Method for improving energy storage efficiency of flow battery based on high-frequency isolation technology

Abstract

The present invention discloses a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology, belonging to the field of new generation information technology. The method includes the following steps: monitoring the charging state data of the flow battery and analyzing to obtain the charging state index of the flow battery; adjusting the charging mode of the flow battery according to the charging state index of the flow battery, where the charging mode of the flow battery includes a constant current charging mode and a constant voltage charging mode; collecting the performance data of the flow battery, processing to obtain a performance evaluation index of the flow battery, matching a constant current reference current value and a constant voltage reference voltage value according to the performance evaluation index of the flow battery, and adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery. By adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery, the present invention achieves precise control of the charging current and charging voltage of the flow battery.

Description

Technical Field

[0001] The present invention relates to the field of new generation information technology, and particularly to a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology. Background Art

[0002] With the advancement of the global energy transition, energy storage technology has become increasingly important and is regarded as one of the key technologies for achieving the energy transition. In order to meet the intermittent output of renewable energy, flow batteries have become an ideal choice for long-duration energy storage due to their long lifespan, high safety, and flexibility.

[0003] The existing flow battery energy storage system realizes the storage and release of energy through the charge and discharge process of the flow battery. The positive and negative electrolyte solutions of the flow battery are respectively contained in two storage tanks, and a liquid delivery pump is used to circulate the electrolyte solution through the battery. Inside the stack, the positive and negative electrolyte solutions are separated by an ion exchange membrane, and the battery is externally connected to a load and a power source.

[0004] For example, the flow battery and flow battery stack disclosed in the patent application with the publication number: CN103413960A include: a first bipolar plate, a second bipolar plate, two flow frames, two electrodes, and an ion exchange membrane. The ion exchange membrane is clamped between the two electrodes, and the two electrodes are respectively embedded in the cavities of the two flow frames. A reaction space is formed between the current collecting surfaces of the first bipolar plate and the second bipolar plate that face each other. The current collecting surface of the first bipolar plate includes a first recess, and the current collecting surface of the second bipolar plate includes a first protrusion that cooperates with the first recess. The two electrodes and the ion exchange membrane form a concavo-convex structure in adaptation to the shape of the reaction space between the first bipolar plate and the second bipolar plate. Since the electrodes and the ion exchange membrane form a concavo-convex structure, the area of the electrodes and the ion exchange membrane is increased, the internal resistance of the flow battery is reduced, and the current density of the flow battery is increased, so as to achieve the purpose of improving the efficiency and power of the flow battery.

[0005] For example, a flow battery system with high voltage efficiency disclosed in the invention patent announcement with the announcement number: CN114665135B specifically relates to a flow battery system with high voltage efficiency to assist in the design, evaluation, and performance optimization of flow batteries. On the one hand, by detecting the method of membrane fouling, it is tested that the change in battery resistance during the charge and discharge process of the battery is less than 50%, and it is judged that the battery does not have membrane fouling. If it exceeds this range, it is judged that membrane fouling occurs. To judge whether there is a need to replace the battery or the membrane to cope with long endurance or other demanding battery application scenarios. On the other hand, it also provides a 4-hydroxy-2,2,6,6-tetramethylpiperidine oxide / zinc flow battery system with anti-membrane fouling. A polyvinylidene fluoride porous membrane without membrane fouling phenomenon is used in the flow battery, which has better battery cycling performance, and reduces the cost of the flow battery from both the positive active material and the membrane aspects, which will further promote the development of flow batteries.

[0006] However, in the process of implementing the inventive technical solution in the embodiments of the present application, it is found that the above technologies have at least the following technical problems:

[0007] In the prior art, when a flow battery is charged, due to the instability of the charging current and charging voltage of the flow battery, the potential difference inside the flow battery fluctuates, affecting the electrochemical reaction efficiency of the flow battery, resulting in the problem of low energy storage efficiency of the flow battery. Summary of the Invention

[0008] The embodiments of the present application provide a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology, which solves the problem in the prior art that when a flow battery is charged, due to the instability of the charging current and charging voltage of the flow battery, the potential difference inside the flow battery fluctuates, affecting the electrochemical reaction efficiency of the flow battery, resulting in the problem of low energy storage efficiency of the flow battery, and realizes real-time adjustment of the charging current and charging voltage of the flow battery according to the charging state of the flow battery, improving the energy storage efficiency of the flow battery.

[0009] The embodiments of the present application provide a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology, including the following steps: monitoring the charging state data of the flow battery, and analyzing to obtain the charging state index of the flow battery; adjusting the charging mode of the flow battery according to the charging state index of the flow battery, where the charging mode of the flow battery includes a constant current charging mode and a constant voltage charging mode; collecting the performance data of the flow battery, processing to obtain the performance evaluation index of the flow battery, matching to obtain the constant current reference current value and the constant voltage reference voltage value according to the performance evaluation index of the flow battery, and adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery.

[0010] Further, the step of monitoring the charging state data of the flow battery and analyzing to obtain the charging state index of the flow battery includes: the charging state data of the flow battery includes the electrolyte concentration, current efficiency, and charging time of the flow battery; comprehensively analyzing according to the electrolyte concentration, current efficiency, and charging time of the flow battery to obtain the charging state index of the flow battery.

