A method for high-efficiency gas replacement during start-up of a fuel cell system

Abstract

The application provides a fuel cell system starting high-efficiency gas replacement method, and belongs to the technical field of fuel cells. The method solves the technical problem of low replacement efficiency of the existing gas replacement method. The fuel cell system starting high-efficiency gas replacement method comprises the following steps: S1, opening the air inlet throttle valve of the fuel cell system, closing the air inlet throttle valve of the fuel cell system after the pressure on the cathode side of the fuel cell system is restored, so as to improve the upper limit of the pressure on the anode side during replacement; S2, adjusting the hydrogen system of the fuel cell system to maintain the pressure on the anode side of the fuel cell system; S3, intermittently opening the hydrogen tail exhaust pipe to exhaust the inert gas on the anode side of the fuel cell system; S4, opening the air inlet throttle valve and the air outlet throttle valve of the fuel cell system; S5, starting the air compressor, and large-flow air enters the cathode side of the fuel cell system to exhaust the inert gas on the cathode side of the fuel cell system, and the gas replacement is completed. The application has the advantages of high replacement efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fuel cells, and relates to a gas replacement method, in particular to a high-efficiency gas replacement method for starting a fuel cell system. BACKGROUND

[0002] After the fuel cell system is stopped for a period of time, oxygen in the cathode cavity of the electric pile will consume all the hydrogen in the anode cavity of the electric pile, and the inert gas nitrogen on the cathode side will diffuse to the anode side through the proton exchange membrane, so that the cathode side and the anode side of the electric pile are both inert gas nitrogen before the fuel cell system is started, and the inert gas nitrogen with high concentration will cause the performance of the battery single piece to be low after the fuel cell system is started, increase the starting time, and even cause the starting to fail.

[0003] At present, the existing gas replacement method for starting the fuel cell system adopts conventional purging, and the replacement efficiency is low and the replacement effect is general, so it is necessary to design a high-efficiency gas replacement method for starting the fuel cell system. SUMMARY

[0004] The purpose of the present application is to solve the problems of low replacement efficiency and general replacement effect of the existing replacement method.

[0005] The purpose of the present application can be realized by the following technical scheme: a high-efficiency gas replacement method for starting a fuel cell system, characterized in that it comprises the following steps:

[0006] S1, opening the air inlet throttle valve of the fuel cell system, closing the air inlet throttle valve of the fuel cell system after restoring the pressure on the cathode side of the fuel cell system, so as to improve the upper limit of the pressure on the anode side during replacement;

[0007] S2, adjusting the hydrogen system of the fuel cell system to maintain the pressure on the anode side of the fuel cell system;

[0008] S3, intermittently opening the hydrogen tail exhaust pipe to discharge the inert gas on the anode side of the fuel cell system;

[0009] S4, opening the air inlet throttle valve and the air outlet throttle valve of the fuel cell system;

[0010] S5, starting the air compressor, and large-flow air enters the cathode side of the fuel cell system to discharge the inert gas on the cathode side of the fuel cell system, and the gas replacement is completed;

[0011] The fuel cell system comprises an electric pile, an air system and a hydrogen system, the air system is used for supplying air to the electric pile, and the hydrogen system is used for supplying hydrogen to the electric pile.

[0012] The air system comprises an air compressor, an air inlet throttle valve and an air outlet throttle valve, the air compressor is connected with the cathode inlet of the fuel cell through the air inlet throttle valve, the cathode outlet of the fuel cell is connected with the air outlet throttle valve, and the air system further comprises an air humidifier for humidifying air.

[0013] The hydrogen system comprises a hydrogen high-pressure bottle, a hydrogen decompression valve and a hydrogen tail exhaust valve, the hydrogen high-pressure bottle is connected with the anode inlet of the fuel cell through the hydrogen decompression valve, the anode outlet of the fuel cell is connected with the hydrogen tail exhaust valve, and the hydrogen system further comprises a hydrogen circulation pump for circulating hydrogen.

[0014] The front end of the air compressor is further provided with an air filter for filtering air, the cathode inlet of the fuel cell is provided with an air inlet pressure sensor, the cathode outlet of the fuel cell is provided with an air outlet pressure sensor, and the cathode outlet of the fuel cell is provided with a hydrogen inlet pressure sensor.

[0015] In the step S1, the air inlet throttle valve of the fuel cell system is opened, the target angle of the air inlet throttle valve is set to 10°, and when the air inlet pressure sensor detects that the pressure is greater than 100Kap, the target angle of the air inlet throttle valve is set to 0°.

[0016] In the step S2, the hydrogen decompression valve is opened, the opening angle of the hydrogen decompression valve is adjusted in real time according to the pressure feedback of the hydrogen inlet pressure sensor, and the pressure on the anode side of the fuel cell system is maintained at 150Kpa.

