Fuel cell system, self-pressurization method and vehicle

Abstract

The invention relates to a fuel cell system, a self-pressurization method and a vehicle. The hydrogen inlet pipeline is arranged at an anode inlet of the galvanic pile, a liquid hydrogen bottle is arranged on the hydrogen inlet pipeline, and a first heat exchanger is arranged in the liquid hydrogen bottle; the gas-liquid separator is arranged at an anode outlet of the electric pile; and the self-pressurization pipeline is connected with a gas output port of the gas-liquid separator, and the self-pressurization pipeline is further connected to the hydrogen inlet pipeline through the first heat exchanger. According to the fuel cell system, the self-pressurization method and the vehicle, when the pressure of the gas pillow area in the liquid hydrogen bottle is relatively low, unreacted hydrogen at the anode outlet of the electric pile can be re-introduced into the first heat exchanger in the liquid hydrogen bottle through the control assembly; the heat of the part of hydrogen and the liquid hydrogen in the liquid hydrogen bottle are utilized for heat exchange, so that self-pressurization of the pressure of the air pillow area in the liquid hydrogen bottle is achieved, the efficiency of pressure increase of the air pillow area is guaranteed, meanwhile, liquid hydrogen supply interruption caused by pressure fluctuation can be avoided, and it is guaranteed that the liquid hydrogen can flow out stably.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, in particular to a fuel cell system, a self-pressurization method and a vehicle. BACKGROUND

[0002] With the development of new energy technology, vehicle-mounted hydrogen fuel cell systems have attracted widespread attention due to their high efficiency, zero emissions and other advantages. Traditional vehicle-mounted hydrogen storage methods often use high-pressure gas cylinders for storage. However, this method has a low hydrogen storage density and cannot fully meet the long endurance requirements of vehicles. Therefore, vehicle-mounted liquid hydrogen storage systems have become a research hotspot. In a liquid hydrogen cylinder, there are both gas and liquid phases of hydrogen, with the gas phase being referred to as a gas pillow area and the liquid phase being referred to as a liquid hydrogen area. During hydrogen supply, the liquid hydrogen flows out by using a self-pressurization method in the cylinder, that is, the pressure in the gas pillow area is maintained within a certain range, and the liquid hydrogen can flow out normally by relying on the pressure difference between the gas pillow area, the gravity of the liquid hydrogen itself and the pressure at the hydrogen supply end. After the liquid hydrogen flows out, it needs to be converted from a liquid state to a gaseous state, and then supplied to a fuel cell engine after pressure regulation.

[0003] In related technologies, for example, Chinese Patent CN217235278U discloses a non-contact heat transfer pressurization vehicle-mounted gas supply system and vehicle. Part of the hydrogen gas heated and vaporized by the vaporizer is introduced into the pressurization circuit, and part of the pipeline in the pressurization circuit is arranged in the liquid hydrogen cylinder. The hot hydrogen gas flowing through the pressurization circuit can heat the liquid hydrogen and gaseous hydrogen in the liquid hydrogen cylinder, so that the liquid hydrogen in the liquid hydrogen cylinder evaporates into a gaseous phase, the pressure in the gas pillow area reaches the target value, and the supply of liquid hydrogen in the main circuit is realized. The hydrogen gas in the pressurization circuit will then be combined with the hydrogen gas in the main pipeline and then pass through the buffer tank to supply the fuel cell. However, in the above-mentioned prior art, the hydrogen gas used for heat exchange of the liquid hydrogen cylinder comes from the split hydrogen gas heated by the water bath vaporizer, and the initial temperature of this part of hydrogen gas for heat exchange depends on the excess heat of the fuel cell cooling water in the water bath vaporizer. This part of heat is not very stable, and a large amount of heat needs to be absorbed for liquid hydrogen vaporization. This may result in a slow liquid hydrogen vaporization rate and difficulty in quickly achieving self-pressurization, which may affect the stable supply of the main circuit. Therefore, there is an urgent need for a new type of fuel cell system and self-pressurization method that can quickly increase the pressure in the gas pillow area inside the liquid hydrogen cylinder while ensuring the stable supply of liquid hydrogen in the main circuit. SUMMARY

[0004] Therefore, the present application provides a fuel cell system and a pressurization method that can quickly increase the pressure in the gas pillow area inside the liquid hydrogen cylinder while ensuring the efficiency of heat exchange of the liquid hydrogen in the liquid hydrogen cylinder, so that the liquid hydrogen in the main circuit can be stably supplied.

[0005] In a first aspect, the embodiments of the present application provide a fuel cell system, comprising: a fuel cell stack; hydrogen inlet pipe, provided at an anode outlet of the stack, wherein a liquid hydrogen bottle is arranged on the hydrogen inlet pipe, and a first heat exchanger is arranged in the liquid hydrogen bottle; a gas-liquid separator, provided at an anode outlet of the stack; a self-pressurization pipe, connected to a gas outlet of the gas-liquid separator, and connected to the hydrogen inlet pipe through the first heat exchanger; a pressure detection assembly, arranged in the liquid hydrogen bottle, for monitoring pressure in a gas pillow area in the liquid hydrogen bottle; a control assembly, electrically connected to the pressure detection assembly, for controlling opening or closing of the self-pressurization pipe.

[0006] By using the above technical solution, when the pressure in the gas pillow area in the liquid hydrogen bottle is low, the unreacted hydrogen gas at the anode outlet of the stack can be re-injected into the liquid hydrogen bottle, and the heat of the hydrogen gas and the liquid hydrogen in the liquid hydrogen bottle are used for heat exchange, so as to increase the pressure in the gas pillow area in the liquid hydrogen bottle, thereby quickly increasing the internal pressure of the liquid hydrogen bottle and maintaining the stability of the liquid hydrogen supply.

[0007] In combination with the first aspect, in an embodiment, the first heat exchanger is a coil heat exchanger, and the first heat exchanger is arranged in a liquid hydrogen area in the liquid hydrogen bottle.

[0008] By using the above technical solution, the contact area of the unreacted hydrogen gas at the anode outlet of the stack with the liquid hydrogen after entering the liquid hydrogen bottle is increased, thereby increasing the heat exchange efficiency.

[0009] In combination with the first aspect, in an embodiment, a control valve is further arranged on the self-pressurization pipe, and the control assembly controls opening or closing of the self-pressurization pipe through the control valve.

[0010] By using the above technical solution, the opening and closing of the self-pressurization pipe are controlled.

[0011] In combination with the first aspect, in an embodiment, a pressurization valve is further arranged on the self-pressurization pipe, and the pressurization valve is located between the first heat exchanger and the control valve.

[0012] By using the above technical solution, the hydrogen pressure in the self-pressurization pipe 6 can be increased.

[0013] In combination with the first aspect, in an embodiment, the pressure detection assembly includes a first pressure sensor, and the first pressure sensor is arranged in the gas pillow area in the liquid hydrogen bottle.

[0014] By using the above technical solution, the pressure in the gas pillow area in the liquid hydrogen bottle is monitored, and normal operation of the self-pressurization is ensured.

[0015] In combination with the first aspect, in an implementation, the anode outlet of the stack is provided with a hydrogen discharge pipeline, and the hydrogen discharge pipeline is connected with the liquid outlet of the gas-liquid separator.

[0016] By using the above technical solution, the water at the anode outlet of the stack is discharged.

