A performance test system for a pem electrolyzer

Abstract

The present application relates to the technical field of PEM electrolyzer performance testing, and specifically discloses a kind of performance test system of PEM electrolyzer, comprising: maximum current density overestimation problem is identified by water flow rate sensitivity test, and dynamic mass transfer verification and actual operation scene adaptation dynamic working condition test, dynamic mass transfer limit and gas diffusion layer dynamic mass transfer critical value are clear, aging attenuation law of gas diffusion layer dynamic mass transfer critical value is quantified based on historical data, through actual operation verification, the test deviation of mismatched gas diffusion layer real-time aging is corrected, through mismatch test prediction and parameter correction, future parameter mismatch test is positioned in advance and pre-correction is carried out, the problem that existing static test does not consider gas diffusion layer dynamic mass transfer limit and aging influence, leading to maximum current density overestimation is solved, the dynamic adaptation of gas diffusion layer aging state and test parameter is realized, and the test result and actual operation deviation are reduced.

Description

Technical Field

[0001] This invention relates to the field of PEM electrolytic cell performance testing technology, and more specifically to a performance testing system for PEM electrolytic cells. Background Technology

[0002] As a high-efficiency hydrogen production device, the performance test results of PEM electrolyzers directly guide the optimization of actual operating parameters. Current performance tests for PEM electrolyzers mostly employ static stepped load testing. This testing method has two major drawbacks: First, it fails to consider the dynamic mass transfer limitations of the gas diffusion layer caused by frequent load changes during actual operation. The high water flow rate in static testing can mask the insufficient oxygen removal capacity of the gas diffusion. Second, it does not adjust the test parameters according to the aging state of the gas diffusion. During long-term operation, the gas diffusion exhibits aging phenomena such as decreased hydrophobicity, hydrophobic layer shedding, and blockage of mass transfer channels, leading to a continuous decline in its dynamic mass transfer capacity. Static testing, using fixed parameters from the new gas diffusion, results in an overestimation of the maximum current density, leading to a significant deviation between the test results and actual operating conditions.

[0003] In existing technologies, some testing schemes attempt to adjust the water flow rate or load parameters, but lack a quantitative correlation with the gas diffusion aging state, and have not established a model for the decay law of dynamic mass transfer critical value, thus failing to achieve dynamic adaptation of test parameters. At the same time, existing schemes are mostly retrospective corrections, which cannot predict the risk of parameter mismatch in advance, resulting in repeated test distortion problems, which seriously affect the operational stability and hydrogen production efficiency of PEM electrolyzers.

[0004] Therefore, the present invention provides a performance testing system for PEM electrolyzers. Summary of the Invention

[0005] The purpose of this invention is to provide a performance testing system for PEM electrolyzers to solve the aforementioned background problems.

[0006] The objective of this invention can be achieved through the following technical solution: a performance testing system for a PEM electrolyzer, comprising the following modules:

[0007] Test mismatch determination module: Performs water flow velocity sensitivity test under the current static test conditions, and determines whether there is a test mismatch by comparing and analyzing the test results;

[0008] Dynamic mass transfer verification module: If it exists, test under dynamic operating conditions to obtain the dynamic maximum current density, and compare and analyze it with the static maximum current density to determine whether the test mismatch is caused by dynamic mass transfer limitation. If so, determine the dynamic mass transfer critical value of the gas diffusion layer by the current density change amplitude gradient test.

[0009] Attenuation model construction module: Based on historical operating data of PEM electrolyzers, a dynamic mass transfer critical value attenuation model is constructed;

[0010] Test result correction module: Run the PEM electrolyzer to obtain the actual maximum current density, and compare and analyze it with the dynamic test maximum current density to determine whether the actual maximum current density matches the dynamic test maximum current density. If they do not match, call the dynamic mass transfer critical value decay model to correct the test maximum current density.

[0011] Prediction parameter correction module: If a match is found, the dynamic mass transfer critical value for future periodic performance tests is predicted based on the dynamic mass transfer critical value decay model, mismatch tests are located, and the test parameters for mismatch tests are corrected.

[0012] Furthermore, the method for determining whether a test mismatch exists is as follows:

[0013] Keep all static test conditions constant, including temperature, pressure, and load as a stepped constant current density, and only change the water flow rate;

[0014] Two sets of tests were set up, including a benchmark test and a low water flow rate test. The benchmark test used the original constant water flow rate to test and record the static maximum current density. The low water flow rate test reduced the water flow rate by one gradient and tested under the same load step, recording the maximum current density at the low water flow rate.

[0015] Calculate the deviation between the static maximum current density and the maximum current density at low water flow rate. If the deviation meets the requirements, then there is a test mismatch.

[0016] Furthermore, the method for determining whether the test mismatch is caused by dynamic mass transfer limitations is as follows:

[0017] Set the dynamic operating condition test parameters to be the same as the actual operating conditions of the PEM electrolyzer, and conduct the test under the dynamic operating condition parameters to obtain the dynamic maximum current density.

[0018] The static maximum current density, the maximum current density at low water flow rate, and the dynamic maximum current density of the gas diffusion layer are compared.

