A method for calculating the sealing performance of a hydrogen fuel cell system

Abstract

The present application relates to a kind of sealing performance calculation method based on hydrogen fuel cell system.The present application records the temperature and pressure of hydrogen high-pressure buffer cavity, the temperature and pressure of fuel cell stack and ambient pressure respectively at the time when hydrogen fuel cell system executes shutdown process and the time when it executes start-up again, and calculates the total amount of gas mole stored in hydrogen fuel cell system.Then, the average value of ambient pressure at the two times, the difference value of total amount of gas mole and the time difference of hydrogen fuel cell system from the time when it executes shutdown process to the time when it executes start-up again are calculated, and finally the sealing performance value of hydrogen fuel cell system is calculated.Compared with prior art, the present application is based on hydrogen supply scheme after hydrogen fuel cell system shutdown, and proposes a kind of sealing performance calculation method of hydrogen fuel cell system, to help quantify the sealing performance of hydrogen fuel cell system to environment, so as to provide data support for regular maintenance of hydrogen fuel cell system.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen fuel cell technology, and in particular relates to a method for calculating the sealing performance of a hydrogen fuel cell system. Background Technology

[0002] Hydrogen proton exchange membrane fuel cells (HPEMFCs) are widely used in the transportation sector, especially in buses, logistics vehicles, and heavy-duty trucks, due to their advantages such as high efficiency, zero pollution, low operating temperature, and low noise. When a vehicle driver prepares to park the vehicle for an extended period, the onboard HPEMFC system must execute a series of shutdown operations according to the shutdown command. This ultimately ensures that the hydrogen chamber of the fuel cell stack is filled with hydrogen, and the oxygen in the air chamber is completely consumed. The hydrogen and air chambers of the fuel cell stack are in a hydrogen reducing atmosphere, ensuring that the catalyst inside the fuel cell stack is not oxidized by oxygen.

[0003] However, it is impossible to completely seal the hydrogen and air chambers of a fuel cell stack. Over time, oxygen from the air will inevitably seep into these chambers through weak points in the seal. When this oxygen reaches the vicinity of the catalyst inside the fuel cell stack, hydrogen and oxygen react, gradually consuming the hydrogen. After a sufficiently long period, the hydrogen in the hydrogen and air chambers is completely consumed, and oxygen gradually fills them. The catalyst inside the fuel cell stack is then exposed to an oxidizing oxygen atmosphere, leading to catalyst performance loss or catalyst runoff. The worse the sealing of the hydrogen and air chambers, the shorter the time it takes for them to transition from a hydrogen reducing atmosphere to an oxygen oxidizing atmosphere, and the greater the likelihood of catalyst oxidation and performance loss or runoff.

[0004] Currently, during the start-up or shutdown of a hydrogen fuel cell system, when the hydrogen chamber pressure of the fuel cell stack is established, the air chamber of the fuel cell stack is sealed, and the fuel cell stack is not outputting current, the sealing performance of the fuel cell stack is judged based on the change in hydrogen chamber pressure over time. However, the shutdown and start-up processes of a hydrogen fuel cell system are very short. The fuel cell stack sealing performance judged by the change in hydrogen chamber pressure over time is only a comprehensive assessment of the sealing performance of the fuel cell stack against hydrogen-air leakage and hydrogen-water leakage, and not an assessment of the fuel cell system's environmental sealing performance.

[0005] Therefore, based on the hydrogen supply scheme after the hydrogen fuel cell system is shut down, it is necessary to propose a method for calculating the sealing performance of the hydrogen fuel cell system to help quantify the environmental sealing performance of the hydrogen fuel cell system, thereby providing data support for the regular maintenance of the hydrogen fuel cell system. Summary of the Invention

[0006] The purpose of this invention is to provide a method for calculating the sealing performance of a hydrogen fuel cell system to help quantify the environmental sealing performance of the hydrogen fuel cell system.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for calculating the sealing performance of a hydrogen fuel cell system, wherein the hydrogen fuel cell system includes a control system and a hydrogen high-pressure buffer chamber, a hydrogen supply module after shutdown, and a fuel cell stack connected in sequence by pipelines.

