Fuel cell bipolar plate with composite directional drainage and ice suppression microstructure

Abstract

The invention discloses a fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure. The fuel cell bipolar plate comprises a reaction surface and a cooling surface, the reaction surface is provided with a gas inlet, a gas reaction area, two gas transition areas and a gas outlet; the gas inlet is communicated with one gas transition area, and the gas outlet is communicated with the other gas transition area; a plurality of runner ribs are arranged on the gas reaction area at intervals, and gas runners are formed between the adjacent runner ribs; the two ends of the gas flow channel are respectively communicated with the two gas transition areas; a plurality of spindle ribs and a plurality of super-hydrophobic ice-inhibiting micro-synapses are fixed on the surface of the gas flow channel; the cooling surface is provided with a liquid inlet, a cooling area, two cooling liquid shunting areas and a liquid outlet; the liquid inlet is communicated with one cooling liquid distribution area, and the liquid outlet is communicated with the other cooling liquid distribution area; and two ends of the cooling area are respectively communicated with the cooling liquid shunting area.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells, and in particular relates to a fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure. Background Art

[0002] Proton Exchange Membrane Fuel Cell (PEMFC) is an energy conversion device that directly converts hydrogen and oxygen into electricity, water and heat through electrochemical reactions. It is widely used in automobiles, portable power supplies and fixed power systems due to its advantages of high energy conversion efficiency, low pollution and fast start-up. However, a large amount of water is generated during the operation of the fuel cell. If the generated water cannot be removed in time, it is easy to cause flooding in the flow field, affecting the gas mass transfer efficiency, reaction activity and overall performance of the battery. In addition, in a low temperature environment, the water generated by the reaction will freeze and adhere to the surface of the gas flow channel, thereby blocking the gas flow channel. At present, although common bipolar plate flow field structures such as parallel flow fields have a small flow resistance, when the gas flow rate is low, water is easy to gather at the edge of the flow channel, making it difficult to form an effective drainage path, and it is more likely to freeze in a low temperature environment, thereby reducing the stability and durability of the battery.

[0003] In order to solve the above problems, bionic design has been widely used in the optimization of bipolar plate structures in recent years. In particular, the super-hydrophobic structure imitating the surface of lotus leaves, through the special morphology design in the microflow field, uses the solid-liquid-gas three-phase interface effect to isolate the reaction generated water into water droplets, and reduces the heat transfer area, slows down the freezing rate, and allows the droplets to slide out. For example, patent CN109524684A proposes to form a multi-level ridge and microchannel structure on the main body of the bipolar plate, and to improve the drainage efficiency by forming a liquid water film on the bottom channel surface; CN115360375A proposes a bipolar plate with a lotus leaf papilla structure, by arranging lotus leaf-like papillae on the surface of the flow channel, so that the generated water cannot infiltrate the bottom of the flow channel, but is separated and slid out in the form of water droplets. However, these technical solutions still have the following shortcomings: First, the rectangular structure of the multi-level ridges easily leads to local aggregation of liquid water, which cannot effectively support the water droplets to form a thin film, and the drainage effect is limited; second, the proposed lotus leaf synapse structure is complex and difficult to process, which is not conducive to the mass production of bipolar plates and the high-power density application of fuel cells; finally, the proposed drainage method is ultimately just to use the microstructure to construct a super-hydrophobic surface, and does not play an active drainage role.

[0004] Therefore, in order to further improve the drainage and ice suppression performance of fuel cells, it is urgent to develop an efficient bipolar plate structure. Combining the bionic superhydrophobic properties with the optimized microflow field structure, through precise guidance and active ice suppression, the shortcomings of the existing design can be significantly improved. To this end, the present invention proposes a fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure, the fuel cell bipolar plate comprises a reaction surface and a cooling surface; the reaction surface is provided with an air inlet, a gas reaction zone, two gas transition zones and an air outlet; the gas transition zones are respectively arranged on both sides of the gas reaction zone; the air inlet is connected to one of the gas transition zones, and the air outlet is connected to the other gas transition zone; a plurality of flow channel ribs are arranged at intervals on the gas reaction zone, and a gas flow channel is formed between adjacent flow channel ribs; the two ends of the gas flow channel are respectively connected to the two gas transition zones; a plurality of spindle ribs and a plurality of super-hydrophobic ice suppression microsynapses are fixed on the surface of the gas flow channel, and a composite directional drainage and ice suppression microstructure is formed by the spindle ribs and the super-hydrophobic ice suppression microsynapses; the cooling surface is provided with a liquid inlet, a cooling zone, two coolant diversion zones and a liquid outlet; the coolant diversion zones are respectively arranged on both sides of the cooling zone; the liquid inlet is connected to one of the coolant diversion zones, and the liquid outlet is connected to the other coolant diversion zone; the two ends of the cooling zone are respectively connected to the coolant diversion zones.

