A method for rapid activation of a fuel cell stack composed of a low platinum loading membrane electrode assembly

Abstract

The application discloses a kind of low platinum load film electrode composition's fuel cell stack quick activation method, belong to fuel cell technical field.The quick activation method includes the following steps: S01.to anode and cathode are purged;S02.sets up stack activation operating condition, anode / cathode metering ratio is 1.5-2.0 / 1.6-2.2;S03.first load to 1.1-1.2A / cm 2 ;S04.second load to 1.9-2.1A / cm 2 ;S05.according to 0.09-0.11A / cm 2 Increase 5-7 times of load successively;S06.decrease to rated electric density point maintains 4-6min, completes activation.The quick activation method of the application can effectively shorten the activation time of membrane electrode by low potential activation method, and significantly improve the polarization performance of low platinum load membrane electrode composition's fuel cell.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, and particularly relates to a rapid activation method for a fuel cell stack composed of a low platinum loading membrane electrode assembly. Background Technology

[0002] The core component of a proton exchange membrane fuel cell (PEMFC) is the membrane electrode assembly (MEA), and its performance largely determines the overall performance of the fuel cell. The materials that make up the MEA include the catalyst, and the content of elements such as platinum, rhodium, and palladium in the catalyst significantly impacts its performance. To ensure that the PEMFC quickly reaches its optimal state and performance after startup, the MEA typically undergoes activation treatment before being prepared and assembled into a fuel cell stack for normal testing and operation.

[0003] Activation is generally considered to include the following processes: (1) humidification of the proton exchange membrane; (2) establishment of mass transport channels; (3) optimization of the electrode structure; and (4) improvement of the activity and utilization rate of the catalyst layer. Activation of PEMFCs can enhance the hydration of the proton exchange membrane and improve the output performance of the fuel cell. Therefore, the choice of MEA activation method is crucial to the performance of PEMFCs. Traditional PEMFC activation processes typically require several hours or days, which not only consumes a large amount of hydrogen but also delays the PEMFC production cycle. A reasonable activation method can not only improve the performance of PEMFCs but also significantly reduce activation time and gaseous fuel consumption, thereby substantially reducing activation costs.

[0004] Currently, the platinum loading at the cathode of a conventional membrane electrode is 0.4 ± 0.05 mg / cm². 2 When the platinum loading reaches 0.3 mg / cm³ 2 The following are examples of low platinum loading. Reducing the Pt / C ratio reduces material costs to some extent and is a future development trend.

[0005] However, rapid activation is a challenge for cell stacks composed of membrane electrodes with low platinum loading. Existing activation procedures require more than 3 hours or even several days to allow the membrane electrodes to reach their optimal performance, which consumes a lot of manpower and materials (hydrogen). As a result, the cost savings from reducing platinum loading are then reinvested in the activation process, which defeats the original purpose of cost reduction. Summary of the Invention

[0006] The purpose of this invention is to provide a rapid activation method for fuel cell stacks composed of low platinum loading membrane electrode assemblies, aiming to solve the problems of long activation time, high manpower and hydrogen material consumption, and low activation efficiency of existing fuel cell stacks composed of low platinum loading membrane electrode assemblies.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly specifically includes the following steps:

[0009] S01. The anode and cathode of the fuel cell stack composed of low platinum loading membrane electrodes are purged;

[0010] S02. Set the fuel cell stack activation operation conditions: fuel cell stack temperature is 60-100℃, anode / cathode pressure is 100-190 / 80-170kPa, anode / cathode humidity is 30-100 / 30-100%, and anode / cathode metering ratio is 1.5-2.0 / 1.6-2.2;

[0011] S03. Apply a single load to 1.1-1.2 A / cm. 2 Maintain for 4-6 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.05-1.08, maintain for 18-22 seconds, and restore the flow rate for 50 seconds to 1 minute.

[0012] S04. Secondary load increased to 1.9-2.1 A / cm 2 Maintain for 4-6 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10-1.3 and maintain for 18-22 seconds, then restore the flow rate and maintain for 50 seconds to 1 minute.

[0013] S05. According to 0.09-0.11A / cm 2 The flow rate is increased gradually in 5-7 cycles. After each cycle, the flow rate is maintained for 4-6 minutes, keeping the anode metering ratio constant. The cathode metering ratio is then reduced to 1.10-1.3 and maintained for 18-22 seconds. The flow rate is then restored and maintained for 50 seconds to 1 minute.

