A flow battery testing system

Abstract

The present invention discloses a liquid flow battery testing system, which relates to the field of battery testing technology and solves the problem of not specifically analyzing the influence of the vanadium ion concentration inside the liquid flow battery. The present invention executes different subsequent processing ends according to different comparison results, and the different processing ends use different battery inspection methods to identify the concentration of corresponding vanadium ions in the liquid flow battery. Based on the specific data analysis results, the specific vanadium ion concentration of the liquid flow battery is confirmed and displayed, so as to evaluate the abnormal situation of the liquid flow battery failing to meet the inspection standards, and generate corresponding abnormal signals for display, so as to facilitate external relevant personnel to view and take countermeasures in time, so as to achieve better liquid flow battery testing effect.

Description

Technical Field

[0001] The present invention relates to the technical field of battery testing, and in particular to a liquid flow battery testing system. Background Art

[0002] Liquid flow battery is an electrochemical energy storage technology proposed in 1974. It is a new type of battery. Liquid flow battery consists of a stack unit, an electrolyte, an electrolyte storage and supply unit, and a management and control unit. It is a high-performance battery that separates the positive and negative electrolytes and circulates them separately. It has the characteristics of high capacity, wide application range (environment), and long cycle life. It is a new energy product.

[0003] The application with publication number CN105158703A discloses a liquid flow battery testing system based on an energy storage unit, including: a plurality of test devices respectively connected to each liquid flow battery for performing charging test and discharging test on each liquid flow battery; each test device is connected to the power grid; an energy storage unit connected to the power grid and the liquid flow battery via the test device; a test management system connecting the liquid flow battery, the test device and the energy storage unit; the present invention optimizes the distribution of electric energy in the entire test system by scheduling liquid flow batteries and energy storage units with different test requirements through the test management system, effectively reduces the electric energy taken from the power grid and output to the power grid, and greatly reduces the consumption and cost of electric energy during the test.

[0004] During the testing process of its flow battery, the specific numerical performance of the corresponding flow battery during the charging and discharging process is generally used to evaluate whether the charge and discharge of the flow battery meets the standards. However, the original testing method can only generate charge and discharge fluctuations or normal charge and discharge signals for display. However, this testing method is not comprehensive enough and has not found the cause of the abnormality. It has not specifically analyzed the impact of the vanadium ion concentration inside the flow battery to ensure the comprehensiveness of the flow battery testing. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a liquid flow battery testing system, which solves the problem of not specifically analyzing the influence of the vanadium ion concentration inside the liquid flow battery.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A flow battery testing system, comprising:

[0007] The constant current test end uses a standard constant current to charge the flow battery, and generates a voltage change curve in real time based on the voltage change of the flow battery. When the voltage rise value per unit time is lower than the preset value X1, the charging is stopped, and the generated voltage change curve is transmitted to the constant current data verification end;

[0008] The constant current data verification end compares the generated voltage change curve with the standard curve preset in the standard database, identifies the specific proportion parameters of the corresponding standard line segment in the voltage change curve, and determines whether the liquid flow battery meets the initial test standards based on the specific proportion analysis results. The specific method is as follows:

[0009] Based on the determined standard curve, the initial point and the end point of the standard curve remain unchanged, and other points inside the standard curve are translated up and down, and the translation distance is Y1, where Y1 is a preset value. Based on the specific translation process of several points inside the standard curve, the floating area of ​​the upper and lower standards is locked;

[0010] Based on the determined floating area, the line segment in the voltage change curve belonging to the floating area is marked as the standard segment, and then the overall proportion Zb of the standard segment in the entire voltage change curve is determined, where Zb = standard segment line length ÷ total line length of the voltage change curve, and whether Zb satisfies: Zb>90%:

[0011] If so, a constant current test pass signal is generated;

[0012] If not, it means that the initial test of this flow battery fails, and the subsequent voltage evaluation terminal is executed to perform subsequent voltage numerical analysis;

