A flow field plate for a fuel cell, its preparation method, and a bipolar plate for a fuel cell.

Abstract

This invention discloses a fuel cell flow field plate, its preparation method, and a fuel cell bipolar plate. The fuel cell flow field plate includes a columnar ridge flow channel plate, which has a flow field region. Within the flow field region, there are several columnar ridge arrays, forming at least one main flow channel between the columnar ridge arrays. Each columnar ridge array is composed of several spaced-apart columnar ridges, with microchannels formed between adjacent columnar ridges. The width of the main flow channel is greater than the width of the microchannels and is connected to them. This invention improves the uniformity of the reaction medium distribution, reduces the pressure drop within the flow field region, and mitigates the "flooding" problem, effectively enhancing the output performance and operational stability of the fuel cell.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell flow field plate, its preparation method, and a fuel cell bipolar plate. Background Technology

[0002] Fuel cells, due to their high energy conversion efficiency, environmental friendliness, low noise, flexibility, reliability, and continuous power supply, have demonstrated enormous development potential and broad application prospects in the energy field. In proton exchange membrane fuel cells (PEMFCs), the flow field plate is an indispensable core component. Its main function is to guide the flow direction of the reaction medium (reactant gas), ensuring its uniform distribution throughout the membrane electrode assembly (MEA) and allowing it to reach the catalyst layer through the diffusion layer to participate in the electrochemical reaction. Simultaneously, it is responsible for expelling the water generated during the electrochemical reaction from the cell. The design of the flow field plate is crucial for improving the utilization efficiency of the fuel cell's reactant gas, drainage, and heat dissipation performance.

[0003] Traditional flow field plate designs typically employ a serpentine flow channel structure. This design increases the reaction area and extends the contact path between the reaction medium and the membrane electrode, thus improving reaction efficiency to some extent. However, this design has some inherent drawbacks in practical applications: First, at the turning points of the serpentine flow channel, the flow rate of the reaction medium decreases significantly, which can easily lead to the accumulation of liquid water generated by the electrochemical reaction in this area, forming a local "flooding" phenomenon. This "flooding" phenomenon not only hinders the effective diffusion and mass transfer of the reaction medium, but may also exacerbate the difficulty of drainage, resulting in some electrode reaction areas not receiving sufficient reaction medium, thereby causing a decline in battery performance.

[0004] Second, when the reaction medium flows in the serpentine channel, it must overcome multiple sharp turns (channel turning points) and channel friction, resulting in pressure drop and increased energy loss, i.e., a large pressure drop inside the flow field. Especially at the channel turning points, if a large amount of liquid water accumulates, it will further increase the flow resistance, causing additional power consumption (parasitic pump power loss), ultimately reducing energy conversion efficiency and affecting the output power and net efficiency of the fuel cell.

[0005] Third, traditional fuel cells employ a structural design where the flow field plate and the conductive plate (or current collector) are separate components. These are independent parts, stacked and bonded together along the thickness of the fuel cell. The flow field plate, located between the conductive plate and the membrane electrode assembly, only serves the functions of guiding the reaction medium and managing water, while the conductive plate only serves the functions of electron conduction and structural support. This separate design increases the number of fuel cell components, resulting in a larger overall size and weight, and lower structural compactness and integration. Furthermore, the increased number of contact interfaces between components introduces additional contact resistance, which is detrimental to improving the conductivity and long-term operational stability of the fuel cell.

[0006] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of uneven distribution of reaction medium, large pressure drop inside the flow field region, and easy accumulation of liquid water in the existing fuel cell flow field plate structure, which affect the mass transfer efficiency of the reaction medium.

[0008] To achieve the above objectives, the present invention provides a fuel cell flow field plate, including a columnar ridge flow channel plate. The columnar ridge flow channel plate has a flow field region, and the flow field region is provided with a plurality of columnar ridge arrays. The gaps between the columnar ridge arrays and the bottom surface of the flow field region together form at least one main flow channel. The columnar ridge array is composed of a plurality of spaced columnar ridges, and the gaps between adjacent columnar ridges and the bottom surface of the flow field region together form microflow channels. The width of the main flow channel is greater than the width of the microflow channel and is connected to the microflow channel.

