Method and device for operating power storage system, power storage system, and storage medium

Abstract

The embodiment of the invention relates to an operation method and an operation device of a power storage system, the power storage system, and a storage medium. The present invention addresses the problem of suitably operating a power storage device while suitably reducing the progression of deterioration of the power storage device in a use mode in which a plurality of power storage devices are charged and discharged in an SOC range having a relatively small SOC amplitude. In a method for operating an electricity storage system according to an embodiment, a plurality of SOC ranges that are offset from each other are set, and one of the plurality of SOC ranges that are options for each group is selected as an operating SOC range in a state in which the SOC ranges selected among a plurality of groups are different. In the operating method, the power storage devices belonging to each group are operated within the SOC range selected as the operating SOC range, and the SOC range selected as the operating SOC range is sequentially switched among the plurality of SOC ranges for each group in a state in which the SOC ranges selected among the plurality of groups differ.

Description

Technical Field

[0001] Embodiments of the present invention relate to an operation method and operation device of a power storage system, a power storage system, and a storage medium. Background Art

[0002] In a power storage station, etc., a power storage system having a plurality of power storage devices is used. In the power storage system, each of the plurality of power storage devices has one or more batteries, and the plurality of power storage devices are independent of each other and can transfer power through the power system. In the power storage system, the plurality of power storage devices are operated by transferring power to and from power storage devices, generators, load devices, etc. outside the power storage system through the power system.

[0003] In the power storage system, a plurality of power storage devices are charged and discharged within a relatively small SOC range such as a range below 50% SOC range, depending on the usage, etc. When the charging and discharging of the power storage device is repeated only within a specific SOC range with a relatively small SOC range, the deterioration of the power storage device and the battery used in the power storage device may be accelerated depending on the type of electrode active material used in the battery of the power storage device. In the operation of the power storage system, even in the usage mode in which the power storage devices are charged and discharged separately within the SOC range with a relatively small SOC range, it is required to appropriately reduce the progress of the deterioration of each power storage device. In addition, in the usage mode in which a plurality of power storage devices are charged and discharged separately within the SOC range with a relatively small SOC range, it is required to appropriately operate the power storage system while appropriately reducing the progress of the deterioration of the power storage devices. For example, it is required to appropriately operate the power storage system in a state in which the charging and discharging remaining capacity of the entire power storage system is ensured at any timing. Summary of the invention

[0004] The problem to be solved by the present invention is to provide an operation method and operation device of a power storage system, a power storage system and a storage medium, which can appropriately reduce the progress of degradation of the power storage devices while appropriately operating in a usage mode of charging and discharging multiple power storage devices separately within an SOC range with a relatively small SOC amplitude.

[0005] In an embodiment, in an operation method of an electric storage system having a plurality of electric storage devices, the plurality of electric storage devices are grouped into a plurality of groups, and a plurality of SOC ranges that are shifted from each other are set as options for the operation SOC range of each of the plurality of groups. In the operation method, in a state where the SOC ranges selected are different between the plurality of groups, one of the plurality of SOC ranges that are options for each of the plurality of groups is selected as the operation SOC range, and the electric storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operation SOC range. In the operation method, in a state where the SOC ranges selected are different between the plurality of groups, the SOC range selected as the operation SOC range for each of the plurality of groups is sequentially switched between the plurality of SOC ranges.

[0006] According to the above configuration, it is possible to provide a method and device for operating a power storage system, a power storage system, and a storage medium, which can appropriately operate the power storage system while appropriately reducing the progression of degradation of the power storage device in a usage mode in which multiple power storage devices are charged and discharged separately within an SOC range with a relatively small SOC amplitude. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a block diagram schematically showing an example of a power storage system according to an embodiment.

[0008] Figure 2 This is a schematic diagram showing an example of a plurality of SOC ranges set by a processing circuit of an operation device in the embodiment.

[0009] Figure 3 This is a schematic diagram showing an example of a switching process of switching the SOC range selected as the operation SOC range for each of a plurality of groups, which is performed by the processing circuit of the operation device in the embodiment.

[0010] Figure 4 It means in Figure 3 A schematic diagram showing time changes of an SOC range selected as an operating SOC range in each of a plurality of groups in a switching process of an example.

[0011] Figure 5 This is a flowchart schematically showing an example of processing in operation of the power storage system performed by a processing circuit of the operation device in the embodiment and the like.

[0012] Figure 6 This is a schematic diagram showing the time change of the capacity maintenance rate of the battery capacity of each of the comparative example, Example 1 and Example 2 as the verification result.

[0013] Explanation of symbols

[0014] 1: power storage system, 2: power system, 3: power storage device, 5: battery, 10: application device, 11: processing circuit, 12: storage medium, 15: data management program, 16: application program. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments and the like will be described with reference to the drawings.

[0016] Figure 1 An example of a power storage system 1 according to an embodiment is shown. The power storage system 1 is used in a power storage station or the like, for example, a large-scale power storage system for an electric power system. The power storage system 1 can be connected to the electric power system 2, and can transfer power to and from a device (not shown) outside the power storage system 1 via the electric power system 2. As the electric power system 2, there can be listed a power system that supplies power from a generator that generates power using natural energy such as sunlight and wind power, and a power system that supplies power from a power station, etc. In addition, as devices that transfer power to and from the power storage system 1 via the electric power system 2, there can be listed a power storage device, a generator, and a load device, etc. In a certain example, power from a generator that generates power using natural energy is stored in the power storage system 1 via the electric power system 2. Then, the power storage system 1 supplies the stored power to an external power storage device and a load device, etc., via the electric power system 2.

[0017] The power storage system 1 includes a plurality of power storage devices 3. The plurality of power storage devices 3 can independently transfer power via the power system 2. That is, the plurality of power storage devices 3 can independently connect to the power system 2. Each of the plurality of power storage devices 3 includes one or more batteries 5. Figure 1 In one example, a plurality of batteries 5 are electrically connected in each of the plurality of power storage devices 3. In each of the power storage devices, the plurality of batteries 5 may be electrically connected in series or in parallel. In addition, each of the power storage devices 3 may have both a structure in which the plurality of batteries 5 are electrically connected in series and a structure in which the plurality of batteries 5 are electrically connected in parallel.

[0018] The batteries 5 are, for example, secondary batteries such as lithium-ion secondary batteries. In one example, in each of the power storage devices 3, one or more batteries 5 are respectively composed of battery modules. Then, in each of the battery modules, a plurality of battery cells (single cells) are electrically connected. In each of the battery modules, a plurality of battery cells can be electrically connected in series, and a plurality of battery cells can also be electrically connected in parallel. In addition, in each of the battery modules, both a structure in which a plurality of battery cells are electrically connected in series and a structure in which a plurality of battery cells are electrically connected in parallel can be formed.

[0019] In addition, in each of the power storage devices 3, one or more batteries 5 each have a positive electrode active material and a negative electrode active material as an electrode active material. In one example of the embodiment, lithium iron phosphate (LFP) is used as the positive electrode active material of each of the batteries 5. In this case, as the negative electrode active material of each of the batteries 5, for example, any one of a carbonaceous material, a titanium-containing oxide, and a silicon-based negative electrode material, or a mixed material thereof, is used.

[0020] In each of the power storage devices 3, the charge amount (charge amount) and the SOC value are specified as parameters indicating the charging state. Then, for each of the power storage devices 3, the real-time charge amount is calculated based on the charge amount at a specified time and the time change of the current from the specified time. For example, for each of the power storage devices 3, the real-time charge amount is calculated by adding the time-accumulated value of the current from the specified time to the charge amount at the specified time.

[0021] In addition, in each of the power storage devices 3, a lower limit voltage Vmin and an upper limit voltage Vmax are specified for the voltage. Then, in each of the power storage devices 3, a state in which the voltage during discharge or charge under a specified condition becomes the lower limit voltage Vmin is specified as a state in which the SOC value is 0%, and a state in which the voltage during discharge or charge under a specified condition becomes the upper limit voltage Vmax is specified as a state in which the SOC value is 100%. In addition, in each of the power storage devices 3, a charging capacity (charge amount) in which the SOC value changes from 0% to 100% during charge under a specified condition, or a discharging capacity (discharge amount) in which the SOC value changes from 100% to 0% during discharge under a specified condition is specified as a battery capacity. Then, for each of the power storage devices 3, a ratio of the remaining charge amount (remaining capacity) to the battery capacity until the SOC value is 0% is specified as the SOC value.

[0022] Since the SOC value of each power storage device 3 is defined as described above, the real-time SOC value can be calculated for each power storage device 3 when the power storage device 3 is operated by charging and discharging, etc. In addition, the real-time SOC value of each power storage device 3 can be calculated based on the real-time open circuit voltage of the power storage device 3 based on the relationship between the open circuit voltage of the power storage device 3 and the SOC value.

