Electrolysis cell, electrolysis block comprising a plurality of corresponding electrolysis cells, and electrolysis device comprising a plurality of electrolysis cells

Abstract

The invention relates to an electrolysis cell (1) for alkaline hydrogen electrolysis, comprising an electric anode (2), an electric cathode (3), a separation layer (4) which is substantially permeable to ions, is electrically insulating, is preferably in the form of a membrane or a diaphragm and is placed between the anode (2) and the cathode (3), and two electrically conductive half-shells (5, 5') which are electrically insulatingly connected to one another at their edges, wherein: the anode (2) is electrically conductingly connected to the first half-shell (5), and the cathode (3) is electrically conductingly connected to the second half-shell (5'); the anode (2), the cathode (3) and the separation layer (4) are placed between the two half-shells (5, 5') such that an anode chamber (6) and a cathode chamber (7) are formed; each of the half-shells comprises at least one inflow pipe (8, 8') and at least one outflow pipe (9, 9') for a medium; and each of the half-shells (5, 5') comprises a metal support frame (10, 10') for absorbing compressive forces, and a substantially flat outer skin (11, 11'), the support frame (10, 10') and outer skin (11, 11') being integrally bonded together, preferably welded together.

Description

[0001] 1 Andritz AG, Stattegger Strasse 18, 8045 Graz (AT)

[0002] Electrolysis cell and electrolysis device with an electrolysis cell

[0003] The invention relates to an electrolysis cell and an electrolysis device for producing hydrogen.

[0004] Various processes for producing hydrogen (H2) are known in the art. For example, hydrogen can be extracted from natural gas / methane, resulting in so-called blue or gray hydrogen. However, processes like these require hydrocarbons as the starting material.

[0005] A more environmentally friendly variant of hydrogen production is electrolysis from water and the use of electricity from renewable energy sources. This production process produces so-called green hydrogen and is particularly advantageous because hydrogen production offers a way to store excess electricity, for example, from wind power.

[0006] Hydrogen production through electrolysis has long been known in the state of the art. In industry, the alkaline electrolysis process and electrolysis using a proton exchange membrane are particularly used.

[0007] State-of-the-art alkaline electrolyzers are mostly systems that operate under atmospheric pressure or slight overpressure up to 1 bar. Such systems are often designed as interconnected individual cells to facilitate transport and assembly of the electrolyzer. The medium supply, often a potassium hydroxide solution (KOH) in the case of an alkaline electrolyzer, is handled separately for each individual cell. The removal of product and excess KOH is also handled separately for each individual cell. The problem with a process under such conditions is that the hydrogen must be compressed for further processing or transport. Systems operating under atmospheric conditions therefore require an additional compressor. The disadvantage of these compressors, however, is their high maintenance intensity and the resulting additional costs.

[0008] Alkaline electrolyzers can also be designed as pressurized systems. In these cases, they are typically operated at up to 30 bar. Pressurized electrolyzers are designed as integrated multi-cell stacks, meaning that the distribution of the alkali and the removal of the product take place within the cells. The disadvantage of pressurized systems is that they are difficult to transport and assemble. Such systems weigh up to 90 tons. This design also complicates the mass production of pressurized systems.

[0009] The object of the present invention is to overcome the problems of the prior art and to provide a pressurized electrolyzer comprising individual cells whose transport, assembly, and / or maintenance are as simple as possible. A further object of the invention can be seen in providing the most powerful system possible with minimal material consumption and enabling the simplest possible serial production of the components for a pressurized electrolysis device.

[0010] These and other objects are achieved by an electrolysis cell according to claim 1. An electrolysis cell according to the invention for alkaline hydrogen electrolysis comprises an electrical anode, an electrical cathode, and a substantially ion-permeable and electrically insulating separating layer, preferably designed as a membrane or diaphragm, which is arranged between the anode and the cathode. The electrolysis cell comprises two electrically conductive half-shells which are electrically insulatingly connected to one another at their edges, wherein the anode is electrically conductively connected to the first half-shell and the cathode is electrically conductively connected to the second half-shell, and wherein the anode, the cathode, and the separating layer are arranged between the two half-shells, so that an anode compartment and a cathode compartment are formed, and wherein the half-shells each comprise at least one supply line and at least one discharge line for a medium.

