Multifunctional ejector of fuel cell and hydrogen supply circulating system

Abstract

The invention discloses a multifunctional ejector of a fuel cell, which comprises a valve seat and an ejector body which are connected with each other, and also comprises a heat exchanger for heating hydrogen before entering a fuel cell stack by using waste heat, and the heat exchanger is integrated on the valve seat. The valve seat is provided with a shut-off valve used for controlling the opening and closing states of the hydrogen source opening and a proportional valve used for adjusting fuel supply. The hydrogen supply circulating system comprises a fuel cell stack and the fuel cell multifunctional ejector, the multifunctional ejector is arranged on the fuel cell stack, a gas-water separator is arranged on the fuel cell stack corresponding to a stack hydrogen outlet, a stack hydrogen backflow port connected with the ejector is formed in the top of the gas-water separator, and the fuel cell hydrogen backflow port is connected with the ejector. The bottom of the gas-water separator is connected with a drain pipe. The monomer performance at the anode inlet of the fuel cell stack is improved, and the working efficiency of the fuel cell stack and the monomer consistency of the stack are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a multifunctional ejector for fuel cells and a hydrogen supply circulation system. Background Art

[0002] As one of the functional subsystems of the fuel cell system, the fuel cell hydrogen supply and circulation system plays the role of hydrogen supply, humidification, and residual hydrogen circulation; it is of great significance to improve the reaction efficiency, working life, and hydrogen-related safety of the fuel cell system. Due to the small number of fuel cell vehicles and high costs, the industrialization of fuel cells is slow, and there are many deficiencies in design and reliability. On the one hand, the anode solutions of the fuel cell systems currently on the market can be roughly divided into two technical routes. The first technical route is the ejector solution, which is a passive solution that uses high-speed flowing new hydrogen to generate negative pressure and reflux the hydrogen at the anode outlet of the stack to improve the utilization rate of hydrogen; the advantages are: no auxiliary power consumption, simple and reliable, and low cost; the disadvantages are: in the low power range of the fuel cell system, due to the slow gas flow rate and insufficient ejection efficiency, the performance of the fuel cell system is poor. The second technical route is the hydrogen pump solution, which is an active solution. It uses the rotation of the motor to do work, forcing the residual hydrogen at the anode outlet to flow back to the anode inlet to participate in the reaction again, thereby improving the hydrogen utilization rate. The advantages are: stable operation and better performance; the disadvantages are: increased parasitic power consumption of the fuel cell system and poor NVH performance.

[0003] On the other hand, considering that when the working environment temperature is low, due to the large temperature difference between the high-temperature residual hydrogen refluxed at the anode outlet and the low-temperature hydrogen in the hydrogen bottle, condensation and water accumulation problems are very likely to occur after the ejector merges; after the condensed water enters the fuel cell stack with the hydrogen, it may hinder the transmission of the reaction gas, and then cause the cell voltage at the anode inlet of the fuel cell stack to drop, affecting the working efficiency of the stack and the consistency of the stack cells.

[0004] For example, patent CN118398839A discloses a fuel cell hydrogen supply circulation system and control method, which includes a fuel cell stack, wherein the inlet of the fuel cell stack is connected to an integrated ejector via a hydrogen inlet pipeline, and the outlet of the fuel cell stack is connected to a hydrogen inlet pipeline via a gas-water separator and a hydrogen return pipeline, a hydrogen circulation pump is arranged in the hydrogen return pipeline, and the hydrogen return pipeline is connected to the integrated ejector via a bypass pipeline; the above-mentioned problems exist, which affect the working efficiency of the stack and the consistency of the stack cells. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a fuel cell multifunctional ejector and a hydrogen supply circulation system, which can avoid the problem of hydrogen condensation water at low temperatures hindering gas transmission, and effectively improve the working efficiency of the fuel cell stack and the consistency of the monomers.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A multifunctional fuel cell ejector comprises a connected valve seat and an ejector body, and also comprises a heat exchanger for heating hydrogen before entering a fuel cell stack using waste heat, wherein the heat exchanger is integrated on the valve seat, and the valve seat is provided with a shut-off valve for controlling the opening / closing state of a hydrogen gas source opening and a proportional valve for adjusting fuel supply.

[0008] A medium pressure sensor is arranged on the valve seat corresponding to the proportional valve.

[0009] A hydrogen inlet pressure sensor and a hydrogen inlet temperature sensor are provided at corresponding outlet positions on the ejector body for detecting the temperature and pressure information of the hydrogen flowing into the fuel cell stack and reporting the signal to the fuel cell system controller.