[0019] If the dynamic maximum current density < the low water flow rate maximum current density < the static maximum current density, and air blockage characteristics appear in the dynamic test, but no air blockage appears in the static low water flow rate group, then the test mismatch is caused by dynamic mass transfer limitation.

[0020] Among them, the characteristics of airlock include voltage changes and local temperature differences meeting the requirements.

[0021] Furthermore, the method for determining airlock characteristics during the dynamic test is as follows:

[0022] During dynamic testing, the voltage and local temperature difference within the time window after the current density completes the low-load-high-load switching are monitored. The local temperature difference area is the gas diffusion layer area covered by the flow channel on the anode side of the gas diffusion layer and the gas diffusion layer area in the flow channel gap.

[0023] Three consecutive dynamic cyclic tests were performed under the same current density abrupt change amplitude:

[0024] If the voltage and local temperature difference both meet the requirements within the time window of the three cycles, it is determined that airlock characteristics have occurred in the dynamic test.

[0025] Furthermore, the dynamic operating condition test parameters are set as follows:

[0026] Dynamic operating condition test parameters include current density change amplitude, load switching speed and time, cycle period and number of cycles, water flow rate, temperature and pressure;

[0027] The current density fluctuation amplitude is taken as the 95th percentile load fluctuation amplitude in actual operation, and the load switching time is taken as the load switching response time in actual operation.

[0028] The cycle period includes the low load duration = the actual low load stabilization time during operation, the high load duration = the actual high load stabilization time during operation, and the number of cycles is the actual daily average load cycle number during operation.

[0029] The water flow rate, temperature, and pressure were consistent with those of the static test.

[0030] Furthermore, the process for determining the dynamic mass transfer critical value is as follows:

[0031] Calculate the maximum difference in current density from low load to high load per unit time to obtain the maximum current density jump amplitude.

[0032] Starting from the 95th percentile current density mutation amplitude in actual operation, gradually increase the current density mutation amplitude. Each time it is adjusted, perform 3 cycle tests under dynamic operating conditions to observe whether air blockage is triggered.

[0033] The minimum current density change amplitude that triggers gas blockage for the first three consecutive cycles is the dynamic mass transfer critical value of the gas diffusion layer.

[0034] Furthermore, the construction process of the dynamic mass transfer critical value decay model includes:

[0035] Obtain historical operating data of PEM electrolyzers, including: cumulative operating time of PEM electrolyzers, distribution of actual load fluctuation amplitude, constant water flow rate, and temperature and pressure fluctuation data;

[0036] The dynamic mass transfer critical value of the gas diffusion layer is calculated, and a dynamic mass transfer critical value decay model is constructed with the cumulative running time as the independent variable and the historical dynamic mass transfer critical value as the dependent variable. ;

[0037] in, α is the initial dynamic mass transfer critical value of the new gas diffusion layer, t is the cumulative running time, and α is the rate of decrease of the dynamic mass transfer critical value per hour of running obtained by fitting.

[0038] (130-θ) is the decrease in the current contact angle relative to the optimal hydrophobicity, and β is the percentage decrease in the dynamic mass transfer critical value caused by each 1° decrease in the fitted contact angle.

[0039] (85-P) represents the decrease in PTFE retention relative to the optimal hydrophobic layer, and γ is the percentage decrease in the critical mass transfer value caused by each 1% decrease in PTFE retention obtained from the fitting.

[0040] Furthermore, the method for determining whether the actual maximum current density matches the dynamic test maximum current density is as follows:

[0041] Run the electrolytic cell continuously for one cycle, record the stable maximum current density in each small cycle, and take the average value as the actual maximum current density.

[0042] Calculate the deviation rate between the dynamic maximum current density obtained under dynamic operating conditions and the actual maximum current density. If the deviation rate meets the requirements, the actual maximum current density matches the dynamic test maximum current density; otherwise, they do not match.

[0043] Furthermore, the process of correcting the maximum current density of the test is as follows:

[0044] If they do not match, call the dynamic mass transfer critical value decay model to calculate the true dynamic mass transfer critical value under the current cumulative runtime.

[0045] Corrected maximum current density for dynamic testing: Corrected maximum current density for dynamic testing = Maximum current density for dynamic testing × (True dynamic mass transfer critical value / Dynamic mass transfer critical value obtained from dynamic testing).

[0046] Furthermore, the prediction method for the dynamic mass transfer critical value of the future periodic performance test is as follows:

[0047] Based on the current performance testing cycle of the PEM electrolyzer, the cumulative runtime of the nth periodic test is t. n =n × test period;

[0048] The dynamic mass transfer critical value decay model is invoked to predict the dynamic mass transfer critical value for each periodic performance test.

[0049] Furthermore, the method for the positioning mismatch test is as follows:

[0050] For any periodic performance test, calculate the decay rate of the predicted dynamic mass transfer critical value relative to the current actual dynamic mass transfer critical value to obtain the predicted decay rate: Predicted decay rate = (Current actual dynamic mass transfer critical value - Predicted dynamic mass transfer critical value) / Current actual dynamic mass transfer critical value.

