Vehicle-mounted liquid hydrogen gasification hydrogen supply system and control method thereof

Abstract

This invention discloses an on-board liquid hydrogen vaporization hydrogen supply system and its control method. The system includes: a coolant heat exchange system connected to the coolant inlet and outlet of the fuel cell stack; a hydrogen supply heat exchange system connected to the hydrogen inlet of the fuel cell stack, and the hydrogen supply heat exchange system is connected to the coolant heat exchange system to allow heat exchange between the coolant in the coolant heat exchange system and the hydrogen in the hydrogen supply heat exchange system; and a heater installed in a first connecting pipe for connecting the hydrogen supply heat exchange system and the coolant heat exchange system, used to heat the coolant flowing from the coolant heat exchange system to the hydrogen supply heat exchange system, thereby achieving heat exchange between the coolant and hydrogen to raise the hydrogen temperature to reach the set temperature for entering the fuel cell stack. This disclosure utilizes the characteristic that "liquid hydrogen needs to absorb heat to vaporize into gaseous hydrogen" to reduce the energy consumption of the cooling cycle system in the fuel cell system, improve the overall vehicle energy utilization rate, and simultaneously solve the problem of thermal shock to the fuel cell stack caused by hydrogen overcooling.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell technology, and more specifically, to an on-board liquid hydrogen vaporization hydrogen supply system and its control method. Background Technology

[0002] Fuel cell power systems are gradually replacing traditional internal combustion engine power systems and are widely used in transportation equipment such as automobiles, ships, and aviation. Hydrogen is the reaction fuel in fuel cell systems, and the amount of hydrogen carried determines the total amount of electricity the system can generate.

[0003] Currently, hydrogen storage / supply systems for hydrogen fuel cell vehicles mainly rely on high-pressure gaseous hydrogen storage, with 35MPa and 70MPa being the most common. Although this technology is relatively mature and widely used, its safety and hydrogen storage density (the density of 70MPa at 15℃ is 40.2115kg / m³) are not optimistic compared to other hydrogen storage technologies.

[0004] Compared with high-pressure gaseous hydrogen storage, liquid hydrogen has advantages such as high volumetric hydrogen storage density (density as high as 70.9857 kg / m³ at atmospheric pressure) and low operating pressure (between 1 MPa and 2 MPa). Therefore, liquid hydrogen has good application prospects in the hydrogen energy industry.

[0005] Furthermore, liquid hydrogen has a temperature of approximately -252.78°C at atmospheric pressure. Since fuel cell power systems require gaseous hydrogen in practice, it's necessary to convert liquid hydrogen to gaseous hydrogen before use. Traditional conversion methods involve placing a heater at the liquid hydrogen outlet to achieve this conversion. However, this method presents certain safety risks and cannot guarantee that the liquid hydrogen is completely converted before flowing to the fuel cell stack. It also cannot ensure that the temperature of the converted gaseous hydrogen meets the operating requirements of the fuel cell power system. Both excessively low and high hydrogen temperatures can cause thermal shock to the fuel cell stack. Additionally, this method, by adding a heater, leads to energy waste and increased costs. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide an on-board liquid hydrogen vaporization hydrogen supply system and its control method to solve the above-mentioned technical problems.

[0007] To address the aforementioned problems, the first objective of this invention is to provide an on-board liquid hydrogen vaporization hydrogen supply system, comprising: a coolant heat exchange system connected to the coolant inlet and outlet of the fuel cell stack; a hydrogen supply heat exchange system connected to the hydrogen inlet of the fuel cell stack, and the hydrogen supply heat exchange system being connected to the coolant heat exchange system to allow heat exchange between the coolant in the coolant heat exchange system and the hydrogen in the hydrogen supply heat exchange system; and a heater disposed in a first connecting pipe for connecting the hydrogen supply heat exchange system and the coolant heat exchange system, for heating the coolant flowing from the coolant heat exchange system to the hydrogen supply heat exchange system, thereby achieving heat exchange between the coolant and hydrogen to raise the temperature of the hydrogen to reach the set temperature for entering the fuel cell stack; the coolant after heat exchange with hydrogen flows back to the coolant heat exchange system via a second connecting pipe.

[0008] Optionally, a portion of the coolant from the fuel cell stack flows through the first connecting pipe to the heater, and after heating the hydrogen, it flows through the second connecting pipe to exchange heat with the remaining portion of the coolant from the fuel cell stack to the coolant heat exchange system, and then merges and flows to the coolant inlet of the fuel cell stack.

[0009] Optionally, the hydrogen supply heat exchange system includes a liquid hydrogen cylinder for storing liquid hydrogen, a liquid hydrogen vaporizer, a gas temperature sensor, a solenoid valve, and a buffer tank. The hydrogen inlet of the liquid hydrogen vaporizer is connected to the liquid hydrogen cylinder, and the hydrogen outlet of the liquid hydrogen vaporizer is sequentially connected to the gas temperature sensor, the solenoid valve, and the buffer tank. The end of the buffer tank away from the solenoid valve is connected to the hydrogen inlet of the fuel cell stack. The coolant flowing through the heater via the first connecting pipe is heated by the liquid hydrogen vaporizer and then returned to the coolant heat exchange system via the second connecting pipe.

[0010] Optionally, the coolant heat exchange system includes a small-circulation cooling system and a large-circulation cooling system. The small-circulation cooling system is adapted to rapidly raise the temperature of the fuel cell stack to the operating temperature range when the fuel cell system is started. The large-circulation cooling system is adapted to cool and circulate the high-temperature coolant flowing out of the fuel cell stack back to the fuel cell stack after the temperature of the fuel cell stack reaches the operating temperature range.

[0011] Optionally, the small-circuit cooling system includes a cooling water pump, a first electric heater, a thermostat, and a three-way valve. The inlet of the cooling water pump is connected to the coolant drain port of the fuel cell stack, so that a portion of the coolant exiting the cooling water pump flows to the first electric heater or the large-circuit cooling system. The other end of the first electric heater is connected to the F inlet of the thermostat. The E outlet of the thermostat is connected to the A inlet of the three-way valve, and the B outlet of the three-way valve is connected to the coolant inlet of the fuel cell stack. The remaining portion of the coolant exiting the cooling water pump flows to the heater through the first connecting pipe, and the C inlet of the three-way valve is connected to the second connecting pipe.

