Precision verification device and verification method of multichannel impedance measuring instrument for electrolytic cell

Abstract

The invention discloses a precision verification device and a precision verification method of a multichannel impedance measuring instrument for an electrolytic cell. The verification device comprises a power supply module, an electronic load module, an electrolytic bath impedance simulation module, a loop current measurement module and a response voltage measurement module. The verification method adopts the verification device. The beneficial effects of the application are that the DC power supply module, the high-bandwidth energy consumption type electronic load and the electrolytic cell impedance simulation module are combined to form a closed loop verification loop, the loop structure is consistent with a power level measurement scheme of an actual high-power electrolytic cell, the power level simulation capability is provided, and the credibility is high. In addition, precision verification can be carried out on all channels of the multi-channel impedance measuring instrument at the same time, and precision verification of single channels one by one is not needed. The modular structure can be conveniently integrated on an existing measurement platform, the verification process is simplified, the consistency and repeatability of test results are improved, and reliable guarantee is provided for regular precision verification and precision drift prevention of the PEM electrolytic cell.

Description

Technical Field

[0001] This application belongs to the field of water electrolysis hydrogen production technology, specifically relating to an accuracy verification device and method for a multi-channel impedance measuring instrument for an electrolyzer. Background Technology

[0002] With the widespread application of proton exchange membrane (PEM) electrolyzers in green hydrogen production, the dynamic characteristics of their internal electrochemical processes are attracting increasing attention. Electrochemical impedance spectroscopy (EIS), as a powerful tool for revealing electrode reaction kinetics, electrolyte mass transfer behavior, and interfacial processes, can acquire the impedance response characteristics of electrochemical systems over a wide frequency range. This provides quantitative evidence for optimizing catalyst formulations, improving flow channel design to enhance proton conduction efficiency, and reducing polarization losses. In-depth research on the impedance characteristics of PEM electrolyzers not only enables real-time monitoring of the electrolyzer's health status but also guides the optimization of system design and operation strategies, contributing to improved overall efficiency and extended equipment lifespan.

[0003] In the field of electrochemistry, electrochemical impedance spectroscopy is an important method for evaluating electrode interface processes and electrolytic cell performance, mainly including two technical routes: potential scanning and current perturbation. Potential scanning typically utilizes a frequency response analyzer (FRA) in conjunction with an electrochemical workstation. A small-amplitude sinusoidal potential excitation is superimposed on the steady-state potential, and the current response is recorded to calculate the impedance spectrum. Current perturbation involves applying an alternating current perturbation from a constant current source, using the potential change to infer the impedance characteristics. Currently, electrolytic cell applications are developing towards larger areas (high current) and multi-layer stacks (high voltage), and impedance measurements are also expanding towards multi-channel parallel measurement. With the widespread application of multi-channel parallel impedance measurement systems, the same measuring instrument can simultaneously perform impedance tests on multiple electrolytic cell chambers or multiple reaction zones, improving the resolution of measurement analysis and refining the evaluation of electrolytic cell performance. However, during long-term operation, the measurement accuracy of multi-channel impedance measuring instruments may decrease due to factors such as amplifier gain drift, changes in frequency response characteristics, and component aging. If the system accuracy is not periodically verified, the accumulation of errors will inevitably affect the reliability and repeatability of experimental results.

[0004] Existing methods for verifying the accuracy of impedance measuring instruments (such as electrochemical workstations) have two major problems: 1) They use signal-level measurement block diagrams, which differ greatly from the power-level measurement schemes of actual high-power electrolytic cells, making it difficult to conduct a comprehensive evaluation; 2) They only have a single channel-by-channel verification method, which requires connecting standard impedance units to each channel and conducting tests. This is not only cumbersome and time-consuming, but also difficult to meet the needs of rapid and batch accuracy evaluation when there are a large number of channels.

