Cathode closed type air-cooled fuel cell for unmanned aerial vehicle and working method thereof

Abstract

The invention relates to a cathode closed type air-cooled fuel cell for an unmanned aerial vehicle and a working method of the cathode closed type air-cooled fuel cell. The fuel cell comprises a hydrogen supply subsystem, an oxygen supply subsystem, a cooling path subsystem and an electric pile, the hydrogen supply subsystem and the oxygen supply subsystem complete heat exchange between liquid hydrogen and high-temperature air through a liquid hydrogen vaporizer, and the effects of liquid hydrogen vaporization and high-temperature air cooling are achieved. By arranging the first vortex tube to replace a traditional pressure reducing valve, potential energy of vaporized high-pressure hydrogen is recovered by the first vortex tube, the vaporized high-pressure hydrogen is separated into cold flow and hot flow in the first vortex tube, and the hot flow partially enters an end plate of the galvanic pile to heat the end plate, so that the temperature distribution in the galvanic pile is optimized, and the voltage consistency between single cells is improved; therefore, the performance and durability of the stack are improved. When the fuel cell is used for the unmanned aerial vehicle, the fan of the fuel cell is also used as a propeller of the unmanned aerial vehicle, so that the system integration level is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a cathode closed air-cooled fuel cell for an unmanned aerial vehicle and a working method thereof. Background Art

[0002] Fuel cells have the advantages of high efficiency, environmental protection and sustainability, so they are being used more and more widely. Existing drones often choose cathode open air-cooled fuel cells as their power source because they also have the characteristics of simple structure, low cost and good portability.

[0003] However, there are still some problems when cathode open air-cooled fuel cells are used in drones: the air pressure at the cathode of the stack is low, which results in the stack performance not being fully utilized, and usually poor performance and efficiency; the water produced by the stack is difficult to collect, and cathode humidification is usually not possible, and long-term dry operation leads to low durability of the stack; cathode open stacks generally use fans for heat dissipation. Due to the uneven heat dissipation of the fan, the temperature in the stack is uneven and the temperature gradient is large, resulting in extremely uneven voltage between single cells, seriously affecting the performance and durability of the stack.

[0004] In addition, the anode gas source of air-cooled fuel cells is generally selected from high-pressure hydrogen bottles, which are usually equipped with pressure reducing valves to directly reduce the pressure and supply hydrogen, resulting in a waste of hydrogen potential energy.

[0005] Therefore, it is urgent to design a cathode closed air-cooled fuel cell for UAV and its working method to solve the problems existing in the above-mentioned prior art. Summary of the invention

[0006] In view of this, the present invention provides a cathode closed air-cooled fuel cell for unmanned aerial vehicles and a working method thereof, the purpose of which is to achieve cathode humidification, improve the heat dissipation effect of the fuel cell stack, and enhance the performance of the fuel cell stack by optimizing the structure of the fuel cell hydrogen supply subsystem, oxygen supply subsystem and cooling circuit subsystem.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A cathode closed air-cooled fuel cell for a drone, the fuel cell comprising a hydrogen supply subsystem, an oxygen supply subsystem, a cooling circuit subsystem and a fuel cell stack;

[0009] The hydrogen supply subsystem includes a liquid hydrogen bottle, a liquid hydrogen valve, a liquid hydrogen vaporizer, a first vortex tube, a one-way valve and a hydrogen tail exhaust valve. The outlet of the liquid hydrogen bottle is provided with a liquid hydrogen valve for controlling whether the liquid hydrogen in the liquid hydrogen bottle flows out. The outlet of the liquid hydrogen valve is connected to the liquid hydrogen inlet of the liquid hydrogen vaporizer, and the hydrogen outlet of the liquid hydrogen vaporizer is connected to the inlet of the first vortex tube. The hot flow outlet of the first vortex tube is connected to the end plate inlet of the stack through a pipeline; the cold flow outlet of the first vortex tube is connected to the anode inlet of the stack through a pipeline; the end plate outlet of the stack is connected to the pipeline between the cold flow outlet of the first vortex tube and the anode inlet of the stack through a pipeline, and a one-way valve is provided on the pipeline of the end plate outlet of the stack; the pipeline of the anode outlet of the stack is provided with a hydrogen tail exhaust valve;