[0012] Optionally, the large-circulation cooling system includes a radiator and a particulate filter, and a portion of the coolant flowing into the large-circulation cooling system flows sequentially through the radiator, the particulate filter, and the D inlet of the thermostat.

[0013] Optionally, the large-circulation cooling system further includes an expansion tank and a deionizer, with a portion of the coolant flowing into the large-circulation cooling system passing sequentially through the deionizer, the expansion tank, and the cooling water pump; the expansion tank is connected to the exhaust port of the fuel cell stack.

[0014] Optionally, it also includes a hydrogen buffering system connected to the end of the buffer tank, the hydrogen buffering system including a pressure relief valve and a discharge protector connected in sequence.

[0015] Optionally, the second connecting pipe, the coolant inlet of the fuel cell stack, and the coolant outlet of the fuel cell stack are all equipped with temperature sensors to detect the temperature of the coolant.

[0016] Optionally, the system further includes a hydrogen regulation system connected between the buffer tank and the fuel cell stack. The hydrogen regulation system includes a filter, a hydrogen pressure sensor, a pressure regulating valve, a hydrogen inlet solenoid valve, and a proportional valve connected in sequence. The side of the filter away from the hydrogen pressure sensor is connected to the buffer tank, and the side of the proportional valve away from the hydrogen inlet solenoid valve is connected to the hydrogen inlet of the fuel cell stack.

[0017] A second objective of this invention is to provide an on-board liquid hydrogen vaporization hydrogen supply control method, applicable to the on-board liquid hydrogen vaporization hydrogen supply system as described above, wherein the on-board liquid hydrogen vaporization hydrogen supply control method includes:

[0018] During the thermal management of the coolant heat exchange system for the fuel cell stack and hydrogen supply heat exchange system, the following steps are performed:

[0019] Obtain the hydrogen inlet temperature of the fuel cell stack;

[0020] When the hydrogen inlet temperature is lower than the hydrogen set temperature of the fuel cell stack, the following steps are executed:

[0021] The heater installed in the first connecting pipe is activated to heat the coolant flowing through it until the hydrogen entering the stack after heat exchange with it reaches the hydrogen set temperature of the stack.

[0022] Optionally, the thermal management of the fuel cell stack and hydrogen supply heat exchange system in the coolant heat exchange system specifically includes the following steps:

[0023] S1: When the fuel cell system is started, the small-circulation cooling system of the coolant heat exchange system works, which causes the stack temperature to rise rapidly to the operating temperature range; during this period, part of the coolant flowing out of the stack flows to the hydrogen supply heat exchange system to exchange heat with hydrogen, and the remaining part flows to the large-circulation cooling system, and finally flows to the coolant inlet of the stack.

[0024] S2: When the temperature of the fuel cell stack reaches the operating temperature range, the large-circulation cooling system of the coolant heat exchange system operates to circulate and cool the high-temperature coolant flowing out of the fuel cell stack; during this period, part of the coolant flowing out of the fuel cell stack flows to the hydrogen supply heat exchange system to exchange heat with hydrogen, and the remaining part flows to the large-circulation cooling system, and finally converges to the coolant inlet of the fuel cell stack.

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

[0026] 1. The on-board liquid hydrogen vaporization and hydrogen supply system in this application includes a coolant heat exchange system and a hydrogen supply heat exchange system. When the fuel cell system is first started, the coolant heat exchange system is adapted to rapidly raise the stack temperature to a suitable operating temperature range. After the stack temperature in the fuel cell system reaches the suitable operating temperature range, the coolant heat exchange system cools and circulates the high-temperature coolant flowing out of the stack back to the stack. The hydrogen supply heat exchange system is adapted to absorb heat and vaporize liquid hydrogen into gaseous hydrogen with a temperature suitable for the fuel cell system under the heat exchange action of the fuel cell coolant. Under the thermal management constraints that the temperature difference between the coolant entering and exiting the stack should be maintained at about 10°C, and the optimal operating temperature of the stack is 60-80°C, and other conditions where the coolant heat exchange system cannot meet the energy consumption and entry temperature requirements for hydrogen vaporization, the heater heats the coolant flowing towards the hydrogen. Heating ensures that the coolant heat exchange system can only meet the thermal management needs of the fuel cell stack, but cannot guarantee that the hydrogen inlet temperature meets the energy consumption required for hydrogen vaporization at the set hydrogen temperature and the inlet temperature. This avoids thermal shock to the fuel cell stack caused by excessively low hydrogen temperature (such as anode flooding, heat exchange with other fuel cell components affecting their performance, etc.). For example, when the fuel cell system experiences a "short shutdown and restart", both the large and small circulation loops of the coolant heat exchange system are closed. The heater can solve the problem that the high-temperature coolant flowing out of the fuel cell stack can utilize the characteristic that "liquid hydrogen needs to absorb heat to vaporize into gaseous hydrogen". Therefore, in this operating condition, it is not necessary to open the large and small circulation loops, but only the circulation loop where the heater is located needs to be opened, reducing the energy consumption of the cooling circulation system in the fuel cell system and improving the energy utilization rate of the entire vehicle. In summary, this disclosure not only recovers and reuses the waste heat generated by the fuel cell stack (through heat exchange with hydrogen to achieve energy recovery), but also ensures the energy consumption required for hydrogen vaporization and its inlet temperature by heating the coolant, avoiding thermal shock to the fuel cell stack due to excessively low hydrogen temperature. Furthermore, since the heater does not come into direct contact with the hydrogen, the operational stability and safety of the entire system are improved. Excessively low hydrogen temperature is addressed by the heater, while excessively high hydrogen temperature can be addressed by the coolant heat exchange system (which can be achieved by reducing the flow rate or temperature of the coolant flowing to the hydrogen while meeting the fuel cell stack thermal management requirements). This ensures that the thermal management of the fuel cell stack and hydrogen are coordinated and mutually adaptable, guaranteeing the stability, reliability, safety, and effective service life of the entire fuel cell system.

