A simulated fuel cell system shutdown apparatus and method

Abstract

The application relates to a simulated fuel cell system shutdown device and method, which comprises a stack module, air input modules and hydrogen input modules for respectively providing air and hydrogen to cavities and oxygen cavities of the stack module, a water heat circulation module in circulation communication with a water cavity in the stack module, a battery test module for detecting the voltage of the stack module, and an oxygen consumption module comprising a discharge resistor and a switch breaker electrically connected between the positive and negative electrodes of the stack module. Compared with the prior art, the application simulates the system shutdown process by adjusting corresponding parameters, detects the real-time change of hydrogen and air pressure and other parameters, and achieves the effects of avoiding incomplete oxygen consumption and adjusting appropriate hydrogen and air pressure difference.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology and relates to a device and method for simulating the shutdown of a fuel cell system. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a device that converts hydrogen and oxygen into electrical energy through an electrochemical reaction. It is widely used in transportation, portable power supplies, and power plants. In practical applications, the fuel cell stack needs to be matched with appropriate auxiliary systems to form a fuel cell system for operation. The appropriateness of the shutdown operation after operation directly affects the system's subsequent performance output and service life.

[0003] When a fuel cell system is shut down, it undergoes an oxygen consumption process. If oxygen is not completely consumed at the cathode and permeates to the anode, or if oxygen leaks in from the outside due to sealing issues and cannot be continuously consumed, oxygen will appear at the anode. Upon the next startup, when hydrogen is introduced into the anode, a hydrogen-air interface is formed. When a hydrogen-oxygen reaction occurs at the anode, a current flows in this region opposite to the normal fuel cell mode, creating a high potential at the cathode interface. This leads to carbon corrosion of the cathode catalyst layer, affecting the stack's performance and lifespan. Secondly, after a period of shutdown, a significant hydrogen-air negative pressure may occur, resulting in an excessively large hydrogen-air pressure differential when hydrogen is introduced into the stack upon normal startup, damaging the membrane electrode assembly (MEA).

[0004] Chinese patent CN113130946A discloses a control method and system for shutting down a fuel cell. In this method, after the supply of reactants is stopped during the fuel cell shutdown procedure, the remaining reactants are consumed using an adjustable load. The consumption status of the reactants is determined by detecting the hydrogen pressure and the fuel cell voltage. However, the determination method of this technology is affected by factors such as hydrogen flow rate, initial pressure, and hydrogen-air leakage, resulting in a large deviation in the determination and making it impossible to fully consume oxygen.

[0005] Chinese patent CN113809366A discloses a shutdown control method for a fuel cell system. The main invention involves determining whether to shut down the fuel cell system by the relationship between the cumulative hydrogen flow rate and a preset threshold. The preset threshold is equal to the amount of hydrogen in the air-side cavity minus the amount of hydrogen in the hydrogen-side cavity. The amount of hydrogen is calculated using parameters such as the pressure, volume, and temperature of the cavity at shutdown and the preset hydrogen concentration at startup. Since the calculation requires many parameters, and the pressure and temperature changes at shutdown or the hydrogen concentration at startup are affected by factors such as shutdown duration, sealing, and leakage, the preset threshold may be disturbed or need to be continuously adjusted, increasing the complexity of the system program.

[0006] The above-mentioned technical solutions all directly control the shutdown process through the auxiliary system at the fuel cell system end. The judgment method is subject to interference from multiple factors, which may lead to design deviations or increase complexity and make it impossible to accurately match the characteristics of the fuel cell stack. Furthermore, due to the coupling effect of the auxiliary system, it is impossible to accurately determine the actual internal state of the fuel cell stack after shutdown. Summary of the Invention

