Electrolytic tank bipolar plate with micropore flow channel and electrolytic tank

Abstract

The utility model discloses an electrolytic bath bipolar plate with micropore flow channels and an electrolytic bath, a micropore flow channel network is arranged on the side surface of an anode of a plate body, and the micropore flow channel network comprises a plurality of groups of micropore flow channel units which are arranged at intervals along the width direction of the plate body; each micropore flow channel unit comprises a main flow channel arranged in the length direction of the plate body and a plurality of first-stage branch flow channels arranged in the length direction of the main flow channel at intervals, a plurality of short branch flow channels are arranged on the two sides of each first-stage branch flow channel at intervals, and a jet hole is formed in the top of each short branch flow channel. The jet flow holes are formed in the direction perpendicular to the side surface of the anode, the length of the short branch runner is smaller than that of the first-stage branch runner, and the short branch runner is perpendicular to the first-stage branch runner. And the microporous flow channel network adopts a structure of combining tree fractal and T-shaped nodes, so that the mass transfer uniformity of water flow in the microporous flow channels can be improved, and the water-membrane contact efficiency is improved, thereby ensuring the hydrogen production efficiency of the bipolar plate.

Description

Technical Field

[0001] This utility model belongs to the technical field of hydrogen production equipment, specifically relating to a bipolar plate and an electrolyzer with microporous flow channels. Background Technology

[0002] PEM (Proton Exchange Membrane) water electrolysis for hydrogen production utilizes a polymer electrolyte membrane to decompose water into hydrogen and oxygen, offering advantages such as high efficiency, compact design, and rapid response. PEM bipolar plates are a crucial component of the proton exchange membrane electrolyzer, supporting current transmission and the water electrolysis reaction. They are typically made of titanium alloys or other corrosion-resistant metals, possessing good electrical conductivity and mechanical strength.

[0003] Currently, the flow field design in PEM hydrogen production technology directly affects the hydrogen production efficiency. Existing PEM hydrogen production flow field bipolar plates mainly adopt structures such as parallel flow channels and serpentine flow channels. These flow field structures have the following problems: the water / oxygen mass transfer boundary layer on the anode side is thick, resulting in local overheating and severe bubble retention; when electrolyzed water flows in the flow channel, it is easy to form laminar flow, which leads to insufficient contact with the proton exchange membrane surface and reduces the reaction efficiency; in the traditional flow field structure, the contact area between electrolyzed water and the reaction surface is limited, and the residence time of electrolyzed water on the reaction surface is short, which is not conducive to improving hydrogen production efficiency. Utility Model Content

[0004] The purpose of this invention is to provide an electrolytic cell bipolar plate and an electrolytic cell with microporous flow channels, so as to solve the above-mentioned technical problems in the design of the anode-side flow channels in existing bipolar plates.

[0005] This utility model is achieved through the following technical solution:

[0006] An electrolytic cell bipolar plate with microporous flow channels, including the plate body;

[0007] Along the length of the plate, water inlet and water outlet are respectively provided at both ends of the plate, and along the width of the plate, hydrogen outlet is respectively provided on both sides of the plate.

[0008] The anode side surface of the plate is provided with a microporous flow channel network, which includes multiple sets of microporous flow channel units arranged at intervals along the width direction of the plate.

[0009] The microporous flow channel unit includes a main flow channel arranged along the length of the plate and multiple primary branch flow channels spaced apart along the length of the main flow channel. Multiple short branch flow channels are spaced apart on both sides of the primary branch flow channels. Each short branch flow channel has a jet hole at its top, and the jet hole is oriented perpendicular to the anode side surface. The main flow channel is a through hole with both ends connected to the inlet and outlet water areas, respectively. The primary branch flow channel is a blind hole with one end connected to the main flow channel and the other end closed. The short branch flow channel is a blind hole with one end connected to the primary branch flow channel and the other end closed. The length of the short branch flow channel is less than the length of the primary branch flow channel.

[0010] In some embodiments, the length of the short branch channel is 1 / 8 to 1 / 10 of the length of the primary branch channel.

[0011] In some embodiments, the short branch channels located on both sides of the primary branch channel are arranged in an alternating manner.

[0012] In some embodiments, among the short branch channels arranged opposite to each other on two adjacent primary branch channels, the short branch channels on one primary branch channel are respectively fitted into the gap between two adjacent short branch channels on the other primary branch channel.

[0013] In some embodiments, the short branch flow channel and the primary branch flow channel are arranged perpendicular to each other.

