WATER ELECTROLYSIS MODULE HAVING IMPROVED STACKING STABILITY

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0118732, filed on Sep. 2, 2024, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a water electrolysis module having improved stacking stability.

2. Discussion of Related Art

Electrolysis refers to a technology of producing hydrogen by electrolyzing pure water, can respond to the currently increasing demand for hydrogen and can also be used as a large-capacity power storage technology that stores renewable energy such as wind power and solar energy. Hydrogen has advantages in that it can have high energy density, can be stored stably for a long time, and be stored in various forms such as gas or liquid.

The basic concept of a water electrolysis stack has the same as the production of hydrogen and oxygen through an electrolysis reaction but is classified into alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), anion exchange membrane water electrolysis (AEMWE), and solid oxide electrolysis cell (SOEC) according to an electrolyte that is used. In particular, AEMWE uses an anion exchange membrane as an electrolyte and can reduce the cost of hydrogen production using low-cost catalysts like the AWE. Since this technology can operate effectively even at low power and operate at a high pressure without a compressor, there is a high efficiency and purity.

Various manifolds for supplying or discharging hydrogen, air, and cooling water are formed on upper and lower portions of a water electrolysis stack. Conventional water electrolysis stacks are formed by sequentially stacking various components such as a membrane, a cathode electrode, an anode electrode, a cathode fluid diffusion layer, an anode fluid diffusion layer, a cell frame, a current collector, a gasket, an insulator, an end plate, etc.

Conventional technologies sequentially stack components one by one, and as the number of cells increases, components such as a gasket, a membrane, or the like are more likely to be misaligned with desired positions. This can result in external leakage of gas and fluid and cross leakage of hydrogen and oxygen, and incomplete adhesion between a membrane and an electrode can cause degradation and performance degradation.

SUMMARY OF THE INVENTION

The present invention is directed to providing a water electrolysis module having improved stacking stability.

According to an aspect of the present invention, there is provided a water electrolysis module in which a plurality of water electrolysis stacks are stacked and adjacent water electrolysis stacks are connected without a gap in a stacking direction, wherein each water electrolysis stack in which a current collector, a cathode cell frame, a membrane electrode assembly, and an anode cell frame are sequentially stacked and fastened by a fastening member, wherein the water electrolysis stack has one or more through holes through which the current collector, the cathode cell frame, and the anode cell frame pass, the anode cell frame has a counter bore continued from the through hole and has a greater size than the through hole, and the fastening member includes a head seated on the counter bore, a shaft extending from the head and passing through the through hole, and a hook provided along an outer circumferential surface of one end portion of the shaft and protruding outward from the through hole to provide a compression force in a stacking direction.

The one end portion of the shaft may be branched into a plurality of portions and may have radial elasticity.

A groove may be provided in an upper surface of the head, the thickness of the head may be less than or equal to the depth of the counter bore, a depth of the groove may be greater than or equal to a thickness of the hook, and an area of the groove may be greater than or equal to an area of the hook.

A central portion of the cathode cell frame may be provided with a cathode fluid diffusion layer, and a central portion of the anode cell frame may be provided with an anode fluid diffusion layer, a central portion of the membrane electrode assembly may be held by the cathode fluid diffusion layer and the anode fluid diffusion layer, and an edge portion of the membrane electrode assembly may be held by the cathode cell frame and the anode cell frame.

The cathode cell frame may have a cathode cell frame concave portion which accommodates a cathode cell frame gasket for preventing cross leakage between a cathode electrode and an anode electrode of the membrane electrode assembly, the anode cell frame may have an anode cell frame concave portion which accommodates an anode cell frame gasket for preventing cross leakage between the cathode electrode and the anode electrode of the membrane electrode assembly, and the cathode cell frame gasket may have a protrusion formed to protrude toward the anode cell frame concave portion to surround a side surface of the membrane electrode assembly.

