Power system and charging control method

Abstract

To provide a power system and a charging control method that can perform more appropriate charging control according to the status of the energy storage device within the power system. [Solution] The power supply system of the embodiment is a power supply system equipped with a plurality of detachable energy storage devices, comprising: a charging unit that charges the energy storage devices from an external power source; a detection unit that detects the total remaining power of the remaining energy storage devices attached to the power supply system after at least one of the plurality of energy storage devices has been removed from the power supply system; and a charging control unit that causes the charging unit to charge the remaining energy storage devices when the remaining power is less than a predetermined amount.

Description

Technical Field

[0001] The present invention relates to a power supply system and a charging control method.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development on charging and discharging in mobility equipped with secondary batteries that contribute to energy efficiency has been carried out. In this regard, a charging facility electrically connected to a power-driven device driven by commercial power supply, a charging unit for charging a detachable battery provided by exchanging a detachable battery that supplies driving power to an electric vehicle, and a control unit for controlling power supply from the detachable battery attached to the charging unit to the power-driven device when the power supply from the commercial power supply to the power-driven device is interrupted are known (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in the technology for charging and supplying power to mobility devices equipped with secondary batteries, there are cases where a removable energy storage device (e.g., a removable battery) installed in a household (stationary) power system is mounted on the mobility device and used. Furthermore, in household power systems, a certain amount of power (remaining charge) is sometimes maintained in advance to ensure that power can be used during power outages caused by disasters, or to save on electricity costs by storing power during off-peak hours when electricity rates are low and using it during off-peak hours when rates are high. However, since the remaining power in the system changes due to the removal of removable batteries, etc., control is needed to respond to these changes, but sufficient consideration has not been given to the above control, so there is room for further consideration.

[0005] This application was made in view of these circumstances, and one of its objectives is to provide a power supply system and a charging control method that can perform more appropriate charging control according to the status of the energy storage device within the power supply system. This will ultimately contribute to energy efficiency. [Means for solving the problem]

[0006] The power supply system and charging control method according to this invention employ the following configuration. (1) A power supply system according to one aspect of the present invention is a power supply system equipped with a plurality of detachable energy storage devices, comprising: a charging unit that charges the energy storage devices from an external power source; a detection unit that detects the total remaining power of the remaining energy storage devices attached to the power supply system after at least one of the plurality of energy storage devices has been removed from the power supply system; and a charging control unit that causes the charging unit to charge the remaining energy storage devices when the remaining power is less than a predetermined amount.

[0007] (2) In the embodiment of (1) above, the charging control unit causes the charging unit to charge the remaining power storage devices attached to the power system so that the total remaining power of the remaining power storage devices attached to the power system is equal to or greater than the predetermined remaining amount when at least one of the plurality of power storage devices is taken out of the power system.

[0008] (3) In the embodiment of (1) above, the charging control unit charges the remaining energy storage devices after a predetermined time has elapsed since at least one of the plurality of energy storage devices was disconnected from the power supply system.

[0009] (4) In the embodiment of (3) above, the predetermined time is set based on the elapsed time from when the energy storage device is removed until it is returned.

[0010] (5) In the embodiment of (3) above, the predetermined time is set based on the maximum output or rated output of the energy storage device.

[0011] (6) In the embodiment of (3) above, the predetermined time is set based on the usage details of the removed energy storage device.

[0012] (7) In the embodiment of (1) above, the charging control unit further comprises a learning unit that learns information relating to the time taken out of the energy storage device and the amount used, and the charging control unit performs charging of the remaining energy storage device based on the information learned by the learning unit.

[0013] (8) In the embodiment of (1) above, the power supply system includes a power generation device, and the charge control unit charges the remaining energy storage device when surplus power is generated by the power generation device.

[0014] (9) In the embodiment of (1) above, the charging control unit performs charging of the energy storage device during a predetermined time period related to electricity charges.

[0015] (10): In the embodiment of (1) above, the charging control unit stops charging the energy storage device when the energy storage device that was taken out of the power supply system is returned to the power supply system and the total remaining power of the energy storage devices installed in the power supply system is equal to or greater than the predetermined remaining amount.

[0016] (11): In the embodiment of (1) above, the charging control unit further comprises a management unit for managing reservations for withdrawals related to the energy storage devices, and when there are energy storage devices for which the management unit has reserved withdrawals from the power supply system, the charging control unit charges the remaining energy storage devices so that the total remaining power of the remaining energy storage devices is equal to or greater than the predetermined remaining amount when the reserved energy storage device is withdrawn.

