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

Abstract

The present invention extends the life of a battery system as a whole without reducing the operation efficiency of the battery system. A battery control system (10) comprises: a deterioration state evaluation unit (20) that sequentially selects a to-be-evaluated storage battery that will be evaluated in terms of the deterioration state, and calculates a deterioration evaluation value, which relates to the deterioration state of the to-be-evaluated storage battery, by using a voltage value or a current value from when charging / discharging of the to-be-evaluated storage battery is controlled in accordance with a preset charge / discharge pattern; a data management unit (30) that associates identification information of storage batteries and the deterioration evaluation value, and stores the same in a storage unit (60); an apportionment adjustment rate setting unit (40) that sets an apportionment adjustment rate by using the deterioration evaluation values of a plurality of the storage batteries; and a power command setting unit (50) that uses the apportionment adjustment rate to set an individual power command for each operating storage battery, which are the storage batteries other than the to-be-evaluated storage battery.

Description

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

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

[0002] In a battery system including multiple storage batteries, it has been proposed to monitor the degradation state of each storage battery and to perform control to suppress the progression of the degradation state of a storage battery that is in an advanced state of degradation. For example, Patent Document 1 discloses that the charge / discharge of each storage battery is controlled so that the degradation states of the multiple storage batteries are equivalent, focusing on the degradation state of the storage battery determined based on the state of charge (SOC: State of Charge) of the storage battery and the temperature state. More specifically, Patent Document 1 discloses that for a storage battery in an advanced state of degradation, control is performed to increase the limit on the maximum current value and the limit on the end voltage of charging / discharging in order to suppress the progression of the degradation state of the storage battery.

[0003] Patent No. 5932190

[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 determine the current degree of deterioration, and periodically measuring the full charge capacity of the storage battery and correcting the estimated degree of deterioration using the measured value. In this way, Patent Document 1 discloses a method for periodically measuring the full charge capacity of the storage battery and correcting the degree of deterioration, thereby making it possible to obtain a relatively accurate degree of deterioration.

[0005] However, the periodic measurement of the full charge capacity is generally performed while the battery system is stopped, which may reduce the operational efficiency of the battery system.

[0006] The present disclosure has been made in consideration of these circumstances, and aims to provide a power supply and demand system, a battery control system, a battery control method, and a program that can extend the life of the entire battery system without reducing the operational efficiency of the battery system.

[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 the association 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, the battery control method including a degradation state evaluation process in which storage batteries to be evaluated are sequentially selected to be evaluated for their degradation state, and a degradation evaluation value relating to the degradation state of the storage battery to be evaluated is calculated 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 predetermined charge and discharge pattern method; a data management process in which identification information of the storage battery is associated with the degradation evaluation value and stored in a memory unit; a sharing adjustment rate setting process in which a sharing adjustment rate is set using the degradation evaluation values ​​of the plurality of storage batteries; and a power command setting process in which individual power commands are set 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.

[0011] The life of the entire battery system can be extended without reducing the operational efficiency of the battery system.

[0012] 6 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 7 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 8 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 9 is an enlarged view of the state of charge when adjustment charging is performed according to the first embodiment of the present disclosure. FIG. 1 is a flowchart showing an example of the procedure of an individual power command setting process executed by the battery control system according to the first embodiment of the present disclosure. FIG. 2 is a diagram for explaining the effect of the battery control system according to the first embodiment of the present disclosure. FIG. 3 is a diagram showing a schematic configuration of a power supply and demand system according to a second embodiment of the present disclosure. FIG. 4 is a functional configuration diagram showing an example of functions included in the battery control system according to the second embodiment of the present disclosure. FIG. 5 is a diagram showing the relationship between an individual power command and a DC link bus voltage according to the second embodiment of the present disclosure. FIG. 6 is a diagram showing an example of the relationship between the slope of storage batteries with different SOHs and the individual power commands. FIG. 7 is a diagram for explaining that variation occurs in the central value of the charging rate between storage batteries over time. FIG. 8 is a functional configuration diagram showing an example of functions included in the battery control system according to the third embodiment of the present disclosure. FIG. 9 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. FIG. 10 is a diagram for explaining the effect of the battery control system according to the third embodiment of the present disclosure.FIG. 10 is a diagram for explaining individual offset power when a battery system is connected to a DC link. FIG. 11 is a diagram for explaining that the center of SOC of the entire battery system tends to shift over time. FIG. 12 is a functional configuration diagram showing an example of functions provided in a battery control system according to a fourth embodiment of the present disclosure. FIG. 13 is a functional configuration diagram showing an example of functions provided in an overall offset power setting unit according to the fourth embodiment of the present disclosure. FIG. 14 is a diagram showing a functional configuration diagram of an overall offset power setting unit according to a modified example.

