A method for activating a proton exchange membrane fuel cell

Abstract

The present invention discloses an activation method for a proton exchange membrane fuel cell, belonging to the technical field of fuel cells, which includes the following steps: (1) purging with nitrogen; (2) heating up, introducing hydrogen into the hydrogen chamber of the proton exchange membrane fuel cell stack, introducing air into the cavity, and keeping it in an open circuit state; (3) performing constant current discharge; applying a constant current to the proton exchange membrane fuel cell stack, introducing hydrogen into the hydrogen chamber of the proton exchange membrane fuel cell stack, introducing nitrogen into the cavity, and keeping it for 1 to 15 minutes; then switching nitrogen to air and keeping it for 1 to 5 minutes; (4) repeating the operation in step (3) for 1 to 5 times; (5) performing constant current discharge again; The activation method of the present invention is simple, efficient, and short in time, and can effectively improve the discharge performance.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly relates to an activation method for a proton exchange membrane fuel cell. Background Art

[0002] A proton exchange membrane fuel cell (PEMFC) is a power generation device that directly converts chemical energy into electrical energy through an electrochemical reaction between hydrogen and oxygen, and has broad market prospects in the fields of transportation, electronic products, national defense and military, and stationary power stations. The discharge performance of a PEMFC stack mainly depends on the performance of the membrane electrode assembly (MEA). In order to achieve the best discharge performance, it is necessary to activate the PEMFC stack. Therefore, a newly assembled PEMFC stack needs to be activated through a suitable activation process to achieve the best discharge performance. Essentially, the activation is the activation of the MEA. It is generally considered that the activation process includes the humidification of the proton exchange membrane, the establishment of water, proton, electron, and gas channels inside the MEA, the optimization of the electrode structure, and the increase in the exposure of the activation sites of the catalyst Pt particles. Discharge activation is the best way to activate a PEM stack and is also the main method adopted by domestic enterprises. Currently, the large-power PEMFC stacks produced and assembled basically adopt constant current or constant voltage discharge activation, but the activation time of these two methods is as long as several hours or even more than ten hours, which seriously affects the production and testing efficiency of the stack, consumes a large amount of hydrogen, and increases the cost of the PEMFC stack.

[0003] Patent CN117096385A discloses a rapid activation method for a PEM fuel cell, including pre-activation, airtightness inspection, and on-line current control activation steps using an immersion solution prepared with deionized water, acid, and isopropyl alcohol. Before the stack assembly, the MEA needs to be immersed in an acidic solution and an isopropyl alcohol solution, and then repeatedly rinsed with deionized water many times, which increases the stack assembly difficulty, results in low production efficiency, and does not meet the safety requirements of large-scale industrial production. When performing on-line current control activation in this patent, hydrogen is directly introduced into the hydrogen chamber, which easily forms a hydrogen-air interface with the air in the hydrogen chamber, causing performance attenuation of the MEA and affecting the performance of the PEM fuel cell.

[0004] Patent CN113097538A discloses a method for rapid activation of a fuel cell. First, the anode and cathode pipelines are purged with nitrogen to fully discharge the gas in the pipelines, avoiding irreversible damage caused by the hydrogen-air interface at the anode. Then, humidified fuel and oxidant are introduced to maintain a relatively high open-circuit voltage, which can remove the impurities introduced on the surface of the cathode catalyst layer during the preparation of the membrane electrode assembly. Through constant-current loading and operation at a high current, the water generated by the reaction can quickly humidify the membrane electrode assembly. By performing a voltage drop-rise cycle at a high current, the average single-cell voltage of the stack is cycled between high and low potentials, thereby reducing the oxide layer on the surface of the cathode catalyst layer and quickly forming stable transport channels for electrons, ions, gases, and liquids, realizing the rapid activation of the fuel cell stack. Although this patent avoids irreversible damage caused by the hydrogen-air interface at the anode by purging the anode and cathode pipelines with nitrogen, the subsequent activation method is the same as the ordinary activation method, and the required activation time is relatively long. In addition, this patent does not address the issue of treating the catalyst layer.

