Thin PEM electrolytic bath bipolar plate and electrolytic bath

Abstract

The utility model discloses a thin PEM electrolytic bath bipolar plate and an electrolytic bath. The thin PEM electrolytic bath bipolar plate comprises a plate body, and a gas circulation network is arranged on the side surface of a cathode of the plate body; the gas circulation network comprises a flow dividing part arranged in the middle of the plate body and flow guiding parts symmetrically arranged on the two sides of the flow dividing part, the flow dividing part comprises two flow dividing areas symmetrically arranged relative to the longitudinal center line of the plate body, each flow guiding part comprises a flow guiding area, and the flow dividing areas and the flow guiding areas are both air flow channels formed in the surface of the plate body. And the gas flow channels are arranged towards the hydrogen outlet areas and are used for guiding hydrogen generated on the cathode side towards the hydrogen outlet areas on the two sides, and a separation ridge arranged in a protruding mode is formed between the two flow dividing areas. By shortening the flow distance of hydrogen, the flow guide effect of a gas circulation network is not influenced under the condition of reducing the depth of a gas flow channel, so that the requirement on the thickness of the bipolar plate can be reduced, and the thinning design of the bipolar plate is realized.

Description

Technical Field

[0001] This utility model belongs to the technical field of hydrogen production equipment, specifically relating to a thin PEM electrolyzer bipolar plate and electrolyzer. 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] Patent document CN223738158U discloses an electrolytic cell bipolar plate and an electrolytic cell with microporous flow channels. A jet is formed by setting a microporous flow channel network on the anode side surface and a gas flow channel network is set on the cathode side surface to form a gas guiding channel. The setting of the microporous flow channel network and the gas flow channel network requires the bipolar plate to have a certain thickness. The large thickness of the bipolar plate affects the performance and cost of the electrolytic cell. Utility Model Content

[0004] The purpose of this invention is to provide a thin PEM electrolytic cell bipolar plate and an electrolytic cell to solve the problem of large bipolar plate thickness.

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

[0006] A thin PEM electrolyzer bipolar plate includes a plate body, with an inlet water area and an outlet water area respectively located at both ends of the plate body along its length, and a hydrogen outlet area respectively located at both ends of the plate body along its width. A microporous flow channel network is provided on the anode side surface of the plate body, and a gas flow network is provided on the cathode side surface of the plate body.

[0007] The microporous flow channel network includes multiple sets of microporous flow channel units arranged at intervals along the width of the plate. Each microporous flow channel unit is a closed channel that is connected to the inlet area and the outlet area at both ends, respectively. Several jet holes are provided at the top of the microporous flow channel unit, and the jet holes are oriented in a direction perpendicular to the anode side surface.

[0008] The gas flow network includes a flow-diverting section located in the middle of the plate and flow-guiding sections symmetrically located on both sides of the flow-diverting section. The flow-diverting section includes two flow-diverting zones symmetrically arranged relative to the longitudinal centerline of the plate. The flow-guiding section includes a flow-guiding zone. Both the flow-diverting zone and the flow-guiding zone are gas flow channels formed on the surface of the plate. The gas flow channels are all arranged towards the hydrogen outlet zone to guide the hydrogen generated on the cathode side towards the hydrogen outlet zones on both sides. A separating ridge that protrudes relative to the flow-diverting zone is formed between the two flow-diverting zones.

[0009] In some embodiments of this utility model, the diversion zone includes a plurality of diversion grooves spaced apart along the length of the plate, with partition ribs provided between the diversion grooves, and a continuously transitioning arc-shaped surface provided between the diversion grooves and the partition ribs.

[0010] In some embodiments of this invention, the width of the diversion channel gradually increases from the center of the plate to the hydrogen outlet zone.

[0011] In some embodiments of this utility model, the diversion channels located on both sides of the dividing ridge are arranged in a staggered manner along the length of the plate.

[0012] In some embodiments of this utility model, the flow guiding area is a straight groove array structure arranged side by side along the length of the plate, including multiple straight grooves, and ribs arranged in a fishbone shape are arranged at intervals on both sides of the straight grooves, and the ribs are inclined along the gas flow direction.

