JP2019158666A - Method for determining degradation, degradation determination device, and degradation determination system - Google Patents

Abstract

To provide a method for determining a degradation, a degradation determination device, and a degradation determination system which can detect, in an early stage, a power storage element which degrades relatively quickly.SOLUTION: The method for determining a degradation in a power storage element determines whether a power storage element which degrades relatively quickly has already degraded by stopping conduction to a power storage unit including a plurality of power storage elements, stopping equalization of voltages to the power storage elements, acquiring a change of the voltage of the power storage elements with time, and determining the presence of a degradation based on the acquired time change.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a deterioration determination method, a deterioration determination device, and a deterioration determination system for determining the presence or absence of a power storage element whose progress of deterioration is relatively fast.

  Energy storage devices are widely used in uninterruptible power supply devices, DC or AC power supply devices included in a stabilized power supply, and the like. In addition, the use of power storage elements in large-scale systems that store generated power is expanding. In this specification, a power storage element refers to all elements that store power. The minimum unit of a power storage element is called a power storage cell.

  The power storage module is configured by connecting a plurality of power storage cells in series and / or in parallel. It is known that a power storage cell is deteriorated by repeating charge and discharge. Patent Document 1 uses a database storing deterioration rate prediction values corresponding to a plurality of use conditions of a storage battery, and use conditions and deterioration rate data obtained from a storage battery that is actually operating. A technique for performing life prediction is disclosed.

  In a power storage module including a power storage cell, individual differences such as a difference in self-discharge and a difference in deterioration rate exist between the individual power storage cells. For example, when charging or using a power storage module including a power storage cell in which the progress of deterioration is relatively fast (faster than expected), voltage variation or charge state variation occurs between the power storage cells. Patent Document 2 discloses a technique for equalizing voltages or charge states of a plurality of power storage cells in order to suppress such variations.

JP, 2015-121520, A Japanese Patent No. 5573075

  In the case where a power storage cell that includes a relatively fast progress of deterioration (hereinafter referred to as a deteriorated power storage cell) is included in the power storage module, the performance of the power storage module is limited by the deteriorated power storage cell. Furthermore, the performance of the entire power storage system incorporating the power storage module is affected. Therefore, in order to maintain the performance of the power storage system, it is desirable to detect a deteriorated power storage cell at an early stage. However, even in a power storage cell in which the progress of deterioration is relatively fast, the progress of the initial deterioration is often slow. When the function of equalizing the voltages or the charge states of the plurality of storage cells is working, the difference in behavior between the deteriorated storage cell and the normal storage cell becomes small, and it is difficult to detect the deteriorated storage cell. After a deteriorated power storage cell cannot be detected at an early stage and a decrease in the performance of the power storage system becomes apparent, it may take time to investigate the cause, and the time for stopping the power storage system may become longer.

  An object of the present invention is to provide a deterioration determination method, a deterioration determination device, and a deterioration determination system capable of early detection of a power storage element in which the progress of deterioration is relatively fast.

  In the deterioration determination method according to one aspect of the present invention, energization of a power storage element unit including a plurality of power storage elements is stopped, voltage equalization of the plurality of power storage elements is stopped, and time of voltage of the plurality of power storage elements is determined. The change is acquired, and the presence or absence of a deteriorated power storage element whose progress of deterioration is fast is determined based on the acquired time change of the voltage. A power storage cell or a power storage module may correspond to a power storage element, and a power storage module or a bank described later may correspond to a power storage element unit.

  In the present invention, it is possible to determine whether or not a power storage element is a deteriorated power storage element more easily than in the past, and it is possible to detect a deteriorated power storage element at an early stage. Therefore, it is possible to remove the deteriorated power storage element before the performance of the power storage system is significantly deteriorated.

It is a figure which shows the outline | summary of a deterioration determination system. It is a block diagram which shows the structural example of a deterioration determination system. It is a block diagram which shows the structural example of an electrical storage system. It is a block diagram which shows the structural example of an electrical storage module. It is a graph which shows typically the time change of the voltage of an electrical storage cell in the state where a balance circuit operates. It is a block diagram which shows the function structural example of the battery management apparatus which concerns on Embodiment 1, and a management apparatus. It is a graph which shows typically the time change of the voltage of an electrical storage cell in the state where voltage equalization is not performed. It is a flowchart which shows the procedure of the process which determines the presence or absence of a degradation electrical storage element. It is a block diagram which shows the function structural example of the battery management apparatus which concerns on Embodiment 2, and a management apparatus. It is a block diagram which shows the function structural example of the battery management apparatus which concerns on Embodiment 3. FIG.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(Embodiment 1)
FIG. 1 is a diagram showing an overview of the deterioration determination system 100. As shown in FIG. 1, a communication network N including a public communication network (for example, the Internet) N1 and a carrier network N2 that implements wireless communication based on mobile communication standards includes a thermal power generation system F, a solar power generation system S, wind power generation. A system R, an uninterruptible power supply (UPS) U, and a rectifier (DC power supply apparatus or AC power supply apparatus) D disposed in a stabilized power supply system for railways are connected. The communication network N is connected to a communication device 1 (see FIG. 2), which will be described later, a server device 2 that collects information from the communication device 1, a client device 3 that acquires the collected information, and the like.

  The carrier network N2 includes a base station BS. The client device 3 can communicate with the server device 2 via the communication network N from the base station BS. An access point AP is connected to the public communication network N1. The client device 3 can transmit / receive information to / from the server device 2 via the communication network N from the access point AP.

  The solar power generation system S, the thermal power generation system F, and the wind power generation system W are provided with a power conditioner (PCS) P and a power storage system 101. The power storage system 101 is configured by arranging a plurality of containers C accommodating the power storage module group L in parallel. The power storage module group L has, for example, a hierarchical structure of a power storage module in which a plurality of power storage cells are connected in series, a bank in which a plurality of power storage modules are connected in series, and a domain in which a plurality of banks are connected in parallel. The storage cell or storage module 60 (see FIG. 3) corresponds to a storage element, and the storage module 60 or bank 4 (see FIG. 3) corresponds to a storage element unit. The storage element is preferably a rechargeable element such as a secondary battery such as a lead storage battery and a lithium ion battery, or a capacitor. A part of the power storage element may be a primary battery that cannot be recharged.

