Electrolysis unit and electrolysis apparatus

Abstract

The present application provides an electrolysis unit comprising: first and second electrode plates; a stack formed by sequentially stacking an anode porous transport layer, an anode electrode layer, a membrane, a cathode electrode layer, and a cathode porous transport layer along a stacking direction, disposed between the first and second electrode plates in the stacking direction; and first and second sealing members disposed between the first and second electrode plates respectively in the stacking direction. The first sealing member surrounds the stack in a direction perpendicular to the stacking direction. The second sealing member is disposed outside the first sealing member and surrounds the member in a direction perpendicular to the stacking direction. The second sealing member is fixedly attached to the first and second electrode plates to maintain them as an integrated structure, thereby holding the first sealing member and the stack between the first and second electrode plates. The present application also provides an electrolysis apparatus comprising the aforementioned electrolysis unit. The electrolysis unit and electrolysis apparatus according to the present application are easy to manufacture, assemble, and maintain.

Description

[0001] DESCRIPTION

[0002] Electrolysis Unit and Electrolysis Apparatus

[0003] Technical Field

[0004] The present application generally relates to the field of electrolysis technology, and more particularly to an electrolysis unit for an electrolysis apparatus and an electrolysis apparatus comprising such an electrolysis unit.

[0005] Background

[0006] Hydrogen finds wide application across numerous fields, including chemical engineering, energy, transportation, and electronics. Various methods exist for hydrogen production, among which electrolysis technology constitutes a prominent research focus in the field of hydrogen production. In an exemplary alkaline solution electrolysis system, electrolyte is supplied to the electrolysis apparatus via a supply line, and water within the electrolyte undergoes electrolysis in the electrolysis apparatus. Reaction products (hydrogen and oxygen) and unconsumed electrolyte are conveyed from the electrolysis apparatus through a discharge line and separated from one another. The reaction products are subsequently purified and stored, whereas the unconsumed electrolyte is recirculated to the electrolysis apparatus via the supply line.

[0007] An electrolysis apparatus typically comprises a plurality of electrolysis units stacked together and end plates for holding these electrolysis units together. Each electrolysis unit typically comprises, in sequence, an anode plate, an anode porous transport layer, an anode electrode layer, a membrane (a diaphragm in alkaline solution electrolysis systems), a cathode electrode layer, a cathode porous transport layer, and a cathode plate (wherein the anode and cathode plates may be configured as bipolar or monopolar plates). These components are compressed together by pressure. Sequential stacking of the electrolysis unit components during manufacture of the electrolysis apparatus is time-consuming and susceptible to assembly errors, such as misalignment, deformation, and excessive stress, thereby resulting in low assembly efficiency and a high risk of quality issues.

[0008] Furthermore, during the service life of an electrolysis unit (e.g., up to 120,000 hours), certain components (e.g., membranes) of the electrolysis unit may become damaged or fail, thereby necessitating maintenance of the electrolysis apparatus. However, electrolysis units and apparatuses manufactured via the aforementioned process are difficult to disassemble and reassemble, and such maintenance may also cause damage to other electrolysis units or components.

[0009] Therefore, there exists an urgent need to improve existing electrolysis apparatuses and their electrolysis units.Summary of the Invention

[0010] The purpose of the present application is to provide an improved electrolysis unit and an electrolysis apparatus comprising the electrolysis unit, so as to overcome at least one of the defects in the prior art.

[0011] In one aspect, the present application provides an electrolysis unit for an electrolysis apparatus, comprising: a first electrode plate and a second electrode plate; a stack formed by sequentially stacking, along a stacking direction, an anode porous transport layer, an anode electrode layer, a membrane, a cathode electrode layer and a cathode porous transport layer, the stack being disposed between the first electrode plate and the second electrode plate in the stacking direction; and a first sealing member and a second sealing member respectively disposed between the first electrode plate and the second electrode plate in the stacking direction. The first sealing member surrounds the stack in a direction perpendicular to the stacking direction, and the second sealing member is disposed on the side of the first sealing member facing away from the stack in the direction perpendicular to the stacking direction and surrounds the first sealing member. The second sealing member is fixedly attached to the first electrode plate and the second electrode plate to maintain the first electrode plate and the second electrode plate as a single structure, thereby holding the first sealing member and the stack therebetween.

[0012] In another aspect, the present application provides an electrolysis apparatus, comprising: a plurality of electrolysis units, each of which is the aforementioned electrolysis unit, and the plurality of electrolysis units being stacked along the stacking direction; and a first end plate and a second end plate, the first end plate and the second end plate clamping the plurality of electrolysis units therebetween in the stacking direction to hold the plurality of electrolysis units together.

[0013] The electrolysis unit and electrolysis apparatus comprising such an electrolysis unit according to the present application are easy to manufacture, assemble and maintain, have high reliability and flexibility, and are significantly cost-effective.

[0014] These techniques may be used alone or in any suitable combination. The foregoing summary is provided by way of illustration and is not meant to be limiting.

[0015] Brief Description of the Drawings

[0016] The above and other aspects of the present disclosure will be understood and appreciated more thoroughly below in connection with the appended drawings. It should be noted that the drawings are merely illustrative and not drawn to scale. The same components are indicated by the same reference signs in different drawings. Additionally, for the sake of brevity, not all components or portions of the electrolysis apparatus and electrolysis unit thereof according to the present application are shown or labeled in the accompanying drawings. It should be understood that the dimensions, proportional relationships, and number of components or portions shown in the drawings are not to be considered as limitations on the present application. In the accompanying drawings:FIG. 1 is a schematic partial cross-sectional view of an electrolysis apparatus according to some examples of the present application;

[0017] FIG. 2 is a schematic cross-sectional view of an electrolysis unit comprised in the electrolysis apparatus of FIG. 1;

[0018] FIG. 3 is a schematic cross-sectional view of the electrolysis unit of FIG. 2 along line A-A in FIG. 2;

[0019] FIG. 4 is a schematic front view of an electrode plate of the electrolysis unit of FIG. 2; FIG. 5 is a schematic cross-sectional view of the electrode plate in FIG. 4 along line B-B in FIG. 4;

[0020] FIG. 6A is a schematic cross-sectional view of an alternative type of electrolysis unit that may be used in the electrolysis apparatus of FIG. 1;

[0021] FIG. 6B is an enlarged view of the area 6B in FIG. 6A;

[0022] FIG. 7A is a schematic cross-sectional view of another alternative type of electrolysis unit that may be used in the electrolysis apparatus of FIG. 1; and

[0023] FIG. 7B is an enlarged view of the area 7B in FIG. 7A.

[0024] Detailed Description of the Embodiments

[0025] Some examples of the present application are described in detail below in conjunction with the drawings. In the following examples, for the purpose of facilitating the description of the electrolysis apparatus and electrolysis unit thereof according to the present application, as well as the corresponding manufacturing and assembly method, an alkaline solution electrolysis apparatus and an electrolysis unit thereof are used as examples. It should be understood that such examples do not imply any limitation on the present application, and the electrolysis apparatus and its electrolysis unit or its variations according to the present application can be used in other types of electrolysis systems, such as proton exchange membrane (PEM) electrolysis systems, anion exchange membrane (AEM) electrolysis systems, etc. Furthermore, features in the examples of the present application may be combined with each other, provided there is no conflict.

