Fuel cell multistage ejector, hydrogen supply system and control method

Abstract

The invention discloses a fuel cell multi-stage ejector, a hydrogen supply system and a control method.The fuel cell multi-stage ejector comprises a nozzle, a diffusion section, a suction chamber, a mixing chamber and a diffusion chamber, the suction chamber is arranged outside the diffusion section, an ejection fluid channel is arranged on the outer side of the suction chamber, and the suction chamber, the mixing chamber and the diffusion chamber are sequentially connected; the front end of the nozzle extends out of the suction chamber, the rear end of the nozzle is connected with an inlet of the diffusion section, and bionic ejector sawteeth are arranged at an outlet of the diffusion section. Sawteeth of the bionic ejector are designed on the basis of a shark gill structure, the ejection efficiency and the gas mixing effect are remarkably improved by optimizing tooth shape parameters, and meanwhile the hydrogen supply flow requirements under different working conditions are met. According to the multistage ejector, through structural innovation and bionic design, the problems that a traditional ejector is low in ejection coefficient and narrow in dynamic regulation and control range are solved, the multistage ejector can be widely applied to a fuel cell hydrogen supply system, and the hydrogen recovery rate and the energy utilization efficiency are improved.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cells, and more particularly, to a fuel cell multi-stage ejector, a hydrogen supply system and a control method thereof. Background Art

[0002] Hydrogen fuel cells convert chemical energy into electrical energy through the redox reaction of hydrogen and oxygen. Their efficiency is not limited by the Carnot cycle and they have advantages such as high specific energy, fast response speed, and zero pollution, and are widely used in fields such as automobiles, airplanes, and ships. To ensure the working efficiency of hydrogen fuel cells, hydrogen needs to be supplied in excess, thus generating the problem of treating unreacted hydrogen. The currently mainly adopted technical modes include the flow-through mode, the dead-end mode, and the recycle mode. Among them, the recycle mode has attracted much attention because it can reuse unreacted gas, improve the utilization rate of hydrogen energy, and prevent the accumulation of media from reducing the output efficiency. Commonly used recycling devices include recycle pumps and ejectors. For recycle pumps, although the regulation range is wide, there are problems such as corrosion risk, large vibration and noise, and additional power consumption; in addition, since oil cannot be used to lubricate the components in contact with gas to avoid contaminating the fuel cell catalyst or blocking pores, its application is limited to a certain extent. In contrast, ejectors are widely used in various fields due to their simple structure, no additional power consumption, low noise, etc., and have a relatively high stack efficiency among several recycling devices. However, the entrainment coefficient of an ejector is closely related to the nozzle size and structure, and optimizing the nozzle structure can improve the entrainment coefficient.

[0003] In the prior art, there is a hydrogen fuel cell ejector and a hydrogen recycling system. This technology only uses a single ejector as a recycling device. This solution is limited by the narrow working range brought about by the fixed geometry of the ejector, and the entrainment coefficient is not high; there is an integrated ejector, a fuel cell hydrogen supply system and its control method. This technology has two hydrogen supply modes. One is that hydrogen passes through the ejector, and the other is that hydrogen does not pass through the ejector. The diameters of the two pipelines are different. This solution is not suitable for the dynamic change of the fuel cell stack load under high power, and the entrainment coefficient is not high; there is a variable-condition dual-nozzle ejector recycling fuel cell system and its control method. This technology utilizes the self-characteristics of the dual-nozzle ejector and selects to use one nozzle or two nozzles to work simultaneously according to different operating modes of the fuel cell stack. This solution will increase the energy loss under high pressure when using a dual-nozzle ejector, resulting in a decrease in the entrainment coefficient of the ejector, and it is difficult to achieve the output power of a fuel cell stack with a higher hydrogen supply amount.

[0004] The main challenges currently faced by the fuel cell circulating hydrogen supply system using an ejector as a circulation device are as follows: First, in the face of the complex changes in the working conditions of the fuel cell in a specific usage scenario, the traditional ejector is difficult to flexibly adjust the hydrogen supply due to its fixed geometric structure to meet a wide range of needs. Secondly, in order to ensure the performance of the fuel cell, a hydrogen rate supply method is usually adopted, but the ejection coefficient of the traditional ejector is low, resulting in a low recovery rate of unreacted hydrogen and a waste of resources. Finally, in practical applications, it is necessary to increase the ejection coefficient of the ejector while ensuring a wide range of hydrogen supply. There is a trade-off between the two, which makes the system design more complicated. In summary, how to overcome the above-mentioned problems existing in the prior art and develop an ejector that can adapt to complex working conditions and effectively improve the hydrogen recovery rate has become a key issue that needs to be urgently solved by technicians in this field. Summary of the invention

[0005] The purpose of this application is to provide a fuel cell multi-stage ejector, a hydrogen supply system and a control method in order to overcome the existing technical defects. Through the design of bionic ejector sawtooth, the contradiction between the ejection coefficient and the hydrogen supply flow rate of the traditional ejector under different working pressures is solved, and the performance of the fuel cell multi-stage hydrogen supply system is improved.

