A rapid calculation method for the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions

Abstract

The present invention discloses a rapid calculation method for the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions, belonging to the technical field of fuel cell durability tests. A constant-speed durability test of the first fuel cell is carried out under actual vehicle conditions, and a single-condition accelerated durability test is carried out on the second fuel cell. The thicknesses of the catalyst layers of the membrane electrodes of the third fuel cell, the first post-test fuel cell obtained after the constant-speed durability test under actual vehicle conditions, and the second post-test fuel cell obtained after the single-condition accelerated durability test are measured respectively, and then the acceleration factor used to characterize the correlation between the single-condition accelerated durability test and the constant-speed durability test under actual vehicle conditions can be determined. By using the acceleration factor, the life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions can be quickly inferred, and the calculation efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell durability testing, and particularly to a method for rapidly calculating the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions. Background Art

[0002] In recent years, with the acceleration of the commercialization process of fuel cell vehicles, the life of fuel cells has become one of the key concerns in the fuel cell vehicle industry. As the core component of a fuel cell, the life of the membrane electrode directly determines the life of the fuel cell. However, under actual vehicle conditions, the fuel cell performance degradation test often requires thousands of hours, which is difficult to meet the rapid detection requirements for the durability of the membrane electrode.

[0003] Based on this, there is an urgent need for a method that can rapidly calculate the life of a fuel cell membrane electrode under actual vehicle conditions. Summary of the Invention

[0004] The object of the present invention is to provide a method for rapidly calculating the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions. By calculating the acceleration factor that characterizes the correlation between a single-condition accelerated durability test and a constant-speed durability test under actual vehicle conditions, the life of the fuel cell membrane electrode under actual vehicle conditions can be rapidly calculated, and the calculation efficiency is high.

[0005] To achieve the above object, the present invention provides the following solution:

[0006] A method for rapidly calculating the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions, the rapid calculation method comprising:

[0007] Conduct a constant-speed durability test on a first fuel cell under actual vehicle conditions until the first performance degradation rate of the first fuel cell reaches a preset value, obtaining a first post-test fuel cell and a first operating time;

[0008] Conduct a single-condition accelerated durability test on a second fuel cell until the second performance degradation rate of the second fuel cell reaches the preset value, obtaining a second post-test fuel cell and a second operating time;

[0009] Measure the thicknesses of the catalyst layers of the membrane electrodes of a third fuel cell, the first post-test fuel cell, and the second post-test fuel cell respectively, obtaining a reference thickness, a first thickness, and a second thickness;

[0010] Calculate the acceleration factor according to the first performance degradation rate, the first operating time, the second performance degradation rate, the second operating time, the reference thickness, the first thickness, and the second thickness; the acceleration factor is used to characterize the correlation between the single-condition accelerated durability test and the constant-speed durability test under actual vehicle conditions, and calculate the life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions.

[0011] In some embodiments, the performing of a normal speed endurance test on the first fuel cell under actual vehicle operating conditions until a first performance attenuation rate of the first fuel cell reaches a preset value, and obtaining the first post-test fuel cell and the first operating time specifically includes:

[0012] activating the first fuel cell to obtain a first activated fuel cell; retesting the performance of the first activated fuel cell to obtain a first polarization curve;

[0013] Running a first operating curve several times on the first activated fuel cell to obtain a first operated fuel cell;

[0014] Performing reversible loss recovery on the first operating fuel cell to obtain a first recovered fuel cell; retesting the performance of the first recovered fuel cell to obtain a second polarization curve;

[0015] determining a first performance decay rate of the first fuel cell according to the first polarization curve and the currently obtained second polarization curve, and judging whether the first performance decay rate reaches a preset value;

[0016] If yes, then the actual vehicle operating condition constant speed endurance test is terminated, the first recovered fuel cell is used as the first post-test fuel cell, and the total operation time of the first operating condition curve in the actual vehicle operating condition constant speed endurance test is determined to obtain a first operation time;

[0017] If not, continue the actual vehicle operating condition normal speed endurance test, use the first restored fuel cell as the first activated fuel cell, and return to the step of "running the first operating condition curve several times on the first activated fuel cell to obtain the first operating fuel cell".

