A honeycomb bionics-based proton exchange membrane electrolyzer bipolar plate runner design

Abstract

This invention relates to the field of proton exchange membrane electrolyzers, and discloses a bipolar plate flow channel design for a proton exchange membrane electrolyzer based on honeycomb biomimetic principles. The design includes: an electrolyte inlet, a gas-liquid mixture outlet, a honeycomb biomimetic flow field region, an inlet distribution region, and an outlet collection region. The electrolyte inlet supplies deionized water into the flow channel; the gas-liquid mixture outlet discharges a mixture of electrolyte, hydrogen, and oxygen; the honeycomb biomimetic flow field region is composed of several periodically and closely arranged regular hexagonal flow channel units, covering the effective reaction area on the anode side of the bipolar plate; the electrolyte inlet and the gas-liquid mixture outlet are connected through a connecting channel within the honeycomb biomimetic flow field region. The flow channels of this invention exhibit a more uniform velocity field distribution and a more reasonable pressure field distribution, verifying that they maintain excellent and stable hydrodynamic performance under different operating conditions.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane electrolyzers, and particularly to a bipolar plate flow channel design for a proton exchange membrane electrolyzer based on honeycomb biomimetic principles. Background Technology

[0002] Proton exchange membrane electrolyzers (PEMWEs) are considered an ideal hydrogen production technology coupled with renewable energy sources due to their advantages such as high current density, fast dynamic response, compact structure, and high purity of hydrogen products. However, their high capital costs and relatively high energy consumption hinder large-scale commercial application. In PEMWEs, the flow field design of the bipolar plates is one of the key factors affecting their performance, directly related to the distribution of reactants (water), the discharge of products (oxygen and hydrogen), and electrochemical efficiency.

[0003] Currently, common flow channel structures mainly include parallel channels, serpentine channels, interdigitated channels, and point channels. While parallel channels offer advantages such as low flow resistance and low pressure drop, their simple groove design makes it difficult to achieve uniform distribution of reactants in large reaction areas. They also tend to form slug flows internally, interrupting the continuous water supply and leading to uneven local reactions and degraded performance. Serpentine channels generate forced convection through a single, tortuous long path, effectively promoting bubble removal, but this also results in significant fluid pressure loss, increasing system pumping power consumption, and easily causing local accumulation of product gases under high-pressure conditions. Interdigitated channels force fluid through a gas diffusion layer, generating strong convection and excellent bubble desorption, but their extremely high flow resistance leads to huge pressure losses, making them unsuitable for commercial electrolyzers, especially in high-pressure operating scenarios. Point or mesh channels can provide uniform mechanical support for the membrane electrode, but their discrete...

[0004] The pit or network design makes the gas exhaust path tortuous, which can easily lead to gas stagnation and hinder the contact between reactants and catalyst surfaces.

[0005] Parallel flow channels, due to their low flow resistance and uniform pressure loss, are considered a promising direction for large-scale electrolyzers. However, the core challenge lies in achieving uniform distribution of reactants over a large area. Current research is using advanced numerical simulation methods to deeply analyze the complex gas-liquid two-phase flow, heat transfer, and mass transfer processes within these channels to optimize key parameters such as channel dimensions. However, experimental studies have revealed an inherent drawback: the slug-like flow that easily forms in parallel flow channels can severely disrupt the continuous water supply, leading to poor performance.

[0006] The serpentine flow channel is a simple and widely used design in the past. Its single path generates forced convection, effectively removing product bubbles. Recent experimental comparisons show that among various flow channels, the single serpentine flow channel performs best due to its ability to create a continuous annular flow supplying water. However, its main drawback is the high pressure drop caused by the long flow channel, which can exacerbate product accumulation under high-pressure conditions.

[0007] Interdigitated flow channels: Traditional interdigitated flow channels achieve strong convection and excellent bubble desorption by forcing fluid through a gas diffusion layer, but their extremely high pressure loss limits their applicability in high-pressure scenarios. The latest research breakthrough involves mimicking the vein system of plant leaves to design fractal or "vein"-like interdigitated flow fields. This biomimetic design, through multi-stage flow splitting, can achieve uniform distribution of reactants and balanced distribution of flow resistance under high pressure, thereby effectively alleviating gas blockage problems and improving mass transfer efficiency.

