Battery storage system

Abstract

This technology uses battery charge / discharge control to provide a more economical way to use power from the commercial power grid to supply power to residential loads. [Solution] The storage battery system 100 of the present disclosure is a system that cooperates with an AC power circuit 2 to which a residential load 4 and a commercial power system 3 are connected, and includes a storage battery 410 configured to be able to transmit power to and receive power from the AC power circuit 2, a power conversion unit 420, and a server 300 that controls the power conversion unit 420 to charge and discharge the storage battery 410. The server 300 repeatedly sets a future charge and discharge pattern for the storage battery 410 at a predetermined cycle based on predetermined external information that has been made public in advance, and charges and discharges the storage battery 410 by switching the operation of the power conversion unit 420 based on the charge and discharge pattern.

Description

[Technical Field]

[0001] The present invention relates to a storage battery system that is linked to an AC power line to which residential loads and a commercial power system are connected. [Background technology]

[0002] Power supply systems that combine distributed power sources, such as solar power generation, with storage batteries are known. Such power supply systems are expected to be highly economical when using electricity. For example, by preferentially supplying electricity from distributed power sources or stored in storage batteries to residential loads, it may be possible to reduce the cost of electricity supplied from the commercial power grid.

[0003] Furthermore, demand for electricity tends to increase during the day and decrease at night. For this reason, electricity rates on commercial power grids are sometimes discounted during the night when demand for electricity is particularly low. Taking advantage of such low-price rates during the night, night-time energy storage systems have been developed that charge a battery with electricity from the commercial power grid during the night and discharge the stored electricity during the day to supply power to residential loads.

[0004] For example, Patent Document 1 discloses a power storage system that stores commercial power in a storage battery during late-night hours and discharges the storage battery according to the amount of power consumed by a load at times other than late-night hours to supply power to the load. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-130606 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional energy storage systems charge a battery with power from a commercial power grid during the night and then discharge the stored power during the day to supply residential loads, thereby improving the economic efficiency of power usage. However, such energy storage batteries are still expensive for home use, and the larger the storage capacity, the more expensive they become. Therefore, the storage capacity of batteries used for residential loads is relatively small, and the amount of power charged from the commercial power grid during the night is also limited. As a result, if a distributed power source is not installed in addition to the battery in the energy storage system, or if a distributed power source is installed but the distributed power source is not generating enough power due to environmental factors, the amount of power charged from the commercial power grid during the night may be insufficient to supply power to residential loads, resulting in a situation where the residential loads must rely on power from the commercial power grid.

[0007] According to the technology described in Patent Document 1, the storage battery is discharged according to the amount of power consumed by the load, and it appears that the battery is controlled to charge and discharge in accordance with the amount of power required according to fluctuations in the load. However, this technology is only designed to store commercial power during the night, and the charging pattern of the storage battery is uniform. Therefore, if power is supplied from the commercial power grid outside of the night, there is a risk that the economical effectiveness of power usage will be compromised. As such, there is still room for improvement in technology for more economically utilizing power from the commercial power grid to supply power to residential loads.

[0008] An object of the present disclosure is to provide a technology that uses charge / discharge control of a storage battery to more economically utilize power from a commercial power grid to supply power to residential loads. [Means for solving the problem]

[0009] The storage battery system disclosed herein is a storage battery system linked to an AC electric circuit to which a residential load and a commercial power grid are connected, the storage battery system being connected to the AC electric circuit and configured to be able to transmit power to and receive power from the AC electric circuit, a power conversion unit disposed between the AC electric circuit and the storage battery and having the functions of converting DC discharged from the storage battery into AC and transmitting the power to the AC electric circuit, and converting AC supplied from the AC electric circuit into DC and charging the storage battery, and a server device controlling the power conversion unit to charge and discharge the storage battery. The server device repeatedly sets a future charge and discharge pattern for the storage battery at a predetermined cycle based on predetermined external information that has been made public in advance, and charges and discharges the storage battery by switching the operation of the power conversion unit based on the charge and discharge pattern. In this case, the external information may be the market price of electricity trading that is published daily, and may include the market price for each of the segments into which 24 hours are divided into a predetermined number of segments, and the server device may set the charging / discharging pattern for the day after the publication date of the market price at a predetermined timing on the publication date.

[0010] The server device may set the charging / discharging pattern to a first pattern including a charging reservation to charge the storage battery, a discharging reservation to discharge the storage battery, and a standby reservation to not charge or discharge the storage battery, wherein the charging reservation is in the category in which the market price belongs to a first range, the discharging reservation is in the category in which the market price belongs to a second range in which the market price is higher than the first range, and the standby reservation is in the category in which the market price is higher than the first range and lower than the second range.

[0011] In this case, the server device is further provided with a detection device that detects the state of charge of the storage battery and a power consumption measuring device that measures the amount of power consumed by the residential load, and the server device is configured to be able to acquire the state of charge of the storage battery detected by the detection device, the amount of power consumed by the residential load measured by the power consumption measuring device, and a standard consumption pattern of power consumption in the residential load based on the amount of power consumed, and predicts an initial state of charge, which is the state of charge of the storage battery at the start of the day following the publication date of the market price, based on the state of charge of the storage battery at the timing and the standard consumption pattern, and if there is a category in the category belonging to the first range in which the state of charge of the storage battery based on the initial state of charge and the first pattern is fully charged, the charging reservation in that category may be changed to a standby reservation. Furthermore, the server device may change the charging reservation in any of the divisions belonging to the first range to a standby reservation if the amount of charging to the storage battery based on the initial charging state and the first pattern in the division belonging to the first range is greater than the amount of discharging from the storage battery in the division belonging to the second range, and may change the standby reservation in the division belonging to the third range to a charging reservation for the amount of power that is the difference between the charging amount and the discharging amount in the division belonging to the first range if the amount of charging to the storage battery based on the initial charging state and the first pattern in the division belonging to the first range is equal to or less than the amount of discharging from the storage battery in the division belonging to the second range.