[0010] The oxygen supply subsystem includes an air filter, a small air compressor, a membrane humidifier, a second vortex tube and an air tail valve. The air filter is connected to the small air compressor and the heat source inlet of the liquid hydrogen vaporizer in sequence, the heat source outlet of the liquid hydrogen vaporizer is connected to the humidification side inlet of the membrane humidifier, the humidification side outlet of the membrane humidifier is connected to the cathode inlet of the fuel cell stack, the cathode outlet of the fuel cell stack is connected to the second vortex tube, the hot flow outlet of the second vortex tube is connected to the moisture supply side inlet of the membrane humidifier, and the moisture supply side outlet of the membrane humidifier is connected to the air tail valve; the cold flow outlet of the second vortex tube is connected to the cooling path inlet of the fuel cell stack through a pipeline.

[0011] Furthermore, the cooling circuit subsystem includes a water reservoir, a water pump, an atomizing nozzle and a fan. The liquid outlet of the water reservoir is connected to the atomizing nozzle through a pipe. A water pump is provided on the connecting pipe between the water reservoir and the atomizing nozzle. The atomizing nozzle is provided above the cooling circuit inlet of the battery stack. A fan is provided directly below the cooling circuit outlet of the battery stack. When the blades of the fan rotate, the gas and liquid used to cool the battery stack are sucked in from the cooling circuit inlet and flow out from the cooling circuit outlet.

[0012] Furthermore, the pipe at the anode outlet of the fuel cell stack is connected to the liquid inlet of the water reservoir. When the anode of the fuel cell stack is purged, the hydrogen tail valve is opened, and the liquid water produced by the anode of the fuel cell stack enters the water reservoir.

[0013] Furthermore, the air tail exhaust valve is a steering tail exhaust valve, and during the operation of the fuel cell, the direction of the tail exhaust outlet of the air tail exhaust valve is changed according to conditions.

[0014] Furthermore, the fan includes four blades, namely blade A, blade B, blade C and blade D. The four blades are evenly distributed around the center of the fan. Blade A and blade D are the first group of blades and blade A and blade D are relatively arranged. Blade B and blade C are the second group of blades and blade B and blade C are relatively arranged. When the fuel cell is used in a drone, the fan also serves as a propeller of the drone.

[0015] The present invention also provides a working method based on the above-mentioned cathode closed air-cooled fuel cell for unmanned aerial vehicles, and the working method comprises:

[0016] The liquid hydrogen valve is opened, and the high-pressure liquid hydrogen in the liquid hydrogen bottle flows in through the liquid hydrogen inlet of the liquid hydrogen vaporizer, and is vaporized into high-pressure hydrogen in the liquid hydrogen vaporizer. The high-pressure hydrogen flows out through the hydrogen outlet of the liquid hydrogen vaporizer and enters the first vortex tube. The vaporized high-pressure hydrogen is recovered by the first vortex tube for potential energy, and is separated into a cold flow and a hot flow in the first vortex tube. The hot flow flows out from the hot flow outlet of the first vortex tube, enters the end plate through the end plate inlet of the stack, and heats the end plate; the cold flow flows out from the cold flow outlet of the first vortex tube, enters the stack through the anode inlet of the stack to participate in the reaction; the anode product is controlled by the hydrogen tail valve to be discharged;

