Electric pile leakage detection system and detection method

Abstract

The invention relates to the technical field of fuel cell detection, and particularly provides an electric pile leakage detection system and detection method. The leakage rate detection system comprises a gas supply unit, inflation branches respectively communicated between each chamber of a fuel cell stack core and the gas supply unit, and a flow detection unit, the flow detection unit is connected with a plurality of flowmeters in series, the measuring ranges of the flowmeters are gradually increased, the detection gas inlet pipeline is connected with the gas supply unit through an on-off controllable leakage gas supply pipeline, and an on-off controllable detection branch is connected between every two adjacent flowmeters and between the detection gas inlet pipeline in parallel; and each inflation branch is connected with the detection air inlet pipeline through a serial leakage branch and is connected with the detection air outlet pipeline through an external leakage branch. According to the galvanic pile leakage detection system, the problem that the reading of the flowmeter fluctuates for a long time due to sudden flow change caused by opening and closing of the on-off valve in the measuring range switching process of the flow detection unit is solved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell detection technology, and in particular to a fuel cell stack leakage detection system. In addition, the present invention also relates to a fuel cell stack leakage detection method. Background Art

[0002] A fuel cell, also known as a fuel cell stack, is a device that converts chemical energy directly into electrical energy. It has the advantages of high efficiency, environmental protection, and low noise; but its airtightness is crucial to ensuring the safety and stability of the fuel cell.

[0003] The main purpose of fuel cell leak detection technology is to detect leaks in the fuel cell system, including hydrogen cavity leakage, coolant cavity leakage, air cavity leakage, cavity cross-leakage, etc.

[0004] The current fuel cell leakage detection equipment has a control method that performs the steps of cavity filling, gas stabilization, test start, result output, exhaust, etc. in sequence according to the test logic of the preset hydrogen cavity. The set time of each step is accumulated in sequence, which makes the entire test process too long, resulting in reduced test efficiency. At the same time, the existing detection method also has the following disadvantages:

[0005] 1. The flow rates measured by cavity external leakage and cross leakage are very different, and flow meters with different ranges are required to measure them separately to meet the measurement accuracy requirements; when external leakage and cross leakage are detected by flow meters with the same range, the measurement of cross leakage cannot cover the flow accuracy requirements of external leakage, resulting in low compatibility of the detection system;

[0006] Second, the manufacturing cost of high-precision mass flow meters is high, accounting for a large proportion of the total cost of leak detection equipment. If too many are equipped in the equipment, the cost will surge;

[0007] 3. Most high-precision mass flow meters are based on the laminar pressure difference measurement principle. During the switching process of flow meters with different ranges, the vibration caused by valve switching and the fluctuation caused by sudden flow rate changes will cause the flow meter readings to fluctuate. The greater the fluctuation, the longer it takes to stabilize, which will increase the test time and reduce the production test efficiency. Summary of the invention

[0008] In view of this, the present invention aims to propose a stack leakage detection system to improve the problem of long-term fluctuations in flow meter readings caused by sudden flow changes due to the opening and closing of an on-off valve during range switching of a flow detection unit.

[0009] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0010] A fuel cell stack leakage detection system comprises a gas supply unit, gas charging branches respectively connected to each chamber of a fuel cell stack core and the gas supply unit, and a flow detection unit;

[0011] A plurality of flow meters with gradually larger measuring ranges are connected in series between the detection air inlet pipeline and the detection air outlet pipeline of the flow detection unit; the detection air inlet pipeline is connected to the air supply unit via an on-off controllable external leakage air supply pipeline, and an on-off controllable detection branch is connected in parallel between two adjacent flow meters and the detection air inlet pipeline; an on-off valve is provided on each of the inflation branches, and each of the inflation branches is connected to the detection air inlet pipeline via an on-off controllable series leakage branch, and is connected to the detection air outlet pipeline via an on-off controllable external leakage branch.

[0012] Furthermore, each of the inflation branches is connected to the air supply unit via a main pipeline;

[0013] The air supply unit includes an air supply pipeline, and a plurality of pressure reducing valves arranged in series between the air supply pipeline and the main pipeline; along the air supply direction, the pressure reducing specifications of each pressure reducing valve are set to gradually decrease, and a pressure reducing branch with controllable on / off is provided between two adjacent pressure reducing valves and the main pipeline.

[0014] Furthermore, there are at least three flow meters arranged in sequence, and / or there are at least three pressure reducing valves arranged in sequence.

[0015] Furthermore, it also includes an inflation pressure detection device respectively arranged on each of the inflation branches, and each of the inflation pressure detection devices is used to respectively detect the pressure value in the corresponding chamber.

[0016] Furthermore, a bypass pipeline with controllable on / off is connected between the detection air inlet pipeline and the detection air outlet pipeline.

[0017] Furthermore, each of the external leakage branches is connected to the detection air outlet pipeline via an external leakage main pipeline, a leakage discharge port is provided at the end of the external leakage main pipeline, and on-off valves are provided on the external leakage main pipeline on both sides of the detection air outlet pipeline connection point; and / or, each of the string leakage branches is connected to the detection air inlet pipeline via a string leakage main pipeline, an exhaust port is provided at the end of the string leakage main pipeline, and on-off valves are provided on the string leakage main pipeline on both sides of the connection point of each of the string leakage branches.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The stack leakage detection system of the present invention connects a plurality of flow meters with gradually larger ranges in series in the flow detection unit in sequence, and controls the on-off of the detection branch in a timely manner, so as to introduce the corresponding flow meters into the flow measurement. During the switching and adjustment process of the entire flow range, since there is always airflow passing through each flow meter, and the increase or decrease of the flow is a gradual process, the change of the flow value monitored by each flow meter is a gradual and stable process. Compared with the traditional method of connecting a plurality of flow meters in parallel and measuring the flow separately, the flow detection unit of the present invention can greatly improve the problem of long-term fluctuation of the flow meter reading caused by the sudden change of the flow caused by the opening and closing of the on-off valve during the range switching of the flow detection unit.