[0023] In addition, in each of the power storage devices 3, the charge amount (charge amount) and the SOC value are also specified as parameters indicating the charging state for each of the one or more batteries 5 provided in the power storage device 3. In each of the batteries 5, the charge amount and the SOC value are specified in the same manner as the power storage device 3. Then, for each of the batteries 5, the real-time charge amount and the SOC value can be calculated in the same manner as the charge amount and the SOC value in the power storage device 3.

[0024] exist Figure 1 In an example of a power storage system 1, the same number of measuring circuits 6 as the power storage devices 3 are provided, and one measuring circuit 6 is provided for each power storage device 3. Each measuring circuit 6 measures a parameter associated with a corresponding power storage device 3. For example, each measuring circuit 6 measures the current and voltage of a corresponding power storage device 3. In addition, each measuring circuit 6 may also measure the temperature of a corresponding power storage device 3. Therefore, each measuring circuit 6 includes a current measuring circuit for measuring current, and a voltage measuring circuit for measuring voltage, and may also include a temperature sensor for measuring temperature. In addition, each measuring circuit 6 may also measure any one of the current, voltage and temperature of each of more than one battery 5 for a corresponding power storage device 3.

[0025] In each of the measurement circuits 6, parameters related to the corresponding one of the power storage devices 3, such as the current and voltage of the corresponding one of the power storage devices 3, are periodically measured. Therefore, as the measurement result in each of the measurement circuits 6, the time change of the parameter related to the corresponding one of the power storage devices 3 can be obtained, for example, the time change (time history) of the current and voltage in the corresponding one of the power storage devices 3 can be obtained. In addition, in each of the power storage devices 3, when the battery 5 is composed of a plurality of battery cells connected in series, a cell balancer that adjusts the SOC difference between the plurality of battery cells can be introduced into each of the power storage devices 3 together with the measurement circuit 6.

[0026] In addition, in each of the power storage devices 3, when the battery 5 is constructed by connecting a plurality of battery cells in parallel and connecting these parallel-connected parallel battery cells in series, a cell balancer that adjusts the SOC difference between the plurality of parallel battery cells may be introduced into each of the power storage devices 3 together with the measuring circuit 6.

[0027] In addition, in the power storage system 1, the same number of PCS (power conditioning subsystem) 7 as the power storage device 3 is provided as a bidirectional power converter, and one PCS 7 is provided for each power storage device 3. Each PCS 7 performs power conversion on the power from the power system 2 and inputs it to a corresponding one of the power storage devices 3. At this time, each PCS 7 converts the AC power from the power system 2 into DC power in a voltage range corresponding to the power storage device 3 through AC / DC conversion and voltage transformation, and inputs the converted DC power to a corresponding one of the power storage devices 3. Each of the power storage devices 3 is charged by receiving power through a corresponding one of the PCS 7.

[0028] In addition, each PCS 7 performs power conversion on the power from the corresponding one of the power storage devices 3 and outputs it to the power system 2. At this time, each PCS 7 converts the DC power from the corresponding one of the power storage devices 3 into AC power in the voltage range and frequency range corresponding to the power system 2 through DC / AC conversion and transformation, and outputs the converted AC power to the power system 2. Each of the power storage devices 3 outputs power through the corresponding one of the PCS 7 and is discharged.

[0029] In addition, a connection switching circuit 8 is provided in the power storage system 1. The connection switching circuit 8 is provided between each PCS 7 and the power system 2, and can switch the electrical connection state of each power storage device 3 with respect to the power system 2. In the connection switching circuit 8, the electrical connection state with respect to the power system 2 can be switched for each power storage device 3. Thus, the plurality of power storage devices 3 can independently transfer power to and from the power system 2.

[0030] In addition, since the electrical connection state with respect to the power system can be switched for each power storage device 3, a state in which one power storage device 3 is electrically connected to the power system 2 and another power storage device 3 is not electrically connected to the power system 2 can be formed in the power storage system 1 by the connection switching circuit 8. In addition, in the connection switching circuit 8, the electrical connection state of each power storage device 3 with respect to other power storage devices 3 in the power storage system 1 can be switched. Then, in the power storage system 1, electric power can be transferred between the plurality of power storage devices 3 electrically connected by the connection switching circuit 8.

[0031] An operation device 10 is provided in the power storage system 1. The operation device 10 performs processing related to the operation of the power storage system 1, for example, controls the charging and discharging of each of the plurality of power storage devices 3, and manages the SOC range of each operation of the power storage devices 3, that is, the operation SOC range. In one example, the operation device 10 is a processing device (computer) such as a server, and includes a processing circuit 11 and a storage medium 12. The processing circuit 11 is composed of a processor or an integrated circuit, etc. The processor etc. constituting the processing circuit 11 includes any one of a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a microcomputer, an FPGA (Field Programmable Gate Array), and a DSP (Digital Signal Processor). The processing circuit 11 may be composed of one processor etc. or may be composed of a plurality of processors etc. The storage medium 12 is any one of a main storage device such as a memory and an auxiliary storage device. In the operation device 10, only one memory etc. serving as the storage medium 12 may be provided, or a plurality of memories etc. may be provided.

[0032] The processing circuit 11 performs processing by executing a program stored in the storage medium 12. Figure 1 In one example, a data management program 15 and an application program 16 are stored in the storage medium 12 as programs executed by the processing circuit 11. The processing circuit 11 writes data to the storage medium 12 and reads data from the storage medium 12 by executing the data management program 15. In addition, the processing circuit 11 performs the processing related to the operation of the power storage system 1 described later by executing the application program 16. In addition, when the operation device 10 is a processing device such as a server, the power from the power system 2 may be converted by a PCS or the like, and the converted power may be supplied to the processing circuit 11, thereby starting the processing circuit 11.

[0033] In one example, the operation device 10 is composed of a plurality of processing devices (computers) such as a plurality of servers, and the processors of the plurality of processing devices cooperate to perform the processing described below related to the operation of the power storage system 1. In another example, the operation device 10 is composed of a cloud server in a cloud environment. The infrastructure of the cloud environment is composed of virtual processors such as virtual CPUs and cloud storage. Therefore, when the operation device 10 is composed of a cloud server, the virtual processor replaces the processing circuit 11 to perform the processing described below related to the operation of the power storage system 1. Then, the cloud storage has the same function as the storage medium 12 to store programs and data.

[0034] The processing circuit 11 controls the electrical connection state of each power storage device 3 relative to the power system 2 (the connection state of each power storage device 3 and the power system 2) by controlling the respective operations of the PCS7 and the connection switching circuit 8. As a result, the power transfer of each power storage device 3 via the power system 2 is controlled. In addition, the processing circuit 11 controls the electrical connection state of each power storage device 3 relative to other power storage devices 3 in the power storage system 1 by controlling the respective operations of the PCS7 and the connection switching circuit 8. As a result, the power transfer between multiple power storage devices 3 is controlled. Therefore, by controlling the respective operations of the processing circuit 11, the PCS7 and the connection switching circuit 8, the charging and discharging of each power storage device 3 are controlled.

[0035] For example, the operation of the connection switching circuit 8 is controlled by the processing circuit 11, so that each of the power storage devices 3 is switched to a state where power is input and a state where power is output. In addition, in each of the power storage devices 3, in the state where power is input, the operation of a corresponding PCS 7 is controlled by the processing circuit 11, so that the magnitude of the input current, i.e., the charging current, etc., is adjusted. Then, in each of the power storage devices 3, in the state where power is output, the operation of a corresponding PCS 7 is controlled by the processing circuit 11, so that the magnitude of the output current, i.e., the discharge current, etc., is adjusted.

[0036] The processing circuit 11 obtains the measurement results of each of the measuring circuits 6. Therefore, the processing circuit 11 obtains the measurement results of each of the current and voltage for each of the power storage devices 3. Then, based on the measurement results of the current and voltage for each of the power storage devices 3, the processing circuit 11 controls the operation of the PCS 7 and the connection switching circuit 8, and controls the charging and discharging of each of the power storage devices 3. For example, the processing circuit 11 calculates the time change of the current and the time change of the voltage for each of the power storage devices 3 based on the measurement results of the corresponding one of the measuring circuits 6. Then, based on the time change of the current and the time change of the voltage, the processing circuit 11 controls the charging and discharging of each of the power storage devices 3.

[0037] In addition, the processing circuit 11 calculates the real-time SOC value and the time change (time history) of the SOC value for each of the power storage devices 3 using the measurement results of the current and voltage in the corresponding one of the measuring circuits 6. The SOC value of each of the power storage devices 3 is calculated using any of the above methods. Based on the calculation results of the real-time SOC value and the time change of the SOC value for each of the power storage devices 3, the processing circuit 11 controls the operation of the PCS 7 and the connection switching circuit 8, and controls the charging and discharging of each of the power storage devices 3.

