WO2015019387A1

WO2015019387A1 - Storage battery management device

Info

Publication number: WO2015019387A1
Application number: PCT/JP2013/004779
Authority: WO
Inventors: 靖弘大上; 洋輔大槻; 岩▲崎▼　利哉
Original assignee: 三洋電機株式会社
Priority date: 2013-08-07
Filing date: 2013-08-07
Publication date: 2015-02-12

Abstract

An upper limit capacity setting unit (132) sets, as an upper limit capacity of power with which a storage battery module is to be charged, a first upper limit capacity or a second upper limit capacity that is smaller than the first upper limit capacity. A user input receiving unit (33) acquires, from a user, an instruction of whether the upper limit capacity setting unit (132) is to set the first upper limit capacity or the second upper limit capacity. In the cases where the setting of the upper limit capacity is changed from the first upper limit capacity to the second upper limit capacity due to the instruction acquired by the user input receiving unit (33), a charge/discharge control unit (35) forcibly makes the storage battery module discharge electricity until the residual capacity of the storage battery module becomes equal to the second upper limit capacity when the residual capacity of the storage battery module is more than the second upper limit capacity.

Description

Battery management device

The present invention relates to a storage battery management device.

Recently, a system that links a photovoltaic power generation system to a power storage system connected to a system power supply has been developed. Since the storage battery is a direct current and the system power supply is an alternating current, an inverter is provided between them.

Japanese Examined Patent Publication No. 6-106021

Since the storage battery in such a system aims to assist the system power supply, it is preferable that as much power as possible can be discharged. On the other hand, since the storage battery is expensive, there is a demand for extending the life of the storage battery rather than discharging a lot of electric power.

The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for extending the life of a storage battery for assisting a system power supply.

In order to solve the above-described problem, a storage battery management device according to an aspect of the present invention provides either a first upper limit capacity or a second upper limit capacity that is less than the first upper limit capacity as the upper limit capacity of power to be charged in the storage battery. An upper limit capacity setting unit that sets the battery, a user input receiving unit that acquires an instruction from the user as to whether the upper limit capacity setting unit sets the first upper limit capacity or the second upper limit capacity, and manages charge / discharge of the storage battery A charge / discharge control unit. Here, the charge / discharge control unit changes the setting of the upper limit capacity from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input reception unit, and the remaining capacity of the storage battery is larger than the second upper limit capacity Forcibly discharges the storage battery until the remaining capacity of the storage battery reaches the second upper limit capacity.

According to the present invention, the life of the storage battery for assisting the system power supply can be extended.

It is a figure for demonstrating the electrical storage system which concerns on embodiment of this invention. It is a figure for demonstrating the grid connection mode of the electrical storage system which concerns on embodiment of this invention. It is a figure for demonstrating the self-sustained operation mode of the electrical storage system which concerns on embodiment of this invention. FIGS. 4A to 4D are diagrams for explaining a physical configuration example of the power storage system according to the embodiment of the present invention. It is the figure which looked at the housing | casing from the right side surface. It is a functional block diagram for demonstrating the component of the electrical storage system of FIG. It is a flowchart for demonstrating the control example of the 6th switch in self-sustained operation mode by the electrical storage system which concerns on embodiment of this invention. It is a flowchart for demonstrating the example of control of components other than the 6th switch in self-sustained operation mode by the electrical storage system which concerns on embodiment of this invention. It is a flowchart for demonstrating the communication space | interval switching process between a storage battery management apparatus and PV power conditioner in the electrical storage system which concerns on embodiment of this invention. It is a figure for demonstrating the electrical storage system which concerns on the 1st modification of this invention. It is a figure for demonstrating the storage battery management apparatus which concerns on the 2nd modification of this invention. It is a figure which shows an example of the time change of SOC of a storage battery module in the case of carrying out forced discharge by a constant current. It is a figure which shows an example of the time change of the voltage of a storage battery module in the case of carrying out forced discharge by a constant voltage. It is a figure which shows an example of the time change of the voltage of a storage battery module in the case of carrying out forced discharge combining the constant voltage discharge and the constant current discharge. It is a flowchart explaining the flow of the forced discharge process which concerns on the 2nd modification of this invention.

The embodiment of the present invention relates to a power storage system connected to a system power supply, and further relates to a power storage system linked to a solar power generation system. The power storage system is installed in, for example, industrial facilities, public facilities, commercial facilities, office buildings, residences, and the like. When the electric power company adopts the electricity bill system by time zone, the electricity bill at night time is set lower than the electricity bill at daytime. For example, the electricity charge from 23:00 to 7:00 on the next day is set cheaper than other time zones. Therefore, the electricity charge can be suppressed by charging the storage battery from the system power supply at night and using the electric power stored in the storage battery during the daytime. From the power company side, the amount of power used will be leveled.

The electric power stored in the storage battery is used as a backup power source for operating a specific load (for example, a light, an elevator, a computer server, etc.) when the system power supply fails. The specific load is a preset load that can receive power supply from the storage battery or the solar power generation system preferentially at the time of a power failure of the system power supply. In the present specification, other loads are referred to as general loads.

FIG. 1 is a diagram for explaining a power storage system 100 according to an embodiment of the present invention. The power storage system 100 according to the embodiment includes a storage battery module 10, a storage battery power conditioner 20, a storage battery management device 30, an inverter fan 50, a storage battery fan 60, a first switch S1 to a ninth switch S9, and a first breaker B1 to a third. A breaker B3 is provided. In the present embodiment, it is assumed that relays are used for the first switch S1 to the ninth switch S9. A semiconductor switch such as a power MOSFET may be used instead of the relay.

System power supply 200 is a commercial power supply supplied from an electric power company. The system power supply 200 is connected to the storage battery power conditioner 20 via the second switch S2. Moreover, it is connected to the PV power conditioner 40 through the fourth switch S4, the fifth switch S5, and the second breaker B2. Between the storage battery power conditioner 20 and the PV power conditioner 40, the second switch S2, the fourth switch S4, the fifth switch S5, the second breaker B2, or the third switch S3, the fourth switch S4, the fifth It is connected via the switch S5 and the second breaker B2.

The path between the grid power supply 200 and the storage battery power conditioner 20, the path between the grid power supply 200 and the PV power conditioner 40, and the path between the storage battery power conditioner 20 and the PV power conditioner 40 are configured to be conductive. Alternating current flows through these paths. Hereinafter, these paths are collectively referred to as an alternating current path.

The storage battery power conditioner 20 is connected to the storage battery module 10 via the first switch S1 and the first breaker B1. The photovoltaic power generation system 300 includes a solar cell 310 and a PV power conditioner 40, and the PV power conditioner 40 is connected to the solar cell 310.

The storage battery power conditioner 20 includes a bidirectional inverter 21 (see FIG. 6) as described later. The bidirectional inverter 21 converts AC power into DC power when charging the storage battery module 10, and converts DC power into AC power when discharging from the storage battery module 10. The PV power conditioner 40 includes an inverter 41 (see FIG. 6) as will be described later. The inverter 41 converts DC power generated by the solar power generation system 300 into AC power.

The storage battery module 10 is a packaged secondary battery that can be freely charged and discharged and can be used repeatedly. The storage battery module 10 includes a plurality of storage battery cells connected in series or series-parallel. In the present embodiment, it is assumed that a lithium ion battery is used as the storage battery cell. Other types of batteries such as nickel metal hydride batteries and lead batteries may be used instead of lithium ion batteries. One or a plurality of storage battery modules 10 are used in combination.

In this embodiment, it is assumed that six storage battery modules 10 are connected in series. The plurality of storage battery modules 10 connected in series are connected / disconnected by the switching unit. A plurality of storage battery modules 10 may be used in series-parallel connection. The storage battery module 10 is charged with grid power or power generated by the solar power generation system 300.

