Bipolar plate for water electrolyser with annular water inlet

Abstract

The invention discloses a bipolar plate for a water electrolyser with an annular water inlet, and relates to the technical field of water electrolysis hydrogen production, the bipolar plate comprises a pole frame area and a pole plate reaction area, the pole frame area is internally provided with an electrolyte flow field, a diversion trench, a liquid inlet and a liquid outlet, and the electrolyte flow field is of an annular structure surrounding the center of the bipolar plate; the annular structure enables water flow to uniformly enter each area of the polar plate reaction area through the diversion trenches, an annular flow channel is arranged on the outer side of the liquid inlet and is divided into an inner flow channel and an outer flow channel, the outer flow channel is communicated with the liquid inlet, and the diversion trenches communicated with the inner flow channel are uniformly distributed in the inner flow channel. The water inlets are arranged around the bipolar plate, so that water flow is uniformly distributed, the cooling efficiency is improved, the phenomenon of local overheating or insufficient cooling is reduced, the electrolyte is uniformly distributed on active sites on the surface of the motor, the electrolytic efficiency of the electrolytic water tank is improved under the high current density, and the device is suitable for various electrolytic tank systems; and the universality and the adaptability are improved.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen production by electrolysis of water, and in particular to a bipolar plate for a water electrolyzer with an annular water inlet. Background Art

[0002] Water electrolysis is an electrochemical process that decomposes water into hydrogen and oxygen by applying electrical energy in the presence of a catalyst. There are currently four different types of water electrolysis technology routes, based on the operating temperature and the type of electrolyte used: alkaline water electrolysis, proton exchange membrane water electrolysis, anion exchange membrane water electrolysis, and solid oxide water electrolysis. Compared with other water electrolysis technologies, alkaline water electrolyzer technology is the most mature, does not contain precious metals, has low cost, and has the advantage of a long working life, which makes alkaline water electrolysis technology the most important technology route in the current water electrolysis hydrogen production market.

[0003] The invention patent (CN113981479A A water electrolysis bipolar plate with internal gas-water separation function) provides a water electrolysis bipolar plate, which includes an anode plate and a cathode plate. The anode plate and / or the cathode plate are provided with one or more through holes, which is a water electrolysis bipolar plate with internal gas-water separation function that integrates gas conduction, electrical conduction and water blocking functions. However, this design does not achieve uniform coverage of the electrolyte on the electrode surface, and does not solve the problem of uneven electrolyte distribution in the upper part of a large electrolytic cell.

[0004] The invention patent (CN116254560A A water electrolysis bipolar plate) provides a water electrolysis bipolar plate, which includes an anode plate, a cathode plate and a conductive separator. The provided water electrolysis bipolar plate is a water electrolysis bipolar plate that integrates gas conduction, electrical conduction and water blocking functions and has an internal gas-water separation function. However, this design does not provide a solution to the problem of regional differences in current density and temperature field in the electrolytic cell.

[0005] The bipolar plates in alkaline water electrolyzers play multiple roles in distributing water, collecting current and supporting electrode reactions during the electrolysis process. Their design has a direct impact on electrolysis efficiency, energy consumption and the overall performance of the equipment. In traditional water electrolysis equipment, the inlet and outlet of water are usually designed at the edge of the bipolar plate. This layout may lead to uneven water flow distribution, reduced local electrolysis efficiency, and may produce high resistance losses. In addition, uneven water distribution may cause local overheating, affecting the stability and life of the device. These problems are particularly prominent in large-scale water electrolysis devices, which may limit the increase in hydrogen production and the energy efficiency optimization of the system. In addition, limited by the reaction characteristics of the electrolyzer, especially under high current density operating conditions, ion migration, mass transfer, system optimization and efficiency in the electrolyzer reaction process have multiple and critical roles, causing regional differences in the current density and temperature field of the electrolyzer, resulting in uneven water electrolysis reaction and reduced electrolysis efficiency. Therefore, it is necessary to refine the design of the key structures of the electrolyzer, improve the contact resistance and electrolyte distribution uniformity, and accelerate the rapid mass transfer of the electrolyte and the smooth transmission of bubbles. Summary of the invention

[0006] In order to improve the water flow distribution, electrolysis efficiency, energy loss, and heat dissipation performance of the system in the water electrolysis system, the present application provides a bipolar plate for a water electrolysis cell with an annular water inlet.