[0012] In addition, in the above-mentioned storage battery system, the server device may set the charging / discharging pattern to a second pattern including a charging reservation for charging the storage battery and a discharging reservation for discharging the storage battery, wherein the charging reservation is in the category in which the market price belongs to a first range, the category in which the market price belongs to a second range in which the market price is higher than the first range, and the discharging reservation is in the category in which the market price is higher than the first range and lower than the second range.

[0013] In this case, the server device is further provided with a detection device that detects the state of charge of the storage battery and a power consumption measuring device that measures the amount of power consumed by the residential load, and the server device is configured to be able to acquire the state of charge of the storage battery detected by the detection device, the amount of power consumed by the residential load measured by the power consumption measuring device, and a standard consumption pattern of power consumption in the residential load based on the amount of power consumed, and predicts an initial state of charge, which is the state of charge of the storage battery at the start of the day following the publication date of the market price, based on the state of charge of the storage battery at the timing and the standard consumption pattern, and when the initial state of charge and the second pattern are applied to the standard consumption pattern, if there is a category in the category belonging to the first range in which the state of charge of the storage battery is fully charged, the charging reservation in that category may be changed to a discharging reservation. Furthermore, when the server device applies the initial charge state and the second pattern to the standard consumption pattern, if the charge state of the storage battery at the start of the section belonging to the second range is not fully charged, the server device may change the discharge reservation in the section immediately preceding the start section of the second range to the charge reservation; and when the server device applies the initial charge state and the second pattern to the standard consumption pattern, if the charge state of the storage battery is empty in the section immediately following the end section of the second range, the server device may change the discharge reservation in the section immediately preceding the start section of the first range to the charge reservation.

[0014] In addition, the storage battery system of the present disclosure may further include an input / output device that outputs the charge / discharge pattern for the day after the publication date of the market price at the timing of the publication date and accepts input of a request to change the charge / discharge pattern, and the server device may change the charge / discharge pattern based on the change request input via the input / output device. [Effects of the Invention]

[0015] According to the present disclosure, by using charge / discharge control of a storage battery, it is possible to more economically utilize power from a commercial power grid to supply power to residential loads. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing a schematic configuration of a storage battery system according to a first embodiment. [Figure 2] 1 is a diagram illustrating the connection with an AC electric circuit in a storage battery system according to a first embodiment, based on a schematic circuit configuration. [Figure 3] FIG. 3 is a diagram illustrating an example of the flow of operation of the storage battery system in the first embodiment. [Figure 4] FIG. 2 is a first diagram illustrating the market price of electricity trading and a standard consumption pattern of electricity consumption in a residential load in the first embodiment. [Figure 5] FIG. 3 is a first diagram for explaining a charge / discharge pattern of a storage battery set in the first embodiment. [Figure 6] FIG. 4 is a second diagram for explaining the charge / discharge pattern of the storage battery set in the first embodiment. [Figure 7] FIG. 2 is a second diagram illustrating the market price of electricity trading and a standard consumption pattern of electricity consumption in residential loads in the first embodiment. [Figure 8] 10 is a flowchart showing a processing flow performed by a server based on the amount of charge to a storage battery in a section belonging to a first range and the amount of discharge from a storage battery in a section belonging to a second range. [Figure 9] FIG. 10 is a third diagram illustrating the market price of electricity trading and a standard consumption pattern of electricity consumption in residential loads in the first embodiment. [Figure 10] FIG. 4 is a fourth diagram illustrating the market price of electricity trading and the standard consumption pattern of electricity consumption in residential loads in the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The configurations of the following embodiments are examples, and the present disclosure is not limited to the configurations of the embodiments.

[0018] First Embodiment An overview of a storage battery system according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing a schematic configuration of a storage battery system according to this embodiment. A storage battery system 100 according to this embodiment includes a network 200, a server 300, and a power storage device 400. The storage battery system according to the present disclosure is a system that cooperates with an AC circuit to which a residential load and a commercial power system are connected.

[0019] Network 200 is, for example, an IP network. As long as network 200 is an IP network, it may be wireless, wired, or a combination of wireless and wired. For example, in the case of wireless communication, user terminal 400 may access a wireless LAN access point (not shown) and communicate with server 300 via a LAN or WAN. Furthermore, network 200 is not limited to these examples and may be, for example, a public switched telephone network, an optical fiber line, an ADSL line, a satellite communication network, etc.

[0020] The server 300 is connected to the power storage device 400 via the network 200. For ease of explanation, one server 300 and four power storage devices 400 are shown in FIG. 1, but it goes without saying that the number of servers 300 and four power storage devices 400 is not limited to this.

[0021] Server 300 may be any electronic device having the processing power for arithmetic and processing operations such as data acquisition, generation, and updating, including personal computers, servers, mainframes, and other electronic devices. That is, server 300 may be configured as a computer having a processor such as a CPU or GPU, a main memory such as RAM or ROM, and an auxiliary memory such as an EPROM, a hard disk drive, or removable media. The removable media may be, for example, a USB memory or a disk recording medium such as a CD or DVD. The auxiliary memory stores an operating system (OS), various programs, various tables, and the like.

[0022] In addition, the server 300 may appropriately use SaaS (Software as a Service), Paas (Platform as a Service), or IaaS (Infrastructure as a Service) using a cloud server, without providing software, hardware, an OS, etc. dedicated to the storage battery system of this embodiment.

[0023] The power storage device 400 is a device installed in a house to which the service using the battery system 100 is applied, and includes a storage battery 410, a power conversion unit 420, and a communication unit 430.

[0024] Next, the connection between the storage battery system 100 and an AC electric circuit will be described with reference to Fig. 2. Fig. 2 is a diagram illustrating the connection between the storage battery system 100 according to this embodiment and an AC electric circuit based on a schematic circuit configuration.

