A leak diagnosis system for a fuel cell stack and a control method thereof

Abstract

The present application relates to a kind of leak detection diagnostic systems for fuel cell stack, for detecting fuel cell stack air tightness, including hydrogen inlet and exhaust system, hydrogen flow control system, nitrogen inlet and exhaust system, nitrogen flow control system, nitrogen tail exhaust drainage system, air inlet and exhaust system and air flow control system composition, the hydrogen inlet and exhaust system is connected with hydrogen flow control system, the nitrogen inlet and exhaust system, nitrogen flow control system and nitrogen tail exhaust drainage system are sequentially connected, the air inlet and exhaust system is connected with air flow control system, the nitrogen tail exhaust drainage system includes nitrogen tail exhaust high liquid level sensor, nitrogen tail exhaust low liquid level sensor, nitrogen tail exhaust drainage solenoid valve, nitrogen tail exhaust drainage ball valve and water vapor separation tank.Compared with prior art, the present application contains tail exhaust liquid water collection function, with gas, pressure, flow control function simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, in particular to a leak detection diagnosis system for fuel cell stack and a control method thereof. BACKGROUND

[0002] Fuel cell engine as a new type of green power source, because of its high efficiency and low emission and other excellent characteristics, is gradually becoming one of the research focuses of vehicle-mounted engine. Fuel cell engine is based on the output of load, and has good controllability for the whole vehicle; at the same time, the energy output of fuel cell engine is electric energy, which simplifies the transmission and speed regulation structure of traditional automobile. Although fuel cell engine has many advantages compared with internal combustion engine, there are still many problems to be solved before fuel cell engine can replace internal combustion engine as the mainstream of automobile engine. The out-of-factory test process of fuel cell stack is complicated, and there is no rapid diagnosis function for three-cavity series leakage of the stack at present. SUMMARY

[0003] The purpose of the present application is to overcome the defects of the prior art and provide a leak detection diagnosis system for fuel cell stack and a control method thereof. The system realizes the detection of pressure and flow rate between three cavities through a hydrogen inlet and exhaust system, a hydrogen flow control system, a nitrogen inlet and exhaust system, a nitrogen flow control system, a nitrogen tail exhaust drainage system, an air inlet and exhaust system and an air flow control system, and realizes the rapid diagnosis of the stack out of the factory through single voltage detection.

[0004] The purpose of the present application can be achieved by the following technical solutions:

[0005] A leak detection diagnosis system for fuel cell stack for detecting the air tightness of fuel cell stack, comprising a hydrogen inlet and exhaust system, a hydrogen flow control system, a nitrogen inlet and exhaust system, a nitrogen flow control system, a nitrogen tail exhaust drainage system, an air inlet and exhaust system and an air flow control system, the hydrogen inlet and exhaust system is connected with the hydrogen flow control system, the nitrogen inlet and exhaust system, the nitrogen flow control system and the nitrogen tail exhaust drainage system are connected in sequence, the air inlet and exhaust system is connected with the air flow control system,

[0006] The nitrogen tail exhaust drainage system comprises a nitrogen tail exhaust high liquid level sensor, a nitrogen tail exhaust low liquid level sensor, a nitrogen tail exhaust drainage electromagnetic valve, a nitrogen tail exhaust drainage ball valve and a water vapor separation tank,

[0007] The nitrogen tail exhaust high liquid level sensor is connected with the lower end of the water vapor separation tank through a pipeline, the nitrogen tail exhaust low liquid level sensor is connected with the lower end of the water vapor separation tank through a pipeline, the tail exhaust high liquid level sensor is higher than the nitrogen tail exhaust low liquid level sensor, and the nitrogen tail exhaust high liquid level sensor and the nitrogen tail exhaust low liquid level sensor are used for detecting the tail exhaust liquid level;

[0008] The water vapor separation tank is connected to the fuel cell stack at one end, and is connected to the nitrogen tail exhaust drainage electromagnetic valve through a pipeline at the other end. A branch is also led out of the water vapor separation tank and directly connected to the nitrogen tail exhaust drainage ball valve through a pipeline. The nitrogen tail exhaust drainage electromagnetic valve and the nitrogen tail exhaust drainage ball valve are connected to the water outlet through a pipeline. The nitrogen tail exhaust drainage electromagnetic valve is used for automatic control of high liquid level drainage, and the nitrogen tail exhaust drainage ball valve is used for manual drainage after test completion or equipment disassembly.

[0009] Further, a single-chip voltage patrol instrument is arranged on the fuel cell stack, which is used to detect the pressure of each single piece of the fuel cell stack.

[0010] Further, the inlet end of the fuel cell stack is provided with a fuel cell stack hydrogen inlet, a fuel cell stack water inlet and a fuel cell stack air inlet in parallel, and the outlet end of the fuel cell stack is provided with a fuel cell stack hydrogen outlet, a fuel cell stack water outlet and a fuel cell stack air outlet in parallel.

[0011] Further, the hydrogen inlet and exhaust system includes a hydrogen electric pressure regulating valve, a hydrogen pressure gauge, a hydrogen inlet angle seat valve, a hydrogen pressure sensor and a hydrogen exhaust angle seat valve, which are connected in sequence through a pipeline.

[0012] The hydrogen electric pressure regulating valve is used to adjust the inlet pressure.

[0013] The hydrogen pressure gauge is used to detect the inlet pressure.

[0014] The hydrogen inlet angle seat valve is used to control the inlet switch.

[0015] The hydrogen pressure sensor is used to detect the pressure maintaining pressure.

[0016] The hydrogen exhaust angle seat valve is used to control the exhaust switch.

[0017] Further, the hydrogen electric pressure regulating valve is connected to the hydrogen inlet through a pipeline, and the hydrogen exhaust angle seat valve is connected to the hydrogen outlet through a pipeline.

[0018] Further, the hydrogen flow control system includes a hydrogen float flowmeter and a hydrogen mass flowmeter connected in sequence through a pipeline. The hydrogen float flowmeter is connected to the hydrogen pressure sensor through a pipeline, and the hydrogen mass flowmeter is connected to the fuel cell stack hydrogen inlet through a pipeline.

[0019] The hydrogen float flow meter is used for controlling the air intake flow (which can be unmodified after the initial adjustment),

[0020] The hydrogen mass flow meter is used for monitoring the actual flow.

