DE10306342B4 - electrolyzer - Google Patents

Abstract

Electrolysis apparatus (1), comprising at least one electrolysis cell (3) with a power connection, with two electrolyte feeds (6a, b, 35), one serving as catholyte supply (6a) and the other as anolyte supply (6b), and two gas discharges (7a, b) and a high pressure suitable housing (2) with a current feedthrough and two gas outlets (8a, b), wherein the at least one electrolysis cell (3) in the housing (2) is arranged and at least one electrolyte supply (6a, b, 35) in the housing interior begins, so that the housing (2) serves as an electrolyte reservoir, characterized
that one of the gas discharges (7b) is connected to one of the gas outlets (8b) for discharging oxygen and the other gas discharge (7a) inside the housing ends for introducing hydrogen, so that the housing (2) serves as a hydrogen storage, and
a differential pressure regulator (24) is provided at the gas outlets (8a, b) in order to minimize the pressure difference within the at least one electrolysis cell (3).

Description

The The invention relates to an electrolysis apparatus comprising an electrolytic cell having a power connection, having two electrolyte feeds, wherein one serves as Katholytzufuhr and the other as anolyte supply, and two gas outlets as well as a high pressure suitable housing with a current feedthrough and two gas outlets wherein the at least one electrolytic cell is arranged in the housing is and at least one electrolyte feed begins inside the housing, so that the housing serves as an electrolyte store.

Such an electrolysis device is known from DE 101 50 557 C1 known. The electrolytic cell is connected to both a catholyte and an anolyte circuit and therefore also has two electrolyte feeders and two gas outlets, wherein at least one electrolyte feed begins inside the housing, so that the housing also serves as an electrolyte reservoir.

The interior of the housing is divided by a diaphragm into two spaces, wherein in the separate room oxygen and in the other room hydrogen is collected and withdrawn. To what extent a collection of hydrogen takes place without deducting it at the same time, ie a storage of hydrogen is provided, goes out of the DE 101 50 557 C1 not apparent.

With Help the electrolysis can from water or aqueous solutions high-purity gases are obtained. In the electrolysis of water can oxygen and hydrogen can be recovered from aqueous fluoride solution Fluorine can be obtained from aqueous chloride solution Chlorine can be recovered. The high purity gases thus obtained can be e.g. used in gas chromatography and spectroscopy. There is also a great deal of interest in hydrogen as energy storage, can be fed with the fuel cell.

Especially in the field of hydrogen generators has been researched for some time. For example, from the EP 0 055 134 A1 a hydrogen generator is known in which hydrogen is obtained on the basis of chemical conversion of base metals. However, this is very uneconomical.

From the JP 8 176 873 A and JP 8 193 286 A High-pressure hydrogen generators are known in which a hollow cathode is used for the hydrogen production. In the hollow cathode, the hydrogen is compressed and the pressure thus built up is used for energy or heat.

According to the JP 9 291 386 A For example, a reaction tank in which electrolysis takes place and a phase separator tank are stacked. From the reaction tank, the oxygen is removed immediately. The hydrogen is supplied via a gas line to the phase separator tank and derived from there.

From the US 3,933,614 is a high-pressure housing for hydrogen generators known. The metal housing consists of an upwardly open container and a tightly connected lid. In the lid are provided for the supply of water, and the oxygen and hydrogen removal. The interior of the housing is dimensioned such that an electrolytic cell with an asbestos membrane for separating the half-cells fits into the housing and is surrounded by electrolytes. The two half-cells are gas-tight separated from each other. Both the hydrogen and the oxygen are discharged directly from the housing.

The US 3,374,158 describes an electrolysis system of a plurality of electrolytic cells in which a portion of the recovered gases for cooling and refilling the electrolyte solution is returned to the system. In addition, the pressure conditions are controlled so that the pressure difference between the two half-cells is as small as possible on the membrane.

