Power storage system control device, power storage system, power storage system control method, and program

Abstract

This power storage system control device is for a power storage system in which a plurality of storage battery units are connected in parallel, each of the storage battery units having a storage battery and a DC / DC converter for converting a voltage of charge / discharge power for the storage battery. The control device comprises: an acquisition unit that acquires limit value information related to an input power limit value and an output power limit value which are set for each of the storage batteries of the plurality of storage battery units; and a charge / discharge control unit that charges, with the power discharged from at least one storage battery unit among the plurality of storage battery units, storage batteries of the remaining other storage battery units among the plurality of storage battery units, on the basis of the input power limit value and the output power limit value which are set for each of the storage batteries.

Description

Control device for power storage system, power storage system, control method for power storage system, and program

[0001] This disclosure relates to a control device for a power storage system, a power storage system, a control method for a power storage system, and a program. This application claims priority to Japanese Patent Application No. 2023-132210, filed on August 15, 2023, the contents of which are incorporated herein by reference.

[0002] Energy storage systems are used in various facilities, such as power generation facilities and factories that use renewable energy. The energy storage systems include a plurality of storage battery units, each having a storage battery and a DC / DC converter. The output of a storage battery tends to decrease when the temperature is low. For this reason, Patent Document 1 discloses a control device for a power storage system including a plurality of energy storage devices, which controls the temperature caused by heat generation due to the internal resistance of a first energy storage device by controlling the conduction rate of a bidirectional DC / DC converter provided between a first energy storage device and a second energy storage device based on the SOC (State of Charge) of the energy storage device.

[0003] Japanese Patent Application Publication No. 2015-125880

[0004] However, in a power storage system including multiple storage battery units, the performance and capacity of the storage batteries (hereinafter, sometimes referred to as the characteristics of the storage battery) may differ among the multiple storage batteries, for example, due to the degree of deterioration from a new state or the combination with used batteries with different performance and capacity. Therefore, even if the SOC (state of charge) of the storage battery, which indicates the state of charge of the storage battery, is the same among the multiple storage batteries, if the characteristics of the storage battery are different, the input and output power of the storage battery will differ. Therefore, the difference between the target temperature of the storage battery commanded by the control device and the actual temperature of the storage battery may vary depending on the state of the storage battery. Therefore, efficient temperature control is desirable even when multiple storage batteries with different characteristics are used in combination.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a control device for a power storage system, a power storage system, a control method for a power storage system, and a program that can efficiently control the temperature of multiple storage batteries and quickly reach a target temperature.

[0006] In order to solve the above problems, the control device, power storage system, control method, and program for a power storage system according to the present disclosure are a control device for a power storage system in which a plurality of storage battery units, each having a storage battery and a DC / DC converter that converts the voltage of charging and discharging power to and from the storage battery, are connected in parallel, and include an acquisition unit that acquires limit value information regarding an input power limit value and an output power limit value set for each of the storage batteries of the plurality of storage battery units, and a charge / discharge control unit that charges the storage batteries of the remaining storage battery units of the plurality of storage battery units with power discharged from the storage battery of at least one of the plurality of storage battery units based on the input power limit value and output power limit value set for each of the storage batteries.

[0007] The power storage system according to the present disclosure includes a plurality of storage battery units each having a storage battery and a DC / DC converter that converts the voltage of the charging / discharging power for the storage battery, and the above-described power storage system control device.

[0008] The control method for a power storage system according to the present disclosure is a control method for a power storage system in which a plurality of storage battery units, each having a storage battery and a DC / DC converter that converts the voltage of charging / discharging power to / from the storage battery, are connected in parallel, and includes the steps of: acquiring limit value information regarding an input power limit value and an output power limit value set for each of the storage batteries of the plurality of storage battery units; and charging the storage batteries of the remaining storage battery units among the plurality of storage battery units with power discharged from the storage battery of at least one of the plurality of storage battery units based on the input power limit value and output power limit value set for each of the storage batteries.

[0009] The program disclosed herein causes a control device of a power storage system in which multiple storage battery units, each having a storage battery and a DC / DC converter that converts the voltage of charging and discharging power to and from the storage battery, are connected in parallel to execute the steps of acquiring limit value information regarding input power limit values ​​and output power limit values ​​set for each of the storage batteries of the multiple storage battery units, and charging the storage batteries of the remaining storage battery units of the multiple storage battery units with power discharged from the storage battery of at least one of the multiple storage battery units based on the input power limit value and output power limit value set for each of the storage batteries.

[0010] According to the power storage system control device, power storage system, power storage system control method, and program of the present disclosure, it is possible to efficiently control the temperatures of a plurality of storage batteries and quickly reach a target temperature.