[0008] Point-like channels: Point-like channels replace continuous trenches with a series of discrete pits or interconnected mesh-like grooves. The greatest advantage of this structure is that it provides very uniform mechanical support for the membrane electrode, thereby reducing contact resistance and promoting uniform distribution of reactants on the electrode surface. Current research focuses on optimizing the geometry, distribution density, and channel depth of the pits or meshes to minimize flow resistance while ensuring good drainage and venting capabilities.

[0009] Therefore, there is an urgent need to design a bipolar plate flow channel design for proton exchange membrane electrolyzers based on honeycomb biomimetic principles to address the shortcomings of existing electrolyzer flow channels. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bipolar plate flow channel design for a proton exchange membrane electrolyzer based on honeycomb bionics.

[0011] This invention is achieved through the following technical solution:

[0012] A bipolar plate flow channel design for a proton exchange membrane electrolyzer based on honeycomb bionics is characterized by: an electrolyte inlet, a gas-liquid mixture outlet, a honeycomb bionic flow field region, an inlet distribution region, and an outlet collection region.

[0013] The electrolyte inlet is used to supply deionized water into the flow channel;

[0014] The gas-liquid mixture outlet is used to discharge a mixture of electrolyte, hydrogen, and oxygen.

[0015] The honeycomb biomimetic flow field region is composed of several regular hexagonal flow channel units arranged periodically and closely, covering the effective reaction area on the anode side of the bipolar plate;

[0016] The electrolyte inlet and the gas-liquid mixture outlet are connected through a connecting channel within the honeycomb biomimetic flow field region.

[0017] The inlet distribution area is connected between the electrolyte inlet and the honeycomb biomimetic flow field area, and is used to evenly distribute the electrolyte to the honeycomb network.

[0018] The outlet collection area is connected between the honeycomb biomimetic flow field area and the gas-liquid mixture outlet, and is used to uniformly collect and export the gas-liquid mixture.

[0019] Furthermore, as the electrolysis of water proceeds, the amount of oxygen produced increases, leading to a higher probability of bubble generation. Therefore, in the honeycomb biomimetic flow field region, the radius R of the inscribed circle of the regular hexagonal flow channel unit can gradually decrease from the electrolyte inlet region to the gas-liquid mixing outlet region, that is, the flow channel width gradually increases, in order to promote the escape of bubbles.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. Significantly improves the uniformity and stability of the gas-liquid two-phase flow within the flow channel. By employing a honeycomb biomimetic flow field region composed of periodically closely arranged regular hexagonal flow channel units, this structure forms a highly symmetrical and interconnected fluid network on a two-dimensional plane. This structure effectively guides the flow path of the electrolyte, enabling it to be uniformly distributed throughout the entire effective reaction area, while providing numerous escape channels for oxygen bubbles generated by the electrolysis reaction, each with different directions. Compared to traditional serpentine or parallel flow channels, this invention greatly improves the uniformity of reactant and product distribution across the flow channel cross-section and along the flow path, thereby ensuring the uniformity of the current density on the proton exchange membrane surface and improving the overall electrolysis efficiency.

[0022] 2. The pressure distribution within the flow channel is optimized, creating a beneficial inlet and outlet pressure difference. The multi-path, networked characteristics of the honeycomb flow channel unit increase the tortuosity and contact area of ​​the fluid flow. With reasonable structural parameter design, a smoother and more uniform pressure gradient can be formed within the flow field. This design avoids the problems of insufficient driving force and gas stagnation caused by overly uniform pressure distribution at low flow velocities, such as in parallel flow channels, and also overcomes the excessive and uneven pressure drop caused by long flow paths and many corners in serpentine and interdigitated flow channels. The moderate and uniform inlet and outlet pressure difference created by this invention provides a stable and efficient driving force for the forced convection of reactants and the directional discharge of product bubbles.

[0023] 3. Highly efficient promotion of generated gas discharge and effective suppression of gas stagnation. The honeycomb network structure provides the shortest and most dispersed escape path for the generated bubbles. The connectivity between the hexagonal units prevents bubbles from accumulating and growing within a single channel, allowing them to be quickly carried away by the mainstream liquid in the surrounding channels and converge at the outlet collection area. This mechanism significantly reduces the possibility of gas forming a "gas expansion layer" or "gas blockage" on the catalyst layer surface or within the channels, greatly reducing the gas's obstruction of reactant transfer to the catalyst layer, improving gas-liquid mass transfer efficiency, and thus helping to reduce the electrolyzer's operating overpotential and improve performance.