[0007] The purpose of this invention is to provide a device and method for simulating the shutdown of a fuel cell system. By adjusting relevant parameters, the system shutdown is simulated, and the real-time changes in parameters such as hydrogen-air pressure are detected. This achieves the effects of avoiding incomplete oxygen consumption and adjusting the appropriate hydrogen-air pressure difference. It is matched with a shutdown control method suitable for the fuel cell stack and corresponding system, and applied to system control, simplifying the system adjustment complexity and improving the reliability of the shutdown judgment program. Furthermore, this device can be adjusted accordingly for different fuel cell stacks and different auxiliary systems, making it widely applicable.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A device for simulating the shutdown process of a fuel cell system, comprising:

[0010] fuel cell stack module;

[0011] The air input module and the hydrogen input module are used to supply air and hydrogen to the cavity and oxygen cavity of the fuel cell stack module, respectively.

[0012] The hydrothermal circulation module is circulated with the water chamber in the fuel cell stack module;

[0013] The battery test module is used to detect the voltage of the battery stack module; and

[0014] The oxygen consumption module includes a discharge resistor and a switching circuit breaker that are electrically connected between the positive and negative terminals of the fuel cell module.

[0015] Furthermore, the stack module includes a fuel cell stack, the hydrothermal circulation module includes a circulating constant temperature water bath, and the battery testing module includes a battery tester.

[0016] Furthermore, the air input module includes an air outlet control valve, and an air storage tank, an air intake pressure reducing valve, and an air path inlet control valve connected sequentially along the air flow direction.

[0017] The air outlet control valve is connected to the cavity outlet, and the air inlet control valve is connected to the cavity inlet.

[0018] Furthermore, an air pressure gauge is provided between the air inlet control valve and the cavity inlet.

[0019] Furthermore, an air pressure sensor is provided between the air intake pressure reducing valve and the air inlet control valve.

[0020] Furthermore, the hydrogen input module includes a hydrogen outlet control valve, and a hydrogen storage tank, a hydrogen inlet pressure reducing valve, and a hydrogen inlet control valve connected sequentially along the air flow direction.

[0021] The hydrogen outlet control valve is connected to the hydrogen chamber outlet, and the hydrogen inlet control valve is connected to the hydrogen chamber inlet.

[0022] Furthermore, a hydrogen dilution device is also provided after the hydrogen outlet control valve.

[0023] A method for simulating the shutdown process of a fuel cell system based on the above-mentioned device includes the following steps:

[0024] S1: Start the hydrothermal circulation module to heat the fuel cell stack to the set temperature; start the battery test module to detect the fuel cell stack voltage;

[0025] S2: Air at a set pressure P0 is introduced into the cavity of the fuel cell stack module through the air input module, and air at a set pressure P is introduced into the hydrogen cavity of the fuel cell stack module through the hydrogen input module. H Hydrogen gas;

[0026] S3: Stop the air supply and close the cavity inlet and outlet; continue to supply hydrogen and close the hydrogen cavity outlet;

[0027] S4: Turn on the switch circuit breaker and discharge through the discharge resistor with a resistance of R; control the hydrogen gas introduction time to t1, and then close the hydrogen chamber inlet;

[0028] S5: When the battery test module detects that the voltage of the stack module is lower than the threshold voltage U, disconnect the switch circuit breaker;

[0029] S6: Record the changes in hydrogen cavity pressure and cavity pressure over time in steps S1-S5, as well as the correspondence between hydrogen cavity pressure and cavity pressure and voltage changes, and determine the oxygen consumption and the internal state of the stack at different times.

[0030] Furthermore, in step S5, the threshold voltage U is 0.001n V, where n is the number of individual cells contained in the stack.

[0031] Furthermore, in step S6, the oxygen consumption is determined by the change in the hydrogen cavity pressure difference and the voltage. When P 空腔 -P 氢腔 When the maximum voltage is reached, it is assumed that the oxygen has been almost completely consumed, and the internal environment of the fuel cell stack is a mixture of hydrogen and nitrogen. At this point, the total voltage can be confirmed to be <0.01nV.

