JP2019193475A - Power storage device, control unit for power storage device, and control method for power storage device - Google Patents

Abstract

To provide a power storage device that improves availability of a technology to cause power storage devices to charge and discharge a power, a control unit for a power storage device, and a control method for a power storage device.SOLUTION: A power storage device comprises: a terminal unit connected in parallel to another power storage device via an electric wire; a power storage unit; a switching unit provided between the terminal unit and power storage unit; a measuring unit measuring a first voltage value according to the power storage unit; a communication unit receiving a signal indicating a second voltage value according to the terminal unit; and a control unit controlling the switching unit on the basis of the first voltage value and second voltage value.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a power storage device, a power storage device control device, and a power storage device control method.

  2. Description of the Related Art Conventionally, a technique is known in which a plurality of power storage devices having a characteristic difference are connected in parallel and charged / discharged when a characteristic difference occurs in a plurality of power storage devices constituting the power storage system due to deterioration over time. For example, in Patent Literature 1, when a voltage value of a power storage device that is not charged / discharged among a plurality of power storage devices constituting a power storage system matches a voltage value of a power storage device that has already been discharged, the power storage device A power storage system that starts charging and discharging is disclosed.

Japanese Patent No. 5618393

  An object of the present disclosure made in view of such circumstances is to provide a power storage system, a power storage device, a power storage device control device, and a power storage device control method that improve the usefulness of a technique for charging and discharging power to and from the power storage device. is there.

  A power storage device according to an embodiment of the present disclosure includes a terminal unit connected in parallel to another power storage device via an electric wire, a power storage unit, and a switching unit provided between the terminal unit and the power storage unit. A measurement unit that measures a first voltage value applied to the power storage unit, a communication unit that receives a signal indicating a second voltage value applied to the terminal unit, the first voltage value and the second voltage And a control unit that controls the switching unit based on the value.

  A control device according to an embodiment of the present disclosure includes a terminal unit connected in parallel with another power storage device via an electric wire, a power storage unit, and a switching unit provided between the terminal unit and the power storage unit. The control device is capable of controlling a power storage device including a measurement unit and a communication unit. The control device causes the power storage device to measure a first voltage value applied to the power storage unit by the measurement unit. The control device causes the power storage device to receive a signal indicating a second voltage value applied to the terminal unit through the communication unit. The control device causes the power storage device to control the switching unit based on the first voltage value and the second voltage value.

  A control method according to an embodiment of the present disclosure includes a terminal unit connected in parallel to another power storage device via an electric wire, a power storage unit, and a switching unit provided between the terminal unit and the power storage unit. A method for controlling a power storage device including a measurement unit and a communication unit. The control method includes a step of measuring a first voltage value applied to the power storage unit by the measurement unit. The control method includes a step of receiving, by the communication unit, a signal indicating a second voltage value applied to the terminal unit. The control method includes a step of controlling the switching unit based on the first voltage value and the second voltage value.

  According to the power storage system, the power storage device, the power storage device control device, and the power storage device control method according to the embodiment of the present disclosure, the utility of the technology for charging and discharging power to the power storage device is improved.

1 is a schematic configuration diagram of a power storage system according to an embodiment of the present disclosure. It is a 1st structural example of the switching part with which the electrical storage apparatus described in FIG. 1 is provided. It is a 2nd structural example of the switching part with which the electrical storage apparatus described in FIG. 1 is provided. It is a 3rd structural example of the switching part with which the electrical storage apparatus described in FIG. 1 is provided. It is a 4th structural example of the switching part with which the electrical storage apparatus described in FIG. 1 is provided. It is a sequence diagram of an example of operation | movement of the electrical storage system described in FIG. 3 is a graph illustrating an operation example of a power storage system including the power storage device illustrated in FIG. 2. FIG. 3 is a flowchart of an example of a discharge process performed by the power storage device illustrated in FIG. 2. 3 is a graph illustrating an operation example of a power storage system including the power storage device illustrated in FIG. 2. FIG. 3 is a flowchart of an example of a charging process executed by the power storage device illustrated in FIG. 2. 4 is a graph illustrating an operation example of a power storage system including the power storage device illustrated in FIG. 3. It is a flowchart of an example of the discharge process which the electrical storage apparatus of FIG. 3 performs. 5 is a graph illustrating an operation example of a power storage system including the power storage device illustrated in FIG. 4. FIG. 5 is a flowchart of an example of a charging process performed by the power storage device illustrated in FIG. 4. 6 is a graph illustrating an operation example of a power storage system including the power storage device illustrated in FIG. 5. It is a flowchart of an example of the discharge process which the electrical storage apparatus of FIG. 5 performs. 6 is a graph illustrating an operation example of a power storage system including the power storage device illustrated in FIG. 5. It is a flowchart of an example of the charging process which the electrical storage apparatus of FIG. 5 performs. 6 is a graph illustrating an operation example of a power storage system according to another embodiment of the present disclosure. 6 is a graph illustrating an operation example of a power storage system according to another embodiment of the present disclosure.

(Configuration of power storage system)
FIG. 1 is a schematic configuration diagram illustrating an example of a power storage system 1 according to an embodiment of the present disclosure. The power storage system 1 may include devices such as the power conditioner 10 and the power storage devices 20A, 20B, and 20C. In FIG. 1, the power storage devices 20 </ b> A, 20 </ b> B, and 20 </ b> C are connected in parallel by an electric wire 40 and are connected to the power system 60 via the power conditioner 10. In FIG. 1, the electric wire 40 is indicated by a solid line. The power storage system 1 is connected to the power system 60 and supplies power to a load 70 and the like connected to the power system 60. The load 70 may include any electric device that consumes electric power, such as an illumination, an air conditioner, or an information processing device. In addition, the power storage system 1 stores the power supplied from the power grid 60 in the power storage devices 20A, 20B, and 20C. Hereinafter, when the power storage devices 20A, 20B, and 20C are not particularly distinguished, they are simply referred to as a power storage device 20 in general. In the power storage system 1, devices included in the power storage system 1 such as the power conditioner 10 and the power storage device 20 are communicably connected to each other via a communication line 50. In FIG. 1, the communication line 50 is indicated by a dotted line. The communication line 50 can be configured in a bus type, for example. In FIG. 1, a power storage system 1 including one power conditioner 10 and three power storage devices 20 is illustrated as an example, but the configuration and number of devices included in the power storage system 1 are arbitrarily determined. May be. For example, each of the power conditioner 10 and the power storage device 20 may be individually added or removed according to requirements such as a charging capacity required for the power storage system 1. The communication line 50 may be wired or wireless.

  The power conditioner 10 is also referred to as a PCS (Power Conditioning System). The power conditioner 10 controls charging / discharging of the electric power of the power storage device 20, for example. In that case, the power conditioner 10 is controlled so that the voltage value of the electric power charged / discharged by the power storage device 20 is constant, or the current value of the electric power charged / discharged is constant. Constant current control may be performed. The power conditioner 10 converts the DC power from the power storage device 20 into AC power and outputs the AC power to the power system 60 or the load 70 or the like, or converts the AC power from the power system 60 into DC power to the power storage device 20. Output.

  The power storage device 20 supplies power to a load 70 or the like connected to the power system 60. The power storage device 20 may supply power that can be sold to the power system 60. In addition, the power storage device 20 stores the power supplied from the power system 60. The power storage device 20 may be, for example, a lithium ion battery, a lead storage battery, a sodium sulfur battery, a nickel hydrogen storage battery, or another storage battery. Based on the control signal received from the power conditioner 10, the power storage device 20 may perform operations such as power charging and discharging, or transmission of a signal including information regarding the power storage device 20 itself. Hereinafter, the power storage device itself is also referred to as a self device.

  In the power storage system 1 according to an embodiment of the present disclosure, for example, the power conditioner 10 specifies a maximum value or a minimum value among the voltage values of the power storage unit of the power storage device 20 and outputs a control signal for charging or discharging. It transmits to each of the power storage devices 20. The power storage device 20 controls the switching unit based on the comparison between the voltage value specified by the control signal and the voltage value of the own device, and performs charging or discharging by increasing or decreasing the power, or charging / discharging operation. Stop. As a result, the power storage devices 20 having different voltage values included in the power storage system 1 can be charged and discharged. Details will be described below.

(Configuration of power storage device)
Below, schematic structure of the electrical storage apparatus 20 which is an example of the electrical storage apparatus which concerns on one Embodiment of this indication is shown. In FIG. 1, a power storage device 20 includes a control unit 21, a power storage unit 22, a measurement unit 23, a terminal unit 24, a switching unit 25, a switch 26, a communication unit 27, a storage unit 28, a notification unit 29, an input unit 30, and an electric wire. Equipped with 31 functional units.