[0021] The nitrogen air intake and exhaust system further comprises a nitrogen electric pressure regulating valve, a nitrogen pressure gauge, a nitrogen air intake angle seat valve, a nitrogen pressure sensor and a nitrogen exhaust angle seat valve, the nitrogen electric pressure regulating valve, the nitrogen pressure gauge, the nitrogen air intake angle seat valve and the nitrogen pressure sensor are connected in sequence through pipelines, the nitrogen exhaust angle seat valve is connected with the water outlet of the fuel cell stack through a pipeline,

[0022] The nitrogen electric pressure regulating valve is used for adjusting the air intake pressure,

[0023] The nitrogen pressure gauge is used for detecting the air intake pressure,

[0024] The nitrogen air intake angle seat valve is used for controlling the air intake switch,

[0025] The nitrogen pressure sensor is used for detecting the pressure maintaining pressure,

[0026] The nitrogen exhaust angle seat valve is used for controlling the exhaust switch.

[0027] The nitrogen electric pressure regulating valve is connected with the nitrogen inlet through a pipeline, the nitrogen exhaust angle seat valve is connected with the water vapor separation tank through a pipeline, and the water vapor separation tank is provided with a nitrogen outlet connected through a pipeline.

[0028] The nitrogen flow control system further comprises a nitrogen float flow meter and a nitrogen mass flow meter connected in sequence through pipelines, the nitrogen float flow meter is connected with the nitrogen pressure sensor through a pipeline, and the nitrogen mass flow meter is connected with the water inlet of the fuel cell stack through a pipeline,

[0029] The nitrogen float flow meter is used for controlling the air intake flow (which can be unmodified after the initial adjustment),

[0030] The nitrogen mass flow meter is used for monitoring the actual flow.

[0031] The air intake and exhaust system further comprises an air electric pressure regulating valve, an air pressure gauge, an air intake angle seat valve, an air pressure sensor and an air exhaust angle seat valve, the air electric pressure regulating valve, the air pressure gauge, the air intake angle seat valve and the air pressure sensor are connected in sequence through pipelines, and the air exhaust angle seat valve is connected with the air outlet of the fuel cell stack through a pipeline,

[0032] The air electric pressure regulating valve is used for adjusting the air intake pressure,

[0033] The air pressure gauge is used for detecting the air intake pressure,

[0034] The air intake angle seat valve is used to control the air intake switch.

[0035] The air pressure sensor is used to detect the holding pressure.

[0036] The air exhaust angle seat valve is used to control the exhaust switch.

[0037] Furthermore, an angle seat valve is provided between the air electric pressure regulating valve and the air pressure gauge. The air electric pressure regulating valve is connected to the air inlet through a pipeline, and the air exhaust angle seat valve is connected to the air outlet through a pipeline.

[0038] Furthermore, the air flow control system includes an air float flow meter and an air mass flow meter connected in sequence via pipes. The air float flow meter is connected to an air pressure sensor via a pipe, and the air mass flow meter is connected to the air inlet of the fuel cell stack via a pipe.

[0039] The air float flow meter is used to control the intake air flow (no modification is required after the initial adjustment).

[0040] The air mass flow meter is used to monitor the actual flow rate.

[0041] Furthermore, the present invention also provides a control method for a leak detection and diagnostic system for fuel cell stacks, the specific steps of which are as follows:

[0042] 1) Hydrogen-air leakage test: Adjust the inlet pressure through the hydrogen, nitrogen, and air electric pressure regulating valves respectively. Open the hydrogen inlet angle seat valve, nitrogen inlet angle seat valve, and air inlet angle seat valve. Hydrogen enters the hydrogen chamber of the fuel cell stack through the hydrogen inlet, air enters the air chamber of the fuel cell stack through the air inlet, and nitrogen enters the water chamber of the fuel cell stack through the water inlet. At this time, the hydrogen exhaust angle seat valve, nitrogen exhaust angle seat valve, and air exhaust angle seat valve are open.

[0043] The voltage value is established by the gas flow of a single cell in the fuel cell stack, and the reactant gas is purged for a sufficient time to fill the fuel cell stack cavity.

[0044] After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve is increased to 50 kPa. After the hydrogen inlet pressure sensor confirms that the pressure has risen to 50 kPa, the hydrogen outlet angle seat valve and the air inlet angle seat valve are closed, and the hydrogen inlet angle seat valve and the air outlet angle seat valve are opened. The purpose of keeping the hydrogen inlet angle seat valve open is that if a cross-leak occurs, the hydrogen reaction will cause the gas pressure to drop from 50 kPa. The purpose of keeping the air outlet angle seat valve open is that if a cross-leak occurs, the oxygen reaction will cause the atmospheric pressure to drop.

[0045] The pressure of each individual cell in the fuel cell stack under test is detected by a single-cell voltage monitor. After a period of time, the voltage difference of each individual cell in the fuel cell stack before and after the pressure is maintained is recorded. If it is higher than the set value, it indicates that there is a leakage between the hydrogen chamber and the air chamber of this cell in the fuel cell stack.

[0046] 2) Hydrogen-water leakage test: Adjust the inlet pressure using the hydrogen, nitrogen, and air electric pressure regulating valves respectively. Open the hydrogen, nitrogen, and air inlet angle valves. Hydrogen enters the hydrogen chamber of the fuel cell stack through the hydrogen inlet, air enters the water chamber of the fuel cell stack through the air inlet, and nitrogen enters the air chamber of the fuel cell stack through the water inlet. At this time, the hydrogen, nitrogen, and air exhaust angle valves are open.

[0047] The voltage value is established by the gas flow of a single cell in the fuel cell stack, and the reactant gas is purged for a sufficient time to fill the fuel cell stack cavity.

[0048] After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve is increased to 180 kPa. After the hydrogen inlet pressure sensor confirms that the pressure has risen to 180 kPa, the hydrogen outlet angle seat valve and the air inlet angle seat valve are closed, and the hydrogen inlet angle seat valve and the air outlet angle seat valve are opened. The purpose of keeping the hydrogen inlet angle seat valve open is that if a cross-leak occurs, the hydrogen reaction will cause the gas pressure to drop from 180 kPa. The purpose of keeping the air outlet angle seat valve open is that if a cross-leak occurs, the oxygen reaction will cause the atmospheric pressure to drop.

[0049] The pressure of each individual cell in the fuel cell stack under test is detected by a single-cell voltage monitor. After a period of time, the voltage difference of each individual cell in the fuel cell stack before and after the pressure is maintained is recorded. If it is higher than the set value, it indicates that there is a leakage between the water chamber and the hydrogen chamber of this cell in the fuel cell stack.

