All-vanadium redox flow battery SOC dual monitoring correction method and system

Abstract

The invention relates to the technical field of batteries, in particular to an all-vanadium redox flow battery SOC dual monitoring correction method and system. The method comprises the following steps: acquiring first SOC data through potential monitoring, wherein the first SOC data comprises a positive charge-discharge state SOC positive, n and a negative charge-discharge state SOC negative, n; second SOC data including SOC positive ', n and SOC negative', n are obtained through electrolyte valence state concentration monitoring; calculating correction coefficients kappa positive and kappa negative according to the first SOC data and the second SOC data; and finally, correcting the third SOC data by using the correction coefficient to obtain an actual SOC value. According to the method, a dual monitoring mode is adopted, the real-time online characteristic of potential monitoring is utilized, the high-precision advantage of electrolyte concentration monitoring is combined, the two monitoring methods are organically combined through a correction coefficient, and the problems that single potential monitoring is affected by hydrogen ion concentration and the electrolyte concentration monitoring cannot realize real-time online monitoring are solved. According to the method, the correction frequency of 0-10 days is designed, the correction timeliness and sampling interference are reasonably balanced, and the accuracy of SOC monitoring is improved.

Description

Technical Field

[0001] The invention relates to the technical field of batteries, and in particular to a method and system for dual monitoring and correction of SOC of an all-vanadium liquid flow battery. Background Art

[0002] In the field of battery technology, accurate monitoring and estimation of the battery's state of charge (SOC) is crucial for battery performance evaluation, life prediction, and maintenance management. SOC is a key parameter in the battery management system (BMS). The SOC of a battery not only affects the battery's operating efficiency, but is also directly related to the battery's safety and service life. Especially in energy storage systems such as the Vanadium Redox Flow Battery (VRFB), accurate SOC monitoring is essential to ensure the performance and life of the battery. The vanadium redox flow battery is an electrochemical energy storage system based on a vanadium salt solution, and its working principle involves the redox reaction of vanadium ions between the positive and negative electrodes. During the operation of the battery, the valence concentration of vanadium ions at the positive and negative electrodes and the change in the battery's potential will directly affect the battery's SOC.

[0003] At present, the potential is usually measured to monitor the change of the valence concentration ratio of the positive and negative vanadium ions online in real time, that is, to monitor the charge and discharge state SOC of the battery.

[0004] However, since the change in potential during the charge and discharge process is not only related to the active ion concentration, but also affected by the change in hydrogen ion concentration, and after long-term cycle operation, the SOC states of the positive and negative electrodes are different, and the changes in the valence concentration of vanadium ions cannot be monitored, the SOC accuracy of the all-vanadium liquid flow battery is low during real-time monitoring. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the problem to be solved by the present invention is how to solve the problem that the change of potential during charging and discharging is not only related to the concentration of active ions, but also affected by the change of hydrogen ion concentration. At the same time, after long-term cyclic operation, the SOC states of the positive and negative electrodes are different. In addition, the change of the valence state concentration of vanadium ions cannot be monitored, which leads to low SOC accuracy of the all-vanadium liquid flow battery during real-time monitoring.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a dual monitoring and correction method for SOC of an all-vanadium liquid flow battery, which comprises obtaining first SOC data of the all-vanadium liquid flow battery to be detected by potential monitoring;

[0009] Acquiring second SOC data of the all-vanadium redox flow battery to be tested by monitoring the electrolyte valence concentration;

[0010] According to the first SOC data and the second SOC data, a correction coefficient of the all-vanadium liquid flow battery to be tested during potential monitoring is obtained;

[0011] According to the correction coefficient, the third SOC data of the all-vanadium redox flow battery to be tested during the potential monitoring process is corrected.

[0012] As a preferred solution of the all-vanadium liquid flow battery SOC dual monitoring and correction method of the present invention, wherein: the first SOC data includes:

[0013] The positive electrode charge and discharge state SOC obtained by potential monitoring 正，n and negative electrode charge and discharge state SOC 负，n ;

[0014] The second SOC data includes the SOC obtained by monitoring the electrolyte valence concentration 正'，n and SOC 负'，n .

[0015] As a preferred solution of the dual monitoring and correction method for SOC of the all-vanadium liquid flow battery described in the present invention, the potential monitoring includes installing a reference electrode and a working electrode at the liquid outlet of the positive electrode storage tank and the liquid outlet of the negative electrode storage tank of the all-vanadium liquid flow battery respectively, and monitoring the changes of the positive electrode potential and the negative electrode potential in real time through a monitoring system.

[0016] As a preferred solution of the dual monitoring and correction method for SOC of the all-vanadium liquid flow battery described in the present invention, the electrolyte valence concentration monitoring includes installing a micro-injection controller at the liquid outlet of the positive electrode storage tank and the liquid outlet of the negative electrode storage tank of the all-vanadium liquid flow battery, respectively, injecting electrolyte into the liquid collection bottle through the micro-injection controller, and obtaining the positive and negative electrode electrolyte valence concentrations through ultraviolet visible spectrophotometer or potentiometric titrator testing.