[0011] 1 is a diagram illustrating an overall configuration of a power storage system according to an embodiment of the present disclosure; FIG. 2 is a block diagram illustrating a functional configuration of a control device of the power storage system; FIG. 3 is a diagram illustrating an example of input power limit values ​​and output power limit values ​​set for a plurality of storage batteries according to an embodiment of the present disclosure; FIG. 4 is a diagram illustrating an example of a combination selected based on the sum of the input power limit values ​​of the first storage battery group and the sum of the output power limit value of the second storage battery group when a plurality of storage batteries are divided into a first storage battery group and a second storage battery group according to an embodiment of the present disclosure; FIG. 5 is a diagram illustrating an example of a storage battery that will be the discharging side and a storage battery that will be the charging side based on the selected combination according to an embodiment of the present disclosure; and FIG. 6 is a flowchart illustrating an example of processing by a control device.

[0012] Hereinafter, embodiments for implementing a power storage system control device, a power storage system, a power storage system control method, and a program according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to only this embodiment. (Overall Configuration of Power Storage System) Fig. 1 is a diagram showing the overall configuration of a power storage system according to one embodiment. As shown in Fig. 1, the power storage system 1 includes a control device 3, a DC bus 4, and a plurality of storage battery units 5.

[0013] The power storage system 1 is connected to an external power supply source 7 and an external power supply target 8. The power supply source 7 is, for example, a solar power generation system, a generator, etc. The power supply source 7 is not limited to a solar power generation system, a generator, etc., and may also be an external power system. The external power supply target 8 is, for example, a device that consumes power supplied from the power storage system 1. The external power supply target 8 may also be an external power system.

[0014] The power storage system 1 may include a PCS (Power Conditioning System) 2 between the external power supply source 7 and the power supply target 8. The PCS is a power conditioner that is interconnected with the power supply source 7 and the power supply target 8. The PCS has a bidirectional inverter that converts AC power and DC power. The PCS converts DC power discharged from each storage battery unit 5 into AC power and outputs it to the external power supply target 8. The PCS 2 also converts AC power supplied from the external power supply target 8 into DC power and outputs it to each storage battery unit 5.

[0015] The control device 3 controls the charging and discharging of each storage battery unit. The specific functional configuration of the control device 3 will be described later.

[0016] The DC bus 4 is a bus for connecting an external power supply source 7, a power supply target 8, and a plurality of storage battery units 5.

[0017] The plurality of storage battery units 5 are connected in parallel via the DC bus 4. In this embodiment, for example, four storage battery units 5 are provided in parallel. The number of storage battery units 5 is not limited to four and can be changed as appropriate.

[0018] Each storage battery unit 5 includes a DC / DC converter 51 , a storage battery 52 , and a storage battery controller 55 .

[0019] The DC / DC converter 51 converts the voltage of the charging / discharging power for the storage battery 52 in accordance with instructions from the control device 3. The DC / DC converter 51 converts the power supplied from the external power supply source 7 to a predetermined voltage and charges the storage battery 52. ​​The DC / DC converter 51 also converts the discharging power of the storage battery 52 to a predetermined voltage and supplies it to the external power supply target 8.

[0020] The storage batteries 52 included in each of the plurality of storage battery units 5 may have different degrees of deterioration from a new state of the storage batteries 52 among the plurality of storage battery units 5. Specifically, for example, the characteristics of the storage batteries 52, such as the usage time from a new state, capacity, and performance, may be different among the plurality of storage battery units 5.

[0021] The battery controller 55 monitors the state of each battery 52. ​​For example, the battery controller 55 monitors the terminal output (output voltage, output current) of each battery 52 and the temperature of each battery 52. ​​The battery controller 55 outputs information indicating the state of each battery 52 to the control device 3.

[0022] The battery controller 55 also sets an input power limit value and an output power limit value for each battery 52. ​​Here, the input power limit value is the maximum power (kW) that can be input (charged) to each battery 52. ​​The output power limit value is the maximum power (kW) that can be output (discharged) from each battery 52. ​​The battery controller 55 sets the input power limit value and output power limit value for each battery 52 from preset map information or the like based on the terminal output and temperature of each battery 52. ​​The battery controller 55 sets the input power limit value and output power limit value at predetermined time intervals. The battery controller 55 outputs the set input power limit value and output power limit value to the control device 3.

[0023] (Functional Configuration of Control Device) Fig. 2 is a block diagram showing the functional configuration of a control device according to an embodiment. As shown in Fig. 2, the control device 3 includes a processor 31, a memory 32, a storage 33, and a communication interface 34.

[0024] The processor 31 operates according to a predetermined program to function as an acquisition unit 311 and a charge / discharge control unit 312 .

