Asymmetric multi-stack fuel cell system and control method thereof

Abstract

The invention relates to the technical field of fuel cell stacks, and discloses an asymmetric multi-stack fuel cell system and a control method thereof. 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 circulating system, a second circulating system, a heat management system and a mixed discharging system. According to the application, the residual unreacted mixed gas in the reaction process of the low-power fuel cell stack and the high-power fuel cell stack can be recycled, so that the utilization rate of energy is improved. Furthermore, the asymmetric fuel cell stack can be effectively started and operated in a special environment through a thermal management system, so that the overall temperature adaptability of the fuel cell system in a carrying scene is improved, and the starting of the fuel cell stack does not need to be assisted by charging and discharging of a power cell.

Description

Technical Field

[0001] This application relates to the technical field of fuel cell stacks, and particularly to an asymmetric multi-stack fuel cell system and its control method. Background Art

[0002] Traditional fossil fuels are gradually being replaced by clean energy to reduce carbon emissions. As a new type of clean energy, hydrogen energy plays an important role in the recent energy revolution due to its low carbon emissions, high energy conversion efficiency, and convenient use. Among them, the fuel cell system, as the main way of using hydrogen, can directly convert the chemical energy in fuels (such as hydrogen gas commonly) and oxidants (usually oxygen or air) into electrical energy through electrochemical reactions.

[0003] As the technical maturity of fuel cell systems gets higher and higher, the application scenarios of fuel cell systems are becoming increasingly widespread, but some problems have also emerged that limit their popularization progress. Currently, fuel cell systems often need to be matched with power batteries in the mounting scenarios, and the charging and discharging of power batteries are used to assist the start-up of fuel cell systems. However, in low-temperature environments, such as less than 0°C, the charging and discharging characteristics of power batteries are poor, and even charging and discharging are not allowed, which greatly reduces the overall temperature adaptability of fuel cell systems in mounting scenarios, making fuel cell systems unable to be effectively started in some special scenarios. There are also problems of resource waste caused by insufficient energy utilization rate of fuel cell stacks during operation. Summary of the Invention

[0004] The embodiments of this application provide an asymmetric multi-stack fuel cell system and its control method, which can improve the overall temperature adaptability of fuel cell systems in mounting scenarios, and recycle the unreacted mixed gas in small-power fuel cell stacks and large-power fuel cell stacks through the first circulation system and the second circulation system, thereby improving the energy utilization rate.

[0005] On the one hand, the embodiments of this application provide an asymmetric multi-stack fuel cell system, which includes a hydrogen supply system 100, a small-power fuel cell stack 401, a large-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 mixing and discharging system 600; The hydrogen supply system 100 is respectively connected to the small-power fuel cell stack 401 and the large-power fuel cell stack 403, and the hydrogen supply system 100 is used to provide hydrogen that meets the first preset condition to the small-power fuel cell stack 401 and the large-power fuel cell stack 403; The air supply system 200 is respectively connected to the small-power fuel cell stack 401 and the high-power fuel cell stack 403, and the air supply system 200 is configured to supply air meeting a second preset condition to the small-power fuel cell stack 401 and the high-power fuel cell stack 403; The first circulation system 300 is respectively connected to the small-power fuel cell stack 401, the high-power fuel cell stack 403, the air supply system 200, and the mixed exhaust system 600. The first circulation system 300 is configured to circulate and transport the hydrogen discharged by the small-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 respectively connected to the small-power fuel cell stack 401, the high-power fuel cell stack 403, the hydrogen supply system 100, and the mixed exhaust system 600. The second circulation system 400 is configured to circulate and transport the mixed gas with liquid water discharged by the small-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 configured to supply a coolant meeting a third preset condition to the high-power fuel cell stack 403.

[0006] Optionally, the hydrogen supply system 100 includes a first temperature and pressure integrated sensor 107, and a hydrogen storage bottle 101, a bottle mouth valve 102, a pressure reducing valve 103, a safety valve 104, a hydrogen heat exchanger 105, and a first proportional valve 106 that are connected in sequence; the first proportional valve 106 is connected to the inlet of the small-power fuel cell stack 401, and the first temperature and pressure integrated sensor 107 is arranged in the connection pipeline between the first proportional valve 106 and the small-power fuel cell stack 401.

[0007] Optionally, the hydrogen supply system 100 further includes a second proportional valve 113, an ejector 114, and a second temperature and pressure integrated 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 temperature and pressure integrated sensor 116 is arranged in the connection pipeline between the ejector 114 and the high-power fuel cell stack 403.

[0008] Optionally, the first circulation system 300 includes a fifth temperature and pressure integrated sensor 108, a first gas-water separator 109, a first nitrogen discharge valve 110, a first one-way valve 112, a hydrogen saving valve 115, a sixth temperature and pressure integrated sensor 117, a second gas-water separator 118, and a second one-way 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. The fifth temperature and pressure integrated sensor 108 is arranged 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. The sixth temperature and pressure integrated sensor 117 is arranged 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 arranged 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; Among them, the hydrogen discharged from the outlet of the low-power fuel cell stack 401 and the hydrogen discharged from the outlet of the high-power fuel cell stack 403 are ejected to the inlet of the high-power fuel cell stack 403 through the ejector 114.

[0009] Optionally, the first circulation system 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 arranged in the connecting pipeline between the first gas-water separator 109 and the mixed discharge system 600. Both the second nitrogen discharge valve 120 and the second drain valve 121 are connected to the second gas-water separator 118 and the mixed discharge system 600; Among them, the liquid water obtained by separating the gas-water mixture discharged from the low-power fuel cell stack 401 by the first gas-water separator 109 is discharged to the mixed discharge system 600 through the first drain valve 111; The nitrogen gas obtained by separating the gas-water mixture discharged from the high-power fuel cell stack 403 by the second gas-water separator 118 is discharged to the mixed discharge system 600 through the second nitrogen discharge valve 120; The liquid water obtained by separating the gas-water mixture discharged from the high-power fuel cell stack 403 by the second gas-water separator 118 is discharged to the mixed discharge system 600 through the second drain valve 121.

[0010] Optionally, the air supply system 200 includes a third temperature and pressure integrated 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 temperature and pressure integrated sensor 206 is arranged in the connecting pipeline between the first humidifier 205 and the low-power fuel cell stack 401. The first air filter 201 is used to access the air in the atmosphere; The air supply system 200 further includes a fourth temperature and pressure integrated sensor 218, and a second air filter 212, a second air flowmeter 213, an air compressor 214, an intercooler 215, a second throttle valve 216, and a second humidifier 217 that are connected in sequence. The second humidifier 217 is connected to the inlet of the high-power fuel cell stack 403. The fourth temperature and pressure integrated sensor 218 is arranged in the connecting pipeline between the second humidifier 217 and the high-power fuel cell stack 403. The second air filter 212 is used to access the air in the atmosphere.

