A proton exchange membrane fuel cell transport channel with multiple texture coupling and method of fabrication

Abstract

The application provides a proton exchange membrane fuel cell transport channel with multiple texture coupling and a processing method, the transport channel is a combination of a bipolar plate and a gas diffusion layer, the bipolar plate surface is provided with a plurality of spaced transport channels, and the gas diffusion layer surface is provided with a plurality of perforated structures; each perforated structure is located above the transport channel of the bipolar plate surface; the bipolar plate surface is provided with a coating, and the coating surface located in the transport channel has a micro-protrusion texture. The application processes the perforated structure on the gas diffusion layer, the perforated structure has a distribution of dense middle and sparse periphery, gas can quickly pass through the diffusion layer to react, and the generated water can also quickly flow into the transport channel through the perforated structure, meanwhile, the micro-protrusion texture in the transport channel can increase the surface hydrophobicity, and then the liquid water is quickly discharged.

Description

Technical Field

[0001] This invention relates to the field of fuel cells, and in particular to a proton exchange membrane fuel cell transport channel with multiple textured couplings and a processing method thereof. Background Technology

[0002] With the vigorous development of the automotive industry, energy has become an urgent problem to be solved. Hydrogen fuel cells have gradually emerged and been applied to the automotive industry. Fuel cells can directly convert the chemical energy stored in fuel and oxidant into electrical energy, and have the characteristics of high conversion efficiency, environmental friendliness and high reliability.

[0003] In a fuel cell, the bipolar plate, also known as the current collector, plays a crucial role in supporting the fuel cell, collecting current, providing channels for the coolant, and separating the oxidant and reductant. The gas diffusion layer plays a vital role in supporting the catalyst layer, collecting current, conducting gases, and removing water, a product of the reaction. During the process of generating electricity, the interface between the cathode gas diffusion layer and the bipolar plate is prone to "flooding," leading to blockage of the gas channels and affecting the internal reactions, thus impacting the lifespan of the plates. Therefore, hydrophobic treatment of the bipolar plate transport channels and promoting water passage through the gas diffusion layer are essential.

[0004] Existing technologies all consider the hydrophobicity of bipolar plates. Existing technologies disclose a hydrophobic fuel cell bipolar plate and method, proposing laser processing within the bipolar plate's transport channels to create rectangular micro-protrusions, thereby improving the hydrophobicity of the transport channels by modifying the structure. Existing technologies also disclose an anti-corrosion coating for fuel cell bipolar plates and its preparation method, proposing the preparation of an anti-corrosion coating that achieves both corrosion resistance and hydrophobicity through a novel coating. Furthermore, some patents mention structural improvements to the gas diffusion layer. Existing technologies disclose a novel gas diffusion layer with a hierarchical microgroove structure and its preparation method, proposing the fabrication of a gas diffusion layer with a hierarchical microgroove structure by creating regularly distributed ridges and grooves of several micrometers to hundreds of micrometers in size in a perforated surface layer. However, existing technologies only study the bipolar plate and the gas diffusion layer individually, without considering the combination of improving bipolar plate wettability and perforation in the gas diffusion layer to achieve better regulation of water and gas transport. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a proton exchange membrane fuel cell transport channel with multiple textured couplings and a processing method. By fabricating a perforated structure on the gas diffusion layer, with the perforations distributed in a denser center and sparser periphery, gas can rapidly pass through the diffusion layer for reaction, and the generated water can also be quickly discharged into the transport channel through the perforated structure, preventing water blockage in the gas diffusion layer. Secondly, pits are fabricated on the surface of the bipolar plate to increase the contact area between the coating and the substrate, thereby increasing the coating's adhesion. Finally, by fabricating a micro-protrusion texture within the transport channel after coating, the micro-protrusion texture increases surface hydrophobicity, thus allowing liquid water to drain rapidly. This invention is simple and has strong industrial adaptability.

[0006] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0007] A proton exchange membrane fuel cell transport channel with multiple texture couplings is disclosed. The transport channel is a combination of a bipolar plate and a gas diffusion layer. The surface of the bipolar plate is provided with a plurality of spaced transport channels, and the surface of the gas diffusion layer is provided with a plurality of perforated structures. Each perforated structure is located above a transport channel on the surface of the bipolar plate. The surface of the bipolar plate is provided with a coating, and the surface of the coating located in the transport channel has a micro-protrusion texture.