[0011] Further, the specific calculation formula of the charging state index of the flow battery is:

[0012] ;

[0013] In the formula, ξ represents the charging state index of the flow battery, α represents the weight factor of the charging state index of the flow battery corresponding to the electrolyte concentration, β represents the weight factor of the charging state index of the flow battery corresponding to the current efficiency, γ represents the weight factor of the charging state index of the flow battery corresponding to the charging time, Indicates the electrolyte concentration of the current flow battery, Indicates the threshold value of the electrolyte concentration range of the flow battery when it is close to full charge, Indicates the current efficiency of the current flow battery, Indicates the rated current efficiency of the flow battery, Indicates the charging time of the current flow battery, Indicates the maximum charging time of the flow battery.

[0014] Further, the specific process of adjusting the charging mode of the flow battery according to the charging state index of the flow battery includes: first, obtaining the preset threshold value of the charging state index of the flow battery from the flow battery database; comparing the charging state index of the flow battery with the threshold value of the charging state index of the flow battery. If the charging state index of the flow battery is less than the threshold value of the charging state index of the flow battery, the charging mode of the flow battery is adjusted to the constant current charging mode. If the charging state index of the flow battery is greater than or equal to the threshold value of the charging state index of the flow battery, the charging mode of the flow battery is switched to the constant voltage charging mode.

[0015] Further, the steps of collecting the performance data of the flow battery and obtaining the performance evaluation index of the flow battery through processing include: obtaining the cumulative working duration and the rated working power of the flow battery and recording them as the performance data of the flow battery; comprehensively analyzing the performance data of the flow battery to obtain the performance evaluation index of the flow battery.

[0016] Further, the steps of adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery include: obtaining the range of the constant current reference current value of the constant current charging mode and the range of the constant voltage reference voltage value of the constant voltage charging mode according to the performance evaluation index of the flow battery; adjusting the charging current of the flow battery once according to the range of the constant current reference current value in the constant current charging mode, and adjusting the charging voltage of the flow battery once according to the range of the constant voltage reference voltage value in the constant voltage charging mode; after the first adjustment of the charging state, monitoring the temperature data of the flow battery and adjusting the charging current of the flow battery a second time according to the temperature data of the flow battery.

[0017] Further, the steps of obtaining the constant current reference current value range in the constant current charging mode and the constant voltage reference voltage value range in the constant voltage charging mode according to the flow battery performance evaluation index include: matching the flow battery performance evaluation index with the constant current reference current value and the constant voltage reference voltage value corresponding to each flow battery performance evaluation index interval stored in the flow battery database to obtain the constant current reference current value and the constant voltage reference voltage value of the flow battery; obtaining the preset allowable deviation charging current and allowable deviation charging voltage from the flow battery database; performing subtraction and summation operations on the constant current reference current value and the allowable deviation charging current respectively, and marking the difference result and the summation result as the reference current lower limit and the reference current upper limit respectively, and marking the range between the reference current lower limit and the reference current upper limit as the constant current reference current value range; performing subtraction and summation operations on the constant voltage reference voltage value and the allowable deviation charging voltage respectively, and marking the difference result and the summation result as the reference voltage lower limit and the reference voltage upper limit respectively, and marking the range between the reference voltage lower limit and the reference voltage upper limit as the constant voltage reference voltage value range.

[0018] Further, the steps of performing a first adjustment on the charging current of the flow battery according to the constant current reference current value range in the constant current charging mode include: when the charging mode of the flow battery is the constant current charging mode, monitoring the charging current of the flow battery, and marking the absolute value of the difference between the charging current of the flow battery and the constant current reference current value as the current parameter to be adjusted; if the charging current of the flow battery is greater than or equal to the reference current lower limit and less than or equal to the reference current upper limit, maintaining the charging state of the flow battery; if the charging current of the flow battery is greater than the reference current upper limit, reducing the charging current of the flow battery according to the current parameter to be adjusted; if the charging current of the flow battery is less than the reference current lower limit, increasing the charging current of the flow battery according to the current parameter to be adjusted.

[0019] Further, the steps of performing a second adjustment on the charging current of the flow battery according to the temperature data of the flow battery include: monitoring the temperature and the temperature change rate of the flow battery, which are recorded as the temperature data of the flow battery; processing the temperature data of the flow battery to obtain the flow battery temperature anomaly evaluation value; obtaining the preset temperature anomaly evaluation threshold from the flow battery database, and when the flow battery temperature anomaly evaluation value is higher than the preset temperature anomaly evaluation threshold, matching the current correction value according to the flow battery temperature anomaly evaluation value, and adjusting the charging current according to the current correction value.

[0020] Further, the calculation formula for the flow battery temperature anomaly evaluation value is:

[0021] ;

[0022] In the formula, δ represents the abnormal evaluation value of the flow battery temperature, μ represents the weight factor of the abnormal evaluation value of the flow battery temperature corresponding to the temperature of the flow battery, and λ represents the weight factor of the abnormal evaluation value of the flow battery temperature corresponding to the temperature change rate. represents the critical temperature of the flow battery. represents the current temperature of the flow battery. represents the critical temperature change rate of the flow battery. represents the temperature change rate of the current flow battery.

[0023] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0024] 1. According to the charging state of the flow battery, the present invention adjusts the charging current and charging voltage of the flow battery in real time, reduces the loss of active substances inside the flow battery, reduces energy loss, and thus improves the energy storage efficiency of the flow battery.

[0025] 2. By adjusting the flow battery once according to the optimal constant current reference current value range and the optimal constant voltage reference voltage value range, the present invention avoids overcharging of the battery, and thus improves the safety of the charging process of the flow battery.

