Power supply system and energy management method

Abstract

The present application relates to a power supply system and an energy management method. In the power supply system, a control device is configured to select one or more subject batteries that perform a required energy management from among a plurality of batteries included in an AC battery string and a DC battery string, and perform the required energy management using the subject batteries in a state in which the batteries other than the subject batteries are cut off from a circuit.

Description

Technical Field

[0001] This disclosure relates to power systems and energy management methods, and more particularly to power systems and energy management methods using battery strings. Background Technology

[0002] Japanese Patent Application Publication No. 2018-074709 discloses a control circuit for controlling a battery string. The battery string includes multiple battery circuit modules interconnected. Each battery circuit module in the battery string includes a battery, a first switch connected in parallel with the battery, a second switch connected in series with the battery, and a first output terminal and a second output terminal to which the battery voltage is applied when the first switch is in an open state and the second switch is in an on state. By controlling the first and second switches of each battery circuit module in the battery string, the control circuit can adjust the output voltage of the battery string to a desired level. Summary of the Invention

[0003] Japanese Patent Application Publication No. 2018-074709 discloses a power supply system that uses the battery string described above to output DC power. However, Japanese Patent Application Publication No. 2018-074709 does not conduct any research on the power waveform (AC power) output using the battery string. Furthermore, Japanese Patent Application Publication No. 2018-074709 also does not conduct any research on energy management using the battery string.

[0004] This disclosure provides a power system and energy management method capable of using battery strings for appropriate energy management.

[0005] The power supply system of the first embodiment of this disclosure includes a first power supply circuit, a second power supply circuit, and a control device. The first power supply circuit includes a DC battery string for DC power and a converter for converting the DC power output from the DC battery string into AC power, configured to output first AC power using the DC battery string and the converter. The second power supply circuit includes an AC battery string for AC power, configured to output second AC power using the AC battery string. The control device is configured to control the first power supply circuit and the second power supply circuit. Each of the AC battery string and the DC battery string includes multiple battery circuit modules connected in series. Each of the multiple battery circuit modules includes a battery, an output terminal for outputting the battery voltage, a first switch connected to the output terminal and in parallel with the battery, and a second switch connected in series with the battery. Each of the multiple battery circuit modules is configured such that when the first switch is in an off state and the second switch is in an on state, the battery voltage is applied to the output terminal. The control device is configured to select one or more target batteries from the multiple batteries included in the AC battery string and the DC battery string to perform the required energy management, and to use the target battery to perform the required energy management while disconnecting batteries other than the target battery from the circuit.

[0006] The aforementioned power system can select the target battery that meets the energy management requirements from among the multiple batteries in each battery string. Even when batteries other than the target battery are disconnected from the circuit, the target battery performs energy management. This structure allows the batteries that do not perform energy management (batteries other than the target battery in the battery string) to remain in a state where appropriate energy management can be achieved using the target battery.

[0007] Furthermore, the aforementioned power supply system can easily output various types of AC power using the first and second power supply circuits. Specifically, the first power supply circuit can use a converter to generate a power waveform (AC power) based on the DC power output from the DC battery string. The second power supply circuit can adjust the number of batteries connected to the circuit by controlling the first and second switches of each battery circuit module included in the AC battery string. Additionally, different types of batteries (e.g., high-capacity batteries / high-output batteries) can be used in the AC and DC battery strings. Therefore, according to the above structure, it becomes easy to expand the output voltage range (V) and power range (kW) or extend the output time in the design of the power supply system. Thus, the aforementioned power supply system has a structure that easily responds to various energy management requirements.

[0008] The aforementioned control device can be configured to perform degradation diagnosis on each of the one or more batteries in an AC battery string and the one or more batteries in a DC battery string using data successively acquired during at least one of the charging and discharging processes of that battery. Furthermore, the control device can be configured to determine whether a required power change in energy management is suitable for degradation diagnosis. The control device can also be configured to, if it is determined that the required power change in energy management is not suitable for degradation diagnosis, exclude one or more batteries from the pool of batteries in the AC and DC battery strings that are undergoing degradation diagnosis from the selected candidate batteries.

[0009] In the aforementioned power system, the control device uses data acquired sequentially during at least one of the battery's charging and discharging processes (e.g., changes in battery voltage and / or battery current) to perform battery degradation diagnosis. If the battery being diagnosed participates in energy management with power fluctuations too large to obtain suitable data during the degradation diagnosis process, the degradation diagnosis will be redone. Therefore, in the aforementioned power system, if the power fluctuations in energy management are not suitable for degradation diagnosis, the battery undergoing degradation diagnosis is prevented from participating in energy management, thereby suppressing the redoing of degradation diagnosis. The battery undergoing degradation diagnosis is disconnected from the circuit during the degradation diagnosis process, maintaining its state during the execution of energy management. After the energy management process ends, the control device can restart the interrupted degradation diagnosis.

[0010] It should be noted that the control device can perform degradation diagnosis on all the batteries in the battery string, or it can perform degradation diagnosis on a specified number of batteries in the battery string as a representative.

[0011] The control device described above can be configured such that, when the duration of the required energy management is greater than or equal to a first reference value, it is determined that the power variation of the required energy management is suitable for degradation diagnosis.

[0012] In long-term energy management, there is a tendency for power fluctuations to become slow. Based on the above structure, it is easy and straightforward to determine whether the power fluctuations required for the energy management are suitable for degradation diagnosis.

[0013] The control device described above can be configured such that, when the response time of the required energy management is below a second reference value, it is determined that the power fluctuation of the required energy management is not suitable for degradation diagnosis.

[0014] In energy management with short response times, there is a tendency for power fluctuations to increase. Based on the above structure, it is easy and straightforward to determine whether the power fluctuations of the required energy management are suitable for degradation diagnosis.

[0015] The power density of batteries in a DC battery string can be higher than that of batteries in an AC battery string. Furthermore, the energy density of batteries in an AC battery string can be higher than that of batteries in a DC battery string.

[0016] Based on the above structure, various types of AC power can be output using the first power supply circuit and the second power supply circuit. For example, by using a high-capacity battery (a battery with high energy density), long-term power supply can be easily achieved. In addition, by using a high-output battery (a battery with high power density), high-speed power supply can be easily achieved.

[0017] Hereinafter, each battery in a DC battery string will also be referred to as a "DC battery". The power density of a DC battery can be above 1000W / kg, above 1500W / kg but less than 5000W / kg, or above 5000W / kg. The energy density of a DC battery can be less than 300Wh / kg, less than 100Wh / kg, or above 50Wh / kg but less than 500Wh / kg.

[0018] Hereinafter, each battery in an AC battery string will also be referred to as an "AC battery". The energy density of an AC battery can be above 300Wh / kg, above 500Wh / kg but less than 1000Wh / kg, or above 1000Wh / kg. The power density of an AC battery can be less than 1000W / kg, or above 300W / kg but less than 1000W / kg.

[0019] In any of the aforementioned power supply systems, the first power supply circuit and the second power supply circuit can each be electrically connected to an external power source that will supply power to the building and to the electrical wiring connecting the building. The aforementioned energy management can be power regulation of the external power source.

[0020] According to the above structure, AC power can be supplied to the building from both the first and second power circuits. Furthermore, power from an external power source can be used to charge both the AC and DC batteries, thus allowing each of the first and second power circuits to store power as needed. This power system can function as an emergency power source for the building. The external power source can be an electrical system.

[0021] Any of the power supply systems described above may further include an insulation filter disposed between the first power supply circuit and the aforementioned wires. The converter may be a reused product that has been used for other purposes.

[0022] In a system where the converter is a reused component, the desired AC power waveform may not be obtained using the converter. Therefore, in the above structure, an insulation filter is provided between the first power supply circuit and the aforementioned wires. With such an insulation filter, the desired AC power waveform can be easily obtained, and the noise contained in the output (AC power) of the first power supply circuit can be easily reduced.

[0023] For example, a recycled material that has been used as a driving converter in an electric vehicle (hereinafter also referred to as "xEV") (i.e., a converter removed from the xEV after use) can be used as the aforementioned converter. A driving converter is, for example, a converter that drives a driving electric motor in an xEV. An xEV is a vehicle that utilizes electricity as a power source, either entirely or partially. xEVs include BEVs (battery electric vehicles), PHEVs (plug-in hybrid electric vehicles), and FCEVs (fuel cell electric vehicles).

[0024] The first power supply circuit may include a first drive circuit that drives the first and second switches included in the DC battery string, and a first control circuit that sends signals to the first drive circuit for driving the first and second switches respectively according to instructions from a control device. The second power supply circuit may include a second drive circuit that drives the first and second switches included in the AC battery string, and a second control circuit that sends signals to the second drive circuit for driving the first and second switches respectively according to instructions from a control device.

[0025] Based on the above structure, the AC battery string and the DC battery string can be properly controlled by the first control circuit and the second control circuit.

[0026] In the aforementioned power system, the converter can be a three-phase converter. The control device can be configured to send commands for controlling the DC battery strings to a first control circuit and control the converter, in a manner that outputs three-phase AC power from a first power supply circuit. The AC battery strings may include a U-phase battery string, a V-phase battery string, and a W-phase battery string that are Y-connected. The control device can also be configured to send commands for controlling the U-phase battery strings, the V-phase battery strings, and the W-phase battery strings to a second control circuit, in a manner that outputs three-phase AC power from a second power supply circuit.

[0027] Based on the above structure, three-phase AC power can be output from both the first power supply circuit and the second power supply circuit. The voltage of the three-phase AC power can be above 190V and below 300V, or it can be 200V.

