Battery management device and battery management method

Abstract

To provide a storage battery management device and a storage battery management method capable of suppressing deterioration of life of a storage battery and efficiently using power of the storage battery.SOLUTION: A storage battery management device obtains a charging rate of a storage battery 51 electrically connected to a load, and capable of storing system power and power from a fuel battery, from the storage battery 51, predicts the charging rate of the storage battery 51 during a predetermined period, performs a first control of controlling the storage battery 51 so as to be able to charge up to a second charging rate higher than the first charging rate when the predicted charging rate of the storage battery 51 is smaller than the first charging rate, and performs a second control of controlling the storage battery 51 so as to be able to charge up to a third charging rate equal to or less than the first charging rate when the predicted charging rate of the storage battery 51 is equal to or more than the first charging rate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a storage battery management device and a storage battery management method for managing the charging rate of a storage battery. [Background technology]

[0002] There is known a power supply system in which a storage battery and a fuel cell are installed in a house, and the power stored in the storage battery and the power generated by the fuel cell are supplied to the load of the house, thereby reducing the amount of power purchased from the grid (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-32906 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-34185 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the power used by the load can be supplied solely by the power generated by the fuel cell, the power of the storage battery is not used and the storage battery is maintained at a fully charged or nearly fully charged state. Therefore, if the storage battery is maintained at a fully charged or nearly fully charged state for a long period of time, the storage battery will deteriorate and its lifespan will be shortened.

[0005] Furthermore, if the storage battery is maintained at a relatively low charging rate, when the fuel cell alone is not enough to cover the load power, the storage battery power cannot be fully utilized, resulting in an increase in the amount of power purchased from the grid.

[0006] In view of the above circumstances, an object of the present invention is to provide a storage battery management device and a storage battery management method that can prevent a decrease in the lifespan of a storage battery and efficiently use the power of the storage battery. [Means for solving the problem]

[0007] An aspect of the present invention that solves the above problem is a battery management device that acquires a charging rate of a storage battery from a storage battery that is electrically connected to a load and can store power from a grid power and a fuel cell, predicts the charging rate of the storage battery for a predetermined period of time, and, if the predicted charging rate of the storage battery is lower than a first charging rate, performs a first control to control the storage battery so that it can be charged to a second charging rate that is higher than the first charging rate, and, if the predicted charging rate of the storage battery is equal to or higher than the first charging rate, performs a second control to control the storage battery so that it can be charged to a third charging rate that is equal to or lower than the first charging rate.

[0008] In this mode, when it is expected that the storage battery will be used less during the predetermined period, the storage battery can be maintained at the relatively low third charging rate, thereby reducing deterioration of the storage battery. Also, when it is expected that the storage battery will be used more during the predetermined period, the storage battery can be maintained at the relatively high second charging rate, thereby increasing the power available for the storage battery load and reducing the amount of power purchased from the grid.

[0009] Here, it is preferable that the storage battery is used with a fourth charging rate lower than the third charging rate as a lower limit value. By using the storage battery with the fourth charging rate as a lower limit value, the storage battery can be used as an emergency power source in the event of an emergency such as a power outage, thereby improving user convenience.

[0010] Furthermore, when the charging rate of the storage battery becomes lower than the fourth charging rate, it is preferable to charge the storage battery so that it exceeds at least the fourth charging rate. According to this, if the power of the storage battery is used in an emergency until the charging rate becomes lower than the fourth charging rate, by charging the storage battery until the charging rate becomes at least equal to or higher than the fourth charging rate upon recovery, it is possible to use the storage battery as an emergency power source up to the fourth charging rate at the next power outage if power outages occur repeatedly.

[0011] Furthermore, if the supply from the grid power is stopped while the second control is being performed, it is preferable to switch to the first control. According to this, if the supply from the grid power is stopped due to an emergency such as a power outage while the second control is being performed, by switching to the first control, the upper limit to which the storage battery can be charged is not limited to the third charging rate, but the upper limit to which the storage battery can be charged can be set to the second charging rate. Therefore, the storage battery can be charged to a relatively high charging rate, and if power outages occur repeatedly, the amount of power available from the storage battery at the next power outage can be increased.

[0012] Furthermore, it is preferable that the storage battery's state of charge is predicted based on the storage battery's past state of charge. In this way, the first control and the second control can be performed simply by obtaining the storage battery's state of charge, which does not complicate the configuration and reduces the amount of communication required to obtain information such as the power consumption of the load and the power generated by the fuel cell.

[0013] It is also preferable to acquire and store the power consumption of the load and the power generated by the fuel cell, and to predict the state of charge of the storage battery from the stored power consumption of the load and the power generated by the fuel cell. This allows the state of charge of the storage battery to be predicted in accordance with the actual usage of the load, thereby improving the prediction accuracy.

[0014] Furthermore, it is preferable that the storage battery and the load are electrically connected to a power generation device that uses natural energy, the storage battery is charged with at least power from the power generation device, weather forecast information including a weather forecast for the predetermined period in the location of the power generation device is acquired, the power generated by the power generation device during the predetermined period is predicted from the acquired weather forecast information, and the predicted power generated by the power generation device is used to predict the storage battery's state of charge for the predetermined period. This allows the storage battery to be charged with power generated by the power generation device, thereby reducing the amount of power purchased from the grid. Furthermore, by predicting the power generated by the power generation device during the predetermined period, the accuracy of predicting the storage battery's state of charge for the predetermined period can be improved.

[0015] Furthermore, it is preferable that the power generated by the power generation device is used by the load and the power not used by the load is used to charge the storage battery, and that the power consumption of the load for the predetermined period is predicted from the acquired weather forecast information, and the predicted power consumption of the load is used to predict the state of charge of the storage battery for the predetermined period. In this way, by predicting the power consumption of the load for the predetermined period, the state of charge of the storage battery for the predetermined period can be predicted with relatively high accuracy.

[0016] Furthermore, it is preferable to acquire and store the power generated by the fuel cell per unit time, predict the power that the fuel cell will generate per unit time during a predetermined period from the stored power generated by the fuel cell per unit time, and charge the storage battery until it reaches the second charging rate even when the condition for performing the second control is satisfied, if the predicted power generated by the fuel cell per unit time during the predetermined period will be equal to or less than a first power. According to this, by charging the storage battery to the second charging rate when the power generated by the fuel cell during the predetermined period will be equal to or less than the first power, it is possible to increase the power available for the storage battery load and reduce the amount of power purchased from the grid when the power generated by the fuel cell during the predetermined period will be equal to or less than the first power.

[0017] Furthermore, while the second control is being performed, it is preferable that the storage battery is charged only by the power generation device. This eliminates the need to purchase power from the grid to charge the storage battery, thereby reducing the amount of power purchased from the grid.

[0018] It is also preferable that the storage battery be charged only from the power generation device, which eliminates the need to purchase power from the grid to charge the storage battery, thereby reducing the amount of power purchased from the grid.

[0019] Furthermore, it is preferable to acquire weather forecast information including a weather forecast for a predetermined period in the location of the storage battery, predict a power outage of the grid power for the predetermined period from the acquired weather forecast information, and charge the storage battery until it reaches the second state of charge if a power outage of the grid power is predicted during the predicted predetermined period even if the condition for performing the second control is satisfied. According to this, by charging the storage battery until it reaches the second state of charge when there is a high possibility of a power outage during the predetermined period, it is possible to increase the power available to the load of the storage battery, suppress restrictions on use of the load, and improve user convenience.

[0020] Furthermore, it is preferable to periodically perform balance control of the charge rates of the multiple cells constituting the storage battery, and when performing the balance control, even if the second control is set, to temporarily cancel the second control and charge the storage battery until it is fully charged. This makes it possible to periodically perform balance control of the multiple cells of the storage battery that require full charging without having to take the trouble of changing the setting even if the second control is set, and to suppress variations in deterioration of the multiple cells and a decrease in the capacity of the entire storage battery.

[0021] Another aspect of the present invention is a battery management method comprising: obtaining a charging rate of a storage battery electrically connected to a load and capable of storing power from a grid power and a fuel cell; predicting the charging rate of the storage battery for a predetermined period of time; and, if the predicted charging rate of the storage battery is lower than a first charging rate, performing a first control to control the storage battery so that it can be charged to a second charging rate higher than the first charging rate; and, if the predicted charging rate of the storage battery is equal to or higher than the first charging rate, performing a second control to control the storage battery so that it can be charged to a third charging rate lower than the first charging rate.