  FIG. 2 is a block diagram illustrating a configuration example of the deterioration determination system 100. The deterioration determination system 100 includes a communication device 1, a server device 2 as a deterioration determination device, a client device 3, and a power storage system 101 (see FIG. 3). The power storage system 101 includes a management device M described later. The management device M manages power storage elements included in the power storage system 101. The power storage system 101 is not limited to the one installed in the power generation system. The power storage system 101 may be connected to the power transmission system via the power conditioner P.

  As shown in FIG. 2, the communication device 1 is connected to a communication network N and is connected to target devices P, U, D, and M. The target devices P, U, D, and M are devices to be managed by the deterioration determination system 100. The target devices P, U, D, and M include a power conditioner P, an uninterruptible power supply device U, a rectifier D, and a management device M.

  In the deterioration determination system 100, the state (for example, voltage, current, temperature, state of charge (SOC)) of power storage elements included in the power storage system 101 using the communication device 1 connected to each target device P, U, D, M. ) Is monitored. In addition, the presence / absence of a degraded power storage element having a relatively high rate of degradation is determined. The degradation determination system 100 presents the detected state (including degradation state, abnormal state, etc.) of the storage cell so that the user or operator (maintenance staff) can confirm.

  The communication device 1 includes a control unit 10, a storage unit 11, a first communication unit 12, and a second communication unit 13. The control unit 10 includes a CPU (Central Processing Unit) and the like, and controls the entire communication device 1 using a built-in memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

  The storage unit 11 is nonvolatile. The storage unit 11 is configured using, for example, a nonvolatile memory such as a flash memory. The storage unit 11 stores a device program 1P that is read and executed by the control unit 10. The storage unit 11 stores information collected by processing of the control unit 10 and information such as an event log.

  The first communication unit 12 is a communication interface that realizes communication with the target devices P, U, D, and M. The first communication unit 12 is configured using a serial communication interface such as RS-232C or RS-485, for example. The second communication unit 13 is an interface that realizes communication via the communication network N. The second communication unit 13 is configured using, for example, a communication interface such as Ethernet (registered trademark) or a wireless communication antenna. The control unit 10 can communicate with the server device 2 via the second communication unit 13.

  The server device 2 includes a control unit 20, a storage unit 21, a communication unit 22, and a learning model 23. The server device 2 may be a single server computer or may be composed of a plurality of server computers.

  The control unit 20 is constituted by a CPU, for example. The control unit 20 controls the entire server device 2 using a built-in memory such as a ROM and a RAM. The control unit 20 may be configured using a CPU and a GPU (Graphics Processing Unit), a multi-core CPU, or a TPU (Tensor Processing Unit). The control unit 20 executes information processing based on the server program 2P stored in the storage unit 21. The server program 2P includes a web server program. The control unit 20 functions as a Web server that executes provision of a Web page to the client device 3, acceptance of login to the Web service, and the like. The control unit 20 can also collect information from the communication device 1 as an SNMP (Simple Network Management Protocol) server based on the server program 2P.

  As the storage unit 21, for example, a nonvolatile memory such as a flash memory or a hard disk can be used. The storage unit 21 stores data including the states of the target devices P, U, D, and M to be monitored collected by the processing of the control unit 20. The communication unit 22 is a communication device that realizes communication connection and data transmission / reception via the communication network N. Specifically, the communication unit 22 is a network card corresponding to the communication network N.

  The learning model 23 can determine the presence / absence of the degraded storage element based on the input data regarding the storage element collected from the target devices P, U, D, and M via the communication device 1. The learning model 23 includes, for example, an algorithm for machine learning including deep learning. For example, the learning model 23 may be realized using a CPU, a RAM, and a computer program that is stored in a nonvolatile storage unit, loaded into the RAM, and executed by the CPU. The learning model 23 may be realized using a quantum computer.

  The client device 3 may be a computer used by an operator such as an administrator of the power storage system 101 and a maintenance staff of the target devices P, U, D, and M. The client device 3 may be a desktop or laptop personal computer, or may be a smartphone or tablet communication terminal. The client device 3 includes a control unit 30, a storage unit 31, a communication unit 32, a display unit 33, and an operation unit 34.

  The control unit 30 is a processor using a CPU. The control unit 30 causes the display unit 33 to display a web page provided by the server device 2 or the communication device 1 based on the web browser program stored in the storage unit 31.

  As the storage unit 31, for example, a nonvolatile memory such as a flash memory or a hard disk is used. The storage unit 31 stores various programs including a web browser program. The communication unit 32 is, for example, a communication device such as a network card for wired communication, a wireless communication device for mobile communication connected to the base station BS (see FIG. 1), or a wireless communication device corresponding to connection to the access point AP. Can be used. The control unit 30 can perform communication connection or information transmission / reception with the server device 2 or the communication device 1 via the communication network N by the communication unit 32.

  The display unit 33 may be a display such as a liquid crystal display or an organic EL (Electro Luminescence) display. The display unit 33 can display an image of a Web page provided by the server device 2 by processing based on the Web browser program of the control unit 30.

  The operation unit 34 is a user interface such as a keyboard and pointing device that can be input and output with the control unit 30, or a voice input unit. The operation unit 34 may be a touch panel of the display unit 33 or a physical button provided on the housing. The operation unit 34 notifies the control unit 20 of operation information by the user.

  FIG. 3 is a block diagram illustrating a configuration example of the power storage system 101. The power storage system 101 has a hierarchical structure of a power storage module 60 in which a plurality of power storage cells are connected in series, a bank 4 in which the plurality of power storage modules 60 are connected in series, and a domain in which the plurality of banks 4 are connected in parallel. The power storage system 101 shown in FIG. 3 constitutes one domain.

  The power storage system 101 is connected to the power conditioner P. Each of the plurality of banks 4 is connected to the power conditioner P through the power line 42. Electric power is supplied to the bank 4 through the power conditioner P, and the bank 4 is charged. Further, the electric power discharged from the bank 4 is output to the outside through the power conditioner P. For example, the power conditioner P is connected to the power generation system and / or the power transmission system.

