A fuel cell hydrogen assisted circulation system and a control method thereof

Abstract

The application discloses a kind of fuel cell hydrogen auxiliary circulation system and its control method, it is related to fuel cell system technical field, including hydrogen storage bottle, pressure reducing valve and proportional valve connected in turn, proportional valve is connected by pipeline into electric pile and controls into the air of electric pile, electric pile air inlet end is connected air compressor, air compressor is connected with first valve and electric pile, air pipe of electric pile is sequentially connected with second valve, first gas-water separator and is discharged into atmosphere after through steam turbine device, hydrogen pipe of electric pile is connected with second gas-water separator and enters electric pile after through steam turbine device, wherein, first valve is connected by pipeline into steam turbine device, second gas-water separator is connected with third valve, compared with prior art, on the basis of not increasing additional structure and equipment, using the operating characteristics of fuel cell system air path under low power and high power operating conditions, hydrogen auxiliary circulation is completed using air pressure energy by steam turbine structure, and the working characteristics of fuel cell system air path is reasonably utilized.

Description

Technical Field

[0001] This invention relates to the field of fuel cell system technology, and specifically to a fuel cell hydrogen auxiliary circulation system and its control method. Background Technology

[0002] The fuel cell system provides the necessary conditions for the normal operation of the fuel cell stack and mainly includes an air supply subsystem, a hydrogen recirculation subsystem, and a hydrothermal management subsystem. The hydrogen recirculation subsystem continuously supplies high-purity hydrogen to the stack at a certain pressure and flow rate, ensuring the normal progress of the electrochemical reactions within the fuel cell stack. Hydrogen recirculation technology returns unreacted fuel to the fuel cell while separating excess impurities and water. This not only increases fuel utilization but also effectively improves issues such as anode water blockage, uneven hydrogen distribution, and hydrogen permeation in the fuel cell stack, thereby enhancing fuel cell performance and reliability.

[0003] Hydrogen recirculation pumps can actively regulate the hydrogen return flow rate, but they are generally driven by an electric motor, consuming power during operation, accounting for 3% to 5% of parasitic power. Existing technologies use high-pressure hydrogen to directly drive the hydrogen recirculation pump through an expander, which can improve system energy utilization. However, if the hydrogen flow rate is too low, it is difficult to drive the hydrogen recirculation pump to operate normally, and the hydrogen return flow rate cannot be actively adjusted during operation. Therefore, how to utilize the characteristics of hydrogen fuel cell systems to assist hydrogen recirculation without increasing additional power is a pressing problem that needs to be solved. Summary of the Invention

[0004] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a fuel cell hydrogen auxiliary circulation system and its control method, which aims to solve the technical problems in the related technology to a certain extent.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A hydrogen auxiliary circulation system for a fuel cell includes a hydrogen storage tank, a pressure reducing valve, and a proportional valve connected in sequence. The proportional valve is connected to the fuel cell stack via a pipeline and controls the hydrogen entering the stack. The air inlet of the fuel cell stack is connected to an air compressor. The air compressor is connected to a first valve and the fuel cell stack. The air outlet pipeline is connected in sequence to a second valve, a first gas-liquid separator, and then discharged into the atmosphere through a turbine unit. The hydrogen outlet pipeline is connected to a second gas-liquid separator and then enters the fuel cell stack through the turbine unit. The first valve is connected to the turbine unit via a pipeline, and the second gas-liquid separator is connected to a third valve.

[0007] Based on the above technical solution, the steam turbine unit is equipped with a driving turbine and a driven turbine, wherein the driving turbine is connected to the air exhaust and the driven turbine is connected to the hydrogen circulation loop.

[0008] Based on the above technical solution, the pressure reducing valve is a gas pressure reducing valve, and the proportional valve is an electromagnetic proportional valve.

[0009] Based on the above technical solution, the first gas-water separator and the second gas-water separator are one or a combination of two of the following: tubular separator, louvered separator, and cyclone separator.

[0010] Based on the above technical solutions, the air compressor is a centrifugal air compressor or a screw air compressor.

[0011] Based on the above technical solution, the first valve, the second valve, and the third valve are pneumatic switching valves, electric switching valves, or a combination of pneumatic switching valves and electric switching valves, and the third valve controls the amount of liquid water stored in the second gas-water separator, or the second valve and the third valve are throttle valves.

