AEM electrolytic bath

Abstract

The invention relates to an AEM electrolytic bath. The current density and the heat exchange capacity of the electrolytic bath are improved. Liquid on the anode side of each single section of the electrolytic cell can uniformly and quickly flow on the surface of the anion exchange membrane, oxygen generated on the anode side can be quickly and effectively discharged out of the electrolytic cell, and hydrogen generated on the cathode side and water permeated from the anion exchange membrane can be timely and efficiently discharged out of the electrolytic cell; certain pressure is provided for the cathode catalyst layer and the anode catalyst layer, so that the catalyst layers are uniformly stressed and attached to the two sides of the anion exchange membrane. In a comparison test of electrolysis with an active area of 300cm < 2 >, under the same conditions of 2V voltage and temperature of 60 DEG C, the current value of the electrolytic bath of a cutting machining flow field on a metal pole plate is 218A, the current value of the electrolytic bath of a spongy foam metal flow field with a groove-shaped flow channel is 289A, and the efficiency is improved by 32.56%. And under other working conditions, the test current is also improved by 20%-32%.

Description

Technical Field

[0001] The present invention relates to a method for optimizing and improving the uniformity of the liquid and gas flow field inside an AEM electrolyzer, thereby improving the current density and heat exchange capacity of the electrolyzer. In order to make the liquid on the anode side of each single section of the electrolyzer uniformly and quickly flow to the surface of the anion exchange membrane, the oxygen generated on the anode side can be quickly and effectively discharged from the electrolyzer, and the hydrogen generated on the cathode side and the water permeated from the anion exchange membrane can be timely and efficiently discharged from the electrolyzer; and to provide a certain pressure for the cathode catalyst layer and the anode catalyst layer so that the catalyst layer is evenly attached to the two sides of the anion exchange membrane. Background Art

[0002] Anion exchange membrane (AEM) water electrolysis is one of the most promising water electrolysis systems and has great market competitiveness. Compared with traditional alkaline water electrolysis, AEM electrolyzers can achieve low ohmic resistance and high gas purity; compared with proton exchange membrane (PEM) water electrolysis, AEM electrolyzers allow the use of highly active transition metal materials as electrochemical catalysts and substrates, with lower overall costs.

[0003] However, a serious problem has been discovered in current industrial practice. As the active area of ​​a single-section electrode continues to expand, the alkaline water used as a raw material becomes unevenly distributed in the electrode. This unevenness prevents the catalyst in some areas from fully participating in the reaction process, which in turn affects the performance of the current density. In addition, when the alkaline liquid flows into the tank, it will also take away the heat energy generated by the electrolysis of water in areas that do not participate in the reaction, and the heat will be adjusted secondary to maintain the temperature balance in the tank. In extreme cases, if the alkaline water flow rate is not accurately controlled, it may cause the local temperature to be too high, triggering a burnout of the electrolytic cell.

[0004] In view of this, the present invention aims to ensure the uniformity of the flow field by optimizing the structure of the electrode and improving the flow mode of alkaline water, thereby avoiding the risk of damage to the electrolyzer due to local overheating or other adverse conditions. By accurately controlling the flow rate and flow rate of alkaline water, the heat loss can be effectively reduced, and the temperature of the electrode surface can be kept stable, ultimately improving the performance and efficiency of the electrolyzer. This can greatly improve the phenomenon of poor uniformity of liquid and gas distribution in the cell body, reduce production costs, improve the hydrogen production efficiency of the electrolyzer, and at the same time improve the reliability and economy of the entire electrolyzer system. Summary of the invention

[0005] The present invention relates to a method for optimizing and improving the uniformity of liquid and gas flow fields inside an AEM electrolytic cell, and the technical solution adopted is:

[0006] An AEM electrolytic cell, which is a single-section AEM electrolytic cell or a multi-section AEM electrolytic cell stacked in sequence,