[0020] In addition, through the setting of relevant pipelines and on-off valves such as each external leakage branch and its external leakage main pipeline, and the cross leakage branch and its cross leakage main pipeline, after completing the leakage detection, not only can the gas in the system be emptied into the atmosphere by opening the on-off valves on each cross leakage branch and the cross leakage main pipeline; but also, when switching between the two different leakage detection types of external leakage detection and cross leakage detection, the flow detection unit can be transferred from the air intake pipeline of the anode chamber to the exhaust pipeline of the cathode chamber only by reasonably controlling the on-off of the relevant pipelines; this plays an important role in the flexible use of the flow detection unit, reducing the number of flow meters configured, and improving the detection efficiency.

[0021] Another object of the present invention is to provide a stack leakage detection method, the leakage detection method comprising external leakage detection, the external leakage detection comprising an inflation step and a test step arranged in sequence;

[0022] The inflation step comprises:

[0023] Filling each chamber of the fuel cell with a gas of a first set pressure respectively, and monitoring the gas pressure value in the chamber filled with gas in real time;

[0024] Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and maintained for the first set time, it is determined that the inflation step is completed and the test step is performed;

[0025] The testing steps include:

[0026] Maintaining the inflation state of the inflation step and monitoring the flow value of the gas charged into the anode chamber of the fuel cell in real time;

[0027] Within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for a second set time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, the test is judged to be qualified.

[0028] Further, the leakage detection method includes a cross-leakage detection, and the cross-leakage detection includes an inflation step and a test step arranged in sequence;

[0029] The inflation step comprises:

[0030] Filling a gas of a second set pressure into the anode chamber of the fuel cell, and monitoring the gas pressure value in the chamber filled with gas in real time;

[0031] Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and maintained for the first set time, it is determined that the inflation step is completed and the test step is performed;

[0032] The testing steps include:

[0033] Maintaining the inflation state of the inflation step and monitoring the flow value of the gas discharged from the cathode chamber of the fuel cell in real time;

[0034] Within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for a second set time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, the test is judged to be qualified.

[0035] Furthermore, the set pressure range adopts the error range of the inflation pressure detection device that monitors the air pressure value; and / or, the set flow range adopts the error range of the flow detection unit that monitors the flow value; and / or, the first set pressure is 3 to 5 times the second set pressure.

[0036] Furthermore, in the test step, the same flow detection unit with an adjustable measurement range is used to monitor the flow value for the external leakage detection and the cross-leakage detection respectively.

[0037] The stack leakage detection method of the present invention overcomes the disadvantages of the prior art that the inflation step has a fixed inflation time, resulting in poor reliability of the inflation effect and a lot of time consumption, by setting more flexible and accurate judgment conditions for the inflation step. The inflation step is terminated in time after the pressure value in each chamber of the fuel cell has stabilized and the real test conditions have been met, which is not only conducive to improving the overall detection efficiency, but also ensures the accuracy and reliability of the detection. The test step adopts similar judgment conditions, and the actual leakage amount is confirmed only after the flow value is stable, which eliminates the situation where the flow value is not the real leakage flow due to factors such as chamber expansion or contraction, thereby improving the accuracy of leakage detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which constitute part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention. The directional terms such as front and back, up and down, etc. involved therein are only used to indicate relative positional relationships and do not constitute improper limitations on the present invention. In the accompanying drawings:

[0039] Figure 1 A schematic diagram of the system composition principle of the stack leakage detection system according to an embodiment of the present invention;

[0040] Figure 2 It is a schematic diagram of the principle of the flow detection unit according to an embodiment of the present invention;

[0041] Figure 3 It is a schematic diagram of the principle of the air supply unit according to an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of a control flow of external leakage detection in a stack leakage detection method according to an embodiment of the present invention;

[0043] Figure 5 A schematic diagram of the gas flow of the stack leakage detection system according to an embodiment of the present invention when performing external leakage detection;

[0044] Figure 6 A schematic diagram of a control flow of cross-leakage detection in a stack leakage detection method according to an embodiment of the present invention;

[0045] Figure 7 A schematic diagram of the gas flow of the stack leakage detection system according to an embodiment of the present invention when performing cross-leakage detection;

[0046] Figure 8 A schematic diagram of a control flow for determining the end of the charging step in the stack leakage detection method according to an embodiment of the present invention;

[0047] Fig. 9 It is a schematic diagram of the control flow for adjusting the measurement range of the flow detection unit in the fuel cell stack leakage detection method described in an embodiment of the present invention.

[0048] Description of reference numerals:

[0049] 1. Air supply pipeline; 10. Filter;

[0050] 20. Gas supply pressure detection device; 21. First pressure reducing branch; 22. Second pressure reducing branch; 23. Third pressure reducing branch; 201. First pressure reducing valve; 202. Second pressure reducing valve; 203. Third pressure reducing valve;

[0051] 301, first air supply valve; 302, second air supply valve; 303, third air supply valve; 304, first inflation branch valve; 305, second inflation branch valve; 306, third inflation branch valve; 307, fourth inflation branch valve; 308, external leakage main valve one; 309, first external leakage branch valve; 310, second external leakage branch valve; 311, third external leakage branch valve; 312, fourth external leakage branch valve; 313, first string leakage branch valve; 314, second string leakage branch valve; 315, third string leakage branch valve; 316, fourth string leakage branch valve; 317, drain valve; 318, string leakage main valve; 319, first range switching valve; 320, second range switching valve; 321, bypass valve; 322, external leakage main valve two; 323, string leakage drain valve;

[0052] 4. Main pipeline; 40. External leakage air supply pipeline; 41. First air filling branch; 42. Second air filling branch; 43. Third air filling branch; 44. Fourth air filling branch; 401. First pressure sensor; 402. Second pressure sensor; 403. Third pressure sensor; 404. Fourth pressure sensor;

[0053] 5. Flow detection unit; 50. Detection air inlet pipeline; 51. Medium-volume detection branch; 52. High-volume detection branch; 53. Detection air outlet pipeline; 54. Bypass pipeline; 501. First flow meter; 502. Second flow meter; 503. Third flow meter;

[0054] 6. External leakage main pipeline; 60. String leakage outlet; 61. First external leakage branch; 62. Second external leakage branch; 63. Third external leakage branch; 64. Fourth external leakage branch;