[0012] Based on the above technical solution, a control method for a fuel cell hydrogen auxiliary circulation system includes the following steps:

[0013] S1. The fuel cell stack starts up, and the auxiliary circulation system begins to work;

[0014] S2. Determine whether the current power of the fuel cell stack is in the auxiliary cycle control segment according to the set operating conditions. If yes, determine whether the current power of the fuel cell stack is in the initial power segment auxiliary cycle and proceed to the next step S3. If not, keep the first valve and the second valve closed and proceed to S4.

[0015] S3. Simultaneously control the opening degree of the first valve and the second valve;

[0016] S4. Determine whether the current power of the fuel cell stack is in the high-power auxiliary cycle. If yes, close the first valve, control the opening of the second valve and proceed to the next step. If not, proceed to step S2.

[0017] S5. Determine if the fuel cell system is powered off. If not, return to step S2. If yes, proceed to the next step.

[0018] S6, End.

[0019] Based on the above technical solution, the first valve and the second valve can be opened or closed simultaneously.

[0020] Based on the above technical solution, in step S3, the opening degree of the first valve is coupled and controlled according to the amount of hydrogen circulation required for the power of the fuel cell stack.

[0021] Based on the above technical solution, in step S4, the opening degree of the second valve is coupled and controlled according to the amount of hydrogen circulation required for the power of the fuel cell stack.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] (1) Compared with the prior art, the hydrogen auxiliary circulation system of the fuel cell in this invention utilizes the surplus adjustment capacity of the air path, and makes full use of the operating characteristics of the air path of the fuel cell system under low power and high power conditions without adding additional structures and equipment. The hydrogen auxiliary circulation is completed by using air pressure energy through the turbine structure, and the working characteristics of the air path of the fuel cell system are rationally utilized.

[0024] (2) A control method for a fuel cell hydrogen auxiliary circulation system in this invention switches the control of auxiliary circulation power according to high and low operating conditions. Under different states of the fuel cell system, namely high and low power operating conditions, the pressure energy is reused by utilizing the characteristics of air pressure. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a fuel cell hydrogen auxiliary circulation system according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the turbine device in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of a control method for a fuel cell hydrogen auxiliary circulation system according to an embodiment of the present invention.

[0028] In the diagram: 1-hydrogen storage cylinder, 2-pressure reducing valve, 3-proportional valve, 4-turbine unit, 41-drive turbine, 42-driven turbine, 5-air compressor, 61-first valve, 62-second valve, 63-third valve, 7-first gas-liquid separator, 8-second gas-liquid separator, 9-fuel stack, 10-air pressure relief valve, 11-check valve. Detailed Implementation

[0029] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0031] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0032] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] See Figure 1 The schematic diagram shown in this embodiment of the invention illustrates a hydrogen auxiliary circulation system for a fuel cell, comprising a hydrogen storage tank 1, a pressure reducing valve 2, and a proportional valve 3 connected in sequence. The proportional valve 3 is connected to the fuel cell stack 9 via a pipeline and controls the hydrogen entering the stack. The air inlet of the fuel cell stack 9 is connected to an air compressor 5, which is connected to a first valve 61 and the fuel cell stack 9. The air outlet pipeline is connected in sequence to a second valve 62, a first gas-water separator 7, and then discharged into the atmosphere via a turbine unit 4. The hydrogen outlet pipeline is connected to a second gas-water separator 8 and then enters the fuel cell stack 9 via the turbine unit 4. The first valve 61 is connected to the turbine unit 4 via a pipeline, and the second gas-water separator 8 is connected to a third valve 63.

[0034] See Figure 2 The diagram shows the structure of the turbine unit 4 in this embodiment of the invention. The turbine unit 4 includes a driving turbine 41 and a driven turbine 42. The driving turbine 41 is connected to the air path tailpipe, and a first valve 61 is connected to the air path tailpipe through a pipeline. The first valve 61 controls the opening and closing of the air flow in the outlet branch of the air compressor 5. The driven turbine 42 is connected to the hydrogen circulation loop. The driving turbine 41 is rotated by the air from the air path, which in turn drives the driven turbine 42 to rotate. The pulling action generated by the rotation of the driven turbine 42 drives the hydrogen in the hydrogen circulation loop to complete the circulation flow. In this embodiment, the turbine unit 4 is designed with a corresponding shape and size according to the selected fuel cell stack model and the hydrogen-air pipeline.

