Power system and control method

Abstract

To provide an electric power system and a control method capable of allowing operation of a power storage device to have flexibility.SOLUTION: A power control system comprises: a power storage device installed in a facility; and a controller for controlling the power storage device. The controller performs a first control that uses a first depth of discharge as a depth of discharge of the power storage device when a first condition related to deterioration of the power storage device is not satisfied, and performs a second control that uses a second depth of discharge larger than the first depth of discharge as a depth of discharge of the power storage device when the first condition related to deterioration of the power storage device is satisfied.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a power system and a control method. [Background technology]

[0002] In recent years, technologies that use power storage devices as distributed power sources (e.g., Virtual Power Plants (VPPs)) have become known in order to maintain the balance between power supply and demand in a power grid (e.g., Patent Documents 1 and 2). It is conceivable to use power storage devices as power sources for VPPs and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 041010 Brochure [Patent Document 2] International Publication No. 2016 / 084396 Brochure Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the use of a system capacity utilization rate (%) as an index representing the performance of a power storage device is being considered. The system capacity utilization rate (%) may be expressed by effective capacity (kWh) / total capacity (kWh). The effective capacity (kWh) may be expressed by total capacity (kWh) x depth of discharge (%) x system discharge efficiency (%). The depth of discharge may be referred to as DOD. The DOD is a value that affects the capacity degradation of the power storage device, and can be set by the manufacturer of the power storage device, etc.

[0005] In this context, if we consider a case in which energy storage devices are used to maintain the balance between power supply and demand in a power grid, if the DOD is fixed at a single value, it may not be possible to properly maintain the balance between power supply and demand in the power grid.

[0006] Therefore, the present invention has been made to solve the above-mentioned problems, and has an object to provide a power system and a control method that enable flexibility in the operation of a power storage device. [Means for solving the problem]

[0007] One embodiment of the disclosure is a power system that includes a power storage device installed in a facility and a control unit that controls the power storage device, wherein the control unit performs a first control that uses a first depth of discharge as the depth of discharge of the power storage device when a first condition related to deterioration of the power storage device is not satisfied, and performs a second control that uses a second depth of discharge greater than the first depth of discharge as the depth of discharge of the power storage device when the first condition related to deterioration of the power storage device is satisfied.

[0008] One aspect of the disclosure is a control method comprising a step A of controlling an energy storage device installed in a facility, the step A including a step of performing a first control using a first depth of discharge as the depth of discharge of the energy storage device when a first condition related to deterioration of the energy storage device is not satisfied, and a step of performing a second control using a second depth of discharge greater than the first depth of discharge as the depth of discharge of the energy storage device when the first condition related to deterioration of the energy storage device is satisfied. Effect of the Invention

[0009] According to the present invention, it is possible to provide a power system and a control method that enable flexibility in the operation of a power storage device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a power management system 1 according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a facility 100 according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing a power storage device 120 according to an embodiment. [Figure 4]FIG. 4 is a diagram showing the EMS 160 according to the embodiment. [Diagram 5] FIG. 5 is a diagram for explaining a system capacity utilization rate according to the embodiment. [Figure 6] FIG. 6 is a diagram for explaining a system capacity utilization rate according to the embodiment. [Figure 7] FIG. 7 is a diagram for explaining the first control and the second control according to the embodiment. [Figure 8] FIG. 8 is a diagram for explaining the first control and the second control according to the embodiment. [Figure 9] FIG. 9 is a diagram for explaining the first control and the second control according to the embodiment. [Figure 10] FIG. 10 is a diagram for explaining the first control and the second control according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic.

[0012] [Embodiment] (Power Management System) A power management system according to an embodiment will be described below. The power management system may be simply referred to as a power system.

[0013] 1, the power management system 1 includes a facility 100. The power management system 1 may include a power management server 200.

[0014] Here, the facility 100 and the power management server 200 are configured to be able to communicate with each other via a network 11. The network 11 may include the Internet, a dedicated line such as a Virtual Private Network (VPN), or a mobile communication network.

[0015] The facility 100 is connected to the power system 12, and may receive power from the power system 12, or may supply power to the power system 12. Power from the power system 12 to the facility 100 may be referred to as forward flow power, purchased power, or demanded power. Power from the facility 100 to the power system 12 may be referred to as reverse flow power or sold power. In FIG. 1, facilities 100A to 100C are illustrated as examples of the facility 100.

[0016] Although not particularly limited, the facility 100 may be a facility such as a residence, a facility such as a store, or a facility such as an office. The facility 100 may be an apartment building including two or more residences. The facility 100 may be a complex including at least two or more of the following facilities: a residence, a store, and an office. Details of the facility 100 will be described later (see FIG. 2).