[0017] In the step S3, the pressure on the anode side of the fuel cell system is maintained at 150Kpa, the hydrogen tail exhaust valve is opened for 0.5 seconds every 1 second, and after 3 seconds, all the inert gases on the anode side of the fuel cell system can be completely exhausted.

[0018] In the step S4, the opening degrees of the air inlet throttle valve and the air outlet throttle valve are set to 90°.

[0019] In the step S5, the rotating speed of the air compressor is set to 30000rpm, and after the rotating speed of the air compressor reaches 30000rpm, a large amount of air is brought into the cathode side of the fuel cell system, and after 2 seconds, the inert gases on the cathode side of the fuel cell system are replaced and exhausted, and the system replacement is completed.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] 1. Since the pressure during the replacement of the anode side of the fuel cell is improved, and the hydrogen tail exhaust valve is periodically opened and closed, the replacement efficiency of the impurity gases on the anode side of the fuel cell is greatly improved, and the starting time of the fuel cell system is shortened.

[0022] 2. Since the pressure is higher, the replacement of the inert gases on the anode side is cleaner, the voltage of the single cell is higher, and the starting success rate of the fuel cell system is improved. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the fuel cell system of the present invention.

[0024] In the diagram, 1. Air filter; 2. Air compressor; 3. Inlet throttle valve; 4. Air humidifier; 5. Outlet throttle valve; 6. Air inlet pressure sensor; 7. Air outlet pressure sensor; 8. Fuel cell stack; 11. Hydrogen pressure reducing valve; 12. Hydrogen inlet pressure sensor; 13. Hydrogen tailpipe valve; 14. Hydrogen circulation pump; 15. High-pressure hydrogen cylinder. Detailed Implementation

[0025] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0026] like Figure 1 As shown, the efficient gas replacement method for starting up this fuel cell system includes the following steps in this embodiment:

[0027] S1. Open the intake throttle valve 3 of the fuel cell system to restore the cathode side pressure of the fuel cell system, and then close the intake throttle valve 3 of the fuel cell system to increase the upper limit of the anode side pressure during the replacement period.

[0028] S2. Regulate the hydrogen system of the fuel cell system to maintain the anode side pressure of the fuel cell system;

[0029] S3. Intermittently open the hydrogen tailpipe to discharge the inert gas on the anode side of the fuel cell system;

[0030] S4. Open the intake throttle valve 3 and the exhaust throttle valve 5 of the fuel cell system;

[0031] S5. Turn on air compressor 2. A large flow of air enters the cathode side of the fuel cell system and discharges the inert gas on the cathode side of the fuel cell system, completing the gas replacement.

[0032] The fuel cell system includes stack 8, an air system, and a hydrogen system. The air system supplies air to stack 8, and the hydrogen system supplies hydrogen to stack 8.

[0033] The air system includes an air compressor 2, an intake throttle valve 3, and an outlet throttle valve 5. The air compressor 2 is connected to the cathode inlet of the fuel cell stack 8 through the intake throttle valve 3, and the cathode outlet of the fuel cell stack 8 is connected to the outlet throttle valve 5. The air system also has an air humidifier 4 for humidifying the air.

[0034] The hydrogen system comprises a hydrogen high-pressure bottle 15, a hydrogen pressure reducing valve 11 and a hydrogen tail valve 13. The hydrogen high-pressure bottle 15 is connected to the anode inlet of the stack 8 through the hydrogen pressure reducing valve 11. The anode outlet of the stack 8 is connected to the hydrogen tail valve 13. The hydrogen system further comprises a hydrogen circulating pump 14 for circulating hydrogen.

[0035] The front end of the air compressor 2 is further provided with an air filter 1 for filtering air. The cathode inlet of the stack 8 is provided with an air inlet pressure sensor 6. The cathode outlet of the stack 8 is provided with an air outlet pressure sensor 7 and a hydrogen inlet pressure sensor 12.

[0036] In the embodiment, after the fuel cell system is stopped for a period of time, the cathode side of the stack 8 and the anode side of the stack 8 are both filled with inert gas nitrogen. Since the hydrogen and oxygen inside the stack 8 are consumed, the cathode and the anode of the stack 8 are both in a negative pressure state. In the embodiment, the air inlet pressure sensor 6, the air outlet pressure sensor 7 and the hydrogen inlet pressure sensor 12 are all 70 Kpa.

[0037] In step S1, the air inlet throttle valve 3 of the fuel cell system is opened. The target angle of the air inlet throttle valve 3 is set to 10°. When the air inlet pressure sensor 6 detects that the pressure is greater than 100 Kpa, the target angle of the air inlet throttle valve 3 is set to 0°.

[0038] In step S2, the hydrogen pressure reducing valve 11 is opened. The opening angle of the hydrogen pressure reducing valve 11 is adjusted in real time according to the pressure feedback of the hydrogen inlet pressure sensor 12, so as to maintain the pressure of the anode side of the fuel cell system to be 150 Kpa.

