Low-energy-consumption thermal management system and method for energy efficiency of hydrogen fuel stack

Abstract

The invention relates to the technical field of thermal management of fuel cells, and discloses a low-energy-consumption thermal management system and method for energy efficiency of a hydrogen fuel stack, and the system comprises a liquid hydrogen storage tank, a hydrogen generator, a waste heat and waste heat exchanger, an anode reactant pipeline, a fuel cell stack and a cathode reactant pipeline, according to the invention, the liquid hydrogen is used as a reactant and a coolant at the same time, thermal management is carried out on the hydrogen fuel cell stack through low-temperature hydrogen generated by heating the liquid hydrogen, and the generated hydrogen is directly used as a reactant to be fed into the anode of the stack, so that the system configuration of three loops of the traditional fuel stack is simplified; and the energy utilization efficiency of the hydrogen fuel cell is improved by utilizing the waste heat of the electric pile, and the energy consumption of the whole system is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell thermal management, and in particular to a thermal management system and method for improving the energy efficiency of a hydrogen fuel cell stack with low energy consumption. Background Art

[0002] Proton exchange membrane fuel cells are devices that convert chemical energy directly into electrical energy. They have the advantages of high efficiency, energy saving, environmental friendliness, and high reliability. During operation, fuel cells generate a large amount of heat energy. If it cannot be effectively removed, the service life of the fuel cell will be shortened. Therefore, it is necessary to implement an efficient thermal management strategy to regulate the temperature distribution of hydrogen fuel cells to ensure the safety and reliability of their operation.

[0003] Liquid hydrogen storage has a high volume energy density. The density of 70MPa high-pressure hydrogen is 39.062kg / m3, and the density of liquid hydrogen is 70kg / m3. Its volume energy density is about twice that of compressed hydrogen storage. Therefore, the coolant stored in liquid hydrogen has the advantages of small size and high cooling capacity, and is suitable for cooling high-mobility mobile hydrogen equipment. Liquid hydrogen can not only be used to cool battery components, but also as a fuel supply to achieve efficient energy utilization. It can not only reduce the volume and weight of the cooling system, but also improve the overall performance of hydrogen fuel cells. Therefore, a hydrogen fuel cell system that uses liquid hydrogen storage and appropriately heats the low-temperature hydrogen as a cooling medium is a potential research direction for rationally utilizing the heat generated by the hydrogen fuel cell stack to improve the thermal management efficiency of hydrogen fuel cells.

[0004] At present, most hydrogen fuel cell operating systems contain three circuits, a cooling circuit for the fuel cell stack, a cathode reactant gas circuit, and an anode reactant gas circuit. This method uses a cooling circuit to manage the heat of the fuel cell stack, passes the coolant into the stack for convection exchange to remove the heat, and the coolant that passes through the stack returns to the cooling circuit after heat dissipation for alternating use. This method does not make reasonable use of the waste heat of the fuel cell stack, and requires the design of an additional anode reactant gas circuit for reactant delivery.

[0005] Obviously, the current thermal management scheme of hydrogen fuel cells fails to effectively utilize the heat generated by the fuel cell stack and relies on an additional anode reactant delivery path, which leads to problems such as high energy consumption and low energy utilization efficiency during the thermal management process. Summary of the invention

[0006] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a low-energy consumption hydrogen fuel cell energy efficiency thermal management system and method to solve the technical problem in the prior art of how to reduce energy consumption in the thermal management process while improving energy utilization efficiency.

[0007] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a low-energy consumption hydrogen fuel cell energy efficiency thermal management system, including a liquid hydrogen storage tank, a hydrogen generator, a waste heat heat exchanger, an anode reactant pipeline, a fuel cell stack, and a cathode reactant pipeline; The fuel cell stack comprises a plurality of fuel cells stacked in sequence; each of the plurality of fuel cells is provided with an anode cooling pipeline, an anode reactant channel, a cathode reactant channel, a cathode cooling pipeline and an output port from top to bottom; The output end of the liquid hydrogen storage tank is provided with a branch line, one of which is connected to the input ends of the anode cooling pipeline and the cathode cooling pipeline of a plurality of fuel cells respectively after passing through the hydrogen generator; the other branch line is connected to the first input end of the waste heat heat exchanger; the output ends of the anode cooling pipeline and the cathode cooling pipeline of the plurality of fuel cells are connected to the second input end of the waste heat heat exchanger; The output end of the waste heat heat exchanger is connected to the input end of the anode reactant pipeline; the output end of the anode reactant pipeline is connected to the anode reactant channels of several fuel cells; the input end of the cathode reactant pipeline is used to input air, and the output end is connected to the cathode reactant channels of several fuel cells.

[0008] Preferably, the output end of the liquid hydrogen storage tank is provided with a hydrogen supply valve and a hydrogen pump in sequence along the hydrogen output direction.