[0006] The purpose of this application is achieved through the following technical solutions:

[0007] In the first aspect, the present application proposes a fuel cell multi-stage ejector, comprising: a nozzle 12, a diffuser section 15, an intake chamber 13, a mixing chamber 17 and a diffusion chamber 18, wherein the intake chamber 13 is arranged outside the diffusion section 15 and an ejection fluid channel 14 is arranged outside the intake chamber 13, and the intake chamber 13, the mixing chamber 17 and the diffusion chamber 18 are connected in sequence;

[0008] The front end of the nozzle 12 extends out of the suction chamber 13 , the rear end of the nozzle 12 is connected to the inlet of the diffuser section 15 , and the bionic ejector serrations 16 are arranged inside the outlet of the diffuser section 15 .

[0009] In a possible implementation, the diffuser section 15 includes a tapered section and a straight section, the top of the tapered section is connected to the rear end of the nozzle 12, and the bottom of the tapered section is connected to one end of the straight section.

[0010] In a possible implementation, the tooth ratio of the bionic ejector sawtooth 16 ranges from 0 to 0.4.

[0011] In a possible implementation, the tooth length ratio of the bionic ejector sawtooth 16 is in the range of 0-0.6.

[0012] In a possible implementation, the tooth width ratio of the bionic ejector sawtooth 16 is in the range of 0-0.4.

[0013] In a possible implementation, the tooth height ratio range of the bionic ejector serrations 16 is 0 - 0.6.

[0014] In a possible implementation, the tooth angle of the bionic ejector serrations 16 is selected according to the inlet pressure.

[0015] In a second aspect, the present application also proposes a hydrogen supply system, including a hydrogen storage tank 1, a pressure reducing valve 2, a hydrogen supply adjustment module, a fuel cell stack 5, a gas-liquid separator 6, a drain valve 7, a load module 8, an output power status monitor 9, and a control unit 10;

[0016] The hydrogen storage tank 1, the pressure reducing valve 2, the hydrogen supply adjustment module, the gas-liquid separator 6, and the drain valve 7 are connected in sequence, and the hydrogen supply adjustment module, the control unit 10, the output power status monitor 9, the fuel cell stack 5, and the load module 8 are connected in sequence;

[0017] The hydrogen supply adjustment module includes a plurality of hydrogen supply adjustment sub-modules, and each hydrogen supply adjustment sub-module includes a plurality of solenoid valves and a hydrogen fuel cell ejector according to any one of the first aspects.

[0018] In a possible implementation, the hydrogen supply adjustment sub-module is used to combine a plurality of hydrogen fuel cell ejectors through precise control of the solenoid valves to form multiple hydrogen supply modes, and the hydrogen supply modes include hydrogen bypassing the hydrogen fuel cell ejector and being directly transported, hydrogen flowing through each hydrogen fuel cell ejector independently, hydrogen passing through a plurality of hydrogen fuel cell ejectors in sequence to achieve stepped supply, and hydrogen being synchronously distributed to a plurality of hydrogen fuel cell ejectors to form cooperative supply.

[0019] In a third aspect, the present application also proposes a control method for a fuel cell hydrogen supply system, which is applied to the hydrogen supply system described in the second aspect, and the method includes:

[0020] Step S1, the load module 8 obtains the required demand power;

[0021] Step S2, the output power status monitor 9 monitors the demand power of the load module 8 in real time and transmits it to the control unit 10;

[0022] Step S3, after receiving the signal of the demand power, the control unit 10 judges the required demand power and the set hydrogen supply amount range, and matches the hydrogen supply mode with the corresponding hydrogen supply amount demand by controlling the opening and closing of the solenoid valve in real time; wherein the corresponding hydrogen supply mode is composed of multiple combination modes of "series, parallel, and single" connection and their pairwise combinations of different hydrogen fuel cell ejectors;

[0023] Step S4: When the required power of the load module 8 changes, repeat Steps S1 - S3 to adjust the solenoid valve in real time to control different hydrogen supply modes, enabling the hydrogen supply system to switch between different flow rates, meet the required power of different loads, and increase the recovery rate of unreacted hydrogen.

[0024] The main solution of the present application and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and claimed in the present application; and in the present application, (each non - conflicting alternative) alternatives and other alternatives can also be freely combined. Those skilled in the art can understand that there are various combinations according to the prior art and common general knowledge after understanding the solution of the present application, all of which are the technical solutions to be protected by the present application, and will not be exhaustively listed here.

[0025] The present application discloses a fuel cell multi - stage ejector, a hydrogen supply system and a control method. The fuel cell multi - stage ejector includes a nozzle, a diffuser section, a suction chamber, a mixing chamber and a diffuser chamber. The suction chamber is arranged outside the diffuser section, and an ejector fluid channel is arranged on the outside of the suction chamber. The suction chamber, the mixing chamber and the diffuser chamber are connected in sequence. The front end of the nozzle extends out of the suction chamber, the rear end of the nozzle is connected to the inlet of the diffuser section, and a bionic ejector serration is arranged at the outlet of the diffuser section. The bionic ejector serration is designed based on the shark gill structure. By optimizing the tooth shape parameters, the ejector efficiency and gas mixing effect are significantly improved, and at the same time, it can adapt to the hydrogen supply flow rate requirements under different working conditions. This multi - stage ejector solves the problems of low ejector coefficient and narrow dynamic regulation range of traditional ejectors through structural innovation and bionic design, and can be widely applied to fuel cell hydrogen supply systems to improve the hydrogen recovery rate and energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 Shows a schematic structural diagram of a fuel cell multi - stage ejector proposed in an embodiment of the present application.