[0017] (12): Another aspect of the present invention is a charging control method in which a computer of a power supply system equipped with a plurality of detachable energy storage devices charges the energy storage devices from an external power source, detects the total remaining power of the remaining energy storage devices attached to the power supply system after at least one of the plurality of energy storage devices has been removed from the power supply system, and, if the remaining power is less than a predetermined amount, causes the charging unit to charge the remaining energy storage devices. [Effects of the Invention]

[0018] According to the embodiments described in (1) to (12) above, more appropriate charging control can be performed according to the status of the energy storage device in the power supply system. [Brief explanation of the drawing]

[0019] [Figure 1] This figure shows an example of a schematic configuration of the battery charging system 1, including the power supply system. [Figure 2] This figure shows an example of the configuration of the power supply system 100 of the embodiment. [Figure 3] This is a diagram illustrating a first embodiment of charge control. [Figure 4] This flowchart shows an example of the charging control process in the first embodiment. [Figure 5] This is a diagram for explaining a second embodiment of charging control. [Figure 6] This is a flowchart showing an example of the charging control process in the second embodiment. [Figure 7] This is a diagram for explaining a third embodiment of charging control. [Figure 8] This is a diagram showing an example of the process in the learning unit 180. [Figure 9] This is a flowchart showing an example of the charging control process in the third embodiment. [Figure 10] This is a diagram for explaining a modification of the charging control using the prediction model in the third embodiment. [Figure 11] This is a diagram for explaining a fourth embodiment of charging control. [Figure 12] This is a flowchart showing an example of the charging control process in the fourth embodiment. [Figure 13] This is a diagram for explaining a fifth embodiment of charging control. [Figure 14] This is a flowchart showing an example of the charging control process in the fifth embodiment. [Figure 15] This is a diagram for explaining a sixth embodiment of charging control. [Figure 16] This is a flowchart showing an example of the charging control process in the sixth embodiment.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the power supply system and the charging control method of the present invention will be described with reference to the drawings.

[0021] [System Configuration] Figure 1 shows an example of a schematic configuration of a battery charging system 1 including a power supply system. The battery charging system 1 includes a power supply system 100 that can accommodate (install) multiple detachable batteries (an example of an energy storage device) 10, which are used as a household power supply to provide power to household appliances in a home (household). The detachable batteries 10 have a structure that allows them to be attached to and removed from the power supply system 100, and are also rechargeable and dischargeable secondary batteries. The detachable batteries 10 are, for example, lithium-ion batteries (LIBs), nickel-metal hydride batteries, all-solid-state batteries, etc., but are not limited to these. The detachable batteries 10 can also be attached to an electric vehicle 20 in a detachable manner, and by being mounted on the electric vehicle 20, they can supply power to the electric vehicle 20. The detachable batteries 10 may also be power supply devices used for other purposes (for example, a mobile portable power supply). The power supply system 100 is a household (stationary) power supply device. The power supply system 100 may also be discharged from the removable battery 10 in order to perform grid connection or the like. The power supply system 100 may be set up outside the house (HM) or installed inside the house (HM).

[0022] The electric vehicle 20 is a vehicle equipped with a removable battery 10. In the example shown in Figure 1, a saddle-type electric vehicle (electric two-wheeled vehicle) 20-1 and an indoor-type electric vehicle (electric four-wheeled vehicle) 20-2 are shown, both of which are driven by an electric motor powered by electricity supplied by the removable battery 10. For example, the electric vehicle 20-1 shown in Figure 1 can be equipped with two removable batteries 10, and the electric vehicle 20-2 can be equipped with three removable batteries 10. Thus, the number of removable batteries 10 that can be installed varies depending on the type and shape of the electric vehicle 20. Furthermore, the removable batteries 10 that can be used may differ depending on the vehicle model.

[0023] The power supply system 100 charges the removable battery 10 housed in at least one of the multiple slot sections (housing sections) SL provided in the power supply system 100 by receiving power (grid power) from the power supply unit (external power source such as commercial power). The number and shape of the slot sections SL are not limited to the example in Figure 1. Furthermore, the power supply system 100 controls the remaining power to leave a certain amount of power remaining in advance, for purposes such as ensuring that power can be used during power outages caused by disasters, and saving on electricity costs by charging and discharging during predetermined time periods.

[0024] [Example of a power system configuration] Figure 2 shows an example of the configuration of the power supply system 100 in the embodiment. Note that in the example in Figure 2, the slot section SL is omitted. The power supply system 100 includes, for example, an input section 110, an output section 120, a power supply section 130, a detection section 140, a management section 150, a charging section 160, a charging control section 170, a learning section 180, and a storage section 190. At least a part of the detection section 140, the management section 150, the charging section 160, the charging control section 170, and the learning section 180 is realized, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Furthermore, some or all of these components may be implemented by hardware (including circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit), and SOC (System On Chip), or by the collaboration of software and hardware. The program may be stored in advance in a storage device (a storage device equipped with a non-transient storage medium) such as the HDD (Hard Disk Drive) or flash memory of the power supply system 100, or it may be stored in a removable storage medium such as a DVD or CD-ROM, and installed in the HDD or flash memory of the power supply system 100 when the storage medium (non-transient storage medium) is mounted on a drive device.

[0025] The memory unit 190 may be implemented using the various storage devices mentioned above, or an SSD (Solid State Drive), EEPROM (Electrically Erasable Programmable Read Only Memory), ROM (Read Only Memory), or RAM (Random Access Memory), etc. The memory unit 190 stores, for example, a prediction model 192, reservation information 194, a program, and various other information.

