ELECTROLYSIS DEVICE

Description

field of technology

[0001] The present invention is based on an electrolysis device. State of the art

[0002] Electrolysis devices are known in various designs. Generally speaking, an electrolysis device comprises a number of electrolysis units. The number can be one or more. The electrolysis units each comprise a first and a second end plate. The electrolysis units often further comprise an intermediate plate arranged between the first and second end plates, sometimes also several intermediate plates. One of the intermediate plates can be arranged midway between the two end plates.

[0003] The electrolysis units each have a stack of electrolysis cells between two plates - these can alternatively be the two end plates, an end plate and an intermediate plate, or two intermediate plates - with the electrolysis cells of the respective stack being electrically connected in series. The electrolysis cells each have a first electrode and a second electrode at which an electrolysis liquid is electrolytically split, so that after the electrolytic splitting, the electrolysis liquid is mixed with a first electrolysis gas in the region of the respective first electrode and with a second electrolysis gas in the region of the respective second electrode. The electrolysis device also has a rectifier unit which provides a first potential via a first output and a second potential via a second output.

[0004] Several such electrolysis devices are known from US 2010 / 0 012 503 A1. The electrolysis devices known from US 2010 / 0 012 503 A1 each have a single electrolysis unit. In one of these electrolysis devices (hereinafter: prior art 1), the first end plate is connected to the first outlet, the second end plate to the second outlet. An intermediate plate, which in turn is grounded, is arranged between the two end plates. In another of these electrolysis devices (hereinafter: prior art 2), an intermediate plate is also present. The intermediate plate is connected to the first outlet. The two end plates are connected to the second outlet and grounded. In yet another of these electrolysis devices (hereinafter: prior art 3), the two end plates are connected to the first outlet.An intermediate plate is arranged between the two end plates, which is connected to the second output and grounded. In yet another of these electrolysis devices (hereinafter: prior art 4), in addition to the two end plates, a total of three intermediate plates are present. The two end plates and the middle of the three intermediate plates are connected to the second output and grounded. The two remaining intermediate plates are connected to the first output. In yet another of these electrolysis devices (hereinafter: prior art 5), in addition to the two end plates, a total of two intermediate plates are present. One end plate and one intermediate plate are connected to the first output. The other end plate and the other intermediate plate are connected to the second output and grounded.The wiring is such that the intermediate plate connected to the first output is located between the two plates connected to the second output and, conversely, the intermediate plate connected to the second output is located between the two plates connected to the first output.

[0005] Furthermore, an electrolysis device (hereinafter: prior art 6) is also known which comprises a first and a second electrolysis unit, wherein the first and the second electrolysis units each comprise a first and a second end plate. In this electrolysis device, the electrolysis units have no intermediate plates, so that the stacks of electrolysis cells extend from the first to the second end plate of the respective electrolysis unit. In this electrolysis device, the first end plate of the first electrolysis unit and the first end plate of the second electrolysis unit are electrically connected to one another and grounded. The first output of the rectifier unit is connected to the second end plate of the first electrolysis unit, and the second output of the rectifier unit is connected to the second end plate of the second electrolysis unit.Connections for supplying and discharging electrolysis liquid (when supplying without electrolysis gas, when discharging with one of the electrolysis gases) are arranged in the area of ​​the first end plates of the two electrolysis units.

[0006] From CN 113 445 070 A it is known to electrically connect the intermediate plate of a stack of electrolysis cells, which is provided with connections, to a direct current unit. Summary of the invention

[0007] As part of the energy transition, so-called renewable energies are required on a considerable scale. One option for storing renewable energy is the electrolysis of water from electrical energy generated by photovoltaics, wind power or other environmentally friendly methods. During electrolysis, water is split into oxygen and hydrogen. The hydrogen is separated and stored and can then be transported to another location or used, for example, to power a motor vehicle. The associated electrolysis liquid is often an aqueous solution of potassium hydroxide (KOH), with the concentration usually ranging between 20% and 30%. In some cases, other liquids are used, and in rare cases, gases other than hydrogen and oxygen are produced.

[0008] During electrolysis, the aim is, of course, to operate as energy-efficiently as possible. One of the factors that influence energy efficiency is the operating voltage provided by the rectifier unit (= the difference between the two potentials provided via the first and second outputs). Typically, the losses within the rectifier unit are essentially proportional to the switched current, but relatively independent of the switched operating voltage. Increasing the operating voltage while maintaining the switched current therefore contributes to an improved energy balance.