  As will be described in detail later, the control unit 21 is one or more processors that provide control and processing capability for realizing each function of the power storage device 20. The control unit 21 may be configured by a processor such as a CPU (Central Processing Unit) that executes a program that defines a control procedure, or a dedicated processor specialized for processing of each function.

  The control unit 21 is connected to each functional unit of the power storage device 20 described above by wire or wirelessly, and controls and manages all or part of the power storage device 20 including these functional units. The control unit 21 obtains a program stored in the storage unit 28 and executes this program, thereby realizing various functions related to each functional unit of the power storage device 20. Control characteristic of the present embodiment performed by the control unit 21 will be further described later.

  The power storage unit 22 charges and discharges power based on the control of the control unit 21. The power storage unit 22 is arranged to be energized with the outside of the power storage device 20 via a terminal unit 24 described later. The charging and discharging of electric power in the power storage unit 22 may be controlled and managed by the control unit 21 in units of cells constituting the power storage unit 22. The power storage unit 22 may include a plurality of cells. The cells may be controlled and managed by the control unit 21 in units of modules in which a plurality of cells are connected.

  The voltage value applied to the power storage unit 22 of each power storage device 20 included in the power storage system 1 may vary depending on conditions such as the degree of deterioration of the power storage devices 20 or the charging rate. For example, even if the power storage devices 20 have the same specifications and performance, the degree of deterioration of each power storage device 20 varies depending on the number of times of use, frequency of use, installation environment, or the like. Since the charge capacity and the discharge capacity of the power storage device 20 differ depending on the degree of deterioration of the power storage device 20, for example, the voltage value applied to the power storage unit 22 in a fully charged or empty state can be different. Hereinafter, the degree of deterioration is also referred to as SOH (State of Health). The SOH can be expressed as a ratio (%) of the current full charge capacity (FCC) to the design capacity (DC). Further, even if the charge capacities of the respective power storage devices are the same, the voltage values applied to the respective power storage units 22 may be different when the charge amounts are different. Hereinafter, the charging rate is also referred to as SOC (States Of Charge). The SOC can be expressed as a ratio (%) of the current charge amount to the full charge capacity.

  The measurement unit 23 measures a voltage value applied to the power storage unit 22. The measurement unit 23 may be a voltmeter. In the present specification, the voltage value applied to the power storage unit 22 measured by the measurement unit 23 is also referred to as a first voltage value. The measurement unit 23 transmits the measured voltage value to the control unit 21. The measurement unit 23 may be installed at an arbitrary position. For example, the measurement unit 23 is provided as a separate body from the power storage unit 22, but is not limited thereto. The measurement unit 23 may be provided inside the power storage unit 22. Moreover, the number of the measurement parts 23 may be arbitrary. For example, a plurality of measurement units 23 may be provided in units of modules or cells, and a voltage value applied to the power storage unit 22 may be calculated from values measured by the measurement units 23.

  Terminal portion 24 is connected in parallel to another power storage device 20 via an electric wire. Terminal unit 24 includes a terminal to which electric wire 40 or the like is connected from the outside of power storage device 20. In the present embodiment, it is assumed that the power storage device 20 is connected to other devices in parallel connection. Therefore, the terminal portion 24 may include a positive terminal 24A and a negative terminal 24B. In FIG. 1, the positive terminal 24A is connected to the positive terminal of the power storage unit 22 via the electric wire 31A, and the negative terminal 24B is connected to the negative electrode terminal of the power storage unit 22 via the electric wire 31B. The number of terminals included in the terminal unit 24 may be an arbitrary number. For example, when the power storage unit 22 of the power storage device 20 includes a plurality of cells, the terminal unit 24 may include a plurality of terminals corresponding to the number of cells. The other device may be a device such as the power conditioner 10 or the power storage device 20, for example. The devices connected by the electric wires 40 are not limited to the power conditioner 10 and the power storage device 20. For example, any power supply device including a solar cell, a wind power generation device, a hydroelectric power generation device, a fuel cell, or an information processing device may be used. Any device may be included.

  In FIG. 1, the positive terminal 24A and the negative terminal 24B of the terminal portion 24 of the power storage device 20A are connected to the power conditioner 10, and the positive and negative terminals of the other power storage devices 20B and 20C, respectively, via the wires 40A and 40B. . Thereby, in power storage system 1, power storage devices 20A, 20B, and 20C are connected in parallel. In the present embodiment, the power storage device 20 is described as including one terminal unit 24, but this is not a limitation. The number of the terminal portions 24 included in the power storage device 20 may be an arbitrary number depending on the connection method with other devices in the power storage system 1.

  The switching unit 25 is provided between the terminal unit 24 and the power storage unit 22. Based on the control of the control unit 21, the switching unit 25 can switch the power input / output between the terminal unit 24 and the power storage unit 22. Further, the switching unit 25 can transform the electric power input / output between the terminal unit 24 and the power storage unit 22 based on the control of the control unit 21. The control of the switching unit 25 may be performed based on a predetermined voltage value. For example, the predetermined voltage value includes a voltage value applied to the power storage unit 22. Hereinafter, the voltage value applied to the power storage unit 22 is also referred to as a first voltage value. Further, the predetermined voltage value may be a voltage value of input / output power specified when charging / discharging the power storage device 20 included in the power storage system 1. Hereinafter, the voltage value of the input / output power specified when charging / discharging is also referred to as a second voltage value. The second voltage value may be a voltage value applied to the terminal unit 24 of the power storage device 20. For example, during charging / discharging of the power storage device 20 included in the power storage system 1, the power conditioner 10 may be controlled so that the potential difference between the electric wires 40 </ b> A and 40 </ b> B becomes the second voltage value. The control unit 21 may control the switching unit 25 based on the first voltage value and the second voltage value. The configuration of the switching unit 25 includes an operation for switching between input and output of power, an operation for boosting or stepping down the power charged in the power storage unit 22, or an operation for boosting or stepping down the power discharged from the power storage unit 22. Depending on, any configuration may be possible. A configuration example of the switching unit 25 is shown below.

(Configuration example 1 of switching unit)
As an example of the configuration of the switching unit, a switching unit 25A is shown in FIG. The switching unit 25A may include a switching element 32. In FIG. 2, the switching element 32 is provided on the electric wire 31 </ b> A that connects the positive terminal 24 </ b> A of the terminal unit 24 and the positive terminal of the power storage unit 22. The switching element 32 may be any switching element such as a transistor or a MOSFET, for example. The switching unit 25 </ b> A having such a configuration switches whether or not power can be input and output between the terminal unit 24 and the power storage unit 22 by switching the switching element 32 by the control unit 21. Moreover, the control part 21 can control a voltage or an electric current in 25 A of switching parts by switching the switching element 32 and controlling it to have a predetermined resistance value. The control unit 21 may control the switching element 32 by PWM (Pulse Width Modulation).

(Configuration example 2 of switching unit)
As another configuration example of the switching unit, a switching unit 25B is shown in FIG. The switching unit 25B may be a DC / DC converter including a switching element 32, a coil 33, and a diode 34. In FIG. 3, in addition to the switching element 32 described in the configuration example 1, a coil 33 is provided on the terminal part 24 side of the switching element 32 of the electric wire 31A. A diode 34 is provided to connect the electric wire 31B between the switching element 32 of the electric wire 31A and the coil 33. When the switching unit 25B having such a configuration discharges from the power storage device 20, that is, when power is output from the power storage unit 22 to the terminal unit 24, the switching unit 25B is repeatedly input to the switching unit 25B. The power is stepped down and output. When the power is not stepped down in the switching unit 25B, the control unit 21 may control the switching element 32 to be kept in a closed state.

(Configuration Example 3 of Switching Unit)
As another configuration example of the switching unit, a switching unit 25C is shown in FIG. The switching unit 25C may be a DC / DC converter including two switching elements 32A and 32B and a coil 33. Referring to FIG. 4, a switching element 32 </ b> B is provided instead of the diode 34 in the configuration described in the configuration example 2 above. The switching unit 25C having such a configuration steps down and outputs the power input to the switching unit 25C by repeatedly switching the switching elements 32A and 32B when discharging from the power storage device 20. In addition, the switching unit 25C is input to the switching unit 25C by repeatedly switching the switching elements 32A and 32B when charging the power storage device 20, that is, when outputting power from the terminal unit 24 to the power storage unit 22. Boosts and outputs power. When the switching unit 25C does not step down or boost the power, the control unit 21 may control the switching element 32A to be in a closed state and the switching element 32B to be in an open state.