[0008] Preferably, the spindle ribs are arranged in a uniform array on the surface of the gas flow channel, the spindle ribs are arranged at intervals in the radial direction, and the spindle ribs are arranged continuously in the axial direction; and the superhydrophobic ice-suppressing microsynapses are evenly distributed on the surface of the gas flow channel on the side of the spindle ribs.

[0009] Preferably, the length of the spindle rib is 100-500 μm; the taper of the spindle rib is 5-20°; the axial spacing of the spindle ribs is 0-30 μm; and the radial spacing of the spindle ribs is 100-200 μm.

[0010] Preferably, the height of the super-hydrophobic ice-suppressing micro-synapses is 30-80 μm; the column diameter of the super-hydrophobic ice-suppressing micro-synapses is 30-60 μm; and the spacing between the super-hydrophobic ice-suppressing micro-synapses is 20-50 μm.

[0011] Preferably, the flow channel ribs are parallel to each other, and the cross-sections of the flow channel ribs and the gas flow channel are both rectangular; the depth of the gas flow channel is 0.8-1 mm, and the width of the gas flow channel is 0.8-1.2 mm; the width of the flow channel ribs is 0.8-1 mm.

[0012] Preferably, the air inlet and the air outlet are respectively located at two ends of the bipolar plate of the fuel cell, and the air inlet and the air outlet are arranged in a central symmetrical manner; and a plurality of cylinders for dispersing the gas are arranged in an array on the gas transition zone.

[0013] Preferably, a plurality of cooling ribs are arranged at intervals on the cooling zone, and a liquid flow channel is formed between adjacent cooling ribs; both ends of the liquid flow channel are respectively connected to two cooling liquid diversion areas; the cooling ribs are parallel to each other, and the cross-sections of the cooling ribs and the liquid flow channel are both rectangular; the depth of the liquid flow channel is 0.8 to 1 mm, and the width of the liquid flow channel is 0.8 to 1.2 mm; the width of the cooling ribs is 0.8 to 1 mm.

[0014] Preferably, the liquid inlet and the liquid outlet are respectively located at two ends of the bipolar plate of the fuel cell, and the liquid inlet and the liquid outlet are arranged in a central symmetrical manner; and a plurality of guide plates for diverting the coolant are provided on the coolant diversion area.

[0015] Preferably, sealing rings are respectively provided on the air inlet, air outlet, liquid inlet and liquid outlet; the air inlet is connected to an external air inlet pipeline, and the air outlet is connected to an external air outlet pipeline; the liquid inlet is connected to an external liquid inlet pipeline, and the liquid outlet is connected to an external liquid outlet pipeline.

[0016] Preferably, bolt holes are respectively provided at both ends of the fuel cell bipolar plate.

[0017] After adopting the above technical solution, the present invention has the following beneficial effects:

[0018] 1. The present invention sets a composite directional drainage and ice suppression microstructure composed of spindle ribs and super-hydrophobic ice suppression microsynapses in the gas reaction zone flow field, so that the water generated by the reaction no longer adheres to the surface of the gas flow channel and accumulates and freezes in the battery, but is repelled by the super-hydrophobic ice suppression microsynapse structure and gathers on the spindle rib surface. Under the action of Laplace pressure difference and surface free energy gradient, the water droplets on the surface of the spindle rib structure move from the low taper of the spindle rib to the high taper area, and the continuous spindle rib structure forms a directional drainage phenomenon. Thereby reducing the accumulation and freezing of water inside the battery, alleviating the phenomenon of water flooding and low-temperature freezing, and improving battery performance