[0028] The power system of the second embodiment of this disclosure includes a battery string and a control device for controlling the battery string. The battery string includes multiple battery circuit modules connected in series. Each of the multiple battery circuit modules includes a battery, an output terminal for outputting the battery voltage, a first switch connected to the output terminal and in parallel with the battery, and a second switch connected in series with the battery. Each of the multiple battery circuit modules is configured such that when the first switch is in an off state and the second switch is in an on state, the battery voltage is applied to the output terminal. The control device is configured to select one or more target batteries from the multiple batteries included in the battery string to perform the required energy management, and to use the target battery to perform the required energy management while disconnecting batteries other than the target battery from the circuit. Furthermore, the control device is configured to perform a degradation diagnosis of each of the multiple batteries included in the battery string using data successively acquired during at least one of the charging and discharging processes of that battery. The control device is configured to determine whether the power variation of the required energy management is suitable for degradation diagnosis. The control device is configured such that, if it is determined that the power fluctuation required for energy management is not suitable for degradation diagnosis, one or more batteries in the battery string included in the degradation diagnosis are excluded from the candidate batteries for the target battery.

[0029] The power system of the second embodiment described above, like the power system of the first embodiment described above, can maintain the state of batteries (batteries other than the target battery in the battery string) that do not perform energy management, and can use the target battery for appropriate energy management. Furthermore, according to the power system having the above structure, degradation diagnostic redoing can be suppressed.

[0030] The third energy management method disclosed herein is a method for energy management using a battery string. The battery string includes multiple battery circuit modules connected in series. Each of the multiple battery circuit modules includes a battery, an output terminal for outputting the battery voltage, a first switch connected to the output terminal and in parallel with the battery, and a second switch connected in series with the battery. Each of the multiple battery circuit modules is configured such that when the first switch is in an off state and the second switch is in a conducting state, the battery voltage is applied to the output terminal. This energy management method includes the following steps: determining whether the power fluctuation required for the requested energy management is large; if the power fluctuation is determined to be small, designating multiple batteries in the battery string as candidates for target batteries; if the power fluctuation is determined to be large, removing one or more batteries from the multiple batteries in the battery string for degradation diagnosis, and designating the remaining batteries as candidates for target batteries; selecting one or more target batteries from the candidate target batteries; controlling the first switch and the second switch in a manner that disconnects batteries other than the target batteries from the circuit; and using the target batteries to perform the requested energy management while the batteries other than the target batteries are disconnected from the circuit.

[0031] The energy management method of the third aspect of this disclosure, like the power system of the second aspect of this disclosure, can maintain the state of a battery that does not perform energy management and use the target battery for appropriate energy management. By maintaining the state of the battery during degradation diagnosis, the need for degradation diagnosis redoing can be suppressed.

[0032] According to the above-described solution of this disclosure, a power system and energy management method capable of using battery strings for appropriate energy management can be provided. Attached Figure Description

[0033] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, wherein:

[0034] Figure 1 This is a diagram illustrating the structure of a power supply system according to an embodiment of the present disclosure.

[0035] Figure 2 It is shown Figure 1 The diagram shows the structure of each scanning unit in the power supply system.

[0036] Figure 3 Is Figure 2 The scan unit shown is a timeline illustrating an example of the operation of a battery circuit module controlled by a gate signal.

[0037] Figure 4 Is Figure 2The diagram shown illustrates the battery circuit module in its operational state within the scanning unit.

[0038] Figure 5 Is Figure 2 The scan unit shown illustrates the state of the battery circuit module during the delay period.

[0039] Figure 6 Is Figure 2 The scan unit shown illustrates the state of the battery circuit module during the stop period.

[0040] Figure 7 It is used for in Figure 2 The diagram illustrates an example of scan control performed in the scan unit shown.

[0041] Figure 8 It is shown Figure 1 A diagram showing the detailed structure of the converter.

[0042] Figure 9 This is a diagram showing the structure of the second power supply circuit.

[0043] Figure 10 It is shown Figure 1 The flowchart shown is a first example of the process involved in battery degradation diagnosis performed by the GCU (control unit).

[0044] Figure 11 It is shown Figure 1 The flowchart shown is a second example of the process involved in the battery degradation diagnosis performed by the GCU (control unit).

[0045] Figure 12 This is a diagram illustrating one example of the types and contents of energy management.

[0046] Figure 13 It is shown Figure 1 The flowchart shown is an example of the energy management processes performed by the GCU (Control Unit).

[0047] Figure 14 It is shown Figure 13 The flowchart shown details the processing involved in selecting the target battery.

[0048] Figure 15 It shows based on Figure 13 The flowchart shown details the processes involved in remotely controlled power adjustments.

[0049] Figure 16 It shows based on Figure 13 The flowchart shown details the processing involved in the local control power adjustment.

[0050] Figure 17It is shown Figure 13 The diagram shows an example of the state of each battery when the power adjustment is performed by the scan control. Detailed Implementation

[0051] Hereinafter, embodiments of this disclosure will be described with reference to the accompanying drawings. Figure 1 The following is a detailed explanation. It should be noted that the same or similar parts in the diagram will be labeled with the same reference numerals without repeated explanations. Hereinafter, the String Control Unit (SCU) will be referred to as "SCU," and the Group Control Unit (GCU) as "GCU." Additionally, alternating current (AC) is sometimes referred to as "AC," and direct current (DC) as "DC."

[0052] Figure 1 This is a diagram illustrating the structure of the power supply system according to this embodiment. The power supply system 1 includes a first power supply circuit 2, a second power supply circuit 3, insulation filters T1 and T2, relays R1 and R2, a distribution board C1, and a GCU 100. The GCU 100 corresponds to an example of the "control device" of this disclosure. The GCU 100 can be a computer. The GCU 100 includes, for example, a processor, RAM (Random Access Memory), and a storage device (none shown). Various processes are performed by executing programs stored in the storage device through the processor. However, the various processes in the GCU 100 are not limited to software-based execution; they can also be performed using dedicated hardware (electronic circuits). In this embodiment, the power supply system 1 is applied to a building 300 such as a residence, school, hospital, commercial facility, or station.

[0053] The power system PG supplies electricity to building 300 via power lines PGL. The power system PG is a power grid constructed from transmission and distribution equipment. Multiple power plants are connected to the power system PG. The power system PG receives power from these power plants. In this embodiment, the power company maintains and manages the power system PG (commercial power source). The power company is equivalent to the TSO (System Operator). The power system PG supplies three-phase AC power to building 300. The power system PG is equivalent to an example of the "external power source" of this disclosure. The supply and demand status of the power system PG is managed by server 200. Server 200 is configured to communicate with GCU 100. In this embodiment, server 200 belongs to the power company. However, it is not limited to this; server 200 may also be a server belonging to an integrator, or a server that trades in the electricity market (e.g., a supply and demand adjustment market).

[0054] The first power supply circuit 2 and the second power supply circuit 3 are each configured to receive and transmit power to the power system PG. The first power supply circuit 2 and the second power supply circuit 3 sometimes receive power from the power system PG and sometimes supply power to the power system PG. The first power supply circuit 2 and the second power supply circuit 3 are each electrically connected to the wire PGL (the wire connecting the power system PG and the building 300) via the distribution board C1. However, a relay R1 and an insulation filter T1 are installed between the wire PGL and the first power supply circuit 2 (more specifically, between the distribution board C1 and the first power supply circuit 2). Additionally, a relay R2 and an insulation filter T2 are installed between the wire PGL and the second power supply circuit 3 (more specifically, between the distribution board C1 and the second power supply circuit 3).

[0055] The distribution board C1 is equipped with a residual current device (RCD) and / or a circuit breaker. Additionally, power sensors C1a and C1b are installed on the distribution board C1. Power sensor C1a includes a current sensor that detects the current (input / output current) flowing between the first power circuit 2 and the wire PGL, and a voltage sensor that detects the input / output voltage of the first power circuit 2. Power sensor C1b includes a current sensor that detects the current (input / output current) flowing between the second power circuit 3 and the wire PGL, and a voltage sensor that detects the input / output voltage of the second power circuit 3. The detection results of power sensors C1a and C1b are output to the GCU100. The distribution board C1 may also include an electric force meter (not shown).

[0056] The distribution board C2, installed within building 300, is configured to receive power from both the power system PG and the power supply system 1. The distribution board C2 is connected to the building wiring and distributes power supplied from at least one of the power system PG and the power supply system 1 to the building wiring.

[0057] A power sensor C1c is installed on the distribution board C2. The power sensor C1c includes a current sensor for detecting the current flowing in the wire PGL and a voltage sensor for detecting the voltage applied to the wire PGL. The power (current and voltage) detected by the power sensor C1c is equivalent to the power (current and voltage) supplied from the power system PG to the building 300. The detection result of the power sensor C1c is output to the GCU100. The distribution board C2 may also also include an electric power meter (not shown).

[0058] The first power supply circuit 2 includes battery strings St1, St2, and St3, converters 11, 21, and 31, and SCUs 12, 22, and 32. The second power supply circuit 3 includes battery strings St4 to St9 and SCUs 41 to 46. The battery strings in the first power supply circuit 2 and the second power supply circuit 3 constitute a scanning unit SU.

[0059] Figure 2This is a diagram showing the structure of the scanning unit SU. (and...) Figure 1 Refer to together Figure 2 In the power system 1 of this embodiment, the battery string St (equivalent to Figure 1 The battery strings St1 to St9 shown, and the multiple drive circuits SUA that drive the switches (SW51 and SW52 described later) within the battery string St. Figure 1 (not shown in the diagram) and the SCU (equivalent to) that sends control signals to the drive circuit SUA. Figure 1 The SCUs 12, 22, 32, and 41-46 shown are modular scanning units SU mounted on the first power supply circuit 2 and the second power supply circuit 3, respectively. It should be noted that multiple drive circuits SUA can also be integrated onto a single substrate. Alternatively, the scanning unit SU can also be a single circuit board.

