Fuel cell hydrogen circulation system and control method thereof

Abstract

The fuel cell hydrogen circulation system comprises an electric pile, a hydrogen supply device, an FCU module, a first circulation loop, a second circulation loop and a hydrogen supply main pipeline, incompletely reacted hydrogen in the galvanic pile can flow back to the galvanic pile again through the first circulation loop or the second circulation loop for full reaction; a three-way valve and an ejector are sequentially arranged on the first circulation loop in the hydrogen circulation direction; a three-way valve and a hydrogen circulating pump are sequentially arranged on the second circulating loop in the hydrogen circulating direction; the hydrogen supply pipeline comprises a hydrogen bottle, a stop valve, a new hydrogen heater, a proportional valve, a pressure transmitter, an ejector and a pressure sensor; the pressure sensor is used for detecting an air inlet pressure value of the electric pile; the proportional valve is used for adjusting the hydrogen inlet pressure in the hydrogen supply pipeline. According to the invention, the problem that the pressure and flow accuracy of gas entering the fuel cell are reduced due to the difference of dynamic response and control accuracy caused by various factors of the conventional proportional valve is solved, and meanwhile, the utilization efficiency of hydrogen fuel is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cells, and in particular to a fuel cell hydrogen circulation system and a control method thereof. Background Art

[0002] Currently, the main solution for hydrogen fuel cells on the market is that the hydrogen supply module and the hydrogen circulation pump are two products that provide hydrogen supply and hydrogen circulation for the fuel cell. A single hydrogen circulation pump consumes a lot of power in a high-power fuel cell, and has the disadvantages of large size, heavy weight, and high noise. A single ejector is difficult to meet the hydrogen circulation needs of each power range.

[0003] As an important component in the gas pressure control of the fuel cell hydrogen system, the proportional valve controls the hydrogen pressure and flow rate entering the fuel cell to ensure the stable operation of the fuel cell. However, due to factors such as poor production consistency, aging of the internal structure, different operating temperatures, and differences in the opening and closing processes, the dynamic response and control accuracy of the electronically controlled proportional valve vary, which will lead to a decrease in the accuracy of controlling the gas pressure and flow rate entering the fuel cell, thereby affecting the normal use of the fuel cell. Summary of the invention

[0004] The object of the present invention is to provide a fuel cell hydrogen circulation system and a control method thereof.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions: a fuel cell hydrogen circulation system, including a fuel cell stack, a hydrogen supply device, an FCU module, a first circulation loop, a second circulation loop, and a hydrogen supply main line; the hydrogen supply device stores hydrogen and provides hydrogen to the fuel cell stack to carry out fuel chemical reactions in the fuel cell stack; hydrogen that has not completely reacted in the fuel cell stack can flow back to the fuel cell stack through the first circulation loop or the second circulation loop for full reaction; the first circulation loop is sequentially provided with a three-way valve and an ejector along the hydrogen flow direction; the second circulation loop is sequentially provided with a three-way valve and a hydrogen circulation pump along the hydrogen flow direction; the hydrogen supply pipeline includes a hydrogen bottle, a stop valve, a new hydrogen heater, a proportional valve, a pressure transmitter, an ejector and a pressure sensor; the pressure sensor is used to detect the intake pressure value of the fuel cell stack; the proportional valve is used to adjust the hydrogen intake pressure in the hydrogen supply pipeline.

[0006] Furthermore, the first circulation loop and the second circulation loop are arranged in parallel and are both connected to the fuel cell stack.

[0007] Furthermore, both ends of the first circulation loop and both ends of the second circulation loop are respectively connected to the inlet and outlet of the fuel cell stack.

[0008] Furthermore, the ejector includes an ejector inlet, an ejector outlet and an ejector port.

[0009] Furthermore, the ejector inlet is connected to the outlet of the hydrogen supply device through the hydrogen supply main line; the ejector outlet is connected to the inlet of the fuel cell stack.

[0010] Furthermore, the fuel cell hydrogen circulation system also includes a power supply for supplying power to various electrical components of the fuel cell hydrogen circulation system.

[0011] Compared with the prior art, the beneficial effects of the fuel cell hydrogen circulation system of the present invention are: it solves the problem that the dynamic response and control accuracy of the proportional valve are different due to various factors, resulting in a decrease in the accuracy of the gas pressure and flow entering the fuel cell, and at the same time effectively improves the utilization efficiency of hydrogen fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention.