[0028] Figure 2 Shows an internal schematic diagram of a fuel cell multi - stage ejector proposed in an embodiment of the present application.

[0029] Figure 3 Shows the curve of the axial pressure change of the ejector under different tooth number ratios proposed in an embodiment of the present application.

[0030] Figure 4Shows the "tooth number ratio - hydrogen supply flow rate - entrainment coefficient - inlet pressure" curve graph under different pressures proposed by the embodiments of the present application.

[0031] Figure 5 Shows the schematic diagram of "tooth length ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under low pressure proposed by the embodiments of the present application.

[0032] Figure 6 Shows the schematic diagram of "tooth length ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure proposed by the embodiments of the present application.

[0033] Figure 7 Shows the schematic diagram of "tooth width ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under low pressure proposed by the embodiments of the present application.

[0034] Figure 8 Shows the schematic diagram of "tooth width ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure proposed by the embodiments of the present application.

[0035] Figure 9 Shows the schematic diagram of "tooth height ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under low pressure proposed by the embodiments of the present application.

[0036] Figure 10 Shows the schematic diagram of "tooth height ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure proposed by the embodiments of the present application.

[0037] Figure 11 Shows the schematic diagram of "tooth angle - entrainment coefficient - hydrogen supply flow rate" of the ejector under low pressure proposed by the embodiments of the present application.

[0038] Figure 12 Shows the schematic diagram of "tooth angle - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure proposed by the embodiments of the present application.

[0039] Figure 13 Shows the schematic diagram of the serrated teeth of the bionic ejector proposed by the embodiments of the present application.

[0040] Figure 14 Shows the structural schematic diagram of the hydrogen supply system proposed by the embodiments of the present application.

[0041] Figure 15 Shows the structural schematic diagram of the hydrogen supply system with multiple hydrogen supply sub - modules proposed by the embodiments of the present application.

[0042] Reference Numerals: 1 - hydrogen storage tank; 2 - pressure reducing valve; 5 - fuel cell stack; 6 - gas-liquid separator; 7 - drain valve; 8 - load module; 9 - output power status monitor; 10 - control unit; 12 - nozzle; 13 - suction chamber; 14 - ejector fluid passage; 15 - diffusion section; 16 - sawtooth; 17 - mixing chamber; 18 - diffuser chamber; (31 - 36) - solenoid valve; (311 - 322) - solenoid valve; (41 - 44) - hydrogen fuel cell ejector. Detailed Embodiments

[0043] The following specific examples illustrate the embodiments of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0044] All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0045] In the prior art, the main problems faced by the fuel cell circulating hydrogen supply system are as follows: First, in the face of the complex changes in the working conditions of fuel cells in specific usage scenarios, due to the fixed structure of the ejector, it is difficult to match the wide-range adjustment of the hydrogen supply amount of the fuel cell stack; Second, to ensure the performance of the fuel cell, a hydrogen ratio supply is mostly adopted. The entrainment coefficient of the traditional ejector is low, and the recovery rate of the unreacted hydrogen is relatively low, resulting in a large amount of excess hydrogen being directly discharged into the atmosphere, causing a great waste of resources; Third, in the actual usage scenario of the fuel cell, there is a contradiction between the wide-range supply of hydrogen supply amount and the recovery of the entrainment coefficient of the ejector, where one increases while the other decreases.

[0046] Therefore, to solve the above technical problems, the embodiments of the present application propose a fuel cell multi-stage ejector, hydrogen supply system and control method. Through the design of the bionic ejector sawtooth, the contradiction between the entrainment coefficient and the hydrogen supply flow rate of the traditional ejector under different working pressures is solved, and the performance of the fuel cell multi-stage hydrogen supply system is improved. The following is a detailed explanation of it.

[0047] Please refer to Figure 1 , Figure 1The figure shows a schematic structural diagram of a fuel cell multi-stage ejector proposed in an embodiment of the present application, including: a nozzle 12, a diffuser section 15, a suction chamber 13, a mixing chamber 17, and a diffuser chamber 18. The suction chamber 13 is arranged outside the diffuser section 15, and an ejector fluid channel 14 is arranged on the outer side of the suction chamber 13. The suction chamber 13, the mixing chamber 17, and the diffuser chamber 18 are connected in sequence;

[0048] The front end of the nozzle 12 extends out of the suction chamber 13, the rear end of the nozzle 12 is connected to the inlet of the diffuser section 15, and a bionic ejector serration 16 is arranged inside the outlet of the diffuser section 15.

