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

Abstract

The purpose of the present invention is to extend the life of the overall battery system. This battery control system is provided with: a low-capacity battery setting unit (23) for setting a low-capacity battery for reducing the frequency of use on the basis of a deterioration evaluation value relating to the full charge capacity of each storage battery when a battery system is started; an initial power command setting unit (24) for setting an individual power command for the storage battery so as to reduce the frequency of use of the low-capacity battery compared to an operation battery which is a storage battery other than the low-capacity battery; and a setting release unit (25) for acquiring the deterioration evaluation value of each storage battery after the low-capacity battery is set, and cancelling the setting of the low-capacity battery when the acquired deterioration evaluation value of each storage battery satisfies a predetermined cancellation condition.

Description

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

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

[0002] In order to grasp the state of a storage battery, there are known techniques for measuring the SOC (State of Charge, charging rate) and the SOH (State of Health). For example, Patent Document 1 discloses a battery state of charge calculation method that obtains a linear approximation of the current-voltage characteristics of a battery from the battery current and battery voltage, and estimates the state of charge and / or the state of deterioration of the battery using the slope and intercept of the equation.

[0003] Japanese Patent Application Laid-Open No. 2005-345135

[0004] However, although the invention of Patent Document 1 estimates battery characteristics (battery performance level, SOH) and determines the life of the battery (storage battery), it does not consider the operation of a battery system when there is variation in the battery characteristics of multiple batteries. When there is variation in the battery characteristics of multiple batteries included in a battery system, it is difficult to extend the life of the entire battery system.

[0005] The present disclosure has been made in consideration of these circumstances, and aims to provide a battery control system, a power supply and demand system, a battery control method, and a battery control program that can extend the life of the entire battery system.

[0006] 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 comprising: a low-capacity battery setting unit that sets a low-capacity battery to be used less frequently based on a deterioration evaluation value related to the full charge capacity of each of the storage batteries when the battery system is started; an initial power command setting unit that sets individual power commands for the storage batteries so as to reduce the frequency of use of the low-capacity battery compared to operational batteries that are storage batteries other than the low-capacity battery; and a setting cancellation unit that acquires a deterioration evaluation value for each of the storage batteries after the low-capacity battery has been set, and cancels the setting of the low-capacity battery when the acquired deterioration evaluation value for each of the storage batteries satisfies a predetermined cancellation condition.

[0007] 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.

[0008] One aspect of the present disclosure is 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 when the battery system is started: setting a low-capacity battery to reduce the frequency of use based on a deterioration evaluation value related to the full charge capacity of each of the storage batteries; setting individual power commands for the storage batteries so as to reduce the frequency of use of the low-capacity battery compared to operational batteries that are storage batteries other than the low-capacity battery; and acquiring a deterioration evaluation value for each of the storage batteries after the low-capacity battery has been set, and canceling the setting of the low-capacity battery when the acquired deterioration evaluation value for each of the storage batteries satisfies a predetermined cancellation condition.

[0009] One aspect of the present disclosure is a program for causing a computer to function as the battery control system.

[0010] The life of the entire battery system can be extended.

[0011] 7 is a diagram illustrating a schematic configuration of an electric power supply and demand system according to a first embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example of a hardware configuration of a battery control system according to a first embodiment of the present disclosure. FIG. 9 is a functional configuration diagram illustrating an example of functions possessed by the battery control system according to the first embodiment of the present disclosure. FIG. 10 is a functional configuration diagram illustrating an example of functions possessed by an initial operation control unit according to the first embodiment of the present disclosure. FIG. 11 is a diagram illustrating a comparison of an example of transitions between the full charge capacity of a low-capacity battery and a representative value of the full charge capacity of an operational battery when the initial operation control according to the first embodiment of the present disclosure is performed. FIG. 12 is a functional configuration diagram illustrating an example of functions possessed by a mid-term operation control unit according to the first embodiment of the present disclosure. FIG. 13 is a diagram illustrating an example of a sharing adjustment rate for a storage battery. As shown in FIG. 7, an example of individual power commands when 0.8 and 1.2 are set as the sharing adjustment rate is shown for comparison. As shown in FIG. 7, an example of charge and discharge currents when 0.8 and 1.2 are set as the sharing adjustment rate is shown for comparison. As shown in FIG. 7, an example of SOCs when 0.8 and 1.2 are set as the sharing adjustment rate is shown for comparison. FIG. 14 is a functional configuration diagram illustrating an example of functions possessed by a later operation control unit according to the first embodiment of the present disclosure. 1 is a diagram for explaining that variations occur in the central value of the charging rate among storage batteries over time. FIG. 1 is a flowchart showing an example of the procedure of an initial operation control method executed by the battery control system according to the first embodiment of the present disclosure. FIG. 2 is a flowchart showing an example of the procedure of a mid-term operation control method executed by the battery control system according to the first embodiment of the present disclosure. FIG. 3 is a flowchart showing an example of the procedure of a late operation control method executed by the battery control system according to the first embodiment of the present disclosure. FIG. 4 is a diagram for explaining the effect of the late operation control unit according to the first embodiment of the present disclosure. FIG. 5 is a diagram for explaining that the center of the SOC of the entire battery system tends to shift over time. A functional configuration diagram showing an example of functions provided in the late operation control unit according to the second embodiment of the present disclosure. A functional configuration diagram showing modified examples of functions provided in the late operation control unit according to the second embodiment of the present disclosure. A diagram showing a schematic configuration of a power supply and demand system according to a third embodiment of the present disclosure. A functional configuration diagram showing an example of functions provided in the mid-term operation control unit of the battery control system according to the third embodiment of the present disclosure.10 is a diagram showing a relationship between an individual power command and a bus voltage of a DC link according to a third embodiment of the present disclosure. FIG. 11 is a diagram showing an example of a relationship between the slope of storage batteries with different SOH and individual power commands. FIG. 12 is a functional configuration diagram showing an example of a function provided in a post-operation control unit of a battery control system according to a third embodiment of the present disclosure. FIG. 13 is a diagram for explaining individual offset power when a battery system is connected to a DC link.

[0012] [First embodiment] Hereinafter, a power supply and demand system, a battery control system, a battery control method, and a battery control 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 a first 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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, etc. The battery control system 10 may also include an input device 15 that accepts input from a user, a display 16, etc.

[0018] 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).

[0019] FIG. 3 is a functional configuration diagram showing an example of functions possessed by the battery control system 10 according to this embodiment. The battery control system 10 charges and discharges the battery system 1 by employing different control methods depending on the operation phase (e.g., early, middle, or late) of the battery system. Specifically, as illustrated in FIG. 3 , the battery control system 10 includes an early operation control unit 20, a mid-operation control unit 30, a late operation control unit 40, and a control switching unit 50. The early operation control unit 20 performs early operation control in the early operation of the battery system 1. The mid-operation control unit 30 performs mid-operation control in the mid-operation of the battery system 1. The late operation control unit 40 performs late operation control in the late operation of the battery system 1. Details of the early operation control unit 20, the mid-operation control unit 30, and the late operation control unit 40 will be described later. The control switching unit 50 has switching conditions (cancellation conditions) for switching from early operation control to mid-operation control, and switching conditions (late operation conditions) for switching from mid-operation control to late operation control, and switches control when these switching conditions are met.

[0020] 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.

[0021] [Initial Operation Control Unit 20] FIG. 4 is a functional configuration diagram illustrating an example of functions included in the initial operation control unit 20 according to this embodiment. As shown in FIG. 4, the initial operation control unit 20 includes, for example, a degradation state evaluation unit 21, a storage unit 22, a low-capacity battery setting unit 23, an initial power command setting unit 24, and a setting cancellation unit 25. The degradation state evaluation unit 21 acquires a degradation evaluation value related to the full charge capacity of each of the storage batteries 5a to 5d. For example, the degradation state evaluation unit 21 performs a degradation state evaluation to acquire a degradation evaluation value when a preset start condition is satisfied. Examples of the start condition include the initial start of the battery system 1, when a predetermined period has elapsed 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 a 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.