[0038] In addition, in a certain example, a user interface (not shown) is provided in the power storage system 1. In this case, in the user interface, operations related to the operation of the power storage system 1 are input by the operation device 10 and the user of the power storage system 1. Therefore, in the user interface, any one of a button, a mouse, a touch panel, and a keyboard is provided as an operation unit for the user to input operations. In addition, a notification unit for notifying information related to the operation of the power storage system 1 is provided in the user interface. In the notification unit, information is notified by any one of a screen display and a sound. In addition, the user interface can be integrated with the processing device constituting the operation device 10, or it can be provided independently of the processing device constituting the operation device 10.

[0039] The following describes the processing performed by the processing circuit 11 and the like of the operating device 10 in the operation of the power storage system 1. The processing shown below is performed by the processing circuit 11 executing the application program 16. In the present embodiment, in the operation of the power storage system 1, the processing circuit 11 and the like group the plurality of power storage devices 3 into a plurality of groups Y. Each of the plurality of grouped groups Y has at least one power storage device 3. In addition, each of the plurality of power storage devices 3 belongs to only one of the plurality of groups Y. The number of groups Y in which the power storage devices 3 are grouped is preferably three or more. In addition, the number of power storage devices 3 belonging to the group Y may be the same among the plurality of groups Y or may be different among the plurality of groups Y. However, in the plurality of grouped groups Y, the number of power storage devices 3 belonging to each other is preferably the same.

[0040] In addition, the processing circuit 11 and the like set a plurality of SOC ranges X that are staggered from each other as options of the operating SOC ranges to be operated for each of the plurality of power storage devices 3. The plurality of SOC ranges X are set as options of the operating SOC ranges of each of the plurality of groups Y grouped as described above. The number of the set SOC ranges X is equal to or greater than the number of the grouped groups Y. In addition, preferably, the plurality of power storage devices 3 are grouped into three or more groups Y, and three or more SOC ranges X are set as options of the operating SOC ranges.

[0041] In each of the plurality of SOC ranges X that are set, a central SOC value ηc, an upper limit SOC value ηu, and a lower limit SOC value ηl are specified. In each of the SOC ranges X, the upper limit SOC value ηu becomes the upper limit of the SOC range, and the lower limit SOC value ηl becomes the lower limit of the SOC range. In addition, in each of the SOC ranges X, the central SOC value ηc becomes the center of the SOC range, and the central SOC value ηc is equivalent to the added average of the upper limit SOC value ηu and the lower limit SOC value ηl. The processing circuit 11 etc. sets the SOC range X in a state where the central SOC value ηc, the upper limit SOC value ηu, and the lower limit SOC value ηl are different among the plurality of SOC ranges X.

[0042] Figure 2 FIG. 2 shows an example of a plurality of SOC ranges X set by the processing circuit 11 of the operation device 10 in the embodiment and the like. Figure 2In one example, three SOC ranges X1 to X3 are set as options for the operation SOC ranges of the plurality of groups Y. The central SOC value ηc2 of the SOC range X2 is lower than the central SOC value ηc1 of the SOC range X1, and the central SOC value ηc3 of the SOC range X3 is higher than the central SOC value ηc1 of the SOC range X1. In addition, the upper limit SOC value ηu2 of the SOC range X2 is lower than the upper limit SOC value ηu1 of the SOC range X1, and the upper limit SOC value ηu3 of the SOC range X3 is higher than the upper limit SOC value ηu1 of the SOC range X1. Then, the lower limit SOC value ηl2 of the SOC range X2 is lower than the lower limit SOC value ηl1 of the SOC range X1, and the lower limit SOC value ηl3 of the SOC range X3 is higher than the lower limit SOC value ηl1 of the SOC range X1.

[0043] Since the SOC range X1 to X3 is set as described above, Figure 2 In one example, the SOC ranges X1 to X3 are offset from each other. Figure 2 In one example, the SOC range X3 becomes the highest SOC range Xmax which is the highest among the set SOC ranges X1 to X3. Then, the SOC range X2 becomes the lowest SOC range Xmin which is the lowest among the set SOC ranges X1 to X3.

[0044] In each of the SOC ranges X set as the options for the operational SOC range, an SOC width Δη corresponding to the width from the upper limit SOC value ηu to the lower limit SOC value ηl is defined. Figure 2 In one example, SOC width Δη1 of SOC range X1, SOC width Δη2 of SOC range X2, and SOC width Δη3 of SOC range X3 are respectively specified. In setting of SOC range X, SOC width Δη may be the same among multiple SOC ranges X, or may be different among multiple SOC ranges X.

[0045] In addition, depending on how the power storage system 1 is used, each of the power storage devices 3 may be charged and discharged within a relatively small SOC range such as a range where the SOC range is 50% or less. In this case, in each of the plurality of SOC ranges X that are options for the operation SOC range, the SOC range Δη is set to a relatively small value, for example, an arbitrary value between 10% and 50%. In one example, in each of the SOC ranges X, the SOC range Δη is set to an arbitrary value between 25% and 35%.

[0046] In a preferred example, the processing circuit 11 and the like set the SOC width Δη to be the same between the plurality of SOC ranges X. In this example, Figure 2When the SOC ranges X1 to X3 are set as in the example of , the SOC widths Δη1 to Δη3 are the same as each other.

[0047] In another preferred example, the processing circuit 11 etc. sets the SOC width Δη to be larger in the lower SOC range among the plurality of SOC ranges X. Figure 2 When the SOC range X1 to X3 is set as in the example of , the SOC width Δη1 becomes larger than the SOC width Δη3 , and the SOC width Δη2 becomes larger than the SOC width Δη1 .

[0048] In a preferred example, a first SOC range Xa and a second SOC range Xb are set as a plurality of SOC ranges X that are options for operating the SOC range, and a central SOC value ηcb of the second SOC range Xb is higher than an upper limit SOC value ηua of the first SOC range Xa. In another preferred example, a first SOC range Xa and a third SOC range Xc are set as a plurality of SOC ranges X that are options for operating the SOC range, and a central SOC value ηcc of the third SOC range Xc is lower than a lower limit SOC value ηla of the first SOC range Xa. In addition, as a plurality of SOC ranges X, it is more preferred that both the second SOC range Xb and the third SOC range Xc are set in addition to the first SOC range Xa.

[0049] For example, suppose Figure 2 The SOC ranges X1 to X3 are set as in an example. In this case, it is preferred that the central SOC value ηc3 of the SOC range X3 is higher than the upper limit SOC value ηu1 of the SOC range X1. In addition, it is preferred that the central SOC value ηc2 of the SOC range X2 is lower than the lower limit SOC value ηl1 of the SOC range X1. Then, it is more preferred that the central SOC value ηc3 is higher than the upper limit SOC value ηu1, and the central SOC value ηc2 is lower than the lower limit SOC value ηl1.

[0050] In a preferred example, in the highest SOC range Xmax, which is the highest among the plurality of SOC ranges X that are options for the operation SOC range, the upper limit SOC value ηumax is set to any SOC value of 95% or more and 100% or less. In another preferred example, in the lowest SOC range Xmin, which is the lowest among the plurality of SOC ranges X, the lower limit SOC value ηlmin is set to any SOC value of 0% or more and 5% or less. In addition, it is more preferred that the upper limit SOC value ηumax of the highest SOC range Xmax is set to any SOC value of 95% or more and 100% or less, and the lower limit SOC value ηlmin of the lowest SOC range Xmin is set to any SOC value of 0% or more and 5% or less.

[0051] For example, suppose Figure 2 The SOC ranges X1 to X3 are set as in an example. In this case, the upper limit SOC value ηu3 of the SOC range X3, which is the highest SOC range Xmax, is preferably set to any SOC value of 95% or more and 100% or less. In addition, the lower limit SOC value ηl2 of the SOC range X2, which is the lowest SOC range Xmin, is preferably set to any SOC value of 0% or more and 5% or less. Then, it is more preferable that the upper limit SOC value ηu3 is set to any SOC value of 95% or more and 100% or less, and the lower limit SOC value ηl2 is set to any SOC value of 0% or more and 5% or less.

[0052] During operation of the power storage system 1, the processing circuit 11 or the like selects (allocates) one of the plurality of SOC ranges X set as described above as the operating SOC range for each of the plurality of groups Y. At this time, the SOC range X selected as the operating SOC range is selected for each of the plurality of groups Y in a state where the SOC ranges X selected are different among the plurality of groups Y.

[0053] Then, the processing circuit 11 and the like operate the power storage devices 3 belonging to each of the plurality of groups Y within the SOC range X selected as the operation SOC range. Therefore, in each of the plurality of groups Y, the charging and discharging of each of the power storage devices 3 is controlled in a state where the SOC value of the power storage device 3 converges to the SOC range X selected as the operation SOC range. In addition, in each of the groups Y, the SOC value of the power storage device 3 that is not being charged or discharged is maintained at any SOC value in the SOC range X selected as the operation SOC range.

