A fuel cell bipolar plate

Abstract

This application relates to a bipolar plate for a fuel cell, wherein a first flow field includes a first through-hole, a first bridge channel, a first distribution zone, a first gas reaction zone, a first sub-collection zone, a second bridge channel, and a second through-hole through which gas flows from left to right, and the flow channel length of the first distribution zone is the same as the flow channel length of the first sub-collection zone; a second flow field includes a sixth through-hole, a sixth bridge channel, a third distribution zone, a third gas reaction zone, a third sub-collection zone, a fifth bridge channel, and a fifth through-hole through which gas flows from right to left, and the flow channel length of the third sub-collection zone is the same as the flow channel length of the third distribution zone; a third flow field includes a third through-hole, a third bridge channel, a second sub-collection zone, a second gas reaction zone, a second distribution zone, a fourth bridge channel, and a fourth through-hole through which liquid flows from left to right, and the flow channel length of the second distribution zone is the same as the flow channel length of the second sub-collection zone; thus achieving equal lengths for each flow channel from inlet to outlet.

Description

Technical Field

[0001] This utility model relates to the field of fuel cell technology, specifically to a fuel cell bipolar plate. Background Technology

[0002] With the rapid increase in energy demand from modern industry, the harmful substances released during the combustion of traditional fossil fuels are continuously worsening the ecological environment. The need for new clean energy sources is becoming increasingly urgent. A fuel cell is a chemical device that can directly convert the chemical energy of fuel into electrical energy. It is not limited by the Carnot cycle effect and has high conversion efficiency. It produces no noise pollution and no harmful gas emissions, making it suitable for a wide range of applications.

[0003] Bipolar plates are one of the most important components of a fuel cell, accounting for approximately 70% of the stack's mass. Their functions include separating fuel and oxidant, collecting and conducting current, transferring and dissipating heat generated by the chemical reactions within the cell, and providing sufficient mechanical support for the flow channels. The flow field structure of the bipolar plates determines several important parameters, such as the effective reaction area ratio, the uniformity of reactant gas distribution, fuel cell power, current density, and voltage consistency. Typical bipolar plate flow fields include point flow fields, parallel direct-flow channels, interdigitated flow channels, and serpentine flow channels. Interdigitated channels have a large pressure drop and are prone to impacting and damaging the gas diffusion layer. Parallel channels suffer from uneven gas distribution and poor drainage. Serpentine channels, with their longer flow paths, may pose a risk of uneven gas concentration between the front and rear sections.

[0004] The different lengths of the flow channels lead to differences in the flow velocity and pressure of the fluid in each channel, resulting in uneven gas distribution and inconsistent reactions in different places. This, in turn, affects the current density, causes excessive temperature differences in different parts of the bipolar plate, and further affects the stability of the fuel cell output power. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a fuel cell bipolar plate that can make the reactions occurring in different parts of the bipolar plate more consistent, so as to avoid the uneven reaction caused by uneven gas distribution, which would affect the current density and cause excessive temperature differences in different parts of the bipolar plate.

[0006] The technical solution adopted by this utility model to solve its technical problem is:

[0007] A fuel cell bipolar plate includes a cathode plate and an anode plate, which are bonded together to form the bipolar plate. A first flow field is provided on the outer side of the cathode plate, a second flow field is provided on the outer side of the anode plate, and a third flow field is formed by the inner sides of the cathode plate and the anode plate being bonded together. The first flow field includes a first through hole, a first bridge channel, a first distribution zone, a first gas reaction zone, a first sub-collection zone, a second bridge channel, and a second through hole through which gas flows from left to right in sequence. The length of the flow channel in the first distribution zone is the same as the length of the flow channel in the first sub-collection zone.

[0008] The second flow field includes the sixth through hole, the sixth bridge channel, the third distribution zone, the third gas reaction zone, the third sub-collection zone, the fifth bridge channel, and the fifth through hole through which the gas flows from right to left in sequence. The flow channel length in the third sub-collection zone is the same as the flow channel length in the third distribution zone.

