Durability test method, system and device for fuel cell stack

Abstract

The invention discloses a durability test method, system and device for a fuel cell stack, and the method comprises the steps: (1) verifying a durability working condition: carrying out the constant-current operation for 1 hour under a selected current point through employing the durability working condition, and verifying whether the durability setting condition is reasonable or not; (2) determining the cycle working condition of the electric pile, and performing cycle intermittent shutdown: performing intermittent shutdown once every 10-20 cycles, wherein the shutdown time is 1-2 hours; (3) regular performance test: carrying out polarization test on the fuel cell stack every 100 hours; carrying out an activation test on the fuel cell stack every 200h; (4) judging the termination condition of the durability test: stopping the test when the average voltage attenuation under 2A / cm < 2 > exceeds 10%; or the test is stopped when the minimum monomer voltage under any current density is lower than 0.4 V.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a durability testing method, system and device for a fuel cell stack. Background Art

[0002] With the continuous development of fuel cell technology, its application prospects in many fields are becoming increasingly broad. However, the durability of fuel cell stacks has always been one of the key bottlenecks hindering their large-scale commercial promotion. In actual application scenarios, fuel cell stacks need to operate stably under long-term, complex and changeable working conditions. For example, in the automotive field, fuel cell vehicles may face frequent starts and stops, load changes at different driving speeds, and various environmental conditions (temperature, humidity, air pressure, etc.); in distributed power generation systems, stacks also need to cope with different fluctuations in electricity demand and the test brought by long-term continuous operation.

[0003] Existing fuel cell stack durability test methods have many shortcomings. The operating condition simulation of some test methods is not comprehensive and accurate enough. They often simply test at a limited number of current density points or operating modes, and cannot truly reflect the performance changes of the stack in the actual complex operating environment. In addition, the conditions during the durability test are not reasonable enough, and the attenuation of the membrane electrode is often not caused by itself but by unreasonable external conditions.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a durability testing method, system and device for a fuel cell stack.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a method, system and device for durability testing of a fuel cell stack.

[0007] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0008] Durability test methods for fuel cell stacks, including

[0009] (1) Durable working condition verification: Run the machine at a constant current for 1 hour under the selected current point to verify whether the durable setting conditions are reasonable;

[0010] (2) Determine the cycle conditions and intermittent shutdown of the battery stack: perform an intermittent shutdown every 10-20 cycles, with a shutdown time of 1-2 hours;

[0011] (3) Regular performance test: polarization test of fuel cell stack every 100 hours; activation test of fuel cell stack every 200 hours;

[0012] (4) Durability test termination condition judgment: at 2A / cm 2 The test is stopped when the average voltage decay under any current density exceeds 10%; or the test is stopped when the lowest single cell voltage under any current density is lower than 0.4V.

[0013] In one or more embodiments of the present invention, the cycle condition in step (2) is: quickly pull the load to 0.3A / cm 2 Slightly over-potential; pull to 0.7-0.9A / cm 2 And keep it for 20min; pull the load to 1.2-1.4A / cm 2 And keep it for 20 minutes; pull the load to 1.7-1.8A / cm 2 And keep it for 20min; pull the load to 2.0A / cm 2 And keep it for 20min; reduce the load to 0.2A / cm 2 And keep it for 5 minutes; reduce the load to 0.02A / cm 2 Discharge with a small current; finally stop and keep for 10 minutes.

[0014] In one or more embodiments of the present invention, the durability operating conditions in step (1) are selected from: anode gas flow, cathode gas flow, anode stack pressure, cathode stack pressure, cathode inlet temperature, anode inlet temperature, cathode dew point temperature, anode dew point temperature, circulating water stack temperature and circulating water flow.

[0015] In one or more embodiments of the present invention, the endurance condition in step (1) is: 0.7-0.9A / cm 2 , 1.2-1.4A / cm 2 , 1.7-1.8A / cm 2 and 2.0A / cm 2 Corresponding to the current, each current density point corresponds to the working condition and operates at constant current for 1 h.