[0025] A commercial power grid 3 and residential loads 4 are connected to an AC circuit 2 in a distribution board 1 of a home to which a service using the battery storage system 100 is applied, and the home is configured so that power can be supplied from the commercial power grid 3 to the residential loads 4. Note that for the sake of simplicity, only one residential load 4 is shown in FIG. 2 , but in reality, the distribution board 1 has the function of distributing power to multiple residential loads 4. In addition, a power consumption measuring device 5 is installed in the circuit to the residential load 4, which measures the power consumption of the residential load 4 based on the current and voltage.

[0026] A power storage device 400 is connected to the AC electric circuit 2. Inside the power storage device 400, a power conversion unit 420 is connected to the AC electric circuit 2 via a grid interconnection relay 421. The power conversion unit 420 is a device, such as a bidirectional inverter, that converts DC discharged from the storage battery 410 into AC and transmits the AC electric power to the AC electric circuit 2, and converts AC supplied from the AC electric circuit 2 into DC and charges the storage battery 410. The power conversion unit 420 has its switching operation controlled based on a control command from the server 300, thereby switching the operating state of the storage battery 410 between charging and discharging. The control command from the server 300 is acquired via a communication unit 430. The communication unit 430 is a communication interface for connecting the power storage device 400 to the network 200, and includes, for example, a network interface board and a wireless communication circuit for wireless communication.

[0027] Furthermore, within the power storage device 400, a storage battery 410 is connected to a power conversion unit 420 via a grid interconnection relay 411. Here, the storage battery 410 is, for example, a lithium ion battery. The storage battery 410 is provided with a BMS (Battery Management System) 412. The BMS 412 is a device that detects various information related to the storage battery 410, such as the state of charge (SOC), terminal voltage, cell voltage, and temperature of the storage battery 410, and corresponds to a detection device in the present disclosure. The information is then sent to the server 300 via a communication unit 430.

[0028] The server 300 has, as functional units, a communication unit 301, a storage unit 302, and a control unit 303. The server 300 loads a program stored in an auxiliary storage device into a working area of ​​a main storage device and executes it. The execution of the program controls each functional unit, thereby realizing each function that matches the predetermined purpose of each functional unit. However, some or all of the functions may be realized by hardware circuits such as ASICs and FPGAs.

[0029] Here, the communication unit 301 is a communication interface for connecting the server 300 to the network 200. The communication unit 301 is configured to include, for example, a network interface board and a wireless communication circuit for wireless communication. The server 300 is connected to the power storage device 400 and other external devices via the communication unit 301 so as to be able to communicate with them.

[0030] The storage unit 302 is configured to include a main storage unit and an auxiliary storage unit. The main storage unit is a memory in which programs executed by the control unit 303 and data used by the control programs are developed. The auxiliary storage unit is a device in which programs executed by the control unit 303 and data used by the control programs are stored. The storage unit 302 also stores data transmitted from the power storage device 400 and other external devices, and stores the market price of electricity trading, which will be described later, and the like. The server 300 acquires the data transmitted from the power storage device 400 and other external devices via the communication unit 301.

[0031] The control unit 303 is a functional unit that manages the control performed by the server 300. The control unit 303 can be realized by an arithmetic processing unit such as a CPU. The control unit 303 further includes four functional units: a first acquisition unit 3031, a second acquisition unit 3032, a setting unit 3033, and a command unit 3034. Each functional unit may be realized by the CPU executing a stored program.

[0032] The first acquisition unit 3031 is a functional unit that acquires predetermined external information that has been made public in advance. Here, the external information in this embodiment is the market price of electricity trading that is made public at predetermined periodic times. Note that the external information in this disclosure is not intended to be limited to this, and the external information may be, for example, meteorological information based on a weather forecast. The first acquisition unit 3031 acquires such external information by accessing an external device (including an external public website) and stores it in the storage unit 302.

[0033] The second acquisition unit 3032 is a functional unit that acquires information from the power storage device 400. In this embodiment, the second acquisition unit 3032 acquires the state of charge (SOC) of the storage battery 410 detected by the BMS 412 of the power storage device 400 through communication with the power storage device 400, and stores the acquired information in the storage unit 302.

[0034] The setting unit 3033 is a functional unit that repeatedly sets a future charge / discharge pattern for the storage battery 410 at a predetermined cycle based on the above external information. Details of the processing executed by the setting unit 3033 will be described later with reference to FIG. 3.

[0035] The command unit 3034 is a functional unit that commands the power conversion unit 420 to change the switching operation based on the above-mentioned charge / discharge pattern.

[0036] Here, the flow of operation of the storage battery system 100 in this embodiment will be described. Fig. 3 is a diagram illustrating the flow of operation of the storage battery system 100 in this embodiment. Fig. 3 explains the flow of operation between the server 300, the power storage device 400, and the external device in the storage battery system 100 in this embodiment, and the processes executed by the server 300, the power storage device 400, and the external device.

[0037] In this embodiment, when the market price of electricity trading is published on an external device (the website of the electricity exchange) (S101), the server 300 acquires information about the market price (S102). Here, the market price of electricity trading is published at predetermined periodic times, and in this embodiment, it is the market price of electricity trading in the day-ahead market, where electricity trading for the next day is conducted on the day before the electricity delivery date. Note that the market price of electricity trading in such a day-ahead market is published every day.

[0038] For more details, the market prices for the above electricity transactions are published as spot market prices on the website of the Japan Electric Power Exchange (JEPX), a general incorporated association. These market prices are set on the day before the delivery date of the electricity for each of the 48 30-minute segments for the 24 hours of the following day.

[0039] Next, in the power storage device 400, the BMS 412 detects the current state of charge (SOC) of the storage battery 410 (S103). Then, information regarding the current state of charge (SOC) of the storage battery 410 is transmitted from the power storage device 400 to the server 300, and the server 300 acquires the information (S104).

