an overall offset power setting unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [First embodiment] Hereinafter, a power supply and demand system, a battery control system, a battery control method, and a program according to a first embodiment of 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.

[0014] 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.

[0015] Each storage battery 5 is chargeable and dischargeable, 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. The configuration of the storage battery 5 may be any known technology and is not particularly limited.

[0016] 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.

[0017] 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 a system power request to be made to the battery system 1 and transmits this to the battery control system 10.

[0018] 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 via a bus 18.

[0019] 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.

[0020] 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, and a storage unit 60.

[0021] 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.

[0022] 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.

[0023] Fig. 4 is a functional configuration diagram showing an example of functions included in the degradation state evaluation unit 20. As shown in Fig. 4, the degradation state evaluation unit 20 includes, for example, a selection unit 21, a measurement execution unit 22, a restoration control unit 23, and an evaluation value calculation unit 24. When evaluating the degraded state, the selection unit 21 selects, in order, the storage batteries 5 to be evaluated. Specifically, the selection unit 21 selects one or more storage batteries 5 to be evaluated according to a predetermined algorithm during degradation state evaluation. Then, when the measurement execution unit 22 described later finishes the degradation state evaluation of the storage battery 5 selected as the evaluation target, the selection unit 21 selects one or more storage batteries 5 to be evaluated next as the evaluation target. The selection unit 21 repeats the selection until all the storage batteries 5a to 5d included in the battery system 1 are selected as evaluation targets. Note that, for convenience of explanation, in this embodiment, a case where the selection is performed in order of the storage batteries 5a, 5b, 5c, and 5d will be described as an example.

[0024] The measurement execution unit 22 controls the charging and discharging of the storage battery 5 to be evaluated according to a preset charging and discharging pattern, and acquires the voltage value or current value at this time. Specifically, the measurement execution unit 22 issues a charging and discharging command according to a predetermined charging and discharging pattern to the power conversion device 7 corresponding to the storage battery 5 to be evaluated. As a result, the power conversion device 7 is driven according to the charging and discharging pattern, thereby realizing charging and discharging according to the charging and discharging pattern.

[0025] The charge and discharge patterns include, for example, a charge pattern for charging to a fully charged state and a discharge pattern for discharging to a lower limit of the charge amount. The charge pattern may include an adjusted charge pattern for changing the charging current value stepwise or continuously near the fully charged state. In this way, by including an adjusted charge pattern, the storage battery 5 can be brought closer to a fully charged state compared to a case where charging is performed with only a uniform current (e.g., 1C).

[0026] The discharge pattern may include an adjusted discharge pattern that changes the discharge current value stepwise or continuously near the lower limit of the charge amount. By including the adjusted discharge pattern, the storage battery 5 can be brought closer to the lower limit of the charge amount compared to the case where the battery is discharged at a uniform current (e.g., 1C).

[0027] Fig. 5 is a diagram showing an example of the transition of the state of charge (SOC) when charge / discharge control according to this embodiment is performed. Fig. 6 is a diagram showing an example of the transition of the battery voltage when charge / discharge control is performed with the same charge / discharge pattern as Fig. 5. In Figs. 5 and 6, the solid lines show an example of the transition of the storage battery to be evaluated, and the dotted lines show an example of the transition of an arbitrary storage battery other than the storage battery to be evaluated (operated storage battery).

[0028] FIG. 7 is an enlarged view of the state of charge shown in FIG. 6. FIG. 7 illustrates an example in which the current value is changed stepwise in the state of charge. As shown in FIG. 7, in the state of charge, it is preferable to gradually reduce the charging current value and make the battery voltage (open voltage) when the charging current is stopped as close as possible to the value of SOC100% (fully charged state). Here, an example in which the charging current is changed stepwise is shown, but the present invention is not limited to this. For example, when the power conversion device 7 can charge the storage battery 5 while maintaining the maximum battery voltage, CC-CV charging may be used. That is, charging may be performed by continuously changing the current until a predetermined charging voltage set near the maximum battery voltage is reached, and after the predetermined charging voltage is reached, charging may be performed until the battery is fully charged while avoiding an overvoltage charging state by switching to CV.

[0029] Also, the battery voltage (open circuit voltage) when the charging current is stopped is preferably a value of SOC100%, but it can be other than that. For example, if the SOC is 80% and a capacity test is performed for SOC 80% from SOC 80% to 0%, the full charge capacity of the test result can be multiplied by 100% / 80% = 1.25 to convert it into the result of a capacity test for SOC 100%.

[0030] FIG. 8 is an enlarged view of the state of the regulated discharge shown in FIG. 6. FIG. 8 illustrates an example in which the current value is changed stepwise in the regulated discharge. As shown in FIG. 8, in the regulated discharge, it is preferable to gradually reduce the discharge current value and make the battery voltage (open voltage) when the discharge current is stopped as close as possible to the value in the SOC 0% state. Although an example in which the discharge current is changed stepwise has been shown here, if the power conversion device 7 can discharge while maintaining the minimum battery voltage of the storage battery 5, CC-CV discharge may be used. That is, the current may be continuously changed to discharge until a predetermined discharge voltage set near the minimum battery voltage is reached, and after the predetermined discharge voltage is reached, the current may be switched to CV to discharge to the minimum battery voltage. Also, the battery voltage (open circuit voltage) when the discharge current is stopped is preferably a value of SOC 0%, but it can be other than that. For example, if the SOC is 20% and a capacity test is performed for SOC 80% from SOC 100% to 20%, the full charge capacity of the test result can be converted to the result of a capacity test for SOC 100% by multiplying it by 100% / 80% = 1.25.

[0031] As shown in Figures 5 and 6, settling times are provided between the charge pattern and the discharge pattern, between the discharge pattern and the recovery process, and between the end of the recovery process and the end of measurement to stop charging and discharging. By providing settling times, it becomes possible to stabilize the state of charge of the storage battery.

