Bipolar plates and fuel cells

Abstract

The present application provides a bipolar plate and a fuel cell. The bipolar plate comprises a cathode plate (1) and an anode plate (2), wherein the cathode plate (1) comprises an air inlet (3), an air outlet (4) and an air flow channel (5), wherein a first end of the air flow channel (5) is connected to the air inlet (3), a second end of the air flow channel (5) is connected to the air outlet (4), and the air outlet (4) fully covers the air flow channel (5). According to the bipolar plate of the present application, it is possible to ensure the timely discharge of liquid water on the cathode side, thereby greatly improving the working stability of the bipolar plate under high current density.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cells, and in particular to a bipolar plate and a fuel cell. Background Art

[0002] As an important component of fuel cells, bipolar plates have the functions of current collection, membrane electrode support and uniform distribution of reaction gases. Metal bipolar plates are generally made of two metal plates by welding (graphite bipolar plates have two graphite plates bonded together, and the following mainly uses metal bipolar plates as an example for explanation). The space formed by the two metal plates is generally used as a flow space for the coolant to circulate the cooling liquid, and multiple flow channels are arranged on the surface of the metal plates for the circulation of reaction gases. Considering that the cathode side of the fuel cell is the main place where water is produced during the reaction, the drainage performance of the cathode flow field must also be considered under high current density. Therefore, for metal plates, it is necessary to use clever structural design to ensure that the three working fluids - air, hydrogen and cooling water can be safely isolated, and to ensure good drainage performance as much as possible. This is the main difficulty in the design of metal bipolar plates.

[0003] For the bipolar plates of the prior art, since the hydrogen inlet / outlet, the air inlet / outlet and the cooling water inlet / outlet are arranged side by side, the width of the air inlet / outlet is narrow due to the crowding out of the hydrogen inlet / outlet and the cooling water inlet / outlet, which is much smaller than the width of the air flow channel in the middle area. In order to ensure uniform air distribution, it is necessary to add a diversion structure on the air inlet side. At the same time, on the air outlet side, due to the narrowing of the width from the middle area to the air outlet position, there will be a contraction of the air flow channel, and this contraction is generally manifested as a reduction in the number of flow channels. This will cause the air flow channel to become narrower, and the water generated during the reaction will have a large flow resistance on the outlet side of the air flow channel. Under higher current density, the drainage capacity of the air flow channel is insufficient, and liquid water cannot be discharged from the flow channel in time, which greatly reduces the working stability of the plate under high current density. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present application is to provide a bipolar plate and a fuel cell that can ensure the timely discharge of liquid water on the cathode side and greatly improve the working stability of the bipolar plate under high current density.

[0005] In order to solve the above problems, the present application provides a bipolar plate, including a cathode plate and an anode plate, the cathode plate includes an air inlet, an air outlet and an air flow channel, the first end of the air flow channel is connected to the air inlet, the second end of the air flow channel is connected to the air outlet, and the air outlet fully covers the air flow channel.

[0006] Preferably, the total width of the air flow channel is constant along the direction from the air inlet to the air outlet.

[0007] Preferably, the air inlet is located at the first end of the long side of the cathode plate, and the air outlet is located at the second end of the long side of the cathode plate, and the air inlet is located at the first end of the short side of the cathode plate, and the air outlet is located at the second end of the short side of the cathode plate.

[0008] Preferably, the air flow channel includes an arc segment and a straight segment, the arc segment is arranged at both ends of the straight segment, the first end of the straight segment is connected to the air inlet through the arc segment, and the second end of the straight segment is connected to the air outlet through the arc segment.

[0009] Preferably, there are multiple air flow channels, and the length and width of each air flow channel are the same.

[0010] Preferably, the cathode plate further comprises a hydrogen inlet and a hydrogen outlet, the hydrogen inlet is located at the second end of the long side of the cathode plate, and the hydrogen outlets are respectively located at the first end of the long side of the cathode plate, the hydrogen inlet is located at the first end of the short side of the cathode plate, and the hydrogen outlets are located at the second end of the short side of the cathode plate.

[0011] Preferably, the cathode plate further comprises a cooling liquid inlet and a cooling liquid outlet, the cooling liquid inlet is located at the first end of the long side of the cathode plate, the cooling liquid outlet is located at the second end of the long side of the cathode plate, a cooling liquid flow channel is provided on the back side of the cathode plate, the first end of the cooling liquid flow channel is connected to the cooling liquid inlet, and the second end of the cooling liquid flow channel is connected to the cooling liquid outlet.

