Method and apparatus for detecting flow within a flow battery stack

Abstract

This invention provides a method and apparatus for detecting the internal flow rate of a flow battery stack. The method includes: acquiring the voltage of a pair of detection points within a single cell of the stack under test, and calculating the voltage difference ΔV between the detection point pairs; obtaining the flow rate of each detection point pair based on the voltage difference ΔV, the stack current, and a comparison with a standard database, and calculating the flow rate Q1 of a single cell; and calculating the total flow rate Q of all single cells in the stack under test. 总 And calculate the average flow difference MD of the fuel cell stack under test. 堆 By comparing the average flow rate difference MD 堆 Whether the internal flow rate of the fuel cell stack under test is uniformly distributed is determined by checking if it exceeds a preset value S. The detection method provided by this invention collects the local voltage within a single cell and calculates the flow rate data within the single cell and the fuel cell stack, thereby achieving a quantitative and intuitive display of the flow rate distribution within and between individual cells of the fuel cell stack.

Description

Technical Field

[0001] This invention relates to the field of flow batteries, and more particularly to a method and apparatus for detecting the internal flow rate of a flow battery stack. Background Technology

[0002] In flow batteries, the stack flow rate is one of the core parameters determining its performance and efficiency. The flow rate directly affects the battery's power output, energy efficiency, and long-term operational stability.

[0003] First, a higher flow rate can quickly transport active materials to the electrode surface, enhancing the mass transfer process and thus improving the battery's instantaneous power output, avoiding polarization losses due to reactant depletion. However, a higher flow rate is not always better. Excessively high flow rates significantly increase pump losses, consume a large amount of auxiliary energy, and reduce the system's net efficiency; at the same time, it may accelerate the erosion of electrode materials, affecting module lifespan. Conversely, a flow rate that is too low will lead to the depletion of reactant concentration on the electrode surface, causing intensified concentration polarization, which not only limits power but may also trigger side reactions, affecting coulombic efficiency.

[0004] However, in actual engineering, due to factors such as flow channel design, uneven compression ratio of porous electrodes, assembly tolerances, and material deformation after long-term operation, the electrolyte is prone to uneven distribution inside the fuel cell stack. The ultimate macroscopic manifestations are: reduced overall output voltage of the fuel cell stack, decreased energy efficiency, accelerated capacity decay, and in severe cases, even safety issues such as local hydrogen evolution and permanent damage to electrode or membrane materials.

[0005] Currently, the internal flow distribution of flow batteries is obtained based on simulation results. However, this method relies on the precise setting of boundary conditions and physical property parameters, and its accuracy is difficult to verify directly through experiments. Furthermore, the simulation cannot reflect the real flow state of the battery in actual operation, especially under conditions of fluctuation or long-term operation such as flow channel blockage and deformation.

[0006] Therefore, developing a scheme that can transform flow distribution into an intuitive image or quantitative distribution to enable direct observation, diagnosis, and optimization of the flow field in flow batteries is of great significance for improving battery uniformity and extending battery life. Summary of the Invention

[0007] The main objective of this invention is to provide a method and apparatus for detecting the internal flow rate of a flow battery stack, in order to solve the problem in the prior art that the differences in flow rate distribution within and between individual cells of the stack cannot be quantitatively and intuitively displayed.

[0008] To achieve the above objectives, a first aspect of the present invention provides a method for detecting the internal flow rate of a flow battery stack, comprising the following steps: Step S100: Under the operating state of the stack under test, obtain the voltage of the detection point pair in a single cell of the stack under test, and calculate the voltage difference ΔV between the detection point pairs. Step S200: Based on the voltage difference ΔV, the stack current, and the comparison with the standard database, obtain the flow rate of each detection point pair, and calculate the flow rate Q1 of a single cell; Step S300: Calculate the total flow rate Q of all individual cells in the stack under test. 总 And calculate the average flow difference MD of the fuel cell stack under test. 堆 By comparing the average flow rate difference MD 堆 Whether the internal flow rate of the fuel cell stack under test is uniformly distributed is determined by checking whether it is greater than a preset value S.