[0013] In some embodiments of this utility model, the flow guiding part includes a confluence region disposed between the flow guiding area and the hydrogen outlet area. The confluence region includes a honeycomb-shaped blind hole matrix and a confluence channel arranged sequentially along the airflow direction. The honeycomb-shaped blind hole matrix includes a plurality of blind hole rows spaced apart along the length direction of the plate. The confluence channel is disposed along the length direction of the plate, and a confluence gap is provided on one side wall of the confluence channel facing the honeycomb-shaped blind hole matrix, and an outlet gap is provided on the other side wall.

[0014] In some embodiments of this utility model, both the confluence gap and the outflow gap are inclined toward the inside of the confluence channel.

[0015] In some embodiments of this utility model, the microporous flow channel unit includes a main flow channel arranged along the length of the plate, a plurality of primary branch flow channels spaced apart along the length of the main flow channel, short branch flow channels spaced apart on both sides of the primary branch flow channels, and jet holes arranged at the top of the short branch flow channels. The primary branch flow channels and the short branch flow channels are blind holes closed at one end. The depth of the flow channels decreases gradually from the main flow channel and the primary branch flow channels to the short branch flow channels. In addition, the depth of the main flow channel gradually decreases from the water inlet area to the water outlet area.

[0016] In some embodiments of this utility model, the depth of the gas flow channels in the diversion zone and the guide zone gradually decreases from the water outlet zone to the water inlet zone.

[0017] On the other hand, this utility model also provides an electrolytic cell that uses the aforementioned bipolar plates, wherein the bipolar plates are stacked sequentially and membrane electrode units are respectively arranged between adjacent bipolar plates.

[0018] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0019] This invention sets the gas flow network in a symmetrical layout relative to the longitudinal centerline of the bipolar plate, and guides the hydrogen generated on the cathode side to the hydrogen outlets on both sides. By shortening the hydrogen flow distance, the guiding effect of the gas flow network is not affected when the gas flow channel depth is reduced, thereby reducing the requirement for bipolar plate thickness and realizing the thinning design of the bipolar plate. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the anode side structure of the bipolar plate in an embodiment of the present invention.

[0022] Figure 2 for Figure 1 A partial schematic diagram of point A in the middle.

[0023] Figure 3 This is a schematic diagram of the cathode side structure of the bipolar plate in an embodiment of this utility model.

[0024] Figure 4 for Figure 3 A partial schematic diagram of point B in the middle.

[0025] Figure 5 This is a cross-sectional schematic diagram of the flow divider location in an embodiment of this utility model.

[0026] in:

[0027] 100. Plate; 101. Inlet; 102. Outlet; 103. Hydrogen outlet;

[0028] 11. 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.

[0029] 12. Flow divider; 121. Divider ridge; 122. Flow divider groove; 123. Divider rib;

[0030] 13. Flow guide section; 131. Straight groove; 132. Rib; 133. Honeycomb blind hole matrix; 134. Converging groove; 135. Converging notch; 136. Outflow notch. Detailed Implementation

[0031] 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.

[0032] Combining the structural features of a bipolar plate with microporous flow channels, this invention improves the structure and layout of the cathode side of the bipolar plate. The gas flow network is set as a symmetrical layout structure relative to the longitudinal center line of the bipolar plate, and the hydrogen generated on the cathode side is guided to the hydrogen outlets on both sides. By shortening the hydrogen flow distance, the guiding effect of the gas flow network is not affected when the gas flow channel depth is reduced, thereby reducing the thickness requirement of the bipolar plate and realizing the thinning design of the bipolar plate.

[0033] Reference Figure 1 and Figure 3 In some embodiments of this utility model, the thin PEM electrolytic cell bipolar plate includes a plate body 100, with an inlet water area and an outlet water area respectively provided at both ends of the plate body along the length direction of the plate body, and a hydrogen outlet area respectively provided at both ends of the plate body along the width direction of the plate body, with a microporous flow channel network provided on the anode side surface of the plate body, and a gas flow network provided on the cathode side surface of the plate body.