[0011] Alkaline hydrogen electrolysis can involve electrolysis using aqueous potassium hydroxide (KOH) or aqueous sodium hydroxide (NaOH) as the medium. The medium thus includes the alkalis KOH and NaOH, the gases H2 and O2, and mixtures of these substances.

[0012] The electrolysis cell is preferably designed as a zero-gap system. The zero-gap system allows direct contact of the electrodes (cathode and anode) with the separation layer, thereby achieving a higher current density (up to 1 kA / m 2 ) is possible than with cells where the electrodes are spaced further apart. This design allows for a compact design and minimizes overvoltages.

[0013] The ion-permeable separating layer is electrically insulating to prevent short circuits between the electrodes. The separating layer is preferably 0.05 mm to 0.5 mm thick and permeable. The separating layer can be designed as a permeable membrane or a diaphragm. Ion permeability is provided by alkali penetrating the separating layer. Due to the polarity of the material, gas cannot diffuse through the separating layer, as the separating layer essentially repels nonpolar compounds such as H2 and O2. OH' ions can, however, diffuse through the separating layer. For example, a polyphenylene sulfide fabric coated with a mixture of a polymer (e.g., polysulfone) and zirconium oxide (ZrCh) can be used as the separating layer.

[0014] The half-shells of the electrolysis cell are connected to one another, preferably by screwing the half-shells together. The half-shells are essentially designed such that, by applying a direct voltage of at least 1.23 volts, H2 and OH' are formed in the cathode compartment and O2 and H2O are formed in the anode compartment. OH' can then diffuse through the separating layer into the anode compartment, allowing O2 and H2O to be formed again. Preferably, a voltage of 1.48 volts or more is used between the anode and cathode for an individual cell during operation.

[0015] According to the invention, the half-shells each have a solid, circumferential metallic support frame at their edges to absorb compressive forces. The support frame encompasses a large, essentially flat, metallic outer skin of the half-shells. The support frame and the outer skin are integrally connected, preferably welded.

[0016] The metallic support frame can be made of steel, steel with nickel coatings, or nickel, preferably stainless steel. The metallic outer skin can be made of nickel, suitable stainless steel, or a nickel alloy.

[0017] In general, all components of the electrolysis cell can be substantially alkali-resistant, hydrogen-resistant, oxygen-resistant, and water-resistant. The electrolysis cell according to the invention is preferably substantially gas-tight and liquid-tight.

[0018] Optionally, the outer skin of the electrolysis cell is designed as an alkali-resistant, metallic foil with a thickness of approximately 0.1 mm, preferably approximately 0.05 mm. Such a thin outer skin allows for lower material consumption and a lower overall weight of the electrolysis cell without limiting the functionality of the electrolysis cell. Optionally, the outer skin of the electrolysis cell comprises or consists of alkali-resistant stainless steel, nickel, or a nickel alloy. This embodiment has proven advantageous in practice, as it fulfills the necessary technical requirements for operating the electrolysis cell.

[0019] Where appropriate, the support frame is designed to be essentially annular and the outer skin essentially circular. However, the support frame can also be square or rectangular. However, to better absorb radial compressive forces, an annular support frame is preferred, especially for larger dimensions.

[0020] Optionally, a stabilizing, electrically conductive support structure, preferably comprising a metal grid, is arranged in the anode and cathode compartments of the electrolysis cell. The support structure facilitates the assembly of the electrolysis cell and has a stabilizing effect during operation. The support structure can be designed as a lattice-like support structure, for example, comprising individual or interconnected struts.

[0021] Where appropriate, the half-shells are connected exclusively via the support frames, so that the two outer skins of the half-shells do not touch each other. A circumferential plastic seal is provided for electrical insulation and to seal the support frames. Preferably, several screw connections are provided to connect the support frames.

[0022] Optionally, the support frame is approximately 100 to approximately 200 times thicker than the outer skin, preferably having a thickness of approximately 1 cm to approximately 2 cm. The depth of the support frame can be approximately 5 cm to approximately 20 cm. This creates a stable support frame capable of absorbing radial compressive forces prevailing inside the half-shells.

[0023] Where appropriate, the half-shells are intended to have a diameter of approximately 1 m to approximately 3 m and a thickness of approximately 1 cm to approximately 3 cm, so that the electrolysis cell has a thickness of approximately 2 cm to approximately 6 cm. This ensures the stability of the electrolysis cell, while keeping material costs low and achieving a relatively low weight of approximately 150 kg to 250 kg for a single electrolysis cell with an active area of ​​several m 2 is accessible.