[0014] In some embodiments, the primary branch channels are all located on the same side of the main channel, and the primary branch channels are all inclined to the main channel in the direction of water flow, and the angle between the primary branch channels and the main channel is 30° to 45°.

[0015] In some embodiments, the main channel includes an inlet section, a transition section, and an outlet section connected in sequence;

[0016] The inlet section is connected to the water inlet area at one end and to the transition section at the other end, and the width of the inlet section gradually decreases from the water inlet area to the transition section.

[0017] One end of the outlet section is connected to the transition section, and the other end is connected to the water outlet area;

[0018] The flow area of ​​the transition section gradually increases from the inlet section to the outlet section.

[0019] In some embodiments, the width of the flow channel gradually increases and the depth of the flow channel gradually decreases from the inlet section to the outlet section.

[0020] In some embodiments, the width and depth of the transition section of the main flow channel, the first-level branch flow channel, and the short branch flow channel gradually decrease.

[0021] On the other hand, this utility model also provides an electrolytic cell, including an electrolytic cell bipolar plate;

[0022] Multiple bipolar plates of electrolytic cells are stacked in sequence, and a first carbon paper, a proton exchange membrane and a second carbon paper are arranged in sequence between adjacent bipolar plates of electrolytic cells.

[0023] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0024] This invention features a microporous flow channel network on the anode side surface. The microporous flow channel network adopts a structure combining a tree-like fractal and T-shaped nodes. Short branch channels are set on the primary branch channels branching from the main channel, and multiple T-shaped nodes are formed on both sides of the primary branch channels. The T-shaped nodes generate lateral swirling flow, which can improve the mass transfer uniformity of water flow in the microporous channels and improve the water-film contact efficiency without increasing the pressure drop of the main channel, thereby ensuring the hydrogen production efficiency of the bipolar plate.

[0025] The microporous flow channel network used has the characteristics of simple structure, which greatly reduces the molding difficulty of bipolar plates and reduces the processing cost of this type of bipolar plate with microporous jet channels.

[0026] By optimizing the microporous channel network structure and utilizing the arrangement characteristics of short branch channels on the primary branch channels, the density of jet holes on the anode side surface is increased without affecting the mass transfer efficiency of the microporous channel network. This ensures that the jet holes can uniformly cover the entire active area on the anode side, effectively guaranteeing the hydrogen production efficiency of the bipolar plate. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the anode side structure of the bipolar plate in an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the layout structure of the short branch flow channel in the anode-side microporous flow channel unit of this utility model embodiment.

[0030] Figure 3 This is a schematic diagram of the cathode side structure of the bipolar plate in an embodiment of this utility model.

[0031] Figure 4 This is a partial schematic diagram of the three-dimensional fishbone-microrib structure on the cathode side of the bipolar plate in an embodiment of this utility model.

[0032] in:

[0033] 11. Plate body; 12. Inlet; 13. Outlet; 14. Hydrogen outlet;

[0034] 110. Micro-orifice flow channel unit; 111. Main flow channel; 111a. Inlet section; 111b. Gradient section; 111c. Outlet section; 112. First-level branch flow channel; 113. Short branch flow channel; 114. Jet orifice.

[0035] 121. Flow guide channel; 122. Straight channel; 123. Rib; 124. Blind hole matrix; 125. Combination channel; 126. Air inlet; 127. Multi-hole outlet. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0037] Reference Figure 1 and Figure 2 In some embodiments of this utility model, the bipolar plate of the electrolytic cell with microporous channels includes a plate body 11. Along the length of the plate body, a water inlet area is provided at one end of the plate body, and a water outlet area is provided at the other end of the plate body. One or more water inlets 12 are arranged side by side in the water inlet area, and one or more water outlets 13 are arranged side by side in the water outlet area. The water inlet area and the water outlet area are diagonally arranged on the plate body. Along the width of the plate body, hydrogen outlet areas are provided on both sides of the plate body 11, and one or more hydrogen outlets 14 are provided in each hydrogen outlet area. The two hydrogen outlet areas are diagonally arranged on the plate body.

[0038] A microporous flow channel network is provided on the anode side surface of the plate, and the microporous flow channel network includes multiple sets of microporous flow channel units 110 arranged at intervals along the width direction of the plate.

