Air subsystem, method for operating air subsystem, and fuel cell system
By introducing oxygen sensors and controllers into the fuel cell system, the gas state of the cathode path is isolated and monitored, solving the gas composition problem of the fuel cell system in shutdown, standby or standby states, reducing stack degradation and hydrogen consumption, and improving system functionality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2025-10-23
- Publication Date
- 2026-04-28
AI Technical Summary
Existing fuel cell systems have difficulty effectively monitoring and controlling the gas composition in the cathode path during shutdown, shutdown, or standby states, leading to stack degradation and increased hydrogen consumption.
An oxygen sensor is introduced into the fuel cell system. The fuel cell stack is isolated from the intake and exhaust paths by shut-off valves in the intake and exhaust paths. An oxygen sensor is also placed in the cathode path to monitor the gas state. The system is then combined with a controller and computer program for real-time adjustment and control.
It enables effective monitoring and control of the cathode path during shutdown, stoppage, or standby states, reducing reactor degradation and hydrogen consumption, and improving system functionality and efficiency.
Smart Images
Figure CN121938962A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an air subsystem for a fuel cell system, a method for operating the air subsystem, and a fuel cell system. The subject matter of this invention also relates to a computer program. Background Technology
[0002] For vehicles, such as so-called fuel cell vehicles (FCVs), the driving energy is also provided by one or more fuel cell systems (FCS), which typically use oxygen from ambient air as an oxidant to react with hydrogen in the fuel cell to produce water or water vapor, thereby providing electrical power through electrochemical conversion. The cathode exhaust is oxygen-deficient due to this reaction. In cases where the oxygen has completely reacted, the exhaust may also contain only nitrogen and water or water vapor. To monitor these reactions, sensors are typically used in the exhaust path. Oxygen concentration sensors, which determine the oxygen content in the gas mixture, are typically used in the exhaust path, downstream of the stack outlet valve, or in the exhaust recirculation path. Summary of the Invention
[0003] Against this backdrop, the proposed solution provides an improved air subsystem for a fuel cell system, an improved method for operating the air subsystem, a controller using the method, an improved fuel cell system, and a corresponding computer program. Advantageous extensions and improvements to the apparatus according to the invention can be achieved through the measures listed in the specification.
[0004] The proposed scheme creates the possibility of monitoring, regulating, and / or controlling the gas composition of the fuel cell system stack or stacked in the cathode path during shutdown, such as standby or shutdown, and during shutdown and startup. Advantageously, this can minimize stack degradation and save hydrogen in particular.
[0005] An air subsystem for a fuel cell system is proposed, wherein the air subsystem has an intake path for supplying intake air to the fuel cell system. The intake path includes a first shut-off valve. Furthermore, the air subsystem has an exhaust path for discharging exhaust gas from the fuel cell system, wherein the exhaust path includes a second shut-off valve. Additionally, the air subsystem has a fuel cell stack coupled to the first shut-off valve on the input side via a first connection terminal and to the second shut-off valve on the output side via a second connection terminal, and the air subsystem has at least one oxygen sensor arranged in a cathode path. The cathode path extends between the first and second shut-off valves and extends through the fuel cell stack.
[0006] The fuel cell system can be used, for example, in a vehicle, such as a passenger car. The fuel cell system can have, for example, multiple subsystems, of which an air subsystem may be one. Intake air, such as ambient air, can be supplied via an intake path. The intake air supply can be regulated, stopped, or released using a first shut-off valve. Therefore, exhaust emissions downstream of the fuel cell stack can be regulated, stopped, or released via a second shut-off valve. The shut-off valves can isolate or connect the fuel cell stack to the intake and exhaust paths. The fuel cell stack can, for example, have multiple fuel cells, which can have an anode, a cathode, and a membrane located therebetween. An oxygen sensor can be arranged within the cathode path. Therefore, the air subsystem can have an air path consisting of an intake path, a cathode path, and an exhaust path. Advantageously, by the proposed scheme and therefore by the location of the oxygen sensor, the gas state within the cathode path, which can be closed or has been closed by the shut-off valve, can be monitored, and thus the overall functionality of the fuel cell system can be improved, thereby reducing degradation in the stack. Furthermore, air-to-air start can be avoided, and on-demand control or regulation of the system can be adapted. Overall, it can also reduce hydrogen consumption in fuel cell systems.