[0024] Where appropriate, the anode electrode may comprise nickel or a nickel alloy, with or without a coating.

[0025] Where appropriate, the cathode electrode may comprise nickel or a nickel alloy, with or without a coating.

[0026] The coatings can include both non-noble metals or minerals, as well as precious metals such as platinum, ruthenium, or indium. Generally, the electrodes can be porous, allowing for better control over the reaction distribution and transport of substances.

[0027] Optionally, the supply and discharge lines are each designed as bores in the support frame. This design is advantageous because it allows for a simple design for the supply and discharge of media. Optionally, the half-shells are each provided with their own supply lines and separately arranged discharge lines. This design allows for the H2 and O2 gases to be removed separately from the residual liquor.

[0028] Optionally, the medium is a potassium hydroxide solution (KOH) under a pressure of more than 10 bar, preferably approximately 30 bar. This embodiment is advantageous because it eliminates the need to compress the product gases H2 and O2 after their production for further use.

[0029] Optionally, at least one of the support frames can be constructed in multiple parts, wherein the parts of the support frame are preferably constructed to overlap so that an obliquely overlapping connection of the parts can be achieved. The invention further relates to an electrolysis block for alkaline hydrogen electrolysis, comprising a plurality of electrolysis cells according to the invention, wherein the outer skin of the cathode compartment of each electrolysis cell is arranged flush with the outer skin of the anode compartment of an adjacent electrolysis cell and is electrically conductive, and wherein the electrolysis cells are held together by connecting means, in particular screw connections. The connecting means can preferably run entirely through the support frames and press them together. Optionally, the screw connections can be designed to hold together the support frames of a plurality of, preferably up to approximately 100, serially arranged electrolysis cells.Accordingly, an electrolysis block can comprise up to about 100, possibly even up to 200 or more, electrolysis cells.

[0030] The use of such prefabricated electrolysis blocks facilitates the construction and handling of an electrolyzer, as the electrolysis blocks can be transported individually and only need to be assembled on site. A single electrolysis block can weigh up to approximately 10 t. Furthermore, testing prefabricated electrolysis blocks is significantly easier than testing individual electrolysis cells, especially when using electrolysis cells with very thin outer skins. It also enables the series production of electrolysis blocks with a predetermined number of electrolysis cells, such as 20, 50, 100, or 200 electrolysis cells. Furthermore, the size and weight of the electrolysis blocks can be adapted to the capabilities of the available transport and lifting equipment, such as trucks and forklifts, by adjusting the number of electrolysis cells.

[0031] If necessary, the two support frames arranged at the front of the electrolysis block can be designed with recesses to flush-mount the end pieces of the connecting elements, in particular screw nuts. These would otherwise protrude beyond the outer surface of the front sides of the electrolysis block.

[0032] Optionally, electrically conductive adapter plates with recesses can also be provided on the two end faces of the electrolysis block to flushly accommodate the end pieces of the connecting means, in particular the screw nuts. The invention further relates to an electrolyzer for alkaline hydrogen electrolysis, comprising a plurality of electrolysis cells according to the invention arranged serially and preferably horizontally between a positive electrical pole and a negative electrical pole. In an electrolyzer according to the invention, the outer skin of the cathode compartment of each individual electrolysis cell is arranged flush with the outer skin of the anode compartment of another electrolysis cell and is electrically conductive.

[0033] In such a serial arrangement of the electrolysis cells, they are mechanically connected via their support frames, while the thin outer skins of the half-shells fit closely together, thus ensuring excellent electrical contact with very low electrical resistance.

[0034] Preferably, approximately 100 to 200 electrolysis cells can be arranged in series, although up to 400 electrolysis cells can also be arranged in series. A direct voltage of approximately 1.5 to 2.5 volts per cell is applied between the positive and negative electrical poles.

[0035] An electrolyzer according to the invention can also have at least one, optionally several, electrolysis blocks according to the invention arranged in series between an electrical positive pole and an electrical negative pole, preferably horizontally.

