Hydrogen supply system of fuel cell stack and control method

Abstract

The invention discloses a hydrogen supply system of a fuel cell stack and a control method, and through the cooperation of a gas supply branch and an exhaust branch, the system effectively reduces the hydrogen pressure behind a gas supply pressure reducing valve in a gas supply main path. And at the moment, the main path hydrogen only needs to be supplied with hydrogen slowly consumed by the stack, so that the operation time of the fuel cell stack under high-pressure hydrogen is greatly shortened. Although the high-pressure hydrogen is introduced for a short time, the system can still efficiently complete the tasks of hydrogen supply and liquid water discharge. And the working mode obviously reduces the working pressure of the hydrogen inlet continuously borne by the electric pile, so that the safety and durability of the system are improved, and the risks of hydrogen leakage and permeation to the cathode are effectively reduced. And meanwhile, the system greatly reduces the total compression energy consumption required for continuously reducing the pressure of the gas in the high-pressure hydrogen storage bottle to the working pressure, so that the energy utilization efficiency is improved, and the endurance mileage of the whole vehicle or the operation economy of a fixed system is enhanced.

Description

Technical Field

[0001] This invention relates to the technical field of fuel cell stacks, and particularly to a hydrogen supply system and control method for a fuel cell stack. Background Technology

[0002] When setting the hydrogen inlet pressure for a fuel cell stack, a balance must be struck between several objectives: to ensure a sufficient supply of reactants and effective removal of liquid water, a higher pressure needs to be maintained to promote gas diffusion, uniform distribution, and facilitate the removal of liquid water; however, to reduce hydrogen permeation, minimize the energy consumption required to compress hydrogen in the storage tank to the operating pressure, and control the risk of hydrogen leakage as much as possible, a lower inlet pressure is required. Current solutions typically adopt a compromise strategy, setting a fixed target pressure value (e.g., a low level, approximately 50 kPa). While this setting can basically meet the above-mentioned key functional requirements, maintaining this pressure under the condition of limited pressure in the on-board hydrogen storage tank still leads to significant compression energy consumption and cannot completely avoid the resulting leakage and hydrogen permeation risks. Summary of the Invention The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a hydrogen supply system and control method for a fuel cell stack.

[0003] A hydrogen supply system for a fuel cell stack according to a first aspect of an embodiment of the present invention includes: The main gas supply line includes a high-pressure hydrogen source and a gas supply pressure reducing valve connected in sequence. The outlet of the gas supply pressure reducing valve is connected to the hydrogen inlet of the fuel cell stack. The gas supply pressure reducing valve is configured to reduce the pressure of the high-pressure hydrogen from the high-pressure hydrogen source to a first preset pressure and to replenish the consumed hydrogen to the fuel cell stack. The gas supply branch includes a hydrogen storage unit and a gas supply control valve connected in sequence. The inlet of the hydrogen storage unit is connected to the high-pressure hydrogen source. The hydrogen storage unit is configured to receive and store hydrogen from the high-pressure hydrogen source. The outlet of the gas supply control valve is connected to the hydrogen inlet of the fuel cell stack. The gas supply control valve is configured to open cyclically according to a preset cycle and a preset opening time when the real-time hydrogen pressure in the hydrogen storage unit reaches a second preset pressure. The second preset pressure is greater than the first preset pressure. An exhaust branch includes an exhaust control valve connected to the hydrogen outlet of the fuel cell stack, the exhaust control valve being configured to open and close synchronously with the gas supply control valve.

[0004] According to some embodiments of the present invention, the gas supply branch further includes a mass flow controller installed between the hydrogen storage unit and the high-pressure hydrogen source, the mass flow controller being configured to control the hydrogen pressure within the hydrogen storage unit.

[0005] According to some embodiments of the present invention, a main control valve is installed at the outlet of the high-pressure hydrogen source, and the main control valve is connected to the inlet of the mass flow controller and the inlet of the gas supply pressure reducing valve.

[0006] According to some embodiments of the present invention, a three-way valve is connected between the outlet of the main control valve, the inlet of the mass flow controller, and the inlet of the gas supply pressure reducing valve.

[0007] According to some embodiments of the present invention, the gas supply control valve is a gas supply solenoid valve, which is configured to calculate the real-time hydrogen pressure in the hydrogen storage unit based on the opening degree or flow rate of the mass flow controller. When the real-time hydrogen pressure reaches a second preset pressure, the gas supply solenoid valve opens cyclically according to a preset cycle and a preset opening time.