[0026] FIG. 1 schematically illustrates an electrolysis apparatus 10 for an electrolysis system (not shown) according to some examples of the present application. The electrolysis system may be an alkaline solution electrolysis system using an alkaline solution (e.g., potassium hydroxide solution, sodium hydroxide solution, etc.) as the electrolyte. The electrolysis apparatus 10 is configured to electrolyze water in the alkaline electrolyte to generate hydrogen and oxygen. The electrolysis apparatus 10 may also be referred to as an “electrolysis cell” or “electrolysis tank.” The electrolysis apparatus 10 may comprise a housing (not shown) and a plurality of electrolysis units 20 housed within the housing.

[0027] The plurality of electrolysis units 20 may have the same or substantially the same configuration as one another. FIGS. 2 and 3 show one of the plurality of electrolysis units 20. Theelectrolysis unit 20 may also be referred to as a “single electrolysis cell.” As shown in FIG. 2, the electrolysis unit 20 comprises a first electrode plate (anode plate) 21, a second electrode plate (cathode plate) 22, and a stack formed by sequentially stacking, along a stacking direction 28, an anode porous transport layer 23, an anode electrode layer 24, a membrane (here, a diaphragm) 25, a cathode electrode layer 26, and a cathode porous transport layer 27. That is, the membrane 25 is located between the anode electrode layer 24 and the cathode electrode layer 26, the anode porous transport layer 23 is located on the side of the anode electrode layer 24 facing away from the membrane 25, and the cathode porous transport layer 27 is located on the side of the cathode electrode layer 26 facing away from membrane the 25. The layers may contact one another. The first electrode plate 21 and the second electrode plate 22 are spaced apart from each other in the stacking direction 28, and the stack is disposed between the first electrode plate 21 and the second electrode plate 22 in the stacking direction 28. The first electrode plate 21 is located on the side of the anode porous transport layer 23 facing away from the anode electrode layer 24, and the second electrode plate 22 is located on the side of the cathode porous transport layer 27 facing away from the cathode electrode layer 26. The first electrode plate 21 and the second electrode plate 22 may be electrically connected to an external DC power supply (not shown) and may be immersed in an electrolyte together with the stack. The membrane 25 allows ions to pass through but prohibits gas molecules from passing through.

[0028] Taking the electrolysis unit 20 as an example, during operation, the electrolyte circulates through the electrolysis unit 20, and an external DC power supply provides DC power to the first electrode plate 21 and the second electrode plate 22 of the electrolysis unit 20. At the cathode electrode layer 26, water molecules gain electrons to generate hydrogen molecules and hydroxide ions (i.e., a reduction reaction occurs: 4H2O + 4e~ 2H2+ 4OH'). Hydrogen molecules, unable to pass through the membrane 25, are discharged with the electrolyte, while hydroxide ions, driven by voltage, pass through the membrane 25 from the cathode electrode layer 26 to the anode electrode layer 24. At the anode electrode layer 24, hydroxide ions lose electrons to generate oxygen molecules and water molecules (i.e., an oxidation reaction occurs: 4OH' 2H2O + O2+ 4e_). Oxygen molecules, unable to pass through the membrane 25, are discharged with the electrolyte.

[0029] Following the same principle, each electrolysis unit 20 may receive electrolyte and, after the above-mentioned electrochemical reaction, discharge an electrolyte containing hydrogen on the cathode side (i.e., discharge the reaction products and unconsumed electrolyte on the cathode side), while simultaneously discharging an electrolyte containing oxygen on the anode side (i.e., discharge the reaction products and unconsumed electrolyte on the anode side). Accordingly, the electrolysis apparatus 10 is provided with a hydrogen-side (also known as a cathode side) outlet 10a for discharging the electrolyte containing hydrogen, an oxygen-side (also known as an anode side) outlet 10b for discharging the electrolyte containing oxygen, and an inlet 10c for receiving the electrolyte.As shown in FIGS. 2 and 3, each electrolysis unit 20 comprises an anode-side outlet manifold channel 20a, a cathode-side outlet manifold channel 20b, and an electrolyte inlet manifold channel 20c. When the plurality of electrolysis units 20 are stacked and held together along the stacking direction 28 as shown in FIG. 1, the anode-side outlet manifold channel 20a, cathode-side outlet manifold channel 20b and electrolyte inlet manifold channel 20c of the plurality of electrolysis units 20 are aligned in the stacking direction 28 to form an anode-side outlet manifold, a cathode-side outlet manifold and an electrolyte inlet manifold. The electrolyte inlet manifold distributes the electrolyte received through the inlet 10c to each electrolysis unit 20. The cathode-side outlet manifold collects the hydrogen-containing electrolyte discharged from each electrolysis unit 20 to the hydrogen-side outlet 10a, and the anode-side outlet manifold collects the oxygen-containing electrolyte discharged from each electrolysis unit 20 to the oxygen-side outlet 10b.

[0030] Referring again to FIGS. 2 and 3, each electrolysis unit 20 further comprises a first sealing member 30 and a second sealing member 40, which are respectively disposed between the first electrode plate 21 and the second electrode plate 22 in the stacking direction 28 to provide a seal that isolates the internal space of the electrolysis unit 20 for the flow of electrolyte from the outside of the electrolysis unit 20.