[0024] 4. As the water electrolysis reaction proceeds, the amount of oxygen generated gradually increases, leading to a gradual increase in the number of bubbles in the electrolyte and a higher probability of forming a gas expansion layer. Therefore, based on a uniformly arranged honeycomb biomimetic flow channel structure, this invention designs a honeycomb biomimetic flow channel region with a gradient of sizes, i.e., the flow channel width gradually increases from the electrolyte inlet area to the gas-liquid mixture outlet, to promote the escape of a larger number and volume of bubbles.

[0025] 5. Strong structural robustness, easy to process and scale up. The flow channel structure of this invention is based on a regular hexagonal periodic arrangement, with clear design parameters and strong geometric regularity. This design not only facilitates performance optimization through computer simulation, but also ensures high repeatability and consistency during mass production, which helps to guarantee product quality and reduce manufacturing costs, providing a feasible flow field solution for the commercial application of PEM electrolyzers.

[0026] In summary, this invention cleverly combines the advantages of parallel flow channels and serpentine / interdigital flow channels, while avoiding their respective significant drawbacks through biomimetic design. Experimental data show that, under different inlet flow velocities, the flow channel of this invention exhibits a more uniform velocity field distribution and a more reasonable pressure field distribution for various working media such as water and oxygen, verifying that it maintains excellent and stable fluid dynamic performance under different operating conditions. Attached Figure Description

[0027] Appendix Figure 1 This is a two-dimensional planar schematic diagram of a PEM bipolar plate flow channel based on honeycomb bionics.

[0028] Appendix Figure 2 This is a schematic diagram of the vertical direction of a PEM bipolar plate flow channel based on honeycomb bionics.

[0029] Appendix Figure 3 This is a schematic diagram of the velocity distribution of a PEM bipolar plate flow channel based on honeycomb bionics when the H2O inlet flow velocity is 5 cm / s.

[0030] Appendix Figure 4This is a schematic diagram of the velocity distribution of a PEM bipolar plate flow channel based on honeycomb bionics when the H2O inlet velocity is 10 cm / s.

[0031] Appendix Figure 5 This is a schematic diagram of the pressure distribution in a PEM bipolar plate flow channel based on honeycomb bionics when the H2O inlet flow velocity is 5 cm / s.

[0032] Appendix Figure 6 This is a schematic diagram of the pressure distribution in a PEM bipolar plate flow channel based on honeycomb bionics when the H2O inlet flow velocity is 10 cm / s.

[0033] Appendix Figure 7 This is a schematic diagram of the velocity distribution of a PEM bipolar plate flow channel based on honeycomb bionics when the O2 inlet velocity is 5 cm / s.

[0034] Appendix Figure 8 This is a schematic diagram of the velocity distribution of a PEM bipolar plate flow channel based on honeycomb bionics when the O2 inlet velocity is 10 cm / s.

[0035] Appendix Figure 9 This is a schematic diagram of the pressure distribution in a PEM bipolar plate flow channel based on honeycomb bionics when the O2 inlet velocity is 5 cm / s.

[0036] Appendix Figure 10 This is a schematic diagram of the pressure distribution in a PEM bipolar plate flow channel based on honeycomb bionics when the O2 inlet velocity is 10 cm / s. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figure 1-10 The present invention provides a technical solution:

[0039] A bipolar plate flow channel design for a proton exchange membrane electrolyzer based on honeycomb bionics is characterized by: an electrolyte inlet, a gas-liquid mixture outlet, a honeycomb bionic flow field region, an inlet distribution region, and an outlet collection region.

[0040] The electrolyte inlet is used to supply deionized water into the flow channel;

[0041] The gas-liquid mixture outlet is used to discharge a mixture of electrolyte, hydrogen, and oxygen.

[0042] The honeycomb biomimetic flow field region is composed of several regular hexagonal flow channel units arranged periodically and closely, covering the effective reaction area on the anode side of the bipolar plate;

[0043] The electrolyte inlet and the gas-liquid mixture outlet are connected through a connecting channel within the honeycomb biomimetic flow field region.

[0044] The inlet distribution area is connected between the electrolyte inlet and the honeycomb biomimetic flow field area, and is used to evenly distribute the electrolyte to the honeycomb network.

[0045] The outlet collection area is connected between the honeycomb biomimetic flow field area and the gas-liquid mixture outlet, and is used to uniformly collect and export the gas-liquid mixture.

