Fuel cell membrane electrode rapid aging and performance evaluation test system

Abstract

The application discloses a kind of fuel cell membrane electrode quick aging and performance evaluation test system, including gas supply module, CO gas and hydrogen gas are mixed to form mixed gas, humidification module and heating module are used to control the humidity and temperature of gas respectively;Back pressure control module is used to control the back pressure of membrane electrode cathode and anode flow channel, while removing tail gas;Membrane electrode assembly module is used to clamp membrane electrode, provides membrane electrode cathode and anode gas flow channel and reaction environment;Control analysis module is used to monitor each electronic component of the whole test system, while being equipped with electronic load for controlling the end potential of membrane electrode and receiving the current output of membrane electrode, to analyze the performance of membrane electrode.The application can test and evaluate the performance of membrane electrode in various environments, while providing CO impurity gas, simulating various special working conditions to make membrane electrode quickly age, verifying and analyzing the influence of aging degree under different working conditions, so as to facilitate the study of membrane electrode aging mechanism.

Description

Technical Field

[0001] This invention relates to the field of fuel cell testing, and in particular to a test system for rapid aging and performance evaluation of fuel cell membrane electrodes. Background Technology

[0002] Hydrogen fuel cell technology is one of the important energy use methods in the future. As a key component of fuel cells, the membrane electrode assembly (MEA) is of great significance for the research and optimization of fuel cells by testing and evaluating its performance.

[0003] Proton exchange membrane fuel cells (PEMFCs) use phosphorus (Pt) as the electrocatalyst. Copper oxide (CO) is a strong poison for Pt, readily adsorbing onto the catalyst surface and hindering catalytic oxidation of the fuel, significantly reducing catalyst utilization. Studies show that even 10⁻⁴% CO can introduce a large overpotential to the anode. Furthermore, industrial hydrogen production often involves CO, meaning the final hydrogen may contain CO impurities, damaging the catalyst and affecting membrane electrode performance. Current membrane electrode testing systems are limited in capability and cost for single membrane electrodes. In actual operation, membrane electrodes often face special conditions such as start-up / shutdown, humidity cycling, and fuel starvation. Additionally, the presence of CO impurities during hydrogen production can poison the catalyst and cause failure. Operating in these environments leads to membrane electrode damage and rapid aging, resulting in performance degradation. Therefore, testing systems must not only evaluate the performance of membrane electrodes under normal operating conditions but also simulate special conditions to analyze and evaluate their performance after rapid aging under these conditions. Summary of the Invention

[0004] This invention addresses the shortcomings of current traditional testing systems in terms of testing capabilities by providing a rapid aging and performance evaluation test system for fuel cell membrane electrodes. This system can test and evaluate the performance of membrane electrodes in various environments, and can also provide CO impurity gas to simulate various special operating conditions to rapidly age the membrane electrodes, verify and analyze the impact of different operating conditions on the degree of aging, thereby facilitating the study of the aging mechanism of membrane electrodes.

[0005] The objective of this invention is achieved through the following technical solution: a rapid aging and performance evaluation test system for fuel cell membrane electrode assembly, comprising: a gas supply module, a humidification module, a heating module, a back pressure control module, a membrane electrode assembly module, and a control and analysis module;

[0006] The gas supply module includes a CO gas pipeline, an air pipeline, a hydrogen pipeline, and a nitrogen pipeline. CO gas and hydrogen gas are mixed to form a mixed gas. The nitrogen pipeline is connected to the hydrogen pipeline and the air pipeline after the nitrogen pressure regulating valve. The nitrogen pipeline is also connected to the cylinder pipeline in the membrane electrode assembly module.

[0007] The humidification module and the heating module are used to control the humidity and temperature of the gas, respectively;

[0008] The back pressure control module is used to control the back pressure of the anode and cathode channels of the membrane electrode, and at the same time to exhaust exhaust gas.

[0009] The membrane electrode assembly module is used to clamp the membrane electrode and provide gas flow channels and reaction environment for the membrane electrode anode and cathode.