[0009] The third flow field includes the third through hole, the third bridge channel, the second sub-collection zone, the second gas reaction zone, the second distribution zone, the fourth bridge channel, and the fourth through hole through which the liquid flows from left to right in sequence. The flow channel length in the second distribution zone is the same as the flow channel length in the second sub-collection zone.

[0010] In one embodiment, the first distribution area includes a plurality of first distribution channels, which are fan-shaped and have a gradually increasing length from top to bottom. The first sub-collection area includes a plurality of first sub-collection channels, which are fan-shaped and have a gradually decreasing length from top to bottom.

[0011] The third sub-collection area includes several third sub-collection channels, which are fan-shaped and gradually increase in length from top to bottom. The third distribution area includes several third distribution channels, which are fan-shaped and gradually decrease in length from top to bottom.

[0012] In one embodiment, the third through hole is disposed between the first through hole and the fifth through hole; the fourth through hole is disposed between the sixth through hole and the second through hole.

[0013] In one embodiment, the first through hole and the second through hole are diagonally disposed on the bipolar plate; the fifth through hole and the sixth through hole are diagonally disposed on the bipolar plate.

[0014] In one embodiment, the dimensions of the first through hole and the second through hole are larger than the dimensions of the fifth through hole and the sixth through hole.

[0015] In one embodiment, the first gas reaction zone, the second gas reaction zone, and the third gas reaction zone each include a plurality of gas flow channels, and the cross-sectional area of ​​each gas flow channel varies periodically along the gas flow direction.

[0016] In one embodiment, each cross-sectional area change cycle of the gas flow channel includes a first wide diameter region, a first gradient region, a first narrow diameter region, a second gradient region, a second wide diameter region, a third gradient region, a second narrow diameter region, and a fourth gradient region connected in sequence. The cross-sectional area of ​​the first narrow diameter region is inclined downward along the gas flow direction and its diameter remains constant, while the cross-sectional area of ​​the second narrow diameter region is inclined upward along the gas flow direction and its diameter remains constant.

[0017] In one embodiment, the first gradient region, the first narrow diameter region, the second gradient region, and the third gradient region, the second narrow diameter region, and the fourth gradient region are mirror images of each other.

[0018] In one implementation, the first width region and the second width region are not on the same horizontal line.

[0019] In one embodiment, the cross-sectional area of ​​the first wide-diameter region is a direct-flow channel along the gas flow direction; the cross-sectional area of ​​the first gradient region is arc-shaped and its diameter gradually decreases along the gas flow direction; the cross-sectional area of ​​the second gradient region is arc-shaped and its diameter gradually increases along the gas flow direction; the cross-sectional area of ​​the second wide-diameter region is a direct-flow channel along the gas flow direction; the cross-sectional area of ​​the third gradient region is arc-shaped and its diameter gradually decreases along the gas flow direction; and the cross-sectional area of ​​the fourth gradient region is arc-shaped and its diameter gradually increases along the gas flow direction.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0021] This invention utilizes a first flow field comprising a first through-hole, a first bridge channel, a first distribution zone, a first gas reaction zone, a first sub-collection zone, a second bridge channel, and a second through-hole through which gas flows from left to right in sequence. The flow channel length in the first distribution zone is the same as the flow channel length in the first sub-collection zone. The second flow field comprises a sixth through-hole, a sixth bridge channel, a third distribution zone, a third gas reaction zone, a third sub-collection zone, a fifth bridge channel, and a fifth through-hole through which gas flows from right to left in sequence. The flow channel length in the third sub-collection zone is the same as the flow channel length in the third distribution zone. The flow channels are of uniform length; the third flow field includes the third through hole, the third bridge channel, the second sub-collection zone, the second gas reaction zone, the second distribution zone, the fourth bridge channel, and the fourth through hole through which the liquid flows from left to right in sequence. The flow channel length in the second distribution zone is the same as that in the second sub-collection zone, so that the length of each flow channel from the inlet to the outlet is equal, making the gas reaction time in each flow channel in the reaction zone tend to be uniform, so as to achieve uniform power generation effect in all parts of the reaction zone, and ultimately make the fuel cell power output stable, improving its performance and lifespan. Attached Figure Description

[0022] Figure 1 This is a top view of Embodiment 1 of the present invention.