[0009] Preferably, a first buffer tank and a first flow meter are sequentially provided between the hydrogen generator and the input ends of the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells along the direction of hydrogen output.

[0010] Preferably, the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells have the same structure, which includes a mesh cooling pipeline structure and a spiral cooling pipeline structure.

[0011] Preferably, a first temperature regulator is provided between the output ends of the anode cooling pipelines and the cathode cooling pipelines of the plurality of fuel cells and the second input end of the waste heat heat exchanger.

[0012] Preferably, the output end of the waste heat heat exchanger includes a first output end and a second output end, and the first output end and the second output end are combined and connected to the input end of the anode reactant pipeline through a second buffer tank; wherein a first flow valve is provided at the first output end, and a second flow valve is provided at the second output end.

[0013] Preferably, the output end of the fuel cell stack is provided with a tail exhaust waste heat utilization device and a tail exhaust valve in sequence; the tail exhaust waste heat utilization device is correspondingly connected between the second buffer tank and the input end of the anode reactant pipeline at the output end of the fuel cell stack, and is used to perform heat exchange with the anode reactant pipeline using the tail exhaust heat.

[0014] Preferably, the anode reactant pipeline is provided with a first pressure reducing valve, a second temperature regulator, a second pressure reducing valve, a first switch valve, a first humidifier and a second flow meter in sequence along the direction from the input end to the output end.

[0015] Preferably, an air compressor, a filter, a third temperature regulator, a second humidifier and a third flow meter are sequentially provided on the cathode reactant pipeline in the direction from the input end to the output end.

[0016] In a second aspect, the present invention further provides a method for thermal management of energy efficiency of a low-energy hydrogen fuel cell stack, based on the above-mentioned thermal management system of energy efficiency of a low-energy hydrogen fuel cell stack, comprising the following process: The liquid hydrogen storage tank converts the liquid hydrogen into low-temperature hydrogen after heating it through a hydrogen generator through a branch line. The low-temperature hydrogen enters the anode cooling pipeline and cathode cooling pipeline of several fuel cells for cooling; At the same time, the liquid hydrogen storage tank transports the liquid hydrogen to the waste heat heat exchanger through another branch. At this time, the hydrogen cooled in the anode cooling pipeline and the cathode cooling pipeline of the plurality of fuel cells enters the waste heat heat exchanger after temperature adjustment, and exchanges heat with the liquid hydrogen in the waste heat heat exchanger. The liquid hydrogen heats up and is converted into gaseous hydrogen, and is combined with the cooled hydrogen after being discharged from the waste heat heat exchanger and flows into the anode reactant pipeline. The anode reactant pipeline adjusts the temperature of the hydrogen and then inputs it into the anode reactant channels of the plurality of fuel cells as the anode reactant of the stack. At the same time, air is input into the input end of the cathode reactant pipeline and then filtered into the cathode reactant channels of the plurality of fuel cells. The plurality of fuel cells discharge water through the output end after the electrochemical reaction, wherein the water is discharged after heat exchange with the anode reactant hydrogen after the tail exhaust waste heat utilization device.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a low-energy consumption thermal management system for hydrogen fuel cell stacks. By using liquid hydrogen as a reactant and also as a coolant, the low-temperature hydrogen generated by heating the liquid hydrogen is used to implement thermal management of the hydrogen fuel cell stack, and the generated hydrogen is directly sent to the anode of the stack as a reactant, which simplifies the system configuration of the three circuits of the traditional fuel cell stack, and improves the energy utilization efficiency of the hydrogen fuel cell by utilizing the waste heat of the stack, effectively reducing the energy consumption of the overall system. The present invention adopts the low-temperature hydrogen obtained by pre-heating liquid hydrogen to perform the thermal management task of the fuel cell stack, which can effectively capture the waste heat released during the operation of the stack, and then use this part of the waste heat to promote the generation of hydrogen of the anode reactant, and use the thermal energy of the newly generated hydrogen to promote the gasification process of the liquid hydrogen in the anode gas path, thereby realizing the secondary efficient utilization of the waste heat, and thereby improving the overall energy conversion efficiency of the fuel cell stack.

[0018] Furthermore, the output end of the liquid hydrogen storage tank is provided with a hydrogen supply valve and a hydrogen pump in sequence along the hydrogen output direction, and the hydrogen supply valve accurately controls the output flow of hydrogen. By adjusting the opening of the hydrogen supply valve, the supply of hydrogen can be flexibly adjusted, and the hydrogen pump provides sufficient pressure for hydrogen to ensure that it can be smoothly transported to downstream equipment; by setting up a hydrogen pump, the pressure of hydrogen can be ensured to be stable during the transportation process, avoiding transportation problems caused by insufficient pressure.