[0054] For example, suppose Figure 2 As an example of the ...

[0055] During operation of the power storage system 1, the processing circuit 11 or the like sequentially switches the SOC range X selected as the operation SOC range for each of the plurality of groups Y among the plurality of SOC ranges X set as options. As a result, the SOC range X that becomes the operation SOC range in each of the plurality of groups Y is rotated among the plurality of SOC ranges X. At this time, the SOC range X selected as the operation SOC range for each of the plurality of groups Y is sequentially switched in a state where the SOC ranges X selected among the plurality of groups Y are different.

[0056] In addition, in each of the plurality of groups Y, the order of selection as the operating SOC range is not particularly limited if the SOC range X selected as the operating SOC range is switched sequentially and the SOC range X selected (allocated) in real time is different from that of other groups Y. In addition, in each of the plurality of groups Y, each of the plurality of SOC ranges X that are selected as the operating SOC range may be periodically selected as the operating SOC range or may be non-periodically selected as the operating SOC range.

[0057] Figure 3 An example of a switching process of switching the SOC range X selected as the operation SOC range for each of the plurality of groups Y, which is performed by the processing circuit 11 of the operation device 10 in the embodiment and the like, is shown. Figure 4 Indicated in Figure 3 In the switching process of one example, the SOC range X selected as the operating SOC range in each of the plurality of groups Y changes with time. Figure 4 In each of the three graphs, the horizontal axis represents the grouped group Y, and the vertical axis represents the SOC value. Figure 4 In FIG. 1 , the SOC range X selected as the operational SOC range is indicated by hatching with oblique lines.

[0058] exist Figure 3 as well as Figure 4 In one example, a plurality of power storage devices 3 are grouped into three groups Y1 to Y3. Figure 2 As an example of , SOC ranges X1 to X3 are set as options for operating the SOC range. Figure 3 as well as Figure 4 In one example, for the power storage device 3 belonging to the group Y1, the SOC range is switched in the order of SOC range X1, SOC range X3, SOC range X2, SOC range X1, ... Then, for the power storage device 3 belonging to the group Y2, the SOC range is switched in the order of SOC range X2, SOC range X1, SOC range X3, SOC range X2, ..., and for the power storage device 3 belonging to the group Y3, the SOC range is switched in the order of SOC range X3, SOC range X2, SOC range X1, SOC range X3, ...

[0059] Therefore, in Figure 3 as well as Figure 4 In one example, according to the selection mode in which all the multiple SOC ranges X1 to X3 that are options are sequentially selected as the operating SOC range, the SOC range selected as the operating SOC range is switched for each of the multiple groups Y1 to Y3. Then, in each of the groups Y1 to Y3, each of the multiple SOC ranges X1 to X3 that are options is periodically selected as the operating SOC range, and the number of times it is selected as the operating SOC range is equal among the multiple SOC ranges X1 to X3.

[0060] In the embodiments, each of the plurality of SOC ranges X that are options in each of the plurality of groups Y may be non-periodically selected as the operating SOC range, and the number of times the SOC ranges are selected as the operating SOC range may be unequal among the plurality of SOC ranges X. In the embodiments, the SOC range X that is selected as the operating SOC range may be switched in accordance with a selection mode (allocation mode) in which only a part of the plurality of SOC ranges X that are options are sequentially selected as the operating SOC range for each of the plurality of groups Y. In this case, the SOC range X that is selected as the operating SOC range in each of the plurality of groups Y is sequentially switched, but a part of the SOC range X that is options is not selected as the operating SOC range.

[0061] In one example, Figure 3 as well as Figure 4 , a plurality of power storage devices 3 are grouped into three groups Y1 to Y3, and three SOC ranges X1 to X3 are set as options for the applied SOC ranges. Then, for group Y1, the applied SOC range is switched in the order of SOC range X1, SOC range X3, SOC range X1, SOC range X2, SOC range X1, ..., for group Y2, the applied SOC range is switched in the order of SOC range X2, SOC range X1, SOC range X2, SOC range X3, SOC range X2, ..., and for group Y3, the applied SOC range is switched in the order of SOC range X3, SOC range X2, SOC range X3, SOC range X1, SOC range X3, ....

[0062] Therefore, in this example, all of the multiple SOC ranges X1 to X3 that are options are sequentially selected as the operating SOC range, and the SOC range selected as the operating SOC range is switched for each of the multiple groups Y1 to Y3. However, in this example, in group Y1, the number of times that SOC range X1 is selected as the operating SOC range is greater than the number of times that SOC ranges X2 and X3 are each selected as the operating SOC range. Then, in group Y2, the number of times that SOC range X2 is selected as the operating SOC range is greater than the number of times that SOC ranges X1 and X3 are each selected as the operating SOC range, and in group Y3, the number of times that SOC range X3 is selected as the operating SOC range is greater than the number of times that SOC ranges X1 and X2 are each selected as the operating SOC range.

[0063] In another example, Figure 3 as well as Figure 4 As in an example of the present invention, a plurality of power storage devices 3 are grouped into three groups Y1 to Y3, and three SOC ranges X1 to X3 are set as options for the applied SOC ranges. Then, for group Y1, the applied SOC range is switched in the order of SOC range X1, SOC range X3, SOC range X1, SOC range X3, ..., for group Y2, the applied SOC range is switched in the order of SOC range X2, SOC range X1, SOC range X2, SOC range X1 ..., and for group Y3, the applied SOC range is switched in the order of SOC range X3, SOC range X2, SOC range X3, SOC range X2 ...

[0064] Therefore, in this example, according to the selection mode in which only a part of the multiple SOC ranges X1 to X3 that are options are sequentially selected as the operating SOC range, the SOC range selected as the operating SOC range is switched for each of the multiple groups Y1 to Y3. That is, in group Y1, only SOC ranges X1 and X3 are selected as the operating SOC range, and SOC range X2 is not selected as the operating SOC range. Similarly, in group Y2, only SOC ranges X1 and X2 are selected as the operating SOC range, and SOC range X3 is not selected as the operating SOC range. Then, in group Y3, only SOC ranges X2 and X3 are selected as the operating SOC range, and SOC range X1 is not selected as the operating SOC range.

[0065] In any of the above examples, the SOC range X selected as the operating SOC range is selected and switched for each of the plurality of groups Y in a state where the SOC range X selected is different among the plurality of groups Y. However, in a preferred example of the embodiment, Figure 3 as well as Figure 4In the same example as in the example of FIG. 1 , all of the plurality of SOC ranges X that are options are sequentially selected as the selection mode of the operating SOC range, and the SOC range X selected as the operating SOC range is switched for each of the plurality of groups Y. Then, in a more preferred example, Figure 3 as well as Figure 4 Similarly to one example, in each of the plurality of groups Y, all of the plurality of SOC ranges X that are options are sequentially selected as the operating SOC range, and the number of times they are selected as the operating SOC range is equal among the plurality of SOC ranges X that are options.

[0066] Furthermore, even when the number of the SOC ranges X that are options is greater than the number of the groups Y, as in any of the above examples, the SOC range X selected as the operating SOC range is selected and switched for each of the plurality of groups Y. That is, in a state where the SOC ranges X selected are different among the plurality of groups Y, the SOC range X selected as the operating SOC range is selected and switched for each of the plurality of groups Y.

[0067] In one example, a plurality of power storage devices 3 are grouped into three groups Y1 to Y3, and as an option for the applied SOC range, in addition to the above-mentioned SOC ranges X1 to X3, an SOC range X4 that is offset from any of the SOC ranges X1 to X3 is set. Then, for group Y1, the applied SOC range is switched in the order of SOC range X1, SOC range X2, SOC range X3, SOC range X4, SOC range X1, ..., for group Y2, the applied SOC range is switched in the order of SOC range X2, SOC range X3, SOC range X4, SOC range X1, SOC range X2, ..., and for group Y3, the applied SOC range is switched in the order of SOC range X3, SOC range X4, SOC range X1, SOC range X2, SOC range X3, ....

[0068] In addition, for the central SOC value ηc of the SOC range X selected as the operating SOC range in real time, an average value ηcave in the grouped plurality of groups Y is defined. In a preferred example, the SOC range X that becomes the operating SOC range is selected and switched by the processing circuit 11 or the like in a state where the average value ηcave of the central SOC value ηc of the SOC range X selected as the operating SOC range in real time is 45% or more and 55% or less for each of the plurality of groups Y. Therefore, in this example, in the state where the power storage system 1 is in operation, the average value ηcave of the central SOC values ​​ηc of the plurality of SOC ranges X selected as the operating SOC range is 45% or more and 55% or less at any time.