[0017] In combination with the first aspect, in an implementation, the gas outlet of the gas-liquid separator is provided with a hydrogen return pipeline, the other end of the hydrogen return pipeline is connected with the hydrogen inlet pipeline, a gas pump is further arranged on the hydrogen return pipeline, the self-pressurizing pipeline is connected with the hydrogen return pipeline and the connection point is located at the output end of the gas pump, and the self-pressurizing pipeline is connected with the gas outlet of the gas-liquid separator through the hydrogen return pipeline.

[0018] By using the above technical solution, the hydrogen gas that does not fully participate in the reaction at the anode of the stack is recycled to the hydrogen inlet pipeline to enter the stack again for reaction, thereby improving the utilization rate of hydrogen gas.

[0019] In combination with the first aspect, in an implementation, a buffer tank is further arranged on the hydrogen inlet pipeline, the buffer tank is located between the liquid hydrogen bottle and the anode inlet of the stack, a first pressure relief pipeline connected with the buffer tank is arranged on the liquid hydrogen bottle, and a second pressure relief pipeline is further arranged on the buffer tank.

[0020] By using the above technical solution, the pressure of the entire buffer tank and the liquid hydrogen bottle is maintained stable.

[0021] In combination with the first aspect, in an implementation, a second pressure sensor is further arranged in the buffer tank.

[0022] By using the above technical solution, the hydrogen pressure in the buffer tank is detected.

[0023] In combination with the first aspect, in an implementation, an adjusting assembly is further arranged on the hydrogen inlet pipeline, the adjusting assembly comprises a pressure reducing valve, a second heat exchanger and a proportional valve, the pressure reducing valve, the second heat exchanger and the proportional valve are arranged in sequence between the buffer tank and the anode inlet of the stack, the connection point of the self-pressurizing pipeline and the hydrogen inlet pipeline is located between the pressure reducing valve and the second heat exchanger, and the second heat exchanger is connected with the cooling liquid heat exchange pipeline of the stack.

[0024] By using the above technical solution, the pressure, temperature and flow of the hydrogen gas on the hydrogen inlet pipeline and the temperature and flow of the heat-exchanged hydrogen gas in the self-pressurizing pipeline are adjusted, so that the hydrogen gas required at the anode inlet of the stack can be met.

[0025] In combination with the first aspect, in an implementation, a third heat exchanger is further arranged on the hydrogen inlet pipeline, and the third heat exchanger is located between the buffer tank and the liquid hydrogen bottle.

[0026] By adopting the technical scheme, the vaporization heating of the liquid hydrogen is realized.

[0027] With reference to the first aspect, in an implementation, the method further comprises: The oxygen inlet pipeline is arranged at the cathode inlet of the stack, and the air compressor is arranged on the oxygen inlet pipeline. The oxygen outlet pipeline is arranged at the cathode outlet of the stack. The oxygen inlet pipeline and the oxygen outlet pipeline are connected with the third heat exchanger, the oxygen outlet pipeline is further connected with the hydrogen outlet pipeline, and the connection point of the oxygen outlet pipeline and the hydrogen outlet pipeline is located in front of the input end of the third heat exchanger.

[0028] By adopting the technical scheme, the vaporization efficiency of the liquid hydrogen in the hydrogen inlet pipeline can be effectively improved by using the double heat exchange of the air and the tail gas.

[0029] With reference to the first aspect, in an implementation, the air compressor is arranged at the output end or the input end of the third heat exchanger.

[0030] By adopting the technical scheme, the heat of the air entering the oxygen inlet pipeline can be effectively utilized.

[0031] The second aspect provides a pressurization method of a fuel cell system, which comprises the following steps: The pressure data of the air pillow area in the liquid hydrogen bottle is monitored by the pressure detection assembly; When the monitored pressure data is lower than the first pressure threshold, the control assembly controls the self-pressurization pipeline to be opened; The hydrogen separated by the gas-liquid separator is introduced into the inside of the first heat exchanger through the self-pressurization pipeline and exchanges heat with the liquid hydrogen in the liquid hydrogen bottle, so as to increase the pressure of the air pillow area in the liquid hydrogen bottle, and the hydrogen after heat exchange is returned to the hydrogen inlet pipeline through the self-pressurization pipeline and enters the stack again to react; When the pressure data of the air pillow area in the liquid hydrogen bottle monitored by the pressure detection assembly is higher than the first pressure threshold and lower than the second pressure threshold, the control assembly controls the self-pressurization pipeline to be closed.

[0032] With reference to the second aspect, in an implementation, the first pressure threshold is the minimum pressure value required to ensure that the liquid hydrogen can stably flow out of the liquid hydrogen bottle, and the second pressure threshold is the safe pressure value that can be borne by the air pillow area in the liquid hydrogen bottle.

[0033] The third aspect provides a vehicle with the fuel cell system as described in the above implementations.

[0034] The technical scheme provided by the embodiments of the present application has the following beneficial effects: 1. The fuel cell system, self-pressurization method and vehicle, when the pressure in the air pillow area of the liquid hydrogen tank is low, the unreacted hydrogen gas at the anode outlet of the stack is introduced into the first heat exchanger in the liquid hydrogen tank through the control assembly, and the heat of the hydrogen gas and the liquid hydrogen in the liquid hydrogen tank are used for heat exchange, so that the pressure in the air pillow area of the liquid hydrogen tank is self-pressurized, the initial temperature of the hydrogen gas is close to the maximum temperature of the stack during operation, and there is a significant temperature difference between the ultra-low temperature liquid hydrogen, so that the heat transfer efficiency is greatly improved during heat exchange, thereby not only improving the vaporization rate of the liquid hydrogen in the liquid hydrogen tank and ensuring the efficiency of the pressure increase in the air pillow area, but also avoiding the interruption of the liquid hydrogen supply caused by pressure fluctuations and ensuring the stable outflow of the liquid hydrogen.

[0035] 2. The fuel cell system, self-pressurization method and vehicle, the pressurized hydrogen gas is returned to the hydrogen inlet pipeline through the self-pressurization pipeline, mixed with the main hydrogen gas and reenters the anode of the stack to participate in the reaction, so that the unreacted hydrogen gas that may be discharged is reused, thereby greatly improving the utilization rate of the unreacted hydrogen gas at the anode outlet of the stack.

[0036] 3. The fuel cell system, self-pressurization method and vehicle, the third heat exchanger is provided, the temperature of the air entering the oxygen inlet pipeline and the heat of the tail gas discharged from the stack are used for heat exchange with the liquid hydrogen entering the hydrogen inlet pipeline, so that the liquid hydrogen can be fully vaporized, and the temperature of the air in the oxygen inlet pipeline is reduced after heat exchange with the liquid hydrogen, thereby reducing the energy consumption of the subsequent air compressor and cooling device.

[0037] 4. The fuel cell system, self-pressurization method and vehicle, the second heat exchanger is provided, the temperature of the stack cooling liquid is used for heat exchange with the residual liquid hydrogen in the hydrogen inlet pipeline and the gas hydrogen returned from the self-pressurization pipeline, the residual liquid hydrogen in the hydrogen inlet pipeline is further eliminated, the temperature of the gas hydrogen returned from the self-pressurization pipeline is increased, so that it can be maintained within the appropriate hydrogen temperature range required by the stack, and the impact of low-temperature hydrogen on the reaction efficiency of the stack is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating labor.

[0039] Figure 1 The figure is a schematic diagram of the fuel cell system of the present application; Figure 2 The figure is a schematic diagram of the second embodiment of the present application; Figure 3This is a schematic diagram showing the connection of the back pressure valve, intercooler, hydrogen discharge and drainage valve, air filter, and other devices in Embodiment 1 of the present invention.