[0009] Furthermore, the fuel cell stack includes a fuel cell stack hydrogen chamber and a fuel cell stack air chamber separated by a membrane electrode assembly.

[0010] The method for calculating the sealing performance of a hydrogen fuel cell system includes the following steps:

[0011] S1: At the moment when the shutdown process of the hydrogen fuel cell system ends, record the temperature and pressure of the high-pressure buffer chamber of hydrogen, the temperature and pressure of the fuel cell stack, and the temperature and pressure of the environment, and calculate the total amount of gas moles stored in the hydrogen fuel cell system at this time based on the above data.

[0012] S2: When the hydrogen fuel cell system restarts, record the temperature and pressure of the high-pressure buffer chamber, the temperature and pressure of the fuel cell stack, and the ambient temperature and pressure, and calculate the total amount of gas moles stored in the hydrogen fuel cell system at this time based on the above data.

[0013] S3: Calculate the average ambient pressure PEN, the difference in total gas molars NGAS, and the time difference t from the end of the shutdown process to the restart of the hydrogen fuel cell system in S1 and S2 respectively. Based on the pressure PLP0 of the fuel cell stack in S1, the sealing performance value of the hydrogen fuel cell system within the time difference t is finally calculated as NGAS / t / (PLP0-PEN), with the unit being mol / (s·Pa).

[0014] Furthermore, a high-pressure hydrogen temperature sensor and a high-pressure hydrogen pressure sensor are installed on the high-pressure hydrogen buffer cavity, and the high-pressure hydrogen temperature sensor and the high-pressure hydrogen pressure sensor are electrically connected to the control system respectively.

[0015] Further, in step S1, the high-pressure hydrogen temperature value THP0 of the high-pressure hydrogen temperature sensor and the high-pressure hydrogen pressure value PHP0 of the high-pressure hydrogen pressure sensor are recorded respectively.

[0016] Further, in step S2, the high-pressure hydrogen temperature value THP1 of the high-pressure hydrogen temperature sensor and the high-pressure hydrogen pressure value PHP1 of the high-pressure hydrogen pressure sensor are recorded respectively.

[0017] Furthermore, a fuel cell stack temperature sensor is installed on the fuel cell stack, and the fuel cell stack temperature sensor is electrically connected to the control system.

[0018] Further, in steps S1 and S2, the fuel cell stack temperatures TSK0 and TSK1 of the fuel cell stack temperature sensor are recorded respectively.

[0019] Furthermore, a hydrogen pressure sensor is installed at the inlet of the hydrogen chamber of the fuel cell stack, and an air pressure sensor is installed on the air chamber of the fuel cell stack. The hydrogen pressure sensor and the air pressure sensor are electrically connected to the control system.

[0020] Further, in step S1, the hydrogen pressure PLPH0 of the hydrogen pressure sensor and the air pressure PLPA0 of the air pressure sensor are recorded respectively.

[0021] Further, in step S2, the hydrogen pressure PLPH1 of the hydrogen pressure sensor and the air pressure PLPA1 of the air pressure sensor are recorded respectively.

[0022] Further, in step S3, PLP0 is selected from PLPH0, PLPA0, or the average value of PLPH0 and PLPA0.

[0023] Furthermore, the control system is electrically connected to an ambient temperature sensor and an ambient pressure sensor, respectively.

[0024] Further, in step S1, the ambient temperature TEN0 of the ambient temperature sensor and the ambient pressure PEN0 of the ambient pressure sensor are recorded respectively.

[0025] Further, in step S2, the ambient temperature TEN1 of the ambient temperature sensor and the ambient pressure PEN1 of the ambient pressure sensor are recorded respectively.

[0026] Furthermore, the hydrogen fuel cell system also includes a shut-off valve, a hydrogen injection valve assembly, a hydrogen circulation pump, a water distribution module, and a tailpipe valve, which are electrically connected to the control system.

[0027] Furthermore, the shut-off valve is located before the inlet of the hydrogen high-pressure buffer chamber, and can open or close the hydrogen supply.