[0009] The voltage required for a single electrolysis cell (cell voltage) is determined by the materials used for the electrodes and the electrochemical processes occurring during electrolysis. The cell voltage is typically in the range of a few volts. To utilize higher operating voltages (several hundred volts), a corresponding number of electrolysis cells must be connected in series.

[0010] However, losses also occur during the operation of an electrolysis unit. The associated heat must be dissipated from the electrolysis unit. These losses are primarily dissipated by the electrolysis fluid. As the number of electrolysis cells in a stack increases, the transport distances for the electrolysis fluid become longer. This makes heat dissipation more difficult. Therefore, it is not possible to increase the number of electrolysis cells in a stack indefinitely.

[0011] Furthermore, the end plates should be connected to earth potential whenever possible. This automatically ensures contact safety. Furthermore, it avoids various problems that arise when connecting the lines carrying the electrolysis fluid (with or without electrolysis gas) to the media connections, provided these have a potential different from earth potential.

[0012] The state-of-the-art solutions only address parts of the above-mentioned problems: In state-of-the-art 1, both end plates are not grounded. Furthermore, the entire voltage drop occurs in a single electrolysis unit, so only a relatively low operating voltage can be used, as otherwise the thermal losses cannot be dissipated.

[0013] In state-of-the-art technology 2, both end plates are grounded. However, only a relatively low operating voltage can be used, as otherwise the thermal losses cannot be dissipated.

[0014] In State of the Art 3, as in State of the Art 1, both end plates are not grounded. Furthermore, the entire voltage drop in a single electrolysis unit occurs, so only a relatively low operating voltage can be used.

[0015] In state-of-the-art 4, both end plates are grounded. However, only a single electrolysis unit is used, so only a relatively low operating voltage can be used.

[0016] In state-of-the-art technology 5, only one of the two end plates is grounded, so that only this end plate allows for trouble-free supply and discharge of the electrolysis liquid. Furthermore, the entire voltage drop in a single electrolysis unit is distributed, so only a relatively low operating voltage can be used.

[0017] In prior art 6, two electrolysis units are present, electrically connected in series. Therefore, a relatively high operating voltage can be used, since the operating voltage drop is distributed across both electrolysis units. However, only one end plate is grounded in each of the two electrolysis units. The connections for supplying and discharging the electrolysis fluid are located only in the area of ​​these end plates. Therefore, even in prior art 6, the operating voltage can only be increased relatively slightly, since otherwise the associated thermal losses can no longer be dissipated.

[0018] The object of the present invention is to provide possibilities by means of which the problems of the prior art are completely avoided.

[0019] The object is achieved by an electrolysis device having the features of claim 1. Advantageous embodiments of the electrolysis device are the subject of dependent claims 2 to 11.

[0020] According to the invention, an electrolysis device is provided in which the electrolysis device comprises a first and a second electrolysis unit, the first and the second electrolysis units each comprise a first and a second end plate, the first and the second electrolysis units each have a respective intermediate plate arranged approximately or exactly in the middle between the respective first and the respective second end plate, the first and the second electrolysis units each have a stack of electrolysis cells between the respective intermediate plate and each of the two respective end plates, the electrolysis cells of the respective stack are each electrically connected in series, the electrolysis cells each have a first electrode and a second electrode at which an electrolysis liquid is partially electrolytically split,so that the remaining electrolysis liquid after the electrolytic splitting is mixed with a first electrolysis gas in the region of the respective first electrode and with a second electrolysis gas in the region of the respective second electrode, the first end plate of the first electrolysis unit and the first end plate of the second electrolysis unit are electrically connected to one another, the second end plate of the first electrolysis unit and the second end plate of the second electrolysis unit are electrically connected to one another, the electrolysis device has a rectifier unit which provides a first potential via a first output and a second potential via a second output,and the first output of the rectifier unit is electrically connected to a terminal of the intermediate plate of the first electrolysis unit and the second output of the rectifier unit is electrically connected to a terminal of the intermediate plate of the second electrolysis unit. ,

[0021] From an electrical perspective, such an electrolysis device allows for high operating voltages. This is because the operating voltage can be distributed across the stacks of electrolysis cells of two electrolysis units. Furthermore, neither of the two potentials provided by the rectifier unit is present at any of the end plates. Therefore, the lines for the electrolysis fluid can be easily connected to all end plates. This also allows the losses generated during operation of each electrolysis unit to be dissipated via both end plates, maximizing the number of electrolysis cells per stack and thus per electrolysis unit.