[0011] Optionally, the second circulation system 400 includes a seventh temperature and pressure integrated sensor 207, a first back pressure valve 208, a third gas-water separator 209, a humidifying valve 210, a third one-way valve 211, an eighth temperature and pressure integrated sensor 219, a second back pressure valve 220, and a bypass valve 221; The seventh temperature and pressure integrated sensor 207 is arranged between the outlet of the low-power fuel cell stack 401 and the first humidifier 205. The eighth temperature and pressure integrated sensor 219 is arranged 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 humidifying valve 210, the third one-way valve 211, and the inlet of the high-power fuel cell stack 401, so as to circulate and transport the mixed gas discharged 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 mixed exhaust 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 mixed exhaust system 600; The bypass valve 221 is connected to the air cooler 215, the second throttle valve 216, and the mixed exhaust system.

[0012] Optionally, the thermal management system 500 includes a water pump 301, a ninth temperature and pressure integrated sensor 302, a tenth temperature and pressure integrated 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 temperature and pressure integrated sensor 303, the thermostat 304, the heat dissipation device 306, the expansion tank 309, the ion filter 308, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a first circulation loop; The outlet of the high-power fuel cell stack 403, the tenth temperature and pressure integrated sensor 303, the PTC heater 305, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a second circulation loop; The outlet of the high-power fuel cell stack 403, the tenth temperature and pressure integrated sensor 303, the heat dissipation device 306, the particle filter 307, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a third circulation loop.

[0013] Optionally, the asymmetric multi-stack fuel cell system further 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 perform charge and discharge with 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, so as to supply power to the blower through the electric energy generated by the low-power fuel cell stack 401 and 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 to discharge to the power battery; The second DC-DC converter 404 is also used to deliver the electric energy generated by the high-power fuel cell stack 403 to the air compressor 214, the water pump 301, and the PTC heater 305.

[0014] According to one aspect of the embodiments of the present application, a control method for an asymmetric multi-stack fuel cell system is provided. The method is applied to the above asymmetric multi-stack fuel cell system, and the method includes: Obtain the first monitoring parameters of the first temperature and pressure integrated sensor and the third temperature and pressure integrated sensor; Determine whether to control the start of operation of the low-power fuel cell stack according to the first monitoring parameter; After the low-power fuel cell stack starts to operate, obtain the first input current parameter of the low-power fuel cell stack; Determine whether to control the start of operation of the thermal management system according to the input current parameter; After the thermal management system starts to operate, obtain the second monitoring parameters of the tenth temperature and pressure integrated sensor and the fourth temperature and pressure integrated sensor; Determine whether to control the start of operation of the high-power fuel cell stack according to the second monitoring parameter; After the high-power fuel cell stack starts to operate, obtain the second input current parameter of the high-power fuel cell stack; Judge whether the asymmetric multi-stack fuel cell system starts successfully according to the second input current parameter.

[0015] The embodiments of the present application at least include the following beneficial effects: According to an asymmetric multi-stack fuel cell system and its control method provided by the present application, the hydrogen discharged from the low-power fuel cell stack and the high-power fuel cell stack is circulated and transported to the high-power fuel cell stack through the first circulation system, and the mixed gas with liquid water discharged from the low-power fuel cell stack is circulated and transported to the high-power fuel cell stack through the second circulation system, so that the remaining unreacted mixed gas during the reaction of the low-power fuel cell stack and the high-power fuel cell stack can be recycled, improving the utilization rate of energy.

[0016] Furthermore, through the thermal management system, the asymmetric fuel cell stack of the present application can also be effectively started and operated in a special environment, thereby improving the overall temperature adaptability of the fuel cell system in the mounting scenario, without relying on the charging and discharging of the power battery to assist the start of the fuel cell stack. Description of the Drawings

[0017] The drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification. They are used together with the embodiments of the present application to explain the technical solutions of the present application, and do not constitute a limitation to the technical solutions of the present application.

[0018] Figure 1 It is the overall block diagram of the asymmetric fuel cell stack system provided by the embodiments of the present application; Figure 2 It is the specific structure diagram of the asymmetric fuel cell stack system provided by the embodiments of the present application; Figure 3 It is the power supply schematic diagram of the asymmetric fuel cell stack system provided by the embodiments of the present application; Figure 4Schematic diagram of the startup process of the asymmetric fuel cell stack system provided by the embodiment of the present application; Figure 5 Schematic diagram of the idle control process of the asymmetric fuel cell stack system provided by the embodiment of the present application; Figure 6 Another structural schematic diagram of the asymmetric fuel cell stack system provided by the embodiment of the present application; Figure 7 Yet another structural schematic diagram of the asymmetric fuel cell stack system provided by the embodiment of the present application.

[0019] Reference numerals Hydrogen storage bottle 101; bottle neck valve 102; pressure reducing valve 103; safety valve 104; hydrogen heat exchanger 105; first proportional valve 106; first temperature and pressure integrated sensor 107; fifth temperature and pressure integrated sensor 108; first gas-water 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 temperature and pressure integrated sensor 116; sixth temperature and pressure integrated sensor 117; second gas-water separator 118; second check valve 119; second nitrogen discharge valve 120; second drain valve 121; first air filter 201; first air flow meter 202; blower 203; first throttle valve 204; first humidifier 205; third temperature and pressure integrated sensor 206; seventh temperature and pressure integrated sensor 207; first back pressure valve 208; third gas-water separator 209; humidifying 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 temperature and pressure integrated sensor 218; eighth temperature and pressure integrated sensor 219; second back pressure valve 220; bypass valve 221; third drain valve 222; water pump 301; ninth temperature and pressure integrated sensor 302; tenth temperature and pressure integrated sensor 303; thermostat 304; PTC heater 305; heat dissipation device 306; particulate filter 307; ion filter 308; expansion tank 309; low-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. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. When the following description refers 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 the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the appended claims.

[0021] It can be understood that the terms "first", "second", etc. used in the present application may be used in this document to describe various concepts, but unless otherwise specified, 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 the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if", "when" as used herein may be interpreted as "when...", "while...", or "in response to determining".

