Power storage device and power storage control device

Abstract

To provide a power storage device capable of suppressing a peak of reverse flow power to a power system.SOLUTION: A charge / discharge control section 15b included in a power storage device 15 derives time transition of a predicted value of surplus power that can be derived by subtracting load power of a power load 14 provided in a facility 10 from power generated by a solar cell device 13 in a future predetermined charging permitted time zone. The charging permitted time zone includes: a first time zone including a predicted maximum surplus time at which the surplus power is predicted to be at its maximum; and a second time zone earlier in time than the first time zone. In the second time zone, when the predicted value of the surplus power is larger than a predetermined target reverse flow power, the charge / discharge control section charges power, which can be derived by subtracting the target reverse flow power from the predicted value of the surplus power, in the power storage section 15a up to the maximum charging power that can be charged in the power storage section 15a, and when the predicted value of the surplus power is equal to or less than the predetermined target reverse flow power, the charge / discharge control section does not charge the power storage section 15a, but charges power same as the predicted value of the surplus power in the power storage section 15a up to the maximum charging power in the first time zone.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power storage device provided together with a solar cell device in a facility that can receive a supply of power from a power grid, and to a power storage control device that controls the operation of the power storage device. [Background technology]

[0002] There are systems in which solar cell devices and power storage devices are installed in facilities such as residences and offices. When many facilities equipped with such systems are connected to a power grid, the time periods when the power generated by the solar cell devices at each facility is high, i.e., the time periods when surplus power is generated at the facilities, are almost simultaneous, so the total amount of reverse flow power supplied from the many facilities to the power grid can become very large.

[0003] Various attempts have been made to reduce power consumption during peak hours of power consumption by power loads connected to the power grid (so-called peak cutting), but in order to stabilize the power grid, as mentioned above, it is also necessary to reduce extreme increases in power flowing back from facilities to the power grid.

[0004] Patent Document 1 (Patent Publication No. 7284559) describes suppressing extreme increases in the amount of electricity received from the power grid (peak cutting) in facilities equipped with solar cell devices and power storage devices, but does not describe suppressing extreme increases in the amount of electricity flowing back into the power grid.

[0005] Patent Document 2 (Japanese Patent No. 7073639) describes suppressing surplus power supplied to the power grid by reducing the power generated by power generation facilities and increasing the power demand of demand facilities (such as storage batteries). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7284559 [Patent Document 2] Patent No. 7073639 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 2 describes how surplus power supplied to the power grid can be reduced by charging a storage battery. However, the storage capacity of a typical power storage device is often smaller than the amount of surplus power generated in a facility in one day on sunny days, when the power generated by a solar cell device is high. Therefore, once the power storage device is fully charged, it cannot store any more power, and the surplus power flows back to the power grid.

[0008] Fig. 8 is a graph showing an example in which surplus power generated is charged at the maximum charging power that the power storage device can charge. In the figure, the dashed lines show the time trends of surplus power and power shortage, and the solid line shows the time trends of reverse flow power to the power grid. Note that the surplus power is a value that can be derived by subtracting the load power of the power load from the power generated by the solar cell device, and the power shortage is a value that can be derived by subtracting the power generated by the solar cell device from the load power of the power load.

[0009] As shown in the figure, at time t20, surplus power is generated and charging to the power storage device begins. Between time t20 and time t21, the generated surplus power is smaller than the maximum charging power of the power storage device, so all of the generated surplus power is charged to the power storage device. As a result, between time t20 and time t21, the reverse flow power is zero. Thereafter, after time t21, the generated surplus power becomes greater than the maximum charging power of the power storage device, so part of the surplus power is charged in the power storage device at the maximum charging power, and the remainder is reverse flowed to the power grid. At time t22, the power storage device is fully charged, and thereafter charging by the power storage device is no longer possible. As a result, between time t22 and time t23, all of the generated surplus power is reverse flowed to the power grid.

[0010] When charging is performed as shown in FIG. 8, charging to the power storage device cannot be performed at the predicted maximum surplus time tm, when the surplus power is greatest. This predicted maximum surplus time tm can be considered to be the time when the power generated by the solar cell device is greatest. Therefore, it is considered that the reverse flow power is greatest at approximately the same time period in many facilities connected to the power grid. In other words, the power supplied to the power grid by multiple facilities can become very large at the same time period, which could cause instability in the power supply and demand balance in the power grid.

[0011] The present invention has been made in view of the above-mentioned problems, and has an object to provide a power storage device and a power storage control device that can suppress peaks in reverse flow power to a power grid. [Means for solving the problem]

[0012] A characteristic configuration of the power storage device according to the present invention for achieving the above object is a power storage device provided together with a solar cell device in a facility that can receive power supply from a power grid, the power storage device comprising: a power storage unit and a charge / discharge control unit that controls charging and discharging of the power storage unit; The charge / discharge control unit deriving a time transition of a predicted value of surplus power that can be derived by subtracting load power of a power load installed in the facility from power generated by the solar battery device during a future predetermined charging permission time slot; the charging permission time period includes a first time period including a predicted maximum surplus time when the surplus power is predicted to be maximum within the charging permission time period, and a second time period that is temporally earlier than the first time period; In the second time period, if the predicted value of the surplus power is greater than a predetermined target reverse flow power, the power that can be derived by subtracting the target reverse flow power from the predicted value of the surplus power is charged to the storage unit, with the maximum charging power that the storage unit can charge as an upper limit, and if the predicted value of the surplus power is equal to or less than the target reverse flow power, the storage unit is not charged, and in the first time period, the power that is equal to the predicted value of the surplus power is charged to the storage unit, with the maximum charging power as an upper limit.