[0026] 3. By adjusting the charging mode of the flow battery according to the flow battery charging state index obtained from the analysis of the charging state data of the flow battery, the present invention improves the charging efficiency and shortens the charging time of the flow battery. Description of the Drawings

[0027] Figure 1 is a flowchart of a method for improving the energy storage efficiency of a flow battery based on a high-frequency isolation technology provided by an embodiment of the present application;

[0028] Figure 2 is a change diagram of the abnormal evaluation value of the flow battery temperature of the method for improving the energy storage efficiency of a flow battery based on a high-frequency isolation technology provided by an embodiment of the present application. Detailed Embodiments

[0029] Embodiments of the present application provide a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology, which solves the problem in the prior art that when the flow battery is charged, due to the instability of the charging current and charging voltage of the flow battery, the internal potential difference of the flow battery fluctuates, affecting the electrochemical reaction efficiency of the flow battery and resulting in low energy storage efficiency of the flow battery. By monitoring the charging state data of the flow battery, the charging state index of the flow battery is analyzed, and then according to the charging state index of the flow battery, the charging mode of the flow battery is adjusted. The charging mode of the flow battery includes a constant current charging mode and a constant voltage charging mode. Then, the performance data of the flow battery is collected, and after processing, a performance evaluation index of the flow battery is obtained. According to the performance evaluation index of the flow battery, a constant current reference current value and a constant voltage reference voltage value are matched, and the charging current and charging voltage of the flow battery are adjusted in real time according to the charging mode of the flow battery.

[0030] The technical solution in the embodiments of the present application aims to solve the problem in the prior art that when the flow battery is charged, due to the instability of the charging current and charging voltage of the flow battery, the internal potential difference of the flow battery fluctuates, affecting the electrochemical reaction efficiency of the flow battery and resulting in low energy storage efficiency of the flow battery. The general idea is as follows:

[0031] By monitoring the charging state data of the flow battery, the charging state index of the flow battery is analyzed, and then according to the charging state index of the flow battery, the charging mode of the flow battery is adjusted. The charging mode of the flow battery includes a constant current charging mode and a constant voltage charging mode. Then, the performance data of the flow battery is collected, and after processing, a performance evaluation index of the flow battery is obtained. According to the performance evaluation index of the flow battery, a constant current reference current value and a constant voltage reference voltage value are matched, and the charging current and charging voltage of the flow battery are adjusted in real time according to the charging mode of the flow battery, achieving real-time adjustment of the charging current and charging voltage of the flow battery according to the charging state of the flow battery, and improving the charging efficiency and service life of the flow battery.

[0032] To better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0033] Such as Figure 1As shown in the figure, it is a flowchart of a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology provided by an embodiment of the present application. The method includes the following steps: First, monitor the charging state data of the flow battery, and analyze to obtain the charging state index of the flow battery, which is an important basis for evaluating the current power state of the battery. Then, according to the charging state index of the flow battery, adjust the charging mode of the flow battery. The charging mode of the flow battery includes a constant current charging mode and a constant voltage charging mode. Next, collect the performance data of the flow battery, and obtain the performance evaluation index of the flow battery through processing, which is used to evaluate the health state and performance of the battery. According to the performance evaluation index of the flow battery, match the constant current reference current value and the constant voltage reference voltage value, and adjust the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery.

[0034] In this embodiment, the constant current charging mode is a charging method that controls the charging current of the battery to remain constant during the entire charging process, which can ensure that the battery is charged with a stable current, thereby avoiding the impact of current fluctuations on the battery performance. The constant current charging mode is generally applied to the initial charging stage of the battery and scenarios where rapid power replenishment is required; constant voltage charging refers to a charging method that controls the charging voltage of the battery to maintain a constant value during the entire charging process, which can ensure that the voltage of the battery is stable during charging, thereby protecting the battery from overcharging and other damages. The constant voltage charging mode is usually used in the later stage of battery charging to ensure that the battery will not be damaged due to excessive voltage after being fully charged. In addition, constant voltage charging is also commonly used for the maintenance charging of the battery to maintain the performance and lifespan of the battery. In addition, through the method for improving the energy storage efficiency of the flow battery in this embodiment, not only can it ensure that the battery is charged in the best state, thereby improving the charging efficiency and reducing the charging time, but also it can reduce the stress and damage inside the battery, thereby extending the cycle life and service life of the battery, helping to avoid the occurrence of unsafe situations such as overcharging and over-discharging, and improving the safety of the entire system.

[0035] Further, the steps of monitoring the charging state data of the flow battery and analyzing to obtain the charging state index of the flow battery include: The charging state data of the flow battery includes the electrolyte concentration, current efficiency, and charging time of the flow battery; according to the electrolyte concentration, current efficiency, and charging time of the flow battery, comprehensively analyze to obtain the charging state index of the flow battery.

