Asymmetric multi-stack fuel cell system and control method therefor

Abstract

The present application relates to the technical field of fuel cell stacks, and discloses an asymmetric multi-stack fuel cell system and a control method therefor. The system comprises a hydrogen supply system, a low-power fuel cell stack, a high-power fuel cell stack, an air supply system, a first circulation system, a second circulation system, a thermal management system, and a combined discharge system. According to the present application, a remaining unreacted gas mixture in the reaction process of the low-power fuel cell stack and the high-power fuel cell stack can be recirculated, thereby improving energy utilization efficiency. Furthermore, the thermal management system enables the asymmetric fuel cell stack of the present application to be effectively started and operated even in a special environment, thereby improving the overall temperature adaptability of a fuel cell system in application scenarios, without relying on the charging and discharging of a power battery to assist startup of the fuel cell stack.

Description

An asymmetric multi-stack fuel cell system and its control method Technical Field

[0001] This application relates to the field of fuel cell stack technology, and in particular to an asymmetric multi-stack fuel cell system and its control method. Background Technology

[0002] Against the backdrop of global efforts to "peak carbon" and "carbon neutrality," traditional fossil fuels are gradually being replaced by clean energy sources to reduce carbon emissions. As an emerging clean energy source, hydrogen energy plays a crucial role in the recent energy revolution due to its advantages such as low carbon emissions, high energy conversion efficiency, and ease of use. Fuel cell systems, as a primary pathway for hydrogen utilization, can directly convert the chemical energy of fuels (commonly hydrogen) and oxidants (usually oxygen or air) into electrical energy through electrochemical reactions.

[0003] As fuel cell system technology matures and its applications expand, several issues have emerged that limit its widespread adoption. Currently, fuel cell systems often require a power battery for startup, with the battery's charging and discharging assisting in the system's operation. However, in low-temperature environments, such as below 0°C, the power battery's charging and discharging characteristics are poor, or even nonexistent. This significantly reduces the overall temperature adaptability of the fuel cell system, preventing effective startup in certain scenarios. Another existing problem is the resource waste caused by insufficient energy utilization during fuel cell stack operation. Summary of the Invention

[0004] This application provides an asymmetric multi-stack fuel cell system and its control method, which can improve the overall temperature adaptability of the fuel cell system in the application scenario, and improve the energy utilization rate by recycling the unreacted mixed gas in the low-power fuel cell stack and the high-power fuel cell stack through the first circulation system and the second circulation system.

[0005] In one aspect of this application, an asymmetric multi-stack fuel cell system is provided, the asymmetric multi-stack fuel cell system including a hydrogen supply system 100, a low-power fuel cell stack 401, a high-power fuel cell stack 403, an air supply system 200, a first circulation system 300, a second circulation system 400, a thermal management system 500, and a mixed exhaust system 600.

[0006] The hydrogen supply system 100 is connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403 respectively. The hydrogen supply system 100 is used to supply hydrogen that meets the first preset conditions to the low-power fuel cell stack 401 and the high-power fuel cell stack 403.

[0007] The air supply system 200 is connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403 respectively. The air supply system 200 is used to provide air that meets the second preset conditions to the low-power fuel cell stack 401 and the high-power fuel cell stack 403.

[0008] The first circulation system 300 is connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the air supply system 200 and the mixing system 600 respectively. The first circulation system 300 is used to circulate and transport the hydrogen emitted by the low-power fuel cell stack 401 and the high-power fuel cell stack 403 to the high-power fuel cell stack 403.

[0009] The second circulation system 400 is connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the hydrogen supply system 100 and the mixing system 600 respectively. The second circulation system 400 is used to circulate and transport the mixed gas containing liquid water emitted by the low-power fuel cell stack 401 to the high-power fuel cell stack 403.

[0010] The thermal management system 500 is connected to the high-power fuel cell stack 403, and the thermal management system 500 is used to provide the high-power fuel cell stack 403 with coolant that meets the third preset conditions.

[0011] Optionally, the hydrogen supply system 100 includes a first integrated temperature and pressure sensor 107 and a hydrogen storage cylinder 101, a cylinder valve 102, a pressure reducing valve 103, a safety valve 104, a hydrogen heat exchanger 105, and a first proportional valve 106 connected in sequence; the first proportional valve 106 is connected to the inlet of the low-power fuel cell stack 401, and the first integrated temperature and pressure sensor 107 is located in the connecting pipeline between the first proportional valve 106 and the low-power fuel cell stack 401.

[0012] Optionally, the hydrogen supply system 100 further includes a second proportional valve 113, an ejector 114, and a second integrated temperature and pressure sensor 116; the second proportional valve 113 is connected to the hydrogen heat exchanger 105 and the ejector 114, the ejector 114 is connected to the inlet of the high-power fuel cell stack 403, and the second integrated temperature and pressure sensor 116 is located in the connecting pipeline between the ejector 114 and the high-power fuel cell stack 403.

[0013] Optionally, the first circulation system 300 includes a fifth integrated temperature and pressure sensor 108, a first gas-liquid separator 109, a first nitrogen discharge valve 110, a first check valve 112, a hydrogen saving valve 115, a sixth integrated temperature and pressure sensor 117, a second gas-liquid separator 118, and a second check valve 119.

[0014] The outlet of the low-power fuel cell stack 401, the first gas-water separator 109, the first nitrogen discharge valve 110, the first one-way valve 112 and the ejector 114 are connected in sequence, and the fifth integrated temperature and pressure sensor 108 is located in the connecting pipeline between the low-power fuel cell stack 401 and the first gas-water separator 109.

[0015] The outlet of the high-power fuel cell stack 403, the second gas-water separator 118, the second one-way valve 119 and the ejector 114 are connected in sequence, and the sixth integrated temperature and pressure sensor 117 is located in the connecting pipeline between the high-power fuel cell stack 403 and the second gas-water separator 118.

[0016] The hydrogen-saving valve 115 is located in the connecting pipeline between the inlet of the high-power fuel cell stack 403 and the first one-way valve 112. The hydrogen-saving valve 115 is used to adjust the hydrogen concentration at the inlet of the high-power fuel cell stack 403.

[0017] Hydrogen emitted from the outlet of the low-power fuel cell stack 401 and hydrogen emitted from the outlet of the high-power fuel cell stack 403 are ejected by the ejector 114 to the inlet of the high-power fuel cell stack 403.

[0018] Optionally, the first circulation system 300 further includes a first drain valve 111, a second nitrogen discharge valve 120, and a second drain valve 121. The first drain valve 111 is located in the connecting pipeline between the first gas-liquid separator 109 and the mixing system 600. The second nitrogen discharge valve 120 and the second drain valve 121 are both connected to the second gas-liquid separator 118 and the mixing system 600.

[0019] The liquid water obtained by the first gas-water separator 109 from separating the gas-water mixture emitted by the low-power fuel cell stack 401 is discharged to the mixing system 600 through the first drain valve 111.

[0020] The nitrogen obtained by the second gas-water separator 118 from separating the gas-water mixture emitted by the high-power fuel cell stack 403 is discharged to the mixing system 600 through the second nitrogen discharge valve 120.

[0021] The liquid water obtained by the second gas-water separator 118 from the gas-water mixture emitted by the high-power fuel cell stack 403 is discharged to the mixing system 600 through the second drain valve 121.

[0022] Optionally, the air supply system 200 includes a third integrated temperature and pressure sensor 206 and a first air filter 201, a first air flow meter 202, a blower 203, a first throttle valve 204, and a first humidifier 205 connected in sequence.

[0023] The first humidifier 205 is connected to the inlet of the low-power fuel cell stack 401, the third integrated temperature and pressure sensor 206 is located in the connecting pipe between the first humidifier 205 and the low-power fuel cell stack 401, and the first air filter 201 is used to access air from the atmosphere.

[0024] The air supply system 200 also includes a fourth integrated temperature and pressure sensor 218 and a second air filter 212, a second air flow meter 213, an air compressor 214, an intercooler 215, a second throttle valve 216, and a second humidifier 217 connected in sequence. The second humidifier 217 is connected to the inlet of the high-power fuel cell stack 403. The fourth integrated temperature and pressure sensor 218 is located in the connecting pipe between the second humidifier 217 and the high-power fuel cell stack 403. The second air filter 212 is used to access air from the atmosphere.

[0025] Optionally, the second circulation system 400 includes a seventh integrated temperature and pressure sensor 207, a first back pressure valve 208, a third gas-water separator 209, a humidification valve 210, a third one-way valve 211, an eighth integrated temperature and pressure sensor 219, a second back pressure valve 220, and a bypass valve 221.

