Efficient fuel cell energy recovery device and control method

Abstract

The invention provides an efficient fuel cell energy recovery device and a control method. The device comprises an air inlet control module, an air inlet heat management module, a hydrogen inlet module and an energy recovery module, the air inlet control module is connected with the energy recovery module, the energy recovery module is connected with a galvanic pile through the air inlet heat management module, the hydrogen inlet module is connected with the galvanic pile, and the galvanic pile is connected with the energy recovery module to form a loop. The energy recovery module includes a hybrid expander. Waste gas energy generated by the fuel cell can be utilized to the maximum extent, the parasitic power of the fuel cell system is reduced, and the output power of the fuel cell system is improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell technology, and in particular to a high-efficiency fuel cell energy recovery device and a control method. Background Art

[0002] With the rapid development of urbanization and industrialization, my country's demand for various energy resources is increasing, especially the increasing dependence on electric energy, and new energy related industries are also developing rapidly. Hydrogen fuel cells are a power generation device that directly converts chemical energy into electrical energy. The actual operation of the hydrogen fuel cell system is to transport compressed air and high-pressure hydrogen in the hydrogen bottle to the fuel cell stack through an air compressor to generate electricity. The electricity is used to drive electrical equipment, while the compressed air and high-pressure hydrogen that do not participate in the reaction are discharged into the atmosphere as waste gas. Parasitic power is generated during the operation of the hydrogen fuel cell system. The main parasitic power is caused by the air compressor that provides intake power for the reactants, which reduces the output power of the hydrogen fuel cell system. How to improve the output power of the hydrogen fuel cell system and how to reduce the power consumption of the air compressor have also become the main difficulties to be overcome in the industry.

[0003] As a core component, the air compressor of the hydrogen fuel cell system provides intake power for the fuel cell stack reaction gas. It needs to meet the requirements of high pressure, large flow and rapid response to pressure and flow changes. Therefore, the air compressor needs to provide a higher speed and faster response capability, and needs a larger power drive. This part of power accounts for more than 90% of the total parasitic power of the hydrogen fuel cell system. Therefore, reducing the power consumption of the air compressor has become the top priority in improving the output efficiency of the system. The current main technical route is expander technology, which recovers energy from the exhaust gas discharged from the cathode. The gas discharged from the cathode is a high-temperature and high-pressure gas that does not require secondary work. It enters the vortex end of the expander to generate kinetic energy, reduce the power of the air compressor motor, reduce the parasitic power of the system, and thus improve the output efficiency of the fuel cell system.

[0004] However, in addition to exhaust gas generated on the cathode side, the fuel cell system also generates high-temperature and high-pressure exhaust gas on the anode side. Usually, the exhaust gas pressure on the anode side is higher than the exhaust gas pressure on the cathode side, and the temperatures of the two are basically the same. Therefore, recovering the energy of the anode exhaust gas will be more helpful in reducing the power of the air compressor.

[0005] Currently, the existing technical methods only recover the exhaust gas energy generated on the cathode side or the anode exhaust gas energy alone, and do not recover the exhaust gas energy of both the cathode and anode at the same time. The original technology has a low exhaust gas energy recovery rate, does not control the air compressor motor power in real time, has no obvious effect on improving the overall output power of the fuel cell system, and cannot maximize the use of exhaust gas energy.

[0006] The present invention is based on the expander technology route, which recovers the cathode and anode exhaust gas energy at the same time, maximizes the utilization of the energy generated by the exhaust gas, and controls the impeller angle according to the different exhaust gas energies generated under different working conditions, so that the utilization efficiency of the expander reaches the optimal state. Summary of the invention

[0007] According to the above-mentioned technical problem that the existing fuel cells have insufficient energy recovery efficiency and cannot effectively reduce the parasitic power of the fuel cell system, a high-efficiency fuel cell energy recovery device and control method are provided. The present invention mainly generates exhaust gas at the cathode outlet and the anode outlet at the same time when the fuel cell is running, recovers the energy of the high-temperature and high-pressure gas discharged from the cathode and the anode, calibrates the air compressor motor power and VNT angle curve under different working conditions, forms a database, monitors the power consumption change of the air compressor in real time, adjusts the VNT angle in real time, controls the recovery efficiency of the expander vortex end, and then improves the electrical efficiency of the expander as a whole, and finally reduces the parasitic power of the fuel cell system and improves the output power of the fuel cell system.

