Fuel cell system and vehicle
By subjecting the fuel cell system to a high-humidity state during idling, the voltage and output power of each cell are reduced, thus solving the problems of platinum corrosion and carbon corrosion in high-rated power systems, extending the stack life and meeting the power requirements of the vehicle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING CAVAN NEW ENERGY AUTOMOTIVE CO LTD
- Filing Date
- 2025-02-28
- Publication Date
- 2026-04-21
AI Technical Summary
High-rated-power fuel cell systems experience high average single-cell voltage under idling conditions, which exacerbates platinum and carbon corrosion and affects system lifespan. Existing idling solutions are ineffective in high-rated-power systems.
Under idling conditions, the water pump and water spray device work to keep the fuel cell stack in a high humidity state, reduce the average single cell voltage to 0.85V, reduce the ingress of liquid water, reduce the output power to meet the requirements of the whole vehicle, reduce corrosion, and extend the life of the fuel cell stack.
It effectively reduces corrosion and degradation of fuel cell systems, extends stack life, meets vehicle power requirements, and avoids the risk of overcharging power batteries.
Smart Images
Figure CN224153375U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a fuel cell system and a vehicle. Background Technology
[0002] To meet the power requirements of fuel cells in automobiles, the number of individual cells can be increased, or multiple stacks can be connected in series to meet the overall vehicle power requirements. High-power fuel cell systems have high idling power. When the fuel cell charges the battery, the higher net power increases the charging speed of the battery, easily leading to overcharging. High-power fuel cell systems are characterized by high voltage, low water production, and significant gas leakage during idling. Specifically, voltages exceeding 0.8V can cause platinum dissolution in the battery catalyst layer. When the voltage exceeds 1.2V, the carbon corrosion rate of the diffusion layer increases significantly, and the corrosion of the carbon support in the catalyst layer is exacerbated. All of these factors contribute to increased stack degradation and affect the lifespan of the fuel cell system.
[0003] Currently, the idling solution used in China for low-rated power fuel cell systems is a zero-power system solution: increasing the air compressor speed increases the power consumption of auxiliary systems, and by reducing oxygen content, the output power of the fuel cell stack is reduced, ultimately achieving zero system power. To extend the lifespan of the fuel cell and reduce its degradation, this solution can only be used for a short period. However, in high-rated power fuel cell systems, the average single-cell voltage will be higher under idling conditions, resulting in a greater impact on the fuel cell stack compared to low-rated power fuel cell systems. Summary of the Invention
[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the purpose of this invention is to propose a fuel cell system in which, under idling conditions, a water pump and a water spray device operate, creating a high-humidity environment in the air circulation loop, accompanied by liquid water entering the fuel cell stack. This flooding phenomenon inside the fuel cell stack reduces the average single-cell voltage at the same current density, thus reducing the output power of the fuel cell stack and consequently lowering the output power of the fuel cell system to the upper limit of the vehicle's power requirements. Simultaneously, the average single-cell voltage also decreases to 0.85V, mitigating platinum and carbon corrosion caused by high voltage, reducing stack degradation, extending stack life, and meeting vehicle requirements.
[0005] The second objective of this utility model is to provide a vehicle.
[0006] To achieve the above objectives, this utility model proposes a fuel cell system, comprising: a fuel cell stack; a humidity control device, the humidity control device including a water circuit component and an air circuit component; the water circuit component including a water pump and a water spraying device, the inlet of the water pump being connected to a water source, the outlet of the water pump being connected to the inlet of the water spraying device, and the spraying outlet of the water spraying device being connected to the fuel cell stack; the air circuit component including an air circulation loop, a bypass valve, and a humidification device, the air circulation loop including a three-way valve, the inlet of the three-way valve being connected to an air source through the air circulation loop, the first outlet of the three-way valve being connected to the air inlet of the bypass valve, the air outlet of the bypass valve being connected to the fuel cell stack, the second outlet of the three-way valve being connected to the air inlet of the humidification device, and the air outlet of the humidification device being connected to the fuel cell stack.
[0007] In addition, the fuel cell system described above according to this utility model may also have the following additional technical features:
[0008] Furthermore, the aforementioned fuel cell system also includes a hydrogen circulation loop; the hydrogen circulation loop includes a hydrogen circulation component, a hydrogen circulation pump, and a drain valve. The hydrogen source is connected to the hydrogen inlet of the fuel cell stack through the hydrogen circulation component, the water outlet of the fuel cell stack is connected to the water inlet of the drain valve, the outlet of the drain valve is connected to the inlet of the hydrogen circulation pump, the outlet of the hydrogen circulation pump is connected to the hydrogen circulation component, and the outlet of the drain valve is connected to a water source.
