Circulation loop, cathode system and fuel cell system

Abstract

The utility model provides a circulation loop, a cathode system and a fuel cell system. The circulation loop comprises a cathode of a fuel cell stack of the fuel cell system and a bidirectional circulation pump, a first end of the bidirectional circulation pump is connected to a cathode inlet of the fuel cell stack, and a second end of the bidirectional circulation pump is connected to a cathode outlet of the fuel cell stack. The bidirectional circulation pump is configured to circulate air in the cathode in a first direction from the cathode inlet to the cathode outlet and to circulate air in the cathode in a second direction from the cathode outlet to the cathode inlet. By arranging the two-way circulating pump, the cathode purging efficiency in the shutdown process of the fuel cell system can be improved, the reliability of the fuel cell system can be improved, and the service life of the fuel cell system can be prolonged.

Description

Technical Field

[0001] The present disclosure relates to the technical field of fuel cells, and more particularly, to a circulation loop for the cathode of a fuel cell system and a fuel cell system employing the circulation loop. Background Art

[0002] Fuel cells have the advantages of high energy conversion efficiency and pollution-free emissions, and have important applications in many fields. For example, fuel cells have become a type of widely used automotive power battery. During the operation of a fuel cell system, hydrogen in the anode of the fuel cell stack and oxygen in the cathode react on the membrane electrode to generate electrical energy, and water is generated concomitantly.

[0003] Water in the fuel cell stack is mainly generated at the cathode. If this part of the water is not removed, it may affect the next start-up of the fuel cell system. For example, in the case of a relatively low ambient temperature, the water accumulated in the cathode may freeze, resulting in the inability of the air in the cathode to enter the membrane electrode, making the fuel cell system unable to start. In addition, the volume expansion during the water freezing process may also damage the structure of the fuel cell stack. Summary of the Utility Model

[0004] To solve the problem of excessive local water in the fuel cell stack during the shutdown process of the fuel cell system, embodiments of the present disclosure provide a circulation loop for the cathode of a fuel cell system and a fuel cell system employing the circulation loop, which can make the purging of water in the cathode more rapid and make the water evenly distributed in the cathode, avoiding excessive local water or local over-drying in the cathode.

[0005] In a first aspect of the present disclosure, there is provided a circulation loop for the cathode of a fuel cell system. It includes the cathode of the fuel cell stack of the fuel cell system and a two-way circulation pump; wherein the first end of the two-way circulation pump is connected to the cathode inlet of the fuel cell stack, the second end of the two-way circulation pump is connected to the cathode outlet of the fuel cell stack, and the two-way circulation pump is configured to circulate the air in the cathode in a first direction from the cathode inlet to the cathode outlet, and to circulate the air in the cathode in a second direction from the cathode outlet to the cathode inlet.

[0006] Optionally, an inlet stop valve is provided on the pipeline connecting the first end and the cathode inlet, and an outlet stop valve is provided on the pipeline connecting the second end and the cathode outlet.

[0007] Optionally, the first end is connected to the cathode gas supply pipeline of the cathode through an inlet three-way valve, and the second end is connected to the cathode exhaust pipeline of the cathode through an outlet three-way valve.

[0008] Optionally, a water separator is provided between the first end of the two-way circulation pump and the cathode inlet.

[0009] Optionally, a water separator is provided between the second end of the bidirectional circulation pump and the cathode outlet.

[0010] In a second aspect of the present disclosure, a cathode system for a fuel cell system is provided, including an air supply device, a cathode supply gas pipeline, a cathode exhaust gas pipeline, and a circulation loop according to the first aspect of the present disclosure, wherein the air supply device is connected to the cathode inlet of the fuel cell stack of the fuel cell system through the cathode supply gas pipeline to supply air to the cathode of the fuel cell stack; the cathode exhaust gas pipeline is arranged to connect the cathode outlet of the fuel cell stack to the external environment of the fuel cell system to discharge the waste gas in the cathode of the fuel cell stack; the first end of the bidirectional circulation pump in the circulation loop is connected to the cathode supply gas pipeline and thus connected to the cathode inlet, and the second end of the bidirectional circulation pump is connected to the cathode exhaust gas pipeline and thus connected to the cathode outlet.