[0005] Patent CN115064732A discloses a method for activating a proton exchange membrane fuel cell. The activation method includes the following steps: (1) Nitrogen replacement: Place the fuel cell stack on the test platform and perform wet nitrogen replacement on the hydrogen chamber and air chamber of the test platform; (2) Heat up the fuel cell stack; (3) Increase the voltage: Replace the hydrogen chamber with wet hydrogen and the air chamber with wet air again; (4) Secondary nitrogen replacement: Replace the air chamber with wet nitrogen again, and the hydrogen in the hydrogen chamber remains hydrogen, and let it stand; (5) Constant-current discharge cycle: Adjust the hydrogen in the hydrogen chamber, replace the air chamber with wet air, pull the current from the initial current to the preset current, and then lower the load to the initial current, and perform the pull-load-lower-load operation in a cycle until the activation is completed. The activation method provided by this patent has more than 40 discharge cycles and takes nearly 2 hours, with a relatively long activation time, increasing the production cost of the PEMFC stack.

[0006] Methods for activating a PEMFC stack using harsh conditions, such as high-temperature treatment in boiling water or steam before assembling the stack with the MEA, or the method of CO oxidation stripping, etc., do not meet the safety requirements for large-scale industrial production. In addition, the reported activation methods also have disadvantages such as complex activation processes, long activation times, and high hydrogen consumption. Therefore, only by developing a PEMFC stack activation method with a simple activation process, short activation time, and low hydrogen consumption can the requirements of large-scale industrial production be met.

[0007] The currently adopted activation method is prone to form a hydrogen-air interface on the anode side, and the hydrogen-air interface will generate a high potential, causing severe corrosion of the carbon support. The corrosion damage of the hydrogen-air interface mainly occurs on the cathode side. After the carbon support is corroded, phenomena such as the shedding of Pt and the destruction of the three-phase interface will occur. Eventually, the performance of the fuel cell will decline severely, and its severity far exceeds the life attenuation caused by the high potential during the actual operation of the fuel cell. At the same time, carbon corrosion will also occur due to the increase in the cathode potential. The carbon corrosion damages the conductor in the cathode and forces the reconstruction of the electron path, further increasing the ohmic resistance and contact resistance of the cathode. In addition, carbon corrosion will cause the shedding of Pt particles, resulting in a decrease in the catalytically active area, thus reducing the discharge performance of the PEMFC.

[0008] During the preparation of the MEA and the assembly of the PEMFC stack, the Pt particles on the surface of the catalyst layer are easily oxidized to form PtO due to long-term exposure to air 2 , reducing the active sites of the catalyst, thereby reducing the catalytic efficiency of the catalyst, so that the PEMFC stack cannot achieve the best discharge performance even through long-term activation. Summary of the Invention

[0009] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an activation method for a proton exchange membrane fuel cell. The activation method of the present invention is simple, efficient, and has a short time, and can effectively improve the discharge performance.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0012] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen.

[0013] (2) Heat up the proton exchange membrane fuel cell stack, introduce hydrogen into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air into the cavity, and keep it in an open circuit state.

[0014] (3) Perform constant current discharge: Pull the current to 99 - 165 A at the first loading rate and keep it for 1 - 15 min; pull the current to 330 - 396 A at the second loading rate and keep it for 1 - 15 min; reduce the load to open circuit.

[0015] Apply a constant current to the proton exchange membrane fuel cell stack, introduce hydrogen into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce nitrogen into the cavity, and keep it for 1 - 15 min.

[0016] Disconnect the DC power supply, and then switch the nitrogen in the cavity to air and keep the ventilation for 1 - 5 min.

[0017] (4) Repeat the operations in step (3) 1 to 5 times;

[0018] (5) Conduct constant current discharge again: Pull the current to 155 - 175 A at the third loading rate and hold for 1 - 15 min; pull the current to 480 - 520 A at the fourth loading rate and hold for 1 - 15 min; pull the current to 580 - 620 A at the fifth loading rate and hold for 1 - 15 min; reduce the load to open circuit to complete activation.

