Power storage device monitoring system and power storage device monitoring method, and power storage system

Abstract

To provide a power storage device monitoring system capable of accurately grasping the internal state of the energy storage device, and frequently updating information.SOLUTION: A disclosed power storage device monitoring system 10 includes: a data collection unit 111 that collects first internal state data of a power storage device 20 in a first period and collects part of a second internal state data the data amount of which is larger than the first internal state data; and an internal state estimation unit 113 that calculates and outputs the internal state of the power storage device 20 included in the second internal state data using the first internal state data as input. Preferably, the data collection unit 111 completes the collection of the second internal state data in a second period, which is longer than the first period.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a power storage device monitoring system and a power storage device monitoring method for monitoring the state of a power storage device, and a power storage system. [Background technology]

[0002] Because the output of solar and wind power generation fluctuates depending on the weather and the time of day, it is expected that power storage devices using energy storage elements will be used to adjust supply and demand in the power grid. By introducing energy storage devices, for example, it is possible to store electricity during the daytime when the amount of electricity generated by solar power generation is relatively high, and release and supply electricity at night when electricity demand is relatively high. To meet customer needs, such energy storage devices are becoming increasingly large in capacity and are now composed of a huge number of energy storage elements. To safely operate energy storage devices, an energy storage device monitoring system that constantly monitors the status of these energy storage elements is essential.

[0003] However, as the number of storage elements increases, the internal state quantities of the power storage device to be monitored also increase, which increases the time required for data communication between the power storage device monitoring system and the power storage device, resulting in a problem of insufficient information updates in the power storage device monitoring system.

[0004] Digital twins of power storage devices have been introduced to monitor the internal state of the device. A digital twin is a digital computer replica of the device. This digital twin can monitor the internal state of the device by mimicking (i.e., simulating) the behavior of the device and sequentially calculating state quantities such as the battery's State of Charge (SOC) and State of Health (SOH). Furthermore, using this digital twin as a simulation model can be useful for optimal capacity design and operational planning of the device.

[0005] A data processing device described in Patent Document 1 is a technology related to a power storage device monitoring system that can improve the accuracy of diagnosis, estimation, and prediction of internal state quantities of a power storage device. Patent Document 1 states that "the data processing device includes: a storage unit that stores a judgment model using an autoencoder that is trained to reproduce measurement data when measurement data measured for each storage element or for each storage element group obtained by grouping a plurality of storage elements is input; and an identification unit that identifies measurement data obtained from a different storage element that deviates from an assumed model of the storage element in the measurement data for each storage element or for each storage element group based on an error between the reproduction data output when the measurement data for each storage element or for each storage element group is input to the judgment model." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7390310 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, when the number of storage elements is enormous, the time required for data communication becomes long, and therefore the time required for the power storage device monitoring system to collect information on the internal state of each storage element becomes long. However, Patent Document 1 does not describe how to deal with this. In other words, the conventional technology described in Patent Document 1 does not take into consideration any measures to deal with the long time required to collect information on the internal state of each storage element of the power storage device, and it is difficult to say that a power storage device made up of a huge number of storage elements can be operated safely.

[0008] The present invention has been made in consideration of the above background, and aims to provide a power storage device monitoring system and a power storage device monitoring method that can accurately grasp the internal state of a power storage device and update information frequently, as well as a power storage system that has the power storage device monitoring system. [Means for solving the problem]

[0009] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes multiple means for solving the above problems, and one example is a power storage device monitoring system including: a data collection unit that collects first internal state data of the power storage device and collects a portion of second internal state data, the amount of data being larger than the first internal state data, during a first period; and an internal state estimation unit that uses the first internal state data as input, calculates the internal state of the power storage device included in the second internal state data, and outputs the calculated value. Preferably, the data collection unit completes collection of the second internal state data during a second period that is longer than the first period.