[0019] 2. The super-hydrophobic ice-suppressing micro-synaptic structure of the present invention is much smaller than the diameter of the water droplets, and a solid-gas-liquid three-phase interface is formed between the micro-synaptic and the droplets. The air layer between the super-hydrophobic ice-suppressing micro-synaptic structure prevents the water in the gas flow channel from contacting the bottom wall of the flow channel through the micro-synaptic structure, and greatly reduces the path of heat conduction, effectively inhibiting ice formation, so that the droplets can only gather on the spindle rib part. The spindle ribs are arranged in a uniform array on the surface of the gas flow channel, arranged at intervals in the radial direction, and arranged continuously in the axial direction. Since the spindle rib structure has a certain taper, when the water droplets gather on the spindle rib surface, the contact angle at the spindle angle is larger, the axial roughness is smaller, and the surface energy is smaller, while the contact angle at the spindle node is smaller, the axial roughness is larger, and the surface energy is larger, thereby driving the water droplets to move toward the spindle node; in addition, since the droplets generate a Laplace pressure difference on the surface of the conical spindle rib, the droplets will also be prompted to move spontaneously toward the spindle node, and the continuous spindle rib structure constitutes a directional drainage phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of the reaction surface of the bipolar plate of the fuel cell of the present invention;

[0021] Figure 2 It is a schematic diagram of the partial three-dimensional structure of the gas reaction zone of the present invention;

[0022] Figure 3 It is a schematic diagram of the local three-dimensional structure of the spindle ribs and superhydrophobic ice-suppressing microsynapses of the present invention;

[0023] Figure 4 It is a schematic diagram of the three-dimensional structure of the cooling surface of the bipolar plate of the fuel cell of the present invention;

[0024] Figure 5 It is a schematic diagram of the partial three-dimensional structure of the cooling zone of the present invention.

[0025] The reference numerals in the figure are as follows:

[0026] 1. Reaction surface; 10. Air inlet; 11. Gas reaction zone; 110. Flow channel ribs; 111. Gas flow channel; 112. Spindle ribs; 113. Superhydrophobic ice-suppressing microsynapses; 12. Gas transition zone; 120. Cylinder; 13. Air outlet; 2. Cooling surface; 20. Liquid inlet; 21. Cooling zone; 210. Cooling ribs; 211. Liquid flow channel; 22. Coolant diversion zone; 220. Guide plate; 23. Liquid outlet; 3. Sealing ring; 4. Bolt hole. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] like Figures 1 to 5 As shown, a fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure, the fuel cell bipolar plate includes a reaction surface 1 and a cooling surface 2. In this embodiment, the front side of the fuel cell bipolar plate is the reaction surface 1, and the back side of the fuel cell bipolar plate is the cooling surface 2; the reaction surface 1 is provided with an air inlet 10, a gas reaction zone 11, two gas transition zones 12 and an air outlet 13; the gas transition zones 12 are respectively provided on both sides of the gas reaction zone 11; the air inlet 10 is connected to one of the gas transition zones 12, and the air outlet 13 is connected to the other gas transition zone 12; a plurality of flow channel ribs 110 are arranged at intervals on the gas reaction zone 11, and a gas flow channel is formed between adjacent flow channel ribs 110 111; the two ends of the gas flow channel 111 are respectively connected to the two gas transition zones 12; a plurality of spindle ribs 112 and a plurality of super-hydrophobic ice-suppressing micro-synapses 113 are fixed on the surface of the gas flow channel 111, and a composite directional drainage and ice-suppressing micro-structure is formed by the spindle ribs 112 and the super-hydrophobic ice-suppressing micro-synapses 113; the cooling surface 2 is provided with a liquid inlet 20, a cooling zone 21, two coolant diversion zones 22 and a liquid outlet 23; the coolant diversion zones 22 are respectively arranged on both sides of the cooling zone 21; the liquid inlet 20 is connected to one of the coolant diversion zones 22, and the liquid outlet 23 is connected to the other coolant diversion zone 22; the two ends of the cooling zone 21 are respectively connected to the coolant diversion zones 22.

[0029] like Figures 1 to 5 As shown, the spindle ribs 112 are arranged in a uniform array on the surface of the gas flow channel 111 , the spindle ribs 112 are arranged at intervals in the radial direction, and the spindle ribs 112 are arranged continuously in the axial direction; the superhydrophobic ice-suppressing microsynapses 113 are evenly distributed on the surface of the gas flow channel 111 on the side of the spindle ribs 112 .

[0030] like Figures 1 to 5 As shown, the length of the spindle rib 112 is 100-500 μm; the taper of the spindle rib 112 is 5-20°; the axial spacing of the spindle ribs 112 is 0-30 μm; and the radial spacing of the spindle ribs 112 is 100-200 μm.

