A fuel cell bipolar plate flow field structure

Abstract

The present invention relates to the field of fuel cell technology, and discloses a fuel cell bipolar plate flow field structure, comprising a substrate, an anode plate, and a cathode plate. The substrate is provided with an anode plate, and a cathode plate is provided below the anode plate. A fuel gas inlet is provided at one end above the substrate, and an oxygen outlet is provided at the other end above the substrate. A coolant inlet is provided below the fuel gas inlet, and an oxygen inlet is provided below the coolant inlet. The present invention provides a plurality of guide plates, fuel gas flow channels, a rough layer, and a plurality of windshields in the flow field area, so that when the gas encounters the rough layer and the windshields, the gas flow rate is reduced and the gas pressure is increased, pushing the gas in the flow channel toward the membrane electrode to participate in the electrochemical reaction in the fuel cell. When the gas continues to move between the parallel plates, the gas flow is unobstructed, the gas pressure is reduced, and the pressure difference between the inlet and the outlet is reduced, thereby enhancing the mass transfer capacity within the fuel cell.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, in particular to a bipolar plate flow field structure for a fuel cell. Background Art

[0002] Fuel cells, as zero-pollution, high-efficiency power generation devices that directly convert the chemical energy of fuel into electrical energy, are increasingly being used in numerous applications, including transportation vehicles, distributed power stations, and portable power supplies. They offer high power density, high energy conversion efficiency, fast start-up at room temperature, low environmental pollution, and flexibility. The key components of fuel cells are the membrane electrode and bipolar plate (BEP). The BEP is the core component of fuel cells, and the proper design of the BEP flow path directly impacts the performance and lifespan of the fuel cell stack. Common BEP flow field configurations include serpentine, parallel, and interdigitated. These novel flow fields can enhance mass transfer within PEMFCs, but their main drawbacks are high pressure drop and complex fabrication. Parallel flow, with its low pressure drop and ease of fabrication, is currently the most widely used flow field configuration. By adding a block, the reactant gases are forced into the diffusion layer while also facilitating the removal of generated water. This improves mass transfer, mitigates the effects of concentration polarization, and enhances PEMFC performance. However, this method will cause a huge pressure drop difference, resulting in additional energy consumption, and the gas in the parallel flow field is not uniform enough. Therefore, a fuel cell bipolar plate flow field structure is proposed.

[0003] A Chinese patent discloses a fuel cell bipolar plate flow field structure (authorization announcement number CN107681174A). The patented technology includes an anode flow field, a cathode flow field and a cooling flow field. The cooling flow field is located between the anode flow field and the cathode flow field. The cooling flow field includes half of the cooling channels located in the first layer and the other half of the cooling channels located in the second layer. Half of the cooling channels are arranged along the gaps of the anode channels that constitute the anode flow field and are arranged alternately with the anode channels. The other half of the cooling channels are arranged along the gaps of the cathode channels that constitute the cathode flow field and are arranged alternately with the cathode channels. This design arrangement is conducive to full contact between the cooling medium in the cooling flow field and the reactor stack; both the anode flow field and the cathode flow field adopt serpentine flow fields to increase the length of the flow channels. The serpentine flow field is provided with at least one serpentine flow channel, which can In order to limit the formation of turbulence in the process of gas transmission from the air inlet to the reaction zone, the gas transmission area in the serpentine flow field is smaller and the distance is longer, the gas flow rate in the flow field is larger, and the pressure difference between the inlet and the outlet is also larger, which is beneficial to the discharge of water generated by the reaction in the fuel cell and avoids flow channel blockage; while increasing the area of ​​the flow field reaction zone in the bipolar plate as much as possible, the number of serpentine flow channels is reasonably designed to reduce the pressure drop and gas transmission resistance as much as possible, make the gas distribution uniform, increase the power density of the fuel cell, and enhance the power generation performance of the fuel cell. However, the gas or liquid flow process is not uniform enough, and there is a pressure difference between the inlet and outlet, which affects the normal use of the device. In addition, the flow rate of the coolant inside the device is relatively slow, the flow is not smooth enough, and the problem of local overtemperature may easily occur. Summary of the Invention