[0011] Optionally, an upstream shut-off valve is provided on the cathode supply gas pipeline, and an exhaust throttle valve is provided on the cathode exhaust gas pipeline; the first connection between the first end and the cathode supply gas pipeline is located between the upstream shut-off valve and the cathode inlet, and the second connection between the second end and the cathode exhaust gas pipeline is located between the exhaust throttle valve and the cathode outlet; and an inlet shut-off valve is provided between the first end and the first connection, and an outlet shut-off valve is provided between the second end and the second connection.

[0012] Optionally, an inlet three-way valve is provided on the cathode supply gas pipeline, and the first end is connected to the cathode supply gas pipeline through the inlet three-way valve; and an outlet three-way valve is provided on the cathode exhaust gas pipeline, and the second end is connected to the cathode exhaust gas pipeline through the outlet three-way valve.

[0013] Optionally, the circulation loop further includes a water separator, which is arranged on the pipeline connecting the first end of the bidirectional circulation pump and the cathode supply gas pipeline, or the water separator is arranged on the pipeline connecting the second end of the bidirectional circulation pump and the cathode exhaust gas pipeline.

[0014] In a third aspect of the present disclosure, a fuel cell system is provided, including: a fuel cell stack, which includes a cathode and an anode, and a proton exchange membrane is arranged between the cathode and the anode; an anode system, which is configured to supply hydrogen to the anode of the fuel cell stack; and a cathode system according to the second aspect of the present disclosure. Description of the Drawings

[0015] In conjunction with the accompanying drawings and with reference to the following detailed description, the above and other features, advantages, and aspects of the embodiments of the present disclosure will become more apparent. In the drawings, the same or similar reference numerals denote the same or similar elements. It should be noted that the elements in the respective drawings are not necessarily drawn to scale strictly with each other, and they are merely for the purpose of clear illustration and not restrictive. Among them:

[0016] Figure 1 shows a schematic diagram of a fuel cell system in some embodiments of the present disclosure;

[0017] Figure 2A shows a schematic diagram of a circulation loop in some embodiments of the present disclosure;

[0018] Figure 2B shows a schematic diagram of the air flow direction in a circulation loop in some embodiments of the present disclosure;

[0019] Figure 2C shows a schematic diagram of another air flow direction in a circulation loop in some embodiments of the present disclosure;

[0020] Figure 2D shows a schematic diagram of another circulation loop in some embodiments of the present disclosure;

[0021] Figure 3 shows a schematic diagram of yet another circulation loop in some embodiments of the present disclosure;

[0022] Figure 4 shows a schematic diagram of yet another circulation loop in some embodiments of the present disclosure;

[0023] Figure 5 shows a schematic diagram of yet another circulation loop in some embodiments of the present disclosure;

[0024] Figure 6 shows a schematic diagram of a cathode system for a fuel cell system in some embodiments of the present disclosure;

[0025] Figure 7 shows a schematic diagram of yet another cathode system in some embodiments of the present disclosure. Detailed Embodiments

[0026] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not used to limit the protection scope of the present disclosure.

[0027] In addition, without conflict, the features in the embodiments of the present application may be combined with each other. In different drawings, the same components are denoted by the same reference numerals, and for the sake of brevity, other components are omitted, but this does not mean that the fuel cell system, its cathode system, and the circulation loop in the present application cannot include other components. It should be understood that the dimensions, proportional relationships, and the number of components in the drawings are not limitations on the present application.

[0028] In the description of the embodiments of the present disclosure, the term "including" and its like should be understood as an open inclusion, that is, "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. There may also be other explicit and implicit definitions hereinafter.

[0029] The orientation terms such as up, down, left, right, front, back, front side, back side, top, bottom, etc. mentioned or possibly mentioned in this specification are defined relative to the structures shown in the respective drawings. They are relative concepts and may therefore change accordingly depending on their different positions and usage states. Therefore, these or other orientation terms should not be construed as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for descriptive and differentiating purposes and cannot be understood as indicating or implying the relative importance of the corresponding components.

[0030] As mentioned above, in order not to damage the fuel cell stack and ensure the normal startup of the fuel cell system, it is necessary to remove the water in the cathode. In the related art, the cathode can be purged with air during the shutdown process of the fuel cell system to remove the moisture in the cathode. However, this purging is unidirectional, and air enters the cathode from the cathode inlet and flows out from the cathode outlet, and water is also blown from the cathode inlet to the cathode outlet. This may cause the water distribution in the cathode to be uneven, and may result in a situation where the cathode inlet is too dry and there is too much water at the cathode outlet, which will affect the performance of the fuel cell stack. For example, if the cathode is purged too dry, it may reduce the startup performance of the fuel cell system and shorten the life of the membrane electrode, while if there is too much remaining moisture in the cathode, problems such as icing may occur.