[0055] 7. String leakage main pipeline; 70. Drain port; 71. First string leakage branch; 72. Second string leakage branch; 73. Third string leakage branch; 74. Fourth string leakage branch;

[0056] 80. Stack shell; 81. Anode cavity; 82. Cathode cavity; 83. Cooling cavity. DETAILED DESCRIPTION

[0057] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0058] In the description of the present invention, it should be stated that if terms indicating directions or positional relationships such as "up, down, left, right, front, back, inside, outside" appear, they are based on the directions or positional relationships shown in the drawings and are only for the convenience of describing the present invention. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed or operate in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0059] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installed", "connected", "connection", and "connector" should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between the two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances. The limiting terms such as "first, second, A, B, C, D" that appear in the description of the present invention are only for distinguishing similar features of different positions, affiliations or uses, so as to achieve the purpose of avoiding ambiguity and confusion in the description, and cannot be understood as indicating or implying relative importance.

[0060] In addition, the chambers of the fuel cell mentioned in the embodiments of the present invention mainly include an anode chamber, a cathode chamber, and a cooling chamber, wherein the anode chamber is also called a hydrogen chamber, the cathode chamber is also called an air chamber, and the cooling chamber can also be called a water chamber. The external leakage mentioned refers to the situation where the cavity leaks to the outside of the core, and the external leakage detection is the detection of the leakage amount in this case; the cross-leakage refers to the situation where the gas leaks between the three cavities of the anode chamber, cathode chamber, and cooling chamber inside the core, and the cross-leakage detection is the detection of the leakage amount in this case. NCCM is the unit of gas flow, which is standard milliliters per minute.

[0061] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0062] Embodiment 1

[0063] This embodiment relates to a stack leakage detection system, which can improve the problem of long-term fluctuations in flow meter readings caused by sudden changes in flow rate due to the opening and closing of the on-off valve during the range switching of the flow detection unit 5. An exemplary system structure of the leakage detection system is as follows Figure 1 and Figure 2 shown.

[0064] In general, the stack leakage detection system includes a gas supply unit, a gas charging branch connected to each chamber of the fuel cell stack core and the gas supply unit, and a flow detection unit 5. Among them, a plurality of flow meters with gradually increasing ranges are arranged in series between the detection gas inlet pipeline 50 and the detection gas outlet pipeline 53 of the flow detection unit 5, and the detection gas inlet pipeline 50 is connected to the gas supply unit through an on-off controllable external leakage gas supply pipeline 40, and an on-off controllable detection branch is connected in parallel between the two adjacent flow meters and the detection gas inlet pipeline 50. At the same time, an on-off valve is provided on each gas charging branch, and each gas charging branch is connected to the detection gas inlet pipeline 50 through an on-off controllable series leakage branch, and is connected to the detection gas outlet pipeline 53 through an on-off controllable external leakage branch.

[0065] It should be pointed out that, based on the above-mentioned overall design concept, the technical solution of the present invention can adopt a variety of different specific implementation structures, forms or configuration sequences. For example, the specific number of flow meters in the above-mentioned flow detection unit 5 can be reasonably configured according to the change in the leakage amount of the fuel cell in different test types, and can be two, three or more units. The on-off controllable pipeline can be achieved by setting different types of on-off valves such as automatic control valves or manual valves on the pipeline. For the parts required for the implementation of the overall solution but not involved in the above-mentioned overall setting, reasonable and flexible designs can be made with reference to the mature setting means in the field, the actual situation during implementation, etc. The specific implementation scheme described below in this embodiment is only one of the better solutions that can be formed by the above-mentioned various combinations and their changes. In actual implementation, those skilled in the art can make flexible adjustments and improvements in combination with the actual situation. Obviously, the many solutions that can be formed by the above-mentioned various specific forms of combination and its changes, as well as the specific implementation scheme of this embodiment, are all within the scope of protection of the present invention.

[0066] Specifically, in this embodiment, if Figure 1 Combined with Figure 3 As shown, each gas-charging branch specifically includes a first gas-charging branch 41, a second gas-charging branch 42, a third gas-charging branch 43 and a fourth gas-charging branch 44, which are all connected to the gas supply unit through the main line 4; wherein, the first gas-charging branch 41 is connected to the anode cavity 81, the second gas-charging branch 42 is connected to the cathode cavity 82, the third gas-charging branch 43 is connected to the cooling cavity 83, and the fourth gas-charging branch 44 is connected to the stack shell 80, so as to supply gas to the corresponding chambers.

[0067] The air supply unit of this embodiment includes an air supply pipeline 1, and a plurality of pressure reducing valves arranged in series between the air supply pipeline 1 and the main pipeline 4, and the pressure reducing specifications of each pressure reducing valve are set to gradually decrease; a pressure reducing branch with controllable on / off is provided between the pipeline between two adjacent pressure reducing valves and the main pipeline 4.

[0068] Specifically, the air supply pipeline 1 of this embodiment is also provided with a filter 10; three pressure reducing valves are provided in the air supply unit, namely, a first pressure reducing valve 201, a second pressure reducing valve 202 and a third pressure reducing valve 203. Among them, the pipeline between the first pressure reducing valve 201 and the second pressure reducing valve 202 is connected to the main pipeline 4 through the first pressure reducing branch 21, and the first air supply valve 301 is provided on the first pressure reducing branch 21; the pipeline between the second pressure reducing valve 202 and the third pressure reducing valve 203 is connected to the main pipeline 4 through the second pressure reducing branch 22, and the second air supply valve 302 is provided on the second pressure reducing branch 22; the third pressure reducing valve 203 is connected to the main pipeline 4 through the third pressure reducing branch 23, and the third air supply valve 303 is provided on the third pressure reducing branch 23; the main pipeline 4 can be provided with a gas supply pressure detection device 20 to timely obtain the outlet pressure of the gas supply unit.

[0069] It can be seen that the air supply unit of this embodiment adopts a design concept similar to that of setting multiple flow meters in series in the flow detection unit 5. By timely controlling the on and off of the first air supply valve 301, the second air supply valve 302 and the third air supply valve 303, the on and off of each pressure reducing branch can be achieved, so that a smooth transition of the pressure regulation value change can be achieved between each pressure reducing valve, so as to improve the situation where the sudden change of air supply pressure and long-term pressure fluctuation caused by the air supply pressure adjustment of the air supply unit affect the detection process.