[0034] The microporous flow channel network includes multiple sets of microporous flow channel units 11 arranged at intervals along the width of the plate. Each microporous flow channel unit 11 is a closed channel that is connected to the inlet area and the outlet area at both ends respectively. Several jet holes 114 are provided at the top of the microporous flow channel unit, and the jet holes 114 are arranged in a direction perpendicular to the anode side surface.

[0035] The gas flow network includes a flow divider 12 located in the middle of the plate and flow guides 13 symmetrically located on both sides of the flow divider. The flow divider 12 includes two flow divider zones symmetrically arranged relative to the longitudinal centerline of the plate. The flow guides 13 include a flow guide zone. Both the flow divider zone and the flow guide zone are gas flow channels formed on the surface of the plate. The gas flow channels are both arranged in the direction of the hydrogen outlet zone, which is used to guide the hydrogen generated on the cathode side in the direction of the hydrogen outlet zone on both sides. A partition ridge 121 protruding relative to the flow divider zone is formed between the two flow divider zones.

[0036] By forming a partition ridge along the longitudinal centerline of the plate on the cathode side, the cathode side is divided into independent gas flow areas on both sides. The two independent gas flow areas cooperate with the hydrogen outlet areas on both sides to form a double-sided suction structure. While ensuring the same hydrogen guiding effect, the depth of the gas flow channel can be reduced, and the thickness requirement of the bipolar plate when forming the gas flow channel on the bipolar plate can be reduced, thereby achieving the effect of bipolar plate thinning.

[0037] In some embodiments, the diversion zone includes a plurality of diversion grooves 122 spaced apart along the length of the plate, with partition ribs 123 provided between the diversion grooves 122, and a continuously transitioning arcuate surface provided between the diversion grooves 122 and the partition ribs 121. (Refer to...) Figure 5 The flow divider 122 is a groove structure machined on the surface of the plate, and the depth of the flow divider 122 is set to 0.05-0.1mm.

[0038] like Figure 4 As shown, the width of the diversion channel 122 gradually increases from the center of the plate to the hydrogen outlet zone, so that the diversion channel has a funnel-shaped structure along the gas flow direction, so as to play a better role in diverting the gas in the middle to the corresponding guide zone, and forming a stable airflow towards the hydrogen outlet zone on both sides of the dividing ridge.

[0039] The flow dividers 122 located on both sides of the dividing ridge are arranged in a staggered manner along the length of the plate. The staggered arrangement of the flow dividers 122 on both sides of the dividing ridge is intended to achieve a better flow divider effect on both sides and avoid mutual interference between the fluids on both sides in the flow divider area.

[0040] like Figure 3 and Figure 4 As shown, the flow guiding area is a straight groove array structure arranged side by side along the length of the plate, including multiple straight grooves 131. Ribs 132 arranged in a fishbone shape are arranged at intervals on both sides of the straight grooves 131. The ribs 132 are inclined along the gas flow direction.

[0041] The width of the straight groove is set to 0.5-0.6 mm, the groove depth is set to 0.05-0.1 mm, and the ridge width formed between adjacent straight grooves is set to 0.3-0.4 mm to reduce contact resistance. The ribs are inclined in the direction of gas flow, with an inclination angle of 20°-30° and a spacing of 1 mm between adjacent ribs.

[0042] The inlet of the straight groove is connected to the outlet of the diversion groove to transport and guide the diverted gas, forming airflow along the direction of the straight groove on the corresponding side. The guide zone adopts a three-dimensional fishbone-microrib structure composed of straight groove array and ribs, which can form a secondary transverse vortex during gas transport, and can well meet the requirements of low-pressure hydrogen discharge.

[0043] In some embodiments, such as Figure 3 The flow guiding section 13 also includes a confluence zone disposed between the flow guiding zone and the hydrogen outlet zone. The confluence zone includes a honeycomb-shaped blind hole matrix 133 and a confluence groove 134 arranged sequentially along the airflow direction.

[0044] The honeycomb-shaped blind hole matrix 133 includes several rows of blind holes spaced apart along the length of the plate. The blind hole array includes multiple blind holes arranged along the length direction, with the diameter of the blind holes decreasing sequentially in this direction. The diameter of the blind holes is set to 0.8mm-1.2mm, and the depth of the blind holes is set to 0.05-0.1mm. By forming a honeycomb-shaped blind hole matrix at the straight groove outlet, a low-pressure suction effect is created at the straight groove outlet position, which homogenizes the uneven transverse flow at the end of the straight groove, reducing the overall pressure drop and flow unevenness.

