Fuel cell system
By adding bypass pipelines and pressure adjustment devices to the cathode exhaust pipeline of the fuel cell system, the problem of difficulty in regulating exhaust pressure in high altitude and water wading scenarios is solved, and the normal operation and performance improvement of the system in different environments is achieved. .
Patent Information
- Application Number
- CN202420266100.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-02
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-02-02
AI Technical Summary
Existing fuel cell systems with turbines have difficulty in regulating exhaust pressures in high altitudes and in water wading scenarios, resulting in a decline in system performance or an increased risk.
Add a bypass line and a pressure adjustment device to the cathode exhaust line of the fuel cell system, and adjust the exhaust pressure through the bypass of the turbocharger and water separator to ensure the normal operation of the system under different environments.
By flexibly adjusting the exhaust pressure on the cathode exhaust pipeline, it can adapt to special occasions such as high altitude and wading, ensuring the normal driving of the vehicle, and reducing the power consumption and risks of the system.
Smart Images
Figure CN222483425U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a fuel cell system for a vehicle, and in particular to a fuel cell system capable of regulating the exhaust pressure of the vehicle. Background Art
[0002] At present, fuel cell power modules are gradually being used in commercial vehicles and engineering vehicles, and their large-scale use has played a positive role in carbon neutrality and environmental protection. In order to increase the available net power of the power module and improve the efficiency of the system, most existing vehicles use air compressors with turbines to recover the mechanical energy of exhaust gas from the fuel cell stack to reduce power consumption and improve system efficiency.
[0003] However, fuel cell power modules with turbines have certain limitations when used in high-altitude areas (low-pressure areas) and wading scenarios (high exhaust gas back pressure) that are higher than the vehicle setting value. For example, the intake pressure becomes lower in the high-altitude areas, but due to the water-gas separator in the exhaust system and the electric air compressor turbine structure, the working pressure of the stack cannot be reduced accordingly. This situation will cause the required air compressor pressure ratio to increase. If the capacity of the air compressor is exceeded, the intake of the stack cannot be guaranteed, which will affect the performance of the fuel cell power module in the high-altitude areas.
[0004] When a fuel cell vehicle is wading (for example, the tail pipe of the vehicle is at a depth of about 0.5m), the required exhaust pressure is forced to increase due to water entering the vehicle exhaust pipe. In this case, in order to exhaust smoothly, the gas path control of the fuel cell system will increase the exhaust pressure of the system through the intake bypass. This will increase the power consumption of the electric air compressor. If the wading depth increases, the system cannot meet the exhaust pressure requirements, and there is a risk of water flowing into the vehicle or the fuel cell power module.
[0005] Therefore, there is a need for a fuel cell system that can still work normally in such a special driving environment. Utility Model Content
[0006] The present application aims to provide a fuel cell system that can overcome the above-mentioned defects and can adjust the exhaust pressure of the cathode of the fuel cell system.
[0007] To achieve the above-mentioned objectives, the present application provides a fuel cell system, which includes: a fuel cell stack having an anode and a cathode, the cathode having a cathode gas inlet and a cathode gas outlet; a cathode gas supply line for supplying cathode gas to the cathode gas inlet and a cathode exhaust line for discharging cathode exhaust gas from the cathode gas outlet; a turbocharger located between the cathode gas supply line and the cathode exhaust line, the turbocharger including a turbine connected to the cathode exhaust line and an air compressor connected to the cathode gas supply line; and a water separator located on the cathode exhaust line between the turbine and the cathode gas outlet, wherein the fuel cell system also includes a bypass line connected between the upstream of the water separator and the downstream of the turbine and a pressure regulating device for controlling the connection and disconnection of the bypass line and regulating the fluid flow and pressure in the bypass line.
[0008] Wherein, the pressure regulating device is a pressure regulating valve located on the bypass line.
[0009] Wherein, the pressure regulating valve is an electromagnetic pressure regulating valve, or a regulating valve controlled by a motor or mechanically.
[0010] Optionally, the fuel cell system further includes a bypass valve disposed between the cathode gas supply line and the cathode exhaust line.
[0011] Optionally, the pressure regulating device is a four-way valve connecting the bypass line, the cathode gas supply line and the cathode exhaust line.
[0012] Optionally, a pressure sensor for detecting gas pressure is also provided in the bypass line.
[0013] Optionally, the pressure regulating device is closed when the vehicle is driving normally, and the cathode exhaust gas enters the vehicle tail pipe through the water separator and the turbine.