[0028] Furthermore, the hydrogen injection valve assembly is connected to the outlet of the hydrogen high-pressure buffer chamber.

[0029] Furthermore, the hydrogen circulation pump, fuel cell stack, and water distribution module are connected in sequence to form a circulation system.

[0030] Furthermore, the tail valve is connected to the outlet of the water distribution module, which can discharge the liquid water and gas stored in the water distribution module from the water distribution module.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) This invention provides a method for calculating the sealing performance of a hydrogen fuel cell system. By measuring the temperature and pressure of hydrogen and air during the short time difference between the shutdown and startup processes of the hydrogen fuel cell system, the sealing performance of the hydrogen fuel cell system to the environment is quantified, thereby providing data support for the regular maintenance of the hydrogen fuel cell system.

[0033] (2) This invention can quantitatively evaluate the sealing performance of a fuel cell system to the external environment, rather than just evaluating the combined sealing performance of hydrogen-air leakage and hydrogen-water leakage of the fuel cell stack, thus expanding the evaluation method for the sealing performance of hydrogen fuel cell systems. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the sealing performance calculation method of the present invention.

[0035] Figure 2 This is a schematic diagram of the hydrogen fuel cell system in Example 2.

[0036] Explanation of markings in the diagram:

[0037] 1-Control system; 2-High-pressure hydrogen buffer chamber; 3-Hydrogen supply module after shutdown; 4-Fuel cell stack; 5-Hydrogen chamber of fuel cell stack; 6-Air chamber of fuel cell stack; 7-High-pressure hydrogen temperature sensor; 8-High-pressure hydrogen pressure sensor; 9-Fuel cell stack temperature sensor; 10-Hydrogen pressure sensor; 11-Air pressure sensor; 12-Ambient temperature sensor; 13-Ambient pressure sensor; 14-Stop valve; 15-Hydrogen injection valve assembly; 16-Hydrogen circulation pump; 17-Water distribution module; 18-Tail exhaust valve. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0039] Example 1:

[0040] This embodiment provides a method for calculating the sealing performance of a hydrogen fuel cell system. The hydrogen fuel cell system of this embodiment includes a control system 1 and, in sequence via pipelines, a high-pressure hydrogen buffer chamber 2, a hydrogen supply module 3 after shutdown, and a fuel cell stack 4. A high-pressure hydrogen temperature sensor 7 and a high-pressure hydrogen pressure sensor 8 are installed on the high-pressure hydrogen buffer chamber 2, and the high-pressure hydrogen temperature sensor 7 and the high-pressure hydrogen pressure sensor 8 are electrically connected to the control system 1.

[0041] The fuel cell stack 4 is divided into a hydrogen gas chamber 5 and an air chamber 6 by a membrane electrode assembly (MEA). A fuel cell stack temperature sensor 9 is installed on the fuel cell stack and is electrically connected to the control system 1. A hydrogen pressure sensor 10 is installed at the inlet of the hydrogen gas chamber 5, and an air pressure sensor 11 is installed on the air chamber 6. Both the hydrogen pressure sensor 10 and the air pressure sensor 11 are electrically connected to the control system 1. Furthermore, the control system 1 is electrically connected to an ambient temperature sensor 12 and an ambient pressure sensor 13.

[0042] In this embodiment, the method for calculating the sealing performance of the hydrogen fuel cell system is as follows: Figure 1 As shown, it includes the following steps:

[0043] S1: At the moment when the shutdown process of the hydrogen fuel cell system ends, record the temperature and pressure of the hydrogen high-pressure buffer chamber 2, the temperature and pressure of the fuel cell stack 4, and the ambient pressure, and calculate the total amount of gas moles stored in the hydrogen fuel cell system at this time based on the above data.

[0044] S2: When the hydrogen fuel cell system restarts, record the temperature and pressure of the high-pressure buffer chamber 2, the temperature and pressure of the fuel cell stack 4, and the ambient pressure, and calculate the total amount of gas moles stored in the hydrogen fuel cell system at this time based on the above data.

