A bionic self-transporting drainage flow field of a proton exchange membrane fuel cell bipolar plate
Through the design of the bionic self-transportation drainage flow field, the active drainage of the fuel cell is achieved using wedge angles and pit structures, which solves the performance degradation caused by flooding and improves the stability and efficiency of the fuel cell.
Patent Information
- Application Number
- CN202010978457.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-09-17
- Publication Date
- 2024-12-20
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The "water flooding" phenomenon caused by water accumulation during the operation of the proton exchange membrane fuel cell hinders oxygen transmission, resulting in performance degradation and output voltage fluctuations. The existing purge and drainage methods are inefficient and increase the transmission resistance of the reaction gas, affecting stability. .
A bionic self-transportation drainage flow field was designed, using the liquid self-transportation function on the oral edge surface of Nepenthes and the pit structure on the surface of biological bodies. The liquid reflux is reduced through wedge angles and pits, and the active drainage is achieved and the reaction is reduced. Gas flow resistance, enhance drainage effect.
It realizes spontaneous active drainage, reduces the input power of reaction gas, improves the performance and stability of fuel cells, and lays the foundation for the widespread application of fuel cell vehicles.
Smart Images
Figure CN112186215B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of proton exchange membrane fuel cells, in particular to a bionic self-transport drainage flow field of a bipolar plate of a proton exchange membrane fuel cell. Background Art
[0002] Fuel cells are the fourth generation of power generation technology after thermal power, hydropower and nuclear power. As the most studied of fuel cells, proton exchange membrane fuel cells (PEMFC) are very suitable as a power source for electric vehicles due to their outstanding advantages such as low operating temperature, small size, short start-up time, high specific power, simple structure and easy operation.
[0003] However, during the normal operation of PEMFC, as the chemical reaction continues, the water generated on the cathode side continues to accumulate. If it cannot be discharged in time, serious "flooding" will occur. As the "flooding" phenomenon becomes more and more serious, the cathode flow channel is blocked, which seriously hinders the oxygen transmission, resulting in insufficient oxygen supply and increased concentration polarization, which leads to a sharp decline in the performance of PEMFC. In addition, under constant current density, the "flooding" phenomenon will cause a large fluctuation in the output voltage, affecting the stability of PEMFC performance.
[0004] The current drainage method basically relies on the originally introduced reaction gas (air or oxygen) to blow the water in the flow channel to the outlet, and its effect is completely limited by the structure and geometric dimensions of the flow field. Moreover, this passive purge drainage method greatly increases the transmission resistance of the reaction gas, and the effect is not satisfactory; on the other hand, improving the drainage effect by intermittently increasing the gas flow rate will seriously affect the stability of PEMFC performance, greatly limiting its application and development. Summary of the invention
[0005] In view of the technical problems existing in the prior art, the purpose of the present invention is to provide a bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate, break through the drainage limit of the traditional purge method, realize a truly spontaneous active drainage function, reduce the input power of the reaction gas, make the reaction more uniform, improve the performance and stability of the proton exchange membrane fuel cell, and lay the foundation for its further widespread application in fuel cell vehicles.
[0006] In order to achieve the above object, the present invention adopts the following technical solution:
[0007] A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate comprises a flow field body, wherein a reaction gas inlet and a reaction gas outlet are respectively arranged at both ends of the flow field body, a plurality of flow channels are arranged between the reaction gas inlet and the reaction gas outlet, a plurality of transport blocks are arranged in sequence in each flow channel, and a front transport block and a rear transport block are arranged in sequence in each transport block along the reaction gas flow direction, a gap is arranged between the front transport block and the rear transport block, a pit is formed between the front transport block and the rear transport block, the cross section of the rear transport block gradually decreases from top to bottom, the rear transport block is provided with a corresponding first side wall and a second side wall, the first side wall is arranged between the front transport block and the second side wall, a first recessed portion is arranged in the middle of the first side wall, a first protrusion is arranged in the middle of the second side wall, the directions of the first protrusion and the first recessed portion are both the same as the reaction gas flow direction, and the second side wall is perpendicular to the surface of the flow field body.
[0008] Furthermore, the front transport block is provided with corresponding third side walls and fourth side walls, a second protrusion is provided in the middle of the third side wall, a second recess is provided in the middle of the fourth side wall, the second recess is provided between the second protrusion and the rear transport block, and the directions of the second protrusion and the second recess are opposite to the flow direction of the reaction gas.
[0009] Furthermore, the third side wall and the fourth side wall are both perpendicular to the surface of the flow field body.
[0010] Furthermore, the second side wall, the third side wall and the fourth side wall are all arc surfaces, and the first side wall is a curved surface.
[0011] Furthermore, the areas of the upper end surface and the lower end surface of the front transport block are equal.
[0012] Furthermore, the plurality of transport blocks are arranged in two or more rows in the flow channel.
[0013] Furthermore, the flow field body and the transport block are both made of stainless steel.