[0031] Specifically, the first sealing member 30 surrounds the stack formed by the anode porous transport layer 23, the anode electrode layer 24, the membrane 25, the cathode electrode layer 26, and the cathode porous transport layer 27 in a direction perpendicular to the stacking direction 28. In other words, the first sealing member 30 can surround the internal space of the electrolysis unit 20 for the flow of electrolyte to provide a seal, thereby isolating it from the outside of the electrolysis unit 20. The second sealing member 40 is disposed on the side of the first sealing member 30 facing away from the stack (hereinafter referred to as the “outer side”) in a direction perpendicular to the stacking direction 28 and surrounds the first sealing member 30. In this way, the second sealing member 40 can provide a second seal around the internal space of the electrolysis unit 20 to isolate it from the outside of the electrolysis unit 20, thereby further enhancing the sealing effect. The second sealing member 40 is also fixedly attached to the first electrode plate 21 and the second electrode plate 22 to hold the first electrode plate 21 and the second electrode plate 22 as an integrated structure. As used in the present application, an integrated structure means that the components are held together so that they can be moved together (e.g., moved to a designated location or position), installed (e.g., installed into the electrolysis apparatus 10), and removed (e.g., removed from the electrolysis apparatus 10). Since the first sealing member 30 and the stack are disposed between the first electrode plate 21 and the second electrode plate 22, holding the first electrode plate 21 and the second electrode plate 22 as an integrated structure using the second sealing member 40 allows the first electrode plate 21 and the second electrode plate 22 to hold the first sealing member 30 and the stack therebetween.In this way, the entire electrolysis unit 20 (i.e., the stack, the first electrode plate 21, the second electrode plate 22, the first sealing member 30, and the second sealing member 40) can be formed as an integrated unit, i.e., a single integral structure. During the manufacture of the electrolysis apparatus 10, the electrolysis apparatus 10 may be formed by first forming each electrolysis unit 20 as an integrated component and then stacking the individual electrolysis units 20 together. The integrated electrolysis unit 20 is easier to handle during the manufacture of the electrolysis apparatus 10, thereby improving the manufacturing efficiency of the electrolysis apparatus 10. Furthermore, the integrated electrolysis unit 20 can significantly reduce assembly errors (such as misalignment, deformation, excessive stress, etc.) during the manufacture of the electrolysis apparatus 10, thereby improving the quality of the electrolysis apparatus 10. When some components of the electrolysis unit 20 are damaged or fail and need to be replaced, the integrated electrolysis unit 20 is easier to disassemble, replace, and reassemble, thereby improving the maintenance efficiency of the electrolysis apparatus 10 and reducing its maintenance costs. Compared to existing electrolysis units 20 where components are held together by pressure, the integrated electrolysis unit 20 offers higher integration and reliability. Furthermore, the integrated electrolysis unit 20 allows for flexible increases or decreases in the number of electrolysis units 20 within the electrolysis apparatus 10 as needed, thereby improving the flexibility of the electrolysis apparatus 10. Therefore, the electrolysis unit 20 and the electrolysis apparatus 10 comprising such an electrolysis unit 20 according to the present application are easy to manufacture, assemble and maintain, have high reliability and flexibility, and are significantly cost-effective.

[0032] The first sealing member 30 isolates the second sealing member 40 from the aforementioned stack. That is, the first sealing member 30 isolates the second sealing member 40 from the internal space of the electrolysis unit 20 for the flow of electrolyte. With this configuration, the first sealing member 30 forms a first seal (or “primary seal”), and the second sealing member 40 forms a second seal (or “secondary seal”) outside the first sealing member 30. This dual sealing improves the reliability and service life of the electrolysis unit 20.

[0033] As shown in FIGS. 2 and 3, in each electrolysis unit 20, each of the following components can extend through the first sealing member 30 along the stacking direction 28: the anode-side outlet manifold channel 20a, the cathode-side outlet manifold channel 20b, and the electrolyte inlet manifold channel 20c. In other words, the first sealing member 30 may comprise a plurality of orifices extending through the sealing member 30 along the stacking direction 28, which may respectively form a section of the anode-side outlet manifold channel 20a, the cathode-side outlet manifold channel 20b, and the electrolyte inlet manifold channel 20c. With this configuration, the first sealing member 30 forms a first seal around each manifold channel, and the second sealing member 40 forms a second seal outside the first sealing member 30. Providing a double seal around each manifold channel can further improve the reliability and service life of the electrolysis unit 20.In applications where the electrolysis unit 20 is used to electrolyze water in an alkaline electrolyte, the first sealing member 30 may be made of a sealing material resistant to alkaline electrolyte corrosion. For example, the sealing material may be polytetrafluoroethylene (PTFE). Exemplarily, the first sealing member 30 may be formed in the form of a sealing gasket.

[0034] In some examples, a stack formed by sequentially stacking an anode porous transport layer 23, an anode electrode layer 24, a membrane 25, a cathode electrode layer 26, and a cathode porous transport layer 27 along a stacking direction 28, and a first sealing member 30, may be clamped between a first electrode plate 21 and a second electrode plate 22 along the stacking direction 28, respectively. That is, the stack and the first sealing member 30 are held together by the clamping force applied by the first electrode plate 21 and the second electrode plate 22, respectively. As will be specifically described below, for the manufactured electrolysis unit 20, the clamping force of the first electrode plate 21 and the second electrode plate 22 is provided by a second sealing member 40 that holds the first electrode plate 21 and the second electrode plate 22 as an integrated structure. When the plurality of electrolysis units 20 are assembled in the electrolysis apparatus 10, a clamp 50 (FIG. 1) applies a clamping force to the plurality of electrolysis units 20 to hold the plurality of electrolysis units 20 together. In this case, the clamping force of the first electrode plate 21 and the second electrode plate 22 on the stack is further provided by the clamp 50.

[0035] In some examples, as best illustrated in FIG. 2, the first sealing member 30 may receive at least the edges of the anode electrode layer 24, the membrane 25 and the cathode electrode layer 26 in a direction perpendicular to the stacking direction 28 therein, so as to at least hold the anode electrode layer 24, the membrane 25 and the cathode electrode layer 26 as an integrated structure.

[0036] For example, the first sealing member 30 may receive the edges of the anode electrode layer 24, the membrane 25, and the cathode electrode layer 26 therein (e.g., the first sealing member 30 is molded on the edges) to hold the anode electrode layer 24, the membrane 25, and the cathode electrode layer 26 as an integrated structure. With this configuration, the first sealing member 30, the anode electrode layer 24, the membrane 25, and the cathode electrode layer 26 can be formed as an integrated structure, i.e. , a monolithic structure. During the manufacture of the electrolysis unit 20, an integrated electrolysis unit 20 may be formed by first forming the first sealing member 30, the anode electrode layer 24, the membrane 25, and the cathode electrode layer 26 as an integrated structure, then stacking the first electrode plate 21 , the second electrode plate 22, the anode porous transport layer 23, and the cathode porous transport layer 27 together with this integrated structure in the aforementioned manner, and then using the second sealing member 40 to hold the first electrode plate 21 and the second electrode plate 22 as an integrated structure. The first sealing member 30, the anode electrode layer 24, the membrane 25 and the cathode electrode layer 26, which are formed as an integrated structure, are easier to handle when manufacturing the electrolysis unit 20, thereby improving the manufacturing efficiency ofthe electrolysis unit 20. In addition, this integrated structure can significantly reduce assembly errors (such as misalignment, deformation, excessive stress, etc.) when assembling the electrolysis unit 20, thereby improving the quality of the electrolysis unit 20. When some components of the electrolysis unit 20 are damaged or fail and need to be replaced, this integrated structure makes it easier to disassemble, replace, and reassemble, thereby improving the maintenance efficiency of the electrolysis unit 20 and reducing its maintenance costs. Compared to the components of the electrolysis unit 20 in the prior art, which are held together by pressure, this integrated structure has higher integration and reliability. Therefore, this integrated structure can further improve the integration, manufacturability, and reliability of the electrolysis unit 20.

[0037] For example, the first electrode plate 21 may be integrally formed with the anode porous transport layer 23 (e.g., by bonding), and the second electrode plate 22 may be integrally formed with the cathode porous transport layer 27 (e.g., by bonding). These two integrated structures may then be stacked together with an integrated structure formed by the first sealing member 30, the anode electrode layer 24, the membrane 25, and the cathode electrode layer 26. Subsequently, the first electrode plate 21 and the second electrode plate 22 may be held together using the second sealing member 40 to maintain these structures together, thereby forming an integrated electrolysis unit 20. In this way, the integration, manufacturability, and reliability of the electrolysis unit 20 can be further improved.

