Anode gas circuit for fuel cell stack and fuel cell system

Abstract

The utility model relates to an anode gas loop for a fuel cell stack. The anode gas loop comprises a hydrogen supply device; the gas supply pipeline is connected between the hydrogen supply device and the anode inlet of the fuel cell stack; the ejector is arranged in the gas supply pipeline and is provided with a first ejection inlet, a second ejection inlet and an ejection outlet, the first ejection inlet is connected to the hydrogen supply device, and the ejection outlet is connected to the anode inlet; the exhaust pipeline is connected to the anode outlet of the fuel cell stack and is provided with a first exhaust branch and a second exhaust branch, the first exhaust branch is connected to the second injection inlet of the injector, and the second exhaust branch is connected to the gas supply pipeline at the downstream of the injection outlet; the hydrogen circulating pump is arranged in the second exhaust branch; and the switching assembly is used for implementing switching between a series connection mode and a parallel connection mode of the hydrogen circulating pump and the ejector. The utility model also relates to a fuel cell system. The hydrogen circulation effect can be optimized, and the working performance of the fuel cell system can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cells, in particular to an anode gas loop for a fuel cell stack, and also to a corresponding fuel cell system. Background Art

[0002] In recent years, with the development of society and the progress of science and technology, people are paying more and more attention to the problems of air pollution and energy loss. A fuel cell is a highly efficient power generation device that converts the chemical energy in fuel and oxidant into electrical energy directly by electrochemical reaction without going through the combustion process. Since the reaction product is mainly water and basically no harmful gas is emitted, fuel cells have significant advantages of being clean and environmentally friendly and can be used advantageously in the field of vehicles in particular.

[0003] In a fuel cell system, in order to make the reaction inside the fuel cell stack sufficient and improve the output performance, an excess amount of hydrogen is usually supplied to the fuel cell stack, and the hydrogen cannot be completely consumed, and the unconsumed hydrogen is discharged from the anode outlet of the fuel cell stack. In order to improve the utilization rate of hydrogen, the discharged hydrogen needs to be circulated to the anode inlet again. Since the exhaust pressure is significantly less than the supply pressure, an additional driving device is required to achieve hydrogen recycling, and the driving device is usually an ejector or a hydrogen circulation pump, wherein the ejector has the advantages of simple structure, low cost, high reliability and no parasitic power, but the ejector is difficult to cover the requirements of the fuel cell system in a wide power range and has a poor ejection effect especially under low power load conditions, and the hydrogen circulation pump adjusts the speed to adapt to the power range of the fuel cell under different working conditions, but has the disadvantages of large size, high noise and large parasitic power. Utility Model Content

[0004] Therefore, the purpose of the utility model is to propose an improved anode gas circuit for a fuel cell stack, which can comprehensively utilize the advantages of a hydrogen circulation pump and an ejector, and flexibly optimize the hydrogen circulation effect according to different working conditions, thereby improving the working performance of the fuel cell system.

[0005] According to a first aspect of the present utility model, an anode gas loop for a fuel cell stack is provided, wherein the anode gas loop comprises at least:

[0006] -Hydrogen supply device;

[0007] - a gas supply pipeline, the gas supply pipeline being configured to be connected between the hydrogen supply device and the anode inlet of the fuel cell stack;

[0008] - an ejector arranged in the gas supply pipeline, the ejector having a first ejection inlet, a second ejection inlet and an ejection outlet, wherein the first ejection inlet is connected to the hydrogen supply device, and the ejection outlet is connected to the anode inlet;

[0009] - an exhaust pipeline, the exhaust pipeline being configured to be connected to an anode outlet of the fuel cell stack, wherein the exhaust pipeline has a first exhaust branch and a second exhaust branch, the first exhaust branch being connected to the second ejection inlet of the ejector, and the second exhaust branch being connected to the gas supply pipeline downstream of the ejection outlet;

[0010] - a hydrogen circulation pump, which is arranged in the second exhaust branch; and

[0011] - a switching assembly configured and adapted to implement switching between a series connection mode and a parallel connection mode of the hydrogen circulation pump and the ejector.