[0039] In step S3, the pressure of the anode side of the fuel cell system is maintained to be 150 Kpa. The hydrogen tail valve 13 is opened for 0.5 seconds every 1 second. After 3 seconds, the inert gas of the anode side of the fuel cell system is completely discharged.

[0040] In step S4, the opening degrees of the air inlet throttle valve 3 and the air outlet throttle valve 5 are set to 90°.

[0041] In step S5, the rotating speed of the air compressor 2 is set to 30000 rpm. After the rotating speed of the air compressor 2 reaches 30000 rpm, a large amount of air is brought into the cathode side of the fuel cell system. After 2 seconds, the inert gas of the cathode side of the fuel cell system is replaced and discharged, and the system is completed.

[0042] The specific embodiments described herein merely exemplify the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways without departing from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A method for efficient gas replacement at start-up of a fuel cell system, characterized by, The method comprises the following steps: S1, opening the air intake throttle valve (3) of the fuel cell system, closing the air intake throttle valve (3) after the cathode side pressure of the fuel cell system is recovered, thereby increasing the upper limit of the anode side pressure during replacement; S2, adjusting the hydrogen system of the fuel cell system, and maintaining the anode side pressure of the fuel cell system; S3, intermittently opening the hydrogen tail exhaust pipe to discharge the anode side inert gas of the fuel cell system; S4, opening the air intake throttle valve (3) and the air outlet throttle valve (5) of the fuel cell system; S5, starting the air compressor (2), and large flow air enters the cathode side of the fuel cell system to discharge the cathode side inert gas of the fuel cell system, thereby completing the gas replacement. The fuel cell system comprises a stack (8), an air system and a hydrogen system, the air system is used for supplying air to the stack (8), and the hydrogen system is used for supplying hydrogen to the stack (8).

2. The fuel cell system start-up efficient gas replacement method according to claim 1, characterized by, The air system comprises an air compressor (2), an air intake throttle valve (3) and an air outlet throttle valve (5), the air compressor (2) is connected with the cathode inlet of the stack (8) through the air intake throttle valve (3), the cathode outlet of the stack (8) is connected with the air outlet throttle valve (5), and the air system further comprises an air humidifier (4) used for humidifying air.

3. The start-up high-efficiency gas replacement method of a fuel cell system according to claim 2, characterized by, The hydrogen system comprises a hydrogen high-pressure bottle (15), a hydrogen pressure reducing valve (11) and a hydrogen tail exhaust valve (13), the hydrogen high-pressure bottle (15) is connected with the anode inlet of the stack (8) through the hydrogen pressure reducing valve (11), the anode outlet of the stack (8) is connected with the hydrogen tail exhaust valve (13), and the hydrogen system further comprises a hydrogen circulating pump (14) used for circulating hydrogen.

4. The start-up high-efficiency gas replacement method of a fuel cell system according to claim 3, characterized by, The front end of the air compressor (2) is further provided with an air filter (1) used for filtering air, the cathode inlet of the stack (8) is provided with an air inlet stack pressure sensor (6), the cathode outlet of the stack (8) is provided with an air outlet stack pressure sensor (7), and the cathode outlet of the stack (8) is provided with a hydrogen inlet stack pressure sensor (12).

5. The start-up high-efficiency gas replacement method of a fuel cell system according to claim 4, characterized by, In the step S1, the air intake throttle valve (3) of the fuel cell system is opened, the target angle of the air intake throttle valve (3) is set to 10°, and when the air inlet stack pressure sensor (6) detects that the pressure is greater than 100Kap, the target angle of the air intake throttle valve (3) is set to 0°.

6. The start-up high-efficiency gas replacement method of a fuel cell system according to claim 4, characterized by, In the step S2, the hydrogen pressure reducing valve (11) is opened, the opening angle of the hydrogen pressure reducing valve (11) is adjusted in real time according to the pressure feedback of the hydrogen inlet stack pressure sensor (12), and the anode side pressure of the fuel cell system is maintained at 150Kpa.

7. The start-up high-efficiency gas replacement method of a fuel cell system according to claim 4, characterized by, In the step S3, the anode side pressure of the fuel cell system is maintained at 150Kpa, the hydrogen tail exhaust valve (13) is opened for 0.5 seconds every 1 second, and after 3 seconds, the inert gas on the anode side of the fuel cell system can be completely discharged.

8. The start-up efficient gas replacement method of a fuel cell system according to claim 4, characterized by, In the step S4, the opening degrees of the air intake throttle valve (3) and the air outlet throttle valve (5) are set to 90°.

9. The start-up efficient gas replacement method of a fuel cell system according to claim 4, characterized by, The step S5, set the air compressor (2) speed 30000rpm, air compressor (2) speed reaches 30000rpm will bring into a large flow of air into the fuel cell system cathode side, 2 seconds after the fuel cell system cathode side inert gas will be replaced by the displacement, system displacement is completed.

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