[0009] Furthermore, the air circulation loop also includes an air compressor, an intercooler, a second shut-off valve, and a water distributor; the air compressor's inlet is connected to an air source, the air compressor's outlet is connected to the intercooler's inlet, and the intercooler's outlet is connected to the inlet of a three-way valve; the third outlet of the three-way valve is connected to the water-air inlet of the water distributor through the second shut-off valve, the water distributor's outlet is connected to an air source, and the water distributor's outlet is connected to a water source.
[0010] Furthermore, the hydrogen recirculation assembly includes a first shut-off valve, a proportional valve, and an ejector assembly; the outlet of the hydrogen source is connected to the inlet of the ejector in sequence through the first shut-off valve and the proportional valve, and the outlet of the ejector is connected to the hydrogen inlet of the fuel cell stack.
[0011] Furthermore, the humidity control device also includes a back pressure valve; the inlet of the back pressure valve is connected to the humidification device, and the outlet of the back pressure valve is connected to the water and air inlet of the water distributor.
[0012] Furthermore, the aforementioned fuel cell system also includes a DC / DC module; the DC / DC module is used to record the voltage signal, current signal, and stack parameters of the fuel cell stack, and sends the voltage signal, current signal, and stack parameters of the fuel cell stack to the electrochemical impedance spectroscopy analysis module.
[0013] Furthermore, the aforementioned fuel cell system also includes an electrochemical impedance spectroscopy (EIS) analysis module; the EIS analysis module is used to determine the EIS of the fuel cell stack based on the voltage signal, current signal, and stack parameters, and to send the EIS to the operating condition control module.
[0014] Furthermore, the aforementioned fuel cell system also includes an operating condition control module; the operating condition control module is used to determine the real-time operating condition of the fuel cell stack based on the electrochemical impedance spectroscopy, and to control the humidity control device based on the real-time operating condition so that the real-time operating condition of the fuel cell stack reaches the target operating condition requirement.
[0015] The fuel cell system according to this utility model includes: a fuel cell stack; a humidity control device, which includes a water circuit component and an air circuit component; the water circuit component includes a water pump and a water spray device, the inlet of the water pump is connected to a water source, the outlet of the water pump is connected to the inlet of the water spray device, and the spray nozzle of the water spray device is connected to the fuel cell stack; the air circuit component includes an air circulation loop, a bypass valve, and a humidification device, the air circulation loop includes a three-way valve, the inlet of the three-way valve is connected to an air source through the air circulation loop, the first outlet of the three-way valve is connected to the air inlet of the bypass valve, the air outlet of the bypass valve is connected to the fuel cell stack, the second outlet of the three-way valve is connected to the air inlet of the humidification device, and the air outlet of the humidification device is connected to the fuel cell stack. Thus, under idling conditions, the water pump and the water spray device operate, the air circulation loop is in a high-humidity state, and liquid water enters the fuel cell stack. The fuel cell stack experiences water flooding, which reduces the average single-cell voltage at the same current density, reducing the output power of the fuel cell stack, thereby causing the output power of the fuel cell system to decrease to the upper limit of the vehicle's power requirements. At the same time, the average single-cell voltage will also be reduced to 0.85V, which will reduce platinum and carbon corrosion caused by high voltage, reduce fuel cell stack decay, extend fuel cell stack life, and meet the requirements of the whole vehicle.
[0016] To achieve the above objectives, a second aspect of this utility model provides a vehicle including the aforementioned fuel cell system.
[0017] According to the vehicle of this invention, through the aforementioned fuel cell system, the water pump and water spray device operate under idling conditions, creating a high-humidity environment in the air circulation loop, and liquid water enters the fuel cell stack. This flooding of the fuel cell stack reduces the average single-cell voltage at the same current density, thus lowering the fuel cell stack's output power and ultimately reducing the fuel cell system's output power to the upper limit of the vehicle's power requirements. Simultaneously, the average single-cell voltage also decreases to 0.85V, mitigating platinum and carbon corrosion caused by high voltage, reducing stack degradation, extending stack life, and meeting vehicle requirements.