[0018] In some embodiments, the performing of a single-operating-condition accelerated endurance test on the second fuel cell until the second performance attenuation rate of the second fuel cell reaches the preset value, and obtaining the second post-test fuel cell and the second operating time specifically includes:

[0019] activating the second fuel cell to obtain a second activated fuel cell; retesting the performance of the second activated fuel cell to obtain a third polarization curve;

[0020] Running a second operating curve several times on the second activated fuel cell to obtain a second operated fuel cell;

[0021] Performing reversible loss recovery on the second operating fuel cell to obtain a second recovered fuel cell; retesting the performance of the second recovered fuel cell to obtain a fourth polarization curve;

[0022] determining a second performance decay rate of the second fuel cell according to the third polarization curve and the currently obtained fourth polarization curve, and judging whether the second performance decay rate is greater than the preset value;

[0023] If yes, then the single-operating-condition accelerated endurance test is terminated, the second recovered fuel cell is used as the second post-test fuel cell, and the total operating time of the second operating condition curve in the single-operating-condition accelerated endurance test is determined to obtain a second operating time;

[0024] If not, continue the single operating condition accelerated endurance test, use the second restored fuel cell as the second activated fuel cell, and return to the step of "running the second operating condition curve several times on the second activated fuel cell to obtain a second operating fuel cell".

[0025] In some embodiments, the test fixture and test conditions used in the single-operating-condition accelerated endurance test and the actual-vehicle-operating-condition normal-speed endurance test are the same; the activation method and activation end judgment condition used for activating the first fuel cell and the second fuel cell are the same; the performance retest of the first activated fuel cell, the performance retest of the first recovered fuel cell, the performance retest of the second activated fuel cell, and the performance retest of the second recovered fuel cell are the same; the reversible loss recovery of the first operating fuel cell and the reversible loss recovery of the second operating fuel cell are the same.

[0026] In some embodiments, the second operating condition curve is a triangular wave voltage curve.

[0027] In some embodiments, the method for measuring the thickness of the catalyst layer of the membrane electrode comprises:

[0028] A triple ion beam cutter is used to cut multiple sampling positions of the membrane electrode respectively, and a scanning electron microscope is used to take a cross-sectional photograph corresponding to each sampling position to determine the thickness of the catalyst layer at each sampling position; the average value of the thickness of the catalyst layer at all the sampling positions is calculated to obtain the thickness of the catalyst layer of the membrane electrode; the membrane electrode is the membrane electrode of the third fuel cell, the first post-test fuel cell and the second post-test fuel cell.

[0029] In some embodiments, calculating the acceleration factor according to the first performance decay rate, the first operating time, the second performance decay rate, the second operating time, the reference thickness, the first thickness, and the second thickness specifically includes:

[0030] Calculate the first thickness attenuation rate of the first fuel cell based on the reference thickness and the first thickness; calculate the second thickness attenuation rate of the second fuel cell based on the reference thickness and the second thickness;

[0031] Calculate the contribution factor based on the first performance attenuation rate, the second performance attenuation rate, the first thickness attenuation rate, and the second thickness attenuation rate;

[0032] Calculate the acceleration factor based on the first operating time, the second operating time, and the contribution factor.

[0033] In some embodiments, the calculation formula for the contribution factor is:

[0034]

[0035] where σ is the contribution factor; c is the second performance attenuation rate; b is the first thickness attenuation rate; a is the first performance attenuation rate; d is the second thickness attenuation rate.

[0036] In some embodiments, the calculation formula for the acceleration factor is:

[0037]

[0038] where ε is the acceleration factor; σ is the contribution factor; t 1 is the first operating time; t 2 is the second operating time.

[0039] In some embodiments, calculating the service life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions specifically includes:

[0040] Conduct a single-condition accelerated durability test on the fuel cell to be tested to determine the service life of the membrane electrode of the fuel cell to be tested under a single condition; use the acceleration factor to correct the service life under the single condition to obtain the service life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions.

[0041] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0042] The present invention is used to provide a method for quickly calculating the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions. A constant-speed durability test of the first fuel cell under actual vehicle conditions is carried out, and a single-condition accelerated durability test of the second fuel cell is carried out. The thicknesses of the catalyst layers of the membrane electrodes of the third fuel cell, the first post-test fuel cell obtained after the constant-speed durability test under actual vehicle conditions, and the second post-test fuel cell obtained after the single-condition accelerated durability test are measured respectively, and then the acceleration factor used to characterize the correlation between the single-condition accelerated durability test and the constant-speed durability test under actual vehicle conditions can be determined. By using the acceleration factor, the life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions can be quickly inferred, so that the life of the fuel cell membrane electrode under actual vehicle conditions can be quickly predicted, and the prediction efficiency is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0044] Figure 1 It is the flowchart of the quick calculation method provided by Embodiment 1 of the present invention;

[0045] Figure 2 It is the calculation principle diagram of the acceleration factor provided by Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0047] The purpose of the present invention is to provide a method for quickly calculating the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions. By calculating the acceleration factor that characterizes the correlation between the single-condition accelerated durability test and the constant-speed durability test under actual vehicle conditions, the life of the fuel cell membrane electrode under actual vehicle conditions can be quickly calculated, and the calculation efficiency is high.

