Operation management system for energy storage devices, operation management device, and operation management method

Abstract

To provide an operation management system, operation management device and operation management method for a power storage device.SOLUTION: An operation management system includes a control device for executing control related to a power storage device, and an operation management device for the power storage device that is communicably connected to the control device. The control device includes a storage unit for storing control parameters, and a control unit for executing the control based on the control parameters stored in the storage unit. The operation management device includes a detection unit for detecting the state of the power storage device, a derivation unit for deriving a control parameter to be set by the control device according to a detection result by the detection unit, and a transmission unit for transmitting the control parameter derived by the derivation unit to the control device. The control device includes an update unit for updating the control parameters stored in the storage unit based on the control parameter received from the operation management device.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an operation management system, an operation management device, and an operation management method for an energy storage device. [Background technology]

[0002] Energy storage devices are used in conjunction with control devices that control the charging and discharging state of the energy storage device, its temperature, and the ambient temperature in the installation environment (see, for example, Patent Document 1).

[0003] The control parameters used in such control devices are generally designed based on the initial state of the energy storage device and are pre-written into the control device's internal memory. These control parameters are often designed based on assumptions at the time of product delivery. The control device reads the control parameters written to memory as needed and controls the charge / discharge state of the energy storage device, its temperature, and the ambient temperature of the installation environment. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-071100 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, control parameters set based on the initial state of the energy storage device may deviate from appropriate values ​​due to aging degradation of the energy storage device or special circumstances that could not be predicted during the design phase.

[0006] This invention has been made in view of the above circumstances, and aims to provide an operation management system, an operation management device, and an operation management method for an energy storage device that can redesign the control parameters in the control device according to the state of the energy storage device. [Means for solving the problem]

[0007] The operation management system includes a control device that executes control related to a power storage device, and an operation management device of the power storage device communicably connected to the control device. The control device includes a storage unit that stores control parameters, and a control unit that executes the control based on the control parameters stored in the storage unit. The operation management device includes a detection unit that detects the state of the power storage device, a derivation unit that derives control parameters to be set in the control device according to the detection result by the detection unit, and a transmission unit that transmits the control parameters derived by the derivation unit to the control device. The control device includes an update unit that updates the control parameters stored in the storage unit based on the control parameters received from the operation management device.

[0008] The operation management device includes a detection unit that detects the state of the power storage device, a derivation unit that derives control parameters to be set in a control device that executes control related to the power storage device according to the detection result by the detection unit, and a transmission unit that transmits the control parameters derived by the derivation unit to the control device in order to update the control parameters used for the control.

[0009] The operation management method detects the state of the power storage device, derives control parameters to be set in a control device that executes control related to the power storage device according to the detection result of the state, and transmits the derived control parameters to the control device in order to update the control parameters used for the control.

Advantages of the Invention

[0010] According to the present application, the control parameters in the control device can be redesigned according to the state of the power storage device.

Brief Description of the Drawings

[0011] [Figure 1] It is a schematic diagram for explaining the overall configuration of the operation management system in Embodiment 1. [Figure 2]This is a block diagram illustrating the internal configuration of the control device. [Figure 3] This is a block diagram illustrating the internal configuration of the operation management device. [Figure 4] This graph shows the relationship between terminal voltage and discharge capacity. [Figure 5] This graph shows the concentration distribution of lithium ions inside the battery. [Figure 6] This graph shows the relationship between terminal voltage and discharge capacity after updating the control parameters. [Figure 7] This graph shows the lithium ion concentration distribution inside the battery after updating the control parameters. [Figure 8] This is a flowchart illustrating the procedures performed by the operation management device. [Figure 9] This is a flowchart illustrating the steps of the process performed by the control device. [Figure 10] This is a schematic diagram illustrating the overall configuration of the operation management system in Embodiment 2. [Figure 11] This is a block diagram illustrating the internal configuration of the control device. [Figure 12] This is a schematic diagram illustrating the overall configuration of the operation management system in Embodiment 3. [Figure 13] This is a block diagram illustrating the internal configuration of the control device. [Figure 14] This graph shows the temperature changes of an energy storage device. [Modes for carrying out the invention]

[0012] Conventionally, control devices that perform control over energy storage devices store pre-set control parameters. The control device reads the pre-stored control parameters as needed and performs control operations based on the read parameters to control the charge / discharge state of the energy storage device, its temperature, and the ambient temperature in the set environment.

[0013] Control parameters designed based on the initial state of the energy storage device may deviate from appropriate values ​​due to device degradation or unforeseen circumstances that could not be predicted during the design phase. If the control device performs the above control using control parameters that deviate from appropriate values, the energy storage device may not be able to perform as required. In contrast, the operation management system for a power storage device comprises a control device that performs control relating to the power storage device, and an operation management device for the power storage device that is communicably connected to the control device, wherein the control device comprises a storage unit that stores control parameters, and a control unit that performs the control based on the control parameters stored in the storage unit, wherein the operation management device comprises a detection unit that detects the state of the power storage device, a derivation unit that derives control parameters to be set by the control device according to the detection result by the detection unit, and a transmission unit that transmits the control parameters derived by the derivation unit to the control device, wherein the control device comprises an update unit that updates the control parameters stored in the storage unit based on the control parameters received from the operation management device. The operation management device automatically derives the control parameters that should be set in the control device based on the current state of the energy storage device and transmits them to the control device. The control device updates the control parameters based on the control parameters received from the operation management device. Therefore, even if the state of the energy storage device changes, the control parameters can be updated at any time to suit the changed state.

[0014] The derivation unit may identify a mathematical model representing the characteristics of the energy storage device based on the detection results from the detection unit, and derive control parameters to be set in the control device in accordance with the identified mathematical model. With this configuration, even if the state of the energy storage device changes, the operation management device can derive control parameters based on a mathematical model representing the characteristics of the energy storage device after the change.

[0015] The derivation unit may periodically derive control parameters to be set in the control device. With this configuration, the control parameters are updated periodically.