[0049] Based on Figure 1 , Figure 2 The figure shows an internal schematic diagram of a fuel cell multi-stage ejector proposed in an embodiment of the present application. The nozzle 12 is located at the front end of the entire ejector and is connected in sequence from left to right, used to accelerate the high-pressure gas entering the ejector to form a high-speed air flow to generate an entrainment effect.

[0050] The suction chamber 13 is immediately behind the nozzle 12, surrounding the outside of the diffuser section 15, introducing the external environment or unreacted hydrogen through the ejector fluid channel 14, using the high-speed air flow generated by the nozzle 12 to attract the surrounding medium, so as to achieve the ejector effect. The suction chamber 13 is provided with an ejector fluid channel 14, and this channel is connected to the unreacted hydrogen recovery system to ensure the recycling efficiency.

[0051] The diffuser section 15 is located between the rear end of the nozzle 12 and the front end of the mixing chamber 17, gradually decelerating and increasing the pressure of the high-speed gas flowing out of the nozzle 12. A bionic ejector serration 16 is arranged inside the outlet of the diffuser section 15, and these serrations can adjust their geometric features (such as the number of teeth, angle, length, width, and height) according to the pressure at the inlet of the nozzle 12 to optimize the ejector effect.

[0052] The mixing chamber 17 is located after the diffuser section 15 and before the diffuser chamber. In this area, the high-speed gas from the nozzle 12 is fully mixed with the external medium introduced through the suction chamber 13 and is ready to enter the diffuser chamber for further processing. The diffuser chamber 18, as the last part of the ejector, can further slow down the speed of the mixed gas and at the same time increase its pressure, and finally supply stable and appropriate hydrogen to the fuel cell stack for use.

[0053] The working process of the fuel cell multi-stage ejector is as follows: The high-pressure hydrogen stored in the hydrogen storage tank is regulated by a pressure reducing valve and then enters the gas supply circuit controlled by a solenoid valve. When the solenoid valve switches the path according to the control unit's instruction, the selected ejector combination starts to work. The serrated structure in the nozzle 12 will be adjusted according to the current pressure conditions to achieve the best ejection effect. The suction chamber introduces additional gas (such as unreacted hydrogen) through the ejector fluid channel and mixes it evenly with the high-speed gas flowing out of the nozzle 12 in the mixing chamber. Subsequently, after gradually decelerating and increasing the pressure in the diffuser section 15 and the diffuser chamber, the required hydrogen flow is finally provided to the fuel cell stack.

[0054] The diffuser section 15 includes a tapered section and a straight section. The top of the tapered section is connected to the rear end of the nozzle 12, and the bottom of the tapered section is connected to one end of the straight section.

[0055] The tapered section is located between the rear end of the nozzle 12 and the straight section, which can initially decelerate the high-speed gas flowing out of the nozzle 12 and guide the air flow into the straight section, helping to gradually reduce the air flow speed while increasing the pressure to ensure a smooth transition of the air flow. The straight section follows immediately after the tapered section and constitutes the main channel of the diffuser section 15, serving as a space for the gas to continue to decelerate and further increase the pressure.

[0056] The parameters such as the number of teeth, tooth angle, tooth length, tooth width, and tooth height of the bionic ejector serration 16 are related to the inlet pressure of the nozzle 12, and the entrainment coefficient and hydrogen supply flow are comprehensively considered.

[0057] The range of the tooth number ratio of the bionic ejector serration 16 is 0 - 0.4.

[0058] The tooth number ratio is the ratio of the current number of teeth to the maximum number of teeth. Different tooth number ratios are selected under different inlet pressures. A smaller tooth number ratio is selected under low-pressure conditions to avoid a decrease in the entrainment coefficient and hydrogen supply flow, ensuring that the system can still maintain high efficiency in a low-pressure environment. A larger tooth number ratio is selected under high-pressure conditions to enhance the entrainment ability through more serrations, significantly improving the entrainment coefficient and hydrogen supply flow, and thus improving the energy utilization rate of hydrogen.

[0059] Figure 3 The pressure change curve of the ejector axis under different tooth number ratios proposed in the embodiment of the present application is shown, which shows the influence of setting different tooth number ratios on the pressure curve at the central axis. In the case of having serrations 16, the pressure at the central axis will decrease, making the entrainment ability stronger and having a higher entrainment coefficient. Figure 4The graph of "tooth ratio - hydrogen supply flow - entrainment coefficient - inlet pressure" under different pressures proposed by the embodiments of the present application is shown. When the inlet pressure of the nozzle 12 is at a low pressure, using a high tooth ratio will not only reduce the entrainment coefficient, but also decrease the hydrogen supply flow. Therefore, a smaller tooth ratio should be selected under low-pressure conditions, while a larger tooth ratio should be selected under high-pressure conditions to increase the entrainment coefficient and the hydrogen supply flow.

[0060] The tooth length ratio range of the serrations 16 of the bionic ejector is 0 - 0.6.