[0022] An example of a degradation evaluation value is the SOH. The SOH is the ratio of the most recent (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 most recent (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 degradation state evaluation unit 21 calculates the most recent full charge capacity (Ah) by, for example, integrating the current value when the storage battery 5 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. In the process of calculating the most recent full charge capacity, correction may be made based on differences in test conditions (rate, temperature, etc.). The degradation state evaluation unit 21 calculates degradation evaluation values ​​(e.g., SOH) for all storage batteries 5a to 5d using the acquired most recent full charge capacities (Ah), and then stores battery evaluation information in the memory unit 22, which associates the identification information of each storage battery 5 with the degradation evaluation value. The battery evaluation information may include time information and battery information of each of the storage batteries 5a to 5d acquired from the battery system 1. The degradation evaluation value is not limited to the SOH, and may be any evaluation value related to the full charge capacity of each of the storage batteries 5a to 5d. For example, a known evaluation value for evaluating the degradation state of the storage batteries may be used, and as an example, the full charge capacity (Ah) of each storage battery 5 may be used.

[0023] At the start of the battery system 1, the low-capacity battery setting unit 23 sets a low-capacity battery to be used less frequently based on the degradation evaluation value (e.g., SOH) of each of the storage batteries 5 a to 5 d acquired by the degradation state evaluation unit 21. For example, at the start of the battery system 1, the low-capacity battery setting unit 23 acquires the degradation evaluation value of each of the storage batteries 5 a to 5 d from the storage unit 22, identifies the maximum and minimum values ​​from the acquired degradation evaluation values, and calculates the difference between these values. If the difference is greater than a preset threshold, the low-capacity battery setting unit 23 sets the storage battery 5 with the minimum degradation evaluation value as a low-capacity battery. The number of storage batteries set as low-capacity batteries is not limited. For example, if the battery system 1 has a surplus battery capacity, multiple storage batteries may be set as low-capacity batteries.

[0024] The initial power command setting unit 24 sets an individual power command for each storage battery 5 based on, for example, a control algorithm at the start of operation. Specifically, the initial power command setting unit 24 sets the individual power command for each storage battery 5 so as to reduce the frequency of use of the low-capacity battery compared to the operational batteries other than the low-capacity battery. For example, the initial power command setting unit 24 stops operation of the low-capacity battery (e.g., storage battery 5a) by setting the individual power command to zero, and sets the individual power commands for each storage battery 5 by equally distributing the system required power Pall obtained from the grid monitoring system 6 for the operational batteries other than the low-capacity battery (e.g., storage batteries 5b to 5d). The method of setting individual power commands for the low-capacity batteries and operational batteries is not limited to the above.

[0025] That is, since the low-capacity batteries only need to be used less frequently than the operational batteries, the system required power Pall may be allocated equally to the low-capacity batteries at a predetermined frequency (e.g., 20% of the operational battery usage rate of 100%), similar to the operational batteries. The allocation rate of the system required power to the low-capacity batteries may also be set lower than that of the operational batteries. For the operational batteries, the system required power Pall may be allocated to each operational battery at an allocation rate according to the full charge capacity, for example. If the battery capacity of the battery system 1 is insufficient to meet the power required from the power grid, it is difficult to reduce the usage frequency of the low-capacity batteries. In this case, it is necessary to set an individual power command for the low-capacity batteries that is the same as for the other operational batteries. In this way, an appropriate individual power command may be set for the low-capacity batteries based on the relationship between the system required power from the power grid and the battery capacity of the battery system 1.

[0026] When the initial power command setting unit 24 sets the individual power command for each storage battery 5, it transmits the individual power command to the power conversion device 7 corresponding to each storage battery 5. As a result, charge and discharge control according to the individual power command is performed in each storage battery.

[0027] In this way, by reducing the frequency of use of the low-capacity battery (e.g., storage battery 5a) compared to the operational batteries (e.g., storage batteries 5b to 5d), it is possible to gradually bring the full charge capacity of the operational battery, which showed a high full charge capacity at the beginning of operation, closer to the full charge capacity of the low-capacity battery, as illustrated in Figure 5, for example.

[0028] The setting cancellation unit 25 acquires the deterioration evaluation values ​​of each of the storage batteries 5a to 5d after the storage batteries 5a to 5d have been set as a low-capacity battery (e.g., the storage battery 5a). For example, the setting cancellation unit 25 acquires the deterioration evaluation values ​​of each of the storage batteries 5a to 5d stored in the memory unit 22 each time the deterioration evaluation values ​​are updated. Then, the setting cancellation unit 25 cancels the setting of the low-capacity battery (e.g., the storage battery 5a) when the acquired deterioration evaluation values ​​of each of the storage batteries 5a to 5d satisfy a predetermined cancellation condition.

[0029] Examples of the release conditions include (i) when the differences between the degradation evaluation values ​​of each operating battery (e.g., storage batteries 5b to 5d) and the degradation evaluation value of the low-capacity battery are all equal to or less than the release threshold, (ii) when the difference between a representative value (e.g., minimum value, maximum value, average value, average value - N times standard deviation, etc.) of the degradation evaluation values ​​of each operating battery and the degradation evaluation value of the low-capacity battery is equal to or less than the release threshold, etc. When the setting release unit 25 releases the low-capacity battery setting in this manner, the control switching unit 50 (see FIG. 3) switches to control by the mid-term operation control unit 30.

[0030] [Medium-term operation control unit 30] Fig. 6 is a functional configuration diagram showing an example of functions included in the medium-term operation control unit 30 according to this embodiment. As shown in Fig. 6, the medium-term operation control unit 30 includes, for example, a degradation state assessment unit 31, a storage unit 32, a sharing adjustment rate setting unit 33, and a medium-term power command setting unit 34.

[0031] The degradation state evaluation unit 31 has the same functions as the degradation state evaluation unit 21 included in the initial operation control unit 20, and acquires a degradation evaluation value for each of the storage batteries 5a to 5d. For example, the degradation state evaluation unit 31 performs a degradation state evaluation to acquire a degradation evaluation value when a preset start condition is satisfied. Examples of the start condition include when a predetermined period has elapsed since the previous degradation state evaluation, when the cumulative operating time since the previous degradation state evaluation reaches a predetermined time, or when a command to start a degradation state evaluation is input by a 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. The degradation evaluation value has been described above, and therefore a detailed description thereof will be omitted here.

[0032] The sharing adjustment rate setting unit 33 sets a sharing adjustment rate for each of the storage batteries 5a to 5d based on the deterioration evaluation value (e.g., SOH) of each of the storage batteries 5a to 5d stored in the memory unit 32. For example, the sharing adjustment rate setting unit 33 calculates a target deterioration evaluation value using the deterioration evaluation values ​​(e.g., SOH) of the storage batteries 5a to 5d that constitute the battery system 1, and sets a sharing adjustment rate for each storage battery 5 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.

[0033] 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.

[0034] For example, the sharing adjustment rate setting unit 33 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).

[0035] Sharing adjustment rate α(i) = {1+K(ΔSOH(i) / SOHave)} (1)

[0036] 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.

[0037] Sharing adjustment rate α(1) = {1+K(ΔSOH(1) / SOHave)}

[0038] In the above formula (1), K is an adjustment gain, and the larger this adjustment gain K is, the shorter the time it takes for the variation in the degradation evaluation value to fall within a predetermined range. The adjustment gain K is a value equal to or greater than zero, and its upper limit is set within a range in which the sum of the individual power commands assigned to the operating batteries does not exceed the system required power. In the middle stage of operation, the adjustment gain K is set to a value equal to or greater than 1, specifically, a value greater than 1.