[0012] Compared with the prior art, in the anode gas loop according to the utility model, an ejector is arranged in the gas supply pipeline, the first ejector inlet of the ejector is connected to the gas supply device for supplying high-pressure hydrogen, the second ejector inlet is connected to the first exhaust branch of the exhaust pipeline, and a hydrogen circulation pump is arranged in the second exhaust branch of the exhaust pipeline, and the switching between the series connection mode and the parallel connection mode of the hydrogen circulation pump and the ejector is realized by the switching component, which can realize the simultaneous operation of the hydrogen circulation pump and the ejector to fully utilize the advantages of the hydrogen circulation pump and the ejector, wherein in the series connection mode, the hydrogen circulation pump and the ejector successively pump the same flow of hydrogen, so that the hydrogen circulation pump and the ejector respectively bear different shares of the pressure rise, thereby achieving a significantly greater pressure rise as a whole, and in the parallel connection mode, the hydrogen circulation pump and the ejector pump different shares of hydrogen flow at the same pumping pressure, thereby achieving a significantly increased hydrogen flow as a whole. This can flexibly use the corresponding connection mode for different working conditions to optimize the hydrogen circulation effect, thereby improving the working performance of the fuel cell system.

[0013] According to an exemplary embodiment of the utility model, the switching component has at least a first switch valve arranged in the first exhaust branch, a second switch valve arranged in the second exhaust branch, and a third switch valve arranged in a bypass branch between the first exhaust branch and the second exhaust branch, and a circulation pump outlet of the hydrogen circulation pump is connected to the first exhaust branch through the bypass branch, wherein, in the series connection mode, the first switch valve and the second switch valve are turned off and the third switch valve is turned on, and in the parallel connection mode, the first switch valve and the second switch valve are turned on and the third switch valve is turned off.

[0014] According to an exemplary embodiment of the present invention, the switching assembly additionally has a three-way valve arranged between the first exhaust branch and the second exhaust branch.

[0015] According to an exemplary embodiment of the present utility model, the three-way valve is integrally constructed with the first switch valve; and / or the opening degree of the three-way valve is adjusted according to the operating power of the fuel cell stack.

[0016] According to an exemplary embodiment of the present utility model, the switching component is configured to switch to the series connection mode when the operating power of the fuel cell stack is less than a preset power, and to switch to the parallel connection mode when the operating power of the fuel cell stack is greater than or equal to the preset power.

[0017] According to an exemplary embodiment of the present invention, the exhaust line has a third exhaust branch, which leads to the external environment, wherein a fourth switching valve is arranged in the third exhaust branch.

[0018] According to an exemplary embodiment of the present utility model, the anode gas circuit includes a gas-liquid separator, and the gas-liquid separator is arranged upstream of the first exhaust branch and the second exhaust branch in the exhaust pipeline.

[0019] According to an exemplary embodiment of the present utility model, the anode gas loop includes a proportional valve and / or a hydrogen injector to adjust the pressure and flow rate of the hydrogen gas flowing from the hydrogen supply device into the gas supply pipeline.

[0020] According to an exemplary embodiment of the present utility model, the hydrogen supply device is configured as a high-pressure hydrogen storage tank; and / or the ejector is configured in the form of a venturi tube.

[0021] According to a second aspect of the present utility model, a fuel cell system is provided, wherein the fuel cell system at least comprises:

[0022] -Fuel cell stack;

[0023] - an anode gas circuit according to the invention; and

[0024] - a cathode gas circuit connected between a cathode inlet and a cathode outlet of the fuel cell stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present invention can be better understood. The accompanying drawings include:

[0026] Figure 1A schematic block diagram of a fuel cell system according to an exemplary embodiment of the present invention is shown, wherein the fuel cell system has an anode gas loop for a fuel cell stack;

[0027] Figure 2 A schematic view of an ejector of an anode gas loop according to an exemplary embodiment of the present invention is shown;

[0028] Figure 3 A schematic block diagram of an anode gas loop according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and a number of exemplary embodiments.

[0030] It should be understood that, in this document, the expressions "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance, nor should they be understood as implicitly indicating the number of technical features indicated. Features defined as "first" or "second" may explicitly or implicitly indicate that at least one of the features is included.

