Gas guiding member and fuel cell system

Abstract

The utility model provides a gas guiding component which is used for guiding gas mixed with liquid water into an electric pile of a fuel cell system. A gas channel is arranged in the electric pile, so that gas is supplied into the plurality of battery units from a first side of the gas channel. The gas guide member comprises: a body having an inlet end and an outlet end for attachment with a stack, an inner surface of the body defining a guide channel through the body, at least one set of grooves formed on the inner surface of the body, each set comprising a first groove and a second groove symmetrical to each other, each groove has a first end proximate the inlet end and a second end proximate the outlet end, and each groove extends helically from a respective first end toward a respective second end at a set helix angle in an opposite helix direction such that gas is directed along the groove 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 member. 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, wherein at least one set of grooves is formed on the inner surface of the body, each of the at least one set of grooves comprising a first groove and a second groove, the first groove and the second groove being symmetrical to each other, each of the first groove and the second groove having a first end proximate to the inlet end and a second end proximate to the outlet end, and each of the first groove and the second groove spirally extends in opposite spiral directions at a set helix angle from the respective first end towards the respective second end, such that the gas is guided along the first groove and the second groove to a second side of the gas passage opposite to the first side.

[0008] According to an embodiment of the present application, the helix 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 groove and the first end of the second groove are connected to each other to form a first notched portion.

[0010] According to an embodiment of the present application, the second end of the first groove and the second end of the second groove are connected to each other to form a second notched portion.

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

[0012] According to an embodiment of the present application, the depth of each of the first groove and the second groove at the respective first end is in the range of 30% to 60% of the wall thickness of the body.

[0013] According to an embodiment of the present application, a portion of the groove surface of each of the first groove and the second groove facing the inlet end is a smooth surface.

[0014] According to an embodiment of the present application, the at least one set of grooves comprises a plurality of sets of grooves arranged at the same azimuth along the longitudinal axis of the gas guiding member, wherein two adjacent sets of grooves partially overlap.

[0015] According to an embodiment of the present application, a first end of each of a first groove and a second groove in a first set of grooves of the plurality of sets of grooves closest to the inlet end is aligned with the inlet end, and a second end of each of a first groove and a second groove in a last set of grooves of the plurality of sets of grooves closest to the outlet end is aligned with the outlet end.

[0016] According to another aspect of the present application, there is provided a fuel cell system comprising an electric stack comprising a plurality of cell units arranged side by side, a gas passage being provided within the electric 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 the gas guiding member as described above, which is configured to guide the gas into the electric stack.

[0017] The gas guiding member according to the present application can guide the gas mixed with liquid water towards a side of the gas passage of the electric stack 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 further away from the gas passage inlet, thereby reducing the amount of water entering one or more cell units 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 electric 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 given by way of explanation of the present application, but not intended to limit the scope of the present application, and that the present application is applicable to other embodiments.

[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 Figure 1 is a front view of the gas guiding member shown in

[0021] Figure 3 is a schematic cross-sectional perspective view of the gas guiding member taken along Figure 2 line A-A shown in

[0022] Figure 4 is a left view of the gas guiding member shown in Figure 2 schematically illustrating

[0023] Figure 5 is a right view schematically showing Figure 2 the gas guiding member shown in

[0024] Figure 6 is a right view schematically showing Figure 1 the gas guiding member and the stack shown in DETAILED DESCRIPTION

[0025] The preferred embodiments of the present application will be described in detail below with examples. It should be understood by those skilled in the art that the examples do not mean to form any limitation on 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 intended to limit the present application.

[0026] 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 where the fuel cell system 100 is 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.

[0027] As shown in Figure 1 , the fuel cell system 100 further includes a gas tank 10 for storing a gas (e.g., a fuel gas such as hydrogen gas), 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 6 , the stack 60 includes a plurality of cell units 61 (only one is shown in Figure 6 ) 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 a port communicating with the gas inlets of the plurality of cell units 61. For example, in Figure 6 , the first side of the gas passage 62 is shown as the lower side. It should be noted that, for simplicity, in Figure 6The figure only schematically shows the reaction space of the battery cell 61 for receiving the fuel gas, but does not show the reaction space for receiving the oxidizing gas, nor does it show the sealing and insulation structures between the battery cells 61. However, for those skilled in the art, the battery stack 60 can adopt various existing structures in the art without affecting the understanding and implementation of the technical solutions of the present application. Therefore, the battery stack 60 will not be described in further detail herein.