[0007] The bipolar plate for a water electrolyzer with an annular water inlet provided in the present application adopts the following technical solution: A bipolar plate for a water electrolyzer with an annular water inlet comprises a pole frame area and a pole plate reaction area, wherein an electrolyte flow field, a guide groove, a liquid inlet and a liquid outlet are arranged in the pole frame area, wherein the electrolyte flow field is an annular structure surrounding the center of the bipolar plate, wherein the annular structure enables water to flow evenly through the guide groove into each area of ​​the pole plate reaction area, wherein an annular flow channel is arranged outside the liquid inlet, wherein the annular flow channel is divided into an inner flow channel and an outer flow channel, wherein the outer flow channel is connected to the liquid inlet, the inner flow channel is evenly distributed, and the inner flow channel is connected to the guide groove.

[0008] By adopting the above technical solution, the annular structure allows the electrolyte to be evenly distributed on the surface of the bipolar plate, thereby significantly improving the uniformity of the electrolysis reaction and the overall electrolysis efficiency, and preventing problems such as local overreaction and overheating.

[0009] Optionally, the annular flow channel is located in the pole frame area, the arc is in the range of 180°~300°, the annular flow channel is centrally symmetrically distributed, and the liquid inlet is arranged at the intersection of the vertical center line of the outer flow channel and the annular center line.

[0010] By adopting the above technical solution, the annular flow channel of the bipolar plate allows the electrolyte to be evenly distributed in the plate reaction zone, improving the uniformity of the electrolysis reaction and the electrolysis efficiency. The arc is between 180° and 300°, ensuring the flow path of the electrolyte and avoiding local overflow or retention. The annular flow channel is symmetrically distributed about the center, further ensuring the uniform distribution of the electrolyte and enhancing the consistency of the reaction. The design of the inner and outer flow channels allows the electrolyte to flow into the plate reaction zone from multiple directions, increasing the reaction area and improving the reaction rate. The liquid inlet is set at the intersection of the vertical center line of the outer flow channel and the annular center line, and is connected to the outer flow channel, optimizing the inlet position of the electrolyte, reducing the turbulence of the liquid, allowing the electrolyte to smoothly enter the reaction zone, and improving the stability and efficiency of the reaction.

[0011] Optionally, the liquid outlet is symmetrical on both sides opposite to the plane center line of the liquid inlet, and the angle between the liquid outlet and the plane center line of the liquid inlet is in the range of 10° to 20°.

[0012] By adopting the above technical solution, it is ensured that water flows out evenly from the surface of the bipolar plate, avoiding local liquid accumulation and bubble retention, and improving the uniformity and stability of the electrolysis reaction.

[0013] Optionally, the guide groove is connected to the inner flow channel of the annular flow channel, and the guide groove is evenly distributed at 5 to 20 degrees along the center of the bipolar plate.

[0014] By adopting the above technical solution, the annular flow channel is provided with a guide groove so that the electrolyte flows from the annular flow channel to the polarization reaction zone to participate in the electrochemical reaction. The uniform distribution improves the uniformity of the electrolysis reaction and ensures that the electrolysis process is carried out with the same efficiency in the entire reaction area, thereby improving the overall electrolysis efficiency. At the same time, the uniform distribution of the guide groove helps to reduce the intensity and resistance of local reactions, reduces the energy loss in the electrolysis process, enables water molecules to reach the reaction area more effectively, and the reaction products can be quickly discharged, thereby reducing the concentration polarization and ohmic polarization in the electrolysis reaction process, and further improving the electrolysis efficiency.