[0007] The two ends of a single-section AEM electrolyzer are polar plates, and between the two polar plates is a group of hollow annular cathode electrode frames, anion exchange membranes, and hollow annular anode electrode frames stacked in sequence; the two ends of a multi-section AEM electrolyzer are polar plates, and between the two polar plates are multiple groups of hollow annular cathode electrode frames, anion exchange membranes, and hollow annular anode electrode frames stacked in sequence, with adjacent groups separated by bipolar plates; the cathode is placed in the middle cavity of the hollow annular cathode electrode frame, and the anode is placed in the middle cavity of the hollow annular anode electrode frame;

[0008] A flat foam metal is arranged in the middle cavity of the hollow annular cathode electrode frame, and the flat foam metal is located between the cathode and the electrode plate or between the cathode and the bipolar plate. After being assembled into an AEM electrolytic cell, one side surface of the flat foam metal is bonded to the cathode, and the other side surface is bonded to the electrode plate or the bipolar plate.

[0009] A flat foam metal is arranged in the middle cavity of the hollow annular anode electrode frame. The flat foam metal is located between the anode and the polar plate or between the anode and the bipolar plate. After being assembled into an AEM electrolytic cell, one side surface of the flat foam metal is bonded to the anode, and the other side surface is bonded to the polar plate or the bipolar plate.

[0010] The cathode cavity is formed by the polar plate or bipolar plate on one side of the hollow annular cathode electrode frame, the anion exchange membrane on the other side, and the middle cavity surrounded by the hollow annular cathode electrode frame, and the area in the cathode cavity except the cathode is filled with sponge-like foam metal material;

[0011] The anode cavity is composed of the polar plate or bipolar plate on one side of the hollow annular anode electrode frame, the anion exchange membrane on the other side and the middle cavity surrounded by the hollow annular anode electrode frame. The area in the anode cavity except the cathode is filled with sponge-like foam metal material.

[0012] The porosity of the sponge-like foamed metal material is 72-96%.

[0013] A flow field formed by a groove flow channel is provided on one side surface of the flat foam metal close to the electrode plate or bipolar plate; the flow field on one side surface of the sponge-like foam metal sheet in the cathode electrode frame is the cathode flow field, and the flow field on one side surface of the sponge-like foam metal sheet in the anode electrode frame is the anode flow field.

[0014] The foam metal material is a flat plate structure. In order to ensure better flow of liquid on the anode side and uniform distribution of liquid water, a groove flow channel is added to the side of the sponge-like foam metal material with a flat plate structure away from the electrode (cathode or anode) to form a flow field; in this way, the sponge-like foam metal material flow channel forms a spatial network flow channel structure with the groove flow channel as the main flow channel and the three-dimensional microporous channel as the branch flow channel.

[0015] The foam metal is one or more of foam nickel, foam titanium and foam iron;

[0016] The groove width is 1 mm to 5 mm, and the groove depth is 20% to 85% of the thickness of the sponge-like foam metal material;

[0017] Groove flow channel refers to the groove on the sponge-like foam metal, and its cross-sectional shape perpendicular to the fluid flow direction includes but is limited to one or more of rectangular, trapezoidal, semicircular, elliptical and other irregular shapes;

[0018] The axial shape of the flow channel along the fluid flow direction includes, but is not limited to, one or more of the following curve shapes: straight line, broken line, S-curve, circle, sine, normal distribution, etc.

[0019] The groove flow channel is on the side of the sponge-like foam metal close to the polar plate or bipolar plate;

[0020] Flow channel distribution: on the sponge-like foam metal flow field, including but not limited to one or more of overall distribution, partial distribution, uniform distribution, and non-uniform distribution;

[0021] The flow channels include but are not limited to one or more of the following: intersections, mergers, branches, point-like isolation points, etc.;

[0022] The flow channel includes but is not limited to a single one or multiple ones, preferably two or more parallel flow fields.