[0046] Furthermore, as the electrolysis of water proceeds, the amount of oxygen produced increases, leading to a higher probability of bubble generation. Therefore, in the honeycomb biomimetic flow field region, the radius R of the inscribed circle of the regular hexagonal flow channel unit can gradually decrease from the electrolyte inlet region to the gas-liquid mixing outlet region, that is, the flow channel width gradually increases, in order to promote the escape of bubbles.

[0047] Example 1:

[0048] like Figure 1 As shown in Figure a, Example 1 illustrates a honeycomb-inspired flow field plan design. The length of the bipolar plate flow channel in the PEM electrolytic cell is 70 mm, and the width is 38 mm; the radius of the inscribed circle of the regular hexagon is 0.75 mm. The vertical distance D1 between all regular hexagonal flow channel elements is equal, which is 2.25 mm; the horizontal distance D2 between all regular hexagonal flow channel elements is equal, which is 3.9 mm.

[0049] like Figure 2 As shown in Example 1, a PEM electrolyzer with a flow channel thickness of 3 mm based on honeycomb bionics is demonstrated.

[0050] Appendix Figure 3 a and appendix Figure 4 Figure a shows the velocity distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb-inspired PEM bipolar plate flow channel structure exhibits high consistency, indicating a significant improvement in the uniformity of H2O liquid distribution.

[0051] Appendix Figure 5 a and appendix Figure 6Figure a shows the pressure distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map of the middle honeycomb-inspired flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb-inspired PEM bipolar plate flow channel is more uniform, and that the H2O flow within the honeycomb-inspired PEM bipolar plate flow channel is more stable.

[0052] Appendix Figure 7 a and appendix Figure 8 Figure a shows the velocity distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb-inspired PEM bipolar plate flow channel structure exhibits high consistency, indicating a significant improvement in the uniformity of O2 gas distribution.

[0053] Appendix Figure 9 a and appendix Figure 10 Figure a shows the pressure distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map in the middle honeycomb-inspired flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb-inspired PEM bipolar plate flow channel is more uniform, and that the O2 flow within the honeycomb-inspired PEM bipolar plate flow channel is more stable.

[0054] Appendix Table 1 shows the inlet and outlet pressure difference data of a PEM bipolar plate flow channel based on honeycomb bionics under different inscribed circle radii, different flow velocities, and different working fluids. When the H2O flow velocity is 5 cm / s, the inlet and outlet pressure difference in Example 1 is 36.15 Pa; when the H2O flow velocity is 10 cm / s, the inlet and outlet pressure difference in Example 1 is 91.84 Pa.

[0055] When the O2 flow rate is 5 cm / s, the inlet and outlet pressure difference in Example 1 is 0.4610 Pa; when the O2 flow rate is 10 cm / s, the inlet and outlet pressure difference in Example 1 is 0.9651 Pa.

[0056] Example 2:

[0057] like Figure 1 As shown in Figure b, this example illustrates a honeycomb-inspired biomimetic flow field planar design. The length of the bipolar plate flow channel in the PEM electrolytic cell is 70 mm, and the width is 38 mm; the radius of the inscribed circle of the regular hexagon is 1.0 mm. The vertical distance D1 between all regular hexagonal flow channel elements is equal, which is 3.2 mm; the horizontal distance D2 between all regular hexagonal flow channel elements is equal, which is 5.54 mm.

[0058] like Figure 2As shown in Example 2, a PEM electrolyzer with a flow channel thickness of 3 mm based on honeycomb bionics is demonstrated.

[0059] Appendix Figure 3 b and appendix Figure 4 Figures b show the velocity distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb-inspired PEM bipolar plate flow channel structure exhibits high consistency, indicating a significant improvement in the uniformity of H2O liquid distribution.

[0060] Appendix Figure 5 b and appendix Figure 6 Figures b show the pressure distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map in the middle honeycomb-inspired flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb-inspired PEM bipolar plate flow channel is more uniform, and that the H2O flow within the honeycomb-inspired PEM bipolar plate flow channel is more stable.

[0061] Appendix Figure 7 b and appendix Figure 8 b represents the velocity distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb-inspired PEM bipolar plate flow channel structure exhibits high consistency, indicating a significant improvement in the uniformity of O2 gas distribution.

[0062] Appendix Figure 9 b and appendix Figure 10 Figures b show the pressure distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map in the middle honeycomb-inspired flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb-inspired PEM bipolar plate flow channel is more uniform, and that the O2 flow within the honeycomb-inspired PEM bipolar plate flow channel is more stable.