[0004] The object of the present invention is to provide a bipolar plate flow field structure for a fuel cell to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A fuel cell bipolar plate flow field structure comprises a substrate, an anode plate and a cathode plate, the anode plate being arranged on the substrate, the cathode plate being arranged below the anode plate, a fuel gas inlet being arranged at one end above the substrate, an oxygen outlet being arranged at the other end above the substrate, a coolant inlet being arranged below the fuel gas inlet, an oxygen inlet being arranged below the coolant inlet, a coolant outlet being arranged below the oxygen outlet, and a fuel gas outlet being arranged below the coolant outlet, a flow field area being arranged in the middle part above the substrate, dispersion areas being arranged on both sides of the flow field area, a plurality of diverter plates being arranged on one side inside the dispersion area, a plurality of bosses being arranged on one side of the diverter plate, the diverter plates and the bosses being staggered, a plurality of guide plates being arranged inside the flow field area, fuel gas flow channels being arranged between the guide plates, a rough layer being arranged between the fuel gas flow channels, and a plurality of wind shields being arranged above the rough layer.

[0007] As a further solution of the present invention: a membrane electrode is provided between the anode plate and the cathode plate, and a protective layer is provided on the outer side of the membrane electrode.

[0008] As a further solution of the present invention: a plurality of fuel gas channels are provided on one side inside the fuel gas inlet and the fuel gas outlet, and a plurality of oxygen channels are provided on one side inside the oxygen inlet and the oxygen outlet.

[0009] As a further solution of the present invention: a plurality of first coolant channels are provided on one side of the coolant inlet, and a plurality of second coolant channels are provided on one side of the coolant outlet, wherein the diameter of the second coolant channels is smaller than that of the first coolant channels.

[0010] As a further solution of the present invention: an arc-shaped plate is provided in the middle of the guide plate, parallel plates are provided on both sides of the arc-shaped plate, and baffles are provided on the base plate near the upper and lower guide plates.

[0011] As a further solution of the present invention: a central cone is provided on the substrate near the inner circle fuel gas flow channel, and the curvature of the arc plate gradually decreases from the central cone to the outside.

[0012] As a further solution of the present invention: a cooling liquid flow channel is provided between the anode plate and the membrane electrode, and an oxygen flow channel is provided between the cathode plate and the membrane electrode.

[0013] As a further solution of the present invention: a plurality of guide bosses are provided inside the coolant flow channel, the guide bosses are inclined at a certain angle, and the surfaces of the guide bosses are provided with a corrosion-resistant coating.

[0014] As a further solution of the present invention: the base materials of the substrate, anode plate and cathode plate can be selected from any one of graphite, titanium alloy and composite graphite resin materials.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. By setting dispersion areas at both ends above the substrate, a flow field area is set between the dispersion areas, and a number of diverter plates and bosses are set inside the dispersion areas, it is convenient to introduce fuel, coolant, and oxygen into the corresponding flow field, and use the diverter plates to quickly disperse and guide the gas or liquid. At the same time, the bosses can be used to evenly distribute the gas or liquid to the surrounding areas, so as to achieve a uniform flow field area, which is conducive to improving the later reaction effect. At the same time, a central cone and a number of guide plates are set inside the flow field area. The guide plates are composed of parallel plates and arc plates. Fuel gas flow channels are set between the guide plates. A rough layer and multiple windshields are provided between the fuel gas flow channels to facilitate the gas to enter the flow field area. When the gas flows from the inlet to the outlet and encounters the rough layer and windshield, the fuel gas flow channel becomes narrower, the gas flow rate decreases, and the gas pressure increases, pushing the gas in the flow channel toward the membrane electrode to participate in the electrochemical reaction in the fuel cell. When the gas continues to move and moves between the parallel plates again, the area of ​​the fuel gas flow channel increases, the gas flow is unobstructed, and the gas pressure is reduced, so that the pressure difference between the inlet and outlet is reduced, thereby enhancing the mass transfer capacity inside the fuel cell.

[0017] 2. By providing a plurality of first cooling liquid channels on one side of the coolant inlet and a plurality of second cooling liquid channels on one side of the coolant outlet, the first cooling liquid channel is larger than the second cooling liquid channel, so that in the process of the coolant entering the cooling liquid flow channel, the diameter of the outlet is smaller than the inlet, thereby increasing the flow rate of the cooling liquid, avoiding the problem of excessive gas flow rate, resulting in insufficient and comprehensive cooling, so that the fuel, oxygen and coolant in the flow field area can move and react in the channel in a consistent manner, and there will be no problem of local concentrated violent reaction. The current density is more uniform, and the problem of excessively high local temperature of the cathode plate and the anode plate will not occur. At the same time, a plurality of guide bosses are provided inside the cooling liquid flow channel, so that the liquid forms a drop during the flow process, the flow of the liquid is more evenly dispersed, and stagnation will not occur, thereby promoting uniform heat exchange between the cathode plate and the anode plate, and the flow of the coolant from the first cooling liquid channel to the second cooling liquid channel is smoother, ensuring the normal use of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a front view of a fuel cell bipolar plate flow field structure;