[0040] In the picture: 1. Fuel cell stack; 2. Hydrogen inlet pipeline; 3. Oxygen inlet pipeline; 4. Oxygen venting pipeline; 5. Hydrogen venting pipeline; 6. Self-pressurization pipeline; 7. Hydrogen return pipeline; 8. Liquid hydrogen cylinder; 9. First heat exchanger; 10. Third heat exchanger; 11. Buffer tank; 12. Pressure reducing valve; 13. Second heat exchanger; 14. Proportional valve; 15. Control valve; 16. Pressure boosting valve; 17. First pressure relief pipeline; 18. First pressure sensor; 19. Second pressure sensor; 20. Second pressure relief pipeline; 21. Air compressor; 22. Gas-liquid separator; 23. Air pump; 24. Intercooler; 25. Humidifier; 26. Back pressure valve; 27. Hydrogen venting and draining valve; 28. Air filter; 29. ​​Hydrogen processing unit. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0042] This application provides a fuel cell system, a self-pressurization method, and a vehicle. Unreacted hydrogen from the anode outlet of the fuel cell stack can be reintroduced into a first heat exchanger inside a liquid hydrogen tank. The heat from this portion of hydrogen is used to exchange heat with the liquid hydrogen inside the tank, thereby achieving self-pressurization of the pressure in the gas pillow area of ​​the liquid hydrogen tank. This greatly enhances the heat transfer efficiency, not only improving the vaporization rate of liquid hydrogen inside the tank and ensuring the efficiency of the pressure increase in the gas pillow area, but also avoiding interruptions in the liquid hydrogen supply caused by pressure fluctuations, ensuring a stable outflow of liquid hydrogen.

[0043] Specifically, Example 1: like Figure 1 As shown, Embodiment 1 of this application provides a fuel cell system, including: Fuel cell 1, as the core of the system, is responsible for converting the chemical energy of hydrogen and oxygen into electrical energy through electrochemical reactions. Hydrogen inlet line 2 is responsible for supplying gaseous hydrogen to the anode inlet of fuel cell stack 1. It is located at the anode inlet of fuel cell stack 1, while gaseous hydrogen is supplied through liquid hydrogen bottle 8, which is located on hydrogen inlet line 2. Specifically, the liquid hydrogen cylinder 8 is used to store liquid hydrogen and provide hydrogen for the chemical reaction of the fuel cell stack 1. Liquid hydrogen and gaseous hydrogen exist inside at the same time, and the pressure of the gaseous hydrogen needs to be maintained within a stable range to ensure a stable supply of liquid hydrogen. The liquid hydrogen cylinder 8 is also equipped with a first heat exchanger 9, which is located in the liquid hydrogen zone inside the liquid hydrogen cylinder 8. Specifically, the first heat exchanger 9 is a coil heat exchanger. The coil heat exchanger has a larger contact area with the liquid hydrogen in the liquid hydrogen tank 8, which can effectively increase the heat exchange area between the gaseous hydrogen and liquid hydrogen entering the first heat exchanger 9, thereby improving the heat exchange efficiency and ensuring the rate of liquid hydrogen vaporization in the liquid hydrogen tank 8 and the efficiency of the pressure increase in the gas pillow area.

[0044] Gas-liquid separator 22 is used to separate the unreacted hydrogen gas discharged from the anode outlet of fuel cell stack 1 from the water generated by the reaction. This unreacted hydrogen gas has high heat and can be reused; and gas-liquid separator 22 is located at the anode outlet of fuel cell stack 1. In addition, the gas outlet of the gas-liquid separator 22 is also equipped with a hydrogen return line 7. The other end of the hydrogen return line 7 is connected to the hydrogen inlet line 2. The hydrogen return line 7 is also equipped with a gas pump 23. The self-pressurization line 6 is connected to the hydrogen return line 7 and the connection point is located at the output end of the gas pump 23. The self-pressurization line 6 is connected to the gas outlet of the gas-liquid separator 22 through the hydrogen return line 7. Specifically, the gas-liquid separator 22 separates the incompletely reacted hydrogen gas discharged from the anode outlet of the fuel cell stack 1 from the water generated by the reaction. The water generated by the reaction is discharged normally, while the incompletely reacted hydrogen gas is reintroduced into the hydrogen inlet pipe 2 through the hydrogen return pipe 7, thereby realizing the recycling of this part of the hydrogen gas and improving the utilization rate of hydrogen gas.

[0045] Hydrogen discharge line 5 is connected to the liquid outlet of gas-liquid separator 22; As mentioned above, hydrogen discharge pipeline 5 is used to discharge hydrogen gas that did not fully participate in the reaction and water generated by the reaction at the anode of fuel cell stack 1; In addition, such as Figure 3 As shown, the hydrogen discharge pipeline 5 is also equipped with a hydrogen discharge valve 27, which is used to discharge the liquid water separated from the liquid output port of the gas-liquid separator 22 to prevent liquid water from accumulating in the hydrogen discharge pipeline 5 and the gas-liquid separator 22.

[0046] The self-pressurizing pipeline 6 is connected to the gas outlet of the gas-liquid separator 22, and the self-pressurizing pipeline 6 is also connected to the hydrogen inlet pipeline 2 through the first heat exchanger 9. The one end of the self-pressurizing pipeline 6 is connected to the hydrogen inlet pipeline 2 through the first heat exchanger 9, and the other end is connected to the gas outlet of the gas-liquid separator 22 through the hydrogen return pipeline 7, so that the hydrogen gas in the hydrogen return pipeline 7 can enter the first heat exchanger 9 through the self-pressurizing pipeline 6 to exchange heat with the hydrogen gas in the liquid hydrogen bottle 8; Specifically, when the pressure in the air pillow area of the liquid hydrogen bottle 8 is insufficient, the self-pressurizing pipeline 6 can introduce the hydrogen gas that is not completely reacted in the hydrogen return pipeline 7 into the first heat exchanger 9 in the liquid hydrogen bottle 8, and exchange heat with the liquid hydrogen in the liquid hydrogen bottle 8 by using the heat of the hydrogen gas, so as to realize the self-pressurization of the air pillow area in the liquid hydrogen bottle 8. The initial temperature of the hydrogen gas is close to the highest temperature of the electric pile 1 during operation, and there is a significant temperature difference between the hydrogen gas and the ultra-low temperature liquid hydrogen, so the heat transfer efficiency is greatly improved during heat exchange. Therefore, not only the vaporization rate of the liquid hydrogen in the liquid hydrogen bottle 8 is improved, but also the efficiency of increasing the pressure in the air pillow area is ensured.

[0047] The hydrogen gas after heat exchange with the liquid hydrogen in the liquid hydrogen bottle 8 can return to the hydrogen inlet pipeline 2 through the self-pressurizing pipeline 6, so as to realize the recycling of the self-pressurized hydrogen gas, and further improve the utilization efficiency of the hydrogen gas in the system.

[0048] In addition, when the self-pressurizing pipeline 6 is not opened, the hydrogen gas that is not completely reacted and the water generated by the reaction are separated by the gas-liquid separator 22 after being discharged from the anode outlet of the electric pile 1. The hydrogen gas that is not completely reacted enters the hydrogen return pipeline 7 through the gas outlet of the gas-liquid separator 22, and the hydrogen gas can be introduced into the hydrogen inlet pipeline 2 by using the gas pump 23 as a power source, so as to realize the recycling of the hydrogen gas that is not completely reacted.