[0038] For example, the first sealing member 30 may receive the edges of the anode porous transport layer 23, the anode electrode layer 24, the membrane 25, the cathode electrode layer 26, and the cathode porous transport layer 27 in a direction perpendicular to the stacking direction 28 (e.g., the first sealing member 30 is molded on the edges) to hold the anode porous transport layer 23, the anode electrode layer 24, the membrane 25, the cathode electrode layer 26, and the cathode porous transport layer 27 into an integrated structure. During the manufacture of the electrolysis unit 20, the first electrode plate 21 and the second electrode plate 22 may be disposed on both sides of the integrated structure, and the first electrode plate 21 and the second electrode plate 22 may be held together by the second sealing member 40 to form an integrated electrolysis unit 20. In this way, the integration, manufacturability, and reliability of the electrolysis unit 20 can be further improved.

[0039] In some examples, the second sealing member 40 may be bonded between the first electrode plate 21 and the second electrode plate 22 to be fixedly attached to the first electrode plate 21 and the second electrode plate 22, thereby maintaining the first electrode plate 21 and the second electrode plate 22 as an integrated structure. That is, the first electrode plate 21 and the second electrode plate 22 can be maintained as an integrated structure at least by the adhesive force provided by the second sealing member 40.

[0040] For example, the second sealing member 40 may be formed of a sealant. Exemplarily, the sealant can be a silicone sealant, an epoxy resin sealant, or an acrylic sealant. The sealant may be applied to at least one of the opposing surfaces of the first electrode plate 21 and the secondelectrode plate 22 during assembly of the electrolysis unit 20, and then pressure is applied to hold the first electrode plate 21 and the second electrode plate 22 together and allow the sealant to cure, thereby bonding the first electrode plate 21 and the second electrode plate 22 into an integrated structure.

[0041] Alternatively, the second sealing member 40 may be formed of an adhesive film. That is, the second sealing member 40 may first be manufactured as an adhesive film with a specific pattern, the pattern being formed corresponding to the position where the second sealing member 40 is to be positioned between the first electrode plate 21 and the second electrode plate 22. Subsequently, during the assembly of the electrolysis unit 20, the adhesive film may be placed on at least one of the opposing surfaces of the first electrode plate 21 and the second electrode plate 22, and then pressure may be applied to hold the first electrode plate 21 and the second electrode plate 22 together, thereby bonding the first electrode plate 21 and the second electrode plate 22 into an integrated structure. Compared to a manufacturing process that applies sealant, the adhesive film can improve the placement efficiency of the second sealing member 40, thereby improving the manufacturing efficiency of the electrolysis unit 20. For example, the adhesive film can be made of epoxy resin sealant or acrylic sealant. Specifically, the adhesive film may first be supported and held by a release film, and the adhesive film may be moved from the release film to the electrode plate during placement.

[0042] The first sealing member 30 is arranged inward and in direct contact with the electrolyte, while the second sealing member 40 is arranged outside the first sealing member 30 and provides a second seal and adhesion to hold the first electrode plate 21 and the second electrode plate 22 together. Therefore, the first sealing member 30 may be made of a sealing material more resistant to electrolyte corrosion, such as PTFE in applications where the electrolysis unit 20 is used to electrolyze water in an alkaline electrolyte. Furthermore, the second sealing member 40 may be formed using a more viscous sealing material without concern for electrolyte corrosion (although alkaline corrosion is present here, acidic corrosion may also exist in other examples). This is because the second sealing member 40 is located outside the first sealing member 30 and is separated from the aforementioned stack by the first sealing member 30, thus the requirement for the material used to manufacture the second sealing member 40 to be resistant to electrolyte corrosion is not as high. Since the second sealing member 40 does not directly contact the electrolyte, the adhesion is more reliable. The inventors have recognized and realized that this double seal (or hybrid seal) can provide a reliable seal while reliably holding the first electrode plate 21 and the second electrode plate 22 together, thereby improving the reliability and service life of the electrolysis unit 20.

[0043] In some examples, as shown in FIGS. 2 and 3, the second sealing member 40 may be configured to contact the first sealing member 30 in a direction perpendicular to the stacking direction 28 to bond the first sealing member 30 to the first electrode plate 21 and the second electrode plate 22. In this way, displacement of the first sealing member 30 can be prevented(e.g., due to changes in clamping force when the electrolysis unit 20 is installed into or removed from the electrolysis apparatus 10, or due to thermal expansion and contraction caused by temperature changes during operation of the electrolysis apparatus 10), thereby further improving the reliability of the electrolysis unit 20.

[0044] In other examples, the second sealing member 40 may be spaced apart from the first sealing member 30 in a direction perpendicular to the stacking direction 28. For example, a gap may exist between the second sealing member 40 and the first sealing member 30 in a direction perpendicular to the stacking direction 28, so that the first sealing member 30 and the second sealing member 40 do not contact each other. On the one hand, compared to the case where the second sealing member 40 is in contact with the first sealing member 30, separating the second sealing member 40 from the first sealing member 30 can prevent the second sealing member 40 from being moved by the first sealing member 30 due to thermal expansion and contraction caused by temperature changes during the operation of the electrolysis apparatus 10, thereby causing adhesion failure. On the other hand, separating the second sealing member 40 from the first sealing member 30 facilitates the disassembly of the electrolysis unit 20 when some of its components are damaged or fail and require repair, thereby improving the maintenance efficiency of the electrolysis unit 20 and reducing its maintenance costs.

[0045] In some examples, the first electrode plate 21 may be a single electrode plate (i.e., an anode plate). The first electrode plate 21 may be formed of a metallic material or a composite material. FIGS. 4 and 5 specifically illustrate an exemplary form of the first electrode plate 21. As shown in FIGS. 4 and 5, the first electrode plate 21 may comprise a first electrode plate body 21a and a first electrode frame 21b surrounding the first electrode plate body 21 a in a direction perpendicular to the stacking direction 28. The first electrode frame 21b is fixed to the first electrode plate body 21a or integrally formed with the first electrode plate body 21a. For example, the first electrode frame 21b may be fixed to the first electrode plate body 21 a by any suitable means or mechanism (e.g., adhesive, snap-fit, welding). In this case, the first electrode plate body 21a and the first electrode frame 21b may be formed of the same or different materials. Exemplarily, the first electrode plate body 21a may be formed of a metallic material such as nickel, and the first electrode frame 21b may be formed of a metallic material or a resin material. For example, the first electrode frame 21b may be integrally formed with the first electrode plate body 21a by any suitable process such as stamping or machining. In this case, the first electrode plate body 21a and the first electrode frame 21 b are formed of the same material.