[0010] The control and analysis module is used to monitor each module of the entire test system. It is also equipped with an electronic load to control the terminal potential of the membrane electrode and receive the current output of the membrane electrode, so as to obtain the polarization curve, open circuit voltage, cyclic volt-ampere characteristic curve, and voltage-time curve under steady-state conditions of the membrane electrode, and then analyze the performance of the membrane electrode.

[0011] Furthermore, each gas supply in the gas supply module is supplied by a high-pressure standard gas cylinder, controlled by a ball valve, controlled by a pressure regulating valve, and controlled by a mass flow controller. CO gas and hydrogen gas are mixed in a gas mixing tank after passing through the mass flow controller to form a mixed gas, which is used to simulate hydrogen gas that may contain a certain amount of CO impurities in actual situations.

[0012] Furthermore, the humidification module includes an air humidification pipeline and a hydrogen humidification pipeline. Each pipeline is equipped with a solenoid valve, deionized water and a bubble humidifier, a humidity sensor and a drying pipeline. The solenoid valve controls whether the gas passes through the bubble humidifier, enabling rapid switching between dry and humidified gas. The bubble humidifier contains deionized water and is equipped with a heating rod, humidifying the gas based on the dew point temperature principle. The humidity sensor measures the humidity of the gas at the fixture inlet and feeds it back to the intelligent instrument, thereby controlling the operating voltage of the heating rod in the bubble humidifier.

[0013] Furthermore, the heating module includes an air heating pipeline and a hydrogen heating pipeline, each pipeline being equipped with an outer layer of insulation cotton, a heating belt, and a thermocouple; the heating pipeline is used to maintain the humidity and temperature of the gas after humidification, so that the gas reaches the reaction temperature before reaching the membrane electrode, while preventing water vapor in the gas from condensing and affecting the reaction humidity.

[0014] Furthermore, the back pressure control module includes a hydrogen pipeline proportional valve and an air pipeline proportional valve, which are used to control the back pressure of the anode and cathode channels during the membrane electrode reaction, so that the gas in the channels can fully participate in the reaction.

[0015] Furthermore, the membrane electrode assembly module includes a cylinder pressure regulating valve, a clamp solenoid valve, a cylinder, and a membrane electrode clamp; wherein, the membrane electrode clamp is used to clamp the test membrane electrode, providing anode and cathode flow channels and a reaction environment, and the clamp is equipped with a heating rod and a thermocouple for precise control of the reaction temperature; the cylinder is used to provide external pressure for clamping the membrane electrode, the clamp solenoid valve controls the opening and closing of the cylinder, and the cylinder pressure regulating valve controls the clamping force.

[0016] Furthermore, the control and analysis module includes an electronic control system, a touch screen, a host computer, and an electronic load. The electronic control system collects data from thermocouples, mass flow sensors, and pressure sensors, and controls various electronic components in the experimental system, including solenoid valves, mass flow controllers, and heating devices. The touch screen is directly connected to the electronic control system and can directly monitor various experimental data and control various electronic components when the host computer is occupied. The host computer receives data signals collected by the electronic control system and sends experimental requirements to the electronic control system and the electronic load, thereby controlling the experimental conditions of the membrane electrode. The electronic load can test the polarization curve, open-circuit voltage, cyclic volt-ampere characteristic curve, and voltage-time curve under steady-state conditions of the membrane electrode, thus providing direct data support for the performance analysis of the membrane electrode.

[0017] The beneficial effects of this invention are:

[0018] 1. This test system can realize a variety of rapid aging tests and combinations of different aging methods. Compared with the traditional test system, a CO impurity gas pipeline has been added, which can test and analyze the effect of CO impurity gas on membrane electrode aging under different operating conditions.

[0019] 2. This experimental system adopts a distributed control system, which can not only accurately acquire and control various parameters, but also realize the linkage of multiple control parameters, including the control between current and flow rate, temperature and humidity.

[0020] 3. The entire test system adopts a modular design, which facilitates later optimization and adjustment and can be improved according to test requirements. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 Schematic diagram of the structure of the fuel cell membrane electrode rapid aging and performance evaluation test system.

[0023] Figure 2 Schematic diagram of the control method of the rapid aging and performance evaluation test system for fuel cell membrane electrode assembly.