[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. Fig. 1 is a diagram showing a schematic configuration of a power supply and demand system 100 according to an embodiment of the present disclosure. As shown in Fig. 1, the 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 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 multiple storage batteries 5 (5a to 5d). While FIG. 1 illustrates an example in which four storage batteries 5 are included, 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 there is no need to distinguish between them, they will be simply referred to as storage batteries 5. The same applies to other configurations.

[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. 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 this 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 batteries 5 by operating based on, for example, individual power commands provided 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 grid into DC power and outputs it to the storage batteries 5. During discharging, the power converter 7 converts DC power from the storage batteries 5 into AC power and supplies it to the power grid 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 exchange information. The battery control system 10 may be a cloud server or a local system installed at the installation location of the battery system 1. The battery control system 10 is 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, a battery control system 10 according to this embodiment will be described. FIG. 2 is a diagram showing an example of the 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 storage device 12 is composed of writable memory such as cache memory, RAM (Random Access Memory), etc., and is used as a work area for reading execution programs of the CPU 11 and writing processing data by the execution programs. The secondary storage device 13 is a non-transitory computer-readable storage medium. Examples of the secondary storage device 13 include magnetic disks such as HDDs (Hard Disk Drives), magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories such as SSDs (Solid State Drives).

[0020] 3 is a functional configuration diagram showing an example of functions of the battery control system 10 according to this embodiment. The battery control system 10 evaluates the degradation state of each storage battery 5 while the battery system 1 is connected to the power grid 2, and controls the charging and discharging of each storage battery 5 using the evaluation results 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 the 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 operations to realize the various functions. 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 while 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, and when a command to start the degradation state evaluation is input by the user. The start condition may be set as a combination of these. 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 illustrating 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 recovery control unit 23, and an evaluation value calculation unit 24. The selection unit 21 sequentially selects storage batteries 5 to be evaluated during degradation state evaluation. Specifically, during degradation state evaluation, the selection unit 21 selects one or more storage batteries 5 to be evaluated according to a predetermined algorithm. Then, when the measurement execution unit 22 (described later) finishes evaluating the degradation state of the storage batteries 5 selected as the evaluation targets, the selection unit 21 selects one or more storage batteries 5 to be evaluated next as the evaluation targets. The selection unit 21 repeats the selection until all storage batteries 5a to 5d included in the battery system 1 have been selected as evaluation targets. In this embodiment, for convenience of explanation, a case where the selection is performed sequentially in the order of 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 in accordance with 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 in accordance with the 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 in accordance with the charging and discharging pattern, thereby realizing charging and discharging in accordance with the charging and discharging pattern.

[0025] The charge / discharge pattern may include, for example, a charge pattern for charging to a fully charged state and a discharge pattern for discharging to a lower charge limit state. The charge pattern may also include an adjusted charge pattern for gradually or continuously changing the charging current value near the fully charged state. By including such an adjusted charge pattern, the storage battery 5 can be brought closer to a fully charged state than when charging with only a constant current (e.g., 1 C).

[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 such an adjusted discharge pattern, the storage battery 5 can be brought closer to the lower limit of the charge amount compared to discharging at a constant current (e.g., 1 C).

[0027] Fig. 5 is a diagram showing an example of the change in state of charge (SOC) when charge / discharge control according to this embodiment is performed. Fig. 6 is a diagram showing an example of the change in battery voltage when charge / discharge control is performed using the same charge / discharge pattern as Fig. 5. In Figs. 5 and 6, the solid lines show an example of the change in the battery voltage of the storage battery under evaluation, and the dotted lines show an example of the change in the battery voltage of any storage battery other than the storage battery under evaluation (operational storage battery).

[0028] FIG. 7 is an enlarged view of the state of charge shown in FIG. 6 during conditioning charging. FIG. 7 illustrates a case where the current value is changed in a stepwise manner during conditioning charging. As shown in FIG. 7, during conditioning charging, it is preferable to gradually reduce the charging current value so that the battery voltage (open circuit voltage) when the charging current is stopped approaches the value of 100% SOC (fully charged state) as close as possible. While an example of changing the charging current in a stepwise manner is shown here, this is not limiting. For example, if the power conversion device 7 can charge while maintaining the maximum battery voltage of the storage battery 5, 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, the charging may be switched to CV charging to continue charging to full charge while avoiding an overvoltage charging state.

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

[0030] FIG. 8 is an enlarged view of the regulated discharge shown in FIG. 6 . FIG. 8 illustrates an example in which the current value is changed in a stepwise manner during regulated discharge. As shown in FIG. 8 , during regulated discharge, it is preferable to gradually reduce the discharge current value so that the battery voltage (open circuit voltage) when the discharge current is stopped approaches the value at an SOC of 0% as closely as possible. While an example in which the discharge current is changed in a stepwise manner is shown here, CC-CV discharge may also be used if the power conversion device 7 can discharge while maintaining the minimum battery voltage of the storage battery 5. 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 discharge may be switched to CV and continue down to the minimum battery voltage. The battery voltage (open circuit voltage) when the discharge current is stopped is preferably a value of 0% SOC, but may be other values. For example, if the SOC is 20% and a capacity test is performed for 80% SOC from 100% to 20%, the full charge capacity of the test result can be converted to the result of a capacity test for 100% SOC by multiplying it by 100% / 80% (= 1.25).