[0023] Figure 2 This utility model Figure 1 A schematic diagram of the structure viewed from below;

[0024] Figure 3 This utility model Figure 1 A magnified diagram of part A in the middle;

[0025] Figure 4 This utility model Figure 2 Schematic diagram of the flow channel structure of the first gas reaction zone, the second gas reaction zone, and the third gas reaction zone;

[0026] Figure 5 This utility model Figure 4 A schematic diagram of the structure of a single flow channel in the middle;

[0027] In the diagram: 10. Gas flow channel, 11. First wide diameter region, 12. First gradient region, 13. First narrow diameter region, 14. Second gradient region, 15. Second wide diameter region, 16. Third gradient region, 17. Second narrow diameter region, 18. Fourth gradient region;

[0028] 100. Bipolar plate body; 110. First through hole; 111. First bridge channel; 112. First distribution zone; 113. First gas reaction zone; 120. Second through hole; 121. Second bridge channel; 122. First distribution and collection zone;

[0029] 130. Third through hole, 131. Third bridge passage, 132. Second sub-collection area, 140. Fourth through hole, 141. Fourth bridge passage, 142. Second distribution area;

[0030] 150. Fifth through hole, 151. Fifth bridge channel, 152. Third sub-collection zone, 153. Third gas reaction zone, 160. Sixth through hole, 161. Sixth bridge channel, 162. Third distribution zone. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Example 1

[0033] like Figure 1-2 As shown, this embodiment includes a cathode plate and an anode plate, which are bonded together to form a bipolar plate. A first flow field is provided on the outer side of the cathode plate, a second flow field is provided on the outer side of the anode plate, and a third flow field is formed by the inner sides of the cathode plate and the anode plate being bonded together.

[0034] The first flow field includes a first through-hole 110, a first bridge channel 111, a first distribution zone 112, a first gas reaction zone 113, a first sub-collection zone 122, a second bridge channel 121, and a second through-hole 120, through which gas flows from left to right in sequence. Thus, the first through-hole 110, the first bridge channel 111, the first distribution zone 112, the first gas reaction zone 113, the first sub-collection zone 122, the second bridge channel 121, and the second through-hole 120 constitute an oxidant flow field or a fuel flow field. That is, the oxidant or fuel enters from the first through-hole 110, enters the first distribution zone 112 through the first bridge channel 111, flows to the first gas reaction zone 113 in the first distribution zone 112 and reacts, then enters the first sub-collection zone 122 and converges, and enters the second through-hole 120 through the second bridge channel 121, thereby realizing the flow of the oxidant flow field or the fuel flow field.

[0035] The flow channel length on the first distribution area 112 is the same as the flow channel length on the first sub-collection area 122, and the first through hole 110 and the second through hole 120 are diagonally arranged on the bipolar plate 100; that is, in this embodiment, the first distribution area 112 and the first sub-collection area 122 have the same size and are arranged oppositely.

[0036] The first distribution zone 112 includes several first distribution channels, which are fan-shaped and gradually increase in length from top to bottom. The first sub-collection zone 122 includes several first sub-collection channels, which are fan-shaped and gradually decrease in length from top to bottom.

[0037] In this embodiment, several flow channels in the first distribution area 112 are arc-shaped flow channels, with the length of the flow channels gradually increasing from top to bottom; several flow channels in the first sub-collection area 122 are arc-shaped flow channels, with the length of the flow channels gradually decreasing from bottom to top.

