A hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system

Abstract

This invention relates to a hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system, comprising a gas-liquid separator, an inlet three-way valve, an outlet three-way valve, a nitrogen condenser, and a hydrogen circulation component. The mixed gas from the fuel cell stack's hydrogen outlet enters the gas-liquid separator to separate liquid water. The outlet of the gas-liquid separator is connected to the inlet of the inlet three-way valve; the first outlet of the inlet three-way valve is connected to the first inlet of the outlet three-way valve; the second outlet of the inlet three-way valve is connected to the inlet of the nitrogen condenser; the outlet of the nitrogen condenser is connected to the second inlet of the outlet three-way valve; the nitrogen condenser liquefies the nitrogen in the mixed gas entering it into liquid nitrogen; the outlet of the outlet three-way valve is connected to the hydrogen circulation component. This invention solves the problems of large fluctuations in hydrogen circuit pressure and low hydrogen utilization rate that are common in conventional hydrogen removal valve nitrogen removal methods, effectively extending fuel cell life and improving system hydrogen utilization rate.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology and relates to a hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system. Background Technology

[0002] Hydrogen fuel cells are devices that directly convert the chemical energy of hydrogen and oxygen into electrical energy. They have advantages such as being environmentally friendly and pollution-free, having low noise, and high power generation efficiency, and have broad application prospects in aerospace, vehicles, ships, drones and other fields.

[0003] To improve the reaction efficiency of fuel cells, an oversupply of hydrogen is usually adopted, and the exhaust hydrogen is recycled. As the fuel cell operates for longer, nitrogen and water that permeate from the cathode to the anode accumulate in the hydrogen circulation system. If the impurity gases are not removed in time, they will seriously affect the performance of the fuel cell system.

[0004] Impurity gases and liquid water in the hydrogen circuit of a fuel cell are generally discharged through hydrogen venting valves and water drain valves. When the hydrogen venting valve is opened, the hydrogen pressure fluctuates significantly, increasing the pressure difference across the membrane electrode assembly (MEA) inside the fuel cell stack. This leads to mechanical damage to the MEA and causes performance degradation of the fuel cell. Furthermore, as fuel cell systems are developed to handle hundreds of kilowatts or even higher power, the disadvantages of traditional hydrogen venting valves in ensuring system hydrogen utilization and pressure stabilization are becoming increasingly apparent. While the hydrogen venting valve discharges impurity nitrogen, a large amount of hydrogen is also discharged simultaneously, resulting in more serious hydrogen waste. Moreover, the reliability and service life of the fuel cell stack cannot be guaranteed. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system. The hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system increases the hydrogen concentration entering the stack by using nitrogen in the low-temperature cold source liquefied hydrogen circulation pipeline. This solves the problems of large fluctuations in hydrogen circuit pressure and low hydrogen utilization rate that are common in conventional hydrogen removal valve nitrogen removal methods. It can effectively extend the life of the fuel cell and improve the system hydrogen utilization rate.

[0006] The solution of the present invention is: a hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system, comprising a gas-water separator, an inlet three-way valve, an outlet three-way valve, a nitrogen condenser, a first circulation pipeline, a condenser inlet pipeline, a condenser outlet pipeline, and hydrogen circulation components;

[0007] The mixed gas from the hydrogen outlet of the fuel cell stack enters a gas-liquid separator to separate liquid water. The outlet of the gas-liquid separator is connected to the inlet of an inlet three-way valve. The first outlet of the inlet three-way valve is connected to the first inlet of the outlet three-way valve through a first circulation pipeline. The second outlet of the inlet three-way valve is connected to the inlet of a nitrogen condenser through a condenser inlet pipeline. The outlet of the nitrogen condenser is connected to the second inlet of the outlet three-way valve through a condenser outlet pipeline. The nitrogen condenser is used to liquefy the nitrogen in the mixed gas entering it into liquid nitrogen. The outlet of the outlet three-way valve is connected to the inlet of a hydrogen circulation component. The outlet of the hydrogen circulation component is connected to the hydrogen inlet of the fuel cell stack.

[0008] Furthermore, the nitrogen condenser is equipped with a condensing component, which is connected to a low-temperature cold source via a cold belt and is connected in series with a manifold. The cold belt is used to transfer the cold energy of the low-temperature cold source to the condensing component, and the low-temperature cold source is used to cool the cold belt and the condensing component to below a preset temperature. The condensing component is used to exchange heat with the mixed gas within the allowable range of the flow resistance value of the nitrogen condenser.