[0031] 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 execution unit 22 finishes measuring, in other words, after the charge / discharge control based on the predetermined charge / discharge pattern is completed, the recovery control unit 23 controls the charge / discharge of the storage battery under evaluation (e.g., 5a) so as to bring the state of charge of the storage battery under evaluation closer to the state of charge of the operational storage batteries (e.g., 5b-5d). Then, when the state of charge of the storage battery under evaluation (e.g., 5a) and the state of charge of the operational storage batteries (e.g., 5b-5d) satisfy predetermined conditions, the recovery control unit 23 recovers the storage battery under evaluation as an operational storage battery (see the recovery process in Figures 5 and 6). For example, the recovery control unit 23 may recover the storage battery under evaluation as an operational storage battery when the difference between the average cell voltage of the storage battery under evaluation and the average value of the average cell voltages of the operational storage batteries falls within a predetermined range. Instead of the average cell voltage, the charge rate may be used.

[0033] The evaluation value calculation unit 24 calculates a degradation evaluation value that evaluates 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 indicating a decrease in the current full charge capacity relative to the initial full charge capacity of the storage battery 5. One example is the SOH (State of Health). The SOH is the ratio of the latest (current) full charge capacity to the initial full charge capacity (the capacity of an undegraded battery). In other words, the SOH is a value obtained by normalizing the latest (current) full charge capacity [Ah] by a common battery capacity [Ah] (e.g., the maximum full charge capacity at the time of battery manufacture). The evaluation value calculation unit 24 calculates the latest full charge capacity (Ah) by, for example, integrating the current values ​​when the storage battery 5 to be evaluated is changed from a fully charged state to a lower charge limit state, or from the lower charge limit state to a fully charged state. Then, the SOH is calculated, for example, by dividing the latest full charge capacity by the full charge capacity at the start (initial) of operation of the battery system 1. In the process of calculating the latest full charge capacity, corrections may be made based on differences in test conditions (rate, temperature, etc.). The method for evaluating the degradation state of a battery is not limited to the above example, and for example, any known technique for evaluating the degradation state of a battery can be appropriately adopted.

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

[0036] The data management unit 30 (see FIG. 3 ) stores, for example, the degradation assessment information acquired from the degradation state assessment unit 20 in the storage unit 60. The data management unit 30 stores in the storage unit 60 the sharing adjustment rates of the storage batteries 5 a to 5 d calculated by the sharing adjustment rate setting unit 40 (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 to 5d based on the deterioration evaluation value (SOH) of each of the storage batteries 5a to 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 to 5d that constitute 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 to 5d closer to this target deterioration evaluation value. The target deterioration evaluation value is, for example, the average value of the deterioration evaluation values ​​of the storage batteries 5a to 5d.

[0038] As a result, a larger power sharing adjustment rate is set for a storage battery with a high degradation evaluation value (for example, a high SOH) than for a storage battery with a low degradation evaluation value. A storage battery 5 with a high power 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 power sharing adjustment rate. That is, during charging, a storage battery with a high power sharing adjustment rate charges more power than a storage battery with a low power sharing adjustment rate, and during discharging, a storage battery with a high power sharing adjustment rate discharges more power than a storage battery with a low power sharing adjustment rate.

[0039] For example, the sharing adjustment rate setting unit 40 calculates the sharing adjustment rate α(i) using a target degradation 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 degradation evaluation value SOHave and the SOH(i) of each storage battery 5. As an example, the sharing adjustment rate α(i) is calculated using the following equation (1).

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

[0041] In the above formula (1), i indicates the 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 equation (1), K is the adjustment gain, and the larger this adjustment gain K is, the shorter the time it takes for the variation in the degradation evaluation value to fall within a predetermined range. The adjustment gain K is a value equal to or greater than zero, and its upper limit is set within a range in which the sum of the individual power commands assigned to the operating storage batteries does not exceed the system required power. When the adjustment gain K is set to zero, the allocation adjustment rate for each of the storage batteries 5a to 5d is all 1, and in this case, there is no increase or decrease in the power allocation according to the SOH(i). In other words, the system required power is allocated equally to each storage battery.

[0044] For example, when a predetermined 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, thereby calculating degradation evaluation values ​​for all of the storage batteries 5 a to 5 d, and degradation evaluation information including the degradation evaluation values ​​for these storage batteries 5 a to 5 d is stored in the storage unit 60. 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 also 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 obtained from the grid monitoring system 6. Here, the operational battery is an operable battery, in other words, a battery capable of charge / discharge control in response to the system required power Pall. In other words, the batteries for which degradation is evaluated by the degradation state evaluation unit 20 described above are excluded from the operational batteries.