[0051] When the predicted decay rate meets the requirements, and the current test parameters do not match the predicted dynamic mass transfer critical value, the periodic performance test will be marked as a mismatch test.

[0052] Furthermore, the process of correcting the test parameters for the mismatch test is as follows:

[0053] The correction value for the magnitude of the current density change is the dynamic mass transfer critical value predicted by the decay model at the mismatch test time point, which is the limit of the oxygen removal capacity of the gas diffusion layer at that time point in the future.

[0054] Adjust the load switching time based on the predicted contact angle from the mismatch test. ,in, The static contact angle of the gas diffusion layer at the mismatch test time point is predicted by the attenuation model.

[0055] Furthermore, the process of correcting the test parameters for the mismatch test is as follows:

[0056] Adjust the low-load duration based on the gas permeability predicted by the model for this test: , where k pred This represents the gas permeability of the gas diffusion layer at the mismatch test time point predicted by the attenuation model.

[0057] The beneficial effects of this invention are as follows:

[0058] By rapidly screening for overestimation of maximum current density in gas diffusion layer mass transfer mismatch tests caused by high water flow rate masking gas diffusion layer mass transfer limitations, this method avoids invalid analysis of tests without overestimation issues, provides a basis for subsequent accurate correction, and solves the problem that existing tests cannot identify overestimation in advance, leading to inaccurate optimization of operating parameters.

[0059] By verifying and determining the critical value through dynamic mass transfer, we can accurately distinguish whether the overestimation is caused by static or dynamic mass transfer limitations. At the same time, we can quantitatively obtain the dynamic mass transfer critical value, a core indicator that reflects the true mass transfer capability of the gas diffusion layer. This solves the problem that existing technologies cannot distinguish the root cause of overestimation and correct it without specificity, and provides a clear basis for subsequent quantitative correction.

[0060] By constructing a dynamic mass transfer critical value decay model, the physical characteristics of gas diffusion layer aging are quantitatively linked to the decay of dynamic mass transfer capacity, which solves the problem that it is impossible to grasp the mass transfer decay trend of gas diffusion layer by relying on single test data, and provides mathematical support for subsequent real-time correction and pre-emptive prevention.

[0061] The test result correction module aligns the dynamic test results with the actual mass transfer capacity during operation, corrects the deviation caused by the real-time aging of the gas diffusion layer not being adapted to the test parameters, and solves the problem of distorted test results that cannot provide a reliable basis for current operation.

[0062] By using imbalance test location and parameter pre-correction, the system can identify imbalance tests that may lead to parameter mismatch in future periodic tests based on the attenuation model. It can also pre-adapt the test parameters to the predicted aging state of the gas diffusion layer, thereby avoiding future test overestimation. This solves the problems of repeated test distortion and poor long-term test stability, and achieves an upgrade from post-correction of deviations to pre-prevention of mismatch. Attached Figure Description

[0063] The invention will now be further described with reference to the accompanying drawings.

[0064] Figure 1 This is a functional block diagram of a performance testing system for a PEM electrolyzer according to the present invention;

[0065] Figure 2 This is a flowchart in the present invention for determining whether a test mismatch is caused by dynamic mass transfer limitations. Detailed Implementation

[0066] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0067] Example: Please refer to Figure 1 As shown, the performance testing system for a PEM electrolyzer of this invention addresses the test mismatch caused by dynamic mass transfer limitations and aging effects of the gas diffusion layer. It identifies the overestimation of maximum current density through water flow velocity sensitivity testing, and clarifies the dynamic mass transfer limitations and critical values ​​of the gas diffusion layer through dynamic mass transfer verification and dynamic operating condition testing adapted to actual operating scenarios. Based on historical data, it quantifies the aging decay law of the gas diffusion layer's dynamic mass transfer critical values. Through actual operation verification, it corrects the test deviation of mismatched gas diffusion layer real-time aging. By predicting mismatch tests and correcting parameters, it pre-positions and corrects future parameter mismatch tests, solving the problem of overestimation of maximum current density caused by existing static tests that do not consider the dynamic mass transfer limitations and aging effects of the gas diffusion layer. It achieves dynamic adaptation between the aging state of the gas diffusion layer and test parameters, reducing the deviation between test results and actual operation. Specifically, it includes the following modules:

[0068] Test mismatch determination module: Performs water flow velocity sensitivity test under the current static test conditions, and determines whether there is a test mismatch by comparing and analyzing the test results;

[0069] The process of determining whether a test mismatch exists includes:

[0070] By changing the water flow rate in the static test and observing the change in the maximum current density, we can determine whether there is an overestimation of the maximum current density. Specifically:

[0071] Keep all static test conditions constant, including temperature, pressure, and load as a stepped constant current density, and only change the water flow rate;

[0072] Two sets of tests were set up, including a benchmark test and a low water flow rate test. The benchmark test used the original constant water flow rate and used an electrical sensor to collect the static maximum current density. The low water flow rate test reduced the water flow rate by 20% and tested under the same load step, using an electrical sensor to collect the maximum current density at the low water flow rate.

