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

Abstract

Provided are: a battery control system capable of extending the time until the maximum value and the minimum value of the state-of-charge of a storage battery reach an allowable upper limit value or an allowable lower limit value and further extending the life of the entire battery system; a power supply and demand system provided with the battery control system; a battery control method; and a battery control program. The battery control system is applied to a battery system provided with a plurality of storage batteries and comprises: an overall average calculation unit (81) that calculates an overall average state-of-charge serving as a reference of the entire battery system using state-of-charge data of the plurality of storage batteries in a predetermined period; an offset calculation unit (82) that calculates an overall offset power for bringing the overall average state-of-charge closer to a target state-of-charge; a system request power correction unit that corrects a system request power of the battery system using the overall offset power; and a power command setting unit that sets a power command for each storage battery on the basis of the corrected system request power.

Description

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

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

[0002] Today, in various environments where electricity is used, such as industrial plants, a stable power supply is achieved by providing a storage battery capable of storing electricity in addition to the power supply source in case of an interruption in the power supply from the power supply source or a need for a large local power supply. Because the nature of storage batteries makes it inevitable that they will deteriorate over time, methods for maintaining the storage battery's charge rate at an appropriate state and methods for accurately estimating the lifespan of storage batteries are being studied in order to extend their lifespan.

[0003] Patent Document 1 discloses that an offset power value indicating charging or discharging is determined using the difference between the amount of stored electricity in a storage battery and a target stored electricity amount, which is the target value for the amount of stored electricity in the storage battery at the end of the supply and demand control period of the storage battery, and the charging and discharging of the storage battery is controlled by correcting the power value indicating the amount of charging and discharging of the storage battery using the offset power value.

[0004] International Publication No. 2014 / 076918

[0005] The invention disclosed in Patent Document 1 is a control for preventing the state of charge (SOC) of a storage battery from becoming either 100% or 0% and for maintaining the state of charge of the storage battery at an appropriate level.

[0006] The batteries that make up a battery system are equipped with a power conversion device, a protection system (CMU) that controls each battery, and other devices, and these devices cause power loss. Because the amount of power loss changes over time, the median value of the charge / discharge range for the entire battery system gradually changes. If this condition continues and the median value of the charge / discharge range for the entire battery system rises or falls, the minimum or maximum charge rate of some batteries may easily reach the upper or lower allowable limit of the batteries, potentially shortening the lifespan of the entire battery system.

[0007] The present disclosure aims to provide a battery control system that can extend the time until the maximum and minimum charging rates of a storage battery reach the allowable upper and lower limits, thereby further extending the lifespan of the entire battery system, as well as a power supply and demand system equipped with the same, a battery control method, and a battery control program.

[0008] A battery control system according to some embodiments of the present disclosure is a battery control system applied to a battery system having a plurality of storage batteries, and includes an overall average calculation unit that calculates an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period of time, an offset calculation unit that calculates an overall offset power to bring the overall average charging rate closer to a target charging rate, a system required power correction unit that corrects the system required power of the battery system using the overall offset power, and a power command setting unit that sets a power command for each of the storage batteries based on the corrected system required power.

[0009] A battery control system according to some embodiments of the present disclosure is a battery control system applied to a battery system having a plurality of storage batteries, and includes: a charging rate determination unit that determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system over a predetermined period; an offset calculation unit that calculates an overall offset power to bring closer to zero the difference between the upper limit representative charging rate and an allowable upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally, and the difference between the upper limit representative charging rate and an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally; a system required power correction unit that corrects the system required power of the battery system using the overall offset power; and a power command setting unit that sets a power command for each of the storage batteries based on the corrected system required power.

[0010] A battery control method according to some embodiments of the present disclosure is a battery control method applied to a battery system including a plurality of storage batteries, and includes the steps of: calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for the plurality of storage batteries over a predetermined period; calculating an overall offset power for bringing the overall average charging rate closer to a target charging rate; correcting the system required power of the battery system using the overall offset power; and setting a power command for each storage battery based on the corrected system required power.

[0011] A battery control method according to some embodiments of the present disclosure is a battery control method applied to a battery system including a plurality of storage batteries, and includes the steps of: using charging rate data of the battery system over a predetermined period of time, calculating an overall offset power for bringing the difference between the upper limit of the range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and the difference between the lower limit of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate, closer to zero; correcting the system required power of the battery system using the overall offset power; correcting the system required power of the battery system using the overall offset power; and setting a power command for each of the storage batteries based on the corrected system required power.

[0012] A battery control program according to some embodiments of the present disclosure is a battery control program applied to a battery system having a plurality of storage batteries, and causes a computer to perform the following processes: calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for the plurality of storage batteries over a predetermined period; calculating an overall offset power for bringing the overall average charging rate closer to a target charging rate; correcting the system required power of the battery system using the overall offset power; and setting a power command for each storage battery based on the corrected system required power.

[0013] A battery control program according to some embodiments of the present disclosure is a battery control program applied to a battery system having a plurality of storage batteries, and causes a computer to execute the following processes: a process of determining an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system over a predetermined period; a process of calculating an overall offset power to bring the difference between the upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate and the difference between the lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate closer to zero; a process of correcting the system required power of the battery system using the overall offset power; and a process of setting a power command for each of the storage batteries based on the corrected system required power.

[0014] According to the present disclosure, it is possible to extend the time until the maximum and minimum values ​​of the storage battery's charging rate reach the allowable upper and lower limits, thereby achieving the effect of further extending the life of the entire battery system.