[0032] After the measurement by the measurement execution unit 22 is completed, in other words, after the charge / discharge control based on a predetermined charge / discharge pattern is completed, the return control unit 23 controls the charge / discharge of the storage battery to be evaluated (e.g., 5a) so that the charge state of the storage battery to be evaluated approaches the charge state of the operating storage batteries (e.g., 5b to 5d). Then, when the charge state of the storage battery to be evaluated (e.g., 5a) and the charge state of the operating storage batteries (e.g., 5b to 5d) satisfy a predetermined condition, the return control unit 23 returns the storage battery to be evaluated as an operating storage battery (see the return process in FIG. 5 and FIG. 6). For example, the recovery control unit 23 may recover the storage battery to be evaluated as an operational battery when the difference between the average cell voltage of the storage battery to be evaluated and the average value of the average cell voltage of the operational storage batteries falls within a predetermined range. Also, the charging rate may be used instead of the average cell voltage.

[0033] The evaluation value calculation unit 24 calculates a degradation evaluation value for evaluating the degradation state of the storage battery 5 to be evaluated, based on the current value or voltage value when charge / discharge control is performed by the measurement execution unit 22. For example, the evaluation value calculation unit 24 receives battery information (current value, voltage value, temperature, etc.) from the storage battery 5 to be evaluated, and calculates a degradation evaluation value based on the received battery information.

[0034] The degradation evaluation value is, for example, an evaluation value that indicates a decrease in the current full charge capacity relative to the initial full charge capacity of the storage battery 5, and one example is SOH (State of Health). SOH is the ratio of the latest (current) full charge capacity to the initial full charge capacity (capacity of an undegraded battery). In other words, SOH is a value obtained by normalizing the latest (current) full charge capacity [Ah] by a common battery capacity [Ah] (for example, the maximum full charge capacity at the time of battery manufacture, etc.). The evaluation value calculation unit 24 calculates the latest full charge capacity (Ah) by, for example, integrating the current value when the storage battery 5 to be evaluated is changed from a fully charged state to a lower limit charge state, or from the lower limit charge state to a fully charged state. Then, for example, the evaluation value calculation unit 24 calculates the SOH by dividing the latest full charge capacity by the full charge capacity at the start (initial) of operation of the battery system 1. In addition, in the process of calculating the latest full charge capacity, correction may be made based on differences in test conditions (rate, temperature, etc.). The method for evaluating the deterioration state of a battery is not limited to the above example, and any known technique for evaluating the deterioration state of a battery may be used as appropriate.

[0035] After calculating the deterioration evaluation values ​​for all the storage batteries 5a-5d, the evaluation value calculation unit 24 outputs deterioration evaluation information that associates the identification information of each storage battery with the deterioration evaluation value to the data management unit (see FIG. 3). The deterioration evaluation information may include time information, battery information of each storage battery 5a-5d acquired by the measurement execution unit 22, and the like.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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).

[0040] Sharing adjustment rate α(i)={1+K(ΔSOH(i) / SOHave)} (1)

[0041] 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.

[0042] Sharing adjustment rate α(1)={1+K(ΔSOH(1) / SOHave)}

[0043] 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 can be. 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 assigned to the operational storage batteries does not exceed the system required power. Moreover, when the adjustment gain K is set to zero, the sharing adjustment rate of each of the storage batteries 5a to 5d is 1, so in this case, there is no increase or decrease in the power sharing according to SOH(i). That is, the system required power is allocated equally to each storage battery.

[0044] 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.

[0045] After calculating the sharing adjustment rate for each of the storage batteries 5a to 5d, 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.

[0046] 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 of the batteries 5a to 5d 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 batteries for which degradation evaluation is performed by the above-mentioned degradation state evaluation unit 20 are excluded from the operational batteries.

[0047] 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).

[0048] Pdiv(i)=Pall×(1 / N)×α(i) (2)

[0049] In the above formula (2), N represents the number of operating storage batteries. For example, when the state-of-deterioration evaluation by the above-described state-of-deterioration evaluation unit 20 is not performed, the storage batteries 5a to 5d can be the operating storage batteries, and during the period when the state-of-deterioration evaluation is being performed, the storage batteries other than the evaluation target can become the operating storage batteries.

[0050] As can be seen from formula (2), a larger individual power command is set for the operating storage battery with a higher deterioration evaluation value (higher soundness) than for the operating storage battery with a lower deterioration evaluation value. When the power command setting unit 50 assigns an individual power command Pdiv(i) to each operating storage battery, it transmits the individual power command Pdiv(i) to the power conversion device 7 corresponding to each operating storage battery. Thereby, charge and discharge control according to the individual power command Pdiv is performed in each operating storage battery.

[0051] For example, when the SOH(2) of the storage battery 5b is higher than the SOH(1) of the storage battery 5a, that is, SOH(1) < SOH(2), and as shown in FIG. 9, the sharing adjustment rate α(1) of the storage battery 5a is set to 0.8 and the sharing adjustment rate α(2) of the storage battery 5b is set to 1.2, an example of the individual power command, charge and discharge current, and SOC is compared and shown in FIGS. 10 to 12, respectively. In FIGS. 10 to 12, the solid line indicates the storage battery 5a and the broken line indicates the storage battery 5b. As shown in FIGS. 10 to 12, since the individual power command of the storage battery 5b is larger than that of the storage battery 5a, the charge and discharge current of the storage battery 5b becomes larger than that of the storage battery 5a, and the amplitude of the SOC also becomes a larger value than that of the storage battery 5a.

[0052] Next, the operation of the battery control system 10 according to the present embodiment will be described. FIG. 13 is a flowchart showing an example of the procedure of the state-of-deterioration evaluation process executed by the battery control system 10 according to the present embodiment. The state-of-deterioration evaluation process shown below is started when the preset start condition of the state-of-deterioration evaluation is satisfied. Hereinafter, for convenience of explanation, a case where the state-of-deterioration evaluation is performed in the order of the storage batteries 5a, 5b, 5c, and 5d will be exemplified and described.

[0053] First, the battery control system 10 selects a storage battery 5a to be evaluated for a deterioration state evaluation (SA1), controls the charging and discharging of the storage battery 5a to be evaluated in accordance with a preset charging and discharging pattern, and obtains battery information such as the voltage value, current value, temperature, etc. of the storage battery 5a at this time from the battery system 1 (SA2).