[0012] Preferably, the coolant inlet and / or the coolant outlet completely covers the coolant flow channel.

[0013] Preferably, adjacent air flow channels are separated by spacing protrusions, and the coolant flow channel is located on the back side of the spacing protrusions.

[0014] Preferably, the anode plate and the cathode plate have the same structure.

[0015] Preferably, the anode plate and the cathode plate are mirror-symmetrical, and the anode plate and the cathode plate are stacked to form a bipolar plate.

[0016] Preferably, the back sides of the anode plate and the cathode plate are bonded together to form a cooling liquid channel. When the cathode plate includes a cooling liquid inlet and a cooling liquid outlet, one end of the cooling liquid channel is connected to the cooling liquid inlet, and the other end of the cooling liquid channel is connected to the cooling liquid outlet.

[0017] Preferably, flow field areas are formed at both ends of the coolant channel, and the coolant flow channel on the anode plate intersects with the coolant flow channel on the cathode plate in the flow field area to form overlapping areas and non-overlapping areas, and the coolant inlet is connected to the coolant channel through the flow field area of ​​the non-overlapping area.

[0018] Preferably, the flow field area located outside the coolant flow channel of the anode plate completely covers the coolant flow channel of the cathode plate and is connected to the coolant flow channel of the cathode plate, and the flow field area located outside the coolant flow channel of the cathode plate completely covers the coolant flow channel of the anode plate and is connected to the coolant flow channel of the anode plate.

[0019] Preferably, the flow field region located in the non-overlapping region is provided with a supporting protrusion, and the supporting protrusion is located between the anode plate and the cathode plate, and is used to support the cathode plate and the anode plate.

[0020] Preferably, the bipolar plate is a metal plate, a graphite plate or a composite graphite plate; and / or, the bipolar plate is formed by stamping or carving.

[0021] Preferably, the thickness of the cathode plate is 0.01-1 mm; and / or the air flow channel of the cathode plate has a depth of 0.1-10 mm and a flow channel width of 0.1-10 mm.

[0022] According to another aspect of the present application, a fuel cell is provided, comprising a bipolar plate, which is the bipolar plate described above.

[0023] The bipolar plate provided in the present application comprises a cathode plate and an anode plate, wherein the cathode plate comprises an air inlet, an air outlet and an air flow channel, wherein the first end of the air flow channel is connected to the air inlet, the second end of the air flow channel is connected to the air outlet, and the air outlet fully covers the air flow channel. In the present application, the air outlet is modified so that the air outlet can fully cover all the air flow channels, so that all the air flow channels can be directly connected to the air outlet, so that no shunt structure is required, and it is not easy to have a sudden change in the width of the fluid channel, so that the width of the air flow channel from the middle area to the air outlet position is basically the same, and the contraction of the air flow channel is avoided, so that the water generated during the reaction can be smoothly discharged at the outlet side of the air flow channel, and the flow resistance of the liquid water at the outlet side of the air flow channel is reduced. Under a relatively large current density, the drainage capacity of the air flow channel can be guaranteed, so that the liquid water can be discharged from the air flow channel in time, which greatly improves the working stability of the bipolar plate under a large current density. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an exploded structural diagram of a bipolar plate according to an embodiment of the present application;

[0025] Figure 2 A partial enlarged view of the cathode plate of the bipolar plate of the embodiment of the present application;

[0026] Figure 3 A schematic diagram of the structure of the cooling liquid flow channel of the bipolar plate of an embodiment of the present application;

[0027] Figure 4 This is a schematic diagram of the enlarged structure of the bipolar plate in the flow field area of ​​an embodiment of the present application.

[0028] The reference numerals are as follows:

[0029] 1. Cathode plate; 2. Anode plate; 3. Air inlet; 4. Air outlet; 5. Air flow channel; 6. Arc segment; 7. Straight segment; 8. Hydrogen inlet; 9. Air outlet; 10. Coolant inlet; 11. Coolant outlet; 12. Spacing protrusions; 13. Coolant flow channel; 14. Overlapping area; 15. Non-overlapping area. DETAILED DESCRIPTION

[0030] See also Figures 1 to 4 As shown, according to an embodiment of the present application, the bipolar plate includes a cathode plate 1 and an anode plate 2, the cathode plate 1 includes an air inlet 3, an air outlet 4 and an air flow channel 5, the first end of the air flow channel 5 is connected to the air inlet 3, the second end of the air flow channel 5 is connected to the air outlet 4, and the air outlet 4 fully covers the air flow channel 5.