[0010] Also, the present invention is a power storage device monitoring method that executes, in a first period, the following processes: a processing step of collecting first internal state data of the power storage device, a processing step of collecting a portion of second internal state data having a larger amount of data than the first internal state data, and a processing step of using the first internal state data as input to calculate and output the internal state of the power storage device included in the second internal state data. Preferably, the collection of the second internal state data is completed in a second period that is longer than the first period. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a power storage device monitoring system, a power storage device monitoring method, and a power storage system having the power storage device monitoring system, which can accurately grasp the internal state of a power storage device and update information frequently. Problems, configurations, and effects other than those described above will become apparent from the following description of the mode for carrying out the invention (hereinafter referred to as "embodiments"). [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram showing the overall configuration of a power storage system of the present invention including a power storage device monitoring system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a configuration example of a power storage device. [Figure 3] 1 is a block diagram showing an example of the configuration of a power storage device monitoring system according to an embodiment of the present invention; [Figure 4] 2 is a block diagram showing an example of the hardware configuration of a calculation unit of the power storage device monitoring system according to one embodiment of the present invention. FIG. [Figure 5] 4 is a flowchart showing an example (part 1) of the operation flow of a calculation unit of the power storage device monitoring system according to one embodiment of the present invention. [Figure 6] 5 is a flowchart showing an example (part 2) of the operation flow of the calculation unit of the power storage device monitoring system according to one embodiment of the present invention. [Figure 7] 3 is a diagram illustrating a data collection method (part 1) of a data collection unit in a calculation unit of a power storage device monitoring system according to one embodiment of the present invention. FIG. [Figure 8] 5 is a diagram illustrating a data collection method (part 2) of the data collection unit in the calculation unit of the power storage device monitoring system according to one embodiment of the present invention. FIG. [Figure 9] 3 is a diagram illustrating a data processing method of a data processing unit in a calculation unit of a power storage device monitoring system according to an embodiment of the present invention. FIG. [Figure 10] 10 is a flowchart showing an example of processing by an internal state estimation unit in a calculation unit of the power storage device monitoring system according to one embodiment of the present invention. [Figure 11] 3 is a diagram illustrating the operation principle of an internal state estimation unit in a calculation unit of a power storage device monitoring system according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functions or configurations are designated by the same reference numerals, and redundant explanations may be omitted.

[0014] <Electricity storage system> Fig. 1 is a block diagram showing the overall configuration of a power storage system 1 of the present invention, which includes a power storage device monitoring system 10 according to one embodiment of the present invention. As shown in Fig. 1, the power storage system 1 is configured to include the power storage device monitoring system 10, a power storage device 20, a converter 30, and a transformer 40, and is connected to a power grid 2 via a grid-tie point T1. The power grid 2 is a system for supplying power to power receiving facilities of consumers.

[0015] In the power storage system 1, the power storage device monitoring system 10 is a system that monitors the state of the power storage device 20. The power storage device 20 is an electrochemical power storage device, and is connected to the power grid 2 via a converter 30, a transformer 40, and a grid-tied point T1. The converter 30 converts the voltage of AC power. In general, the voltage on the power grid 2 side is higher than the voltage on the power storage device 20 side. The converter 30 converts DC power on the power storage device 20 side and AC power on the transformer 40 side, and vice versa. The converter 30 may also have a function of internally transforming DC power.

[0016] <Electricity storage device> The power storage device 20 stores power as needed and supplies power as needed. For example, the power storage device 20 stores power during the daytime when the amount of power generated by solar power generation is relatively large and there is surplus power in the power system 2, and supplies power at night when power demand is relatively high. The power storage device 20 contributes to the operation of the power system 2 by receiving and transmitting active power and reactive power. In other words, the power storage device 20 responds to increases and decreases in power demand by transmitting and receiving active power. In addition, the power storage device 20 contributes to the stable operation of the power system 2 by generating reactive power that compensates for reactive power in the power system 2.