[0009] The present invention provides a method for detecting the internal flow rate of a flow battery stack. By collecting the local voltage of multiple detection points inside a single cell under normal operating conditions, and calculating the flow rate data inside the single cell and the stack through the relationship between voltage and flow rate, the flow rate distribution within and between individual cells of the stack can be quantitatively and intuitively displayed. The uniformity of the flow rate distribution inside the stack can be directly determined by comparing the average difference of the flow rate of the stack with a preset value.

[0010] In some embodiments, the detection point pair is disposed on the electrode of a single cell, including a first detection point and a second detection point arranged sequentially along the electrolyte flow direction; Optionally, the number of detection point pairs is 5-50; Optionally, the center distance between two adjacent first detection points and the center distance L between two adjacent second detection points are each independently not less than 10cm.

[0011] In some embodiments, each of the first detection points independently includes a first detection point A disposed at the high potential end of the single cell and a first detection point B disposed at the corresponding position at the low potential end of the single cell; Optionally, each of the second detection points independently includes a second detection point A located at the high potential end of the single cell and a second detection point B located at the corresponding position at the low potential end of the single cell.

[0012] In some embodiments, in step S100, obtaining the voltage of the detection point pair within a single cell of the stack under test includes: Step S101: Acquire the first voltage at the first detection point; Step S102: Acquire the second voltage at the second detection point.

[0013] In some embodiments, in step S101, the method for acquiring the first voltage at the first detection point includes: Step S1011: Acquire the first electrical signal A at the first detection point A; Step S1012: Acquire the first electrical signal B at the first detection point B; Step S1013: Calculate the potential difference between the first electrical signal A and the first electrical signal B, which is the first voltage; Optionally, in step S102, the method for acquiring the second voltage at the second detection point includes: Step S1021: Acquire the second electrical signal A at the second detection point A; Step S1022: Acquire the second electrical signal B at the second detection point B; Step S1023: Calculate the potential difference between the second electrical signal A and the second electrical signal B, which is the second voltage.

[0014] In some embodiments, the method for obtaining the standard database in step S200 includes: Step S201: Under the operating state of the stack under test, obtain the voltage of the detection point pair in a single cell of the stack under test, and calculate the voltage difference ΔV between the detection point pairs. Step S202: Maintain the fuel cell stack under test in the operating state, adjust the fuel cell stack current and fuel cell stack flow rate, and collect the voltage difference of the detection point under different fuel cell stack currents and different fuel cell stack flow rates; Step S203: Establish the mapping relationship between the voltage difference and the stack current and stack flow rate.

[0015] In some embodiments, the relationship between the voltage difference and the stack current and stack flow rate is shown in equation (1). ΔV = (k × I) / Q, Equation (1); In equation (1), ΔV is the voltage difference between the detection point pairs, in units of V; I represents the fuel cell current, measured in amperes (A). Q represents the fuel cell stack flow rate, measured in L / min. k is the correlation coefficient, with units of Ω·L / min; Optionally, k is 1×10 -5 -10×10 -5 .

[0016] In some embodiments, the preset value S is not greater than 0.005; Optionally, the method for determining whether the internal flow distribution of the test stack is uniform includes: The average difference in flow rate MD 堆 If the value is greater than the preset value S, it is determined that the internal flow distribution of the fuel cell stack under test is uneven. The average difference in flow rate MD 堆 If the value is not greater than the preset value S, it is determined that the internal flow distribution of the fuel cell stack under test is uniform.

[0017] A second aspect of the present invention provides a device for detecting the internal flow rate of a vanadium redox flow battery, applied to the detection method described in the first aspect, comprising: A voltage detection module includes a terminal block, a wire, and a conductive sheet disposed on the detection point pair. One end of the wire is connected to the conductive sheet, and the other end is provided with the terminal block. The conductive sheet is used to detect the voltage signal of the detection point pair within a single cell. A voltage acquisition module is connected to the voltage detection module via the terminal block. The voltage acquisition module is used to convert the voltage signal into a digital signal that can be recognized by the signal processing module and transmit it to the signal processing module. A signal processing module, which is connected to the voltage acquisition module, is used to receive digital signals transmitted by the voltage acquisition module.

