A stack purge flow calibration device for hydrogen fuel cells

Abstract

The application provides a kind of calibrating device for the stack ventilation purging flow of hydrogen fuel cell, belongs to fuel cell technical field, solve the problem that existing technology does not consider the increasing amount of hydrogen leakage when calibrating ventilation flow and the influence of complex and changeable environmental factors.The method comprises PACK, compressed air source, compressed hydrogen source, first regulating valve, second regulating valve, first flowmeter, second flowmeter, hydrogen concentration sensor.PACK shell is provided with stack purging gas inlet, stack purging gas outlet and hydrogen leakage gas inlet.The stack purging gas inlet is connected to the compressed air source through the first flowmeter and the first regulating valve in sequence.The stack purging gas outlet is connected to the outdoor calibration device chamber.The hydrogen leakage gas inlet is connected to the compressed hydrogen source through the second flowmeter and the second regulating valve in sequence.The hydrogen leakage gas inlet is arranged in the low flow rate area on the PACK.The hydrogen concentration sensor is arranged in multiple positions in the PACK to measure the hydrogen concentration distribution in the PACK.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell stack ventilation and purging flow calibration device for hydrogen fuel cells. Background Technology

[0002] With the promotion of national new energy policies, hydrogen fuel cells are being used more widely in the automotive field. As a crucial power source for hydrogen fuel cell systems, the fuel cell stack directly impacts the system's performance and reliability. The stack core comprises bipolar plates, membrane electrode assemblies (MEAs), electrode plates, and sealing elements, all encapsulated within the stack under pressure. Sealing elements, typically located between electrode plates and between electrode plates and MEAs, serve to seal, insulate, support, and absorb vibration and shock.

[0003] The operating environment of fuel cell stacks includes wet-dry cycles, acidity, pressure fluctuations, compression variations, and high and low temperatures. This complex and variable environment leads to a decline in the sealing performance of sealing elements, especially since leaked hydrogen can accumulate inside the stack, posing an explosion risk to high and low pressure components. Currently, the primary method to prevent this danger is through ventilation purging to dilute the hydrogen inside the stack. Ventilation flow rate is a key factor in this approach. Excessive flow rate increases air demand, affecting engine performance and posing a risk of stack casing deformation. Insufficient flow rate leads to incomplete hydrogen purging, resulting in hydrogen accumulation.

[0004] Current ventilation flow rate calibration methods are performed when hydrogen leakage within the fuel cell stack's initial encapsulation module is minimal, failing to account for the impact of high-volume hydrogen leakage from moisture and complex, variable environments. As fuel cells age, hydrogen leakage will gradually increase, placing higher demands on existing purging methods, which will no longer meet ventilation and purging requirements. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a fuel cell stack ventilation and purging flow rate calibration device to solve the problem that the existing technology does not consider the increase in hydrogen leakage and the influence of complex and variable environmental factors when calibrating ventilation flow rate.

[0006] On one hand, embodiments of the present invention provide a fuel cell stack ventilation and purging flow calibration device, including a PACK with a built-in fuel cell stack to be calibrated, a compressed air source, a compressed hydrogen source, a first regulating valve, a second regulating valve, a first flow meter, a second flow meter, and several hydrogen concentration sensors.

[0007] The PACK housing is provided with a fuel cell purge inlet, a fuel cell purge outlet, and a hydrogen leak inlet; the fuel cell purge inlet is connected to a compressed air source via a first flow meter and a first regulating valve; the fuel cell purge outlet is connected to the outdoor area of ​​the calibration device; the hydrogen leak inlet is connected to a compressed hydrogen source via a second flow meter and a second regulating valve.

[0008] The hydrogen leak inlet is located in the low-flow-rate area of ​​the PACK; hydrogen concentration sensors are located in multiple different locations within the PACK to measure the hydrogen concentration distribution within the PACK; low flow rate means that the gas flow rate in the area does not exceed 20% of the compressed air flow rate at the fuel cell purge inlet.