[0017] The power management server 200 is managed by a business operator who manages power related to the power system 12. The business operator may be a power generation business operator, a power transmission and distribution business operator, or a retail electricity business operator. The business operator may be a resource aggregator (hereinafter, RA), or an aggregation coordinator (AC) that manages the RA. The RA may be a business operator who adjusts the power supply and demand balance of the power system 12. The adjustment of the power supply and demand balance may include a transaction (hereinafter, negawatt trading) in which reduced power of the demand power (flow power) of the facility 100 is exchanged for value. The adjustment of the power supply and demand balance may include a transaction in which increased power of reverse flow power is exchanged for value. In the VPP, the RA may be a business operator such as a power generation business operator, a power transmission and distribution business operator, or a retail electricity business operator.

[0018] In the embodiment, communication between the power management server 200 and the EMS 160 is performed according to a first protocol. On the other hand, communication between the EMS 160 and the distributed power source (the solar cell device 110, the power storage device 120, or the fuel cell device 130) is performed according to a second protocol different from the first protocol. For example, the first protocol may be a protocol conforming to Open ADR (Automated Demand Response) or a unique dedicated protocol. For example, the second protocol may be a protocol conforming to ECHONET Lite (registered trademark), SEP (Smart Energy Profile) 2.0, KNX, or a unique dedicated protocol. Note that the first protocol and the second protocol may be different from each other, and may be, for example, both of which may be unique dedicated protocols, provided that they are protocols created according to different rules. However, the first protocol and the second protocol may be protocols created according to the same rules.

[0019] (facility) A facility according to an embodiment will be described below. As shown in Fig. 2, the facility 100 includes a solar cell device 110, a power storage device 120, a fuel cell device 130, a load device 140, and an EMS (Energy Management System) 160. The facility 100 may also include a measuring device 190.

[0020] The solar cell device 110 is a distributed power source that generates power in response to light such as sunlight. For example, the solar cell device 110 is configured with a PCS (Power Conditioning System) and a solar panel. Here, installation may mean that the solar cell device 110 and the power grid 12 are connected.

[0021] The power storage device 120 is a distributed power source that charges and discharges power. For example, the power storage device 120 is configured with a PCS and a power storage cell. Here, the term "installed" may mean that the power storage device 120 and the power grid 12 are connected to each other.

[0022] The fuel cell device 130 is a distributed power source that generates power using fuel. For example, the fuel cell device 130 is composed of a PCS and a fuel cell. Here, "installation" may mean that the fuel cell device 130 and the power system 12 are connected.

[0023] For example, the fuel cell device 130 may be a solid oxide fuel cell (SOFC; Solid Oxide Fuel Cell), a polymer electrolyte fuel cell (PEFC; Polymer Electrolyte Fuel Cell), a phosphoric acid fuel cell (PAFC; Phosphoric Acid Fuel Cell), or a molten carbonate fuel cell (MCFC; Molten Carbonate Fuel Cell).

[0024] The load devices 140 are devices that consume power, such as the power grid 12, the solar cell device 110, the power storage device 120, and the fuel cell device 130. For example, the load devices 140 may include an air conditioner that adjusts the temperature of a predetermined space in the facility 100, or may include a lighting device that adjusts the illuminance of a predetermined space in the facility 100. The load devices 140 may include video equipment, audio equipment, a refrigerator, a washing machine, a personal computer, and the like.

[0025] The EMS 160 manages the power related to the facility 100. The EMS 160 may control the solar cell device 110, the power storage device 120, the fuel cell device 130, and the load devices 140. In the embodiment, the EMS 160 is illustrated as an apparatus that receives a control command from the power management server 200, but such an apparatus may be referred to as a Gateway or simply as a control unit. The EMS 160 may be referred to as a Local EMS (LEMS) or a Home EMS (HEMS) to distinguish it from the power management server 200. Details of the EMS 160 will be described later (see FIG. 4).

[0026] The measuring device 190 measures forward flow power from the power system 12 to the facility 100. The measuring device 190 may measure reverse flow power from the facility 100 to the power system 12. For example, the measuring device 190 may be a smart meter belonging to a power company. The measuring device 190 may transmit an information element indicating a measurement result (an integrated value of forward flow power or reverse flow power) in a first interval (e.g., 30 minutes) to the EMS 160 at the first interval. The measuring device 190 may transmit an information element indicating a measurement result in a second interval (e.g., 1 minute) shorter than the first interval to the EMS 160.

[0027] (Electricity storage device) The power storage device according to the embodiment will be described below. As shown in Fig. 3, the power storage device 120 includes a BT 121 and a control unit 122. Although omitted in Fig. 3, the power storage device 120 may include a PCS.

[0028] The BT 121 is a power storage cell included in the power storage device 120. The control unit 122 controls the BT 121. In the embodiment, the control unit 122 may be an example of a control unit that controls the power storage device 120.

[0029] Although not particularly limited, the control unit 122 may control the BT 121 based on a command received from the EMS 160, or may control the BT 121 based on a command received from the power management server 200. In such a case, the power storage device 120 may have a communication unit configured by a communication module.