[0038] That is, the longest flow channel in the first distribution zone 112 is connected to the shortest flow channel in the first sub-collection zone 122 through the first gas reaction zone 113; the shortest flow channel in the first distribution zone 112 is connected to the longest flow channel in the first sub-collection zone 122 through the first gas reaction zone 113; and so on, the second longest flow channel in the first distribution zone 112 is connected to the second shortest flow channel in the first sub-collection zone 122 through the first gas reaction zone 113; and the second shortest flow channel in the first distribution zone 112 is connected to the second longest flow channel in the first sub-collection zone 122 through the first gas reaction zone 113. This ensures that the length of each flow channel from the inlet to the outlet is equal. This makes the gas reaction time in each flow channel within the reaction zone tend to be consistent, resulting in consistent power generation throughout the reaction zone, ultimately leading to stable fuel cell power output and improved performance and lifespan.

[0039] The second flow field includes the sixth through-hole 160, the sixth bridge channel 161, the third distribution zone 162, the third gas reaction zone 153, the third sub-collection zone 152, the fifth bridge channel 151, and the fifth through-hole 150, through which gas flows from right to left. Thus, the fifth through-hole 150, the fifth bridge channel 151, the third sub-collection zone 152, the third gas reaction zone 153, the third distribution zone 162, the sixth bridge channel 161, and the sixth through-hole 160 constitute the oxidant flow field or the fuel flow field. That is, the oxidant or fuel enters from the sixth through-hole 160, enters the third distribution zone 162 through the sixth bridge channel 161, flows to the third gas reaction zone 153 in the third distribution zone 162 and reacts, then enters the third sub-collection zone 152 and converges, and enters the fifth through-hole 150 through the fifth bridge channel 151, thus realizing the flow of the oxidant flow field or the fuel flow field.

[0040] The flow channel length on the third sub-collection area 152 is the same as the flow channel length on the third distribution area 162, and the fifth through hole 150 and the sixth through hole 160 are diagonally arranged on the bipolar plate 100; in this embodiment, the third sub-collection area 152 and the third distribution area 162 have the same size and are arranged oppositely.

[0041] In this embodiment, the flow channel of the third distribution zone 162 is an arc-shaped flow channel, which gradually becomes longer from top to bottom; the flow channel of the third sub-collection zone 152 is an arc-shaped flow channel, which gradually becomes longer from bottom to top.

[0042] The third sub-gathering zone 152 includes several third sub-gathering channels, which are fan-shaped and gradually increase in length from top to bottom. The third distribution zone 162 includes several third distribution channels, which are fan-shaped and gradually decrease in length from top to bottom.

[0043] That is, the longest flow channel in the third sub-collection zone 152 is connected to the shortest flow channel in the third distribution zone 162 through the third gas reaction zone 153; the shortest flow channel in the third sub-collection zone 152 is connected to the longest flow channel in the third sub-collection zone 162 through the third gas reaction zone 153; and so on, the second longest flow channel in the third sub-collection zone 152 is connected to the second shortest flow channel in the third distribution zone 162 through the third gas reaction zone 153; and the second shortest flow channel in the third sub-collection zone 152 is connected to the second longest flow channel in the third distribution zone 162 through the third gas reaction zone 153. This ensures that the length of each flow channel from the inlet to the outlet is equal. This makes the gas reaction time in each flow channel within the reaction zone tend to be consistent, resulting in consistent power generation throughout the reaction zone, ultimately leading to stable fuel cell power output and improved performance and lifespan.

[0044] The third flow field includes the third through-hole 130, the third bridge channel 131, the second sub-collection zone 132, the second gas reaction zone, the second distribution zone 142, the fourth bridge channel 141, and the fourth through-hole 140, through which the liquid flows from left to right in sequence. Thus, the third through-hole 130, the third bridge channel 131, the second distribution zone 142, the second gas reaction zone 133, the second sub-collection zone 132, the fourth bridge channel 141, and the fourth through-hole 140 constitute the coolant flow field; that is, the coolant enters from the third through-hole 130, passes through the third bridge channel 131, flows into the second gas reaction zone 133 and reacts there, then enters the second sub-collection zone 132 and converges, and finally flows through the fourth bridge channel 141 to the fourth through-hole 140, thus realizing the flow of the coolant.