[0040] The server 300 then sets a charge / discharge pattern for the storage battery 410 for the next day based on the market price of the electricity trade acquired in the process of S102 (S105). The server 300 then transmits to the power storage device 400 a command regarding charge reservation / discharge reservation for the storage battery 410 based on the charge / discharge pattern set in the process of S105. Here, the command commands the power conversion unit 420 to switch the switching operation based on the charge / discharge pattern. When the storage battery 410 acquires information regarding the command (S106), the power conversion unit 420 switches its switching operation based on the command regarding the charging and discharging operating state of the storage battery 410 for the next day. Hereinafter, the setting of the charge / discharge pattern for the storage battery 410 in the process of S105 will be described with reference to FIGS. 4 to 10.

[0041] FIG. 4 is the first diagram illustrating the market price of electricity trading and the standard consumption pattern of electricity consumption in the residential load 4 in this embodiment, where FIG. 4(a) illustrates the market price of electricity trading and FIG. 4(b) illustrates the standard consumption pattern of electricity consumption in the residential load 4.

[0042] As mentioned above, the market price for spot market electricity trading published on the website of the Japan Electric Power Exchange (JEPX), a general incorporated association, is set on the day before the electricity delivery date for each of the 48 30-minute segments of the 24 hours of the following day, and as shown in Figure 4(a), the unit price of electricity fluctuates for each 30-minute segment.

[0043] As described above, since the market price of electricity trading fluctuates, when setting the charging / discharging pattern of the storage battery 410, the server 300 sets the charging / discharging pattern to a first pattern including a charging reservation for charging the storage battery 410, a discharging reservation for discharging the storage battery 410, and a standby reservation for not charging or discharging the storage battery 410, and including a charging reservation in a category where the market price belongs to a first range, a discharging reservation in a category where the market price belongs to a second range where the market price is higher than the first range, and a standby reservation in a category where the market price belongs to a third range where the market price is higher than the first range and lower than the second range.

[0044] In the example shown in Figure 4(a), the difference between the lowest and highest market prices of electricity trading over a 24-hour period is calculated. Then, when the range between the lowest and highest prices is divided into thirds by this difference, the range on the lowest price side is defined as the above-mentioned first range (the low category in Figure 4(a)), the range on the highest price side is defined as the above-mentioned second range (the high category in Figure 4(a)), and the range between these is defined as the above-mentioned third range (the normal category in Figure 4(a)).

[0045] Furthermore, the server 300 acquires a standard consumption pattern of power consumption in the residential load 4 based on the amount of power consumption of the residential load 4 measured by a power consumption measuring device 5 installed on an electric path to the residential load 4. Here, the standard consumption pattern is defined as a standard pattern of power consumption in the residential load 4, and the server 300 can acquire the standard consumption pattern based on the past amount of power consumption of the residential load 4 measured by the power consumption measuring device 5, for example, by averaging the history of the past amount of power consumption of the residential load 4. Note that if the external information includes meteorological information based on a weather forecast, the server 300 may take into account the temperature of the next day, for example, predict the operating state of heating and cooling equipment based on the temperature, and reflect the power consumption based on the operating state in the standard consumption pattern that can be acquired as described above.

[0046] Specifically, the standard consumption pattern of the electricity consumption in the residential load 4 can be defined as a pattern in which the first peak occurs in the morning hours and the second peak occurs in the evening and night hours, as shown in FIG. 4(b).

[0047] FIG. 5 is a first diagram illustrating a charge / discharge pattern of the storage battery 410 set in this embodiment. In the example shown in FIG. 5, a charge reservation is made in a section belonging to a first range of the market price, where the price is relatively low, and a discharge reservation is made in a section belonging to a second range of the market price, where the price is relatively high. A standby reservation is made in a section belonging to a third range of the market price, where the price is relatively normal. This allows the storage battery 410 to charge power from the commercial power grid 3 during a time period (section) when the price is relatively low and discharge power from the storage battery 410 to the residential load 4 during a time period (section) when the price is relatively high, thereby enabling economical use of power from the commercial power grid 3. Furthermore, as described above, a standby reservation time period (section) is set, and during this time, power from the commercial power grid 3 is supplied to the residential load 4 via the AC circuit 2 in the distribution board 1. This allows the power stored in the storage battery 410 to be discharged intensively during a time period (zone) when the price is relatively high, thereby minimizing the need for power supply from the commercial power grid 3, which has a relatively high price, during that time period. This allows for more economical use of power from the commercial power grid 3. Furthermore, this charge / discharge pattern is set at a predetermined timing on the day when the market price is published as the charge / discharge pattern for the day following the publication date, and this setting of the charge / discharge pattern is repeated periodically every day. Therefore, the charge / discharge pattern of the storage battery 410 is not set uniformly every day as in the prior art, but rather flexibly changes depending on the market price. This allows for more economical use of power from the commercial power grid 3 to supply power to the residential loads 4 by controlling the charge / discharge of the storage battery 410. Note that the timing may be when the market price is published or before midnight on the day when the market price is published.