[0014] Alternatively, the pressure regulating device is opened when the vehicle is traveling at a higher altitude than the vehicle setting value or when the vehicle is wading, the cathode exhaust gas flows directly to the vehicle tail pipe through the bypass line, and the exhaust pressure leading to the vehicle tail pipe is regulated by the pressure regulating device.
[0015] Optionally, the pressure regulating device is associated with a fuel cell control unit FCCU of the vehicle and is controlled to operate by the fuel cell control unit FCCU.
[0016] Optionally, the fuel cell system is provided with a pressure sensor for detecting the vehicle environment pressure, and the pressure regulating device is opened when the value detected by the pressure sensor is lower than a threshold value.
[0017] Optionally, the fuel cell system is further provided with an electronic control device for controlling the opening of the pressure regulating valve according to the ambient pressure value. Or the fuel cell system is provided with an electronic control device for controlling the flow direction and opening of the four-way valve according to the ambient pressure value.
[0018] According to the present application, by adding a bypass line to the cathode exhaust line of the fuel cell system, the exhaust pressure on the entire cathode exhaust line can be flexibly adjusted, so that the vehicle can be used in special occasions such as high altitude areas and wading that are higher than the vehicle setting value, thereby ensuring the normal driving of the vehicle in special occasions. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and other aspects of the present application will be more clearly understood in conjunction with the accompanying drawings. It should be noted that the drawings are only schematic and are not drawn to scale. In the drawings:
[0020] Figure 1 A fuel cell system according to a first embodiment of the present application is schematically shown, and only a portion of a cathode loop of the fuel cell system is shown;
[0021] Figure 2 A fuel cell system according to a second embodiment of the present application is schematically shown;
[0022] Figure 3 A block diagram of the cathode exhaust gas adjustment process of the fuel cell system according to the present application in different driving scenarios is shown. These driving scenarios may include, for example, driving in a high altitude area higher than the vehicle setting value and wading. DETAILED DESCRIPTION
[0023] The preferred embodiments of the present application are described in detail below in conjunction with examples. It should be understood by those skilled in the art that the following embodiments are not intended to limit the present application in any way, and the features in the embodiments may be combined with each other. In different drawings, the same components are represented by the same reference numerals, and for the sake of brevity, some components are omitted, but this does not mean that other components are excluded. It should be understood that the size, proportional relationship and number of components of the various components in the drawings are not intended to limit the present application.
[0024] Figure 1 A fuel cell system 10 according to a first embodiment of the present application is schematically shown. The fuel cell system 10 can provide power to a vehicle to drive the vehicle. Figure 1As shown, the fuel cell system 10 may include a stack 1. The stack 1 includes an anode 2 and a cathode 3. During the operation of the fuel cell system 10, hydrogen and air are supplied to the anode 2 and cathode 3 of the stack 1, respectively. Hydrogen is supplied to the anode from a hydrogen source, and the hydrogen molecules entering the anode 2 are adsorbed by the catalyst and ionized into hydrogen ions and electrons. The hydrogen ions are transferred to the cathode 3 via the proton exchange membrane in the stack 1, and the electrons flow to the cathode 3 through an external circuit to form an electric current. The remaining hydrogen is discharged into the hydrogen loop through the anode outlet valve, but in Figure 1 The hydrogen circuit of the anode is not shown, but only the air circuit of the cathode 3 is shown.
[0025] Air enters the cathode 3 from the cathode gas inlet 5, and oxygen in the air combines with hydrogen ions and electrons to form water molecules at the cathode 3, and is discharged from the cathode gas outlet 6 together with other gases in the air. The gas discharged from the cathode gas outlet 6 may be referred to as "cathode exhaust gas". The fuel cell system 10 also includes a cathode gas supply line 8 configured to be connected between an oxidizing gas source, such as an air source 7, and the cathode gas inlet 5 and used to supply air to the cathode gas inlet 5, and a cathode exhaust line 9 configured to connect the cathode gas outlet 6 with the outside of the fuel cell system 10 and used to discharge the cathode exhaust gas from the fuel cell system 10.
[0026] The fuel cell system 10 of the present application also has a turbocharger 11, which includes an air compressor 111 and a turbine 112. The turbine 112 is connected to the cathode exhaust line 9 to be driven by the cathode exhaust gas in the cathode exhaust line 9. The air compressor 111 is connected to the cathode supply line 8 and is configured to be at least partially driven by the turbine 112 to supply air to the cathode gas inlet 5. That is, the air compressor 111 is operatively connected to the turbine 112 to be at least partially driven by the turbine 112. The cathode exhaust gas in the cathode exhaust line 9 impacts the turbine blades of the turbine 112 to drive the turbine blades to rotate, and this rotation drives the impeller of the air compressor 111 to rotate through the transmission mechanism to compress the air, and fresh air is supplied to the cathode gas inlet 5 through the cathode supply line 8.