[0023] The surface of the electrode plate close to the foam metal or the surfaces of the two sides of the bipolar plate are both flat plate structures, that is, there is no flow field on them but a smooth plane;

[0024] A cathode distribution channel is provided on the upper side and / or lower side of the surface of one side of the annular cathode electrode frame close to the electrode plate or bipolar plate, one end or both ends of which are respectively connected to the cathode port end (outlet) of the cathode flow field and the cathode gas-liquid outlet channel of the AEM electrolyzer; there are one or two cathode ports, both of which are mainly used for hydrogen outlet and liquid discharge (outlet), and also have functions such as nitrogen purge (one inlet and one outlet for purge gas when there are two ports).

[0025] Anode distribution channels are provided on the upper and lower sides of one side surface of the annular anode electrode frame close to the electrode plate or bipolar plate, and the two ends thereof are respectively connected with the inlet and outlet ends of the anode flow field and the anode inlet and outlet channels of the AEM electrolytic cell; the two ends of the anode distribution channel on one side are respectively connected with the inlet end of the anode flow field and the anode inlet channel of the AEM electrolytic cell, and the two ends of the anode distribution channel on the other side are respectively connected with the outlet end of the anode flow field and the anode outlet channel of the AEM electrolytic cell.

[0026] The cathode includes a cathode catalyst layer, or a cathode catalyst substrate and a cathode catalyst layer, the cathode catalyst layer is attached or coated on one side of the cathode catalyst substrate or the cathode side of the anion exchange membrane, and the cathode catalyst layer is arranged facing the anion exchange membrane side;

[0027] The anode includes an anode catalyst layer, or includes an anode catalyst substrate and an anode catalyst layer, the anode catalyst layer is attached or coated on one side surface of the anode catalyst substrate or the anode side of the cation exchange membrane, and the anode catalyst layer faces and fits the anion exchange membrane, and the opposite side of the anode catalyst substrate faces and fits the foam metal (as a diffusion layer of the electrode);

[0028] The cathode catalytic substrate and the anode catalytic substrate are respectively sheet structures with micropores, and can be one or more of mesh carbon paper, carbon cloth, metal wire mesh, and metal felt.

[0029] The cathode and anode flow fields of the electrolyzer are composed of sponge-like foam metal materials. In each section of the electrolyzer, the anion exchange membrane divides the section into two parts: the cathode chamber and the anode chamber. In addition to using a mesh carrier with a catalyst layer and them, the cathode chamber and the anode chamber are filled with a flow field of sponge-like foam metal materials. The three-dimensional mesh channel of the sponge-like foam metal material flow field in the anode chamber plays a role in evenly distributing the water entering the anode chamber from the anode port on one side close to the surface of the electrode plate or bipolar plate to the surface of the anode side of the anion exchange membrane, and can provide the three-dimensional channel of the sponge-like foam metal material flow field in the anode chamber to discharge the oxygen and excess water from the anode port on the other side close to the surface of the electrode plate or bipolar plate; the three-dimensional mesh structure of the sponge-like foam metal material flow field in the cathode chamber provides the hydrogen generated on the cathode side of the anion exchange membrane and a small amount of water permeated from the membrane to discharge the electrolyzer from the cathode port.

[0030] The flow field of the sponge-like foam metal material is generally a flat plate structure. In order to better flow the liquid on the anode side and distribute the liquid evenly, the present invention adds some groove flow channels on the side of the sponge-like foam metal material with a flat structure away from the catalyst layer. In this way, the sponge-like foam metal material flow channel forms a spatial mesh flow channel structure with the groove flow channel as the main flow channel and the three-dimensional microporous channel as the branch flow channel. The liquid entering the anode cavity from the anode port can be quickly distributed to the entire anode flow field through the groove flow channel of the anode flow field. At the same time, through the three-dimensional microporous channel of the anode flow field, the liquid is secondary distributed and can reach all parts of the anode catalyst layer more evenly. The oxygen generated in the anode catalyst layer can enter the groove flow channel of the anode flow field through the three-dimensional micropores, and then be discharged to the anode port and then to the outside of the electrolyzer with a smaller flow resistance. The hydrogen generated on the cathode side and the leaked liquid also enter the groove flow channel of the cathode flow field through the three-dimensional microporous channel of the cathode flow field, and are discharged to the cathode port with a smaller flow resistance. After testing the voids of different sponge-like foam metal materials, the void ratio of 72 to 96% is the best. The groove width is 1mm to 5mm, and the groove depth is 20% to 85% of the thickness of the sponge-like foam metal material. According to actual tests on electrolytic cells, the current density can be increased by 20% to 32.6% after adding the grooved flow channel.

