DE102021006600A1 - electrolyser system - Google Patents

Abstract

In order to improve the ability of the electrolyzer system (10) to regenerate, it is proposed to equip the electrolyzer device (12) with at least one separator device (36) which is fluidly connected to the electrolyte space (16) and a product gas outlet and which is designed to extract product gas from a liquid side ( 40) to a gas side (42). For this purpose, the electrolyzer system (10) comprises a pressure control device (32), which is set in the operating state in such a way that the fluid flow from the gas space (18, 20) to the separator device (36) is limited in order to have a lower gas pressure on the gas side (42). to generate than on the liquid side (40). Alternatively or additionally, the electrolyzer device (12) can have at least one pump device (28) which is designed to convey the electrolyte (60) in a circuit running through the electrolyte space (16) by generating a gas bubble (48).

Description

The invention relates to an electrolyzer system.

In the case of alkaline and PEM electrolysers, the product gas separation is usually carried out in an external gas separation. There is then no dedicated area for supply water, which means that the water space or electrolyte space is the same as the gas space. Circulation, which is used for cooling at the same time, makes sense for good separation of the large amount of product gas. The relatively high volume flows compared to supply water also ensure good mixing of the electrolyte.

DE 103 06 342 A1 discloses an electrolysis device which has at least one electrolysis cell with a power connection, at least one electrolyte supply and two gas discharge lines and a housing with a power feedthrough and two gas outlets. The electrolytic cell is arranged in the housing. One of the gas discharge lines is connected to one of the gas outlets, the other gas discharge line is located inside the housing and the at least one electrolyte supply begins inside the housing, so that the housing serves both as an electrolyte reservoir and as a gas reservoir.

It is the object of the invention to improve electrolyzer systems, in particular with regard to their ability to regenerate.

The object is solved by the subject matter of the independent claim. Preferred developments are the subject matter of the dependent claims.

1. a) wenigstens eine Abscheideeinrichtung, die mit dem Elektrolytraum und wenigstens einem der Gasräume sowie einem Produktgasausgang fluidverbunden ist und die ausgebildet ist, Gas von einer Flüssigkeitsseite zu einer Gasseite durchzulassen, wobei das Elektrolyseursystem ferner wenigstens eine Druckregeleinrichtung umfasst, die in Fluidflussrichtung zwischen einem der Gasräume und der Abscheideeinrichtung geschaltet ist, wobei die Druckregeleinrichtung im Betriebszustand derart ist, dass der Fluidfluss von dem Gasraum zum der Abscheideeinrichtung derart zu begrenzt ist, dass auf der Gasseite ein geringerer Gasdruck herrscht als auf der Flüssigkeitsseite; und/oder
2. b) wenigstens eine Pumpeinrichtung, die ausgebildet ist, den Elektrolyten in einem durch die Matrixzelle verlaufenden Kreislauf mittels Erzeugung einer Gasblase zu fördern.

The invention provides an electrolyzer system that is designed to electrolyze an aqueous electrolyte, the electrolyzer system comprising an electrolyzer device with at least one matrix cell that has an electrolyte space, a cathodic gas space and an anodic gas space, and at least one of the following features:

1. a) at least one separating device which is in fluid communication with the electrolyte space and at least one of the gas spaces as well as a product gas outlet and which is designed to allow gas to pass through from a liquid side to a gas side, the electrolyzer system also comprising at least one pressure control device which is arranged between one of the gas spaces in the fluid flow direction and the separating device, the pressure control device being in the operating state in such a way that the fluid flow from the gas space to the separating device is limited in such a way that the gas pressure on the gas side is lower than that on the liquid side; and or
2. b) at least one pump device which is designed to convey the electrolyte in a circuit running through the matrix cell by generating a gas bubble.

It is preferred that the separating device comprises a cathodic gas separator which is fluidly connected on its gas side to the cathodic gas space and a cathodic product gas outlet and on its liquid side to the electrolyte space.

It is preferred that the cathodic gas separator has a separator membrane configured to pass cathodic product gas from the liquid side to the gas side.

It is preferred that the separating device comprises an anodic gas separator which is fluidly connected on its gas side to the anodic gas space and an anodic product gas outlet and on its liquid side to the liquid side of the cathodic gas separator.