[0015] Optionally, the liquid outlet is provided with a guide groove which is connected to the electrode plate reaction area, and the guide groove is symmetrically distributed along the axis of the liquid outlet.

[0016] By adopting the above technical scheme, the electrolyte and electrochemically generated gases can smoothly enter the liquid outlet from the polarization reaction zone through the guide groove, thereby achieving uniform discharge of electrolysis products, reducing local accumulation, reducing concentration polarization and ohmic polarization, and thus improving the electrolysis efficiency and system stability.

[0017] Optionally, the annular flow channel and the guide groove of the liquid outlet are both provided with a pressing groove, and the pole frame area is also provided with a pressing sheet, the upper surface of the pressing sheet is in the same plane as the pole frame area, and the thickness of the pressing sheet is 0.5-5 mm.

[0018] By adopting the above technical solution, the annular flow channel and the liquid outlet guide groove are both provided with a pressing groove, and the upper surface of the pressing sheet and the bipolar plate frame area are in the same plane, thereby achieving the stable fixation and flatness requirements of the pressing sheet, ensuring the uniform distribution of the electrolyte on the bipolar plate, and improving the uniformity and stability of the electrolysis reaction.

[0019] Optionally, sealing grooves are provided on both the inner and outer sides of the electrolyte flow field and the liquid outlet.

[0020] By adopting the above technical solution, the bipolar plate adopts double sealing, and the sealing groove is set to achieve an ideal sealing effect, ensuring the safety and stability of the electrolysis process, reducing electrolyte leakage and system failures caused by poor sealing, and improving the reliability and service life of the system.

[0021] Optionally, the bipolar plate is applicable to an integrated bipolar plate or a bipolar plate with a separate polar frame and a main polar plate.

[0022] By adopting the above technical solution, the water flow entry angle and path are optimized, the water flow is evenly distributed on the surface of the bipolar plate, the uniformity of the electrolysis reaction and the electrolysis efficiency are improved, local overheating or energy loss is reduced, and the stability of the water electrolysis process is ensured.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. The water inlet design of the bipolar plate for a water electrolyzer with an annular water inlet provided by the invention is to optimize the water flow entry angle and path. The annular water inlet design can achieve uniform distribution of water flow on the surface of the bipolar plate, avoiding the flow dead corners and local over-current phenomena that may exist in traditional designs. This uniform water flow distribution improves the uniformity of the electrolysis reaction and ensures that the electrolysis process is carried out with the same efficiency in the entire reaction area, thereby improving the overall electrolysis efficiency; 2. The bipolar plate water inlet design for a water electrolyzer with an annular water inlet provided by the present invention can effectively prevent problems such as local overreaction and overheating, and ensure the long-term stable operation of the water electrolysis system. The flow channel design of the system is simplified, and the complex components that may cause failures are reduced, making the system easier to maintain and operate, thereby further improving the reliability of the system; 3. The bipolar plate water inlet design for a water electrolyzer with a ring-shaped water inlet provided by the present invention is not only suitable for the improvement of existing water electrolysis systems, but can also be easily integrated into new systems of different scales and specifications. It has a simple design structure, a mature manufacturing process, and reduces manufacturing costs, and has good economic benefits and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is a schematic diagram showing the bipolar plate structure of this application.

[0026] Figure 2 This application shows a schematic diagram of the water flow path of the annular water inlet.

[0027] Figure 3 This application shows the tablet pressing groove and tablet pressing schematic diagram.

[0028] Figure 4 This application shows the polarization curve diagram.

[0029] Figure numerals: 101, liquid inlet; 102, outer flow channel of annular flow channel; 103, inner flow channel of annular flow channel; 104, guide groove of annular flow channel; 105, liquid outlet; 106, guide groove of liquid outlet; 107, sealing groove; 201, pressing groove of annular flow channel; 202, pressing groove of liquid outlet guide groove; 203, pressing sheet of annular flow channel; 204, pressing sheet of liquid outlet guide groove. DETAILED DESCRIPTION

[0030] The following is combined with Figure 1 To Attachment Figure 4 This application is described in further detail.