[0017] After being compressed by a small air compressor, the air enters the air filter to filter out harmful gases and impurities. The compressed and filtered high-temperature air enters through the heat source inlet of the liquid hydrogen vaporizer, completes heat exchange with liquid hydrogen in the liquid hydrogen vaporizer, and the liquid hydrogen is vaporized into hydrogen. After the high-temperature air is cooled, it flows out through the heat source outlet of the liquid hydrogen vaporizer and enters the humidification side of the membrane humidifier to complete humidification. Then, it enters the battery stack from the cathode inlet to participate in the reaction. The cathode outflow gas enters the second vortex tube and is separated into a cold flow and a hot flow. The hot flow part is a high-temperature gas containing water vapor, and the cold flow part is a mixture of low-temperature gas and liquid water. The hot flow part flows out from the hot flow outlet of the second vortex tube, enters the humidification side of the membrane humidifier, provides water vapor for the air on the humidification side, and then flows out from the humidification side outlet of the membrane humidifier and is discharged out of the system through the air tail valve; the cold flow part flows out from the cold flow outlet of the second vortex tube and flows to the cooling path inlet of the battery stack through the pipeline.

[0018] Furthermore, the hot flow portion flowing out from the hot flow outlet of the first vortex tube flows out from the end plate outlet of the fuel cell stack, passes through the one-way valve, merges with the cold flow portion flowing out from the cold flow outlet of the first vortex tube, and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction.

[0019] Furthermore, the fan blades rotate to generate airflow, which draws air from the cooling path inlet, enters the cooling channel of the battery stack to cool and dissipate the heat of the battery stack, and then flows out from the cooling path outlet; at the same time, the water pump pumps out the water in the water reservoir, atomizes it through the atomizing nozzle and sprays it to the cooling path inlet of the battery stack, and the cold flow part flows out from the cold flow outlet of the second vortex tube, and flows to the cooling path inlet of the battery stack through the pipeline; under the action of the fan, the mist liquid water sprayed by the atomizing nozzle and the cold flow part flowing out from the cold flow outlet of the second vortex tube are all sucked into the cooling path of the battery stack.

[0020] Furthermore, it is characterized in that the anode of the fuel cell adopts a dead-end mode, and the anode outlet is opened and closed by a hydrogen tail exhaust valve. Under normal circumstances, the hydrogen tail exhaust valve is in a closed state. When the liquid water and exhaust gas in the stack accumulate to a certain level, the hydrogen tail exhaust valve is opened to realize the stack anode purge, and the liquid water and exhaust gas are discharged through the pressure difference. The liquid water enters the water reservoir, and the exhaust gas is discharged from the hydrogen supply subsystem.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The high-temperature air compressed by a small air compressor is used as the heat source of the liquid hydrogen vaporizer to vaporize the liquid hydrogen in the liquid hydrogen vaporizer, and at the same time, the high-temperature air is cooled to improve energy utilization; by setting a first vortex tube to replace the traditional pressure reducing valve, the vaporized high-pressure hydrogen is recovered by the first vortex tube to recover potential energy, and is separated into cold flow and hot flow in the first vortex tube. The hot flow enters the end plate of the stack to heat the end plate, thereby optimizing the temperature distribution in the stack and improving the voltage consistency between single cells, thereby improving the performance and durability of the stack. When this fuel cell is used in a drone, the fan of the fuel cell also serves as the propeller of the drone, increasing the system integration.

[0023] (2) By designing a water reservoir to collect the tail water of the anode of the stack, and using an atomizing nozzle to spray the tail water into the cooling channel of the stack, the heat dissipation capacity of the stack is effectively enhanced; by designing a second vortex tube, the cathode gas out of the stack enters the second vortex tube and is separated into cold flow and hot flow, of which the cold flow flows to the cooling path entrance of the stack and is sucked into the cooling channel of the stack under the action of the fan, further improving the heat dissipation capacity of the stack. The hot flow separated by the second vortex tube enters the humidification side of the membrane humidifier, providing water vapor for the humidification side air and providing a water source for humidification of the air entering the stack; the air tail exhaust valve is set so that the direction of the tail exhaust outlet can be changed according to the conditions, and the direction of the air tail exhaust valve is adjusted according to the flight status and flight direction of the drone, thereby collecting the kinetic energy in the tail exhaust gas.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 The schematic diagram of the structure of the cathode closed air-cooled fuel cell for a drone according to an embodiment of the present invention is shown;

[0027] Figure 2 A schematic diagram of the fan structure of an air-cooled fuel cell according to an embodiment of the present invention is shown.