[0031] like Figures 1 to 5 As shown, the height of the super-hydrophobic ice-suppressing micro-synapses 113 is 30-80 μm; the column diameter of the super-hydrophobic ice-suppressing micro-synapses 113 is 30-60 μm; and the spacing between the super-hydrophobic ice-suppressing micro-synapses 113 is 20-50 μm.

[0032] like Figures 1 to 5 As shown, the flow channel ribs 110 are parallel to each other, and the cross-sections of the flow channel ribs 110 and the gas flow channel 111 are both rectangular; the depth of the gas flow channel 111 is 0.8-1 mm, and the width of the gas flow channel 111 is 0.8-1.2 mm; the width of the flow channel ribs 110 is 0.8-1 mm.

[0033] like Figures 1 to 5 As shown, the air inlet 10 and the air outlet 13 are respectively located at two ends of the bipolar plate of the fuel cell, and the air inlet 10 and the air outlet 13 are arranged in a central symmetrical manner; a plurality of cylinders 120 for dispersing the gas are arranged in an array on the gas transition zone 12 .

[0034] like Figures 1 to 5 As shown, a plurality of cooling ribs 210 are arranged at intervals on the cooling zone 21, and a liquid flow channel 211 is formed between adjacent cooling ribs 210; both ends of the liquid flow channel 211 are respectively connected to two coolant diversion zones 22; the cooling ribs 210 are parallel to each other, and the cross-sections of the cooling ribs 210 and the liquid flow channel 211 are both rectangular; the depth of the liquid flow channel 211 is 0.8 to 1 mm, and the width of the liquid flow channel 211 is 0.8 to 1.2 mm; the width of the cooling ribs 210 is 0.8 to 1 mm.

[0035] like Figures 1 to 5 As shown, the liquid inlet 20 and the liquid outlet 23 are respectively located at the two ends of the fuel cell bipolar plate, and the liquid inlet 20 and the liquid outlet 23 are arranged in a central symmetrical manner; a plurality of guide plates 220 for diverting the coolant are arranged on the coolant diversion area 22.

[0036] like Figures 1 to 5 As shown, sealing rings 3 are respectively provided on the air inlet 10, the air outlet 13, the liquid inlet 20 and the liquid outlet 23; the air inlet 10 is connected to the external air inlet pipeline, and the air outlet 13 is connected to the external air outlet pipeline; the liquid inlet 20 is connected to the external liquid inlet pipeline, and the liquid outlet 23 is connected to the external liquid outlet pipeline.

[0037] like Figures 1 to 5 As shown, bolt holes 4 are respectively provided at both ends of the fuel cell bipolar plate.

[0038] The directional drainage and ice suppression principle of the fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure of the present invention is:

[0039] (1) The reaction gas reacts in the fuel cell to generate water, which diffuses into the gas flow channel 111;

[0040] (2) The condensed small water droplets are at the solid-gas-liquid three-phase interface formed by the super-hydrophobic ice-suppressing micro-synapses 113 at the bottom of the gas flow channel 111, and the air is trapped in the microstructure, which reduces the contact area between the droplets and the solid surface, thereby achieving super-hydrophobicity on the surface of the gas flow channel 111. In addition, the gas layer of the composite directional drainage ice-suppressing microstructure has a low thermal conductivity, which limits the transfer of heat and slows down the cooling rate, thereby inhibiting ice formation;

[0041] (3) The generated water is repelled by the superhydrophobic ice-suppressing microsynapses 113 on the surface of the gas flow channel 111 and aggregates toward the spindle ribs 112;

[0042] (4) Under the action of Laplace pressure difference and surface free energy gradient, the water droplets gathered on the surface of the spindle rib 112 move from the low taper area of ​​the spindle rib to the high taper area, and the continuous spindle ribs 112 constitute a directional drainage phenomenon; wherein, the calculation formula of the Laplace pressure difference is:

[0043]

[0044] Wherein: ΔP is the Laplace pressure difference; R1 and R2 are the local radii of the two ends of the droplet on the spindle rib 112, R1 is the small radius, and R2 is the large radius; γ is the water surface tension; α is the semi-cone angle; R0 is the droplet radius; R is the local radius of the spindle rib 112.