[0031] As a sponge-like foam metal material, some groove-like flow channels are made on it. The liquid and gas in the flow channel mainly flow through the flow channel and are quickly distributed to various areas of the diffusion layer. At the same time, they will penetrate through the micropores of the sponge-like foam metal material and interact with the anion exchange membrane.

[0032] At the same time, the sponge-like foam metal material flow field plays a supporting role within the subsection, so that the cathode catalyst layer and the anode catalyst layer can fit tightly with the anion exchange membrane under different working conditions, which helps the anions generated on the anode catalyst layer to be efficiently transferred to the surface of the cathode catalyst layer through the anion exchange membrane, thereby efficiently generating oxygen.

[0033] Relying on the assembly force of the battery stack, the flow channel and the electrode plate form a complete flow channel wall, which can effectively ensure the flow of gas and liquid in the flow channel.

[0034] The flow channel refers to the groove on the sponge-like foam metal material, and its cross-sectional shape includes but is not limited to other irregular shapes such as rectangle, circle, trapezoid, semicircle, ellipse, etc.

[0035] The longitudinal shape of the flow channel includes, but is not limited to, straight lines, broken lines, S-curves, circles, sinusoidal shapes, normal distribution and other curved shapes.

[0036] Flow channel distribution: on the diffusion layer of the sponge-like foam metal material, including but not limited to overall distribution, partial distribution, uniform distribution, and non-uniform distribution.

[0037] The flow channels include but are not limited to intersections, mergers, branches, point-like isolation points, etc.

[0038] The flow channels include but are not limited to a single channel, multiple channels, and combinations thereof.

[0039] According to the above method, no flow channel needs to be processed on the electrode plate. Relying on the screw locking force of the outer end plate of the stack, the groove flow channel of the sponge-like foam metal flow field and the electrode plate form a complete flow channel. Because the groove flow channel is on one side of the sponge-like foam metal flow field, rather than opening the groove flow channel on the electrode plate. This structure shortens the transmission distance of liquid and gas. Reduces the flow resistance of gas and liquid in the flow channel. The cathode frame, anode frame, anion exchange membrane and electrode plate are locked together by the screw locking force of the outer end plate to form a cathode cavity and an anode cavity respectively. Each cavity contains a sheet catalyst substrate with a catalytic layer and a sponge-like foam metal flow field. After assembly, the flow channel surface of the sponge-like foam metal flow field is tightly fitted with the electrode plate; the non-flow channel surface of the diffusion layer is fitted with the non-catalytic layer of the catalyst carrier; the catalytic layer of the catalyst substrate is tightly fitted with the anion exchange membrane.

[0040] Sponge-like foam metal has a rich three-dimensional pipeline structure and has excellent functions for transporting liquids and gases. Compared with the general cutting and processing flow channels or stamping flow fields on metal plates, the hydrogen production efficiency of the sponge-like foam metal flow field with grooved flow channels has been greatly improved and the processing cost has been greatly reduced. Adding grooved flow channels on the side of the sponge-like foam metal away from the anion exchange membrane can further improve the uniformity of liquid and gas distribution in the cell body. A comparative test was conducted on a certain electrolyzer. The comparative test flow field uses a sponge-like foam metal with a flow channel and a bipolar plate using a metal cutting electrolyzer. Except for the above differences, other components are the same. The test conditions also use a DC voltage of 1.6 to 2V, a temperature of 60°C, and a water inlet of 10L / min. Among them, at a voltage of 2V, the current density of the electrolyzer with a cutting flow field on the metal plate is 0.76A / cm 2 , while the current value of the electrolytic cell with sponge-like foam metal flow field is 0.98A / cm 2 , the efficiency is increased by 29%. Under other working conditions, the test current is also increased by 22% to 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0042] Figure 1 : Schematic diagram of the structure of the battery stack (with the first plate on the left removed) in which multiple single cells are stacked together in the present invention.