[0030] For example, the control unit 122 may include at least one processor. The at least one processor may be configured by a single integrated circuit (IC), or may be configured by a plurality of circuits (such as integrated circuits and / or discrete circuits) communicatively connected to each other.

[0031] In the embodiment, when a first condition related to the deterioration of the power storage device 120 is not satisfied, the control unit 122 executes a first control using a first depth of discharge (hereinafter, first DOD) as the depth of discharge of the power storage device 120. When the first condition related to the deterioration of the power storage device 120 is satisfied, the control unit 122 executes a second control using a second depth of discharge (hereinafter, second DOD) larger than the first DOD as the depth of discharge of the power storage device 120. The first control and the second control will be described in detail later.

[0032] The depth of discharge is a term that means the ratio of the amount of discharge to the capacity of the power storage device 120 (see, for example, FIG. 5). The depth of discharge may be a value that can be set by the manufacturer of the power storage device 120 or the like.

[0033] (EMS) The EMS according to the embodiment will be described below. As shown in FIG.

[0034] The first communication unit 161 is configured by a communication module. The communication module may be a wireless communication module conforming to a standard such as IEEE802.11a / b / g / n / ac / ax, ZigBee, Wi-SUN, LTE, 5G, or 6G, or may be a wired communication module conforming to a standard such as IEEE802.3.

[0035] For example, the first communication unit 161 communicates with the power management server 200 via the network 11. As described above, the first communication unit 161 communicates according to the first protocol. For example, the first communication unit 161 receives a first message from the power management server 200 according to the first protocol. The first communication unit 161 transmits a first message response to the power management server 200 according to the first protocol.

[0036] The second communication unit 162 is configured by a communication module. The communication module may be a wireless communication module conforming to a standard such as IEEE802.11a / b / g / n / ac / ax, ZigBee, Wi-SUN, LTE, 5G, or 6G, or may be a wired communication module conforming to a standard such as IEEE802.3.

[0037] For example, the second communication unit 162 communicates with devices included in the facility 100 (the solar cell device 110, the power storage device 120, and the fuel cell device 130). As described above, the second communication unit 162 communicates according to the second protocol. For example, the second communication unit 162 transmits a second message to the distributed power source according to the second protocol. The second communication unit 162 receives a second message response from the distributed power source according to the second protocol.

[0038] The control unit 163 may include at least one processor. The at least one processor may be configured by a single integrated circuit (IC), or may be configured by a plurality of circuits (such as integrated circuits and / or discrete circuits) communicatively connected.

[0039] For example, the control unit 163 may control the distributed power sources (the solar cell device 110, the power storage device 120, and the fuel cell device 130) provided in the facility 100 based on a control command received from the power management server 200.

[0040] (System capacity utilization rate) The system capacity utilization rate according to the embodiment will be described below. The system capacity utilization rate (%) may be expressed by effective capacity (kWh) / total capacity (kWh). The effective capacity (kWh) may be expressed by total capacity (kWh) x depth of discharge (%) x system discharge efficiency (%). The effective capacity (kWh) used in calculating the system capacity utilization rate (%) may be an initial value of the effective capacity (kWh).

[0041] As shown in FIG. 5, the total capacity (kWh) of the power storage device 120 isLOWER The following capacity (in FIG. 5, the unusable region (discharging)) may be included. The unusable region (discharging) is a region in which discharging of the power storage device 120 is restricted. The unusable region (discharging) is a region that may affect deterioration of the power storage device 120, and may be determined by the characteristics of the power storage device 120.

[0042] When emergency capacity (BCP (Business Continuity Plan) capacity) is defined to respond to emergencies such as disasters, the BCP capacity is set at a lower threshold T LOWER A threshold T greater than BCP and the lower threshold T LOWER In other words, the unusable region (discharging) is a region different from the BCP capacity.

[0043] On the other hand, the total capacity (kWh) of the power storage device 120 is limited to the upper threshold T UPPER The above capacity (unusable area (charging) in FIG. 5) may be included. The unusable area (charging) is an area in which charging of the power storage device 120 is restricted. The unusable area (charging) is an area that may affect the deterioration of the power storage device 120, and may be determined by the characteristics of the power storage device 120. The unusable area (charging) may be considered as a loss portion due to the system discharge efficiency (%).

[0044] Under such a premise, the discharge depth (%) may be expressed by (total capacity (kWh)-unusable area (discharge)) / total capacity (kWh). For example, if the total capacity (kWh) is 10 kWh and the unusable area (discharge) is 0.5 kWh, the capacity based on the discharge depth is 9.5 kWh, and the discharge depth (%) is 95%. If the system discharge efficiency (%) is 90%, the effective capacity is 8.55 kWh, and the system capacity utilization rate (%) is 85.5%. Similarly, if the total capacity (kWh) is 10 kWh and the unusable area (discharge) is 1.5 kWh, the capacity based on the discharge depth is 8.5 kWh, and the discharge depth (%) is 85%. If the system discharge efficiency (%) is 90%, the effective capacity is 7.65 kWh, and the system capacity utilization rate (%) is 76.5%.