[0017] An example of the electrochemical power storage device 20 is a storage battery that stores electricity by converting it into chemical energy. In addition, examples of power storage devices 20 that operate on a different principle from a storage battery that stores electricity by converting it into chemical energy include a supercapacitor (electric double layer capacitor) and a water electrolyzer (electrolyzer). In the following, a storage battery will be used as an example of the power storage device 20.

[0018] Fig. 2 is a block diagram showing a configuration example of the power storage device 20. The power storage device 20 is configured by connecting a plurality of battery modules 21 in series and / or in parallel. The power storage device 20 is then connected to the converter 30 shown in Fig. 1 via a connection point T2. Fig. 2 shows a configuration example in which three battery strings 22, each of which has three battery modules 21 connected in series, are connected in parallel, but the configuration of the power storage device 20 is not limited to this.

[0019] A module management device 23 is connected to the battery module 21. The module management device 23 monitors the internal state of the battery module 21 and transmits the data to a string management device 24, which is a higher-level device. The string management device 24 collects and processes the data from the module management device 23, and further transmits the data to a bank management device 25, which is a higher-level device. The bank management device 25 then collects and processes the data from the string management device 24 and transmits the data to the power storage device monitoring system 10.

[0020] The power storage device 20 may be configured so that the string management device 24 and the bank management device 25 are not installed, and data is sent directly from the module management device 23 to the power storage device monitoring system 10. Further, a configuration may be adopted in which additional management devices are installed between the module management device 23 and the string management device 24, and between the string management device 24 and the bank management device 25. The hierarchy of these management devices is determined according to the scale of the power storage device 20.

[0021] The battery module 21 is configured by connecting a plurality of power storage elements in series and / or parallel. The power storage elements are, for example, lithium ion battery cells. That is, in this example, the power storage device 20 is a lithium ion battery type power storage device. The power storage elements may include sensors that measure the voltage and temperature of the lithium ion battery cells, and a balancing circuit that equalizes the voltage between the lithium ion battery cells.

[0022] The internal state of the battery module 21 is, for example, at least one of the current, voltage, temperature, charging rate (SOC: State of Charge), deterioration rate (SOH: State of Health), and charge / discharge allowable power (SOP: State of Power).

[0023] In addition to the data received from the module management device 23, the string management device 24 and the bank management device 25 may collect data from the sensors 26. The sensors 26 are, for example, current sensors, voltage sensors, and temperature sensors. The current sensors measure, for example, the current Isys flowing through the entire power storage device 20 and the current Istr (denoted as Istr1, Istr2, and Istr3 in FIG. 2 ) flowing through each battery string 22. The voltage sensors measure, for example, the voltage Vsys of the power storage device 20. The temperature sensors measure, for example, the ambient temperature of the power storage device 20.

[0024] <Power storage device monitoring system> 3 is a block diagram showing an example of the configuration of a power storage device monitoring system 10 according to one embodiment of the present invention. The power storage device monitoring system 10 according to this embodiment includes a calculation unit 11, a display unit 12, and an operation unit 13.

[0025] The calculation unit 11 includes a data collection unit 111, a data processing unit 112, an internal state estimation unit 113, an update unit 114, and a verification unit 115. The display unit 12 is, for example, a display screen, a printer, etc. Examples of the display screen include an LCD (Liquid Crystal Display), an EL (Electro Luminescence) panel, an organic EL panel, etc. The operation unit 13 is, for example, composed of switches, buttons, a keyboard, a touch panel, a mouse, a microphone, etc.

[0026] [Example of specific configuration of the calculation unit] In the calculation unit 11, the data collection unit 111 collects first internal state data from the power storage device 20. Details of the first internal state data will be described later. The data collection unit 111 further collects a portion of second internal state data from the power storage device 20. Details of the second internal state data will also be described later.

[0027] The data processing unit 112 performs a process of interpolating and completing missing data of the second internal state data. The internal state estimation unit 113 introduces a digital twin as a simulation model, and performs a process of estimating the internal state of the power storage device 20 using the first internal state data. The update unit 114 performs a process of updating the parameters of the internal state estimation unit 113 when necessary, specifically when the calculation results of the internal state estimation unit 113 deviate from the second internal state data. The verification unit 115 performs a process of comparing the data (measured values) output by the data processing unit 112 with the data (calculated values) output by the internal state estimation unit 113, and determining whether there is a significant error.