[0073] Calculate the deviation between the static maximum current density and the low water flow rate maximum current density, and compare it with the preset deviation. If the deviation is greater than or equal to the preset deviation, there is a test mismatch.

[0074] Understandably, the preset deviation is the threshold for judging whether the maximum current density of the gas diffusion layer is overestimated under static testing. If the deviation is greater than or equal to the preset deviation, it means that the high water flow rate of the original constant water flow rate is the key to maintaining the original maximum current density. Once the oxygen removal capacity weakens (the water flow rate decreases), the mass transfer limitation of the gas diffusion layer will be exposed. Under actual dynamic conditions, when the load changes suddenly and oxygen increases sharply, the constant water flow rate cannot improve the oxygen removal capacity, and the actual maximum current density will be lower than the maximum current density, which means there is a test mismatch.

[0075] It should be noted that the purpose of the test mismatch determination is to quickly identify the problem of overestimation of maximum current density caused by high water flow rate masking the mass transfer limitation of gas diffusion layer in static test, so as to provide a basis for subsequent root cause investigation and correction, and avoid invalid subsequent analysis of tests without overestimation problems.

[0076] Dynamic mass transfer verification module: If it exists, test under dynamic operating conditions to obtain the dynamic maximum current density, and compare and analyze it with the static maximum current density to determine whether the test mismatch is caused by dynamic mass transfer limitation. If so, determine the dynamic mass transfer critical value of the gas diffusion layer by the current density change amplitude gradient test.

[0077] Please see Figure 2 As shown, the process for determining whether the test mismatch is caused by dynamic mass transfer limitations includes:

[0078] Set dynamic operating condition test parameters identical to those used in the actual operation of the PEM electrolyzer. These parameters include current density fluctuation amplitude, load switching speed and time, cycle period and number of cycles, water flow rate, temperature, and pressure. The specific setup process is as follows:

[0079] The current density fluctuation range is taken as the 95th percentile load fluctuation range in actual operation (that is, the range that 95% of the load fluctuations in actual operation will not exceed).

[0080] The load switching time is taken as the actual load switching response time during operation;

[0081] The cycle period includes the low load duration = the actual low load stabilization time during operation, the high load duration = the actual high load stabilization time during operation, and the number of cycles is the actual daily average load cycle number during operation.

[0082] The water flow rate, temperature, and pressure were consistent with the static test.

[0083] The test was conducted under dynamic operating parameters to obtain the dynamic maximum current density, which reflects the true mass transfer capability of the gas diffusion layer under actual dynamic load.

[0084] Compare the static maximum current density, the low water flow rate maximum current density, and the dynamic maximum current density of the gas diffusion layer. If the dynamic maximum current density < the low water flow rate maximum current density < the static maximum current density, and air blockage characteristics appear in the dynamic test, but no air blockage appears in the static low water flow rate group, then the test mismatch is caused by dynamic mass transfer limitation.

[0085] The process of identifying airlock characteristics during dynamic testing is as follows:

[0086] During dynamic testing, the voltage and local temperature difference within the time window after the current density completes the low-load-high-load switching are monitored. The local temperature difference area is the gas diffusion layer area covered by the flow channel on the anode side of the gas diffusion layer and the gas diffusion layer area in the flow channel gap.

[0087] Three consecutive dynamic cyclic tests were performed under the same current density abrupt change amplitude:

[0088] If the voltage and local temperature difference both meet the requirements within the time window of the three cycles, it is determined that airlock characteristics have occurred in the dynamic test.

[0089] It is understandable that the logic for judging whether the mismatch is caused by dynamic mass transfer limitation is as follows: under static conditions, low water flow rate can still maintain a certain mass transfer, but under dynamic conditions, sudden load changes cause a sudden increase in oxygen, the dynamic mass transfer capacity of the gas diffusion layer is insufficient, triggering gas blockage, and the maximum current density in actual operation is limited.

[0090] The process for determining the dynamic mass transfer critical value includes:

[0091] The dynamic mass transfer critical value of a gas diffusion layer refers to the maximum change in reaction rate that can be matched under dynamic operating conditions without gas blockage / water blockage. The quantitative index is:

[0092] The maximum current density jump amplitude is the maximum difference in current density from low load to high load per unit time. If this value is exceeded, the oxygen removal rate of the gas diffusion layer cannot match the oxygen generation rate, causing gas blockage.

[0093] The corresponding maximum reaction rate change is calculated from the maximum current density abrupt change (reaction rate is proportional to current density), which directly reflects the tolerance limit of the gas diffusion layer to changes in reaction rate.

[0094] It is understandable that the physical meaning of the dynamic mass transfer critical value of the gas diffusion layer is: the balance threshold between the mass transfer capacity of the gas diffusion layer and the change in reaction rate. If it is exceeded, there is a mass transfer mismatch. It is the core quantitative indicator for judging the dynamic adaptability of the gas diffusion layer.