[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0019] Figure 1 This is a block diagram of a fuel cell system according to some embodiments of the present invention;
[0020] Figure 2 This is a schematic diagram of the signal and control transmission architecture of a fuel cell stack according to some embodiments of the present invention.
[0021] Figure 3 This is a block diagram of a vehicle according to some embodiments of the present invention.
[0022] Explanation of reference numerals in the attached figures:
[0023] 100-Fuel cell system, 67-Fuel cell stack, 6-First fuel cell stack, 7-Second fuel cell stack, 20-Water pump, 21-Water spray device, 14-Bypass valve, 15-Humidification device, 13-Three-way valve, 9-Hydrogen circulation pump, 8-Drain valve, 2-First shut-off valve, 3-Proportional valve, 45-Ejector assembly, 4-First ejector, 5-Second ejector, 11-Air compressor, 12-Intercooler, 17-Second shut-off valve, 18-Water distributor, 16-Back pressure valve, 19-Water source, 10-Air source, 1-Hydrogen source, 32-DC / DC module, 33-Electrochemical impedance spectroscopy analysis module, and 34-Operating condition control module. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0025] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar words used in the embodiments of this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0026] As described in the background section, to meet the power requirements of fuel cells in automobiles, the number of individual cells can be increased, or multiple stacks can be connected in series to meet the overall vehicle power requirements. High-power fuel cell systems have high idle power. When the fuel cell charges the battery, the higher net power increases the charging speed of the battery, easily leading to overcharging. The idling condition of high-power fuel cell systems is characterized by high voltage, low water production, and large gas permeation. Specifically, a voltage exceeding 0.8V can cause platinum dissolution in the battery catalyst layer. When the voltage exceeds 1.2V, the carbon corrosion decay rate of the diffusion layer increases significantly, and the corrosion of the carbon support in the catalyst layer is aggravated. All of these factors exacerbate stack degradation and affect the lifespan of the fuel cell system. Therefore, the average voltage per cell is generally set to not exceed 0.85V. Since the fuel cell charges the battery at idle, the vehicle requires an upper limit on the idle power demand of the fuel cell to prevent excessively fast charging, which could lead to the battery being fully charged in a short time, resulting in overcharging and potentially causing spontaneous combustion or explosion.
[0027] The higher the rated power of a fuel cell system, the greater its system power at idle. Therefore, for high-rated power fuel cell systems (greater than 300kW), different manufacturers have different standards for idle conditions. Here are two common idle condition settings: 1. Idle condition is set at 0kW system power, where the average single-cell voltage is close to 1V. 2. Idle condition current density is set at 0.1A / cm². 2 Nearby. III. Idle operating condition is set when the average single-chip voltage is less than 0.85V and the system power is less than the set power.
[0028] Regarding the first scenario, the resulting high voltage accelerates platinum dissolution and carbon corrosion, exacerbating the degradation of the fuel cell stack and hindering long-term use. Regarding the second scenario, the idle speed condition is set at a current density of 0.1 A / cm². 2 In the vicinity, this is reasonable for low-rated power fuel cell systems, where the average single-cell voltage is less than 0.85V, which can reduce fuel cell degradation; while in high-rated power fuel cell systems, the current density is 0.1A / cm². 2 Near the catalytic layer, the average voltage of a single cell exceeds 0.85V, accelerating the dissolution of platinum and affecting the catalytic decomposition of hydrogen, thus accelerating fuel cell degradation. Regarding the third scenario mentioned above, it is more applicable to low-rated power fuel cells. However, in high-rated power fuel cell systems, if the average voltage of a single cell is below 0.85V, the fuel cell system power will be too high, exceeding the upper limit of the vehicle's idle power requirement, potentially leading to overcharging of the battery. In summary, the idle power of a high-rated power fuel cell system is constrained by the average voltage of a single cell and the vehicle's idle power requirement.
[0029] In developing this utility model, the applicant discovered that the current idling scheme used in China for low-rated-power fuel cell systems is a zero-power scheme: increasing the air compressor speed increases the power consumption of the auxiliary system, and by reducing the oxygen content, the output power of the fuel cell stack is reduced, ultimately achieving zero system power. To extend the lifespan of the fuel cell and reduce its degradation, this scheme can only be used for a short period. However, in high-rated-power fuel cell systems, the average single-cell voltage will be higher under idling conditions, resulting in a greater impact on the fuel cell stack compared to low-rated-power fuel cell systems. Therefore, the above scheme is not suitable for high-rated-power fuel cells.