[0017] As a preferred solution of the dual monitoring and correction method for SOC of the all-vanadium liquid flow battery of the present invention, the correction coefficient is obtained according to the first SOC data and the second SOC data, including:

[0018] Calculate the positive electrode correction factor κpositive = SOC 正'，n / SOC 正，n ;

[0019] Calculate the negative electrode correction factor κ negative = SOC 负'，n / SOC 负，n .

[0020] As a preferred solution of the dual monitoring and correction method for SOC of the all-vanadium liquid flow battery of the present invention, wherein: correcting the third SOC data according to the correction coefficient includes:

[0021] Calculate the actual SOC of the positive electrode: SOC 正，实 =κpositive×SOC 正 ;

[0022] Calculate the actual SOC of the negative electrode: SOC 负，实 =κ negative × SOC 负 .

[0023] As a preferred solution of the dual monitoring and correction method for SOC of all-vanadium liquid flow battery described in the present invention, the correction coefficient is determined at a frequency of 0 to 10 days.

[0024] In a second aspect, an embodiment of the present invention provides a dual monitoring and correction system for SOC of an all-vanadium liquid flow battery, which includes a potential monitoring module for obtaining first SOC data of an all-vanadium liquid flow battery to be detected;

[0025] An electrolyte concentration monitoring module, used for obtaining the second SOC data of the all-vanadium liquid flow battery to be tested;

[0026] A correction coefficient calculation module, used for obtaining a correction coefficient of the all-vanadium liquid flow battery to be tested during potential monitoring according to the first SOC data and the second SOC data;

[0027] The SOC correction module is used to correct the third SOC data of the all-vanadium liquid flow battery to be detected during the potential monitoring process according to the correction coefficient.

[0028] In a third aspect, an embodiment of the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the all-vanadium liquid flow battery SOC dual monitoring and correction method as described in the first aspect of the present invention are implemented.

[0029] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the all-vanadium liquid flow battery SOC dual monitoring and correction method as described in the first aspect of the present invention are implemented.

[0030] The beneficial effects of the present invention are as follows: less sampling is required during the monitoring of electrolyte concentration, which does not affect the battery capacity; the monitoring process does not directly contact the electrolyte, and no impurities are introduced into the electrolyte. When the electrolyte concentration is monitored regularly, the changes in the vanadium ion concentrations of the positive and negative electrolytes of the battery can also be monitored, and whether the charging and discharging states of the positive and negative electrodes are consistent can be monitored.

[0031] By conceiving the correction coefficient in the present application, the defect that the electrolyte concentration cannot be monitored online in real time can be compensated. Therefore, although the real-time online monitoring is still carried out through the potential monitoring method, after the correction, the correction result actually also takes into account the influence of the change in ion concentration, so that the correction result is more accurate, and finally realizes the monitoring of the SOC of the all-vanadium liquid flow battery in a simple, efficient and accurate manner without cost.

[0032] It can better adapt to different battery types and working conditions, and at the same time provides an effective correction mechanism to improve the accuracy of SOC estimation and the stability of battery operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A flow chart of the dual monitoring and correction method for SOC of all-vanadium liquid flow battery;

[0035] Figure 2 A computer device diagram for the dual monitoring and correction method of SOC of all-vanadium liquid flow battery;

[0036] Figure 3 This is a potential monitoring system diagram for the SOC dual monitoring correction method of all-vanadium liquid flow battery;

[0037] Figure 4 This is the reaction diagram of the positive and negative electrode storage tanks for the dual monitoring and correction method of SOC of the all-vanadium liquid flow battery. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0041] Example 1

[0042] Reference Figure 1-2 , which is the first embodiment of the present invention, and provides a dual monitoring and correction method for SOC of an all-vanadium liquid flow battery, comprising:

[0043] S100: Acquire first SOC data of the all-vanadium liquid flow battery to be tested by potential monitoring;

[0044] S101: The first SOC data includes:

[0045] The positive electrode charge and discharge state SOC obtained by potential monitoring 正，n and negative electrode charge and discharge state SOC 负，n The second SOC data includes the SOC obtained by monitoring the electrolyte valence concentration. 正'，n and SOC 负'，n .

[0046] In the embodiment of the present application, the first SOC data includes the positive electrode charge and discharge state SOC obtained by potential monitoring. 正，n and negative electrode charge and discharge state SOC 负，n .

[0047] Specifically, potential monitoring can be achieved by installing a reference electrode and a working electrode at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank of the all-vanadium redox flow battery. The reference electrode is a mercurous sulfate electrode, and the working electrode can be a platinum sheet electrode or a platinum wire electrode. These electrodes are connected to a monitoring system, and the changes in the positive electrode potential and the negative electrode potential are monitored in real time through the monitoring system.