It is preferred that the pumping device is fluidly connected to the separating device and the electrolyte space in order to convey the electrolyte through the matrix cell in the circuit.

It is preferred that the pump device is fluidly connected to the liquid side of the cathodic gas separator and/or to the liquid side of the anodic gas separator.

It is preferred that the pumping device comprises a capillary area, which is designed to widen in the direction of fluid flow in order to force a gas bubble in the direction of fluid flow, with a pumping electrode being arranged adjacent to the capillary area, to which electrical potential can be applied in such a way that in the capillary area a Gas bubble can be generated from the electrolyte.

It is preferred that the capillary area is arranged in the fluid flow direction between the electrolyzer device and the separator device and is fluidly connected to them.

It is preferred that the electrolyzer system contains the aqueous electrolyte when ready for operation

It is preferred that the electrolyte contains a venting additive designed to contain Ver to promote melting of small gas bubbles into a larger gas bubble.

It is preferred that the electrolyte contains a viscosity modifying additive configured to change the viscosity of the electrolyte compared to the viscosity of the electrolyte without a corresponding additive.

It is preferred that the electrolyte contains a defoaming additive designed to reduce the likelihood of liquid interfaces forming to facilitate gas transport.

It is preferred that the electrolyte contains a magneto-rheology additive designed to enhance the interaction between the electrolyte and a magnetic field.

It is preferred that the electrolyte contains an electrorheology additive designed to increase the interaction between the electrolyte and an electric field.

It is preferred that the electrolyte contains a ferrofluid.

It is preferred that the electrolyte contains a metal configured to form a metal hydride together with hydrogen for temporary storage of the hydrogen.

It is preferred that the electrolyte contains a liquid organic hydrogen carrier (LOHC) system for temporary storage of the hydrogen.

It is preferred that the matrix cell has a cathode electrode and an anode electrode.

It is preferred that the cathodic gas space is arranged adjacent to the electrolyte space and separated therefrom by a gas-tight first diaphragm. It is preferred that the cathodic gas space and the cathode electrode are configured such that, due to energization of the cathode electrode, a cathodic product gas can be generated at an interface of the cathode electrode with the first diaphragm in such a way that it can flow into the cathodic gas space.

It is preferred that the anodic gas space is located adjacent to the electrolyte space and separated therefrom by a gas-tight second diaphragm. It is preferred that the anodic gas space and the anode electrode are configured such that, due to energization of the anode electrode, anodic product gas can be generated at an interface of the anode electrode with the second diaphragm in such a way that it can flow into the cathodic gas space.

It is preferred that the matrix cell comprises a preferably electrolyte-tight degassing device which is designed to selectively allow product gas in the electrolyte space to escape into at least one of the gas spaces.

It is preferred that the degassing device and preferably its additional components is/are configured for continuous and/or discontinuous operation of the matrix cell, in particular degassing operation for degassing the electrolyte space. It is preferred that at least one diaphragm is designed as a degassing membrane.

It is preferred that the degassing device is designed to selectively allow cathodic product gas located in the electrolyte space to escape into the cathodic gas space.

It is preferred that the degassing device is arranged in a degassing opening formed in at least one diaphragm in order to create a selective passage for the product gas from the electrolyte space into at least one of the gas spaces.

It is preferred that the degassing device is arranged in a degassing opening formed in the first diaphragm in order to create a selective passage for the cathodic product gas from the electrolyte space into the cathodic gas space.

It is preferred that the degassing device is designed to allow cathodic product gas located in the electrolyte space to exit into the cathodic gas space.

It is preferred that the degassing device has a selective degassing membrane which is designed to selectively let predominantly the cathodic or the anodic product gas through.

It is preferred that the degassing device comprises at least one degassing membrane layer structure having a hydrophilic or hydrophobic degassing membrane.

It is preferable that the degassing means comprises a degassing membrane layered structure comprising a hydrophobic degassing membrane and a hydrophilic degassing membrane, wherein the hydrophobic degassing membrane is sandwiched between the hydrophilic degassing membrane and the electrolyte space is arranged in such a way that the hydrophobic degassing membrane comes into contact with the electrolyte in the operating state.

It is preferred that the hydrophilic degassing membrane is arranged in contact with the diaphragm in such a way that the hydrophilic degassing membrane can be wetted with the electrolyte exclusively via the diaphragm.