In the water electrolysis system of US 6,375,812 is provided for the electrolyte, a closed water cycle. The non-electrolyzed water is separated in a phase separator from the recovered gases. The water circulates on the one hand with the help of gravity and on the other hand with the help of the pressure differences, which result from the fact that the product gas is led away.

From the US Pat. No. 6,303,009 B1 a hydrogen generator is known in which water is electrolyzed by means of a proton exchange membrane. The power supply for the electrolysis reaction is controlled by a computer such that the hydrogen partial pressure remains substantially constant, although hydrogen is removed. In addition, the lifetime of the generator is extended by the fact that pressure difference is kept as low as possible on the membrane.

In the US 5,494,559 is described an electrolysis system in which the electrolysis takes place via a plurality of polymer beads, which are coated conductive. The electrolysis cell is supplied with a pump with electrolyte. The product gases hydrogen and oxygen are removed via a phase separator.

In the case of the hydrogen and oxygen genera gate according to US 5,690,797 an electrolysis cell is immersed in ionized water. Both the oxygen and the hydrogen are removed via separators. A differential pressure regulator ensures that the differential pressure remains essentially constant. In addition, the level of ionized water is controlled and this information is used to control the pressures and replenish ionized water.

apart the provision of high purity gases for analysis is always available more the extraction of hydrogen and its use as energy storage in the foreground. Especially in the course of intensified use regenerative energies such as wind and solar energy is it necessary, To provide compact electrolysis devices, with their Help transform the regenerative energies into storable energies be and can be stored the devices simultaneously serve to store the stored energy transport or decentralized.

These Task is solved by an electrolytic apparatus according to claim 1.

The inventive device is characterized by an extremely compact design. All important Components such as electrolysis cell, electrolyte storage and product gas storage as well as the necessary connections are in a single housing integrated. On the one hand, this makes the device according to the invention easily transportable. By offering the opportunity, both one It can be used to store electrolyte as well as a gas storage be used in environments where maintenance is rarely possible or economical are meaningful. Furthermore the device is self-sufficient, as they only a power source needed. The device according to the invention can be everywhere be connected where, e.g. about renewable energy electricity is won. With the help of the device according to the invention this is Electricity converted by the electrolysis of water into energies of chemical form and saved that energy.

Thereby, that the case high pressure is ensured, that big Amounts of product gas can be stored. Preferably it is the case around a printing cylinder. And it can be e.g. a conventional one Steel impression cylinders act or around an aluminum cylinder with kevlar cladding. Although they are similar To press like steel cylinders, they are comparatively light. Therefore, such pressure cylinders are particularly suitable for applications the device according to the invention, where it depends on easy transportability. Under high pressure is understood here a pressure of 10 bar to over 200 bar.

By doing Although the half-cells of at least one electrolysis cells by means are flooded at least one electrolyte supply, although ensures a gas-tight separation of the half-cells. Because of the extreme high explosiveness however, oxyhydrogen gas is preferred, two separate electrolyte feeds for the Provide catholyte and the anolyte. Especially with electrolysis cell stacks from a variety of electrolysis cells, it has also from Advantage proven when the two electrolyte feeds switched so are that the electrolytic cell stack in countercurrent principle with Electrolyte is applied. Among other things, this is a more homogeneous Pressure distribution and heat distribution over the Ensured electrolytic cell stack.

In the at least one electrolytic cell is affected by the cell resistance Ohmic heat produced. It has proved to be advantageous, this heat by means of passive cooling elements dissipate. Particularly preferred are attached to the outer wall of the housing Cooling fins. In extreme temperature conditions it may be necessary, in addition active cooling measures to provide for example in the form of convection.

In a preferred embodiment In each electrolyte supply, a pump is arranged around the electrolyte to pump into the at least one electrolysis cell. Preferably it is a circulating pump, the no cavities has, so that within the pump, a complete pressure equalization guaranteed is. In this case, the circulation pump only the inside of the housing overcome the prevailing pressure difference, to pump electrolyte into the at least one electrolysis cell.