[0028] [Example of hardware configuration for the calculation unit] FIG. 4 is a block diagram showing an example of the hardware configuration of the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention.

[0029] The calculation unit 11 includes a processor 1101, a communication interface 1102, a main memory device 1103, an auxiliary memory device 1104, an input / output interface 1105, and a bus 1106 that communicatively connects these components. Hereinafter, the interface will be referred to as "I / F."

[0030] The processor 1101 is a central processing unit that controls the operation of each unit of the calculation unit 11. The processor 1101 can be configured, for example, with a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or an ASIC (Application Specific Integrated Circuit). The processor 1101 deploys a program stored in the auxiliary storage device 1104 in a working area of ​​the main storage device 1103 so that the program can be executed.

[0031] The communication I / F 1102 is a component that has a function of transmitting and receiving data between the calculation unit 11 and an external device.

[0032] The main memory device 1103 stores programs executed by the processor 1101 and data processed by the processor 1101. The main memory device 1103 can be configured with a flash memory, a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

[0033] The auxiliary storage device 1104 stores various programs and various data. The auxiliary storage device 1104 stores, for example, an OS (Operating System), various programs, and various data such as tables. The auxiliary storage device 1104 can be configured with a silicon disk including nonvolatile semiconductor memory (for example, flash memory and EPROM (Erasable Programmable ROM)), a solid state drive device, a hard disk device (HDD: Hard Disk Drive), or the like.

[0034] The input / output I / F 1105 accepts operations and instructions from an operator who operates the operation unit 13. The input / output I / F 1105 also outputs data and information processed by the processor 1101 and data and information stored in the main memory device 1103 and the auxiliary memory device 1104 to the display unit 12.

[0035] [Example of calculation flow (part 1)] FIG. 5 is a flowchart showing an example (part 1) of the operation flow of the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention.

[0036] 5, in the operation flow example (part 1), first, the data collection unit 111 collects first internal state data from the power storage device 20 (step S11). Next, the data collection unit 111 collects a part of second internal state data from the power storage device 20 (step S12).

[0037] Next, the internal state estimation unit 113 estimates the internal state of the power storage device 20 using the first internal state data (step S13), and then the data collection unit 111 determines whether or not collection of the second internal state data has been completed (step S14). If the data collection unit 111 determines that collection has been completed (YES in S14), the flow ends. If the data collection unit 111 determines that collection has not been completed (NO in S14), the flow returns to step S11, and the processes of steps S11 to S13 are repeated until the data collection unit 111 completes collection of the second internal state data.

[0038] Hereinafter, the time from the start of the process in step S11 to the end of the process in step S13 shown in Fig. 5 will be referred to as a first cycle, and the time from the start of the process in the flowchart in Fig. 5 to the end of the process will be referred to as a second cycle.

[0039] [Example of calculation flow (part 2)] 6 is a flowchart showing a second example of the operation flow of the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention. The second example of the operation flow is a modified example of the first example of the operation flow.

[0040] In the flowchart of FIG. 6, the processes from step S21 to step S24 are the same as the processes from step S11 to step S14 in the operation flow example (part 1) shown in FIG. 5, and therefore a description thereof will be omitted.

[0041] In the operational flow example (part 2), if the data collection unit 111 determines that collection of the second internal state data has been completed (YES in S24), it proceeds to step S25, and if it determines that collection has not been completed (NO in S24), it returns to step S21 and repeats the processes from step S21 to step S23 until collection of the second internal state data is completed.

[0042] If the data collection unit 111 determines that collection of the second internal state data has been completed (YES in S24), the verification unit 115 verifies the estimation result, specifically, performs a process of comparing the calculation result of the internal state estimation unit 113 with the second internal state data (step S25). Next, the update unit 114 updates the parameters of the internal state estimation unit 113 if necessary, that is, if the calculation result of the internal state estimation unit 113 deviates from the second internal state data (step S26).