[0050] 3) Air-water leakage test: Adjust the inlet pressure using the hydrogen, nitrogen, and air electric pressure regulating valves respectively. Open the hydrogen, nitrogen, and air inlet valves. Hydrogen enters the water chamber of the fuel cell stack through the hydrogen inlet, air enters the air chamber of the fuel cell stack through the air inlet, and nitrogen enters the hydrogen chamber of the fuel cell stack through the water inlet. At this time, the hydrogen, nitrogen, and air exhaust valves are open.

[0051] The voltage value is established by the gas flow of a single cell in the fuel cell stack, and the reactant gas is purged for a sufficient time to fill the fuel cell stack cavity.

[0052] After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve is increased to 180 kPa. After the hydrogen inlet pressure sensor confirms that the pressure has risen to 180 kPa, the hydrogen outlet angle seat valve and the air inlet angle seat valve are closed, and the hydrogen inlet angle seat valve and the air outlet angle seat valve are opened. The purpose of keeping the hydrogen inlet angle seat valve open is that if a cross-leak occurs, the hydrogen reaction will cause the gas pressure to drop from 180 kPa. The purpose of keeping the air outlet angle seat valve open is that if a cross-leak occurs, the oxygen reaction will cause the atmospheric pressure to drop.

[0053] The pressure of each individual cell in the fuel cell stack under test is detected by a single-cell voltage monitor. After a period of time, the voltage difference of each individual cell in the fuel cell stack before and after the pressure is maintained is recorded. If it is higher than the set value, it indicates that there is a leakage between the water cavity and the air cavity of this cell in the fuel cell stack.

[0054] Furthermore, depending on the fuel cell stack, the purging time ranges from approximately 60 to 120 seconds.

[0055] Furthermore, the detection time of the single-chip voltage inspection instrument varies depending on the fuel cell stack, and is specifically based on the actual situation of the stack under test.

[0056] Furthermore, the set value varies depending on the different difference requirements of the fuel cell stack, specifically according to the actual situation of the stack under test.

[0057] The working principle of this invention is as follows:

[0058] The hydrogen electric pressure regulating valve is used to adjust different inlet pressures. The pressure value after depressurization is confirmed by the hydrogen pressure gauge. When hydrogen supply needs to be started, the hydrogen inlet angle seat valve is opened. When overall pressure holding is required, the hydrogen inlet angle seat valve and the hydrogen exhaust angle seat valve are closed. When pressure relief is required, the hydrogen exhaust angle seat valve is opened.

[0059] The nitrogen electric pressure regulating valve is used to adjust different inlet pressures. The pressure value after pressure reduction is confirmed by the nitrogen pressure gauge. When nitrogen supply needs to be started, the nitrogen inlet angle seat valve is opened. When overall pressure holding is required, the nitrogen inlet angle seat valve and the nitrogen exhaust angle seat valve are closed. When pressure relief is required, the nitrogen exhaust angle seat valve is opened.

[0060] The electric air pressure regulating valve is used to adjust different intake pressures. The pressure value after depressurization is confirmed by the air pressure gauge. When it is necessary to start the air supply, the air intake angle seat valve is opened. When it is necessary to maintain the overall pressure, the air intake angle seat valve and the air exhaust angle seat valve are closed. When it is necessary to release pressure, the air exhaust angle seat valve is opened.

[0061] Nitrogen is usually connected to the fuel cell stack water circuit first, so the fuel cell stack water chamber contains liquid water. After the high liquid level sensor of nitrogen tail discharge detects water, the nitrogen tail discharge drain solenoid valve opens to drain the water. The low liquid level sensor of nitrogen tail discharge is used to confirm the seal.

[0062] In actual testing, hydrogen flows through the hydrogen chamber, air flows through the air chamber, and nitrogen flows through the water passage chamber of the fuel cell stack. Each fuel cell stack cell will establish a voltage value due to the gas flow. The reactant gases are purged for a sufficient time to fill the fuel cell stack chamber. Then, the hydrogen outlet is closed, the pressure is maintained at 50 kPa, the air supply is cut off, and this process is continued for a period of time. The voltage difference of each cell before and after the pressure maintenance is recorded. If it is higher than a certain value, then there is a hydrogen-air leakage phenomenon in this cell.

[0063] This device can connect to different chambers via various pipelines to simultaneously perform hydrogen-water and air-water leakage tests. For example, hydrogen flows through the water path, and air flows through the air path. After the hydrogen path is purged with nitrogen and allowed to stand, hydrogen and air are purged to ensure that the chamber is filled with reactive gases. The water path is pressurized to 180 kPa (hydrogen), and air is continuously supplied for a period of time. The difference in pressure change of all individual components from the start of purging to the end of pressurization is calculated. If the difference exceeds a certain set value, the component is discarded, indicating that there is a hydrogen-water leakage.

[0064] Specific parameters and holding time can be set by the user according to different performance fuel cells.

[0065] Compared with the prior art, the present invention provides a leak detection and diagnostic system for fuel cell stacks, which includes a tailpipe liquid water collection function and gas, pressure and flow control functions. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of a leak detection and diagnostic system for fuel cell stacks.

[0067] Reference numerals: 101. Hydrogen electric pressure regulating valve; 102. Hydrogen pressure gauge; 103. Hydrogen inlet angle seat valve; 104. Hydrogen pressure sensor; 105. Hydrogen float flow meter; 106. Hydrogen mass flow meter; 107. Hydrogen exhaust angle seat valve; 108. Hydrogen inlet; 109. Hydrogen outlet; 201. Nitrogen electric pressure regulating valve; 202. Nitrogen pressure gauge; 203. Nitrogen inlet angle seat valve; 204. Nitrogen pressure sensor; 205. Nitrogen float flow meter; 206. Nitrogen mass flow meter; 207. Nitrogen exhaust angle seat valve; 208. Nitrogen tail discharge high level sensor; 209. Nitrogen tail discharge low level sensor; 210. Nitrogen tail discharge drain solenoid valve; 211. Nitrogen tail discharge drain ball valve; 2 12. Nitrogen inlet; 213. Nitrogen outlet; 214. Water vapor separator; 301. Electric air pressure regulating valve; 302. Air pressure gauge; 303. Air inlet angle seat valve; 304. Air pressure sensor; 305. Air float flow meter; 306. Air mass flow meter; 307. Air exhaust angle seat valve; 308. Air inlet; 309. Air outlet; 310. Angle seat valve; 401. Single-chip voltage monitoring instrument; 5. Fuel cell stack; 501. Fuel cell stack hydrogen inlet; 502. Fuel cell stack hydrogen outlet; 503. Fuel cell stack water inlet; 504. Fuel cell stack water outlet; 505. Fuel cell stack air inlet; 506. Fuel cell stack air outlet. Detailed Implementation