[0048] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0049] Embodiment 1:

[0050] Considering that the single-condition accelerated durability test for a single factor of the membrane electrode can quickly determine the service life of the membrane electrode under a single condition, but the service life of the membrane electrode under a single condition does not correspond to the actual life of the multi-factor conditions faced by the fuel cell vehicle in actual operation, and there is no connection between the current single-condition accelerated durability test and the constant-speed durability test of the vehicle operating conditions. Therefore, establishing the connection between the single-condition accelerated durability test of a single factor of the membrane electrode and the constant-speed durability test of the multi-factor vehicle operating conditions is of great significance for quickly determining the life of the membrane electrode under the vehicle operating conditions and evaluating the durability of the fuel cell.

[0051] Based on this, this embodiment is used to provide a method for quickly calculating the acceleration factor of a fuel cell membrane electrode under vehicle operating conditions, as Figure 1 and Figure 2 shown, the quick calculation method includes:

[0052] S1: Conduct a constant-speed durability test on the first fuel cell under vehicle operating conditions until the first performance decay rate of the first fuel cell reaches a preset value, and obtain the first fuel cell after the test and the first running time;

[0053] Specifically, S1 may include:

[0054] (1) Activate the first fuel cell to obtain the first fuel cell after activation; conduct a performance retest on the first fuel cell after activation to obtain the first polarization curve.

[0055] The performance retest in this embodiment refers to the polarization curve test. The polarization curve test process includes applying different currents to the battery and collecting the voltage of the battery at each current to plot the polarization curve of the voltage changing with the current.

[0056] (2) Run the first condition curve several times on the first fuel cell after activation to obtain the first fuel cell after running.

[0057] This embodiment adopts the power output ratio of the actual vehicle operation process to formulate the working condition spectrum, specifically converting the power output spectrum curve based on the actual road working condition of China's heavy-duty vehicles into the first working condition curve used in the normal speed endurance test of the actual vehicle working condition. The first working condition curve is a curve of output power changing with time, and its maximum output power is 100% PE, PE refers to the rated power, the low power range (10% PE, 30% PE, 40% PE) accounts for 33.9% in total, and the high power range (60% PE, 80% PE, 100% PE) accounts for 66.1% in total. According to the first working condition curve, the corresponding power is applied to the first activated fuel cell to run the first working condition curve on the first activated fuel cell. The first working condition curve has a complete running time of 30 minutes. This embodiment can run 24 working condition curves each time, that is, 24 first working condition curves are run on the first activated fuel cell, and the time is 12 hours. In this embodiment, the performance retest can be performed every 12 hours, that is, the polarization curve test is performed after running for 12 hours, 24 hours, 36 hours, ... (incremented by 12 hours), so as to perform the polarization curve test at a suitable position.

[0058] (3) performing reversible loss recovery on the first operating fuel cell to obtain a first recovered fuel cell; and retesting the performance of the first recovered fuel cell to obtain a second polarization curve.

[0059] (4) Determine a first performance degradation rate of the first fuel cell according to the first polarization curve and the currently obtained second polarization curve, and judge whether the first performance degradation rate reaches a preset value.

[0060] This embodiment randomly defines a reference current, determines the first voltage corresponding to the reference current according to the first polarization curve, determines the second voltage corresponding to the reference current according to the current second polarization curve, calculates the difference between the first voltage and the second voltage, and calculates the ratio of the difference to the first voltage, and the first performance attenuation rate can be obtained. The predetermined value may be greater than or equal to 10%. Specifically, the calculation formula for the first performance attenuation rate is: m = (Ei-E0) / E0, where m is the first performance attenuation rate, Ei is the second voltage corresponding to the reference current selected by the second polarization curve, E0 is the first voltage corresponding to the reference current selected by the first polarization curve, and the first polarization curve and the second polarization curve use the same reference current.

[0061] (5) If so, the actual vehicle operating condition constant speed endurance test is terminated, the first post-recovery fuel cell is used as the first post-test fuel cell, and the total operating time of the first operating condition curve in the actual vehicle operating condition constant speed endurance test is determined to obtain the first operating time.

[0062] Polarization curve tests were performed before the start of the cycle and after every 12 h of cycling until the performance decay reached 10%. The cycle duration at this time was recorded as the first running time.