[0036] The electrolysis cells and electrolyzer are designed so that the electrolyzer can be operated at a pressure of approximately 30 bar and higher, approximately 60 bar. In this case, a pressure of approximately 30 bar or higher prevails in each electrolysis cell. However, this does not lead to the bursting of the thin outer skin, as each outer skin is in full contact with the outer skin of a neighboring electrolysis cell or an end plate. Consequently, the electrolysis cells can be subjected to very high pressure, even though the outer skins of the electrolysis cells are very thin.

[0037] Optionally, the electrolysis cells and / or electrolysis blocks are arranged between two end plates, wherein the end plates are firmly clamped by preferably several tie rods, and wherein insulating elements are arranged between the end plates and the poles. The tie rods are designed to exert a high mechanical tensile stress on the end plates in order to counteract the gas pressure prevailing inside the electrolysis cells.

[0038] If necessary, separately adjustable supply lines and separately adjustable discharge lines are provided for each electrolysis cell and / or electrolysis block, so that the supply and discharge of medium can be regulated separately for each electrolysis cell and / or electrolysis block. This embodiment is advantageous because it makes the system easier to maintain. For example, a single electrolysis cell can be replaced without having to dismantle and disassemble the entire electrolyzer.

[0039] If necessary, the supply and discharge lines of the electrolysis cells are connected to common pressure manifolds. This design has proven advantageous in practice.

[0040] The invention will now be explained in more detail using non-exclusive embodiments. They show:

[0041] Figure 1 a shows a schematic cross-sectional view of an electrolysis cell according to the invention;

[0042] Figure 1b shows a schematic front view of an electrolysis cell according to the invention; Figures 2 and 3a - 3d show schematic cross-sectional views of electrolyzers according to the invention.

[0043] Figures 1a and 1b show a schematic cross-sectional representation and a front view of an electrolysis cell 1 according to the invention for alkaline hydrogen electrolysis. Such an electrolysis cell 1 can be manufactured individually and thus in series. The materials and components used are essentially alkali-resistant, oxygen-resistant, and hydrogen-resistant. The electrolysis cell 1 is also designed to be liquid-tight and gas-tight. The electrolysis cell 1 comprises an electrical anode 2, at which O2 and H2O are formed, and an electrical cathode 3, at which H2 and OH' are formed. Between the two electrodes, an electrically insulating separating layer 4 in the form of a membrane is arranged, which, however, is ion-permeable, allowing OH' ions to diffuse through the separating layer 4 and forming a closed circuit.The anode 2, the separating layer 4, and the cathode 3 are arranged directly next to each other, creating a so-called zero-gap arrangement. The anode 2 and the cathode 3 are not in contact with each other.

[0044] In this embodiment, the separating layer 4 consists of a polyphenylene sulfide fabric containing a mixture of polysulfone and zirconium oxide (ZrO2), as well as optionally polytetrafluoroethylene and inorganic additives. It is 0.5 mm thick and has a porosity of, for example, 55%. The anode 2 is made of nickel, but can also be made of other materials. The cathode 3 is made of nickel, but can also be made of other materials.

[0045] The electrolysis cell 1 comprises two electrically conductive half-shells 5, 5', which are screwed together at their edges in an electrically insulating manner. The half-shells 5, 5' each comprise a support frame 10, 10' made of stainless steel and a flat outer skin 11, 1T made of a nickel alloy, which are welded together. The support frame 10, 10' is annular and the outer skin 11, 1T is circular. The support frame 10, 10' has a thickness of approximately 1.5 cm and a depth of approximately 10 cm. The outer skin 11, 1T has a thickness of approximately 0.075 mm. The annular support frame 10, 10' and the circular outer skin 11, 1T have a diameter of approximately 2 m. With these dimensions, the electrolysis cell 1 weighs approximately 150 kg.

[0046] The anode 2 is electrically connected to the first half-shell 5, while the cathode 3 is electrically connected to the second half-shell 5'. The anode 2 together with the first half-shell 5 is separated from the cathode 3 together with the second half-shell 5' by the separating layer 4, so that an anode chamber 6 and a cathode chamber 7 are formed. An electrically insulating plastic seal 13 is also arranged between the two half-shells 5, 5'. Bores are provided in the support frame 10, 10' of the half-shells 5, 5', which are suitable for the supply lines 8, 8' and discharge lines 9, 9' for a medium, wherein the supplied medium in this embodiment is a KOH solution with a concentration between 20% and 40%. The medium discharged from the anode chamber is a mixture of O2 and KOH solution. The medium derived from the cathode compartment 7 is a mixture of H2 and KOH solution.