  Each bank 4 includes a switch 41. The switch 41 performs connection and disconnection between the plurality of power storage modules 60 connected in series and the power line 42. When the switch 41 is closed, the plurality of power storage modules 60 and the power line 42 are connected, and when the switch 41 is opened, the plurality of power storage modules 60 and the power line 42 are disconnected. In a state where the plurality of power storage modules 60 and the power line 42 are connected, charging or discharging, that is, energization is performed in each power storage module 60 through the power conditioner P, the power line 42, and the switch 41.

  Each bank 4 includes a plurality of power storage modules 60 and a battery management unit (BMU: Battery Management Unit) 50. Each power storage module 60 includes a control board (CMU: Cell Monitoring Unit) 70. The control board 70 provided in each power storage module 60 is connected to the battery management device 50. The battery management device 50 can communicate with each control board 70. The battery management device 50 is supplied with power through a path (not shown) different from the power line 42 and can operate regardless of the state of the switch 41.

  The power storage system 101 includes a management device M. The management device M is a BMU that manages power storage elements belonging to a domain. The battery management device 50 provided in each bank 4 is connected to the management device M via the communication line 43. The communication device 1 is connected to the management apparatus M and / or the power conditioner P. The communication device 1 may include a communication device connected to the management apparatus M and a communication device connected to the power conditioner P. The battery management device 50 transmits and receives information to and from the management device M. The management apparatus M aggregates information from the plurality of battery management apparatuses 50 and outputs the information to the communication device 1.

  FIG. 4 is a block diagram illustrating a configuration example of the power storage module 60. The control board 70 included in the power storage module 60 includes a balanced circuit (balancer) 71, a drive unit 73, a voltage acquisition unit 74, a control unit 75, a storage unit 76, and a communication unit 77. The plurality of power storage cells 61a to 61e included in the power storage module 60 are connected in series. In FIG. 4, for convenience, five power storage cells connected in series are shown, but the number of power storage cells constituting the power storage module 60 is not limited to five. In addition, the power storage module 60 may include power storage cells connected in parallel to other power storage cells. The plurality of power storage cells 61 a to 61 e are electrically connected in series to the power storage cells included in the other power storage module 60 and are electrically connected to the switch 41.

  The balanced circuit 71 is connected in parallel to the storage cell 61a, a series circuit of a resistor 71a and a switch 72a, connected in parallel to the storage cell 61b, and connected in parallel to the storage cell 61b, and connected in parallel to the storage cell 61c. A resistor 71c and a switch 72c connected in parallel; a capacitor 71d connected in parallel; a resistor 71d and a switch 72d connected in series; and a capacitor 71e connected in parallel to a resistor 71e and a switch A series circuit with 72e is provided. For the switches 72a to 72e, a switching element such as an FET (Field Effect Transistor) or a switching circuit such as a relay may be used.

  The drive unit 73 drives so that the switches 72a to 72e are turned on or off. When the switches 72a to 72e are FETs, the drive unit 73 can output a gate signal to the gates of the FETs to turn the FETs on and off. The voltage acquisition unit 74 acquires the voltage of each of the storage cells 61a to 61e. The storage unit 76 stores a predetermined threshold voltage.

  The control unit 75 specifies the maximum voltage and the minimum voltage from the voltages of the storage cells 61a to 61e acquired by the voltage acquisition unit 74. When the voltage difference between the maximum voltage and the minimum voltage is equal to or greater than the threshold voltage, the control unit 75 turns on the storage cell via a resistor by turning on a switch connected in parallel to the storage cell having the maximum voltage. Discharge. Thereby, the voltage of the said electrical storage cell is lowered | hung and the voltage between electrical storage cells 61a-61e is equalized.

  When there is a power storage cell having a lower SOC than the other power storage cells 61a to 61e, the voltage of this power storage cell is lower than that of the other power storage cells. Due to the operation of the balance circuit 71, the other storage cells are discharged, and the SOC and voltage of the other storage cells are reduced. In this way, the voltages and SOCs of the plurality of power storage cells included in the power storage module 60 are equalized. The balance circuit 71, the drive unit 73, the voltage acquisition unit 74, the control unit 75, and the storage unit 76 correspond to an equalization unit.

  The communication unit 77 has a function of performing serial communication with the battery management device 50, for example. The control unit 75 causes the communication unit 77 to transmit information indicating the voltage of each of the storage cells 61a to 61e acquired by the voltage acquisition unit 74 to the battery management device 50.

  FIG. 5 is a graph schematically showing a time change of the voltage of the storage cell in a state where the balance circuit 71 operates. The horizontal axis indicates the time during which the storage cell is left unpowered, and the vertical axis indicates the voltage of the storage cell. The voltage may be OCV (Open Circuit Voltage). The voltage of a deteriorated storage cell having a fast deterioration progress is indicated by a triangle, and the voltage of a normal storage cell having a deterioration progress rate within an allowable range is indicated by a circle. The voltage of the deteriorated power storage cell decreases more quickly, and a difference occurs from the voltage of the normal power storage cell. Over time, the voltage difference increases and reaches a threshold voltage. In FIG. 5, the time when the voltage difference between the degraded storage cell and the normal storage cell reaches the threshold voltage is indicated by a broken line. In FIG. 5, the time change of the voltage of a normal electrical storage cell in the state where the balance circuit 71 does not operate is indicated by a broken-line circle.

  As shown in FIG. 5, the voltages of the plurality of power storage cells are equalized, so that the voltage of the normal power storage cell is reduced as compared with the case where the balanced circuit 71 does not operate. The voltage difference between and becomes smaller. Even if time elapses, the voltage difference between the degraded storage cell and the normal storage cell is difficult to increase. For this reason, it is expected that it is difficult to detect the deteriorated storage cell based on the time change of the voltage in the state where the balanced circuit 71 operates. On the contrary, in a state where the balanced circuit 71 is not operated, the voltage difference between the deteriorated storage cell and the normal storage cell increases with time. For this reason, it is expected that it is easy to detect the deteriorated energy storage cell based on the time change of the voltage.