[0008] The technical means adopted by the present invention are as follows:

[0009] A high-efficiency fuel cell energy recovery device, comprising: an air intake control module, an air intake thermal management module, a hydrogen intake module and an energy recovery module, wherein the air intake control module is connected to the energy recovery module, the energy recovery module is connected to the fuel cell stack through the air intake thermal management module, the hydrogen intake module is connected to the fuel cell stack, the fuel cell stack is connected to the energy recovery module to form a loop, and the energy recovery module comprises a hybrid expander;

[0010] The air intake control module is used to transport external air to the hybrid expander, and the hybrid expander is used to generate high-temperature and high-pressure air, and the high-temperature and high-pressure air is transported to the fuel cell stack through the air intake thermal management module for chemical reaction; the air that does not participate in the reaction is transported from the fuel cell stack to the energy recovery module to generate compressed gas, and the compressed gas is transmitted to the hybrid expander, and the air exhaust gas after passing through the energy recovery module is discharged into the atmosphere;

[0011] The hydrogen intake module is used to transport high-pressure hydrogen to the fuel cell stack for chemical reaction. The hydrogen that does not participate in the reaction is transported from the fuel cell stack to the energy recovery module to generate compressed gas. The compressed gas is transmitted to the hybrid expander. The hydrogen exhaust gas after passing through the energy recovery module is mixed with new hydrogen and enters the fuel cell stack again.

[0012] Further, the energy recovery module includes a hybrid expander, an air water separator, a hydrogen water separator, a hydrogen exhaust valve and a VNT, the hybrid expander includes an air exhaust turbocharger, a hydrogen exhaust turbocharger, an air compressor and an air compressor motor, and the VNT includes VNT1 and VNT2;

[0013] The fuel cell stack is connected to the air exhaust gas turbocharger through an air water separator, the fuel cell stack is connected to the hydrogen exhaust gas turbocharger through a hydrogen water separator, the hydrogen water separator is connected to the hydrogen exhaust valve, the air exhaust gas turbocharger and the hydrogen exhaust gas turbocharger are both connected to the air compressor, the air compressor is connected to the air compressor motor, the VNT1 is connected to the hydrogen exhaust gas turbocharger, and the VNT2 is connected to the air exhaust gas turbocharger.

[0014] Furthermore, the air intake control module includes a back pressure valve, a muffler and an air filter, the air filter is connected to the hybrid expander, the muffler is connected to the back pressure valve, the back pressure valve is connected to the air exhaust turbocharger, and the air water separator is connected to the pipeline between the muffler and the back pressure valve through a pipeline.

[0015] Furthermore, the air intake thermal management module includes a fin-type water-cooled intercooler, and the intercooler is connected to the hybrid expander and the fuel cell stack.

[0016] Furthermore, the hydrogen intake module comprises an intake solenoid valve, an ejector and a proportional valve which are connected in sequence, the ejector is connected to a hydrogen exhaust gas turbocharger, and the proportional valve is connected to the fuel cell stack.

[0017] Furthermore, the air compressor motor is connected to a motor voltage sensor and a motor current sensor, the VNT1 is connected to a VNT1 angle sensor, and the VNT2 is connected to a VNT2 angle sensor.

[0018] Furthermore, an air flow meter sensor is provided between the air filter and the hybrid expander.

[0019] Furthermore, an air-inlet pressure sensor and an air-inlet temperature sensor are installed between the intercooler and the fuel cell stack.

[0020] Furthermore, a hydrogen inlet pressure sensor and a hydrogen inlet temperature sensor are installed between the ejector and the proportional valve.