[0022] Preferably, the first and second end plates of the first and second electrolysis units are electrically connected to one another. This further simplifies the operation of the electrolysis device. Regardless of the specific potential of the end plates, the potential of the end plates is consistently the same for all four end plates. In this case, it is particularly preferred if the first and second end plates of the first and second electrolysis units are electrically grounded—either directly for each end plate or indirectly for at least one of the end plates via one of the other end plates.

[0023] Preferably, the rectifier unit is configured such that it provides the first and second potentials without a fixed reference to ground. This configuration simplifies the design of the rectifier unit and also simplifies the operation of the electrolysis device as a whole. Decoupling the rectifier unit from ground potential can be achieved particularly easily by placing a transformer unit upstream of the rectifier unit, via which the electrical energy required for its operation is supplied to the rectifier unit.

[0024] Preferably, the first and second end plates of the first and second electrolysis units have media connections for supplying the electrolysis liquid, for discharging the electrolysis liquid mixed with the first electrolysis gas, and for discharging the electrolysis liquid mixed with the second electrolysis gas. This allows the corresponding lines to be connected to both end plates of both electrolysis units, thus optimizing heat dissipation and the general operation of the electrolysis device.

[0025] In some embodiments, the intermediate plates have no passages for the electrolysis liquid, so that the flow direction of the electrolysis liquid is reversed at the respective intermediate plate. As a result, the two stacks of a respective electrolysis unit operate separately from one another in terms of fluid technology. Alternatively, it is possible for the intermediate plates to have only passages for the electrolysis liquid (i.e., without electrolysis gases), but no passages for the electrolysis liquid mixed with the first electrolysis gas and the electrolysis liquid mixed with the second electrolysis gas. In this case, even with different pressure drops from the two end plates of a respective electrolysis unit to the intermediate plate of the respective electrolysis unit, the best possible flow through the electrolysis cells and thus good heat dissipation is achieved.Alternatively, it is possible for the intermediate plates to have passages for both the electrolysis liquid and the electrolysis liquid mixed with the first electrolysis gas, and the electrolysis liquid mixed with the second electrolysis gas. However, at least the passages for the electrolysis liquid mixed with the first electrolysis gas and the electrolysis liquid mixed with the second electrolysis gas are separate from each other and separate from the passages for the electrolysis liquid as such (i.e., without electrolysis gases).

[0026] Preferably, the first and second electrolysis units are arranged next to one another such that the directions from the respective first end plate to the respective second end plate run parallel and, viewed in the directions mentioned, the first end plates are arranged at the same height and / or the second end plates are arranged at the same height. This not only minimizes the required footprint as such, but also results in short paths for the cable routing from the rectifier unit to the connections of the intermediate plates. This applies in particular if the rectifier unit is located in front of the first end plates in the direction from the respective first end plate to the respective second end plate of a respective electrolysis unit and, viewed orthogonally to the directions mentioned, is located in the region between the two sides of the two electrolysis units facing away from the other electrolysis unit.The optimization is particularly great if the connection of the intermediate plate of the first electrolysis unit is arranged on the side of the first electrolysis unit facing the second electrolysis unit and, conversely, the connection of the intermediate plate of the second electrolysis unit is arranged on the side of the second electrolysis unit facing the first electrolysis unit.

[0027] The rectifier unit preferably comprises transistors, in particular FETs or IGBTs, for switching the first and second potentials to the first and second outputs. This results in optimized operation of the rectifier unit. Short description of the drawings

[0028] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of the embodiments, which are explained in more detail in conjunction with the drawings. Herein, in schematic representation: FIG 1 shows an electrolysis device from above, FIG 2 shows an electrical connection of a stack of electrolysis cells, FIG 3 shows the structure of a single electrolysis cell and FIG 4 shows a functional connection of the electrolysis device from FIG 1 . Description of the embodiments

[0029] According to FIG 1 an electrolysis device comprises a first electrolysis unit 1 and a second electrolysis unit 2. The first electrolysis unit 1 comprises a first end plate 3 and a second end plate 4 as well as - approximately or exactly - in the middle between the two end plates 3, 4 an intermediate plate 5. In an analogous manner, the second electrolysis unit 2 comprises a first end plate 6 and a second end plate 7 as well as - approximately or exactly - in the middle between the two end plates 6, 7 an intermediate plate 8.