Of the Electrolyte is refilled in certain operating cycles. Possibly An electrolyte level control may be provided. It's closed consider, that the at least one electrolysis cell stops its operation, and no electrolyte is there anymore, but is used up. Because then flows in the electrolysis cycle no more power.

ever according to the location of the device according to the invention can also be be provided continuous electrolyte inflow. For that would have to the electrolyte inlet of the housing a high-pressure pump may be provided which contains the electrolyte in the high pressure housings transported.

When filling with electrolyte, it must be taken into consideration that not too much electrolyte is filled into the housing, because then only a limited volume would be available as product gas storage. But it must not be filled too little electrolyte, otherwise the electrolysis stop prematurely would pen.

In a particularly preferred embodiment, the at least one electrolysis cell is a thin-layer cell. Thin-film cells are used eg in the DE 198 41 302 C2 described. Thin-film cells are characterized in that the two electrodes of a cell are separated only by a capillary gap. Therefore, they have a very low ohmic resistance. In addition, no electrolyte salt is needed in the electrolysis of water. Thin-film cells can be made very small and compact. In addition, they have a very high efficiency due to their high area-volume ratio.

When another possibility for electrolysis cells offer membrane electrode assemblies (MEA membrane electrode assembly). These are e.g. from the fuel cell technology known. They point a membrane that with porous Material is coated as an electrode.

When In this case, the use of electrical has particularly advantageous conductive Membranes exposed in the electrolysis cells. Especially preferred become polymer electrolyte membranes. Very particularly preferred the combination of thin-film cells with electrically conductive Membrane.

The thin-film cells must be compared to those in the DE 198 41 302 C2 shown thin-film cells with a liquid channel have a slightly different geometry, since in the half-cells, a gas liquid mixture is located, which must be able to flow freely. Preferably, therefore, plate-shaped electrodes or membranes should be provided, which are spaced apart, for example, by means of support points or nets. In addition, it is advantageous to form the electrolytic cells not rectangular but circular so that they give a cylindrical shape when stacked. Cylinders have the advantage that there is less sealing surface and therefore this form is suitable for high pressure applications and a cylinder requires less space in the pressure housing.

One Phase separator consists essentially of a container, in the electrolyte settles down and outgas the gas. To the electrolyte preferably to be able to use intensively and one as possible To obtain pure gas, it has been found to be advantageous a phase separator for to provide the gas to be stored. This phase separator is on the appropriate gas discharge before its mouth in the housing to install.

Around to increase the operating time with an electrolyte filling is preferably a further phase separator for the gas to be discharged in the corresponding Gas discharge provided. So that the gases are as aerosol-free as possible, can still frit provided at the output of the respective phase separator which lets through the gas, but not the electrolyte droplets. If it is the gas to be stored to hydrogen for use in fuel cells, the hydrogen can to some extent be water vapor. The recovered electrolyte in the separator is returned to the normal electrolyte volume, from where he possibly has a circulating pump is pumped back into the at least one electrolysis cell.

In a particularly preferred embodiment is at the gas outlets provided a differential pressure regulator, which serves to the pressure difference within the at least one electrolytic cell possible to keep low. In electrolysis e.g. arising from water for one volume of oxygen, two volumes of hydrogen. By acting for the Gas one as possible great Volume is held up and for the to be discharged Gas one as possible Small internal volume, ensures that a sufficient Counterpressure is built up. about the differential pressure regulator is drained only so much gas to be discharged that the differential pressure remains constant. Altogether thereby becomes in the at least one electrolysis cell at the intermediate membrane a pressure difference maintained at substantially zero. This increases significantly the life of the electrolytic cell.

Especially preferred because of its compact design is the embodiment, at the case having a lid in the current feedthrough, the electrolyte inlet and the two gas outlets are integrated and at which the at least one electrolysis cell is attached. This embodiment has the advantage that all essential components are easily accessible and easy to install and remove.