It is preferred that the degassing device is designed to be brought or switched into a state in which gas bubbles can be generated in a hydrophilic degassing membrane.

It is preferred that an electrical potential can be applied to the hydrophilic degassing membrane in such a way that the gas bubbles can be generated in the hydrophilic degassing membrane.

It is preferred that the hydrophilic degassing membrane can be electrically connected to the cathode electrode and/or the anode electrode via a switch.

It is preferred that at least one degassing membrane is a porous membrane designed to transport product gas via pores.

It is preferred that at least one degassing membrane is a solution-diffusion membrane configured to transport product gas dissolved in the membrane by diffusion.

It is preferred that at least one degassing membrane is a functional membrane that is non-porous and water- and/or ion-conducting.

It is preferred that at least one degassing membrane, preferably the hydrophilic degassing membrane, has a lower bubble point pressure than the diaphragm, above which gas can flow through the degassing membrane.

It is preferred that the degassing device contains a valve that can be controlled and/or regulated independently or actively.

The matrix cell preferably also includes an ultrasound generating device which is designed to generate ultrasonic waves in the matrix cell, preferably in the electrolyte space.

It is preferred that the ultrasound generating device has at least one piezo sound generator that is integrated into the matrix cell.

It is preferred that the ultrasonic device is electrically connected in such a way that it can be excited by an alternating voltage superimposed on the operating voltage.

Preferably, the matrix cell also includes a field generating device that is designed to generate an electric and/or a magnetic field that is configured in such a way that a flow of the electrolyte can be generated in the electrolyte space in the fluid flow direction.

The electrolyser is based on matrix cells, i.e. essentially a fixed electrolyte. In this case, the water and gas spaces are separated from one another, which means that neither gas separation nor circulation is required. The aim is to reduce the risk of inhomogenization of the electrolyte concentration or of gas accumulations or stuck gas bubbles in channels and structures. These can be determined, for example, by gas diffusion with corresponding temperature gradients (solubility limit) or external electrolysis, external electrolysis being an electrolysis that takes place in an area that is not intended for this purpose. The causes are usually unavoidable potential differences on parts with contact with the electrolyte.

One idea is to perform gas separation. Since the concept is determined by a dry gas space, the supply water or electrolyte must be retained while the water space or electrolyte space is (almost) completely filled. The degassing takes place at an overpressure of the gas accumulation compared to a product gas (for example H ₂ ). At the same time, however, this means that water can be pumped into the gas space in the lower area due to the hydrostatic pressure, depending on the type of diaphragm. Various concepts can be derived from this, whereby these can also be combined with one another and the recirculation to a specific product gas is by no means intended.

For example, with a hydrophobic membrane, continuous outgassing is possible, while the hydrophobic property better protects against overfilling of the headspace. Depending on the installation position, excess water pressure may be required to prevent product gases from being sucked into the water space. However, it should be noted that the overpressure does not necessarily lead to the gas space being filled, as this can be counteracted by higher current intensities and the flow resistance of the diaphragm. Nevertheless, it is a degassing option according to the invention.

A hydrophilic membrane can stop gas flow after wetting with a liquid. This enables a strong negative pressure in the electrolyte space compared to the gas space. A filling of the water space with product gases is therefore almost impossible, while overfilling with electrolyte remains avoidable despite good electrolyte distribution. A targeted opening of the membrane may be necessary for degassing. This can be done operationally by exceeding the bubble pressure or by otherwise removing the water from the membrane structure, which could be, inter alia, electrochemical.

$$U_{Mmembran}=\frac{b}{a}\cdot U_{Zelle}$$

The membrane can be a silver membrane. This is in the electric field between the electrodes with the potentials φ _1/2 . Due to induction, the potential of the membrane φ ₃ is determined by the distances a and b from the electrode (e.g. anode). $$\frac{{\phi }_2-{\mathrm{<figure-callout\; id="1"\; label="\phi "\; filenames="DE102021006600A1\_0008.png"\; state="\{\{state\}\}">\phi </figure-callout>}}_1}{{\phi }_3-{\mathrm{<figure-callout\; id="1"\; label="\phi "\; filenames="DE102021006600A1\_0008.png"\; state="\{\{state\}\}">\phi </figure-callout>}}_1}=\frac{a}{b}=\frac{u_{Zelle}}{u_{Memb\mathrm{right}an}}$$