[0061] The tooth length ratio is the ratio of the current tooth length to the maximum tooth length. The tooth length ratio is selected differently under different inlet pressures. A smaller tooth length ratio is selected under low-pressure conditions to avoid the decrease of the entrainment coefficient and the hydrogen supply flow, ensuring that the system can still maintain a high efficiency in a low-pressure environment. A larger tooth length ratio is selected under high-pressure conditions to enhance the entrainment ability through longer serrations, significantly improving the entrainment coefficient and the hydrogen supply flow, and thus increasing the energy utilization rate of hydrogen.

[0062] Figure 5 The schematic diagram of "tooth length ratio - entrainment coefficient - hydrogen supply flow" of the ejector under low pressure proposed by the embodiments of the present application is shown. In the case of having serrations 16, the pressure at the central axis will decrease, making the entrainment ability stronger and having a higher entrainment coefficient. Figure 6 The schematic diagram of "tooth length ratio - entrainment coefficient - hydrogen supply flow" of the ejector under high pressure proposed by the embodiments of the present application is shown. When the inlet pressure of the nozzle 12 is at a low pressure, using a high tooth length ratio will not only reduce the entrainment coefficient, but also decrease the hydrogen supply flow. Therefore, a smaller tooth length ratio should be selected under low-pressure conditions; while a larger tooth length ratio should be selected under high-pressure conditions to increase the entrainment coefficient and the hydrogen supply flow.

[0063] The tooth width ratio range of the serrations 16 of the bionic ejector is 0 - 0.4.

[0064] The tooth width ratio is the ratio of the current tooth width * number of teeth to the circumference of the nozzle outlet. The tooth width ratio is selected differently under different inlet pressures. A smaller tooth width ratio is selected under low-pressure conditions to avoid the decrease of the entrainment coefficient and the hydrogen supply flow, ensuring that the system can still maintain a high efficiency in a low-pressure environment. A larger tooth width ratio is selected under high-pressure conditions to enhance the entrainment ability through wider serrations, significantly improving the entrainment coefficient and the hydrogen supply flow, and thus increasing the energy utilization rate of hydrogen.

[0065] Figure 7 The schematic diagram of "tooth width ratio - entrainment coefficient - hydrogen supply flow" of the ejector under low pressure proposed by the embodiments of the present application is shown. It shows the influence of setting different tooth width ratios on the pressure curve at the central axis. In the case of having serrations 16, the pressure at the central axis will decrease, making the entrainment ability stronger and having a higher entrainment coefficient. Figure 8The figure shows the schematic diagram of "tooth width ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure in the embodiments of the present application. When the inlet pressure of the nozzle 12 is at a low pressure, using a high tooth width ratio will not only reduce the entrainment coefficient, but also decrease the hydrogen supply flow rate. Therefore, a smaller tooth width ratio should be selected under low pressure conditions; while a larger tooth width ratio should be selected under high pressure conditions to increase the entrainment coefficient and hydrogen supply flow rate.

[0066] The tooth height ratio of the bionic ejector sawtooth 16 ranges from 0 to 0.6.

[0067] The tooth height ratio is the ratio of the current tooth height to the maximum tooth height. The tooth height ratio is selected differently at different inlet pressures. Selecting a smaller tooth height ratio under low pressure conditions ensures the stability of the entrainment coefficient and hydrogen supply flow rate, preventing performance degradation caused by overly high sawteeth. Selecting a larger tooth height ratio under high pressure conditions enhances the entrainment effect and increases the hydrogen supply flow rate, making the system more efficient in a high-pressure environment.

[0068] Figure 9 The figure shows the schematic diagram of "tooth height ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under low pressure in the embodiments of the present application. It shows the influence of setting different tooth height ratios on the pressure curve at the central axis. In the case of having the sawtooth 16, the pressure at the central axis will decrease, making the entrainment ability stronger and having a higher entrainment coefficient. Figure 10 The figure shows the schematic diagram of "tooth height ratio - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure in the embodiments of the present application. When the inlet pressure of the nozzle 12 is at a low pressure, using a high tooth height ratio will not only reduce the entrainment coefficient, but also decrease the hydrogen supply flow rate. Therefore, a smaller tooth height ratio should be selected under low pressure conditions, and a larger tooth height ratio should be selected under high pressure conditions to increase the entrainment coefficient and hydrogen supply flow rate.

[0069] The tooth angle of the bionic ejector sawtooth 16 is selected according to the inlet pressure.

[0070] In the low-pressure range, the tooth angle is selected to be in an inclined arrangement (not 90°), that is, the sawteeth are at a certain inclined angle relative to the central axis. When the inlet pressure is low, using an inclined arrangement can increase the entrainment effect of the fluid, improve the entrainment coefficient, and thus improve the overall efficiency of the system. In the high-pressure range, the tooth angle is selected to be in a vertical arrangement (90°), that is, the sawteeth are arranged perpendicular to the central axis. Under high-pressure conditions, the vertical arrangement can enhance the direct impact force of the fluid, further improve the entrainment coefficient and hydrogen supply flow rate, and ensure the efficient operation of the system in a high-pressure environment.