[0016] The derivation unit may calculate the amount of change in state detected by the detection unit, and if the calculated amount of change is greater than a threshold, it may derive control parameters that should be set in the control device. With this configuration, the control parameters are updated when there is a large change in the state of the energy storage device.

[0017] The control may also be the charging and discharging control of the energy storage device. With this configuration, the control parameters related to the charging and discharging control of the energy storage device can be updated as appropriate.

[0018] The control may also be the control of an air conditioner that provides air conditioning for the installation environment of the energy storage device. With this configuration, the control parameters of the air conditioner that adjust the temperature, airflow direction, airflow rate, etc., in the installation environment of the energy storage device can be updated.

[0019] The control may also be temperature control of the energy storage device. With this configuration, the control parameters of the cooling device that controls the temperature of the energy storage device can be updated.

[0020] The operation management device for the energy storage device includes a detection unit that detects the status of the energy storage device, a derivation unit that derives control parameters to be set in a control device that performs control of the energy storage device according to the detection result by the detection unit, and a transmission unit that transmits the control parameters derived by the derivation unit to the control device in order to update the control parameters used for the control. Therefore, even if the state of the energy storage device changes, the control parameters can be updated in real time to match the changed state.

[0021] The method for operating and managing an energy storage device involves detecting the state of the energy storage device, deriving control parameters to be set in a control device that performs control related to the energy storage device according to the detection result of the state, and transmitting the derived control parameters to the control device in order to update the control parameters used for the control. Therefore, even if the state of the energy storage device changes, the control parameters can be updated in real time to match the changed state.

[0022] The present invention will be described in detail below with reference to the drawings illustrating its embodiments. (Embodiment 1) Figure 1 is a schematic diagram illustrating the overall configuration of the operation management system in Embodiment 1. The operation management system in Embodiment 1 comprises a power storage device 100, a control device 210 that performs control related to the power storage device 100, and an operation management device 300 that manages the operation of the power storage device 100.

[0023] The energy storage device 100 includes rechargeable energy storage elements (cells) such as lithium-ion batteries, solid-state batteries, polymer batteries, and lead-acid batteries, but excludes electronic components such as capacitors. In other words, the energy storage device 100 includes secondary batteries that undergo dynamic and time-series changes during charging and discharging, but excludes electronic components such as capacitors that complete charging and discharging operations instantaneously using only the electric double layer. The energy storage device 100 may also include modules in which multiple cells are connected in series, banks in which multiple modules are connected in series, domains in which multiple banks are connected in parallel, etc.

[0024] The control device 210 measures the state of the energy storage device 100 and performs control related to the energy storage device 100 based on the measurement results. The state of the energy storage device 100 measured by the control device 210 is, for example, the terminal voltage of the energy storage device 100. Alternatively, it may be the current flowing through the energy storage device 100, the temperature of the energy storage device 100, or the ambient temperature of the environment in which the energy storage device 100 is installed. The control performed by the control device 210 is, for example, charge and discharge control of the energy storage device 100. Alternatively, it may be temperature control of the energy storage device 100, control of the air conditioner, etc.

[0025] In the following Embodiment 1, one of the control methods for the energy storage device 100 will be described, specifically the charging and discharging control of the energy storage device 100 by the control device 210.

[0026] The control device 210 has pre-designed control parameters for performing charge and discharge control of the energy storage device 100. The control parameters are stored in the storage unit 212 of the control device 210 (see Figure 2). An example of a control parameter is the lower limit of the terminal voltage (lower voltage limit) in the energy storage device 100. Alternatively, it may include the upper limit of the terminal voltage (upper voltage limit), the waiting time after charging, the current value of the discharge current, etc. These control parameters are designed during the manufacturing or installation of the energy storage device 100 and are stored in the storage unit 212 of the control device 210, which is installed together with the energy storage device 100.

[0027] When the control device 210 performs charge and discharge control of the energy storage device 100, it reads the control parameters stored in the memory unit 212 and performs charge and discharge control based on the read control parameters. As charge and discharge control based on control parameters, the control device 210 may, for example, perform charge and discharge control that limits the fluctuation range of the SOC so that the terminal voltage of the energy storage device 100 does not fall below a lower limit. Here, SOC is an abbreviation for State of Charge, where a fully charged state is represented as 100% and a completely discharged state as 0%. Limiting the fluctuation range means, for example, applying charge and discharge control that uses the battery only within the range of 10% ≤ SOC ≤ 85%.

[0028] The operation management device 300 is connected to the control device 210 via a communication network N and manages the operation of the energy storage device 100 from a remote location. Specifically, the operation management device 300 remotely monitors the status of the energy storage device 100 and, according to the status of the energy storage device 100, derives new control parameters to be used in the charge / discharge control by the control device 210 and remotely updates the control parameters stored in the memory unit 212 of the control device 210. Here, "remote location" refers to a location far from the energy storage device 100 and the control device 210, and may be overseas or in outer space. The remote location does not necessarily have to be a geographically distant location, and may include a location that is too far away to directly operate the energy storage device 100 and the control device 210.

[0029] The operation management device 300 acquires the measured values ​​measured by the control device 210 via communication through the communication network N in order to remotely monitor the status of the energy storage device 100. The communication network N may be an internal intranet network of a company, a domestic general line, an international line, or even outer space. Based on the measured values, the operation management device 300 derives new control parameters to be used in charge / discharge control according to the status of the energy storage device 100 detected. The operation management device 300 transmits the newly derived control parameters to the control device 210 via the communication network N.

[0030] The control device 210 updates the control parameters stored in the memory unit 212 based on the control parameters received from the operation management device 300. The control device 210 then performs charge and discharge control using the updated control parameters. As a result, even when the energy storage device 100 is in a degraded state, the control device 210 can use control parameters appropriate to the degraded state, thereby achieving more favorable charge and discharge control.