[0049] A pressure detection assembly is arranged in the air pillow area of the liquid hydrogen bottle 8, and is used for monitoring the pressure in the air pillow area of the liquid hydrogen bottle 8; In the embodiment, the pressure detection assembly includes a first pressure sensor 18, and the first pressure sensor 18 is arranged in the air pillow area of the liquid hydrogen bottle 8. The pressure data in the air pillow area of the liquid hydrogen bottle 8 is monitored by the first pressure sensor 18. Specifically, when the monitored pressure data is greater than the minimum pressure in the air pillow area of the liquid hydrogen bottle 8, the self-pressurizing pipeline 6 is not opened. When the pressure data monitored by the first pressure sensor 18 is less than the minimum pressure in the air pillow area of the liquid hydrogen bottle 8, the self-pressurizing pipeline 6 is opened to introduce the hydrogen gas that is not completely reacted in the hydrogen return pipeline 7 into the first heat exchanger 9 in the liquid hydrogen bottle 8, and exchange heat with the liquid hydrogen in the liquid hydrogen bottle 8 by using the heat of the hydrogen gas, so as to realize the self-pressurization of the air pillow area in the liquid hydrogen bottle 8. The hydrogen gas after heat exchange can return to the hydrogen inlet pipeline 2 through the self-pressurizing pipeline 6 to participate in the reaction, and the process is repeated until the pressure data monitored by the first pressure sensor 18 is greater than the minimum pressure in the air pillow area of the liquid hydrogen bottle 8, so as to realize the control of the self-pressurization of the liquid hydrogen bottle 8.

[0050] a control component electrically connected with the pressure detection component, for controlling opening or closing of the self-pressurization pipeline 6; The control component can be a vehicle control system (VCU), a fuel cell control system (FCCU), or any other PLC controller capable of receiving pressure signals and outputting control instructions. In this embodiment, the control component is preferably a vehicle control system, which realizes self-pressurization of the air pillow area in the liquid hydrogen tank 8. Specifically, a first pressure threshold is set based on the vehicle control system, which is the minimum pressure value required to ensure stable outflow of liquid hydrogen from the liquid hydrogen tank 8. When the pressure in the air pillow area of the liquid hydrogen tank 8 is lower than the first pressure threshold, the vehicle control system controls the self-pressurization pipeline 6 to open, so that the hydrogen in the hydrogen return pipeline 7 is introduced into the first heat exchanger 9 in the liquid hydrogen tank 8 under the action of the air pump 23, and heat exchange is performed between the hydrogen and the liquid hydrogen in the liquid hydrogen tank 8, thereby realizing self-pressurization of the air pillow area in the liquid hydrogen tank 8. When the first pressure sensor 18 detects that the pressure in the air pillow area of the liquid hydrogen tank 8 is higher than the first pressure threshold, the vehicle control unit controls the self-pressurization pipeline 6 to close, so that the pressure in the air pillow area of the liquid hydrogen tank 8 can always be maintained within a stable range, ensuring stable outflow of liquid hydrogen and avoiding interruption of liquid hydrogen supply caused by pressure fluctuations.

[0051] In this embodiment, the self-pressurization pipeline 6 is also provided with a control valve 15, and the control component controls opening or closing of the self-pressurization pipeline 6 through the control valve 15. The self-pressurization pipeline 6 is also provided with a pressurization valve 16, which is located between the first heat exchanger 9 and the control valve 15.

[0052] The control valve 15 is electrically connected with the vehicle control system and is used to control opening and closing of the self-pressurization pipeline 6. When the control valve 15 is opened, the hydrogen that does not fully participate in the reaction at the anode of the fuel cell stack 1 will enter the self-pressurization pipeline 6 under the guidance of the air pump 23, thereby realizing self-pressurization of the liquid hydrogen tank 8. Specifically, when the pressure in the air pillow area of the liquid hydrogen tank 8 is lower than the first pressure threshold, the vehicle control system controls the control valve 15 to open, thereby realizing opening of the self-pressurization pipeline 6. When the pressure in the air pillow area of the liquid hydrogen tank 8 is higher than the first pressure threshold and lower than a second pressure threshold, the vehicle control system controls the control valve 15 to close, thereby realizing closing of the self-pressurization pipeline 6.

[0053] In addition, the pressurization valve 16 is used to actively increase the pressure of the hydrogen entering the liquid hydrogen tank 8 for heat exchange in the self-pressurization pipeline 6, thereby significantly improving the efficiency and speed of the self-pressurization process.

[0054] In this embodiment, the hydrogen inlet pipeline 2 is also provided with a buffer tank 11, which is located between the liquid hydrogen bottle 8 and the anode inlet of the stack 1. The liquid hydrogen bottle 8 is provided with a first pressure relief pipeline 17 connected to the buffer tank 11. The buffer tank 11 is also provided with a second pressure relief pipeline 20.

[0055] The buffer tank 11 is used to balance the pressure fluctuation of the high-pressure hydrogen gas after the vaporization of the liquid hydrogen in the hydrogen inlet pipeline 2, so as to ensure the stable hydrogen pressure supplied to the stack 1. The buffer tank 11 is also provided with a second pressure sensor 19 for monitoring the pressure in the buffer tank 11. In addition, based on the setting of the first pressure threshold, the embodiment is also provided with a second pressure threshold, which is the safe pressure value, i.e. the maximum pressure value, that the air pillow area in the liquid hydrogen bottle 8 can withstand. Specifically, the first pressure relief pipeline 17 and the second pressure relief pipeline 20 are each provided with a safety valve. When the first pressure sensor 18 monitors that the pressure in the air pillow area of the liquid hydrogen bottle 8 exceeds the second pressure threshold, the vehicle control unit will control the safety valve on the first pressure relief pipeline 17 to open. At this time, the hydrogen in the air pillow area of the liquid hydrogen bottle 8 will enter the buffer tank 11 through the first pressure relief pipeline 17, so as to maintain the stable pressure in the air pillow area of the liquid hydrogen bottle 8. At the same time, the high-pressure hydrogen gas can also be recovered to the buffer tank 11, so as to avoid waste. When the first pressure sensor 18 monitors that the pressure in the air pillow area of the liquid hydrogen bottle 8 is lower than the second pressure threshold and higher than the first pressure threshold, the vehicle control unit will control the safety valve on the first pressure relief pipeline 17 to close. At this time, the self-pressurizing pipeline 6 is in a closed state. When the first pressure sensor 18 monitors that the pressure in the air pillow area of the liquid hydrogen bottle 8 is lower than the first pressure threshold, the vehicle control unit will open the self-pressurizing pipeline 6 for self-pressurization until the pressure in the air pillow area of the liquid hydrogen bottle 8 is between the first pressure threshold and the second pressure threshold.

[0056] In addition, if the second pressure sensor 19 monitors that the pressure in the buffer tank 11 exceeds the maximum pressure that the buffer tank 11 can withstand, the vehicle control system will control the safety valve on the second pressure relief pipeline 20 to open, so as to discharge the hydrogen through the second pressure relief pipeline 20 until the second pressure sensor 19 detects that the pressure in the buffer tank 11 is lower than the maximum pressure that it can withstand, so as to maintain the stable pressure in the buffer tank 11. If the second pressure sensor 19 monitors that the pressure in the buffer tank 11 exceeds the hydrogen supply pressure required by the stack 1 but does not exceed the maximum pressure that the buffer tank 11 can withstand, the vehicle control unit will temporarily close the liquid hydrogen bottle 8, and preferentially use this part of the hydrogen to replace the hydrogen required for the reaction of the stack 1. In this way, the loss of this part of the hydrogen can be reduced, and the utilization rate of the hydrogen in the system is further improved.