[0015] 1 is a diagram illustrating a schematic configuration of a power supply and demand system according to an embodiment of the present disclosure. FIG. 1 is a diagram illustrating an example of a hardware configuration of a battery control system. FIG. 2 is a functional configuration diagram illustrating an example of functions of a battery control system according to an embodiment of the present disclosure. FIG. 3 is a functional configuration diagram illustrating an example of functions of an overall offset power setting unit according to an embodiment of the present disclosure. FIG. 4 is a diagram for explaining that the center of the charging rate of the entire battery system tends to shift over time. FIG. 5 is an example of a logic circuit diagram for correcting the system required power Pall using the overall offset power according to an embodiment of the present disclosure. FIG. 6 is a diagram for explaining that the center of the charging rate of the entire battery system is aligned by setting an individual power command using the corrected system required power. FIG. 7 is a functional configuration diagram illustrating an example of functions of an overall offset power setting unit according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating a schematic configuration of a power supply and demand system when a battery system is connected to a DC link.

[0016] First Embodiment Hereinafter, one embodiment of a battery control system, a power supply and demand system including the same, a battery control method, and a battery control program according to 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 one 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.

[0017] 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.

[0018] 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, current, and temperature, and a battery management unit (BMU) (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.

[0019] 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.

[0020] 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 the system required power to be requested of the battery system 1 and transmits it to the battery control system 10.

[0021] 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, and a communication interface 14. The battery control system 10 may also include an input device 15 that accepts input from a user, a display 16, and the like. These components are connected to each other via, for example, a bus 18.

[0022] 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).

[0023] 3 is a functional configuration diagram showing an example of functions of the battery control system 10 according to this embodiment. The battery control system 10 evaluates the state of degradation of each storage battery 5 while the battery system 1 is connected to the power grid 2, and controls the charging and discharging of each storage battery 5 using the evaluation results of the state of degradation. Specifically, as shown in FIG. 3 , the battery control system 10 includes a degradation state evaluation unit 20, a data management unit 30, a sharing adjustment rate setting unit 40, a power command setting unit 50, a memory unit 60, a total offset power setting unit 80, and a system required power correction unit 90.

[0024] 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.

[0025] The degradation state evaluation unit 20 performs degradation state evaluation to evaluate the degradation state of the storage battery 5. The degradation state evaluation is performed while the storage battery 5 is connected to the power grid 2. The degradation state evaluation is started when a preset start condition is satisfied. Examples of the start condition include when a predetermined period has passed since the previous degradation state evaluation, when the cumulative operating time since the previous degradation state evaluation reaches a predetermined time, and when a command to start the degradation state evaluation is input by the user. The start condition may be set as a combination of these. The cycle of the degradation state evaluation may be set to be shorter as the degradation evaluation value decreases.

[0026] The data management unit 30 (see FIG. 3 ) stores, for example, the degradation assessment information acquired from the degradation state assessment unit 20 in the storage unit 60. The data management unit 30 stores in the storage unit 60 the sharing adjustment rates of the storage batteries 5 a to 5 d calculated by the sharing adjustment rate setting unit 40 (described later) and the like.

[0027] The sharing adjustment rate setting unit 40 sets a sharing adjustment rate for each of the storage batteries 5a to 5d based on the deterioration evaluation value (SOH) of each of the storage batteries 5a to 5d stored in the memory unit 60. For example, the sharing adjustment rate setting unit 40 calculates a target deterioration evaluation value using the deterioration evaluation values ​​of the storage batteries 5a to 5d that constitute the battery system 1, and sets a sharing adjustment rate for each storage battery that brings the deterioration evaluation value of each of the storage batteries 5a to 5d closer to this target deterioration evaluation value. The target deterioration evaluation value is, for example, an average value of the deterioration evaluation values ​​of the storage batteries 5a to 5d. The memory unit 60 may be configured to store in advance deterioration evaluation information in which identification information of each storage battery 5 is associated with the deterioration evaluation information value.

[0028] 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.

[0029] For example, the sharing adjustment rate setting unit 40 calculates the sharing adjustment rate α(i) using a target degradation evaluation value SOHave, which is the average value of the SOH of the storage batteries 5a to 5d, and each deviation ΔSOH(i) between the target degradation evaluation value SOHave and the SOH(i) of each storage battery 5. As an example, the sharing adjustment rate α(i) is calculated using the following equation (1).

[0030] Sharing adjustment rate α(i) = {1+K(ΔSOH(i) / SOHave)} (1)

[0031] 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.

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

[0033] 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. The adjustment gain K is a value that can be changed as appropriate.

[0034] When the adjustment gain K is set to zero, the power sharing adjustment rate of each of the storage batteries 5a to 5d becomes 1, and in this case, there is no increase or decrease in the power sharing according to SOH(i). In other words, the system required power is allocated equally to each storage battery.

[0035] In the above formula (1), if the SOH(i) of each storage battery 5 is equal to the target degradation evaluation value SOHave, the deviation ΔSOH(i) between the target degradation evaluation value SOHave and the SOH(i) of each storage battery 5 will be zero, and the share adjustment rate of each storage battery 5a to 5d will be 1. In this case, there will be no increase or decrease in the power share according to SOH(i). In other words, the system required power will be allocated equally to each storage battery.

[0036] When the adjustment gain K is set to 1, the sharing adjustment rate α(i) of each of the storage batteries 5a to 5d is expressed by the following equation.

[0037] Sharing adjustment rate α(i) = {1+(ΔSOH(i) / SOHave)} (2)

[0038] If the target deterioration evaluation value SOHave is 50(%) and SOH(1) for i=1 is the same at 50(%), then ΔSOH(1)=50-50=0(%), and therefore the sharing adjustment rate α(1) is expressed by the following formula.

[0039] Sharing adjustment rate α(1)={1+(ΔSOH(1) / SOHave)}=1

[0040] In this case, if SOHave is 50(%) and SOH(2) for i=2 = 100(%) (twice that for i=1), then ΔSOH(2) = 100-50 = 50(%), and therefore the sharing adjustment rate α(2) is expressed by the following formula.