[0031] In the example in Figure 1, the energy storage device 100 and the control device 210 are described as separate, independent devices. Alternatively, the control device 210 may be mounted on the energy storage device 100 and integrated with it. Furthermore, the control device 210 and the operation management device 300 may be integrated. Moreover, the energy storage device 100, the control device 210, and the operation management device 300 may all be integrated.

[0032] Figure 2 is a block diagram illustrating the internal configuration of the control device 210. In Embodiment 1, the control device 210 is, for example, a BMU (Battery Management Unit) and comprises a control unit 211, a storage unit 212, a measurement unit 213, an output unit 214, and a communication unit 215. Alternatively, the control device 210 may be a BMS (Battery Management System) or a general-purpose computer.

[0033] The control unit 211 is composed of a microcontroller or the like. Based on the control program stored in the built-in memory and the data stored in the memory unit 212, the control unit 211 performs various calculations and controls the operation of each hardware component, making the entire device function as a control device 210.

[0034] The memory unit 212 is equipped with memory such as EEPROM (Electronically Erasable Programmable Read Only Memory). Various data and programs are stored in the memory unit 212. The data stored in the memory unit 212 includes control parameters related to charge and discharge control that are designed during the manufacturing or installation of the energy storage device 100. The control unit 211 reads the data and programs stored in the memory unit 212 as appropriate and rewrites them as necessary. For example, when the control unit 211 receives control parameters derived from the operation management device 300 from the communication unit 215, it updates the control parameters by rewriting the control parameters stored in the memory unit 212 with the derived control parameters.

[0035] The measurement unit 213 measures the terminal voltage of the energy storage device 100, the current flowing through the energy storage device 100, the temperature of the energy storage device 100, the ambient temperature of the energy storage device 100, and so on. The measurement targets of the measurement unit 213 are appropriately selected according to the calculations and controls performed by the control device 210. For example, in charge / discharge control, if the lower or upper limit of the terminal voltage is to be limited, the terminal voltage of the energy storage device 100 is measured. The measurement unit 213 may be equipped with a voltage sensor to measure the terminal voltage of the energy storage device 100, a current sensor to measure the current flowing through the energy storage device, a temperature sensor to measure the temperature of the energy storage device 100, a temperature sensor to measure the ambient temperature, etc., in order to measure the above values. Alternatively, the measurement unit 213 may acquire the above values ​​using sensors provided outside the control device 210.

[0036] The output unit 214 outputs control signals to turn on or off switches, such as switches that connect or disconnect the charging path from the power supply (not shown) to the energy storage device 100, and switches that connect or disconnect the discharge path from the energy storage device 100 to the load (not shown), based on instructions from the control unit 211. Such switches can be semiconductor elements such as FETs (Field Effect Transistors) or relays. The control unit 211 controls the charging and discharging of the energy storage device 100 by controlling the on / off state of the switches provided in the charging and discharging paths of the energy storage device 100.

[0037] The communication unit 215 is equipped with a communication interface for communicating with the operation management device 300 via the communication network N. The communication unit 215 outputs data received from the operation management device 300 via the communication network N to the control unit 211, and when data to be sent to the operation management device 300 is input from the control unit 211, it transmits the input data to the operation management device 300.

[0038] Figure 3 is a block diagram illustrating the internal configuration of the operation management device 300. The operation management device 300 comprises a control unit 301, a storage unit 302, a communication unit 303, an operation unit 304, and a display unit 305.

[0039] The control unit 301 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and the like. The CPU in the control unit 301 loads various computer programs stored in the ROM or memory unit 302 onto the RAM and executes them, thereby enabling the entire device to function as an operation management device 300.

[0040] The control unit 301 is not limited to the above configuration and may be any processing circuit or arithmetic circuit equipped with multiple CPUs, multi-core CPUs, GPUs (Graphics Processing Units), microcontrollers, volatile or non-volatile memory, etc. Furthermore, the control unit 301 may be equipped with functions such as a timer for measuring the elapsed time from the time a measurement start instruction is given until a measurement end instruction is given, a counter for counting numbers, and a clock for outputting date and time information.

[0041] The storage unit 302 is equipped with a storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive). The storage unit 302 stores various computer programs executed by the control unit 301, as well as data necessary for the execution of these computer programs. The computer programs stored in the storage unit 302 include a simulation program that simulates the behavior of the energy storage device 100. The simulation program is, for example, an executable binary. The theoretical formulas that form the basis of the simulation program are described by algebraic equations or differential equations that represent the behavior of the energy storage device 100.

[0042] Furthermore, the memory unit 302 may store mathematical models obtained as a result of the simulation. The mathematical model may be, for example, executable code executed by a programming language or numerical analysis software. Alternatively, the mathematical model may be definition information or library files referenced by the programming language or numerical analysis software.

[0043] The program stored in the storage unit 302 may be provided by a non-temporary recording medium on which the program is recorded in a readable format. The recording medium is, for example, a portable memory such as a CD-ROM, USB (Universal Serial Bus) memory, SD (Secure Digital) card, microSD card, or CompactFlash®. In this case, the control unit 301 reads the program from the recording medium using a reading device (not shown) and installs the read program into the storage unit 302. The program stored in the storage unit 302 may also be provided by communication via the communication unit 303. In this case, the control unit 301 obtains the program through the communication unit 303 and installs the obtained program into the storage unit 302.

[0044] The communication unit 303 is equipped with an interface for communicating with the control device 210 via the communication network N. The communication unit 303 outputs data received from the control device 210 via the communication network N to the control unit 301, and when data to be sent to the control device 210 is input from the control unit 301, the communication unit 303 transmits the input data to the control device 210.

[0045] The operation unit 304 is equipped with an input interface such as a keyboard and mouse, and accepts operations from administrators, etc. The display unit 305 is equipped with a liquid crystal display device, etc., and displays information that should be notified to administrators, etc. In this embodiment, the operation management device 300 is configured to include the operation unit 304 and the display unit 305, but the operation unit 304 and the display unit 305 are not essential, and the operation management device 300 may be configured to accept operations through a computer connected to the outside of the operation management device 300 and output the information to be notified to the external computer.