[0019] The present invention creatively purges the anode and cathode of the proton exchange membrane fuel cell stack with nitrogen first, which can effectively humidify the MEA, remove the impurities introduced on the MEA surface during the assembly of the PEMFC stack, effectively avoid the generation of the hydrogen-air interface, and effectively reduce the risk of MEA performance degradation; then raise the temperature, introduce hydrogen into the hydrogen chamber and air into the cavity, and keep it in an open circuit state to further improve the wetting effect of the MEA and improve the activation performance of the MEA. In addition, the risk of hydrogen-air leakage in the MEA can be quickly diagnosed through the change of the open circuit voltage; then conduct constant current discharge on it, apply a constant current to the proton exchange membrane fuel cell stack, which is beneficial to the establishment of water, proton, electron, and gas channels inside the MEA; introduce hydrogen into the hydrogen chamber of the proton exchange membrane fuel cell stack and nitrogen into the cavity to make the cathode in a state of lacking air. The hydrogen protons conducted from the anode combine with electrons on the cathode side to generate hydrogen, which is beneficial to the reduction reaction of the oxide in the cathode catalyst layer, increase the catalytic reaction active sites, and at the same time optimize the electrode structure and improve the catalyst efficiency, thus significantly improving the discharge performance of the PEMFC. Finally, conduct constant current discharge again, in three stages, gradually increase the current, and finally reduce the load to open circuit, effectively improving the activation effect, making the performance of the PEM stack reach the best state. And the activation time of the present invention is short and can be completed within 50 min, effectively shortening the activation time.

[0020] As a preferred embodiment of the present invention, in step (1), the relative humidity of the nitrogen is 60 - 100%, and the purging time is 1 - 5 min.

[0021] As a preferred embodiment of the present invention, in step (2), the relative humidity of the hydrogen is 60 - 100%; and / or

[0022] In step (2), the relative humidity of the air is 60 - 100%.

[0023] As a preferred embodiment of the present invention, in step (2), the temperature is raised to 60 - 80 °C.

[0024] As a preferred embodiment of the present invention, in step (2), the open circuit voltage ≥ 0.95 V, and the time of maintaining the open circuit state is 1 - 10 min.

[0025] As a preferred embodiment of the present invention, the first pulling rate in step (3) is 0.1 to 10 A / s; and / or

[0026] The second pulling rate in step (3) is 1 to 20 A / s.

[0027] As a preferred embodiment of the present invention, the second pulling rate > the first pulling rate.

[0028] As a preferred embodiment of the present invention, the first pulling rate is 0.1 to 1 A / s.

[0029] As a preferred embodiment of the present invention, the second pulling rate is 1.5 to 8 A / s.

[0030] As a preferred embodiment of the present invention, the second pulling rate / the first pulling rate = 8 to 15.

[0031] In particular, controlling the first pulling rate to be 0.1 to 1 A / s, the second pulling rate to be 1.5 to 2 A / s, and controlling the ratio of the two to be 8 to 15 is beneficial to the establishment of water, proton, electron, and gas channels inside the MEA, facilitating subsequent improvement of the activation sites and improving the discharge performance.

[0032] As a preferred embodiment of the present invention, the constant current is 30 to 150 A.

[0033] As a preferred embodiment of the present invention, the relative humidity of hydrogen in step (3) is 60 to 100%; and / or

[0034] The relative humidity of nitrogen in step (3) is 60 to 100%; and / or

[0035] The relative humidity of air in step (3) is 60 to 100%.

[0036] As a preferred embodiment of the present invention, the third pulling rate, the fourth pulling rate, and the fifth pulling rate in step (5) are each independently 1 to 20 A / s;

[0037] The load reduction rate in step (5) is 20 to 30 A / s.

[0038] The beneficial effects of the present invention are as follows: First, nitrogen purging is carried out on the cathode and anode of the proton exchange membrane fuel cell stack, which can effectively humidify the MEA, remove impurities introduced on the surface of the MEA during the assembly of the PEMFC stack, effectively avoid the generation of the hydrogen-air interface, and effectively reduce the risk of MEA performance degradation; then, the temperature is raised, hydrogen is introduced into the hydrogen chamber, and air is introduced into the cavity, keeping it in an open-circuit state, which further improves the wetting effect of the MEA and enhances the activation performance of the MEA. In addition, the risk of hydrogen-air leakage in the MEA can be quickly diagnosed through the change in the open-circuit voltage; then, constant-current discharge is carried out, applying a constant current to the proton exchange membrane fuel cell stack, which is conducive to the establishment of water, proton, electron, and gas channels inside the MEA; hydrogen is introduced into the hydrogen chamber of the proton exchange membrane fuel cell stack, and nitrogen is introduced into the cavity, making the cathode in a state of lacking air. The hydrogen protons conducted from the anode combine with electrons on the cathode side to generate hydrogen, which is conducive to the reduction reaction of the oxide in the cathode catalyst layer, increasing the catalytic reaction active sites, and at the same time optimizing the electrode structure and improving the catalyst efficiency, thereby significantly improving the discharge performance of the PEMFC. Finally, constant-current discharge is carried out again, in three stages, gradually increasing the current and finally reducing the load to the open circuit, effectively improving the activation effect, making the performance of the PEM stack reach the best state, and the activation time of the present invention is short, which can be completed within 50 minutes, effectively shortening the activation time. Detailed implementation manners