$$u_{Mmemb\mathrm{right}an}=\frac{b}{a}\cdot u_{Zelle}$$

When the voltage between the membrane and an electrode exceeds the decomposition voltage, electrolysis occurs inside the membrane. The resulting gas bubbles can push out the electrolyte and thus open the membrane. The design can be selected accordingly in order to use this as a safety function with high cell voltages. Alternatively, a sufficient potential difference can be enforced, for example, but not only, with a short circuit with the counter electrode (e.g. cathode).

The gas composition of the accumulations is only determined by the electrolyte. As a rule, it is therefore hydrogen and oxygen. Targeted gas recirculation can be useful, especially when a high degree of gas purity is required, but also for safety reasons. These can be both porous and solution-diffusion membranes or functional membranes. Although the functional membrane does not have any pores, it is still designed to conduct water and ions. For example, the selectivity of hydrogen over oxygen is crucial.

The properties can be further influenced by combining different membrane types. Gas evacuation from the water side to the gas side is desired, while vice versa this should be prevented. This property can be achieved by a multi-layer structure of hydrophilic and hydrophobic membrane. A hydrophilic side is supplied with water/electrolyte on the gas side via capillary effects and thus forms a gas-impermeable film on the hydrophobic membrane, while in the opposite direction the gas can pass through the hydrophilic side due to a low bubble pressure.

The solution-diffusion mechanism relies on the partial pressures and not the total pressures. For this reason, this type of membrane does not affect the regulation of the water balance. However, it must be taken into account that the necessary partial pressure difference for transport only exists towards another gas, for example hydrogen in oxygen. In order to keep gas pollution low, a recombination catalyst is useful.

Gas extraction or degassing can be promoted by other measures.

Degassing can be carried out not only internally, but also externally. This allows a new pressure level to be created on the gas side, which removes limitations in the required pressure settings in the cell. The gas pressure is lowered with a metering valve in front of the membrane, for example, whereby the pressure drop facilitates degassing. Separation on both sides of the process gas is provided on the right. Here, the oxygen is concentrated by a hydrogen-selective membrane, which is separated in a series-connected hydrophobic membrane. Although this does not generally require a forced flow, this can have a beneficial effect on the transport of gas bubbles. In addition, all of the aforementioned membranes and combinations thereof can be used.

Bubbles getting stuck in thin channels is particularly problematic in the case of external degassing. One solution is pumping around for process gas separation. Since the gas production here is only in the per thousand range compared to the process gas, the leakage currents, which are the main cause of the gas accumulations, can be used for pumping. The influence of the capillary effect on the movement of a bubble in an expanding capillary is used. The gas bubble can also be generated specifically within the channel with an electrochemically active surface. Due to its potential compared to the cells, the speed can also be adjusted.

Within the water supply layer, matrix cells mainly have a structure that serves to fix the electrolyte. Bubbles in this area are a hindrance, since they usually cannot be expelled by pumps. The use of special vents is helpful here tion additives that promote the merging of several smaller air bubbles into one large one and thus the ascent to the surface. In addition to deaerators, the use of viscosity-reducing additives or defoamers is also conceivable.

Ultrasound can act in a similar way to deaerators. Gas bubbles can fuse and then be transported away more easily, with the ultrasound also having an effect on other gases in solution and contributing to the concentration homogenization in the electrolyte. Penetrating an entire stack with ultrasound is difficult, since very high power is required. Appropriate ultrasonic transmitters, mainly piezoceramics, can be integrated directly into the water supply layer of each cell, which means that the power required to penetrate the entire stack can be reduced. The electrical connection can, but does not have to, take place via the potential of the electrodes. Superimposition of the supply current with the resonant frequency of the transducer can serve to activate the ultrasound.

In an electrolytic cell, the ions in the electrolyte move due to an electric field. This usually requires high currents at the same time, which also form a magnetic field. With magnetoelectrochemistry it can be explained that due to the magnetic field, a convection of ions can occur parallel to the electrode surface. Both effects (electrical and magnetic) can be used in a targeted manner to create a flow within the water space of a matrix cell. In addition to gas bubble transport, this primarily serves to support diffusion to homogenize the electrolyte. For example, alternating fields could be introduced into the water supply layer with the help of electrical conductors, or the effect could be significantly influenced by adding additives. A distinction must be made here between magnetorheological, electrorheological liquids and ferrofluids.