[0031] The circulation loop for the cathode of a fuel cell system provided by an embodiment of the present disclosure is provided with a bidirectional circulation pump whose two ends are respectively connected to the cathode inlet and the cathode outlet of the fuel cell stack. During the shutdown process of the fuel cell system, through the bidirectional circulation pump in this circulation loop, the air in the cathode of the fuel cell stack can be alternately circulated along a first direction from the cathode inlet to the cathode outlet and a second direction from the cathode outlet to the cathode inlet, so that the water in the cathode can be evenly distributed in the cathode. In this way, the situation of excessive drying or excessive water in the cathode during the shutdown process can be avoided, thereby improving the performance and stability of the fuel cell system.

[0032] Figure 1 FIG. schematically shows a schematic diagram of a fuel cell system 100 in some embodiments of the present disclosure, and the circulation loop in some embodiments of the present disclosure can be used in this fuel cell system 100. Refer to Figure 1 , the fuel cell system 100 may include a fuel cell stack 101. The fuel cell stack 101 may include a cathode 102, an anode 103, and a membrane electrode 104. Oxygen in the cathode 102 and hydrogen in the anode 103 may undergo an electrochemical reaction on the membrane electrode 104 to generate electric energy. The fuel cell system 100 may further include a direct current / direct current (DC / DC) converter 120. The DC / DC converter 120 is used to adjust the voltage and current output by the fuel cell stack 101 and can convert the varying voltage provided by the fuel cell stack 101 into a stable output voltage. It should be understood that Figure 1 the fuel cell stack 101 in FIG. is only a schematic illustration for explanation and cannot be a limitation to the present disclosure. For example, in some embodiments, the fuel cell stack 101 may include a plurality of monolithic cells connected in series, and each monolithic cell may include a cathode, an anode, and a membrane electrode.

[0033] The fuel cell system 100 may further include a hydrogen injector 105, an anode water separator 106, a hydrogen circulation pump 107, a drain valve 108, and a hydrogen discharge valve 109. Among them, the hydrogen injector 105 is used to supply hydrogen from the hydrogen storage system to the anode 103 and control the pressure and flow rate of the hydrogen. The anode water separator 106 is used to separate the liquid water in the gas at the outlet of the anode 103 and discharge the liquid water through the drain valve 108. The hydrogen discharge valve 109 may also be referred to as a purge valve and is used to discharge the impurity gas when the concentration of the impurity gas (such as nitrogen) in the anode 103 becomes high. The hydrogen circulation pump 107 is used to circulate the unreacted hydrogen at the outlet of the anode 103 to the inlet of the anode 103.

[0034] The fuel cell system 100 may further include a filter 110, an air compressor 111, an intercooler 112, an upstream cut-off valve 113, an exhaust throttle valve 114, and a bypass valve 115. Among them, the filter 110, which can be referred to as an air filter, is used to filter particulate impurities in the air to avoid clogging the pipelines of the fuel cell system 100. The air compressor 111 is used to pressurize the air and supply air to the cathode 102 of the fuel cell stack 101. The intercooler 112 is used to cool the compressed air provided by the air compressor 111. The upstream cut-off valve 113 is in an open state during the operation of the fuel cell system 100 and is closed when the fuel cell system 100 is in a shutdown state. The exhaust throttle valve 114 is used to discharge the reacted cathode gas and can also adjust the gas pressure at the cathode 102 outlet and the flow rate of the gas supplied to the fuel cell stack 101. The bypass valve 115 can be opened when the upstream cut-off valve 113 is closed to discharge the air provided by the air compressor 111.

[0035] In the fuel cell system 100, the hydrogen injector 105, the water separator 106, the hydrogen circulation pump 107, the drain valve 108, the hydrogen discharge valve 109, and the anode 103 can be connected by pipelines to jointly form the anode system (which can also be referred to as the anode loop) in the fuel cell system 100. The filter 110, the air compressor 111, the intercooler 112, the upstream cut-off valve 113, the exhaust throttle valve 114, the bypass valve 115, and the cathode 102 are connected by pipelines to jointly form the cathode system (which can also be referred to as the cathode loop) in the fuel cell system 100. In the fuel cell system 100, the water and waste gas discharged from the anode system and the air and waste gas discharged from the cathode system can be discharged from the fuel cell system 100 through the tail pipe 116. In Figure 1 The flow directions of the pipelines and the gas or liquid in the pipelines are represented in the form of arrows.