[0045] S3: Calculate the average ambient pressure PEN, the difference in total gas molars NGAS, and the time difference t from the end of the shutdown process to the restart of the hydrogen fuel cell system in S1 and S2 respectively. Based on the pressure PLP0 of the fuel cell stack in S1, the sealing performance value of the hydrogen fuel cell system within the time difference t is finally calculated as NGAS / t / (PLP0-PEN), with the unit being mol / (s·Pa).

[0046] Specifically, in step S1, the high-pressure hydrogen temperature value THP0 of the high-pressure hydrogen temperature sensor 7, the high-pressure hydrogen pressure value PHP0 of the high-pressure hydrogen pressure sensor 8, the fuel cell stack temperature TSK0 of the fuel cell stack temperature sensor 9, the hydrogen pressure PLPH0 of the hydrogen pressure sensor 10, the air pressure PLPA0 of the air pressure sensor 11, the ambient temperature TEN0 of the ambient temperature sensor 12, and the ambient pressure PEN0 of the ambient pressure sensor 13 are recorded respectively.

[0047] Specifically, in step S2, the high-pressure hydrogen temperature value THP1 of the high-pressure hydrogen temperature sensor 7, the high-pressure hydrogen pressure value PHP1 of the high-pressure hydrogen pressure sensor 8, the fuel cell stack temperature TSK1 of the fuel cell stack temperature sensor 9, the hydrogen pressure PLPH1 of the hydrogen pressure sensor 10, the air pressure PLPA1 of the air pressure sensor 11, the ambient temperature TEN1 of the ambient temperature sensor 12, and the ambient pressure PEN1 of the ambient pressure sensor 13 are recorded respectively.

[0048] Specifically, in step S3, PLP0 is selected from PLPH0, PLPA0, or the average value of PLPH0 and PLPA0.

[0049] Example 2:

[0050] The hydrogen supply device of the hydrogen fuel cell system in this embodiment is as follows: Figure 2 As shown, the system comprises a control system 1, a high-pressure hydrogen buffer chamber 2, a hydrogen injection valve assembly 15, a post-shutdown hydrogen supply module 3, a hydrogen circulation pump 16, a fuel cell stack hydrogen chamber 5, a water distribution module 17, a fuel cell stack air chamber 6, a shut-off valve 14, a tailpipe valve 18, a high-pressure hydrogen temperature sensor 7, a high-pressure hydrogen pressure sensor 8, a hydrogen pressure sensor 10, a fuel cell stack temperature sensor 9, an air pressure sensor 11, an ambient temperature sensor 12, and an ambient pressure sensor 13. In this embodiment, the post-shutdown hydrogen supply module 3 includes a pressure reducing valve that can control its opening and closing, enabling the delivery of hydrogen from the high-pressure hydrogen buffer chamber 2 into the fuel cell stack hydrogen chamber 5 after the hydrogen fuel cell system shuts down. The water distribution module 17 in this embodiment is a water separator for collecting and separating moisture. The control system 1 in this embodiment is a commercial fuel cell control system.

[0051] The inlet of shut-off valve 14 is connected to the hydrogen supply source via a pipeline interface, and the outlet of shut-off valve 14 is connected to the inlet of hydrogen high-pressure buffer chamber 2 via a pipeline interface. The outlet of hydrogen high-pressure buffer chamber 2 is connected to the inlet of hydrogen injection valve assembly 15 via a pipeline interface, and the outlet of hydrogen high-pressure buffer chamber 2 is connected to the inlet of the hydrogen supply module after shutdown via a pipeline interface. Hydrogen high-pressure buffer chamber 2 is equipped with a high-pressure hydrogen temperature sensor 7 for measuring the hydrogen temperature inside hydrogen high-pressure buffer chamber 2, and a high-pressure hydrogen pressure sensor 8 for measuring the hydrogen pressure inside hydrogen high-pressure buffer chamber 2.