[0019] Furthermore, a first buffer tank and a first flow meter are provided in sequence between the hydrogen generator and the input ends of the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells along the direction of hydrogen output. The first buffer tank can absorb or release hydrogen, thereby maintaining the relative stability of the system pressure and ensuring that the fuel cell can work continuously and stably. The first flow meter can monitor the flow rate of hydrogen during the transportation process in real time. By monitoring the flow data, the problem of insufficient or excessive hydrogen supply can be discovered and resolved in a timely manner, thereby ensuring the normal operation of the fuel cell.

[0020] Furthermore, the anode cooling pipeline and cathode cooling pipeline of several fuel cells have the same structure, which includes a mesh cooling pipeline structure and a spiral cooling pipeline structure. The mesh design can significantly increase the heat dissipation area of ​​the cooling pipeline, so that the heat can be transferred from the fuel cell to the cooling pipeline faster and quickly diffused into the air through the mesh structure. This helps to reduce the operating temperature of the fuel cell and improve its operating efficiency and stability. The mesh structure allows air to pass through the cooling pipeline more easily, thereby taking away more heat. The backflow and eddy current effect of the spiral wall can effectively increase the wall heat load and increase the heat exchange efficiency. The spiral cooling pipeline can better absorb and dissipate the heat generated by the fuel cell, ensuring that the fuel cell operates at the optimal operating temperature.

[0021] Furthermore, a first temperature regulator is provided between the output ends of the anode cooling pipeline and the cathode cooling pipeline of the plurality of fuel cells and the second input end of the waste heat heat exchanger, and the first temperature regulator can monitor and adjust the temperature of the cooling medium in real time to ensure that it remains within a suitable range before entering the waste heat heat exchanger. This helps to avoid the adverse effects of excessively high or low cooling medium temperature on the performance of the fuel cell, while ensuring that the waste heat heat exchanger can efficiently perform heat exchange.

[0022] Furthermore, the output end of the waste heat heat exchanger includes a first output end and a second output end, and the first output end and the second output end are combined and connected to the input end of the anode reactant pipeline through a second buffer tank; wherein a first flow valve is provided at the first output end, and a second flow valve is provided at the second output end, and the first flow valve and the second flow valve are arranged so that the flow of the two output ends of the waste heat heat exchanger can be controlled respectively. This helps to accurately adjust the flow of the cooling medium according to the specific needs of the anode reactant pipeline, thereby optimizing the heat exchange process and improving energy utilization efficiency.

[0023] Furthermore, the output end of the fuel cell stack is provided with a tail exhaust waste heat utilization device and a tail exhaust valve in sequence; the tail exhaust waste heat utilization device is connected between the second buffer tank and the input end of the anode reactant pipeline at the output end of the fuel cell stack, and is used for heat exchange of the anode reactant pipeline with the tail exhaust heat. The tail exhaust waste heat utilization device can capture the waste heat in the exhaust gas discharged by the fuel cell stack, and use the waste heat to preheat or heat the anode reactant pipeline. The anode reactant can reach a more suitable temperature before entering the fuel cell stack, which helps to improve the performance and efficiency of the fuel cell. By recycling the waste heat in the exhaust gas, energy waste is also reduced, and the energy utilization efficiency of the entire system is improved.

[0024] Further, the anode reactant pipeline is provided with a first pressure reducing valve, a second temperature regulator, a second pressure reducing valve, a first switch valve, a first humidifier and a second flow meter in sequence along the direction from the input end to the output end. The setting of the first pressure reducing valve can perform preliminary pressure regulation on the reactant entering the anode reactant pipeline to ensure that the pressure of the reactant in the pipeline is stable and appropriate. The second pressure reducing valve can perform more precise pressure regulation on the reactant to meet the specific requirements of the fuel cell stack for the reactant pressure. The setting of the second temperature regulator can accurately adjust the temperature of the reactant to ensure that the reactant reaches the most suitable temperature range before entering the fuel cell stack. The setting of the first switch valve makes it possible to conveniently control the flow of the reactant and realize the functions of starting, stopping and switching the system. The setting of the second flow meter can monitor the flow of the reactant in real time to ensure that the supply of the reactant is stable and meets the needs of the fuel cell stack. The setting of the first humidifier can humidify the reactant to ensure that the reactant contains an appropriate amount of water before entering the fuel cell stack.

[0025] Furthermore, an air compressor, a filter, a third temperature regulator, a second humidifier and a third flow meter are sequentially arranged on the cathode reactant pipeline in the direction from the input end to the output end. The setting of the air compressor ensures that the cathode reactant has sufficient flow and pressure to meet the needs of the fuel cell stack for electrochemical reaction. The setting of the filter effectively purifies the air entering the cathode reactant pipeline, removing impurities such as particles, dust and harmful gases in the air. The setting of the third temperature regulator can accurately adjust the temperature of the air entering the fuel cell stack. The setting of the second humidifier humidifies the air so that it contains an appropriate amount of moisture. The setting of the third flow meter can monitor the air flow entering the fuel cell stack in real time.