[0026] The predictive model 192 is a trained model in which the learning unit 180 has learned the amount of usage of the detachable battery 10 in the electric vehicle 20 according to the elapsed time from when the detachable battery 10 is taken out until it is returned. The elapsed time can also be rephrased as, for example, the elapsed time from when the detachable battery 10 is removed from the power system 100 until it is put back into the power system 100. In the following description, "taking out" the detachable battery 10 is an example of "removing" the detachable battery 10. A specific example of the predictive model 192 will be described later. The reservation information 194 is reservation information that the user has reserved in advance to take out the detachable battery 10 from the power system 100. The reservation information 194 includes information such as the type and number of detachable batteries 10 to be taken out, the start time of taking out, and the scheduled return time.

[0027] The input unit 110 receives various instructions from the user. The input unit 110 may be, for example, a touch panel capable of inputting and outputting information, or it may be buttons, keys, a microphone, etc. The input unit 110 may also communicate with other terminal devices (not shown) by wire or wireless connection and receive input from those terminal devices.

[0028] The output unit 120 outputs various information (e.g., images and audio) to the user. The output unit 120 may be a display unit or a speaker. The display unit may be, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display device. The display unit may also be integrated with the input unit 110 as a touch panel.

[0029] The power supply unit 130 includes, for example, an AC power source such as a commercial power source, and an AC-DC converter that converts the AC power supplied from the AC power source into DC power. The power acquired by the power supply unit 130 is supplied by the charging unit 160 to the removable battery 10 housed in the slot (housing) SL. The power supply unit 130 also supplies power to the house HM. Furthermore, if there is equipment (power generation device) such as PV (photovoltaics; solar power generation) in the house HM, the power supply unit 130 may also supply power generated by the PV to the removable battery 10 or the house HM. The power generation device may be included in the power supply system 100.

[0030] The detection unit 140 detects the remaining power (e.g., SOC (State of Charge) [%]) of the removable batteries 10 housed in the slot section SL. SOC is the power capacity ratio [%] when a fully charged state is 100 [%] and a completely discharged state is 0 [%], and is calculated using a formula such as "SOC = (current power capacity / maximum power capacity) × 100". The detection unit 140 may also detect the remaining power for each removable battery 10, or it may detect the total remaining power (power remaining) of multiple removable batteries 10 housed in multiple slot sections SL. The total remaining power of multiple removable batteries 10 can be calculated, for example, using "SOC = (total power capacity of removable batteries 10 currently housed in slot section SL / total power capacity of removable batteries 10 when removable batteries 10 are housed in all slot sections SL of the power system 100) × 100".

[0031] Furthermore, the detection unit 140 repeatedly detects the remaining power at predetermined intervals. The detection unit 140 may also detect when the removable battery 10 is removed from the slot SL or when the removable battery 10 is returned (stored) in the slot SL, and may detect the remaining power of the removable battery 10 at the time of removal or return.

[0032] The management unit 150 manages the removal and return of the detachable battery 10. Furthermore, when information regarding a reservation for removal of the detachable battery 10 is entered in advance via the input unit 110, the management unit 150 registers and manages this information in the reservation information 194. The management unit 150 also manages the charging mode of the detachable battery 10. The charging modes include, for example, a first mode (normal mode) that does not impose any particular restrictions on the remaining power, and a safety mode (second mode) that basically manages the remaining power to be above a certain level (specified remaining power). However, the types of modes are not limited to these, and other modes may exist.

[0033] The charging unit 160 charges the removable battery 10 housed in the slot unit SL using power supplied by the power supply unit 130, based on control information from the charging control unit 170.

[0034] The charging control unit 170 controls the charging of the removable battery 10 housed in the slot section SL based on the mode and other settings managed by the management unit 150. Details of the functions of the charging control unit 170 will be described later.

[0035] The learning unit 180 learns the relationship between elapsed time and usage based on past usage information (usage history), which includes the elapsed time from when the detachable battery 10 was taken out until it was returned, and the usage amount based on the difference in remaining power before and after taking it out. Based on the learning results, it generates a usage prediction model 192 that corresponds to the amount of usage over time. The generated prediction model 192 is stored in the storage unit 190.

[0036] [Specific examples of charging control] Next, we will describe specific examples of charge control in the embodiment, divided into several examples. In the following, we will describe charge control in a situation where both commercial power (grid power) and PV charging are possible. In the following description, for example, the time period when there is sunlight and surplus power is generated by PV (i.e., the time period when the power generated by PV exceeds the power consumption of the load in the house HM) will be referred to as the "PV generation time period".

[0037] <First Example> Figure 3 is a diagram illustrating a first embodiment of charge control. In the example in Figure 3, the horizontal axis represents time, and the vertical axis represents battery level (remaining power) [%]. Each time point T0 to T14 on the time axis indicates that time has progressed sequentially from time T0 to T14. The battery level is, for example, the remaining power (total remaining power) of one or more removable batteries 10 housed in the slot section SL. This battery level is detected by the detection unit 140. At time T0, it is assumed that removable batteries 10 are housed in all of the slot sections SL provided in the power supply system 100.