[0063] (6) If not, continue the normal speed endurance test under actual vehicle operating conditions, use the first restored fuel cell as the first activated fuel cell, and return to the step of "running the first operating condition curve several times on the first activated fuel cell to obtain the first operated fuel cell".

[0064] S2: performing a single-operating-condition accelerated endurance test on the second fuel cell until a second performance attenuation rate of the second fuel cell reaches the preset value, and obtaining a second fuel cell after the test and a second operating time;

[0065] Specifically, S2 may include:

[0066] (1) Activating the second fuel cell to obtain a second activated fuel cell; and retesting the performance of the second activated fuel cell to obtain a third polarization curve.

[0067] (2) Running the second operating curve several times on the second activated fuel cell to obtain a second operated fuel cell.

[0068] In this embodiment, the second operating condition curve can be a triangular wave voltage curve, using a triangular wave varying between 1.0V and 1.5V as the voltage curve, the operating time of a complete operation of the second operating condition curve is 2s, and the voltage change rate is 0.5V / s. A voltage is applied to the second activated fuel cell according to the voltage curve to operate the second operating condition curve on the second activated fuel cell. In this embodiment, a polarization curve test can be performed after 10, 100, 200, 500, 1000, 1500, ... (increased by 500), 4500, 5000 cycles, that is, during the first operation, the second operating condition curve is run 10 times; during the second operation, the second operating condition curve is run 100 times, and so on, so as to perform a polarization curve test at a suitable position. In this embodiment, an accelerated endurance test condition for membrane electrode catalyst carrier attenuation based on the DOE test procedure is adopted, and a method of triangular wave voltage scanning at a voltage scanning rate of 500mV / s between 1.0V and 1.5V is adopted to achieve rapid degradation of the catalyst carrier. Each completion of the whole process from 1.0V to 1.5V and back to 1.0V is one cycle, and each cycle is 2s. Polarization curve tests are performed before the start of the cycle and after each 10, 50, 100, 200, 500, 1000, 1500, 2000... times.

[0069] (3) performing reversible loss recovery on the second operating fuel cell to obtain a second recovered fuel cell; and retesting the performance of the second recovered fuel cell to obtain a fourth polarization curve.

[0070] (4) Determine a second performance degradation rate of the second fuel cell according to the third polarization curve and the currently obtained fourth polarization curve, and judge whether the second performance degradation rate reaches a preset value.

[0071] In this embodiment, a reference current is randomly defined. The third voltage corresponding to the reference current is determined according to the third polarization curve, the fourth voltage corresponding to the reference current is determined according to the current fourth polarization curve, the difference between the third voltage and the fourth voltage is calculated, and the ratio of the difference to the third voltage is calculated, thereby obtaining the second performance degradation rate. It should be noted that the same reference current is selected for the third polarization curve and the fourth polarization curve as for the first polarization curve and the second polarization curve.

[0072] (5) If so, end the single-condition accelerated durability test, use the second restored fuel cell as the second post-test fuel cell, and determine the total running time of the second-condition curve in the single-condition accelerated durability test to obtain the second running time.

[0073] In this embodiment, during the single-condition accelerated durability test, the cycle duration at this time can be recorded as the second running time. Preferably, according to all the fourth polarization curves, a curve of the fourth voltage corresponding to the reference current at different times can be fitted to obtain a curve equation with the number of cycles as the horizontal axis and the fourth voltage corresponding to the reference current as the vertical axis. Substitute the voltage corresponding to the first performance degradation rate into the above curve equation to obtain the number of cycles, and multiply the number of cycles by the duration of one cycle (2 s) to obtain the second running time t 2 。

[0074] (6) If not, continue the single-condition accelerated durability test, use the second restored fuel cell as the second post-activation fuel cell, and return to the step of "running the second-condition curve a certain number of times on the second post-activation fuel cell to obtain the second post-running fuel cell".

[0075] Preferably, in this embodiment, the first fuel cell and the second fuel cell are products of the same manufacturer and the same batch to avoid the influence of product differences on the test results.

[0076] The test fixtures and test conditions used in the single-condition accelerated durability test and the in-vehicle condition constant-speed durability test are the same. When conducting the durability test, the membrane electrode needs to be assembled into a single cell. The single cells for the two durability tests adopt the same assembly scheme, and a test fixture is used to fix the single cell. The durability test is carried out with the single cell as the test carrier. The test fixture includes an end plate, a current collector plate, a flow field plate, fastening screws, etc. The test conditions are that the temperature of the single cell is 80 °C, and both the anode and cathode of the single cell are in a 100% RH humidification state to avoid the influence of temperature and humidity changes on the performance of the membrane electrode.