[0030] Therefore, this invention enables the water pump and spray device to operate under idling conditions, creating a high-humidity environment in the air circulation loop, and introducing liquid water into the fuel cell stack. This flooding of the fuel cell stack reduces the average cell voltage at the same current density, thus lowering the fuel cell stack's output power and ultimately reducing the fuel cell system's output power to the upper limit required by the vehicle's power requirements. Simultaneously, the average cell voltage also decreases to 0.85V, mitigating platinum and carbon corrosion caused by high voltage, reducing stack degradation, extending stack life, and meeting vehicle requirements.
[0031] The fuel cell system and vehicle proposed in the embodiments of this utility model are described below with reference to the accompanying drawings.
[0032] refer to Figure 1 This is a block diagram of a fuel cell system according to some embodiments of the present invention.
[0033] The fuel cell system 100 of this utility model includes a fuel cell stack 67 and a humidity control device.
[0034] The fuel cell stack 67 includes a first fuel cell stack 6 and a second fuel cell stack 7. The humidity control device includes a water circuit assembly and a gas circuit assembly.
[0035] The water system includes a water pump 20 and a water spraying device 21. The water spraying device 21 can be an atomizing sprayer used to spray water mist onto the fuel cell stack 67 to humidify it. The inlet of the water pump 20 is connected to a water source 19, which can be used to supply water, such as a water tank or a small river. The outlet of the water pump 20 is connected to the inlet of the water spraying device 21, and the spray nozzles of the water spraying device 21 are connected to the first fuel cell stack 6 and the second fuel cell stack 7, respectively.
[0036] The air circuit assembly includes an air circulation loop, a bypass valve 14, and a humidification device 15.
[0037] The air circulation loop includes a three-way valve 13. The inlet of the three-way valve 13 is connected to an air source 10 through the air circulation loop. The air source 10 can be used to provide air, for example, the atmospheric environment. The first outlet of the three-way valve 13 is connected to the air inlet of a bypass valve 14. The air outlet of the bypass valve 14 is connected to the first fuel cell stack 6 and the second fuel cell stack 7, respectively. The second outlet of the three-way valve 13 is connected to the air inlet of a humidification device 15. The humidification device 15 is used to humidify the fuel cell stack 67. For example, the humidification device 15 can be a humidifier. The air outlet of the humidification device 15 is connected to the fuel cell stack 67.
[0038] The fuel cell system 100 also includes a hydrogen recirculation loop.
[0039] The hydrogen circulation loop includes a hydrogen circulation assembly, a hydrogen circulation pump 9, and a drain valve 8. The hydrogen circulation assembly includes a first shut-off valve 2, a proportional valve 3, and an ejector assembly 45, which includes a first ejector 4 and a second ejector 5. A hydrogen source 1 is connected to the hydrogen inlet of the fuel cell stack 67 via the hydrogen circulation assembly. The hydrogen source 1 provides hydrogen, for example, from a gas cylinder. The water outlet of the fuel cell stack 67 is connected to the water inlet of the drain valve 8. The outlet of the drain valve 8 is connected to the inlet of the hydrogen circulation pump 9. The outlet of the hydrogen circulation pump 9 is connected to the first ejector 4 and the second ejector 5, respectively. The outlet of the drain valve 8 is connected to a water source 19. The outlet of the hydrogen source 1 is connected sequentially to the inlets of the first ejector 4 and the second ejector 5 via the first shut-off valve 2 and the proportional valve 3, respectively. The outlets of the first ejector 4 and the second ejector 5 are connected to the hydrogen inlets of the first fuel cell stack 6 and the second fuel cell stack 7, respectively.
[0040] The air circulation loop also includes an air compressor 11, an intercooler 12, a second shut-off valve 17, and a water distributor 18.
[0041] The air inlet of air compressor 11 is connected to air source 10, the air outlet of air compressor 11 is connected to air inlet of intercooler 12, and the air outlet of intercooler 12 is connected to inlet of three-way valve 13. The third outlet of three-way valve 13 is connected to water-air inlet of water distributor 18 through second shut-off valve 17, the air outlet of water distributor 18 is connected to air source 10, and the water outlet of water distributor 18 is connected to water source 19.
