Gas tightness detection device for fuel cell stack

Abstract

The invention relates to the technical field of air tightness detection, and discloses a fuel cell stack air tightness detection device, which comprises a fuel cell stack main body, an air inlet pipe is installed on the outer wall of the fuel cell stack main body, and the outer wall of the air inlet pipe is sleeved with an air collection airbag. A driving gear is driven by an air pump to rotate through a rotating rod, a gear ring can be driven to rotate on the inner wall of a shell, a plurality of driving gears start to rotate, racks can move in the directions of the driving gears under the rotation of the driving gears, the vertexes of six moving plates can make contact with one another, and the moving plates can move in the directions of the driving gears. Therefore, the outside can be separated from the inner wall of the air inlet pipe, external air can be effectively prevented from continuously entering the inner wall of the fuel cell stack main body, gas waste can be effectively prevented, the safety and reliability of a fuel cell are ensured, gas leakage can be effectively reduced by quickly stopping gas charging, and the safety of the fuel cell stack is improved. Therefore, the risk of fire disasters or explosions is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of airtightness detection, and particularly to an airtightness detection device for a fuel cell stack. Background Art

[0002] The airtightness detection device for a fuel cell stack is an important device to ensure the safe operation of the fuel cell system, and its design and function are directly related to the safe use of fuels such as hydrogen.

[0003] Gases in the battery stack, such as hydrogen, are flammable and explosive. Their leakage may lead to serious safety accidents such as fires or explosions. However, the existing airtightness detection devices for fuel cell stacks cannot stop inflating in time when gas leakage is detected in the battery stack, thus easily posing a risk of fire or explosion; At the same time, the external leakage of hydrogen will directly lead to a decrease in the efficiency of the fuel cell system and a reduction in the utilization rate of hydrogen. The coolant may evaporate at high temperatures, and the vapor diffusion may cause abnormal pressure inside the stack. Oxygen is another important reaction gas in the fuel cell stack. Although it is not flammable itself, its leakage will exacerbate the risk of hydrogen combustion or explosion; At the same time, gas leakage easily causes imbalance of the internal pressure of the battery stack, further damaging the equipment and affecting its service life. And gas leakage easily causes equipment damage, increasing the costs of maintenance and replacement of components. Therefore, it needs to be improved. Summary of the Invention

[0004] The present invention provides an airtightness detection device for a fuel cell stack, which solves the problems raised in the above background art.

[0005] The present invention provides the following technical solution: an airtightness detection device for a fuel cell stack, including a fuel cell stack main body. An intake pipe is installed on the outer wall of the fuel cell stack main body. A gas collection airbag is sleeved on the outer wall of the intake pipe. Intake grooves and outlet grooves are opened at both ends of the fuel cell stack main body. An airtightness detection component is arranged at the top of the intake pipe. A placement groove is opened on the inner wall of the fuel cell stack main body. A gas leakage marking component is arranged on the inner wall of the placement groove. One end of the gas collection airbag close to the intake pipe is fixedly assembled with an electrode chip one. A limit block is fixedly installed at the top of the intake pipe. An electrode chip two is fixedly installed at one end of the limit block close to the gas collection airbag; The airtightness detection component includes an air pump. One end of an air delivery pipe is installed at the top of the air pump, and the other end of the air delivery pipe is fixedly assembled with a communicating pipe. The output end of the air pump is fixedly assembled with an air outlet pipe. A fan is fixedly installed at the bottom of the air outlet pipe. A rotating shaft is fixedly installed at the bottom of the fan. A bevel gear one is fixedly assembled at the bottom of the rotating shaft. A bevel gear two is meshed with the outer wall of the bevel gear one. A fixing plate is installed on the outer wall of the bevel gear two.

[0006] As a preferred technical solution of the present invention: the electrode chip one and the electrode chip two have the same shape, and the virtual center lines of the electrode chip one and the electrode chip two coincide. When the electrode chip one contacts the electrode chip two, an electric current is generated, and this electric current is electrically connected to the air pump through a controller. The air collecting airbag is annularly arranged between the air inlet pipe and the fuel cell stack main body.