[0009] Furthermore, the cryogenic cold source includes one of the following: a refrigerator, subcooled liquid nitrogen, or liquid hydrogen.

[0010] Furthermore, it also includes a liquid nitrogen buffer tank and a first drain pipe. The inlet of the liquid nitrogen buffer tank is connected to the manifold of the nitrogen condenser through the first drain pipe, and the first drain pipe is equipped with an inlet valve.

[0011] Furthermore, it also includes a second drain pipe, which is connected to the outlet of the liquid nitrogen buffer tank, and is equipped with a drain valve.

[0012] Furthermore, the liquid nitrogen buffer tank is equipped with a level gauge; when the level gauge detects that the liquid nitrogen level has reached the set upper limit, the inlet valve closes and the outlet valve opens; when the level gauge detects that the liquid nitrogen level is lower than the set lower limit, the inlet valve opens and the outlet valve closes.

[0013] Furthermore, by adjusting the opening angle of the inlet three-way valve, the flow area of ​​its air inlet, the first circulation pipeline, and the condenser air inlet pipeline can be controlled.

[0014] Furthermore, by adjusting the opening angle of the outlet three-way valve, the flow area of ​​its outlet, the first circulation pipeline, and the condenser outlet pipeline can be controlled.

[0015] Furthermore, the cold strip, manifold, first drain pipe, inlet valve, liquid nitrogen buffer tank, drain valve, and second drain pipe are all insulated with heat-insulating measures.

[0016] Furthermore, when the nitrogen purging device purges nitrogen, the inlet of the inlet three-way valve is connected to the second outlet of the inlet three-way valve, but not to the first outlet of the inlet three-way valve; the outlet of the outlet three-way valve is connected to the second inlet of the outlet three-way valve, but not to the first inlet of the outlet three-way valve.

[0017] The advantages of this invention compared to the prior art are:

[0018] (1) The hydrogen circuit pressure stabilization and nitrogen removal device for fuel cell systems provided by this invention condenses and liquefies nitrogen in the nitrogen condenser using a low-temperature cold source. The liquid nitrogen flows into a liquid nitrogen buffer tank and is discharged after accumulating to a certain amount. The hydrogen circulating in the nitrogen condenser flows to the hydrogen circulation component through the outlet of the nitrogen condenser and finally enters the fuel cell stack to participate in the reaction. The pressure drop caused by nitrogen liquefaction in the nitrogen condenser is slow, and the hydrogen circuit pressure does not fluctuate significantly. Furthermore, the liquid nitrogen in the liquid nitrogen buffer tank is discharged by controlling the opening and closing of the inlet valve and the outlet valve, which does not cause the simultaneous discharge of hydrogen. It has advantages such as high hydrogen utilization rate, stable and controllable hydrogen circulation circuit pressure, and benefit from extending the service life of the fuel cell.

[0019] (2) The nitrogen condenser in the hydrogen circuit pressure stabilization and nitrogen removal device of the fuel cell system provided by the present invention utilizes the difference in liquefaction temperature between hydrogen and nitrogen to liquefy only nitrogen without changing the mass flow rate of hydrogen in the hydrogen circulation circuit, thereby avoiding unnecessary waste of hydrogen. In addition, the nitrogen condenser can be integrated with the gas-water separator to improve the integration of the system and help reduce the volume and weight of the system.

[0020] (3) The hydrogen circuit pressure stabilization and nitrogen removal device and its implementation method for fuel cell systems provided by the present invention can be a refrigerator, subcooled liquid nitrogen, liquid hydrogen or other cold source devices that can cool the condensing components in the cold zone and nitrogen condenser to below 77K. The present invention is particularly suitable for hydrogen fuel cell systems with sufficient low-temperature cooling capacity and strict restrictions on hydrogen removal, such as UAV airborne liquid hydrogen storage tank fuel cell engine systems, vehicle-mounted liquid hydrogen storage tank fuel cell engine systems and fuel cell power generation systems operating in an environment with sufficient liquid nitrogen cold source. Attached Figure Description

[0021] Figure 1 This is a diagram showing the composition and connection of the pressure stabilizing and nitrogen removal device according to an embodiment of the present invention.