[0010] The valve seat is provided with a hydrogen concentration sensor for detecting the hydrogen concentration on the anode side of the fuel cell system.

[0011] The heat exchanger is arranged on the top of the valve seat, and is provided with a heat exchanger heat medium inlet and a heat exchanger heat medium outlet for connecting to the fuel cell system cooling pipeline to utilize the waste heat of the fuel cell to heat the hydrogen; the heat exchanger is provided with a heat exchanger refrigerant inlet for connecting to the vehicle-mounted hydrogen supply system and a heat exchanger refrigerant outlet for connecting the corresponding shut-off valve to the internal flow channel of the valve seat.

[0012] A hydrogen supply circulation system comprises a fuel cell stack and a multifunctional ejector for the fuel cell, wherein the multifunctional ejector is arranged on the fuel cell stack, a gas-water separator is arranged on the fuel cell stack corresponding to the hydrogen outlet of the stack, a stack hydrogen reflux port connected to the ejector is arranged on the top of the gas-water separator, and a drain pipe is connected to the bottom of the gas-water separator.

[0013] A heating solenoid valve for heating and breaking ice in extreme situations is provided on the gas-water separator corresponding to the drain pipe.

[0014] The gas-water separator is provided with a hydrogen outlet pressure sensor and a hydrogen outlet temperature sensor, and a nitrogen exhaust valve for regularly exhausting nitrogen is provided in the middle of the gas-water separator.

[0015] It also includes a hydrogen circulation pump. The stack hydrogen reflux port on the gas-water separator is connected to the inlet of the hydrogen circulation pump. A connecting port connected to the valve seat of the ejector is provided at the top of the hydrogen circulation pump, and a hydrogen pump drain pipe is provided at the bottom of the hydrogen circulation pump.

[0016] In the described system, when the fuel cell system is in the low power stage, the system controls the hydrogen circulation pump to start actively to compensate for the amount of hydrogen return; when the fuel cell system is in the high power stage, the system only controls the hydrogen circulation pump to maintain low-speed rotation, and the residual hydrogen refluxed at the electric anode outlet passes through water, the hydrogen circulation pump, and the ejector in turn and reaches the anode inlet of the stack again to participate in the reaction, thereby improving the hydrogen utilization rate.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The multifunctional ejector and hydrogen supply circulation system of the fuel cell is reasonably designed. Combining the advantages of the ejector and the hydrogen pump, a new hydrogen supply circulation scheme is combined to effectively improve the hydrogen utilization rate and reduce auxiliary power consumption. By optimizing the integrated scheme of the traditional ejector, waste heat is used to heat the hydrogen before entering the fuel cell stack, thereby improving the single-cell performance at the anode inlet of the fuel cell stack, and improving the working efficiency of the fuel cell stack and the consistency of the stack single-cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following is a brief description of the contents and symbols in the drawings of this specification:

[0020] Figure 1 It is a front view of the hydrogen supply circulation system of the present invention.

[0021] Figure 2 It is a side view of the hydrogen supply circulation system of the present invention.

[0022] Figure 3 This is a schematic diagram of the hydrogen supply circulation system of the present invention.

[0023] Figure 4 It is a front view of the multifunctional ejector of the present invention.

[0024] Figure 5 It is a cross-sectional view of the multifunctional ejector of the present invention.

[0025] Figure 6 It is an isometric view of the multifunctional ejector of the present invention.

[0026] Figure 7 This is a schematic diagram of the structure of the hydrogen supply circulation system of the present invention.

[0027] Figure 8 It is a schematic diagram of the water separator of the present invention.

[0028] Fig. 9 It is a schematic diagram of the hydrogen circulation pump of the present invention.