[0027] 2. When the fuel cell system is started up in a low-temperature environment (below 0°C), the fuel cell coolant flowing into the stack is heated by the first electric heater. At this time, the fuel cell cooling circulation system is in a small circulation, so that the temperature of the stack reaches at least above 0°C. When the temperature of the stack reaches above 0°C, the temperature of the fuel cell coolant flowing out of the stack is lower than the set temperature, and it cannot provide enough heat to allow the liquid hydrogen to absorb heat and vaporize into gaseous hydrogen that meets the hydrogen set temperature of the downstream stack. By starting the heater, the fuel cell coolant flowing into the liquid hydrogen vaporizer from the cooling water pump is heated so that it can exchange heat with the liquid hydrogen flowing through the spiral coil of the liquid hydrogen vaporizer, so that the liquid hydrogen can be fully vaporized into gaseous hydrogen that meets the hydrogen set temperature of the downstream stack.

[0028] 3. Liquid hydrogen vaporizers can be counter-current (the cold and hot fluids flow in opposite directions in the heat exchanger). Compared with co-current flow, counter-current flow requires a smaller heat exchange area (the liquid hydrogen vaporizer is smaller) and has higher heat exchange efficiency.

[0029] 4. By monitoring the temperatures of the coolant entering and exiting the stack and the coolant exiting the hydrogen vaporizer, technical support is provided for coordinating stack thermal management and hydrogen thermal management, allocating the coolant ratio between the stack and hydrogen, and controlling the start-up and shutdown of the heaters. This ensures the rational distribution of coolant while simultaneously achieving optimal stack and hydrogen thermal management. Furthermore, the expansion tank and deionizer ensure the supply and quality of coolant, providing technical support for the thermal management performance of the stack and hydrogen, as well as the operation of the entire fuel cell system.

[0030] 5. The installation of a buffer tank, pressure relief valve, and emission protector can meet the hydrogen demand of the fuel cell system during initial startup, while also improving the safety performance of the entire system. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the vehicle-mounted liquid hydrogen vaporization hydrogen supply system in an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1- Coolant heat exchange system;

[0034] 11-Small-circulation cooling system;

[0035] 111-Cooling water pump; 112-First electric heater; 113-Thermostat; 114-Three-way valve;

[0036] 12-Large-circulation cooling system;

[0037] 121-Radiator; 122-Particulate filter; 123-Expansion tank; 124-Deionizer;

[0038] 2- Hydrogen supply heat exchange system;

[0039] 21-Liquid hydrogen cylinder; 22-Liquid hydrogen vaporizer; 23-Gas temperature sensor; 24-Solenoid valve; 25-Buffer tank; 27-Filter; 28-Hydrogen pressure sensor; 29-Pressure regulating valve;

[0040] 3-Heater; 4-Temperature sensor; 5-Liquid hydrogen system controller; 6-Fuel stack;

[0041] 7- Hydrogen buffer system;

[0042] 71-Pressure relief valve; 72-Emission protector;

[0043] 8- Hydrogen regulation system;

[0044] 81-Filter; 82-Hydrogen pressure sensor; 83-Pressure regulating valve; 84-Hydrogen inlet solenoid valve; 85-Proportional valve. Detailed Implementation

[0045] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be noted that the terms "first," "second," ... "fourth," etc., are used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0049] Please see Figure 1 As shown, this embodiment of the invention provides an on-board liquid hydrogen vaporization hydrogen supply system, which includes a coolant heat exchange system 1, a hydrogen supply heat exchange system 2, and a heater 3, wherein:

[0050] The coolant heat exchange system 1 is connected to the coolant inlet and outlet of the fuel cell stack 6 to regulate the temperature of the heat generated during the fuel cell system reaction process, so as to avoid the performance of the fuel cell system being affected by excessively high or low temperatures.

[0051] The hydrogen supply heat exchange system 2 is connected to the hydrogen inlet of the fuel cell stack 6, and is also connected to the coolant heat exchange system 1 to allow heat exchange between the coolant in the coolant heat exchange system 1 and the hydrogen in the hydrogen supply heat exchange system 2. Specifically, in an embodiment of the present invention, the hydrogen supply heat exchange system 2 and the coolant heat exchange system 1 are connected via a four-way valve (not shown in the figure). In some other embodiments, branch lines, hydraulic valves, etc., can be used for connection instead of the multi-way valves mentioned in this application (such as three-way valve 114, thermostat 113, four-way valve, etc.).

[0052] The heater 3 is connected to the first connecting pipe between the hydrogen supply heat exchange system 2 and the coolant heat exchange system 1 to heat the coolant flowing from the coolant heat exchange system 1 to the hydrogen supply heat exchange system 2, so as to realize the heat exchange between the coolant and the hydrogen, so that the hydrogen temperature rises to reach the set temperature of hydrogen entering the fuel cell stack 6; the coolant after heat exchange with the hydrogen flows back to the coolant heat exchange system 1 through the second connecting pipe.

[0053] It is understood that heater 3 can be any heat exchanger, such as an electric heater, electromagnetic heater, or infrared heater. As the preferred embodiment of this invention, an electric heater is selected and installed on the first connecting pipe to exchange heat with the coolant flowing within it. This method is convenient and simple to operate and install. In this embodiment, the heater heats the coolant used for heat exchange with hydrogen to raise its temperature, i.e., indirectly heating the hydrogen. This method differs from the existing unsafe and temperature-uncontrollable method of directly heating hydrogen with a heater. Safety, energy efficiency, environmental friendliness, and the stability of the hydrogen entry temperature are greatly improved, effectively avoiding thermal shock problems caused by excessively high or low hydrogen entry temperatures and other subsequent adverse phenomena.

[0054] In a fuel cell system, hydrogen and oxygen undergo an electrochemical reaction, generating electricity but also producing heat. To prevent excessively high or low temperatures from affecting the fuel cell system's performance, a cooling circulation system is used to regulate the temperature, ensuring it operates within its optimal range (+60℃ to +80℃), and maintaining the temperature difference between the coolant entering and exiting the stack at approximately 10℃. The vaporization of liquid hydrogen into gaseous hydrogen requires heat absorption, and the heat generated during the reaction process in the fuel cell system can serve as the energy source for this vaporization. Therefore, by utilizing this characteristic of heat absorption during the vaporization of liquid hydrogen into gaseous hydrogen, the energy consumption of the cooling circulation system in the fuel cell system can be reduced, improving the overall vehicle energy efficiency.

