Gas guiding member and fuel cell system

Abstract

The present application provides a gas guide member for guiding a gas mixed with liquid water into a stack of a fuel cell system, the stack being provided with a gas channel therein such that the gas is supplied from a first side of the gas channel into a plurality of cells, the gas guide member comprising: a body having an inlet end and an outlet end, the inner surface of the body defines a guide channel penetrating through the body, and the outlet end of the body is configured to be attached to a galvanic pile; the first fin and the second fin are symmetrically attached to the inner surface of the body, each fin is provided with a first end close to the inlet end and a second end close to the outlet end, and each fin spirally extends in opposite spiral directions at a set spiral angle from the corresponding first end to the corresponding second end; the gas channel is arranged such that gas is directed along each fin to a second side of the gas channel opposite the first side. The utility model also provides a fuel cell system comprising the gas guide component. According to the application, the phenomenon of water flooding in the electric pile can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell technology, and in particular to a gas guiding member for guiding a gas mixed with liquid water into an electric stack of a fuel cell system, and a fuel cell system comprising such a gas guiding member. BACKGROUND

[0002] With the development of fuel cell technology, the use of fuel cell systems (e.g. proton exchange membrane fuel cell (PEMFC) systems) as power sources is increasingly attracting the attention of researchers and the market. Generally, a fuel cell system comprises an electric stack, a fuel gas (e.g. hydrogen) supply device, an oxidizing gas (e.g. oxygen) supply device, etc. The electric stack generally comprises a plurality of cell units arranged side by side. During use, the fuel gas and the oxidizing gas react chemically in the presence of a catalyst in each cell unit to release electric power, which can drive an electric motor to output power.

[0003] For example, in the case of a PEMFC system, hydrogen is usually stored in a high-pressure hydrogen tank and is regulated by a jet pump before being supplied to the electric stack so as to provide an appropriate amount of hydrogen. However, the amount of hydrogen supplied is always more than that required for the reaction, and thus the hydrogen supplied to the electric stack cannot all participate in the reaction, and the excess hydrogen is discharged from the electric stack through an exhaust pipe. In order to ensure stable operation of the fuel cell system and improve fuel utilization, a circulation pump is usually used to deliver the excess hydrogen discharged from the electric stack back to the electric stack. Since the water (liquid water and water vapor) generated in the electric stack is also carried out of the electric stack when the excess hydrogen is discharged, a water separator is usually provided in the exhaust pipeline of the electric stack. The water separator can remove the liquid water mixed in the gas discharged from the electric stack to avoid the liquid water from re-entering the electric stack. However, for example during dynamic operation, the efficiency of the water separator can be reduced, and thus some liquid water can escape from the water separator and re-enter the electric stack through the circulation pump, which can cause a "flooding" phenomenon (i.e. the reaction gas passage in the cell unit is blocked by liquid water) in the electric stack, especially in one or more cell units close to the inlet of the gas passage of the electric stack. On the other hand, since the temperature downstream of the water separator is generally lower than that upstream of the water separator, some liquid water can also condense downstream of the water separator, and these condensed water can also enter the electric stack and further aggravate the "flooding" phenomenon.

[0004] It should be noted that, in addition to PEMFC systems, in fuel cell systems using other fuels (e.g. ammonia, coal gas, natural gas, biomass gas, etc.), as long as water is generated in the electric stack, similar problems also exist.

[0005] Therefore, there is a need to improve the existing fuel cell system to avoid the "flooding" phenomenon in the electric stack. Content of the Utility Model

[0006] The present application aims to propose an improved gas guiding member and fuel cell system to overcome the above technical problems.