[0036] In some embodiments of the present disclosure, the cathode system of the fuel cell system 100 may further include a circulation loop formed by a bidirectional circulation pump 130 and the cathode 102. Among them, the bidirectional circulation pump 130 is used to circulate the air in the cathode 102, and can make the air in the cathode 102 circulate along the direction from the cathode inlet to the cathode outlet, or can make the air in the cathode 102 circulate along the direction from the cathode outlet to the cathode inlet. In the embodiments of the present disclosure, the bidirectional circulation pump 130 is a device that can realize bidirectional gas transportation, and may include, but is not limited to, a piston-type bidirectional circulation pump, a diaphragm-type bidirectional circulation pump, a rotary-type bidirectional circulation pump, etc.

[0037] During the shutdown process of the fuel cell system 100, the cathode system performs an air purge. The air compressor 111, the upstream cut-off valve 113, and the exhaust throttle valve 114 are opened, and air flows into the cathode, thereby discharging the water in the cathode. The bidirectional circulation pump 130 can pump the air discharged from the cathode outlet back to the cathode inlet through the circulation loop at this stage, so as to increase the air flow rate into the cathode. In this way, the water in the cathode can be discharged more quickly, and the purge time can be shortened.

[0038] After the purge is completed, the upstream cut-off valve 113 and the exhaust throttle valve 114 are closed, and the cathode 102 is in a relatively closed state. The bidirectional circulation pump 130 can alternately pump air in two directions, so that the gas in the cathode 102 circulates alternately in the direction from the cathode inlet to the cathode outlet and in the direction from the cathode outlet to the cathode inlet, thereby making the remaining water in the cathode 102 evenly distributed and avoiding the situation of local over-drying or local water accumulation.

[0039] It should be understood that Figure 1 The shown fuel cell system 100 is only an example of the embodiments of the present disclosure and cannot be a limitation to the embodiments of the present disclosure. For example, in some embodiments, the oxidizing gas in the cathode 102 of the fuel cell system 100 can be other types of gases, such as oxygen. In some embodiments, the fuel gas in the anode 103 can be other types of gases, such as methanol. In the embodiments of the present disclosure, the names of the components in the fuel cell system 100 are only examples. In some embodiments, components with the same or similar functions can have different names.

[0040] In some embodiments, the fuel cell system 100 may further include more or fewer components. For example, it may further include a pressure sensor for detecting pressure and a temperature sensor for detecting temperature. It should be understood that the solutions provided in the embodiments of the present disclosure can also be applied to other types of fuel cell systems. The fuel cell systems in the embodiments of the present disclosure can be applied to various scenarios and can be configured as power sources or auxiliary power in various devices, including but not limited to vehicles, yachts, aerospace equipment, underwater power equipment, etc.

[0041] Next, in conjunction with Figures 2A to 5 the circulation loop in the embodiments of the present disclosure will be described. Figure 2A The schematic diagram of the circulation loop 200 in some embodiments of the present disclosure is shown. As Figure 2AAs shown, the circulation loop 200 includes a bidirectional circulation pump 130 and the cathode 102 in the fuel cell stack 101 of the fuel cell system. One end of the bidirectional circulation pump 130 is connected to the cathode air supply pipeline 203 of the cathode 102, thus connecting to the cathode inlet 201; the other end is connected to the cathode exhaust pipeline 204 of the cathode 102, thus connecting to the cathode outlet 202. The connection between the bidirectional circulation pump 130 and the cathode air supply pipeline 201 and the cathode exhaust pipeline 202 can use pipelines, so that gas flow can be achieved between the bidirectional circulation pump 130 and the cathode 102.

[0042] During the normal operation of the fuel cell system, air in the cathode system enters the cathode 102 from the cathode inlet 201 and then flows out from the cathode outlet 202. For the convenience of description, this flow direction of air is called the first direction, and the opposite air flow direction is called the second direction. In some embodiments, as Figure 2B shown, the bidirectional circulation pump 130 can pump air in the cathode 102 out of the cathode outlet 202 and then transport it to the cathode inlet 201, so that the air in the cathode 102 flows in the first direction. In some embodiments, as Figure 2B shown, the bidirectional circulation pump 130 can pump air in the cathode 102 out of the cathode inlet 201 and then transport it to the cathode outlet 202, so that the air in the cathode 102 flows in the second direction.