[0041] Sharing adjustment rate α(2)={1+(ΔSOH(2) / SOHave)}=2

[0042] That is, for a storage battery 5 with twice the SOH of the reference storage battery 5, the sharing adjustment rate α is doubled, and the charge / discharge amount during charging / discharging is also doubled. When selected in this way, it is possible to operate the storage batteries so that the behavior of the charging rate is almost the same.

[0043] For example, when a predetermined calculation start condition is satisfied, the sharing adjustment rate setting unit 40 calculates the sharing adjustment rate α(i) and updates each sharing adjustment rate α(i) in the storage unit 60. Here, the predetermined calculation start condition may be, for example, when the degradation state evaluation unit 20 performs a degradation state evaluation, thereby calculating degradation evaluation values ​​for all of the storage batteries 5 a to 5 d, and degradation evaluation information including the degradation evaluation values ​​for these storage batteries 5 a to 5 d is stored in the storage unit 60. The sharing adjustment rate setting unit 40 may update the sharing adjustment rate α(i) when the operation mode of the battery system 1 changes, for example, when a storage battery 5 is suspended.

[0044] After calculating the sharing adjustment rate for each of the storage batteries 5a to 5d, the sharing adjustment rate setting unit 40 outputs sharing adjustment rate information that associates the identification information of each storage battery with the sharing adjustment rate to the data management unit 30 (see FIG. 3). The sharing adjustment rate information may also include time information and the like.

[0045] The power command setting unit 50 calculates an individual power command Pdiv(i) for each operational battery using the sharing adjustment rate α(i) corresponding to each of the batteries 5a to 5d and the system required power Pall obtained from the grid monitoring system 6. Here, the operational battery is an operable battery, in other words, a battery capable of charge / discharge control in response to the system required power Pall. In other words, the batteries for which degradation is evaluated by the degradation state evaluation unit 20 described above are excluded from the operational batteries.

[0046] The power command setting unit 50 acquires the sharing adjustment rate α(i) of each operating storage battery stored in the memory unit 60, and calculates the individual power command for each operating storage battery by using the acquired sharing adjustment rate α(i) and the system required power Pall in the following equation (3).

[0047] Pdiv(i)=Pall×(1 / N)×α(i) (3)

[0048] In the above formula (3), N represents the number of operational batteries. For example, when the degradation state evaluation unit 20 has not performed the degradation state evaluation, the batteries 5a to 5d may be operational batteries, and when the degradation state evaluation is being performed, batteries other than those being evaluated may be operational batteries.

[0049] As can be seen from equation (3), a larger individual power command is set for an operating battery with a high degradation evaluation value (high health) than for an operating battery with a low degradation evaluation value. After allocating an individual power command Pdiv(i) to each operating battery, the power command setting unit 50 transmits the individual power command Pdiv(i) to the power conversion device 7 corresponding to each operating battery. As a result, charge and discharge control according to the individual power command Pdiv is performed in each operating battery.

[0050] The sum of the sharing adjustment rates α(i) of the operating storage batteries is expressed by the following equation (4).

[0051] Σα(i)=Σ{1+K(ΔSOH(i) / SOHave)}=Σ1=N (4)

[0052] The sum of the individual power commands Pdiv(i) for each operating battery is expressed by the following equation (5).

[0053] ΣPdiv(i)=ΣPall×(1 / N)×α(i)=Pall / N×Σα(i) (5)

[0054] Therefore, the sum of the individual power commands Pdiv(i) for each operating battery is expressed by the following equation (6) from equations (4) and (5).

[0055] ΣPdiv(i)=Pall / N×N=Pall (6)

[0056] Therefore, except in cases where charging and discharging according to the individual power command Pdiv(i) is not possible due to limitations of the power converter, etc., the sum of the individual power commands Pdiv(i) for each operating storage battery is determined to match the system required power Pall.

[0057] Each storage battery 5 constituting the battery system 1 is equipped with a power conversion device 7, a protection system (CMU) that controls each storage battery, and the like, and these devices cause power loss. The amount of this power loss changes over time, so the central value of the charge / discharge range for the entire battery system 1 gradually changes. For example, as shown in Figure 5, in the early stages of operation, charge / discharge is performed around a charge rate of 50%, whereas in the middle to late stages of operation, charge / discharge may be performed around a charge rate of 50% or less. In this way, when the central value of the charge / discharge range for the entire battery system decreases, the minimum charge rate (SOC in Figure 5) may be reached. ｍｉｎ ) may be more likely to reach the lower limit of the battery's tolerance, shortening the lifespan of the entire battery system.

[0058] Therefore, the battery control system 10 according to this embodiment has a function for suppressing such changes in the central value of the charging rate of the entire battery system over time.

[0059] Fig. 3 is a functional configuration diagram showing an example of functions provided in the battery control system 10 according to this embodiment. As shown in Fig. 3, the battery control system 10 according to this embodiment includes an overall offset power setting unit 80 and a system required power correction unit 90. Fig. 4 is a functional configuration diagram showing an example of functions provided in the overall offset power setting unit 80. As shown in Fig. 4, the overall offset power setting unit 80 includes an overall average calculation unit 81 and an offset calculation unit 82.

[0060] The overall average calculation unit 81 calculates the overall average charging rate of the battery system 1, for example, using charging rate data of the battery system 1 for a predetermined period. For example, the overall average calculation unit 81 calculates the average of the moving averages calculated for each storage battery as the overall average charging rate. For the entire battery system 1, the maximum and minimum charging rates for the predetermined period may be identified, and the average of these values ​​may be calculated as the overall average charging rate. The overall average charging rate can be calculated by statistically processing the charging rate data of each storage battery for the predetermined period and calculating the median value of the charging rates, and a known technique may be appropriately adopted as the specific method.

[0061] The specific cycle of 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 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 becomes equal to or greater than a predetermined value for the entire battery system.