[0077] In this embodiment, both the single-condition accelerated durability test and the in-vehicle condition constant-speed durability test use an anode / cathode platinum loading of 0.1 / 0.4 mg / cm 2The membrane electrode samples are assembled into single cells using a single serpentine flow field fixture for testing. The fuel cell single cell test platform model used can be the TOYO Fuel Cell Test System, which provides a certain flow of hydrogen, air, and nitrogen required for fuel cell testing to meet the temperature and humidity control requirements, and meets the current and voltage control conditions through the load and electrochemical workstation modules, and outputs and saves the test results. The test process controls the temperature of the single cell to 80°C and the anode gas to H 2 , the cathode gas is N 2 , the relative humidity of the gas is 100% RH.

[0078] The activation method and activation end judgment condition used for activating the first fuel cell and the second fuel cell are the same, that is, the single-condition accelerated endurance test and the actual vehicle condition constant speed endurance test are implemented with the same activation method and the same activation end judgment condition, and the activation end judgment end condition can be that the voltage difference at the corresponding current point when the voltage is about 0.5V is not greater than 2mV after two consecutive load increases to the current point and stabilization for 20 minutes. After activation, the single cell performance of the first activated fuel cell and the second activated fuel cell is basically the same.

[0079] The methods for retesting the performance of the fuel cell after the first activation, retesting the performance of the fuel cell after the first recovery, retesting the performance of the fuel cell after the second activation, and retesting the performance of the fuel cell after the second recovery are the same, that is, the single-condition accelerated endurance test and the actual vehicle condition normal-speed endurance test use the same polarization curve test method.

[0080] The method for reversible loss recovery of the fuel cell after the first operation is the same as the method for reversible loss recovery of the fuel cell after the second operation, that is, the same reversible loss recovery method is used for the single-operating accelerated endurance test and the actual vehicle operating condition normal speed endurance test. Specifically, N can be alternately passed to the anode / cathode 2 / N 2 ,NA / air,N 2 / N 2 , H 2 / NA,H 2 / air, to recover the reversible loss. NA means no ventilation, that is, N is first passed to the anode. 2 , cathode is N 2 , then no air is ventilated to the anode, air is ventilated to the cathode, and then N is ventilated to the anode. 2 , cathode is N 2 , then pass H to the anode 2 , the cathode is not ventilated, and finally H is passed to the anode 2 , air is passed through the cathode, and the time and flow rate of each gas can be defined by yourself.

[0081] S3: Measure the thicknesses of the catalyst layers of the membrane electrodes of the third fuel cell, the first post-test fuel cell, and the second post-test fuel cell respectively to obtain a reference thickness, a first thickness, and a second thickness.

[0082] In this embodiment, the method for measuring the thickness of the catalyst layer of the membrane electrode includes: using a triple ion beam cutting instrument to cut multiple sampling positions of the membrane electrode respectively, taking cross-section photos of the smooth cutting cross-sections corresponding to each sampling position with a scanning electron microscope, so as to determine the thickness of the catalyst layer at each sampling position according to the cross-section photos. Then calculate the average value of the thicknesses of the catalyst layers at all sampling positions to obtain the thickness of the catalyst layer of the membrane electrode, reduce the influence of uneven attenuation at different positions on the calculation result, and thus observe the attenuation of the catalyst layer thickness through the microstructure to obtain the contribution factor of the catalyst carrier attenuation to the durability attenuation under the actual vehicle operating conditions. The thickness of the catalyst layer generally refers to the thickness of the catalyst layer on the cathode side. The membrane electrode can be the membrane electrode of the third fuel cell, the first post-test fuel cell, and the second post-test fuel cell.

[0083] Among them, the equipment model of the triple ion beam cutting instrument can be Leica EM TIC 3X, and the equipment model of the scanning electron microscope can be the Zeiss EVO series tungsten filament scanning electron microscope. The sampling positions can be the air inlet, hydrogen inlet, air outlet, hydrogen outlet, and the central position of the membrane electrode. For the third fuel cell, regardless of the flow field direction and the direction perpendicular to the flow field, a 1 cm × 0.5 cm area in the middle of the membrane electrode is directly used as the central position. For the first post-test fuel cell and the second post-test fuel cell, the central position is within a 1 cm × 0.5 cm area in the flow field direction. The flow field direction is the long side of the sampling area, and the observation cross-section is perpendicular to the flow field direction.

