Fuel cell stack

Abstract

The application provides a fuel cell stack, comprising: a cell assembly, which comprises a plurality of single cells arranged at intervals along a first direction, one side of each single cell is provided with a cell flow channel, and a first gas inlet and a first gas outlet, which are in communication with the cell flow channel, are arranged at intervals on each single cell to form a gas inlet flow channel and a gas outlet flow channel of the fuel cell stack respectively; two end plates, which are arranged at intervals along the first direction on opposite sides of the cell assembly, a second gas inlet and a second gas outlet, which are arranged at intervals on one end plate, are used to communicate with the gas inlet flow channel and the gas outlet flow channel respectively; and a baffle, one end of which is connected with a hole wall surface of the second gas inlet, and the other end of which is used to be inserted at an inlet of the gas inlet flow channel, and the baffle is located on a side of the cell flow channel far away from the gas inlet flow channel, so that the problem that the gas flow in the cell flow channel close to the inlet end of the fuel cell stack in the prior art is small is solved, and the cold start performance of the fuel cell stack is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, in particular to a fuel cell stack. BACKGROUND

[0002] For a general fuel cell stack, its internal flow field is composed of a plurality of identical double single cells, which leads to that the distribution of its reactants (air / oxygen, hydrogen) can be approximately equivalent to a straight channel cross-section air supply system.

[0003] Past researches show that, during the cold start process of the stack, the outermost cells (especially the cells near the gas inlet side) are more likely to fail than the cells in the middle part.

[0004] This is because, on the one hand, the outer cells are close to the end plate, and the heat dissipation to the outside through the end plate is more; on the other hand, without external heating, the gas temperature at the inlet is the lowest, and the heat exchange with the cells is the most.

[0005] By increasing the flow of reactants (hydrogen, air / oxygen), the current density of the single cells at these positions can be increased, and in turn the heat production is increased, thereby making up for the temperature reduction due to heat exchange with the outside and cold start failure.

[0006] However, the gas pressure (total pressure) in the common flow channel of the fuel cell stack in the prior art is divided into dynamic pressure and static pressure, wherein the dynamic pressure is consistent with the direction of gas flow, and the static pressure is perpendicular to the wall of the common flow channel, so in this structure, the main static pressure enters the cell flow channel; and according to the static pressure recovery theory, as the gas flows in the common flow channel and continuously sends out gas to the cell flow channels along the way, its flow rate and dynamic pressure will continuously decrease, and thus its static pressure value continuously increases, that is, the gas flow in the cell flow channel near the inlet end is small, and as the common flow channel of the stack is longer, the above phenomenon will be more obvious. SUMMARY

[0007] The main purpose of the present application is to provide a fuel cell stack to solve the problem that the gas flow in the cell flow channel near the inlet end of the fuel cell stack in the prior art is small.

[0008] In order to achieve the above object, the present application provides a fuel cell stack, comprising: a cell assembly comprising a plurality of single cells arranged at intervals along a first direction, each single cell being provided with a cell flow channel on one side, and each single cell being provided with a first gas inlet hole and a first gas outlet hole arranged at intervals thereon and communicated with the cell flow channel, so as to form a gas inlet flow channel and a gas outlet flow channel of the fuel cell stack respectively; two end plates arranged at intervals along the first direction on opposite sides of the cell assembly, wherein one of the two end plates is provided with a second gas inlet hole and a second gas outlet hole arranged at intervals thereon and communicated with the gas inlet flow channel and the gas outlet flow channel respectively; and a baffle, one end of the baffle being connected with a hole wall surface of the second gas inlet hole, and the other end of the baffle being used for being inserted at an inlet of the gas inlet flow channel, and the baffle being located on a side of the cell flow channel away from the gas inlet flow channel.

[0009] Further, the two end plates are a first end plate and a second end plate, the second gas inlet hole and the second gas outlet hole are located on the first end plate, and the second gas inlet hole and the second gas outlet hole are rectangular holes.

[0010] Further, the baffle comprises a first plate body and a second plate body connected in sequence, the first plate body is perpendicular to the end plate and connected with the first end plate, and the second plate body is parallel to the end plate, the second plate body is located on a side of the first plate body away from the first end plate and on a side of the first plate body close to the cell flow channel.

[0011] Further, the baffle further comprises a third plate body, the third plate body is parallel to the second plate body, the third plate body is connected with the first plate body and located between the second plate body and the first end plate.

[0012] Further, the cell flow channel extends along a second direction perpendicular to a gas flow direction in the gas inlet flow channel, the gas inlet flow channel and the gas outlet flow channel are located at two ends of the cell flow channel respectively, and a width of the third plate body in the second direction is smaller than a width of the second plate body in the second direction.