[0013] According to the above characteristic configuration, the charge / discharge control unit can charge the power storage unit based on the predicted value of surplus power, regardless of the surplus power that is actually generated. During a second time slot that precedes the first time slot including the predicted maximum surplus time, if the predicted value of surplus power is greater than a predetermined target reverse flow power, the charge / discharge control unit charges the power storage unit with the power calculated by subtracting the target reverse flow power from the predicted value of surplus power, with the maximum charging power that the power storage unit can charge as an upper limit. However, if the predicted value of surplus power is equal to or less than the target reverse flow power, the charge / discharge control unit does not charge the power storage unit. As a result, if the predicted value of surplus power is similar to the actual surplus power, the actual reverse flow power is expected to be similar to or less than the target reverse flow power. In other words, during the second time slot that precedes the first time slot including the predicted maximum surplus time, while allowing reverse flow power that is similar to or less than the target reverse flow power to occur, the charge / discharge control unit reduces the charging power to the power storage unit, i.e., lengthens the time required for the power storage unit to be fully charged. Furthermore, during the first time slot, which comes later in time, the charge / discharge control unit charges the storage unit with power equal to the predicted value of surplus power, with the maximum charging power as the upper limit. That is, when the predicted value of surplus power is large, the storage unit is charged with a large charging power, and when the predicted value of surplus power is small, the storage unit is charged with a small charging power. As a result, the effect of suppressing reverse flow power to the power grid can be made greater than during the second time slot. Therefore, it is possible to provide a power storage device that can suppress peaks of reverse power flow to the power grid.

[0014] Another characteristic configuration of the storage device of the present invention is that the charge / discharge control unit derives the time progression of the predicted value of the surplus power based on the predicted value of the power generated by the solar cell device for each of the multiple unit periods that make up the charging permission time period, which is derived based on the predicted amount of solar radiation at the solar cell device for each of the multiple unit periods that make up the charging permission time period, and the predicted value of the load power of the power load for each of the multiple unit periods that make up the charging permission time period.

[0015] According to the above characteristic configuration, the charge / discharge control unit can derive the time progression of the predicted value of surplus power based on the predicted value of the power generation power of the solar cell device, which is derived based on the predicted amount of solar radiation in the solar cell device, and the predicted value of the load power of the power load.

[0016] A characteristic configuration of the power storage control device according to the present invention for achieving the above object is a power storage control device that remotely controls the operation of a power storage device provided together with a solar cell device in each of a plurality of facilities that can receive power supply from a power grid, and the power storage device includes a power storage unit and a charge / discharge control unit that controls charging and discharging of the power storage unit; deriving a time transition of a predicted value of the total surplus power of a plurality of facilities, which can be derived by subtracting a total load power of a power load provided at each of the plurality of facilities from a total power generation power of the solar cell devices of the plurality of facilities during a future predetermined charging permission time slot; the charging permission time period includes a first time period including a predicted maximum surplus time at which a total amount of surplus power of the plurality of facilities is predicted to be the largest among the charging permission time periods, and a second time period that is temporally earlier than the first time period; During the second time period, if the predicted total value of the surplus power of the plurality of facilities is greater than a predetermined target total reverse flow power, the power that can be derived by subtracting the target total reverse flow power from the predicted total value of the surplus power of the plurality of facilities is totaled and charged in the storage units of the plurality of facilities, with the maximum total charging power that the storage units of the plurality of facilities can charge in total as an upper limit; if the predicted total value of the surplus power of the plurality of facilities is equal to or less than the target total reverse flow power, the storage units of the plurality of facilities are not charged; and during the first time period, the same power as the predicted total value of the surplus power of the plurality of facilities is totaled and charged in the storage units of the plurality of facilities, with the maximum total charging power as an upper limit.

[0017] According to the above characteristic configuration, the power storage control device can charge the power storage units of multiple facilities based on a predicted value of the total surplus power of the multiple facilities, regardless of the surplus power actually generated. Then, during a second time slot that is temporally earlier than a first time slot that includes the predicted maximum surplus time, if the predicted value of the total surplus power of the multiple facilities is greater than a predetermined target total reverse flow power, the power storage control device causes the power storage units of the multiple facilities to add up and charge the power derived by subtracting the target total reverse flow power from the predicted value of the total surplus power of the multiple facilities, with the maximum total charging power that the power storage units of the multiple facilities can charge in total as an upper limit, and does not cause the power storage units of the multiple facilities to charge the power if the predicted value of the total surplus power of the multiple facilities is equal to or less than the target total reverse flow power. As a result, if the predicted value of the total surplus power of the multiple facilities is similar to the actual total surplus power of the multiple facilities, the total actual reverse flow power of the multiple facilities is expected to be similar to or less than the target total reverse flow power. In other words, during the second time period that is earlier than the first time period that includes the predicted maximum surplus time, the total reverse flow power in the multiple facilities is allowed to be equal to or less than the target total reverse flow power, while the charging power to the storage units of the multiple facilities is reduced, i.e., the period required for the storage units of the multiple facilities to reach a fully charged state is lengthened. Furthermore, during a later first time slot, the power storage control device charges the power storage units of the multiple facilities with power equal to the predicted total value of surplus power of the multiple facilities, with the maximum total charging power as the upper limit. That is, when the predicted total value of surplus power of the multiple facilities is large, the power storage control device can charge the power storage units of the multiple facilities with large charging power, and when the predicted total value of surplus power is small, the power storage control device can charge the power storage units of the multiple facilities with small charging power. As a result, the effect of suppressing reverse flow power to the power grid by the multiple facilities can be made greater than during the second time slot. Therefore, it is possible to provide a power storage control device that can suppress peaks of reverse power flow to the power grid.