[0054] When the charge / discharge control of the storage battery 5a to be evaluated is completed, a deterioration evaluation value is calculated from the acquired battery information (SA3), and the identification information "#1" of the storage battery 5a to be evaluated and the deterioration evaluation value are associated and stored in an internal memory (SA4). Next, a recovery process is performed (SA5). In the recovery process, the charge / discharge of the storage battery 5a to be evaluated is controlled so that the charging rate of the storage battery 5a to be evaluated approaches the charging rates of the operational batteries 5b to 5d. Then, when the charging rate of the storage battery 5a to be evaluated satisfies a predetermined condition defined in relation to the charging rates of the operational batteries, the storage battery 5a to be evaluated is recovered as an operational battery.

[0055] Next, it is determined whether all the storage batteries 5a to 5d have been selected as the evaluation target (SA6). In this case, since all the storage batteries 5a to 5d have not been selected (SA6: NO), the process returns to step SA1, and the unselected storage battery 5b is selected as the evaluation target. Then, a degradation state evaluation is performed for the storage battery 5b. Here, if the storage battery 5b is selected as the evaluation target, the operation storage batteries are the storage batteries 5a, 5c, and 5d. Then, the same process is performed for the storage batteries 5c and 5d. If it is determined in step SA6 that all the storage batteries 5a to 5d have been selected as the evaluation target (SA6: YES), degradation evaluation information that associates the identification information #1 to #4 of each of the storage batteries 5a to 5d with the degradation evaluation value is output (SA7), and the process ends. As a result, the degradation evaluation value of each of the storage batteries 5a to 5d is stored in the storage unit 60.

[0056] In this way, when the deterioration evaluation value is updated and, for example, a condition for starting calculation of the sharing adjustment rate is satisfied, the battery control system 10 executes a sharing adjustment rate setting process, for example. In the sharing adjustment rate setting process, a sharing adjustment rate is calculated based on the latest deterioration evaluation value of each storage battery. The calculated sharing adjustment rate is associated with the identification information of each storage battery 5a-5d and stored in the storage unit 60. As a result, the latest sharing adjustment rate of each storage battery 5a-5d is stored in the storage unit 60, and the sharing adjustment rate is updated.

[0057] Next, an individual power command setting process executed by the battery control system 10 will be described with reference to Fig. 14. Fig. 14 is a flowchart showing an example of the procedure of the individual power command setting process. This process starts when the operation of the battery system 1 is started, and ends when the operation is ended.

[0058] First, the battery control system 10 acquires the sharing adjustment rate α(i) of each of the storage batteries 5a-5d from the storage unit 60 (SB1). Next, it is determined whether or not a degradation state is being evaluated (SB2). As a result, if a degradation state is being evaluated (SB2: YES), the system identifies operational batteries excluding the storage battery to be evaluated (SB3). For example, if the storage battery 5a is selected as the storage battery to be evaluated, the storage batteries 5b-5d are set as operational batteries. On the other hand, if a degradation state is not being evaluated (SB2: NO), the storage batteries 5a-5d are identified as operational batteries.

[0059] Next, for each operational battery, an individual power command is set using the sharing adjustment rate α(i) (SB4), and each individual power command is sent to each operational battery (SB5). This makes it possible to perform charge / discharge control that reflects the deterioration evaluation value (e.g., SOH(i)) of each operational battery. Next, it is determined whether or not the control of the battery system 1 has ended (SB6), and if not (SB6: NO), the process returns to step SB2 and repeats the subsequent processes. On the other hand, if it has ended (SB6: YES), this process ends.

[0060] As described above, the battery control system 10 according to this embodiment includes a degradation state evaluation unit 20 that sequentially selects storage batteries 5 to be evaluated for their degradation state, and calculates a degradation evaluation value relating to the degradation state of the storage battery to be evaluated using a voltage value or a current value when charging and discharging of the storage battery to be evaluated is controlled according to a preset charge and discharge pattern, and a data management unit 30 that associates identification information of the storage battery with the degradation evaluation value and stores them in the storage unit 60. As a result, the degradation evaluation values ​​of the storage batteries 5a to 5d are stored in the storage unit 60, and the degradation evaluation value in the storage unit 60 is updated every time a degradation state evaluation is performed.

[0061] Furthermore, according to this embodiment, the battery control system 10 includes a sharing adjustment rate setting unit 40 that sets a sharing adjustment rate α(i) using the deterioration evaluation values ​​of the multiple storage batteries 5a to 5d stored in the memory unit 60, and a power command setting unit 50 that sets individual power commands for each operational storage battery using the sharing adjustment rate α(i). This makes it possible to operate the operational batteries that are not the batteries being evaluated while performing the degradation state evaluation. In this case, the operational batteries are controlled based on the individual power commands set using the sharing adjustment rate α(i) calculated based on the degradation evaluation value of each battery. This makes it possible to suppress the variation in the degradation evaluation value (SOH) between the batteries, and to extend the life of the battery system as a whole.

[0062] FIG. 15 is a diagram for explaining the effect of the battery control system 10 according to the first embodiment of the present disclosure. FIG. 15 shows an example of battery life when the battery control system 10 according to the present embodiment is applied and when it is not applied, so that it can be compared. As shown in FIG. 15, in the case of no control, the same individual power command is given to the storage battery regardless of the SOH, so that the storage battery with a low SOH in the initial state will reach the end of its life first. On the other hand, in the case of applying the battery control system 10 according to the present embodiment, more individual power commands are given to the storage battery with a high SOH, and relatively fewer individual power commands are given to the storage battery with a low SOH. This makes it possible to gradually reduce the variation in SOH of each storage battery. This makes it possible to extend the life of the storage battery that had a low SOH in the initial state, and therefore, as shown in FIG. 15, it is possible to extend the life of the entire battery system.