  FIG. 6 is a block diagram illustrating a functional configuration example of the battery management device 50 and the management device M according to the first embodiment. The battery management device 50 includes a control unit 51, a first communication unit 52, and a second communication unit 53. The control unit 51 is a processor using a CPU. The first communication unit 52 is connected to a plurality of control boards 70 in the bank 4. The first communication unit 52 receives information transmitted from the control board 70. The second communication unit 53 is connected to the management apparatus M via the communication line 43. The control unit 51 causes the second communication unit 53 to transmit information received from the plurality of control boards 70 to the management device M.

  The management apparatus M is configured using a computer. The management apparatus M includes a control unit 401, a first communication unit 402, and a second communication unit 403. The control unit 401 is a processor using a CPU. The first communication unit 402 is connected to a plurality of battery management devices 50. The first communication unit 402 receives information transmitted from the battery management device 50. The second communication unit 403 is connected to the communication device 1. The control unit 401 causes the second communication unit 403 to transmit information received from the plurality of battery management devices 50 to the communication device 1. The communication device 1 transmits the information received from the management device M to the server device 2. That is, the management apparatus M transmits information to the server apparatus 2 via the communication device 1, and the battery management apparatus 50 transmits information to the server apparatus 2 via the management apparatus M and the communication device 1.

  Next, a deterioration determination method according to this embodiment will be described. The server device 2 functions as a deterioration determination device. The learning model 23 performs machine learning in order to determine the presence / absence of a deteriorated storage cell from the time change of the voltage of the storage cell. For example, the machine learning is executed by the server device 2.

  The voltage is acquired from the state in which the charge states of the plurality of power storage cells connected in series are substantially the same. At this time, in a state where the switch 41 of the bank 4 is opened and the balanced circuit 71 is not operated, the voltage of each storage cell is acquired by the voltage acquisition unit 74, and the acquired voltage is stored in the battery management device 50, the management device M, and It is transmitted via the communication device 1. The battery management device 50 provided in each bank 4 is connected to the management device M via the communication line 43. The time change of the voltage of each of the plurality of power storage cells is stored in, for example, the storage unit 21 of the server device 2.

  FIG. 7 is a graph schematically showing a temporal change in the voltage of the storage cell in a state where voltage equalization is not performed. The horizontal axis indicates the time during which the storage cell is left unpowered, and the vertical axis indicates the voltage of the storage cell. The voltage may be OCV. The voltage of the deteriorated energy storage cell is indicated by a triangle, and the voltage of a normal energy storage cell whose deterioration progress rate is within an allowable range is indicated by a circle. A deteriorated energy storage cell is an energy storage cell whose deterioration progresses faster than a normal energy storage cell. The voltage of the deteriorated power storage cell decreases more quickly, and a difference occurs from the voltage of the normal power storage cell. Unlike the time change of the voltage in the state where the voltage equalization shown in FIG. 5 is performed, the voltage difference between the normal power storage cell and the deteriorated power storage cell continues to increase as time elapses.

  After a certain length of time has elapsed, the voltage difference between the normal storage cell and the deteriorated storage cell is significant, so whether or not the storage cell is a deteriorated storage cell based on the voltage of the storage cell. It is possible to determine. For example, the storage cell may be determined to be a deteriorated storage cell when the voltage after a predetermined time has passed without being energized is less than a predetermined threshold. You may determine with an electrical storage cell being a degradation electrical storage cell, when the ratio with respect to the initial voltage of the voltage after predetermined time passes without energizing is less than a threshold value. The voltage change over time may be approximated by a linear function, and the storage cell may be determined to be a deteriorated storage cell when the absolute value of the voltage change rate with respect to time exceeds a threshold value. Among a plurality of power storage cells, a predetermined number of power storage cells having a lower voltage after a predetermined time has elapsed without being energized may be determined to be deteriorated power storage cells.

  Whether each of the plurality of power storage cells from which the time change in voltage has been acquired is a deteriorated power storage cell may be determined by a person or a computer. For example, according to the server program 2P, the control unit 20 of the server device 2 determines whether each power storage cell is a deteriorated power storage cell based on the time change of each voltage of the plurality of power storage cells stored in the storage unit 21. Determine whether. The determination specifies whether each power storage cell is a deteriorated power storage cell.

  Teacher data is created in which a time change in voltage is associated with a result of specifying whether or not the power storage cell is a deteriorated power storage cell for each of the plurality of power storage cells. The teacher data is stored in the storage unit 21 of the server device 2, for example. Machine learning of the learning model 23 is performed using the created teacher data. For example, the control unit 20 of the server device 2 performs machine learning of the learning model 23 according to the server program 2P. In machine learning, in order to be able to determine whether or not a storage cell is a deteriorated storage cell, it is possible to determine whether or not the storage cell is a deteriorated storage cell in accordance with a time change in the voltage of the storage cell that is unknown whether or not it is a deteriorated storage cell. Perform machine learning to adjust parameters.

  By executing the machine learning process in the server device 2, a learned learning model 23 is obtained. The machine learning may be executed by a computer other than the server device 2. In this case, learning data representing the learning model 23 that has been learned by machine learning is created, and the created learning data is input to the server device 2. The server apparatus 2 obtains a learned learning model 23 by storing learning data in the storage unit 21.

  FIG. 8 is a flowchart illustrating a procedure of processing for determining the presence or absence of a deteriorated power storage element. The control unit 20 of the server device 2 that is a deterioration determination device executes the following processing according to the server program 2P. The target storage element for determining whether or not it is a deteriorated storage element is a storage cell included in the storage system 101. The control unit 20 stops the energization of the power storage module 60 by disconnecting the power storage module 60 including the power storage cell from the power line 42 for energizing the power storage module 60 (S1). For example, the control unit 20 causes the communication unit 22 to transmit a control signal for opening the switch 41 to the switch 41 of the power storage module 60 including the target power storage cell. The control signal is transmitted to the switch 41 via the communication network N, the communication device 1, and the management apparatus M. When the switch 41 is opened, the plurality of power storage modules 60 and the power line 42 are disconnected, and the power storage module 60 is not energized. The bank 4 in which the switch 41 is opened is disconnected from the power line 42 (main circuit). In step S1, a control signal may be transmitted to the battery management device 50, and the battery management device 50 may open the switch 41 according to the control signal. Instead of transmitting a control signal from the server device 2, the switch 41 may be opened independently in the power storage system 101. For example, the switch 41 may be opened manually. The process of step S1 corresponds to an energization stop unit.