[0043] In some embodiments, during the cathode purge stage of the shutdown process of the fuel cell system, the bidirectional circulation pump 130 can make the air in the cathode 102 flow in the first direction, so as to increase the air flow rate in the cathode, accelerate the discharge of moisture, and thus be able to shorten the purge time and improve the purge efficiency. In some embodiments, after the cathode purge stage of the fuel cell system ends, the bidirectional circulation pump 130 can periodically change the air flow direction in the cathode 102, so that the air in the cathode 102 alternately flows along the first direction and the second direction. In this way, the remaining water after the purge can be evenly distributed in the cathode, avoiding local over-drying or local over-wetting in the cathode, thereby being able to improve the performance of the fuel cell stack and also avoiding damage to the fuel cell stack due to the freezing of excessive local water.

[0044] In Figure 2A 、 Figure 2B and Figure 2C , both ends of the bidirectional circulation pump 130 are respectively connected to the cathode air supply pipeline 203 and the cathode exhaust pipeline 204, thus forming the circulation loop 200. In some embodiments, as shown in Figure 2D it can be shown that the connection between both ends of the bidirectional circulation pump 130 and the cathode 102 can be independent of the cathode air supply pipeline 203 and the cathode exhaust pipeline 204.

[0045] Figure 3 FIG. shows a schematic diagram of yet another circulation loop 300 in some embodiments of the present disclosure. Compared with Figure 2A the shown circulation loop 200, in the circulation loop 300, an inlet stop valve 301 is added to the pipeline connecting one end of the bidirectional circulation pump 130 to the cathode inlet 201, and an outlet stop valve 302 is added to the pipeline connecting the other end of the bidirectional circulation pump 130 to the cathode outlet 202. Both the inlet stop valve 301 and the outlet stop valve 302 are bidirectional valves for disconnecting and conducting the air flow between the bidirectional circulation pump 130 and the cathode 102, and the inlet stop valve 301 and the outlet stop valve 302 can be opened and closed simultaneously.

[0046] Figure 4 FIG. shows a schematic diagram of yet another circulation loop 400 in some embodiments of the present disclosure. Compared with Figure 2A the shown circulation loop 200, in the circulation loop 400, one end of the bidirectional circulation pump 130 is connected to the cathode gas supply pipeline 203 through an inlet three-way valve 410, and the other end of the bidirectional circulation pump 130 is connected to the cathode exhaust gas pipeline 204 through an outlet three-way valve 420. The inlet three-way valve 410 can include three directions: direction 411, direction 412, and direction 413, and can be configured to conduct direction 411 and direction 413 simultaneously and cut off direction 412, or conduct direction 412 and direction 413 simultaneously and cut off direction 411, or conduct direction 411, direction 412, and direction 413 simultaneously. The outlet three-way valve 420 can include three directions: direction 421, direction 422, and direction 423, and can be configured to conduct direction 421 and direction 423 simultaneously and cut off direction 422, or conduct direction 421 and direction 422 simultaneously and cut off direction 423, or conduct direction 421, direction 422, and direction 423 simultaneously.

[0047] In some embodiments, a water separator may also be provided in the circulation loop of the cathode. Exemplarily, Figure 5 FIG. shows a schematic diagram of yet another circulation loop 500 in some embodiments of the present disclosure. Compared with Figure 2A the circulation loop 200 in, in the circulation loop 500, a water separator 501 is provided on the pipeline connecting one end of the bidirectional circulation pump 130 to the cathode 102. The water separator 501 can separate the water in the circulation loop 500, so as to keep the water content in the cathode within a suitable range. The water separator 501 can include, but is not limited to, a baffle type water separator, a cyclone type water separator, etc.

[0048] In some embodiments, the water separator 501 may be disposed on the pipeline connecting the bidirectional circulation pump 130 and the cathode outlet 202. In some embodiments, the water separator 501 may be disposed on the pipeline connecting the bidirectional circulation pump 130 and the cathode inlet 201. Through the water separator in the circulation loop 500, the water in the cathode can be discharged more quickly during the cathode purge stage in the shutdown process, improving the shutdown purge efficiency of the fuel cell system.