[0060] The battery string St has multiple battery circuit modules M connected in series. In this embodiment, the battery string St contains approximately 20 battery circuit modules M, but this number is arbitrary and can be 5 to 50, or even more than 100. In this embodiment, each battery string in the first power circuit 2 and the second power circuit 3 includes the same number of battery circuit modules M, but the number of battery circuit modules M may differ for each battery string.

[0061] Each battery circuit module M includes a power circuit SUB and a housing Cg. The housing Cg includes a battery B and a monitoring unit BS. The power circuit SUB and the battery B are connected to form a battery circuit module M including the battery B. A drive circuit SUA is provided for each battery circuit module M. Furthermore, the drive circuit SUA is configured to drive the switches (more specifically, SW51 and SW52, described later) included in the battery circuit module M. Details regarding the battery B will be described later. In this embodiment, different types of batteries are used in the first power circuit 2 and the second power circuit 3.

[0062] like Figure 2 As shown, each battery circuit module M also includes cut-off devices RB1 and RB2 (hereinafter referred to as "cut-off devices RB" without distinction). The power circuit SUB and the cartridge Cg are interconnected via cut-off devices RB1 and RB2. The SCU is configured to switch the connection state (on / off) between the power circuit SUB and the cartridge Cg by controlling the on / off state of each cut-off device RB according to control commands from the GCU100. The cut-off device RB can be an electromagnetic mechanical relay. The cut-off device RB can also be configured to be manually on / off by the user.

[0063] In this embodiment, the box Cg is configured to be detachable from the power circuit SUB. For example, the user can remove the box Cg from the power circuit SUB even when the cutters RB1 and RB2 are both in the open state (off state). The battery string St can operate even with empty boxes, so the user can easily increase or decrease the number of boxes Cg contained in the battery string St. Such a battery string St is suitable for battery reuse.

[0064] In the housing Cg, the monitoring unit BS is configured to detect the state of battery B (e.g., voltage, current, and temperature) and output the detection results to the SCU. The monitoring unit BS includes a voltage sensor for detecting the voltage of battery B, a current sensor for detecting the current of battery B, and a temperature sensor for detecting the temperature of battery B. Alternatively, the monitoring unit BS may also be a BMS (Battery Management System) with SOC estimation, SOH (State of Health) estimation, battery voltage equalization, diagnostic functions, and communication functions, in addition to the aforementioned sensor functions. The SCU obtains the state of each battery B (e.g., temperature, current, voltage, SOC, and internal resistance) based on the output of each monitoring unit BS and outputs the obtained state of each battery B to the GCU100. It should be noted that SOC (State Of Charge) represents the remaining charge capacity, for example, expressed as the ratio of the current charge capacity to the charge capacity at full charge, ranging from 0% to 100%.

[0065] The battery circuit modules M contained in the battery string St are connected by a common wire PL. The wire PL includes the output terminals OT1 and OT2 of each battery circuit module M. The battery circuit modules M contained in the battery string St are connected to each other through the output terminal OT2 of the battery circuit module M and the output terminal OT1 of the adjacent battery circuit module M.

[0066] The power circuit SUB includes a first switching element 51 (hereinafter referred to as "SW51"), a second switching element 52 (hereinafter referred to as "SW52"), a first diode 53, a second diode 54, a choke coil 55, a capacitor 56, and output terminals OT1 and OT2. Each of SW51 and SW52 is driven by a drive circuit SUB. In this embodiment, SW51 and SW52 correspond to examples of the "first switch" and "second switch" of this disclosure, respectively.

[0067] A SW51, a capacitor 56, and a battery B are connected in parallel between the output terminals OT1 and OT2 of the power circuit SUB. SW51 is located on wire PL and is configured to switch the connection state (on / off) between output terminals OT1 and OT2. Output terminal OT1 is connected to the positive terminal of battery B via wire BL1, and output terminal OT2 is connected to the negative terminal of battery B via wire BL2. Cut-off devices RB1 and RB2 are respectively located on wires BL1 and BL2. SW52 and a choke coil 55 are also located on wire BL1. In the battery circuit module M, when SW52, connected in series with battery B, is in the on state (conducting state) and SW51, connected in parallel with battery B, is in the off state (disconnecting state), the voltage of battery B is applied between output terminals OT1 and OT2.

[0068] A capacitor 56 is provided between the output terminals OT1 and OT2 and the battery B, and is connected to wires BL1 and BL2 respectively. One end of the capacitor 56 is connected to wire BL1 between SW52 and choke coil 55. The capacitor 56 smooths the voltage of the battery B and outputs it between the output terminals OT1 and OT2.

[0069] SW51 and SW52 are each, for example, FETs (Field-Effect Transistors). First diode 53 and second diode 54 are connected in parallel with respect to SW51 and SW52, respectively. SW52 is located between the output terminal OT1 and the choke coil 55. The choke coil 55 is located between SW52 and the positive terminal of battery B. Battery B, choke coil 55, and capacitor 56 form an RLC filter. This RLC filter aims to average the current. It should be noted that SW51 and SW52 are not limited to FETs; they can also be switches other than FETs.

[0070] The SCU sends signals to the drive circuit SUA to drive SW51 and SW52 according to instructions from the GCU100. Specifically, the SCU generates a gate signal according to control instructions from the GCU100. This gate signal is equivalent to the signal used to drive SW51 and SW52 according to instructions from the GCU100. The SCU then sends the gate signal to the drive circuit SUA. The drive circuit SUA includes a GD (gate driver) 81 that drives SW51 and SW52 according to the gate signal and a delay circuit 82 that delays the gate signal. The SW51 and SW52 included in the battery circuit module M are each turned on / off according to the gate signal.

[0071] Figure 3 This is a timing diagram illustrating an example of the operation of the battery circuit module M controlled by a gate signal. In this embodiment, a rectangular wave signal is used as the gate signal for driving SW51 (first switch) and SW52 (second switch). Figure 3 The "Low" and "High" gate signals shown represent the L level and H level of the gate signal (rectangular wave signal), respectively. Additionally, "output voltage" refers to the voltage output between output terminals OT1 and OT2.

[0072] In the initial state of battery circuit module M, no gate signal is input to drive circuit SUA (gate signal = L level), and SW51 and SW52 are in the on and off states, respectively. If a gate signal is input to drive circuit SUA, GD81 drives SW51 and SW52 according to the input gate signal. Figure 3 In the example shown, at time t1, the gate signal rises from level L to level H, and simultaneously with the rise of the gate signal, SW51 switches from the ON state to the OFF state. Furthermore, at time t2, which is a predetermined time delay (hereinafter referred to as "dt1") from the rise of the gate signal, SW52 switches from the OFF state to the ON state. Thus, the battery circuit module M becomes operational. Hereinafter, the period from the rise of the gate signal to the passage of dt1 will also be referred to as the "first delay period".

[0073] Figure 4 This is a diagram showing the battery circuit module M in its operating state. (Refer to...) Figure 4 In the battery circuit module M in operation, with SW51 in the off state and SW52 in the on state, the voltage of battery B is applied between output terminals OT1 and OT2. The voltage of battery B is applied between output terminals OT1 and OT2 via capacitor 56, and voltage Vm is output between output terminals OT1 and OT2.

[0074] Refer again Figure 3 At time t3, if the gate signal drops from H level to L level, SW52 switches from the ON state to the OFF state simultaneously with the drop in the gate signal. This puts the battery circuit module M into a stopped state. In the stopped state of the battery circuit module M, SW52 is in the OFF state, and the voltage of battery B is no longer applied between output terminals OT1 and OT2. Then, at time t4, which is a predetermined time delay (hereinafter referred to as "dt2") from the drop in the gate signal, SW51 switches from the OFF state to the ON state. dt1 and dt2 can be the same or different. In this embodiment, dt1 and dt2 are each set to 100n seconds. However, dt1 and dt2 can be arbitrarily set.

[0075] Hereinafter, the period from the fall of the gate signal to the passage of dt2 will also be called the "second delay period". In addition, the period from the end of the second delay period to the battery circuit module M entering the working state will also be called the "stop period".

[0076] Figure 5 This is a diagram showing the state of battery circuit module M during the delay period. (Example) Figure 5 As shown, during both the first and second delay periods, SW51 and SW52 are in a disconnected state.

[0077] Figure 6 This is a diagram showing the state of battery circuit module M during the shutdown period. (Example) Figure 6 As shown, during the stop period, SW51 becomes the ON state and SW52 becomes the OFF state, just like in the initial state.

[0078] Regardless of whether it is during the aforementioned delay period or the stop period, the battery circuit module M is in a stopped state. In the stopped state, no voltage is applied between the output terminals OT1 and OT2. By setting the first delay period and the second delay period, it is possible to prevent SW51 and SW52 from simultaneously becoming on (i.e., the battery circuit module M becoming short-circuited).

[0079] The battery string St is configured to output a voltage from 0V up to the sum of the voltages of the individual batteries B within the battery string St. In the scanning unit SU, the scanning control unit (SCU) controls the output voltage of the battery string St by adjusting the number of battery circuit modules M that are simultaneously in operation. In this embodiment, the SCU controls the voltage of the battery string St through scanning control.