[0009] Optionally, the two opposite ends of the columnar ridge channel plate are respectively provided with a reaction medium inlet and a reaction medium outlet, and the columnar ridge array includes: The central main array extends along the axial direction from the inlet to the outlet of the reaction medium, penetrating the middle of the flow field region; At least two side arrays are symmetrically distributed on both sides of the central main array; the gap between the central main array and the side arrays together with the bottom surface of the flow field region forms the main channel.

[0010] Optionally, the columnar ridge array comprises four lateral sub-arrays symmetrically distributed on both sides of the central main array, with an upper sub-array and a lower sub-array on each side of the central main array; the main channel includes: The longitudinal main channel is located between the central main array and each side partial array, and is used to divert the reaction medium from the reaction medium inlet to each side partial array. The transverse main channel, located between the upper and lower sub-arrays on the same side, is connected to the longitudinal main channel and is used to guide the reaction medium to flow from the upper sub-array to the lower sub-array.

[0011] Optionally, the columnar ridges in the central main array and each side partial array are arranged in a uniform row-column aligned manner.

[0012] Optionally, the width of the microchannel is 100μm to 500μm.

[0013] Optionally, the columnar ridge flow channel plate is constructed using a projection micro-stereolithography 3D printing process. Optionally, the columnar ridge channel plate is a circular plate.

[0014] Optionally, the surface of the fuel cell flow field plate is provided with a metal electroplating layer.

[0015] Accordingly, the present invention also provides a method for preparing the above-mentioned fuel cell flow field plate, comprising: Step S1: Provide a base plate, wherein the base plate has a pre-formed cavity for forming a columnar ridge channel plate; Step S2: Using projection micro-stereolithography 3D printing technology, the columnar ridge flow channel plate is constructed in the molding cavity to form the flow field plate body; Step S3: Metal electroplating is performed on the surface of the flow field plate to form a metal electroplating layer.

[0016] Accordingly, the present invention also provides a fuel cell bipolar plate comprising the above-described fuel cell flow field plate.

[0017] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: This invention establishes an array of columnar ridges, consisting of multiple spaced columnar ridges, within the flow field region. Microchannels are formed between adjacent columnar ridges, and a main flow channel, wider than and connected to the microchannels, is configured. This significantly improves the uniformity of the reaction medium distribution, reduces the pressure drop within the flow field region, and avoids the "flooding" problem. Specifically: On the one hand, because the columnar ridges are arranged at intervals, the reaction medium is forcibly divided after impacting the columnar ridges, forming several fine streams. As these streams flow around the columnar ridges, they can undergo lateral diffusion and interweaving flow in the microchannels between adjacent columnar ridges. After flowing around the columnar ridges, they will converge downstream of the columnar ridges. Therefore, the columnar ridge array can split, turbulent, and remix the reaction medium, promoting the uniform diffusion of the reaction medium to the entire reaction area of ​​the membrane electrode, weakening the local gas shortage phenomenon, and allowing the electrochemical reaction to proceed uniformly and fully on the surface of the membrane electrode, thereby effectively improving the overall output performance and operational stability of the fuel cell.

[0018] On the other hand, the flow path of the reaction medium is decomposed into multiple relatively short parallel paths (microchannels) through the columnar ridge, which can significantly reduce the frictional resistance during the flow of the reaction medium, thereby effectively reducing the pressure drop inside the flow field region, reducing additional power consumption, and improving the operating efficiency of the fuel cell.

[0019] On the other hand, since the width of the microchannel is only 100μm~500μm (far smaller than the width of conventional serpentine channels), based on the principles of fluid mechanics, under the premise that the input flow rate of the reaction medium is basically the same as the overall flow area of ​​the flow field, the narrow size design of the microchannel will significantly increase the flow velocity of the reaction medium in the microchannel inside the columnar ridge array. The increased flow velocity can have a stronger carrying effect on liquid water, promote the accumulation of liquid water into the main channel, thereby quickly discharging the liquid water accumulated in the flow field area, reducing the accumulation of liquid water in the flow field area, and thus improving the water management performance of the fuel cell and improving the operational stability of the fuel cell.