[0014] Furthermore, the flow field body is a parallel flow field.
[0015] Furthermore, the flow field body is a serpentine flow field.
[0016] Furthermore, the flow field body is an interdigital flow field.
[0017] In general, the present invention has the following advantages:
[0018] The wedge angle formed between the first side wall and the flow channel can enable the liquid to fill quickly along the flow direction under the capillary action, thereby realizing a truly spontaneous active drainage function.
[0019] When the liquid flows through the second side wall, the second side wall will not restrict the flow of the liquid, thereby facilitating the maintenance of the forward flow of the liquid.
[0020] The pit formed between the front transport block and the rear transport block is beneficial to reducing the flow resistance of the reaction gas, making the reaction in the flow field more uniform. At the same time, since the reaction gas flows more actively, it has the effect of accelerating the liquid transport speed.
[0021] It breaks through the drainage limit of traditional purge methods, realizes the spontaneous and truly active drainage function, reduces the input power of the reaction gas, makes the reaction more uniform, improves the performance and stability of proton exchange membrane fuel cells, and lays the foundation for its further widespread application in fuel cell vehicles. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic diagram of a flow channel according to an embodiment of the present invention having a single row of transport blocks arranged therein.
[0023] Figure 2 A schematic diagram of a flow channel according to an embodiment of the present invention having double rows of transport blocks.
[0024] Figure 3 It is a schematic diagram of an embodiment of the present invention applied to a parallel flow field.
[0025] Figure 4 It is a schematic diagram of an embodiment of the present invention applied to a serpentine flow field.
[0026] Figure 5 It is a schematic diagram of an embodiment of the present invention applied to an interdigital flow field.
[0027] Description of reference numerals:
[0028] 1——rear transport block, 2——front transport block, 3——pit, 4——reaction gas inlet, 5——reaction gas outlet. DETAILED DESCRIPTION
[0029] The present invention will be described in further detail below.
[0030] Many animal and plant surfaces in nature have directional liquid transport functions, such as spider silk, cactus, shorebirds, desert beetles, butterfly wings and pitcher plants, and their bionic structures have broad application prospects in many chemical processes such as heat transfer, separation, and microfluidics. Among them, the surface of the rim of the pitcher plant has a stable self-transport function for droplets, liquid films, and liquid columns. In addition, people's research on bionics has found that the surfaces of many organisms such as dung beetles and pangolins show non-smooth structures such as convex hulls, pits 3, and ridges. This non-smooth surface has a drag reduction effect when flying in the air and swimming in the water. The embodiment of the present invention applies the liquid self-transport function of the rim surface of the pitcher plant and the drag reduction effect of the pits 3 on the gas in the design of the flow field structure of the bipolar plate of the proton exchange membrane fuel cell, which is expected to break through the drainage limit of the traditional purge method and achieve a more efficient drainage function, thereby improving the performance and stability of the proton exchange membrane fuel cell, and laying a foundation for its further extensive application in fuel cell vehicles.
[0031] like Figure 1 , Figure 2 As shown, a bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate comprises a flow field body, wherein a reaction gas inlet 4 and a reaction gas outlet 5 are respectively arranged at both ends of the flow field body, a plurality of flow channels are arranged between the reaction gas inlet 4 and the reaction gas outlet 5, and each flow channel is sequentially provided with a plurality of transport blocks, and each transport block is sequentially provided with a front transport block 2 and a rear transport block 1 along the flow direction of the reaction gas, a gap is arranged between the front transport block 2 and the rear transport block 1, a pit 3 is formed between the front transport block 2 and the rear transport block 1, the cross section of the rear transport block 1 gradually decreases from top to bottom, and the rear transport block 1 is provided with a corresponding first side wall and a second side wall, the first side wall is arranged between the front transport block 2 and the second side wall, a first recessed portion is arranged in the middle of the first side wall, and a first protrusion is arranged in the middle of the second side wall, the directions of the first protrusion and the first recessed portion are both the same as the flow direction of the reaction gas, and the second side wall is perpendicular to the surface of the flow field body.
[0032] Since the cross section of the rear transport block 1 gradually decreases from top to bottom, and the first recessed portion provided in the middle of the first side wall is in the same direction as the flow direction of the reaction gas, the angle between the first recessed portion of the first side wall and the flow channel surface forms a wedge angle less than 90 degrees. According to the principle of liquid self-transportation on the surface of the rim of the pitcher plant, before the liquid on the flow channel reaches force balance, the wedge angle formed between the first side wall and the flow channel can enable the liquid to fill quickly along the flow direction under the capillary action, thus realizing a truly spontaneous active drainage function.
[0033] The second side wall is perpendicular to the surface of the flow field body. According to the Gibbs inequality condition, when the liquid flows through the second side wall, the second side wall will not restrict the movement of the liquid, thereby facilitating the maintenance of the forward flow of the liquid.