[0005] In summary, for the periodic accuracy verification of multi-channel impedance measurement systems, there is an urgent need for a verification method and device that features consistent measurement loops, simple structure, convenient operation, and batch verification capability. This would effectively reduce the time and manpower required for verification while ensuring measurement accuracy, and meet the actual needs of fields such as proton exchange membrane electrolyzers for periodic performance verification of multi-channel impedance measurement systems. Summary of the Invention

[0006] The purpose of this application is to provide an accuracy verification device and method for a multi-channel impedance meter for electrolytic cells. The device uses an impedance unit to simulate the object under test. By constructing a structure consistent with the impedance measurement circuit of the power level of the actual electrolytic cell, each channel independently collects voltage and current signals to calculate the impedance. The impedance results are cross-verified to realize the accuracy verification of the multi-channel impedance meter. It has the characteristics of compact structure, simple connection method and easy implementation.

[0007] This application addresses the following issues: For the periodic accuracy verification of multi-channel impedance measurement systems, there is an urgent need for a verification method and device that features consistent measurement loops, a simple structure, convenient operation, and batch verification capabilities. This would effectively reduce the time and manpower required for verification while ensuring measurement accuracy, thus meeting the practical needs of proton exchange membrane electrolyzers and other fields for the periodic performance verification of multi-channel impedance measurement systems.

[0008] The objective of this application is achieved through the following technical solution: A device for verifying the accuracy of a multi-channel impedance meter for an electrolytic cell includes a power supply module, an electronic load module, an electrolytic cell impedance simulation module, a loop current measurement module, and a response voltage measurement module. The positive terminal of the power supply module is connected to the positive terminal of the electronic load module, the negative terminal of the electronic load module is connected to the positive terminal of the electrolytic cell impedance simulation module, the negative terminal of the electrolytic cell impedance simulation module is connected to the positive terminal of the loop current measurement module, the negative terminal of the loop current measurement module is connected to the negative terminal of the power supply module, the positive terminal of the response voltage measurement module is connected to the positive terminal of the electrolytic cell impedance simulation module, and the negative terminal of the response voltage measurement module is connected to the negative terminal of the electrolytic cell impedance simulation module.

[0009] Furthermore, the electronic load module is a high-bandwidth, energy-efficient electronic load with an interface for external current disturbance control, and the current disturbance bandwidth is not less than 10kHz.

[0010] Furthermore, the loop current measurement module is a high-bandwidth current sensor with a measurement bandwidth of not less than 100kHz.

[0011] Furthermore, the verification device has N impedance measurement channels, including one current signal acquisition channel and N response voltage signal acquisition channels.

[0012] Furthermore, the current signal acquisition channel acquires the output value of the loop current measurement module; the electrolytic cell impedance simulation module is composed of N minus one standard RC module connected in series, N minus one response voltage signal acquisition channel acquires the terminal voltage of N minus one standard RC module respectively, and one response voltage signal acquisition channel acquires the total voltage of the electrolytic cell impedance simulation module.

[0013] Furthermore, the positive terminal of standard RC module one is connected to the positive terminal of the electronic load module, the negative terminal of standard RC module one is connected to the positive terminal of standard RC module two, the negative terminal of standard RC module two is connected to the positive terminal of standard RC module three, and so on. Finally, the positive terminal of standard RC module N minus one is connected to the negative terminal of standard RC module N minus two, and the negative terminal of standard RC module N minus one is connected to the positive terminal of the loop current measurement module.

[0014] Furthermore, the structure within a standard RC module is as follows: resistor R1 is connected in parallel with capacitor C1, denoted as R1 / / C1; resistor R2 is connected in parallel with capacitor C2, denoted as R2 / / C2; and resistor R3 is connected in series with R1 / / C1 and R2 / / C2 in sequence.