[0028] In the figure: 1. Hydrogen bottle; 2. Liquid hydrogen valve; 3. Liquid hydrogen vaporizer; 4. Air filter; 5. Small air compressor; 6. First vortex tube; 7. One-way valve; 8. Membrane humidifier; 9. Air tail exhaust valve; 10. Fuel cell; 11. Atomizing nozzle; 12. Fan; 13. Water pump; 14. Hydrogen tail exhaust valve; 15. Water reservoir; 16. Second vortex tube. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The embodiment of the present invention provides a cathode closed air-cooled fuel cell for a drone, as shown in the attached Figure 1 As shown, the fuel cell includes a hydrogen supply subsystem, an oxygen supply subsystem, a cooling circuit subsystem and a fuel cell stack 10;

[0031] The hydrogen supply subsystem includes a liquid hydrogen bottle 1, a liquid hydrogen valve 2, a liquid hydrogen vaporizer 3, a first vortex tube 6, a one-way valve 7 and a hydrogen tail exhaust valve 14. The outlet of the liquid hydrogen bottle 1 is provided with a liquid hydrogen valve 2 for controlling whether the liquid hydrogen in the liquid hydrogen bottle 1 flows out. The outlet of the liquid hydrogen valve 2 is connected to the liquid hydrogen inlet of the liquid hydrogen vaporizer 3, and the hydrogen outlet of the liquid hydrogen vaporizer 3 is connected to the inlet of the first vortex tube 6. The hot flow outlet of the first vortex tube 6 is connected to the end plate inlet of the stack 10 through a pipeline; the cold flow outlet of the first vortex tube 6 is connected to the anode inlet of the stack 10 through a pipeline; the end plate outlet of the stack 10 is connected to the pipeline between the cold flow outlet of the first vortex tube 6 and the anode inlet of the stack 10 through a pipeline, and a one-way valve 7 is provided on the pipeline of the end plate outlet of the stack 10 to prevent the gas flowing out of the cold flow outlet of the first vortex tube 6 from entering the end plate of the stack 10 through this pipeline; the pipeline of the anode outlet of the stack 10 is provided with a hydrogen tail exhaust valve 14;

[0032] The oxygen supply subsystem includes an air filter 4, a small air compressor 5, a membrane humidifier 8, a second vortex tube 16 and an air tail valve 9, the air filter 4 is connected to the small air compressor 5 and the heat source inlet of the liquid hydrogen vaporizer 3 in sequence, the heat source outlet of the liquid hydrogen vaporizer 3 is connected to the humidification side inlet of the membrane humidifier 8, the humidification side outlet of the membrane humidifier 8 is connected to the cathode inlet of the stack 10, the cathode outlet of the stack 10 is connected to the second vortex tube 16, the hot flow outlet of the second vortex tube 16 is connected to the moisture supply side inlet of the membrane humidifier 8, and the moisture supply side outlet of the membrane humidifier 8 is connected to the air tail valve 9; the cold flow outlet of the second vortex tube 16 is connected to the cooling path inlet of the stack 10 through a pipeline;

[0033] The cooling circuit subsystem includes a water reservoir 15, a water pump 13, an atomizing nozzle 11 and a fan 12. The liquid outlet of the water reservoir 15 is connected to the atomizing nozzle 11 through a pipe. The water pump 13 is arranged on the connecting pipe between the water reservoir 15 and the atomizing nozzle 11. The atomizing nozzle 11 is arranged above the cooling circuit inlet of the battery stack 10. The fan 12 is arranged directly below the cooling circuit outlet of the battery stack 10. When the blades of the fan 12 rotate, the gas and liquid used to cool the battery stack are sucked in from the cooling circuit inlet and flow out from the cooling circuit outlet.