[0045] In this embodiment, the third flow field is the coolant flow field in the bipolar plate, which is formed by the inner surfaces of the cathode plate and the anode plate being in contact with each other; the flow structure of the coolant flow field in the bipolar plate is existing technology.

[0046] The flow channel length on the second distribution area 142 is the same as the flow channel length on the second sub-collection area 132. In this embodiment, the second distribution area 142 and the second sub-collection area 132 have the same size but are arranged oppositely.

[0047] The second distribution zone 142 includes several second distribution channels, which are fan-shaped and gradually increase in length from top to bottom. The second sub-collection zone 132 includes several second sub-collection channels, which are fan-shaped and gradually decrease in length from top to bottom.

[0048] The flow channel of the second distribution zone 142 is an arc-shaped flow channel, which gradually becomes longer from top to bottom; the flow channel of the second sub-collection zone 132 is an arc-shaped flow channel, which gradually becomes shorter from bottom to top.

[0049] That is, the longest flow channel in the second distribution zone 142 is connected to the shortest flow channel in the second sub-collection zone 132 through the second gas reaction zone 133; the shortest flow channel in the second distribution zone 142 is connected to the longest flow channel in the second sub-collection zone 132 through the second gas reaction zone 133, and so on. The second longest flow channel in the second distribution zone 142 is connected to the second shortest flow channel in the second sub-collection zone 132 through the second gas reaction zone 133; the second shortest flow channel in the second distribution zone 142 is connected to the second longest flow channel in the second sub-collection zone 132 through the second gas reaction zone 133. This ensures that the length of each flow channel from the inlet to the outlet is equal. This makes the gas reaction time in each flow channel within the reaction zone tend to be consistent, resulting in consistent power generation throughout the reaction zone, ultimately leading to stable fuel cell power output and improved performance and lifespan.

[0050] In this embodiment, the first through hole 110, the third through hole 130, and the fifth through hole 150 are all disposed at the first end 101 of the bipolar plate body 100; the second through hole 120, the fourth through hole 140, and the sixth through hole 160 are all disposed at the second end 102 of the bipolar plate body 100.

[0051] The third through hole 130 is disposed between the first through hole 110 and the fifth through hole 150, and the fourth through hole 140 is disposed between the sixth through hole 160 and the second through hole 120.

[0052] In this embodiment, the first through hole 110 and the second through hole 120 have the same size; the third through hole 130 and the fourth through hole 140 have the same size; and the fifth through hole 150 and the sixth through hole 160 have the same size.

[0053] In one embodiment, the dimensions of the first through hole 110 and the second through hole 120 are larger than the dimensions of the fifth through hole 150 and the sixth through hole 160; that is, the first through hole 110 and the second through hole 120 are hexagonal through holes, the fifth through hole 150 and the sixth through hole 160 are also hexagonal through holes, and thus the aperture of the first through hole 110 and the second through hole 120 is larger than the aperture of the fifth through hole 150 and the sixth through hole 160.

[0054] like Figure 3-5As shown, the first gas reaction zone 113, the second gas reaction zone 133, and the third gas reaction zone 153 each include a plurality of gas flow channels 10. The cross-sectional area of ​​each gas flow channel 10 changes periodically along the gas flow direction. Each cross-sectional area change period of the gas flow channel 10 includes a first wide diameter zone 11, a first gradient zone 12, a first narrow diameter zone 13, a second gradient zone 14, a second wide diameter zone 15, a third gradient zone 16, a second narrow diameter zone 17, and a fourth gradient zone 18 connected in sequence. In this embodiment, the first gradient zone 12, the first narrow diameter zone 13, and the second gradient zone 14 are mirror images of the third gradient zone 16, the second narrow diameter zone 17, and the fourth gradient zone 18. The first wide diameter zone 11 and the second wide diameter zone 15 are not on the same horizontal line; that is, from the perspective of cross-sectional area, the first wide diameter zone 11 is located above one end of the second wide diameter zone 15.