[0014] S06. Reduce the voltage to the rated electrical density point and maintain for 4-6 minutes to complete the activation.

[0015] Preferably, in step S01:

[0016] The low platinum loading refers to a platinum loading of 0.3 mg / cm³. 2 the following.

[0017] The gas used for purging is nitrogen;

[0018] The purging process specifically involves purging with nitrogen gas for 2-4 minutes.

[0019] A further preferred method is to wash away the contaminants with water before purging.

[0020] Preferably, in step S02:

[0021] The activated operation conditions for the fuel cell stack are as follows: stack temperature 60℃, anode / cathode pressure 190 / 170kPa, anode / cathode humidity 100 / 100%, and anode / cathode metering ratio 1.7 / 2.2.

[0022] Preferably, in step S03:

[0023] Specifically: a single load of 1.2 A / cm 2 Maintain for 5 minutes, keep the anode metering ratio unchanged, reduce the cathode metering ratio to 1.08, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0024] Preferably, in step S04:

[0025] Specifically: Secondary load increased to 2.0 A / cm 2 Maintain for 5 minutes, keep the anode metering ratio unchanged, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0026] Preferably, in step S05:

[0027] Specifically: according to 0.1A / cm 2 The flow rate was increased in six stages, and after each stage, it was maintained for 5 minutes while keeping the anode metering ratio constant. The cathode metering ratio was then reduced to 1.10 and maintained for 20 seconds. Finally, the flow rate was restored and maintained for 1 minute.

[0028] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0029] The rapid activation method described in this patent application is used in fuel cells with low platinum loading membrane electrode assemblies. This is achieved through a significant change in current density between the first and second loading cycles, and a small change in current density (0.09-0.11 A / cm²) over 5-7 cycles after the second loading cycle. 2 By increasing the amount of platinum loading (while keeping the anode stoichiometric ratio constant and gradually decreasing the cathode stoichiometric ratio to a fixed value (1.10-1.3), rapid activation of fuel cells with low platinum loading membrane electrodes can be achieved within 48-50 minutes. This method is suitable for platinum loadings up to 0.3 mg / cm³. 2 The following fuel cell with low platinum loading membrane electrode assembly can effectively shorten the membrane electrode activation time and significantly improve the polarization performance of the fuel cell with low platinum loading membrane electrode assembly by using a low-potential activation method. Attached Figure Description

[0030] Figure 1 This is a low-potential activation flowchart provided in Embodiment 1 of the present invention. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Furthermore, if the embodiments of this invention involve descriptions such as "first time" or "second time," these descriptions are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first time" or "second time" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0033] Currently, existing fuel cell stacks composed of membrane electrode assemblies with low platinum loading suffer from problems such as long activation time, high manpower and hydrogen material consumption, and low activation efficiency. This invention provides a rapid activation method for fuel cell stacks composed of membrane electrode assemblies with low platinum loading.

[0034] Example 1

[0035] A rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly specifically includes the following steps:

[0036] S01. Purge the anode and cathode of the fuel cell stack composed of low platinum loading membrane electrodes with nitrogen gas for 3 minutes;

[0037] S02. Set the fuel cell stack activation operating conditions: fuel cell stack temperature 60℃, anode / cathode pressure 190 / 170kPa, anode / cathode humidity 100 / 100%, anode / cathode metering ratio 1.7 / 2.2;

[0038] S03. Load 1.2A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.08 and maintain for 20 seconds, then restore the flow rate and maintain for 1 minute;

[0039] S04. Load 2.0A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0040] S05. Load 2.1A / cm 2Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0041] S06. Load 2.2A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0042] S07. Load 2.3A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0043] S08. Load 2.4A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0044] S09. Load 2.5A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0045] S10. Load 2.6A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0046] S11. Reduce the voltage to the rated electrical density point and maintain for 5 minutes to complete the activation.

[0047] The low-potential activation flowchart of the rapid activation method in Example 1 is shown below. Figure 1 As shown, activation was performed at a lower potential, and the total activation time was 48 minutes, which is much shorter than the existing activation time for fuel cell stacks composed of low platinum loading membrane electrodes.