[0019] Figure 2 for Figure 1 Schematic diagram of the enlarged structure of A;

[0020] Figure 3 for Figure 1 Schematic diagram of the enlarged structure of B;

[0021] Figure 4A partial side cross-sectional view of a fuel cell bipolar plate flow field structure;

[0022] Figure 5 for Figure 4 Side view of the cross section of C in the middle.

[0023] In the figure: 1. Base plate; 2. Fuel gas inlet; 3. Coolant inlet; 4. Oxygen inlet; 5. Fuel gas outlet; 6. Coolant outlet; 7. Oxygen outlet; 8. Fuel gas channel; 9. First coolant channel; 10. Second coolant channel; 11. Diverter plate; 12. Boss; 13. Baffle; 14. Parallel plate; 15. Arc plate; 16. Guide plate; 17. Rough layer; 18. Fuel gas flow channel; 19. Dispersion area; 20. Flow field area; 21. Oxygen channel; 22. Wind shield; 23. Center cone; 24. Anode plate; 25. Cathode plate; 26. Membrane electrode; 27. Protective layer; 28. Oxygen flow channel; 29. ​​Coolant flow channel; 30. Guide boss; 31. Corrosion-resistant coating. DETAILED DESCRIPTION

[0024] See also Figures 1 to 5In an embodiment of the present invention, a bipolar plate flow field structure for a fuel cell includes a substrate 1, an anode plate 24 and a cathode plate 25. The anode plate 24 is provided on the substrate 1, and the cathode plate 25 is provided below the anode plate 24. A fuel gas inlet 2 is provided at one end above the substrate 1, and an oxygen outlet 7 is provided at the other end above the substrate 1. A coolant inlet 3 is provided below the fuel gas inlet 2, an oxygen inlet 4 is provided below the coolant inlet 3, a coolant outlet 6 is provided below the oxygen outlet 7, and a fuel gas outlet 5 is provided below the coolant outlet 6 to facilitate the entry and exit of fuel, coolant and oxygen, thereby achieving sufficient reaction. A flow field area 20 is provided in the middle part above the substrate 1, and dispersion areas 19 are provided on both sides of the flow field area 20. A plurality of diverter plates 11 are provided on one side of the dispersion area 19, and a plurality of bosses 12 are provided on one side of the diverter plate 11. The diverter plates 11 and the bosses 12 are staggered, thereby facilitating the drainage and dispersion of gas or liquid, and facilitating the introduction of fuel, coolant and oxygen into the corresponding flow field. The diverter plate 11 can be used to quickly disperse and drain the gas or liquid, and the boss 12 can be used to evenly distribute the gas or liquid to the surroundings, so that the flow field area 20 can be uniform, which is beneficial to improving the later reaction effect. A number of guide plates 16 are arranged inside the flow field area 20, and fuel gas flow channels 18 are arranged between the guide plates 16. A rough layer 17 is arranged between the fuel gas flow channels 18, and a plurality of windshields 22 are arranged above the rough layer 17 to facilitate the gas entering the flow field area 20. When the fuel gas flow channel 18 is used, when the gas flows from the inlet to the outlet and encounters the rough layer 17 and the windshield 22, the fuel gas flow channel becomes narrower, the gas flow rate decreases, and the gas pressure increases, pushing the gas in the flow channel to the membrane electrode to participate in the electrochemical reaction in the fuel cell. When the gas continues to move and moves between the parallel plates 14 again, the area of ​​the fuel gas flow channel 18 increases, the flow of gas is not blocked, the gas pressure is reduced, and the pressure difference between the inlet and outlet is reduced, thereby enhancing the mass transfer capacity inside the fuel cell.

[0025] exist Figure 4 Middle: A membrane electrode 26 is provided between the anode plate 24 and the cathode plate 25 , providing a microchannel for multiphase material transfer and an electrochemical reaction site for the fuel cell. A protective layer 27 is provided on the outside of the membrane electrode 26 .