[0020] Furthermore, the flow field plate of the present invention has excellent conductivity by setting a metal electroplating layer on its surface, thereby eliminating the need for separate conductive plates and flow field plates in traditional fuel cells, reducing the number of battery components, effectively reducing the overall volume and weight of the fuel cell, improving structural compactness and integration, and reducing the contact interface between components, which helps to reduce contact resistance and further improve the overall performance of the fuel cell (energy conversion efficiency, power density, durability, etc.). Attached Figure Description

[0021] Figure 1 This is a top front view of a flow field plate provided by the present invention.

[0022] Figure 2 This is a top view of the back of a flow field plate provided by the present invention.

[0023] Figure 3 The image shows a side view of a flow field plate provided by the present invention; wherein, a represents a schematic diagram of the overall structure of the flow field plate, and b represents an enlarged schematic diagram of the columnar ridge flow channel plate.

[0024] Figure 4 The image shows a top front view of a columnar ridge channel plate provided by the present invention; wherein the arrows represent the flow direction of the reaction medium.

[0025] Figure 5 This invention provides a schematic diagram of the columnar ridge array distribution and main channel distribution of a columnar ridge flow channel plate.

[0026] Figure 6The present invention provides an overall flow field velocity vector cloud map of the flow field region on the surface of a columnar ridge flow channel plate; wherein, the arrow represents the flow direction of the reaction medium; a represents the overall flow field distribution of the reaction medium in the columnar ridge flow channel plate; b represents a local magnified view of region A in Figure a; c represents a local magnified view of region B in Figure a.

[0027] Figure 7 A flowchart illustrating a method for preparing a fuel cell flow field plate provided by the present invention.

[0028] Explanation of reference numerals in the attached figures: Base plate 10, columnar ridge channel plate 20, electrode lug 30, fixing pin hole 40, reaction medium inlet 21, reaction medium outlet 22, columnar ridge array 23, columnar ridge 24, microchannel 25, main channel 26, central main array 231, side sub-array 232, upper sub-array 2321, lower sub-array 2322, longitudinal main channel 261, transverse main channel 262. Detailed Implementation

[0029] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the fuel cell flow field plate, its preparation method, and the fuel cell bipolar plate proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0030] As described in the background section, traditional serpentine flow channels suffer from uneven distribution of reactant gases, significant pressure drops within the flow field region, and the tendency for liquid water to accumulate locally. These problems lead to uneven distribution of current and power densities in different regions of the membrane electrode assembly (MEA), potentially causing localized flooding or gas shortages, accelerating battery performance degradation, and thus affecting the fuel cell's output performance and operational stability. Especially under high current density conditions, the inherently high pressure drop of traditional serpentine flow channels introduces significant parasitic pump power losses, reducing the net efficiency of the fuel cell system. Simultaneously, liquid water accumulation further increases the pressure drop within the flow field region and hinders the effective delivery of reactant gases to the catalyst layer in the MEA, negatively impacting the normal operation of the fuel cell.

[0031] To address this, the present invention proposes a fuel cell flow field plate, its preparation method, and a fuel cell bipolar plate. By setting several columnar ridge arrays within the flow field region, a large number of parallel microchannels can be formed through the arrayed columnar ridges. These microchannels enable multi-directional and multi-path transport of the reaction medium, which is beneficial for the uniform distribution of the reaction medium. Simultaneously, the columnar ridges decompose the flow path of the reaction medium into multiple short-distance parallel paths (microchannels), which is beneficial for enhancing mass transfer and reducing pressure drop. Furthermore, the microchannels increase the flow velocity of the reaction medium, which helps the reaction medium carry liquid water out of the flow field quickly, thus improving the "flooding" problem.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] This invention provides a fuel cell flow field plate, such as Figure 1 , Figure 2 and Figure 3 As shown in Figure a, the fuel cell flow field plate includes a base plate 10 and a columnar ridge flow channel plate 20. In this embodiment, from a structural layout perspective, the fuel cell flow field plate includes a base plate 10 located on the periphery and a columnar ridge flow channel plate 20 located in the center. The base plate 10 is a square plate, and the columnar ridge flow channel plate 20 is a circular plate. The base plate 10 surrounds the outer periphery of the columnar ridge flow channel plate 20, and the inner periphery of the base plate 10 is adapted to the outer periphery of the columnar ridge flow channel plate 20. In this embodiment, the base plate 10 and the columnar ridge flow channel plate 20 are integrally formed, creating a seamless overall structure. It should be understood that in other embodiments, the base plate 10 and the columnar ridge flow channel plate 20 can be designed into other shapes according to the overall layout of the fuel cell, and this invention does not limit this.