[0069] For example, suppose Figure 3as well as Figure 4 As an example, the SOC range selected as the operating SOC range is switched in each of groups Y1 to Y3. In this case, regardless of the time, the additive average value ηcave in groups Y1 to Y3 related to the central SOC value ηc of the SOC range selected in real time becomes a value of (ηc1+ηc2+ηc3) / 3. That is, during the period when SOC range X1 in group Y1 becomes the operating SOC range, during the period when SOC range X2 in group Y1 becomes the operating SOC range, and during the period when SOC range X3 in group Y1 becomes the operating SOC range, the additive average value ηcave becomes a value of (ηc1+ηc2+ηc3) / 3. In such a case, Figure 3 as well as Figure 4 As an example, when the SOC range to be the operating SOC range is switched in each of the groups Y1 to Y3, it is preferable to set the optional SOC ranges X1 to X3 so that the value (ηc1+ηc2+ηc3) / 3 becomes 45% or more and 55% or less.

[0070] In addition, in the embodiment, the processing circuit 11 and the like switch the SOC range X that becomes the operating SOC range for each of the plurality of groups Y in a state where the timing of switching the SOC range X that becomes the operating SOC range is synchronized or substantially synchronized among the plurality of groups Y. In a certain example, the processing circuit 11 and the like calculate the elapsed period T from the time when the SOC range X that becomes the operating SOC range was last switched in the plurality of groups Y that are grouped. Then, the processing circuit 11 and the like switch the SOC range X that becomes the operating SOC range for each of the groups Y based on the fact that the elapsed period T becomes longer than the prescribed period Tref. Therefore, the processing circuit 11 and the like switch the SOC range X that becomes the operating SOC range for each of the plurality of groups in response to the fact that the prescribed period Tref has elapsed from the last switching time. The switching of the SOC range X that becomes the operating SOC range based on time information such as the elapsed period T is suitable, for example, when the operation of the power storage device 3 is constant over a year. In addition, the prescribed period Tref is set to an appropriate value in response to the intensity of the operation of the power storage device 3. For example, in the case where charging and discharging are repeated frequently with a large input / output, the predetermined period Tref is set to a shorter period (e.g., one month) than in the case where the input / output is small and the frequency of charging and discharging is also low. Then, in the case where the input / output is small and the frequency of charging and discharging is also low, the predetermined period Tref is set to a longer period (e.g., three months) than in the case where charging and discharging are repeated frequently with a large input / output. In addition, in the case where the switching of the SOC range X selected as the operation SOC range is not performed even once in the group Y, the elapsed period from the start time of the operation of the power storage system 1 is used as the elapsed period T.

[0071] In another example, the processing circuit 11 and the like calculate the integrated value P of the total amount of power input and output to the plurality of power storage devices 3 since the last switching of the SOC range X to the operating SOC range. In this case, the integrated value of the input power (charging power) and the integrated value of the output power (discharging power) are calculated for each power storage device 3, starting from the last switching, and the sum of the integrated value of the input power and the integrated value of the output power is calculated as the integrated value of the amount of power input and output in one power storage device 3. The integrated value of the input power and the integrated value of the output power of each power storage device 3 is calculated based on the time change of the current in the power storage device 3 and the time change of the voltage in the power storage device 3. Then, the integrated value P of the power amount is calculated as the total value of all the plurality of power storage devices 3 in relation to the integrated value of the power amount calculated for each power storage device 3. Switching of the SOC range X to the operating SOC range based on the integrated value of the power amount is suitable, for example, when the operation of the power storage device 3 changes greatly by season or by month.

[0072] In this example, the processing circuit 11 and the like switch the SOC range X to the operating SOC range for each of the groups Y based on the fact that the integrated value P of the electric power amount becomes equal to or greater than the predetermined electric power amount Pref. Therefore, in response to the fact that the integrated value P from the last switching time related to the total input and output electric power amount to the plurality of electric storage devices 3 becomes equal to or greater than the predetermined electric power amount Pref, the processing circuit 11 and the like switch the SOC range X to the operating SOC range for each of the plurality of groups. In addition, in the case where the switching to the SOC range X to be selected as the operating SOC range is not performed even once in the group Y, the integrated value from the start time of the operation of the electric storage system 1 is used as the integrated value P of the electric power amount with respect to the total input and output electric power amount to the plurality of electric storage devices 3.

[0073] Figure 5 An example of processing during operation of the power storage system 1 performed by the processing circuit 11 of the operation device 10 in the embodiment and the like is shown. Figure 5 At the start of the processing of an example of , the processing circuit 11 etc. obtains information related to the grouped multiple groups Y (S51). Thus, the processing circuit 11 etc. obtains information related to how the multiple power storage devices 3 are grouped, and the identifiers of the power storage devices 3 belonging to each of the multiple groups Y. Then, the processing circuit 11 etc. obtains information related to multiple SOC ranges X that are options for the operating SOC ranges of each of the multiple groups Y (S52). The multiple SOC ranges X are set in a state of being offset from each other, and are set in the same way as in any of the above examples.

[0074] Then, the processing circuit 11 etc. selects an SOC range X as the initial operation SOC range from the plurality of SOC ranges X for each of the plurality of groups Y (S53). At this time, in a state where the SOC ranges X selected are different between the plurality of groups Y, the SOC range X selected as the operation SOC range for each of the plurality of groups Y is selected. Then, the processing circuit 11 etc. operates the power storage devices 3 belonging to each of the plurality of groups Y within the selected SOC range X (S54). At this time, for example, the processing circuit 11 etc. controls the charging and discharging of each of the power storage devices 3 belonging to each of the plurality of groups Y in a state where the SOC value of the power storage device 3 converges to the SOC range X selected as the operation SOC range.

[0075] Then, when the operation of the power storage system 1 is continued (S55-Yes), the processing circuit 11 etc. calculates the elapsed period T from the start time of the operation of the power storage system 1 or the last switching time (S56). Then, the processing circuit 11 etc. determines whether the calculated elapsed period T is greater than the prescribed period Tref (S57). When the elapsed period T is shorter than the prescribed period Tref (S57-No), the processing returns to S54, and the processing circuit 11 etc. sequentially performs the processing after S54. Thus, the processing circuit 11 etc. continues to operate the power storage device 3 belonging to each of the plurality of groups Y within the SOC range X selected as the operation SOC range in real time.

[0076] On the other hand, when the elapsed period T is equal to or longer than the predetermined period Tref (S57-Yes), the processing circuit 11 etc. switches the SOC range X selected as the operating SOC range for each of the plurality of groups Y (S58). At this time, the processing circuit 11 etc. switches the SOC range X selected as the operating SOC range for each of the plurality of groups Y in a state where the SOC range X selected is different among the plurality of groups Y. Then, the process returns to S54, and the processing circuit 11 etc. operates the power storage device 3 belonging to each of the plurality of groups Y within the SOC range X newly selected as the operating SOC range.

[0077] In addition, in a certain example, instead of the processing of S56 and S57, the processing circuit 11 and the like calculate the integrated value P of the above-mentioned electric power. Then, the processing circuit 11 and the like determine whether the integrated value P of the calculated electric power is greater than or equal to the prescribed electric power Pref. When the integrated value P of the electric power is less than the prescribed electric power Pref, the processing circuit 11 and the like continue to operate the power storage device 3 belonging to each of the plurality of groups Y within the SOC range X selected as the operating SOC range in real time. On the other hand, when the integrated value P of the electric power is greater than or equal to the prescribed electric power Pref, the processing circuit 11 and the like switch the SOC range X selected as the operating SOC range for each of the plurality of groups Y. Then, the processing circuit 11 and the like operate the power storage device 3 belonging to each of the plurality of groups Y within the SOC range X newly selected as the operating SOC range.

[0078] Here, in a usage mode in which the power storage device 3 is charged and discharged within an SOC range with a relatively small SOC range, such as a range in which the SOC range is 50% or less, when the power storage device 3 is repeatedly charged and discharged within only a specific SOC range, the deterioration of the power storage device 3 and the battery 5 used in the power storage device 3 may be accelerated depending on the type of electrode active material used in the battery 5 of the power storage device 3. For example, in the power storage device 3 formed of the battery 5 using lithium iron phosphate (LFP) as the positive electrode active material, since the power storage device 3 is charged and discharged within only a single SOC range with a relatively small SOC range, the deterioration of the power storage device 3 and the battery 5 tends to accelerate.

[0079] In the present embodiment, for the grouped multiple groups Y, one of the multiple SOC ranges X that are offset from each other is selected as the operating SOC range, and the power storage devices 3 belonging to each of the multiple groups Y are operated within the SOC range X selected as the operating SOC range. Then, for each of the multiple groups Y, the SOC range X selected as the operating SOC range is sequentially switched between the multiple SOC ranges X. Therefore, even when charging and discharging of each of the power storage devices 3 is performed in an SOC range with a relatively small SOC range such as a range of 50% or less, each of the power storage devices 3 is not continuously operated in only a specific SOC range X, but the charging and discharging of each of the power storage devices 3 is performed by sequentially switching the SOC range X. That is, by sequentially switching the operating SOC range between the multiple SOC ranges X, it is effectively prevented that each of the power storage devices 3 is operated only in a specific SOC range. Therefore, even in the usage mode of charging and discharging each of the multiple power storage devices 3 in an SOC range with a relatively small SOC range, the progress of the deterioration of each of the power storage devices 3 is appropriately reduced.