(Configuration Example 4 of Switching Unit)
As another configuration example of the switching unit, a switching unit 25D is shown in FIG. The switching unit 25D may be a DC / DC converter including two switching elements 32A and 32B and a coil 33. Referring to FIG. 5, the coil 33 and the switching element 32 </ b> A are replaced with the configuration described in the configuration example 3. The switching unit 25D having such a configuration boosts and outputs the power input to the switching unit 25D by repeatedly switching the switching elements 32A and 32B when discharging from the power storage device 20. Further, when charging the power storage device 20, the switching unit 25 </ b> D steps down and outputs the power input to the switching unit 25 </ b> D by repeatedly switching the switching elements 32 </ b> A and 32 </ b> B. When the switching unit 25D does not step down or boost the power, the control unit 21 may control the switching element 32A to be in a closed state and the switching element 32B to be in an open state.

  The switch 26 is provided so that the terminal part 24 and the electrical storage part 22 may be connected to be energized. Thereby, when the switch 26 is closed, the power storage unit 22 of the power storage device 20 and another device connected via the terminal unit 24 are connected to be energized. On the other hand, when the switch 26 is opened, energization between the power storage unit 22 of the power storage device 20 and other devices connected via the terminal unit 24 is interrupted. The number of the switches 26 may be an arbitrary number.

  The communication unit 27 communicates with other devices based on the control of the control unit 21. The communication unit 27 may include, for example, a CAN (Controller Area Network) communication module, a wired LAN communication module, or a wireless LAN (Local Area Network) communication module. In FIG. 1, the communication unit 27 of the power storage device 20 </ b> A is connected to a common communication line 50 together with the power conditioner 10 and the power storage devices 20 </ b> B and 20 </ b> C included in the power storage system 1. Thereby, for example, the power storage device 20A can receive a control signal for controlling the power storage device from another device included in the power storage system 1 and operate based on the received control signal. The control signal includes a command for starting an operation such as charging / discharging of the power storage device or a command for stopping the operation, but is not limited thereto. In addition, the power storage device 20 can transmit and receive a signal indicating a second voltage value, details of which will be described later, to and from other devices included in the power storage system 1. In order to transmit and receive signals, the power storage device 20 and other devices connected to the communication line 50 are given information for uniquely identifying the device when performing communication such as an identifier (ID). May be. In such a case, the signal may include information such as an ID for specifying a target device, a signal transmission source device, or a signal transmission destination device.

  The storage unit 28 includes, for example, a semiconductor memory, a magnetic memory, an optical memory, or the like. The storage unit 28 may function as, for example, a main storage device or an auxiliary storage device. The storage unit 28 may be a cache memory of a processor included in the control unit 21. The storage unit 28 may be a volatile storage device or a non-volatile storage device. The storage unit 28 stores information and programs used for control and processing for realizing each function of the power storage device 20. For example, the storage unit 28 may store information for uniquely specifying other devices included in the power storage system 1. For example, the information for uniquely specifying another device may include the above-described ID or the like. Further, the storage unit 28 may store conditions used for controlling the switching unit described later. At least a part of the information and programs stored in the storage unit 28 may be shared or synchronized with other devices.

  The notification unit 29 notifies information by sound, vibration, lighting of a light, an image, and the like. For example, the notification unit 29 includes at least one of a speaker, a vibrator, a light, a display device, and the like. The display device can be, for example, a liquid crystal display or an organic EL display. The notification unit 29 is based on the control of the control unit 21 and includes at least an ID of the power storage device 20, information on the remaining amount of power charged in the power storage device 20, an operation state including charging / discharging of the power storage device 20, etc. One may be notified.

  The input unit 30 receives an input operation from the user. The input unit 30 may include, for example, an input device such as a touch panel, a keyboard, a mouse, a camera, or a microphone that is provided integrally with the display device of the notification unit 29. When detecting the user operation, the input unit 30 transmits the user operation to the control unit 21 as electronic information. At least one of the notification unit 29 and the input unit 30 may be provided in, for example, a remote control, a tablet terminal, a personal computer, or a control device that is physically separated from the power storage device 20.

  Hereinafter, control of each function of the power storage device 20 by the control unit 21 will be described. The control unit 21 measures the first voltage value applied to the power storage unit 22 by the measurement unit 23. The control unit 21 transmits a voltage value measurement request to the measurement unit 23, and receives the first voltage value applied to the power storage unit 22 measured by the measurement unit 23 based on the voltage value measurement request from the measurement unit 23. Also good. Alternatively, the control unit 21 may calculate the first voltage value applied to the power storage unit 22 based on the value measured by the measurement unit 23.

  The control unit 21 receives a signal indicating the second voltage value through the communication unit 27. The control unit 21 may receive the signal by any method. For example, the control unit 21 may receive a signal indicating the second voltage value transmitted by another device at a predetermined time interval or the like. Or the control part 21 transmits the transmission request | requirement of the signal which shows a 2nd voltage value to another apparatus by the communication part 27, and the signal which shows the 2nd voltage value which the other apparatus transmitted based on the said transmission request May be received.

  The signal indicating the second voltage value may include the second voltage value or information used for calculating the second voltage value. For example, the signal indicating the second voltage value includes the second voltage value calculated based on the voltage value applied to the power storage units 22 of the power storage devices 20A, 20B, and 20C included in the power storage system 1 by the power conditioner 10. May be included. In such a case, the second voltage value may be a voltage at a terminal of the power conditioner 10 or the power storage device 20. The second voltage value may be measured by a voltmeter that measures the voltages at the terminal portion of the power conditioner 10 and the terminals 24A and 24B of the power storage device 20. The second voltage value can be measured by, for example, a voltmeter that measures a voltage between the electric wires 31A and 31B included in the respective power storage devices 20A, 20B, and 20C. For example, the second voltage value may be a maximum value, a minimum value, or an average value of the voltage values applied to the power storage units 22 of the power storage devices 20A, 20B, and 20C. In such a case, the control unit 21 of each power storage device 20 controls its own device so as to discharge or charge based on the second voltage value. Further, the signal indicating the second voltage value includes the voltage value applied to the power storage unit 22 of the own device measured by the other power storage device 20 as information used to calculate the second voltage value. May be. In such a case, the control unit 21 of the power storage device 20 determines the maximum value, minimum value, average value, or the like of the received voltage value applied to the power storage unit 22 of the other power storage device 20 and the first voltage value of the own device. It may be calculated as a voltage value of 2. The control unit 21 of the power storage device 20 controls the own device so as to perform discharging or charging based on the calculated second voltage value. The information used to calculate the second voltage value is not limited to the voltage value applied to the power storage unit 22 of another power storage device 20. The information used for calculating the second voltage value may be, for example, the SOC, SOH of the power storage unit 22 of the other power storage device 20 described above, or the current value measured by the other power storage device 20. Good.

  The signal indicating the second voltage value may include other information in addition to the above-described second voltage value or information used to calculate the second voltage value. For example, the signal indicating the second voltage value may include a control command for causing the power storage device to perform an operation such as charging or discharging. Thereby, the signal indicating the second voltage value can be used as, for example, a control signal for discharging by designating the second voltage value, or a control signal for charging by designating the second voltage value. The other information may further include arbitrary information such as an operation start condition and an end condition, a control start time and an end time, or a control duration. Thus, a more detailed control instruction can be transmitted to power storage device 20 using the signal indicating the second voltage value.

  The control unit 21 controls the switching unit 25 based on the first voltage value and the second voltage value. Based on the first voltage value and the second voltage value, the control unit 21 may control the switching unit 25 to switch whether power can be input and output between the terminal unit 24 and the power storage unit 22. For example, the control unit 21 may determine whether or not the potential difference between the first voltage value and the second voltage value applied to the power storage unit 22 of the own device is within a predetermined range. When it is determined that the potential difference is within a predetermined range, the control unit 21 may control the switching unit 25 so that the electric power input to the switching unit 25 is output as it is without being transformed. When it is determined that the potential difference is not within the predetermined range, the control unit 21 may control the switching unit 25 so as to cut off input / output of power between the terminal unit 24 and the power storage unit 22.

  For example, it is assumed that potential differences occur in the power storage devices 20A, 20B, and 20C included in the power storage system 1, and the voltage value of the power storage device 20A is the lowest. When the control unit 21 of the power storage device 20A receives a control signal for discharging by designating a second voltage value higher than the first voltage value of the own device, the control unit 21 blocks the input / output of power by the switching unit 25. Do not discharge. The discharge from the other power storage device 20 of the power storage system 1 proceeds, and the voltage value of the other power storage device 20 decreases. As the voltage value of the other power storage device 20 decreases, the second voltage value also decreases. After that, after the potential difference between the first voltage value and the second voltage value of the own device falls within a predetermined range, when receiving a control signal for discharging by designating the second voltage value, the control unit 21 The power is input / output by the switching unit 25, and discharging is performed. As a result, the power storage devices 20A, 20B, and 20C included in the power storage system 1 can eliminate the mutual potential difference and continue the discharge.