[0034] The columnar ridge flow channel plate 20 defines a flow field region (not shown in the figure) on the surface facing the membrane electrode assembly. The flow field region has a certain depth relative to one side surface of the base plate 10 (the surface facing the membrane electrode assembly). The surface of the columnar ridge flow channel plate 20 facing the membrane electrode assembly and the inner wall of the hollow portion of the base plate 10 together enclose and define a flow space for accommodating and guiding the reaction medium.

[0035] To introduce and discharge the reaction medium into and out of the flow field region on the surface of the columnar ridge flow channel plate 20, the columnar ridge flow channel plate 20 is provided with a reaction medium inlet 21 and a reaction medium outlet 22. The columnar ridge flow channel plate 20 has a first end and a second end opposite to each other along its length direction, the reaction medium inlet 21 is located at the first end, and the reaction medium outlet 22 is located at the second end. In this embodiment, the reaction medium inlet 21 and the reaction medium outlet 22 are arranged opposite each other circumferentially along the flow field region, so that the reaction medium can enter from the reaction medium inlet 21, be distributed and participate in the electrochemical reaction in the flow field region, and then be discharged from the reaction medium outlet 22, forming a complete flow path.

[0036] The flow field region is provided with a plurality of columnar ridge arrays 23. Each columnar ridge array 23 consists of a plurality of spaced columnar ridges 24. The columnar ridges 24 extend upwards from the bottom surface of the flow field region. The columnar ridges 24 can be cylindrical, square, or other regular or irregular cross-sectional shapes. In this embodiment, the columnar ridges 24 are cylindrical structures. See [reference needed]. Figure 3 b. The height of the columnar ridges 24 matches the depth of the flow field region, such that after the flow field plate and the membrane electrode assembly are assembled, the top surface of the columnar ridges 24 is in contact with the surface of the membrane electrode or has a small gap. The gap between adjacent columnar ridges 24 and the bottom surface of the flow field region together form a microchannel 25. In some embodiments, the width of the gap between adjacent columnar ridges 24 (i.e., the width of the microchannel 25) is 100 μm to 500 μm; the cross-sectional width of the columnar ridges 24 is 100 μm to 500 μm; and the height of the columnar ridges 24 is 0.2 mm to 0.8 mm. The columnar ridge array 23 and the microchannel 25 serve at least the following functions: (1) The microchannel 25 forms a large number of parallel splitting and remixing paths in the flow field region. After the reaction medium enters the columnar ridge array 23, it is forcibly divided into multiple thin streams by the columnar ridges 24, and splitting and remixing occur continuously during the flow around the columnar ridges 24. This strong disturbance effectively breaks the stable concentration boundary layer that is easily formed in traditional flow channels (e.g., serpentine flow channels), promotes the full exchange of reaction medium between different regions, and allows the reaction gas to diffuse in multiple directions and uniformly to cover the reaction surface of the entire membrane electrode assembly, thereby significantly reducing the risk of local gas shortage and improving the uniformity of gas distribution inside the flow field. At the same time, compared with the traditional large-size strip flow channel ridges, the lattice-type columnar ridges 24 in this invention have a smaller contact area with the membrane electrode assembly. Under the premise that the total area of ​​the membrane electrode assembly remains unchanged, the ridge shielding area is greatly reduced, effectively increasing the effective area of ​​the membrane electrode that the reaction medium can directly contact and participate in the reaction, and ultimately effectively improving the output performance of the fuel cell.