[0048] In an optional embodiment, the reference electrode may also be other types of reference electrodes, such as a silver chloride electrode, a calomel electrode, etc. The following factors need to be considered when selecting a reference electrode:

[0049] Stability of electrode potential: The reference electrode should maintain a constant potential during long-term use; Temperature coefficient: The sensitivity of the electrode potential to temperature changes should be as small as possible; Response time: The electrode should be able to respond quickly to changes in the potential in the electrolyte; Service life: The electrode should have a long service life to avoid frequent replacement; Anti-interference ability: The electrode should have good anti-interference ability to reduce the impact of external factors.

[0050] In the embodiments of the present application, the working electrode adopts a platinum sheet electrode or a platinum wire electrode, and the following characteristics are mainly considered: good catalytic activity: platinum has excellent catalytic properties and can promote the electrode reaction; high chemical stability: platinum has good chemical stability in the electrolyte and is not easily corroded; good electrical conductivity: platinum has high electrical conductivity, which is conducive to the conduction of electrical signals; high mechanical strength: platinum has high mechanical strength and can withstand the stress of long-term use; controllable surface state: the surface state of the platinum electrode is easy to control, which is conducive to obtaining stable measurement results.

[0051] It should be noted that the installation position of the electrode has an important influence on the measurement results. Installing the electrode at the outlet of the liquid storage tank can monitor the potential changes of the flowing electrolyte in real time, but the following points should be noted: the electrode should be installed firmly to avoid loosening during the measurement process; the electrode surface should be kept clean and cleaned and maintained regularly; the electrode should be in full contact with the electrolyte to ensure the stability of the measurement signal; the electrode lead should be waterproof and insulated; the performance of the electrode should be checked regularly and the failed electrode should be replaced in time.

[0052] S200: Acquiring second SOC data of the all-vanadium liquid flow battery to be tested by monitoring the electrolyte valence concentration;

[0053] S201: Potential monitoring includes installing a reference electrode and a working electrode at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank of the all-vanadium liquid flow battery, respectively, and monitoring the changes of the positive electrode potential and the negative electrode potential in real time through a monitoring system.

[0054] S203: Monitoring of electrolyte valence concentration includes installing micro-injection controllers at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank of the all-vanadium liquid flow battery, injecting electrolyte into the liquid collection bottle through the micro-injection controller, and obtaining the valence concentration of the positive and negative electrode electrolytes through ultraviolet visible spectrophotometer or potentiometric titrator testing.

[0055] In the embodiment of the present application, the second SOC data includes the SOC obtained by monitoring the electrolyte valence concentration. 正',n and SOC 负',n The electrolyte valence concentration monitoring is achieved by installing micro-injection controllers at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank of the all-vanadium redox flow battery.

[0056] Specifically, the installation of the micro-injection controller needs to consider the following factors: Installation location: It should be selected at a location where the electrolyte flow is stable to avoid the influence of bubbles and eddy currents; Sealing performance: Ensure that there is no leakage at the installation point to prevent electrolyte volatilization and air entry; Sampling volume: It can be accurately controlled within the range of 0.01-5mL; Sampling frequency: It can be adjusted according to actual needs, generally once every 1-24 hours; Material requirements: Use corrosion-resistant materials, such as Teflon, polytetrafluoroethylene, etc.

[0057] In an optional embodiment, the micro-injection controller can adopt different control methods: solenoid valve control: controlling the sampling volume by switching the solenoid valve; stepper motor control: using a stepper motor to accurately control the sampling volume; peristaltic pump control: using a peristaltic pump to achieve continuous sampling; pneumatic control: using compressed air to drive sampling; hybrid control: combining multiple control methods to improve sampling accuracy.

[0058] It should be noted that the determination methods of electrolyte valence concentration mainly include:

[0059] UV-visible spectrophotometry: select an appropriate measurement wavelength, generally in the range of 400-800nm; establish a standard curve to ensure a good linear relationship; control the sample dilution factor to ensure that the measurement is within the linear range; calibrate the instrument regularly to ensure measurement accuracy; consider the impact of temperature on the measurement results.

[0060] Potentiometric titration: select a suitable titrant, such as potassium permanganate solution; control the titration speed to ensure sufficient reaction; consider the influence of coexisting ions; and calibrate the titrant concentration regularly.

[0061] S300: obtaining a correction coefficient of the all-vanadium liquid flow battery to be tested during potential monitoring according to the first SOC data and the second SOC data;

[0062] S301: Obtaining a correction coefficient according to the first SOC data and the second SOC data includes:

[0063] Calculate the positive electrode correction factor κpositive = SOC 正'，n / SOC 正，n ;

[0064] Calculate the negative electrode correction factor κ negative = SOC 负'，n / SOC 负，n .