The solar power generation system 300 is a power generation device that uses the photovoltaic effect. Any of a silicon system, a compound system, and an organic system may be used for the solar battery constituting the solar power generation system 300.

The storage battery power conditioner 20 converts the DC power output from the storage battery module 10 into AC power, and the PV power conditioner 40 converts the DC power generated by the photovoltaic power generation system 300 into AC power. 200, the storage battery module 10, and the photovoltaic power generation system 300 can be linked by a single alternating current path.

General load 400 is connected on a path between system power supply 200 and power storage system 100. The specific load 500 is connected to a node between the fourth switch S4 and the fifth switch S5 in the AC current path via the sixth switch S6 and the third breaker B3.

General load 400 and specific load 500 operate by receiving AC power supplied from an AC current path. At the time of a power failure of the system power supply 200, the specific load 500 can receive power supply from at least one of the storage battery module 10 and the photovoltaic power generation system 300, but the general load 400 cannot receive power supply.

The inverter fan 50 is connected to a node between the fourth switch S4 and the fifth switch S5 in the AC current path via the seventh switch S7. The inverter fan 50 is a fan for cooling the bidirectional inverter 21 of the storage battery power conditioner 20.

The storage battery fan 60 is connected to a node between the fourth switch S4 and the fifth switch S5 in the AC current path via the ninth switch S9. The storage battery fan 60 is a fan that is operated when the storage battery module 10 is cooled and heated.

The heater 70 is connected to a node between the fourth switch S4 and the fifth switch S5 in the AC current path via the eighth switch S8. The heater 70 is a heater for heating the storage battery module 10 and is used for increasing the temperature of the storage battery cell in the storage battery module 10.

The temperature sensor 600 detects the outside air temperature as the environmental temperature and outputs it to the storage battery management device 30. For example, a thermistor can be used as the temperature sensor 600.

The storage battery management device 30 is mainly a device for managing the storage battery module 10. The storage battery management device 30 and the storage battery power conditioner 20 are connected to each other, and the storage battery management device 30 and the PV power conditioner 40 are connected to each other by a communication line using a metal wire. Between them, communication conforming to serial communication standards such as RS-232C and RS-485 is executed. The communication lines are insulated from each other by using optical fibers.

Further, the storage battery management device 30 is connected to the storage battery module 10 through a communication line using an optical fiber. In addition, the storage battery management device 30 is connected to each of the seventh switch S7 to the ninth switch S9 by a communication line using metal wiring. The storage battery management device 30 indirectly controls the inverter fan 50 and the like by controlling on / off of the seventh switch S7 to the ninth switch S9. Detailed operation of the storage battery management device 30 will be described later. Each of the first switch S1 to the sixth switch S6 and the first breaker B1 to the third breaker B3 is connected to the storage battery power conditioner 20 through a communication line using metal wiring. These are controlled by a control circuit 22 (see FIG. 6), which will be described later, in the storage battery power conditioner 20 based on an instruction from the storage battery management device 30 to the storage battery power conditioner 20 or based on a judgment unique to the storage battery power conditioner 20. .

The power storage system 100 according to the embodiment is operated in either the grid connection mode or the independent operation mode. The self-sustained operation mode is basically selected at the time of power failure of the system power supply 200.

FIG. 2 is a diagram for explaining a grid interconnection mode of power storage system 100 according to the embodiment of the present invention. In the grid connection mode, as shown in FIG. 2, the control circuit 22 in the storage battery power conditioner 20 controls the second switch S2 to be on, the third switch S3 to be off, and the fourth switch S4 to the third switch side. Control to connect to the terminal on the system power supply side instead. In the grid connection mode, the grid power supply 200, the photovoltaic power generation system 300, and the storage battery module 10 are conducted through a single AC current path AP (see thick line).

When discharging from the storage battery module 10 in the grid connection mode, the bidirectional inverter 21 of the storage battery power conditioner 20 causes a current to flow through the AC current path AP at a frequency and phase synchronized with the frequency of the system power supply 200.

FIG. 3 is a diagram for explaining a self-sustaining operation mode of power storage system 100 according to the embodiment of the present invention. In the self-sustaining operation mode, as shown in FIG. 3, the control circuit 22 in the storage battery power conditioner 20 controls the second switch S2 to be turned off and the third switch S3 to be turned on, and the fourth switch S4 is turned on the system power supply side. Control to connect to the terminal on the third switch side. In the self-sustaining operation mode, the photovoltaic power generation system 300 and the storage battery module 10 are electrically disconnected from the system power supply 200.

When discharging from the storage battery module 10 in the self-sustained operation mode, the bidirectional inverter 21 of the storage battery power conditioner 20 causes a current to flow from the system power supply 200 to the AC current path AP at a frequency and phase independent from each other. The specific load 500 is electrically connected to the alternating current path AP (see thick line) formed in the self-sustained operation mode, but the general load 400 is electrically cut off. Therefore, the power stored in the storage battery module 10 and the power generated by the solar power generation system 300 can be supplied only to the specific load 500 at the time of a power failure.

FIGS. 4A to 4D are diagrams for explaining a physical configuration example of the power storage system 100 according to the embodiment of the present invention. The components of the power storage system 100 surrounded by a dotted line in FIGS. 1 to 3 are housed in a housing 110 having an openable door. 4A is a view of the housing 110 viewed from the top surface 110t, FIG. 4B is a view of the housing 110 viewed from the front surface 110f, and FIG. 4C is a view of the housing 110 viewed from the bottom surface 110b. FIG. 4D is a view of the housing 110 viewed from the right side 110s.

The housing 110 is a vertically long box, and the storage battery module 10 is disposed in the lower part of the housing 110. In the present embodiment, six storage battery modules 10 are arranged side by side vertically. Although not shown, the storage battery management device 30 is disposed on the storage battery module 10, and the storage battery power conditioner 20, the first breaker B1 to the third breaker B3 are disposed thereon. Thus, the bidirectional inverter 21 of the storage battery power conditioner 20 is arranged on the top surface side from the storage battery module 10. The PV power conditioner 40 may also be designed to be installed in the housing 110.

As shown in FIG. 4A, a first air hole 111 is provided in the top surface 110t of the housing 110. An inverter fan 50 is provided in the vicinity of the first air hole 111. The inverter fan 50 is an exhaust fan and discharges hot air in the vicinity of the bidirectional inverter 21. The inverter fan 50 cools the bidirectional inverter 21 by sucking up air introduced from the second air hole 113 and the third air hole 114 provided in the lower part of the casing 110.

A storage battery fan 60 is provided in the lower part of the housing 110. The storage battery fan 60 introduces outside air from the second air hole 113 and the third air hole 114. By using the inverter fan 50 and the storage battery fan 60 in combination, the cooling efficiency of the storage battery module 10 can be increased. In addition, by taking in air from the lower part and exhausting from the upper part, it is possible to expect the effect that the temperature of the battery rises due to the discharge of the storage battery and that the waste heat of the inverter is sent to the upper part by the updraft.

As shown in FIG. 4B, a handle 112, a second air hole 113, and a third air hole 114 are provided on the front surface 110f of the housing 110. The second air hole 113 and the third air hole 114 are provided side by side below the front surface 110f. As shown in FIG. 4C, two

entry holes

115 and 116 are provided on the bottom surface 110 b of the housing 110.

FIG. 5 is a view of the housing 110 viewed from the right side surface 110s. FIG. 5 is a diagram depicting the vicinity of region A in FIG. 4D in more detail. The storage battery fan 60 is arranged in the vicinity of the bottom surface in the housing 110 so that the outside air inlet faces the second air hole 113 and the third air hole 114.