[0070] There are of course multiple options for the specific range selection of each of the above-mentioned flow meters and the specification selection of each pressure reducing valve. Preferably, in the flow detection unit 5 of this embodiment, there are at least three flow meters arranged in sequence; in this embodiment, they specifically include a first flow meter 501, a second flow meter 502 and a third flow meter 503, the range of the first flow meter 501 is 0.1-2.5NCCM, the range of the second flow meter 502 is 0.8-40NCCM, and the range of the third flow meter 503 is 20-1000NCCM. In the gas supply unit, along the gas supply direction, there are also at least three pressure reducing valves arranged in sequence; in this embodiment, they specifically include a first pressure reducing valve 201, a second pressure reducing valve 202 and a third pressure reducing valve 203; wherein, the pressure reducing specification of the first pressure reducing valve 201 is 180±30kPa, the pressure reducing specification of the second pressure reducing valve 202 is 50±10kPa, and the pressure reducing specification of the third pressure reducing valve 203 is 30±5kPa.

[0071] Based on the setting of the above-mentioned air supply unit, during external leakage detection, the leakage amount is usually small, and a larger air supply pressure can be used. At this time, closing the second air supply valve 302 and the third air supply valve 303, and only opening the first air supply valve 301 can provide a gas supply pressure of 180±30kPa; during cross-leakage detection, the leakage amount is usually large, and a smaller air supply pressure can be used. At this time, closing the first air supply valve 301 and the second air supply valve 302, and only opening the third air supply valve 303, or closing the first air supply valve 301 and the third air supply valve 303, and only opening the second air supply valve 302 can provide a gas supply pressure of 30±5kPa or 50±10kPa.

[0072] In addition, the leakage detection system of this embodiment also includes an inflation pressure detection device respectively arranged on each inflation branch, specifically including a first pressure sensor 401 arranged at the end of the first inflation branch 41, a second pressure sensor 402 arranged at the end of the second inflation branch 42, a third pressure sensor 403 arranged at the end of the third inflation branch 43, and a fourth pressure sensor 404 arranged at the end of the fourth inflation branch 44; each inflation pressure detection device can be used to detect the pressure value in the corresponding chamber respectively. By arranging an inflation pressure detection device on each inflation branch, the pressure conditions in each chamber such as the anode chamber 81, the cathode chamber 82, the cooling chamber 83 and the stack shell 80 in the fuel cell can be monitored in real time, so as to judge whether the inflation conditions in the leakage detection process of the fuel cell have met the leakage test requirements.

[0073] At the same time, a bypass line 54 with controllable on / off can be connected between the detection air inlet line 50 and the detection air outlet line 53; a bypass valve 321 is provided on the bypass line 54 to realize on / off control of the bypass line 54. By providing the bypass line 54 between the detection air inlet line 50 and the detection air outlet line 53 of the flow detection unit 5, during the period when flow monitoring is not required, such as the inflation step of the leak detection, the gas can be quickly bypassed by the flow detection unit 5 by opening the bypass line 54, which is not only conducive to quickly completing the inflation step, but also can reduce the burden of the flow detection unit 5 and increase the service life of the flow detection unit 5.

[0074] Based on the above-mentioned settings, in order to flexibly switch the flow direction of the gas between external leakage detection and cross leakage detection, in this embodiment, each external leakage branch is connected to the detection gas outlet pipeline 53 through the external leakage main pipeline 6, and a cross leakage discharge port 60 is provided at the end of the external leakage main pipeline 6. At the same time, an on-off valve is provided on the external leakage main pipeline 6 on both sides of the connection point of the detection gas outlet pipeline 53. Correspondingly, each cross leakage branch of this embodiment is connected to the detection gas inlet pipeline 50 through the cross leakage main pipeline 7, and an exhaust port 70 is provided at the end of the cross leakage main pipeline 7; at the same time, an on-off valve is provided on the cross leakage main pipeline 7 on both sides of the connection point of each cross leakage branch.

[0075] The first inflation branch 41 is provided with a first inflation branch valve 304 at one end connected to the main pipeline 4, and a first external leakage branch valve 309 is provided on the first inflation branch 41 downstream of the first inflation branch valve 304 and the first external leakage branch 61 between the main external leakage pipeline 6; the second inflation branch 42 is provided with a second inflation branch valve 305 at one end connected to the main pipeline 4, and a second external leakage branch valve 31 is provided on the second external leakage branch 62 between the second inflation branch 42 downstream of the second inflation branch valve 305 and the external leakage main pipeline 6. 0; a third air-charging branch valve 306 is provided at one end of the third air-charging branch 43 connected to the main pipeline 4, and a third external leakage branch valve 311 is provided on the third external leakage branch 63 between the third air-charging branch 43 and the external leakage main pipeline 6 downstream of the third air-charging branch valve 306; a fourth air-charging branch valve 307 is provided at one end of the fourth air-charging branch 44 connected to the main pipeline 4, and a fourth external leakage branch valve 312 is provided on the fourth external leakage branch 64 between the fourth air-charging branch 44 and the external leakage main pipeline 6 downstream of the fourth air-charging branch valve 307. At the same time, a leakage drain valve 323 is provided on the external leakage main pipeline 6 between the position of the external leakage main pipeline 6 connecting the detection air outlet pipeline 53 and the leakage drain port 60, and an external leakage main valve 2 322 is provided on the external leakage main pipeline 6 between the position of the external leakage main pipeline 6 connecting the detection air outlet pipeline 53 and each external leakage branch.