[0057] It should be noted here that, as mentioned above, Figure 3As shown, the hydrogen treatment device 29 is arranged on the second pressure relief pipeline 20, which is preferably a purifier, and is used to filter and purify the hydrogen discharged from the second pressure relief pipeline 20 to avoid environmental pollution and safety hazards caused by direct discharge.

[0058] In this embodiment, the hydrogen inlet pipeline 2 is further provided with an adjusting assembly, which includes a pressure reducing valve 12, a second heat exchanger 13 and a proportional valve 14. The pressure reducing valve 12, the second heat exchanger 13 and the proportional valve 14 are arranged in sequence between the buffer tank 11 and the anode inlet of the stack 1. The connection point of the self-pressurizing pipeline 6 and the hydrogen inlet pipeline 2 is located between the pressure reducing valve 12 and the second heat exchanger 13. The second heat exchanger 13 is connected with the cooling liquid heat exchange pipeline of the stack 1.

[0059] The adjusting assembly is arranged to adjust the temperature, pressure and flow of the hydrogen in the hydrogen inlet pipeline 2 and the temperature and flow of the hydrogen in the self-pressurizing pipeline 6 after heat exchange, so that the two parts of hydrogen can reach the required hydrogen temperature, flow and pressure range of the anode inlet of the stack 1, avoiding the impact of unstable hydrogen on the reaction efficiency of the stack 1.

[0060] The pressure reducing valve 12 is used to reduce the high-pressure hydrogen output by the buffer tank 11 to the working pressure required by the stack 1. The proportional valve 14 is used to adjust the hydrogen supply flow into the stack 1, thereby ensuring the stability of the hydrogen flow and pressure into the stack 1.

[0061] In addition, the second heat exchanger 13 can exchange heat between the temperature of the cooling liquid of the stack 1 and the residual liquid hydrogen in the hydrogen inlet pipeline 2 and the gas hydrogen backflowing from the self-pressurizing pipeline 6. On the one hand, it can further eliminate the residual liquid hydrogen in the hydrogen inlet pipeline 2. On the other hand, it can also increase the temperature of the backflowing gas hydrogen from the self-pressurizing pipeline 6, so that it can be maintained within the suitable hydrogen temperature range required by the stack 1, avoiding the impact of low-temperature hydrogen on the reaction efficiency of the stack 1.

[0062] Therefore, the hydrogen pressurized in the air pillow area of the liquid hydrogen bottle 8 through the self-pressurizing pipeline 6 will be backflowed to the hydrogen inlet pipeline 2 through the self-pressurizing pipeline 6. This part of hydrogen will be mixed with the hydrogen in the hydrogen inlet pipeline 2 and then re-enter the anode of the stack 1 to participate in the reaction. The hydrogen after heat exchange in the self-pressurizing pipeline 6 not only does not affect the hydrogen supply process in the hydrogen inlet pipeline 2, but also can be re-injected into the stack 1 to participate in the reaction again in the most suitable temperature and flow state under the adjustment of the second heat exchanger 13 and the proportional valve 14 after heat exchange, greatly improving the utilization rate of the hydrogen not participating in the reaction at the anode outlet of the stack 1.

[0063] It is noted here that the cooling liquid heat exchange pipeline of the stack 1 refers to the pipeline for the flow of the cooling liquid for cooling the stack 1, and a large amount of heat is generated during the operation of the stack 1, and the circulation of the cooling liquid is required to maintain the stability of the temperature of the stack 1, so the temperature of the cooling liquid is used to realize the adjustment of the hydrogen temperature on the final hydrogen inlet pipeline 2, so that it can be more suitable for the hydrogen temperature required by the anode inlet of the stack 1.

[0064] In this embodiment, the hydrogen inlet pipeline 2 is also provided with a third heat exchanger 10, and the third heat exchanger 10 is located between the buffer tank 11 and the liquid hydrogen bottle 8. The third heat exchanger 10 is used for heat exchange between the liquid hydrogen on the hydrogen inlet pipeline 2 and the air entering the stack 1 and the water discharged from the anode outlet of the stack 1, so as to realize the primary heating of the liquid hydrogen on the hydrogen inlet pipeline 2. This part of heat can make the liquid hydrogen fully vaporize, on the one hand, improve the utilization rate of the heat of the water discharged from the anode outlet of the stack 1 and the heat of the air entering the stack 1, and on the other hand, ensure the vaporization quality of the liquid hydrogen before entering the stack 1.

[0065] Through the double heating of the liquid hydrogen on the hydrogen inlet pipeline 2 by the second heat exchanger 13 and the third heat exchanger 10, the waste heat of the stack 1, the air temperature and the cooling liquid waste heat are fully utilized, the energy is used in a step-by-step and efficient manner, the vaporization effect of the liquid hydrogen on the hydrogen inlet pipeline 2 is ensured, and the waste of this part of heat is avoided.

[0066] In this embodiment, it also includes: The oxygen inlet pipeline 3 is arranged at the cathode inlet of the stack 1, and the air compressor 21 is arranged on the oxygen inlet pipeline 3. The oxygen inlet pipeline 3 refers to the pipeline of the air entering the cathode inlet of the stack 1 to participate in the reaction, as shown in the figure, and the intercooler 24, the humidifier 25 and the air filter 28 and other components are arranged on the pipeline, which are used to process the ambient air to meet the temperature, pressure, humidity and cleanliness required by the reaction of the stack 1. Figure 3

[0067] The air filter 28 is located at the inlet of the oxygen inlet pipeline 3, the intercooler 24 is located at the output end of the air compressor 21, and the humidifier 25 is located between the intercooler 24 and the cathode inlet of the stack 1. The air filter 28 is used to filter out the dust and impurities and other particles in the air entering the oxygen inlet pipeline 3, so as to ensure the quality of the air entering the stack 1 to participate in the reaction; The intercooler 24 is used to reduce the temperature of the air compressed by the air compressor 21, so as to ensure that the air on the oxygen inlet pipeline 3 is in a suitable temperature range when entering the stack 1; The humidifier 25 is used to increase the humidity of the air compressed by the air compressor 21, so as to ensure that the proton exchange membrane in the stack 1 can be kept wet, thereby ensuring the efficient and stable operation of the fuel cell; ​An oxygen exhaust pipeline 4 is arranged at the cathode outlet of the stack 1 and is used to exhaust the exhaust gas at the cathode of the stack 1. The oxygen inlet pipeline 3 and the oxygen exhaust pipeline 4 are connected with the third heat exchanger 10, and the oxygen exhaust pipeline 4 is also connected with the hydrogen exhaust pipeline 5. The connection point of the oxygen exhaust pipeline 4 and the hydrogen exhaust pipeline 5 is located in front of the input end of the third heat exchanger 10.

[0068] In addition, as shown in the figure, a back pressure valve 26 is arranged on the oxygen exhaust pipeline 4, which is used to control the exhaust back pressure of the oxygen exhaust pipeline 4 and maintain the pressure stability at the cathode side of the stack 1, so as to ensure the high efficiency and safe operation of the fuel cell system under the optimal working condition. Figure 3 In this embodiment, the oxygen exhaust pipeline 4 and the hydrogen exhaust pipeline 5 are combined together in front of the input end of the third heat exchanger 10, so that the heat of the exhaust gas and water in the oxygen exhaust pipeline 4 and the hydrogen exhaust pipeline 5 can be fully utilized, thereby greatly improving the vaporization efficiency of the liquid hydrogen at the outlet of the liquid hydrogen bottle 8. Figure 3 In addition, as shown in the figure, the oxygen exhaust pipeline 4 is also connected with a humidifier 25, so that the high-temperature and high-humidity exhaust gas exhausted from the cathode outlet of the stack 1 can be introduced into the humidifier 25 as a wet source, and the moisture and heat thereof can be used to humidify and preheat the compressed air entering the humidifier 25, thereby realizing the efficient recycling of the water and heat in the system.