[0036] In this embodiment, the electrolyte is a key substance for storing and transferring energy in the flow battery. Its concentration directly affects the voltage, capacity, and performance of the battery. Therefore, by monitoring the electrolyte concentration, the energy storage state inside the battery can be understood. In the charging state, as the charge increases, the electrolyte concentration also continuously increases. When the charging is nearly complete, the electrolyte concentration can reach a relatively stable state. The electrolyte concentration can be directly obtained by measuring with an electrolyte analyzer or by using the property that ions move towards the electrodes under the action of an external electric field and generate current on the electrode surface. The conductivity method is used to monitor the electrolyte concentration in real time by measuring the conductivity. The current efficiency reflects the ratio of the actual charge transferred to the theoretical charge transferred during the charging or discharging process of the battery. It is one of the important indicators for evaluating the battery performance and can reflect the energy conversion efficiency inside the battery. During the charging process, the internal chemical reactions and electrolyte state of the flow battery are gradually optimized, and the current efficiency continuously increases. However, at the end of the charging period, the increase in the internal resistance of the flow battery and the limitation of chemical reactions lead to an increase in energy loss and a decrease in the current efficiency. The current efficiency can be obtained by using current sensors and voltage sensors to measure the charging current, charging voltage, discharging current, and discharging voltage in real time, calculating the charging power and discharging power, and obtaining the ratio of the charging power to the discharging power. The charging time refers to the time required from the start of charging to the battery reaching a specific charging state (such as fully charged), which can be directly obtained by timing with a stopwatch. By monitoring the charging time, the charging speed and charging efficiency of the battery can be evaluated. Through the electrolyte concentration, current efficiency, and charging time of the flow battery, the charging state indicators of the flow battery can be comprehensively evaluated. Analyzing the abnormal changes in the charging state data can promptly detect problems with the battery and take measures to avoid the expansion of faults or affecting the normal operation of the system.

[0037] Further, the charging state indicators of the flow battery are specifically calculated as follows:

[0038] ;

[0039] In the formula, ξ represents the charging state indicator of the flow battery, α represents the weight factor of the charging state indicator of the flow battery corresponding to the electrolyte concentration, β represents the weight factor of the charging state indicator of the flow battery corresponding to the current efficiency, γ represents the weight factor of the charging state indicator of the flow battery corresponding to the charging time, represents the current electrolyte concentration of the flow battery, represents the threshold value of the electrolyte concentration range when the flow battery is nearly fully charged, represents the current current efficiency of the flow battery, represents the rated current efficiency of the flow battery, represents the current charging time of the flow battery, represents the maximum charging time of the flow battery.

[0040] In this embodiment, the weight factor of the flow battery charging state index corresponding to the electrolyte concentration is the influence factor corresponding to the electrolyte concentration in the flow battery database, which represents the numerical value of the influence degree of the electrolyte concentration on the flow battery charging state index. When in use, the influence factor corresponding to the electrolyte concentration can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the current flow battery electrolyte concentration and the influence factor corresponding to the pre-set electrolyte concentration in the flow battery database form a mapping set, and the real-time flow battery electrolyte concentration is input into the mapping set to obtain its corresponding influence factor, where the mapping relationship can be one-to-one or many-to-one. In this example, its value range is [0,1]. As the charging progresses, the electrolyte concentration inside the battery will gradually increase, which indicates that the battery is storing more energy. When the electrolyte concentration reaches the threshold of the electrolyte concentration range, it can be stated that the flow battery is close to the fully charged state. By the ratio of the current flow battery electrolyte concentration to the threshold of the electrolyte concentration range when the flow battery is close to being fully charged, the flow battery charging state index can be evaluated from the perspective of the electrolyte; the weight factor of the flow battery charging state index corresponding to the current efficiency is the influence factor corresponding to the current efficiency in the flow battery database, which represents the numerical value of the influence degree of the current efficiency on the flow battery charging state index. When in use, the influence factor corresponding to the current efficiency can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the current flow battery current efficiency and the influence factor corresponding to the pre-set current efficiency in the flow battery database form a mapping set, and the real-time flow battery current efficiency is input into the mapping set to obtain its corresponding influence factor, where the mapping relationship can be one-to-one or many-to-one. In this example, its value range is [0,1]. The higher the current efficiency, the smaller the energy loss during the charging process of the battery, and the higher the charging efficiency. The closer the current flow battery current efficiency is to the rated current efficiency of the flow battery, the higher the charging state index of the flow battery is indicated. By the ratio of the current flow battery current efficiency to the rated current efficiency of the flow battery, the flow battery charging state index can be evaluated from the perspective of the current efficiency; the weight factor of the flow battery charging state index corresponding to the charging time is the influence factor corresponding to the charging time in the flow battery database, which represents the numerical value of the influence degree of the charging time on the flow battery charging state index. When in use, the influence factor corresponding to the charging time can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the current flow battery charging time and the influence factor corresponding to the pre-set charging time in the flow battery database form a mapping set, and the real-time flow battery charging time is input into the mapping set to obtain its corresponding influence factor, where the mapping relationship can be one-to-one or many-to-one.In this example, its value range is [0, 1]. The charging time is also affected by the charging strategy. For example, when the constant current charging mode is adopted, the charging time is mainly determined by the battery capacity and the charging current. When the constant voltage charging mode is adopted, the charging time is more affected by the battery internal resistance and voltage change. Therefore, by the ratio of the current charging time of the flow battery to the maximum charging time of the flow battery, the charging state index of the flow battery can be evaluated from the perspective of the charging time.

[0041] Furthermore, the specific process of adjusting the flow battery charging mode according to the flow battery charging state index includes: first, obtaining the preset flow battery charging state index threshold from the flow battery database; comparing the flow battery charging state index with the flow battery charging state index threshold. If the flow battery charging state index is less than the flow battery charging state index threshold, the flow battery charging mode is adjusted to the constant current charging mode. If the flow battery charging state index is greater than or equal to the flow battery charging state index threshold, the flow battery charging mode is automatically switched to the constant voltage charging mode by controlling the output voltage and output current of the flow battery charging device.

[0042] In this embodiment, by dynamically switching the charging mode according to the actual charging state of the battery, it can ensure that the battery can be charged in the optimal way at different power levels, thereby improving the charging efficiency. The constant voltage charging mode can reduce the risk of overcharging when the battery is nearly full, while the constant current charging mode can quickly supplement the power when the battery power is low. The combined use of these two modes helps to extend the service life of the battery. By realizing the intelligent management of the flow battery charging process, it can reduce battery failures or system abnormalities caused by improper charging, and improve the stability and reliability of the entire system.