[0026] The seventh integrated temperature and pressure sensor 207 is located between the outlet of the low-power fuel cell stack 401 and the first humidifier 205, and the eighth integrated temperature and pressure sensor 219 is located between the outlet of the high-power fuel cell stack and the second humidifier 217.

[0027] The outlet of the low-power fuel cell stack 401 is sequentially connected to the first humidifier 205, the third gas-water separator 209, the humidifier valve 210, the third check valve 211 and the inlet of the high-power fuel cell stack 401, so as to circulate the mixed gas emitted by the low-power fuel cell stack 401 to the high-power fuel cell stack 403.

[0028] The outlet of the low-power fuel cell stack 401 is sequentially connected to the first humidifier 205, the first back pressure valve 208, and the mixing system 600.

[0029] The outlet of the high-power fuel cell stack 403 is sequentially connected to the second humidifier 217, the second back pressure valve 220, and the mixing system 600.

[0030] The bypass valve 221 is connected to the air cooler 215, the second throttle valve 216, and the mixing system 600.

[0031] Optionally, the thermal management system 500 includes a water pump 301, a ninth integrated temperature and pressure sensor 302, a tenth integrated temperature and pressure sensor 303, a thermostat 304, a PTC heater 305, a heat dissipation device 306, a particulate filter 307, an ion filter 308, and an expansion tank 309.

[0032] The outlet of the high-power fuel cell stack 403, the tenth integrated temperature and pressure sensor 303, the thermostat 304, the heat dissipation device 306, the expansion tank 309, the ion filter 308, the water pump 301, the ninth integrated temperature and pressure sensor 302, and the inlet of the high-power fuel cell stack 403 are connected in sequence to form a first circulation loop.

[0033] The outlet of the high-power fuel cell stack 403, the tenth integrated temperature and pressure sensor 303, the PTC heater 305, the water pump 301, the ninth integrated temperature and pressure sensor 302, and the inlet of the high-power fuel cell stack 403 are connected in sequence to form a second circulation loop.

[0034] The outlet of the high-power fuel cell stack 403, the tenth integrated temperature and pressure sensor 303, the heat dissipation device 306, the particulate filter 307, the water pump 301, the ninth integrated temperature and pressure sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a third circulation loop.

[0035] Optionally, the asymmetric multi-stack fuel cell system further includes a first DC-DC converter 402 and a second DC-DC converter 404;

[0036] The second DC-DC converter 404 is electrically connected to the high-power fuel cell stack 403, and is also electrically connected to the air compressor 214, the water pump 301, and the PTC heater 305.

[0037] The first DC-DC converter 402 is used to be electrically connected to the power battery to charge and discharge the power battery;

[0038] The first DC-DC converter 402 is electrically connected to the low-power fuel cell stack 401, and is also electrically connected to the blower 203 and the second DC-DC converter 404, so as to supply power to the blower through the electrical energy generated by the low-power fuel cell stack 401 and to supply power to the air compressor 214, the water pump 301 and the PTC heater 305 through the second DC-DC converter 404.

[0039] The second DC-DC converter 404 is also electrically connected to the power battery for discharging the power battery;

[0040] The second DC-DC converter 404 is also used to transmit the electrical energy generated by the high-power fuel cell stack 403 to the air compressor 214, the water pump 301 and the PTC heater 305.

[0041] According to one aspect of the embodiments of this application, a control method for an asymmetric multi-stall fuel cell system is provided, the method being applied to the aforementioned asymmetric multi-stall fuel cell system, the method comprising:

[0042] Acquire the first monitoring parameters of the first temperature and pressure integrated sensor and the third temperature and pressure integrated sensor;

[0043] Determine whether to start operating the low-power fuel cell stack based on the first monitoring parameter;

[0044] After the low-power fuel cell stack starts operating, the first input current parameter of the low-power fuel cell stack is acquired;

[0045] Determine whether to start the thermal management system based on the input current parameters;

[0046] After the thermal management system starts operating, the second monitoring parameters of the tenth temperature and pressure integrated sensor and the fourth temperature and pressure integrated sensor are acquired;

[0047] Determine whether to start operating the high-power fuel cell stack based on the second monitoring parameter;

[0048] After the high-power fuel cell stack starts operating, the second input current parameter of the high-power fuel cell stack is acquired;

[0049] The success of the asymmetric multi-stack fuel cell system is determined based on the second input current parameter.

[0050] The embodiments of this application include at least the following beneficial effects: According to the asymmetric multi-stack fuel cell system and control method provided in this application, hydrogen emitted by the small-power fuel cell stack and the large-power fuel cell stack is circulated and transported to the large-power fuel cell stack through a first circulation system, and a mixed gas containing liquid water emitted by the small-power fuel cell stack is circulated and transported to the large-power fuel cell stack through a second circulation system. This allows the unreacted mixed gas remaining in the small-power fuel cell stack and the large-power fuel cell stack during the reaction process to be recycled, thereby improving energy utilization.

[0051] Furthermore, by using a thermal management system, the asymmetric fuel cell stack of this application can also be effectively started and operated under special environments, thereby improving the overall temperature adaptability of the fuel cell system in the application scenario, without relying on the charging and discharging of the power battery to assist the start-up of the fuel cell stack. Attached Figure Description

[0052] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0053] Figure 1 is an overall block diagram of the asymmetric fuel cell stack system provided in an embodiment of this application;

[0054] Figure 2 is a detailed structural diagram of the asymmetric fuel cell stack system provided in the embodiment of this application;

[0055] Figure 3 is a power supply schematic diagram of the asymmetric fuel cell stack system provided in the embodiment of this application;

[0056] Figure 4 is a schematic diagram of the startup process of the asymmetric fuel cell stack system provided in the embodiment of this application;

[0057] Figure 5 is a schematic diagram of the idle speed control process of the asymmetric fuel cell stack system provided in the embodiment of this application;

[0058] Figure 6 is another structural schematic diagram of the asymmetric fuel cell stack system provided in the embodiment of this application;

[0059] Figure 7 is another structural schematic diagram of the asymmetric fuel cell stack system provided in the embodiments of this application.

[0060] The attached diagram shows a hydrogen supply system 100; a hydrogen storage cylinder 101; a cylinder valve 102; a pressure reducing valve 103; a safety valve 104; and a hydrogen heat exchanger 105. First proportional valve 106; First integrated temperature and pressure sensor 107; Fifth integrated temperature and pressure sensor 108; First gas-liquid separator 109; First nitrogen discharge valve 110; First drain valve 111; First check valve 112; Second proportional valve 113; Ejector 114; Hydrogen-saving valve 115; Second integrated temperature and pressure sensor 116; Sixth integrated temperature and pressure sensor 117; Second gas-liquid separator 118; Second check valve 119; Second nitrogen discharge valve 120; Second drain valve 121; Air supply system 200; First air filter 201; First air flow meter 202; Blower 203; First throttle valve 204; First humidifier 205; Third integrated temperature and pressure sensor 206; Seventh integrated temperature and pressure sensor 207; First back pressure valve 208; Third gas-liquid separator 209; Humidifier valve 210; Third check valve 211; Second air filter 212; Second air flow meter 213; Air compressor; 214; Intercooler; 215; Second throttle valve; 216; Second humidifier; 217; Fourth integrated temperature and pressure sensor; 218; Eighth integrated temperature and pressure sensor; 219; Second back pressure valve; 220; Bypass valve; 221; Third drain valve; 222; First circulation system; 300; Water pump; 301; Ninth integrated temperature and pressure sensor; 302; Tenth integrated temperature and pressure sensor; 303; Thermostat; 304; PTC heater; 305; Heat dissipation device; 306; Particulate filter; 307; Ion filter; 308; Expansion tank; 309; Second circulation system; 400; Small-power fuel cell stack; 401; First DC-DC converter; 402; High-power fuel cell stack; 403; Second DC-DC converter; 404; Power battery; 405; Third DC-DC converter; 406; Thermal management system; 500; Mixing pipe; 501; Silencer; Mixing system; 600. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0062] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various concepts, but unless otherwise stated, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the words “if,” “when,” or “in response to a determination” as used herein may be interpreted as “when…” or “when…” or “in response to a determination.”

[0063] As used in this application, the terms "at least one", "multiple", "each", "any", etc., "at least one" includes one, two or more, "multiple" includes two or more, "each" refers to each of the corresponding multiples, and "any" refers to any one of the multiples.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0065] The purpose of this application is to provide an asymmetric multi-stack fuel cell system and its control method, which mainly addresses the following issues: First, it solves the uncertainty in power battery selection during fuel cell system installation; second, it addresses the difficulty of power battery discharge in low-temperature environments, reducing the fuel cell system's dependence on power batteries; third, it improves the hydrogen utilization rate of the fuel cell system during low-power operation by using unreacted hydrogen from the anode outlet of the low-power fuel cell system as a secondary hydrogen source to supply the high-power fuel cell system, thereby improving the hydrogen utilization rate of the asymmetric fuel cell system.