[0063] Second Embodiment Next, a power supply and demand system, a battery control system, a battery control method, and a program according to a second embodiment of the present disclosure will be described with reference to the drawings. 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 a case has been described in which the battery system 1 is connected to the AC link 4 via the power conversion device 7. In contrast, in a power supply and demand system 100a according to this embodiment, as shown in FIG. 16, the battery system 1a is connected to a 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 via an AC / DC converter 9.

[0064] Fig. 17 is a functional configuration diagram showing an example of functions of a battery control system 10a according to this embodiment. As shown in Fig. 17, in this embodiment, the functions of a sharing adjustment rate setting unit 40a and a power command setting unit 50a are different from those of the first embodiment described above. Hereinafter, the same reference numerals are used to designate the same components as in the first embodiment, and the description is omitted, and the different components are mainly described.

[0065] When the battery system 1a is connected to the DC link 8, it is necessary to control the charging and discharging of the battery system 1 so that the bus voltage of the DC link 8 falls within a voltage range required by the power grid. For example, if the voltage of the DC link 8 rises due to the supply of power from the power system 2, the battery system 1a is charged with power corresponding to the voltage increase, thereby suppressing the voltage rise of the DC link 8. Conversely, if the voltage of the DC link 8 drops due to the supply of power to the power system 2, the battery system 1a is discharged with power corresponding to the voltage drop, thereby suppressing the voltage drop of the DC link 8.

[0066] Fig. 18 is a diagram showing the relationship between the individual power commands according to this embodiment and the bus voltage of the DC link 8. In Fig. 18, the horizontal axis represents power, and the vertical axis represents the differential voltage between the target voltage of the DC link 8 and the operating voltage of the DC link 8, and the relationship between the differential voltage and the individual power commands is indicated by a solid line. In FIG. 18, +Vm_max is, for example, the maximum allowable voltage for the target voltage of the DC link 8, and -Vm_max is, for example, the minimum allowable voltage for the target voltage of the DC link 8. In other words, Vm_max and -Vm_max respectively indicate the upper limit and lower limit of the allowable voltage range for the target voltage of the DC link 8. Here, the maximum allowable voltage and the minimum allowable voltage are merely examples and are not limited thereto. That is, they may be set appropriately depending on the operation of the battery system 1 and the like. Also, in FIG. 18, -Pmax indicates the upper limit charge power of the power conversion device 7' and +Pmax indicates the upper limit discharge power of the power conversion device 7' as examples, but are not limited thereto. That is, they may be set appropriately depending on the operation of the battery system 1 and the like. From FIG. 18, the relationship between the individual power command Pdiv and the differential voltage Vp is expressed by the following equation (3).

[0067] Vp = -a × Pdiv (3) where a=Vmax / Pmax

[0068] When the above equation (3) is converted into a derivation equation for Pdiv, the following equation (4) is obtained. Pdiv=-Vp / a (4)

[0069] As shown in Fig. 18, when the current differential voltage Vp = +ΔV1, the individual power command Pdiv is P1 (charging), and when the current differential voltage Vp = -ΔV2, the individual power command Pdiv is P2 (discharging). From Fig. 18, it can be seen that the individual power command Pdiv is set to a larger value as the operating voltage of the DC link 8 deviates from the target voltage. It can also be seen that when the slope a is increased, the individual power command decreases, and when the slope a is decreased, the individual power command increases. Therefore, in this embodiment, the slope a is changed according to the deterioration evaluation value, more specifically, the sharing adjustment rate α(i) calculated in the first embodiment, thereby performing charge / discharge control of each storage value according to the deterioration evaluation value.

[0070] In this embodiment, the sharing adjustment rate setting unit 40a calculates the slope a(i) by using the sharing adjustment rate α(i) of each storage battery in the following equation (5).

[0071] a(i)=a×{1 / α(i)} (5)

[0072] In equation (5), a(i) is the slope of the storage battery with identification information i, a is the default slope (a=Vmax / Pmax), and α(i) is the sharing adjustment rate of the storage battery with identification information i, and is calculated using equation (1) described in the first embodiment. As can be seen from equation (5), a smaller slope is set for an operating battery with a high degradation evaluation value (high health) than for an operating battery with a low degradation evaluation value.

[0073] After calculating the slope a(i) for each storage battery, the sharing adjustment rate setting unit 40a outputs slope information that associates the identification information of each storage battery with the slope to the data management unit 30. Time information, etc. may be added to the slope information.

[0074] The power command setting unit 50a calculates an individual power command Pdiv(i) for each operational battery using the gradient a(i) corresponding to each battery and the operating voltage (actually measured voltage) of the DC link 8. For the operating voltage of the DC link 8, it is possible to use information notified from the battery system 1, more specifically, the power conversion device 7′, for example. Specifically, the power command setting unit 50a acquires the slope a(i) of each storage battery stored in the memory unit 60, and calculates the individual power command Pdiv(i) of each storage battery by using the acquired slope a(i) and the differential voltage Vp between the operating voltage of the DC link 8 and the target voltage in the following equation (6).

[0075] Pdiv(i)=-Vp / a(i) (6)

[0076] When the power command setting unit 50a sets the individual power command Pdiv(i) for each operational storage battery, the power command setting unit 50a transmits the individual power command Pdiv(i) to the power conversion device 7' corresponding to each operational storage battery. As a result, in each operational storage battery, charging and discharging control according to the individual power command Pdiv(i) is performed.

[0077] For example, an example of the slope and individual power commands when the SOH(2) of battery 5b is higher than the SOH(1) of battery 5a is shown in comparison in Fig. 19. As shown in Fig. 19, the individual power commands Pc(2), Pd(2) of battery 5b are larger than those of battery 5a, so the charge / discharge current of battery 5b is larger than that of battery 5a, and the amplitude of the SOC is also larger than that of battery 5a.

[0078] In this way, when the battery system 1 is connected to the DC link 8, it is possible to set an individual power command for each storage battery based on the SOH using the slope information.