[0022] The terms "at least one", "a plurality of", "each", "any one", etc. used in the present application, at least one includes one, two or more than two, a plurality includes two or more than two, each refers to each of the corresponding plurality, and any one refers to any one of the plurality.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0024] The objective of the present application is to provide an asymmetric multi-stack fuel cell system and its control method, and the main problems to be solved are as follows: First, to solve the problem of uncertainty in the selection of power batteries during the installation of fuel cell systems; second, to solve the problem of difficult discharge of power batteries in low-temperature environments and reduce the dependence of fuel cell systems on power batteries; third, to improve the hydrogen utilization rate of fuel cell systems during low-power operation, and use the unreacted hydrogen at the anode outlet of a small-power fuel cell system as a secondary hydrogen source to supply a large-power fuel cell system, thereby improving the hydrogen utilization rate of the asymmetric fuel cell system.

[0025] In one aspect of the embodiments of the present application, an asymmetric multi-stack fuel cell system is provided. The asymmetric multi-stack fuel cell system includes 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 mixing and discharging system 600; The hydrogen supply system 100 is respectively connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403. The hydrogen supply system 100 is configured to supply hydrogen meeting a first preset condition to the low-power fuel cell stack 401 and the high-power fuel cell stack 403; The air supply system 200 is respectively connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403. The air supply system 200 is configured to supply air meeting a second preset condition to the low-power fuel cell stack 401 and the high-power fuel cell stack 403; The first circulation system 300 is respectively connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the air supply system 200, and the mixing and discharging system 600. The first circulation system 300 is configured to circulate and transport the hydrogen discharged 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 respectively connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the hydrogen supply system 100, and the mixing and discharging system 600. The second circulation system 400 is configured to circulate and transport the mixed gas with liquid water discharged 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. The thermal management system 500 is configured to supply coolant meeting a third preset condition to the high-power fuel cell stack 403.

[0026] As Figure 1 shown, Figure 1It is the overall block diagram of an asymmetric fuel cell stack system. Through the first circulation system, the hydrogen discharged from the low-power fuel cell stack and the high-power fuel cell stack is circulated and transported to the high-power fuel cell stack, and through the second circulation system, the mixed gas with liquid water discharged from the low-power fuel cell stack is circulated and transported to the high-power fuel cell stack, so that the unreacted mixed gas remaining in the reaction process of the low-power fuel cell stack and the high-power fuel cell stack can be recycled, improving the energy utilization rate. During the circulation process of the first circulation system and the second circulation system, the separated substances such as nitrogen and liquid water can be discharged into the mixed discharge system, and only the useful hydrogen and high-humidity air are sent into the high-power fuel cell stack.

[0027] As Figure 2 shown, Figure 2 It is the specific structural schematic diagram of the asymmetric multi-stack fuel cell system proposed in this application. The asymmetric multi-stack fuel cell system includes: a hydrogen storage bottle 101; a bottle mouth valve 102; a pressure reducing valve 103; a safety valve 104; a hydrogen heat exchanger 105; a first proportional valve 106; a first temperature and pressure integrated sensor 107; a fifth temperature and pressure integrated sensor 108; a first gas-water separator 109; a first nitrogen discharge 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 temperature and pressure integrated sensor 116; a sixth temperature and pressure integrated sensor 117; a second gas-water separator 118; a second check valve 119; a second nitrogen discharge 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 temperature and pressure integrated sensor 206; a seventh temperature and pressure integrated sensor 207; a first back pressure valve 208; a third gas-water separator 209; a humidifying valve 210; a third check valve 211; a second air filter 212; a second air flow meter 213; an air compressor 214; an intercooler 215; a second throttle valve 216; a second humidifier 217; a fourth temperature and pressure integrated sensor 218; an eighth temperature and pressure integrated sensor 219; a second back pressure valve 220; a bypass valve 221; a third drain valve 222; a water pump 301; a ninth temperature and pressure integrated sensor 302; a tenth temperature and pressure integrated sensor 303; a thermostat 304; a PTC heater 305; a heat dissipation device 306; a particulate filter 307; an ion filter 308; an expansion tank 309; a low-power fuel cell stack 401; a first DC-DC converter 402; a high-power fuel cell stack 403; a second DC-DC converter 404; a power battery 405; a third DC-DC converter 406; a mixed discharge pipe 501; a silencer 502.

[0028] Further, the hydrogen supply system 100 includes a first temperature and pressure integrated sensor 107, and a hydrogen storage bottle 101, a bottle valve 102, a pressure reducing valve 103, a safety valve 104, a hydrogen heat exchanger 105, and a first proportional valve 106 that are connected in sequence; the first proportional valve 106 is connected to the inlet of the small power fuel cell stack 401, and the first temperature and pressure integrated sensor 107 is arranged in the connection pipeline between the first proportional valve 106 and the small power fuel cell stack 401.

[0029] Specifically, the first temperature and pressure integrated sensor 107, and the hydrogen storage bottle 101, the bottle valve 102, the pressure reducing valve 103, the safety valve 104, the hydrogen heat exchanger 105, and the first proportional valve 106 that are connected in sequence form 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 Figure 2 both the small power fuel cell stack and the large power fuel cell stack are provided with multiple inlets and outlets, and each inlet and outlet corresponds to different input substances. For example, some inlets input hydrogen, and some inlets input coolant. Corresponding to different input substances, the functions of the inlets are different. At the same time, Figure 2 the arrow directions in Figure 2 represent the conveying directions of substances. For example, the arrow pointing from the first proportional valve 106 to the inlet of the small power fuel cell stack 401 represents that hydrogen can only enter and cannot exit, and the arrow direction represents the flow direction of the substance.

[0030] The hydrogen storage bottle 101 has its outlet connected to the inlet of the bottle valve 102. Its function is to store high-pressure hydrogen, such as hydrogen at 35 MPa or 70 MPa. The first preset condition is used to characterize that the hydrogen supplied to the small power fuel cell stack 401 and the large power fuel cell stack 403 is hydrogen with appropriate flow rate and pressure. Under different working conditions, the first preset condition will change accordingly. That is, after inputting hydrogen that meets the first preset condition, the small power fuel cell stack 401 and the large power fuel cell stack 403 will not have risks due to too low or too high hydrogen pressure.

[0031] The bottle valve 102 has its outlet connected to the inlet of the pressure reducing valve 103. It usually integrates a temperature sensor and a pressure sensor to monitor the temperature and pressure of the hydrogen storage bottle 101.

[0032] The pressure reducing valve 103 has its outlet connected to the inlet of the safety valve 104. Its function is to reduce the high-pressure hydrogen in the hydrogen storage bottle 101 to the target supply pressure, and usually control the downstream pressure between 0.6 MPa and 1.5 MPa according to system requirements.

[0033] The safety valve 104 has its outlet connected to the inlet of the hydrogen heat exchanger 105. Its function is to avoid too high hydrogen supply pressure.

[0034] The hydrogen heat exchanger 105 has its outlet connected to the inlet of the proportional valve 106, and a tee is arranged between them. Its function is to regulate the temperature of the hydrogen entering the small-power fuel cell stack 401.