The heater 70 receives air sent from the storage battery fan 60 and sends warm air. In the present embodiment, the heater 70 includes a heat sink, and the storage battery fan 60 and the heater 70 are configured so that the air outlet of the storage battery fan 60 and the heat sink face each other. The storage battery fan 60 and the heater 70 are provided on the bottom side of the storage battery module 10. When the storage battery module 10 is heated, both the storage battery fan 60 and the heater 70 are operated to warm and release the air sucked from the second air hole 113 and the third air hole 114. As shown in FIG. 4D, the discharged warm air rises from the bottom surface side to the top surface side in the housing 110 and is exhausted from the first air hole 111 provided on the top surface.

FIG. 6 is a functional block diagram for explaining the components of the power storage system 100 of FIG. The storage battery module 10 includes a storage battery cell 11, a voltage sensor 12, a current sensor 13, and a temperature sensor 14. The storage battery cell 11 of FIG. 6 is drawn as a general term for a plurality of storage battery cells.

The voltage sensor 12 detects the voltage of each storage battery cell. The current sensor 13 detects the current flowing through the storage battery cell 11. A Hall element or a shunt resistor can be used for the current sensor 13. The temperature sensor 14 detects the temperature of the storage battery cell 11 in the storage battery module 10. A thermistor can be used for the temperature sensor 14. The voltage value detected by the voltage sensor 12, the current value detected by the current sensor 13, and the temperature value detected by the temperature sensor 14 are output as monitoring data of the storage battery module 10 to the storage battery management device 30 via the communication path. The

The storage battery power conditioner 20 includes a bidirectional inverter 21 and a control circuit 22. The control circuit 22 executes mode management of the power storage system 100, control of the bidirectional inverter 21, communication with the storage battery management device 30, control of the first switch S1 to sixth switch S6, control of the first breaker B1 to third breaker B3, and the like. To do. The control circuit 22 controls the inverter fan 50 in order to cool the bidirectional inverter 21.

The PV power conditioner 40 includes an inverter 41 and a control circuit 42. The control circuit 42 executes state management of the photovoltaic power generation system 300, power generation control, communication with the storage battery management device 30, and the like. The display device 700 displays various setting screens, status information of the storage battery module 10 and the photovoltaic power generation system 300 under the control of the storage battery management device 30.

The storage battery management device 30 includes a communication unit 31, a monitoring data acquisition unit 32, a user input reception unit 33, an SOC (StategeOf Charge) calculation unit 34, a charge / discharge control unit 35, a power generation control unit 36, a temperature control unit 37, a fan / heater A control unit 38 and a switch control unit 39 are provided. These configurations can be realized by an arbitrary processor, memory, or other LSI in terms of hardware, and are realized by a program loaded in the memory in terms of software. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

The communication unit 31 controls packet communication between the storage battery management device 30 and the storage battery power conditioner 20, and packet communication between the storage battery management device 30 and the PV power conditioner 40. The monitoring data acquisition unit 32 acquires monitoring data transmitted from the storage battery module 10. In addition, the monitoring data acquisition unit 32 acquires temperature data indicating the temperature outside the housing 110 transmitted from the temperature sensor 600.

The user input reception unit 33 receives information input to the operation unit 800 by the user. For example, information such as a charging start time at which charging processing from the system power supply 200 to the storage battery module 10 is started and a charging rate thereof is received.

The SOC calculation unit 34 calculates the SOC (remaining capacity) of the storage battery cell 11 based on the monitoring data transmitted from the storage battery module 10. As an SOC calculation method, an OCV (Open Circuit Voltage) method or a Coulomb count method can be used.

The charge / discharge control unit 35 transmits to the control circuit 22 of the storage battery power conditioner 20 a packet signal including a charge setting value indicating a charge rate when the storage battery module 10 is charged. In addition, the charge / discharge control unit 35 transmits a packet signal including a discharge set value indicating a discharge rate when discharging from the storage battery module 10 to the control circuit 22. Further, the charge / discharge control unit 35 receives a packet signal including a charge value that is actually charged or a discharge value that is actually discharged from the control circuit 22. While the storage battery module 10 is being charged or discharged, the charge / discharge control unit 35 periodically transmits a packet signal to the control circuit 22 (for example, every 1 second). Each time the control circuit 22 receives the packet signal, it returns a packet signal containing actual data.

The power generation control unit 36 receives a packet signal including power generation information of the solar power generation system 300 from the control circuit 42 of the PV power conditioner 40. The power generation control unit 36 transmits a packet signal including information for controlling power generation to the control circuit 42. The power generation control unit 36 transmits the packet signal to the control circuit 42 periodically (for example, every 1 second). Each time the control circuit 42 receives the packet signal, it returns a packet signal containing actual data. When there is no response from the control circuit 42, the power generation control unit 36 lengthens the transmission cycle of the packet signal. For example, the period is changed to one minute.

The temperature control unit 37 controls the temperature of the storage battery cell 11 and controls the fan / heater control unit 38 to adjust the temperature of the storage battery cell 11. When cooling the storage battery cell 11, the fan / heater control unit 38 operates at least one of the storage battery fan 60 and the inverter fan 50. Basically, the storage battery fan 60 is operated, and the outside air sucked from the second air hole 113 and the third air hole 114 is blown to the storage battery cell 11 to cool the storage battery cell 11. At that time, when the inverter fan 50 is operated, introduction of outside air can be promoted. When the inverter fan 50 is an intake fan, the inverter fan 50 can be operated to introduce outside air from the upper side of the storage battery cell 11.

When the storage battery cell 11 is heated, the fan / heater control unit 38 operates the storage battery fan 60 and the heater 70 and controls the inverter fan 50 to be inactive. As shown in FIG. 4D, the hot air blows up from the lower part of the storage battery module 10 to the upper part, whereby the temperature of the storage battery cell 11 can be increased. At this time, by stopping the inverter fan 50, introduction of outside air from the second air hole 113 and the third air hole 114 can be suppressed, and the air heated by the heater 70 can be circulated inside the housing 110. . Thereby, the heating efficiency of the heater 70 is improved. In addition, when the inverter fan 50 is an intake fan, it can prevent that external air is blown from the upper part side of the storage battery module 10 by stopping the inverter fan 50. FIG. The situation in which the storage battery cell 11 needs to be heated is usually a state in which the outside air temperature is low. When the inverter fan 50 is operated, cold air is blown onto the storage battery module 10 from above.

The switch control unit 39 transmits a packet signal including control information to the control circuit 22 of the storage battery power conditioner 20, and through the control circuit 22, the first switch S1 to the sixth switch S6 and the first breaker B1 to the first breaker B1. The control of the 3 breaker B3 can be performed. The switch control unit 39 can stop the power supply to the heater 70 by controlling the eighth switch S8 to be off. In addition, the power supply to the storage battery fan 60 can be stopped by controlling the ninth switch S9 to be off. Further, the power supply to the inverter fan 50 can be stopped by controlling the seventh switch S7 to be turned off. The seventh switch S7, the eighth switch S8, and the ninth switch S9 can also be controlled from the control circuit 22 of the storage battery power conditioner 20.