[0026] exist Figure 1 Middle: Several fuel gas channels 8 are provided on one side inside the fuel gas inlet 2 and the fuel gas outlet 5, and several oxygen channels 21 are provided on one side inside the oxygen inlet 4 and the oxygen outlet 7 to facilitate the discharge of gas from the respective channels.

[0027] exist Figure 1 and 2Middle: A plurality of first coolant channels 9 are provided on one side of the coolant inlet 3, and a plurality of second coolant channels 10 are provided on one side of the coolant outlet 6. The diameter of the second coolant channel 10 is smaller than that of the first coolant channel 9, and the diameter at the outlet is smaller than that at the inlet, thereby increasing the flow rate of the coolant liquid, avoiding the problem of excessive gas flow rate leading to insufficient and comprehensive cooling, and making the movement and reaction of fuel, oxygen and coolant in the flow field area 20 in the channel tend to be consistent, without the problem of locally concentrated violent reactions, and the current density is more uniform.

[0028] exist Figure 1 and 3 Middle: An arc plate 15 is provided in the middle of the guide plate 16, and parallel plates 14 are provided on both sides of the arc plate 15, which reduces the problem of large resistance in the previous serpentine flow field and reduces the pressure difference of the gas along the flow channel. A baffle 13 is provided on the substrate 1 near the upper and lower guide plates 16.

[0029] exist Figure 1 and 3 Middle: A central cone 23 is provided on the substrate 1 near the inner circle fuel gas flow channel 18. The curvature of the arc plate 15 gradually decreases from the central cone 23 outward, so that the flow path of the gas tends to be consistent during the flow process, thereby ensuring the normal reaction effect in the later stage.

[0030] exist Figure 4 Middle: A coolant flow channel 29 is provided between the anode plate 24 and the membrane electrode 26, and an oxygen flow channel 28 is provided between the cathode plate 25 and the membrane electrode 26 to ensure the normal circulation of the coolant and oxygen, and to ensure the effect of subsequent reactions, so that the fuel, oxygen and coolant in the flow field area 20 can move and react in the channel in a consistent manner, and there will be no problem of local concentrated violent reactions. The current density is more uniform, and there will be no problem of excessive local temperature of the cathode plate 25 and the anode plate 24.

[0031] exist Figure 5 Middle: Several guide bosses 30 are provided inside the coolant flow channel 29. The guide bosses 30 are inclined at a certain angle, so that a drop is formed in the liquid during the flow process. The flow of the liquid is more evenly dispersed and will not cause stagnation, thereby promoting the uniform heat exchange between the cathode plate 25 and the anode plate 24. The flow of the coolant from the first coolant channel 9 to the second coolant channel 10 is smoother, ensuring the normal use of the device. The surface of the guide boss 30 is provided with a corrosion-resistant coating 31, which makes the device less prone to corrosion, thereby increasing the service life of the device.

[0032] exist Figure 1Middle: The base materials of the substrate 1, the anode plate 24 and the cathode plate 25 can be selected from any one of graphite, titanium alloy, and composite graphite resin materials. When the base material is graphite, it can be manufactured by a machine carving molding process. When the base material is a titanium alloy, it can be manufactured by a stamping, rolling, and etching molding process. When the base material is a composite graphite resin material, it can be manufactured by a molding and roll pressing process.