[0048] Example 2

[0049] A rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly specifically includes the following steps:

[0050] S01. Purge the anode and cathode of the fuel cell stack composed of low platinum loading membrane electrodes with nitrogen gas for 4 minutes;

[0051] S02. Set the fuel cell stack activation operating conditions: fuel cell stack temperature 100℃, anode / cathode pressure 100 / 80kPa, anode / cathode humidity 30 / 30%, anode / cathode metering ratio 1.7 / 2.2;

[0052] S03. Load 1.1A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.05 and maintain for 22 seconds, then restore the flow rate and maintain for 50 minutes;

[0053] S04. Load 1.9A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0054] S05. Load 2.0A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0055] S06. Load 2.1A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0056] S07. Load 2.2A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0057] S08. Load 2.3A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0058] S09. Load 2.4A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0059] S10. Load 2.5A / cm 2 Maintain for 5 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

[0060] S11. Reduce the voltage to the rated electrical density point and maintain for 5 minutes to complete activation. The total activation time is 50 minutes, which is much shorter than the existing activation time for fuel cell stacks composed of low platinum loading membrane electrodes.

[0061] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0062] The rapid activation method described in this patent application is used in fuel cells with low platinum loading membrane electrode assemblies. This is achieved through a significant change in current density between the first and second loading cycles, and a small change in current density (0.09-0.11 A / cm²) over 5-7 cycles after the second loading cycle. 2 By increasing the amount of platinum loading (while keeping the anode stoichiometric ratio constant and gradually decreasing the cathode stoichiometric ratio to a fixed value (1.10-1.3), rapid activation of fuel cells with low platinum loading membrane electrodes can be achieved within 48-50 minutes. This method is suitable for platinum loadings up to 0.3 mg / cm³. 2 The following fuel cell with low platinum loading membrane electrode assembly can effectively shorten the membrane electrode activation time and significantly improve the polarization performance of the fuel cell with low platinum loading membrane electrode assembly by using a low-potential activation method.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly, characterized in that: Specifically, the following steps are included: S01. The anode and cathode of the fuel cell stack composed of low platinum loading membrane electrodes are purged; S02. Set the fuel cell stack activation operation conditions: fuel cell stack temperature is 60-100℃, anode / cathode pressure is 100-190 / 80-170kPa, anode / cathode humidity is 30-100 / 30-100%, and anode / cathode metering ratio is 1.5-2.0 / 1.6-2.2; S03. Apply a single load to 1.1-1.2 A / cm. 2 Maintain for 4-6 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.05-1.08, maintain for 18-22 seconds, and restore the flow rate for 50 seconds to 1 minute. S04. Secondary load increased to 1.9-2.1 A / cm 2 Maintain for 4-6 minutes, keep the anode metering ratio constant, reduce the cathode metering ratio to 1.10-1.3 and maintain for 18-22 seconds, then restore the flow rate and maintain for 50 seconds to 1 minute. S05. According to 0.09-0.11A / cm 2 The flow rate is increased gradually in 5-7 cycles. After each cycle, the flow rate is maintained for 4-6 minutes, keeping the anode metering ratio constant. The cathode metering ratio is then reduced to 1.10-1.3 and maintained for 18-22 seconds. The flow rate is then restored and maintained for 50 seconds to 1 minute. S06. Reduce the voltage to the rated electrical density point and maintain for 4-6 minutes to complete the activation.

2. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: In step S01: the low platinum loading is a platinum loading of 0.3 mg / cm³. 2 the following.

3. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: In step S01: the gas used for purging is nitrogen.

4. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: The purging process specifically involves purging with nitrogen gas for 2-4 minutes.

5. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: In step S02: the activated operation conditions of the fuel cell stack are: stack temperature 60°C, anode / cathode pressure 190 / 170 kPa, anode / cathode humidity 100 / 100%, and anode / cathode metering ratio 1.7 / 2.

2.

6. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: In step S03: Specifically, the load is applied once to 1.2 A / cm. 2 Maintain for 5 minutes, keep the anode metering ratio unchanged, reduce the cathode metering ratio to 1.08, maintain for 20 seconds, and restore the flow rate for 1 minute.

7. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: In step S04: Specifically, a second load is applied to 2.0 A / cm. 2 Maintain for 5 minutes, keep the anode metering ratio unchanged, reduce the cathode metering ratio to 1.10, maintain for 20 seconds, and restore the flow rate for 1 minute.

8. The rapid activation method for a fuel cell stack composed of a low-platinum-loading membrane electrode assembly according to claim 1, characterized in that: In step S05: specifically, according to 0.1A / cm 2 The flow rate was increased in six stages, and after each stage, it was maintained for 5 minutes while keeping the anode metering ratio constant. The cathode metering ratio was then reduced to 1.10 and maintained for 20 seconds. Finally, the flow rate was restored and maintained for 1 minute.

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