[0047] The power command setting unit 50 acquires the sharing adjustment rate α(i) of each operating storage battery stored in the memory unit 60, and calculates the individual power command for each operating 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 operational batteries. For example, when the degradation state evaluation unit 20 has not performed the degradation state evaluation, the batteries 5a to 5d may be operational batteries, and when the degradation state evaluation is being performed, batteries other than those being evaluated may be operational batteries.

[0050] As can be seen from equation (2), a larger individual power command 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. After allocating an individual power command Pdiv(i) to each operating battery, the power command setting unit 50 transmits the individual power command Pdiv(i) to the power conversion device 7 corresponding to each operating battery. As a result, charge and discharge control according to the individual power command Pdiv is performed in each operating battery.

[0051] For example, when the SOH(2) of battery 5b is higher than the SOH(1) of battery 5a, i.e., SOH(1)<SOH(2), and the sharing adjustment rate α(1) of battery 5a is set to 0.8 and the sharing adjustment rate α(2) of battery 5b is set to 1.2 as shown in FIG. 9, examples of the individual power commands, charge / discharge currents, and SOCs are shown in FIGS. 10 to 12, respectively. In FIGS. 10 to 12, the solid lines represent battery 5a and the dashed lines represent battery 5b. As shown in FIGS. 10 to 12, the individual power command of battery 5b is larger than that of battery 5a, and therefore 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.

[0052] Next, the operation of the battery control system 10 according to this embodiment will be described. Fig. 13 is a flowchart showing an example of the procedure for the degradation state evaluation process executed by the battery control system 10 according to this embodiment. The degradation state evaluation process described below is started when a preset condition for starting the degradation state evaluation is satisfied. For convenience of explanation, the following description will be given taking as an example a case where the degradation state evaluation is performed on the storage batteries 5a, 5b, 5c, and 5d in that order.

[0053] First, the battery control system 10 selects a storage battery 5a to be evaluated for its deterioration state (SA1), controls the charging and discharging of the storage battery 5a to be evaluated according to a predetermined charging and discharging pattern, and obtains battery information such as the voltage value, current value, and temperature 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 being evaluated is completed, a degradation evaluation value is calculated from the acquired battery information (SA3), and the identification information "#1" of the storage battery 5a being evaluated is associated with the degradation evaluation value and stored in internal memory (SA4). Next, a restoration process is performed (SA5). In the restoration process, the charge / discharge of the storage battery 5a being evaluated is controlled so that the charging rate of the storage battery 5a being evaluated approaches the charging rates of the operational batteries 5b to 5d. Then, when the charging rate of the storage battery 5a being evaluated satisfies a predetermined condition defined in relation to the charging rates of the operational batteries, the storage battery 5a being evaluated is restored as an operational battery.

[0055] Next, the system determines whether all of the storage batteries 5a to 5d have been selected as evaluation targets (SA6). In this case, because none of the storage batteries 5a to 5d have been selected (SA6: NO), the system returns to step SA1 and selects the unselected storage battery 5b as the evaluation target. Then, a degradation state evaluation is performed for the storage battery 5b. If the storage battery 5b has been selected as the evaluation target, the storage batteries 5a, 5c, and 5d are the operational storage batteries. The same process is performed for the storage batteries 5c and 5d. If it is determined in step SA6 that all of the storage batteries 5a to 5d have been selected as evaluation targets (SA6: YES), degradation evaluation information associating the identification information #1 to #4 of each storage battery 5a to 5d with its degradation evaluation value is output (SA7), and the process ends. This causes the degradation evaluation values ​​of each storage battery 5a to 5d to be 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, for example, a sharing adjustment rate setting process. 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 to 5d and stored in the memory unit 60. As a result, the latest sharing adjustment rate for each storage battery 5a to 5d is stored in the memory unit 60, and the sharing adjustment rate is updated.

[0057] Next, the 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 for the individual power command setting process. This process starts when operation of the battery system 1 is started and ends when operation is completed.

[0058] First, the battery control system 10 obtains the sharing adjustment rate α(i) for each of the storage batteries 5a to 5d from the storage unit 60 (SB1). Next, it determines whether a degradation state evaluation is in progress (SB2). If a degradation state evaluation is in progress (SB2: YES), the system identifies operational batteries excluding the battery being evaluated (SB3). For example, if the storage battery 5a is selected as the battery being evaluated, the system identifies the storage batteries 5b to 5d as operational batteries. On the other hand, if a degradation state evaluation is not in progress (SB2: NO), the system identifies the storage batteries 5a to 5d as operational batteries.