[0052] The outlet of the hydrogen circulation pump 16, the outlet of the hydrogen injection valve assembly 15, the outlet of the hydrogen pressure reducing valve, and the inlet of the hydrogen chamber 5 of the fuel cell stack are connected via a pipeline interface. The inlet of the hydrogen chamber 5 of the fuel cell stack is equipped with a hydrogen pressure sensor 10 for measuring the hydrogen pressure at the inlet of the hydrogen chamber 5 of the fuel cell stack.

[0053] The outlet of the hydrogen chamber 5 in the fuel cell stack is connected to the inlet of the water distribution module 17 via a pipeline interface. The outlet of the water distribution module 17 is also connected to the inlet of the exhaust valve 18 via a pipeline interface. The outlet of the water distribution module 17 is connected to the inlet of the hydrogen circulation pump 16 via a pipeline interface. The outlet pipeline of the exhaust valve 18 is connected to other components of the hydrogen fuel cell system. The hydrogen chamber 5 and the air chamber 6 of the fuel cell stack are physically separated by a membrane electrode assembly (MEA). The MEA is not a strictly dense object; hydrogen, nitrogen, water vapor, oxygen, and liquid water can all be transported between the hydrogen chamber 5 and the air chamber 6 through the MEA.

[0054] The fuel cell stack 4, which consists of the hydrogen gas chamber 5 and the air chamber 6 of the fuel cell stack, is equipped with a fuel cell stack temperature sensor 9 for measuring the temperature of the fuel cell stack; the fuel cell stack air chamber 6 is equipped with an air pressure sensor 11 for measuring the pressure of the fuel cell stack air chamber 6.

[0055] The control system 1 is electrically connected via wiring harness to the shut-off valve 14, hydrogen injection valve assembly 15, hydrogen circulation pump 16, exhaust valve 18, high-pressure hydrogen temperature sensor 7, high-pressure hydrogen pressure sensor 8, hydrogen pressure sensor 10, fuel cell stack temperature sensor 9, and air pressure sensor 11. The control system 1 regulates the operation of the shut-off valve 14, hydrogen injection valve assembly 15, hydrogen circulation pump 16, and exhaust valve 18. Furthermore, the control system 1 is also electrically connected via wiring harness to an ambient temperature sensor 12 for measuring ambient temperature and an ambient pressure sensor 13 for measuring ambient pressure.

[0056] The operating mode of the hydrogen supply device in the hydrogen fuel cell system of this embodiment is as follows:

[0057] 1. Normal Operation and Shutdown Modes of the Hydrogen Fuel Cell System: Control system 1 regulates shut-off valve 14 to keep it in the open state, ensuring a continuous flow of hydrogen from the hydrogen supply source into the high-pressure buffer chamber 2. Control system 1 regulates the switching cycle and opening time of the electronically controlled nozzles in the hydrogen injection valve assembly 15 to ensure that the inlet pressure of the hydrogen chamber 5 of the fuel cell stack meets the hydrogen reaction requirements of the fuel cell stack. Control system 1 regulates the speed of the hydrogen circulation pump 16 to increase the outlet gas pressure of the hydrogen chamber 5 of the fuel cell stack and resupply it into the inlet of the hydrogen chamber 5. Control system 1 also regulates the switching cycle and opening time of the tail valve 18 to discharge the liquid water and gas stored in the water distribution module 17. During this period, the hydrogen supply module 3 does not operate after shutdown, preventing hydrogen from entering the hydrogen chamber 5 of the fuel cell stack from the high-pressure buffer chamber 2 via the shutdown hydrogen supply module 3.

[0058] 2. Operating mode after hydrogen fuel cell system shutdown: The shut-off valve 14 is in the closed state, cutting off the gas flow between the hydrogen supply source and the high-pressure hydrogen buffer chamber 2. The hydrogen injection valve assembly 15 is in the closed state, cutting off the path of hydrogen from the high-pressure hydrogen buffer chamber 2 into the hydrogen chamber 5 of the fuel cell stack. The hydrogen circulation pump 16 is in the stopped state. The tailpipe valve 18 is in the closed state, cutting off the gas flow between the water distribution module 17 and the outside environment. The high-pressure hydrogen buffer chamber 2 stores hydrogen at a certain pressure and mass.