[0008] Furthermore, the surface of the gas diffusion layer is divided into a dense region a, a sub-dense region b, and a sparse region c according to the spacing between adjacent perforated structures. The dense region a is located at the center of the gas diffusion layer, the sparse region c is located at the periphery of the gas diffusion layer, and the sub-dense region b is located between the dense region a and the sparse region c. The spacing between adjacent perforated structures in the dense region a is smaller than the spacing between adjacent perforated structures in the sub-dense region b, and the spacing between adjacent perforated structures in the sub-dense region b is smaller than the spacing between adjacent perforated structures in the sparse region c.

[0009] Furthermore, the spacing between adjacent perforated structures in the dense region a is S1 = 10-200 μm; the spacing between adjacent perforated structures in the sub-dense region b is S2 = 200-400 μm; the spacing between adjacent perforated structures in the sparse region c is S3 = 400-550 μm; and the area of ​​some of the perforated structures accounts for 5%-40% of the total area of ​​the gas diffusion layer.

[0010] Furthermore, the diameter D of the perforated structure is 20-120 μm, and the depth H of the perforated structure is 180-300 μm.

[0011] Furthermore, the surface of the bipolar plate is provided with several pits to increase the adhesion performance of the coating.

[0012] Furthermore, the diameter of the pit D0 is 10-50 μm, the depth of the pit H0 is 50-200 μm, and the distance between adjacent pits S0 is 40-500 μm; the area of ​​several of the pits accounts for 40%-80% of the total surface area of ​​the bipolar plate.

[0013] Furthermore, the height Ha of the micro-protrusion texture is 25μm-75μm, the diameter Da of the micro-protrusion texture is 70-150μm, and the spacing Sa between adjacent micro-protrusion textures is 150-350μm.

[0014] A method for fabricating a transport channel in a proton exchange membrane fuel cell with multiple texture couplings includes the following steps:

[0015] Perforated structures are fabricated on the surface of the gas diffusion layer using lasers;

[0016] Pits are created on the surface of the bipolar plate using a laser, and a coating is then sprayed onto the surface of the bipolar plate.

[0017] Micro-protrusion textures are fabricated on the coating surface located within the transport channel using lasers.

[0018] Furthermore, the laser parameters are as follows: divergence angle less than 8 mrad, spot diameter not greater than 7 mm, wavelength 1064 nm, power 10–500 W, single pulse energy 1–200 mJ, pulse width 1–110 ps, ​​repetition frequency 0–100 kHz; and scanning speed 50–2000 mm / s.

[0019] Furthermore, the spraying process parameters are as follows: spraying distance is 90-120mm, working current is 500-650A, working voltage is 50-80V, Ar gas velocity is 30-60 liters / min, powder feeding amount is 38-47g / min, cooling gas pressure is 0.3-0.6MPa, and spray gun moving speed is 30-80mm / s.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The proton exchange membrane fuel cell transport channel and processing method with multiple texture couplings described in this invention, the perforated structure can promote the rapid passage of gas and water generated in the reaction through the gas diffusion layer, and prevent the accumulation of water in the gas diffusion layer from preventing the gas from entering the interior for reaction.

[0022] 2. The proton exchange membrane fuel cell transport channel and processing method with multiple texture coupling described in this invention have a perforated texture that is dense in the middle and sparse at the periphery, which is consistent with the characteristics of intense reaction in the internal central region and gentle reaction at the edge.

[0023] 3. The proton exchange membrane fuel cell transport channel and processing method with multiple texture coupling described in this invention can increase surface hydrophobicity through micro-protrusion texture, thereby enabling liquid water to leave the transport channel quickly.

[0024] 4. The proton exchange membrane fuel cell transport channel with multiple texture coupling and the processing method described in this invention, wherein a pit texture is processed on the surface of the bipolar plate, the presence of the pit can greatly increase the contact area between the coating and the substrate, improve the adhesion between the coating and the plate, and prevent the coating from falling off.

[0025] 5. The proton exchange membrane fuel cell transport channel and processing method with multiple texture coupling described in this invention, with the synergistic effect of pits, micro-protrusion texture and perforation triple texture, improves the hydrophobicity of the transport channel, the gas permeability of the diffusion layer and the water discharge, thus achieving better water and gas transport. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the transport channel of a proton exchange membrane fuel cell with multiple texture couplings as described in this invention.

[0028] Figure 2 This diagram shows the water vapor transport relationship between the gas diffusion layer and the bipolar plate.

[0029] Figure 3 This is a top view of the gas diffusion layer and a diagram showing the division of regions.

[0030] Figure 4 This is a top view of the coated bipolar plate described in this invention.

[0031] Figure 5 This is a cross-sectional view of the coated bipolar plate described in this invention.

[0032] Figure 6 This is a top view of the bipolar plate described in this invention.

[0033] Figure 7 This is a schematic diagram of the perforated structure of the present invention.