[0008] According to some embodiments of the present invention, the gas supply control valve is a gas supply pressure limiting valve, the opening pressure value of the gas supply pressure limiting valve is set to the second preset gas pressure, and the gas supply pressure limiting valve is configured to automatically open when the real-time hydrogen pressure in the hydrogen storage unit reaches the opening pressure value.

[0009] According to some embodiments of the present invention, the exhaust control valve is an exhaust solenoid valve, and the exhaust solenoid valve and the gas supply control valve are linked by opening and closing signals to achieve synchronous control of their valve actions.

[0010] A control method for hydrogen supply to a fuel cell stack according to a second aspect of the present invention, applicable to the aforementioned hydrogen supply system, the control method comprising: The gas supply pressure reducing valve is controlled to reduce the pressure of high-pressure hydrogen from the high-pressure hydrogen source to a first preset pressure, and to replenish the consumed hydrogen to the fuel cell stack. The hydrogen storage unit is controlled to receive and store hydrogen from the high-pressure hydrogen source; When the real-time hydrogen pressure in the hydrogen storage unit reaches the second preset pressure, the gas supply control valve and the exhaust control valve are controlled to open synchronously in a preset cycle and a preset opening time, wherein the second preset pressure is greater than the first preset pressure.

[0011] According to some embodiments of the present invention, the control method further includes: The real-time hydrogen pressure in the hydrogen storage unit is calculated based on the opening degree or flow rate of the mass flow controller.

[0012] According to some embodiments of the present invention, the control method further includes: setting the opening pressure value of the gas supply pressure limiting valve to the second preset gas pressure, and when the real-time hydrogen pressure in the hydrogen storage unit reaches the opening pressure value, the gas supply pressure limiting valve will automatically open.

[0013] The present invention has at least the following beneficial effects: Under normal conditions, this invention reduces the pressure of hydrogen from a high-pressure hydrogen source to a first preset pressure via a gas supply pressure reducing valve, continuously replenishing the consumed hydrogen in the fuel cell stack. At this time, the gas supply control valve and the exhaust control valve are closed, and the hydrogen storage unit continuously receives and stores hydrogen from the high-pressure hydrogen source. When the real-time hydrogen pressure in the hydrogen storage unit reaches a second preset pressure, the system enters a coordinated operation phase: the gas supply control valve opens cyclically according to a preset cycle and preset opening time, and the exhaust control valve opens and closes synchronously. This linkage mechanism increases the hydrogen flow pressure difference, enabling rapid replenishment of hydrogen and rapid discharge of liquid water within the fuel cell stack.

[0014] This invention, through the coordination of the gas supply branch and the exhaust branch, effectively reduces the hydrogen pressure after the gas pressure reducing valve in the main gas supply line. At this point, the main gas supply line only needs to supply the slowly consumed hydrogen from the fuel cell stack, thus significantly shortening the operating time of the fuel cell stack under high-pressure hydrogen. Despite the short high-pressure hydrogen inlet time, the system can still efficiently complete the tasks of hydrogen supply and liquid water discharge. Furthermore, this operating mode significantly reduces the continuous hydrogen inlet working pressure on the stack, not only improving system safety and durability but also effectively reducing the risk of hydrogen leakage and permeation into the cathode. Simultaneously, the system significantly reduces the total compression energy consumption required to continuously depressurize the gas in the high-pressure hydrogen storage tank to the working pressure, thereby improving energy utilization efficiency and enhancing the driving range of the vehicle or the operating economy of a stationary system.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 This is a schematic diagram of an embodiment of the hydrogen supply system provided by the present invention. Figure 2 This is a flowchart of an embodiment of the control method provided by the present invention; Icon labels: Main gas supply line 100; High-pressure hydrogen source 110; Gas supply pressure reducing valve 120; Main control valve 130; Three-way valve 140; Gas supply branch 200; hydrogen storage unit 210; gas supply control valve 220; mass flow controller 230; Exhaust branch 300; Exhaust control valve 310; 400 fuel cell stack. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0022] The conventional hydrogen supply scheme for a fuel cell stack 400 typically involves directly introducing hydrogen from a high-pressure hydrogen source 110 into the stack after pressure reduction, and using an outlet solenoid valve to perform hydrogen exchange and liquid water discharge. However, this scheme still suffers from the problem of excessively high hydrogen inlet pressure, resulting in higher system compression energy consumption and a higher risk of hydrogen leakage and membrane perforation.