[0028] In each battery cell 61, a portion of the gas participates in the reaction and generates liquid water, and the gas that does not participate in the reaction and the generated liquid water are discharged from the battery stack 60 through an exhaust pipe (not shown). Figure 1 As shown, the fuel cell system 100 may further include a water separator 80 to remove liquid water mixed in the gas discharged from the exhaust pipe, and the separated liquid water may be discharged from the drain valve 90. In addition, the fuel cell system 100 may further include a circulation pump 70, and the gas that has undergone water separation enters the jet pump 40 through the circulation pump 70 and enters the fuel cell stack 60 again. However, for example, during dynamic operation, since the efficiency of the water separator 80 may decrease, the gas that has undergone water separation may still contain some liquid water, and this liquid water will also enter the fuel cell 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 may also condense into liquid water downstream of the water separator 80, and this condensed liquid water will also enter the fuel cell stack 60 again as the gas circulates. It should be noted that for the sake of simplicity, in Figure 1 Only the fuel gas supply device and pipeline for supplying fuel gas to the fuel cell stack 60 are shown, while the oxidizing gas supply device and pipeline for supplying oxidizing gas to the fuel cell stack 60 are not shown. However, for those skilled in the art, a variety of existing oxygen supply devices and pipelines for supplying oxidizing gas to the fuel cell stack can be used, so this article will not describe this in further detail.

[0029] The inventors of this application have discovered that without the gas guiding member 50 of this application, this liquid water would, due to gravity, enter more of one or more battery cells 61 near the entrance of the gas channel 62. When the amount of liquid water entering these battery cells 61 exceeds a threshold, a large number of reactant gas channels are blocked by liquid water, resulting in "flooding", which in turn reduces the performance of the fuel cell stack 60. To this end, this application proposes a gas guiding member 50 for guiding gas mixed with liquid water into the fuel cell stack 60 of the fuel cell system 100.

[0030] Refer to the following Figures 2 to 6 The gas guide member 50 of the present application will be described in detail. Figure 2 is a schematic front view of the gas guide member 50 (with the internal structure shown in dotted lines), Figure 3 It is alongFigure 2 A schematic cross-sectional perspective view of the gas guide member 50 taken along line AA in FIG. Figure 4 is a left side view of the gas guide member 50, Figure 5 is a right side view of the gas guide member 50, Figure 6 FIG. 5 is a partial cross-sectional view of the gas guide member 50 and the fuel cell stack 60 assembled together.

[0031] like Figures 2 to 5 As shown, the gas guide member 50 includes a body 53, and a plurality of grooves ( Figure 2 、 Figure 3 and Figure 6 4 groups are shown in FIG), wherein each group of grooves includes a first groove 51 and a second groove 52. The body 53 has an inlet end (at Figure 2 、 Figure 3 and Figure 6 The left end is shown in the figure) and the outlet end (in Figure 2 、 Figure 3 and Figure 6 The inner surface of the body 53 defines a guide channel 54 that passes through the body 53. The guide channel 54 allows gas (for example, hydrogen mixed with liquid water) to flow in from the inlet end and out from the outlet end. Figure 6 As shown, the outlet end of the body 53 is configured to be attached to the fuel cell stack 60 so that the guide channel 54 communicates with the gas channel 62. In addition, the fuel cell stack 60 may further include an end plate 63 having a gas port. The gas guide member 50 may be configured to be connected to the end plate 63, that is, the outlet end of the body 53 is connected to the end plate 63 so that the guide channel 54 of the gas guide member 50 can communicate with the gas channel 62 of the fuel cell stack 60 through the gas port of the end plate 63.

[0032] like Figures 2 to 5 As shown, the first groove 51 and the second groove 52 in each group of grooves are symmetrical to each other, so that the gas entering the guide channel 54 is guided symmetrically. Figure 2 4 groups of first grooves 51 and second grooves 52 are shown in dotted lines. Each of the first grooves 51 and the second grooves 52 has a first end close to the inlet end of the body 53 and a second end close to the outlet end of the body 53. Each of the first grooves 51 and the second grooves 52 can extend spirally in opposite spiral directions at a set spiral angle from the respective first end toward the respective second end. In this way, starting from the respective first ends of the first grooves 51 and the second grooves, two left and right spiral groove surfaces for guiding gas in a spiral direction are formed, so that the gas can be guided along the first grooves 51 and the second grooves 52 to the second side of the gas channel 62 opposite to the first side (that is, the side of the gas channel 62 away from the gas inlet of the battery cell 61), as shown in FIG. Figure 6As shown. 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 the cell unit(s) 61 closer to the inlet of the gas passage 61. In this way, compared with the prior 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 6 , thereby ensuring that the amount of liquid water entering each cell unit 61 does not exceed the threshold value, and thus the "flooding" phenomenon does not occur in the stack 60.

[0033] It should be noted that, herein, the "helix angle" has the meaning commonly used in the art, i.e. refers to the included angle between the tangent of the helix line defined by the first groove 51 and the second groove 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 groove 51 and the second groove 52 determines the angle at which the gas is guided, and can be designed according to the longitudinal length, diameter of the guiding passage 54, the number of grooves, and the gas pressure, etc. To achieve the desired guidance and avoid excessive interference to the gas, the helix angle can preferably be in the range of 30 degrees to 60 degrees.