[0045] Although not particularly limited, the system discharge efficiency (%) may be considered as a concept included in the depth of discharge (%). For example, the depth of discharge (%) may be expressed by effective capacity (kWh) / total capacity (kWh). Note that the effective capacity (kWh) is calculated based on the lower limit threshold T LOWER and the upper threshold T UPPER In other words, the depth of discharge (%) may be synonymous with the system capacity utilization rate (%).

[0046] Here, the effective capacity (kWh) may be variable depending on the temperature of the power storage device 120. The temperature of the power storage device 120 may be the surface temperature of the BT 121 (power storage cell) or the internal temperature of the housing of the power storage device 120.

[0047] For example, when the total capacity (kWh) is 10.0 kWh, the effective capacity (kWh) may be displayed in the manner shown in the upper part of Fig. 6. For example, when the temperature of the power storage device 120 is 25°C, the effective capacity (kWh) may be 8.55 kWh, when the temperature of the power storage device 120 is -10°C, the effective capacity (kWh) may be 8.50 kWh, and when the temperature of the power storage device 120 is 40°C, the effective capacity (kWh) may be 8.33 kWh.

[0048] In such a case, the system capacity utilization rate (%) may be displayed in the manner shown in the lower part of Fig. 6. For example, when the temperature of the power storage device 120 is 25°C, the system capacity utilization rate (%) may be 85.5%, when the temperature of the power storage device 120 is -10°C, the system capacity utilization rate (%) may be 85.0%, and when the temperature of the power storage device 120 is 40°C, the system capacity utilization rate (%) may be 83.3%.

[0049] (First control and second control) The first control and the second control according to the embodiment will be described below. As described above, the first control is a control that uses the first DOD as the depth of discharge of the power storage device 120. The second control is a control that uses the second DOD as the depth of discharge of the power storage device 120. In the following, for the sake of simplicity, a case will be described in which the system discharge efficiency (%) is included in the depth of discharge (%). In other words, a case will be described in which the depth of discharge (%) is synonymous with the system capacity utilization rate (%).

[0050] First, a case where the power storage device 120 is charged will be described with reference to FIG. 7. In the first control, the effective capacity (kWh) is calculated based on the lower limit threshold T LOWER and the threshold T1. The threshold T1 is the upper threshold T UPPER The first DOD may be considered as a lower threshold T LOWER and the threshold T1 / total capacity. In contrast, in the second control, the effective capacity (kWh) is expressed as LOWER and a threshold T2. The threshold T2 is a value greater than the threshold T1. The second DOD is a capacity between the lower threshold T LOWER and the threshold T2 / total capacity. In other words, in the second control, at least a part of the unusable area (charging) is released, and the unusable area (charging) may be considered to be used as the effective capacity. That is, by changing the threshold T1 to the threshold T2, the first DOD is changed to the second DOD that is larger than the first DOD.

[0051] Secondly, a case where the power storage device 120 is discharged will be described with reference to Fig. 8. In the first control, the effective capacity (kWh) is calculated by dividing the effective capacity (kWh) by the threshold T1 and the upper threshold T UPPER The threshold T1 is the capacitance between the lower limit threshold T LOWER The first DOD can be considered as having a threshold T1 and an upper threshold T UPPER On the other hand, in the second control, the effective capacity (kWh) is expressed by the capacity between the threshold T2 and the upper threshold T UPPERThe second DOD is a capacity between the threshold T2 and the upper threshold T UPPER and the total capacity. In other words, in the second control, at least a part of the unusable area (discharging) is released, and the unusable area (discharging) may be considered to be used as an effective capacity. That is, by changing the threshold T1 to the threshold T2, the first DOD is changed to the second DOD that is larger than the first DOD.

[0052] Under such a premise, the control unit 122 of the power storage device 120 executes a first control using a first DOD when a first condition related to deterioration of the power storage device 120 is not satisfied. The control unit 122 executes a second control using a second DOD when the first condition related to deterioration of the power storage device 120 is satisfied.

[0053] The first condition may be any condition related to deterioration of the power storage device 120. For example, the first condition may be defined based on at least one selected from a first parameter related to deterioration of the power storage device 120 and a second parameter related to use of the power storage device 120.

[0054] The first parameter may be one or more parameters selected from the temperature of the power storage device 120, a capacity deterioration rate of the power storage device 120, a SOH (State of Health) of the power storage device 120, and an effective capacity of the power storage device 120. The temperature of the power storage device 120 may be a surface temperature of the BT 121 (power storage cell), or may be an internal temperature of a housing of the power storage device 120. The capacity deterioration rate may be expressed as current SOH / initial SOH, or current effective capacity / initial effective capacity, assuming that the initial SOH is 100%.