[0048] FIG. 5 shows the charge / discharge pattern of the storage battery 410 on the day after the publication date of the market price of electricity trading, along with price range categories, predicted values ​​of the state of charge (SOC) of the storage battery 410, and a charging flag for each category of the market price (category 1 represents 00:00 to 00:30, and the number of categories increases by one every 30 minutes thereafter). Here, the price range category is any of the first range (low price category in FIG. 4(a)), the second range (high price category in FIG. 4(a)), and the third range (normal price category in FIG. 4(a)). The charging flag is a flag for switching the operating state of the storage battery 410 to a charging state in the switching operation of the power conversion unit 420 controlled by the server 300. When the charging flag is on, the operating state of the storage battery 410 is controlled to a charging state by the power conversion unit 420 based on a command from the server 300. 5 does not show a discharge flag for switching the operating state of the storage battery 410 to a discharge state in the switching operation of the power conversion unit 420 controlled by the server 300. In the example shown in FIG. 5, the discharge flag is turned on in the price range in the second range (the price range corresponding to the high price range in FIG. 5). That is, in the example shown in FIG. 5, the charge flag is turned on in the price range in the first range (the price range corresponding to the low price range in FIG. 5), the discharge flag is turned on in the price range in the second range (the price range corresponding to the high price range in FIG. 5), and standby reservation is performed in the price range in the third range (the price range corresponding to the normal price range in FIG. 5). As will be described later, the charge flag may be corrected based on a predicted value of the state of charge (SOC) of the storage battery 410.

[0049] In setting such a charge / discharge pattern, the server 300 first predicts the initial state of charge, which is the state of charge of the storage battery 410 at the start of the day after the market price is released, based on the state of charge (SOC) of the storage battery 410 at a predetermined timing on the market price release date and the standard consumption pattern. In the example shown in Fig. 5, the initial state of charge of the storage battery 410 in category 1 at the start of the day after the market price is released is predicted to be SOC 35%.

[0050] In the example shown in Figure 5, the charge / discharge control of storage battery 410 is reserved for standby during price ranges 1 to 22, which are the ranges in which prices normally fall within the third range (price range ranges in Figure 5), and the state of charge of storage battery 410 during this period is predicted to be SOC 35%.

[0051] Then, in the section where the price belongs to the first range (the section where the price range section corresponds to the low price section in FIG. 5), the charge flag is turned on as described above. Then, the state of charge of the storage battery 410 in the section that belongs to the first range is calculated based on the initial state of charge (SOC 35%) and the first pattern. In the example shown in FIG. 5, the server 300 predicts the SOC to be 50% in section 23, 65% in section 24, 80% in section 25, 95% in section 26, and 100% in section 27 using a predetermined charging rate for the storage battery 410.

[0052] Furthermore, if there is a section in the first range in which the state of charge of the storage battery 410 based on the initial state of charge and the first pattern is fully charged, the server 300 changes the charging reservation in that section to the standby reservation and sets the charge / discharge pattern of the storage battery 410. That is, in Fig. 5, in sections 23 to 31 in the first range, the state of charge of the storage battery 410 is fully charged by the charging operation in section 27, so the charge flags in sections 28 to 31 are turned off.

[0053] FIG. 6 is a second diagram illustrating the charge / discharge pattern of the storage battery 410 set in this embodiment. In the example shown in FIG. 6, a charge reservation is made in a segment belonging to a first range of the market prices, which is relatively low, and a discharge reservation is made in a segment belonging to a second range of the market prices, which is relatively high, and a segment belonging to a third range of the market prices, which is relatively normal. This allows power charged into the storage battery 410 from the commercial power grid 3 during a time period (segment) when the price is relatively low to be discharged from the storage battery 410 to the residential load 4 during other time periods (segments), thereby enabling economical use of power from the commercial power grid 3. In this case, because power is also discharged during a time period (segment) when the price is relatively normal, the power charged into the storage battery 410 from the commercial power grid 3 during the time period (segment) when the price is relatively low can be more actively supplied to the residential load 4.

[0054] 6, similar to FIG. 5, shows a charge / discharge pattern of the storage battery 410 on the day following the publication date of the market price of the electricity trading, with price range segments, predicted values ​​of the state of charge (SOC) of the storage battery 410, and a charge flag for each segment of the market price (segment 1 represents 00:00 to 00:30, and the number of segments increases by one every 30 minutes thereafter). Note that although the discharge flag is not shown in FIG. 6, in the example shown in FIG. 6, the discharge flag is turned on for segments other than those in which the price belongs to the first range (segments corresponding to the low price range segment in FIG. 6). That is, in the example shown in FIG. 6, the charge flag is turned on for segments in which the price belongs to the first range (segments corresponding to the low price range segment in FIG. 6), and the discharge flag is turned on for segments other than those. However, if the state of charge (SOC) of the storage battery 410 is empty, a discharge operation from the storage battery 410 is not actually performed even if the discharge flag is on. As will be described later, the charge flag and the discharge flag can be corrected based on a predicted value of the state of charge (SOC) of the storage battery 410.

[0055] In setting such a charge / discharge pattern, the server 300 first predicts the initial state of charge, which is the state of charge of the storage battery 410 at the start of the day after the market price is released, based on the state of charge (SOC) of the storage battery 410 at a predetermined timing on the market price release date and the standard consumption pattern. In the example shown in Fig. 6, the initial state of charge of the storage battery 410 in category 1 at the start of the day after the market price is released is predicted to be SOC 30%.

[0056] In the example shown in Figure 6, discharge reservations are also made in categories 1 to 22, which are categories in which the price falls within the third range (categories to which the price range categories normally fall in Figure 6), so the SOC of the storage battery 410 during this period is predicted based on the initial charge state and the standard consumption pattern described above.

[0057] Then, in the section where the price belongs to the first range (the section where the price range section corresponds to low in FIG. 6), the charge flag is turned on as described above. Then, the state of charge of the storage battery 410 in the section that belongs to the first range is calculated, and in the example shown in FIG. 6, the server 300 predicts that the SOC will be 15% in section 23, 30% in section 24, 45% in section 25, 60% in section 26, 75% in section 27, 90% in section 28, and 100% in section 29.

[0058] Then, when the initial charge state and the second pattern are applied to the standard consumption pattern, if there is a section in the first range in which the charge state of the storage battery 410 is fully charged, the server 300 changes the charge reservation in that section to a discharge reservation and sets the charge / discharge pattern of the storage battery 410. That is, in FIG. 6 , in sections 23 to 31 in the first range, the charge state of the storage battery 410 is fully charged by the charging operation in section 29. Therefore, in section 30, the charge flag is turned off and the discharge flag is turned on. Then, because the charge state of the storage battery 410 is no longer fully charged due to discharge from the storage battery 410 in section 30, in the next section 31, the charge flag is turned on again and the discharge flag is turned off.