[0007] To this end, according to an aspect of the present application, there is provided a gas guiding member for guiding a gas mixed with liquid water into an electric stack of a fuel cell system, the electric stack comprising a plurality of cell units arranged side by side, a gas passage being provided within the electric stack such that the gas is supplied into the plurality of cell units from a first side of the gas passage, wherein the gas guiding member comprises: a body having an inlet end and an outlet end, an inner surface of the body defining a guiding passage therethrough, the outlet end of the body being configured for attachment with the electric stack to communicate the guiding passage with the gas passage; and a first fin and a second fin symmetrically attached on the inner surface of the body, each of the first fin and the second fin having a first end proximate to the inlet end and a second end proximate to the outlet end, and each of the first fin and the second fin spirally extends in opposite spiral directions at a set spiral angle from the respective first end towards the respective second end, such that the gas is guided along the first fin and the second fin to a second side of the gas passage opposite to the first side.

[0008] According to an embodiment of the present application, the spiral angle is in the range of 30 degrees to 60 degrees.

[0009] According to an embodiment of the present application, the first end of the first fin and the first end of the second fin are connected to each other to form a ridge.

[0010] According to an embodiment of the present application, a distance between the second end of the first fin and the second end of the second fin is less than 70% of a diameter of the guiding passage.

[0011] According to an embodiment of the present application, a height of each of the first fin and the second fin gradually decreases from the respective first end towards the respective second end.

[0012] According to an embodiment of the present application, the height of each of the first fin and the second fin at the respective first end is in the range of 30% to 50% of the diameter of the guiding passage.

[0013] According to an embodiment of the present application, the first end of each of the first fin and the second fin is spaced apart from the inlet end by a predetermined distance.

[0014] According to an embodiment of the present application, the second end of each of the first fin and the second fin is aligned with the outlet end.

[0015] According to an embodiment of the present application, a surface of each of the first and second fins facing the inlet end is a smooth surface.

[0016] According to another aspect of the present application, there is provided a fuel cell system comprising: an electrical stack comprising a plurality of cell units arranged side by side, a gas passage being provided within the electrical stack such that a gas mixed with liquid water is supplied from a first side of the gas passage into the plurality of cell units; wherein the fuel cell system further comprises a gas guiding member as described above, the gas guiding member being configured to guide the gas into the electrical stack.

[0017] The gas guiding member presented by the present application can guide the gas mixed with liquid water towards a side of the gas passage of the electrical stack that is further away from the gas inlet of the cell units, which can cause a portion of the liquid water to be dispersed into more cell units that are further away from the gas passage inlet, thereby reducing the amount of water entering one or more cell units that are closer to the gas passage inlet, so that the amount of water entering each cell unit does not exceed a threshold value, thereby avoiding a "flooding" phenomenon in the electrical stack. BRIEF DESCRIPTION OF DRAWINGS

[0018] Exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. It is to be understood that the embodiments described below are merely exemplary of the present application, and are not intended to limit the scope of the present application, and that the present application should only be limited by the claims. In the drawings:

[0019] Figure 1 is a schematic block diagram of a fuel cell system according to an embodiment of the present application;

[0020] Figure 2 is a schematic perspective view of the gas guiding member shown in Figure 1

[0021] Figure 3 is a schematic perspective view of the gas guiding member shown in Figure 1

[0022] Figures 4A to 4E are schematic front view, cross-sectional view taken along line A-A, left side view, bottom view and top view of the gas guiding member shown in Figure 1

[0023] Figure 5 is a schematic partial cross-sectional view of the gas guiding member and the electrical stack shown in Figure 1 DETAILED DESCRIPTION

[0024] ​​​​The preferred embodiments of the present application will be described in detail below with reference to examples. It should be understood by those skilled in the art that the examples are not intended to mean any limitation to the present application. In addition, the features in the embodiments of the present application can be combined with each other without conflict. In different drawings, the same components are denoted by the same reference numerals, and other components are omitted for simplicity, but this does not mean that the gas guiding member and the fuel cell system of the present application cannot include other components and / or modules. It should be understood that the size, proportional relationship, and number of components in the drawings are not limiting to the present application.

[0025] The fuel cell system of the present application will be described below with reference to Figure 1 As shown in Figure 1 , the fuel cell system 100 includes a stack 60 and a gas guiding member 50, wherein the gas guiding member 50 is configured to guide a gas mixed with liquid water into the stack 60. In the case of the fuel cell system 100 being a PEMFC system, the gas guiding member 50 is provided at the connection of a hydrogen gas inlet pipe (not shown) and the stack 60.