[0018] In some embodiments, the conductive sheet has a thickness of not less than 0.1 mm and an area of ​​not less than 1 cm². 2 ; Optionally, the conductive sheet is a metal conductive sheet; Optionally, the conductive sheet is selected from any one of titanium sheet, platinum sheet, and gold sheet; Optionally, the voltage acquisition module may be a voltage acquisition module with 48 or more channels.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 This is a schematic flowchart of the method for detecting the internal flow rate of the flow battery stack according to the present invention.

[0022] Figure 2 This is a schematic diagram of the process for obtaining a standard database in the method for detecting the internal flow rate of a flow battery stack according to the present invention.

[0023] Figure 3This is a schematic diagram of the internal flow detection device for the vanadium redox flow battery of the present invention.

[0024] Figure 4 This is a schematic diagram of the internal flow detection device for the vanadium redox flow battery of the present invention.

[0025] Figure 5 This is a schematic diagram of the internal flow detection device for the vanadium redox flow battery of the present invention.

[0026] Figure 6 This is a schematic diagram of the voltage detection module in the vanadium redox flow battery internal flow detection device of the present invention.

[0027] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0030] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0031] As mentioned above, refer to Figure 1-6 As shown, the first aspect of the present invention provides a method for detecting the internal flow rate of a flow battery stack, comprising the following steps: Step S100: Under the operating state of the stack under test, obtain the voltage of the detection point pair in a single cell of the stack under test, and calculate the voltage difference ΔV between the detection point pairs. Step S200: Based on the voltage difference ΔV, the stack current, and the comparison with the standard database, obtain the flow rate of each detection point pair, and calculate the flow rate Q1 of a single cell; Step S300: Calculate the total flow rate Q of all individual cells in the stack under test.总 And calculate the average flow difference MD of the fuel cell stack under test. 堆 By comparing the average flow rate difference MD 堆 Whether the internal flow rate of the fuel cell stack under test is uniformly distributed is determined by checking whether it is greater than a preset value S.

[0032] The present invention provides a method for detecting the internal flow rate of a flow battery stack. By collecting the local voltage of multiple detection points inside a single cell under normal operating conditions, and calculating the flow rate data inside the single cell and the stack through the relationship between voltage and flow rate, the flow rate distribution within and between individual cells of the stack can be quantitatively and intuitively displayed. The uniformity of the flow rate distribution inside the stack can be directly determined by comparing the average difference of the flow rate of the stack with a preset value.

[0033] It should be noted that before conducting the tests, the fuel cell stack must first undergo an airtightness test. Only after passing the airtightness test can the method of this invention be used to detect the internal flow rate of the fuel cell stack. In this invention, the sum of the flow rates Q1 of all individual cells within the fuel cell stack under test is the total flow rate Q of the fuel cell stack under test. 总 Furthermore, depending on the actual situation such as the number of individual cells in the fuel cell stack and the detection capability, the present invention can either obtain the voltage data of all individual cell detection point pairs in the fuel cell stack under test at once, or obtain the flow rate of individual cell detection point pairs in the fuel cell stack under test in multiple steps.

[0034] In some embodiments, the detection point pair is disposed on the electrode of a single cell, including a first detection point and a second detection point arranged sequentially along the electrolyte flow direction.

[0035] It should be noted that the detection points in this invention are set on the electrodes of a single cell, including a first detection point and a second detection point, which are correspondingly located at the electrolyte inlet and outlet positions. The voltage difference ΔV between the detection point pairs refers to the absolute value of the voltage difference between the detection point pairs. When the battery stack under test is in a charging operation state, the voltage at the outlet position is greater than the voltage at the inlet position, and the voltage difference ΔV is the difference between the voltage at the outlet position and the voltage at the inlet position. When the battery stack under test is in a discharging operation state, the voltage at the inlet position is greater than the voltage at the outlet position, and the voltage difference ΔV is the difference between the voltage at the inlet position and the voltage at the outlet position.

[0036] In some embodiments, the number of detection point pairs is 5-50.