[0055] For example, when a fuel cell system is shut down for a long time (e.g., overnight), before restarting and entering normal operation, it needs to be purged (hydrogen is used to purge the anode circuit during startup to remove impurities that have permeated into the anode circuit during shutdown). At this time, the temperature of the fuel cell coolant flowing out of the stack 6 is lower than a certain temperature, and it cannot provide enough heat to allow the liquid hydrogen in the hydrogen heat exchange system 2 to absorb heat and vaporize into gaseous hydrogen that meets the hydrogen set temperature of the downstream fuel cell system.

[0056] Therefore, in this situation, heater 3 is activated to heat the coolant flowing from coolant heat exchange system 1 to hydrogen supply heat exchange system 2, so that the coolant exchanges heat with hydrogen to raise the temperature of the hydrogen to reach the set temperature for entering the fuel cell stack 6.

[0057] It should be noted that the fuel cell system in this embodiment can be used not only for PEM fuel cell systems, but also for any fuel cell system, such as proton exchange membrane (PEM) fuel cells, which convert hydrogen and oxygen into water to release energy. The core of the fuel cell is a proton exchange membrane (catalyst coating membrane, CCM) coated with platinum-based catalysts on both sides.

[0058] Please see Figure 1 As shown, in an embodiment of the present invention, a portion of the coolant exiting the fuel cell stack 6 flows through the first connecting pipe to the heater 3 to heat the hydrogen. Then, it flows through the second connecting pipe to the remaining portion of the coolant exiting the fuel cell stack 6, where it exchanges heat with the coolant heat exchange system 1 before converging and flowing back to the coolant inlet of the fuel cell stack 6. In this embodiment, a portion of the coolant used to heat the hydrogen exits the fuel cell stack 6, thereby enabling the reuse of waste heat from the fuel cell stack 6. This shares some of the heat load with the coolant heat exchange system 1, reducing the energy consumption of the fuel cell stack 6's thermal management while simultaneously meeting the requirements for hydrogenation and inlet temperature. This makes the present application more energy-efficient and scientifically sound.

[0059] Please see Figure 1 As shown in the specific embodiment of the present invention, the hydrogen heat exchange system 2 includes a liquid hydrogen cylinder 21 for storing liquid hydrogen, a liquid hydrogen vaporizer 22, a gas temperature sensor 23, a solenoid valve 24, and a buffer tank 25. The hydrogen inlet of the liquid hydrogen vaporizer 22 is connected to the liquid hydrogen cylinder 21, and the hydrogen outlet of the liquid hydrogen vaporizer 22 is sequentially connected to the gas temperature sensor 23, the solenoid valve 24, and the buffer tank 25. The end of the buffer tank 25 away from the solenoid valve 24 is connected to the hydrogen inlet of the fuel cell stack 6. The coolant flowing through the heater 3 through the first connecting pipe heats the hydrogen in the liquid hydrogen vaporizer 22 and then flows back to the coolant heat exchange system 1 (or the coolant inlet of the fuel cell stack 6) through the second connecting pipe.

[0060] In this embodiment, the first connecting pipe containing the heater 3 is connected to the inlet of the heat exchange pipe of the liquid hydrogen vaporizer 22, while the second connecting pipe is connected to the outlet of the heat exchange pipe of the liquid hydrogen vaporizer 22. Hydrogen flows through the hydrogen pipe of the liquid hydrogen vaporizer 22, which is connected to both the hydrogen inlet and outlet of the liquid hydrogen vaporizer 22. The heat exchange pipe and the hydrogen pipe exchange heat (e.g., the hydrogen pipe is built into the heat exchange pipe, the heat exchange pipe is built into the hydrogen pipe, or the heat exchange pipe and hydrogen pipe are stacked on top of each other), allowing the coolant to circulate between the liquid hydrogen vaporizer 22 and the coolant heat exchange system 1 to generate heat exchange. To improve heat exchange efficiency, the flow direction of the coolant in the heat exchange pipe is opposite to the flow direction of the hydrogen in the hydrogen pipe. Heat exchange efficiency can also be ensured by extending the contact time between the coolant and / or hydrogen (e.g., by lengthening the heat exchange path between them).

[0061] Please see Figure 1 As shown in the specific embodiments of the present invention, the coolant heat exchange system 1 includes a small circulation cooling system 11 (hereinafter referred to as small circulation) and a large circulation cooling system 12 (hereinafter referred to as large circulation). When the fuel cell system is started, the small circulation cooling system 11 is adapted to rapidly raise the stack temperature to a suitable operating temperature range (+60℃~+80℃). After the stack temperature in the fuel cell system reaches the operating temperature range, the large circulation cooling system 12 is adapted to cool and circulate the high-temperature coolant flowing out of the stack 6 back to the stack 6.

[0062] Please see Figure 1 As shown in the specific embodiment of the present invention, the small-circuit cooling system 11 includes a cooling water pump 111, a first electric heater 112, a thermostat 113, and a three-way valve 114. The inlet of the cooling water pump 111 is connected to the coolant drain port of the fuel cell stack 6, so that part of the coolant exiting the cooling water pump 111 flows to the first electric heater 112 or the large-circuit cooling system 12. The other end of the first electric heater 112 is connected to the F inlet of the thermostat 113. The E outlet of the thermostat 113 is connected to the A inlet of the three-way valve 114, and the B outlet of the three-way valve 114 is connected to the coolant inlet of the fuel cell stack 6. The remaining coolant exiting the cooling water pump 111 flows to the heater 3 through the first connecting pipe, and the C inlet of the three-way valve 114 is connected to the second connecting pipe.

[0063] When the fuel cell system is first turned on, in order to quickly raise the temperature of the stack 6 to the appropriate operating temperature range (+60℃~+80℃), the small circulation cooling system 11 is activated. The coolant flowing out of the stack 6 passes through the cooling water pump 111, the first electric heater 112, the F inlet and E outlet of the thermostat 113 (the D inlet of the thermostat is closed at this time), the A inlet and B outlet of the three-way valve 114, and finally flows into the stack 6.