  Next, the control unit 20 stops the equalization of the voltages of the plurality of storage cells for the storage module 60 that has been de-energized (S2). For example, the control unit 20 causes the communication unit 22 to transmit a control signal for stopping the operation of the balanced circuit 71 to the control board 70 via the communication network N, the communication device 1, the management device M, and the battery management device 50. Let When the control unit 75 of the control board 70 stops the operation of the balanced circuit 71, the equalization of the voltages of the plurality of power storage cells included in the power storage module 60 is stopped. For example, the operation of the balanced circuit 71 is stopped in all the power storage modules 60 included in the bank 4 in which the switch 41 is opened. The process of step S2 corresponds to an equalization stop unit. Alternatively, step S2 may be performed simultaneously with step S1, or may be performed before step S1.

  Next, the control part 20 acquires the time change of the voltage of the electrical storage cell contained in the electrical storage module 60 in which electricity supply was stopped and operation | movement of the balance circuit 71 stopped (S3). For example, the control unit 20 causes the communication unit 22 to transmit a control signal for acquiring the voltage of the power storage cell to the control board 70 of the power storage module 60 including the target power storage cell. The control signal is transmitted to the control board 70 via the communication network N, the communication device 1, the management device M, and the battery management device 50. In the control board 70, first, the voltages of the power storage cells 61a to 61e are acquired in a state where the charge states of the plurality of power storage cells 61a to 61e included in the power storage module 60 are substantially the same. Subsequently, the voltage acquisition unit 74 repeatedly acquires the voltages of the storage cells 61a to 61e. The voltage acquired by the voltage acquisition unit 74 may be OCV. The control unit 75 causes the communication unit 77 to sequentially transmit information indicating the acquired voltage. Information indicating the voltage is sequentially transmitted to the server device 2 via the battery management device 50, the management device M, the communication device 1, and the communication network N. The server device 2 receives information indicating the voltage of the storage cell by the communication unit 22, and the control unit 20 stores the received information in the storage unit 21. Information indicating the voltage of the storage cell is sequentially received and stored as time passes. Alternatively, information indicating the voltage of the storage cell according to the passage of time may be collectively transmitted and received. In this way, the time change of the voltage of the storage cell is acquired. For example, the time change of voltage is acquired about all the electrical storage cells included in the bank 4 in which the switch 41 is opened. The process in step S3 corresponds to the acquisition unit.

  Next, the control unit 20 reads information indicating the time change of the voltage of the storage cell from the storage unit 21 and provides the information to the learning model 23. The learning model 23 is based on the time change of the voltage of the storage cell. It is determined whether or not is a deteriorated energy storage cell (S4). Since the learning model 23 has already learned the difference in the time change of the voltage between the deteriorated storage cell and the normal storage cell, whether or not the storage cell is a deteriorated storage cell according to the time change of the voltage of the storage cell. Can be determined. The learning model 23 determines whether or not the power storage cell is a deteriorated power storage cell based on the time change of the voltage in a shorter period as compared to the period in which the time change of the voltage of the power storage cell is acquired in order to create the teacher data. May be determined. The process of step S4 corresponds to a determination unit.

  Next, the control unit 20 outputs a determination result as to whether or not the power storage cell is a deteriorated power storage cell (S5). For example, the control unit 20 causes the communication unit 22 to transmit information indicating the determination result to the client device 3 via the communication network N. The client device 3 receives information indicating the determination result by the communication unit 32, and the control unit 30 causes the display unit 33 to display the determination result based on the received information. For example, identification information is assigned to each power storage cell, and the identification information and information indicating whether the power storage cell identified by the identification information is a deteriorated power storage cell are displayed on the display unit 33. The administrator of the power storage system can know which power storage cell is the deteriorated power storage cell by checking the output determination result. Above, the process which determines the presence or absence of a deterioration electrical storage cell (deterioration electrical storage element) is complete | finished.

  After the process for determining the presence / absence of the deteriorated energy storage cell is completed, the energy storage module 60 including the energy storage cell determined to be a deteriorated energy storage cell is removed from the bank 4. For example, the power storage module 60 may be replaced with a new power storage module 60. In bank 4, a plurality of power storage modules 60 other than the removed power storage module 60 may be connected. In the bank 4 to be determined, after the determination process, the switch 41 is closed, and each power storage module 60 enables the operation of the balanced circuit 71 and the operation of the bank 4 can be resumed.

  For some of the banks 4 included in the power storage system 101, the presence / absence of the deteriorated power storage cell is determined, and after the determination of the presence / absence of the deteriorated power storage cell is completed, You may determine the presence or absence of a deterioration electrical storage cell about the bank 4. FIG. The number of banks 4 to be determined at a time may be singular or plural. In this way, by sequentially determining whether or not there is a deteriorated power storage cell for each bank 4, the power storage system 101 is maintained without stopping the operation of the entire power storage system 101, that is, while the operation of the power storage system 101 is continued. Preventive maintenance.

  As described above in detail, in the present embodiment, the energization of the energy storage module 60 is stopped, and the time variation of the voltage of the energy storage cells is acquired in a state where the equalization of the voltages of the plurality of energy storage cells is stopped. Based on the change, it is determined whether or not the power storage cell is a deteriorated power storage cell. Stopping energization of the storage module 60 and stopping of voltage equalization of the storage cell are performed by remote operation (via a communication network). In the state where the equalization of the voltages of the plurality of power storage cells is stopped, the difference in voltage with time is large between the deteriorated power storage cell and the normal power storage cell. For this reason, based on the time change of the voltage of an electrical storage cell, it can be determined whether the electrical storage cell is a degradation electrical storage cell more easily than before, and a degradation electrical storage cell can be detected easily. In addition, since it is possible to easily determine whether or not the storage cell is a deteriorated storage cell, the storage cell having a lower degree of deterioration than the storage cell that has been determined to be a deteriorated storage cell by a conventional method can be used. It can be determined that the cell. Therefore, it is possible to detect the deteriorated power storage cell earlier than before. Since the deteriorated energy storage cell can be detected at an early stage, it becomes possible to remove the deteriorated energy storage cell before the performance of the energy storage system 101 significantly decreases, and it is possible to shorten the time for stopping the bank 4 or the energy storage system 101. .