[0039] For example, when the battery evaluation information stored in the memory unit 32 is updated, the sharing adjustment rate setting unit 33 calculates the sharing adjustment rate α(i) using the latest deterioration evaluation value and updates each sharing adjustment rate α(i) in the memory unit 32.

[0040] After calculating the sharing adjustment rate α(i) for each of the storage batteries 5a to 5d, the sharing adjustment rate setting unit 33 stores sharing adjustment rate information that associates the identification information of each storage battery with the sharing adjustment rate α(i) in the storage unit 32. The sharing adjustment rate information may also include time information and the like.

[0041] The medium-term power command setting unit 34 calculates an individual power command Pdiv(i) for each operating battery, for example, using the sharing adjustment rate α(i) corresponding to each of the storage batteries 5a to 5d and the system required power Pall obtained from the grid monitoring system 6. Here, the operating battery is an operable storage battery, in other words, a storage battery (for example, the storage batteries 5a to 5d) that can be controlled to charge and discharge in response to the system required power Pall.

[0042] The medium-term power command setting unit 34 acquires the sharing adjustment rate α(i) of each operating battery stored in the memory unit 32, and calculates the individual power command Pdiv(i) of each operating battery by using the acquired sharing adjustment rate α(i) and the system required power Pall in the following equation (2).

[0043] Pdiv(i)=Pall×(1 / N)×α(i) (2)

[0044] In the above formula (2), N represents the number of operating batteries. As can be seen from formula (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 assigning an individual power command Pdiv(i) to each operating battery, the medium-term power command setting unit 34 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 for each operating battery.

[0045] 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. 7, examples of the individual power commands, charge / discharge currents, and SOCs are shown in FIGS. 8 to 10, respectively. In FIGS. 8 to 10, the solid lines represent battery 5a and the dashed lines represent battery 5b. As shown in FIGS. 8 to 10, 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.

[0046] Then, when the state of the storage battery 5 satisfies a later-stage operation condition as a result of the mid-stage operation control unit 30 repeatedly controlling the storage battery 5 based on the sharing adjustment rate α corresponding to the degradation evaluation value, the control switching unit 50 (see FIG. 3 ) switches to control by the later-stage operation control unit 40. Examples of the later-stage operation condition include (i) when a parameter indicating the battery state of the operating storage battery (e.g., voltage, SOC, temperature, etc.) becomes equal to or less than a later-stage determination reference value set based on an operational allowable lower limit, (ii) when a representative value of the SOH of the storage battery of the battery system 1 (e.g., average, minimum, or maximum value) becomes equal to or less than a later-stage threshold, or (iii) when the cumulative operating time of the battery system 1 exceeds a predetermined time.

[0047] [Late-stage operation control unit 40] Figure 11 is a functional configuration diagram showing an example of functions included in the late-stage operation control unit 40 according to this embodiment. As shown in Figure 11, the late-stage operation control unit 40 includes, for example, a degradation state assessment unit 41, a storage unit 42, a sharing adjustment rate setting unit 43, an individual offset power setting unit 44, and a late-stage power command setting unit 45. The degradation state assessment unit 41 and the sharing adjustment rate setting unit 43 have the same functions as the degradation state assessment unit 31 and the sharing adjustment rate setting unit 33 included in the mid-stage operation control unit 30, and therefore detailed description thereof will be omitted here, and the following description will mainly focus on the storage unit 42, the individual offset power setting unit 44, and the late-stage power command setting unit 45.

[0048] For example, when the above-described mid-term operation control unit 30 performs control to change the power sharing in accordance with the degradation evaluation value of the storage batteries 5, there is a risk that the median value of the state of charge (SOC) among the storage batteries will vary over time, as shown in Fig. 12. Fig. 12 is a diagram comparing the time progression (solid line) of the SOC of a storage battery (e.g., storage battery 5a) having a relatively small sharing adjustment rate, in other words, a relatively low degradation evaluation value (e.g., SOH), with the time progression (dotted line) of a storage battery (e.g., storage battery 5b) having a relatively large sharing adjustment rate, in other words, a relatively high degradation evaluation value (e.g., SOH).

[0049] For example, the discharge current tends to be large and the charge current tends to be small for storage battery 5b (e.g., a storage battery with a sharing adjustment rate of 1 or more), and the discharge current tends to be small and the charge current tends to be large for storage battery 5a (e.g., a storage battery with a sharing adjustment rate of less than 1). Even when power sharing based on a degradation evaluation value (e.g., SOH) is not performed as in the mid-term operation control unit 30, the degree of variation in the median charge rate among storage batteries will vary to a certain extent due to individual differences between storage batteries.

[0050] 12 , 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 post-operation control unit 40 includes an individual offset power setting unit 44 as a function for reducing such variations in the central SOC values ​​among the storage batteries over time.

[0051] The individual offset power setting unit 44 includes an individual average calculation unit 61, an overall average calculation unit 62, and an offset calculation unit 63. The individual average calculation unit 61 calculates an 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, anomaly detection data, etc.) for each storage battery 5a to 5d is repeatedly transmitted from the battery system 1 to the post-operation control unit 40 at predetermined time intervals. The individual average calculation unit 61 calculates the individual average charging rate by performing a smoothing process on the charging rate data (SOC data) for each storage battery over a predetermined period. An example of the smoothing process is a moving average.

[0052] For example, the individual average calculation unit 61 performs a smoothing process such as a moving average, and further calculates the average value of the smoothing process to calculate the individual average charging rate for each storage battery 5. 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 61 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 charging rate and minimum charging rate 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.

[0053] The overall average calculation unit 62 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 62 may calculate the average value of the individual average charging rates for each storage battery calculated by the individual average calculation unit 61 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.

[0054] 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.

[0055] The offset calculation unit 63 calculates, for each storage battery 5, an individual offset power for bringing 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 63 calculates the deviation between the individual average charging rate of storage battery 5a and the overall average charging rate, and performs proportional-plus-integral control on this deviation to calculate an individual offset power that reduces the deviation to zero. Similarly, the offset calculation unit 63 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 63 stores individual offset information in the storage unit 42, which associates the identification information of each storage battery with the individual offset power. As a result, the individual offset information is stored in the storage unit 42, and this individual offset information is updated at predetermined intervals.

[0056] The later-stage power command setting unit 45 acquires the individual offset power Ps(i) and the sharing adjustment rate α(i) stored in the storage unit 42, and sets the individual power command Pdiv'(i) for the operating 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 (3):

[0057] Pdiv'(i)={Pall×(1 / N)×α(i)}+Ps(i) (3) Here, α(i)={1+K(ΔSOH(i) / SOHave)}

[0058] Here, in the later stage of operation, it is preferable to set the adjustment gain K to approximately 1. For example, when the adjustment gain K=1, the sharing adjustment rate α(i) of each of the storage batteries 5a to 5d is given by the following equation (1.1) from the above-mentioned equation (1).

[0059] Sharing adjustment rate α(i) = {1+(ΔSOH(i) / SOHave)} (1.1)

[0060] For example, if SOHave=50% and SOH(1)=50% for i=1, then ΔSOH(1)=0%, and the sharing adjustment rate α(1) is as follows:

[0061] Sharing adjustment rate α(1)={1+(ΔSOH(1) / SOHave)}=1

[0062] If SOHave = 50% and SOH(2) of i = 2 = 100% (twice the SOH of the battery i = 1), then ΔSOH(2) = 50%, and the sharing adjustment rate α(2) is as follows.

[0063] Sharing adjustment rate α(2)={1+(ΔSOH(2) / SOHave)}=2

[0064] In other words, for a battery with twice the SOH, the sharing adjustment rate is also doubled, and twice the charging and discharging is performed. This type of control makes it possible to operate each battery so that its SOC behavior is approximately the same.