[0031] In this specification, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate, or the internal communication of two elements. For ordinary technicians in this field, the meanings of the above terms in this disclosure can be understood according to the circumstances.

[0032] Figure 1 A schematic block diagram of a fuel cell system 1000 according to an exemplary embodiment of the present invention is shown. The fuel cell system 1000 has an anode gas loop 200 for a fuel cell stack 100 . Figure 2 A schematic view of the ejector 40 of the anode gas loop 200 according to an exemplary embodiment of the present invention is shown. Figure 3 A schematic block diagram of an anode gas loop 200 according to an exemplary embodiment of the present invention is shown.

[0033] like Figure 1As shown, the fuel cell system 1000 includes a fuel cell stack 100, which is the core part of the fuel cell system 1000 and has a plurality of stacked fuel cell monomers, in which an electrochemical reaction between hydrogen and oxygen in the air is carried out to generate electrical energy, wherein the fuel cell stack 100 has an anode and a cathode, hydrogen is supplied to the anode through an anode inlet 110 and is discharged from an anode outlet 120, and air is supplied to the cathode through a cathode inlet 130 and is discharged from a cathode outlet 140.

[0034] like Figure 1 As shown, the fuel cell system 1000 includes an anode gas loop 200 according to the present invention, which is connected between the anode inlet 110 and the anode outlet 120 of the fuel cell stack 100 and is configured to supply hydrogen to the anode of the fuel cell stack 100 via the anode inlet 110 and discharge unconsumed hydrogen via the anode outlet 120. The various components of the anode gas loop 200 will be described in detail below.

[0035] like Figure 1 As shown, the anode gas loop 200 includes a hydrogen supply device 10, a gas supply pipeline 20 and an exhaust pipeline 30, wherein the gas supply pipeline is connected between the hydrogen supply device 10 and the anode inlet 110 of the fuel cell stack 100, wherein the hydrogen supply device 10 is particularly configured as a high-pressure hydrogen storage tank and is used to provide high-pressure hydrogen, which is transported to the anode of the fuel cell stack 100 through the gas supply pipeline 20, and the exhaust pipeline 30 is connected to the anode outlet 120 of the fuel cell stack 100 to discharge unconsumed hydrogen and possible water generated by the reaction and nitrogen generated by diffusion from the fuel cell stack 100, wherein the exhaust pipeline 30 has a first exhaust branch 31 and a second exhaust branch 32 connected in parallel. In addition, it is also possible that the exhaust pipeline 30 also has a third exhaust branch 33, which leads to the external environment to discharge product water and nitrogen from the fuel cell system 1000.

[0036] like Figure 1 and Figure 2As shown, the anode gas loop 200 includes an ejector 40, which is arranged in the gas supply line 20 and is constructed to draw hydrogen in the first exhaust branch 31 into the gas supply line 20 to achieve recirculation of unconsumed hydrogen, wherein the ejector 40 is particularly constructed in the form of a venturi tube and has a first ejector inlet 41, a second ejector inlet 42 and an ejector outlet 43, wherein the first ejector inlet 41 is connected to the hydrogen supply device 10 through the gas supply line 20, the second ejector inlet 42 is connected to the first exhaust branch 31 of the exhaust line 30, and the ejector outlet 43 is connected to the anode inlet 110. Thus, the high-pressure hydrogen from the hydrogen supply device 10 flows out of the nozzle 44 through the first injection inlet 41 as a primary fluid, and the primary fluid draws the surrounding fluid with lower pressure and drives the low-pressure hydrogen in the first exhaust branch 31 to flow in from the second injection inlet 42, and the low-pressure hydrogen is also called the secondary fluid. Then the primary fluid and the secondary fluid are fully mixed and momentum exchanged in the mixing chamber 45, so that the velocity distribution of the two fluids becomes uniform and the fluid pressure is increased. Then the mixed fluid flows into the diffusion chamber 46, where the velocity of the fluid is reduced and the pressure is further increased, thereby effectively increasing the pressure of the recycled hydrogen from the exhaust pipe 30. However, especially when the operating power of the fuel cell stack 100 is low, the pressure of the hydrogen flowing in from the first injection inlet 41 is relatively low, which results in the poor injection effect or pressurization effect of the ejector 40, which cannot meet the pressure requirement of hydrogen recirculation.