[0045] The confluence channel 134 is arranged along the length of the plate, and a confluence notch 135 is provided on the side wall facing the honeycomb blind hole matrix to allow airflow to gather within the confluence channel. An outflow notch 136 is provided on the other side wall. Both the confluence notch 135 and the outflow notch 136 are inclined towards the inside of the confluence channel to better guide and discharge the airflow. The confluence channel can collect and rectify the airflow flowing out of the straight channel, reducing the lateral velocity difference.

[0046] The manifold 134 is a semi-open shallow groove structure with a width of 2-3mm and a groove depth of 0.05mm-0.1mm, which is less than the depth of the straight groove at the corresponding position.

[0047] Reference Figure 1 and Figure 2Along the length of the plate, a water inlet area is provided at one end of the plate and a water outlet area is provided at the other end of the plate. One or more water inlets 101 are arranged side by side in the water inlet area and one or more water outlets 102 are arranged side by side in the water outlet area. Along the width of the plate, hydrogen outlet areas are provided at both ends of the plate, and one or more hydrogen outlets 103 are provided in each hydrogen outlet area.

[0048] The microporous flow channel unit 11 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, and a plurality of short branch flow channels 113 arranged at intervals on both sides of the primary branch flow channels 112. Each short branch flow channel 113 is provided with a jet hole 114 at its top. The jet hole 114 is arranged in a direction perpendicular to the anode side surface, so as to jet the water vertically toward the membrane electrode unit located above it.

[0049] 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.

[0050] like Figure 1 and Figure 2 The main channel 111 includes an inlet section 111a, a transition section 111b, and an outlet section 111c connected in sequence. 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 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 transition section gradually increases from the inlet section to the outlet section.

[0051] The inlet section 111a of the main channel adopts a necking structure, and the flow area gradually decreases 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.

[0052] 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.

[0053] 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, if the length of the primary branch channel is set to 8 mm, the corresponding length of the short branch channel is set to 1 mm, and the interval between adjacent short branch channels is set to 1 mm.

[0054] All primary branch channels 112 are located on the same side of the main channel 111, and all primary branch channels 112 are inclined towards 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, the angle between the primary branch channels 112 and the main channel is set to 30°.

[0055] The width and depth of the transition section of the main flow channel 111, the first-order branch flow channel 112, and the short branch flow channel 113 gradually decrease. For example, the width of the first-order 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 set at the orifice to form local turbulence at the orifice.

[0056] In some embodiments, the structure of the cathode-side gas flow network is further improved by taking into account the structural feature of the microporous flow channel unit with a gradually changing depth along the length of the plate. Specifically, the depth of the gas flow channels in the diversion zone and the guide zone gradually decreases from the water outlet zone to the water inlet zone. For example, near the water inlet zone, since the depth of the main flow channel is relatively large, for example, 0.3 mm, the depth of the gas flow channel on the cathode side at the corresponding position is set to be relatively small, for example, 0.05 mm; while near the water outlet zone, the depth of the main flow channel is relatively small, for example, 0.2 mm, and the depth of the gas flow channel on the cathode side at the corresponding position is set to be relatively large, for example, 0.1 mm, so that the depth of the gas flow channel gradually changes from 0.05 mm to 0.1 mm along the length of the plate. In this way, the requirement for the thickness of the bipolar plate can be reduced while ensuring the function of the gas flow network.

[0057] Accordingly, to accommodate the structure of the gradually changing depth of the airflow channel on the cathode side, the layout density of the airflow channel can be differentiated. For example, a more densely arranged airflow channel can be designed in the area with a smaller depth to compensate for the impact of the depth change on the airflow at each position.

[0058] On the other hand, this utility model also provides an electrolytic cell that uses the bipolar plates in the above embodiments, with the bipolar plates stacked in sequence and membrane electrode units respectively disposed between adjacent bipolar plates.