[0049] Embodiments of the present disclosure also provide a cathode system for a fuel cell system including the circulation loop described above. Figures 2A to 5 Figure 6 A schematic diagram of a cathode system 600 for a fuel cell system in some embodiments of the present disclosure is shown. Referring to Figure 6 , the cathode system 600 may include a filter 110, an air compressor 111, an intercooler 112, an upstream cutoff valve 113, an exhaust throttle valve 114, a bypass valve 115, a tailpipe muffler 116, a bidirectional circulation pump 130, a cathode supply gas pipeline 203, a cathode exhaust gas pipeline 204, an inlet cutoff valve 301, an outlet cutoff valve 302, and a water separator 501.

[0050] Among them, the filter 110, the air compressor 111, and the intercooler 112 may form an air supply device in the cathode system. The air supply device is connected to the cathode 102 through the cathode supply gas pipeline 203 and can supply air to the cathode 102. The cathode exhaust gas pipeline 204 connects the cathode 102 to the external environment, and the air and exhaust gas in the cathode 102 can be discharged to the external environment through the cathode exhaust gas pipeline 204.

[0051] In the cathode system 600, an upstream cutoff valve 113 is provided on the cathode supply gas pipeline 203, and an exhaust throttle valve 114 is provided on the cathode exhaust gas pipeline 204. One end of the bidirectional circulation pump 130 is connected to the cathode supply gas pipeline 203 through a pipeline, and the other end is connected to the cathode exhaust gas pipeline 204 through a pipeline. The first connection point of the bidirectional circulation pump 130 and the cathode supply gas pipeline 203 is located on the cathode supply gas pipeline 203, between the upstream cutoff valve 113 and the cathode inlet 201. The second connection point of the bidirectional circulation pump 130 and the cathode exhaust gas pipeline 204 is located on the cathode exhaust gas pipeline 204, between the exhaust throttle valve 114 and the cathode outlet 202.

[0052] ​Wherein, an inlet stop valve 301 is provided on the pipeline connecting one end of the bidirectional circulation pump 130 to the first connection point, and an outlet stop valve 302 is provided on the pipeline connecting the other end of the bidirectional circulation pump 130 to the second connection point. The water separator 501 can be provided between the inlet stop valve 301 and one end of the bidirectional circulation pump 130, or can be provided between the outlet stop valve 302 and the other end of the bidirectional circulation pump 130. In the cathode system 600, the bidirectional circulation pump 130, the water separator 501, the inlet stop valve 301, the outlet stop valve 302, the cathode 102, and the pipelines connecting these components together form a circulation loop of the cathode, which can make the air in the cathode 102 circulate along the first direction or the second direction.

[0053] Figure 7 Fig. shows a schematic diagram of another cathode system 700 in some embodiments of the present disclosure. Compared with Figure 6 the cathode system 600 in Figure 7 the shown cathode system 700, no upstream stop valve is provided on the cathode gas supply pipeline 203, no exhaust throttle valve is provided on the cathode exhaust pipeline, and no inlet stop valve and outlet stop valve are provided in the circulation loop. In the cathode system 700, an inlet three-way valve 410 is provided on the cathode gas supply pipeline 203, and the bidirectional circulation pump 130 is connected to the cathode gas supply pipeline 203 through the inlet three-way valve 410. An outlet three-way valve 420 is provided on the cathode exhaust pipeline 204, and the bidirectional circulation pump 130 is connected to the cathode exhaust pipeline 204 through the outlet three-way valve 420.

[0054] In the cathode system 700, the inlet three-way valve 410 is used to conduct or cut off the gas flow in the cathode gas supply pipeline 203, and can also be used to conduct or cut off the gas flow between the bidirectional circulation pump 130 and the cathode 102 in the circulation loop. The outlet three-way valve 420 is used to conduct or cut off the gas flow in the cathode exhaust pipeline 204, and can also be used to conduct or cut off the gas flow between the bidirectional circulation pump 130 and the cathode 102 in the circulation loop. In some embodiments, the three directions 411, 412, and 413 of the inlet three-way valve 410 can be conducted or cut off simultaneously, and the three directions 421, 422, and 423 of the outlet three-way valve 420 can also be conducted or cut off simultaneously. The rest of the cathode system 700 can be the same as the cathode system 600.