[0065] If the adjustment gain K is set to zero in the later stage of operation, the sharing adjustment rate of each of the storage batteries 5a to 5d will all be 1, and in this case, there will be no increase or decrease in the power sharing according to the SOH(i). That is, the system required power will be allocated equally to each storage battery, and an individual power command Pdiv'(i) will be given in which the individual offset power Ps(i) has been added to that allocation. If the adjustment gain K is set to zero in the later stage of operation, there will be no need to calculate the sharing adjustment rate, and therefore the sharing adjustment rate setting unit 43 may be omitted.

[0066] After setting the individual power command Pdiv'(i) for each operating battery, the later-stage power command setting unit 45 transmits the individual power command Pdiv'(i) to the power conversion device 7 corresponding to each operating battery. As a result, charge / discharge control according to the individual power command Pdiv'(i) is performed in each operating battery.

[0067] Next, the operation of the battery control system 10 according to this embodiment will be described. First, the initial operation control according to this embodiment will be described with reference to FIG. 13. FIG. 13 is a flowchart showing an example of the processing procedure for the initial operation control according to this embodiment. In the following description, a case where SOH is used as the degradation evaluation value will be described as an example.

[0068] First, during initial operation of the battery system 1, the battery control system 10 acquires the full charge capacity (Ah) of each storage battery 5a-5d constituting the battery system 1 and calculates the SOH using the acquired full charge capacity (SA1). Next, the battery control system 10 calculates the difference between the maximum and minimum SOH values ​​(SA2) and determines whether the difference is greater than a set threshold (SA3). If the difference is equal to or less than the set threshold (SA3: NO), the system switches to mid-term operation control (SA9) and ends this process.

[0069] On the other hand, if the difference is greater than the set threshold in step SA3 (SA3: YES), the storage battery 5 with the smallest SOH value is designated as a low-capacity battery (SA4). Next, charge / discharge control of the storage batteries 5 is performed based on the control algorithm used at the start of operation (SA5). For example, the individual power command for the low-capacity battery is set to zero to stop operation, and the system required power Pall is evenly distributed to the operating batteries other than the low-capacity battery to set the individual power command for each storage battery. The set individual power command is then provided to each power conversion device 7 of the battery system 1, thereby performing charge / discharge control of the storage batteries 5 based on the individual power command.

[0070] Next, it is determined whether the SOH in the storage unit 22 (see FIG. 4) has been updated (SA6). If it has not been updated (SA6: NO), the process returns to step SA5, where charge / discharge control of the storage battery 5 is performed based on the control algorithm for the initial operation. On the other hand, if it has been updated (SA6: YES), it is determined whether the cancellation condition is met (SA7). As a result, if the cancellation condition is not met (SA7: NO), the process returns to step SA5, and the above-described process is repeated. On the other hand, if the cancellation condition is met (SA7: YES), the low-capacity battery setting is canceled (SA8), and the process is switched to mid-operation control (SA9), and this process ends.

[0071] Next, the mid-term operation control according to this embodiment will be described with reference to FIG. 14 . FIG. 14 is a flowchart illustrating an example of the processing procedure for the mid-term operation control according to this embodiment. First, the sharing adjustment rate is calculated based on the latest SOH of each storage battery and stored in the memory unit 32 (see FIG. 6 ) (SB1). Next, charge / discharge control of the storage battery 5 is performed based on the mid-term operation control algorithm (SB2). Specifically, the sharing adjustment rate α(i) of each storage battery 5 a-5 d is acquired from the memory unit 32, and individual power commands are set for each operating battery using the acquired sharing adjustment rate α(i), and each individual power command is sent to each operating battery. This allows charge / discharge control that reflects the deterioration evaluation value (e.g., SOH(i)) of each operating battery. Next, it is determined whether the SOH stored in the memory unit 32 has been updated (SB3). If the SOH has not been updated (SB3: NO), the process returns to step SB2, and charge / discharge control of the storage battery 5 is performed based on the mid-term operation control algorithm. On the other hand, if the SOH has been updated (SB3: YES), it is determined whether the degradation state of the storage battery 5 satisfies the later-stage operation condition (SB4). Specifically, it is determined whether the representative value of the SOH of the storage battery 5 is equal to or less than the later-stage threshold. As a result, if the later-stage operation condition is not satisfied (SB4: NO), the process returns to step SB1, the sharing adjustment rate is calculated using the latest SOH, the sharing adjustment rate is stored in the memory unit 32, and subsequent processing is performed. On the other hand, if the later-stage operation condition is satisfied in step SB4 (SB4: YES), the process switches to later-stage operation control (SB5), and this process ends.

[0072] Next, the post-operation control according to this embodiment will be described with reference to FIG. 15 . FIG. 15 is a flowchart showing an example of the processing procedure for the post-operation control according to this embodiment. First, an individual offset power is calculated based on battery information acquired from each battery system 1 and stored in a memory unit (SC1). Next, charge / discharge control of the storage batteries 5 is performed based on a control algorithm for the post-operation period (SC2). Specifically, the sharing adjustment rate α(i) and individual offset power Ps(i) of each storage battery 5a to 5d are acquired from the memory unit 42 (see FIG. 11 ). An individual power command is set for each operating battery using the sharing adjustment rate α(i) and individual offset power Ps(i), and each individual power command is transmitted to each operating battery.

[0073] Next, it is determined whether the SOH stored in the storage unit 42 has been updated (SC3). As a result, if the SOH has been updated (SA3: YES), the sharing adjustment rate is calculated using the new SOH and stored in the storage unit 42 (SC4), and the process proceeds to step SC5.

[0074] On the other hand, if the SOH has not been updated (SC3: NO), it is determined whether the update condition for the individual offset power is met (SC5). As a result, if the update condition is met (SC5: YES), for example, if a predetermined period has elapsed since the previous calculation of the individual offset power, the process returns to step SC1 and performs subsequent processing. On the other hand, if the update condition is not met in step SC5 (SC5: NO), it is determined whether the battery system 1 has met the operation stop condition (SC6). Specifically, it is determined whether the upper limit of the charge rate of each storage battery 5a-5d has reached an allowable upper limit, or whether the lower limit of the charge rate of each storage battery 5a-5d has reached an allowable lower limit. As a result, if the operation stop condition is not met (SC6: NO), the process returns to step SC2 and performs charge / discharge control of the storage battery 5 based on the control algorithm for the later stage of operation. On the other hand, if the battery system 1 meets the operation stop condition (SC6: YES), it is determined that the battery system 1 has reached the end of its life, a notification of operation stop is issued (SC7), and the process ends.

[0075] As described above, the battery control system 10 according to this embodiment includes an initial operation control unit 20 that performs initial operation control during the initial operation period, including the start-up of the battery system 1. Specifically, the initial operation control unit 20 includes a low-capacity battery setting unit 23 that sets a low-capacity battery to be used less frequently based on a degradation evaluation value (e.g., full charge capacity) related to the full charge capacity of each of the storage batteries 5 a to 5 d, an initial power command setting unit 24 that sets individual power commands for the storage batteries 5 so as to reduce the frequency of use of the low-capacity batteries compared to the operating batteries, which are storage batteries other than the low-capacity batteries, and a setting cancellation unit 25 that acquires a degradation evaluation value for each of the storage batteries 5 a to 5 d after the low-capacity battery setting has been made and cancels the low-capacity battery setting when the acquired degradation evaluation value for each of the storage batteries 5 a to 5 d satisfies a predetermined condition.