[0035] Pressure reducing valve 2 is a gas pressure reducing valve, and proportional valve 3 is a solenoid proportional valve.

[0036] The first gas-water separator 7 and the second gas-water separator 8 are one or a combination of two of the following: tubular separator, louvered separator, and cyclone separator. The first gas-water separator 7 separates and collects the generated water in the air path, and the second gas-water separator 8 separates and collects the water in the hydrogen circulation loop.

[0037] Air compressor 5 is either a centrifugal air compressor or a screw air compressor. Since the fuel cell stack has a large margin of adjustable power for air compressor 5 during low-power or start-up phases, a portion of this power can be diverted to turbine unit 4 to drive the active turbine 41 and assist in hydrogen circulation. However, when the fuel cell stack is operating at high power, air compressor 5 often reaches very high operating power. At this time, there is no surplus air pressure at the outlet of air compressor 5 to adjust, but the air flow in the exhaust is very large. If it is simply discharged into the air, the residual pressure energy in the exhaust is wasted. Therefore, through switching valves and pipeline control, the high-power exhaust air is introduced into turbine unit 4 to drive the active turbine 41 and assist in hydrogen circulation, thus achieving multiple utilizations of energy and structure in the fuel cell system.

[0038] The first valve 61, the second valve 62, and the third valve 63 are pneumatic switching valves, electric switching valves, or a combination of pneumatic and electric switching valves, and the third valve 63 controls the amount of liquid water stored in the second gas-water separator 8, or the second valve 62 and the third valve 63 are throttle valves.

[0039] The circulating hydrogen passes through the driven turbine 42 and then through the one-way valve 11 into the reactor hydrogen inlet pipeline. The outflow air is also provided with a tailpipe pipeline, which is equipped with an air pressure relief valve 10. The air pressure relief valve 10 and the second valve 62 work together to control the outflow air discharge, so as to achieve precise control of the power of the turbine unit 4.

[0040] Compared with the prior art, the hydrogen auxiliary circulation system of the fuel cell in this invention utilizes the surplus adjustment capacity of the air path, and makes full use of the operating characteristics of the fuel cell system air path under low power and high power conditions without adding additional structures and equipment. The hydrogen auxiliary circulation is completed by using air pressure energy through the turbine structure, thus making reasonable use of the working characteristics of the fuel cell system air path.

[0041] See Figure 3 The diagram shown is a principle block diagram of a fuel cell hydrogen auxiliary circulation system control method according to an embodiment of the present invention. The control method for a fuel cell hydrogen auxiliary circulation system and its control method includes the following steps:

[0042] S1. The fuel cell stack starts up, and the auxiliary circulation system begins to work;

[0043] S2. Determine whether the current power of the fuel cell stack is in the auxiliary cycle control segment according to the set operating conditions. If yes, determine whether the current power of the fuel cell stack is in the initial power segment auxiliary cycle and proceed to the next step S3. If not, control the first valve 61 and the second valve 62 to remain closed and proceed to S4.

[0044] S3. Simultaneously control the opening degree of the first valve 61 and the second valve 62;

[0045] S4. Determine whether the current power of the fuel cell stack is in the high-power auxiliary cycle. If yes, close the first valve 61, control the opening of the second valve 62 and proceed to the next step. If not, proceed to step S2.

[0046] S5. Determine if the fuel cell system is powered off. If not, return to step S2. If yes, proceed to the next step.

[0047] S6, End.

[0048] The first valve 61 and the second valve 62 can be opened or closed simultaneously. In step S3, the opening degree of the first valve 61 is coupled and controlled according to the amount of hydrogen circulation required for the power of the fuel cell stack; in step S4, the opening degree of the second valve 62 is coupled and controlled according to the amount of hydrogen circulation required for the power of the fuel cell stack. Specifically, when the amount of hydrogen circulation required for the current power of the fuel cell stack increases, the opening degree of the first valve 61 or the second valve 62 is gradually increased until the first valve 61 or the second valve 62 reaches full opening. Then, according to the overall operating status of the fuel cell system (demand for hydrogen and air supply, etc.), the operating power of the air compressor 5 is increased, or when the amount of hydrogen circulation required for the power of the fuel cell stack decreases, the operating power of the air compressor 5 is decreased, so as to simultaneously meet the fuel cell stack gas supply demand and the hydrogen auxiliary circulation demand.

