A method for diagnosing failure of AEM water electrolysis membrane electrodes

Abstract

The present invention discloses a method for diagnosing failure of an AEM water electrolysis membrane electrode. The method comprises: inputting carrier waves of varying AC amplitudes during normal operation of the AEM water electrolysis membrane electrode, performing carrier wave analysis to determine the AC amplitude, and obtaining standard spectra of electrochemical AC impedance and total harmonic distortion (THD) under normal conditions; monitoring the operation of the AEM water electrolysis membrane electrode, and upon any performance change, entering a diagnostic mode, inputting a carrier wave, performing both an electrochemical AC impedance test and a total harmonic distortion test, and Fourier transforming the output electrochemical AC impedance signal to obtain an electrochemical AC impedance spectrum; processing the output harmonic signal to obtain a total harmonic distortion spectrum; and identifying the type of AEM water electrolysis membrane electrode failure based on the total harmonic distortion spectrum, combined with the electrochemical AC impedance spectrum, and comparing it with the standard spectrum obtained in step 1. The present invention can effectively diagnose failure modes of AEM water electrolysis membrane electrodes caused by temperature changes, electrolyte metering changes, and changes in anode and cathode pressure.

Description

Technical Field

[0001] The invention belongs to the field of electrochemical system diagnosis, in particular to an AEM water electrolysis membrane electrode failure diagnosis method. Background Art

[0002] AEM water electrolysis technology, like other mainstream water electrolysis technologies, may also fail during long-term operation. The reasons for its failure are diverse. Therefore, the application of AEM water electrolysis hydrogen production system urgently requires failure diagnosis for the hydrogen production system.

[0003] Currently, failure diagnosis for electrochemical systems is primarily focused on the relatively early development of fuel cells and PEM water electrolysis. Industrial production equipment is equipped with sensors for various parameters, but changes in sensor readings alone cannot identify specific failure modes. Consequently, the use of linear diagnostic techniques such as electrochemical impedance spectroscopy (EIS) combined with the development of various models has rapidly developed.

[0004] Chinese patent CN110676488A discloses an online proton exchange membrane fuel cell fault diagnosis method based on low-frequency impedance and electrochemical impedance spectroscopy. The measured low-frequency impedance is compared online with the low-frequency impedance fault threshold, and a fuzzy logic-based fault diagnosis algorithm is used to classify and diagnose the electrochemical impedance spectrum. This method can effectively distinguish between membrane dryness, water flooding, and air deficiency. However, this method is not necessarily accurate for AEM water electrolysis.

[0005] Chinese patent CN117457949A discloses a fuel cell water fault diagnosis method and system based on electrochemical impedance spectroscopy, which belongs to the field of fuel cell fault diagnosis. By measuring the electrochemical impedance spectroscopy curves of the fuel cell under different water content states, the curve feature points and local change characteristics with high correlation with water content are extracted, and the relationship between the curve characteristics and the water fault state of the fuel cell stack is established through methods such as fuzzy C-means clustering. At the same time, corresponding classification strategies are formulated based on the sensitivity differences of the curve characteristics to the dry and wet states. It can realize the detection and classification of water status through local EIS curve characteristics, but its applicability is insufficient and it only targets one type of fault.

[0006] Chinese patent CN109726452A discloses an online PEM fuel cell fault diagnosis method based on impedance spectroscopy. This method first establishes an electrochemical equivalent circuit model for the PEM fuel cell, measures the PEM fuel cell's electrochemical impedance spectrum, and uses the EIS to fit the parameters in the electrochemical equivalent circuit model. Then, some of these parameters are selected as classification features, and a fault diagnosis algorithm based on a binary tree support vector machine is used to classify the PEM fuel cell. This method can diagnose common internal PEM fuel cell faults, such as membrane drying, flooding, and air starvation.