[0031] In the present application, the air outlet 4 is modified so that the air outlet 4 can fully cover all the air flow channels 5, so that all the air flow channels 5 can be directly connected to the air outlet 4, so there is no need for a diversion structure, and it is not easy to have a sudden change in the width of the fluid channel, so that the width of the air flow channel 5 from the middle area to the position of the air outlet 4 is basically the same, and the number is basically the same, which avoids the change in the number of air flow channels 5 and the contraction of the air flow channels 5, so that the water generated during the reaction can be discharged smoothly on the outlet side of the air flow channel 5 without clogging, reducing the flow resistance of liquid water on the outlet side of the air flow channel 5, and under a larger current density, the drainage capacity of the air flow channel 5 can be guaranteed, so that liquid water can be discharged from the air flow channel 5 in time, greatly improving the working stability of the bipolar plate under high current density.

[0032] In an optional embodiment, the total width of the air flow channel 5 is constant along the direction from the air inlet 3 to the air outlet 4. Specifically, the air inlet 3 also fully covers the air flow channel 5, that is, the total length of the air inlet 3 is greater than or equal to the total width of the air flow channel 5, so that the air flow channel 5 can be directly extended to the air inlet 3 and communicated with the air inlet 3.

[0033] In this embodiment, since the total width of the air flow channel 5 is constant, the air flow in the air flow channel will not change suddenly. Moreover, since the overall width of the air flow channel 5 is large, it will not hinder the flow of liquid water, which can reduce the flow resistance and make the cathode plate 1 have a stronger drainage ability, thereby improving the battery performance to a certain extent and extending the battery life.

[0034] The fuel cell improves the flow-conducting performance of the air flow channel 5 by changing the corresponding relationship between the air outlet 4 and the air flow channel 5, and has a relatively simple structure, thereby increasing the formability of the bipolar plate.

[0035] The air inlet 3 is located at the first end of the long side of the cathode plate 1, and the air outlet 4 is located at the second end of the long side of the cathode plate 1, respectively. The air inlet 3 is located at the first end of the short side of the cathode plate 1, and the air outlet 4 is located at the second end of the short side of the cathode plate 1. Since the air inlet 3 and the air outlet 4 are respectively arranged at the two ends of the short side of the cathode plate 1 and extend along the length direction of the cathode plate 1, the length setting of the air inlet 3 and the air outlet 4 is not limited by the width of the cathode plate 1, and can have a larger length, which can meet the requirement of fully covering the air flow channel 5, and does not need to limit the width of the air flow channel 5 at the end position, and can achieve uniformity of flow distribution without complex guide or diversion structures, so that the fluid in the air flow channel 5 can flow evenly and smoothly, improve the uniformity and flow efficiency of the fluid flow, improve the drainage efficiency, and ensure sufficient air supply.

[0036] The air flow channel 5 includes an arc segment 6 and a straight segment 7. The arc segment 6 is arranged at both ends of the straight segment 7. The first end of the straight segment 7 is connected to the air inlet 3 through the arc segment 6, and the second end of the straight segment 7 is connected to the air outlet 4 through the arc segment 6. In the present application, the arc flow channel and the straight flow channel are used in combination, so that the arc flow channel and the straight flow channel are in contact and tangent, so that the fluid can be guided and the fluid flow loss can be reduced. In addition, the arc flow channel structure can also more conveniently achieve the connection between the air flow channel 5 and the air inlet 3 and the air outlet 4, and the width of each air flow channel 5 does not need to be changed, so that the width of the air flow channel 5 is kept constant throughout the entire process from the air inlet 3 to the air outlet 4, which can more effectively ensure the uniform distribution of the fluid, and there will be no problem of change in the flow channel width, thereby improving the flow stability and drainage stability of the flow channel fluid.

[0037] In addition, in this embodiment, the air flow channel 5 only forms arc-shaped flow channels at the flow paths at both ends to realize the conversion of the fluid flow direction, and most of the flow paths in the middle are mainly straight flow channels, so the flow resistance of the fluid can be further reduced. After the air enters the air flow channel 5, it will first enter the straight flow channel through the arc-shaped flow channel from the air inlet 3 on one side of the cathode plate 1, and then flow out of the straight flow channel and pass through the arc-shaped flow channel again to convert the flow direction, and finally be discharged from the air outlet 4 on the other side of the cathode plate to realize the smooth flow of the fluid.