[0066] In one aspect of this application, an asymmetric multi-stack fuel cell system is provided, the asymmetric multi-stack fuel cell system including a hydrogen supply system 100, a low-power fuel cell stack 401, a high-power fuel cell stack 403, an air supply system 200, a first circulation system 300, a second circulation system 400, a thermal management system 500, and a mixed exhaust system 600.

[0067] The hydrogen supply system 100 is connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403 respectively. The hydrogen supply system 100 is used to supply hydrogen that meets the first preset conditions to the low-power fuel cell stack 401 and the high-power fuel cell stack 403.

[0068] The air supply system 200 is connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403 respectively. The air supply system 200 is used to provide air that meets the second preset conditions to the low-power fuel cell stack 401 and the high-power fuel cell stack 403.

[0069] The first circulation system 300 is connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the air supply system 200 and the mixing system 600 respectively. The first circulation system 300 is used to circulate and transport the hydrogen emitted by the low-power fuel cell stack 401 and the high-power fuel cell stack 403 to the high-power fuel cell stack 403.

[0070] The second circulation system 400 is connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the hydrogen supply system 100 and the mixing system 600 respectively. The second circulation system 400 is used to circulate and transport the mixed gas containing liquid water emitted by the low-power fuel cell stack 401 to the high-power fuel cell stack 403.

[0071] The thermal management system 500 is connected to the high-power fuel cell stack 403, and the thermal management system 500 is used to provide the high-power fuel cell stack 403 with coolant that meets the third preset conditions.

[0072] Figure 1 shows the overall block diagram of the asymmetric fuel cell stack system. A first circulation system recycles hydrogen emitted from both the low-power and high-power fuel cell stacks to the high-power fuel cell stack. A second circulation system recycles a mixture of gases, including liquid water, emitted from the low-power fuel cell stack to the high-power fuel cell stack. This allows for the recycling of unreacted gases remaining during the reaction process in both stacks, improving energy efficiency. During the circulation of the first and second circulation systems, separated gases, such as nitrogen and liquid water, can be discharged into the mixing system, while only useful hydrogen and high-humidity air are supplied to the high-power fuel cell stack.

[0073] Figure 2 shows a schematic diagram of the specific structure of the asymmetric multi-stacking fuel cell system proposed in this application. The asymmetric multi-stacking fuel cell system includes: a hydrogen storage tank 101; a tank valve 102; a pressure reducing valve 103; a safety valve 104; a hydrogen heat exchanger 105; a first proportional valve 106; a first integrated temperature and pressure sensor 107; a fifth integrated temperature and pressure sensor 108; a first gas-liquid separator 109; a first nitrogen venting valve 110; a first drain valve 111; a first check valve 112; a second proportional valve 113; an ejector 114; a hydrogen-saving valve 115; a second integrated temperature and pressure sensor 116; a sixth integrated temperature and pressure sensor 117; a second gas-liquid separator 118; a second check valve 119; a second nitrogen venting valve 120; a second drain valve 121; a first air filter 201; a first air flow meter 202; a blower 203; a first throttle valve 204; a first humidifier 205; a third integrated temperature and pressure sensor 206; a seventh integrated temperature and pressure sensor 207; a fifth integrated temperature and pressure sensor 208; a sixth integrated temperature and pressure sensor 209; a second nitrogen venting valve 110; a second nitrogen venting valve 120; a second drain valve 121; a first air filter 201; a first air flow meter 202; a blower 203; a first throttle valve 204; a first humidifier 205; a third integrated temperature and pressure sensor 206; a seventh integrated temperature and pressure sensor 207; a fifth integrated temperature and pressure sensor 208; a sixth integrated temperature and pressure sensor 209; a second integrated temperature and pressure sensor 200; a sixth integrated temperature and pressure sensor 201; a second integrated 07; First back pressure valve 208; Third air-water separator 209; Humidifier valve 210; Third check valve 211; Second air filter 212; Second air flow meter 213; Air compressor 214; Intercooler 215; Second throttle valve 216; Second humidifier 217; Fourth integrated temperature and pressure sensor 218; Eighth integrated temperature and pressure sensor 219; Second back pressure valve 220; Bypass valve 221; Third drain valve 222; Water pump 301; Ninth integrated temperature and pressure sensor Device 302; Tenth integrated temperature and pressure sensor 303; Thermostat 304; PTC heater 305; Heat dissipation device 306; Particulate filter 307; Ion filter 308; Expansion tank 309; Small-power fuel cell stack 401; First DC-DC converter 402; High-power fuel cell stack 403; Second DC-DC converter 404; Power battery 405; Third DC-DC converter 406; Mixing pipe 501; Silencer 502.

[0074] Furthermore, the hydrogen supply system 100 includes a first integrated temperature and pressure sensor 107 and a hydrogen storage cylinder 101, a cylinder valve 102, a pressure reducing valve 103, a safety valve 104, a hydrogen heat exchanger 105, and a first proportional valve 106 connected in sequence; the first proportional valve 106 is connected to the inlet of the low-power fuel cell stack 401, and the first integrated temperature and pressure sensor 107 is located in the connecting pipeline between the first proportional valve 106 and the low-power fuel cell stack 401.

[0075] Specifically, the first integrated temperature and pressure sensor 107, along with the sequentially connected hydrogen storage cylinder 101, cylinder valve 102, pressure reducing valve 103, safety valve 104, hydrogen heat exchanger 105, and first proportional valve 106, constitute a hydrogen supply pipeline to the small-power fuel cell stack. In this embodiment, the inlet of the small-power fuel cell stack 401 is the anode inlet. It should be noted that both the small-power and high-power fuel cell stacks in Figure 2 are equipped with multiple inlets and outlets, each corresponding to a different input substance. For example, some inlets input hydrogen, while others input coolant. The function of each inlet differs depending on the input substance. Furthermore, the arrows in Figure 2 indicate the direction of substance transport. For instance, the arrow pointing from the first proportional valve 106 to the inlet of the small-power fuel cell stack 401 indicates that hydrogen can only enter and not exit; the direction of the arrow represents the flow direction of the substance.

[0076] The hydrogen storage cylinder 101 has its outlet connected to the inlet of the cylinder valve 102. Its function is to store high-pressure hydrogen, such as hydrogen at 35 MPa or 70 MPa. The first preset condition characterizes the hydrogen supplied to the low-power fuel cell stack 401 and the high-power fuel cell stack 403 as having suitable flow rate and pressure. Under different operating conditions, the first preset condition will change accordingly. That is, after inputting hydrogen that meets the first preset condition, the low-power fuel cell stack 401 and the high-power fuel cell stack 403 will not experience any risk due to excessively low or high hydrogen pressure.

[0077] The outlet of the bottle valve 102 is connected to the inlet of the pressure reducing valve 103. It typically integrates temperature and pressure sensors to monitor the temperature and pressure of the hydrogen storage cylinder 101.

[0078] The pressure reducing valve 103 has its outlet connected to the inlet of the safety valve 104. Its function is to reduce the pressure of high-pressure hydrogen in the hydrogen storage cylinder 101 to the target supply pressure, typically controlling the downstream pressure between 0.6 MPa and 1.5 MPa according to system requirements.

[0079] The safety valve 104 has its outlet connected to the inlet of the hydrogen heat exchanger 105. Its function is to prevent the hydrogen supply pressure from being too high.

[0080] The hydrogen heat exchanger 105 has its outlet connected to the inlet of the proportional valve 106, with a three-way pipe between them. Its function is to regulate the temperature of hydrogen entering the low-power fuel cell stack 401.

[0081] The first proportional valve 106 has its outlet connected to the hydrogen inlet of the low-power fuel cell stack 401, and a temperature and pressure integrated sensor 107 is arranged near its outlet. Its function is to regulate the hydrogen pressure entering the low-power fuel cell stack 401 under different operating conditions.

[0082] Furthermore, the hydrogen supply system 100 also includes a second proportional valve 113, an ejector 114, and a second integrated temperature and pressure sensor 116; the second proportional valve 113 is connected to the hydrogen heat exchanger 105 and the ejector 114, the ejector 114 is connected to the inlet of the high-power fuel cell stack 403, and the second integrated temperature and pressure sensor 116 is located in the connecting pipeline between the ejector 114 and the high-power fuel cell stack 403.

