Device for improving fuel cell stack performance and operation method thereof

Abstract

The invention relates to a device for improving fuel cell stack performance and an operation method thereof. The device comprises a fuel cell stack, a pressurizing cavity, an air supply pipeline, an air exhaust pipeline, an air stop valve, an air pressure reducing valve, a nitrogen supply pipeline, a nitrogen stop valve, a nitrogen pressure reducing valve, a hydrogen supply pipeline, a hydrogen exhaust pipeline, a hydrogen stop valve, a hydrogen pressure reducing valve, an air-nitrogen stop valve, a hydrogen-nitrogen stop valve and an air back pressure valve, and a hydrogen back pressure valve and a box body. The pressurizing cavity is filled with nitrogen with a certain pressure to balance the pressure of high-pressure air and hydrogen in the stack, so that the stable operation of a conventional stack under a high-pressure condition is met, and the damage of internal high pressure to the fuel cell stack is avoided. By increasing the pressure of air and hydrogen on the two sides of the membrane electrode, the oxygen partial pressure and diffusion efficiency are improved, the hydrogen storage pressure is adapted to fully convert the hydrogen pressure energy into electric energy, and the power density and efficiency of the fuel cell are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell performance optimization, and in particular to a device for improving the performance of a fuel cell stack and an operating method thereof. Background Art

[0002] In the fuel cell stack, the efficient transmission of O2 is a key factor affecting the battery performance. However, due to the low partial pressure and low diffusion efficiency of O2 in the air, the power and efficiency of the fuel cell are limited to a certain extent.

[0003] In order to maintain the necessary oxygen concentration on the membrane electrode, excess air is often introduced into the fuel cell stack to thin the O2 diffusion boundary layer. However, excessive compressed air will cause multiple negative effects: 1. It consumes additional compression work and reduces the net output power of the fuel cell; 2. The air flow rate in the flow channel is fast and the resistance is increased, which not only further increases the pressure work consumption, but also aggravates the inconsistency of the fuel cell; 3. Excessive air intensifies the evaporation of water in the fuel cell proton membrane, causing dryness, making it difficult to manage the water of the fuel cell.

[0004] By increasing the air pressure, the O2 partial pressure and O2 diffusion efficiency can be increased, thereby reducing air consumption and avoiding the side effects of excess air. In addition, the fuel cell performance can be improved in several key aspects: 1. Increasing the air pressure in the stack can balance the higher hydrogen pressure and convert it into electrical energy, increasing the output voltage, power and efficiency of the fuel cell; 2. Pressurization can not only improve the performance of the battery, but also enhance the stability and operating range of the system. For example, high pressure can improve the battery's resistance to gas impurities and temperature changes.

[0005] However, when the internal pressure of the fuel cell stack is too high, higher requirements will be placed on its mechanical properties, otherwise dangerous accidents such as leakage or even explosion will occur. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a device for improving the performance of a fuel cell stack and an operating method thereof, which can effectively avoid accidents such as mechanical fatigue, damage and leakage that may occur when a conventional fuel cell stack operates at high voltage.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A device for improving the performance of a fuel cell stack proposed in the present invention comprises a fuel cell stack, an air supply pipeline, an air exhaust pipeline, an air stop valve, an air pressure reducing valve, a nitrogen supply pipeline, a nitrogen stop valve, a nitrogen pressure reducing valve, a hydrogen supply pipeline, a hydrogen exhaust pipeline, a hydrogen stop valve, a hydrogen pressure reducing valve, an air-nitrogen stop valve, a hydrogen-nitrogen stop valve, an air back pressure valve, a hydrogen back pressure valve and a box body;

[0009] The box body is a closed structure, and a pressurized chamber is formed inside; the fuel cell stack is arranged in the pressurized chamber inside the box body; an air supply pipeline, a nitrogen supply pipeline and a hydrogen supply pipeline are sequentially arranged on one side of the box body, and the inner end of the air supply pipeline is connected to the air intake pipeline of the fuel cell stack; the inner end of the nitrogen supply pipeline is connected to the pressurized chamber; the inner end of the hydrogen supply pipeline is connected to the hydrogen intake pipeline of the fuel cell stack; an air exhaust pipeline and a hydrogen exhaust pipeline are sequentially arranged on the other side of the box body; the inner end of the air exhaust pipeline is connected to the air outlet pipeline of the fuel cell stack; the inner end of the hydrogen exhaust pipeline is connected to the hydrogen outlet pipeline of the fuel cell stack;