[0029] In the figure:

[0030] 1- fuel cell stack; 2- multi-function ejector; 3- (hydrogen pump-ejector) connection port; 4- hydrogen circulation pump; 5- hydrogen outlet pressure sensor; 6- hydrogen outlet temperature sensor; 7- gas-water separator; 8- drain pipe; 9- tail exhaust mixing pipe; 10- hydrogen pump drain pipe; 11- nitrogen exhaust pipe; 12- drain valve; 13- heating solenoid valve; 14- nitrogen exhaust valve; 15- shut-off valve; 16- heat exchanger; 17- medium pressure sensor; 18- proportional valve; 19- ejector; 20- hydrogen inlet pressure sensor; 21- hydrogen inlet temperature sensor; 2 2-hydrogen concentration sensor; 23-ejector nozzle; 24-ejector channel; 25-heat exchanger heat medium inlet; 26-heat exchanger refrigerant outlet; 27-ejector valve seat; 28-heat exchanger heat medium outlet; 29-heat exchanger refrigerant inlet; 30-fuel cell stack hydrogen inlet; 31-fuel cell stack coolant inlet; 32-fuel cell stack air outlet; 33-fuel cell stack hydrogen reflux port; 34-fuel cell stack hydrogen outlet; 35-fuel cell stack coolant outlet; 36-fuel cell stack air inlet; 37-moisture baffle; 38-hydrogen circulation pump hydrogen return port; 39-hydrogen circulation pump drain port. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention will be further explained in detail below through the description of embodiments with reference to the accompanying drawings.

[0032] like Figures 1 to 9 As shown, the multifunctional fuel cell ejector includes a connected valve seat, an ejector body, and a heat exchanger that utilizes waste heat to heat hydrogen before entering the fuel cell stack; the heat exchanger is integrated on the valve seat, and the integrated arrangement has a compact structure.

[0033] The valve seat is provided with a shut-off valve for controlling the opening / closing status of the hydrogen gas source and a proportional valve for adjusting the fuel supply; a medium-pressure pressure sensor is provided on the valve seat corresponding to the proportional valve, and the proportional valve is responsible for adjusting the hydrogen flow and pressure in the fuel stack to meet the system fuel supply requirements under different operating points.

[0034] The ejector body is provided with a hydrogen inlet pressure sensor and a hydrogen inlet temperature sensor at the corresponding outlet position, which are used to detect the temperature and pressure information of the hydrogen flowing into the fuel cell stack and report the signal to the fuel cell system controller. The valve seat is provided with a hydrogen concentration sensor for detecting the hydrogen concentration on the anode side of the fuel cell system, which is integrated and compact.

[0035] The heat exchanger is arranged on the top of the valve seat, and is provided with a heat exchanger heat medium inlet and a heat exchanger heat medium outlet for connecting to the fuel cell system cooling pipeline to utilize the waste heat of the fuel cell to heat the hydrogen; the heat exchanger is provided with a heat exchanger refrigerant inlet for connecting to the vehicle-mounted hydrogen supply system and a heat exchanger refrigerant outlet for connecting the corresponding shut-off valve to the internal flow channel of the valve seat.

[0036] The shut-off valve, heat exchanger, medium-pressure pressure sensor, proportional valve, ejector, temperature sensor, and pressure sensor are integrated in this multifunctional ejector in sequence; the shut-off valve is responsible for controlling the shut-off of the hydrogen gas source inlet entering the fuel cell system, the heat exchanger is responsible for heating the low-temperature hydrogen flowing out of the hydrogen bottle, the medium-pressure pressure sensor is responsible for detecting the pressure of the low-temperature hydrogen, the proportional valve is responsible for controlling the opening of the hydrogen flow entering the fuel cell system, the ejector is responsible for reflux ejection of the hydrogen at the anode outlet, and the temperature sensor and pressure sensor behind the ejector are responsible for detecting the temperature and pressure of the hydrogen entering the fuel cell stack; at the same time, a hydrogen concentration sensor is integrated outside the ejector to detect the hydrogen concentration on the anode side of the fuel cell system. This multifunctional ejector has a high degree of integration and can effectively improve the performance of the fuel cell system in conjunction with the system control strategy.

[0037] The hydrogen supply circulation system of the present invention comprises a fuel cell stack and the multifunctional ejector of the fuel cell, the multifunctional ejector is arranged on the fuel cell stack, the fuel cell stack is provided with a gas-water separator corresponding to the hydrogen outlet of the stack, the top of the gas-water separator is provided with a stack hydrogen reflux port connected to the ejector, and the bottom of the gas-water separator is connected with a drain pipe. In the system, when the fuel cell system is in the low power section, the system controls the hydrogen circulation pump to be turned on actively to compensate for the amount of hydrogen return; when the fuel cell system is in the high power section, the system only controls the hydrogen circulation pump to maintain low-speed rotation, and the residual hydrogen refluxed at the anode outlet of the electric push passes through the water, the hydrogen circulation pump, and the ejector successively to reach the anode inlet of the stack again to participate in the reaction, thereby improving the utilization rate of hydrogen.