[0024] Figure 3 Schematic diagram of flow closed-loop regulation.

[0025] Figure 4 Schematic diagram of humidity closed-loop regulation.

[0026] Figure 5 Schematic diagram of closed-loop temperature regulation. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] like Figure 1 and Figure 2 As shown, the rapid aging and performance evaluation test system for fuel cell membrane electrodes of this invention can generate various operating conditions simulating the actual working environment of the membrane electrode required for testing through standard gas distribution, humidification by a bubble humidifier, heating by heating pipelines, and electronic load control terminal potential. The entire test system mainly includes six modules: gas supply module, humidification module, heating module, back pressure control module, membrane electrode assembly module, and control and analysis module.

[0029] The gas supply module provides hydrogen and air for the membrane electrode reaction, nitrogen for gas washing and fixture clamping, and CO is mixed into the hydrogen as needed for the experiment to simulate impurities that may be present in the actual hydrogen production process. The gas supply module includes hydrogen, air, nitrogen, and CO gas lines. Each gas line is supplied by a high-pressure standard gas cylinder, controlled by a ball valve, with the inlet pressure controlled by a pressure regulating valve and the inlet flow rate controlled by a mass flow controller. The hydrogen line is sequentially equipped with a hydrogen source 2, a hydrogen pressure regulating valve 6, a hydrogen mass flow controller 10, and a gas mixing tank 12, before connecting to the hydrogen humidification line. The air line is sequentially equipped with an air source 4, an air pressure regulating valve 8, and an air mass flow controller 11, before connecting to the air humidification line. The nitrogen pipeline is sequentially equipped with a nitrogen source 3 and a nitrogen pressure regulating valve 7. The nitrogen source 3 is also connected to the inlet of the cylinder pressure regulating valve 26 of the membrane electrode assembly module. The outlet pipeline of the nitrogen pressure regulating valve 7 is connected to the hydrogen pipeline and the air pipeline respectively, and a one-way valve is installed in between to ensure that the gas can only flow from the nitrogen pipeline to the hydrogen pipeline and the air pipeline. The CO gas pipeline is sequentially equipped with a CO source 1, a CO pressure regulating valve 5, and a CO mass flow controller 9. Finally, it is introduced into the gas mixing tank 12 to mix with hydrogen, which is used to simulate hydrogen that may contain a certain amount of CO impurities in actual situations.

[0030] The aforementioned mass flow controllers are all controlled by intelligent instruments. According to experimental requirements, the flow rate demands for hydrogen, air, and CO are sent to the intelligent instrument via a host computer or touchscreen. The intelligent instrument then sends a current signal to the mass flow controller and receives the flow rate signal returned by the mass flow controller. If the flow rate is too low, the current signal is increased, and vice versa. A schematic diagram of the flow closed-loop regulation is shown below. Figure 3 As shown. Before and after the experiment, shut off the hydrogen, air, and CO gas sources, and open the nitrogen pressure regulating valve 7 to flush out any residual gas in the gas path and avoid affecting the experiment.

[0031] The gas humidification module controls the humidity of air and hydrogen, including air humidification lines and hydrogen humidification lines. Each line is equipped with a solenoid valve (hydrogen humidification solenoid valve 13, air humidification solenoid valve 16), deionized water and a bubble humidifier (hydrogen bubble humidifier 14, air bubble humidifier 17), and a drying line. The solenoid valve controls whether the gas passes through the bubble humidifier, enabling rapid switching between dry and humidified gas. The bubble humidifier contains deionized water and a heating rod, humidifying the gas based on the dew point temperature principle. A humidity sensor measures the humidity of the gas at the fixture inlet and feeds it back to the intelligent instrument, which then controls the operating voltage of the heating rod in the bubble humidifier. The outlet of the humidification line connects to the heating line, and humidity sensors (hydrogen humidity sensor 18, air humidity sensor 15) are installed after the heating line. Whether the gas is humidified is controlled by the solenoid valves, and the PLC directly controls the state of the solenoid valves to guide the gas through the bubble humidifier or directly into the heating line. If humidification is used, the gas humidity is controlled by an intelligent instrument. After passing through the bubble humidifier, the gas is saturated, and its absolute humidity is related to the temperature of the deionized water inside the bubble humidifier. The intelligent instrument receives humidity information from the humidity sensor. If the humidity is lower than the test requirements, the voltage regulation module increases the heating power of the heating rod inside the bubble humidifier to raise its temperature until the target humidity is reached, and vice versa. A schematic diagram of the humidity closed-loop regulation is shown below. Figure 4 As shown.