[0037] like Figure 1 As shown, the anode gas loop 200 includes a hydrogen circulation pump 50, which is arranged in the second exhaust branch 32 of the exhaust pipeline 30 and is configured to draw hydrogen in the second exhaust branch 32 into the gas supply pipeline 20 to achieve recirculation of unconsumed hydrogen, wherein the second exhaust branch 32 is connected to the gas supply pipeline 20 downstream of the ejection outlet 43 of the ejector 40. Here, the hydrogen circulation pump 50, as an electric drive pump, can adapt to the different operating powers of the fuel cell stack 100 by adjusting the speed, so that the desired circulation boosting effect can still be achieved when the operating power of the fuel cell stack 100 is low. However, the hydrogen circulation pump 50 will generate non-negligible parasitic power when it is running, which will reduce the output power of the fuel cell system 1000 to a certain extent. Here, the hydrogen circulation pump 50 can be constructed in a variety of structural forms such as centrifugal, vortex, roots, and screw.

[0038] like Figure 1As shown, the anode gas loop 200 includes a switching component 60, which can be arranged in the first exhaust branch 31 and the second exhaust branch 32 and is constructed to implement switching between a series connection mode and a parallel connection mode of the hydrogen circulation pump 50 and the ejector 40, wherein, in the series connection mode, as shown in the right half of the switching component 60, the hydrogen circulation pump 50 and the ejector 40 sequentially pump the same flow of recycled hydrogen in the exhaust pipe 30, so that the recycled hydrogen undergoes two pressure increases in succession, which can achieve a significantly improved pressurization effect of the recycled hydrogen; and in the parallel connection mode, as shown in the left half of the switching component 60, the recycled hydrogen in the first exhaust branch 31 is pumped by the ejector 40, and the recycled hydrogen in the second exhaust branch 32 is pumped by the hydrogen circulation pump 50 at the same time, which can achieve a significantly increased flow rate of the recycled hydrogen.

[0039] Therefore, the anode gas loop 200 according to the utility model can fully utilize the advantages of the ejector 40 and the hydrogen circulation pump 50, and flexibly select the connection mode of the ejector 40 and the hydrogen circulation pump 50 according to different working conditions to optimize the hydrogen circulation effect, thereby improving the working performance of the fuel cell system 1000.

[0040] Exemplarily, the switching assembly 60 is configured such that when the operating power of the fuel cell stack 100 is less than the preset power, the switching assembly 60 switches to the series connection mode, in which case the hydrogen circulation pump 50 can assume the main pressurization function and make up for the disadvantage of the poor ejection effect of the ejector 40 at low operating power; and when the operating power of the fuel cell stack 100 is greater than or equal to the preset power, the switching assembly 60 switches to the parallel connection mode, so that the ejector 40 assumes a part of the flow of hydrogen recirculation, thereby reducing the adverse effect of the parasitic power of the hydrogen circulation pump 50 on the output power of the fuel cell system 1000. Here, the preset power can be obtained in advance from experimental data and / or empirical data.

[0041] For example, Figure 3As shown, the switching component 60 has a first switch valve 61 arranged in the first exhaust branch 31, a second switch valve 62 arranged in the second exhaust branch 32, and a third switch valve 63, wherein the third switch valve is arranged in the bypass branch 34 between the first exhaust branch 31 and the second exhaust branch 32, and the circulation pump outlet of the hydrogen circulation pump 50 is connected to the first exhaust branch 31 through the bypass branch 34, wherein, viewed along the flow direction of the recirculated hydrogen, the first switch valve 61 is located upstream of the bypass branch 34, and the second switch valve 62 is located downstream of the bypass branch 34. Here, in the series connection mode, the first switch valve 61 and the second switch valve 62 are closed and the third switch valve 63 is connected, so that the hydrogen in the exhaust pipe 30 can only flow through the hydrogen circulation pump 50 in the second exhaust branch 32 first, and then flow to the ejector 40 via the bypass branch 34 and the first exhaust branch 31; while in the parallel connection mode, the first switch valve 61 and the second switch valve 62 are connected and the third switch valve 63 is closed, so that the hydrogen in the exhaust pipe 30 can flow to the ejector 40 via the first exhaust branch 31 and flow to the gas supply pipe 20 via the hydrogen circulation pump 50 of the second exhaust branch 32, respectively, but cannot flow through the bypass branch 34. Here, of course, other structural forms of the switching component 60 that are considered meaningful by those skilled in the art can also be considered, such as being constructed as an integrated electromagnetic reversing valve.