[0031] The embodiment of the present application discloses a bipolar plate for a water electrolyzer having an annular water inlet.

[0032] Comparison Figure 1 , a flat-type integrated bipolar plate is adopted, and an annular flow channel is provided on the outside of the liquid inlet 101, and the annular flow channel is divided into an outer annular flow channel 102 and an inner annular flow channel 103, hereinafter referred to as the inner flow channel and the outer flow channel, wherein the outer flow channel is connected to the liquid inlet 101, and the inner flow channel is evenly distributed with guide grooves connected thereto. After the electrolyte enters from the liquid inlet 101, it first flows to the outer flow channels on the left and right sides respectively, returns through the inner flow channel, and then guides the water flow into the plate reaction area through the guide groove, and then evenly distributes it on the surface of the bipolar plate. The width and depth of the water inlet channel are optimized to ensure that the water flow has an appropriate flow rate and pressure when entering the surface of the bipolar plate, so as to achieve uniform distribution.

[0033] The annular flow channel is located in the pole frame area, and the arc is within the range of 180°~300°. The annular flow channel is symmetrically distributed in the center. The liquid inlet 101 is arranged at the intersection of the vertical center line of the outer flow channel and the annular center line. The annular flow channel of the bipolar plate allows the electrolyte to be evenly distributed in the reaction area of ​​the pole plate, which improves the uniformity and electrolysis efficiency of the electrolysis reaction and avoids the phenomenon of local overcurrent or retention. The annular flow channel is symmetrically distributed about the center, which further ensures the uniform distribution of the electrolyte and enhances the consistency of the reaction. The design of the inner and outer flow channels allows the electrolyte to flow into the reaction area of ​​the pole plate from multiple directions, increasing the reaction area and improving the reaction rate. The liquid inlet 101 is arranged at the intersection of the vertical center line of the outer flow channel and the annular center line and is connected to the outer flow channel, which optimizes the inlet position of the electrolyte, reduces the turbulence of the liquid, and enables the electrolyte to smoothly enter the reaction area, thereby improving the stability and efficiency of the reaction. The liquid outlet 105 is symmetrical along the opposite sides of the plane centerline of the liquid inlet 101, and the angle between the liquid outlet 105 and the plane centerline of the liquid inlet 101 is in the range of 10°~20°. The liquid outlet 105 is symmetrically arranged on the opposite sides of the plane centerline of the liquid inlet 101, so that a symmetrical flow path can be formed when the electrolyte flows out, effectively avoiding the local liquid accumulation phenomenon, and ensuring the uniform distribution of the electrolyte in the entire plate reaction area. At the same time, the angle between the liquid outlet 105 and the plane centerline of the liquid inlet 101 is in the range of 10~20, ensuring that the direction of electrolyte outflow forms a certain angle with the liquid inlet direction, which helps to improve the flow efficiency of the electrolyte, reduce dead zones, and further improve the uniformity and efficiency of the electrolytic reaction.

[0034] The guide groove is connected to the inner flow channel of the annular flow channel, and the guide groove is evenly distributed at 5~20° along the center of the bipolar plate. The guide groove allows the electrolyte to flow evenly from the annular flow channel to the plate reaction area, improving the uniformity and efficiency of the electrolytic reaction. The guide groove is connected to the inner flow channel of the annular flow channel and is evenly distributed at 5~20° along the center of the plate, ensuring the smooth flow path of the electrolyte, reducing the problems of local overheating and bubble accumulation, and improving the overall reaction performance.