[0026] The present invention also provides a low-energy consumption thermal management method for the energy efficiency of hydrogen fuel cell stacks, which utilizes the low temperature characteristics of liquid hydrogen and divides it into two paths for thermal management. One path is directly used for the anode and cathode cooling pipelines of the fuel cell, which effectively reduces the operating temperature of the fuel cell and improves its working efficiency and stability. The other path exchanges heat with the cooled hydrogen through a waste heat heat exchanger, realizes the heating of liquid hydrogen and converts it into gaseous hydrogen. This process not only recovers the waste heat of cooling hydrogen, but also improves the utilization rate of liquid hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 A schematic diagram of the structure of a thermal management system for energy efficiency of a hydrogen fuel cell stack according to an embodiment of the present invention; Figure 2 Schematic diagram of the principle of a fuel cell stack in an embodiment of the present invention, wherein FIG (a) is a schematic diagram of the overall structure of the fuel cell stack; FIG (b) is a schematic diagram of the structure of a single fuel cell; FIG (c) is a schematic diagram of the cross-section of FIG (b); and FIG (d) is a schematic diagram of the pipeline distribution of the fuel cell in FIG (c); Figure 3 This is a schematic diagram of the mesh cooling pipeline structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the spiral cooling pipeline structure in an embodiment of the present invention; Figure 5 It is a schematic diagram of the internal principle of the waste heat heat exchanger in the embodiment of the present invention; In the figure: 1. liquid hydrogen storage tank; 2. hydrogen supply valve; 3. hydrogen pump; 4. hydrogen generator; 5. first buffer tank; 6. first flow meter; 7. first temperature regulator; 8. waste heat heat exchanger; 9. first flow valve; 10. second flow valve; 11. second buffer tank; 12. first pressure reducing valve; 13. second temperature regulator; 14. second pressure reducing valve; 15. first switch valve; 16. first humidifier; 17. second flow meter; 18. fuel cell stack; 19. third flow meter; 20. second humidifier; 21. third temperature regulator; 22. filter; 23. air compressor; 24. tail exhaust waste heat utilization device; 25. tail exhaust valve. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0028] The purpose of the present invention is to provide a low-energy consumption hydrogen fuel cell energy efficiency thermal management system and method to solve the technical problem of how to reduce energy consumption in the thermal management process while improving energy utilization efficiency in the prior art.

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings: Example 1 See also Figure 1 In one embodiment of the present invention, a low-energy consumption thermal management system for a hydrogen fuel cell stack is provided, comprising a liquid hydrogen storage tank 1, a hydrogen generator 4, a waste heat heat exchanger 8, an anode reactant pipeline, a fuel cell stack 18 and a cathode reactant pipeline; the fuel cell stack 18 comprises a plurality of fuel cells stacked in sequence; each of the plurality of fuel cells is provided with an anode cooling pipeline, an anode reactant channel, a cathode reactant channel, a cathode cooling pipeline and an output port from top to bottom; a branch road is provided at the output end of the liquid hydrogen storage tank 1, wherein one branch road is respectively connected to the anode reactant channel after passing through the hydrogen generator 4 To the input end of the anode cooling pipeline and the cathode cooling pipeline of several fuel cells; the other branch is connected to the first input end of the waste heat waste heat exchanger 8; the output ends of the anode cooling pipeline and the cathode cooling pipeline of the several fuel cells are connected to the second input end of the waste heat waste heat exchanger 8; the output end of the waste heat waste heat exchanger 8 is connected to the input end of the anode reactant pipeline; the output end of the anode reactant pipeline is connected to the anode reactant channel of several fuel cells; the input end of the cathode reactant pipeline is used to input air, and the output end is connected to the cathode reactant channel of several fuel cells.

[0030] Specifically, the output end of the liquid hydrogen storage tank 1 is provided with a hydrogen supply valve 2 and a hydrogen pump 3 in sequence along the hydrogen output direction.

[0031] In this embodiment, the hydrogen supply valve 2 accurately controls the output flow rate of hydrogen. By adjusting the opening of the hydrogen supply valve 2, the supply amount of hydrogen can be flexibly adjusted, and the hydrogen pump 3 provides sufficient pressure for the hydrogen to ensure that it can be smoothly transported to the downstream equipment. By setting the hydrogen pump 3, the pressure of hydrogen can be ensured to be stable during the transportation process, avoiding transportation problems caused by insufficient pressure.

[0032] Specifically, a first buffer tank 5 and a first flow meter 6 are sequentially provided between the hydrogen generator 4 and the input ends of the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells along the direction of hydrogen output.