[0055] The present application has been described in detail in conjunction with specific embodiments. Obviously, the above description and the embodiments shown in the drawings should be understood as exemplary and do not constitute a limitation to the present application. Those skilled in the art should be clear that the embodiments described in this specification can be used in combination with each other, and the various components of the present invention can be combined arbitrarily, unless such combination will violate the purpose of the present invention or cannot be realized. Therefore, the present invention in its broader sense is not limited to the specific details, representative structures and exemplary examples shown and described.

Claims

1. A circulation loop for the cathode of a fuel cell system, characterized in that: include: A cathode (102) of a fuel cell stack (101) of a fuel cell system; as well as A bidirectional circulation pump (130), wherein a first end of the bidirectional circulation pump (130) is connected to a cathode inlet (201) of the fuel cell stack (101), and a second end of the bidirectional circulation pump (130) is connected to a cathode outlet (202) of the fuel cell stack (101), and the bidirectional circulation pump (130) is configured to circulate the air in the cathode (102) along a first direction from the cathode inlet (201) to the cathode outlet (202), and to circulate the air in the cathode (102) along a second direction from the cathode outlet (202) to the cathode inlet (201).

2. The circulation loop according to claim 1, characterized in that: An inlet stop valve (301) is provided on the pipeline connecting the first end and the cathode inlet (201), and an outlet stop valve (302) is provided on the pipeline connecting the second end and the cathode outlet (202).

3. The circulation loop according to claim 1, characterized in that: The first end is connected to the cathode gas supply line (203) of the cathode (102) through an inlet three-way valve (410), and the second end is connected to the cathode exhaust line (204) of the cathode (102) through an outlet three-way valve (420).

4. The circulation loop according to claim 1, characterized in that: A water separator is provided between the first end of the bidirectional circulation pump (130) and the cathode inlet (201).

5. The circulation loop according to claim 1, characterized in that: A water separator (501) is provided between the second end of the bidirectional circulation pump (130) and the cathode outlet (202).

6. A cathode system for a fuel cell system, characterized in that: include: An air supply device, a cathode air supply line (203), a cathode exhaust line (204) and a circulation loop according to claim 1, wherein The air supply device is connected to the cathode inlet (201) of the fuel cell stack of the fuel cell system through the cathode air supply line (203) to supply air to the cathode (102) of the fuel cell stack; The cathode exhaust line (204) is arranged to connect the cathode outlet (202) of the fuel cell stack to the external environment of the fuel cell system to discharge the exhaust gas in the cathode (102) of the fuel cell stack; and The first end of the bidirectional circulation pump (130) in the circulation loop is connected to the cathode gas supply line (203) and thus connected to the cathode inlet (201), and the second end of the bidirectional circulation pump (130) is connected to the cathode exhaust line (204) and thus connected to the cathode outlet (202).

7. The cathode system according to claim 6, characterized in that An upstream stop valve (113) is provided on the cathode gas supply pipeline (203), and an exhaust throttle valve (114) is provided on the cathode exhaust pipeline (204); A first connection between the first end and the cathode gas supply line (203) is located between the upstream stop valve (113) and the cathode inlet (201), and a second connection between the second end and the cathode exhaust line (204) is located between the exhaust throttle valve (114) and the cathode outlet (202); and An inlet stop valve (301) is provided between the first end and the first connection, and an outlet stop valve (302) is provided between the second end and the second connection.

8. The cathode system according to claim 6, characterized in that An inlet three-way valve (410) is provided on the cathode gas supply line (203), and the first end is connected to the cathode gas supply line (203) through the inlet three-way valve (410); and An outlet three-way valve (420) is provided on the cathode exhaust pipeline (204), and the second end is connected to the cathode exhaust pipeline (204) through the outlet three-way valve (420).

9. The cathode system according to claim 6, characterized in that The circulation loop also includes a water separator, which is arranged on the pipeline connecting the first end of the bidirectional circulation pump (130) and the cathode gas supply line (203), or the water separator is arranged on the pipeline connecting the second end of the bidirectional circulation pump (130) and the cathode exhaust line (204).

10. A fuel cell system, characterized in that: include: A fuel cell stack (101), the fuel cell stack (101) comprising a cathode (102) and an anode (103), wherein a proton exchange membrane (104) is arranged between the cathode (102) and the anode (103); an anode system configured to supply hydrogen to the anode (103) of the fuel cell stack (101); as well as A cathode system according to any one of claims 6 to 9.

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