[0055] The cross-sectional area of ​​the first wide diameter region 11 is a direct flow channel along the gas flow direction. In this embodiment, the first wide diameter region 11 is cylindrical. It should be noted that under the same operating conditions (same pressure / flow rate and temperature), the larger the flow channel area, the lower the flow velocity. When the gas passes through the first wide diameter region 11, its flow velocity is the lowest because the first wide diameter region 11 is in the range with the largest flow channel area in the entire flow channel cycle.

[0056] The cross-sectional area of ​​the first gradient region 12 is arc-shaped along the gas flow direction and the diameter gradually decreases; in this embodiment, the cross-sectional area of ​​the first gradient region 12 is arc-shaped along the gas flow direction and the diameter gradually decreases; and the maximum diameter end of the first gradient region 12 is connected to the first wide diameter region 11, and the minimum diameter of the first gradient region 12 is half the diameter of the first wide diameter region 11.

[0057] Therefore, after the gas from the first wide diameter region 11 enters the first gradual transition region 12, the flow velocity begins to increase. As the diameter of the first wide diameter region 11 gradually decreases, the gas flow velocity increases, and the force exerted on the two side walls of the first wide diameter region 11 also increases accordingly, until it enters the narrow diameter region 13.

[0058] The cross-sectional area of ​​the first narrow diameter region 13 is inclined downward along the gas flow direction and the diameter remains unchanged; in this embodiment, the front end of the first narrow diameter region 13 is connected to the minimum diameter in the first gradient region 12, that is, the diameter of the first narrow diameter region 13 is one-half the diameter of the first wide diameter region 11.

[0059] Therefore, when the gas in the first gradient zone 12 enters the first narrow diameter zone 13, the gas velocity in the first narrow diameter zone 13 reaches its maximum because the cross-sectional area of ​​the first narrow diameter zone 13 is inclined downward along the gas flow direction and the diameter remains unchanged; at the same time, the diameter of the first narrow diameter zone 13 is also the smallest.

[0060] The cross-sectional area of ​​the second gradient region 14 is arc-shaped along the gas flow direction and the diameter gradually increases. In this embodiment, the cross-sectional area of ​​the second gradient region 14 is arc-shaped along the gas flow direction and the diameter gradually increases; and the minimum diameter end of the first gradient region 12 is connected to the first narrow diameter region 13, and the minimum diameter of the second gradient region 14 is half the diameter of the first wide diameter region 11.

[0061] The cross-sectional area of ​​the second wide-diameter region 15 is a direct-flow channel along the gas flow direction; in this embodiment, the second wide-diameter region 15 is cylindrical; the front end of the second wide-diameter region 15 is connected to the maximum diameter end of the second gradient region 14; thus, after passing through the second gradient region 14, the gas enters the second wide-diameter region 15; since the gas enters the second gradient region 14 of the same diameter after passing through the first narrow-diameter region 13 for a short period of time, the gas flow velocity also decreases as the area of ​​the second gradient region 14 increases. After passing through the second gradient region 14, the gas enters the same second gradient region 14 as the first gradient region 12, at which point the gas flow velocity reaches its minimum.

[0062] The cross-sectional area of ​​the third gradient region 16 is arc-shaped along the gas flow direction and the diameter gradually decreases; in this embodiment, the cross-sectional area of ​​the third gradient region 16 is arc-shaped along the gas flow direction and the diameter gradually decreases; and the end of the third gradient region 16 with the largest diameter is connected to the end of the second wide diameter region 15, and the minimum diameter of the third gradient region 16 is half the diameter of the second wide diameter region 15.

[0063] Therefore, after the gas enters the third gradient region 16 from the second wide diameter region 15, the flow velocity begins to increase. As the diameter of the third gradient region 16 gradually decreases, the gas flow velocity becomes larger and larger, and the force on the two side walls of the third gradient region 16 also increases accordingly, until it enters the second narrow diameter region 17.