[0042] For example, Figure 3 As shown, the switching assembly 60 further has a fourth switch valve 64 arranged in the third exhaust branch 33, and the switch valve is configured to control the on-off of the third exhaust branch 33 so as to selectively discharge the gas in the exhaust line 30 to the external environment as needed.

[0043] For example, Figure 3As shown, the switching assembly 60 additionally has a three-way valve 65 arranged between the first exhaust branch 31 and the second exhaust branch 32, and the flow of the exhaust line 30 to the first exhaust branch 31 and the second exhaust branch 32 can be adjusted by controlling the opening of the three-way valve. This is particularly applicable to the parallel connection mode of the hydrogen circulation pump 50 and the ejector 40, so as to adjust the workload of the hydrogen circulation pump 50 and the ejector 40 in a targeted manner. Here, the opening of the three-way valve 65 can be adjusted in particular according to the operating power of the fuel cell stack 100, wherein the greater the operating power of the fuel cell stack 100, the greater the opening of the three-way valve 65 to the first exhaust branch 31, so that more hydrogen in the exhaust line 30 is pumped through the ejector 40, which can make full use of the advantages of the ejector 40 at high operating power and reduce the adverse effect of the parasitic power of the hydrogen circulation pump 50 on the output power of the fuel cell system 1000 as much as possible. It is conceivable that the three-way valve 65 is integrated with the first switching valve 31 to reduce the number of parts and assembly costs. Of course, it is also possible that the switching assembly 60 also includes other three-way valves, such as a three-way valve arranged between the second exhaust branch 32 and the bypass branch 34.

[0044] For example, Figure 1 and Figure 3 As shown, the anode gas loop 200 further includes a gas-liquid separator 70, which is arranged upstream of the first exhaust branch 31 and the second exhaust branch 32 in the exhaust pipeline 30 and is configured to filter water out of the anode exhaust. Here, the gas-liquid separator 70 can be connected to the third exhaust branch 33 through an additional pipeline to discharge the filtered water to the external environment.

[0045] For example, Figure 1 and Figure 3 As shown, the anode gas loop 200 further includes a proportional valve 80 to adjust the pressure and flow of hydrogen gas flowing from the hydrogen supply device 10 into the gas supply pipeline 20, wherein the proportional valve 80 is particularly configured as a pressure reducing valve. In addition, the anode gas loop 200 may also include a hydrogen injector, which is configured to further reduce the pressure of the hydrogen gas to the pressure required for the operation of the fuel cell stack 100.

[0046] like Figure 1 As shown, the fuel cell system 1000 further includes a cathode gas loop 300, which is connected between the cathode inlet 130 and the cathode outlet 140 of the fuel cell stack and is configured to supply air containing oxygen to the cathode of the fuel cell stack 100 via the cathode inlet 130 and discharge the reacted air via the cathode outlet 140. Here, an air compressor may be arranged in the cathode gas loop 300.

[0047] The above explanation of the embodiments only describes the present invention within the framework of the examples. Of course, as long as it makes sense technically, the individual features of the embodiments can be freely combined with each other without departing from the framework of the present invention.

[0048] Other advantages and alternative embodiments of the present invention are obvious to those skilled in the art. Therefore, the present invention in its broader sense is not limited to the specific details, representative structures and exemplary embodiments shown and described. On the contrary, those skilled in the art can make various modifications and substitutions without departing from the basic spirit and scope of the present invention.