[0007] The at least one oxygen sensor can be configured to determine the oxygen content of the gas mixture guided in the air subsystem. The at least one oxygen sensor can be used for regulating, monitoring, or diagnosing the fuel cell reaction, or for regulating, monitoring, or diagnosing exhaust gas recirculation (EGR). EGR returns a portion of the exhaust gas to the intake path and is used for various purposes, particularly for humidifying the intake air and / or for reducing the oxygen content of the intake air or increasing the flow rate in the stack without increasing the oxygen supply. Furthermore, the at least one oxygen sensor can be used for regulating, monitoring, or diagnosing inerting or inert gas generation through the stack. Here, inert gas can be used for inerting both the cathode and anode regions. Additionally, the at least one oxygen sensor can be used to measure ambient air, such as humidity or oxygen content.
[0008] According to one embodiment, the oxygen sensor can be disposed between the first shut-off valve and the first connection terminal. Advantageously, the gas composition or oxygen fraction can be detected simply, accurately, and reliably, thereby improving the functionality of the fuel cell system.
[0009] Furthermore, the oxygen sensor can be positioned between the second shut-off valve and the second connection terminal. Advantageously, this also allows for early detection of oxygen content, enabling the fuel cell system to react directly, for example, when the oxygen content is too high or too low. Advantageously, the gas composition or oxygen fraction can be detected simply, accurately, and reliably, thereby improving the functionality of the fuel cell system.
[0010] The oxygen sensor can be arranged inside the fuel cell stack, particularly in the distribution channels of the fuel cell stack. More precisely, the fuel cell stack can have multiple distribution channels. The oxygen sensor can be arranged in one of these distribution channels. Being inside the fuel cell stack advantageously means that the oxygen sensor can be arranged between the first connection terminal and the second connection terminal. Advantageously, the gas composition or oxygen fraction can be detected simply, accurately, and reliably, thereby improving the functionality of the fuel cell system.
[0011] According to one embodiment, the oxygen sensor can be implemented as a lambda-sonde probe. Advantageously, the efficiency of the fuel cell system can be improved by using a lambda-sonde probe because it enables robust and reliable oxygen detection.
[0012] A method for operating the air subsystem in the aforementioned variant is also proposed. The method includes: reading sensor data from an oxygen sensor via an interface, wherein the sensor data represents an actual oxygen value in the air subsystem; comparing the sensor data with reference data representing a target oxygen value to obtain a comparison result, the comparison result representing the difference between the actual oxygen value and the target oxygen value; and controlling at least one component of the fuel cell system based on the comparison result.
[0013] According to one embodiment, the read-in step, the comparison step, and / or additional or alternative control steps can be performed during the startup process, normal operation, shutdown process, standby state, and / or additional or alternative shutdown of the fuel cell system. Thus, it is also advantageous to perform and monitor the shutdown process (e.g., depressurization), the shutdown phase, the standby phase (including wake-up), and the startup process.
[0014] Advantageously, by means of the proposed scheme and therefore the use and location of an oxygen sensor, the gas state within the cathode path, which may be closed or has been closed by a shut-off valve, can be monitored, thus improving the overall functionality of the fuel cell system. Consequently, the methods and functionality during shutdown / shutdown (e.g., depressurization), during shutdown and standby (including wake-up), and during startup can also be improved. Furthermore, diagnostics and rationale checks can also be improved. For example, hydrogen consumption can be reduced. Moreover, by monitoring the gas state during operation, the components can be manipulated to, for example, enable on-demand hydrogen replenishment to the anode of the fuel cell system.
[0015] This method can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, such as in a controller.
[0016] The proposed solution also provides a controller configured to perform, manipulate, or implement a variation of the method presented herein in a suitable device. This controller-based implementation of the invention also allows for a rapid and efficient solution to the task on which the invention is based.
[0017] To this end, the controller may have at least one computing unit for processing signals or data, at least one storage unit for storing signals or data, at least one interface connected to a sensor or actuator for reading sensor signals from the sensor or outputting control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The computing unit may be, for example, a signal processor, a microcontroller, etc., and the storage unit may be a flash memory or magnetic storage unit. The communication interface may be configured for wirelessly and / or wiredly reading or outputting data, wherein a communication interface capable of wired data reading or outputting data may, for example, electrically or optically read or output such data to a corresponding data transmission line.