[0079] Third Embodiment Next, a power supply and demand system, a battery control system, a battery control method, and a program according to a third embodiment of the present disclosure will be described with reference to the drawings. For example, when control is performed to change the power sharing depending on the deterioration evaluation value of the storage battery 5 as in the first and second embodiments described above, it has been found that the median state of charge (SOC) varies over time between the storage batteries, as shown in Fig. 20. Fig. 20 is a diagram comparing the time progression of the SOC of a storage battery (e.g., storage battery 5a) with a relatively small sharing adjustment rate, in other words, a relatively low SOH (solid line), with the time progression of a storage battery (e.g., storage battery 5b) with a relatively large sharing adjustment rate, in other words, a relatively high SOH (dotted line). For example, the discharge current tends to be large and the charge current tends to be small for the storage battery 5b (e.g., a storage battery with a sharing adjustment rate of 1 or more), and the discharge current tends to be small and the charge current tends to be large for the storage battery 5a (e.g., a storage battery with a sharing adjustment rate of less than 1). Even when power sharing based on the degradation evaluation value is not performed as in the first and second embodiments, the variation in the central value of the charging rate among the storage batteries occurs to a certain extent, although the degree varies, due to individual differences between the storage batteries.

[0080] Furthermore, as illustrated in Figure 20, when there is variation in the median SOC value between storage batteries, the upper or lower limit value of the charging rate is more likely to reach the allowable upper or lower limit value of the battery system 1 than when there is no variation, which may shorten the life of the battery system 1. Therefore, the battery control system 10b according to this embodiment has a function for reducing the variation in the central SOC value between the storage batteries over time. In the following, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and the different components are mainly described.

[0081] Fig. 21 is a functional configuration diagram showing an example of functions of a battery control system 10b according to this embodiment. As shown in Fig. 21, the battery control system 10b of this embodiment is different from the first embodiment in that it includes an individual offset power setting unit 70 and in the method of setting an individual power command by a power command setting unit 50b.

[0082] 22 is a functional configuration diagram showing an example of functions included in the individual offset power setting unit 70. As shown in FIG. 22, the individual offset power setting unit 70 includes an individual average calculation unit 71, a total average calculation unit 72, and an offset calculation unit 73.

[0083] The individual average calculation unit 71 calculates an individual average charging rate for each storage battery, for example, by using charging rate data for each storage battery 5 in a predetermined period. For example, battery information (current data, voltage data, temperature data, abnormality detection data, etc.) of each storage battery 5a-5d is repeatedly transmitted from the battery system 1 to the battery control system 10b 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 (SOC data) for each storage battery in the predetermined period.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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. 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.

[0088] The power command setting unit 50b 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 (7).

[0089] Pdiv'(i)={Pall×(1 / N)×α(i)}+Ps(i) (7)

[0090] As a result, each operational storage battery is given an individual power command based on the deterioration evaluation value (SOH) and that suppresses SOC variations between the storage batteries over time, and charging and discharging of the power conversion device 7 is controlled based on this individual power command.

[0091] As described above, the battery control system 10b according to this embodiment includes an individual offset power setting unit 70 that calculates an individual offset power for correcting an individual power command, and the individual offset power setting unit 70 includes 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 in a predetermined period, an overall average calculation unit 72 that calculates an overall average charging rate that serves as a reference for the entire battery system, and 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. The power command setting unit 50b sets an individual power command for each operational storage battery using the individual offset power Ps(i) and sharing adjustment rate α(i) for each storage battery.

[0092] In this way, since the individual power command of each operational storage battery is set using the individual offset power Ps, it is possible to suppress the variation in the median SOC value between the storage batteries over time, for example, as shown in Fig. 23. This makes it possible to lengthen the time until the maximum and minimum charging rates of each operational storage battery reach the allowable upper and lower limits, and to extend the life of the entire battery system.

[0093] [Variation 3-1] In the present 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 as described in the second embodiment. For example, in the second embodiment, the individual power command Pdiv(i) calculated by the power command setting unit 50a may be corrected by the individual offset power Ps(i), and the corrected individual power command Pdiv'(i) may be given to each storage battery. That is, the individual power command Pdiv'(i) is given by the following equation (8).

[0094] Pdiv(i)=-Vp / a(i)+Ps(i) (8)

[0095] Moreover, correcting the individual power command Pdiv with the individual offset power Ps(i) corresponds to translating the power command characteristic along the X-axis as shown in Fig. 24. For this reason, for example, instead of the individual offset power Ps(i), the individual offset power setting unit 70 may output information on the intercept of the power command characteristic corresponding to the individual offset power Ps(i) to the data management unit 30. As a result, when the battery system 1 is connected to the DC link 8, the individual power command Pdiv'(i) may be calculated based on the information on the slope a(i) and the intercept b.

[0096] [Fourth embodiment] Next, a power supply and demand system, a battery control system, a battery control method, and a program according to a fourth embodiment of the present disclosure will be described with reference to the drawings. Each storage battery 5 constituting the battery system 1 is equipped with a power conversion device 7, a battery monitoring unit (BMU) that monitors the battery state, and the like, and these devices cause power loss. Since the amount of this power loss changes over time, the central value of the charge / discharge range of the battery system 1 as a whole gradually changes. For example, as shown in FIG. 25, in the early stages of operation, charging and discharging are performed around an SOC of 50%, whereas in the middle to late stages of operation, charging and discharging may be performed around an SOC of 50% or less. In this way, when the central value of the charge / discharge range of the battery system as a whole drops, the minimum SOC (SOCmin in FIG. 25) becomes more likely to reach the lower allowable limit of the storage battery, and the battery life may be shortened.

[0097] Therefore, the battery control system 10c according to this embodiment has a function for suppressing such a change in the central value of the SOC of the entire battery system over time. In the following, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and the different components are mainly described.

[0098] 26 is a functional configuration diagram showing an example of functions provided in a battery control system 10c according to this embodiment. As shown in FIG 26, the battery control system 10c according to this embodiment includes an overall offset power setting unit 80 and a system required power correction unit 90. 27 is a functional configuration diagram showing an example of functions included in the total offset power setting section 80. As shown in FIG. 27, the total offset power setting section 80 includes a total average calculation section 81 and an offset calculation section .