[0076] Similarly, a first string leakage branch valve 313 is provided on the first string leakage branch 71 between the first inflation branch 41 downstream of the above-mentioned first inflation branch valve 304 and the string leakage main pipeline 7; a second string leakage branch valve 314 is provided on the second string leakage branch 72 between the second inflation branch 42 downstream of the second inflation branch valve 305 and the string leakage main pipeline 7; a third string leakage branch valve 315 is provided on the third string leakage branch 73 between the third inflation branch 43 downstream of the third inflation branch valve 306 and the string leakage main pipeline 7; and a fourth string leakage branch valve 316 is provided on the fourth string leakage branch 74 between the fourth inflation branch 44 downstream of the fourth inflation branch valve 307 and the string leakage main pipeline 7. At the same time, a drain valve 317 is provided on the drain port 70 and the position on the drain port 7 connecting each drain branch. A main drain valve 318 is provided on the drain port 7 and the position on the drain port 7 connecting each drain branch.

[0077] By setting up relevant pipelines and on-off valves such as each external leakage branch and its external leakage main pipeline 6, and the cross leakage branch and its cross leakage main pipeline 7, after completing the leakage detection, not only can the gas in the system be discharged to the atmosphere by opening the on-off valves on each cross leakage branch and the cross leakage main pipeline 7; but also, when switching between the two different leakage detection types of external leakage detection and cross leakage detection, the flow detection unit 5 can be transferred from the air intake pipeline of the anode chamber 81 to the exhaust pipeline of the cathode chamber 82 only by reasonably controlling the on-off of the relevant pipelines; this plays an important role in the flexible use of the flow detection unit 5, reducing the number of flow meters configured, and improving the detection efficiency.

[0078] To summarize, the stack leakage detection system of the present embodiment connects a plurality of flow meters with gradually larger ranges in series in the flow detection unit 5 in sequence, and controls the on-off of the detection branch in a timely manner, so as to introduce the corresponding flow meters into the flow measurement. During the entire flow range switching and adjustment process, since there is always airflow passing through each flow meter, and the increase or decrease of the flow rate is a gradual process, the change of the flow value monitored by each flow meter is a gradual and stable process. Compared with the traditional method of connecting multiple flow meters in parallel and measuring the flow rate separately, the flow detection unit 5 of the present invention can greatly improve the problem of long-term fluctuation of the flow meter reading caused by the sudden change of flow rate due to the opening and closing of the on-off valve during the range switching of the flow detection unit 5.

[0079] Embodiment 2

[0080] This embodiment relates to a method for detecting leakage of a battery stack, and an exemplary control process thereof is as follows: Figure 4 and Figure 6 shown.

[0081] In general, the stack leakage detection method includes external leakage detection, which includes an inflation step and a testing step that are arranged in sequence.

[0082] Among them, the inflation steps of the leakage detection include:

[0083] Filling each chamber of the fuel cell with a gas of a first set pressure respectively, and monitoring the gas pressure value in the chamber filled with gas in real time;

[0084] Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and maintained for the first set time, it is determined that the inflation step is completed and the test step is performed.

[0085] The test steps for leakage detection include:

[0086] Maintaining the inflation state of the inflation step and monitoring the flow value of the gas charged into the anode chamber 81 of the fuel cell in real time;

[0087] Within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for the second set time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, the test is judged to be qualified.

[0088] In addition, the stack leakage detection method of the present invention also includes cross-talk leakage detection, which also includes a gas filling step and a test step that are arranged in sequence.

[0089] Among them, the inflation steps of the cross-talk detection include:

[0090] Filling the anode chamber 81 of the fuel cell with a gas of a second set pressure, and monitoring the gas pressure value in the chamber filled with the gas in real time;

[0091] Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and maintained for the first set time, the inflation step is determined to be completed and the test step is performed.

[0092] The test steps for cross-talk detection include:

[0093] Maintaining the inflation state of the inflation step and monitoring the flow value of the gas discharged from the cathode chamber 82 of the fuel cell in real time;

[0094] Within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for the second set time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, the test is judged to be qualified.

[0095] It should be pointed out that the above-mentioned external leakage detection and cross-leakage detection are carried out separately based on different detection purposes. Before the detection, it is first necessary to determine which chambers in the fuel cell are filled with gas according to the different detection types of external leakage detection and cross-leakage detection; then, while filling the determined chambers, the air pressure value in the chamber filled with gas is monitored in real time. Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and can be maintained for the first set time, it is determined that the inflation step is completed to carry out the subsequent test steps; otherwise, the detection is determined to be unqualified and the entire detection process is terminated.

[0096] Regarding the determination of the chambers that need to be inflated: for external leakage detection, the anode chamber 81, cathode chamber 82 and cooling chamber 83 of the fuel cell need to be respectively filled with gas of the first set pressure; for cross-leakage detection, only the anode chamber 81 is filled with gas of the second set pressure. It should be pointed out. The values ​​of the first set pressure and the second set pressure described here can be the same or different, and should be reasonably selected and set according to the gas supply pressure required for different detection types. It is preferred to set the first set pressure to 3 to 5 times the second set pressure.

[0097] In this embodiment, based on the configuration of the air supply unit in the first embodiment, the second air supply valve 302 and the third air supply valve 303 are closed during external leakage detection, and only the first air supply valve 301 is opened, and the pressure is adjusted by the first pressure reducing valve 201 to provide a supply pressure of 180±30kPa; then the first set pressure is set within the range of 180±30kPa. During cross-leakage detection, the first air supply valve 301 and the third air supply valve 303 are closed, and only the second air supply valve 302 is opened, and the pressure adjustment of the second pressure reducing valve 202 provides a supply pressure of 50±10kPa; then the second set pressure is set within the range of 50±10kPa.

[0098] In the test step, the inflation state in the inflation step still needs to be maintained; at the same time, for external leakage detection, the flow value of the gas filled into the anode chamber 81 is monitored in real time; for cross-leakage detection, the flow value of the gas discharged from the cathode chamber 82 is monitored in real time. The logic for judging whether the test is qualified is: within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for the second set time, and at the same time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, then the test is judged to be qualified; otherwise, the test is judged to be unqualified.

[0099] In order to facilitate a better understanding of the entire test process, the following describes two different types of detection processes, external leakage detection and cross-leakage detection, respectively, taking the leakage detection system provided in Example 1 as an example.

[0100] like Figure 4 Combined with Figure 5 As shown, in the leakage detection process of detecting whether there is leakage in the anode chamber 81 and how much leakage there is, the gas flow direction in the leakage detection system is as follows: Figure 5 As shown, the solid arrows in the figure show the gas flow direction in the testing step, and the dotted arrows show the gas flow direction in the inflation step.