[0076] In this way, when the battery system 1 starts up, if there is variation in the degradation evaluation values, for example, full charge capacities, the storage battery with the lowest full charge capacity is designated as a low-capacity battery and is stopped or used less frequently to slow the progression of battery degradation. On the other hand, the operational batteries other than the low-capacity battery are actively used to speed up the progression of battery degradation. Then, when the full charge capacities of the low-capacity battery and the operational battery approach each other and satisfy certain cancellation requirements, the designation of the low-capacity battery is cancelled and the storage battery can be operated in the same way as the other batteries. This makes it possible to quickly reduce variation in full charge capacities at the time of system startup.

[0077] The battery control system 10 according to this embodiment includes a medium-term operation control unit 30 that controls the charging and discharging of the storage batteries 5a to 5d during the medium-term operation period after the low-capacity battery designation is canceled. The medium-term operation control unit 30 includes, for example, a sharing adjustment rate setting unit 33 that calculates a sharing adjustment rate based on the deterioration evaluation value (e.g., SOH) of each storage battery, and a medium-term power command setting unit 34 that sets individual power commands for each storage battery 5a to 5d using the sharing adjustment rate. This makes it possible to suppress variations in the deterioration evaluation value (e.g., SOH) among the storage batteries during the medium-term operation period of the battery system 1, thereby extending the life of the battery system as a whole.

[0078] The battery control system 10 according to this embodiment includes a later-stage operation control unit 40 that controls charging and discharging of the storage batteries 5a to 5d in a later stage of operation after the battery system 1 has satisfied preset later-stage operation conditions. The later-stage operation control unit 40 includes an individual offset power setting unit 44 that calculates an individual offset power Ps(i) for each storage battery 5 using charging rate data for each storage battery 5, and a later-stage power command setting unit 45 that sets an individual power command for each storage battery 5 using the individual offset power Ps(i) for each storage battery 5.

[0079] In this way, the individual offset power Ps is used to set the individual power command for each operating battery, so it is possible to suppress variations in the median SOC value between the storage batteries over time, as shown in Fig. 16. 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.

[0080] In this embodiment, in the later stage of operation, the individual power command is set using the individual offset power Ps(i), but this is not limited to this. For example, the individual power command for each storage battery 5 may be set without using the individual offset power Ps(i). That is, in this case, the individual power command is given by the following formula:

[0081] Pdiv'(i) = {Pall × (1 / N) × α(i)} where α(i) = 1 + (ΔSOH(i) / SOHave)

[0082] Second Embodiment Next, a power supply and demand system, a battery control system, a battery control method, and a battery control program according to a second embodiment of the present disclosure will be described with reference to the drawings. In the first embodiment described above, the post-operation control unit 40 includes an individual offset power setting unit 44, which performs control to reduce the variation in the central value of the state of charge (SOC) among the storage batteries. In contrast, in this embodiment, the state of charge of the entire battery system 1 is adjusted to extend the life of the entire battery system 1.

[0083] For example, each storage battery 5 constituting the battery system 1 includes a power conversion device 7, a cell monitoring unit (CMU) that monitors the degradation state of the battery cells, 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. 17 , in the early stages of operation, charging and discharging may occur around a state of charge (SOC) of 50%, whereas in the later stages of operation, charging and discharging may occur around an SOC of 50% or less. As such, if the central value of the charge / discharge range for the entire battery system 1 decreases, the minimum SOC (SOCmin in FIG. 17 ) may be more likely to reach the lower limit allowed for the storage battery, potentially shortening the battery life.

[0084] Therefore, the post-operation control unit 40a of the battery control system 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. Hereinafter, 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.

[0085] 18 is a functional configuration diagram showing an example of functions provided in the later-stage operation control unit 40a of the battery control system according to this embodiment. As shown in FIG. 18, the later-stage operation control unit 40a according to this embodiment includes an overall offset power setting unit 46, a system required power correction unit 47, and a later-stage power command setting unit 45a.

[0086] The overall offset power setting unit 46 includes an overall average calculation unit 71 and an offset calculation unit 72. The overall average calculation unit 71 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 71 can calculate the overall average charging rate using a method similar to that of the overall average calculation unit 62 of the first embodiment described above. For example, the overall average calculation unit 71 may calculate the average of moving average values ​​calculated for each storage battery as the overall average charging rate. For the entire battery system 1, the maximum charging rate and the minimum charging rate 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. A known technique may be appropriately adopted as the specific method.

[0087] 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.

[0088] The offset calculation unit 72 calculates an overall offset power for bringing the overall average charging rate of the battery system 1 closer to a target charging rate (e.g., 50%). For example, the offset calculation unit 72 calculates the deviation between the overall average charging rate and the target charging rate, and performs proportional-plus-integral control on this deviation to calculate an overall offset power Pg that reduces the deviation to zero. After calculating the overall offset power Pg, the offset calculation unit 72 stores the overall offset power Pg in the storage unit 42. The offset calculation unit 72 updates the overall offset power Pg in the storage unit 42 every time it calculates the overall offset power Pg.

[0089] The system required power correction unit 47 corrects the system required power received from the grid monitoring system 6 using the latest total offset power Pg. For example, the system required power correction unit 47 reads the latest total offset power Pg stored in the storage unit 42 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.

[0090] The system required power correction unit 47 outputs the corrected system required power Pall' to the later power command setting unit 45a. The later power command setting unit 45a acquires the sharing adjustment rate α(i) stored in the memory unit 42, and sets the individual power command Pdiv'(i) for the operating 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 (4):

[0091] Pdiv'(i)={Pall'×(1 / N)×α(i)} (4)

[0092] As a result, each operating battery is given an individual power command that is based on a deterioration evaluation value (e.g., 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.

[0093] As described above, the later operation control unit 40a of the battery control system according to this embodiment includes an overall offset power setting unit 46 that calculates an overall offset power Pg for correcting the system required power, and a system required power correction unit 47 that corrects the system required power Pall using the overall offset power Pg. The later power command setting unit 45a sets individual power commands for each operating battery using the sharing adjustment rate α(i) and the corrected system required power Pall′.

[0094] 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.

[0095] [Modification 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. 19 shows a functional configuration diagram of a post-operation control unit 40b according to Modification 1. As shown in Fig. 19, the overall offset power setting unit 46a includes a representative charging rate determination unit 73 and an offset calculation unit 74.

[0096] The representative charging rate determiner 73 determines an upper limit representative charging rate and a lower limit representative charging rate for the battery system 1 using charging rate data for the battery system 1 over 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. Statistical processing such as moving average may also be used to determine the upper limit representative charging rate and the lower limit representative charging rate.

[0097] The offset calculation unit 74 calculates the difference between the upper representative charging rate and the allowable upper limit of the charging rate (upper limit difference) and the difference between the lower representative charging rate and the allowable lower limit of the charging rate (lower limit difference), and calculates the total 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.

[0098] The overall offset power setting unit 46a according to the first modification makes it possible to control the operational fluctuation range of the charging rate of the entire battery system at about the center between the allowable upper limit 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.

[0099] The post-operation control unit may include the overall offset power setting unit and the individual offset power setting unit described above. In this way, by using the individual offset power and the overall offset power, it is possible to suppress deviation over time in the central value of the SOC of the entire battery system and to suppress deviation in the central value of the SOC among the storage batteries that make up the battery system 1. This can be expected to further extend the life of the battery system 1.

[0100] Third Embodiment Next, a power supply and demand system, a battery control system, a battery control method, and a battery control program according to a third 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. 20 , 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.

[0101] Hereinafter, components common to the battery control system according to the first embodiment will be denoted by the same reference numerals, and explanations thereof will be omitted, and differences will be mainly described. Fig. 21 is a functional configuration diagram showing an example of functions provided in the medium-term operation control unit 30a of the battery control system according to this embodiment. As shown in Fig. 21, in this embodiment, the functions of the sharing adjustment rate setting unit 33a and the medium-term power command setting unit 34a differ from those of the first embodiment described above.

[0102] 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.