[0080] In addition, in the present embodiment, by sequentially switching the SOC range X to the operating SOC range, the progress of degradation of each of the power storage devices 3 is reduced, so there is no need to interrupt the operation of the power storage system 1 to perform recovery processing of each of the power storage devices 3. For example, in a usage mode in which each of the power storage devices 3 is charged and discharged within an SOC range with a relatively small SOC amplitude, it is not necessary to repeat the charge and discharge cycle between the SOC value of 0% and the SOC value of 100% to perform recovery processing of each of the power storage devices 3. The operation of the power storage system 1 is not interrupted due to the recovery processing, etc., so the power storage system 1 is appropriately used.

[0081] In addition, in the present embodiment, in a state where the SOC range X selected among the plurality of groups Y is different, the SOC range X selected as the operating SOC range is selected for each of the plurality of groups Y. Then, in a state where the SOC range X selected among the plurality of groups Y is different, the SOC range X selected as the operating SOC range is switched for each of the plurality of groups Y. Therefore, at any time, the SOC range X selected as the operating SOC range in the plurality of groups Y is different from each other. Thus, it is effectively prevented that all the groups Y (all the power storage devices 3) are operated in a higher SOC range, and that all the groups Y (all the power storage devices 3) are operated in a lower SOC range. Therefore, at any timing, the power storage system 1 is properly operated to ensure the state of the remaining charge and discharge power in the entire power storage system 1.

[0082] In the present embodiment, a plurality of SOC ranges X are set so that the central SOC value ηc, the upper limit SOC value ηu, and the lower limit SOC value ηl are different among the plurality of SOC ranges X. Therefore, a plurality of SOC ranges X shifted from each other are appropriately set as options for operating the SOC range.

[0083] In one example of the present embodiment, when the average value ηcave of the central SOC value ηc in the SOC range X selected as the operating SOC range is defined as described above, the average value ηcave of the central SOC value ηc is 45% or more and 55% or less at any time. As a result, in the operation of the power storage system 1, it is more effectively prevented that all the groups Y (all the power storage devices 3) are operated in a relatively high SOC range, and that all the groups Y (all the power storage devices 3) are operated in a relatively low SOC range. Therefore, the remaining charge capacity and the remaining discharge capacity of the entire power storage system 1 are appropriately secured at any timing, and the power storage system 1 is further appropriately operated.

[0084] In one example of the present embodiment, in accordance with the selection mode in which all of the plurality of SOC ranges X that are options are sequentially selected as the operating SOC range, the SOC range X selected as the operating SOC range is switched for each of the plurality of groups Y. By performing such processing, each of the power storage devices 3 is operated within all of the plurality of SOC ranges X set as options in a state in which the SOC range X that is the operating SOC range is sequentially switched. As a result, each of the power storage devices 3 is operated within a wide SOC range, and thus the progress of degradation of each of the power storage devices 3 is further appropriately reduced.

[0085] In one example of the present embodiment, in each of the plurality of groups Y, all of the plurality of SOC ranges X that are options are sequentially selected as the operating SOC range, and the number of times they are selected as the operating SOC range is equal among the plurality of SOC ranges X that are options. By performing such processing, all of the plurality of SOC ranges X that are set as options are equally selected (allocated) as the operating SOC range in each of the power storage devices 3. As a result, the progress of degradation of each of the power storage devices 3 is further appropriately reduced.

[0086] In one example of the present embodiment, in addition to the first SOC range Xa, at least one of a second SOC range Xb in which the central SOC value ηcb is higher than the upper limit SOC value ηua of the first SOC range Xa and a third SOC range Xc in which the central SOC value ηcc is lower than the lower limit SOC value ηla of the first SOC range Xa is set as the plurality of SOC ranges X. When the SOC range X is set in this way, the operating SOC range is sequentially switched between the plurality of SOC ranges X for each of the plurality of groups Y, so that each of the power storage devices 3 is operated within a wide SOC range. As a result, the progress of degradation of each of the power storage devices 3 is further appropriately reduced.

[0087] In a more preferred example, in addition to the first SOC range Xa, both the second SOC range Xb and the third SOC range Xc are set as the plurality of SOC ranges X. When the SOC range X is set in this way, by sequentially switching the operating SOC range between the plurality of SOC ranges X for each of the plurality of groups Y, each of the power storage devices 3 can be operated within a wider SOC range. As a result, the progress of deterioration of the power storage device 3 and the battery 5 used in the power storage device 3 is further appropriately reduced.

[0088] In one example of the present embodiment, the upper limit SOC value ηumax of the highest maximum SOC range Xmax among the plurality of SOC ranges X is set to any SOC value of 95% or more and 100% or less. In this case, by sequentially switching the operation SOC range between the plurality of SOC ranges X for each of the plurality of groups Y, each of the power storage devices 3 is operated even in the range of SOC value of 95% or more. As a result, each of the power storage devices 3 can be operated in a wider SOC range, so that the progress of degradation of the power storage devices 3 and the like is further appropriately reduced.

[0089] In one example of the present embodiment, the lower limit SOC value ηlmin of the lowest SOC range Xmin among the plurality of SOC ranges X is set to any SOC value between 0% and 5%. In this case, by sequentially switching the operating SOC range between the plurality of SOC ranges X for each of the plurality of groups Y, each of the power storage devices 3 is operated even in the range of SOC value of 5% or less. As a result, each of the power storage devices 3 can be operated in a wider SOC range, so that the progress of degradation of the power storage devices 3 and the like is further appropriately reduced.

[0090] In a more preferred example, the upper limit SOC value ηumax of the maximum SOC range Xmax is set to any SOC value of 95% or more and 100% or less, and the lower limit SOC value ηlmin of the minimum SOC range Xmin is set to any SOC value of 0% or more and 5% or less. In this case, by sequentially switching the operating SOC range between the plurality of SOC ranges X for each of the plurality of groups Y, each of the power storage devices 3 is operated within both the range of the SOC value of 95% or more and the range of the SOC value of 5% or less. As a result, each of the power storage devices 3 can be operated within a wider SOC range, so that the progress of degradation of the power storage devices 3 and the like is further appropriately reduced.

[0091] In one example of the present embodiment, the SOC width Δη from the upper limit SOC value ηu to the lower limit SOC value ηl is the same among the plurality of SOC ranges X. When the operation SOC range is sequentially switched among the plurality of SOC ranges X and each of the power storage devices 3 is operated, by making the SOC widths Δη the same in the plurality of SOC ranges X, the progress of the deterioration of the power storage device 3 and the battery 5 used in the power storage device 3 is further appropriately reduced.

[0092] In one example of the present embodiment, the lower the SOC range among the plurality of SOC ranges X, the larger the SOC width Δη from the upper limit SOC value ηu to the lower limit SOC value ηl. In each of the power storage devices 3, the voltage decreases as the SOC value decreases. Therefore, by increasing the SOC width Δη as the SOC range decreases, the deviation between the plurality of SOC ranges X is reduced in terms of the amount of electric power when the power storage device 3 is charged with the same current from the lower limit SOC value ηl to the upper limit SOC value ηu. Similarly, by increasing the SOC width Δη as the SOC range decreases, the deviation between the plurality of SOC ranges X is reduced in terms of the amount of electric power when the power storage device 3 is discharged with the same current from the upper limit SOC value ηu to the lower limit SOC value ηl.

[0093] In addition, in the present embodiment, the SOC range X selected as the operating SOC range is switched for each of the plurality of groups Y, with the timing of switching the SOC range X as the operating SOC range being synchronized or substantially synchronized among the plurality of groups Y. Thus, at any time, the SOC range X selected as the operating SOC range is different among the plurality of groups Y.

[0094] In addition, the following verification was performed as a verification associated with the implementation method, etc. In the verification, the battery was used in three modes: the comparative example, Example 1, and Example 2. As the battery, a cylindrical battery cell with a diameter of 26 mm and a height of 650 mm was used. That is, a 26650-type cylindrical battery cell was used as the battery. As the electrode active material of the battery, lithium iron phosphate (LFP) was used for the positive electrode active material, and graphite, a carbonaceous material, was used for the negative electrode active material.

[0095] In addition, in the battery used, the battery capacity at the beginning of use, that is, in the initial state, is 2500mAh. In addition, in the battery, the charge end voltage is 3.6V, and 3.6V is set as the voltage corresponding to the state of SOC value 100%. Then, in the battery, the discharge end voltage is 2.0V, and 2.0V is set as the voltage corresponding to the state of SOC value 0%. In addition, the verification is performed at an ambient temperature of 25°C. In addition, in the verification, the real-time SOC value of the battery is calculated in the same way as the calculation of the SOC value of the power storage device described in the embodiment, etc.