[0007] As a preferred technical solution of the present invention: the central axis of the bevel gear two is rotatably sleeved on the inner wall of the fixing plate. The top of the fixing plate is fixedly installed on the inner wall top of the air inlet pipe. The rotating shaft and the bevel gear one are perpendicularly arranged on the inner wall of the air inlet pipe, and the bevel gear one is rotatably sleeved on the inner wall of the air inlet pipe.

[0008] As a preferred technical solution of the present invention: a rotating rod is fixedly sleeved at the center of the fixing plate. A driving gear is fixedly assembled at one end of the rotating rod away from the fixing plate. The outer wall of the driving gear is respectively meshed with a toothed ring and a rack. The outer wall of the toothed ring is rotatably sleeved with a housing. The inner wall of the toothed ring is meshed with a driving gear. The rack is installed with a moving plate through a mounting bolt, and a sealing ring is fixedly assembled on the outer edge of the moving plate.

[0009] As a preferred technical solution of the present invention: the outer edge of the housing is fixedly installed on the inner wall of the air inlet pipe. The shape of the housing is a hollow ring. The driving gear and the driving gear are both rotatably connected to the inner wall of the housing. The diameter of the circle formed when the tips of the six moving plates contact each other is adapted to the diameter of the air inlet pipe.

[0010] As a preferred technical solution of the present invention: the number of the driving gears is five, and the five driving gears and one driving gear are evenly distributed on the inner wall of the toothed ring. The thickness of the toothed ring plus the thickness of the rack is equal to the thickness of the driving gear. The driving gear and the driving gear have the same shape. The number of the racks and the moving plates is six, and the six racks and the moving plates are evenly distributed on the outer wall of the toothed ring.

[0011] As a preferred technical solution of the present invention: the gas leakage marking assembly includes a ventilation disc. A ventilation pipe is fixedly assembled on the outer wall of the ventilation disc. Sealing plates are installed at both ends of the ventilation disc. Display lamps are installed on the outer walls of the sealing plates. Air outlet holes are opened on the outer wall of the ventilation pipe close to the ventilation disc. A gas collecting cylinder is embedded in the inner wall of the ventilation disc. A partition plate is fixedly assembled on the inner wall of the ventilation disc. A gas detector is arranged on the inner wall of the ventilation disc. An anti-backflow layer is installed at the bottom of the ventilation pipe. One end of the connecting pipe away from the air delivery pipe is located on the inner wall of the partition plate.

[0012] As a preferred technical solution of the present invention: there are four groups of the gas detectors, and the four groups of gas detectors are all in contact with the leaked gas through the air outlet holes. An LED chip is arranged in the inner cavity of the gas detector, and the LED chip is electrically connected to the sealing plate through a control circuit. The cross section of the partition plate is in a "cross" shape.

[0013] As a preferred technical solution of the present invention: the cross section of the anti-backflow layer is in an arc shape, and the concave part of the arc is located on the inner wall of the air collecting cylinder. There are four vent pipes, and both ends of the four vent pipes are in contact with the air inlet groove, the air outlet groove and the air vent disc respectively.

[0014] The present invention has the following beneficial effects: 1. For the fuel cell stack airtightness detection device, the driving gear rotates through the rotating rod driven by the air pump, which can drive the toothed ring to rotate on the inner wall of the outer shell, so that a plurality of driving gears start to rotate, and the rack can move along the direction of the driving gear under the rotation of the driving gear, so that the vertices of the six moving plates can be in contact, so that it can divide the outside from the inner wall of the air inlet pipe, effectively prevent the outside air from continuing to enter the inner wall of the fuel cell stack main body, and can effectively prevent the waste of gas, ensure the safety and reliability of the fuel cell. Quickly stopping inflation can effectively reduce the amount of gas leakage, thereby reducing the risk of fire or explosion; At the same time, stopping inflation in time can reduce the damage of leakage to the equipment, thereby saving the subsequent maintenance cost, and quickly stopping inflation can reduce the diffusion of harmful gases in the air, avoiding the inhalation of toxic or flammable gases by the staff, ensuring the safety of the working environment and protecting the equipment safety. And the device recycles the leaked gas, which can further improve the resource utilization rate.