[0071] Figure 11The figure shows a schematic diagram of the "tooth angle - entrainment coefficient - hydrogen supply flow rate" of the ejector under low pressure in the embodiments of the present application. It shows the influence of setting different tooth angles on the pressure curve at the central axis. The inclined arrangement of sawteeth can reduce the pressure at the central axis, enhance the entrainment ability, and have a higher entrainment coefficient. Figure 12 The figure shows a schematic diagram of the "tooth angle - entrainment coefficient - hydrogen supply flow rate" of the ejector under high pressure in the embodiments of the present application. When the inlet pressure of the nozzle 12 is at low pressure, the inclined arrangement not only improves the entrainment coefficient but also increases the hydrogen supply flow rate. In the case of high pressure, the vertical arrangement significantly enhances the entrainment effect and the hydrogen supply flow rate.

[0072] The shape of the sawteeth 16 can be rectangular, triangular, or other derivative shapes, or it can be in the form of adding auxiliary teeth to the main teeth, with the auxiliary teeth referring to the main teeth; the sawteeth of the bionic ejector can extend directly outwards or be in a rotating or spiral shape; the diffuser section 15 of the bionic ejector nozzle can be set as a spiral tube, a straight tube, etc. according to different requirements, such as increasing gas stability and reducing energy loss.

[0073] Figure 13 The figure shows a schematic diagram of the sawteeth of the bionic ejector in the embodiments of the present application. The sawteeth are rectangular, with the height h and width w of each sawtooth clearly marked. The sawteeth are evenly distributed along the circular edge, and the distance l between each sawtooth is also marked to ensure the uniform distribution of the sawteeth on the entire circumference. The height h of the sawteeth is prominently marked and arranged at a certain angle in an inclined manner to form a spiral structure, which helps to enhance the turbulent effect of the fluid. In terms of the design of the diffuser section of the nozzle, the angle θ is marked at the central position, which determines the opening size of the diffuser section of the nozzle and thus affects the diffusion effect of the fluid.

[0074] The present application proposes a fuel cell multi-stage ejector, including a hydrogen storage tank 1, a pressure reducing valve 2, a hydrogen supply adjustment module, a fuel cell stack 5, a gas-liquid separator 6, a drain valve 7, a load module 8, an output power status monitor 9, and a control unit 10;

[0075] The hydrogen storage tank 1, the pressure reducing valve 2, the hydrogen supply adjustment module, the gas-liquid separator 6, and the drain valve 7 are connected in sequence, and the hydrogen supply adjustment module, the control unit 10, the output power status monitor 9, the fuel cell stack 5, and the load module 8 are connected in sequence;

[0076] The hydrogen supply adjustment module includes a plurality of hydrogen supply adjustment sub-modules, and each hydrogen supply adjustment sub-module includes a plurality of solenoid valves and a plurality of hydrogen fuel cell ejectors.

[0077] Figure 14The structural schematic diagram of the hydrogen supply system proposed by the embodiments of the present application is shown. The hydrogen storage tank stores high-pressure hydrogen. The pressure reducing valve reduces the high-pressure hydrogen in the hydrogen storage tank to a pressure suitable for use. The solenoid valve controls the hydrogen flow path to achieve hydrogen supply regulation in different modes. The bionic ejector is used to enhance the recovery efficiency of unreacted hydrogen and improve the energy utilization rate. Each ejector has different nozzle structure sizes and can be adjusted according to requirements. The fuel cell stack is the core component for generating electric energy. The unreacted gas flows to the ejector after passing through the gas-liquid separator. The gas-liquid separator separates the unreacted gas and liquid. The drain valve discharges the condensed water or other liquids in the system. The output power state monitor monitors the required power of the load module in real time and synchronously transmits the data signal to the control unit. The control unit controls the opening and closing of the solenoid valve in real time according to the power demand transmitted in real time to match the hydrogen supply mode corresponding to the required hydrogen supply volume.

[0078] In the hydrogen supply regulation sub-module, through the precise control of the solenoid valve, multiple hydrogen fuel cell ejectors can be flexibly combined to form multiple hydrogen supply modes: (1) Hydrogen bypasses the hydrogen fuel cell ejector and is directly transported; (2) Hydrogen can flow through each hydrogen fuel cell ejector independently; (3) Hydrogen sequentially passes through multiple hydrogen fuel cell ejectors to achieve cascade supply; (4) Hydrogen is synchronously distributed to multiple hydrogen fuel cell ejectors to form cooperative supply.

[0079] The hydrogen supply system has multiple operating modes, and its mode adjustment dynamically matches the changes in the corresponding hydrogen supply mode according to the required power of the load module. In the single ejector mode, one ejector is selected as the circulation device, which is achieved by the opening and closing of a specific solenoid valve. In the series mode, multiple ejectors work in series, which is suitable for situations where a higher ejector effect and hydrogen recovery rate are required. In the parallel mode, multiple ejectors work in parallel, which is suitable for situations where a large hydrogen supply flow is required at high power. At the same time, in order to gently adapt to the scenarios during the operation of the fuel cell, it is often necessary to dynamically adjust various combinations of two-by-two combinations between multiple ejectors. In the combined mode, different modes of "single, series, parallel" and their two-by-two combinations can be flexibly combined according to actual needs to achieve the best hydrogen supply and recovery effects.