[0009] The beneficial effects of the above technical solution are as follows: It provides a new calibration device for ventilation and purging flow rate. By adding an external pipeline (the hydrogen leakage inlet is connected to a compressed hydrogen source sequentially via a second flow meter and a second regulating valve), hydrogen leakage is simulated. Based on the hydrogen concentration fluid simulation results, the hydrogen leakage inlet is positioned at a low flow velocity location. By considering the sealing characteristics between the bipolar plate and the membrane electrode, and between the bipolar plates, the hydrogen leakage flow rate of the pipeline is controlled. This allows for the determination of hydrogen concentration at different locations within the fuel cell stack under different ventilation flow rates, enabling assessment of whether design requirements are met and thus calibrating the required airflow rate. While minimizing the impact on fuel cell performance and air compressor components, it achieves the purpose of purging hydrogen, ensuring that the hydrogen concentration quickly reaches a safe threshold.

[0010] Based on further improvements to the above-mentioned device, the fuel cell stack ventilation and purging flow rate calibration device further includes an environmental simulation device; wherein, the environmental simulation device further includes:

[0011] The dry-wet cycle simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after repeated operation in dry and wet conditions;

[0012] The acid environment simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in an acidic state.

[0013] The air pressure fluctuation simulation unit is located indoors where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in an air pressure fluctuation environment.

[0014] Furthermore, the environmental simulation device also includes:

[0015] The high and low temperature environment simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in a high or low temperature environment.

[0016] Furthermore, the fuel cell stack ventilation and purging flow rate calibration device also includes a first temperature and pressure sensor and a second temperature and pressure sensor; wherein, the first temperature and pressure sensor is located at the front end of the fuel cell stack purging inlet, and the second temperature and pressure sensor is located at the front end of the hydrogen leakage inlet; and,

[0017] The PACK housing is also equipped with a first waterproof and breathable valve and a second waterproof and breathable valve; among which,

[0018] The first waterproof vent valve is installed on the battery pack purge inlet side of the PACK, and the second waterproof vent valve is installed on the battery pack purge outlet side of the PACK. The two valves are used to balance the internal and external pressure of the PACK and prevent water and water vapor from entering the PACK.

[0019] The hydrogen leak inlet is located on one side of the PACK's non-fuel pile purge inlet and fuel pile purge outlet.

[0020] Furthermore, there are seven hydrogen concentration sensors, namely:

[0021] The first hydrogen concentration sensor is installed outside the first waterproof and breathable valve of the PACK.

[0022] The second hydrogen concentration sensor is installed outside the second waterproof and breathable valve of the PACK.

[0023] The third hydrogen concentration sensor is installed at the purge outlet of the fuel cell stack inside the PACK.

[0024] The fourth, fifth, sixth, and seventh hydrogen concentration sensors are evenly distributed on the top of the PACK.

[0025] Furthermore, the hydrogen leak inlet is located at the bottom of the PACK.

[0026] Furthermore, the fuel cell stack ventilation and purging flow rate calibration device also includes a controller; the controller executes the following program to complete the fuel cell stack ventilation and purging flow rate calibration function:

[0027] S1. Start the first regulating valve and acquire data from the first flow meter and the first temperature and pressure sensor;

[0028] S2. Start the second regulating valve and acquire data from the second flow meter and the second temperature and pressure sensor;

[0029] S3. Adjust the opening of the first regulating valve and the second regulating valve multiple times to simulate the fuel cell stack ventilation and purging flow rate under different hydrogen leakage amounts, and obtain the hydrogen concentration values ​​from the first hydrogen concentration sensor to the seventh hydrogen concentration sensor.

[0030] S4. Compare the hydrogen concentration values ​​of the first to seventh hydrogen concentration sensors with the design value to identify whether all hydrogen concentration values ​​are less than or equal to the design value. If so, end the calibration and output the fuel cell purge flow rate corresponding to the opening degree of the first regulating valve; otherwise, repeat steps S3 to S4.