[0034] As shown in Figures 2 to 5 , the first end of the first groove 51 and the first end of the second groove 52 can be connected to each other, for example, forming a first notched portion 55. The first notched portion 55 can more effectively guide the gas entering the guiding passage 54 toward the two sides, so that the gas flows along the gas-facing groove surfaces of the first groove 51 and the second groove 52 toward the second side of the gas passage 62.

[0035] As shown in Figures 2 to 5 , the second end of the first groove 51 and the second end of the second groove 52 can be connected to each other to form a second notched portion (not labeled), so that the gas can converge together from the second end of the first groove 51 and the second end of the second groove 52, guiding the gas to flow toward the second side of the gas passage 62.

[0036] As shown in Figures 3 to 5As shown, according to another embodiment, the depth d of each of the first and second grooves 51 and 52 can gradually decrease from the respective first end toward the respective second end in order to more effectively guide the gas. 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 flow toward the second side of the gas passage 62. According to another embodiment of the present application, in the case where the depth of the second end of each of the first and second grooves 51 and 52 is reduced to 0, the second end of the first groove 51 can be merged with the second end of the second groove 52 at a point (e.g., a point P shown in FIG. 6) as shown in FIG. 7. It is noted that the depth d described above refers to the depth of the bottom of the groove in the radial direction with respect to the inner surface of the body 53 as shown in FIG. 8. Figures 2 to 5 Figure 3

[0037] Preferably, the depth d of each of the first and second grooves 51 and 52 at the respective first end can be in the range of 30% to 60% of the wall thickness of the body 53. In this way, the first and second grooves 51 and 52 can maintain the strength of the body 53 while providing the desired gas guidance.

[0038] In order to smoothly guide the gas, the portion of the groove surface of each of the first and second grooves 51 and 52 facing the inlet end can be a smooth surface. Since the portion of the groove surface of each of the first and second grooves 51 and 52 facing the outlet end generally has a weak effect on the gas flow, the shape thereof can not be limited. For example, the cross-sectional shape of each of the first and second grooves 51 and 52 can be an asymmetric shape such that the slope of the portion of the groove surface of each groove facing the inlet end is smaller than the slope of the portion of the groove surface facing the outlet end, so that most of the groove surface of each groove is used to guide the gas in the desired manner.

[0039] Figure 2 Figure 3 Figure 6 ​​​​​As shown, four groups of grooves are arranged in the same orientation along the longitudinal axis of the gas guiding member 50, with adjacent groups of grooves partially overlapping. This allows the gas to be guided multiple times, ensuring efficient gas guidance to the second side of the gas channel 62. In the four groups of grooves shown, the first end of each of the first groove 51 and second groove 52 in the first group of grooves closest to the inlet end is aligned with the inlet end, and the second end of each of the first groove 51 and second groove 52 in the last group of grooves closest to the outlet end is aligned with the outlet end. In this manner, gas entering the guide channel 54 can smoothly enter the first ends of the first grooves 51 and second grooves 52 in the first group of grooves and smoothly exit from the second ends of the first grooves 51 and second grooves 52 in the last group of grooves, achieving efficient gas guidance.

[0040] It should be noted that although in this application Figures 2 to 6 , the gas guiding member 50 is shown to include four groups of grooves, but the present application is not limited thereto, and may include fewer or more groups of grooves. For example, according to another embodiment of the present application, the gas guiding member 50 may include only one group of grooves. In this case, the first ends of the first groove 51 and the second groove 52 are aligned with the inlet end of the body 53, and the second ends of the first groove 51 and the second groove 52 are aligned with the outlet end of the body 53, and the gas can still be smoothly guided to the second side of the gas channel 62. However, the inventors of the present application have found that since the grooves formed on the inner surface of the body 53 are recessed, the recessed grooves have limited guiding effect on the gas. Therefore, when stronger guidance is required, multiple groups of grooves can be provided according to parameters such as the longitudinal length, diameter, and gas pressure of the guide channel 54.

[0041] It should be noted that the present application does not limit the material and manufacturing process of the gas guiding member 50. For example, the gas guiding member 50 can be made of metal, plastic or composite materials through machining, casting, injection molding and other processes.