[0069] It should be noted that in this embodiment, the air compressor 21 is arranged at the output end of the third heat exchanger 10, that is, the air entering the oxygen inlet pipeline 3 is first exchanged by the third heat exchanger 10 and then pressurized by the air compressor 21.

[0070] Specifically, by arranging the third heat exchanger 10, the temperature of the air entering the oxygen inlet pipeline 3, the heat of the exhaust gas and water in the oxygen exhaust pipeline 4 and the hydrogen exhaust pipeline 5, and the liquid hydrogen entering the hydrogen inlet pipeline 2 are exchanged, so that the liquid hydrogen can be fully vaporized. After the vaporization of the liquid hydrogen by the third heat exchanger 10, the liquid hydrogen is further exchanged by the second heat exchanger 13, which can further eliminate the residual liquid hydrogen in the hydrogen inlet pipeline 2, and can also increase the temperature of the hydrogen backflow in the self-pressurization pipeline 6, so that the hydrogen can be maintained in the appropriate temperature range required by the stack 1, thereby avoiding the impact of low-temperature hydrogen on the stack 1 and affecting the reaction efficiency.

[0071] In addition, since the temperature of the air in the oxygen inlet pipeline 3 will be reduced after being exchanged with the liquid hydrogen in the hydrogen inlet pipeline 2, the energy consumption of the subsequent air compressor 21 and intercooler 24 can be reduced.

[0072] ​​In summary, in the first aspect of the embodiment, when the pressure in the air pillow area of the liquid hydrogen bottle 8 is low, the unreacted hydrogen gas at the anode outlet of the stack 1 can be introduced into the first heat exchanger 9 in the liquid hydrogen bottle 8 through the control assembly and the self-pressurizing pipeline 6, and the heat of the hydrogen gas and the liquid hydrogen in the liquid hydrogen bottle 8 are exchanged to realize self-pressurization of the air pillow area in the liquid hydrogen bottle 8. The initial temperature of the hydrogen gas is close to the highest temperature of the stack 1 during operation, and there is a significant temperature difference between the hydrogen gas and the liquid hydrogen, thereby greatly enhancing the heat transfer efficiency during heat exchange. Therefore, the vaporization rate of the liquid hydrogen in the liquid hydrogen bottle 8 is improved, and the efficiency of increasing the pressure in the air pillow area is ensured. In the second aspect of the embodiment, when the first pressure sensor 18 detects that the pressure in the air pillow area of the liquid hydrogen bottle 8 is lower than the first pressure threshold, in order to ensure that the liquid hydrogen can flow out of the liquid hydrogen bottle 8 stably, the control assembly controls the self-pressurizing pipeline 6 to open. At this time, the hydrogen gas in the hydrogen return pipeline 7 is introduced into the first heat exchanger 9 in the liquid hydrogen bottle 8 under the action of the air pump 23, and the heat of the hydrogen gas and the liquid hydrogen in the liquid hydrogen bottle 8 are exchanged to realize self-pressurization of the air pillow area in the liquid hydrogen bottle 8. When the first pressure sensor 18 detects that the pressure in the air pillow area of the liquid hydrogen bottle 8 is higher than the first pressure threshold, the control assembly controls the self-pressurizing pipeline 6 to close. Therefore, the pressure in the air pillow area of the liquid hydrogen bottle 8 can be maintained within a stable range, ensuring that the liquid hydrogen can flow out stably, and avoiding interruption of the supply of liquid hydrogen due to pressure fluctuations. In the third aspect of the embodiment, the pressurized hydrogen gas flows back to the hydrogen inlet pipeline 2 through the self-pressurizing pipeline 6, mixes with the hydrogen gas on the hydrogen inlet pipeline 2, and reenters the anode of the stack 1 to participate in the reaction. This process allows the unreacted hydrogen gas that would have been discharged to be reused, thereby greatly improving the utilization rate of the unreacted hydrogen gas at the anode outlet of the stack 1.

[0073] In the fourth aspect of the embodiment, the third heat exchanger 10 is provided, and the temperature of the air entering the oxygen inlet pipeline 3 and the heat of the exhaust gas discharged from the stack 1 are exchanged with the liquid hydrogen entering the hydrogen inlet pipeline 2, so that the liquid hydrogen can be fully vaporized. At the same time, the temperature of the air in the oxygen inlet pipeline 3 decreases after heat exchange with the liquid hydrogen, thereby reducing the energy consumption of the subsequent air compressor 21 and intercooler 24.

[0074] In the fifth aspect of the embodiment, the second heat exchanger 13 is provided, and the temperature of the cooling liquid of the stack 1 is exchanged with the residual liquid hydrogen in the hydrogen inlet pipeline 2 and the hydrogen gas flowing back through the self-pressurizing pipeline 6, further eliminating the residual liquid hydrogen in the hydrogen inlet pipeline 2, and increasing the temperature of the hydrogen gas flowing back through the self-pressurizing pipeline 6, so that it can be maintained within the appropriate temperature range of the hydrogen gas required by the stack 1, avoiding the impact of low-temperature hydrogen gas on the stack 1 and affecting the reaction efficiency.

[0075] Based on the same technical concept as embodiment one, the present application also provides embodiment two: The difference from embodiment one is that the air compressor 21 is located at the input end of the third heat exchanger 10, that is, the air entering the oxygen inlet pipeline 3 is first pressurized by the air compressor 21 and then passes through the third heat exchanger 10 to exchange heat with the liquid hydrogen in the hydrogen inlet pipeline 2. Specifically, as shown in Figure 2 The air entering the oxygen inlet pipeline 3 is first pressurized by the air compressor 21, and then the temperature rises, and then passes through the third heat exchanger 10 to exchange heat with the liquid hydrogen in the hydrogen inlet pipeline 2, thereby further improving the efficiency of the liquid hydrogen vaporization in the third heat exchanger 10.

[0076] Based on the same technical concept as embodiment one and embodiment two, the present application also provides embodiment three: The self-pressurization method based on the fuel cell system comprises the following steps: The pressure data of the air pillow area in the liquid hydrogen bottle 8 is monitored by the first pressure sensor 18; When the pressure data of the air pillow area in the liquid hydrogen bottle 8 monitored by the first pressure sensor 18 is lower than the first pressure threshold, the vehicle control system will control the self-pressurization pipeline 6 to open through the control valve 15; After the self-pressurization pipeline 6 is opened, the hydrogen gas in the hydrogen return pipeline 7 will be introduced into the first heat exchanger 9 in the liquid hydrogen bottle 8 under the action of the air pump 23, and heat exchange is carried out with the liquid hydrogen in the liquid hydrogen bottle 8 to realize self-pressurization of the air pillow area in the liquid hydrogen bottle 8, and the hydrogen gas after heat exchange with the liquid hydrogen in the liquid hydrogen bottle 8 will return to the hydrogen inlet pipeline 2 through the self-pressurization pipeline 6 and enter the stack 1 again for reaction; When the pressure data of the air pillow area in the liquid hydrogen bottle 8 monitored by the first pressure sensor 18 is higher than the first pressure threshold and lower than the second pressure threshold, the vehicle control system will control the self-pressurization pipeline 6 to close through the control valve 15.