[0055] In option 1-1, the first condition may be that the temperature of the power storage device 120 is less than a threshold value. The control unit 122 may execute the first control when the temperature of the power storage device 120 is equal to or greater than the threshold value, and execute the second control when the temperature of the power storage device 120 is less than the threshold value. The first condition may be that the temperature of the power storage device 120 from start-up to stop of the power storage device 120 satisfies a predetermined temperature condition. The control unit 122 may execute the first control when the temperature of the power storage device 120 satisfies the predetermined temperature condition, and execute the second control when the temperature of the power storage device 120 does not satisfy the predetermined temperature condition. Although not particularly limited, the predetermined temperature condition may be a condition that determines a range of the temperature of the power storage device 120 from start-up to stop of the power storage device 120 (for example, −10° C. to 40° C.).

[0056] In option 1-2, the first condition may be that the capacity deterioration rate of the power storage device 120 is less than a threshold value. The control unit 122 may execute the first control when the capacity deterioration rate of the power storage device 120 is equal to or greater than the threshold value, and execute the second control when the capacity deterioration rate of the power storage device 120 is less than the threshold value.

[0057] In options 1-3, the first condition may be that the SOH of the power storage device 120 is equal to or greater than a threshold. The control unit 122 may execute the first control when the SOH of the power storage device 120 is less than the threshold, and execute the second control when the SOH of the power storage device 120 is equal to or greater than the threshold.

[0058] In options 1-4, the first condition may be that the effective capacity of the power storage device 120 is equal to or greater than a threshold. The control unit 122 may execute the first control when the effective capacity of the power storage device 120 is less than the threshold, and execute the second control when the effective capacity of the power storage device 120 is equal to or greater than the threshold.

[0059] Two or more options selected from the above-mentioned options 1-1 to 1-4 may be combined.

[0060] The second parameter may be one or more parameters selected from an accumulated usage time of the power storage device 120, a number of charge / discharge cycles of the power storage device 120, an accumulated discharge power of the power storage device 120, and an accumulated charge power of the power storage device 120. The accumulated usage time of the power storage device 120 may be the sum of a discharge time and a charge time, or may be the sum of a discharge time, a charge time, and a standby time.

[0061] In option 2-1, the first condition may be that the accumulated usage time of the power storage device 120 is less than a threshold. The control unit 122 may execute the first control when the accumulated usage time of the power storage device 120 is equal to or greater than the threshold, and may execute the second control when the accumulated usage time of the power storage device 120 is less than the threshold.

[0062] In option 2-2, the first condition may be that the number of charge / discharge cycles of the power storage device 120 is less than a threshold. The control unit 122 may execute the first control when the number of charge / discharge cycles of the power storage device 120 is equal to or greater than the threshold, and may execute the second control when the number of charge / discharge cycles of the power storage device 120 is less than the threshold.

[0063] In option 2-3, the first condition may be that the integrated discharge power of the power storage device 120 is less than a threshold. The control unit 122 may execute the first control when the integrated discharge power of the power storage device 120 is equal to or greater than the threshold, and may execute the second control when the integrated discharge power of the power storage device 120 is less than the threshold.

[0064] In option 2-4, the first condition may be that the integrated charging power of the power storage device 120 is less than a threshold. The control unit 122 may execute the first control when the integrated charging power of the power storage device 120 is equal to or greater than the threshold, and execute the second control when the integrated charging power of the power storage device 120 is less than the threshold.

[0065] Two or more options selected from the above-mentioned options 2-1 to 2-4 may be combined.

[0066] Furthermore, the first condition may be defined by both the first parameter and the second parameter. In the following, the capacity loss rate is exemplified as the first parameter, and the number of charge / discharge cycles is exemplified as the second parameter. However, the capacity loss rate may be replaced with another first parameter, and the number of charge / discharge cycles may be replaced with another second parameter.

[0067] As shown in FIG. 9, the relationship between the capacity deterioration rate and the number of charge / discharge cycles can be expressed by a deterioration curve. The ideal deterioration curve is a deterioration curve assuming a case where only the first control is executed. The allowable deterioration curve is a deterioration curve that is allowable in a case where the first control and the second control are mixed. For example, when the life of the power storage device 120 is defined by the maximum capacity deterioration rate (maximum capacity loss=50% in FIG. 9), the number of charge / discharge cycles at the timing when the ideal deterioration curve reaches the maximum capacity deterioration rate (A in FIG. 9) may be 7,000, and the number of charge / discharge cycles at the timing when the allowable deterioration curve reaches the maximum capacity deterioration rate (B in FIG. 9) may be 6,700. The deviation between the ideal deterioration curve and the allowable deterioration curve may become larger as the number of charge / discharge cycles increases.

[0068] Under such a premise, the first control and the second control will be described by taking the portion X shown in Fig. 9 as an example. Fig. 10 shows an enlarged view of the portion X shown in Fig. 9. Note that, from the viewpoint of simplifying the description, a case in which the ideal deterioration curve and the allowable deterioration curve are approximately parallel to each other in the portion X will be illustrated as an example.