[0037] (2) Compared to traditional flow channels, the gaps (100μm~500μm wide) formed between the columnar ridges 24 are on the order of micrometers, which significantly reduces the cross-sectional area of ​​the reaction medium in the microchannel 25. According to the continuity equation in fluid mechanics, under the premise that the total flow rate of the reaction medium remains unchanged, the reduction of the cross-sectional area will inevitably lead to a significant increase in the local reaction medium velocity. The high velocity of the reaction medium generates stronger aerodynamic shear force on the liquid water droplets attached to the surface of the flow field area, which can effectively peel off and carry liquid water, allowing the liquid water to migrate quickly out of the flow field area with the reaction medium, avoiding the local retention and accumulation of liquid water in the flow field area, thereby improving the flooding phenomenon in the flow field area and enhancing the fuel cell's water management capability.

[0038] (3) Traditional serpentine flow channels form a single flow path, with a long flow path and multiple flow channel turning points. In contrast, in this invention, since the microchannels 25 form a large number of parallel paths, the reaction medium can pass through many short-distance microchannels 25 simultaneously. This multi-path parallel flow mode significantly shortens the actual flow path of the reaction medium, thereby reducing the frictional resistance within the flow field region and effectively suppressing the increase in the overall pressure drop of the flow field region.

[0039] To reduce the overall flow resistance of the reaction medium within the flow region and provide a rapid transport channel for the reaction medium and liquid water, at least one main channel 26 is formed between the gaps between the columnar ridge arrays 23 and the bottom surface of the flow field region. The width of the main channel 26 is greater than the width of the microchannels 25; in some embodiments, the width of the main channel is 1 mm to 5 mm. The main channel 26 is interconnected with each microchannel 25, allowing the reaction medium to freely exchange between the main channel 26 and the microchannels 25. When the reaction medium enters the flow field region from the reaction medium inlet 21, a portion directly enters the microchannels 25 of the columnar ridge array 23, while another portion can be rapidly transported along the main channel 26 to various depth positions within the flow field region, and then gradually diverted into the microchannels 25 of adjacent columnar ridge arrays 23.

[0040] In a preferred layout of this embodiment, to further optimize the uniformity of reaction medium distribution within the flow field region, the columnar ridge array 23 is divided into multiple functional blocks along the flow direction of the reaction medium. Specifically, as shown... Figure 4As shown, the columnar ridge array 23 includes a central main array 231 and four side sub-arrays 232. The central main array 231 extends along the axial direction from the reaction medium inlet 21 to the reaction medium outlet 22, forming a rectangular strip that runs through the middle of the flow field region. The four side sub-arrays 232 are symmetrically distributed on both sides of the central main array 231. On each side of the central main array 231, an upper sub-array 2321 and a lower sub-array 2322 are provided. The columnar ridges 24 in the central main array 231 and each side sub-array 232 are uniformly arranged in rows and columns.

[0041] In the preferred arrangement of the columnar ridge array 23 described above, see... Figure 5 The main flow channel 26 includes two longitudinal main flow channels 261 and two transverse main flow channels 262. The longitudinal main flow channels 261 are located between the central main array 231 and each side sub-array 232, and their extension direction is parallel to the axis from the reaction medium inlet 21 to the reaction medium outlet 22. When the reaction medium flows into the flow field region from the reaction medium inlet 21, due to the low flow resistance within the longitudinal main flow channels 261, the reaction medium can be rapidly guided along the longitudinal main flow channels 261 to each side sub-array 232, allowing further diffusion of the reaction medium in the lateral portion of the flow field region. The transverse main flow channels 262 are located between the upper sub-array 2321 and the lower sub-array 2322 on the same side and are interconnected with the longitudinal main flow channels 261. The lateral main channel 262 extends in a direction approximately perpendicular to the longitudinal main channel 261. Its function is to guide the reaction medium from the upper sub-array 2321 to the lower sub-array 2322, achieving uniform distribution of the reaction medium in the lateral portion of the flow field region. The longitudinal main channel 261 and the lateral main channel 262 constitute the main flow channels for the reaction medium, allowing it to be orderly distributed to each microchannel. Through the diversion and convergence effects of the microchannels, the uniformity of the reaction medium concentration throughout the flow field region is improved, thereby making the current density on the membrane electrode assembly more consistent and improving the power output stability and overall efficiency of the fuel cell.