[0033] The working principle of the present invention is as follows: when using the device, a dispersion area 19 is provided at both ends above the substrate 1, a flow field area 20 is provided between the dispersion areas 19, and a plurality of diverter plates 11 and bosses 12 are provided inside the dispersion areas 19, so that after the fuel, coolant, and oxygen are introduced into the corresponding flow field, the diverter plates 11 can be used to quickly disperse and drain the gas or liquid, and the bosses 12 can be used to evenly distribute the gas or liquid to the surrounding areas, thereby achieving a uniform flow field area 20, which is beneficial to improving the later reaction effect. At the same time, a central cone 23 and a plurality of guide plates 1 are provided inside the flow field area 20. 6. The guide plate 16 is composed of a parallel plate 14 and an arc plate 15. A fuel gas flow channel 18 is provided between the guide plates 16. A rough layer 17 and a plurality of windshields 22 are provided between the fuel gas flow channels 18 to facilitate the gas to enter the flow field area 20. When the gas flows from the inlet to the outlet, when it encounters the rough layer 17 and the windshield 22, the fuel gas flow channel becomes narrower, the gas flow rate decreases, and the gas pressure increases, pushing the gas in the flow channel toward the membrane electrode to participate in the electrochemical reaction in the fuel cell. When the gas continues to move and moves between the parallel plates 14 again, the surface of the fuel gas flow channel 18 is The volume is increased, the flow of gas is not blocked, the gas pressure is reduced, and the pressure difference between the inlet and the outlet is reduced, thereby strengthening the mass transfer capacity inside the fuel cell. By providing a plurality of first coolant channels 9 on one side of the coolant inlet 3, and a plurality of second coolant channels 10 on one side of the coolant outlet 6, the first coolant channels 9 are larger than the second coolant channels 10, so that when the coolant enters the coolant flow channel, the diameter of the outlet is smaller than the inlet, thereby increasing the flow rate of the coolant liquid, avoiding the problem that the gas flow rate is too fast and the cooling is not fast and comprehensive, so that the flow field area 20 is fueled. The material, oxygen and coolant can move and react in the channel in a consistent manner, and there will be no problem of local concentrated violent reaction. The current density is more uniform, and there will be no problem of local excessive temperature of the cathode plate 25 and the anode plate 24. At the same time, a plurality of guide bosses 30 are provided inside the coolant flow channel, so that a drop is formed in the liquid during the flow process, and the flow of the liquid is more evenly dispersed without causing stagnation, thereby promoting the uniform heat exchange of the cathode plate 25 and the anode plate 24, and the flow of the coolant from the first coolant channel 9 to the second coolant channel 10 is smoother, thereby ensuring the normal use of the device.

[0034] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A fuel cell bipolar plate flow field structure, comprising a substrate (1), an anode plate (24) and a cathode plate (25), wherein the anode plate (24) is arranged on the substrate (1), and the cathode plate (25) is arranged below the anode plate (24), characterized in that: A fuel gas inlet (2) is provided at one end above the substrate (1), an oxygen outlet (7) is provided at the other end above the substrate (1), a coolant inlet (3) is provided below the fuel gas inlet (2), an oxygen inlet (4) is provided below the coolant inlet (3), a coolant outlet (6) is provided below the oxygen outlet (7), a fuel gas outlet (5) is provided below the coolant outlet (6), a flow field area (20) is provided in the middle portion above the substrate (1), and both sides of the flow field area (20) are provided. A dispersion area (19) is provided, a plurality of diverter plates (11) are provided on one side of the dispersion area (19), a plurality of bosses (12) are provided on one side of the diverter plates (11), the diverter plates (11) and the bosses (12) are arranged in a staggered manner, a plurality of guide plates (16) are provided inside the flow field area (20), fuel gas flow channels (18) are provided between the guide plates (16), a rough layer (17) is provided between the fuel gas flow channels (18), and a plurality of windshield plates (22) are provided above the rough layer (17); An arc-shaped plate (15) is provided in the middle of the guide plate (16), parallel plates (14) are provided on both sides of the arc-shaped plate (15), and baffles (13) are provided on the base plate (1) near the upper and lower guide plates (16); A central truncated cone (23) is provided on the substrate (1) near the inner ring fuel gas flow channel (18), and the curvature of the arc-shaped plate (15) gradually decreases from the central truncated cone (23) outwards.

2. A fuel cell bipolar plate flow field structure according to claim 1, characterized in that: A membrane electrode (26) is provided between the anode plate (24) and the cathode plate (25), and a protective layer (27) is provided on the outside of the membrane electrode (26).

3. A fuel cell bipolar plate flow field structure according to claim 1, characterized in that: A plurality of fuel gas channels (8) are provided on one side of the interior of the fuel gas inlet (2) and the fuel gas outlet (5), and a plurality of oxygen channels (21) are provided on one side of the interior of the oxygen inlet (4) and the oxygen outlet (7).

4. A fuel cell bipolar plate flow field structure according to claim 1, characterized in that: A plurality of first cooling liquid channels (9) are provided on one side of the interior of the cooling liquid inlet (3), and a plurality of second cooling liquid channels (10) are provided on one side of the cooling liquid outlet (6), wherein the diameter of the second cooling liquid channels (10) is smaller than that of the first cooling liquid channels (9).

5. A fuel cell bipolar plate flow field structure according to claim 1, characterized in that: The base materials of the substrate (1), the anode plate (24) and the cathode plate (25) are selected from any one of graphite, titanium alloy and composite graphite resin materials.

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