[0059] When oxygen from the air gradually permeates into the fuel cell stack through the weak points in the seals of the hydrogen chamber 5 and air chamber 6, and as the oxygen permeates to the vicinity of the catalyst inside the fuel cell stack and reacts with the hydrogen, gradually consuming the hydrogen, the pressure in the hydrogen chamber 5 and air chamber 6 will continuously decrease over time until the hydrogen is completely consumed. During this period, after shutdown, the hydrogen supply module 3 operates intermittently or continuously, allowing hydrogen to flow intermittently or continuously from the high-pressure buffer chamber 2 through the shutdown hydrogen supply module 3 into the hydrogen chamber 5 of the fuel cell stack via the mechanical opening and closing of the hydrogen pressure reducing valve.

[0060] Based on the hydrogen supply device of the hydrogen fuel cell system described above, the specific method for calculating the sealing performance of the hydrogen fuel cell system in this embodiment is as follows:

[0061] Step S1:

[0062] At the moment when the shutdown process of the hydrogen fuel cell system ends, the following values ​​are recorded: high-pressure hydrogen temperature value THP0 of high-pressure hydrogen temperature sensor 7 in hydrogen high-pressure buffer chamber 2; high-pressure hydrogen pressure value PHP0 of high-pressure hydrogen pressure sensor 8 in hydrogen high-pressure buffer chamber 2; fuel cell stack temperature TSK0 of fuel cell stack temperature sensor 9; hydrogen pressure PLPH0 of hydrogen pressure sensor 10; air pressure PLPA0 of air pressure sensor 11; local time t0 at the end of the current shutdown process of the hydrogen fuel cell system (which can be obtained by synchronizing time with a remote data center; currently, hydrogen fuel cell systems are equipped with cloud platform data communication equipment); ambient temperature TEN0 of ambient temperature sensor 12; and ambient pressure PEN0 of ambient pressure sensor 13.

[0063] Given that the volume of the hydrogen high-pressure buffer chamber 2 is VHP, the volume of the hydrogen chamber 5 of the fuel cell stack is VLPH, the volume of the air chamber 6 of the fuel cell stack is VLPA, and the general gas constant is R.

[0064] The calculation process is as follows: Calculate the amount of hydrogen stored in the high-pressure buffer chamber 2 as VHP*PHP0 / (R*THP0); calculate the amount of gas stored in the hydrogen chamber of the fuel cell stack as VLPH*PLPH0 / (R*TSK0); calculate the amount of gas stored in the air chamber of the fuel cell stack as VLPA*PLPA0 / (R*TSK0); calculate the total amount of gas stored in the hydrogen fuel cell system at this time as NGAS0=VHP*PHP0 / (R*THP0)+(VLPH*PLPH0+VLPA*PLPA0) / (R*TSK0).

[0065] Step S2:

[0066] At the moment when the hydrogen fuel cell system restarts, the following values ​​are recorded: the high-pressure hydrogen temperature value THP1 of the high-pressure hydrogen temperature sensor 7 in the high-pressure hydrogen buffer chamber 2; the high-pressure hydrogen pressure value PHP1 of the high-pressure hydrogen pressure sensor 8 in the high-pressure hydrogen buffer chamber 2; the fuel cell stack temperature TSK1 of the fuel cell stack temperature sensor 9; the hydrogen pressure PLPH1 of the hydrogen pressure sensor 10; the air pressure PLPA1 of the air pressure sensor 11; the local time t1 at the end of the current hydrogen fuel cell system shutdown process (which can be obtained by synchronizing time with a remote data center; currently, hydrogen fuel cell systems are all equipped with cloud platform data communication equipment); the ambient temperature TEN1 of the ambient temperature sensor 12; and the ambient pressure PEN1 of the ambient pressure sensor 13.