[0059] 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. A thin PEM cell bipolar plate, characterized in that, The bipolar plate comprises a plate body, water inlet and outlet areas arranged at both ends of the plate body in the length direction, hydrogen outlet areas arranged at both ends of the plate body in the width direction, a microporous flow channel network arranged on the anode side surface of the plate body, and a gas flow network arranged on the cathode side surface of the plate body. The microporous flow channel network comprises a plurality of groups of microporous flow channel units arranged at intervals in the width direction of the plate body, the microporous flow channel units are closed channels respectively communicating with the water inlet and outlet areas at both ends, and a plurality of jet holes are arranged on the top of the microporous flow channel units and arranged towards the direction perpendicular to the anode side surface. The gas flow network comprises a flow dividing part arranged in the middle of the plate body and flow guiding parts symmetrically arranged on both sides of the flow dividing part, the flow dividing part comprises two flow dividing areas symmetrically arranged with respect to the longitudinal center line of the plate body, the flow guiding part comprises a flow guiding area, the flow dividing area and the flow guiding area are both gas flow channels formed on the surface of the plate body, and the gas flow channels are both arranged towards the hydrogen outlet area for guiding the hydrogen generated on the cathode side to the hydrogen outlet area on both sides, and a separation ridge is arranged between the two flow dividing areas and protrudes with respect to the flow dividing area.

2. The thin PEM cell bipolar plate of claim 1, wherein The flow dividing area comprises a plurality of flow dividing grooves arranged at intervals in the length direction of the plate body, and a separation rib is arranged between the flow dividing grooves, and an arc-shaped surface is arranged between the flow dividing grooves and the separation ridge.

3. A thin PEM cell bipolar plate according to claim 2, characterized in that From the center of the plate body to the direction of the hydrogen outlet area, the width of the flow dividing groove gradually increases.

4. The thin PEM cell bipolar plate of claim 2, wherein The flow dividing grooves on both sides of the separation ridge are arranged in opposite staggered manner in the length direction of the plate body.

5. A thin PEM cell bipolar plate according to claim 1 or 2, characterised in that The flow guiding area is a straight groove array structure arranged side by side at intervals in the length direction of the plate body, comprises a plurality of straight grooves, and a rib arranged in a fishbone shape is arranged at intervals on the side walls on both sides of the straight grooves, and the rib is arranged obliquely along the gas flow direction.

6. A thin PEM cell bipolar plate according to claim 1 or 2, characterised in that The flow guiding part comprises a flow converging area arranged between the flow guiding area and the hydrogen outlet area, the flow converging area comprises a honeycomb-shaped blind hole matrix and a flow converging groove arranged in sequence along the gas flow direction, the honeycomb-shaped blind hole matrix comprises a plurality of blind hole queues arranged at intervals in the length direction of the plate body, the flow converging groove is arranged in the length direction of the plate body, and a flow converging notch is arranged on one side wall of the flow converging groove towards the honeycomb-shaped blind hole matrix, and a flow outlet notch is arranged on the other side wall.

7. A thin PEM cell bipolar plate according to claim 6, wherein The flow converging notch and the flow outlet notch are both arranged obliquely towards the inside of the flow converging groove.

8. The thin PEM cell bipolar plate of claim 1, wherein The microporous flow channel unit comprises a main flow channel arranged in the length direction of the plate body, a plurality of first branch flow channels arranged at intervals in the length direction of the main flow channel, short branch flow channels arranged at intervals on both sides of the first branch flow channels, jet holes arranged on the top of the short branch flow channels, and the first branch flow channels and the short branch flow channels are blind holes with one end closed; the depth of the flow channel gradually decreases from the main flow channel, the first branch flow channel to the short branch flow channel, and the depth of the main flow channel gradually decreases from the water inlet area to the water outlet area.

9. The thin PEM cell bipolar plate of claim 8, wherein, From the water outlet area to the water inlet area, the depth of the gas flow channels of the flow dividing area and the flow guiding area gradually decreases.

10. An electrolytic cell characterized by The bipolar plates of any one of claims 1-9 are sequentially stacked, and membrane electrode units are arranged between adjacent bipolar plates.

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