[0034] The design of the body surface of organisms such as dung beetles and pangolins is imitated, and the pit 3 formed between the front transport block 2 and the rear transport block 1 is conducive to reducing the flow resistance of the reaction gas, making the reaction in the flow field more uniform, and at the same time, because the reaction gas flows more actively, it has the effect of accelerating the liquid transport speed. The gap set between the front transport block 2 and the rear transport block 1 prevents the liquid from flowing back to the front transport block 2 from the first recessed portion of the first side wall.
[0035] The embodiment of the present invention imitates the special periodic duckbill-shaped microcavity structure with arched edges on the surface of the rim of the pitcher plant, and combines the drag reduction characteristics of the bionic non-smooth pit 3 surface, breaking through the drainage limit of the traditional purge method, realizing a truly spontaneous active drainage function, reducing the input power of the reaction gas, making the reaction more uniform, and improving the performance and stability of the proton exchange membrane fuel cell, laying a foundation for its further widespread application in fuel cell vehicles.
[0036] The front transport block 2 is provided with corresponding third and fourth side walls, a second protrusion is provided in the middle of the third side wall, a second recess is provided in the middle of the fourth side wall, the second recess is provided between the second protrusion and the rear transport block, and the directions of the second protrusion and the second recess are opposite to the flow direction of the reaction gas.
[0037] The direction of the second recessed portion of the front transport block 2 is opposite to the flow direction of the reaction gas, and a relatively large pit 3 is formed between the second recessed portion and the first recessed portion of the rear transport block 1, thereby reducing the flow resistance of the reaction gas.
[0038] The third side wall and the fourth side wall are both perpendicular to the surface of the flow field body. According to the Gibbs inequality condition, when the liquid flows through the front transport block 2, the transport block 2 will not restrict the flow of the liquid.
[0039] With this structure, the front transport block 2 is easier to manufacture.
[0040] The second side wall, the third side wall and the fourth side wall are all arc surfaces, and the first side wall is a curved surface.
[0041] The curved surface design of the first side wall can form a wedge angle with a variable angle between the first side wall and the flow channel surface, thereby generating capillary force to drive the liquid to flow forward spontaneously.
[0042] The areas of the upper end surface and the lower end surface of the front transport block 2 are equal.
[0043] The upper end surface and the lower end surface of the front transport block 2 are both planes and parallel to each other, so the front transport block 2 is easier to manufacture.
[0044] The plurality of transport blocks are arranged in two or more rows in the flow channel.
[0045] Multiple transport blocks are arranged in multiple rows, which enhances the active drainage capability of the flow channel and improves the drainage effect.
[0046] The flow field body and the transport block are made of stainless steel.
[0047] like Figure 3 As shown, the flow field body is a parallel flow field.
[0048] like Figure 4 As shown, the flow field body is a serpentine flow field.
[0049] like Figure 5 As shown, the flow field body is an interdigital flow field.
[0050] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.
Claims
1. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate, Features: It comprises a flow field body, wherein a reaction gas inlet and a reaction gas outlet are respectively arranged at two ends of the flow field body, a plurality of flow channels are arranged between the reaction gas inlet and the reaction gas outlet, a plurality of transport blocks are arranged in sequence in each flow channel, a front transport block and a rear transport block are arranged in sequence along the flow direction of the reaction gas, a gap is arranged between the front transport block and the rear transport block, a pit is formed between the front transport block and the rear transport block, a cross section of the rear transport block gradually decreases from top to bottom, the rear transport block is provided with a corresponding first side wall and a second side wall, the first side wall is arranged between the front transport block and the second side wall, a first recessed portion is arranged in the middle of the first side wall, a first protrusion is arranged in the middle of the second side wall, the first protrusion and the first recessed portion are oriented in the same direction as the flow direction of the reaction gas, and the second side wall is perpendicular to the surface of the flow field body; The front transport block is provided with a corresponding third side wall and a fourth side wall, a second protrusion is provided in the middle of the third side wall, a second recess is provided in the middle of the fourth side wall, the second recess is provided between the second protrusion and the rear transport block, and the second protrusion and the second recess are both oriented in the opposite direction to the flow direction of the reaction gas; The plurality of transport blocks are arranged in two or more rows in the flow channel.
2. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to claim 1, Features: The third side wall and the fourth side wall are both perpendicular to the surface of the flow field body.
3. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to claim 1, Features: The second side wall, the third side wall and the fourth side wall are all arc surfaces, and the first side wall is a curved surface.
4. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to claim 1, Features: The areas of the upper end surface and the lower end surface of the front transport block are equal.
5. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to claim 1, Features: The flow field body and the transport block are made of stainless steel.
6. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to any one of claims 1 to 5, Features: The flow field itself is a parallel flow field.
7. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to any one of claims 1 to 5, Features: The flow field itself is a serpentine flow field.
8. A bionic self-transport drainage flow field of a proton exchange membrane fuel cell bipolar plate according to any one of claims 1 to 5, Features: The flow field itself is an interdigital flow field.