[0096] In the comparative example, only the charge and discharge cycle between SOC value 35% and SOC value 65% with SOC width of 30% was repeated. In one cycle, the battery was charged at a charge rate of 2C from SOC value 35% to SOC value 65%, and discharged at a discharge rate of 2C from SOC value 65% to SOC value 35%. In addition, in the comparative example, the battery was discharged to SOC value 0% at a discharge rate of 0.3C every 50 cycles. Then, after charging from SOC value 0% to SOC value 35% at a charge rate of 0.3C, the next cycle was started.

[0097] In the first embodiment, an SOC range Xα between a lower limit SOC value of 10% and an upper limit SOC value of 40% with an SOC width of 30%, an SOC range Xβ between a lower limit SOC value of 22.5% and an upper limit SOC value of 52.5% with an SOC width of 30%, an SOC range Xγ between a lower limit SOC value of 47.5% and an upper limit SOC value of 77.5% with an SOC width of 30%, and an SOC range Xε between a lower limit SOC value of 60% and an upper limit SOC value of 90% with an SOC width of 30% are set. Then, one of the SOC ranges Xα, Xβ, Xγ, and Xε is selected as the operating SOC range, and the battery is operated.

[0098] In the operation of the battery, a charge and discharge cycle between the lower limit SOC value and the upper limit SOC value of the SOC range selected as the operation SOC range was performed. In one cycle, the battery was charged at a charge rate of 2C from the lower limit SOC value to the upper limit SOC value, and the battery was discharged at a discharge rate of 2C from the upper limit SOC value to the lower limit SOC value.

[0099] In Example 1, the SOC range selected as the operating SOC range is switched between the SOC ranges Xα, Xβ, Xγ, and Xε every 50 cycles. Then, the operating SOC range is switched every 50 cycles in the order of Xα→Xβ→Xγ→Xε→Xγ→Xβ→Xα, and the switching of the operating SOC range every 50 cycles in the above order is repeated. In addition, in Example 1, the battery is discharged to an SOC value of 0% at a discharge rate of 0.3C every 50 cycles. Then, after charging from an SOC value of 0% to the lower limit SOC value of the next cycle at a charging rate of 0.3C, the next cycle is started.

[0100] In Example 2, four SOC ranges Xα, Xβ, Xγ, and Xε are set in the same manner as in Example 1. Then, one of the SOC ranges Xα, Xβ, Xγ, and Xε is selected as the operating SOC range, and the battery is operated. In Example 2, in the operation of the battery, a charge and discharge cycle between the lower limit SOC value and the upper limit SOC value of the SOC range selected as the operating SOC range is also performed. Then, in one cycle, the battery is charged at a charging rate of 2C from the lower limit SOC value to the upper limit SOC value, and the battery is discharged at a discharge rate of 2C from the upper limit SOC value to the lower limit SOC value.

[0101] In Example 2, unlike Example 1, the SOC range selected as the operating SOC range is switched between the SOC ranges Xα, Xβ, Xγ, and Xε every 25 cycles. Then, the operating SOC range is switched every 25 cycles in the order of Xα→Xβ→Xγ→Xε→Xγ→Xβ→Xα, and the switching of the operating SOC range every 25 cycles in the above order is repeated. In Example 2, the battery is discharged to an SOC value of 0% at a discharge rate of 0.3C every 25 cycles. Then, after charging from the SOC value of 0% to the lower limit SOC value of the next cycle at a charging rate of 0.3C, the next cycle is started.

[0102] In addition, in each of the comparative example, Example 1, and Example 2, the battery capacity of the battery was measured at each of multiple times while the battery was used as described above. Then, for each time when the battery capacity was measured, the capacity maintenance rate of the battery capacity relative to the battery capacity (2500mAh) in the initial state was calculated, and the time change of the capacity maintenance rate of the battery capacity was calculated. In the measurement of the battery capacity of the battery, the battery was charged to an SOC value of 100% at a charging rate of 0.1C. Then, the battery was discharged at a discharge rate of 0.1C from an SOC value of 100% to an SOC value of 0%, and the discharge capacity from an SOC value of 100% to an SOC value of 0% was measured as the battery capacity of the battery.

[0103] In addition, in each of the comparative example, embodiment 1 and embodiment 2, the cumulative value of the discharge amount of the battery from the start of the battery operation (the start of the first cycle) is calculated at the time when the battery capacity is measured. Then, for each time when the battery capacity is measured, the equivalent cycle value is calculated as the value obtained by dividing the cumulative value of the discharge amount of the battery by the battery capacity (2500mAh) in the initial state. The equivalent cycle value is equivalent to the value indicating how many cycles (how many times) the charge and discharge cycle between the SOC value 0% and the SOC value 100% has been performed when the SOC range is 100%.

[0104] Figure 6 As verification results, the time changes of the capacity maintenance rate of the battery capacity in each of the comparative example, the first embodiment, and the second embodiment are shown. Figure 6 In the figure, the horizontal axis represents the equivalent cycle value, and the vertical axis represents the capacity maintenance rate of the battery capacity. Figure 6 , the change in the capacity maintenance rate of Example 1 is represented by a solid line and a circle, the change in the capacity maintenance rate of Example 2 is represented by a dotted line and a triangle, and the change in the capacity maintenance rate of the comparative example is represented by a single-point dashed line and a square.

[0105] like Figure 6As shown in the figures, in each of Example 1 and Example 2, even when the equivalent cycle value becomes 2000 or more, the capacity maintenance rate of the battery capacity is maintained at 95% or more. On the other hand, in the comparative example, when the equivalent cycle value becomes about 1000, the capacity maintenance rate of the battery capacity is less than 85%. Moreover, when the equivalent cycle value becomes about 1500, the capacity maintenance rate of the battery capacity is less than 80%.

[0106] The above verification confirmed that, in a battery using lithium iron phosphate as the positive electrode active material, the battery deterioration progresses faster when charging and discharging are continued only in one SOC range with a relatively small SOC amplitude. In addition, it was confirmed that, even when the SOC amplitudes of multiple SOC ranges are relatively small, the battery deterioration progresses appropriately by switching the SOC range selected as the operating SOC range in sequence between multiple SOC ranges that are staggered from each other.

[0107] In addition, the above verification confirmed that, in a storage device formed of a battery using lithium iron phosphate as a positive electrode active material, when charging and discharging are continuously performed only in one SOC range with a relatively small SOC amplitude, the deterioration of the storage device accelerates. In addition, it was confirmed that, even when the SOC amplitudes of multiple SOC ranges are relatively small, the deterioration of the storage device is appropriately reduced by sequentially switching the SOC range selected as the operating SOC range between multiple SOC ranges that are staggered from each other.

[0108] In at least one of the above-mentioned embodiments or examples, in a state where the SOC ranges selected between the multiple groups are different, one of the multiple SOC ranges that are options is selected as the operating SOC range for each of the multiple groups, and the power storage devices belonging to each of the multiple groups are operated within the SOC range selected as the operating SOC range. Then, in a state where the SOC ranges selected between the multiple groups are different, the SOC range selected as the operating SOC range for each of the multiple groups is sequentially switched between the multiple SOC ranges. Thus, it is possible to provide an operation method, an operation device, an operation program, and a power storage system for a power storage system, which can appropriately operate the power storage devices while appropriately reducing the progress of degradation of the power storage devices in a usage mode in which each of the multiple power storage devices is charged and discharged within an SOC range with a relatively small SOC amplitude.

[0109] In addition, the above-mentioned embodiments can be summarized as the following technical solutions.

[0110] Technical Solution 1

[0111] A method of operation is a method of operating a power storage system having a plurality of power storage devices, comprising:

[0112] grouping the plurality of power storage devices into a plurality of groups, and setting a plurality of SOC ranges that are shifted from each other as options for operating SOC ranges of the respective plurality of groups;

[0113] In a state where the selected SOC ranges differ among the plurality of groups, one of the plurality of SOC ranges to be the options is selected as the operating SOC range for each of the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operating SOC range; and

[0114] In a state where the SOC ranges selected are different among the plurality of groups, the SOC range selected as the operation SOC range is sequentially switched between the plurality of SOC ranges for each of the plurality of groups.

[0115] Technical Solution 2

[0116] The operation method according to claim 1, wherein, in accordance with a selection mode in which all of the plurality of SOC ranges serving as the options are sequentially selected as the operation SOC range, the SOC range selected as the operation SOC range is switched for each of the plurality of groups.

[0117] Technical Solution 3

[0118] The operation method according to claim 1 or 2, wherein the plurality of SOC ranges to be the options are set in a state where each of a central SOC value, an upper limit SOC value, and a lower limit SOC value is different among the plurality of SOC ranges.