[0049] The present invention discloses a control method for a fuel cell hydrogen auxiliary circulation system, which switches the control of auxiliary circulation power according to high and low operating conditions. Under different states of the fuel cell system, namely high and low power operating conditions, the pressure energy is reused by utilizing the characteristics of air pressure.

[0050] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0051] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0052] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A hydrogen assisted circulation system for a fuel cell, characterized by: The system includes a hydrogen storage cylinder (1), a pressure reducing valve (2), and a proportional valve (3) connected in sequence. The proportional valve (3) is connected to the fuel cell stack (9) through a pipeline and controls the hydrogen entering the stack. The air inlet of the fuel cell stack (9) is connected to an air compressor (5). The air compressor (5) is connected to a first valve (61) and the fuel cell stack (9). The air outlet pipeline is connected to a second valve (62) and a first gas-water separator (7) in sequence and is discharged into the atmosphere after passing through a steam turbine unit (4). The hydrogen outlet pipeline is connected to a second gas-water separator (8) and enters the fuel cell stack (9) after passing through a steam turbine unit (4). The first valve (61) is connected to the steam turbine unit (4) through a pipeline, and the second gas-water separator (8) is connected to a third valve (63). The turbine unit (4) is provided with a driving turbine (41) and a driven turbine (42), wherein the driving turbine (41) is connected to the air path tailpipe and the driven turbine (42) is connected to the hydrogen circulation loop; The first valve (61) is connected to the air path tail drain through a pipeline; the first valve (61) is used to control the opening and closing of the air flow of the outlet branch of the air compressor (5).

2. A hydrogen assisted fuel cell recirculation system according to claim 1, wherein: The pressure reducing valve (2) is a gas pressure reducing valve, and the proportional valve (3) is an electromagnetic proportional valve.

3. A hydrogen assisted circulation system for a fuel cell according to claim 1, wherein: The first gas-water separator (7) and the second gas-water separator (8) are one or a combination of two of the following: tubular separator, louvered separator, and cyclone separator.

4. The hydrogen assisted fuel cell recirculation system of claim 1, wherein: The air compressor (5) is a centrifugal air compressor or a screw air compressor.

5. The hydrogen assisted fuel cell recirculation system of claim 1, wherein: The first valve (61), the second valve (62), and the third valve (63) are pneumatic switching valves, electric switching valves, or a combination of pneumatic switching valves and electric switching valves, and the amount of liquid water stored in the second gas-water separator (8) is controlled by the third valve (63), or the second valve (62) and the third valve (63) are throttle valves.

6. The control method of claim 1-5, wherein Includes the following steps: S1. The fuel cell stack starts up, and the auxiliary circulation system begins to work; S2. Determine whether the current power of the fuel cell stack is in the auxiliary cycle control segment according to the set operating conditions. If yes, determine whether the current power of the fuel cell stack is in the initial power segment auxiliary cycle and proceed to the next step S3. If not, control the first valve (61) and the second valve (62) to remain closed and proceed to S4. S3. Simultaneously control the opening degree of the first valve (61) and the second valve (62); S4. Determine whether the current power of the fuel cell stack is in the high power auxiliary cycle. If yes, close the first valve (61), control the opening of the second valve (62) and proceed to the next step. If not, proceed to step S2. S5. Determine if the fuel cell system is powered off. If not, return to step S2. If yes, proceed to the next step. S6, End.

7. The control method of claim 6, wherein: The first valve (61) and the second valve (62) can be opened or closed simultaneously.

8. The control method of claim 6, wherein: In step S3, the opening degree of the first valve (61) is coupled and controlled according to the amount of hydrogen circulation required for the power of the fuel cell stack.

9. The control method of claim 6, wherein: In step S4, the opening degree of the second valve (62) is coupled and controlled according to the amount of hydrogen circulation required for the power of the fuel cell stack.

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