[0038] In the first embodiment, the period from time T0 to T5 is assumed to be set to normal mode (first mode) by the user or the like. In this case, the charge control unit 170 starts charging by PV at the start time T1 of the PV power generation period and ends charging at time T2 when it reaches a fully charged state (100[%]). Also, from time T3, power is consumed by the home HM and even if the removable battery 10 reaches a completely discharged state (0[%]) at time T4, it is not the PV power generation period, so the charge control unit 170 remains on standby without charging the removable battery 10.

[0039] Here, let's assume that at time T5, the user has set the safety mode (second mode) via the input unit 110. In this case, the charge control unit 170 will cause the charge unit 160 to perform charging (recovery charging) using grid power (commercial power) in order to bring the battery level to a specified level (X) (an example of a predetermined level). The specified level (X) may be a fixed value, set by the user, or set based on past usage history of the home HM (statistical information on power consumption, etc.). In the example in Figure 3, let's assume that the specified level (X) was set by the user via the input unit 110 at time T5.

[0040] The charging control unit 170 charges the removable battery 10 housed in the slot unit SL, and when charging is completed to the specified remaining capacity (X) at time T6, it stops charging and goes into standby mode. Then, when the PV power generation period begins at time T7, the charging control unit 170 instructs the charging unit 160 to charge the removable battery 10 using power from the PV. When the battery is fully charged at time T8, the charging control unit 170 stops charging and goes into standby mode. Power is consumed by the house HM from time T9, but unless the remaining capacity is below the specified remaining capacity (X), the removable battery 10 remains in standby mode without charging from time T10 onwards.

[0041] Next, at time T11, the user takes out at least one of the multiple removable batteries 10 housed in the power system 100 for use in the electric vehicle 20 or for other reasons, and the remaining battery charge of the remaining removable batteries 10 falls below the specified charge level (X). In this case, since it is not the PV power generation time, the charge control unit 170 instructs the charging unit 160 to perform recovery charging using grid power from the power supply unit 130. Also, at time T12, if the remaining battery charge of the remaining removable batteries 10 becomes equal to or greater than the specified charge level (X), the charge control unit 170 terminates charging and goes into standby mode. Furthermore, when it becomes the PV power generation time at time T13, the charge control unit 170 instructs the charging unit 160 to perform PV charging, and terminates charging at time T14 when each of the remaining removable batteries 10 is fully charged.

[0042] Next, the charging control process in the first embodiment will be explained using a flowchart. Figure 4 is a flowchart of an example of the charging control process in the first embodiment. Note that in the example in Figure 4, the process mainly at times T11 to T13 will be explained. In Figure 4, the detection unit 140 detects that at least one of the multiple removable batteries 10 housed inside has been removed (step S100). Next, the detection unit 140 detects the remaining power of the remaining removable batteries 10 housed inside (step S110). Next, the charging control unit 170 determines whether the remaining power is less than the specified remaining power (step S120). If it is determined that the remaining power is less than the specified remaining power, the charging control unit 170 performs charging control until the remaining power is equal to or greater than the specified remaining power (step S130). This completes this flowchart. Also, if it is determined in step S120 that the remaining power is not less than the specified remaining power, this flowchart also completes.

[0043] According to the first embodiment described above, appropriate charging control can be achieved even if, for example, at least one of the multiple batteries is removed in safety mode. For example, according to the first embodiment, if the removable battery 10 is removed and its remaining charge falls below the specified remaining charge (X), recovery charging can be performed to restore the remaining charge and prepare for unexpected power outages, etc.

[0044] <Second Example> Figure 5 is a diagram illustrating a second embodiment of the charge control. The example in Figure 5 differs from the example in Figure 3 in the processing from time T11 to T13. Therefore, the following explanation will mainly focus on the processing from time T11 to T13, and the explanation of processing at other times will be omitted. In the second embodiment, after the removable battery 10 is removed at time T11, if the remaining battery charge is less than the specified remaining charge (X), the charge control unit 170 suspends (stands) recovery charging until a predetermined time has elapsed, and at time Ta, when the predetermined time has elapsed, it causes the charging unit 160 to start charging from the power supply unit 130. Furthermore, at time T12, when the remaining charge is equal to or greater than the specified remaining charge (X), the charge control unit 170 terminates charging and enters a standby state.

[0045] Figure 6 is a flowchart showing an example of the charging control process in the second embodiment. Note that, as in the example in Figure 6, the process mainly shows the process from time T11 to T13. Furthermore, the process in Figure 6 differs from the process in steps S100 to S130 shown in Figure 4 above in that it includes step S122 between steps S120 and S130. Therefore, the following explanation will focus on the process of step S122.

[0046] In step S120 of Figure 6, if it is determined that the remaining charge is less than the specified remaining charge, the charge control unit 170 determines whether a predetermined time has elapsed since the removable battery 10 was removed (step S122). If it is determined that the predetermined time has not elapsed, the process is suspended (waited) until the predetermined time has elapsed. If it is determined that the predetermined time has elapsed, the charge control unit 170 instructs the charging unit 160 to start charging the removable battery 10 (step S130).