[0035] The liquid outlet 105 is provided with a guide groove connected to the electrode plate reaction zone, and the guide grooves are symmetrically distributed along the axis of the liquid outlet 105. The liquid outlet 105 is provided with a guide groove connected to the electrode plate reaction zone, so that the electrolyte and the gas generated by electrochemistry can enter the liquid outlet 105 more smoothly from the electrode plate reaction zone through the guide groove, thereby improving the discharge efficiency of the electrolysis product and ensuring the stability and continuity of the electrolysis reaction. The guide grooves are symmetrically distributed about the axis of the liquid outlet 105, ensuring the uniform discharge of the electrolyte and the gas, reducing the local accumulation phenomenon, and improving the overall performance of the electrolytic cell.

[0036] See also Figure 3As shown, the guide grooves of the annular flow channel and the outlet 105 are both provided with a pressing groove, and the pole frame area is also provided with a pressing sheet, the upper surface of the pressing sheet is in the same plane with the pole frame area, and the thickness of the pressing sheet is 0.5~5mm. The annular structure flow field and the guide groove of the outlet 105 are both provided with a pressing groove, namely the groove 201 of the annular flow channel pressing sheet 203 and the pressing groove of the guide groove of the outlet 105. The pressing sheet is provided correspondingly, namely the annular flow channel pressing sheet 203 and the guiding pressing sheet of the outlet 105, so that the pressing sheet can be stably installed on the bipolar plate, ensuring that the pressing sheet and the pole frame area of ​​the bipolar plate are in the same plane, avoiding the problem of uneven flow field caused by the protrusion or sinking of the pressing sheet, and improving the uniformity and stability of the electrolyte flow. The thickness of the pressing sheet is between 0.5~5mm, which not only ensures the mechanical strength of the pressing sheet, but also effectively reduces the influence of the pressing sheet on the electrolyte flow, and improves the electrolysis efficiency.

[0037] Sealing grooves 107 are provided on both the inner and outer sides of the electrolyte flow field and the liquid outlet 105. Sealing grooves 107 are provided on both the inner and outer sides of the annular structure flow field and the liquid outlet 105 of the bipolar plate, which can effectively prevent electrolyte leakage and improve the safety of the system. At the same time, the double sealing design ensures that the electrolytic cell can still maintain good sealing performance when operating at high current density, thereby improving electrolysis efficiency and stability.

[0038] The bipolar plate is suitable for integrated bipolar plates and bipolar plates separated from the pole frame and the main pole plate. It optimizes the water flow entry angle and path, realizes the uniform distribution of water flow on the surface of the bipolar plate, improves the uniformity of the electrolysis reaction and the electrolysis efficiency, reduces local overheating or energy loss, and ensures the stability of the water electrolysis process; the bipolar plate is suitable for alkaline water electrolyzers, especially alkaline water electrolyzers operating at high current density, reduces the intensity and resistance of local reactions, reduces energy loss in the electrolysis process, prevents local overheating, and ensures the long-term stable operation of the system.

[0039] See also Figure 2 As shown in the figure, a schematic diagram of the water flow path is shown. Since the water inlet surrounds the central area, the water flow expands radially outward, ensuring the uniformity of reaction conditions on the entire bipolar plate surface. This uniform water flow distribution not only improves the electrolysis efficiency, but also reduces local reaction overheating and energy loss, ensuring the stability and efficiency of the water electrolysis process.

[0040] Figure 2 The water flow path in the figure shows that the water flow expands outward from the central annular water inlet in a radial manner, and then evenly covers the entire bipolar plate surface. By reasonably designing the width and depth of the flow channel, the water flow can maintain an appropriate speed and pressure, avoiding turbulence caused by excessively high flow velocity or insufficient reaction caused by too low flow velocity.

[0041] In order to ensure that the water flow pressure in each water inlet channel is consistent, a pressure equalization device can be introduced in the implementation mode, which makes the pressure on the bipolar plate more uniform and ensures that the water flow at the annular water inlet enters the bipolar plate evenly. The pressure equalization device can be adjusted according to actual needs to adapt to the optimal water flow distribution under different operating conditions.