[0007] Chinese patent CN118311346A discloses a multi-fault diagnosis method for proton exchange membrane (PEM) electrolyzers based on cell voltage variation characteristics. First, based on the existing interleaved voltage measurement topology, this diagnostic method combines a weighted corrected variance algorithm to effectively detect and distinguish between cell cell faults and voltage sensor faults. Second, by leveraging the correlation between multiple cell voltages and employing an improved correlation coefficient algorithm, this method can diagnose faults such as short circuits and water shortages.

[0008] In summary, whether the EIS and modeling analysis methods are effective for AEM water electrolysis still needs to be verified, so a diagnostic method applied to AEM water electrolysis is needed.

[0009] At present, the main reasons for the failure of AEM membrane electrode during operation are:

[0010] 1. Temperature changes: Temperature changes have a significant impact on the performance of both the catalyst and the membrane. When the temperature is too low, performance is insufficient, while when the temperature is too high, the durability of the membrane is affected. During actual production operation, the electrolyzer may have localized over-temperature or under-temperature problems, which the temperature sensor cannot accurately identify.

[0011] 2. Electrolyte metering changes (membrane drying): During electrolytic cell operation, electrolyte metering (intake volume) significantly impacts the cell's normal operation and performance. While excessively high electrolyte inflow rates will not cause the cell's diaphragm to dry out and fail, they will waste raw materials, increase overall energy consumption, and reduce performance, thereby increasing production costs. Excessively low electrolyte inflow rates can lead to insufficient electrolyte at a given current density, causing the diaphragm to dry out. Prolonged operation in this situation can damage the diaphragm, potentially halting production.

[0012] 3. Pressure fluctuation: When the cathode or anode loses pressure locally during the operation of the electrolyzer, not only will the operating performance change, but the mechanical pressure of the components will also increase, which will affect the life of the components. In severe cases, local diaphragm rupture will directly cause the device to stop. Summary of the Invention

[0013] The present invention proposes a failure diagnosis method for AEM water electrolysis membrane electrodes. By performing electrochemical AC impedance and total harmonic distortion (THD) tests on AEM water electrolysis membrane electrodes in failure mode, the method can effectively identify the electrochemical AC impedance change trend, total harmonic distortion change pattern, and total harmonic distortion characteristic frequency range under different failure modes within the 100 kHz-100 MHz frequency domain range, thereby effectively diagnosing several common failure modes of AEM water electrolysis membrane electrodes, including temperature changes, electrolyte metering changes, and anode and cathode pressure changes.

[0014] To this end, the present invention adopts the following technical solution: a method for diagnosing failure of an AEM water electrolysis membrane electrode, comprising:

[0015] Step 1: Input carrier waves of different AC amplitudes during normal operation of the AEM water electrolysis membrane electrode, perform carrier analysis, determine the AC amplitude, and obtain standard spectra of electrochemical AC impedance and total harmonic distortion under normal conditions;

[0016] Step 2: Monitor the operation of the AEM water electrolysis membrane electrodes. If any performance changes occur, enter the diagnostic mode, input the carrier, and perform an electrochemical impedance spectroscopy (EIS) test and a total harmonic distortion (THD) test simultaneously.

[0017] Step 3: Perform Fourier transform processing on the output electrochemical AC impedance signal to obtain an electrochemical AC impedance spectrum, and process the output harmonic signal to obtain a total harmonic distortion spectrum;

[0018] Step 4: Based on the total harmonic distortion spectrum, combined with the electrochemical impedance spectrum, and compared with the standard spectrum obtained in step 1, the failure type of the AEM water electrolysis membrane electrode is identified.

[0019] Compared with existing linear diagnostic technology, total harmonic distortion diagnostic technology (THDA) can capture nonlinear changes at the initial stage of a fault, locate the characteristic bands of specific faults, and achieve fast, accurate, and targeted diagnostic analysis of electrolyzer equipment, greatly improving equipment safety. In addition, THD testing can be performed simultaneously with EIS testing. Combining EIS and THD analysis can effectively identify different fault modes during AEM water electrolysis operation, making it easier for on-site maintenance personnel to carry out inspections and repairs, thereby ensuring the safety of AEM water electrolysis equipment.