[0031] Furthermore, after activating the first regulating valve in step S1, the battery pack inside the PACK is purged with an air flow rate greater than 0.2 m / s; and,

[0032] In step S2, the opening of the second regulating valve is adjusted so that the hydrogen leakage flow rate exceeds the design safe flow rate;

[0033] In step S3, during the adjustment of the opening of the first regulating valve, the air velocity is always greater than 0.2 m / s.

[0034] Furthermore, the PACK incorporates multiple fuel cell stacks to be calibrated, simulating multi-stack fuel cells.

[0035] Furthermore, the PACK can be a fuel cell-integrated PACK or a laboratory PACK simulator; for a fuel cell-integrated PACK, the device also includes an auxiliary unit for drilling holes in the PACK to create a hydrogen leak inlet; and,

[0036] For a dual-stack fuel cell with one stack above the other, the first waterproof vent valve is located above the stack purge inlet, and the second waterproof vent valve is located above the stack purge outlet. The stack purge inlet and the stack purge outlet are located on opposite diagonals of the PACK housing.

[0037] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or essential features of the invention, nor is it intended to limit the scope of the invention. Attached Figure Description

[0038] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0039] Figure 1 A schematic diagram of the fuel cell stack ventilation and purging flow rate calibration device of Embodiment 1 is shown;

[0040] Figure 2 A schematic diagram of the fuel cell stack ventilation and purging flow rate calibration device in Example 2 is shown.

[0041] Figure 3 A schematic diagram of the calibration process in Example 2 is shown. Detailed Implementation

[0042] Embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0043] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0044] Example 1

[0045] One embodiment of the present invention discloses a device for calibrating the purge flow rate of a hydrogen fuel cell stack, such as... Figure 1 As shown, it includes a PACK with a built-in fuel cell stack to be calibrated, a compressed air source, a compressed hydrogen source, a first regulating valve, a second regulating valve, a first flow meter, a second flow meter, and several hydrogen concentration sensors.

[0046] The PACK housing is equipped with a fuel cell purge inlet, a fuel cell purge outlet, and a hydrogen leak inlet. The fuel cell purge inlet is connected to a compressed air source via a first flow meter and a first regulating valve. The fuel cell purge outlet is connected to the outdoor area of ​​the calibration device. The hydrogen leak inlet is connected to a compressed hydrogen source via a second flow meter and a second regulating valve.

[0047] Hydrogen leak inlets are located in low-flow-rate areas of the PACK. Hydrogen concentration sensors are placed at multiple locations within the PACK to measure the hydrogen concentration distribution within the PACK. Low flow rate refers to the gas flow velocity in the area not exceeding 20% ​​of the compressed air flow velocity at the fuel cell purge inlet.

[0048] Preferably, the fuel cell stack purging flow rate calibration device further includes a first temperature and pressure sensor and a second temperature and pressure sensor. The first temperature and pressure sensor is located at the front end of the fuel cell stack purging inlet, and the second temperature and pressure sensor is located at the front end of the hydrogen leakage inlet. The second temperature and pressure sensor is used to detect the temperature and pressure of the hydrogen entering the encapsulation module.

[0049] During implementation, compressed air enters the fuel cell stack via a first regulating valve, and the airflow rate is monitored by a first flow meter. Compressed hydrogen enters the fuel cell stack via a second regulating valve, and the hydrogen flow rate is monitored by a second flow meter. The location of the hydrogen leakage inlet should be determined based on the fluid simulation results within the packaging module and placed in a low-flow-rate region.