[0032] Internal status assessment of the fuel cell stack: Based on the change in cavity pressure over time, the duration of negative pressure in the cavity is recorded to avoid excessive hydrogen-air pressure difference during startup; Based on the change in hydrogen cavity pressure over time, the minimum hydrogen cavity pressure and the duration of negative pressure are recorded, which can be used to assess hydrogen pressure and duration during the next startup to avoid excessively uneven local hydrogen pressure distribution during startup.

[0033] Furthermore, this method also includes, after step S6, adjusting the air pressure P0 and the hydrogen pressure P, respectively. H The discharge resistor value R and the hydrogen gas introduction time t1 are determined, and steps S1-S5 are repeated to obtain optimized shutdown operation conditions.

[0034] Compared with the prior art, the present invention has the following characteristics:

[0035] 1) This invention simulates the fuel cell stack temperature during system shutdown by controlling the hydrothermal circulation module; simulates different system gas chamber volumes by changing the pipeline cavity volumes of the air input module and hydrogen input module; simulates system shutdown purging and gas stoppage by controlling the opening and closing of the gas inlet and outlet valves; simulates the rate of reactant consumption during system shutdown by switching discharge resistors with different internal resistance values; and simulates system monitoring of voltage changes during shutdown by determining the stack voltage through a voltage detection device.

[0036] By adjusting the relevant parameters to simulate the system shutdown process, the real-time changes of parameters such as hydrogen-air pressure are detected, thereby achieving the effects of avoiding incomplete oxygen consumption and adjusting the appropriate hydrogen-air pressure difference.

[0037] 2) This invention can simulate shutdown operations for fuel cells with different characteristics, match appropriate shutdown control methods, and has a wide range of applications;

[0038] 3) This invention can be adjusted accordingly using different auxiliary systems, making it highly versatile;

[0039] 4) The corresponding shutdown control method in this invention can be applied to system control, simplifying system adjustment complexity and improving the reliability of shutdown judgment program. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a simulated fuel cell system shutdown device according to the present invention;

[0041] Figure 2 The curve showing the change in hydrogen chamber pressure during the shutdown process in Example 1;

[0042] Figure 3 The curve showing the change in hydrogen chamber pressure during the shutdown process in Example 2;

[0043] Figure 4The curve showing the change in hydrogen chamber pressure during the shutdown process in Example 3;

[0044] Explanation of markings in the diagram:

[0045] 100 - Hydrothermal cycle module; 200 - Battery testing module; 300 - Fuel cell stack module; 400 - Oxygen consumption module; 500 - Air input module; 600 - Hydrogen input module;

[0046] 1-Air storage tank; 2-Air inlet pressure reducing valve; 3-Air pressure sensor; 4-Air inlet control valve; 5-Air pressure gauge; 6-Air outlet control valve; 7-Circulating constant temperature water bath; 8-Battery tester; 9-Fuel cell stack; 10-Discharge resistor; 11-Switch circuit breaker; 12-Hydrogen outlet control valve; 13-Hydrogen pressure gauge; 14-Hydrogen inlet control valve; 15-Hydrogen pressure sensor; 16-Hydrogen inlet pressure reducing valve; 17-Hydrogen storage tank. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 1 The device shown is a simulation device for the shutdown process of a fuel cell system, including

[0049] The fuel cell stack module 300 includes the fuel cell stack 9 and the pipeline connecting the hydrogen cavity. The volume of the module pipeline can be adjusted according to the total volume between the inlet shut-off valve and the outlet shut-off valve of the hydrogen cavity in the system to match the hydrogen cavity conditions of the system.

[0050] An air input module 500 is used to supply air to the cavity of the fuel cell stack module 300. It includes an air outlet control valve 6, and an air storage tank 1, an air inlet pressure reducing valve 2, and an air path inlet control valve 4 connected sequentially along the air flow direction. The air outlet control valve 6 is connected to the cavity outlet, and the air path inlet control valve 4 is connected to the cavity inlet. An air pressure gauge 5 is installed between the air path inlet control valve 4 and the cavity inlet. An air pressure sensor 3 is installed between the air inlet pressure reducing valve 2 and the air path inlet control valve 4. The air inlet pressure is adjusted by controlling the pressure reducing valve, and the air pressure gauge records real-time pressure changes.