  Further, the control unit 21 controls the switching unit 25 based on the first voltage value and the second voltage value, and transforms the electric power input / output between the terminal unit 24 and the power storage unit 22. May be. For example, the control unit 21 may calculate a potential difference between the first voltage value and the second voltage value. When it is determined that the potential difference is not within the predetermined range, the control unit 21 may control the switching unit 25 so as to increase or decrease the power input to the switching unit 25 by the amount corresponding to the potential difference. . When it is determined that the potential difference is within a predetermined range, the control unit 21 may control the switching unit 25 so that the electric power input to the switching unit 25 is output as it is without being transformed.

  For example, it is assumed that potential differences occur in the power storage devices 20A, 20B, and 20C included in the power storage system 1, and the voltage value of the power storage device 20A is the lowest. When the control unit 21 of the power storage device 20A receives a control signal for designating and discharging a second voltage value higher than the first voltage value of the own device, the switching unit 25 causes the first voltage value and the second voltage to be discharged. The electric power is boosted by the potential difference from the voltage value of to discharge. The discharge from the other power storage device 20 of the power storage system 1 proceeds, and the voltage value of the other power storage device 20 decreases. As the voltage value of the other power storage device 20 decreases, the second voltage value also decreases. After that, after the potential difference between the first voltage value and the second voltage value of the own device falls within a predetermined range, when receiving a control signal for discharging by designating the second voltage value, the control unit 21 Then, discharging is performed without increasing the power by the switching unit 25. As a result, the power storage devices 20A, 20B, and 20C included in the power storage system 1 can eliminate the mutual potential difference and continue the discharge.

  In the present disclosure, some or all of the functions of the power storage device 20 including the control unit 21 described above may be provided by a control device that controls the power storage device 20. The control device may be included in power storage device 20 or may be provided separately from power storage device 20. When provided separately, the control device is, for example, a home energy management system (HEMS), a battery management system (Battery Management System: BMS), a remote control, a mobile phone, a smartphone, a tablet terminal, or a PC (Personal Computer). ) And the like, an information processing device that can control the power storage device 20 may be used. The control device may be the above-described power conditioner 10 or another power storage device 20.

(Operation example of power storage system)
Hereinafter, an example of control of the power storage device 20 executed by the power storage system 1 according to an embodiment of the present disclosure will be described. As shown in FIG. 1, the power storage system 1 includes a power conditioner 10 and power storage devices 20A, 20B, and 20C. The power storage devices 20A, 20B, and 20C are connected in parallel. In the power storage system 1, the power conditioner 10 operates as a control device for the power storage devices 20A, 20B, and 20C. In FIG. 6, the sequence diagram of the process of the electrical storage system 1 is shown. Specifically, the power storage devices 20A, 20B and 20C measure the first voltage value and transmit it to the power conditioner 10 (steps S101 to S102). The power conditioner 10 calculates the maximum value or the minimum value of the first voltage value received from the power storage devices 20A, 20B, and 20C and sets it as the second voltage value (step S103). The power conditioner 10 designates the second voltage value and transmits a control signal for charging or discharging to the power storage devices 20A, 20B, and 20C (step S104). The power storage devices 20A, 20B, and 20C control the switching unit 25 based on the first voltage value and the second voltage value, and perform charging or discharging (step S105). The power conditioner 10 and the power storage devices 20A, 20B, and 20C realize charging / discharging by the power storage system 1 by repeating the above-described operation. Hereinafter, details of an operation example of the power storage system 1 will be described for each case where the power storage device 20A includes the switching unit 25 of the configuration examples 1 to 4 described above.

(Operation example 1 of power storage system)
With reference to FIGS. 1, 2, and 7, an operation example during discharging of the power storage system 1 in which the power storage device 20 includes the switching unit 25 of the configuration example 1 will be described. The power conditioner 10 receives the first voltage value measured by the power storage devices 20A, 20B, and 20C (steps S101 and S102). When the power storage system 1 is discharged, the power conditioner 10 sets the maximum value of the first voltage values of the power storage devices 20A, 20B, and 20C as the second voltage value (step S103). The power conditioner 10 transmits a control signal to be discharged by designating the second voltage value to the power storage devices 20A, 20B, and 20C (step S104). For example, as shown in FIG. 7, it is assumed that the first voltage values of the power storage devices 20A, 20B, and 20C are Va, Vb, and Vc, respectively, and Va>Vb> Vc at time ts. When the power conditioner 10 starts discharging the power storage system 1 at time ts, the power conditioner 10 transmits a control signal to the power storage devices 20 </ b> A, 20 </ b> B, and 20 </ b> C to discharge by specifying the value Va as the second voltage value V <b> 2. When the power storage devices 20A, 20B, and 20C receive the discharge control signal, the power storage devices 20A, 20B, and 20C compare the first voltage values Va, Vb, and Vc applied to the respective power storage units 22 with the second voltage value V2 included in the control signal. (Step S105). When the difference between the first voltage value and the second voltage value is within a predetermined range, the power storage devices 20A, 20B, and 20C perform the discharge by controlling the switching unit 25. In addition, the power storage devices 20A, 20B, and 20C stop the discharge by controlling the switching unit 25 if the difference between the first voltage value and the second voltage value is not within a predetermined range (step S106). Since V2 = Va>Vb> Vc at time ts, only power storage device 20A starts discharging. On the other hand, power storage devices 20B and 20C do not start discharging.

  During charging / discharging of the power storage system 1, the power conditioner 10 receives the first voltage values of the power storage devices 20A, 20B, and 20C, for example, at regular time intervals, and receives the maximum voltage values of the power storage devices 1 Reset the voltage value. In FIG. 7, the transition of the second voltage value is indicated by a solid line. Each time the second voltage value is reset, the power conditioner 10 transmits a control signal for designating and discharging the reset second voltage value to the power storage devices 20A, 20B, and 20C. When discharging of power storage device 20A proceeds and the first voltage value of power storage device 20A becomes equal to Vb at time t1, second voltage value V2 set in the control signal by power conditioner 10 is equal to Va and Vb. Become. Since V2 = Va = Vb> Vc, in addition to the power storage device 20A, the power storage device 20B performs discharging. On the other hand, power storage device 20C does not discharge. Furthermore, when the discharge of the power storage devices 20A and 20B proceeds and the second voltage value V2 becomes equal to Va, Vb, and Vc at time t2, the power storage device 20C starts discharging because V2 = Va = Vb = Vc. . Thereby, the power storage devices 20A, 20B, and 20C are discharged. Thereafter, each power storage device receives a control signal for terminating the discharge, or the discharge end condition is satisfied when the first voltage value reaches the discharge end voltage value set in each power storage device. Discharge is terminated.

(Processing example 1 of power storage device)
With reference to FIG. 8, an example of processing executed by the power storage device 20 that is the power storage device according to the embodiment of the present disclosure will be described. This process is a discharge process performed by the power storage device 20 including the switching unit 25 of the configuration example 1.

  Step S201: The control unit 21 measures the first voltage value by the measurement unit 23.

  Step S202: The control unit 21 transmits a signal indicating the first voltage value.

  Step S203: The control unit 21 receives a signal indicating the second voltage value.

  Step S204: The control unit 21 determines whether or not the potential difference between the first voltage value and the second voltage value is within a predetermined range.

  Step S205: When the potential difference is within the predetermined range (step S204—Yes), the control unit 21 turns on the switching unit 25 to perform discharge.

  Step S206: When the potential difference is not within the predetermined range (step S204-No), the control unit 21 turns off the switching unit 25 and stops discharging.

  Step S207: The control unit 21 determines whether or not the discharge end condition is satisfied. When the end condition is satisfied (step S207—Yes), the control unit 21 ends this process. When the termination condition is not satisfied (step S207—No), the control unit 21 repeats the process from S201.

  With reference to FIGS. 1, 2, and 9, an operation example during charging of the power storage system 1 in which the power storage device 20 includes the switching unit 25 of the configuration example 1 will be described. First voltage values Va, Vb, and Vc when power storage devices 20A, 20B, and 20C are charged to full charge are set to maximum voltage values Vamax, Vbmax, and Vcmax. The power conditioner 10 performs the constant current control until all the power storage devices 20 to be charged reach the maximum voltage value, and performs the constant voltage control when reaching the maximum voltage value. Therefore, when the power storage system 1 is charged, the power conditioner 10 designates the maximum value of the first voltage value of the power storage devices 20A, 20B, and 20C as the second voltage value V2 and charges the control signal. Transmit to 20A, 20B and 20C.