[0042] The humidity control device also includes a back pressure valve 16, the inlet of which is connected to the humidification device 15, and the outlet of which is connected to the water and air inlet of the water distributor 18.
[0043] The fuel cell system 100 also includes a DC / DC module 32, which is used to record the voltage signal, current signal and stack parameters of the fuel cell stack 67. The stack parameters can include rated power, peak power, current density, voltage efficiency, operating life, maximum operating temperature, operating ambient temperature and thermal stability, etc. The DC / DC module 32 sends the voltage signal, current signal and stack parameters of the fuel cell stack 67 to the electrochemical impedance spectroscopy analysis module 33.
[0044] The fuel cell system 100 also includes an electrochemical impedance spectroscopy analysis module 33, which is used to determine the electrochemical impedance spectrum of the fuel cell stack 67 based on the voltage signal, current signal and stack parameters of the fuel cell stack 67 sent by the DC / DC module 32, and send the electrochemical impedance spectrum to the operating condition control module 34.
[0045] The fuel cell system 100 also includes an operating condition control module 34, which is used to determine the real-time operating condition of the fuel cell stack 67 based on the electrochemical impedance spectroscopy sent by the electrochemical impedance spectroscopy analysis module 33, and to control the humidity control device based on the real-time operating condition so that the real-time operating condition of the fuel cell stack 67 reaches the target operating condition requirement.
[0046] In some embodiments, reference Figure 2 This is a schematic diagram of the signal and control transmission architecture of a fuel cell stack according to some embodiments of the present invention. The voltage and current signals, as well as stack parameters, output from the first fuel cell stack 6 and the second fuel cell stack 7 are transmitted to the DC / DC module 32. The DC / DC module 32 transmits the voltage and current signals to the operating condition control module 34. The DC / DC module 32 also transmits the stack parameters to the electrochemical impedance spectroscopy analysis module 33. The electrochemical impedance spectroscopy analysis module 33 processes the stack parameters. The operating condition control module 34 determines the humidity status of the first fuel cell stack 6 and the second fuel cell stack 7 (mainly determining whether the first fuel cell stack 6 and the second fuel cell stack 7 have experienced flooding or membrane drying). When the vehicle demand is transmitted to the operating condition control module 34, the operating condition control module 34 processes the signal and transmits it to the DC / DC module 32. Finally, the DC / DC module 32 controls the first fuel cell stack 6 and the second fuel cell stack 7 to output power.
[0047] The system comprises the following components: a first fuel cell stack 6, which converts the chemical energy of hydrogen and oxygen into electrical energy; a second fuel cell stack 7, which converts the chemical energy of hydrogen and oxygen into electrical energy; a water pump 20, which extracts stored water from a water source 19; a water spray device 21, which sprays water mist onto the first and second fuel cell stacks 6 and 7 to humidify them; a bypass valve 14, which regulates the flow rate of coolant to ensure uniform temperature between the first and second fuel cell stacks 6 and 7; a humidification device 15, which humidifies the first and second fuel cell stacks 6 and 7; a three-way valve 13, which controls the flow direction of coolant; a hydrogen circulation pump 9, which circulates unreacted hydrogen from the outlets of the first and second fuel cell stacks 6 and 7 to the inlet to improve hydrogen utilization and simultaneously circulates water vapor to the inlet for humidification; and a drain valve 8, which drains water from the first and second fuel cell stacks 6 and 7. Water is discharged; the first shut-off valve 2 is used to control the hydrogen supply; the proportional valve 3 is used to adjust the hydrogen pressure entering the first fuel cell stack 6 and the second fuel cell stack 7 to adapt to different operating conditions; the first ejector 4 is used to draw in and discharge unreacted hydrogen and water vapor; the second ejector 5 is used to draw in and discharge unreacted hydrogen and water vapor; the air compressor 11 is used to provide high-pressure air to the first fuel cell stack 6 and the second fuel cell stack 7 to ensure sufficient oxygen supply; the intercooler 12 is used to reduce the high temperature air at the outlet of the air compressor 11; the second shut-off valve 17 is used to control the air supply; the water separator 18 is used to separate moisture from the air to prevent moisture from entering the first fuel cell stack 6 and the second fuel cell stack 7; the back pressure valve 16 is used to maintain the pressure stability of the stored water or gas in the fuel cell system 100 to prevent pressure fluctuations; the water source 19 is used to provide stored water; the air source 10 is used to provide air; and the hydrogen source 1 is used to provide hydrogen.