[0059] Next, for each operating battery, an individual power command is set using the sharing adjustment rate α(i) (SB4), and each individual power command is sent to each operating battery (SB5). This enables charge / discharge control that reflects the degradation evaluation value (e.g., SOH(i)) of each operating battery. Next, it is determined whether or not control of the battery system 1 has ended (SB6). If not (SB6: NO), the process returns to step SB2 and repeats the subsequent steps. On the other hand, if control has ended (SB6: YES), the 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 voltage values ​​or current values ​​when charging and discharging of the storage battery to be evaluated 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 memory unit 60. As a result, the memory unit 60 stores the degradation evaluation values ​​of the storage batteries 5a to 5d, and the degradation evaluation values ​​in the memory unit 60 are updated each 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 an individual power command for each operational storage battery using the sharing adjustment rate α(i). This makes it possible to operate operational storage batteries that are not being evaluated while evaluating the deterioration state. In this case, the operational storage batteries are controlled based on individual power commands that are set using the sharing adjustment rate α(i) calculated based on the respective deterioration evaluation values. This makes it possible to suppress variations in deterioration evaluation values ​​(SOH) between the storage batteries and extend the life of the entire battery system.

[0062] FIG. 15 is a diagram illustrating the effects of the battery control system 10 according to the first embodiment of the present disclosure. FIG. 15 illustrates an example of battery life compared between when the battery control system 10 according to the present embodiment is applied and when it is not applied. As shown in FIG. 15 , without control, the same individual power command is given to the storage batteries regardless of their SOH, so that the storage batteries with a low SOH in the initial state reach the end of their life first. On the other hand, when the battery control system 10 according to the present embodiment is applied, more individual power commands are given to the storage batteries with a high SOH, and relatively fewer individual power commands are given to the storage batteries with a low SOH. This makes it possible to gradually reduce the variation in SOH among the storage batteries. This particularly extends the life of the storage batteries with a low SOH in the initial state, thereby extending the life of the entire battery system, as shown in FIG. 15 .

[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 the battery system 1 is connected to the AC link 4 via this 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 the DC link 8 via a power conversion device 7′ (7a′ to 7d′) that is a DC / DC converter. The DC link 8 and the substation 3 are connected via an AC / DC converter 9.

[0064] 17 is a functional configuration diagram showing an example of functions provided in a battery control system 10a according to this embodiment. As shown in FIG. 17, in this embodiment, the functions of the sharing adjustment rate setting unit 40a and the power command setting unit 50a are different from those of the first embodiment described above. Hereinafter, components common to the first embodiment will be assigned the same reference numerals and description thereof will be omitted, and different components will be 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, when the voltage of the DC link 8 rises due to the supply of power from the power grid 2, the battery system 1a is charged with power corresponding to the voltage rise, thereby suppressing the voltage rise of the DC link 8. Conversely, when the voltage of the DC link 8 drops due to the supply of power to the power grid 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 and the bus voltage of the DC link 8 according to this embodiment. In FIG. 18 , the horizontal axis represents power, 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 represents, for example, the maximum allowable voltage relative to the target voltage of the DC link 8, and −Vm_max represents, for example, the minimum allowable voltage relative to the target voltage of the DC link 8. In other words, Vm_max and −Vm_max represent the upper and lower limits, respectively, of the allowable voltage range relative to the target voltage of the DC link 8. Here, the allowable maximum voltage and the allowable minimum voltage are merely examples and are not limited thereto. In other words, they may be set appropriately depending on the operation of the battery system 1, etc. In FIG. 18 , −Pmax represents the upper limit power charge of the power conversion device 7′, and +Pmax represents the upper limit power discharge of the power conversion device 7′, as an example, but are not limited thereto. In other words, they may be set appropriately depending on the operation of the battery system 1, etc. 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 x Pdiv (3) where a = Vmax / Pmax

[0068] When the above formula (3) is converted into a formula for deriving Pdiv, the following formula (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 in accordance with 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 in accordance with 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, which are calculated using equation (1) described in the first embodiment. As can be seen from equation (5), a slope that is smaller than that of an operating battery with a low degradation evaluation value is set for an operating battery with a high degradation evaluation value (high health).

[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 and the like may be added to the slope information.

[0074] The power command setting unit 50a calculates an individual power command Pdiv(i) for each operating storage battery using the slope a(i) corresponding to each storage battery and the operating voltage (actually measured voltage) of the DC link 8. For the operating voltage of the DC link 8, for example, information notified from the battery system 1, more specifically, the power conversion device 7′, can be used. Specifically, the power command setting unit 50a acquires the slope a(i) for each storage battery stored in the storage unit 60, and calculates the individual power command Pdiv(i) for 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] After setting 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, charge and discharge control according to the individual power command Pdiv(i) is performed in each operational storage battery.