[0020] Furthermore, in step 1, the AC current amplitude is determined to be at least 25% of the DC current amplitude. A larger AC current amplitude is used to reduce the impact of system noise and amplify the THD value.

[0021] Furthermore, in step 2, whether a performance change occurs is determined mainly by comparing the difference between the current density obtained by testing at the same potential and the current density during normal operation.

[0022] Furthermore, in step 1 and step 2, the input carrier is a sinusoidal carrier.

[0023] Furthermore, in step 2, the two tests performed simultaneously after entering the diagnostic mode are performed in the constant current mode.

[0024] Furthermore, in step 2, the frequency domain range of the electrochemical impedance spectroscopy test and the total harmonic distortion test is 100kHz-100mHz, from high frequency to low frequency. The wide frequency range of 100kHz-100mHz is selected to better distinguish the characteristic THD value migration range of different failure modes.

[0025] Furthermore, in step 3, the method for processing the output harmonic signal is as follows: the harmonic signal is the absolute response (Yn) of the 2nd to 10th harmonics normalized to the fundamental frequency, and the processing adopts the calculation method of the algebraic square sum square root of the 2nd to 10th harmonics to obtain the THD value at each frequency, that is, .

[0026] Furthermore, in step 4, the method for identifying the failure type of the AEM water electrolysis membrane electrode is as follows: when the anode pressure loss occurs, the performance decreases, the ohmic impedance increases, and the total harmonic distortion value increases in the frequency range of 100Hz-100mHz; when the cathode pressure loss occurs, the performance decreases, the ohmic impedance increases, and the total harmonic distortion value decreases in the frequency range of 100Hz-100mHz; when the membrane electrode electrolyte metering decreases, that is, the liquid inlet rate decreases, the ohmic impedance decreases, and the total harmonic distortion value increases in the frequency range of 631Hz-100mHz as the liquid inlet rate decreases; when the membrane electrode temperature suddenly rises, the ohmic impedance decreases, and the total harmonic distortion value increases in the frequency range of 2510Hz-100mHz.

[0027] Compared with the prior art, the technical effect of the present invention is as follows: by performing electrochemical AC impedance and total harmonic distortion tests on AEM water electrolysis membrane electrodes in failure mode, the present invention effectively identifies the electrochemical AC impedance change trend, total harmonic distortion change law and total harmonic distortion characteristic frequency range under different failure modes in the 100KHz-100mHz frequency domain range, thereby effectively diagnosing common failure modes of AEM water electrolysis membrane electrodes such as temperature changes, electrolyte metering changes and anode and cathode pressure changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a flow chart of a method for diagnosing failure of an AEM water electrolysis membrane electrode according to the present invention;

[0030] Figure 21 is an LSV diagram of an AEM water electrolysis anode at different pressures according to a specific embodiment of the present invention;

[0031] Figure 3 1 is an EIS graph of an AEM water electrolysis anode at different pressures in a specific embodiment of the present invention;

[0032] Figure 4 1 is a THD diagram of an AEM water electrolysis anode at different pressures according to a specific embodiment of the present invention;

[0033] Figure 5 1 is an LSV diagram of the AEM water electrolysis cathode at different pressures in a specific embodiment of the present invention;

[0034] Figure 6 1 is an EIS graph of the AEM water electrolysis cathode at different pressures in a specific embodiment of the present invention;

[0035] Figure 7 1 is a THD diagram of the AEM water electrolysis cathode at different pressures in a specific embodiment of the present invention;

[0036] Figure 8 2. EIS diagram of the AEM water electrolysis membrane electrode under 500 mA / cm² DC and different AC amplitude conditions in a specific embodiment of the present invention;