[0038] In some embodiments, there are multiple air flow channels 5, and the length and width of each air flow channel 5 are the same, ensuring that each air flow channel 5 has the same flow resistance, so that the fluid flow speed in each air flow channel 5 is basically the same, the fluidity is better, and the discharge of unreacted cathode gas and liquid water generated by the reaction is more convenient, which greatly improves the working stability of the plate under high current density.

[0039] The cathode plate 1 also includes a hydrogen inlet 8 and a hydrogen outlet 9. The hydrogen inlet 8 is located at the second end of the long side of the cathode plate 1, and the hydrogen outlet 9 is located at the first end of the long side of the cathode plate 1. The hydrogen inlet 8 is located at the first end of the short side of the cathode plate 1, and the hydrogen outlet 9 is located at the second end of the short side of the cathode plate 1.

[0040] The hydrogen inlet 8 and the hydrogen outlet 9 in this embodiment also extend along the length direction of the cathode plate 1, so that the hydrogen inlet 8 and the hydrogen outlet 9 can also have a sufficient length to achieve full coverage and connectivity of the hydrogen flow channel, thereby improving the uniformity of hydrogen flow into the hydrogen flow channel.

[0041] The cathode plate 1 also includes a cooling liquid inlet 10 and a cooling liquid outlet 11. The cooling liquid inlet 10 is located at the first end of the long side of the cathode plate 1, and the cooling liquid outlet 11 is located at the second end of the long side of the cathode plate 1. A cooling liquid channel 13 is provided on the back side of the cathode plate 1. The first end of the cooling liquid channel 13 is connected to the cooling liquid inlet 10, and the second end of the cooling liquid channel 13 is connected to the cooling liquid outlet 11.

[0042] In this embodiment, the air inlet 3 and the air outlet 4 are arranged at the two ends of the short side of the cathode plate 1, and the hydrogen inlet 8 and the hydrogen outlet 9 are also arranged at the two ends of the short side of the cathode plate 1, and the air inlet 3 and the air outlet 4 are arranged diagonally, and the hydrogen inlet 8 and the hydrogen outlet 9 are also arranged diagonally, the air inlet 3 and the hydrogen inlet 8 or the hydrogen inlet 8 are staggered, and the air outlet 4 and the hydrogen inlet 8 or the hydrogen inlet 8 are staggered, so that there is no interference between the air inlet / outlet and the hydrogen inlet / outlet, which improves the rationality of the layout of the air inlet / outlet and the hydrogen inlet / outlet.

[0043] The positions of the air inlet / outlet and the hydrogen inlet / outlet on the anode plate 2 correspond to those of the air inlet / outlet and the hydrogen inlet / outlet on the cathode plate 1 .

[0044] The coolant inlet 10 and / or the coolant outlet 11 completely covers the coolant flow channel 13 .

[0045] Since the air inlet 3, the air outlet 4, the hydrogen inlet 8 and the hydrogen outlet 9 are all arranged at the two ends of the short side of the cathode plate 1, and are not arranged at the end positions of the two ends of the long side of the cathode plate 1, the lengths of the coolant inlet 10 and the coolant outlet 11 will not be restricted by the air inlet 3, the air outlet 4, the hydrogen inlet 8 and the hydrogen outlet 9, and the lengths of the coolant inlet 10 and the coolant outlet 11 can be limited according to the width of the coolant flow channel 13, so that the lengths of the coolant inlet 10 and the coolant outlet 11 can fully cover the coolant flow channel 13, so that the coolant can enter the coolant flow channel 13 at the maximum flow rate from the coolant inlet 10, and then flow through the entire coolant flow channel 13 at the maximum flow rate, and then flow out from the coolant outlet 11 at the maximum flow rate, which can improve the flow efficiency of the coolant in the coolant flow channel 13 and improve the heat dissipation effect of the bipolar plate.

[0046] The air inlet and the hydrogen inlet will not interfere with or compete with the cooling water inlet in space, thereby ensuring the uniformity of the flow distribution of the anode and cathode and the cooling water flow channel inlet.