[0015] 2. For the fuel cell stack airtightness detection device, the gas on the inner wall of the vent pipe is discharged from the air outlet hole to the inner wall of the air vent disc, so that the corresponding gas can be in contact with the gas detector, so that the display lamp changes color. Furthermore, the device can judge which vent pipe has a leakage situation by the color of the lit sealing plate while detecting the overall airtightness of the fuel cell stack main body, so that the device can timely discover and repair potential leakage points, ensure the airtightness of hydrogen in the stack, thereby reducing the safety risk, optimizing the performance of the fuel cell and reducing resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a three-dimensional structure schematic diagram of the present invention; Figure 2 is a schematic diagram of the structure on the other side of the present invention; Figure 3 is a sectional structure schematic diagram of the present invention; Figure 4 Schematic diagram of the internal structure of the present invention; Figure 5 Schematic diagram of the partial sectional structure of the present invention; Figure 6 Schematic diagram of the structure of the gas detector of the present invention; Figure 7 Schematic diagram of the structure of the intake pipe of the present invention; Figure 8 For the present invention Figure 7 Enlarged structure diagram at position A in; Figure 9 Schematic diagram of the structure of the airtightness detection component of the present invention; Figure 10 For the present invention Figure 9 Enlarged structure diagram at position B in; Figure 11 Schematic diagram of the sealed state of the present invention; Figure 12 Schematic diagram of the intake state of the present invention.

[0017] In the figure: 1. Main body of fuel cell stack; 2. Intake pipe; 3. Gas collecting airbag; 4. Intake groove; 5. Exhaust groove; 6. Airtightness detection component; 7. Placing groove; 8. Gas leakage marking component; 9. Electrode chip one; 10. Limit block; 11. Electrode chip two; 61. Air pump; 62. Air delivery pipe; 63. Connecting pipe; 64. Exhaust pipe; 65. Fan; 66. Rotating shaft; 67. Bevel gear one; 68. Bevel gear two; 69. Fixed plate; 610. Rotating rod; 611. Driving gear; 612. Tooth ring; 613. Outer shell; 614. Driving gear; 615. Rack; 616. Mounting bolt; 617. Moving plate; 618. Sealing ring; 81. Ventilation disc; 82. Ventilation pipe; 83. Sealing plate; 84. Display lamp; 85. Air outlet hole; 86. Air collecting cylinder; 87. Partition board; 88. Gas detector; 89. Anti-backflow layer. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Please refer to Figure 1 - Figure 12, a fuel cell stack airtightness detection device, including a fuel cell stack main body 1. An intake pipe 2 is installed on the outer wall of the fuel cell stack main body 1. A gas collection airbag 3 is sleeved on the outer wall of the intake pipe 2. Intake slots 4 and outlet slots are provided at both ends of the fuel cell stack main body 1. A gas tightness detection component 6 is provided at the top of the intake pipe 2. A placement slot 7 is provided on the inner wall of the fuel cell stack main body 1. A gas leakage marking component 8 is provided on the inner wall of the placement slot 7. One end of the gas collection airbag 3 close to the intake pipe 2 is fixedly assembled with an electrode chip one 9. A limiting block 10 is fixedly installed at the top of the intake pipe 2. An electrode chip two 11 is fixedly installed at one end of the limiting block 10 close to the gas collection airbag 3; The gas tightness detection component 6 includes an air pump 61. One end of an air delivery pipe 62 is installed at the top of the air pump 61, and the other end of the air delivery pipe 62 is fixedly assembled with a connecting pipe 63. The output end of the air pump 61 is fixedly assembled with an air outlet pipe 64. A fan 65 is fixedly installed at the bottom of the air outlet pipe 64. A rotating shaft 66 is fixedly installed at the bottom of the fan 65. A bevel gear one 67 is fixedly assembled at the bottom of the rotating shaft 66. A bevel gear two 68 is meshed with the outer wall of the bevel gear one 67. A fixing plate 69 is installed on the outer wall of the bevel gear two 68.