As already noted, the generation of unwanted gas bubbles is typically very small compared to the amount of product gas. Temporary storage with regeneration can be an option, particularly in the case of pressure electrolysis and cyclic operation. For example, metal hydrides or LOHC can also be introduced into the space of the electrolyte.

• 1 ein Ausführungsbeispiel eines Elektrolyseursystems;
• 2 ein weiteres Ausführungsbeispiel eines Elektrolyseursystems;
• 3 ein weiteres Ausführungsbeispiel eines Elektrolyseursystems;
• 4 eine schematische Darstellung einer Gasblasenförderung;
• 5 ein Ausführungsbeispiel einer Matrixzelle für ein Elektrolyseursystem; und
• 6 eine Detaildarstellung einer Entgasungseinrichtung der Matrixzelle.

Exemplary embodiments are explained in more detail below with reference to the accompanying schematic drawings. It shows:

• 1 an embodiment of an electrolyzer system;
• 2 another embodiment of an electrolyzer system;
• 3 another embodiment of an electrolyzer system;
• 4 a schematic representation of a gas bubble promotion;
• 5 an embodiment of a matrix cell for an electrolyzer system; and
• 6 a detailed representation of a degassing device of the matrix cell.

It will be referred to below 1 Reference is made, which shows an example of an electrolyzer system 10 . The electrolyzer system 10 includes an electrolyzer device 12. The electrolyzer device 12 includes a plurality of matrix cells 14. Each matrix cell 14 has an electrolyte space 16, a cathodic gas space 18 and an anodic gas space 20. FIG. The electrolyte space 16 is separated from the gas spaces 18, 20 by a diaphragm 22 in each case. The diaphragm 22 is designed to allow gas that has formed or is present in the electrolyte space 16 to pass into the gas spaces 18 , 20 . At the same time, the diaphragm 22 separates the gases from one another, including gas that has formed or is present in the electrolyte space 16 and separates it from the gas spaces 18, 20.

The electrolyzer system 10 includes a cathodic product gas outlet 24 and an anodic product gas outlet 26. The respective gas can be removed from the product gas outlets 24, 26 and stored, for example, in a gas cylinder not shown in detail here. The electrolyzer system 10 includes a pumping device 28. The pumping device 28 is designed to convey the electrolyte in an electrolyte circuit 30 which contains the electrolyte space 16.

The electrolyzer system 10 includes a pressure control device 32. The pressure control device 32 is designed to adjust the gas flow that escapes from the gas chambers 18, 20. The pressure control device 32 includes a metering valve 34 which is arranged between the cathodic gas space 18 and the cathodic product gas outlet 24 and is in fluid communication with each of them.

The electrolyzer system 10 includes a separating device 36. The separating device 36 includes a cathodic gas separator 37 with a separating membrane 38. The separating membrane 38 separates the liquid side 40 from the gas side 42. The separating membrane 38 is designed in such a way that gas on the liquid side 40 passes through the separating membrane 38 is transported through to the gas side 42.

The functioning of the electrolyzer system 10 is explained in more detail below.

The electrolyzer device 12 electrolyzes the water in the aqueous electrolyte in the matrix cell 14 into cathodic product gas (here: hydrogen) and anodic product gas (here: oxygen). The cathodic product gas flows from the cathodic gas space 18 through the metering valve 34 to the cathodic product gas outlet 24. However, due to the metering valve 34, the gas pressure of the cathodic product gas is reduced downstream.

Undesired cathodic product gas can still be present in the electrolyte, which is conveyed in the electrolyte circuit 30 with the aid of the pump device 28 . This flows along the electrolyte circuit 30 into the cathodic gas separator 37 of the separating device 36. Due to the lower gas pressure of the cathodic product gas on the gas side 42, any remaining cathodic product gas is transported through the separating membrane 38 to the gas side 42 and thus also reaches the cathodic product gas outlet 24 .

The anodic product gas is routed directly from the anodic gas space 20 to the anodic product gas outlet 26 .