[0083] Specifically, the hydrogen storage cylinder 101, the cylinder valve 102, the pressure reducing valve 103, the safety valve 104, the hydrogen heat exchanger 105, the second proportional valve 113, and the ejector 114 constitute the hydrogen supply loop from the hydrogen supply system to the high-power fuel cell stack. Of course, the ejector's function is not limited to this; it is also used to eject the hydrogen separated from the first circulation system back into the high-power fuel cell stack.

[0084] The first circulation system 300 includes a fifth integrated temperature and pressure sensor 108, a first gas-liquid separator 109, a first nitrogen discharge valve 110, a first check valve 112, a hydrogen saving valve 115, a sixth integrated temperature and pressure sensor 117, a second gas-liquid separator 118, and a second check valve 119.

[0085] The outlet of the low-power fuel cell stack 401, the first gas-water separator 109, the first nitrogen discharge valve 110, the first one-way valve 112 and the ejector 114 are connected in sequence, and the fifth integrated temperature and pressure sensor 108 is located in the connecting pipeline between the low-power fuel cell stack 401 and the first gas-water separator 109.

[0086] The outlet of the high-power fuel cell stack 403, the second gas-water separator 118, the second one-way valve 119 and the ejector 114 are connected in sequence, and the sixth integrated temperature and pressure sensor 117 is located in the connecting pipeline between the high-power fuel cell stack 403 and the second gas-water separator 118.

[0087] The hydrogen-saving valve 115 is located in the connecting pipeline between the inlet of the high-power fuel cell stack 403 and the first one-way valve 112. The hydrogen-saving valve 115 is used to adjust the hydrogen concentration at the inlet of the high-power fuel cell stack 403.

[0088] Hydrogen emitted from the outlet of the low-power fuel cell stack 401 and hydrogen emitted from the outlet of the high-power fuel cell stack 403 are ejected by the ejector 114 to the inlet of the high-power fuel cell stack 403.

[0089] Optionally, the first circulation system 300 further includes a first drain valve 111, a second nitrogen discharge valve 120, and a second drain valve 121. The first drain valve 111 is located in the connecting pipeline between the first gas-liquid separator 109 and the mixing system 600. The second nitrogen discharge valve 120 and the second drain valve 121 are both connected to the second gas-liquid separator 118 and the mixing system 600.

[0090] The liquid water obtained by the first gas-water separator 109 from separating the gas-water mixture emitted by the low-power fuel cell stack 401 is discharged to the mixing system 600 through the first drain valve 111.

[0091] The nitrogen obtained by the second gas-water separator 118 from separating the gas-water mixture emitted by the high-power fuel cell stack 403 is discharged to the mixing system 600 through the second nitrogen discharge valve 120.

[0092] The liquid water obtained by the second gas-water separator 118 from the gas-water mixture emitted by the high-power fuel cell stack 403 is discharged to the mixing system 600 through the second drain valve 121.

[0093] Specifically, the first gas-water separator 109 has its inlet connected to the hydrogen outlet of the low-power fuel cell stack 401, and a fifth integrated temperature and pressure sensor 108 is arranged near its outlet. Its function is to reduce the water content of the unreacted hydrogen discharged from the low-power fuel cell stack 401.

[0094] The first nitrogen venting valve 110 has its inlet connected to the outlet of the first gas-water separator 109 for venting nitrogen, and its outlet connected to the inlet of the first one-way valve 112. Its function is to maintain the hydrogen concentration in the hydrogen chamber of the low-power fuel cell stack 401.

[0095] The first drain valve 111 has its inlet connected to the outlet of the first gas-water separator 109 for discharging liquid water, and its outlet connected to the mixing pipe 501. Its function is to discharge the liquid water separated by the first gas-water separator 109.

[0096] The second proportional valve 113 has its inlet connected to a three-way pipe between the hydrogen heat exchanger 105 and the first proportional valve 106. Its function is to regulate the hydrogen pressure entering the high-power fuel cell stack 403 under different operating conditions.

[0097] The ejector 114 has three inlets, which are connected to a three-way pipe near the outlet of one-way valve 112, the outlet of one-way valve 119, and the outlet of proportional valve 113, respectively. Its outlet is connected to the hydrogen inlet of the high-power fuel cell stack 403, and a temperature and pressure integrated sensor 116 is arranged between them. Its function is to eject unreacted hydrogen discharged from the low-power fuel cell stack 401 and the high-power fuel cell stack 403, thereby increasing the hydrogen utilization rate of the system.

[0098] The hydrogen-saving valve 115 has its inlet connected to a three-way pipe arranged between the first one-way valve 112 and the ejector 114, and its outlet connected to a three-way pipe arranged between the ejector 114 and the hydrogen inlet of the high-power fuel cell stack 403. When the low-power fuel cell stack 401 is working and the high-power fuel cell stack is not working, the hydrogen-saving valve 115 is open, using the exhaust heat of the low-power fuel cell stack to maintain the temperature of the high-power fuel cell stack. In addition, the interface upstream of the hydrogen-saving valve 115 that connects to the ejector 114 has a very small diameter and cannot be used as a regular pipeline to support a large flow of exhaust gas. The hydrogen-saving valve 115 can only be closed when both the low-power and high-power fuel cell stacks are working simultaneously, using the ejection capability of the ejector 114 to conduct.

[0099] The second gas-water separator 118 has its inlet connected to the hydrogen outlet of the high-power fuel cell stack 403, and a sixth integrated temperature and pressure sensor 117 is arranged near its outlet. Its function is to reduce the water content of the unreacted hydrogen discharged from the high-power fuel cell stack 403.

[0100] The second nitrogen venting valve 120 has its inlet connected via a three-way pipe to the outlet of the second gas-water separator 118 (used for venting nitrogen) and the inlet of the second one-way valve 119. Its function is to maintain the hydrogen concentration in the hydrogen chamber of the high-power fuel cell stack 403.

[0101] The second drain valve 121 has its inlet connected to the outlet of the second gas-water separator 118 for discharging liquid water, and its outlet connected to the mixing pipe 501 via a tee pipe. Its function is to discharge the liquid water separated by the first gas-water separator 109.

[0102] The air supply system 200 includes a third integrated temperature and pressure sensor 206 and a first air filter 201, a first air flow meter 202, a blower 203, a first throttle valve 204, and a first humidifier 205 connected in sequence.

[0103] The first humidifier 205 is connected to the inlet of the low-power fuel cell stack 401, the third integrated temperature and pressure sensor 206 is located in the connecting pipe between the first humidifier 205 and the low-power fuel cell stack 401, and the first air filter 201 is used to access air from the atmosphere.

[0104] The air supply system 200 also includes a fourth integrated temperature and pressure sensor 218 and a second air filter 212, a second air flow meter 213, an air compressor 214, an intercooler 215, a second throttle valve 216, and a second humidifier 217 connected in sequence. The second humidifier 217 is connected to the inlet of the high-power fuel cell stack 403. The fourth integrated temperature and pressure sensor 218 is located in the connecting pipe between the second humidifier 217 and the high-power fuel cell stack 403. The second air filter 212 is used to access air from the atmosphere.

[0105] The second circulation system 400 includes a seventh integrated temperature and pressure sensor 207, a first back pressure valve 208, a third gas-water separator 209, a humidification valve 210, a third one-way valve 211, an eighth integrated temperature and pressure sensor 219, a second back pressure valve 220, and a bypass valve 221.

[0106] The seventh integrated temperature and pressure sensor 207 is located between the outlet of the low-power fuel cell stack 401 and the first humidifier 205, and the eighth integrated temperature and pressure sensor 219 is located between the outlet of the high-power fuel cell stack and the second humidifier 217.

[0107] The outlet of the low-power fuel cell stack 401 is sequentially connected to the first humidifier 205, the third gas-water separator 209, the humidifier valve 210, the third check valve 211 and the inlet of the high-power fuel cell stack 401, so as to circulate the mixed gas emitted by the low-power fuel cell stack 401 to the high-power fuel cell stack 403.

[0108] The outlet of the low-power fuel cell stack 401 is sequentially connected to the first humidifier 205, the first back pressure valve 208, and the mixing system 600.

[0109] The outlet of the high-power fuel cell stack 403 is sequentially connected to the second humidifier 217, the second back pressure valve 220, and the mixing system 600.

[0110] The bypass valve 221 is connected to the air cooler 215, the second throttle valve 216, and the mixing system 600.

[0111] Specifically, the first air filter 201 has its inlet connected to the atmosphere. Its function is to filter impurities in the air that are harmful to the small fuel cell stack.

[0112] The blower 203 has its inlet connected to the outlet of the first air filter 201, and a first air flow meter 202 is arranged between the two to monitor the flow rate of air supplied to the low-power fuel cell stack 401.

