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

Abstract

The invention discloses a method for improving the energy storage efficiency of a flow battery based on a high-frequency isolation technology, and belongs to the technical field of new-generation information. The method comprises the following steps: monitoring charging state data of the flow battery, and analyzing to obtain a charging state index of the flow battery; according to the charging state index of the flow battery, the charging mode of the flow battery is adjusted, and the charging mode of the flow battery comprises a constant-current charging mode and a constant-voltage charging mode; the method comprises the following steps: collecting performance data of the flow battery, processing to obtain a performance evaluation index of the flow battery, matching to obtain 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 the charging voltage of the flow battery in real time according to a charging mode of the flow battery. The charging current and the charging voltage of the flow battery are adjusted in real time according to the charging mode of the flow battery, so that the charging current and the charging voltage of the flow battery are accurately controlled.

Description

Technical Field

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

[0002] As the global energy transition progresses, energy storage technology becomes increasingly important and is considered one of the key technologies to achieve energy transition. In order to meet the intermittent output of renewable energy, flow batteries have become an ideal choice for long-term energy storage due to their long life, high safety and flexibility.

[0003] The existing liquid flow battery energy storage system stores and releases energy through the charge and discharge process of the liquid flow battery. The positive and negative electrolytes of the liquid flow battery are respectively stored in two tanks, and the electrolytes are circulated through the battery using a liquid pump. Inside the battery stack, the positive and negative electrolytes are separated by an ion exchange membrane, and the battery is connected to an external load and power supply.

[0004] For example, the liquid flow battery and liquid flow battery stack disclosed in the patent application with publication number CN103413960A include: a first bipolar plate, a second bipolar plate, two liquid flow frames, two electrodes and an ion exchange membrane, the ion exchange membrane is clamped between the two electrodes, the two electrodes are respectively embedded in the cavities of the two liquid flow frames, a reaction space is formed between the current collecting surfaces of the first bipolar plate and the second bipolar plate facing each other, the current collecting surface of the first bipolar plate includes a first concave portion, the current collecting surface of the second bipolar plate includes a first convex portion matching the first concave portion, and the two electrodes and the ion exchange membrane form a concave-convex structure adapted 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 concave-convex structure, the area of ​​the electrodes and the ion exchange membrane is increased, the internal resistance of the liquid flow battery is reduced, and the current density of the liquid flow battery is increased, so as to achieve the purpose of improving the efficiency and power of the liquid flow battery.

[0005] For example, the invention patent with announcement number: CN114665135B announces a high voltage and efficiency liquid flow battery system, specifically relates to a high voltage and efficiency liquid flow battery system, to help the design, evaluation and performance optimization of liquid flow batteries. On the one hand, this invention patent uses a method for detecting membrane contamination to test that the battery resistance change is less than 50% during the battery charging and discharging process, and judges that the battery does not have membrane contamination. If it exceeds this range, it is judged that membrane contamination occurs. To determine whether there is a need to replace the battery or membrane, to cope with long-life or other demanding battery application scenarios. On the other hand, a membrane-fouling resistant 4-hydroxy-2,2,6,6-tetramethylpiperidinoxide / zinc liquid flow battery system is also provided. The liquid flow battery uses a polyvinylidene fluoride porous membrane without membrane contamination, which has better battery cycle performance and reduces the cost of the liquid flow battery from both the positive electrode active material and the membrane, which will further promote the development of liquid flow batteries.

[0006] However, in the process of implementing the technical solution of the invention in the embodiments of the present application, the present application found that the above technology has at least the following technical problems:

[0007] In the prior art, when a flow battery is charged, the charging current and charging voltage of the flow battery are unstable, causing the internal potential difference of the flow battery to fluctuate, which affects the electrochemical reaction efficiency of the flow battery and results in 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, thereby solving the problem in the prior art that when the flow battery is charged, the charging current and charging voltage of the flow battery are unstable, resulting in fluctuations in the internal potential difference of the flow battery, affecting the electrochemical reaction efficiency of the flow battery and causing low energy storage efficiency of the flow battery. The method achieves real-time adjustment of the charging current and charging voltage of the flow battery according to the charging state of the flow battery, thereby improving the energy storage efficiency of the flow battery.

