A fuel cell hydrogen supply system and a monitoring method for monitoring purity on-line

Abstract

The application provides a fuel cell hydrogen supply system and a monitoring method for monitoring purity online. The fuel cell has high requirements for hydrogen purity, and low hydrogen purity will lead to low single piece voltage of the fuel cell stack. However, low hydrogen purity is only one possible reason for low single piece voltage, and when the fault of low single piece voltage occurs, if no hydrogen purity detection device is provided, the fault reason cannot be quickly checked and determined. The fuel cell hydrogen supply system for monitoring purity online provided by the application realizes real-time online monitoring of hydrogen purity without the hydrogen purity detection device, so that the fuel cell system can quickly check the fault reason, and the reliability and practicality of the fuel cell system are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fuel cell, and particularly relates to a fuel cell hydrogen supply system and a monitoring method for monitoring purity on line. BACKGROUND

[0002] Fuel cell engines are widely applied to passenger cars and large vehicles such as trucks due to high efficiency, low environmental pollution, high specific energy and low noise.

[0003] Fuel cells have high requirements for hydrogen purity. When the hydrogen purity supplied by the hydrogen system does not meet the requirements of the fuel cell system, the fuel cell system is prone to have a low single-cell voltage fault. However, there are many reasons for the low single-cell voltage of the fuel cell system, and low hydrogen purity is only one of them. In the case where the hydrogen purity cannot be effectively monitored, it is difficult to lock the fault cause, and a large amount of manpower and material resources are required for fault troubleshooting.

[0004] An easily thought solution is to set a hydrogen purity monitoring sensor in the hydrogen supply system of the fuel cell. However, this solution introduces an additional detection device, increases the complexity and cost of the system, and is only suitable for laboratory scenarios, but not for actual application occasions of the fuel cell. Therefore, it is urgent to provide a system and method for effectively monitoring hydrogen purity without increasing the complexity of the fuel cell system. SUMMARY

[0005] In view of the problems in the prior art, the present application provides a fuel cell hydrogen supply system and a monitoring method for monitoring purity on line.

[0006] In a first aspect, the present application provides a fuel cell hydrogen supply system for monitoring purity on line, comprising a hydrogen supply pipeline, a hydrogen backflow pipeline and a data processing unit, wherein:

[0007] The hydrogen supply pipeline is provided with a hydrogen injector, an ejector and an inlet hydrogen pressure sensor, and is configured to supply hydrogen to the anode of a fuel cell stack;

[0008] The hydrogen backflow pipeline is provided with a gas-liquid separator and a backflow hydrogen pressure sensor, and is configured to transport the residual hydrogen in the anode tail gas to the backflow gas inlet of the ejector to re-enter the fuel cell stack for reaction;

[0009] The data processing unit is configured to receive the inlet hydrogen pressure collected by the inlet hydrogen pressure sensor and the backflow hydrogen pressure collected by the backflow hydrogen pressure sensor, and obtain a monitoring result by calculating and processing the inlet hydrogen pressure and the backflow hydrogen pressure.

[0010] Further, a safety valve is arranged on the hydrogen supply pipeline.

[0011] Further, an exhaust branch is connected to the hydrogen backflow pipeline, and an exhaust valve is arranged on the exhaust branch.

[0012] The data processing unit can process the inlet hydrogen pressure and the backflow hydrogen pressure in various ways to obtain the monitoring result. For example, the data processing unit can calculate the difference between the inlet hydrogen pressure and the backflow hydrogen pressure, compare the difference with a preset threshold value stored in the data processing unit, and thus obtain the monitoring result.

[0013] In the second aspect, the application provides a monitoring method for monitoring the hydrogen purity of a fuel cell hydrogen supply system, comprising:

[0014] S1: collecting the inlet hydrogen pressure by means of an inlet hydrogen pressure sensor and collecting the backflow hydrogen pressure by means of a backflow hydrogen pressure sensor;

[0015] S2: transmitting the inlet hydrogen pressure and the backflow hydrogen pressure to a data processing unit; and processing the inlet hydrogen pressure and the backflow hydrogen pressure to obtain a monitoring result.

[0016] Specifically, in step S2, the inlet hydrogen pressure and the backflow hydrogen pressure can be processed in various ways to obtain the monitoring result. For example, the difference between the inlet hydrogen pressure and the backflow hydrogen pressure is calculated, and the difference is compared with a preset threshold value stored in the data processing unit, so as to obtain the monitoring result.