[0015] A method for verifying the accuracy of a multi-channel impedance meter for an electrolytic cell, employing the aforementioned accuracy verification device for a multi-channel impedance meter for an electrolytic cell, further includes the following verification steps: Step 1: After the multi-channel impedance meter is connected to the accuracy verification device, set the power supply module to constant voltage working mode and the electronic load module to constant current working mode controlled by external signal. Step 2, the frequency range of impedance measurement is: f high to f low The frequencies decreased sequentially, and a total of [number] measurements were taken. C The frequency point, the first i The frequency of each frequency point is denoted as f _ i , i =(1,2,3,… C ), initialized to i =1; Step 3: Provide the current signal of the electronic load module. The current signal is a mixture of AC and DC, and the frequency of the AC signal is... f_i The amplitude of the AC signal shall not exceed the amplitude of the DC signal; Step 4, the multi-channel impedance meter under test acquires the current measurement module of the acquisition loop and the response voltage measurement module. N Calculate the corresponding frequency for each signal. f_i The AC impedance is denoted as . , k =(1,2,3,… N ), indicating the first iChannel at each frequency point k impedance, Indicates the first i Channel at each frequency point k The real part of the impedance, Indicates the first i Channel at each frequency point k The imaginary part of the impedance; where, k =(1,2,3,… N- When 1), it represents the impedance of a single standard RC module. k = N When, it represents the total impedance of all standard RC modules; Step 5, within the frequency range to be measured, i = i +1, repeat steps 3 and 4 until... i = C , get all C Under each frequency point N The AC impedance value of each channel.

[0016] Step 6, at the same frequency f_i Below, the impedance vectors of each individual standard RC module are added together in the complex plane to obtain a composite impedance vector; the real part of this composite vector is... The imaginary part is ; Step 7: Define the evaluation index channel superposition relative error CIRE The relative error of the real part is denoted as . CIRE real The relative error of the imaginary part is denoted as CIRE imag This is used to measure the relative error between the combined impedance vector after multi-channel superposition and the total impedance vector. The relative errors of the real and imaginary parts are calculated as follows: (1); (2); in, Indicates taking the absolute value; Step 8: Calculate the real part of the measured impedance of each module. virtual part With the real part of the total impedance virtual part Substitute into formulas (1) and (2) to perform verification and judgment.

[0017] Furthermore, in step 8, it is stipulated that if CIRE real , CIRE imagIf the values ​​are all less than 1%, it indicates that the simultaneous measurement of multiple channels has good consistency and passes the verification; otherwise, the verification fails and each channel needs to be recalibrated.

[0018] The beneficial effects of this application are as follows: By combining a DC power supply module, a high-bandwidth energy-consuming electronic load, and an electrolytic cell impedance simulation module, a closed-loop verification circuit is formed. The circuit structure is consistent with the power level measurement scheme of an actual high-power electrolytic cell, possessing power level simulation capabilities and high reliability. Furthermore, it can simultaneously verify the accuracy of all channels of a multi-channel impedance meter, eliminating the need to verify the accuracy of each channel individually. The modular structure facilitates integration into existing measurement platforms, simplifying the verification process and improving the consistency and repeatability of test results, providing a reliable guarantee for the periodic accuracy verification of PEM electrolytic cells and preventing accuracy drift.

[0019] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of this application, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by this application, and will not be exhaustively listed here. Attached Figure Description

[0020] Figure 1 This is a block diagram of the topology of the verification device in this application.

[0021] Figure 2 This is a block diagram of the topology of the verification device of this application, which consists of six standard RC modules forming the verification circuit.

[0022] Figure 3 This is a schematic diagram of the connection of each component in the standard second-order RC circuit of the verification device in this application.

[0023] Figure 4 This is a comparison diagram of the segmented measurement impedance superposition and the overall measurement impedance vector of each standard RC module in Embodiment 2 of this application, taking a 100Hz frequency point as an example.

[0024] Figure 5 This is a comparison chart of the Nyquist plot of the impedance superposition and the overall measured impedance obtained from the multi-channel measurement of each standard RC module in Embodiment 2 of this application. Detailed Implementation

[0025] The following non-limiting embodiments are used to illustrate this application.

[0026] Example 1 refer to Figures 1-3As shown, an accuracy verification device for a multi-channel impedance meter for an electrolytic cell includes a power supply module 1, an electronic load module 2, an electrolytic cell impedance simulation module 3, a loop current measurement module 4, and a response voltage measurement module 5.