[0047] Here, the predetermined time is set using, for example, at least one of the following conditions. (Condition 1) The discharge time at 1C (the magnitude of the current required to fully charge or fully discharge the battery's theoretical capacity in one hour) is set to a predetermined time. This is a standard value for the output used by the removable battery 10, and there is a high probability that the removable battery 10 will be returned with its charge level completely empty (0%). (Second condition) The predetermined time is the estimated time it takes for the removable battery 10 to become completely empty when discharged at its maximum output (not instantaneous maximum output). For example, if the removable battery 10 has a power capacity of 1 [kWh] and a maximum output of 0.5 "kW", the predetermined time is set to 2 hours. After this time has elapsed, there is a high probability that the removable battery 10 will be returned empty. (Third condition) The time it is estimated that the removable battery 10 will be depleted when discharged at the rated output is defined as a predetermined time. (Fourth condition) The time it is estimated that the removable battery 10 will be depleted when discharged at half (1 / 2) of its maximum output (not the instantaneous maximum output) is defined as a predetermined time. After this time has elapsed, there is a high probability that the removable battery 10 will be returned empty. (Condition 5) The time it is estimated that the removable battery 10 will be depleted when discharged at half (1 / 2) of its rated output is defined as a predetermined time. After this time has elapsed, there is a high probability that the removable battery 10 will be returned empty. (Condition 6) The predetermined time is any time set by the user. (Condition 7) The system acquires information on how the user uses the detachable battery 10 and sets a predetermined time based on the acquired information. For example, if a user uses the detachable battery 10 in an electric vehicle 20-1, and goes to a nearby store, it is preferable not to perform a recharge because the battery will be returned with little charge remaining if the user returns home in about 30 minutes. On the other hand, if the user goes to a distant store, they will not return home for more than 3 hours, and the battery will be returned with almost no charge remaining, so it is preferable to perform a recharge. Therefore, considering these cases, the system has the user input information on how they use the detachable battery 10 (which may include destinations, etc.), and sets a predetermined time based on the input information, allowing charging to be performed at an appropriate time. Furthermore, the method (conditions) for determining the prescribed time is not limited to the examples given above.

[0048] According to the second embodiment described above, by starting charging after a predetermined time has elapsed since the detachable battery 10 was taken out, it is possible to prevent the battery from becoming excessively charged when the detachable battery 10 is returned in a short period of time. Furthermore, according to the second embodiment, it is possible to prevent unnecessary charging.

[0049] <Third Example> Figure 7 is a diagram illustrating a third embodiment of the charge control. The example in Figure 7 differs from the example in Figure 3 in the processing from time T11 to T13. Therefore, the following explanation will mainly focus on the processing from time T11 to T13. In the third embodiment, the charge control unit 170 performs charge control that reflects the data learned by the learning unit 180 (learning data) if the remaining battery charge is less than the specified remaining charge (X) after the removable battery 10 is removed at time T11. For example, in the third embodiment, recovery charging is performed based on the learning data for the amount of usage predicted according to the elapsed time since the removable battery 10 was removed.

[0050] Figure 8 shows an example of processing in the learning unit 180. The horizontal axis in Figure 8 shows the elapsed time [minutes] from the removal to the return of the detachable battery 10, and the vertical axis shows the amount of energy [Wh] used from the removed detachable battery 10. Based on the past usage history of the detachable battery 10, the learning unit 180 adds the relationship between the elapsed time from the removal to the return of the detachable battery 10 and the amount of energy used based on the difference in remaining power before and after removal to the learning data. The learning unit 180 then plots the learning data on the coordinate plane shown in Figure 8 and uses known regression analysis processing, etc., with each plotted point to generate a predictive model 192 that shows the relationship between elapsed time and amount of energy used. The predictive model 192 may be a curve or a straight line. The learning process in the learning unit 180 may be performed in advance, or it may be executed repeatedly at a predetermined period or timing. By repeatedly learning, the accuracy of the predictive model 192 can be improved.

[0051] The charging control unit 170 predicts the amount of power used by the removable battery 10 based on the prediction model 192 learned by the learning unit 180, and sets the predicted amount of power as the recovery power amount. The charging control unit 170 then controls the charging unit 160 to charge the remaining removable battery 10 with the power of the set recovery power amount.

[0052] Figure 9 is a flowchart showing an example of the charging control process in the third embodiment. Note that the example in Figure 9 also mainly shows the process from time T11 to T13. The process in Figure 9 differs from the process shown in Figure 4 above in that it includes step S132 instead of step S130, and also includes step S124 between steps S120 and S132. Therefore, the following explanation will mainly focus on the processes of steps S124 and S132.

[0053] In step S120 of Figure 9, if it is determined that the remaining charge is less than the specified remaining charge, the charging control unit 170 predicts the amount of power that will be used by the removable battery 10 over time based on the prediction model 192 learned by the learning unit 180 (step S124). Then, the charging control unit 170 performs charging control to charge the removable battery 10 with the predicted amount of power (step S132).