[0037] To better visualize the flow distribution within the fuel cell stack, 5-50 detection points are evenly distributed across the electrodes, enabling the detection of localized voltages at different locations on the electrodes. For example... Figures 2-3As shown, in some embodiments, the center distance L between two adjacent first detection points and the center distance L between two adjacent second detection points are each independently not less than 10cm. A reasonable distance design is a crucial foundation for ensuring accurate sensing of the battery's internal state, achieving precise management, and providing safety warnings. If the center distance between adjacent detection points is too small, the voltage difference between them will be very weak, failing to reflect the true potential change trend and leading to electric field overlap, rendering the measurement data meaningless. This invention sets the center distance L between two adjacent detection points at the liquid outlet position to be no less than 10cm, and the center distance L between two adjacent detection points at the liquid inlet position to be no less than 10cm, thus avoiding the problem of electric field overlap caused by excessively close placement.

[0038] In some embodiments, each of the first detection points independently includes a first detection point A disposed at the high potential end of the single cell and a first detection point B disposed at the corresponding position at the low potential end of the single cell.

[0039] In some embodiments, each of the second detection points independently includes a second detection point A disposed at the high potential end of the single cell and a second detection point B disposed at the corresponding position at the low potential end of the single cell.

[0040] It should be noted that voltage is the potential difference between two points in a circuit. In this invention, the voltage values ​​at the liquid inlet and outlet detection points are actually the potential difference between detection points with different potentials. Specifically, the high-potential end of the single cell in this invention refers to the positive electrode potential of the vanadium battery, while the low-potential end refers to the negative electrode potential. Therefore, the voltage value at a certain detection point in this invention is the difference between the positive and negative electrode potentials at that point.

[0041] In some embodiments, in step S100, obtaining the voltage of the detection point pair within a single cell of the stack under test includes: Step S101: Acquire the first voltage at the first detection point; Step S102: Acquire the second voltage at the second detection point.

[0042] In some embodiments, in step S101, the method for acquiring the first voltage at the first detection point includes: Step S1011: Acquire the first electrical signal A at the first detection point A; Step S1012: Acquire the first electrical signal B at the first detection point B; Step S1013: Calculate the potential difference between the first electrical signal A and the first electrical signal B, which is the first voltage.

[0043] In some embodiments, in step S102, the method for acquiring the second voltage at the second detection point includes: Step S1021: Acquire the second electrical signal A at the second detection point A; Step S1022: Acquire the second electrical signal B at the second detection point B; Step S1023: Calculate the potential difference between the second electrical signal A and the second electrical signal B, which is the second voltage.

[0044] like Figure 2 As shown, in some embodiments, the method for obtaining the standard database in step S200 includes: Step S201: Under the operating state of the stack under test, obtain the voltage of the detection point pair in a single cell of the stack under test, and calculate the voltage difference ΔV between the detection point pairs. Step S202: Maintain the fuel cell stack under test in the operating state, adjust the fuel cell stack current and fuel cell stack flow rate, and collect the voltage difference of the detection point under different fuel cell stack currents and different fuel cell stack flow rates; Step S203: Establish the mapping relationship between the voltage difference and the stack current and stack flow rate.

[0045] In this embodiment of the invention, the implementation process of step S202 includes: Step S2021: Maintain the test stack in the operating state and obtain the voltage difference of the same detection point in a single cell of the test stack under different stack currents; Step S2022: Maintain the test stack in operation and obtain the voltage difference of the same detection point in a single cell of the test stack under different stack flow rates.

[0046] It should be noted that during the implementation of the above steps, the stack current can be fixed by constant current charging or discharging, and the stack flow rate can be controlled by a closed-loop strategy.

[0047] In this embodiment of the invention, the implementation process of step S203 includes: Step S2031: Establish the mapping relationship between voltage difference and stack current; Step S2032: Establish the mapping relationship between voltage difference and stack current; Step S2033: Establish the mapping relationship between voltage difference and stack current and stack flow rate.

[0048] In some embodiments, the mapping relationship between the voltage difference and the stack current and stack flow rate is shown in equation (1). ΔV = (k × I) / Q, Equation (1); In equation (1), ΔV is the voltage difference between the detection point pairs, in units of V; I represents the fuel cell current, measured in amperes (A). Q represents the fuel cell stack flow rate, measured in L / min. k is the correlation coefficient, with units of Ω·L / min.

[0049] In some embodiments, k is 1×10 -5 -10×10 -5 .