[0046] In some examples, as shown in FIGS. 4 and 5, the first electrode plate body 21a may comprise a recess 21c recessed therein along the stacking direction 28. The recess 21c is configured to at least partially receive the anode porous transport layer 23, i.e., to receive a portion of the aforementioned stack. A first electrode frame 21b surrounds the first electrode plate body 21a in a direction perpendicular to the stacking direction 28. Each of the following components may extend through the first electrode frame 21b along the stacking direction 28: the anode-sideoutlet manifold channel 20a, the cathode-side outlet manifold channel 20b, and the electrolyte inlet manifold channel 20c. In other words, the first electrode frame 21b may comprise a plurality of orifices extending through the first electrode frame 21b along the stacking direction 28. These orifices may respectively form a section of the anode-side outlet manifold channel 20a, the cathode-side outlet manifold channel 20b, and the electrolyte inlet manifold channel 20c. A groove may be provided within the recess 21c, and electrolyte and reaction products may flow along the groove. Therefore, the recess 21c may define the anode-side flow field. The first electrode plate 21 may also comprise an input channel 21 d and an output channel 21 e, wherein the input channel 21 d communicates with the electrolyte inlet manifold channel 20c and the recess 21c for inputting electrolyte from the electrolyte inlet manifold channel 20c into the anode-side flow field of the electrolysis unit 20, and the output channel 21 e communicates with the recess 21c and the anodeside outlet manifold channel 20a for discharging anode-side reaction products and unconsumed electrolyte from the anode-side flow field to the anode-side outlet manifold channel 20a. It should be understood that the specific configuration of the first electrode plate 21 is not limited thereto. For example, in other examples, the first electrode plate body 21a may not have the recess 21c.

[0047] As shown in FIG. 2, the second electrode plate 22 is also a single electrode plate (i.e., a cathode plate), and its configuration is similar to that of the first electrode plate 21. Specifically, the structure of the second electrode plate 22 may be substantially symmetrical to the structure of the first electrode plate 21. Furthermore, the second electrode plate 22 may be made of a material similar to that of the first electrode plate 21. Similar to the first electrode plate 21, the second electrode plate 22 may also comprise a second electrode plate body 22a and a second electrode frame 22b surrounding the second electrode plate body 22a in a direction perpendicular to the stacking direction 28. The second electrode frame 22b is fixed to the second electrode plate body 22a or integrally formed with the second electrode plate body 22a. For the sake of simplicity, details of these similar contents will not be elaborated further.

[0048] As shown in FIG. 2, the first sealing member 30 and the second sealing member 40 may be respectively disposed between the first electrode frame 21b and the second electrode frame 22b in the stacking direction 28, and the aforementioned stack is disposed between the first electrode plate body 21a and the second electrode plate body 22a in the stacking direction 28. For example, the stack may be sandwiched between the first electrode plate body 21a and the second electrode plate body 22a in the stacking direction 28, and the first sealing member 30 may be sandwiched between the first electrode frame 21b and the second electrode frame 22b in the stacking direction 28. In addition, the second sealing member 40 may be bonded between the first electrode frame 21 b and the second electrode frame 22b to be fixedly attached to the first electrode plate 21 and the second electrode plate 22, thereby maintaining the first electrode plate 21 and the second electrode plate 22 as an integrated structure.

[0049] In some examples, the surfaces of each of the first electrode frame 21b and the second electrode frame 22b that face the second sealing member 40 are roughened by any suitableprocess. This configuration enhances the adhesion between the second sealing member 40 and the first electrode frame 21b and the second electrode frame 22b.

[0050] In some examples, the second sealing member 40 may provide an adhesive force of at least 10 N / mm (based on peel strength) or at least 1 MPa (based on shear strength) between itself and each of the first electrode plate 21 and the second electrode plate 22. This may be measured according to peel strength test standards such as GB / T 7122, ASTM D1876, or EN 1464, or any other suitable test method.

[0051] Referring back to FIG. 1, the electrolysis apparatus 10 comprises a plurality of electrolysis units 20 and a clamp 50. The plurality of electrolysis units 20 are stacked on top of each other along a stacking direction 28. The clamp 50 may comprise a first end plate 51 , a second end plate 52, and a third end plate 53. The second end plate 52 is disposed between the first end plate 51 and the third end plate 53 in the stacking direction 28. The clamp 50 may also comprise a plurality of connecting rods 54 connecting the first end plate 51, the second end plate 52, and the third end plate 53. The first end plate 51 and the third end plate 53 are fixed relative to each other by the connecting rods 54. That is, the first end plate 51 and the third end plate 53 are both fixed end plates. The second end plate 52 is slidable relative to the first end plate 51 and the third end plate 53 along the stacking direction 28 on the connecting rods 54. That is, the second end plate 52 is a movable end plate. The first end plate 51 and the second end plate 52 are configured to hold the stack formed by the plurality of electrolysis units 20 therebetween in the stacking direction 28, so as to keep the plurality of electrolysis units 20 together. The clamp 50 may further comprise a device 55 configured to drive the second end plate 52 to move relative to the first end plate 51 in the stacking direction 28. In this way, the device 55 may apply pressure to the second end plate 52 such that the second end plate 52 and the first end plate 51 exert a clamping force on the stack of electrolysis units 20 located therebetween, thereby reliably holding the plurality of electrolysis units 20 together. The device 55 may adjust the clamping force applied to the stack of electrolysis units 20 by adjusting the position of the second end plate 52 relative to the first end plate 51 in the stacking direction 28. The clamp 50 may also be referred to as a “holding mechanism” or a “holding device.”

[0052] This configuration of the clamp 50 of the electrolysis apparatus 10 makes it easier to install the electrolysis unit 20 into and remove and replace the electrolysis unit 20 from the electrolysis apparatus 10, thereby significantly improving the maintenance efficiency of the electrolysis apparatus 10 and reducing its maintenance costs.

[0053] In some examples, as shown in FIG. 1, the hydrogen-side outlet 10a, oxygen-side outlet 10b, and inlet 10c of the electrolysis apparatus 10 are all located at the first end plate 51. lt should be understood that the present application is not limited thereto, and in other examples, one or more of the following components may be located at the second end plate 52: the hydrogen-side outlet 10a, oxygen-side outlet 10b, and inlet 10c.

[0054] In some examples, the device 55 may be a hydraulic drive device, fixed to the third endplate 53, and hydraulically driving the second end plate 52 to move relative to the first end plate 51 in the stacking direction 28. The use of a hydraulic drive device provides a reliable clamping force and allows for precise adjustment of the clamping force.

[0055] Furthermore, the maintenance cost of a hydraulic drive device is low. It should be understood that in other examples, any other suitable type of device may be used to adjust the position of the second end plate 52 relative to the first end plate 51 in the stacking direction 28, thereby adjusting the clamping force applied by the first end plate 51 and the second end plate 52 to the stacking of the electrolysis unit 20.

[0056] In some examples, as shown in FIG. 1, thanks to the integrated unit design of the electrolysis unit 20 and the aforementioned configuration of the clamp 50, the plurality of electrolysis units 20 of the electrolysis apparatus 10 may be stacked horizontally. In other words, the stacking direction 28 may be horizontally oriented relative to the direction of gravity. As described in the Background, in conventional electrolysis apparatuses, the components are held together by pressure. More specifically, in conventional electrolysis apparatuses, the individual electrolysis units must be stacked one on top of the other along the direction of gravity. This results in conventional electrolysis apparatuses having a very high vertical height (e.g., reaching 5 meters or more), and their assembly and maintenance are time-consuming and labor-intensive. Compared to conventional electrolysis apparatuses, since the stacking direction 28 in the electrolysis apparatus 10 according to the present application is horizontally oriented relative to the direction of gravity, the electrolysis apparatus 10 can have a significantly reduced vertical height and can be easily assembled and maintained.