[0038] The corresponding drain pipe on the gas-water separator is equipped with a heating solenoid valve for heating and breaking ice in extreme cases. The gas-water separator is equipped with a hydrogen outlet pressure sensor and a hydrogen outlet temperature sensor, and a nitrogen discharge valve in the middle of the gas-water separator for regular discharge of nitrogen.

[0039] A hydrogen circulation pump is arranged above the gas-water separator, the stack hydrogen reflux port on the gas-water separator is connected to the inlet of the hydrogen circulation pump, a connection port connected to the valve seat of the ejector is arranged on the top of the hydrogen circulation pump, and a hydrogen pump drain pipe is arranged at the bottom of the hydrogen circulation pump. A tail discharge mixing pipe is arranged, and the hydrogen pump drain pipe, nitrogen discharge pipe and drain pipe are merged at the tail end, and nitrogen and liquid water are discharged out of the system through the tail discharge mixing pipe 9, which has a compact structure, occupies little space and is convenient for layout.

[0040] The hydrogen supply circulation system structure designed by the present invention is a scheme of connecting an ejector and a hydrogen pump in series. When the fuel cell system is in the low power stage, the system controls the hydrogen pump to start actively to compensate for the amount of hydrogen return; when the fuel cell system is in the high power stage, the system only controls the hydrogen pump to maintain low-speed rotation, and the residual hydrogen refluxed at the anode outlet passes through the water, hydrogen pump, and ejector in turn before reaching the anode inlet of the stack again to participate in the reaction, thereby improving the utilization rate of hydrogen.

[0041] The multifunctional fuel cell ejector and hydrogen supply circulation system of the present invention are reasonably designed, and a novel hydrogen supply circulation scheme is combined by combining the advantages of the ejector and the hydrogen pump, which effectively improves the utilization rate of hydrogen and reduces auxiliary power consumption; by optimizing the integration scheme of the traditional ejector, waste heat is used to heat the hydrogen before entering the fuel cell stack, thereby improving the single cell performance at the anode inlet of the fuel cell stack, and improving the working efficiency of the fuel cell stack and the consistency of the single cells of the stack.

[0042] Preferred embodiments of the present invention are:

[0043] like Figure 1 and Figure 2 As shown: the hydrogen supply circulation system is arranged at the tail end of the fuel cell stack 1, and the hydrogen enters the fuel cell stack 1 from the multifunctional ejector 2 to participate in the reaction. When the hydrogen reacts inside the fuel cell stack 1, it flows into the water 7 for gas-liquid separation; the separated liquid water enters the drain pipe 8 through the drain valve 12. On the one hand, considering that in a low temperature environment, liquid water may freeze and hinder the drain valve 12 from draining, it is necessary to integrate a heating solenoid valve 13 at the tail of the water 7 for heating and breaking ice in extreme cases. On the other hand, because the air contains nitrogen, when the fuel reacts inside the fuel cell 1, the nitrogen will pass through the proton exchange membrane to the hydrogen side, dilute the fuel concentration, and affect the working efficiency of the fuel cell stack 1. Therefore, it is necessary to integrate a nitrogen exhaust valve 14 in the water 7, and the fuel cell system controller (FCU) regularly controls the nitrogen exhaust valve 14 to open, and discharge the nitrogen in the cavity of the fuel cell stack 1 into the nitrogen exhaust pipe 11 to improve the working efficiency of the system. The hydrogen outlet pressure sensor 5 and the hydrogen outlet temperature sensor 6 are used to detect the pressure and temperature of the hydrogen separated from the water 7, and report the signal to the fuel cell system controller (FCU). The remaining hydrogen separated from the water 7 reaches the hydrogen circulation pump 4, and the remaining hydrogen passes through the (hydrogen pump-ejector) after being pressurized. Connection port 3 circulates to the multifunctional ejector 2 and enters the fuel cell stack 1 again to participate in the reaction. The hydrogen circulation pump 4 has a hydrogen pump drain pipe 10 at the bottom. The hydrogen pump drain pipe 10, the nitrogen drain pipe 11 and the drain pipe 8 are combined at the tail end, and the nitrogen and liquid water are discharged out of the system through the tail discharge mixing pipe 9.