[0069] As shown in FIG. 10, the slope of the deterioration curve associated with the first control is equivalent to the slope of the ideal deterioration curve (here, the ideal deterioration curve and the allowable deterioration curve). On the other hand, the slope of the deterioration curve associated with the second control is larger than the slope of the ideal deterioration curve (here, the ideal deterioration curve and the allowable deterioration curve). The first control and the second control are executed so that the deterioration curve of the power storage device 120 changes between the ideal deterioration curve and the allowable deterioration curve. Therefore, for example, as shown in FIG. 10, in a case where the deterioration curve of the power storage device 120 reaches the allowable deterioration curve at C, the second control is not executed from C onwards, and the first control is executed.

[0070] As a method for realizing such control, the following two options are considered. In either option, the capacity deterioration rate may be calculated for each specific cycle. Although not particularly limited, the specific cycle may be 1 cycle, 10 cycles, or 100 cycles.

[0071] In option 3-1, a target capacity degradation rate to be satisfied when the number of charge / discharge cycles reaches a predetermined number of cycles may be set. The target capacity degradation rate may be defined by the above-mentioned allowable degradation curve. When the number of charge / discharge cycles reaches a predetermined number of cycles, the control unit 122 determines whether or not the first condition is satisfied based on a comparison result between the actual capacity degradation rate and the target capacity degradation rate. Specifically, if the actual capacity degradation rate is smaller than the target capacity degradation rate, the control unit 122 determines that the first condition is satisfied. On the other hand, if the actual capacity degradation rate is larger than the target capacity degradation rate, the control unit 122 determines that the first condition is not satisfied. If the actual capacity degradation rate is equal to the target capacity degradation rate, the control unit 122 may execute the first control or may execute the second control. Note that the predetermined number of cycles may be set to a predetermined number of cycles equal to or greater than two (for example, 1,000, 3,000, 5,000, etc.).

[0072] That is, in option 3-1, it is sufficient to intermittently determine whether the first condition is satisfied. In other words, before the number of charge / discharge cycles reaches a predetermined number of cycles, the determination of whether the first condition is satisfied may be omitted. Therefore, it is possible to reduce the processing load associated with the determination of whether the first condition is satisfied.

[0073] As described above, the capacity deterioration rate may be replaced with another first parameter, and the number of charge / discharge cycles may be replaced with another second parameter. That is, option 3-1 may be expressed as shown below. A target for the first parameter to be satisfied when the second parameter reaches a predetermined parameter is determined. When the second parameter reaches the predetermined parameter, the control unit 122 determines whether the first condition is satisfied based on a comparison result between the actual performance of the first parameter and the target for the first parameter.

[0074] In option 3-2, a target number of charge / discharge cycles to be satisfied when the capacity deterioration rate reaches a predetermined deterioration rate may be set. The target number of charge / discharge cycles may be defined by the above-mentioned allowable deterioration curve. When the capacity deterioration rate reaches the predetermined deterioration rate, the control unit 122 determines whether or not the first condition is satisfied based on a comparison result between the actual number of charge / discharge cycles and the target number of charge / discharge cycles. Specifically, if the actual number of charge / discharge cycles is greater than the target number of charge / discharge cycles, the control unit 122 determines that the first condition is satisfied. On the other hand, if the actual number of charge / discharge cycles is less than the target number of charge / discharge cycles, the control unit 122 determines that the first condition is not satisfied. If the actual number of charge / discharge cycles is equal to the target number of charge / discharge cycles, the control unit 122 may execute the first control or may execute the second control. Note that two or more predetermined deterioration rates (e.g., 10%, 20%, 30%, etc.) may be set as the predetermined deterioration rate. It should be noted here that in a case where the actual number of charge / discharge cycles when the capacity degradation rate reaches a predetermined degradation rate is greater than the target number of charge / discharge cycles, the degradation of the capacity of the energy storage device 120 is relatively less advanced than in a case where the actual number of charge / discharge cycles when the capacity degradation rate reaches a predetermined degradation rate is less than the target number of charge / discharge cycles.

[0075] That is, in option 3-2, it is sufficient to intermittently determine whether the first condition is satisfied. In other words, before the number of charge / discharge cycles reaches a predetermined number of cycles, the determination of whether the first condition is satisfied may be omitted. Therefore, the processing load associated with the determination of whether the first condition is satisfied can be reduced.

[0076] As described above, the capacity deterioration rate may be replaced with another first parameter, and the number of charge / discharge cycles may be replaced with another second parameter. That is, option 3-2 may be expressed as shown below. A target for the second parameter to be satisfied when the first parameter reaches a predetermined parameter is defined. When the first parameter reaches the predetermined parameter, the control unit 122 determines whether the first condition is satisfied based on a comparison result between the actual performance of the second parameter and the target for the second parameter.