[0037] Figure 9 This is a THD graph of the AEM water electrolysis membrane electrode under 500 mA / cm² DC and different AC amplitude conditions in a specific embodiment of the present invention;

[0038] Figure 10 1 is an LSV diagram of an AEM water electrolysis membrane electrode under different cathode pressure conditions in a specific embodiment of the present invention;

[0039] Figure 11 1 is an EIS diagram of an AEM water electrolysis membrane electrode under different cathode pressure conditions in a specific embodiment of the present invention;

[0040] Figure 12 2. This is a THD diagram of the AEM water electrolysis membrane electrode under different cathode pressure conditions in a specific embodiment of the present invention;

[0041] Figure 13 1. LSV diagram of the AEM water electrolysis membrane electrode under different electrolyte metering (liquid feeding rate) conditions in a specific embodiment of the present invention;

[0042] Figure 14 1 is an EIS graph of an AEM water electrolysis membrane electrode under different electrolyte metering (liquid feeding rate) conditions in a specific embodiment of the present invention;

[0043] Figure 152. The THD diagram of the AEM water electrolysis membrane electrode under different electrolyte metering (liquid feeding rate) conditions in a specific embodiment of the present invention;

[0044] Figure 16 1. LSV diagram of the AEM water electrolysis membrane electrode under different temperature conditions in a specific embodiment of the present invention;

[0045] Figure 17 1 is an EIS diagram of the AEM water electrolysis membrane electrode under different temperature conditions in a specific embodiment of the present invention;

[0046] Figure 18 2. This is a THD diagram of the AEM water electrolysis membrane electrode under different temperature conditions in a specific embodiment of the present invention;

[0047] In the figure, Z' and Z'' represent the real part (resistance component) and imaginary part (capacitance or inductance component) of impedance, respectively; AC represents the alternating current amplitude. DETAILED DESCRIPTION

[0048] The present invention is described in detail below with reference to the accompanying drawings and specific implementation methods. The present invention includes but is not limited to the following embodiments.

[0049] The electrolyte used in this embodiment is 1 mol / L KOH solution, and the electrolyte enters the anode.

[0050] This embodiment provides a method for diagnosing failure of an AEM water electrolysis membrane electrode. Figure 1 As shown, the steps are as follows:

[0051] Step 1: Input carrier waves of different AC amplitudes during normal operation of the AEM water electrolysis membrane electrode, perform carrier analysis, determine the AC amplitude, and obtain standard spectra of electrochemical AC impedance and total harmonic distortion under normal conditions;

[0052] Step 2: Monitor the operation of the AEM water electrolysis membrane electrodes. If any performance changes occur, enter the diagnostic mode, input the carrier, and perform an electrochemical impedance spectroscopy (EIS) test and a total harmonic distortion (THD) test simultaneously.

[0053] Step 3: Perform Fourier transform processing on the output electrochemical AC impedance signal to obtain an electrochemical AC impedance spectrum, and process the output harmonic signal to obtain a total harmonic distortion spectrum;

[0054] Step 4: Based on the total harmonic distortion spectrum, combined with the electrochemical impedance spectrum, and compared with the standard spectrum obtained in step 1, the failure type of the AEM water electrolysis membrane electrode is identified.

[0055] Specifically, in step 1, the determined AC current amplitude is 25% of the DC current amplitude.

[0056] Specifically, in step 2, determining whether a performance change occurs is mainly performed by comparing the difference between the current density obtained by testing at the same potential and the current density during normal operation.

[0057] Specifically, in steps one and two, the input carrier is a sinusoidal carrier; in step two, the two tests performed simultaneously after entering the diagnostic mode are performed in constant current mode; the frequency domain range of the electrochemical AC impedance test and the total harmonic distortion test is 100kHz-100mHz, from high frequency testing to low frequency.