[0022] In this mode, when it is expected that the storage battery will be used less during the predetermined period, the storage battery can be maintained at the relatively low third charging rate, thereby reducing deterioration of the storage battery. Also, when it is expected that the storage battery will be used more during the predetermined period, the storage battery can be maintained at the relatively high second charging rate, thereby increasing the power available for the storage battery load and reducing the amount of power purchased from the grid. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a block diagram showing a schematic configuration of a power supply system according to a first embodiment. [Figure 2] 1 is a functional block diagram showing the configuration of a power supply device according to a first embodiment. [Figure 3] 4 is a graph illustrating a past charging rate, a predicted charging rate, and an actual charging rate according to the first embodiment. [Figure 4] 4 is a graph illustrating a past charging rate, a predicted charging rate, and an actual charging rate according to the first embodiment. [Figure 5] 3 is a flowchart illustrating a storage battery management method according to the first embodiment. [Figure 6] 10 is a flowchart illustrating a modified example of the storage battery management method according to the first embodiment. [Figure 7] 3 is a flowchart illustrating a storage battery management method according to the first embodiment. [Figure 8] FIG. 10 is a functional block diagram showing the configuration of a power supply device according to a second embodiment. [Figure 9] 10 is a graph showing the power consumption of a load, the power generated by a fuel cell, and the charging rate of a storage battery according to the second embodiment. [Figure 10] FIG. 10 is a block diagram showing a schematic configuration of a power supply system according to a third embodiment. [Figure 11] FIG. 10 is a functional block diagram of a power supply device and a weather information server according to a third embodiment. [Figure 12] 10 is a graph showing the power consumption of a load, the power generated by a fuel cell, the power generated by a solar power generation device, and the charging rate of a storage battery according to the third embodiment. [Figure 13] 10 is a graph showing the power consumption of a load, the power generated by a fuel cell, the power generated by a solar power generation device, and the charging rate of a storage battery according to the third embodiment. [Figure 14] 10 is a flowchart illustrating a storage battery management method according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described in detail below based on embodiments.

[0025] (Embodiment 1) Fig. 1 is a block diagram showing a schematic configuration of a power supply system, and Fig. 2 is a functional block diagram showing the configuration of a power supply device 5.

[0026] As shown in FIG. 1, the power supply system 1 of this embodiment receives grid power 3 and supplies power to a load 4. The power supply system 1 includes a fuel cell 2, a power supply device 5 including a storage battery 51 and a storage battery management device 52, a power controller 6, and a distribution board 7. The distribution board 7 receives the grid power 3, and the fuel cell 2, the load 4, the power supply device 5, and the power controller 6 are electrically connected to each other via the distribution board 7.

[0027] The fuel cell 2 is a device that electrochemically converts the chemical energy of fuels such as hydrogen or methanol directly into electrical energy without converting it into heat. An example of such a fuel cell is a household fuel cell cogeneration system, commonly known as ENE-FARM (registered trademark), which generates hydrogen as fuel from city gas or LP gas, and generates electricity by reacting the hydrogen with oxygen in the air. Power generation by a fuel cell outputs stable electricity.

[0028] As the grid power 3, a commercial power source (also known as commercial electricity) is supplied from an electric utility or a grid operator that supplies commercial power.

[0029] The power controller 6 acquires the power consumption of the load 4, the power generated by the fuel cell 2, and the charging rate of the storage battery 51 of the power supply device 5, and controls the distribution board 7 to control the interconnections between the load 4, the fuel cell 2, the grid power 3, and the power supply device 5. In other words, the power controller 6 controls the connections between the load 4, the fuel cell 2, the grid power 3, and the power supply device 5, and switches the supply source when supplying power to the load 4. In this embodiment, the power controller 6 controls the fuel cell 2 to supply power to the load 4 preferentially, and the storage battery 51 to supply any power that is insufficient in the fuel cell 2. The power controller 6 also controls the grid power 3 to supply any power that is insufficient in both the fuel cell 2 and the storage battery 51. In other words, the priority order for supplying power to the load 4 by the power controller 6 is highest for the fuel cell 2, next highest for the storage battery 51, and lowest for the grid power 3. The supply source for power supplied to the load 4 is switched by the distribution board 7 under the control of the power controller 6. That is, the distribution board 7 of this embodiment has a switching function for switching the mutual connections between the load 4, the fuel cell 2, the grid power 3, and the power supply device 5.

[0030] The power controller 6 also controls the connection between the storage battery 51, the fuel cell 2, and the grid power 3, and controls switching of the power supply source for charging the storage battery 51. Of course, the functions of the power controller 6 may be provided in the storage battery management device 52 of the power supply device 5. The power controller 6, for example, supplies power from the grid power 3 to the storage battery 51 at night when the rate of the grid power 3 is low, and switches so as not to supply power from the grid power 3 to the storage battery 51 during the day when the rate of the grid power 3 is high. This allows the storage battery 51 to be charged with power from the grid power 3 at night when the rate is low. The power controller 6 also, for example, switches so as to supply power from the fuel cell 2 to the storage battery 51 at night when the power consumption of the load 4 is relatively low, and not to supply power from the fuel cell 2 to the storage battery 51 during the day when the power consumption of the load 4 is relatively high. This prevents a shortage of power from the storage battery 51 used to power the load 4 during the day, and allows effective use of the power from the fuel cell 2 during the day.

[0031] As shown in FIG. 2, the power supply device 5 includes a storage battery 51, a storage battery management device 52, a monitoring device 53, and a charge / discharge device .

[0032] The storage battery 51 is configured to be able to charge and discharge power, and is configured with a single or multiple rechargeable cells 51a. In this embodiment, lithium ion batteries are used as the cells 51a that make up the storage battery 51.

[0033] The monitoring device (CMU: Cell Monitor Unit) 53 monitors the voltage, current, temperature, and other conditions of each cell 51a of the storage battery 51 or each cell group consisting of multiple cells 51a. The monitoring device 53 also detects abnormalities in the voltage, current, temperature, and other conditions of the cells 51a and notifies the storage battery management device 52 of the occurrence of the abnormality.

[0034] The charge / discharge device 54 charges and discharges the storage battery 51 under the control of the storage battery management device 52 .

[0035] The battery management device 52 detects the charging rate of the storage battery 51. The battery management device 52 also performs overall control of each circuit of the power supply device 5, such as controlling the operation of the monitoring device 53 and the charging / discharging device 54. In other words, the battery management device 52 controls the charging and discharging of the storage battery 51 and the charging rate of the storage battery 51 by controlling the charging / discharging device 54.

[0036] Although not specifically shown, such a battery management device 52 can be realized by a central processing unit (CPU), a readable and writable memory (RAM: Random Access Memory) which is an example of a storage means, and a read-only memory (ROM: Read Only Memory) for storing various programs, etc.

[0037] The battery management device 52 includes a charging rate acquisition unit 100 , a prediction unit 101 , a control unit 102 , and a database 103 .

[0038] The charging rate acquisition unit 100 acquires the charging rate (SOC: State Of Charge) of the storage battery 51 at regular intervals, and stores the acquired charging rates in the database 103.

[0039] The prediction unit 101 predicts the charging rate of the storage battery 51 for a predetermined future period (hereinafter also referred to as the predicted charging rate) from the past charging rates stored in the database 103. The predetermined period for which the prediction unit 101 predicts the charging rate of the storage battery 51 is a preset period such as one day, several days, one week, several weeks, one month, a season (three months), or half a year, as will be described in detail later. The predicted charging rate predicted by the prediction unit 101 is the average of the charging rate over the predetermined period. The timing at which the prediction unit 101 predicts the predicted charging rate may be once a day, or every few hours if the predetermined prediction period is short, or every few days if the predetermined prediction period is long, such as seasonally. The shorter the prediction interval, the higher the accuracy of the prediction, and the longer the prediction interval, the less power consumption is required for the prediction.

[0040] In this embodiment, the prediction unit 101 predicts the charging rate of the storage battery 51 for a predetermined period from an average value of the charging rate of the storage battery 51 for a predetermined period in the past. For example, the charging rate of the storage battery 51 for a predetermined period is predicted from an average of the charging rates of the storage battery 51 measured at predetermined times during a certain period, such as the past few days, weeks, or months, which are stored in the database 103.

[0041] The prediction unit 101 may predict the charging rate of the storage battery 51 for a predetermined period from the charging rate associated with past days of the week, dates, holidays, etc. In other words, the charging rate acquisition unit 100 may store the charging rate of the storage battery 51 and the day of the week in association with each other in the database 103, and the prediction unit 101 may predict the charging rate for a predetermined period based on the charging rate stored in association with the day of the week. In other words, since the user's lifestyle, such as the amount of time they spend at home, varies depending on the day of the week, the load usage (power usage) changes depending on the day of the week. Therefore, the prediction unit 101 can improve the prediction accuracy of the charging rate of the storage battery 51 by predicting the charging rate of the storage battery 51 in association with the day of the week. In addition, the charging rate acquisition unit 100 may store the charging rate and the date in association with each other in the database 103, and the prediction unit 101 may predict the charging rate of the storage battery 51 for a predetermined period based on the charging rate of the storage battery 51 stored in association with the date. That is, the season can be determined from the date, and the amount of load 4 (power usage) used by the user, such as air conditioning, changes depending on the season. Therefore, the prediction unit 101 predicts the charge rate of the storage battery 51 in association with the date, thereby improving the prediction accuracy of the charge rate of the storage battery 51. Of course, since the day of the week can be determined from the date, the prediction accuracy of the charge rate of the storage battery 51 based on the day of the week can also be improved from the charge rate of the storage battery 51 associated with the date. Furthermore, the prediction accuracy can be improved by storing holidays in association with the charge rate of the storage battery 51 and predicting the charge rate of the storage battery 51 based on the holidays. Since holidays can also be determined from the date, the prediction accuracy of the charge rate of the storage battery 51 based on the holidays can also be improved from the charge rate of the storage battery 51 associated with the date. Such prediction of the charge rate of the storage battery 51 based on the day of the week, date, holidays, etc. can be performed using, for example, artificial intelligence (AI).