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0040] In the present application, among the technically characterized described in an open-ended manner, it includes a closed technical solution composed of the listed features, and also includes an open technical solution containing the listed features.

[0041] In the present application, regarding the numerical range, unless otherwise specified, the above numerical range is considered continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to an integer, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0042] In the present application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0043] Unless otherwise specified, the component raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the component raw materials used in each parallel experiment are of the same kind.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0045] The following examples are provided to facilitate the understanding of the present invention. These examples are not provided to limit the scope of the claims.

[0046] Example 1

[0047] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0048] An experiment was conducted using a proton exchange membrane fuel cell stack composed of 200 proton exchange membrane fuel cells with a reaction area of 300 cm 2 , and the stack was connected to the test bench with no abnormal airtightness:

[0049] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen at a relative humidity of 100% for 3 min;

[0050] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with a relative humidity of 100% into the cavity, and keep it in an open circuit state for 3 min, with an average open circuit voltage ≥ 0.95 V;

[0051] (3) Perform constant current discharge: Pull the current to 99 A at a pulling rate of 0.5 A / s and keep it for 3 min; Pull the current to 330 A at a pulling rate of 5 A / s and keep it for 3 min; Reduce the load to open circuit at a load reduction rate of 10 A / s;

[0052] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce nitrogen with a relative humidity of 80% into the cavity, keep it for 3 min and then disconnect the DC power supply;

[0053] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 min;

[0054] (4) Repeat the operation of step (3) once;

[0055] (5) Perform constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 495 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 594 A at a loading rate of 10 A / s and hold for 2 min; reduce the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0056] Example 2

[0057] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0058] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 , composed of 200 proton exchange membrane fuel cells, for experiments. Connect the stack to the test bench, and there is no abnormality in airtightness:

[0059] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen with a relative humidity of 100% for 3 min;

[0060] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with a relative humidity of 100% into the cavity, and keep it in an open circuit state for 3 min, with an average open circuit voltage ≥ 0.95 V;

[0061] (3) Perform constant current discharge: Pull the current to 99 A at a loading rate of 0.5 A / s and hold for 3 min; pull the current to 330 A at a loading rate of 5 A / s and hold for 3 min; reduce the load to open circuit at a unloading rate of 10 A / s;

[0062] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce nitrogen with a relative humidity of 80% into the cavity, and disconnect the DC power supply after holding for 3 min;

[0063] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 min;

[0064] (4) Repeat the operation in step (3) 2 times;

[0065] (5) Perform constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 495 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 594 A at a loading rate of 10 A / s and hold for 2 min; reduce the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0066] Example 3

[0067] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0068] Using a proton exchange membrane fuel cell stack composed of 200 proton exchange membrane fuel cells with a reaction area of 300 cm 2 for experiments, connecting the stack to a test bench, and there is no abnormality in airtightness:

[0069] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen having a relative humidity of 100% for 3 min;

[0070] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with a relative humidity of 100% into the cavity, keep it in an open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0071] (3) Perform constant current discharge: Pull the current to 99 A at a loading rate of 0.5 A / s and keep it for 3 min; Pull the current to 330 A at a loading rate of 5 A / s and keep it for 3 min; Reduce the load to open circuit at a unloading rate of 10 A / s;

[0072] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce nitrogen with a relative humidity of 80% into the cavity, keep it for 3 min and then disconnect the DC power supply;

[0073] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 min;

[0074] (4) Repeat the operation of step (3) 3 times;

[0075] (5) Perform constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and keep it for 2 min; Pull the current to 495 A at a loading rate of 10 A / s and keep it for 2 min; Pull the current to 594 A at a loading rate of 10 A / s and keep it for 2 min; Reduce the load to open circuit at a unloading rate of 20 A / s to complete the activation.