[0042] Figure 6 Figure 'a' shows the overall flow field velocity vector cloud diagram of the flow field region, with the arrows in the figure reflecting the flow direction of the reaction medium. Figure 6 b is the inlet region of the reaction medium ( Figure 6 A magnified view of region A in a diagram shows the reaction medium being diverted at the inlet by the columnar ridges, resulting in a localized jet flow and intense mixing. Figure 6 c represents the columnar ridge array region ( Figure 6A magnified view of region B in a shows that as the reaction medium flows through the columnar ridge array, it is subjected to periodic flow separation, wake vortex and local disturbance, which continuously thins the near-wall boundary layer and significantly enhances the mass transfer and distribution uniformity of the reaction medium in the flow field region.

[0043] In this embodiment, the base plate 10 is a square plate with a side length of 8.8 cm and a thickness of 1 mm. A tab 30 extends from the outer periphery of the base plate 10. The tab 30 is 2 cm wide, 3 cm long, and has the same thickness as the base plate 10. The tab 30 is used for current extraction or connection to a current collector. The base plate 10 and the tab 30 are provided with several fixing pin holes 40 for assembly and positioning.

[0044] In this embodiment, the columnar ridge flow channel plate 20 is a circular plate with a diameter of 1 cm. The depth of the flow field region on the surface of the columnar ridge flow channel plate 20 relative to the surface of the bottom plate 10, i.e., the depth of the main flow channel 26 and the microflow channel 25, is 0.5 mm. On the bottom surface of the flow field region, a plurality of columnar ridge arrays 23 are arrayed. The columnar ridges 24 in the columnar ridge array 23 are cylindrical, with a diameter of 300 μm and a height of 0.5 mm, matching the depth of the main flow channel 26 and the microflow channel 25, so that the top of the columnar ridge 24 is basically flush with the surface of the bottom plate 10. The spacing between adjacent columnar ridges 24 is 300 μm. Through the above parameter design, while ensuring the flow capacity of the reaction medium, local mass transfer can be enhanced and the pressure drop inside the flow field region can be reduced, resulting in a more uniform distribution of the reaction medium within the flow field region.

[0045] It is understood that the specific dimensions of the base plate, tabs, main flow channels and microflow channels, columnar ridges, etc., mentioned above are only a preferred embodiment. In practical applications, those skilled in the art can make proportional or non-proportional adjustments to parameters such as the diameter, spacing, and height of the columnar ridges, the array arrangement, the number and width of the main flow channels, and the overall dimensions of the base plate, according to the requirements of the effective reaction area of ​​the fuel cell, the stacking method of the fuel cell stack, and the sealing structure.

[0046] In this embodiment, a metal electroplating layer (not shown) is provided on the surfaces of both the columnar ridge flow channel plate 20 and the base plate 10. The metal electroplating layer can be made of at least one of nickel, copper, silver, gold, titanium, or their alloys, and is uniformly deposited on the surfaces of the columnar ridge flow channel plate 20 and the base plate 10 through chemical plating or electroplating processes. The metal electroplating layer provides a highly conductive path, allowing electrons to be conducted from the reaction area to the external circuit with low resistance. It also protects the plate from corrosion by the acidic electrolyte environment, thereby extending the service life of the fuel cell flow field plate. Through the metal electroplating layer, the fuel cell flow field plate integrates conductivity while providing reaction medium distribution, eliminating the need for conductive plate assemblies in traditional fuel cells. This reduces the number of components, effectively reducing the size and weight of the fuel cell, and decreasing the number of contact interfaces, which helps reduce assembly complexity and contact resistance.

[0047] The present invention also provides a method for preparing the above-mentioned fuel cell flow field plate. For example... Figure 7 As shown, the preparation method specifically includes: Step S1: Provide a base plate, wherein the base plate has a pre-formed cavity for forming a columnar ridge channel plate.