[0023] To more effectively resolve the contradiction between the demands of high-pressure operation and the advantages of low-pressure operation, this invention proposes a hydrogen supply system and control method for a fuel cell stack 400. Its core objective is to significantly reduce the inlet hydrogen pressure while ensuring a continuous and sufficient supply of reactants to meet dynamic power output requirements, thereby achieving energy savings and improved system safety from the source.

[0024] like Figure 1 As shown, the hydrogen supply system of the present invention includes: a main gas supply line 100, a gas supply branch line 200, and an exhaust branch line 300.

[0025] The main gas supply line 100 of the present invention includes a high-pressure hydrogen source 110 and a gas supply pressure reducing valve 120 connected in sequence. The outlet of the gas supply pressure reducing valve 120 is connected to the hydrogen inlet of the fuel cell stack 400. The high-pressure hydrogen source 110 is used to provide high-pressure hydrogen.

[0026] The gas supply pressure reducing valve 120 of the present invention is used to reduce the pressure of high-pressure hydrogen from high-pressure hydrogen source 110 to a first preset pressure and to replenish the consumed hydrogen in fuel cell stack 400. Under normal operation of fuel cell stack 400, the pressure of hydrogen in main gas supply line 100 is reduced by gas supply pressure reducing valve 120. At this time, main gas supply line 100 is only responsible for replenishing the hydrogen in the stack after it is slowly consumed.

[0027] The gas supply branch 200 of the present invention includes a hydrogen storage unit 210 and a gas supply control valve 220 connected in sequence. The inlet of the hydrogen storage unit 210 is connected to the high-pressure hydrogen source 110. The hydrogen storage unit 210 is used to receive and store hydrogen from the high-pressure hydrogen source 110. The outlet of the gas supply control valve 220 is connected to the hydrogen inlet of the fuel cell stack 400. The gas supply control valve 220 is used to cyclically open according to a preset cycle and a preset opening time when the real-time hydrogen pressure in the hydrogen storage unit 210 reaches a second preset pressure.

[0028] In this invention, the second preset gas pressure is greater than the first preset gas pressure. It can be understood that the gas pressure of the gas supply branch 200 is higher than the gas pressure of the main gas supply branch 100. The gas supply branch 200 replenishes hydrogen to the fuel cell stack 400 periodically through preset high-pressure hydrogen, which can quickly replenish hydrogen and quickly discharge liquid water from the fuel cell stack 400.

[0029] The exhaust branch 300 of the present invention includes an exhaust control valve 310 connected to the hydrogen outlet of the fuel cell stack 400, and the exhaust control valve 310 is used to open and close synchronously with the gas supply control valve 220.

[0030] Under normal conditions, this invention reduces the pressure of hydrogen from the high-pressure hydrogen source 110 to a first preset pressure via the gas supply pressure reducing valve 120, continuously replenishing the consumed hydrogen for the fuel cell stack 400. At this time, the gas supply control valve 220 and the exhaust control valve 310 are closed, while the hydrogen storage unit 210 continuously receives and stores hydrogen from the high-pressure hydrogen source 110. When the real-time hydrogen pressure in the hydrogen storage unit 210 reaches a second preset pressure, the system enters a coordinated operation phase: the gas supply control valve 220 opens cyclically according to a preset cycle and preset opening time, and the exhaust control valve 310 opens and closes synchronously. This linkage mechanism increases the hydrogen flow pressure difference, enabling rapid replenishment of hydrogen and rapid discharge of liquid water within the fuel cell stack 400.

[0031] Furthermore, the gas supply branch 200 in this embodiment also includes a mass flow controller 230 installed between the hydrogen storage unit 210 and the high-pressure hydrogen source 110. The mass flow controller 230 is used to control the hydrogen pressure in the hydrogen storage unit 210. The mass flow controller 230 can be mechanical or electronic, and it has a small opening, so that the pressure in the subsequent hydrogen storage unit 210 rises slowly.

[0032] In this embodiment, a main control valve 130 is installed at the outlet of the high-pressure hydrogen source 110. The main control valve 130 is connected to the inlet of the mass flow controller 230 and the inlet of the gas supply pressure reducing valve 120. The main control valve 130 is used to control the supply of high-pressure hydrogen source 110. When the fuel cell stack 400 is not running or the system leaks, the main control valve 130 is closed.

[0033] Furthermore, in this embodiment, a three-way valve 140 is connected between the outlet of the main control valve 130, the inlet of the mass flow controller 230, and the inlet of the gas supply pressure reducing valve 120. The three-way valve 140 controls the opening and closing of the main gas supply line 100 and the gas supply branch line 200 separately.