[0048] Therefore, the fuel cell system 100 of this utility model includes a first fuel cell stack 6, a second fuel cell stack 7, a water pump 20, a water spray device 21, a bypass valve 14, a humidification device 15, a three-way valve 13, a hydrogen circulation pump 9, a drain valve 8, a first shut-off valve 2, a proportional valve 3, a first ejector 4, a second ejector 5, an air compressor 11, an intercooler 12, a second shut-off valve 17, a water distributor 18, a back pressure valve 16, a water source 19, an air source 10, a hydrogen source 1, a DC / DC module 32, an electrochemical impedance spectroscopy analysis module 33, and an operating condition control module 34.
[0049] Hydrogen gas enters the first fuel cell stack 6 and the second fuel cell stack 7 via hydrogen source 1, first shut-off valve 2, proportional valve 3, first ejector 4, and second ejector 5. At this point, the mixture exiting the first fuel cell stack 6 and the second fuel cell stack 7 contains hydrogen, nitrogen, water vapor, and liquid water. The liquid water in the exiting mixture is drained into water source 19 via drain valve 8, and the remaining mixture re-enters the first ejector 4 and the second ejector 5 via hydrogen circulation pump 9.
[0050] Air enters through air source 10, passes through air compressor 11, and then enters intercooler 12 before converging into three-way valve 13. One path of three-way valve 13 leads to the first fuel cell stack 6 and the second fuel cell stack 7 via three-way valve 13 or humidification device 15; the other path of three-way valve 13 leads to the second shut-off valve 17 and water distributor 18, with the gas portion directly discharged into air source 10. The gas discharged from the first fuel cell stack 6 and the second fuel cell stack 7 passes through humidification device 15, back pressure valve 16, and water distributor 18 before finally being discharged back to air source 10, with the liquid water portion entering water source 19.
[0051] The stored water in water source 19 can be pumped into the first fuel cell stack 6 and the second fuel cell stack 7 along with the air through water pump 20 and water spray device 21 as needed under operating conditions. This can meet the vehicle power requirements under idling conditions, greatly reduce fuel cell degradation, and extend the life of the fuel cell system 100.
[0052] In summary, the fuel cell system according to this embodiment of the present invention includes: a fuel cell stack; a humidity control device, which includes a water circuit component and an air circuit component; the water circuit component includes a water pump and a water spray device, the inlet of the water pump is connected to a water source, the outlet of the water pump is connected to the inlet of the water spray device, and the spray nozzle of the water spray device is connected to the fuel cell stack; the air circuit component includes an air circulation loop, a bypass valve, and a humidification device, the air circulation loop includes a three-way valve, the inlet of the three-way valve is connected to an air source through the air circulation loop, the first outlet of the three-way valve is connected to the air inlet of the bypass valve, the air outlet of the bypass valve is connected to the fuel cell stack, the second outlet of the three-way valve is connected to the air inlet of the humidification device, and the air outlet of the humidification device is connected to the fuel cell stack. Therefore, in this system, under idling conditions, the water pump and the water spray device operate, the air circulation loop is in a high-humidity state, and liquid water enters the fuel cell stack. The internal water-flooding phenomenon of the fuel cell stack reduces the average cell voltage at the same current density, thereby lowering the output power of the fuel cell stack and ultimately reducing the output power of the fuel cell system to the upper limit of the vehicle's power requirements. Simultaneously, the average cell voltage also decreases to 0.85V, mitigating platinum and carbon corrosion caused by high voltage, reducing stack degradation, extending stack life, and meeting vehicle requirements.
[0053] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this utility model also provides a vehicle, such as... Figure 3 As shown, vehicle 700 includes the aforementioned fuel cell system 100.
[0054] According to the vehicle of this utility model embodiment, the above-described fuel cell system reduces the idling power of the fuel cell system to meet the vehicle's idling power constraints and voltage requirements. Under idling conditions, the system switches from multi-stack operation to single-stack operation. Based on this, the current density can be increased to reduce the average single-cell voltage to meet the requirement of below 0.85V. Single-stack operation also ensures that the output power is lower than the vehicle's required idling power constraints. By injecting water to rest the stack, the generation of the hydrogen-air interface is avoided, reducing the damage to the stack caused by the resting process, reducing hydrogen consumption, and improving the stack's service life.