[0051] The hydrogen input module 600 is used to supply hydrogen to the hydrogen chamber of the fuel cell stack module 300. It includes a hydrogen outlet control valve 12, and a hydrogen storage tank 17, a hydrogen inlet pressure reducing valve 16, and a hydrogen inlet control valve 14 connected in sequence along the air flow direction. The hydrogen outlet control valve 12 is connected to the hydrogen chamber outlet, and the hydrogen inlet control valve 14 is connected to the hydrogen chamber inlet. The hydrogen inlet pressure is adjusted by controlling the pressure reducing valve, and the real-time pressure change is recorded by a hydrogen pressure gauge. The tail of the hydrogen outlet control valve can be connected to a hydrogen dilution device to ensure safe hydrogen emission.

[0052] Preferably, a hydrogen dilution device is also provided after the hydrogen outlet control valve 12.

[0053] The hydrothermal circulation module 100 includes a circulating constant temperature water bath 7 and a circulation pipeline that circulates the circulating constant temperature water bath 7 to the water chamber of the fuel cell stack 9. It can connect to the water chamber inlet and outlet of the fuel cell stack. By setting the water bath temperature and starting the water circulation mode, the stack is heated to achieve the required stack temperature conditions to simulate the stack temperature when the system is shut down.

[0054] The battery testing module 200 includes a battery tester 8 and test leads, which are connected to the positive and negative terminals of the fuel cell stack to detect real-time voltage changes.

[0055] The oxygen consumption module 400 includes a discharge resistor 10 electrically connected between the positive and negative terminals of the fuel cell module 300, a switch breaker 11, and wires; the oxygen consumption rate is adjusted by replacing the discharge resistor with different resistance values, and the process of the controller consuming hydrogen and oxygen when the system is shut down is simulated by controlling the on and off of the switch.

[0056] A method for simulating the shutdown of a fuel cell system includes the following steps:

[0057] S1: Start the water-thermal circulation module 100 to heat the fuel cell stack module 300 to the set temperature; start the battery test module 200 to detect the voltage of the fuel cell stack module 300;

[0058] S2: Air at a set pressure P0 is introduced into the cavity of the fuel cell stack module 300 through the air input module 500, and air at a set pressure P is introduced into the hydrogen cavity of the fuel cell stack module 300 through the hydrogen input module 600. H Hydrogen gas;

[0059] S3: Stop the air supply and close the cavity inlet and outlet; continue to supply hydrogen and close the hydrogen cavity outlet;

[0060] S4: Turn on the switch breaker 11, and discharge through the discharge resistor 10 with a resistance of R; control the hydrogen gas introduction time to t1, and then close the hydrogen chamber inlet;

[0061] S5: When the battery test module 200 detects that the voltage of the stack module 300 is lower than the threshold voltage U, the switch breaker 11 is disconnected; where the threshold voltage U is 0.001n V, and n is the number of individual cells contained in the stack.

[0062] S6: Record the changes in hydrogen cavity pressure and cavity pressure over time in steps S1-S5, as well as the correspondence between hydrogen cavity pressure, cavity pressure and voltage changes, and determine the oxygen consumption and the internal state of the fuel cell stack at different times:

[0063] Oxygen consumption is assessed by changes in the hydrogen cavity pressure difference and voltage. 空腔 -P 氢腔 When the maximum voltage is reached, it is assumed that the oxygen has been almost completely consumed, and the internal environment of the fuel cell stack is a mixture of hydrogen and nitrogen. At this point, the total voltage can be confirmed to be <0.01nV.