[0064] In practical applications, when the fuel cell system is started up in a low-temperature environment (below 0°C), the coolant flowing into the fuel cell stack 6 is heated by the first electric heater 112. At this time, the coolant heat exchange system 1 operates as a small-circulation cooling system 11, ensuring that the temperature of the fuel cell stack 6 reaches at least above 0°C. When the temperature of the fuel cell stack 6 reaches above 0°C, the temperature of the coolant flowing out of the fuel cell stack 6 is lower than the set temperature and cannot provide enough heat to allow the liquid hydrogen to absorb heat and vaporize into gaseous hydrogen that meets the hydrogen set temperature of the downstream PEM fuel cell (i.e., fuel cell stack 6). By starting the heater 3, the coolant flowing into the liquid hydrogen vaporizer 22 from the cooling water pump 111 is heated so that it can exchange heat with the liquid hydrogen flowing through the spiral coil (hydrogen pipeline) of the liquid hydrogen vaporizer 22, so that the liquid hydrogen can be fully vaporized into gaseous hydrogen that meets the hydrogen set temperature of the downstream fuel cell stack 6.

[0065] Furthermore, when the fuel cell system experiences a "short shutdown and restart", both the large and small circulation loops of the coolant heat exchange system 1 are closed. The heater 3 can utilize the characteristic that "liquid hydrogen needs to absorb heat to vaporize into gaseous hydrogen" to utilize the high-temperature coolant flowing out of the fuel cell stack 6. Therefore, under this condition, it is not necessary to open the large and small circulation loops. Only the circulation loop where the heater 3 is located needs to be opened, which reduces the energy consumption of the cooling circulation system in the fuel cell system and improves the energy utilization rate of the entire vehicle.

[0066] In addition, the liquid hydrogen vaporizer 22 is equipped with a spiral coil. Cryogenic liquid hydrogen flows from the liquid hydrogen bottle 21 into the spiral coil inside the liquid hydrogen vaporizer 22. The coolant flowing out of the fuel cell stack 6 passes through the cooling water pump 111, heater 3, liquid hydrogen vaporizer 22, and the C inlet of the three-way valve 114, and finally merges with the small / large circulating coolant at the B outlet of the three-way valve 114 before flowing into the fuel cell stack 6.

[0067] It should be noted that the fuel cell coolant circulates in the space between the inner wall of the liquid hydrogen vaporizer 22 and the spiral coil (i.e., the heat exchange pipeline). The flow direction of the liquid hydrogen is opposite to that of the fuel cell coolant. During this process, heat exchange occurs between the two, causing the liquid hydrogen to absorb heat and vaporize into gaseous hydrogen that meets the hydrogen set temperature of the downstream fuel cell system. At the same time, the high-temperature coolant flowing into the liquid hydrogen vaporizer 22 is transformed into a low-temperature coolant, reducing the heat load, especially in the large circulation, and saving thermal management energy consumption of the fuel cell stack 6.

[0068] Please see Figure 1 As shown, in some embodiments of the present invention, the large-circulation cooling system 12 includes a radiator 121 and a particulate filter 122, and a portion of the coolant flowing into the large-circulation cooling system 12 flows sequentially through the radiator 121, the particulate filter 122 and the D inlet of the thermostat 113.

[0069] In other embodiments of the present invention, the large circulation cooling system 12 further includes an expansion tank 123 and a deionizer 124. A portion of the coolant flowing into the large circulation cooling system 12 flows sequentially through the deionizer 124, the expansion tank 123, and the cooling water pump 111; while the expansion tank 123 is connected to the exhaust port of the fuel cell stack 6.

[0070] When the temperature of the fuel cell stack in the fuel cell system reaches the appropriate operating temperature range (+60℃~+80℃), the large-circulation cooling system 12 is activated. The high-temperature coolant flowing out of the fuel cell stack 6 passes through the cooling water pump 111, radiator 121 (electric fan + heat sink), particulate filter 122, thermostat 113's D inlet and E outlet (at this time, thermostat 113's F inlet is closed, i.e., the small circulation is closed), and three-way valve 114's A inlet and B outlet, and finally flows into the fuel cell stack 6.

[0071] Please see Figure 1 As shown in the specific embodiments of the present invention, the vehicle-mounted liquid hydrogen vaporization hydrogen supply system further includes a hydrogen buffer system 7, which includes a pressure relief valve 71 and an emission protector 72 connected in sequence for releasing hydrogen pressure.

[0072] By setting up a buffer tank 25, a certain amount of gaseous hydrogen is stored in the buffer tank 25 to meet the hydrogen demand when the fuel cell system is first started. If the hydrogen pressure inside the buffer tank 25 is close to the allowable pressure of the tank itself (i.e., the maximum working pressure), the pressure relief valve 71 will automatically open to release the hydrogen pressure according to the pre-set action pressure threshold. The released hydrogen is discharged into the air through the emission protector 72 to avoid safety accidents such as deformation or even rupture of the tank due to excessive pressure inside the buffer tank 25.

[0073] Furthermore, in some embodiments of the present invention, the second connecting pipe, the coolant inlet of the fuel cell stack 6, and the coolant outlet of the fuel cell stack 6 are all equipped with temperature sensors 4 to detect the temperature of the coolant. In this embodiment, the temperature difference between the coolant entering the fuel cell stack 6 and exiting the fuel cell stack 6 (e.g., around 10 degrees Celsius) is controlled by detecting the coolant inlet temperature, the coolant outlet temperature, and the coolant outlet temperature of the hydrogen vaporizer 22. This ensures the stable operation of the fuel cell stack 6. Simultaneously, the ratio, flow rate, and flow of coolant flowing from the large / small circulation to the hydrogen vaporizer 22 are controlled by the coolant outlet temperature, coolant inlet temperature, and coolant outlet temperature. This control includes (e.g., controlling the opening of the C inlet of the three-way valve 114, the opening of the D / F inlets of the thermostat 113, and the opening of each outlet of the four-way valve connected to the cooling water pump 111, the first connecting pipe, the first electric heater 112, and the radiator 121, i.e., adjusting the ratio of coolant flowing into the large / small circulation and the heater 3), the opening and closing of the heater 3, and the adjustment of the heating energy level). This ensures the temperature linkage regulation between the fuel cell stack 6 and hydrogen, meeting their respective thermal management requirements.