[0101] First, in the gas charging step, the first gas supply valve 301, the first gas charging branch valve 304 to the third gas charging branch valve 306, the external leakage main valve 1 308 to the third external leakage branch valve 311, the bypass valve 321 to the external leakage main valve 2 322 are opened; the first series leakage branch valve 313 to the drain valve 317, and other irrelevant on-off valves are closed; so as to respectively supply gas to the anode chamber 81, the cathode chamber 82 and the cooling chamber 83. After it is determined that the gas charging step is completed, the test step is entered.

[0102] When entering the test step, close the first inflation branch valve 304, the second external leakage branch valve 310, the third external leakage branch valve 311 and the bypass valve 321; the opening and closing conditions of the first range switching valve 319 and the second range switching valve 320 in the flow detection unit 5 can be controlled according to the range adjustment needs of the flow detection unit 5.

[0103] It should be noted that during the leakage detection process, Figure 5 In the state of inflating and pressurizing the cathode chamber 82 and the cooling chamber 83 as shown by the middle dotted arrow, if the conditions for ending the inflation step can be met (i.e., the monitored air pressure values ​​are all stable within the set pressure range and can be maintained for the first set time), it can be said that there is no leakage between the anode chamber 81, the cathode chamber 82, the cooling chamber 83 and other chambers at this time, and therefore the flow value monitored in the test step is the external leakage flow of the anode chamber 81.

[0104] like Figure 6 Combined with Figure 7 As shown, in the process of detecting whether there is leakage between the anode chamber 81 and the cathode chamber 82 and how much leakage there is, the gas flow direction in the leakage detection system is as follows: Figure 7 As shown, the solid arrow in the figure shows the gas flow direction of filling the anode chamber 81, and the dotted arrow shows the gas flow direction of leakage from the anode chamber 81 to the cathode chamber 82 and discharge from the cathode chamber 82 to the external atmosphere during the test step.

[0105] First, in the gas charging step, the second gas supply valve 302, the first gas charging branch valve 304, the leakage main valve 318, the bypass valve 321, the leakage drain valve 323 are opened, and the first leakage branch valve 313, the third leakage branch valve 315-the drain valve 317, and other irrelevant on-off valves are closed; thereby supplying gas into the anode chamber 81 and ensuring that the exhaust passage from the cathode chamber 82 to the outside is unobstructed, and at the same time flowing through the flow detection unit 5. After it is determined that the gas charging step is completed, the test step is entered.

[0106] When entering the test step, the bypass valve 321 is closed; the opening and closing of the first range switching valve 319 and the second range switching valve 320 in the flow detection unit 5 are controlled according to the range adjustment requirements of the flow detection unit 5. By placing the flow detection unit 5 on the external discharge channel of the cathode chamber 82, the interference flow generated by the leakage of the anode chamber 81 and the cross-leakage between the anode chamber 81 and the cooling chamber 83 can be stripped, so that the cross-leakage flow from the anode chamber 81 to the cathode chamber 82 can be accurately measured in the test step, meeting the needs of rapid verification of the sealing interface between the hydrogen production chamber and the air chamber.

[0107] For the specific logic and control steps for determining the end of the inflation step, please refer to Figure 8 shown.

[0108] Specifically, according to the ideal gas equation of Boyle-Malior law (Equation 1):

[0109] PV=nRT(1)

[0110] Among them, P is the gas pressure, V is the effective volume of the container, n is the molar mass, R is the ideal gas constant, and T is the temperature.

[0111] When the test process environment is a constant temperature environment and the temperature effect is ignored, equation 1 can be simplified to equation 2:

[0112] P=nC(2)

[0113] Where C is a constant, it can be seen that the gas pressure is proportional to the mass of the gas in the container.

[0114] During the inflation step, the gas state is as follows:

[0115] Q IN =Δn×22.4+Q OUT …(3)

[0116] Where Q IN is the inflation flow rate, Q OUT is the leakage flow rate of the measured chamber, Δn is the molar mass of the gas added inside the measured chamber per unit time;

[0117] When the inflation is complete, Q IN With Q OUT equal, at this time Δn is 0, that is, the change value ΔP of the internal pressure of the container per unit time is 0.

[0118] According to the above principles, the pressure value is analyzed and calculated in the inflation step as follows:

[0119]

[0120] ΔP=P t -P t-1 …………(5)

[0121] In this way, the pressure change value ΔP is calculated according to the monitored air pressure value; at this time, it is more reasonable to set the pressure range using the error range of the inflation pressure detection device that monitors the air pressure value. When the inflation pressure detection device uses a pressure sensor with an absolute error value of 0.4kPa, the set pressure range can be set to 0.4kPa; at the same time, the first set time can be set to 5s (seconds) to eliminate the instantaneous fluctuation of the measured value caused by factors such as signal interference. The inflation time limit can be reasonably set according to the use of the system, for example, set to 60s.

[0122] Summarizing the above situations, such as Figure 8As shown, within the inflation time limit of 60s, when ΔP≤0.4kPa and can be maintained for 5s, it can be determined that the inflation step is completed; if within the inflation time limit of 60s, ΔP has not been able to stabilize below 0.4kPa and continue for 5s, it is determined that there is a serious leakage in the chamber of the fuel cell, which obviously does not meet the detection requirements and should be determined as unqualified.

[0123] In the test step, the specific logic and control idea for determining whether the flow value has tended to be stable are similar to the judgment logic for the completion of inflation in the inflation step, and can be implemented with reference to the contents of the above inflation step.

[0124] The difference is that due to the large volume of the chamber being tested, the high test pressure, and the elasticity of the interior of the fuel cell chamber, the flow value measured by the flow meter is not the actual leakage flow in the initial stage of the start-up test. The state of gas flow at this time is shown in the following formula 6:

[0125] Q ac =Q hc +Q pz +Q out ……………………………………………………(6)

[0126] Where: Q hc The slow inflation flow rate of the chamber (the inflation process does not reach absolute inflation balance due to the accuracy of the pressure sensor); Q pz The gas flow rate to be supplemented (exhausted) during the expansion (contraction) process of the measured chamber, Q out is the actual leakage flow.