[0042] The conventional single-side water inlet bipolar plate and the annular bipolar plate water inlet were installed in the same electrolyzer for performance testing. Figure 4 As shown in the figure, the current density was measured from 100 A m at a test temperature of 80 °C. -2 to 10000 A m -2 The voltage changes within the range, when the current density is less than 2000 A m -2 When the current density increases from 2000 A m -2 Up to 10000 A m -2 When the current density is 10000 A m -2 When the average cell voltage of the electrolyzer containing the annular bipolar plate water inlet is 1.937V, it is 41mV lower than that of the conventional single-side water inlet bipolar plate (1.978V). This indicates that the annular bipolar plate water inlet provided by the present invention can effectively improve the water electrolysis efficiency and reduce energy consumption.

[0043] The implementation principle of the bipolar plate for a water electrolysis cell with an annular water inlet in the embodiment of the present application is as follows: the annular structure flow field surrounding the center of the bipolar plate enables the electrolyte to be evenly distributed to various areas of the plate reaction zone, avoiding the existence of flow dead corners and local overcurrent phenomena, ensuring that the electrolysis process is carried out with the same efficiency in the entire reaction area, and significantly improving the uniformity and efficiency of the electrolysis reaction; the setting of the guide groove and the sealing groove 107 ensures the patency and sealing effect of the flow path of the electrolyte, avoids local overheating and insufficient reaction, ensures the long-term stable operation of the electrolysis system, simplifies the flow channel design of the system, reduces complex components that may cause failures, makes the system easier to maintain and operate, and improves system reliability; it is suitable for the improvement of different water electrolysis systems and can be integrated into new systems of different specifications and scales. It has a simple structure, a more mature manufacturing process, and reduces manufacturing costs.

[0044] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second", "third" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "One" or "one" and similar words do not indicate a quantitative limit, but indicate the existence of at least one. "Include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0045] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A bipolar plate for a water electrolyzer with an annular water inlet, characterized in that: The invention comprises a pole frame area and a pole plate reaction area, wherein an electrolyte flow field, a guide groove, a liquid inlet (101) and a liquid outlet (105) are arranged in the pole frame area, wherein the electrolyte flow field is an annular structure surrounding the center of the bipolar plate, wherein the annular structure enables water to flow evenly through the guide groove into each area of ​​the pole plate reaction area, wherein an annular flow channel is arranged outside the liquid inlet (101), wherein the annular flow channel is divided into an inner flow channel and an outer flow channel, wherein the outer flow channel is connected to the liquid inlet (101), the inner flow channel is evenly distributed, and the inner flow channel is connected to the guide groove.

2. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: The annular flow channel is located in the pole frame area, with an arc in the range of 180° to 300°. The annular flow channel is centrally symmetrically distributed, and the liquid inlet (101) is arranged at the intersection of the vertical center line of the outer flow channel and the annular center line.

3. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: The liquid outlet (105) is symmetrical along the opposite sides of the plane center line of the liquid inlet (101), and the angle between the liquid outlet (105) and the plane center line of the liquid inlet (101) is in the range of 10° to 20°.

4. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: The guide grooves are connected to the inner flow channel of the annular flow channel, and the guide grooves are evenly distributed at 5-20 degrees along the center of the bipolar plate.

5. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: The liquid outlet (105) is provided with a guide groove connected to the electrode plate reaction area, and the guide groove is symmetrically distributed along the axis of the liquid outlet (105).

6. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: The guide grooves of the annular flow channel and the liquid outlet (105) are both provided with pressing grooves, and the pole frame area is also provided with a pressing sheet. The upper surface of the pressing sheet is in the same plane as the pole frame area, and the thickness of the pressing sheet is 0.5-5 mm.

7. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: Sealing grooves (107) are provided on both the inner and outer sides of the electrolyte flow field and the liquid outlet (105).

8. The bipolar plate for a water electrolyzer with an annular water inlet according to claim 1, characterized in that: The bipolar plate is suitable for an integrated bipolar plate and a bipolar plate with a separate pole frame and main pole plate.

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