[0076] Example 4

[0077] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0078] Using a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2, an experiment was conducted on a proton exchange membrane fuel cell stack composed of 200 proton exchange membrane fuel cells. The stack was connected to the test bench, and the airtightness was normal:

[0079] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen at a relative humidity of 100% for 3 minutes;

[0080] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with a relative humidity of 100% into the cavity. Keep it in an open circuit state for 3 minutes, and the average open circuit voltage ≥ 0.95 V;

[0081] (3) Conduct constant current discharge: Pull the current to 99 A at a loading rate of 0.1 A / s and keep it for 3 minutes; Pull the current to 330 A at a loading rate of 1.5 A / s and keep it for 3 minutes; Reduce the load to open circuit at a unloading rate of 10 A / s;

[0082] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce nitrogen with a relative humidity of 80% into the cavity. After keeping it for 3 minutes, disconnect the DC power supply;

[0083] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 minutes;

[0084] (4) Repeat the operation in step (3) twice;

[0085] (5) Conduct constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and keep it for 2 minutes; Pull the current to 495 A at a loading rate of 10 A / s and keep it for 2 minutes; Pull the current to 594 A at a loading rate of 10 A / s and keep it for 2 minutes; Reduce the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0086] Example 5

[0087] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0088] Use a reaction area of 300 cm 2 , an experiment was conducted on a proton exchange membrane fuel cell stack composed of 200 proton exchange membrane fuel cells. The stack was connected to the test bench, and the airtightness was normal:

[0089] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen at a relative humidity of 100% for 3 minutes;

[0090] (2) Heat up the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce air with a relative humidity of 100% into the cavity, keep it in an open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0091] (3) Conduct constant current discharge: Pull the current to 99 A at a loading rate of 1 A / s and keep it for 3 min; Pull the current to 330 A at a loading rate of 8 A / s and keep it for 3 min; Reduce the load to open circuit at a unloading rate of 10 A / s;

[0092] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce nitrogen with a relative humidity of 80% into the cavity, disconnect the DC power supply after 3 min;

[0093] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 min;

[0094] (4) Repeat the operation in step (3) twice;

[0095] (5) Conduct constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and keep it for 2 min; Pull the current to 495 A at a loading rate of 10 A / s and keep it for 2 min; Pull the current to 594 A at a loading rate of 10 A / s and keep it for 2 min; Reduce the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0096] Example 6

[0097] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0098] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 and consisting of 200 proton exchange membrane fuel cells for experiments, connect the stack to the test bench, and there is no abnormality in airtightness:

[0099] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen with a relative humidity of 100% for 3 min;

[0100] (2) Heat up the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce air with a relative humidity of 100% into the cavity, keep it in an open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0101] (3) Conduct constant current discharge: Pull the current to 99 A at a loading rate of 0.5 A / s and hold for 3 min; pull the current to 330 A at a loading rate of 5 A / s and hold for 3 min; reduce the load to open circuit at a unloading rate of 10 A / s;

[0102] Apply a constant current of 120 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce nitrogen with a relative humidity of 80% into the cavity, and disconnect the DC power supply after holding for 3 min;

[0103] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 min;

[0104] (4) Repeat the operation in step (3) twice;

[0105] (5) Conduct constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 495 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 594 A at a loading rate of 10 A / s and hold for 2 min; reduce the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0106] Comparative Example 1

[0107] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0108] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 and consisting of 200 proton exchange membrane fuel cells for experiments, connect the stack to the test bench, and there is no abnormality in airtightness:

[0109] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen with a relative humidity of 100% for 3 min;

[0110] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce air with a relative humidity of 100% into the cavity, keep it in an open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0111] (3) Conduct constant current discharge: Pull the current to 99 A at a loading rate of 0.5 A / s and hold for 3 min; pull the current to 330 A at a loading rate of 5 A / s and hold for 3 min; reduce the load to open circuit at a unloading rate of 10 A / s;

[0112] (4) Repeat the operation in step (3) twice;

[0113] (5) Perform constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 495 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 594 A at a loading rate of 10 A / s and hold for 2 min; lower the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0114] Comparative Example 2

[0115] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0116] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 and consisting of 200 proton exchange membrane fuel cells for experiments. Connect the stack to the test bench, and there is no abnormality in airtightness:

[0117] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen with a relative humidity of 100% for 3 min;

[0118] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with a relative humidity of 100% into the cavity, and keep it in an open circuit state for 3 min, with an average open circuit voltage ≥ 0.95 V;

[0119] (3) Perform constant current discharge: Pull the current to 99 A at a loading rate of 0.5 A / s and hold for 3 min; pull the current to 330 A at a loading rate of 5 A / s and hold for 3 min; lower the load to open circuit at a unloading rate of 10 A / s;

[0120] (4) Repeat the operation in step (3) 10 times;

[0121] (5) Perform constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 495 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 594 A at a loading rate of 10 A / s and hold for 2 min; lower the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0122] Comparative Example 3

[0123] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0124] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 and consisting of 200 proton exchange membrane fuel cells for experiments. Connect the stack to the test bench, and there is no abnormality in airtightness:

[0125] (1) Purge the anode of the proton exchange membrane fuel cell stack with nitrogen at 100% relative humidity for 3 min;

[0126] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with 100% relative humidity into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with 100% relative humidity into the cavity, keep it in the open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0127] (3) Perform constant current discharge: Pull the current to 99 A at a loading rate of 0.5 A / s and keep it for 3 min; Pull the current to 330 A at a loading rate of 5 A / s and keep it for 3 min; Reduce the load to the open circuit at a unloading rate of 10 A / s;

[0128] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with 80% relative humidity into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce nitrogen with 80% relative humidity into the cavity, keep it for 3 min and then disconnect the DC power supply;

[0129] Then switch the nitrogen in the cavity to air with 80% relative humidity and keep the ventilation for 3 min;

[0130] (4) Repeat the operation in step (3) twice;

[0131] (5) Perform constant current discharge again: Pull the current to 495 A at a loading rate of 10 A / s and keep it for 6 min; Reduce the load to the open circuit at a unloading rate of 20 A / s to complete activation.

[0132] Comparative Example 4

[0133] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0134] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 and consisting of 200 proton exchange membrane fuel cells for experiments, connect the stack to the test bench, and there is no abnormality in airtightness:

[0135] (1) Purge the anode of the proton exchange membrane fuel cell stack with nitrogen at 100% relative humidity for 3 min;

[0136] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with 100% relative humidity into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce air with 100% relative humidity into the cavity, keep it in the open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0137] (3) Perform constant current discharge: Pull the current to 99 A at a loading rate of 10 A / s and hold for 3 min; pull the current to 330 A at a loading rate of 25 A / s and hold for 3 min; unload to open circuit at a unloading rate of 10 A / s;

[0138] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply, introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce nitrogen with a relative humidity of 80% into the cavity, and disconnect the DC power supply after holding for 3 min;

[0139] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and keep the ventilation for 3 min;

[0140] (4) Repeat the operation in step (3) twice;

[0141] (5) Perform constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 495 A at a loading rate of 10 A / s and hold for 2 min; pull the current to 594 A at a loading rate of 10 A / s and hold for 2 min; unload to open circuit at a unloading rate of 20 A / s to complete activation.

[0142] Comparative Example 5

[0143] An activation method for a proton exchange membrane fuel cell, comprising the following steps:

[0144] Use a proton exchange membrane fuel cell stack with a reaction area of 300 cm 2 and consisting of 200 proton exchange membrane fuel cells for experiments, connect the stack to the test bench, and there is no abnormality in airtightness:

[0145] (1) Purge the anode and anode of the proton exchange membrane fuel cell stack with nitrogen with a relative humidity of 100% for 3 min;

[0146] (2) Heat the proton exchange membrane fuel cell stack to 70 °C, introduce hydrogen with a relative humidity of 100% into the hydrogen chamber of the proton exchange membrane fuel cell stack, introduce air with a relative humidity of 100% into the cavity, keep it in an open circuit state for 3 min, and the average open circuit voltage ≥ 0.95 V;

[0147] (3) Perform constant current discharge: Pull the current to 99 A at a loading rate of 15 A / s and hold for 3 min; pull the current to 330 A at a loading rate of 20 A / s and hold for 3 min; unload to open circuit at a unloading rate of 10 A / s;