[0065] In the embodiment of the present application, the correction coefficient needs to be calculated for the positive electrode and the negative electrode respectively. 正',n With SOC 正，n The negative electrode correction factor κ is obtained by SOC 负',n With SOC 负，n In the actual calculation process, in order to ensure the accuracy of the calculation results, the system will pre-process the collected data, including outlier detection, data smoothing and other operations.

[0066] In an optional embodiment, the correction coefficient can also be calculated by weighted average method. This method comprehensively considers the SOC data of multiple time points by setting different weight coefficients. Specifically, the system first obtains the SOC data of multiple consecutive time points, and then assigns weight coefficients according to factors such as the timeliness and reliability of the data. For example, a larger weight is given to data with a closer time, and a smaller weight is given to data with a farther time. In this way, the impact of a single measurement error on the correction coefficient can be reduced.

[0067] In addition, the correction coefficient can also be calculated using the sliding window method. This method sets a fixed-size time window and dynamically calculates the average correction coefficient of the data in the window. As time goes by, the window continues to slide forward to ensure that the correction coefficient can reflect changes in the battery status in a timely manner. For example, if the window size is set to 2 hours, the system will calculate the average correction coefficient of all valid data in the past 2 hours in real time as the correction coefficient at the current moment.

[0068] It should be noted that temperature is an important influencing factor in the determination of the correction coefficient. Temperature changes will affect the physical and chemical properties of the electrolyte, such as conductivity and ion mobility, and thus affect the potential measurement results. To this end, this application has established a special temperature compensation model. The model monitors the temperature changes of the battery system in real time, analyzes the relationship between temperature and correction coefficient, and establishes a corresponding mathematical model. In actual applications, the system will automatically adjust the correction coefficient according to the current temperature to eliminate the impact of temperature changes.

[0069] At the same time, the system operating pressure will also affect the correction factor. Pressure changes will affect the flow state and ion distribution of the electrolyte, thereby affecting the accuracy of potential measurement. This application installs a pressure sensor to monitor the system operating pressure in real time and analyzes the influence of pressure fluctuations on the correction factor. On this basis, a pressure compensation model is established, which can automatically adjust the correction factor according to pressure changes to ensure the accuracy of the measurement results.

[0070] Changes in the total concentration of the electrolyte will also affect the accuracy of the correction factor. During the long-term operation of the battery, the total concentration of the electrolyte will change due to factors such as the migration of water molecules and the volatilization of the electrolyte. To this end, this application specifically designs a concentration monitoring module to analyze the impact of concentration changes on the correction factor by regularly measuring the total concentration of the electrolyte. Based on the analysis results, the system establishes a concentration compensation model that can automatically adjust the correction factor according to concentration changes.

[0071] S400: Correcting the third SOC data of the all-vanadium liquid flow battery to be detected during the potential monitoring process according to the correction coefficient.

[0072] S401: Correcting the third SOC data according to the correction coefficient includes:

[0073] Calculate the actual SOC of the positive electrode: SOC 正，实 =κpositive×SOC 正 ;

[0074] Calculate the actual SOC of the negative electrode: SOC 负，实 =κ negative × SOC 负 .

[0075] S402: The correction coefficient is determined at a frequency of 0 to 10 days.

[0076] In the embodiment of the present application, the correction of SOC data is performed for the positive electrode and the negative electrode respectively. For the positive electrode, the system uses κ positive and SOC 正 The actual SOC value (SOC 正，实) ; For the negative electrode, the system uses the product of κ negative and SOC negative to obtain the actual SOC value (SOC 负，实) This correction method can effectively compensate for the system error in the potential monitoring process and improve the accuracy of SOC estimation.

[0077] In an optional embodiment, the system can also adopt an adaptive correction method. This method not only considers the correction coefficient, but also comprehensively considers multiple influencing factors such as temperature, pressure, concentration, etc. The system establishes a mathematical model to analyze the influence of various factors on SOC measurement, and then dynamically adjusts the correction parameters according to real-time monitoring data. This method can better adapt to changes in the battery operating environment and improve the correction effect.

[0078] Specifically, the adaptive correction method first needs to establish a mathematical model for SOC measurement. This model represents SOC as a function of correction coefficient, temperature, pressure, concentration and other parameters. Through the fitting and analysis of a large amount of experimental data, the influence weight of each parameter is determined. In actual application, the system dynamically calculates the corrected SOC value based on the various parameters monitored in real time. If the correction effect is found to be unsatisfactory, the system will automatically adjust the model parameters to optimize the correction effect.

[0079] At the same time, this application has also developed a multi-factor joint correction method. This method takes into account long-term influencing factors such as battery aging and number of cycles. The system records the battery's usage history and analyzes the impact of these factors on SOC measurement accuracy. For example, as the number of battery cycles increases, the electrode material may age, causing changes in the potential response characteristics. The system will automatically adjust the correction strategy based on these changes to ensure measurement accuracy during long-term use.