[0080] Figure 15Shown is a schematic diagram of the hydrogen supply system structure of a multi-hydrogen supply sub-module. In the state where the required power of the load module is low, the control unit can choose to use a single bionic ejector as the circulation device. It is possible to use only the hydrogen fuel cell ejector 41 as the circulation device, open the solenoid valves 311, 315, 316, 318, 319, 321, and close the solenoid valves 312, 313, 314, 317, 320, 322. Another solution is to use only the hydrogen fuel cell ejector 42 as the circulation device. At this time, open the solenoid valves 312, 314, 318, 319, 321, and close the solenoid valves 311, 313, 315, 316, 317, 320, 322. Or choose the hydrogen fuel cell 43 or 44 as the circulation device. The nozzle structures of these four ejectors are different, and the hydrogen supply flow rate and entrainment coefficient brought under the same pressure are also different. Therefore, when selecting, it is necessary to select the appropriate ejector structure size according to specific requirements.

[0081] When the required power of the load is in an increasing state and the hydrogen supply demand increases from low to high, multiple ejectors are gradually used in parallel for hydrogen supply, and any two of the hydrogen fuel cell ejectors 41, 42, 43, 44 are taken for parallel processing. For example, when the hydrogen fuel cell ejector 41 and the hydrogen fuel cell ejector 42 are in parallel mode, open the solenoid valves 311, 312, 314, 315, 316, 318, 319, 321, 322, and close the solenoid valves 313, 317, 320, 322. However, as the hydrogen supply amount increases, the unreacted hydrogen also gradually increases. It is possible to additionally use a hydrogen fuel cell ejector in series for recovery. For example, while using the hydrogen fuel cell ejectors 41 and 42 in parallel, connect the hydrogen fuel cell ejector 43 or the hydrogen fuel cell ejector 44 in series, open the solenoid valves 311, 312, 314, 315, 316, 317, 321, and close the solenoid valves 313, 318, 319, 320, 322.

[0082] When the required power of the load continues to increase, the hydrogen fuel cell ejectors 41, 42, 43, 44 can be used in parallel, open the solenoid valves 311, 312, 314, 315, 316, 317, 318, 320, 321, 322, and close the solenoid valve 313, 319.

[0083] When the load needs to drop from a large required power to a small required power in a very short time, the hydrogen fuel cell ejectors 41, 42, 43, 44 are connected in series, open the solenoid valves 311, 313, 314, 316, 317, 319, 320, 322, and close the solenoid valves 312, 315, 318, 321, to quickly recover the unreacted hydrogen at the large required power.

[0084] For more flexible changes, more hydrogen fuel cell ejectors can be further connected in series or parallel, so that it can not only meet the demand for high hydrogen supply flow, but also recover more unreacted hydrogen, improving the energy utilization rate. By changing the different combination states of multiple ejectors in the hydrogen supply system, the hydrogen supply system can flexibly switch between low flow and high flow to meet different load demands, while increasing the recovery rate of unreacted hydrogen.

[0085] The combination mode can freely select the solenoid valve switch state according to actual needs to adapt to different hydrogen supply demands. For example, the solenoid valve switch state of a single ejector or the solenoid valve switch state of multiple ejectors connected in parallel can be adopted. At the same time, an appropriate bionic ejector can also be selected according to the demand for hydrogen supply volume and the recovery of unreacted hydrogen.

[0086] The control unit outputs a power status monitor through a communication connection, and receives the required power information of the load module in real time, and accordingly adjusts the state of the solenoid valve to ensure that the system can operate efficiently under different working conditions.

[0087] An embodiment of this application also proposes a control method for a fuel cell hydrogen supply system. This method is applied to the above hydrogen supply system, and this method includes:

[0088] Step S1, the load module 8 obtains the required power demand;

[0089] Step S2, the output power status monitor 9 monitors the required power of the load module 8 in real time and transmits it to the control unit 10;

[0090] Step S3, after the control unit 10 receives the signal of the required power, it judges the required power and the set hydrogen supply volume range, and matches the hydrogen supply mode corresponding to the hydrogen supply demand by controlling the opening and closing of the solenoid valve in real time; wherein the corresponding hydrogen supply mode is composed of multiple combination modes of different hydrogen fuel cell ejectors using "single, series, parallel" connections and their pairwise combinations;

[0091] Step S4, when the required power of the load module 8 changes, repeat steps S1 - S3, and adjust the solenoid valve in real time to control different hydrogen supply modes, so that the hydrogen supply system can switch between different flows, meet the required power of different loads, and at the same time increase the recovery rate of unreacted hydrogen.

[0092] This control method realizes the dynamic matching of the hydrogen supply flow rate and the load power of the fuel cell system through the intelligent combination and parameter optimization of multi-stage bionic ejectors. First, the demand power is obtained in real time through the load module, and the hydrogen supply amount range is set accordingly. The control unit dynamically switches the hydrogen supply mode of the solenoid valve group in real time: the single ejector low-pressure mode is adopted at low power, the parallel ejectors are enabled at medium and high power to enhance the mixing effect, and the multi-ejector parallel mode is switched at high power to superimpose the hydrogen supply flow rate. When changing from high power to low power, an additional series ejector is used to enhance the recovery effect, and each mode is matched with specific bionic parameters.