[0095] The logic for determining the dynamic mass transfer critical value is as follows: under controlled variables, gradually increase the amplitude of the current density mutation, and capture the minimum current density mutation amplitude that causes gas blockage, which is the dynamic mass transfer critical value. Specifically:

[0096] Starting from the 95th percentile current density mutation amplitude in actual operation, gradually increase the current density mutation amplitude (increase by 0.1A / cm² each time); after each adjustment, perform 3 cycle tests under dynamic operating conditions to observe whether air lock is triggered;

[0097] The minimum current density change amplitude that triggers gas blockage for the first three consecutive cycles using an electrical sensor is the dynamic mass transfer critical value of the gas diffusion layer, which is the maximum current density change amplitude that can be matched when the gas diffusion layer does not experience gas blockage under dynamic operating conditions.

[0098] It should be noted that the role of dynamic mass transfer verification and critical value determination is to clarify whether the core cause of the overestimation problem is the limitation of dynamic mass transfer in the gas diffusion layer, and at the same time to obtain the dynamic mass transfer critical value, which is the core parameter for quantifying the mass transfer capacity of the gas diffusion layer, so as to provide a benchmark quantitative basis for subsequent model construction and parameter correction.

[0099] Attenuation model construction module: Based on historical operating data of PEM electrolyzers, a dynamic mass transfer critical value attenuation model is constructed;

[0100] The construction process of the dynamic mass transfer critical value decay model includes:

[0101] Obtain historical operating data of PEM electrolyzers, including: cumulative operating time of PEM electrolyzers, distribution of actual load fluctuation amplitude, constant water flow rate, and temperature and pressure fluctuation data;

[0102] The dynamic mass transfer critical value of the gas diffusion layer is calculated, and a dynamic mass transfer critical value decay model is constructed with the cumulative running time as the independent variable and the historical dynamic mass transfer critical value as the dependent variable. ;

[0103] in, This is the initial dynamic mass transfer critical value of the new gas diffusion layer, corresponding to the dynamic mass transfer capacity of the gas diffusion layer in the optimal oxygen removal state.

[0104] α×t reflects the cumulative aging effect of operating time on mass transfer capacity: the alternation of dry and wet conditions, load fluctuations, and temperature and pressure fluctuations during the operation of the PEM electrolyzer will continuously wear down the hydrophobic layer / mass transfer channel of the GDL. The longer the operating time, the more severe the wear. The amount of mass transfer capacity reduction is positively correlated with the operating time. α is the dynamic mass transfer critical value reduction ratio obtained by fitting per hour of operation.

[0105] β×(130-θ) reflects the effect of the decrease in hydrophobicity of the gas diffusion layer on the mass transfer capacity: the oxygen removal capacity of the gas diffusion layer depends on its hydrophobicity (the larger the contact angle θ, the better the hydrophobicity, and the easier it is for oxygen to be removed from the surface of the gas diffusion layer). (130-θ) is the decrease in the current contact angle relative to the optimal hydrophobicity, and β is the proportion of dynamic mass transfer critical value decay caused by each 1° decrease in the contact angle obtained by fitting.

[0106] γ×(85-P): Reflects the impact of hydrophobic layer shedding in the gas diffusion layer on mass transfer capacity: PTFE is the core component of the hydrophobic layer in the gas diffusion layer. The higher the PTFE retention P, the more complete the hydrophobic layer and the stronger the oxygen removal capacity. (85-P) is the decrease in the current PTFE retention relative to the optimal hydrophobic layer. γ is the percentage decrease in the dynamic mass transfer critical value caused by each 1% decrease in the PTFE retention obtained by fitting.

[0107] It is understandable that the physical meaning of the dynamic mass transfer critical value decay model is: the dynamic mass transfer critical value of the gas diffusion layer (the maximum current density change amplitude without gas blockage under dynamic operating conditions) is the balance threshold between the oxygen removal capacity and oxygen generation rate of the gas diffusion layer. This oxygen removal capacity will gradually decrease as the gas diffusion layer continues to age and the operating time accumulates. The model quantitatively binds the three core physical characteristics of gas diffusion layer aging with the decay of the dynamic mass transfer critical value, realizing the transformation from qualitative description of aging to quantitative prediction of mass transfer capacity.

[0108] It should be noted that the purpose of constructing the dynamic mass transfer critical value decay model is to correlate the physical characteristics of gas diffusion layer aging with the decay of dynamic mass transfer capacity into a quantifiable model, thereby upgrading from static data of a single test to trend prediction of GDL aging mass transfer decay, and providing mathematical support for subsequent real-time correction and pre-emptive prevention.

[0109] Test result correction module: Run the PEM electrolyzer to obtain the actual maximum current density, and compare and analyze it with the dynamic test maximum current density to determine whether the actual maximum current density matches the dynamic test maximum current density. If they do not match, call the dynamic mass transfer critical value decay model to correct the test maximum current density.

[0110] The process of determining whether the actual maximum current density matches the dynamic test maximum current density includes:

[0111] The electrolytic cell was run continuously for 72 hours. The stable maximum current density was collected every 12 hours using an electrical sensor, and the average value was taken as the actual maximum current density.