[0050] Compared to existing technologies, the fuel cell stack ventilation and purging flow rate calibration device provided in this embodiment adds an external pipeline (the hydrogen leakage inlet is connected to a compressed hydrogen source sequentially via a second flow meter and a second regulating valve) to simulate hydrogen leakage. Based on the hydrogen concentration fluid simulation results, the hydrogen leakage inlet is positioned at a low flow rate. By considering the sealing characteristics between the bipolar plate and the membrane electrode assembly, and between the bipolar plates, the hydrogen leakage flow rate of the pipeline is controlled. This allows for the determination of hydrogen concentration at different locations within the fuel cell stack under different ventilation flow rates, assessing whether design requirements are met, and thus calibrating the required airflow rate. This achieves the purpose of purging hydrogen while minimizing the impact on fuel cell performance and air compressor components, enabling the hydrogen concentration to quickly reach a safe threshold.

[0051] Example 2

[0052] Based on Example 1, the improved fuel cell stack ventilation and purging flow calibration device further includes a first temperature and pressure sensor and a second temperature and pressure sensor, such as... Figure 2 As shown. The first temperature and pressure sensor is located at the front end of the fuel cell purge inlet, and the second temperature and pressure sensor is located at the front end of the hydrogen leak inlet. The second temperature and pressure sensor is used to detect the temperature and pressure of the hydrogen entering the encapsulation module.

[0053] Preferably, the fuel cell stack ventilation and purging flow calibration device further includes an environmental simulation device. This environmental simulation device further includes a dry-wet cycle simulation unit, an acidic environment simulation unit, a pressure fluctuation simulation unit, a compression-variable environment simulation unit, and a high-low temperature environment simulation unit.

[0054] The dry-wet cycle simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after repeated operation in dry and wet conditions.

[0055] The acid environment simulation unit is located indoors where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in an acidic state.

[0056] The air pressure fluctuation simulation unit is located indoors where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in an air pressure fluctuation environment.

[0057] The high and low temperature environment simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in a high or low temperature environment.

[0058] A temperature and pressure sensor 1 is connected to the front end of the ventilation and purging air inlet to detect the temperature and pressure of the air entering the encapsulation module.

[0059] Preferably, the PACK housing is further provided with a first waterproof vent valve and a second waterproof vent valve. The first waterproof vent valve is installed on the battery pack purge inlet side of the PACK, and the second waterproof vent valve is installed on the battery pack purge outlet side of the PACK. The two valves are used to balance the internal and external pressure of the PACK and prevent water and water vapor from entering the encapsulation module and affecting its protective performance. When the pressure inside the module exceeds its limit, the waterproof vent valve will burst open and needs to be replaced in time after damage.

[0060] The hydrogen leak inlet is located on one side of the PACK's non-fuel pile purge inlet and fuel pile purge outlet.

[0061] Preferably, there are seven hydrogen concentration sensors, namely a first hydrogen concentration sensor, a second hydrogen concentration sensor, a third hydrogen concentration sensor, a fourth hydrogen concentration sensor, a fifth hydrogen concentration sensor, a sixth hydrogen concentration sensor, and a seventh hydrogen concentration sensor.

[0062] The first hydrogen concentration sensor is installed outside the first waterproof and breathable valve of the PACK.

[0063] The second hydrogen concentration sensor is installed outside the second waterproof and breathable valve of the PACK.

[0064] The third hydrogen concentration sensor is installed at the purge outlet of the fuel cell stack inside the PACK to detect the hydrogen concentration at the fuel cell stack outlet.

[0065] The fourth, fifth, sixth, and seventh hydrogen concentration sensors are evenly distributed on the top of the PACK. That is, four hydrogen concentration sensors are placed at the four corners of the top to detect the hydrogen concentration inside the package module (PACK).

[0066] Preferably, the hydrogen leakage inlet is located at the bottom of the PACK. According to the internal fluid simulation results of the package module, the bottom of the PACK is a low-flow-rate region.

[0067] Preferably, the fuel cell stack ventilation purging flow calibration device also includes a controller.