[0068] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0069] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0070] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] Example

[0072] refer to Figure 1 This embodiment provides a leak detection and diagnostic system for fuel cell stacks, used to detect the airtightness of the fuel cell stack 5. It comprises a hydrogen intake and exhaust system, a hydrogen flow control system, a nitrogen intake and exhaust system, a nitrogen flow control system, a nitrogen exhaust drainage system, an air intake and exhaust system, and an air flow control system. The hydrogen intake and exhaust system is connected to the hydrogen flow control system. The nitrogen intake and exhaust system, the nitrogen flow control system, and the nitrogen exhaust drainage system are sequentially connected. The air intake and exhaust system is connected to the air flow control system.

[0073] The nitrogen tail discharge drainage system includes a nitrogen tail discharge high level sensor 208, a nitrogen tail discharge low level sensor 209, a nitrogen tail discharge drainage solenoid valve 210, a nitrogen tail discharge drainage ball valve 211, and a water vapor separator 214.

[0074] The nitrogen exhaust high liquid level sensor 208 is connected to the lower end of the water vapor separator 214 via a pipe, and the nitrogen exhaust low liquid level sensor 209 is connected to the lower end of the water vapor separator 214 via a pipe. The exhaust high liquid level sensor 208 is higher than the nitrogen exhaust low liquid level sensor 209. The nitrogen exhaust high liquid level sensor 208 and the nitrogen exhaust low liquid level sensor 209 are used to detect the exhaust liquid level.

[0075] One end of the water vapor separator 214 is connected to the fuel cell stack 5, and the other end of the water vapor separator 214 is connected to the nitrogen tail discharge solenoid valve 210 through a pipeline. A branch line is also led out from the water vapor separator 214 and directly connected to the nitrogen tail discharge ball valve 211 through a pipeline. The nitrogen tail discharge solenoid valve 210 and the nitrogen tail discharge ball valve 211 are connected to the water outlet through a pipeline. The nitrogen tail discharge solenoid valve 210 is used to automatically control high liquid level drainage, and the nitrogen tail discharge ball valve 211 is used for manual drainage after the test is completed or the equipment is disassembled.

[0076] Furthermore, the fuel cell stack 5 is equipped with a single-piece voltage inspector 401, which is used to detect the pressure of each single piece of the fuel cell stack 5 under test.

[0077] Furthermore, the inlet end of the fuel cell stack 5 is provided with a fuel cell stack hydrogen inlet 501, a fuel cell stack water inlet 503 and a fuel cell stack air inlet 505 connected in parallel, and the outlet end of the fuel cell stack 5 is provided with a fuel cell stack hydrogen outlet 502, a fuel cell stack water outlet 504 and a fuel cell stack air outlet 506 connected in parallel.

[0078] Furthermore, the hydrogen intake and exhaust system includes a hydrogen electric pressure regulating valve 101, a hydrogen pressure gauge 102, a hydrogen intake angle seat valve 103, a hydrogen pressure sensor 104, and a hydrogen exhaust angle seat valve 107. The hydrogen electric pressure regulating valve 101, hydrogen pressure gauge 102, hydrogen intake angle seat valve 103, and hydrogen pressure sensor 104 are connected sequentially via pipelines. The hydrogen exhaust angle seat valve 107 is connected to the hydrogen outlet 502 of the fuel cell stack via a pipeline.

[0079] The hydrogen electric pressure regulating valve 101 is used to regulate the inlet pressure.

[0080] The hydrogen pressure gauge 102 is used to detect the inlet pressure.

[0081] The hydrogen inlet angle seat valve 103 is used to control the inlet switch.

[0082] The hydrogen pressure sensor 104 is used to detect the holding pressure.

[0083] The hydrogen exhaust angle seat valve 107 is used to control the exhaust switch.

[0084] Furthermore, the hydrogen electric pressure regulating valve 101 is connected to the hydrogen inlet 108 via a pipeline, and the hydrogen exhaust angle seat valve 107 is connected to the hydrogen outlet 109 via a pipeline.

[0085] Furthermore, the hydrogen flow control system includes a hydrogen float flow meter 105 and a hydrogen mass flow meter 106 connected in sequence via pipelines. The hydrogen float flow meter 105 is connected to a hydrogen pressure sensor 104 via a pipeline, and the hydrogen mass flow meter 106 is connected to the hydrogen inlet 501 of the fuel cell stack via a pipeline.

[0086] The hydrogen float flowmeter 105 is used to control the intake flow rate (no modification is required after the initial adjustment).

[0087] The hydrogen mass flow meter 106 is used to monitor the actual flow rate.

[0088] Furthermore, the nitrogen intake and exhaust system includes a nitrogen electric pressure regulating valve 201, a nitrogen pressure gauge 202, a nitrogen intake angle seat valve 203, a nitrogen pressure sensor 204, and a nitrogen exhaust angle seat valve 207. The nitrogen electric pressure regulating valve 201, nitrogen pressure gauge 202, nitrogen intake angle seat valve 203, and nitrogen pressure sensor 204 are connected sequentially via pipes. The nitrogen exhaust angle seat valve 207 is connected to the fuel cell stack water outlet 504 via a pipe.

[0089] The nitrogen electric pressure regulating valve 201 is used to regulate the inlet pressure.

[0090] The nitrogen pressure gauge 202 is used to detect the intake pressure.

[0091] The nitrogen inlet angle seat valve 203 is used to control the inlet switch.

[0092] The nitrogen pressure sensor 204 is used to detect the holding pressure.

[0093] The nitrogen exhaust angle seat valve 207 is used to control the exhaust switch.

[0094] Furthermore, the nitrogen electric pressure regulating valve 201 is connected to the nitrogen inlet 212 via a pipeline, the nitrogen exhaust angle seat valve 207 is connected to the water vapor separator 214 via a pipeline, and the upper end of the water vapor separator 214 is provided with a nitrogen outlet 213 connected via a pipeline.