[0013] The voltage assessment end, in case the liquid flow battery fails the initial test, first determines the voltage parameter corresponding to the liquid flow battery at the time of charging completion, checks the voltage parameter with the preset standard range, and determines the subsequent execution end based on the specific check result. The specific method is as follows:

[0014] The voltage parameter of the flow battery at the time of charging completion is calibrated as DY, and the voltage parameter DY is checked with a preset standard interval, wherein the endpoint values ​​of the standard interval are all preset values;

[0015] If DY∈standard interval, execute concentration difference assessment end;

[0016] If DY>standard range, execute charging rate analysis terminal;

[0017] If DY < standard range, execute the discharge test end;

[0018] The concentration difference assessment end uses rays of a specified wavelength to perform refraction analysis on the electrolyte in two different areas of the flow battery, identifies the refraction angles of the two different areas, and then assesses whether the electrolyte concentration in the positive and negative areas of the flow battery is abnormal based on the specific difference in the refraction angle values. The specific method is as follows:

[0019] Use designated equipment to generate rays of designated wavelengths to perform refraction analysis on the positive and negative electrode areas of the flow battery, and the irradiation angles of the rays and the electrolyte on the surfaces of the corresponding positive and negative electrode areas are consistent, identify the refraction angles of the rays, calibrate the refraction angles generated in the positive electrode area as Z1, and calibrate the refraction angles generated in the negative electrode area as Z2, where the selection methods of the refraction angles in the two positive and negative electrode areas are consistent;

[0020] Identify whether Z1 and Z2 satisfy: |Z1-Z2|>Y1. If so, generate abnormal concentration signals in the positive and negative regions. If not, generate a test error signal for display.

[0021] The charging rate analysis end generates a charging rate change curve for different charging rates corresponding to different times in this charging stage, and then identifies whether the electrolyte concentration in the flow battery exceeds the standard based on the value change of this charging rate change curve. The specific method is as follows:

[0022] Based on the different charging rates generated at different times, a charging rate variation curve is generated, where the charging rate is the amount of charge generated per unit time;

[0023] Confirm the location of the constant current in the coordinate system where the charging rate change curve is located, and construct a set of vertical lines perpendicular to this position, mark the vertical lines as standard lines, and based on the confirmed charging rate change curve, mark the part of the line segments below the standard line as lower segments, and mark the part of the line segments above the standard line as upper segments, whose constant current is the standard charging value per unit time and is a preset value, then determine the initial endpoint and the terminal endpoint of the charging rate change curve, construct a set of range lines passing through the initial endpoint and perpendicular to the standard line, and then construct a set of range lines passing through the terminal endpoint and perpendicular to the standard line;

[0024] Based on the determined range line and the charging rate change curve, the range area generated between the lower segment and the charging rate change curve is confirmed and the area parameter of the range area is calibrated as M1. Similarly, the area parameter M2 of the range area between the upper segment and the charging rate change curve is confirmed;

[0025] If M2>M1, a flow battery concentration exceeding standard signal is generated;

[0026] If M2≤M1, a check error signal is generated for display;

[0027] At the discharge test end, the flow battery is subjected to constant current discharge and its discharge duration is recorded to assess whether the electrolyte concentration of the flow battery is too low. The specific method is as follows:

[0028] Based on the constant current discharge process of this flow battery, its specific discharge duration is locked and calibrated as T1;

[0029] The discharge time T1 is compared with the preset minimum standard time Ts: if T1 < Ts, a low flow battery concentration signal is generated; if T1 ≥ Ts, a test error signal is generated for display, where Ts is a preset value.

[0030] The present invention provides a flow battery testing system. Compared with the prior art, it has the following beneficial effects:

[0031] The present invention analyzes the current data of the flow battery during the initial inspection process to identify whether the generation process of the current data meets the standard. Based on the specific inspection results, it is identified whether the flow battery is qualified during the initial inspection process. For the case of unqualified test, the voltage floating situation is identified, and the voltage floating is compared with the standard voltage to determine different comparison results.