[0043] [Regarding the first and second internal state data] Here, the first and second internal state data will be explained.

[0044] The first internal state data includes data necessary for the internal state estimation unit 113 to estimate the internal state of the power storage device 20. The first internal state data includes, for example, the current Isys, the current Istr, and the voltage Vsys output by the sensor 26. The first internal state data may also include an alarm signal output by the module management device 23 or the string management device 24. In this way, the power storage device monitoring system 10 can respond quickly to an abnormality.

[0045] The second internal state data includes data necessary for the verification unit 115 to verify the accuracy of the calculation results of the internal state estimation unit 113. The second internal state data includes, for example, at least one of the current, voltage, temperature, charging rate, deterioration rate, and allowable charge / discharge power output by the module management device 23. Therefore, the amount of data in the second internal state data is greater than the amount of data in the first internal state data. In other words, the time required to communicate the second internal state data is longer than the time required to communicate the first internal state data.

[0046] [Calculation part: Data collection method (part 1)] FIG. 7 is a diagram illustrating a data collection method (part 1) of the data collection unit 111 in the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention.

[0047] 7 shows an example in which data is collected from the sensor 26 and four module management devices 23 for ease of understanding. However, in reality, there are multiple sensors 26 and the number of module management devices 23 is more than four. In the following, the sensor 26 will be referred to as Sensor, the module management device 23 as BMS, the first internal state data as dataset1, and the second internal state data as dataset2.

[0048] In the first first cycle (n=1), first internal state data is collected from each of Sensor, BMS1, BMS2, BMS3, and BMS4, and then second internal state data is collected from BMS1. Then, in the second first cycle (n=2), first internal state data is collected from each of Sensor, BMS1, BMS2, BMS3, and BMS4, and then second internal state data is collected from BMS2. Similarly, when n=3, second internal state data is collected from BMS3, and when n=4, second internal state data is collected from BMS4.

[0049] In this way, by cyclically changing the collection target of the second internal state data, it is possible to finally collect the second internal state data from all module management devices 23.

[0050] If the amount of second internal state data is large, the second internal state data may be divided. For example, when n=1, second internal state data A is collected from BMS1, and when n=2, second internal state data B is collected from BMS1. In this way, the first period can be set shorter.

[0051] [Calculation part: Data collection method (part 2)] 8 is a diagram illustrating a data collection method (part 2) of the data collection unit 111 in the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention. The data collection method (part 2) is another example of the data collection method of the data collection unit 111. In other words, the data collection method (part 2) is a modified example of the data collection method (part 1).

[0052] In this example of data collection method (part 2), when n=1, BMS1 is the collection target for the second internal state data, and first, the first internal state data and the second internal state data are collected from BMS1, and then the first internal state data is collected from the remaining BMSs. Next, when n=2, BMS2 is the collection target for the second internal state data, and after collecting the first internal state data from BMS1, the first internal state data and the second internal state data are collected from BMS2, and then the first internal state data is collected from the remaining BMSs.

[0053] According to this second example of data collection method, fewer switching of communication targets is required compared to the first example of data collection method, and therefore communication speed can be improved.

[0054] [Calculation section: Data processing method] FIG. 9 is a diagram illustrating a data processing method of the data processing unit 112 in the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention.

[0055] The data collection unit 111 cyclically collects the second internal state data in a first cycle. In the example of Fig. 9, the first cycle is 5 seconds, and time-series data of the 40th cell voltage (V_cell40) collected as the second internal state data from BMS1, BMS2, BMS3, and BMS4 is shown.

[0056] Since data is collected cyclically, there are gaps in the data. The data processing unit 112 interpolates the gaps in the data from the previous and next data. The data processing unit 112 may also compensate for gaps in the data caused by measurement or communication errors. In this way, by having the data processing unit 112 that compensates for the gaps in the data, the power storage device monitoring system 10 can monitor the internal state of the power storage device 20 frequently and accurately.