[0018] Another characteristic configuration of the storage control device of the present invention is that it derives the time progression of the predicted value of the total surplus power of the multiple facilities based on the predicted value of the total power generation of the solar cell devices of the multiple facilities for each of the multiple unit periods that constitute the charging permission time period, which is derived based on the predicted amount of solar radiation at each of the solar cell devices of the multiple facilities for each of the multiple unit periods that constitute the charging permission time period, and the predicted value of the total load power of the power load of the multiple facilities for each of the multiple unit periods that constitute the charging permission time period.

[0019] According to the above characteristic configuration, the storage control device can derive the time progression of the predicted value of the total surplus power of the facility based on the predicted value of the total power generation of the solar cell devices of the multiple facilities, which is derived based on the predicted amount of solar radiation for each of the solar cell devices of the multiple facilities, and the predicted value of the total load power of the power loads of the multiple facilities. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram showing the configuration of a facility in which a power storage device of a first embodiment is installed. [Figure 2] 10 is an example of a time transition of a power shortage and a power surplus. [Figure 3] 10 is an example of time transition of power shortage, power surplus, and reverse flow power. [Figure 4] 10 is an example of time transition of power shortage, power surplus, and reverse flow power. [Figure 5] FIG. 1 is a diagram showing a configuration of a system including a plurality of facilities in which power storage devices are installed. [Figure 6] 10 is an example of a time transition of the sum of a power shortage, a power surplus, and a reverse flow power. [Figure 7] 10 is an example of a time transition of the sum of a power shortage, a power surplus, and a reverse flow power. [Figure 8] 10 is an example of time transition of power shortage, power surplus, and reverse flow power. DETAILED DESCRIPTION OF THE INVENTION

[0021] First Embodiment A power storage device 15 according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a facility 10 in which a power storage device 15 of this embodiment is installed. As shown in the figure, a power line 12 installed in facility 10, such as a residence or a business, is connected to a power grid 1. In facility 10, a solar cell device 13, a power storage device 15, and a power load 14 are connected to power line 12. In this manner, power storage device 15 is installed together with solar cell device 13 in facility 10 that can receive a supply of power from power grid 1. Devices such as power storage device 15 installed in facility 10 can be connected to an information communication line 2 outside facility 10 via router 11.

[0022] The power storage device 15 includes a power storage unit 15a and a charge / discharge control unit 15b that controls charging and discharging of the power storage unit 15a. In this embodiment, the power storage device 15 also includes a storage unit 15c that stores information. The power storage unit 15a can be realized using a device that can charge and discharge power, such as a secondary battery.

[0023] The solar cell device 13 can be realized using an element that converts light energy into electrical energy. Although not shown, the solar cell device 13 also includes a power conversion circuit that converts the power output from the element into a desired power.

[0024] The power load 14 is various devices that consume power, such as lighting equipment and air conditioning equipment, that are installed in the facility 10.

[0025] The measurement results of the power measurement unit 16 provided on the power line 12 are transmitted to the power storage device 15. The power measured by the power measurement unit 16 is the power supplied from the power system 1 to the power line 12 of the facility 10. In this embodiment, the solar cell device 13, the power storage device 15, and the power load 14 are connected to the power line 12, and therefore the power measured by the power measurement unit 16 is the value obtained by subtracting the power generated by the solar cell device 13 and the discharge power of the power storage device 15 from the load power of the power load 14. Alternatively, the power measured by the power measurement unit 16 is the value obtained by subtracting the power generated by the solar cell device 13 from the load power of the power load 14 and the charging power of the power storage device 15.

[0026] The charge / discharge control unit 15b of the power storage device 15 knows the discharge power that the power storage unit 15a discharges to the power line 12 or the charge power that the power storage unit 15a charges from the power line 12, and therefore can refer to the measurement results of the power measurement unit 16 to determine the surplus power that can be derived by subtracting the load power of the power load 14 from the power generated by the solar cell device 13, or the shortage power (i.e., negative surplus power) that can be derived by subtracting the power generated by the solar cell device 13 from the load power of the power load 14. Then, the charge / discharge control unit 15b stores information indicating the time transition of the shortage power and surplus power generated in the facility 10 in the memory unit 15c.

[0027] The measurement results of power measurement unit 17 provided on power line 12 are transmitted to power storage device 15. The power measured by power measurement unit 17 is a value obtained by subtracting the discharge power of power storage device 15 from the load power of power load 14. Alternatively, the power measured by power measurement unit 17 is a value obtained by adding the load power of power load 14 and the charge power of power storage device 15. Because charge / discharge control unit 15b knows the discharge power discharged by power storage unit 15a to power line 12 or the charge power charged from power line 12, it can determine the load power of power load 14 by referring to the measurement results of power measurement unit 17. Then, charge / discharge control unit 15b stores information indicating the time transition of the load power of power load 14 in memory unit 15c.

[0028] The power storage device 15 can acquire information on the time transition of the predicted amount of solar radiation via the information communication line 2 from the information providing server 3, which provides information on the time transition of the predicted amount of solar radiation. For example, if a predetermined charging permission time period is set, such as from 6:00 to 18:00, the power storage device 15 can acquire information on the predicted amount of solar radiation for each of multiple unit periods (e.g., every 30 minutes, every hour, etc.) that make up the charging permission time period. In addition, the storage unit 15c stores a program that derives a predicted value of the power generated by the solar cell device 13 for each unit period based on the predicted amount of solar radiation for the unit period. Therefore, the charge / discharge control unit 15b can derive a predicted value of the power generated by the solar cell device 13 for each of multiple unit periods that make up the charging permission time period based on the predicted amount of solar radiation for each of the multiple unit periods that make up the charging permission time period.