[0033] In this embodiment, the first buffer tank 5 can absorb or release hydrogen, thereby maintaining the relative stability of the system pressure and ensuring that the fuel cell can work continuously and stably. The first flow meter 6 can monitor the flow rate of hydrogen during the transportation process in real time. By monitoring the flow data, the problem of insufficient or excessive hydrogen supply can be discovered and resolved in time, thereby ensuring the normal operation of the fuel cell.

[0034] Specifically, the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells have the same structure, which includes a mesh cooling pipeline structure and a spiral cooling pipeline structure.

[0035] Specifically, the mesh design can significantly increase the heat dissipation area of ​​the cooling pipeline, allowing heat to be transferred from the fuel cell to the cooling pipeline more quickly and diffused into the air through the mesh structure. This helps to reduce the operating temperature of the fuel cell and improve its operating efficiency and stability. The mesh structure allows air to pass through the cooling pipeline more easily, thereby taking away more heat. The backflow and eddy current effect of the spiral wall can effectively increase the wall heat load and increase the heat exchange efficiency. This allows the spiral cooling pipeline to better absorb and dissipate the heat generated by the fuel cell, ensuring that the fuel cell operates at the optimal operating temperature.

[0036] Among them, the mesh cooling pipeline structure in this embodiment is as follows Figure 3 As shown in the figure, the basic width of the channel section is 1mm, the height is 1mm, the length from the inlet to the outlet is 25mm, and the overall flow channel presents a gradient spider web shape. In the gradient grid, the basic grid is a square grid block with a length of 3mm. The square grid is increased twice along the parallel and vertical directions with a tolerance of 1mm, and the second gradient square block has a side length of 4mm, and the third gradient square block is 5mm, and then it decreases twice along the parallel and vertical directions with a tolerance of 1mm. In addition, the inlet and outlet are extended by 1mm.

[0037] Among them, the spiral cooling pipeline structure in this embodiment is as follows Figure 4 As shown, the channel cross-section width is 0.5 mm, the height is 1 mm, the length from the inlet to the outlet is 25 mm, and the overall flow channel presents a spiral distribution. In the spiral flow channel, each spiral is arranged at equal intervals, the arrangement spacing is 2 mm, and each spiral decreases with a tolerance of 4 mm. The length of the outermost spiral flow channel is 21 mm, and the minimum flow channel length of the inner layer is 3 mm. In addition, the inlet and the outlet are extended by 2 mm.

[0038] Specifically, a first temperature regulator 7 is provided between the output ends of the anode cooling pipelines and the cathode cooling pipelines of the plurality of fuel cells and the second input end of the waste heat heat exchanger 8 .

[0039] In this embodiment, the first temperature regulator 7 can monitor and adjust the temperature of the cooling medium in real time to ensure that it remains within a suitable range before entering the waste heat heat exchanger, which helps to avoid the adverse effects of excessively high or low cooling medium temperature on the performance of the fuel cell, while ensuring that the waste heat heat exchanger can efficiently perform heat exchange.

[0040] Specifically, according to Figure 5 As shown, the output end of the waste heat heat exchanger 8 includes a first output end and a second output end, and the first output end and the second output end are combined and connected to the input end of the anode reactant pipeline through a second buffer tank 11; wherein a first flow valve 9 is provided at the first output end, and a second flow valve 10 is provided at the second output end.

[0041] In this embodiment, the first flow valve 9 and the second flow valve 10 are arranged so that the flow rates at the two output ends of the waste heat heat exchanger can be controlled respectively, which helps to accurately adjust the flow rate of the cooling medium according to the specific requirements of the anode reactant pipeline, thereby optimizing the heat exchange process and improving energy utilization efficiency.

[0042] Specifically, the output end of the fuel cell stack is provided with a tail exhaust waste heat utilization device 24 and a tail exhaust valve 25 in sequence; the tail exhaust waste heat utilization device 24 is correspondingly connected between the second buffer tank 11 and the input end of the anode reactant pipeline at the output end of the fuel cell stack, and is used for heat exchange of the anode reactant pipeline with the tail exhaust heat.

[0043] In this embodiment, the tail exhaust waste heat utilization device 24 can capture the waste heat in the exhaust gas discharged by the fuel cell stack, and use this waste heat to preheat or heat the anode reactant pipeline. The anode reactant can reach a more suitable temperature before entering the fuel cell stack, which helps to improve the performance and efficiency of the fuel cell. By recycling the waste heat in the exhaust gas, energy waste is also reduced, and the energy utilization efficiency of the entire system is improved.

[0044] Specifically, the anode reactant pipeline is provided with a first pressure reducing valve 12, a second temperature regulator 13, a second pressure reducing valve 14, a first switch valve 15, a first humidifier 16 and a second flow meter 17 in sequence from the input end to the output end.