[0025] The acquisition unit 311 acquires, from the storage battery controller 55, storage battery-related information D1 (see FIG. 2 ) indicating the state of each storage battery 52 in the multiple storage battery units 5. The storage battery-related information D1 includes limit value information, terminal voltage, temperature, etc., for the storage battery 52. ​​The limit value information for the storage battery 52 is information regarding the input power limit value and output power limit value set for each storage battery 52 in the multiple storage battery units 5. In this embodiment, the information regarding the input power limit value and output power limit value may be the input power limit value and output power limit value themselves. Furthermore, the information regarding the input power limit value and output power limit value may be information that is used as a basis for calculating the input power limit value and output power limit value on the control device 3 side, such as limit values ​​of the current input to and output from the storage battery 52.

[0026] FIG. 3 is a diagram illustrating an example of input power limit values ​​and output power limit values ​​set for multiple storage batteries. The storage battery information D1 acquired by the acquisition unit 311 includes, for example, the input power limit value and output power limit value of each storage battery 52 set by the storage battery controller 55, as shown in FIG. 3 . In the example of FIG. 3 , of the four storage battery units 5 shown in FIG. 1 , the storage battery 52A (represented as “A” in FIGS. 3 to 5 ) of the first storage battery unit 5A has an input power limit value of 25 kW and an output power limit value of 25 kW. The storage battery 52B (represented as “B” in FIGS. 3 to 5 ) of the second storage battery unit 5B has an input power limit value of 20 kW and an output power limit value of 15 kW. The storage battery 52C (represented as “C” in FIGS. 3 to 5 ) of the third storage battery unit 5C has an input power limit value of 20 kW and an output power limit value of 25 kW. The storage battery 52D (denoted as "D" in FIGS. 3 to 5) of the fourth storage battery unit 5D has an input power limit value of 15 kW and an output power limit value of 30 kW.

[0027] Here, when at least one of the multiple storage battery units 5 is outputting power to an external power supply target 8, the acquisition unit 311 acquires the amount of power being output to the outside from the storage battery 52. ​​Furthermore, when at least one of the multiple storage battery units 5 is receiving power input from an external power supply source 7, the acquisition unit 311 acquires the amount of power being input to the storage battery 52 from the outside.

[0028] The charge / discharge control unit 312 adjusts the temperature of the storage batteries 52 by performing charging and discharging among the storage batteries 52 of the multiple storage battery units 5. The charge / discharge control unit 312 charges the power discharged from the storage battery 52 of at least one storage battery unit 5 among the multiple storage battery units 5 into the storage batteries 52 of the remaining storage battery units 5 among the multiple storage battery units 5.

[0029] The charge / discharge control unit 312 performs charging / discharging among the storage batteries 52 of the multiple storage battery units 5 based on the input power limit value and output power limit value set for each of the storage batteries 52. Based on the input power limit value and output power limit value set for each of the storage batteries 52, the charge / discharge control unit 312 selects, from the multiple storage battery units 5, the storage battery 52 of at least one storage battery unit 5 to be the charging side and the storage batteries 52 of the remaining storage battery units 5 to be the discharging side.

[0030] 4 is a diagram illustrating an example of combinations selected based on the sum of the input power limit value of the first storage battery group G1 and the sum of the output power limit value of the second storage battery group G2 when multiple storage batteries are divided into a first storage battery group G1 and a second storage battery group G2. As illustrated in FIG. 4 , the charge / discharge control unit 312 generates multiple combinations by dividing the storage batteries into a first storage battery group G1 including the storage batteries 52 of at least one storage battery unit 5 and a second storage battery group G2 including the storage batteries 52 of the remaining storage battery units 5. Here, the first storage battery group G1 is a group of one or more candidate storage batteries to be the charging side. The second storage battery group G2 is a group of the remaining candidate storage batteries to be the discharging side. The storage batteries 52 of all storage battery units 5 are divided to belong to either the first storage battery group G1 or the second storage battery group G2. In this embodiment, the charge / discharge control unit 312 divides, for example, the storage batteries 52 of the four storage battery units 5 in this embodiment into a first storage battery group G1 and a second storage battery group G2, two by two.

[0031] The number of storage batteries 52 belonging to the first storage battery group G1 and the number of storage batteries 52 belonging to the second storage battery group G2 may be the same or different. For example, in this embodiment, four storage battery units 5 are provided. For example, the storage battery 52 of one of the four storage battery units 5 may belong to the first storage battery group G1, and the storage batteries 52 of the remaining three of the four storage battery units 5 may belong to the second storage battery group G2. Furthermore, for example, the storage batteries 52 of two of the four storage battery units 5 may belong to the first storage battery group G1, and the storage batteries 52 of the remaining two of the four storage battery units 5 may belong to the second storage battery group G2. Furthermore, for example, the first storage battery group G1 may include the storage batteries 52 of three of the four storage battery units 5, and the second storage battery group G2 may include the storage battery 52 of the remaining storage battery unit 5 of the four storage battery units 5. The charge / discharge control unit 312 may generate the first storage battery group G1 and the second storage battery group G2 using all of the combinations described above.