  Constant current control is performed in the initial stage of charging. Until the first voltage value Vc of the power storage device 20C reaches Vcmax at time t1 in FIG. 9, equal voltages are applied to the first voltage values Va, Vb, and Vc of the power storage devices 20A, 20B, and 20C. Therefore, the charging proceeds with the second voltage value V2 = Va = Vb = Vc. Each of the power storage devices 20A, 20B, and 20C compares the first voltage values Va, Vb, and Vc applied to the power storage unit 22 of the own device with the second voltage value V2 included in the control signal. Each of the power storage devices 20A, 20B, and 20C is charged with the second voltage value V2 by controlling the switching unit 25 to be on because the difference between the first voltage value and the second voltage value is within a predetermined range. To implement.

  After that, when the first voltage value Vc of the power storage device 20C reaches the maximum voltage value Vcmax at time t1, the first voltage value Vc of the power storage device 20C cannot increase any further, so the first voltage value of the power storage device 20C The difference between the value Vc and the second voltage value V2 exceeds a predetermined range. Since the other power storage devices 20A and 20B continue to be charged, the power storage device 20C controls the switching unit 25 to be turned off and terminates charging of the own device. Similarly, the power storage device 20B is charged at the second voltage value V2 until time t2, and when the first voltage value Vb reaches the maximum voltage value Vbmax at time t2, charging of the other power storage device 20A is continued. Because of this, charging of the own device is terminated. As shown in FIG. 9, the first voltage values Vb and Vc of the power storage devices 20B and 20C gradually decrease due to natural discharge after the end of charging. The power storage device 20A is charged at the second voltage value V2 until the time te. When the first voltage value Va reaches the maximum voltage value Vamax at the time te, the charging of the other power storage device 20A is continued. It is determined whether or not. At time te, charging is continued because there is no other power storage device 20 being charged. Thereafter, the power conditioner 10 transmits a control signal for charging by specifying the first voltage value Va = Vamax of the power storage device 20A as the second voltage value V2. Therefore, constant voltage control by trickle charging that compensates for natural discharge is performed in power storage device 20A until charging termination conditions are satisfied.

(Processing example 2 of power storage device)
With reference to FIG. 10, an example of processing executed by the power storage device 20 that is the power storage device according to an embodiment of the present disclosure will be described. This process is a charging process performed by the power storage device 20 including the switching unit 25 of the configuration example 1.

  Step S301: The control unit 21 measures the first voltage value by the measurement unit 23.

  Step S302: The control unit 21 transmits a signal indicating the first voltage value.

  Step S303: The control unit 21 receives a signal indicating the second voltage value.

  Step S304: The control unit 21 determines whether or not the potential difference between the first voltage value and the second voltage value is within a predetermined range.

  Step S305: When the potential difference is within the predetermined range (step S304—Yes), the control unit 21 turns on the switching unit 25 to perform charging.

  Step S306: When the potential difference is not within the predetermined range (step S304—No), the control unit 21 determines whether there is another power storage device 20 that is being charged. When there is another power storage device 20 that is being charged (step S306-Yes), the control unit 21 turns on the switching unit 25 to perform charging.

  Step S307: When there is no other power storage device 20 that is being charged (step S306-No), the control unit 21 turns off the switching unit 25 to stop charging, and ends this process.

  Step S308: The control unit 21 determines whether or not the charging termination condition is satisfied. When the end condition is satisfied (step S308-Yes), the control unit 21 ends the process. When the end condition is not satisfied (step S308-No), the control unit 21 repeats this process from S301.

(Operation example 2 of power storage system)
With reference to FIG. 1, FIG. 3, and FIG. 11, the operation example at the time of discharge of the electrical storage system 1 with which the electrical storage apparatus 20 is provided with the switching part 25 of the structural example 2 is demonstrated. When the power storage system 1 is discharged, the power conditioner 10 designates the minimum value of the first voltage value of the power storage devices 20A, 20B, and 20C as the second voltage value V2, and discharges the control signal to the power storage devices 20A, 20B. And 20C. For example, as shown in FIG. 11, it is assumed that the first voltage values of the power storage devices 20A, 20B, and 20C are Va, Vb, and Vc, respectively, and Va>Vb> Vc at time ts. When the power conditioner 10 starts discharging the power storage system 1 at time ts, the power conditioner 10 transmits a control signal to the power storage devices 20 </ b> A, 20 </ b> B, and 20 </ b> C to discharge by designating the second voltage value V <b> 2 as Vc. When the power storage devices 20A, 20B, and 20C receive the discharge control signal, the first voltage values Va, Vb, and Vc applied to the respective power storage units 22 are compared with the second voltage value V2 included in the control signal. . When the difference between the first voltage value and the second voltage value is within a predetermined range, the power storage devices 20A, 20B, and 20C output the power input to the switching unit 25 as it is without being transformed. To control the discharge. On the other hand, the power storage devices 20A, 20B, and 20C control the switching unit 25 if the difference between the first voltage value and the second voltage value is not within the predetermined range, and the second voltage value from the first voltage value. Step down to discharge. Until time t1, since V2 = Vc <Vb <Va, only the power storage device 20C is discharged with the first voltage value. On the other hand, power storage devices 20A and 20B perform discharge by stepping down from first voltage values Va and Vb to second voltage value V2, respectively.

  The power conditioner 10 receives the first voltage value of each of the power storage devices 20A, 20B, and 20C at a constant time interval during the discharge of the power storage system 1, and sets the minimum voltage value to the second voltage value. Reset to V2. In FIG. 11, the transition of the second voltage value V2 is indicated by a solid line. Each time the second voltage value V2 is reset, the power conditioner 10 transmits a control signal for designating and discharging the reset second voltage value V2 to the power storage devices 20A, 20B, and 20C. When discharging of each power storage device 20 proceeds and the first voltage value of power storage device 20B becomes equal to Vc at time t1, second voltage value V2 set by power conditioner 10 becomes equal to Va and Vb. . Since V2 = Vc = Vb <Va, the power storage devices 20B and 20C are discharged at the first voltage values Vb and Vc without being transformed. On the other hand, the power storage device 20A transforms from the first voltage value Va to the second voltage value V2 to discharge. Thereafter, discharging of the power storage device 20 further proceeds, and when the second voltage value V2 becomes equal to Va, Vb, and Vc at time t2, since V2 = Va = Vb = Vc, the power storage devices 20A, 20B, and 20C Discharging is performed at the first voltage values Va, Vb, and Vc without being transformed. Thereafter, each power storage device receives a control signal for terminating the discharge, or the discharge end condition is satisfied when the first voltage value reaches the discharge end voltage value set in each power storage device. Discharge is terminated.

(Processing example 3 of power storage device)
With reference to FIG. 12, an example of processing executed by the power storage device 20 that is the power storage device according to an embodiment of the present disclosure will be described. This process is a discharge process performed by the power storage device 20 including the switching unit 25 of the configuration example 2.

  Step S401: The control unit 21 measures the first voltage value by the measurement unit 23.

  Step S402: The control unit 21 transmits a signal indicating the first voltage value.

  Step S403: The control unit 21 receives a signal indicating the second voltage value.

  Step S404: The control unit 21 determines whether or not the potential difference between the first voltage value and the second voltage value is within a predetermined range.

  Step S405: When the potential difference is within the predetermined range (step S404-Yes), the control unit 21 performs discharging without stepping down the voltage by the switching unit 25.

  Step S406: When the potential difference is not within the predetermined range (No at Step S404), the control unit 21 performs a discharge by reducing the voltage by the switching unit 25.

  Step S407: The control unit 21 determines whether or not a discharge termination condition is satisfied. When the end condition is satisfied (step S407-Yes), the control unit 21 ends this process. When the end condition is not satisfied (step S407-No), the control unit 21 repeats this process from S401.

  The operation at the time of charging of the power storage system 1 having the power storage device 20 of the configuration example 2 is the same as that of the power storage system 1 having the power storage device 20 of the configuration example 1 described above with reference to FIGS. When the power storage system 1 is charged, the power conditioner 10 designates the maximum value of the first voltage value of the power storage devices 20A, 20B and 20C as the second voltage value and charges the power storage devices 20A, 20B and 20C. Send to 20C. First voltage values Va, Vb, and Vc when power storage devices 20A, 20B, and 20C are charged to full charge are set to maximum voltage values Vamax, Vbmax, and Vcmax. The power conditioner 10 performs constant current control until all the power storage devices 20 to be charged reach their maximum voltage values, and performs constant voltage control when they reach the maximum voltage value. Each power storage device 20 is charged with the second voltage value V2 until the first voltage value reaches the maximum voltage value. When the first voltage value reaches the maximum voltage value, each power storage device 20 ends the charging of its own device if the other power storage devices 20 continue to be charged. On the other hand, when the first voltage value reaches the maximum voltage value, each power storage device 20 continues to charge its own device if charging of the other power storage devices 20 is not continued. The charging process by the power storage device 20 including the switching unit 25 of the configuration example 2 is the same as the charging process by the power storage device 20 including the switching unit 25 of the configuration example 1 described above with reference to FIG.