[0010] An air pressure reducing valve and an air shut-off valve are sequentially installed at the outer end of the air supply pipeline; a nitrogen pressure reducing valve and a nitrogen shut-off valve are sequentially installed at the outer end of the nitrogen supply pipeline; a hydrogen pressure reducing valve and a hydrogen shut-off valve are sequentially installed at the outer end of the hydrogen supply pipeline; the air supply pipeline is connected to the nitrogen supply pipeline through an air-nitrogen shut-off valve; the nitrogen supply pipeline is connected to the hydrogen supply pipeline through a hydrogen-nitrogen shut-off valve; an air back-pressure valve is installed at the outer end of the air exhaust pipeline; and a hydrogen back-pressure valve is installed at the outer end of the hydrogen exhaust pipeline.

[0011] Furthermore, a cooling water supply pipeline and a cooling water return pipeline are respectively provided on one side of the box body; the inner ends of the cooling water supply pipeline and the cooling water return pipeline respectively pass through the pressurized cavity wall of the box body and are connected to the cooling system of the fuel cell stack; a cooling water stop valve is installed at the outer end of the cooling water supply pipeline; and a cooling water back-pressure valve is installed at the outer end of the cooling water return pipeline.

[0012] Furthermore, a pressure relief pipeline is provided on one side of the box body; the inner end of the pressure relief pipeline is connected to the pressurized chamber inside the box body, and a pressure relief valve is installed on the outer end.

[0013] Furthermore, a hydrogen circulation pipeline is provided in the pressurized chamber inside the box; one end of the hydrogen circulation pipeline is connected to the hydrogen supply pipeline, and the other end is connected to the hydrogen exhaust pipeline, and a hydrogen circulation pump is installed in the middle of the hydrogen circulation pipeline.

[0014] Furthermore, the upper cover of the box body is fixedly connected to the top of the side wall by means of a buckle lock.

[0015] A method for operating a device for improving the performance of a fuel cell stack, the method comprising the following steps:

[0016] S1. Before the fuel cell is operated, the air shut-off valve and the hydrogen shut-off valve are in a closed state; the air back pressure valve, the hydrogen back pressure valve and the pressure relief valve are adjusted to the same high pressure;

[0017] S2. Adjust the pressure of the nitrogen pressure reducing valve to be slightly higher than that of the pressure relief valve, hydrogen back pressure valve, and air back pressure valve, slightly open the nitrogen stop valve, fully open the nitrogen-air stop valve and the nitrogen-hydrogen stop valve, and inject nitrogen into the pressurization chamber, air supply pipeline, and hydrogen supply pipeline at the same time, and continue to increase the pressure to remove the residual gas inside the pressurization chamber and the fuel cell stack;

[0018] S3, after step S2, a certain pressure has been established inside the pressurized chamber and the fuel cell stack, the nitrogen-air shut-off valve and the nitrogen-hydrogen shut-off valve are closed, the air pressure reducing valve and the hydrogen pressure reducing valve are adjusted to the same state as the nitrogen pressure reducing valve, and the air shut-off valve and the hydrogen shut-off valve are opened to supply high-pressure air and hydrogen to the air supply pipeline and the hydrogen supply pipeline respectively, and the fuel cell starts to operate;

[0019] S4. During the operation of the fuel cell, the exhaust gas is discharged from the air back pressure valve and the hydrogen back pressure valve respectively, and the high-pressure nitrogen is continuously supplied to the pressurization chamber at a low flow rate through the nitrogen pressure reducing valve and the nitrogen stop valve to dilute the trace hydrogen and air leaked from the fuel cell stack and discharged from the pressure relief valve;

[0020] S5. After the fuel cell operation is finished, close the air shut-off valve and the hydrogen shut-off valve, and open the nitrogen-air shut-off valve and the nitrogen-hydrogen shut-off valve, and continue to supply nitrogen to the pressurized chamber and the fuel cell stack to purge the residual gas;

[0021] S6. After completing the residual gas purging, close the nitrogen shut-off valve and stop supplying high-pressure nitrogen.