Regarding 2 a further exemplary embodiment of the electrolyzer system 10 is explained in more detail. The electrolyzer system 10 is only explained insofar as it differs from the exemplary embodiment described so far.

As in 2 shown, the pressure control device 32 includes a further metering valve 35. The further metering valve 35 is arranged between the anodic gas space 20 and the anodic product gas outlet 26 and is fluidly connected to these. The other metering valve 35 works essentially like the metering valve 34.

As also in 2 shown, the separating device 36 additionally comprises an anodic gas separator 39. The anodic gas separator 39 is designed similarly to the cathodic gas separator 37, with the proviso that the separating membrane 38 of the anodic gas separator 39 is designed to transport the anodic product gas to its gas side 42 .

The functioning of this electrolyzer system 10 is briefly explained in more detail below. As before, in the matrix cell 14 the electrolysis of the electrolyte takes place. In the cathodic gas separator 37 undesired cathodic product gas is transported from the electrolyte to the gas side 42 and to the cathodic product gas outlet 24 . This further increases the relative concentration of anodic product gas in the electrolyte. The concentrated anodic product gas is transported with the aid of the anodic gas separator 39 through its separating membrane 38 on its gas side 42 and to the anodic product gas outlet 26 . The additional metering valve 35 also lowers the pressure of the anodic product gas on the gas side 42 here, so that anodic product gas can escape more easily through the separation membrane 38 of the anodic gas separator 39 .

It will be referred to below 3 and 4 Reference is made which shows another embodiment of the electrolyzer system 10 . As in 3 shown in more detail, the electrolysis device 12 comprises a plurality (here six) of matrix cells 14. The matrix cells 14 are charged with the electrical potentials φ ₁ to φ ₇ in order to carry out the electrolysis.

The pumping device 28 conveys the electrolyte with the aid of gas bubbles. The pumping device 28 has a capillary region 44 which widens in the direction of the fluid flow. Furthermore, the pumping device 28 comprises an electroactive surface 46 adjacent to the capillary region 44 , to which an electrical potential φ _pump can be applied relative to one of the potentials of the matrix cells 14 . As a result, external electrolysis takes place outside of the matrix cells 14 and creates a gas bubble 48.

The principle is explained in more detail with reference to 4 explained. As in 4 , shown on the left, the gas bubble 48 in the capillary area 44 is accelerated in the direction of the arrow due to the different capillary pressure. The speed increases, as in 4 , shown in the middle, continues to decrease due to the decreasing pressure difference. Finally, the gas bubble comes to a standstill ( 4 , right) when the gas bubble 48 has reached a spherical shape and thus identical capillary pressures in front of and behind it.

However, at this point the gas bubble 48 was in motion and will continue to be in motion due to the inertia of the liquid and the constant formation of new gas bubbles 48 . The gas bubble 48 takes the electrolyte 60 with it along its entire path, so that overall the electrolyte 60 is transported from the narrower to the wider side of the capillary region 44 . In this way, the electrolyte 60 can be conveyed in the electrolyte circuit 30 without moving parts.

It will be referred to below 5 and 6 Reference is made, on the basis of which the structure of the matrix cell 14 is explained in more detail.

As already described, the matrix cell 14 comprises the electrolyte space 16, the cathodic gas space 18, the anodic gas space 20 and the diaphragms 22.

Furthermore, the matrix cell 14 comprises a degassing device 50. The degassing device 50 is preferably arranged in a degassing opening 52 which is formed in at least one of the diaphragms 22.

The degassing device 50 can, as in 5 shown in more detail, have a degassing layer structure 54 . The outgas layer structure 54 comprises a hydrophilic outgas membrane 56 and a hydrophobic outgas membrane 58. The hydrophobic outgas membrane 58 is arranged between the electrolyte 60 and the hydrophilic outgas membrane 56. FIG. The hydrophilic degassing membrane 56 is wetted with the electrolyte 60 via the diaphragm 22 .

The degassing device 50 also includes a hydrophilic degassing membrane 62. The hydrophilic degassing membrane 62 can be a silver membrane, for example. The hydrophilic degassing membrane 62 is arranged in the degassing opening 52 and is in direct contact with the electrolyte 60 and the diaphragm 22.