[0020] In the above structure, through the opening of the intake slot 4 and the outlet slot 5, when the opening and closing of the intake slot 4 and the outlet slot 5 are controlled, the three-chamber pressure holding detection of the device can be carried out. Before the airtightness detection of the device, the preliminary airtightness detection work can be carried out by controlling the opening and closing of the intake slot 4 and the outlet slot 5, so as to ensure that the subsequent airtightness detection of the device can be more accurate.

[0021] In a preferred embodiment: The electrode chip one 9 and the electrode chip two 11 have the same shape, and the virtual center lines of the electrode chip one 9 and the electrode chip two 11 coincide. When the electrode chip one 9 contacts the electrode chip two 11, a current will be generated, and this current is electrically connected to the air pump 61 through the controller. The gas collection airbag 3 is annularly arranged between the intake pipe 2 and the fuel cell stack main body 1.

[0022] In the above structure, when the gas collection airbag 3 collects enough gas, the gas collection airbag 3 will expand, so that the electrode chip one 9 on the outer wall of the gas collection airbag 3 contacts the electrode chip two 11. At this time, a current will pass through. According to the characteristic that this current is electrically connected to the air pump 61 through the controller, it can be known that when the electrode chip one 9 contacts the electrode chip two 11, it can be used as a power source to drive the air pump 61 to start working.

[0023] In a preferred embodiment: The central axis of the bevel gear II 68 is rotatably sleeved on the inner wall of the fixing plate 69. The top of the fixing plate 69 is fixedly installed on the top inner wall of the air inlet pipe 2. The rotating shaft 66 and the bevel gear I 67 are perpendicularly arranged on the inner wall of the air inlet pipe 2, and the bevel gear I 67 is rotatably sleeved on the inner wall of the air inlet pipe 2.

[0024] In the above structure, driven by the air pump 61, air can be inflated into the inner cavity of the fan 65 through the air outlet pipe 64, thereby driving the fan 65 to rotate, enabling the fan 65 to drive the bevel gear I 67 to rotate synchronously, causing the meshing bevel gear II 68 to rotate, and enabling the bevel gear II 68 to drive the rotating rod 610 to rotate synchronously. At the same time, the installation position of the fixing plate 69 can limit the bevel gear II 68, effectively preventing the bevel gear II 68 from shifting in position during rotation.

[0025] In a preferred embodiment: A rotating rod 610 is fixedly sleeved at the center of the fixing plate 69. One end of the rotating rod 610 away from the fixing plate 69 is fixedly assembled with a driving gear 611. The outer wall of the driving gear 611 is respectively meshed with a toothed ring 612 and a rack 615. The outer wall of the toothed ring 612 is rotatably sleeved with a housing 613. The inner wall of the toothed ring 612 is meshed with a driving gear 614. The rack 615 is installed with a moving plate 617 through a mounting bolt 616, and a sealing ring 618 is fixedly assembled on the outer edge of the moving plate 617.

[0026] In the above structure, due to the linkage between the toothed ring 612, the driving gear 614, and the driving gear 611, when the toothed ring 612 rotates, it can drive the remaining five driving gears 614 to rotate simultaneously, enabling the six moving plates 617 of the device to move simultaneously, allowing it to ventilate quickly when opened and ensuring good sealing when closed.

[0027] In a preferred embodiment: The outer edge of the housing 613 is fixedly installed on the inner wall of the air inlet pipe 2. The shape of the housing 613 is a hollow ring. The driving gear 611 and the driving gear 614 are both rotatably connected to the inner wall of the housing 613. The diameter of the circle formed when the tips of the six moving plates 617 come into contact is adapted to the diameter of the air inlet pipe 2.

[0028] In a preferred embodiment: The number of driving gears 614 is five, and the five driving gears 614 and one driving gear 611 are evenly distributed on the inner wall of the toothed ring 612. The thickness of the toothed ring 612 plus the thickness of the rack 615 is equal to the thickness of the driving gear 611. The driving gear 611 and the driving gear 614 have the same shape. The number of racks 615 and moving plates 617 is six, and the six racks 615 and moving plates 617 are evenly distributed on the outer wall of the toothed ring 612.