[0080] It should be noted that the correction method of the present application also includes a complete data management mechanism. The system will record the original measurement data, correction parameters, correction results and other information in real time, and establish a special database for storage. These data are not only used for real-time monitoring and analysis, but also for system performance evaluation and optimization. By analyzing historical data, the system can discover potential problems and adjust the correction strategy in time. For example, if it is found that the correction effect of a certain time period is not ideal, the system will automatically analyze the cause and provide optimization suggestions.

[0081] In addition, this application also establishes a quality evaluation system for the correction results. The system comprehensively evaluates the correction effect by setting multiple evaluation indicators, such as the error change before and after the correction, the stability of the correction result, etc. If it is found that the correction result does not meet the requirements, the system will start the self-diagnosis program to check whether there are problems in each link. At the same time, the system will also generate a detailed evaluation report to provide a basis for subsequent optimization.

[0082] Furthermore, this embodiment also provides a dual monitoring and correction system for SOC of an all-vanadium liquid flow battery, comprising:

[0083] A potential monitoring module, used for obtaining first SOC data of the all-vanadium liquid flow battery to be tested;

[0084] An electrolyte concentration monitoring module, used to obtain the second SOC data of the all-vanadium liquid flow battery to be tested;

[0085] A correction coefficient calculation module, used to obtain a correction coefficient of the all-vanadium liquid flow battery to be tested during the potential monitoring process according to the first SOC data and the second SOC data;

[0086] The SOC correction module is used to correct the third SOC data of the all-vanadium liquid flow battery to be detected during the potential monitoring process according to the correction coefficient.

[0087] In summary, by combining potential monitoring and electrolyte valence concentration monitoring, dual verification of SOC is achieved. This dual monitoring method overcomes the defect that single potential monitoring is affected by hydrogen ion concentration, and at the same time solves the problem that single electrolyte concentration monitoring cannot be performed in real time online. Ultimately, the accuracy and reliability of SOC monitoring are improved.

[0088] (1) Potential monitoring steps:

[0089] By installing the reference electrode and working electrode at the outlet of the liquid storage tank, real-time online monitoring of the potential is achieved. Since the electrode is installed at the outlet, the fluidity and representativeness of the electrolyte at the monitoring point are guaranteed, and the accuracy of the monitoring data is improved. This installation position design avoids the influence of the dead zone of the electrolyte, making the measurement results more reliable.

[0090] (2) Electrolyte valence concentration monitoring steps:

[0091] By using a micro-injection controller for sampling, only a very small amount of sample (0.01-5mL) is needed to complete the test, significantly reducing the impact of sampling on battery capacity. At the same time, the use of a closed sampling system avoids the risk of impurities entering the electrolyte during the test and ensures the purity of the battery system.

[0092] (3) Correction coefficient calculation steps:

[0093] By establishing the mathematical relationship of the correction coefficient κ (SOC' / SOC), the offline monitoring results are cleverly associated with the online monitoring data. This association method does not require a complex mathematical model, is simple to calculate and easy to implement, and provides convenience for practical applications.

[0094] (4) SOC correction steps:

[0095] By applying the correction coefficient to the real-time monitoring data, the systematic error of the potential method is compensated while maintaining the advantages of online monitoring. This correction method not only ensures the real-time nature of monitoring, but also improves the accuracy of the data.

[0096] (1) The 0-10-day correction frequency design ensures the timeliness of corrections while avoiding the interference caused by too frequent sampling, thus achieving the best balance between correction frequency and actual needs.

[0097] (2) The design of separately correcting the positive and negative electrodes takes into account the problem of inconsistent states of the positive and negative electrodes during long-term cycling, effectively improving the pertinence and accuracy of the correction.

[0098] Example 2

[0099] Reference Figure 2 - Figure 4 , which is the second embodiment of the present invention.

[0100] Based on the positive and negative oxidation potential monitoring at a certain moment, the charge and discharge state SOC of the battery at a certain moment is obtained 正，n , SOC 负，n Then, according to the electrolyte valence concentration at the same time, SOC is obtained. 正’，n , SOC 负’，n , SOC calculated using electrolyte concentration 正’ , SOC 负’ SOC obtained by potential monitoring 正 , SOC 负 Modifications are made, and the correction coefficients are κ positive = SOC 正’，n / SOC 正，n , κ negative = SOC 负’，n / SOC 负，nThe actual SOC of the positive and negative electrodes of the battery are SOC 正，实 =κpositive×SOC 正 , SOC 负，实 =κpositive×SOCnegative.

[0101] For the all-vanadium flow battery to be tested, the first all-vanadium flow battery SOC is obtained based on the positive and negative oxidation potential monitoring at a certain moment, and the second all-vanadium flow battery SOC is obtained based on the electrolyte valence concentration monitoring at the same moment. The first all-vanadium flow battery SOC includes the charge and discharge state SOC at a certain moment. 正，n , SOC 负，n The second all-vanadium flow battery SOC includes SOC 正’，n , SOC 负’，n .