[0043] Figure 2 : Schematic diagram of the explosion of a single-section electrolytic cell in the present invention.

[0044] In the figure: 1, electrode plate; 2, cathode electrode frame; 2.1, cathode port (common features with 1 to 8); 3, cathode catalytic substrate; 3.1, cathode catalytic layer; 4, anode catalytic substrate; 4.1, cathode catalytic layer; 5, anode electrode frame; 5.1, anode port (common features with 1 to 8); 6, anode flow field; 6.1, anode flow field groove flow channel; 7, anion exchange membrane; 8, cathode flow field; 8.1, cathode flow field groove flow channel; 9, anode cavity (composed of the space surrounded by 5 / 1 / 7, 4 / 6 is placed therein) 10, cathode cavity (composed of the space surrounded by 2 / 1 / 7, 3 / 8 is placed therein);

[0045] Figure 3 : Data comparison of the test results of the two flow field structures at 60℃, water flow rate 10L / min and voltage 1.6V~2.0V. DETAILED DESCRIPTION

[0046] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0047] Example 1

[0048] See also Figure 1 as well as Figure 2 , as shown in the figure, the specific structure is:

[0049] An AEM electrolytic cell, comprising 20 AEM electrolytic cells stacked in sequence,

[0050] The AEM electrolyzer comprises a hollow annular cathode electrode frame, an anion exchange membrane, and a hollow annular anode electrode frame, which are stacked in sequence between two polar plates (end plates) separated by bipolar plates; a cathode is placed in the middle cavity of the hollow annular cathode electrode frame, and an anode is placed in the middle cavity of the hollow annular anode electrode frame.

[0051] A flat foam metal is arranged in the middle cavity of the hollow annular cathode electrode frame, and the flat foam metal is located between the cathode and the polar plate or bipolar plate. After being assembled into an AEM electrolytic cell, one side surface of the sheet foam metal is bonded to the cathode, and the other side surface is bonded to the polar plate or bipolar plate.

[0052] A flat foam metal is arranged in the middle cavity of the hollow annular anode electrode frame, and is located between the anode and the polar plate or bipolar plate. After being assembled into an AEM electrolytic cell, one side surface of the sheet foam metal is bonded to the anode, and the other side surface is bonded to the polar plate or bipolar plate.

[0053] The cathode cavity is formed by the polar plate or bipolar plate on one side of the electrode frame, the anion exchange membrane on the other side and the middle cavity of the hollow annular cathode electrode frame surrounded by the electrode frame, and the area in the cathode cavity except the cathode is filled with sponge-like foam metal material;

[0054] The anode cavity is formed by the polar plate or bipolar plate on one side of the electrode frame, the anion exchange membrane on the other side and the middle cavity of the hollow ring-shaped anode electrode frame surrounded by the electrode frame. The area in the anode cavity except the cathode is filled with sponge-like foam metal material.

[0055] The porosity of the sponge-like foamed metal material is 85%.

[0056] A flow field formed by a groove flow channel is provided on the surface of one side of the flat foam metal close to the electrode plate or bipolar plate; the flow field on the surface of one side of the sponge-like foam metal sheet in the cathode electrode frame is the cathode flow field, and the flow field on the surface of one side of the sponge-like foam metal sheet in the anode electrode frame is the anode flow field.

[0057] The foam metal material has a flat structure. In order to ensure better liquid flow on the anode side and uniform distribution of liquid water, some groove channels are added to the side of the sponge-like foam metal material with a flat structure away from the electrode (cathode or anode) to form a flow field. In this way, the sponge-like foam metal material flow channel forms a spatial network flow channel structure with the groove flow channel as the main flow channel and the three-dimensional microporous channel as the branch flow channel.