[0034] Figure 8 This is a schematic diagram of the micro-protrusion texture of the present invention.

[0035] Figure 9 This is a schematic diagram of the recess of the present invention.

[0036] In the picture:

[0037] 1-Bipolar plate; 2-Coating; 3-Micro-protrusion texture; 4-Gas diffusion layer; 5-Perforated structure; 6-Pit; 7-Transport channel; a-Dense region; b-Sub-dense region; c-Sparse region. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] like Figure 1 and Figure 2As shown, the proton exchange membrane fuel cell transport channel with multiple textured couplings of the present invention comprises a bipolar plate 1 and a gas diffusion layer 4. The surface of the bipolar plate 1 has several spaced transport channels 7, and the surface of the gas diffusion layer 4 has several perforated structures 5. Each perforated structure 5 is located above a transport channel 7 on the surface of the bipolar plate 1. The surface of the bipolar plate 1 is coated with a coating 2, and the surface of the coating 2 located within the transport channels 7 has micro-protrusion textures 3. The perforated structures 5 can promote the rapid passage of gas and water generated in the reaction through the gas diffusion layer, preventing the accumulation of water in the gas diffusion layer from preventing gas from entering the interior for reaction.

[0042] like Figure 3 As shown, the surface of the gas diffusion layer 4 is divided into a dense region a, a sub-dense region b, and a sparse region c according to the spacing between adjacent perforated structures 5. The dense region a is located at the center of the gas diffusion layer 4, the sparse region c is located around the gas diffusion layer 4, and the sub-dense region b is located between the dense region a and the sparse region c. The spacing between adjacent perforated structures 5 in the dense region a is smaller than the spacing between adjacent perforated structures 5 in the sub-dense region b, and the spacing between adjacent perforated structures 5 in the sub-dense region b is smaller than the spacing between adjacent perforated structures 5 in the sparse region c.

[0043] like Figure 3 and Figure 7 As shown, the spacing between adjacent perforated structures 5 in the dense region a is S1 = 10-200 μm; the spacing between adjacent perforated structures 5 in the sub-dense region b is S2 = 200-400 μm; and the spacing between adjacent perforated structures 5 in the sparse region c is S3 = 400-550 μm. The area of ​​several of the perforated structures 5 accounts for 5%-40% of the total area of ​​the gas diffusion layer 4. The diameter D of the perforated structure 5 is 20-120 μm, and the depth H of the perforated structure 5 is 180-300 μm.

[0044] like Figure 6 and Figure 9 As shown, the surface of the bipolar plate 1 is provided with a plurality of pits 6 to increase the adhesion of the coating. The pits 6 can increase the contact area between the coating and the substrate, thereby improving the bonding force. The diameter of the pit 6 is D0 = 10-50 μm, the depth of the pit 6 is H0 = 50-200 μm, and the distance between adjacent pits 6 is S0 = 40-500 μm; the area of ​​the plurality of pits 6 accounts for 40%-80% of the total surface area of ​​the bipolar plate 1. The coating is a zinc coating, which can increase the corrosion resistance of the bipolar plate 1 and the gas diffusion layer 4.

[0045] like Figure 4 , Figure 5 and Figure 8As shown, the height Ha of the micro-protrusion texture 3 is 25μm-75μm, the diameter Da of the micro-protrusion texture 3 is 70-150μm, and the spacing Sa between adjacent micro-protrusion textures 3 is 150-350μm. The micro-protrusion texture 3 allows more air to be trapped within the texture, significantly improving the surface wettability of the transport channel.

[0046] The fabrication method of the proton exchange membrane fuel cell transport channel with multiple texture couplings according to the present invention includes the following steps:

[0047] A perforated structure 5 is fabricated on the surface of the gas diffusion layer 4 using a laser. The specific parameters of the laser fabrication are as follows: divergence angle less than 8 mrad, spot diameter not greater than 7 mm, wavelength 1064 nm, power 100 W, single pulse energy 100 m J, pulse width 70 ps, ​​repetition frequency 50 kHz, and scanning speed 500 mm / s.

[0048] A recess 6 is machined on the surface of a bipolar plate 1 using a laser, and a coating 2 is then sprayed onto the surface of the bipolar plate 1. The laser processing parameters are: divergence angle less than 8 mrad, spot diameter not greater than 7 mm, wavelength 1064 nm, power 80 W, pulse width 60 ps, ​​repetition frequency 70 kHz, and scanning speed 400 mm / s. The specific parameters for the spraying are: spraying distance 100 mm, operating current 550 A, operating voltage 60 V, Ar gas velocity 40 L / min, powder feed rate 42 g / min, cooling gas pressure 0.5 MPa, and spray gun moving speed 50 mm / s.