[0102] Potential monitoring: A reference electrode (4) and a working electrode (6) are installed at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank (1) of the all-vanadium liquid flow battery to form a working electrode pair. The reference electrode (4) and the working electrode (6) are connected to the monitoring system (5). The detection system (5) monitors the changes in the positive electrode potential and the negative electrode potential of the all-vanadium liquid flow battery in real time through the reference electrode (4) and the working electrode (6) connected thereto. The battery charge and discharge state SOC can be obtained from the obtained test potential according to the relevant potential calculation formula. 正 , SOC 负 .

[0103] Combination Figure 4 , the process of potential monitoring is as follows:

[0104] A reference electrode 4 and a working electrode 6 are installed at the outlet of the positive electrode storage tank and the outlet 1 of the negative electrode storage tank of the all-vanadium liquid flow battery to form a working electrode pair, wherein the reference electrode 4 is a mercurous sulfate electrode, and the working electrode 6 is a platinum sheet electrode or a platinum wire electrode to form a working electrode pair, and a monitoring system 5 is used to monitor the changes in the positive electrode potential and the negative electrode potential of the all-vanadium liquid flow battery in real time. During the charge and discharge process, the positive and negative electrode reactions of the all-vanadium liquid flow battery are:

[0105] Positive electrode pair: V(V) / V(IV)

[0106]

[0107] Negative electrode pair: V(Ⅲ) / V(Ⅱ)

[0108]

[0109] Positive electrode monitoring potential:

[0110]

[0111] Negative electrode monitoring potential:

[0112]

[0113] In the formula, E 正 、E 负 ——Test positive and negative potential, V;

[0114] ——Electrode potential of mercuric sulfate when tetravalent vanadium is oxidized to pentavalent vanadium, divalent vanadium is oxidized to trivalent vanadium, V;

[0115] ——Standard electrode potential of the oxidation of tetravalent vanadium to pentavalent vanadium and the oxidation of divalent vanadium to trivalent vanadium, V;

[0116] ——Concentrations of pentavalent vanadium, tetravalent vanadium, trivalent vanadium, and divalent vanadium, moL / L; SOC 正 , SOC 负 ——The battery charging and discharging status is obtained by the potential monitoring method, %.

[0117] AB, C, D——are constants, fixed values.

[0118] EHg / Hg2SO4 can be considered constant, and A, B, C, and D are fixed values. In this way, SOC can be obtained by testing the change in potential. 正 and SOC 负 .

[0119] At a certain moment of charge and discharge, the SOC of the battery at a certain moment is obtained by the potential monitoring method. 正，n , SOC 负，n ,Right now:

[0120]

[0121]

[0122] Monitoring of vanadium ion concentration: A micro-injection controller (2) is installed at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank (1) of the all-vanadium liquid flow battery, and the micro-injection controller (2) is connected to the liquid collection bottle (3). Electrolyte 0.01-5mL is injected into the liquid collection bottle (3) from the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank through the micro-injection controller (2) at regular intervals, and then tested by a UV-visible spectrophotometer or a potentiometric titrator to obtain the valence state concentration of the positive and negative electrode electrolytes. According to the valence state concentration of the electrolyte, the charge and discharge state SOC of the positive and negative electrodes of the battery is obtained. 正’ , SOC 负’ .

[0123] Combination Figure 4 , the process of monitoring the electrolyte valence concentration is as follows:

[0124] A micro-injection controller 2 is installed at the liquid outlet of the positive electrode storage tank and the liquid outlet 1 of the negative electrode storage tank, respectively, and the electrolyte for monitoring is taken from the positive electrode storage tank or the negative electrode storage tank through the micro-injection controller 2 to the liquid collection bottle 3 at a fixed time, and an appropriate amount of liquid is taken from the liquid collection bottle 3, and the valence state concentration of the vanadium ion in the electrolyte is measured by potentiometric titration or spectrophotometry to obtain the concentration of vanadium ions in different valence states. Depend on Calculation of SOC of vanadium battery by concentration ratio 正’ and SOC 负’ ,Right now:

[0125]

[0126]

[0127] In the formula, ——Concentrations of pentavalent vanadium, tetravalent vanadium, trivalent vanadium, and divalent vanadium, moL / L;

[0128] SOC 正’ , SOC 负’ ——The battery charging and discharging status is obtained by monitoring the ion concentration, %.