[0077] (Action and Effects) In the embodiment, the power storage device 120 executes a first control using a first DOD as the depth of discharge of the power storage device 120 when a first condition related to the deterioration of the power storage device 120 is not satisfied. The power storage device 120 executes a second control using a second DOD larger than the first DOD as the depth of discharge of the power storage device 120 when a first condition related to the deterioration of the power storage device 120 is satisfied. According to such a configuration, by appropriately using the first DOD and the second DOD, it is possible to provide flexibility in the operation of the power storage device 120 while taking into consideration the lifespan of the power storage device 120, as compared to a case in which the DOD is fixedly determined as one value.

[0078] [Change Example 1] Modification 1 of the embodiment will be described below, with differences from the embodiment being described below.

[0079] In the first modification, the control unit 122 of the power storage device 120 executes the second control when the second condition for starting the second control is satisfied and the first condition is satisfied. The following options are possible as the second condition.

[0080] In option 4-1, the second condition may be defined based on the power supply and demand balance of the power system 12 connected to the facility 100. For example, the second condition may be to receive a message (request or request) regarding maintaining the power supply and demand balance of the power system 12. Alternatively, the second condition may be to participate in maintaining the power supply and demand balance of the power system 12. Specifically, when a message (request or request) regarding maintaining the power supply and demand balance of the power system 12 is received, the control unit 122 may determine whether both the first condition and the second condition are satisfied. The control unit 122: Either the first or second condition is not met On the other hand, the control unit 122 executes the first control in this case. Both the first and second conditions are met In this case, the second control is executed.

[0081] The message regarding maintaining the balance between power supply and demand in the power system 12 may be received from the power management server 200 or from the EMS 160. The message may be a message instructing the suppression of power flow to the facility 100, or may be a message instructing an increase in reverse power flow from the facility 100. These messages may be messages regarding so-called DR (Demand Response). Alternatively, the message may be a message instructing an increase in power flow to the facility 100, or may be a message instructing the suppression of reverse power flow from the facility 100. These messages may be messages regarding so-called output suppression.

[0082] According to such a configuration, the power storage device 120 can be effectively used to maintain the balance between power supply and demand in the power system 12 by providing flexibility in the operation of the power storage device 120.

[0083] In option 4-2, the second condition may be defined based on a prediction of a power outage that may occur in an area including the facility 100. For example, the second condition may be that a power outage that may occur in an area including the facility 100 is predicted. Specifically, when the control unit 122 receives a message regarding a prediction of a power outage that may occur in an area including the facility 100, the control unit 122 may determine whether or not both the first condition and the second condition are satisfied. The control unit 122: Either the first or second condition is not met On the other hand, the control unit 122 executes the first control in this case. Both the first and second conditions are met In this case, the second control is executed.

[0084] The message regarding the prediction of a power outage that may occur in the area including the facility 100 may be received from the power management server 200 or from the EMS 160. Alternatively, the message regarding the prediction of a power outage that may occur in the area including the facility 100 may be received from an external server such as a weather server. The message may be a message regarding a prediction of a natural disaster such as a typhoon, heavy snow, or lightning. The message may be a message regarding a prediction of a planned power outage, or the like. The message may include an information element regarding the time when the power outage is predicted.

[0085] According to such a configuration, the operation of the power storage device 120 is made flexible, so that the power storage device 120 can be used effectively during a power outage.

[0086] Although not particularly limited, in option 4-2, the second control is a control to release the unusable area (charging), that is, the first threshold (upper threshold T UPPER ) to a second threshold value that is greater than the first threshold value (see FIG. 7).

[0087] In option 4-3, the second condition may be defined based on a prediction of the power consumption that may be consumed in the facility 100. For example, the second condition may be that the power consumption that may be consumed in the facility 100 is predicted to exceed a threshold. When the control unit 122 receives a message regarding a prediction that the power consumption that may be consumed in the facility 100 will exceed a threshold, the control unit 122 may determine whether both the first condition and the second condition are satisfied. The control unit 122: Either the first or second condition is not met On the other hand, the control unit 122 executes the first control in this case. Both the first and second conditions are met In this case, the second control is executed.

[0088] The message regarding a prediction that the power consumption that may be consumed in the facility 100 will exceed the threshold may be received from the power management server 200 or from the EMS 160. The message may include an information element regarding the time when the power consumption is predicted to exceed the threshold, and may include an information element regarding the magnitude of the power consumption.

[0089] According to such a configuration, the power storage device 120 can be operated flexibly, and thus the power storage device 120 can be used effectively during times when the facility 100 is consuming a large amount of power.

[0090] Although not particularly limited, in option 4-3, the second control is a control for releasing the unusable area (discharge), that is, the first threshold (lower limit threshold T LOWER ) to a second threshold value which is smaller than the first threshold value (see FIG. 8).