Claims

1. An anode gas loop (200) for a fuel cell stack (100), characterized in that: The anode gas loop (200) comprises at least: - a hydrogen supply device (10); - a gas supply pipeline (20), the gas supply pipeline (20) being configured to be connected between the hydrogen supply device (10) and the anode inlet (110) of the fuel cell stack (100); - an ejector (40) arranged in the gas supply pipeline (20), the ejector (40) having a first ejection inlet (41), a second ejection inlet (42) and an ejection outlet (43), wherein the first ejection inlet (41) is connected to the hydrogen supply device (10), and the ejection outlet (43) is connected to the anode inlet (110); - an exhaust pipeline (30), the exhaust pipeline (30) being configured to be connected to the anode outlet (120) of the fuel cell stack (100), wherein the exhaust pipeline (30) has a first exhaust branch (31) and a second exhaust branch (32), the first exhaust branch (31) being connected to the second ejection inlet (42) of the ejector (40), and the second exhaust branch (32) being connected to the gas supply pipeline (20) downstream of the ejection outlet (43); - a hydrogen circulation pump (50), which is arranged in the second exhaust branch (32); and - a switching assembly (60), the switching assembly (60) being configured and adapted to implement switching between a series connection mode and a parallel connection mode of the ejector (40) and the hydrogen circulation pump (50).

2. The anode gas circuit (200) according to claim 1, characterized in that: The switching component (60) comprises at least a first switch valve (61) arranged in the first exhaust branch (31), a second switch valve (62) arranged in the second exhaust branch (32), and a third switch valve (63) arranged in a bypass branch (34) between the first exhaust branch (31) and the second exhaust branch (32), and the circulation pump outlet of the hydrogen circulation pump (50) is connected to the first exhaust branch (31) through the bypass branch (34), wherein, in the series connection mode, the first switch valve (61) and the second switch valve (62) are turned off and the third switch valve (63) is turned on, and in the parallel connection mode, the first switch valve (61) and the second switch valve (62) are turned on and the third switch valve (63) is turned off.

3. The anode gas circuit (200) according to claim 2, characterized in that: The switching arrangement (60) additionally has a three-way valve (65) which is arranged between the first exhaust branch (31) and the second exhaust branch (32).

4. The anode gas circuit (200) according to claim 3, characterized in that: The three-way valve (65) is integrally constructed with the first switch valve (61); and / or The opening degree of the three-way valve (65) is adjusted according to the operating power of the fuel cell stack (100).

5. The anode gas circuit (200) according to any one of claims 1 to 4, characterized in that: The switching component (60) is configured to switch to the series connection mode when the operating power of the fuel cell stack (100) is less than a preset power, and to switch to the parallel connection mode when the operating power of the fuel cell stack (100) is greater than or equal to the preset power.

6. The anode gas circuit (200) according to any one of claims 1 to 4, characterized in that: The exhaust gas line (30) has a third exhaust gas branch (33), which leads to the external environment, wherein a fourth switching valve (64) is arranged in the third exhaust gas branch (33).

7. The anode gas circuit (200) according to any one of claims 1 to 4, characterized in that: The anode gas loop (200) comprises a gas-liquid separator (70), and the gas-liquid separator (70) is arranged in the exhaust pipeline (30) upstream of the first exhaust branch (31) and the second exhaust branch (32).

8. The anode gas circuit (200) according to any one of claims 1 to 4, characterized in that: The anode gas loop (200) comprises a proportional valve (80) and / or a hydrogen injector to adjust the pressure and flow rate of hydrogen flowing from the hydrogen supply device (10) into the gas supply pipeline (20).

9. The anode gas circuit (200) according to any one of claims 1 to 4, characterized in that: The hydrogen supply device (10) is configured as a high-pressure hydrogen storage tank; and / or The ejector (40) is constructed in the form of a venturi tube.

10. A fuel cell system (1000), characterized in that: The fuel cell system (1000) comprises at least: - A fuel cell stack (100); - an anode gas circuit (200) according to any one of claims 1 to 9; and - a cathode gas circuit (300), the cathode gas circuit (300) being connected between the cathode inlet (130) and the cathode outlet (140) of the fuel cell stack (100).

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