[0057] In other examples, the stacking direction 28 may also be oriented parallel to the direction of gravity. In this case, the electrolysis apparatus 10 can still be easily assembled and maintained.

[0058] In some examples, as shown in FIG. 1, sealing gaskets 60 may be provided between adjacent electrolysis units 20 to provide a seal therebetween. For example, the sealing gaskets 60 may be made of PTFE. The sealing gaskets 60 are held between adjacent electrolysis units 20 by clamping forces applied by the second end plate 52 and the first end plate 51.

[0059] Although the method described herein is to connect the first end plate 51, the second end plate 52, and the third end plate 53 using several connecting rods 54, it should be understood that any other type of structure may be used to achieve the fixation of the first end plate 51 and the third end plate 53 and to allow the second end plate 52 to move relative to the first end plate 51 in the stacking direction 28.

[0060] Furthermore, although the third end plate 53 is described herein as a fixed end plate, and the device 55 (e.g., a hydraulic drive device) is fixed to the third end plate 53, it should be understood that the third end plate 53 is merely one example of a fixing structure, and the present application is not limited thereto. In other examples, any other suitable fixing structure may be used to fix the first end plate 51 and the device 55.

[0061] The inventors have recognized and realized the method for manufacturing the electrolysisunit 20. Specifically, a stack formed by sequentially stacking an anode porous transport layer 23, an anode electrode layer 24, a membrane 25, a cathode electrode layer 26, and a cathode porous transport layer 27 along a stacking direction 28, and a first sealing member 30 are disposed between the first electrode plate 21 and the second electrode plate 22 in the stacking direction 28.

[0062] Then, the first electrode plate 21 and the second electrode plate 22 are held as an integrated structure by fixing the second sealing member 40 to the first electrode plate 21 and the second electrode plate 22 in a fixed manner (e.g., by adhesive). In this way, the entire electrolysis unit 20 (i.e., the stack, the first electrode plate 21 , the second electrode plate 22, the first sealing member 30, and the second sealing member 40) can be formed as an integrated unit, i.e., a single integral structure.

[0063] In various examples, the steps for disposing the stack and the first sealing member 30 between the first electrode plate 21 and the second electrode plate 22 may differ depending on the different configurations of the stack and the first sealing member 30 described above. Since these steps have already been described above in conjunction with different configurations of the stack and the first sealing member 30, these repetitive parts will not be repeated here. Furthermore, since various methods for disposing of the second sealing member 40 have already been described above in conjunction with different configurations of the second sealing member 40, these repetitive parts will not be repeated here either.

[0064] The inventors have also recognized and realized the method for manufacturing the electrolysis apparatus 10. Specifically, as shown in FIG. 1, a plurality of electrolysis units 20 and corresponding sealing gaskets 60 may be alternately stacked between the second end plate 52 and the first end plate 51 of the clamp 50 along the stacking direction 28. Subsequently, the second end plate 52 may be driven to move toward the first end plate 51 in the stacking direction 28 by a control device 55 to increase the clamping force exerted by the second end plate 52 and the first end plate 51 on the plurality of electrolysis units 20 and the corresponding sealing gaskets 60, thereby reliably holding them in place. That is, for each electrolysis unit 20, during the assembly of the electrolysis unit 20 into the electrolysis apparatus 10, the second sealing member 40 applies a clamping force by being fixedly attached to the first electrode plate 21 and the second electrode plate 22 to hold the aforementioned stack and the first sealing member in the electrolysis unit 20 between the second end plate 52 and the first end plate 51. In the assembled electrolysis apparatus 10, the clamping force of the first electrode plate 21 and the second electrode plate 22 on the stack and the first sealing member 30 is further applied by the clamp 50.

[0065] The inventors have also recognized and realized a method for disassembling and maintaining the electrolysis apparatus 10. Specifically, the second end plate 52 may be moved away from the first end plate 51 in the stacking direction 28 by a control device 55 to reduce the clamping force exerted by the second end plate 52 and the first end plate 51 on the plurality ofelectrolysis units 20 and the corresponding sealing gaskets 60, thereby allowing the electrolysis units 20 that need to be replaced to be removed from the electrolysis apparatus 10. Subsequently, a new electrolysis unit 20 may be quickly installed into the electrolysis apparatus 10 and the clamping force may be reapplied to hold the plurality of electrolysis units 20 and the corresponding sealing gaskets 60 together, so that the electrolysis apparatus 10 may be restored to operation. The replaced electrolysis units 20 may then be returned to the factory for repair.

[0066] The inventors have further recognized and realized that structures capable of enhancing the adhesion between the second sealing member 40 and the first electrode plate 21 and the second electrode plate 22 are available. FIGS. 6A to 7B illustrate two exemplary types of electrolysis units employing such structures, namely, electrolysis units 620 and 720. The configuration, manufacturing, and assembly methods of electrolysis units 620 and 720 are similar to those of electrolysis unit 20 shown in FIGS. 1 to 5.

[0067] Therefore, for components or portions in the electrolysis units 620 and 720 that are the same as or similar to those in the electrolysis unit 20, the same or similar components or portions in the electrolysis units 620 and 720 will be labeled in FIGS. 6A to 7B using the same reference signs used to label the components or portions in the electrolysis unit 20 in FIGS. 1 to 5. For the sake of brevity, the details of the configuration, manufacturing, and assembly methods of these same or similar components or portions will not be repeated, and the unique features of the electrolysis units 620 and 720 will be described in detail below.

[0068] As shown in FIGS. 6A and 6B, at least one of the first electrode frame 21b of the first electrode plate 21 and the second electrode frame 22b of the second electrode plate 22 of the electrolysis unit 620 (each in the figures) may comprise a groove 621 recessed therein along the stacking direction 28. The groove 621 has a narrower entrance portion 621a and a wider inner portion 621b in the stacking direction 28. The second sealing member 40 comprises a first portion 40a disposed in the groove 621 of the first electrode frame 21 b and a second portion 40b disposed in the groove 621 of the second electrode frame 22b. The first portion 40a and the second portion 40b each fill the corresponding groove 621. With this configuration, the adhesion between the second sealing member 40 and the first electrode frame 21 b and the second electrode frame 22b can be enhanced. Specifically, on the one hand, the groove 621 can increase the bonding area between the second sealing member 40 and the first electrode frame 21b and the second electrode frame 22b, thereby enhancing the adhesion. On the other hand, the shape of the groove 621 allows the first portion 40a and the second portion 40b of the second sealing member 40 to snap into the corresponding groove 621, thereby enhancing the adhesion.