[0027] The positive terminal of power supply module 1 is connected to the positive terminal of electronic load module 2, the negative terminal of electronic load module 2 is connected to the positive terminal of electrolytic cell impedance simulation module 3, the negative terminal of electrolytic cell impedance simulation module 3 is connected to the positive terminal of loop current measurement module 4, the negative terminal of loop current measurement module 4 is connected to the negative terminal of power supply module 1, the positive terminal of response voltage measurement module 5 is connected to the positive terminal of electrolytic cell impedance simulation module 3, and the negative terminal of response voltage measurement module 5 is connected to the negative terminal of electrolytic cell impedance simulation module 3.

[0028] The DC power supply is model FTP9050-80-170. Electronic load module 2 is a high-bandwidth, energy-efficient electronic load, model Chroma63205A-150-500, with an interface for external current disturbance control. The current disturbance bandwidth is greater than 20kHz, and the electronic load's current range is set to Low, allowing for a current load of 0-50A with a given 0-10V external signal. Loop current measurement module 4 is a high-bandwidth current sensor, model Yokogawa CT60, with a measurement bandwidth of 800kHz.

[0029] The verification device has N impedance measurement channels, including one current signal acquisition channel and N response voltage signal acquisition channels. The current signal acquisition channel acquires the output value of the loop current measurement module. The electrolytic cell impedance simulation module consists of N minus one standard RC module connected in series. The N minus one response voltage signal acquisition channel acquires the terminal voltage of each of the N minus one standard RC modules, and the one response voltage signal acquisition channel acquires the total voltage of the electrolytic cell impedance simulation module.

[0030] In this embodiment, the multi-channel impedance meter to be calibrated has seven impedance measurement channels (N), including one current signal acquisition channel and seven response voltage signal acquisition channels. The current signal acquisition channel acquires the output value of the loop current measurement module 4. The electrolytic cell impedance simulation module 3 consists of six standard RC modules connected in series. The six response voltage signal acquisition channels (labeled 51~56) acquire the terminal voltages of the six standard RC modules (labeled 31~36) respectively, and one response voltage signal acquisition channel 57 acquires the total voltage of the electrolytic cell impedance simulation module 3.

[0031] The positive terminal of standard RC module one is connected to the positive terminal of the electronic load module, the negative terminal of standard RC module one is connected to the positive terminal of standard RC module two, the negative terminal of standard RC module two is connected to the positive terminal of standard RC module three, and so on. Finally, the positive terminal of standard RC module N minus one is connected to the negative terminal of standard RC module N minus two, and the negative terminal of standard RC module N minus one is connected to the positive terminal of the loop current measurement module.

[0032] The connection relationships of the six standard RC modules in this embodiment are as follows: the positive terminal of standard RC module 1 31 is connected to the positive terminal of electronic load module 2; the negative terminal of standard RC module 1 31 is connected to the positive terminal of standard RC module 2 32, and the negative terminal of standard RC module 2 32 is connected to the positive terminal of standard RC module 33; the negative terminal of standard RC module 33 is connected to the positive terminal of standard RC module 4 34, and the negative terminal of standard RC module 4 34 is connected to the positive terminal of standard RC module 5 35; the negative terminal of standard RC module 5 35 is connected to the positive terminal of standard RC module 6 36, and the negative terminal of standard RC module 6 36 is connected to the positive terminal of loop current measurement module 4.

[0033] The structure inside a standard RC module is as follows: resistor R1 and capacitor C1 are connected in parallel, denoted as R1 / / C1; resistor R2 and capacitor C2 are connected in parallel, denoted as R2 / / C2; and resistor R3 is connected in series with R1 / / C1 and R2 / / C2 in sequence.

[0034] Example 2 refer to Figures 1-3 As shown, a method for verifying the accuracy of a multi-channel impedance meter for an electrolytic cell is adopted. The method uses the accuracy verification device for the multi-channel impedance meter for an electrolytic cell in Example 1 and further includes the following verification steps: Step 1, after the multi-channel impedance meter is connected to the accuracy verification device, the power module 1 (power module FTP9050-80-170) is set to constant voltage working mode with a constant voltage of 10V, and the electronic load module 2 is set to constant current working mode controlled by an external signal.