[0050] In some embodiments, the preset value S is not greater than 0.005.

[0051] In some embodiments, a method for determining whether the internal flow rate of the test stack is uniformly distributed includes: The average difference in flow rate MD 堆 If the value is greater than the preset value S, it is determined that the internal flow distribution of the fuel cell stack under test is uneven. The average difference in flow rate MD 堆 If the value is not greater than the preset value S, it is determined that the internal flow distribution of the fuel cell stack under test is uniform.

[0052] The method provided by this invention can also detect the flow distribution at different locations within a single unit. In some embodiments, step S200 further includes: Step S204: Based on the mapping relationship between the voltage difference ΔV and the stack current and stack flow rate, obtain the flow rate of each detection point pair, and calculate the average flow rate difference of a single cell; Step S205: By comparing whether the average flow difference of the single cell is greater than a preset value S, it is determined whether the internal flow of the single cell is uniformly distributed.

[0053] It should be noted that the method for determining whether the internal flow of a single cell is uniformly distributed is the same as the method for determining the internal flow of a fuel cell stack, and will not be described in detail here.

[0054] As mentioned above, refer to Figures 3-6 A second aspect of the present invention provides a device for detecting the internal flow rate of a vanadium redox flow battery, applied to the detection method described in the first aspect, comprising: The voltage detection module 100 includes a terminal block 101, a wire 102, and a conductive sheet 103 disposed on the detection point pair. One end of the wire 102 is connected to the conductive sheet 103, and the other end is provided with the terminal block 101. The conductive sheet 103 is used to detect the voltage signal of the detection point pair in a single battery. The voltage acquisition module 200 is connected to the voltage detection module 100 through the terminal block 101. The voltage acquisition module 200 is used to convert the voltage signal into a digital signal that can be recognized by the signal processing module and transmit it to the signal processing module 300. The signal processing module 300 is connected to the voltage acquisition module 200 and is used to receive the digital signal transmitted by the voltage acquisition module 200.

[0055] The detection device provided by this invention has a simple structure and is easy to install. By adding a voltage detection module and a voltage acquisition module to the traditional fuel cell stack structure, the voltage difference at different detection points can be obtained, which can intuitively display the flow differences within and between individual cells.

[0056] It should be noted that, in order to better install the voltage detection module inside the fuel cell stack, the present invention can add a groove matching the wire on the surface of the fuel cell stack fluid flow frame, which facilitates the wiring of the voltage detection module; at the same time, the present invention can also process grooves on the electrode surface for placing the conductive sheet, which facilitates the placement of the conductive sheet.

[0057] like Figure 5 and Figure 6 As shown, in some embodiments, the conductive sheet 103 has a thickness of not less than 0.1 mm and an area of ​​not less than 1 cm². 2 .

[0058] In some embodiments, the conductive sheet 103 is a metallic conductive sheet. The present invention does not have special requirements for the material of the conductive sheet, as long as it is conductive and corrosion-resistant. Materials known in the art can be used as the conductive sheet. More preferably, the conductive sheet is selected from any one of titanium, platinum, and gold sheets.

[0059] It should be noted that the present invention does not have any special requirements on the material of the conductor. Materials known in the art can be used. For example, the present invention uses titanium wire or platinum wire as the conductor, and the surface of the conductor can also be coated with a polyurethane-based corrosion-resistant and insulating material.

[0060] Because this invention collects a large amount of data, in some embodiments, the voltage acquisition module 200 uses a voltage acquisition module with 48 or more channels. This invention connects the voltage detection module and the voltage acquisition module sequentially. To facilitate detection and reduce wiring complexity, the positive and negative voltages at the same detection point are connected to adjacent points on the voltage acquisition module, and the voltages at the inlet and outlet positions are also connected to adjacent points on the voltage acquisition module. This wiring method allows for a more intuitive display of the voltage at the same detection point.

[0061] It should be noted that during voltage data acquisition, to ensure accuracy, the acquisition interval can be set within the range of 0.5-1 second. At the start of the test, pay attention to the rationality of the data and rule out data anomalies caused by abnormal acquisition data or channel malfunctions; in this invention, the voltage acquisition module's accuracy range should be set to 2V, with an accuracy of 0.5%, and the test data should be accurate to 0.001V.