[0062] The offset calculation unit 82 calculates the total offset power for bringing the total average charging rate of the battery system 1 closer to a target charging rate (e.g., 50%). For example, the offset calculation unit 82 calculates the deviation between the total average charging rate and the target charging rate, and performs proportional-plus-integral control on this deviation to calculate the total offset power that will bring the deviation to zero. After calculating the total offset power Pg, the offset calculation unit 82 outputs the total offset power Pg to the data management unit 30. As a result, the total offset power Pg is stored in the storage unit 60, and this total offset power Pg is updated at predetermined intervals.

[0063] The system required power correction unit 90 corrects the system required power received from the grid monitoring system 6 using the total offset power Pg. For example, the system required power correction unit 90 reads out the total offset power Pg stored in the storage unit 60 and adds the total offset power Pg to the system required power Pall, thereby correcting the 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.

[0064] The system required power corrector 90 outputs the corrected system required power Pall' to the power command setting unit 50. The power command setting unit 50 acquires the sharing adjustment rate α(i) stored in the memory unit 60, and sets an individual power command Pdiv'(i) for the operating storage battery using the acquired sharing adjustment rate α(i) for each storage battery and the corrected system required power Pall'. For example, the individual power command Pdiv'(i) is given by the following equation (7):

[0065] Pdiv'(i)={Pall'×(1 / N)×α(i)} (7)

[0066] As a result, each operational storage battery is given an individual power command that is based on the SOH and that suppresses changes in the central value of the charging rate 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.

[0067] As described above, the battery control system 10 according to this embodiment includes an overall offset power setting unit 80 that calculates an overall offset power Pg for correcting the system required power, and a system required power correction unit 90 that corrects the system required power Pall using the overall offset power Pg. The overall offset power setting unit 80 includes an overall average calculation unit 81 that calculates an overall average charging rate, which is the average charging rate of the battery system 1, using charging rate data of the battery system 1 over a predetermined period, for example, and an offset calculation unit 82 that calculates an overall offset power for bringing the overall average charging rate closer to a predetermined reference charging rate. The power command setting unit 50 sets individual power commands for each operating storage battery using the sharing adjustment rate α(i) and the corrected system required power Pall′.

[0068] (Total Offset Power Calculation Method 1) Next, a specific example of a method for calculating the total offset power Pg will be described. FIG. 6 is an example of a logic circuit diagram for correcting the system required power Pall using the total offset power Pg according to an embodiment of the present disclosure. The total average calculation unit 81 calculates the total average charging rate using charging rate data for each storage battery. For example, each storage battery is assigned a management number, and the total average calculation unit 81 calculates a moving average of the charging rates for each storage battery from the first storage battery to the i-th storage battery. The moving average of the charging rate for each storage battery may be calculated using multiple stages with different calculation conditions. For example, if the specified period for obtaining the charging rates of each storage battery is one week, the calculation conditions for the moving average for the specified period may be two stages: a pre-processing moving average and a post-processing moving average. For example, in the pre-processing moving average, a moving average is calculated for 60 samples with a sampling time of 60 seconds. In other words, in the pre-processing moving average, a moving average of the charging rates for 3,600 seconds (one hour) is calculated using 60 samples x 60 seconds. The calculation result of the pre-processing moving average may be updated every hour. For example, in the post-processing moving average, a moving average is calculated over a sampling time of 3,600 seconds (1 hour) and 168 samples. That is, in the post-processing moving average, a moving average of the charging rate for 604,800 seconds (1 week) is calculated by multiplying 3,600 seconds by 168 samples. The calculation result of the post-processing moving average may be updated every week. In this way, by calculating a moving average over a relatively short predetermined period and using the calculated result to calculate a moving average over a longer predetermined period, the moving average of the charging rate of the storage battery can be accurately calculated.

[0069] Next, the overall average calculation unit 81 calculates the average of the moving averages of the charging rates of the respective storage batteries over a predetermined period (overall average charging rate SOC ＡＬＬＡＶＧ Next, the offset calculation unit 82 calculates the overall average charging rate as the target charging rate SOC ＴＲＧ For example, the offset calculation unit 82 calculates the overall offset power Pg to bring the overall average charging rate SOC closer to the overall average charging rate SOC (for example, 50%). ＡＬＬＡＶＧ and target charging rate SOC ＴＲＧA deviation between this and the power consumption is calculated, and proportional-integral control is performed on this deviation to calculate a total offset power Pg that reduces the deviation to zero. The total offset power Pg may include an initial offset power Pg0 for compensating for power loss in each device included in the battery system 1. Specifically, for example, the total offset power Pg is calculated by the following equation (8). In equation (8), KP1 is a proportional gain in the proportional-integral control, and KI1 is an integral gain in the proportional-integral control.

[0070]

[0071] The offset calculation unit 82 outputs the total offset power Pg calculated by equation (8) to the data management unit 30, and the total offset power Pg is stored in the storage unit 60. Then, the system required power correction unit 90 corrects the system required power Pall' received from the grid monitoring system 6 using the total offset power Pg. Then, the power command setting unit 50 sets the individual power command Pdiv'(i) of the storage battery using the above-mentioned equation (7).

[0072] As described above, the battery control system 10 according to this embodiment calculates the overall offset power Pg for correcting the system required power Pall, and corrects the system required power Pall using the overall offset power Pg. This provides individual power commands that suppress changes over time in the median state of charge of the entire battery system including multiple storage batteries, and enables charge / discharge control of the power conversion device 7 based on these individual power commands. This makes it possible to suppress changes over time in the median state of charge of the entire battery system. As a result, it is possible to lengthen the time until the maximum and minimum state of charge of the storage batteries reach their allowable upper and lower limits, and further extend the life of the entire battery system.