[0029] As described above, the charge / discharge control unit 15b stores information indicating the time transition of the load power of the power load 14 in the storage unit 15c. For example, the past load power data stored in the storage unit 15c includes information about the time transition of the load power for each unit period, such as the past four weeks, along with attribute data such as the day of the week, weekday, and holiday. As a result, the charge / discharge control unit 15b can derive, for example, a predicted value of the load power for each unit period constituting the charging permission time slot of the next day, by referring to the past load power data.

[0030] In this way, the charge / discharge control unit 15b can derive the predicted value of the power generated by the solar cell device 13 for each of the plurality of unit periods constituting the charging permission time slot and the predicted value of the load power for each unit period. As a result, the charge / discharge control unit 15b can derive the time transition of the predicted value of the surplus power based on the predicted value of the power generated by the solar cell device 13 for each of the plurality of unit periods derived based on the predicted amount of solar radiation at the solar cell device 13 for each of the plurality of unit periods constituting the future predetermined charging permission time slot and the predicted value of the load power of the power load 14 for each of the plurality of unit periods constituting the charging permission time slot.

[0031] For example, if the weather is sunny, the amount of solar radiation increases and the power generated by the solar cell device 13 on that day increases, and if the weather is rainy or the like, the amount of solar radiation decreases and the power generated by the solar cell device 13 on that day decreases. Therefore, if the weather is sunny and the amount of solar radiation is large, i.e., if the power generated by the solar cell device 13 is large, the surplus power will be large (or the power shortage will be small). On the other hand, if the weather is rainy or the like and the amount of solar radiation is small, i.e., if the power generated by the solar cell device 13 is small, the surplus power will be small (or the power shortage will be large).

[0032] Furthermore, when the power generated by the solar cell device 13 increases, the surplus power that can be derived by subtracting the load power of the power load 14 from the power generated by the solar cell device 13 increases (or the deficit power that can be derived by subtracting the power generated by the solar cell device 13 from the load power of the power load 14 decreases), and when the power generated by the solar cell device 13 decreases, the surplus power that can be derived by subtracting the load power of the power load 14 from the power generated by the solar cell device 13 decreases (or the deficit power that can be derived by subtracting the power generated by the solar cell device 13 from the load power of the power load 14 increases).

[0033] Fig. 2 shows an example of time trends in the predicted values ​​of power shortage and power surplus that will occur in facility 10. In Fig. 2, the dashed lines show an example of time trends in the predicted values ​​of power shortage and power surplus on days when the predicted value of power generation by solar cell device 13 is large, and the dashed-dotted lines show an example of time trends in the predicted values ​​of power shortage and power surplus on days when the predicted value of power generation by solar cell device 13 is small. As shown in the figure, on days when the power generation by solar cell device 13 is large, the surplus power is large and the power shortage is small, and on days when the power generation by solar cell device 13 is small, the surplus power is small and the power shortage is large.

[0034] The charge / discharge control unit 15b can set the unit period in which the predicted value of power generation by the solar cell device 13 is maximum among the derived multiple unit periods as the predicted maximum surplus period in which surplus power is predicted to be maximum within the charging permission time slot. Furthermore, the charge / discharge control unit 15b can set a predetermined time (e.g., a midpoint time) within the predicted maximum surplus period as the predicted maximum surplus time in which surplus power is predicted to be maximum within the charging permission time slot. For example, if the unit period in which the predicted value of power generation by the solar cell device 13 is maximum is the period from 1:00 PM to 2:00 PM, the charge / discharge control unit 15b can set this period as the predicted maximum surplus period. Furthermore, the charge / discharge control unit 15b can set 1:30 PM, which is the midpoint of the predicted maximum surplus period from 1:00 PM to 2:00 PM, as the predicted maximum surplus time. In FIG. 2, the predicted maximum surplus time tm is shown for days when the predicted value of power generation by the solar cell device 13 is large (dashed line) and days when the predicted value of power generation by the solar cell device 13 is small (chain dotted line).

[0035] The power storage device 15 can be charged with power from the power line 12. Therefore, in the power storage device 15, a predetermined time period during which the solar cell device 13 can generate power is stored in the storage unit 15c as a charging-permitted time period during which the power storage unit 15a can charge with power from the power line 12. In FIG. 2, the period from 6:00 to 18:00 is set as the charging-permitted time period. In this embodiment, the charging-permitted time period includes a first time period including a predicted maximum surplus time at which surplus power is predicted to be greatest within the charging-permitted time period, and a second time period that precedes the first time period. In the example shown in FIG. 3, which will be described later, the charge / discharge control unit 15b sets a first time period including a predicted maximum surplus time tm and a second time period that does not include the predicted maximum surplus time tm. For example, the charge / discharge control unit 15b sets the first time period from time t2, which is a set time (for example, 1 hour and 30 minutes) before the predicted maximum surplus time tm, to the last time (6:00 p.m.) of the charging permission time period, and sets the second time period from the first time (6:00 a.m.) of the charging permission time period that is temporally before the first time period to time t2.

[0036] Then, in the second time slot, when the predicted value of surplus power is greater than a predetermined target backward flow power, charge / discharge control unit 15b causes power storage unit 15a to charge with power that can be derived by subtracting the target backward flow power from the predicted value of surplus power, with the maximum charging power that power storage unit 15a can charge as an upper limit. On the other hand, when the predicted value of surplus power is equal to or less than the target backward flow power, charge / discharge control unit 15b does not cause power storage unit 15a to charge.