[0113] The inlet of the first throttle valve 204 is connected to the outlet of the blower 203.

[0114] The first humidifier 205 has a dry-side inlet, a dry-side outlet, a wet-side inlet, and a wet-side outlet. Its dry-side inlet is connected to the outlet of the throttle valve 204; its wet-side inlet is connected to the air outlet of the low-power fuel cell stack 401, and a seventh integrated temperature and pressure sensor 207 is arranged between the two; its dry-side outlet is connected to the air inlet of the low-power fuel cell stack 401, and a third integrated temperature and pressure sensor 206 is arranged between the two; its wet-side outlet is connected to the inlet of the first back pressure valve 208 via a three-way pipe.

[0115] The first back pressure valve 208 has its inlet connected to a tee pipe located near the wet-side outlet of the first humidifier 205, and its outlet connected to the mixing pipe 501 via the tee pipe. The first back pressure valve 208 is used to control the flow distribution of the mixed gas emitted by the low-power fuel cell system.

[0116] The second gas-liquid separator 209 has its inlet connected to a tee pipe located near the wet-side outlet of the first humidifier 205. Its function is to reduce the liquid water in the gas-liquid mixture discharged from the low-power fuel cell stack 401.

[0117] The humidification valve 210 has its inlet connected to the exhaust port of the second air-water separator 209, and its outlet connected to the inlet of the third one-way valve 211. Its function is to control the flow rate of high-humidity air entering the high-power fuel cell stack 403. The second preset condition is used to characterize the air entering the low-power fuel cell stack 401 and the high-power fuel cell stack 403 as high-humidity air, with a water content ranging from 60% to 95%.

[0118] The second air filter 212 has its inlet connected to the atmosphere. Its function is to filter impurities in the air that are harmful to the fuel cell stack.

[0119] The air compressor 214 has its inlet connected to the outlet of the second air filter 212, and a second air flow meter 213 is arranged between the two to monitor the flow rate of air supplied to the high-power fuel cell stack 403.

[0120] The intercooler 215 has its air inlet connected to the outlet of the air compressor 214. Its function is to reduce the temperature of the supplied air. Compared to the blower 203, the outlet temperature of the air compressor 214 is higher, necessitating a reduction in the temperature of the supplied air to meet the requirements of the fuel cell stack for the supplied air temperature.

[0121] The second throttle valve 216 has its inlet connected to the air outlet of the intercooler 215 via a three-way pipe.

[0122] The second humidifier 217 also has a dry-side inlet, a dry-side outlet, a wet-side inlet, and a wet-side outlet. Its dry-side inlet is connected to the outlet of the second throttle valve 216; its wet-side inlet is connected to the air outlet of the high-power fuel cell stack 403, and an eighth integrated temperature and pressure sensor 219 is arranged between the two; its dry-side outlet is connected to the air inlet of the high-power fuel cell stack 403 and the outlet of the third one-way valve 211 via a three-way pipe, and a fourth integrated temperature and pressure sensor 218 is arranged near the air inlet of the high-power fuel cell stack 403; its wet-side outlet is connected to the inlet of the first back pressure valve 208.

[0123] The second back pressure valve 220 has its outlet connected to the mixing pipe 501 via a three-way pipe. In order to avoid surge of the humidification valve 210, the second back pressure valve 220 discharges the exhaust gas and generated water of the high-power fuel cell stack 403 to the outside.

[0124] The bypass valve 221 has its inlet connected to a three-way pipe between the air cooler 215 and the second throttle valve 216, and its outlet connected to the mixing pipe 501 via a three-way pipe.

[0125] The thermal management system 500 includes a water pump 301, a ninth integrated temperature and pressure sensor 302, a tenth integrated temperature and pressure sensor 303, a thermostat 304, a PTC heater 305, a heat dissipation device 306, a particulate filter 307, an ion filter 308, and an expansion tank 309.

[0126] The outlet of the high-power fuel cell stack 403, the tenth integrated temperature and pressure sensor 303, the thermostat 304, the heat dissipation device 306, the expansion tank 309, the ion filter 308, the water pump 301, the ninth integrated temperature and pressure sensor 302, and the inlet of the high-power fuel cell stack 403 are connected in sequence to form a first circulation loop.

[0127] The outlet of the high-power fuel cell stack 403, the tenth integrated temperature and pressure sensor 303, the PTC heater 305, the water pump 301, the ninth integrated temperature and pressure sensor 302, and the inlet of the high-power fuel cell stack 403 are connected in sequence to form a second circulation loop.

[0128] The outlet of the high-power fuel cell stack 403, the tenth integrated temperature and pressure sensor 303, the heat dissipation device 306, the particulate filter 307, the water pump 301, the ninth integrated temperature and pressure sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a third circulation loop.

[0129] Specifically, the outlet of the water pump 301 is connected to the coolant inlet of the high-power fuel cell system 403, and a ninth integrated temperature and pressure sensor 302 is arranged between the two. Its function is to regulate the supply pressure and flow rate of the coolant.

[0130] The thermostat 304 is a three-way ball valve with one inlet and two outlets. Its inlet is connected to the coolant outlet of the high-power fuel cell system 403, and a tenth integrated temperature and pressure sensor 303 is arranged between the two. Its function is to regulate the flow distribution of coolant between the first and third circulation loops.

[0131] The PTC heater 305 has its inlet connected to the small circulation outlet of the thermostat 304. Its function is to heat the coolant.

[0132] The heat dissipation device 306 consists of a radiator and a fan, with its coolant inlet connected to the outlet of the thermostat 304. Its function is to control the temperature of the coolant.

[0133] The particulate filter 307 has its inlet connected to the coolant outlet of the radiator and its fan 306. Its function is to filter impurities in the coolant.

[0134] The ion filter 308 has its inlet connected to the water supply port of the expansion tank 309, and its outlet is located upstream of the water pump 301 via a tee pipe. Its function is to reduce the conductivity of the coolant.

[0135] The air inlet of the expansion tank 309 is connected to the exhaust port of the heat dissipation device 306.

[0136] The expansion tank 309 integrates a liquid level sensor, a water inlet, an air inlet, a coolant filling port, and a pressure relief valve. The liquid level sensor identifies the liquid level in the expansion tank 309, preventing insufficient coolant from causing malfunctions in the thermal management system, excessively rapid or excessive temperature rise. The liquid level sensor can be positioned at the bottom or top of the expansion tank 309 depending on the maintenance space. The water inlet should be located as close to the center of the bottom of the expansion tank 309 as possible to avoid the water supply being affected by vehicle tilting during driving. The air inlet of the expansion tank 309 is connected to the exhaust port of the cooling device 306. Multiple air inlets can be provided, connected to the exhaust ports near the coolant outlet of the cooling device 306 and near the coolant outlet of the high-power fuel cell stack 403. The outlet of the pressure relief valve can be directly connected to the ambient atmosphere, and the coolant filling port and pressure relief valve can be integrated into a single valve port according to system requirements.

[0137] Furthermore, the asymmetric multi-stack fuel cell system also includes a first DC-DC converter 402 and a second DC-DC converter 404;

[0138] The second DC-DC converter 404 is electrically connected to the high-power fuel cell stack 403, and is also electrically connected to the air compressor 214, the water pump 301, and the PTC heater 305.

[0139] The first DC-DC converter 402 is used to be electrically connected to the power battery to charge and discharge the power battery;

[0140] The first DC-DC converter 402 is electrically connected to the low-power fuel cell stack 401, and is also electrically connected to the blower 203 and the second DC-DC converter 404, so as to supply power to the blower through the electrical energy generated by the low-power fuel cell stack 401 and to supply power to the air compressor 214, the water pump 301 and the PTC heater 305 through the second DC-DC converter 404.

[0141] The second DC-DC converter 404 is also electrically connected to the power battery for discharging the power battery;

[0142] The second DC-DC converter 404 is also used to transmit the electrical energy generated by the high-power fuel cell stack 403 to the air compressor 214, the water pump 301 and the PTC heater 305.

[0143] The low-power fuel cell stack 401 can be either air-cooled or water-cooled. The embodiment shown in this application demonstrates an air-cooled stack, integrating an air inlet, air outlet, hydrogen inlet, and hydrogen outlet. If a water-cooled stack is used, an additional thermal management system is required, or it may be shared with the thermal management system of the high-power fuel cell stack 403. Furthermore, the high-voltage terminals of the low-power fuel cell stack 401 are connected to the high-voltage terminals of the first DC-DC converter 402.