[0022] The components include: 1. Fuel cell stack; 101. Stack hydrogen outlet; 102. Stack hydrogen inlet; 2. First hydrogen discharge pipe; 3. Gas-liquid separator; 4. Drain valve; 5. Hydrogen concentration meter; 6. Second hydrogen discharge pipe; 7. Inlet three-way valve; 8. Condenser inlet pipe; 9. Nitrogen condenser; 901. Condenser component; 902. Condenser shell; 903. Manifold; 10. Cooling strip; 11. Cryogenic cold source; 12. First liquid discharge pipe; 13. Liquid inlet valve; 14. Liquid nitrogen buffer tank; 15. Liquid level gauge; 16. Liquid discharge valve; 17. Second liquid discharge pipe; 18. First circulation pipe; 19. Condenser outlet pipe; 20. Outlet three-way valve; 21. Hydrogen return pipe; 22. Hydrogen circulation component; 23. Hydrogen source assembly. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments.

[0024] Example 1

[0025] This invention discloses a hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system. The nitrogen removal system includes a fuel cell stack 1, a first hydrogen removal pipe 2, a gas-liquid separator 3, a drain valve 4, a hydrogen concentration meter 5, a second hydrogen removal pipe 6, an inlet three-way valve 7, a condenser inlet pipe 8, a nitrogen condenser 9, a cooling belt 10, a cryogenic cold source 11, a first liquid drain pipe 12, a liquid inlet valve 13, a liquid nitrogen buffer tank 14, a level gauge 15, a drain valve 16, a second liquid drain pipe 17, a first circulation pipe 18, a condenser outlet pipe 19, an outlet three-way valve 20, a hydrogen return pipe 21, a hydrogen circulation component 22, and a hydrogen source assembly 23.

[0026] The hydrogen inlet 102 of the fuel cell stack 1 is connected to the outlet of the hydrogen source assembly 23 and the outlet of the hydrogen circulation component 22, respectively. The hydrogen outlet 101 of the stack is connected to the inlet of the gas-liquid separator 3 through the first hydrogen discharge pipe 2. The liquid outlet of the gas-liquid separator 3 is connected to the drain valve 4, and the gas outlet of the gas-liquid separator 3 is connected to the inlet of the inlet three-way valve 7 through the second hydrogen discharge pipe 6. The first outlet of the inlet three-way valve 7 is connected to the first inlet of the outlet three-way valve 20 through the first circulation pipe 18, and the second outlet of the inlet three-way valve 7 is connected to the inlet of the nitrogen condenser 9 through the condenser inlet pipe 8. A hydrogen concentration meter 5 is installed on the second hydrogen discharge pipe 6.

[0027] The outlet of the nitrogen condenser 9 is connected to the second inlet of the outlet three-way valve 20 through the condenser outlet pipe 19; the outlet of the outlet three-way valve 20 is connected to the inlet of the hydrogen circulation component 22 through the hydrogen return pipe 21; the outlet of the hydrogen circulation component 22 is connected to the hydrogen inlet of the fuel cell stack.

[0028] The inlet of the liquid nitrogen buffer tank 14 is connected to the outlet of the nitrogen condenser via a first drain pipe 12, and an inlet valve 13 is installed on the first drain pipe 12. The second drain pipe 17 is connected to the outlet of the liquid nitrogen buffer tank 14, and a drain valve 16 is installed on the second drain pipe 17. A level gauge 15 is installed on the liquid nitrogen buffer tank 14.

[0029] The low-temperature cold source 11 is connected to the nitrogen condenser 9 through the cold belt 10.

[0030] Specifically, the nitrogen condenser 9 includes a condenser shell 901, inside which a condensing component 901 is disposed, and the condensing component is connected in series with a manifold 903; wherein, the condensing component is used to fully exchange heat with the mixed gas within the allowable range of the flow resistance value of the nitrogen condenser 9. The low-temperature cold source 11 reduces the temperature of the condensing component 901 to below 77K through the cold belt 10. When the mixed gas entering the nitrogen condenser 9 comes into contact with the surface of the condensing component 901, the nitrogen in the mixed gas is condensed into liquid nitrogen. The shape of the condensing component can be disc-shaped, spiral-shaped, rectangular, or other irregular shapes.

[0031] The low-temperature cold source is used to cool the condenser component 901, keeping the temperature of the cold end component below 77K. The low-temperature cold source 11 is connected to the condenser component 901 via a cold belt 10, and the cooling capacity of the low-temperature cold source 11 is also transferred to the condenser component 901 through the cold belt 10. The low-temperature cold source 11 can be a refrigerator, subcooled liquid nitrogen, liquid hydrogen, or other cold source capable of cooling the condenser component in the cold belt and nitrogen condenser to below 77K.