The inventive device can be designed as a disposable device with before use Electrolyte filled has been. This solid supply of electrolyte would not be refilled. After use or after emptying the recovered product gas, it could either be disposed of or refilled after opening the housing. In a preferred embodiment shows the case an electrolyte inlet to the device already during the Refill the operation with electrolyte to be able to or in a simple way, the device after use fill to be able to.

The Invention is based on the following figures for the example of water electrolysis be explained in more detail.

It demonstrate:

1 a schematic diagram of a first embodiment of the device according to the invention;

2 a schematic diagram of another embodiment of the device according to the invention;

3a a section through an electrolyzer;

3b a section through a electrolytic device with continuous electrolyte supply;

4a an exploded view of an electrolytic cell;

4b the elements of the electrolytic cell in plan view

5a a section through an electrolytic cell;

5b a section through another electrolysis cell;

6 the dependence of the hydrogen pressure and the decomposition voltage on the electrolysis time.

In 1 schematically a first embodiment of the device according to the invention is shown. The electrolysis device 1 consists essentially of a housing 2 in which an electrolysis cell 3 is arranged from two half-cells. They are also in the case 2 an electrolyte 4 ie water, and a gas to be stored 5 ie hydrogen. The electrolytic cell 3 has two separate electrolyte feeds 6a and 6b for each half cell. It also has two gas outlets 7a and 7b on, with the gas discharge 7a inside the case 2 ends and the gas discharge 7b with the gas outlet 8b connected is. About the gas discharge 7b and the gas outlet 8b the oxygen produced in one half-cell is directly removed. About the gas discharge 7a The hydrogen produced in the other half cell penetrates into the interior of the housing 2 , There it can be enriched or via the gas outlet 8a be dissipated.

The arrangement in 2 is essentially consistent with the one in 1 match. In addition, there are two pressure gauges 10a and 10b as well as a valve 9 , The pressure gauge is used to measure the hydrogen partial pressure; the pressure gauge 10b serves to measure the difference between the hydrogen partial pressure and the oxygen partial pressure. About the valve 9 the discharged oxygen flow can be regulated.

The volume of oxygen corresponds to the volumes of a half cell and the gas discharge 7b and the gas outlet 8b , The volume of hydrogen corresponds to the volume of a half cell plus the volume of the gas discharge 8a in addition to the internal volume of the housing minus the volumes of the electrolysis cell and the water 4 , Since in the electrolysis of water two parts of hydrogen to a part of oxygen and the oxygen is continuously removed while the hydrogen is stored, is ensured by this certain volume ratio, that nevertheless a sufficient oxygen back pressure can build up to the hydrogen pressure. Deviations are via the valve 9 and the meter 10b regulated. This regulated pressure conditions ensures that within the electrolytic cell 3 , namely on both sides of the membrane, the same pressure prevails, so the pressure difference is minimal. As a result, it is also possible to use electrolysis cells with mechanically less stable membranes.

3a shows an electrolyzer 1 on average. In a high pressure cylinder 26 is an electrolysis cell stack 20 arranged via power connectors with an external power supply 31 connected is. In addition, the electrolysis cell stack points 20 an electrolyte feed 35 on that in the water 4 protrudes and a circulation pump 25 having. The circulating pump is a low pressure pump for pressures <10 × 10 ⁵ Pascals. At the electrolysis cell stack 20 it is a bipolar arrangement. The individual intermediate cells are in the electric field between the anode 21 and cathode 22 polarized. It therefore requires no extra contact for each cell, but only one contact for the anode 21 and a contact for the cathode 22 , At the gas outlets 36 and 37 is a phase separator 23 arranged for the separation of gaseous electrolysis products from the electrolyte, ie hydrogen or oxygen and water. In this case, two separation units are provided for each one and the other electrolysis product. About the derivation 41 the recovered electrolyte becomes the electrolyte reservoir 4 fed. The electrolysis product to be stored, eg hydrogen, is via the gas discharge 36 the inner housing 2 supplied, the other electrolysis product, for example oxygen, is via the gas outlet 37 dissipated. The gas outlets are followed by a differential pressure gauge and regulator 24 at. He has an outlet 32 for the stored electrolysis product and an outlet 33 for the unsaved electrolysis product. The connections for both the electricity and the gases are in the lid 27 integrated. This contributes to a compact design of the entire device. To cool the entire device, it has outside of the housing cooling fins 28 on.