[0077] The first pressure threshold is the minimum pressure value required to ensure that the liquid hydrogen can flow out of the liquid hydrogen bottle 8 stably, and the second pressure threshold is the safe pressure value that the air pillow area in the liquid hydrogen bottle 8 can withstand.

[0078] Specifically, the first pressure threshold is the basic guarantee for the normal operation of the liquid hydrogen bottle 8. As a cryogenic liquid fuel, the storage and flow of liquid hydrogen in the liquid hydrogen bottle 8 require precise pressure control. Because the flow of liquid hydrogen requires a certain pressure difference to overcome the pipe resistance and the opening pressure of the valve, if the pressure is insufficient, the liquid hydrogen cannot flow out at a stable flow rate, thereby affecting the stable hydrogen supply of the entire fuel cell system. When the pressure of the air pillow area in the liquid hydrogen bottle 8 is lower than the first pressure threshold, the flow of liquid hydrogen will be hindered, resulting in supply interruption, so the first pressure threshold is set to ensure the stable supply of liquid hydrogen in the liquid hydrogen bottle 8. The second pressure threshold is important for the safe operation of the liquid hydrogen tank 8. The interior of the liquid hydrogen tank 8 is usually divided into a liquid phase zone and a gas phase zone, which is also referred to as a gas pillow zone. The gas pillow zone provides a buffer space for gas when the liquid hydrogen evaporates or the liquid level changes, thereby preventing the pressure in the liquid hydrogen tank 8 from being too high and causing danger. When the pressure in the liquid hydrogen tank exceeds the second pressure threshold, the structural integrity of the liquid hydrogen tank 8 may be threatened, and even the liquid hydrogen tank 8 may be broken, thereby causing a serious safety accident. Therefore, the second pressure threshold is set to ensure that the pressure in the gas pillow zone of the liquid hydrogen tank 8 is stable.

[0079] Therefore, based on the above setting of the first pressure threshold and the second pressure threshold, the embodiment maintains the stability of the hydrogen pressure in the liquid hydrogen tank 8 through the cooperation of the self-pressurizing pipeline 6 and the first pressure relief pipeline 17, thereby ensuring the safety and stability of the entire fuel cell system. Specifically, when the first pressure sensor 18 detects that the pressure in the gas pillow zone of the liquid hydrogen tank 8 exceeds the second pressure threshold, the vehicle control unit controls the safety valve on the first pressure relief pipeline 17 to open. At this time, the hydrogen in the gas pillow zone of the liquid hydrogen tank 8 enters the buffer tank 11 through the first pressure relief pipeline 17, thereby maintaining the stability of the pressure in the gas pillow zone of the liquid hydrogen tank 8. Meanwhile, the high-pressure hydrogen can also be recovered to the buffer tank 11, thereby avoiding waste. When the first pressure sensor 18 detects that the pressure in the gas pillow zone of the liquid hydrogen tank 8 is lower than the second pressure threshold and higher than the first pressure threshold, the vehicle control unit controls the safety valve on the first pressure relief pipeline 17 to close. At this time, the self-pressurizing pipeline 6 is in a closed state. When the first pressure sensor 18 detects that the pressure in the gas pillow zone of the liquid hydrogen tank 8 is lower than the first pressure threshold, the vehicle control unit opens the self-pressurizing pipeline 6 for pressurization until the pressure in the gas pillow zone of the liquid hydrogen tank 8 is between the first pressure threshold and the second pressure threshold.

[0080] Embodiment Four The embodiment four of the present application provides a vehicle with a fuel cell system as described in the above embodiment one or embodiment two. Specifically, A vehicle provided with a fuel cell system, comprising: The fuel cell stack 1; The hydrogen inlet pipeline 2 is arranged at the anode inlet of the fuel cell stack 1. The liquid hydrogen tank 8 is arranged on the hydrogen inlet pipeline 2. The first heat exchanger 9 is arranged in the liquid hydrogen tank 8. The gas-liquid separator 22 is arranged at the anode outlet of the fuel cell stack 1. The self-pressurizing pipeline 6 is connected with the gas outlet of the gas-liquid separator 22. The self-pressurizing pipeline 6 is further connected with the hydrogen inlet pipeline 2 through the first heat exchanger 9. The pressure detection assembly is arranged in the gas pillow zone of the liquid hydrogen tank 8. The pressure detection assembly comprises the first pressure sensor 18. a control component electrically connected with the pressure detection component, for controlling opening or closing of the self-pressurizing pipeline 6.

[0081] Further comprising a control valve 15 arranged on the self-pressurizing pipeline 6, and the control component controls opening or closing of the self-pressurizing pipeline 6 through the control valve 15.

[0082] Further comprising a pressurizing valve 16 arranged on the self-pressurizing pipeline 6, and the pressurizing valve 16 is located between the first heat exchanger 9 and the control valve 15.

[0083] Further comprising a hydrogen discharge pipeline 5 arranged at the anode outlet of the stack 1, and the hydrogen discharge pipeline 5 is connected with the liquid output port of the gas-liquid separator 22.

[0084] Further comprising a hydrogen return pipeline 7 arranged at the gas output port of the gas-liquid separator 22, and the other end of the hydrogen return pipeline 7 is connected with the hydrogen inlet pipeline 2, and a gas pump 23 is further arranged on the hydrogen return pipeline 7, the self-pressurizing pipeline 6 is connected with the hydrogen return pipeline 7 at the output end of the gas pump 23, and the self-pressurizing pipeline 6 is connected with the gas output port of the gas-liquid separator 22 through the hydrogen return pipeline 7.

[0085] Further comprising a buffer tank 11 arranged on the hydrogen inlet pipeline 2, and a second pressure sensor 19 is further arranged in the buffer tank 11, and the buffer tank 11 is located between the liquid hydrogen bottle 8 and the anode inlet of the stack 1, and a first pressure relief pipeline 17 connected with the buffer tank 11 is arranged on the liquid hydrogen bottle 8, and a second pressure relief pipeline 20 is further arranged on the buffer tank 11.

[0086] Further comprising an adjusting component arranged on the hydrogen inlet pipeline 2, and the adjusting component comprises a pressure reducing valve 12, a second heat exchanger 13 and a proportional valve 14, which are arranged in sequence between the buffer tank 11 and the anode inlet of the stack 1, and the connection point of the self-pressurizing pipeline 6 with the hydrogen inlet pipeline 2 is located between the pressure reducing valve 12 and the second heat exchanger 13, and the second heat exchanger 13 is connected with the cooling liquid heat exchange pipeline of the stack 1.

[0087] Further comprising a third heat exchanger 10 arranged on the hydrogen inlet pipeline 2, and the third heat exchanger 10 is located between the buffer tank 11 and the liquid hydrogen bottle 8.

[0088] Further comprising: an oxygen inlet pipeline 3 arranged at the cathode inlet of the stack 1, and an air compressor 21 is arranged on the oxygen inlet pipeline 3, and the air compressor 21 is arranged at the output end or input end of the third heat exchanger 10; an oxygen discharge pipeline 4 arranged at the cathode outlet of the stack 1; the oxygen inlet pipeline 3 and the oxygen discharge pipeline 4 are both connected with the third heat exchanger 10, and the oxygen discharge pipeline 4 is further connected with the hydrogen discharge pipeline 5, and the connection point of the oxygen discharge pipeline 4 and the hydrogen discharge pipeline 5 is located before the input end of the third heat exchanger 10.