[0022] Furthermore, in the shutdown state, a certain pressure of nitrogen is maintained inside the pressurized chamber and the fuel cell stack.

[0023] Furthermore, if it is necessary to open the pressurized chamber, first close the air shut-off valve, nitrogen shut-off valve, and hydrogen shut-off valve, open the nitrogen-air shut-off valve and the nitrogen-hydrogen shut-off valve, and slowly adjust the pressure relief valve to discharge the high-pressure nitrogen in the pressurized chamber and the fuel cell stack to achieve balance with the atmospheric pressure, then open the buckle on the box and remove the upper cover.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention increases the pressure of air and hydrogen on both sides of the membrane electrode, increases the oxygen partial pressure and diffusion efficiency, and improves the output voltage, power and efficiency of the fuel cell. It also adapts the hydrogen storage pressure to fully convert the hydrogen pressure energy into electrical energy, reducing the waste of hydrogen pressure energy. At the same time, it ensures that the pressure inside and outside the fuel cell stack is always balanced, avoiding mechanical fatigue, damage and leakage accidents that may occur when the conventional fuel cell stack is running at high pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1This is a schematic diagram of the overall structure of a device for improving the performance of a fuel cell stack proposed by the present invention;

[0027] Figure 2 for Figure 1 A schematic diagram of a top view structure;

[0028] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure.

[0029] Among them, the figure markings are: 1, fuel cell stack; 2, pressurization chamber; 3, hydrogen circulation pump; 4, air supply pipeline; 5, nitrogen supply pipeline; 6, hydrogen supply pipeline; 7, pressure relief pipeline; 8, cooling water supply pipeline; 9, cooling water return pipeline; 10, hydrogen circulation pipeline; 11, air exhaust pipeline; 12, hydrogen exhaust pipeline; 13, air pressure reducing valve; 14, nitrogen pressure reducing valve; 15, hydrogen pressure reducing valve; 16, pressure relief valve; 17, air stop valve; 18, nitrogen stop valve; 19, hydrogen stop valve; 20, air-nitrogen stop valve; 21, hydrogen-nitrogen stop valve; 22, hydrogen back pressure valve; 23, air back pressure valve; 24, cooling water back pressure valve; 25, cooling water stop valve; 26, upper cover; 27, buckle; 28, box body. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] See attached Figure 1-3 A device for improving the performance of a fuel cell stack proposed in this embodiment includes a fuel cell stack 1, an air supply pipeline 4, an air exhaust pipeline 11, an air stop valve 17, an air pressure reducing valve 13, a nitrogen supply pipeline 5, a nitrogen stop valve 18, a nitrogen pressure reducing valve 14, a hydrogen supply pipeline 6, a hydrogen exhaust pipeline 12, a hydrogen stop valve 19, a hydrogen pressure reducing valve 15, an air-nitrogen stop valve 20, a hydrogen-nitrogen stop valve 21, an air back pressure valve 23, a hydrogen back pressure valve 22 and a box 28.

[0032] The upper cover 27 of the box body 28 is fixedly connected to the top of the side walls around it by a buckle 27, and the whole is a closed structure, and a pressurized chamber 2 is formed inside; the fuel cell stack 1 is arranged in the pressurized chamber 2 inside the box body 28; an air supply pipeline 4, a nitrogen supply pipeline 5 and a hydrogen supply pipeline 6 are arranged on one side of the box body 28 in sequence; one end of the air supply pipeline 4 located in the box body 28 is connected to the air intake pipeline of the fuel cell stack 1; the nitrogen supply pipeline 5 is connected to the air intake pipeline of the fuel cell stack 1; the The inner end of the pipeline 5 is connected to the pressurized chamber 2; the end of the hydrogen supply pipeline 6 located in the box body 28 is connected to the hydrogen inlet pipeline of the fuel cell stack 1; the other side of the box body 28 is provided with an air exhaust pipeline 11 and a hydrogen exhaust pipeline 12 in sequence; the end of the air exhaust pipeline 11 located in the box body 28 is connected to the air outlet pipeline of the fuel cell stack 1; the end of the hydrogen exhaust pipeline 12 located in the box body 28 is connected to the hydrogen outlet pipeline of the fuel cell stack 1.