[0035] Step 2, the frequency range of impedance measurement is: f high to f low The frequencies decreased sequentially, and a total of [number] measurements were taken. C The frequency point, the first i The frequency of each frequency point is denoted as f _ i , i =(1,2,3,… C ), initialized to i =1.

[0036] Within the frequency range of 2500Hz to 0.25Hz, from high frequency to low frequency, the number of points is taken linearly according to the natural logarithm. C =44, and the frequency is successively reduced to 0.25Hz, the first i The frequency of each frequency point is denoted as f _ i , i = (1, 2, 3, ... 44). Initialized to i =1.44. The specific frequency values ​​of the frequency points are shown in Table 1.

[0037] Table 1 shows the specific frequency values ​​for 44 frequency points.

[0038] Step 3: Provide the current signal from electronic load module 2. The current signal is a mixture of AC and DC, and the frequency of the AC signal is... f_i The amplitude of the AC signal does not exceed the amplitude of the DC signal. In this embodiment, the frequency of the AC signal is 2500Hz, the amplitude of the DC signal is 0.4V, corresponding to a DC load current of 2A, and the peak value of the AC signal is 0.2V, corresponding to an AC load current of 1A.

[0039] Step 4: The multi-channel impedance meter under test acquires signals from the loop current measurement module and response voltage measurement modules one through seven, and calculates the corresponding frequencies. f_i The AC impedance is denoted as . , k = (1, 2, 3, ... 7), indicating the position of the first... i Channel at each frequency point k impedance, Indicates the first i Channel at each frequency point k The real part of the impedance, Indicates the first i Channel at each frequency point k The imaginary part of the impedance. Where, k When = (1,2,3,…6), it represents the impedance of a single standard RC module; k When =7, it represents the total impedance of all standard RC modules.

[0040] Step 5, within the frequency range to be measured, i = i +1. Repeat steps 3 and 4 until... i = C , get all C Under each frequency point N The AC impedance value of each channel. In this embodiment, steps 3 and 4 are repeated until… i =44, thus obtaining the AC impedance values ​​of the seven channels at all 44 frequency points.

[0041] Step 6, at the same frequency f_i Below, the impedance vectors of each individual standard RC module are added together in the complex plane to obtain a composite impedance vector; the real part of this composite vector is... The imaginary part is .

[0042] At the 20th frequency point ( f Taking _20=100Hz as an example, the comparison between the synthesized impedance vector and the total impedance vector in the complex plane is shown in the appendix. Figure 4 As shown. The real part of the superimposed impedance. The imaginary part of the impedance is 1.50281. -0.74336j; the real part of the measured total impedance. The imaginary part is 1.50447. The value is -0.74451j. At this point, the relative error of the real part is... = 0.11034%, the relative error of the imaginary part is = 0.15446%.

[0043] Step 7: Define the evaluation index channel superposition relative error CIRE The relative error of the real part is denoted as . CIRE real The relative error of the imaginary part is denoted as CIRE imag This is used to measure the relative error between the combined impedance vector after multi-channel superposition and the total impedance vector. The relative errors of the real and imaginary parts are calculated as follows: (1); (2); in, Indicates taking the absolute value; Step 8: Calculate the real part of the measured impedance of each module. virtual part With the real part of the total impedance virtual part Substitute into formulas (1) and (2) to perform verification and judgment.

[0044] In step 8, it is stipulated that if CIRE real , CIRE imag If the values ​​are all less than 1%, it indicates that the simultaneous measurement of multiple channels has good consistency and passes the verification; otherwise, the verification fails and each channel needs to be recalibrated.

[0045] By iterating through all frequency points, Nyquist plots were generated for the superimposed impedance and the total system impedance. The degree of overlap between the curves can be used to preliminarily assess the consistency between the module impedance superposition and the overall response, as shown in the attached figure. Figure 5 As shown. Substituting the impedance data of each module measured at 44 frequency points and the overall impedance data into formulas (1) and (2), the results are calculated. CIRE real = 0.16254%, CIRE imag =0.53138%, all less than the specified 1%, which shows that the simultaneous measurement of multiple channels has good consistency and passes the verification.