[0045] The setting of the first pressure reducing valve 12 in this embodiment can perform preliminary pressure regulation on the reactants entering the anode reactant pipeline to ensure that the pressure of the reactants in the pipeline is stable and appropriate. The second pressure reducing valve 14 can perform more accurate pressure regulation on the reactants to meet the specific requirements of the fuel cell stack for the reactant pressure. The setting of the second temperature regulator 13 can accurately adjust the temperature of the reactants to ensure that the reactants reach the most suitable temperature range before entering the fuel cell stack. The setting of the first switch valve 15 makes it possible to easily control the flow of the reactants and realize the functions of starting, stopping and switching the system. The setting of the second flowmeter 17 can monitor the flow of the reactants in real time to ensure that the supply of the reactants is stable and meets the needs of the fuel cell stack. The setting of the first humidifier 16 can humidify the reactants to ensure that the reactants contain an appropriate amount of water before entering the fuel cell stack.

[0046] Specifically, an air compressor 23, a filter 22, a third temperature regulator 21, a second humidifier 20 and a third flow meter 19 are sequentially provided on the cathode reactant pipeline in the direction from the input end to the output end.

[0047] The setting of the air compressor 23 in this embodiment ensures that the cathode reactant has sufficient flow and pressure to meet the needs of the fuel cell stack for electrochemical reaction. The setting of the filter 22 effectively purifies the air entering the cathode reactant pipeline, removing impurities such as particles, dust and harmful gases in the air. The setting of the third temperature regulator 21 can accurately adjust the temperature of the air entering the fuel cell stack. The setting of the second humidifier 20 humidifies the air so that it contains an appropriate amount of moisture. The setting of the third flowmeter 19 can monitor the air flow entering the fuel cell stack in real time.

[0048] according to Figure 2 As shown, the working principle of the mesh cooling pipeline structure of the fuel cell used in this embodiment is as follows: During the reaction of the fuel cell stack, the heat of the reactants introduced into the positive and negative electrodes is transferred to the fuel cell stack plate layer through convection heat exchange, and the plate layer material transfers the heat near the reactant channel to the plate near the cooling channel through heat conduction. The low-temperature hydrogen gas introduced into the fuel cell stack passes through the cooling channel. The low-temperature, high-heat-capacity liquid hydrogen flows along the cooling flow channel and forced convection with the heat on the plate wall takes away the heat. The complex mesh surface extends the heat exchange path with the plate, increasing the time and stroke of heat exchange, and realizing efficient thermal management of the fuel cell.

[0049] In this embodiment, the hydrogen generator 4 and the temperature regulator use PTC thermistors for temperature regulation, and the flow meter plays a role in flow monitoring.

[0050] In summary, this embodiment provides a low-energy consumption thermal management system for the energy efficiency of hydrogen fuel cell stacks. By using liquid hydrogen as a reactant and also as a coolant, and by heating the low-temperature hydrogen generated by liquid hydrogen, the hydrogen fuel cell stack is thermally managed, and the generated hydrogen is directly sent to the anode of the stack as a reactant, which simplifies the system configuration of the three circuits of the traditional fuel cell stack, and improves the energy utilization efficiency of the hydrogen fuel cell by utilizing the waste heat of the stack, effectively reducing the energy consumption of the overall system. The present invention adopts the low-temperature hydrogen obtained by pre-heating liquid hydrogen to perform the thermal management task of the fuel cell stack, which can effectively capture the waste heat released during the operation of the stack, and then use this part of the waste heat to promote the generation of hydrogen from the anode reactants, and use the thermal energy of these newly generated hydrogen to promote the gasification process of liquid hydrogen in the anode gas path, thereby realizing the secondary efficient utilization of waste heat, and thereby improving the overall energy conversion efficiency of the fuel cell stack.

[0051] Example 2 This embodiment provides a method for thermal management of energy efficiency of a low-energy hydrogen fuel cell stack, based on the above-mentioned thermal management system for energy efficiency of a low-energy hydrogen fuel cell stack, including the following process: The liquid hydrogen storage tank 1 converts the liquid hydrogen into low-temperature hydrogen after heating it through a hydrogen generator 4 via a branch. The low-temperature hydrogen enters the anode cooling pipeline and cathode cooling pipeline of several fuel cells through the first buffer tank 5 for cooling; wherein, the first buffer tank 5 plays a rectifying role, ensuring that the low-temperature hydrogen smoothly enters the fuel cell stack, and utilizes the heat generated by the operation of the fuel cell stack for heat exchange.