[0057] [Calculation section: Internal state estimation section] The internal state estimation unit 113 may be configured as an equivalent circuit model that represents the power storage device 20 as an electric circuit. The internal state estimation unit 113 may also include a model (mathematical model) that further simulates electrochemical phenomena and thermal phenomena in order to estimate the internal state of the power storage device 20 in more detail. The operating principle of the internal state estimation unit 113 will be described with reference to Figs. 10 and 11.

[0058] FIG. 10 is a flowchart showing an example of processing by the internal state estimation unit 113 in the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention.

[0059] The internal state estimation unit 113 calculates the combined resistance and combined voltage of the power storage device 20 (step S31), and then calculates the current of each battery string 22 that constitutes the power storage device 20 (step S32). Details of the processes in steps S31 and S32 are described below.

[0060] FIG. 11 is a diagram illustrating the operation principle of the internal state estimation unit 113 in the calculation unit 11 of the power storage device monitoring system 10 according to one embodiment of the present invention.

[0061] Assuming that the electrical characteristics of each storage element are equivalent to an electrical circuit in which a resistance element and a voltage source are connected in series, Thévenin's theorem, a branch of electrical circuit theory, allows a power storage system in which multiple storage elements are connected in series and / or in parallel to be represented by an electrical circuit in which one voltage source (Vc) and resistance element (Rc) are connected in series.

[0062] For simplicity, Fig. 11 shows an example in which four storage elements are connected in two series and two parallel configurations, but the method described below can be applied to cases in which the number of series and parallel connections is three or more. In Fig. 11, R1 to R4 are internal resistances of the storage elements, and V1 to V4 are voltages of the storage elements.

[0063] (Processing of step S31) First, the processing of step S31 will be described. In Fig. 10, the combined resistance and combined voltage in the processing of step S31 correspond to Rc and Vc, respectively. According to Thevenin's theorem, the combined resistance Rc and combined voltage Vc are expressed by (Equation 1) and (Equation 2), respectively. Rc=(R1+R2)×(R3+R4) / (R1+R2+R3+R4) (Formula 1) Vc=V1+V2-(R1+R2)×Icc (Formula 2)

[0064] Here, Icc is the current in the closed circuit and is expressed by (Equation 3). Icc=(V1+V2-V3-V4) / (R1+R2+R3+R4)...(Formula 3)

[0065] (Processing of step S32) Next, the processing of step S32 will be described. In Fig. 10, the string currents in the processing of step S31 correspond to I12 and I34. If the current flowing through the power storage device 20 is Isys and the voltage is Vsys, then Equation 4 holds true in accordance with electrical circuit theory. Vsys=Vc+Rc×Isys (Formula 4)

[0066] Next, in accordance with electrical circuit theory, the shunt currents I12 and I34 in the parallel circuit are expressed by (Equation 5) and (Equation 6), respectively. I12=(Vsys-V1-V2) / (R1+R2) (Formula 5) I34=(Vsys-V3-V4) / (R3+R4) (Formula 6)

[0067] By using the above-mentioned relational expressions, it is possible to calculate other internal states that have not been measured from any part of the internal states that have been measured. Specifically, the internal state estimation unit 113 stores the internal resistance and voltage of each storage element as parameters, and can output Vsys, I12, and I34 with Isys as input.

[0068] Furthermore, by using the above-mentioned relationship, it is possible to interchange inputs and outputs. For example, it is possible to use Vsys as an input and output Isys, I12, and I34. Furthermore, by using the law of voltage division in an electric circuit, the internal state estimation unit 113 can input the value of each string current and output the voltage and resistance value of each storage element.