[0062] In this embodiment of the invention, a fuel cell stack with an output power of 10 kW was tested. The stack flow rate was 34 L / min, the stack current was 320 A, and the correlation coefficient k was (1.4 ± 0.2) × 10⁻⁶. -5 Ω·L / min; the stack contains 25 individual cells, with 8 detection point pairs set at the positive electrode of each cell, including 8 first detection points A at the positive electrode inlet and 8 second detection points B at the positive electrode outlet; and 8 detection point pairs set at the negative electrode, including 8 first detection points B at the negative electrode inlet and 8 second detection points B at the negative electrode outlet. The center distance L between two adjacent detection points is 10cm; a wiring groove with a depth of 0.5mm is reserved on the flow frame; the outer diameter of the wire is 0.5mm, the conductive sheet is made of titanium sheet (10×10×0.2mm), and the wire is made of polyurethane-coated titanium wire; the electrode is made of carbon felt, which is laser-etched to depths of 0.5mm and 2mm respectively. After the wire is installed, the titanium sheet is covered again with 1.8mm carbon felt; the wire is connected to the voltage acquisition module through the wiring terminal, and 9 voltage acquisition modules with 48 channels are used for signal transmission. Taking this as an example, the implementation process of the above detection method will be explained, specifically including the following: Step S100: Use a constant 200mA / cm 2 Under charging conditions with a SOC of 50% and a temperature of 35℃, the voltages of eight detection point pairs in the first single cell (V1) of the stack under test were acquired, and the voltage difference ΔV between the eight detection point pairs was calculated. V1-1 represents the first detection point in the first single cell, where V1-1-1 is the voltage at the liquid outlet position, V1-1-2 is the voltage at the liquid inlet position, and so on. Under charging conditions, the voltage difference between the detection point pairs is the difference between the voltage at the liquid outlet position and the voltage at the liquid inlet position at the same location. Specific detection data are shown in Table 1. Table 1

[0063] Step S200: Based on the voltage difference ΔV, the stack current, and the comparison with the standard database, the flow rate of the 8 detection sites in the first single cell is obtained. The specific data is shown in Table 2. Table 2

[0064] The sum of the flow rates at the eight detection sites in the table above is the flow rate of the single cell, Q1 = 1.3592 L / min. The average flow rate difference within the single cell is 0.00095, while the preset value S is 0.005. The fact that the average flow rate difference within the single cell is less than the preset value S indicates that the flow rate distribution within the single cell is uniform and the flow field design is reasonable.

[0065] Step S300: Detect the remaining 24 single cells according to the aforementioned detection method to obtain the flow rate of each single cell. The specific results are shown in Table 3.

[0066] Table 3

[0067] The total flow rate of the fuel cell stack, calculated from the data in the table above, is 33.87 L / min, with an average flow rate difference of 0.00148, which is significantly smaller than the preset value S. This indicates that the flow rate difference between individual cells within the fuel cell stack is small, and the flow rate distribution within the stack is uniform. Furthermore, the total flow rate of the fuel cell stack obtained using the detection method of this invention is very close to the actual flow rate, demonstrating that the flow rate calculated by the method provided by this invention is accurate and can effectively and intuitively display the flow rate distribution within the fuel cell stack.

[0068] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0069] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for detecting the internal flow rate of a flow battery stack, characterized in that, Includes the following steps: Step S100: Under the operating state of the stack under test, obtain the voltage of the detection point pair in a single cell of the stack under test, and calculate the voltage difference ΔV between the detection point pairs. Step S200: Based on the voltage difference ΔV, the stack current, and the comparison with the standard database, obtain the flow rate of each detection point pair, and calculate the flow rate Q1 of a single cell; Step S300: Calculate the total flow rate Q of all individual cells in the stack under test. 总 And calculate the average flow difference MD of the fuel cell stack under test. 堆 By comparing the average flow rate difference MD 堆 Whether the internal flow rate of the fuel cell stack under test is uniformly distributed is determined by checking whether it is greater than a preset value S.