[0035] The first proportional valve 106 has its outlet connected to the hydrogen inlet of the small-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 small-power fuel cell stack 401 under different working conditions.

[0036] Furthermore, the hydrogen supply system 100 further includes a second proportional valve 113, an ejector 114, and a second temperature and pressure integrated 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 temperature and pressure integrated sensor 116 is arranged in the connecting pipeline between the ejector 114 and the high-power fuel cell stack 403.

[0037] Specifically, the hydrogen storage bottle 101, the bottle mouth 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 form a hydrogen supply loop of the hydrogen supply system to the high-power fuel cell stack. Of course, the function of the ejector is not limited to this. The ejector is also used to re-eject the hydrogen separated by the first circulation system back to the high-power fuel cell stack.

[0038] The first circulation system 300 includes a fifth temperature and pressure integrated sensor 108, a first gas-water separator 109, a first nitrogen discharge valve 110, a first one-way valve 112, a hydrogen-saving valve 115, a sixth temperature and pressure integrated sensor 117, a second gas-water separator 118, and a second one-way valve 119; The outlet of the small-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 temperature and pressure integrated sensor 108 is arranged in the connecting pipeline between the small-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 temperature and pressure integrated sensor 117 is arranged 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 arranged 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; Among them, the hydrogen discharged from the outlet of the low-power fuel cell stack 401 and the hydrogen discharged from the outlet of the high-power fuel cell stack 403 are ejected to the inlet of the high-power fuel cell stack 403 through the ejector 114.

[0039] Optionally, the first circulation system 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 arranged in the connecting pipeline between the first gas-water separator 109 and the mixed discharge system 600. The second nitrogen discharge valve 120 and the second drain valve 121 are both connected to the second gas-water separator 118 and the mixed discharge system 600; Among them, the liquid water obtained by separating the gas-water mixture discharged from the low-power fuel cell stack 401 by the first gas-water separator 109 is discharged to the mixed discharge system 600 through the first drain valve 111; The nitrogen gas obtained by separating the gas-water mixture discharged from the high-power fuel cell stack 403 by the second gas-water separator 118 is discharged to the mixed discharge system 600 through the second nitrogen discharge valve 120; The liquid water obtained by separating the gas-water mixture discharged from the high-power fuel cell stack 403 by the second gas-water separator 118 is discharged to the mixed discharge system 600 through the second drain valve 121.

[0040] Specifically, for the first gas-water separator 109, its inlet is connected to the hydrogen outlet of the low-power fuel cell stack 401, and a fifth temperature and pressure integrated 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.

[0041] For the first nitrogen discharge valve 110, its inlet is connected to the outlet of the first gas-water separator 109 for discharging nitrogen, and its outlet is 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.

[0042] For the first drain valve 111, its inlet is connected to the outlet of the first gas-water separator 109 for discharging liquid water, and its outlet is connected to the mixed discharge pipe 501. Its function is to discharge the liquid water separated by the first gas-water separator 109.

[0043] The second proportional valve 113 has its inlet connected to the tee 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 working conditions.

[0044] The ejector 114 has a total of 3 inlets, which are respectively connected to the tee near the outlet of the check valve 112, the outlet of the check valve 119, and the outlet of the proportional valve 113; 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 the two. Its function is to eject the unreacted hydrogen discharged from the low-power fuel cell stack 401 and the high-power fuel cell stack 403, and increase the hydrogen utilization rate of the system.

[0045] The hydrogen-saving valve 115 has its inlet connected to the tee arranged between the first check valve 112 and the ejector 114, and its outlet connected to the tee 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 opened to maintain the temperature of the high-power fuel cell stack by using the exhaust heat of the low-power fuel cell stack; in addition, the interface connecting the upstream of the hydrogen-saving valve 115 to the ejector 114 has a very small diameter and cannot be used as a common pipeline to support the large-flow exhaust circulation. Only when the low-power and high-power fuel cell stacks are working simultaneously, the hydrogen-saving valve 115 is closed and the conduction is achieved by using the ejecting ability of the ejector 114.

[0046] 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 temperature and pressure integrated 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.

[0047] The second nitrogen discharge valve 120 has its inlet connected to the nitrogen discharge outlet of the second gas-water separator 118 and the inlet of the second check valve 119 through a tee. Its function is to maintain the hydrogen concentration in the hydrogen chamber of the high-power fuel cell stack 403.

[0048] The second drain valve 121 has its inlet connected to the liquid water discharge outlet of the second gas-water separator 118, and its outlet is connected to the mixed discharge pipe 501 through a tee. Its function is to discharge the liquid water separated by the first gas-water separator 109.

[0049] The air supply system 200 includes a third temperature and pressure integrated 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 small power fuel cell stack 401. The third temperature and pressure integrated sensor 206 is arranged in the connecting pipeline between the first humidifier 205 and the small power fuel cell stack 401. The first air filter 201 is used to introduce air in the atmosphere. The air supply system 200 further includes a fourth temperature and pressure integrated sensor 218, and a second air filter 212, a second air flowmeter 213, an air compressor 214, an intercooler 215, a second throttle valve 216, and a second humidifier 217 that are connected in sequence. The second humidifier 217 is connected to the inlet of the high-power fuel cell stack 403. The fourth temperature and pressure integrated sensor 218 is arranged in the connecting pipeline between the second humidifier 217 and the high-power fuel cell stack 403. The second air filter 212 is used to introduce air in the atmosphere.

[0050] The second circulation system 400 includes a seventh temperature and pressure integrated sensor 207, a first back pressure valve 208, a third gas-water separator 209, a humidifying valve 210, a third one-way valve 211, an eighth temperature and pressure integrated sensor 219, a second back pressure valve 220, and a bypass valve 221. The seventh temperature and pressure integrated sensor 207 is arranged between the outlet of the small power fuel cell stack 401 and the first humidifier 205. The eighth temperature and pressure integrated sensor 219 is arranged between the outlet of the high-power fuel cell stack and the second humidifier 217. The outlet of the small power fuel cell stack 401 is sequentially connected to the first humidifier 205, the third gas-water separator 209, the humidifying valve 210, the third one-way valve 211, and the inlet of the high-power fuel cell stack 403, so as to circularly transport the mixed gas discharged by the small power fuel cell stack 401 to the high-power fuel cell stack 403. The outlet of the small power fuel cell stack 401 is sequentially connected to the first humidifier 205, the first back pressure valve 208, and the mixed exhaust 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 mixed exhaust system 600. The bypass valve 221 is connected to the air cooler 215, the second throttle valve 216, and the mixed exhaust system.

[0051] Specifically, for the first air filter 201, its inlet is connected to the atmosphere. Its function is to filter impurities harmful to the small fuel cell stack in the air.