[0026] As shown in Figure 5 , the fuel cell system 100 further includes a gas tank 10 for storing a gas (e.g. a fuel gas such as hydrogen), and the gas enters the stack 60 via a pressure reducing valve 20, an ejector 30, an ejector pump 40, and the gas guiding member 50. As shown in Figure 5 , the stack 60 includes a plurality of cell units 61 (only one is shown in Figure 5 ) arranged side by side, and the stack 60 is provided with a gas passage 62 such that the gas entering the stack 60 is supplied into the plurality of cell units 61 from a first side of the gas passage 62. The first side of the gas passage 62 refers to the side of the gas passage 62 provided with ports communicating with the gas inlets of the plurality of cell units 61. For example, in Figure 5 , the first side of the gas passage 62 is shown as the lower side. It should be noted that for simplicity, only the reaction space of the cell unit 61 receiving the fuel gas is schematically shown in Figure 1 , but the reaction space receiving the oxidizing gas and the sealing and insulation structure between the individual cell units 61 are not shown. However, for those skilled in the art, the stack 60 can adopt various structures existing in the art, and does not affect the understanding and implementation of the technical solutions of the present application, so the stack 60 will not be described in further detail herein.

[0027] Within each cell unit 61, a part of the gas participates in the reaction and generates liquid water, and the gas not participating in the reaction and the generated liquid water are discharged from the stack 60 via an exhaust pipe (not shown). As shown in Figure 1As shown, the fuel cell system 100 can further include a water separator 80 to remove liquid water mixed in the gas discharged from the exhaust pipe, and the separated liquid water can be discharged from a drain valve 90. In addition, the fuel cell system 100 can further include a circulation pump 70, through which the water-separated gas enters the injection pump 40 and then enters the stack 60 again. However, for example, during dynamic operation, due to the reduced efficiency of the water separator 80, some liquid water can still be contained in the water-separated gas, which will also enter the stack 60 again through the circulation pump 70. Moreover, since the temperature downstream of the water separator 80 is generally lower than the temperature upstream of the water separator 80, some water vapor can also condense into liquid water downstream of the water separator 80, which will also enter the stack 60 again with the circulation of the gas. It should be noted that, for the sake of simplicity, only the fuel gas supply device and the pipeline for supplying the fuel gas to the stack 60 are shown in Figures 2 to 5 the drawings, and the oxidizing gas supply device and the pipeline for supplying the oxidizing gas to the stack 60 are not shown, but various existing oxygen supply devices and pipelines for supplying the oxidizing gas to the stack can be used by those skilled in the art, and therefore further detailed description thereof will not be given herein.

[0028] The inventors of the present application have found that, in the absence of the gas guiding member 50 of the present application, these liquid waters will more easily enter one or more cell units 61 closer to the inlet of the gas passage 62 due to gravity. When the amount of liquid water entering these cell units 61 exceeds a threshold value, more reaction gas passages are blocked by the liquid water, resulting in a "water flooding" phenomenon, which leads to the performance degradation of the stack 60. Therefore, the present application proposes a gas guiding member 50 for guiding the gas mixed with liquid water into the stack 60 of the fuel cell system 100.

[0029] The gas guiding member 50 of the present application will be described in detail below with reference to Figure 2 The gas guiding member 50 of the present application will be described in detail below with reference to Figure 3 is a schematic perspective view of the gas guiding member 50, Figure 4A is a schematic cross-sectional perspective view of the gas guiding member 50, Figure 4B is a front view of the gas guiding member 50, Figure 4A is a cross-sectional view taken along line A-A in Figure 4C is a cross-sectional view taken along line A-A in Figure 4D is a left view of the gas guiding member 50, Figure 4E is a bottom view of the gas guiding member 50, Figure 5 is a top view of the gas guiding member 50, Figures 2 to 4E is a partial cross-sectional view of the gas guiding member 50 and the stack 60 assembled together.