[0046] Below, we will use a lithium-ion battery as an example of the energy storage device 100 and explain an example of a state change that occurs in the energy storage device 100 (lithium-ion battery).

[0047] Figure 4 is a graph showing the relationship between terminal voltage and discharge capacity. In the graph shown in Figure 4, the vertical axis represents the terminal voltage (V) of the lithium-ion battery, and the horizontal axis represents the discharge capacity (Ah). The relationship between terminal voltage and discharge capacity shown in Figure 4 was obtained through actual measurements.

[0048] The graph shown as a solid line in Figure 4 represents the discharge characteristics of a lithium-ion battery in its initial manufacturing state. The terminal voltage of a lithium-ion battery gradually decreases from a fully charged state during discharge, and then drops sharply at the end of discharge. If a lower limit (lower voltage limit) is set as a control parameter for charge / discharge control, the control device 210 stops discharge when the terminal voltage reaches the lower limit. Therefore, the terminal voltage of the lithium-ion battery is the lower voltage V shown in Figure 4. L0 It will decrease to that point.

[0049] Lithium-ion batteries degrade with repeated charging and discharging. The dashed line in Figure 4 shows the discharge characteristics of a degraded lithium-ion battery. Even when degraded, the terminal voltage of a lithium-ion battery gradually decreases from the fully charged state during discharge, similar to a lithium-ion battery in its initial manufacturing state, and drops sharply at the end of discharge. The terminal voltage of a degraded lithium-ion battery reaches a lower voltage limit V at a lower discharge capacity. L0 It reaches.

[0050] The decrease in discharge capacity is likely due to a decrease in lithium ion diffusion in the separator. In this case, the internal resistance of the battery increases due to increased ohmic losses in the ion conductor, and variations in lithium ion concentration become more pronounced within the porous electrode of the positive electrode.

[0051] Figure 5 is a graph showing the lithium ion concentration distribution inside the battery. The graph in Figure 5 represents the change in lithium ion concentration from the negative electrode to the positive electrode during the final stage of discharge of a lithium-ion battery. The vertical axis of the graph in Figure 5 shows the simulated lithium ion concentration (mol / L), and the horizontal axis shows the distance from the negative electrode current collector foil (μm). n,minis the position of the interface between the negative electrode current collector foil and the negative electrode (i.e., the origin on the X axis), x n,max x is the position of the interface between the negative electrode and the separator (distance from the negative electrode current collector foil to the separator), x p,min x is the position of the interface between the separator and the positive electrode (distance from the negative electrode current collector foil to the positive electrode), x p,max This represents the position of the interface between the positive electrode and the positive electrode current collector foil (the distance from the negative electrode current collector foil to the positive electrode current collector foil).

[0052] The graph shown as a solid line in Figure 5 represents the change in lithium ion concentration in a lithium-ion battery in its initial manufacturing state. In the initial manufacturing state, the lithium ion concentration on the negative electrode side is slightly higher, and the lithium ion concentration on the positive electrode side is slightly lower, but overall it is approximately constant. This indicates that a uniform reaction is occurring inside the positive electrode. This is a desirable lithium ion concentration distribution.

[0053] The dashed line in Figure 5 shows the change in lithium ion concentration in a degraded lithium-ion battery. In a degraded state, the lithium ion concentration gradually decreases from the negative electrode current collector foil to the positive electrode, and then decreases even more sharply within the positive electrode.

[0054] If there is a large variation in lithium ion concentration in the thickness direction of the porous electrode (i.e., a large variation in the reaction distribution), then there will also be a large variation in the amount of active material absorbed and released by the active particles. In other words, within the porous electrode, there will be areas where a large amount of active material enters and exits, and areas where a small amount of active material enters and exits, all at the same time.

[0055] Therefore, the operation management device 300 finds a lithium-ion diffusion coefficient that fits the charge-discharge curve through simulation trials. The operation management device 300 performs simulations using mathematical models that express the phenomena inside the lithium-ion battery using mathematical formulas, etc.

[0056] In the operation management device 300, a so-called Newman model is used as an example of a mathematical model. The Newman model includes the Nernst-Planck equation for solving ion migration and ion diffusion in electrolytes and porous electrodes. The Nernst-Planck equation is represented by the following formula.

[0057] [Number]

[0058] Here, σl is the liquid-phase conductivity (S / m), φ l is the liquid-phase potential (V), R is the gas constant (J / (K·mol)), T is the temperature (K), F is the Faraday constant (C / mol), f is the activity coefficient, c l is the lithium-ion concentration (mol / m 3 ), t + is the cation transference number, i tot is the reaction current density (A / m 3 ). D l is the diffusion coefficient of lithium ions in the electrolyte (m 2 / s).

[0059] The operation management device 300 sets the diffusion coefficient of lithium ions after degradation to α×D l (α is a real number satisfying 0 < α < 1), and sequentially changes the value of α such as 0.05, 0.10,..., 0.95, and executes a plurality of simulations based on the above Newman model. The operation management device 300 adopts, as the diffusion coefficient of lithium ions after degradation, the value closest to the measurement data as a result of the simulation.

[0060] Next, the operation management device 300 executes a simulation while changing the lower limit value (lower limit voltage) with respect to the terminal voltage, and finds the conditions under which the distribution of lithium-ion concentration at the end of discharge inside the positive electrode is improved.

[0061] The increase width ΔV L of the lower limit voltage is represented by ΔV L = V L1 - V L0 . Here, V L0This is the lower limit voltage before the change, V L1 This is the lower limit voltage after the change. Lower limit voltage V L1 This is a value derived by the operation management device 300 as one of the control parameters that should be set in the control device 210.

[0062] The variation in lithium ion concentration at the positive electrode is evaluated by the following equation 2.