[0009] The embodiment of the present application provides a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology, comprising the following steps: monitoring the charging status data of the flow battery, and analyzing to obtain a charging status index of the flow battery; adjusting the charging mode of the flow battery according to the charging status index of the flow battery, wherein 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, and obtaining a performance evaluation index of the flow battery after processing; according to the performance evaluation index of the flow battery, matching to obtain a constant current reference current value and a constant voltage reference voltage value, 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] Furthermore, the steps of monitoring the charging status data of the flow battery and analyzing to obtain the charging status index of the flow battery include: the charging status data of the flow battery includes the electrolyte concentration, current efficiency and charging time of the flow battery; and obtaining the charging status index of the flow battery through comprehensive analysis based on the electrolyte concentration, current efficiency and charging time of the flow battery.

[0011] Furthermore, the specific calculation formula of the liquid flow battery charging state indicator is:

[0012]

[0013] In the formula, 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 nowrepresents the current electrolyte concentration of the flow battery, C max The threshold value of the electrolyte concentration range when the flow battery is close to being fully charged, E now Represents the current efficiency of the current flow battery, E rated represents the rated current efficiency of the flow battery, t now represents the current charging time of the flow battery, t max Indicates the maximum charging time of the flow battery.

[0014] Furthermore, according to the liquid flow battery charging state index, the specific process of adjusting the liquid flow battery charging mode includes: first, obtaining a preset liquid flow battery charging state index threshold from the liquid flow battery database; comparing the liquid flow battery charging state index with the liquid flow battery charging state index threshold; if the liquid flow battery charging state index is less than the liquid flow battery charging state index threshold, adjusting the liquid flow battery charging mode to a constant current charging mode; if the liquid flow battery charging state index is greater than or equal to the liquid flow battery charging state index threshold, switching the liquid flow battery charging mode to a constant voltage charging mode.

[0015] Furthermore, the steps of collecting liquid flow battery performance data and obtaining a liquid flow battery performance evaluation index after processing include: obtaining the cumulative working time and rated working power of the liquid flow battery as liquid flow battery performance data; and obtaining a liquid flow battery performance evaluation index through comprehensive analysis based on the liquid flow battery performance data.

[0016] Furthermore, the step of adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery includes: obtaining a constant current reference current value range of the constant current charging mode and a 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 charging state is adjusted once, the temperature data of the flow battery is monitored, and the charging current of the flow battery is adjusted for a second time according to the temperature data of the flow battery.

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

[0018] Furthermore, the step of adjusting 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 reference current lower limit, and the charging current is 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] Furthermore, the step of performing secondary adjustment on the charging current of the flow battery according to the temperature data of the flow battery includes: 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 flow battery temperature anomaly assessment value according to the temperature data of the flow battery; obtaining a preset temperature anomaly assessment threshold from a flow battery database, and when the temperature anomaly assessment value of the flow battery is higher than the preset temperature anomaly assessment threshold, obtaining a current correction value according to the matching of the temperature anomaly assessment value of the flow battery, and adjusting the charging current according to the current correction value.

[0020] Furthermore, the calculation formula for the abnormal temperature assessment value of the flow battery is:

[0021]

[0022] 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, T rated represents the critical temperature of the flow battery, T now Indicates the current temperature of the flow battery, V rated represents the critical temperature change rate of the flow battery, V now Indicates the current rate of change of flow battery temperature.

[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. The present invention adjusts the charging current and charging voltage of the liquid flow battery in real time according to the charging state of the liquid flow battery, thereby reducing the loss of active materials inside the liquid flow battery and reducing energy loss, thereby improving the energy storage efficiency of the liquid flow battery.

[0025] 2. The present invention adjusts the liquid flow battery once according to the optimal constant current reference current value range and the optimal constant voltage reference voltage value range, thereby avoiding battery overcharging and improving the safety of the liquid flow battery charging process.