[0043] The flow battery database is used to store relevant data for flow battery charging regulation, including: flow battery charging state index, flow battery performance evaluation index, flow battery temperature abnormality evaluation value, etc. The flow battery database can be obtained by using existing public databases or platforms, such as the energy storage database of the National Energy Administration, the energy storage technology database of the International Energy Agency, etc., or by inputting a large amount of flow battery-related data through experiments.

[0044] Furthermore, the steps of collecting flow battery performance data and obtaining the flow battery performance evaluation index through processing include: obtaining the cumulative working duration and rated working power of the flow battery and recording them as flow battery performance data; comprehensively analyzing the flow battery performance data to obtain the flow battery performance evaluation index.

[0045] In this embodiment, the calculation formula of the flow battery performance evaluation index is:

[0046] ;

[0047] In the formula, represents the performance evaluation index of the flow battery, represents the weight factor of the performance evaluation index of the flow battery corresponding to the cumulative working duration of the flow battery, represents the weight factor of the performance evaluation index of the flow battery corresponding to the rated working power, and + = 1, which can be extracted from the flow battery database, represents the influence coefficient of the cumulative working duration on the performance of the flow battery. The magnitude of its value reflects the influence of the cumulative working duration on the battery performance. At the same time, its change situation can reflect the change of the flow battery performance with the increase of the flow battery usage time, can be adjusted and obtained through experimental data or long-term observation, represents the cumulative working duration of the flow battery, k represents the attenuation coefficient, which is related to the performance of the flow battery, indicating that as the cumulative working duration increases, the performance evaluation index of the flow battery decreases, and the amount of decrease depends on the specific performance of the flow battery, represents the rated working power of the flow battery, represents the influence coefficient of the rated working power of the flow battery on the performance of the flow battery. The value of it reflects the influence of the rated working efficiency on the overall performance of the flow battery, and can be adjusted and obtained through experimental data or long-term observation.

[0048] The weight factor of the performance evaluation index corresponding to the cumulative working hours is the influence factor corresponding to the cumulative working hours preset in the flow battery database, which represents the numerical value of the influence degree of the cumulative working hours on the performance evaluation index of the flow battery. When in use, the influence factor corresponding to the cumulative working hours can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the current cumulative working hours of the flow battery and the influence factor corresponding to the cumulative working hours preset in the flow battery database form a mapping set, and the real-time working hours of the flow battery are input into the mapping set to obtain its corresponding influence factor, where the mapping relationship can be one-to-one or many-to-one. In this example, its value range is [0,1]. The product of the influence coefficient of the cumulative working hours on the performance of the flow battery and the relevant formula of the cumulative working hours of the flow battery represents the non-linear influence of the cumulative working hours on the performance evaluation index, and at the same time takes into account the attenuation of the performance over time; the weight factor of the performance evaluation index corresponding to the rated working power is the influence factor corresponding to the rated working power preset in the flow battery database, which represents the numerical value of the influence degree of the rated working power on the performance evaluation index of the flow battery. When in use, the influence factor corresponding to the rated working power can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the rated working power of the flow battery and the influence factor corresponding to the rated working power preset in the flow battery database form a mapping set, and the real-time rated working power of the flow battery is input into the mapping set to obtain its corresponding influence factor, where the mapping relationship can be one-to-one or many-to-one. In this example, its value range is [0,1]. The product of the rated working power of the flow battery and the influence coefficient of the rated working power of the flow battery on the performance directly reflects the linear influence of the rated working power on the performance evaluation index. The greater the rated working power, the higher the performance evaluation index of the flow battery.

[0049] Further, the steps of adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery include: obtaining the constant current reference current value range of the constant current charging mode and the constant voltage reference voltage value range of the constant voltage charging mode according to the performance evaluation index of the flow battery; adjusting the charging current of the flow battery once according to the constant current reference current value range in the constant current charging mode, and adjusting the charging voltage of the flow battery once according to the constant voltage reference voltage value range in the constant voltage charging mode; after the first adjustment of the charging state, monitoring the temperature data of the flow battery and adjusting the charging current of the flow battery twice according to the temperature data of the flow battery.

[0050] In this embodiment, by detecting the charging state of the flow battery in real time, adjusting the charging mode of the flow battery according to the charging state, and continuously performing primary and secondary adjustments according to the charging mode of the flow battery, the real-time adjustment of the charging voltage and charging current of the flow battery is completed. Through real-time monitoring and intelligent adjustment, battery failures or system abnormalities caused by improper charging can be reduced, and the stability and reliability of the entire system can be improved. Based on the precise parameter setting and adjustment of the performance evaluation index, it can be ensured that the flow battery can be charged with the optimal current and voltage at different charging stages, thereby improving the charging efficiency.

[0051] Further, the steps of obtaining the constant current reference current value range of the constant current charging mode and the constant voltage reference voltage value range of the constant voltage charging mode according to the flow battery performance evaluation index include: matching the flow battery performance evaluation index with the constant current reference current value and the constant voltage reference voltage value corresponding to each flow battery performance evaluation index interval stored in the flow battery database to obtain the constant current reference current value and the constant voltage reference voltage value of the flow battery, constructing a mapping set of the flow battery performance evaluation index interval and the constant current reference current value and the constant voltage reference voltage value of the flow battery through historical data, determining the flow battery performance evaluation index interval according to the flow battery performance evaluation index, and obtaining the constant current reference current value and the constant voltage reference voltage value of the flow battery from the mapping set.