[0093] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0094] First, by changing the structural parameters such as the number of teeth, tooth length, tooth height, tooth width, and angle, the contradiction between the hydrogen supply flow rate and the entrainment coefficient caused by changing the nozzle shape is solved.

[0095] Second, different structural dimensions are adopted according to different working conditions to adapt to the hydrogen supply flow rate under the corresponding working conditions and improve its entrainment coefficient.

[0096] Third, using these multiple bionic ejectors to form different modes of single, series, parallel, and their combinations of two enables the hydrogen supply flow rate to adapt to the changing needs of the fuel cell stack, adapt to smoother regulation, maintain the high-efficiency and stable operation efficiency of the fuel cell, increase the hydrogen recirculation rate, and improve the energy utilization rate.

[0097] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A fuel cell multi-stage ejector, characterized in that, Comprising: A nozzle (12), a diffuser section (15), a suction chamber (13), a mixing chamber (17), and a diffuser chamber (18). The suction chamber (13) is arranged outside the diffuser section (15), and an ejector fluid channel (14) is arranged on the outer side of the suction chamber (13). The suction chamber (13), the mixing chamber (17), and the diffuser chamber (18) are connected in sequence. The front end of the nozzle (12) extends out of the suction chamber (13), the rear end of the nozzle (12) is connected to the inlet of the diffuser section (15), and a bionic ejector serration (16) is arranged on the inner side at the outlet of the diffuser section (15).

2. The fuel cell multi-stage ejector according to claim 1, wherein The diffuser section (15) includes a tapered section and a straight tube section. The top of the tapered section is connected to the rear end of the nozzle (12), and the bottom of the tapered section is connected to one end of the straight tube section.

3. The fuel cell multi-stage ejector according to claim 1, wherein The tooth number ratio range of the bionic ejector serration (16) is 0 - 0.

4.

4. The fuel cell multi-stage ejector according to claim 1, wherein The tooth length ratio range of the bionic ejector serration (16) is 0 - 0.

6.

5. The fuel cell multi-stage ejector according to claim 1, characterized in that, The tooth width ratio range of the bionic ejector serration (16) is 0 - 0.

4.

6. The fuel cell multi-stage ejector according to claim 1, characterized in that The tooth height ratio range of the bionic ejector serration (16) is 0 - 0.

6.

7. The fuel cell multi-stage ejector according to claim 1, characterized in that, The tooth angle of the bionic ejector serration (16) is selected according to the inlet pressure.

8. A hydrogen supply system, characterized in that, Comprising a hydrogen storage tank (1), a pressure reducing valve (2), a hydrogen supply regulation module, a fuel cell stack (5), a gas-liquid separator (6), a drain valve (7), a load module (8), an output power status monitor (9), and a control unit (10). The hydrogen storage tank (1), the pressure reducing valve (2), the hydrogen supply regulation module, the gas-liquid separator (6), and the drain valve (7) are connected in sequence. The hydrogen supply regulation module, the control unit (10), the output power status monitor (9), the fuel cell stack (5), and the load module (8) are connected in sequence. The hydrogen supply regulation module includes a plurality of hydrogen supply regulation sub-modules. Each hydrogen supply regulation sub-module includes a plurality of solenoid valves and a hydrogen fuel cell ejector according to any one of claims 1 - 8.

9. The hydrogen supply system according to claim 8, characterized in that, The hydrogen supply regulation sub-module is used to form a variety of hydrogen supply modes by precisely controlling the solenoid valves so that a plurality of hydrogen fuel cell ejectors are combined. The hydrogen supply modes include hydrogen bypassing the hydrogen fuel cell ejector and being directly transported, hydrogen flowing through each hydrogen fuel cell ejector independently, hydrogen passing through a plurality of hydrogen fuel cell ejectors in sequence to achieve cascade supply, and hydrogen being synchronously distributed to a plurality of hydrogen fuel cell ejectors to form coordinated supply.

10. A hydrogen supply system control method, characterized in that, The method is applied to the hydrogen supply system according to claim 8 or 9, and the method includes: Step S1, the load module (8) obtains the required demand power. Step S2, the output power status monitor (9) monitors the demand power of the load module (8) in real time and transmits it to the control unit (10). Step S3, after the control unit (10) receives the signal of the demand power, it judges the required demand power and the set hydrogen supply amount range, and matches the hydrogen supply mode corresponding to the hydrogen supply amount demand by controlling the opening and closing of the solenoid valve in real time. The corresponding hydrogen supply mode is composed of various combination modes of "series, parallel, and single" connection and their pairwise combinations of different hydrogen fuel cell ejectors. Step S4: When the required power of the load module (8) changes, repeat Steps S1 - S3 to adjust the solenoid valve in real time to control different hydrogen supply modes, enabling the hydrogen supply system to switch between different flow rates, meet the required power of different loads, and at the same time increase the recovery rate of unreacted hydrogen.

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