[0030] As shown in Figure 2As shown, the gas guiding member 50 includes a body 53, a first fin 51, and a second fin 52. The body 53 has an inlet end (shown as a lower end in Figure 3 and Figure 2 ) and an outlet end (shown as an upper end in Figure 3 and Figure 5 ), and an inner surface of the body 53 (e.g., cylindrical) defines a guiding passage 54 through the body 53. The guiding passage 54 allows gas (e.g., hydrogen mixed with liquid water) to flow in from the inlet end and out from the outlet end. As shown in Figure 4A , the outlet end of the body 53 is configured to be attached with the stack 60 so that the guiding passage 54 is in communication with a gas passage 62 of the stack 60. In addition, the stack 60 can also include an end plate 63 provided with a gas port, and the gas guiding member 50 can be configured to be connected with the end plate 63, i.e., the outlet end of the body 53 is connected with the end plate 63 so that the guiding passage 54 of the gas guiding member 50 can be in communication with the gas passage 62 of the stack 60 through the gas port of the end plate 63.

[0031] As shown in Figure 4D , Figure 4E , and Figure 4A , the first fin 51 and the second fin 52 are symmetrically attached on the inner surface of the body 53 so that the gas entering the guiding passage 54 is symmetrically guided. It is noted that the first fin 51 and the second fin 52 are shown in dashed lines in Figure 4C and Figure 5 . Each of the first fin 51 and the second fin 52 has a first end proximate to the inlet end of the body 53 and a second end proximate to the outlet end of the body 53. Each of the first fin 51 and the second fin 52 can extend helically in opposite helical directions from the respective first end toward the respective second end at a set helical angle. In this way, from the respective first end of the first fin 51 and the second fin 52, two helical surfaces are formed that guide the gas in the helical directions, so that the gas can be guided along the first fin 51 and the second fin 52 to a second side of the gas passage 62 opposite to the first side (i.e., the side of the gas passage 62 away from the gas inlet of the cell units 61), as shown in Figure 5 . In the fuel cell system 100 including the gas guiding member 50 described above, as the gas flows toward the second side of the gas passage 62, the liquid water mixed in the gas can be brought to the cell units 61 further away from the inlet of the gas passage 62 more, thereby reducing the amount of water entering one or more cell units 61 closer to the inlet of the gas passage 61. In this way, compared to the existing fuel cell system, the liquid water can be more evenly spread into more cell units 61, as shown by the downward fine arrows in Figure 2 , so that the amount of liquid water entering each cell unit 61 can be ensured not to exceed a threshold value, and thus the “flooding” phenomenon can be prevented from occurring in the stack 60.

[0032] It should be noted that, herein, "helix angle" has the meaning commonly used in the art, i.e. it refers to the included angle between the tangent of the helix line defined by the first fin 51 and the second fin 52, respectively, and the straight generatrix of the inner surface of the body 53, which is parallel to the longitudinal axis of the body 53. The helix angle of the first fin 51 and the second fin 52 determines the angle at which the gas is directed, and can be designed in accordance with parameters such as the longitudinal length, the diameter of the guiding channel 54, and the gas pressure. To achieve the desired guidance and to avoid too much disturbance to the gas, the helix angle can preferably be in the range of 30 degrees to 60 degrees.

[0033] As shown in Figure 3 , Figure 4A , Figure 4D , Figure 4E and Figure 3 , the first end of the first fin 51 and the first end of the second fin 52 can be connected to each other, e.g. forming a ridge 55. The ridge 55 can more effectively direct the gas entering the guiding channel 54 towards both sides, so that the gas flows along the gas-facing surfaces of the first fin 51 and the second fin 52 towards the second side of the gas passage 62. It should be noted that the first end of the first fin 51 and the first end of the second fin 52 can also not be connected, e.g. abut against each other, still achieving the desired guidance.