[0052] Obtain the preset allowable deviation charging current and allowable deviation charging voltage from the flow battery database; perform subtraction and summation operations on the constant current reference current value and the allowable deviation charging current respectively, and mark the difference result and the summation result as the reference current lower limit and the reference current upper limit respectively, and mark the range between the reference current lower limit and the reference current upper limit as the constant current reference current value range; perform subtraction and summation operations on the constant voltage reference voltage value and the allowable deviation charging voltage respectively, and mark the difference result and the summation result as the reference voltage lower limit and the reference voltage upper limit respectively, and mark the range between the reference voltage lower limit and the reference voltage upper limit as the constant voltage reference voltage value range.

[0053] In this embodiment, the allowable deviation is to ensure that in the actual charging process, even if there are small parameter fluctuations, the safety and charging efficiency of the battery can be guaranteed. By matching the flow battery performance evaluation index and calculating the allowable deviation, the charging current and charging voltage of the flow battery can be precisely controlled to ensure that it is charged under optimal conditions.

[0054] Further, the step of performing a primary adjustment on the charging current of the flow battery according to the constant-current reference current value range in the constant-current charging mode includes: when the charging mode of the flow battery is the constant-current charging mode, monitoring the charging current of the flow battery, and marking the absolute value of the difference between the charging current of the flow battery and the constant-current reference current value as the current parameter to be adjusted; if the charging current of the flow battery is greater than or equal to the lower limit of the reference current and less than or equal to the upper limit of the reference current, then maintaining the charging state of the flow battery; if the charging current of the flow battery is greater than the upper limit of the reference current, then reducing the charging current of the flow battery according to the current parameter to be adjusted; if the charging current of the flow battery is less than the lower limit of the reference current, then increasing the charging current of the flow battery according to the current parameter to be adjusted.

[0055] In this embodiment, the charging current of the flow battery can be adjusted by using a high-frequency isolation technology for the charging device of the flow battery. The high-frequency isolation technology is a method of achieving electrical isolation through a high-frequency transformer. It can indirectly control the charging current by adjusting the output voltage of the charging device without directly changing the circuit of the flow battery. When adjusting by using the high-frequency isolation technology, a high-frequency isolation converter with sufficient power capacity, voltage and current adjustment ranges, and good electrical isolation performance is selected. According to the target output voltage and the specific requirements of the charging device, parameters such as the input voltage, output voltage range, and switching frequency of the high-frequency isolation converter are set. By changing the ratio of the number of turns of the output winding to the number of turns of the input winding, the output voltage of the charging device is adjusted. When the charging current of the flow battery needs to be reduced, the number of turns of the output winding is increased relative to the number of turns of the input winding, resulting in a decrease in the output voltage of the charging device, thereby reducing the charging voltage of the flow battery and causing a decrease in the charging current of the flow battery; when the charging current of the flow battery needs to be increased, the number of turns of the output winding is decreased relative to the number of turns of the input winding, resulting in an increase in the output voltage of the charging device, thereby increasing the charging voltage of the flow battery and causing an increase in the charging current of the flow battery. At the same time, by combining the adjustment of the duty cycle of the Pulse Width Modulation (PWM) signal of the high-frequency isolation converter with the adjustment of the winding turn ratio, more detailed current control can be provided. The PWM signal is a technology for modulating an electrical signal, and the output power or the average value of the signal is controlled by changing the width of the pulse. The duty cycle is the ratio of the pulse width to the repetition time of the pulse and determines the average voltage of the PWM signal.

[0056] Further, the steps of secondarily adjusting the charging current of the flow battery according to the temperature data of the flow battery include: monitoring the temperature and the temperature change rate of the flow battery, which are recorded as the temperature data of the flow battery; processing the temperature data of the flow battery to obtain an abnormal temperature evaluation value of the flow battery; obtaining a preset abnormal temperature evaluation threshold from the flow battery database. When the abnormal temperature evaluation value of the flow battery is higher than the preset abnormal temperature evaluation threshold, a current correction value is obtained by matching the difference between the abnormal temperature evaluation value of the flow battery and the abnormal temperature evaluation threshold. According to the adjustment current value corresponding to the current correction value level, the output voltage of the flow battery charging device is controlled by using high-frequency isolation technology to adjust the charging current of the flow battery.

[0057] In this embodiment, the current correction value is divided into multiple levels according to the accuracy of the difference between the abnormal temperature evaluation value of the flow battery and the abnormal temperature evaluation threshold, and each level corresponds to an adjusted current value. For example, the current correction value can be divided into 10,000 levels. The first level is the level with the smallest difference, specifically, the difference is less than 0.001, the second level is 0.001 - 0.002, and so on. The larger the difference between the abnormal temperature evaluation value of the flow battery and the abnormal temperature evaluation threshold, the higher the level of the current correction value, and the larger the corresponding adjusted current value. Moreover, the more levels the current correction value has, the finer the adjusted current value is. This grading standard can accurately adjust the charging current of the flow battery, make a flexible response according to the actual situation, and avoid over-adjustment or unnecessary adjustment.

[0058] Further, the calculation formula for the abnormal temperature evaluation value of the flow battery is:

[0059] ;

[0060] In the formula, δ represents the abnormal temperature evaluation value of the flow battery, μ represents the weight factor of the abnormal temperature evaluation value of the flow battery corresponding to the temperature of the flow battery, λ represents the weight factor of the abnormal temperature evaluation value of the flow battery corresponding to the temperature change rate, represents the critical temperature of the flow battery, represents the current temperature of the flow battery, represents the critical temperature change rate of the flow battery, represents the current temperature change rate of the flow battery.