[0042] When the control unit 102 determines that the predicted charging rate predicted by the prediction unit 101 is smaller than the first charging rate, the control unit 102 performs a first control to control the charging / discharging device 54 to charge the storage battery 51 up to a second charging rate higher than the first charging rate.

[0043] In addition, when the control unit 102 determines that the predicted charging rate predicted by the prediction unit 101 is equal to or higher than the first charging rate, the control unit 102 performs a second control to control the charging / discharging device 54 so that the storage battery 51 can be charged up to a third charging rate that is lower than the first charging rate.

[0044] Here, when the control unit 102 controls the charging / discharging device 54 by the first control or the second control so that the storage battery 51 can be charged up to the second charging rate or the third charging rate, it means that the charging / discharging device 54 controls the upper limit of the charging rate of the storage battery 51 to be the second charging rate or the third charging rate.

[0045] Specific examples of the predicted charging rate of the predicting unit 101 and the first control and second control of the control unit 102 of this embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 3 and Fig. 4 are diagrams showing the past charging rate, the predicted charging rate, and the actual charging rate. In Fig. 3 and Fig. 4, the actual charging rate and its average are indicated by solid lines, and the predicted charging rate and its average are indicated by dashed dotted lines.

[0046] 3 and 4, the storage battery 51 is charged at night with power from the grid power 3. The prediction unit 101 makes a prediction in the morning, and the predetermined period for which the prediction unit 101 makes a prediction is 48 hours from midnight on the day following the day the prediction is made. Furthermore, the first charging rate is described as an SOC of 90%.

[0047] As shown in FIG. 3(a), if the state of charge has fluctuated significantly in the past, and the predicted state of charge (average) predicted by the prediction unit 101 becomes 60% based on the average state of charge over a predetermined period in the past (e.g., SOC; 60%), the predicted state of charge (SOC; 60%) will be equal to or lower than the first state of charge (SOC; 90%). Therefore, as shown in FIG. 3(b), the control unit 102 causes the charging / discharging device 54 to perform a first control that enables the storage battery 51 to be charged to a second state of charge (e.g., SOC; 100%) that is higher than the first state of charge (SOC; 90%) during the predetermined period. Here, when the predicted state of charge is lower than the first state of charge (SOC; 90%), it can be determined that the proportion of power consumed by the load 4 from the storage battery 51 during the predetermined period is high. Therefore, by performing the first control and enabling the storage battery 51 to be charged to a second charging rate (SOC; 100%) that is higher than the first charging rate (SOC; 90%), it is possible to maximize the amount of power that can be used by the load 4 of the storage battery 51 and reduce unnecessary purchase of power from the grid power 3.

[0048] Incidentally, if the predicted charging rate (for example, SOC; 60%) is equal to or lower than the first charging rate (SOC; 90%), and the control unit 102 controls the battery 51 to be charged up to a third charging rate (for example, SOC; 80%), the amount of power available to the load 4 from the battery 51 will decrease, and there may be cases where the power of the battery 51 is not enough to cover the power of the load 4, resulting in an increase in the amount of power purchased from the grid power 3.

[0049] In contrast, for example, as shown in FIG. 4(a), when the past state of charge is full charge (SOC; 100%), the predicted state of charge predicted by the prediction unit 101 from the average of the past state of charge (SOC; 100%) is full charge (SOC; 100%), which is equal to or higher than the first state of charge (SOC; 90%). Therefore, as shown in FIG. 4(b), the control unit 102 causes the charging / discharging device 54 to perform a second control that enables the storage battery 51 to be charged to a third state of charge (e.g., SOC; 80%) that is equal to or lower than the first state of charge (SOC; 90%) during a predetermined period. Here, when the predicted state of charge is equal to or higher than the first state of charge (SOC; 90%), it can be determined that the proportion of power usage of the storage battery 51 during the predetermined period is low and the storage battery 51 will be maintained in a fully charged state (SOC; 100%) or close to being fully charged for a long period. Therefore, by performing the second control to enable charging of the storage battery 51 up to a third state of charge (SOC; 80%) that is equal to or lower than the first state of charge (SOC; 90%), it is possible to suppress deterioration of the storage battery 51 and prevent a shortening of its lifespan. Note that when a lithium-ion battery is maintained at a high state of charge, such as fully charged or close to fully charged, for a long period of time, a high voltage is maintained inside the battery, which promotes chemical changes, causing deterioration and a shortening of its lifespan. Therefore, by performing the second control to enable charging of the storage battery 51 up to the third state of charge (SOC; 80%), it is possible to prevent the storage battery 51 from being maintained at a high state of charge, such as a first state of charge or close to fully charged, for a long period of time, thereby suppressing deterioration of the storage battery 51 and preventing a shortening of its lifespan.

[0050] By discharging the power of the storage battery 51 using the load 4 or the like from the time when the predicted state of charge is predicted until a predetermined period or during the predetermined period, the state of charge of the storage battery 51 decreases from full charge (SOC; 100%) to below the third state of charge (SOC; 80%). Then, when the power of the storage battery 51 is discharged and the state of charge falls below the third state of charge (SOC; 80%), the storage battery 51 can be controlled to be charged with the third state of charge as the upper limit. In other words, controlling the storage battery 51 to be chargeable up to the third state of charge by the second control means setting the upper limit of the state of charge of the storage battery 51 to the third state of charge, and setting the upper limit of the state of charge of the storage battery 51 to the third state of charge includes discharging down to the third state of charge when the state of charge of the storage battery 51 exceeds the third state of charge. When the second control is performed, or if charging is not performed for a predetermined period of time after the second control is performed, the fully charged storage battery 51 may be discharged to a third state of charge (SOC; 80%). In this case, even if it takes time to reach the third state of charge due to use with the load 4, the state of charge is immediately lowered, so that the storage battery 51 can be prevented from being maintained at or near full charge even under the second control.

[0051] Here, the storage battery management method will be described with reference to Fig. 5. Fig. 5 is a flowchart illustrating the storage battery management method.

[0052] As shown in FIG. 5, in step S1, the prediction unit 101 predicts the charging rate (predicted charging rate) of the storage battery 51 for a predetermined period.

[0053] Next, in step S2, the control unit 102 determines whether the predicted charging rate predicted by the prediction unit 101 is smaller than the first charging rate, and if the predicted charging rate is smaller than the first charging rate (step S2; Yes), in step S3, the control unit 102 performs a first control to control the charging / discharging device 54 so that the storage battery 51 can be charged at a second charging rate that is higher than the first charging rate. Such control is repeated every time the prediction unit 101 makes a prediction.

[0054] If the predicted charging rate is equal to or higher than the first charging rate in step S2 (step S2; No), in step S4, the control unit 102 performs second control to control the charging / discharging device 54 so that the storage battery 51 can be charged at a third charging rate that is equal to or lower than the first charging rate. This type of control is repeated every time the prediction unit 101 makes a prediction.

[0055] In this way, by repeatedly predicting and determining the charging rate of the storage battery 51 and performing the first control and the second control that control the upper limit of the charging rate of the storage battery 51, it is possible to suppress the deterioration of the storage battery 51 and prevent a shortening of its lifespan, and also to prevent a decrease in the power available to the load 4 of the storage battery 51 from decreasing, thereby automatically suppressing wasteful purchase of power from the grid power 3.

[0056] In this embodiment, the prediction unit 101, the control unit 102, and the database 103 are provided within the battery management device 52, but this is not particularly limited. For example, the prediction unit 101, the control unit 102, and the database 103 may be provided in a server, and the server and the battery management device 52 may be connected to each other via a network such as the Internet or a public telephone network. That is, the server may predict and determine the state of charge of the battery 51 for a predetermined period and transmit a command to the battery management device 52 to perform the first control or the second control. The battery management device 52 may then control the charge / discharge device 54 based on the command from the server, thereby controlling the state of charge of the battery 51. That is, the "battery management device" recited in the claims may be composed of only the battery management device 52 of this embodiment, or may be composed of the battery management device and a server connected to it via a network. If the prediction unit 101, control unit 102, and database 103 are provided within the battery management device 52, the battery management device 52 can make appropriate predictions by itself even in an environment where a network connection is not possible, and if the prediction unit 101, control unit 102, and database 103 are provided on a server, there is the advantage that the configuration can be simplified if the battery management device 52 has a communication function.

[0057] Furthermore, in this embodiment, the power controller 6 is provided separately from the battery management device 52, but this is not particularly limited, and the power controller 6 may be provided within the battery management device 52. In this case as well, the former allows the battery management device 52 itself to have a simple configuration, while the latter has the effect of enabling the battery management device 52 to achieve power control on its own.