[0013] Further, the baffle comprises an arc-shaped plate body, the arc-shaped plate body is connected with the first end plate, and a distance between the arc-shaped plate body and the cell flow channel gradually decreases in a direction away from the first end plate.

[0014] Further, the cell flow channel extends along the second direction, the baffle comprises a triangular plate body, the triangular plate body is connected with the first end plate, and a width of the triangular plate body in the second direction gradually increases in a direction away from the first end plate.

[0015] Further, the triangular plate body is a right-angled triangular plate body, a first outer side surface of the right-angled triangular plate body including one right angle side is located on a side of the cell flow channel away from the gas inlet flow channel, and a second outer side surface of the right-angled triangular plate body including another right angle side is arranged at intervals with the first end plate.

[0016] Further, the end plate and the baffle plate are integrally formed or detachably connected; and / or the end plate and the baffle plate are made of the same material.

[0017] Further, the size and shape of the second inlet hole are the same as the size and shape of the first inlet hole on each single cell, and the size and shape of the second outlet hole are the same as the size and shape of the first outlet hole on each single cell.

[0018] According to the technical scheme of the present application, the fuel cell stack comprises: a cell assembly comprising a plurality of single cells arranged at intervals along a first direction, each single cell being provided with a cell flow channel on one side, and each single cell being provided with a first inlet hole and a first outlet hole arranged at intervals and communicating with the cell flow channel, for forming an inlet flow channel and an outlet flow channel of the fuel cell stack, respectively; two end plates arranged at intervals along the first direction on opposite sides of the cell assembly, one of the end plates being provided with a second inlet hole and a second outlet hole arranged at intervals and communicating with the inlet flow channel and the outlet flow channel, respectively; and a baffle plate, one end of the baffle plate being connected to a hole wall surface of the second inlet hole, and the other end of the baffle plate being arranged at an entrance of the inlet flow channel, and the baffle plate being arranged on a side of the cell flow channel away from the inlet flow channel. In this way, by arranging the baffle plate at the second inlet hole of the end plate of the fuel cell stack, when external airflow enters the inlet flow channel, the flow will be hindered by the baffle plate, part of the dynamic pressure is converted into static pressure, so that the static pressure at the position of the baffle plate is increased, and part of the dynamic pressure gas is caused to enter the corresponding cell flow channel due to the change in the direction of the gas flow, so that the flow rate of the gas entering the cell flow channel from the position of the baffle plate is increased, thereby causing the current density generated by the fuel cell stack to increase and the heat generation to increase, and finally improving the cold start performance of the fuel cell stack, and solving the problem of small gas flow rate in the cell flow channel close to the inlet end of the fuel cell stack in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the present application illustrated in the drawings are presented by way of example or for purpose of illustration, and not as limitations of the present application. In the drawings:

[0020] Figure 1 A simplified schematic diagram showing a cross-sectional view of an embodiment of the fuel cell stack according to the present application is shown;

[0021] Figure 2 A simplified schematic diagram showing a cross-sectional view of an embodiment of the fuel cell stack according to the present application is shown; Figure 1 A simplified schematic diagram showing a cross-sectional view of an embodiment of the fuel cell stack according to the present application is shown;

[0022] Figure 3 A simplified schematic diagram showing a cross-sectional view of an embodiment of the fuel cell stack according to the present application is shown; Figure 1 A simplified schematic diagram showing a cross-sectional view of an embodiment of the fuel cell stack according to the present application is shown;

[0023] Figure 4 It shows Figure 1 The diagram shows a first embodiment of the end plates and baffles of the fuel cell stack after assembly.

[0024] Figure 5 It shows Figure 1 The diagram shows a second embodiment of the end plates and baffles of the fuel cell stack after assembly.

[0025] Figure 6 It shows Figure 1 The third embodiment of the fuel cell stack end plates and baffles is shown in a schematic diagram of the assembled structure.

[0026] Figure 7 It shows Figure 1 The diagram shows a fourth embodiment of the fuel cell stack end plates and baffles after assembly.

[0027] The above figures include the following reference numerals:

[0028] 11. Inlet air passage; 12. Outlet air passage; 2. Battery passage; 3. First end plate; 31. Second air inlet; 32. Second air outlet; 4. Single battery; 41. First air inlet; 42. First air outlet; 5. Second end plate; 6. Baffle; 61. First plate; 62. Second plate; 63. Third plate; 64. Arc-shaped plate; 65. Triangular plate. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figures 1 to 7 As shown, the present invention provides a fuel cell stack, comprising: a battery assembly including a plurality of single cells 4 spaced apart along a first direction, each single cell 4 having a battery flow channel 2 on one side, and each single cell 4 having a first air inlet 41 and a first air outlet 42 spaced apart and communicating with the battery flow channel 2, for forming an air inlet channel 11 and an air outlet channel 12 of the fuel cell stack respectively; two end plates spaced apart on opposite sides of the battery assembly along the first direction, one end plate having a second air inlet 31 and a second air outlet 32 ​​spaced apart and communicating with the air inlet channel 11 and the air outlet channel 12 respectively; and a baffle 6, one end of the baffle 6 being connected to the wall of the second air inlet 31, the other end of the baffle 6 being inserted into the inlet of the air inlet channel 11, and the baffle 6 being located on the side of the air inlet channel 11 away from the battery flow channel 2.