(Operation example 3 of power storage system)
With reference to FIG. 1, FIG. 4, the operation example at the time of discharge of the electrical storage system 1 with which the electrical storage apparatus 20 is provided with the switching part 25 of the structural example 3 is demonstrated. The operation of the power storage system 1 at the time of discharging is the same as that of the power storage system 1 having the power storage device 20 of the configuration example 2 described above with reference to FIGS. 1, 3, and 11. When the power storage system 1 is discharged, the power conditioner 10 designates the minimum voltage of the first voltage values of the power storage devices 20A, 20B, and 20C as the second voltage value and discharges the control signal to the power storage devices 20A, 20B, and 20C. Send to 20C. When the power storage devices 20A, 20B, and 20C receive the discharge control signal, the first voltage values Va, Vb, and Vc applied to the respective power storage units 22 are compared with the second voltage value V2 included in the control signal. . The power storage devices 20A, 20B, and 20C discharge the first voltage value and the second voltage value if the difference between the first voltage value and the second voltage value is within a predetermined range. If the difference between the voltage values is not within a predetermined range, discharging is performed by stepping down from the first voltage value to the second voltage value. When the discharge of each power storage device 20 proceeds and the first voltage value of all the power storage devices 20 becomes equal to the second voltage value, the power storage device 20 discharges at the first voltage value without being transformed. Thereafter, each power storage device ends the discharge when the discharge end condition is satisfied. The discharge process by the power storage device 20 including the switching unit 25 of the configuration example 3 is the same as the discharge process by the power storage device 20 including the switching unit 25 of the configuration example 2 described above with reference to FIG.

  With reference to FIGS. 1, 4, and 13, an operation example during charging of the power storage system 1 in which the power storage device 20 includes the switching unit 25 of the configuration example 3 will be described. First voltage values Va, Vb, and Vc when power storage devices 20A, 20B, and 20C are charged to full charge are set to maximum voltage values Vamax, Vbmax, and Vcmax. The power conditioner 10 performs constant current control until any of the power storage devices 20 to be charged reaches the maximum voltage value, and performs constant voltage control when it reaches the maximum voltage value. Therefore, at the time of charging the power storage system 1, the power conditioner 10 designates the minimum value of the first voltage values of the power storage devices 20A, 20B, and 20C as the second voltage value to charge the power storage device 20A. , 20B and 20C.

  Constant current control is performed in the initial stage of charging. At time t1 in FIG. 13, the same voltage is applied to the first voltage values Va, Vb, and Vc of the power storage devices 20A, 20B, and 20C until the first voltage value Vc of the power storage device 20C reaches Vcmax. Therefore, the charging proceeds with the second voltage value V2 = Va = Vb = Vc. Each of the power storage devices 20A, 20B, and 20C compares the first voltage values Va, Vb, and Vc applied to the power storage unit 22 of the own device with the second voltage value V2 included in the control signal. Since each of the power storage devices 20A, 20B, and 20C has a difference between the first voltage value and the second voltage value within a predetermined range, charging is performed at the second voltage value without boosting the switching unit 25. carry out.

  After that, when the first voltage value Vc of the power storage device 20C reaches the maximum voltage value Vcmax at time t1, the first voltage value Vc of the power storage device 20C cannot increase any further, so the first voltage value of the power storage device 20C The difference between the value Vc and the second voltage value V2 exceeds a predetermined range. Thereafter, the power conditioner 10 transmits a control signal for charging by specifying the first voltage value Vc = Vcmax of the power storage device 20C as the second voltage value, so that constant voltage control by trickle charging to compensate for natural discharge is performed. Is done. On the other hand, since the power storage devices 20A and 20B have the second voltage value V2 = Vc <Vb <Va after the time t1, the input power is set to the second voltage value V2 and the power supply devices up to the time t1. The voltage is boosted to the first voltage value Va or Vb that maintains constant current control. When the first voltage value Vb reaches the maximum voltage value Vbmax at time t2, the power storage device 20B cannot increase the first voltage value Vb any more, so the input power is changed from the second voltage value V2 to the second voltage value V2. The voltage is boosted to a voltage value Vb of 1. Therefore, the power storage device 20B is subjected to constant voltage control by trickle charging to compensate for natural discharge until the charging termination condition is satisfied. Similarly, when the first voltage value Va reaches the maximum voltage value Vamax at the time te, the power storage device 20A boosts the input power from the second voltage value V2 to the first voltage value Va thereafter. Constant voltage control is performed.

(Processing example 4 of power storage device)
With reference to FIG. 14, an example of a process executed by the power storage device 20 that is the power storage device according to an embodiment of the present disclosure will be described. This process is a charging process by the power storage device 20 including the switching unit 25 of the configuration example 3.

  Step S501: The control unit 21 measures the first voltage value by the measurement unit 23.

  Step S502: The control unit 21 transmits a signal indicating the first voltage value.

  Step S503: The control unit 21 receives a signal indicating the second voltage value.

  Step S504: The control unit 21 determines whether or not the potential difference between the first voltage value and the second voltage value is within a predetermined range.

  Step S505: When the potential difference is within the predetermined range (step S504—Yes), the control unit 21 performs charging without increasing the voltage by the switching unit 25.

  Step S506: When the potential difference is not within the predetermined range (step S504-No), the control unit 21 determines whether or not the potential difference between the first voltage value and the maximum voltage value is within the predetermined range.

  Step S507: When the potential difference is within the predetermined range (step S506-Yes), the control unit 21 boosts the voltage by the switching unit 25 and performs charging by constant voltage control.

  Step S508: When the potential difference is not within the predetermined range (step S506-No), the control unit 21 boosts the voltage by the switching unit 25 and performs charging by constant current control.

  Step S509: The control unit 21 determines whether or not a charging termination condition is satisfied. When the end condition is satisfied (step S509-Yes), the control unit 21 ends this process. When the end condition is not satisfied (step S509-No), the control unit 21 repeats the process from S501.

(Operation example 4 of power storage system)
With reference to FIG. 1, FIG. 5, and FIG. 15, the operation example at the time of discharge of the electrical storage system 1 with which the electrical storage apparatus 20 is provided with the switching part 25 of the structural example 4 is demonstrated. At the time of discharging the power storage system 1, the power conditioner 10 designates the maximum voltage of the first voltage value of the power storage devices 20A, 20B and 20C as the second voltage value and discharges a control signal to the power storage devices 20A, 20B and 20C. Send to 20C. In the operation example 3 of the power storage system 1 described above, the minimum value of the first voltage value of the power storage device 20 is designated as the second voltage value, whereas in this operation example, the maximum value is the second voltage value. Since the value is specified, voltage control is performed on the power storage device 20 in the direction opposite to that of the operation example 3. In FIG. 15, the power conditioner 10 sets the second voltage value V <b> 2 to Va when starting the discharging of the power storage system 1 at time ts. When the power storage devices 20A, 20B, and 20C receive the discharge control signal, the first voltage values Va, Vb, and Vc applied to the respective power storage units 22 are compared with the second voltage value V2 included in the control signal. . The power storage devices 20A, 20B, and 20C discharge the first voltage value and the second voltage value if the difference between the first voltage value and the second voltage value is within a predetermined range. If the difference between the voltage values is not within a predetermined range, the discharge is performed by increasing the voltage from the first voltage value to the second voltage value. The power storage device 20A discharges at the first voltage value Va without being transformed after the time ts. The power storage device 20B increases the voltage from the first voltage value Vb to the second voltage value V2 from time ts to time t1, and discharges. At time t1, the potential difference between the self device and the power storage device 20A is a predetermined value. If it falls within the range, after that, discharging is performed at the first voltage value Vb without being transformed. Similarly, the power storage device 20C increases the voltage from the first voltage value Vc to the second voltage value V2 from time ts to time t2, and performs discharging. When the potential difference between the power storage device 20C and the power storage devices 20A and 20B falls within a predetermined range at time t2, the power storage device 20C discharges at the first voltage value Vb without being transformed thereafter. After the time t2, the power storage devices 20A, 20B, and 20C discharge without being transformed, and when the discharge termination condition is satisfied, the discharge ends.

(Processing example 5 of power storage device)
With reference to FIG. 16, an example of processing executed by the power storage device 20 that is the power storage device according to an embodiment of the present disclosure will be described. This process is a discharge process performed by the power storage device 20 including the switching unit 25 of the configuration example 4.

  Step S <b> 601: The control unit 21 measures the first voltage value by the measurement unit 23.