[0021] The present invention also provides a control method for a high-efficiency fuel cell energy recovery device, comprising the following steps:

[0022] The outside air is filtered through the air filter to remove harmful impurities in the air, and then enters the air compressor for air compression, generating high-temperature and high-pressure air that enters the intercooler. The intercooler cools the high-temperature gas to the target temperature. The cooled reaction air enters the fuel cell stack for chemical reaction to generate electricity. The air that does not participate in the reaction is discharged through the air outlet of the fuel cell stack. The air is in a gas-liquid mixed state and contains a large amount of liquid water. The air is separated by the air water separator. The separated air enters the air exhaust turbocharger of the hybrid expander. The air exhaust drives the impeller to rotate and generates compressed gas. The gas is transmitted to the air compressor as pre-compressed gas, so that the air intake of the air compressor has a certain kinetic energy, thereby reducing the power consumption of the air compressor. The air exhaust after passing through the air exhaust turbocharger is discharged into the atmosphere through the muffler.

[0023] At the same time, the corresponding reaction process is also carried out on the hydrogen side. The high-pressure hydrogen enters the fuel cell through the hydrogen solenoid valve and the proportional valve to undergo chemical reactions and generate electrical energy. The hydrogen that does not participate in the reaction is discharged through the fuel cell hydrogen outlet. The hydrogen is in a gas-liquid mixed state and is separated by the hydrogen water separator. After separation, the hydrogen enters the hydrogen exhaust gas turbocharger of the hybrid expander. The hydrogen exhaust drives the impeller to rotate and generates compressed gas. The gas is transmitted to the air compressor as pre-compressed gas, so that the air intake of the air compressor has a certain kinetic energy, thereby reducing the power consumption of the air compressor. The hydrogen exhaust after passing through the hydrogen exhaust gas turbocharger enters the hydrogen ejector, mixes with new hydrogen and enters the fuel cell again.

[0024] At the same time, when operating under different working conditions, the air compressor motor power and VNT angle curves under different working conditions are calibrated to form a database, and the current air compressor motor power changes and air compressor power consumption changes are monitored in real time. The exhaust turbine blade angles of the cathode and anode are adjusted in real time, and the air compressor motor power is adjusted in real time to maximize the exhaust gas energy utilization rate. By simultaneously recovering energy at the cathode and anode and monitoring the air compressor power in real time, the fuel cell exhaust gas energy is fully utilized, which greatly reduces the air compressor motor power consumption and improves the output efficiency of the fuel cell system.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The present invention provides a high-efficiency fuel cell energy recovery device and control method, which can reduce the power consumption of the air compressor motor by recovering the energy generated by the cathode and anode exhaust gas in real time online, recover the energy of the exhaust gas at the cathode outlet of the stack, and recover the energy of the exhaust gas at the anode outlet of the stack at the same time. During the operation of the stack, the cathode and anode simultaneously generate exhaust gas, and the pressure of the exhaust gas generated by the anode is also higher than the pressure of the cathode exhaust gas, so the recovered energy is greater. The exhaust gas at the cathode outlet of the stack enters the air exhaust gas turbocharger for energy recovery after passing through the air water separator, and the exhaust gas at the anode outlet enters the hydrogen exhaust gas turbocharger for energy recovery through the hydrogen water separator. The energy recovered by the two at the same time acts together with the air compressor motor, greatly reducing the power of the air compressor motor. In addition, by calibrating the VNT opening and motor power curves under different working conditions, a database is formed. During the actual operation, the air compressor motor power curve is offset from the database curve, and the VNT angle is adjusted in real time to keep the air compressor motor power in the optimal state at all times, and the exhaust gas energy utilization rate is maximized. After simultaneously recovering the energy of the cathode and anode, the fuel cell exhaust gas energy is fully utilized, greatly reducing the power consumption of the air compressor motor, and improving the output efficiency of the fuel cell system.

[0027] Based on the above reasons, the present invention can be widely promoted in the fields of fuel cells and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0029] Figure 1 It is a schematic diagram of the fuel electric energy recovery control device (different axes) of the present invention.

[0030] Figure 2 It is a schematic diagram of the fuel electric energy recovery control device (coaxial) of the present invention.