[0064] The cross-sectional area of ​​the second narrow diameter region 17 is inclined upward along the gas flow direction and the diameter remains unchanged; in this embodiment, the front end of the second narrow diameter region 17 is connected to the minimum diameter in the third gradient region 16; the diameter of the second narrow diameter region 17 is half the diameter of the second wide diameter region 15.

[0065] Therefore, when the gas in the third gradient zone 16 enters the second narrow diameter zone 17, the cross-sectional area of ​​the second narrow diameter zone 17 is inclined downward along the gas flow direction and the diameter remains unchanged; at the same time, the diameter of the second narrow diameter zone 17 is also the smallest. Therefore, the gas flow velocity entering the second narrow diameter zone 17 reaches the maximum.

[0066] The cross-sectional area of ​​the fourth gradient region 18 is arc-shaped along the gas flow direction and the diameter gradually increases; in this embodiment, the cross-sectional area of ​​the fourth gradient region 18 is arc-shaped along the gas flow direction and the diameter gradually increases; and the minimum diameter end of the fourth gradient region 18 is connected to the end of the second narrow diameter region 17, and the minimum diameter of the second narrow diameter region 17 is half the diameter of the first wide diameter region 11.

[0067] After passing through the short-length second narrow-diameter zone 17, the gas enters the same fourth gradual transition zone 18 connected to it. At this time, the flow channel area increases from small to large, and the gas flow velocity also decreases from high to low.

[0068] Thus, the entire flow channel circulates continuously, with the gas flow rate fluctuating between fast and slow. Consequently, the flow channel of this application can change the gas flow rate within the flow channel, enhancing the gas diffusion rate to the diffusion layer, which is beneficial for the gas to be evenly distributed and diffused to the gas diffusion layer of the membrane electrode to react with the catalyst. This allows for more efficient and full utilization of the reactants in the gas, while also enhancing the drainage performance within the flow channel.

[0069] Furthermore, fuel cells require the continuous consumption of hydrogen and oxygen ions from the gas within the flow channel during operation. However, the purity of hydrogen or oxygen in the supplied hydrogen and air cannot reach 100% (especially in the cathode flow channel where oxygen ions are drawn from the air). This causes the gas concentration within the flow channel to vary from inlet to outlet, with uneven distribution near the outlet. Simultaneously, the generation of liquid water within the flow channel during fuel cell operation hinders gas flow and diffusion, resulting in insufficient reactants (hydrogen or oxygen ions) in certain areas of the fuel cell, thus affecting the stack's power generation efficiency. This application effectively alleviates this situation, resulting in a more uniform gas distribution and smoother moisture removal.

[0070] In addition, the bipolar plate body 100 has two rings of bosses of the same height as the flow channel along its outer shape and the gas port to accommodate the sealing material for sealing the metal bipolar plate. Four through holes are provided at each of the two ends to facilitate precise positioning of the cathode and anode plates. Furthermore, four "bow"-shaped bosses protruding towards the oxidant flow field side of the cathode plate are provided outside the four positioning holes of the anode plate, and four bosses protruding towards the coolant flow field side of the anode plate and fitting into the cathode plate are provided outside the four positioning holes of the anode plate, to further facilitate more precise positioning of the cathode and anode plates.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the technical solutions of this utility model have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of this utility model.

Claims

1. A bipolar plate for a fuel cell, comprising a cathode plate and an anode plate, wherein the cathode plate and the anode plate are bonded together to form the bipolar plate, a first flow field is disposed on the outer side of the cathode plate, a second flow field is disposed on the outer side of the anode plate, and a third flow field is formed by the inner sides of the cathode plate and the anode plate being bonded together; characterized in that: The first flow field includes a first through hole (110), a first bridge channel (111), a first distribution zone (112), a first gas reaction zone (113), a first sub-collection zone (122), a second bridge channel (121), and a second through hole (120) through which gas flows from left to right in sequence. The length of the flow channel on the first distribution zone (112) is the same as the length of the flow channel on the first sub-collection zone (122). The second flow field includes the sixth through hole (160), the sixth bridge channel (161), the third distribution zone (162), the third gas reaction zone (153), the third sub-collection zone (152), the fifth bridge channel (151), and the fifth through hole (150) through which the gas flows from right to left in sequence. The length of the flow channel on the third sub-collection zone (152) is the same as the length of the flow channel on the third distribution zone (162). The third flow field includes the third through hole (130), the third bridge channel (131), the second sub-collection zone (132), the second gas reaction zone, the second distribution zone (142), the fourth bridge channel (141), and the fourth through hole (140) through which the liquid flows from left to right in sequence. The flow channel length on the second distribution zone (142) is the same as the flow channel length on the second sub-collection zone (132).