[0144] As shown in Figure 3, the first DC-DC converter 402 has two high-voltage output terminals. One is connected to the high-voltage power supply port of the blower 203 and provides unidirectional power; the other is connected to the high-voltage power supply port of the second DC-DC converter 404 and provides unidirectional power. Its function is to boost the output voltage of the small-power fuel cell stack 401, thereby meeting the high-voltage power supply requirements of the blower 203, air compressor 214, water pump 301, and PTC heater 305.

[0145] The high-power fuel cell stack 403 integrates an air inlet, an air outlet, a hydrogen inlet, a hydrogen outlet, a coolant inlet, and a coolant outlet. Additionally, an exhaust port can be arranged near the coolant outlet of the high-power fuel cell stack 403. Furthermore, the high-voltage terminals of the high-power fuel cell stack 403 are connected to the high-voltage terminals of the second DC-DC converter 404.

[0146] The second DC-DC converter 404 has four high-voltage output terminals. First, it connects to the high-voltage power supply port of the third DC-DC converter 406 in the power battery, providing unidirectional power. Second, it connects to the high-voltage power supply port of the air compressor 214, providing unidirectional power. Third, it connects to the high-voltage power supply port of the water pump 301, providing unidirectional power. Fourth, it connects to the high-voltage power supply port of the PTC heater 305, providing unidirectional power. Its function is to boost the output voltage of the high-power fuel cell stack 403, thereby meeting the high-voltage power supply requirements of the air compressor 214, water pump 301, PTC heater 305, and DC-DC converter 406.

[0147] The high-voltage terminal of the power battery 405 is connected to the high-voltage terminal of the DC-DC converter 406.

[0148] The third DC-DC converter 406 has its high-voltage input terminal connected to one of the high-voltage output terminals of the DC-DC converter 404, and can use the electricity generated by the high-power fuel cell stack 403 to charge the power battery 405; it can also provide bidirectional power supply to the first DC-DC converter 402, so it can use the power battery 405 for power supply or the electricity generated by the low-power fuel cell stack 401 to charge the power battery 405.

[0149] The muffler 502 is located downstream of the mixing pipe 501, and the mixing pipe 501 and the muffler 502 together form a mixing system 600.

[0150] Existing technical solutions and their shortcomings:

[0151] As fuel cell system technology matures and its applications expand, several challenges have emerged that limit its widespread adoption. Currently, fuel cell systems often require a power battery to assist in startup. However, in low-temperature environments, such as below 0°C, the power battery's discharge characteristics are poor, sometimes even preventing charging and discharging altogether. This significantly reduces the overall temperature adaptability of the fuel cell system in various operating environments. Therefore, effectively reducing the fuel cell system's dependence on the power battery during operation can improve its overall temperature adaptability.

[0152] For fuel cell systems with a rated power of around 100kW, the idle power is typically between 3 and 5kW. The system idle power is generally proportional to the system's rated power; that is, the higher the rated power, the higher the idle power. If the system operates at idle for extended periods, the battery's state of charge (SOC) will become too high, preventing charging, and the idle power will have nowhere to dissipate. Furthermore, in low-temperature environments, such as below 0°C, the battery's allowable charging power is less than the idle power, or the battery may not be allowed to charge at all.

[0153] The technical problem solved by this application is:

[0154] As shown in Figure 3, the power generated by the low-power fuel cell stack 401 supplies power to the blower and the second DC-DC converter 404 supplies power to the air compressor 214, the water pump 301, and the PTC heater 305. The second DC-DC converter 404 is also used to transmit the power generated by the high-power fuel cell stack 403 to the air compressor 214, the water pump 301, and the PTC heater 305. In this way, the thermal management system 500 solves the problem of the power battery's difficulty in discharging in low-temperature environments, reduces the fuel cell system's dependence on the power battery, and improves the uncertainty of power battery selection.

[0155] In this embodiment, the reliance of fuel cell systems lacking self-humidification capabilities on humidifiers can be reduced, effectively decreasing the usage frequency of the first humidifier 205 and the second humidifier 217, thereby reducing power consumption. High-humidity gas from the cathode outlet of a low-power fuel cell system can be used as a humidification source for humidifying a high-power fuel cell system.

[0156] To improve the hydrogen utilization rate of the fuel cell system during low-power operation, unreacted hydrogen from the anode outlet of the low-power fuel cell system can be used as a secondary hydrogen source to supply the high-power fuel cell system, thereby improving the hydrogen utilization rate of the entire fuel cell system.

[0157] According to one embodiment of this application, a control method for an asymmetric multi-stacking fuel cell system is also proposed. The method is applied to the aforementioned asymmetric multi-stacking fuel cell system and includes:

[0158] Acquire the first monitoring parameters of the first temperature and pressure integrated sensor and the third temperature and pressure integrated sensor;

[0159] Determine whether to start operating the low-power fuel cell stack based on the first monitoring parameter;

[0160] After the low-power fuel cell stack starts operating, the first input current parameter of the low-power fuel cell stack is acquired;

[0161] Determine whether to start the thermal management system based on the input current parameters;

[0162] After the thermal management system starts operating, the second monitoring parameters of the tenth temperature and pressure integrated sensor and the fourth temperature and pressure integrated sensor are acquired;

[0163] Determine whether to start operating the high-power fuel cell stack based on the second monitoring parameter;

[0164] After the high-power fuel cell stack starts operating, the second input current parameter of the high-power fuel cell stack is acquired;

[0165] The success of the asymmetric multi-stack fuel cell system is determined based on the second input current parameter.

[0166] Specifically, please refer to Figure 4, which is a flowchart of the control method for an asymmetric multi-stacking fuel cell system, that is, the start-up control process of the asymmetric multi-stacking fuel cell system, as follows:

[0167] Upon power-up, the controller wakes up and enters self-test mode, completing the self-test process (details omitted here). It then checks if a start-up command has been received, i.e., a command to start the fuel cell system. If no start-up command is received, it returns to the self-test process; if a start-up command is received, it controls the actuators of the hydrogen supply system and the air supply system. Specifically, the control of the hydrogen supply system actuators is as follows:

[0168] Open the bottle neck valve 102, adjust the first proportional valve 106, adjust the first nitrogen discharge valve 110, adjust the first drain valve 111, close the second proportional valve 113, open the hydrogen saving valve 115, adjust the second nitrogen discharge valve 120, and adjust the second drain valve 121.

[0169] The control of the actuator corresponding to the air supply system 200 is specifically as follows:

[0170] Adjust the blower 203, open the first throttle valve 204, close the first back pressure valve 208, adjust the humidification valve 210, turn off the air compressor 214, close the second throttle valve 216, adjust the second back pressure valve 220, and close the bypass valve 221.

[0171] At this point, it is determined whether the pressure P107 of the first integrated temperature and pressure sensor 107 (which can be obtained from the first monitoring parameter) is greater than or equal to P1 (here, the value can be 1.15 bar), and whether the pressure P206 of the third integrated temperature and pressure sensor 206 (which can be obtained from the first monitoring parameter) is greater than or equal to P2 (here, the value can be 1.05 bar, or it can be determined by identifying whether the actual positions of the blower 203 and the back pressure valve 208 have reached the target position). If the above two conditions are not met, then wait and return to the previous step; if the above two conditions are met, then the first DC-DC converter 402 can be started. It is determined whether the input current I402 of the first DC-DC converter 402 (i.e., the first input current parameter of the small power fuel cell stack) is greater than or equal to I1 (here, the value can be 10A, or other values ​​less than the idle current), then the thermal management system actuator is controlled to work, and a flag bit indicating successful start-up of the small power fuel cell stack is output.

[0172] The control of the actuators corresponding to the thermal management system 500 specifically includes: adjusting the water pump 301, adjusting the thermostat 304, adjusting the PTC heater 305, and turning off the radiator fan 306. It checks whether the temperature T303 of the tenth temperature and pressure integrated sensor 303 (which can be obtained from the second monitoring parameter) is greater than or equal to T1 (here, the value can be -5℃). If not, it returns to the previous step; if so, it checks whether the requested power W is greater than or equal to the rated power of the small-power fuel cell stack 401 minus the input power of the blower 203 * 1.5. If not, it returns to controlling the thermal management system actuators; if so, it controls the hydrogen supply system actuators, air supply system actuators, and thermal management system actuators. Specifically, the control of the hydrogen system actuators at this time includes opening the bottle valve 102, adjusting the first proportional valve 106, adjusting the first nitrogen venting valve 110, adjusting the first drain valve 111, adjusting the second proportional valve 113, closing the hydrogen-saving valve 115, adjusting the second nitrogen venting valve 120, and adjusting the second drain valve 121.

[0173] The specific control of the hydrogen supply system actuator at this time includes adjusting the blower 203, opening the first throttle valve 204, adjusting the first back pressure valve 208, adjusting the humidification valve 210, adjusting the air compressor 214, opening the second throttle valve 216, adjusting the second back pressure valve 220, and adjusting the bypass valve 221.