[0058] Specifically, the data processing in step 3 is as follows: the harmonic signal is the absolute response (Yn) of the 2nd to 10th harmonics normalized to the fundamental frequency, and the processing adopts the calculation method of the algebraic square sum square root of the 2nd to 10th harmonics to obtain the THD value at each frequency, that is, .

[0059] Specifically, in step 4, the method for identifying the failure type of the AEM water electrolysis membrane electrode is as follows: when the anode pressure loss occurs, the performance decreases, the ohmic impedance increases, and the total harmonic distortion value increases in the frequency range of 100Hz-100mHz; when the cathode pressure loss occurs, the performance decreases, the ohmic impedance increases, and the total harmonic distortion value decreases in the frequency range of 100Hz-100mHz; when the membrane electrode electrolyte metering decreases, that is, the liquid inlet rate decreases, the ohmic impedance decreases, and the total harmonic distortion value increases in the frequency range of 631Hz-100mHz as the liquid inlet rate decreases; when the membrane electrode temperature suddenly increases, the ohmic impedance decreases, and the total harmonic distortion value increases in the frequency range of 2510Hz-100mHz.

[0060] The formation process of the above-mentioned AEM water electrolysis membrane electrode failure diagnosis method is described in detail below.

[0061] according to Figure 1The process begins by monitoring the performance of the AEM water electrolyzer during operation. This example uses LSV (Linear Voltammetry) to simulate performance changes during failure monitoring. When the AEM water electrolyzer is operating normally, carrier waves with different AC amplitudes are input to select the test amplitude, and standard EIS and THD spectra are obtained during normal operation. The EIS and THD spectrum experimental results are simultaneously measured using an electrochemical workstation equipped with a harmonic analysis module. Generally, THD experimental results are composed of two components, THD and noise N, namely THD+N. Therefore, the selection of AC amplitude during measurement is crucial. THD results increase by orders of magnitude with increasing AC amplitude, while the noise signal decreases with increasing amplitude. The opposite trend between noise and THD values ​​with amplitude makes it possible to define the effective frequency range of the THD spectrum through amplitude optimization. However, although THD intensity increases significantly and noise signal decreases significantly with increasing amplitude, frequency response analysis should also consider the actual electrode process and minimize the impact of disturbance signals on the electrode process during testing. Therefore, the amplitude selection principle in their experimental research is: select the minimum amplitude in which THD changes significantly in the sensitive frequency domain range of electrochemical reaction kinetics; when the performance changes, enter the diagnostic mode, that is, input the carrier, and perform the next step of electrochemical AC impedance and total harmonic distortion testing. The harmonic test results and EIS test results can be obtained simultaneously after the EIS test. The measured data is processed to obtain the EIS change law, find the THD characteristic frequency domain change range, and compare with the obtained standard spectrum to identify and diagnose the specific failure type.

[0062] In order to verify the feasibility of applying total harmonic distortion technology to AEM water electrolysis, a simulation test of the pressure loss of the anode and cathode of AEM water electrolysis was first carried out, that is, a three-electrode system was used to test the anode and cathode separately under different pressure conditions. The test process was the same as Figure 1 After each experimental condition is stabilized, the test is performed three times. The EIS and THD test settings are the same as step 2 of the present invention, and the spectra with error bars are prepared.

[0063] according to Figure 2 and Figure 5 The test results show that the performance of both the anode and cathode will decrease when the pressure drops; Figure 3 and Figure 6 It can be seen from the Nyquist plot of EIS that as the pressure decreases, the ohmic impedance of the cathode and anode increases; Figure 4 and Figure 7It can be found in the THD spectrum that in the frequency domain range of 100Hz-100mHz, the change trends of the anode and cathode THD when the pressure drops are opposite. When the pressure drops, the THD of the anode increases significantly in this frequency domain, while the THD of the cathode decreases significantly in this frequency domain. The opposite change trends of the anode and cathode THD in the same frequency domain can be used as a basis for using the total harmonic distortion technology combined with the electrochemical AC impedance technology to diagnose which specific part of the anode and cathode fails due to pressure loss, proving the feasibility of applying the total harmonic distortion technology in AEM water electrolysis.