[0063] Appendix Table 1 shows the inlet and outlet pressure difference data of a PEM bipolar plate flow channel based on honeycomb bionics under different inscribed circle radii, different flow velocities, and different working fluids. When the H2O flow velocity is 5 cm / s, the inlet and outlet pressure difference in Example 2 is 17.88 Pa; when the H2O flow velocity is 10 cm / s, the inlet and outlet pressure difference in Example 2 is 48.24 Pa.

[0064] When the O2 flow rate is 5 cm / s, the inlet and outlet pressure difference in Example 2 is 0.2004 Pa; when the O2 flow rate is 10 cm / s, the inlet and outlet pressure difference in Example 2 is 0.4256 Pa.

[0065] Example 3:

[0066] like Figure 1 As shown in Figure c, this example illustrates a honeycomb-inspired biomimetic flow field planar design. The length of the bipolar plate flow channel in the PEM electrolytic cell is 70 mm, and the width is 38 mm; the radius of the inscribed circle of the regular hexagon is 1.25 mm. The vertical distance D1 between all regular hexagonal flow channel elements is equal, which is 3.75 mm; the horizontal distance D2 between all regular hexagonal flow channel elements is equal, which is 6.5 mm.

[0067] like Figure 2 As shown in Example 3, a PEM electrolyzer with a flow channel thickness of 3 mm based on honeycomb bionics is demonstrated.

[0068] Appendix Figure 3 c and appendix Figure 4 c represents the velocity distribution of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb biomimetic PEM bipolar plate flow channel structure exhibits high consistency, indicating that the uniformity of H2O liquid distribution has been significantly improved.

[0069] Appendix Figure 5 c and appendix Figure 6 c represents the pressure distribution diagram of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map of the middle honeycomb biomimetic flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb biomimetic PEM bipolar plate flow channel is more uniform, and that the H2O flow within the honeycomb biomimetic PEM bipolar plate flow channel is more stable.

[0070] Appendix Figure 7 c and appendix Figure 8 c represents the velocity distribution of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb biomimetic PEM bipolar plate flow channel structure exhibits high consistency, indicating a significant improvement in the uniformity of O2 gas distribution.

[0071] Appendix Figure 9 c and appendix Figure 10c represents the pressure distribution diagram of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the O2 inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map of the middle honeycomb biomimetic flow field region is lighter in color and has better color consistency, indicating that the pressure within the PEM bipolar plate flow channel based on honeycomb biomimetic design is more uniform, and that the O2 flow within the PEM bipolar plate flow channel based on honeycomb biomimetic design is more stable.

[0072] Appendix Table 1 shows the inlet and outlet pressure difference data of a PEM bipolar plate flow channel based on honeycomb bionics under different inscribed circle radii, different flow velocities, and different working fluids.

[0073] When the H2O flow rate is 5 cm / s, the inlet and outlet pressure difference in Example 3 is 17.44 Pa; when the H2O flow rate is 10 cm / s, the inlet and outlet pressure difference in Example 3 is 47.05 Pa.

[0074] When the O2 flow rate is 5 cm / s, the inlet and outlet pressure difference in Example 3 is 0.1942 Pa; when the O2 flow rate is 10 cm / s, the inlet and outlet pressure difference in Example 3 is 0.4131 Pa.

[0075] Example 4:

[0076] like Figure 1 As shown in Figure d, this example illustrates a planar design of a gradient honeycomb biomimetic flow field region. Since the amount of oxygen generated as the water electrolysis reaction proceeds increases, leading to a higher probability of bubble formation, the inscribed radius R of the regular hexagonal flow channel unit in the honeycomb biomimetic flow field region can gradually decrease from the electrolyte inlet region to the gas-liquid mixing outlet region, i.e., the flow channel width gradually increases, to promote bubble escape.

[0077] Figure 1 In section d, the length of the bipolar plate flow channel in the PEM electrolyzer is 70 mm and the width is 38 mm. The radius of the inscribed circle of the regular hexagon decreases from 1.25 mm to 0.75 mm, meaning that the width of the flow channel gradually increases as the electrolyte flows. The vertical distance D1 between all regular hexagonal flow channel units is equal, which is 3.75 mm; the horizontal distance D2 between all regular hexagonal flow channel units is equal, which is 6.5 mm.