[0034] As shown in Figure 4A , Figure 4D , Figure 4E and Figure 4D , the second end of the first fin 51 and the second end of the second fin 52 can be spaced apart from each other, so that the gas can pass through the gap between the second end of the first fin 51 and the second end of the second fin 52 to the second side of the gas passage 62 unhindered. Preferably, the distance d (see Figure 3 ) between the second end of the first fin 51 and the second end of the second fin 52 can be less than 70% of the diameter of the guiding channel 54. When the distance d is too large, the gas is dispersed to a wider area and can cause the guiding effect of the gas guiding member 50 to weaken.

[0035] As shown in Figure 4D , Figure 4E and Figure 4DAs shown, according to another embodiment, in order to more effectively guide the gas, the height h of each of the first and second fins 51 and 52 can gradually decrease from the respective first end towards the respective second end. In this way, the gas can be diffused into the battery cell 61 further away from the inlet of the gas passage 62 in a gradually smooth flow state during the process of flowing towards the second side of the gas passage 62. According to another embodiment of the present application, in the case where the height of the second end of each of the first and second fins 51 and 52 decreases to 0, the second end of the first fin 51 can meet the second end of the second fin 52 at a point, still being able to play the desired guiding role. It should be pointed out that the height h above refers to the height of the inner edge of each fin in the radial direction relative to the inner surface of the body 53, as shown in Figure 2 .

[0036] Preferably, the height h of each of the first and second fins 51 and 52 at the respective first end can be in the range of 30% to 50% of the diameter of the guiding passage 54. In this way, the first and second fins 51 and 52 avoid causing excessive obstruction to the gas while providing the desired gas guiding.

[0037] As shown in Figure 3 , Figures 4A to 4C , Figure 3 The first end of each of the first and second fins 51 and 52 can be spaced apart from the inlet end by a predetermined distance. In this way, in the case where the gas inlet pipe is connected in an inclined manner to the gas guiding member 50, maintaining the predetermined distance between the first ends of the two fins and the inlet end of the body 53 can cause the gas to be guided over the predetermined distance in order to slow down the flow disturbance caused by the inclined connection, ensuring that the gas entering the guiding passage 54 is smoothly and effectively guided.

[0038] As shown in Figures 4A to 4C , Figure 5 The second end of each of the first and second fins 51 and 52 can be aligned with the outlet end, thereby shortening the path of the gas guided through the first and second fins 51 and 52 to reach the gas passage 62, achieving efficient guiding.

[0039] In order to smoothly guide the gas, the surface of each of the first and second fins 51 and 52 facing the inlet end can be a smooth surface. Since the surface of each of the first and second fins 51 and 52 facing the outlet end usually has a weaker effect on the gas flow, the shape thereof can not be limited.

[0040] For ease of processing, the cross-section of each of the first fin 51 and the second fin 52 can be approximately rectangular. It should be noted that this application does not limit the material or manufacturing process of the gas guiding member 50. For example, the body 53 of the gas guiding member 50 and the first fin 51 and the second fin 52 can be made of the same or different metals, plastics, or composite materials through processes such as machining, casting, injection molding, welding, and bonding.

[0041] The following reference Figure 5 To further explain the role of the gas guiding component 50 in the operation of the fuel cell system 100, as described in this application. Figure 5 As shown, when the gas mixed with liquid water enters the gas guiding member 50 as indicated by the thick arrow, the gas is guided by the first fin 51 and the second fin 52 in opposite spiral directions to the second side of the gas channel 62. Figure 5 (As shown above the gas inlet away from battery cell 61). Because the gas is guided to the second side of the gas channel 62, the liquid water mixed in the gas can diffuse into battery cells 61 farther from the inlet of the gas channel 62, rather than entering more of the battery cells 61 closer to the inlet of the gas channel 62. This allows the liquid water to diffuse more evenly into more battery cells 61, such as... ​ As indicated by the thin downward arrow in the diagram. Allowing some liquid water to diffuse into the battery cells 61 further from the inlet of the gas channel 62 reduces the amount of water entering one or more batteries 61 closer to the inlet of the gas channel 62, keeping it below the threshold that causes "flooding." In this case, compared to the prior art without the gas guiding member 50, although the gas guiding member 50 increases the amount of water in the battery cells 61 further from the inlet of the gas channel 62, it does not cause it to exceed the threshold. Therefore, it can be ensured that the amount of water in all battery cells 61 does not exceed the threshold, thus preventing "flooding" within the stack 60.