[0080] Figure 7 This is a diagram used to illustrate an example of scan control. (and) Figure 2 and Figure 3 Refer to together Figure 7 In the battery string St under scanning control, a specified number (in Figure 7 In the example shown, three batteries B are connected to the circuit, while the other batteries B are disconnected from the circuit. In battery circuit module M, if SW51 is in the off state and SW52 is in the on state, battery B is connected to the circuit, and its voltage is applied to the circuit. In battery circuit module M, if SW51 is in the on state and SW52 is in the off state, battery B is disconnected from the circuit, and its voltage is no longer applied to the circuit (passes through). In the scan control, while swapping the batteries B connected to the circuit, a predetermined number (in...) are maintained. Figure 7 The example shown depicts three batteries (B) simultaneously connected to the circuit. The scanning unit SU, through one side... Figure 3The gate signal delay shown is used to transmit the gate signal from one end (upstream) of the battery string St to the other end (downstream) to perform scan control. The gate signal is delayed by the delay circuit 82. Furthermore, GD81 drives SW51 and SW52 according to the gate signal. Therefore, the downstream battery B is connected to the circuit later than the upstream battery B. For example, as... Figure 7 As shown, the current and SOC of each battery B in the battery string St are equalized by connecting each battery B in the battery string St sequentially. It should be noted that the delay time of each delay circuit 82 is set by the GCU100. The delay time may be set to 0 (no delay). For example, in the scanning unit SU, if the delay time of all delay circuits 82 is set to 0, then the connection / passing of all batteries B is performed at the same timing.

[0081] The GCU100 can also control the input and output of the battery string St based on the period and duty cycle (the ratio of the H-level period to the period) of the gate signal. The GCU100 can select connection / disconnection for each cell Cg (battery B) in the battery string St. The disconnection instruction is sent from the GCU100 to the SCU. The GD81, which is instructed to disconnect from the SCU, can maintain the corresponding battery B in a through state regardless of the gate signal. Alternatively, the SCU can disconnect a battery B from the circuit by turning off cutters RB1 and RB2. The GCU100 can also adjust the load sharing of each battery B based on its capacity (or SOC). The GCU100 can also prevent the discharge or charging of specific batteries B based on their SOC. For example, the GCU100 can prevent the discharge of batteries B that are likely to be over-discharged, or prevent the charging of batteries B that are likely to be over-charged. Furthermore, the GCU100 can perform constant load-based degradation diagnosis for specified batteries B in the battery string St. The GCU100 can also keep battery B disconnected from the circuit by prohibiting its use (or battery B with severe degradation). (See reference) Figure 6 ).

[0082] Figure 1The first power supply circuit 2 and the second power supply circuit 3 shown each have a number of the aforementioned scanning units SU corresponding to the number of battery strings. Specifically, the first power supply circuit 2 includes three scanning units SU (hereinafter referred to as "SU1", "SU2", and "SU3") corresponding to battery strings St1 to St3. SCU12, 22, and 32 together with battery strings St1, St2, and St3 respectively constitute SU1, SU2, and SU3. The battery strings, drive circuit, and SCUs of the scanning units SU included in the first power supply circuit 2 are respectively equivalent to an example of the "DC battery string", "first drive circuit", and "first control circuit" of this disclosure. The second power supply circuit 3 includes six scanning units SU (hereinafter referred to as "SU4" to "SU9") corresponding to battery strings St4 to St9. SCU41, 42, 43, 44, 45, and 46 together with battery strings St4, St5, St6, St7, St8, and St9 respectively constitute SU4, SU5, SU6, SU7, SU8, and SU9. The battery string, drive circuit, and SCU of the scanning unit SU included in the second power circuit 3 are respectively equivalent to an example of the "AC battery string", "second drive circuit", and "second control circuit" of this disclosure.

[0083] By controlling SU1 to SU3, GCU100 can enable each of battery strings St1 to St3 to output DC power (constant voltage power) at a desired voltage. GCU100 can determine the output voltage (DC power voltage) of each of battery strings St1 to St3 based on information obtained from the user or server 200. By controlling SU4 to SU9, GCU100 can enable each of battery strings St4 to St9 to output AC power (power with periodically changing voltage magnitude) with a desired voltage waveform. GCU100 can determine the output voltage waveform of each of battery strings St4 to St9 based on information obtained from the user or server 200. The user can also input power supply conditions and / or charging conditions to GCU100.

[0084] In this embodiment, each DC battery (battery B) included in the DC battery strings (battery strings St1, St2, and St3) is a high-output type battery. Specifically, each DC battery is a nickel-metal hydride secondary battery with a power density of 1500 W / kg or more and less than 5000 W / kg and an energy density of 50 Wh / kg or more and less than 500 Wh / kg. Furthermore, each AC battery (battery B) included in the AC battery strings (battery strings St4 to St9) is a high-capacity type battery. Specifically, each AC battery is a lithium-ion secondary battery with a power density of 300 W / kg or more and less than 1000 W / kg and an energy density of 500 Wh / kg or more and less than 1000 Wh / kg. However, different types of lithium-ion secondary batteries are used in battery strings St4, St6, and St8, and battery strings St5, St7, and St9. Each battery B included in battery strings St4, St6, and St8 is a ternary lithium-ion secondary battery (NMC). In addition, each battery B included in battery strings St5, St7 and St9 uses lithium-ion secondary batteries based on iron phosphate (LFP).

[0085] However, the types (e.g., construction and materials) and characteristics (e.g., power density and energy density) of batteries are not limited to those described above and can be appropriately varied. For example, sometimes power-type (high-output) batteries and energy-type (high-capacity) batteries are defined based on a Ragone diagram with power density (W / kg) on ​​the vertical axis and energy density (Wh / kg) on ​​the horizontal axis. Batteries classified as high-output in the Ragone diagram can also be used as DC batteries, and batteries classified as high-capacity in the Ragone diagram can be used as AC batteries. Furthermore, multiple types of rechargeable batteries can be mixed in a single battery string. The battery can also be a lithium-air battery, a lead-acid battery, a NAS (lithium-sulfur) battery, a redox flow battery, or an all-solid-state battery. Additionally, battery B can be manufactured by reusing rechargeable batteries used in xEVs by connecting them in series.

[0086] In the first power supply circuit 2, the DC power output from battery strings St1, St2, and St3 is input to converters 11, 21, and 31, respectively. Hereinafter, [the following will be used...] Figure 1 and Figure 8 The structure of the converter included in the first power supply circuit 2 will now be described. Converters 11, 21, and 31 have the same structure, therefore, the structure of converter 11 will be described as representative below.

[0087] Figure 8 This is a diagram showing the structure of the converter 11 included in the first power supply circuit 2. (And...) Figure 1 Refer to together Figure 8 The converter 11 is a three-phase converter, with switching elements q1 and q2 connected in series in the U-phase arm, switching elements q3 and q4 connected in series in the V-phase arm, and switching elements q5 and q6 connected in series in the W-phase arm. Diodes d1 to d6 are connected in anti-parallel between the collectors and emitters of the switching elements q1 to q6, respectively. In this embodiment, the converter 11 is a three-phase converter previously used to drive a three-phase synchronous motor for xEV. The converter 11 is configured to enable bidirectional power conversion.

[0088] The midpoints of each phase arm of converter 11 are connected to the insulation filter T1, and are also connected to the wire PGL (see reference) via relay R1 and distribution board C1. Figure 1 The switching elements q1 to q6 of converter 11 are controlled by control commands from GCU100. Each switching element of converter 11 is turned on / off, for example, by PWM (Pulse Width Modulation).

[0089] Converter 11 converts the DC power output from battery string St1 into AC power (three-phase AC power) and supplies it to the power line PGL. Converter 11 functions as a DC / AC conversion circuit. The AC power output from converter 11 is supplied to the power line PGL after passing through insulation filter T1, relay R1, and distribution board C1. SU1 can output power from any battery B among the multiple batteries B contained in battery string St1 by controlling SW51 and SW52 of each battery circuit module M contained in battery string St1. For example, SU1 outputs power from a designated battery B to converter 11 according to instructions from GCU100. In SU2 and SU3, power is also output from batteries B contained in battery strings St2 and St3 to converters 21 and 31, respectively, in the same manner as described above. GCU100 is configured to send commands for controlling battery strings St1, St2 and St3 to SCU12, 22 and 32 and control converters 11, 21 and 31 by outputting three-phase AC power from the first power supply circuit 2.

[0090] Converter 11 converts the AC power (three-phase AC power) input from the power system PG through the power line PGL, distribution board C1, relay R1, and insulation filter T1 into DC power and outputs it to the battery string St1. SU1 can use the DC power supplied from converter 11 to charge the battery B in the battery string St1. At this time, GCU 100 controls SU1 so that the voltage of the battery string St1 is slightly lower than the AC voltage supplied from the power system PG. SU1 can charge any one of the multiple batteries B in the battery string St1 by controlling SW51 and SW52 of each battery circuit module M included in the battery string St1. For example, SU1 charges a designated battery B according to instructions from GCU 100. In SU2 and SU3, the batteries B included in the battery strings St2 and St3 are charged in the same way as described above. GCU100 is configured to send instructions for controlling battery strings St1, St2 and St3 to SCU12, 22 and 32 and control converters 11, 21 and 31 in a manner that allows the specified batteries B contained in battery strings St1, St2 and St3 to be charged.