[0055] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this utility model should have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar words used in the embodiments of this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0056] While the spirit and principles of this invention have been described with reference to several specific embodiments, it should be understood that this invention is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for ease of description. This invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be interpreted in the broadest sense, thereby encompassing all such modifications and equivalent structures and functions.
Claims
1. A fuel cell system characterized by comprising: include: Fuel cell stack (67); A humidity control device, the humidity control device comprising a water circuit component and an air circuit component; The water circuit assembly includes a water pump (20) and a water spray device (21). The inlet of the water pump (20) is connected to a water source (19), the outlet of the water pump (20) is connected to the inlet of the water spray device (21), and the spray nozzle of the water spray device (21) is connected to the fuel cell stack (67). The air circuit assembly includes an air circulation loop, a bypass valve (14), and a humidification device (15). The air circulation loop includes a three-way valve (13). The inlet of the three-way valve (13) is connected to an air source (10) through the air circulation loop. The first outlet of the three-way valve (13) is connected to the air inlet of the bypass valve (14). The air outlet of the bypass valve (14) is connected to the fuel cell stack (67). The second outlet of the three-way valve (13) is connected to the air inlet of the humidification device (15). The air outlet of the humidification device (15) is connected to the fuel cell stack (67).
2. The fuel cell system of claim 1, wherein It also includes a hydrogen recirculation loop; The hydrogen circulation loop includes a hydrogen circulation assembly, a hydrogen circulation pump (9), and a drain valve (8). The hydrogen source (1) is connected to the hydrogen inlet of the fuel cell stack (67) through the hydrogen circulation assembly. The water outlet of the fuel cell stack (67) is connected to the water inlet of the drain valve (8). The outlet of the drain valve (8) is connected to the inlet of the hydrogen circulation pump (9). The outlet of the hydrogen circulation pump (9) is connected to the hydrogen circulation assembly. The outlet of the drain valve (8) is connected to the water source (19).
3. The fuel cell system of claim 2, wherein The air circulation loop also includes an air compressor (11), an intercooler (12), a second shut-off valve (17), and a water distributor (18). The air inlet of the air compressor (11) is connected to the air source (10), the air outlet of the air compressor (11) is connected to the air inlet of the intercooler (12), and the air outlet of the intercooler (12) is connected to the inlet of the three-way valve (13). The third outlet of the three-way valve (13) is connected to the water and air inlet of the water distributor (18) through the second shut-off valve (17). The air outlet of the water distributor (18) is connected to the air source (10), and the water outlet of the water distributor (18) is connected to the water source (19).
4. The fuel cell system of claim 3, wherein The hydrogen recirculation assembly includes a first shut-off valve (2), a proportional valve (3), and an ejector assembly (45). The outlet of the hydrogen source (1) is connected to the inlet of the ejector in sequence through the first shut-off valve (2) and the proportional valve (3), and the outlet of the ejector is connected to the hydrogen inlet of the fuel cell stack (67).
5. The fuel cell system of claim 4, wherein The humidity control device also includes a back pressure valve (16). The inlet of the back pressure valve (16) is connected to the humidification device (15), and the outlet of the back pressure valve (16) is connected to the water and air inlet of the water distributor (18).
6. The fuel cell system of claim 4, wherein It also includes a DC / DC module (32); The DC / DC module (32) is used to record the voltage signal, current signal and stack parameters of the fuel cell stack (67), and send the voltage signal, current signal and stack parameters of the fuel cell stack (67) to the electrochemical impedance spectroscopy analysis module (33).
7. The fuel cell system of claim 6, wherein It also includes an electrochemical impedance spectroscopy analysis module (33); The electrochemical impedance spectroscopy analysis module (33) is used to determine the electrochemical impedance spectrum of the fuel cell stack (67) based on the voltage signal, current signal and stack parameters, and send the electrochemical impedance spectrum to the operating condition control module (34).
8. The fuel cell system of claim 7, wherein It also includes a condition control module (34); The operating condition control module (34) is used to determine the real-time operating condition of the fuel cell stack (67) based on the electrochemical impedance spectroscopy, and to control the humidity control device based on the real-time operating condition so that the real-time operating condition of the fuel cell stack (67) meets the target operating condition requirements.
9. A vehicle characterized by comprising: Including the fuel cell system as described in any one of claims 1-8.