[0047] Adjacent air flow channels 5 are separated by spacing protrusions 12, and the coolant flow channel 13 is located on the back side of the spacing protrusions 12. The structure of the cathode plate 1 can be more fully utilized to design the coolant flow channel 13, and the structure of the coolant flow channel 13 is made similar to that of the air flow channel 5. A structure of two arc flow channels and a straight flow channel in the middle is adopted to reduce the flow resistance of the coolant, improve the flow efficiency of the coolant, and improve the cooling capacity of the coolant.

[0048] In an optional embodiment, the anode plate 2 has the same structure as the cathode plate 1. In this way, since the structures of the cathode plate 1 and the anode plate 2 are exactly the same, only one set of molds can be used to complete the mold opening of the cathode plate 1 and the anode plate 2, thereby greatly reducing the mold opening cost and effectively improving the structural consistency of the cathode plate 1 and the anode plate 2.

[0049] In one embodiment, the anode plate 2 and the cathode plate 1 are mirror-symmetrical, and the anode plate 2 and the cathode plate 1 are stacked to form a bipolar plate. In this embodiment, the anode plate 2 and the cathode plate 1 are mirror-symmetrical, that is, one of the cathode plates 1 is placed normally, and then the other cathode plate 1 is flipped 180° around the long side of the cathode plate 1, and the flipped cathode plate 1 is used as the anode plate 2, which is stacked on the cathode plate 1 and welded together to form a bipolar plate.

[0050] The back sides of the anode plate 2 and the cathode plate 1 are bonded together to form a cooling liquid channel. When the cathode plate 1 includes a cooling liquid inlet 10 and a cooling liquid outlet 11, one end of the cooling liquid channel is connected to the cooling liquid inlet 10, and the other end of the cooling liquid channel is connected to the cooling liquid outlet 11.

[0051] Flow field areas are formed at both ends of the coolant channel. The coolant channel 13 on the anode plate 2 intersects with the coolant channel 13 on the cathode plate 1 in the flow field area to form an overlapping area 14 and a non-overlapping area 15. The coolant inlet 10 is connected to the coolant channel through the flow field area of ​​the non-overlapping area 15.

[0052] Specifically, in this embodiment, since the two ends of the coolant flow channel 13 on the anode plate 2 adopt arc-shaped flow channels and the middle adopts a straight flow channel, and the two ends of the coolant flow channel 13 on the cathode plate 1 adopt arc-shaped flow channels and the middle adopts a straight flow channel, and the arc-shaped flow channel of the coolant flow channel 13 on the anode plate 2 and the arc-shaped flow channel of the coolant flow channel 13 on the cathode plate 1 are bent in opposite directions, the arc-shaped flow channel of the coolant flow channel 13 on the anode plate 2 and the arc-shaped flow channel of the coolant flow channel 13 on the cathode plate 1 intersect with each other to form an overlapping area 14 and a non-overlapping area 15, and the flow field area outside the overlapping area 14 and the non-overlapping area 15 is a blank area. The non-overlapping area 15 refers to an area where there is a flow channel on one plate and no flow channel on the other plate.

[0053] Since the arcuate flow channel of the anode plate 2 corresponds to the plane area of ​​the cathode plate 1 in the non-overlapping area 15, and this part of the plane area is recessed in the direction away from the anode plate 2, a fluid channel can be formed between the plane area of ​​the cathode plate 1 and the arcuate flow channel in the non-overlapping area 15 of the anode plate 2, and the coolant can enter the overlapping area 14 through the plane area and the arcuate flow channel of the anode plate 2. Similarly, the arcuate flow channel of the cathode plate 1 can also form a fluid channel between the plane area of ​​the anode plate 2 in the non-overlapping area 15, and the coolant can enter the overlapping area 14 through the plane area and the arcuate flow channel of the cathode plate 1. The two streams of coolant converge in the overlapping area 14, and then enter the middle area of ​​the anode and cathode plates in the staggered grid flow field, flow in the middle of the bipolar plate, and finally flow out from the coolant outlet 11.

[0054] The flow field area located outside the coolant flow channel 13 of the anode plate 2 completely covers the coolant flow channel 13 of the cathode plate 1 and is connected to the coolant flow channel 13 of the cathode plate 1. The flow field area located outside the coolant flow channel 13 of the cathode plate 1 completely covers the coolant flow channel 13 of the anode plate 2 and is connected to the coolant flow channel 13 of the anode plate 2, so that the coolant can fully enter each coolant flow channel 13 through the flow field area, making the coolant distribution more uniform.