[0068] The controller executes the following procedure to complete the calibration function of the fuel cell stack ventilation purging flow rate:

[0069] S0. Activate the environmental simulation device and set the environmental conditions;

[0070] S1. Start the first regulating valve and acquire data from the first flow meter and the first temperature and pressure sensor; preferably, after starting the first regulating valve in step S1, purge the battery pack inside the PACK with an air flow rate greater than 0.2 m / s, which can ensure that there are no dead corners inside the PACK;

[0071] S2. Start the second regulating valve and acquire data from the second flow meter and the second temperature and pressure sensor; preferably, taking into account the influence of the usage environment and lifespan on the sealing characteristics between the bipolar plates and between the bipolar plates and the membrane electrode, the opening of the second regulating valve is adjusted in step S2 so that the hydrogen leakage flow rate is 1.2 times the safety factor flow rate.

[0072] S3. Adjust the opening of the first regulating valve and the second regulating valve multiple times to simulate the fuel cell stack ventilation and purging flow rate under different hydrogen leakage amounts, and obtain the hydrogen concentration values ​​of the first hydrogen concentration sensor to the seventh hydrogen concentration sensor; preferably, in step S3, during the adjustment of the opening of the first regulating valve, the air velocity is always greater than 0.2m / s.

[0073] S4. Compare the hydrogen concentration values ​​from the first to the seventh hydrogen concentration sensors with the design values ​​to determine if all hydrogen concentration values ​​are less than or equal to the design value (target value). If so, the calibration is complete, and the fuel cell stack ventilation purging flow rate corresponding to the opening degree of the first regulating valve is output. Otherwise, repeat steps S3 to S4. Figure 3 As stated, but not limited to Figure 3 The content marked.

[0074] Preferably, the PACK incorporates multiple fuel cell stacks to be calibrated, in order to simulate a multi-stack fuel cell.

[0075] Preferably, the PACK is a built-in PACK for the fuel cell or a laboratory PACK simulator.

[0076] For fuel cells with their own PACK, the device also includes an auxiliary unit for drilling holes in the PACK to create a hydrogen leak inlet.

[0077] For a dual-stack fuel cell with one stack above the other, the first waterproof vent valve is located above the stack purge inlet, and the second waterproof vent valve is located above the stack purge outlet. The stack purge inlet and the stack purge outlet are located on opposite diagonals of the PACK housing.

[0078] Compared with the prior art, the fuel cell stack ventilation and purging flow calibration device provided in this embodiment has the following advantages:

[0079] 1. The ventilation flow calibration device takes into account the influence of multiple environmental factors on the encapsulated module, and the obtained ventilation purging flow results are more accurate and in line with reality compared with the existing technology.

[0080] 2. By simulating hydrogen leakage, the air inlet flow rate of the encapsulation module is accurately calibrated, minimizing the impact of hydrogen leakage on the performance of the fuel cell system and the power consumption of the air compressor, thereby improving the safety and reliability of the fuel cell system.

[0081] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to the prior art of the embodiments, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A device for calibrating the purge flow rate of a hydrogen fuel cell stack, characterized in that, It includes a PACK with a built-in fuel cell stack to be calibrated, a compressed air source, a compressed hydrogen source, a first regulating valve, a second regulating valve, a first flow meter, a second flow meter, and several hydrogen concentration sensors; The PACK housing is provided with a fuel cell purge inlet, a fuel cell purge outlet, and a hydrogen leak inlet; the fuel cell purge inlet is connected to a compressed air source via a first flow meter and a first regulating valve; the fuel cell purge outlet is connected to the outdoor area of ​​the calibration device; the hydrogen leak inlet is connected to a compressed hydrogen source via a second flow meter and a second regulating valve. The hydrogen leak inlet is located in the low-flow-rate area of ​​the PACK; hydrogen concentration sensors are located in multiple different locations within the PACK to measure the hydrogen concentration distribution within the PACK; low flow rate means that the gas flow rate in the area does not exceed 20% of the compressed air flow rate at the fuel cell purge inlet.

2. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to claim 1, characterized in that, It also includes an environmental simulation device; wherein the environmental simulation device further includes: The dry-wet cycle simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after repeated operation in dry and wet conditions; The acid environment simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in an acidic state. The air pressure fluctuation simulation unit is located indoors where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in an air pressure fluctuation environment.

3. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to claim 2, characterized in that, The environmental simulation device also includes: The high and low temperature environment simulation unit is located in the room where the PACK is located and is used to simulate the purging of the fuel cell stack after it has been operating in a high or low temperature environment.

4. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to any one of claims 1-3, characterized in that, It also includes a first temperature and pressure sensor and a second temperature and pressure sensor; wherein, the first temperature and pressure sensor is located at the front end of the fuel cell purge inlet, and the second temperature and pressure sensor is located at the front end of the hydrogen leak inlet; and... The PACK housing is also equipped with a first waterproof and breathable valve and a second waterproof and breathable valve; among which, The first waterproof vent valve is installed on the battery pack purge inlet side of the PACK, and the second waterproof vent valve is installed on the battery pack purge outlet side of the PACK. The two valves are used to balance the internal and external pressure of the PACK and prevent water and water vapor from entering the PACK. The hydrogen leak inlet is located on one side of the PACK's non-fuel pile purge inlet and fuel pile purge outlet.

5. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to claim 4, characterized in that, There are 7 hydrogen concentration sensors, namely: The first hydrogen concentration sensor is installed outside the first waterproof and breathable valve of the PACK. The second hydrogen concentration sensor is installed outside the second waterproof and breathable valve of the PACK. The third hydrogen concentration sensor is installed at the purge outlet of the fuel cell stack inside the PACK. The fourth, fifth, sixth, and seventh hydrogen concentration sensors are evenly distributed on the top of the PACK.

6. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to any one of claims 1, 2, 3, and 5, characterized in that, The hydrogen leak inlet is located at the bottom of the PACK.

7. The fuel cell stack ventilator purging flow rate calibration device for hydrogen fuel cells according to claim 5, characterized in that, It also includes a controller; the controller executes the following program to perform the calibration function of the fuel cell stack ventilation purging flow rate: S1. Start the first regulating valve and acquire data from the first flow meter and the first temperature and pressure sensor; S2. Start the second regulating valve and acquire data from the second flow meter and the second temperature and pressure sensor; S3. Adjust the opening of the first regulating valve and the second regulating valve multiple times to simulate the fuel cell stack ventilation and purging flow rate under different hydrogen leakage amounts, and obtain the hydrogen concentration values ​​from the first hydrogen concentration sensor to the seventh hydrogen concentration sensor. S4. Compare the hydrogen concentration values ​​of the first to seventh hydrogen concentration sensors with the design value to identify whether all hydrogen concentration values ​​are less than or equal to the design value. If so, end the calibration and output the fuel cell purge flow rate corresponding to the opening degree of the first regulating valve; otherwise, repeat steps S3 to S4.

8. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to claim 7, characterized in that, After activating the first regulating valve in step S1, the battery pack inside the PACK is purged with an air flow rate greater than 0.2 m / s; and, In step S2, the opening of the second regulating valve is adjusted so that the hydrogen leakage flow rate exceeds the design safe flow rate; In step S3, during the adjustment of the opening of the first regulating valve, the air velocity is always greater than 0.2 m / s.

9. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to claim 8, characterized in that, The PACK contains multiple fuel cell stacks to be calibrated in order to simulate multi-stack fuel cells.

10. The fuel cell stack ventilation and purging flow rate calibration device for hydrogen fuel cells according to claim 9, characterized in that, The PACK can be a fuel cell integrated PACK or a laboratory PACK simulator; for a fuel cell integrated PACK, the device also includes an auxiliary unit for drilling holes in the PACK to create a hydrogen leak inlet; and... For a dual-stack fuel cell with one stack above the other, the first waterproof vent valve is located above the stack purge inlet, and the second waterproof vent valve is located below the stack purge outlet. The stack purge inlet and the stack purge outlet are located on opposite diagonals of the PACK housing.

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