[0059] Furthermore, when the initial state of charge and the second pattern are applied to the standard consumption pattern, if the state of charge of the storage battery 410 at the start of a segment belonging to the second range is not fully charged, the server 300 changes the discharge reservation in the segment immediately preceding the start segment of the second range to a charge reservation, thereby setting the charge / discharge pattern of the storage battery 410. That is, in FIG. 6 , segments 32 and 33 belonging to the third range are present between the segments (segments 23 to 31) belonging to the first range and the segments (segments 34 to 43) belonging to the second range. According to the second pattern, discharge is reserved at this time, so the state of charge of the storage battery 410 in segment 34, which is the start of a segment belonging to the second range, is not fully charged. Therefore, in the example shown in FIG. 6 , the server 300 turns off the discharge flag and turns on the charge flag in segment 33 immediately preceding the start segment of the second range. This makes it possible to continue discharging power from the storage battery 410 for a longer period of time (segment) thereafter, thereby enabling more economical use of power from the commercial power grid 3 to supply power to the residential loads 4 by using charge / discharge control of the storage battery 410.

[0060] 7 is a second diagram illustrating the market price of electricity trading and the standard consumption pattern of electricity consumption in the residential load 4 in this embodiment, where FIG. 7(a) illustrates the market price of electricity trading and FIG. 7(b) illustrates the standard consumption pattern of electricity consumption in the residential load 4. In the example shown in FIG. 7(a), a first range (low price range in FIG. 7(a)), a second range (high price range in FIG. 7(a)), and a third range (normal price range in FIG. 7(a)) are defined in the same way as in the example shown in FIG. 4(a) above.

[0061] 7(a) shows that the first range (the low-price range in FIG. 7(a)) is narrower than the example shown in FIG. 4(a) above. This may cause a risk that the amount of charge to the storage battery 410 in the range belonging to the first range will be insufficient compared to the amount of discharge from the storage battery 410.

[0062] Therefore, the server 300 compares the amount of charge to the storage battery 410 in the section belonging to the first range with the amount of discharge from the storage battery 410 in the section belonging to the second range, thereby setting a charge / discharge pattern for the storage battery 410. This will be described with reference to FIG. 8.

[0063] FIG. 8 is a flowchart showing a processing flow performed by the server 300 based on the amount of charge to the storage battery 410 in the section belonging to the first range and the amount of discharge from the storage battery 410 in the section belonging to the second range.

[0064] In this flow, first, in S1051, the amount of charge to the storage battery 410 based on the initial state of charge and the first pattern in the section belonging to the first range is predicted.

[0065] Next, in S1052, the amount of discharge from the storage battery 410 in the section belonging to the second range is predicted.

[0066] Then, in S1053, the server 300 determines whether the charge amount predicted in the process of S1051 is greater than the discharge amount predicted in the process of S1052. If the determination in the process of S1053 is affirmative, that is, if the charge amount is greater than the discharge amount, the server 300 proceeds to the process of S1054, and if the determination in the process of S1053 is negative, that is, if the charge amount is equal to or less than the discharge amount, the server 300 proceeds to the process of S1055.

[0067] If the determination in S1053 is affirmative, then in S1054, the server 300 changes a charging reservation in any of the sections belonging to the first range to a standby reservation, and sets a charging / discharging pattern for the storage battery 410. This makes it possible to charge in advance, without waste, only the amount of discharge from the storage battery 410 that is necessary to avoid receiving power supply from the commercial power grid 3 during a time period (section) when the price of power from the commercial power grid 3 is relatively high, during a time period (section) when the price is relatively low.

[0068] On the other hand, if the determination in S1053 is negative, then in S1055, the server 300 changes the standby reservation in the category belonging to the third range to a charge reservation for the amount of power that is the difference between the above-mentioned charge amount and the above-mentioned discharge amount, and sets the charge / discharge pattern of the storage battery 410. This will be described with reference to Figs. 9 and 10.

[0069] Fig. 9 is a third diagram for explaining the charge / discharge pattern of the storage battery 410 set in this embodiment. In the example shown in Fig. 9, similar to Fig. 5 above, a charge reservation is made in a category belonging to a first range of relatively low prices among the above market prices, a discharge reservation is made in a category belonging to a second range of relatively high prices among the above market prices, and a standby reservation is made in a category belonging to a third range of relatively normal prices among the above market prices.

[0070] Furthermore, according to the flow shown in Fig. 8 above, the charge flag and the standby flag may be corrected based on the predicted value of the state of charge (SOC) of the storage battery 410. In the example shown in Fig. 9, the amount of charge to the storage battery 410 based on the initial state of charge and the first pattern in the section belonging to the first range (which corresponds to an SOC of 60%) is less than the amount of discharge from the storage battery 410 in the section belonging to the second range (which corresponds to an SOC of 65%), so the standby reservation in the section belonging to the third range is changed to a charge reservation.

[0071] Specifically, the server 300 turns on the charge flag in section 26 (which belongs to the third range) immediately before the start section of the first range. This allows the storage battery 410 to be charged with the amount of power equal to the difference between the above-mentioned charge amount and the above-mentioned discharge amount (which corresponds to an SOC of 5%) in section 26, which belongs to the third range. This allows the storage battery 410 to be charged in advance in a section other than the time period when the price of power from the commercial power grid 3 is relatively high, so that the amount of power discharged from the storage battery 410 is sufficient to avoid receiving power from the commercial power grid 3 during that time period. This allows the power from the commercial power grid 3 to be used more economically for supplying power to the residential loads 4.