[0042] According to the above embodiments of this application, by providing a gas guiding component, the amount of liquid water entering one or more battery cells closer to the gas channel inlet of the fuel cell stack can be reduced, thereby avoiding "flooding" in the fuel cell stack. Furthermore, the gas guiding component of this application has a simple structure and can be used to modify the gas pipelines of existing fuel cell systems.

[0043] The present application has been described in detail above with reference to specific embodiments. Obviously, the above description and the embodiments shown in the accompanying drawings should be understood as exemplary and not as limiting the present application. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and such modifications or alterations do not depart from the scope of the present application.

Claims

1. A gas guiding member (50) for guiding a gas mixed with liquid water into a fuel cell stack (60) of a fuel cell system (100), the stack (60) comprising a plurality of battery cells (61) arranged side by side, the stack (60) having a gas passage (62) therein such that the gas is supplied from a first side of the gas passage (62) to the plurality of battery cells (61), characterized in that, The gas guiding component (50) includes: A body (53) having an inlet end and an outlet end, the inner surface of the body (53) defining a guide channel (54) extending through the body (53), the outlet end of the body (53) being configured for attachment to the fuel cell stack (60) such that the guide channel (54) communicates with the gas passage (62); and A first fin (51) and a second fin (52) are symmetrically attached to the inner surface of the body (53). Each of the first fin (51) and the second fin (52) has a first end near the inlet end and a second end near the outlet end. Each of the first fin (51) and the second fin (52) extends spirally from their respective first ends toward their respective second ends at a set spiral angle in opposite spiral directions, such that the gas is guided along the first fin (51) and the second fin (52) to the second side of the gas passage (62) opposite to the first side.

2. The gas guiding component (50) according to claim 1, characterized in that, The helix angle is in the range of 30 to 60 degrees.

3. The gas guiding member (50) according to claim 1 or 2, characterized in that, The first end of the first fin (51) and the first end of the second fin (52) are connected to each other to form a ridge (55).

4. The gas guiding member (50) according to claim 1 or 2, characterized in that, The distance (d) between the second end of the first fin (51) and the second end of the second fin (52) is less than 70% of the diameter of the guide channel (54).

5. The gas guiding member (50) according to claim 1 or 2, characterized in that, The height (h) of each of the first fin (51) and the second fin (52) gradually decreases from their respective first ends toward their respective second ends.

6. The gas guiding member (50) according to claim 5, characterized in that, The height (h) of each of the first fin (51) and the second fin (52) at their respective first ends is in the range of 30% to 50% of the diameter of the guide channel (54).

7. The gas guiding member (50) according to claim 1 or 2, characterized in that, The first end of each of the first fin (51) and the second fin (52) is spaced apart from the inlet end by a predetermined distance.

8. The gas guiding member (50) according to claim 1 or 2, characterized in that, The second end of each of the first fin (51) and the second fin (52) is aligned with the outlet end.

9. The gas guiding member (50) according to claim 1 or 2, characterized in that, The surface of each of the first fin (51) and the second fin (52) facing the inlet end is a smooth surface.

10. A fuel cell system (100), comprising: A battery stack (60) comprising a plurality of battery cells (61) arranged side by side, wherein a gas passage (62) is provided in the battery stack (60) such that a gas mixed with liquid water is supplied from a first side of the gas passage (62) to the plurality of battery cells (61); The fuel cell system (100) is characterized in that it further includes a gas guiding member (50) according to any one of claims 1 to 9, the gas guiding member (50) being configured to guide the gas into the fuel cell stack (60).

Images