[0069] [Calculation section: Verification section, Update section] 3 compares the data (measured value) output by the data processing unit 112 with the data (calculated value) output by the internal state estimation unit 113, and determines whether there is any significant error. In other words, the verification unit 115 determines the validity of the model of the internal state estimation unit 113. For example, if the measured value of Vsys is Vsys_1 and the calculated value of Vsys is Vsys_2, the verification unit 115 determines that the internal state estimation unit 113 is inaccurate when the relational expression (Equation 7) shown below is true. |Vsys_1-Vsys_2| / Vsys_1>ε1 (Formula 7) where ε1 is the error threshold for Vsys.

[0070] As a modified example, the verification unit 115 may periodically calculate (Equation 7), and when the number of times (Equation 7) is true exceeds a predetermined number of times, determine that the internal state estimation unit 113 is inaccurate. Also, Vsys_1 and Vsys_2 may be moving average values ​​over a predetermined time. In this way, the verification unit 115 can more accurately determine the validity of the model of the internal state estimation unit 113.

[0071] Instead of Vsys, it is also possible to use other internal states collected by the data collection unit 111. For example, when I12 and I34 are used, (Equation 8) and (Equation 9) are applied. |I12_1-I12_2| / I12_1>ε2 (Formula 8) |I34_1-I34_2| / I34_1>ε3 (Formula 9) where I12_1 and I12_2 are the measured and calculated values ​​of I12, respectively, I34_1 and I34_2 are the measured and calculated values ​​of I34, respectively, and ε2 and ε3 are the error thresholds for I12 and I34, respectively. In this way, by using a plurality of internal states, the verification unit 115 can more accurately determine the validity of the model of the internal state estimation unit 113.

[0072] When the verification unit 115 determines that the internal state estimation unit 113 is inaccurate, the update unit 114 updates the parameters of the model that constitutes the internal state estimation unit 113. Specifically, the update unit 114 updates the value of the voltage source (Vc) and the value of the resistance element (Rc) of each storage element. The value of the voltage source (Vc) may be given by a lookup table. This lookup table is sometimes called an SOC-OCV curve.

[0073] The update unit 114 may update the value of the voltage source (Vc) and the value of the resistance element (Rc) based on separately provided battery degradation characteristics. Alternatively, the update unit 114 may increase the value of the voltage source (Vc) and the value of the resistance element (Rc), and if the accuracy has deteriorated when the verification unit 115 next determines the validity of the model, the update unit 114 may conversely decrease the value of the voltage source (Vc) and the value of the resistance element (Rc), and if the accuracy has improved, the update unit 114 may further increase the value of the voltage source (Vc) and the value of the resistance element (Rc).

[0074] [Effects and Elements] In the power storage device monitoring system 10 (monitoring system method) according to this embodiment, in a first period which is a relatively short period, the internal state estimation unit 113 collects first internal state data including data necessary for calculating the internal state of the power storage device 20, and part of second internal state data including other internal states. Then, the targets for collecting the second internal state data are rotated, and collection of all the second internal state data is completed in a second period which is a relatively long period.

[0075] The first period is shorter than the second period. Furthermore, the amount of data of the first internal state data is smaller than the amount of data of the second internal state data. The internal state estimation unit 113 receives the first internal state data as input and calculates the internal state included in the second internal state data. In this way, the power storage device monitoring system 10 can accurately grasp the internal state of the power storage device 20 and update the information frequently. In other words, the power storage device monitoring system 10 can achieve both information updating and accuracy in monitoring.

[0076] The first period is, for example, 10 seconds or less, more preferably 5 seconds or less. Here, "10 seconds or less" means not only strictly within 10 seconds but also substantially within 10 seconds, and various variations arising from design or manufacturing are allowed.

[0077] The second period is, for example, 5 minutes or more, and the greater the number of module management devices 23, the longer the second period. For example, if there are 1,000 module management devices 23, it would take several tens of minutes to collect all the internal states from each module management device 23. However, with the power storage device monitoring system 10 according to this embodiment, even if there are 1,000 module management devices 23, it is possible to grasp the internal states in a short time of within 10 seconds. The power storage device monitoring system 10 according to this embodiment is highly effective when the number of module management devices 23 is huge, for example, 100 or more.