[0013] Figure 2 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0014] See also Figure 1 A fuel cell hydrogen circulation system includes a fuel cell stack 40, a hydrogen supply device 50, an FCU module, a first circulation loop 10, a second circulation loop 20, and a hydrogen supply main line 30.

[0015] The hydrogen supply device 50 stores hydrogen and provides hydrogen to the fuel cell stack 40 to perform a fuel chemical reaction in the fuel cell stack 40. The hydrogen that is not completely reacted in the fuel cell stack 40 can flow back to the fuel cell stack 40 through the first circulation loop 10 or the second circulation loop 20 to fully react.

[0016] The first circulation loop 10 and the second circulation loop 20 are arranged in parallel and are both connected to the stack 40. Both ends of the first circulation loop 10 and both ends of the second circulation loop 20 are connected to the inlet and outlet of the stack 40 respectively.

[0017] The first circulation loop 10 is provided with a three-way valve 12 and an ejector 34 in sequence along the hydrogen flow direction. The second circulation loop 20 is provided with a three-way valve 12 and a hydrogen circulation pump 22 in sequence along the hydrogen flow direction.

[0018] The ejector 34 includes an ejector inlet, an ejector outlet, and an ejector port. The ejector inlet is connected to the outlet of the hydrogen supply device 50 through the hydrogen supply main line 30. The ejector outlet is connected to the inlet of the fuel cell stack 40.

[0019] The hydrogen supply pipeline 30 includes a hydrogen bottle 50 , a stop valve 35 , a new hydrogen heater 31 , a proportional valve 32 , a pressure transmitter 33 , an ejector 34 and a pressure sensor 36 .

[0020] The fuel cell hydrogen circulation system also includes a water separator 60. The inlet of the water separator 60 is connected to the outlet of the fuel cell stack 40, and the outlet of the water separator 60 is connected to the three-way valve 12. The hydrogen-containing mixed gas after the reaction of the fuel cell stack 40 has a high water vapor content, and water vapor separation is performed in the water separator 60. Among them, the hydrogen used for secondary circulation is discharged through the outlet of the water separator 60 and enters the first circulation loop 10 or the second circulation loop 20 for reuse.

[0021] A pressure sensor 36 is provided at the inlet of the fuel cell stack 40, and a proportional valve 32 and a pressure transmitter 33 are provided on the hydrogen supply pipeline 30. The pressure sensor 36 is used to detect the intake pressure value of the fuel cell stack 40. The proportional valve 32 is used to adjust the hydrogen intake pressure in the hydrogen supply pipeline 30. The FCU module obtains the intake pressure value collected by the pressure sensor 36, and compares the intake pressure value with the target intake pressure value. By controlling the opening of the proportional valve 32, the intake pressure value is adjusted to the target value, thereby strengthening the internal safety monitoring of the fuel cell hydrogen circulation system.

[0022] The fuel cell hydrogen circulation system also includes a power source for supplying power to various electrical components of the fuel cell hydrogen circulation system.

[0023] See also Figure 2 , a control method for a fuel cell hydrogen circulation system comprises the following steps:

[0024] Obtaining the operating status of the battery stack 40;

[0025] When the fuel cell stack 40 is running at low power, the hydrogen circulation pump 22 supplies hydrogen to the fuel cell stack 40 through the second circulation loop 20; the hydrogen supply device 50 supplies hydrogen to the fuel cell stack 40 through the ejector 34 at the same time;

[0026] When the fuel cell stack 40 operates at high power, the ejector 34 supplies hydrogen to the fuel cell stack 40 through the first circulation loop 10 ; the hydrogen supply device 50 simultaneously supplies hydrogen to the fuel cell stack 40 through the ejector 34 .

[0027] The operating status of the fuel cell stack 40 is acquired by the FCU module, mainly referring to the operating power of the fuel cell stack 40. During the operation of the fuel cell stack 40, the operating power can be adjusted by adjusting the hydrogen inlet pressure, hydrogen inlet flow, temperature management, etc.

[0028] Advantages of the present invention:

[0029] 1. The ability of hydrogen injection is increased on the basis of hydrogen supply. Considering that the single-pole ejector covers fewer operating points and cannot meet the full operating condition coverage, this solution adopts a hydrogen supply system with a single ejector in parallel with a hydrogen circulation pump, which can meet the hydrogen supply and circulation needs of high-power fuel cells, and has the advantages of flexible control, low power consumption and low noise.