[0031] Figure 3 This is a flow chart of waste gas energy recovery according to the present invention.

[0032] Figure 4 It is a schematic diagram of the angle changes of VNT1 and VNT2 at different working points of the present invention.

[0033] Figure 5 This is a power comparison chart of an air compressor without expander, an air expander compressor, and a hybrid expander compressor at different operating points of the present invention.

[0034] In the figure: 1. Intake solenoid valve; 2. Ejector; 3. Hydrogen inlet pressure sensor; 4. Hydrogen inlet temperature sensor; 5. Proportional valve; 6. Fuel cell; 7. Air inlet pressure sensor; 8. Air inlet temperature sensor; 9. Intercooler; 10. Air water separator; 11. VNT1 angle sensor; 12. VNT2 angle sensor; 13. VNT1; 14. VNT2; 15. Back pressure valve; 16. Muffler; 17. Air filter; 18. Air flow meter sensor; 19. Hybrid expander; 20. Air exhaust turbocharger; 21. Hydrogen exhaust turbocharger; 22. Air compressor; 23. Motor voltage sensor; 24. Air compressor motor; 25. Motor current sensor; 26. Hydrogen water separator; 27. Hydrogen exhaust valve. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0039] Example 1

[0040] At present, the expander structure of the fuel cell system is mainly composed of an air compressor (motor + impeller) and an air exhaust gas turbocharger. The energy recovery method is mainly through the gas from the cathode outlet of the fuel cell entering the air exhaust gas turbocharger at the turbine end of the expander, and the pressure and temperature of the exhaust gas generate energy for secondary utilization, thereby reducing the power consumption of the compressor motor and thus reducing the overall power of the expander. The current technology is limited to energy recovery on the cathode side, and the energy on the anode side is not used at the same time. There is no real-time control of the power consumption of the air compressor motor, and the waste gas resources are not maximized for conversion into energy.

[0041] In view of the fact that the energy recovery efficiency of existing fuel cells is insufficient and the parasitic power of the fuel cell system cannot be effectively reduced, the present invention provides a high-efficiency fuel cell energy recovery device and a control method.

[0042] The fuel cell energy recovery device constructed by the present invention includes an air intake control module, an air intake thermal management module, a hydrogen intake module, an energy recovery module and a data acquisition module. The air intake control module, the air intake thermal management module, the hydrogen intake module and the energy recovery module are all connected to the data acquisition module. The air intake control module is connected to the energy recovery module. The energy recovery module is connected to the fuel cell stack through the air intake thermal management module. The hydrogen intake module is connected to the fuel cell stack. The fuel cell stack is connected to the energy recovery module to form a loop. By controlling the energy recovery module, the cathode and anode exhaust gases are energy recovered, the air compressor motor power can be monitored and controlled in real time, and the cathode and anode exhaust gas turbocharger blade angles can be adjusted in real time to keep the air compressor motor power in an optimal state. The exhaust gas energy generated by the fuel cell can be utilized to the greatest extent, the parasitic power of the fuel cell system can be reduced, and the output power of the fuel cell system can be improved. Figure 1 , Figure 2 As shown, the present invention is applicable to energy recovery of coaxial and non-coaxial air compressor expanders and hydrogen expanders.

[0043] Among them, the air intake control module is composed of an air filter 17 (air filter), a back pressure valve 15, and a muffler 16. The air intake thermal management module is composed of a fin-type water-cooled intercooler 9. The hydrogen intake module is composed of a hydrogen valve group, which includes an intake solenoid valve 1, an ejector 2, and a proportional valve 5. The energy recovery module is composed of a hybrid expander 19, an air water separator 10, a hydrogen water separator 26, a hydrogen exhaust valve 27, and a VNT. The hybrid expander 19 includes an air exhaust turbocharger 20, a hydrogen exhaust turbocharger 21, an air compressor 22, and an air compressor motor 24. The VNT includes VNT113 and VNT214. Data acquisition module: It is composed of air pressure sensor 7, air temperature sensor 8, air flow meter sensor 18, hydrogen inlet pressure sensor 3, hydrogen inlet temperature sensor 4, motor current sensor 25, motor voltage sensor 23, VNT1 angle sensor 11, and VNT2 angle sensor 12.