[0016] In one or more embodiments of the present invention, step (1) also includes an activation test before constant current operation under endurance conditions: the anode inlet pressure is 160 kPa, the cathode inlet pressure is 150 kPa, the anode gas stoichiometric ratio is 1.5, the cathode gas stoichiometric ratio is 2.0, the anode and cathode inlet temperatures are 75°C, the anode and cathode dew point temperatures are 69°C, and the circulating water inlet temperature is 75±5°C.

[0017] In one or more embodiments of the present invention, step (1) also includes a polarization test before constant current operation under endurance conditions. The polarization test should be performed after the activation test is completed. The test current density range is 0-2A / cm 2 , designed to perform initial performance calibration of the fuel cell stack.

[0018] In one or more embodiments of the present invention, the polarization test conditions in step (3) must be consistent with the polarization curve test conditions in the initial state in step (1), that is, in the current density range of 0-2A / cm 2 Carry out in the interval.

[0019] In one or more embodiments of the present invention, the activation test in step (3) adopts the basic principle of high humidity and low back pressure, specifically, the cathode and anode air inlet temperature is 75°C, the cathode and anode dew point temperature is 69°C, the circulating water inlet temperature is 75±5°C, the anode air inlet pressure is 60-100 kPa, the cathode air inlet pressure is 50-90 kPa, and it is necessary to ensure that the anode air inlet pressure is greater than the cathode air inlet pressure, at 2A / cm 2 The average cell voltage of the stack was controlled below 0.6 V and operated at constant current for 1 hour.

[0020] In one or more embodiments of the present invention, a test system includes a control system for running a computer program to perform a durability test method for a fuel cell stack.

[0021] In one or more embodiments of the present invention, a testing device includes a memory and a processor; the memory is used to store a computer program; the processor is used to implement a durability testing method for a fuel cell stack when executing the computer program.

[0022] Compared with the prior art, the fuel cell stack durability test method, system and device of the present invention have the following advantages:

[0023] (1) Setting up the durability condition verification link can avoid the adverse effects of unreasonable durability conditions on the membrane electrode. In the durability cycle condition, the corresponding platform of each current density point is often only 10-20 minutes, and the rationality of the durability conditions cannot be verified in such a short time. Therefore, setting up the durability condition verification link before the start of the durability cycle can eliminate the influence of conditions on the membrane electrode attenuation during the durability cycle, which is more conducive to the subsequent membrane electrode verification and performance attenuation analysis.

[0024] (2) Comprehensive stack cycle operating condition design: Through multi-stage loading, holding and load reduction operations with different electrical densities, as well as specific shutdown and low-current discharge steps, the various operating conditions that the fuel cell stack may encounter in actual operation are fully simulated. This can more comprehensively test the performance stability and durability of the stack under different working conditions, avoiding the limitations of the traditional test method with a single operating condition.

[0025] (3) Reasonable cyclic intermittent shutdown settings and reasonable operating conditions: Simulating intermittent working conditions in actual use makes the test results closer to the actual application scenarios, and can more accurately evaluate the durability performance of the fuel cell stack in long-term actual operation. It also helps the performance recovery mechanism of the fuel cell stack during the intermittent process.

[0026] (4) Regular performance testing and termination condition judgment: Regular polarization curve testing and activation testing can timely and accurately capture subtle changes in stack performance, especially changes in catalyst activity, providing a powerful means for early warning of stack performance degradation and fault diagnosis. Clear endurance test termination conditions not only ensure the adequacy of the test, but also prevent waste of resources and uncertainty in test results caused by excessive testing, thereby improving test efficiency and reliability of results. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A durability test flow chart of a durability test method for a fuel cell stack in one embodiment of the present invention;

[0029] Figure 2 This is a durability condition verification diagram of a durability test method for a fuel cell stack in one embodiment of the present invention;