[0045] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure, characterized in that: The fuel cell bipolar plate comprises a reaction surface (1) and a cooling surface (2); the reaction surface (1) is provided with an air inlet (10), a gas reaction zone (11), two gas transition zones (12) and an air outlet (13); the gas transition zones (12) are respectively provided on both sides of the gas reaction zone (11); the air inlet (10) is connected to one of the gas transition zones (12), and the air outlet (13) is connected to the other gas transition zone (12); a plurality of flow channel ribs (110) are arranged at intervals on the gas reaction zone (11), and a gas flow channel (111) is formed between adjacent flow channel ribs (110); the two ends of the gas flow channel (111) are respectively connected to the two gas transition zones (12); A plurality of spindle ribs (112) and a plurality of super-hydrophobic ice-suppressing micro-synapses (113) are fixed on the surface of the gas flow channel (111), and a composite directional drainage ice-suppressing micro-structure is formed by the spindle ribs (112) and the super-hydrophobic ice-suppressing micro-synapses (113); a liquid inlet (20), a cooling zone (21), two cooling liquid diversion zones (22) and a liquid outlet (23) are provided on the cooling surface (2); the cooling liquid diversion zones (22) are respectively provided on both sides of the cooling zone (21); the liquid inlet (20) is connected to one of the cooling liquid diversion zones (22), and the liquid outlet (23) is connected to the other cooling liquid diversion zone (22); and both ends of the cooling zone (21) are respectively connected to the cooling liquid diversion zones (22).

2. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: The spindle ribs (112) are arranged in a uniform array on the surface of the gas flow channel (111), the spindle ribs (112) are arranged at intervals in the radial direction, and the spindle ribs (112) are arranged continuously in the axial direction; and the superhydrophobic ice-suppressing microsynapses (113) are uniformly distributed on the surface of the gas flow channel (111) on the side of the spindle ribs (112).

3. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: The length of the spindle rib (112) is 100 to 500 μm; the taper of the spindle rib (112) is 5 to 20°; the axial spacing of the spindle ribs (112) is 0 to 30 μm; and the radial spacing of the spindle ribs (112) is 100 to 200 μm.

4. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: The height of the super-hydrophobic ice-suppressing micro-synapses (113) is 30 to 80 μm; the column diameter of the super-hydrophobic ice-suppressing micro-synapses (113) is 30 to 60 μm; and the spacing between the super-hydrophobic ice-suppressing micro-synapses (113) is 20 to 50 μm.

5. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: The flow channel ribs (110) are parallel to each other, and the cross-sections of the flow channel ribs (110) and the gas flow channel (111) are both rectangular; the depth of the gas flow channel (111) is 0.8 to 1 mm, and the width of the gas flow channel (111) is 0.8 to 1.2 mm; the width of the flow channel ribs (110) is 0.8 to 1 mm.

6. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: The air inlet (10) and the air outlet (13) are respectively located at two ends of the bipolar plate of the fuel cell, and the air inlet (10) and the air outlet (13) are arranged in a centrally symmetrical manner; a plurality of cylinders (120) for dispersing gas are arranged in an array on the gas transition zone (12).

7. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: A plurality of cooling ribs (210) are arranged at intervals on the cooling zone (21), and a liquid flow channel (211) is formed between adjacent cooling ribs (210); two ends of the liquid flow channel (211) are respectively connected to two cooling liquid diversion zones (22); the cooling ribs (210) are parallel to each other, and the cross-sections of the cooling ribs (210) and the liquid flow channel (211) are both rectangular; the depth of the liquid flow channel (211) is 0.8 to 1 mm, and the width of the liquid flow channel (211) is 0.8 to 1.2 mm; the width of the cooling ribs (210) is 0.8 to 1 mm.

8. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: The liquid inlet (20) and the liquid outlet (23) are respectively located at two ends of the fuel cell bipolar plate, and the liquid inlet (20) and the liquid outlet (23) are arranged in a central symmetric manner; and a plurality of guide plates (220) for diverting the coolant are arranged on the coolant diversion area (22).

9. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure as claimed in claim 1, characterized in that: The air inlet (10), the air outlet (13), the liquid inlet (20) and the liquid outlet (23) are respectively provided with sealing rings (3); the air inlet (10) is connected to an external air inlet pipeline, and the air outlet (13) is connected to an external air outlet pipeline; the liquid inlet (20) is connected to an external liquid inlet pipeline, and the liquid outlet (23) is connected to an external liquid outlet pipeline.

10. A fuel cell bipolar plate with a composite directional drainage and ice suppression microstructure according to claim 1, characterized in that: Bolt holes (4) are respectively arranged at both ends of the fuel cell bipolar plate.

Images