  In the present embodiment, it is determined by the learning model 23 using supervised learning whether or not the storage cell is a deteriorated storage cell. Whether the power storage cell is a deteriorated power storage cell from the time change of the voltage of the power storage cell by using, as teacher data, the time change of the voltage of the power storage cell and the result of specifying whether or not the power storage cell is a deteriorated power storage cell The learning model 23 for determining whether or not can be learned. By using the learning model 23, it is possible to determine whether or not the power storage cell is a deteriorated power storage cell based on a temporal change in voltage in a short period. For this reason, it is possible to shorten the time during which the bank 4 or the power storage system 101 is stopped in order to determine whether or not the power storage cell is a deteriorated power storage cell.

(Embodiment 2)
In the present embodiment, it is determined whether or not the power storage cell is a deteriorated power storage cell using the operation history of the power storage cell. FIG. 9 is a block diagram illustrating a functional configuration example of the battery management device 50 and the management device M according to the second embodiment. The control board 70 further includes a current acquisition unit 78 and a temperature acquisition unit 79. The current acquisition unit 78 sequentially acquires currents flowing in series in a plurality of power storage cells included in the power storage module 60. The temperature acquisition unit 79 sequentially acquires temperatures at one or a plurality of locations in the power storage module 60 using a temperature sensor. Similarly, the voltage acquisition part 74 acquires the voltage of each electrical storage cell sequentially.

  During the operation of the power storage module 60, the control unit 75 sends information indicating the voltage acquired by the voltage acquisition unit 74, the current acquired by the current acquisition unit 78, and the temperature acquired by the temperature acquisition unit 79 to the communication unit 77. It is made to transmit to the management apparatus 50 sequentially. Information indicating the voltage, current, and temperature is transmitted to the server device 2 via the battery management device 50, the management device M, the communication device 1, and the communication network N. The server device 2 receives information indicating the voltage, current, and temperature at the communication unit 22, and the control unit 20 stores information indicating the voltage, current, and temperature in the storage unit 21. Other configurations of the power storage system 101 and the deterioration determination system 100 are the same as those in the first embodiment.

  The server device 2 sequentially receives and stores information indicating the voltage, current, and temperature of the storage cell as time passes. Information indicating voltage, current, and temperature is stored for each storage cell. In this way, the operation history of the storage cell is acquired.

  For each of the plurality of power storage cells, teacher data is created in which the temporal change in voltage, the operation history, and the result of specifying whether or not the power storage cell is a deteriorated power storage cell are associated with each other. Machine learning of the learning model 23 is performed using the created teacher data. The behavior of the storage cell varies depending on the operation history of the storage cell. For example, when charging and discharging are repeated at a high frequency, the deterioration of the storage cell becomes severe, and the difference between the deteriorated storage cell and the normal storage cell becomes large. In machine learning, it is possible to determine whether or not the storage cell is a deteriorated storage cell according to the time change of the voltage of the storage cell and the operation history whether it is unknown whether or not it is a deteriorated storage cell. Machine learning for adjusting the parameters of the learning model 23 is performed.

  As in the first embodiment, the degradation determination system 100 according to the present embodiment executes a process for determining the presence or absence of a degraded storage cell, as shown in the flowchart of FIG. In step S <b> 4, the control unit 20 reads information indicating the time change of the voltage of the storage cell and information indicating the operation history of the storage cell from the storage unit 21 and provides the information to the learning model 23. The learning model 23 determines whether or not the power storage cell is a deteriorated power storage cell based on the time change of the voltage of the power storage cell and the operation history. Since the learning model 23 has already learned the difference in the time change of the voltage and the operation history between the deteriorated storage cell and the normal storage cell, the storage cell deteriorates in accordance with the time change of the voltage of the storage cell and the operation history. It can be determined whether or not it is a storage cell.

  As described above, in this embodiment, energization of the power storage module 60 is stopped, and the time change of the voltage of the power storage cell is acquired in a state where the equalization of the voltages of the plurality of power storage cells is stopped. Based on the time change of the voltage and the operation history, the learning model 23 determines whether or not the storage cell is a deteriorated storage cell. Although the behavior of the storage cell varies depending on the operation history, the change in the voltage of the storage cell over time, the operation history, and the result of specifying whether the storage cell is a deteriorated storage cell are used as teacher data. The learning model 23 for determining whether or not the storage cell is a deteriorated storage cell can be learned from the time change of the cell voltage and the operation history. By using the learning model 23, it is possible to determine whether or not the power storage cell is a deteriorated power storage cell based on the time change of the voltage and the operation history. It can be easily determined whether or not it is a deteriorated storage cell regardless of the storage cell of the operation history. Therefore, it is possible to easily detect a deteriorated power storage cell from among a large number of power storage cells having different operation histories. Further, similarly to the first embodiment, it is possible to detect a deteriorated storage cell earlier than in the past.

(Embodiment 3)
In the present embodiment, the battery management device 50 functions as a deterioration determination device. FIG. 10 is a block diagram illustrating a functional configuration example of the battery management device 50 according to the third embodiment. The battery management device 50 further includes a learning model 54 and a storage unit 55. The learning model 54 performs the same operation as the learning model 23 in the first or second embodiment. The storage unit 55 is a hard disk or a nonvolatile memory. In the present embodiment, the server device 2 may not include the learning model 23. Other configurations of the power storage system 101 and the deterioration determination system 100 are the same as those in the first or second embodiment.

  The machine learning of the learning model 54 is performed similarly to the machine learning of the learning model 54 in the first or second embodiment. The machine learning may be performed by the battery management device 50. Alternatively, it may be executed on another computer. In this case, learning data representing the learning model 23 learned by machine learning is created, the created learning data is input to the battery management device 50, and the battery management device 50 stores the learning data in the storage unit 55. Thus, a learned learning model 54 is obtained.