[0032] According to the different comparison results generated, different subsequent processing ends are executed, and different processing ends use different battery inspection methods to identify the corresponding vanadium ion concentration in the liquid flow battery. Based on the specific data analysis results, the specific vanadium ion concentration of the liquid flow battery is confirmed and displayed, so as to assess the abnormal situation of the liquid flow battery that fails to meet the inspection standards, and generate corresponding abnormal signals for display, so as to facilitate external relevant personnel to view and take timely response measures to achieve better liquid flow battery testing results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the principle framework of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figure 1 , the present application provides a flow battery testing system, including a constant current testing terminal, a standard database, a constant current data checking terminal, a voltage evaluation terminal, a concentration difference evaluation terminal, a charging rate analysis terminal and a discharge testing terminal;

[0036] The constant current test terminal and the standard database are both electrically connected to the constant current data verification terminal input node, and the constant current data verification terminal is electrically connected to the voltage evaluation terminal input node, and the voltage evaluation terminal is electrically connected to the concentration difference evaluation terminal, the charging rate analysis terminal or the discharge test terminal input node respectively;

[0037] The constant current test end uses a standard constant current to charge the flow battery, and based on the voltage change of the flow battery, generates its voltage change curve in real time. When the voltage rise value per unit time is lower than the preset value X1, charging is stopped, and the generated voltage change curve is transmitted to the constant current data verification end. Specifically, X1 is a preset standard change voltage value, and its specific value is determined by the operator based on experience. Generally, when charging with a constant current, the voltage change of the corresponding flow battery is generally very small after the flow battery is fully charged. This situation represents that the flow battery has completed the overall charging process;

[0038] The constant current data checking end compares the generated voltage change curve with the standard curve preset in the standard database, identifies the specific proportion parameters of the corresponding standard line segment in the voltage change curve, and determines whether the liquid flow battery meets the initial test standard based on the specific proportion analysis results. Specifically, during the constant charging process of the liquid flow battery, due to the increase or corresponding decrease of the valence state between the internal electrolytes, the corresponding liquid flow battery stores electricity, and the internal voltage gradually increases. The corresponding voltage parameters are gradually added, and there will not be excessive fluctuations. Therefore, the corresponding voltage standard curve can be determined based on this type of liquid flow battery, and the inspection and judgment are performed based on the comparison results between the curves, wherein the specific method of making the judgment is:

[0039] Based on the determined standard curve, the initial point and the end point of the standard curve remain unchanged, and other points inside the standard curve are translated up and down, and the translation distance is Y1, where Y1 is a preset value, and the specific value of Y1 is determined by the operator based on experience, that is, the same point is not only translated upward by a group of distances Y1, but also translated downward by a distance Y1, then a straight line area is locked between the two points, and based on the specific translation process of several points inside the standard curve, the floating area of ​​the upper and lower standards is locked;

[0040] Based on the determined floating area, the line segment in the voltage change curve belonging to the floating area is marked as the standard segment, and then the overall proportion Zb of the standard segment in the entire voltage change curve is determined, where Zb = standard segment line length ÷ total line length of the voltage change curve, and whether Zb satisfies: Zb>90%:

[0041] If yes, it means that the flow battery has passed the test, and a constant current test pass signal is generated;

[0042] If not, it means that the initial test of this flow battery fails, and the subsequent voltage evaluation terminal is executed to perform subsequent voltage numerical analysis;

[0043] Specifically, the reason for determining the corresponding floating area is to make the assessment standard have a corresponding floating range. The relevant line segments within the corresponding floating range are considered to be up to standard, and some line segments outside the corresponding floating range are considered to be unsatisfactory. In this way, during the initial inspection, the comprehensiveness of the inspection can be guaranteed, thereby ensuring the overall inspection and assessment effect.