[0037] 3 shows an example of time transitions of the predicted values ​​of power shortage, power surplus, and reverse flow power from facility 10 to power grid 1 on a day when the predicted value of power generation by solar cell device 13 is small. In this case, between time t1 and time t2 in the second time slot, the predicted value of surplus power is always equal to or less than the target reverse flow power, so charge / discharge control unit 15b does not allow power storage unit 15a to charge. As a result, between time t1 and time t2, it is predicted that the reverse flow power (predicted value) indicated by the solid line will be supplied to power grid 1.

[0038] Furthermore, during the first time slot from time t2 to time 18:00, charge / discharge control unit 15b charges power storage unit 15a with the same power as the predicted value of surplus power, with the maximum charge power as the upper limit. In the example shown in Fig. 3, during the time slot from time t2 to time t3, charge is performed to power storage unit 15a with target charge power equal to the predicted value of surplus power. As a result, it is predicted that the backward flow power will be zero.

[0039] 4 shows an example of time transitions of the predicted values ​​of power shortage, power surplus, and reverse flow power from facility 10 to power grid 1 on a day when the predicted value of power generation by solar cell device 13 is large. In the example shown in FIG. 4, the first time slot is from time t6 to time 18:00, and the second time slot is from time 6:00 to time t6. During the second time slot, from time t4 to time t5, the predicted value of surplus power is equal to or less than the target reverse flow power, so charge / discharge control unit 15b does not charge power storage unit 15a. As a result, the reverse flow power (predicted value) shown by the solid line is predicted to be supplied to power grid 1.

[0040] Thereafter, between time t5 and time t6 in the second time slot, the predicted value of surplus power is greater than the target backward flow power, so charge / discharge control unit 15b charges power storage unit 15a with a second target charge power (i.e., surplus power equal to or greater than the target backward flow power) that can be derived by subtracting the target backward flow power from the predicted value of surplus power, with the maximum charge power that power storage unit 15a can charge as the upper limit. As a result, between time t5 and time t6, the backward flow power (predicted value) supplied to power system 1 is predicted to be equal to the target backward flow power.

[0041] Furthermore, during the first time slot between time t6 and time t8, the charge / discharge control unit 15b charges the power storage unit 15a with power (first target charge power) that is equal to or smaller than the predicted value of surplus power, with the maximum charge power as the upper limit. As a result, in the example shown in FIG. 4, during the first time slot between time t6 and time t7, it is predicted that the backward flow power (predicted value) that can be derived by subtracting the first target charge power from the predicted value of surplus power will be supplied to the power system 1, and during the time slot between time t7 and time t8, it is predicted that the backward flow power (predicted value) indicated by the solid line will be zero. In this way, the power storage device 15 of this embodiment can reduce the backward flow power at the predicted maximum surplus time tm, when the surplus power is predicted to be at its maximum. In other words, this can contribute to stabilizing the power system 1.

[0042] As described above, charge / discharge control unit 15b can charge power storage unit 15a based on the predicted value of surplus power, regardless of the surplus power actually generated. During the second time slot that is earlier than the first time slot including the predicted maximum surplus time, if the predicted value of surplus power is greater than a predetermined target backward flow power, charge / discharge control unit 15b charges power storage unit 15a with the power that can be derived by subtracting the target backward flow power from the predicted value of surplus power, with the maximum charging power that power storage unit 15a can charge as an upper limit. However, if the predicted value of surplus power is equal to or less than the target backward flow power, charge / discharge control unit 15b does not charge power storage unit 15a. As a result, if the predicted value of surplus power is similar to the actual surplus power, it is expected that the actual backward flow power will also be similar to or less than the target backward flow power. That is, in the second time slot, which is earlier than the first time slot including the predicted maximum surplus time, the generation of reverse flow power equal to or less than the target reverse flow power is permitted, while the charging power to the power storage unit 15a is reduced, i.e., the period required for the power storage unit 15a to reach a fully charged state is lengthened. Furthermore, in the later first time slot, the charge / discharge control unit 15b charges the power storage unit 15a with the same power as the predicted value of surplus power, with the maximum charging power as the upper limit. That is, when the predicted value of surplus power is large, the charging power to the power storage unit 15a is increased, and when the predicted value of surplus power is small, the charging power to the power storage unit 15a is decreased. As a result, the suppression effect of reverse flow power to the power grid 1 can be increased more than in the second time slot.

[0043] Second Embodiment In the second embodiment, a power storage control device 4 that remotely controls the operation of a power storage device 15 provided together with a solar cell device 13 in each of a plurality of facilities 10 that can receive power supply from a power grid 1 will be described.

[0044] FIG. 5 is a diagram showing the configuration of a system in which a power storage control device 4 is provided. As shown in the figure, a plurality of facilities 10 (10A, 10B, 10C) having the same configuration as that of the first embodiment are connected to a power grid 1. Specifically, in each of the plurality of facilities 10, a solar cell device 13, a power storage device 15, and a power load 14 are connected to a power line 12. Each facility 10 can communicate information with the power storage control device 4 via an information communication line 2. An information providing server 3 is also connected to the information communication line 2. The power storage control device 4 remotely controls the operation of the power storage device 15 provided together with the solar cell device 13 in each of the plurality of facilities 10 that can receive power supply from the power grid 1. Although three facilities 10A to 10C are shown in FIG. 5, the number can be changed as appropriate. The power storage control device 4 can be realized using, for example, a server.

[0045] As in the first embodiment, the power storage device 15 includes a power storage unit 15a and a charge / discharge control unit 15b that controls charging and discharging of the power storage unit 15a. The power storage device 15 also includes a storage unit 15c that stores information.