[0029] In the above structure, the driving gear 611 rotates under the drive of the rotating rod 610, which can drive the toothed ring 612 to rotate on the inner wall of the housing 613, so that a plurality of driving gears 614 meshing with the toothed ring 612 start to rotate. Furthermore, the rack 615 can move along the direction of the driving gear 614 under the rotation of the driving gear 614, so that the vertices of the six moving plates 617 can be in contact with each other, thereby enabling it to divide the outside from the inner wall of the intake pipe 2, effectively preventing the outside air from continuing to enter the inner wall of the fuel cell stack main body 1, and effectively preventing the occurrence of gas waste.

[0030] In a preferred embodiment: The gas leakage marking assembly 8 includes a ventilation disk 81. A ventilation pipe 82 is fixedly assembled on the outer wall of the ventilation disk 81. Sealing plates 83 are installed at both ends of the ventilation disk 81. Display lamps 84 are installed on the outer walls of the sealing plates 83. Air outlet holes 85 are formed on the outer wall of the ventilation pipe 82 close to the ventilation disk 81. A gas collecting cylinder 86 is inlaid on the inner wall of the ventilation disk 81. A partition plate 87 is fixedly assembled on the inner wall of the ventilation disk 81. A gas detector 88 is arranged on the inner wall of the ventilation disk 81. An anti-backflow layer 89 is installed at the bottom of the ventilation pipe 82.

[0031] In a preferred embodiment: There are four groups of gas detectors 88, and the four groups of gas detectors 88 are all in contact with the leaked gas through the air outlet holes 85. An LED chip is arranged in the inner cavity of the gas detector 88, and the LED chip is electrically connected to the sealing plate 83 through a control circuit. The cross section of the partition plate 87 is in a "ten" shape, and the end of the connecting pipe 63 far from the gas transmission pipe 62 is located on the inner wall of the partition plate 87; In the above structure, the gas in the inner wall of the ventilation pipe 82 is discharged from the air outlet holes 85 to the inner wall of the ventilation disk 81, so that the corresponding gas can come into contact with the gas detector 88, thereby causing corresponding changes; When hydrogen comes into contact with the gas detector 88, a yellow-green change will occur, and the LED chip arranged in the inner cavity of the gas detector 88 will cause the sealing plate 83 to emit yellow-green light; And when oxygen comes into contact with the gas detector 88, a red change will occur, and the LED chip arranged in the inner cavity of the gas detector 88 will cause the sealing plate 83 to emit red light; When coolant vapor comes into contact with the gas detector 88, a dark brown change will occur, and the LED chip arranged in the inner cavity of the gas detector 88 will cause the sealing plate 83 to emit dark brown light; And when nitrogen comes into contact with the gas detector 88, a golden yellow change will occur, and the LED chip arranged in the inner cavity of the gas detector 88 will cause the sealing plate 83 to emit golden yellow light; Furthermore, the device can detect the overall sealing performance of the fuel cell stack main body 1, and at the same time, it can determine which ventilation pipe 82 has a leakage situation by the color of the illuminated sealing plate 83.

[0032] In a preferred embodiment: the cross-section of the anti-backflow layer 89 is curved, and the concave part of the curve is located on the inner wall of the air collecting cylinder 86. There are four ventilation pipes 82, and both ends of the four ventilation pipes 82 are in contact with the air inlet groove 4, the air outlet groove 5, and the ventilation disc 81 respectively. The top of the inner wall of the air collecting cylinder 86 is connected to the inner wall of the connecting pipe 63.

[0033] In the above structure, due to the characteristic that the top of the inner wall of the air collecting cylinder 86 is connected to the inner wall of the connecting pipe 63, it can be known that the leaked gas on the inner wall of the air collecting cylinder 86 can be transported through the leaked gas at the connecting pipe 63, so as to facilitate the detection of the leaked gas of the fuel cell stack main body 1, and it is convenient to repair the leakage point of the fuel cell stack main body 1 during the process.