[0032] As shown in the example of Figure 4, the charge / discharge control unit 312 calculates the sum of the input power limit values ​​of the storage batteries 52 of the storage battery units 5 belonging to the generated first storage battery group G1 and the sum of the output power limit values ​​of the storage batteries 52 of the storage battery units 5 belonging to the generated second storage battery group G2.

[0033] Furthermore, the charge / discharge control unit 312 selects a combination of the first storage battery group G1, which will be the charging side, and the second storage battery group G2, which will be the discharging side, from among multiple combinations based on the calculated sum of the input power limit values ​​of the first storage battery group G1 and the calculated sum of the output power limit values ​​of the second storage battery group G2.

[0034] For example, the greater the amount of power that can be discharged from the discharging storage battery 52, the more sufficiently charged the storage battery 52. ​​For this reason, it is preferable that the charge / discharge control unit 312 selects, from among a plurality of combinations, the combination that maximizes the total output power limit value of the discharging second storage battery group G2.

[0035] Furthermore, if there is a large difference between the amount of power that can be discharged from the discharging battery 52 and the amount of power that can be charged to the charging battery 52, sufficient discharging or charging may not be possible. Therefore, the charge / discharge control unit 312 preferably selects, from among multiple combinations, a combination that has the smallest difference between the sum of the input power limit values ​​of the first storage battery group G1 and the sum of the output power limit values ​​of the second storage battery group G2. Furthermore, the charge / discharge control unit 312 may select, from among multiple combinations, a combination in which the sum of the input power limit values ​​of the first storage battery group G1 and the sum of the output power limit values ​​of the second storage battery group G2 are the same.

[0036] In addition, it is preferable that the charge / discharge control unit 312 selects, from among multiple combinations, a combination in which the sum of the output power limit values ​​of the second storage battery group G2, which is the discharging side, is greater than the sum of the input power limit values ​​of the first storage battery group G1, which is the charging side.

[0037] Furthermore, the charge / discharge control unit 312 preferably selects, from among the multiple combinations, a combination in which the difference between the sum of the output power limit values ​​of the second storage battery group G2 and the sum of the input power limit values ​​of the first storage battery group G1 is greater than the amount of power currently being output to the outside from the power storage system 1. The charge / discharge control unit 312 preferably selects, from among the multiple combinations, a combination in which the difference between the sum of the output power limit values ​​of the second storage battery group G2 and the sum of the input power limit values ​​of the first storage battery group G1 is greater than the amount of power currently being input to the power storage system 1 from the outside.

[0038] The charge / discharge control unit 312 selects a combination of a first storage battery group G1 that will be the charging side and a second storage battery group G2 that will be the discharging side from among multiple combinations based on the selection criteria described above. For example, the charge / discharge control unit 312 may select a combination that satisfies all of the selection criteria described above. Alternatively, the charge / discharge control unit 312 may select a combination that satisfies the largest number of selection criteria from among multiple combinations. For example, in the example of FIG. 4 , storage batteries 52A and 52B are selected as the first storage battery group G1 that will be the charging side, and storage batteries 52C and 52D are selected as the second storage battery group G2 that will be the discharging side. FIG. 5 is a diagram illustrating an example of storage batteries that will be the discharging side and storage batteries that will be the charging side based on the selected combination. As shown in Figure 5, in this embodiment, for example, the storage battery 52A of the first storage battery unit 5A and the storage battery 52B of the two storage battery units 5B are selected as the charging side, and the storage battery 52C of the third storage battery unit 5C and the storage battery 52D of the fourth storage battery unit 5D are selected as the discharging side.

[0039] The charge / discharge control unit 312 charges the storage batteries 52 of the storage battery units 5 belonging to the first storage battery group G1 with power discharged from the storage batteries 52 of the storage battery units 5 belonging to the selected second storage battery group G2. To this end, the charge / discharge control unit 312 outputs a discharge command D2h to the DC / DC converter 51 of the selected first storage battery group G1 to discharge power from the storage batteries 52 of the storage battery units 5 belonging to the selected first storage battery group G1. The charge / discharge control unit 312 outputs a power receiving command D2j to the DC / DC converter 51 of the selected second storage battery group G2.

[0040] Here, the charge / discharge control unit 312 may output a command to the DC / DC converter 51 to perform droop control of each storage battery unit 5. The droop control changes the droop slope while fixing the droop intercept of each storage battery unit 5 to an initial value (zero) so as to keep the voltage of the DC bus 4 constant and suppress variations in the state (SOC, etc.) of each storage battery unit 5. In addition, when charging / discharging a desired amount of power to / from a target unit that is at least one storage battery unit 5 among the multiple storage battery units 5, the charge / discharge control unit 312 may perform a process of changing the droop intercept of the target unit as part of the droop control.