  As in the first or second embodiment, the degradation determination system 100 according to the present embodiment executes processing for determining the presence or absence of a degraded storage cell, as shown in the flowchart of FIG. The battery management device 50 executes an operation as a deterioration determination device. The battery management device 50 opens the switch 41 to stop energization of the power storage module 60 (S1), and causes the control board 70 to stop the operation of the balance circuit 71, thereby equalizing the voltages of the plurality of power storage cells. Is stopped (S2). The battery management device 50 receives the information transmitted from the control board 70 by the first communication unit 52 and stores it in the storage unit 55, thereby acquiring the time change of the voltage of the storage cell (S3). The learning model 54 determines whether or not the storage cell is a deteriorated storage cell (S4). Moreover, the battery management apparatus 50 outputs the determination result of whether an electrical storage cell is a deterioration electrical storage cell (S5). For example, the battery management device 50 transmits information indicating the determination result to the client device 3 via the management device M, the communication device 1, and the communication network N. Above, the process which determines the presence or absence of a deterioration electrical storage cell is complete | finished.

  Also in the present embodiment, as in the first or second embodiment, it is possible to easily determine whether or not the power storage cell is a deteriorated power storage cell based on the time change of the voltage of the power storage cell. In addition, the degraded storage cell can be detected earlier than in the past. In the deterioration determination system 100, instead of the battery management device 50, the management device M may function as a deterioration determination device.

  In the first to third embodiments, the presence / absence of a degraded storage cell is determined using a learning model. Alternatively, the deterioration determination system 100 may determine the presence or absence of a deteriorated storage cell without using a learning model. In this form, the deterioration determination device stops the energization of the power storage module 60, acquires the time change of the voltage of the power storage cell in a state where the voltage equalization of the plurality of power storage cells is stopped, and responds to the time change of the voltage. Whether or not the storage cell is a deteriorated storage cell is determined. The stop of energization of the storage module 60 and the stop of voltage equalization of the storage cell are preferably performed by remote operation (via a communication network). In the state where the equalization of the voltages of a plurality of storage cells is stopped, the difference in time change in voltage between the deteriorated storage cell and the normal storage cell is large. Therefore, the presence / absence of the deteriorated storage cell is determined without using the learning model. It is possible.

  In the first to third embodiments, the balance circuit 71 is used to equalize the voltages of a plurality of power storage cells. Alternatively, the control board 70 may perform voltage equalization by a method other than the method using the balanced circuit 71. For example, the control board 70 may perform voltage equalization by discharging a storage cell having a high voltage and charging a storage cell having a low voltage. In the first to third embodiments, the target storage element for determining whether or not it is a deteriorated storage element is a storage cell. Alternatively, the deterioration determination system 100 may use the power storage module 60 as a power storage element to be determined and the bank 4 as a power storage element unit. In the first to third embodiments, the power storage system 101 includes a plurality of banks 4. Alternatively, the power storage system 101 may be composed of a single bank 4.

  As described above, the deterioration determination method stops energization of a power storage element unit including a plurality of power storage elements, stops equalization of voltages of the plurality of power storage elements, and performs time change of voltages of the plurality of power storage elements. Based on the acquired time change of the voltage, the presence / absence of a deterioration power storage element whose deterioration progresses quickly is determined. The deterioration determination method may be implemented by a computer program. The computer program includes a process for stopping energization of a power storage element unit including a plurality of power storage elements, a process for stopping equalization of voltages of the plurality of power storage elements, and a time change in the voltages of the plurality of power storage elements. And a process of determining the presence or absence of a deteriorated power storage element that progresses rapidly based on the time change of the acquired voltage.

  In the deterioration determination method, whether or not the plurality of power storage elements is a deterioration power storage element based on a temporal change in voltage in a state where current is not supplied and voltage equalization is stopped by a learning model using supervised learning. Determine whether or not. This deterioration determination method may be implemented by a computer program.

  In the deterioration determination method, the change over time of the voltage of the power storage element in a state in which energization is not performed and voltage equalization is not performed, and the result of specifying whether or not the power storage element is a deteriorated power storage element are used as teacher data. Then, machine learning of the learning model is performed. This deterioration determination method may be implemented by a computer program.

  In the deterioration determination method, the operation history of the plurality of power storage elements is obtained, and the learning model using supervised learning is used to determine the voltage of the plurality of power storage elements in a state where current is not supplied and voltage equalization is stopped. Based on the time change and the operation history, it is determined whether or not the battery is a deteriorated power storage element. This deterioration determination method may be implemented by a computer program.

  In the deterioration determination method, the temporal change of the voltage of the power storage element in a state where current is not supplied and voltage equalization is not performed, the operation history of the power storage element, and whether or not the power storage element is a deteriorated power storage element. Machine learning of the learning model is performed using the identified result as teacher data. This deterioration determination method may be implemented by a computer program.

  In the deterioration determination method, the presence / absence of a deteriorated storage element is determined for a part of a plurality of storage element units connected in parallel, and the presence / absence of a deteriorated storage element is determined for the part of the storage element units. Is completed, the presence or absence of the degraded storage element is determined for the other storage element unit among the plurality of storage element units. This deterioration determination method may be implemented by a computer program.

  A degradation determination device that determines the presence or absence of a degraded storage element that rapidly progresses degradation stops an energization stop unit that stops energization of a storage element unit that includes a plurality of storage elements, and stops voltage equalization of the plurality of storage elements An equalization stop unit and the energization stop unit stop energization of the power storage element unit, and the equalization stop unit stops voltage equalization, and obtains time changes in voltages of the plurality of power storage elements. An acquisition unit and a determination unit that determines the presence or absence of a deteriorated power storage element based on a change in the acquired voltage over time. The deterioration determination device may be implemented by the battery management device 50 or the control board 70 provided in the vicinity of a power storage element unit such as the power storage system 101. The deterioration determination device may be implemented by the battery management device 50 and the control board 70. The deterioration determination device may be implemented using the server device 2 connected to the power storage element unit through a communication network.

  In the deterioration determination device, the determination unit uses a learning model that uses supervised learning to determine whether the plurality of power storage elements are deteriorated based on a time change in voltage in a state where energization is stopped and voltage equalization is stopped. It is determined whether it is a power storage element.