[0044] like Figure 3As shown: This is the schematic diagram of the fuel cell hydrogen supply circulation system, in which hydrogen flows out from the pressure reducing valve of the vehicle-mounted hydrogen supply system and reaches the integrated ejector; after being heated by the heat exchanger, it enters the anode inlet of the fuel cell stack for reaction. After the hydrogen completes the reaction inside, it reaches the water at the anode outlet of the fuel cell stack for gas-liquid separation, and the separated liquid water is discharged by the drain valve and discharged after reaching the tail exhaust; when the fuel cell engine is in the low power state, due to the insufficient ejection efficiency of the ejector, the hydrogen pump is started, and the separated reflux hydrogen reaches the ejector through the hydrogen pump, and finally enters the anode inlet of the stack again to participate in the reaction. When the fuel cell engine is in the medium and high power state, the ejector has a better ejection effect, and the hydrogen pump only maintains low-speed rotation; after the refluxed hydrogen reaches the ejector from the hydrogen pump, it enters the anode inlet of the stack again to participate in the reaction. Considering that the proton exchange membrane can play the role of separating the anode and cathode of the fuel cell, since it cannot be completely physically isolated, the nitrogen and other impurity gases in the cathode will gradually penetrate the anode side through the proton exchange membrane, slowly accumulate over time, and cause the hydrogen on the anode side to be diluted. When the fuel concentration is lower than 50%, the reaction efficiency of the fuel cell engine may be seriously affected. Therefore, it is necessary to set a nitrogen exhaust valve in the anode side loop of the fuel cell stack to regularly discharge nitrogen and other impurity gases on the anode side of the fuel cell. In view of the above analysis, the design of the present invention is completed.

[0045] like Figure 4 and Figure 5 Shown: the appearance and structure of the multifunctional ejector. After hydrogen flows out from the vehicle-mounted hydrogen supply system, it first reaches the shut-off valve 15, which is responsible for controlling the opening / closing state of the hydrogen gas source; after the hydrogen passes through the shut-off valve 15, it reaches the heat exchanger 16; after the low-temperature hydrogen in the hydrogen bottle is heated by the heat exchanger 16, it reaches the proportional valve 18 through the medium-pressure pressure sensor 17. The proportional valve 18 is responsible for adjusting the hydrogen flow and pressure in the fuel cell stack to meet the system fuel supply requirements under different operating points. After the hydrogen passes through the proportional valve 18, it reaches the ejector 19. The ejector nozzle 23 is a conical object. It uses the Venturi tube principle generated when hydrogen flows at high speed to generate negative pressure, driving the reflux hydrogen through the ejector channel 24 into the fuel cell stack. The hydrogen inlet pressure sensor 20 and the hydrogen inlet temperature sensor 21 are responsible for detecting the temperature and pressure information of the hydrogen flowing into the fuel cell stack, and reporting the signal to the fuel cell system controller (FCU) for analysis. The multifunctional ejector is also externally integrated with a hydrogen concentration sensor 22 for detecting the hydrogen concentration on the anode side of the fuel cell system. When an abnormality is detected, the fuel cell system can choose to actively reduce power or perform an emergency shutdown according to the fault level to ensure the safety of the fuel cell vehicle and the environment.

[0046] like Figure 6The figure shows an isometric side view of the multifunctional ejector. The heat exchanger 16 is arranged on the top of the ejector valve seat 27; the heat exchanger heat medium inlet 25 and the heat exchanger heat medium outlet 28 are connected to the cooling pipeline of the fuel cell system, and the hydrogen is heated by the waste heat in the reaction process of the fuel cell system. The heat exchanger refrigerant inlet 29 is connected to the vehicle-mounted hydrogen supply system, and the heat exchanger refrigerant outlet 26 is connected to the internal flow channel of the ejector valve seat 27.

[0047] like Figure 7 and Fig. 9 The figure shows the hydrogen supply circulation system and hydrogen pump structure. After the hydrogen reacts inside the fuel cell stack 1, it reaches the water 7 from the stack hydrogen outlet 34. The residual hydrogen enters the stack hydrogen reflux port 33 after being separated inside the water 7. The stack hydrogen reflux port 33 and the hydrogen circulation pump hydrogen return port 38 are connected inside the fuel cell stack 1, and the (hydrogen pump-ejector) connection port 3 and the hydrogen circulation pump hydrogen return port 38 are connected inside the hydrogen circulation pump 4. The residual hydrogen separated by the water 7 passes through the hydrogen circulation pump 4 and finally reaches the stack hydrogen inlet 30. A hydrogen circulation pump drain port 39 is arranged at the bottom of the hydrogen circulation pump, and the condensed water in the hydrogen circulation pump 4 is discharged out of the system through the hydrogen circulation pump drain port 39.