[0095] Furthermore, the nitrogen flow control system includes a nitrogen float flow meter 205 and a nitrogen mass flow meter 206 connected in sequence via pipes. The nitrogen float flow meter 205 is connected to a nitrogen pressure sensor 204 via a pipe, and the nitrogen mass flow meter 206 is connected to the fuel cell stack water inlet 503 via a pipe.

[0096] The nitrogen float flowmeter 205 is used to control the intake flow rate (no modification is required after the initial adjustment).

[0097] The nitrogen mass flow meter 206 is used to monitor the actual flow rate.

[0098] Furthermore, the air intake and exhaust system includes an electric air pressure regulating valve 301, an air pressure gauge 302, an air intake angle seat valve 303, an air pressure sensor 304, and an air exhaust angle seat valve 307. The electric air pressure regulating valve 301, air pressure gauge 302, air intake angle seat valve 303, and air pressure sensor 304 are connected sequentially via pipes. The air exhaust angle seat valve 307 is connected to the air outlet 506 of the fuel cell stack via a pipe.

[0099] The electric air pressure regulating valve 301 is used to regulate the intake air pressure.

[0100] The air pressure gauge 302 is used to detect the intake pressure.

[0101] The air intake angle seat valve 303 is used to control the air intake switch.

[0102] The air pressure sensor 304 is used to detect the holding pressure.

[0103] The air exhaust angle seat valve 307 is used to control the exhaust switch.

[0104] Furthermore, an angle seat valve 310 is provided between the air electric pressure regulating valve 301 and the air pressure gauge 302. The air electric pressure regulating valve 301 is connected to the air inlet 308 through a pipeline, and the air exhaust angle seat valve 307 is connected to the air outlet 309 through a pipeline.

[0105] Furthermore, the air flow control system includes an air float flow meter 305 and an air mass flow meter 306 connected in sequence via pipes. The air float flow meter 305 is connected to an air pressure sensor 304 via a pipe, and the air mass flow meter 306 is connected to the air inlet 505 of the fuel cell stack via a pipe.

[0106] The air float flowmeter 305 is used to control the intake air flow (no modification is required after the initial adjustment).

[0107] The air mass flow meter 306 is used to monitor the actual flow rate.

[0108] Furthermore, the present invention also provides a control method for a leak detection and diagnostic system for fuel cell stacks, the specific steps of which are as follows:

[0109] 1) Hydrogen-air leakage test: The intake pressure is adjusted by the hydrogen electric pressure regulating valve 101, nitrogen electric pressure regulating valve 201 and air electric pressure regulating valve 301 respectively. The hydrogen intake angle seat valve 103, nitrogen intake angle seat valve 203 and air intake angle seat valve 303 are opened. Hydrogen enters the hydrogen chamber of fuel cell stack 5 through the hydrogen inlet 501 of fuel cell stack. Air enters the air chamber of fuel cell stack 5 through the air inlet 505 of fuel cell stack. Nitrogen enters the water chamber of fuel cell stack 5 through the water inlet 503 of fuel cell stack. At this time, the hydrogen exhaust angle seat valve 107, nitrogen exhaust angle seat valve 207 and air exhaust angle seat valve 307 are opened.

[0110] The voltage value is established by the gas flow of the fuel cell stack 5 single piece, and the reaction gas is purged for a sufficient time to fill the chamber of the fuel cell stack 5.

[0111] After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve 101 is increased to 50 kPa. After the hydrogen inlet pressure sensor 104 confirms that the pressure has risen to 50 kPa, the hydrogen outlet angle seat valve 107 and the air inlet angle seat valve 303 are closed, and the hydrogen inlet angle seat valve 103 and the air outlet angle seat valve 307 are opened. The purpose of keeping the hydrogen inlet angle seat valve 103 open is that if a leakage occurs, the hydrogen reaction will cause the gas pressure to drop from 50 kPa. The purpose of keeping the air outlet angle seat valve 307 open is that if a leakage occurs, the oxygen reaction will cause the atmospheric pressure to drop.

[0112] The single-piece voltage inspection instrument 401 detects the pressure of each piece of the fuel cell stack 5 under test. After a period of time, the voltage difference of each piece of the fuel cell stack 5 before and after the pressure is maintained is recorded. If it is higher than the set value, it means that there is a leakage between the hydrogen chamber and the air chamber of this piece of the fuel cell stack 5.

[0113] 2) Hydrogen-water leakage test: Adjust the inlet pressure through the hydrogen electric pressure regulating valve 101, nitrogen electric pressure regulating valve 201 and air electric pressure regulating valve 301 respectively. Open the hydrogen inlet angle seat valve 103, nitrogen inlet angle seat valve 203 and air inlet angle seat valve 303. Hydrogen enters the hydrogen chamber of fuel cell stack 5 through the hydrogen inlet 501 of fuel cell stack. Air enters the water chamber of fuel cell stack 5 through the air inlet 505 of fuel cell stack. Nitrogen enters the air chamber of fuel cell stack 5 through the water inlet 503 of fuel cell stack. At this time, the hydrogen exhaust angle seat valve 107, nitrogen exhaust angle seat valve 207 and air exhaust angle seat valve 307 are opened.

[0114] The voltage value is established by the gas flow of the fuel cell stack 5 single piece, and the reaction gas is purged for a sufficient time to fill the chamber of the fuel cell stack 5.

[0115] After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve 101 is increased to 180 kPa. After the hydrogen inlet pressure sensor 104 confirms that the pressure has risen to 180 kPa, the hydrogen outlet angle seat valve 107 and the air inlet angle seat valve 303 are closed, and the hydrogen inlet angle seat valve 103 and the air outlet angle seat valve 307 are opened. The purpose of keeping the hydrogen inlet angle seat valve 103 open is that if a leakage occurs, the hydrogen reaction will cause the gas pressure to drop from 180 kPa. The purpose of keeping the air outlet angle seat valve 307 open is that if a leakage occurs, the oxygen reaction will cause the atmospheric pressure to drop.

[0116] The single-piece voltage inspection instrument 401 detects the pressure of each piece of the fuel cell stack 5 under test. After a period of time, the voltage difference of each piece of the fuel cell stack 5 before and after the pressure is maintained is recorded. If it is higher than the set value, it means that there is a leakage between the water chamber and the hydrogen chamber of this piece of the fuel cell stack 5.