[0103] FIG. 22 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. 22 , 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. 22 , +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. 22 , −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. 22, the relationship between the individual power command Pdiv and the differential voltage Vp is expressed by the following equation (5).

[0104] Vp = -a × Pdiv (5) where a = Vmax / Pmax

[0105] When the above formula (5) is converted into a formula for deriving Pdiv, the following formula (6) is obtained: Pdiv=-Vp / a (6)

[0106] As shown in Fig. 22, 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. 22, 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.

[0107] In this embodiment, the sharing adjustment rate setting unit 33a calculates the slope a(i) by using the sharing adjustment rate α(i) of each storage battery in the following equation (7).

[0108] a(i)=a×{1 / α(i)} (7)

[0109] In equation (7), 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 (7), 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).

[0110] After calculating the slope a(i) for each storage battery, the sharing adjustment rate setting unit 33a stores slope information that associates the identification information of each storage battery with the slope in the storage unit 32. Time information and the like may be added to the slope information.

[0111] The medium-term power command setting unit 34a calculates an individual power command Pdiv(i) for each operating 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, it is possible to use, for example, information notified from the battery system 1, more specifically, the power conversion device 7′. Specifically, the medium-term power command setting unit 34a acquires the slope a(i) for each storage battery stored in the storage unit 32, 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 (8):

[0112] Pdiv(i)=-Vp / a(i) (8)

[0113] After setting the individual power command Pdiv(i) for each operating battery, the medium-term power command setting unit 34a 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(i) is performed in each operating battery.

[0114] 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 23. As shown in Figure 23, 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.

[0115] In this way, when the battery system 1a 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.

[0116] FIG. 24 is a functional configuration diagram showing an example of functions included in the later-stage operation control unit 40c according to this embodiment. As shown in FIG. 24, the later-stage operation control unit 40c differs from the first embodiment described above in that it includes a sharing adjustment rate setting unit 43a and a later-stage power command setting unit 45c. Here, similar to the sharing adjustment rate setting unit 33a described above, the sharing adjustment rate setting unit 43a calculates the slope a(i) for each storage battery and stores slope information in the storage unit 42 that associates the identification information of each storage battery with the slope. Here, time information, etc. may be added to the slope information.

[0117] The later-stage power command setting unit 45c sets the individual power command Pdiv'(i) using the individual offset power Ps(i) calculated by the individual offset power setting unit 44. At this time, the individual power command Pdiv'(i) is given by the following equation (9).

[0118] Pdiv'(i)=Pdiv(i)+Ps(i) =-Vp / a(i)+Ps(i) (9)

[0119] Correcting the individual power command Pdiv(i) with the individual offset power Ps(i) corresponds to translating the power command characteristic along the X-axis, as shown in Fig. 25. Therefore, for example, instead of the individual offset power Ps(i), the individual offset power setting unit 44 may store information on the intercept b(i) of the power command characteristic corresponding to the individual offset power Ps(i) in the storage unit 42. This makes it possible to calculate the individual power command Pdiv'(i) based on the information on the slope a(i) and the intercept b(i) when the battery system 1 is connected to the DC link 8.

[0120] The total offset power setting units 46, 46a of the second embodiment described above can also be applied to the post-operation control unit 40c of this embodiment. In this case, the system required power correction unit 47 is omitted, and the total offset power calculated by the total offset power setting units 46, 46a is provided to the AC / DC converter 9 (see FIG. 20), which then performs power control based on the total offset power.

[0121] 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.

[0122] For example, in the above-described embodiments and modifications, the battery control system 10 is described as including the storage units 22, 32, and 42, but there are no particular limitations on the locations where the storage units 22, 32, and 42 are installed. For example, the storage units 22, 32, and 42 may be configured to be accessible by the battery control system 10, and as one example, the storage units may be configured to allow data to be read from and written to via a network.

[0123] In the above-described embodiments and modifications, the battery control system 10 is described with the degradation state evaluation units 21, 31, 41 that evaluate the degradation state of the battery system 1, 1a as an example, but this is not limited thereto. For example, if the battery system 1 has the functions of the degradation state evaluation units 21, 31, 41, the degradation evaluation values ​​evaluated by the degradation state evaluation units 21, 31, 41 may be acquired. If the degradation evaluation values ​​evaluated by the degradation state evaluation units 21, 31, 41 are stored in a storage unit connected via a network, the degradation evaluation values ​​may be acquired as needed from the storage unit. The above-described method for evaluating the degradation state of the storage battery 5 is also an example, and any known technology for evaluating the degradation state (degradation state) of a storage battery may be employed as appropriate.

[0124] 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.

[0125] 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 low-capacity battery setting unit (23) that sets a low-capacity battery to be used less frequently based on a degradation evaluation value relating to the full charge capacity of each of the storage batteries when the battery system is started; an initial power command setting unit (24) that sets individual power commands for the storage batteries so as to reduce the frequency of use of the low-capacity battery compared to operational batteries that are storage batteries other than the low-capacity battery; and a setting cancellation unit (25) that acquires a degradation evaluation value for each of the storage batteries after the low-capacity battery has been set, and cancels the setting of the low-capacity battery when the acquired degradation evaluation value for each of the storage batteries satisfies a predetermined cancellation condition.

[0126] According to the above aspect, when the battery system starts up, a storage battery with a low degradation evaluation value (e.g., full charge capacity) is designated as a low-capacity battery, and the frequency of use of this low-capacity battery is reduced to slow the progression of battery degradation. Meanwhile, the operational batteries other than the low-capacity battery are actively used to accelerate the progression of battery degradation. Then, when the full charge capacities of the low-capacity battery and the operational battery approach each other and satisfy a predetermined cancellation requirement, the designation of the low-capacity battery is cancelled, and the battery can be operated in the same way as the other storage batteries. This makes it possible to quickly reduce the variation in full charge capacity at the time of system startup.

[0127] In the battery control system (10) according to the second aspect of the present disclosure, in the first aspect, the setting cancellation unit (25) cancels the setting of the low-capacity battery when the difference between the deterioration evaluation value of each operational battery and the deterioration evaluation value of the low-capacity battery falls within a predetermined range.

[0128] According to the above aspect, when the deterioration evaluation value of the low-capacity battery and the deterioration evaluation value of the operating battery approach each other and the difference between them falls within a predetermined range, the low-capacity battery setting can be canceled and the battery can be operated in the same way as other storage batteries.

[0129] A battery control system according to a third aspect of the present disclosure, in the first or second aspect, includes a sharing adjustment rate setting unit (33, 33a) that sets a sharing adjustment rate using the deterioration evaluation value of each of the storage batteries, and a medium-term power command setting unit (34, 34a) that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the settings for all of the low-capacity batteries have been canceled by the setting cancellation unit (25).

[0130] According to the above aspect, in the intermediate operation period after all low-capacity batteries have been released, individual power commands for each battery are set based on the sharing adjustment rate set using the deterioration evaluation value of each battery. This makes it possible to suppress variations in the deterioration evaluation value between batteries and extend the life of the battery system as a whole.

[0131] In the battery control system according to the fourth aspect of the present disclosure, in the third aspect described above, the sharing adjustment rate setting unit (33, 33a) calculates a target deterioration evaluation value using the deterioration evaluation value of each of the storage batteries (5), and sets a sharing adjustment rate for each of the storage batteries (5) that brings the deterioration evaluation value of each of the storage batteries (5) closer to the target deterioration evaluation value.

[0132] 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.

[0133] A battery control system according to a fifth aspect of the present disclosure is the battery control system of the fourth aspect described above, and includes a sharing adjustment rate setting unit (33, 33a) that calculates a target deterioration evaluation value using the deterioration evaluation value of each of the storage batteries and sets a sharing adjustment rate for each of the storage batteries by multiplying an adjustment value that brings the deterioration evaluation value of each of the storage batteries closer to the target deterioration evaluation value by an adjustment gain that is set to a value greater than 1, and a medium-term power command setting unit (34, 34a) that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the setting cancellation unit (25) cancels the settings for all of the low-capacity batteries.