[0084] In this embodiment, cross-section microstructure observations are respectively carried out on fuel cells in the factory state without damage and without undergoing tests, fuel cells after accelerated durability tests, and fuel cells after constant-speed durability tests of the membrane electrode, so as to obtain the reference thickness of the third fuel cell, the first thickness of the first post-test fuel cell, and the second thickness of the second post-test fuel cell, which is convenient for subsequent determination of the correlation.

[0085] Through S1 - S3, this embodiment obtains the data required for establishing the durability correlation, including the accelerated durability test data of the membrane electrode catalyst carrier based on the triangular wave, the constant-speed durability test data of the membrane electrode based on the actual vehicle conditions, and the thickness change data of the catalyst layer collected when the membrane electrode is in the unused factory state, after the accelerated durability test, and after the constant-speed durability test. Subsequently, the correlation between the single-condition accelerated durability test and the actual vehicle condition constant-speed durability test is established based on the data trends of the above data.

[0086] S4: Calculate an acceleration factor based on the first performance decay rate, the first running time, the second performance decay rate, the second running time, the reference thickness, the first thickness, and the second thickness; the acceleration factor is used to characterize the correlation between the single-condition accelerated durability test and the in-vehicle condition constant-speed durability test, and calculate the life of the membrane electrode of the fuel cell to be tested under in-vehicle conditions.

[0087] When the performance decay rates of the in-vehicle condition constant-speed durability test and the single-condition accelerated durability test are almost the same, determine the thickness decay rate of the catalyst layer through microstructure characterization means to evaluate the contribution factor of the single condition in the in-vehicle condition decay, and obtain the initial acceleration factor through the running duration, and then couple the initial acceleration factor and the contribution factor to infer the relationship between the life under the single condition and the life under the in-vehicle condition. The above process may include: in the in-vehicle condition constant-speed durability test, when the decay ratio (i.e., the first performance decay rate) of the voltage corresponding to the reference current determined by the polarization curve reaches a% (generally a≥10), determine the thickness decay ratio (i.e., the first thickness decay rate) b% of the catalyst layer of the fuel cell after the first test through membrane electrode microstructure analysis; in the single-condition accelerated durability test for the catalyst support, when the decay ratio (i.e., the second performance decay rate) of the voltage corresponding to the reference current determined by the polarization curve reaches a%, record the second performance decay rate c% at this time, and determine the thickness decay ratio (i.e., the second thickness decay rate) d% of the catalyst layer of the fuel cell after the second test through membrane electrode microstructure analysis; respectively record the first running time t 1 of the in-vehicle condition constant-speed durability test and the second running time t 2 of the single-condition accelerated durability test, and the initial acceleration factor δ = t 1 / t 2 ; the decay from the catalyst support in the in-vehicle condition constant-speed decay is calculated using the contribution factor σ = cb / ad; the acceleration factor of the fuel cell catalyst support durability test corrected according to the contribution factor is ε = σ·δ = cbt 1 / adt 2 .

[0088] Specifically, S4 may include:

[0089] (1) Calculate the first thickness decay rate of the first fuel cell based on the reference thickness and the first thickness; calculate the second thickness decay rate of the second fuel cell based on the reference thickness and the second thickness.

[0090] Calculate the difference between the reference thickness and the first thickness, and calculate the ratio of the difference to the reference thickness to obtain the first thickness decay rate. Calculate the difference between the reference thickness and the second thickness, and calculate the ratio of the difference to the reference thickness to obtain the second thickness decay rate.

[0091] (2) Calculate the contribution factor according to the first performance decay rate, the second performance decay rate, the first thickness decay rate, and the second thickness decay rate.

[0092] The calculation formula for the contribution factor is:

[0093]

[0094] Where σ is the contribution factor; c is the second performance decay rate; b is the first thickness decay rate; a is the first performance decay rate; d is the second thickness decay rate.

[0095] (3) Calculate the acceleration factor according to the first running time, the second running time, and the contribution factor.

[0096] The calculation formula for the initial acceleration factor is:

[0097]

[0098] Where δ is the initial acceleration factor, t 1 is the first running time; t 2 is the second running time.

[0099] The calculation formula for the acceleration factor is:

[0100]

[0101] Where ε is the acceleration factor; σ is the contribution factor; δ is the initial acceleration factor; t 1 is the first running time; t 2 is the second running time; c is the second performance decay rate; b is the first thickness decay rate; a is the first performance decay rate; d is the second thickness decay rate.