[0044] Among them, the voltage assessment end, for the situation that the liquid flow battery fails the initial test, first determines the voltage parameter corresponding to the liquid flow battery at the time of charging completion, checks the voltage parameter with the preset standard range, and determines the subsequent execution end based on the specific verification result. Specifically, first, the liquid flow battery at this moment does not meet the standard in the initial inspection, so in order to identify the corresponding specific reasons for non-compliance, voltage analysis is prioritized. If the voltage standard is up to standard, then its voltage curve cannot meet the corresponding assessment conditions due to numerical fluctuations. Then the electrolyte concentrations of the two different areas (positive electrode area and negative electrode area) inside the liquid flow battery are different, which will cause related fluctuations in the voltage parameters during the charging process. For other voltage conditions, different execution ends need to be executed;

[0045] Among them, the specific method of checking the voltage parameters with the standard range is:

[0046] The voltage parameter of the flow battery at the time of charging completion is calibrated as DY, and the voltage parameter DY is checked with the preset standard interval, wherein the endpoint values ​​of the standard interval are all preset values, and the specific values ​​are determined by the operator based on experience;

[0047] If DY∈standard interval, it means that after charging, there is no problem with the voltage parameter of this flow battery. Then the voltage parameter is related to the electrolyte concentration. If the verification result does not meet the standard, it means that the flow battery fluctuates violently during charging. Then, the electrolyte vanadium ion concentration in the two areas is likely to be greatly different. In order to identify such a situation, the concentration difference assessment terminal is executed;

[0048] If DY>standard interval (that is, DY is greater than the maximum value of the standard interval), it means that the voltage of this flow battery is overcharged after charging. For such a situation, it is related to the fact that the vanadium ion concentration of the electrolyte inside the flow battery is higher than the standard concentration, which will cause the voltage parameter to be too high compared to the standard interval after charging. When the vanadium ion concentration of such electrolyte is too high, the charging rate will be slow. Then, the charging rate analysis terminal can be used to analyze the charging rate to lock such abnormal situation.

[0049] If DY < standard interval (that is, DY is less than the minimum value of the standard interval), it means that the voltage of the flow battery is too low after charging. In this case, the vanadium ion concentration of the electrolyte in the corresponding flow battery is too low. This low concentration will cause the flow battery to discharge faster. In this case, the discharge test end can be used to analyze the discharge time and lock this abnormal situation.

[0050] Among them, the concentration difference assessment end uses rays of specified wavelength to perform refraction analysis on the electrolyte in two different areas of the flow battery (flow batteries are generally large in size, and this type of test process is carried out during the factory inspection stage, so refraction analysis can be performed based on the corresponding rays to identify whether the refraction angles are consistent), identify the refraction angles of the two different areas, and then based on the specific difference in the refraction angle values ​​of the two, assess whether the electrolyte concentration in the positive and negative electrode areas of the flow battery is abnormal. The specific method of conducting the assessment is:

[0051] Use designated equipment to generate rays of designated wavelengths to perform refraction analysis on the positive and negative electrode areas of the flow battery, and the irradiation angles of the rays and the electrolyte on the surfaces of the corresponding positive and negative electrode areas are consistent, identify the refraction angles of the rays, calibrate the refraction angles generated in the positive electrode area as Z1, and calibrate the refraction angles generated in the negative electrode area as Z2, where the selection methods of the refraction angles in the two positive and negative electrode areas are consistent;

[0052] Identify whether Z1 and Z2 satisfy: |Z1-Z2|>Y1. If so, generate abnormal concentration signals in the positive and negative electrode regions and display them directly for external personnel to view. If not, generate a test error signal for display for external personnel to view. When external personnel identify the test error signal, human intervention is required to assess the specific abnormal situation of the flow battery. Specifically, the refractive index of the electrolyte is affected by its concentration; this is because the dielectric constant and solvation structure of the electrolyte change with the change of solute concentration; when the solute concentration changes, the optical properties of the solution will also change accordingly, resulting in a change in the refractive index; experimental studies have shown that there is an approximate linear relationship between the refractive index of NaCl solution and its concentration; as the concentration of NaCl solution increases, its refractive index also increases accordingly.