[0067] The calculation process is as follows: Calculate the amount of hydrogen stored in the high-pressure buffer chamber as VHP*PHP1 / (R*THP1); calculate the amount of gas stored in the hydrogen chamber of the fuel cell stack as VLPH*PLPH1 / (R*TSK1); calculate the amount of gas stored in the air chamber of the fuel cell stack as VLPA*PLPA1 / (R*TSK1); calculate the total amount of gas stored in the hydrogen fuel cell system at this time as NGAS1=VHP*PHP1 / (R*THP1)+(VLPH*PLPH1+VLPA*PLPA1) / (R*TSK1).

[0068] Step S3: Calculate the average value of the ambient temperature TEN0 at the end of the previous shutdown process of the hydrogen fuel cell system and the ambient temperature TEN1 at the start-up time of the current hydrogen fuel cell system: TEN = (TEN0 + TEN1) / 2. TEN is the data that must be collected throughout the entire life cycle of the hydrogen fuel cell system for necessary correlation analysis between sealing performance and ambient temperature (must be linear or nonlinear correlation). Calculate the average value of the ambient pressure PEN0 at the end of the previous shutdown process and the ambient pressure PEN1 at the start-up time of the current hydrogen fuel cell system: PEN = (PEN0 + PEN1) / 2. Calculate the difference between the total gas molar amount NGAS0 at the end of the previous shutdown process and NGAS1 at the start-up time of the current hydrogen fuel cell system: NGAS = NGAS0 - NGAS1. Calculate the difference between the local time t0 at the end of the previous shutdown process and the local time t1 at the start-up time of the current hydrogen fuel cell system: t = t1 - t0. Finally, the sealing performance value of the hydrogen fuel cell system is calculated as NGAS / t / (PLP0-PEN) over the entire time period from the end of the previous shutdown process to the start-up process, in mol / (Pa·s). Here, PLP0 can be taken as the hydrogen pressure PLPH0 of the hydrogen pressure sensor at the end of the previous shutdown process, or the air pressure PLPA0 of the air pressure sensor at the end of the previous shutdown process, or the average of the hydrogen pressure PLPH0 and air pressure PLPA0 of the air pressure sensor at the end of the previous shutdown process. A lower sealing performance value indicates better sealing performance of the hydrogen fuel cell system.