[0032] The upper end of the manifold 903 is connected to the condenser 901, and the lower end of the manifold 903 is connected to the first drain pipe 12. The liquid nitrogen condensed by the condenser 901 is collected in the manifold 903 under the action of gravity or other forces.

[0033] The cold strip 10 is made of a material with good thermal conductivity and its shape is not subject to special requirements. It is mainly used to transfer the cold energy of the low-temperature cold source 11 to the condenser component 901.

[0034] The level gauge 15 is installed on the liquid nitrogen buffer tank 14 and is used to monitor the liquid nitrogen level in the liquid nitrogen buffer tank 14.

[0035] The inlet three-way valve 7 has two positions: position 0 and position 1. In practice, when the inlet three-way valve is in position 0, its inlet port is connected to its first outlet port but not to its second outlet port; that is, the second hydrogen exhaust pipe 6 is connected to the first circulation pipe 18 but not to the condenser inlet pipe 8. When the inlet three-way valve is in position 1, its inlet port is connected to its second outlet port but not to its first outlet port; that is, the second hydrogen exhaust pipe 6 is not connected to the first circulation pipe 18 but is connected to the condenser inlet pipe 8.

[0036] The imported three-way valve 7 of the present invention is used to control the flow area between the second hydrogen exhaust pipe 6 and the first circulation pipe 18 and the condenser inlet pipe 8. The position of its valve core includes, but is not limited to, positions 0 and 1, or can be between 0 and 1, so that both the first circulation pipe and the condenser inlet pipe 8 can have a certain amount of mixed gas flow.

[0037] The outlet three-way valve 20 has two positions: 0 and 1. In practice, when the outlet three-way valve 20 is in position 0, its outlet is connected to its first inlet but not to its second inlet; that is, the hydrogen return line 21 is connected to the first circulation line 18 but not to the condenser outlet line 19. When the outlet three-way valve is in position 1, its outlet is connected to its second inlet but not to its first inlet; that is, the hydrogen return line 21 is not connected to the first circulation line 18 but is connected to the condenser outlet line 19. The outlet three-way valve 20 is used to control the connection and disconnection between the hydrogen return line 21, the first circulation line 18, and the condenser outlet line 19.

[0038] The outlet three-way valve of the present invention is used to control the flow area between the hydrogen return pipeline 21, the first circulation pipeline 18, and the condenser outlet pipeline 19. The valve core is located in a position including but not limited to the 0 and 1 positions, or between 0 and 1, so that both the first circulation pipeline and the condenser outlet pipeline 19 can have a certain amount of mixed gas flow.

[0039] In the specific implementation process, for example, the valve core positions of the inlet three-way valve 7 and the outlet three-way valve 20 are only two states: 0 and 1. However, the present invention can control the opening angle of the three-way valve by controlling the motor, thereby controlling the flow distribution of the mixed gas into the first circulation pipeline 18 and the nitrogen condenser 9. That is, it can control all the mixed gas to enter the nitrogen condenser 9, or it can make part of the mixed gas enter the nitrogen condenser 9 and the rest of the mixed gas enter the first circulation pipeline 18.

[0040] The components such as the cooling belt 10, manifold 903, first drain pipe 12, inlet valve 13, liquid nitrogen buffer tank 14, drain valve 16, and second drain pipe 17 need to be insulated with certain heat-insulating measures, such as vacuum jackets, to reduce the heat transfer from the external environment and ensure that the above components can be cooled to a certain value in a very short time, thereby shortening the time required for liquid nitrogen to flow into the liquid nitrogen buffer tank to reach the set liquid level.

[0041] The working process of the pressure stabilizing and nitrogen removal device described in this invention is as follows:

[0042] (1) When the fuel cell stack 1 is running stably, the working process of the hydrogen supply module of the fuel cell system is as follows: When the hydrogen concentration meter 5 detects that the hydrogen concentration in the second hydrogen exhaust pipe 6 is higher than the set value, the inlet three-way valve 7 is in position 0, the outlet three-way valve is in position 0, the low temperature cold source 11 is in the closed state, the liquid inlet valve 13 and the liquid outlet valve 16 are both in the closed state, the hydrogen-nitrogen mixture and liquid water flowing out of the stack hydrogen outlet 101 enter the first hydrogen exhaust pipe 2, and then enter the gas-water separator 3. The liquid water is separated by the gas-water separator, the hydrogen and nitrogen mixture enters the second hydrogen exhaust pipe 6, and enters the first circulation pipeline 18 through the inlet three-way valve 7, and then enters the hydrogen circulation component 22 through the outlet three-way valve 20. Under the push of the hydrogen circulation component, it re-enters the stack to participate in the oxidation-reduction reaction.