[0030] Figure 3 This is a durability cycle operating condition diagram of a durability testing method for a fuel cell stack in one embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] The purpose of the present invention is to provide a fuel cell stack durability test method, comprising the following steps:

[0033] (1) Durability test verification: Run the machine at a constant current for 1 hour under the selected current density point to verify whether the durability setting conditions are reasonable;

[0034] (2) Stack cycle condition: Rapid loading to 0.3A / cm 2 Slightly over-potential; pull to 0.7-0.9A / cm 2 And keep it for 20min; pull the load to 1.2-1.4A / cm 2 And keep it for 20 minutes; pull the load to 1.7-1.8A / cm 2 And keep it for 20min; pull the load to 2.0A / cm 2 And keep it for 20min; reduce the load to 0.2A / cm 2 And keep it for 5 minutes; reduce the load to 0.02A / cm 2 Discharge with a small current; finally stop and keep for 10 minutes;

[0035] (3) Cycle intermittent shutdown: every 10-20 cycles, an intermittent shutdown is performed, and the shutdown time is 1-2 hours;

[0036] (4) Regular performance test: Perform a polarization curve test on the fuel cell stack every 100 hours; perform an activation test on the fuel cell stack every 200 hours;

[0037] (5) Durability test termination condition judgment: at 2A / cm 2 The test is stopped when the average voltage decay exceeds 10%; the test is stopped when the lowest single cell voltage at any current density point is lower than 0.4V.

[0038] In one embodiment of the present invention, in step (1), the stack needs to undergo activation test and polarization test. The activation test time is not less than 4 hours. The activation judgment standard is that the average voltage fluctuation at the same current density point is within ±2mV. The polarization test needs to be carried out according to the membrane electrode supplier or the verified working conditions, and the polarization curve is drawn as the initial performance calibration curve. The selected current density point is 0.7-0.9A / cm 2, 1.2-1.4A / cm 2 , 1.7-1.8A / cm 2 and 2.0A / cm 2 Corresponding current; if the endurance condition is stable during the 1h constant current operation, the average voltage fluctuates within ±1mV, which is considered to be a reasonable setting of the endurance condition. Otherwise, the endurance condition setting is unreasonable and needs to be adjusted.

[0039] In one embodiment of the present invention, in step (2), the loading process should pre-set the working conditions corresponding to the target current density point, including the anode and cathode gas flow rate, the anode and cathode inlet pressure, the anode and cathode inlet gas temperature, the anode and cathode dew point temperature, the circulating water inlet temperature and the circulating water flow rate, etc. After the conditions are stable, the loading is carried out, and the loading rate should be between 0.1A / cm per second. 2 Corresponding current and 0.2A / cm 2 In the corresponding current range, if the membrane electrode active area is 300cm 2 , the loading rate should be between 30-60A / s, which can not only achieve the rapid reduction of the cathode high potential, but also ensure that the loading rate will not be too fast to cause partial gas shortage inside the membrane electrode; the load reduction process should first reduce the current, and then modify the condition to 0.2A / cm after the current stabilizes. 2 Under the corresponding working conditions, the load reduction rate should not exceed 0.2A / cm 2 Corresponding current per second; load reduction to 0.02A / cm 2 Perform low current discharge. At this time, the current should be reduced first. After the current stabilizes, switch the cathode side gas to dry nitrogen and maintain 0.1A / cm 2 Corresponding to the cathode gas flow, the other conditions remain unchanged. When the minimum cell voltage is monitored to be less than 0.15V, the stack current is reduced to 0A; shutdown includes shutting down the electronic load, cathode and cathode gas flow, cathode and cathode inlet pressure, cathode and cathode inlet temperature, cathode and cathode inlet dew point temperature, circulating water inlet temperature and circulating water flow.

[0040] In one embodiment of the present invention, in step (3), if an unexpected shutdown occurs during 10-20 cycles of operation, after eliminating factors related to the battery stack itself, the 10-20 endurance cycles should be recounted.