[0044] The intake solenoid valve 1, the ejector 2, and the proportional valve 5 are connected in sequence through pipelines. The hydrogen inlet pressure sensor 3 and the hydrogen inlet temperature sensor 4 are installed in sequence on the pipeline between the ejector 2 and the proportional valve 5. The proportional valve 5 is connected to the fuel cell stack 6, and the fuel cell stack 6 is connected to the intercooler 9, the air water separator 10, and the hydrogen water separator 26.

[0045] The intercooler 9 is connected to the air compressor 22 of the hybrid expander 19 , and an air inlet pressure sensor 7 and an air inlet temperature sensor 8 are installed on the pipeline between the intercooler 9 and the fuel cell stack 6 .

[0046] The air water separator 10 is connected to an air-exhaust gas turbocharger 20 of a hybrid expander 19 .

[0047] The hydrogen water separator 26 is connected to the hydrogen exhaust gas turbocharger 21 of the hybrid expander 19 , and the hydrogen exhaust and water discharge valve 27 is connected to the hydrogen water separator 26 .

[0048] The air filter 17 is connected to the hybrid expander, and the air flow meter sensor 18 is installed between the air filter 17 and the hybrid expander 19.

[0049] The muffler 16 is connected to the back pressure valve 15 , the back pressure valve 15 is connected to the air exhaust turbocharger 20 , and the air water separator 10 is also connected to the pipeline between the muffler 16 and the back pressure valve 15 through a pipeline.

[0050] The air exhaust gas turbocharger 20 and the hydrogen exhaust gas turbocharger 21 are both connected to the air compressor 22, the air compressor motor 24 is connected to the air compressor 22, and the motor current sensor 25 and the motor voltage sensor 23 are both connected to the air compressor motor 24. VNT113 is connected to the hydrogen exhaust gas turbocharger 21, VNT214 is connected to the air exhaust gas turbocharger 20, the VNT1 angle sensor 11 is connected to VNT113, and the VNT2 angle sensor 12 is connected to VNT214.

[0051] Example 2

[0052] Based on Example 1, the present invention further provides a control method for a high-efficiency fuel cell energy recovery device, comprising:

[0053] When the fuel cell is running, exhaust gas is generated at the cathode outlet and the anode outlet at the same time, and the high-temperature and high-pressure gases discharged from the cathode and the anode are used for energy recovery (the exhaust gas at the cathode outlet enters the air exhaust turbocharger, and the exhaust gas at the anode outlet enters the hydrogen exhaust turbocharger). The air compressor motor power and VNT angle curves under different working conditions are calibrated (according to different working conditions, the VNT2 angle is calibrated to recover the cathode exhaust gas energy; according to different working conditions, the VNT1 angle is calibrated to recover the anode exhaust gas energy). A database is formed to monitor the changes in the power consumption of the air compressor in real time, adjust the VNT angle in real time, control the recovery efficiency of the expander turbine end, and thereby improve the electrical efficiency of the expander as a whole, ultimately reducing the parasitic power of the fuel cell system and improving the output power of the fuel cell system.

[0054] The specific steps include:

[0055] The outside air is filtered through the air filter 17 to remove harmful impurities in the air, and enters the air compressor 22 for air compression, generating high-temperature and high-pressure air that enters the intercooler 9. The intercooler 9 cools the high-temperature gas to the target temperature. The cooled reaction air enters the fuel cell stack 6 for chemical reaction to generate electrical energy. The air that does not participate in the reaction is discharged through the air outlet of the fuel cell stack 6. The air is in a gas-liquid mixed state and contains a large amount of liquid water. The air is separated by the air water separator 10. The separated air enters the air exhaust gas turbocharger 20 of the hybrid expander 19. The air exhaust gas drives the impeller to rotate to generate compressed gas. The gas is transmitted to the air compressor 22 as pre-compressed gas, so that the air intake of the air compressor 22 has a certain kinetic energy, thereby reducing the power consumption of the air compressor 22. The air exhaust gas after passing through the air exhaust gas turbocharger 20 is discharged into the atmosphere through the muffler 16. At the same time, the corresponding reaction process is also carried out on the hydrogen side. The high-pressure hydrogen enters the fuel cell 6 through the hydrogen solenoid valve 1 and the proportional valve 5 to undergo a chemical reaction to generate electrical energy. The hydrogen that does not participate in the reaction is discharged through the hydrogen outlet of the fuel cell 6. The hydrogen is in a gas-liquid mixed state and is separated by the hydrogen water separator 26. After separation, the hydrogen enters the hydrogen exhaust gas turbocharger 21 of the hybrid expander 19. The hydrogen exhaust drives the impeller to rotate to generate compressed gas. The gas is transmitted to the air compressor 22 as pre-compressed gas, so that the air intake of the air compressor 22 has a certain kinetic energy, thereby reducing the power of the air compressor 22. The hydrogen exhaust gas after the hydrogen exhaust turbocharger 21 enters the hydrogen ejector 2, is mixed with new hydrogen and enters the fuel cell stack 6 again. At the same time, when operating under different working conditions, the current air compressor motor power change can be monitored in real time, the exhaust turbine blade angles of the cathode and anode can be adjusted in real time, and the air compressor motor power can be adjusted in real time to maximize the exhaust gas energy utilization rate. By simultaneously recovering the energy of the cathode and anode and monitoring the air compressor power in real time, the fuel cell exhaust gas energy can be fully utilized, the air compressor motor power consumption can be greatly reduced, and the output efficiency of the fuel cell system can be improved.

[0056] The original energy recovery technology only recovers energy by allowing the gas discharged from the cathode outlet of the fuel cell stack to enter the expander exhaust gas turbocharger, and the recovered energy is applied to the air compressor motor to reduce the power consumption of the air compressor motor, but the anode exhaust gas energy is not recovered at the same time.

[0057] The device of the present invention reduces the power consumption of the air compressor motor by recovering the energy generated by the cathode and anode exhaust gases in real time online. While recovering the exhaust gas energy at the cathode outlet of the battery stack, the exhaust gas energy at the anode outlet of the battery stack is also recovered simultaneously. During the operation of the battery stack, the cathode and anode simultaneously generate exhaust gas, and the pressure of the exhaust gas generated by the anode is also higher than the pressure of the cathode exhaust gas, so the recovered energy is greater. The exhaust gas at the cathode outlet of the battery stack enters the air exhaust gas turbocharger for energy recovery after passing through an air water separator, and the exhaust gas at the anode outlet enters the hydrogen exhaust gas turbocharger for energy recovery through a hydrogen water separator. The energy recovered by the two at the same time acts together with the air compressor motor, greatly reducing the power of the air compressor motor. In addition, when operating under different working conditions, the current air compressor motor power can be monitored and controlled in real time, compared with the data in the calibrated database, and the exhaust turbine blade angles of the cathode and anode can be corrected in real time to adjust the air compressor motor power in real time. By calibrating the VNT opening and motor power curve under different working conditions, a database is formed. During actual operation, the air compressor motor power curve is offset from the database curve, and the VNT angle is adjusted in real time to keep the air compressor motor power at the optimal state at all times, maximizing the exhaust gas energy utilization rate. By simultaneously recovering energy from the cathode and anode and controlling the air compressor power in real time, the exhaust gas energy of the fuel cell is fully utilized, which greatly reduces the power consumption of the air compressor motor and improves the output efficiency of the fuel cell system.

[0058] The changes in VNT angle under different working conditions and the power comparison of the air compressor without expander, air expander air compressor and hybrid expander air compressor under the same working conditions are as follows Figure 4 , Figure 5 shown.

[0059] Figure 4 It shows that under different working conditions, the VNT angle does not remain unchanged, but the opening angles of VNT1 and VNT2 change in real time according to the changes in working conditions, so that the turbocharger can perform at its optimal state.