An area of the anode fluid diffusion layer may be greater than an area of the cathode fluid diffusion layer, and a contact area of the anode cell frame and the membrane electrode assembly may be greater than a contact area of the cathode cell frame and the membrane electrode assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The above matters and other objects, features, and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic exploded cross-sectional view illustrating a water electrolysis stack constituting a water electrolysis module according to an embodiment of the present invention;

FIG. 2 is an enlarged view of area A in FIG. 1;

FIG. 3 is a schematic cross-sectional view illustrating the water electrolysis stack constituting a water electrolysis module according to the embodiment of the present invention;

FIG. 4 is a schematic perspective view for describing a fastening member;

FIG. 5 is a schematic cross-sectional view for describing the fastening member;

FIG. 6 is a schematic cross-sectional view for describing a coupling relationship between water electrolysis stacks in a water electrolysis module in which two or more water electrolysis stacks are stacked; and

FIG. 7 is an enlarged view of area B of FIG. 6.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Advantages and features of the present invention and methods for achieving them will become clear by referencing embodiments described below in detail together with the accompanying drawings.

However, the present invention is not limited to embodiments disclosed below but can be implemented in various different forms, these embodiments are merely provided to make the disclosure of the present invention complete and fully inform those skilled in the art to which the present invention pertains of the scope of the present invention, and the present invention is only defined by the scope of the appended claims. The same reference numerals denote the same components throughout the specification.

Accordingly, in some embodiments, well-known process operations, well-known structures, and well-known technologies are not specifically described to avoid ambiguous construction of the present invention.

Terms used in the present specification are intended to describe the embodiments and are not intended to limit the present invention. In the present specification, the singular form also includes the plural form unless specifically stated in a corresponding phrase.

Throughout the specification of the present application, when a certain portion is described as being “connected to” another portion, it includes not only a case in which the certain portion is “directly connected” to another portion, but also a case in which the certain portion is “electrically connected” to another portion with still another portion interposed therebetween. In addition, throughout the present specification, when a certain portion is described as “including” a certain element, it means that the certain portion may further include another element rather than precluding another element unless specifically stated to the contrary.

Hereinafter, exemplary embodiments of the present invention will be described in detail by referencing the accompanying drawings. In this case, it should be noted that the same component in the accompanying drawings is denoted with the same reference numeral as often as possible. Detailed descriptions of well-known functions and components which can obscure the gist of the present invention are omitted. For the same reason, some components in the accompanying drawings are exaggerated, omitted, or schematically illustrated, and the size of each component does not entirely reflect the actual size thereof.

FIG. 1 is a schematic exploded cross-sectional view illustrating a water electrolysis stack constituting a water electrolysis module according to an embodiment of the present invention, FIG. 2 is an enlarged view of area A in FIG. 1, and FIG. 3 is a schematic cross-sectional view illustrating the water electrolysis stack constituting a water electrolysis module according to the embodiment of the present invention.

Referring to FIGS. 1 to 3, the water electrolysis stack according to the embodiment of the present invention includes a current collector 10, a cathode cell frame 20, a membrane electrode assembly 30, and an anode cell frame 40 which are sequentially stacked.

The membrane electrode assembly 30 may include a membrane 32, a cathode electrode 34 formed in close contact with one side of the membrane 32, and an anode electrode 36 formed in close contact with the other side of the membrane 32.

The membrane 32 may be an anion exchange membrane (AEM) but is not limited thereto.

At the cathode electrode 34, as shown in Reaction Formula 1 below, electrons supplied from an external power source react with water (H₂O) to generate hydrogen gas and OH⁻, and the OH⁻ may move to the anode electrode 36 through the membrane 32 to generate water (H₂O) and oxygen gas as shown in Reaction Formula 2 below.

A central portion of the cathode cell frame 20 is provided with a cathode fluid diffusion layer 60 as a reaction surface.

Although not illustrated, a flow path and a plurality of manifolds through which hydrogen may flow are formed in the cathode cell frame 20.

The cathode cell frame 20 has a first cathode cell frame concave portion 24 which accommodates a cathode cell frame gasket 82 for preventing cross leakage between the cathode electrode 34 and the anode electrode 36.