[0041] In one embodiment of the present invention, in step (4), the polarization test conditions must be consistent with the initial polarization test conditions, and a polarization curve is drawn; the activation test adopts a high humidity and low back pressure activation method, the purpose of which is to create a high humidity and low potential cathode reduction environment for the membrane electrode.

[0042] In one embodiment of the present invention, in step (5), at 2A / cm 2The test is stopped when the average voltage decay exceeds 10% under the cycle condition of 2A / cm 2 Average voltage and polarization curve test at 2A / cm 2 One or more of the average voltages under the conditions; stopping the test when the lowest single cell voltage at any current density point is lower than 0.4V refers to one or more of any current density points in the cycle condition and any current density points in the polarization curve test.

[0043] Example 1

[0044] The durability test process in this embodiment is as follows Figure 1 As shown in the figure, a short stack of 20 fuel cells was selected for the test, and the membrane electrode active area was 300cm 2 Before the test begins, the short stack is first subjected to air tightness test, activation test and polarization test. The air tightness test conditions and judgment criteria are shown in Table 1, and the test gas is nitrogen. The short stack activation test adopts a variable load activation test, setting the anode inlet pressure to 160kPa, the cathode inlet pressure to 150kPa, the anode gas stoichiometric ratio to 1.5, the cathode gas stoichiometric ratio to 2.0, the cathode and cathode inlet temperature to 75℃, the cathode and cathode dew point temperature to 69℃, the circulating water inlet temperature to 75℃, and the temperature difference to no more than 5℃. When the average voltage fluctuation at the same current density point is within the range of ±2mV, it can be judged that the activation is completed and the polarization curve test is carried out. The polarization test conditions are shown in Table 2.

[0045] After the polarization curve calibration is completed, the durability condition verification is first performed, and 0.7A / cm 2 , 1.2A / cm 2 , 1.7A / cm 2 and 2.0A / cm 2 The corresponding current and the corresponding working conditions of each current density point are shown in Table 3. At the four current density points, the conditions in Table 3 were selected to run at constant current for 1 hour. The results are as follows Figure 2 As shown, 0.7A / cm 2 The average voltage under the condition is within 0.762±1mV; 1.2A / cm 2 The average voltage under the condition is within 0.721±1mV; 1.7A / cm 2 The average voltage under the condition is within 0.672±1mV; 2.0A / cm 2 The average voltage under the four current density points is within 0.647±1mV; it can be seen that the average voltage fluctuations at the four current density points are all controlled within ±1mV, which determines that the durability conditions are set reasonably and durability cycle verification can be carried out.