[0027] Since the cathode exhaust gas from the cathode gas outlet 6 has a high moisture content, part of the moisture may be in the form of water droplets, so the cathode exhaust gas will carry water droplets. For this reason, a water separator 12 may be provided between the turbine 112 and the cathode gas outlet 6 on the cathode exhaust pipeline 9 to separate the moisture in the cathode exhaust gas. The gas after the moisture is separated enters the turbine 112, driving the turbine to rotate, so as to recycle the energy and assist in driving the air compressor 111 to work. After passing through the turbine 112, the cathode exhaust gas is discharged to the vehicle tail pipe 19.
[0028] The fuel cell system 10 may further include a cooler 13. The cooler 13 is connected to the cathode air supply line 8 downstream of the air compressor 111 to cool the pressurized air.
[0029] An air filter may be provided downstream of the air source 7 to filter the air entering the cathode 3 .
[0030] On the cathode gas supply line 8, an inlet shut-off valve 15 is provided upstream near the cathode gas inlet 5, which can be opened or closed when necessary to control the entry of cathode gas, i.e., air. On the cathode exhaust line 8, an outlet shut-off valve 16 is provided downstream of the cathode gas outlet 6, which can also be opened or closed to control the discharge of air. For example, when the system is not in operation, both the inlet judgment valve 15 and the outlet shut-off valve 16 will be closed to prevent air from entering the battery stack. In addition, for example, when various operations need to be performed on the cathode 3, such as detecting hydrogen leakage, etc., the inlet shut-off valve 15 and the outlet shut-off valve 16 of the cathode can also be closed at the same time to form a closed cavity at the cathode.
[0031] The end of the cathode exhaust line 9 leads to a vehicle tail pipe 19 to discharge the cathode exhaust gas after treatment.
[0032] A bypass valve 22 is provided between the cathode gas supply line 8 and the cathode exhaust line 9. The bypass valve 22 can be opened or closed when the fuel cell stack 1 does not need to be supplied with air or the air supply amount needs to be adjusted.
[0033] The above-mentioned inlet shut-off valve 15, outlet shut-off valve 16 and bypass valve 22 can be switch valves or regulating valves with adjustable opening, and have both on / off and flow regulation functions, but the present application is not limited thereto.
[0034] As mentioned above, in conventional fuel cell systems, the power module of a fuel cell system with a turbine has certain limitations when used in high altitude areas (low air pressure areas) and wading scenarios (high exhaust gas back pressure) that are higher than the vehicle setting value.
[0035] In high altitude areas, the intake pressure becomes lower, but due to the water-gas separator in the exhaust system and the electric air compressor-turbine structure, the working pressure of the stack cannot be reduced accordingly. This situation will increase the required air compressor pressure ratio (air compressor outlet pressure / air compressor inlet pressure), which is not conducive to the operation of the electric air compressor. If this ratio exceeds the capacity of the air compressor, the intake of the stack 1 cannot be guaranteed, which will affect the performance of the fuel cell power module in high altitude areas.
[0036] When a fuel cell vehicle is wading (for example, the tail pipe of the vehicle is at a depth of about 0.5m), the exhaust pressure of the tail pipe needs to be increased due to water entering the vehicle exhaust pipe. In this case, in order to exhaust smoothly, the air path control unit will increase the exhaust pressure of the system through the intake bypass. This will increase the power consumption of the electric air compressor. If the wading depth increases, the system cannot meet the exhaust pressure requirements, and there is a risk of water flowing into the vehicle or the fuel cell power module.
[0037] In the present application, in the fuel cell system 10, a bypass line 24 is provided on the cathode exhaust line 9, and the bypass line 24 is respectively connected between the upstream of the water separator 12 and the downstream of the turbine 112, so as to bypass or short-circuit the turbine 112 and the water separator 12, and the bypass line 24 is connected to the line where the bypass valve 22 is located. A pressure regulating device for regulating the gas flow and pressure in the bypass line 24, such as a pressure regulating valve 25, is provided on the bypass line 24, and the pressure regulating valve 25 can regulate the gas pressure and flow on the bypass line 24, and can also be completely closed and opened.