[0069] 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 calculating the sealing performance of a hydrogen fuel cell system, characterized in that, The hydrogen fuel cell system includes a control system and a hydrogen high-pressure buffer chamber, a hydrogen supply module after shutdown, and a fuel cell stack connected in sequence by pipelines. The fuel cell stack includes a fuel cell stack hydrogen chamber and a fuel cell stack air chamber separated by membrane electrode assemblies. The method for calculating the sealing performance of a hydrogen fuel cell system includes the following steps: Step S1: At the end of the shutdown process of the hydrogen fuel cell system, record the following values: high-pressure hydrogen temperature value THP0 of the high-pressure hydrogen temperature sensor in the high-pressure hydrogen buffer chamber; high-pressure hydrogen pressure value PHP0 of the high-pressure hydrogen pressure sensor in the high-pressure hydrogen buffer chamber; fuel cell stack temperature TSK0 of the fuel cell stack temperature sensor; hydrogen pressure PLPH0 of the hydrogen pressure sensor; air pressure PLPA0 of the air pressure sensor; ambient temperature TEN0 of the ambient temperature sensor; ambient pressure PEN0 of the ambient pressure sensor. Given that the volume of the hydrogen high-pressure buffer chamber is VHP, the volume of the hydrogen chamber in the fuel cell stack is VLPH, the volume of the air chamber in the fuel cell stack is VLPA, and the general gas constant is R. The calculation process is as follows: Calculate the molar amount of hydrogen stored in the high-pressure buffer chamber as VHP*PHP0 / (R*THP0); calculate the molar amount of gas stored in the hydrogen chamber of the fuel cell stack as VLPH*PLPH0 / (R*TSK0); calculate the molar amount of gas stored in the air chamber of the fuel cell stack as VLPA*PLPA0 / (R*TSK0); calculate the total molar amount of gas stored in the hydrogen fuel cell system at this time as NGAS0=VHP*PHP0 / (R*THP0)+(VLPH*PLPH0+VLPA*PLPA0) / (R*TSK0); Step S2: When the hydrogen fuel cell system restarts, record the following values: high-pressure hydrogen temperature (THP1) of the high-pressure hydrogen temperature sensor in the high-pressure hydrogen buffer chamber; high-pressure hydrogen pressure (PHP1) of the high-pressure hydrogen pressure sensor in the high-pressure hydrogen buffer chamber; fuel cell stack temperature (TSK1) of the fuel cell stack temperature sensor; hydrogen pressure (PLPH1) of the hydrogen pressure sensor; air pressure (PLPA1) of the air pressure sensor; ambient temperature (TEN1) of the ambient temperature sensor; and ambient pressure (PEN1) of the ambient pressure sensor. The calculation process is as follows: Calculate the molar amount of hydrogen stored in the high-pressure buffer chamber as VHP*PHP1 / (R*THP1); calculate the molar amount of gas stored in the hydrogen chamber of the fuel cell stack as VLPH*PLPH1 / (R*TSK1); calculate the molar amount of gas stored in the air chamber of the fuel cell stack as VLPA*PLPA1 / (R*TSK1); calculate the total molar amount of gas stored in the hydrogen fuel cell system at this time as NGAS1=VHP*PHP1 / (R*THP1)+(VLPH*PLPH1+VLPA*PLPA1) / (R*TSK1); Step S3: Calculate the average value of the ambient pressure PEN0 at the end of the previous shutdown process of the hydrogen fuel cell system and the ambient pressure PEN1 at the start-up time of the current hydrogen fuel cell system: PEN = (PEN0 + PEN1) / 2; calculate the difference between the total gas molars NGAS0 at the end of the previous shutdown process and NGAS1 at the start-up time of the current hydrogen fuel cell system: NGAS = NGAS0 - NGAS1; calculate the difference between the local time t0 at the end of the previous shutdown process and t1 at the start-up time of the current hydrogen fuel cell system: t = t1 - t0; calculate the sealing performance value of the hydrogen fuel cell system during the entire time period from the end of the previous shutdown process to the start-up time of the current hydrogen fuel cell system: NGAS / t / (PLP0 - PEN), in mol / (Pa·s); Wherein, PLP0 is the hydrogen pressure PLPH0 of the hydrogen pressure sensor at the end of the last time the hydrogen fuel cell system executed a shutdown process, or the air pressure PLPA0 of the air pressure sensor at the end of the last time the hydrogen fuel cell system executed a shutdown process, or the average value of the hydrogen pressure PLPH0 of the hydrogen pressure sensor and the air pressure PLPA0 of the air pressure sensor at the end of the last time the hydrogen fuel cell system executed a shutdown process.

2. The method for calculating the sealing performance of a hydrogen fuel cell system according to claim 1, characterized in that, The high-pressure hydrogen buffer cavity is equipped with a high-pressure hydrogen temperature sensor and a high-pressure hydrogen pressure sensor, which are electrically connected to the control system.

3. The method for calculating the sealing performance of a hydrogen fuel cell system according to claim 1, characterized in that, A fuel cell stack temperature sensor is installed on the fuel cell stack, and the fuel cell stack temperature sensor is electrically connected to the control system.

4. The method for calculating the sealing performance of a hydrogen fuel cell system according to claim 1, characterized in that, A hydrogen pressure sensor is installed at the inlet of the hydrogen chamber of the fuel cell stack, and an air pressure sensor is installed on the air chamber of the fuel cell stack. The hydrogen pressure sensor and the air pressure sensor are electrically connected to the control system.

5. The method for calculating the sealing performance of a hydrogen fuel cell system according to claim 1, characterized in that, The control system is electrically connected to the ambient temperature sensor and the ambient pressure sensor, respectively.

6. The method for calculating the sealing performance of a hydrogen fuel cell system according to claim 1, characterized in that, The hydrogen fuel cell system also includes a shut-off valve, a hydrogen injection valve assembly, a hydrogen circulation pump, a water distribution module, and a tailpipe valve. The shut-off valve, hydrogen injection valve assembly, hydrogen circulation pump, and tailpipe valve are electrically connected to the control system.

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