[0041] The predetermined program executed by the processor 31 is stored on a computer-readable recording medium. Computer-readable recording media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories. The computer program may be distributed to a computer via a communication line, and the computer that receives the distribution may execute the program. The program may also be a program for implementing some of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the above-described functions in combination with a program already stored in the computer system.

[0042] The memory 32 has a memory area necessary for the operation of the processor 31 .

[0043] The storage 33 is a so-called auxiliary storage device, such as a hard disk drive (HDD), a solid state drive (SSD), etc. The storage 33 stores data that each part of the processor 31 acquires, generates, and references during processing.

[0044] The communication interface 34 is an interface for transmitting and receiving various data and control signals (information D1 about the storage battery, discharge command D2h, power receiving command D2j) between each storage battery unit.

[0045] (Processing flow of control device) Fig. 6 is a flowchart showing an example of processing by a control device according to an embodiment. Here, with reference to Fig. 6, a processing flow in a case where the control device 3 operates some of the storage battery units 5 at a desired charge / discharge power will be described. The control device 3 repeatedly executes the processing flow shown in Fig. 6 at preset time intervals.

[0046] First, the charge / discharge control unit 312 acquires information on preset charge / discharge conditions from each part of the power storage system 1 (step S11) to determine whether or not to perform a charge / discharge operation in which charging / discharging is performed among the storage batteries 52 of the multiple storage battery units 5. The information on charge / discharge conditions acquired here includes, for example, the temperature of each storage battery 52, information indicating the occurrence of a failure in each part, and the like.

[0047] The charge / discharge control unit 312 determines whether or not the predetermined charge / discharge conditions are satisfied based on the information regarding the charge / discharge conditions acquired in step S11 (step S12). If the predetermined charge / discharge conditions are satisfied (step S12: Yes), the charge / discharge control unit 312 proceeds to step S13 and subsequent steps and performs charge / discharge operation. If the charge / discharge conditions are not satisfied (step S12: No), the charge / discharge control unit 312 does not perform charge / discharge operation and terminates the process. Specifically, for example, if the temperature of the storage battery 52 is lower than a predetermined threshold, the charge / discharge control unit 312 determines that the charge / discharge conditions are satisfied. This is because if the temperature of the storage battery 52 is sufficiently high, there is no need to increase the temperature by charging from another storage battery 52. ​​If, for example, some kind of malfunction has occurred in the power storage system 1, the charge / discharge conditions are determined not to be satisfied, and the process terminates.

[0048] Next, the acquisition unit 311 acquires the information D1 about the storage battery from each storage battery unit 5 at predetermined intervals (step S13).

[0049] Next, the charge / discharge control unit 312 determines whether the input power limit value and output power limit value set for each of the storage batteries 52 of the multiple storage battery units 5, which are included in the storage battery-related information D1, satisfy preset limit value conditions (step S14). For example, the charge / discharge control unit 312 determines whether the input power limit value of each storage battery 52 is equal to or less than a preset first threshold. If the input power limit value is greater than the first threshold (step S14: No), the charge / discharge control unit 312 does not perform the charge / discharge operation and terminates the process. If the input power limit value is equal to or less than the first threshold (step S14: Yes), the charge / discharge control unit 312 proceeds to step S15. If the input power limit value is equal to or less than the first threshold, i.e., if the input power limit value is small, this means that the storage battery 52 has a low input capacity. In other words, the temperature of the storage battery 52 is lower than the threshold, and the amount of power that can be input is small. Therefore, the temperature of the storage battery 52 is increased in steps S15 and thereafter. Furthermore, for example, the charge / discharge control unit 312 determines whether the output power limit value of each storage battery 52 is equal to or less than a preset second threshold. As a result, if the output power limit value is greater than the second threshold (step S14: No), the charge / discharge control unit 312 does not perform the charge / discharge operation and ends the process. If the output power limit value is equal to or less than the second threshold (step S14: Yes), the charge / discharge control unit 312 proceeds to step S15. In this case, the temperature of the storage battery 52 is lower than the threshold, and the power that can be output is small. Therefore, from step S15 onwards, the temperature of the storage battery 52 is increased.

[0050] Next, the charge / discharge control unit 312 generates multiple combinations into a first storage battery group G1 including the storage batteries 52 of at least one storage battery unit 5 and a second storage battery group G2 including the storage batteries 52 of the other remaining storage battery units 5 (step S15).

[0051] Next, the charge / discharge control unit 312 calculates the sum of the input power limit values ​​of the storage batteries 52 of the storage battery units 5 belonging to the generated first storage battery group G1 and the sum of the output power limit values ​​of the storage batteries 52 of the storage battery units 5 belonging to the generated second storage battery group G2.