[0054] According to the third embodiment described above, after the removable battery 10 is taken out, recovery charging is performed for the amount of battery usage predicted from learning data showing the relationship between the time taken out and the amount of battery usage of the removable battery 10. This prevents the battery level from becoming excessive when the removable battery 10 is returned. Furthermore, according to the third embodiment, unnecessary charging can be suppressed, thus enabling more appropriate charging control.

[0055] Figure 10 illustrates a modified example of charge control using a prediction model in the third embodiment. The example in Figure 10 combines the second and third embodiments. Based on the prediction model 192, the charge control unit 170 can predict the amount of power used by the removed detachable battery 10 over time. It then obtains the time when the amount of power exceeds a threshold Th1, waits until that time has elapsed, and then controls the system to start charge control (recovery charge) after that time has passed. This allows the effects of both the second and third embodiments to be obtained, resulting in more appropriate charge control.

[0056] <Fourth Example> Figure 11 is a diagram illustrating a fourth embodiment of the charge control. The example in Figure 11 differs from the second embodiment shown in Figure 5 in that the charge control is performed at time Ta, a predetermined time after the removable battery 10 has been taken out, and the removable battery 10 is returned at time Tb, before time T13. Therefore, the following explanation will mainly focus on the above differences. When the removable battery 10 is returned at time Tb, the charge control unit 170 determines whether the battery charge detected by the detection unit 140 at the time of return is equal to or greater than the specified charge (X). If it is equal to or greater than the specified charge (X), the charge control unit terminates the ongoing charge and waits. In the example in Figure 11, the charge was terminated because the battery charge reached or exceeded the specified charge (X) at time Tb when the removable battery 10 was returned.

[0057] Figure 12 is a flowchart showing an example of the charging control process in the fourth embodiment. Note that the example in Figure 12 also shows the process from time T11 to T13. The process in Figure 12 differs from the steps S100 to S130 shown in Figure 4 above in that steps S140 to S180 are added after step S130. Therefore, the following explanation will mainly focus on the processes from steps S140 to S180.

[0058] During the charging control process in step S130 of Figure 12, when the detection unit 140 detects the return of the removable battery 10 (step S140), it detects the remaining charge of the housed removable battery 10 (step S150). Next, the charging control unit 170 determines whether the detected remaining charge is above a specified threshold (step S160). If it determines that it is above the specified threshold, the charging control unit 170 terminates the ongoing charging (step S170). If it determines that it is not above the specified threshold, it continues the ongoing charging (step S180).

[0059] According to the fourth embodiment described above, when the removed detachable battery 10 is returned and the remaining charge of the returned battery exceeds the specified remaining charge, recovery charging is stopped. This allows charging to be stopped promptly as soon as the remaining charge is secured, thus preventing overcharging. Therefore, more appropriate charging control can be performed depending on the situation.

[0060] <Fifth Example> Figure 13 is a diagram illustrating a fifth embodiment of the charge control. In the fifth embodiment, after the removable battery 10 is removed at time T11, the system waits until the PV power generation period (i.e., the period when surplus power is generated by PV) before performing recovery charge control. Specifically, as shown in Figure 13, when the removable battery 10 is removed and it is determined that the battery level falls below the specified remaining level (X), the charge control unit 170 waits until the PV power generation period begins and starts charging at time Tc, which is the start of the PV power generation period. In this charging, the charge control unit 170 does not continue charging until the remaining battery level is equal to or greater than the specified remaining level (X), but rather until each of the remaining removable batteries 10 housed in the slot section SL of the power supply system 100 is fully charged, and the charging ends at time T14 when the batteries are fully charged.

[0061] In the fifth embodiment, the PV power generation time period may be replaced with the nighttime electricity period. The nighttime electricity period is the time period when the cost of using commercial power (electricity charges) is cheaper than during the daytime.

[0062] Figure 14 is a flowchart showing an example of the charge control process in the fifth embodiment. The process in Figure 14 differs from steps S100 to S130 shown in Figure 4 in that it includes step S126 between steps S120 and S130. Therefore, the following explanation will mainly focus on the process in step S126.

[0063] In step S120 of Figure 14, if it is determined that the remaining charge is less than the specified remaining charge, the charge control unit 170 determines whether the current time period is the PV power generation time period or the nighttime electricity time period (step S126). If it is determined that it is the PV power generation time period or the nighttime electricity time period, the charge control unit 170 executes charge control (step S130). If it is determined that it is neither the PV power generation time period nor the nighttime electricity time period, it waits without executing charge control.

[0064] According to the fifth embodiment described above, the electricity cost for regenerative charging can be reduced compared to charging using power from commercial power sources during the day. Therefore, more appropriate charging control can be achieved.