[0039] Specifically, the microporous flow channel unit 110 includes a main flow channel 111 arranged along the length of the plate, a plurality of primary branch flow channels 112 arranged at intervals along the length of the main flow channel 111, a plurality of short branch flow channels 113 arranged at intervals on both sides of the primary branch flow channels 112, and a jet hole 114 arranged at the top of each short branch flow channel 113. The jet hole 114 is arranged in a direction perpendicular to the anode side surface, so as to vertically jet the water flow toward the proton exchange membrane located above it.

[0040] The main channel 111 is a through hole that connects to the inlet area and the outlet area at both ends, respectively. The primary branch channel 112 is a blind hole that connects to the main channel at one end and is closed at the other end. The short branch channel 113 is a blind hole that connects to the primary branch channel at one end and is closed at the other end. The length of the short branch channel 113 is less than the length of the primary branch channel, and the short branch channel 113 is perpendicular to the primary branch channel 112.

[0041] The water flow enters the primary branch channel from the main channel and then immediately flows into the various short branch channels. Due to the perpendicular structure of the short branch channels and the branch channels, the water flow undergoes a 90° turn during its rapid entry from the primary branch channel into the short branch channels, generating a transverse velocity wind component perpendicular to the original flow direction. This transverse flow directly impacts the sidewalls of the short branch channels, disrupting the original axial boundary layer and forming a transverse shear flow. The transverse shear flow is obstructed at the closed end of the short branch channel, resulting in instantaneous separation and turbulence, forming a transverse vortex within the short branch channel. This transverse vortex moves along the length of the short branch channel and periodically sweeps across the top jet orifice to increase the local Reynolds number at the jet orifice outlet.

[0042] Transverse eddies can alter the concentration boundary layer between the top of the short branch channel and the water film, and continuously transport the water flow laterally to the area below the jet orifice, reducing the interfacial concentration gradient, thereby improving the mass transfer uniformity of the medium in the microporous channel and increasing the water-film contact efficiency.

[0043] In some embodiments, the main channel 111 includes an inlet section 111a, a transition section 111b, and an outlet section 111c connected in sequence.

[0044] The inlet section 111a is connected to the water inlet area at one end and to the transition section 111b at the other end. The width of the flow channel in the inlet section gradually decreases from the water inlet area to the transition section. The outlet section 111c is connected to the transition section 111b at one end and to the water outlet area at the other end. The flow area of ​​the flow channel in the transition section gradually increases from the inlet section to the outlet section.

[0045] The inlet section 111a of the main channel adopts a constriction structure, with the flow area gradually decreasing from the inlet to the outlet, forming a local high pressure at the outlet of the inlet section to ensure the inlet static pressure of each primary branch channel. The transition section of the main channel adopts a funnel-shaped wedge-shaped transition structure, which gradually increases the flow area of ​​the channel, making the flow velocity reduction controllable. A certain static pressure can still be maintained at the outlet of the transition section, avoiding the problem of insufficient water flow at the outlet of the main channel.

[0046] The transition section 111b gradually increases in width and decreases in depth from the inlet section to the outlet section. For example, the width of the transition section gradually increases from 1.2 mm to 2.0 mm, and the depth gradually decreases from 0.3 mm to 0.2 mm, so that the increase in flow area is less than 50%, thereby controlling the flow rate reduction.

[0047] In some embodiments, the length of the short branch channel 113 is 1 / 8 to 1 / 10 of the length of the primary branch channel 112. For example, the length of the primary branch channel is set to 8 mm, and correspondingly, the length of the short branch channel is set to 1 mm, with a spacing of 1 mm between adjacent short branch channels. By reducing the length of the short branch channels, the pressure loss of the water flow when flowing into the short branch channels is reduced, allowing the water flow to be ejected from the jet orifice to the proton exchange membrane, ensuring sufficient contact between the water flow and the proton exchange membrane.

[0048] To increase the density of the jet orifices, short stub channels 113 are provided on both sides of the primary branch channel 112. Because the short stub channels are short and perpendicular to the primary branch channel, the multiple short stub channels on both sides do not cause a large pressure drop. The short stub channels on both sides are arranged asymmetrically in a staggered manner to improve the distribution of the jet orifices and reduce water flow pressure drop loss.

[0049] In some embodiments, refer to Figure 2 In two adjacent primary branch channels 112, short branch channels 113 are arranged opposite each other, with one primary branch channel 112's short branch channel 113 respectively fitting into the gap between two adjacent short branch channels 113 in the other primary branch channel. In this way, the primary branch channels can form a denser arrangement on the main channel, optimize the distribution of jet orifices on the microporous channel network, and ensure that the jet orifices fully cover the entire active area on the anode side.