[0031] Thus, by setting a baffle 6 at the second air inlet 31 of the end plate of the fuel cell stack, when the external airflow enters the air inlet channel 11, its flow will be hindered by the baffle 6, and part of the dynamic pressure will be converted into static pressure, which will increase the static pressure at the location of the baffle 6. At the same time, due to the change in the gas flow direction at this location, part of the dynamic pressure gas will enter the corresponding battery flow channel 2. Therefore, the flow rate of the gas entering the battery flow channel 2 from the location of the baffle 6 will also increase, which will lead to an increase in the current density and heat generation of the fuel cell stack, and ultimately improve the cold start performance of the fuel cell stack, solving the problem of the small gas flow rate in the battery flow channel near the inlet end of the fuel cell stack in the prior art.

[0032] Currently, existing technologies mainly include two types of flow fields: U-shaped flow fields and Z-shaped flow fields. A U-shaped flow field refers to reactants entering and exiting from the same side, while a Z-shaped flow field refers to reactants entering from one side of the fuel cell stack and exiting from the other side. The fuel cell stack of this invention has a U-shaped flow field structure. In fact, the design principle of this invention is universal for other flow field configurations such as Z-shaped flow fields.

[0033] Among them, the battery flow channel 2 extends along a second direction perpendicular to the gas flow direction in the air intake channel 11, and multiple battery flow channels 2 are provided on the same side of each single battery 4. The multiple battery flow channels 2 are arranged at intervals along a third direction perpendicular to the gas flow direction in the air intake channel 11 and perpendicular to the second direction.

[0034] Optionally, the structure of the baffle 6 of the fuel cell stack of the present invention can be a simple "L" shape, "C" shape, triangular shape, or stepped shape, etc. Its shape and size are not uniquely determined, and can be designed by comprehensively considering factors such as the gas flow requirements, manufacturability, and production costs of different fuel cell stack flow fields.

[0035] like Figure 1 and Figure 2 As shown, the two end plates are the first end plate 3 and the second end plate 5, respectively. The second air inlet 31 and the second air outlet 32 ​​are both located on the first end plate 3, and both the second air inlet 31 and the second air outlet 32 ​​are rectangular holes.

[0036] like Figure 4 and Figure 5 As shown, the baffle 6 includes a first plate 61 and a second plate 62 connected in sequence. The first plate 61 is perpendicular to the end plate and connected to the first end plate 3. The second plate 62 is parallel to the end plate. The second plate 62 is located on the side of the first plate 61 away from the first end plate 3 and on the side of the first plate 61 close to the battery flow channel 2.

[0037] like Figure 5As shown, the baffle 6 also includes a third plate 63, which is parallel to the second plate 62. The third plate 63 is connected to the first plate 61 and is located between the second plate 62 and the first end plate 3.

[0038] Specifically, the battery flow channel 2 extends along a second direction perpendicular to the gas flow direction in the inlet flow channel 11, the inlet flow channel 11 and the outlet flow channel 12 are located at the two ends of the battery flow channel 2 respectively, and the width of the third plate 63 in the second direction is smaller than the width of the second plate 62 in the second direction.

[0039] like Figure 6 As shown, the baffle 6 includes an arc-shaped plate 64, which is connected to the first end plate 3. Along the direction away from the first end plate 3, the distance between the arc-shaped plate 64 and the battery flow channel 2 gradually decreases.

[0040] like Figure 7 As shown, the battery flow channel 2 extends along a second direction parallel to the first end plate 3, and the baffle 6 includes a triangular plate 65 connected to the first end plate 3. Along the direction away from the first end plate 3, the width of the triangular plate 65 gradually increases in the second direction.

[0041] Specifically, the triangular plate 65 is a right-angled triangular plate. The first outer side of the right-angled triangular plate, including one right-angled side, is located on the side of the air intake channel 11 away from the battery flow channel 2. The second outer side of the right-angled triangular plate, including the other right-angled side, is spaced apart from the first end plate 3.

[0042] Preferably, the end plate and the baffle 6 are integrally formed or detachably connected; and / or the end plate and the baffle 6 are made of the same material.