In addition, the cathode cell frame 20 has a second cathode cell frame concave portion 26 which accommodates an external leakage prevention gasket 86 for preventing external leakage due to thermal expansion, relaxation, and the like of different materials in the cathode fluid diffusion layer 60 and the membrane electrode assembly 30 during operation of the water electrolysis stack.

The cathode cell frame 20 is provided with one or more through holes 22 into which a shaft 54 of a fastening member 50 to be described below is inserted.

A central portion of the anode cell frame 40 is provided with an anode fluid diffusion layer 70 as a reaction surface.

Although not illustrated, a flow path and a plurality of manifolds through which circulating water and oxygen may flow are formed in the anode cell frame 40.

The anode cell frame 40 has a first anode cell frame concave portion 44 which accommodates an anode cell frame gasket 84 for preventing cross leakage between the cathode electrode 34 and the anode electrode 36.

In addition, the anode cell frame 40 has a second anode cell frame concave portion 46 which accommodates the external leakage prevention gasket 86 for preventing external leakage due to thermal expansion, relaxation, and the like of different materials in the anode fluid diffusion layer 70 and the membrane electrode assembly 30 during operation of the water electrolysis stack.

The anode cell frame 40 is provided with one or more through holes 42 into which the shaft 54 of the fastening member 50 to be described below is inserted. In addition, the anode cell frame 40 is provided with a counter bore 43 continued from the through hole 42 and has a greater size than the through hole 42 in order to seat a head 52 of the fastening member 50 when the fastening member 50 to be described below is inserted. The through hole 42 provided in the anode cell frame 40 is provided at the same position as the through hole 22 provided in the cathode cell frame 20.

The central portion of the membrane electrode assembly 30 is held by the cathode fluid diffusion layer 60 and the anode fluid diffusion layer 70, and an edge portion of the membrane electrode assembly 30 is held by the cathode cell frame 20 and the anode cell frame 40.

The cathode cell frame gasket 82 has a protrusion formed to protrude toward the first anode cell frame concave portion 44 to surround a side surface of the membrane electrode assembly 30.

When the water electrolysis stack is fastened, the cathode cell frame gasket 82 and the anode cell frame gasket 84 may form a gasket with a separate sealed structure, thereby fundamentally blocking cross leakage to the side surface of the membrane electrode assembly 30.

Adhesion surfaces of the cathode cell frame gasket 82, the anode cell frame gasket 84, and the external leakage prevention gasket 86, which are sealed when the water electrolysis stack is fastened, may form two or more contact surfaces, thereby effectively preventing hydrogen and oxygen from leaking out of the water electrolysis stack.

The current collector 10 serves to move a current generated from an electrode to a separator.

Although not illustrated, the current collector 10 has a plurality of manifolds formed at the same positions as the cathode cell frame 20 and the anode cell frame 40, and reaction surfaces are not present.

The current collector 10 is provided with one or more through holes 12 into which the shaft 54 of the fastening member 50 to be described below is inserted.

The through holes 12 provided in the current collector 10 are provided at the same positions as the through holes 42 provided in the anode cell frame 40 and the through holes 22 provided in the cathode cell frame 20.

Referring to FIG. 3, an area of the anode fluid diffusion layer 70 may be greater than an area of the cathode fluid diffusion layer 60, and a contact area between the anode cell frame 40 and the membrane electrode assembly 30 may be greater than a contact area between the cathode cell frame 20 and the membrane electrode assembly 30. That is, an area of a protruding portion (hereinafter referred to as an anode-side sealing portion support 48) inside the first anode cell frame concave portion 44 in the anode cell frame 40 may be smaller than an area of a protruding portion (hereinafter referred to as a cathode-side sealing portion support 28) inside the first cathode cell frame concave portion 24 in the cathode cell frame 20.

In general, a gap of 0.05 to 0.2 mm is present between the anode electrode 36, the anode fluid diffusion layer 70, and the anode-side sealing portion support 48, and this gap may cause deformation of a membrane due to a difference in pressure between a cathode side of a high-pressure part and an anode side of a low-pressure part. However, in the present invention, since the cathode-side sealing portion support 28 of the high-pressure part is positioned inward further than the anode-side sealing portion support 48 of the low-pressure part and has a structure which overlaps the gap between the anode fluid diffusion layer 70 and the anode-side sealing portion support 48, a part of a membrane deformation-vulnerable portion can be supported by the cathode-side sealing portion support 28 of the high-pressure part, thereby preventing deformation of the membrane.