[0048] In this embodiment, the base plate is made of photosensitive resin, specifically a photosensitive polymer that can be cured by ultraviolet light. It possesses excellent molding precision, mechanical strength, and chemical corrosion resistance, making it suitable for the working environment of fuel cell flow fields and meeting the curing requirements of projection micro-stereolithography 3D printing. The base plate is a square plate with a pre-formed cavity at its center for constructing a columnar ridge flow channel plate. The contour of this cavity matches the contour of the columnar ridge flow channel plate, providing molding space for the subsequent in-situ construction of the columnar ridge flow channel plate. The outer periphery of the base plate also integrally forms tabs and multiple fixing pin holes for assembly and positioning.

[0049] Step S2: Using projection micro-stereolithography 3D printing technology, the columnar ridge flow channel plate is constructed in the molding cavity to form the flow field plate body.

[0050] The Projection Micro Stereolithography (PμSL) 3D printing process is a high-precision photopolymerization additive manufacturing technology based on surface exposure. Its core principle is to use digital micromirrors or similar dynamic mask devices to project a pre-defined two-dimensional cross-sectional pattern onto the surface of a liquid photosensitive resin in a single pass using ultraviolet light, triggering a localized photopolymerization reaction in the resin to form a cured thin layer. Subsequently, the platform descends according to a set layer thickness, repeating the projection and curing process to stack layers one by one, creating a high-precision three-dimensional microstructure.

[0051] In this embodiment, the specific operation process of step S2 is as follows: the base plate provided in step S1 is placed horizontally on the molding platform of the projection micro-stereolithography 3D printing equipment; liquid photosensitive resin of the same material as the base plate is injected into the molding cavity of the base plate through the printing equipment, so that the liquid photosensitive resin uniformly fills the molding cavity in the center of the base plate and fully contacts the inner wall of the molding cavity; the preset columnar ridge flow channel plate three-dimensional model is imported into the printing equipment, and the equipment slices the model into layers to generate two-dimensional cross-sectional exposure patterns of each layer; then the equipment cures the photosensitive resin layer by layer according to the preset layer thickness in the surface exposure method, starting from the bottom of the molding cavity of the base plate, and sequentially cures to form the bottom surface of the flow field area of ​​the columnar ridge flow channel plate, the columnar ridge array, the reaction medium inlet, the reaction medium outlet and other structures, wherein the columnar ridges extend upward from the bottom surface of the flow field area, and their height matches the depth of the flow field area, ensuring that the top surface of the columnar ridges is flush with the main surface of the base plate and does not protrude beyond the surface of the base plate.

[0052] During the curing process, the liquid photosensitive resin and the inner wall of the base plate molding cavity undergo a photopolymerization reaction simultaneously, forming a seamless, integrated structure between the molded columnar ridge flow channel plate and the base plate substrate material, without any mechanical assembly interfaces. Because the base plate and the columnar ridge flow channel plate are made of the same photosensitive resin, and the columnar ridge flow channel plate is cured layer-by-layer in situ within the base plate molding cavity, they form a seamless, integrated structure without any assembly interfaces. This effectively avoids the contact resistance problem present in traditional separate structures, while ensuring the overall structural integrity and dimensional accuracy of the flow field plate. After molding, the flow field plate is removed from the equipment, and the surface is cleaned with anhydrous ethanol to remove any remaining uncured photosensitive resin, followed by UV post-curing.

[0053] Step S3: Metal electroplating is performed on the surface of the flow field plate to form a metal electroplating layer.

[0054] In this embodiment, the flow field plate, which has been cleaned and cured in step S2, is placed in an electroplating tank. The flow field plate is used as the cathode, and metals such as nickel, gold, or platinum are selected as the anode. An acidic electroplating solution is used for electroplating. By controlling the electroplating current, electroplating time, and electroplating temperature, metal ions are uniformly deposited on the surface of the flow field to form a metal electroplating layer of uniform thickness. This metal electroplating layer simultaneously covers the columnar ridge surface of the columnar ridge flow channel plate and the inner walls of the main flow channel and microflow channel, ensuring that electrons can be smoothly conducted.