[0046] Durable cycle conditions such as Figure 3 As shown in the figure, the load rate is set to 30A / s, and the current is quickly pulled to 0.3A / cm after the stack is started.2 That is, 90A, which not only achieves a quick pass over the cathode high potential, but also avoids the risk of partial gas deficiency inside the membrane electrode due to excessive loading speed. Maintain 90A current and set 0.7A / cm 2 That is, the corresponding condition of 210A, after the condition is stable, the current is increased at a rate of 5A / s to pull the short stack to 210A and stabilize for 20 minutes. The relative humidity of the anode and cathode inlet air set at 210A is 50%, which ensures that when the membrane electrode itself produces less water under low electric density, the proton exchange membrane still has sufficient water for proton transmission, avoiding performance degradation caused by the drying of the proton exchange membrane. Maintain 210A current and set 1.2A / cm 2 That is, 360A corresponds to the condition. After the condition is stable, the current is increased at a rate of 5A / s to load the short stack to 360A and stabilize for 20 minutes. Maintain 360A current and set 1.7A / cm 2 That is, the corresponding conditions of 510A, after the conditions are stable, the current is increased at a rate of 5A / s to pull the short stack to 510A and stabilize for 20 minutes. The water inlet temperature at 510A is set to 70°C, and the relative humidity of the anode and cathode inlet air is 30%. This is because the membrane electrode itself produces a lot of water at 510A. At this time, the risk of flooding should be avoided. The rapid discharge of water inside the stack can be achieved by reducing the relative humidity of the inlet air and increasing the water inlet temperature. Maintain 510A current and set 2.0A / cm 2 That is, the corresponding condition of 600A, after the condition is stable, the current is increased at a rate of 5A / s to load the short stack to 600A and stabilized for 20 minutes. At 600A, the water inlet temperature is further increased and the relative humidity of the inlet air is reduced, which is also conducive to the rapid discharge of generated water under high current density, avoiding abnormal degradation of membrane electrode performance due to operating conditions during the endurance test. Maintain the corresponding condition of 600A current and reduce the short stack to 0.2A / cm at a rate of 20A / s. 2 That is, 60A. After the current stabilizes, the conditions are modified to the working conditions corresponding to 60A and stabilized for 5 minutes. 60A is the preparation stage before shutdown. Under this current, the single cell voltage does not exceed 0.85V. It can be used as a stable stage before low-current discharge. After the conditions stabilize, low-current discharge operation is performed. Maintain the corresponding conditions of 60A current and reduce the load of the short stack to 0.02A / cm at a load reduction rate of 20A / s. 2That is, 6A. After the current stabilizes, switch the cathode side gas to dry nitrogen and maintain a current of 60A corresponding to the cathode gas flow rate, and the other conditions remain unchanged. At this time, the cathode gas is dry nitrogen, and the anode gas is humidified hydrogen. During the small current discharge process, a hydrogen pump effect is generated, which causes some hydrogen to be produced on the cathode side to create a reducing environment. Combined with the low potential on the cathode side at this time, the surface oxides of the cathode side catalyst are quickly removed, greatly improving the service life of the membrane electrode. When the minimum single cell voltage is monitored to be less than 0.15V, the stack current is reduced to 0A, and finally shut down and maintained for 10 minutes. At this time, the first endurance cycle ends and the next endurance cycle begins. After 10 endurance cycles, the shutdown step of 1h is entered. During the shutdown process, the performance recovery mechanism of the stack in the intermittent process is helpful, involving processes such as water redistribution inside the membrane electrode, releasing more active sites.

[0047] When the endurance cycle test is completed for 100h, the stack is polarized. The polarization test conditions must be consistent with the polarization curve test conditions in the initial state, as shown in Table 2. Observe and analyze the average voltage decay at the same current density point. If it appears at 2A / cm 2 When the performance degradation under the condition exceeds 10% or the average voltage at any current density point is lower than 0.4V, the endurance test is stopped. Otherwise, the endurance cycle test is continued after the polarization curve test is completed. When the endurance cycle test is completed for 200h, the stack is activated. The activation adopts the basic principle of high humidity and low back pressure. Specifically, the anode and cathode inlet temperature is 75℃, the anode and cathode dew point temperature is 69℃, the circulating water inlet temperature is 75℃, the anode inlet pressure is 80kPa, the cathode inlet pressure is 70kPa, and the activation temperature is 2A / cm 2 The average cell voltage of the stack was controlled below 0.6V and operated at a constant current for 1 hour. The purpose of the high humidity and low back pressure activation method is to create a high humidity and low potential reduction environment for the cathode, which helps to remove the platinum oxide on the surface of the cathode catalyst Pt and increase the active sites. At the same time, high humidity can wet the proton exchange membrane and reduce the proton conduction resistance. After the activation is completed, the polarization curve test is carried out, and after the polarization curve test is completed, the endurance cycle test continues.

[0048] Follow all the above procedures to test until 2A / cm in the cycle condition 2 Average voltage and polarization curve test at 2A / cm 2 The endurance test is stopped when one or more of the average voltages under the test conditions decays by more than 10%, or when the average cell voltage at any current density point in the cycle condition and at any current density point in the polarization curve test is lower than 0.4V.