The matrix cell 14 further includes a cathode electrode 64 and an anode electrode 66 . The cathode electrode 64 can be electrically connected to the hydrophilic degassing membrane 62 via a switch 68 . The switch 68 can generally also be part of a control device and can be controlled by software. It can also be an integrated circuit or the like.

The matrix cell 14 can also have an ultrasound generating device 70 . The ultrasonic generating device 70 is designed to convert electrical alternating voltage into ultrasonic waves. The ultrasound generating device 70 comprises at least one ultrasound transducer 72. The ultrasound transducer 72 can be a piezoceramic, for example. The ultrasonic transducer 72 is, for example, arranged adjacent to the electrodes 64 , 66 and aligned in such a way that the ultrasonic waves can penetrate into the electrolyte space 16 .

The matrix cell 14 can have a field generating device 74 . The field generating device 74 is designed to generate an electric, a magnetic or an electromagnetic field. The field generating device 74 comprises a plurality of field electrodes 76. The field electrode 76 can, for example, be arranged adjacent to the electrodes 64, 66 or integrated into them.

Below is in particular based on the 6 the functioning of the matrix cell 14 is explained in more detail.

First, the cathode electrode 64 and the anode electrode 66 are charged with electrical potentials phi 1 and phi 2 . The potential difference is chosen so that electrolysis of the electrolyte 60 can take place at the interface between the respective electrode 64, 66 and the diaphragm 22. The product gas bubbles 78 created by the electrolysis move from the interface to the gas space. Gas (mainly product gas) that has entered the electrolyte space 16 undesirably, for example as a result of external electrolysis or other circumstances, can be transported with the aid of the degassing layer structure 74 through the hydrophobic degassing membrane 58 and then through the hydrophilic degassing membrane 56 and thus reaches the cathodic gas space 18.

If, for example, there is a risk of an electrolyte deficiency in the electrolyte space 16 and an overvoltage would therefore arise between the electrodes 64 and 66 , the hydrophilic degassing membrane 62 can be short-circuited with the cathode electrode 64 . This changes the electrical potential of the hydrophilic degassing membrane 62 so that electrolysis now also takes place within the hydrophilic degassing membrane 62 . This can also be caused by a higher voltage between the electrodes 64 and 66. The gas bubbles generated in the hydrophilic degassing membrane 62 open the hydrophilic degassing membrane 62 and allow excess product gas to escape into the cathodic gas space 18 .

In addition, the ultrasound generating device 70 can emit ultrasound into the electrolyte space 16 in order to loosen any stuck product gas bubbles 78 or to combine smaller product gas bubbles into fewer but larger product gas bubbles.

Since the electrolysis of the electrolyte 60 is accompanied by ion movements, the field generating device 74 can be used to generate a flow of the electrolyte 60 within the matrix cell 14, for example from bottom to top.

In order to improve the regeneration capability of the electrolyzer system 10, it is proposed to use matrix cells 14. The electrolyte 60 is electrolyzed in the matrix cell 14 . Unwanted gas (mainly product gas) that has entered the electrolyte chamber 16 is removed by a degassing device 50 is transported away from the electrolyte space 16 into the gas space 18 provided for this purpose. Additional measures such as ultrasonic transducers 72 and field electrodes 76 can achieve an electrolyte flow and better gas evacuation.

Reference List

10

electrolyser system

12

electrolyser device

14

matrix cell

16

electrolyte compartment

18

cathodic gas space

20

anodic gas space

22

diaphragm

24

cathodic gas outlet

26

anodic gas outlet

28

pumping device

30

electrolyte circuit

32

pressure control device

34

dosing valve

35

another dosing valve

36

separation device

37

cathodic gas separator

38

separation membrane

39

anodic gas separator

40

liquid side

42

gas side

44

capillary area

46

electroactive surface

48

gas bubble

50

degassing device

52

vent hole

54

degassing view structure

56

hydrophilic degassing membrane

58

hydrophobic degassing membrane

60

electrolyte

62

hydrophilic degassing membrane

64

cathode electrode

66

anode electrode

68

Switch

70

ultrasonic generating device

72

ultrasonic transducer

74

field generating device

76

field electrode

78

product gas bubble

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 10306342 A1 [0003]

Claims (13)