[0026] 3. The present invention adjusts the charging mode of the flow battery by analyzing the charging state index of the flow battery, thereby improving the charging efficiency and shortening the charging time of the flow battery. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 2 A graph showing changes in abnormal flow battery temperature assessment values ​​for a method for improving flow battery energy storage efficiency based on high-frequency isolation technology provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The embodiment of the present application provides a method for improving the energy storage efficiency of a flow battery based on a high-frequency isolation technology, thereby solving the problem in the prior art that when the flow battery is charged, the internal potential difference of the flow battery fluctuates due to the instability of the charging current and charging voltage of the flow battery, which affects the electrochemical reaction efficiency of the flow battery and causes low energy storage efficiency of the flow battery. The charging state data of the flow battery is monitored and analyzed to obtain a charging state index of the flow battery, and then the charging mode of the flow battery is adjusted according to the charging state index of the flow battery, wherein 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 processed to obtain a performance evaluation index of the flow battery. 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 embodiment of the present application is to solve the problem in the above-mentioned prior art that when the flow battery is charged, the charging current and charging voltage of the flow battery are unstable, resulting in fluctuations in the internal potential difference of the flow battery, which affects the electrochemical reaction efficiency of the flow battery and causes low energy storage efficiency of the flow battery. The overall idea is as follows:

[0031] The charging status data of the flow battery is monitored and analyzed to obtain the charging status index of the flow battery, and then the charging mode of the flow battery is adjusted according to the charging status index of the flow battery, and the flow battery charging mode includes a constant current charging mode and a constant voltage charging mode. The flow battery performance data is then collected and processed to obtain a flow battery performance evaluation index. According to the flow battery performance evaluation index, 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 flow battery charging mode, thereby achieving real-time adjustment of the charging current and charging voltage of the flow battery according to the charging status of the flow battery, thereby improving the charging efficiency and service life of the flow battery.

[0032] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] like Figure 1As shown, it is a flow chart of a method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology provided in an embodiment of the present application, the method comprising the following steps: first, monitoring the charging status data of the flow battery, analyzing to obtain a charging status index of the flow battery, which is an important basis for evaluating the current power state of the battery, and then adjusting the charging mode of the flow battery according to the charging status index of the flow battery, wherein the charging mode of the flow battery includes a constant current charging mode and a constant voltage charging mode, and then collecting the performance data of the flow battery, and obtaining a flow battery performance evaluation index after processing, which is used to evaluate the health state and performance of the battery, and according to the performance evaluation index of the flow battery, matching to obtain a constant current reference current value and a constant voltage reference voltage value, and adjusting 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 maintain a constant value 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 battery performance. The constant current charging mode is generally used in the initial charging stage of the battery and in scenarios where power needs to be quickly replenished; 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 battery voltage is stable during the charging process, thereby protecting the battery from damage such as overcharging. The constant voltage charging mode is usually used in the later stages 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 maintenance charging of batteries to maintain battery performance and life. In addition, the method for improving the energy storage efficiency of liquid flow batteries in this embodiment can not only ensure that the battery is charged in the best state, thereby improving charging efficiency and reducing charging time, but also reduce 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] Furthermore, the steps of monitoring the charging status data of the flow battery and analyzing to obtain the charging status index of the flow battery include: the charging status data of the flow battery includes the electrolyte concentration, current efficiency and charging time of the flow battery; and obtaining the charging status index of the flow battery through comprehensive analysis based on the electrolyte concentration, current efficiency and charging time of the flow battery.

[0036] In this embodiment, the electrolyte is a key substance for storing and transferring energy in the flow battery, and 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 amount of electricity increases, the electrolyte concentration also increases continuously. When the charging is nearly completed, the electrolyte concentration can reach a relatively stable state. The electrolyte concentration can be directly obtained by measuring the electrolyte analyzer or by using the characteristics that ions will move to the electrode 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 amount of charge transferred to the theoretical amount of charge transferred during the battery charging or discharging process. It is one of the important indicators for evaluating battery performance and can reflect the energy conversion efficiency inside the battery. During the charging process, the internal chemical reaction and electrolyte state of the flow battery are gradually optimized, and the current efficiency is continuously improved. However, at the end of charging, the internal resistance of the flow battery increases and the limitation of the chemical reaction leads to increased energy loss and reduced 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, and calculating the charging power and discharging power, which can be obtained based on the ratio of charging power to 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 full charge), which can be directly obtained by stopwatch timing. By monitoring the charging time, the charging speed and charging efficiency of the battery can be evaluated. The electrolyte concentration, current efficiency and charging time of the flow battery can be used to comprehensively evaluate the charging state indicators of the flow battery, and by analyzing the abnormal changes in the charging state data, battery problems can be discovered and handled in a timely manner to avoid the expansion of faults or affecting the normal operation of the system.