[0078] The verification of accuracy by the verification unit 115 and the update of parameters by the update unit 114 do not have to be performed every time collection of second internal state data is completed. This is because a possible cause of an error between the calculation result of the internal state estimation unit 113 and the actual measurement value is deterioration of the storage element, and deterioration occurs in units of, for example, one month. Therefore, the frequency of the verification of accuracy by the verification unit 115 and the update of parameters by the update unit 114 may be set to once a month.

[0079] Furthermore, according to the power sculpture system 1 of the present invention, the power storage device monitoring system 10 of this embodiment is used as a power storage device monitoring system that monitors the status of the power storage device 20, so that the internal status of the power storage device 20 can be accurately grasped and the information can be updated frequently.

[0080] <<Variations>> The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. [Explanation of symbols]

[0081] REFERENCE SIGNS LIST 1...power storage system, 2...power system, 10...power storage device monitoring system, 11...calculation unit, 12...display unit, 13...operation unit, 20...power storage device, 21...battery module, 22...battery string, 23...module management device, 24...string management device, 25...bank management device, 26...sensor, 30...converter, 40...transformer, 111...data collection unit, 112...data processing unit, 113...internal state estimation unit, 114...update unit, 115...verification unit

Claims

1. A power storage device monitoring system for monitoring a state of a power storage device, a data collection unit that collects first internal state data of the power storage device and collects a portion of second internal state data having a larger data volume than the first internal state data during a first period; an internal state estimation unit that receives the first internal state data as input, calculates the internal state of the power storage device included in the second internal state data, and outputs the calculated internal state; Equipped with Power storage device monitoring system.

2. The data collection unit completes collection of the second internal state data in a second period that is longer than the first period. The power storage device monitoring system according to claim 1 .

3. a data processing unit that interpolates and complements the missing data of the second internal state data; Further equipped The power storage device monitoring system according to claim 1 .

4. The internal state estimation unit includes an electrical equivalent circuit that is configured with a voltage source and a resistance element. The power storage device monitoring system according to claim 1 .

5. The first internal state data includes a current input to or output from the power storage device and / or a voltage of the power storage device. The power storage device monitoring system according to claim 1 .

6. The second internal state data includes at least one of a current, a voltage, a temperature, a charging rate, a deterioration rate, and a charge / discharge allowable power of a plurality of storage elements that constitute the power storage device. The power storage device monitoring system according to claim 1 .

7. a verification unit that compares the second internal state data with a calculation result of the internal state output by the internal state estimation unit; an update unit that updates parameters held by the internal state estimation unit; Further equipped The power storage device monitoring system according to claim 1 .

8. The first period is 10 seconds or less. The power storage device monitoring system according to claim 1 .

9. A module management device that monitors the internal state of the battery modules that make up the power storage device Furthermore, The number of the module management devices is 100 or more. The power storage device monitoring system according to claim 1 .

10. The battery module is composed of a plurality of lithium-ion battery cells. The power storage device monitoring system according to claim 9 .

11. The power storage device is connected to a power grid via a converter that converts the voltage of AC power. The power storage device monitoring system according to claim 1 .

12. A power storage device monitoring method for monitoring a state of a power storage device, comprising: collecting first internal state data of the power storage device in a first period; collecting a portion of second internal state data, the second internal state data having a larger amount of data than the first internal state data; a step of calculating an internal state of the power storage device included in the second internal state data using the first internal state data as an input and outputting the calculated internal state; Execute each process of A method for monitoring an electric power storage device.

13. a power storage device; a power storage device monitoring system that monitors the state of the power storage device; Equipped with The power storage device monitoring system includes: a data collection unit that collects first internal state data of the power storage device and collects a portion of second internal state data having a larger data volume than the first internal state data during a first period; an internal state estimation unit that receives the first internal state data as input, calculates the internal state of the power storage device included in the second internal state data, and outputs the calculated internal state; Equipped with Energy storage system.

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