[0077] For example, an example of the slope and individual power commands when the SOH(2) of storage battery 5b is higher than the SOH(1) of storage battery 5a is shown in comparison in Figure 19. As shown in Figure 19, the individual power commands Pc(2) and Pd(2) of storage battery 5b are larger than those of storage battery 5a, so the charge / discharge current of storage battery 5b is larger than that of storage battery 5a, and the amplitude of the SOC also becomes a larger value than that of storage 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 in accordance with 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 among the storage batteries, as shown in FIG. 20 . FIG. 20 compares the time progression (solid line) of the SOC of a storage battery (e.g., storage battery 5a) with the time progression (dotted line) of a storage battery (e.g., storage battery 5b) with the time progression (dotted line) of the SOC ... Even when power sharing based on the degradation evaluation value is not performed as in the first and second embodiments, variations in the median charging rates between batteries will occur to a certain extent due to individual differences between the batteries, although the degree of variation will vary.

[0080] 20 , when variations in the central SOC values ​​occur among the storage batteries, the upper or lower limit of the charging rate is more likely to reach the allowable upper or lower limit of the battery system 1 than when no variations occur, 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 such variations in the central SOC values ​​among the storage batteries over time. Hereinafter, the same reference numerals will be used to designate components common to the first embodiment, and descriptions thereof will be omitted, and different components will be mainly described.

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

[0082] Fig. 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, an overall average calculation unit 72, and an offset calculation unit 73.

[0083] The individual average calculation unit 71 calculates the individual average charging rate for each storage battery 5, for example, using charging rate data for each storage battery 5 over a predetermined period. For example, battery information (current data, voltage data, temperature data, abnormality detection data, etc.) for each storage battery 5a to 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 over the predetermined period.

[0084] An example of the smoothing process is a moving average. In this embodiment, a 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 identify the maximum charging rate and the minimum charging rate for each storage battery in a predetermined period, and calculate the average value of the identified maximum and minimum charging rates as the individual average charging rate. The present invention is not limited to the above method, and it is also possible to use, as appropriate, a statistical method for calculating an approximate median value of the charging rate in a predetermined period.

[0085] The overall average calculation unit 72 uses the charging rate data for the plurality of storage batteries 5a to 5d over 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 for each storage battery calculated by the individual average calculation unit 71 as the overall average charging rate. For the entire battery system 1, the maximum and minimum charging rates over the predetermined period may be identified, and the average of these values ​​may be calculated as the overall average charging rate. The overall average charging rate may also be calculated by statistically processing the charging rate data for each storage battery over the predetermined period to calculate the median value of the charging rate, and a known technique may be appropriately adopted as the specific method for this.

[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 variation appears in the central value of the charging rate for 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 so as to bring the individual average charging rate of each storage battery 5 closer to the overall average charging rate. For example, considering storage battery 5a, the offset calculation unit 73 calculates the deviation between the individual average charging rate of storage battery 5a and the overall average charging rate, and calculates an individual offset power that reduces the deviation to zero by performing proportional-integral control on this deviation. Similarly, the offset calculation unit 73 calculates individual offset power for each storage battery 5b to 5d. After calculating the individual offset power for each storage battery 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 this individual offset information is updated at predetermined intervals.

[0088] The power command setting unit 50b acquires the individual offset information and the 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 equation (7):

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

[0090] As a result, each operating storage battery is given an individual power command based on the deterioration evaluation value (SOH) and that suppresses SOC variations between storage batteries over time, and charging and discharging control of the power conversion device 7 is performed 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 over 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 operating storage battery using the individual offset power Ps(i) and sharing adjustment rate α(i) for each storage battery.

[0092] In this way, the individual power command for each operating battery is set using the individual offset power Ps, so it is possible to suppress variations in the median SOC value between the batteries over time, as shown in Fig. 23. This makes it possible to lengthen the time until the maximum and minimum charging rates of each operating 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 similarly 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 with 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] 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. Therefore, for example, 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. In this way, when the battery system 1 is connected to the DC link 8, the individual power command Pdiv'(i) may be calculated based on 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 includes a power conversion device 7, a battery monitoring unit (BMU) for monitoring the battery status, and other devices, causing power loss. Because the amount of power loss changes over time, the central value of the charge / discharge range for the entire battery system 1 gradually changes. For example, as shown in FIG. 25 , while charging and discharging are performed around an SOC of 50% in the early stages of operation, charging and discharging may occur around an SOC of 50% or less in the middle to late stages of operation. As such, a decrease in the central value of the charge / discharge range for the entire battery system may make it more likely that the minimum SOC (SOCmin in FIG. 25 ) will reach the lower limit of the allowable value for the storage battery, potentially shortening battery life.

[0097] Therefore, the battery control system 10c according to this embodiment has a function for suppressing such changes 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 will be assigned the same reference numerals and their explanations will be omitted, and the different components will be mainly described.

[0098] Fig. 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. Fig. 27 is a functional configuration diagram showing an example of functions provided in the overall offset power setting unit 80. As shown in Fig. 27, the overall offset power setting unit 80 includes an overall average calculation unit 81 and an offset calculation unit 82.