[0037] Furthermore, the specific calculation formula of the liquid flow battery charging state indicator is:

[0038]

[0039] In the formula, 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 current electrolyte concentration of the flow battery, C max The threshold value of the electrolyte concentration range when the flow battery is close to being fully charged, E now Represents the current efficiency of the current flow battery, E rated represents the rated current efficiency of the flow battery, t now represents the current charging time of the flow battery, t max Indicates the maximum charging time of the flow battery.

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

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

[0042] In this embodiment, by dynamically switching the charging mode according to the actual charging status of the battery, it can be ensured that the battery can be charged in the optimal manner at different power stages, thereby improving the charging efficiency. The constant voltage charging mode can reduce the risk of overcharging when the battery is close to full charge, while the constant current charging mode can quickly replenish the battery when the battery power is low. The combination of these two modes helps to extend the service life of the battery. By realizing intelligent management of the liquid flow battery charging process, battery failure or system abnormality caused by improper charging can be reduced, thereby improving the stability and reliability of the entire system.

[0043] The liquid flow battery database is used to store data related to liquid flow battery charging regulation, including: liquid flow battery charging status indicators, liquid flow battery performance evaluation index, liquid flow battery temperature anomaly evaluation value, etc. The liquid flow battery database can be obtained by utilizing existing public databases or platforms, such as the National Energy Administration's energy storage database, the International Energy Agency's energy storage technology database, etc., or by conducting a large amount of liquid flow battery related data experimental entry.

[0044] Furthermore, the steps of collecting liquid flow battery performance data and obtaining a liquid flow battery performance evaluation index after processing include: obtaining the cumulative working time and rated working power of the liquid flow battery as liquid flow battery performance data; and obtaining a liquid flow battery performance evaluation index through comprehensive analysis based on the liquid flow battery performance data.

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

[0046]

[0047] In the formula, ε represents the performance evaluation index of the liquid flow battery, ρ represents the weight factor of the liquid flow battery performance evaluation index corresponding to the cumulative working time of the liquid flow battery, σ represents the weight factor of the liquid flow battery performance evaluation index corresponding to the rated working power, and ρ+σ=1, which can be extracted from the liquid flow battery database, C T It represents the influence coefficient of the cumulative working time on the performance of the flow battery. Its value reflects the influence of the cumulative working time on the battery performance. At the same time, its change can reflect the change of the performance of the flow battery as the use time of the flow battery increases. T It can be adjusted and obtained through experimental data or long-term observation. T represents the cumulative working time of the liquid flow battery. K represents the attenuation coefficient, which is related to the performance of the liquid flow battery. It means that as the cumulative working time increases, the liquid flow battery performance evaluation index decreases, and the amount of decrease depends on the specific performance of the liquid flow battery. P represents the rated working power of the liquid flow battery, and C P It represents the influence coefficient of the rated working power of the flow battery on the performance of the flow battery. Its value reflects the influence of the rated working efficiency on the overall performance of the flow battery, which can be adjusted and obtained through experimental data or long-term observation.

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

[0049] Furthermore, the step of adjusting the charging current and charging voltage of the flow battery in real time according to the charging mode of the flow battery includes: obtaining a constant current reference current value range of the constant current charging mode and a 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 charging state is adjusted once, the temperature data of the flow battery is monitored, and the charging current of the flow battery is adjusted for a second time according to the temperature data of the flow battery.

[0050] In this embodiment, the charging state of the flow battery is detected in real time, the charging mode of the flow battery is adjusted according to the charging state, and the primary and secondary adjustments are continuously performed according to the charging mode of the flow battery, thereby completing the real-time adjustment of the charging voltage and charging current of the flow battery. 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] Furthermore, the step of obtaining a constant current reference current value range for a constant current charging mode and a constant voltage reference voltage value range for a constant voltage charging mode according to a liquid flow battery performance evaluation index includes: matching the liquid flow battery performance evaluation index with the constant current reference current value and the constant voltage reference voltage value corresponding to each liquid flow battery performance evaluation index interval stored in a liquid flow battery database to obtain the constant current reference current value and the constant voltage reference voltage value of the liquid flow battery, constructing a mapping set of the liquid flow battery performance evaluation index interval and the constant current reference current value and the constant voltage reference voltage value of the liquid flow battery through historical data, determining the liquid flow battery performance evaluation index interval according to the liquid flow battery performance evaluation index, and obtaining the constant current reference current value and the constant voltage reference voltage value of the liquid flow battery from the mapping set.