[0091] like Figure 1 As shown, converters 11, 21, and 31 are connected in parallel with respect to the isolation filter T1. Specifically, the midpoint of each phase arm of converters 11, 21, and 31 (refer to...) Figure 8 The first power supply circuit 2 is connected to the insulation filter T1 via wires. It uses parallel-connected battery strings St1, St2, and St3 and converters 11, 21, and 31 to output three-phase AC power (first AC power). In this embodiment, the first power supply circuit 2 includes three parallel-connected DC battery strings (battery strings St1, St2, and St3). Increasing the number of parallel-connected DC battery strings makes it easier to stabilize the AC power waveform output from the first power supply circuit 2. However, the number of DC battery strings included in the first power supply circuit 2 is not limited to three; it can be varied appropriately, and may include one or more than four. The first power supply circuit 2 can also be configured to output single-phase AC power.

[0092] Figure 9 This is a diagram showing the structure of the second power supply circuit 3. (Refer to...) Figure 9 Battery strings St4, St5, St6, St7, St8, and St9 correspond to the battery strings for the first U phase, the second U phase, the first V phase, the second V phase, the first W phase, and the second W phase, respectively.

[0093] The positive terminals of battery strings St4 and St5 are connected to wire PLU. The positive terminals of battery strings St6 and St7 are connected to wire PLV. The positive terminals of battery strings St8 and St9 are connected to wire PLw. Additionally, the negative terminals of each of battery strings St4 through St9 are connected to the neutral point N1. In the second power supply circuit 3, the parallel-connected battery strings St4 and St5, St6 and St7, and St8 and St9 are Y-connected.

[0094] SCU41-46 utilize control commands from GCU100 to... Figure 2 The SW51 and SW52 of each battery circuit module M shown are controlled by a switching frequency of tens of kHz to adjust the series voltage (output voltage) of each battery string St4 to St9 to become... Figure 9 The voltage waveform shown below is used for control. Figure 9 In the diagram, line L11 represents the series voltage of the battery strings (battery strings St4 and St5) for phase U. Line L12 represents the series voltage of the battery strings (battery strings St6 and St7) for phase V. Line L13 represents the series voltage of the battery strings (battery strings St8 and St9) for phase W. Lines L11, L12, and L13 are sine waves with a 120° phase shift, and their frequency corresponds to the frequency of the power system PG (e.g., 60Hz).

[0095] The series voltages of battery strings St4 to St9 are controlled as described above, and the line-to-line voltages of wires PLU, PLV, and PLW become... Figure 9 The voltage waveform shown above. Figure 9 In the diagram, line L21 represents the voltage "Vuv" between wires Plu and Plv, line L22 represents the voltage "Vwu" between wires PLw and Plu, and line L23 represents the voltage "Vvw" between wires PLv and PLw. Each voltage is a sinusoidal alternating current waveform with its polarity (positive / negative) changing periodically.

[0096] As described above, the second power supply circuit 3 uses battery strings St4 to St9 to output three-phase AC power (second AC power). In the second power supply circuit 3, the battery strings for the U phase (battery strings St4 and St5), the battery strings for the V phase (battery strings St6 and St7), and the battery strings for the W phase (battery strings St8 and St9) are connected by a Y-connection, enabling the second power supply circuit 3 to output AC power (more specifically, three-phase AC power) without the use of an inverter. This reduces costs. In this embodiment of the second power supply circuit 3, multiple battery strings are connected in parallel as AC battery strings for each phase. The more parallel the number of AC battery strings, the easier it is to finely adjust the AC power waveform output from the second power supply circuit 3. However, the number of AC battery strings included in the second power supply circuit 3 is not limited to 6; it can be varied appropriately, and may also be 3 or even 1. Furthermore, the second power supply circuit 3 can also be configured to output single-phase AC power.

[0097] The AC power output from the first power supply circuit 2 is supplied to the power line PGL via the insulation filter T1, relay R1, and distribution board C1. The AC power output from the second power supply circuit 3 is supplied to the power line PGL via the insulation filter T2, relay R2, and distribution board C1. The power supply system 1 is configured such that, during system cooperative operation, three-phase AC power is supplied to the power system PG from at least one of the first power supply circuit 2 and the second power supply circuit 3 in reverse flow.

[0098] Each of the insulation filters T1 and T2 includes, for example, an LCL filter and a three-phase transformer. Each of the insulation filters T1 and T2 utilizes an LCL filter to reduce noise components in the three-phase AC power, and uses a three-phase transformer to convert the three-phase AC power to a specified voltage (e.g., 200V) and provides insulation between the input and output sides. In this embodiment, each of the converters 11, 21, and 31 is a reused product used for other purposes (xEV drive), and its performance may not be high. Therefore, noise is easily included in the output of these converters. The insulation filter T1, disposed between the first power supply circuit 2 and the wire PGL, is configured to remove such noise. The insulation filter T1 may also have higher noise removal performance than the insulation filter T2.

[0099] Relays R1 and R2 are each, for example, electromagnetic mechanical relays. GCU100 is configured to switch the connection (parallel connection) / disconnection (splitting) of the first power supply circuit 2 with the power system PG by controlling the on / off state of relay R1. Furthermore, GCU100 is configured to switch the connection (parallel connection) / disconnection (splitting) of the second power supply circuit 3 with the power system PG by controlling the on / off state of relay R2.

[0100] Distribution board C1 supplies power from the power system PG to the first power circuit 2 and the second power circuit 3 respectively. Additionally, distribution board C1 supplies power from at least one of the first power circuit 2 and the second power circuit 3 to the power system PG and / or building 300 (distribution board C2). The AC power output from the first power circuit 2 and the second power circuit 3, together with the AC power output from the power system PG, is supplied to the wiring PGL, and then to the wiring within building 300 via distribution board C2.

[0101] The power supply system 1 is configured to perform a first output that outputs AC power (first AC power) only from the first power circuit 2 of the first power circuit 2 and the second power circuit 3, a second output that outputs AC power (second AC power) only from the second power circuit 3, and a dual output that outputs AC power (first AC power and second AC power) from both. In the dual output, the first power circuit 2 and the second power circuit 3 simultaneously output AC power. Furthermore, the power supply system 1 is configured to perform a first input that inputs AC power only to the first power circuit 2 of the first power circuit 2 and the second power circuit 3, a second input that inputs AC power only to the second power circuit 3, and a dual input that inputs AC power to both. In the dual input, AC power is simultaneously input to the first power circuit 2 and the second power circuit 3. In this embodiment, the GCU 100 selects and executes any one of the following: the first output, the second output, the dual output, the first input, the second input, and the dual input.

[0102] GCU100 is configured to switch between a first output, a second output, and both outputs. GCU100 is also configured to switch between a first input, a second input, and both inputs. During the execution of the first output or first input, GCU100 turns relay R1 on and relay R2 off. During the execution of the second output or second input, GCU100 turns relay R1 off and relay R2 on. During the execution of both outputs or both inputs, GCU100 turns both relays R1 and R2 on. When neither the first power supply circuit 2 nor the second power supply circuit 3 is performing any input or output, GCU100 turns both relays R1 and R2 off.

[0103] The GCU100 is configured to perform degradation diagnostics on each of the batteries B in the DC battery strings (battery strings St1 to St3) and the AC battery strings (battery strings St4 to St9). In this embodiment, degradation diagnostics are performed on batteries B that have been in existence for a predetermined period of time since the last diagnostic. Degradation diagnostics can be performed on multiple batteries B simultaneously, or on each battery B one by one sequentially.

[0104] Hereinafter, the battery B, which will be the target of degradation diagnosis by GCU100, is referred to as the "diagnostic object". GCU100 is configured to perform degradation diagnosis on the diagnostic object using data (hereinafter also referred to as "diagnostic data") obtained successively during at least one of the charging and discharging processes of the diagnostic object. The diagnostic data may include the voltage and current changes of the diagnostic object during the charging or discharging process. In addition, the diagnostic data may also include the temperature changes of the diagnostic object during the charging or discharging process. GCU100 can use the diagnostic data to determine at least one of the full-charge capacity and internal resistance of the diagnostic object. GCU100 can also determine the internal resistance of the diagnostic object based on the relationship between battery voltage and battery current obtained as diagnostic data. In addition, GCU100 can also determine the full-charge capacity of the diagnostic object based on the battery voltage when the diagnostic object is charged from an empty state to a fully charged state at a certain rate. In addition, GCU100 can also improve the accuracy of determining the full-charge capacity and internal resistance of the diagnostic object by using battery temperature.

[0105] Figure 10 This is a flowchart illustrating a first example of the process involved in battery degradation diagnosis performed by the GCU100. The process shown in this flowchart begins when diagnostic preparation is complete for battery B (the diagnostic target) at a predetermined diagnostic timing. The predetermined diagnostic timing can be a time elapsed since the last diagnostic was performed. The GCU100 can connect the diagnostic target to a circuit (e.g., see reference...). Figure 4 If the SOC of the diagnostic object falls within a specified range (e.g., below a specified SOC value), the diagnostic preparation is considered complete. Hereinafter, each step in the flowchart will be abbreviated as "S".

[0106] and Figure 1 and Figure 2 Refer to together Figure 10 In S11, GCU100 uses power supplied from the power system PG to charge the diagnostic object at a specified rate C. The specified rate C can be a small current that does not affect the supply and demand balance of the power system PG. The charging current is adjusted, for example, by a charging command sent from GCU100 to the object SU (any of SU1 to SU9 corresponding to the diagnostic object).

[0107] Next, the GCU100 acquires diagnostic data in S12. Specifically, the current, voltage, and temperature of the object being diagnosed during the charging process are monitored by the monitoring unit BS ( Figure 2The detected diagnostic data is saved to the storage device of GCU100. In the next step, S13, GCU100 determines whether the acquisition of diagnostic data used in the diagnosis has been completed. If the acquisition of diagnostic data has not been completed (not in S13), GCU100 determines in S14 whether the diagnostic object is connected to the circuit. GCU100, for example, based on SW52 (which switches the connection / disconnection of the diagnostic object to the circuit),... Figure 2 The GCU100 determines whether the diagnostic object is connected to the circuit based on the state of SW52. Specifically, GCU100 determines that the diagnostic object is connected to the circuit when SW52 is in the ON state, and determines that the diagnostic object is disconnected from the circuit when SW52 is in the OFF state. Details will be described later. In this embodiment, sometimes battery B in the degradation diagnosis is disconnected from the circuit (see [reference]). Figure 14 (S105).