  Step S602: The control unit 21 transmits a signal indicating the first voltage value.

  Step S603: The control unit 21 receives a signal indicating the second voltage value.

  Step S604: The control unit 21 determines whether or not the potential difference between the first voltage value and the second voltage value is within a predetermined range.

  Step S605: When the potential difference is within the predetermined range (step S604-Yes), the control unit 21 performs discharge without increasing the voltage by the switching unit 25.

  Step S606: When the potential difference is not within the predetermined range (Step S604-No), the control unit 21 boosts the voltage by the switching unit 25 and performs discharge.

  Step S607: The control unit 21 determines whether or not a discharge termination condition is satisfied. When the end condition is satisfied (step S607-Yes), the control unit 21 ends this process. When the termination condition is not satisfied (step S607-No), the control unit 21 repeats this process from S601.

  With reference to FIGS. 1, 5, and 17, an operation example during charging of the power storage system 1 in which the power storage device 20 includes the switching unit 25 of the configuration example 3 will be described. When the power storage system 1 is charged, the power conditioner 10 designates the maximum value of the first voltage value of the power storage devices 20A, 20B and 20C as the second voltage value and charges the power storage devices 20A, 20B and 20C. Send to 20C. In the operation example 3 of the power storage system 1 described above, the minimum value of the first voltage value of the power storage device 20 is designated as the second voltage value, whereas in this operation example, the maximum value is the second voltage value. Since the value is specified, voltage control in the direction opposite to that of the operation example 3 is performed on the power storage device 20. When the power storage system 1 is charged, the power conditioner 10 designates the maximum value of the first voltage value of the power storage devices 20A, 20B and 20C as the second voltage value and charges the power storage devices 20A, 20B and 20C. Send to 20C. First voltage values Va, Vb, and Vc when power storage devices 20A, 20B, and 20C are charged to full charge are set to maximum voltage values Vamax, Vbmax, and Vcmax. The power conditioner 10 performs constant current control until all the power storage devices 20 to be charged reach their maximum voltage values, and performs constant voltage control when they reach the maximum voltage value. Each power storage device 20 is charged at the second voltage value V2 without being stepped down until the first voltage value reaches the maximum voltage value. When the first voltage value reaches the maximum voltage value, each power storage device 20 performs charging by stepping down charging of the own device to the first voltage value. The power storage device 20C does not step down until the first voltage value Vc reaches the maximum voltage value Vcmax at time t1, and continues charging with the second power storage device V2, and after time t1, the second voltage value V2 To the first voltage value Vc to perform charging. The power storage device 20B does not step down until the first voltage value Vb reaches the maximum voltage value Vbmax at time t2, and continues to be charged with the second power storage device V2, and after time t2, the second voltage value V2 To the first voltage value Vb to perform charging. The power storage device 20A continues to be charged with the second voltage value V2 without being stepped down until the first voltage value Va reaches the maximum voltage value Vamax at time te. Since the second voltage value V2 is equal to the first voltage value Va after the time t2, the power storage device 20A continues to be charged with the second voltage value V2 without being stepped down.

(Processing example 6 of power storage device)
With reference to FIG. 18, an example of a process executed by the power storage device 20 that is the power storage device according to an embodiment of the present disclosure will be described. This process is a charging process performed by the power storage device 20 including the switching unit 25 of the configuration example 4.

  Step S <b> 701: The control unit 21 measures the first voltage value by the measurement unit 23.

  Step S702: The control unit 21 transmits a signal indicating the first voltage value.

  Step S703: The control unit 21 receives a signal indicating the second voltage value.

  Step S704: The control unit 21 determines whether or not the potential difference between the first voltage value and the second voltage value is within a predetermined range.

  Step S705: When the potential difference is within the predetermined range (step S704-Yes), the control unit 21 performs charging without stepping down by the switching unit 25.

  Step S706: When the potential difference is not within the predetermined range (step S704-No), the control unit 21 determines whether or not the potential difference between the first voltage value and the maximum voltage value is within the predetermined range.

  Step S707: When the potential difference is within the predetermined range (step S706-Yes), the control unit 21 steps down the voltage at the switching unit 25 and performs charging by constant voltage control.

  Step S708: When the potential difference is not within the predetermined range (step S706-No), the control unit 21 steps down the voltage at the switching unit 25 and performs charging by constant current control.

  Step S709: The control unit 21 determines whether or not a charging termination condition is satisfied. When the end condition is satisfied (step S709-Yes), the control unit 21 ends the process. When the termination condition is not satisfied (step S709-No), the control unit 21 repeats this process from S701.

  As described above, according to the present embodiment, the power storage device 20 includes the terminal unit 24, the power storage unit 22, the terminal unit 24, and the power storage unit 22 that are connected in parallel to other power storage devices via electric wires. A switching unit 25 provided between the measuring unit 23, a measuring unit 23 that measures the first voltage value applied to the power storage unit 22, a communication unit 27 that receives a signal indicating the second voltage value applied to the terminal unit 24, The control part 21 which controls the switching part 25 based on a 1st voltage value and a 2nd voltage value is provided. According to this configuration, the power storage device 20 can control charging / discharging of its own device according to the voltage value of the power charged / discharged by the other power storage devices 20 connected in parallel. Therefore, a plurality of power storage devices 20 with different voltage values of power storage unit 22 or a plurality of power storage devices 20 with different degrees of deterioration of power storage unit 22 can be connected in parallel. Thereby, the power storage system 1 to which the power conditioner 10 and the power storage device 20 that have already been operated are connected to a new storage battery or a power storage device having a power storage unit 22 having a degree of deterioration different from that of the existing power storage device 20. It can be expanded. Thus, the usefulness of the technique of charging / discharging electric power to a plurality of power storage devices having different voltage values is improved.

  According to the present embodiment, the control unit 21 of the power storage device 20 controls the switching unit 25 to switch the power input / output between the terminal unit 24 and the power storage unit 22. According to this configuration, the power storage device 20 can implement and stop charging / discharging of the power storage device 20 according to the voltage value of the power charged / discharged by the other power storage devices 20 connected in parallel. Thereby, the usefulness of the technique which charges / discharges electric power to the some electrical storage apparatus from which a voltage value differs is improved.

  According to the present embodiment, the control unit 21 of the power storage device 20 controls the switching unit 25 to transform power input / output between the terminal unit 24 and the power storage unit 22. According to this configuration, the power storage device 20 can transform the voltage value of the power charged / discharged by the power storage device 20 according to the charge / discharge voltage value of the other power storage device 20 connected in parallel. Thereby, the usefulness of the technique of charging / discharging electric power to a plurality of power storage devices having different voltage values is improved.

  According to the present embodiment, the signal indicating the second voltage value includes the voltage value applied to the power storage unit 22 of another power storage device 20. According to such a configuration, the control unit 21 of the power storage device 20 can calculate the second voltage value by itself based on the voltage value applied to the power storage unit 22 of the other power storage device 20 included in the received signal. it can. Thereby, for example, even when other devices included in the power storage system 1 such as the power conditioner 10 do not have the function of calculating the second voltage value, the processing according to the present disclosure can be performed, and the voltage values are different. Usefulness of a technique for charging / discharging electric power to a plurality of power storage devices is improved.

  Although the foregoing embodiments have been described as representative examples, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the disclosure. Accordingly, the present disclosure should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, functions and the like included in each means or each step can be rearranged so as not to be logically contradictory, and a plurality of means or steps can be combined into one or divided. .

  For example, in the above-described embodiment, the plurality of power storage devices 20 included in the power storage system 1 have been described as having the same design capacity although there are differences due to aging, but this is not restrictive. In the power storage system 1 of the present disclosure, a plurality of power storage devices 20 having different design capacities may be connected in parallel from this place regardless of aging degradation.

  For example, in the above-described embodiment, the power storage device may be any device that can supply power to the outside and charge the power from the outside. The power storage device may include an arbitrary power supply device including, for example, a solar battery, a wind power generator, a hydroelectric generator, a fuel cell, and the like. In such a case, the power storage unit of the power storage device described above may be a combination of a power supply device that generates power and supplies power and a power storage device that charges and discharges power.

  For example, in the above-described embodiment, the power storage device 20 receives a signal indicating the second voltage value in the communication unit 27 and controls the switching unit 25 based on the first voltage value and the second voltage value. An example is shown, but this is not the case. The power storage device 20 includes a second measurement unit 35 that measures a first current value input / output by the power storage unit 22 of the self-device, and receives a signal indicating the second current value in the communication unit 27, The switching unit 25 may be controlled based on the current value and the second current value. Hereinafter, an embodiment in which the switching unit 25 controls the power storage device 20 based on the first current value and the second current value will be described.