[0112] Calculate the deviation rate between the dynamic maximum current density obtained under dynamic operating conditions and the actual maximum current density, and compare it with the preset deviation rate. If the deviation rate is less than or equal to the preset deviation rate, the actual maximum current density matches the dynamic test maximum current density; otherwise, they do not match.

[0113] It should be noted that the preset deviation rate is a quantitative judgment threshold for determining whether the maximum current density of dynamic testing can represent the actual mass transfer capacity in actual operation. In essence, it is the maximum range of mass transfer capacity difference between the allowed test conditions and the actual operating conditions, and is set in combination with the operating scenario and the aging state of the gas diffusion layer.

[0114] The process of correcting the maximum current density of the test includes:

[0115] If they do not match, call the dynamic mass transfer critical value decay model to calculate the true dynamic mass transfer critical value under the current cumulative runtime.

[0116] Based on the correlation between the dynamic mass transfer critical value and the current density mutation amplitude, the optimal current density mutation amplitude for the current adaptation is obtained.

[0117] Corrected maximum current density for dynamic testing: Corrected maximum current density for dynamic testing = Maximum current density for dynamic testing × (True dynamic mass transfer critical value / Dynamic mass transfer critical value obtained from dynamic testing).

[0118] Understandably, the logic of the matching judgment is that the maximum current density of the dynamic test should be consistent with the stable maximum current density of the actual operation. If the deviation rate is greater than or equal to the preset deviation rate, it means that the parameters of the dynamic test do not match the real-time aging decay of GDL. The core of the correction is to replace the dynamic mass transfer critical value that is not updated in real time during the test with the real dynamic mass transfer critical value obtained by the decay model, and eliminate the deviation caused by the difference between the gas diffusion layer state during the test and the gas diffusion layer state during actual operation.

[0119] It should be noted that the purpose of the test result correction is to align the results of the dynamic test with the actual mass transfer capacity during operation, correct the current overestimation caused by the real-time aging of the gas diffusion layer not being adapted to the test parameters, and ensure that the test results can accurately reflect the actual operating performance of the PEM electrolyzer, providing a reliable basis for the optimization of the current operating parameters.

[0120] Prediction parameter correction module: If a match is found, the dynamic mass transfer critical value for future periodic performance tests is predicted based on the dynamic mass transfer critical value decay model, mismatch tests are located, and the test parameters for mismatch tests are corrected.

[0121] The process of the positioning mismatch test includes:

[0122] Based on the current performance testing cycle of the PEM electrolyzer, the cumulative runtime of the nth periodic test is t. n =n × test period;

[0123] Call the dynamic mass transfer critical value decay model to predict the dynamic mass transfer critical value for each periodic performance test;

[0124] For any given periodic performance test:

[0125] Calculate the decay rate of the predicted dynamic mass transfer critical value relative to the current actual dynamic mass transfer critical value to obtain the predicted decay rate: Predicted decay rate = (Current actual dynamic mass transfer critical value - Predicted dynamic mass transfer critical value) / Current actual dynamic mass transfer critical value.

[0126] When the predicted decay rate is greater than or equal to the preset decay rate, and the current test parameters do not match the predicted dynamic mass transfer critical value, the periodic performance test will be marked as a mismatch test.

[0127] The process of correcting the test parameters for the mismatch test includes:

[0128] The correction value for the magnitude of the current density change is the dynamic mass transfer critical value predicted by the decay model at the mismatch test time point, which is the limit of the oxygen removal capacity of the gas diffusion layer at that time point in the future.

[0129] Adjust the load switching time based on the predicted contact angle from the mismatch test. ,in, The static contact angle of the gas diffusion layer at the mismatch test time point predicted by the attenuation model;

[0130] Adjust the low-load duration based on the gas permeability predicted by the model for this test: , where k pred The gas permeability of the gas diffusion layer at the mismatch test time point predicted by the attenuation model represents the future mass transfer channel width of the gas diffusion layer.

[0131] It is understandable that the prediction logic of the mismatch test is that when the dynamic mass transfer critical value of the gas diffusion layer decays to a value greater than or equal to the preset decay rate, the test parameters that were originally adapted to the current gas diffusion layer will no longer be adapted to the decayed gas diffusion layer, resulting in test parameter mismatch.

[0132] The core of pre-correction of parameters is to adapt the test parameters to the predicted aging state of the gas diffusion layer in advance, so as to avoid using old parameters in subsequent tests and causing misjudgment of the maximum current density. Essentially, it is to turn post-correction into pre-prevention.

[0133] It should be noted that the role of mismatch test location and parameter pre-correction is as follows: based on the decay model, predict the decay of the gas diffusion layer mass transfer capacity in future periodic tests, locate mismatch tests that will result in parameter mismatch in advance, and pre-correct the test parameters to avoid overestimation of the maximum current density in the future. This realizes the upgrade from correcting test deviations after the fact to preventing test mismatch in advance, and ensures the accuracy of long-term test results.