[0052] The preset allowable deviation charging current and allowable deviation charging voltage are obtained from the liquid flow battery database; the constant current reference current value and the allowable deviation charging current are respectively subjected to difference and summation operations, and the difference result and the summation result are respectively marked as the reference current lower limit and the reference current upper limit, and the range between the reference current lower limit and the reference current upper limit is marked as the constant current reference current value range; the constant voltage reference voltage value and the allowable deviation charging voltage are respectively subjected to difference and summation operations, and the difference result and the summation result are respectively marked as the reference voltage lower limit and the reference voltage upper limit, and the range between the reference voltage lower limit and the reference voltage upper limit is marked as the constant voltage reference voltage value range.

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

[0054] Furthermore, the step of adjusting 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 reference current lower limit, and the charging current is 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.

[0055] In this embodiment, the charging current of the flow battery can be adjusted by using high-frequency isolation technology to adjust the charging device of the flow battery. 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 flow battery circuit. When adjusting by high-frequency isolation technology, a high-frequency isolation converter with sufficient power capacity, voltage and current adjustment range, and good electrical isolation performance is selected. According to the target output voltage and the specific requirements of the charging device, the input voltage, output voltage range, switching frequency and other parameters 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 end, 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, resulting in 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 reduced 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, resulting in an increase in the charging current of the flow battery. At the same time, the adjustment of the duty cycle of the pulse width modulation (PWM) signal of the high-frequency isolation converter, combined with the adjustment of the winding turn ratio, can provide more detailed current control. The PWM signal is a technology used to modulate electrical signals. It controls the output power or the average value of the signal by changing the width of the pulse. The duty cycle refers to the ratio of the pulse width to the pulse repetition time, which determines the average voltage of the PWM signal.

[0056] Furthermore, the step of performing secondary regulation on the charging current of the flow battery according to the temperature data of the flow battery includes: 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 flow battery temperature anomaly assessment value according to the temperature data of the flow battery; obtaining a preset temperature anomaly assessment threshold from a flow battery database, and when the temperature anomaly assessment value of the flow battery is higher than the preset temperature anomaly assessment threshold, matching the current correction value obtained by the difference between the temperature anomaly assessment value of the flow battery and the temperature anomaly assessment threshold, and regulating the charging current of the flow battery according to the regulated current value corresponding to the current correction value level, using high-frequency isolation technology to control the output voltage of the flow battery charging equipment.

[0057] In this embodiment, the current correction value is divided into multiple levels according to the accuracy of the difference between the temperature anomaly assessment value of the liquid flow battery and the temperature anomaly assessment 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 minimum difference level, specifically the difference is less than 0.001, the second level is 0.001-0.002, and so on. The greater the difference between the temperature anomaly assessment value of the liquid flow battery and the temperature anomaly assessment threshold, the higher the current correction value level, the larger the corresponding adjusted current value, and the more levels of current correction values, the finer the adjusted current value. This grading standard can accurately adjust the charging current of the liquid flow battery, make flexible responses according to actual conditions, and avoid excessive or unnecessary adjustments.

[0058] Furthermore, the calculation formula for the abnormal temperature assessment 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, T rated represents the critical temperature of the flow battery, T now Indicates the current temperature of the flow battery, V rated represents the critical temperature change rate of the flow battery, V now Indicates the current rate of change of flow battery temperature.