[0117] 3) Air-water leakage test: Adjust the inlet pressure through the hydrogen electric pressure regulating valve 101, nitrogen electric pressure regulating valve 201 and air electric pressure regulating valve 301 respectively. Open the hydrogen inlet angle seat valve 103, nitrogen inlet angle seat valve 203 and air inlet angle seat valve 303. Hydrogen enters the water chamber of fuel cell stack 5 through the hydrogen inlet 501 of fuel cell stack. Air enters the air chamber of fuel cell stack 5 through the air inlet 505 of fuel cell stack. Nitrogen enters the hydrogen chamber of fuel cell stack 5 through the water inlet 503 of fuel cell stack. At this time, the hydrogen exhaust angle seat valve 107, nitrogen exhaust angle seat valve 207 and air exhaust angle seat valve 307 are opened.

[0118] The voltage value is established by the gas flow of the fuel cell stack 5 single piece, and the reaction gas is purged for a sufficient time to fill the chamber of the fuel cell stack 5.

[0119] After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve 101 is increased to 180 kPa. After the hydrogen inlet pressure sensor 104 confirms that the pressure has risen to 180 kPa, the hydrogen outlet angle seat valve 107 and the air inlet angle seat valve 303 are closed, and the hydrogen inlet angle seat valve 103 and the air outlet angle seat valve 307 are opened. The purpose of keeping the hydrogen inlet angle seat valve 103 open is that if a leakage occurs, the hydrogen reaction will cause the gas pressure to drop from 180 kPa. The purpose of keeping the air outlet angle seat valve 307 open is that if a leakage occurs, the oxygen reaction will cause the atmospheric pressure to drop.

[0120] The single-piece voltage inspector 401 detects the pressure of each piece of the fuel cell stack 5 under test. After a period of time, the voltage difference of each piece of the fuel cell stack 5 before and after the pressure is maintained is recorded. If it is higher than the set value, it means that there is a leakage between the water cavity and the air cavity of this piece of the fuel cell stack 5.

[0121] Furthermore, depending on the fuel cell stack, the purging time ranges from approximately 60 to 120 seconds.

[0122] Furthermore, the detection time of the single-chip voltage inspection instrument 401 varies depending on the fuel cell stack 5, and is specifically based on the actual situation of the tested component stack 5.

[0123] Furthermore, the set value varies depending on the different difference requirements of the fuel cell stack 5, specifically according to the actual situation of the fuel cell stack 5 under test.

[0124] The working principle of this invention is as follows:

[0125] The hydrogen electric pressure regulating valve 101 is used to adjust different inlet pressures. The pressure value after pressure reduction is confirmed by the hydrogen pressure gauge 102. When hydrogen supply needs to be started, the hydrogen inlet angle seat valve 103 is opened. When overall pressure maintenance is needed, the hydrogen inlet angle seat valve 103 and the hydrogen exhaust angle seat valve 107 are closed. When pressure relief is needed, the hydrogen exhaust angle seat valve 107 is opened.

[0126] The nitrogen electric pressure regulating valve 201 is used to adjust different inlet pressures. The pressure value after pressure reduction is confirmed by the nitrogen pressure gauge 202. When nitrogen supply needs to be started, the nitrogen inlet angle seat valve 203 is opened. When overall pressure holding is required, the nitrogen inlet angle seat valve 203 and the nitrogen exhaust angle seat valve 207 are closed. When pressure relief is required, the nitrogen exhaust angle seat valve 207 is opened.

[0127] The electric air pressure regulating valve 301 is used to adjust different intake pressures. The pressure value after pressure reduction is confirmed by the air pressure gauge 302. When it is necessary to start the air supply, the air intake angle seat valve 303 is opened. When it is necessary to maintain the overall pressure, the air intake angle seat valve 303 and the air exhaust angle seat valve 307 are closed. When it is necessary to release pressure, the air exhaust angle seat valve 307 is opened.

[0128] Nitrogen is usually first connected to the water circuit of fuel cell stack 5, so the water chamber of fuel cell stack 5 contains liquid water. After the nitrogen tail discharge high liquid level sensor 208 detects water, the nitrogen tail discharge drain solenoid valve 210 opens to drain water, and the nitrogen tail discharge low liquid level sensor 209 is used to confirm the seal.

[0129] During actual testing, hydrogen flows through the hydrogen chamber, air flows through the air chamber, and nitrogen flows through the water chamber of fuel cell stack 5. Each cell of fuel cell stack 5 will establish a voltage value due to the gas flow. The reaction gas is purged for a sufficient time to fill the chamber of fuel cell stack 5. Then, the hydrogen outlet 502 is closed, the pressure is maintained at 50 kPa, the air supply is cut off, and this process is continued for a period of time. The voltage difference of each cell before and after the pressure maintenance is recorded. If it is higher than a certain value, then there is a hydrogen-air leakage phenomenon in this cell.

[0130] This device can connect to different chambers via various pipelines to simultaneously perform hydrogen-water and air-water leakage tests. For example, hydrogen flows through the water path, and air flows through the air path. After the hydrogen path is purged with nitrogen and allowed to stand, hydrogen and air are purged to ensure that the chamber is filled with reactive gases. The water path is pressurized to 180 kPa (hydrogen), and air is continuously supplied for a period of time. The difference in pressure change of all individual components from the start of purging to the end of pressurization is calculated. If the difference exceeds a certain set value, the component is discarded, indicating that there is a hydrogen-water leakage.

[0131] Specific parameters and holding time can be set by the user according to different performance fuel cells.