In the 3b shown device is compared with the in 3a illustrated modified in that an external electrolyte reservoir tank 40 is provided, from the means of an external Hochdruckelektrolytspeisepumpe 39 and an external high pressure electrolyte supply 38 continuous electrolyte 4 is refilled.

Do you operate the device 1 as a storage for the hydrogen, it must be permanently a circulating pump 25 be used for the water cycle. Because the extracted oxygen does not build up a sufficient pressure gradient to the water by itself in the electrolysis cells 20 pull up. If you do not store the hydrogen, but also remove it continuously, you only need a circulating pump for so long 25 until the electrolysis cell stack 20 sufficiently wetted and enough hydrogen is produced that builds up a sufficient pressure difference when releasing the hydrogen. Then you would the electrolyte supply 35 lead via a bypass to the circulation pump 25 to get around.

At higher delivery pressure you can use the circulation pump 25 also replace with a piston assembly. The piston would then move over the building up hydrogen pressure and would press the water into the electrolysis cells.

For electrolytic cell stacks 20 From a very large number of electrolysis cells should the electrolysis cell stack 20 be supplied with electrolyte according to the countercurrent principle, to prevent over the stack of the electrolyte pressure drops too much.

The in the 3a and 3b The device shown is designed to be operated at up to 200 bar.

In 4a shows the construction of a thin-layer electrolysis cell, which has been specially adapted for use in the electrolysis device according to the invention. It is composed of two bipolar plates 11 , a channel plate 13 for the cathode 22 and a channel plate 14 for the anode 21 , Between the individual plates 11 . 13 . 14 are seals 12 arranged. Between the channel plates 13 . 14 is an ion-conductive polymer membrane 17 gas-tight with a seal 12 arranged. On it is a porous electrode 16 , which in the present case consists of porous nickel on nickel fabric. As a spacer between electrode 10 or conductive membrane 17 and the bipolar plates 11 is also a spacer 15 made of a fabric. This tissue may be electrically insulating or conductive. If it is electrically insulating, then the electrode must be 16 via a separate contact with the corresponding plate 11 get connected.

In 4b these just explained elements are to be seen in the plan view. The membrane 17 should be electrically conductive and mechanically stable. Therefore one likes to use composite membranes, eg made of Kevlar. The membranes can be reinforced with an insulated reinforcement fabric. Maybe this reinforcing fabric is made of kevlar. If it is a polymer electrolyte membrane, it can also consist of a polytetrafluoroethylene with sulfone groups, for example of Nafion. If, as in the present example, a membrane electrode assembly is used, the porous electrode can be used 16 also consist of soot, which is glued with polytetrafluoroethylene. Another than 16a shown electrode consists of fiber material, such as graphite felt. The spacer 15 does not have to be just fabric. It may also, like as 15a shown to act a spacer with fluid guide.

at The electrolysis of fluorine or chlorine can be the same membranes be used as for the hydrogen electrolysis. However, one should for the electrodes Use titanium. Otherwise chlorine should be dimensionally stable Use anodes as known from chloralkali electrolysis. With the help of the illustrated device can by the electrolysis heavy water can also be used to produce deuterium. Indeed must be considered in the power supply of the electrolysis cells be that heavy water has a higher decomposition stress than has normal water.

Except for titanium, that will etch well leaves, so that's a rough and very big one surface Stainless steel is also preferably used as the electrode material used. Because stainless steel is relatively cheap and easy on conventional Kind of edit. Furthermore it is mechanically and chemically resilient. Furthermore, stainless steel usually nickel content which has a positive effect on the electrode properties impact.