[0034] The gas supply control valve 220 has two structural forms: the first is that the gas supply control valve 220 adopts a gas supply solenoid valve, and the second is that the gas supply control valve 220 adopts a gas supply pressure limiting valve.

[0035] When the gas supply control valve 220 is a gas supply solenoid valve, the gas supply solenoid valve is configured to calculate the real-time hydrogen pressure in the hydrogen storage unit 210 based on the opening degree or flow rate of the mass flow controller 230. When the real-time hydrogen pressure reaches the second preset pressure, the gas supply solenoid valve will open cyclically according to the preset cycle and preset opening time.

[0036] When the gas supply control valve 220 is a gas supply pressure limiting valve, the opening pressure value of the gas supply pressure limiting valve is set to the second preset gas pressure. The gas supply pressure limiting valve is used to automatically open when the real-time hydrogen pressure in the hydrogen storage unit 210 reaches the opening pressure value.

[0037] In this embodiment of the invention, the exhaust control valve 310 is an exhaust solenoid valve. The exhaust solenoid valve and the air supply control valve 220 are linked by opening and closing signals to achieve synchronous control of their valve actions.

[0038] This invention also proposes a control method for hydrogen supply in a fuel cell stack 400, applicable to the aforementioned hydrogen supply system, such as... Figure 2 As shown, the control methods include: Step S100: Control the gas supply pressure reducing valve 120 to reduce the pressure of high-pressure hydrogen from high-pressure hydrogen source 110 to the first preset pressure, and replenish the consumed hydrogen to fuel cell stack 400. Step S200: Control the hydrogen storage unit 210 to receive and store hydrogen from the high-pressure hydrogen source 110; Step S300: When the real-time hydrogen pressure in the hydrogen storage unit 210 reaches the second preset pressure, control the gas supply control valve 220 and the exhaust control valve 310 to open synchronously in a preset cycle and preset opening time, wherein the second preset pressure is greater than the first preset pressure.

[0039] To obtain the real-time hydrogen pressure in the hydrogen storage unit 210, if the gas supply control valve 220 is a gas supply solenoid valve, the real-time hydrogen pressure in the hydrogen storage unit 210 can be calculated based on the opening degree or flow rate of the mass flow controller 230.

[0040] If the gas supply control valve 220 adopts a gas supply pressure limiting valve, the present invention sets the opening pressure value of the gas supply pressure limiting valve to the second preset gas pressure. When the real-time hydrogen pressure in the hydrogen storage unit 210 reaches the opening pressure value, the gas supply pressure limiting valve will open automatically.

[0041] The present invention provides an example implementation of the control method described above: The high-pressure hydrogen source 110 in this invention has a pressure of 35 MPa. After passing through the gas supply pressure reducing valve 120, the hydrogen is reduced to 20 kPa and then flows through the fuel cell stack 400 to replenish the hydrogen consumption. The hydrogen from the gas supply branch 200, after passing through the mass flow controller 230, slowly increases the hydrogen pressure in the hydrogen storage unit 210. After a certain period of calculation, when the preset pressure value of 50 kPa is reached, the gas supply control valve 220 of the gas supply branch 200 and the exhaust control valve 310 after the fuel cell stack 400 open simultaneously for 0.5 seconds to quickly replenish the hydrogen and purge the liquid water.

[0042] This invention, through the coordination of the gas supply branch 200 and the exhaust branch 300, effectively reduces the hydrogen pressure after the gas supply pressure reducing valve 120 in the main gas supply line 100. At this time, the main gas supply line only needs to supply the slowly consumed hydrogen from the fuel cell stack, thus significantly shortening the operating time of the fuel cell stack 400 under high-pressure hydrogen. Despite the short high-pressure hydrogen inlet time, the system can still efficiently complete the tasks of hydrogen supply and liquid water discharge. Furthermore, this operating mode significantly reduces the continuous hydrogen inlet working pressure on the stack, not only improving system safety and durability but also effectively reducing the risk of hydrogen leakage and permeation into the cathode. Simultaneously, the system significantly reduces the total compression energy consumption required to continuously depressurize the gas in the high-pressure hydrogen storage tank to the working pressure, thereby improving energy utilization efficiency and enhancing the driving range of the vehicle or the operating economy of a stationary system.