  The second measuring unit 35 measures a current value input / output by the power storage unit 22. The second measuring unit 35 may be an ammeter. In this specification, the current value input and output by the power storage unit 22 measured by the second measurement unit 35 is also referred to as a first current value. The second measurement unit 35 transmits the measured current value to the control unit 21. The 2nd measurement part 35 may be installed in arbitrary positions. For example, the second measuring unit 35 may be installed in the vicinity of the switch 26 of the electric wire 31A.

  The control unit 21 receives a signal indicating the second current value through the communication unit 27. The control unit 21 may receive the signal by any method. For example, the control unit 21 may receive a signal indicating the second current value transmitted by another device at a predetermined time interval or the like. Or the control part 21 transmits the transmission request | requirement of the signal which shows a 2nd electric current value to another apparatus by the communication part 27, and the signal which shows the 2nd electric current value which the other apparatus transmitted based on the said transmission request May be received.

  The signal indicating the second current value may include the second current value or information used for calculating the second current value. For example, the signal indicating the second current value includes the second current value calculated by the power conditioner 10 based on the current value input / output by the power storage unit 22 of the power storage device 20 included in the power storage system 1. It may be. In such a case, the second current value can be measured by, for example, an ammeter that measures the current of the electric wire 31 </ b> A included in each power storage device 20. The second current value may be, for example, the maximum value, the minimum value, or the average value of the current values input / output by the power storage units 22 of the respective power storage devices 20. An equal second current value may be set in the signal indicating the second current value transmitted to each power storage device 20, and a different second current value is set for each power storage device 20. Also good. The control unit 21 of each power storage device 20 controls its own device so as to discharge or charge based on the second current value. Further, the signal indicating the second current value may include information used for calculating the second current value. In such a case, the control unit 21 of the power storage device 20 may calculate the second current value from information used to calculate the received second current value. The control unit 21 of the power storage device 20 controls the own device so as to perform discharging or charging based on the calculated second current value. The information used to calculate the second current value includes, for example, the voltage value or current value measured by the other power storage device 20, or the SOC or SOH of the power storage unit 22 of the other power storage device 20 described above. Etc. may be included.

  The signal indicating the second current value may include other information in addition to the above-described second current value or information used to calculate the second current value. For example, the signal indicating the second current value may include a control command for causing the power storage device to perform an operation such as charging or discharging. Accordingly, the signal indicating the second current value can be used as, for example, a control signal for discharging by designating the second current value, or a control signal for charging by designating the second current value. The other information may further include arbitrary information such as an operation start condition and an end condition, a control start time and an end time, or a control duration. Accordingly, a more detailed control instruction can be transmitted to power storage device 20 using the signal indicating the second current value.

  The control unit 21 controls the switching unit 25 based on the first current value and the second current value, and transforms the power input / output between the terminal unit 24 and the power storage unit 22. Good. For example, the control unit 21 may calculate the difference between the first current value and the second current value. Hereinafter, the difference between the first current value and the second current value is also simply referred to as a current value difference. When it is determined that the current value difference is not within the predetermined range, the control unit 21 increases or decreases the power input to the switching unit 25 so that the current value difference falls within the predetermined range. The switching unit 25 may be controlled. When it is determined that the difference between the current values is within a predetermined range, the control unit 21 may control the switching unit 25 so that the power input to the switching unit 25 is output as it is without being transformed.

  For example, when the control unit 21 of the power storage device 20A receives a control signal for discharging by designating a second current value larger than the first current value of the own device, the control unit 21 sets the first current value by the switching unit 25. Electric power is boosted so that the difference from the second current value is within a predetermined range, and discharging is performed. After that, after the potential difference between the first current value and the second current value of the own device falls within a predetermined range, when receiving a control signal for discharging by designating the second current value, the control unit 21 Then, discharging is performed without increasing the power by the switching unit 25. As a result, even when the voltages of the power storage units 22 of the respective power storage devices 20 included in the power storage system 1 are different, the power storage system 1 externally supplies a current combined with the current output to each power storage device 20. Can be supplied.

  According to such a configuration, the power storage system 1 can supply a current exceeding the maximum discharge current value of each power storage device 20 included in the power storage system 1 to the outside. With reference to FIG. 19, operation | movement of the electrical storage system 1 in the initial stage of discharge is demonstrated. For example, power storage system 1 includes power storage devices 20A and 20B each having a maximum discharge current value of 1.5A. In FIG. 19, the power storage system 1 controls the current from the power storage device 20A having a high voltage at the discharge start time ts of the power storage devices 20A and 20B to be larger than the current from the power storage device 20B having a low voltage. The power storage system 1 causes the power storage devices 20A and 20B to control the switching unit 25, and causes the power storage device 20A to output a current of 1.5A and the power storage device 20B to output a current of 0.5A. Supply current to the outside. Thereafter, when the discharge of the power storage devices 20A and 20B progresses and the voltages of both become uniform at time tm, the power storage system 1 ends the control of the switching unit 25 to the power storage devices 20A and 20B, and the power storage devices 20A and 20B. By supplying a current of 1.0 A equally from each, the supply of a total current of 2.0 A may be maintained after time tm.

  With reference to FIG. 20, the operation of power storage system 1 at the end of discharge will be described. For example, power storage system 1 includes power storage devices 20A and 20B each having a maximum discharge current value of 1.5A. Further, it is assumed that the power storage devices 20A and 20B end the discharge when the voltage values become Vaend and Vbend, respectively. Hereinafter, the voltage values Vaend and Vbend are also referred to as end-of-discharge voltage values. In FIG. 20, the power storage system 1 does not allow the power storage devices 20A and 20B to control the switching unit 25 until time td, and outputs a current of 1.0 A equally from each power storage device 20A and 20B. Supply the current of 0A to the outside. At time td, the power storage system 1 controls the current from the power storage device 20B having a low end-of-discharge voltage value of the power storage devices 20A and 20B to be larger than the current from the power storage device 20A having a high end-of-discharge voltage value. . The power storage system 1 causes the power storage devices 20A and 20B to control the switching unit 25 to output a current of 0.5 A to the power storage device 20A and a current of 1.5 A to the power storage device 20B, so that the total after time td is totaled. The supply of 2.0 A current to the outside may be maintained. Thereafter, the power storage system 1 may cause the power storage devices 20A and 20B to output current until the voltage value of the power storage devices 20A and 20B reaches the end-of-discharge voltage value at time te. As described above, in the power storage system 1, each of the power storage devices 20 included in the power storage system 1 may be controlled to discharge so as to reach the end-of-discharge voltage value equally.

DESCRIPTION OF SYMBOLS 1 Power storage system 10 Power conditioner 20 Power storage apparatus 21 Control part 22 Power storage part 23 Measurement part 24 Terminal part 25 Switching part 26 Switch 27 Communication part 28 Storage part 29 Notification part 30 Input part 31 Electric wire 32 Switching element 33 Coil 34 Diode 40 Electric wire 50 Communication line 60 Power system 70 Load

Claims (6)

A terminal portion connected in parallel with another power storage device via an electric wire;
A power storage unit;
A switching unit provided between the terminal unit and the power storage unit;
A measurement unit for measuring a first voltage value applied to the power storage unit;
A communication unit that receives a signal indicating a second voltage value applied to the terminal unit;
A control unit that controls the switching unit based on the first voltage value and the second voltage value;
A power storage device. The power storage device according to claim 1,
The said control part is a electrical storage apparatus which controls the said switching part and switches the input / output of the electric power of the said terminal part and the said electrical storage part. The power storage device according to claim 1 or 2,
The said control part is an electrical storage apparatus which controls the said switching part and transforms the electric power input / output between the said terminal part and the said electrical storage part. The power storage device according to any one of claims 1 to 3,
The signal indicating the second voltage value includes a voltage value applied to a power storage unit of the other power storage device. A power storage unit comprising: a terminal unit connected in parallel to another power storage device via an electric wire; a power storage unit; a switching unit provided between the terminal unit and the power storage unit; a measurement unit; and a communication unit. A control device capable of controlling the device,
Causing the power storage device to measure a first voltage value applied to the power storage unit by the measurement unit;
Causing the power storage device to receive a signal indicating a second voltage value applied to the terminal unit by the communication unit;
A control device that causes the power storage device to control the switching unit based on the first voltage value and the second voltage value. A power storage unit comprising: a terminal unit connected in parallel to another power storage device via an electric wire; a power storage unit; a switching unit provided between the terminal unit and the power storage unit; a measurement unit; and a communication unit. An apparatus control method comprising:
Measuring a first voltage value applied to the power storage unit by the measuring unit;
Receiving a signal indicating a second voltage value applied to the terminal unit by the communication unit;
Controlling the switching unit based on the first voltage value and the second voltage value;
Including a control method.