[0119] Technical Solution 4

[0120] An application method as described in Technical Solution 3, wherein, when the additive average value of the multiple groups is specified for the central SOC value of the SOC range selected as the operating SOC range, the SOC range to be the operating SOC range is selected and switched for each of the multiple groups with the additive average value being greater than 45% and less than 55%.

[0121] Technical Solution 5

[0122] An application method as described in Technical Solution 3 or 4, wherein, in the setting of the multiple SOC ranges, a first SOC range is set, and at least one of a second SOC range in which the central SOC value is higher than the upper limit SOC value of the first SOC range, and a third SOC range in which the central SOC value is lower than the lower limit SOC value of the first SOC range is set.

[0123] Technical Solution 6

[0124] An application method as described in any one of technical solutions 3 to 5, wherein, in setting the multiple SOC ranges, the SOC range from the upper limit SOC value to the lower limit SOC value is made the same between the multiple SOC ranges.

[0125] Technical Solution 7

[0126] An application method as described in any one of technical solutions 3 to 5, wherein, in the setting of the multiple SOC ranges, the lower the SOC range among the multiple SOC ranges, the larger the SOC range from the upper limit SOC value to the lower limit SOC value.

[0127] Technical Solution 8

[0128] An application method as described in any one of technical solutions 3 to 7, wherein, in the setting of the multiple SOC ranges, the upper limit SOC value of the highest maximum SOC range among the multiple SOC ranges is set to any SOC value greater than 95% and less than 100%, and the lower limit SOC value of the lowest minimum SOC range among the multiple SOC ranges is set to any SOC value greater than 0% and less than 5%.

[0129] Technical Solution 9

[0130] An operating method as described in any one of technical solutions 1 to 8, wherein the SOC range that becomes the operating SOC range is switched and selected as the SOC range for each of the plurality of groups in a state where the timing of switching the SOC range that becomes the operating SOC range is synchronized among the plurality of groups.

[0131] Technical Solution 10

[0132] An application method as described in any one of technical solutions 1 to 9, wherein the multiple power storage devices each having one or more batteries using lithium iron phosphate as the positive electrode active material are grouped into the multiple groups, and the power storage devices belonging to each of the multiple groups are operated within the SOC range selected as the operating SOC range.

[0133] Technical Solution 11

[0134] An application device,

[0135] It is an operating device of an electric storage system having a plurality of electric storage devices, wherein:

[0136] A processor is provided, the processor being:

[0137] The plurality of power storage devices are grouped into a plurality of groups, and a plurality of SOC ranges that are shifted from each other are set as options for operating SOC ranges of the plurality of groups.

[0138] In a state where the SOC ranges selected are different among the plurality of groups, one of the plurality of SOC ranges to be the options is selected as the operating SOC range for each of the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operating SOC range,

[0139] In a state where the SOC ranges selected are different among the plurality of groups, the SOC range selected as the operation SOC range is sequentially switched between the plurality of SOC ranges for each of the plurality of groups.

[0140] Technical Solution 12

[0141] A power storage system comprising:

[0142] The application device described in technical solution 11; and

[0143] The plurality of power storage devices are grouped into the plurality of groups by the processor of the operation device, and the plurality of power storage devices are operated within the SOC range selected as the operation SOC range in the group to which they belong by the processor.

[0144] Technical Solution 13

[0145] A power storage system as described in technical solution 12, wherein:

[0146] Each of the plurality of power storage devices includes at least one battery.

[0147] In each of the plurality of power storage devices, each of the one or more batteries includes lithium iron phosphate as a positive electrode active material.

[0148] Technical Solution 14

[0149] A storage medium stores an application program for an electric storage system having a plurality of electric storage devices, wherein the application program causes a computer to:

[0150] The plurality of power storage devices are grouped into a plurality of groups, and a plurality of SOC ranges that are shifted from each other are set as options for operating SOC ranges of the plurality of groups.

[0151] In a state where the SOC ranges selected are different among the plurality of groups, one of the plurality of SOC ranges to be the options is selected as the operating SOC range for each of the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operating SOC range,

[0152] In a state where the SOC ranges selected are different among the plurality of groups, the SOC range selected as the operation SOC range is sequentially switched between the plurality of SOC ranges for each of the plurality of groups.

[0153] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are included in the scope and purpose of the invention, and are included in the invention described in the claims and their equivalents.

Claims

1. A method of using a power storage system having a plurality of power storage devices, comprising: grouping the plurality of power storage devices into a plurality of groups, and setting a plurality of SOC ranges that are shifted from each other as options for operating SOC ranges of the respective plurality of groups; In a state where the selected SOC ranges are different among the plurality of groups, one of the plurality of SOC ranges as the options is selected as the operating SOC range for each of the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operating SOC range; as well as In a state where the SOC ranges selected are different among the plurality of groups, the SOC range selected as the operation SOC range is sequentially switched between the plurality of SOC ranges for each of the plurality of groups.

2. The method of claim 1, wherein: In accordance with a selection pattern in which all of the plurality of SOC ranges serving as the options are sequentially selected as the operational SOC range, the SOC range selected as the operational SOC range is switched for each of the plurality of groups.

3. The method of claim 1, wherein: The plurality of SOC ranges to be the options are set in a state where each of a central SOC value, an upper limit SOC value, and a lower limit SOC value is different among the plurality of SOC ranges.

4. The method of claim 3, wherein: When the arithmetic average of the plurality of groups is specified for the central SOC value of the SOC range selected as the operating SOC range, the SOC range to be the operating SOC range is selected and switched for each of the plurality of groups in a state where the arithmetic average becomes 45% or more and 55% or less.

5. The method of claim 3, wherein: In setting the plurality of SOC ranges, a first SOC range is set, and at least one of a second SOC range in which the central SOC value is higher than the upper limit SOC value of the first SOC range and a third SOC range in which the central SOC value is lower than the lower limit SOC value of the first SOC range is set.

6. The method of claim 3, wherein: In setting the plurality of SOC ranges, the SOC width from the upper limit SOC value to the lower limit SOC value is made the same among the plurality of SOC ranges.

7. The method of claim 3, wherein: In setting the plurality of SOC ranges, the lower the SOC range among the plurality of SOC ranges, the greater the SOC width from the upper limit SOC value to the lower limit SOC value.

8. The method of claim 3, wherein: In the setting of the multiple SOC ranges, at least one of setting the upper limit SOC value of the highest SOC range among the multiple SOC ranges to any SOC value greater than 95% and less than 100% and setting the lower limit SOC value of the lowest SOC range among the multiple SOC ranges to any SOC value greater than 0% and less than 5%.

9. The operation method according to any one of claims 1 to 8, wherein: The SOC range to be the operational SOC range is switched and selected for each of the plurality of groups in a state where the timing of switching the SOC range to be the operational SOC range is synchronized among the plurality of groups.

10. The operation method according to any one of claims 1 to 8, wherein: The plurality of power storage devices each including one or more batteries using lithium iron phosphate as a positive electrode active material are grouped into the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within an SOC range selected as the operation SOC range.

11. An operating device, comprising: an operating device of an electric storage system having a plurality of electric storage devices; A processor is provided, the processor being The plurality of power storage devices are grouped into a plurality of groups, and a plurality of SOC ranges that are shifted from each other are set as options for operating SOC ranges of the plurality of groups. In a state where the SOC ranges selected are different among the plurality of groups, one of the plurality of SOC ranges to be the options is selected as the operating SOC range for each of the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operating SOC range, In a state where the SOC ranges selected are different among the plurality of groups, the SOC range selected as the operation SOC range is sequentially switched between the plurality of SOC ranges for each of the plurality of groups.

12. A power storage system comprising: The application device according to claim 11; and The plurality of power storage devices are grouped into the plurality of groups by the processor of the operation device, and the plurality of power storage devices are operated within the SOC range selected as the operation SOC range in the group to which they belong by the processor.

13. The power storage system according to claim 12, wherein: Each of the plurality of power storage devices includes at least one battery. In each of the plurality of power storage devices, each of the one or more batteries includes lithium iron phosphate as a positive electrode active material.

14. A storage medium storing an application program for an electric storage system having a plurality of electric storage devices, wherein the application program causes a computer to: The plurality of power storage devices are grouped into a plurality of groups, and a plurality of SOC ranges that are shifted from each other are set as options for operating SOC ranges of the plurality of groups. In a state where the SOC ranges selected are different among the plurality of groups, one of the plurality of SOC ranges to be the options is selected as the operating SOC range for each of the plurality of groups, and the power storage devices belonging to each of the plurality of groups are operated within the SOC range selected as the operating SOC range, In a state where the SOC ranges selected are different among the plurality of groups, the SOC range selected as the operation SOC range is sequentially switched between the plurality of SOC ranges for each of the plurality of groups.

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