For better understanding is in the 5a and Figure b shows a section through two electrolysis cells. In the electrolytic cell according to 5a be through an electrically conductive membrane 17 between two bipolar plates 11 is arranged, two half-cells formed. The conductive membrane 17 is provided on both sides with a porous electrode. The cathodic half-cell is a porous electrode 16a made of graphite felt with catalyst coating, eg platinum. Alternatively, a porous electrode could be used 16 be provided from porous nickel on nickel fabric. The anodic half-cell is a porous electrode 16 made of porous nickel on nickel fabric. As a spacer between the membrane 17 with the electrodes 16 and 16a as well as the plates 11 , which serve as an anode or cathode, are spacers 15 arranged from tissue. The spacers are necessary to keep it under the influence of high internal pressure within the housing 2 does not come to short circuits. Nevertheless, they allow the gas-liquid mixture in the half-cells to flow as undisturbed as possible.

The electrolytic cell off 5b is different from the one in 5a in that the electrically conductive membrane 17 only on one side with a porous electrode 16a made of fiber material. In the other half cell is the plate 11 covered with a porous surface. In particular, anodes made of chemically resistant materials such as titanium can namely be produced by etching roughening and similar processes for surface modification of solid material.

Example 1:

For hydrogen production by electrolysis of distilled water is a pressure vessel one Volume of 31.4 liters initially filled with 4.7 liters of distilled water. This corresponds a proportion of 15% of the pressure vessel volume. After the electrolysis Remains a residual volume of about 0.5 l of distilled water in Pressure vessel.

The thin-film electrical cells used for the electrolysis have electrodes of 80 mm diameter, each with 5.3 cm ² active area. Cathodes and anodes are fluidly separated by a polymer electrolyte membranes made of Nafion 117 ^® from each other. The cell stack consists of 29 bipolar connected cells, resulting in a construction volume of the cell stack of about 0.7 l. The cathode and anode areas are each 149 cm ² .

The Pressure differences within the cells are measured by a differential pressure gauge and controller actively regulated. The gas-liquid separators contain devices for the catalytic removal of the dissolved oxygen in the anolyte to a platinum black catalyst.

With a volume of the cell stack of 0.7 l, a storage volume of 26.0 l is thus available to the hydrogen to be stored. Converted to normal temperature and atmospheric pressure, the production of hydrogen takes place at a rate of 25 l / h. This corresponds to 1.1 mol / h. In this case, the selected current density of 400 mA / cm ² by means of direct current, for example from a photovoltaic system or a wind turbine.

In 6 the calculated course of the increase in hydrogen pressure is shown as the analysis progresses. It is therefore reached a hydrogen pressure of 200 · 10 ⁵ Pa after about 170 h. As the gas pressure increases, the theoretical decomposition voltage in the individual cells increases from 1.23 V to 1.33 V. The pressure dependence of the decomposition voltage was calculated using the Nernst equation for hydrogen as the real gas using the van der Waals equation calculated. About the electrolysis of the high-pressure hydrogen generator described here can store a constant current of about 60 A for about 211 h. Assuming an electrolysis voltage of about 1.8 V per cell (corresponding to a terminal voltage of the cell stack of 52 V), which corresponds to the storage of electric energy of 655 kWh in a volume of 5.3 m ³ hydrogen gas at normal temperature and normal pressure.

At the beginning of the electrolysis, the pressure in the pressure vessel is 1 × 10 ⁵ Pa with a storage volume of 26.0 l. At the end of the electrolysis after 210 hours, 0.5 l of water remain in the container and the hydrogen pressure has risen to 256 × 10 ⁵ Pa. Therefore, the pressure vessel should be designed with the initial water volume of 15% of the total pressure vessel volume for a maximum operating pressure of 260 x 10 ⁵ Pa.