[0127] In the prior art, since a fixed time is waited for buffering to complete and then the measured flow value is read, there is a high probability that an unreal leakage amount (Q hc and Q pz ) and lead to misjudgment.

[0128] In the present invention, the flow rate Q of the gas monitored and read per unit time is used to calculate the change rate Δa of the flow value Q per unit time in real time, and the change rate Δa of the measured flow is judged, which can effectively eliminate the non-real leakage (Q hc and Q pz ), the specific implementation method is shown in the following formula 7:

[0129] Δa=ΔQ / Q t-1 =(Q t -Q t-1 ) / Q t-1 …………(7)

[0130] Where ΔQ is the change in the sampling flow value per unit time, Q tis the flow value sampled at the current moment, Q t-1 is the flow value sampled at the last moment, and Δa is the flow change rate.

[0131] At this time, it is more reasonable to set the flow range according to the error range of the flow detection unit 5 that monitors the flow value, that is, the error value of the mass flow meter currently used as the main measurement in the flow detection unit 5 can be used as the setting flow range. At the same time, the second setting time can also be set to 5s (seconds) to eliminate the situation of instantaneous fluctuations in the measured value caused by factors such as signal interference. The test time limit can be reasonably set according to the use of the system, for example, set to 60s, 100s, etc.

[0132] In this way, within the set test time limit, when ΔQ ≤ the error value of the flow meter (that is, Δa ≤ the accuracy value of the flow meter) and can be maintained for 5s, it can be judged that the current leakage state has stabilized and the non-real leakage amount is close to 0. The flow value measured at this moment is the real leakage flow Q out This method can reduce the misjudgment of the test and shorten the waiting time of the test steps, avoiding the decline in production test efficiency caused by long waiting time.

[0133] The flow value obtained at this moment can be used as the leakage flow Q out As a test result output, if the leakage flow Q out If the leakage is below the set value determined according to the relevant specifications, and the pressure value detected by the current inflation pressure detection device is still stable within the set pressure range (that is, there is no serious leakage in the fuel cell chamber), the test is considered qualified. out If the leakage exceeds the set requirement, or the flow value monitored within the set test time limit cannot be stabilized (this indicates that there is abnormal leakage or change in the fuel cell chamber), it means that the sealing performance of the fuel cell chamber cannot meet the requirements of relevant specifications and the test is judged to be unqualified.

[0134] From the above, it can be seen that the stack leakage detection method of the present embodiment overcomes the disadvantages of the prior art that the inflation step has a fixed inflation time, resulting in poor reliability of the inflation effect and long time consumption, by setting more flexible and accurate judgment conditions for the inflation step; the inflation step is terminated in time after the pressure value in each chamber of the fuel cell has stabilized and the real test conditions have been met, which is not only conducive to improving the overall detection efficiency, but also ensures the accuracy and reliability of the detection; the test step adopts similar judgment conditions, and the actual leakage amount is confirmed only after the flow value is stable, which eliminates the situation where the flow value is not the actual leakage flow due to factors such as chamber expansion or contraction, thereby improving the accuracy of leakage detection.

[0135] In addition, in the test steps, based on the leakage detection system and its flow detection unit 5 provided in Example 1, it can be seen that whether in the external leakage test or the cross leakage test, the system adopts the same flow detection unit 5 with an adjustable measurement range. Through the on-off control of the relevant pipelines, the flow detection unit 5 can monitor the flow value for external leakage detection and cross leakage detection respectively; and, in view of the fact that the flow values ​​monitored during external leakage detection and cross leakage detection usually have an order of magnitude difference, therefore, the present invention configures the flow detection unit 5 in a form with an adjustable measurement range.

[0136] Specifically, if Figure 1 , Figure 2 Combined with Fig. 9 As shown, the measuring range of the flow detection unit 5 of this embodiment can be adjusted in the following manner:

[0137] A plurality of flow meters with gradually larger ranges are arranged in series between the detection air inlet pipeline 50 and the detection air outlet pipeline 53 of the flow detection unit 5, specifically a first flow meter 501 (with a range of 0.1-2.5 NCCM), a second flow meter 502 (with a range of 0.8-40 NCCM) and a third flow meter 503 (with a range of 20-1000 NCCM); the pipeline between the first flow meter 501 and the second flow meter 502 is connected to the detection air inlet pipeline 50 through a medium-volume detection branch 51, and a first range switching valve 319 is provided on the medium-volume detection branch 51; the pipeline between the second flow meter 502 and the third flow meter 503 is connected to the detection air inlet pipeline 50 through a high-volume detection branch 52, and a second range switching valve 320 is provided on the high-volume detection branch 52.

[0138] Through the above-mentioned process pipeline design, the two tests of chamber leakage and chamber cross leakage can reuse a set of measurement circuits, and the range of the entire flow detection unit 5 can be switched and adjusted between 2.5NCCM, 40NCCM, and 1000NCCM. By controlling the opening and closing of the first range switching valve 319 and the second range switching valve 320, different ranges can be switched in real time according to the measured flow value, and each test can cover the test range of 0.025-1000NCCM; at the same time, low-disturbance switching of different ranges can be achieved through the range switching algorithm, thereby shortening the time of flow meter reading fluctuations caused by the opening and closing of the on-off valve, so as to improve production test efficiency.

[0139] In practical application, the opening and closing control of the first range switching valve 319 and the second range switching valve 320 can refer to Fig. 9 The flow ranges corresponding to different opening and closing states and their combinations are shown in the following table:

[0140] V19 V20 Flow range close close 0.1-2.0NCCM open close 2-36NCCM open Open 36-1000NCCM

[0141] The switching algorithm of each flow meter is as follows; among them, Formula 8 is the mean filtering of each flow meter, and Formula 9 is the real-time flow value read after adaptive range (i.e., automatic adjustment and switching of flow range):

[0142]

[0143] In formula 8, Q is the flow value after filtering; q i is the real-time sampling value of the flow meter; f is the sampling frequency.