[0050] In some embodiments, all primary branch channels 112 are located on the same side of the main channel 111, and all primary branch channels 112 are inclined toward the main channel in the direction of water flow, with the angle between the primary branch channels 112 and the main channel 111 being 30° to 45°. For example, setting the angle between the primary branch channels 112 and the main channel to 30° ensures sufficient water pressure for the water entering the primary branch channels when increasing the arrangement density of the primary branch channels.

[0051] In some embodiments, the width and depth of the transition section of the main flow channel 111, the first-level branch flow channel 112, and the short branch flow channel 113 gradually decrease. For example, the width of the first-level branch flow channel is set to 0.6 mm and the depth to 0.2 mm; correspondingly, the width of the short branch flow channel can be set to 0.4-0.5 mm and the depth to 0.1 mm. The diameter of the jet orifice is set to 0.2 mm, and a 30° chamfer is provided at the orifice to form local turbulence at the orifice.

[0052] In some embodiments, refer to Figure 3 and Figure 4 A gas flow network is provided on the cathode side surface of the plate 11. The gas flow network includes a gas inlet section, a gas transmission section and a gas outlet section arranged sequentially along the gas flow direction. The gas inlet section, gas transmission section and gas outlet section are arranged from one hydrogen outlet zone to another hydrogen outlet zone.

[0053] The gas inlet section is provided with several parallel guide channels 121. The guide channels 121 have a structure in which the width gradually decreases along the flow direction. The guide channels are generally funnel-shaped and are open channel structures set on the cathode side of the plate. The guide channels 121 also adopt a gradual structure in the depth direction. For example, the channel depth at the inlet is set to 0.3 mm and the channel depth at the outlet is set to 0.1 mm.

[0054] The gradient structure design of the gas inlet section guide channel can rectify and accelerate the hydrogen-rich fluid flowing in from the anode side, preventing hydrogen from stagnating at the inlet end. By accelerating the hydrogen, it can quickly remove bubbles and prevent airflow blockage at the inlet section.

[0055] The gas transmission section employs a parallel straight groove array structure with a three-dimensional fishbone-microrib structure, comprising multiple straight grooves 122 arranged side by side, with the inlet of each groove 122 connected to the outlet of the guide groove. Fishbone-shaped ribs 123 are evenly spaced on the side walls of each straight groove 122, inclined at an angle of 20°-30° along the gas flow direction, with a 1mm interval between adjacent ribs. The groove width is 0.5-0.6mm, the groove depth is 0.1mm, and the ridge width formed between adjacent straight grooves is 0.3-0.4mm to reduce contact resistance.

[0056] The length of the straight groove covers 70% of the active area on the cathode side. The parallel straight groove array structure with a three-dimensional fishbone-microrib structure in the transmission section can form a secondary transverse vortex during gas transportation, ensuring that hydrogen and carbon paper surface can fully interact without water accumulation.

[0057] The gas outlet section is designed as a gradient porous suction cup confluence zone, with a honeycomb-shaped blind hole matrix arranged on the opposite end of the plate from the inlet section. The blind hole matrix 124 has a gradient structure with apertures ranging from 0.8mm to 1.2mm in the direction of airflow, and the porosity of the outlet section is set to 55%-70%. The orifice openings are chamfered at a certain angle, such as 30°, to create a low-pressure suction effect, homogenizing the uneven transverse flow at the end of the straight channel and reducing the overall pressure drop and flow unevenness.

[0058] A manifold 125 is provided between the honeycomb blind hole matrix and the second hydrogen outlet zone. The manifold 125 is arranged perpendicularly to the parallel straight channels. The outlet ends of the parallel straight channels flow into the manifold through the inlet 126 provided on the manifold, forming an accumulation in the manifold. A porous outlet 127 is provided on the other side of the manifold opposite to the parallel straight channels to collect and rectify the hydrogen flowing out of the straight channels, reducing the lateral velocity difference.

[0059] The manifold 125 is a semi-open shallow tank structure with a width of 2-3 mm. The bottom of the manifold 125 is set to be 0.05 mm lower than the straight tank, forming a water-hydrogen gravity separation in the manifold. The separated liquid water is discharged along the manifold.

[0060] Since the cathode side mainly serves to guide hydrogen flow, it does not need to withstand the water flow pressure on the anode side. An open straight groove can meet the requirements for low-pressure hydrogen discharge. The three-dimensional fishbone-microrib structure can be directly laser-ablated and formed in the straight groove.