[0102] In this embodiment, a specific test on the acceleration factor of the durability test of the fuel cell catalyst support is carried out, and the test results are shown in the following table:

[0103]

[0104] This embodiment provides a method for correlating fuel cell durability tests. During the operation of the accelerated durability condition based on a single factor of membrane electrode catalyst support degradation, polarization curve tests are conducted. During the operation of the constant-speed durability condition based on the actual vehicle condition, polarization curve tests are conducted to determine the cross-sectional change diagrams of the catalyst layer of the fuel cell membrane electrode in the factory state, after accelerated durability, and after constant-speed durability. By means of the law of the change in microstructure and the trend of performance decay, the connection between the single-condition single-factor accelerated durability test of the fuel cell membrane electrode and the multi-factor constant-speed durability test of the actual vehicle condition is established, and the acceleration factor of the performance decay of the single-factor accelerated durability test on the multi-factor constant-speed durability of the actual vehicle condition is inferred, so as to solve the technical problem that the measured life of the single-condition durability test for a single factor cannot correspond to the actual life of the multi-factor constant-speed condition faced by the fuel cell during actual vehicle operation, and the life of the fuel cell membrane electrode under the actual vehicle condition can be quickly determined.

[0105] Specifically, calculating the life of the membrane electrode of the fuel cell to be tested under the actual vehicle condition may include: conducting a single-condition accelerated durability test on the fuel cell to be tested to determine the life of the membrane electrode of the fuel cell to be tested under the single condition; using the acceleration factor to correct the life under the single condition to obtain the life of the membrane electrode of the fuel cell to be tested under the actual vehicle condition.

[0106] Among them, using the acceleration factor to correct the life under the single condition to obtain the life of the membrane electrode of the fuel cell to be tested under the actual vehicle condition may include: calculating the product of the acceleration factor and the life under the single condition to obtain the life of the membrane electrode of the fuel cell to be tested under the actual vehicle condition.

[0107] The proton exchange membrane fuel cell uses hydrogen as fuel and has the advantages of being clean, pollution-free, and having a high power density. The fuel cell to which the fast calculation method of this embodiment can be applied can be a proton exchange membrane fuel cell or other types of fuel cells with membrane electrodes.

[0108] The fast calculation method proposed in this embodiment corrects the initial acceleration factor by introducing a contribution factor on the basis of the change in microstructure for the durability test results of the catalyst support based on a single condition and the multi-factor decay durability test results based on the actual vehicle condition, that is, the initial acceleration factor is corrected by coupling the microstructure and performance parameters, so as to establish the correlation between the single-factor accelerated durability of the fuel cell and the multi-factor constant-speed durability of the actual vehicle condition, which is of great significance for the durability evaluation of the fuel cell membrane electrode, and also provides a new idea for the life relationship between the single-condition accelerated durability of a single material and the constant-speed durability of the actual vehicle condition, and has important guiding significance for guiding the fuel cell life prediction.

[0109] In this article, specific examples are used to elaborate on the principles and implementation modes of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation modes and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A rapid calculation method for the acceleration factor of a fuel cell membrane electrode under actual vehicle conditions, characterized in that, the rapid calculation method includes: Conduct a constant-speed durability test on a first fuel cell under actual vehicle conditions until the first performance degradation rate of the first fuel cell reaches a preset value, obtaining a first fuel cell after the test and a first operation time; Conduct a single-condition accelerated durability test on a second fuel cell until the second performance degradation rate of the second fuel cell reaches the preset value, obtaining a second fuel cell after the test and a second operation time; Measure the thicknesses of the catalyst layers of the membrane electrodes of a third fuel cell, the first fuel cell after the test, and the second fuel cell after the test respectively, obtaining a reference thickness, a first thickness, and a second thickness; Calculate the acceleration factor according to the first performance degradation rate, the first operation time, the second performance degradation rate, the second operation time, the reference thickness, the first thickness, and the second thickness; the acceleration factor is used to characterize the correlation between the single-condition accelerated durability test and the constant-speed durability test under actual vehicle conditions, and calculate the life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions; The specific calculation of the acceleration factor according to the first performance degradation rate, the first operation time, the second performance degradation rate, the second operation time, the reference thickness, the first thickness, and the second thickness includes: Calculate the first thickness degradation rate of the first fuel cell according to the reference thickness and the first thickness; calculate the second thickness degradation rate of the second fuel cell according to the reference thickness and the second thickness; Calculate the contribution factor according to the first performance degradation rate, the second performance degradation rate, the first thickness degradation rate, and the second thickness degradation rate; Calculate the acceleration factor according to the first operation time, the second operation time, and the contribution factor.