[0049] Table 1 Air tightness test conditions and judgment criteria

[0050] Test items Test gas pressure Criteria Hydrogen Field 50kPa <![CDATA[≤0.003mL / cm 2 / min]]> Empty 50kPa <![CDATA[≤0.003mL / cm 2 / min]]> Water field 50kPa 0 Hydrogen, air and water 200kPa 0

[0051] Table 2 Polarization test conditions

[0052]

[0053] Table 3 Durability cycle working conditions

[0054]

[0055] Example 2

[0056] The difference between this embodiment and embodiment 1 is that the fuel cell stack is activated every 200 hours under the following conditions: the inlet air temperature of the cathode and anode is 75°C, the dew point temperature of the cathode and anode is 69°C, the circulating water inlet temperature is 80°C, the anode inlet pressure is 100 kPa, the cathode inlet pressure is 90 kPa, and the activation test is performed on the fuel cell stack every 200 hours. 2 The average cell voltage of the stack was controlled below 0.6 V and operated at constant current for 1 hour.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that when the fuel cell stack is activated every 200 hours, the conditions are: the inlet air temperature of the cathode and the anode is 75°C, the dew point temperature of the cathode and the anode is 69°C, the circulating water inlet temperature is 70°C, the anode inlet pressure is 60kPa, the cathode inlet pressure is 50kPa, and the activation test is performed on the fuel cell stack at 2A / cm 2 The average cell voltage of the stack was controlled below 0.6 V and operated at constant current for 1 hour.

[0059] Example 4

[0060] The difference between this embodiment and embodiment 1 is that an intermittent shutdown is performed every 15 cycles, and the shutdown time is 1.5 hours.

[0061] Example 5

[0062] The difference between this embodiment and embodiment 1 is that an intermittent shutdown is performed every 20 cycles, and the shutdown time is 2 hours.

[0063] Example 6

[0064] The difference between this embodiment and embodiment 1 is only that:

[0065] Durability condition verification, select 0.8A / cm 2 , 1.3A / cm 2 , 1.75A / cm 2 and 2.0A / cm 2 The constant current was operated for 1 h under the corresponding current conditions.

[0066] Cyclic working condition: Rapid pull to 0.3A / cm 2 Slightly higher potential; pull to 0.8A / cm 2 And maintain for 20 minutes; pull the load to 1.3A / cm 2 And keep it for 20 minutes; pull the load to 1.75A / cm 2 And keep it for 20min; pull the load to 2.0A / cm 2 And keep it for 20min; reduce the load to 0.2A / cm 2 And keep it for 5 minutes; reduce the load to 0.02A / cm 2 Discharge with a small current; finally stop and keep for 10 minutes.

[0067] Example 7

[0068] The difference between this embodiment and embodiment 1 is that: the endurance condition verification is performed by selecting 0.9A / cm 2 , 1.4A / cm 2 , 1.8A / cm 2 and 2.0A / cm 2 The constant current was operated for 1 h under the corresponding current conditions.

[0069] Cyclic working condition: Rapid pull to 0.3A / cm 2 Slightly higher potential; pull to 0.9A / cm 2 And maintain for 20 minutes; pull the load to 1.4A / cm 2 And keep it for 20 minutes; pull the load to 1.8A / cm 2 And keep it for 20min; pull the load to 2.0A / cm 2 And keep it for 20min; reduce the load to 0.2A / cm 2 And keep it for 5 minutes; reduce the load to 0.02A / cm 2 Discharge with a small current; finally stop and keep for 10 minutes.

[0070] The scheme of the present invention first sets reasonable cycle conditions, and through multi-stage loading, holding and load reduction operations with different current densities, as well as specific shutdown and low-current discharge steps, it can more comprehensively test the performance stability and durability of the battery stack under different working conditions, avoiding the limitation of the single working condition of the traditional test method. Then, reasonable cycle intermittent shutdown settings are used to simulate the intermittent working conditions in actual use. Finally, regular performance testing and termination condition judgment are carried out, which can timely and accurately capture the subtle changes in the performance of the battery stack, and provide a powerful means for early warning and fault diagnosis of battery stack performance degradation.