[0055] In other embodiments, the hydrogen inlet and / or the air inlet and / or the air inlet may partially occupy the non-overlapping area as long as the connection between the coolant channel 13 and the coolant inlet and / or the air inlet is not affected. This structure can change the hydrogen inlet and / or the air inlet and / or the air inlet into a triangle or a trapezoid, thereby increasing the area of ​​the hydrogen inlet and / or the air inlet and / or the air inlet and / or the air inlet.

[0056] For the bipolar plate, the gas flow paths participating in the reaction flow from the upper surface and the lower surface of the bipolar plate respectively. In the actual design, the air flow path of the cathode plate 1 can be set opposite to the hydrogen flow path of the anode plate 2, or the air flow path of the cathode plate 1 can be set the same as the hydrogen flow path of the anode plate 2.

[0057] The flow field region located in the non-overlapping region 15 is provided with a supporting protrusion, and the supporting protrusion is located between the anode plate 2 and the cathode plate 1 , and is used to support the cathode plate 1 and the anode plate 2 .

[0058] Two monopolar plates are stacked to form a bipolar plate, and a flow space for cooling liquid is formed between the two monopolar plates. The overlapping area 14 where the flow field areas of the two plates overlap can support each other, while in the non-overlapping area 15, it is necessary to set a supporting protrusion on the plate without a flow channel structure, so as to support the plate and the plate with the flow channel to form a cooling water flow space. The blank area outside the overlapping area 14 and the non-overlapping area 15 can be cut off so that the coolant inlet 10 or the coolant outlet 11 can extend to a position close to the non-overlapping area 15, forming a triangular or trapezoidal coolant inlet and outlet, thereby expanding the coolant inlet and outlet area, and can also be formed by correspondingly setting supporting protrusions on the upper and lower plates to support each other and form a coolant flow space. The above-mentioned coolant is, for example, cooling water.

[0059] The bipolar plate is a metal plate, a graphite plate or a composite graphite plate; and / or the monopolar plate of the bipolar plate is formed by stamping or carving.

[0060] The monopolar plate is stamped or carved from a stainless steel metal sheet with a thickness of 0.01-1mm, and can also be stamped or carved from a graphite plate or a composite graphite plate. The length of the monopolar plate is 1-1000mm, the width is 1-1000mm, the flow channel depth is 0.1-10mm, and the groove width at the edge of the monopolar plate and the fluid flow channel width on the monopolar plate can both be 0.1-10mm.

[0061] According to an embodiment of the present application, a fuel cell includes a bipolar plate, which is the bipolar plate described above.

[0062] The bipolar plate of the present application focuses on improving the intake flow uniformity of cathode air and anode hydrogen without the use of complex flow guidance and diversion structures. At the same time, the flow channel structure designed in the present application has good fluidity and low flow resistance, which is particularly suitable for the discharge of unreacted cathode gas and liquid water generated by the reaction, greatly improving the working stability of the plate under high current density.

[0063] The designed flow channel is formed by a combination of straight flow channels and arc flow channels. The characteristic of the combined flow channel is that each combined flow channel has the same length, which ensures that each combined flow channel has the same flow resistance and the flow resistance is not too large. Multiple parallel combined flow channels form the main channel for the circulation of reaction gas, and the area between the two monopolar plates forms a flow channel for direct coolant.

[0064] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0065] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A bipolar plate, characterized in that: It comprises a cathode plate (1) and an anode plate (2), wherein the cathode plate (1) comprises an air inlet (3), an air outlet (4) and an air flow channel (5), wherein a first end of the air flow channel (5) is connected to the air inlet (3), a second end of the air flow channel (5) is connected to the air outlet (4), and the air outlet (4) completely covers the air flow channel (5); The anode plate (2) has the same structure as the cathode plate (1); The back sides of the anode plate (2) and the cathode plate (1) are bonded together to form a cooling liquid channel, and when the cathode plate (1) comprises a cooling liquid inlet (10) and a cooling liquid outlet (11), one end of the cooling liquid channel is connected to the cooling liquid inlet (10), and the other end of the cooling liquid channel is connected to the cooling liquid outlet (11); The two ends of the cooling liquid channel form a flow field area, the cooling liquid channel (13) on the anode plate (2) and the cooling liquid channel (13) on the cathode plate (1) intersect in the flow field area to form an overlapping area (14) and a non-overlapping area (15), and the cooling liquid inlet (10) is connected to the cooling liquid channel through the flow field area of ​​the non-overlapping area (15).