[0063]

number

[0064] Here, x p,min x represents the distance from the negative electrode current collector foil to the positive electrode, p,max x represents the distance from the negative electrode current collector foil to the positive electrode current collector foil. p,min and x p,max It has the dimension of length (μm).

[0065] Here, c Li+ This represents the concentration of lithium ions at the positive electrode, and c Li+ The bar represents the average concentration of lithium ions at the positive electrode. Average concentration of lithium ions at the positive electrode c Li+ A bar is represented by the following number 3.

[0066]

number

[0067] W is zero when the lithium ion concentration within the positive electrode is uniform, and becomes larger as the concentration becomes more non-uniform.

[0068] From the above equation, ΔV L It can be seen that the desired control can be obtained by decreasing W while decreasing . Therefore, the operation management device 300 uses appropriate weights p, q (where p and q are positive real numbers) to calculate p × (ΔV L ) 2 ΔV that minimizes +q × W LBy finding this, the control parameters for the control device 210 can be derived.

[0069] In the example above, the control parameters are derived by focusing on the diffusion coefficient of lithium ions at the end of discharge. Alternatively, the operation management device 300 may derive the control parameters by focusing on the diffusion coefficient of lithium ions at the end of charge.

[0070] Figure 6 is a graph showing the relationship between terminal voltage and discharge capacity after updating the control parameters. In the graph shown in Figure 6, the vertical axis represents the terminal voltage (V) of the lithium-ion battery, and the horizontal axis represents the discharge capacity (Ah). The relationship between terminal voltage and discharge capacity shown in Figure 6 was obtained by actual measurement. Figure 6 also shows the relationship between terminal voltage and discharge voltage in the initial state and the degraded state for reference.

[0071] The graph in Figure 6 shows that by increasing the lower limit voltage (control parameter), the decrease in discharge capacity can be suppressed, and charge / discharge control close to the initial state can be performed.

[0072] Figure 7 is a graph showing the lithium ion concentration distribution inside the battery after updating the control parameters. The graph in Figure 7 shows the change in lithium ion concentration from the negative electrode to the positive electrode during the final stage of discharge of the lithium-ion battery. In the graph shown in Figure 7, the vertical axis represents the simulated value of lithium ion concentration (mol / L), and the horizontal axis represents the distance from the negative electrode current collector foil (μm). Figure 7 also shows the lithium ion concentration distribution in the initial state and the degraded state for reference.

[0073] The graph in Figure 7 shows that by increasing the lower voltage limit (control parameter), variations in lithium ion concentration inside the positive electrode can be suppressed, enabling charge / discharge control closer to the initial state.

[0074] Figure 8 is a flowchart illustrating the procedure for processing performed by the operation management device 300. The control unit 301 of the operation management device 300 performs the following processing at regular intervals or at intervals instructed by the administrator, etc. The control unit 301 acquires measured values ​​related to the energy storage device 100 (step S101). An example of measured values ​​related to the energy storage device 100 is the terminal voltage of the energy storage device 100. The control unit 301 may directly measure the terminal voltage of the energy storage device 100 using a voltage sensor or the like, or it may acquire the measured values ​​measured by the control device 210 via communication.

[0075] Next, the control unit 301 determines whether or not to update the control parameters (step S102). The control unit 301 may decide to update the control parameters at, for example, regular intervals, predetermined intervals, or intervals instructed by an administrator. Alternatively, the control unit 301 may decide whether or not to update the control parameters based on the state of the energy storage device 100 estimated from the measured values ​​acquired in step S101. If the energy storage device 100 is a lithium-ion battery, the control unit 301 estimates the lithium-ion diffusion coefficient as a state quantity. The control unit 301 quantifies the estimated state of the energy storage device and stores it in the memory unit 302, calculates the change in state by taking the difference with the previous estimated quantity, and if the calculated change is greater than a threshold, it can decide to update the control parameters.

[0076] If it is determined that the control parameters should not be updated (S102: NO), the control unit 301 terminates the processing according to this flowchart.

[0077] If it is determined that the control parameters should be updated (S102: YES), the control unit 301 identifies a mathematical model that represents the characteristics of the energy storage device 100 (step S103). Taking a lithium-ion battery as an example, the control unit 301 only needs to identify the Newman model described above.

[0078] Next, the control unit 301 derives control parameters to be set by the control device 210 to fit the identified mathematical model (step S104). Taking the lithium-ion battery described above as an example, the control unit 301 only needs to derive a lower limit (lower voltage limit) for the terminal voltage. Alternatively, the control unit 301 may derive control parameters to control the upper limit (upper voltage limit) for the terminal voltage, the rest time after charging, and the current flowing through the energy storage device 100. The control unit 301 may arbitrarily set control parameters to be updated based on the SOC, battery temperature, etc. In this case, the control unit 301 may derive control parameters within a pre-set range, taking into consideration the impact on the energy storage device 100 and its surrounding components.

[0079] Next, the control unit 301 transmits the derived control parameters to the control device 210 via the communication unit 303 (step S105). At this time, the control unit 301 may also give the control device 210 an instruction to update the control parameters along with the control parameters.

[0080] Figure 9 is a flowchart illustrating the procedure of processing performed by the control device 210. The control unit 211 of the control device 210 determines whether or not it has received control parameters transmitted from the operation management device 300 via the communication unit 215 (step S121). If the control parameters have not been received (S121: NO), the control unit 211 executes the processing from step S123 onward.

[0081] If the control unit 211 determines that it has received control parameters (S121: YES), it updates the control parameters (step S122). At this time, the control unit 211 performs a process to overwrite the control parameters stored in the memory unit 212 with the newly received control parameters.

[0082] Next, the control unit 211 determines whether or not to perform control over the energy storage device 100 (step S123). In other words, the control unit 211 only needs to determine whether or not to perform charge and discharge control over the energy storage device 100. If it is determined that control over the energy storage device 100 should not be performed (S123: NO), the control unit 211 terminates the process according to this flowchart.