[0033] An air pressure reducing valve 13 and an air stop valve 17 are sequentially installed at one end of the air supply pipeline 4 located outside the box 28; a nitrogen pressure reducing valve 14 and a nitrogen stop valve 18 are sequentially installed at one end of the nitrogen supply pipeline 5 located outside the box 28; a hydrogen pressure reducing valve 15 and a hydrogen stop valve 19 are sequentially installed at one end of the hydrogen supply pipeline 6 located outside the box 28; the air supply pipeline 4 and the nitrogen supply pipeline 5 are connected via an air-nitrogen stop valve 20; the nitrogen supply pipeline 5 and the hydrogen supply pipeline 6 are connected via a hydrogen-nitrogen stop valve 21; an air back-pressure valve 23 is installed at the outer end of the air exhaust pipeline 11; and a hydrogen back-pressure valve 22 is installed at the outer end of the hydrogen exhaust pipeline 12. A hydrogen circulation pipeline 10 is arranged in the pressurized chamber 2 inside the box body 28; one end of the hydrogen circulation pipeline 10 is connected to the hydrogen supply pipeline 6, and the other end is connected to the hydrogen exhaust pipeline 12, and a hydrogen circulation pump 3 is installed in the middle of the hydrogen circulation pipeline 10.

[0034] In this embodiment, an air stop valve 17, a nitrogen stop valve 18 and a hydrogen stop valve 19 are respectively installed on the inner sides of the air pressure reducing valve 13, the nitrogen pressure reducing valve 14 and the hydrogen pressure reducing valve 15 to suppress abnormal flow fluctuations and ensure stable operation of the air pressure reducing valve 13, the nitrogen pressure reducing valve 14 and the hydrogen pressure reducing valve 15.

[0035] A cooling water supply pipeline 8 and a cooling water return pipeline 9 are respectively provided on one side of the box body 28; the ends of the cooling water supply pipeline 8 and the cooling water return pipeline 9 located inside the box body 28 respectively pass through the wall of the pressurized chamber 2 and are connected to the cooling system of the fuel cell stack 1; a cooling water stop valve 25 is installed at the end of the cooling water supply pipeline 8 located outside the box body 28; a cooling water back-pressure valve 24 is installed at the end of the cooling water return pipeline 9 located outside the box body 28.

[0036] A pressure relief pipeline 7 is disposed on one side of the box body 28 ; the inner end of the pressure relief pipeline 7 is communicated with the pressurized chamber 2 inside the box body, and a pressure relief valve 16 is installed at one end outside the box body 28 .

[0037] An operating method of a device for improving the performance of a fuel cell stack, the specific implementation process is as follows:

[0038] S1. Before the fuel cell is operated, the air shut-off valve 17 and the hydrogen shut-off valve 19 are in a closed state; the air back-pressure valve 23, the hydrogen back-pressure valve 22 and the pressure relief valve 16 are adjusted to the same high pressure.

[0039] S2. Adjust the pressure of the nitrogen pressure reducing valve 14 to be slightly higher than the pressure relief valve 16, the hydrogen back pressure valve 22, and the air back pressure valve 23, slightly open the nitrogen stop valve 18, fully open the air-nitrogen stop valve 20 and the hydrogen-nitrogen stop valve 21, and inject nitrogen into the pressurizing chamber 2, the air supply pipeline 4, and the hydrogen supply pipeline 6 at the same time, and continue to increase the pressure to remove the residual gas in the pressurizing chamber 2 and the fuel cell stack 1.

[0040] S3. After the above steps, a certain pressure has been established inside the pressurized chamber 2 and the fuel cell stack 1. Close the air-nitrogen shut-off valve 20 and the hydrogen-nitrogen shut-off valve 21, adjust the air pressure reducing valve 13, the hydrogen pressure reducing valve 15 and the nitrogen pressure reducing valve 14 to the same state, and open the air shut-off valve 17 and the hydrogen shut-off valve 19 to supply high-pressure air and hydrogen to the air supply pipeline 4 and the hydrogen supply pipeline 6 respectively, and the fuel cell starts to operate.

[0041] S4. During the operation of the fuel cell, the exhaust gas is discharged through the air back pressure valve 23 and the hydrogen back pressure valve 22 respectively, and high-pressure nitrogen is continuously supplied to the pressurization chamber 2 at a low flow rate through the nitrogen pressure reducing valve 14 and the nitrogen stop valve 18 to dilute the trace hydrogen and air leaked from the fuel cell stack 1, and the exhaust gas is discharged through the pressure relief valve 16.