[0043] (2) As the fuel cell stack reaction proceeds, more and more nitrogen permeates from the air side of the proton exchange membrane inside the fuel cell stack to the hydrogen side, resulting in a decrease in the hydrogen concentration on the hydrogen side. When the hydrogen concentration meter 5 detects that the hydrogen concentration is lower than the set value, the nitrogen purging mode is activated. The hydrogen-nitrogen mixture and liquid water flowing out of the fuel cell stack hydrogen outlet 101 enter the first hydrogen purging pipe 2, and then enter the gas-water separator 3. The liquid water is separated by the gas-water separator 3. The hydrogen-nitrogen mixture enters the second hydrogen purging pipe 6, and then enters the nitrogen condenser 9 through the inlet three-way valve 7 and the condenser inlet pipe 8. The nitrogen in the mixture is liquefied and collected in the liquid nitrogen buffer tank 14. The hydrogen and unliquefied nitrogen flow through the condenser outlet pipe 19, the outlet three-way valve 20, and the hydrogen return pipe 21 into the hydrogen circulation component 22, and then into the fuel cell stack 1. The hydrogen and nitrogen that did not participate in the reaction enter the nitrogen condenser 9 again. This cycle continues until the hydrogen concentration meter 5 detects that the hydrogen concentration in the second hydrogen discharge pipe 6 is higher than the set value. At this point, the inlet valve 13 closes, the drain valve 16 opens, the cryogenic cold source 11 stops working, and when the liquid nitrogen in the liquid nitrogen buffer tank 14 is drained, the drain valve 16 closes, the inlet three-way valve 7 is in position 0, the outlet three-way valve 20 is in position 0, the mixed gas flows through the first circulation pipe 18, and the system's nitrogen discharge mode is turned off.

[0044] More specifically, the nitrogen purging mode is as follows: After entering the nitrogen purging mode, both the inlet three-way valve 7 and the outlet three-way valve 20 are in position 1, the liquid inlet valve 13 is opened, the low-temperature cold source 11 cools the condenser component 901 to below 77K through the cold belt 10 and maintains it, the hydrogen-nitrogen mixture and liquid water flowing out of the hydrogen outlet 102 of the fuel cell stack enter the first hydrogen purging pipe 2, and then enter the gas-water separator 3. The liquid water is separated by the gas-water separator 3. The hydrogen-nitrogen mixture flows through the second hydrogen purging pipe 6, the inlet three-way valve 7, and the condenser inlet pipe 8, and then enters the nitrogen condenser 9. The nitrogen in the mixture comes into contact with the condenser 901 and releases heat to cool down and condense into liquid nitrogen. The liquid nitrogen formed flows into the manifold 903 under the action of gravity or other forces, and flows through the upper liquid drain pipe 12 and the liquid inlet valve 13 in sequence, and is finally stored in the liquid nitrogen buffer tank 14. If the internal temperature of the upper drain pipe 12, the inlet valve 13, and the liquid nitrogen buffer tank 14 is higher than 77K, the liquid nitrogen will first absorb heat and vaporize to reduce the internal temperature of the upper drain pipe 12, the inlet valve 13, and the liquid nitrogen buffer tank 14 to below 77K, and then continue to accumulate in the liquid nitrogen buffer tank 14. When the liquid nitrogen level gauge 15 in the liquid nitrogen buffer tank 14 detects that the liquid nitrogen level has reached the set upper limit, the inlet valve 13 closes and the drain valve 16 opens. When the liquid nitrogen level gauge 15 detects that the liquid nitrogen level in the liquid nitrogen buffer tank 14 is lower than the set lower limit, the inlet valve 13 opens and the drain valve 16 closes. The nitrogen in the mixed gas continues to be condensed and liquefied and flows into the liquid nitrogen buffer tank 14. The hydrogen and the unliquefied nitrogen enter the fuel cell stack 1 through the condenser outlet pipe 19, the outlet three-way valve 20, the hydrogen circulation component 22, etc. The mixed gas and liquid water flowing out of the hydrogen outlet 101 of the stack re-enter the gas-water separator 3 and the nitrogen condenser 9, etc. In this cycle, the nitrogen concentration on the hydrogen side of the stack will continuously decrease and the hydrogen concentration will continuously increase.