[0108] If the diagnostic object is connected to the circuit (yes in S14), the process returns to S11. During the period when diagnostic data acquisition is not complete and the diagnostic object is connected to the circuit (no in S13 and yes in S14), charging and diagnostic data acquisition (S11 and S12) continue, and the current, voltage, and temperature of the diagnostic object during the charging process are detected and saved sequentially. On the other hand, if the diagnostic object is disconnected from the circuit (no in S14), the GCU100 sends a command to the object SU in S15 to stop charging the diagnostic object. The GCU100 remains in a standby state with the charging of the diagnostic object interrupted until the diagnostic object is reconnected to the circuit (S14 and S15). Furthermore, if the diagnostic object is reconnected to the circuit (yes in S14), the GCU100 restarts charging the diagnostic object and acquiring diagnostic data (S11 and S12).

[0109] If the acquisition of diagnostic data is complete (yes in S13), then in S16, GCU100 performs a degradation diagnosis of the diagnostic object using the diagnostic data acquired sequentially during charging. Specifically, GCU100 calculates at least one of the aforementioned full-charge capacity and internal resistance for the diagnostic object. Through the processing in S16, Figure 10 The series of processes shown has ended.

[0110] Figure 11 This is a flowchart illustrating a second example of the processes involved in battery degradation diagnosis performed by the GCU100. The processes shown in this flowchart begin when diagnostic preparation is complete for battery B (the diagnostic target) at a predetermined diagnostic timing. The GCU100 can connect the diagnostic target to a circuit (e.g., see reference...). Figure 4 If the SOC of the diagnostic subject falls within a specified range (e.g., a range above a specified SOC value), the diagnostic preparation is considered complete.

[0111] Figure 11 The treatment shown replaces S11 and S15 ( Figure 10 In addition to adopting S11A and S15A, it also uses S11A and S15A. Figure 10 The processing is the same. In S11A, GCU100 discharges the object under diagnosis at a predetermined rate C. The predetermined rate C can be a small current that does not affect the supply and demand balance of the power system PG. The discharge current is adjusted, for example, by a discharge command sent from GCU100 to the object SU. Furthermore, in S15A, GCU100 sends a command to the object SU to stop the discharge of the object under diagnosis. And, in S16, GCU100 uses diagnostic data acquired sequentially during the discharge process to perform a degradation diagnosis of the object under diagnosis.

[0112] In this embodiment, GCU100 is configured to perform... Figure 10 The processing and Figure 11 The processing is shown for both sides. For example, when performing degradation diagnostics in parallel with energy management, the GCU100 can switch according to the direction of the energy management current (charging / discharging). Figure 10 The processing and Figure 11 The processing is shown. Additionally, the GCU100 can switch based on the SOC of the diagnostic object at the start of the diagnostic process. Figure 10 The processing and Figure 11 The processing shown is described. The GCU100 can also perform degradation diagnosis with high accuracy using two types of diagnostic results (charge / discharge). Additionally, the GCU100 can also... Figure 11 After determining the internal resistance of the diagnostic object through the process shown, by... Figure 10 The process shown is used to determine the full charge capacity of the diagnostic object. However, it is not limited to this; the GCU100 can also be configured to only perform... Figure 10 The processing and Figure 11 One of the processes shown.

[0113] Figure 1 The server 200 shown requests power adjustments from the power system PG to the users of the power system 1 as needed. The server 200 may also implement demand response (DR). In this embodiment, the server 200 requests any of the following: FCR, S-FRR, FRR, RR, RR-FIT.

[0114] Figure 12 This diagram illustrates one example of the types and details of power regulation. (See reference...) Figure 12 Power companies (TSOs) can, in the supply and demand adjustment market, adjust the price of electricity equivalent to the power system PG (Power Generation System). Figure 1Bidders shall submit bids for at least one of the following adjustment forces: FCR, S-FRR, FRR, RR, and RR-FIT, and the power adjustment force shall be adapted to the requirements of the winning bidder for the winning user.

[0115] FCR stands for Frequency Containment Reserve, which adjusts the very short-cycle component (cyclic part), also known as "primary adjustment force". Regarding FCR, the response time is within 10 seconds, and the duration is 5 minutes. FCR is executed via local control (offline). Response time is the time required from receiving a command to outputting power according to the command.

[0116] S-FRR is the Synchronized Frequency Restoration Reserve for adjusting the short-period component (edge ​​portion). FRR is the Frequency Restoration Reserve for adjusting the long-period component (permanent portion). S-FRR and FRR are collectively referred to as "secondary adjustment forces." Both S-FRR and FRR are executed remotely. The response time for both S-FRR and FRR is within 5 minutes, and the duration is 30 minutes. In the remote control of S-FRR, the LFC (Load Frequency Control) signal is used, with a command interval of 0.5 seconds to tens of seconds. In the remote control of FRR, the EDC (Economic Load Dispatching Control) signal is used, with a command interval of 1 minute to several minutes.

[0117] RR stands for Replacement Reserve, used to adjust the long-period component (persistent portion). RR-FIT is the Replacement Reserve for Feed-in Tariff used in FIT. RR and RR-FIT are collectively referred to as "triple adjustment forces." RR and RR-FIT are each executed remotely. For RR, the response time is within 15 minutes, and the duration is 3 hours. In the remote control of RR, EDC signals are used, with command intervals of 1 minute to several minutes. For RR-FIT, the response time is within 45 minutes, and the duration is 3 hours. In the remote control of RR-FIT, supply and demand adjustment commands used to compensate for output prediction errors in renewable energy (the error between predicted and actual values) are sent via dedicated lines or a simplified command system, with command intervals of 30 minutes.

[0118] When server 200 requests power adjustment (energy management) from a user who has won a bid for adjustment capacity in the supply and demand adjustment market, a power adjustment request signal (hereinafter also referred to as the "DR signal") is sent from server 200 to the user terminal. The DR signal indicates the content of the power adjustment (energy management) requested from server 200. In this embodiment, the DR signal includes the type of power adjustment (in this embodiment, any one of FCR, S-FRR, FRR, RR, RR-FIT), the control method (e.g., local control / remote control), the adjustment period (indicating the start and end times of the adjustment), the power adjustment magnitude (ΔkW), the requested duration, and the requested response time.

[0119] The DR signal is stored in the storage device of GCU100. The user terminal can be an in-vehicle terminal, a user-carried mobile terminal, or GCU100. Examples of mobile terminals include laptops, smartphones, wearable devices, electronic keys, and service tools. In the case where the user terminal is an in-vehicle terminal or a mobile terminal, the user terminal that receives the DR signal from server 200 sends the DR signal to GCU100. GCU100 then stores the DR signal in the storage device.

[0120] When the adjustment force is a 2-fold or 3-fold adjustment force (any of S-FRR, FRR, RR, RR-FIT), the server 200 initiates remote control (i.e., command transmission) of the GCU100 at the timing when the aforementioned adjustment start time arrives. In the remote control, the input and output power of at least one of the first power supply circuit 2 and the second power supply circuit 3 is controlled by commands from the server 200 in a manner that performs power adjustment of the power system PG.

[0121] When the adjustment force is a single adjustment force (FCR), GCU100 begins local control at the timing when the aforementioned adjustment start time arrives. In this local control, GCU100 controls the input and output power of at least one of the first power supply circuit 2 and the second power supply circuit 3 based on the detection values ​​of the power sensors C1a, C1b and C1c, in a manner that suppresses frequency variations in the power supplied by the power system PG to the building 300.

[0122] Figure 13 This is a flowchart illustrating an example of the processing involved in power conditioning (energy management) performed by the GCU100. The processing shown in this flowchart begins, for example, when a new DR signal is added to the GCU100's storage device. However, it is not limited to this; it can also be timed back a predetermined time (e.g., a time selected from a range of 5 minutes to 3 hours) from the start time of the conditioning indicated by the DR signal. Figure 13 The series of processes shown begins.

[0123] and Figure 1 and Figure 2 Refer to together Figure 13 In S21, GCU100 selects one or more target batteries from the multiple batteries B contained in the DC battery string (battery string St1 to St3) and the AC battery string (battery string St4 to St9) to perform the required power adjustment. Figure 14 This is a flowchart showing the details of S21 (selection of target battery).

[0124] and Figure 1 and Figure 2 Refer to together Figure 14 First, in S101 and S102, GCU100 determines whether the power change of the requested power adjustment is suitable for degradation diagnosis. Specifically, in S101, GCU100 determines whether the required duration is above a first reference value (hereinafter referred to as "Th1") based on the DR signal. Th1 represents the boundary value (lower limit) of the duration for which the power change is slow enough to perform degradation diagnosis with respect to power adjustment. In S102, GCU100 determines whether the required response time is below a second reference value (hereinafter referred to as "Th2"). Th2 represents the boundary value (upper limit) of the response time for which the power change is drastic enough to make degradation diagnosis impossible with respect to power adjustment. For example, values ​​determined by the user through experiments can be set as Th1 and Th2. In this embodiment, Th1 and Th2 are set to 2 hours and 10 minutes, respectively. However, Th1 and Th2 can be appropriately changed.