The switch control unit 39 can stop the power supply to the specific load 500 by controlling the sixth switch S6 to be off. The switch control unit 39 turns off the sixth switch S6 when the power consumption of the specific load 500 exceeds the generated power of the solar power generation system 300 at the time of a power failure of the system power supply 200. When the sixth switch S6 is turned off under this condition, there is a tendency that the power supply opportunity to the specific load 500 at the time of a power failure decreases. In particular, when a power failure occurs at night, the specific load 500 cannot be supplied with power. Therefore, when the power consumption of the specific load 500 exceeds a certain power, the sixth switch S6 may be controlled based on the above-described conditions. That is, when the power consumption of the specific load 500 is less than or equal to a certain power, the power supply to the specific load 500 is not stopped. If the constant power is 1 kW, for example, the specific load 500 can be used within a range not exceeding 1 kW regardless of the power generation of the solar power generation system 300. Therefore, the power supply opportunity to the specific load 500 at the time of a power failure can be increased. Here, it is desirable to determine the value of the constant power in consideration of the power consumption of lighting and air conditioning equipment that is assumed to be used during a power failure.

In addition, the switch control unit 39 is the first when the power consumption of the specific load 500 exceeds the adjusted generated power obtained by adding the adjusted power (positive value) to the generated power of the photovoltaic power generation system 300 during the power failure of the system power supply 200. The 6 switch S6 may be turned off. Also in this case, the power supply opportunity to the specific load 500 at the time of a power failure can be increased. Here, it is desirable to determine the value of the adjusted power in consideration of securing a power supply opportunity to the specific load 500 and protecting the storage battery.

Further, the switch control unit 39 turns off the sixth switch S6 when the SOC of the storage battery module 10 falls below a set value for preventing overdischarge (for example, 10%) during a power failure of the system power supply 200. The overdischarge prevention set value is set according to the capacity of the specific load 500. As the capacity of the specific load 500 is smaller, a smaller value is set as the overdischarge prevention set value. The switch control unit 39 may turn off the sixth switch S6 when both of the two conditions are satisfied, or may turn off the sixth switch S6 only when one of the two conditions is satisfied.

The power storage system 100 operates in the self-sustaining operation mode at the time of power failure of the system power supply 200. Therefore, when the power consumption of the specific load 500 exceeds the power generation power of the solar power generation system 300, the capacity of the storage battery module 10 decreases. The storage battery module 10 deteriorates when overdischarged.

When importance is attached to the protection of the storage battery module 10, power supply to the specific load 500 is stopped when the power consumption of the specific load 500 exceeds the generated power of the solar power generation system 300 regardless of the SOC value. In addition, when emphasizing the maintenance of power supply to the specific load 500, when the SOC of the storage battery module 10 is below the set value for preventing overdischarge and the power consumption of the specific load 500 exceeds the power generation of the solar power generation system 300 Power supply to the specific load 500 is stopped. When the generated power of the solar power generation system 300 exceeds the power consumption of the specific load 500, the sixth switch S6 is not turned off because the SOC of the storage battery module 10 is in a recovery direction.

Whether or not the power consumption of the specific load 500 exceeds the power generation of the solar power generation system 300 can be determined by detecting whether or not the power storage system 100 is discharged. In the self-sustaining operation mode, when the power consumption of the specific load 500 exceeds the power generation power of the solar power generation system 300, the storage battery module 10 is in a discharged state. Conversely, when the power consumption of the specific load 500 is lower than the power generation of the solar power generation system 300, the storage battery module 10 is in a charged state. The switch control unit 39 can specify whether the storage battery module 10 is discharging or charging with reference to information included in the packet signal received from the control circuit 22 of the storage battery power conditioner 20.

Alternatively, a current sensor may be installed in the AC current path, and it may be determined whether or not the power consumption of the specific load 500 exceeds the generated power of the photovoltaic power generation system 300 from the direction of the current. Further, a current sensor may be installed in the current path between the AC current path and the specific load 500, and the determination may be made based on the measured value.

FIG. 7 is a flowchart for explaining a control example of the sixth switch S6 in the self-sustaining operation mode by the power storage system 100 according to the embodiment of the present invention. The monitoring data acquisition part 32 acquires monitoring data, such as a voltage value of a storage battery cell, from the storage battery module 10 (S10). The SOC calculation unit 34 calculates the SOC of the storage battery module 10 based on the monitoring data (S11). The switch control unit 39 compares the calculated SOC with the first set value for preventing overdischarge (S12). When the SOC is equal to or higher than the first set value (N in S12), the process proceeds to step S10. When the SOC is less than the first set value (Y in S12), the switch control unit 39 determines whether or not the storage battery module 10 is in a discharged state (S13). When not in the discharging state (N in S13), the process proceeds to step S10. When it is in a discharging state (Y in S13), the switch control unit 39 turns off the sixth switch S6 (S14).

The monitoring data acquisition part 32 acquires monitoring data, such as a voltage value of a storage battery cell, from the storage battery module 10 (S15). The SOC calculation unit 34 calculates the SOC of the storage battery module 10 based on the monitoring data (S16). The switch control unit 39 compares the calculated SOC with the second set value for return (S17). The second set value is set to a value larger than the first set value. For example, the first set value + 10% is set.

When the SOC is equal to or greater than the second set value (N in S17), the process proceeds to step S15. When the SOC is less than the second set value (Y in S17), the switch control unit 39 turns on the sixth switch S6 (S18). The additional condition may be that the storage battery module 10 is in a discharged state. An additional condition may be that the display device 700 displays that the return is possible and the user inputs a return instruction to the operation unit 800. In this case, when the SOC of the storage battery module 10 becomes equal to or higher than the second set value after the sixth switch S6 is turned off, the switch control unit 39 causes the display device 700 to display that it can be returned. When the specific load 500 includes a heat dissipating device such as an electric heater, the heat dissipating device stops when the sixth switch S6 is turned off. is there. By making the user operation a condition, the user can be made aware of the resumption of power supply.

The load to be the specific load 500 is selected by the user. Therefore, for example, in the case of only the specific load 500 that does not become an unsafe state even if the LED light is automatically restored, it is not necessary to make a user operation a condition. The user can set in advance whether or not to automatically return from the setting screen displayed on the display device 700 before the start of operation. When this setting is valid, when the SOC becomes equal to or higher than the second set value, the switch control unit 39 turns on the sixth switch S6 and automatically restarts power supply. Note that even if the automatic / manual return setting is changed during operation, it will not be reflected unless the system operation is stopped and restarted.

The processing from step S10 to step S18 is executed until the self-sustained operation of the power storage system 100 ends (Y in S19) (N in S19). Although shown at the bottom in FIG. 7 for the sake of convenience, the operation end determination process is executed at any time.

FIG. 8 is a flowchart for explaining a control example of components other than the sixth switch S6 in the self-sustaining operation mode by the power storage system 100 according to the embodiment of the present invention. The monitoring data acquisition part 32 acquires monitoring data, such as a voltage value of a storage battery cell, from the storage battery module 10 (S20). The SOC calculation unit 34 calculates the SOC of the storage battery module 10 based on the monitoring data (S21). The power generation control unit 36 acquires the power generation information of the solar power generation system 300 from the control circuit 42 of the PV power conditioner 40 (S22).

The switch control unit 39 compares the calculated SOC with the first set value for preventing overdischarge (S23). When the SOC is greater than or equal to the first set value (N in S23), the process proceeds to step S20. When the SOC is less than the first set value (Y in S23), the power generation control unit 36 determines whether or not the solar power generation system 300 is generating power (S24). In the power generation state (N in S24), the process proceeds to step S20. In the non-power generation state (Y in S24), the fan / heater control unit 38 controls the heater 70 to be inactive (S25). When the heater 70 is operating, it is stopped, and when it is not operating, the state is maintained. The fan / heater control unit 38 may also control the storage battery fan 60 and the inverter fan 50 to be inactive.