[0061] In this embodiment, the weight factor of the abnormal temperature evaluation value of the flow battery corresponding to the temperature is the influence factor preset in the flow battery database, which represents the numerical value of the influence degree of the flow battery temperature on the abnormal temperature evaluation value of the flow battery. When in use, the influence factor corresponding to the temperature can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the flow battery temperature under the charging state and the influence factor corresponding to the preset flow battery temperature in the flow battery database form a mapping set, and the real-time temperature is input into the mapping set to obtain the influence factor corresponding to the current temperature. The mapping relationship therein can be a one-to-one or many-to-one relationship. In this example, its value range is [0,1]. The current temperature of the flow battery can be directly measured by a temperature sensor. The ratio of the current temperature of the flow battery to the critical temperature of the flow battery is used to evaluate the abnormal temperature evaluation value of the flow battery from the perspective of temperature. The higher the temperature, the greater the abnormal temperature evaluation value of the flow battery. The weight factor of the abnormal temperature evaluation value of the flow battery corresponding to the temperature change rate is the influence factor corresponding to the preset flow battery temperature change rate in the flow battery database, which represents the numerical value of the influence degree of the flow battery temperature change rate on the abnormal temperature evaluation value of the flow battery. When in use, the influence factor corresponding to the temperature can be directly obtained from the flow battery database, and its corresponding relationship can be a pre-set mapping relationship. For example, the flow battery temperature change rate under the charging state and the influence factor corresponding to the preset flow battery temperature change rate in the flow battery database form a mapping set, and the real-time temperature change rate is input into the mapping set to obtain the influence factor corresponding to the current temperature change rate. The mapping relationship therein can be a one-to-one or many-to-one relationship. In this example, its value range is [0,1]. The temperature change rate of the flow battery can be obtained by calculating the temperature change rate between two time points using the temperature data of the temperature sensor at different time points. When the flow battery is charging, the same time interval is set within each time sampling point, and the temperature change rate within each time interval is calculated. The ratio of the current temperature change rate of the flow battery to the critical temperature change rate can be used to evaluate the abnormal temperature evaluation value of the flow battery from the perspective of the temperature change rate. The greater the current temperature change rate, the greater the abnormal temperature evaluation value of the flow battery.

[0062] Set the critical temperature of the flow battery to 25, the critical temperature change rate of the flow battery to 0.05, the weight factor of the abnormal temperature evaluation value of the flow battery corresponding to the temperature to 0.7, and the weight factor of the abnormal temperature evaluation value of the flow battery corresponding to the temperature change rate to 0.3. Calculate the abnormal temperature evaluation value of the flow battery under the condition that the current temperature change rate of the flow battery is the same and the temperature changes. As shown in Table 1, the data table of the abnormal temperature evaluation value of the flow battery based on the high-frequency isolation technology:

[0063] Table 1 Data Table of Abnormal Temperature Evaluation Values of Flow Batteries Based on High-Frequency Isolation Technology

[0064]

[0065] As Figure 2 shown, it is a graph of the change in the abnormal temperature evaluation value of the flow battery for the method of improving the energy storage efficiency of the flow battery based on high-frequency isolation technology provided by the embodiment of the present application. It can be seen from Figure 2 and Table 1 that when the weight factors of the abnormal temperature evaluation value of the flow battery corresponding to the temperature of the flow battery and the weight factors of the abnormal temperature evaluation value of the flow battery corresponding to the temperature change rate are the same, as the current temperature of the flow battery increases, the change situation of the abnormal temperature evaluation value of the flow battery. Among them, the temperature change rate of the current flow battery of the green curve is 0.3, the temperature change rate of the current flow battery of the orange curve is 0.2, and the temperature change rate of the current flow battery of the blue curve is 0.1. The larger the abnormal temperature evaluation value of the battery, the faster the change degree indicates that the abnormal situation of the current flow battery is more dangerous, and it is necessary to timely adjust the charging current and charging voltage of the flow battery by using high-frequency isolation technology to control the abnormal temperature situation of the flow battery.

[0066] In summary, the embodiment of the present application realizes precise control of the charging current and charging voltage of the flow battery by adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery, thereby improving the energy storage efficiency of the flow battery.

[0067] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can be implemented in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can be implemented in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0068] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable processing devices generate a device for realizing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0069] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable processing device to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more processes and / or blocks Figure 1 in one or more processes and / or blocks Figure 1 specified in the function.

[0070] These computer program instructions may also be loaded onto a computer or other programmable processing device, such that a series of operational steps are performed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes and / or blocks Figure 1 in one or more processes and / or blocks Figure 1 specified in the function.