[0034] Working principle: When detecting the airtightness of the fuel cell stack body 1, gas is transported to the inner wall of the fuel cell stack body 1 through the air inlet groove 4, enabling the gas to circulate through the air inlet groove 4 on the inner wall of the fuel cell stack body 1. And when the fuel cell stack body 1 has a gas leak, the leaked gas will enter the inner wall of the ventilation disc 81 through the ventilation pipe 82, so that the leaked gas can come into contact with the corresponding gas detector 88 after passing through the air outlet hole 85, thereby causing a corresponding color change. And an LED chip is arranged in the inner cavity of the gas detector 88 to make the sealing plate 83 emit light of a corresponding color. At the same time, the leaked gas will enter the inner wall of the air delivery pipe 62 because the top of the inner wall of the air collecting cylinder 86 is connected to the inner wall of the communicating pipe 63. And when the air collecting airbag 3 has collected enough gas, the air collecting airbag 3 will expand, so that the air collecting airbag 3 expands until the electrode chip one 9 on the outer wall contacts the electrode chip two 11. At this time, there will be an electric current passing through. And based on the characteristic that this electric current is electrically connected to the air pump 61 through the controller, it can be known that when the electrode chip one 9 contacts the electrode chip two 11, it can serve as a power source to drive the air pump 61 to start working. The air pump 61 can be driven to inflate the inner cavity of the fan 65 through the air outlet pipe 64, thereby driving the fan 65 to rotate. The fan 65 can drive the bevel gear one 67 to rotate synchronously, enabling the meshing bevel gear two 68 to rotate, and the bevel gear two 68 can drive the rotating rod 610 to rotate synchronously, driving the toothed ring 612 to rotate on the inner wall of the housing 613, making a plurality of driving gears 614 meshing with the toothed ring 612 start to rotate. Furthermore, the rack 615 can move along the direction of the driving gear 614 under the rotation of the driving gear 614, enabling the vertices of the six moving plates 617 to come into contact, thereby dividing the outside from the inner wall of the air inlet pipe 2, effectively preventing the outside air from continuing to enter the inner wall of the fuel cell stack body 1, and effectively preventing the occurrence of gas waste. The device can detect the overall airtightness of the fuel cell stack body 1 while also being able to promptly discover and repair potential leakage points.

[0035] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fuel cell stack airtightness detection device, comprising a fuel cell stack main body (1), characterized in that: An intake pipe (2) is installed on the outer wall of the fuel cell stack main body (1). A gas collecting airbag (3) is sleeved on the outer wall of the intake pipe (2). Intake grooves (4) and air outlet grooves (5) are formed at both ends of the fuel cell stack main body (1). An airtightness detection assembly (6) is arranged at the top of the intake pipe (2). A placement groove (7) is formed in the inner wall of the fuel cell stack main body (1). A gas leakage marking assembly (8) is arranged on the inner wall of the placement groove (7). An electrode chip one (9) is fixedly assembled at one end of the gas collecting airbag (3) close to the intake pipe (2). A limiting block (10) is fixedly installed at the top of the intake pipe (2). An electrode chip two (11) is fixedly installed at one end of the limiting block (10) close to the gas collecting airbag (3). The airtightness detection assembly (6) includes an air pump (61). One end of an air delivery pipe (62) is installed at the top of the air pump (61), and the other end of the air delivery pipe (62) is fixedly assembled with a connecting pipe (63). The output end of the air pump (61) is fixedly assembled with an air outlet pipe (64). A fan (65) is fixedly installed at the bottom of the air outlet pipe (64). A rotating shaft (66) is fixedly installed at the bottom of the fan (65). A bevel gear one (67) is fixedly assembled at the bottom of the rotating shaft (66). A bevel gear two (68) is meshed with the outer wall of the bevel gear one (67). A fixing plate (69) is installed on the outer wall of the bevel gear two (68).