[0058] The groove width is 3 mm, and the groove depth is 50% of the thickness of the sponge-like foam metal material;

[0059] The groove flow channel refers to the groove on the sponge-like foam metal, whose cross-sectional shape perpendicular to the fluid flow direction is a rectangle, and the axial shape of the flow channel along the fluid flow direction is a straight line.

[0060] The groove flow channel is on the side of the sponge-like foam metal close to the polar plate or bipolar plate;

[0061] Flow channel distribution: evenly distributed on the sponge-like foam metal flow field; more than two parallel flow fields.

[0062] The surface of the electrode plate close to the foam metal or the surfaces of the two sides of the bipolar plate are both flat plate structures, that is, there is no flow field on them but a smooth plane;

[0063] Cathode distribution channels are provided on two opposite sides of the surface of one side of the annular cathode electrode frame close to the electrode plate or bipolar plate, and the two ends thereof are respectively connected with the cathode port end (outlet) of the cathode flow field and the cathode gas-liquid outlet channel of the AEM electrolyzer; there are two cathode ports, both of which are mainly used for hydrogen gas and liquid discharge (outlet), and also have functions such as nitrogen purge (two ports, one inlet and one outlet for purge gas).

[0064] Anode distribution channels are provided on two opposite sides of the surface of one side of the annular anode electrode frame close to the electrode plate or bipolar plate, and the two ends thereof are respectively connected with the inlet and outlet ends of the anode flow field and the anode inlet and outlet channels of the AEM electrolytic cell; the two ends of the anode distribution channel on one side are respectively connected with the inlet end of the anode flow field and the anode inlet channel of the AEM electrolytic cell, and the two ends of the anode distribution channel on the other side are respectively connected with the outlet end of the anode flow field and the anode outlet channel of the AEM electrolytic cell.

[0065] Figure 1 It consists of 20 Figure 2 The single sections are stacked. Then they are fastened with bolts through the outer end plate. The end plate is provided with corresponding cathode ports and anode ports, and the edges of the cathode electrode frame, anion exchange membrane, and anode electrode frame are also provided with through holes as cathode ports and anode ports, respectively, to form the anode liquid inlet and outlet flow channel and cathode gas-liquid outlet flow channel of the AEM electrolyzer, for liquid in and out and gas out of the electrolyzer.

[0066] The foam metal is foam nickel;

[0067] The middle layer of a single section is an anion exchange membrane (Shanghai Hydrogen Luan Technology Co., Ltd., PHOENIX-30) that has a selective permeability to anions. The two sides of the anion exchange membrane are coated or covered with iron-based, nickel-based, chromium-based cathode catalysts (Shanghai Hydrogen Luan Technology Co., Ltd., PHOENIX-Ca-5Ni / C) and anode catalysts. (Shanghai Hydrogen Luan Technology Co., Ltd., PHOENIX-An-30Ni2P). The side covering the cathode catalyst is called the cathode, and the opposite side is called the anode. The catalyst layer is bonded with a sponge-like foam metal with a flow channel. The sponge-like foam metal with a flow channel is surrounded by an electrode frame, and there is a channel on the anode electrode frame. The liquid pumped into the electrolytic cell distributes the liquid to the channel on the anode electrode frame of each single section through the anode port, and then enters the anode cavity through the channel on the anode electrode frame. The sponge-like foam metal with a flow channel in the anode cavity distributes the inflowing liquid evenly in the anode area, and discharges the excess liquid that does not participate in the electrolysis reaction and the oxygen generated by the reaction through the channel on the anode electrode frame at the other end and the anode port out of the electrolytic cell. As anions permeate through the anion exchange membrane, hydrogen is generated on the cathode side. The hydrogen and the liquid that permeates through the anion exchange membrane pass through the cathode band flow channel sponge-like foam metal, through the cathode electrode frame channel, and the cathode port to be discharged from the electrolyzer. Each single section is separated by a bipolar plate.