[0046] In each facility 10, the charge / discharge control unit 15b of the power storage device 15 stores, in the memory unit 15c, information indicating the time transition of the power shortage and surplus power occurring in the facility 10 and information indicating the time transition of the load power of the power load 14. Furthermore, the charge / discharge control unit 15b can derive a predicted value of the power generation power of the solar cell device 13 for each of the multiple unit periods constituting the charging permission time slot, based on the predicted amount of solar radiation for each of the multiple unit periods constituting the charging permission time slot.

[0047] For example, the past load power data stored in the storage unit 15c includes information about the time transition of the load power for each unit period, such as the past four weeks, along with attribute data such as the day of the week, weekday, and public holiday. As a result, the charge / discharge control unit 15b can refer to the past load power data and derive, for example, a predicted value of the load power for each unit period that constitutes the charging permission time slot of the next day.

[0048] In this way, the charge / discharge control unit 15b can derive a predicted value of the power generated by the solar cell device 13 for each of the multiple unit periods constituting the charging permission time slot, and a predicted value of the load power for each unit period. As a result, the charge / discharge control unit 15b can derive a time transition of a predicted value of surplus power that can be derived by subtracting the load power of the power load 14 installed in the facility 10 from the power generated by the solar cell device 13 during a predetermined future charging permission time slot.

[0049] Then, the charge / discharge control unit 15b transmits information regarding the time progression of the predicted value of surplus power that can be derived by subtracting the load power of the power load 14 installed in the facility 10 from the power generated by the solar cell device 13 during a specified future charging permission time period to the storage control device 4 via the information communication line 2.

[0050] Based on the time progression of the predicted value of surplus power at each facility 10 received from the multiple facilities 10, the storage control device 4 derives the time progression of the predicted value of total surplus power at the multiple facilities 10, which can be derived by subtracting the total load power of the power loads 14 installed at each of the multiple facilities 10 from the total generated power of the solar cell devices 13 at the multiple facilities 10 during a specified future charging permission time period.

[0051] The power storage control device 4 may acquire information on the predicted amount of solar radiation for each of a plurality of unit periods constituting a future charging permission time slot at the plurality of facilities 10 from the information providing server 3 via the information communication line 2. Then, the power storage control device 4 may derive a predicted value of the power generation capacity of the photovoltaic devices 13 of the plurality of facilities 10 for each of a plurality of unit periods constituting a charging permission time slot based on the acquired information. Furthermore, the power storage control device 4 may derive a time transition of a predicted value of the total amount of surplus power of the plurality of facilities 10, which can be derived by subtracting the total load power of the power loads 14 installed in each of the plurality of facilities 10 from the total power generation capacity of the photovoltaic devices 13 of the plurality of facilities 10 during a predetermined future charging permission time slot.

[0052] In this way, the storage control device 4 can derive the time progression of the predicted value of the total surplus power of the multiple facilities 10 based on the predicted value of the total power generation of the solar cell devices 13 of the multiple facilities 10 for each of the multiple unit periods that constitute the charging permission time zone, which is derived based on the predicted amount of solar radiation at each of the solar cell devices 13 of the multiple facilities 10 for each of the multiple unit periods that constitute the charging permission time zone, and the predicted value of the total load power of the power loads 14 of the multiple facilities 10 for each of the multiple unit periods that constitute the charging permission time zone.

[0053] FIG. 6 shows an example of time transitions of predicted values ​​of the total power shortage, the total surplus power, and the total reverse flow power from the facilities 10 to the power grid 1 on a day when the predicted value of power generation by the solar cell device 13 is small. In FIG. 6, the time transitions of the predicted value of the total power shortage and the predicted value of the total surplus power of the multiple facilities 10 are indicated by dashed dotted lines, and the time transitions of the predicted value of the total reverse flow power of the multiple facilities 10 are indicated by solid lines. In this embodiment, the charging permission time slot includes a first time slot including a predicted maximum surplus time at which the total surplus power of the multiple facilities 10 is predicted to be the largest among the charging permission time slots, and a second time slot that precedes the first time slot. In the example shown in FIG. 6, the power storage control device 4 sets a first time slot that includes a predicted maximum surplus time tm and a second time slot that does not include the predicted maximum surplus time tm. For example, the power storage control device 4 sets the first time slot from a time a set time (for example, 1 hour and 30 minutes) before the predicted maximum surplus time tm to the last time of the charging permission time slot, and sets the time slot temporally before the first time slot as the second time slot. For example, the second time slot is set between 6:00 and t10, and the first time slot is set between t10 and 18:00.

[0054] In this embodiment, during the second time slot, if the predicted value of the total surplus power of the multiple facilities 10 is greater than a predetermined target total reverse flow power, the power storage control device 4 causes the power storage units 15a of the multiple facilities 10 to charge the total amount of power derived by subtracting the target total reverse flow power from the predicted value of the total surplus power of the multiple facilities 10, with the maximum total charging power that the power storage units 15a of the multiple facilities 10 can charge in total as an upper limit, and does not cause the power storage units 15a of the multiple facilities 10 to charge the total amount of power derived by subtracting the target total reverse flow power from the predicted value of the total surplus power of the multiple facilities 10 if the predicted value of the total surplus power of the multiple facilities 10 is equal to or less than the target total reverse flow power. Moreover, during the first time slot, the power storage control device 4 causes the power storage units 15a of the multiple facilities 10 to charge the total amount of power equal to the predicted value of the total surplus power of the multiple facilities 10, with the maximum total charging power as an upper limit.