[0030] The electrolysis device further comprises four stacks of electrolysis cells 9. Each of the stacks extends from the intermediate plate 5 of the first electrolysis unit 1 to the first end plate 3 of the first electrolysis unit 1, from the intermediate plate 5 of the first electrolysis unit 1 to the second end plate 4 of the first electrolysis unit 1, from the intermediate plate 8 of the second electrolysis unit 2 to the first end plate 6 of the second electrolysis unit 2 and from the intermediate plate 8 of the second electrolysis unit 2 to the second end plate 7 of the second electrolysis unit 2.

[0031] The electrolysis cells 9 of the stacks are electrically connected in series within each stack. This is shown in FIG 2 for the stack extending from the intermediate plate 5 of the first electrolysis unit 1 to the first end plate 3 of the first electrolysis unit 1. Analogous facts apply to the other stacks.

[0032] The electrolysis cells 9 themselves have FIG 3 each have a first electrode 10 and a second electrode 11. An electrolysis liquid 12 is pumped through the electrolysis cells 9. The electrolysis liquid 12 is electrolytically split at the electrodes 10, 11. The splitting produces a first electrolysis gas 13 and a second electrolysis gas 14. Membranes 15 are usually arranged in the electrolysis cells 9, which are permeable to ions contained in the electrolysis liquid 12, but not to the electrolysis gases 13, 14. The structure and mode of operation of the electrolysis cells 9 are generally known to those skilled in the art. Typically, the electrolysis liquid 12 is an aqueous solution of potassium hydroxide, and the electrolysis gases 13, 14 are hydrogen and oxygen. In principle, however, the present invention is not limited to this specific embodiment.

[0033] The electrolysis liquid 12 is only partially split. Due to the splitting at the electrodes 10, 11, the remaining electrolysis liquid 12 is mixed with the first electrolysis gas 13 in the region of the first electrode 10 and with the second electrolysis gas 14 in the region of the second electrode 11.

[0034] As explained so far, the structure of the electrolysis device is conventional in nature and therefore does not need to be explained in more detail.

[0035] According to FIG 4 This represents a minimal configuration: firstly, the first end plates 3, 6 of the two electrolysis units 1, 2 are electrically connected to one another, and secondly, the second end plates 4, 7 of the two electrolysis units 1, 2 are electrically connected to one another. Preferably, all four end plates 3, 4, 6, 7 are electrically connected to one another. In particular, the four end plates 3, 4, 6, 7 can be electrically grounded.

[0036] The electrolysis device further comprises a rectifier unit 16. The rectifier unit 16 provides a first potential P1 via a first output 17 and a second potential P2 via a second output 18. Preferably, the rectifier unit 16 is designed such that it provides the potentials P1, P2 without a fixed reference to ground. This is shown in FIG 4 indicated by a grounding symbol being crossed out at the rectifier unit 16. Furthermore, the rectifier unit 16 has, as shown in FIG 4 For switching the first and second potentials P1, P2 to the first and second outputs 17, 18, transistors are preferably used. The transistors can be, for example, FETs or IGBTs.

[0037] The potentials P1, P2 have different values. Their difference thus defines an output voltage U of the rectifier unit 16, which simultaneously represents the operating voltage of the electrolysis device. The first output 17 of the rectifier unit 16 is electrically connected to a terminal 19 of the intermediate plate 5 of the first electrolysis unit 1. Similarly, the second output 18 of the rectifier unit 16 is electrically connected to a terminal 20 of the intermediate plate 8 of the second electrolysis unit 2.

[0038] The electrolysis liquid 12 must be supplied to the electrolysis units 1, 2. Furthermore, the electrolysis liquid 12 mixed with the two electrolysis gases 13, 14 must be discharged from the electrolysis units 1, 2 again - separately for both electrolysis gases 13, 14. For this purpose, at least one of the end plates 3, 4, 6, 7 of each electrolysis unit 1, 2 has media connections 21. Preferably, as shown in FIG 4 even both end plates 3, 4, 6, 7 of both electrolysis units 1, 2 have the corresponding media connections 21.