[0068] Specific operating parameters: 60°C, water flow rate 10L / min, current density of two flow field structures (Example 1 and Comparative Example) at voltages of 1.6V to 2.0V (1.6V, 1.7V, 1.8V, 1.9V, 2.0V respectively), Figure 3 As shown;

[0069] The effective area of ​​each single-section electrolytic cell electrode in Example 1 and Comparative Example is 100 cm2 (Length and width 10cm*10cm)

[0070] Comparative Example Electrolyzer Structure: The cathode cavity and anode cavity of the electrolyzer do not have sponge-like foam metal as a diffusion layer, and are hollow structures, and the space is replaced by a boss with a flow channel structure at the corresponding position of the electrode plate / bipolar plate. The size and direction of the flow channel are the same as those in Example 1. The diffusion method is mainly through the flow channel of the electrode plate / bipolar plate. (This structure is similar to the common fuel cell bipolar plate structure)

[0071] Example 2

[0072] See also Figure 1 as well as Figure 2 As shown, the structural composition is the same as that of Example 1, except that in the electrolytic cell, the cathode port or anode port of Example 1, which are respectively placed at two vertically opposite sides of the square flow field, are moved to the same side of the square flow field.

[0073] Example 3

[0074] See also Figure 1 as well as Figure 2 As shown, the structural composition is the same as that of Example 1, except that the square sponge-shaped foam metal flow field (flow channel, cross-sectional shape perpendicular to the fluid flow direction) in Example 1 is changed to a semicircular shape.

Claims

1. An AEM electrolytic cell, comprising one or more AEM electrolytic cells stacked in sequence, A single-section AEM electrolyzer comprises a stacked electrode plate, a hollow annular cathode electrode frame, an anion exchange membrane, a hollow annular anode electrode frame, and an electrode plate; an AEM electrolyzer having two or more sections comprises a stacked hollow annular cathode electrode frame, an anion exchange membrane, and a hollow annular anode electrode frame separated by bipolar plates between the two electrodes; a cathode is placed in the middle cavity of the hollow annular cathode electrode frame, and an anode is placed in the middle cavity of the hollow annular anode electrode frame, characterized in that: A flat foam metal is arranged in the middle cavity of the hollow annular cathode electrode frame, and the flat foam metal is located between the cathode and the polar plate or bipolar plate. After being assembled into an AEM electrolytic cell, one side surface of the sheet foam metal is bonded to the cathode, and the other side surface is bonded to the polar plate or bipolar plate. A flat foam metal is arranged in the middle cavity of the hollow annular anode electrode frame, and is located between the anode and the polar plate or bipolar plate. After being assembled into an AEM electrolytic cell, one side surface of the sheet foam metal is bonded to the anode, and the other side surface is bonded to the polar plate or bipolar plate.

2. The AEM electrolyzer according to claim 1, characterized in that: The cathode cavity is formed by the polar plate or bipolar plate on one side of the electrode frame, the anion exchange membrane on the other side and the middle cavity of the hollow annular cathode electrode frame surrounded by the electrode frame, and the area in the cathode cavity except the cathode is filled with sponge-like foam metal material; The anode cavity is formed by the polar plate or bipolar plate on one side of the electrode frame, the anion exchange membrane on the other side and the middle cavity of the hollow ring-shaped anode electrode frame surrounded by the electrode frame. The area in the anode cavity except the cathode is filled with sponge-like foam metal material.

3. The AEM electrolyzer according to claim 1 or 2, characterized in that: The porosity of the sponge-like foamed metal material is 72-96%.

4. The AEM electrolyzer according to claim 1 or 2, characterized in that: A flow field formed by a groove flow channel is provided on the surface of one side of the flat foam metal close to the electrode plate or bipolar plate; the flow field on the surface of one side of the sponge-like foam metal sheet in the cathode electrode frame is the cathode flow field, and the flow field on the surface of one side of the sponge-like foam metal sheet in the anode electrode frame is the anode flow field.