[0125] If the required duration is Th1 or longer (yes in S101), GCU100 determines that the power change of the required power adjustment is small (suitable for degradation diagnosis). If the determination is no in S101, the process proceeds to S102. If the required response time is Th2 or shorter (yes in S102), GCU100 determines that the power change of the required power adjustment is large (not suitable for degradation diagnosis). If the determination is no in both S101 and S102, GCU100 determines that the power change of the required power adjustment is small (suitable for degradation diagnosis).

[0126] If the power fluctuation required for the requested power adjustment is determined to be large (unsuitable for degradation diagnosis), the process proceeds to S104 after step S103. In this embodiment, if the required power adjustment is a single or double adjustment (FCR, S-FRR, or FRR), the process proceeds to S103. If the power fluctuation required for the requested power adjustment is determined to be small (suitable for degradation diagnosis), the process proceeds to S104 without stepping to S103. In this embodiment, if the required power adjustment is a triple adjustment (RR or RR-FIT), the process proceeds to S104 without stepping to S103.

[0127] In S103, GCU100 excludes batteries from the selected candidates for the degradation diagnosis. Specifically, Figure 10 or Figure 11 The diagnostic object in the process shown is excluded from the candidate of the object battery. Then, the process proceeds to S104.

[0128] In this embodiment, only batteries undergoing degradation diagnosis are excluded from the candidate list of target batteries. However, this is not a limitation; in addition to batteries undergoing degradation diagnosis, specified batteries may also be excluded from the candidate list of target batteries. For example, batteries with a high degree of degradation may be excluded from the candidate list of target batteries. Alternatively, batteries whose State of Charge (SOC) deviates from a specified range (e.g., 30% to 70%) may be excluded from the candidate list of target batteries.

[0129] In S104, GCU100 selects the target battery for performing the requested power adjustment based on the type and conditions of power adjustment indicated by the DR signal. Essentially, all batteries B included in the first power supply circuit 2 and the second power supply circuit 3 become candidates for target batteries. However, batteries excluded in S103 are not selected as target batteries.

[0130] The GCU100 can also determine the target battery based on the type of power regulation required. For example, the GCU100 can select only DC batteries as the target battery corresponding to primary regulation (FCR). The GCU100 can select all DC batteries included in the candidate target batteries as the target battery, or select a specified number of DC batteries as the target battery. Additionally, the GCU100 can select only AC batteries as the target battery corresponding to secondary regulation (S-FRR or FRR). The GCU100 can select all AC batteries included in the candidate target batteries as the target battery, or select a specified number of AC batteries as the target battery. Furthermore, the GCU100 can select both DC and AC batteries as the target battery corresponding to tertiary regulation (RR or RR-FIT). The GCU100 can select all DC and AC batteries included in the candidate target batteries as the target battery, or select a specified number of DC and AC batteries as the target battery. When selecting a specified number of batteries from the candidate target batteries, the GCU100 can prioritize batteries with lower degradation levels.

[0131] In S105, GCU100 disconnects batteries B other than the target battery (i.e., the batteries B not selected in S104) from the circuit. Specifically, GCU100 disconnects battery B from the circuit by turning SW51 on and turning SW52 off (see reference). Figure 6 In S105, each battery B disconnected from the circuit remains in the disconnected state (passing state) until the required power adjustment is completed. Regarding the batteries (diagnostic targets) excluded from the candidate battery list in S103, in... Figure 10 S14 and S15 (or Figure 11 The degradation diagnosis in S14 and S15A was interrupted. After the processing in S105 was executed, Figure 14 The series of processes shown has ended, and processing has begun. Figure 13 S22.

[0132] Again with Figure 1 and Figure 2 Refer to together Figure 13 In S22, GCU100 determines whether the requested power adjustment is controlled by remote control or local control based on the DR signal. If it is determined in S22 that the power adjustment is controlled by remote control, GCU100 executes the power adjustment based on remote control in S23. Figure 15 This is a flowchart showing the details of S23 (remote control-based power adjustment).

[0133] and Figure 1 and Figure 2 Refer to together Figure 15 In step S31, GCU100 determines whether it has received an instruction from server 200. If GCU100 has not received the instruction (no in S31), the process proceeds to S33. In S33, GCU100 determines whether the remote control termination condition has been met. If the remote control termination condition has not been met (no in S33), the process returns to S31. For example, if the adjusted termination time arrives, the remote control termination condition is met. Additionally, the remote control termination condition is also met when a termination notification is received from server 200. However, this is not a limitation; the remote control termination condition can be arbitrarily set.

[0134] If GCU100 receives the above instruction (yes in S31), GCU100 uses the target battery in S32. Figure 14 In S104, the input / output control according to the above instructions is executed. When the battery B (other than the target battery) is disconnected from the circuit, the GCU100 causes the target battery to perform the required input / output. This performs the required power adjustment of the power system PG. After the input / output control according to the above instructions is executed in S32, the process proceeds to S33. During the period when the remote control termination condition is not met (no in S33), remote control based on the instructions from the server 200 (S31-S32) continues. Furthermore, if the remote control termination condition is met (yes in S33), then... Figure 15 The series of processes shown has ended, and processing has begun. Figure 13 S25.

[0135] If the control mode for power adjustment is determined to be local control in S22, GCU100 performs power adjustment based on local control in S24. Figure 16 This is a flowchart showing the details of S24 (power adjustment based on local control).

[0136] and Figure 1 and Figure 2 Refer to together Figure 16 The GCU100 remains in standby mode in S41 until the start time (adjustment start time) of local control arrives. If the start time of local control arrives (which is true in S41), processing proceeds to S42. In S42, the GCU100 uses the target battery ( Figure 14The GCU100 performs power regulation (more specifically, frequency control) of the power system PG using S104. The GCU100 enables the target battery to function as a primary regulator through local control. Specifically, the GCU100 performs input / output control of the target battery to stabilize the frequency of the power system PG while verifying the detection values ​​of the power sensors C1a, C1b, and C1c. When the battery B (other than the target battery) is disconnected from the circuit, the GCU100 enables the target battery to perform input / output operations to suppress frequency fluctuations in the power system PG. Thus, the required power regulation of the power system PG is performed.

[0137] After the power adjustment based on local control is performed in S42, the process proceeds to S43. In S43, GCU100 determines whether the termination condition of the power adjustment has been met. The termination condition of the power adjustment is met when the adjustment end time arrives. The termination condition of the power adjustment can also be met when a termination notification is received from server 200. During the period when the termination condition of the power adjustment is not met (no in S43), the power adjustment based on local control (S42) continues. And, if the termination condition of the power adjustment is met (yes in S43), then... Figure 16 The series of processes shown has ended, and processing has begun. Figure 13 S25.

[0138] Figure 17 This shows that power adjustment is being performed via scanning control. Figure 15 S32 or Figure 16 A diagram illustrating the state of each battery during S42. (Refer to...) Figure 17 In this example, batteries B-2 to B-5 and B-7 to B-9 each correspond to the target battery, while batteries B-1 and B-6 each correspond to batteries other than the target battery. Figure 17 As shown, during the execution of power adjustment based on scan control, batteries B-1 and B-6 are each maintained in the pass state.

[0139] Again with Figure 1 and Figure 2 Refer to together Figure 13 In S25, GCU100 releases the battery disconnection. This allows the battery that was disconnected from the circuit in S105 to be reconnected to the circuit. GCU100 then reconnects the battery B that was disconnected from the circuit as needed. For example, a battery (diagnostic target) that was excluded from the candidate battery list in S103 is reconnected to the circuit through the process in S25. Thus, in Figure 10 or Figure 11 If the condition is confirmed as yes in S14, the degradation diagnosis will restart. After the processing in S25 is executed, Figure 13 The series of processes shown has ended.

[0140] As described above, the power supply system 1 of this embodiment is configured to output AC power to the power supply object (electrical wire PGL). The power supply system 1 includes a first power supply circuit 2, a second power supply circuit 3, and a GCU 100 (control device). The first power supply circuit 2 includes a DC battery string (battery strings St1, St2, St3) for DC power and an converter (converter 11, 21, 31) for converting the DC power output from the DC battery string into AC power, configured to output first AC power using the DC battery string and the converter. The second power supply circuit 3 includes an AC battery string (battery strings St4 to St9) for AC power, configured to output second AC power using the AC battery string. The GCU 100 is configured to control the first power supply circuit 2 and the second power supply circuit 3. Each of the AC battery string and the DC battery string includes multiple battery circuit modules M connected in series. Each of the multiple battery circuit modules M includes a battery B, output terminals OT1 and OT2 for outputting the voltage of battery B, a first switch (SW51) connected to the output terminals OT1 and OT2 and in parallel with battery B, and a second switch (SW52) connected in series with battery B. The configuration is such that when the first switch is in the off state and the second switch is in the on state, the voltage of battery B is applied between the output terminals OT1 and OT2 (see reference). Figure 2 Furthermore, the GCU100 is configured to select one or more target cells from among the multiple cells contained in the AC battery string and the DC battery string to perform the required energy management. Figure 14 In S104, with the battery other than the target battery disconnected from the circuit, the target battery is used to perform the aforementioned required energy management. Figure 15 S32 or Figure 16 (S42).

[0141] Based on the above structure, it is possible to maintain the state of batteries that do not perform energy management (batteries other than the target battery in the battery string) and use the target battery to perform energy management appropriately.