[0032] The gas heating module is used to heat the gas and maintain its humidity, ensuring that the gas reaches the required experimental temperature and maintains the necessary humidity before reaching the membrane electrode. The gas heating module includes a hydrogen heating line 19, an air heating line 20, a hydrogen thermocouple 21, and an air thermocouple 22. Each line is equipped with an outer layer of insulation and a heating element. The heating lines maintain the humidity and temperature of the gas after humidification, ensuring that the gas reaches the reaction temperature before reaching the membrane electrode, while preventing water vapor condensation from affecting the reaction humidity. The power of the heating element in the heating line is jointly controlled by an intelligent instrument and a voltage regulation module. The gas temperature measured by the thermocouples is transmitted to the intelligent instrument. When the temperature is lower than the experimental set value, the heating power of the heating element is increased, and vice versa. A schematic diagram of the temperature closed-loop regulation is shown below. Figure 5 As shown.

[0033] The back pressure assembly module is mainly used to control the back pressure of the anode and cathode channels of the membrane electrode and to exhaust the tail gas. It assembles the cathode proportional valve 27 and the anode proportional valve 28, which are respectively connected to the anode and cathode channels in the membrane electrode fixture and the atmosphere. The opening degree is controlled by the host computer to control the back pressure of the anode and cathode channels during the membrane electrode reaction, so that the gas in the channel can fully participate in the reaction.

[0034] The membrane electrode assembly module is used to clamp the membrane electrode and provide anode and cathode flow channels and a reaction environment. Its main components include a clamping solenoid valve 26, a cylinder pressure regulating valve 25, a cylinder 24, and a membrane electrode clamp 23. The inlet of the cylinder pressure regulating valve 26 is connected to a nitrogen pipeline, controlling the pressure of nitrogen entering the cylinder 24. The clamping solenoid valve 25 controls the opening and closing of the clamp by changing the flow direction of nitrogen. The membrane electrode clamp 23 is used to clamp the membrane electrode, with clamping pressure provided by the cylinder and regulated by the cylinder pressure regulating valve 25. The upper and lower sides of the cylinder are bipolar plates containing anode and cathode flow channels. The cathode flow channel inlet connects to the air heating pipeline outlet, and the anode flow channel inlet connects to the hydrogen heating pipeline outlet. Heating rods and thermocouples are also inserted inside the clamp, and their internal temperature is jointly controlled by intelligent instruments and the pressure regulating module.

[0035] The control and analysis module monitors all electronic components of the entire experimental system, primarily the electronic control system, touchscreen, host computer, and electronic load. The electronic control system and touchscreen monitor various parameters of the entire experimental system, including the on / off state of the gas path and gas temperature, humidity, and pressure data. The electronic load controls the terminal potential of the membrane electrode and receives the current output of the membrane electrode. It can receive and control the output voltage, current, and power of the membrane electrode, thereby testing its performance, including polarization curves, open-circuit voltage, cyclic volt-ampere characteristic curves, and voltage-time curves under steady-state conditions, thus providing direct data support for membrane electrode performance analysis. The touchscreen is directly connected to the electronic control system and can directly monitor various experimental data and control various electronic control components when the host computer is occupied. The host computer receives data signals collected by the electronic control system and sends experimental requirements to the electronic control system and electronic load, thereby controlling the experimental conditions of the membrane electrode. The host computer provides a human-machine interface for convenient operation, setting, and saving of experimental data.