[0072] 10 is a fourth diagram illustrating a charge / discharge pattern of the storage battery 410 set in this embodiment. In the example shown in Fig. 10, similar to Fig. 6, a charge reservation is made in the category belonging to the first range of relatively low prices among the above-mentioned market prices, and a discharge reservation is made in the category belonging to the second range of relatively high prices among the above-mentioned market prices and the category belonging to the third range of relatively normal prices among the above-mentioned market prices.

[0073] 10, when the initial state of charge and the second pattern are applied to the standard consumption pattern, the state of charge of the storage battery 410 becomes empty in the segment immediately following the end segment of the second range, and therefore, similar to the above-described Fig. 9, the charge flag of segment 26, which is the segment immediately following the start segment of the first range and belongs to the third range, is turned on. At this time, in the example shown in Fig. 10, unlike the example shown in the above-described Fig. 9, as much power as possible (until the SOC reaches 15%) is charged to the storage battery 410 in segment 26.

[0074] 10, similarly to FIG. 6, when the initial state of charge and the second pattern are applied to the standard consumption pattern, if the state of charge of the storage battery 410 at the start of a segment belonging to the second range is not fully charged, the server 300 changes the discharge reservation in the segment immediately before the start segment of the second range to a charge reservation, thereby setting the charge and discharge pattern of the storage battery 410. That is, in FIG. 10, the server 300 turns off the discharge flag and turns on the charge flag in segment 33 immediately before the start segment of the second range. This makes it possible to continue discharging power from the storage battery 410 for a longer period of time (segment), and thus, by using the charge and discharge control of the storage battery 410, it is possible to more economically use power from the commercial power grid 3 to supply power to the residential loads 4.

[0075] A photovoltaic power generation panel and its power conditioner may be connected to the AC circuit 2 in the distribution board 1 of a home to which the service using the storage battery system 100 is applied. In this case, during solar power generation, the power conditioner performs grid-connected operation, converting the output (DC) of the photovoltaic power generation panel into AC generated power and transmitting it to the AC circuit 2. This allows power from the photovoltaic power generation panel to be supplied to the home load 4, for example, during a time period (zone) when the storage battery 410 is reserved for standby.

[0076] According to the storage battery system 100 described above, by using charge / discharge control of the storage battery 410, it is possible to use the power from the commercial power system 3 to supply power to the residential load 4 more economically.

[0077] <Modification of the first embodiment> A storage battery system 100 according to a modification of the first embodiment will be described below. The storage battery system 100 according to this modification further includes an input / output device in addition to the configuration described in the first embodiment. This input / output device outputs a charge / discharge pattern for the day after the market price is made public at the timing for setting the charge / discharge pattern, and also receives input of a request to change the charge / discharge pattern.

[0078] The input / output device includes a display device and an operation input device. The display device has a function of displaying various information and is realized by, for example, an LCD (Liquid Crystal Display), an LED (Light Emitting Diode) display, an OLED (Organic Light Emitting Diode) display, etc. The operation input device has a function of accepting operation input from a user and is realized specifically by soft keys or hard keys such as a touch panel.

[0079] Furthermore, by displaying the charge / discharge pattern for the next day on such an input / output device, the user is motivated to conserve electricity and not deviate from the charge / discharge pattern, thereby making it possible to use electricity from the commercial power system 3 more economically.

[0080] Furthermore, the user can determine in advance whether the power consumption of the residential load 4 on the next day will deviate from the standard consumption pattern based on the user's action plan for the next day. Alternatively, the server 300 can determine whether the power consumption of the residential load 4 on the next day will deviate from the standard consumption pattern based on the user's action plan for the next day acquired from the user.

[0081] Therefore, in this modification, the input / output device is configured to be able to accept input of a change request for the charge / discharge pattern. For example, if a user who has checked the charge / discharge pattern for the next day inputs a change request together with the user's action plan for the next day, the server 300 can change the standard consumption pattern based on the action plan and set the charge / discharge pattern of the storage battery 410 again using the changed standard consumption pattern.

[0082] The above-described storage battery system 100 also makes it possible to use the electric power from the commercial power grid 3 to supply electric power to the residential load 4 more economically by using charge / discharge control of the storage battery 410.

[0083] <Other variations> The above-described embodiment is merely an example, and the present disclosure may be modified as appropriate within the scope of the present disclosure. For example, the processes and means described in the present disclosure may be freely combined as long as no technical contradiction occurs.

[0084] In the above first embodiment, an example was described in which the server 300 is installed separately from the power storage device 400, but the functions of the server 300 described in the above first embodiment may also be built into the power storage device 400.

[0085] Furthermore, a process described as being performed by one device may be shared and executed by multiple devices. In this case, the separate arithmetic processing device is configured to be able to cooperate favorably with server 300. Furthermore, a process described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration (server configuration) by which each function is realized can be flexibly changed.

[0086] The present disclosure can also be realized by providing a computer program implementing the functions described in the above embodiments to a computer, and having one or more processors in the computer read and execute the program. Such a computer program may be provided to the computer via a non-transitory computer-readable storage medium connectable to the computer's system bus or via a network. Non-transitory computer-readable storage media include, for example, any type of disk, such as a magnetic disk (e.g., a floppy disk, a hard disk drive (HDD), etc.), an optical disk (e.g., a CD-ROM, a DVD disk, a Blu-ray disk), a read-only memory (ROM), a random access memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, an optical card, or any type of medium suitable for storing electronic instructions. [Explanation of symbols]

[0087] 2...AC line 3...Commercial power system 4... Residential load 100... Battery storage system 200···Network 300 Server 301···Communications Department 302...Storage section 303 Control section 400 Energy storage device 410... Battery 420 Power conversion unit