2. The bipolar plate according to claim 1, characterized in that: Along the direction from the air inlet (3) to the air outlet (4), the total width of the air flow channel (5) is constant.

3. The bipolar plate according to claim 1, characterized in that: The air inlet (3) is located at the first end of the long side of the cathode plate (1), and the air outlet (4) is located at the second end of the long side of the cathode plate (1). The air inlet (3) is located at the first end of the short side of the cathode plate (1), and the air outlet (4) is located at the second end of the short side of the cathode plate (1).

4. The bipolar plate according to claim 3, characterized in that: The air flow channel (5) comprises an arc segment (6) and a straight segment (7); the arc segment (6) is arranged at both ends of the straight segment (7); the first end of the straight segment (7) is connected to the air inlet (3) through the arc segment (6); and the second end of the straight segment (7) is connected to the air outlet (4) through the arc segment (6).

5. The bipolar plate according to claim 4, characterized in that: There are a plurality of air flow channels (5), and each of the air flow channels (5) has the same length and width.

6. The bipolar plate according to claim 1, characterized in that: The cathode plate (1) further comprises a hydrogen inlet (8) and a hydrogen outlet (9), wherein the hydrogen inlet (8) is located at the second end of the long side of the cathode plate (1), and the hydrogen outlet (9) is located at the first end of the long side of the cathode plate (1), respectively; the hydrogen inlet (8) is located at the first end of the short side of the cathode plate (1), and the hydrogen outlet (9) is located at the second end of the short side of the cathode plate (1).

7. The bipolar plate according to claim 1, characterized in that: The cathode plate (1) further comprises a cooling liquid inlet (10) and a cooling liquid outlet (11), wherein the cooling liquid inlet (10) is located at a first end of a long side of the cathode plate (1), and the cooling liquid outlet (11) is located at a second end of the long side of the cathode plate (1), and a cooling liquid flow channel (13) is provided on the back side of the cathode plate (1), wherein a first end of the cooling liquid flow channel (13) is connected to the cooling liquid inlet (10), and a second end of the cooling liquid flow channel (13) is connected to the cooling liquid outlet (11).

8. The bipolar plate according to claim 7, characterized in that: The cooling liquid inlet (10) and / or the cooling liquid outlet (11) completely covers the cooling liquid flow channel (13).

9. The bipolar plate according to claim 7, characterized in that: Adjacent air flow channels (5) are separated by spacing protrusions (12), and the coolant flow channel (13) is located on the back side of the spacing protrusions (12).

10. The bipolar plate according to claim 1, characterized in that: The anode plate (2) and the cathode plate (1) are mirror-symmetrical, and the anode plate (2) and the cathode plate (1) are stacked to form the bipolar plate.

11. The bipolar plate according to claim 1, characterized in that: The flow field area located outside the cooling liquid flow channel (13) of the anode plate (2) completely covers the cooling liquid flow channel (13) of the cathode plate (1) and is in communication with the cooling liquid flow channel (13) of the cathode plate (1); the flow field area located outside the cooling liquid flow channel (13) of the cathode plate (1) completely covers the cooling liquid flow channel (13) of the anode plate (2) and is in communication with the cooling liquid flow channel (13) of the anode plate (2).

12. The bipolar plate according to claim 1, characterized in that: A support protrusion is provided in the flow field area located in the non-overlapping area (15); the support protrusion is located between the anode plate (2) and the cathode plate (1) and is used to support the cathode plate (1) and the anode plate (2).

13. The bipolar plate according to any one of claims 1 to 9, 11 to 12, characterized in that: The bipolar plate is a metal plate, a graphite plate or a composite graphite plate; and / or, the bipolar plate is formed by stamping or carving.

14. The bipolar plate according to any one of claims 1 to 9, 11 to 12, characterized in that: The thickness of the cathode plate (1) is 0.01-1 mm; and / or the air flow channel (5) of the cathode plate (1) has a depth of 0.1-10 mm and a flow channel width of 0.1-10 mm.

15. A fuel cell comprising a bipolar plate, characterized in that: The bipolar plate is the bipolar plate according to any one of claims 1 to 14.

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