[0052] 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 therebetween for monitoring the air flow rate supplied to the small power fuel cell stack 401.

[0053] The inlet of the first throttle valve 204 is connected to the outlet of the blower 203.

[0054] 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 small power fuel cell stack 401, and a seventh temperature and pressure integrated sensor 207 is arranged therebetween; its dry side outlet is connected to the air inlet of the small power fuel cell stack 401, and a third temperature and pressure integrated sensor 206 is arranged therebetween; its wet side outlet is connected to the inlet of the first back pressure valve 208 through a tee pipe.

[0055] The inlet of the first back pressure valve 208 is connected to a tee pipe arranged near the wet side outlet of the first humidifier 205, and its outlet is connected to the mixing and discharging pipe 501 through a tee pipe. The first back pressure valve 208 is used to control the flow rate distribution of the mixed gas discharged by the small power fuel cell system.

[0056] The inlet of the second gas-water separator 209 is connected to a tee pipe arranged 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 small power fuel cell stack 401.

[0057] The inlet of the humidifying valve 210 is connected to the exhaust port of the second gas-water separator 209, and its outlet is 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 that the air entering the small power fuel cell stack 401 and the high-power fuel cell stack 403 is high-humidity air, and the water content of the high-humidity air is in the range of 60% to 95%.

[0058] The inlet of the second air filter 212 is connected to the atmosphere. Its function is to filter out impurities harmful to the fuel cell stack in the air.

[0059] The inlet of the air compressor 214 is connected to the outlet of the second air filter 212, and a second air flow meter 213 is arranged therebetween for monitoring the air flow rate supplied to the high-power fuel cell stack 403.

[0060] 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 with the blower 203, the temperature at the outlet of the air compressor 214 is higher, and it is necessary to reduce the temperature of the supplied air to meet the requirements of the fuel cell stack for the temperature of the supplied air.

[0061] The second throttle valve 216 has its inlet connected to the air outlet of the intercooler 215 through a tee pipe.

[0062] 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 temperature and pressure integrated 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 through a tee pipe, and a fourth temperature and pressure integrated 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.

[0063] The second back pressure valve 220 has its outlet connected to the mixing exhaust pipe 501 through a tee pipe. To avoid the surging of the humidifying valve 210, the second back pressure valve 220 discharges the tail exhaust gas and generated water of the high-power fuel cell stack 403 to the outside.

[0064] The bypass valve 221 has its inlet connected to the tee pipe between the air cooler 215 and the second throttle valve 216, and its outlet is connected to the mixing exhaust pipe 501 through a tee pipe.

[0065] The thermal management system 500 includes a water pump 301, a ninth temperature and pressure integrated sensor 302, a tenth temperature and pressure integrated 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 temperature and pressure integrated sensor 303, the thermostat 304, the heat dissipation device 306, the expansion tank 309, the ion filter 308, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a first circulation loop; The outlet of the high-power fuel cell stack 403, the tenth temperature and pressure integrated sensor 303, the PTC heater 305, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a second circulation loop; The outlet of the high-power fuel cell stack 403, the tenth temperature and pressure integrated sensor 303, the heat dissipation device 306, the particle filter 307, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are connected in sequence to form a third circulation loop.

[0066] Specifically, for the water pump 301, its outlet is connected to the coolant inlet of the high-power fuel cell system 403, and the ninth temperature and pressure integrated sensor 302 is arranged therebetween. Its function is to regulate the supply pressure and flow rate of the coolant.

[0067] 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 the tenth temperature and pressure integrated sensor 303 is arranged therebetween. Its function is to regulate the flow rate distribution of the coolant between the first circulation loop and the third circulation loop.

[0068] The PTC heater 305, its inlet is connected to the small circulation outlet of the thermostat 304. Its function is to heat the coolant.

[0069] The heat dissipation device 306 consists of a radiator and its fan, and its coolant inlet is connected to the outlet of the thermostat 304. Its function is to control the temperature of the coolant.

[0070] The particle filter 307, its inlet is connected to the coolant outlet of the radiator and its fan 306. Its function is to filter impurities in the coolant.

[0071] The ion filter 308, its inlet is connected to the water replenishing port of the expansion tank 309, and its outlet is arranged upstream of the water pump 301 via a three-way pipe. Its function is to reduce the conductivity of the coolant.

[0072] The expansion tank 309, its air inlet is connected to the exhaust port of the heat dissipation device 306.

[0073] The expansion tank 309 is integrated with a liquid level sensor, a water replenishing port, an air inlet, a liquid adding port and a pressure relief valve. The liquid level sensor can identify the liquid level height in the expansion tank 309 to avoid the poor operation of the thermal management system, too fast or too high temperature rise caused by too little coolant; the liquid level sensor can be arranged at the bottom or top of the expansion tank 309 according to the maintenance space. The water replenishing port should be arranged as close as possible to the middle of the bottom of the expansion tank 309 to avoid the inclination during vehicle driving affecting the water replenishing amount of the expansion tank 309. The air inlet of the expansion tank 309 is connected to the exhaust port of the heat dissipation device 306. In addition, multiple air inlets can be provided and connected to the exhaust ports near the coolant outlet of the heat dissipation 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 liquid adding port and the pressure relief valve can be integrated into one valve port according to the system requirements.

[0074] Further, the asymmetric multi-stack fuel cell system further 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 perform charge and discharge with 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 electric energy generated by the low-power fuel cell stack 401 and 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 to discharge to the power battery; The second DC-DC converter 404 is also used to deliver the electric energy generated by the high-power fuel cell stack 403 to the air compressor 214, the water pump 301 and the PTC heater 305.

[0075] For the low-power fuel cell stack 401, an air-cooled stack or a water-cooled stack can be considered. In the embodiment of the present application, an air-cooled stack is shown, which is integrated with an air inlet, an air outlet, a hydrogen inlet, a hydrogen outlet, etc. If a water-cooled stack is selected, an additional thermal management system is required or it shares the thermal management system of the high-power fuel cell stack 403. In addition, the high-voltage terminal of the low-power fuel cell stack 401 is connected to the high-voltage terminal of the first DC-DC converter 402.

[0076] As shown Figure 3 in the figure, the first DC-DC converter 402 has two high-voltage power output terminals. One is connected to the high-voltage power supply port of the blower 203 and is unidirectional power supply; the other is connected to the high-voltage power supply port of the second DC-DC converter 404 and is unidirectional power supply. Its function is to boost the output voltage of the low-power fuel cell stack 401, so as to meet the high-voltage power supply of the blower 203, the air compressor 214, the water pump 301 and the PTC heater 305.