  The degradation determination system includes a storage element unit including a plurality of storage elements, a switch for connecting and disconnecting an electric wire for energizing the storage element unit, and a voltage of the plurality of storage elements. An equalization unit that equalizes and a deterioration determination device that determines the presence or absence of a deteriorated power storage element that progresses rapidly are provided. The degradation determination device includes an equalization stop unit that stops the operation of the equalization unit, the switch disconnects the storage element unit from the electric wire, and the equalization stop unit stops the operation of the equalization unit. In this state, an acquisition unit that acquires temporal changes in the voltages of the plurality of power storage elements, and a determination unit that determines presence / absence of a deteriorated electrical storage element based on the acquired temporal changes in voltage.

  According to the above configuration, in a state where the energization of the power storage element unit including the plurality of power storage elements is stopped and the equalization of the voltages of the plurality of power storage elements is stopped, the time change of the voltage of the power storage elements is acquired, and the time of the voltage Based on the change, it is determined whether or not the power storage element is a deteriorated power storage element whose progress of deterioration is fast. In the state where the equalization of the voltages of the plurality of power storage elements is stopped, the difference in voltage with time is large between the deteriorated power storage element and the normal power storage element. For this reason, based on the time change of the voltage of an electrical storage element, it can be easily determined whether an electrical storage element is a degradation electrical storage cell.

  According to the above configuration, whether or not the power storage element is a deteriorated power storage element is determined by a learning model using supervised learning. Whether the power storage element is a deteriorated power storage element from the time change of the voltage of the power storage element by using, as teacher data, the time change of the voltage of the power storage element and the result of specifying whether or not the power storage element is a deteriorated power storage element It is possible to learn a learning model that can determine whether or not. By using the learning model, it is possible to determine whether or not the power storage element is a deteriorated power storage element based on the time change of the voltage in a short period.

  According to the above configuration, whether or not the power storage element is a deteriorated power storage element is determined by the learning model based on the time change of the voltage of the power storage element and the operation history. Although the behavior of the power storage element varies depending on the operation history, the storage element is obtained by using the time change of the voltage of the power storage element, the operation history, and the result of specifying whether or not the power storage element is a deteriorated power storage element as teacher data. A learning model that can determine whether or not the power storage element is a deteriorated power storage element can be learned from the time change of the voltage and the operation history. By using the learning model, it is possible to easily determine whether or not the power storage element is a deteriorated power storage element regardless of the operation history.

  According to the above configuration, when there are a plurality of power storage element units, it is determined whether or not there are deteriorated power storage elements for some of the power storage element units, and after the determination is completed, the presence or absence of the deteriorated power storage elements for other power storage element units. Judgment is made. In a system including a plurality of power storage element units, preventive maintenance can be performed while continuing operation of the system.

  The present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Degradation determination system 101 Power storage system 2 Server device 20 Control unit 21 Storage unit 23 Learning model 4 Bank 41 Switch 50 Battery management device 60 Power storage module 61a, 61b, 61c, 61d, 61e Power storage cell 70 Control board 71 Balance circuit 74 Voltage Acquisition unit 78 Current acquisition unit 79 Temperature acquisition unit

Claims (9)

Stop energization of a storage element unit including a plurality of storage elements,
Stopping equalization of voltages of the plurality of power storage elements,
Obtaining a time change in voltage of the plurality of power storage elements;
Based on the time change of the acquired voltage, determine the presence or absence of a deterioration storage element that progresses quickly.
Degradation judgment method. Whether or not the plurality of power storage elements are deteriorated power storage elements is determined by a learning model using supervised learning based on a temporal change in voltage in a state where energization is not performed and voltage equalization is stopped. The deterioration determination method according to claim 1. The time variation of the voltage of the power storage element in a state where current is not supplied and voltage equalization is not performed, and the result of specifying whether or not the power storage element is a deteriorated power storage element are used as teacher data. The deterioration determination method according to claim 2, wherein machine learning is performed. Obtaining an operation history of the plurality of power storage elements;
Whether or not the plurality of power storage elements are deteriorated power storage elements based on the time change of the voltage and the operation history in a state where voltage equalization is stopped with the learning model using supervised learning. The deterioration determination method according to claim 1. A time change of the voltage of the power storage element in a state where current is not supplied and voltage equalization is not performed, an operation history of the power storage element, and a result of specifying whether or not the power storage element is a deteriorated power storage element. The deterioration determination method according to claim 4, wherein machine learning of the learning model is performed as teacher data. For some of the storage element units among the plurality of storage element units connected in parallel, determine the presence or absence of a deteriorated storage element,
6. After the determination of the presence / absence of deteriorated energy storage elements for the part of the energy storage element units is completed, the presence / absence of deteriorated energy storage elements is determined for other energy storage element units in the plurality of energy storage element units. The deterioration determination method according to any one of the above. In a deterioration determination device that determines the presence or absence of a deterioration power storage element whose deterioration progresses quickly,
An energization stop unit for stopping energization of an energy storage element unit including a plurality of energy storage elements;
An equalization stop unit for stopping equalization of voltages of the plurality of power storage elements;
An acquisition unit that acquires time changes in voltages of the plurality of power storage elements in a state where the power supply stop unit stops energization of the power storage element unit and the equalization stop unit stops voltage equalization;
A degradation determination device comprising: a determination unit configured to determine the presence or absence of a degradation power storage element based on a time change of the acquired voltage. Whether the determination unit is a degraded storage element based on a temporal change in voltage in a state where energization is stopped and voltage equalization is stopped for the plurality of storage elements by a learning model using supervised learning. The deterioration determination apparatus according to claim 7, wherein a determination is made whether or not. A power storage element unit including a plurality of power storage elements;
A switch for connecting and disconnecting an electric wire for energizing the electric storage element unit to and from the electric storage element unit;
An equalizing unit for equalizing voltages of the plurality of power storage elements;
A deterioration determination device that determines the presence or absence of a deterioration power storage element that progresses rapidly;
The degradation determination device
An equalization stop unit for stopping the operation of the equalization unit;
An acquisition unit that acquires time changes in voltages of the plurality of power storage elements in a state where the switch disconnects the power storage element unit from the electric wire and the equalization stop unit stops the operation of the equalization unit;
A degradation determination system comprising: a determination unit that determines presence / absence of a deterioration power storage element based on a time change of the acquired voltage.

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