2. The fuel cell bipolar plate according to claim 1, characterized in that: The first distribution area (112) includes several first distribution channels, which are fan-shaped and gradually increase in length from top to bottom. The first sub-collection area (122) includes several first sub-collection channels, which are fan-shaped and gradually decrease in length from top to bottom. The third sub-collection area (152) includes several third sub-collection channels, which are fan-shaped and gradually increase in length from top to bottom. The third distribution area (162) includes several third distribution channels, which are fan-shaped and gradually decrease in length from top to bottom.

3. The fuel cell bipolar plate according to claim 1, characterized in that: The third through hole (130) is disposed between the first through hole (110) and the fifth through hole (150); the fourth through hole (140) is disposed between the sixth through hole (160) and the second through hole (120).

4. The fuel cell bipolar plate according to claim 1, characterized in that: The first through hole (110) and the second through hole (120) are diagonally disposed on the bipolar plate (100); the fifth through hole (150) and the sixth through hole (160) are diagonally disposed on the bipolar plate (100).

5. The fuel cell bipolar plate according to claim 1, characterized in that: The dimensions of the first through hole (110) and the second through hole (120) are larger than the dimensions of the fifth through hole (150) and the sixth through hole (160).

6. The fuel cell bipolar plate according to claim 4, characterized in that: The first gas reaction zone (113), the second gas reaction zone (133), and the third gas reaction zone (153) each include several gas flow channels (10), and the cross-sectional area of ​​each gas flow channel (10) changes periodically along the gas flow direction.

7. The fuel cell bipolar plate according to claim 6, characterized in that: Each cross-sectional area change cycle of the gas flow channel (10) includes a first wide diameter region (11), a first gradient region (12), a first narrow diameter region (13), a second gradient region (14), a second wide diameter region (15), a third gradient region (16), a second narrow diameter region (17), and a fourth gradient region (18) connected in sequence. The cross-sectional area of ​​the first narrow diameter region (13) is inclined downward along the gas flow direction and its diameter remains unchanged. The cross-sectional area of ​​the second narrow diameter region (17) is inclined upward along the gas flow direction and its diameter remains unchanged.

8. The fuel cell bipolar plate according to claim 7, characterized in that: The first gradient area (12), the first narrow diameter area (13), the second gradient area (14) are mirror images of the third gradient area (16), the second narrow diameter area (17), and the fourth gradient area (18).

9. The fuel cell bipolar plate according to claim 8, characterized in that: The first wide diameter region (11) and the second wide diameter region (15) are not on the same horizontal line.

10. The fuel cell bipolar plate according to claim 9, characterized in that: The cross-sectional area of ​​the first wide diameter region (11) is a direct current channel along the gas flow direction; the cross-sectional area of ​​the first gradient region (12) is arc-shaped along the gas flow direction and its diameter gradually decreases; the cross-sectional area of ​​the second gradient region (14) is arc-shaped along the gas flow direction and its diameter gradually increases; the cross-sectional area of ​​the second wide diameter region (15) is a direct current channel along the gas flow direction; the cross-sectional area of ​​the third gradient region (16) is arc-shaped along the gas flow direction and its diameter gradually decreases; the cross-sectional area of ​​the fourth gradient region (18) is arc-shaped along the gas flow direction and its diameter gradually increases.

Images