[0077] 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, etc. In addition, an exhaust port can be considered to be arranged near the coolant outlet of the high-power fuel cell stack 403. In addition, the high-voltage terminal of the high-power fuel cell stack 403 is connected to the high-voltage terminal of the second DC-DC converter 404.

[0078] The second DC-DC converter 404 has four high-voltage power output terminals. One is connected to the high-voltage power supply port of the third DC-DC converter 406 in the power battery and is unidirectional power supply; the second is connected to the high-voltage power supply port of the air compressor 214 and is unidirectional power supply; the third is connected to the high-voltage power supply port of the water pump 301 and is unidirectional power supply; the fourth is connected to the high-voltage power supply port of the PTC heater 305 and is unidirectional power supply; its function is to boost the output voltage of the high-power fuel cell stack 403, so as to meet the high-voltage power supply of the air compressor 214, the water pump 301, the PTC heater 305 and the DC-DC converter 406.

[0079] The high-voltage terminal of the power battery 405 is connected to the high-voltage terminal of the DC-DC converter 406.

[0080] The high-voltage power input terminal of the third DC-DC converter 406 is connected to one high-voltage power output terminal of the DC-DC converter 404, and the power generated by the high-power fuel cell stack 403 can be used to charge the power battery 405; it can perform bidirectional power supply with the first DC-DC converter 402, so that the power battery 405 can be powered, and the power generated by the low-power fuel cell stack 401 can also be used to charge the power battery 405.

[0081] The muffler 502 is arranged downstream of the mixed exhaust pipe 501, and the mixed exhaust pipe 501 and the muffler 502 form a mixed exhaust system 600.

[0082] Existing technical solutions and their deficiencies: As the technical maturity of fuel cell systems gets higher and higher, the application scenarios of fuel cell systems are becoming increasingly widespread, but some problems have also emerged, restricting their popularization progress. Currently, in the application scenarios where fuel cell systems are installed, power batteries often need to be matched to assist the startup of fuel cell systems. However, in low-temperature environments, such as less than 0°C, the discharge characteristics of power batteries are poor, and even charging and discharging are not allowed, which greatly reduces the overall temperature adaptability of fuel cell systems in the installation scenarios. Therefore, effectively reducing the dependence on power batteries during the operation of fuel cell systems can improve the overall temperature adaptability of fuel cell systems in the installation scenarios.

[0083] For a fuel cell system with a rated power of about 100 kW, its idle power is usually between 3 and 5 kW. The system idle power usually has a proportional relationship with the system rated power, that is, the higher the system rated power, the higher the system idle power. If the system operates in the idle condition for a long time, it will cause the state of charge (SOC) of the power battery to be too high to be charged, and the idle power has nowhere to be consumed. In addition, in low-temperature environments, such as less than 0°C, the allowable charging power of the power battery is less than the idle power, or the power battery does not allow charging.

[0084] The technical problems solved by this application: As Figure 3 shown, the electric energy generated by the small-power fuel cell stack 401 is used to supply power to the blower, and the second DC-DC converter 404 is used to supply 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 deliver the electric energy generated by the high-power fuel cell stack 403 to the air compressor 214, the water pump 301, and the PTC heater 305, so as to solve the problem of difficult discharge of power batteries in low-temperature environments through the thermal management system 500, reduce the dependence of fuel cell systems on power batteries, and further improve the uncertainty problem of power battery selection.

[0085] Reduce the dependence of fuel cell systems without self-humidifying ability on humidifiers. In the embodiments of this application, the usage frequencies of the first humidifier 205 and the second humidifier 217 can be effectively reduced, and the power consumption can be reduced. Utilize the high-humidity gas at the cathode outlet of the small-power fuel cell system as a humidification source to humidify the high-power fuel cell system; Improve the hydrogen utilization rate of fuel cell systems during low-power operation. Utilize the unreacted hydrogen at the anode outlet of the small-power fuel cell system as a secondary hydrogen source to supply to the high-power fuel cell system, thereby improving the hydrogen utilization rate of the entire fuel cell system.

[0086] According to an embodiment of this application, a control method for an asymmetric multi-stack fuel cell system is also proposed. The method is applied to the above-mentioned asymmetric multi-stack fuel cell system, and the method includes: Obtain the first monitoring parameters of the first temperature and pressure integrated sensor and the third temperature and pressure integrated sensor; Judge whether to control the small-power fuel cell stack to start running according to the first monitoring parameters; After the small-power fuel cell stack starts running, obtain the first input current parameter of the small-power fuel cell stack; Judge whether to control the thermal management system to start running according to the input current parameter; After the thermal management system starts running, obtain the second monitoring parameters of the tenth temperature and pressure integrated sensor and the fourth temperature and pressure integrated sensor; Determine whether to control the high-power fuel cell stack to start running according to the second monitoring parameters; After the high-power fuel cell stack starts running, obtain the second input current parameter of the high-power fuel cell stack; Judge whether the asymmetric multi-stack fuel cell system starts successfully according to the second input current parameter.

[0087] Specifically, it can be referred to Figure 4 as shown in Figure 4 is a specific flowchart of the control method based on the asymmetric multi-stack fuel cell system, that is, the start control process of the asymmetric multi-stack fuel cell system, specifically as follows: Power on and wake up the controller, enter the self-check state, and complete the self-check process (not elaborated here). Judge whether a start-up instruction is received, that is, an instruction to start the fuel cell system. If the start-up instruction is not received, return to the self-check process; if the start-up instruction is received, control the actuators of the hydrogen supply system and the air supply system to work. Among them, the control of the actuator corresponding to the hydrogen supply system is specifically: Open the bottle 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.

[0088] The control of the actuator corresponding to the hydrogen supply system is specifically: Adjust the blower 203, open the first throttle valve 204, close the first back pressure valve 208, adjust the humidifying valve 210, close the air compressor 214, close the second throttle valve 216, adjust the second back pressure valve 220, and close the bypass valve 221.

[0089] At this time, it is judged whether the pressure P107 of the first temperature and pressure integrated sensor 107 (the pressure P107 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 temperature and pressure integrated sensor 206 (the pressure P206 can be obtained from the first monitoring parameter) is greater than or equal to P2 (here, the value can be 1.05 bar, or whether the actual positions of the blower 203 and the back pressure valve 208 reach the target positions). If the above two conditions are not met, wait and return to the previous step; if the above two conditions are met, the first DC-DC converter 402 can be started. It is judged whether the input current I402 of the first DC-DC converter 402 (that is, the first input current parameter of the small power fuel cell stack) is greater than or equal to I1 (here, the value can be 10 A, or other values less than the idle current), then control the actuator of the thermal management system to work and output the flag bit indicating the successful start of the small power fuel cell stack.