[0036] The performance evaluation of the membrane electrode assembly (MEA) mainly focuses on analyzing its output characteristics. After installing the MEA under test, the nitrogen source 3, air source 4, and hydrogen source 2 are manually turned on. The hydrogen pressure regulating valve 6, air pressure regulating valve 8, cathode proportional valve 27, anode proportional valve 28, and cylinder pressure regulating valve 26 are adjusted to ensure appropriate gas pressures. The required air humidity, hydrogen humidity, air temperature, hydrogen temperature, and MEA reaction temperature are set via the host computer. After the test conditions are met, the output characteristics of the MEA, mainly the polarization curve, are controlled and detected by setting the electronic load. The polarization curve describes the static characteristics of the fuel cell. Starting from 0, current values ​​are set at certain intervals. After each current value is stabilized for a period of time, the curve formed by the change in output voltage with current after stabilization is recorded; this curve is the polarization curve.

[0037] Rapid aging of membrane electrodes mainly focuses on the performance failure of membrane electrodes under specific environments, including start-stop conditions, idling conditions, overload conditions, load cycle conditions, humidity cycle conditions, and gas impurities.

[0038] The start-stop conditions described primarily simulate the frequent start-stop cycles of the membrane electrode assembly (MEA), which can lead to air entering the anode and forming a hydrogen-oxygen interface. This results in a localized high potential on the cathode side, accelerating the corrosion of the carbon support and Pt catalyst. During the experiment, the gas temperature, humidity, and flow rate were first set. Hydrogen and air were then introduced into the anode and cathode respectively and maintained for a period of time to simulate normal fuel cell operation. Then, the reactor was shut down according to the experimental control methods, and residual gas in the flow channels was purged until the stack voltage dropped to below half of the open-circuit voltage. After a period of rest, the reactor was restarted, and this process was repeated multiple times.

[0039] The idling condition primarily simulates the aging of fuel cell cells under low load. Under low load or idling conditions, the fuel cell membrane electrode assembly (MEA) is at a high potential, which can lead to corrosion of the carbon support and Pt catalyst, and also cause decomposition of the proton exchange membrane. The test process involves an electronic load maintaining the MEA at an extremely low current for a set period of time.

[0040] The overload condition mainly simulates the overload operation of a fuel cell. Under this condition, a large amount of water is generated, which can easily cause flooding. At the same time, the utilization rate of the reactant gas increases under high load, which can lead to excessively low hydrogen or oxygen concentrations, resulting in a starvation state, or even the formation of reverse electrode. The test process involves the electronic load maintaining the membrane electrode assembly at a high current for a set period of time.

[0041] The load cycling test simulates the alternating operation of a fuel cell under different loads. Under these conditions, changes in the water content of the membrane electrode assembly (MEA) and the aggregation of the Pt catalyst occur, leading to accelerated corrosion of the proton exchange membrane and the catalyst. The test process employs high- and low-potential cyclic testing.

[0042] The humidity cycling test simulates the periodic changes in the relative humidity of the intake air, leading to either dryness or waterlogging of the membrane electrode assembly (MEA), which can cause aging and damage to the proton exchange membrane. The host computer controls the humidification solenoid valve to periodically change whether the gas passes through the humidifier at the humidification module, simulating a dry-wet gas cycle. The humidity is controlled by adjusting the temperature of the deionized water in the bubbling humidifier, and the MEA is operated for a set period of time under the established test conditions.

[0043] The main gaseous impurity is hydrogen, which is often accompanied by CO as a byproduct during industrial production, resulting in impurities in the hydrogen. The experiment simulates this impurity by controlling the CO gas pipeline. During the experiment, the CO impurity content in the hydrogen was controlled by regulating the CO mass flow controller in the CO gas pipeline, and the gas was then introduced into the membrane electrode assembly and operated under set conditions for a period of time.

[0044] The aforementioned operating conditions all cause damage to different parts of the membrane electrode, leading to membrane electrode aging. By simulating these conditions, the aging rate of the membrane electrode can be accelerated, thereby allowing for the study of the aging mechanism. This experimental system can well meet the above experimental requirements and also support experiments under combined operating conditions.