[0073] The overall average calculation unit 81 calculates the moving average of the charging rate for each storage battery and then calculates the overall average charging rate, so that the trend in the change in charging rate can be accurately grasped even in driving patterns where the charging rate changes instantaneously.

[0074] (Calculation Method 2 of Overall Offset Power) In the above description, an example has been described in which a moving average is used to calculate the individual average charging rates of the storage batteries, but other calculation methods may be used. Below, the overall average charging rate is calculated using the maximum charging rate and the minimum charging rate for each storage battery in a predetermined period. For example, the overall average calculation unit 81 calculates the maximum charging rate SOC(i) for each storage battery in a predetermined period. ＭＡＸ and minimum charge rate SOC(i) ＭＩＮ The specified maximum charging rate SOC(i) is determined. ＭＡＸ and minimum charge rate SOC(i) ＭＩＮ The central charging rate SOC(i) is calculated for each battery using ＣＥＮＴＥＲ Calculate.

[0075] The overall average calculation unit 81 calculates the central charging rate SOC(i) for each storage battery. ＣＥＮＴＥＲ The average of the central charging rates is calculated using the above formula, and the calculation result is used as the overall average charging rate SOC ＡＬＬＡＶＧ Specifically, the overall average charging rate SOC is calculated using the following equations (9) to (11): ＡＬＬＡＶＧ First, the maximum charging rate SOC(i) for each storage battery is calculated from equation (9). ＭＡＸ and minimum charge rate SOC(i) ＭＩＮ Using the above, the central charging rate SOC(i) ＣＥＮＴＥＲ Calculate.

[0076]

[0077] Next, the offset calculation unit 82 calculates the central charging rate SOC(i) for each storage battery calculated by the overall average calculation unit 81 using the following equation (10): ＣＥＮＴＥＲ The overall average charge rate SOC is the average of ＡＶＧ Using the above, the overall average charging rate SOC ＡＶＧ and target charging rate SOC ＴＲＧ (for example, 50%).

[0078]

[0079] Next, the offset calculation unit 82 calculates the total offset power Pg using the charging rate deviation ΔSOC calculated by the equation (10) according to the following equations (11) and (12). In the following equation (11), h is the offset power gain, and Q ｎｏｍ is the rated battery capacity, and Δt is the offset period.

[0080]

[0081]

[0082] Then, the system required power correction unit 90 corrects the system required power Pall′ using the total offset power Pg calculated by equation (12). Then, by substituting the corrected system required power Pall′ into the above equation (7), the individual power command Pdiv′(i) corresponding to each storage battery is calculated.

[0083] In this way, the maximum and minimum charging rates for each storage battery are used to calculate the overall offset power, and then the individual power commands corresponding to each storage battery are calculated using the overall offset power. As a result, as shown in FIG. 7 , the central charging rate of each storage battery can be brought closer to the target charging rate.

[0084] As described above, by identifying the maximum and minimum charging rates and calculating the individual and overall average charging rates instead of calculating the moving average of the charging rates of the storage batteries, the overall average charging rate can be calculated with less memory capacity than when calculating the moving average. That is, the calculation cost of the individual and overall average charging rates can be reduced. Furthermore, since the calculation cost is reduced compared to when calculating the moving average of the charging rates of each storage battery, it is possible to quickly respond to changes in the charging rates of the storage batteries.

[0085] (Total Offset Power Calculation Method 3) Below, a method for calculating the overall average charging rate using a maximum moving average charging rate, which is the maximum value of the moving average charging rate for each storage battery in a predetermined period, and a minimum moving average charging rate, which is the minimum value, will be described. The overall average calculation unit 81 identifies the maximum moving average charging rate and the minimum moving average charging rate for each storage battery in the predetermined period, and calculates the central moving average charging rate for each storage battery using the identified maximum moving average charging rate and minimum moving average charging rate. As a method for identifying the maximum moving average and the minimum moving average, for example, the overall average calculation unit 81 may calculate the average of the charging rate in each interval obtained by dividing the predetermined period into a plurality of intervals, and identify the maximum value of the calculated averages as the maximum moving average and the minimum value of the calculated moving averages as the minimum moving average.

[0086] The overall average calculation unit 81 calculates the average of the center moving average charging rates using the center moving average charging rates for each storage battery, and sets the calculation result as the overall average charging rate. Then, using the calculated overall average charging rate in a manner similar to calculation method 1 described above, the system required power and individual power commands corresponding to each battery are calculated.

[0087] As described above, by calculating the individual average charging rate and the overall average charging rate using the maximum moving average charging rate and the minimum moving average charging rate, it is possible to accurately grasp the trend of changes in charging rate even in driving patterns where the charging rate changes instantaneously, while suppressing calculation costs.

[0088] (Method 4 for Calculating Overall Offset Power) A method for calculating an overall average charging rate using the maximum and minimum charging rates for each storage battery in a predetermined period will be described below. For example, the overall average calculation unit 81 identifies the maximum and minimum charging rates for each storage battery in a predetermined period, and further identifies the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates. Then, the overall average charging rate is calculated using the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates.

[0089] The overall average calculation unit 81 calculates the average of the maximum value among the plurality of maximum charging rates and the minimum value among the plurality of minimum charging rates, and sets the calculation result as the overall average charging rate. Then, using the calculated overall average charging rate in a manner similar to calculation method 1 described above, the system required power and individual power commands corresponding to each battery are calculated.

[0090] As described above, the overall average calculation unit 81 calculates the overall average charging rate using the maximum value among the multiple maximum charging rates and the minimum value among the multiple minimum charging rates, thereby making it possible to calculate the overall average charging rate with less memory capacity. That is, the calculation cost of the individual average charging rate and the overall average charging rate can be reduced. Furthermore, since the calculation cost is reduced compared to when calculating a moving average of the charging rate for each storage battery, it is possible to quickly respond to changes in the charging rate of the storage battery.