[0134] The technical solution and advantages of this application are as follows: Water flow velocity sensitivity testing is conducted under current static testing conditions, and the test results are compared and analyzed to determine if a test mismatch exists. If a mismatch exists, a test is conducted under dynamic operating parameters to obtain the dynamic maximum current density, which is then compared and analyzed with the static maximum current density to determine if the test mismatch is caused by dynamic mass transfer limitations. If so, the dynamic mass transfer critical value of the gas diffusion layer is determined through a gradient test of the current density abrupt change amplitude. Based on historical operating data of the PEM electrolyzer, a dynamic mass transfer critical value decay model is constructed. The actual maximum current density is obtained by running the PEM electrolyzer and compared and analyzed with the dynamic test maximum current density to determine if the actual maximum current density matches the dynamic test maximum current density. If they do not match, the dynamic mass transfer critical value decay model is invoked to correct the tested maximum current density. If they match, the dynamic mass transfer critical value decay model is used to predict the dynamic mass transfer critical value for future periodic performance tests, locate the mismatch test, and correct the test parameters for the mismatch test. This invention identifies the overestimation of maximum current density through water flow velocity sensitivity testing, and clarifies the dynamic mass transfer limitations and the dynamic mass transfer critical value of the gas diffusion layer through dynamic operating condition testing adapted to actual operating scenarios via dynamic mass transfer verification. Based on historical data, it quantifies the aging decay law of the dynamic mass transfer critical value of the gas diffusion layer, corrects the test deviation of mismatched gas diffusion layer real-time aging through actual operation verification, and pre-locates and corrects future parameter mismatch tests through mismatch test prediction and parameter correction. This solves the problem of overestimation of maximum current density caused by existing static tests that do not consider the dynamic mass transfer limitations and aging effects of the gas diffusion layer. It achieves dynamic adaptation of the gas diffusion layer aging state and test parameters, reducing the deviation between test results and actual operation.

[0135] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A performance testing system for a PEM electrolyzer, characterized in that: Includes the following modules: Test mismatch determination module: Performs water flow velocity sensitivity test under the current static test conditions, and determines whether there is a test mismatch by comparing and analyzing the test results; Dynamic mass transfer verification module: If it exists, test under dynamic operating conditions to obtain the dynamic maximum current density, and compare and analyze it with the static maximum current density to determine whether the test mismatch is caused by dynamic mass transfer limitation. If so, determine the dynamic mass transfer critical value of the gas diffusion layer by the current density change amplitude gradient test. Attenuation model construction module: Based on historical operating data of PEM electrolyzers, a dynamic mass transfer critical value attenuation model is constructed; Test result correction module: Run the PEM electrolyzer to obtain the actual maximum current density, and compare and analyze it with the dynamic test maximum current density to determine whether the actual maximum current density matches the dynamic test maximum current density. If they do not match, call the dynamic mass transfer critical value decay model to correct the test maximum current density. Prediction parameter correction module: If a match is found, the dynamic mass transfer critical value for future periodic performance tests is predicted based on the dynamic mass transfer critical value decay model, mismatch tests are located, and the test parameters for mismatch tests are corrected.

2. The performance testing system for a PEM electrolyzer according to claim 1, characterized in that: The method for determining whether a test mismatch exists is as follows: Keep all static test conditions constant, including temperature, pressure, and load as a stepped constant current density, and only change the water flow rate; Two sets of tests were set up, including a benchmark test and a low water flow rate test. The benchmark test used the original constant water flow rate to test and record the static maximum current density. The low water flow rate test reduced the water flow rate by one gradient and tested under the same load step, recording the maximum current density at the low water flow rate. Calculate the deviation between the static maximum current density and the maximum current density at low water flow rate. If the deviation meets the requirements, then there is a test mismatch.

3. The performance testing system for a PEM electrolyzer according to claim 1, characterized in that: The method for determining whether the test mismatch is caused by dynamic mass transfer limitation is as follows: Set the dynamic operating condition test parameters to be the same as the actual operating conditions of the PEM electrolyzer, and conduct the test under the dynamic operating condition parameters to obtain the dynamic maximum current density. The static maximum current density, the maximum current density at low water flow rate, and the dynamic maximum current density of the gas diffusion layer are compared. If the dynamic maximum current density < the low water flow rate maximum current density < the static maximum current density, and air blockage characteristics appear in the dynamic test, but no air blockage appears in the static low water flow rate group, then the test mismatch is caused by dynamic mass transfer limitation. Among them, the characteristics of airlock include voltage changes and local temperature differences meeting the requirements.

4. The performance testing system for a PEM electrolyzer according to claim 3, characterized in that: The method for determining the presence of airlock characteristics in the dynamic test is as follows: During dynamic testing, the voltage and local temperature difference within the time window after the current density completes the low-load-high-load switching are monitored. The local temperature difference area is the gas diffusion layer area covered by the flow channel on the anode side of the gas diffusion layer and the gas diffusion layer area in the flow channel gap. Three consecutive dynamic cyclic tests were performed under the same current density abrupt change amplitude: If the voltage and local temperature difference both meet the requirements within the time window of the three cycles, it is determined that airlock characteristics have occurred in the dynamic test.