[0071] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0072] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology, characterized in that, The steps include: Monitoring the charge state data of the flow battery and analyzing to obtain the flow battery charge state index; Adjusting the flow battery charging mode according to the flow battery charge state index, where the flow battery charging mode includes a constant current charging mode and a constant voltage charging mode; Collecting the flow battery performance data, processing to obtain the flow battery performance evaluation index, matching to obtain the constant current reference current value and the constant voltage reference voltage value according to the flow battery performance evaluation index, and adjusting the charging current and charging voltage of the flow battery in real time according to the flow battery charging mode; The step of monitoring the charge state data of the flow battery and analyzing to obtain the flow battery charge state index includes: The charge state data of the flow battery includes the electrolyte concentration, current efficiency, and charging time of the flow battery; Comprehensively analyzing according to the electrolyte concentration, current efficiency, and charging time of the flow battery to obtain the flow battery charge state index; The step of collecting the flow battery performance data and processing to obtain the flow battery performance evaluation index includes: obtaining the cumulative working duration and rated working power of the flow battery as the flow battery performance data; Comprehensively analyzing according to the flow battery performance data to obtain the flow battery performance evaluation index; The step of adjusting the charging current and charging voltage of the flow battery in real time according to the flow battery charging mode includes: obtaining the constant current reference current value range of the constant current charging mode and the constant voltage reference voltage value range of the constant voltage charging mode according to the flow battery performance evaluation index; Adjusting the charging current of the flow battery once according to the constant current reference current value range in the constant current charging mode, and adjusting the charging voltage of the flow battery once according to the constant voltage reference voltage value range in the constant voltage charging mode; After the first adjustment of the charge state, monitoring the temperature data of the flow battery and adjusting the charging current of the flow battery a second time according to the temperature data of the flow battery; The step of adjusting the charging current of the flow battery a second time according to the temperature data of the flow battery includes: monitoring the temperature and temperature change rate of the flow battery, recorded as the temperature data of the flow battery; Processing according to the temperature data of the flow battery to obtain the flow battery temperature anomaly evaluation value; Obtaining the preset temperature anomaly evaluation threshold from the flow battery database. When the flow battery temperature anomaly evaluation value is higher than the preset temperature anomaly evaluation threshold, matching to obtain the current correction value according to the flow battery temperature anomaly evaluation value and adjusting the charging current according to the current correction value.

2. The method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology according to claim 1, characterized in that: The specific calculation formula of the flow battery charge state index is: Where ξ represents the charge state index of the flow battery, α represents the weight factor of the charge state index of the flow battery corresponding to the electrolyte concentration, β represents the weight factor of the charge state index of the flow battery corresponding to the current efficiency, γ represents the weight factor of the charge state index of the flow battery corresponding to the charging time, and C now represents the electrolyte concentration of the current flow battery, and C max represents the threshold of the electrolyte concentration range when the flow battery is nearly fully charged, and E now represents the current efficiency of the current flow battery, and E rated represents the rated current efficiency of the flow battery, and t now represents the charging time of the current flow battery, and t max represents the maximum charging time of the flow battery.

3. The method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology according to claim 1, characterized in that: The specific process of adjusting the flow battery charging mode according to the flow battery charge state index includes: First, obtaining the preset flow battery charge state index threshold from the flow battery database; Comparing the flow battery charge state index with the flow battery charge state index threshold. If the flow battery charge state index is less than the flow battery charge state index threshold, adjusting the flow battery charging mode to the constant current charging mode. If the flow battery charge state index is greater than or equal to the flow battery charge state index threshold, switching the flow battery charging mode to the constant voltage charging mode.

4. The method for improving the energy storage efficiency of a liquid flow battery based on the high-frequency isolation technology according to claim 1, wherein: The steps of obtaining the constant-current reference current value range for the constant-current charging mode and the constant-voltage reference voltage value range for the constant-voltage charging mode according to the flow battery performance evaluation index include: Matching the flow battery performance evaluation index with the constant-current reference current value and the constant-voltage reference voltage value corresponding to each flow battery performance evaluation index interval stored in the flow battery database to obtain the constant-current reference current value and the constant-voltage reference voltage value of the flow battery; Obtaining the preset allowable deviation charging current and allowable deviation charging voltage from the flow battery database; Performing subtraction and summation operations on the constant-current reference current value and the allowable deviation charging current respectively, marking the difference result and the summation result as the reference current lower limit and the reference current upper limit respectively, and marking the range between the reference current lower limit and the reference current upper limit as the constant-current reference current value range; Performing subtraction and summation operations on the constant-voltage reference voltage value and the allowable deviation charging voltage respectively, marking the difference result and the summation result as the reference voltage lower limit and the reference voltage upper limit respectively, and marking the range between the reference voltage lower limit and the reference voltage upper limit as the constant-voltage reference voltage value range.

5. The method for improving the energy storage efficiency of a liquid flow battery based on high-frequency isolation technology according to claim 4, wherein: The steps of adjusting the charging current of the flow battery once according to the constant-current reference current value range in the constant-current charging mode include: When the charging mode of the flow battery is the constant-current charging mode, monitoring the charging current of the flow battery, and marking the absolute value of the difference between the charging current of the flow battery and the constant-current reference current value as the current parameter to be adjusted; If the charging current of the flow battery is greater than or equal to the reference current lower limit and less than or equal to the reference current upper limit, maintaining the charging state of the flow battery; If the charging current of the flow battery is greater than the reference current upper limit, reducing the charging current of the flow battery according to the current parameter to be adjusted; If the charging current of the flow battery is less than the reference current lower limit, increasing the charging current of the flow battery according to the current parameter to be adjusted.

6. The method for improving the energy storage efficiency of a liquid flow battery based on high-frequency isolation technology according to claim 1, wherein: The calculation formula for the abnormal evaluation value of the flow battery temperature is: Where, δ represents the evaluation value of the abnormal temperature of the flow battery, μ represents the weight factor of the evaluation value of the abnormal temperature of the flow battery corresponding to the temperature of the flow battery, λ represents the weight factor of the evaluation value of the abnormal temperature of the flow battery corresponding to the temperature change rate, and T rated represents the critical temperature of the flow battery, and T now represents the current temperature of the flow battery, and V rated represents the critical temperature change rate of the flow battery, and V now represents the temperature change rate of the current flow battery.

Images