[0099] The overall average calculation unit 81 calculates the overall average charging rate of the battery system 1, for example, by using charging rate data of the battery system 1 during a predetermined period. For example, the overall average calculation unit 81 can calculate the overall average charging rate by a method similar to that of the third embodiment described above. That is, the average of the moving average values ​​calculated for each storage battery is calculated as the overall average charging rate. In addition, the maximum charging rate and the minimum charging rate during a predetermined period may be specified for the entire battery system 1, and the average value of these values ​​may be calculated as the overall average charging rate. The overall average charging rate can be calculated by statistically processing the charging rate data of each storage battery during a predetermined period and calculating the center value of the charging rates, and a known technology may be appropriately adopted as a specific method.

[0100] Note that the specific period and the like can be set appropriately depending on the operation of the battery system 1. For example, a simulation can be performed in advance, and the predetermined period can be set as a period during which the difference between the central value of the charging rate and the central value at the beginning of operation becomes equal to or greater than a predetermined value for the entire battery system.

[0101] The offset calculation unit 82 calculates an overall offset power for bringing the overall average charging rate of the battery system 1 closer to a target charging rate (e.g., 50%). For example, the offset calculation unit 82 calculates the deviation between the overall average charging rate and the target charging rate, and performs proportional-integral control on this deviation to calculate an overall offset power that makes the deviation zero. After calculating the total offset power Pg, the offset calculation unit 82 outputs the total offset power Pg to the data management unit 30. As a result, the total offset power Pg is stored in the storage unit 60, and the total offset power Pg is updated at predetermined intervals.

[0102] The system required power correction unit 90 corrects the system required power received from the grid monitoring system 6 using the total offset power Pg. For example, the system required power correction unit 90 reads out the total offset power Pg stored in the storage unit 60, and calculates the corrected system required power Pall' (=Pall+Pg) by adding the total offset power Pg to the system required power Pall. This process is performed, for example, every time the system required power is received from the grid monitoring system 6.

[0103] The system required power correction unit 90 outputs the corrected system required power Pall' to the power command setting unit 50c. The power command setting unit 50c acquires the sharing adjustment rate α(i) stored in the memory unit 60, and sets an individual power command Pdiv'(i) for the operating storage battery using the acquired sharing adjustment rate α(i) for each storage battery and the corrected system required power Pall'. For example, the individual power command Pdiv'(i) is given by the following equation (9).

[0104] Pdiv'(i)={Pall'×(1 / N)×α(i)} (9)

[0105] As a result, each operational storage battery is given an individual power command that is based on the SOH and that suppresses changes in the central value of the SOC of the entire battery system over time, and charging and discharging of the power conversion device 7 is controlled based on this individual power command.

[0106] As described above, the battery control system 10c according to this embodiment includes an overall offset power setting unit 80 that calculates an overall offset power Pg for correcting the system required power, and a system required power correction unit 90 that corrects the system required power Pall using the overall offset power Pg. The overall offset power setting unit 80 also includes an overall average calculation unit 81 that calculates an overall average charging rate, which is an average charging rate of the battery system 1, using charging rate data of the battery system 1 during a predetermined period, for example, and an offset calculation unit 82 that calculates an overall offset power for bringing the overall average charging rate closer to a predetermined reference charging rate. The power command setting unit 50c sets individual power commands for each operational storage battery using the sharing adjustment rate α(i) and the corrected system required power Pall'.

[0107] This makes it possible to suppress the change in the median value of the SOC of the entire battery system over time, which in turn makes it possible to lengthen the time until the maximum and minimum charging rates of the storage battery reach the allowable upper and lower limits, thereby extending the life of the entire battery system.

[0108] [Variation 4-1] In this embodiment, the total offset power is calculated using the total average charging rate of the battery system 1, but this is not limited to this. Fig. 28 shows a functional configuration diagram of a total offset power setting unit 80a according to a modified example. As shown in Fig. 28, the total offset power setting unit 80a includes a representative charging rate determination unit 83 and an offset calculation unit 84.

[0109] The representative charging rate determination unit 83 determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system 1 using charging rate data of the battery system 1 for a predetermined period. An example of the upper limit representative charging rate is the maximum charging rate of the battery system 1, and an example of the lower limit representative charging rate is the minimum charging rate of the battery system 1. The upper limit representative charging rate and the lower limit representative charging rate are not limited to these. 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. The offset calculation unit 84 calculates the difference between the upper limit representative charging rate and the allowable upper limit of the charging rate (upper limit difference) and the difference between the lower limit representative charging rate and the allowable lower limit of the charging rate (lower limit difference), and calculates the total offset power for bringing the deviation between the upper limit difference and the lower limit difference closer to zero. For example, the total offset power is calculated by performing proportional-integral control on the deviation.

[0110] According to the entire offset power setting unit 80a of the modified example 4-1, it is possible to control the operational fluctuation range of the charging rate of the entire battery system to be 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.

[0111] The battery control system 10c according to this embodiment and modification 4-1 can also be applied to the case where the battery system 1 is connected to the DC link 8, as in the second embodiment. In this case, however, the system required power correction unit 90 is omitted, and the total offset power calculated by the total offset power setting unit 80 is provided to the AC / DC converter 9, which performs power control based on the total offset power.

[0112] Furthermore, the battery control system 10c according to the fourth embodiment and the modified example 4-1 described above may include the individual offset power setting unit 70 according to the third embodiment described above. In this way, by further adding a configuration for correcting an individual power command for each operational storage battery using an individual offset, it is possible to suppress deviation over time of the central SOC value of the entire battery system and to suppress deviation of the central SOC value between the storage batteries constituting the battery system 1.

[0113] 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 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. Furthermore, the processing flow described in the above embodiment is also one example, and unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged, without departing from the spirit of the present disclosure.

[0114] For example, in the above-described embodiments and modifications, the battery control systems 10, 10a, 10b, and 10c are described as including 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 systems 10, 10a, 10b, and 10c, and may be configured to enable data to be read from and written to the storage unit via a network, for example.

[0115] The power supply and demand system, the battery control system, the battery control method, and the program described in the above-described embodiments can be understood, for example, as follows.