5. The performance testing system for a PEM electrolyzer according to claim 3, characterized in that: The dynamic operating condition test parameters are set as follows: Dynamic operating condition test parameters include current density change amplitude, load switching speed and time, cycle period and number of cycles, water flow rate, temperature and pressure; The current density fluctuation amplitude is taken as the 95th percentile load fluctuation amplitude in actual operation, and the load switching time is taken as the load switching response time in actual operation. The cycle period includes the low load duration = the actual low load stabilization time during operation, the high load duration = the actual high load stabilization time during operation, and the number of cycles is the actual daily average load cycle number during operation. The water flow rate, temperature, and pressure were consistent with those of the static test.

6. The performance testing system for a PEM electrolyzer according to claim 5, characterized in that: The process for determining the dynamic mass transfer critical value is as follows: Calculate the maximum difference in current density from low load to high load per unit time to obtain the maximum current density jump amplitude. Starting from the 95th percentile current density mutation amplitude in actual operation, gradually increase the current density mutation amplitude. Each time it is adjusted, perform 3 cycle tests under dynamic operating conditions to observe whether air blockage is triggered. The minimum current density change amplitude that triggers gas blockage for the first three consecutive cycles is the dynamic mass transfer critical value of the gas diffusion layer.

7. The performance testing system for a PEM electrolyzer according to claim 1, characterized in that: The construction process of the dynamic mass transfer critical value decay model includes: Obtain historical operating data of PEM electrolyzers, including: cumulative operating time of PEM electrolyzers, distribution of actual load fluctuation amplitude, constant water flow rate, and temperature and pressure fluctuation data; The dynamic mass transfer critical value of the gas diffusion layer is calculated, and a dynamic mass transfer critical value decay model is constructed with the cumulative running time as the independent variable and the historical dynamic mass transfer critical value as the dependent variable. ; in, α is the initial dynamic mass transfer critical value of the new gas diffusion layer, t is the cumulative running time, and α is the rate of decrease of the dynamic mass transfer critical value per hour of running obtained by fitting. 130-θ is the decrease in the current contact angle relative to the optimal hydrophobicity, and β is the percentage decrease in the dynamic mass transfer critical value for every 1° decrease in the fitted contact angle; 85-P represents the decrease in PTFE retention relative to the optimal hydrophobic layer, and γ is the percentage decrease in the critical mass transfer value caused by each 1% decrease in PTFE retention obtained from the fitting.

8. The performance testing system for a PEM electrolyzer according to claim 1, characterized in that: The method for determining whether the actual maximum current density matches the dynamic test maximum current density is as follows: Run the electrolytic cell continuously for one cycle, record the stable maximum current density in each small cycle, and take the average value as the actual maximum current density. Calculate the deviation rate between the dynamic maximum current density obtained under dynamic operating conditions and the actual maximum current density. If the deviation rate meets the requirements, the actual maximum current density matches the dynamic test maximum current density; otherwise, they do not match.

9. The performance testing system for a PEM electrolyzer according to claim 8, characterized in that: The process of correcting the maximum current density of the test is as follows: If they do not match, call the dynamic mass transfer critical value decay model to calculate the true dynamic mass transfer critical value under the current cumulative runtime. Corrected maximum current density for dynamic testing: Corrected maximum current density for dynamic testing = Maximum current density for dynamic testing × (True dynamic mass transfer critical value / Dynamic mass transfer critical value obtained from dynamic testing).

10. The performance testing system for a PEM electrolyzer according to claim 1, characterized in that: The prediction method for the dynamic mass transfer critical value of the future periodic performance test is as follows: Based on the current performance testing cycle of the PEM electrolyzer, the cumulative runtime of the nth periodic test is t. n =n × test period; The dynamic mass transfer critical value decay model is invoked to predict the dynamic mass transfer critical value for each periodic performance test.

11. The performance testing system for a PEM electrolyzer according to claim 10, characterized in that: The method for the positioning mismatch test is as follows: For any periodic performance test, calculate the decay rate of the predicted dynamic mass transfer critical value relative to the current actual dynamic mass transfer critical value to obtain the predicted decay rate: Predicted decay rate = (Current actual dynamic mass transfer critical value - Predicted dynamic mass transfer critical value) / Current actual dynamic mass transfer critical value. When the predicted decay rate meets the requirements, and the current test parameters do not match the predicted dynamic mass transfer critical value, the periodic performance test will be marked as a mismatch test.

12. The performance testing system for a PEM electrolyzer according to claim 11, characterized in that: The process of correcting the test parameters for the mismatch test is as follows: The correction value for the magnitude of the current density change is the dynamic mass transfer critical value predicted by the decay model at the mismatch test time point, which is the limit of the oxygen removal capacity of the gas diffusion layer at that time point in the future. Adjust the load switching time based on the predicted contact angle from the mismatch test. ,in, The static contact angle of the gas diffusion layer at the mismatch test time point is predicted by the attenuation model.

13. The performance testing system for a PEM electrolyzer according to claim 12, characterized in that: The process of correcting the test parameters for mismatch testing also includes: Adjust the low-load duration based on the gas permeability predicted by the model for this test: , where k pred This represents the gas permeability of the gas diffusion layer at the mismatch test time point predicted by the attenuation model.

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