[0046] The inventiveness of this application is: (1) structural innovation, power stage simulation and modular design.

[0047] Power stage simulation circuit structure: Adopting the same topology as the actual high-power electrolytic cell measurement circuit (power supply → electronic load → impedance simulation module → current measurement module → power supply closed loop), power stage impedance simulation is realized, overcoming the problem of disconnect between traditional signal stage simulation and actual application.

[0048] Modular impedance simulation unit: The electrolytic cell impedance simulation module consists of multiple standard RC modules connected in series. Each module adopts a second-order RC circuit structure (R1 / / C1 + R2 / / C2 + R3), which can simulate the impedance characteristics of the electrolytic cell over a wide frequency range.

[0049] (2) Multi-channel parallel verification mechanism.

[0050] Multi-channel synchronous measurement and cross-verification: Data is collected synchronously through one current channel and multiple voltage channels (N in total), enabling parallel measurement of multiple impedance modules and avoiding the cumbersome process of traditional channel-by-channel verification.

[0051] Impedance superposition consistency verification: This method proposes to superimpose the impedance vectors of each module on the complex plane and compare them with the total impedance vector. The consistency of the system is evaluated by channel superposition relative error (CIRE), which enables batch, rapid and automated accuracy verification.

[0052] (3) Evaluation methods and practical innovation.

[0053] Channel overlay relative error (CIRE): Two key error metrics are defined: CIREreal (real part relative error) and CIREimag (imaginary part relative error), used to quantify the consistency of multi-channel measurements. This metric is frequency-independent and channel-independent, making it suitable for systems of different sizes.

[0054] Verification threshold setting: Setting CIRE < 1% as the standard for passing verification provides a clear and operable judgment basis.

[0055] Easy to integrate and operate: The device has a compact structure and simple connection, and can be easily integrated into existing testing equipment. It is suitable for the periodic accuracy maintenance of multi-channel systems such as PEM electrolyzers.

[0056] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0057] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A device for verifying the accuracy of a multi-channel impedance meter for an electrolytic cell, comprising a power supply module (1), characterized in that: It also includes an electronic load module (2), an electrolytic cell impedance simulation module (3), a loop current measurement module (4), and a response voltage measurement module (5); The positive terminal of the power supply module (1) is connected to the positive terminal of the electronic load module (2), the negative terminal of the electronic load module (2) is connected to the positive terminal of the electrolytic cell impedance simulation module (3), the negative terminal of the electrolytic cell impedance simulation module (3) is connected to the positive terminal of the loop current measurement module (4), the negative terminal of the loop current measurement module (4) is connected to the negative terminal of the power supply module (1), the positive terminal of the response voltage measurement module (5) is connected to the positive terminal of the electrolytic cell impedance simulation module (3), and the negative terminal of the response voltage measurement module (5) is connected to the negative terminal of the electrolytic cell impedance simulation module (3).

2. The accuracy verification device for a multi-channel impedance meter for an electrolytic cell according to claim 1, characterized in that: The electronic load module (2) is a high-bandwidth energy-consuming electronic load with an interface for external current disturbance control, and the current disturbance bandwidth is not less than 10kHz.

3. The accuracy verification device for a multi-channel impedance meter for an electrolytic cell according to claim 1 or 2, characterized in that: The loop current measurement module (4) is a high-bandwidth current sensor with a measurement bandwidth of not less than 100kHz.

4. The accuracy verification device for a multi-channel impedance measuring instrument for an electrolytic cell according to claim 1, characterized in that: The verification device has N impedance measurement channels, including one current signal acquisition channel and N response voltage signal acquisition channels.