[0055] In order to charge the power storage units 15a of the multiple facilities 10 in total, it is necessary to distribute the total charging power (e.g., charging power per unit period) of the power storage units 15a of the multiple facilities 10 determined as described above to the charging power (e.g., charging power per unit period) of the power storage units 15a of each facility 10 and transmit the distributed charging power to the power storage devices 15 of the multiple facilities 10. For example, the power storage control device 4 distributes the total charging power of the power storage units 15a of the multiple facilities 10 determined as described above evenly among the multiple facilities 10 and transmits the distributed charging power of the power storage units 15a to each facility 10 via the information communication line 2. Then, the charge / discharge control unit 15b of the power storage device 15 of each facility 10 charges the power storage unit 15a with the charging power (e.g., charging power per unit period) transmitted from the power storage control device 4. Furthermore, the method of distributing the determined "total charging power of the storage units 15a of the multiple facilities 10" to "each charging power of the multiple facilities 10" is not limited to the equal distribution described above, and can be changed as appropriate.

[0056] 6, during the second time slot between time t9 and time t10, the predicted total value of surplus power of the multiple facilities 10 is always equal to or less than the target total backward flow power, and therefore the power storage control device 4 does not charge the power storage unit 15a of the power storage device 15 of each facility 10. As a result, it is predicted that the total backward flow power (predicted value) indicated by the solid line will be supplied from the multiple facilities 10 to the power grid 1.

[0057] Furthermore, during the first time slot between time t10 and time t11, the power storage control device 4 charges the power storage units 15a of the power storage devices 15 in each facility 10 with power equal to the predicted value of the total surplus power, with the maximum total charging power as the upper limit. In the example shown in Fig. 6, during the first time slot between time t10 and time t11, the power storage units 15a of the power storage devices 15 in the plurality of facilities 10 are charged with target total charging power equal to the predicted value of surplus power. As a result, the total reverse flow power is predicted to be zero.

[0058] Fig. 7 shows an example of the time progression of the predicted values ​​of the total power shortage, the total surplus power, and the total reverse flow power from the facilities 10 to the power grid 1 on a day when the predicted value of the power generated by the solar cell device 13 is large. In Fig. 7, the time progression of the predicted values ​​of the total power shortage and the total surplus power is indicated by a dashed line, and the time progression of the predicted value of the total reverse flow power is indicated by a solid line. In the example shown in Fig. 7, the power storage control device 4 sets a first time slot that includes the predicted maximum surplus time tm and a second time slot that does not include the predicted maximum surplus time tm.

[0059] 7, during the second time slot between time t12 and time t13, the predicted total value of surplus power of the multiple facilities 10 is equal to or less than the target total backward flow power, and therefore the power storage control device 4 does not charge the power storage units 15a of the multiple facilities 10. As a result, it is predicted that the total backward flow power indicated by the solid line will be supplied from the multiple facilities 10 to the power grid 1.

[0060] Thereafter, between time t13 and time t14 in the second time slot, the predicted value of the surplus power of the multiple facilities 10 is greater than the target total reverse flow power, and therefore the power storage control device 4 causes the power storage units 15a of the multiple facilities 10 to add up and charge a second target total charging power (i.e., power equal to or greater than the target total reverse flow power) that can be derived by subtracting the target total reverse flow power from the predicted value of the total surplus power of the multiple facilities 10, with the upper limit set to the maximum total charging power that can be charged in total by the power storage units 15a of the multiple facilities 10. As a result, between time t13 and time t14, the total reverse flow power (predicted value) supplied from the multiple facilities 10 to the power grid 1 is predicted to be equal to the target total reverse flow power.

[0061] Furthermore, during a first time slot from time t14 to time t16, the power storage control device 4 causes the power storage units 15a of the multiple facilities 10 to store power (first target total charging power) that is equal to or smaller than the predicted value of the total surplus power, with the upper limit set to the maximum total charging power that can be charged in total by the power storage units 15a of the multiple facilities 10. In the example shown in Fig. 7, during the first time slot from time t14 to time t15, it is predicted that the total backward flow power that can be derived by subtracting the first target total charging power from the predicted value of the total surplus power will be supplied from the multiple facilities 10 to the power grid 1, and during the time slot from time t15 to time t16, it is predicted that the total backward flow power (predicted value) indicated by the solid line will be zero.

[0062] As described above, the power storage control device 4 can cause the power storage units 15a of the multiple facilities 10 to be charged based on the predicted value of the total surplus power of the multiple facilities 10, regardless of the surplus power actually generated. Then, during the second time slot that is temporally earlier than the first time slot that includes the predicted maximum surplus time, if the predicted value of the total surplus power of the multiple facilities 10 is greater than a predetermined target total reverse flow power, the power storage control device 4 causes the power storage units 15a of the multiple facilities 10 to add up and charge the power that can be derived by subtracting the target total reverse flow power from the predicted value of the total surplus power of the multiple facilities 10, with the maximum total charging power that the power storage units 15a of the multiple facilities 10 can charge in total as an upper limit, and does not cause the power storage units 15a of the multiple facilities 10 to charge if the predicted value of the total surplus power of the multiple facilities 10 is equal to or less than the target total reverse flow power. As a result, if the predicted value of the total surplus power of the multiple facilities 10 is similar to the actual total surplus power of the multiple facilities 10, the total actual reverse flow power of the multiple facilities 10 is expected to be similar to or less than the target total reverse flow power. In other words, during the second time slot that is temporally earlier than the first time slot including the predicted maximum surplus time, the total reverse flow power of the multiple facilities 10 is allowed to be similar to or less than the target total reverse flow power, while the charging power to the power storage units 15a of the multiple facilities 10 is reduced, that is, the period required for the power storage units 15a of the multiple facilities 10 to reach a fully charged state is lengthened. Furthermore, during the later first time slot, the power storage control device 4 charges the power storage units 15a of the multiple facilities 10 with power equal to the predicted value of the total surplus power of the multiple facilities 10, with the maximum total charging power as the upper limit. That is, when the predicted value of the total surplus power of the multiple facilities 10 is large, the power storage units 15a of the multiple facilities 10 can be charged with large charging power, and when the predicted value of the total surplus power is small, the power storage units 15a of the multiple facilities 10 can be charged with small charging power. As a result, the effect of suppressing reverse flow power to the power grid 1 by the multiple facilities 10 can be made greater than in the second time slot.