If the SOC is less than the first set value, the battery module 10 is not discharged, and the battery module 10 is not charged when the photovoltaic power generation system 300 is not generating power. Therefore, there is no need to heat the storage battery module 10. By controlling the heater 70 to be inactive, the power consumption of the heater 70 can be reduced. In the self-sustained operation mode at the time of a power failure, the heater 70 cannot be operated when the power supply from the storage battery module 10 and the photovoltaic power generation system 300 is stopped. The process of step S25 mainly assumes a situation where power can be secured from other than the storage battery module 10 and the solar power generation system 300.

The power generation control unit 36 causes the PV power conditioner 40 to shift to the sleep mode by including an instruction to shift to the sleep mode in the packet signal transmitted to the PV power conditioner 40 (S26). Thereby, the power consumption of the PV power conditioner 40 can be reduced. In addition, after the electric power generation of the solar power generation system 300 stops, the control circuit 42 of the PV power conditioner 40 may shift the PV power conditioner 40 to the sleep mode by self-determination.

The charging / discharging control unit 35 causes the storage battery power conditioner 20 to shift to the sleep mode by including an instruction to shift to the sleep mode in the packet signal transmitted to the storage battery power conditioner 20 (S27). Since the discharge from the storage battery module 10 is prohibited and neither the grid power supply 200 nor the solar power generation system 300 is charged, the storage battery power conditioner 20 is caused to sleep. Thereby, the power consumption of the storage battery power conditioner 20 can be reduced.

When the photovoltaic power generation system 300 resumes power generation (Y in S28), the control circuit 42 of the PV power conditioner 40 returns the PV power conditioner 40 from the sleep mode to the normal mode (S29). When the charge / discharge control unit 35 detects the resumption of power generation of the photovoltaic power generation system 300 with reference to the packet signal received from the PV power conditioner 40, the charge / discharge control unit 35 returns the storage battery power conditioner 20 from the sleep mode to the normal mode (S30). .

The process from step S20 to step S30 is executed until the self-sustained operation of the power storage system 100 ends (Y in S31) (N in S31). In FIG. 8, for the sake of convenience, it is drawn at the bottom, but the determination process for the end of operation is executed at any time.

FIG. 9 is a flowchart for explaining a communication interval switching process between the storage battery management device 30 and the PV power conditioner 40 in the power storage system 100 according to the embodiment of the present invention. When the PV power conditioner 40 is in the sleep mode (Y in S35), the communication unit 31 of the storage battery management device 30 decreases the communication frequency between the storage battery management device 30 and the PV power conditioner 40 (S36). That is, the communication interval is lengthened. At night, the PV power conditioner 40 is normally in the sleep mode, so the communication interval becomes longer. When the PV power conditioner 40 is in the normal mode (N in S35), the communication unit 31 of the storage battery management device 30 sets the communication frequency between the storage battery management device 30 and the PV power conditioner 40 to normal (S37). Until the operation of the power storage system 100 ends (Y in S38), the processing from step S35 to step S37 is repeatedly executed (N in S38).

As described above, according to the present embodiment, when the solar power generation system 300 is linked to the power storage system 100 connected to the system power supply, the solar power generation system 300 is connected to the power storage system 100 via the PV power conditioner 40. Connect to. That is, it connects with the storage battery module 10 and the system power supply 200 with an alternating current output.

It is conceivable to connect the photovoltaic power generation system 300 to the direct current side of the storage battery power conditioner 20, but in this case, the output range of the photovoltaic power generation system 300 needs to be within the rated range of the storage battery power conditioner 20. is there. When the photovoltaic power generation system 300 is added to the existing power storage system 100, it is necessary to select the photovoltaic power generation system 300 that falls within the rated range of the storage battery power conditioner 20. Further, it may be impossible to link the existing power storage system 100 to the existing solar power generation system 300.

When the solar power generation system 300 is connected to the direct current side of the storage battery power conditioner 20, it is conceivable to install a DC-DC converter between the solar power generation system 300 and the storage battery power conditioner 20. In this case, the cost for installing the DC-DC converter increases, and conversion loss occurs not only in the storage battery power conditioner 20 but also in the DC-DC converter, so that the energy efficiency is lowered.

On the other hand, according to the present embodiment, by providing the PV power conditioner 40, various types of photovoltaic power generation systems 300 can be connected to the power storage system 100 without limitation of the output range. In addition, since a DC-DC converter is unnecessary, it is possible to avoid a reduction in energy efficiency.

In addition, when the power consumption of the specific load 500 exceeds the generated power of the photovoltaic power generation system 300 and / or when the SOC of the storage battery module 10 falls below the first set value in the self-sustained operation mode, power supply to the specific load 500 is stopped. . Thereby, the overdischarge of the storage battery module 10 can be prevented, and the storage battery module 10 can be protected.

The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. is there.

[First Modification]
FIG. 10 is a diagram for explaining a power storage system 100 according to a first modification of the present invention. The power storage system 100 according to the first modification has a configuration in which the fifth switch S5 and the sixth switch S6 of the power storage system 100 illustrated in FIG. 1-3 are omitted.

In the power storage system 100 shown in FIG. 1-3, the sixth switch S6 connected in series with the third breaker B3 is used as an element for cutting off the power supply to the specific load 500. In this configuration, after the sixth switch S6 is turned off (open in the case of a relay) as described above, it is turned on (closed in the case of a relay) when the SOC of the storage battery module 10 exceeds the second set value for return, It can be automatically restored.

In the first modification, the switch control unit 39 closes the third breaker B3 when stopping the power supply to the specific load 500. The third breaker B3 has a coil and a contact, and the coil is excited with overcurrent detection as a trigger to close the contact. The third breaker B3 has another coil that is energized by external control. The switch control unit 39 can close the contact by controlling the current to flow through the other coil.

Thus, according to the first modification, since the fifth switch S5 and the sixth switch S6 are omitted, the cost of the entire power storage system 100 can be reduced. The breaker must be manually reset once it is opened. That is, when the breaker trips, the breaker needs to be restarted. When the SOC of the storage battery module 10 exceeds the set value for return after opening the breaker, the switch control unit 39 displays on the display device 700 that the breaker can be returned. As described above, when the breaker is used for the sixth switch S6, the user's confirmation work is always required at the time of return, and the safety at the time of return can be further secured. The sixth switch S6 may be a reset switch. In this case, the sixth switch S6 is turned on by pressing the reset switch.

[Second Modification]
As described above, the electric power stored in the storage battery module 10 is used for so-called peak cut for leveling the amount of electric power used by daytime, or used as a backup power source when the system power source 200 is out of power. Or Thus, the storage battery module 10 is used to assist the system power supply 200 that is a commercial power supply. Here, when the electric power stored in the storage battery module 10 is used as a backup power supply when the system power supply 200 fails, the power of the storage battery module 10 is discharged when the system power supply 200 fails. On the other hand, when the electric power stored in the storage battery module 10 is used for peak cut, the storage battery module 10 is discharged even if the system power supply 200 is not interrupted.

The storage battery module 10 is a packaged secondary battery. The storage battery module 10 which concerns on a 2nd modification also assumes using a lithium ion battery as a storage battery cell. Of course, the larger the charging capacity for charging the storage battery module 10, the larger the amount of electric power that can be discharged at the time of peak cut or power failure of the system power supply 200. However, it is generally known that a lithium ion battery is deteriorated in performance and shortened in life when a fully charged state in which the charging capacity is allowed to the limit of the allowable range or a state close thereto is continued. For this reason, some users of the power storage system 100 give priority to extending the life of the storage battery module 10 rather than allowing the storage battery module 10 to discharge a large capacity.