[0129] At the same time of monitoring at the same potential, the electrolyte for monitoring is taken from the liquid outlet 1 of the positive and negative electrode storage tanks through the micro-injection controller 2 to the liquid collection bottle 3, and the vanadium ion valence concentration of the electrolyte at this time is measured by potentiometric titration or spectrophotometry to obtain the vanadium ion concentration of different valence states. but:

[0130]

[0131]

[0132] Determination of correction coefficient: At the same time, the SOC of the battery at a certain moment is obtained by the potential monitoring method. 正，n , SOC 负，n At the same time, open the micro-injection controller (2) on the positive and negative electrode storage tanks to take 0.01-5mL of positive and negative electrode electrolytes respectively, and test them with a UV-visible spectrophotometer or potentiometric titrator to obtain the battery positive and negative electrode charge and discharge state SOC 正’，n , SOC 负’，n , the correction coefficients for the positive and negative electrodes are κpositive = SOCpositive', n / SOCpositive, n, κnegative = SOCnegative', n / SOC 负，n .

[0133] Actual SOC: The actual SOC of the positive and negative electrodes of the battery are SOC正 , real = κ positive × SOC 正 , SOC 负 , real = κ positive × SOC 负 .

[0134] According to the SOC of the first all-vanadium redox flow battery and the SOC of the second all-vanadium redox flow battery, a correction coefficient of the all-vanadium redox flow battery to be detected during the potential monitoring process is obtained.

[0135] Among them, according to the ratio between the SOC of the first all-vanadium redox flow battery and the SOC of the second all-vanadium redox flow battery, a correction coefficient is obtained. The correction coefficient is as follows:

[0136] κ 正 =SOC 正'，n / SOC 正，n

[0137] κ 负 =SOC 负'，n / SOC 负，n

[0138] According to the correction coefficient, the third all-vanadium liquid flow battery SOC of the all-vanadium liquid flow battery to be detected during the potential monitoring process is corrected. Wherein, the monitoring time of the third all-vanadium liquid flow battery SOC is after a certain moment. The third all-vanadium liquid flow battery SOC includes SOC 正，实 , SOC 负，实 .

[0139] The correction process is as follows:

[0140] SOC 正，实 =κ 正 ×SOC 正

[0141] SOC 负，实 =κ 正 ×SOC 负

[0142] It should be noted that during the operation of the flow battery, the migration of active ions and water molecules at the positive and negative electrodes will occur, and the valence concentration will be constantly changing, so the valence concentration of the electrolyte needs to be monitored after a period of time.

[0143] Therefore, even if the volume changes of the positive and negative electrodes are not obvious, due to the migration of active ions, it is still necessary to re-correct them to ensure that the correction factor can adapt to the changes in the operating environment of the all-vanadium liquid flow battery.

[0144] Based on this, each time a liquid extraction test is performed, a correction coefficient is determined. That is, each time the electrolyte valence concentration is monitored, the correction coefficient is updated, or when the correction coefficient is needed, the electrolyte valence concentration needs to be monitored. Among them, the updating frequency of the correction coefficient can be set by technicians in this field according to actual needs. For example, the frequency of determining the correction coefficient can be 0 to 10 days, that is, the correction coefficient is updated every 10 days.

[0145] In addition, only the SOC obtained by potential monitoring and the SOC obtained by UV and spectrophotometry at the same time are meaningful for comparison. As for the specific time selected, since different times are different in the valence concentration of active ions, it will not have any effect on the correction coefficient. Therefore, as long as the potential monitoring and electrolyte valence concentration monitoring are ensured at the same time, the correction coefficient in this application can be calculated.

[0146] Key points and technical protection points of the present invention:

[0147] The working principle of all-vanadium flow battery is as follows:

[0148] All-vanadium liquid flow batteries are different from ordinary batteries in that their active materials are contained in solid electrodes. The positive and negative active materials are mainly present in the electrolyte, which is respectively stored in two liquid storage tanks. When working, the liquid pump circulates through the battery. The positive and negative electrolytes in the battery are separated by an ion exchange membrane. All-vanadium liquid flow batteries use vanadium ion solution as the positive and negative active materials. The positive electrode is a V(IV) / V(V) electrode pair, and the negative electrode is a V(III) / V(II) electrode pair. The solvent is dilute sulfuric acid. The positive electrode electrolyte is a sulfuric acid solution of V(V) and V(IV), and the negative electrode electrolyte is a sulfuric acid solution of V(III) and V(II). The electrodes are composed of active materials and current collectors, and the standard potential difference between the pairs is about 1.25V. The voltage and current efficiency can reach more than 90%, and the total energy efficiency can also reach more than 90%.

[0149] Based on this, the inventive concept of this application is explained as follows:

[0150] Since potential monitoring is usually adopted for real-time online monitoring, the applicant takes into account that during the test process, the actual monitoring potential is affected by factors such as ion concentration, temperature, reference electrode, etc., and the error is relatively large.

[0151] That is, during the charge and discharge process of the all-vanadium liquid flow battery, the valence state of the vanadium ions in the positive and negative electrodes is constantly changing. In addition, due to the presence of a small amount of side reactions, water penetration and active ion penetration during the charge and discharge process, the battery's SOC will be affected.