[0042] Refer to the following Figure 6 To further explain the role of the gas guide member 50 of the present application in the operation of the fuel cell system 100. Figure 6 As shown, when the gas mixed with liquid water enters the gas guide member 50 as shown by the thick arrow, the gas is guided to the second side of the gas channel 62 ( FIG. 5 ) by the first groove 51 and the second groove 52 in each group of grooves in opposite spiral directions. Figure 6 ). It should be noted that in Figure 6The gas in the trenches behind the first group of trenches is also shown, as indicated by the fine arrows below the coarse arrow. Since the gas is directed to the second side of the gas channel 62, the liquid water mixed in the gas can be diffused into the cell units 61 further away from the inlet of the gas channel 62, instead of first entering one or more cell units 61 closer to the inlet of the gas channel 62. This can make the liquid water more evenly diffuse into more cell units 61, as indicated by the downward fine arrows in Figure 6 Diffusing some liquid water into the cell units 61 further away from the inlet of the gas channel 62 can reduce the amount of water entering one or more cell units 61 closer to the inlet of the gas channel 62 below the threshold value that causes the "flooding" phenomenon. In this case, although the gas directing member 50 increases the amount of water in the cell units 61 further away from the inlet of the gas channel 62, it does not exceed the threshold value, compared with the prior art without the gas directing member 50. Therefore, the amount of water in all the cell units 61 can be guaranteed not to exceed the threshold value, and thus the "flooding" phenomenon in the stack 60 can be avoided.

[0043] According to the above embodiments of the present application, by providing the gas directing member, the amount of liquid water entering one or more cell units closer to the inlet of the gas channel of the stack can be reduced, so that the "flooding" phenomenon in the stack can be avoided. In addition, the gas directing member of the present application has a simple structure, and can be used to retrofit the gas pipe of an existing fuel cell system.

[0044] The above description of the present application has been made in conjunction with specific embodiments. It is obvious that the above description and the embodiments shown in the drawings should be understood as exemplary, and do not constitute a limitation on the present application. Various modifications or changes can be made to the present application without departing from the spirit of the present application, and these modifications or changes 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 an electrical stack (60) of a fuel cell system (100), the electrical stack (60) comprising a plurality of cell units (61) arranged side by side, a gas channel (62) being provided within the electrical stack (60) such that the gas is supplied into the plurality of cell units (61) from a first side of the gas channel (62), characterized in that, The gas guiding member (50) comprises: a body (53) having an inlet end and an outlet end, an inner surface of the body (53) defining a guiding channel (54) through the body (53), the outlet end of the body (53) being configured for attachment with the stack (60) to make the guiding channel (54) communicate with the gas channel (62), wherein at least one set of grooves is formed on the inner surface of the body (53), each of the at least one set of grooves comprises a first groove (51) and a second groove (52), the first groove (51) and the second groove (52) are symmetrical to each other, each of the first groove (51) and the second groove (52) has a first end close to the inlet end and a second end close to the outlet end, and each of the first groove (51) and the second groove (52) spirally extends in opposite spiral directions at a set spiral angle from the respective first end towards the respective second end, so that the gas is guided along the first groove (51) and the second groove (52) to a second side of the gas channel (62) opposite to the first side.

2. Gas guiding member (50) according to claim 1, characterized in that The spiral angle is in a range of 30 degrees to 60 degrees.

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

4. Gas guiding member (50) according to claim 1 or 2, characterized in that The second end of the first groove (51) and the second end of the second groove (52) are connected with each other to form a second notched portion.

5. Gas guiding member (50) according to claim 1 or 2, characterized in that The depth (d) of each of the first groove (51) and the second groove (52) gradually decreases from the respective first end towards the respective second end.

6. Gas guiding member (50) according to claim 5, characterized in that The depth (d) of each of the first groove (51) and the second groove (52) at the respective first end is in a range of 30% to 60% of a wall thickness of the body (53).

7. Gas guiding member (50) according to claim 1 or 2, characterized in that A portion of groove surface of each of the first groove (51) and the second groove (52) facing the inlet end is a smooth surface.

8. Gas guiding member (50) according to claim 1 or 2, characterized in that The at least one set of grooves comprises a plurality of sets of grooves, the plurality of sets of grooves are arranged in the same orientation along a longitudinal axis of the gas guiding member (50), wherein two adjacent sets of grooves partially overlap.

9. Gas guiding member (50) according to claim 8, characterized in that The first end of each of the first groove (51) and the second groove (52) in a first set of grooves of the plurality of sets of grooves closest to the inlet end is aligned with the inlet end, and the second end of each of the first groove (51) and the second groove (52) in a last set of grooves of the plurality of sets of grooves closest to the outlet end is aligned with the outlet end.

10. A fuel cell system (100) comprising: a stack (60) comprising a plurality of cell units (61) arranged side by side, a gas channel (62) is provided in the stack (60) so that a gas mixed with liquid water is supplied from a first side of the gas channel (62) into the plurality of cell units (61); characterized in that the fuel cell system (100) further comprises a gas guiding member (50) according to any one of claims 1 to 9, the gas guiding member (50) being configured for guiding the gas into the stack (60).

Images