[0065] <Sixth Example> Figure 15 is a diagram illustrating a sixth embodiment of the charge control. In the sixth embodiment, when the removal of the removable battery 10 is reserved, the remaining charge of the reserved battery is not included in the total remaining charge value when performing charge control. In the process shown in Figure 15, the process from time T0 to T6 is the same as in the other embodiments, but the process thereafter (processing from time T20 to T26) differs from the other embodiments, so the explanation will mainly focus on the process from time T20 to T26.

[0066] If information regarding the reservation to remove the removable battery 10 is received from the input unit 110 at time T20, the management unit 150 registers the received information in the reservation information 194. Based on the reservation information 194, the charge control unit 170 performs additional charging so that the remaining charge of the remaining removable batteries 10, excluding the removable battery 10 scheduled to be removed as reserved in advance, is equal to or greater than the specified remaining charge (X). In this case, the charge control unit 170 performs additional charging control so that the battery charge detected by the detection unit 140 is equal to or greater than the sum of the remaining charge of the removable battery 10 reserved for removal (reserved removal amount) and the specified remaining charge (X) (hereinafter referred to as the added remaining charge).

[0067] Furthermore, at time T21, if the total remaining charge exceeds the specified remaining charge (X) + reserved amount for removal, the charging control unit 170 stops charging and goes into standby mode. Then, at time T22, which is the PV power generation time, the charging control unit 170 starts charging using PV and brings each of the housed removable batteries 10 to a fully charged state. At time T23, when the batteries are fully charged, the charging control unit 170 stops charging, and at time T24, the remaining charge decreases due to power consumption by the home HM. Also, at time T25, when consumption by the home HM has ended, the remaining charge is greater than or equal to the total remaining charge, so the unit goes into standby mode without charging. By performing this control, even if a removable battery 10 that was reserved is removed at time T26, the battery remaining charge can be maintained at or above the specified remaining charge (X).

[0068] Figure 16 is a flowchart showing an example of the charging control process in the sixth embodiment. Note that in the following process, it is assumed that reservation information 194 has already been registered. In the process shown in Figure 16, the detection unit 140 detects the remaining power of the removable battery (including information on reserved batteries) housed in the slot SL of the power supply system 100 (step S200). Next, the charging control unit 170 obtains the reservation information for the removal of the removable battery 10 (reservation information 194) from the storage unit 190, etc. (step S200).

[0069] Next, the charging control unit 170 determines whether the remaining power is less than the specified remaining power plus the reserved amount to be taken out (additional remaining power) (step S220). If the remaining power is less than the specified remaining power plus the reserved amount to be taken out, the charging control unit 170 executes charging control (step S230). This completes this flowchart. Also, if the process in step S220 determines that the remaining power is not less than the specified remaining power plus the reserved amount to be taken out, this flowchart also completes.

[0070] According to the sixth embodiment described above, when the removal of the removable battery 10 is reserved, the power of the reserved removable battery 10 is not included in the comparison with the specified remaining charge, thereby ensuring that the specified remaining charge is secured even when the reserved removable battery 10 is removed.

[0071] [Differentiation] Each of the first to sixth embodiments described above may be combined with at least one other embodiment. For example, as shown in the sixth embodiment, if a battery removal reservation is registered and the remaining charge is less than the specified remaining charge + the reserved removal amount (additional remaining charge), the battery may be charged after waiting until the PV power generation time (or nighttime electricity time), as shown in the fifth embodiment. Furthermore, if charging becomes necessary after the reserved removable battery has been removed, recovery charging may be performed after waiting for a predetermined time, as shown in the second embodiment. This ensures that even when a battery removal reservation is made, charging will occur during the PV power generation time (or nighttime electricity time) or after waiting for a certain period of time, thereby preventing recovery charging at high electricity rates or excessive recovery charging. Therefore, more appropriate charging control can be achieved.

[0072] Furthermore, in the embodiments, the choice of which of the first to sixth embodiments described above to use, and how to combine them, may be selected by the user, for example, and may be set according to the condition of the detachable battery 10 (e.g., degree of degradation), power costs, usage conditions (frequency and number of times it is taken out), etc.

[0073] Furthermore, in this embodiment, when the charge control unit 170 charges the remaining removable batteries 10, it may charge each removable battery 10 evenly, or it may prioritize charging the battery with the lowest remaining charge. In addition, the charge control unit 170 may prioritize charging the removable battery 10 that is less degraded, or it may prioritize charging the newer removable battery 10. This allows for more appropriate charge control according to the state of the removable batteries 10.

[0074] Furthermore, the power supply system 100 may be for commercial facilities rather than for home use. Also, the power supply system 100 may be a battery exchange station that provides services such as charging and replacement (return, lending) of removable batteries 10 as a power source for electric vehicles 20.

[0075] As described above, the power supply system of the embodiment is a power supply system 100 equipped with a plurality of removable batteries 10 (an example of an energy storage device), and includes a charging unit 160 that charges the removable batteries 10 from an external power source, a detection unit 140 that detects the total remaining power of the remaining removable batteries installed in the power supply system 100 after at least one of the plurality of removable batteries 10 has been removed from the power supply system 100, and a charge control unit 170 that causes the charging unit 160 to charge the remaining removable batteries when the remaining power is less than a predetermined amount, thereby enabling more appropriate charge control according to the status of the energy storage device in the power supply system.