[0083] If the control unit 211 determines to perform control on the energy storage device 100 (S123: YES), it performs control on the energy storage device 100 based on the control parameters stored in the memory unit 212 (step S124). If the control parameters have been updated, the control unit 211 can perform control on the energy storage device 100 based on the updated control parameters. Taking a lithium-ion battery as an example, the control unit 211 can perform current control that reduces the fluctuation range of the State of Charge, thereby suppressing capacity imbalances that occur due to increased reaction unevenness and increased activation overvoltage.

[0084] In Embodiment 1, a lithium-ion battery was described as an example of the energy storage device 100. Alternatively, the energy storage device 100 may be an all-solid-state battery, a polymer battery, a lead-acid battery, or the like.

[0085] In Embodiment 1, the Newman model was described as an example of a mathematical model representing the characteristics of a lithium-ion battery. Alternatively, a polynomial model that expresses the open-circuit potential and internal resistance as functions of temperature and state of charge (SOC), such as the NTGK model, may be used, or an equivalent circuit model may be used. Furthermore, the mathematical model may be spatially two-dimensional or three-dimensional.

[0086] (Embodiment 2) Embodiment 2 describes an operation management system for controlling the air conditioning in the installation environment where the energy storage device 100 is installed.

[0087] Figure 10 is a schematic diagram illustrating the overall configuration of the operation management system in Embodiment 2. The operation management system in Embodiment 2 comprises an energy storage device 100, a control device 220 that controls the air conditioning of the installation environment in which the energy storage device 100 is installed, and an operation management device 300 that manages the operation of the energy storage device 100.

[0088] In Embodiment 2, the control device 220 is mounted on an air conditioner 22 having cooling, heating, dehumidifying, and ventilation functions, and controls the air conditioning of the installation environment in which the energy storage device 100 is installed by controlling the operation of the air conditioner 22.

[0089] In the following section, we will describe one of the control methods for the energy storage device 100: a control method that uses the air conditioner 22 to cool the area around the energy storage device 100 (i.e., a control method that lowers the ambient temperature of the energy storage device 100).

[0090] The control device 220 has pre-designed control parameters for controlling the ambient temperature of the energy storage device 100. These control parameters include cooling temperature, airflow rate, and airflow direction. These control parameters are designed during the manufacturing or installation of the energy storage device 100. The control parameters are designed, for example, based on the results of a simulation that estimates the amount of heat generated in the energy storage device 100, so that the temperature of each cell is within a specified range. The designed control parameters are stored in the memory unit 222 of the control device 220 (see Figure 11).

[0091] The control device 220 controls the ambient temperature by reading control parameters stored in the memory unit 222 and controlling the operation of the air conditioner 22 based on the read control parameters. The temperature of each cell constituting the energy storage device 100 is controlled to a temperature within a specified range by controlling the ambient temperature using the air conditioner 22.

[0092] Figure 11 is a block diagram illustrating the internal configuration of the control device 220. The control device 220 in Embodiment 2 comprises a control unit 221, a storage unit 222, a measurement unit 223, an output unit 224, and a communication unit 225. The configurations of the control unit 221, storage unit 222, measurement unit 223, and communication unit 225 are the same as in Embodiment 1, so their explanation is omitted.

[0093] The output unit 224 outputs control signals that control the operation of the heat exchanger, fan, horizontal louvers, vertical louvers, etc., mounted on the air conditioner 22, based on instructions from the control unit 221. The heat exchanger is a device that transfers heat from a high-temperature object to a low-temperature object, and by transferring heat between it and the outdoor unit, it produces cooled or heated air. The fan blows the air cooled or heated by the heat exchanger to the outside of the device. The horizontal louvers and vertical louvers adjust the direction of airflow along the horizontal and vertical directions, respectively. The control unit 221 controls the operation of the heat exchanger, fan, horizontal louvers, vertical louvers, etc., mounted on the air conditioner 22 to realize cooling, heating, and ventilation functions, and controls the ambient temperature of the energy storage device 100.

[0094] Immediately after the introduction of the energy storage device 100, the control device 220 controls the operation of the air conditioner 22 and controls the ambient temperature of the energy storage device 100 using control parameters designed during the manufacturing and introduction of the energy storage device 100. However, if some of the cells constituting the energy storage device 100 deteriorate and their internal resistance increases, the amount of heat generated will increase, and even if the ambient temperature is controlled using the control parameters designed initially, cooling may become insufficient. Since the internal resistance inside the battery is strongly affected by temperature, the terminal voltage of the energy storage device 100 changes significantly with temperature. Furthermore, it is known that the energy storage device 100 is prone to deterioration at high temperatures.

[0095] Therefore, the operation management device 300 determines the amount of heat generated (or resistance) of the degraded cells through simulation trials. For example, the operation management device 300 estimates the amount of heat generated in each cell using a mathematical model that expresses the thermal phenomena inside the battery as shown in Equation 4 below.

[0096]

number

[0097] Here, ρ, C p This is the density (kg / m³) of the energy storage device 100. 3 ), and specific heat (J / kg / K) are expressed. Alternatively, density and specific heat values ​​may be set for each cell. T represents the temperature (K) of the energy storage device 100, and t represents time (s). k, R, and I are the thermal conductance (W / k), resistance (Ω), and current (A) of the energy storage device 100, respectively. The amount of heat generated is the RI in the second term on the right-hand side. 2 It is obtained by [method].

[0098] The operation management device 300 refers to the simulation results of the heat generation and determines whether the heat generation in a particular cell is large or not. The operation management device 300 determines whether the heat generation is large or not by comparing the heat generation estimated by the simulation with a preset threshold. If the operation management device 300 determines that the heat generation in a particular cell is large, it uses the estimated heat generation to perform a thermal fluid simulation to determine the cooling temperature, airflow rate (wind speed), and wind direction for appropriately cooling the energy storage device 100. This simulation may be a brute-force approach, or an optimization method such as the response surface method may be used. For example, the operation management device 300 may use the following equation 5 as the weight function used for optimization. Alternatively, the operation management device 300 may perform the above simulation at regular intervals, or at times instructed by the administrator or other relevant parties.