[0052] Furthermore, the charge / discharge control unit 312 selects a combination of the first storage battery group G1 to be the charging side and the second storage battery group G2 to be the discharging side from among multiple combinations based on the calculated sum of the input power limit values ​​of the first storage battery group G1 and the calculated sum of the output power limit values ​​of the second storage battery group G2 (step S16).

[0053] The charge / discharge control unit 312 charges the power discharged from the storage battery 52 of the storage battery unit 5 belonging to the selected second storage battery group G2 into the storage battery 52 of the storage battery unit 5 belonging to the first storage battery group G1 (step S17).

[0054] (Operations and Effects) As described above, the control device 3 for the power storage system 1, the power storage system 1, and the control method for the power storage system 1 according to the present embodiment discharge the storage battery 52 of at least one of the multiple storage battery units 5 and charge the storage battery 52 of the remaining storage battery units 5 based on the input power limit value and the output power limit value set for each of the storage batteries 52 of the multiple storage battery units 5. As a result, the storage battery 52 on the charging side is charged with power supplied from the discharging side, thereby increasing the temperature of the storage battery 52 and improving the efficiency of the storage battery 52. ​​Here, the higher the temperature of the storage battery 52, the higher the efficiency of the storage battery 52, and accordingly, the efficiency of the charge / discharge operation. As a result, the temperature of the storage battery 52 can be efficiently increased by the charge / discharge operation. By repeatedly executing the above-described process at predetermined time intervals, the efficiency of the temperature increase of the storage battery 52 due to the charge / discharge operation increases at an accelerated rate, thereby enabling efficient temperature adjustment in the power storage system 1. Here, the input power limit value and the output power limit value are set based on the terminal voltage, temperature, etc. of the storage batteries 52. Even if the characteristics of the storage batteries 52, such as the degree of deterioration, capacity, and performance, are different, the actual values ​​of the terminal voltage and temperature of each storage battery 52 can be directly acquired. As a result, the input power limit value and the output power limit value reflect the terminal voltage and temperature of each storage battery 52 at that time. Therefore, unlike the SOC, even if the values ​​are the same, the actual output does not vary depending on the characteristics of the storage batteries 52, such as the degree of deterioration, capacity, and performance. As a result, even if the actual amounts of power stored in the storage batteries 52 differ among the multiple storage batteries 52 in the multiple storage battery units 5, the input power limit value and the output power limit value are set based on the actual amounts of power stored in the storage batteries 52. Therefore, the temperature control of the multiple storage batteries 52 constituting the power storage system 1 can be performed efficiently, allowing the target temperature to be reached quickly.

[0055] The control device 3 also divides the batteries 52 of the multiple battery units 5 into a first battery group G1 and a second battery group G2, and selects the batteries 52 of the first battery group G1 to be the charging side and the batteries 52 of the second battery group G2 to be the discharging side based on the sum of the input power limit values ​​of the first battery group G1 and the sum of the output power limit values ​​of the second battery group G2. This allows the temperature of the multiple batteries 52 constituting the power storage system 1 to be efficiently controlled and quickly reach a target temperature.

[0056] Furthermore, the control device 3 selects a combination of the first storage battery group G1 as the charging side and the second storage battery group G2 as the discharging side from among a plurality of combinations based on the amount of power output to or input from the outside, the sum of the input power limit value of the first storage battery group G1, and the sum of the output power limit value of the second storage battery group G2. This allows the temperature of the plurality of storage batteries 52 constituting the power storage system 1 to be efficiently controlled and quickly reach a target temperature while ensuring the amount of power output to or input from the outside.

[0057] As described above, the embodiments according to the present disclosure have been described. However, the above-described embodiments are presented as examples and are not intended to limit the scope of the disclosure. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the disclosure. These embodiments and their modifications are included in the scope and spirit of the disclosure, as well as in the disclosure described in the claims and their equivalents.

[0058] <Additional Notes> The control device 3 of the power storage system 1, the power storage system 1, the control method for the power storage system 1, and the program described in the embodiment can be understood, for example, as follows.

[0059] (1) The control device 3 of the energy storage system 1 according to the first aspect is a control device 3 of the energy storage system 1 in which a plurality of storage battery units 5, each having a storage battery 52 and a DC / DC converter 51 that converts the voltage of charging and discharging power to and from the storage battery 52, are connected in parallel via a DC bus 4, and the control device 3 includes: an acquisition unit 311 that acquires limit value information regarding the input power limit value and output power limit value set for each of the storage batteries 52 of the plurality of storage battery units 5; and a charge / discharge control unit 312 that charges the storage battery 52 of the remaining storage battery units 5 of the plurality of storage battery units 5 with power discharged from the storage battery 52 of at least one of the plurality of storage battery units 5 based on the input power limit value and output power limit value set for each of the storage batteries 52.