[0018] Here, a controller can be understood as an electrical device that processes sensor signals and outputs control and / or data signals accordingly. The controller may have an interface, which can be constructed in hardware and / or software. In the case of a hardware construction, the interface may be, for example, part of a so-called system ASIC, which incorporates various functions of the controller. However, it is also possible that the interface is a separate integrated circuit or at least partially composed of discrete components. In the case of a software construction, the interface may be a software module, for example, existing alongside other software modules on a microcontroller.
[0019] Furthermore, a fuel cell system is proposed, which has an air subsystem and a controller as described in the aforementioned variant, wherein the controller is connected to the oxygen sensor of the air subsystem in a data-transferring manner.
[0020] Advantageously, the fuel cell system can be used in a vehicle. The air subsystem can be coupled to the cathode of the fuel cell system. The controller preferably operates at least one component of the fuel cell system.
[0021] It is also advantageous to have a computer program product or computer program having program code that can be stored on a machine-readable carrier or storage medium, such as semiconductor memory, hard disk memory or optical memory, and for performing, implementing and / or manipulating the steps of a method according to one of the foregoing embodiments, especially when the program product or program is implemented on a computer or device. Attached Figure Description
[0022] Embodiments of the proposed solution are shown in the accompanying drawings and further described below. Wherein are shown: Figure 1 A schematic diagram showing one embodiment of a fuel cell system is shown; Figure 2 A schematic diagram showing one embodiment of the air subsystem; Figure 3 A flowchart illustrating one embodiment of a method for operating an air subsystem; and Figure 4 A schematic diagram of a controller according to one embodiment is shown.
[0023] In the following description of advantageous embodiments of the invention, the same or similar reference numerals are used for elements shown in different figures and that function similarly, and repeated descriptions of these elements are omitted. Detailed Implementation
[0024] Figure 1 A schematic diagram of an embodiment of a fuel cell system 100 is shown. This fuel cell system 100 is used, for example, in vehicles, such as passenger cars, but also in commercial vehicles or heavy-duty trucks. For example, the fuel cell system 100 can be used in various vehicle categories, such as on-road vehicles, off-road vehicles, commercial vehicles, and / or buses equipped with a fuel cell system.
[0025] The fuel cell system 100 includes an air subsystem 105 and a controller 110, wherein the controller 110 is connected to an oxygen sensor 115 of the air subsystem 105 in a data-transferring manner. The oxygen sensor 115 is arranged inside the cathode path of the fuel cell system 100, such as... Figure 2 The details are elaborated below. The oxygen sensor 115 is implemented, for example, as a λ probe.
[0026] Furthermore, according to this embodiment, the controller 110 is signal-transmittingly connected to component 120 of the fuel cell system 100. More precisely, the controller 110 is configured to operate component 120 in a method for operating the air subsystem 105. Figure 3 Detailed description is provided below. Component 120 may be implemented as part of air subsystem 105, or, for example, as an external component of air subsystem 105, however, the external component is required to operate fuel cell system 100 or at least one of its functions.
[0027] Figure 2 A schematic diagram of an embodiment of the air subsystem 105 is shown, which, for example, corresponds to... Figure 1 The air subsystem described in [the text]. For example... Figure 1As described above, the air subsystem 105 is implemented as part of a fuel cell system, such as the fuel cell system in... Figure 1 As described in the text.
[0028] The air subsystem 105 has an intake path 200 for supplying intake air to the fuel cell system, wherein the intake path 200 includes a first shut-off valve 205. Furthermore, the air subsystem 105 has an exhaust path 210 for discharging exhaust gas from the fuel cell system, wherein the exhaust path 210 includes a second shut-off valve 215. The air subsystem 105 also has a fuel cell stack 220, which is coupled to the first shut-off valve 205 on the input side via a first connection terminal 225 and to the second shut-off valve 215 on the output side via a second connection terminal 230. In particular, the fuel cell stack 220 has a plurality of fuel cells. The air subsystem 105 also has at least one oxygen sensor 115 arranged in a cathode path 235. The cathode path 235 extends between the first shut-off valve 205 and the second shut-off valve 215 and extends through the fuel cell stack 220. The intake path 200, the cathode path 235 and the exhaust path together constitute the air path, wherein the cathode path 235 extends in the area blocked by the shut-off valves 205 and 215.