Claims

1. A storage battery system linked to an AC circuit to which a residential load and a commercial power system are connected, a storage battery connected to the AC electric circuit and configured to be able to transmit power to the AC electric circuit and receive power from the AC electric circuit; a power conversion unit disposed between the AC circuit and the storage battery, the power conversion unit converting DC discharged from the storage battery into AC and transmitting the AC power to the AC circuit, and converting AC power supplied from the AC circuit into DC and charging the storage battery; a server device that controls the power conversion unit to charge and discharge the storage battery; a detection device for detecting a state of charge of the storage battery; a power consumption measuring device for measuring the amount of power consumed by the residential load; The server device The charge / discharge pattern for the day following the publication date of the market price is set at a predetermined timing on the publication date based on external information including the market price of electricity trading that is published daily and that includes each market price for each predetermined number of segments into which 24 hours are divided, and the storage battery is charged / discharged by switching the operation of the power conversion unit based on the charge / discharge pattern, The charging and discharging pattern is set to a first pattern including a charging reservation for charging the storage battery, a discharging reservation for discharging the storage battery, and a standby reservation for not charging or discharging the storage battery, the first pattern including the charging reservation in the section in which the market price belongs to a first range, the discharging reservation in the section in which the market price belongs to a second range higher than the first range, and the standby reservation in the section in which the market price belongs to a third range higher than the first range and lower than the second range; acquiring the state of charge of the storage battery detected by the detection device, the amount of power consumption of the residential load measured by the power consumption measurement device, and a standard consumption pattern of power consumption in the residential load based on the amount of power consumption; predicting an initial state of charge, which is the state of charge of the storage battery at the start of the day following the publication date of the market price, based on the state of charge of the storage battery at the timing and the standard consumption pattern; When the amount of charge to the storage battery based on the initial charge state and the first pattern in the section belonging to the first range is greater than the amount of discharge from the storage battery in the section belonging to the second range, the charging reservation in any section belonging to the first range is changed to a standby reservation; When the charge amount to the storage battery based on the initial charge state and the first pattern in the section belonging to the first range is equal to or less than the discharge amount from the storage battery in the section belonging to the second range, the standby reservation in the section belonging to the third range is changed to the charge reservation for the amount of power that is the difference between the charge amount and the discharge amount. Battery storage system.

2. A battery system linked to an AC circuit to which residential loads and a commercial power system are connected, a storage battery connected to the AC electric circuit and configured to be able to transmit power to the AC electric circuit and receive power from the AC electric circuit; a power conversion unit disposed between the AC circuit and the storage battery, the power conversion unit converting DC discharged from the storage battery into AC and transmitting the AC power to the AC circuit, and converting AC power supplied from the AC circuit into DC and charging the storage battery; a server device that controls the power conversion unit to charge and discharge the storage battery; a detection device for detecting a state of charge of the storage battery; a power consumption measuring device for measuring the amount of power consumed by the residential load; The server device The charge / discharge pattern for the day following the publication date of the market price is set at a predetermined timing on the publication date based on external information including the market price of electricity trading that is published daily and that includes each market price for each predetermined number of segments into which 24 hours are divided, and the storage battery is charged / discharged by switching the operation of the power conversion unit based on the charge / discharge pattern, The charge / discharge pattern is set to a second pattern including a charge reservation for charging the storage battery and a discharge reservation for discharging the storage battery, the second pattern including the charge reservation in the section in which the market price belongs to a first range, the section in which the market price belongs to a second range higher than the first range, and the section in which the market price belongs to a third range higher than the first range and lower than the second range; and acquiring the state of charge of the storage battery detected by the detection device, the amount of power consumption of the residential load measured by the power consumption measurement device, and a standard consumption pattern of power consumption in the residential load based on the amount of power consumption; predicting an initial state of charge, which is the state of charge of the storage battery at the start of the day following the publication date of the market price, based on the state of charge of the storage battery at the timing and the standard consumption pattern; when the initial state of charge and the second pattern are applied to the standard consumption pattern, if the state of charge of the storage battery at the start of the segment belonging to the second range is not fully charged, the discharge reservation in the segment immediately before the start segment of the second range is changed to the charge reservation. Battery storage system.

3. A battery system linked to an AC circuit to which residential loads and a commercial power system are connected, a storage battery connected to the AC electric circuit and configured to be able to transmit power to the AC electric circuit and receive power from the AC electric circuit; a power conversion unit disposed between the AC circuit and the storage battery, the power conversion unit converting DC discharged from the storage battery into AC and transmitting the AC power to the AC circuit, and converting AC power supplied from the AC circuit into DC and charging the storage battery; a server device that controls the power conversion unit to charge and discharge the storage battery; a detection device for detecting a state of charge of the storage battery; a power consumption measuring device for measuring the amount of power consumed by the residential load; The server device The charge / discharge pattern for the day following the publication date of the market price is set at a predetermined timing on the publication date based on external information including the market price of electricity trading that is published daily and that includes each market price for each predetermined number of segments into which 24 hours are divided, and the storage battery is charged / discharged by switching the operation of the power conversion unit based on the charge / discharge pattern, The charge / discharge pattern is set to a second pattern including a charge reservation for charging the storage battery and a discharge reservation for discharging the storage battery, the second pattern including the charge reservation in the section in which the market price belongs to a first range, the section in which the market price belongs to a second range higher than the first range, and the section in which the market price belongs to a third range higher than the first range and lower than the second range; and acquiring the state of charge of the storage battery detected by the detection device, the amount of power consumption of the residential load measured by the power consumption measurement device, and a standard consumption pattern of power consumption in the residential load based on the amount of power consumption; predicting an initial state of charge, which is the state of charge of the storage battery at the start of the day following the publication date of the market price, based on the state of charge of the storage battery at the timing and the standard consumption pattern; when the initial state of charge and the second pattern are applied to the standard consumption pattern, if the state of charge of the storage battery becomes empty in a section immediately after the end section of the second range, the discharge reservation in the section immediately before the start section of the first range is changed to the charge reservation. Battery storage system.

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