[0058] Furthermore, the control unit 102 uses the power of the storage battery 51 with a fourth charging rate, which is lower than the third charging rate, as the lower limit. Here, the fourth charging rate is an arbitrary charging rate set according to the user's request. For example, the fourth charging rate can be set to ensure the minimum power required for use as an emergency power source in the event of an emergency such as a power outage. For a user who wishes to operate the load 4 for a long period of time, the fourth charging rate is set relatively high. On the other hand, for a user who wishes to actively use the power of the storage battery 51 in normal times and reduce the amount of power purchased from the grid power 3, the fourth charging rate is set relatively low in the event of an emergency, since the use of the load 4 can be short enough to save data or safely shut down the device. In other words, the storage battery 51 is operated with the fourth charging rate set as the lower limit in normal times. Furthermore, the storage battery 51 is operated with the fourth charging rate set as the lower limit in both the first control and the second control.

[0059] In the event of an emergency such as a power outage, the control unit 102 causes the load 4 to use the power of the storage battery 51 until the storage battery 51 reaches the fourth charging rate or less. When the power is restored from the power outage, if the storage battery 51 has a charging rate that is equal to or lower than the fourth charging rate, it is preferable to charge the storage battery 51 so that the charging rate reaches at least the fourth charging rate or more.

[0060] Here, a control method of the battery management device 52 will be described with reference to Fig. 6. Fig. 6 is a flowchart illustrating the battery management method. Fig. 6 shows an example in which the lower limit of the usable state of charge of the battery 51 is initially set to a fourth state of charge (for example, SOC; 30%).

[0061] First, in step S10, the control unit 102 determines whether the supply of grid power 3 has been stopped, that is, whether a power outage has occurred. If a power outage has occurred in step S10 (step S10; Yes), in step S11, the control unit 102 sets the storage battery 51 so that its power can be used up to a charging rate lower than a fourth charging rate (SOC; 30%). In the example shown in FIG. 6, the lower limit of the usable charging rate of the storage battery 51 is set to 0%. Note that the lower limit of the usable charging rate of the storage battery 51 is not limited to 0%. For example, the lower limit of the charging rate may be set to several percent for the purpose of protecting the storage battery 51. This allows the power of the storage battery 51 to be used by the load 4 until the charging rate becomes lower than the fourth charging rate (SOC; 30%). As a result, power that cannot be supplied by the fuel cell 2 during a power outage is supplied from the storage battery 51, and the charging rate of the storage battery 51 gradually decreases.

[0062] Next, in step S12, the control unit 102 determines whether the supply of grid power 3 has started, that is, whether the system has recovered from the power outage. The determination in step S12 is repeated at regular intervals until the system is restored from the power outage. If the system is restored from the power outage in step S12 (step S12; Yes), in step S13, the control unit 102 sets the usable lower limit of the state of charge of the storage battery 51 to a fourth state of charge (SOC; 30%).

[0063] Next, in step S14, the control unit 102 determines whether the charging rate of the storage battery 51 is lower than a fourth charging rate (SOC; 30%), and if the charging rate of the storage battery 51 is lower than the fourth charging rate (SOC; 30%) (step S14; Yes), in step S15 the control unit 102 charges the storage battery 51 until the charging rate becomes equal to or higher than the fourth charging rate (SOC; 30%). The charging in step S15 can be performed immediately using power from the grid power 3 or the fuel cell 2.

[0064] In step S14, if the state of charge of the storage battery 51 is equal to or higher than the fourth state of charge (SOC; 30%) (step S14; No), the storage battery 51 is used as is.

[0065] In this way, if the storage battery 51 has a charging rate lower than the fourth charging rate during an emergency such as a power outage when the supply of grid power 3 is stopped, the storage battery 51 can be immediately charged to a charging rate equal to or higher than the fourth charging rate upon recovery from the power outage, thereby preparing for the next power outage. In other words, when power outages occur repeatedly, power at the fourth charging rate can be reliably secured before the next power outage. This improves user convenience.

[0066] In step S15, the control unit 102 preferably charges the storage battery 51 at or above the fourth charging rate until the charging rate reaches the second charging rate, and more preferably charges the storage battery 51 until it is fully charged. Charging to the second charging rate or full charging when recovery from a power outage is detected only needs to be performed once upon recovery. This allows the amount of power available to the load 4 of the storage battery 51 to be increased to the second charging rate or full charging before the next power outage, even if power outages occur repeatedly, further improving user convenience.

[0067] The control shown in Fig. 6 is performed in both the first control and the second control, but for example, if an emergency such as a power outage occurs while the second control is being performed, the control may be switched to the first control. Such an example is shown in Fig. 7, which is a flowchart illustrating a storage battery management method. Fig. 7 also shows an example in which the lower limit of the usable state of charge of the storage battery 51 is initially set to a fourth state of charge (e.g., SOC; 30%).

[0068] While the second control is being performed in step S4 of Fig. 5, the control unit 102 determines in step S10 of Fig. 7 whether the supply of power from the grid power 3 has stopped, that is, whether a power outage has occurred. If a power outage has occurred in step S10 (step S10; Yes), in step S11 the control unit 102 sets the power of the storage battery 51 to a charging rate lower than a fourth charging rate (SOC; 30%), the lower limit being 0% in this embodiment.

[0069] Next, in step S16, the control unit 102 switches from the second control to the first control. As a result, the upper limit of the charging rate of the storage battery 51 is set to a second charging rate (e.g., SOC; 100%) that is higher than the third charging rate (e.g., SOC; 80%). As a result, when charging the storage battery 51 with power from the fuel cell 2 that was not used by the load 4 during a power outage, or with power from the grid power 3 or the fuel cell 2 upon recovery from the power outage, the upper limit of the charging rate can be set to the second charging rate (e.g., SOC; 100%). Therefore, since the upper limit of the charging rate of the storage battery 51 is not limited by the second control, the storage battery 51 can be easily charged at a high charging rate, which can increase the power of the storage battery 51 that can be used by the load 4 during a power outage or when power outages occur repeatedly, thereby further improving user convenience.

[0070] (Embodiment 2) Fig. 8 is a functional block diagram showing the configuration of a power supply device 5 according to a second embodiment of the present invention. Fig. 9 is a graph showing the predicted power consumption of the load 4 for a predetermined period, the power generated by the fuel cell 2, and the charging rate of the storage battery 51. Note that the same components as those in the above-mentioned embodiments are given the same reference numerals, and redundant explanations will be omitted.

[0071] 8, the power supply device 5 includes a storage battery 51, a storage battery management device 52, a monitoring device 53, and a charge / discharge device 54. The storage battery management device 52 of this embodiment includes a power information acquisition unit 104, a prediction unit 101, a control unit 102, and a database 103.

[0072] The power information acquisition unit 104 acquires the power consumption of the load 4 and the power generated by the fuel cell 2 and stores them in the database 103 .

[0073] The prediction unit 101 predicts the charging rate of the storage battery 51 for a predetermined period based on the past power consumption of the load 4 and the power generated by the fuel cell 2 stored in the database 103. Specifically, as shown in FIG. 9 , the prediction unit 101 predicts the power consumption of the load 4 for a predetermined period T, and predicts the charging rate of the storage battery 51 from the difference between the predicted power consumption of the load 4 and the power generated by the fuel cell 2. That is, during periods T1, T3, T5, and T7 when the power consumed by the load 4 can be covered by the power generated by the fuel cell 2, the power of the storage battery 51 is not used by the load 4, and the charging rate of the storage battery 51 does not decrease. Furthermore, during periods T2, T4, T6, and T8 when the power consumed by the load 4 cannot be covered by the power generated by the fuel cell 2, the power of the storage battery 51 is used by the load 4, and the charging rate of the storage battery 51 decreases. Therefore, by predicting the power consumption of the load 4, the charging rate (predicted charging rate) of the storage battery 51 for the predetermined period T can be predicted. Incidentally, the power generated by the fuel cell 2 is kept constant at a maximum power (e.g., 700 W) to effectively utilize the fuel cell 2 except in the case of an emergency stop, a maintenance stop, or a user-initiated stop. The power generated by the fuel cell 2 is an expected power. Therefore, the prediction unit 101 can easily predict the charging rate of the storage battery 51 from the expected power generated by the fuel cell 2 by predicting the power consumption of the load 4. Selective control of the first or second control is performed by determining whether the predicted charging rate is lower than the first charging rate, as in the previous embodiment. Furthermore, charging of the storage battery 51 is performed, for example, during a nighttime period T5 when the rate for the grid power 3 is low. Note that, in order to reliably and inexpensively maintain the desired charging rate of the storage battery 51, if any power generated by the fuel cell 2 is not consumed by the load 4 and is left over, the surplus power may be appropriately charged to the storage battery 51.

[0074] The control unit 102 may perform the first control or the second control directly using the power consumption of the load 4 predicted by the prediction unit 101 and the power generated by the fuel cell 2. In other words, the control unit 102 may determine whether to perform the first control or the second control by using the predicted power consumption of the load 4 and the power generated by the fuel cell 2, without directly using the predicted state of charge of the storage battery 51. In other words, predicting the state of charge of the storage battery 51 includes both direct prediction of the state of charge of the storage battery 51 and indirect prediction of the state of charge from the power consumption of the load 4. In the following description, both direct and indirect prediction of the state of charge are referred to as predicting the state of charge.