[0071] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0072] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A durability test method for a fuel cell stack, comprising: (1) Durable working condition verification: Run the machine at a constant current for 1 hour under the selected current point to verify whether the durable setting conditions are reasonable; (2) Determine the cycle conditions and intermittent shutdown of the battery stack: perform an intermittent shutdown every 10-20 cycles, with a shutdown time of 1-2 hours; (3) Regular performance test: polarization test of fuel cell stack every 100 hours; activation test of fuel cell stack every 200 hours; (4) Durability test termination condition judgment: at 2A / cm 2 The test is stopped when the average voltage decay under any current density exceeds 10%; or the test is stopped when the lowest single cell voltage under any current density is lower than 0.4V.

2. The fuel cell stack durability test method according to claim 1, characterized in that: The cycle conditions in step (2) are: rapid loading to 0.3A / cm 2 Slightly over-potential; pull to 0.7-0.9A / cm 2 And keep it for 20min; pull the load to 1.2-1.4A / cm 2 And keep it for 20 minutes; Pull load to 1.7-1.8A / cm 2 And keep it for 20min; pull the load to 2.0A / cm 2 And keep it for 20min; reduce the load to 0.2A / cm 2 And keep it for 5 minutes; reduce the load to 0.02A / cm 2 Discharge with a small current; finally stop and keep for 10 minutes.

3. The fuel cell stack durability test method according to claim 1, characterized in that: The durable operating conditions in step (1) are selected from: anode gas flow, cathode gas flow, anode stack pressure, cathode stack pressure, cathode air inlet temperature, anode air inlet temperature, cathode dew point temperature, anode dew point temperature, circulating water stack temperature and circulating water flow.

4. The fuel cell stack durability test method according to claim 3, characterized in that: The durability working condition in step (1) is: select 0.7-0.9A / cm 2 , 1.2-1.4A / cm 2 , 1.7-1.8A / cm 2 and 2.0A / cm 2 Corresponding to the current, each current density point corresponds to the working condition and operates at constant current for 1h.

5. The fuel cell stack durability test method according to claim 1, characterized in that: In step (1), an activation test is also included before constant current operation under endurance working conditions: the anode inlet pressure is 160 kPa, the cathode inlet pressure is 150 kPa, the anode gas stoichiometric ratio is 1.5, the cathode gas stoichiometric ratio is 2.0, the anode and cathode inlet temperatures are 75°C, the anode and cathode dew point temperatures are 69°C, and the circulating water inlet temperature is 75±5°C.

6. The fuel cell stack durability test method according to claim 5, characterized in that: Step (1) also includes a polarization test before constant current operation under endurance conditions, wherein the polarization test is: 2 Carry out in the interval.

7. The fuel cell stack durability test method according to claim 1, characterized in that: The polarization test in step (3) is as follows: 2 Carry out in the range.

8. The fuel cell stack durability test method according to claim 1, characterized in that: Step (3) of the activation test: the inlet air temperature of the cathode and anode is 75°C, the dew point temperature of the cathode and anode is 69°C, the circulating water inlet temperature is 75±5°C, the anode inlet pressure is 60-100 kPa, the cathode inlet pressure is 50-90 kPa, and the anode inlet pressure must be greater than the cathode inlet pressure, at 2A / cm 2 The average cell voltage of the stack was controlled below 0.6 V and operated at constant current for 1 hour.

9. A test system, comprising a control system for running a computer program to execute the durability test method for a fuel cell stack according to any one of claims 1 to 8.

10. A testing device, characterized in that It comprises a memory and a processor; the memory is used to store a computer program; the processor is used to implement the durability test method of a fuel cell stack as claimed in any one of claims 1 to 8 when executing the computer program.

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