[0029] Advantageously, the position of the oxygen sensor 115 within the cathode path 235 is variable during assembly. For example, the oxygen sensor 115 may be arranged between the first shut-off valve 205 and the first connection end 225. Alternatively, the oxygen sensor 115 may be arranged inside the fuel cell stack 220, particularly in the distribution channels of the fuel cell stack 220. The fuel cell stack 220, for example, has multiple distribution channels. According to this embodiment, the oxygen sensor 115 is arranged between the second shut-off valve 215 and the second connection end 230. For example, the oxygen sensor 115 is implemented or can be implemented as a λ probe.
[0030] According to one embodiment, the intake path 200 further includes an air compressor, and / or the exhaust path 210 includes a turbine and / or at least one additional valve.
[0031] According to one embodiment, the intake path 200 has a first bypass connection 240, and the exhaust path 210 has a second bypass connection 245 coupled to the first bypass connection 240. According to this embodiment, a bypass valve 250 is arranged between the bypass connections 240 and 245 to bypass the fuel cell stack 220 when necessary. Furthermore, according to this embodiment, the air subsystem 105 has an exhaust gas recirculation path 255 (EGR). The EGR returns a portion of the exhaust gas to the intake path 200 for various purposes, particularly for humidifying the intake air and / or for reducing the oxygen content of the intake air or increasing the flow rate in the stack without increasing the oxygen supply.
[0032] In other words, the at least one oxygen sensor 115 is arranged in a sealable cathode volume (described herein as cathode path 235), between the fuel cell stack 220 (also referred to as stack 220) and shut-off valves 205, 215, or in the stack distribution channel, to enable additional system functions. Such functions include, for example, monitoring the bleed-down process (meaning oxygen depletion) during or after stack 220 shutdown, and / or, particularly during shutdown or standby, monitoring the gas state in the closed cathode path 235. Various triggers for these functions can be derived, such as triggers for on-demand hydrogen replenishment of the anode, or triggers for on-demand inerting or re-inerting. Furthermore, the actual O2 partial pressure at stack 220 startup is ensured, and / or the required anode flushing time can be pre-controlled based on the actual gas composition.
[0033] In summary, the oxygen sensor 115 is disposed within a sealably closed cathode path 235, specifically between the first shut-off valve 205 and the second shut-off valve 215, both of which include a sealing function. Preferably, the oxygen sensor 115 is disposed between the stack outlet, described as the second connection end 230, and the downstream second shut-off valve 215. Alternatively, the oxygen sensor 115 may also be integrated into the stack 220, for example, into the collector of the cathode path 235.
[0034] Therefore, during or after reactor 220 shutdown, or when transitioning to standby or shutdown after closing cathode valves 205 and 215 located before or after reactor 220, monitoring of the depressurization process (oxygen depletion) can be achieved. This also allows for the decompression trigger to terminate the depressurization process. Furthermore, the depressurization process can be prevented from entering an excessively long proton pumping phase, such as when oxygen is consumed and current continues to be drawn. This means hydrogen consumption is minimized. Additionally, monitoring of the gas state of the enclosed cathode path 235 regarding oxygen infiltration is achieved, for example, when reactor 220 is shut down in a shutdown or standby state. This allows for the decompression trigger to be derived for various functions, such as triggers for wake-up functions during shutdown or standby. Such triggers, for example, trigger the replenishment of hydrogen to the anode. Therefore, to avoid hydrogen depletion and oxygen infiltration into the anode, hydrogen can be replenished to the anode as needed. Furthermore, such triggers can trigger re-inerting. If stack 220 is in a shutdown or standby state for an extended period of time, re-inertization can be performed, for example, by another stack or by additional depressurization.
[0035] According to one embodiment, the actual O2 partial pressure during stack startup is also ensured. This means that during stack 220 startup, the air subsystem 105 should be filled with sufficient oxygen before drawing the corresponding current or power from stack 220. A trigger for drawing current is determined using the oxygen sensor 115. Furthermore, it is ensured that current is not drawn prematurely, i.e., when oxygen is insufficient or the O2 partial pressure is too low.
[0036] Furthermore, the required flushing time is pre-controlled based on the actual gas composition. During startup, if the oxygen sensor 115 has previously determined the state of the closed volume, i.e., the cathode path 235, the anode flushing can be more targeted, meaning purging or replenishing with hydrogen. Due to the presence of sensor 115, these functions can be applied throughout its service life or adapted to the system state.