[0091] Second Embodiment In the first embodiment, the total offset power is calculated using the overall average charging rate of the battery system 1, but this is not limited to this. In this embodiment, a method for setting the total offset power for operating the battery system 1 taking into account the range in which the charging rate of each storage battery can operate normally will be described. FIG. 8 shows a functional configuration diagram of a total offset power setting unit 80a according to the second embodiment. As shown in FIG. 8, the total offset power setting unit 80a includes a charging rate determination unit 83 and an offset calculation unit 84.

[0092] The charging rate determination unit 83 determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system 1 using charging rate data of the battery system 1 for a predetermined period. The upper limit representative charging rate is a representative value treated as the maximum value of the charging rate for each storage battery, and similarly, the lower limit representative charging rate is a representative value treated as the minimum value of the charging rate for each storage battery. In this embodiment, for example, the maximum moving average charging rate is determined as the upper limit representative charging rate, and the minimum moving average is determined as the lower limit representative charging rate. The maximum and minimum moving averages may be determined by dividing the predetermined period into multiple sections, determining the maximum value of the averages of the charging rates in each section as the maximum moving average, and determining the minimum value of the calculated moving averages as the minimum moving average. In this way, using moving averages can achieve the same function as a filter, such as noise removal. Taking into account limitations on the data capacity required for the moving average, a first-order lag filter may be used.

[0093] This example is not limiting, and the maximum charging rate of the battery system 1 may be determined as the upper limit representative charging rate, and the minimum charging rate of the battery system 1 may be determined as the lower limit representative charging rate. The upper limit representative charging rate and the lower limit representative charging rate are not limited to this. For example, the average value of the maximum charging rates of the storage batteries 5a to 5d may be set as the upper limit representative charging rate, and the average value of the minimum charging rates of the storage batteries 5a to 5d may be set as the lower limit representative charging rate. The upper limit representative charging rate and the lower limit representative charging rate may also be determined using statistical processing such as moving average.

[0094] The offset calculation unit 84 calculates the difference between the maximum moving average charging rate and the allowable upper limit of the charging rate (upper limit difference) and the difference between the minimum moving average charging rate and the allowable lower limit of the charging rate (lower limit difference), and calculates the total offset power for bringing the deviation between the upper limit difference and the lower limit difference closer to zero. The offset calculation unit 84 calculates the total offset power, for example, by performing proportional-integral control on the deviation.

[0095] In this embodiment, a state in which the difference between the upper limit differential and the lower limit differential is zero means that the margin of the maximum moving average charging rate relative to the allowable upper limit of the charging rate is equal to the margin of the minimum moving average charging rate relative to the allowable lower limit of the charging rate. According to the overall offset power setting unit 80a of this embodiment, by bringing the difference between the upper limit differential and the lower limit differential closer to zero, it is possible to control the operational fluctuation range of the charging rate of the entire battery system to be approximately midway between the allowable upper limit and the allowable lower limit. This makes it possible to prevent 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 entire battery system.

[0096] The battery control systems 10, 10a according to the first and second embodiments are also applicable to the case where a battery system 1a is connected to a DC link 8, as shown in Fig. 9 . In the power supply and demand system 100a shown in Fig. 9 , the battery system 1a is connected to the DC link 8 via a power conversion device 7' (7a' to 7d') which is a DC / DC converter. The DC link 8 and the substation 3 are connected via an AC / DC converter 9. In this case, the system required power correction unit 90 is omitted, and the total offset power calculated by the total offset power setting unit 80 is provided to the AC / DC converter 9, which then performs power control based on the total offset power.

[0097] The battery control systems 10 and 10a according to the first and second embodiments described above may include an individual offset power setting unit that sets an individual offset power for each storage battery. By adding a configuration that corrects the individual power command for each operating storage battery using the individual offset power in this manner, it is possible to suppress deviation over time of the central value of the state of charge for the entire battery system and to suppress deviation of the central values ​​of the state of charge among the storage batteries that make up the battery system 1.

[0098] 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.

[0099] For example, in each of the above-described embodiments, the battery control system 10, 10a is described as including the storage unit 60, but there are no particular limitations on the location of the storage unit 60. For example, the storage unit 60 may be configured to be accessible by the battery control system 10, 10a, and may be configured to enable reading and writing of data from and to the storage unit via a network, for example.

[0100] (Additional Notes) The battery control system, the power supply and demand system including the same, the battery control method, and the battery control program described in the above-described embodiments can be understood, for example, as follows: A battery control system (10, 10a) according to a first aspect of the present disclosure is a battery control system applied to a battery system (1, 1a) including a plurality of storage batteries (5), and includes an overall average calculation unit (81) that calculates an overall average charging rate serving as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period, an offset calculation unit (82) that calculates an overall offset power for bringing the overall average charging rate closer to a target charging rate, a system required power correction unit (90) that corrects a system required power of the battery system using the overall offset power, and a power command setting unit (50) that sets a power command for each of the storage batteries based on the corrected system required power.

[0101] According to the above aspect, an overall average charging rate, which is the average charging rate of the battery system over a predetermined period, is calculated, an overall offset power is calculated to bring the calculated overall average charging rate closer to a predetermined target charging rate, and the calculated overall offset power is used to correct the system required power. Then, an individual power command for each operating storage battery is set based on the corrected system required power. This makes it possible to suppress changes in the median charging rate of the entire battery system over time. As a result, it is possible to lengthen the time it takes for the maximum and minimum charging rates of the storage batteries to reach their allowable upper and lower limits, and further extend the life of the entire battery system.

[0102] In the battery control system (10, 10a) according to the second aspect of the present disclosure, in the first aspect, the overall average calculation unit (81) calculates the average of the moving averages of the charging rates of each of the storage batteries (5) during the specified period as the overall average charging rate.