[0045] The pressure stabilization and nitrogen removal device proposed in this invention can ensure stable and controllable hydrogen pressure and stable system power output while keeping the impurity nitrogen in the hydrogen path at a low level. This is beneficial for improving hydrogen utilization, reducing the impact and damage of pressure fluctuations on the fuel cell membrane electrode assembly, and extending the service life of the fuel cell.

[0046] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A fuel cell system hydrogen circuit pressure regulating nitrogen venting device, characterized by, Includes a gas-water separator (3), an inlet three-way valve (7), an outlet three-way valve (20), a nitrogen condenser (9), a first circulation pipeline (18), a condenser inlet pipeline (8), a condenser outlet pipeline (19), and a hydrogen circulation component (22). The mixed gas from the hydrogen outlet of the fuel cell stack enters the gas-water separator (3) to separate liquid water; the outlet of the gas-water separator (3) is connected to the inlet of the inlet three-way valve (7), the first outlet of the inlet three-way valve (7) is connected to the first inlet of the outlet three-way valve (20) through the first circulation pipeline (18), and the second outlet of the inlet three-way valve (7) is connected to the inlet of the nitrogen condenser (9) through the condenser inlet pipeline (8); the outlet of the nitrogen condenser (9) is connected to the second inlet of the outlet three-way valve (20) through the condenser outlet pipeline (19); the nitrogen condenser (9) is used to liquefy the nitrogen in the mixed gas entering it into liquid nitrogen; the outlet of the outlet three-way valve (20) is connected to the inlet of the hydrogen circulation component (22); the outlet of the hydrogen circulation component (22) is connected to the hydrogen inlet of the fuel cell stack. The nitrogen condenser (9) is equipped with a condensing component (901). The condensing component (901) is connected to the low-temperature cold source (11) through a cold belt (10). The condensing component (901) is connected in series with a manifold (903). The cold belt (10) is used to conduct the cold energy of the low-temperature cold source (11) to the condensing component (901). The low-temperature cold source (11) is used to cool the cold belt (10) and the condensing component (901) to below the preset temperature. The condensing component is used to exchange heat with the mixed gas within the allowable range of the flow resistance value of the nitrogen condenser (9).

2. The fuel cell system hydrogen circuit pressure regulating nitrogen discharge apparatus according to claim 1, characterized by The low-temperature cold source (11) includes one of the following: a refrigerator, subcooled liquid nitrogen, or liquid hydrogen.

3. The fuel cell system hydrogen circuit pressure regulating nitrogen venting device of claim 1, wherein, It also includes a liquid nitrogen buffer tank (14) and a first drain pipe (12). The inlet of the liquid nitrogen buffer tank (14) is connected to the manifold (903) of the nitrogen condenser through the first drain pipe (12). The first drain pipe (12) is equipped with a liquid inlet valve (13).

4. The fuel cell system hydrogen circuit pressure regulating nitrogen discharge apparatus according to claim 3, wherein It also includes a second drain pipe (17), which is connected to the outlet of the liquid nitrogen buffer tank (14), and a drain valve (16) is provided on the second drain pipe (17).

5. The hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system according to claim 4, characterized in that, The liquid nitrogen buffer tank (14) is equipped with a level gauge (15); when the level gauge (15) detects that the liquid nitrogen level reaches the set upper limit value, the inlet valve (13) is closed and the drain valve (16) is opened; when the level gauge (15) detects that the liquid nitrogen level is lower than the set lower limit value, the inlet valve (13) is opened and the drain valve (16) is closed.

6. The hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system according to claim 1, characterized in that, By adjusting the opening angle of the inlet three-way valve (7), the flow area of ​​its air inlet, the first circulation pipeline (18), and the condenser air inlet pipeline (8) can be controlled.

7. The hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system according to claim 1, characterized in that, By adjusting the opening angle of the outlet three-way valve (20), the flow area of ​​its outlet, the first circulation pipeline (18), and the condenser outlet pipeline (19) can be controlled.

8. The hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system according to claim 4, characterized in that, The cold strip (10), manifold (903), first drain pipe (12), inlet valve (13), liquid nitrogen buffer tank (14), drain valve (16), and second drain pipe (17) are all insulated.

9. The hydrogen circuit pressure stabilization and nitrogen removal device for a fuel cell system according to claim 1, characterized in that, When the nitrogen removal device removes nitrogen, the inlet of the inlet three-way valve (7) is connected to the second outlet of the inlet three-way valve (7) and not connected to the first outlet of the inlet three-way valve (7); the outlet of the outlet three-way valve (20) is connected to the second inlet of the outlet three-way valve (20) and not connected to the first inlet of the outlet three-way valve (20).

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