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

[0100] 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 median value of the charging rate and the median value at the beginning of operation is equal to or greater than a predetermined value for the entire battery system.

[0101] The offset calculation unit 82 calculates the total offset power for bringing the total 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 total average charging rate and the target charging rate, and performs proportional-plus-integral control on this deviation to calculate the total offset power that reduces the deviation to 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 this total offset power Pg is updated at predetermined intervals.

[0102] The system required power correction unit 90 uses the total offset power Pg to correct the system required power received from the grid monitoring system 6. For example, the system required power correction unit 90 reads out the total offset power Pg stored in the storage unit 60 and adds the total offset power Pg to the system required power Pall to calculate the corrected system required power Pall' (=Pall+Pg). 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 the individual power command Pdiv'(i) of 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 control of the power conversion device 7 is performed 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 includes an overall average calculation unit 81 that calculates an overall average charging rate, which is the average charging rate of the battery system 1, using charging rate data of the battery system 1 over a predetermined period, and an offset calculation unit 82 that calculates an overall offset power to bring the overall average charging rate closer to a predetermined reference charging rate. The power command setting unit 50c then sets individual power commands for each operating storage battery using the sharing adjustment rate α(i) and the corrected system required power Pall′.

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

[0108] [Modification 4-1] In the present embodiment, the overall offset power is calculated using the overall average charging rate of the battery system 1, but this is not limited to this. Fig. 28 shows a functional configuration diagram of an overall offset power setting unit 80a according to a modification. As shown in Fig. 28, the overall 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 of the maximum charging rates of the storage batteries 5a to 5d may be used as the upper limit representative charging rate, and the average of the minimum charging rates of the storage batteries 5a to 5d may be used as the lower limit representative charging rate. 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 an overall offset power to bring 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] The overall offset power setting unit 80a according to the modification 4-1 can control the operational fluctuation range of the charging rate of the entire battery system to be approximately the center between the allowable upper limit and the allowable lower limit, thereby preventing the center of the operational fluctuation range of the charging rate of the entire battery system from gradually shifting, thereby extending 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 then performs power control based on the total offset power.

[0112] The battery control system 10c according to the fourth embodiment and modification 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 that corrects the individual power command of each operational storage battery using an individual offset, it is possible to suppress deviation over time of the central value of the SOC of the entire battery system and to suppress deviation of the central value of the SOC between the storage batteries that make up the battery system 1.

[0113] Although the present disclosure has been described above using 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 forms incorporating such modifications or improvements are also included in the technical scope of the present disclosure. The above embodiments may be combined as appropriate. The processing flow described in the above embodiments is also an example, and unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged without departing from the gist 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 are no particular limitations on the location of the storage unit 60. For example, the storage unit 60 may be accessible by the battery control systems 10, 10a, 10b, and 10c, and may be configured to enable reading and writing of data from and 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 preset 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 that 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 power required from a higher-level system such as a grid power. In this case, the operational storage batteries are assigned power based on their degradation evaluation values. This makes it possible to suppress variations in the degradation evaluation values ​​between the storage batteries and extend the life of the entire battery system.

[0118] In the battery control system (10) according to the second aspect of the present disclosure, in the first aspect, the degradation state evaluation unit (20) controls the storage battery to be evaluated so that the charge state of the storage battery to be evaluated approaches the charge state of the operational storage battery after charge / discharge control based on the charge / discharge pattern is completed, and includes a restoration control unit (23) that restores 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 degradation state is completed. Examples of parameters indicating the state of charge include a charging rate and a parameter related to a cell voltage.

[0120] In the battery control system (10) according to the 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 the deterioration evaluation value of each of the storage batteries constituting 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 is in any of the first to third aspects, and 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 of the storage batteries using charging rate data for each of the storage batteries over 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, for each of the storage batteries, an individual offset power for bringing the individual average charging rate closer to the overall average charging rate, and the power command setting unit (50) sets an individual power command for each of the operational storage batteries that are the storage batteries other than those being evaluated, using the individual offset power for each of the storage batteries and the sharing adjustment rate.

[0123] According to the above aspect, it is possible to bring the average state of charge of each storage battery closer to the overall average state of charge. This makes it possible to suppress variations in the median SOC value among the storage batteries over time. As a result, it is possible to lengthen the time until the maximum and minimum state of charge 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, includes an overall offset power setting unit (80) that calculates an overall offset power for correcting 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) over a predetermined period, 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.

[0125] According to the above aspect, an overall average charging rate, which is the average charging rate of the battery system over 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 changes in the median charging rate of the entire battery system over time. As a result, it is possible to lengthen the time it takes for the maximum and minimum charging rates of the storage batteries to reach their allowable upper and lower limits, and further extend the life of the entire battery system.