[0034] The pipe at the anode outlet of the stack 10 is connected to the liquid inlet of the water reservoir 15 . When the stack anode is purged, the hydrogen tail valve 14 is opened, and the liquid water produced by the stack anode enters the water reservoir 15 .

[0035] The air tail exhaust valve 9 is a steering tail exhaust valve. During the operation of the fuel cell, the tail exhaust outlet direction of the air tail exhaust valve 9 is changed according to the conditions.

[0036] like Figure 2 As shown, the fan 12 includes four blades, namely blade A, blade B, blade C and blade D. The four blades are evenly distributed around the center of the fan, blade A and blade D are the first group of blades and blade A and blade D are relatively arranged, blade B and blade C are the second group of blades and blade B and blade C are relatively arranged. When the fuel cell is used for a drone, the fan 12 also serves as a propeller of the drone, and is arranged so that the first group of blades and the second group of blades rotate in opposite directions to offset the angular momentum of the blade rotation and generate downward thrust at the same time.

[0037] As one of the embodiments, when blades A and D in the first group of blades rotate clockwise to generate downward thrust, blades B and C in the second group of blades are set to rotate counterclockwise to generate downward thrust. When the drone needs to rotate clockwise, the speed of the second group of blades increases, and the speed of the first group of blades decreases. The clockwise angular momentum generated makes the drone rotate clockwise, and the steering speed is controlled by adjusting the speed difference between the two groups of fans. The airflow generated when the blades rotate will bring the gas at the entrance of the cooling path into the cooling flow path of the battery stack 10 to achieve battery stack cooling.

[0038] The embodiment of the present invention further proposes a working method based on the above-mentioned cathode closed air-cooled fuel cell for drone, and the working method comprises:

[0039] The liquid hydrogen valve 2 is opened, and the high-pressure liquid hydrogen in the liquid hydrogen bottle 1 flows in through the liquid hydrogen inlet of the liquid hydrogen vaporizer 3, and is vaporized into high-pressure hydrogen in the liquid hydrogen vaporizer 3. The high-pressure hydrogen flows out through the hydrogen outlet of the liquid hydrogen vaporizer 3 and enters the first vortex tube 6. The vaporized high-pressure hydrogen is recovered by the first vortex tube 6 for potential energy, and is separated into a cold flow and a hot flow in the first vortex tube. The hot flow flows out from the hot flow outlet of the first vortex tube 6, enters the end plate through the end plate inlet of the stack 10, and heats the end plate; the cold flow flows out from the cold flow outlet of the first vortex tube 6, enters the stack through the anode inlet of the stack 10 to participate in the reaction; the anode product is controlled by the hydrogen tail valve 14 to be discharged;

[0040] The hot flow part flowing out of the hot flow outlet of the first vortex tube 6 flows out from the end plate outlet of the fuel cell stack 10, passes through the one-way valve 7, merges with the cold flow part flowing out of the cold flow outlet of the first vortex tube 6, and enters the fuel cell stack through the anode inlet of the fuel cell stack 10 to participate in the reaction;

[0041] After being compressed by the small air compressor 5, the air enters the air filter 4 to filter out harmful gases and impurities. The compressed and filtered high-temperature air enters through the heat source inlet of the liquid hydrogen vaporizer 3, completes heat exchange with liquid hydrogen in the liquid hydrogen vaporizer 3, and the liquid hydrogen is vaporized into hydrogen. After the high-temperature air is cooled, it flows out through the heat source outlet of the liquid hydrogen vaporizer 3 and enters the humidification side of the membrane humidifier 8 to complete humidification. Then, it enters the battery stack from the cathode inlet of the battery stack 10 to participate in the reaction. The gas out of the cathode enters the second vortex tube 16 and is Separated into cold flow and hot flow, the hot flow part is high-temperature gas containing water vapor, and the cold flow part is a mixture of low-temperature gas and liquid water. The hot flow part flows out from the hot flow outlet of the second vortex tube 16, enters the humidification side of the membrane humidifier 8, provides water vapor for the air on the humidification side, and then flows out from the humidification side outlet of the membrane humidifier 8 and is discharged from the system through the air tail valve 9; the cold flow part flows out from the cold flow outlet of the second vortex tube 16, and flows to the cooling path inlet of the stack 10 through the pipeline;