[0074] Please see Figure 1 As shown, in this specific embodiment, the temperature sensor 4 is connected to the second connecting pipe between the hydrogen supply heat exchange system 2 and the coolant heat exchange system 1 to measure the temperature of the coolant flowing into the coolant heat exchange system 1 in the second connecting pipe.

[0075] Please see Figure 1 As shown in the specific embodiment of the present invention, the on-board liquid hydrogen vaporization hydrogen supply system further includes a hydrogen regulation system 8 connected between the buffer tank 25 and the fuel cell stack 6. The hydrogen regulation system 8 includes a filter 81, a hydrogen pressure sensor 82, a pressure regulating valve 83, a hydrogen inlet solenoid valve 84, and a proportional valve 85 connected in sequence. The side of the filter 81 furthest from the hydrogen pressure sensor 82 is connected to the buffer tank 25, and the side of the proportional valve 85 furthest from the hydrogen inlet solenoid valve 84 is connected to the hydrogen inlet of the fuel cell stack 6.

[0076] In addition, when the fuel cell system is started up in a low-temperature environment (below 0°C), the on-board liquid hydrogen vaporization hydrogen supply system operates as follows:

[0077] It is particularly important to note that the electrochemical reaction between hydrogen and air entering stack 6 produces water. In low-temperature environments below 0°C, this residual water easily freezes on the surface of the membrane electrode assembly, hindering the gaseous reaction medium from reaching the catalyst layer for reaction (and potentially causing irreversible performance degradation of the PEM fuel cell). Furthermore, under conditions such as purging or stack 6 operation, excessively low hydrogen flow into stack 6 can actually absorb heat, leading to or even exacerbating the aforementioned phenomenon.

[0078] The fuel cell coolant flowing into the stack 6 is heated by the heater 3. At this time, the small circulation cooling system 11 of the coolant heat exchange system 1 is running, with the aim of ensuring that the temperature of the stack 6 reaches at least above 0°C.

[0079] When the temperature of stack 6 reaches above 0°C, the temperature of the fuel cell coolant flowing out of stack 6 is lower than the set temperature, and it cannot provide enough heat to allow the liquid hydrogen to absorb heat and vaporize into gaseous hydrogen that meets the hydrogen set temperature of the downstream fuel cell (i.e., stack 6).

[0080] At this point, heater 3 needs to be activated to heat the fuel cell coolant flowing from cooling water pump 111 into liquid hydrogen vaporizer 22, so that it can exchange heat with the liquid hydrogen in the spiral coil flowing through liquid hydrogen vaporizer 22, so that the liquid hydrogen can be fully vaporized into gaseous hydrogen that meets the hydrogen set temperature of the downstream fuel cell.

[0081] Please see Figure 1 As shown in the specific embodiments of the present invention, the vehicle-mounted liquid hydrogen vaporization hydrogen supply system also includes a liquid hydrogen system controller 5, which is connected to the coolant heat exchange system 1, the hydrogen supply heat exchange system 2 and the heater 3 respectively. Specifically, the liquid hydrogen system controller 5 is electrically connected to the heater 3, temperature sensor 4, gas temperature sensor 23, solenoid valve 24 and three-way valve 114 and other components.

[0082] Therefore, the liquid hydrogen system controller 5 is electrically connected to the coolant heat exchange system 1, the hydrogen supply heat exchange system 2, the heater 3, the gas temperature sensor 23, and the temperature sensor 4, and is used to monitor and provide feedback on information such as the temperature and pressure changes of liquid hydrogen vaporization into gaseous hydrogen and the temperature changes of the fuel cell circulating coolant.

[0083] When the coolant flowing from the coolant heat exchange system 1 into the hydrogen supply heat exchange system 2 is below a certain temperature, the liquid hydrogen system controller 5 starts the heater 3 to heat the coolant flowing into the hydrogen supply heat exchange system 2, so that the liquid hydrogen in the hydrogen supply heat exchange system 2 is vaporized into hydrogen at the set temperature of the fuel cell stack 6.

[0084] It should be noted that within the fuel cell system, hydrogen and oxygen undergo an electrochemical reaction, generating electricity while also producing heat. To prevent excessively high or low temperatures from affecting the performance of the fuel cell system, a coolant heat exchange system 1 is used to regulate the temperature, ensuring it remains within the optimal operating temperature range (+60℃~+80℃).

[0085] In addition, the operation of the fuel cell system requires a large supply of gaseous hydrogen. The vaporization of liquid hydrogen into gaseous hydrogen requires the absorption of heat. The heat generated by the fuel cell system during the reaction process can serve as the energy source for the vaporization of liquid hydrogen. The hydrogen heat exchange system 2 is suitable for absorbing heat from the liquid hydrogen and vaporizing it into hydrogen at a set temperature that meets the requirements of the fuel cell system under the heat exchange action of the fuel cell coolant.

[0086] When the fuel cell system is shut down for an extended period (e.g., overnight), a startup purging process is required before restarting it to return to normal operation. During startup, hydrogen is used to purge the anode circuit to remove impurities that have seeped into the anode circuit during the shutdown phase. At this time, the temperature of the fuel cell coolant flowing out of stack 6 is lower than the set temperature, and it cannot provide enough heat to allow the liquid hydrogen to absorb heat and vaporize into gaseous hydrogen that meets the set temperature of the downstream PEM fuel cell system.

[0087] At this point, heater 3 needs to be activated to heat the fuel cell coolant flowing from coolant heat exchange system 1 into hydrogen supply heat exchange system 2, so that it can exchange heat with the liquid hydrogen flowing through hydrogen supply heat exchange system 2, so that the liquid hydrogen can be fully vaporized into gaseous hydrogen that meets the hydrogen set temperature of the downstream PEM fuel cell system.

[0088] By setting up a liquid hydrogen system controller 5, a gas temperature sensor 23 and a solenoid valve 24 are installed on the hydrogen outlet side of the liquid hydrogen vaporizer 22. The gas temperature sensor 23 is responsible for monitoring the temperature of the gaseous hydrogen after liquid hydrogen vaporization and feeding the signal back to the liquid hydrogen system controller 5. The solenoid valve 24 is normally open and can be closed to cut off the hydrogen supply when necessary.