Electrolyzer system (10) designed to electrolyze an aqueous electrolyte (60), the electrolyzer system (10) having an electrolyzer device (12) with at least one matrix cell (14), which has an electrolyte space (16), a cathodic gas space (18) and has an anodic gas space (20), wherein the electrolyzer device (12) comprises at least one of the following features: a) at least one separating device (36) which is fluidly connected to the electrolyte space (16) and a product gas outlet and which is designed to allow product gas to pass from a liquid side (40) to a gas side (42), the electrolyzer system (10) having at least one pressure control device (32) which is connected in the fluid flow direction between one of the gas spaces (18, 20) and the separating device (36), the pressure control device (32) being set in the operating state in such a way that the fluid flow from the gas space (18, 20) to the separating device (36) is limited in such a way that there is a lower gas pressure on the gas side (42) than on the liquid side (40); and or b) at least one pump device (28) which is designed to convey the electrolyte (60) in a circuit running through the electrolyte space (16) by generating a gas bubble (48). Electrolyzer system (10) according to claim 1 , further comprising at least one pressure control device (32), which is connected in the fluid flow direction between one of the gas spaces (18, 20) and the separating device (36), wherein the pressure control device (32) is designed to regulate the fluid flow from the gas space (18, 20) to the separating device (36) in such a way that there is a lower gas pressure on the gas side (42) than on the liquid side (40). Electrolyzer system (10) according to one of the preceding claims, wherein the separating device (36) comprises a cathodic gas separator (37) which is connected on its gas side (42) to the cathodic gas space (18) and a cathodic product gas outlet and on its liquid side (40) to the electrolyte space (16) is fluidly connected. An electrolyzer system (10) according to any one of the preceding claims, wherein the cathodic gas separator (37) comprises a separator membrane (38) adapted to pass cathodic product gas from the liquid side (40) to the gas side (42). Electrolyzer system (10) according to one of the preceding claims, wherein the separating device (36) comprises an anodic gas separator (39) which is connected on its gas side (42) to the anodic gas space (20) and an anodic product gas outlet and on its liquid side (40) to the liquid side (40) of the cathodic gas separator (37) is fluidly connected. Electrolyzer system (10) according to one of the preceding claims, wherein the pumping device (28) is fluidly connected to the separator device (36) and the electrolyte compartment (16) in order to convey the electrolyte (60) through the matrix cell (14) in the circuit. Electrolyser system (10) according to any one of the preceding claims, wherein the pumping means is fluidly connected to the liquid side of the cathodic gas separator and/or to the liquid side of the anodic gas separator. Electrolyzer system (10) according to one of the preceding claims, wherein the pumping device (28) comprises a capillary region (44) which is designed to widen in the direction of fluid flow in order to urge the gas bubble (48) in the direction of fluid flow, being adjacent to the capillary region (44). a pumping electrode is arranged, which can be subjected to electrical potential in such a way that the gas bubble (48) can be generated from the electrolyte (60) in the capillary region (44). Electrolyzer system (10) according to claim 8 , wherein the capillary region (44) is arranged in the fluid flow direction between the electrolyzer device (12) and the separator device (36) and is fluidly connected to them. The electrolyzer system (10) of any preceding claim, further comprising an aqueous ready-state electrolyte (60). Electrolyzer system (10) according to claim 10 wherein the electrolyte (60) a) contains a bleed additive configured to promote the merging of small gas bubbles into a larger gas bubble; and/or b) contains a defoaming additive designed to reduce the likelihood of liquid interface formation to facilitate gas transport. Electrolyzer system (10) according to one of Claims 10 or 11 wherein the electrolyte (60) a) contains a metal adapted to form, together with hydrogen, a metal hydride for the temporary storage of the hydrogen; and/or b) contains a liquid organic hydrogen carrier system for the temporary storage of hydrogen. Electrolyzer system (10) according to one of Claims 10 until 12 wherein the electrolyte (60) a) includes a viscosity modifying additive configured to modify the viscosity of the electrolyte compared to the viscosity of the electrolyte without the corresponding additive; and/or b) contains a magneto-rheology additive designed to increase the interaction between the electrolyte and a magnetic field; and/or c) contains an electrorheology additive designed to increase the interaction between the electrolyte and an electric field.

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