[0075] Furthermore, the power information acquiring unit 104 may store the power consumption of the load 4 and the day of the week in the database 103 in association with each other, and the prediction unit 101 may predict the power consumption of the load 4 for a predetermined period based on the power consumption of the load 4 stored in association with the day of the week, thereby predicting the charging rate of the storage battery 51. The prediction unit 101 may predict the power consumption of the load 4 in association with the day of the week and predict the charging rate of the storage battery 51, thereby improving the prediction accuracy of the charging rate of the storage battery 51. Furthermore, the power information acquiring unit 104 may store the power consumption of the load 4 and the date in association with each other in the database 103, and the prediction unit 101 may predict the power consumption of the load 4 for a predetermined period based on the power consumption of the load 4 stored in association with the date, thereby predicting the charging rate. The prediction unit 101 may predict the power consumption of the load 4 in association with the date and predict the charging rate, thereby improving the prediction accuracy of the charging rate of the storage battery 51. Of course, since the day of the week can be determined from the date, the accuracy of predicting the power consumption of the load 4 based on the day of the week can be improved from the power consumption of the load 4 associated with the date. Furthermore, the accuracy of predicting the charging rate of the storage battery 51 can be improved by correlating holidays with the power consumption of the load 4 and storing the data, and predicting the power consumption of the load 4 based on the holidays. Since holidays can also be determined from the date, the accuracy of predicting the power consumption of the load 4 based on the date can be improved from the power consumption of the load 4 associated with the date. Predicting the charging rate of the storage battery 51 based on such a prediction of the power consumption of the load 4 for a predetermined period can be performed using, for example, artificial intelligence (AI).

[0076] As in the first embodiment described above, the control unit 102 causes the charge / discharge device 54 to perform the first control or the second control based on the charging rate of the storage battery 51 for the predetermined period predicted by the prediction unit 101.

[0077] Note that, in this embodiment, the prediction unit 101 predicts the charging rate of the storage battery 51 from the power consumption of the load 4 and the power generated by the fuel cell, but this is not particularly limited thereto, and the prediction unit 101 may predict the charging rate of the storage battery 51 for a predetermined period in combination with embodiment 1. In other words, the prediction unit 101 may predict the charging rate of the storage battery 51 for a predetermined period from the past power consumption of the load 4, the power generated by the fuel cell 2, and the average charging rate of the storage battery 51 for the predetermined period. This makes it possible to predict the charging rate of the storage battery 51 using multiple elements, thereby improving the prediction accuracy.

[0078] (Embodiment 3) Fig. 10 is a block diagram showing a schematic configuration of a power supply system 1 according to a third embodiment of the present invention. Fig. 11 is a functional block diagram showing the configurations of a power supply device 5 and a weather information server 9. Figs. 12 and 13 are graphs showing the power consumption of the load 4, the power generated by the fuel cell 2, the power generated by the solar power generation device 8, and the charging rate of the storage battery 51. Note that the same components as those in the above-mentioned embodiments are assigned the same reference numerals, and redundant explanations will be omitted.

[0079] As shown in Figure 10, the power supply system 1 includes a fuel cell 2, a grid power 3, a load 4, a power supply device 5 including a storage battery 51 and a storage battery management device 52, a power controller 6, a distribution board 7, a solar power generation device 8, and a weather information server 9.

[0080] The solar power generation system 8 is an example of a power generation system that generates power using natural energy, and includes solar panels, power conditioners, etc. (not shown). The solar power generation system 8 converts sunlight into electricity using solar panels installed on the roof or rooftop of a house. The amount of power generated by the solar power generation system varies depending on the amount of solar radiation and the power generation efficiency of the solar panels.

[0081] Note that the power generation device using natural energy is not limited to the solar power generation device 8, and examples thereof include wind power generation devices and hydroelectric power generation devices. Incidentally, a wind power generation device uses the power of wind to turn a windmill, and converts the rotational motion of the windmill into electricity via a generator. The amount of electricity generated by a wind power generation device varies depending on the strength of the wind (wind speed). Also, a hydroelectric power generation device uses the power of water to turn a watermill, and converts the rotational motion of the watermill into electricity via a generator. The amount of electricity generated by a hydroelectric power generation device varies depending on the amount of water (rainfall).

[0082] Moreover, the solar power generation device 8 is electrically connected to the storage battery 51 via the distribution board 7. In this embodiment, the solar power generation device 8 is also electrically connected to the load 4 via the distribution board 7.

[0083] The power generated by the solar power generation device 8 is used under the control of the power controller 6 to supply to the load 4, charge the storage battery 51, sell to the grid power 3, and so on. The supply to the load 4, charging to the storage battery 51, and selling can be performed independently or in combination. Examples of combinations include the following: The power generated by the solar power generation device 8 is used by the load 4, and surplus power not used by the load 4 is charged to the storage battery 51. Furthermore, the power generated by the solar power generation device 8 is used by the load 4, and surplus power not used by the load 4 is sold. The power generated by the solar power generation device 8 is used to charge the storage battery 51, and surplus power not used to charge the storage battery 51 is sold. Furthermore, the power generated by the solar power generation device 8 is used by the load 4, and surplus power not used to charge the storage battery 51 is used to sell. If the power generated by the solar power generation device 8 is not used to charge the storage battery 51, the storage battery 51 may be charged with power from the grid power 3 at night or other times when the charge is low.

[0084] The use of the power generated by the solar power generation device 8 is controlled by the power controller 6. That is, the use of the power generated by the solar power generation device 8 is determined by previously setting which of the above-mentioned combination examples to control in the power controller 6. Furthermore, the use of the power generated by the solar power generation device 8 may be changed according to the user's request, for example, to a power selling mode that prioritizes power selling, or a low power purchasing mode that reduces power purchasing. In this embodiment, the power controller 6 controls the power generated by the solar power generation device 8 to be used by the load 4, the power not used by the load 4 to be used to charge the storage battery 51, and the power not used in charging the storage battery 51 to be sold.

[0085] The weather information server 9 is a weather forecast supply means that provides weather forecast information, which is information including weather forecasts for location information such as by address or region. Although not specifically shown, such weather information server 9 can be realized by a central processing unit (CPU), a readable and writable memory (RAM: Random Access Memory), which is an example of storage means, and a read-only memory (ROM: Read Only Memory) for storing various programs. The weather forecast information provided by the weather information server 9 may include a weather forecast and a temperature forecast. The weather information server 9 is mutually connected to the battery management device 52 of the power supply device 5 via a network N. The network N may be the Internet, a public telephone line network, or the like.

[0086] The other components such as the fuel cell 2 are the same as those in the above-described embodiment, and therefore a duplicated description will be omitted.

[0087] The power supply device 5 includes a storage battery 51, a storage battery management device 52, and a monitoring device 53 and a charge / discharge device 54, as shown in FIG.

[0088] As shown in FIG. 11, the battery management device 52 includes a power information acquisition unit 104, a prediction unit 101, a control unit 102, a database 103, and a weather information acquisition unit 105.

[0089] The weather information acquisition unit 105 acquires weather forecast information corresponding to location information of the location, such as the address and region, of the solar power generation device 8 from the weather information server 9. The weather information acquisition unit 105 identifies the location of the solar power generation device 8 and acquires weather forecast information for the location of the solar power generation device 8 at regular intervals, such as every hour or every two hours, or throughout the day. The weather forecast information acquired by the weather information acquisition unit 105 from the weather information server 9 may be acquired when the prediction unit 101 predicts the charge rate (predicted charge rate) of the storage battery 51 for a predetermined period, or may be acquired periodically at regular intervals. The weather forecast information acquired by the weather information acquisition unit 105 includes at least a weather forecast for a predetermined period for which the prediction unit 101 predicts the charge rate of the storage battery 51. For example, if the predetermined period for which the prediction unit 101 predicts the charge rate of the storage battery 51 is 24 hours for the next day, the weather forecast information acquired by the weather information acquisition unit may include at least the 24 hours for the next day.

[0090] As in the second embodiment described above, the power information acquiring unit 104 acquires the power consumption of the load 4 and the power generated by the fuel cell 2. The power information acquiring unit 104 also acquires the power generated by the solar power generation device 8 and stores these in the database 103.