[0060] The control device 3 of this power storage system 1 discharges the storage battery 52 of at least one of the storage battery units 5 and charges the storage battery 52 of the remaining storage battery units 5 based on the input power limit value and the output power limit value set for each of the storage batteries 52 of the storage battery units 5. As a result, the storage battery 52 on the charging side is charged with power supplied from the discharging side, causing the temperature of the storage battery 52 to increase and the output limit value of the storage battery 52 to be relaxed. Here, the input power limit value and the output power limit value are set based on the terminal voltage, temperature, etc. of the storage battery 52. ​​Therefore, even if the storage batteries 52 have different degrees of deterioration, the actual values ​​of the terminal voltage and temperature of each storage battery 52 can be directly acquired. As a result, the input power limit value and the output power limit value reflect the terminal voltage and temperature of each storage battery 52 at that time. Therefore, unlike the SOC, even if the values ​​are the same, the actual output does not vary depending on the degree of deterioration, etc. of the storage batteries 52. As a result, even if the actual amounts of electricity stored in the storage batteries 52 differ among the multiple storage batteries 52 in the multiple storage battery units 5, the input power limit value and the output power limit value are set based on the actual amounts of electricity stored in the storage batteries 52. Therefore, the temperature of the multiple storage batteries 52 constituting the electricity storage system 1 can be efficiently controlled, and the target temperature can be reached quickly.

[0061] (2) A control device 3 of a power storage system 1 according to a second aspect is the control device 3 of the power storage system 1 of (1), in which the charge / discharge control unit 312 generates a plurality of combinations in which the storage batteries 52 of the plurality of storage battery units 5 are divided into a first storage battery group G1 and a second storage battery group G2, and calculates a sum of input power limit values ​​of the storage batteries 52 of the storage battery units 5 belonging to the first storage battery group G1 and a sum of output power limit values ​​of the storage batteries 52 of the storage battery units 5 belonging to the second storage battery group G2. Based on the calculated sum of the input power limit values ​​of the first storage battery group G1 and the calculated sum of the output power limit values ​​of the second storage battery group G2, a combination of the first storage battery group G1 to be the charging side and the second storage battery group G2 to be the discharging side is selected from the multiple combinations, and the power discharged from the storage battery 52 of the storage battery unit 5 belonging to the selected second storage battery group G2 is charged into the storage battery 52 of the storage battery unit 5 belonging to the first storage battery group G1.

[0062] As a result, the storage batteries 52 of the plurality of storage battery units 5 are divided into a first storage battery group G1 and a second storage battery group G2, and the storage batteries 52 of the first storage battery group G1 to be charged and the storage batteries 52 of the second storage battery group G2 to be discharged are selected based on the sum of the input power limit values ​​of the first storage battery group G1 and the sum of the output power limit values ​​of the second storage battery group G2. As a result, the temperature of the plurality of storage batteries 52 constituting the power storage system 1 can be efficiently controlled, and the target temperature can be reached quickly.

[0063] (3) The control device 3 of the energy storage system 1 according to the third aspect is the control device 3 of the energy storage system 1 of (1) or (2), in which the acquisition unit 311 acquires the amount of power output to or input from the outside in each of the storage batteries 52 of the plurality of storage battery units 5, and the charge / discharge control unit 312 selects, from the plurality of combinations, a combination of the first storage battery group G1 to be the charging side and the second storage battery group G2 to be the discharging side based on the amount of power, the sum of the input power limit value of the first storage battery group G1, and the sum of the output power limit value of the second storage battery group G2.

[0064] With this configuration, the amount of power output to or input from the outside is excluded, and a combination of the first storage battery group G1 to be the charging side and the second storage battery group G2 to be the discharging side is selected from the plurality of combinations based on the sum of the input power limit values ​​of the first storage battery group G1 and the sum of the output power limit values ​​of the second storage battery group G2. This ensures the amount of power exchanged between the storage batteries 52 and the outside, while efficiently controlling the temperatures of the plurality of storage batteries 52 constituting the power storage system 1 and enabling them to quickly reach a target temperature.

[0065] (4) The fourth aspect of the energy storage system 1 includes a plurality of energy storage units 5 each having a storage battery 52 and a DC / DC converter 51 that converts the voltage of the charging / discharging power for the storage battery 52, and a control device 3 for any one of the energy storage systems 1 (1) to (3).

[0066] This allows the temperature of the plurality of storage batteries 52 constituting the power storage system 1 to be controlled efficiently and quickly reach the target temperature.

[0067] (5) A fifth aspect of the control method for a power storage system 1 is a control method for a power storage system 1 in which a plurality of storage battery units 5, each having a storage battery 52 and a DC / DC converter 51 that converts the voltage of charging and discharging power to and from the storage battery 52, are connected in parallel via a DC bus 4, and includes a step S13 of acquiring limit value information regarding an input power limit value and an output power limit value set for each of the storage batteries 52 of the plurality of storage battery units 5, and a step S17 of charging the storage battery 52 of the remaining storage battery units 5 of the plurality of storage battery units 5 with power discharged from the storage battery 52 of at least one of the plurality of storage battery units 5 based on the input power limit value and output power limit value set for each of the storage batteries 52.