[0116] A battery control system (10) according to a first aspect of the present disclosure is a battery control system applied to a battery system (1) having a plurality of storage batteries (5), and includes a degradation state evaluation unit (20) that sequentially selects storage batteries to be evaluated for their degradation state, and calculates a degradation evaluation value relating to the degradation state of the storage battery to be evaluated using a voltage value or a current value when charging and discharging of the storage battery to be evaluated according to a predetermined charge and discharge pattern, a data management unit (30) that associates identification information of the storage battery with the degradation evaluation value and stores them in a memory unit (60), a sharing adjustment rate setting unit (40) that sets a sharing adjustment rate using the degradation evaluation values ​​of the plurality of storage batteries, and a power command setting unit (50) that uses the sharing adjustment rate to set individual power commands for each operational storage battery, which is a storage battery other than the storage battery to be evaluated.

[0117] According to the above aspect, it is possible to perform a degradation state evaluation for some of the storage batteries constituting the battery system, and in parallel with this, it is possible to perform charge / discharge control for some or all of the remaining storage batteries as operational storage batteries based on the system required power from a higher-level system such as a grid power. In this case, power sharing is performed for the operational storage batteries based on the degradation evaluation value. This makes it possible to suppress the variation in the degradation evaluation value between the storage batteries, and to extend the life of the battery system as a whole.

[0118] A battery control system (10) according to a second aspect of the present disclosure, in the above-mentioned first aspect, includes a recovery control unit (23) that controls the storage battery to be evaluated so as to bring the charge state of the storage battery to be evaluated closer to the charge state of the operational storage battery after charge / discharge control based on the charge / discharge pattern is completed, and recovers the storage battery to be evaluated as an operational storage battery when the charge state of the storage battery to be evaluated and the charge state of the operational storage battery satisfy predetermined conditions.

[0119] According to the above aspect, the storage battery to be evaluated can be quickly returned to the supply and demand of power as an operational storage battery after the evaluation of the deterioration state is completed. Examples of parameters indicating the charging state include a charging rate and a parameter related to a cell voltage.

[0120] In a battery control system (10) according to a third aspect of the present disclosure, in the first or second aspect described above, the sharing adjustment rate setting unit (40) calculates a target deterioration evaluation value using a deterioration evaluation value of each of the storage batteries that constitute the battery system, and sets a sharing adjustment rate for each of the storage batteries such that the deterioration evaluation value of each of the storage batteries approaches the target deterioration evaluation value.

[0121] According to the above aspect, it is possible to gradually bring the degradation evaluation value of each storage battery constituting the battery system closer to the target degradation evaluation value, thereby reducing the variation in the degradation evaluation value of each storage battery.

[0122] A battery control system (10) according to a fourth aspect of the present disclosure, in any of the first to third aspects above, includes an individual offset power setting unit (70) that calculates an individual offset power for correcting the individual power command, and the individual offset power setting unit includes 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 in a predetermined period, an overall average calculation unit (72) that calculates an overall average charging rate that serves as a reference for the entire battery system, and 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 the power command setting unit (50) sets individual power commands for each operational storage battery, which is a storage battery other than the storage battery to be evaluated, using the individual offset power for each storage battery and the sharing adjustment rate.

[0123] According to the above aspect, it is possible to make the average value of the charging rate of each storage battery closer to the overall average charging rate. This makes it possible to suppress the variation in the central value of the SOC among the storage batteries over time. As a result, it is possible to lengthen the time until the maximum and minimum values ​​of the charging rate of each operating storage battery reach the allowable upper and lower limits, and it is possible to further extend the life of the entire battery system.

[0124] A battery control system (10) according to a fifth aspect of the present disclosure, in any of the first to fourth aspects above, includes an overall offset power setting unit (80) that calculates an overall offset power for correcting the system required power, and a system required power correction unit (90) that corrects the system required power of the battery system using the overall offset power, and the overall offset power setting unit (80) includes an overall average calculation unit (81) that calculates an overall average charging rate, which is the average charging rate of the battery system, using charging rate data of the battery system (1) during a predetermined period, and an offset calculation unit (82) that calculates an overall offset power for approximating the overall average charging rate to a predetermined reference charging rate.

[0125] According to the above aspect, an overall average charging rate, which is an average charging rate of the battery system in a predetermined period, is calculated, an overall offset power is calculated to bring the calculated overall average charging rate closer to a predetermined reference charging rate, and the calculated overall offset power is used to correct the system required power. Then, an individual power command for each operating storage battery is set based on the corrected system required power. This makes it possible to suppress the change in the central value of the charging rate of the entire battery system over time, which in turn makes it possible to lengthen the time until the maximum and minimum charging rates of the storage batteries reach the allowable upper and lower limits, thereby further extending the life of the entire battery system.

[0126] A battery control system (10) according to a sixth aspect of the present disclosure, in any one of the first to fourth aspects described above, includes an overall offset power setting unit (80a) that calculates an overall offset power for correcting the system required power, and a system required power correction unit (90) that corrects the system required power of the battery system using the overall offset power, and the overall offset power setting unit (80a) includes a representative charging rate determination unit (83) 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 (1) for a predetermined period, and an offset calculation unit (84) that calculates an overall offset power for bringing a difference between the upper limit representative charging rate and an allowable upper limit value of the charging rate and the difference between the lower limit representative charging rate and an allowable lower limit value of the charging rate closer to zero.

[0127] According to the above aspect, an upper representative charging rate that is a representative value of an upper limit side charging rate in the battery system and a lower representative charging rate that is a representative value of a lower limit side charging rate in the battery system are determined, and an overall offset power is calculated to bring the difference between the upper representative charging rate and the allowable upper limit of the charging rate and the difference between the lower representative charging rate and the allowable lower limit of the charging rate closer to zero. Then, the system required power is corrected using the calculated overall offset power, and individual power commands for each operating storage battery are set based on the corrected system required power. This makes it possible to suppress the change in the central value of the charging rate of the entire battery system over time. As a result, it is possible to lengthen the time until the maximum and minimum charging rates of the storage batteries reach the allowable upper and lower limits, and it is possible to further extend the life of the entire battery system. In addition, by using the maximum and minimum charging rates, it is possible to evenly arrange the charging and discharging range of the entire battery system between the allowable upper and lower limits, for example, even in cases where the charging and discharging control of the charging rates of some storage batteries is performed near the allowable upper and lower limits.