[0039] For each end plate 3, 4, 6, 7 with media connections 21, at least three media connections 21 are provided, namely one each for supplying the electrolysis liquid 12, for discharging the electrolysis liquid 12 mixed with the first electrolysis gas 13, and for discharging the electrolysis liquid 12 mixed with the second electrolysis gas 14. Optionally, four media connections 21 may also be provided. In this case, the electrolysis liquid 12 is supplied separately to the area of ​​the first electrodes 10 and the area of ​​the second electrodes 11.

[0040] The intermediate plates 5, 8 can have passages for the passage of the electrolysis liquid 12 (with and without electrolysis gases 13, 14). However, at least the passages for the electrolysis liquid 12 mixed with the first electrolysis gas 13 and the electrolysis liquid 12 mixed with the second electrolysis gas 14 are separate from one another and separate from the passages for the electrolysis liquid 12 as such (i.e., without electrolysis gases 13, 14). Alternatively, the intermediate plates 5, 8 do not have such passages. The flow direction of the electrolysis liquid 12 is thus reversed at the respective intermediate plate 5, 8, so that it first flows from one of the end plates 3, 4, 6, 7 to the respective intermediate plate 5, 8 and then flows back to the same end plate 3, 4, 6, 7.Alternatively, the intermediate plates 5, 8 may only have passages for the electrolysis liquid 12 (i.e. without electrolysis gases 13, 14), but no passages for the electrolysis liquid 12 mixed with the first electrolysis gas 13 and the electrolysis liquid 12 mixed with the second electrolysis gas 14.

[0041] The rectifier unit 16 must be supplied with the electrical energy required for its operation. This is preferably provided from a supply network 22. Regardless of the type of supply, however, a transformer unit 23 is preferably arranged upstream of the rectifier unit 16. The supply network 22, the transformer unit 23, and the rectifier unit 16 (the latter only on the input side) are preferably three-phase. However, this is not mandatory.

[0042] According to the presentation in FIG 1The first and second electrolysis units 1, 2 are arranged side by side. The directions from the respective first end plate 3, 6 to the respective second end plate 4, 7 thus run parallel. Viewed in these directions, the first end plates 3, 6 are preferably arranged at the same height. Alternatively or additionally (the latter is preferred), the second end plates 4, 7 can also be arranged at the same height.

[0043] The rectifier unit 16 is preferably arranged in front of the electrolysis units 1, 2. This means specifically that the rectifier unit 16 is located in front of the first end plates 3, 6, as seen in the direction from the respective first end plate 3, 6 to the respective second end plate 4, 7 of a respective electrolysis unit 1, 2, and, as seen orthogonally to the aforementioned directions, is located in the region between the two sides of the two electrolysis units 1, 2 facing away from the respective other electrolysis unit 2, 1.

[0044] Furthermore, the connection 19 of the intermediate plate 5 of the first electrolysis unit 1 is preferably arranged on the side of the first electrolysis unit 1 facing the second electrolysis unit 2. In an analogous manner, the connection 20 of the intermediate plate 8 of the second electrolysis unit 2 is preferably arranged on the side of the second electrolysis unit 2 facing the first electrolysis unit 1.

[0045] The present invention offers many advantages. In particular, it provides simple and superior operation of the electrolysis device, both in terms of fluid technology and electrical engineering, and is also energy-efficient.

[0046] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variants can be derived therefrom by those skilled in the art without departing from the scope of the invention. List of reference symbols

[0047] 1, 2 Electrolysis units 3, 4, 6, 7 End plates 5, 8 Intermediate plates 9 Electrolysis cells 10, 11 Electrodes 12 Electrolysis liquid 13, 14 Electrolysis gases 15 Membrane 16 Rectifier unit 17, 18 Outputs 19, 20 Connections 21 Media connections 22 Supply network 23 Transformer unit P1, P2 Potentials U Output voltage