[0055] After electroplating, the flow field plate is removed, cleaned, and dried to remove residual electroplating solution from the surface, thus completing the preparation of the fuel cell flow field plate.

[0056] In summary, this invention constructs a columnar ridge array composed of spaced columnar ridges, forming microchannels between adjacent columnar ridges, and configuring a main flow channel with a width greater than the microchannels and connected to them. This creates a multi-stage flow-guiding configuration within the flow field region, characterized by uniform distribution of microchannels and rapid transport in the main flow channel. The columnar ridge array significantly improves the uniformity of the reaction medium distribution on the membrane electrode surface through its diversion, turbulence, and remixing effects. The microchannels shorten the effective flow path, drastically reducing the internal pressure drop within the flow field. Simultaneously, the narrow-sized structure of the microchannels increases local flow velocity, enhancing the ability to carry and discharge liquid water, effectively mitigating the "flooding" problem. Furthermore, the integrated structural design, achieved by applying a metal electroplating layer to the surface of the flow field plate to realize conductivity, eliminates the need for traditional separate conductive plates and flow field plate assemblies, reducing contact interfaces and assembly layers. This, in turn, improves the structural compactness, energy conversion efficiency, and operational durability of the fuel cell while reducing volume and weight.

[0057] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and 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. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0059] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0061] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A fuel cell flow field plate, characterized in that, The system includes a columnar ridge flow channel plate, which has a flow field region. The flow field region has a plurality of columnar ridge arrays, and the gaps between the columnar ridge arrays and the bottom surface of the flow field region together form at least one main flow channel. The columnar ridge array is composed of a plurality of spaced columnar ridges, and the gaps between adjacent columnar ridges and the bottom surface of the flow field region together form microflow channels. The width of the main flow channel is greater than the width of the microflow channel and is connected to the microflow channel.

2. The fuel cell flow field plate as described in claim 1, characterized in that, The columnar ridge flow channel plate has a reaction medium inlet and a reaction medium outlet at its two opposite ends, and the columnar ridge array includes: The central main array extends along the axial direction from the inlet to the outlet of the reaction medium, penetrating the middle of the flow field region; At least two side arrays are symmetrically distributed on both sides of the central main array; the gap between the central main array and the side arrays together with the bottom surface of the flow field region forms the main channel.

3. The fuel cell flow field plate as described in claim 2, characterized in that, The columnar ridge array comprises four lateral sub-arrays symmetrically distributed on both sides of the central main array, with an upper sub-array and a lower sub-array on each side of the central main array; the main channel includes: The longitudinal main channel is located between the central main array and each side partial array, and is used to divert the reaction medium from the reaction medium inlet to each side partial array. The transverse main channel, located between the upper and lower sub-arrays on the same side, is connected to the longitudinal main channel and is used to guide the reaction medium to flow from the upper sub-array to the lower sub-array.

4. The fuel cell flow field plate as described in claim 2 or 3, characterized in that, The central main array and the various side partial arrays contain several columnar ridges that are evenly arranged in rows and columns.

5. The fuel cell flow field plate as described in claim 1, characterized in that, The width of the microchannel is 100μm~500μm.

6. The fuel cell flow field plate as described in claim 1, characterized in that, The columnar ridge flow channel plate is constructed using projection micro-stereolithography 3D printing technology.

7. The fuel cell flow field plate as described in claim 1, characterized in that, The columnar ridge channel plate is a circular plate.

8. The fuel cell flow field plate as described in claim 1, characterized in that, The surface of the fuel cell flow field plate is provided with a metal electroplating layer.

9. A method for preparing a fuel cell flow field plate as described in any one of claims 1 to 8, characterized in that, include: Step S1: Provide a base plate, wherein the base plate has a pre-formed cavity for forming a columnar ridge channel plate; Step S2: Using projection micro-stereolithography 3D printing technology, the columnar ridge flow channel plate is constructed in the molding cavity to form the flow field plate body; Step S3: Metal electroplating is performed on the surface of the flow field plate to form a metal electroplating layer.

10. A fuel cell bipolar plate, characterized in that, It includes a fuel cell flow field plate as described in any one of claims 1 to 8.

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