[0132] 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 leak detection and diagnostic system for a fuel cell stack, used to detect the airtightness of a fuel cell stack (5), characterized in that, It comprises a hydrogen intake and exhaust system, a hydrogen flow control system, a nitrogen intake and exhaust system, a nitrogen flow control system, a nitrogen exhaust drainage system, an air intake and exhaust system, and an air flow control system. The hydrogen intake and exhaust system is connected to the hydrogen flow control system. The nitrogen intake and exhaust system, the nitrogen flow control system, and the nitrogen exhaust drainage system are sequentially connected. The air intake and exhaust system is connected to the air flow control system. The nitrogen tail discharge drainage system includes a nitrogen tail discharge high level sensor (208), a nitrogen tail discharge low level sensor (209), a nitrogen tail discharge drainage solenoid valve (210), a nitrogen tail discharge drainage ball valve (211), and a water vapor separator (214). The nitrogen exhaust high liquid level sensor (208) is connected to the lower end of the water vapor separator (214) via a pipe, and the nitrogen exhaust low liquid level sensor (209) is connected to the lower end of the water vapor separator (214) via a pipe. The nitrogen exhaust high liquid level sensor (208) is higher than the nitrogen exhaust low liquid level sensor (209). The nitrogen exhaust high liquid level sensor (208) and the nitrogen exhaust low liquid level sensor (209) are used to detect the exhaust liquid level. One end of the water vapor separator (214) is connected to the fuel cell stack (5), and the other end of the water vapor separator (214) is connected to the nitrogen tail discharge solenoid valve (210) through a pipe. A branch line is also led out from the water vapor separator (214) and directly connected to the nitrogen tail discharge ball valve (211) through a pipe. The nitrogen tail discharge solenoid valve (210) and the nitrogen tail discharge ball valve (211) are connected to the water outlet through a pipe. The nitrogen tail discharge solenoid valve (210) is used to automatically control high liquid level drainage, and the nitrogen tail discharge ball valve (211) is used to manually drain water after the test is completed or the equipment is disassembled. The fuel cell stack (5) is equipped with a single-plate voltage inspection instrument (401), which is used to detect the pressure of each single plate of the fuel cell stack (5) under test.

2. The leak detection and diagnostic system for a fuel cell stack according to claim 1, characterized in that, The fuel cell stack (5) has a hydrogen inlet (501), a water inlet (503), and an air inlet (505) connected in parallel at its inlet end, and a hydrogen outlet (502), a water outlet (504), and an air outlet (506) connected in parallel at its outlet end.

3. The leak detection and diagnostic system for a fuel cell stack according to claim 2, characterized in that, The hydrogen intake and exhaust system includes a hydrogen electric pressure regulating valve (101), a hydrogen pressure gauge (102), a hydrogen intake angle seat valve (103), a hydrogen pressure sensor (104), and a hydrogen exhaust angle seat valve (107). The hydrogen electric pressure regulating valve (101), hydrogen pressure gauge (102), hydrogen intake angle seat valve (103), and hydrogen pressure sensor (104) are connected in sequence via pipelines. The hydrogen exhaust angle seat valve (107) is connected to the hydrogen outlet (502) of the fuel cell stack via a pipeline. The hydrogen electric pressure regulating valve (101) is used to regulate the inlet pressure. The hydrogen pressure gauge (102) is used to detect the inlet pressure. The hydrogen inlet angle seat valve (103) is used to control the inlet switch. The hydrogen pressure sensor (104) is used to detect the holding pressure. The hydrogen exhaust angle seat valve (107) is used to control the exhaust switch; The hydrogen electric pressure regulating valve (101) is connected to the hydrogen inlet (108) via a pipeline, and the hydrogen exhaust angle seat valve (107) is connected to the hydrogen outlet (109) via a pipeline.

4. The leak detection and diagnostic system for a fuel cell stack according to claim 3, characterized in that, The hydrogen flow control system includes a hydrogen float flow meter (105) and a hydrogen mass flow meter (106) connected in sequence by pipes. The hydrogen float flow meter (105) is connected to a hydrogen pressure sensor (104) by a pipe, and the hydrogen mass flow meter (106) is connected to the hydrogen inlet (501) of the fuel cell stack by a pipe. The hydrogen float flowmeter (105) is used to control the intake flow rate. The hydrogen mass flow meter (106) is used to monitor the actual flow rate.

5. A leak detection and diagnostic system for a fuel cell stack according to claim 2, characterized in that, The nitrogen intake and exhaust system includes a nitrogen electric pressure regulating valve (201), a nitrogen pressure gauge (202), a nitrogen intake angle seat valve (203), a nitrogen pressure sensor (204), and a nitrogen exhaust angle seat valve (207). The nitrogen electric pressure regulating valve (201), nitrogen pressure gauge (202), nitrogen intake angle seat valve (203), and nitrogen pressure sensor (204) are connected in sequence via pipelines. The nitrogen exhaust angle seat valve (207) is connected to the fuel cell stack water outlet (504) via a pipeline. The nitrogen electric pressure regulating valve (201) is used to regulate the intake pressure. The nitrogen pressure gauge (202) is used to detect the intake pressure. The nitrogen inlet angle seat valve (203) is used to control the inlet switch. The nitrogen pressure sensor (204) is used to detect the holding pressure. The nitrogen exhaust angle seat valve (207) is used to control the exhaust switch; The nitrogen electric pressure regulating valve (201) is connected to the nitrogen inlet (212) through a pipeline, and the nitrogen exhaust angle seat valve (207) is connected to the water vapor separator (214) through a pipeline. The upper end of the water vapor separator (214) is provided with a nitrogen outlet (213) connected through a pipeline.

6. A leak detection and diagnostic system for a fuel cell stack according to claim 5, characterized in that, The nitrogen flow control system includes a nitrogen float flow meter (205) and a nitrogen mass flow meter (206) connected in sequence by pipes. The nitrogen float flow meter (205) is connected to a nitrogen pressure sensor (204) by a pipe, and the nitrogen mass flow meter (206) is connected to the fuel cell stack water inlet (503) by a pipe. The nitrogen float flowmeter (205) is used to control the intake flow rate. The nitrogen mass flow meter (206) is used to monitor the actual flow rate.

7. A leak detection and diagnostic system for a fuel cell stack according to claim 2, characterized in that, The air intake and exhaust system includes an electric air pressure regulating valve (301), an air pressure gauge (302), an air intake angle seat valve (303), an air pressure sensor (304), and an air exhaust angle seat valve (307). The electric air pressure regulating valve (301), air pressure gauge (302), air intake angle seat valve (303), and air pressure sensor (304) are connected in sequence via pipes. The air exhaust angle seat valve (307) is connected to the air outlet (506) of the fuel cell stack via a pipe. The electric air pressure regulating valve (301) is used to regulate the intake air pressure. The air pressure gauge (302) is used to detect the intake pressure. The air intake angle seat valve (303) is used to control the air intake switch. The air pressure sensor (304) is used to detect the holding pressure. The air exhaust angle seat valve (307) is used to control the exhaust switch; An angle seat valve (310) is provided between the air electric pressure regulating valve (301) and the air pressure gauge (302). The air electric pressure regulating valve (301) is connected to the air inlet (308) through a pipe, and the air exhaust angle seat valve (307) is connected to the air outlet (309) through a pipe.