[0064] Combined with the current density selected in the stability test of AEM water electrolysis catalyst, 500mA / cm² DC was selected as the working point of the test example. The EIS test results under different amplitude conditions are as follows: Figure 8 As shown, the THD test results are as follows Figure 9 As shown, the amplitude has little effect on the EIS results, but significantly impacts the THD spectrum. As the amplitude increases to 500mA (125mA / cm²), the THD value at mid- and low-frequency frequencies essentially eliminates the effects of noise. Therefore, an amplitude of 125mA / cm², or 25% of the DC current level, was selected. To ensure data consistency, subsequent AEM water electrolysis membrane electrode testing was conducted based on this result.

[0065] The first failure mode created is the influence of pressure fluctuations. When the membrane electrode is in operation, since the anode is on the liquid inlet side, the pressure is held on the cathode side, and hydrogen is selected as the pressure holding gas. Three tests are performed after the pressure conditions stabilize.

[0066] like Figure 10 As shown, as the pressure decreases, the performance of the membrane electrode decreases; Figure 11 As can be seen from the figure, the ohmic impedance increases with the decrease of pressure, which is consistent with the LSV result. Figure 12 It can be seen from the THD spectrum that the THD value decreases in the range of 100Hz-100mHz as the pressure decreases, which corresponds to the test results of the pressure fluctuation diagnosis of the above-mentioned single anode and cathode electrodes, proving the correctness of the single anode and cathode test results, and also indicating that the specific frequency domain range of this failure mode is 100Hz-100mHz, and the change trend is to decrease with decreasing pressure.

[0067] The second failure mode created was diaphragm dry-burning, which is the influence of electrolyte metering. The data acquisition method uses a high-voltage constant-current pump to control different electrolyte inlet flow rates to achieve different metering. The portable heating table maintains the constant temperature of the membrane electrode. After stabilization under each electrolyte flow rate condition, three tests are performed, and the test parameter settings are the same as above.

[0068] like Figure 13As shown in the figure, as the liquid inlet rate decreases from 2mL / min to 0.1mL / min, the performance of the membrane electrode improves. Although the performance is the best at the minimum liquid inlet rate, after the experiment under this condition, the membrane electrode was disassembled and it was found that the edge of the AEM had cracked and the mechanical strength had dropped significantly, making it unusable. Figure 14 It can be seen from the EIS graph that the impedance decreases as the liquid inlet rate decreases; the THD spectrum also has a characteristic frequency domain range with the change of liquid inlet rate. Figure 15 It can be seen that as the liquid inlet volume decreases, the THD increases in the range of 631Hz-100mHz. It can be found that the characteristic frequency domain range of failure caused by metering is in the range of 631Hz-100mHz, and the THD value increases when the diaphragm dry burns.

[0069] The third failure mode created is the influence of temperature change. Different temperature conditions are controlled. LSV, EIS and THD tests are performed after each temperature condition stabilizes. The test parameters are set the same as step 2 of the present invention. The three tests are performed after the temperature stabilizes.

[0070] like Figure 16 As shown in the figure, when the temperature increases, the performance of the AEM water electrolysis membrane electrode is significantly improved. Figure 17 The test results show that as the temperature increases, the ohmic impedance decreases significantly. Figure 18 It can be seen that as the temperature rises, the THD value of the membrane electrode increases significantly in the range of 2510Hz-100mHz. The characteristic frequency range of temperature-induced failure is 2510Hz-100mHz, and THD increases in this frequency range as the temperature rises.