[0017] Further, although the above monitoring method can be implemented in different operating states of the fuel cell stack, the inventors have found that, compared with the normal current density state or the high current density state, if the hydrogen purity is abnormal when the fuel cell stack is in the low current density state, the data relationship between the inlet hydrogen pressure and the backflow hydrogen pressure will deviate more greatly from the preset threshold value, so that more accurate monitoring and identification can be achieved. Therefore, the above monitoring method is preferably implemented when the fuel cell stack is in the low current density state.

[0018] The fuel cell hydrogen supply system and the monitoring method for monitoring the purity provided by the application can realize real-time online monitoring of the hydrogen purity without arranging a hydrogen purity monitoring sensor, so that the fuel cell system can quickly identify the fault cause, and the reliability and practicability of the fuel cell system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the figures, exemplary embodiments of the present disclosure.

[0020] Figure 1 A fuel cell hydrogen supply system for online monitoring of purity is shown in an embodiment.

[0021] Reference signs: 1-hydrogen supply line; 2-hydrogen backflow line; 3-data processing unit; 4-fuel cell stack; 11-hydrogen ejector; 12-ejector; 13-inlet stack hydrogen pressure sensor; 14-safety valve; 21-gas-liquid separator; 22-backflow hydrogen pressure sensor; 23-exhaust valve. DETAILED DESCRIPTION

[0022] Embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these exemplary embodiments are provided so that the present disclosure will be more thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0023] The term "comprising" and variations thereof as used herein are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Unless otherwise specified, the term "or" as used herein is intended to mean "and / or", i.e., to include any and all combinations of one or more of the associated listed items. The term "based on" means "based, at least in part, on". The term "connected" means directly or indirectly connected or linked via another component. The terms "first", "second", and the like, do not necessarily denote any order, quantity, or importance, but are used to identify individual elements. Other explicit and implicit definitions can also be included below.

[0024] As Figure 1 The specific embodiment of the present disclosure provides a fuel cell hydrogen supply system for online monitoring of purity, mainly including a hydrogen supply line 1, a hydrogen backflow line 2, and a data processing unit 3.

[0025] The main function of the hydrogen supply line 1 is to provide hydrogen to the anode of the fuel cell stack 4. The fuel cell stack 4 is the core component of the fuel cell system, and is the main place for the electrochemical reaction of hydrogen and air (oxygen). The specific type of fuel cell stack 4 is not particularly limited in this embodiment, which can be a proton exchange membrane fuel cell stack, a solid oxide fuel cell stack, or a molten carbonate fuel cell stack. Other lines and supporting components connected to the fuel cell stack 4 are not the focus of the present invention and are not particularly limited in the present invention.

[0026] The main components of the hydrogen supply pipeline 1 include a hydrogen injector 11, an ejector 12, a hydrogen pressure sensor 13, and a safety valve 14. The hydrogen injector 11 and ejector 12 are crucial for realizing the recirculation of anode exhaust gas from the fuel cell stack 4. The main component of the anode exhaust gas discharged from the fuel cell stack 4 is water vapor, but it also includes residual hydrogen. A high-speed jet of hydrogen is injected into the ejector 12 via the hydrogen injector 11, creating a pressure difference between the ejector 12 and the hydrogen recirculation pipeline 3. Driven by this pressure difference, the residual hydrogen in the hydrogen recirculation pipeline 3 enters the ejector 12 and mixes with the high-speed hydrogen jet, before re-entering the fuel cell stack 4 to participate in the reaction.

[0027] The main function of the hydrogen reflux line 2 is to transport the residual hydrogen in the anode tail gas to the reflux gas inlet of the ejector 12, so that it can re-enter the fuel cell stack for reaction. As a key component of the hydrogen reflux line 2, it is equipped with a gas-liquid separator 21 and a reflux hydrogen pressure sensor 22. The hydrogen reflux line 2 is also connected to an exhaust branch, on which an exhaust valve 23 is installed.