[0091] The prediction unit 101 predicts the power to be generated by the solar power generation device 8 for a predetermined period from the weather forecast information acquired by the weather information acquisition unit 105. The power to be generated by the solar power generation device 8 varies depending on the amount of solar radiation based on the weather and the power generation efficiency of the solar power generation device 8, as described above. For this reason, the prediction unit 101 predicts the power to be generated by the solar power generation device 8 at regular time intervals during the predetermined period T, as shown in Figs. 12 and 13 , based on the weather forecast information including the weather forecast acquired by the weather information acquisition unit 105 and the power generation efficiency of the solar power generation device 8. Note that the power to be generated by the solar power generation device 8 varies depending on the deterioration of power generation efficiency over time due to dirt on the solar panels, the angle and direction of the solar panels, the season indicating the position of the sun and the hours of sunshine, and the weather (weather forecast) indicating the amount of solar radiation. For this reason, it is preferable that the prediction unit 101 predicts the power to be generated by the solar power generation device 8 by performing a weighting calculation based on the rate of power generation decline due to aging of the solar panels, the angle and direction of the solar panels, the season indicating the position of the sun and the duration of sunlight, in addition to the weather forecast information and the power generation efficiency of the solar power generation device 8. In this way, the prediction unit 101 can improve the prediction accuracy of the power to be generated by predicting the power to be generated by the solar power generation device 8 based on the rate of power generation decline due to aging of the solar panels, the angle and direction of the solar panels, the season indicating the position of the sun and the duration of sunlight, in addition to the weather forecast information and the power generation efficiency of the solar power generation device 8. Note that information for predicting the power to be generated by the solar power generation device 8 may be stored in the database 103. It is also more preferable that the weather forecast information acquired by the weather information acquisition unit 105 for a specific date or season and the power generated by the solar power generation device 8 acquired by the power information acquisition unit 104 are associated with each other and stored in the database 103 as power generation results, and the power to be generated by the solar power generation device 8 based on the weather forecast information for each fixed time period over a predetermined period is predicted based on the accumulated power generation results. In this way, the prediction unit 101 can further improve the prediction accuracy by predicting the power generated by the solar power generation device 8 from the power generation record of the solar power generation device 8 based on the weather forecast.

[0092] In addition, when a wind power generation device is used as a power generation device using natural energy, the weather information acquisition unit 105 acquires a weather forecast including information on wind speed and wind direction from the weather information server 9, and the prediction unit 101 predicts the amount of power generated by the wind power generation device for a specified period based on the information on wind speed and wind direction.

[0093] Similarly, when a hydroelectric power generation device is used as the power generation device using natural energy, the weather information acquisition unit 105 acquires a weather forecast including rainfall from the weather information server 9, and the prediction unit 101 predicts the amount of power generated by the hydroelectric power generation device for a predetermined period based on the rainfall. In any case, for a power generation device using natural energy, the prediction unit 101 can predict the power generated by the power generation device for a predetermined period from the weather forecast.

[0094] Furthermore, similar to the second embodiment described above, the prediction unit 101 predicts the power consumption of the load 4 for a predetermined period T, and predicts the charging rate of the storage battery 51 for the predetermined period T based on the predicted power consumption of the load 4, the power generated by the fuel cell 2, and the predicted power generated by the solar power generation device 8, as shown in FIG. 12.

[0095] 12, during period T11 of the predetermined period T, the predicted power consumption of the load 4 is lower than the power generated by the fuel cell 2, and therefore the power of the storage battery 51 is not used. During period T12, the predicted power consumption of the load 4 is higher than the sum of the power generated by the fuel cell 2 and the predicted power generated by the solar power generation device 8, and therefore the shortfall in the power consumed by the load 4 is supplied from the storage battery 51. Therefore, during period T12, the charging rate of the storage battery 51 gradually decreases.

[0096] During period T13, the predicted power consumption of load 4 is lower than the sum of the power generated by fuel cell 2 and the predicted power generated by solar power generation device 8, and therefore the power of storage battery 51 is not used. Also, during this period T13, storage battery 51 is charged with the power generated by solar power generation device 8 that is not used by load 4. Therefore, during period T13, the charging rate of storage battery 51 gradually increases.

[0097] During period T14, the predicted power consumption of load 4 is lower than the sum of the power generated by fuel cell 2 and the predicted power generated by solar power generation device 8, and therefore storage battery 51 is charged with the power generated by solar power generation device 8 that is not used by load 4. Therefore, during period T14, the charging rate of storage battery 51 gradually increases.

[0098] During period T15, the predicted power consumption of load 4 is lower than the power generated by fuel cell 2, so the power generated by solar power generation device 8 is used to charge storage battery 51. As a result, the charging rate of storage battery 51 gradually increases. Note that during period T15, the charging rate of storage battery 51 reaches 100% midway, and the surplus power generated by solar power generation device 8 that is not charged into storage battery 51 is sold.

[0099] During period T16, the predicted power consumption of the load 4 is higher than the sum of the power generated by the fuel cell 2 and the predicted power generated by the solar power generation device 8, and therefore the shortfall in the power consumption of the load 4 is supplied from the storage battery 51. Therefore, during period T16, the charging rate of the storage battery 51 gradually decreases.

[0100] By similar prediction, the power of the storage battery 51 is not used in period T17, and is used in period T18. Furthermore, the power of the storage battery 51 is not used in period T19, and is charged with power generated by the solar power generation device 8 in period 20. Furthermore, the power of the storage battery 51 is not used in period 21, is used in period 22, and is not used in period 23.

[0101] By predicting the power consumption of the load 4 and the power generated by the solar power generation device 8 for such a predetermined period T, and predicting the charging rate of the storage battery 51 from these predicted powers, it is possible to predict with high accuracy the average charging rate of the storage battery 51 for the predetermined period T.

[0102] Based on this prediction of the state of charge of the storage battery 51 for the predetermined period T, the control unit 102 performs the first control or the second control, as in the above-described embodiment. That is, as shown in Fig. 12, when the predicted state of charge of the storage battery 51 for the predetermined period T is lower than a first state of charge (e.g., SOC; 90%), the control unit 102 performs control (first control) so that the storage battery 51 can be charged to a second state of charge (e.g., SOC; 100%) that is higher than the first state of charge (e.g., SOC; 90%). As a result, when the power consumption of the load 4 is greater than the sum of the power generated by the fuel cell 2 and the power generated by the solar power generation device 8, the power consumption of the load 4 can be covered by the power of the storage battery 51, improving user convenience and reducing the amount of power purchased from the grid power 3.

[0103] 13, the predicted power consumption of the load 4 is equal to or less than the power generated by the fuel cell 2, and therefore the predicted power generated by the solar power generation device 8 is used to charge the storage battery 51. However, in the example shown in FIG. 13, the storage battery 51 is at a state of charge of 100% (fully charged), and therefore the average state of charge of the storage battery 51 over the predetermined period T is predicted to be SOC; 100%. Therefore, the control unit 102 performs the second control over the predetermined period T to control the storage battery 51 so that it can be charged up to a third state of charge (for example, SOC; 80%) over the predetermined period T. This prevents the storage battery 51 from being maintained at a state of charge that is fully charged or close to full charge for a long period of time, thereby suppressing deterioration of the storage battery 51 and reducing a shortening of the life of the storage battery 51. When the second control is performed, or when the storage battery 51 is maintained at a high state of charge above the first state of charge without being discharged for a predetermined period of time after the second control is performed, the storage battery 51 may be discharged to a third state of charge (SOC; 80%). In this case, even if it takes time to reach the third state of charge due to use with the load 4, the state of charge is immediately lowered, so that the storage battery 51 can be prevented from being maintained at or near full charge even under the second control.

[0104] Note that the prediction unit 101 may predict the power consumption of the load 4 for a predetermined period using a weather forecast for the predetermined period acquired by the weather information acquisition unit 105. For example, if the forecast predicts high temperatures and humidity in the summer, it can be predicted that the power consumption of the load 4 will be high because air conditioning will be used more frequently. On the other hand, if the forecast predicts low temperatures in the summer, it can be predicted that the power consumption of the load 4 will be low because air conditioning will not be used much. By predicting the power consumption of the load 4 for a predetermined period using a weather forecast in this way, the prediction accuracy of the power consumption of the load 4 for the predetermined period can be improved, and the prediction accuracy of the charging rate of the storage battery 51 can be further improved.

[0105] Furthermore, when the control unit 102 is performing the second control, that is, when the control unit 102 is performing control so that the storage battery 51 can be charged to a third storage rate (for example, SOC; 80%), the storage battery 51 may be charged only with the power generated by the solar power generation device 8. In other words, when the second control is being performed, the power consumed by the load 4 is low, so the storage battery 51 is charged only with the power generated by the solar power generation device 8, and even if the storage battery 51 does not reach the third storage rate, it is unlikely that the power will be insufficient to cover the power consumed by the load 4. Therefore, by charging the storage battery 51 only with the power generated by the solar power generation device 8 while the second control is being performed, it is no longer necessary to purchase power from the grid power 3 to make up for the insufficient power required to charge the storage battery 51, and it is possible to reduce the amount of power purchased.

[0106] Furthermore, for example, when the control unit 102 is performing the first control, the storage battery 51 may be charged during the day with the power generated by the solar power generation device 8, and if the storage battery 51 has not reached the second state of charge (e.g., SOC; 100%) under the first control using only the power generated by the solar power generation device 8, the storage battery 51 may be charged at night using power from the grid power 3 until the second state of charge is reached. This allows the power of the storage battery 51 used by the load 4 to be increased, and the amount of power purchased during the day when the grid power 3 charges a high fee to be reduced. Of course, even during the first control, if the storage battery 51 is charged only with the power generated by the solar power generation device 8, as in the second control, the amount of power purchased from the grid power 3 can be reduced.