[0069] As shown in FIG. 6B, when viewed in cross-section, the groove 621 may comprise a narrow entrance portion 621a with a narrow neck shape and a wide inner portion 621b with a rounded head shape. It should be understood that the shape of the groove 621 is not limited to this. In other examples, the cross-section of the groove 621 may be dovetail-shaped (inverted trapezoidal) or any other suitable shape.In some examples, the groove 621 may be continuous and annular. In other examples, the groove 621 may be discontinuous (e.g., comprising a single segment or a plurality of separate segments). For example, the groove 621 may be provided at locations where higher adhesion is required.

[0070] As shown in FIGS. 7A and 7B, the first electrode frame 21b of the first electrode plate 21 of the electrolysis unit 720 may comprise a first body 721a and a first annular protrusion 721b (one in the figures) protruding from the first body 721a along the stacking direction 28 toward the second electrode frame 22b of the second electrode plate 22. The second electrode frame 22b of the second electrode plate 22 may comprise a second body 722a and a second annular protrusion 722b (one in the figures) protruding from the second body 722a along the stacking direction 28 toward the first electrode frame 21 b of the first electrode plate 21. The first annular protrusion 721b and the second annular protrusion 722b are staggered from each other in the stacking direction 28. The first annular protrusion 721b and the second annular protrusion 722b are spaced apart from each other in a direction perpendicular to the stacking direction 28 to define a gap therebetween. The second sealing member 40 is disposed in the gap and is positioned between the top of the first annular protrusion 721b and the second body 722a of the second electrode frame 22b, and between the top of the second annular protrusion 722b and the first body 721a of the first electrode frame 21b. With this configuration, the adhesion between the second sealing member 40 and the first electrode frame 21 b and the second electrode frame 22b can be enhanced. Specifically, the first annular protrusion 721 b and the second annular protrusion 722b increase the bonding area between the second sealing member 40 and the first electrode frame 21b and the second electrode frame 22b, thereby enhancing the adhesion. Furthermore, the first annular protrusion 721b and the second annular protrusion 722b enable the second sealing member 40 to form a labyrinthine sealing structure in a direction perpendicular to the stacking direction 28. This increases the total length of the fluid movement path from the inside to the outside of the electrolysis unit 20, thereby improving the sealing effect. Furthermore, the first annular protrusion 721b and the second annular protrusion 722b can reliably hold the second sealing member 40 in place, in particular preventing the second sealing member 40 from deforming or shifting in a direction perpendicular to the stacking direction 28, thereby improving the sealing effect.

[0071] As shown in FIG. 7B, when viewed in cross-section, the first annular protrusion 721b and the second annular protrusion 722b may each have a trapezoidal shape. It should be understood that the cross-sectional shape of the first annular protrusion 721b and the second annular protrusion 722b is not limited to this. In other examples, the cross-sections of the first annular protrusion 721b and the second annular protrusion 722b may be triangular, rectangular, semicircular, or any other suitable shape.

[0072] Although only one first annular protrusion 721b and one second annular protrusion 722b are shown in FIGS. 7A and 7B, it should be understood that the first electrode frame 21b of thefirst electrode plate 21 and the second electrode frame 22b of the second electrode plate 22 of the electrolysis unit 720 may each have more than one annular protrusion. That is, the first electrode frame 21b may comprise at least one first annular protrusion 721b protruding from the first body 721a along the stacking direction 28 toward the second electrode frame 22b, and the second electrode frame 22b may comprise at least one second annular protrusion 722b protruding from the second body 722a along the stacking direction 28 toward the first electrode frame 21b. At least one first annular protrusion 721b and at least one second annular protrusion 722b are staggered from each other in the stacking direction 28 and are arranged alternately in a direction perpendicular to the stacking direction 28. Adjacent first annular protrusions 721b and second annular protrusions 722b are spaced apart from each other in a direction perpendicular to the stacking direction 28 to define a gap therebetween. The second sealing member 40 is disposed in the gap and between the top of at least one first annular protrusion 721b and the second body 722a of the second electrode frame 22b, and between the top of at least one second annular protrusion 722b and the first body 721 a of the first electrode frame 21b. This configuration enhances the adhesion between the second sealing member 40 and the first electrode frame 21b and the second electrode frame 22b, and improves the sealing effect of the second sealing member 40.

[0073] Although the foregoing description describes the second sealing member 40 being bonded between the first electrode plate 21 and the second electrode plate 22 to be fixedly attached to the first electrode plate 21 and the second electrode plate 22, thereby maintaining the first electrode plate 21 and the second electrode plate 22 as an integrated structure, it should be understood that the second sealing member 40 may be fixedly attached to the first electrode plate 21 and the second electrode plate 22 by any other suitable means to maintain the first electrode plate 21 and the second electrode plate 22 as an integrated structure. For example, the second sealing member 40 may be heat-fused or ultrasonically welded to the first electrode plate 21 and the second electrode plate 22. Furthermore, the second sealing member 40 may have a rigid body and protrusions extending from the body (e.g., the first portion 40a and the second portion 40b shown in FIG. 6B). A deformation layer may be provided on the outer side of the protrusions. Exemplarily, the body and protrusions of the second sealing member 40 may be formed of a resin material. The deformation layer is made of a material that is less hard and more elastic than the resin material, such as fluororubber, EPDM rubber, silicone rubber, or polytetrafluoroethylene. The protrusion of the second sealing member 40 can be directly snapped into the groove 621 of the first electrode plate 21 and the second electrode plate 22 by means of the deformation layer, to achieve a reliable mechanical attachment and tight seal between the first electrode plate 21 and the second electrode plate 22. Alternatively, the second sealing member 40 may be vulcanized to fixably attach the first electrode plate 21 and the second electrode plate 22, thereby maintaining the first electrode plate 21 and the second electrode plate 22 as an integrated structure. Yet another example is that the second sealing member 40 may be fixedly attached tothe first electrode plate 21 and the second electrode plate 22 by a hot-melt rivet. For example, the first electrode plate 21 and the second electrode plate 22 may each be perforated along the stacking direction 28, and a hot-melt rivet may extend through the hole and be hot-melted and fixed in place to securely attach the second sealing member 40 to the first electrode plate 21 and the second electrode plate 22.

[0074] Furthermore, although the configuration of the first electrode plate 21 and the second electrode plate 22 is described herein using a single electrode plate as an example, it should be understood that the first electrode plate 21 and the second electrode plate 22 may also be bipolar plates respectively, and are equally applicable to the electrolysis unit 20 of the present application. In this case, the electrolysis apparatus 10 may comprise at least one additional electrolysis unit, which is arranged alternately with the electrolysis unit 20 along the stacking direction 28 in the electrolysis apparatus 10. Each additional electrolysis unit may comprise a stack formed of an anode porous transport layer, an anode electrode layer, a membrane (here, a diaphragm), a cathode electrode layer, and a cathode porous transport layer, and a sealing member (e.g., the aforementioned first sealing member 30 or other sealing gaskets). The stack and sealing member of each additional electrolysis unit may be held in place by the bipolar plates of the adjacent electrolysis unit 20. Therefore, in the present application, bipolar plates and single electrode plates may be collectively referred to as electrode plates.