[0152] Therefore, it is necessary to monitor the concentration of active ions of different valence states in the positive and negative electrodes of the battery, that is, electrolyte concentration monitoring. The SOC accuracy of electrolyte concentration monitoring is also relatively higher. However, electrolyte concentration monitoring cannot achieve online monitoring.

[0153] Based on this, the applicant came up with a solution to compensate for the defect that the electrolyte concentration cannot be monitored online in real time. By using the SOC ratio of the two at the same time as the correction coefficient, the following can be achieved: Correction coefficient (SOC 正’，n1 / SOC 正，n1 ) multiplied by SOC 正，n2 Obviously, the product result is equivalent to directly monitoring the electrolyte concentration, and the obtained SOC 正’，n2 .

[0154] Example 3

[0155] This embodiment also provides a computer device, which is applicable to a method for dual monitoring and correction of SOC of an all-vanadium liquid flow battery, and includes a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement a forced oscillation detection and positioning method for a distribution network as proposed in the above embodiment.

[0156] This embodiment further provides a storage medium on which a computer program is stored. When the program is executed by a processor, a forced oscillation detection and positioning method for a distribution network is implemented as proposed in the above embodiment.

[0157] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0158] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0159] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0160] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0161] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0162] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A dual monitoring and correction method for SOC of an all-vanadium liquid flow battery, characterized in that: Including, obtaining first SOC data of the all-vanadium liquid flow battery to be tested through potential monitoring; Acquiring second SOC data of the all-vanadium redox flow battery to be tested by monitoring the electrolyte valence concentration; According to the first SOC data and the second SOC data, a correction coefficient of the all-vanadium liquid flow battery to be tested during potential monitoring is obtained; According to the correction coefficient, the third SOC data of the all-vanadium redox flow battery to be tested during the potential monitoring process is corrected.

2. The all-vanadium liquid flow battery SOC dual monitoring and correction method according to claim 1, characterized in that: The first SOC data includes: The positive electrode charge and discharge state SOC obtained by potential monitoring 正，n and negative electrode charge and discharge state SOC 负，n ; The second SOC data includes the SOC obtained by monitoring the electrolyte valence concentration 正'，n and SOC 负 ' ，n .

3. The all-vanadium liquid flow battery SOC dual monitoring and correction method according to claim 2, characterized in that: The potential monitoring includes installing a reference electrode and a working electrode at the outlet of the positive electrode storage tank and the outlet of the negative electrode storage tank of the all-vanadium liquid flow battery respectively, and monitoring the changes of the positive electrode potential and the negative electrode potential in real time through a monitoring system.

4. The all-vanadium liquid flow battery SOC dual monitoring and correction method according to claim 3, characterized in that: The electrolyte valence concentration monitoring includes installing micro-injection controllers at the liquid outlet of the positive electrode storage tank and the liquid outlet of the negative electrode storage tank of the all-vanadium liquid flow battery, injecting electrolyte into the liquid collection bottle through the micro-injection controller, and obtaining the positive and negative electrode electrolyte valence concentrations through ultraviolet visible spectrophotometer or potentiometric titrator testing.

5. The all-vanadium liquid flow battery SOC dual monitoring and correction method according to claim 4, characterized in that: Obtaining a correction coefficient according to the first SOC data and the second SOC data includes: Calculate the positive electrode correction factor κpositive = SOC 正'，n / SOC 正，n ; Calculate the negative electrode correction factor κ negative = SOC 负'，n / SOC 负，n .

6. The all-vanadium liquid flow battery SOC dual monitoring and correction method according to claim 5, characterized in that: Correcting the third SOC data according to the correction coefficient includes: Calculate the actual SOC of the positive electrode: SOC 正，实 =κpositive×SOC 正 ; Calculate the actual SOC of the negative electrode: SOC 负，实 =κ negative × SOC 负 .

7. The all-vanadium liquid flow battery SOC dual monitoring and correction method according to claim 6, characterized in that: The correction coefficient is determined at a frequency of 0 to 10 days.

8. A dual monitoring and correction system for SOC of an all-vanadium redox flow battery, based on the dual monitoring and correction method for SOC of an all-vanadium redox flow battery according to any one of claims 1 to 7, characterized in that: It also includes a potential monitoring module for obtaining first SOC data of the all-vanadium liquid flow battery to be tested; An electrolyte concentration monitoring module, used for obtaining the second SOC data of the all-vanadium liquid flow battery to be tested; A correction coefficient calculation module, used for obtaining a correction coefficient of the all-vanadium liquid flow battery to be tested during potential monitoring according to the first SOC data and the second SOC data; The SOC correction module is used to correct the third SOC data of the all-vanadium liquid flow battery to be detected during the potential monitoring process according to the correction coefficient.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the all-vanadium liquid flow battery SOC dual monitoring and correction method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the all-vanadium liquid flow battery SOC dual monitoring and correction method according to any one of claims 1 to 7 are implemented.

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