[0091] Two or more options selected from the above-mentioned options 4-1 to 4-3 may be combined. Also, the business operator or the user of the facility 100 may be allowed to select whether or not to adopt the above-mentioned options 4-1 to 4-3 as the second condition. Furthermore, apart from the above-mentioned options 4-1 to 4-3, the business operator or the user of the facility 100 may specify a date and time (period) such as summer, and the second control may be executed if the first condition is satisfied during that period.

[0092] [Other embodiments] Although the present invention has been described by the above-mentioned embodiment, the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art.

[0093] In the above disclosure, the case has been exemplified where the control unit that controls the power storage device 120 is the control unit 122 of the power storage device 120. However, the above disclosure is not limited to this. The control unit that controls the power storage device 120 may be the control unit 163 of the EMS 160, or the power management server 200. The control unit that controls the power storage device 120 may be a device management server (such as an Operation and Maintenance server) that manages maintenance information of the power storage device 120, etc.

[0094] 9 and 10 may be stored in advance in the control unit 122 of the power storage device 120. The ideal deterioration curve and the allowable deterioration curve may be stored in advance in the EMS 160, in the power management server 200, or in the device management server. The EMS 160, the power management server 200, or the device management server may transmit the ideal deterioration curve and the allowable deterioration curve to the power storage device 120.

[0095] Although not specifically mentioned in the above disclosure, the first parameter and the second parameter may be managed by the control unit 122 of the power storage device 120. The first parameter and the second parameter may be managed by the EMS 160 or may be managed by the power management server 200. The EMS 160 or the power management server 200 may transmit the first parameter and the second parameter to the power storage device 120.

[0096] Although not specifically mentioned in the above disclosure, the system capacity utilization rate may be calculated based on the second DOD.

[0097] Although not specifically mentioned in the above disclosure, at least a part of the functions of the EMS 160 may be executed by a server located on the network 11. In other words, the EMS 160 may be provided by a cloud service. [Explanation of symbols]

[0098] Reference Signs List 1...power management system, 11...network, 12...power system, 100...facility, 110...solar cell device, 120...power storage device, 121...BT, 122...control unit, 130...fuel cell device, 140...load device, 160...EMS, 161...first communication unit, 162...second communication unit, 163...control unit, 190...measuring device, 200...power management server

Claims

1. A power storage device installed in the facility; A control unit that controls the power storage device, The control unit is When the condition is not satisfied, a first control is executed in which a first depth of discharge is used as a depth of discharge of the power storage device; When the condition is satisfied, a second control is executed in which a second depth of discharge that is greater than the first depth of discharge is used as a depth of discharge of the power storage device; the conditions include a condition that a first condition is satisfied; the first condition is defined based on a first parameter related to deterioration of the power storage device and a second parameter related to use of the power storage device; the first parameter is one or more parameters selected from a temperature of the power storage device, a capacity deterioration rate of the power storage device, a deterioration state of the power storage device, and an effective capacity of the power storage device; a power system in which the second parameter is one or more parameters selected from an accumulated usage time of the power storage device, a number of charge / discharge cycles of the power storage device, an accumulated discharge power of the power storage device, and an accumulated charge power of the power storage device.

2. The power system of claim 1, wherein the conditions include a condition in which a second condition regarding the start of the second control is satisfied and the first condition is satisfied.

3. 3. The power system according to claim 2, wherein the second condition is defined based on at least one selected from a power supply and demand balance of a power grid connected to the facility, a prediction of a power outage that may occur in an area including the facility, and a prediction of power consumption that may be consumed by the facility.

4. A target for the first parameter is defined to be met when the second parameter reaches a predetermined parameter; 4. The power system according to claim 1, wherein the control unit determines whether or not the first condition is satisfied based on a comparison result between an actual performance of the first parameter and a target for the first parameter when the second parameter reaches the specified parameter.

5. A target for a second parameter is defined to be met when the first parameter reaches a predetermined parameter; 4. The power system according to claim 1, wherein the control unit determines whether or not the first condition is satisfied based on a comparison result between an actual performance of the second parameter and a target for the second parameter when the first parameter reaches the specified parameter.

6. A step A of controlling a power storage device installed in a facility, The step A includes: executing a first control using a first depth of discharge as a depth of discharge of the power storage device when the condition is not satisfied; and executing a second control in which a second depth of discharge greater than the first depth of discharge is used as a depth of discharge of the power storage device when the condition is satisfied; the conditions include a condition that a first condition is satisfied; the first condition is defined based on a first parameter related to deterioration of the power storage device and a second parameter related to use of the power storage device; the first parameter is one or more parameters selected from a temperature of the power storage device, a capacity deterioration rate of the power storage device, a deterioration state of the power storage device, and an effective capacity of the power storage device; The second parameter is one or more parameters selected from an accumulated usage time of the power storage device, a number of charge / discharge cycles of the power storage device, an accumulated discharge power of the power storage device, and an accumulated charge power of the power storage device.

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