[0063] <Another embodiment> In the above embodiment, the configuration of the storage device 15, the configuration of the storage control device 4, and the configuration of the system in which the solar cell device 13 and the storage device 15 are installed in the facility 10 are specifically described, but these configurations can be changed as appropriate.

[0064] In the above embodiment, an example has been described in which information handled by the power storage device 15, such as information indicating the time transition of power shortages and surpluses generated in the facility 10, information indicating the time transition of the load power of the power load 14, information about a program that derives a predicted value of the power generated by the solar cell device 13 for a unit period based on the predicted amount of solar radiation for the unit period, and information about a charging permission time period during which the power storage unit 15a can charge power from the power line 12, is stored in the memory unit 15c of the power storage device 15. However, such information may be stored in a single memory device separate from the power storage device 15 or may be stored separately in multiple devices. For example, such information may be stored in a memory unit of a server (not shown) connected to the information communication line 2, and in the first embodiment, the power storage device 15 may access the server to acquire the information. In the second embodiment, the power storage control device 4 may store such necessary information in its own memory unit (not shown), or may access information stored in a separate server to acquire the necessary information.

[0065] In the above embodiment, the power storage device 15 and the power storage control device 4 of the present invention have been described using numerical examples, but these numerical values ​​have been given for illustrative purposes and can be changed as appropriate.

[0066] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0067] INDUSTRIAL APPLICABILITY The present invention can be used for a power storage device and a power storage control device that can suppress peaks of reverse flow power to a power grid. [Explanation of symbols]

[0068] 1: Power system 2: Information and communication lines 3: Information server 4: Storage control device 10 (10A-10C): Facilities 11: Router 12: Power lines 13: Solar cell device 14: Power load 15: Power storage device 15a: Power storage unit 15b: Charge / discharge control unit 15c: Storage section 16: Power measurement section 17: Power measurement section

Claims

1. A power storage device provided together with a solar cell device in a facility that can receive power from a power grid, a power storage unit and a charge / discharge control unit that controls charging and discharging of the power storage unit; The charge / discharge control unit deriving a time transition of a predicted value of surplus power that can be derived by subtracting load power of a power load installed in the facility from power generated by the solar battery device during a future predetermined charging permission time slot; the charging permission time period includes a first time period including a predicted maximum surplus time at which the surplus power is predicted to be maximum within the charging permission time period, and a second time period that is temporally earlier than the first time period; The energy storage device charges the energy storage unit with power that can be derived by subtracting the target reverse flow power from the predicted value of the surplus power, with an upper limit of a maximum charging power that the energy storage unit can charge, when the predicted value of the surplus power is greater than a predetermined target reverse flow power during the second time period; does not charge the energy storage unit when the predicted value of the surplus power is equal to or less than the target reverse flow power; and charges the energy storage unit with power that is equal to the predicted value of the surplus power, with an upper limit of the maximum charging power during the first time period.

2. 2. The power storage device according to claim 1, wherein the charge / discharge control unit derives a time progression of the predicted value of the surplus power based on a predicted value of the power generated by the solar cell device for each of a plurality of unit periods that constitute the charging permission time period, the predicted value being derived based on a predicted amount of solar radiation at the solar cell device for each of the plurality of unit periods that constitute the charging permission time period, and a predicted value of the load power of the power load for each of the plurality of unit periods that constitute the charging permission time period.

3. A power storage control device that remotely controls the operation of a power storage device provided together with a solar cell device in each of a plurality of facilities that can receive power supply from a power grid, the power storage device includes a power storage unit and a charge / discharge control unit that controls charging and discharging of the power storage unit; deriving a time transition of a predicted value of the total surplus power of a plurality of facilities, which can be derived by subtracting a total load power of a power load provided at each of the plurality of facilities from a total power generation power of the solar cell devices of the plurality of facilities during a future predetermined charging permission time slot; the charging permission time period includes a first time period including a predicted maximum surplus time at which a total amount of surplus power of the plurality of facilities is predicted to be the largest among the charging permission time periods, and a second time period that is temporally earlier than the first time period; and a power storage control device that, during the second time period, if the predicted value of the total surplus power of the plurality of facilities is greater than a predetermined target total reverse flow power, causes the power storage units of the plurality of facilities to add up and charge power that can be derived by subtracting the target total reverse flow power from the predicted value of the total surplus power of the plurality of facilities, with an upper limit of a maximum total charging power that the power storage units of the plurality of facilities can charge in total; and, when the predicted value of the total surplus power of the plurality of facilities is equal to or less than the target total reverse flow power, does not cause the power storage units of the plurality of facilities to charge; and, during the first time period, causes the power storage units of the plurality of facilities to add up and charge power that is equal to the predicted value of the total surplus power of the plurality of facilities, with an upper limit of the maximum total charging power.

4. 4. The power storage control device according to claim 3, wherein the time transition of the predicted value of the total surplus power of the plurality of facilities is derived based on a predicted value of the total power generation of the solar cell devices of the plurality of facilities for each of the plurality of unit periods that constitute the charging permission time slot, the predicted value being derived based on a predicted amount of solar radiation at each of the solar cell devices of the plurality of facilities for each of the plurality of unit periods that constitute the charging permission time slot, and a predicted value of the total load power of the power load of the plurality of facilities for each of the plurality of unit periods that constitute the charging permission time slot.

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