[0068] This makes it possible to provide a control method that can efficiently control the temperatures of the multiple storage batteries 52 that make up the power storage system 1 and quickly reach a target temperature.

[0069] (6) A program relating to the sixth aspect causes a control device 3 of a power storage system 1 in which a plurality of storage battery units 5, each having a storage battery 52 and a DC / DC converter 51 that converts the voltage of charging and discharging power to and from the storage battery 52, are connected in parallel via a DC bus 4 to execute the following steps: Step S13 acquires limit value information regarding the input power limit value and output power limit value set for each of the storage batteries 52 of the plurality of storage battery units 5; and Step S17 charges the storage battery 52 of the remaining storage battery units 5 of the plurality of storage battery units 5 with power discharged from the storage battery 52 of at least one of the plurality of storage battery units 5 based on the input power limit value and output power limit value set for each of the storage batteries 52.

[0070] This makes it possible to provide a control device 3 that can efficiently control the temperatures of the multiple storage batteries 52 that make up the power storage system 1 and quickly reach a target temperature.

[0071] According to the above-described aspect, the temperature control of the plurality of storage batteries is performed efficiently, and the target temperature is reached quickly.

[0072] REFERENCE SIGNS LIST 1... Power storage system 3... Control device 5, 5A to 5D... Storage battery unit 51... DC / DC converter 52, 52A to 52D... Storage battery 311... Acquisition unit 312... Charge / discharge control unit G1... First storage battery group G2... Second storage battery group

Claims

1. A control device for an energy storage system in which multiple storage battery units, each having a storage battery and a DC / DC converter that converts the voltage of the charging / discharging power to the storage battery, are connected in parallel, comprising: an acquisition unit that acquires limit value information regarding an input power limit value and an output power limit value set for each of the storage batteries of the multiple storage battery units; and a charge / discharge control unit that charges the storage battery of the remaining storage battery units of the multiple storage battery units with power discharged from the storage battery of at least one of the multiple storage battery units based on the input power limit value and output power limit value set for each of the storage batteries.

2. The control device for a power storage system as described in claim 1, wherein the charge / discharge control unit: generates a plurality of combinations by dividing the storage batteries of the plurality of storage battery units into a first storage battery group and a second storage battery group; calculates a sum of the input power limit values ​​of the storage batteries of the storage battery units belonging to the first storage battery group and a sum of the output power limit values ​​of the storage batteries of the storage battery units belonging to the second storage battery group; selects from the plurality of combinations a combination of the first storage battery group to be the charging side and the second storage battery group to be the discharging side based on the calculated sum of the input power limit value of the first storage battery group and the calculated sum of the output power limit value of the second storage battery group; and charges the storage battery of the storage battery unit belonging to the first storage battery group with power discharged from the storage battery of the storage battery unit belonging to the selected second storage battery group.

3. The control device for a power storage system as described in claim 2, wherein the acquisition unit acquires the amount of power output to the outside or input from the outside for each of the storage batteries of the multiple storage battery units, and the charge / discharge control unit selects a combination of the first storage battery group to be the charging side and the second storage battery group to be the discharging side from among the multiple combinations based on the amount of power, the sum of the input power limit value of the first storage battery group, and the sum of the output power limit value of the second storage battery group.

4. A power storage system comprising: a plurality of storage battery units each having a storage battery and a DC / DC converter that converts the voltage of charging / discharging power for the storage battery; and a power storage system control device according to any one of claims 1 to 3.

5. A control method for a power storage system in which multiple storage battery units, each having a storage battery and a DC / DC converter that converts the voltage of charging / discharging power to the storage battery, are connected in parallel, comprising the steps of: acquiring limit value information regarding an input power limit value and an output power limit value set for each of the storage batteries of the multiple storage battery units; and charging the storage battery of the remaining storage battery units among the multiple storage battery units with power discharged from the storage battery of at least one of the multiple storage battery units based on the input power limit value and output power limit value set for each of the storage batteries.

6. A program that causes a control device of an energy storage system in which multiple storage battery units, each having a storage battery and a DC / DC converter that converts the voltage of charging and discharging power to the storage battery, are connected in parallel to execute the steps of: acquiring limit value information regarding the input power limit value and output power limit value set for each of the storage batteries of the multiple storage battery units; and charging the storage battery of the remaining storage battery units among the multiple storage battery units with power discharged from the storage battery of at least one of the multiple storage battery units based on the input power limit value and output power limit value set for each of the storage batteries.

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