[0042] The blades of the fan 12 rotate to generate airflow, which draws air from the cooling path inlet, enters the cooling flow channel of the battery stack 10 to cool the battery stack, and then flows out from the cooling path outlet; at the same time, the water pump 13 pumps out the water in the water reservoir 15, and sprays the water to the cooling path inlet of the battery stack 10 after being atomized by the atomizing nozzle 11, and the cold flow part flows out from the cold flow outlet of the second vortex tube 16, and flows to the cooling path inlet of the battery stack 10 through the pipeline; under the action of the fan 12, the mist liquid water sprayed by the atomizing nozzle 11 and the cold flow part flowing out from the cold flow outlet of the second vortex tube 16 are all sucked into the cooling flow channel of the battery stack 10, which helps to improve the heat dissipation capacity of the battery stack 10.

[0043] During the operation of the fuel cell, the direction of the tail exhaust outlet of the air tail exhaust valve 9 changes according to the conditions. Specifically, when the UAV is hovering, the outlet direction of the air tail exhaust valve 9 is adjusted vertically downward, and when the UAV is moving forward, the outlet direction of the air tail exhaust valve 9 is adjusted to be opposite to the forward direction. The above setting can collect kinetic energy in the tail exhaust gas.

[0044] The anode of the fuel cell adopts a dead-end mode, and the anode outlet is opened and closed by a hydrogen tail valve 14. Normally, the hydrogen tail valve 14 is in a closed state. When the liquid water and exhaust gas in the stack accumulate to a certain level, the hydrogen tail valve 14 is opened to realize the stack anode purge, and the liquid water and exhaust gas are discharged through the pressure difference. The liquid water enters the water reservoir 15, and the exhaust gas is discharged from the hydrogen supply subsystem.

[0045] The high-temperature air compressed by a small air compressor is used as the heat source of the liquid hydrogen vaporizer to vaporize the liquid hydrogen in the liquid hydrogen vaporizer, and at the same time, the high-temperature air is cooled to improve energy utilization. By setting the first vortex tube to replace the traditional pressure reducing valve, the vaporized high-pressure hydrogen is recovered by the first vortex tube. The potential energy is separated into cold flow and hot flow in the first vortex tube. The hot flow enters the end plate of the stack to heat the end plate, thereby optimizing the temperature distribution in the stack and improving the voltage consistency between single cells, thereby improving the performance and durability of the stack. When this fuel cell is used in a drone, the fan of the fuel cell also serves as the propeller of the drone, increasing the system integration.

[0046] By designing a water reservoir to collect the tail water of the anode of the stack, and using an atomizing nozzle to spray the tail water into the cooling channel of the stack, the heat dissipation capacity of the stack is effectively enhanced; by designing the second vortex tube, the cathode gas out of the stack enters the second vortex tube and is separated into cold flow and hot flow, of which the cold flow flows to the cooling path entrance of the stack and is sucked into the cooling channel of the stack under the action of the fan, further improving the heat dissipation capacity of the stack. The hot flow separated by the second vortex tube enters the humidification side of the membrane humidifier, providing water vapor for the air on the humidification side and providing a water source for humidification of the air entering the stack; the air tail exhaust valve is set so that the direction of the tail exhaust outlet can be changed according to the conditions, and the direction of the air tail exhaust valve is adjusted according to the flight status and flight direction of the drone, thereby collecting the kinetic energy in the tail exhaust gas.