[0053] The charging rate analysis end generates a charging rate change curve for different charging rates corresponding to different times in the charging stage, and then identifies whether the electrolyte concentration in the flow battery exceeds the standard based on the value change of the charging rate change curve. The specific method of identification is as follows:

[0054] Based on the different charging rates generated at different times, a charging rate change curve is generated. The horizontal coordinate of the change curve is the time line, and the vertical coordinate is the charging rate. The charging rate is the amount of charge generated per unit time, that is, the charging current. The end time of this charging stage is the time when the voltage rise value is lower than the preset value X1 and charging is stopped;

[0055] Confirm the location of the constant current in the coordinate system where the charging rate change curve is located, and construct a set of vertical lines perpendicular to this position, and mark the vertical lines as standard lines. Based on the confirmed charging rate change curve, mark the part of the line segments below the standard line as lower segments, and mark the part of the line segments above the standard line as upper segments. The constant current is the standard charging value per unit time, which is a preset value prepared in advance by the operator. Then determine the initial endpoint and the terminal endpoint of the charging rate change curve, construct a set of range lines passing through the initial endpoint and perpendicular to the standard line, and then construct a set of range lines passing through the terminal endpoint and perpendicular to the standard line;

[0056] Based on the determined range line and the charging rate change curve, the range area generated between the lower segment and the charging rate change curve is confirmed and the area parameter of the range area is calibrated as M1. Similarly, the area parameter M2 of the range area between the upper segment and the charging rate change curve is confirmed;

[0057] If M2>M1, it means that the area of ​​the lower segment is larger, and simultaneously it means that the time of slow charging rate is longer, which means that the charging rate of this liquid flow battery is too slow, and a liquid flow battery concentration exceeding standard signal is generated and displayed directly for external personnel to view. If M2≤M1, a test error signal is generated and displayed for external personnel to view.

[0058] Among them, at the discharge test end, the liquid flow battery is subjected to constant current discharge treatment, and its discharge duration is recorded to assess whether the electrolyte concentration of the liquid flow battery is too low. The specific method of conducting the assessment is:

[0059] Based on the constant current discharge process of this flow battery, its specific discharge duration is locked and calibrated as T1;

[0060] The discharge time T1 is compared with the preset minimum standard time Ts: if T1 < Ts, a low flow battery concentration signal is generated; if T1 ≥ Ts, a test error signal is generated for display for external personnel to view, where Ts is a preset value, and its specific value is determined in advance by the operator based on experience.

[0061] Some of the data in the above formulas are dimensionless and numerically calculated. Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0062] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A flow battery testing system, characterized in that: include: The constant current test end uses a standard constant current to charge the flow battery, and generates a voltage change curve in real time based on the voltage change of the flow battery. When the voltage rise value per unit time is lower than the preset value X1, the charging is stopped, and the generated voltage change curve is transmitted to the constant current data verification end; The constant current data verification end compares the generated voltage change curve with the standard curve preset in the standard database, identifies the specific proportion parameters of the corresponding standard line segment in the voltage change curve, and determines whether the liquid flow battery meets the initial test standards based on the specific proportion analysis results. The specific method is as follows: Based on the determined standard curve, the initial point and the end point of the standard curve remain unchanged, and other points inside the standard curve are translated up and down, and the translation distance is Y1, where Y1 is a preset value. Based on the specific translation process of several points inside the standard curve, the floating area of ​​the upper and lower standards is locked; Based on the determined floating area, the line segment in the voltage change curve belonging to the floating area is marked as the standard segment, and then the overall proportion Zb of the standard segment in the entire voltage change curve is determined, where Zb = standard segment line length ÷ total line length of the voltage change curve, and whether Zb satisfies: Zb>90%: If so, a constant current test pass signal is generated; If not, it means that the initial test of this flow battery fails, and the subsequent voltage evaluation terminal is executed to perform subsequent voltage numerical analysis; The voltage assessment end, in case the liquid flow battery fails the initial test, first determines the voltage parameter corresponding to the liquid flow battery at the time of charging completion, checks the voltage parameter with the preset standard range, and determines the subsequent execution end based on the specific check result; The concentration difference assessment end uses rays of a specified wavelength to perform refraction analysis on the electrolyte in two different areas of the flow battery, identifies the refraction angles of the two different areas, and then assesses whether the electrolyte concentration in the positive and negative areas of the flow battery is abnormal based on the specific difference in the refraction angle values ​​of the two; The charging rate analysis end generates a charging rate change curve for different charging rates corresponding to different moments in this charging stage, and then identifies whether the electrolyte concentration in the flow battery exceeds the standard based on the value change of the charging rate change curve; At the discharge test end, the liquid flow battery is subjected to constant current discharge treatment, and its discharge time is recorded to assess whether the electrolyte concentration of the liquid flow battery is too low.