[0047] In this embodiment, a support structure 12, 12' is arranged in the anode chamber 6 and in the cathode chamber 7, which is designed as lattice-like struts made of nickel, stainless steel or other materials.

[0048] Figure 2 shows a schematic cross-sectional view of an electrolyzer according to the invention. The electrolyzer comprises approximately 200 electrolysis cells 1 arranged in series between a positive electrical pole 14 and a negative electrical pole 15 according to the exemplary embodiment of Figures 1a and 1b. The outer skin 11, 1T of the cathode compartment 7 of each electrolysis cell 1 is arranged flush and electrically conductively on the outer skin 11, 1T of the anode compartment 6 of an adjacent electrolysis cell.

[0049] The serially arranged electrolysis cells 1 are clamped between two end plates 17, with insulating elements 16 arranged between the end plates 17 and the positive pole 14 and the negative pole 15. The end plates 17 are connected to one another by tie rods (not shown) and are firmly clamped together.

[0050] Each electrolysis cell 1 has separately adjustable supply lines 8, 8' and discharge lines 9, 9', allowing the supply and discharge of medium to be regulated for each individual electrolysis cell. The supply lines 8, 8' and discharge lines 9, 9' are connected by common pressure manifolds (not shown).

[0051] The electrolyzer according to the invention of the exemplary embodiment can be operated as follows: KOH solution can be introduced into the electrolysis cells 1 through the supply lines 8, 8', and a pressure of up to 30 bar and more can be built up in the interior of the electrolysis cells 1 by hydraulic compression. Alternatively, the pressure within the electrolysis cells can also be built up by the controlled retention of the product gases. The pressure is always the same in the anode chamber 6 and the cathode chamber 7 of the individual electrolysis cells 1. The support frame 10, 10' is designed to absorb any resulting radial compressive forces.

[0052] The end plates 17, which are clamped with tension rods, absorb compressive forces acting axially on the electrolysis cells 1, so that despite the thin outer skin 11, 11' of the individual electrolysis cells 1, a high pressure can be applied.

[0053] Subsequently, a direct voltage of 1.5 to 2.5 volts per cell is applied between the positive pole 14 and the negative pole 15, initiating electrolysis. O2 and H2O are formed at the anode 2, and H2 and OH' at the cathode 3. Between the two electrodes, OH' ions can diffuse through the separating layer 4 from the cathode compartment 7 into the anode compartment 6.

[0054] The product gases H2 and O2 can be introduced from the individual electrolysis cells 1 into pressure collection lines through discharge lines 9, 9', which are provided in the upper area of ​​the support frames 10, 10', and can be fed to separators for the separation of the lye and H2 or O2.

[0055] Figure 3a shows a schematic cross-sectional view of an electrolysis block 23 according to the invention for alkaline hydrogen electrolysis. The electrolysis block 23 comprises a plurality of electrolysis cells 1 as shown in Figures 1a and 1b. The outer skin 1T of the cathode compartment 7 of each electrolysis cell 1 is arranged flush with the outer skin 11 of the anode compartment 6 of an adjacent electrolysis cell 1 in an electrically conductive manner, resulting in a serial and sandwich-like arrangement of the electrolysis cells 1. The electrolysis cells 1 are held together by connecting means, in particular screw connections 18, 18'. In the present example, two screw connections 18, 18' are provided, but more than two connecting means can also be provided. The connecting means run entirely through the support frames 10, 10' and press them firmly together, resulting in good electrical contact between the electrolysis cells 1.The two front-mounted support frames 10, 10' are designed with recesses 20, 20' to flush-fit the end pieces of the connecting elements, namely the screw nuts 19, 19'. This allows several electrolysis blocks 23 to be arranged in series with good electrical contact.

[0056] Figure 3b shows another schematic cross-sectional view of an electrolysis block 23 according to the invention for alkaline hydrogen electrolysis. The exemplary embodiment corresponds to that of Fig. 3a, with the difference that electrically conductive adapter plates 21, 21' with recesses 22, 22' are provided on the two end faces of the electrolysis block 23 to flush-fit the end pieces of the connecting means, namely the screw nuts 19, 19'. This allows several electrolysis blocks 23 to be arranged in series with good electrical contact.