[0060] Figure 5 It shows the comparison of power consumption of expander-free air compressor, air expander air compressor and hybrid expander air compressor under the same working conditions. It is obvious that under various working conditions, the power consumption is from large to small: expander-free air compressor power > air expander air compressor power > hybrid expander air compressor power. Compared with the air expander with original energy recovery technology, the power consumption of the hybrid expander is reduced by up to 24%.

[0061] The invention provides a high-efficiency fuel cell energy recovery device and control method, which are characterized by:

[0062] 1. The present invention can simultaneously recover the energy of cathode and anode exhaust gases;

[0063] 2. The present invention is applicable to energy recovery of coaxial and non-coaxial air compressor expanders and hydrogen expanders;

[0064] 3. The present invention can monitor and control the power consumption of the air compressor motor in real time, and correct the impeller angles of the cathode and anode exhaust gas turbochargers in real time;

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-efficiency fuel cell energy recovery device, characterized in that: include: An air intake control module, an air intake thermal management module, a hydrogen intake module and an energy recovery module, wherein the air intake control module is connected to the energy recovery module, the energy recovery module is connected to the fuel cell stack (6) via the air intake thermal management module, the hydrogen intake module is connected to the fuel cell stack (6), the fuel cell stack (6) is connected to the energy recovery module to form a loop, and the energy recovery module includes a hybrid expander (19); The air intake control module is used to transport external air to the hybrid expander (19), and the hybrid expander (19) is used to generate high-temperature and high-pressure air, and the high-temperature and high-pressure air is transported to the fuel cell stack (6) through the air intake thermal management module for chemical reaction; the air that does not participate in the reaction is transported from the fuel cell stack (6) to the energy recovery module to generate compressed gas, and the compressed gas is transmitted to the hybrid expander (19), and the air exhaust gas after passing through the energy recovery module is discharged into the atmosphere; The hydrogen intake module is used to transport high-pressure hydrogen to the fuel cell stack (6) for chemical reaction. The hydrogen that does not participate in the reaction is transported from the fuel cell stack (6) to the energy recovery module to generate compressed gas. The compressed gas is transmitted to the hybrid expander (19). The hydrogen waste gas after passing through the energy recovery module is mixed with new hydrogen and enters the fuel cell stack (6) again.

2. The high-efficiency fuel cell energy recovery device according to claim 1, characterized in that: The energy recovery module comprises a hybrid expander (19), an air water separator (10), a hydrogen water separator (26), a hydrogen exhaust valve (27) and a VNT, the hybrid expander (19) comprises an air exhaust turbocharger (20), a hydrogen exhaust turbocharger (21), an air compressor (22) and an air compressor motor (24), and the VNT comprises a VNT1 (13) and a VNT2 (14); The fuel cell stack (6) is connected to an air exhaust gas turbocharger (20) via an air water separator (10), the fuel cell stack (6) is connected to a hydrogen exhaust gas turbocharger (21) via a hydrogen water separator (26), the hydrogen water separator (26) is connected to a hydrogen exhaust valve (27), the air exhaust gas turbocharger (20) and the hydrogen exhaust gas turbocharger (21) are both connected to an air compressor (22), the air compressor (22) is connected to an air compressor motor (24), the VNT1 (13) is connected to the hydrogen exhaust gas turbocharger (21), and the VNT2 (14) is connected to the air exhaust gas turbocharger (20).

3. The high-efficiency fuel cell energy recovery device according to claim 2, characterized in that: The air intake control module comprises a back pressure valve (15), a muffler (16) and an air filter (17), wherein the air filter (17) is connected to a hybrid expander (19), the muffler (16) is connected to the back pressure valve (15), the back pressure valve (15) is connected to an air exhaust turbocharger (20), and the air water separator (10) is connected to a pipeline between the muffler (16) and the back pressure valve (15) through a pipeline.

4. The high-efficiency fuel cell energy recovery device according to claim 2, characterized in that: The air intake thermal management module comprises a fin-type water-cooled intercooler (9), and the intercooler (9) is connected to a hybrid expander (19) and a fuel cell stack (6).