2. The detection method according to claim 1, characterized in that, The detection points are set on the electrodes of the single cell, including a first detection point and a second detection point arranged sequentially along the electrolyte flow direction. Optionally, the number of detection point pairs is 5-50; Optionally, the center distance between two adjacent first detection points and the center distance L between two adjacent second detection points are each independently not less than 10cm.

3. The detection method according to claim 2, characterized in that, Each of the first detection points independently includes a first detection point A set at the high potential end of the single cell and a first detection point B set at the corresponding position at the low potential end of the single cell; Optionally, each of the second detection points independently includes a second detection point A located at the high potential end of the single cell and a second detection point B located at the corresponding position at the low potential end of the single cell.

4. The detection method according to claim 2, characterized in that, In step S100, obtaining the voltage of the detection point pair within a single cell of the stack under test includes: Step S101: Acquire the first voltage at the first detection point; Step S102: Acquire the second voltage at the second detection point.

5. The detection method according to claim 4, characterized in that, In step S101, the method for acquiring the first voltage at the first detection point includes: Step S1011: Acquire the first electrical signal A at the first detection point A; Step S1012: Acquire the first electrical signal B at the first detection point B; Step S1013: Calculate the potential difference between the first electrical signal A and the first electrical signal B, which is the first voltage; Optionally, in step S102, the method for acquiring the second voltage at the second detection point includes: Step S1021: Acquire the second electrical signal A at the second detection point A; Step S1022: Acquire the second electrical signal B at the second detection point B; Step S1023: Calculate the potential difference between the second electrical signal A and the second electrical signal B, which is the second voltage.

6. The detection method according to claim 1, characterized in that, In step S200, the method for obtaining the standard database includes: Step S201: Under the operating state of the stack under test, obtain the voltage of the detection point pair in a single cell of the stack under test, and calculate the voltage difference ΔV between the detection point pairs. Step S202: Maintain the fuel cell stack under test in the operating state, adjust the fuel cell stack current and fuel cell stack flow rate, and collect the voltage difference of the detection point under different fuel cell stack currents and different fuel cell stack flow rates; Step S203: Establish the mapping relationship between the voltage difference and the stack current and stack flow rate.

7. The detection method according to claim 6, characterized in that, The relationship between the voltage difference and the stack current and stack flow rate is shown in equation (1). ΔV = (k × I) / Q, Equation (1); In equation (1), ΔV is the voltage difference between the detection point pairs, in units of V; I represents the fuel cell current, measured in amperes (A). Q represents the fuel cell stack flow rate, measured in L / min. k is the correlation coefficient, with units of Ω·L / min; Optionally, k is 1×10 -5 -10×10 -5 .

8. The detection method according to any one of claims 1-7, characterized in that, The preset value S is not greater than 0.005; Optionally, the method for determining whether the internal flow distribution of the test stack is uniform includes: The average difference in flow rate MD 堆 If the value is greater than the preset value S, it is determined that the internal flow distribution of the fuel cell stack under test is uneven. The average difference in flow rate MD 堆 If the value is not greater than the preset value S, it is determined that the internal flow distribution of the fuel cell stack under test is uniform.

9. A device for detecting the internal flow rate of a vanadium redox flow battery, characterized in that, The method applied to the detection method as described in any one of claims 1-8 includes: A voltage detection module includes a terminal block, a wire, and a conductive sheet disposed on the detection point pair. One end of the wire is connected to the conductive sheet, and the other end is provided with the terminal block. The conductive sheet is used to detect the voltage signal of the detection point pair within a single cell. A voltage acquisition module is connected to the voltage detection module via the terminal block. The voltage acquisition module is used to convert the voltage signal into a digital signal that can be recognized by the signal processing module and transmit it to the signal processing module. A signal processing module, which is connected to the voltage acquisition module, is used to receive digital signals transmitted by the voltage acquisition module.

10. The detection device according to claim 9, characterized in that, The conductive sheet has a thickness of not less than 0.1 mm and an area of ​​not less than 1 cm². 2 ; Optionally, the conductive sheet is a metal conductive sheet; Optionally, the conductive sheet is selected from any one of titanium sheet, platinum sheet, and gold sheet; Optionally, the voltage acquisition module may be a voltage acquisition module with 48 or more channels.

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