[0075] Furthermore, although the electrolysis unit 20 is described herein for electrolyzing water in an alkaline electrolyte, it should be understood that the electrolysis apparatus 10 and its electrolysis unit 20, or variations thereof, according to the present application can be used in other types of electrolysis systems, such as PEM electrolysis systems, AEM electrolysis systems, etc. In the application of the electrolysis unit 20 in a PEM electrolysis system, the membrane 25 is a proton exchange membrane. In the application of the electrolysis unit 20 in an AEM electrolysis system, the membrane 25 is an anion exchange membrane. Furthermore, the configuration of the inlet manifold and outlet manifold may be changed accordingly.

[0076] In the present application, the terms “first,” “second,” etc., are used only to distinguish one component, pipeline, or mode from another component, pipeline, or mode, but these components, pipelines, and modes should not be limited by such terms.

[0077] The present application has been described in detail in conjunction with specific examples. It is evident that the above description and the examples illustrated in the accompanying drawings are all to be understood as exemplary and not as limiting the present application. Those skilled in the art may make various modifications or alterations without departing from the spirit of the present application, and such modifications or alterations are not to be excluded from the scope of the present application.

Claims

CLAIMS1. An electrolysis unit (20, 620, 720) for an electrolysis apparatus (10), comprising: a first electrode plate (21) and a second electrode plate (22);a stack formed by sequentially stacking an anode porous transport layer (23), an anode electrode layer (24), a membrane (25), a cathode electrode layer (26), and a cathode porous transport layer (27) along a stacking direction (28), wherein the stack is disposed between the first electrode plate and the second electrode plate in the stacking direction; anda first sealing member (30) and a second sealing member (40) respectively disposed between the first electrode plate and the second electrode plate in the stacking direction, wherein the first sealing member surrounds the stack in a direction perpendicular to the stacking direction, and the second sealing member is disposed on the side of the first sealing member facing away from the stack and surrounds the first sealing member in a direction perpendicular to the stacking direction, the second sealing member being fixedly attached to the first electrode plate and the second electrode plate to hold the first electrode plate and the second electrode plate as an integrated structure, allowing the first electrode plate and the second electrode plate to hold the first sealing member and the stack therebetween.

2. The electrolysis unit according to claim 1, wherein the first sealing member receives at least the edges of the anode electrode layer, the membrane, and the cathode electrode layer in the direction perpendicular to the stacking direction therein, so as to at least maintain the anode electrode layer, the membrane, and the cathode electrode layer as an integrated structure.

3. The electrolysis unit according to claim 2, wherein the first sealing member receives the edges of the anode porous transport layer, the anode electrode layer, the membrane, the cathode electrode layer and the cathode porous transport layer in the direction perpendicular to the stacking direction therein, so as to maintain the anode porous transport layer, the anode electrode layer, the membrane, the cathode electrode layer and the cathode porous transport layer as an integrated structure.

4. The electrolysis unit according to claim 1 , wherein:the stack and the first sealing member are respectively sandwiched between the first electrode plate and the second electrode plate in the stacking direction; and / orthe first sealing member isolates the second sealing member from the stack; and / or the electrolysis unit further comprises an electrolyte inlet manifold channel (20c), an anodeside outlet manifold channel (20a), and a cathode-side outlet manifold channel (20b), each of the electrolyte inlet manifold channel, the anode-side outlet manifold channel, and the cathode-side outlet manifold channel extending through the first sealing member along the stacking direction.

5. The electrolysis unit according to claim 1, wherein the electrolysis unit is used to electrolyze water in an alkaline electrolyte, and the first sealing member is made of a sealing material resistant to corrosion by the alkaline electrolyte.

6. The electrolysis unit according to any one of claims 1 to 5, wherein the second sealing member is bonded between the first electrode plate and the second electrode plate to maintain the first electrode plate and the second electrode plate as an integrated structure.

7. The electrolysis unit according to claim 6, wherein the second sealing member is formed of sealant or adhesive film.

8. The electrolysis unit according to claim 6, wherein:the second sealing member is configured to contact the first sealing member in the direction perpendicular to the stacking direction, so as to bond the first sealing member to the first electrode plate and the second electrode plate together; orthe second sealing member is configured to be spaced apart from the first sealing member in the direction perpendicular to the stacking direction.

9. The electrolysis unit according to claim 6, wherein:the first electrode plate comprises a first electrode plate body (21a) and a first electrode frame (21 b) surrounding the first electrode plate body in the direction perpendicular to the stacking direction, the first electrode frame being fixed to the first electrode plate body or integrally formed with the first electrode plate body;the second electrode plate comprises a second electrode plate body (22a) and a second electrode frame (22b) surrounding the second electrode plate body in the direction perpendicular to the stacking direction, the second electrode frame being fixed to the second electrode plate body or integrally formed with the second electrode plate body; andthe first sealing member and the second sealing member are respectively disposed between the first electrode frame and the second electrode frame in the stacking direction.

10. The electrolysis unit according to claim 9, wherein:one or both of the first electrode frame and the second electrode frame comprise a groove (621) recessed therein along the stacking direction, the groove having a narrower entrance portion (621a) and a wider inner portion (621b) in the stacking direction, a portion (40a, 40b) of the second sealing member being disposed in the groove and filling the groove; and / orthe first electrode frame comprises a first body (721a) and at least one first annular protrusion (721b) protruding from the first body toward the second electrode frame along thestacking direction, and the second electrode frame comprises a second body (722a) and at least one second annular protrusion (722b) protruding from the second body toward the first electrode frame along the stacking direction, the at least one first annular protrusion and the at least one second annular protrusion being offset from each other in the stacking direction and alternately arranged in the direction perpendicular to the stacking direction, adjacent first annular protrusions and second annular protrusions being spaced apart from each other in the direction perpendicular to the stacking direction to define a gap therebetween, the second sealing member being disposed in the gap and being disposed between the top of the at least one first annular protrusion and the second body of the second electrode frame and between the top of the at least one second annular protrusion and the first body of the first electrode frame; and / orthe surface of each of the first electrode frame and the second electrode frame opposite to the second sealing member is roughened; and / orthe second sealing member provides an adhesive force of at least 10 N / mm or at least 1 MPa between itself and each of the first electrode plate and the second electrode plate.

11. An electrolysis apparatus (10) comprising:a plurality of electrolysis units (20, 620, 720), each of the plurality of electrolysis units being an electrolysis unit according to any one of claims 1 to 10, and the plurality of electrolysis units being stacked along the stacking direction (28); anda first end plate (51) and a second end plate (52), the first end plate and the second end plate clamping the plurality of electrolysis units therebetween in the stacking direction to hold the plurality of electrolysis units together.

12. The electrolysis apparatus according to claim 11, wherein:the electrolysis apparatus further comprises a hydraulic drive device (55), the first end plate is a fixed end plate, the second end plate is a movable end plate and can be driven by the hydraulic drive device to move relative to the first end plate in the stacking direction; and / or the stacking direction is horizontally oriented relative to the direction of gravity.

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