[0064] Internal status assessment of the fuel cell stack: Based on the change in cavity pressure over time, the duration of negative pressure in the cavity is recorded to avoid excessive hydrogen-air pressure difference during startup; Based on the change in hydrogen cavity pressure over time, the minimum hydrogen cavity pressure and the duration of negative pressure are recorded, which can be used to assess hydrogen pressure and duration during the next startup to avoid excessively uneven local hydrogen pressure distribution during startup.

[0065] Preferably, after step S6, the air pressure P0 and hydrogen pressure P are adjusted respectively. H Set the discharge resistor 10 resistance value R, hydrogen gas introduction time t1, and repeat steps S1-S5 to obtain optimized shutdown operation conditions.

[0066] In the above steps, the oxygen consumption and the internal reduction state of the fuel cell stack at different times are determined based on the changes in hydrogen chamber pressure and air chamber pressure over time and their correspondence with voltage changes. This is achieved by adjusting the hydrogen pressure P. H A shutdown control method suitable for the fuel cell stack and corresponding system is formulated based on factors such as the holding time t1, discharge resistor value R, voltage threshold U, and cavity volume V.

[0067] This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0068] Example 1: Adjusting the hydrogen pressure holding time t1

[0069] Step 1: According to Figure 1 The structural diagram shows the test setup, with all valves closed initially. The fuel cell stack is then connected to the test setup.

[0070] Step 2: Turn on the circulating constant temperature water bath, set the water bath temperature and start the circulation, heat the fuel cell stack to the set temperature T1 and then stop heating;

[0071] Step 3: Turn on the battery test module and perform stack voltage detection;

[0072] Step 4: Adjust the pressure of the hydrogen inlet pressure reducing valve to P, open the hydrogen outlet control valve, adjust the pressure of the air inlet pressure reducing valve to P0, and open the air outlet control valve.

[0073] Step 5: Simultaneously open the air inlet control valve and the hydrogen inlet control valve to ventilate the fuel cell stack for a duration of T.

[0074] Step 6: Close the air inlet control valve and the air outlet control valve, and close the hydrogen outlet control valve;

[0075] Step 7: Simultaneously turn on the oxygen consumption module switch to discharge and consume the hydrogen and oxygen gas in the fuel cell stack;

[0076] Step 8: After the hydrogen pressure is maintained for time t1, close the hydrogen inlet control valve;

[0077] Step 9: When the battery stack voltage detected by the battery tester drops to the voltage threshold U, disconnect the oxygen consumption module switch;

[0078] Step 10: Continue to record the pressure changes in the hydrogen and air chambers using an air pressure gauge and a hydrogen pressure gauge throughout the process, with a recording duration of Tx.

[0079] Change the hydrogen holding time t1 to tn (n = 1, 2, 3...), repeat steps 1 to 10, and compare the trend of hydrogen cavity pressure change under different parameter conditions. Figure 2 Based on the test results of this embodiment, the extreme and stable values ​​of the hydrogen cavity can be adjusted by changing the holding time. Furthermore, the pressure performance inside the reactor can be determined at different times after shutdown by considering the length of the shutdown and startup intervals. By simulating the system shutdown process, a suitable holding pressure can be selected for system shutdown control.

[0080] Example 2: Adjusting the hydrogen holding pressure

[0081] Step 1: According to Figure 1 The structural diagram shows the test setup, with all valves closed initially. The fuel cell stack is then connected to the test setup.

[0082] Step 2: Turn on the circulating constant temperature water bath, set the water bath temperature and start the circulation, heat the fuel cell stack to the set temperature T1 and then stop heating;

[0083] Step 3: Turn on the battery test module and perform stack voltage detection;

[0084] Step 4: Adjust the pressure of the hydrogen inlet pressure reducing valve to P1, open the hydrogen outlet control valve, adjust the pressure of the air inlet pressure reducing valve to P0, and open the air outlet control valve.

[0085] Step 5: Simultaneously open the air inlet control valve and the hydrogen inlet control valve to ventilate the fuel cell stack for a duration of T.