[0071] The test results of these failure modes are summarized in Table 1. When the membrane electrode cathode loses pressure, the performance decreases, the impedance increases, and the THD value decreases in the range of 100Hz-100mHz. When the anode loses pressure, the performance decreases, the impedance increases, and the THD value increases in the range of 100Hz-100mHz. When the temperature rises and the diaphragm burns dry, that is, the electrolyte metering decreases, the performance is improved and the impedance decreases. At this time, it is impossible to distinguish them based on EIS alone. However, combined with the THD spectrum, it can be seen that these two failure modes have different characteristic frequency domain ranges. When the temperature rises, the THD value increases significantly in the range of 2510Hz-100mHz, and when the diaphragm burns dry, the THD increases in the range of 631Hz-100mHz. That is, the characteristic frequency domain range of temperature change is 2510Hz-631Hz, the characteristic frequency domain range of metering change is 631Hz-100Hz, and the characteristic frequency domain range of pressure change is 100Hz-100mHz. Therefore, by combining the EIS graph with the THD graph and finding the changing trend in the characteristic frequency domain on the THD graph, these failure modes can be effectively distinguished.

[0072] Table 1 Summary of changes in LSV, EIS, and THD of AEM water electrolysis membrane electrodes under four failure modes

[0073]

[0074] The above embodiments are merely illustrative of the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the essence of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for diagnosing failure of an AEM water electrolysis membrane electrode, characterized in that: include: Step 1: Input carrier waves of different AC amplitudes during normal operation of the AEM water electrolysis membrane electrode, perform carrier analysis, determine the AC amplitude, and obtain standard spectra of electrochemical AC impedance and total harmonic distortion under normal conditions; Step 2: Monitor the operation of the AEM water electrolysis membrane electrode. If any performance changes occur, enter the diagnostic mode, input the carrier, and perform an electrochemical AC impedance test and a total harmonic distortion test at the same time. Step 3: Perform Fourier transform processing on the output electrochemical AC impedance signal to obtain an electrochemical AC impedance spectrum, and process the output harmonic signal to obtain a total harmonic distortion spectrum; Step 4: Based on the total harmonic distortion spectrum and the electrochemical impedance spectrum, the failure type of the AEM water electrolysis membrane electrode is identified by comparing it with the standard spectrum obtained in step 1; In step 1, the AC current amplitude is determined to be at least 25% of the DC current amplitude; In step 4, the method for identifying the type of AEM water electrolysis membrane electrode failure is as follows: when the anode pressure loss occurs, the performance decreases, the ohmic impedance increases, and the total harmonic distortion value increases in the frequency range of 100Hz-100mHz; when the cathode pressure loss occurs, the performance decreases, the ohmic impedance increases, and the total harmonic distortion value decreases in the frequency range of 100Hz-100mHz; when the membrane electrode electrolyte metering decreases, that is, the liquid inlet rate decreases, the ohmic impedance decreases, and the total harmonic distortion value increases in the frequency range of 631Hz-100mHz as the liquid inlet rate decreases; when the membrane electrode temperature suddenly rises, the ohmic impedance decreases, and the total harmonic distortion value increases in the frequency range of 2510Hz-100mHz.

2. The AEM water electrolysis membrane electrode failure diagnosis method according to claim 1, characterized in that: In step 2, whether performance changes occur is mainly determined by comparing the difference between the current density obtained by testing at the same potential and the current density during normal operation.

3. The AEM water electrolysis membrane electrode failure diagnosis method according to claim 1, characterized in that: In step 1 and step 2, the input carrier is a sinusoidal carrier.

4. The AEM water electrolysis membrane electrode failure diagnosis method according to claim 1, characterized in that: In step 2, the two tests performed simultaneously after entering the diagnostic mode are performed in the constant current mode.

5. The AEM water electrolysis membrane electrode failure diagnosis method according to claim 1, characterized in that: In step 2, the frequency domain range of the electrochemical AC impedance test and the total harmonic distortion test is 100kHz-100mHz, from high frequency to low frequency.

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