2. The airtightness detection device for a fuel cell stack according to claim 1, wherein: The electrode chip one (9) and the electrode chip two (11) have the same shape, and the virtual center lines of the electrode chip one (9) and the electrode chip two (11) coincide. When the electrode chip one (9) contacts the electrode chip two (11), a current will be generated, and this current is electrically connected to the air pump (61) through a controller. The gas collecting airbag (3) is arranged in a ring between the intake pipe (2) and the fuel cell stack main body (1).

3. The airtightness detection device for a fuel cell stack according to claim 1, wherein: The central axis of the bevel gear two (68) is rotatably sleeved in the inner wall of the fixing plate (69). The top of the fixing plate (69) is fixedly installed on the top inner wall of the intake pipe (2). The rotating shaft (66) and the bevel gear one (67) are perpendicularly arranged in the inner wall of the intake pipe (2). The bevel gear one (67) is rotatably sleeved in the inner wall of the intake pipe (2).

4. A fuel cell stack airtightness detection device according to claim 3, characterized in that: A rotating rod (610) is fixedly sleeved at the center of the fixing plate (69). A driving gear (611) is fixedly assembled at one end of the rotating rod (610) away from the fixing plate (69). A toothed ring (612) and a rack (615) are respectively meshed with the outer wall of the driving gear (611). The outer wall of the toothed ring (612) is rotatably sleeved with a housing (613). A driving gear (614) is meshed with the inner wall of the toothed ring (612). The rack (615) is installed with a moving plate (617) through a mounting bolt (616). A sealing ring (618) is fixedly assembled on the outer edge of the moving plate (617).

5. The airtightness detection device for a fuel cell stack according to claim 4, characterized in that: The outer edge of the housing (613) is fixedly installed on the inner wall of the intake pipe (2). The housing (613) is in the shape of a hollow ring. The driving gear (611) and the driven gear (614) are both rotatably connected to the inner wall of the housing (613). The diameter of the circle formed when the tips of the six moving plates (617) are in contact is adapted to the diameter of the intake pipe (2).

6. The airtightness detection device for a fuel cell stack according to claim 5, characterized in that: There are five driven gears (614), and the five driven gears (614) and one driving gear (611) are evenly distributed on the inner wall of the toothed ring (612). The sum of the thickness of the toothed ring (612) and the thickness of the rack (615) is equal to the thickness of the driving gear (611). The driving gear (611) and the driven gear (614) have the same shape. The number of the racks (615) and the moving plates (617) is six, and the six racks (615) and the moving plates (617) are evenly distributed on the outer wall of the toothed ring (612).

7. A fuel cell stack airtightness detection device according to claim 1, characterized in that: The gas leakage marking assembly (8) includes a ventilation disc (81). A ventilation pipe (82) is fixedly assembled on the outer wall of the ventilation disc (81). Sealing plates (83) are installed at both ends of the ventilation disc (81). Display lamps (84) are installed on the outer walls of the sealing plates (83). Air outlet holes (85) are formed on the outer wall of the ventilation pipe (82) close to the ventilation disc (81). An air collecting cylinder (86) is inlaid on the inner wall of the ventilation disc (81). A partition plate (87) is fixedly assembled on the inner wall of the ventilation disc (81). A gas detector (88) is arranged on the inner wall of the ventilation disc (81). An anti-backflow layer (89) is installed at the bottom of the ventilation pipe (82). One end of the connecting pipe (63) away from the gas transmission pipe (62) is located on the inner wall of the partition plate (87).

8. The airtightness detection device for a fuel cell stack according to claim 7, characterized in that: There are four groups of gas detectors (88), and the four groups of gas detectors (88) are all in contact with the leaked gas through the air outlet holes (85). An LED chip is arranged in the inner cavity of the gas detector (88), and the LED chip is electrically connected to the sealing plate (83) through a control circuit. The cross section of the partition plate (87) is in the shape of a "plus" sign.

9. The airtightness detection device for a fuel cell stack according to claim 8, characterized in that: The cross section of the anti-backflow layer (89) is in an arc shape, and the concave part of the arc is located on the inner wall of the air collecting cylinder (86). There are four ventilation pipes (82), and both ends of the four ventilation pipes (82) are in contact with the air inlet groove (4), the air outlet groove (5) and the ventilation disc (81) respectively.

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