2. A flow battery testing system according to claim 1, characterized in that: The specific method for the voltage assessment end to check the voltage parameter with the standard range is: The voltage parameter of the flow battery at the time of charging completion is calibrated as DY, and the voltage parameter DY is checked with a preset standard interval, wherein the endpoint values ​​of the standard interval are all preset values; If DY∈standard interval, execute concentration difference assessment end; If DY>standard range, execute charging rate analysis terminal; If DY is less than the standard range, the discharge test is performed.

3. A flow battery testing system according to claim 2, characterized in that: The concentration difference assessment end assesses whether the electrolyte concentration in the positive and negative electrode regions of the flow battery is abnormal in the following specific manner: Use designated equipment to generate rays of designated wavelengths to perform refraction analysis on the positive and negative electrode areas of the flow battery, and the irradiation angles of the rays and the electrolyte on the surfaces of the corresponding positive and negative electrode areas are consistent, identify the refraction angles of the rays, calibrate the refraction angles generated in the positive electrode area as Z1, and calibrate the refraction angles generated in the negative electrode area as Z2, where the selection methods of the refraction angles in the two positive and negative electrode areas are consistent; Identify whether Z1 and Z2 satisfy: |Z1-Z2|>Y1. If so, generate abnormal concentration signals in the positive and negative regions. If not, generate a test error signal for display.

4. A flow battery testing system according to claim 2, characterized in that: The specific method of the charging rate analysis end for identifying whether the electrolyte concentration in the flow battery exceeds the standard is: Based on the different charging rates generated at different times, a charging rate variation curve is generated, where the charging rate is the amount of charge generated per unit time; Confirm the location of the constant current in the coordinate system where the charging rate change curve is located, and construct a set of vertical lines perpendicular to this position, mark the vertical lines as standard lines, and based on the confirmed charging rate change curve, mark the part of the line segments below the standard line as lower segments, and mark the part of the line segments above the standard line as upper segments, whose constant current is the standard charging value per unit time and is a preset value, then determine the initial endpoint and the terminal endpoint of the charging rate change curve, construct a set of range lines passing through the initial endpoint and perpendicular to the standard line, and then construct a set of range lines passing through the terminal endpoint and perpendicular to the standard line; Based on the determined range line and the charging rate change curve, the range area generated between the lower segment and the charging rate change curve is confirmed and the area parameter of the range area is calibrated as M1. Similarly, the area parameter M2 of the range area between the upper segment and the charging rate change curve is confirmed; If M2>M1, a flow battery concentration exceeding standard signal is generated; If M2≤M1, a check error signal is generated for display.

5. A flow battery testing system according to claim 2, characterized in that: The specific method of evaluating whether the electrolyte concentration of the flow battery is too low at the discharge test end is: Based on the constant current discharge process of this flow battery, its specific discharge duration is locked and calibrated as T1; The discharge time T1 is compared with the preset minimum standard time Ts: if T1 < Ts, a low flow battery concentration signal is generated; if T1 ≥ Ts, a test error signal is generated for display, where Ts is a preset value.

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