[0078] like Figure 2 As shown in Example 2, a PEM electrolyzer with a flow channel thickness of 3 mm based on honeycomb bionics is demonstrated.

[0079] Appendix Figure 3 d and appendix Figure 4Figure d shows the velocity distribution of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb biomimetic PEM bipolar plate flow channel structure exhibits high consistency, indicating that the uniformity of H2O liquid distribution has been significantly improved.

[0080] Appendix Figure 5 d and appendix Figure 6 Figure d shows the pressure distribution of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the H2O inlet flow velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map of the middle honeycomb biomimetic flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb biomimetic PEM bipolar plate flow channel is more uniform, and that the H2O flow within the honeycomb biomimetic PEM bipolar plate flow channel is more stable.

[0081] Appendix Figure 7 d and appendix Figure 8 Figure a shows the velocity distribution of a honeycomb-inspired PEM bipolar plate flow channel structure when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the honeycomb-inspired PEM bipolar plate flow channel structure exhibits high consistency, indicating a significant improvement in the uniformity of O2 gas distribution.

[0082] Appendix Figure 9 d and appendix Figure 10 Figure d shows the pressure distribution of a PEM bipolar plate flow channel structure based on honeycomb biomimetic design when the O2 inlet velocity is 5 cm / s and 10 cm / s, respectively. It can be seen that the pressure cloud map of the middle honeycomb biomimetic flow field region is lighter in color and has better color consistency, indicating that the pressure within the honeycomb biomimetic PEM bipolar plate flow channel is more uniform, and that the O2 flow within the honeycomb biomimetic PEM bipolar plate flow channel is more stable.

[0083] Appendix Table 1 shows the inlet and outlet pressure difference data of a PEM bipolar plate flow channel based on honeycomb bionics under different inscribed circle radii, different flow velocities, and different working fluids. When the H2O flow velocity is 5 cm / s, the inlet and outlet pressure difference in Example 4 is 11.47 Pa; when the H2O flow velocity is 10 cm / s, the inlet and outlet pressure difference in Example 4 is 31.90 Pa.

[0084] When the O2 flow rate is 5 cm / s, the inlet and outlet pressure difference in Example 4 is 0.1198 Pa; when the O2 flow rate is 10 cm / s, the inlet and outlet pressure difference in Example 4 is 0.2565 Pa.

[0085] The data shows that a PEM bipolar plate flow channel based on honeycomb bionics optimizes the pressure distribution within the flow channel, creating a beneficial inlet and outlet pressure difference. The multi-path and network characteristics of the honeycomb flow channel unit increase the tortuosity and contact area of ​​the fluid flow, and with reasonable structural parameter design, it can form a more gentle and balanced pressure gradient in the flow field.

[0086] This design avoids the problems of insufficient driving force and gas retention caused by overly uniform pressure distribution at low flow rates, such as in parallel flow channels. It also overcomes the excessive and uneven pressure drop caused by long flow paths and many bends in serpentine and interdigitated flow channels. The moderate and uniform inlet and outlet pressure difference created by this invention provides a stable and efficient driving force for the forced convection of reactants and the directional discharge of product bubbles.

[0087] Furthermore, as the water electrolysis reaction proceeds, the amount of oxygen produced increases, leading to a higher probability of bubble formation. Therefore, based on the homogeneous honeycomb biomimetic flow field region, this invention gradually decreases the inscribed circle radius R of the regular hexagonal flow channel unit from the electrolyte inlet region to the gas-liquid mixing outlet region, i.e., the flow channel width gradually increases, to promote bubble escape.

[0088] In summary, a PEM bipolar plate flow channel structure based on honeycomb bionics can significantly improve the uniformity and stability of the gas-liquid two-phase flow within the flow channel, while optimizing the pressure distribution within the flow channel and forming a beneficial inlet and outlet pressure difference. This avoids the problems of insufficient driving force and gas retention that may occur in parallel flow channels at low flow rates due to overly uniform pressure distribution.

[0089] Appendix Table 1 shows the inlet and outlet pressure difference data of a PEM bipolar plate flow channel based on honeycomb bionics under different inscribed circle radii, different flow velocities, and different working fluids.

[0090]

[0091] The motion of liquid water in the bipolar plate channel of the PEM electrolyzer is modeled using the principles of mass and momentum conservation, and the expression is:

[0092]

[0093]

[0094] in, Indicates the porosity of the medium; Represents the velocity vector; Indicates the saturation level of liquid water; Indicates density; Corresponding quality source item; Indicates pressure; It is dynamic viscosity; This represents the momentum source term.