[0174] The thermal management system actuator at this time controls the water pump 301, the thermostat 304, the PTC heater 305, and shuts down the radiator fan 306. It checks whether the pressure P116 of the second integrated temperature and pressure sensor 116 is greater than or equal to P3 (which can be 1.15 bar), and whether the pressure P228 of the fourth integrated temperature and pressure sensor 218 (which can be obtained from the second monitoring parameter) is greater than or equal to P4 (which can be 1.05 bar, or by identifying whether the actual positions of the air compressor 214 and the second back pressure valve 220 have reached the target positions). If neither of these conditions is met, it waits and returns to the previous step; if both conditions are met, the second DC-DC converter 404 can be started. It checks whether the input current I404 of the second DC-DC converter 404 (i.e., the second input current parameter of the high-power fuel cell stack) is greater than or equal to I2 (which can be 10 A, or other values ​​less than the idle current). If so, the startup of the asymmetric multi-stack fuel cell system is completed, and a flag indicating successful startup of the low-power fuel cell stack is output.

[0175] Furthermore, the control flow of idle speed control is shown in Figure 5, and the idle speed control flow is as follows:

[0176] Wait and determine whether an idle command has been received. If no idle command is received, continue to wait. If an idle command is received, control the actuators corresponding to the hydrogen supply system 100, the air supply system 200, and the thermal management system 500 to operate.

[0177] Specifically, the control of the actuator corresponding to the hydrogen supply system 100 is as follows:

[0178] Open the bottle neck valve 102, adjust the first proportional valve 106, adjust the first nitrogen discharge valve 110, adjust the first drain valve 111, close the second proportional valve 113, open the hydrogen saving valve 115, adjust the second nitrogen discharge valve 120, and adjust the second drain valve 121.

[0179] The control of the actuator corresponding to the air supply system 200 is specifically as follows:

[0180] Adjust the blower 203, open the first throttle valve 204, close the first back pressure valve 208, adjust the humidification valve 210, turn off the air compressor 214, close the second throttle valve 216, adjust the second back pressure valve 220, and close the bypass valve 221.

[0181] The actuator control corresponding to the thermal management system 500 includes regulating the water pump 301, regulating the thermostat 304, regulating the PTC heater 305, and shutting down the radiator fan 306. At this time, the control work of the hydrogen supply system actuator, air supply system actuator, and thermal management system actuator is completed, outputting the idle operation flag of the small-power fuel cell stack 401 / shutdown flag of the large-power fuel cell stack 403. It checks whether a shutdown command has been received. If no shutdown command is received, the hydrogen supply system actuator, air supply system actuator, and thermal management system actuator continue to operate; if a shutdown command is received, the shutdown process begins. It checks whether the requested power W is greater than or equal to 0. If the check is not valid, the hydrogen supply system actuator, air supply system actuator, and thermal management system actuator continue to operate; if the check is valid, the output current of the small-power fuel cell stack 401 and the large-power fuel cell stack 403 is calculated, and the small-power fuel cell stack 401 and the large-power fuel cell stack 403 are activated, entering the fuel cell system operating state, and continuously checking whether an idle command has been received.

[0182] According to one embodiment of this application, the asymmetric multi-stacking fuel cell system of this application can also be as shown in Figure 6. Figure 6 shows another implementation of the asymmetric multi-stacking fuel cell system of this application. The difference from Figure 2 is that the first humidifier 205 and the second humidifier 217 are omitted in Figure 6. The small-power fuel cell stack 401 in Figure 6 can be a fuel cell stack that does not require external humidification or can self-humidify. Humidification of the high-power fuel cell stack 403 can be achieved simply by adjusting the humidification valve 210 and the third drain valve 222. Controlling the opening of the humidification valve 210 regulates the flow rate of the high-humidity cathode gas entering the high-power fuel cell stack 403 (cathode gas discharged from the small-power fuel cell stack and separated by the gas-water separator 209); controlling the opening of the third drain valve 222 regulates the amount of water stored in the third gas-water separator 209. In addition, reducing two components can effectively reduce the system cost.

[0183] According to one embodiment of this application, the asymmetric multi-stacking fuel cell system of this application can also be shown in Figure 7. Figure 7 shows another implementation of the asymmetric multi-stacking fuel cell system of this application. The difference from Figure 2 is that the first air filter 201 and the blower 203 are omitted in Figure 7. In Figure 7, the air supply to the low-power fuel cell stack 401 is achieved by controlling the air compressor 214 and the first throttle valve 204. Outside air is filtered by the second air filter 212, pressurized by the air compressor 214, cooled by the intercooler 215, and the flow rate is regulated by the first throttle valve 204, and supplied to the low-power fuel cell stack 401. In addition, the calculation of the air flow rate supplied to the high-power fuel cell stack 403 requires the difference between the value of the second air flow meter 213 and the value of the first air flow meter 202. Therefore, reducing two components can reduce the maintenance cost of the system.

[0184] In summary, this application utilizes a first circulation system to recycle hydrogen emitted from both the low-power and high-power fuel cell stacks to the high-power fuel cell stack, and a second circulation system to recycle a mixed gas containing liquid water emitted from the low-power fuel cell stack to the high-power fuel cell stack. This allows the unreacted mixed gas remaining during the reaction process of both the low-power and high-power fuel cell stacks to be recycled, thereby improving energy utilization.

[0185] Furthermore, by using a thermal management system, the asymmetric fuel cell stack of this application can also be effectively started and operated under special environments, thereby improving the overall temperature adaptability of the fuel cell system in the application scenario, without relying on the charging and discharging of the power battery to assist the start-up of the fuel cell stack.

[0186] Furthermore, this solution addresses the uncertainty in power battery selection during fuel cell system integration; resolves the difficulty of power battery discharge in low-temperature environments, reducing the fuel cell system's dependence on power batteries; reduces the dependence of fuel cell systems without self-humidification capabilities on humidifiers by utilizing the high-humidity gas at the cathode outlet of low-power fuel cell systems as a humidification source for high-power fuel cell systems; and improves the hydrogen utilization rate of fuel cell systems operating at low power by using unreacted hydrogen at the anode outlet of low-power fuel cell systems as a secondary hydrogen source to supply high-power fuel cell systems, thereby improving the hydrogen utilization rate of asymmetric fuel cell systems.

[0187] In the foregoing description of this specification, the references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0188] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

[0189] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An asymmetric multi-stack fuel cell system, characterized in that, The asymmetric multi-stack fuel cell system includes a hydrogen supply system (100), a small-power fuel cell stack (401), a high-power fuel cell stack (403), an air supply system (200), a first circulation system (300), a second circulation system (400), a thermal management system (500), and a mixed-displacement system (600). The hydrogen supply system (100) is connected to the low-power fuel cell stack (401) and the high-power fuel cell stack (403) respectively. The hydrogen supply system (100) is used to supply hydrogen that meets the first preset conditions to the low-power fuel cell stack (401) and the high-power fuel cell stack (403). The air supply system (200) is connected to the low-power fuel cell stack (401) and the high-power fuel cell stack (403) respectively. The air supply system (200) is used to provide air that meets the second preset conditions to the low-power fuel cell stack (401) and the high-power fuel cell stack (403). The first circulation system (300) is connected to the low-power fuel cell stack (401), the high-power fuel cell stack (403), the air supply system (200), and the mixing system (600), respectively. The first circulation system (300) is used to circulate and transport the hydrogen emitted by the low-power fuel cell stack (401) and the high-power fuel cell stack (403) to the high-power fuel cell stack (403). The second circulation system (400) is connected to the low-power fuel cell stack (401), the high-power fuel cell stack (403), the hydrogen supply system (100), and the mixing system (600), respectively. The second circulation system (400) is used to circulate and transport the mixed gas containing liquid water emitted by the low-power fuel cell stack (401) to the high-power fuel cell stack (403). The thermal management system (500) is connected to the high-power fuel cell stack (403), and the thermal management system (500) is used to provide the high-power fuel cell stack (403) with coolant that meets the third preset conditions.

2. The asymmetric multi-stack fuel cell system according to claim 1, characterized in that, The hydrogen supply system (100) includes a first integrated temperature and pressure sensor ((107)) and a hydrogen storage cylinder (101), a cylinder valve (102), a pressure reducing valve (103), a safety valve (104), a hydrogen heat exchanger (105), and a first proportional valve (106) connected in sequence. The first proportional valve (106) is connected to the inlet of the small-power fuel cell stack (401), and the first integrated temperature and pressure sensor ((107)) is located in the connecting pipeline between the first proportional valve (106) and the small-power fuel cell stack (401).