[0134] According to the above aspect, the allocation adjustment rate for each storage battery is set by multiplying an adjustment value that brings the deterioration evaluation value of each storage battery closer to the target deterioration evaluation value by an adjustment gain that is set to a value greater than 1, thereby making it possible to quickly bring the deterioration evaluation value of each storage battery closer to the target deterioration evaluation value.

[0135] A battery control system according to a sixth aspect of the present disclosure, in any of the first to fifth aspects, includes a sharing adjustment rate setting unit (43, 43a) that sets a sharing adjustment rate using a deterioration evaluation value of each of the storage batteries (5), and a later-stage power command setting unit (45, 45a, 45b) that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the battery system has satisfied a predetermined later-stage operation condition.

[0136] According to the above aspect, in the later stage of operation, an individual power command for each storage battery is set based on a sharing adjustment rate set using the deterioration evaluation value of each storage battery, which makes it possible to suppress variations in the deterioration evaluation value between the storage batteries and extend the life of the battery system as a whole.

[0137] A battery control system according to a seventh aspect of the present disclosure is the battery control system of the first or second aspect, further comprising: a sharing adjustment rate setting unit (33, 33a) that calculates a target deterioration evaluation value using a deterioration evaluation value of each of the storage batteries (5), and sets a sharing adjustment rate for each of the storage batteries by multiplying an adjustment value that makes the deterioration evaluation value of each of the storage batteries approach the target deterioration evaluation value by an adjustment gain; and a medium-term power command setting unit (33, 33a) that sets an individual power command for each of the storage batteries using the sharing adjustment rate after the setting cancellation unit (25) cancels the settings for all of the low-capacity batteries. and a later-stage power command setting unit (45, 45a, 45b) that sets individual power commands for each of the storage batteries by using the sharing adjustment rate after the battery system has satisfied a preset later-stage operation condition, wherein the sharing adjustment rate setting unit (33, 33a, 43, 43a) sets the sharing adjustment rate used in the mid-term power command setting unit by using an adjustment gain greater than 1, and sets the sharing adjustment rate used in the later-stage power command setting unit by using an adjustment gain set to 1.

[0138] According to the above aspect, in the middle operation stage, the allocation adjustment rate for each storage battery is set by multiplying an adjustment value that brings the degradation evaluation value of each storage battery closer to the target degradation evaluation value by an adjustment gain that is set to a value greater than 1, so that it is possible to quickly bring the degradation evaluation value of each storage battery closer to the target degradation evaluation value. In the later operation stage, the allocation adjustment rate for each storage battery is set by multiplying an adjustment value that brings the degradation evaluation value of each storage battery closer to the target degradation evaluation value by an adjustment gain that is set to 1, so that it is possible to perform control that restricts the operating range of the state of charge (SOC) and voltage of the storage battery compared to the middle operation stage.

[0139] A battery control system according to an eighth aspect of the present disclosure is in any of the first to seventh aspects, and includes an individual offset power setting unit (44) that calculates an individual offset power for each storage battery using charging rate data for each storage battery, and a later-stage power command setting unit (45) that sets an individual power command for each storage battery using the individual offset power for each storage battery after the battery system (1) has satisfied a preset later-stage operation condition, and the individual offset power setting unit (44) includes an individual average calculation unit (61) 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 (62) that calculates an overall average charging rate that serves as a reference for the entire battery system, and an offset calculation unit (63) that calculates, for each storage battery, an individual offset power that brings the individual average charging rate closer to the overall average charging rate.

[0140] According to the above aspect, in the later stage of operation after the battery system has satisfied the preset later stage operation condition, control is performed 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 battery reach the allowable upper and lower limits, and further extend the life of the entire battery system.

[0141] A battery control system according to a ninth aspect of the present disclosure is in any of the first to seventh aspects, and includes: a sharing adjustment rate setting unit (43) that sets a sharing adjustment rate using a deterioration evaluation value of each of the storage batteries (5); an individual offset power setting unit (44) that calculates an individual offset power for each of the storage batteries using charging rate data of each of the storage batteries; and a later-stage power command setting unit (45) that sets an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries and the sharing adjustment rate after the battery system (1) has satisfied a preset later-stage operation condition. The individual offset power setting unit (44) includes: an individual average calculation unit (61) 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 (62) that calculates an overall average charging rate that serves as a reference for the entire battery system; and an offset calculation unit (63) that calculates, for each of the storage batteries, an individual offset power that brings the individual average charging rate closer to the overall average charging rate.

[0142] According to the above aspect, in the later stage of operation after the battery system has satisfied the preset later stage of operation conditions, the individual power command for each storage battery is set using the sharing adjustment rate set using the deterioration evaluation value of each storage battery and the individual offset power set using the charging rate data. This makes it possible to suppress the variation in the deterioration evaluation value between the storage batteries and to suppress the variation in the median SOC value between the storage batteries over time. As a result, it is possible to effectively extend the life of the entire battery system.

[0143] A battery control system according to a tenth aspect of the present disclosure is, in any of the first to ninth aspects, an overall offset power setting unit (46) that calculates an overall offset power for correcting the system required power, a system required power correction unit (47) that corrects the system required power of the battery system using the overall offset power, and a later-stage power command setting unit (45a) that sets individual power commands for each of the storage batteries using the corrected system required power after the battery system has satisfied a predetermined later-stage operation condition, and the overall offset power setting unit (46) includes an overall average calculation unit (71) 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 over a predetermined period, and an offset calculation unit (72) that calculates an overall offset power for approximating the overall average charging rate to a predetermined reference charging rate.

[0144] According to the above aspect, in the later stage of operation after the battery system has satisfied the preset later stage conditions, the system calculates an overall average charging rate, which is the average charging rate of the battery system over a predetermined period, calculates an overall offset power to bring the calculated overall average charging rate closer to a predetermined reference charging rate, corrects the system required power using the calculated overall offset power, and sets individual power commands for each operating battery 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 until the maximum and minimum charging rates of the storage batteries reach their allowable upper and lower limits, thereby effectively extending the life of the entire battery system.

[0145] A battery control system according to an eleventh aspect of the present disclosure is, in any of the first to ninth aspects, an overall offset power setting unit (46a) that calculates an overall offset power for correcting the system required power, a system required power correction unit (47) that corrects the system required power of the battery system (1) using the overall offset power, and a later-stage power command setting unit (45b) that sets individual power commands for each of the storage batteries using the corrected system required power after the battery system has satisfied a predetermined later-stage operation condition, and the overall offset power setting unit (46a) includes: a representative charging rate determination unit (73) 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 (74) that calculates an 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.

[0146] According to the above aspect, in the later stage of operation after the battery system satisfies the preset later stage conditions, an upper representative charging rate, which is a representative value of the upper limit of the battery system's charging rate, and a lower representative charging rate, which is a representative value of the lower limit of the battery system's charging rate, are determined. 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 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, the time until the maximum and minimum charging rates of the storage batteries reach the allowable upper and lower limits can be extended, thereby effectively extending the life of the entire battery system. By using the maximum and minimum charging rates, even if, for example, the charging and discharging of some storage batteries is controlled near the allowable upper limit or near the allowable lower limit, it is possible to evenly distribute the charging and discharging range of the entire battery system between the allowable upper limit and the allowable lower limit.

[0147] A power supply and demand system (100, 100a) according to a twelfth aspect of the present disclosure includes a battery system (1, 1a) having a plurality of storage batteries (5) and a battery control system (10, 10a) described in any one of the first to eleventh aspects.