[0038] In this way, when the vehicle is traveling at a high altitude area higher than the vehicle set value, if the cathode exhaust pressure requirement can no longer be met by adjusting the outlet shut-off valve 16 alone, the pressure regulating valve 25 can be opened to short-circuit the water separator 12 of the turbine 112, so that the cathode exhaust gas discharged from the cathode 3 does not pass through the water separator 12 and the turbine 112, but directly passes through the bypass line 24 to the vehicle tail pipe 19, and the cathode exhaust gas will not be pressurized, thereby reducing the exhaust pressure.
[0039] Moreover, as the altitude increases, the gas flow in the bypass line 24 can be gradually controlled by the pressure regulating valve 25, which not only realizes the power recovery of the air compressor, but also reduces the back pressure of the fuel cell stack 1.
[0040] Similarly, when the vehicle is wading, if the cathode exhaust pressure requirement cannot be met by adjusting the outlet shut-off valve 16 alone, the pressure regulating valve 25 can also be opened to adjust the gas flow of the bypass line 24 to maintain the working pressure of the stack 1, and the overall pressure drop of the system exhaust is reduced. The system exhaust pressure is increased. In this way, the exhaust gas can be discharged to meet the normal operation requirements of the fuel cell system.
[0041] In this way, by providing the bypass line 24 and the pressure regulating valve 25, the water separator 12 and the turbine 112 in the fuel cell system are short-circuited, leaving a larger back pressure regulating space to meet the performance requirements of the fuel cell power module.
[0042] In the present application, the pressure regulating valve 25 may be an electromagnetic pressure regulating valve, but is not limited thereto. For example, the pressure regulating valve may be a regulating valve controlled by a motor or mechanically.
[0043] In addition, a flow meter for detecting the gas flow and a pressure sensor for detecting the gas pressure in the bypass line 24 may be provided in the bypass line 24 to report the gas flow and pressure in the bypass line 24 to the fuel cell control unit. The pressure regulating valve 25 is closed when the vehicle is running normally, and the cathode exhaust gas passes through the water separator 12 and the turbine 112 normally, and enters the vehicle tail pipe after being used by the turbine 112.
[0044] The pressure regulating valve 25 is opened and adjusted when the vehicle is traveling in an environment of high altitude higher than the vehicle setting value or when the vehicle is traveling through water and the cathode exhaust pressure requirement cannot be met by adjusting the outlet shut-off valve 16 alone, and the cathode exhaust gas flows directly to the vehicle tail pipe 19 through the bypass line 24. The opening of the pressure regulating valve 25 can be adjusted, thereby adjusting the exhaust pressure to the tail pipe.
[0045] The pressure regulating valve 25 can be connected to the fuel cell controller FCCU unit of the vehicle, so as to be controlled by the fuel cell controller FCCU unit to open and close and adjust the flow and pressure when necessary. The fuel cell system can also be provided with an electronic control device for controlling the opening of the pressure regulating valve according to the ambient pressure value.
[0046] The fuel cell system in the present application is not limited to the above, but can be modified in various ways according to actual needs. For example, the fuel cell system can also be provided with a pressure sensor for detecting the vehicle ambient pressure, and the pressure regulating valve is activated when the value detected by the pressure sensor is lower than a threshold.
[0047] Figure 2 The fuel cell system 10 of the second embodiment of the present application is shown in FIG. Figure 2 In addition to the different settings of the pressure regulating valve 25 and the bypass valve 22, the other Figure 1 The same as in the first embodiment shown, the same components will not be described repeatedly here, and only the components different from the first embodiment will be described.
[0048] exist Figure 2 In the second embodiment shown, instead of Figure 1The pressure regulating valve 25 and the bypass valve 22 that can be interconnected in the shown system can be integrated together to form a four-way valve 26, which is installed at the junction of the bypass line 24 and the cathode exhaust line 9, and is connected to the cathode gas supply line 8, that is, the four-way valve 26 can select the flow direction and adjust the flow rate between the bypass line 26, the cathode exhaust line 9, and the cathode gas supply line 8, thereby realizing the combined function of the pressure regulating valve 25 and the bypass valve 22 in the first embodiment.
[0049] Combine the following Figure 3 A block diagram is used to describe the cathode exhaust pressure regulation process of the fuel cell system according to the present application when the vehicle is traveling in different scenarios, especially in special circumstances such as high altitude areas higher than the vehicle setting value or wading.