[0095] In the anode of a PEM electrolyzer, liquid water flows through the flow zone and interacts with the catalyst layer, promoting the electrochemical reaction to produce oxygen. The capillary pressure controlling liquid water transport within the porous medium of the anode can be expressed by the following equation:

[0096]

[0097]

[0098]

[0099] in, This represents the surface tension at the gas-liquid interface; Indicates the contact angle of the material; This indicates the pressure of the gas phase in the anode; This represents the liquid phase pressure in the anode, which is determined by Darcy's law:

[0100]

[0101]

[0102]

[0103]

[0104] in, Represents the relative permeability of the gas phase; Indicates the velocity of the gas phase; This indicates the velocity of the liquid phase.

[0105] Based on the above parameters, the governing equation for the gas phase can be expressed as:

[0106]

[0107] Among them, capillary diffusion coefficient Defined by the following expression:

[0108]

[0109] The momentum conservation equation of the system is expressed as follows:

[0110]

[0111] The mass conservation in a PEM electrolyzer is governed by the following equation:

[0112]

[0113] in, Indicates the mass fraction of the gaseous components (denoted as H2O, H2, and O2); This represents the effective diffusion coefficient of the species; Indicates the flow rate of this species; This corresponds to the source term for that species. The effective diffusion coefficient, adjusted for the Brugman correlation coefficient, is expressed as:

[0114]

[0115]

[0116] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A bipolar plate flow channel design for a proton exchange membrane electrolyzer based on honeycomb biomimetic principles, characterized in that, include: Electrolyte inlet, used to supply electrolyte into the flow channel; The gas-liquid mixture outlet is used to discharge the mixture of electrolyte and reaction-generated gas. The honeycomb biomimetic flow field region, located in the effective reaction area on the anode side of the bipolar plate, is composed of several regularly hexagonal flow channel units arranged periodically and closely to form an interconnected fluid network; the electrolyte inlet and the gas-liquid mixture outlet are connected through the connecting channels within the honeycomb biomimetic flow field region.

2. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 1, characterized in that, The inscribed circle radius R of the regular hexagonal flow channel unit satisfies: 0.5 mm ≤ R ≤ 2.0 mm.

3. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 2, characterized in that, The depth H of the regular hexagonal flow channel unit satisfies: 2.5 mm ≤ H ≤ 3.5 mm.

4. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 2, characterized in that, The vertical distance D1 between the centers of adjacent regular hexagonal flow channel units satisfies: 2.5R ≤ D1 ≤ 3.5R.

5. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 2, characterized in that, The horizontal distance D2 between the centers of adjacent regular hexagonal flow channel units satisfies: 4.9R ≤ D2 ≤ 5.5R.

6. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 1, characterized in that, It also includes an inlet distribution area and an outlet collection area; the inlet distribution area is connected between the electrolyte inlet and the honeycomb biomimetic flow field area, and is used to uniformly distribute the electrolyte to the honeycomb biomimetic flow field area; the outlet collection area is connected between the honeycomb biomimetic flow field area and the gas-liquid mixture outlet, and is used to uniformly collect and export the gas-liquid mixture.

7. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to any one of claims 1 to 6, characterized in that, In the honeycomb biomimetic flow field region, the radius R of the inscribed circle of the regular hexagonal flow channel unit gradually decreases along the direction from the electrolyte inlet to the gas-liquid mixture outlet.

8. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 1, characterized in that, The overall length of the flow channel structure is 65 mm to 75 mm, and the overall width is 36 mm to 40 mm.

9. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 1, characterized in that, The inner wall surface of the regular hexagonal flow channel unit is hydrophilic to reduce the flow resistance of the electrolyte in the flow channel and promote the separation and discharge of the gas and liquid phases.

10. The bipolar plate flow channel structure of the proton exchange membrane electrolyzer based on honeycomb bionics according to claim 6, characterized in that, The cross-sectional area of ​​the flow channel in the inlet distribution zone gradually increases from the end connected to the electrolyte inlet to the end connected to the honeycomb biomimetic flow field zone, exhibiting a diffusion shape; the cross-sectional area of ​​the flow channel in the outlet collection zone gradually decreases from the end connected to the honeycomb biomimetic flow field zone to the end connected to the gas-liquid mixture outlet, exhibiting a contraction shape.

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