[0148] A battery control method according to a thirteenth aspect of the present disclosure is a battery control method applied to a battery system (1) having a plurality of storage batteries (5), and is executed by a computer at the start of the battery system by a step (SA4) of setting a low-capacity battery whose frequency of use is reduced based on a deterioration evaluation value relating to the full charge capacity of each of the storage batteries; a step (SA5) of setting individual power commands for the storage batteries so as to reduce the frequency of use of the low-capacity battery compared to operational batteries that are storage batteries other than the low-capacity battery; and a step (SA8) of acquiring a deterioration evaluation value for each of the storage batteries after the low-capacity battery has been set, and canceling the setting of the low-capacity battery when the acquired deterioration evaluation value for each of the storage batteries satisfies a predetermined cancellation condition.

[0149] A battery control program according to a fourteenth aspect of the present disclosure is a program for causing a computer to function as the battery control system (10, 10a) according to any one of the first to eleventh aspects.

[0150] 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: Battery control system 11: CPU 12: Main memory device 13: Secondary memory device 14: Communication interface 15: Input device 16: Display 20: Initial operation control unit 21: Degradation state evaluation unit 22, 32, 42: Memory unit 23: Low-capacity battery setting unit 24: Initial power command setting unit 25: Setting cancellation unit 30, 30a: Mid-term operation control unit 31: Degradation state evaluation unit 33, 33a: Sharing adjustment rate setting unit 34, 34a: Mid-term power command setting unit 40, 40a, 40b, 40c: Post-operation control unit 41: Degradation state evaluation unit 43, 43a: Sharing adjustment rate setting unit 44: Individual offset power setting unit 45, 45a, 45b: Post-operation power command setting unit 46, 46a: Overall offset power setting unit 47: System required power correction unit 50: Control switching unit 61: Individual average calculation unit 62: Overall average calculation unit 63: Offset calculation unit 71: Overall average calculation unit 72: Offset calculation unit 73: Representative charging rate determination unit 74: Offset calculation unit

Claims

1. A battery control system applicable to a battery system having a plurality of storage batteries, comprising: a low-capacity battery setting unit that sets a low-capacity battery to be used less frequently based on a deterioration evaluation value related to the full charge capacity of each of the storage batteries at the start-up of the battery system; an initial power command setting unit that sets individual power commands for the storage batteries so as to reduce the frequency of use of the low-capacity battery compared to operational batteries which are storage batteries other than the low-capacity batteries; and a setting cancellation unit that acquires a deterioration evaluation value of each of the storage batteries after the low-capacity battery has been set, and cancels the low-capacity battery setting when the acquired deterioration evaluation value of each of the storage batteries satisfies a predetermined cancellation condition.

2. A battery control system as described in claim 1, wherein the setting cancellation unit cancels the setting of the low-capacity battery when the difference between the deterioration evaluation value of each operational battery and the deterioration evaluation value of the low-capacity battery falls within a predetermined range.

3. The battery control system of claim 1, further comprising: a sharing adjustment rate setting unit that sets a sharing adjustment rate using a deterioration evaluation value of each of the storage batteries; and a medium-term power command setting unit that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the settings for all of the low-capacity batteries have been released by the setting release unit.

4. A battery control system as described in claim 3, wherein the sharing adjustment rate setting unit calculates a target deterioration evaluation value using the deterioration evaluation value of each of the storage batteries, 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.

5. A battery control system as described in claim 4, comprising: a sharing adjustment rate setting unit that calculates a target deterioration evaluation value using a deterioration evaluation value of each of the storage batteries, and sets a sharing adjustment rate for each of the storage batteries by multiplying an adjustment value that brings the deterioration evaluation value of each of the storage batteries closer to the target deterioration evaluation value by an adjustment gain that is set to a value greater than 1; and a medium-term power command setting unit that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the settings for all of the low-capacity batteries are released by the setting release unit.

6. A battery control system as described in claim 1, comprising: a sharing adjustment rate setting unit that sets a sharing adjustment rate using a deterioration evaluation value of each of the storage batteries; and a later-stage power command setting unit that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the battery system satisfies a preset later-stage operation condition.

7. A battery control system as described in claim 2, comprising: a sharing adjustment rate setting unit that calculates a target deterioration evaluation value using a deterioration evaluation value of each of the storage batteries, and sets a sharing adjustment rate for each of the storage batteries by multiplying an adjustment value that brings the deterioration evaluation value of each of the storage batteries closer to the target deterioration evaluation value by an adjustment gain; a medium-term power command setting unit that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the settings of all of the low-capacity batteries have been released by the setting release unit; and a later-term power command setting unit that sets individual power commands for each of the storage batteries using the sharing adjustment rate after the battery system satisfies a preset later-term operation condition, wherein the sharing adjustment rate setting unit sets the sharing adjustment rate used in the medium-term power command setting unit by using an adjustment gain greater than 1, and sets the sharing adjustment rate used in the later-term power command setting unit by using an adjustment gain set to 1.

8. A battery control system as described in claim 1, comprising: an individual offset power setting unit that calculates an individual offset power for each of the storage batteries using charging rate data for each of the storage batteries; and a later-stage power command setting unit that sets an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries after the battery system has satisfied a preset later-stage operation condition, wherein the individual offset power setting unit comprises: 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 predetermined 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 an individual offset power for each of the storage batteries to bring the individual average charging rate closer to the overall average charging rate.

9. A battery control system as described in claim 1, comprising: a sharing adjustment rate setting unit that sets a sharing adjustment rate using a deterioration evaluation value of each of the storage batteries; an individual offset power setting unit that calculates an individual offset power for each of the storage batteries using charging rate data for each of the storage batteries; and a later-stage power command setting unit that sets an individual power command for each of the storage batteries using the individual offset power for each of the storage batteries and the sharing adjustment rate after the battery system has satisfied a preset later-stage operation condition, wherein the individual offset power setting unit comprises: 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 predetermined 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 an individual offset power for each of the storage batteries to bring the individual average charging rate closer to the overall average charging rate.

10. A battery control system as described in claim 1, comprising: an overall offset power setting unit that calculates an overall offset power for correcting the system required power; a system required power correction unit that corrects the system required power of the battery system using the overall offset power; and a later-stage power command setting unit that sets individual power commands for each of the storage batteries using the corrected system required power after the battery system has satisfied a preset later-stage operation condition, 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 for a predetermined period; and an offset calculation unit that calculates an overall offset power for approximating the overall average charging rate to a predetermined reference charging rate.

11. A battery control system as described in claim 1, comprising: an overall offset power setting unit that calculates an overall offset power for correcting the system required power; a system required power correction unit that corrects the system required power of the battery system using the overall offset power; and a later-stage power command setting unit that sets individual power commands for each of the storage batteries using the corrected system required power after the battery system has satisfied a preset later-stage operation condition, wherein the overall offset power setting unit comprises: a representative charging rate determination unit that determines an upper representative charging rate and a lower representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; and an offset calculation unit that calculates an overall offset power to bring a difference between the difference between the upper representative charging rate and an allowable upper limit of the charging rate and the difference between the lower representative charging rate and an allowable lower limit of the charging rate closer to zero.

12. 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 11.

13. 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 at the start-up of the battery system: setting a low-capacity battery whose frequency of use is reduced based on a deterioration evaluation value relating to the full charge capacity of each of the storage batteries; setting individual power commands for the storage batteries so as to reduce the frequency of use of the low-capacity battery compared to operational batteries which are storage batteries other than the low-capacity batteries; acquiring a deterioration evaluation value of each of the storage batteries after the low-capacity battery has been set, and canceling the low-capacity battery setting when the acquired deterioration evaluation value of each of the storage batteries satisfies a predetermined cancellation condition.

14. A battery control program for causing a computer to function as the battery control system according to any one of claims 1 to 11.

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