[0049] Micro-protrusion texture 3 is processed on the surface of coating 2 located within transport channel 7 using a laser. The parameters of the laser processing are: divergence angle less than 8 mrad, spot diameter not greater than 7 mm, wavelength of 1064 nm, power of 40 W, single pulse energy of 40 m J, pulse width of 80 ps, ​​repetition frequency of 60 kHz; and scanning speed of 800 mm / s.

[0050] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0051] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A transport channel for a proton exchange membrane fuel cell with multiple textured couplings, wherein the transport channel is a combination of a bipolar plate (1) and a gas diffusion layer (4), and the surface of the bipolar plate (1) is provided with a plurality of spaced transport channels (7), characterized in that, The gas diffusion layer (4) has a plurality of perforated structures (5) on its surface; each of the perforated structures (5) is located above the transport channel (7) on the surface of the bipolar plate (1); the surface of the bipolar plate (1) is provided with a coating (2), and the surface of the coating (2) located in the transport channel (7) has a micro-protrusion texture (3). The surface of the gas diffusion layer (4) is divided into a dense region a, a sub-dense region b, and a sparse region c according to the spacing between adjacent perforated structures (5). The dense region a is located at the center of the gas diffusion layer (4), the sparse region c is located around the gas diffusion layer (4), and the sub-dense region b is located between the dense region a and the sparse region c. The spacing between adjacent perforated structures (5) in the dense region a is smaller than the spacing between adjacent perforated structures (5) in the sub-dense region b, and the spacing between adjacent perforated structures (5) in the sub-dense region b is smaller than the spacing between adjacent perforated structures (5) in the sparse region c.

2. The proton exchange membrane fuel cell transport channel with multiple textured couplings according to claim 1, characterized in that, The spacing between adjacent perforated structures (5) in the dense region a is S1 = 10-200 μm; the spacing between adjacent perforated structures (5) in the sub-dense region b is S2 = 200-400 μm. The spacing between adjacent perforated structures (5) located in sparse region c is S3 = 400-550 μm; the area of ​​some of the perforated structures (5) accounts for 5%-40% of the total area of ​​the gas diffusion layer (4).

3. The proton exchange membrane fuel cell transport channel with multiple textured couplings according to claim 1, characterized in that, The diameter D of the perforated structure (5) is 20-120 μm, and the depth H of the perforated structure (5) is 180-300 μm.

4. The proton exchange membrane fuel cell transport channel with multiple textured couplings according to claim 1, characterized in that, The surface of the bipolar plate (1) is provided with several pits (6) to increase the adhesion performance of the coating.

5. The proton exchange membrane fuel cell transport channel with multiple textured couplings according to claim 4, characterized in that, The diameter of the pit (6) is D0=10-50μm, the depth of the pit (6) is H0=50-200μm, and the distance between adjacent pits (6) is S0=40-500μm; the area of ​​several pits (6) accounts for 40%-80% of the total surface area of ​​the bipolar plate (1).

6. The proton exchange membrane fuel cell transport channel with multiple textured couplings according to claim 1, characterized in that, The height Ha of the micro-protrusion texture (3) is 25μm-75μm, the diameter Da of the micro-protrusion texture (3) is 70-150μm, and the distance Sa between adjacent micro-protrusion textures (3) is 150-350μm.

7. A method for fabricating a proton exchange membrane fuel cell transport channel with multiple textured couplings according to any one of claims 1-6, characterized in that, Includes the following steps: A perforated structure (5) is fabricated on the surface of the gas diffusion layer (4) using a laser. A pit (6) is processed on the surface of the bipolar plate (1) by laser, and a coating (2) is sprayed on the surface of the bipolar plate (1). Micro-protrusion texture (3) is fabricated on the surface of coating (2) located within transport channel (7) using a laser.

8. The method for fabricating the transport channel of a proton exchange membrane fuel cell with multiple textured couplings according to claim 7, characterized in that, The laser parameters are as follows: divergence angle less than 8 mrad, spot diameter not greater than 7 mm, wavelength 1064 nm, power 10–500 W, single pulse energy 1–200 mJ, pulse width 1–110 ps, ​​repetition frequency 0–100 kHz; scanning speed 50–2000 mm / s.

9. The method for fabricating the transport channel of a proton exchange membrane fuel cell with multiple textured couplings according to claim 7, characterized in that, The spraying process parameters are as follows: spraying distance is 90-120mm, working current is 500-650A, working voltage is 50-80V, Ar gas velocity is 30-60 liters / min, powder feeding amount is 38-47g / min, cooling gas pressure is 0.3-0.6MPa, and spray gun moving speed is 30-80mm / s.

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