[0099]

number

[0100] Here, p and q are arbitrarily chosen positive real numbers.

[0101] The operation management device 300 transmits the newly determined cooling temperature, airflow (wind speed), and wind direction, obtained from thermal fluid simulation, to the control device 220 as control parameters to be set in the control device 220. Although heating may be performed in cold regions or in outer space, the method for setting control parameters is the same as for cooling.

[0102] The control device 220 updates the control parameters by overwriting the control parameters stored in the memory unit 222 with the newly received control parameters from the operation management device 300. The control unit 221 of the control device 220 reads the updated control parameters from the memory unit 222 and controls the operation of the air conditioner 22 to control the ambient temperature.

[0103] As described above, the operation management system in Embodiment 2 can suppress the temperature rise of the energy storage device 100 by autonomously finding a setting to appropriately control the ambient temperature using the air conditioner 22, even when a specific cell in the energy storage device 100 deteriorates and generates a large amount of heat.

[0104] (Embodiment 3) Embodiment 3 describes an operation management system for controlling the temperature of the energy storage device 100.

[0105] Figure 12 is a schematic diagram illustrating the overall configuration of the operation management system in Embodiment 3. The operation management system in Embodiment 3 comprises a power storage device 100, a control device 230 for controlling the temperature of the power storage device 100, and an operation management device 300 for managing the operation of the power storage device 100.

[0106] In Embodiment 3, the control device 230 is mounted on a cooling device 23 that cools the energy storage device 100, and controls the temperature of the energy storage device 100 by controlling the operation of the cooling device 23. The cooling device 23 is, for example, a water-cooled (liquid-cooled) cooling device. Alternatively, an air-cooled cooling device may be used.

[0107] In the following section, we will describe a control method for the energy storage device 100, specifically one method of cooling the device using a water-cooled cooling system 23.

[0108] The control device 230 has pre-designed control parameters for controlling the temperature of the energy storage device 100. These control parameters are, for example, proportional control constants, integral control constants, and differential control constants used by the control device 230 when it performs PID control of the water cooling flow rate of the cooling device 23. These control parameters are designed during the manufacturing or installation of the energy storage device 100 and are stored in the memory unit 232 of the control device 230 (see Figure 13).

[0109] The control device 230 reads the control parameters stored in the memory unit 232 and performs PID control of the water cooling flow rate based on the read control parameters. Through this PID control, the control device 230 controls the temperature of the energy storage device 100 to within a specified value.

[0110] Embodiment 3 describes the PID control of the cooling device 23. Alternatively, P control using only proportional control constants may be used, or other feedback control including on / off control may be used.

[0111] Figure 13 is a block diagram illustrating the internal configuration of the control device 230. The control device 230 in Embodiment 3 comprises a control unit 231, a storage unit 232, a measurement unit 233, an output unit 234, and a communication unit 235. The configurations of the control unit 231, storage unit 232, measurement unit 233, and communication unit 235 are the same as in Embodiment 1, so their explanation is omitted.

[0112] The output unit 234 outputs a control signal to control the operation of the cooling device 23 based on instructions from the control unit 231. The cooling device 23 includes a radiator that produces cooling water, a reservoir tank that stores the cooling water, a pump that sends the cooling water outside the device, and an adjustment valve that adjusts the flow rate of the cooling water sent out. The control unit 231 controls the operation of the cooling device 23 and controls the temperature of the energy storage device 100 by, for example, adjusting the flow rate of the cooling water sent out from the cooling device 23.

[0113] Immediately after the introduction of the energy storage device 100, the control device 230 controls the operation of the cooling device 23 and controls the temperature of the energy storage device 100 using control parameters designed during the manufacturing and introduction of the energy storage device 100. However, if some of the cells constituting the energy storage device 100 deteriorate and their internal resistance increases, the amount of heat generated will increase, and even if the operation of the cooling device 23 is controlled using the control parameters designed initially, cooling may become insufficient. The internal resistance inside the battery is strongly affected by temperature, so the terminal voltage of the energy storage device 100 changes significantly with temperature. Furthermore, it is known that the energy storage device 100 is prone to deterioration at high temperatures.

[0114] Therefore, the operation management device 300 determines the temperature of the energy storage device 100 through simulation trials. The operation management device 300 estimates the amount of heat generated in the energy storage device 100 using, for example, a mathematical model that represents the thermal phenomena inside the battery as shown in Equation 6 below.

[0115]

number

[0116] Here, ρ, C p This is the density (kg / m³) of the energy storage device 100. 3 ), represents specific heat (J / kg / K). T is temperature (K), t is time (s), and h is the heat transfer coefficient to the outside air (W / (m). 3 K)), S is the outer surface area (m²) of the energy storage device 100. 2 ), Q is the amount of self-heating such as Joule heating (W), and q is the flow rate of the cooling water (m3 / s), A is a constant (J / m 3 )

[0117] The operation management device 300 refers to the simulation results of the heat generation based on Equation 6 and performs PID control on the flow rate of cooling water supplied from the cooling device 23. The PID control is formulated by the following Equation 7.

[0118]

number

[0119] Here, K p The proportional control constant is K. i K is the integral control constant. d T is the differential control constant. s This is the target temperature (K). p ,K i ,K d The way this is handled determines the stability and responsiveness of the control.

[0120] The parameters of the mathematical model represented by equation 6 are determined by the design of the energy storage device 100 during manufacturing. On the other hand, the parameters related to PID control represented by equation 7 are determined by the control design during manufacturing. These parameters are written to the memory unit 232 of the control device 230 during the manufacturing or installation of the energy storage device 100 and are used as control parameters in the initial state.