[0028] Monitoring the purity of hydrogen entering the fuel cell stack 4 is generally considered difficult without a hydrogen purity monitoring sensor. However, the fuel cell hydrogen supply system provided in this specific embodiment has a data processing unit 3, which is connected to the infeed hydrogen pressure sensor 13 and the return hydrogen pressure sensor 22. The data processing unit 3 is configured to receive the infeed hydrogen pressure collected by the infeed hydrogen pressure sensor 13 and the return hydrogen pressure collected by the return hydrogen pressure sensor 22, and to obtain the monitoring result by calculating and processing the infeed hydrogen pressure and the return hydrogen pressure.

[0029] For specific calculation and processing methods, various data processing methods can be used, as long as they can reflect the change in the numerical relationship between the hydrogen purity change and the infeed hydrogen pressure and the reflux hydrogen pressure. For example, the difference between the infeed hydrogen pressure and the reflux hydrogen pressure can be calculated, and this difference can be compared with a preset threshold stored in the data processing unit to obtain the monitoring result.

[0030] The preset threshold is a benchmark for measuring the calculation results, and can be obtained through various methods such as measurement in a laboratory environment, calculation by theoretical formula, or determination based on actual operating data statistics.

[0031] based on Figure 1 The present invention also provides a monitoring method for an online fuel cell hydrogen supply system for monitoring purity, comprising:

[0032] S1: collecting the inlet hydrogen pressure by the inlet hydrogen pressure sensor 13 and collecting the backflow hydrogen pressure by the backflow hydrogen pressure sensor 22;

[0033] S2: transmitting the inlet hydrogen pressure and the backflow hydrogen pressure to the data processing unit 3; obtaining the monitoring result by calculating the inlet hydrogen pressure and the backflow hydrogen pressure.

[0034] Specifically, in step S2, the difference between the inlet hydrogen pressure and the backflow hydrogen pressure is calculated, and the difference is compared with the preset threshold value stored in the data processing unit 3, so as to obtain the monitoring result: when the difference is lower than the preset threshold value, it is determined that the hydrogen purity is lower than the standard value, and at this time, the hydrogen purity problem is the main cause of the low single cell voltage of the fuel cell stack.

[0035] Having described various embodiments of the disclosure above, those skilled in the art will appreciate that the above description is merely exemplary and is not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles, practical applications, or improvements to the prior art of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A fuel cell hydrogen supply system for on-line purity monitoring, characterized by, The system comprises a hydrogen supply pipeline, a hydrogen backflow pipeline and a data processing unit, wherein: The hydrogen supply pipeline is provided with a hydrogen injector, an ejector and an inlet hydrogen pressure sensor, and is configured to supply hydrogen to the anode of the fuel cell stack; The hydrogen backflow pipeline is provided with a gas-liquid separator and a backflow hydrogen pressure sensor, and is configured to transport the residual hydrogen in the anode tail gas to the backflow gas inlet of the ejector to re-enter the fuel cell stack for reaction; The data processing unit is in data connection with the inlet hydrogen pressure sensor and the backflow hydrogen pressure sensor, and is configured to receive the inlet hydrogen pressure collected by the inlet hydrogen pressure sensor and the backflow hydrogen pressure collected by the backflow hydrogen pressure sensor, and obtain a monitoring result by calculating the difference between the inlet hydrogen pressure and the backflow hydrogen pressure, and comparing the difference with a preset threshold value stored in the data processing unit; the monitoring method is implemented when the fuel cell stack is in a low current density state; The hydrogen supply pipeline is provided with a safety valve.

2. A fuel cell hydrogen supply system for on-line purity monitoring according to claim 1, wherein The hydrogen backflow pipeline is connected with an exhaust branch, and the exhaust branch is provided with an exhaust valve.

3. A method of monitoring the purity of hydrogen in a hydrogen supply system for a fuel cell, the method comprising, The fuel cell hydrogen supply system is selected from the fuel cell hydrogen supply system for online monitoring of purity according to any one of claims 1-2, and the monitoring method comprises the following steps: S1: collecting the inlet hydrogen pressure by the inlet hydrogen pressure sensor and the backflow hydrogen pressure by the backflow hydrogen pressure sensor; S2: transmitting the inlet hydrogen pressure and the backflow hydrogen pressure to the data processing unit; obtaining a monitoring result by calculating the difference between the inlet hydrogen pressure and the backflow hydrogen pressure, and comparing the difference with a preset threshold value stored in the data processing unit; the monitoring method is implemented when the fuel cell stack is in a low current density state.

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