[0076] For example, according to this embodiment, more appropriate charging control can be achieved in the safety mode control of a stationary ESS (Energy Storage System) equipped with a removable battery 10. Furthermore, according to this embodiment, if the removable battery 10 is removed from the power system 100 and its remaining charge falls below a specified level, charging can be performed until the remaining charge recovers to or above the specified level, thereby providing protection against unexpected power outages. Furthermore, according to the embodiment, by starting charging after a predetermined time has elapsed since the removable battery 10 was taken out, or by performing charging based on the learned results of the relationship between the time taken out and the amount used, it is possible to suppress the remaining charge from becoming excessive when the removable battery 10 is returned immediately after being taken out. Therefore, it is possible to suppress unnecessary charging. Furthermore, according to this embodiment, charging can be performed using inexpensive electricity by carrying out the charging during a predetermined time period when electricity rates are low (and not during a time period when rates are high). Furthermore, according to this embodiment, since the detachable battery 10 is returned and charging is promptly stopped once sufficient charge is secured, it is possible to prevent overcharging. Furthermore, according to this embodiment, the remaining charge is secured by excluding the reserved detachable battery 10, so even if the reserved detachable battery 10 is taken out, the specified remaining charge can be secured.

[0077] The embodiments described above can be expressed as follows. A storage medium for storing computer-readable instructions in a power system equipped with multiple removable energy storage devices, A processor connected to the storage medium, The processor executes the computer-readable instructions to: The energy storage device is charged from an external power source, After at least one of the plurality of energy storage devices is removed from the power supply system, the total remaining power of the remaining energy storage devices attached to the power supply system is detected. If the remaining power is less than a predetermined amount, the remaining energy storage device is charged to the charging unit. Power supply system.

[0078] Although embodiments for carrying out the present invention have been described above using examples, the present invention is not limited in any way to these embodiments, and various modifications and substitutions can be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0079] 10…Removable battery (energy storage device), 20…Electric vehicle, 100…Power supply system, 110…Input unit, 120…Output unit, 130…Power supply unit, 140…Detection unit, 150…Management unit, 160…Charging unit, 170…Charging control unit, 180…Learning unit, 190…Memory unit

Claims

1. A power supply system comprising multiple detachable energy storage devices, A charging unit that charges the energy storage device from an external power source, A detection unit detects the total remaining power of the remaining power storage devices attached to the power system after at least one of the plurality of power storage devices has been removed from the power system. A charge control unit that causes the remaining power to charge the charging unit when the remaining power is less than a predetermined amount, A power supply system equipped with the following features.

2. The charging control unit, when at least one of the plurality of energy storage devices is disconnected from the power supply system, causes the charging unit to charge the remaining energy storage devices attached to the power supply system so that the total remaining power of the remaining devices is equal to or greater than the predetermined remaining amount. The power supply system according to claim 1.

3. The charging control unit shall charge the remaining energy storage devices after a predetermined time has elapsed since at least one of the plurality of energy storage devices was disconnected from the power supply system. The power supply system according to claim 1.

4. The predetermined time is set based on the elapsed time from when the energy storage device is removed until it is returned. The power supply system according to claim 3.

5. The predetermined time is set based on the maximum output or rated output of the energy storage device. The power supply system according to claim 3.

6. The predetermined time is set based on the usage details of the removed energy storage device. The power supply system according to claim 3.

7. The system further includes a learning unit that learns information regarding the relationship between the time it takes out of the energy storage device and the amount of energy used. The charging control unit performs charging of the remaining energy storage device based on the information learned by the learning unit. The power supply system according to claim 1.

8. The aforementioned power supply system includes a power generation device, The charging control unit, when surplus power is generated by the power generation device, performs charging of the remaining energy storage device. The power supply system according to claim 1.

9. The charging control unit performs charging of the energy storage device during a predetermined time period related to electricity charges. The power supply system according to claim 1.

10. The charging control unit stops charging the energy storage device when the energy storage device that was taken out of the power supply system is returned to the power supply system, and the total remaining power of the energy storage devices installed in the power supply system is equal to or greater than the predetermined remaining power. The power supply system according to claim 1.

11. The system further includes a management unit for managing reservations for energy extraction related to the aforementioned energy storage device. If there is a power storage device whose power supply is reserved by the management unit for removal from the power supply system, the charging control unit will charge the remaining power storage devices so that the total remaining power of the remaining power storage devices is equal to or greater than the predetermined remaining amount when the reserved power storage device is removed. The power supply system according to claim 1.

12. A computer in a power system equipped with multiple detachable energy storage devices, The energy storage device is charged from an external power source, After at least one of the plurality of energy storage devices is removed from the power supply system, the total remaining power of the remaining energy storage devices attached to the power supply system is detected. If the remaining power is less than a predetermined amount, the remaining energy storage device is charged to the charging unit. Charging control method.

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