3. The asymmetric multi-stack fuel cell system according to claim 2, characterized in that, The hydrogen supply system (100) further includes a second proportional valve (113), an ejector (114), and a second integrated temperature and pressure sensor (116); the second proportional valve (113) is connected to the hydrogen heat exchanger (105) and the ejector (114), the ejector (114) is connected to the inlet of the high-power fuel cell stack (403), and the second integrated temperature and pressure sensor (116) is located in the connecting pipeline between the ejector (114) and the high-power fuel cell stack (403).

4. The asymmetric multi-stack fuel cell system according to claim 3, characterized in that, The first circulation system (300) includes a fifth integrated temperature and pressure sensor (108), a first gas-liquid separator (109), a first nitrogen discharge valve (110), a first check valve (112), a hydrogen saving valve (115), a sixth integrated temperature and pressure sensor (117), a second gas-liquid separator (118), and a second check valve (119); The outlet of the low-power fuel cell stack (401), the first gas-water separator (109), the first nitrogen discharge valve (110), the first one-way valve (112) and the ejector (114) are connected in sequence, and the fifth integrated temperature and pressure sensor (108) is located in the connecting pipeline between the low-power fuel cell stack (401) and the first gas-water separator (109). The outlet of the high-power fuel cell stack (403), the second gas-water separator (118), the second one-way valve (119) and the ejector (114) are connected in sequence, and the sixth integrated temperature and pressure sensor (117) is located in the connecting pipeline between the high-power fuel cell stack (403) and the second gas-water separator (118). The hydrogen-saving valve (115) is located in the connecting pipeline between the inlet of the high-power fuel cell stack (403) and the first one-way valve (112). The hydrogen-saving valve (115) is used to adjust the hydrogen concentration at the inlet of the high-power fuel cell stack (403). Hydrogen emitted from the outlet of the low-power fuel cell stack (401) and hydrogen emitted from the outlet of the high-power fuel cell stack (403) are ejected to the inlet of the high-power fuel cell stack (403) via the ejector (114).

5. The asymmetric multi-stack fuel cell system according to claim 4, characterized in that, The first circulation system (300) further includes a first drain valve (111), a second nitrogen discharge valve (120), and a second drain valve (121). The first drain valve (111) is located in the connecting pipeline between the first gas-liquid separator (109) and the mixing system (600). The second nitrogen discharge valve (120) and the second drain valve (121) are both connected to the second gas-liquid separator (118) and the mixing system (600). The liquid water obtained by the first gas-water separator (109) separating the gas-water mixture emitted by the low-power fuel cell stack (401) is discharged to the mixing system (600) through the first drain valve (111). The nitrogen obtained by the second gas-water separator (118) from separating the gas-water mixture emitted by the high-power fuel cell stack (403) is discharged to the mixing system (600) through the second nitrogen discharge valve (120); The liquid water obtained by the second gas-water separator (118) from the gas-water mixture emitted by the high-power fuel cell stack (403) is discharged to the mixing system (600) through the second drain valve (121).

6. The asymmetric multi-stack fuel cell system according to claim 1, characterized in that, The air supply system (200) includes a third integrated temperature and pressure sensor (206) and a first air filter (201), a first air flow meter (202), a blower (203), a first throttle valve (204), and a first humidifier (205) connected in sequence. The first humidifier (205) is connected to the inlet of the low-power fuel cell stack (401), the third integrated temperature and pressure sensor (206) is located in the connecting pipe between the first humidifier (205) and the low-power fuel cell stack (401), and the first air filter (201) is used to access air from the atmosphere. The air supply system (200) also includes a fourth integrated temperature and pressure sensor (218) and a second air filter (212), a second air flow meter (213), an air compressor (214), an intercooler (215), a second throttle valve (216), and a second humidifier (217) connected in sequence; the second humidifier (217) is connected to the inlet of the high-power fuel cell stack (403), the fourth integrated temperature and pressure sensor (218) is located in the connecting pipe between the second humidifier (217) and the high-power fuel cell stack (403), and the second air filter (212) is used to access air from the atmosphere.

7. The asymmetric multi-stack fuel cell system according to claim 6, characterized in that, The second circulation system (400) includes a seventh integrated temperature and pressure sensor (207), a first back pressure valve (208), a third gas-water separator (209), a humidification valve (210), a third one-way valve (211), an eighth integrated temperature and pressure sensor (219), a second back pressure valve (220), and a bypass valve (221); The seventh integrated temperature and pressure sensor (207) is located between the outlet of the low-power fuel cell stack (401) and the first humidifier (205), and the eighth integrated temperature and pressure sensor (219) is located between the outlet of the high-power fuel cell stack and the second humidifier (217). The outlet of the low-power fuel cell stack (401) is sequentially connected to the first humidifier (205), the third gas-water separator (209), the humidifier valve (210), the third check valve (211), and the inlet of the high-power fuel cell stack (401) to circulate the mixed gas emitted by the low-power fuel cell stack (401) to the high-power fuel cell stack (403); The outlet of the low-power fuel cell stack (401) is sequentially connected to the first humidifier (205), the first back pressure valve (208), and the mixing system (600); The outlet of the high-power fuel cell stack (403) is sequentially connected to the second humidifier (217), the second back pressure valve (220), and the mixing system (600); The bypass valve (221) is connected to the air cooler (215), the second throttle valve (216), and the mixing system (600).

8. The asymmetric multi-stack fuel cell system according to claim 1, characterized in that, The thermal management system (500) includes a water pump (301), a ninth integrated temperature and pressure sensor (302), a tenth integrated temperature and pressure sensor (303), a thermostat (304), a PTC heater (305), a heat dissipation device (306), a particulate filter (307), an ion filter (308), and an expansion tank (309). The outlet of the high-power fuel cell stack (403), the tenth integrated temperature and pressure sensor (303), the thermostat (304), the heat dissipation device (306), the expansion tank (309), the ion filter (308), the water pump (301), the ninth integrated temperature and pressure sensor (302), and the inlet of the high-power fuel cell stack (403) are connected in sequence to form a first circulation loop; The outlet of the high-power fuel cell stack (403), the tenth integrated temperature and pressure sensor (303), the PTC heater (305), the water pump (301), the ninth integrated temperature and pressure sensor (302), and the inlet of the high-power fuel cell stack (403) are connected in sequence to form a second circulation loop; The outlet of the high-power fuel cell stack (403), the tenth integrated temperature and pressure sensor (303), the heat dissipation device (306), the particulate filter (307), the water pump (301), the ninth integrated temperature and pressure sensor (302), and the inlet of the high-power fuel cell stack (403) are sequentially connected to form a third circulation loop.

9. The asymmetric multi-stack fuel cell system according to claim 1, characterized in that, The asymmetric multi-stack fuel cell system also includes a first DC-DC converter (402) and a second DC-DC converter (404); The second DC-DC converter (404) is electrically connected to the high-power fuel cell stack (403), and is also electrically connected to the air compressor (214), the water pump (301), and the PTC heater (305); The first DC-DC converter (402) is used to be electrically connected to the power battery to charge and discharge the power battery; The first DC-DC converter (402) is electrically connected to the low-power fuel cell stack (401), and is also electrically connected to the blower (203) and the second DC-DC converter (404) to supply power to the blower through the electrical energy generated by the low-power fuel cell stack (401) and to supply power to the air compressor (214), the water pump (301), and the PTC heater (305) through the second DC-DC converter (404). The second DC-DC converter (404) is also electrically connected to the power battery for discharging the power battery; The second DC-DC converter (404) is also used to deliver the electrical energy generated by the high-power fuel cell stack (403) to the air compressor (214), the water pump (301) and the PTC heater (305).

10. A control method for an asymmetric multi-stack fuel cell system, characterized in that, The method is applied to the asymmetric multi-stack fuel cell system as described in any one of claims 1-9, and the method includes: Acquire the first monitoring parameters of the first temperature and pressure integrated sensor and the third temperature and pressure integrated sensor; Determine whether to start operating the low-power fuel cell stack based on the first monitoring parameter; After the low-power fuel cell stack starts operating, the first input current parameter of the low-power fuel cell stack is acquired; Determine whether to start the thermal management system based on the input current parameters; After the thermal management system starts operating, the second monitoring parameters of the tenth temperature and pressure integrated sensor and the fourth temperature and pressure integrated sensor are acquired; Determine whether to start operating the high-power fuel cell stack based on the second monitoring parameter; After the high-power fuel cell stack starts operating, the second input current parameter of the high-power fuel cell stack is acquired; The success of the asymmetric multi-stack fuel cell system is determined based on the second input current parameter.

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