[0042] S5. After the operation of the fuel cell is finished, close the air shut-off valve 17 on the air supply pipeline 4 and the hydrogen shut-off valve 19 on the hydrogen supply pipeline 6, and open the air-nitrogen shut-off valve 20 and the hydrogen-nitrogen shut-off valve 21, and continue to supply nitrogen to the pressurizing chamber 2, the air supply pipeline 4, and the hydrogen supply pipeline 6, and blow out the residual air and hydrogen in the fuel cell stack 1 and the pressurizing chamber 2 through the air exhaust pipeline 11, the hydrogen exhaust pipeline 12, and the pressure relief pipeline 7, respectively.

[0043] S6. After the residual gas is purged, the nitrogen stop valve 18 is closed to stop the supply of high-pressure nitrogen.

[0044] It should be noted that, in the shutdown state, a certain pressure of nitrogen is maintained inside the pressurized chamber 2 and the fuel cell stack 1 to prevent air from entering, thereby extending the life of the fuel cell stack.

[0045] If it is necessary to open the pressurized chamber 2, first close the air shut-off valve 17, the nitrogen shut-off valve 18, and the hydrogen shut-off valve 19, open the air-nitrogen shut-off valve 20 and the hydrogen-nitrogen shut-off valve 21, and slowly adjust the pressure relief valve 16 to discharge the high-pressure nitrogen in the pressurized chamber 2 and the fuel cell stack 1 to achieve balance with the atmospheric pressure, then open the buckle 27 on the box body 28, remove the upper cover 26, and then operate the internal equipment.

[0046] The present invention improves the output voltage, power and efficiency of the fuel cell stack by increasing the pressure (density) of air and hydrogen in the fuel cell stack. At the same time, the pressure of the air and hydrogen flow channels inside the fuel cell stack is balanced with the outside (pressurized chamber), which can effectively avoid problems such as mechanical fatigue and leakage of the fuel cell stack.

[0047] Matters not described in detail in the present invention are all known technologies.

[0048] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for improving the performance of a fuel cell stack, characterized in that: The device comprises a fuel cell stack, an air supply pipeline, an air exhaust pipeline, an air stop valve, an air pressure reducing valve, a nitrogen supply pipeline, a nitrogen stop valve, a nitrogen pressure reducing valve, a hydrogen supply pipeline, a hydrogen exhaust pipeline, a hydrogen stop valve, a hydrogen pressure reducing valve, an air-nitrogen stop valve, a hydrogen-nitrogen stop valve, an air back pressure valve, a hydrogen back pressure valve and a box body; The box body is a closed structure, and a pressurized chamber is formed inside; the fuel cell stack is arranged in the pressurized chamber inside the box body; an air supply pipeline, a nitrogen supply pipeline and a hydrogen supply pipeline are sequentially arranged on one side of the box body, and the inner end of the air supply pipeline is connected to the air intake pipeline of the fuel cell stack; the inner end of the nitrogen supply pipeline is connected to the pressurized chamber; the inner end of the hydrogen supply pipeline is connected to the hydrogen intake pipeline of the fuel cell stack; an air exhaust pipeline and a hydrogen exhaust pipeline are sequentially arranged on the other side of the box body; the inner end of the air exhaust pipeline is connected to the air outlet pipeline of the fuel cell stack; the inner end of the hydrogen exhaust pipeline is connected to the hydrogen outlet pipeline of the fuel cell stack; An air pressure reducing valve and an air shut-off valve are sequentially installed at the outer end of the air supply pipeline; a nitrogen pressure reducing valve and a nitrogen shut-off valve are sequentially installed at the outer end of the nitrogen supply pipeline; a hydrogen pressure reducing valve and a hydrogen shut-off valve are sequentially installed at the outer end of the hydrogen supply pipeline; the air supply pipeline is connected to the nitrogen supply pipeline through an air-nitrogen shut-off valve; the nitrogen supply pipeline is connected to the hydrogen supply pipeline through a hydrogen-nitrogen shut-off valve; an air back-pressure valve is installed at the outer end of the air exhaust pipeline; and a hydrogen back-pressure valve is installed at the outer end of the hydrogen exhaust pipeline.