5. The high-efficiency fuel cell energy recovery device according to claim 2, characterized in that: The hydrogen intake module comprises an intake solenoid valve (1), an ejector (2) and a proportional valve (5) which are connected in sequence, the ejector (2) being connected to a hydrogen exhaust gas turbocharger (21), and the proportional valve (5) being connected to a fuel cell stack (6).

6. The high-efficiency fuel cell energy recovery device according to claim 2, characterized in that: The air compressor motor (24) is connected to a motor voltage sensor (23) and a motor current sensor (25), the VNT1 (13) is connected to a VNT1 angle sensor (11), and the VNT2 (14) is connected to a VNT2 angle sensor (12).

7. The high-efficiency fuel cell energy recovery device according to claim 3, characterized in that: An air flow meter sensor (18) is provided between the air filter (17) and the hybrid expander (19).

8. The high-efficiency fuel cell energy recovery device according to claim 4, characterized in that: An air-in pressure sensor (7) and an air-in temperature sensor (8) are installed between the intercooler (9) and the fuel cell stack (6).

9. The high-efficiency fuel cell energy recovery device according to claim 5, characterized in that: A hydrogen inlet pressure sensor (3) and a hydrogen inlet temperature sensor (4) are installed between the ejector (2) and the proportional valve (5).

10. A control method for a high-efficiency fuel cell energy recovery device according to any one of claims 1 to 9, characterized in that: The steps include: The outside air is filtered through an air filter (17) to remove harmful impurities in the air, and then enters the air compressor (22) for air compression, generating high-temperature and high-pressure air that enters the intercooler (9). The intercooler (9) cools the high-temperature gas to a target temperature. The cooled reaction air enters the fuel cell stack (6) for chemical reaction to generate electrical energy. The air that does not participate in the reaction is discharged through the air outlet of the fuel cell stack (6). The air is in a gas-liquid mixed state and contains a large amount of liquid water. The air is separated by an air water separator (10). The separated air enters the air exhaust gas turbocharger (20) of the hybrid expander (19). The air exhaust gas drives the impeller to rotate to generate compressed gas. The gas is transmitted to the air compressor (22) as pre-compressed gas, so that the air intake of the air compressor (22) has a certain kinetic energy, thereby reducing the power consumption of the air compressor (22). The air exhaust gas after passing through the air exhaust gas turbocharger (20) is discharged to the atmosphere through a muffler (16); At the same time, the corresponding reaction process is also carried out on the hydrogen side. The high-pressure hydrogen enters the fuel cell (6) through the hydrogen solenoid valve (1) and the proportional valve (5) to undergo a chemical reaction to generate electrical energy. The hydrogen that does not participate in the reaction is discharged through the hydrogen outlet of the fuel cell (6). The hydrogen is in a gas-liquid mixed state and is separated by the hydrogen water separator (26). After separation, the hydrogen enters the hydrogen exhaust gas turbocharger (21) of the hybrid expander (19). The hydrogen exhaust drives the impeller to rotate to generate compressed gas. The gas is transmitted to the air compressor (22) as pre-compressed gas, so that the air intake of the air compressor (22) has a certain kinetic energy, thereby reducing the power consumption of the air compressor (22). The hydrogen exhaust after passing through the hydrogen exhaust gas turbocharger (21) enters the hydrogen ejector (2), is mixed with new hydrogen, and enters the fuel cell (6) again; At the same time, when operating under different working conditions, the power and VNT angle curves of the air compressor motor (24) under different working conditions are calibrated to form a database, and the current power changes of the air compressor motor (24) and the power consumption changes of the air compressor (22) are monitored in real time. The exhaust turbine blade angles of the cathode and anode are adjusted in real time, and the power of the air compressor motor (24) is adjusted in real time to maximize the utilization rate of the exhaust gas energy. By simultaneously recovering the energy of the cathode and anode and monitoring the air compressor power in real time, the exhaust gas energy of the fuel cell is fully utilized, the power consumption of the air compressor motor (24) is greatly reduced, and the output efficiency of the fuel cell system is improved.

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