[0121] However, as the parameters in the mathematical model change due to factors such as the aging of the energy storage device 100, the parameters related to PID control that were initially optimal may no longer necessarily be optimal.

[0122] Therefore, the operation management device 300 in Embodiment 3 identifies a mathematical model that represents the characteristics of the degraded energy storage device 100, and uses the identified mathematical model to redesign the parameters related to PID control.

[0123] Figure 14 is a graph showing the temperature change of the energy storage device 100. In the graph shown in Figure 14, the vertical axis represents the temperature (K) of the energy storage device 100, and the horizontal axis represents the elapsed time (s) since the start of charging.

[0124] The graph shown as a solid line in Figure 14 illustrates the time dependence of the temperature of the energy storage device 100 in its initial manufacturing state. The example in Figure 14 shows that the temperature of the energy storage device 100 rises over time, reaches a maximum temperature, and then settles at a temperature lower than that maximum.

[0125] The energy storage device 100 deteriorates due to repeated charging and discharging. The dashed line graph in Figure 14 shows the time dependence of the temperature of the energy storage device 100. The example in Figure 14 shows that the temperature of the energy storage device 100 rises over time and reaches a temperature even higher than the maximum temperature in the initial manufacturing state.

[0126] The operation management device 300 identifies the characteristics (thermal phenomena in this example) of the degraded energy storage device 100, indicated by the dashed line, using a mathematical model. The operation management device 300 uses the parameter (ρC) in Equation 6. p The mathematical model may be identified by performing an inverse analysis after exhaustively changing V, hS, and A. Alternatively, the operation management device 300 may use optimization software to determine the parameters in equation 6 and identify the mathematical model.

[0127] The operation management device 300 refers to the identified mathematical model and controls the control parameters (K) related to PID control shown in Equation 7. p ,K i ,K dThe following is derived. The operation management device 300 may use, for example, the Ziegler-Nichols limit sensitivity method as an optimization method for PID control. Alternatively, the operation management device 300 may use an optimization method based on the Riccati equation. Furthermore, the operation management device 300 may utilize the optimization functions of commercially available analysis software such as Maple®, ANSYS Twin Builder®, ANSYS Simplorer®, and MATLAB Simulink®. The operation management device 300 may use a 3D finite element method model, a 1D simulation model, or a degenerate model of the 3D finite element method model as a simulation model used to identify control parameters.

[0128] The operation management device 300 uses newly derived control parameters (K p ,K i ,K d The following is sent to the control device 220 as a control parameter to be set in the control device 220.

[0129] The control device 220 updates the control parameters by performing a process to overwrite the control parameters stored in the memory unit 222 with the newly received control parameters from the operation management device 300. The control unit 221 of the control device 220 reads the updated control parameters from the memory unit 222 and controls the operation of the cooling device 23 to control the temperature of the energy storage device 100.

[0130] As described above, the operation management system in Embodiment 3 can appropriately control the temperature of the energy storage device 100 using the cooling device 23, even when the energy storage device 100 deteriorates and generates a large amount of heat, thereby suppressing the temperature rise of the energy storage device 100.

[0131] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not in the sense described above, and all modifications within the sense and scope equivalent to the claims are intended. [Explanation of symbols]

[0132] 100 Energy Storage Devices 210, 220, 230 Control devices 211,221,231 Control Unit 212,222,232 Storage section 213,223,233 Measurement section 214,224,234 Output section 215,225,235 Communications Department 300 Operation management equipment 301 Control Unit 302 Storage section 303 Communications Department 304 Operation section 305 Display section N Communication Network

Claims

1. A control device that performs control related to the energy storage device, The control device and the operation management device of the energy storage device are communicated to each other. Equipped with, The control device is A memory unit for storing control parameters, A control unit that executes the control based on the control parameters stored in the storage unit. Equipped with, The aforementioned operation management device is A detection unit for detecting the state of the energy storage device, A derivation unit that determines whether or not to update the control parameters according to the detection result from the detection unit, and derives the control parameters to be set in the control device if it is determined that the control parameters should be updated, A transmission unit that transmits the control parameters derived by the derivation unit to the control device. Equipped with, The control device is Update unit updates the control parameters stored in the storage unit based on the control parameters received from the operation management device. Equipped with An operation and management system for energy storage devices.

2. The aforementioned derivation section is, Based on the detection results from the detection unit, a mathematical model representing the characteristics of the energy storage device is identified. The control parameters to be set in the control device are derived to fit the identified mathematical model. The operation management system according to claim 1.

3. The derivation unit periodically derives control parameters that should be set in the control device. The operation management system according to claim 1 or claim 2.

4. The derivation unit calculates the amount of change in the state detected by the detection unit, and if the calculated amount of change is greater than a threshold, it derives the control parameter that should be set in the control device. The operation management system according to claim 1 or claim 2.

5. The control is the charging and discharging control of the energy storage device. An operation management system according to any one of claims 1 to 4.

6. The aforementioned control is the control of an air conditioner that provides air conditioning for the installation environment of the energy storage device. An operation management system according to any one of claims 1 to 4.

7. The control is temperature control of the energy storage device. An operation management system according to any one of claims 1 to 4.

8. A detection unit that detects the status of the energy storage device, A derivation unit that determines whether or not to update the control parameters for the energy storage device based on the detection result from the detection unit, and derives the control parameters that should be set in the control device that executes control related to the energy storage device if it is determined that the control parameters should be updated, A transmission unit transmits the control parameters derived by the derivation unit to the control device in order to update the control parameters used in the aforementioned control. An operation and management device for energy storage devices.

9. The status of the energy storage device is detected, The system determines whether or not to update the control parameters for the energy storage device based on the detection result of the aforementioned state, and if it is determined that the control parameters should be updated, it derives the control parameters that should be set in the control device that executes control related to the energy storage device. To cause the control device to update the control parameters used in the aforementioned control, the derived control parameters are transmitted to the control device. Operation and management methods for energy storage devices.

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