[0107] The power information acquisition unit 104 may also acquire the power generated by the fuel cell 2 per unit time and store it in the database 103, and the prediction unit 101 may predict the power generated by the fuel cell 2 per unit time for a predetermined period from the stored data on the power generated by the fuel cell 2. Here, the fuel cell 2 is shut down for maintenance for 12 to 24 hours if it has been used continuously for 26 days or more. For this reason, in preparation for a high possibility of a power outage due to a typhoon or other such event, the user may shut down the fuel cell 2 in advance to prevent the fuel cell 2 from being shut down for maintenance on the day of the typhoon. Therefore, by storing the power generated by the fuel cell 2 per unit time in the database 103, the power information acquisition unit 104 can store information on the date and time of fuel cell 2 maintenance or intentional user shutdown.

[0108] Then, based on the past fuel cell 2 shutdown dates and shutdown times stored in the database 103, the prediction unit 101 can predict the date and time when the fuel cell 2 will be shut down for maintenance 26 days after the past shutdown date.

[0109] Therefore, when the prediction unit 101 predicts that the power generated per unit time by the fuel cell 2 in a predetermined period will be a first power or less (for example, 0 kWh or less), the control unit 102 controls the charge / discharge device 54 to charge the storage battery 51 until the storage battery 51 reaches a second charging rate (for example, SOC; 100%). When the power generated per unit time by the fuel cell 2 in a predetermined period will be the first power or less, it is predicted that the power generated by the fuel cell 2 will no longer be enough to cover the power consumed by the load 4, and the power of the storage battery 51 or the grid power 3 will be used. Therefore, even when the control unit 102 is performing the second control of the storage battery 51, that is, controlling the storage battery 51 so that the charging rate is a third charging rate (e.g., SOC; 80), if the control unit 102 predicts that the power generated per unit time by the fuel cell 2 during a predetermined period will be equal to or lower than the first power (e.g., 0 kWh or lower), the control unit 102 charges the storage battery 51 until the charging rate of the storage battery 51 reaches a second charging rate (e.g., SOC; 100%) before the predetermined period. Alternatively, if the predetermined period is long, the control unit 102 charges the storage battery 51 to the second charging rate by the date and time when the power generated per unit time by the fuel cell 2 will be equal to or lower than the first power. The power used to charge the storage battery 51 at this time may be power generated by the solar power generation device 8, power from the grid power 3, or power from the fuel cell 2. The control unit 102 or the power controller 6 may control the storage battery 51 so that the charging rate is equal to the second charging rate using power from the solar power generation device 8, the grid power 3, and the fuel cell 2 before the predetermined period. In other words, even when the control unit 102 is performing the second control to set the upper limit of the storage battery 51's storage rate to the third storage rate (SOC; 80%), if the prediction unit 101 predicts that the power per unit time of the fuel cell 2 will be equal to or less than the first power during the predetermined period, the control unit 102 charges the storage battery 51 until the storage battery 51's storage rate exceeds the third storage rate (SOC; 80%) and reaches the second storage rate (for example, SOC; 100%) before the predetermined period ends. As a result, even if the power generated by the fuel cell 2 during the predetermined period is equal to or less than the first power, the amount of power consumed by the load 4 that can be supplied by the storage battery 51 can be increased, and the amount of power purchased from the grid power 3 can be reduced.Of course, even while performing the first control, if the control unit 102 predicts that the power generated per unit time by the fuel cell 2 during a predetermined period will be equal to or less than the first power (e.g., equal to or less than 0 kWh), the control unit 102 charges the storage battery 51 until the charging rate of the storage battery 51 reaches a second charging rate (e.g., SOC; 100%) before the predetermined period begins or before the power generated by the fuel cell 2 falls below the first power.

[0110] Here, a control method of the battery management device 52 will be described with reference to Fig. 14. Fig. 14 is a flowchart illustrating the battery management method. Note that the first power is set to 0 kWh. Furthermore, the same steps as in Fig. 5 are assigned the same reference numerals, and duplicated explanations will be omitted.

[0111] In step S1, the prediction unit 101 predicts the power consumption of the load 4, the power generated by the fuel cell 2, and the power generated by the solar power generation device 8 for a predetermined period, and predicts the charging rate of the storage battery 51.

[0112] In step S20, the control unit 102 determines whether the predetermined period predicted by the prediction unit 101 includes a period in which the power generated per unit time by the fuel cell 2 becomes equal to or less than the first power. If, in step S20, the predicted predetermined period includes a period in which the power generated per unit time by the fuel cell 2 becomes equal to or less than the first power (step S20; Yes), in step S21, the storage battery 51 is charged to a second charging rate. The power used to charge the storage battery 51 at this time is, for example, power generated by the solar power generation device 8, power from the grid power 3, and power from the fuel cell 2. Furthermore, in step S21, the storage battery 51 is charged to the second charging rate until the predicted predetermined period arrives. Therefore, for example, even if the period from the predicted timing to the predetermined period is daytime and this period satisfies the condition for the second control, the storage battery 51 may be charged to the second charging rate using the power generated by the solar power generation device 8. Furthermore, for example, if there is a nighttime period during the period from the predicted timing to a predetermined period when the rate for the grid power 3 is low, the storage battery 51 may be charged with power from the grid power 3 during that nighttime period.

[0113] Steps S20 and S21 are repeated for each period predicted by the prediction unit 101.

[0114] If the power generated by the fuel cell 2 during the predetermined period predicted by the prediction unit 101 in step S1 does not become equal to or less than the first power (step S20; No), step S2, step S3 or step S4 shown in Figure 5 described above may be performed to perform the first control or the second control.

[0115] 14 , if the prediction unit 101 predicts that the power per unit time of the fuel cell 2 will be equal to or less than the first power during a predetermined period while the first control and the second control are being performed, the control unit 102 charges the storage battery 51 until the charging rate reaches the second charging rate. In other words, while the first control is being performed, the power of the storage battery 51 is used by the load 4, so the charging rate of the storage battery 51 is not always equal to the second charging rate. Therefore, even when the first control is being performed, if the prediction unit 101 predicts that the power per unit time of the fuel cell 2 will be equal to or less than the first power during a predetermined period, the control unit 102 charges the storage battery 51 until the charging rate reaches the second charging rate, thereby increasing the power that can be used by the load 4 from the storage battery 51 during the predetermined period and reducing the amount of power purchased from the grid power 3.

[0116] Furthermore, for example, when the predetermined period predicted by the prediction unit 101 is relatively long, for example, when the day predicted by the prediction unit 101 is the first day and the predetermined period predicted by the prediction unit 101 is 25 days from the day after the predicted first day, and when the power generated per unit time by the fuel cell 2 during the 25 days includes being equal to or less than the first power, the control unit 102 may perform control as follows. For example, even if the charging rate of the storage battery 51 predicted by the prediction unit 101 for the 25 days, that is, the predicted charging rate which is the average of the predicted charging rates, satisfies the condition for performing the second control, the control unit 102 may charge the storage battery 51 until it reaches the second charging rate. Furthermore, even if the charging rate of the storage battery 51 predicted by the prediction unit 101 for the 25 days satisfies the condition for performing the second control, the control unit 102 may perform the first control so that the storage battery 51 is charged to the second charging rate. In other words, the condition for performing the second control is satisfied when it is predicted that the storage battery 51 will be maintained at the second charging rate or a charging rate close to the second charging rate, and therefore the first control is performed to control the storage battery 51 so that it can be charged up to the second charging rate, thereby enabling the storage battery 51 to be charged up to the second charging rate. Furthermore, if the predetermined period is as long as 25 days, the control unit 102 may charge the storage battery 51 up to the second charging rate just before the power generated by the fuel cell 2 becomes equal to or less than the first power, even when the condition for performing the second control is satisfied.

[0117] Furthermore, if the predetermined period predicted by the prediction unit 101 is short, it is possible to predict whether the power generated by the fuel cell 2 will be equal to or less than the first power due to maintenance of the fuel cell 2 or a user-initiated shutdown, even after the predetermined period has elapsed. Therefore, if the predetermined period is short, for example, the day on which the prediction unit 101 makes the prediction is the first day, the predetermined period predicted by the prediction unit 101 is the day after the predicted day (the first day), and the prediction unit 101 also predicts the day after (the third day) on the second day, and if the power generated by the fuel cell 2 on the third day will be equal to or less than the first power, the control unit 102 may perform control as follows. For example, when making a prediction on the first day, the prediction unit 101 predicts whether the power generated by the fuel cell 2 on the third day will be equal to or less than the first power. Even if the weather forecast predicts that the second day will be sunny, satisfying the conditions for performing the second control on the second day, the control unit 102 performs the first control on the second day because it predicts that the power generated by the fuel cell 2 on the third day will be equal to or less than the first power. As a result, the control unit 102 controls the storage battery 51 so that its charging rate is as close to the second charging rate as possible on the second day. If the prediction unit predicts, when making a prediction on the first day, that it will rain on the second day of the predetermined period and that the power generated by the fuel cell 2 will be equal to or less than the first power on the third day after the predetermined period, the prediction unit charges the storage battery 51 so that it will be at the second charging rate by the second day of the predetermined period. In this case, the storage battery 51 may be charged to the second charging rate by charging it by the solar power generation device 8 on a sunny day on the first day, or the shortfall may be made up by charging it with power from the grid power 3 at night when the rate is lower.