[0090] The control of the actuator corresponding to the thermal management system is specifically as follows: adjusting the water pump 301, adjusting the thermostat 304, adjusting the PTC heater 305, and turning off the radiator fan 306. It is judged 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 °C). If not, return to the previous step; if so, it is judged whether the requested power W is greater than or equal to the rated power of the small power fuel cell stack 401 - the input power of the blower 203 * 1.5. If not, return to control the actuator of the thermal management system to work; if so, control the actuators of the hydrogen supply system, the air supply system, and the thermal management system to work. Among them, the control of the hydrogen system actuator at this time includes opening the bottle valve 102, adjusting the first proportional valve 106, adjusting the first nitrogen discharge valve 110, adjusting the first drain valve 111, adjusting the second proportional valve 113, closing the hydrogen saving valve 115, adjusting the second nitrogen discharge valve 120, and adjusting the second drain valve 121.

[0091] The control of the actuator of the hydrogen supply system at this time specifically includes adjusting the blower 203, opening the first throttle valve 204, adjusting the first back pressure valve 208, adjusting the humidifying 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.

[0092] The control of the thermal management system actuator at this time includes adjusting the water pump 301, adjusting the thermostat 304, adjusting the PTC heater 305, and turning off the radiator fan 306. Determine whether the pressure P116 of the second temperature and pressure integrated sensor 116 is greater than or equal to P3 (here, it can take a value of 1.15 bar), and whether the pressure P228 of the fourth temperature and pressure integrated sensor 218 (the pressure P228 can be obtained from the second monitoring parameter) is greater than or equal to P4 (here, it can take a value of 1.05 bar, or identify whether the actual positions of the air compressor 214 and the second back pressure valve 220 reach the target positions). If the above two conditions are not met, wait and return to the previous step; if the above two conditions are met, the second DC-DC converter 404 can be started. Determine 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 (here, it can take a value of 10 A, or other values less than the idle current), then the startup of the asymmetric multi-stack fuel cell system is completed, and the flag bit indicating the successful startup of the low-power fuel cell stack is output.

[0093] Further, the control process of the idle control is as Figure 5 shown, and the idle control process is as follows: Wait and determine whether an idle command is received. If the idle command is not received, continue to wait; if the idle command is received, control the actuators corresponding to the hydrogen supply system, the actuators corresponding to the air supply system, and the actuators corresponding to the thermal management system to work.

[0094] Among them, the control of the actuator corresponding to the hydrogen supply system is specifically: Open the bottle 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.

[0095] The control of the actuator corresponding to the hydrogen supply system is specifically: Adjust the blower 203, open the first throttle valve 204, close the first back pressure valve 208, adjust the humidifying valve 210, close the air compressor 214, close the second throttle valve 216, adjust the second back pressure valve 220, and close the bypass valve 221.

[0096] The actuator control corresponding to the thermal management system includes regulating the water pump 301, regulating the thermostat 304, regulating the PTC heater 305, and turning off the radiator fan 306. At this time, the control of the actuators of the hydrogen supply system, the air supply system, and the thermal management system is completed, and the idle operation flag of the low-power fuel cell stack 401 / the shutdown flag of the high-power fuel cell stack 403 is output. It is judged whether a shutdown instruction is received. If no shutdown instruction is received, the actuators of the hydrogen supply system, the air supply system, and the thermal management system continue to work; if a shutdown instruction is received, the shutdown process is entered. It is judged whether the requested power W is greater than or equal to 0. If the judgment is not established, the actuators of the hydrogen supply system, the air supply system, and the thermal management system continue to work; if the judgment is established, the output currents of the low-power fuel cell stack 401 and the high-power fuel cell stack 403 are calculated, and the low-power fuel cell stack 401 and the high-power fuel cell stack 403 are loaded, and the fuel cell system enters the operating state, and it is continuously judged whether an idle instruction is received.

[0097] According to an embodiment of the present application, the asymmetric multi-stack fuel cell system of the present application can also be as Figure 6 shown Figure 6 Another implementation manner of the asymmetric multi-stack fuel cell system of the present application, different from Figure 2 is that: in Figure 6 , the first humidifier 205 and the second humidifier 217 are cancelled. Figure 6 For the low-power fuel cell stack 401 in , a fuel cell stack that does not require external humidification or can be self-humidified can be considered. The humidification of the high-power fuel cell stack 403 can be achieved only by adjusting the humidifying valve 210 and the third drain valve 222. Control the opening of the humidifying valve 210 to adjust the flow rate of the high-humidity cathode gas entering the high-power fuel cell stack 403 (the cathode gas discharged from the low-power fuel cell stack and separated by the gas-water separator 209); control the opening of the third drain valve 222 to adjust the water storage in the third gas-water separator 209. In addition, reducing two components can effectively reduce the system cost.

[0098] According to an embodiment of the present application, the asymmetric multi-stack fuel cell system of the present application can also be as Figure 7 shown Figure 7 Another implementation manner of the asymmetric multi-stack fuel cell system of the present application, different from Figure 2 is that: in Figure 7 , the first air filter 201 and the blower 203 are cancelled. Figure 7The air supply of the small and medium power fuel cell stack 401 is realized by controlling the 214 air compressor and the first throttle valve 204. The outside air is filtered by the second air filter 212, pressurized by the air compressor 214, cooled down by the intercooler 215, and the flow rate is adjusted by the first throttle valve 204, and then supplied to the small power fuel cell stack 401. In addition, for calculating the supply air flow rate of the large power fuel cell stack 403, the value of the second air flow meter 213 needs to be subtracted from the value of the first air flow meter 202. Therefore, reducing two components can lower the maintenance cost of the system.

[0099] In summary, in the present application, the hydrogen discharged from 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 the first circulation system, and the mixed gas with liquid water discharged from the small power fuel cell stack is circulated and transported to the large power fuel cell stack through the second circulation system, so that the unreacted mixed gas remaining in the reaction process of the small power fuel cell stack and the large power fuel cell stack can be recycled, improving the utilization rate of energy.

[0100] Furthermore, through the thermal management system, the asymmetric fuel cell stack of the present application can also be effectively started and operated in a special environment, thereby improving the overall temperature adaptability of the fuel cell system in the mounting scenario, without relying on the charge and discharge of the power battery to assist the start of the fuel cell stack.

[0101] Furthermore, it solves the problem of uncertainty in the selection of the power battery during the mounting process of the fuel cell system; solves the problem of difficult discharge of the power battery in a low-temperature environment, reducing the dependence of the fuel cell system on the power battery; reduces the dependence of the fuel cell system without self-humidifying ability on the humidifier, and uses the high-humidity gas at the cathode outlet of the small power fuel cell system as a humidifying source to humidify the large power fuel cell system; improves the hydrogen utilization rate of the fuel cell system during low-power operation, and uses the unreacted hydrogen at the anode outlet of the small power fuel cell system as a secondary hydrogen source to supply to the large power fuel cell system, thereby improving the hydrogen utilization rate of the asymmetric fuel cell system.