[0030] 2. A three-way valve is used to control the switching of the ejector and the hydrogen circulation pump. At a small operating point, the three-way valve is connected to the hydrogen circulation pump to provide hydrogen supply for the fuel cell. At a large operating point, the three-way valve is connected to the ejector to provide hydrogen supply for the fuel cell.

[0031] 3. It is equipped with an integrated gas-water separator, which can separate the remaining hydrogen in the fuel cell from gas and water to prevent the fuel cell from being flooded by excessive liquid water.

[0032] 4. It is equipped with a new hydrogen heater that can heat the reacting hydrogen in the fuel cell to ensure that it is at the optimal operating temperature, the reaction rate of hydrogen and oxygen is fast, and the energy conversion efficiency is maximized.

[0033] 5. The ejector and the hydrogen circulation pump are connected in parallel. The excess unreacted hydrogen in the fuel cell system is recycled and reused. At the same time, the wet hydrogen refluxed by the ejector and the hydrogen circulation pump is mixed with the dry hydrogen passing through the proportional valve to adjust the humidity of the hydrogen humidification entering the reactor stack.

[0034] 6. A pressure transmitter is provided at the outlet of the proportional valve. The pressure transmitter is used to detect the outlet pressure of the proportional valve and send the signal to the controller. The controller compares the received signal with the proportional valve set pressure signal to control the opening ratio of the proportional valve, so that the outlet pressure signal of the proportional valve is consistent with the set pressure signal. The closed-loop control of the outlet pressure of the proportional valve is realized to ensure the stable operation of the fuel cell.

[0035] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0036] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A fuel cell hydrogen circulation system, characterized in that: It includes a fuel cell stack, a hydrogen supply device, an FCU module, a first circulation loop, a second circulation loop, and a hydrogen supply main line; the hydrogen supply device stores hydrogen and provides hydrogen to the fuel cell stack to carry out fuel chemical reactions in the fuel cell stack; hydrogen that has not completely reacted in the fuel cell stack can flow back to the fuel cell stack through the first circulation loop or the second circulation loop for full reaction; the first circulation loop is sequentially provided with a three-way valve and an ejector along the hydrogen flow direction; the second circulation loop is sequentially provided with a three-way valve and a hydrogen circulation pump along the hydrogen flow direction; the hydrogen supply pipeline includes a hydrogen bottle, a stop valve, a new hydrogen heater, a proportional valve, a pressure transmitter, an ejector and a pressure sensor; the pressure sensor is used to detect the intake pressure value of the fuel cell stack; the proportional valve is used to adjust the hydrogen intake pressure in the hydrogen supply pipeline.

2. The fuel cell hydrogen circulation system according to claim 1, characterized in that: The first circulation loop and the second circulation loop are arranged in parallel and are both connected to the battery stack.

3. The fuel cell hydrogen circulation system according to claim 1, characterized in that: Both ends of the first circulation loop and both ends of the second circulation loop are connected to the inlet and outlet of the fuel cell stack respectively.

4. The fuel cell hydrogen circulation system according to claim 1, characterized in that: The ejector comprises an ejector inlet, an ejector outlet and an ejector port.

5. The fuel cell hydrogen circulation system according to claim 4, characterized in that: The ejector inlet is connected to the outlet of the hydrogen supply device through the hydrogen supply main line; the ejector outlet is connected to the inlet of the fuel cell stack.

6. The fuel cell hydrogen circulation system according to claim 5, characterized in that: The fuel cell hydrogen circulation system also includes a power source for supplying power to various electrical components of the fuel cell hydrogen circulation system.

7. The control method of the fuel cell hydrogen circulation system according to claim 1, characterized in that: The following steps are involved: Obtain the operating status of the battery stack; When the fuel cell stack is running at low power, the hydrogen circulation pump supplies hydrogen to the fuel cell stack through the second circulation loop; the hydrogen supply device also supplies hydrogen to the fuel cell stack through the ejector; When the fuel cell stack is running at high power, the ejector supplies hydrogen to the fuel cell stack through the first circulation loop; the hydrogen supply device also supplies hydrogen to the fuel cell stack through the ejector.

8. The control method of the fuel cell hydrogen circulation system according to claim 7, characterized in that: The operating status of the fuel cell stack is obtained by the FCU module, which mainly refers to the operating power of the fuel cell stack. During the operation of the fuel cell stack, the operating power can be adjusted by adjusting the hydrogen inlet pressure, hydrogen inlet flow, temperature management, etc.

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