[0043] like Figures 1 to 3 As shown, the size and shape of the second air inlet 31 are exactly the same as the size and shape of the first air inlet 41 on each single battery 4, and both the second air inlet 31 and the first air inlet 41 are rectangular holes. The size and shape of the second air outlet 32 ​​are exactly the same as the size and shape of the first air outlet 42 on each single battery 4, and both the second air outlet 32 ​​and the first air outlet 42 are rectangular holes.

[0044] In addition, considering the universality of the static pressure recovery principle, the optimization design of the fuel cell stack flow field and end plate can be extended beyond the air inlet. The blind end and air outlet of the fuel cell stack can also achieve the same effect of controlling flow distribution through similar optimization design.

[0045] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0046] The fuel cell stack of the present invention includes: a battery assembly, comprising a plurality of single cells 4 spaced apart along a first direction, each single cell 4 having a battery flow channel 2 on one side, and each single cell 4 having a first air inlet 41 and a first air outlet 42 spaced apart and communicating with the battery flow channel 2, for forming an air inlet channel 11 and an air outlet channel 12 of the fuel cell stack respectively; two end plates spaced apart on opposite sides of the battery assembly along the first direction, one end plate having a second air inlet 31 and a second air outlet 32 ​​spaced apart and communicating with the air inlet channel 11 and the air outlet channel 12 respectively; a baffle 6, one end of the baffle 6 being connected to the wall of the second air inlet 31, the other end of the baffle 6 being inserted into the inlet of the air inlet channel 11, and the baffle 6 being located on the side of the air inlet channel 11 away from the battery flow channel 2. Thus, by setting a baffle 6 at the second air inlet 31 of the end plate of the fuel cell stack, when the external airflow enters the air inlet channel 11, its flow will be hindered by the baffle 6, and part of the dynamic pressure will be converted into static pressure, which will increase the static pressure at the location of the baffle 6. At the same time, due to the change in the gas flow direction at this location, part of the dynamic pressure gas will enter the corresponding battery flow channel 2. Therefore, the flow rate of the gas entering the battery flow channel 2 from the location of the baffle 6 will also increase, which will lead to an increase in the current density and heat generation of the fuel cell stack, and ultimately improve the cold start performance of the fuel cell stack, solving the problem of the small gas flow rate in the battery flow channel near the inlet end of the fuel cell stack in the prior art.

[0047] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0049] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0050] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0051] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fuel cell stack, characterized in that, include: The battery assembly includes a plurality of single cells (4) spaced apart along a first direction. Each single cell (4) has a battery flow channel (2) on one side, and each single cell (4) has a first air inlet (41) and a first air outlet (42) spaced apart and communicating with the battery flow channel (2) to form the air inlet channel (11) and air outlet channel (12) of the fuel cell stack, respectively. Two end plates are spaced apart on opposite sides of the battery assembly along a first direction, and one of the end plates is spaced apart with a second air inlet (31) and a second air outlet (32) for communicating with the air inlet channel (11) and the air outlet channel (12), respectively. Baffle (6), one end of which is connected to the wall of the second air inlet (31), and the other end of which is used to be inserted at the entrance of the air intake channel (11), and the baffle (6) is located on the side of the air intake channel (11) away from the battery channel (2). The two end plates are the first end plate (3) and the second end plate (5), respectively. The second air inlet (31) and the second air outlet (32) are both located on the first end plate (3), and the second air inlet (31) and the second air outlet (32) are both rectangular holes. The baffle (6) includes a first plate (61) and a second plate (62) connected in sequence. The first plate (61) is perpendicular to the end plate and connected to the first end plate (3). The second plate (62) is parallel to the end plate. The second plate (62) is located on the side of the first plate (61) away from the first end plate (3) and on the side of the first plate (61) close to the battery flow channel (2). The baffle (6) further includes a third plate (63), which is parallel to the second plate (62). The third plate (63) is connected to the first plate (61) and located between the second plate (62) and the first end plate (3).

2. The fuel cell stack according to claim 1, characterized in that, The battery flow channel (2) extends along a second direction perpendicular to the gas flow direction in the inlet flow channel (11). The inlet flow channel (11) and the outlet flow channel (12) are located at the two ends of the battery flow channel (2), respectively. The width of the third plate (63) in the second direction is smaller than the width of the second plate (62) in the second direction.

3. The fuel cell stack according to claim 1 or 2, characterized in that, The end plate and the baffle (6) are integrally formed or detachably connected; and / or The end plate and the baffle (6) are made of the same material.

4. The fuel cell stack according to claim 1 or 2, characterized in that, The size and shape of the second air inlet (31) are exactly the same as the size and shape of the first air inlet (41) on each of the single batteries (4), and the size and shape of the second air outlet (32) are exactly the same as the size and shape of the first air outlet (42) on each of the single batteries (4).

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