[0086] Step 6: Close the air inlet control valve and the air outlet control valve, and close the hydrogen outlet control valve;

[0087] Step 7: Simultaneously turn on the oxygen consumption module switch to discharge and consume the hydrogen and oxygen gas in the fuel cell stack;

[0088] Step 8: After maintaining the hydrogen pressure for time tn, close the hydrogen inlet control valve;

[0089] Step 9: When the battery stack voltage detected by the battery tester drops to the voltage threshold U, disconnect the oxygen consumption module switch;

[0090] Step 10: Continue to record the pressure changes in the hydrogen and air chambers using an air pressure gauge and a hydrogen pressure gauge throughout the process, with a recording duration of Tx.

[0091] Change the hydrogen holding pressure P1 to Pn (n = 1, 2, 3...), repeat steps 1 to 10, and compare the trend of hydrogen cavity pressure change under different parameter conditions. Figure 3 To verify the test results of this embodiment, the extreme and stable values ​​of the hydrogen cavity pressure can be adjusted by changing the holding pressure. Furthermore, the pressure performance within the reactor at different times after shutdown can be determined by the length of the shutdown and startup intervals. By simulating the system shutdown process, a suitable holding time can be selected for system shutdown control.

[0092] Example 3: Adjusting the total volume of the gas chamber

[0093] Step 1: According to Figure 1 The structural diagram shows the test device being built. The initial state is that all valves are closed. The fuel cell stack is connected to the test device, and a pipe with a volume of V1 is connected between the cavity and the air pressure gauge.

[0094] Step 2: Turn on the circulating constant temperature water bath, set the water bath temperature and start the circulation, heat the fuel cell stack to the set temperature T1 and then stop heating;

[0095] Step 3: Turn on the battery test module and perform stack voltage detection;

[0096] Step 4: Adjust the pressure of the hydrogen inlet pressure reducing valve to Pn, open the hydrogen outlet control valve, adjust the pressure of the air inlet pressure reducing valve to P0, and open the air outlet control valve.

[0097] Step 5: Simultaneously open the air inlet control valve and the hydrogen inlet control valve to ventilate the fuel cell stack for a duration of T.

[0098] Step 6: Close the air inlet control valve and the air outlet control valve, and close the hydrogen outlet control valve;

[0099] Step 7: Simultaneously turn on the oxygen consumption module switch to discharge and consume the hydrogen and oxygen gas in the fuel cell stack;

[0100] Step 8: After maintaining the hydrogen pressure for time tn, close the hydrogen inlet control valve;

[0101] Step 9: When the battery stack voltage detected by the battery tester drops to the voltage threshold U, disconnect the oxygen consumption module switch;

[0102] Step 10: Continue to record the pressure changes in the hydrogen and air chambers using an air pressure gauge and a hydrogen pressure gauge throughout the process, with a recording duration of Tx.

[0103] Change the pipe volume V1 to Vn (n = 1, 2, 3...), repeat steps 1 to 10, and compare the trend of hydrogen cavity pressure change under different parameter conditions. Figure 4 To obtain the test results from this embodiment, the volume of the pipe connecting the cavity and the hydrogen cavity can be changed for different auxiliary systems matched to the fuel cell stack. The total volume of the gas cavity on the system can be fitted, and the system shutdown process can be simulated by different total gas volumes. The appropriate auxiliary system can then be matched based on the test results.