[0048] like Figure 8 As shown: It is a moisture structure. After hydrogen flows out from the fuel cell hydrogen outlet 34, it collides with the moisture baffle 37 many times and reaches the fuel cell hydrogen reflux port 33 to complete the gas-liquid separation process.

[0049] Through the creative application of the present invention, the combination scheme of the existing hydrogen pump and the ejector is optimized, the system integration is improved, and the system working efficiency is optimized; the low-temperature hydrogen before entering the fuel cell stack is heated by the multifunctional ejector, which has high heat exchange efficiency and low cost, and can effectively reduce the possibility of flooding of the fuel cell. The scheme of the present invention is conducive to improving the overall reaction efficiency of the fuel cell engine and can provide a new idea for the design of the hydrogen supply circulation system.

[0050] The above is only an explanation of the preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0051] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A multifunctional fuel cell ejector, comprising a valve seat and an ejector body connected to each other, characterized in that: It also includes a heat exchanger that uses waste heat to heat the hydrogen before entering the fuel cell stack. The heat exchanger is integrated on the valve seat, and the valve seat is provided with a shut-off valve for controlling the open / closed state of the hydrogen gas source opening and a proportional valve for adjusting the fuel supply.

2. The multifunctional fuel cell ejector as claimed in claim 1, characterized in that: A medium pressure sensor is arranged on the valve seat corresponding to the proportional valve.

3. The multifunctional fuel cell ejector as claimed in claim 1, characterized in that: A hydrogen inlet pressure sensor and a hydrogen inlet temperature sensor are provided at corresponding outlet positions on the ejector body for detecting the temperature and pressure information of the hydrogen flowing into the fuel cell stack and reporting the signal to the fuel cell system controller.

4. The multifunctional fuel cell ejector as claimed in claim 1, characterized in that: The valve seat is provided with a hydrogen concentration sensor for detecting the hydrogen concentration on the anode side of the fuel cell system.

5. The multifunctional fuel cell ejector as claimed in claim 1, characterized in that: The heat exchanger is arranged on the top of the valve seat, and is provided with a heat exchanger heat medium inlet and a heat exchanger heat medium outlet for connecting to the fuel cell system cooling pipeline to utilize the waste heat of the fuel cell to heat the hydrogen; the heat exchanger is provided with a heat exchanger refrigerant inlet for connecting to the vehicle-mounted hydrogen supply system and a heat exchanger refrigerant outlet for connecting the corresponding shut-off valve to the internal flow channel of the valve seat.

6. A hydrogen supply circulation system, comprising a fuel cell stack, characterized in that: It also includes the multifunctional ejector for fuel cells as described in any one of claims 1 to 5, the multifunctional ejector is arranged on the fuel cell stack, a gas-water separator is provided on the fuel cell stack corresponding to the hydrogen outlet of the stack, a stack hydrogen reflux port connected to the ejector is provided on the top of the gas-water separator, and a drain pipe is connected to the bottom of the gas-water separator.

7. The hydrogen supply circulation system according to claim 6, characterized in that: A heating solenoid valve for heating and breaking ice in extreme situations is provided on the gas-water separator corresponding to the drain pipe.

8. The hydrogen supply circulation system according to claim 6, characterized in that: The gas-water separator is provided with a hydrogen outlet pressure sensor and a hydrogen outlet temperature sensor, and a nitrogen exhaust valve for regularly exhausting nitrogen is provided in the middle of the gas-water separator.

9. The hydrogen supply circulation system according to claim 6, characterized in that: It also includes a hydrogen circulation pump. The stack hydrogen reflux port on the gas-water separator is connected to the inlet of the hydrogen circulation pump. A connecting port connected to the valve seat of the ejector is provided at the top of the hydrogen circulation pump, and a hydrogen pump drain pipe is provided at the bottom of the hydrogen circulation pump.

10. The hydrogen supply circulation system according to claim 9, characterized in that: In the described system, when the fuel cell system is in the low power stage, the system controls the hydrogen circulation pump to start actively to compensate for the amount of hydrogen return; when the fuel cell system is in the high power stage, the system only controls the hydrogen circulation pump to maintain low-speed rotation, and the residual hydrogen refluxed at the electric anode outlet passes through water, the hydrogen circulation pump, and the ejector in turn and reaches the anode inlet of the stack again to participate in the reaction, thereby improving the hydrogen utilization rate.

Images