[0057] Figures 3c and 3d show schematic cross-sectional representations of electrolyzers according to the invention using a plurality of electrolysis blocks 23 according to the invention. The electrolyzers correspond to the basic structure shown in Figure 2 and comprise a plurality of electrolysis blocks 23 arranged serially and horizontally between an electrical positive pole 14 and an electrical negative pole 15. The outer surfaces of adjacent electrolysis blocks 23 are arranged flush and electrically conductively, thus ensuring good and full-surface electrical contact. In the embodiment of Figure 3c, a plurality of electrolysis blocks 23 designed according to Figure 3a are arranged in series with one another. In the embodiment of Figure 3d, a plurality of electrolysis blocks 23 designed according to Figure 3b are arranged in series with one another. The electrolysis blocks 23 are arranged between two solid end plates 17, wherein the end plates 17 are firmly clamped by a plurality of tie rods (not shown).Insulating elements 16 are arranged between the end plates 17 and the poles 14, 15. However, the invention is not limited to the described embodiments, but encompasses all devices and methods within the scope of the following patent claims. List of reference symbols.

[0058] 1 electrolysis cell

[0059] 2 anode

[0060] 3 Cathode

[0061] 4 Separating layer

[0062] 5.5' half shell

[0063] 6 Anode compartment

[0064] 7 Cathode compartment

[0065] 8, 8' supply line

[0066] 9, 9' derivative

[0067] 10.10" support frame

[0068] 11 , 11“ outer skin

[0069] 12, 12" support structure

[0070] 13 Plastic seal

[0071] 14 positive pole

[0072] 15 Negative pole

[0073] 16 Insulating element

[0074] 17 end plates

[0075] 18, 18" screw connection

[0076] 19, 19" screw nut

[0077] 20, 20" recess

[0078] 21 , 21“ adapter plate

[0079] 22, 22" recess

[0080] 23 Electrolysis block

Claims

Patent claims 1. Electrolysis cell (1) for alkaline hydrogen electrolysis, comprising: - an electrical anode (2), an electrical cathode (3) and a substantially ion-permeable and electrically insulating separating layer (4), preferably designed as a membrane or diaphragm, which is arranged between the anode (2) and the cathode (3), - two electrically conductive half-shells (5, 5') which are electrically insulated from one another at their edges, - wherein the anode (2) is electrically conductively connected to the first half-shell (5), and the cathode (3) is electrically conductively connected to the second half-shell (5'), and - wherein the anode (2), the cathode (3) and the separating layer (4) are arranged between the two half-shells (5, 5') so that an anode chamber (6) and a cathode chamber (7) are formed, and - wherein the half-shells (5, 5') each comprise at least one supply line (8, 8') and at least one discharge line (9, 9') for a medium, characterized in that - the half-shells (5, 5') each comprise a circumferential, solid metallic support frame (10, 10') at their edges to absorb compressive forces, - wherein the support frames (10, 10') each enclose a large-area, substantially flat, metallic outer skin (11, 1 T), and - wherein the support frame (10, 10') and the outer skin (11, 1 T) are integrally connected, preferably welded.

2. Electrolysis cell (1) according to claim 1, characterized in that the outer skin (11, 1 T) is designed as an alkali-resistant, metallic foil with a thickness of approximately 0.1 mm, preferably approximately 0.05 mm.

3. Electrolysis cell (1) according to claim 1 or 2, characterized in that the outer skin (11, 1T) comprises or consists of an alkali-resistant stainless steel, nickel or a nickel alloy.

4. Electrolysis cell (1) according to one of claims 1 to 3, characterized in that the support frame (10, 10') is substantially annular and the outer skin (11, 1T) is substantially circular.

5. Electrolysis cell (1) according to one of claims 1 to 4, characterized in that a stabilizing, electrically conductive support structure (12, 12'), preferably comprising a metal grid, is arranged in the anode compartment (6) and in the cathode compartment (7).

6. Electrolysis cell (1) according to one of claims 1 to 5, characterized in that the half-shells (5, 5') are connected only via the support frames (10, 10'), wherein a circumferential plastic seal (13) is provided for electrical insulation between the support frames (10, 10').

7. Electrolysis cell (1) according to one of claims 1 to 6, characterized in that the support frame (10, 10') is thicker than the outer skin (11, 1 T) by a factor of about 100 to about 200 and preferably has a thickness of about 1 cm.