[0104] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for simulating the shutdown process of a fuel cell system, characterized in that, The apparatus used includes fuel cell stack module (300); The air input module (500) and the hydrogen input module (600) are used to supply air and hydrogen to the cavity and oxygen cavity of the fuel cell stack module (300), respectively. The hydrothermal circulation module (100) is circulated with the water cavity in the fuel cell stack module (300); A battery test module (200) is used to detect the voltage of the battery stack module (300); as well as The oxygen consumption module (400) includes a discharge resistor (10) and a switch disconnector (11) electrically connected between the positive and negative terminals of the fuel cell module (300). Simulation methods include S1: Start the hydrothermal circulation module (100) to heat the fuel cell stack module (300) to the set temperature; start the battery test module (200) to detect the voltage of the fuel cell stack module (300); S2: Air at a set pressure P0 is introduced into the cavity of the fuel cell stack module (300) through the air input module (500), and air at a set pressure P is introduced into the hydrogen cavity of the fuel cell stack module (300) through the hydrogen input module (600). H Hydrogen gas; S3: Stop the air supply and close the cavity inlet and outlet; continue to supply hydrogen and close the hydrogen cavity outlet; S4: Turn on the switch circuit breaker (11) and discharge through the discharge resistor (10) with a resistance of R; control the hydrogen gas introduction time to t1, and then close the hydrogen chamber inlet; S5: When the battery test module (200) detects that the voltage of the stack module (300) is lower than the threshold voltage U, disconnect the switch (11). S6: Record the changes in hydrogen cavity pressure and cavity pressure over time in steps S1-S5, as well as the correspondence between hydrogen cavity pressure and cavity pressure and voltage changes, and determine the oxygen consumption and the internal state of the stack at different times. In step S5, the threshold voltage U is 0.001n V, where n is the number of individual cells in the stack; In step S6, the method for determining oxygen consumption includes: judging by changes in the hydrogen cavity pressure difference and voltage; when P... 空腔 -P 氢腔 When the maximum value is reached, it is determined that the oxygen has been completely consumed, and at this point, the total voltage is confirmed to be <0.01nV; Internal state assessment of the fuel cell stack: The internal state is assessed based on the change in cavity pressure over time, and the duration of negative pressure in the cavity is recorded; the internal state is assessed based on the change in hydrogen cavity pressure over time, and the minimum pressure and duration of negative pressure in the hydrogen cavity are recorded for use in determining hydrogen pressure and duration at the next startup.

2. The method for simulating the shutdown process of a fuel cell system according to claim 1, characterized in that, The fuel cell stack module (300) includes a fuel cell stack (9), the hydrothermal circulation module (100) includes a circulating constant temperature water bath (7), and the battery testing module (200) includes a battery tester (8).

3. The method for simulating the shutdown process of a fuel cell system according to claim 1, characterized in that, The air input module (500) includes an air outlet control valve (6), and an air storage tank (1), an air inlet pressure reducing valve (2), and an air path inlet control valve (4) connected sequentially along the air flow direction. The air outlet control valve (6) is connected to the cavity outlet, and the air inlet control valve (4) is connected to the cavity inlet.

4. The method for simulating the shutdown process of a fuel cell system according to claim 3, characterized in that, An air pressure gauge (5) is provided between the air inlet control valve (4) and the cavity inlet.

5. The method for simulating the shutdown process of a fuel cell system according to claim 3, characterized in that, An air pressure sensor (3) is provided between the air intake pressure reducing valve (2) and the air path inlet control valve (4).

6. The method for simulating the shutdown process of a fuel cell system according to claim 1, characterized in that, The hydrogen input module (600) includes a hydrogen outlet control valve (12), and a hydrogen storage tank (17), a hydrogen inlet pressure reducing valve (16), and a hydrogen inlet control valve (14) connected sequentially along the air flow direction. The hydrogen outlet control valve (12) is connected to the hydrogen chamber outlet, and the hydrogen inlet control valve (14) is connected to the hydrogen chamber inlet.

7. The method for simulating the shutdown process of a fuel cell system according to claim 6, characterized in that, A hydrogen dilution device is also provided after the hydrogen outlet control valve (12).

8. The method for simulating the shutdown process of a fuel cell system according to claim 1, characterized in that, It also includes adjusting the air pressure P0 and the hydrogen pressure P after step S6. H The discharge resistor (10) resistance value R, the hydrogen gas introduction time t1, and the steps S1-S5 are repeated to obtain optimized shutdown operation conditions.

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