5. The accuracy verification device for a multi-channel impedance meter for an electrolytic cell according to claim 4, characterized in that: The current signal acquisition channel acquires the output value of the circuit current measurement module; the electrolytic cell impedance simulation module is composed of N minus one standard RC module connected in series, N minus one response voltage signal acquisition channel acquires the terminal voltage of N minus one standard RC module respectively, and one response voltage signal acquisition channel acquires the total voltage of the electrolytic cell impedance simulation module.

6. The accuracy verification device for a multi-channel impedance meter for an electrolytic cell according to claim 5, characterized in that: The positive terminal of standard RC module one is connected to the positive terminal of the electronic load module, the negative terminal of standard RC module one is connected to the positive terminal of standard RC module two, the negative terminal of standard RC module two is connected to the positive terminal of standard RC module three, and so on. Finally, the positive terminal of standard RC module N minus one is connected to the negative terminal of standard RC module N minus two, and the negative terminal of standard RC module N minus one is connected to the positive terminal of the loop current measurement module.

7. The accuracy verification device for a multi-channel impedance meter for an electrolytic cell according to claim 5 or 6, characterized in that: The structure inside a standard RC module is as follows: resistor R1 and capacitor C1 are connected in parallel, denoted as R1 / / C1; resistor R2 and capacitor C2 are connected in parallel, denoted as R2 / / C2; and resistor R3 is connected in series with R1 / / C1 and R2 / / C2 in sequence.

8. A method for verifying the accuracy of a multi-channel impedance measuring instrument for an electrolytic cell, characterized in that, The accuracy verification device for the multi-channel impedance measuring instrument for electrolytic cells according to any one of claims 1 to 7 further includes the following verification steps: Step 1: After the multi-channel impedance meter is connected to the accuracy verification device, set the power supply module (1) to constant voltage working mode and the electronic load module (2) to constant current working mode controlled by external signal. Step 2, the frequency range of impedance measurement is: f high to f low The frequencies decreased sequentially, and a total of [number] measurements were taken. C The frequency point, the first i The frequency of each frequency point is denoted as f _ i , i =(1,2,3,… C ), initialized to i =1; Step 3, provide the current signal of the electronic load module (2). The current signal is a mixture of AC and DC, and the frequency of the AC signal is... f_i The amplitude of the AC signal shall not exceed the amplitude of the DC signal; Step 4, the multi-channel impedance meter under test acquires the current measurement module (4) and the response voltage measurement module (5) of the acquisition loop. N Calculate the corresponding frequency for each signal. f_i The AC impedance is denoted as . , k =(1,2,3,… N ), indicating the first i Channel at each frequency point k impedance, Indicates the first i Channel at each frequency point k The real part of the impedance, Indicates the first i Channel at each frequency point k The imaginary part of the impedance; where, k =(1,2,3,… N- When 1), it represents the impedance of a single standard RC module. k = N When, it represents the total impedance of all standard RC modules; Step 5, within the frequency range to be measured, i = i +1, repeat steps 3 and 4 until... i = C , get all C Under each frequency point N The AC impedance value of each channel; Step 6, at the same frequency f_i Below, the impedance vectors of each individual standard RC module are added together in the complex plane to obtain a composite impedance vector; the real part of this composite vector is... The imaginary part is ; Step 7: Define the evaluation index channel superposition relative error CIRE The relative error of the real part is denoted as . CIRE real The relative error of the imaginary part is denoted as CIRE imag This is used to measure the relative error between the combined impedance vector after multi-channel superposition and the total impedance vector. The relative errors of the real and imaginary parts are calculated as follows: （1）； （2）； in, Indicates taking the absolute value; Step 8: Calculate the real part of the measured impedance of each module. virtual part With the real part of the total impedance virtual part Substitute into formulas (1) and (2) to perform verification and judgment.

9. The method for verifying the accuracy of the multi-channel impedance measuring instrument for electrolytic cells according to claim 8, characterized in that: In step 8, it is stipulated that if CIRE real , CIRE imag If the values ​​are all less than 1%, it indicates that the simultaneous measurement of multiple channels has good consistency and passes the verification; otherwise, the verification fails and each channel needs to be recalibrated.

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