[0103] According to the above aspect, by calculating the average of each moving average of the charging rate for each storage battery as the overall average charging rate, it is possible to accurately grasp the trend of changes in the charging rate even in an operating pattern in which the charging rate changes instantaneously.

[0104] In the battery control system (10, 10a) according to the third aspect of the present disclosure, in the first aspect, the overall average calculation unit (81) identifies the maximum and minimum charging rates for each of the storage batteries (5) during the specified period, and calculates the overall average charging rate using the identified maximum and minimum charging rates.

[0105] According to the above aspect, the overall average charging rate can be calculated with a small memory capacity, and therefore the cost of calculating the overall average charging rate can be reduced.

[0106] In the battery control system (10, 10a) according to the fourth aspect of the present disclosure, in the first aspect, the overall average calculation unit (81) calculates a moving average charging rate, which is a moving average of the charging rates of each of the storage batteries (5) during the specified period, and calculates the overall average charging rate using a maximum moving average charging rate, which is the maximum value of each of the moving average charging rates, and a minimum moving average charging rate, which is the minimum value of each of the moving average charging rates.

[0107] According to the above aspect, by calculating the overall average charging rate using the maximum moving average charging rate and the minimum moving average charging rate, it is possible to accurately grasp the trend of changes in the charging rate even in driving patterns in which the charging rate changes instantaneously, while suppressing calculation costs.

[0108] A battery control system (10, 10a) according to a fifth aspect of the present disclosure is a battery control system applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes: a charging rate determination unit (83) that determines an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; an offset calculation unit (84) that calculates an overall offset power for bringing closer to zero a difference between an allowable upper limit value of a range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and a difference between an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate; a system required power correction unit (90) that corrects a system required power of the battery system using the overall offset power; and a power command setting unit (50) that sets a power command for each of the storage batteries based on the corrected system required power.

[0109] According to the above aspect, the maximum and minimum charging rates of the charging rate data are identified, and an overall offset power is calculated to bring the difference between the maximum charging rate and the allowable upper limit of the charging rate and the difference between the minimum charging rate and the allowable lower limit of the charging rate closer to zero. The calculated overall offset power is then used to correct the system required power, and individual power commands for each operating storage battery are set based on the corrected system required power. This makes it possible to suppress changes in the central value of the charging rate of the entire battery system over time. As a result, it is possible to extend the time it takes for the maximum and minimum charging rates of the storage batteries to reach the allowable upper and lower limits, and further extend the life of the entire battery system. By using the maximum and minimum charging rates, for example, even when the charging and discharging control of some storage batteries is performed near the allowable upper limit and 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.

[0110] An electric power supply and demand system (100, 100a) according to a sixth aspect of the present disclosure is, in any of the first to fifth aspects, provided with a sharing adjustment rate setting unit (40) that acquires deterioration assessment information from a memory unit (60) in which deterioration assessment information associated with identification information of the storage batteries and SOH is stored, and sets a sharing adjustment rate using the SOH of the plurality of storage batteries, wherein the power command setting unit uses the sharing adjustment rate to set an individual power command for each of the storage batteries, calculates a target SOH using the SOH of each of the storage batteries constituting the battery system, sets the sharing adjustment rate for each of the storage batteries so as to bring the SOH of each of the storage batteries closer to the target SOH, adjusts the sharing adjustment rate of the storage batteries, and sets an adjustment gain that is changeable according to the deterioration state to 1, and sets the sharing adjustment rate of each of the storage batteries to a value corresponding to the SOH of each of the storage batteries.

[0111] According to the above aspect, it is possible to calculate a sharing adjustment rate according to the SOH of each storage battery and share power by setting the adjustment gain to 1. By sharing power according to the SOH, it is possible to align the amplitude of the state of charge (SOC) of each storage battery.

[0112] An electric power supply and demand system (100, 100a) according to a seventh aspect of the present disclosure includes a battery system (1, 1a) including a plurality of storage batteries, and the battery control system (10, 10a) according to the first or fifth aspect.

[0113] A battery control method according to an eighth aspect of the present disclosure is a battery control method applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes the steps of: calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for the plurality of storage batteries over a predetermined period; calculating an overall offset power for bringing the overall average charging rate closer to a target charging rate; correcting the system required power of the battery system using the overall offset power; and setting a power command for each storage battery based on the corrected system required power.

[0114] A battery control method according to a ninth aspect of the present disclosure is a battery control method applied to a battery system (1, 1a) having a plurality of storage batteries (5), and includes the steps of: determining an upper 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; calculating an overall offset power for bringing the difference between the upper limit representative charging rate and an allowable upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate, and the difference between the lower limit representative charging rate and an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally, closer to zero; correcting the system required power of the battery system using the overall offset power; correcting the system required power of the battery system using the overall offset power; and setting a power command for each of the storage batteries based on the corrected system required power.

[0115] A battery control program according to a tenth aspect of the present disclosure is a battery control program applied to a battery system (1, 1a) having a plurality of storage batteries (5), and causes a computer to execute the following processes: a process of calculating an overall average charging rate that serves as a reference for the entire battery system using charging rate data for the plurality of storage batteries over a predetermined period; a process of calculating an overall offset power for bringing the overall average charging rate closer to a target charging rate; a process of correcting the system required power of the battery system using the overall offset power; and a process of setting a power command for each storage battery based on the corrected system required power.

[0116] A battery control program according to an eleventh aspect of the present disclosure is a battery control program applied to a battery system (1, 1a) having a plurality of storage batteries (5), and causes a computer to execute the following processes: a process for determining an upper limit representative charging rate and a lower limit representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; a process for calculating an overall offset power for bringing the difference between the upper limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the upper limit representative charging rate and the difference between the lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower limit representative charging rate closer to zero; a process for correcting the system required power of the battery system using the overall offset power; and a process for setting a power command for each storage battery based on the corrected system required power.