[0061] On the other hand, this utility model also provides an electrolytic cell, including an electrolytic cell bipolar plate;

[0062] Multiple bipolar plates of electrolytic cells are stacked in sequence, with adjacent bipolar plates of electrolytic cells being deflected by 180°, and the water inlet area of ​​one bipolar plate of electrolytic cells being opposite to the water outlet area of ​​another bipolar plate of electrolytic cells; a first carbon paper, a proton exchange membrane and a second carbon paper are sequentially arranged between adjacent bipolar plates of electrolytic cells.

[0063] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", and "outer" used to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0064] Furthermore, the use of terms such as "horizontal" or "vertical" in the description of this utility model does not imply that the component is required to be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0065] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 utility model in light of the specific circumstances.

[0066] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. An electrolyser bipolar plate having micro-porous flow channels, characterised in that, The plate body comprises: An inlet water area and an outlet water area are respectively arranged at both ends of the plate body along the length direction of the plate body, and a hydrogen outlet area is respectively arranged at both sides of the plate body along the width direction of the plate body; A microporous flow channel network is arranged on the anode side surface of the plate body, and the microporous flow channel network comprises a plurality of groups of microporous flow channel units arranged at intervals along the width direction of the plate body; The microporous flow channel unit comprises a main flow channel arranged along the length direction of the plate body, a plurality of first branch flow channels arranged at intervals along the length direction of the main flow channel, and a plurality of short branch flow channels arranged at intervals on both sides of the first branch flow channel, respectively, each short branch flow channel is provided with a jet hole at the top, the jet hole is arranged towards the direction perpendicular to the anode side surface, the main flow channel is a through hole with two ends respectively communicating with the inlet water area and the outlet water area, the first branch flow channel is a blind hole with one end communicating with the main flow channel and the other end being closed, and the short branch flow channel is a blind hole with one end communicating with the first branch flow channel and the other end being closed, and the length of the short branch flow channel is less than the length of the first branch flow channel.

2. The electrolyser bipolar plate having micro-channeled flow paths according to claim 1, characterised in that, The length of the short branch flow channel is 1 / 8-1 / 10 of the length of the first branch flow channel.

3. The electrolyser bipolar plate having micro-channeled flow paths according to claim 1, characterised in that, The short branch flow channels on both sides of the first branch flow channel are relatively staggered.

4. The electrolyser bipolar plate having micro-channeled flow paths according to claim 1, wherein, Among the short branch flow channels arranged on the opposite sides of the two adjacent first branch flow channels, the short branch flow channels on one first branch flow channel are respectively fitted into the gaps between the two adjacent short branch flow channels on the other first branch flow channel.

5. An electrolyser bipolar plate having micro-channeled flow paths according to any one of claims 1 or 2 or 3 or 4 characterised in that, The short branch flow channel and the first branch flow channel are arranged perpendicular to each other.

6. An electrolyser bipolar plate having micro-channeled flow paths according to any one of claims 1 or 2 or 3 or 4 characterised in that, The first branch flow channels are all located on the same side of the main flow channel, and the first branch flow channels are all arranged inclined between the main flow channel in the water flow direction, and the included angle between the first branch flow channel and the main flow channel is 30°-45°.

7. The electrolyser bipolar plate having micro-channeled flow paths according to claim 1, wherein, The main flow channel comprises an inlet section, a gradual change section and an outlet section connected in sequence; The inlet section is in communication with the inlet water area at one end and connected with the gradual change section at the other end, and the flow channel width of the inlet section gradually decreases from the inlet water area to the gradual change section; The outlet section is connected with the gradual change section at one end and in communication with the outlet water area at the other end; The flow area of the flow channel of the gradual change section gradually increases from the inlet section to the outlet section.

8. The electrolyser bipolar plate having micro-channeled flow paths according to claim 7, characterised in that, The width of the flow channel of the gradual change section gradually increases and the depth of the flow channel gradually decreases from the inlet section to the outlet section.

9. The electrolyser bipolar plate having micro-channeled flow paths according to claim 7, characterised in that, The flow channel width and depth of the gradual change section, the first branch flow channel and the short branch flow channel of the main flow channel gradually decrease.

10. An electrolytic cell characterized by The electrolytic cell bipolar plate comprises: A plurality of electrolytic cell bipolar plates are arranged in sequence, and a first carbon paper, a proton exchange membrane and a second carbon paper are arranged in sequence between adjacent electrolytic cell bipolar plates.

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