[0061] In this embodiment, the weight factor of the flow battery temperature anomaly assessment value corresponding to the temperature is the influence factor corresponding to the flow battery temperature preset in the flow battery database, which represents the numerical value of the influence degree of the flow battery temperature on the flow battery temperature anomaly assessment value. When used, the influence factor corresponding to the temperature can be directly obtained from the flow battery database, and the corresponding relationship can be a preset mapping relationship. For example, the flow battery temperature in the charging state and the influence factor corresponding to the flow battery temperature preset 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, and the mapping relationship can be a one-to-one correspondence or a 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 the 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 temperature change rate of the flow battery preset in the flow battery database, which represents the numerical value of the influence of the temperature change rate of the flow battery on the abnormal temperature evaluation value of the flow battery. When used, the influence factor corresponding to the temperature can be directly obtained from the flow battery database, and the corresponding relationship can be a preset mapping relationship. For example, the temperature change rate of the flow battery in the charging state and the influence factor corresponding to the temperature change rate of the flow battery preset 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 can be one-to-one or many-to-one. In this example, its value range is [0,1]. The temperature change rate of the flow battery can be obtained by using the temperature data of the temperature sensor at different time points to calculate the temperature change rate between two time points. When the flow battery is charging, the same time interval is set at 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 temperature anomaly assessment value of the flow battery from the perspective of the temperature change rate. The greater the current temperature change rate, the greater the temperature anomaly assessment value of the flow battery.

[0062] The critical temperature of the flow battery is set to 25, the critical temperature change rate of the flow battery is set to 0.05, the weight factor of the flow battery temperature anomaly assessment value corresponding to the flow battery temperature is set to 0.7, and the weight factor of the flow battery temperature anomaly assessment value corresponding to the temperature change rate is set to 0.3. According to the current flow battery temperature change rate, the flow battery temperature anomaly assessment value is calculated under the condition of temperature change. As shown in Table 1, the flow battery temperature anomaly assessment value data table based on high-frequency isolation technology:

[0063] Table 1 Data table of abnormal temperature assessment value of flow battery based on high frequency isolation technology

[0064] Serial number Tnow Vaow δ 1 35 0.1 2,647 2 36 0.1 2,662 3 37 0.1 2.677 4 38 0.1 2,691 5 39 0.1 2.705

[0065] like Figure 2 As shown, it is a flow battery temperature anomaly evaluation value change diagram of the flow battery energy storage efficiency improvement method based on high-frequency isolation technology provided in the embodiment of the present application, which is composed of Figure 2 It can be seen from Table 1 that, when the weight factor of the flow battery temperature anomaly assessment value corresponding to the temperature of the flow battery and the weight factor of the flow battery temperature anomaly assessment value corresponding to the temperature change rate are the same, as the current temperature of the flow battery increases, the flow battery temperature anomaly assessment value changes. Among them, the current temperature change rate of the green curve is 0.3, the current temperature change rate of the orange curve is 0.2, and the current temperature change rate of the blue curve is 0.1. The larger the battery temperature anomaly assessment value and the faster the change, the more dangerous the current abnormal condition of the flow battery is. It is necessary to use high-frequency isolation technology in time to adjust the charging current and charging voltage of the flow battery to control the abnormal temperature of the flow battery.

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

[0067] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take 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 flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a 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 specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0070] These computer program instructions may also be loaded onto a computer or other programmable processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0071] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and 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 equivalents, 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 following steps are involved: Monitor the charging status data of the flow battery and analyze the charging status indicators of the flow battery; According to the charge state indicator of the flow battery, adjusting the charge mode of the flow battery, the charge mode of the flow battery including a constant current charge mode and a constant voltage charge mode; The performance data of the liquid flow battery is collected and processed to obtain a liquid flow battery performance evaluation index. According to the liquid flow battery performance evaluation index, a constant current reference current value and a constant voltage reference voltage value are matched, and the liquid flow battery charging current and charging voltage are adjusted in real time according to the liquid flow battery charging mode.

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 step of monitoring the charging state data of the flow battery and analyzing to obtain the charging state index of the flow battery comprises: The charging state data of the flow battery includes electrolyte concentration, current efficiency and charging time of the flow battery; Based on the electrolyte concentration, current efficiency and charging time of the flow battery, a comprehensive analysis is performed to obtain the charge status index of the flow battery.

3. The method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology as claimed in claim 2, characterized in that: The specific calculation formula of the liquid flow battery charging state indicator is: In the formula, 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 current electrolyte concentration of the flow battery, C max The threshold value of the electrolyte concentration range when the flow battery is close to being fully charged, E now Represents the current efficiency of the current flow battery, E rated represents the rated current efficiency of the flow battery, t now represents the current charging time of the flow battery, t max Indicates the maximum charging time of the flow battery.