[0117] DESCRIPTION OF SYMBOLS 1, 1a: Battery system 2: Power system 3: Substation 4: AC link 5 (5a to 5d): Storage battery 6: System monitoring system 7 (7a to 7d): Power conversion device 7' (7a' to 7d'): Power conversion device 8: DC link 9: AC / DC converter 10, 10a: Battery control system 11: CPU 12: Main memory device 13: Secondary memory device 14: Communication interface 15: Input device 16: Display 18: Bus 20: Degradation state evaluation unit 30: Data management unit 40: Sharing adjustment rate setting unit 50: Power command setting unit 60: Memory unit 80, 80a: Overall offset power setting unit 81: Overall average calculation unit 82: Offset calculation unit 83: Charging rate determination unit 84: Offset calculation unit 90: System required power correction unit 100, 100a: Electricity supply and demand system

Claims

1. A battery control system applicable to a battery system having a plurality of storage batteries, comprising: an overall average calculation unit that calculates an overall average charging rate that serves as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period; an offset calculation unit that calculates an overall offset power for bringing the overall average charging rate closer to a target charging rate; a system required power correction unit that corrects the system required power of the battery system using the overall offset power; and a power command setting unit that sets a power command for each of the storage batteries based on the corrected system required power.

2. A battery control system according to claim 1, wherein the overall average calculation unit calculates the average of each moving average of the charging rate of each storage battery during the specified period as the overall average charging rate.

3. A battery control system as described in claim 1, wherein the overall average calculation unit identifies a maximum charging rate and a minimum charging rate for each storage battery during the specified period, and calculates the overall average charging rate using the identified maximum charging rate and minimum charging rate.

4. A battery control system as described in claim 1, wherein the overall average calculation unit calculates a moving average charging rate which is a moving average of the charging rates of each storage battery during the specified period, and calculates the overall average charging rate using a maximum moving average charging rate which is the maximum value of each moving average charging rate and a minimum moving average charging rate which is the minimum value of each moving average charging rate.

5. A battery control system applicable to a battery system having a plurality of storage batteries, comprising: a 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; an offset calculation unit that calculates an overall offset power for bringing closer to zero a difference between an allowable upper limit of a range of charging rates at which the plurality of storage batteries can operate normally and the upper representative charging rate, and a difference between an allowable lower limit of a range of charging rates at which the plurality of storage batteries can operate normally and the lower representative charging rate; a system required power correction unit that corrects a system required power of the battery system using the overall offset power; and a power command setting unit that sets a power command for each of the storage batteries based on the corrected system required power.

6. A battery control system as described in claim 1 or 5, comprising a sharing adjustment rate setting unit that acquires deterioration evaluation information from a memory unit in which deterioration evaluation information associated with identification information and SOH of the storage batteries is stored, and sets a sharing adjustment rate using the SOH of a plurality of the storage batteries, wherein the power command setting unit uses the sharing adjustment rate to set individual power commands for each of the storage batteries, calculates a target SOH using the SOH of each of the storage batteries that constitute the battery system, sets the sharing adjustment rate for each of the storage batteries such that the SOH of each of the storage batteries approaches the target SOH, adjusts the sharing adjustment rate of the storage batteries, and sets an adjustment gain that is changeable according to the deterioration state to 1, and sets the sharing adjustment rate of each of the storage batteries to a value corresponding to the SOH of each of the storage batteries.

7. An electric power supply and demand system comprising: a battery system having a plurality of storage batteries; and the battery control system according to claim 1 or 5.

8. A battery control method applied to a battery system having a plurality of storage batteries, comprising: a step of calculating an overall average charging rate serving as a reference for the entire battery system using charging rate data of the plurality of storage batteries over a predetermined period; a step of calculating an overall offset power for bringing the overall average charging rate closer to a target charging rate; a step of correcting a system required power of the battery system using the overall offset power; and a step of setting a power command for each of the storage batteries based on the corrected system required power.

9. A battery control method applied to a battery system having a plurality of storage batteries, comprising: a step of determining an upper representative charging rate and a lower representative charging rate of the battery system using charging rate data of the battery system for a predetermined period; a step of calculating an overall offset power for bringing closer to zero a difference between an allowable upper limit value of a range of charging rates at which the plurality of storage batteries can operate normally and the upper representative charging rate, and a difference between an allowable lower limit value of the range of charging rates at which the plurality of storage batteries can operate normally and the lower representative charging rate; a step of correcting a system required power of the battery system using the overall offset power; and a step of setting a power command for each of the storage batteries based on the corrected system required power.

10. A battery control program applied to a battery system having a plurality of storage batteries, the battery control program causing a computer to execute the following processes: calculating an overall average charging rate that serves as a benchmark for the entire battery system using charging rate data for a specified period of the plurality of storage batteries; calculating an overall offset power for bringing the overall average charging rate closer to a target charging rate; correcting the system required power of the battery system using the overall offset power; and setting a power command for each of the storage batteries based on the corrected system required power.

11. A battery control program applied to a battery system having a plurality of storage batteries, the battery control program causing a computer to execute the following processes: determining an upper representative charging rate and a lower representative charging rate of the battery system using charging rate data of the battery system for a specified period; calculating an overall offset power for bringing closer to zero the difference between the upper representative charging rate and an allowable upper limit of the range of charging rates at which the plurality of storage batteries can operate normally, and the difference between the upper representative charging rate and an allowable lower limit of the range of charging rates at which the plurality of storage batteries can operate normally, and the difference between the lower representative charging rate and an allowable lower limit of the range of charging rates at which the plurality of storage batteries can operate normally; correcting the system required power of the battery system using the overall offset power; and setting a power command for each of the storage batteries based on the corrected system required power.

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