[0126] A battery control system (10) according to a sixth aspect of the present disclosure, in any of the first to fourth aspects, 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 overall offset power to bring the difference between the upper limit representative charging rate and the allowable upper limit value of the charging rate and the difference between the lower limit representative charging rate and the allowable lower limit value of the charging rate closer to zero.

[0127] According to the above aspect, an upper representative charging rate, which is a representative value of the upper limit of the charging rate in the battery system, and a lower representative charging rate, which is a representative value of the lower limit of the charging rate in the battery system, are determined. Then, 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. The calculated overall offset power is then used to correct the system required 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 changes in the central value of the charging rate of the entire battery system over time. As a result, it is possible to extend the time it takes for the maximum and minimum charging rates of the storage batteries to reach the allowable upper and lower limits, and further extend the life of the entire battery system. By using the maximum and minimum charging rates, for example, even when the charging and discharging of some storage batteries is controlled near the allowable upper and lower limits, it is possible to evenly distribute the charging and discharging range of the entire battery system between the allowable upper and lower limits.

[0128] An electricity supply and demand system (100, 100a) according to a seventh aspect of the present disclosure includes a battery system (1, 1a) having a plurality of storage batteries and a battery control system (10, 10a, 10b, 10c) described in 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 having a plurality of storage batteries, and is executed by a computer to perform a degradation state evaluation process of 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 batteries to be evaluated using voltage values ​​or current values ​​when charging and discharging of the storage batteries to be evaluated according to a predetermined charge and discharge pattern; a data management process of associating identification information of the storage batteries with the degradation evaluation values ​​and storing them in a memory unit; a sharing adjustment rate setting process of setting a sharing adjustment rate using the degradation evaluation values ​​of the plurality of storage batteries; and a power command setting process of using 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.

[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.

[0131] DESCRIPTION OF SYMBOLS 1, 1a: Battery system 2: Power system 3: Substation 4: AC link 5 (5a to 5d): Storage battery 6: System monitoring system 7 (7a to 7d): Power conversion device 7' (7a' to 7d'): Power conversion device 8: DC link 9: AC / DC converter 10, 10a, 10b, 10c: Battery control system 11: CPU 12: Main memory device 13: Secondary memory device 14: Communication interface 15: Input device 16: Display 20: Degradation state evaluation unit 21: Selection unit 22: Measurement execution unit 23: Recovery control unit 24: Evaluation value calculation unit 30: Data management unit 40, 40a: Sharing adjustment rate setting unit 50, 50a, 50b, 50c: Power command setting unit 60: Storage unit 70: Individual offset power setting unit 71: Individual average calculation unit 72: Overall average calculation unit 73: Offset calculation unit 80, 80a: Overall offset power setting unit 81: Overall average calculation unit 82: Offset calculation unit 83: Representative charging rate determination unit 84: Offset calculation unit 90: System required power correction unit 100, 100a: Power supply and demand system

Claims

1. A battery control system applicable to a battery system having a plurality of storage batteries, comprising: a degradation state evaluation unit 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 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.

2. 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 / discharge control based on the charge / discharge pattern is completed, and restores 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. A battery control system as described in 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 that brings the deterioration evaluation value of each of the storage batteries closer to the target deterioration evaluation value.

4. A battery control system as described in claim 1, comprising an individual offset power setting unit that calculates an individual offset power for correcting the individual power command, the individual offset power setting unit comprising: 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 in a specified period; an overall average calculation unit that calculates an overall average charging rate that serves as a reference for the entire battery system; and 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, and the power command setting unit sets individual power commands for each operational storage battery that is a storage battery other than the storage battery to be evaluated, using the individual offset power for each of the storage batteries and the sharing adjustment rate.

5. A battery control system as described in claim 1, comprising: an overall offset power setting unit that calculates an overall offset power for correcting system required power; and a system required power correction unit that corrects the system required power of the battery system using the overall offset power, wherein the overall offset power setting unit comprises: 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 over a predetermined period; and an offset calculation unit that calculates an overall offset power to bring the overall average charging rate closer to a predetermined reference charging rate.

6. A battery control system as described in claim 1, comprising: an overall offset power setting unit that calculates an overall offset power for correcting system required power; and a system required power correction unit that corrects the system required power of the battery system using the overall offset power, wherein the overall offset power setting unit comprises: 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 for a predetermined period; and an offset calculation unit that calculates an overall offset power to bring a difference between the 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.

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

8. A battery control method applied to a battery system having a plurality of storage batteries, the battery control method being executed by a computer to perform the following steps: a degradation state evaluation step of 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 preset charge and discharge pattern; a data management step of associating identification information of the storage battery with the degradation evaluation value and storing them in a memory unit; a sharing adjustment rate setting step of setting a sharing adjustment rate using the degradation evaluation values ​​of the plurality of storage batteries; and a power command setting step of using 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.

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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