4. The method for improving the energy storage efficiency of a flow battery based on high frequency isolation technology as claimed in claim 2, characterized in that: The specific process of adjusting the charging mode of the flow battery according to the charge state indicator of the flow battery includes: First, a preset flow battery charging state indicator threshold is obtained from a flow battery database; The flow battery charging state index is compared 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 switched to the constant voltage charging mode.

5. 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 step of collecting flow battery performance data and obtaining a flow battery performance evaluation index through processing comprises: The accumulated working time and rated working power of the flow battery are obtained and recorded as performance data of the flow battery; Based on the performance data of the flow battery, a comprehensive analysis is conducted to obtain the flow battery performance evaluation index.

6. The method for improving the energy storage efficiency of a flow battery based on high-frequency isolation technology according to claim 5, characterized in that: The step of adjusting the charging current and charging voltage of the flow battery in real time according to the flow battery charging mode comprises: Obtaining a constant current reference current value range of a constant current charging mode and a constant voltage reference voltage value range of a constant voltage charging mode according to a flow battery performance evaluation index; In the constant current charging mode, the charging current of the flow battery is adjusted once according to the constant current reference current value range, and in the constant voltage charging mode, the charging voltage of the flow battery is adjusted once according to the constant voltage reference voltage value range; After the charging state is adjusted once, the temperature data of the flow battery is monitored, and the charging current of the flow battery is adjusted for a second time according to the temperature data of the flow battery.

7. The method for improving the energy storage efficiency of a flow battery based on high frequency isolation technology as claimed in claim 6, characterized in that: The step of obtaining a constant current reference current value range of a constant current charging mode and a constant voltage reference voltage value range of a constant voltage charging mode according to the liquid flow battery performance evaluation index comprises: Matching the liquid flow battery performance evaluation index with the constant current reference current value and constant voltage reference voltage value corresponding to each liquid flow battery performance evaluation index interval stored in the liquid flow battery database to obtain the constant current reference current value and constant voltage reference voltage value of the liquid flow battery; Obtaining a preset allowable deviation charging current and allowable deviation charging voltage from a flow battery database; Perform difference and sum operations on the constant current reference current value and the allowable deviation charging current, respectively, and mark the difference result and the sum 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; The constant voltage reference voltage value and the allowable deviation charging voltage are respectively subjected to difference and sum operations, and the difference result and the sum result are respectively marked as the reference voltage lower limit and the reference voltage upper limit, and the range between the reference voltage lower limit and the reference voltage upper limit is marked as the constant voltage reference voltage value range.

8. The method for improving the energy storage efficiency of a flow battery based on high frequency isolation technology as claimed in claim 7, characterized in that: The step of adjusting the charging current of the flow battery according to the constant current reference current value range in the constant current charging mode comprises: When the charging mode of the flow battery is the constant current charging mode, the charging current of the flow battery is monitored, and the absolute value of the difference between the charging current of the flow battery and the constant current reference current value is marked 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 the charging current is less than or equal to the reference current upper limit, the charging state of the flow battery is maintained; If the charging current of the flow battery is greater than the reference current upper limit, the charging current of the flow battery is reduced according to the current parameter to be adjusted; If the charging current of the flow battery is less than the reference current lower limit, the charging current of the flow battery is increased according to the current parameter to be adjusted.

9. The method for improving the energy storage efficiency of a flow battery based on high frequency isolation technology as claimed in claim 6, characterized in that: The step of performing secondary adjustment on the charging current of the flow battery according to the temperature data of the flow battery comprises: The temperature and temperature change rate of the flow battery are monitored and recorded as the temperature data of the flow battery; According to the temperature data of the flow battery, an abnormal temperature evaluation value of the flow battery is obtained by processing; A preset temperature anomaly assessment threshold is obtained from the liquid flow battery database. When the temperature anomaly assessment value of the liquid flow battery is higher than the preset temperature anomaly assessment threshold, a current correction value is obtained according to the temperature anomaly assessment value of the liquid flow battery, and the charging current is adjusted according to the current correction value.

10. The method for improving the energy storage efficiency of a flow battery based on high frequency isolation technology according to claim 9, characterized in that: The calculation formula of the abnormal temperature evaluation value of the flow battery is: 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, T rated represents the critical temperature of the flow battery, T now Indicates the current temperature of the flow battery, V rated represents the critical temperature change rate of the flow battery, V now Indicates the current rate of change of flow battery temperature.

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