[0052] At the same time, the liquid hydrogen storage tank 1 transports the liquid hydrogen to the waste heat heat exchanger 8 through another branch. At this time, the hydrogen cooled in the anode cooling pipeline and the cathode cooling pipeline of the plurality of fuel cells enters the waste heat heat exchanger 8 after temperature adjustment, and performs heat exchange with the liquid hydrogen in the waste heat heat exchanger 8. The liquid hydrogen is heated and converted into gaseous hydrogen, and is combined with the cooled hydrogen after being discharged from the waste heat heat exchanger 8 and flows into the anode reactant pipeline through the second buffer tank 11. The hydrogen rectified by the second buffer tank 11 is pressure-reduced in the anode reactant pipeline by the first pressure reducing valve 12, and is again passed through the second temperature regulator 13 to ensure that its temperature is suitable as a reactant for the anode of the fuel cell stack. After being reduced in pressure to 100-250 kPa, the hydrogen enters the first humidifier 15 for humidity adjustment, so that its humidity is maintained in the range of 30% to 70%, and finally passes into the anode of the fuel cell stack for electrochemical reaction.

[0053] The anode reactant pipeline adjusts the temperature of hydrogen and then inputs it into the anode reactant channels of several fuel cells. At the same time, the input end of the cathode reactant pipeline inputs air and then enters the cathode reactant channels of several fuel cells after being filtered. The low-temperature air is pressurized to 120-200 kPa by the air compressor 23 and drawn into the cathode reactant pipeline, filtered by the filter 22, heated to 40-55°C by the third temperature regulator 21, and the humidity is 30%-70%, and then humidified by the second humidifier 20 before entering the fuel cell cathode for reaction.

[0054] Among them, the low-temperature air is first pressurized by the air compressor 23, and the pressure range is set between 120 and 200 kPa, and then introduced into the cathode reactant pipeline. Then, the air is purified through a filter to ensure its purity. Subsequently, the third temperature regulator 21 heats it to a suitable range, i.e., 40 to 55 degrees Celsius. At the same time, the humidity of the air is also adjusted to an ideal level, maintained between 30% and 70%. After completing the temperature and humidity adjustment, the air will be further humidified by the second humidifier 20 to ensure that it contains enough water. Finally, this conditioned air enters the cathode of the fuel cell and participates in the electrochemical reaction.

[0055] The plurality of fuel cells discharge water through the output end after the electrochemical reaction, wherein the water is discharged after heat exchange with the anode reactant hydrogen using the waste heat of the fuel cell stack after the tail exhaust waste heat utilization device 24 .

[0056] This embodiment focuses on the rational use of cooling medium and the streamlined design of the fuel cell system structure. Compared with the traditional three-circuit fuel cell system, this embodiment innovatively integrates the cooling circuit and the anode reaction gas passage, and allows the cooling medium to be converted into hydrogen after absorbing the reaction waste heat and directly used as a subsequent reactant. This design not only realizes the recycling of cooling medium, but also simplifies the overall architecture of the fuel cell system, and improves the system's integration and efficiency.

[0057] In summary, the present invention provides a low-energy thermal management method for the energy efficiency of a hydrogen fuel cell stack, which utilizes the low-temperature characteristics of liquid hydrogen and is divided into two paths for thermal management. One path is directly used for the anode and cathode cooling pipelines of the fuel cell, which effectively reduces the operating temperature of the fuel cell and improves its working efficiency and stability. The other path exchanges heat with the cooled hydrogen through a waste heat heat exchanger, thereby heating the liquid hydrogen and converting it into gaseous hydrogen. This process not only recovers the waste heat of the cooled hydrogen, but also improves the utilization rate of the liquid hydrogen. In this embodiment, in the cooling circuit, low-temperature hydrogen is used as a cooling medium to effectively absorb the heat generated during the operation of the fuel cell stack and then converted into higher-temperature hydrogen. This part of hydrogen is not directly discharged from the fuel cell stack system, but is guided into the hydrogen vaporization device, where the waste heat of the fuel cell stack is used to exchange heat with liquid hydrogen, thereby fully exploring and utilizing its thermal energy potential, thereby enhancing the working efficiency of the fuel cell stack.

[0058] This embodiment achieves simplified optimization of the cooling circuit outlet by directly connecting the cooling circuit outlet to the anode reactant circuit inlet. In this process, part of the hydrogen in the cooling circuit is not directly discharged, but is redirected to the anode reactant circuit according to this strategy, and serves as the key medium of the anode reaction, thereby achieving the recycling of the working medium.

[0059] 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A low-energy consumption thermal management system for hydrogen fuel cell energy efficiency, characterized in that: It comprises a liquid hydrogen storage tank (1), a hydrogen generator (4), a waste heat and residual heat exchanger (8), an anode reactant pipeline, a fuel cell stack (18), and a cathode reactant pipeline; The fuel cell stack (18) comprises a plurality of fuel cells stacked in sequence; each of the plurality of fuel cells is provided with an anode cooling pipeline, an anode reactant channel, a cathode reactant channel, a cathode cooling pipeline and an output port from top to bottom; The output end of the liquid hydrogen storage tank (1) is provided with branch lines, one of which is connected to the input ends of the anode cooling pipelines and cathode cooling pipelines of a plurality of fuel cells after passing through the hydrogen generator (4); the other branch is connected to the first input end of the waste heat heat exchanger (8); the output ends of the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells are connected to the second input end of the waste heat heat exchanger (8); The output end of the waste heat heat exchanger (8) is connected to the input end of the anode reactant pipeline; the output end of the anode reactant pipeline is connected to the anode reactant channels of a plurality of fuel cells; the input end of the cathode reactant pipeline is used to input air, and the output end is connected to the cathode reactant channels of a plurality of fuel cells.