[0047] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cathode closed air-cooled fuel cell for an unmanned aerial vehicle, characterized in that: The fuel cell comprises a hydrogen supply subsystem, an oxygen supply subsystem, a cooling circuit subsystem and a fuel cell stack; The hydrogen supply subsystem includes a liquid hydrogen bottle, a liquid hydrogen valve, a liquid hydrogen vaporizer, a first vortex tube, a one-way valve and a hydrogen tail exhaust valve. The outlet of the liquid hydrogen bottle is provided with a liquid hydrogen valve for controlling whether the liquid hydrogen in the liquid hydrogen bottle flows out. The outlet of the liquid hydrogen valve is connected to the liquid hydrogen inlet of the liquid hydrogen vaporizer, and the hydrogen outlet of the liquid hydrogen vaporizer is connected to the inlet of the first vortex tube. The hot flow outlet of the first vortex tube is connected to the end plate inlet of the stack through a pipeline; the cold flow outlet of the first vortex tube is connected to the anode inlet of the stack through a pipeline; the end plate outlet of the stack is connected to the pipeline between the cold flow outlet of the first vortex tube and the anode inlet of the stack through a pipeline, and a one-way valve is provided on the pipeline of the end plate outlet of the stack; the pipeline of the anode outlet of the stack is provided with a hydrogen tail exhaust valve; The oxygen supply subsystem includes an air filter, a small air compressor, a membrane humidifier, a second vortex tube and an air tail valve. The air filter is connected to the small air compressor and the heat source inlet of the liquid hydrogen vaporizer in sequence, the heat source outlet of the liquid hydrogen vaporizer is connected to the humidification side inlet of the membrane humidifier, the humidification side outlet of the membrane humidifier is connected to the cathode inlet of the fuel cell stack, the cathode outlet of the fuel cell stack is connected to the second vortex tube, the hot flow outlet of the second vortex tube is connected to the moisture supply side inlet of the membrane humidifier, and the moisture supply side outlet of the membrane humidifier is connected to the air tail valve; the cold flow outlet of the second vortex tube is connected to the cooling path inlet of the fuel cell stack through a pipeline.

2. The cathode closed air-cooled fuel cell for a drone as claimed in claim 1, characterized in that: The cooling circuit subsystem includes a water reservoir, a water pump, an atomizing nozzle and a fan. The liquid outlet of the water reservoir is connected to the atomizing nozzle through a pipe. A water pump is arranged on the connecting pipe between the water reservoir and the atomizing nozzle. The atomizing nozzle is arranged above the cooling circuit inlet of the battery stack. A fan is arranged directly below the cooling circuit outlet of the battery stack. When the blades of the fan rotate, the gas and liquid used to cool the battery stack are sucked in from the cooling circuit inlet and flow out from the cooling circuit outlet.

3. The cathode closed air-cooled fuel cell for a drone as claimed in claim 2, characterized in that: The pipe at the anode outlet of the fuel cell stack is connected to the liquid inlet of the water reservoir. When the anode of the fuel cell stack is purged, the hydrogen tail valve is opened and the liquid water produced by the anode of the fuel cell stack enters the water reservoir.

4. The cathode closed air-cooled fuel cell for drone according to claim 1, characterized in that: The air tail exhaust valve is a steering tail exhaust valve. During the operation of the fuel cell, the tail exhaust outlet direction of the air tail exhaust valve is changed according to the conditions.

5. The cathode closed air-cooled fuel cell for drone as claimed in claim 1, characterized in that: The fan includes four blades, namely blade A, blade B, blade C and blade D. The four blades are evenly distributed around the center of the fan. Blade A and blade D are the first group of blades and blade A and blade D are arranged opposite to each other. Blade B and blade C are the second group of blades and blade B and blade C are arranged opposite to each other. When the fuel cell is used for a drone, the fan also serves as a propeller of the drone.