[0102] In the above description of this specification, the description with reference to terms such as "one embodiment", "another embodiment" or "certain embodiments" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0103] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the claims and their equivalents.

[0104] The above has specifically described the preferred embodiments of the present application, but the present application is not limited to the embodiments. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present application, and these equivalent deformations or substitutions are all included within the scope defined by the claims of the present 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 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; The hydrogen supply system 100 is respectively connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403, and the hydrogen supply system 100 is used to supply hydrogen meeting the first preset condition to the low-power fuel cell stack 401 and the high-power fuel cell stack 403; The air supply system 200 is respectively connected to the low-power fuel cell stack 401 and the high-power fuel cell stack 403, and the air supply system 200 is used to supply air meeting the second preset condition to the low-power fuel cell stack 401 and the high-power fuel cell stack 403; The first circulation system 300 is respectively connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the air supply system 200, and the mixed exhaust system 600, and the first circulation system 300 is used to circulate and transport the hydrogen discharged from 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 respectively connected to the low-power fuel cell stack 401, the high-power fuel cell stack 403, the hydrogen supply system 100, and the mixed exhaust system 600, and the second circulation system 400 is used to circulate and transport the mixed gas with liquid water discharged from 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 supply coolant meeting the third preset condition to the high-power fuel cell stack 403.

2. The asymmetric multi-stack fuel cell system according to claim 1, wherein The hydrogen supply system 100 includes a first temperature and pressure integrated sensor 107, and a hydrogen storage bottle 101, a bottle mouth 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 temperature and pressure integrated sensor 107 is arranged in the connection pipeline between the first proportional valve 106 and the low-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 temperature and pressure integrated 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 temperature and pressure integrated sensor 116 is arranged in the connection 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 temperature and pressure integrated sensor 108, a first gas-water separator 109, a first nitrogen discharge valve 110, a first one-way valve 112, a hydrogen control valve 115, a sixth temperature and pressure integrated sensor 117, a second gas-water separator 118, and a second one-way valve 119; The outlet of the small 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. The fifth temperature and pressure integrated sensor 108 is arranged in the connecting pipeline between the small 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. The sixth temperature and pressure integrated sensor 117 is arranged in the connecting pipeline between the high power fuel cell stack 403 and the second gas-water separator 118; The hydrogen control valve 115 is arranged in the connecting pipeline between the inlet of the high power fuel cell stack 403 and the first one-way valve 112. The hydrogen control valve 115 is used to adjust the hydrogen concentration at the inlet of the high power fuel cell stack 403; Wherein, the hydrogen discharged from the outlet of the small power fuel cell stack 401 and the hydrogen discharged from the outlet of the high power fuel cell stack 403 are ejected to the inlet of the high power fuel cell stack 403 through the ejector 114.

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

6. The asymmetric multi-stack fuel cell system according to claim 1, wherein The air supply system 200 includes a third temperature and pressure integrated 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 small power fuel cell stack 401. The third temperature and pressure integrated sensor 206 is arranged in the connecting pipeline between the first humidifier 205 and the small power fuel cell stack 401. The first air filter 201 is used to introduce air in the atmosphere. The air supply system 200 further includes a fourth temperature and pressure integrated 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 that are connected in sequence. The second humidifier 217 is connected to the inlet of the high-power fuel cell stack 403. The fourth temperature and pressure integrated sensor 218 is arranged in the connecting pipeline between the second humidifier 217 and the high-power fuel cell stack 403. The second air filter 212 is used to introduce air in 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 temperature and pressure integrated sensor 207, a first back pressure valve 208, a third gas-water separator 209, a humidifying valve 210, a third one-way valve 211, an eighth temperature and pressure integrated sensor 219, a second back pressure valve 220, and a bypass valve 221. The seventh temperature and pressure integrated sensor 207 is arranged between the outlet of the small power fuel cell stack 401 and the first humidifier 205. The eighth temperature and pressure integrated sensor 219 is arranged between the outlet of the high-power fuel cell stack and the second humidifier 217. The outlet of the small power fuel cell stack 401 is sequentially connected to the first humidifier 205, the third gas-water separator 209, the humidifying valve 210, the third one-way valve 211, and the inlet of the high-power fuel cell stack 403, so as to circulate and transport the mixed gas discharged by the small power fuel cell stack 401 to the high-power fuel cell stack 403. The outlet of the small power fuel cell stack 401 is sequentially connected to the first humidifier 205, the first back pressure valve 208, and the mixed exhaust 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 mixed exhaust system 600. The bypass valve 221 is connected to the air cooler 215, the second throttle valve 216, and the mixed exhaust system.

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 temperature and pressure integrated sensor 302, a tenth temperature and pressure integrated 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 temperature and pressure integrated sensor 303, the thermostat 304, the heat dissipation device 306, the expansion tank 309, the ion filter 308, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a first circulation loop. The outlet of the high-power fuel cell stack 403, the tenth temperature and pressure integrated sensor 303, the PTC heater 305, the water pump 301, the ninth temperature and pressure integrated sensor 302, and the inlet of the high-power fuel cell stack 403 are sequentially connected to form a second circulation loop; The outlet of the high-power fuel cell stack 403, the tenth temperature and pressure integrated sensor 303, the heat dissipation device 306, the particulate filter 307, the water pump 301, the ninth temperature and pressure integrated 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 further 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 a power battery to perform charge and discharge with 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, so as to supply power to the blower through the electric energy generated by the low-power fuel cell stack 401 and 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 to discharge to the power battery; The second DC-DC converter 404 is also used to deliver the electric 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 according to any one of claims 1-9, and the method includes: Obtain the first monitoring parameters of the first temperature and pressure integrated sensor and the third temperature and pressure integrated sensor; Judge whether to control the low-power fuel cell stack to start running according to the first monitoring parameters; After the low-power fuel cell stack starts running, obtain the first input current parameter of the low-power fuel cell stack; Judge whether to control the thermal management system to start running according to the input current parameter; After the thermal management system starts running, obtain the second monitoring parameters of the tenth temperature and pressure integrated sensor and the fourth temperature and pressure integrated sensor; Determine whether to control the high-power fuel cell stack to start running according to the second monitoring parameters; After the high-power fuel cell stack starts running, obtain the second input current parameter of the high-power fuel cell stack; Judge whether the asymmetric multi-stack fuel cell system starts successfully according to the second input current parameter.

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