[0118] Furthermore, in the above example, the first power is described as 0 kWh, but this is not particularly limited to this, and it is possible that the power generated by the fuel cell 2 will be half or one-third of the normal power due to a malfunction, restrictions on the fuel supply, etc. If it can be predicted that the power generated by such a fuel cell 2 will be the first power, which is lower than the power during normal use, then that power can be determined to be the first power.

[0119] Furthermore, the prediction unit 101 may predict a power outage of the grid power 3 based on a weather forecast for a predetermined period acquired by the weather information acquisition unit 105. For example, if the weather forecast for the predetermined period indicates a high possibility of a power outage due to a typhoon, heavy rain, strong winds, lightning, or the like, or a power outage due to a drop in temperature resulting in an increase in power demand but a power supply shortage, i.e., a so-called power outage caused by a tight power supply and demand balance, the prediction unit 101 predicts that the grid power 3 will experience a power outage during the predetermined period. Even if the storage rate of the storage battery 51 predicted by the prediction unit 101 satisfies the condition for the second control, if the prediction unit 101 predicts that there is a high possibility of a power outage of the grid power 3 during the predetermined period, it is preferable that the control unit 102 charges the storage battery 51 until it reaches a second storage rate (e.g., SOC; 100%). Here, the control unit 102 charges the storage battery 51 to the second storage rate until the predicted predetermined period arrives. Therefore, for example, even if the period from the predicted timing to the predetermined period is daytime and this period satisfies the condition for the second control, the storage battery 51 may be charged to the second charging rate using the power generated by the solar power generation device 8. Also, for example, if there is a nighttime period during the period from the predicted timing to the predetermined period when the rate for the grid power 3 is low, the storage battery 51 may be charged using power from the grid power 3 during that nighttime period.

[0120] In this way, if the weather forecast for a predetermined period indicates that there is a high possibility of a power outage in the grid power 3 during that period, the storage battery 51 is charged in advance to the second charge rate (for example, SOC; 100%), so that when a power outage in the grid power 3 occurs during that period, the power supplied from the storage battery 51 to the load 4 can be increased. Therefore, it is possible to prevent the user from being restricted in using the load 4 during a power outage in the grid power 3, thereby improving convenience.

[0121] (Other embodiments) Although the embodiments of the present invention have been described above, the basic configuration of the present invention is not limited to those described above.

[0122] The charging rates of the multiple cells 51a constituting the storage battery 51 gradually vary. For this reason, the storage battery management device 52 performs balance control to equalize the charging rates of the multiple cells 51a of the storage battery 51. Here, the balance control of the storage battery 51 is performed by fully charging the storage battery 51. The balance control of the storage battery management device 52 is performed at regular intervals. For this reason, when the first control is being performed during the regular interval of the balance control of the storage battery 51, if the second charging rate is set to full charge (SOC; 100%), the storage battery management device 52 continues to perform the balance control. Furthermore, even if the second control is being performed during the regular interval of the balance control of the storage battery 51, it is preferable that the storage battery management device 52 temporarily cancels the second control and performs the balance control after fully charging the storage battery 51. In this way, the balance control of the cells 51a can be performed to prevent a decrease in the chargeable / dischargeable electrical capacity of the storage battery 51.

[0123] In the above-described embodiments, the first charging rate is set to 90% SOC, the second charging rate is set to 100% SOC, and the third charging rate is set to 80% SOC, but this is not a limitation. For example, the first charging rate is preferably set to a range of 70% to 90% SOC, the second charging rate is preferably set to a range of 80% to 100% SOC, and the third charging rate is preferably set to a range of 60% to 90% SOC. By setting the first, second, and third charging rates within the above ranges, the first control can ensure that the storage battery 51 has enough power to power the load 4, while the second control can prevent the storage battery 51 from deteriorating.

[0124] In addition to storing the charging rate and the date in association with each other in the database 103, in order to improve the accuracy of prediction, information on the temperature (minimum temperature, maximum temperature, daytime temperature, etc.) and weather on the target date may also be stored in association with each other, and predictions may be made based on information on the charging rate that matches the temperature and weather of the target prediction period from among the stored past charging rates, taking into account not only the charging rate and the date, but also the temperature and weather (information on the day of the week may also be taken into account).

[0125] In each of the above-described embodiments, a configuration in which a lithium ion battery is used as the cell 51a constituting the storage battery 51 is exemplified. However, the cell 51a is not limited to a lithium ion battery as long as it has the same characteristics as a lithium ion battery and the problem of the present invention occurs. [Explanation of symbols]

[0126] T...predetermined period, T1 to T23...period, 1...power supply system, 2...fuel cell, 3...grid power, 4...load, 5...power supply device, 6...power controller, 7...distribution board, 8...photovoltaic power generation device, 9...weather information server, 51...storage battery, 51a...cell, 52...storage battery management device, 53...monitoring device, 54...charging / discharging device, 100...charging rate acquisition unit, 101...prediction unit, 102...control unit, 103...database, 104...power information acquisition unit, 105...weather information acquisition unit

Claims

1. A storage battery is electrically connected to the load and is capable of storing power from the grid power and the fuel cell, and a charging rate of the storage battery is obtained from the storage battery; a first control that predicts a charging rate of the storage battery for a predetermined period, and, when the predicted charging rate of the storage battery is lower than a first charging rate, controls the storage battery so that it can be charged to a second charging rate higher than the first charging rate; and a second control that controls the storage battery so that it can be charged to a third charging rate that is less than or equal to the first charging rate when the predicted charging rate of the storage battery is greater than or equal to the first charging rate.

2. 2. The battery management device according to claim 1, wherein the storage battery is used with a fourth charging rate lower than the third charging rate as a lower limit value.

3. 3. The battery management device according to claim 2, wherein when the charging rate of the storage battery becomes lower than the fourth charging rate, the storage battery is charged so that the charging rate exceeds at least the fourth charging rate.

4. The battery management device according to any one of claims 1 to 3, characterized in that if the supply of the grid power is stopped while the second control is being performed, the battery management device switches to the first control.

5. 5. The battery management device according to claim 1, wherein the prediction of the charging rate of the storage battery is performed based on a past charging rate of the storage battery.

6. Acquiring and storing the power consumed by the load and the power generated by the fuel cell; A battery management device as described in any one of claims 1 to 5, characterized in that the charging rate of the storage battery is predicted from the accumulated power consumption of the load and the power generated by the fuel cell.

7. the storage battery and the load are electrically connected to a power generation device that uses natural energy, and the storage battery is charged with at least the power from the power generation device; acquire weather forecast information including a weather forecast for the predetermined period in the location of the power generation device; predicting the power to be generated by the power generation device during the predetermined period based on the acquired weather forecast information; 7. The battery management device according to claim 1, wherein the predicted power generated by the power generation device is used to predict the charging rate of the storage battery for the predetermined period.

8. The power generated by the power generation device is used by the load, and the power not used by the load is used to charge the storage battery, predicting the power consumption of the load for the predetermined period from the acquired weather forecast information; 8. The battery management device according to claim 7, wherein the predicted power consumption of the load is used to predict the state of charge of the battery for the predetermined period.

9. Acquiring and storing the power generated per unit time by the fuel cell; predicting the power generated by the fuel cell per unit time for a predetermined period from the accumulated power generated by the fuel cell per unit time; A battery management device as described in any one of claims 1 to 8, characterized in that even if the conditions for performing the second control are met, if the predicted power generated per unit time by the fuel cell during a predetermined period of time is equal to or less than a first power, the battery is charged until it reaches the second charge rate.

10. 9. The battery management device according to claim 7, wherein while the second control is being performed, the battery is charged only by the power generation device.

11. 9. The battery management device according to claim 7, wherein the battery is charged only from the power generation device.

12. acquiring weather forecast information including a weather forecast for a predetermined period in a location of the storage battery; predicting a power outage of the grid power for the predetermined period based on the acquired weather forecast information; The battery management device according to any one of claims 1 to 11, characterized in that even if the conditions for performing the second control are met, if a power outage of the grid power is predicted during the predicted predetermined period, the battery is charged until it reaches the second charge rate.

13. performing balance control of the charge rates of the plurality of cells constituting the storage battery at a constant cycle; The battery management device according to any one of claims 1 to 12, characterized in that when the balance control is performed, even if the second control is set, the second control is temporarily released and the storage battery is charged until it is fully charged.

14. A storage battery is electrically connected to the load and is capable of storing power from the grid power and the fuel cell, and a charging rate of the storage battery is obtained from the storage battery; a first control that predicts a charging rate of the storage battery for a predetermined period, and, when the predicted charging rate of the storage battery is lower than a first charging rate, controls the storage battery so that it can be charged to a second charging rate higher than the first charging rate; and a second control that controls the storage battery so that it can be charged to a third charging rate that is lower than the first charging rate when the predicted charging rate of the storage battery is higher than the first charging rate.

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