6. A method for operating a cathode closed air-cooled fuel cell for a drone according to any one of claims 1 to 5, characterized in that: The working method comprises: The liquid hydrogen valve is opened, and the high-pressure liquid hydrogen in the liquid hydrogen bottle flows in through the liquid hydrogen inlet of the liquid hydrogen vaporizer, and is vaporized into high-pressure hydrogen in the liquid hydrogen vaporizer. The high-pressure hydrogen flows out through the hydrogen outlet of the liquid hydrogen vaporizer and enters the first vortex tube. The vaporized high-pressure hydrogen is recovered by the first vortex tube for potential energy, and is separated into a cold flow and a hot flow in the first vortex tube. The hot flow flows out from the hot flow outlet of the first vortex tube, enters the end plate through the end plate inlet of the stack, and heats the end plate; the cold flow flows out from the cold flow outlet of the first vortex tube, enters the stack through the anode inlet of the stack to participate in the reaction; the anode product is controlled by the hydrogen tail valve to be discharged; After being compressed by a small air compressor, the air enters the air filter to filter out harmful gases and impurities. The compressed and filtered high-temperature air enters through the heat source inlet of the liquid hydrogen vaporizer, completes heat exchange with liquid hydrogen in the liquid hydrogen vaporizer, and the liquid hydrogen is vaporized into hydrogen. After the high-temperature air is cooled, it flows out through the heat source outlet of the liquid hydrogen vaporizer and enters the humidification side of the membrane humidifier to complete humidification. Then, it enters the battery stack from the cathode inlet to participate in the reaction. The cathode outflow gas enters the second vortex tube and is separated into a cold flow and a hot flow. The hot flow part is a high-temperature gas containing water vapor, and the cold flow part is a mixture of low-temperature gas and liquid water. The hot flow part flows out from the hot flow outlet of the second vortex tube, enters the humidification side of the membrane humidifier, provides water vapor for the air on the humidification side, and then flows out from the humidification side outlet of the membrane humidifier and is discharged out of the system through the air tail valve; the cold flow part flows out from the cold flow outlet of the second vortex tube and flows to the cooling path inlet of the battery stack through the pipeline.

7. The operating method of the cathode closed air-cooled fuel cell for an unmanned aerial vehicle as claimed in claim 6, characterized in that: The hot flow portion flowing out from the hot flow outlet of the first vortex tube flows out from the end plate outlet of the fuel cell stack, passes through the one-way valve, merges with the cold flow portion flowing out from the cold flow outlet of the first vortex tube, and enters the fuel cell stack through the anode inlet of the fuel cell stack to participate in the reaction.

8. The operating method of the cathode closed air-cooled fuel cell for an unmanned aerial vehicle as claimed in claim 7, characterized in that: The fan blades rotate to generate airflow, which draws air from the cooling path inlet, enters the cooling flow channel of the battery stack to cool and dissipate the heat of the battery stack, and then flows out from the cooling path outlet; at the same time, the water pump pumps out the water in the water reservoir, atomizes it through the atomizing nozzle and sprays it to the cooling path inlet of the battery stack, and the cold flow part flows out from the cold flow outlet of the second vortex tube, and flows to the cooling path inlet of the battery stack through the pipeline; under the action of the fan, the mist liquid water sprayed by the atomizing nozzle and the cold flow part flowing out from the cold flow outlet of the second vortex tube are all sucked into the cooling flow channel of the battery stack.

9. The operating method of the cathode closed air-cooled fuel cell for an unmanned aerial vehicle as claimed in claim 8, characterized in that: The anode of the fuel cell adopts a dead-end mode, and the anode outlet is opened and closed by a hydrogen tail exhaust valve. Under normal circumstances, the hydrogen tail exhaust valve is in a closed state. When the liquid water and exhaust gas in the stack accumulate to a certain level, the hydrogen tail exhaust valve is opened to achieve stack anode purge, and the liquid water and exhaust gas are discharged through the pressure difference. The liquid water enters the water reservoir, and the exhaust gas is discharged from the hydrogen supply subsystem.

Images