FIGS. 4 and 5 are a schematic perspective view and cross-sectional view, respectively, for describing the fastening member 50.

Referring to FIGS. 4 and 5, the fastening member 50 includes the head 52, the shaft 54 extending from the head 52, and a hook 56 provided along an outer circumferential surface of one end portion of the shaft 54.

A material of the fastening member 50 is not particularly limited, and for example, plastic engineering materials such as polyetheretherketone (PEEK), polypropylene (PP), polyethylene (PE), polyphenylene sulfide (PPS) GF 40, or the like may be used.

A groove 58 is provided in an upper surface of the head 52 of the fastening member 50 and formed to accommodate the hook protruding outward from the current collector of the water electrolysis stack positioned thereon when the water electrolysis stack is stacked so that a plurality of water electrolysis stacks are stacked without any spacing.

The shaft 54 of the fastening member 50 has a cylindrical shape having an empty interior, and the one end portion of the shaft 54 is branched into a plurality of portions and has radial elasticity. Accordingly, a lower end of the shaft 54 on which the hook 56 is formed has elasticity so that the lower end can be closed inward or opened outward. For reference, FIGS. 4 and 5 illustrate the shaft 54 having a cylindrical shape, but the present invention is not limited thereto, and the shaft 54 may have any of various shapes of cross sections such as a square, rectangle, oval, etc.

When the water electrolysis stack is fastened, the hook 56 of the fastening member 50 passes through the through hole 42 while closed inward and becomes caught onto the current collector 10 while protruding outward from the through hole 42 and re-opened outward due to elasticity to provide a compression force in a stacking direction of the water electrolysis stack.

When the water electrolysis stack is disassembled, disassembly can be easily performed by an external force applied upward in a state in which the hook 56 of the fastening member 50 is closed inward.

FIG. 6 is a schematic cross-sectional view for describing a coupling relationship between water electrolysis stacks in a water electrolysis module in which two or more water electrolysis stacks are stacked, and FIG. 7 is an enlarged view of area B in FIG. 6.

The groove 58 is provided in the upper surface of the head 52 of the fastening member 50 and formed to accommodate the hook protruding outward from the current collector of the water electrolysis stack positioned thereon when the water electrolysis stack is stacked so that a plurality of water electrolysis stacks are stacked without any spacing. To this end, a thickness of the head is less than or equal to the depth of the counter bore, a depth d₁ of the groove 58 is formed to be greater than or equal to a thickness d₂ of the hook 56, and an area of the groove 58 is formed to be greater than or equal to an area of the hook 56.

In particular, when the shapes and sizes of the hook 56 and the groove 58 are the same, components can be accurately aligned without any step therebetween, and thus there is an advantage that the water electrolysis stack can be easily applied to a large-capacity water electrolysis system modularized by connecting tens to hundreds of electrolytic stacks.

A water electrolysis module according to an aspect of the present invention can have excellent durability by preventing components from being misaligned with desired positions.

In addition, it is possible to improve adhesion between a membrane and an electrode, thereby preventing degradation of a stack and improving performance.

Moreover, since components can be accurately aligned without any step therebetween, the water electrolysis stack can be easily applied to a large-capacity water electrolysis system modularized by connecting tens to hundreds of water electrolysis stacks.

It should be understood that the effects of an aspect of the present invention are not limited to the above effects and include all effects inferable from the configuration described in the detailed description or claims of the invention of the present specification.

Although exemplary embodiments of the present invention have been described above, the scope of the present invention is not limited to only these specific embodiments, and those skilled in the art who understand the spirit of the present invention can easily propose other embodiments by adding, changing, and omitting a component within the obvious scope, but they should be construed as also belonging to the scope of the claims of the present invention.

The scope of the present specification is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts thereof should be construed as being included in the scope of the present specification.