[0043] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0044] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A hydrogen supply system for a fuel cell stack, characterized in that, include: The main gas supply line (100) includes a high-pressure hydrogen source (110) and a gas supply pressure reducing valve (120) connected in sequence. The outlet of the gas supply pressure reducing valve (120) is connected to the hydrogen inlet of the fuel cell stack (400). The gas supply pressure reducing valve (120) is configured to reduce the pressure of the high-pressure hydrogen from the high-pressure hydrogen source (110) to a first preset pressure and to replenish the consumed hydrogen for the fuel cell stack (400). The gas supply branch (200) includes a hydrogen storage unit (210) and a gas supply control valve (220) connected in sequence. The inlet of the hydrogen storage unit (210) is connected to the high-pressure hydrogen source (110). The hydrogen storage unit (210) is configured to receive and store hydrogen from the high-pressure hydrogen source (110). The outlet of the gas supply control valve (220) is connected to the hydrogen inlet of the fuel cell stack (400). The gas supply control valve (220) is configured to open cyclically according to a preset cycle and a preset opening time when the real-time hydrogen pressure in the hydrogen storage unit (210) reaches a second preset pressure. The second preset pressure is greater than the first preset pressure. The exhaust branch (300) includes an exhaust control valve (310) connected to the hydrogen outlet of the fuel cell stack (400), the exhaust control valve (310) being configured to open and close synchronously with the gas supply control valve (220).

2. The hydrogen supply system according to claim 1, characterized in that: The gas supply branch (200) also includes a mass flow controller (230) installed between the hydrogen storage unit (210) and the high-pressure hydrogen source (110), the mass flow controller (230) being configured to control the hydrogen pressure in the hydrogen storage unit (210).

3. The hydrogen supply system according to claim 2, characterized in that: The outlet of the high-pressure hydrogen source (110) is equipped with a main control valve (130), which is connected to the inlet of the mass flow controller (230) and the inlet of the gas supply pressure reducing valve (120).

4. The hydrogen supply system according to claim 3, characterized in that: A three-way valve (140) is connected between the outlet of the main control valve (130), the inlet of the mass flow controller (230), and the inlet of the gas supply pressure reducing valve (120).

5. The hydrogen supply system according to claim 2, characterized in that: The gas supply control valve (220) is a gas supply solenoid valve. The gas supply solenoid valve is configured to calculate the real-time hydrogen pressure in the hydrogen storage unit (210) based on the opening degree or flow rate of the mass flow controller (230). When the real-time hydrogen pressure reaches the second preset pressure, the gas supply solenoid valve will open cyclically according to the preset cycle and preset opening time.

6. The hydrogen supply system according to claim 1, characterized in that: The gas supply control valve (220) is a gas supply pressure limiting valve. The opening pressure value of the gas supply pressure limiting valve is set to the second preset gas pressure. The gas supply pressure limiting valve is configured to automatically open when the real-time hydrogen pressure in the hydrogen storage unit (210) reaches the opening pressure value.

7. The hydrogen supply system according to claim 1, characterized in that: The exhaust control valve (310) is an exhaust solenoid valve. The exhaust solenoid valve and the gas supply control valve (220) are linked by opening and closing signals to achieve synchronous control of their valve actions.

8. A method for controlling hydrogen supply to a fuel cell stack, characterized in that, The control method, applicable to any one of claims 1 to 7, comprises: The gas supply pressure reducing valve (120) is controlled to reduce the pressure of high-pressure hydrogen from the high-pressure hydrogen source (110) to a first preset pressure, and to replenish the consumed hydrogen to the fuel cell stack (400); The hydrogen storage unit (210) is controlled to receive and store hydrogen from the high-pressure hydrogen source (110); When the real-time hydrogen pressure in the hydrogen storage unit (210) reaches the second preset pressure, the gas supply control valve (220) and the exhaust control valve (310) are controlled to open synchronously in a preset cycle and a preset opening time, wherein the second preset pressure is greater than the first preset pressure.

9. The control method according to claim 8, characterized in that: in, A mass flow controller (230) is provided between the hydrogen storage unit (210) and the high-pressure hydrogen source (110). The control method: The real-time hydrogen pressure in the hydrogen storage unit (210) is calculated based on the opening degree or flow rate of the mass flow controller (230).

10. The control method according to claim 8, characterized in that: The gas supply control valve (220) is a gas supply pressure limiting valve; The control method: The opening pressure value of the gas supply pressure limiting valve is set to the second preset gas pressure. When the real-time hydrogen pressure in the hydrogen storage unit (210) reaches the opening pressure value, the gas supply pressure limiting valve will automatically open.

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