[0050] like Figure 3 As shown, in step S1, the vehicle control unit determines the opening of the outlet shut-off valve 16 at the rated speed setting of the air compressor 111, and then determines in step S2 whether the exhaust pressure P of the cathode of the battery stack has reached the target exhaust pressure P required under the current driving state. target . In determining P = P target When P>P target , then enter step S4, increase the opening of the outlet shut-off valve 16 and adjust the speed of the air compressor 111 at the same time, and then determine again whether P = P target , if it is determined that P = P target , then the program ends, if P = P target If it is not established, then continue to increase the opening of the outlet shut-off valve 16 until the opening B of the outlet shut-off valve 16 reaches the maximum value B max , P=P target Then, step S5 is entered to open the pressure regulating valve 25 and adjust the opening degree, or adjust the flow direction and opening degree of the four-way valve 26 in the second embodiment so that P = P target , the adjustment process ends.
[0051] If it is determined after step S2 that P <P target When the cathode exhaust pressure needs to be increased, the opening of the outlet shut-off valve 16 is reduced in step S3 and the speed of the air compressor 111 is adjusted at the same time until P=P target until.
[0052] Although the special driving scenarios of the vehicle mentioned above are driving in high altitude areas higher than the vehicle setting value and wading, this is only an example. The embodiments of the present application can be applied to normal driving scenarios and other driving scenarios that require adjustment of the cathode exhaust pressure.
[0053] The present application has been described in detail above in conjunction with specific embodiments. Obviously, the above description and the embodiments shown in the accompanying drawings should be understood as exemplary and do not constitute a limitation to the present application. For those skilled in the art, various modifications or changes can be made to the present application without departing from the spirit of the present application, and these modifications or changes do not depart from the scope of the present application.
Claims
1. A fuel cell system, characterized in that: include: A stack having an anode and a cathode, the cathode having a cathode gas inlet and a cathode gas outlet; a cathode gas supply line for supplying cathode gas to the cathode gas inlet and a cathode exhaust line for exhausting cathode exhaust gas from the cathode gas outlet; a turbocharger located between the cathode gas supply line and the cathode exhaust line, the turbocharger comprising a turbine connected to the cathode exhaust line and an air compressor connected to the cathode gas supply line; and A water separator located between the turbine and the cathode gas outlet on the cathode exhaust line, The fuel cell system further comprises a bypass line connected between the upstream of the water separator and the downstream of the turbine and a pressure regulating device for controlling the connection and disconnection of the bypass line and regulating the fluid flow and pressure in the bypass line.
2. The fuel cell system according to claim 1, characterized in that: The pressure regulating device is a pressure regulating valve located on the bypass line.
3. The fuel cell system according to claim 2, characterized in that: The pressure regulating valve is an electromagnetic pressure regulating valve, or a regulating valve controlled by a motor or mechanically.
4. The fuel cell system according to claim 1, characterized in that: The fuel cell system further includes a bypass valve disposed between the cathode gas supply line and the cathode exhaust line.
5. The fuel cell system according to claim 1, characterized in that: The pressure regulating device is a four-way valve connecting the bypass line, the cathode gas supply line and the cathode exhaust line.
6. The fuel cell system according to any one of claims 1 to 5, characterized in that: The bypass line is also provided with a pressure sensor for detecting gas pressure.
7. The fuel cell system according to any one of claims 1 to 5, characterized in that: The pressure regulating device is closed when the vehicle is running normally, and the cathode exhaust gas enters the tail pipe of the vehicle through the water separator and the turbine.
8. The fuel cell system according to any one of claims 1 to 5, characterized in that: The pressure regulating device is opened when the vehicle is traveling in an environment higher than the vehicle's set altitude or when the vehicle is wading, and the cathode exhaust gas flows directly to the vehicle's tail pipe through the bypass line, and the exhaust pressure leading to the vehicle's tail pipe is regulated by the pressure regulating device.
9. The fuel cell system according to any one of claims 1 to 5, characterized in that: The pressure regulating device is associated with a fuel cell control unit FCCU of the vehicle and is controlled to operate by the fuel cell control unit FCCU.
10. The fuel cell system according to any one of claims 1 to 5, characterized in that: The fuel cell system is provided with a pressure sensor for detecting the pressure of the vehicle environment, and the pressure regulating device is opened when the value detected by the pressure sensor is lower than a threshold value.
11. The fuel cell system according to claim 2, characterized in that: The fuel cell system is further provided with an electronic control device for controlling the opening degree of the pressure regulating valve according to the ambient pressure value.
12. The fuel cell system according to claim 5, characterized in that: The fuel cell system is further provided with an electronic control device for controlling the opening degree of the flow direction of the four-way valve according to the ambient pressure value.