[0089] By setting a three-way valve 114, the temperature of the circulating coolant water and the temperature of the vaporized hydrogen in the hydrogen heat exchange system 2 are dynamically adjusted. Based on the temperature value fed back by the gas temperature sensor 23, the upper or lower limit of the pre-set hydrogen temperature threshold is compared, and the liquid hydrogen system controller 5 will issue the following instructions according to the severity level:

[0090] If the temperature value fed back by the gas temperature sensor 23 is slightly low, the liquid hydrogen system controller 5 will send a command to the heater 3 to heat the fuel cell circulating coolant flowing into the liquid hydrogen vaporizer 22 (the purpose is to increase the temperature of the circulating coolant). At the same time, based on the water temperature at the outlet of the circulating coolant in the liquid hydrogen vaporizer 22 fed back by the temperature sensor 4, the opening of the C inlet of the three-way valve 114 will be appropriately increased to increase the flow rate of the circulating coolant.

[0091] In special circumstances (such as when the temperature of the gaseous hydrogen after liquid hydrogen vaporization is too low, when the liquid hydrogen is not completely vaporized, or when a gas-liquid mixture occurs), the temperature value fed back by the gas temperature sensor 23 has reached the lower limit of the pre-set hydrogen temperature threshold. In order to avoid damaging the downstream fuel cell system, the liquid hydrogen system controller 5 sends a command to the solenoid valve 24 to close the solenoid valve 24 and cut off the hydrogen supply.

[0092] If the temperature value reported by the gas temperature sensor 23 is slightly high, the liquid hydrogen system controller 5 will send a command to the heater 3, requiring the heater 3 to stop working. At the same time, based on the water temperature at the outlet of the circulating coolant in the liquid hydrogen vaporizer 22 reported by the temperature sensor 4, the opening of the C inlet of the three-way valve 114 will be appropriately reduced to reduce the flow rate of the circulating coolant.

[0093] When the fuel cell system is running stably at high power for a long time, the fuel cell cooling circulation system is the large-circulation cooling system 12. When the fuel cell system experiences a "short shutdown and restart", there is a relatively high temperature coolant inside the stack 6, while there is a relatively low temperature coolant in the radiator 121 (electronic fan + heat sink). There is a difference in the amount of coolant radiation between the two. If the relatively low temperature coolant in the radiator 121 (electronic fan + heat sink) is allowed to directly enter the stack 6, it will cause a strong thermal shock to the stack 6, which may cause deformation of the bipolar plates of the stack 6 or "flooding" due to condensed water vapor.

[0094] To address the flooding issue, the on-board liquid hydrogen vaporization hydrogen supply system in this embodiment of the invention utilizes the characteristic that "liquid hydrogen needs to absorb heat to vaporize into gaseous hydrogen." When the fuel cell system experiences a "short shutdown and restart," the thermostat 113 can be closed (equivalent to both the large and small circulations of the fuel cell cooling system being closed). Simultaneously, the high-temperature coolant from the fuel cell stack 6 flows out, passes through the cooling water pump 111, heater 3, and liquid hydrogen vaporizer 22, and completes the heat exchange with the liquid hydrogen. Subsequently, it passes through the temperature sensor 4, the C inlet of the three-way valve 114, the B outlet of the three-way valve 114, and finally flows into the fuel cell stack 6.

[0095] While avoiding thermal shock damage to fuel cell stack 6, it can also reduce the energy consumption of radiator 121 (electronic fan + water tank).

[0096] Another embodiment of the present invention provides an on-board liquid hydrogen vaporization hydrogen supply control method, applied to the above-described on-board liquid hydrogen vaporization hydrogen supply system, the on-board liquid hydrogen vaporization hydrogen supply control method comprising:

[0097] During the thermal management of the coolant heat exchange system 1 for the fuel cell stack 6 and the hydrogen supply heat exchange system 2, the following steps are performed;

[0098] Obtain the hydrogen inlet temperature of hydrogen-into-pile 6;

[0099] When the hydrogen inlet temperature is lower than the hydrogen set temperature of stack 6, the following steps are executed:

[0100] The heater 3, which is installed in the first connecting pipe, is started to heat the coolant flowing through it until the hydrogen entering the stack after heat exchange with it meets the hydrogen set temperature of the stack 6.

[0101] Furthermore, the thermal management of the coolant heat exchange system 1 for the fuel cell stack 6 and the hydrogen supply heat exchange system 2 specifically includes the following steps:

[0102] S1: When the fuel cell system is started, the small circulation cooling system 11 of the coolant heat exchange system 1 works, which makes the temperature of the stack 6 rise rapidly to the operating temperature range; during this period, part of the coolant exiting the stack 6 flows to the hydrogen supply heat exchange system 2 to exchange heat with hydrogen, and the remaining part flows to the large circulation cooling system 12, and finally merges and flows to the coolant inlet of the stack 6.

[0103] S2: When the temperature of the fuel cell stack 6 reaches the operating temperature range, the large circulation cooling system 12 of the coolant heat exchange system 1 starts to circulate and cool the high-temperature coolant flowing out of the fuel cell stack 6; during this period, part of the coolant flowing out of the fuel cell stack 6 flows to the hydrogen supply heat exchange system 2 to exchange heat with hydrogen, and the remaining part flows to the large circulation cooling system 12, and finally flows to the coolant inlet of the fuel cell stack 6.