Therefore, the power storage system 100 according to the modification includes two operation modes of a capacity priority mode and a life priority mode as operation modes of the storage battery module 10. Here, the “capacity priority mode” is a mode in which priority is given to increasing the amount of power charged in the storage battery module 10 so that the storage battery module 10 can discharge a large capacity. On the other hand, the “life priority mode” is a mode in which priority is given to extending the life of the storage battery module 10 rather than the storage battery module 10 discharging a large amount of power. These operation modes of the storage battery module 10 are managed by the storage battery management device 130 according to the modification.

FIG. 11 is a diagram for explaining a storage battery management device 130 according to a second modification of the present invention. The storage battery management device 130 according to the second modification is used in place of the storage battery management device 30 in the power storage system 100 shown in FIG. For this reason, the power storage system 100 according to the second modified example has the same configuration as the power storage system 100 according to the above-described embodiment, except for the storage battery management device 130. Therefore, the description overlapping with the power storage system 100 according to the embodiment is omitted or simplified below.

Similar to the storage battery management device 30 according to the embodiment, the storage battery management device 130 includes a communication unit 31, a monitoring data acquisition unit 32, a user input reception unit 33, an SOC calculation unit 34, a charge / discharge control unit 35, and a power generation control unit 36. A temperature control unit 37, a fan / heater control unit 38, and a switch control unit 39. The storage battery management device 130 further includes an upper limit capacity setting unit 132 and a use setting storage unit 134 in order to manage the operation mode of the storage battery module 10 described above.

The upper limit capacity setting unit 132 sets either the first upper limit capacity in the capacity priority mode or the second upper limit capacity in the life priority mode as the upper limit capacity of the electric power charged in the storage battery module 10. Here, since the second upper limit capacity is the upper limit capacity of the life priority mode, the second upper limit capacity is smaller than the first upper limit capacity which is the upper limit capacity of the capacity priority mode. The specific set values of the first upper limit capacity and the second upper limit capacity may be determined by experiments in consideration of the capacity and performance of the storage battery module 10, but as an example, the first upper limit capacity is determined by the storage battery module 10. 100% of the chargeable capacity, and the second upper limit capacity is 85% of the chargeable capacity of the storage battery module 10.

The user input reception unit 33 acquires from the user via the operation unit 800 whether the upper limit capacity setting unit 132 sets the first upper limit capacity or the second upper limit capacity. More specifically, the user input receiving unit 33 acquires an instruction from the user as to whether the operation mode of the storage battery module 10 is set to the capacity priority mode or the life priority mode.

For example, it is assumed that the user input receiving unit 33 acquires an instruction to change the operation mode of the storage battery module 10 from the capacity priority mode to the life priority mode. The monitoring data acquisition unit 32 acquires monitoring data such as the voltage value of the storage battery cell from the storage battery module 10 when the user input reception unit 33 acquires an instruction to change the operation mode of the storage battery module 10. Subsequently, the SOC calculation unit 34 calculates the SOC of the storage battery module 10 based on the monitoring data.

When the SOC of the storage battery module 10 calculated by the SOC calculation unit 34 is greater than the second upper limit capacity, the charge / discharge control unit 35 forces the storage battery module 10 until the SOC of the storage battery module 10 reaches the second upper limit capacity. To discharge.

Here, “forcibly discharging the storage battery module 10 (hereinafter, simply referred to as“ forced discharge ”)” does not reduce the remaining capacity of the storage battery module 10 by natural discharge, but actively discharges the storage battery module 10. That means. For example, the charge / discharge control unit 35 supplies power to the general load 400 or the specific load 500 until the SOC of the storage battery module 10 reaches the second upper limit capacity. Alternatively, when there is no demand for power in the general load 400 or the specific load 500, the charge / discharge control unit 35 may flow the power of the storage battery module 10 to the system power source 200.

By the way, as described above, when the power stored in the storage battery module 10 is used as a backup power supply when the system power supply 200 fails, the power of the storage battery module 10 is discharged when the system power supply 200 fails. On the other hand, when the electric power stored in the storage battery module 10 is used for peak cut, the storage battery module 10 is discharged even when the system power supply 200 is not out of power. For this reason, the power storage system 100 according to the second modified example is set to be used at the time of a power failure for discharging the storage battery module 10 when the system power source 200 fails, or is discharged even when the power of the system power source 200 is supplied. Either the use setting during energization to be performed can be selected freely.

In order to realize this, the user input reception unit 33 uses the storage battery module 10 even when the power supply for the power supply 200 is supplied and the power setting for discharging the storage battery module 10 when the power supply 200 is interrupted. Which setting to use when energized to be discharged is acquired from the user via the operation unit 800. The usage setting storage unit 134 stores the usage setting of the storage battery module 10 acquired by the user input reception unit 33.

Now, it is assumed that the storage battery module 10 is set to be used when energized according to the instruction acquired by the user input receiving unit 33. At this time, when the charge / discharge control unit 35 changes the setting of the upper limit capacity from the first upper limit capacity to the second upper limit capacity in accordance with the instruction acquired by the user input receiving unit 33, the remaining capacity of the storage battery module 10 is the second upper limit. When the capacity is larger than the capacity, the storage battery module 10 is forcibly discharged until the remaining capacity of the storage battery module reaches the second upper limit capacity. Since the storage battery module 10 is set to be used when energized, the charge / discharge control unit 35 can forcibly discharge the storage battery module 10 even when the system power supply 200 is not in a power failure.

On the other hand, it is assumed that the storage battery module 10 is set to be used during a power failure according to an instruction acquired by the user input receiving unit 33. At this time, when the setting of the upper limit capacity is changed from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input receiving unit 33, a case where the remaining capacity of the storage battery module 10 is larger than the second upper limit capacity is considered. . In this case, if priority is given to the use setting of the storage battery module 10, the charge / discharge control unit 35 cannot perform the discharge of the storage battery module 10 unless the system power supply 200 is in a power failure.

Therefore, the charge / discharge control unit 35 according to the second modified example prioritizes the change of the operation mode of the storage battery module 10 even when the storage battery module 10 is set to be used during a power failure. The storage battery module 10 is forcibly discharged until the remaining capacity reaches the second upper limit capacity. As a result, the remaining capacity of the storage battery module 10 can be set to the second upper limit capacity, and the intention of the user who wishes to extend the life of the storage battery module 10 can be reflected.

In addition, the storage battery module 10 has a capacity secured during a power failure that is secured to supply a specific load when the system power supply 200 is powered down, regardless of whether it is set for use during a power failure or for use during energization. The specific value of the capacity secured during a power failure may be determined in consideration of the type of specific load assumed by the power storage system 100, power consumption, and the like, but is 5 kwh as an example. The user of the power storage system 100 can also change the value of the reserved capacity at the time of power failure by inputting the user input reception unit 33 via the operation unit 800. The amount of difference between the remaining capacity of the storage battery module 10 and the capacity secured at the time of power failure is electric power that can be used as a peak cut.

Next, forced discharge performed by the charge / discharge control unit 35 according to the second modification will be described.

FIG. 12 is a diagram showing an example of the time change of the SOC of the storage battery module 10 when forced discharge is performed at a constant current. In the graph shown in FIG. 12, the horizontal axis represents time, the left vertical axis represents the SOC of the storage battery module 10, and the right vertical axis represents current or power during forced discharge. FIG. 12 shows that the user has changed the setting of the upper limit capacity of the storage battery module 10 from the first upper limit capacity to the second upper limit capacity at time T1. The SOC of the storage battery module 10 at time T1 is greater than the second upper limit capacity.

The charge / discharge control unit 35 starts forced discharge of the storage battery module 10 with a constant current at time T1. In Figure 12, the charging and discharging control unit 35 indicates that the forced discharge accumulator module 10 with a constant current I _C. Due to the forced discharge of the battery module 10 with a constant current I _C, SOC of the battery module 10 decreases with time, it reaches the second upper capacitor at time T2.