5. The AEM electrolyzer according to claim 4, characterized in that: The foam metal material has a flat structure. In order to ensure better liquid flow on the anode side and uniform distribution of liquid water, some groove channels are added to the side of the sponge-like foam metal material with a flat structure away from the electrode (cathode or anode) to form a flow field. In this way, the sponge-like foam metal material flow channel forms a spatial network flow channel structure with the groove flow channel as the main flow channel and the three-dimensional microporous channel as the branch flow channel.

6. The AEM electrolyzer according to claim 3 or 4, characterized in that: The foam metal is one or more of foam nickel, foam titanium and foam iron; The groove width is 1 mm to 5 mm, and the groove depth is 20% to 85% of the thickness of the sponge-like foam metal material; Groove flow channel refers to the groove on the sponge-like foam metal, and its cross-sectional shape perpendicular to the fluid flow direction includes but is limited to one or more of rectangular, trapezoidal, semicircular, elliptical and other irregular shapes; The axial shape of the flow channel along the fluid flow direction includes, but is not limited to, one or more of the following curve shapes: straight line, broken line, S-curve, circle, sine, normal distribution, etc.

7. The AEM electrolyzer according to claim 6, characterized in that: The groove flow channel is on the side of the sponge-like foam metal close to the polar plate or bipolar plate; Flow channel distribution: on the sponge-like foam metal flow field, including but not limited to one or more of overall distribution, partial distribution, uniform distribution, and non-uniform distribution; The flow channels include but are not limited to one or more of the following: intersections, mergers, branches, point-like isolation points, etc.; The flow channel includes but is not limited to a single one or multiple ones, preferably two or more parallel flow fields.

8. The AEM electrolyzer according to any one of claims 4 to 7, characterized in that: The surface of the electrode plate close to the foam metal or the surfaces of the two sides of the bipolar plate are both flat plate structures, that is, there is no flow field on them but a smooth plane; A cathode distribution channel is provided on one side or two opposite sides of the surface of the annular cathode electrode frame close to the electrode plate or bipolar plate, one end or both ends of which are respectively connected to the cathode port end (outlet) of the cathode flow field and the cathode gas-liquid outlet channel of the AEM electrolyzer; there are one or two cathode ports, both of which are mainly used for hydrogen and liquid discharge (outlet), and also have nitrogen purge (one inlet and one outlet for purge gas when there are two); Anode distribution channels are provided on two opposite sides of the surface of one side of the annular anode electrode frame close to the electrode plate or bipolar plate, and the two ends thereof are respectively connected with the inlet and outlet ends of the anode flow field and the anode inlet and outlet channels of the AEM electrolytic cell; the two ends of the anode distribution channel on one side are respectively connected with the inlet end of the anode flow field and the anode inlet channel of the AEM electrolytic cell, and the two ends of the anode distribution channel on the other side are respectively connected with the outlet end of the anode flow field and the anode outlet channel of the AEM electrolytic cell.

9. The AEM electrolyzer according to claim 1, characterized in that: The cathode includes a cathode catalyst layer, or a cathode catalyst substrate and a cathode catalyst layer, the cathode catalyst layer is attached or coated on one side of the cathode catalyst substrate or the cathode side of the anion exchange membrane, and the cathode catalyst layer is arranged facing the anion exchange membrane side; The anode includes an anode catalyst layer, or includes an anode catalyst substrate and an anode catalyst layer, the anode catalyst layer is attached or coated on one side surface of the anode catalyst substrate or the anode side of the cation exchange membrane, and the anode catalyst layer faces and fits the anion exchange membrane, and the opposite side of the anode catalyst substrate faces and fits the foam metal (as a diffusion layer of the electrode); The cathode catalytic substrate and the anode catalytic substrate are respectively sheet structures with micropores, and can be one or more of mesh carbon paper, carbon cloth, metal wire mesh, and metal felt.

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