[0089] When the first pressure sensor 18 monitors that the pressure of the air pillow area in the liquid hydrogen bottle 8 exceeds the second pressure threshold value during the operation of the vehicle, the vehicle control unit controls the safety valve on the first pressure relief pipeline 17 to open, at this time, the high-pressure hydrogen in the air pillow area of the liquid hydrogen bottle 8 enters the buffer tank 11 through the first pressure relief pipeline 17, so as to maintain the pressure stability of the air pillow area in the liquid hydrogen bottle 8, and the high-pressure hydrogen can also be recovered to the buffer tank 11 to avoid waste; when the first pressure sensor 18 monitors that the pressure of the air pillow area in the liquid hydrogen bottle 8 is lower than the second pressure threshold value and higher than the first pressure threshold value, the vehicle control unit controls the safety valve on the first pressure relief pipeline 17 to close, at this time, the self-pressurizing pipeline 6 is in a closed state; when the first pressure sensor 18 monitors that the pressure of the air pillow area in the liquid hydrogen bottle 8 is lower than the first pressure threshold value, the vehicle control unit opens the self-pressurizing pipeline 6 for pressurization until the pressure of the air pillow area in the liquid hydrogen bottle 8 is between the first pressure threshold value and the second pressure threshold value, thereby ensuring the safety and stability of the entire fuel cell system.

[0090] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0091] It should be noted that in the present application, relational terms such as "first" and "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0092] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A fuel cell system, characterized in that, include: fuel cell stack (1); A hydrogen inlet pipeline (2) is provided at the anode inlet of the fuel cell stack (1). A liquid hydrogen cylinder (8) is provided on the hydrogen inlet pipeline (2), and a first heat exchanger (9) is provided inside the liquid hydrogen cylinder (8). A gas-liquid separator (22) is located at the anode outlet of the fuel cell stack (1); The self-pressurizing pipeline (6) is connected to the gas outlet of the gas-liquid separator (22), and the self-pressurizing pipeline (6) is also connected to the hydrogen inlet pipeline (2) through the first heat exchanger (9). A pressure detection component is installed inside the liquid hydrogen cylinder (8) to monitor the pressure in the gas pillow area inside the liquid hydrogen cylinder (8); A control component, which is electrically connected to the pressure detection component, is used to control the opening or closing of the self-pressurizing line (6).

2. The fuel cell system according to claim 1, characterized in that, The first heat exchanger (9) is a coil heat exchanger, and the first heat exchanger (9) is located in the liquid hydrogen zone inside the liquid hydrogen cylinder (8).

3. A fuel cell system according to claim 1, characterized in that, The self-pressurizing pipeline (6) is also equipped with a control valve (15), and the control component controls the opening or closing of the self-pressurizing pipeline (6) through the control valve (15).

4. A fuel cell system according to claim 3, characterized in that, The self-pressurizing pipeline (6) is also equipped with a pressurizing valve (16), which is located between the first heat exchanger (9) and the control valve (15).

5. A fuel cell system according to claim 1, characterized in that, The pressure detection component is a first pressure sensor (18), which is located in the gas pillow area inside the liquid hydrogen cylinder (8).

6. A fuel cell system according to claim 1, characterized in that, The anode outlet of the fuel cell stack (1) is provided with a hydrogen discharge pipeline (5), which is connected to the liquid outlet of the gas-liquid separator (22).

7. A fuel cell system according to claim 1, characterized in that, The gas outlet of the gas-liquid separator (22) is provided with a hydrogen return pipeline (7). The other end of the hydrogen return pipeline (7) is connected to the hydrogen inlet pipeline (2). The hydrogen return pipeline (7) is also provided with a gas pump (23). The self-pressurizing pipeline (6) is connected to the hydrogen return pipeline (7) and the connection point is located at the output end of the gas pump (23). The self-pressurizing pipeline (6) is connected to the gas outlet of the gas-liquid separator (22) through the hydrogen return pipeline (7).

8. A fuel cell system according to claim 1, characterized in that, The hydrogen inlet pipeline (2) is also provided with a buffer tank (11), which is located between the liquid hydrogen cylinder (8) and the anode inlet of the fuel cell stack (1). The liquid hydrogen cylinder (8) is provided with a first pressure relief pipeline (17) connected to the buffer tank (11), and the buffer tank (11) is also provided with a second pressure relief pipeline (20).

9. A fuel cell system according to claim 8, characterized in that, The buffer tank (11) is also equipped with a second pressure sensor (19).

10. A fuel cell system according to claim 8, characterized in that, The hydrogen inlet pipeline (2) is also equipped with a regulating component, which includes a pressure reducing valve (12), a second heat exchanger (13) and a proportional valve (14). The pressure reducing valve (12), the second heat exchanger (13) and the proportional valve (14) are sequentially arranged between the buffer tank (11) and the anode inlet of the fuel cell stack (1). The connection point between the self-pressurizing pipeline (6) and the hydrogen inlet pipeline (2) is located between the pressure reducing valve (12) and the second heat exchanger (13). The second heat exchanger (13) is connected to the coolant heat exchange pipeline of the fuel cell stack (1).

11. A fuel cell system according to claim 8, characterized in that, The hydrogen inlet pipeline (2) is also equipped with a third heat exchanger (10), which is located between the buffer tank (11) and the liquid hydrogen cylinder (8).

12. A fuel cell system according to claim 11, characterized in that, Also includes: An oxygen inlet pipeline (3) is installed at the cathode inlet of the fuel cell stack (1), and an air compressor (21) is installed on the oxygen inlet pipeline (3). The oxygen exhaust pipe (4) is located at the cathode outlet of the fuel cell stack (1); The oxygen inlet pipeline (3) and the oxygen outlet pipeline (4) are both connected to the third heat exchanger (10). The oxygen outlet pipeline (4) is also connected to the hydrogen outlet pipeline (5). The connection point of the oxygen outlet pipeline (4) and the hydrogen outlet pipeline (5) is located before the input end of the third heat exchanger (10).

13. A fuel cell system according to claim 12, characterized in that, The air compressor (21) is located at the output or input end of the third heat exchanger (10).

14. A self-pressurization method for a fuel cell system according to claim 1, characterized in that, Includes the following steps: The pressure data of the gas pillow area inside the liquid hydrogen cylinder (8) is monitored by the pressure detection component; When the monitored pressure data is lower than the first pressure threshold, the control component will control the self-pressurizing pipeline (6) to open; Hydrogen separated by the gas-liquid separator (22) is introduced into the interior of the first heat exchanger (9) through the self-pressurization pipeline (6) and exchanges heat with the liquid hydrogen in the liquid hydrogen bottle (8) to increase the pressure in the gas pillow area of ​​the liquid hydrogen bottle (8). After heat exchange, the hydrogen returns to the hydrogen inlet pipeline (2) through the self-pressurization pipeline (6) and re-enters the fuel cell stack (1) for reaction. When the pressure data of the gas pillow area inside the liquid hydrogen cylinder (8) monitored by the pressure detection component is higher than the first pressure threshold and lower than the second pressure threshold, the control component controls the self-pressurization pipeline (6) to close.

15. The self-pressurization method for a fuel cell system according to claim 14, characterized in that, The first pressure threshold is the minimum pressure required to ensure that liquid hydrogen can flow out of the liquid hydrogen bottle (8) stably, and the second pressure threshold is the safe pressure that the gas pillow area inside the liquid hydrogen bottle (8) can withstand.

16. A vehicle, characterized in that, The vehicle includes the fuel cell system as described in claim 1.

Images