8. Electrolysis cell (1) according to one of claims 1 to 7, characterized in that the half-shells (5, 5') have a thickness of about 1 cm to about 3 cm, so that the electrolysis cell (1) has a thickness of about 2 cm to about 6 cm.

9. Electrolysis cell (1) according to one of claims 1 to 8, characterized in that the half-shells (5, 5') have a diameter of about 1 m to about 3 m.

10. Electrolysis cell (1) according to one of claims 1 to 9, characterized in that the anode (2) comprises nickel or a nickel alloy, with or without a coating.

11. Electrolysis cell (1) according to one of claims 1 to 10, characterized in that the cathode (3) comprises nickel or a nickel alloy, with or without a coating.

12. Electrolysis cell (1) according to one of claims 1 to 11, characterized in that the supply line (8, 8') and the discharge line (9, 9') are each designed as bores in the support frame (10, 10').

13. Electrolysis cell (1) according to one of claims 1 to 12, characterized in that the half-shells (5, 5') each have a separate supply line (8, 8') per cell and separately arranged discharge lines (9, 9') per cell.

14. Electrolysis cell (1) according to one of claims 1 to 13, characterized in that the medium is a potassium hydroxide solution (KOH) or sodium hydroxide solution (NaOH) which is under a pressure of more than 10 bar, preferably about 30 bar.

15. Electrolysis cell (1) according to one of claims 1 to 14, characterized in that at least one of the support frames (10, 10') is designed in several parts, wherein the parts of the support frame (10, 10') are preferably designed to overlap.

16. Electrolysis block (23) for alkaline hydrogen electrolysis, comprising a plurality of electrolysis cells (1) according to one of claims 1 to 15, wherein the outer skin (11') of the cathode compartment (7) of each electrolysis cell (1) is arranged flush with the outer skin (11) of the anode compartment (6) of an adjacent electrolysis cell (1) and in an electrically conductive manner, and wherein the electrolysis cells (1) are held together by connecting means, in particular screw connections (18, 18'), wherein the connecting means preferably run entirely through the support frames (10, 10') and press them together.

17. Electrolysis block (23) according to claim 16, characterized in that the screw connections (18, 18') are designed to hold together the support frames (10, 10') of several, preferably up to about 100, serially arranged electrolysis cells (1).

18. Electrolysis block (23) according to claim 16 or 17, characterized in that the two end-side support frames (10, 10') of the electrolysis block (23) are formed with recesses (20, 20') in order to receive end pieces of the Fasteners, in particular screw nuts (19, 19'), to be accommodated flush.

19. Electrolysis block (23) according to claim 16 or 17, characterized in that on the two end faces of the electrolysis block (23) electrically conductive adapter plates (21, 21') with recesses (22, 22') are provided in order to receive end pieces of the connecting means, in particular screw nuts (19, 19'), flush.

20. Electrolyzer for alkaline hydrogen electrolysis, comprising a plurality of electrolysis cells (1) according to one of claims 1 to 15, arranged serially and preferably horizontally between an electrical positive pole (14) and an electrical negative pole (15), wherein the outer skin (11') of the cathode compartment (7) of each electrolysis cell (1) is arranged flush and electrically conductively with the outer skin (11) of the anode compartment (6) of a further electrolysis cell (1).

21. An electrolyzer for alkaline hydrogen electrolysis, comprising at least one, optionally several, electrolysis blocks (23) according to one of claims 16 to 19, arranged serially between an electrical positive pole (14) and an electrical negative pole (15), preferably horizontally.

22. Electrolyzer according to claim 20 or 21, characterized in that the electrolysis cells (1) and / or the electrolysis blocks (23) are arranged between two end plates (17), wherein the end plates (17) are firmly clamped by preferably several tie rods, and wherein insulating elements (16) are arranged between the end plates (17) and the poles (14, 15).

23. Electrolyzer according to one of claims 20 to 22, characterized in that separately adjustable supply lines (8, 8') and separately adjustable discharge lines (9, 9') are provided for each electrolysis cell (1) and / or for each electrolysis block (23), so that the supply and discharge of medium for each electrolysis cell (1) and / or each electrolysis block (23) can be regulated separately.

24. Electrolyzer according to one of claims 20 to 23, characterized in that the supply lines (8, 8') and discharge lines (9, 9') are connected to common pressure collecting lines.

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