FIG. 13 is a diagram showing an example of a change over time of the voltage of the storage battery module 10 when forced discharge is performed at a constant voltage. In the graph shown in FIG. 13, the horizontal axis represents time, the left vertical axis represents the voltage of the storage battery module 10, and the right vertical axis represents the current or power during forced discharge. As in the case shown in FIG. 12, FIG. 13 also shows that the user has changed the setting of the upper limit capacity of the storage battery module 10 from the first upper limit capacity to the second upper limit capacity at time T1.

The release voltage V _t of the storage battery module 10 when the storage battery module 10 has the second upper limit capacity can be measured in advance by experiments. Therefore the charge and discharge control unit 35, as the voltage of the battery module 10 is released voltage V _t corresponding to the second upper capacitor, starts a forced discharge at a constant voltage at time T1.

If discharging is continued while maintaining the voltage at the time of discharging of the storage battery module 10, the amount of discharged current also decreases as the SOC of the storage battery module 10 decreases. Therefore, at time T3, the charge / discharge control unit 35 lowers the voltage at the time of discharging the storage battery module 10 to V2, which is lower than V1 by a predetermined voltage. As a result, the amount of discharged electric current temporarily increases, but eventually decreases for the same reason. At time T4 after time T3, the charge / discharge control unit 35 decreases the voltage at the time of discharging the storage battery module 10 to V3, which is lower than V2 by a predetermined voltage, thereby increasing the amount of current to be discharged. In this way, by maintaining the voltage at the time of discharge and decreasing the voltage at the time of discharge so as to increase the amount of current to be discharged, the release voltage V _t corresponding to the second upper limit capacity to be targeted. It is possible to speed up the time to reach.

Note that the amount of reduction when the voltage during discharge is lowered stepwise is determined by experiments in consideration of the characteristics of the storage battery module 10 and the limitations of the power storage system 100. For example, when the limit current I _r that is the upper limit of the current that the storage battery module 10 flows (or the limit voltage P _r that is the limit value of the power output from the storage battery module 10) is determined, it increases when the voltage is lowered. the amount of current is determined widths lowered such that lower than the limit current I _r. Thus, it is possible within the constraints of the battery module 10, to achieve a reduction in the time to reach the voltage V _t corresponding to the second upper limit capacity to be targeted.

Returning to the description of FIG. In time T5, the charging and discharging control unit 35 starts the discharge as a voltage V _t corresponding to the voltage during discharging of the battery module 10 to the second upper limit capacity. Here, since the charging / discharging control unit 35 controls the voltage at the time of discharging of the storage battery module 10 to be constant, the determination as to whether or not the SOC of the storage battery module 10 has actually reached the second upper limit capacity is discharged. The current value is determined.

The discharge end current I _e (or the discharge end power P _e ), which is the amount of current of the storage battery module 10 when the storage battery module 10 has the second upper limit capacity, can be measured in advance by experiments. Therefore, when the current value of the storage battery module 10 acquired from the monitoring data acquisition unit 32 becomes the discharge end current _Ie , the charge / discharge control unit 35 ends the discharge of the storage battery module 10.

In general, a voltage measured during or immediately after discharging the storage battery module 10 is different from a voltage measured after a predetermined time (for example, 10 minutes) has elapsed. More specifically, the voltage measured during or immediately after the discharge of the storage battery module 10 generally tends to be lower than a stable voltage after a predetermined time has elapsed. Therefore, the voltage V _t corresponding to the second upper limit capacity to be the target described above is higher than the release voltage V _t of the storage battery module 10 when the SOC of the storage battery module 10 is the second upper limit capacity in view of the above tendency. It is preferable to set to a low value V _t ′. Similarly, the discharge end current I _e is also preferably set to I _e ′, which is a current value when the release voltage of the storage battery module 10 is V _t ′. Thereby, the precision at the time of making SOC of the storage battery module 10 into a 2nd upper limit capacity | capacitance can be improved by discharging the storage battery module 10. FIG.

Heretofore, constant current discharge and constant voltage discharge have been described as modes of forced discharge of the storage battery module 10 by the charge / discharge control unit 35. In general, the constant current discharge can reduce the SOC of the storage battery module 10 faster than the constant voltage discharge. Meanwhile, the constant-voltage discharge as compared with the constant current discharge, a high accuracy in release voltage to target voltage of the battery module 10 is to V _t. Therefore, the charge / discharge control unit 35 may forcibly discharge the storage battery module 10 by combining constant voltage discharge and constant current discharge.

FIG. 14 is a diagram showing an example of a change over time of the voltage of the storage battery module 10 when forced discharge is performed by combining constant voltage discharge and constant current discharge. In the graph shown in FIG. 14, the horizontal axis represents time, the left vertical axis represents the voltage of the storage battery module 10, and the right vertical axis represents the current or power during forced discharge. Similarly to the case shown in FIGS. 12 and 13, FIG. 14 also shows that the user has changed the setting of the upper limit capacity of storage battery module 10 from the first upper limit capacity to the second upper limit capacity at time T <b> 1.

The charge / discharge control unit 35 starts constant current discharge at time T1. As a result, at time T7, the voltage of the battery module 10 has a voltage V _t corresponding to the second upper limit capacity. After time T7, the charge / discharge control unit 35 switches the forced discharge of the storage battery module 10 to constant voltage discharge. As a result, at time T8, the current value of the storage battery module 10 becomes the discharge end current _Ie .

In this way, first, the storage battery module 10 is discharged at a constant current, so that the SOC of the storage battery module 10 is quickly brought close to the vicinity of the second upper limit capacity, and thereafter, the SOC of the storage battery module 10 is switched to high-accuracy constant voltage discharge. The accuracy of SOC control in the storage battery module 10 can be increased while shortening the time required for forcibly discharging the battery until it reaches the second upper limit capacity.

Even when forced discharge is performed by combining constant voltage discharge and constant current discharge, it is preferable to employ V _t ′ as the voltage corresponding to the second upper limit capacity and I _e ′ as the discharge end current.

FIG. 15 is a flowchart illustrating the flow of forced discharge processing according to the second modification of the present invention.

The user input receiving unit 33 acquires a setting change of the upper limit capacity of the storage battery module 10 from the user via the operation unit 800 (S40). When the upper limit capacity of the storage battery module 10 is changed from the first upper limit capacity to the second upper limit capacity (Y in S41), the SOC calculation unit 34 acquires the monitoring data of the storage battery module 10 acquired by the monitoring data acquisition unit 32. (S42). The SOC calculation unit 34 calculates the current SOC of the storage battery module 10 based on the acquired monitoring data (S43).

When the current SOC of the storage battery module 10 is greater than the second upper limit capacity (Y in S44), the charge / discharge control unit 35 forcibly discharges the storage battery module 10 until the SOC of the storage battery module 10 reaches the second upper limit capacity. (S45). When the charge / discharge control unit 35 forcibly discharges the storage battery module 10 or the upper limit capacity of the storage battery module 10 is changed from the second upper limit capacity to the first upper limit capacity (N in S41), or the current of the storage battery module 10 When the SOC is equal to or less than the second upper limit capacity (N in S44), the processing in this flowchart ends.

In the above description, the charge / discharge control unit 35 controls whether or not the storage battery module 10 is forcibly discharged based on a comparison of the magnitude relationship between the second upper limit capacity and the current SOC of the storage battery module 10. Explained the case. Instead of this, the charge / discharge control unit 35 is based on the magnitude relationship between the current voltage of the storage battery module 10 and the release voltage of the storage battery module 10 when the storage amount of the storage battery module 10 is the second upper limit capacity. Whether or not the storage battery module 10 is forcibly discharged may be controlled.