[0148] Apply a constant current of 60 A to the proton exchange membrane fuel cell stack through a DC power supply. Introduce hydrogen with a relative humidity of 80% into the hydrogen chamber of the proton exchange membrane fuel cell stack, and introduce nitrogen with a relative humidity of 80% into the cavity. After maintaining for 3 min, disconnect the DC power supply;

[0149] Then switch the nitrogen in the cavity to air with a relative humidity of 80% and maintain ventilation for 3 min;

[0150] (4) Repeat the operation in step (3) 2 times;

[0151] (5) Conduct constant current discharge again: Pull the current to 165 A at a loading rate of 10 A / s and maintain for 2 min; Pull the current to 495 A at a loading rate of 10 A / s and maintain for 2 min; Pull the current to 594 A at a loading rate of 10 A / s and maintain for 2 min; Reduce the load to open circuit at a unloading rate of 20 A / s to complete activation.

[0152] Test example

[0153] After activation by the methods of the above-mentioned examples and comparative examples respectively, the PEMFC stack is subjected to discharge performance tests. Pull the load at a loading rate of 20 A / s. The operating conditions are a stack temperature of 70 °C, a gas stoichiometric ratio of 1.4 / 1.8 for the anode and cathode, a gas relative humidity of 60% / 40% for the anode and cathode, and anode and cathode pressures of 150 / 120 kPa respectively. At a current density of 1.8 A / cm 2 The average voltage is shown in Table 1.

[0154] Table 1

[0155]

[0156]

[0157] It can be seen from Table 1 that the activation method of the present invention is simple, efficient, and time-saving, and can effectively improve the discharge performance.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for activating a proton exchange membrane fuel cell, characterized in that: The following steps are involved: (1) nitrogen is passed through the anode and cathode of the proton exchange membrane fuel cell stack for purging; (2) heating the proton exchange membrane fuel cell stack, introducing hydrogen into the hydrogen cavity of the proton exchange membrane fuel cell stack, and introducing air into the cavity, maintaining an open circuit state; (3) Performing constant current discharge: loading the current to 99~165A at the first loading rate and maintaining it for 1~15min; loading the current to 330~396A at the second loading rate and maintaining it for 1~15min; reducing the load to an open circuit; the first loading rate is 0.1~10 A / s; the second loading rate is 1~20 A / s; Apply a constant current to the proton exchange membrane fuel cell stack, introduce hydrogen into the hydrogen cavity of the proton exchange membrane fuel cell stack, and introduce nitrogen into the cavity, and maintain for 1 to 15 minutes; the constant current is 30 to 150A; Disconnect the DC power supply, then switch the nitrogen in the cavity to air and keep ventilation for 1 to 5 minutes; (4) Repeat step (3) 1 to 5 times; (5) Perform constant current discharge again: load the current to 155~175A at the third loading rate and maintain for 1~15min; Load the current to 480~520A at the fourth loading rate and keep it for 1~15min; load the current to 580~620A at the fifth loading rate and keep it for 1~15min; reduce the load to open circuit to complete activation; The third loading rate, the fourth loading rate, and the fifth loading rate are each independently 1-20 A / s; the load reduction rate is 20-30 A / s; The entire activation time of the proton exchange membrane fuel cell activation method is within 50 minutes.

2. The method for activating a proton exchange membrane fuel cell according to claim 1, characterized in that: The relative humidity of the nitrogen in step (1) is 60-100%, and the purge time is 1-5 min.

3. The method for activating a proton exchange membrane fuel cell according to claim 1, characterized in that: The relative humidity of the hydrogen in step (2) is 60-100%; and / or The relative humidity of the air in step (2) is 60-100%.

4. The method for activating a proton exchange membrane fuel cell according to claim 1, characterized in that: The step (2) is heating to a temperature of 60-80°C.

5. The method for activating a proton exchange membrane fuel cell according to claim 1, characterized in that: In step (2), the open circuit voltage is ≥ 0.95 V, and the open circuit state is maintained for 1 to 10 minutes.

6. The method for activating a proton exchange membrane fuel cell according to claim 1, characterized in that: The second loading rate / the first loading rate=8~15.

7. The method for activating a proton exchange membrane fuel cell according to claim 1, characterized in that: The relative humidity of the hydrogen in step (3) is 60-100%; and / or The relative humidity of the nitrogen in step (3) is 60-100%; and / or The relative humidity of the air in step (3) is 60-100%.

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