[0142] In the above embodiment, the power density of the batteries included in the DC battery string is higher than that of the batteries included in the AC battery string. Furthermore, the energy density of the batteries included in the AC battery string is higher than that of the batteries included in the DC battery string. In the power system 1 of this embodiment, by using high-capacity batteries at low power supply or charging rates, long-term power supply or charging can be easily handled. Additionally, by using both high-output and high-capacity batteries at high power supply or charging rates, long-term power supply or charging can be appropriately and appropriately performed. By combining high-capacity and high-output batteries, fewer batteries are required compared to ensuring the same power supply or charging performance using only high-capacity batteries, thus reducing battery costs.

[0143] The energy management method of this implementation includes the following steps: determining whether the power fluctuation required for energy management is large ( Figure 14 (S101 and S102); when the power fluctuations that are deemed to be required for energy management are not significant (in Figure 14 If S101 is yes or S102 is no), set all batteries in the battery string as candidates for the target battery (skip). Figure 14 S103), in cases where the power fluctuation is judged to be large for energy management (in Figure 14 If S101 is negative and S102 is positive, the batteries in the degradation diagnosis will be removed from the multiple batteries contained in the battery string, and the remaining batteries will be set as candidates for the target battery. Figure 14 S103); Select one or more target batteries from the candidate target batteries ( Figure 14 S104); controls the first switch (SW51) and the second switch (SW52) in a manner that disconnects the battery other than the target battery from the circuit among the multiple batteries contained in the battery string. Figure 14 S105); and in the state where the battery other than the target battery is disconnected from the circuit, the target battery is used to perform the required energy management ( Figure 15 S32 or Figure 16 (S42).

[0144] In the above energy management method, when the required power fluctuation is small (suitable for degradation diagnosis), energy management is performed in parallel with degradation diagnosis. Conversely, when the required power fluctuation is large (unsuitable for degradation diagnosis), the battery in the degradation diagnosis is disconnected from the circuit, and the degradation diagnosis is interrupted. At this time, the battery's state in the degradation diagnosis is maintained. Therefore, after energy management ends, the interrupted degradation diagnosis can be restarted from the middle. This prevents the degradation diagnosis from being redone.

[0145] In the above implementation, the GCU100 determines whether the power fluctuation of the requested energy management is suitable for degradation diagnosis based on the response time and duration of the requested energy management (see reference). Figure 14 However, this is not the only factor; it is also possible to determine whether a power variation in the required energy management is suitable for degradation diagnosis based solely on either the response time or the duration of the required energy management. For example, it is also possible to... Figure 14S101 or S102 is omitted in the illustrated process. Additionally, the GCU100 can also determine whether the power variation of the required energy management is suitable for degradation diagnosis based on the required energy management command interval. There is a tendency for the power variation of energy management to be more easily adapted to degradation diagnosis the longer the command interval of energy management. The GCU100 can determine that the power variation of the required energy management is suitable for degradation diagnosis if the required energy management command interval is a third reference value (e.g., 10 minutes) or more.

[0146] Energy management (power regulation) is not limited to the following types. Figure 12 The types shown are as follows. For example, it could also be that energy management requirements for users in electricity markets structured differently for each country are imposed on power system 1. Examples of electricity markets include capacity markets, previous day markets (spot markets), current day markets, supply and demand adjustment markets, and real-time markets.

[0147] In the above embodiments, energy management may execute any one of the following: first output, second output, dual output, first input, second input, or dual input. However, it is not limited to this; the power system 1 may also be configured to execute any one of the following based on user requests: first output, second output, dual output, first input, second input, or dual input. The power system 1 may also supply power to the building 300 during a power outage of the power system PG.

[0148] Power generation equipment (e.g., naturally variable power sources such as solar or wind power generation equipment) may also be installed on building 300. Power system 1 may also be configured to store surplus electricity generated by the power generation equipment in a designated battery string. Alternatively, power system 1 may be configured to output power from the designated battery string to building 300 according to requests from building 300.

[0149] It should be considered that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the invention is defined not by the description of the above embodiments but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A power supply system, characterized in that, have: The first power supply circuit includes a DC battery string for DC power and a converter that converts the DC power output from the DC battery string into AC power, and outputs a first AC power using the DC battery string and the converter. The second power supply circuit has an AC battery string for AC power, and uses the AC battery string to output a second AC power. and The control device is configured to control the first power supply circuit and the second power supply circuit. Each of the AC battery string and the DC battery string comprises multiple battery circuit modules connected in series, and each of the multiple battery circuit modules comprises: Battery; The output terminal outputs the voltage of the battery. A first switch is connected to the output terminal and in parallel with the battery; and The second switch is connected in series with the battery. Each of the plurality of battery circuit modules is configured such that, when the first switch is in the off state and the second switch is in the on state, the voltage of the battery is applied to the output terminal. The control device is configured to select one or more target batteries from the plurality of batteries included in the AC battery string and the DC battery string to perform the required energy management, and to use the target battery to perform the required energy management while the batteries other than the target battery are disconnected from the circuit.

2. The power supply system according to claim 1, characterized in that, The control device is configured to perform degradation diagnosis on each of the one or more batteries included in the AC battery string and the one or more batteries included in the DC battery string, using data successively acquired during at least one of the charging and discharging processes of that battery. The control device is configured to determine whether the required power fluctuations for energy management are suitable for the degradation diagnosis. The control device is configured to, when it is determined that the power fluctuation of the required energy management is not suitable for the degradation diagnosis, exclude one or more of the batteries in the AC battery string and the DC battery string that are included in the degradation diagnosis from the selected candidates of the target battery.

3. The power supply system according to claim 2, characterized in that, The control device is configured to determine that, when the duration of the required energy management is greater than or equal to a first reference value, the power variation of the required energy management is suitable for the degradation diagnosis.

4. The power supply system according to claim 2 or 3, characterized in that, The control device is configured to determine that, if the response time of the requested energy management is below a second reference value, the power variation of the requested energy management is not suitable for the degradation diagnosis.

5. The power supply system according to any one of claims 1 to 4, characterized in that, The power density of the batteries in the DC battery string is higher than that of the batteries in the AC battery string. The energy density of the batteries in the AC battery string is higher than that of the batteries in the DC battery string.

6. The power supply system according to any one of claims 1 to 5, characterized in that, The first power supply circuit and the second power supply circuit are each electrically connected to an external power source that will supply power to the building and to the electrical wires connecting the building. The required energy management is the power regulation of the external power source.

7. The power supply system according to claim 6, characterized in that, It also includes an insulation filter configured between the first power circuit and the wire. The converter is a reused product that has been used for other purposes.

8. The power supply system according to any one of claims 1 to 7, characterized in that, The first power supply circuit includes a first driving circuit and a first control circuit. The first driving circuit drives the first switch and the second switch included in the DC battery string. The first control circuit sends signals to the first driving circuit to drive the first switch and the second switch respectively according to the instructions from the control device. The second power supply circuit includes a second driving circuit and a second control circuit. The second driving circuit drives the first switch and the second switch included in the AC battery string. The second control circuit sends signals to the second driving circuit to drive the first switch and the second switch respectively according to the instructions from the control device.

9. The power supply system according to claim 8, characterized in that, The converter is a three-phase converter. The control device is configured to send commands for controlling the DC battery string to the first control circuit and control the converter by outputting three-phase AC power from the first power supply circuit. The AC battery string includes a battery string for the U phase, a battery string for the V phase, and a battery string for the W phase that are connected by a Y connection. The control device is configured to send instructions for controlling the U-phase battery string, the V-phase battery string, and the W-phase battery string to the second control circuit in a manner that outputs three-phase AC power from the second power supply circuit.

10. A power supply system, characterized in that, have: Battery string; and Control device, controls the battery string, The battery string comprises multiple battery circuit modules connected in series. Each of the plurality of battery circuit modules includes: Battery; The output terminal outputs the voltage of the battery. A first switch is connected to the output terminal and in parallel with the battery; and The second switch is connected in series with the battery. Each of the plurality of battery circuit modules is configured such that, when the first switch is in the off state and the second switch is in the on state, the voltage of the battery is applied to the output terminal. The control device is configured to: select one or more target batteries from the plurality of batteries included in the battery string that match the required energy management; and, with the batteries other than the target battery disconnected from the circuit, use the target battery to perform the required energy management. The control device is configured to perform degradation diagnosis on each of the plurality of batteries included in the battery string using data successively acquired during at least one of the charging and discharging processes of that battery. The control device is configured to determine whether the required power fluctuations for energy management are suitable for the degradation diagnosis. The control device is configured to, when it is determined that the power fluctuation of the required energy management is not suitable for the degradation diagnosis, exclude one or more of the batteries in the battery string that are in the degradation diagnosis from the candidates for the target battery.

11. An energy management method that uses battery strings for energy management. The battery string comprises multiple battery circuit modules connected in series. Each of the plurality of battery circuit modules includes: Battery; The output terminal outputs the voltage of the battery. A first switch is connected to the output terminal and in parallel with the battery; The second switch is connected in series with the battery. Each of the plurality of battery circuit modules is configured such that, when the first switch is in the off state and the second switch is in the on state, the voltage of the battery is applied to the output terminal. This energy management method is characterized by including the following steps: Determine whether the required energy management involves significant power fluctuations; If it is determined that the power fluctuation of the required energy management is not significant, multiple batteries contained in the battery string are set as candidates for the target battery. If it is determined that the power fluctuation of the required energy management is significant, more than one battery in the degradation diagnosis is removed from the multiple batteries contained in the battery string, and the remaining battery is set as a candidate for the target battery. Select one or more of the candidate target batteries from the candidate target batteries; The first switch and the second switch are controlled in such a manner that the batteries other than the target battery among the plurality of batteries included in the battery string are disconnected from the circuit; and The required energy management is performed using the target battery while the battery other than the target battery is disconnected from the circuit.

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