8. A leak detection and diagnostic system for a fuel cell stack according to claim 7, characterized in that, The air flow control system includes an air float flow meter (305) and an air mass flow meter (306) connected in sequence by pipes. The air float flow meter (305) is connected to an air pressure sensor (304) by a pipe, and the air mass flow meter (306) is connected to the air inlet (505) of the fuel cell stack by a pipe. The air float flow meter (305) is used to control the intake air flow. The air mass flow meter (306) is used to monitor the actual flow rate.

9. A control method for a leak detection and diagnostic system for a fuel cell stack according to any one of claims 1-8, characterized in that, The specific steps are as follows: 1) Hydrogen-air leakage test: The intake pressure is adjusted by the hydrogen electric pressure regulating valve (101), nitrogen electric pressure regulating valve (201) and air electric pressure regulating valve (301) respectively. The hydrogen intake angle seat valve (103), nitrogen intake angle seat valve (203) and air intake angle seat valve (303) are opened. Hydrogen enters the hydrogen chamber of the fuel cell stack (5) through the hydrogen inlet (501) of the fuel cell stack. Air enters the air chamber of the fuel cell stack (5) through the air inlet (505) of the fuel cell stack. Nitrogen enters the water chamber of the fuel cell stack (5) through the water inlet (503) of the fuel cell stack. At this time, the hydrogen exhaust angle seat valve (107), nitrogen exhaust angle seat valve (207) and air exhaust angle seat valve (307) are opened. The voltage value of the fuel cell stack (5) is established by the gas flow, and the reaction gas is purged for a sufficient time to fill the cavity of the fuel cell stack (5); After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve (101) is increased to 50 kPa. After the hydrogen inlet pressure sensor (104) confirms that the pressure has risen to 50 kPa, the hydrogen exhaust angle seat valve (107) and the air inlet angle seat valve (303) are closed, and the hydrogen inlet angle seat valve (103) and the air exhaust angle seat valve (307) are opened. The purpose of keeping the hydrogen inlet angle seat valve (103) open is that if a leakage occurs, the hydrogen reaction will cause the gas pressure to drop from 50 kPa. The purpose of keeping the air exhaust angle seat valve (307) open is that if a leakage occurs, the oxygen reaction will cause the atmospheric pressure to drop. The pressure of each piece of the fuel cell stack (5) under test is detected by the single-piece voltage inspection instrument (401). After a period of time, the voltage difference of each piece of the fuel cell stack (5) before and after the pressure is maintained is recorded. If it is higher than the set value, it means that there is a leakage between the hydrogen chamber and the air chamber of this piece of the fuel cell stack (5). 2) Hydrogen-water leakage test: The intake pressure is adjusted by the hydrogen electric pressure regulating valve (101), nitrogen electric pressure regulating valve (201) and air electric pressure regulating valve (301) respectively. The hydrogen intake angle seat valve (103), nitrogen intake angle seat valve (203) and air intake angle seat valve (303) are opened. Hydrogen enters the hydrogen chamber of the fuel cell stack (5) through the hydrogen inlet (501) of the fuel cell stack. Air enters the water chamber of the fuel cell stack (5) through the air inlet (505) of the fuel cell stack. Nitrogen enters the air chamber of the fuel cell stack (5) through the water inlet (503) of the fuel cell stack. At this time, the hydrogen exhaust angle seat valve (107), nitrogen exhaust angle seat valve (207) and air exhaust angle seat valve (307) are opened. The voltage value of the fuel cell stack (5) is established by the gas flow, and the reaction gas is purged for a sufficient time to fill the cavity of the fuel cell stack (5); After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve (101) is increased to 180 kPa. After the hydrogen inlet pressure sensor (104) confirms that the pressure has risen to 180 kPa, the hydrogen exhaust angle seat valve (107) and the air inlet angle seat valve (303) are closed, and the hydrogen inlet angle seat valve (103) and the air exhaust angle seat valve (307) are opened. The purpose of keeping the hydrogen inlet angle seat valve (103) open is that if a leakage occurs, the hydrogen reaction will cause the gas pressure to drop from 180 kPa. The purpose of keeping the air exhaust angle seat valve (307) open is that if a leakage occurs, the oxygen reaction will cause the atmospheric pressure to drop. The pressure of each piece of the fuel cell stack (5) under test is detected by the single-piece voltage inspection instrument (401). After a period of time, the voltage difference of each piece of the fuel cell stack (5) before and after pressure holding is recorded. If it is higher than the set value, it means that there is a leakage between the water chamber and the hydrogen chamber of this piece of the fuel cell stack (5). 3) Air-water leakage test: Adjust the intake pressure by using the hydrogen electric pressure regulating valve (101), nitrogen electric pressure regulating valve (201) and air electric pressure regulating valve (301) respectively. Open the hydrogen intake angle seat valve (103), nitrogen intake angle seat valve (203) and air intake angle seat valve (303). Hydrogen enters the water chamber of the fuel cell stack (5) through the hydrogen inlet (501) of the fuel cell stack. Air enters the air chamber of the fuel cell stack (5) through the air inlet (505) of the fuel cell stack. Nitrogen enters the hydrogen chamber of the fuel cell stack (5) through the water inlet (503) of the fuel cell stack. At this time, the hydrogen exhaust angle seat valve (107), nitrogen exhaust angle seat valve (207) and air exhaust angle seat valve (307) are opened. The voltage value of the fuel cell stack (5) is established by the gas flow, and the reaction gas is purged for a sufficient time to fill the cavity of the fuel cell stack (5); After purging, the inlet pressure of the controlled hydrogen electric pressure regulating valve (101) is increased to 180 kPa. After the hydrogen inlet pressure sensor (104) confirms that the pressure has risen to 180 kPa, the hydrogen exhaust angle seat valve (107) and the air inlet angle seat valve (303) are closed, and the hydrogen inlet angle seat valve (103) and the air exhaust angle seat valve (307) are opened. The purpose of keeping the hydrogen inlet angle seat valve (103) open is that if a leakage occurs, the hydrogen reaction will cause the gas pressure to drop from 180 kPa. The purpose of keeping the air exhaust angle seat valve (307) open is that if a leakage occurs, the oxygen reaction will cause the atmospheric pressure to drop. The pressure of each piece of the fuel cell stack (5) under test is detected by a single-piece voltage inspection instrument (401). After a period of time, the voltage difference of each piece of the fuel cell stack (5) before and after pressure holding is recorded. If it is higher than the set value, it means that there is a leakage between the water cavity and the air cavity of this piece of the fuel cell stack (5).

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