For example, when the current voltage of the storage battery module 10 acquired by the monitoring data acquisition unit 32 is higher than the voltage V _t or V _t ′ corresponding to the above-described second upper limit capacity, the charge / discharge control unit 35 determines that the storage battery module 10 This can be realized by forcibly discharging. Since the SOC calculation process by the SOC calculation unit 34 can be omitted, it is not necessary to use a highly accurate SOC calculation method, which is advantageous in that the calculation is further simplified.

As described above, according to the second modification of the present invention, the life of the storage battery module 10 for assisting the system power supply can be extended.

In the second modification of the present invention, when the solar power generation system 300 is linked to the power storage system 100 connected to the system power supply 200, the solar power generation system 300 is connected to the power storage system 100 via the PV power conditioner 40. Connect to. That is, it was assumed that the storage battery module 10 and the system power supply 200 were connected with an AC output. However, those skilled in the art can easily understand that the second modification of the present invention can also be applied to a system in which the photovoltaic power generation system 300 is connected to the direct current side of the storage battery power conditioner 20.

In the above embodiment and each modification, the example in which the photovoltaic power generation system 300 is linked to the power storage system 100 connected to the system power supply has been described. In this regard, the power storage system according to the present invention can be linked to a power generation apparatus that generates power based on renewable energy other than the solar power generation system 300. For example, a wind power generator or a micro hydroelectric generator with a direct current output is applicable.

The invention according to the present embodiment may be specified by the items described below.

[Item 1-1]
A storage battery,
A first inverter that converts AC power to DC power when charging the storage battery, and converts DC power to AC power when discharging from the storage battery;
A second inverter that converts DC power generated by a power generation device that generates power based on renewable energy into AC power;
An AC current path for conducting the AC side terminal of the first inverter, the AC side terminal of the second inverter, and a system power supply;
A power storage system comprising:
[Item 1-2]
The AC current path is connected to a predetermined specific load that can receive power supply from the storage battery or the power generation device preferentially in the event of a power failure of the system power supply. 2. The power storage system according to 1.
[Item 1-3]
A heater, a fan, and a management device;
3. The power storage system according to item 1-1 or 1-2, wherein the management device operates the heater and the fan when the storage battery is heated.
[Item 1-4]
4. The power storage system according to item 1-3, wherein the management device controls the heater and the fan to be non-operating in a state where the storage battery is not discharged during a power failure.
[Item 1-5]
A management device for managing the storage battery,
The management device acquires information indicating whether or not the power generation device is generating power from the second inverter, and the power generation device is not generating power in a state in which the storage battery is not discharged at the time of a power failure of the system power supply In this case, the power storage system according to item 1-1 or 1-2, wherein the power source of the first inverter and the second inverter is turned off, or the first inverter and the second inverter are caused to sleep.

[Item 2-1]
An upper limit capacity setting unit that sets either the first upper limit capacity or the second upper limit capacity smaller than the first upper limit capacity as the upper limit capacity of the electric power charged in the storage battery;
A user input receiving unit that obtains an instruction from the user as to whether the upper limit capacity setting unit sets the first upper limit capacity or the second upper limit capacity;
A charge / discharge control unit for managing charge / discharge of the storage battery,
The charge / discharge control unit has a remaining capacity of the storage battery larger than the second upper limit capacity when the setting of the upper limit capacity is changed from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input receiving unit. When the storage battery management device, the storage battery is forcibly discharged until the remaining capacity of the storage battery reaches a second upper limit capacity.
[Item 2-2]
The storage battery is for assisting the system power supply,
Acquire from the user whether to use the setting during power failure to discharge the storage battery when the system power supply fails or the power usage setting to discharge the storage battery even when the power of the system power supply is supplied A user input receiving unit that
The charge / discharge control unit changes the upper limit capacity setting from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input reception unit even if the use setting at the time of power failure is set by the instruction acquired by the user input reception unit. When the remaining capacity of the storage battery is larger than the second upper limit capacity, the storage battery is forcibly discharged until the remaining capacity of the storage battery reaches the second upper limit capacity. The storage battery management device according to -1.
[Item 2-3]
The charge / discharge control unit changes the upper limit capacity setting from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input accepting unit when the use input setting is set by the instruction acquired by the user input accepting unit. When the remaining capacity of the storage battery is larger than the second upper limit capacity, the storage battery is forcibly discharged until the remaining capacity of the storage battery reaches the second upper limit capacity. The storage battery management apparatus according to -1 or 2-2.
[Item 2-4]
Item 4. The storage battery management device according to item 2-2 or 2-3, wherein the forced discharge causes the power of the storage battery to flow to a load or a system power source.

100 power storage system, 110 housing, 111 first air hole, 112 handle, 113 second air hole, 114 third air hole, 115, 116 inlet hole, 10 storage battery module, 11 storage battery cell, 12 voltage sensor, 13 current sensor , 14 temperature sensor, 20 storage battery power conditioner, 21 bidirectional inverter, 22 control circuit, 30, 130 storage battery management device, 31 communication unit, 32 monitoring data acquisition unit, 33 user input reception unit, 34 SOC calculation unit, 35 charge Discharge control unit, 36 Power generation control unit, 37 Temperature control unit, 38 Fan / heater control unit, 39 Switch control unit, 40 PV power conditioner, 41 inverter, 42 control circuit, 50 inverter , 60 storage battery fan, 70 heater, 200 system power supply, 300 solar power generation system, 400 general load, 500 specific load, 600 temperature sensor, S1 first switch, S2 second switch, S3 third switch, S4 fourth switch , S5 5th switch, S6 6th switch, S7 7th switch, S8 8th switch, S9 9th switch, B1 1st breaker, B2 2nd breaker, B3 3rd breaker, 132 upper limit capacity setting section, 134 use setting Memory part.

The present invention can be used in a power storage system including a storage battery for assisting a system power supply.

Claims

An upper limit capacity setting unit that sets either the first upper limit capacity or the second upper limit capacity smaller than the first upper limit capacity as the upper limit capacity of the electric power charged in the storage battery;
A user input receiving unit that obtains an instruction from the user as to whether the upper limit capacity setting unit sets the first upper limit capacity or the second upper limit capacity;
A charge / discharge control unit for managing charge / discharge of the storage battery,
The charge / discharge control unit has a remaining capacity of the storage battery larger than the second upper limit capacity when the setting of the upper limit capacity is changed from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input receiving unit. When the storage battery management device, the storage battery is forcibly discharged until the remaining capacity of the storage battery reaches a second upper limit capacity.
The storage battery is for assisting the system power supply,
Acquire from the user whether to use the setting during power failure to discharge the storage battery when the system power supply fails or the power usage setting to discharge the storage battery even when the power of the system power supply is supplied A user input receiving unit that
The charge / discharge control unit changes the upper limit capacity setting from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input reception unit even if the use setting at the time of power failure is set by the instruction acquired by the user input reception unit. When the remaining capacity of the storage battery is larger than the second upper limit capacity, the storage battery is forcibly discharged until the remaining capacity of the storage battery reaches the second upper limit capacity. The storage battery management apparatus according to 1.
The charge / discharge control unit changes the upper limit capacity setting from the first upper limit capacity to the second upper limit capacity according to the instruction acquired by the user input accepting unit when the use input setting is set by the instruction acquired by the user input accepting unit. When the remaining capacity of the storage battery is larger than the second upper limit capacity, the storage battery is forcibly discharged until the remaining capacity of the storage battery reaches the second upper limit capacity. 2. The storage battery management device according to 2.
4. The storage battery management apparatus according to claim 2, wherein the forced discharge causes the power of the storage battery to flow to a load or a system power supply.