2. The device for improving the performance of a fuel cell stack according to claim 1, characterized in that: A cooling water supply pipeline and a cooling water return pipeline are respectively arranged on one side of the box body; the inner ends of the cooling water supply pipeline and the cooling water return pipeline are respectively connected to the cooling system of the fuel cell stack after passing through the box body pressurization chamber; a cooling water stop valve is installed at the outer end of the cooling water supply pipeline; and a cooling water back pressure valve is installed at the outer end of the cooling water return pipeline.

3. The device for improving the performance of a fuel cell stack according to claim 1, characterized in that: A pressure relief pipeline is arranged on one side of the box body; the inner end of the pressure relief pipeline is communicated with the pressurized chamber inside the box body, and a pressure relief valve is installed on the outer end.

4. The device for improving the performance of a fuel cell stack according to claim 1, characterized in that: A hydrogen circulation pipeline is arranged in the pressurized chamber inside the box; one end of the hydrogen circulation pipeline is connected to the hydrogen supply pipeline, and the other end is connected to the hydrogen exhaust pipeline, and a hydrogen circulation pump is installed in the middle of the hydrogen circulation pipeline.

5. The device for improving the performance of a fuel cell stack according to claim 1, characterized in that: The upper cover of the box body is fixedly connected to the top of the side wall by means of a buckle lock.

6. The operating method of the device for improving the performance of a fuel cell stack according to claim 3, characterized in that: The method comprises the following steps: S1. Before the fuel cell is operated, the air shut-off valve and the hydrogen shut-off valve are in a closed state; the air back pressure valve, the hydrogen back pressure valve and the pressure relief valve are adjusted to the same high pressure; S2. Adjust the pressure of the nitrogen pressure reducing valve to be slightly higher than that of the pressure relief valve, hydrogen back pressure valve, and air back pressure valve, slightly open the nitrogen stop valve, fully open the nitrogen-air stop valve and the nitrogen-hydrogen stop valve, and inject nitrogen into the pressurization chamber, air supply pipeline, and hydrogen supply pipeline at the same time, and continue to increase the pressure to remove the residual gas inside the pressurization chamber and the fuel cell stack; S3, after step S2, a certain pressure has been established inside the pressurized chamber and the fuel cell stack, the nitrogen-air shut-off valve and the nitrogen-hydrogen shut-off valve are closed, the air pressure reducing valve and the hydrogen pressure reducing valve are adjusted to the same state as the nitrogen pressure reducing valve, and the air shut-off valve and the hydrogen shut-off valve are opened to supply high-pressure air and hydrogen to the air supply pipeline and the hydrogen supply pipeline respectively, and the fuel cell starts to operate; S4. During the operation of the fuel cell, the exhaust gas is discharged from the air back pressure valve and the hydrogen back pressure valve respectively, and the high-pressure nitrogen is continuously supplied to the pressurization chamber at a low flow rate through the nitrogen pressure reducing valve and the nitrogen stop valve to dilute the trace hydrogen and air leaked from the fuel cell stack and discharged from the pressure relief valve; S5. After the fuel cell operation is finished, close the air shut-off valve and the hydrogen shut-off valve, and open the nitrogen-air shut-off valve and the nitrogen-hydrogen shut-off valve, and continue to supply nitrogen to the pressurized chamber and the fuel cell stack to purge the residual gas; S6. After completing the residual gas purging, close the nitrogen shut-off valve and stop supplying high-pressure nitrogen.

7. The operating method of the device for improving the performance of a fuel cell stack according to claim 6, characterized in that: In the shutdown state, a certain pressure of nitrogen is maintained inside the pressurized chamber and the fuel cell stack.

8. The operating method of the device for improving the performance of a fuel cell stack according to claim 6, characterized in that: If you need to open the pressurized chamber, first close the air shut-off valve, nitrogen shut-off valve, and hydrogen shut-off valve, open the nitrogen-air shut-off valve and nitrogen-hydrogen shut-off valve, and slowly adjust the pressure relief valve to discharge the high-pressure nitrogen in the pressurized chamber and the fuel cell stack to achieve balance with the atmospheric pressure, then open the buckle on the box and remove the upper cover.

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