[0128] An electric power supply and demand system (100, 100a) according to a seventh aspect of the present disclosure includes a battery system (1, 1a) including a plurality of storage batteries, and a battery control system (10, 10a, 10b, 10c) according to any one of the first to sixth aspects.

[0129] A battery control method according to an eighth aspect of the present disclosure is a battery control method applied to a battery system including a plurality of storage batteries, and a computer executes the following steps: a degradation state evaluation process for sequentially selecting storage batteries to be evaluated for their degradation state, and calculating a degradation evaluation value related to the degradation state of the storage battery to be evaluated using a voltage value or a current value when charging and discharging of the storage battery to be evaluated according to a predetermined charge and discharge pattern; a data management process for associating identification information of the storage battery with the degradation evaluation value and storing them in a memory unit; a sharing adjustment rate setting process for setting a sharing adjustment rate using the degradation evaluation values ​​of the plurality of storage batteries; and a power command setting process for using the sharing adjustment rate to set individual power commands for each operational storage battery, which is a storage battery other than the storage battery to be evaluated.

[0130] A battery control method according to a ninth aspect of the present disclosure is a program for causing a computer to function as the battery control system according to any one of the first to sixth aspects. [Explanation of symbols]

[0131] 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, 10b, 10c: Battery control system 11: CPU 12: Main memory 13:Secondary storage device 14: Communication interface 15: Input device 16: Display 20: Deterioration state evaluation section 21: Selection Department 22: Measurement execution unit 23:Return control section 24: Evaluation value calculation unit 30: Data Management Department 40,40a: Sharing adjustment rate setting section 50,50a,50b,50c: Power command setting section 60: Storage section 70: Individual offset power setting section 71:Individual average calculation section 72: Overall average calculation section 73: Offset calculation section 80, 80a: Overall offset power setting section 81: Overall average calculation section 82: Offset calculation section 83:Representative charging rate determination section 84: Offset calculation section 90: System required power correction 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, a degradation state evaluation unit that sequentially selects storage batteries to be evaluated for a degradation state, and calculates a degradation evaluation value related to the degradation state of the storage battery to be evaluated using a voltage value or a current value when charging and discharging the storage battery to be evaluated according to a preset charge and discharge pattern; a data management unit that stores the identification information of the storage battery and a deterioration evaluation value in a storage unit in association with each other; a sharing adjustment rate setting unit that sets a sharing adjustment rate using deterioration evaluation values ​​of the plurality of storage batteries; a power command setting unit that sets an individual power command for each of the operational storage batteries that is a storage battery other than the evaluation target, using the sharing adjustment rate; A battery control system comprising:

2. The degradation state evaluation unit is The battery control system of claim 1 further comprising a recovery control unit that controls the storage battery to be evaluated so as to bring the charge state of the storage battery to be evaluated closer to the charge state of the operational storage battery after charge and discharge control based on the charge and discharge pattern is completed, and recovers the storage battery to be evaluated as an operational storage battery when the charge state of the storage battery to be evaluated and the charge state of the operational storage battery satisfy predetermined conditions.

3. The battery control system of claim 1, wherein the sharing adjustment rate setting unit calculates a target deterioration evaluation value using the deterioration evaluation value of each of the storage batteries that constitute the battery system, and sets a sharing adjustment rate for each of the storage batteries such that the deterioration evaluation value of each of the storage batteries approaches the target deterioration evaluation value.

4. an individual offset power setting unit that calculates an individual offset power for correcting the individual power command; The individual offset power setting unit 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 overall average calculation unit that calculates an overall average charging rate that is a reference for the entire battery system; 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; Equipped with The battery control system according to claim 1 , wherein the power command setting unit uses the individual offset power for each of the storage batteries and the sharing adjustment rate to set individual power commands for each of the operational storage batteries that are not the storage batteries to be evaluated.

5. an overall offset power setting unit that calculates an overall offset power for correcting the system required power; a system required power correction unit that corrects a system required power of the battery system using the total offset power; Equipped with The entire offset power setting unit an overall average calculation unit that calculates an overall average charging rate, which is an average charging rate of the battery system, using charging rate data of the battery system for a predetermined period; an offset calculation unit that calculates an overall offset power for making the overall average charging rate closer to a predetermined reference charging rate; The battery control system according to claim 1 .

6. an overall offset power setting unit that calculates an overall offset power for correcting the system required power; a system required power correction unit that corrects a system required power of the battery system using the total offset power; Equipped with The entire offset power setting unit a representative 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 during a predetermined period; an offset calculation unit that calculates a total offset power for bringing a difference between a difference between the upper limit representative charging rate and a permissible upper limit value of the charging rate and a difference between the lower limit representative charging rate and a permissible lower limit value of the charging rate closer to zero; The battery control system according to claim 1 .

7. A battery system including a plurality of storage batteries; A battery control system according to any one of claims 1 to 6. An electricity supply and demand system comprising:

8. A battery control method applied to a battery system including a plurality of storage batteries, a degradation state evaluation step of sequentially selecting storage batteries to be evaluated for a degradation state, and calculating a degradation evaluation value relating to the degradation state of the storage battery to be evaluated using a voltage value or a current value when the charging and discharging of the storage battery to be evaluated is controlled according to a preset charging and discharging pattern; a data management step of storing the identification information of the storage battery and a deterioration evaluation value in a storage unit in association with each other; a sharing adjustment rate setting step of setting a sharing adjustment rate using deterioration evaluation values ​​of the plurality of storage batteries; a power command setting step of setting an individual power command for each operational storage battery that is a storage battery other than the evaluation target, using the sharing adjustment rate; The computer executes the battery control method.

9. A program for causing a computer to function as the battery control system according to any one of claims 1 to 6.

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