[0045] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A rapid aging and performance evaluation test system for fuel cell membrane electrodes, characterized in that, include: Gas supply module, humidification module, heating module, back pressure control module, membrane electrode assembly module, and control and analysis module; The gas supply module includes a CO gas pipeline, an air pipeline, a hydrogen pipeline, and a nitrogen pipeline. CO and hydrogen are mixed to form a mixed gas. The nitrogen pipeline connects to the hydrogen and air pipelines after the nitrogen pressure regulating valve. The nitrogen pipeline is also connected to the cylinder pipeline in the membrane electrode assembly module. Each gas supply line in the module is supplied by a high-pressure standard gas cylinder, controlled by a ball valve, with the inlet pressure controlled by a pressure regulating valve and the inlet flow rate controlled by a mass flow controller. Specifically, after passing through the mass flow controller, CO and hydrogen are mixed in a gas mixing tank to form a mixed gas, simulating hydrogen that may contain a certain amount of CO impurities in actual conditions. The humidification module and the heating module are used to control the humidity and temperature of the gas, respectively; The humidification module includes an air humidification pipeline and a hydrogen humidification pipeline. The air humidification pipeline and the hydrogen humidification pipeline are each equipped with a solenoid valve, deionized water and a bubble humidifier, a humidity sensor, and a drying pipeline, respectively. The solenoid valve controls whether the gas passes through the bubble humidifier, enabling rapid switching between drying and humidifying gas. The bubble humidifier contains deionized water and a heating rod, humidifying the gas based on the dew point temperature principle. The humidity sensor measures the gas humidity and feeds it back to the intelligent instrument, thereby controlling the operating voltage of the heating rod inside the bubble humidifier. The heating module includes an air heating pipe and a hydrogen heating pipe, each equipped with an outer layer of insulation cotton, a heating belt, and a thermocouple. The heating pipe is used to maintain the humidity and temperature of the gas after humidification, so that the gas reaches the reaction temperature before reaching the membrane electrode, while preventing water vapor in the gas from condensing and affecting the reaction humidity. The back pressure control module is used to control the back pressure of the anode and cathode channels of the membrane electrode, and at the same time to exhaust exhaust gas. The membrane electrode assembly module is used to clamp the membrane electrode and provide the anode and cathode flow channels and reaction environment for the membrane electrode. The control and analysis module is used to monitor each module of the test system. It is also equipped with an electronic load to control the terminal potential of the membrane electrode and receive the current output of the membrane electrode, so as to obtain the polarization curve, open circuit voltage, cyclic volt-ampere characteristic curve, and voltage-time curve under steady-state conditions of the membrane electrode, and then analyze the performance of the membrane electrode.

2. The rapid aging and performance evaluation test system for fuel cell membrane electrodes according to claim 1, characterized in that, The back pressure control module includes a hydrogen pipeline proportional valve and an air pipeline proportional valve, which are used to control the back pressure of the anode and cathode channels during the membrane electrode reaction, so that the gas in the channels can fully participate in the reaction.

3. The rapid aging and performance evaluation test system for fuel cell membrane electrodes according to claim 1, characterized in that, The membrane electrode assembly module includes a cylinder pressure regulating valve, a clamp solenoid valve, a cylinder, and a membrane electrode clamp. The membrane electrode clamp is used to clamp and test the membrane electrode, providing anode and cathode flow channels and a reaction environment. The membrane electrode clamp is equipped with a heating rod and a thermocouple for precise control of the reaction temperature. The cylinder is used to provide external pressure to clamp the membrane electrode. The clamp solenoid valve controls the opening and closing of the cylinder, and the cylinder pressure regulating valve controls the clamping force.

4. The rapid aging and performance evaluation test system for fuel cell membrane electrodes according to claim 1, characterized in that, The control and analysis module includes an electronic control system, a touch screen, a host computer, and an electronic load. The electronic control system collects data from thermocouples, mass flow sensors, and pressure sensors, and controls various electronic components in the experimental system, including solenoid valves, mass flow controllers, and heating devices. The touch screen is directly connected to the electronic control system and can directly monitor various experimental data and control various electronic components when the host computer is occupied. The host computer receives data signals collected by the electronic control system and sends experimental requirements to the electronic control system and the electronic load, thereby controlling the experimental conditions of the membrane electrode. The electronic load can test the polarization curve, open-circuit voltage, cyclic volt-ampere characteristic curve, and voltage-time curve under steady-state conditions of the membrane electrode, thus providing direct data support for the performance analysis of the membrane electrode.

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