Claims

1. An electrolysis device, - wherein the electrolysis device comprises a first and a second electrolysis unit (1, 2), - wherein the first and the second electrolysis unit (1, 2) each comprise a first and a second end plate (3, 4, 6, 7), - wherein the first and the second electrolysis unit (1, 2) each include a respective intermediate plate (5, 8) arranged approximately or exactly in the middle between the respective first and the respective second end plate (3, 4, 6, 7), - wherein the first and the second electrolysis unit (1, 2) each include a stack of electrolysis cells (9) between the respective intermediate plate (5, 8) and each of the two respective end plates (3, 4, 6, 7), - wherein the electrolysis cells (9) of the respective stack are each electrically connected in series, - wherein the electrolysis cells (9) each include a first electrode (10) and a second electrode (11) at which an electrolysis liquid (12) is partially electrolytically split, so that the remaining electrolysis liquid (12) is admixed after the electrolytic splitting with a first electrolysis gas (13) in the area of the respective first electrode (10) and with a second electrolysis gas (14) in the area of the respective second electrode (11), - wherein the first end plate (3) of the first electrolysis unit (1) and the first end plate (6) of the second electrolysis unit (2) are electrically connected to one another, - wherein the second end plate (4) of the first electrolysis unit (1) and the second end plate (7) of the second electrolysis unit (2) are electrically connected to one another, - wherein the electrolysis device includes a rectifier unit (16), which provides a first potential (P1) via a first output (17) and provides a second potential (P2) via a second output (18), and - wherein the first output (17) of the rectifier unit (16) is electrically connected to a terminal (19) of the intermediate plate (5) of the first electrolysis unit (1) and the second output (18) of the rectifier unit (16) is electrically connected to a terminal (20) of the intermediate plate (8) of the second electrolysis unit (2).

2. The electrolysis device as claimed in claim 1, characterized in that the first and the second end plate (3, 4, 6, 7) of the first and the second electrolysis unit (1, 2) are electrically connected to one another.

3. The electrolysis device as claimed in claim 2, characterized in that the first and the second end plate (3, 4, 6, 7) of the first and the second electrolysis unit (1, 2) are electrically grounded.

4. The electrolysis device as claimed in claim 3, characterized in that the rectifier unit (16) is designed in such a way that it provides the first and the second potential (P1, P2) without fixed reference to ground.

5. The electrolysis device as claimed in claim 4, characterized in that a transformer unit (23) is arranged upstream of the rectifier unit (16), via which the rectifier unit (16) is supplied with the electrical energy required for its operation.

6. The electrolysis device as claimed in any one of the preceding claims, characterized in that the first and the second end plate (3, 4, 6, 7) of the first and the second electrolysis unit (1, 2) include media fittings (21) for supplying the electrolysis liquid (12), for discharging the electrolysis liquid (12) admixed with the first electrolysis gas (13), and for discharging the electrolysis liquid (12) admixed with the second electrolysis gas (14).

7. The electrolysis device as claimed in claim 6, characterized in that the intermediate plates (5, 8) - do not include passages for the electrolysis liquid (12), so that the flow direction of the electrolysis liquid (12) is reversed at the respective intermediate plate (5, 8), or - only include passages for the electrolysis liquid (12), but do not include passages for the electrolysis liquid (12) admixed with the first electrolysis gas (13) and the electrolysis liquid (12) admixed with the second electrolysis gas (14), or - include passages for both the electrolysis liquid (12) and the electrolysis liquid (12) admixed with the first electrolysis gas (13) and the electrolysis liquid (12) admixed with the second electrolysis gas (14).

8. The electrolysis device as claimed in any one of the preceding claims, characterized in that the first and the second electrolysis unit (1, 2) are arranged adjacent to one another, so that the directions from the respective first end plate (3, 6) to the respective second end plate (4, 7) extend in parallel and, viewed in the mentioned directions, the first end plates (3, 6) are arranged at the same height and / or the second end plates (4, 7) are arranged at the same height.

9. The electrolysis device as claimed in claim 8, characterized in that the rectifier unit (16), viewed in the direction from the respective first end plate (3, 6) to the respective second end plate (4, 7) of a respective electrolysis unit (1, 2) is located in front of the first end plates (3, 6) and, viewed orthogonally to the mentioned directions, is located in the area between the two sides of the two electrolysis units (1, 2) facing away from the respective other electrolysis unit (2, 1).

10. The electrolysis device as claimed in claim 8 or 9, characterized in that the terminal (19) of the intermediate plate (5) of the first electrolysis unit (1) is arranged on the side of the first electrolysis unit (1) facing toward the second electrolysis unit (2), and the terminal (20) of the intermediate plate (8) of the second electrolysis unit (2) is arranged on the side of the second electrolysis unit (2) facing toward the first electrolysis unit (1).

11. The electrolysis device as claimed in any one of the preceding claims, characterized in that the rectifier unit (16) includes transistors, in particular FETs or IGBTs, for switching the first and the second potential (P1, P2) at the first and the second output (17, 18).