2. The low energy consumption thermal management system for hydrogen fuel cell stack energy efficiency according to claim 1 is characterized in that: The output end of the liquid hydrogen storage tank (1) is provided with a hydrogen supply valve (2) and a hydrogen pump (3) in sequence along the hydrogen output direction.

3. The low energy consumption thermal management system for hydrogen fuel cell energy efficiency according to claim 1 is characterized in that: A first buffer tank (5) and a first flow meter (6) are provided in sequence between the hydrogen generator (4) and the input ends of the anode cooling pipelines and cathode cooling pipelines of a plurality of fuel cells along the direction of hydrogen output.

4. The low energy consumption thermal management system for hydrogen fuel cell energy efficiency according to claim 1 is characterized in that: The anode cooling pipelines and cathode cooling pipelines of several fuel cells have the same structure, which includes a mesh cooling pipeline structure and a spiral cooling pipeline structure.

5. The low energy consumption hydrogen fuel cell energy efficiency thermal management system according to claim 1 is characterized in that: A first temperature regulator (7) is provided between the output ends of the anode cooling pipelines and cathode cooling pipelines of the plurality of fuel cells and the second input end of the waste heat heat exchanger (8).

6. The low energy consumption hydrogen fuel cell energy efficiency thermal management system according to claim 1 is characterized in that: The output end of the waste heat heat exchanger (8) comprises a first output end and a second output end, wherein the first output end and the second output end are combined and connected to the input end of the anode reactant pipeline via a second buffer tank (11); wherein a first flow valve (9) is provided at the first output end, and a second flow valve (10) is provided at the second output end.

7. The low energy consumption hydrogen fuel cell energy efficiency thermal management system according to claim 1 is characterized in that: The output end of the fuel cell stack is provided with a tail exhaust waste heat utilization device (24) and a tail exhaust valve (25) in sequence; the tail exhaust waste heat utilization device (24) is connected between the second buffer tank (11) and the input end of the anode reactant pipeline at the output end of the fuel cell stack, and is used for heat exchange of the anode reactant pipeline with the tail exhaust heat.

8. The low energy consumption hydrogen fuel cell stack energy efficiency thermal management system according to claim 1, characterized in that: The anode reactant pipeline is provided with a first pressure reducing valve (12), a second temperature regulator (13), a second pressure reducing valve (14), a first switch valve (15), a first humidifier (16) and a second flow meter (17) in sequence along the direction from the input end to the output end.

9. The low energy consumption hydrogen fuel cell stack energy efficiency thermal management system according to claim 1, characterized in that: An air compressor (23), a filter (22), a third temperature regulator (21), a second humidifier (20) and a third flow meter (19) are sequentially arranged on the cathode reactant pipeline in a direction from the input end to the output end.

10. A method for thermal management of energy efficiency of a low-energy hydrogen fuel cell stack, characterized in that: A thermal management system for improving the energy efficiency of a low-energy hydrogen fuel cell stack according to any one of claims 1 to 9, comprising the following process: The liquid hydrogen storage tank (1) heats the liquid hydrogen through a branch line through a hydrogen generator (4) and converts it into low-temperature hydrogen, and the low-temperature hydrogen enters the anode cooling pipeline and cathode cooling pipeline of a plurality of fuel cells for cooling; At the same time, the liquid hydrogen storage tank (1) transports the liquid hydrogen to the waste heat heat exchanger (8) through another branch. At this time, the hydrogen gas cooled in the anode cooling pipeline and the cathode cooling pipeline of the plurality of fuel cells enters the waste heat heat exchanger (8) after temperature adjustment, and exchanges heat with the liquid hydrogen in the waste heat heat exchanger (8). The liquid hydrogen is heated and converted into gaseous hydrogen, and is combined with the cooled hydrogen gas after being discharged from the waste heat heat exchanger (8) and flows into the anode reactant pipeline. The anode reactant pipeline adjusts the temperature of the hydrogen gas and then inputs it into the anode reactant channels of the plurality of fuel cells as the anode reactant of the stack. At the same time, air is input into the input end of the cathode reactant pipeline and then filtered to enter the cathode reactant channels of the plurality of fuel cells. The plurality of fuel cells discharge water through the output end after the electrochemical reaction, wherein the water is discharged after heat exchange with the anode reactant hydrogen after the tail exhaust waste heat utilization device (24).

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