Example 2

The pressure vessel has an internal volume of 106 l. It is initially filled with 17.9 liters of distilled water, which corresponds to 15% of the pressure vessel volume. After electrolysis, a residual volume of about 1.6 liters of distilled water remains in the pressure vessel. The hydrogen to be stored is thus a storage volume of 88.5 l available. Converted to normal pressure and normal temperature, hydrogen is produced at a current density of 400 mA / cm ² at a rate of 46 l / h, or 2.1 mol / h. The DC power is provided from a photovoltaic system or a rectified external power source such as a wind turbine.

As in Example 1, the electrolytic thin-film cells have electrodes of 80 mm diameter, each with 5.33 cm ² active area. Cathodes and anodes are also separated by a polymer electrolyte membranes made of Nafion 117 ^® from each other as in the example. 1 In the present case, the cell stack is composed of 104 bipolar cells. This leads to a construction volume of the cell stack of about 1.1 l. However, the cathodes and anode area are 275 cm ² each.

The pressure differences within the cells are actively controlled by a differential pressure gauge and regulator. The gas-liquid separators include catalytic removal devices of the dissolved oxygen in the anolyte on a platinum tube catalyst.

About the electrolysis, the high pressure hydrogen generator described here can store a constant current of 110 A for about 380 hours. Assuming an electrolysis voltage of about 1.8 V per cell (corresponds to a terminal voltage of the cell stack of 187 V), this corresponds to the storage of an electrical energy of 7800 kWh in a volume of 17.8 m ^{3 of} hydrogen gas (at atmospheric pressure and normal temperature) ,

At the beginning of the electrolysis, the pressure in the pressure vessel is 1 × 10 ⁵ Pa with a storage volume of 106.0 l. At the end of electrolysis to 380 h was 1.6 l of water remain in the container, and the hydrogen pressure is increased to 247 · 10 ⁵ Pa.

Claims (10)

Electrolysis device ( 1 ), comprising at least one electrolytic cell ( 3 ) with a power connection, with two electrolyte feeds ( 6a , b, 35 ), one as catholyte supply ( 6a ) and the other as anolyte supply ( 6b ), and two gas discharges ( 7a , b) and a high-pressure housing ( 2 ) with a current feedthrough and two gas outlets ( 8a , b), wherein the at least one electrolytic cell ( 3 ) in the housing ( 2 ) and at least one electrolyte feed ( 6a , b, 35 ) inside the housing begins, so that the housing ( 2 ) serves as an electrolyte reservoir, characterized in that one of the gas discharges ( 7b ) with one of the gas outlets ( 8b ) is connected to the discharge of oxygen and the other gas discharge ( 7a ) in the housing interior for the introduction of hydrogen ends, so that the housing ( 2 ) serves as a hydrogen storage, and that at the gas outlets ( 8a , b) a differential pressure regulator ( 24 ) is provided to the pressure difference within the at least one electrolytic cell ( 3 ) as small as possible. Apparatus according to claim 1, characterized in that it is in the housing ( 2 ) around a printing cylinder ( 26 ). Device according to one of claims 1 or 2, characterized in that on the housing ( 2 ) passive coolants ( 28 ) are provided. Device according to one of claims 1 to 3, characterized in that in each electrolyte supply ( 6a , b) a pump ( 25 ) is arranged. Device according to one of claims 1 to 4, characterized in that it is in the at least one electrolysis cell ( 3 ) is a thin-film cell. Device according to one of claims 1 to 5, characterized in that it is in the at least one electrolytic cell ( 3 ) is an arrangement with an electrically conductive membrane. Device according to one of claims 1 to 6, characterized in that it comprises a phase separator ( 23 ) for the gas to be stored ( 5 ). Device according to one of claims 1 to 7, characterized in that a further phase separator ( 23 ) is provided for the other gas. Device according to one of claims 1 to 8, characterized in that the housing ( 2 ) a lid ( 27 ), in which the current leadthrough, the electrolyte inlet ( 38 ) and the two gas outlets ( 8a , b) are integrated. Apparatus according to claim 1 to 9, characterized in that the housing ( 2 ) an electrolyte inlet ( 38 ) having.