[0144]

[0145] In formula 9, Q min Q is the flow sampling value of the flow meter with a range of 2.5NCCM; mid Q is the flow sampling value of the flow meter with a range of 40NCCM; max It is the flow sampling value of the flow meter with a range of 1000NCCM. ac The current flow detection unit 5 actually monitors and obtains a flow value, which is a flow sampling value of a flow meter with a selected range among the three flow meters.

[0146] It can be seen that through the design of the process pipeline, when measuring chamber outleakage and chamber cross-leakage, the chambers under test can be connected to the gas measurement circuit, which not only improves the measurement coverage but also saves the number of flow meters configured. Only three flow meters are needed to complete various leakage detections required for fuel cells with high accuracy, saving the overall manufacturing cost of the leakage detection system.

[0147] In summary, the leakage detection system of the present invention realizes the detection of various leakage tests during the production process of the fuel cell stack core, and compared with the existing fuel cell leakage detection device, it can save more than 10% of the manufacturing cost and about 20% of the maintenance cost. Moreover, based on the stack leakage detection method of this embodiment, the leakage detection system of the present invention is used to perform the leakage test of the fuel cell, which can realize the rapid detection of fuel cell stack core leakage and improve the production detection efficiency; at the same time, it is conducive to improving the accuracy of the test results and reducing the situation where the product function is affected by misjudgment during the test.

[0148] The above description is only a preferred embodiment of the present invention. The detailed explanation of the configuration, the examples of the specific structural setting forms, or the description of the assembly connection mode, etc., are all for the purpose of sufficient disclosure so that those skilled in the art can better implement the present invention, but are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A stack leakage detection system, characterized in that: It comprises an air supply unit, an air filling branch respectively connected to each chamber of the fuel cell stack and the air supply unit, and a flow detection unit (5); A plurality of flow meters with gradually increasing measuring ranges are connected in series between the detection air inlet pipeline (50) and the detection air outlet pipeline (53) of the flow detection unit (5); the detection air inlet pipeline (50) is connected to the air supply unit via an on-off controllable external leakage air supply pipeline (40), and an on-off controllable detection branch is connected in parallel between two adjacent flow meters and the detection air inlet pipeline (50); Each of the inflation branches is provided with an on-off valve, and each of the inflation branches is connected to the detection air inlet pipeline (50) via an on-off controllable leakage branch, and is connected to the detection air outlet pipeline (53) via an on-off controllable leakage branch.

2. The stack leakage detection system according to claim 1, characterized in that: Each of the inflation branches is connected to the air supply unit via a main pipeline (4); The gas supply unit comprises a gas supply pipeline (1), and a plurality of pressure reducing valves arranged in series between the gas supply pipeline (1) and the main pipeline (4); Along the gas supply direction, the pressure reducing specifications of the pressure reducing valves are set to be gradually smaller, and a pressure reducing branch with controllable on / off is provided between two adjacent pressure reducing valves and the main pipeline (4).

3. The stack leakage detection system according to claim 2, characterized in that: There are at least three flow meters arranged in sequence, and / or there are at least three pressure reducing valves arranged in sequence.

4. The stack leakage detection system according to claim 1, characterized in that: It also includes an inflation pressure detection device respectively arranged on each of the inflation branches, and each of the inflation pressure detection devices is used to respectively detect the pressure value in the corresponding chamber.

5. The stack leakage detection system according to claim 1, characterized in that: A bypass pipeline (54) whose on / off controllable nature is connected between the detection air inlet pipeline (50) and the detection air outlet pipeline (53).

6. The stack leakage detection system according to any one of claims 1 to 5, characterized in that: Each of the external leakage branches is connected to the detection air outlet pipeline (53) via the external leakage main pipeline (6), a leakage discharge port (60) is provided at the end of the external leakage main pipeline (6), and on-off valves are provided on the external leakage main pipeline (6) on both sides of the connection point of the detection air outlet pipeline (53); And / or, each of the string leakage branches is connected to the detection air inlet pipeline (50) via a string leakage main pipeline (7), an exhaust port (70) is provided at the end of the string leakage main pipeline (7), and on-off valves are provided on the string leakage main pipeline (7) on both sides of the connection point of each of the string leakage branches.

7. A method for detecting leakage of a battery stack, characterized in that: The leakage detection method includes external leakage detection, and the external leakage detection includes an inflation step and a testing step arranged in sequence; The inflation step comprises: Filling each chamber of the fuel cell with a gas of a first set pressure respectively, and monitoring the gas pressure value in the chamber filled with gas in real time; Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and maintained for the first set time, it is determined that the inflation step is completed and the test step is performed; The testing steps include: Maintaining the inflation state of the inflation step and monitoring the flow value of the gas injected into the anode chamber (81) of the fuel cell in real time; Within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for a second set time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, the test is judged to be qualified.

8. The stack leakage detection method according to claim 7, characterized in that: The leakage detection method includes a cross-leakage detection, and the cross-leakage detection includes an inflation step and a test step arranged in sequence; The inflation step comprises: Filling a gas of a second set pressure into the anode chamber (81) of the fuel cell, and monitoring the gas pressure value in the chamber filled with gas in real time; Within the set inflation time limit, when the monitored air pressure values ​​are all stable within the set pressure range and maintained for the first set time, it is determined that the inflation step is completed and the test step is performed; The testing steps include: Maintaining the inflation state of the inflation step and monitoring the flow value of the gas discharged from the cathode chamber (82) of the fuel cell in real time; Within the set test time limit, when the monitored flow value is stable within the set flow range and can be maintained for a second set time, the flow value is below the set leakage amount and the air pressure value is still stable within the set pressure range, the test is judged to be qualified.

9. The leakage detection method according to claim 8, characterized in that: The set pressure range adopts the error range of the inflation pressure detection device that monitors the air pressure value; And / or, the set flow rate range adopts the error range of the flow rate detection unit (5) that monitors the flow rate value; And / or, the first set pressure is 3 to 5 times the second set pressure.

10. The leakage detection method according to claim 8, characterized in that: In the test step, the same flow detection unit (5) with an adjustable measurement range is used to monitor the flow value for the external leakage detection and the cross-leakage detection respectively.

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