[0104] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. An on-vehicle liquid hydrogen gasification hydrogen supply system characterized by comprising: include: A coolant heat exchange system (1) is connected to the coolant inlet and outlet of the fuel cell stack (6). The coolant heat exchange system (1) includes a small-circulation cooling system (11) and a large-circulation cooling system (12). The small-circulation cooling system (11) is adapted to rapidly raise the temperature of the fuel cell stack (6) to the operating temperature range when the fuel cell system is turned on. The large-circulation cooling system (12) is adapted to cool and circulate the high-temperature coolant flowing out of the fuel cell stack (6) back to the fuel cell stack (6) after the temperature of the fuel cell stack (6) reaches the operating temperature range. The small-circulation cooling system (11) includes a cooling water pump (111), a first electric heater (112), a thermostat (113), and a three-way valve (114). The inlet of the cooling water pump (111) is connected to the coolant drain port of the fuel cell stack (6), so that part of the coolant from the cooling water pump (111) flows to the first electric heater (112) or the large-circulation cooling system (12). The other end of the first electric heater (112) is connected to the F inlet of the thermostat (113). The E outlet of the thermostat (113) is connected to the A inlet of the three-way valve (114), and the B outlet of the three-way valve (114) is connected to the coolant inlet of the fuel cell stack (6). A hydrogen supply heat exchange system (2) includes a liquid hydrogen vaporizer (22), the hydrogen supply heat exchange system (2) being connected to the hydrogen inlet of the fuel cell stack (6), and the hydrogen supply heat exchange system (2) being connected to the coolant heat exchange system (1) so that the coolant of the coolant heat exchange system (1) and the hydrogen of the hydrogen supply heat exchange system (2) exchange heat; and A heater (3) is installed in a first connecting pipe for connecting the hydrogen supply heat exchange system (2) and the coolant heat exchange system (1) to heat the coolant flowing from the coolant heat exchange system (1) to the hydrogen supply heat exchange system (2), so as to realize the heat exchange between the coolant and hydrogen to raise the temperature of the hydrogen to reach the set temperature of hydrogen entering the fuel cell stack (6); the coolant after heat exchange with hydrogen flows back to the coolant heat exchange system (1) through a second connecting pipe. The coolant flowing through the heater (3) via the first connecting pipe is heated to hydrogen in the liquid hydrogen vaporizer (22) and then flows back to the coolant heat exchange system (1) via the second connecting pipe. Part of the coolant from the fuel cell stack (6) flows through the heater (3) via the first connecting pipe and, after being heated to hydrogen, flows through the second connecting pipe to exchange heat with the remaining part of the coolant from the fuel cell stack (6) and then flows back to the coolant heat exchange system (1) to exchange heat and then flows to the coolant inlet of the fuel cell stack (6). The remaining coolant from the cooling water pump (111) flows to the heater (3) through the first connecting pipe, and the C inlet of the three-way valve (114) is connected to the second connecting pipe.

2. The on-board liquid hydrogen gasification hydrogen supply system according to claim 1, characterized by, The hydrogen supply heat exchange system (2) also includes a liquid hydrogen cylinder (21) for storing liquid hydrogen, a gas temperature sensor (23), a solenoid valve (24) and a buffer tank (25). The hydrogen inlet of the liquid hydrogen vaporizer (22) is connected to the liquid hydrogen cylinder (21), and the hydrogen outlet of the liquid hydrogen vaporizer (22) is connected in sequence to the gas temperature sensor (23), the solenoid valve (24) and the buffer tank (25). The end of the buffer tank (25) away from the solenoid valve (24) is connected to the hydrogen inlet of the fuel cell stack (6).

3. The on-board liquid hydrogen vaporization hydrogen supply system according to claim 1, characterized in that: The large-circulation cooling system (12) includes a radiator (121) and a particulate filter (122). A portion of the coolant flowing into the large-circulation cooling system (12) sequentially flows through the radiator (121), the particulate filter (122), and the D inlet of the thermostat (113); and / or, The large-circulation cooling system (12) also includes an expansion tank (123) and a deionizer (124). A portion of the coolant flowing into the large-circulation cooling system (12) flows sequentially through the deionizer (124), the expansion tank (123), and the cooling water pump (111). The expansion tank (123) is connected to the exhaust port of the fuel cell stack (6).

4. The vehicle-mounted liquid hydrogen vaporization hydrogen supply system according to claim 2, characterized in that: It also includes a hydrogen buffer system (7) connected to the end of the buffer tank (25), the hydrogen buffer system (7) comprising a pressure relief valve (71) and a discharge protector (72) connected in sequence; and / or, Temperature sensors (4) are provided in the second connecting pipe, the coolant inlet of the fuel cell stack (6), and the coolant outlet of the fuel cell stack (6) to detect the temperature of the coolant.

5. The on-board liquid hydrogen vaporization hydrogen supply system according to claim 2, characterized in that, It also includes a hydrogen regulation system (8) connected between the buffer tank (25) and the fuel cell stack (6). The hydrogen regulation system (8) includes a filter (81), a hydrogen pressure sensor (82), a pressure regulating valve (83), a hydrogen inlet solenoid valve (84), and a proportional valve (85) connected in sequence. The filter (81) is connected to the buffer tank (25) on the side away from the hydrogen pressure sensor (82), and the proportional valve (85) is connected to the hydrogen inlet of the fuel cell stack (6) on the side away from the hydrogen inlet solenoid valve (84).

6. A method for controlling on-board liquid hydrogen vaporization hydrogen supply, applied to the on-board liquid hydrogen vaporization hydrogen supply system as described in any one of claims 1-5, characterized in that, During the thermal management of the coolant heat exchange system (1) for the fuel cell stack (6) and the hydrogen supply heat exchange system (2), the following steps are performed: Obtain the hydrogen inlet temperature of the fuel cell (6); When the hydrogen inlet temperature is lower than the hydrogen set temperature of the fuel cell stack (6), the following steps are performed: The heater (3) installed in the first connecting pipe is started to heat the coolant flowing through it until the hydrogen entering the stack after heat exchange with it meets the hydrogen set temperature of the stack (6).

7. The on-board liquid hydrogen vaporization hydrogen supply control method according to claim 6, characterized in that, The thermal management of the coolant heat exchange system (1) for the fuel cell stack (6) and the hydrogen supply heat exchange system (2) specifically includes the following steps: S1: When the fuel cell system is started, the small circulation cooling system (11) of the coolant heat exchange system (1) works, causing the temperature of the fuel cell stack (6) to rise rapidly to the operating temperature range; and during this period, part of the coolant flowing out of the fuel cell stack (6) flows to the hydrogen supply heat exchange system (2) to exchange heat with hydrogen, and the remaining part flows to the small circulation cooling system (11), and finally flows to the coolant inlet of the fuel cell stack (6); S2: When the temperature of the fuel cell stack (6) reaches the operating temperature range, the large circulation cooling system (12) of the coolant heat exchange system (1) is activated to circulate and cool the high-temperature coolant flowing out of the fuel cell stack (6); during this period, part of the coolant flowing out of the fuel cell stack (6) flows to the hydrogen supply heat exchange system (2) to exchange heat with hydrogen, and the remaining part flows to the large circulation cooling system (12), and finally flows to the coolant inlet of the fuel cell stack (6).

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