[0037] Figure 3 A flowchart is shown of an embodiment of a method 300 for operating an air subsystem, such as in... Figure 1 and Figure 2 At least one of these is described or mentioned. Method 300 includes a read-in step 305, a comparison step 310, and a manipulation step 315. In the read-in step 305, sensor data is read from an oxygen sensor via an interface, wherein the sensor data represents the actual oxygen value in the air subsystem. In the comparison step 310, the sensor data is compared with reference data representing a target oxygen value to obtain a comparison result representing the difference between the actual oxygen value and the target oxygen value. In the manipulation step 315, at least one component of the fuel cell system is manipulated based on the comparison result.
[0038] For example, the read-in step 305, the comparison step 310, and / or the control step 315 are performed during the startup process, normal operation, shutdown process, preparation state, and / or shutdown of the fuel cell system.
[0039] Figure 4 A schematic diagram of one embodiment of controller 110 is shown, which corresponds, for example, to... Figure 1 The controller described herein. Controller 110 is configured to manipulate and / or execute methods for operating the air subsystem, such as... Figure 3 The method described herein. According to this embodiment, the controller 110 has a read-in unit 400, a comparison unit 405, and a control unit 410.
[0040] The read-in unit 400 is configured to read sensor data 415 from the oxygen sensor 115 via an interface. Sensor data 415 represents the actual oxygen value in the air subsystem. The comparison unit 405 is configured to compare the sensor data 415 with reference data 420 representing a target oxygen value to obtain a comparison result 425, which represents the difference between the actual oxygen value and the target oxygen value. The control unit 410 is configured to control at least one component of the fuel cell system based on the comparison result 425, for example, by using a control signal 430.
[0041] If an embodiment includes an "and / or" connection between a first feature and a second feature, it should be understood that: according to one implementation, the embodiment has both the first feature and the second feature, and according to another implementation, the embodiment has either only the first feature or only the second feature.
Claims
1. An air subsystem (105) for a fuel cell system (100), wherein, The air subsystem (105) has the following characteristics: - An intake path (200) for supplying intake air to the fuel cell system (100), wherein the intake path (200) includes a first shut-off valve (205). - Exhaust path (210) for discharging exhaust gas from the fuel cell system (100), wherein the exhaust path (210) includes a second shut-off valve (215). - A fuel cell stack (220), which is coupled to a first shut-off valve (205) on the input side via a first connection terminal (225) and to a second shut-off valve (215) on the output side via a second connection terminal (230); and - At least one oxygen sensor (115) is arranged in a cathode path (235) that extends between the first shut-off valve (205) and the second shut-off valve (215) and through the fuel cell stack (220).
2. The air subsystem (105) according to claim 1, wherein, The oxygen sensor (115) is arranged between the first shut-off valve (205) and the first connection end (225).
3. The air subsystem (105) according to any one of the preceding claims, wherein, The oxygen sensor (115) is arranged between the second shut-off valve (215) and the second connection end (230).
4. The air subsystem (105) according to any one of the preceding claims, wherein, The oxygen sensor (115) is arranged inside the fuel cell stack (220), and in particular, the oxygen sensor (115) is arranged in the distribution channel of the fuel cell stack (220).
5. The air subsystem (105) according to any one of the preceding claims, wherein, The oxygen sensor (115) is implemented as a λ probe.
6. A method (300) for operating an air subsystem (105) according to any one of the preceding claims, wherein, The method (300) includes the following steps: - Sensor data (415) is read (305) from the oxygen sensor (115) via an interface, wherein the sensor data (415) represents the actual oxygen value in the air subsystem (105); - The sensor data (415) is compared (310) with reference data (420) representing the target oxygen value to obtain a comparison result (425), the comparison result representing the difference between the actual oxygen value and the target oxygen value; and - Based on the comparison result (425), operate (315) at least one component (120) of the fuel cell system (100).
7. The method (300) according to claim 6, wherein, The steps of reading in (305), comparing (310), and / or manipulating (315) are performed during the startup, normal operation, shutdown, preparation, and / or shutdown of the fuel cell system (100).
8. A controller (110) configured to implement and / or manipulate the steps (305, 310, 315) of the method (300) according to claim 7 in respective units (400, 405, 410).
9. A fuel cell system (100) having the following characteristics: - The air subsystem (105) according to any one of claims 1 to 5; and - The controller (110) according to claim 8, wherein, The controller (110) is connected to the oxygen sensor (115) of the air subsystem (105) in a data transmission manner.
10. A computer program configured to perform and / or manipulate steps (305, 310, 315) of the method (300) according to claim 6 or 7.
11. A machine-readable storage medium having a computer program as claimed in claim 10 stored thereon.