2. The rapid calculation method according to claim 1, characterized in that, The specific steps of conducting a constant-speed durability test on a first fuel cell under actual vehicle conditions until the first performance degradation rate of the first fuel cell reaches a preset value, obtaining a first fuel cell after the test and a first operation time include: Activate the first fuel cell to obtain a first fuel cell after activation; conduct a performance retest on the first fuel cell after activation to obtain a first polarization curve; Run a first condition curve on the first fuel cell after activation for several times to obtain a first fuel cell after operation; Perform reversible loss recovery on the first fuel cell after operation to obtain a first fuel cell after recovery; conduct a performance retest on the first fuel cell after recovery to obtain a second polarization curve; Determine the first performance degradation rate of the first fuel cell according to the first polarization curve and the currently obtained second polarization curve, and judge whether the first performance degradation rate reaches the preset value; If so, end the constant-speed durability test under actual vehicle conditions, use the first fuel cell after recovery as the first fuel cell after the test, and determine the total operation time of the first condition curve in the constant-speed durability test under actual vehicle conditions to obtain the first operation time; If not, continue the actual vehicle operating condition constant speed endurance test, use the first restored fuel cell as the first activated fuel cell, and return to the step of "running the first operating condition curve several times on the first activated fuel cell to obtain the first operating fuel cell".

3. The fast calculation method according to claim 2, It is characterized in that The step of performing a single-operating-condition accelerated endurance test on the second fuel cell until the second performance attenuation rate of the second fuel cell reaches the preset value, and obtaining the second fuel cell after the second test and the second operating time specifically includes: activating the second fuel cell to obtain a second activated fuel cell; retesting the performance of the second activated fuel cell to obtain a third polarization curve; Running a second operating curve several times on the second activated fuel cell to obtain a second operated fuel cell; Performing reversible loss recovery on the second operating fuel cell to obtain a second recovered fuel cell; retesting the performance of the second recovered fuel cell to obtain a fourth polarization curve; determining a second performance decay rate of the second fuel cell according to the third polarization curve and the currently obtained fourth polarization curve, and judging whether the second performance decay rate reaches the preset value; If yes, then the single-operating-condition accelerated endurance test is terminated, the second recovered fuel cell is used as the second post-test fuel cell, and the total operating time of the second operating condition curve in the single-operating-condition accelerated endurance test is determined to obtain a second operating time; If not, continue the single operating condition accelerated endurance test, use the second restored fuel cell as the second activated fuel cell, and return to the step of "running the second operating condition curve several times on the second activated fuel cell to obtain a second operating fuel cell".

4. The fast calculation method according to claim 3, It is characterized in that The test fixture and test conditions used in the single-operating-condition accelerated endurance test and the actual-vehicle-operating-condition normal-speed endurance test are the same; the activation method and activation end judgment condition used for activating the first fuel cell and the second fuel cell are the same; the performance retest of the first activated fuel cell, the performance retest of the first restored fuel cell, the performance retest of the second activated fuel cell, and the performance retest of the second restored fuel cell are the same; the reversible loss recovery of the first operating fuel cell and the reversible loss recovery of the second operating fuel cell are the same.

5. The fast calculation method according to claim 3, It is characterized in that The second operating condition curve is a triangular wave voltage curve.

6. The fast calculation method according to claim 1, It is characterized in that The method for measuring the thickness of the catalyst layer of the membrane electrode comprises: Use a three-ion beam cutting instrument to cut multiple sampling positions of the membrane electrode respectively, take cross-sectional photos corresponding to each of the sampling positions by using a scanning electron microscope, and determine the thickness of the catalyst layer at each of the sampling positions; calculate the average value of the thicknesses of the catalyst layers at all the sampling positions to obtain the thickness of the catalyst layer of the membrane electrode; the membrane electrode is the membrane electrode of the third fuel cell, the first post-test fuel cell, and the second post-test fuel cell.

7. According to the rapid calculation method described in claim 1, wherein, the calculation formula of the contribution factor is: ； Among them, is the contribution factor; c is the second performance decay rate; b is the first thickness decay rate; a is the first performance decay rate; d is the second thickness decay rate.

8. According to the rapid calculation method described in claim 1, wherein, the calculation formula of the acceleration factor is: ； Among them, is the acceleration factor; is the contribution factor; is the first running time; is the second running time.

9. According to the rapid calculation method described in claim 1, wherein, the specific steps of calculating the service life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions include: Conduct a single-condition accelerated durability test on the fuel cell to be tested to determine the service life of the membrane electrode of the fuel cell to be tested under a single condition; use the acceleration factor to correct the service life under the single condition to obtain the service life of the membrane electrode of the fuel cell to be tested under actual vehicle conditions.

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